pubMedId
stringlengths 1
2.98k
| title
stringlengths 1
1.9k
⌀ | abstract
stringlengths 1
14.2k
⌀ |
|---|---|---|
20192045 | How to ensure patient observations lead to effective management of tachycardia. | Tachycardia is a normal physiological response to exercise but in the healthcare setting it is considered to be an adverse sign, indicating possible serious illness such as shock. The condition can also be associated with a life threatening cardiac arrhythmia. This article aims to help nurses understand how to manage it. |
20192052 | Web-based multi-center data management system for clinical neuroscience research. | Modern clinical research often involves multicenter studies, large and heterogeneous data flux, and intensive demands of collaboration, security and quality assurance. In the absence mercial or academic management systems, we designed an open-source system to meet these requirements. Based on the Apache-PHP-MySQL platform on a Linux server, the system allows multiple users to access the database from any location on the internet using a web browser, and requires no puter skills. Multi-level security system is implemented to safeguard the protected health information and allow partial or full access to the data by individual or class privilege. The system stores and manipulates various types of data including images, scanned documents, laboratory data and clinical ratings. Built-in functionality allows for various search, quality control, analytic data operations, visit scheduling and visit reminders. This approach offers a solution to a growing need for management of large multi-center clinical studies. |
20192053 | Application of K- and fuzzy c-means for color segmentation of thermal infrared breast images. | Color segmentation of infrared thermal images is an important factor in detecting the tumor region. The cancerous tissue with angiogenesis and inflammation emits temperature pattern different from the healthy one. In this paper, two color segmentation techniques, K-means and fuzzy c-means for color segmentation of infrared (IR) breast images are modeled pared. Using the K-means algorithm in Matlab, some empty clusters may appear in the results. Fuzzy c-means is preferred because the fuzzy nature of IR breast images helps the fuzzy c-means segmentation to provide more accurate results with no empty cluster. Since breasts with malignant tumors have higher temperature than healthy breasts and even breasts with benign tumors, in this study, we look for detecting the hottest regions of abnormal breasts which are the suspected regions. The effect of IR camera sensitivity on the number of clusters in segmentation is also investigated. When the camera is ultra sensitive the number of clusters being considered may be increased. |
20192054 | An optimization model for locating and sizing emergency medical service stations. | Emergency medical services (EMS) play a crucial role in the overall quality and performance of health services. The performance of these systems heavily depends on operational success of emergency services in which emergency vehicles, medical personnel and supporting equipment and facilities are the main resources. Optimally locating and sizing of such services is an important task to enhance the responsiveness and the utilization of limited resources. In this study, an integer optimization model is presented to decide locations and types of service stations, regions covered by these stations under service constraints in order to minimize the total cost of the overall system. The model can produce optimal solutions within a reasonable time for large cities having up to 130 districts or regions. This model is tested for the EMS system of Adana metropolitan area in Turkey. Case study putational findings of the model are discussed in detail in the paper. |
20192047 | How to use coaching and action learning to support mentors in the workplace. | Using the example of mentoring preregistration student nurses, this article explores facilitation of learning in the workplace and examines the use of coaching and action learning to support mentors and the wider clinical team. A case study, where a mentor has difficulties with an underperforming student, is considered. Action learning and coaching are then explored, with the aim of maximising personal and team learning. These strategies can be easily transferred to other work based learning situations. |
20192055 | Improving mental task classification by adding high frequency band information. | Features extracted from delta, theta, alpha, beta and gamma bands spanning low frequency range monly used to classify scalp-recorded electroencephalogram (EEG) for designing puter interface (BCI) and higher frequencies are often neglected as noise. In this paper, we implemented an experimental validation to demonstrate that high ponents could provide helpful information for improving the performance of the mental task based BCI. Electromyography (EMG) and electrooculography (EOG) artifacts were removed by using blind source separation (BSS) techniques. Frequency band powers and asymmetry ratios from the high frequency band (40-100 Hz) together with those from the lower frequency bands were used to represent EEG features. Finally, Fisher discriminant analysis bining with Mahalanobis distance were used as the classifier. In this study, four types of classifications were performed using EEG signals recorded from four subjects during five mental tasks. We obtained significantly higher classification accuracy by adding the high frequency band pared to using the low frequency bands alone, which demonstrated that the information in high ponents from scalp-recorded EEG is valuable for the mental task based BCI. |
20192057 | Novel approach to fuzzy-wavelet ECG signal analysis for a mobile device. | This paper describes a signal processing technique for ECG signal analysis based upon bination of wavelet analysis and fuzzy c-means clustering. The signal analysis technique is implemented into a biomedical signal diagnostic unit that is the carry on device for the Wireless Nano-Bios Diagnostic System (WNBDS) developed at National Taiwan University. The WNBDS integrates mobile devices and remote data base servers to conduct online monitoring and remote healthcare applications. The signal analysis and diagnostic algorithms in this paper are implemented in an embedded mobile device to conduct mobile biomedical signal diagnostics. At this stage, the Electrocardiogram (ECG or EKG) is analyzed for patient health monitoring. The ECG signal processing is based on the wavelet analysis, and the diagnosis is based on fuzzy clustering. The embedded system is realized with the Windows CE operating system. |
20192056 | Optimal resource allocation model to mitigate the impact of pandemic influenza: a case study for Turkey. | Pandemic influenza has been considered as a serious international health risk by many health authorities in the world. In mitigating pandemic influenza, effective allocation of limited health resources also plays a critical role along with effective use of medical prevention and treatment procedures. A national resource allocation program for prevention and treatment must be supported with the right allocation decisions for all regions and population risk groups. In this study, we develop a multi-objective mathematical programming model for optimal resource allocation decisions in a country where a serious risk of pandemic influenza may exist. These resources include monetary budget for antivirals and preventive vaccinations, intensive care unit (ICU) beds, ventilators, and non-intensive care unit (non-ICU) beds. The mathematical model has three objectives: minimization of number of deaths, number of cases and total morbidity days during a pandemic influenza. This model can be used as a decision support tool by decision makers to assess the impact of different scenarios such as attack rates, hospitalization and death ratios. These factors are found to be very influential on the allocation of the total budget among preventive vaccination, antiviral treatment and fixed resources. The data set collected from various sources for Turkey is used and analyzed in detail as a case study. |
20192059 | Comparison of wavelet and short time Fourier transform methods in the analysis of EMG signals. | The electromyographic (EMG) signal observed at the surface of the skin is the sum of thousands of small potentials generated in the muscle fiber. There are many approaches to analyzing EMG signals with spectral techniques. In this study, the short time Fourier Transform (STFT) and wavelet transform (WT) were applied to EMG signals and coefficients were obtained. In these studies, MATLAB 7.01 program was used. According to obtained results, it was determined that WT is more useful than STFT in the fields of eliminating of resolution problem and providing of changeable resolution during analyze. |
20192058 | Determination of sleep stage separation ability of features extracted from EEG signals using principle component analysis. | In this study, a method was proposed in order to determine how well features extracted from the EEG signals for the purpose of sleep stage classification separate the sleep stages. The proposed method is based on the ponent analysis known also as the Karhunen-Loéve transform. Features frequently used in the sleep stage classification studies were divided into three main groups: (i) time-domain features, (ii) frequency-domain features, and (iii) hybrid features. That how well features in each group separate the sleep stages was determined by performing extensive simulations and it was seen that the results obtained are in agreement with those available in the literature. Considering the fact that sleep stage classification algorithms consist of two steps, namely feature extraction and classification, it will be possible to tell a priori whether the classification step will provide successful results or not without carrying out its realization thanks to the proposed method. |
20192060 | Impact of the Japanese diagnosis procedure combination-based payment system in Japan. | In the health insurance system of Japan, a fee-for-service system has been applied to individual treatment services since 1958. This system involves a structural problem of causing an increase in examination and drug administration. A flat-fee payment system called DPC was introduced in April 2003 to solve the problems of the fee-for-service system. Based on the data of 2003 and 2004, we assessed the impact of DPC in Japan, and obtained the following conclusions: First, the introduction of DPC in Japan could not decrease the absolute value of medical costs; second, the internal efficiency of the institutions was improved, for example, by reducing the mean length of hospitalizations; third, the DPC-based diagnosis classification is considered to be effective for simplifying the medical fee system within the framework of EBM and for providing patients with information; and fourth, after introduction of the DPC, structural problems remain in the flat-fee payment system, such as examination and treatment of low quality, selection of patients and up coding. Its introduction should thus be performed with sufficient caution. We will make greater efforts to establish a better medical fee system by evaluating these problems. |
20192061 | Preparations enable children's EDs to effectively handle H1N1 surge. | Tabletop exercises can be an effective strategy preparing for situations that involve numerous hospital departments, such as a pandemic surge. Here are some highlights of the successful tabletop exercises used by the Minneapolis and St. Paul EDs of Children's Hospitals and Clinics of Minnesota to prepare for last fall's H1N1 outbreak. Every unit that interfaces with the ED was involved in the discussions. Participants were given "homework assignments" to outline their role in the overall response process. Department heads made in-person visits to overflow spaces to ensure they had adequate resources should they be required to modate patients. |
20192062 | Are uninsured traumas at a greater risk? | While a new study indicating that uninsured trauma patients are at greater risk of mortality did not point a finger at EDs, experts say there are proactive steps ED managers can take that will help reduced the risk for these patients: Keep your eyes and ears open for any evidence of bias--where people express concerns about whether patients can pay for treatments. If a patient is on one or more medications, ask where they get the meds filled. With the patient's permission, call the pharmacy and get a list of all the meds he or she is taking. If language assistance is needed, ensure it's given. |
20192063 | Grant helps ED refer patients to health center. | With the help of a $2 million grant from the Centers for Medicare & Medicaid Services, the ED at Monmouth (NJ) Medical Center, and the Monmouth Family Health Center have created a referral system that had lightened the burden for the ED and found many more patients a health care "home." Whereas in the past, length of stay (LOS) for those patients who went to the fast track has been as high as 90 minutes, the LOS for these patients has been under 70 minutes. A puter system enables the ED to access the center's schedule and arrange for follow-up visits. The ED added 12 hours a day of advanced practice nurses during the busiest hours of the day to treat and refer uninsured patients. A primary care-type conditions list is used during triage to help identify referral prospects. |
20192065 | 'Split flow' slashes statistics for LWT, LOS. | A "split flow" program in the ED at Baptist Medical Center in San Antonio not only has slashed the left-without-treatment (LWT) rate from a high of 9.5% in spring 2009 to 2.2% at present, but it dramatically has improved patient satisfaction rates as well. An Emergency Severity Index (ESI) score determines which of the two areas is most appropriate for the patient. The "intake" area has an additional physician assistant or nurse practitioner for the 12 peak hours of each day. There is always a tech in triage in the event the nurse is required to leave the area. |
20192066 | ED was well prepared for no-diversion law. | When the state legislature gives you four-months' notice of passage of a no-diversion law, it's impossible to get ready in time, unless you've been working for several years on improving flow in your ED. The new triage process at Massachusetts General Hospital hit its stride just in time, and other departments made changes as well. The new triage process includes having an attending out front 12 hours a day, a resident in screening eight to 10 hours a day, and a nurse practitioner working 12 hours a day. A satellite lab operates in the ED on a 24/7 basis. A radiology attending is provided to the ED on a round-the-clock basis. |
20192067 | [NK cells, chemokines and chemokine receptors]. | NK cells are an ponent of natural immunity, which provides a defence response against viruses, bacterial and parasitic intracellular pathogens and tumour cells. NK cells are capable of rapid responses without prior sensitization and cytotoxic response is independent of the presence of the antigens of the major patibility system. NK cells produce a number of cytokines (e.g. INF-gamma, GM-CSF and TNF-beta) and chemokines and in this way they regulate both the natural and acquired immune response. By contrast, NK cells are regulated both positively and negatively by cytokines and chemokines produced by other immune cells. Attention is focused on the possibility of influencing the tumour process by using cytokine- and chemokine-activated NK cells. In studies in mice models as well as in several clinical trials, it has been shown that the presence of cytotoxic cells in tumour stroma is associated with a more favourable prognosis of cancer.There is also plenty of evidence that in tumour stroma a number of cytokines and chemokines are produced which may have ambivalent effects. |
