cssi/SciSciGPT-SciSciNet huggingface dataset:
Enhancing backup protection for thermal power generating stations using sampled values

Evaluation of relay misoperations provides an opportunity to improve the design of backup protection schemes. Existing generator station backup protection schemes use distance protection (21) or voltage controlled/restrained overcurrent protection (51V) elements for clearing phase faults that are not cleared by either line protection or generator protection. Many schemes also use transformer ground overcurrent protection (51NG) for backup protection for ground faults on the system. Since generator protection can only respond to faults with fault resistance accurately when only there is no remote infeed from the other terminals, designing a secure backup protection for a generating station during remote infeed conditions is a challenge. Apart from the remote infeed, fast response of automatic excitation controllers also affects the current seen by the generator protection relay. Considering these effects, different vendors have different approaches for setting the 21 element. In order to analyze these recommendations, this paper studies the performance of synchronous generators for a thermal power station connected through a breaker and half scheme using Real Time Digital Simulator (RTDS) simulations. This paper proposes a new approach to enhance the performance and coverage of backup protection schemes by using sampled values of the IEC 61850 standard. In addition to that, this paper also address the challenges associated with the existing generator protection schemes based on breaker auxiliary contacts and under current elements and proposes a solution using a synchronism check element which uses sampled values. These two techniques can be used in the existing generating station protection schemes to improve the reliability and security of these schemes.
Multivariate Prognostic Model of Acute Stroke Combining Admission Infarct Location and Symptom Severity: A Proof-of-Concept Study

Background The information on topographic distribution of acute ischemic infarct can contribute to prediction of functional outcome. We aimed to develop a multivariate model for stroke prognostication, combining admission clinical and imaging variables, including the infarct topology. Methods Acute ischemic stroke patients without baseline functional disability who had magnetic resonance imaging within 24 hours of onset or last-seen-well were included. The admission stroke severity was determined using the National Institutes of Health Stroke Scale (NIHSS) score. The relation between infarct location and outcome was assessed using both voxel-based and visual atlas-based analyses. The disability/death was defined by a modified Rankin Scale score greater than 2 at 3-month follow-up. Results Among 198 patients included in this study, higher admission NIHSS score (P Conclusions Admission symptom severity, infarction of insula, and midbrain/pons were independent predictors of clinical outcome in acute ischemic stroke patients. The methodology of this hypothesis-generating study can help conceive quantitative population-based probabilistic models for prognostication or treatment triage in stroke patients, combining admission clinical and imaging findings—including infarct topography.
Evaluation of Prognosis in Hormone Receptor-Positive/HER2-Negative and Lymph Node-Negative Breast Cancer With Low Oncotype DX Recurrence Score.

Abstract Introduction Hormone receptor–positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancers without lymph node metastasis have good prognosis. We compared the prognosis of hormone receptor–positive, HER2-negative, lymph node–negative cancers with Oncotype DX score ranges of 1 to 10 (1-10 group) and 11 to Patients and Methods A total of 107 cases in the 1-10 group and 225 cases in the 11-18 group were reviewed. All patients received surgery. The use of chemotherapy, radiotherapy, and endocrine therapy, and overall survival (OS), disease-free survival (DFS), and distant metastasis were compared between groups. Results There were no statistical differences in the use of chemotherapy (5.05% vs. 6.05%, P = .724) or radiotherapy (52.53% vs. 59.07%, P = .276) between the 1-10 group and the 11-18 group, respectively. The median OS and DFS were 47 and 45 months, respectively, in the 1-10 group, and 49 and 48 months in the 11-18 group. No significant difference was seen in OS (P = .995), DFS (P = .148), or rates of metastasis (P = .998). The 11-18 group had more death events and distant metastasis (death, 5 events; recurrence, 2 events; metastasis, 2 events) than the 1-10 group (death, 0 events; recurrence, 4 events; metastasis, 0 events). The majority of recurrences seen in both groups were in young patients who failed to comply with their endocrine therapy regimen. Conclusion Patients in both the 1-10 group and the 11-18 group had good prognoses. Those who experienced recurrence were more likely to be premenopausal and to have failed to comply with the recommended endocrine therapy regimen. Endocrine therapy remains important in these patients.
Quantifying growth of cold-adapted Listeria monocytogenes and Listeria innocua on fresh spinach leaves at refrigeration temperatures

Abstract The Baranyi model was used to obtain the initial cell concentration, yo, lag time, tlag, maximum cell concentration, ymax, and maximum growth rate, μmax, using data collected on the growth of cold-adapted (CA) Listeria monocytogenes and Listeria innocua on fresh spinach leaves under refrigeration temperatures (3, 5, and 8 °C). For L. monocytogenes, a dynamic model was validated for ymax, tlag, and μmax. Although L. monocytogenes grew on the leaves at all refrigeration temperatures, L. innocua did not show growth at 3 °C. At 5 and 8 °C, the growth parameters (tlag and ymax) for L. monocytogenes and L. innocua were significantly different (P
Declining ambient water phosphorus concentrations in Massachusetts’ rivers from 1999 to 2013: Environmental protection works

