cssi/SciSciGPT-SciSciNet huggingface dataset:
Proper orthogonal decomposition and recurrence map for the identification of spatial–temporal patterns in a low-Re wake downstream of two cylinders

Flow decomposition methods provide systematic ways to extract the flow modes, which can be regarded as the spatial distribution of a coherent structure. They have been successfully used in the study of wake, boundary layer, and mixing. However, real flow structures also possess complex temporal patterns that can hardly be captured using the spatial modes obtained in the decomposition. In order to analyze the temporal variation of coherent structures in a complex flow field, this paper studies the recurrence in phase space to identify the pattern and classify the evolution of the flow modes. The recurrence pattern depends on the time delay and initial condition. In some cases, the flow system will revisit a previous state regardless of the initial state, and in other cases, the system’s recurrence will depend on the initial state. These patterns are determined by the arrangement and interactions of coherent structures in the flow. The temporal order of the repetition pattern reflects the possible ways of flow evolution.
Quantitative and Qualitative Assessments of Cholesterol Association With Bacterial Infection Type in Sepsis and Septic Shock.

Background:Reduced cholesterol levels are associated with increased organ failure and mortality in sepsis. Cholesterol levels may vary by infection type (gram negative vs positive), possibly reflec...
Successful Diagnostic Stewardship for Clostridioides difficile Testing in Pediatrics

Background: As many as 40% of infants aged ≤12 months and 10%–28% of children aged 13–24 months are colonized by Clostridioides difficile. The IDSA and the SHEA recommend that testing should never be routinely recommended for infants ≤12 months of age and should not be routinely performed for children 1–2 years of age unless other causes are excluded. We report implementation of C. difficile diagnostic stewardship at 2 children’s hospitals. Methods: We implemented age-based restrictions for C. difficile testing at hospital A (∼200-bed, free-standing, children’s hospital) and hospital B (∼100-bed children’s hospital within a larger hospital). Both sites are part of the same multicampus institution, and both used nucleic acid amplification testing to detect C. difficile throughout the study. In May 2018, we implemented an electronic order set for C. difficile that provided alerts to avoid testing young infants and patients with recent use of laxatives, stool softeners, or enemas, but providers could order C. difficile testing at their discretion. In October 2018, we implemented a more restrictive diagnostic stewardship algorithm for C. difficile. No testing was allowed for infants aged ≤12 months. Approval pediatric infectious diseases staff was required to test children aged 13–24 months. Pathology resident approval was required to test children aged ≥24 months who had received laxatives, stool softeners, or enemas within ≤24 hours. Clinical microbiology laboratory supervisors reinforced rejection of nondiarrheal stool specimens for testing. Providers at both campuses were informed about the new testing guidelines by e-mail. We compared the number of tests sent and positive cases of healthcare facility-onset C. difficile (HO-CDI) by age strata before and after the implementation of the restrictive testing algorithm. Results: After the intervention, the number of tests in infants significantly declined; 2 infants aged ≤12 months and 4 infants aged 13–24 months were tested for C. difficile (Table). After the intervention, the number of tests per month declined at hospital A, as did the number of HO-CDI cases at both hospitals. Rejections of nondiarrheal stools significantly increased after the intervention (P < .001). Conclusions:C. difficile diagnostic stewardship for children was successfully implemented using a rule-based alert system in the electronic health record. This intervention was associated with a reduced number of tests sent and cases of HO-CDI. This strategy was cost-saving and prevented misdiagnosis, unnecessary antibiotic therapy, and overestimation of HO-CDI rates. Funding: None Disclosures: None
Modular Compact Modeling of MTJ Devices

This paper describes a robust, modular, and physics-based circuit framework to model the conventional and emerging magnetic tunnel junction (MTJ) devices. Magnetization dynamics are described by the stochastic Landau–Lifshitz–Gilbert (sLLG) equation whose results are rigorously benchmarked with a Fokker–Planck equation description of the magnet dynamics. We then show how sLLG is coupled to the transport equations of MTJ-based devices in a unified circuit platform. Step by step, we illustrate how the physics-based MTJ model can be extended to include different spintronics phenomena, including spin-transfer torque, voltage-controlled magnetic anisotropy (VCMA), and spin–orbit torque phenomena by the experimentally benchmarked examples. To demonstrate how our approach can be used in the exploration of novel MTJ-based devices, we present a recently proposed MEMS resonator-driven spin-torque nano-oscillator (STNO) that can reduce the phase noise of STNOs. We briefly elaborate on the use of our framework beyond conventional devices.
The Impact of Burn-In on IC Reliability

In today's highly competitive electronic equipment market, one of the key issues facing equipment manufacturers is whether or not to burn-in integrated circuits. This decision has both reliability and financial implications and may well affect end user satisfaction and repeat business.Unfortunately, there is no simple answer to the question of burn-in. To help develop guidelines for equipment manufacturers to use, 1982-1984 Tl reliability data has been analyzed to provide failure rate improvement factors for burn-in. Using this data, an approach is developed to help the equipment manufacturer make a decision regarding the cost effectiveness of component burn-in.
Chiral Systems Made from DNA