20192068 | [New views of modern medicine regarding treatment with stem cells, its practical and ethical consequences]. | Embryonic stem (ES) cells recently became the Holy Grail for the treatment of multiple diseases including cancer. A recent discovery of Israeli scientists however shows that ES cells can also e one of the causes triggering cancer. They base this hypothesis on a case of an Israeli boy suffering from Ataxia teleangiectasia, who developed cancer 4 years after ES transplantation. DNA analysis of the tumors showed that the malignant cells originated from the transplanted ES cells of the donors and not from the recipient's own cells. Given the fact that the therapeutic application of ES cells is still in the beginning, it is therefore necessary to thoroughly verify and test all the risks of their potential therapeutic use. This article also discusses in detail ethical and other aspects of ES cells applications, in particular the differences in points of view between Christianity and Judaism. Israeli Health to address these issues draws on traditional Judaism. Judaism defines an individual as a man if he cans a separate existence, parison with the human embryo, which is still directly dependent on his or her mother. Therefore, in matters of saving lives, including treatment options for improving the living, treatment with ES cells is tolerated Judaism as a clear preference for live and self-sustaining individual, before a cluster of cells. On the other hand, it is clear that all these therapies must have their basic rules and ethical reasons. In Israel, research on ESC and allowed it to those obtained in the course of unsuccessful fertility treatment by artificial insemination. |
20192069 | [Angiogenesis as part of the tumor "ecosystem" and possibilities to influence it]. | Angiogenesis is plex process which is critical for the growth, invasion and metastasis of tumors. In the past ten years numerous new agents have been developed as angiogenesis inhibitors. In the review, angiogenesis inhibitors are classified by their targeted area of the angiogenic process. The role of VEGF and its receptors is described in detail, but other antiangiogenic strategies such as inhibition of endothelial proliferation, inhibition of matrix metalloproteinases and use of vascular disrupting agents are also reviewed. |
20192070 | [Very small breast cancer, HER2 positive, and trastuzumab in adjuvant treatment]. | Breast cancer patients with a tumor size of < or = 1 cm are still rare but their number is increasing as a consequence of mammary screening. It is logical that the best adjuvant treatment in such cancers is often discussed with respect to the risk of relapse of the disease. The number of patients in clinical trials with very small breast cancer is quite low, and a specific clinical trial for such patients is not planned. Retrospective analysis of some clinical trials which included patients with breast cancer and with very small size shows the worse prognosis of patients with HER2 positive tumors. Indirectly, we can assume the application of adjuvant treatment with trastuzumab in such very small breast cancer. However, the decision should be individual with regards to further risk factors for the disease and risk of the treatment itself. This article is more a contemplation in order to provoke discussion on this provocative subject. |
20192071 | [Demonstration of the effect of estrogen and progesterone receptors on survival in breast cancer without cytostatic and hormonal treatment in a small set of patients]. | With respect to diagnostic and therapeutic progress, it may occur that the statistical sets of patients evaluated and treated with uniform methods are small. As a consequence, it is meaningful to check a greater number of statistical approaches. It is suitable to verify whether, for instance, the differences between the results (+) and (++) for estrogen and progesterone receptors (ER and PR) in breast cancer have an effect on the length of survival. This question could be answered with the use of several Kaplan-Meier survival curves. However, it is also profitable to judge the simple graph of survival in dependence on receptor concentration. Nevertheless, traditional regression brings too great an error to this method of assessment. Therefore, the use of orthogonal regression is much more precise. Since it can be assumed that no non-revealable micro-metastases were present at the time of operation in some patients with N0, it is possible to achieve healing ad integrum of them using only simple surgery. Consequently, we concluded that it was necessary to exclude from the evaluation the group of patients in N0 surviving 10 years (in the search for evidence of the post-operative impact of age-based reduction of blood estrogen on survival). |
20192072 | Long-term outcome of treatment for Hodgkin's disease: the University Hospital Sofia experience. | To establish the efficacy of bined modality treatment (CMT) including curative extended field radiotherapy (EFRT) and chemotherapy (CHT) by examining the long-term e in Hodgkin's disease (HD) patients at the Sofia University Hospital "Queen Giovanna-ISUL", with particular focus on second primary malignancy (SPM), and to establish independent factors correlated with treatment e. |
20192074 | [Long-term response of liver metastases of breast cancer to capecitabine--case report]. | A case report of a patient with HER2-positive liver metastases of breast cancer. Partial regression was reached during chemotherapy, which was further stabilized by trastuzumab. Resection of the metastases was performed after progression. Capecitabine was started after the occurrence of new multiple plete regression was reached, which has now lasted over three years with continued capecitabine treatment. |
20192073 | Small-cell carcinoma of the ovary with breast metastases: a case report. | Small cell carcinoma (SCC) is characterised by high metastatic potential and the possibility to metastasize to practically any tissue. Small cell carcinoma of the ovary (SCCO) has a very poor prognosis and patients usually die within one year of the initial diagnosis. Breast metastases from SCCO are extremely rare. |
20192084 | The states go marching in. With an impasse in Washington, some states are taking sides in the reform debate. | With reform apparently sitting on the back burner in Washington, some states are cooking up their own healthcare policies-some of which are designed to slice and dice any federal initiatives. "We're different from Washington, D.C.," said Mark Leno, a state senator for California. "There, Congress has the final word. In California, the voters have the final word". |
20192092 | Tourniquet failure during total knee replacement due to arterial calcification: case report and review of the literature. | Use of a tourniquet for performing surgery in order to create a bloodless surgical field and reduce blood loss has been in use for many years. Tourniquets may fail perioperatively for various reasons, leading to ongoing bleeding. An important cause of tourniquet failure is calcification of the underlying artery. A patient undergoing total knee replacement surgery in whom the tourniquet failed, secondary to femoral artery calcification is reported. The implications of tourniquet use in patients with arterial calcification, including acute distal ischaemia, aneurysm formation and vessel fracture will be discussed. mendations include: thorough vascular assessment of all patients preoperatively, awareness of the possibility of tourniquet failure particularly in vasculopaths, and the provision of an alternative perioperative management plan such as use of a cell saver device, should the tourniquet fail. |
20192093 | Pain management in recovery. | Recovery room practitioners lay the corner stone for postoperative recuperation in patients undergoing surgical procedures. This article highlights how some aspects of the role, such as pain mencement of the prescribed analgesic regimen and pain control can be very challenging, for a variety of reasons. The aim, therefore, is to follow a typical patient journey in a structured manner, beginning with a demonstration of how provision of information empowers patients during the key phase of postoperative recovery. This is followed by a description of some assessment tools best suited to patients recovering from anaesthesia who are experiencing acute, postoperative pain. Consequences of under-treated pain are discussed and treatment modalities are described. |
20192094 | The monitoring of heparin induced thrombocytopenia following surgery: an audit and international survey. | Heparin-induced thrombocytopenia (HIT) is a serious plication of low-molecular-weight heparin (LWMH) prescribed following surgery and recent evidence based guidelines mend routine platelet count monitoring for all at-risk patients. With the implementation of these guidelines this clinical study demonstrated a significant improvement (2-56% p < 0.05) in HIT diagnosis in postoperative patients receiving LMWH. An international survey showed a lack of awareness of heparin-induced thrombocytopenia and its management. |
20192098 | Why nursing research in tobacco control? | Tobacco use is an epidemic of overwhelming proportions affecting survival, causing millions of deaths every year, causing untold human suffering worldwide, and contributing to escalating health care costs. Nursing research is vital to advancing knowledge in the field and to the translation of science to evidence-based practice. As the largest group of health care professionals (17 million worldwide), nurses have the capacity for an enormous impact on this leading cause of preventable death. This chapter thus provides a historical overview of the tobacco epidemic, health risks of smoking and benefits of quitting, nicotine addiction, and mendations of evidence-based tobacco dependence treatment as a backdrop for understanding the importance and need for nursing scholarship. Also examined are nursing science efforts and leadership in removing two barriers to mounting programs of nursing research in tobacco control: (1) lack of nursing education and training in tobacco control, and (2) limited research funding and mentorship. The chapter also addresses the issue of smoking in the profession as it impacts nurses' health, clinical practice, and, potentially, scholarship efforts. |
20192099 | Theories used in nursing research on smoking cessation. | Theories tell how and why things work; how and why one variable is related to another. Research findings that are theory based can be placed in a framework that advances science further than findings that are unconnected to formal theory. However, much of the research in smoking cessation is atheoretical. This review of nursing research on smoking cessation published from 1989 through 2008 revealed that nearly half of the studies were based on explicit formal theories. The transtheoretical model and self-efficacy theory were the most frequently used explicit theories with most theories emanating from psychology. Five nursing theories were identified in this review. Studies that used implicit rather than explicit theories dealt with five major concepts: nicotine dependence, social support, high-risk situations, mood-affect, and the influence of clinical diagnosis. Largely missing from this set of studies were investigations based on biobehavioral models, including genetics and neuroscience. The relevance of the theories and concepts identified in this review to current clinical guidelines on smoking cessation is discussed. With their grounding in theory and their expert knowledge of clinical issues, nurses are in an excellent position to develop theories that will help researchers in every discipline make sense of smoking cessation. |
20192100 | The social and political context of the tobacco epidemic: nursing research and scholarship on the tobacco industry. | Context matters in addressing tobacco as a global nursing issue. The tobacco epidemic and its resulting health consequences are in great measure the result of industrial decisions over the past century that included deliberately enhancing the addictiveness of cigarettes, marketing them aggressively to vulnerable groups, hiding or manipulating knowledge about the products' harmfulness, and undermining public health efforts. The efforts of the tobacco industry to perpetuate the idea that smoking is solely a problem of individual behavior, or even a "right," still creates barriers to understanding the larger social and political context within which individuals use and attempt to quit tobacco. Nurses have been among the researchers worldwide who are studying tobacco industry activities and their role in policy and public health. This chapter reviews data sources, methods, and analytic approaches for conducting research using documents from the tobacco industry, and provides an overview of research conducted by nurses on this topic. Much of the nursing research to date on the tobacco industry focuses in four broad areas: (1) tobacco industry influence on policy; (2) tobacco industry strategic responses to public health efforts, including use of front groups and attempts to divide and conquer public health advocates; (3) tobacco industry targeting of marginalized groups; and (4) tobacco industry influence on science. Implications of this work for nursing practice, research, and policy intervention are discussed. |
20192101 | Monitoring the tobacco epidemic with national, regional, and international databases and systematic reviews: evidence for nursing research and clinical decision making. | Tobacco use (primarily cigarette smoking) continues to be the most preventable health risk in the United States and the second greatest health threat around the world. In 2020 the global burden is expected to exceed nine million deaths annually. Nursing, with the largest numbers of health care professionals has an opportunity to make a significant reduction in tobacco use through its research and client-focused care. This chapter addresses why and how monitoring the tobacco epidemic with population-based databases and meta-analyses is important for nurse researchers and for evidence-based nursing practice. Population-based surveys permit an examination of trends in tobacco use and the progress in tobacco control with some confidence across time, places (i.e., states, munities, etc.), and large numbers of participants. Included in this review are a description of the numerous national and international databases and other resources that nurse researchers can use to build the science of tobacco use. Additionally, research reviews and meta-analyses are described as other vehicles for providing a basis for making evidence-based decisions about nursing intervention. Nurse scientists have an obligation to use and evaluate these diverse resources to determine the gaps in knowledge, provide a foundation for clinical practice, and identify the needs and directions for future research in the field. |
