cssi/SciSciGPT-SciSciNet huggingface dataset:
Medicaid trends in prescription opioid and non-opioid use by HIV status.

Abstract Background Pain is more common among people living with HIV (PLWH) than their counterparts; however, it is unclear whether analgesic use differs by HIV status. Methods We analyzed Medicaid pharmacy claims from adults in 14 US states from 2001 to 2009 to identify opioid and non-opioid analgesic prescriptions and compared prescribing trends by HIV status. We accounted for clinical and demographic differences by using inverse probability weights and by restricting the sample to a subgroup with a common comorbidity, diabetes, chosen for its high prevalence and association with lifestyle and chronic pain. We estimated the incidence of chronic opioid therapy (COT) (≥90 consecutive days with an opioid prescription) among opioid-naive individuals. Results Rates of opioid and non-opioid use increased approximately two-fold from 2001 to 2009. PLWH received approximately twice as many prescriptions as those without HIV. In an unadjusted Cox regression, PLWH were three times more likely to receive COT compared to those without HIV (hazard ratio (HR) = 3.06, 95% CI 2.76–3.39). When restricting to patients with diabetes and adjusting for age, sex, state, comorbidity score, depression, bipolar disorder, and schizophrenia, the HR decreased to 1.26 (95% CI 0.97–1.63). Conclusions Higher opioid use among PLWH was largely a function of patients’ demographic characteristics and health status. The high incidence of COT among PLWH underscores the importance of practice guidelines that minimize adverse events associated with opioid use.
Data clustering using proximity matrices with missing values

Abstract In most applications of data clustering the input data includes vectors describing the location of each data point, from which distances between data points can be calculated and a proximity matrix constructed. In some applications, however, the only available input is the proximity matrix, that is, the distances between each pair of data point. Several clustering algorithms can still be applied, but if the proximity matrix has missing values no standard method is directly applicable. Imputation can be done to replace missing values, but most imputation methods do not apply when only the proximity matrix is available. As a partial solution to fill this gap, we propose the Proximity Matrix Completion (PMC) algorithm. This algorithm assumes that data is missing due to one of two reasons: complete dissimilarity or incomplete observations; and imputes values accordingly. To determine which case applies the data is modeled as a graph and a set of maximum cliques in the graph is found. Overlap between cliques then determines the case and hence the method of imputation for each missing data point. This approach is motivated by an application in plant breeding, where what is needed is to cluster new experimental seed varieties into sets of varieties that interact similarly to the environment, and this application is presented as a case study in the paper. The applicability, limitations and performance of the new algorithm versus other methods of imputation are further studied by applying it to datasets derived from three well-known test datasets.
A Mechanistic Model for the Extraction of Phenolics from Grapes During Red Wine Fermentation.

Phenolic extraction is a critical part of red wine making. Though empirical models of phenolic extraction kinetics exist, the current level of mechanistic understanding does not allow for accurate predictions. In this work, we propose a mechanistic model for the extraction of phenolics from grape skins and seeds as a function of temperature and ethanol. This model examines the release of phenolics, the adsorption of phenolics onto grape material, and the disappearance of anthocyanins from solution. Additionally, we performed epifluorescence microscopy to explore our finding that seed tannins’ release rate appears independent of concentration, and found that the grape seed appears to ablate over fermentation. We also determined the activation energy of anthocyanin disappearance, in good agreement with similar systems. The proposed model results in an excellent fit, and increases the understanding of phenolic extraction and the ability to predict and optimize product outcome in red wine making.
Evaluating the capacity of connectome analysis to predict survival in high-grade astrocytoma.

2049Background: While factors such as age, histology and tumor molecular variants (e.g. IDH status) contribute to prognosis in patients with high grade astrocytoma (HGA), there remains a wide varia...
High-resolution cryo-electron microscopy structure of the Escherichia coli 50S subunit and validation of nucleotide modifications

ABSTRACT Post-transcriptional ribosomal RNA (rRNA) modifications are present in all organisms, but their exact functional roles and positions are yet to be fully characterized. Modified nucleotides have been implicated in the stabilization of RNA structure and regulation of ribosome biogenesis and protein synthesis. In some instances, rRNA modifications can confer antibiotic resistance. High-resolution ribosome structures are thus necessary for precise determination of modified nucleotides’ positions, a task that has previously been accomplished by X-ray crystallography. Here we present a cryo-electron microscopy (cryo-EM) structure of Escherichia coli (E. coli) 50S subunit at an average resolution of 2.2A as an additional approach for mapping modification sites. Our structure confirms known modifications present in 23S rRNA and additionally allows for localization of Mg2+ ions and their coordinated water molecules. Using our cryo-EM structure as a testbed, we developed a program for identification of post-transcriptional rRNA modifications using a cryo-EM map. This program can be easily used on any RNA-containing cryo-EM structure, and an associated Coot plugin allows for visualization of validated modifications, making it highly accessible.
Finding fields and self-force in a gauge appropriate to separable wave equations

