401 research outputs found

    Heat-transfer and pressure drop correlations for hydrogen and nitrogen flowing through tungsten wire mesh at temperatures to 5200 deg r

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    Heat transfer and friction pressure drop for forced convection of hydrogen and nitrogen through electrically heated tungsten wire mes

    A 4500 deg R /2500 deg K/ flowing-gas facility

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    High temperature flowing gas heater consisting of four stages for heating gase

    Effective range function below threshold

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    We demonstrate that the kernel of the Lippmann-Schwinger equation, associated with interactions consisting of a sum of the Coulomb plus a short range nuclear potential, below threshold becomes degenerate. Taking advantage of this fact, we present a simple method of calculating the effective range function for negative energies. This may be useful in practice since the effective range expansion extrapolated to threshold allows to extract low-energy scattering parameters: the Coulomb-modified scattering length and the effective range.Comment: 14 pages, 1 figur

    Dispersal-induced social stress prolongs gestation in wild meerkats

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    In the majority of mammals, gestation length is relatively consistent and seldom varies by more than 3%. In a few species, females can adjust gestation length by delaying the development of the embryo after implantation. Delays in embryonic development allow females to defer the rising energetic costs of gestation when conditions are unfavourable, reducing the risk of embryo loss. Dispersal in mammals that breed cooperatively is a period when food intake is likely to be suppressed and stress levels are likely to be high. Here, we show that pregnant dispersing meerkats (Suricata suricatta), which have been aggressively evicted from their natal group and experience weight loss and extended periods of social stress, prolong their gestation by means of delayed embryonic development. Repeated ultrasound scans of wild, unanaesthetized females throughout their pregnancies showed that pregnancies of dispersers were on average 6.3% longer and more variable in length (52–65 days) than those of residents (54–56 days). The variation in dispersers shows that, unlike most mammals, meerkats can adapt to stress by adjusting their pregnancy length by up to 25%. By doing so, they potentially rearrange the costs of gestation during adverse conditions of dispersal and enhance offspring survival

    The PAX5 oncogene is expressed in N-type neuroblastoma cells and increases tumorigenicity of a S-type cell line

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    Neuroblastoma is a neural crest-derived neoplasm of infancy with poor outcome in patients with advanced disease. The oncogenic transcription factor PAX5 is an important developmental regulator and is implicated in the pathogenesis of several malignancies. Screening of neuroblastoma cell lines revealed PAX5 expression in a malignant subset of neuroblastoma cells, so-called ‘N-type' cells, but not in the more benign ‘S-type' neuroblastoma cells. PAX5 expression was also detected in small cell lung cancer, an aggressive tumor of neural crest origin. Based on this observation we hypothesized that there could be a relationship between PAX5 expression and the more malignant phenotype of N-type cells. Stable PAX5 expression was established in several clones of the S-type cell line CA-2E. A noticeable difference in morphology of these transfectants was observed and there was also a significant increase in the proliferation rate. Moreover, PAX5 expressing clones gained the ability to form colonies in a soft agar assay, a marker of tumorigenicity. Down-regulation of PAX5 in several N-type cell lines and one small cell lung cancer cell line utilizing small interfering RNA resulted in a significant decrease in growth rate. Taken together we propose PAX5 as an important factor for the maintenance of the proliferative and tumorigenic phenotype of neuroblastoma. Our data, together with a recent study on the role of PAX genes in cancer suggest that PAX5 and other PAX transcription factors might be valuable targets for cancer therap

    Improved inflammatory bowel disease, wound healing and normal oxidative burst under treatment with empagliflozin in glycogen storage disease type Ib