20192102 | Nurses' use of qualitative research approaches to investigate tobacco use and control. | Qualitative research methods are increasingly used by nurse scientists to explore a wide variety of topics relevant to practice and/or health policy issues. The purpose of this chapter is to review the contributions of nurse scientists to the field of tobacco control through the use of qualitative research methods. A systematic literature search strategy was used to identify 51 articles published between 1980 and 2008. The majority (84%) of reviewed articles were authored by North American nurse scientists. Cessation was the monly (85%) studied aspect of tobacco control. Six qualitative research approaches were used: qualitative descriptive (55%), narrative analysis (8%), phenomenology (6%), grounded theory (14%), ethnography (12%), and case study (6%). Qualitative descriptive methods were primarily one-off studies to address practical problems or issues encountered in practice, and often validated current understandings related to tobacco. Researchers who used other types of qualitative methods and who conducted qualitative studies as part of programs of research were more likely to make more substantive contributions to the evolving field of tobacco control. These contributions related to how smoking intertwines with personal and social identities, the influence of social context on tobacco use, and nurses' involvement in tobacco control (both of their own tobacco use and in assisting others). Nurse scientists interested in exploring tobacco-related issues are encouraged to consider the full range of qualitative research approaches. Qualitative research methods contribute to our understanding of tobacco use arising from nursing practice, health care and policy, along with the field of tobacco control in general. |
20192103 | Biological models for studying and assessing tobacco use. | The purpose of this chapter on biological models for studying and assessing tobacco use is to provide an introduction to some of mon concepts and biomarkers in this arena to ultimately inform intervention research by nurse scientists. An overview of selected biomarkers of tobacco exposure in individuals includes exhaled carbon monoxide, cotinine (the proximate metabolite of nicotine), and measurement of an individual's puffing pattern termed smoking topography. Common tobacco contents discussed include tobacco specific nitrosamines (TSNA) and polycyclic aromatic hydrocarbons (PAH) some of which increase disease risk including cancer. Exemplars of additives to cigarettes by the tobacco industry will be described including menthol, one additive marketed by the industry. Genetics and tobacco addiction has emerged as a rapidly expanding field. Illustrative of this area are twin studies, nicotinic receptors, CYP2A6 polymorphisms, and genes that impact dopamine receptors. The cadre of nurse scientists conducting research in this much needed area is small. The opportunity for nurse scientists educated in biological inquiry in tobacco-related research is great. Nurse scientists actively involved in multidisciplinary translational teams to address nicotine addition are needed. |
20192104 | Primary and secondary tobacco prevention in youth. | The childhood years represent a critical time for tobacco experimentation and addiction. This chapter presents risk factors for youth smoking, state of the science of nurse-led primary and secondary tobacco prevention research in youth, and implications for future research, policy, and practice. Nursing research on both primary and secondary tobacco prevention efforts that are school-based, family-based, munity-based are presented. Interventions, including both state munity approaches, and media and policy endeavors to prevent tobacco use and foster successful cessation are discussed. The nursing profession has made an impact on primary and secondary prevention in youth regarding tobacco; however, much remains to be plished. As one of the largest health care professions, nurses should seize the important opportunity of positively impacting the health of children and youth prehensive and effective primary and secondary tobacco prevention efforts. |
20192105 | Two decades of nurse-led research on smoking during pregnancy and postpartum: concept development to intervention trials. | Tobacco use during pregnancy and postpartum is a leading cause of preventable morbidities for women and their infants. Over the past two decades, nursing research has addressed this recalcitrant clinical problem from a variety of conceptual and methodological perspectives. The 64 published studies (1988-2009) that met inclusion criteria for this systematic review represent the full research trajectory from concept development to intervention testing. Meta-analysis demonstrated an overall significant trend in nursing intervention efficacy (OR = 1.14, 95% CI = 1.08-1.2) for studies that parable prenatal and postpartum smoking cessation es. Implications for future nursing research and evidence-based policy are presented. |
20192106 | Nursing interventions in tobacco-dependent patients with cardiovascular diseases. | Smoking is a well-established risk factor for cardiovascular disease (CVD). This chapter provides an overview of a program of nursing research relevant to tobacco use in patients with CVD. The Women's Initiative for Nonsmoking (WINS) provides a rich demonstration of a key randomized clinical trial (RCT) on the efficacy of smoking cessation in women. The National Institutes of Health priority for data mining of existing RCTs is demonstrated in the numerous presentations of findings from secondary papers from WINS that answer additional research questions relevant to smoking cessation, including the influence of depression on smoking, myths about and underuse of nicotine replacement therapy. The methodological and logistical challenges inherent in tobacco intervention studies are presented, including a discussion of research needed in the measurement of withdrawal symptoms. Additionally, the role and contributions of nurses serving on the federal guideline development process are highlighted. International research activities of the coauthors from Jordan and Korea are also presented, including a discussion of the need for research in waterpipe use. |
20192108 | Evidence-based smoking cessation interventions for patients with acute respiratory disorders. | Worldwide, tobacco use continues to be the most significant preventable cause of death and hospital admissions, particularly related to respiratory diseases. Acute respiratory illnesses requiring hospitalization provide an opportunity for nurses to intervene and help smokers quit. Of the three top hospital admissions related to respiratory diseases, chronic obstructive pulmonary disease (COPD) is the one that continues to have increased mortality munity acquired pneumonia and asthma have decreased over the past 5 years. The course of all three can be caused or exacerbated by continued smoking. This review describes the state of the science of nursing research focused on tobacco cessation interventions for hospitalized patients with COPD, asthma, munity acquired pneumonia. Additionally, we describe two evidence-based, nurse-driven, hospital protocols to treat tobacco dependence that can serve as models of care. mendations are made as to how to effectively promote nursing interventions for tobacco cessation in the acute care setting. |
20192107 | Smoking cessation interventions in cancer care: opportunities for oncology nurses and nurse scientists. | Smoking cessation is essential after the diagnosis of cancer to improve clinical es. The purpose of this chapter is to provide a systematic review of research on smoking cessation in the context of cancer care with an emphasis on nursing contributions to the field. Data sources included research reports of smoking cessation interventions conducted in people with cancer. Nineteen primary studies were reviewed. High intensity interventions, targeting multiple behaviors, and/or using a ponent intervention that included pharmacotherapy, behavioral counseling, and social support were characteristics of the most successful treatments for tobacco dependence. The majority of interventions were conducted in adults with smoking-related malignancies during acute phases of illness. The most striking finding was that more than one half of the studies tested the efficacy of nurse-delivered interventions. Conceptual and methodological issues that can be improved in future studies include: using theoretical frameworks to specify how the intervention will affect es, ensuring adequate sample sizes, using biochemical verification to monitor smoking es, and using standardized e measures of abstinence. Although effective interventions are available for healthy populations, further research is needed to determine if tailored cessation interventions are needed for patients with cancer. To provide optimal quality care it is imperative that delivery of evidence-based smoking cessation interventions be integrated into the cancer treatment trajectory. Multiple barriers, including patient and nurse attitudes toward smoking and lack of knowledge related to tobacco treatment, prevent translating evidence-based tobacco dependence treatment into clinical practice. Further nursing research is needed to address these barriers. |
20192109 | A review of research by nurses regarding tobacco dependence and mental health. | The prevalence of tobacco use and dependence among those with psychiatric and/or substance use disorders is exceptionally high, contributing to significant morbidity and mortality. The purpose of this review is to discuss the findings conducted by nurses regarding smoking and mental health. A search of the available literature since 1950 resulted in a review of 17 studies authored or coauthored by nurses. Most study designs were descriptive with only one investigator reporting the results of a small clinical trial. In addition to documenting smoking patterns in this population, investigators found that many psychiatric nurses assessed their clients for tobacco use and advised them to stop smoking but few intervened intensively to aid cessation. Psychiatric nurses reported low efficacy for delivering interventions and considerable doubt about their clients' abilities and motivation to stop smoking. Although some desired additional training in tobacco dependence interventions, nurses reported feeling ethically conflicted about, and were inconsistently supportive of, system level interventions such as tobacco free health care settings. It is likely that these findings, as well as the paucity of tobacco dependence studies, reflect the relatively small number of psychiatric nurses conducting research as well as the inattention, until recently, of mental health leaders, policy makers, and funders to the importance of tobacco dependence research in this clinical population. As tobacco dependence treatment for those with mental illnesses and/or addictive disorders es more of a public health priority, opportunities abound for nurse researchers to contribute to the growing evidence in this often neglected area. |
20192110 | Nursing research in tobacco use and special populations. | Smoking is responsible for approximately one in five deaths in the United States per year. The Surgeon General's 1964 report first linked smoking as a cause of cancer. Since then cigarette smoking has had a steady decline to its current estimate of 19.8%. There are, however, some special populations where smoking continues to occur at a higher prevalence than the general population. This chapter discusses tobacco dependence among the following special populations: low socioeconomic status including Medicaid, hard-core smokers, rural, and homeless; immigrants; and persons living with HIV. For each population, there is an overview of the disparities in tobacco use, special challenges unique to that population, and exploration of current research on tailoring of tobacco dependence treatment. Each of the special populations discussed present unique challenges with tobacco dependence treatment that will require careful examination before disparities will ultimately decrease. Eliminating disparities has been marked as an important research agenda item as noted in Healthy People 2010. Nurse researchers are well positioned bine their clinical expertise and knowledge of patient psychosocial needs with investigation of patient-focused research questions in each of these special populations. |
20192111 | Systems approaches to tobacco dependence treatment. | Nurses have been at the forefront of initiatives to improve patient es through systems change. Nursing research addressing systems approaches to treatment of tobacco dependence has demonstrated increased implementation of evidence-based practice guidelines. Existing health system research conducted by nurse scientists has focused on four strategies: tobacco use identification systems, education and training of nursing staff to deliver tobacco intervention, dedicated staff for tobacco dependence treatment in both acute and primary care settings, and institutional policies to support tobacco intervention. Nursing involvement in multidisciplinary health services research focusing on tobacco treatment has lagged behind advances in clinical nursing research of individual-focused smoking cessation interventions. Health information technology shows promise as part of an integrated approach to systems changes to support tobacco intervention, particularly in light of the current national emphasis on adoption and meaningful use of electronic health records. Future directions for translational research present unprecedented opportunity for nurse scientists to respond to the call for policy and systems changes to support tobacco treatment. |
20192113 | Opportunities for nursing research in tobacco control. | Nurse scientists have made important contributions to evidence-based practice in tobacco control. This chapter will discuss recent tobacco control developments in the United States and globally, such as legislation giving the U.S. Food and Drug Administration regulatory authority over tobacco products manufacturing, marketing and sales, the World Health Organization Framework Convention on Tobacco Control, and a brief review of research that has guided policy advances and nursing research in tobacco control. Suggestions for future research based on the update of the U.S. Public Health Services Treating Tobacco Use and Dependence clinical practice guideline will be explored. These developments offer nursing researchers a wealth of opportunities and challenges to advance nursing and tobacco control knowledge, address research gaps, and bring a unique nursing perspective to tobacco use prevention, reduction of exposure to secondhand smoke, tobacco dependence treatment, and tobacco control policies. Additionally, we will address how nursing scholarship can and should be supported by academic and organizational leadership to support nurses in realizing their full potential in mitigating the global epidemic of tobacco-caused death and disease. |
20192112 | Nursing research in community-based approaches to reduce exposure to secondhand smoke. | Secondhand smoke (SHS) is the third leading cause of preventable death in the United States and a major source of indoor air pollution, accounting for an estimated 53,000 deaths per year among nonsmokers. Secondhand smoke exposure varies by gender, race/ethnicity, and socioeconomic status. The most effective public health intervention to reduce SHS exposure is to implement and enforce smoke-free workplace policies that protect entire populations including all workers regardless of occupation, race/ethnicity, gender, age, and socioeconomic status. This chapter munity and population-based nursing research to reduce SHS exposure. Most of the nursing research in this area has been policy e studies, documenting improvement in indoor air quality, worker's health, public opinion, and reduction in Emergency Department visits for asthma, acute myocardial infarction among women, and adult smoking prevalence. These findings suggest a differential health effect by strength of law. Further, smoke-free laws do not harm business or employee turnover, nor are revenues from charitable gaming affected. Additionally, smoke-free laws may eventually have a positive effect on cessation among adults. There is emerging nursing science exploring the link between SHS exposure to nicotine and tobacco dependence, suggesting one reason that SHS reduction is a quit smoking strategy. Other nursing research studies munity readiness for smoke-free policy, and examine factors that build capacity for smoke-free policy. Emerging trends in the field include tobacco free health care and college campuses. A growing body of nursing research provides an excellent opportunity to conduct and participate munity and population-based research to reduce SHS exposure for both vulnerable populations and society at large. |
