528 research outputs found

    Atmospheric marine boundary layer measurements in the vicinity of San Nicolas Island during CEWCOM-78

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    This is a report on the boundary layer aspects of the NPS participation in CEWCOM-78. The primary purpose of the experiment was to determine how representative San Nicolas Island is of an open ocean marine boundary layer and to examine the validity of boundary layer measurements at the NRL tower on the NW tip of the island. Under favorable wind conditions (NW) the turbulence and profile structure of the boundary layer near SNI was characteristic of typical marine conditions. A comparison of simultaneous measurements at the NRL tower and the R/V ACANIA indicated considerable shoreline influence on the velocity fluctuations (U* or epsilon) and the mean wind speed (U) but essentially no influence on temperature fluctuations (CT2). Using the bulk method to calculate T* and xi from the ACANIA data, the actual measurements of CT2 could be predicted to within about a factor of twoNaval Air Systems Command (AIR 3706) Washington, DC and Naval Ocean Systems Center (EOMET).http://archive.org/details/atmosphericmarin00fairN00019-78-WR-81002, N66001-78-WR-00156NAApproved for public release; distribution is unlimited

    Randomized double-blind clinical trial of a new human epoetin versus a commercially available formula for anemia control in patients on hemodialysis

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    OBJECTIVES: Anemia is a common complication among chronic kidney disease patients on hemodialysis, occurring mostly due to erythropoietin deficiency. This randomized noninferiority trial sought to compare the efficacy and safety of a new epoetin formulation developed by Bio-Manguinhos, a biologics manufacturer affiliated with the Brazilian government, with those of a commercially available product currently used in Brazil (a biosimilar epoetin formulation). METHODS: The sample size needed to enable demonstration of noninferiority with a statistical power of 85% for a between-group difference in hemoglobin levels of no more than 1.5 g/dL was calculated. In total, 74 patients were randomly assigned to receive the epoetin formulation from Bio-Manguinhos (n = 36) or the biosimilar epoetin formulation (n = 38) in a double-blind fashion. The inclusion criteria were current epoetin therapy and stable hemoglobin levels for at least 3 months prior to the study. The primary and secondary outcomes were mean monthly hemoglobin levels and safety, respectively. The dose was calculated according to international criteria and adjusted monthly in both groups according to hemoglobin levels and at the assistant physicians' discretion. Iron storage was estimated at baseline and once monthly. Clinicaltrials.gov: NCT01184495. RESULTS: The study was conducted for 6 months after randomization. The mean baseline hemoglobin levels were 10.9±1.2 and 10.96±1.2 g/dL (p = 0.89) in the Bio-Manguinhos epoetin and biosimilar epoetin groups, respectively. During the study period, there was no significant change in hemoglobin levels in either group (p = 0.055, ANOVA). The epoetin from Bio-Manguinhos was slightly superior in the last 3 months of follow-up. The adverse event profiles of the two formulations were also similar. CONCLUSIONS: The epoetin formulations tested in this study are equivalent in efficacy and safety

    A Complete Version of the Glauber Theory for Elementary Atom - Target Atom Scattering and Its Approximations

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    A general formalism of the Glauber theory for elementary atom (EA) - target atom (TA) scattering is developed. A second-order approximation of its complete version is considered in the framework of the optical-model perturbative approach. A `potential' approximation of a second-order optical model is formulated neglecting the excitation effects of the TA. Its accuracy is evaluated within the second-order approximation for the complete version of the Glauber EA-TA scattering theory.Comment: PDFLaTeX, 10 pages, no figures; an updated versio

    A new approach to high resolution, high contrast electron microscopy of macromolecular block copolymer assemblies

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    Determining the structure of macromolecular samples is vital for understanding and adapting their function. Transmission electron microscopy (TEM) is widely used to achieve this, but, owing to the weak electron scattering cross-section of carbon, TEM images of macromolecular samples are generally low contrast and low resolution. Here we implement a fast and practically simple routine to achieve high-contrast imaging of macromolecular samples using exit wave reconstruction (EWR), revealing a new level of structural detail. This is only possible using ultra-low contrast supports such as the graphene oxide (GO) used here and as such represents a novel application of these substrates. We apply EWR on GO membranes to study self-assembled block copolymer structures, distinguishing not only the general morphology or nanostructure, but also evidence for the substructure (i.e. the polymer chains) which gives insight into their formation mechanisms and functional properties

    Antimatter and Matter Production in Heavy Ion Collisions at CERN (The NEWMASS Experiment NA52)

