6,421 research outputs found

    Extreme Peripheral Blood Plasmacytosis Mimicking Plasma Cell Leukemia as a Presenting Feature of Angioimmunoblastic T-Cell Lymphoma (AITL).

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    Angioimmunoblastic T-cell lymphoma (AITL) is one of four major subtypes of nodal peripheral T cell lymphoma, characterized by its cell of origin, the follicular helper T-cell (TFH). Patients typically present with prominent constitutional (B) symptoms, generalized lymphadenopathy, hepatosplenomegaly, cytopenias, and rash. Here we present a case of a 62-year-old male with progressive cervical adenopathy, fevers and weight loss presenting with extreme polyclonal plasmacytosis and high plasma EBV viral load. While the initial presentation appeared to mimic plasma cell leukemia or severe infection, lymph node biopsy and bone marrow biopsy confirmed a diagnosis of AITL. This case highlights the heterogeneity of the clinical presentation of AITL to enable physicians to more promptly recognize, diagnose and initiate treatment

    Retention of low-fitness genotypes over six decades of admixture between native and introduced tiger salamanders

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    <p>Abstract</p> <p>Background</p> <p>Introductions of non-native tiger salamanders into the range of California tiger salamanders have provided a rare opportunity to study the early stages of secondary contact and hybridization. We produced first- and second-generation hybrid salamanders in the lab and measured viability among these early-generation hybrid crosses to determine the strength of the initial barrier to gene exchange. We also created contemporary-generation hybrids in the lab and evaluated the extent to which selection has affected fitness over approximately 20 generations of admixture. Additionally, we examined the inheritance of quantitative phenotypic variation to better understand how evolution has progressed since secondary contact.</p> <p>Results</p> <p>We found significant variation in the fitness of hybrids, with non-native backcrosses experiencing the highest survival and F2 hybrids the lowest. Contemporary-generation hybrids had similar survival to that of F2 families, contrary to our expectation that 20 generations of selection in the wild would eliminate unfit genotypes and increase survival. Hybrid survival clearly exhibited effects of epistasis, whereas size and growth showed mostly additive genetic variance, and time to metamorphosis showed substantial dominance.</p> <p>Conclusions</p> <p>Based on first- and second- generation cross types, our results suggest that the initial barrier to gene flow between these two species was relatively weak, and subsequent evolution has been generally slow. The persistence of low-viability recombinant hybrid genotypes in some contemporary populations illustrates that while hybridization can provide a potent source of genetic variation upon which natural selection can act, the sorting of fit from unfit gene combinations might be inefficient in highly admixed populations. Spatio-temporal fluctuation in selection or complex genetics has perhaps stalled adaptive evolution in this system despite selection for admixed genotypes within generations.</p

    The role of religiousness on substance-use disorder treatment outcomes: a comparison of black and white adolescents

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    This study compares 41 Black and 124 White adolescents at intake and discharge from a residential treatment program for substance-use disorders. Study data were obtained as part of a larger study (N = 195) that sought to assess the relationship of helping behavior and addiction recovery. This post-hoc analysis aims to identify cultural strengths that may be associated with recovery from substance-use disorders among Black adolescents. Using regression analyses and controlling for the severity of substance use and background variables that distinguish racial groups, religious practices and behaviors at intake were examined. Specifically, Black youth and White youth were compared on treatment outcomes, including alcohol or drug use during treatment, drug craving, 12-Step work, and 12-Step helping. The burden of health and socioeconomic disparities at intake did not disproportionately disfavor Black adolescents. Outcomes related to 12-Step measures were similar between Black and White youth. White adolescents reported higher craving scores at discharge, and Black adolescents were more likely to use drugs during treatment. High levels of religiousness at treatment intake were linked to greater 12-Step work and greater 12-Step helping at discharge. High levels of religiousness at intake were not related to drug use during treatment or to craving scores at discharge. The relationship between intake levels of religiousness and treatment-related outcomes did not differ by race.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437261/Accepted manuscrip

    Pyridine is an organocatalyst for the reductive ozonolysis of alkenes

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    Whereas the cleavage of alkenes by ozone typically generates peroxide intermediates that must be decomposed in an accompanying step, ozonolysis in the presence of pyridine directly generates ketones or aldehydes through a process that neither consumes pyridine nor generates any detectable peroxides. The reaction is hypothesized to involve nucleophile-promoted fragmentation of carbonyl oxides via formation of zwitterionic peroxyacetals