Gravitational waves from the inspiral of a stellar-size black hole to a supermassive black hole can be accurately approximated by a point particle moving in a Kerr background. This paper presents progress on finding the electromagnetic and gravitational field of a point particle in a black-hole spacetime and on computing the self-force in a ``radiation gauge.'' The gauge is chosen to allow one to compute the perturbed metric from a gauge-invariant component ${\ensuremath{\psi}}_{0}$ (or ${\ensuremath{\psi}}_{4}$) of the Weyl tensor and follows earlier work by Chrzanowski, Cohen, and Kegeles (we correct a minor, but propagating, error in the Cohen-Kegeles formalism). The electromagnetic field tensor and vector potential of a static point charge and the perturbed gravitational field of a static point mass in a Schwarzschild geometry are found, surprisingly, to have closed-form expressions. The gravitational field of a static point charge in the Schwarzschild background must have a strut, but ${\ensuremath{\psi}}_{0}$ and ${\ensuremath{\psi}}_{4}$ are smooth except at the particle, and one can find local radiation gauges for which the corresponding spin $\ifmmode\pm\else\textpm\fi{}2$ parts of the perturbed metric are smooth. Finally a method for finding the renormalized self-force from the Teukolsky equation is presented. The method is related to the Mino, Sasaki, Tanaka and Quinn and Wald (MiSaTaQuWa) renormalization and to the Detweiler-Whiting construction of the singular field. It relies on the fact that the renormalized ${\ensuremath{\psi}}_{0}$ (or ${\ensuremath{\psi}}_{4}$) is a source-free solution to the Teukolsky equation; and one can therefore reconstruct a nonsingular renormalized metric in a radiation gauge.
Postmortem Retrieval Analysis of Metallosis and Periprosthetic Tissue Metal Concentrations in Total Knee Arthroplasty.

Abstract Background The purpose of this study is to determine the preferred sampling location for tissue analysis in total knee arthroplasty (TKA) and to evaluate metal concentrations, inflammatory cytokines, component damage, and tissue metallosis. Methods Twenty TKA systems were collected at necropsy along with tissue samples from 5 distinct locations. Inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed to determine cobalt (Co), chromium (Cr), and titanium (Ti) concentrations. Synovial fluid cytokine analysis was preformed using a Magnetic Luminex Screening Assay. Femoral components were assesed for damage and tissues were visually scored for metallosis. Results The median metal concentrations were 16 ppb for Co, 46 ppb for Cr, and 9.8 ppb for Ti. There was no association between the tissue collection site and the metal concentration for Co (P = .979), Cr (P = .712), or Ti (P = .854). Twelve of 20 of the necropsy-retrieved TKAs had metallosis, but there was no correlation between Co (P = .48), Cr (P = .89), or Ti (P = .60) concentration and metallosis. Increased Co was associated with decreased tumor necrosis factor alpha (ρ = −0.56, P = .01) and interleukin 1 beta (ρ = −0.48, P = .03). Increased Cr was associated with decreased tumor necrosis factor alpha (ρ= −0.47, P = .03), interleukin 6 (ρ= −0.43, P = .04), and macrophage inflammatory protein 3 alpha (ρ= −0.47, P = .03). Conclusion We observed elevated Co, Cr, and Ti concentrations in tissue from necropsy-retrieved TKA. Our findings did not support the hypothesis that tissue metal concentrations were associated with inflammatory cytokines. The results of this research will be useful for the design of future prospective studies.
Myelodysplastic Syndrome (MDS) Displays Profound and Functionally Significant Epigenetic Deregulation Compared to Acute Myeloid Leukemia (AML) and Normal Bone Marrow Cells.

MDS are a clinically heterogeneous group of clonal disorders, which share a high frequency of progression to secondary AML (MDS-AML). In contrast to de novo AML, MDS and MDS-AML are uniformly resistant to conventional chemotherapy. Among the few active drugs in MDS are the nucleoside analog DNA methyltransferase inhibitors (MTIs) 5-azacytidine and decitabine. Since tumor suppressor genes such as CDKN2B can be silenced by DNA methylation in MDS, it is believed that reversal of DNA methylation by MTIs might contribute to their anti-tumor effects. However, it is not clear whether methylation-dependent silencing of specific genes are predictive of response or even correlate with response to MTIs. Like MDS, AML also presents epigenetic silencing of CDKN2B and other genes; yet appear to not be as sensitive to MTIs. Given the particular sensitivity of MDS to MTIs and its resistance to standard AML chemotherapy, we hypothesized that MDS is a biologically distinct disease from AML due largely to extensive epigenetic deregulation, which is missed by single locus studies. In order to test this we studied DNA methylation levels at 24,000 gene promoters in 13 MDS pts. and 16 de novo normal karyotype AML cases, and compared and contrasted these to CD34+ bone marrow cells from 8 healthy donors. For this we used the HELP (HpaII tiny fragment Enrichment by Ligation-mediated PCR) assay, a robust method for detection of whole-genome DNA methylation, and using MassArray quantitative methylation for single locus validation. Remarkably, MDS was found to have a far greater number of hypermethylated genes than AML or normal CD34+ cells, while AML and CD34+ cells had similar number of methylated genes (MDS vs. AML: 6303 vs. 4177 promoters, p=0.026; MDS vs. normal CD34+ cells: 6303 vs. 4296 promoters, p=0.056). Using a moderated T test, an aberrant methylation signature of 736 genes (p
Achieving Universal Health Coverage (UHC): Dominance analysis across 183 countries highlights importance of strengthening health workforce.

