325 research outputs found

    Production data on 0.55 eV InGaAs thermophotovoltaic cells

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    Low bandgap 0.55 eV (2.25 {micro}m cutoff wavelength) indium gallium arsenide (In{sub 0.72}Ga{sub 0.28}As) thermophotovoltaic (TPV) cells use much more of the long wavelength energy emitted from low temperature (< 1,200 C) thermal sources than either Si or GaSb cells. Data are presented on a statistically significant number (2,500) of these TPV cells, indicating the performance obtainable in large numbers of cells. This data should be useful in the design and modeling of TPV system performance. At 1.2 A/cm{sup 2} short-circuit current, an average open-circuit voltage of 283 mV is obtained with a 60% fill factor. The peak external quantum efficiency for uncoated cells is 65% and is over 50% from 1.1 to 2.2 {micro}m. Internal quantum efficiency is over 76% in this range assuming an estimated 34% reflectance loss

    Audience responses to representations of family-assisted suicide on British television

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    Reflecting on different generic conventions, this study highlights the strengths and weaknesses of documentaries and soap operas in addressing the societal and the personal dimensions of family-assisted suicide. Based on an analysis of YouTube user comments, this study compares how audience members respond to representations of family-assisted suicide in British documentaries and soap operas broadcast between 2010 and 2016. The thematic analysis of comments shows key differences between audience engagement with factual and fictional representations. Markers of a political engagement with this sensitive social issue occur more frequently in comments on documentaries than in comments on soap operas. Comments on soap operas are frequently expressions of emotion, or displays of specialist soap opera knowledge

    Prescribed fire affects female white-tailed deer habitat use during summer lactation

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    a b s t r a c t Prescribed fire commonly is used to manage habitat for white-tailed deer (Odocoileus virginianus). Although the effects of fire on forage availability for deer have been studied, how female deer use burned areas is not well known, particularly as it relates to fire season and the years-since-fire. We used GPS tracking data from 16 adult female white-tailed deer to assess the effects of fire season and yearssince-fire on habitat use during summer lactation. Females selected unburned drainages and older (&gt;1 yr-since-fire) burned areas, and avoided recently burned areas. Individuals with a greater percentage of their summer core area burned expanded the size of their summer home range but did not change summer core area size. Furthermore, summer core area site fidelity (i.e., % overlap between 2011 and 2012 core areas) decreased as the percentage of the 2011 summer core area burned in 2012 increased. Female deer increased selection of burned areas as years-since-fire increased, likely because there was a temporary loss of cover immediately following fire with plants slowly regenerating the subsequent growing seasons. Likewise, to avoid areas depleted of cover, females shifted their core areas away from recent burns when possible but increased their core area size when burned areas were unavoidable (i.e., a large portion of their home range was burned). Burning large contiguous areas may initially have a negative effect on female deer during lactation because of the depletion of cover

    Sensitive periods for the effect of child maltreatment on psychopathology symptoms in adolescence

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    Introduction: Child maltreatment is among the strongest risk factors for mental disorders. However, little is known about whether there are ages when children may be especially vulnerable to its effects. We sought to identify potential sensitive periods when exposure to the 2 most common types of maltreatment (neglect and harsh physical discipline) had a particularly detrimental effect on youth mental health. Methods: Data came from the Future of Families and Child Wellbeing Study (FFCWS), a birth cohort oversampled from “fragile families” (n=3,474). Maltreatment was assessed at 3, 5, and 9 years using an adapted version of the Parent-Child Conflict Tactics Scales (CTS-PC). Using least angle regression, we examined the relationship between repeated measures of exposure to maltreatment on psychopathology symptoms at age 15 (Child Behavior Checklist; CBCL/6-18). For comparison, we evaluated the strength of evidence to support the existence of sensitive periods in relation to an accumulation of risk model. Results: We identified sensitive periods for harsh physical discipline, whereby psychopathology symptom scores were highest among girls exposed at age 9 (r2=0.67 internalizing symptoms; r2=1% externalizing) and among boys exposed at age 5 (r2=0.41%). However, for neglect, the accumulation of risk model explained more variability in psychopathology symptoms for both boys and girls. Conclusion: Child maltreatment may have differential effects based on the child’s sex, type of exposure, and the age it occurs. These findings provide additional evidence for clinicians assessing the benefits and drawbacks of screening efforts and point towards mechanisms driving increased vulnerability to psychopathology