The very chemical structure of DNA that enables biological heredity and evolution has non-trivial implications for the self-organization of DNA molecules into larger assemblies and provides limitless opportunities for building functional nanostructures. This progress report discusses the natural organization of DNA into chiral structures and recent advances in creating synthetic chiral systems using DNA as a building material. How nucleic acid chirality naturally comes into play in a diverse array of situations is considered first, at length scales ranging from an individual nucleotide to entire chromosomes. Thereafter, chiral liquid crystal phases formed by dense DNA mixtures are discussed, including the ongoing efforts to understand their origins. The report then summarizes recent efforts directed toward building chiral structures, and other structures of complex topology, using the principle of DNA self-assembly. Discussed last are existing and proposed functional man-made nanostructures designed to either probe or harness DNA's chirality, from plasmonics and spintronics to biosensing.
On the Quality of Uncertainty Estimates from Neural Network Potential Ensembles

Neural network potentials (NNPs) combine the computational efficiency of classical interatomic potentials with the high accuracy and flexibility of the ab initio methods used to create the training set, but can also result in unphysical predictions when employed outside their training set distribution. Estimating the epistemic uncertainty of an NNP is required in active learning or on-the-fly generation of potentials. Inspired from their use in other machine-learning applications, NNP ensembles have been used for uncertainty prediction in several studies, with the caveat that ensembles do not provide a rigorous Bayesian estimate of the uncertainty. To test whether NNP ensembles provide accurate uncertainty estimates, we train such ensembles in four different case studies, and compare the predicted uncertainty with the errors on out-of-distribution validation sets. Our results indicate that NNP ensembles are often overconfident, underestimating the uncertainty of the model, and require to be calibrated for each system and architecture. We also provide evidence that Bayesian NNPs, obtained by sampling the posterior distribution of the model parameters using Monte-Carlo techniques, can provide better uncertainty estimates.
Spatiotemporal Contrastive Representation Learning for Building Damage Classification

Automatic building damage assessment after natural disasters is important for emergency response. While existing supervised deep learning models achieved good performance on building damage classification, these models require massive human labels for training. Additionally, pre-trained models often fail to generalize well to new disaster events due to gaps between domains associated with training and testing data. In response, this study proposes a novel spatiotemporal contrastive representation learning model for learning features of building damages with big unlabeled data. Experimental results demonstrate superior performance of such features on classifying building damages resulting from various natural disasters (e.g., hurricanes, floods, wildfires, earthquakes, etc.) across different geographic locations worldwide, compared with the state-of-the-art supervised methods.
Skeletal muscle aging, cellular senescence, and senotherapeutics: Current knowledge and future directions.

Abstract Cellular senescence is a state of cell cycle arrest induced by several forms of metabolic stress. Senescent cells accumulate with advancing age and have a distinctive phenotype, characterized by profound chromatin alterations and a robust senescence-associated secretory phenotype (SASP) that exerts negative effects on tissue health, both locally and systemically. In preclinical models, pharmacological agents that eliminate senescent cells (senotherapeutics) restore health and youthful properties in multiple tissues. To date, however, very little is understood about the vulnerability of terminally-differentiated skeletal muscle fibers and the resident mononuclear cells that populate the interstitial microenvironment of skeletal muscle to senescence, and their contribution to the onset and progression of skeletal muscle loss and dysfunction with aging. Scientific advances in these areas have the potential to highlight new therapeutic approaches to optimize late-life muscle health. To this end, this review highlights the current evidence and the key questions that need to be addressed to advance the field’s understanding of cellular senescence as a mediator of skeletal muscle aging and the potential for emerging senescent cell-targeting therapies to counter age-related deficits in muscle mass, strength, and function. This article is part of the Special Issue - Senolytics - Edited by Joao Passos and Diana Jurk.
Proportions of Wood Elements in Stem, Branch, and Root Wood of Black Oak (Quercus Velutina)

The volumetrie proportions of vessel elements, fibres, rays, and axial parenchyma plus vasicentric tracheids were determined for the stern, branch and root wood of threc black oak (Quercus velutina Lam.) trees. There were statistical differences in the proportions of wood elements between locations within the trees sampled, i.e., branches, sterns, roots, oblique roots, and lateral roots. Branches had the highest proportion of vesseI elements, whereas sterns had the greatest proportion ofaxial parenchyma plus vasicentric tracheids. The highest proportions of rays were found in root wood. Fibre proportion was greatest in the stern and branch wood.
Applying SOFL to a Generic Insulin Pump Software Design

Software embedded into medical devices demands a higher standard on its safety, as compared to most commercial software. One of the most important reasons is that the safety issue should be thoroughly investigated. In the United States, Food and Drug Administration FDA is entitled to scrutinize medical devices to ensure they are safe to the public before they enter the market. However, the review of medical device software has been quite challenging because not only the design of medical device software is complicated and error-prone but also the validation of the software system against regulatory requirements is notoriously difficult. Thus, some methodologies based on formal methods have been proposed to alleviate the pain faced by both software developers and regulators such as FDA staff. In this paper, we study how to use the Structured-Object-Based-Formal Language, which is called SOFL to develop a software system controlling an insulin pump, called the Generic Insulin Infusion Pump GIIP. This case study facilitates the understanding of how SOFL can be applied to software systems related to medical devices in terms of the design and review aspects.
Respiration-enhancing Effect of Tuberculin on Splenic Cells of Hypersensitive Guinea Pigs

