322 research outputs found
The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter
The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 μm—the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7–1.6 μm spectral range with a resolving power of ∼20,000. NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a cross-dispersion echelle instrument dedicated to solar occultation measurements in the 2.2–4.4 μm range. MIR achieves a resolving power of >50,000. It has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere. The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7–17 μm with apodized resolution varying from 0.2 to 1.3 cm−1. TIRVIM is primarily dedicated to profiling temperature from the surface up to ∼60 km and to monitor aerosol abundance in nadir. TIRVIM also has a limb and solar occultation capability. The technical concept of the instrument, its accommodation on the spacecraft, the optical designs as well as some of the calibrations, and the expected performances for its three channels are described
Deleterious mutation in the FYB gene is associated with congenital autosomal recessive small-platelet thrombocytopenia
BACKGROUND : The FYB gene encodes adhesion and degranulation-promoting adaptor protein (ADAP), a hematopoietic-specific protein involved in platelet activation, cell motility and proliferation, and integrin-mediated cell adhesion. No ADAP-related diseases have been described in humans, but ADAP-deficient mice have mild thrombocytopenia and increased rebleeding from tail wounds.
PATIENTS AND METHODS : We studied a previously reported family of five children from two consanguineous sibships of Arab Christian descent affected with a novel autosomal recessive bleeding disorder with small-platelet thrombocytopenia. Homozygosity mapping and exome sequencing were used to identify the genetic lesion causing the disease phenotype on chromosome 5. Bone-marrow morphology and platelet function were analyzed. Platelets were characterized by scanning electron microscopy. RESULTS : We identified a homozygous deleterious nonsense mutation, c.393G>A, in FYB. A reduced percentage of mature megakaryocytes was found in the bone marrow. Patients' platelets showed increased basal expression of P-selectin and PAC-1, and reduced increments of activation markers after stimulation with ADP, as detected by flow cytometry; they also showed reduced pseudopodium formation and the presence of trapped platelets between the fibrin fibers after thrombin addition, as observed on scanning electron microscopy. CONCLUSIONS : This is the first report of a disease caused by an FYB defect in humans, manifested by remarkable small-platelet thrombocytopenia and a significant bleeding tendency. The described phenotype shows ADAP to be important for normal platelet production, morphologic changes, and function. It is suggested that mutation analysis of this gene be included in the diagnosis of inherited thrombocytopenia.Academic and Research Committee of Emek Medical Center.http://link.springer.com/journal/11239hb2016Anatom
Association of IL28B SNP With Progression of Egyptian HCV Genotype 4 Patients to End Stage Liver Disease
Virtual Compton Scattering and the Generalized Polarizabilities of the Proton at Q^2=0.92 and 1.76 GeV^2
Virtual Compton Scattering (VCS) on the proton has been studied at Jefferson
Lab using the exclusive photon electroproduction reaction (e p --> e p gamma).
This paper gives a detailed account of the analysis which has led to the
determination of the structure functions P_LL-P_TT/epsilon and P_LT, and the
electric and magnetic generalized polarizabilities (GPs) alpha_E(Q^2) and
beta_M(Q^2) at values of the four-momentum transfer squared Q^2= 0.92 and 1.76
GeV^2. These data, together with the results of VCS experiments at lower
momenta, help building a coherent picture of the electric and magnetic GPs of
the proton over the full measured Q^2-range, and point to their non-trivial
behavior.Comment: version 2: modified according to PRC Editor's and Referee's
recommendations. Archival paper for the E93-050 experiment at JLab Hall A. 28
pages, 23 figures, 5 cross-section tables. To be submitted to Phys.Rev.
Backward electroproduction of pi0 mesons on protons in the region of nucleon resonances at four momentum transfer squared Q**2 = 1.0 GeV**2
Exclusive electroproduction of pi0 mesons on protons in the backward
hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the
forward direction in coincidence with scattered electrons from the 4 GeV
electron beam in Jefferson Lab's Hall A. The data span the range of the total
(gamma* p) center-of-mass energy W from the pion production threshold to W =
2.0 GeV. The differential cross sections sigma_T+epsilon*sigma_L, sigma_TL, and
sigma_TT were separated from the azimuthal distribution and are presented
together with the MAID and SAID parametrizations.Comment: 17 pages, 11 figures, information can be found at
http://hallaweb.jlab.org/experiment/E93-050/vcs.html updated content about
SAID analysis updated MAID results following new reference nucl-th/0310041
updated figure
The reaction dynamics of the 16O(e,e'p) cross section at high missing energies
We measured the cross section and response functions (R_L, R_T, and R_LT) for
the 16O(e,e'p) reaction in quasielastic kinematics for missing energies 25 <=
E_miss <= 120 MeV at various missing momenta P_miss <= 340 MeV/c. For 25 <
E_miss < 50 MeV and P_miss \approx 60 MeV/c, the reaction is dominated by
single-nucleon knockout from the 1s1/2-state. At larger P_miss, the
single-particle aspects are increasingly masked by more complicated processes.
