472 research outputs found

    Shapes, contact angles, and line tensions of droplets on cylinders

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    Using an interface displacement model we calculate the shapes of nanometer-size liquid droplets on homogeneous cylindrical surfaces. We determine effective contact angles and line tensions, the latter defined as excess free energies per unit length associated with the two contact lines at the ends of the droplet. The dependences of these quantities on the cylinder radius and on the volume of the droplets are analyzed.Comment: 26 pages, RevTeX, 10 Figure

    Expression Patterns of Genes Involved in Sugar Metabolism and Accumulation during Apple Fruit Development

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    Both sorbitol and sucrose are imported into apple fruit from leaves. The metabolism of sorbitol and sucrose fuels fruit growth and development, and accumulation of sugars in fruit is central to the edible quality of apple. However, our understanding of the mechanisms controlling sugar metabolism and accumulation in apple remains quite limited. We identified members of various gene families encoding key enzymes or transporters involved in sugar metabolism and accumulation in apple fruit using homology searches and comparison of their expression patterns in different tissues, and analyzed the relationship of their transcripts with enzyme activities and sugar accumulation during fruit development. At the early stage of fruit development, the transcript levels of sorbitol dehydrogenase, cell wall invertase, neutral invertase, sucrose synthase, fructokinase and hexokinase are high, and the resulting high enzyme activities are responsible for the rapid utilization of the imported sorbitol and sucrose for fruit growth, with low levels of sugar accumulation. As the fruit continues to grow due to cell expansion, the transcript levels and activities of these enzymes are down-regulated, with concomitant accumulation of fructose and elevated transcript levels of tonoplast monosaccharide transporters (TMTs), MdTMT1 and MdTMT2; the excess carbon is converted into starch. At the late stage of fruit development, sucrose accumulation is enhanced, consistent with the elevated expression of sucrose-phosphate synthase (SPS), MdSPS5 and MdSPS6, and an increase in its total activity. Our data indicate that sugar metabolism and accumulation in apple fruit is developmentally regulated. This represents a comprehensive analysis of the genes involved in sugar metabolism and accumulation in apple, which will serve as a platform for further studies on the functions of these genes and subsequent manipulation of sugar metabolism and fruit quality traits related to carbohydrates

    Primary mediastinal atypical meningioma: Report of a case and literature review

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    Meningiomas are common neoplasms arising from the central nervous system meninges. On the other hand, primary ectopic meningiomas are extremely rare and usually limited to the head and neck region or to the paravertebral soft tissues. Their occurrence in the mediastinum is even rarer. Until now, only 4 cases of primary mediastinal meningioma have been reported in the literature searched on Medline. Because of its rarity and intriguing pathogenesis, we report here a case of primary mediastinal meningioma that was treated by surgical resection. The clinical features, treatment, pathological findings, and prognosis are analyzed, and the literature on ectopic meningioma is reviewed

    First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph

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    The masses of 246Es, 251Fm, and the transfermium nuclei 249−252Md and 254No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of 246Es and 249,250,252Md were measured for the first time. Using the masses of 249,250Md as anchor points for α decay chains, the masses of heavier nuclei, up to 261Bh and 266Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter ÎŽ2n derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr

    Beta-Delayed fission of 230Am

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    The exotic decay process of ÎČ-delayed fission (ÎČDF) has been studied in the neutron-deficient isotope Am230. The Am230 nuclei were produced in the complete fusion reaction Pb207(Al27,4n)Am230 and separated by using the GARIS gas-filled recoil ion separator. A lower limit for the ÎČDF probability PÎČDF(Am230)>0.30 was deduced, which so far is the highest value among all known ÎČDF nuclei. The systematics of ÎČDF in the region of Am230 will be discussed

    Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --

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    Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the background radiation level of other regions/countries

    Discovery and validation of small-molecule heat-shock protein 90 inhibitors through multimodality molecular imaging in living subjects

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    Up-regulation of the folding machinery of the heat-shock protein 90 (Hsp90) chaperone protein is crucial for cancer progression. The two Hsp90 isoforms (α and ÎČ) play different roles in response to chemotherapy. To identify isoform-selective inhibitors of Hsp90(α/ÎČ)/cochaperone p23 interactions, we developed a dual-luciferase (Renilla and Firefly) reporter system for high-throughput screening (HTS) and monitoring the efficacy of Hsp90 inhibitors in cell culture and live mice. HTS of a 30,176 small-molecule chemical library in cell culture identified a compound, N-(5-methylisoxazol-3-yl)-2-[4-(thiophen-2-yl)-6-(trifluoromethyl)pyrimidin-2-ylthio]acetamide (CP9), that binds to Hsp90(α/ÎČ) and displays characteristics of Hsp90 inhibitors, i.e., degradation of Hsp90 client proteins and inhibition of cell proliferation, glucose metabolism, and thymidine kinase activity, in multiple cancer cell lines. The efficacy of CP9 in disrupting Hsp90(α/ÎČ)/p23 interactions and cell proliferation in tumor xenografts was evaluated by non-invasive, repetitive Renilla luciferase and Firefly luciferase imaging, respectively. At 38 h posttreatment (80 mg/kg × 3, i.p.), CP9 led to selective disruption of Hsp90α/p23 as compared with Hsp90ÎČ/p23 interactions. Small-animal PET/CT in the same cohort of mice showed that CP9 treatment (43 h) led to a 40% decrease in 18F-fluorodeoxyglucose uptake in tumors relative to carrier control-treated mice. However, CP9 did not lead to significant degradation of Hsp90 client proteins in tumors. We performed a structural activity relationship study with 62 analogs of CP9 and identified A17 as the lead compound that outperformed CP9 in inhibiting Hsp90(α/ÎČ)/p23 interactions in cell culture. Our efforts demonstrated the power of coupling of HTS with multimodality molecular imaging and led to identification of Hsp90 inhibitors

    Subcellular concentrations of sugar alcohols and sugars in relation to phloem translocation in Plantago major, Plantago maritima, Prunus persica, and Apium graveolens

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    Sugar and sugar alcohol concentrations were analyzed in subcellular compartments of mesophyll cells, in the apoplast, and in the phloem sap of leaves of Plantago major (common plantain), Plantago maritima (sea plantain), Prunus persica (peach) and Apium graveolens (celery). In addition to sucrose, common plantain, sea plantain, and peach also translocated substantial amounts of sorbitol, whereas celery translocated mannitol as well. Sucrose was always present in vacuole and cytosol of mesophyll cells, whereas sorbitol and mannitol were found in vacuole, stroma, and cytosol in all cases except for sea plantain. The concentration of sorbitol, mannitol and sucrose in phloem sap was 2- to 40-fold higher than that in the cytosol of mesophyll cells. Apoplastic carbohydrate concentrations in all species tested were in the low millimolar range versus high millimolar concentrations in symplastic compartments. Therefore, the concentration ratios between the apoplast and the phloem were very strong, ranging between 20- to 100-fold for sorbitol and mannitol, and between 200- and 2000-fold for sucrose. The woody species, peach, showed the smallest concentration ratios between the cytosol of mesophyll cells and the phloem as well as between the apoplast and the phloem, suggesting a mixture of apoplastic and symplastic phloem loading, in contrast to the herbal plant species (common plantain, sea plantain, celery) which likely exhibit an active loading mode for sorbitol and mannitol as well as sucrose from the apoplast into the phloem
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