2,339 research outputs found

    Amorphous interface layer in thin graphite films grown on the carbon face of SiC

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    Cross-sectional transmission electron microscopy (TEM) is used to characterize an amorphous layer observed at the interface in graphite and graphene films grown via thermal decomposition of C-face 4H-SiC. The amorphous layer does not to cover the entire interface, but uniform contiguous regions span microns of cross-sectional interface. Annular dark field scanning transmission electron microscopy (ADF-STEM) images and electron energy loss spectroscopy (EELS) demonstrate that the amorphous layer is a carbon-rich composition of Si/C. The amorphous layer is clearly observed in samples grown at 1600{\deg}C for a range of growth pressures in argon, but not at 1500{\deg}C, suggesting a temperature-dependent formation mechanism

    Effect of ovariectomy on the progression of chronic kidney disease-mineral bone disorder (CKD-MBD) in female Cy/+ rats

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    Male Cy/+ rats have shown a relatively consistent pattern of progressive kidney disease development that displays multiple key features of late stage chronic kidney disease-mineral bone disorder (CKD-MBD), specifically the development of cortical bone porosity. However, progression of disease in female Cy/+ rats, assessed in limited studies, is more heterogeneous and to date has failed to show development of the CKD-MBD phenotype, thus limiting their use as a practical model of progressive CKD-MBD. Animal and human studies suggest that estrogen may be protective against kidney disease in addition to its established protective effect on bone. Therefore, in this study, we aimed to determine the effect of ovariectomy (OVX) on the biochemical and skeletal manifestations of CKD-MBD in Cy/+ female rats. We hypothesized that OVX would accelerate development of the biochemical and skeletal features of CKD-MBD in female Cy/+ rats, similar to those seen in male Cy/+ rats. Female Cy/+ rats underwent OVX (n = 8) or Sham (n = 8) surgery at 15 weeks of age. Blood was collected every 5 weeks post-surgery until 35 weeks of age, when the rats underwent a 4-day metabolic balance, and the tibia and final blood were collected at the time of sacrifice. OVX produced the expected changes in trabecular and cortical parameters consistent with post-menopausal disease, and negative phosphorus balance compared with Sham. However, indicators of CKD-MBD were similar between OVX and Sham (similar kidney weight, plasma blood urea nitrogen, creatinine, creatinine clearance, phosphorus, calcium, parathyroid hormone, and no cortical porosity). Contrary to our hypothesis, OVX did not produce evidence of development of the CKD-MBD phenotype in female Cy/+ rats

    Elasticity of smectic liquid crystals with focal conic domains

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    We study the elastic properties of thermotropic smectic liquid crystals with focal conic domains (FCDs). After the application of the controlled preshear at different temperatures, we independently measured the shear modulus G' and the FCD size L. We find out that these quantities are related by the scaling relation G' ~ \gamma_{eff}/L where \gamma_{eff} is the effective surface tension of the FCDs. The experimentally obtained value of \gamma_{\rm eff} shows the same scaling as the effective surface tension of the layered systems \sqrt{KB} where K and B are the bending modulus and the layer compression modulus, respectively. The similarity of this scaling relation to that of the surfactant onion phase suggests an universal rheological behavior of the layered systems with defects.Comment: 14 pages, 7 figures, accepted for publication in JPC

    Improving Human Health by Increasing Access to Natural Areas: Linking Research to Action at Scale

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    Report of the 2014 Berkley Workshop Held at the Wingspread Conference Center, Johnson Foundation, Racine, Wisconsin - June 201

    Multivisceral intestinal transplantation: Surgical pathology

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    We report the diagnostic surgical pathology of two children who underwent multivisceral abdominal transplantation and survived for 1 month and 6 months. There is little relevant literature, and diagnostic criteria for the various clinical possibilities are not established; this is made more complicated by the simultaneous occurrence of more than one process. We based our interpretations on conventional histology, augmented with immunohistology, including HLA staining that distinguished graft from host cells in situ. In some instances functional analysis of T cells propagated from the same biopsies was available and was used to corroborate morphological interpretations. A wide spectrum of changes was encountered. Graft-versus-host disease, a prime concern before surgery, was not seen. Rejection was severe in 1 patient, not present in the other, and both had evidence of lymphoproliferative disease, which was related to Epstein-Barr virus. Bacterial translocation through the gut wall was also a feature in both children. This paper documents and illustrates the various diagnostic possibilities.. © 1989 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

    Force-Extension Relation and Plateau Modulus for Wormlike Chains

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    We derive the linear force-extension relation for a wormlike chain of arbitrary stiffness including entropy elasticity, bending and thermodynamic buckling. From this we infer the plateau modulus G0G^0 of an isotropic entangled solution of wormlike chains. The entanglement length LeL_e is expressed in terms of the characteristic network parameters for three different scaling regimes in the entangled phase. The entanglement transition and the concentration dependence of G0G^0 are analyzed. Finally we compare our findings with experimental data.Comment: 5 pages, 1 eps-figure, to appear in PR

    Development and Testing of Program Evaluation Instruments for the iCook 4-H Curriculum

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    Objective: To develop and test the validity of program outcome evaluation instruments for cooking, eating, and playing together for obesity prevention during iCook 4-H. Design: Instrument development for both youth and adults through pre-post testing of items newly constructed and compiled to address key curriculum constructs. Testing occurred throughout program intervention and dissemination to determine dimensionality, internal consistency and test-retest reliability, and validity. Setting: A 5-state out-of-school program in cooperative extension and other community sites. Participants: Youths aged 9−10 years; adults were main food preparers; the first phase involved 214 dyads and the second phase, 74 dyads. Main Outcome Measure(s): Youth measures were cooking skills, culinary self-efficacy, physical activity, and openness to new foods. Adult measures were cooking together, physical activity, and eating together. Analysis: Exploratory factor analysis to determine initial scale structure and confirmatory factor analysis to confirm factor structures. Longitudinal invariance tests to see whether the factor structure held over time. Test-retest reliability was determined by Pearson r and internal consistency was determined by coefficient V and Cronbach a. Validity testing was determined by Pearson r correlations. Results: Youth cooking skills, openness to new foods, and adult eating together and cooking together showed strong evidence for dimensionality, reliability, and validity. Youth physical activity and adult physical activity measures showed strong evidence for dimensionality and validity but not reliability. The youth culinary selfefficacy measure showed strong evidence for reliability and validity but weaker evidence for dimensionality. Conclusions and Implications: Program outcome evaluation instruments for youths and adults were developed and tested to accompany the iCook 4-H curriculum. Program leaders, stakeholders, and administrators may monitor outcomes within and across programs and generate consistent reporting
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