Over the last century, nutrient concentrations in streams, rivers, lakes and ponds have increased substantially in the United States. Elevated phosphorus levels are a concern due to their ability to cause changes in freshwater ecosystems that are detrimental to humans and wildlife. In the present study, long-term trends in total phosphorus (TP) concentrations from 20 rivers in central Massachusetts from 1999 to 2013 were investigated. Kendall's correlation coefficients were used to demonstrate that 18 of the 20 rivers had significant reductions in TP concentrations (P 0.1 mg/L. TP decreases were greater in rivers with more anthropogenic inputs. Principal component analysis (PCA) revealed that the decline of TP in these Massachusetts streams is likely the result of advancements in wastewater treatment and implementation of effective non-point source management practices.
Examining Workflow in a Pediatric Emergency Department to Develop a Clinical Decision Support for an Antimicrobial Stewardship Program

Background Clinical decision support (CDS) embedded into the electronic health record (EHR), is a potentially powerful tool for institution of antimicrobial stewardship programs (ASPs) in emergency departments (EDs). However, design and implementation of CDS systems should be informed by the existing workflow to ensure its congruence with ED practice, which is characterized by erratic workflow, intermittent computer interactions, and variable timing of antibiotic prescription. Objective This article aims to characterize ED workflow for four provider types, to guide future design and implementation of an ED-based ASP using the EHR. Methods Workflow was systematically examined in a single, tertiary-care academic children's hospital ED. Clinicians with four roles (attending, nurse practitioner, physician assistant, resident) were observed over a 3-month period using a tablet computer-based data collection tool. Structural observations were recorded by investigators, and classified using a predetermined set of activities. Clinicians were queried regarding timing of diagnosis and disposition decision points. Results A total of 23 providers were observed for 90 hours. Sixty-four different activities were captured for a total of 6,060 times. Among these activities, nine were conducted at different frequency or time allocation across four roles. Moreover, we identified differences in sequential patterns across roles. Decision points, whereby clinicians then proceeded with treatment, were identified 127 times. The most common decision points identified were: (1) after/during examining or talking to patient or relative; (2) after talking to a specialist; and (3) after diagnostic test/image was resulted and discussed with patient/family. Conclusion The design and implementation of CDS for ASP should support clinicians in various provider roles, despite having different workflow patterns. The clinicians make their decisions about treatment at different points of overall care delivery practice; likewise, the CDS should also support decisions at different points of care.
Rethinking public institutions in India

With a few notable exceptions, India’s formal public institutions have attracted relatively little systematic attention. The edited collection Rethinking public institutions in India, along with it...
Trunk Control in Children with Cerebral Palsy and its Association with Upper Extremity Functions

This study investigated the upper extremity functions of children with Cerebral Palsy (CP) and the association between upper extremity function and trunk control. Thirty children with unilateral CP and 32 children with bilateral CP between the ages of 5 and 12 years were included in this study. The Trunk Control Measurement Scale (TCMS) was used to assess trunk control, and the Quality of Upper Extremity Skills Test was used to assess upper extremity functions (QUEST) (QUEST consists of four subscales: Dissociated Movements Scale, Grasp Scale, Weight Bearing Scale, and Protective Extension Scale). There was a significant difference between the unilateral and bilateral CP groups, with unilateral CP favored in terms of trunk control. There was no difference in QUEST total scores between the unilateral and bilateral CP groups (p < 0.05). In both groups, there was a significant correlation between the total TCMS score and the Dissociated Movements Scale, Grasp Scale, Weight Bearing Scale and QUEST total score (p < 0.05). There was a significant positive correlation between trunk control and upper extremity functions in children with CP. This relationship must be considered for the effective implementation of physiotherapy assessment and intervention.
A recursive sparse blind source separation method for nonnegative and correlated data in NMR spectroscopy

Motivated by the nuclear magnetic resonance (NMR) spectroscopy of biofluids (urine and blood serum), we present a recursive blind source separation (rBSS) method for nonnegative and correlated data. A major approach to non-negative BSS relies on a strict nonoverlap condition (also known as the pixel purity assumption in hyperspectral imaging) of source signals which is not always guaranteed in the NMR spectra of chemical compounds. A new dominant interval condition is proposed. Each source signal dominates some of the other source signals in a hierarchical manner. The rBSS method then reduces the BSS problem into a series of sub-BSS problems by a combination of data clustering, linear programming, and successive elimination of variables. In each sub-BSS problem, an l1 minimization problem is formulated for recovering the source signals in a sparse transformed domain. The method is substantiated by NMR data.
Time stability of delta-radiomics features and the impact on patient analysis in longitudinal CT images.

