bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical Analysis of Conditional Heteroskedasticity in Time Series of Stock Returns and Asymmetric Effect on Volatility
Authors: Kumar Rakesh , Dhankar Raj S.
Published: February 2010

This article investigates the presence of conditional heteroskedasticity in time series of US stock market returns, and the asymmetric effect of good and bad news on volatility. Further, the study also analyzes the relationship between stock returns and conditional volatility, and standard residuals. The daily opening and closing prices of S&P 500 and NASDAQ 100 are used for the period January 1990 to December 2007. The study applies GARCH (1, 1) and T-GARCH (1, 1) to examine the heteroskedasticity and the asymmetric nature of stock returns respectively. The results of the study suggest the presence of the heteroskedasticity effect and the asymmetric nature of stock returns. Further, analyzing the relationship, the study reports a negative significant relationship between stock returns and conditional volatility. However, the relationship between stock returns and standardized residuals is found to be significant. This study provides a robustness test of the conditional volatility and asymmetric impact of good and bad news. These findings bring out that investors adjust their investment decisions with regard to expected volatility, however, they expect extra risk premium for unexpected volatility.
Reduction in surface contamination with antineoplastic drugs in 22 hospital pharmacies in the US following implementation of a closed-system drug transfer device
Authors: Sessink Paul JM , Connor Thomas H , Jorgenson James A , Tyler Timothy G
Published: February 2010

Purpose. Surface contamination with the antineoplastic drugs cyclophosphamide, ifosfamide, and 5-fluorouracil was compared in 22 US hospital pharmacies following preparation with standard drug preparation techniques or the PhaSeal® closed-system drug transfer device (CSTD).

Methods. Wipe samples were taken from biological safety cabinet (BSC) surfaces, BSC airfoils, floors in front of BSCs, and counters and analyzed for contamination with cyclophosphamide, ifosfamide, and 5-fluorouracil. Contamination was reassessed several months after the implementation of the CSTD. Surface contamination (ng/cm2) was compared between the two techniques and evaluated with the Signed Rank Test.

Results. Using the CSTD compared to the standard preparation techniques, a significant reduction in levels of contamination was observed for all drugs (cyclophosphamide: p < 0.0001; ifosfamide: p < 0.001; 5-fluorouracil: p < 0.01). Median values for surface contamination with cyclophosphamide, ifosfamide, and 5-fluorouracil were reduced by 95%, 90%, and 65%, respectively.

Conclusions. Use of the CSTD significantly reduces surface contamination when preparing cyclophosphamide, ifosfamide, and 5-fluorouracil as compared to standard drug preparation techniques.
Effects of a Mail and Telephone Intervention on Breast Health Behaviors
Authors: Bowen Deborah J. , Powers Diane
Published: February 2010

This study evaluated a mail and telephone intervention to improve breast health behaviors while maintaining quality of life. Women recruited from the general public were randomized to a stepped-intensity intervention consisting of mailings, telephone calls, and counseling (if requested or appropriate given a woman’s genetic risk for breast cancer) or to a delayed treatment control group. Outcomes (mammography screening and quality of life) were measured at baseline in a telephone survey and again at a 12-month follow-up period. Women in the intervention group significantly increased screening mammography uptake by 12% and quality of life by 5.3 scale points compared to control participants. Changes in knowledge of breast cancer, genetic testing, and cancer worry all significantly predicted intervention changes. This successful intervention can help women make better breast health choices without causing increased worry.
Grass burning under our feet: Indigenous enterprise development in a political economy of whiteness
Authors: Banerjee Subhabrata , Tedmanson Deirdre
Published: February 2010

In this article we discuss some of our findings from two research projects that explore opportunities for Indigenous enterprise development in remote locations in Northern and Central Australia. Based on a series of focus groups and in-depth interviews with Indigenous community leaders, Traditional Owners, government officials, Land Council officials and other stakeholders, we discuss barriers to economic development faced by Indigenous communities in remote regions. We argue that many of these barriers are the material effects of discursive practices of ‘whiteness’ in the political economy. We discuss the relationships between institutions and Indigenous communities that constitute the Indigenous political economy and argue that these relationships are informed by discursive practices of whiteness and colonial-capitalist relations of power. We conclude by discussing the implications of our findings for management learning and public policy.
Dialogical Relationship between Identity and Learning
Authors: Ligorio M. Beatrice
Published: February 2010

This paper highlights some connections between cultural psychology, educational psychology, and identity psychology. This aim is pursued through the constructivist view of conceptualized learning as building knowledge. It is contended that identities should explicitly be considered as part of this process. Useful approaches to explore the relationship between learning and identity are the Dialogical Self Theory (DST) and the Communities of Learning model (CoL), both of which demonstrate a shared interest in dialogue and constructivism. DST defines the self as being composed of a set of I-positions, which are constantly in dialogue and in movement. The CoL model conceptualizes the classroom as a set of cultural contexts where dialogues permit the analysis of context and also shape it. Empirical examples of how relevant concepts related to learning, such as motivation and sense-making, can be viewed as innovation of the self are discussed.
Structural Appraisal-based Different Approach to Estimate the Remaining Fatigue Life of Railway Bridges
Authors: Siriwardane S.A.S.C. , Ohga M. , Dissanayake P.B.R. , Kaita T.
Published: February 2010