Oxygen utilization in splenic cells of normal and BCG-sensitized guinea pigs was measured in a Warburg respirometer in the absence and in the presence of Old Tuberculin (OT). In the absence of OT, normal and sensitive cells respired at the same rate; in the presence of OT, normal cell respiration remained unchanged, whereas the respiration of sensitive cells increased significantly. This enhancement of oxygen utilization in sensitive cells was induced with OT but not with Purified Protein Derivative and it was most pronounced during the first hour of the interaction between the cells and the antigen. When normal splenic cells were treated with an extract of hypersensitive cells, their respiration was enhanced in the presence of OT. Oxygen utilization in cells of desensitized animals did not differ from that in cells of normal animals. The absence of reactivity to OT in splenic cells and in the skin of desensitized guinea pigs suggested that both phenomena are expressions of antigen-induced biological changes in cells of animals with delayed hypersensitivity.
Toward a Real-Time Service for Landslide Detection: Augmented Explicit Semantic Analysis and Clustering Composition Approaches

The use of Social Media for event detection, such as detection of natural disasters, has gained a booming interest from research community as Social Media has become an immensely important source of real-time information. However, it poses a number of challenges with respect to high volume, noisy information and lack of geo-tagged data. Extraction of high quality information (e.g., Accurate locations of events) while maintaining good performance (e.g., Low latency) are the major problems. In this paper, we propose two approaches for tackling these issues: an augmented Explicit Semantic Analysis approach for rapid classification and a composition of clustering algorithms for location estimation. Our experiments demonstrate over 98% in precision, recall and F-measure when classifying Social Media data while producing a 20% improvement in location estimation due to clustering composition approach. We implement these approaches as part of the landslide detection service LITMUS, which is live and openly accessible for continued evaluation and use.
Parental rights and decision making regarding vaccinations: ethical dilemmas for the primary care provider.

Purpose: To discuss the ethical dilemma that a primary care nurse practitioner (NP) must face when parents refuse to have their children immunized. Data sources: Review of published literature on the topic. Conclusions: By listening carefully to their concerns, responding honestly, and providing clear information about the risks and benefits, NPs may be able to build trust and to convince once hesitant parents to have their children immunized. For those parents who refuse, NPs may feel uncertain on how to respond. By considering the ethical principles to which they are bound, autonomy, beneficence, and non-maleficence, NPs can work with the parents to decide what treatment is best for the child. Implications for practice: Providing truthful information to parents and utilizing public awareness through recent discussions in the media and on the Internet may be able to obviate many of the concerns of parents, which may be getting in the way of universal immunization.
Spectral Properties of Reaction Center Preparations from Rhodopseudomonas spheroides

Abstract The absorption, circular dichroism, and fluorescence spectra have been measured on oxidized and reduced reaction center preparations from Rhodopseudomonas spheroides strain R-26 at 295 and 77° K. The spectra indicate that the 4 bacteriochlorophyll a and 2 bacteriopheophytin a molecules in the reaction center are contained in a single pigment complex. The absorption bands at 893, 804, and 760 in the red and near-infrared each resolve into two separate CD maxima at 77°K. The interaction is very strong between the pigment molecules and their orientations are not coplanar. Oxidation of the reaction center bleaches the 893-nm absorption band of a bacteriochlorophyll dimer and the two corresponding CD maxima disappear. The changes in the low temperature fluorescence and CD spectra suggest that the molecular orientation may change when the reaction center is oxidized.
Calixarenes 9 : Conformational isomers of the ethers and esters of calix[4]arenes

Abstract Calix[4]arene (1A), p-t-butylcalix[4]arene (1B), and p-allylcalix[4]arene (1C) have been converted to various derivatives, including the methyl, ethyl, allyl, benzyl and trimethylsilyl ethers and the acetates. Although the parent calixarenes exist preferentially in the cone conformation, they are conformationally flexible and at room temperature interconvert at a rate of ca 100 sec−1. All but the methyl ethers, on the other hand, are conformationally rigid at room temperature. The preferred conformations in most cases are the cone and partial cone, depending on the derivative formed (i.e. methyl and ethyl ethers favor the partial cone; benzyl and trimethylsilyl ethers favor the cone). In the cases of the allyl ethers and the acetates the p-substituents appear to influence the conformational outcome (i.e. 1A and 1B form the allyl ethers in the partial cone and cone conformation, respectively; 1A and 1B form the acetates in the 1,3-alternate and partial cone conformation, respectively). The conformationally rigid calixarene derivatives in the cone and partial cone conformations belong to the small group of synthetic compounds that contain a permanent cavity (a “changeless calix”) whose dimensions are large enough to encapsulate other molecules.
Requirement for negative charge on “activation loop” of protein kinase C.