20192114 | Interstitial infusion of erlotinib in the rodent brain. | A critical need exists for the development of novel forms of treatment for high-grade glioma. Molecular characterization of high-grade glioma has shown overexpression of the epidermal growth factor receptor, antagonists to which, including erlotinib, may prevent tumor growth. Interstitial infusion is a mode of local delivery which bypasses the blood-brain barrier and utilizes a pressure-dependent gradient to enhance drug uniformity and volume of distribution. Interstitial infusion of erlotinib was performed to the striatum of 12 rats in increasing, therapeutic doses. No evidence of clinical or histopathologic toxicity was found. In this experimental study we demonstrate that interstitial infusion of erlotinib is safe in the rodent brain, and may have potential applicability for the treatment of high-grade glioma. |
20192115 | Vinblastine-induced ultrastructural transition of microtubular scaffoldings in the SV40-transformed 3T3 murine fibroblasts. | SV40-transformed 3T3 cells (SV3T3) treated with the antitubulin chemotherapeutic agent vinblastine exhibited ultrastructural alterations in their cellular microtubular scaffolding by electron microscopy. Apparent disappearance of the subcellular microtubules occurred after the cells were incubated with vinblastine at 10 microg/ml at 37 degrees C for 8 hours. Typical cytoplasmic microtubular crystals were found with additional smooth membrane-limited vesicles. These vesicles mimic the differentiation cellular organelle called annulated lamellae. Microtubules were frequently seen associated with the Golgi apparatus and rough endoplasmic reticulum in the SV3T3 cells. These microtubules may contribute to transport of products between the Golgi and the rough endoplasmic reticulum. When treated with vinblastine, microtubular crystals were also observed between the Golgi and the rough endoplasmic reticulum. The size and numbers of cytoplasmic inclusions were increased in vinblastine-treated cells. In the SV3T3 cells, microtubules are determined by image analysis to be 230 A degrees in diameter with a subunit wall of 45 A degrees thick. These microtubules have a center-to-center space of 55.6 A degrees between the protofilaments. The skewed heterodimeric microtubular subunits posed of disk-like structures of 45 A degrees in length, 30 A degrees in width, and 20 A degrees in thickness. The subunit center-to-center skewed angle is 40 degree. After the cells were treated with vinblastine, the microtubules undergo a transitional dissociation, and reassemble into ordered crystals. These transitional microtubules have an increased diameter of 350 A degrees, and a larger protofilament center-to-center space of 85 A degrees. These morphometric measurements indicated that there is a critical microtubule dissociation distance of 30 A degrees, exceeded which the typical microtubular ultrastructure may no longer exist. |
20192116 | Study of in vitro and in vivo effect of docosahexaenoic acid on rat C6 glioma. | Docosahexaenoic acid (DHA) may have potential anticarcinogenic effect. In the present study, effect of DHA on rat C6 glioma was tested. In vitro, cytotoxic effect of 50-400 microM DHA on C6 cells was evaluated pared with linoleic acid (LA). In vivo, adult female Wistar rats implanted with C6 tumor, fed 1 ml of DHA oil (containing 73% DHA, 36 rats) or LA oil (containing 72-77% LA, 41 rats) daily, starting one week prior to tumor implantation until death or if survived, until 30 days after implantation. Another group of tumor bearing rats was treated with chloroethyl-cyclohexyl-nitrosourea (CCNU, 30 mg/kg, 31 rats) at day 8 post implantation to show if the result of oil supplementation parable to single agent chemotherapy. mRNA expression of p21 and p27 was determined in vitro at 100 and 150 microM of fatty acids and in tumors of rats supplemented with LA or DHA oils. In vitro, DHA, but not LA, had cytotoxic effect on C6 cells at 200 and 400 microM and DHA increased mRNA expression of p21 at 150 microM (p < 0.05). In rat glioma model, although a non-significant trend towards better survival was observed in DHA oil relative to LA oil group, the difference was not significant (p = 0.20). p21 and p27 mRNA expression in tumors of DHA oil group did not differ with LA oil group. Single dose of CCNU increased survival pared to LA oil group (p < 0.001). In conclusion, intake of DHA at the dose or duration employed in the present study might be insufficient to bring about its cytotoxic action on rat's C6 brain tumor. |
20192117 | Anticancer drugs exert differential apoptotic and cytotoxic effects on glioblastoma primary cultures with various EGFR and bcl-2 profiles. | The aim of this study was to determine the apoptotic and cytotoxic effects induced on glioblastoma cells by various anticancer agents that possess different mechanisms of action (alkylating drugs, anti-EGFR (Epidermal Growth Factor receptor), proteasome inhibitor). Primary cell cultures were obtained from patients who underwent surgery for their glioblastoma. The cytotoxic effects of drugs were determined by MTT (dimethylthiazolyl diphenyl tetrazolium bromide) assay and apoptosis was evaluated by measuring mitochondrial potential by flow cytometry. Biological markers (EGFR, bcl-2) were studied by a immunoblotting technique to find out predictive markers of response. We found a large interindividual sensitivity, thus confirming the interest of the primary cultures. New proteasome inhibitor bortezomib had considerable cytotoxic and apoptotic potential in glioblastoma, even at very low concentrations. Moreover, the characterization of patients' cells for EGFR and bcl-2 status could constitute an interest, with the evaluation of other markers, in the study of expected chemotherapy response. |
20192118 | Therapeutic suppression of constitutive and inducible JAK\STAT activation in head and neck squamous cell carcinoma. | The oncogenic role of STAT3 has been elucidated in a number of human malignancies including leukemia, lymphoma, malignant glioma and cancers of the breast, lung, and head and neck (HNSCC). Here we show that WP1066 has profound anti-neoplastic effects in HNSCC, mediated in part by suppression of JAK2-STAT3 signaling. WP1066 inhibited constitutive and inducible STAT3 phosphorylation in both dose- and time-dependant manners. Further, the nuclear translocation of STAT3 pletely inhibited, resulting in decreased DNA binding activity. In vivo testing of WP1066 in a nude mouse orthotopic model of HNSCC demonstrated significant anti-tumor effects, with histological evidence of decreased cellular proliferation and angiogenesis. Collectively, these data suggest that WP1066 suppresses squamous cell carcinoma cell growth, in part through its effects on JAK-STAT pathways, and establishes this small molecule as potentially efficacious agent in the treatment of HNSCC. |
20192120 | Superselective intraarterial cerebral infusion of bevacizumab: a revival of interventional neuro-oncology for malignant glioma. | Glioblastoma Multiforme (GBM) is a uniformly fatal disease with a median survival of approximately 15 months. Recent monoclonal antibody therapies such as Bevacizumab (Avastin) have been shown to be active in GBM and to prolong survival in patients with recurrent malignant glioma. Therefore, patients routinely receive intravenous (i.v.) Bevacizumab (10 mg/kg) every two weeks when they have recurred following standard therapy with chemoradiation. I.v Bevacizumab; however, can cause significant systemic side effects including bowel perforation and pulmonary embolism. In addition, the blood brain barrier (BBB) continues to provide an obstacle to the effective delivery of the antibody to the brain tumor bed. In order to e the BBB, and to limit the systemic toxicity of i.v. Bevacizumab, we have begun a Phase I clinical trial to test the safety of transient blood brain barrier disruption with intraarterial (IA) Mannitol followed by superselective intraarterial cerebral infusion (SIACI) of Bevacizumab. This case report describes the technical aspects of this procedure and its associated benefits and risks. This novel delivery method, which may herald the revival of Interventional Neuro-oncology, may significantly alter the way therapy is administered to patients with GBM. |
20192121 | P-170 peptides with low similarity to the human proteome: tracing an effective and safe biological way towards effective and safe cancer chemotherapy. | We propose low-similarity P-170 peptide-based antibodies to neutralize the multidrug resistance phenomenon and, consequently, improve the treatment regimens for cancer chemotherapy. As a first step in the experimental validation of this approach, we report on the similarity analysis of the P-170 primary amino acid structure versus the human proteome and describe peptide motifs uniquely owned by the human P-170 glycoprotein. |
20192122 | Reactive oxygen species, especially O2+* in cancer mechanisms. | In the nature including the human organism there are 5 reactive oxygen species (ROS): O2, O2-*, O2+*, 1O2, O3 with different electromagnetic characteristics and biological effects. The effects of enrichment of medical oxygen O2 with traces of ROS on various cells were tested in experiments. |
20192119 | Inhibition of BCL2 expression and activity increases H460 sensitivity to the growth inhibitory effects of polyphenon E. | The anti-cancer properties of the green tea-derived mixture Polyphenon E (Poly E) have been demonstrated in a variety of cell culture and animal models. We recently discovered that the H460 lung cancer cell line is markedly resistant to the growth inhibitory effects of Poly pared with SW480 colon and Flo-1 esophageal cancer cells. We investigated the mechanism of H460 resistance paring gene expression profiles of Poly E-sensitive and -resistant cells. Unsupervised hierarchical clustering revealed that Poly E-sensitive cells clustered separately from Poly E-resistant cells, and 6,242 genes were differentially expressed between the two groups at the 0.01 level of significance. We discovered that BCL2 gene and protein expression were significantly higher in H460 pared with SW480 and Flo-1 cells (10.60-fold higher gene expression; P < 0.0001). Inhibition of BCL2 expression and activity, using siRNA and the small molecule inhibitor HA14-1 respectively, restored sensitivity to Poly E and induced BCL2-related apoptosis by decreasing mitochondrial membrane potential and inducing PARP cleavage. Our results suggest that increased BCL2 expression may contribute to H460 resistance to the growth inhibitory effects of Poly E. If validated in additional laboratory and clinical models, BCL2 could ultimately be used as a marker of Poly E resistance. |
20192123 | Susceptibility of colorectal cancer cells to Sindbis virus infection. | Sindbis virus (SIN), a member of the Togaviridae family, infects a broad range of cells and has been shown to be an effective anti-tumor agent. The infection efficiency of the virus, however, varies greatly among target cells. In this report, pared the ability of SIN to infect colorectal cancer cells and cells of other cancer origin. While tumor cells from breast, leukemia, and prostate cancers were largely resistant to SIN infection, nine of the ten colorectal cancer cell lines tested were sensitive to SIN infection. Moreover, SIN susceptibility correlated with the metastatic potential of the colorectal cancer cells. Two highly aggressive and invasive cell lines, SW620 and COLO-320DM were the most sensitive to SIN infection. Similarly, SIN preferentially targeted metastatic tumor cells in a mouse xenograft model for colon cancer progression. The higher infection rate was not due to increased expression of the 67kD laminin receptor, a specific receptor for SIN infection, although viral attachment and entry were markedly enhanced in SW620 cells. These results suggest that SIN may employ a novel cell attachment/entry mechanism during infection, allowing selective targeting of colorectal cancer cells. |
20192125 | Preserved striate cortex is not sufficient to support the McCollough effect: evidence from two patients with cerebral achromatopsia. | The McCollough effect (ME) is a colour aftereffect contingent on pattern orientation. This effect is generally thought to be mediated by primary visual cortex (V1) although this has remained the subject of some debate. To determine whether V1 is in fact sufficient to subserve the ME, pared McCollough adaptation in controls to adaptation in two patients with damage to ventrotemporal cortex, resulting in achromatopsia, but who have spared V1. Each of these patients has some residual colour abilities of which he is unaware. Participants performed a 2AFC orientation-discrimination task for pairs of oblique and vertical/horizontal gratings both before and after adaptation to red/green oblique induction gratings. Successful ME induction would manifest itself as an improvement in oblique-orientation discrimination owing to the additional colour cue after adaptation. Indeed, in controls oblique grating discrimination improved post-adaptation. Further, a subdivision of our control group demonstrated successful ME induction despite a lack of conscious awareness of the added colour cue, indicating that conscious colour awareness is not required for ME induction. The patients, however, did not show improvement in oblique-orientation discrimination, indicating a lack of ME induction. This suggests that V1 must be connected to higher cortical colour areas to drive ME induction. |
20192126 | Facilitation of responses to degraded targets by non-degraded distractors. | It is well-established that distractors interfere with goal-directed responses. Our recent findings indicate that the presence of corners in degraded line drawings of distractor stimuli modulates response times and accuracy to non-degraded targets (Kritikos and Pavlis 2007, Experimental Brain Research 183 159-170). In the present study we asked whether non-degraded distractors may facilitate responses to degraded targets (corners or line segments missing). We presented targets at fixation and panied by identical, category-congruent, or category-incongruent distractors. Participants responded to two object categories (musical instruments and tools) consisting of four line drawings. Corners-missing targets in particular were associated with greater interference from distractors than non-degraded targets. This interference was modulated when distractor locations were endogenously or exogenously cued. Findings are discussed in the context of additional processing of object features that are crucial to action. |