The current fatigue life estimation methods of railway bridges are generally based on combinations of measured strain histories, Miner’s rule, and railway code provided fatigue curve. Even though the past measured strain histories are available for major bridges, most of the old bridges do not have past strain measurements. Furthermore, in case of existing railway bridges where the detailed loading history is known, Miner’s rule might provide incorrect results because of its omission of load sequence effect. These reasons hinder the usage of current methods to estimate the realistic remaining fatigue life of most of the existing railway bridges. Therefore, a new method is presented in this article to estimate remaining fatigue life of riveted railway bridges. The method mainly consists of predicted stress histories, recently developed sequential law and fully known Wöhler curve. Here, it is essential to use the fully known Wöhler curve as the related fatigue curve. Hence, the technique, which utilizes transfer of the partially known Wöhler curve to fully known curve, is also discussed in this article. Further, this method describes a reasonably accurate procedure to obtain the past stress histories from present day measured strains. Initially, the article describes the proposed method for remaining fatigue life estimation. Then the sequential law and associated fully known S-N curve determination procedure are verified by comparing theoretical fatigue life, damage behavior with real fatigue life and damage behavior of few materials. Finally, the remaining fatigue life of an existing railway bridge is estimated. Hence, validity and merits of the proposed method is confirmed by comparing the results with previous method-based fatigue lives.
Locating Nonlinear Components in Periodic Structures using Nonlinear Effects
Authors: Peng Z.K. , Lang Z.Q. , Chu F.L. , Meng G.
Published: February 2010

In this study, an effective method is developed to detect the position of nonlinear components in periodic structures. The detection procedure requires exciting the nonlinear systems only once by using a sinusoidal-like input which has two frequency components. The effectiveness of this method is demonstrated by numerical studies. As the position of a nonlinear component often corresponds to the location of defect in periodic structures, this new method is of great practical significance in fault diagnosis for mechanical and structural systems.
Vibration-based Damage Detection to the Composite Tank Filled with Fluid
Authors: Wensong Zhou  , Zhanjun Wu  , Mevel Laurent
Published: February 2010

Demand of composite fuel tank for space vehicles keeps increasing globally in the aerospace industry, and requires of a mean to detect the structural damage or predict its service life. As important and valid tools, in the past years, lots of nondestructive evaluation techniques have been developed, and they are carried out according to a regular time schedule. The structure has to be taken out of service during each inspection, causing serious financial implications for the user. That is why much research effort is now focused on real-time monitoring techniques. Optical grating fiber attracts more and more attention due to its excellent sensing and mechanical performances and ability of monitoring online. But it still can only measure the local deformation, but not the damage that is far away from the location of optical fiber sensors. Statistical model-based vibration-based monitoring methods have proved to be useful for the detection and localization of structural damages which might occur far from the location of the sensors. An experimental investigation on the modal properties and dynamic response of composite fuel tank filled with fluid under external excitation in the transverse direction are reported, and a vibration signal, which was obtained when the composite fuel tank filled with water was under impulsion until it failed. Proposed in this study is a method to detect the damage of the composite fuel tank with the scarce gradual damaged vibration signal. The experiment setup is also described in detail with inclusion of modeling a damaged situation of a structure. The damage detection algorithm is developed by applying a residually generated form of a subspace-based covariance-driven identification method and the vibration signal analysis. Results of the modal identification and the damage detection are reported in this article.
Social paediatrics: creating organisational processes and practices to foster health care access for children ‘at risk’
Authors: Lynam M. Judith , Loock Christine , Scott Lorine , Wong Sabrina M. , Munroe Valerie , Palmer Becky
Published: February 2010

In recent years understanding and addressing child health inequities has become a priority for research and practice. In this paper we share research insights on an approach that shows promise for engaging across the spectrum of health services to foster access to services and supports for child development to reduce child health inequities. As pathways of influence on children’s health and development extend beyond the biomedical domain new approaches to practice are needed to foster health care access and to mobilise needed supports. The Social Paediatrics Initiative has been introduced in one of Canada’s poorest inner city neighbourhoods where a disproportionate number of children experience adverse childhood events and enter school developmentally delayed. The research was undertaken in partnership with practitioners, community based organisations and the formal health services sector. The study gathered data from parents, community members and clinicians to understand the range of conditions that interfere with access to health care and to illustrate the ways the Social Paediatrics Initiative sought to foster access and provide care that was responsive to the health and developmental needs of children at risk because of their social and material circumstances. In particular we illustrate ways in which intersectoral and interdisciplinary partnerships enabled clinicians to provide needed supports to address the social determinants of health.
Penile prostheses
Authors: Bettocchi Carlo , Palumbo Fabrizio , Spilotros Marco , Palazzo Silvano , Saracino Gabriele A. , Martino Pasquale , Battaglia Michele , Selvaggi Francesco P. , Ditonno Pasquale
Published: February 2010

Penile prosthesis implantation is recognized as a valid option to obtain an artificial erection satisfactory for sexual intercourse in those patients in which a pharmacological approach is contraindicated or ineffective. Penile prostheses are subbject to continuous development and they are achieving ever better mechanical reliability and safety. The devices are divided into two general types: semirigid (malleable and mechanical) and inflatables. The AMS® (American Medical Systems) and Coloplast Ltd ® produce the majority of inflatable and semirigid devices.