    High surface area, low weight composite nickel fiber electrodes

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    The energy density and power density of light weight aerospace batteries utilizing the nickel oxide electrode are often limited by the microstructures of both the collector and the resulting active deposit in/on the collector. Heretofore, these two microstructures were intimately linked to one another by the materials used to prepare the collector grid as well as the methods and conditions used to deposit the active material. Significant weight and performance advantages were demonstrated by Britton and Reid at NASA-LeRC using FIBREX nickel mats of ca. 28-32 microns diameter. Work in our laboratory investigated the potential performance advantages offered by nickel fiber composite electrodes containing a mixture of fibers as small as 2 microns diameter (Available from Memtec America Corporation). These electrode collectors possess in excess of an order of magnitude more surface area per gram of collector than FIBREX nickel. The increase in surface area of the collector roughly translates into an order of magnitude thinner layer of active material. Performance data and advantages of these thin layer structures are presented. Attributes and limitations of their electrode microstructure to independently control void volume, pore structure of the Ni(OH)2 deposition, and resulting electrical properties are discussed

    Gender & Sport Related Differences in Electrocardiogram & Pre-Participation Exams (PPE) in College Age Athletes

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    Background and Purpose: The NCAA requires all college level athletes receive a pre-participation physical exam. However, the pre-participation exams occasionally do not require electrocardiogram screening to help detect cardiac abnormalities. Though electrocardiograms may not be available at all testing’s, using specific markers and finding differences between gender and sport abnormalities could help detect cardiac abnormalities. The purpose of this study was to determine if there were significant differences in resting 12-Lead ECG markers in a group NCAA Div. II collegiate level athletes. Methods: Four hundred fifty-one college level athlete’s ages 18 to 25 participated in this study. Age, gender, height, weight, BMI, blood pressure and heart rate were measured during a pre-participation exam. Electrocardiogram measurements were gathered by using Mortara X-Scribe™ , Vacumed Turbo Fit 5™, Welch Allyn CardioPerfect™. Twelve-Lead ECGs were categorized by sport and analyzed by the lab director and the attending physician. One-way ANOVA was used to analyze differences in ECG findings in sports. Independent t-test and linear regression were used to analyze differences between male and female outcomes. Significance was set at the 0.05 level. Results: No significant differences in wave durations were found between male and female athletes. However, P wave amplitude was higher in males (1.50 ± 0.61 mm) than females (1.44 ± .55 mm) (P=0.01). Males had higher resting blood pressures (SBP=123.1 ± 10.9 mmHg) (DBP=73.6 ± 8.1 mmHg) than females (SBP=112.6 ± 9.6 mmHg) (DBP=69.9 ± 7.9 mmHg) (P\u3c0.001). Males also had a higher frequency of arrhythmias, T wave inversions, and 1st degree atrioventricular blocks when compared to females. Similarly, SBP was significantly higher in football compared to all other sports. Relative to ECG parameters cross country athletes showed ECG changes typical for cardiovascular endurance training compared to all other sports including sinus bradycardia, increased RR interval, and leftward axis shift. Discussion: Although marked differences in 12-lead ECG parameters were not found between sports in this sample, two athletes were sent for further echocardiogram evaluation due to abnormal ECGs, but were subsequently cleared to participate in their sport

    On the two-dimensional solution of both adhesive and non-adhesive contact problems involving functionally graded materials

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    This paper presents a semi-analytical algorithm for the determination of the contact half width and surface pressure which results from both adhesive and non-adhesive contact problems involving functionally graded materials (FGM). The inhomogeneously elastic solid comprises a graded elastic coating whose shear modulus depends exponentially on the vertical coordinate and a homogeneously elastic substrate. The solid is assumed to be in a state of plane strain and thus a two-dimensional analysis is performed within this work. Using the work of Chidlow et al. (2011a) as a starting point, we derive a pair of integral equations which may be used to determine approximations to the contact pressure when either the surface deflection or the deflection gradient is known over the contact region. As these integral equations are non-singular, we use Galerkin's method to approximate the contact pressure and it is found that relatively small trial spaces allow accurate computation of the pressure. Information about the prescribed load is then used to formulate an iterative algorithm to determine the contact half width. A selection of numerical results are presented using this method and it is found that the solutions computed here compare favourably with those of other authors. A further investigation is then conducted into the solution of adhesive contact problems using the assumptions of Maugis (1992) and Johnson and Greenwood (2008) to inform the nature of the adhesive stresses outside of the contact. It is found that both JKR-like and DMT-like behaviour can be observed in contact problems involving FGMs
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