Increasing evidence has implicated a post-translational phosphorylation in the production of a catalytically competent protein kinase C. Here we present structural and biochemical evidence that Thr500 of protein kinase C-beta II is the residue phosphorylated by another kinase. Modeling studies indicate that this residue is part of a "lip" structure at the entrance of the catalytic site; phosphorylation on this lip, or "activation loop," is central to the regulation of three kinases whose structures have been elucidated (Taylor, S. S., and Radzio-Andzelm, E. (1994) Structure 2, 345-355). Biochemical data reveal that mutation of Thr500 to an acidic residue (Glu) results in expression of catalytically active protein kinase C in COS cells. In contrast, mutation of this residue to a neutral, non-phosphorylatable residue (Val) results in expression of inactive enzyme. Thus, negative charge at position 500 is required for catalytically competent protein kinase C-beta II. These data suggest that signal processing by protein kinase C cannot occur until the enzyme is first phosphorylated by a protein kinase C kinase.
Regulation of the hypothalamic-pituitary-adrenal axis in free-living pigeons

We studied feral free-living pigeons (Columba livia) to determine whether either unstressed or stress-induced corticosterone release was altered during a prebasic molt. The pigeons were at various stages of molt throughout the study, but corticosterone responses in molting and nonmolting birds did not differ. This was further reflected in equivalent adrenal responses to exogenous adrenocorticotropic hormone (ACTH), suggesting equivalent steroidogenic capacity of adrenal tissues during both physiological states. There was a slight change, however, in pituitary regulation during molt. Whereas exogenous arginine vasotocin (AVT) elevated corticosterone levels in nonmolting birds, during molt an equivalent dose of AVT was ineffective, suggesting that the pituitary is less sensitive to an AVT signal during molt. AVT also appears to be more effective than corticotropin-releasing factor at eliciting ACTH release in pigeons. Overall, these data indicate that pigeons regulate their corticosterone release differently during molt than other avian species studied to date.
Effects of Neutron Irradiation on the Microstructure and Microhardness of Niobium-Base Alloys

The microstructure and microhardness of several niobium-base binary and ternary alloys were investigated following fast neutron irradiation to a fluence of 18 dpa (4.8 x 10 2 2 n/cm 2 , >0.1 MeV) at 650°C. Transmission electron microscope (TEM) procedures were employed to observe the microstructure of the alloy specimens following neutron irradiation and in the unirradiated condition. Microhardness measurements were made on irradiated and unirradiated specimens to obtain information on the effects of irradiation on mechanical properties. Neutron irradiation of the Nb-1Mo and Nb-5Mo-1Zr alloys produced voids and a high density of dislocation loops. No voids were observed in the irradiated Nb-lZr alloy. Microhardness measurements of the irradiated alloys indicated that the effect of the fast neutron irradiation was to increase the microhardness of all the niobium-base alloys. The magnitude of the microhardness increase was found to be a function of the alloy composition, with the smallest increase observed in the Nb-5Mo-1Zr alloy. The observations in this study are in agreement with the previous work, which has shown that molybdenum and zirconium additions were effective in suppressing void formation in niobium-base alloys for irradiation temperatures up to ∼1100°C.
Heart rate and ischemic stroke: the REasons for Geographic And Racial Differences in Stroke (REGARDS) study.

BackgroundThe association between resting heart rate and ischemic stroke remains unclear.AimTo examine the association between resting heart rate and ischemic stroke.MethodsA total of 24 730 partic...
Coenzyme Q10 dose-escalation study in hemodialysis patients: safety, tolerability, and effect on oxidative stress

Background Coenzyme Q10 (CoQ10) supplementation improves mitochondrial coupling of respiration to oxidative phosphorylation, decreases superoxide production in endothelial cells, and may improve functional cardiac capacity in patients with congestive heart failure. There are no studies evaluating the safety, tolerability and efficacy of varying doses of CoQ10 in chronic hemodialysis patients, a population subject to increased oxidative stress.
Prescription Patterns of Psychotropic Medications in Elderly Compared With Younger Participants Who Achieved a “Recovered” Status in the Systematic Treatment Enhancement Program for Bipolar Disorder

Objectives This study compares prescription patterns between young adults and elderly with bipolar disorder who achieved a recovery status during the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD). Design STEP-BD is a multicenter National Institute of Mental Health-funded project designed to evaluate the longitudinal outcome of patients with bipolar disorder. The STEP-BD study involved extensive assessment across multiple domains including demographic data, diagnosis, symptom severity, treatment, and clinical status. Patients achieved “recovered” status when they experienced eight consecutive weeks without significant symptoms. Participants The authors analyzed data of all subjects who achieved a recovered status at least once in their participation. Measurements The authors compared treatment regimes and doses among young participants with middle age (N = 3,364), 20–59 years old, and older participants 60 and above (N = 246). Results Of the 3,615 STEP-BD participants who had a lifetime diagnosis of bipolar subtypes I or II, 67.6% (N = 2442) achieved a recovered status during their participation. A total of 78.5% (N = 193) of older patients recovered compared with 66.8% of the younger cohort. On average, participants who reached a recovered status took 2.05 medications with no difference between age groups. Lithium was prescribed to 37.8% of younger patients compared with only 29.5% of older participants. The mean dosages taken by younger and older patients differed significantly only for lithium, valproate, and risperidone with elderly individuals prescribed lower daily dosages. Significant reduction in lithium dosing was observed among individuals aged 50 and older and among individuals 60 and older for valproate. Although valproate was more often prescribed, 42.1% of recovered bipolar elder achieved recovery with lithium alone compared with only 21.3% of the younger cohort. Conclusion This data shows recovery is achievable in the elderly though more than one medication is often needed regardless of age.
Direct Participation of Starburst Amacrine Cells in Spontaneous Rhythmic Activities in the Developing Mammalian Retina