Malleable and mechanical prostheses have the disadvantage that the penis is always erect although it can be orientated in different ways, while the advantages are ease of use and the need for a simpler surgical procedure compared with inflatable prostheses. Three-component prostheses are more sophisticated than semirigid devices. The advantages of these devices are that the prosthesis feels softer than semirigid or two-piece devices when deflated, with a better cosmetic result, and it ensures a more natural erection than others kinds of prosthesis. The disadvantages are the possibility of malfunction and the need for a more complicated surgical technique. Implantation of a penile prosthesis can be performed in a short surgical time under locoregional anaesthesia, and for this reason hospitalization is usually brief and the patient can be discharged 2 days after the operation if complications are not evident. Patient and partner satisfaction reflect the quality and the effectiveness of this treatment. Even though the results are positive in the vast majority of patients, the possibility of several complications makes penile prosthesis implantation a delicate kind of surgery. Complications can happen when the operation is carried out, in the peri-operative and in the postoperative period, and include infections, erosions of the prosthesis and mechanical failure in case of inflatable prosthesis. Penile prostheses available on the market have improved the success of this kind of surgery, thanks to the introduction of new materials and designs.
Collegiate athletes’ experience of the meaning of sport injury: A phenomenological investigation
Authors: Grindstaff Jason S , Wrisberg Craig A , Ross Jillian R
Published: February 2010

Aims: In this study, a phenomenological approach was used to gain an in-depth understanding of the meaning collegiate athletes derive from their injury experience. The integrated model of sport injury developed by Wiese-Bjornstal and colleagues1 served as the conceptual framework for the study.

Methods: Elite athletes ( n = 5) at one National Collegiate Athletic Association (NCAA) Division I university in the USA participated in phenomenological interviews at three different points post-injury and prior to return to participation in their respective sports. The first interview was conducted within seven days post-injury, while the second and third interviews were conducted 15—20 days post-injury and at least 30 days post-injury, respectively.

Results: Inductive analysis of the interview data revealed that while participants’ experiences varied somewhat and fluctuated over time, the meaning they derived from the experience was characterized by four major themes: perspective, emotion, coping and relationships. Subsequent deductive analysis indicated a modest fit of each athlete’s experience within the integrated model of sport injury and rehabilitation developed by Wiese-Bjornstal et al. 1

Conclusion: Participants’ psychological responses to sport injury were generally consistent with the Wiese-Bjornstal et al.1 model but the meaning of the experience was highly individualized and seemed to evolve over the course of the injury and rehabilitation process.
Review: Practical considerations in ovarian cancer chemotherapy
Authors: Cristea Mihaela , Han Ernest , Salmon Lennie , Morgan Robert J.
Published: February 2010

Epithelial ovarian cancer remains the most lethal gynecologic malignancy despite advances in treatment. The standard management generally involves a combination of surgical tumor debulking and chemotherapy. Over the decades, chemotherapy for ovarian cancer has evolved and currently involves a combination of intravenous platinum and taxane chemotherapy. Over the past decade, three randomized phase III trials have been reported, and all have demonstrated a significant survival advantage for intraperitoneal compared with intravenous chemotherapy. However, there are potential barriers and controversies related to the administration of intraperitoneal chemotherapy in ovarian cancer patients. In this review, we discuss the evolution and current management considerations of chemotherapy for the treatment of epithelial ovarian cancer.
A tailored lifestyle intervention to reduce the cardiovascular disease risk of individuals with Familial Hypercholesterolemia (FH): design of the PRO-FIT randomised controlled trial
Authors: Broekhuizen Karen , van Poppel Mireille NM , Koppes Lando LJ , Brug Johannes , van Mechelen Willem
Published: February 2010

Background

Because of a high cardiovascular disease (CVD) risk in people with Familial Hypercholesterolemia (FH), early prevention of cardiovascular disease is important for health gain and cost reduction. This project focuses on the development and evaluation of an innovative intervention aiming to reduce CVD risk by promoting a healthy lifestyle among people with FH.

