9,713 research outputs found
Field ionization electrodes Patent
Electrodes having array of small surfaces for field ionizatio
DichroMatch: a website for similarity searching of circular dichroism spectra
Circular dichroism (CD) spectroscopy is a widely used method for examining the structure, folding and conformational changes of proteins. A new online CD analysis server (DichroMatch) has been developed for identifying proteins with similar spectral characteristics by detecting possible structurally and functionally related proteins and homologues. DichroMatch includes six different methods for determining the spectral nearest neighbours to a query protein spectrum and provides metrics of how similar these spectra are and, if corresponding crystal structures are available for the closest matched proteins, information on their secondary structures and fold classifications. By default, DichroMatch uses all the entries in the Protein Circular Dichroism Data Bank (PCDDB) for its comparison set, providing the broadest range of publicly available protein spectra to match with the unknown protein. Alternatively, users can download or create their own specialized data sets, thereby enabling comparisons between the structures of related proteins such as wild-type versus mutants or homologues or a series of spectra of the same protein under different conditions. The DichroMatch server is freely available at http://dichromatch.cryst.bbk.ac.uk
Single Maximal versus Combination Punch Kinematics
The aim of this study was to determine the influence of punch type (Jab, Cross, Lead Hook and Reverse Hook) and punch modality (Single maximal, ‘In-synch’ and ‘Out of synch’ combination) on punch speed and delivery time. Ten competition-standard volunteers performed punches with markers placed on their anatomical landmarks for 3D motion capture with an eight-camera optoelectronic system. Speed and duration between key moments were computed. There were significant differences in contact speed between punch types (F 2,18,84.87 = 105.76, p = 0.001) with Lead and Reverse Hooks developing greater speed than Jab and Cross. There were significant differences in contact speed between punch modalities (F 2,64,102.87 = 23.52, p = 0.001) with the Single maximal (M ± SD: 9.26 ± 2.09 m/s) higher than ‘Out of synch’ (7.49 ± 2.32 m/s), ‘In-synch’ left (8.01 ± 2.35 m/s) or right lead (7.97 ± 2.53 m/s). Delivery times were significantly lower for Jab and Cross than Hook. Times were significantly lower ‘In-synch’ than a Single maximal or ‘Out of synch’ combination mode. It is concluded that a defender may have more evasion-time than previously reported. This research could be of use to performers and coaches when considering training preparations
The order-disorder transition in colloidal suspensions under shear flow
We study the order-disorder transition in colloidal suspensions under shear
flow by performing Brownian dynamics simulations. We characterize the
transition in terms of a statistical property of time-dependent maximum value
of the structure factor. We find that its power spectrum exhibits the power-law
behaviour only in the ordered phase. The power-law exponent is approximately -2
at frequencies greater than the magnitude of the shear rate, while the power
spectrum exhibits the -type fluctuations in the lower frequency regime.Comment: 11 pages, 10 figures, v.2: We have made some small improvements on
presentation
Mismatch-based delayed thrombolysis: a meta-analysis
<p><b>Background and Purpose</b>: Clinical benefit from thrombolysis is reduced as stroke onset to treatment time increases. The use of "mismatch" imaging to identify patients for delayed treatment has face validity and has been used in case series and clinical trials. We undertook a meta-analysis of relevant trials to examine whether present evidence supports delayed thrombolysis among patients selected according to mismatch criteria.</p>