Purpose This study first aims to show that the values of texture features extracted from phantoms are stable over clinical timescales. Second, that changes in patients' feature values over the course of radiation therapy (RT) are treatment induced and statistically significant. Methods The CT datasets of a 3D printed anatomically informed texture phantom containing liver and low-contrast modules, and the homogeneous module of the Catphan 500-Series phantom, were acquired once per week over the course of a 6-week period, to simulate the timescale of conventional RT duration. A Definition AS Open CT scanner on rails (Siemens) and our institution's standard abdominal protocol were used. In each phantom module, 8 regions of interest (20 cm 3 ) were selected and 50 texture features were extracted from each module over the longitudinal dataset. The time stability of each feature was evaluated. The expected variation over the treatment timescale was quantified for each texture (module). Subsequently, the pancreas heads of 10 patients who underwent RT for adenocarcinoma of the pancreas head with a pathologic response of at least "moderate" (grade 2), were contoured on the daily CTs acquired using the same scanner. The pancreas heads were contoured on one image per week. Mean CT number, skewness, kurtosis, and coarseness were extracted from these data. The phantom modules were shown to be accurate representations of these features in the pancreas data. The change in the feature value between fractions 2 and 26 was compared with the phantom data in order to identify significant changes in feature value. Results Of the 50 features examined in all 3 phantom modules, 47 were found to have zero time-trend when a fit assuming homogeneous variance was used. When a fit allowing for heterogeneous variance was used, 49 features were found to have zero time-trend. Features were stable and repeatable within a feature-specific confidence interval over the 6-week period of acquisition in all three phantom modules. Changes in feature value between fractions 2 and 26 were highly patient specific. Mean CT number was found to decrease significantly in 7 of 10 patients and increase significantly in one patient. Skewness increased significantly in one patient and decreased significantly in one patient. Kurtosis decreased significantly in four patients and increased significantly in one patient. Coarseness increased significantly in seven patients and decreased significantly in one patient. Only one patient experienced no significant changes in feature value. Conclusion The CT texture feature measurements of phantoms are stable and repeatable within a feature-specific confidence interval in all three phantom modules. This suggests that the changes observed in features extracted from longitudinal patient CT data may be treatment induced, and demonstrates their potentiality for early assessment of treatment response.
Dynamic Programming Algorithms for Haplotype Block Partitioning and Tag SNP Selection Using Haplotype Data or Genotype Data

Recent studies have revealed that the human genome can be decomposed into large blocks with high linkage disequilibrium (LD) and relatively limited haplotype diversity, separated by short regions of low LD. One of the practical implications of this observation is that only a small number of tag SNPs are needed for mapping genes responsible for human complex diseases, which can significantly reduce genotyping effort without much loss of power. In this paper, we survey the dynamic programming algorithms developed for haplotype block partitioning and tag SNP selection, with a focus on algorithmic considerations. Extensions of the algorithms for analysis of genotype data from unrelated individuals as well as genotype data from general pedigrees are considered. Finally, we discuss the implications of haplotype blocks and tag SNPs in association studies to search for complex disease genes.
Machine Learning Aided Design and Analysis of a Novel Magnetically Coupled Ball Drive

Mobile robotic platforms navigating in unstructured and dynamic environments greatly benefit from unconstrained omnidirectional locomotion. Ground robots with spherical wheels (ball-driven robots) can enable agile omnidirectional mobility over a wide range of ground terrains. Slip occurrence at the drive and ground contact surfaces decreases actuation performance, especially during rapid vehicle acceleration and navigation on graded terrains. In this paper, the design of a new magnetically coupled ball drive that uses controllable magnetic forces to increase the transmittable actuation torque and improve traction performance is described. The design uses an internal support structure to magnetically couple the spherical wheel to the chassis enabling it to function as an omnidirectional axel. Using a model of the magnetically coupled ball drive, the slip/no-slip operational window of the new design is evaluated. A support vector classification machine is trained to classify the slip/no-slip regions and identify the relative importance scores of the feature parameters in order of their sensitivity. The classification provided insight into appropriate ranges of the critical parameters that can improve traction performance. Based on the classification of the design space, multiple design and operational points were obtained to guide the design process further. Magnetostatic simulations are then used to design space efficient magnetic arrays capable of generating coupling forces in the desired range. A prototype of the new ball drive design is developed, and the premise that the magnetically coupled ball drive can improve the slip performance is experimentally tested. The results show that it is possible to control the traction forces at both drive and ground surfaces using the magnetic coupling force and substantially increase the slip performance of the ball drive using the new design.
Collocation for Supplier–Client Knowledge-Based Coordination: Niche Positioning, Task Complexity, and Comparative Costs

We examine how clients and suppliers govern vertical relationships for knowledge work. Collocation—having supplier personnel interact with the client’s personnel and systems at the client’s site—is a contractual mechanism that facilitates coordination for knowledge co-creation. Using a sample of 1609 credit unions’ relationships with 50 IT suppliers during the rise of Internet-based banking from 2000 to 2004, we examine the initial development of arrangements for online share account and loan processing. Results show that client positioning and task complexity partially determined the choice of collocation vis-a-vis a supplier delivering standard services from a remote location. However, as broadband communications reduced the costs of remote service, clients moved away from collocation.
Environmental Turbulence and Scanning Behavior: The Moderating Effects of Organizational Maturity