Methods

This project is designed as a randomised controlled trial in which individuals with FH will be assigned randomly to a control or intervention group. In the intervention group (n = 200), participants will receive a personalized intervention which is a combination of web-based tailored lifestyle advice and personal counselling by a lifestyle coach. The control group (n = 200) will receive care as usual. Primary outcomes are biological indicators of CVD risk: systolic blood pressure, glucose, BMI, waist circumference and lipids (triglycerides, total, LDL and HDL cholesterol). Secondary outcomes are: healthy lifestyle behaviour (with regard to smoking, physical activity, dietary pattern and compliance to statin therapy) and psychological correlates and determinants of healthy lifestyle behaviour (knowledge, attitude, risk perception, social influence, self-efficacy, cues to action, intention and autonomy). Measurement will take place at baseline, and at 3 and 12 months after randomisation. Additionally, a throughout process-evaluation will be conducted to assess and monitor intervention implementation during the trial.

Discussion

Results of the PRO-FIT project will provide information about the effects and implementation of a healthy lifestyle intervention for individuals with FH. Our experiences with this intervention will be indicative about the suitability, feasibility and benefits of this approach for future interventions in other high-risk groups, such as Familial Combined Hypercholesterolemia (FCH) and diabetes.

Trial registration number

NTR1899
Laxative activities of Mareya micrantha (Benth.) Müll. Arg. (Euphorbiaceae) leaf aqueous extract in rats
Authors: Méité Souleymane , Bahi Calixte , Yéo Dodéhé , Datté Jacques Y , Djaman Joseph A , N'guessan David J
Published: February 2010

Background

Mareya micrantha(Benth.) Müll. Arg. (Euphorbiaceae) is a shrub that is commonly used in Côte d'Ivoire (West Africa) for the treatment of constipation and as an ocytocic drug. The present study was carried out to investigate the laxative activity ofMareya micranthain albino's Wistar rats.

Methods

Rats were divided in 5 groups of 5 animals each, first group as control, second group served as standard (sodium picosulfate) while group 3, 4 and 5 were treated with leaf aqueous extract ofMareya micranthaat doses of 100, 200 and 400 mg/kg body weight (b.w.),per osrespectively. The laxative activity was determined based on the weight of the faeces matter. The effects of the leaves aqueous extract ofMareya micranthaand castor oil were also evaluated on intestinal transit, intestinal fluid accumulation and ions secretion.

Results

Phytochemicals screening of the extract revealed the presence of flavonoids, alkaloids, tannins, polyphenols, sterols and polyterpenes. The aqueous extract ofMareya micranthaapplied orally (100, 200 and 400 mg/kg;p.o.), produced significant laxative activity and reduced loperamide induced constipation in dose dependant manner. The effect of the extract at 200 and 400 mg/kg (p.o.) was similar to that of reference drug sodium picosulfate (5 mg/kg,p.o). The same doses of the extract (200 and 400 mg/kg,p.o.) produced a significant increase (p < 0.01) of intestinal transit in comparison with castor oil (2 mL) (p < 0.01). Moreover, the extract induced a significant enteropooling and excretion of Cl-, Na+, K+and Ca2+in the intestinal fluid (p < 0.01).

Conclusions

The results showed that the aqueous extract ofMareya micranthahas a significant laxative activity and supports its traditional use in herbal medicine.
The effect of the COACH program (Continuity Of Appropriate pharmacotherapy, patient Counselling and information transfer in Healthcare) on readmission rates in a multicultural population of internal medicine patients
Authors: Karapinar-Çarkıt Fatma , Borgsteede Sander D , Zoer Jan , Siegert Carl , van Tulder Maurits , Egberts Antoine CG , van den Bemt Patricia MLA
Published: February 2010

Background

Medication errors occur frequently at points of transition in care. The key problems causing these medication errors are: incomplete and inappropriate medication reconciliation at hospital discharge (partly arising from inadequate medication reconciliation at admission), insufficient patient information (especially within a multicultural patient population) and insufficient communication to the next health care provider. Whether interventions aimed at the combination of these aspects indeed result in less discontinuity and associated harm is uncertain. Therefore the main objective of this study is to determine the effect of the COACH program (Continuity Of Appropriate pharmacotherapy, patient Counselling and information transfer in Healthcare) on readmission rates in patients discharged from the internal medicine department.

Methods/Design

An experimental study is performed at the internal medicine ward of a general teaching hospital in Amsterdam, which serves a multicultural population. In this study the effects of the COACH program is compared with usual care using a pre-post study design. All patients being admitted with at least one prescribed drug intended for chronic use are included in the study unless they meet one of the following exclusion criteria: no informed consent, no medication intended for chronic use prescribed at discharge, death, transfer to another ward or hospital, discharge within 24 hours or out of office hours, discharge to a nursing home and no possibility to counsel the patient.

The intervention consists of medication reconciliation, patient counselling and communication between the hospital and primary care healthcare providers.

The following outcomes are measured: the primary outcome readmissions within six months after discharge and the secondary outcomes number of interventions, adherence, patient's attitude towards medicines, patient's satisfaction with medication information, costs, quality of life and finally satisfaction of general practitioners and community pharmacists.

Interrupted time series analysis is used for data-analysis of the primary outcome. Descriptive statistics is performed for the secondary outcomes. An economic evaluation is performed according to the intention-to-treat principle.

Discussion

This study will be able to evaluate the clinical and cost impact of a comprehensive program on continuity of care and associated patient safety.