<p><b>Methods</b>: We collated outcome data for patients who were enrolled after 3 hours of stroke onset in thrombolysis trials and had mismatch on pretreatment imaging. We selected the trials on the basis of a systematic search of the Web of Knowledge. We compared favorable outcome, reperfusion and/or recanalization, mortality, and symptomatic intracerebral hemorrhage between the thrombolyzed and nonthrombolyzed groups of patients and the probability of a favorable outcome among patients with successful reperfusion and clinical findings for 3 to 6 versus 6 to 9 hours from poststroke onset. Results are expressed as adjusted odds ratios (a-ORs) with 95% CIs. Heterogeneity was explored by test statistics for clinical heterogeneity, I2 (inconsistency), and L’Abbé plot.</p>
<p><b>Results</b>: We identified articles describing the DIAS, DIAS II, DEDAS, DEFUSE, and EPITHET trials, giving a total of 502 mismatch patients thrombolyzed beyond 3 hours. The combined a-ORs for favorable outcomes were greater for patients who had successful reperfusion (a-OR=5.2; 95% CI, 3 to 9; I2=0%). Favorable clinical outcome was not significantly improved by thrombolysis (a-OR=1.3; 95% CI, 0.8 to 2.0; I2=20.9%). Odds for reperfusion/recanalization were increased among patients who received thrombolytic therapy (a-OR=3.0; 95% CI, 1.6 to 5.8; I2=25.7%). The combined data showed a significant increase in mortality after thrombolysis (a-OR=2.4; 95% CI, 1.2 to 4.9; I2=0%), but this was not confirmed when we excluded data from desmoteplase doses that were abandoned in clinical development (a-OR=1.6; 95% CI, 0.7 to 3.7; I2=0%). Symptomatic intracerebral hemorrhage was significantly increased after thrombolysis (a-OR=6.5; 95% CI, 1.2 to 35.4; I2=0%) but not significant after exclusion of abandoned doses of desmoteplase (a-OR=5.4; 95% CI, 0.9 to 31.8; I2=0%).</p>
<p><b>Conclusions</b>: Delayed thrombolysis amongst patients selected according to mismatch imaging is associated with increased reperfusion/recanalization. Recanalization/reperfusion is associated with improved outcomes. However, delayed thrombolysis in mismatch patients was not confirmed to improve clinical outcome, although a useful clinical benefit remains possible. Thrombolysis carries a significant risk of symptomatic intracerebral hemorrhage and possibly increased mortality. Criteria to diagnose mismatch are still evolving. Validation of the mismatch selection paradigm is required with a phase III trial. Pending these results, delayed treatment, even according to mismatch selection, cannot be recommended as part of routine care.</p>
Mass transport of an impurity in a strongly sheared granular gas
Transport coefficients associated with the mass flux of an impurity immersed
in a granular gas under simple shear flow are determined from the inelastic
Boltzmann equation. A normal solution is obtained via a Chapman-Enskog-like
expansion around a local shear flow distribution that retains all the
hydrodynamic orders in the shear rate. Due to the anisotropy induced by the
shear flow, tensorial quantities are required to describe the diffusion process
instead of the conventional scalar coefficients. The mass flux is determined to
first order in the deviations of the hydrodynamic fields from their values in
the reference state. The corresponding transport coefficients are given in
terms of the solutions of a set of coupled linear integral equations, which are
approximately solved by considering the leading terms in a Sonine polynomial
expansion. The results show that the deviation of these generalized
coefficients from their elastic forms is in general quite important, even for
moderate dissipation.Comment: 6 figure
NXY-059 for the treatment of acute stroke: pooled analysis of the SAINT I and II trials
<p><b>Background and Purpose:</b> In animal models of acute ischemic stroke (AIS), the free radical-trapping agent NXY-059 showed promise as a neuroprotectant. SAINT I and II were randomized, placebo-controlled, double-blind trials to investigate the efficacy of NXY-059 in patients with AIS.</p>
<p><b>Methods:</b> Patients with AIS received an infusion of intravenous NXY-059 or placebo within 6 hours from the onset of stroke symptoms. A pooled individual patient analysis was prespecified to assess the overall efficacy and to examine subgroups. The primary end point was the distribution of disability scores measured on the modified Rankin scale (mRS) at 90 days. Neurologic and activities of daily living scores were investigated as secondary end points. We also evaluated whether treatment with NXY-059 would reduce alteplase-related intracranial hemorrhages. Finally, we evaluated possible predictors of good or poor outcome.</p>