Author(s): Reid, Michael; Gupta, Reena; Roberts, Glenna; Goosby, Eric; Wesson, Paul | Abstract: BACKGROUND:Despite increasing political will to achieve Universal Health Coverage (UHC), there is a paucity of empiric data describing what health system indicators are useful surrogates of country-level progress towards UHC. We sought to determine what public health interventions were useful tracers of country-level UHC progress. METHODS:Across 183 countries we evaluated the extent to which 16 service delivery indicators explained variability in the UHC Service Coverage Index, (UHC SCI) a WHO-validated indicator of country-level health coverage. Dominance analyses, stratifying countries by World Bank income criteria, were used to determine which indicators were most important in in predicting UHC SCI scores. FINDINGS:Health workforce density ranked first overall, provision of basic sanitation and access to clean water ranked second, and provision of basic antenatal services ranked third. In analysis stratified by World Bank income criteria, health workforce density ranked first in Lower Middle Income-Countries (LMICs) (n = 45) and third in Upper Middle Income-Countries (UMICs) (n = 51). CONCLUSIONS:While each country will have a different approach to achieving UHC, strengthening the health workforce will need to be a key priority if they are to be successful in achieving UHC.
Tailored Medication Adherence Incentives Using mHealth for Children With High-Risk Asthma (TAICAM): Protocol for a Randomized Controlled Trial.

Background: Poor adherence to inhaled corticosteroid medications for children with high-risk asthma is both well documented and poorly understood. It has a disproportionate prevalence and impact on children of minority demographics in urban settings. Financial incentives have been shown to be a compelling method to engage those in a high-risk asthma population, but whether adherence can be maintained by offering financial incentives and how these incentives can be used to sustain high adherence are unknown. Objective: The aim of this study is to determine the marginal effects of a financial incentive–based intervention on inhaled corticosteroid adherence, health care system use, and costs. Methods: Participants include children aged 5 to 12 years who have had either at least two hospitalizations or one hospitalization and one emergency department visit for asthma in the year prior to their enrollment (and their caregivers). Participants are given an electronic inhaler sensor in order to track their medication use over a period of 7 months. After a 1-month period of observation, participants are randomized to 1 of 3 arms for a 3-month period. Participants in arm 1 receive daily text message reminders, feedback, and gain–framed, nominal financial incentives; participants in arm 2 receive daily text message reminders and feedback only, and participants in arm 3 receive no reminders, feedback, or incentives. All participants are subsequently observed for an additional 3-month period with no reminders, feedback, or incentives to assess whether any sustained effects are apparent. Results: Study enrollment began in September 2019 with a target sample size of N=125 children. As of June 2020, 61 children have been enrolled. Data collection is estimated to be completed in June 2022, and analyses will be completed by June 2023. Conclusions: This study will provide data that will help to determine whether a financial incentive–based mobile health intervention for promoting inhaled corticosteroid use can be effective in patients with high-risk asthma over longer periods. Trial Registration: Clinicaltrial.gov NCT03907410; https://clinicaltrials.gov/ct2/show/NCT03907410
Learning with immigrant indigenous parents in school and community

In this article I introduce a framework that centers indigenous educational sovereignty in university-school partnerships. Developed from collaborative work with Indigenous Maya families who are mi...
Investigating first-year undergraduate chemistry students’ reasoning with reaction coordinate diagrams when choosing among particulate-level reaction mechanisms

Reaction coordinate diagrams (RCDs) are an important tool used to visualize the energetics of a chemical reaction. RCDs provide information about the kinetics of the reaction, the mechanism by which the reaction occurs, and the relative thermodynamic stability of the molecules in a reaction. Previous research studies have characterized student thinking about chemical kinetics, including their confusion in distinguishing between kinetics and thermodynamics. Semi-structured interviews were conducted with 44 students enrolled in a second-semester, first-year undergraduate chemistry course to elicit students’ ideas about surface features of RCDs and to examine how students connect those surface features to features of particulate-level reaction mechanisms. Students were provided both a gas-phase reaction and its accompanying RCD, and then they were asked to choose the particulate-level reaction mechanism that best corresponded to both the reaction and the RCD from among several possible particulate-level reaction mechanisms. Students were asked to explain their reasoning throughout the interview. Findings include students who chose the correct mechanism with appropriate reasoning, as well as students who chose the correct mechanism yet still expressed inaccurate ideas related to the surface features of RCDs and the concepts encoded within them. Students struggled to explain and reason with surface features such as peaks, valleys, and peak height. Moreover, students frequently found it difficult to identify meaningful connections between these surface features, the stoichiometry of the reaction, and the steps in a reaction mechanism. In addition, many students failed to mention important features of RCDs when describing their reasoning about the connections between particulate-level reaction mechanisms and RCDs. The implications for incorporating these research findings into teaching practices in first-year undergraduate chemistry contexts are discussed.
Zolpidem Versus Trazodone Initiation and the Risk of Fall-Related Fractures among Individuals Receiving Maintenance Hemodialysis.