Spontaneous, rhythmic waves of excitation in the developing mammalian retina play a critical role in the formation of precise neuronal connectivity in the visual system. However, it is not known what circuits in the retina are responsible for the production of these waves. Using patch-clamp recordings in the whole-mount neonatal rabbit retina, this study reports that the displaced starburst amacrine cell, a unique cholinergic interneuron in the ganglion cell layer of the retina, undergoes rhythmic bursts of membrane depolarization with a frequency and duration similar to those of spontaneous retinal waves. Simultaneous patch-clamp recordings from pairs of neighboring starburst and ganglion cells show that the rhythmic activity in starburst cells is closely correlated with that in ganglion cells, and that the excitation in both cell types is most likely driven by synaptic input. However, in contrast to ganglion cells, displaced starburst cells usually do not generate spontaneous somatic action potentials. Instead, they seem to use subthreshold potentials (at least at the soma) to mediate the rhythmic excitation. The results suggest that acetylcholine is likely released rhythmically in the developing retina. Thus, starburst amacrine cells form the first identified network of retinal interneurons that directly participate in spontaneous rhythmic activities in the developing retina.
Effects of radiation damage on the charge density wave transitions in NbSe3

Abstract We have measured the electrical resistivity of NbSe 3 samples which have been radiation damaged with 2.5 MeV protons up to a defect concentration of 0.5%. We find that, unlike substitutional impurities, the defects do not destroy the charge density wave (CDW) transitions and the samples do not go superconducting. The defects become more effective scatterers below the CDW transitions so that the defect resistivity is temperature dependent. The defects pin the CDWs randomly so that carriers in the unnested regions can be scattered by the CDW. This leads to an enhancement of the defect resistivity. The resistivity of the highly damaged samples is still increasing with decreasing temperatures to below 1 K.
Spontaneous Chromatin Rearrangements in Drosophila

SPONTANEOUS chromosomal rearrangements are considered to be rare in Drosophila. (Pale and blond are the known cases.) During the past few years I have found two new cases of considerable interest, the detailed analysis of which was delayed by external circumstances. Both cases occurred in pedigree and closely watched cultures, the abnormal broods being among numerous identical normal ones.
Pursuit of thinness and onset of eating disorder symptoms in a community sample of adolescent girls: A three‐year prospective analysis

Community-based prospective studies are needed to shed light on mechanisms that may influence development of eating disorders and identify variables that could serve as potential targets for prevention efforts. In this paper we examine level of weight preoccupation and other variables prospectively associated with age of onset of eating disorder symptoms over a 3-year interval in a community sample (N = 939) of young adolescent girls. 3.6% (32/887) experienced onset of symptoms over the interval. Only one factor, a measure of Weight Concerns, was significantly associated with onset (p < .001). Girls scoring in the highest quartile on the measure of Weight Concerns had the shortest survival time (12% incidence by age 14.5) and those scoring in the lowest quartile had the highest survival time (2% incidence by age 14.5; p < .001). This finding is consistent with both theoretical and clinical perspectives and represents one of the first prospective demonstrations of a linkage between weight and body shape concerns and later onset of eating disorder symptoms. An understanding of the independent variables that predispose girls to development of symptoms is a useful step towards the establishment of a rational basis for the choice of a prevention intervention target.
Localised giant pseudopolyposis secondary to ulcerative or granulomatous colitis.

Pseudopolyps which represent polypoid oedematous tags, regenerating mucosal islands between ulcerations or heaped-up granulation tissue covered by epithelium, are a common sequela of ulcerative colitis and may also occur secondary to granulomatous colitis. Occasionally, a large discrete mass of pseudopolyps occurs simulating a villous-like or polypoid neoplasm and the term ‘localised giant pseudopolyposis’ has been applied to this phenomenon. In this paper the radiological appearances of localised giant pseudopolyposis secondary to ulcerative or granulomatous colitis are described and illustrated. The differential diagnosis is discussed and four new cases are added to eight previously reported in the literature.
Down-modulation of the costimulatory molecule, CD28, is a conserved activity of multiple SIV Nefs and is dependent on histidine 196 of Nef.