20192127 | Perception of parallelepipeds: Perkins's law. | Two experiments were carried out to study the perception of parallelepipeds. In the first, the subjects were shown images of parallelepipeds and were asked to judge the 3-D orientations of the faces of the parallelepipeds, as well as the shapes of the faces. These two types of judgments were found to be inconsistent. Specifically, the parallelepipeds reconstructed from judgments of 3-D orientations of the faces were systematically different from the parallelepipeds reconstructed from judgments of the shape of the faces. In the second experiment, the subjects were asked to choose which reconstruction was closer to their percept. In most trials the subjects chose the 3-D parallelepiped reconstructed from judgments of the shapes of the faces. These results suggest that the percept of the shape of a 3-D object is not based on the judgments of the 3-D orientations of the object's surfaces. Instead, the 3-D shape percept is based on simplicity constraints. A putational model is presented, which generalizes Perkins's law (Perkins 1972). Instead of orthogonality, the new model uses mirror-symmetry and planarity constraints, in conjunction with maximum pactness and minimum surface-area constraints. The parallelepipeds recovered by the model are very close to the parallelepipeds perceived by the subjects. |
20192128 | Big people, little world: the body influences size perception. | Previous research has shown that changes to the body can influence the perception of distances in near space (Witt et al, 2005 Journal of Experimental Psychology: Human Perception and Performance 31 880-888). In this paper, we question whether changes to the body can also influence the perception of extents in extrapersonal space, namely the perception of aperture widths. In experiment 1, broad-shouldered participants visually estimated the size of apertures to be smaller than narrow-shouldered participants. In experiment 2, we questioned whether changes to the body, which included holding a large object, wearing a large object, or simply holding out the arms would influence perceived width. Surprisingly, we found that only when participants' hands were widened was extrapersonal space rescaled. In experiment 3, we explored the boundaries of the effect observed in experiment 2 by asking participants to hold their arms at four different positions in order to determine the arm width at which apertures appeared smaller. We found that arm positions that were larger than the shoulder width made apertures appear smaller. The results suggest that dimensions of the body play a role in the scaling of environmental parameters in extrapersonal space. |
20192129 | Rubber hand illusions and size-weight illusions: self-representation modulates representation of external objects. | Bodily illusions offer an experimental method to investigate the origins and functional role of the sense of one's own body. Using the rubber hand illusion (RHI) we show that a representation of one's own body is implicitly used to calibrate perception of external objects. Twelve participants experienced the RHI while watching stimulation of a large or small glove simultaneously with stimulation of their own hand. They then grasped cylinders of identical size but varying weight. RHI with the large glove caused the cylinders to feel heavier. We suggest that an illusory increase in hand size made the subsequently grasped cylinder feel correspondingly small, evoking a size-weight illusion. Self-representation thus influenced exteroception. The sense of one's own body provides a fundamental reference for perception in general. |
20192130 | Specificity and coherence of body representations. | Bodily illusions differently affect body representations underlying perception and action. We investigated whether this task dependence reflects two distinct dimensions of embodiment: the sense of agency and the sense of the body as a coherent whole. In experiment 1 the sense of agency was manipulated paring active versus passive movements during the induction phase in a video rubber hand illusion (vRHI) setup. After induction, proprioceptive biases were measured both by perceptual judgments of hand position, as well as by measuring end-point accuracy of subjects' active pointing movements to an external object with the affected hand. The results showed, first, that the vRHI is largely perceptual: passive perceptual localisation judgments were altered, but end-point accuracy of active pointing responses with the affected hand to an external object was unaffected. Second, within the perceptual judgments, there was a novel congruence effect, such that perceptual biases were larger following passive induction of vRHI than following active induction. There was a trend for the converse effect for pointing responses, with larger pointing bias following active induction. In experiment 2, we used the traditional RHI to investigate the coherence of body representation by synchronous stimulation of either matching or mismatching fingers on the rubber hand and the participant's own hand. Stimulation of matching fingers induced a local proprioceptive bias for only the stimulated finger, but did not affect the perceived shape of the hand as a whole. In contrast, stimulation of spatially mismatching fingers eliminated the RHI entirely. The present results show that (i) the sense of agency during illusion induction has specific effects, depending on whether we represent our body for perception or to guide action, and (ii) representations of specific body parts can be altered without affecting perception of the spatial configuration of the body as a whole. |
20192131 | Perception of 'best likeness' to highly familiar faces of self and friend. | We investigated the idea that our memory for familiar faces involves an accurate representation of their unique spatial configuration and, further, whether this configuration may be caricatured in memory. In separate experimental blocks, thirty-five Irish participants were presented with a series of photographic images of their own face and of the face of a close friend, and were asked to choose the image which looked most like themselves or their friend. Both sets of images included an original full-face colour photograph, and photographic distortions ranging from a highly caricatured (+100%) to a highly anti-caricatured (-100%) version of the original, generated with reference to newly created average male and female Irish faces. Contrary to suggestions that we hold a slightly caricatured version of a familiar face in memory, the mean 'best-likeness' image, calculated across both self and friend trials, was an anti-caricature of -13.88% which was significantly different from 0 (t69 = -5.34, p < 0.0001). The difference in the mean 'best-likeness' image chosen for self (-12.06%) and friend (-15.7%) was not significant (t34 = 0.715, p = 0.48). These results are discussed with reference to our ability to discriminate facial shape, together with the possibility that we idealise the attractiveness of faces of those close to us. |
20192132 | Revisiting the processing of internal and external features of unfamiliar faces: the headscarf effect. | Five experiments are reported in which the relative importance of internal and external features for unfamiliar face identification are examined by a matching task. In experiments 1-3, Egyptian adults showed a robust internal-feature advantage for matching photographs of Egyptian faces. In experiment 4, a parison between the ability of Egyptian and British adults to match the internal and external features of unfamiliar Egyptian and British faces was made. Once again, Egyptians showed an internal-feature advantage, for all faces. In contrast, British observers and also Egyptian children in experiment 5--showed external-feature advantages consistent with previous research. We attribute this contrast to the long-term experience of Egyptians in perceiving and recognising faces with headscarves, which might develop more expertise in processing the internal than the external features of unfamiliar faces. |
20192133 | Recognition of emotional expressions is affected by inversion and presentation time. | It has been repeatedly shown that face inversion affects the recognition of emotional faces. However, previous results are heterogeneous concerning the affected emotions and the influence of presentation time is unclear. We examined the impact of limited presentation time (200 ms) on the face-inversion effect during recognition of basic emotions in 128 healthy young adults. Data analysis revealed differential inversion effects for emotional expressions, further modified by limitation of presentation time: when presentation was limited, we observed inversion effects for angry and neutral faces which were absent in the unlimited trials. In the unlimited condition, inversion particularly affected recognition of disgust and sadness. No general inversion effect occurred for neutral expressions. Error analysis highlighted specific confusions for the inverted condition, except for happy and neutral expressions. Hence, emotion recognition is affected by inversion--an indicator for configural processing, and presentation time--an indicator for cognitive effort of processing. |
20192134 | Look before you leap: jumping ability affects distance perception. | Previous research has demonstrated that changing perceivers' action capabilities can affect their perception of the extent over which an action is performed. In the current study, we manipulated jumping ability by having participants wear ankle weights and examined the influence of this manipulation on the perception of jumpable and un-jumpable extents. When wearing ankle weights, jumpable gaps appeared longer than when not wearing ankle weights; however, for un-jumpable gaps, there was no difference in the apparent gap extent, regardless of whether the participant was wearing ankle weights. This suggests that the perception of a jumpable extent is affected by one's action boundary for jumping, but only if jumping is an action that can be performed over the extent. |
20192135 | Tolerance of stereopsis to conjunctive cyclorotation. | Stereopsis is largely unperturbed by various types of eye, head, and target movements. Here, we used a simple setup to investigate the limits of a previously untested type of stimulus motion on stereoscopic depth perception. Clockwise and counterclockwise rotations of an autostereogram were used to describe the limits of stereopsis to roll-tilt. The result showed intact depth perception with stimulus rotation up to approximately 12 degrees, regardless of rotation direction and viewing distance, indicating a tolerant mechanism for stereoscopic processing by the human neural system. |
20192136 | Pain control after total knee arthroplasty: a prospective study comparing local infiltration anesthesia and epidural anesthesia. | Postoperative pain control after total knee arthroplasty (TKA) is a well-known clinical problem. Efforts to treat it with the use of local anesthesia have been made, but the results have been contradictive. In the late 1990s, an infiltrated solution of ropivacaine/ketorolac/adrenaline was shown to be effective for this purpose, and this technique has since spread over the world. The purpose of this study was pare the local infiltration anesthesia technique with epidural anesthesia, which has been the most widely used technique in Sweden.Eighty-five patients received either local infiltration anesthesia or epidural anesthesia for postoperative pain relief. Postoperative morphine consumption, range of motion, walking ability, patient satisfaction, hospital stay, and time in the recovery room were measured. The groups were followed equally. The patients in the local infiltration anesthesia group were mobilized 24 hours earlier. On postoperative day one, 22 of 33 patients in the local infiltration anesthesia group could get in and out of bed without assistance. Only 1 of 31 patients in the epidural anesthesia group could manage this. On postoperative day two, 28 of 33 patients in the local infiltration anesthesia group could walk without pared to 5 of 31 in the epidural anesthesia group. Seventy-six percent of the local infiltration anesthesia patients were "very satisfied" with their postoperative pain control pared to 40% of the epidural anesthesia patients.The local infiltration anesthesia technique is better for postoperative pain relief in TKA than epidural anesthesia. It offers equal pain relief, faster mobilization, and more satisfied patients. No negative side effects were seen during the study. |
20192137 | Are patients' expectations of hip and knee arthroplasty fulfilled? A prospective study of 130 patients. | Total hip arthroplasty (THA) is the most successful procedure in orthopedic and trauma surgery. Patients' expectations of joint replacement surgery prior to and after the procedure are often discounted. This study investigated the expectations of patients before and 3 years after THA or total knee arthroplasty (TKA). A total of 130 patients (70 hips, 60 knees) received a modified FFbH-OA survey with 6 additional questions concerning patients' expectations before and 3 years after joint replacement surgery. The overall response rate was 78.8% (101 patients). Patients who underwent THA had a mean age of 63.7 years, and those who underwent TKA had a mean age of 67.4 years.Sixty-three percent of all respondents reported that their expectations had been fulfilled or exceeded 3 years postoperatively (THA, 65%; TKA, 61%). A high negative correlation in the THA group could be seen between patients' expectations and clinical scores: the lower the clinical score, the less the patient's expectations had been fulfilled. A statistically significant increase of change in personal relationships was found, as well as a statistically significant decrease in worries and plications than had been expected before joint replacement.Thirty-seven percent of all respondents felt that their expectations regarding joint replacement had not been fulfilled. Looking at the results of this study, the 37% of patients whose expectations had not been fulfilled did not exhibit a lower postoperative functioning than those who were satisfied. |
20192138 | Comparison of vacuum-assisted closure to the antibiotic bead pouch for the treatment of blast injury of the extremity. | The surgical care of batants involves treatment of massive extremity wounds from blast mechanism. Currently up to 70% bat wounds are extremity related. Clinical es for these patients are dependent on the care of these wounds. The Vacuum-Assisted Closure (VAC) Therapy system (KCI Inc, San Antonio, Texas) is ubiquitous in theater and is often considered the only way to treat these wounds. However, the VAC Therapy system is not without problems. It is expensive and requires extensive amounts of product and machinery, as well as functioning suction, and therefore a power source at all times. In addition, the VAC Therapy system requires a trained and vigilant nursing staff. We hypothesized that the antibiotic bead pouch would be a viable alternative to the VAC Therapy system for such blast injuries. We retrospectively analyzed 2 matched groups of 12 patients in terms of e and cost. We found that the VAC Therapy system produced more late methicillin-resistant Staphylococcus aureus infections (30%), more unanticipated returns to the operating room for wound problems (4:12 vs 0:12), and required more surgeries overall until closure of the wounds. In addition, the VAC Therapy system cost $12,000 more for 12 patients than the antibiotic bead pouch. We mend the bead pouch be considered as an equivalent option to the VAC Therapy system in the treatment of blast injury. |