This paper examines the relationship between environmental turbulence and information scanning behavior in a sample of 242 small and medium-sized enterprises (SMEs), and the moderating effects of organizational age. Our results suggest that SME decision makers utilize a selective, cognitive simplification process in their information search activities. Scanning behavior of SMEs is highly differentiated and very selective in the face of turbulent task environments. In general, our sampled SMEs seem to be more attuned to technological and competitive turbulence. Additionally, young and mature SMEs also exhibit different scanning behaviors. While young SMEs prefer a search mode of proactive continuous internal gathering, mature SMEs opt for a mode of reactive internal and external information gathering. Implications of this study are discussed.
Growth Failure and Feeding Difficulties: Guidelines for Enteral and Parenteral Nutrition

Nutrition support is a fundamental aspect of care for critically ill pediatric cardiac patients, with known effects on morbidity, wound healing, infection, and length of hospitalization. Provision of adequate nutrition support presents several unique challenges in the pediatric cardiac population. Pediatric patients hospitalized with congenital heart disease are usually born at normal weight but rapidly develop malnutrition (undernutrition). In fact, nearly half of children admitted for cardiac surgery are malnourished. Risk factors for preoperative growth failure in these patients include; the underlying cardiac physiology, the presence or absence of congestive heart failure, anorexia, poor oral feeding coordination, gastrointestinal abnormalities or dysfunction, and the presence or absence of genetic disease. Infants with single ventricle physiology are at particular risk for malnutrition, which is known to increase their risk for interstage mortality. Many of these children experience malabsorption due to decreased cardiac output, hypoxia, elevated right-sided cardiac pressure, and subsequent gastrointestinal dysfunction. Infants and children undergoing cardiac surgery may go on to develop further deterioration of their nutrition status due to postoperative fluid restrictions, interruptions to feeding for procedures, feeding intolerance, and delays initiating enteral nutrition due to provider concern for gastrointestinal complications of early postoperative enteral nutrition, such as necrotizing enterocolitis. Acute malnutrition that develops postoperatively further increases the risk of poor outcomes after surgical repair or palliation of congenital heart disease. Interstage monitoring programs for children with single ventricle physiology focus on screening for malnutrition and assessment of nutrition status, enteral nutrition interventions targeted to maintain normal growth, dietician care, and family engagement. Interstage monitoring programs are associated with improved malnutrition indices and with improved outcomes, including improved survival.
Performance validity assessment using response time on the Warrington Recognition Memory Test.

Objective The present study tested the incremental utility of response time (RT) on the Warrington Recognition Memory Test - Words (RMT-W) in classifying bona fide versus feigned TBI. Method Participants were 173 adults: 55 with moderate to severe TBI, 69 healthy comparisons (HC) instructed to perform their best, and 49 healthy adults coached to simulate TBI (SIM). Participants completed a computerized version of the RMT-W in the context of a comprehensive neuropsychological battery. Groups were compared on RT indices including mean RT (overall, correct trials, incorrect trials) and variability, as well as the traditional RMT-W accuracy score. Results Several RT indices differed significantly across groups, although RMT-W accuracy predicted group membership more strongly than any individual RT index. SIM showed longer average RT than both TBI and HC. RT variability and RT for incorrect trials distinguished SIM-HC but not SIM-TBI comparisons. In general, results for SIM-TBI comparisons were weaker than SIM-HC results. For SIM-HC comparisons, classification accuracy was excellent for all multivariable models incorporating RMT-W accuracy with one of the RT indices. For SIM-TBI comparisons, classification accuracies for multivariable models ranged from acceptable to excellent discriminability. In addition to mean RT and RT on correct trials, the ratio of RT on correct items to incorrect items showed incremental predictive value to accuracy. Conclusion Findings support the growing body of research supporting the value of combining RT with PVTs in discriminating between verified and feigned TBI. The diagnostic accuracy of the RMT-W can be improved by incorporating RT.
Helping children with disabilities combat negative socio-emotional outcomes caused by bullying through extracurricular activities

Past studies have indicated students who have disabilities are at a higher risk of experiencing bullying victimization in comparison to other student groups. Extracurricular activity participation ...
Emergent Warfarin Reversal With Fixed-Dose 4-Factor Prothrombin Complex Concentrate.

