340 research outputs found
Theory of thermalization in an isolated Bose-Einstein condensate
Thermalization in an isolated oscillating Bose-Einstein condensate in a
disordered trap is investigated. We show Shannon entropy in or
representation is the eligible one to describe the thermalization. Besides, we
show that multiple scattering with the disorder generates more and more
incoherent thermal particles and condensed and thermal particles act as mutual
heat bath that results in the thermalization of the whole system. We also
demonstrate that Loschmidt's paradox can be resolved in the present system
Fluoroquinolone therapy for bloodstream infections caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae
AbstractBackground/PurposeFor extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae infections, carbapenems are recommended as first line therapy, and clinical data on the therapeutic efficacy of fluoroquinolones (FQs) is limited. This study compares the efficacy of FQs and carbapenems for bloodstream infections caused by ESBL-producing Escherichia coli or Klebsiella pneumoniae.MethodsBetween 2008 and 2010, adults with ESBL-producing E. coli or K. pneumoniae bacteremia at two medical centers were reviewed. Adults receiving definitive FQ or carbapenem therapy were compared in a propensity score-matched analysis, and 30-day mortality was the primary endpoint.ResultsA total of 299 patients were eligible. Patients receiving a FQ (n = 24), either ciprofloxacin or levofloxacin, had a lower 30-day mortality rate than those with carbapenem therapy (8.3%, 2/24 vs. 23.3%, 64/275; p = 0.12). Multivariate regression analysis revealed that a critical illness [Pitt bacteremia score â„ 4 points; odds ratio (OR), 7.09; p < 0.001], rapidly fatal underlying disease (OR, 5.73; p < 0.001), and hospital-associated infection (OR, 2.57; p = 0.01) were independently associated with 30-day mortality. By contrast, FQ definitive therapy was a protective factor compared with carbapenems (OR, 0.18; p = 0.04). There were 72 matched cases with carbapenem therapy in a propensity score-matched analysis, and a difference in the 30-day mortality rate of two groups was noted (8.3% vs. 29.2%; p = 0.05).ConslusionFor ESBL-producing E. coli or K. pneumoniae bacteremia, ciprofloxacin or levofloxacin, if active in vitro, can be considered as a carbapenem-sparing alternative
Identifying influential individuals in linkage analysis: Application to a quantitative trait locus detected in the COGA data
Once linkage is detected to a quantitative trait locus (QTL), the next step towards localizing the gene involved may be to identify those families, or individuals, in whom the putative mutations are segregating. In this paper, we describe a jackknife procedure for identifying individuals (and families) who contribute disproportionately to the linkage. Following initial detection of linkage to a QTL, the strategy involves sequentially removing each individual (or each family) from the analysis and recomputing the lod score associated with the linked region using data from all remaining subjects (or families). This procedure can be used to determine if particular observations have substantial impact on evidence for linkage. Identification of such observations may provide insights for further efforts to localize the QTL.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/101831/1/1370170744_ftp.pd
Bacteremic pneumonia caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: Appropriateness of empirical treatment matters
BackgroundClinical information about bacteremic pneumonia caused by extended-spectrum beta-lactamase (ESBL)-producing organism is limited.MethodsA retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2010, clinical information and outcome of adults with bacteremic pneumonia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae were analyzed. The primary outcome is the 30-day mortality.ResultsA total of 111 patients with bacteremic pneumonia caused by E. coli (37 patients, 33.3%) and K. pneumoniae (74, 66.7%) were identified. Their mean age was 69.2 years and 51.4% were male patients. Fifty-seven (51.3%) episodes were classified as hospital-acquired infections, 19 (17.1%) as health-care-associated infections, and four (3.6%) as community-acquired infections. Fifty-one (45.9%) patients received appropriate empiric antimicrobial therapy. The 30-day mortality rate was 40.5% (45 patients). In the multivariate analysis, several independent risk factors, including rapidly fatal underlying disease [odds ratio (OR), 5.75; 95% confidence interval (CI), 1.54â21.48; p = 0.009], severe sepsis (OR, 4.84; 95% CI, 1.55â15.14; p = 0.007), critical illness (OR, 4.28; 95% CI, 1.35â13.57; p = 0.013), and receipt of appropriate empirical therapy (OR, 0.19; 95% CI, 0.07â0.55; p = 0.002), were associated with 30-day mortality. The survival analysis consistently found that individuals with appropriate empiric therapy had a higher survival rate (log-rank test, p < 0.001).ConclusionESBL-producing bacteremic pneumonia, especially health-care-associated infections, often occurred in adults with comorbidities. Appropriate empirical therapy was associated with a favorable outcome
Effect of Porosity Gradient in Gas Diffusion Layer on Cell Performance with Thin-Film Agglomerate Model in Cathode Catalyst Layer of a PEM Fuel Cell
ABSTRACT A one-dimensional, steady-state, two-phase, isothermal numerical simulations were performed to investigate the effect on cell performance of a PEM fuel cell under non-uniform porosity of gas diffusion layer. In the simulation, the non-uniform porosity of gas diffusion layer was taken into account to analyze the transport phenomena of water flooding and mass transport in the gas diffusion layer. The porosity of the gas diffusion layer is treated as a linear function. Furthermore, the structure of the catalyst layer is considered to be a cylindrical thin-film agglomerate. Regarding the distribution analysis of liquid water saturation, oxygen concentration and water concentration depend on the porosity of gas diffusion layer. In the simulation, the Δ CG and Δ GC represent the porosity of the interfaces between the channel and gas diffusion layer and the gas diffusion layer and the catalyst layer, respectively. The simulation results indicate that when the (Δ CG , Δ GC ) = (0.8, 0.4), higher liquid water saturation appears in the gas diffusion layer and the catalyst layer. On the contrary, when the (Δ CG , Δ GC ) = (0.4, 0.4), lower liquid water saturation appears. Once the liquid water produced by the electrochemical reaction and condensate of vapor water may accumulate in the open pores of the gas diffusion layer and reduced the oxygen transport to the catalyst sites. This research attempts to use a thin-film agglomerate model, which analyze the significant transport phenomena of water flooding and mass transport under linear porosity gradient of gas diffusion layer in the cathode of a PEM fuel cell
Identity-by-Descent Mapping Identifies Major Locus for Serum Triglycerides in Amerindians Largely Explained by an APOC3 Founder Mutation
BackgroundâIdentity-by-descent (IBD) mapping using empirical estimates of IBD allele sharing may be useful for studies of complex traits in founder populations, where hidden relationships may augment the inherent genetic information that can be used for localization.