20192140 | A comparative study of screw and helical proximal femoral nails for the treatment of intertrochanteric fractures. | The goal of this study was pare treatment es of screw proximal femoral nails and helical proximal femoral nails and to investigate the effectiveness of helical proximal femoral nails for the treatment of intertrochanteric fractures. Forty patients with intertrochanteric fractures were treated at our institution between January 2005 and January 2007, with a minimum follow-up of 1.5 years. Seventeen patients were treated with screw proximal femoral nails (mean patient age, 67 years; age range, 45-89 years; men:women ratio, 3:14), and 23 were treated with helical proximal femoral nails (mean patient age, 74 years; age range, 64-91 years; men:women ratio, 6:17). We evaluated mean operation time, amount of bleeding, time to ambulation, average union period, changes in neck shaft angle, plications, and performed radiographic reviews, telephone interviews, and direct contact interviews at an outpatient clinic. We evaluated postoperative function and mobility using social function scores and mobility scores.Helical proximal femoral nails produced better results in terms of social function scores, mobility scores, plication rates with statistical significance. No significant differences were found between the 2 nails in terms of mean operation time, amount of bleeding, average union period, time to ambulation, or neck shaft angle changes. Screw proximal femoral nails and helical proximal femoral nails are suitable implants for intertrochanteric fractures, but helical proximal femoral nails are better in terms of functional aspects plication rates. |
20192139 | Lateral tibial plateau fracture depression as a predictor of lateral meniscus pathology. | The goal of this study was to determine if the degree of lateral tibial plateau fracture depression puted tomography (CT) images predicted the presence of lateral meniscus tears. The study prised 85 patients who sustained a lateral tibial plateau fracture and underwent open reduction and internal fixation by the same surgeon. Degree of plateau depression was measured in millimeters by CT. Operative reports were retrospectively reviewed to determine if the lateral meniscus tear was intact or torn at the time of surgery. Twenty-eight patients had a lateral meniscus tear noted at the time of surgery. No significant differences existed in gender, mechanism or energy level of injury, Schatzker classification, or type of fracture among patients with a lateral meniscal tear pared to those without a tear. Patients with > or =10 mm of plateau depression had an eight-fold increase in risk of having a lateral meniscus pared to those with <10 mm of depression. Patients younger than 48 years had a four-fold increase in risk of having a lateral meniscus tear than older patients.This study demonstrated an association between the amount of tibial plateau depression and the likelihood of a lateral meniscus tear. These findings may be used to predict those who have sustained a tear of the lateral meniscus and to advise the surgeon to prepare for a repair. Further prospective studies using magnetic resonance imaging as a tool to evaluate the extent of soft tissue injuries in plateau fractures is needed. |
20192141 | Arthroscopy on anticoagulated patients: a retrospective evaluation of postoperative complications. | Anticoagulation monly needed for multiple medical conditions. The indications to discontinue anticoagulation for a simple procedure are controversial. Other surgical subspecialties have shown that keeping patients on warfarin during a simple procedure is safe. The purpose of this retrospective study was to evaluate the plications encountered for patients undergoing simple arthroscopic procedures while on warfarin. We hypothesized that anticoagulated patients undergoing simple arthroscopic procedures would have few surgical plications.Arthroscopic procedures performed over a 10-year period on warfarin-anticoagulated patients were retrospectively evaluated. Data collected included the procedure and orthopedic problem, the type of anesthesia, the medical condition requiring anticoagulation, the international normalized ratio (INR) at surgery, and all plications (bleeding, hematoma, delayed healing, prolonged postoperative course, infection, and plication). Twenty-four patients met the inclusion criteria. All had abnormal INR levels at time of surgery. Four patients were operated on emergently for septic joints, and 20 patients had elective arthroscopic procedures (10 knees, 10 shoulders). There were no major intraoperative bleeding problems. Seven patients had minor postoperative plications: 2 prolonged effusions and 5 prolonged ecchymosis. No plications were seen. Oral warfarin appeared to be a safe alternative to manipulating anticoagulation during the preoperative period for simple arthroscopic procedures. Minor plications consisting of ecchymosis were seen, but no plications were identified. |
20192142 | Autologous blood and corticosteroid injection and extracoporeal shock wave therapy in the treatment of lateral epicondylitis. | Lateral epicondylitis is mon disorder characterized by pain and tenderness over the lateral epicondyle. It occurs most frequently as a result of minor, unrecognized trauma during sports activities and occupation-related physical activities. The goal of this study was to evaluate the short-, medium-, and long-term effects of corticosteroid injection, autologous blood injection, and extracorporeal shock wave therapy in the treatment of lateral epicondylitis.Sixty patients (32 women, 28 men) with lateral epicondylitis were randomly divided into 3 groups: group 1 received a corticosteroid injection; group 2, an autologous blood injection, and group 3, extracorporeal shock wave therapy. Thomsen provocative testing, upper extremity functional scores, and maximal grip strength were used for evaluation. es were assessed at 4, 12, 26, and 52 weeks. Corticosteroid injection gave significantly better results for all e measures at 4 weeks; success rates in the 3 groups were 90%, 16.6%, and 42.1%, respectively. Autologous blood injection and extracorporeal shock wave therapy gave significantly better Thomsen provocative test results and upper extremity functional scores at 52 weeks; the success rate of corticosteroid injection was 50%, which was significantly lower than the success rates for autologous blood injection (83.3%) and extracorporeal shock wave therapy (89.9%). Corticosteroid injection provided a high success rate in the short term. However, autologous blood injection and extracorporeal shock wave therapy gave better long-term results, especially considering the high recurrence rate with corticosteroid injection. We suggest that the treatment of choice for lateral epicondylitis be autologous blood injection. |
20192143 | Computer-assisted 3-dimensional anthropometry of the scaphoid. | Scaphoid fracture fixation using a cannulated pression screw and the Matti-Russe procedure for the treatment of scaphoid nonunions are performed routinely. Surgeons performing these procedures need to be familiar with the anatomy of the scaphoid. A literature review reveals relatively few articles on this subject. The goal of this anatomical study was to measure the scaphoid using current technology and to discuss the findings with respect to the current, relevant literature.Computed tomography scans of 30 wrists were performed using a 64-slice SOMATOM Sensation CT system (resolution 0.6 mm) (Siemens Medical Solutions Inc, Malvern, Pennsylvania). Three-dimensional reconstructions from the raw data were generated by MIMICS software (Materialise, Leuven, Belgium). The scaphoid had a mean length of 26.0 mm (range, 22.3-30.7 mm), and men had a significantly longer (P<.001) scaphoid than women (27.861.6 mm vs 24.561.6 mm, respectively). The width and height were measured at 3 different levels for volume calculations, resulting in a mean volume of 3389.5 mm(3). Men had a significantly larger (P<.001) scaphoid volume than women (4057.86740.7 mm(3) vs 2846.56617.5 mm(3), respectively).We found considerable variation in the length and volume of the scaphoid in our cohort. We also demonstrated a clear correlation between scaphoid size and sex. Surgeons performing operative fixation of scaphoid fractures and corticocancellous bone grafting for nonunions need to be familiar with these anatomical variations. |
20192144 | Stringent patient selection in bulk allograft reconstructions. | We hypothesized that stringent patient selection in the use of large bulk structural allografts for limb preservation would positively affect es and plication rates by eliminating orbid or social factors known to contribute to the most detrimental sources of allograft failure: infection, fracture, and nonunion.Our selection criteria included patients who were younger than 50 years, nonsmokers, non-obese (body mass index <40), who did not receive radiation therapy to the recipient site perioperatively, and who underwent intercalary allograft reconstruction except in the upper extremity where osteoarticular allografts were permitted. es were assessed using the Musculoskeletal Tumor Society (MSTS) and Toronto Extremity Salvage Score (TESS) scoring systems. Twenty-three patients fulfilled our cohort inclusion criteria. The overall survival rate for the 23 allografts was 91% (21/23). Average MSTS and TESS scores were 76% and 87%, respectively. Eleven of 23 patients experienced at least plication requiring a second procedure. Musculoskeletal Tumor Society scores among patients experiencing plications averaged 83% vs 71% for patients experiencing at least plication. Average TESS scores were 89% and 86%, respectively.The results of our early experience indicate there is no appreciable difference plication rates among our series of patients stringently selected for bulk allograft pared to other previously reported studies. |
20192146 | Kyphoplasty for the treatment of painful osteoporotic thoracolumbar burst fractures. | This study explored the feasibility and clinical e of kyphoplasty for the treatment of painful osteoporotic thoracolumbar burst fractures without neurological deficit. A total of 25 consecutive patients with painful type-A3 amyelic thoracolumbar fractures without neurological deficit were treated by kyphoplasty. Pain was measured using the self-reporting visual analog pain scale (VAS) preoperatively, postoperatively, and at 6-month follow-up. Disability was measured using the Oswestry Disability Index (ODI) preoperatively, postoperatively, and at 6-month follow-up. The height of the fractured vertebral body, kyphotic angle, and spinal promise were measured preoperatively, postoperatively, and at 6-month follow-up. Relief of pain was achieved 24 hours postoperatively. Mean VAS score decreased from 8.2+/-1.3 preoperatively to 2.8+/-0.8 postoperatively (P<.05), and was maintained at 2.9+/-1.1 at 6-month follow-up. The ODI score varied from 68.2%+/-6.6% preoperatively to 35.3%+/-2.8% postoperatively (P<.05). Improvement was maintained at 6-month follow-up. Postoperatively, the height of anterior vertebrae (Ha) was restored from 61.5%+/-13.9% to 85.3%+/-10.6%, the height of midline vertebrae (Hm) restored from 73.0%+/-19.3% to 83.3%+/-7.4%, the kyphotic angle from 21.7 degrees +/-7.8 degrees to 8.6 degrees +/-6.6 degrees, and the spinal promise from 20.1%+/-4.1% to 17.8%+/-1.3%. At 6-month follow-up, maintenance of the height restoration and kyphotic deformity correction was found. No significant difference was noted in pre- and postoperative spinal promise. Kyphoplasty is a relatively safe and effective method for the treatment of painful osteoporotic thoracolumbar burst fractures. |
20192145 | The use of expandable cages in patients undergoing multilevel corpectomies for metastatic tumors in the cervical spine. | Expandable cages have been used successfully to reconstruct the anterior spinal column in the treatment of traumatic, neoplastic, infectious, and degenerative spine disease. To the best of our knowledge, no studies report the results of the use of expandable cages in patients undergoing multilevel corpectomies for cervical spine metastatic disease. We report our experience with the use of expandable cages in this subgroup of patients.From August 2006 to May 2008, 5 patients presenting with myelopathy, pain, and/or radiculopathy secondary to metastatic disease of the cervical spine underwent multilevel cervical corpectomies and placement of expandable cages in our institution. All procedures were supplemented with an anterior cervical plate and with posterior instrumentation to achieve a 360 degrees fusion. A visual analog scale (VAS), Nurick grade, Frankel grade, American Spinal Injuries Association (ASIA) grade, and Ranawat grade were used to evaluate patients pre- and postoperatively. The mean follow-up period was 13.2 months. Three patients underwent a 2-level corpectomy, 1 a 3-level corpectomy, and 1 a 4-level corpectomy. Postoperative imaging studies showed that all patients had correction of preoperative kyphosis. The mean VAS score was reduced from 6.4 to 1. All other indices of spinal cord injury measured improved postoperatively or were stabilized. Postoperative imaging studies showed stable constructs in 4 patients.The use of expandable cages in multilevel corpectomies for the treatment of metastatic cervical spine disease appears to be a safe and effective way to reconstruct the anterior column of the cervical spine, preventing further neurologic deterioration. |
20192147 | Evaluation of biomechanical and histological features of vertebrae following vertebroplasty using hydroxyapatite blocks. | Vertebroplasty was performed using hydroxyapatite blocks to examine the course pressive strength and histological features in a dog model. The vertebral fracture model was prepared by punching a hole in the center of the vertebra and at 4 sites around the vertebra (5 holes in total) from the front side of the vertebra using an air drill and hollowing the holes. Measurements were made on healthy vertebrae, vertebrae from the vertebral fracture model, vertebrae removed from animals immediately after vertebroplasty, vertebrae collected 1 and 2 months after vertebroplasty, and vertebrae untreated for 1 month after vertebral fracture. Histological examinations were also performed 1 and 2 weeks and 1 and 2 months after vertebroplasty with hydroxyapatite blocks. The strength of vertebrae in the fracture model immediately after vertebroplasty was significantly higher than that in the untreated fracture, and the strength of vertebrae 1 month after the procedure was equivalent to that of healthy vertebrae. Histologically, new bone formation was found around hydroxyapatite blocks 2 weeks after the procedure, and strong crosslinking between neighboring hydroxyapatite blocks was found after 1 month.These results suggest that hydroxyapatite blocks may be effective as filling material for vertebral fracture from both biomechanical and histological perspectives. |
20192148 | Impact of passive smoking on the bones of rats. | Many epidemiological surveys have identified smoking as a risk factor for osteoporosis, but it is unclear whether smoking has a direct effect on bone metabolism and if such an effect could cause osteoporosis. Therefore, we examined whether smoking causes osteoporosis based on the impact of smoke exposure on the bones of rats. A rat model of passive cigarette smoking was prepared by breeding rats in a cigarette-smoking box for 4 or 8 weeks. Histological changes, puted tomographic (CT) analysis, mechanical bone strength, and bone mineral density of the femur and lumbar vertebrae were examined in these rats and in control rats that were not exposed to smoke. Lower mechanical bone strength was observed in smoke-exposed rats, but these differences were not significant. Significantly lower bone mineral density was found in the femur (P<.01) and lumbar bones (P<.001) of 8-week smoke-exposed pared to controls. In a micro-CT scan of lumbar vertebrae, the bone volume, trabecular thickness, trabecular number, and trabecular separation differed significantly between smoke-exposed rats and controls. Histologically, the osteocytes in the smoke-exposed rats were small (approximately 25% of the size in controls), and decreased numbers of marrow cells and osteoblasts (P<.01), as well as a black carbon dust-like substance, were found in the bone of smoke-exposed rats. These results indicate that smoking significantly decreases bone mineral density, which causes osteoporosis, and the organizational changes in the bone suggest a direct effect of smoking on bone structure. Fewer marrow cells were present in the smoke-exposed rats, and a black carbon dust-like substance was observed. |