Background:Four-factor prothrombin complex concentrate (4FPCC) is used for emergent warfarin reversal, but dosing remains controversial. Following approval, further studies have evaluated a variety...
The prism manifold realization problem

The spherical manifold realization problem asks which spherical three-manifolds arise from surgeries on knots in S3. In recent years, the realization problem for C–, T–, O– and I–type spherical manifolds has been solved, leaving the D–type manifolds (also known as the prism manifolds) as the only remaining case. Every prism manifold can be parametrized as P(p,q) for a pair of relatively prime integers p>1 and q. We determine a list of prism manifolds P(p,q) that can possibly be realized by positive integral surgeries on knots in S3 when q<0. Based on the forthcoming work of Berge and Kang, we are confident that this list is complete. The methodology undertaken to obtain the classification is similar to that of Greene for lens spaces.
Intensive Outpatient Program Using Prolonged Exposure for Combat-Related PTSD: A Case Study

Abstract Although prolonged exposure (PE) has been identified as a first-line treatment for posttraumatic stress disorder (PTSD), research has found that military service members and veterans have smaller reductions in symptom severity compared to civilians. The nature of trauma in a deployed combat setting and the unique complexities of military culture have been proposed as explanations for greater rates of PTSD and poorer treatment response to first-line psychotherapies in military and veteran populations. This paper presents a case study to highlight how a novel, intensive outpatient program utilizing prolonged exposure therapy (IOP-PE) may benefit military personnel with combat-related PTSD. The patient is a Caucasian man in his early 40s seeking treatment for PTSD after more than 10 years of enlisted, active duty military service across two branches and three combat deployments. The IOP-PE includes the standard PE components and eight, nonstandard treatment augmentations tailored for military personnel. In contrast to standard PE, which typically is delivered weekly over several months, IOP-PE consists of 15 daily, 90-minute PE sessions conducted over 3 weeks. The patient demonstrated large reductions on the Clinician-Administered PTSD Scale (28 points) and PTSD Checklist (48 points) by the 6-month posttreatment follow-up point. Findings provide support for conducting further research that determines whether IOP-PE is effective and tolerable in military and veteran populations.
Editorial: The Present and Future of Immunology Education.

This Research Topic addresses issues relevant to teaching of modern immunology, a field that has exploded in recent years and is constantly evolving. These articles encompass curricular innovation, new pedagogical strategies, and teaching tools for the current and future generations of immunologists. The wide range of articles in this Research Topic illustrate diverse approaches for teaching basic tenets of immunology. Fortunately, immunologists are well-acquainted with diversity. Channeling one of the basic principles of Immunology, it is hoped the readers of this issue will select the Immunology articles that are most helpful to their particular mode of teaching. The articles presented are aimed at practitioners -the faculty members who are teaching and organizing Immunology courses. One of the goals of this issue is to give concrete examples of teaching strategies and concepts that could be modified for their own particular situation. In immunologic terms, this could be thought of as affinity maturation: starting with the ideas presented here, approaches can be actively fine-tuned for the particular situation of the faculty preceptor. Another major aspect of diversity illustrated in the articles presented is that students vary immensely in terms of their background knowledge. There are also fundamentally different educational systems in different countries. Finally, the articles reflect inherent constraints of the course such as the time allotted for the class that impact what is possible to cover in Immunology courses. Indeed, perhaps the major challenge in designing courses is not finding important Immunology subjects amid the myriad of interesting topics to cover (1) but rather what to leave out. We have grouped this editorial into sections for the convenience of the reader with particular interests, but it is important to note that the approaches are more general and can be used at different levels of teaching. While these articles highlight the many different ways to approach teaching immunology, they all reflect the enthusiasm and diversity of the faculty who teach immunology.
Student Privacy Issues in Online Learning Environments.

This study explored student privacy issues in online learning environments. Vignettes are used to present the various privacy scenarios occurred in online learning environment. The study showed tha...
Primary aortoenteric fistula: A case report and brief review of the literature

Aortoenteric fistula is a life-threatening emergency and is associated with high morbidity and mortality. Prompt surgical intervention before the aneurysm ruptures lowers the mortality rate to about 50%. Potential imaging mimics for aortoenteric fistula include retroperitoneal fibrosis, mycotic aortic aneurysm, and infectious aortitis. Secondary aortoenteric fistula has relative higher incidence compared to primary and is more common with open aortic repair versus endovascular stent graft repair. Ectopic gas in the aneurysm sac and extravasation of enteric contrast into the aneurysm sac is diagnostic for aortoenteric fistula. However, enteric contrast is not recommended for routine evaluation of aortoenteric because the aforementioned finding is extremely rare. More common imaging findings include bowel loop appearing adherent to aneurysm sac with associated inflammatory stranding and foci or ectopic gas within the aneurysm sac or interposed between the bowel and aneurysm sac. Here we present a case of 52-year-old male who presents with incidental primary aortoenteric fistula.
Branding Co-Creation with Consumer-Generated Advertising: Effect on Creators and Observers

Of the social media tools available to brand managers, consumer-generated advertising (CGA) has attractive features combining consumer-generated content, social media advertising, and online intera...
Dr. Keynes: economic theory in a diagnostic science