Trial registration

Dutch trial register: NTR1519
A signal amplification assay for HSV type 1 viral DNA detection using nanoparticles and direct acoustic profiling
Authors: Uludağ Yildiz , Hammond Richard , Cooper Matthew A
Published: February 2010

Background

Nucleic acid based recognition of viral sequences can be used together with label-free biosensors to provide rapid, accurate confirmation of viral infection. To enhance detection sensitivity, gold nanoparticles can be employed with mass-sensitive acoustic biosensors (such as a quartz crystal microbalance) by either hybridising nanoparticle-oligonucleotide conjugates to complimentary surface-immobilised ssDNA probes on the sensor, or by using biotin-tagged target oligonucleotides bound to avidin-modified nanoparticles on the sensor. We have evaluated and refined these signal amplification assays for the detection from specific DNA sequences of Herpes Simplex Virus (HSV) type 1 and defined detection limits with a 16.5 MHz fundamental frequency thickness shear mode acoustic biosensor.

Results

In the study the performance of semi-homogeneous and homogeneous assay formats (suited to rapid, single step tests) were evaluated utilising different diameter gold nanoparticles at varying DNA concentrations. Mathematical models were built to understand the effects of mass transport in the flow cell, the binding kinetics of targets to nanoparticles in solution, the packing geometries of targets on the nanoparticle, the packing of nanoparticles on the sensor surface and the effect of surface shear stiffness on the response of the acoustic sensor. This lead to the selection of optimised 15 nm nanoparticles that could be used with a 6 minute total assay time to achieve a limit of detection sensitivity of 5.2 × 10-12 M. Larger diameter nanoparticles gave poorer limits of detection than smaller particles. The limit of detection was three orders of magnitude lower than that observed using a hybridisation assay without nanoparticle signal amplification.

Conclusions

An analytical model was developed to determine optimal nanoparticle diameter, concentration and probe density, which allowed efficient and rapid optimisation of assay parameters. Numerical analysis and subsequent associated experimental data suggests that the response of the mass sensitive biosensor system used in conjunction with captured particles was affected by i) the coupled mass of the particle, ii) the proximal contact area between the particle and the sensor surface and iii) the available capture area on the particle and binding dynamics to this capture area. The latter two effects had more impact on the detection limit of the system than any potential enhancement due to added mass from a larger nanoparticle.
Lasers, stem cells, and COPD
Authors: Lin Feng , Josephs Steven F , Alexandrescu Doru T , Ramos Famela , Bogin Vladimir , Gammill Vincent , Dasanu Constantin A , De Necochea-Campion Rosalia , Patel Amit N , Carrier Ewa , Koos David R
Published: February 2010

The medical use of low level laser (LLL) irradiation has been occurring for decades, primarily in the area of tissue healing and inflammatory conditions. Despite little mechanistic knowledge, the concept of a non-invasive, non-thermal intervention that has the potential to modulate regenerative processes is worthy of attention when searching for novel methods of augmenting stem cell-based therapies. Here we discuss the use of LLL irradiation as a "photoceutical" for enhancing production of stem cell growth/chemoattractant factors, stimulation of angiogenesis, and directly augmenting proliferation of stem cells. The combination of LLL together with allogeneic and autologous stem cells, as well as post-mobilization directing of stem cells will be discussed.
Replication of avian, human and swine influenza viruses in porcine respiratory explants and association with sialic acid distribution
Authors: Van Poucke Sjouke GM , Nicholls John M , Nauwynck Hans J , Van Reeth Kristien
Published: February 2010

Background

Throughout the history of human influenza pandemics, pigs have been considered the most likely "mixing vessel" for reassortment between human and avian influenza viruses (AIVs). However, the replication efficiencies of influenza viruses from various hosts, as well as the expression of sialic acid (Sia) receptor variants in the entire porcine respiratory tract have never been studied in detail. Therefore, we established porcine nasal, tracheal, bronchial and lung explants, which cover the entire porcine respiratory tract with maximal similarity to the in vivo situation. Subsequently, we assessed virus yields of three porcine, two human and six AIVs in these explants. Since our results on virus replication were in disagreement with the previously reported presence of putative avian virus receptors in the trachea, we additionally studied the distribution of sialic acid receptors by means of lectin histochemistry. Human (Siaα2-6Gal) and avian virus receptors (Siaα2-3Gal) were identified with Sambucus Nigra and Maackia amurensis lectins respectively.

Results

Compared to swine and human influenza viruses, replication of the AIVs was limited in all cultures but most strikingly in nasal and tracheal explants. Results of virus titrations were confirmed by quantification of infected cells using immunohistochemistry. By lectin histochemistry we found moderate to abundant expression of the human-like virus receptors in all explant systems but minimal binding of the lectins that identify avian-like receptors, especially in the nasal, tracheal and bronchial epithelium.

