2,915 research outputs found
Performance of an Anode Supported Solid Oxide Fuel Cell with Indirect Internal Reforming
The conversion of fuel into hydrogen-rich gas is necessary for fuel cells. This can be achieved either indirectly in fuel processing systems, in which the hydrocarbon feed is converted in an external catalytic steam reformer, or directly in the fuel cell. In this paper, the unit module of solid oxide fuel cell was assembled by one reformer and four cells. The reformer was fabricated by extruded dummy cell and combined with two cells on each side respectively. The reforming catalyst was coated on internal channel of the dummy cell. The unit module has successfully tested with wet CH4 as fuel and air as oxidant and its maximum power density exceeded 150mW/cm(2) at 750 degrees C.open110Nsciescopu
Suppressing Impacts of the Amazonian Deforestation by the Global Circulation Change
Analyzing the Global Historical Climatology Network, outgoing longwave radiation, and NCEP–NCAR reanalysis data over the Amazon Basin, the authors find a clear interdecadal increasing trend over the past four decades in both rainfall and intensity of the hydrological cycle. These interdecadal variations are a result of the interdecadal change of the global divergent circulation. On the contrary, the impact of the Amazon deforestation as evaluated by all numerical studies has found a reduction of rainfall and evaporation, and an increase of temperature in the Amazon Basin extending its dry season. Evidently, the interdecadal trend of the basin\u27s hydrological cycle revealed from observations functions in a course opposite to the deforestation scenario. Results of this study suggest that future studies analyzing the impact of the basin–scale deforestation on the regional hydrological cycle and climate should be reassessed with multidecade numerical simulations including both schemes handling the land–surface processes and the mechanism generating proper interdecadal variation of the global divergent circulation
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Roundup 2.0: Enabling Comparative Genomics for over 1800 Genomes
Summary: Roundup is an online database of gene orthologs for over 1800 genomes, including 226 Eukaryota, 1447 Bacteria, 113 Archaea, and 21 Viruses. Orthologs are inferred using the Reciprocal Smallest Distance algorithm. Users may query Roundup for single-linkage clusters of orthologous genes based on any group of genomes. Annotated query results may be viewed in a variety of ways including as clusters of orthologs and as phylogenetic profiles. Genomic results may be downloaded in formats suitable for functional as well as phylogenetic analysis, including the recent OrthoXML standard. In addition, gene IDs can be retrieved using FASTA sequence search. All orthology results and source code are freely available
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Autworks: a Cross-Disease Network Biology Application for Autism and Related Disorders
Background: The genetic etiology of autism is heterogeneous. Multiple disorders share genotypic and phenotypic traits with autism. Network based cross-disorder analysis can aid in the understanding and characterization of the molecular pathology of autism, but there are few tools that enable us to conduct cross-disorder analysis and to visualize the results. Description: We have designed Autworks as a web portal to bring together gene interaction and gene-disease association data on autism to enable network construction, visualization, network comparisons with numerous other related neurological conditions and disorders. Users may examine the structure of gene interactions within a set of disorder-associated genes, compare networks of disorder/disease genes with those of other disorders/diseases, and upload their own sets for comparative analysis. Conclusions: Autworks is a web application that provides an easy-to-use resource for researchers of varied backgrounds to analyze the autism gene network structure within and between disorders
Xenopus staufen2 is required for anterior endodermal organ formation
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in genesis 50 (2012): 251-259, doi:10.1002/dvg.22000.Defining the regulatory molecular networks involved in patterning the developing anterior endoderm is essential to understanding how the pancreas, liver, stomach and duodenum are discretely specified from each other. In this study, we analyzed the expression and function of the double-stranded RNA-binding protein Staufen2 in Xenopus laevis endoderm. We found that staufen2 was broadly expressed within the developing endoderm beginning at gastrulation becoming localized to the anterior endoderm at later stages. Through morpholino-mediated knockdown, we demonstrate that Staufen2 function is required for proper formation of the stomach, liver and pancreas. We define that its function is required during gastrulation for proper patterning of the dorsal-ventral axis and that it acts to regulate expression of BMP signaling components.This work was supported by grants from the National Institutes of Health (DK077197) to M.E.H. and from the Canadian Institute of Health Research (Frederick Banting and Charles Best Canada Graduate Scholarships - Doctoral Awards) to C.K.B
Appetite suppressants and valvular heart disease - a systematic review
Background Although appetite suppressants have been implicated in the development of valvular heart disease, the exact level of risk is still uncertain. Initial studies suggested that as many as 1 in 3 exposed patients were affected, but subsequent research has yielded substantially different figures. Our objective was to systematically assess the risk of valvular heart disease with appetite suppressants. Methods We accepted studies involving obese patients treated with any of the following appetite suppressants: fenfluramine, dexfenfluramine, and phentermine. Three types of studies were reviewed: controlled and uncontrolled observational studies, and randomized controlled trials. Outcomes of interest were echocardiographically detectable aortic regurgitation of mild or greater severity, or mitral regurgitation of moderate or greater severity. Results Of the 1279 patients evaluated in seven uncontrolled cohort studies, 236 (18%) and 60 (5%) were found to have aortic and mitral regurgitation, respectively. Pooled data from six controlled cohort studies yielded, for aortic regurgitation, a relative risk ratio of 2.32 (95% confidence intervals 1.79 to 3.01, p < 0.00001) and an attributable rate of 4.9%, and for mitral regurgitation, a relative risk ratio of 1.55 (95% confidence intervals 1.06 to 2.25, p = 0.02) with an attributable rate of 1.0%. Only one case of valvular heart disease was detected in 57 randomized controlled trials, but this was judged unrelated to drug therapy. Conclusions The risk of valvular heart disease is significantly increased by the appetite suppressants reviewed here. Nevertheless, when considering all the evidence, valvulopathy is much less common than suggested by the initial, less methodologically rigorous studies
Surgeon Preference Regarding Wound Dressing Management in Lumbar Fusion Surgery: An AO Spine Global Cross-Sectional Study.