THEORY AND PRACTICE For the greater part of his professional life, John Maynard Keynes was known as a practical man: the author of topical tracts on current economic questions, an adviser to, and an emissary from, the British Treasury, a successful player of financial markets for himself and King's College Cambridge, a member of corporate boards and a portfolio manager for two insurance companies. He was, in this sense, a part-time academic. And although he had long been known to be a first-rate economist, it was only after the publication of the General Theory of Employment, Interest and Money in 1936 that he was able to secure his reputation as a first-rate economic theorist. Yet, of the ten volumes of books published in his lifetime, three (the General Theory and the two volumes of the Treatise on Money , volume I subtitled The Pure Theory of Money and volume II The Applied Theory of Money ) feature 'theory' in their title. And if we note that three of the remaining volumes are clearly non-economic and two are as much political as economic, the proportion of his economic books self-consciously styled as theoretical rises to three-fifths. Even one of the remaining volumes, A Tract on Monetary Reform , contains a clearly theoretical core. If Keynes was indeed a theorist, what kind of a theorist was he?
Mechanism of suppression in Drosophila: II. Enzymatic discrimination of wild-type and suppressor tyrosine transfer RNA☆☆☆

Previous studies had shown that two principle forms of tyrosine transfer RNA of Drosophila melanogaster were present in wild-type adult flies but that the second form was virtually absent in a suppressor mutant, su(s)2. Current results are at variance with the previous ones, in that the suppressor mutant has significant amounts of the second form of tRNATyr. A second chromatography system for separating these forms of tRNATyr is described, RPC-5, and is compared to the system used previously, RPC-2. Both systems indicate that wild-type flies contain the two forms of tRNATyr in a ratio of 4060, the suppressor mutant in a ratio of 6040. The difference between current and previous results can be attributed to the procedures used in the preparation of the enzyme that is used as a source of tyrosyl-tRNA ligase. The enzyme activity can be separated into two fractions on DEAE-cellulose chromatography. With suppressor tRNA as substrate, one enzyme fraction charges both forms of tRNATyr but the second enzyme fraction charges the first form preferentially or nearly exclusively in some cases, as was seen in the previous experiments. With wild-type tRNA as substrate both enzyme fractions charge both forms of tRNATyr. Storage results in the loss of the enzyme's ability to discriminate against the second form of tRNATyr from the suppressor mutant, while the enzymatic activity is retained. We postulate that the su(s)+ locus produces an enzyme that modifies the second isoacceptor of tRNATyr and that, when such modification fails to occur (as in the su(s)2 mutant), the tRNA is unable to accept tyrosine from one form of tyrosyl-tRNA ligase. How the discrimination against the second isoacceptor by the ligase may be important metabolically is not apparent.
A Self‐Setting, Monetite (CaHPO4) Cement for Skeletal Repair

A low compressive strength (2 to 4 MPa) but very simple and inexpensive orthopedic CaHPO 4 cement was developed by using commercially available Ca(OH) 2 powders as the only starting powder component. The setting solution used was a special aqueous phosphoric acid (H 3 PO 4 ) solution, with a small amount of sodium hydrogen carbonate (NaHCO 3 ) dissolved in it. Calcium was provided by the powder component, and all of the phosphate came from the setting solution. The setting solution was acidic, and this helped to neutralize Ca(OH) 2 only to the extent of forming the phase of dicalcium phosphate anhydrous (DCPA, monetite), CaHPO 4 . At an L/P (liquid-to-powder) ratio of 1.54 and Ca/P molar ratio of 0.9, the cements had an initial setting time of 19±2 minutes. Set cements comprised only crystalline CaHPO 4 . Monetite has a higher solubility than octacalcium phosphate, β-tricalcium phosphate and calcium hydroxyapatite in aqueous solutions at the physiological pH. This new cement was considered to exhibit a higher in vivo resorbability in comparison to the apatitic cements. Cement samples were characterized by XRD, FTIR and SEM. Compressive strength, initial and final setting times (with the use of Gillmore needles) of the cement samples were also reported.
A Note on MDS Codes, n -Arcs and Complete Designs

A generalized incidence matrix of a design over GF(q) is any matrix obtained from the (0, 1)-incidence matrix by replacing ones with nonzero elements from GF(q). The dimension dq of a design D over GF(q) is defined as the minimum value of the q-rank of a generalized incidence matrix of D. It is proved that the dimension dq of the complete design on n points having as blocks all w-subsets, is greater that or equal to n − w + 1, and the equality dq e n − w + 1 holds if and only if there exists an [n, n − w + 1, w] MDS code over GF(q), or equivalently, an n-arc in PG(w − 2, q).
Development of an Echocardiographic Risk-Stratification Index to Predict Heart Failure in Patients With Stable Coronary Artery Disease: The Heart and Soul Study