Background and objectives Zolpidem, a nonbenzodiazepine hypnotic, and trazodone, a sedating antidepressant, are the most common medications used to treat insomnia in the United States. Both drugs have side effect profiles (e.g., drowsiness, dizziness, and cognitive and motor impairment) that can heighten the risk of falls and fractures. Despite widespread zolpidem and trazodone use, little is known about the comparative safety of these medications in patients receiving hemodialysis, a vulnerable population with an exceedingly high fracture rate. Design, setting, participants, & measurements Using data from the United States Renal Data System registry (2013–2016), we conducted a retrospective cohort study to investigate the association between the initiation of zolpidem versus trazodone therapy and the 30-day risk of hospitalized fall-related fractures among Medicare-enrolled patients receiving maintenance hemodialysis. We used an active comparator new-user design and estimated 30-day inverse probability of treatment-weighted hazard ratios and risk differences. We treated death as a competing event. Results A total of 31,055 patients were included: 18,941 zolpidem initiators (61%) and 12,114 trazodone initiators (39%). During the 30-day follow-up period, 101 fall-related fractures occurred. Zolpidem versus trazodone initiation was associated with a higher risk of hospitalized fall-related fracture (weighted hazard ratio, 1.71; 95% confidence interval, 1.11 to 2.63; weighted risk difference, 0.17%; 95% confidence interval, 0.07% to 0.29%). This association was more pronounced among individuals prescribed higher zolpidem doses (hazard ratio, 1.85; 95% confidence interval, 1.10 to 3.01; and risk difference, 0.20%; 95% confidence interval, 0.04% to 0.38% for higher-dose zolpidem versus trazodone; and hazard ratio, 1.60; 95% confidence interval, 1.01 to 2.55 and risk difference, 0.14%; 95% confidence interval, 0.03% to 0.27% for lower-dose zolpidem versus trazodone). Sensitivity analyses using longer follow-up durations yielded similar results. Conclusions Among individuals receiving maintenance hemodialysis, zolpidem initiators had a higher risk of hospitalized fall-related fracture compared with trazodone initiators. Podcast This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_12_18_CJN10070620_final.mp3
Prognostic Value of a Structural Brain MRI Score in the Acute Phase of Aneurysmal Subarachnoid Hemorrhage: A Pilot Study.

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity and mortality despite advances in management. We evaluated the prognostic significance of a qualitative score using brain magnetic resonance imaging (MRI) features obtained early after aSAH. Patients with aSAH were enrolled in a prospective observational cohort and underwent brain MRI during their acute hospitalization. MRIs were rated using a scoring system that considers the anatomical location of signal intensity changes on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences. The relationship between MRI scores and functional outcome defined by modified Rankin scale (mRS) at 6 months was evaluated in uni- and multivariable models. The cohort included 45 aSAH patients (median World Federation of Neurologic Surgeons (IQR) 2 (1–4)) who underwent brain MRI a mean (SD) of 9.0 ± 8.0 days after aSAH. At 6 months after aSAH, 26 patients had achieved a favorable outcome (mRS ≤ 2) while 15 had an unfavorable outcome (mRS > 2). Deep gray nuclei (DGN) score (p = 0.016), cortex + DGN score (p = 0.015), FLAIR score (p = 0.016), DWI score (p = 0.0045), and overall score (p = 0.0081) were significantly lower in patients with favorable outcome compared to those with unfavorable outcome. However, MRI scores were not independent predictors of outcome in multivariable models adjusting for admission Hunt and Hess, Glasgow Coma Scale, or World Federation of Neurologic Surgeons scales. In this pilot study, a qualitative scoring system using anatomically defined MRI FLAIR and DWI signal abnormalities identified in the acute phase of aSAH was linked to 6-month functional outcome. However, these scores did not add prognostic value to established indices of neurological severity.
A successful secession: what does it take to secede?

While a number of movements seek state secession, the majority fails to achieve internationally recognized statehood. What accounts for the success of some secessionist movements and the failure of...
Untreated Insomnia in Corrections and Increased Risk of Death.