    What Is a Representative Brain? Neuroscience Meets Population Science

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    The last decades of neuroscience research have produced immense progress in the methods available to understand brain structure and function. Social, cognitive, clinical, affective, economic, communication, and developmental neurosciences have begun to map the relationships between neuro-psychological processes and behavioral outcomes, yielding a new understanding of human behavior and promising interventions. However, a limitation of this fast moving research is that most findings are based on small samples of convenience. Furthermore, our understanding of individual differences may be distorted by unrepresentative samples, undermining findings regarding brain–behavior mechanisms. These limitations are issues that social demographers, epidemiologists, and other population scientists have tackled, with solutions that can be applied to neuroscience. By contrast, nearly all social science disciplines, including social demography, sociology, political science, economics, communication science, and psychology, make assumptions about processes that involve the brain, but have incorporated neural measures to differing, and often limited, degrees; many still treat the brain as a black box. In this article, we describe and promote a perspective—population neuroscience—that leverages interdisciplinary expertise to (i) emphasize the importance of sampling to more clearly define the relevant populations and sampling strategies needed when using neuroscience methods to address such questions; and (ii) deepen understanding of mechanisms within population science by providing insight regarding underlying neural mechanisms. Doing so will increase our confidence in the generalizability of the findings. We provide examples to illustrate the population neuroscience approach for specific types of research questions and discuss the potential for theoretical and applied advances from this approach across areas

    Adventage of mesenchymal stem cells (MSC) expansion directly from purified bone marrow CD105^+ and CD271^+ cells

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    Mesenchymal Stem Cells (MSC) are employed in gene and cellular therapies. Routinely MSC are isolated from bone marrow mononuclear cells (MNC) by plastic adherence. Here we compared new isolation strategies of bone marrow MSC including immunodepletion of hematopoietic cells and immunomagnetic isolation of CD105+ and CD271+ populations. Four fractions were obtained: MNC MSC, RosetteSep-isolated MSC, CD105+ and CD271+ sorted MSC. We evaluated i) number of CFU-F colonies, ii) cell phenotype, iii) in vitro differentiation of expanded cells and iv) expression of osteo/adipogenesis related genes. Results: Average number of day 9 CFU-F colonies was the highest for CD271 positive fraction. Real-Time PCR analysis revealed expression of RUNX2, PPARgamma and N-cadherin in isolated cells, particularly high in CD271+ cells. Expression of CD105, CD166, CD44, CD73 antigens was comparable for all expanded populations (over 90%). We observed various levels of hematopoietic contamination with the highest numbers of CD45+ cells in MNC-MSC fraction and the lowest in CD105+ and CD271+ fractions. Cells of all the fractions were CD34 antigen negative. Expanded CD105 and CD271 populations showed higher level of RUNX2, osteocalcin, PTHR, leptin, PPARgamma2 and aggrecan1 genes except for alpha1 collagen. After osteogenic differentiation CD105+ and CD271+ populations showed lower expression of RUNX, PPARgamma2 and also lower expression of osteocalcin and PTHR than MNC, with comparable alpha1-collagen expression. Chondrogenic and adipogenic gene expression was higher in MNC. More clonogenic CD105+ and particularly CD271+ cells, which seem to be the most homogenous fractions based on Real-Time PCR and immunostaining data, are better suited for MSC expansion

    Analysis of Allogenicity of Mesenchymal Stem Cells in Engraftment and Wound Healing in Mice