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    Besides the dedicated search for strangelets NA52 measures light (anti)particle and (anti)nuclei production over a wide range of rapidity. Compared to previous runs the statistics has been increased in the 1998 run by more than one order of magnitude for negatively charged objects at different spectrometer rigidities. Together with previous data taking at a rigidity of -20 GeV/c we obtained 10^6 antiprotons 10^3 antideuterons and two antihelium3 without centrality requirements. We measured nuclei and antinuclei (p,d,antiprotons, antideuterons) near midrapidity covering an impact parameter range of b=2-12 fm. Our results strongly indicate that nuclei and antinuclei are mainly produced via the coalescence mechanism. However the centrality dependence of the antibaryon to baryon ratios show that antibaryons are diminished due to annihilation and breakup reactions in the hadron dense environment. The volume of the particle source extracted from coalescence models agrees with results from pion interferometry for an expanding source. The chemical and thermal freeze-out of nuclei and antinuclei appear to coincide with each other and with the thermal freeze-out of hadrons.Comment: 12 pages, 8 figures, to appear in the proceedings of the conference on 'Fundamental Issues in Elementary Matter' Bad Honnef, Germany, Sept. 25-29, 200

    First πK\pi K atom lifetime and πK\pi K scattering length measurements

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    The results of a search for hydrogen-like atoms consisting of πK±\pi^{\mp}K^{\pm} mesons are presented. Evidence for πK\pi K atom production by 24 GeV/c protons from CERN PS interacting with a nickel target has been seen in terms of characteristic πK\pi K pairs from their breakup in the same target (178±49178 \pm 49) and from Coulomb final state interaction (653±42653 \pm 42). Using these results the analysis yields a first value for the πK\pi K atom lifetime of τ=(2.51.8+3.0)\tau=(2.5_{-1.8}^{+3.0}) fs and a first model-independent measurement of the S-wave isospin-odd πK\pi K scattering length a0=13a1/2a3/2=(0.110.04+0.09)Mπ1\left|a_0^-\right|=\frac{1}{3}\left|a_{1/2}-a_{3/2}\right|= \left(0.11_{-0.04}^{+0.09} \right)M_{\pi}^{-1} (aIa_I for isospin II).Comment: 14 pages, 8 figure

    In Situ SERS Sensing by a Laser-Induced Aggregation of Silver Nanoparticles Templated on a Thermoresponsive Polymer

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    A stimuli-responsive (pH- and thermoresponsive) micelle-forming diblock copolymer, poly(1,2-butadiene) 290 - block -poly( N , N -dimethylaminoethyl methacrylate) 240 (PB- b -PDMAEMA), was used as a polymer template for the in situ synthesis of silver nanoparticles (AgNPs) through Ag + complexation with PDMAEMA blocks, followed by the reduction of the bound Ag + with sodium borohydride. A successful synthesis of the AgNPs on a PB- b -PDMAEMA micellar template was confirmed by means of UV–Vis spectroscopy and transmission electron microscopy, wherein the shape and size of the AgNPs were determined. A phase transition of the polymer matrix in the AgNPs/PB- b -PDMAEMA metallopolymer hybrids, which results from a collapse and aggregation of PDMAEMA blocks, was manifested by changes in the transmittance of their aqueous solutions as a function of temperature. A SERS reporting probe, 4-mercaptophenylboronic acid (4-MPBA), was used to demonstrate a laser-induced enhancement of the SERS signal observed under constant laser irradiation. The local heating of the AgNPs/PB- b -PDMAEMA sample in the laser spot is thought to be responsible for the triggered SERS effect, which is caused by the approaching of AgNPs and the generation of “hot spots” under a thermo-induced collapse and the aggregation of the PDMAEMA blocks of the polymer matrix. The triggered SERS effect depends on the time of a laser exposure and on the concentration of 4-MPBA. Possible mechanisms of the laser-induced heating for the AgNPs/PB- b -PDMAEMA metallopolymer hybrids are discussed

    The NIH-NIAID Filariasis Research Reagent Resource Center

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    Filarial worms cause a variety of tropical diseases in humans; however, they are difficult to study because they have complex life cycles that require arthropod intermediate hosts and mammalian definitive hosts. Research efforts in industrialized countries are further complicated by the fact that some filarial nematodes that cause disease in humans are restricted in host specificity to humans alone. This potentially makes the commitment to research difficult, expensive, and restrictive. Over 40 years ago, the United States National Institutes of Health–National Institute of Allergy and Infectious Diseases (NIH-NIAID) established a resource from which investigators could obtain various filarial parasite species and life cycle stages without having to expend the effort and funds necessary to maintain the entire life cycles in their own laboratories. This centralized resource (The Filariasis Research Reagent Resource Center, or FR3) translated into cost savings to both NIH-NIAID and to principal investigators by freeing up personnel costs on grants and allowing investigators to divert more funds to targeted research goals. Many investigators, especially those new to the field of tropical medicine, are unaware of the scope of materials and support provided by the FR3. This review is intended to provide a short history of the contract, brief descriptions of the fiilarial species and molecular resources provided, and an estimate of the impact the resource has had on the research community, and describes some new additions and potential benefits the resource center might have for the ever-changing research interests of investigators
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