Study objectives This review discusses the potential negative consequences of untreated insomnia in correctional settings. Methods A literature review was conducted on the association between insomnia and negative health outcomes, the best practices for treating insomnia with and without medications, and common practices that prohibit the treatment of insomnia in correctional settings. Results Untreated insomnia was associated with increased psychiatric distress, increased risk for suicide, and increased all-cause mortality. Common practices in many correctional institutions impose restrictions on treating insomnia. These practices lead to an increased likelihood for negative health outcomes, including suicide and an increase in all-cause death. Conclusions Practices that prohibit the treatment of sleep in correctional settings increase the risk of death by suicide and other adverse health outcomes. The practices are often put in place due to pressure from the security staff who have trouble controlling the black-market trade of prescribed medications and other contraband within jails and prisons. Healthcare professionals in the correctional setting must advocate for the importance of treating sleep problems in jails and prisons and work with security staff on ways to overcome the problems of pill diversion and the trade of contraband in order to provide quality healthcare to this protected population.
Human Category Learning: Toward a Broader Explanatory Account

Abstract This chapter describes and integrates a set of theoretical and empirical contributions to the psychology of human category learning. A synthesis of computational and behavioral approaches is brought to bear to advance a similarity-based account that rejects the stimulus generalization underpinnings of the reference point view (such as exemplar models) and extends its explanatory scope beyond the circumscribed traditional artificial classification learning (TACL) paradigm. The framework advanced in this chapter emphasizes the role of generative (as opposed to discriminative) category learning and takes its focus in the form of the DIVA model based on a neural network architecture called the divergent autoencoder. Directions and advances that extend beyond TACL include: modes of category learning, item presentation conditions, types of categories, and measures of category representation.
Optimal Cerebral Perfusion Pressure in Head Injury

The lowest Cerebral Perfusion Pressure (CPP) sustainable for days is unknown. An acute reduction in CPP below 45 alters sensorium (Stone et al. 1965, Williams 1968). Cerebral ischemia is reported to occur when CPP falls below 25–30 mmHg (Tyson and Jane 1982). It seems likely that the brain should be more sensitive to prolonged reductions in CPP. Previously published works by the authors show that all severely head injured patients who had a 48-hour CPP below 60 mm Hg died (of 136 patients with severe head injury, 24 fell into this category; Changaris et al. 1988). We sought to determine if early clinical improvement was more frequent when the 48-hr CPP was greater than 80 mmHg.
Processing at immunoglobulin polyadenylation sites in lymphoid cell extracts.

Abstract We have developed an in vitro system for polyadenylation of RNA substrates in cell-free nuclear extracts prepared from murine cells of lymphoid origin. RNA substrates containing the adenovirus L3, murine immunoglobulin (IgM) secreted and membrane polyadenylation sites were accurately polyadenylated in these extracts. Kinetic analysis showed that the rate of polyadenylation in vitro responds proportionally to the substrate concentration. Quantitation of the initial rate of polyadenylation at the three sites permitted comparison of the activities of extracts prepared from HeLa cells, B cells (Wehi 231) and plasmacytoma cells (P9.37.11). From this analysis, we concluded that in all three extracts the polyadenylation activity at the L3 site was higher than that of either of the IgM sites. In contrast to the preferential utilization of the secreted site in vivo in plasmacytomas, this site was not selectively processed in plasmacytoma as compared to B cell extracts. The efficiency of polyadenylation at both IgM sites in the plasmacytoma extract was significantly lower than that in the B cell extract. The common low activity at the IgM sites in the plasmacytoma cell extract suggests that the rate-limiting step for polyadenylation at these two sites differs from that at the L3 site.
Neutron Star Structure and Fundamental Physics

Neutron stars provide a natural laboratory for the study of matter under the most extreme conditions of density, pressure and magnetic fields known. Precise measurements of neutron star masses and radii may provide one of the only means to constrain important aspects of dense matter physics as well as fundamental particle physics. Moreover, neutron stars may contain states of matter not present anywhere else in the observable universe, for example, an exotic color-flavor-locked (CFL), super-fluid quark matter phase. Here, I discuss and review recent efforts to measure neutron star masses and radii in order to use them as probes of fundamental physics. Such efforts have focused on measurements of X-ray pulsation signals from both isolated and accreting neutron stars, as well as observations of the thermal emission from neutron star surfaces. Indeed, recent X-ray observations have provided the first evidence of discrete, redshifted spectral features from neutron star surfaces, which may eventually provide precise mass and radii estimates, however, uncertainties remain in their interpretation. Fast X-ray timing observations of X-ray bursting neutron stars have revealed spin modulation pulsations, and recent studies of “magnetar” giant flares have found fast oscillations which may be signatures of global vibrations of neutron star crusts. I will describe how these observations are yielding new insights on neutron star structure.
TRENDS IN REPEATED LOADS ON TRANSPORT AIRPLANES

Statistical repeated loads data on piston and turbine powered transport aircraft resulting from atmospheric turbulence, maneuvers, landing contact, oscillatory motion, and ground movement
Elevated catecholamine levels and abnormal hypoxic arousal in apnea of infancy.