Transthoracica 2-dimensional echocardiogram and Doppler flow examination (TTE) generate plethora of high-quality anatomic and physiologic data. However, the abundance and variety of these data can complicate acquisition and analysis, limiting effective integration into clinical settings. To relevantly and efficiently aggregate this information, it is desirable to identify the most potent predictors of dysfunction and adverse outcomes among them. Left ventricular (LV) ejection fraction (EF) is commonly used to predict heart failure (HF) in patients with coronary artery disease (CAD) (1) but is an overtaxed descriptor of systolic function. Numerous TTE-derived measurements can detect subtle changes in myocardial structure and function that offer prognostic information beyond EF. For example, left ventricular mass index (LVMI) predicts mortality independent of other cardiovascular risk factors and electrocardiogram-derived LV hypertrophy (2). Likewise, left atrial enlargement, mitral regurgitation (MR), and diastolic dysfunction (DD) have been shown to predict cardiovascular events, HF, and mortality (3– 6). Other techniques such as Doppler-derived stroke distance (i.e., left ventricular outflow tract velocity–time integral [VTILVOT]) have potential applications in describing global function that might carry unique prognostic relevance (7). The Heart and Soul Study has completed 4.4 years of follow-up on a population of 1,024 subjects with CAD. A comprehensive quantitative echocardiogram and Doppler examination was administered to each participant at enrollment. This study, therefore, provided a suitable vehicle from which to stratify and aggregate TTE data and to determine the most effective combination of noninvasive parameters for the prediction of congestive HF hospital stay. We hypothesized that an array of TTE-derived measurements shown to independently predict congestive HF hospital stay can be combined into a risk-stratification index predictive of HF (the TTE Heart Failure Index). We intend for this index to be readily accessible and to streamline communication among providers.
Acoustic Charge Transport Devices

The sections in this article are 1 Surface Acoustic Wave Devices 2 Display Devices
Maximum likelihood estimation of detector efficiencies in positron emission tomography

In this paper, we introduce a maximum-likelihood (ML) method for estimating detector efficiencies in positron emission tomography. First, we develop a Poisson model for blank scan data obtained from rotating rod sources. Then, we estimate the detector efficiencies using two expectation-maximization (EM) algorithms that differ in the way the maximization step is solved. As desired, the resulting algorithms have the property that the log-likelihood function is non-decreasing as the iteration number increases. Simulation studies using synthetic data demonstrate that the proposed algorithms outperformed two alternative approaches.
Modeling and simulation-the effects of grain coarsening on local stresses and strains in solder microstructure

A critical issue in the long-term reliability of solder connections used in electronic packages is joint failure during thermal cycling. At present, solder is assumed to be a homogeneous single-phase metal in most finite element analyses to predict solder joint fatigue failures. However, in the last decade, several metallurgical studies have shown that solder microstructure may have a role in early solder joint failures. Investigators have observed that solder microstructure coarsens in local bands during aging and during thermal cycle fatigue. In a failed solder joint, the fatigue cracks are found in these bands of coarse grains. It is speculated that the grain coarsening increases local strains within the microstructure, thereby increasing the likelihood for a crack to initiate. The objective of this study is to model and simulate the effect of grain coarsening on local stresses and strains. During solidification of eutectic Pb/Sn solder, two types of microstructures form: lamellar and equiaxed. In this study, the author has developed a computer code to generate both types of microstructures of varying grain coarseness. This code is incorporated into the finite element code that analyzes the local stresses and strains within the computer-generated microstructure. The FE code, specifically developed for this study, uses an algorithm involving the sparse matrix and iterative solver. This code on a typical single-processor machine will allow the analyst to use over 1 million degrees of freedom.
Trojan wavepacket pulses with slow light in media with time and space dependent refraction

Using the formalizm of so-called Wave Function of Photon in strongly refractive time dependent dielectric medium we show that the light trapping in the form of stable nondispersing wavepackets is possible on circular orbits
Magnetic properties of icosahedral R–Mg–Zn quasicrystals (R=Y, Tb, Dy, Ho and Er)

Abstract Large (up to 0.5 cm3) single grains of icosahedral R–Mg–Zn quasicrystals (R=Y, Tb, Dy, Ho and Er) have been grown via a self-flux technique. The samples have a composition of approximately R9Mg34Zn57, and are extremely well-ordered, with little or no evidence of phason strain. These samples have allowed a detailed investigation of the magnetic behaviour of local 4f moments in a quasiperiodic environment. Neutron scattering experiments using powdered single-grains show no evidence for long range magnetic order in the R–Mg–Zn quasicrystals. However, magnetization and magnetic susceptibility measurements indicate a spin-glass state, with freezing temperatures Tf=5.8, 3.6, 2.0 and 1.3 K for R=Tb, Dy, Ho and Er respectively. Deviations from a Curie-Weiss temperature dependence of the susceptibility are small, and only occur for temperatures up to 5 K above Tf, indicating the absence of any significant cluster glass behaviour. In addition, the rare earth dilution series (Y1−xGdx)–Mg–Zn have lower freezing temperatures than (Y1−xTbx)–Mg–Zn, despite the larger de Gennes factor of Gd3+ over Tb3+, indicating that crystal electric fields play a significant role in the freezing phenomenon. This difference between Heisenberg and non-Heisenberg moments is further explored via several (Gd1−xRx)–Mg–Zn pseudo-ternary quasicrystal series.
Effect of the shear parameter on velocity-gradient statistics in homogeneous turbulent shear flow