In this study Nef proteins derived from simian immunodeficiency virus (SIV) and human immunodeficiency virus (HIV) were compared to assess their abilities to down-modulate the cell surface levels of the T-cell costimulatory molecule CD28. We demonstrate that in addition to Nef derived from the prototypic SIVmac239, Nef proteins encoded by the pathogenic SIVsmmPBj molecular clone and the SIVsmmB670 isolate also down-modulate cell surface CD28. In contrast, Nef proteins derived from HIV failed to down-modulate CD28. We have also identified H196 as a critical residue which influences the capacity of SIVmac Nef to down-modulate CD28. Nef derived from SIVmacJ5 failed to down-modulate cell surface CD28, whereas a Q196H substitution mutant of SIVmacJ5 Nef was able to down-modulate cell surface CD28. Conversely, substitution of H196 to Q196 in SIVmac239 Nef resulted in a mutant that had minimal effect on cell surface CD28 expression, despite retaining the capacity to down-modulate cell surface CD3epsilon. H196 lies immediately adjacent to a documented di-leucine endocytic motif and mutation of this motif also abrogated the ability of SIVmac239 Nef to down-modulate CD28. These findings demonstrate that down-modulation of the costimulatory molecule, CD28, and clonotypic TCR/CD3 complex are conserved attributes of SIV Nef.
The leishmania-leptomonad transformation of Leishmania donovani: nutritional requirements, respiration changes and antigenic changes.

SYNOPSIS. The leishmania-leptomonad transformation of Leishmania donovani occurs in 20–40 hr in vitro at 27 C in the absence of cell division. The rate and extent of the process depend on the available nutrients. A source of amino adds and glucose (or sucrose) are required. Several basic or acidic amino acids can substitute for all amino acids present in the complete medium. Leishmanial forms freshly isolated from hamster spleen have a QO2 (μM O2/min/107 cells) of 0.29 ± 0.01 at 27 C in phosphate buffered saline with glucose. This respiration is sensitive to KCN, antimycin A, and Na amytal, and hence is probably cytochrome dependent. The QO2 remains constant for 5–6 hr and then increases 5–7 fold by 20–30 hr of incubation at 27 C in the proper medium. The transformation is inhibited in terms of morphogenesis and increase in respiration by Actinomycin D, puromycin and mitomycin C. Appearance of new soluble antigens during the transformation was found by gel diffusion and immunoelectrophoresis.
The identification of telomerase subunits: catalysing telomere research

Telomerase is the ribonucleoprotein complex responsible for the addition of simple sequences onto the physical ends, or telomeres, of most eukaryotic chromosomes. The activity of this complex is essential for the maintenance of genome integrity. Recent studies have begun to dissect the mechanism of telomerase action through the identification of a reverse-transcriptase-like activity as a catalytic subunit. At the same time, the regulation of telomere length appears to be a complex and possibly species-specific process, involving factors that are likely to interact with both the telomere and telomerase.
Characterization and Activity of Ferric-Sulfide-Based Catalyst in Model Reactions of Direct Coal Liquefaction: Effect of Preparation Conditions

We have studied the activity of various ferric-sulfide-based catalysts in model hydrogenation and cracking reactions under conditions typical of direct coal liquefaction (DCL). The catalysts used were mixtures of FeS2 (pyrite, PY) and nonstoichiometric FeSx (pyrrhotite, PH) obtained by high-temperature disproportionation of ferric sulfide in a nitrogen atmosphere or a hydrogen atmosphere. The structural changes in the catalyst were also examined, both before and after the model reactions. The cracking functionality of the catalysts was studied by using cumene, and the hydrocracking functionality was studied by using diphenylmethane. Phenanthrene was used as a model compound for hydrogenation and hydrogen shuttling. Phenanthrene hydrogenation was studied in the presence of H2(g), and hydrogen shuttling was studied when a hydrogen donor (tetralin) was present in the absence of H2(g). All the model reactions were performed under conditions typical of DCL: 400 °C and 1000 psig for 30 min. The surface and bul...
Determining Sample Size and a Passing Criterion for Respirator Fit-Test Panels

Few studies have proposed methods for sample size determination and specification of passing criterion (e.g., number needed to pass from a given size panel) for respirator fit-tests. One approach is to account for between- and within- subject variability, and thus take full advantage of the multiple donning measurements within subject, using a random effects model. The corresponding sample size calculation, however, may be difficult to implement in practice, as it depends on the model-specific and test panel-specific variance estimates, and thus does not yield a single sample size or specific cutoff for number needed to pass. A simple binomial approach is therefore proposed to simultaneously determine both the required sample size and the optimal cutoff for the number of subjects needed to achieve a passing result. The method essentially conducts a global search of the type I and type II errors under different null and alternative hypotheses, across the range of possible sample sizes, to find the lowest s...
The differential effects of repeating kindergarten

We use the Early Childhood Longitudinal Study to investigate national patterns addressing (a) who repeats kindergarten, and (b) the subsequent cognitive effects of this event. Using OLS regression techniques, we investigate 1st-time kindergartners who are promoted, 1st-time kindergartners who are retained, and children who are already repeating kindergarten. Boys, children from low socioeconomic backgrounds, and children who enter kindergarten younger than typical age standards are consistently at risk for repeating kindergarten, but racial/ethnic patterns differ across the 2 cohorts of kindergarten repeaters. Evidence suggests that repeating kindergarten rarely leads to cognitive benefits in literacy or mathematics performance. On average, kindergarten repeaters continue to perform below their peers in terms of literacy skills both at the end of kindergarten and at the end of first grade (effect size [ES] = −0.20 and −0.24, respectively). In mathematics, the performance differentials are smaller but rema...
Analytical Model to Predict Thermomechanical Relaxation of Shot Peening Induced Residual Stresses