For E_miss > 60 MeV and P_miss > 200 MeV/c, the cross section is relatively
constant. Calculations which include contributions from pion exchange currents,
isobar currents and short-range correlations account for the shape and the
transversity but only for half of the magnitude of the measured cross section.Comment: 6 pages, 4 figures, submitted to Phys Rev Lett, formatting error
fixe
The ratio of proton's electric to magnetic form factors measured by polarization transfer
The ratio of the proton's elastic electromagnetic form factors was obtained
by measuring the transverse and longitudinal polarizations of recoiling protons
from the elastic scattering of polarized electrons with unpolarized protons.
The ratio of the electric to magnetic form factor is proportional to the ratio
of the transverse to longitudinal recoil polarizations. The ratio was measured
over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared.
Simultaneous measurement of transverse and longitudinal polarizations in a
polarimeter provides good control of the systematic uncertainty. The results
for the ratio of the proton's electric to magnetic form factors show a
systematic decrease with increasing four momentum squared, indicating for the
first time a marked difference in the spatial distribution of charge and
magnetization currents in the proton.Comment: 5 pages, 2 figures, version of paper after corrections due to
referees comments and shortened by removing one figure for Physical Review
Letter
Large Momentum Transfer Measurements of the Deuteron Elastic Structure Function A(Q^2) at Jefferson Laboratory
The deuteron elastic structure function A(Q^2) has been extracted in the Q^2
range 0.7 to 6.0 (GeV/c)^2 from cross section measurements of elastic
electron-deuteron scattering in coincidence using the Hall A Facility of
Jefferson Laboratory. The data are compared to theoretical models based on the
impulse approximation with inclusion of meson-exchange currents, and to
predictions of quark dimensional scaling and perturbative quantum
chromodynamicsComment: Submitted to Physical Review Letter
Temozolomide followed by combined immunotherapy with GM-CSF, low-dose IL2 and IFNα in patients with metastatic melanoma
The purpose of this study is to determine the toxicity and efficacy of temozolomide (TMZ) p.o. followed by subcutaneous (s.c.) low-dose interleukin-2 (IL2), granulocyte-monocyte colony stimulating factor (GM-CSF) and interferon-alpha 2b (IFN alpha) in patients with metastatic melanoma. A total of 74 evaluable patients received, in four separate cohorts, escalating doses of TMZ (150-250 mg m(-2)) for 5 days followed by s.c. IL2 (4 MIU m(-2)), GM-CSF (2.5 microg kg(-1)) and IFN alpha (5 MIU flat) for 12 days. A second identical treatment was scheduled on day 22 and cycles were repeated in stable or responding patients following evaluation. Data were analysed after a median follow-up of 20 months (12-30 months). The overall objective response rate was 31% (23 out of 74; confidence limits 20.8-42.9%) with 5% CR. Responses occurred in all disease sites including the central nervous system (CNS). Of the 36 patients with responding or stable disease, none developed CNS metastasis as the first or concurrent site of progressive disease. Median survival was 252 days (8.3 months), 1 year survival 41%. Thrombocytopenia was the primary toxicity of TMZ and was dose- and patient-dependent. Lymphocytopenia (grade 3-4 CTC) occurred in 48.5% (34 out of 70) fully monitored patients following TMZ and was present after immunotherapy in two patients. The main toxicity of combined immunotherapy was the flu-like syndrome (grade 3) and transient liver function disturbances (grade 2 in 20, grade 3 in 15 patients). TMZ p.o. followed by s.c. combined immunotherapy demonstrates efficacy in patients with stage IV melanoma and is associated with toxicity that is manageable on an outpatient basi
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