2,750 research outputs found

    A millimeter-wave antireflection coating for cryogenic silicon lenses

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    We have developed and tested an antireflection (AR) coating method for silicon lenses at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR coated flat piece is less than 1.5% at the design wavelength. The coating has been applied to flats and lenses and has survived multiple thermal cycles from 300 to 4 K. We present the manufacturing method, the material properties, the tests performed, and estimates of the loss that can be achieved in practical lenses

    The 10 Meter South Pole Telescope

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    The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966-pixel, multi-color, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2 and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zeldovich effect and to measure the small-scale angular power spectrum of the cosmic microwave background (CMB). The data will be used to characterize the primordial matter power spectrum and to place constraints on the equation of state of dark energy. A second-generation camera will measure the polarization of the CMB, potentially leading to constraints on the neutrino mass and the energy scale of inflation.Comment: 47 pages, 14 figures, updated to match version to be published in PASP 123 903 (May, 2011

    Community screening for left ventricular systolic dysfunction using plasma and urinary natriuretic peptides

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    ObjectivesWe sought to compare urinary and plasma N-terminal pro-brain natriuretic peptide (N-BNP) in left ventricular systolic dysfunction (LVSD) diagnosis.BackgroundPlasma N-BNP is elevated in LVSD. Renal tubule cells produce BNP. We tested the incremental value of urinary N-BNP in LVSD diagnosis.MethodsIn this prospective, community-screening study of undiagnosed LVSD, 1,360 subjects (45 to 80 years of age) were invited, and 1,308 had analyzable echocardiographic scans and urine and plasma specimens. The criterion standard for LVSD was defined as a wall motion score over 1.8 (ejection fraction ≀40%).ResultsTwenty-eight patients with LVSD had elevated urinary and plasma N-BNP levels compared with normal subjects (p < 0.0005). Receiver-operating characteristic (ROC) areas under the curve (AUCs) for urinary and plasma N-BNP were 0.831 and 0.840, respectively. Both tests had high negative predictive values (>99%) for excluding LVSD. Urinary N-BNP was more specific (67.2%) than plasma N-BNP (41%). The plasma/urinary N-BNP product yielded a higher ROC-AUC (0.923) and specificity (78%), reducing the number of cases to scan to detect one case of LVSD to 11.4 (compared with 16.6 [urinary N-BNP] and 29.0 [plasma N-BNP]). Sequential application of tests (urinary N-BNP, then plasma N-BNP in the urine-“positive” cases) achieved similar reductions in the number of cases to scan (10.8), while limiting the number of N-BNP tests to be performed. Urinary N-BNP performed poorly in detection of other cardiac abnormalities with preserved systolic function. It was less costly to test urinary N-BNP in the whole population as compared with other strategies, including scanning high-risk cases with N-BNP testing in the remainder.ConclusionsUrinary N-BNP used together with plasma N-BNP could reduce the echocardiographic burden in screening programs

    A realist view of the canonical EPRB experiment based on quantum theory and its consequences

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    A realist view of the Einstein-Podolsky-Rosen-Bohm experiment with spins based on quantum theory is presented. This view implies that there is no action at a distance. It also implies that the measurement result A (B) for particle 1 (2) depends on both magnet angles, and hence the probability of obtaining the result A (B) also depends on both magnet angles. In light of these realist implications, it is clear that what is wrong at least with local realistic theory is not the locality or no action-at-a-distance assumption itself but rather the formal implementation of that assumption.Comment: To be published in the Journal of Optics B as part of the proceeedings of the Garda 2001 Workshop on Mysteries, Puzzles and Paradoxes in Quantum Mechanic

    High-dose paclitaxel in combination with doxorubicin, cyclophosphamide and peripheral blood progenitor cell rescue in patients with high-risk primary and responding metastatic breast carcinoma: toxicity profile, relationship to paclitaxel pharmacokinetics and short-term outcome

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    We assessed the feasibility and pharmacokinetics of high-dose infusional paclitaxel in combination with doxorubicin, cyclophosphamide, and peripheral blood progenitor cell rescue. Between October 1995 and June 1998, 63 patients with high-risk primary [stage II with ≄ 10 axillary nodes involved, stage IIIA or stage IIIB inflammatory carcinoma (n = 53)] or with stage IV responsive breast cancer (n = 10) received paclitaxel 150–775 mg/m2infused over 24 hours, doxorubicin 165 mg/m2as a continuous infusion over 96 hours, and cyclophosphamide 100 mg kg–1. There were no treatment-related deaths. Dose-limiting toxicity was reversible, predominantly sensory neuropathy following administration of paclitaxel at the 775 mg/m2dose level. Paclitaxel pharmacokinetics were non-linear at higher dose levels; higher paclitaxel dose level, AUC, and peak concentrations were associated with increased incidence of paraesthesias. No correlation between stomatitis, haematopoietic toxicities, and paclitaxel dose or pharmacokinetics was found. Kaplan–Meier estimates of 30-month event-free and overall survival for patients with primary breast carcinoma are 65% (95% CI; 51–83%) and 77% (95% CI; 64–93%). Paclitaxel up to 725 mg/m2infused over 24 hours in combination with with doxorubicin 165 mg/m2and cyclophosphamide 100 mg kg–1is tolerable. A randomized study testing this regimen against high-dose carboplatin, thiotepa and cyclophosphamide (STAMP V) is currently ongoing. © 2001 Cancer Research Campaign http://www.bjcancer.co

    Paraffin-enabled graphene transfer

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    The transfer process of as-grown graphene limits its electrical performance and reliability. Here, the authors develop a transfer approach using paraffin as a support layer and obtain wrinkle-reduced and clean large-area graphene retaining high mobility

    Serous cystic neoplasm of the pancreas: A multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

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    OBJECTIVES: Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality. DESIGN: Retrospective multinational study including SCN diagnosed between 1990 and 2014. RESULTS: 2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58\u2005years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40\u2005mm (2-200)), 9% had resection beyond 1\u2005year of follow-up (3\u2005years (1-20), size at diagnosis: 25\u2005mm (4-140)) and 39% had no surgery (3.6\u2005years (1-23), 25.5\u2005mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1\u2005year (n=1271), size increased in 37% (growth rate: 4\u2005mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1). CONCLUSIONS: After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN
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