20192150 | Femoral stem displacement during closed reduction of a dislocated bipolar hemiarthroplasty of the hip. | This article describes a case of femoral stem displacement during closed reduction of a redislocated bipolar hemiarthroplasty of the hip in a 72-year-old woman who had undergone bipolar hemiarthroplasty using a polished, tapered cemented femoral stem. The polished, tapered cemented femoral stem is vulnerable to displacement when exposed to traction forces. Six days after bipolar hemiarthroplasty, the patient experienced her first dislocation, and immediate reduction of the dislocated hip was easily achieved. However, on the ninth postoperative day, redislocation occurred, and this time, reduction was not achieved. Subsequent radiographs revealed an unreduced state with posterosuperior dislocation of the hip and dissociation of the femoral stem at the cement-stem interface with proximal migration. Open reduction was then performed, and it was noted that the bipolar prosthesis had dislocated posterosuperiorly, the neck of the femoral stem was incarcerated between the short external rotators, and the femoral stem had migrated proximally by approximately 8 cm. The femoral stem was repositioned by freeing it from the short external rotators and gently tapping it into the cement mantle. Our surgical solution is questionable, because the stability of the stem is likely to be inadequate. According to the established study, no difference in stuffiness was observed before extraction and after reinsertion, which supports the surgical solution we chose. Pre-reduction analysis should be conducted to determine the cause and status of a dislocation, and open reduction should be performed if closed reduction fails when treating dislocated bipolar hemiarthroplasty patients. |
20192149 | Superior gluteal artery injury during iliosacral screw placement due to aberrant anatomy. | Percutaneous iliosacral screws are considered the standard of care for disruptions of the sacroiliac joint. This article describes a case of iatrogenic injury to the superior gluteal artery during iliosacral screw insertion and analyzes the possible reasons for plication.A 32-year-old man diagnosed with an unstable pelvic ring injury underwent percutaneous fixation of the right sacroiliac joint. A 2-cm skin incision was made, and a straight cannulated awl was placed with the tip directly lateral to the S1 body. A guide wire was inserted and a partially threaded 6.5-mm cannulated screw with a washer was then placed over the guide wire and was found to be in excellent position. At this time, increased bleeding from the incision was observed. The incision was enlarged and dissection was carried down through the muscle. The bleeding vessel could not be visualized. Therefore, the wound was packed with sponges, and coil embolization of the right superficial gluteal artery was successfully performed.Analysis of the angiography reveled that our patient's superficial branch of the superior gluteal artery measured more than twice the average length reported in a previous anatomic study. We believe this is the first case of superior gluteal artery bleeding due to aberrant superior gluteal artery anatomy. When planning iliosacral screw insertion, the possibility of anatomical variance of the superior gluteal artery should be acknowledged and sought after in preoperative angiography, when available. |
20192151 | Intramedullary bone fragment obstructing passage of reaming guide wire with iatrogenic fractured tibia. | Reamed interlocking intramedullary fixation is the treatment of choice for displaced tibial shaft fractures in adults. In most cases it can be performed without difficulty; however, technical difficulties may be encountered during nailing in some cases. This article describes a case of closed nailing for a tibial shaft fracture in which intramedullary guide wire was obstructed by a small intramedullary bone fragment in the distal fracture segment. Forceful reaming and insertion of the nail led to a break in the cortex of the distal fragment and bending of guide wire. Finally, open reduction and intramedullary nailing was performed to retrieve the guide wire and intramedullary bone fragment and fix the minuted fracture with multiple close fragments in proximity to the fracture site should be preoperatively scrutinized to look for intramedullary bone fragment or a fragment that could be pushed in the intramedullary canal during the intramedullary nailing. The surgeon can then anticipate the potential operative difficulty that may be encountered during closed nailing of such a fracture; and the patient can be counseled, as open nailing is a safer and viable option. Finally it is pertinent that even if this fracture type is overlooked, catastrophe can be avoided by properly following all the steps of intramedullary nailing. |
20192153 | Simultaneous dorsal dislocations of the carpometacarpal joints of all four fingers. | A 57-year-old right-hand-dominant woman was involved in a motor vehicle collision. Upon examination, her right hand was markedly deformed and swollen, with limited range of movement. Plain radiographs revealed dorsal dislocations of the index, long, ring, and small finger carpometacarpal joints and an avulsion fracture of the dorsal aspect of the capitate. Closed reduction was unsuccessful. Closed reduction under general anesthesia was successful on the carpometacarpal joint of the ring and small fingers, however, the long and index fingers remained irreducible. An open approach revealed that a joint capsule was interposed in the carpometacarpal joints of the long and index fingers, preventing reduction. Kirschner wires were placed through the base of the small and ring finger metacarpals into the carpus. Additional K-wires were placed across the base of the index and long finger metacarpals into the carpus, and removed at 6 weeks. The avulsion fracture of the capitate was not addressed. Follow-up at 24 months demonstrated full range of motion in all fingers. Her DASH e Measure score was 1.7. She was pain free, had full grip strength, and returned to work full-time. Whether patients are treated closed or open, appropriate treatment of carpometacarpal dislocations usually leads to excellent es. If closed reduction is unsuccessful, open treatment is required to address any soft tissue that is preventing reduction. Although urgent treatment is preferred, delay in reduction of up to 4 weeks has been shown not promise results. |
20192152 | Nonoperative biological treatment approach for partial Achilles tendon lesion. | Tendon injuries, especially those of the Achilles tendon, are major concerns in sports medicine. The clinical presentation can be acute or chronic and the pathologic findings can range from peritendonitis to full-thickness tendon rupture. Nonsurgical treatment is not always successful; in particular, significant partial ruptures seem to respond poorly to conservative measures and do not improve with time. Surgery is most often considered the favored treatment option for this kind of lesion to obtain pain relief and full functionality with long-standing effects.This article describes a case of a partial tear of the Achilles tendon in a petitive athlete where surgical treatment was avoided in favor of a new biological approach. We applied autologous platelet growth factors through multiple platelet-rich plasma injections; approximately 6.5 billion platelets were injected into the lesion 3 times, 7 days apart. The treatment with platelet-rich plasma and a progressive rehabilitation program allowed the patient to play for 20 minutes in a basketball game 64 days after the trauma and in a full game 75 days after the trauma. To date, 18 months later, he has participated regularly in all the season's games and received no further treatment for his tendon.The fast tissue repair, confirmed by magnetic resonance and ultrasound imaging, allowed a swift return to full functionality petitive sports activity, suggesting a possible role of platelet growth factors in promoting rapid tendon healing with high-quality tissue. This biological approach may represent a less-invasive therapeutic option even in cases where severe tendon lesions are candidates for surgical treatment. |
20192154 | Pigmented villonodular synovitis of the elbow treated with the Tsuge wide joint exposure technique. | Pigmented villonodular synovitis (PVNS) is a benign, locally aggressive disease of the synovium; its cause remains unclear. The most frequently involved joint is the knee, followed by the hip, ankle, wrist, and shoulder. Pigmented villonodular synovitis of the elbow joint is rare. Synovectomy is currently believed to be the best treatment for PVNS. Open or arthroscopic synovectomy is usually selected. During synovectomy for PVNS, the possibility of local recurrence after surgery must be considered. The recurrence rate after synovectomy of any joint for PVNS is approximately 40%. Therefore, surgical treatment for PVNS of the elbow requires sufficient removal of the lesion. For good functional results, prevention of postoperative joint stiffness is also necessary. This article describes a case of a 29-year-old woman with PVNS of the right elbow who was treated by total synovectomy using the Tsuge technique. Tsuge reported a new surgical technique for debridement arthroplasty using a posterolateral approach to the elbow in 1987. He has also reported using this procedure during arthroplasty for posttraumatic stiff elbow and for synovectomy in rheumatoid arthritis. This approach permits easy dislocation of the elbow and provides a good view of the whole joint. Although the recurrence rate of PVNS of the elbow is high, our patient has retained good elbow function with no evidence of local recurrence at 30 months postoperatively. |
20192155 | Chronic closed talus dislocation: a rare presentation and treatment dilemma. | A chronic presentation of closed dorsolateral dislocation of the talus is a rare injury. A 35-year-old woman presented with pain and deformity of the right foot of 6 months' duration. Her medical history was significant for rheumatoid arthritis, for which she was being treated with steroids. Radiographs puted tomography of the right foot showed dorsolateral talar dislocation with fracture of the medial malleolus. Dislocation of the talus from the tibiotalar, talocalcaneal, and talonavicular joints was indicative of talus dislocation with a fracture of the medial malleolus rather than a fracture-dislocation of the ankle joint. Because of chronic presentation of the injury and an inability to reduce this talus dislocation by closed methods, open total talectomy was performed. At 2-year follow-up, the patient had an AOFAS score of 78. The patient had an obvious limp on the affected limb but managed her activities of daily living well without a shoe raise or brace. Because of the severe varus inversion deformity of the foot preoperatively, the patient was not able to walk. Postoperatively, the deformity was corrected and the patient was able to stand and walk; she was satisfied with the e of the surgery.To our knowledge, this is the first report of chronic closed dorsolateral talus dislocation. We mend that chronic closed isolated dorsolateral talus dislocation can be effectively managed by total talectomy. |
20192156 | Tibial hemimelia and femoral bifurcation. | Femoral bifurcation and tibial agenesis are rare anomalies and have been described in both the plex and tibial agenesis-ectrodactyly syndrome. This article presents a case of plex without hand ectrodactyly. Tibial agenesis-ectrodactyly syndrome and plex are variants of tibial field defect, which includes distal femoral duplication, tibial aplasia, oligo-ectrodactylous toe defects, and preaxial polydactyly, occasionally associated with hand ectrodactyly.This article describes the case of a patient with bilateral tibial hemimelia and left femoral bifurcation. The proximal tibial anlage had not been identified in the patient's left leg. After failed fibular transfer procedure, the knee was disarticulated. The other leg was treated with tibiofibular synostosis and centralization of fibula to os calcis. At 7-year follow-up, the patient ambulates with an above-knee prosthesis and uses an orthopedic boot for ankle stability.In patients with a congenital absence of the tibia, accurate diagnosis is of the utmost importance in planning future treatment. In the absence of proximal tibial anlage, especially in patients with femoral bifurcation, the knee should be disarticulated. Tibiofibular synostosis is a good choice in the presence of a proximal tibial anlage and good quadriceps function. |
20192157 | Continuous surface functionalization of flame-made TiO2 nanoparticles. | Hydrophilic TiO(2) particles made in a flame aerosol reactor were converted in situ to hydrophobic ones by silylation of their surface hydroxyl groups. So the freshly formed titania aerosol was mixed with a fine spray of octyltriethoxysilane (OTES) in water/ethanol solution and functionalized continuously at high temperature. The extent of functionalization and structure of that surface layer were assessed by thermogravimetric analysis (TGA) coupled to mass spectroscopy (MS), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and Raman spectroscopy. Product particles were characterized also by transmission electron microscopy (TEM), X-ray diffraction, and nitrogen adsorption. The influence of titania specific surface area (SSA) and OTES solution concentration on the functional group surface density was investigated. The titanium dioxide surface was covered with functional groups (up to 2.9 wt %) that were thermally stable up to 300 degrees C in air at an average density of 2 OTES/nm(2). Such surface-functionalized particle suspensions in 2-ethylhexanoic acid and xylene were stable over several weeks. In contrast, as-prepared hydrophilic TiO(2) precipitated within days in these solvents. |
20192158 | Highly ordered self-assemblies of submicrometer Cu2O spheres and their hollow chalcogenide derivatives. | Highly ordered superlattices assembled from transition metal oxide/sulfide submicrometer particles are difficult to prepare due to lack of monodisperse primary building blocks. In this work, we have successfully synthesized monodisperse Cu(2)O spheres with diameters in the submicrometer regime of 130-135 nm. Using the as-prepared Cu(2)O spheres as solid precursor, uniform hollow CuS and CuSe derivatives have also been synthesized in solution media. More importantly, a range of two-dimensional and three-dimensional superlattices of Cu(2)O, CuS, and CuSe solid/hollow spheres have been assembled for the first time. Without assistance of conventional sacrificing solid templates, the degree of ordering achieved in these superlattices parable to those reported for well-studied silica and polystyrene beads. The realization of these self-assembled superlattices may provide a new way of thin film design and fabrication for this class of photosensitive semiconducting materials using their prefabricated building blocks. |