Arousal from quiet sleep in response to a hypoxic challenge fails to occur in many patients with apnea of infancy. It was hypothesized that catecholamine-mediated responses might be involved in the depressed hypoxic arousal response in apnea of infancy and that these differences would be reflected in serum catecholamine concentrations. Fifteen infants with a median age of 5.5 months and a history of unexplained apnea during sleep were studied. Two hypoxic challenges (PiO2 80 mm Hg) were given for three minutes or until arousal from quiet sleep occurred. Of the 15 patients with apnea of infancy 11 (73%) did not arouse to hypoxia. These infants had serum epinephrine levels that were elevated 4.1-fold while awake (P less than .05), 3.4-fold during quiet sleep (P less than .02), and 3.5-fold during hypoxia (P less than .05). They also had serum norepinephrine levels that were elevated threefold while awake (P less than .05), 5.3-fold during quiet sleep (P less than .001), 3.2-fold during hypoxia (P less than .02), and 12-fold during recovery from hypoxia (P less than .001) in comparison with the corresponding levels in the four (23%) infants who aroused normally to hypoxia. It is speculated that elevated circulating catecholamines are associated with abnormal hypoxic arousal responses in children with apnea of infancy.
Weak production of Λ particles near threshold in electron-proton scattering

We obtain differential cross sections for the reaction ${e}^{\ensuremath{-}}+\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\Lambda}+{\ensuremath{\nu}}_{e},$ for several incident electron energies near threshold. We are motivated to examine this reaction because it has been proposed as a possible experiment at the Thomas Jefferson National Accelerator Facility to measure the electron neutrino mass. We choose electron energies of 194.25 MeV, 195 MeV, 200 MeV, and 205 MeV so that trends in the cross section may be examined. This calculation is phenomenologically based and makes use of $\mathrm{SU}(3)$ relations, and the form factors so obtained accurately describe $\ensuremath{\Lambda}$ beta decay and so should be correct in this region. We obtain contributions of the individual form factors to the differential cross section and show that the axial vector current form factor increasingly dominates as the electron energy nears threshold. Finally we discuss how the behavior of the cross section in the near threshold region affects its use as a tool to study the electron neutrino mass as has recently been proposed.
N-Methylation of Nicotine and Cotinine in Vivo

In studies on the metabolism of randomly labeled ( -)-nicotine-C4 in the anesthetized dog, it has been observed (2, 3) that the major part of the administered radioactivity, approximately 80 to 90$&, appears in the urine. Approximately one-tenth of this radioactivity is present as nicotine. From various experiments in which unlabeled (-)-nicotine and one of its metabolites, (-)-cotinine, have been employed (4-7), it can be deduced that another fraction, approximately one-third, is composed of derivatives of nicotine in which the pyrrolidine ring has undergone fragmentation or oxidative changes. Since N-demethylation of (-)-nicotine leads to carbon dioxide (8), and loss of 2 of the 4 carbon atoms of the pyrrolidine ring leads to 3-pyridylacetic acid (2), many of the urinary metabolites lack unique features and possess only those that are common to the metabolism of 1 and 2 carbon compounds. Indeed, radioactive urea is one of the products of the metabolism of nicotine-methyl-Cl4 in the rat (8). Our attention, therefore, has been directed to metabolites in which the pyridine ring remains intact. During the separation of urinary metabolites arising from randomly labeled ( -)-nicotine-Cl4 administered to the dog, it was observed (2) that the major portion (essentially 95%) of the radioactivity of the urine was retained on Dowex 50 (H+). An exhaustive elution with 4 M ammonia served to remove 65% of the activity from t,he column. Further quantities of radioactivity were removed (1) by elution with strong hydrochloric acid. The material so obtained had properties consistent with those of a strong base. Quaternary ammonium compounds derived from methylation of the pyridine ring of nicotine and its metabolites were at once suggested. The present report describes the isolation and identification of the methonium compounds formed by the biological methylation of the pyridine rings of (-)-nicotine and ( -)-cotinine in oivo.
Evolution of life‐history traits in geographically isolated populations of Vaejovis scorpions (Scorpiones: Vaejovidae)

Geographical isolation can over time accumulate life-history variation which can eventually lead to speciation. We used five species of Vaejovis scorpions that have been isolated from one another since the Pleistocene glaciation to identify if biogeographical patterns have allowed for the accumulation of life-history variation among species. Gravid females were captured and brought back to the lab until giving birth. Once offspring had begun to disperse, measurements of female size, reproductive investment, offspring size, offspring number, and variation in offspring size were recorded. Differences in how each species allocated energy to these variables were analysed utilizing path analysis and structural equation modelling. Female and offspring size, litter size, and total litter mass differed among species, but relative energetic investment did not. Most significant differences among species were not present after removing the effect of female size, indicating that female size is a major source of life-history variation. Path analyses indicated that there was no size–number trade-off within any species and that each species allocates energy toward total litter mass differently. Additionally, as offspring size increased, the variation in offspring mass decreased. These results show that each species allocates the same relative amount of energy in different ways. The variation seen could be a response to environmental variability or uncertainty, a product of maternal effects, or caused by the sufficient accumulation of genetic differences due to geographical isolation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 715–727.
Women and Marketing Education: Bridging the Gap:

Modified experiential techniques enable educators to bridge gaps between classroom and corporation. The process is especially necessary for women, who comprise 50 percent of marketing students. Educators can bring corporations to classrooms via “vignettes” and guest speakers, and bring classes to corporations for interviews, field trips, and corporate panels. Methods can be integrated into existing courses.
Toughness and brittleness of plastics: A summary of an ACS/SPE symposium