Conclusions

The species barrier that restricts the transmission of influenza viruses from one host to another remains preserved in our porcine respiratory explants. Therefore this system offers a valuable alternative to study virus and/or host properties required for adaptation or reassortment of influenza viruses. Our results indicate that, based on the expression of Sia receptors alone, the pig is unlikely to be a more appropriate mixing vessel for influenza viruses than humans. We conclude that too little is known on the exact mechanism and on predisposing factors for reassortment to assess the true role of the pig in the emergence of novel influenza viruses.
Mild hypothermia alone or in combination with anesthetic post-conditioning reduces expression of inflammatory cytokines in the cerebral cortex of pigs after cardiopulmonary resuscitation
Authors: Meybohm Patrick , Gruenewald Matthias , Zacharowski Kai D , Albrecht Martin , Lucius Ralph , Fösel Nikola , Hensler Johannes , Zitta Karina , Bein Berthold
Published: February 2010

Introduction

Hypothermia improves survival and neurological recovery after cardiac arrest. Pro-inflammatory cytokines have been implicated in focal cerebral ischemia/reperfusion injury. It is unknown whether cardiac arrest also triggers the release of cerebral inflammatory molecules, and whether therapeutic hypothermia alters this inflammatory response. This study sought to examine whether hypothermia or the combination of hypothermia with anesthetic post-conditioning with sevoflurane affect cerebral inflammatory response after cardiopulmonary resuscitation.

Methods

Thirty pigs (28 to 34 kg) were subjected to cardiac arrest following temporary coronary artery occlusion. After seven minutes of ventricular fibrillation and two minutes of basic life support, advanced cardiac life support was started according to the current American Heart Association guidelines. Return of spontaneous circulation was achieved in 21 animals who were randomized to either normothermia at 38°C, hypothermia at 33°C or hypothermia at 33°C combined with sevoflurane (each group: n = 7) for 24 hours. The effects of hypothermia and the combination of hypothermia with sevoflurane on cerebral inflammatory response after cardiopulmonary resuscitation were studied using tissue samples from the cerebral cortex of pigs euthanized after 24 hours and employing quantitative RT-PCR and ELISA techniques.

Results

Global cerebral ischemia following resuscitation resulted in significant upregulation of cerebral tissue inflammatory cytokine mRNA expression (mean ± SD; interleukin (IL)-1β 8.7 ± 4.0, IL-6 4.3 ± 2.6, IL-10 2.5 ± 1.6, tumor necrosis factor (TNF)α 2.8 ± 1.8, intercellular adhesion molecule-1 (ICAM-1) 4.0 ± 1.9-fold compared with sham control) and IL-1β protein concentration (1.9 ± 0.6-fold compared with sham control). Hypothermia was associated with a significant (P < 0.05 versus normothermia) reduction in cerebral inflammatory cytokine mRNA expression (IL-1β 1.7 ± 1.0, IL-6 2.2 ± 1.1, IL-10 0.8 ± 0.4, TNFα 1.1 ± 0.6, ICAM-1 1.9 ± 0.7-fold compared with sham control). These results were also confirmed for IL-1β on protein level. Experimental settings employing hypothermia in combination with sevoflurane showed that the volatile anesthetic did not confer additional anti-inflammatory effects compared with hypothermia alone.

Conclusions

Mild therapeutic hypothermia resulted in decreased expression of typical cerebral inflammatory mediators after cardiopulmonary resuscitation. This may confer, at least in part, neuroprotection following global cerebral ischemia and resuscitation.
Maternal Dietary Fat Determines Metabolic Profile and the Magnitude of Endocannabinoid Inhibition of the Stress Response in Neonatal Rat Offspring
Authors: D'Asti Esterina , Long Hong , Tremblay-Mercier Jennifer , Grajzer Magdalena , Cunnane Stephen C. , Di Marzo Vincenzo , Walker Claire-Dominique
Published: February 2010

Endocannabinoids (eCBs) are products of phospholipid (PL)-derived arachidonic acid (AA) that regulate hypothalamus-pituitary-adrenal axis activity. We hypothesized that differences in the quality and quantity of maternal dietary fat would modulate the PL AA content in the neonatal brain affecting stress responsiveness via differences in eCB production and activity in stress-activated brain areas. Pregnant rats were fed a 5% [control (C)] or 30% fat [high fat (HF)] diet rich in either n-6 (HF-n-6) or n-3 (HF-n-3) fat during the last week of gestation and lactation. Postnatal d 10 offspring were tested for metabolic hormones, AA (n-6) and eCB brain content, and hormonal effects of eCB receptor antagonism (AM251, 1 or 3 mg/kg ip) on stress responses. Like maternal diet, milk from HF-n-3 mothers had a reduced n-6/n-3 fat ratio compared with that of C and HF-n-6 mothers. Hypothalamic and hippocampal levels of PL AA were diet specific, reflecting the maternal milk and dietary n-6/n-3 ratio, with HF-n-3 offspring displaying reduced AA content relative to C and HF-n-6 offspring. Plasma corticosterone and insulin were elevated in HF-fed pups, whereas leptin was increased only in HF-n-6 pups. Basal eCB concentrations were also diet and brain region specific. In C pups, eCB receptor antagonist pretreatment increased stress-induced ACTH secretion, but not in the HF groups. Stress-induced corticosterone secretion was not sensitive to AM251 treatment in HF-n-3 pups. Thus, the nature of preweaning dietary fat differentially influences neonatal metabolic hormones, brain PL AA levels, and eCB, with functional consequences on hypothalamus-pituitary-adrenal axis modulation in developing rat pups.
Risky Business: Effectiveness of State Market-Based Health Programs
Authors: Stream Christopher , Myers Nathan
Published: February 2010