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    Studies have shown that allogeneic (allo-) bone marrow derived mesenchymal stem cells (BM-MSCs) may enhance tissue repair/regeneration. However, recent studies suggest that immune rejection may occur to allo-MSCs leading to reduced engraftment. In this study, we compared allo-BM-MSCs with syngeneic BM-MSCs or allo-fibroblasts in engraftment and effect in wound healing. Equal numbers of GFP-expressing allo-BM-MSCs, syngeneic BM-MSCs or allo-fibroblasts were implanted into excisional wounds in GFP-negative mice. Quantification of GFP-expressing cells in wounds at 7, 14 and 28 days indicated similar amounts of allogeneic or syngeneic BM-MSCs but significantly reduced amounts of allo-fibroblasts. With healing progression, decreasing amounts of allogeneic and syngeneic BM-MSCs were found in the wound; however, the reduction was more evident (2 fold) in allo-fibroblasts. Similar effects in enhancing wound closure were found in allogeneic and syngeneic BM-MSCs but not in allo-fibroblasts. Histological analysis showed that allo-fibroblasts were largely confined to the injection sites while allo-BM-MSCs had migrated into the entire wound. Quantification of inflammatory cells in wounds showed that allo-fibroblast- but not allo-BM-MSC-treated wounds had significantly increased CD45+ leukocytes, CD3+ lymphocytes and CD8+ T cells. Our study suggests that allogeneic BM-MSCs exhibit ignorable immunogenicity and are equally efficient as syngeneic BM-MSCs in engraftment and in enhancing wound healing

    Reduced Reactivation from Dormancy but Maintained Lineage Choice of Human Mesenchymal Stem Cells with Donor Age

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    Mesenchymal stem cells (MSC) are promising for cell-based regeneration therapies but up to date it is still controversial whether their function is maintained throughout ageing. Aim of this study was to address whether frequency, activation in vitro, replicative function, and in vitro lineage choice of MSC is maintained throughout ageing to answer the question whether MSC-based regeneration strategies should be restricted to younger individuals. MSC from bone marrow aspirates of 28 donors (5–80 years) were characterized regarding colony-forming unit-fibroblast (CFU-F) numbers, single cell cloning efficiency (SSCE), osteogenic, adipogenic and chondrogenic differentiation capacity in vitro. Alkaline phosphatase (ALP) activity, mineralization, Oil Red O content, proteoglycan- and collagen type II deposition were quantified. While CFU-F frequency was maintained, SSCE and early proliferation rate decreased significantly with advanced donor age. MSC with higher proliferation rate before start of induction showed stronger osteogenic, adipogenic and chondrogenic differentiation. MSC with high osteogenic capacity underwent better chondrogenesis and showed a trend to better adipogenesis. Lineage choice was, however, unaltered with age. Conclusion: Ageing influenced activation from dormancy and replicative function of MSC in a way that it may be more demanding to mobilize MSC to fast cell growth at advanced age. Since fast proliferation came along with high multilineage capacity, the proliferation status of expanded MSC rather than donor age may provide an argument to restrict MSC-based therapies to certain individuals

    Investigating the genetic architecture of noncognitive skills using GWAS-by-subtraction

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    Little is known about the genetic architecture of traits affecting educational attainment other than cognitive ability. We used genomic structural equation modeling and prior genome-wide association studies (GWASs) of educational attainment (n = 1,131,881) and cognitive test performance (n = 257,841) to estimate SNP associations with educational attainment variation that is independent of cognitive ability. We identified 157 genome-wide-significant loci and a polygenic architecture accounting for 57% of genetic variance in educational attainment. Noncognitive genetics were enriched in the same brain tissues and cell types as cognitive performance, but showed different associations with gray-matter brain volumes. Noncognitive genetics were further distinguished by associations with personality traits, less risky behavior and increased risk for certain psychiatric disorders. For socioeconomic success and longevity, noncognitive and cognitive-performance genetics demonstrated associations of similar magnitude. By conducting a GWAS of a phenotype that was not directly measured, we offer a view of genetic architecture of noncognitive skills influencing educational success
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