A recent and joint ACS/SPE symposium featured 40 papers on the fundamental mechanism of brittle fracture, low-speed crazing and fracture, high-speed impact mechanisms, fatigue failure, multi-phase polymer systems, and reinforcing fibers. A survey of these papers indicates the present state of our knowledge in this field, and the rapid progress it is making toward the development of high-performance plastic materials.
Electromagnetics-Related Aspects of Signaling and Signal Processing for UWB Short Range Radios

A numerical model of the UWB channel created by two dipole antennas is developed to characterize the antennas and the whole channel using system level concepts such as transfer functions in the frequency domain. This model is based on rigorous numerical electromagnetic (EM) analysis, thereby enabling predictions of the channel performance under impact of different antenna geometries, their spatial arrangements, and disturbance caused by diverse factors observable in practical links. These studies of channels address to a number of important issues in electromagnetic-related aspects of UWB signaling schemas and signal processing. First, pulse shaping is developed to support signal transmission across the channel with necessary temporal and spectral features, and high efficiency of energy transmission. To this end, several realistic antennas and practical short-range radio operational scenarios are considered. Second, a system-oriented approach is presented through antenna-signal-circuitry co-design. Finally, overall system performance and hardware complexity of signaling including receiver processing are evaluated.
Photooxidation of 2′-Deoxyguanosine 5′-monophosphate in Aqueous Solution¶

Abstract Mass spectrometric and ultraviolet absorption spectral evidence are presented for the assignment of structures to three products detected in the reaction mixtures formed upon the photolysis of aqueous solutions of the nucleotide 2′-deoxyguanosine 5′-monophosphate (dGMP) with light of wavelengths >270 nm. The products for which structures are assigned are spiroiminodihydantoin 2′-deoxyribonucleotide (1), 2,2-diamino-4-([2-deoxy-5-monophosphate-β-d-erythro-pentofuranosyl]amino)-5-(2H)-oxazolone (oxazolone 2′-deoxyribonucleotide, 2) and 2-amino-5-([2-deoxy-5-monophosphate-β-d-erythro-pentofuranosyl]amino)-4H-imidazol-4-one (imidazolone 2′-deoxyribonucleotide, 3). These results, when combined with mechanistic data presented in an earlier communication, provide support for the proposal that the irradiation of dGMP with UVB light leads to the formation of singlet oxygen. The UV absorption spectral properties of the imidazolone make this product a reasonable candidate to rationalize the autosensitizatio...
Effects of sex steroids on brain beta-endorphin.

Abstract Brain β-endorphin was measured by radioimmunoassay in female rats during different stages of the estrous cycle, during pregnancy, 3 weeks after ovariectomy, and 3 weeks after ovariectomy plus estradiol or estradiol and progesterone replacement. No change in hypothalamic β-endorphin content was noted on the afternoon of diestrus, proestrus, or estrus. However, in 9 rats studied between days 8–20 of pregnancy the mean hypothalamic β-endorphin concentration of41.6 ± 2.24ng/mg protein was significantly higher than the concentration of32.7 ± 1.01 in 21 non-pregnant animals (P We conclude that physiologic concentrations of estradiol and progesterone can alter the content of brain β-endorphin and suggest that ovarian steroids may be important regulators of this brain peptide.
The Oxidative Metabolism of Trypanosoma Lewisi in a Phosphate-Saline Medium

different types of antibodies are formed by the rat in response to infection with T. lewisi. One type of antibody appears early in the infection and inhibits the reproduction of the trypanosomes but allows them to develop into adult individuals. The second type of antibody appears at intervals later in thfe infection and kills varying proportions of the trypanosomes until all are killed and the infection terminated. In order better to understand the mechanism of action of the reproduction-inhibiting and the killing antibodies formed by the rat in response to infection with T. lewisi, the metabolism of these trypanosomes has been studied with particular attention to the possible effects of antibodies upon metabolic processes. The only detailed metabolic studies on these trypanosomes are by Reiner, Smythe, and Pedlow2 and by
Associations between vitamin D deficiency and risk of aggressive breast cancer in African-American women

Although breast cancer incidence in the US is highest for women of European ancestry (EA), women of African ancestry (AA) have higher incidence of cancer diagnosed before age 40 and tumors with more aggressive features (high grade and negative for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (HER2)), which precludes targeted therapies and leads to poorer outcomes. It is unclear what underlies these disparities. It has been hypothesized that dark skin with high melanin content is the ancestral skin color of origin, with adaptation to northern environs resulting in lighter skin. Although intense sunlight in sub-Saharan Africa may compensate for low sun absorption through skin, an urban or western lifestyle may result in less synthesis of vitamin D with higher skin pigmentation. Laboratory and preclinical data indicate that vitamin D is involved in preventing breast carcinogenesis and progression. Vitamin D receptor (VDR) knock-out mice are more likely to develop tumors that are ER-negative, and we have shown that serum levels of 25OHD are lowest among EA women with triple-negative tumors (negative for ER, PR and HER2); and among non-cancer patients, vitamin D levels are lower in AAs than in EAs. Thus, it is plausible to hypothesize that low vitamin D levels could be associated with the higher prevalence of more aggressive tumors among AA women. In this paper, we review the current literature on vitamin D and aggressive breast cancer subtypes, discuss vitamin D in AA women from a perspective of evolution and adaption, and examine the potential role of vitamin D in cancer racial disparities. We present our recently published data showing two single nucleotide polymorphisms in vitamin D catabolic enzyme CYP24A1 associated with higher risk of estrogen ER-negative risk in AA than in EA women. The relationship of vitamin D with breast cancer risk may be subtype-specific, with emerging evidence of stronger effects of vitamin D for more aggressive breast cancer, particularly in women of African ancestry.
When Death Isn't Dead: Implicit Social Rationing during Resuscitative Efforts