Since the 1990s, state governments have been leaders of health care reform. Today, approximately 47 million people are without health insurance. As health care costs and uninsurance levels continue to rise, states are pursuing a variety of government- and market-based strategies to address this growing social problem. Health care research has indicated that state-based programs have proven to be successful in extending access to coverage. However, the question remains as to whether the market-based programs have had a positive impact on state health care. Advocates for market-based state health programs argue that the reforms benefit the greater good because they serve an economic development function by improving the economic productivity and overall health of state citizens. Whether market-based policies are accomplishing these goals is a matter of debate. This study examines the effects of the various market-based state policies. The evidence generated by this research sheds light on the societal effectiveness of market-based health care strategies used by state governments. The results of our analysis indicate that programs enacted by states to promote increased access to medical care have developmental effects beyond the client population directly served.
Measuring Coverage for Seniors in Medicare Part A and Estimating the Cost of Making It Universal
Authors: Birnbaum Michael , Patchias Elizabeth M.
Published: February 2010

That Medicare is universal for seniors is widely accepted by leading analysts. But in the context of developing detailed policies that seek to cover as many people as possible, it is inaccurate to make Medicare eligibility sound so simple and inclusive. To estimate the number of seniors without full federal Medicare Part A coverage, we examined data for uninsured seniors, seniors with Medicaid and no Medicare coverage of any kind, seniors with Medicare Part B but without Part A, and seniors bought into Part A by their state Medicaid programs. We found that in 2005, 1.6 million seniors—or 5 percent of the elderly U.S. population—were without a full federal Part A premium subsidy. The share of seniors without this benefit was notably higher in the nation's two largest states—California (12 percent) and New York (8 percent). We estimate that reforming Medicare Part A to make the benefit truly universal and fully federal would cost the federal government $6 billion in new spending in federal fiscal year 2011, an increase in baseline federal Medicare expenditures of 1.1 percent.
Nurses and Hospitals—together, and Not
Authors: Koetting Mike
Published: February 2010

Two recent books about how hospitals are organized illustrate the essential tension over a fundamental dynamic of society. Safety in Numbers argues that an indispensible element of hospital patient safety is mandated nurse-to-patient ratios and that those will be achieved only when nurses force the change on hospitals. Hospital, on the other hand, is a journalistic account of one hospital; while acknowledging elements of conflict, it suggests that shared vision and workplace bonds are what hold together at least this particular hospital. What emerges from both works is a sense that the business of operating hospitals tends to be a very human one that typically achieves results through rather messy processes. These lines of thought are crucial as the nation contemplates what it really wants in its health care system—and how on earth to achieve it.
A Rolls-Royce Corporation industrial perspective of titanium process modelling and optimization: Current capabilities and future needs
Authors: Glavicic M G , Furrer D U , Shen G
Published: February 2010

A focused review on modelling and simulation of several key titanium features is presented with the intent to provide a broad overview of the titanium modelling efforts being worked on in academia and the industrial sector.
Coupling of dynamics and contact mechanics of artificial hip joints in a pendulum model
Authors: Liu H , Ellison P J , Xu H , Jin Z
Published: February 2010

To date, fully coupled dynamics and contact mechanics analysis is still limited by expensive computational cost and long computing time and has not been addressed comprehensively, particularly in the hip joint. To understand the influence of different parameters on the biomechanics of the total hip replacement (THR) and improve its design, two numerical approaches were developed and implemented in finite element models to investigate the coupling between the dynamics response and the contact mechanics for three different THR configurations, metal-on-polyethylene (MOP), metal-on-metal (MOM), and ceramic-on-ceramic (COC). The dynamic force and the contact pressure distribution at the bearing surfaces from the two methods were predicted and compared. The influences of various parameters (motion angle, load applied in the pendulum, friction coefficient, geometry, and material properties) were subsequently investigated. From the comparisons, the decoupled method, based on the rigid-body dynamics and the quasi-static elastic contact mechanics, was adequate to predict the performance of the THRs efficiently. The load had the greatest influence on the dynamics/contact mechanics among other factors.
A review of probabilistic analysis in orthopaedic biomechanics
Authors: Laz P J , Browne M
Published: February 2010