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    BACKGROUND: Glycogen storage disease type Ib (GSD Ib) is a rare inborn error of glycogen metabolism due to mutations in SLC37A4. Besides a severe form of fasting intolerance, the disorder is usually associated with neutropenia and neutrophil dysfunction causing serious infections, inflammatory bowel disease, oral, urogenital and perianal lesions as well as impaired wound healing. Recently, SGLT2 inhibitors such as empagliflozin that reduce the plasma levels of 1,5-anhydroglucitol have been described as a new treatment option for the neutropenia and neutrophil dysfunction in patients with GSD Ib. RESULTS: We report on a 35-year-old female patient with GSD Ib who had been treated with G-CSF for neutropenia since the age of 9. She had a large chronic abdominal wound as a consequence of recurrent operations due to complications of her inflammatory bowel disease. Treatment with 20 mg empagliflozin per day resulted in normalisation of the neutrophil count and neutrophil function even after termination of G-CSF. The chronic abdominal wound that had been unchanged for 2 years before the start of empagliflozin nearly closed within 12 weeks. No side effects of empagliflozin were observed. CONCLUSION: SGLT2 inhibitors are a new and probably safe treatment option for GSD Ib-associated neutropenia and neutrophil dysfunction. We hypothesize that restoration of neutrophil function and normalisation of neutrophil apoptosis leads to improvement of wound healing and ameliorates symptoms of inflammatory bowel disease

    Dispersal decreases survival but increases reproductive opportunities for subordinates in a cooperative breeder

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    In most socially structured populations, the formation of new groups depends on the survival and reproduction of dispersing individuals. Quantifying vital rates in dispersers, however, is difficult because of the logistic challenges of following wide-ranging animals. Here, using data from free-ranging meerkats (Suricata suricatta),we estimate survival and reproduction of dispersing females and com-pare these estimates to data for established residents. Meerkat groupsconsist of a dominant pair and several subordinate helpers. Female helpers are evicted from their resident groups by the dominant female, allowing her to monopolize reproduction, and evicted females may form small dispersing coalitions. We show that, as in established resident groups, one female is behaviorally dominant in parties of dispersing females. During dispersal and the first 4 months after new group formation, survival is lower for all females compared with established resident groups. At the same time, subordinates in disperser groups have higher birth rates than those in established groups, which rarely breed successfully. This may partly offset the survival costs of dispersal to subordinate females. Further studies of dispersal based on direct observation of dispersing animals are needed to explore the costs and benefits of dispersal in species with contrasting breeding systemsDATA AND CODE AVAILABILITY : Data and code supporting the results of this article have been archived in the Dryad Digital Repository (https://doi.org/10.5061/dryad.jm63xsj85).European Research Council Advanced Grant awards, University of Zurich and MAVA Foundation.http://www.press.uchicago.edu/ucp/journals/journal/an.htmlMammal Research Institut

    Cost of dispersal in a social mammal : body mass loss and increased stress

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    Dispersal is a key process influencing the dynamics of socially and spatially structured populations. Dispersal success is determined by the state of individuals at emigration and the costs incurred after emigration. However, quantification of such costs is often difficult, due to logistical constraints of following wide-ranging individuals. We investigated the effects of dispersal on individual body mass and stress hormone levels in a cooperative breeder, the meerkat (Suricata suricatta). We measured body mass and faecal glucocorticoid metabolite (fGCM) concentrations from 95 dispersing females in 65 coalitions through the entire dispersal process. Females that successfully settled lost body mass, while females that did not settle but returned to their natal group after a short period of time did not. Furthermore, dispersing females had higher fGCM levels than resident females, and this was especially pronounced during the later stages of dispersal. By adding information on the transient stage of dispersal and by comparing dispersers that successfully settled to dispersers that returned to their natal group, we expand on previous studies focusing on the earlier stages of dispersal. We propose that body mass and stress hormone levels are good indicators to investigate dispersal costs, as these traits often play an important role in mediating the effects of the environment on other life-history events and individual fitness.Analyses in this study and data collection at the Kalahari Meerkat Project (KMP) on dispersers were funded by the Swiss National Science Foundation Grant (CR32I3_159743) to A.O., and data collection on resident individuals and maintenance of facilities at the Kalahari Research Centre (KRC) were funded by the ERC Advanced Grants (294494 and 742808) to T.C.-B. and by the University of Zurich.http://royalsocietypublishing.org/journal/rspbhj2019Mammal Research Institut
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