In this paper, the author addresses the relationship between social death and clinical-biological death during resuscitative efforts. In Western societies, resuscitative efforts are the medical intervention of choice when sudden death occurs. The widespread use of this technology puts emergency department staff in a difficult gatekeeping position. They are expected to save lives, but, at the same time-when their efforts become futile-to prepare for a dignified death. The author shows that certain groups of patients are much more likely to be considered socially dead regardless of their clinical viability, while others are less likely to be considered socially dead even when irreversible biological death has set in. The result is an implicit rationing of the lifesaving endeavors based on the social worth of the patient. This rationing annihilates initiatives, such as advance directives, which were instituted to empower patients. Social scientists usually suggest that the solution to the negative effects of rationing is to increase accessibility for all populations; however, resuscitative efforts are a prime example in which less access for all groups-instead of for some-might be preferable. This paper is based on observations of 112 resuscitative efforts during a fourteenth-month period and interviews with 42 health care providers.
Visco-Elastohydrodynamic Model of a Hydraulic Rod Seal During Transient Operation

A visco-elastohydrodynamic model of a hydraulic rod seal during transient operation has been developed. The model includes analyses of the macro- and microscale deformation mechanics and contact mechanics, and the microscale fluid mechanics. Viscoelasticity enters the analysis through the deformation mechanics and through the contact mechanics. A hybrid finite element-finite volume computational framework is developed to solve the highly coupled governing equations. Viscoelasticity is seen to affect the leakage and friction characteristics of the seal through its effects on the changing fluid pressure and contact pressure distributions as the rod velocity and sealed pressure change during a cycle. Compared with purely elastic behavior, viscoelasticity increases the fluid pressure and the contact pressure significantly in the sealing region closest to the sealed end, shifts the fluid pressure peaks away from the sealed end during the instroke, and enhances the cavitation during the outstroke. It results in thicker fluid films and produces a significant increase in the Poiseuille flow during the instroke.
HLA-B35 is associated with red cell alloimmunization in sickle cell disease.

HLA-A, -B, -C, and DR antigens were determined in 33 patients with sickle cell disease (SCD), who had received red blood cell (RBC) transfusions. Twenty-one patients formed red cell alloantibodies after transfusions (responders) while 12 multitransfused SCD patients did not form any RBC antibodies (non-responders). We found that 67% of the SCD responder participants had HLA-B35 versus 25% of the non-responders (χ2 = 5.3079, P = 0.0212). The frequency of B35 in non-responder SCD patients was similar to that of a normal healthy Black population consisting of 139 individuals. Calculation of the relative risk showed that sickle cell patients with B35 are six times more likely to form RBC alloantibodies after transfusion than those lacking that HLA antigen. We found no significant increase or association between any HLA-DR antigens and sickle cell disease.
Micromechanics-based structural analysis of thick laminated composites

Abstract Thick filament wound cylinders, or local regions in structural laminates around cut-outs, fasteners or stiffeners may require three-dimensional (3D) analysis and evaluation, in order to fully characterize behavior and evaluate safety margins. This paper describes a particular approach to the 3D structural-level analysis of thick laminated composites that utilizes homogenization concepts and standard displacement-based finite element modeling. Hierarchical material modeling forms the basis of the procedure. The material model consists of two modules: 1. (1) a micro-model of a unidirectional lamina, containing the basic 3D constitutive information for fiber and matrix constituents 2. (2) a sublaminate model that enforces equilibrium of tractions between laminae, and delivers 3D homogenized stresses and strains and material tangent stiffnesses. This integrated approach provides the information required for evaluating damage and failure conditions at the microstructural level, and is essential for nonlinear analysis because of possible interactions between damage and failure modes. A nonlinear elastic material model is formulated, as an example; this nonlinear model, which is suitable for epoxy matrices, has been successfully implemented in a standard finite element code and used quite extensively. However, only elastic analysis results are presented, because the important characteristics of the modeling approach are clearly revealed in this setting. Comparisons are made between material model predictions and analytical, numerical, and experimental results for a unidirectional lamina, a thick laminate, and a thick cylinder under compression and bending. These results show that the accuracy of the procedure for thick laminates is quite satisfactory for practical purposes.