OBJECTIVE: To evaluate the global practice pattern of wound dressing use after lumbar fusion for degenerative conditions. METHODS: A survey issued by AO Spine Knowledge Forums Deformity and Degenerative was sent out to AO Spine members. The type of postoperative dressing employed, timing of initial dressing removal, and type of subsequent dressing applied were investigated. Differences in the type of surgery and regional distribution of surgeons' preferences were analyzed. RESULTS: Right following surgery, 60.6% utilized a dry dressing, 23.2% a plastic occlusive dressing, 5.7% glue, 6% a combination of glue and polyester mesh, 2.6% a wound vacuum, and 1.2% other dressings. The initial dressing was removed on postoperative day 1 (11.6%), 2 (39.2%), 3 (20.3%), 4 (1.7%), 5 (4.3%), 6 (0.4%), 7 or later (12.5%), or depending on drain removal (9.9%). Following initial dressing removal, 75.9% applied a dry dressing, 17.7% a plastic occlusive dressing, and 1.3% glue, while 12.1% used no dressing. The use of no additional coverage after initial dressing removal was significantly associated with a later dressing change (p < 0.001). Significant differences emerged after comparing dressing management among different AO Spine regions (p < 0.001). CONCLUSION: Most spine surgeons utilized a dry or plastic occlusive dressing initially applied after surgery. The first dressing was more frequently changed during the first 3 postoperative days and replaced with the same type of dressing. While dressing policies tended not to vary according to the type of surgery, regional differences suggest that actual practice may be based on personal experience rather than available evidence
Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke
Background
Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared
the efficacy and safety of two antiplatelet regimens — aspirin plus extendedrelease
dipyridamole (ASA–ERDP) versus clopidogrel.
Methods
In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive
25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive
75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke.
The secondary outcome was a composite of stroke, myocardial infarction, or death
from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075),
followed by superiority testing, was planned.
Results
A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke
occurred in 916 patients (9.0%) receiving ASA–ERDP and in 898 patients (8.8%) receiving
clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The
secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for
ASA–ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events
among ASA–ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365
[3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage
(hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major
hemorrhagic event was similar in the two groups (1194 ASA–ERDP recipients [11.7%],
vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11).
Conclusions
The trial did not meet the predefined criteria for noninferiority but showed similar rates
of recurrent stroke with ASA–ERDP and with clopidogrel. There is no evidence that either
of the two treatments was superior to the other in the prevention of recurrent
stroke. (ClinicalTrials.gov number, NCT00153062.
Multi-site campaign for transit timing variations of WASP-12 b: possible detection of a long-period signal of planetary origin
The transiting planet WASP-12 b was identified as a potential target for
transit timing studies because a departure from a linear ephemeris was reported
in the literature. Such deviations could be caused by an additional planet in
the system. We attempt to confirm the existence of claimed variations in
transit timing and interpret its origin. We organised a multi-site campaign to
observe transits by WASP-12 b in three observing seasons, using 0.5-2.6-metre
telescopes. We obtained 61 transit light curves, many of them with
sub-millimagnitude precision. The simultaneous analysis of the best-quality
datasets allowed us to obtain refined system parameters, which agree with
values reported in previous studies. The residuals versus a linear ephemeris
reveal a possible periodic signal that may be approximated by a sinusoid with
an amplitude of 0.00068+/-0.00013 d and period of 500+/-20 orbital periods of
WASP-12 b. The joint analysis of timing data and published radial velocity
measurements results in a two-planet model which better explains observations
than single-planet scenarios. We hypothesize that WASP-12 b might be not the
only planet in the system and there might be the additional 0.1 M_Jup body on a
3.6-d eccentric orbit. A dynamical analysis indicates that the proposed
two-planet system is stable over long timescales.Comment: Accepted for publication in A&
DNA damage induced p53 downregulates Cdc20 by direct binding to its promoter causing chromatin remodeling
CDC20 is a critical molecule in the Spindle Assembly Checkpoint (SAC). It activates the Anaphase promoting complex and helps a dividing cell to proceed towards Anaphase. CDC20 is overexpressed in many tumor cells which cause chromosomal instability. There have been limited reports on the mechanism of SAC's response to genotoxic stress. We show that ectopically expressed p53 or DNA damage induced endogenous p53 can downregulate Cdc20 transcriptionally. We have identified a consensus p53-binding site on the Cdc20 promoter and have shown that it is being used by p53 to bind the promoter and bring about chromatin remodeling thereby repressing Cdc20. Additionally, p53 also downregulates Cdc20 promoter through CDE/CHR element, but in a p21 independent manner. This CDE/CHR element-mediated downregulation occurs only under p53 overexpressed condition but not in the context of DNA damage. The present results suggest that the two CCAAT elements in the Cdc20 promoter are not used by p53 to downregulate its activity, as reported earlier
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