Shot peening is widely used to improve the fatigue life of engine blades and rotors by inducing compressive residual stress on component surfaces. However, the residual stresses can relax due to exposure at high service temperature and mechanical loading. A physics-motivated analytical solution is developed to predict the residual stress relaxation at high temperature and under mechanical loading. In this thermomechanical relaxation model, the plastic strains in the shot peening layer and the substrate are obtained analytically by using linear kinematic hardening material law, and the plastic strain evolution at high temperature is modeled by using a recovery strain term. The final residual stress as a function of time, temperature, and mechanical loading is obtained analytically by combining this recovery strain with equilibrium and compatibility conditions. The whole method can be implemented into Microsoft Excel, and is easy to use and validate. As a special case, an analytical closed-form solution to predict the pure thermal relaxation of a shot peening residual stress is developed. The model predictions agree satisfactorily with published experimental measurements.
For the love of Jodie Foster: star demystification and national configuration

This essay examines Jodie Foster's public response to John W. Hinckley Jr's attempt to assassinate President Ronald Reagan as a moment when the discourses of stardom and nationalism collided with noteworthy friction. It argues that when Foster responded to Hinckley's attempted hit by signifying and referring to her own star production, she challenged the veneer of heterosexuality that had been cast around her and exposed the hitherto unseen connections between heteronormative love and the president, the ultimate embodiment of the nation-father. This, in turn, it shall also be argued, destabilized the national sexual imaginary that Reagan and Hinckley had established between the American public and the Hollywood film industry.
A Theory of Interindustry Wage Structure Variation

I. Introduction, 282. — II. Productivity and the Wage Structure, 282. — III. Unionism and Earnings, 285. — IV. Variation in the Wage Structure, 290. — V. The Statistical Evidence, 1923–1940, 295. — VI. Conclusion, 305.
Effect of phospholipid acyl chain modulation on vitamin E incorporation into pulmonary artery endothelial cell membranes

Incorporation of vitamin E (α-tocopherol) was measured in total membranes of pulmonary artery endothelial cells (PAEC) following treatment with eight synthetic phosphatidylethanolamines (PE) (Palmitoyloleoyl, 16:0–18:1 PE1; distearoyl, 18:0–18:0 PE2; dioleoyl, 18:1–18:1 PE3; stearoyl- linoleoyl, 18:0–18:2 PE4; dilinoleoyl, 18:2–18:2 PE5; stearoyl-arachiod-nyl, 18:0–20:4 PE6; diarachidonyl, 20:4–20:4 PE7; and stearoyl-docosahexenoyl, 18:0–22:6 PE8). Endogenous PE content of native membranes was 0.88 ± 0.01 nmol/mg protein. Incorporation of PE irrespective of fatty acid content significantly (P < 0.02) increased the PE content of total membranes. Vitamin E incorporation in control membranes was 63 ± 9 nmol/mg protein. Incorporations of vitamin E in PE1- to PE7-treated cells were significantly (P < 0.05) increased compared to controls and were comparable to each other. Vitamin E incorporation into PE8-treated cells was threefold greater (P < 0.001) thatn controls and twofold greater (P < 0.001) than PE1- to PE7-treated cells. Increased PE content results in increased vitamin E incorporation into PAEC membranes irrespective of the fatty acids present on the acyl chain, and maximal incorporation of vitamin E in PE8-treated cells may relate to the increased carbon chain length rather than to the degree of unsaturation at the sn2 position. © 1993 Wiley-Liss, Inc.
Everyday verbal memory and pediatric epilepsy

This study addressed the reliability and validity of reports of everyday verbal memory with a sample of 132 pediatric patients with epilepsy. Each patient and one parent completed a questionnaire on everyday verbal memory comprising two scales assessing learning/retrieval and prospective memory. Each patient was also administered tests of memory, attention, and academic skills. Information about attention, mood, and academic performance was obtained from parent and teacher report, as well as self-report. Memory test scores were correlated with children's reports of learning and retrieval in everyday activities, but were not significantly associated with reports of prospective memory. Reports of everyday memory were found to be reliable and predictive of academic performance. Performance on tests of memory, conversely, was unrelated to reports of academic performance. Reports of everyday memory may, therefore, provide more useful information than tests when evaluating the effects of epilepsy and its treatments.
Liposome-mediated transfer of nitric oxide synthase gene improves renal function in ureteral obstruction in rats1