20192159 | Electrofluidic gating of a chemically reactive surface. | We consider the influence of an electric field applied normal to the electric double layer at a chemically reactive surface. Our goal is to elucidate how surface chemistry affects the potential for field-effect control over micro- and nanofluidic systems, which we call electrofluidic gating. The charging of a metal-oxide-electrolyte (MOE) capacitor is first modeled analytically. We apply the Poisson-Boltzmann description of the double layer and impose chemical equilibrium between the ionizable surface groups and the solution at the solid-liquid interface. The chemically reactive surface is predicted to behave as a buffer, regulating the charge in the double layer by either protonating or deprotonating in response to the applied field. We present the dependence of the charge density and the electrochemical potential of the double layer on the applied field, the density, and the dissociation constants of ionizable surface groups and the ionic strength and the pH of the electrolyte. We simulate the responses of SiO(2) and Al(2)O(3), two widely used oxide insulators with different surface chemistries. We also consider the limits to electrofluidic gating imposed by the nonlinear behavior of the double layer and the dielectric strength of oxide materials, which were measured for SiO(2) and Al(2)O(3) films in MOE configurations. Our results clarify the response of chemically reactive surfaces to applied fields, which is crucial to understanding electrofluidic effects in real devices. |
20192160 | Hydrogen-bond-directed giant vesicles of guanosine derivatives in water: formation, structure, and stability. | Hydrogen-bond-directed giant supramolecular vesicles (diameter 1.20 +/- 0.30 microm (SD)) of an alkylsilylated deoxyguanosine derivative, 2a, were prepared faciley by mixing a small volume of a 2a/THF solution with water. The formation of 2-D inter-guanine hydrogen-bond networks of 2a within the vesicles was indicated by IR spectra. The vesicle solution was stable enough for more than 30 days, in a wide range of temperatures, and between pH 4 and 10 without showing lysis, fusion, precipitation, or leakage of the encapsulated fluorescent probe. In a typical micrometer-sized vesicle, a sufficiently large internal water phase for encapsulating water-soluble substances was surrounded by a multilamellar membrane 15-20 nm in thickness, which posed of 6-9 layers of 2-D hydrogen-bond-directed sheet assemblies. AC-mode AFM observation of the vesicle on a silicon substrate further demonstrated the high stability and deformable properties of the vesicle membrane under vacuum or mechanical stress. The formation and properties of the vesicle membrane in water were analyzed from the viewpoint of the 2-D hydrogen-bond-directed sheet assemblies, and the scope of the design principle to use nonpolar soft segments as the shielding units of the hydrogen-bond networks in water is discussed. |
20192161 | Supramolecular photochemistry in beta-cyclodextrin hosts: a TREPR, NMR, and CIDNP investigation. | A systematic investigation of the photochemistry and ensuing radical chemistry of three guest ketones encapsulated in randomly methylated beta-cyclodextrin (beta-CD) hosts is reported. Dibenzyl ketone (DBK), deoxybenzoin (DOB), and benzophenone (BP) triplet states are rapidly formed after photolysis at 308 nm. Time-resolved electron paramagnetic resonance (TREPR) spectroscopy, steady-state NMR spectroscopy, and time-resolved chemically induced nuclear polarization (TR-CIDNP) experiments were performed on the plexes and on the ketones in free solution parison. The major reactivity pathways available from these excited states are either Norrish I alpha-cleavage or H-atom abstraction from the interior of the CD capsule or the solvent. The DOB triplet state undergoes both reactions, whereas the DBK triplet shows exclusively alpha-cleavage and the BP triplet shows exclusively H-atom abstraction. Radical pairs are observed in beta-CDs by TREPR, consisting of either DOB or BP ketyl radicals with sugar radicals from the CD interior. The TREPR spectra acquired in CDs are substantially broadened due to strong spin exchange. The electron spin polarization mechanism is mostly due to S-T(0) radical pair mechanism (RPM) in solution but changes to S-T(-) RPM in the CDs due to the large exchange interaction. The TR-CIDNP results confirm the reactivity patterns of all three ketones, and DOB shows strong nuclear spin polarization from a novel rearrangement product resulting from the alpha-cleavage reaction. |
20192164 | Effect of organometallic fuel additives on nanoparticle emissions from a gasoline passenger car. | Particle size measurements were performed on the exhaust of a car operating on a chassis dynamometer fueled with standard gasoline and gasoline containing low levels of Pb, Fe, and Mn organometallic additives. When additives were present there was a distinct nucleation mode consisting primarily of sub-10 nm nanoparticles. At equal molar dosing Mn and Fe gave similar nanoparticle concentrations at the tailpipe, whereas Pb gave a considerably lower concentration. A catalytic stripper was used to remove the ponent of these particles and revealed that they were mainly solid and, because of their association with inorganic additives, presumably inorganic. Solid nucleation mode nanoparticles of similar size and concentration to those observed here from a gasoline engine with Mn and Fe additives have also been observed from modern heavy-duty diesel engines without aftertreatment at idle, but these solid particles are a small fraction of the primarily volatile nucleation mode particles emitted. The solid nucleation mode particles emitted by the diesel engines are likely derived from pounds in the lubrication oil, although carbonaceous particles cannot be ruled out. Significantly, most of these solid nanoparticles emitted by both engine types fall below the 23 nm cutoff of the PMP number regulation. |
20192165 | Versatile intramolecular aza-Prins and Prins cyclization of aryl epoxides: a facile synthesis of diaza-, oxa-aza-, and dioxa-bicycles. | Aryl epoxides undergo coupling smoothly with (E)-hex-3-ene-1,6-ditosylamide in the presence of 10 mol % p-TSA in 1,2-dichloroethane at 75 degrees C to produce the corresponding 1,5-ditosyl-octahydro-1H-pyrrolidino[3,2-c]pyridines in good yields with high trans-selectivity, whereas the coupling of (Z)-hex-3-ene-1,6-ditosylamide gave cis-fused octahydro-1H-pyrrolidino[3,2-c]pyridines predominantly. The use of readily available p-TSA makes this method simple, convenient, and practical. |
20192166 | Hosted and free-floating metal-bearing atmospheric nanoparticles in Mexico City. | Nanoparticles (NPs) are ubiquitous in the atmosphere. Because of their small sizes, they can travel deeply into the lungs and other parts of the body. Many are highly reactive bined with their large surface areas, means they can seriously affect human health. Their occurrences in the atmosphere and their biological effects are not well-understood. We focus on NPs that were either free-floating or hosted within large aerosol particles (aerodynamic diameter 50-300 nm) and consist of or contain transition or post-transition metals (m-NPs). The samples were collected from ambient air above Mexico City (MC). We used transmission electron microscopy to measure their sizes positions. More than half of the 572 m-NPs that we analyzed contain two or more metals, and Fe, Pb, or Zn occurs in more than 60%. Hg occurs in 21% and is especially abundant in free-floating m-NPs. We find that m-NPs mon in polluted air such as in the MC area and, by inference, presumably other megacities. The range and variety positions of m-NPs that we encountered, whether free-floating or hosted within larger aerosol particles, indicate plicated occurrences that should be considered when evaluating the health effects of m-NPs plex urban areas. |
20192167 | VOC removal and deodorization of effluent gases from an industrial plant by photo-oxidation, chemical oxidation, and ozonization. | The efficiency of photo-oxidation, chemical oxidation by sodium hypochlorite, and ozonization for the industrial-scale removal of volatile pounds (VOCs) and odors from gaseous emissions was studied by applying these treatments (in an experimental system) to substances passing through an emission stack of a factory producing maize derivatives. Absorption and ozonization were the most efficient treatment, removing 75% and 98% of VOCs, respectively, while photo-oxidation only removed about 59%. The emitted pounds and odors were identified and quantified by gas chromatography-mass spectrometry (in full-scan mode). In addition to presenting the results, their implications for selecting optimal processes for treating volatile emissions are discussed. |
20192168 | Biodegradation in a partially saturated sand matrix: compounding effects of water content, bacterial spatial distribution, and motility. | Bacterial pesticide degraders are generally heterogeneously distributed in soils, leaving soil volumes devoid of degradation potential. This is expected to have an impact on degradation rates because the degradation of pollutant molecules in such zones will be contingent either on degraders colonizing these zones or on pollutant mass transfer to neighboring zones containing degraders. In a model system, we quantified the role exerted by water on mineralization rate in the context of a heterogeneously distributed degradation potential. Alginate beads colonized by Pseudomonas putida KT2440 were inserted at prescribed locations in sand microcosms so that the initial spatial distribution of the mineralization potential was controlled. The mineralization rate was strongly affected by the matric potential (decreasing rate with decreasing matric potential) and by the initial distribution of the degraders (more aggregated distributions being associated with lower rates). The mineralization was diffusion-limited, as confirmed with a mathematical model. In wet conditions, extensive cell dispersal was observed for the flagellated wild type and, albeit to a lesser extent, for a nonflagellated mutant, partially relieving the diffusion limitation. Dry conditions, however, sustained low mineralization rates through bined effects of low pollutant diffusivity and limited degrader dispersal. |
20192169 | Reactive organic gas emissions from livestock feed contribute significantly to ozone production in central California. | The San Joaquin Valley (SJV) in California currently experiences some of the highest surface ozone (O(3)) concentrations in the United States even though it has a population density that is an order of magnitude lower than many urban areas with similar ozone problems. Previously unrecognized agricultural emissions may explain why O(3) concentrations in the SJV have not responded to traditional emissions control programs. In the present study, the ozone formation potentials (OFP) of livestock feed emissions were measured on representative field samples using a transportable smog chamber. Seven feeds were considered: cereal silage (wheat grain and oat grain), alfalfa silage, corn silage, high moisture ground corn (HMGC), almond shells, almond hulls, and total mixed ration (TMR = 55% corn silage, 16% corn grain, 8% almond hulls, 7% hay, 7% bran + seeds, and 5% protein + vitamins + minerals). The measured short-term OFP for each gram of reactive organic gas (ROG) emissions from all livestock feed was 0.17-0.41 g-O(3) per g-ROG. For reference, OFP of exhaust from light duty gasoline powered cars under the same conditions is 0.69 +/- 0.15 g-O(3) per g-ROG. Model calculations were able to reproduce the ozone formation from animal feeds indicating that the measured pounds account for the observed ozone formation (i.e., ozone closure was achieved). Ethanol and other alcohol species accounted for more than 50% of the ozone formation for most types of feed. Aldehydes were also significant contributors for cereal silage, high moisture ground corn, and total mixed ration. Ozone production calculations based on feed consumption rates, ROG emissions rates, and OFP predict that animal feed emissions dominate the ROG contributions to ozone formation in the SJV with total production of 25 +/- 10 t O(3) day(-1). The next most significant ROG source of ozone production in the SJV is estimated to be light duty vehicles with total production of 14.3 +/- 1.4 t O(3) day(-1). The majority of the animal feed ozone formation is attributed to corn silage. Future work should be conducted to reduce the uncertainty of ROG emissions from animal feeds in the SJV and to include this significant source of ozone formation in regional airshed models. |
20192170 | Structural and dynamic aspects of hydration of HAsO4(-2): an ab initio QMCF MD simulation. | An ab initio quantum mechanical charge field simulation has been carried out in order to obtain molecular level insight into the hydration behavior of HAsO4(-2), one of the major biologically ponents of As(V) oxoanion in neutral to slightly alkaline aqueous medium. Moreover, a geometrical definition of hydrogen bonding has been used to probe and characterize both solute-solvent and solvent-solvent hydrogen bonding present in the system. The asymmetry of the anion induced by the protonation of one of the oxygens of the arsenate anion causes rather irregular hydration structure. The nonprotonated oxygen atoms preferably form relatively stable hydrogen bonds with two to three water molecules in their vicinity, while the protonated oxygen forms one or two hydrogen bonds, weaker than water-water hydrogen bonds. The two types of As-O distances obtained from the simulation (1.68 and 1.78 A for the protonated and nonprotonated oxygens, respectively) are in good agreement with the experimental data. The two types of As-O stretching frequencies obtained from the simulation (855 and 660 cm(-1) reproduce well the experimental ATR-FTIR results (859 and 680-700 cm(-1)). |
20192172 | Thermodynamic properties of aqueous polyatomic ions at extreme temperatures and pressures. | Recently a theoretical treatment (J. Phys. Chem. B 2009, 113, 2398-2404) was developed for predicting the standard state thermodynamic properties of electrolytes up to and beyond the critical temperature of water (1273 K and at pressures up to 1000 MPa). In general, the model requires sufficient data at 298.15 K including the Gibbs free energy of hydration and at two higher temperatures to fix two constants for each electrolyte. munication describes an extension of this "two constant" theory to thermodynamic properties of polyatomic ions for which no accurate data for the Gibbs free energy of hydration exits at 298.15 K. |
20192171 | Effects of pore-scale heterogeneity and transverse mixing on bacterial growth in porous media. | Microbial degradation of contaminants in the subsurface requires the availability of nutrients; this is impacted by porous media heterogeneity and the degree of transverse mixing. Two types of microfluidic pore structures etched into silicon wafers (i.e., micromodels), (i) a homogeneous distribution of cylindrical posts and (ii) aggregates of large and small cylindrical posts, were used to evaluate the impact of heterogeneity on growth of a pure culture (Delftia acidovorans) that degrades (R)-2-(2,4-dichlorophenoxy)propionate (R-2,4-DP). Following inoculation, dissolved O2 and R-2,4-DP were introduced as two parallel streams that mixed transverse to the direction of flow. In the homogeneous micromodel, biomass growth was uniform in pore bodies along the center mixing line, while in the aggregate micromodel, preferential growth occurred between aggregates and slower less dense growth occurred throughout aggregates along the center mixing line. The homogeneous micromodel had more rapid growth overall (2 times) and more R-2,4-DP degradation (9.5%) than the aggregate pore structure (5.7%). Simulation results from a pore-scale reactive transport model indicate mass transfer limitations within aggregates along the center mixing line decreased overall reaction; hence, slower biomass growth rates relative to the homogeneous micromodel are expected. Results from this study contribute to a better understanding of the coupling between mass transfer, reaction rates, and biomass growth plex porous media and suggest successful implementation and analysis of bioremediation systems requires knowledge of subsurface heterogeneity. |