The effect of the shear parameter on the small-scale velocity statistics in an homogeneous turbulent shear flow is investigated using direct numerical simulations (DNSs) of the incompressible Navier-Stokes equations on a 512 3 grid. We use a novel pseudo-spectral algorithm that allows us to set the initial value of the shear parameter in the range 3-30 without the shortcomings of previous numerical approaches. We find that the tails of the probability distribution function of components of the vorticity vector and rate-of-strain tensor are progressively distorted with increasing shear parameter. Furthermore, we show that the shear parameter has a direct effect on the structure of the vorticity field, which manifests through changes in its alignment with the eigenvectors of the rate-of-strain tensor. We also find that increasing the shear parameter causes the main contribution to enstrophy production to shift from the nonlinear terms to the rapid terms (terms that are proportional to the mean shear) due to the aforementioned changes in the alignment. We attempt to explain these trends using viscous rapid distortion theory; however, while the theory does capture some effects of the shear parameter, it fails to predict the correct dependence on Reynolds number. Comparisons with recent experiments are also shown. The trends predicted by the DNS and the experiments are in good agreement. Moreover, the prefactors in the Reynolds number scaling laws for the skewness and flatness of the longitudinal velocity derivative are shown to have a statistically significant dependence on the shear parameter.
Normal changes in left ventricular filling and hemodynamics during dobutamine stress echocardiography

During high-dose dobutamine infusion, there is a dose-dependent increase in cardiacoutput, a reduction in systemic vascular resistance, a reduction in left ventricular size, an increase in the mitral A wave velocity, a reduction in the E/A velocity ratio, and a reduction in the isovolumic relaxation time, with little change in the rate-corrected isovolumic relaxation time. Left ventricular cavity obliteration is common. This information may be useful in defining the mechanism of hypotension commonly seen during dobutamine stress echocardiography. It is speculated that the diastolic behavior of the left ventricle during dobutamine stress echocardiography, especially the isovolumic relaxation time, may provide an additional indicator of early myocardial ischemia, but this needs to be confirmed by larger independent studies.
The relationship of total Birkeland currents to the merging electric field

Magsat data were used to examine the behavior of Birkeland currents during 1100-2000 UT in consecutive orbits passing near the dawn-dusk meridian. The field was measured with a three-axis fluxgate instrument with a resolution of within 0.5 nT, with the sampling occurring every 1/16th sec. A total of 32 crossings of the Northern Hemisphere auroral zone were available for analysis. The changes in the magnetic readings were correlated more closely with variation in the IMF parameters than to the latitudinal width of the changes. Evidence was found for a relationship between the reconnection electric field and the intensity of the large-scale Birkeland current system. The total conductance of the auroral zone was calculated to be about 18.7 mhos.
Zinc deficiency acts as a co-teratogen with alcohol in fetal alcohol syndrome.

ABSTRACT: Because alcoholism has adverse effects on zinc nutrition and many pregnant women consume less than the recommended dietary allowances of zinc, we postulated that zinc deficiency acts as a co-teratogen with alcohol in the fetal alcohol syndrome. We compared the effects of alcohol on progeny of pregnant mice fed a zinc-deficient diet compared to those fed a diet with adequate zinc. Pregnant CBA mice ((n = 66) were fed the Lieber-DeCarli liquid diet with 0, 15, or 20% ethanol-derived calories containing 0.3 (low) or 8.5 (high) μg zinc/ml. Dams were sacrificed on day 18 of gestation. Resorptions, malformations, and individual fetal weights were recorded. Analysis of fetuses included assays for zinc, assessment of soft tissue malformations, and alizarin red staining for skeletal malformations. Fetal weights were lower in the groups fed the zinc-deficient diet for each concentration of alcohol ((p < 0.005). The groups fed the combination of low zinc plus alcohol had 37-52% resorptions, while the animals on the zinc-deficient diet without alcohol or the high zinc diet with alcohol had 0-2% resorptions. Skeletal malformations were related to alcohol concentration but not zinc intake, while external malformations were higher in those maintained on the low zinc-ethanol diet. These results suggest that zinc deficiency potentiated the teratogenic effects of alcohol and that nutritional intervention for alcoholic women during pregnancy might reduce the incidence or severity of fetal alcohol syndrome.
Self‐Organized Criticality in Riverbank Systems

Abstract Where and when do natural rivers become unstable? To answer this question, we visually estimated bank-failure extent in 100-m increments along 180 km of riverbanks in three watersheds of the northern Yellowstone ecosystem. The riverbank data reveal precise power-law relationships between the number of bank failures of a given size throughout each watershed and the magnitude of those bank failures. The slopes of log-log graphs (i.e., the exponent τ) of bank-failure magnitude versus failure frequency in alluvial reaches vary from 1.07 to 1.44, while τ for all reaches combined (alluvial, colluvial, and bedrock) varies from 1.18 to 1.53, suggesting that lower-gradient, alluvial streams are more susceptible to large bank failures. Cellular automata simulations of riverbanks show similar power-law failure relationships, as do bank-erosion data from a long-term independent dataset from another location. These power-law structures can be interpreted as the spatial signal of a self-organized critical (SOC...