Probabilistic analysis methods are being increasingly applied in the orthopaedics and biomechanics literature to account for uncertainty and variability in subject geometries, properties of various structures, kinematics and joint loading, as well as uncertainty in implant alignment. As a complement to experiments, finite element modelling, and statistical analysis, probabilistic analysis provides a method of characterizing the potential impact of variability in parameters on performance. This paper presents an overview of probabilistic analysis and a review of biomechanics literature utilizing probabilistic methods in structural reliability, kinematics, joint mechanics, musculoskeletal modelling, and patient-specific representations. The aim of this review paper is to demonstrate the wide range of applications of probabilistic methods and to aid researchers and clinicians in better understanding probabilistic analyses.
Influence of particle size, applied load, and fibre orientation on 3B-A wear and frictional behaviour of epoxy composite based on kenaf fibres
Authors: Chin C W , Yousif F
Published: February 2010

The current work aims to investigate the effect of sand particle size, applied load, and kenaf fibre orientation on the three-body abrasion wear behaviour of epoxy composite subjected to high stress. Experiments were conducted using a dry sand/steel wheel apparatus at different applied loads (5-20 N). The tests were performed at a rotational speed of 100 rpm (corresponding to 1.152 m/s) for 300 s test duration. The sizes of the sand particles were 370-390 μm, 650-750 μm, and 1200-1400 μm with a fixed flowrate of 4.5 g/s. The composite was tested in three different orientations, namely parallel, anti-parallel, and normal (P-O, AP-O, and N-O). Scanning electron microscopy was used to observe the damage features on the worn surfaces of the composite. The results revealed that the fibre orientation highly influenced the wear and frictional behaviour of the composite. In N-O, the wear and frictional performance were better when compared to the other orientations. The wear mechanism was predominated by detachment and breakage of fibres, fracture, and defragmentation in the epoxy regions when the composite was tested in P- and AP-O. Meanwhile, micro-cracks on the end of the fibres are the pronounced wear mechanism in the KFRE tested in N-O.
Generation and prediction methods for circumferential distribution changes in the braiding angle on a cylindrical braided fabric
Authors: Nishimoto H , Ohtani A , Nakai A , Hamada H
Published: February 2010

Braided composites have an advantage in that their stiffness distribution can be changed by changing the orientation angle of the fibre bundle, called the ‘braiding angle’. To change the braiding angle on a cylindrical braided fabric, the longitudinal velocity of the mandrel and the angular rate of the spindle in a braider should be changed. However, these changes are only in the longitudinal direction and not in the circumferential direction.

A method for generating changes in the circumferential direction is proposed. The method sets an elliptical guide ring to provide fibres towards the longitudinal direction, called the ‘creating ellipse’, rather than a circular guide ring, called the ‘creating circle’ on a braider. Dynamic changes in the radius of the creating ellipse induce distribution changes in the circumferential direction. In validation studies comparing theoretical braiding angles with the experimental results, this method is proven effective for predicting circumferential distributions on a cylindrical braided fabric.
High Performance of Si–O–Ti Bonds for Anchoring Sensitizing Dyes on TiO2 Electrodes in Dye-sensitized Solar Cells Evidenced by Using Alkoxysilylazobenzenes
Authors: Kakiage Kenji , Yamamura Masaki , Fujimura Emi , Kyomen Toru , Unno Masafumi , Hanaya Minoru
Published: February 2010

Applicability of alkoxysilyl group was examined for the first time as the anchor moiety of sensitizing dyes for dye-sensitized solar cells by using alkoxysilylazobenzenes. Alkoxysilylazobenzenes adsorbed efficiently onto TiO2 electrodes by the formation of Si–O–Ti bonds, and the electrodes exhibited much higher durability to water and better photovoltaic performance than in the case of a conventional carboxy dye.
Mental Retirement
Authors: Rohwedder Susann , Willis Robert J
Published: February 2010

Early retirement appears to have a significant negative impact on the cognitive ability of people in their early 60s that is both quantitatively important and causal. We obtain this finding using cross-nationally comparable survey data from the United States, England, and Europe that allow us to relate cognition and labor force status. We argue that the effect is causal by making use of a substantial body of research showing that variation in pension, tax, and disability policies explain most variation across countries in average retirement rates. (In an informal manner, we are arguing that public policies that affect the age of retirement may be used as instrumental variables to generate cross-country variation in retirement behavior in order to identify the causal effect of retirement on cognition.)
Did Fair-Value Accounting Contribute to the Financial Crisis?
Authors: Laux Christian , Leuz Christian
Published: February 2010

The recent financial crisis has led to a major debate about fair-value accounting. Many critics have argued that fair-value accounting, often also called mark-to-market accounting, has significantly contributed to the financial crisis or, at least, exacerbated its severity. In this paper, we assess these arguments and examine the role of fair-value accounting in the financial crisis using descriptive data and empirical evidence. Based on our analysis, it is unlikely that fair-value accounting added to the severity of the 2008 financial crisis in a major way. While there may have been downward spirals or asset-fire sales in certain markets, we find little evidence that these effects are the result of fair-value accounting. We also find little support for claims that fair-value accounting leads to excessive write-downs of banks' assets. If anything, empirical evidence to date points in the opposite direction, that is, toward the overvaluation of bank assets during the crisis.