1,829 research outputs found

    Optical and evaporative cooling of cesium atoms in the gravito-optical surface trap

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    We report on cooling of an atomic cesium gas closely above an evanescent-wave atom mirror. At high densitities, optical cooling based on inelastic reflections is found to be limited by a density-dependent excess temperature and trap loss due to ultracold collisions involving repulsive molecular states. Nevertheless, very good starting conditions for subsequent evaporative cooling are obtained. Our first evaporation experiments show a temperature reduction from 10muK down to 300nK along with a gain in phase-space density of almost two orders of magnitude.Comment: 8 pages, 6 figures, submitted to Journal of Modern Optics, special issue "Fundamentals of Quantum Optics V", edited by F. Ehlotzk

    Effects of medical history and clinical factors on serum lipase activity and ultrasonographic evidence of pancreatitis: Analysis of 234 dogs

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    Background: Lipase measurements and ultrasonographic (US) evidence of pancreatitis correlate poorly. Objectives: Identify explanations for discrepant lipase and pancreatic US results. Animals: Two hundred and thirty-four dogs with gastrointestinal signs. Methods: A retrospective study was conducted, in which lipase activity and US were performed within 30 hours. Medical history, clinical examination results, lipase activity, and US results were recorded. Results: Lipase and US results were weakly correlated (rs = .25, P 2 days, 118 U/L; P = .03; ≤7 days, 334 U/L; >7 days, 99 U/L; P = .004), but US was not significantly more frequently positive. For both cut-offs (>216/≤216 U/L, >355/≤355 U/L; reference range, 24-108 U/L), median disease duration was significantly shorter (3 vs 4 days) with higher lipases. Previous pancreatitis episodes were significantly associated with an US diagnosis of pancreatitis (P = .04), but median lipase activities were not significantly higher (386 U/L vs 153 U/L; P = .06) in these dogs. Pancreatic US was significantly more often positive when the request contained "suspicion of pancreatitis" (P < .001) or "increased lipase" (P = .01). Only changes in pancreatic morphology, echogenicity, and peripancreatic mesentery were significantly associated with a positive US diagnosis, and also had significantly higher lipase activities. Conclusions and clinical importance: Duration of clinical signs before presentation differently affects laboratory and US evidence of pancreatitis. Previous pancreatitis episodes and information given to radiologists influence US results. These findings can be helpful for future studies on pancreatitis in dogs

    Cold atom gas at very high densities in an optical surface microtrap

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    An optical microtrap is realized on a dielectric surface by crossing a tightly focused laser beam with an horizontal evanescent-wave atom mirror. The nondissipative trap is loaded with \sim10510^5 cesium atoms through elastic collisions from a cold reservoir provided by a large-volume optical surface trap. With an observed 300-fold local increase of the atomic number density approaching 1014cm310^{14}{\rm cm}^{-3}, unprecedented conditions of cold atoms close to a surface are realized

    Evanescent-wave trapping and evaporative cooling of an atomic gas near two-dimensionality

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    A dense gas of cesium atoms at the crossover to two-dimensionality is prepared in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100nK are reached with 20.000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions

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    A Comparison of Methods to Communicate Treatment Preferences in Nursing Facilities: Traditional Practices versus the Physician Orders for Life-Sustaining Treatment (POLST) Program

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    Background Traditional methods to communicate life-sustaining treatment preferences are largely ineffective. The Physician Orders for Life-Sustaining Treatment (POLST) Program offers an alternative approach, but comparative data are lacking. Objectives To evaluate the relationship between communication methods (POLST versus traditional practices) and documentation of life-sustaining treatment orders, symptom assessment and management, and use of life-sustaining treatments. Design Retrospective observational cohort study conducted between June 2006 and April 2007. Setting A stratified, random sample of 90 Medicaid-eligible nursing facilities in Oregon, Wisconsin, and West Virginia. Subjects 1711 living and deceased nursing facility residents aged 65 and older with a minimum 60-day stay. Measurements Life-sustaining treatment orders; pain, shortness of breath, and related treatments over a 7-day period; and use of life-sustaining treatments over a 60-day period. Results POLST users were more likely to have orders about life-sustaining treatment preferences beyond CPR than non-POLST users (98.0% vs. 16.1%, P<.001). There were no differences between POLST users and non-users in symptom assessment or management. POLST users with orders for Comfort Measures Only were less likely to receive medical interventions (e.g., hospitalization) than residents with POLST Full Treatment orders (P=.004), residents with Traditional DNR orders (P<.001), or residents with Traditional Full Code orders (P<.001). Conclusion POLST users were more likely to have treatment preferences documented as medical orders than non-POLST users but there were no differences in symptom management or assessment. POLST orders restricting medical interventions were associated with the lower use of life-sustaining treatments. Findings suggest the POLST program offers significant advantages over traditional methods to communicate preferences about life-sustaining treatments

    MicroRNA Expression Profile in the Vitreous of Proliferative Diabetic Retinopathy Patients and Differences from Patients Treated with Anti-VEGF

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    Purpose: microRNAs (miRNAs) mediate the pathological mechanisms of diabetic retinopathy. In this study, we compared miRNA expression profiles in the vitreous between patients with proliferative diabetic retinopathy (PDR) and patients with a macular hole as non-diabetic controls, and between PDR patients treated with antivascular endothelial growth factor (VEGF) therapy and untreated PDR patients. Methods: Vitreous samples of non-diabetic and PDR patients were screened for miRNAs with quantitative polymerase chain reaction (qPCR) panels. miRNA candidates were validated in vitreous samples of a second, independent cohort. In addition, the effect of anti-VEGF therapy was investigated in the vitreous of a third study population consisting of PDR patients who had not received anti-VEGF therapy and PDR patients who had received preoperative anti-VEGF therapy. Results: During screening, seven miRNAs were found to be significantly higher in the vitreous of PDR patients, whereas two miRNAs were found to be significantly lower compared with non-diabetic controls. Validating the expression of these miRNAs in a second cohort resulted in the identification of six miRNAs that were expressed at significantly higher rates in the vitreous of PDR patients: hsa-miR-20a-5p, hsa-miR-23b3p, hsa-miR-142-3p, hsa-miR-185-5p, hsa-miR-326, and hsa-miR-362-5p. Among these six miRNAs, hsa-miR-23b-3p levels were lower in the anti-VEGF-treated group of PDR patients compared with untreated PDR patients. Conclusions: In this study, we identified six miRNAs that are expressed more highly in PDR patients and one miRNA that is expressed at a lower levels in anti-VEGF-treated PDR patients. Translational Relevance: miRNAs identified in the vitreous of PDR patients may improve our understanding of the mechanisms leading to PDR
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