<p><b>Results:</b> An intent-to-treat efficacy analysis was based on 5028 patients. Baseline parameters and prognostic factors were well balanced between treatment groups. The distribution of scores on the mRS was not different in the group treated with NXY-059 (n = 2438) compared with the placebo group (n = 2456): odds ratio for limiting disability = 1.02; 95% CI, 0.92 to 1.13 (P = 0.682, Cochran-Mantel-Haenszel test). Comparisons at each level of the mRS confirmed an absence of benefit. There was no evidence of efficacy in prespecified subgroups or from the secondary outcome analyses. Mortality was equal in the 2 groups (16.7% vs 16.5%), and adverse event rates were similar. Among patients treated with alteplase, there was no decrease in rates of symptomatic or asymptomatic hemorrhage associated with NXY-059 treatment versus placebo. Subgroup analyses identified National Institutes of Health Stroke Scale score, age, markers of inflammation, blood glucose, and right-sided infarct as predictors of poor outcome.</p>
<p><b>Conclusions:</b> NXY-059 is ineffective for treatment of AIS within 6 hours of symptom onset. This is also true for subgroups and the prevention of alteplase-associated hemorrhage.</p>
Additional outcomes and subgroup analyses of NXY-059 for acute ischemic stroke in the SAINT I trial
<p><b>Background and Purpose:</b> NXY-059 is a free radical-trapping neuroprotectant demonstrated to reduce disability from ischemic stroke. We conducted analyses on additional end points and sensitivity analyses to confirm our findings.</p>
<p><b>Methods:</b> We randomized 1722 patients with acute ischemic stroke to a 72-hour infusion of placebo or intravenous NXY-059 within 6 hours of stroke onset. The primary outcome was disability at 90 days, as measured by the modified Rankin Scale (mRS), a 6-point scale ranging from 0 (no residual symptoms) to 5 (bed-bound, requiring constant care). Additional and exploratory analyses included mRS at 7 and 30 days; subgroup interactions with final mRS; assessments of activities of daily living by Barthel index; and National Institutes of Health Stroke Scale (NIHSS) neurological scores at 7 and 90 days.</p>
<p><b>Results:</b> NXY-059 significantly improved the distribution of the mRS disability score compared with placebo at 7, 30, and 90 days (Cochran-Mantel-Haenszel test P=0.002, 0.004, 0.038, respectively; 90-day common odds ratio 1.20; 95% CI, 1.01 to 1.42). The benefit was not attributable to any specific baseline characteristic, stratification variable or subgroup interaction. Neurological scores were improved at 7 days (odds ratio [OR], 1.46; 95% CI, 1.13, 1.89; P=0.003) and the Barthel index was improved at 7 and 30 days (OR, 1.55; 95% CI, 1.22, 1.98; P<0.0001; OR, 1.27; 95% CI, 1.01, 1.59; P=0.02).</p>
<p><b>Conclusions:</b> NXY-059 within 6 hours of acute ischemic stroke significantly reduced disability. Benefit on neurological scores and activities of daily living was detectable early but not significant at 90 days; however, our trial was underpowered to measure effects on the neurological examination. The benefit on disability is not confounded by interactions and is supported by other outcome measures.</p>
Structure and superconductivity of two different phases of Re3W
Two superconducting phases of Re(3)W have been found with different physical properties. One phase crystallizes in a noncentrosymmetric cubic (alpha-Mn) structure and has a superconducting transition temperature T(c) of 7.8 K. The other phase has a hexagonal centrosymmetric structure and is superconducting with a T(c) of 9.4 K. Switching between the two phases is possible by annealing the sample or remelting it. The properties of both phases of Re(3)W have been characterized by powder neutron diffraction, magnetization, and resistivity measurements. The temperature dependences of the lower and upper critical fields have been measured for both phases. These are used to determine the penetration depths and the coherence lengths for these systems
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