Liposome-mediated transfer of nitric oxide synthase gene improves renal function in ureteral obstruction in rats Background The protective effect of nitric oxide has been demonstrated in several renal disease models. We augmented renal nitric oxide production by transfer of the inducible nitric oxide synthase (iNOS) gene into rat kidney in controls and in unilateral ureteral obstruction (UUO). Methods The human iNOS gene was inserted into a pcDNA 3.1-backbone plasmid with the FLAG epitope (FLAG-iNOS). In vitro, transduction of FLAG-iNOS was confirmed by Western blot and Griess reaction. In vivo, we transfected either FLAG-iNOS or control plasmid (CMV-LacZ), using cationic liposomes. Urinary nitric oxide metabolites and immunohistochemistry confirmed iNOS transduction. Renal function was also assessed. Results In vitro, increased iNOS expression was demonstrated in human embryonic kidney (HEK293) cells, along with increased release of nitric oxide metabolites, NO2/NO3. In vivo, FLAG-iNOS was detected by polymerase chain reaction (PCR) up to 35 days after the transfection. Urine collection documented increased urinary NO2/NO3. Immunohistochemistry localized iNOS to collecting ducts, distal tubules, and glomerulus of the injected kidney. Renal function measured up to 21 days after transfection in control animals was not significantly different between the two groups. In contrast, renal function after 24 hours of UUO was significantly improved in FLAG-iNOS–treated animals. Conclusion This study demonstrates the feasibility of liposome-mediated iNOS gene transfer into the kidney. Furthermore, the improvement of renal function in UUO demonstrates that the transfected iNOS gene is active and suggests that decreased iNOS activity contributes to the decreased renal function in UUO. This iNOS construct may have therapeutic utility in the pathophysiologic sequelae of UUO and other renal diseases.
What Price Survivability? Progress vs. Perfection

Expectations for the survivability of U.S. strategic forces and command, control, and communications (C3) may exceed the requirements of political prudence and military necessity. U.S. forces and commanders need not be expected to survive improbable threats and extreme worst-case scenarios. Given technical limitations and political probabilities, the requirements for survivability should include allowing for evolutionary adjustment of capabilities and technologies. Imposing irrelevant survivability requirements may also be self-defeating for American strategy, as the case of MX illustrates.
Osteoprotective Benefits of Exercise: More Pain, Less Gain?

Based on the results of their study, Hagberg et al. suggested that physical activity that is moderate in intensity might be most appropriate for the prevention of osteoporosis in postmenopausal women. The take-home message is that being physically active has osteoprotective benefits. However, the implication that more vigorous exercise is less beneficial must be carefully scrutinized. When compared with the physically active nonathletes, the highly trained athletes in this study tended to be more years beyond menopause, had been on HRT for a smaller proportion of the postmenopausal period, and may have had lower endogenous estrogen levels as a result of having less fat mass. The chronic exposure of the skeleton to estrogens very likely played a more prominent role in determining BMD status in the women in this study than the investigators were able to ascertain, owing largely to the cross-sectional nature of the investigation. It is safe to conclude that an exercise prescription for the prevention of osteoporosis should include weight-bearing exercise, but the optimal intensity, frequency, and duration of exercise remain to be established. The results of the study by Hagberg et al. emphasize the importance of physical activity for sustaining BMD, but should not provide a basis for discouraging women from performing vigorous exercise.
Optimization issues in physiological toxicokinetic modeling: a case study with benzene

This paper compares two methods for global optimization of physiologically based toxicokinetic models: Monte Carlo optimization, which searches randomly for the optimum; and the simplex method, which updates systematically an array of parameter values. Two measures of goodness-of-fit are also contrasted: criterion function and likelihood. A 14-parameter model of benzene distribution in rats is used to illustrate these techniques. Simplex optimization yields better fits overall. However, the measurement of uncertainty offered by Monte Carlo simulations is a major argument in favor of their use.
Ceftibuten:† Development of a Commercial Process Based on Cephalosporin C. Part IV. Pilot-Plant Scale Electrochemical Reduction of 3-Acetoxymethyl-7(R)-glutaroylaminoceph-3-em-4-carboxylic Acid 1(S)-Oxide

This contribution describes the operation of a pilot plant for the production of 3-exomethylene-7(R)-glutaroylaminocepham-4-carboxylic acid 1(S)-oxide (4a) by the electrochemical reduction of 3-acetoxymethyl-7(R)-glutaroylaminoceph-3-em-4-carboxylic acid 1(S)-oxide (3a). This conversion is a key step in a new process for the production of Ceftibuten (1). The scale-up of the electrochemical reduction was demonstrated using a commercial flow-cell. The use of a novel type of extended-area tin cathode, which had been shown on a laboratory scale to produce significant improvements in the process, was successfully implemented in an ICI FM21-SP commercial-scale electrochemical reactor.
Prevention of rapid immune elimination of anti-lymphocytic globulin in transplant patients.

Prior treatment of human allograft recipients with aggregate-free normal horse immunoglobulin circumvents the problem of antibody formation in subsequent anti-lymphocytic globulin therapy.
Immune-Mediated Encephalopathies with an Emphasis on Paraneoplastic Encephalopathies

Recent identification of syndromes encompassing psychiatric symptoms, seizures, and movement disorders has led to effective treatments for several previously obscure conditions now known to be immune-mediated encephalopathies. In contrast to long-recognized paraneoplastic neurologic syndromes associated with antibodies to intracellular antigens, these more recently described disorders are not always paraneoplastic, are associated with cell surface antibodies, and may respond to immunosuppressive therapies. In this review, the author discusses clinical presentations, differential diagnosis, immunologic evaluation, and therapeutic options for both groups of disorders.