Methods and ResultsâThrough IBD mapping, using ~400,000 SNPs, of serum lipid profiles we identified a major linkage signal for triglycerides (TG) in 1,007 Pima Indians (LOD=9.23, p=3.5Ă10â11 on chromosome 11q). In subsequent fine-mapping and replication association studies in ~7,500 Amerindians, we determined that this signal reflects effects of a loss-of-function Ala43Thr substitution in APOC3 (rs147210663) and 3 established functional SNPs in APOA5. The association with rs147210663 was particularly strong; each copy of the Thr allele conferred 42% lower TG (ÎČ=â0.92±0.059 SD unit, p=9.6Ă10â55 in 4,668 Pimas and 2,793 Southwest Amerindians combined). The Thr allele is extremely rare in most global populations, but has a frequency of 2.5% in Pimas. We further demonstrated that 3 APOA5 SNPs with established functional impact could explain the association with the most well-replicated SNP (rs964184) for TG identified by genome-wide association studies (GWAS). Collectively these 4 SNPs account for 6.9% of variation in TG in Pimas (and 4.1% in Southwest Amerindians), and their inclusion in the original linkage model reduced the linkage signal to virtually null.
ConclusionsâAPOC3/APOA5 constitutes a major locus for serum triglycerides in Amerindians, especially the Pimas, and these results provide an empirical example for the concept that population-based linkage analysis is a useful strategy to identify complex trait variants
Association of CREBRF variants with obesity and diabetes in Pacific Islanders from Guam and Saipan
Aims hypothesis Variants in CREBRF (rs12513649 and rs373863828) have been strongly associated with increased BMI and decreased risk of type 2 diabetes in Polynesian populations; the A allele at rs373863828 is common in Polynesians but rare in most other global populations. The aim of the present study was to assess the association of CREBRF variants with obesity and diabetes in Pacific Islander (largely Marianas and Micronesian) populations from Guam and Saipan. Methods CREBRF rs12513649 and rs373863828 were genotyped in 2022 participants in a community-based cross-sectional study designed to identify determinants of diabetes and end-stage renal disease (ESRD). Associations were analysed with adjustment for age, sex, ESRD and the first four genetic principal components from a genome-wide association study (to account for population stratification); a genomic control procedure was used to account for residual stratification. Results The G allele at rs12513649 had an overall frequency of 7.7%, which varied from 2.2% to 20.7% across different Marianas and Micronesian populations; overall frequency of the A allele at rs373863828 was 4.2% (range: 1.1â5.4%). The G allele at rs12513649 was associated with higher BMI (ÎČ=1.55 kg/m2 per copy; p=0.0026) as was the A allele at rs373863828 (ÎČ=1.48 kg/m2, p=0.033). The same alleles were associated with lower risk of diabetes (OR per copy: 0.63 [p=0.0063] and 0.49 [p=0.0022], respectively). Meta-analyses combining the current results with previous results in Polynesians showed a strong association between the A allele at rs373863828 and BMI (ÎČ=1.38 kg/m2;p=2.5Ăl0â29) and diabetes (OR=0.65, p=1.5Ăl0â13). Conclusions interpretation These results confirm the associations of CREBRF variants with higher BMI and lower risk of diabetes and, importantly, they suggest that these variants contribute to the risk of obesity and diabetes in Oceanic populations
THE EFFECTS AFTER THINNING OF JAPANESE CEDAR AT XITOU
This study sat two experimental plots each for 400m2 ha of 40 years old Japanese cedar (Cryptomeria japonica) plantation at National Taiwan University Experimental Forest Xitou Tract: Control (non-thinning) plot and 40% thinning plot. The original planting density was 2000 trees for each ha of all the experimental plots. After complete enumeration of all the experimental plots, measurements of photosynthesis were taken and multiplied by the total leaf area for each sample tree; then accounting for the number of trees in the forest, the percentage of the forest stand that could get the annual carbon sequestration of forest stand was. The results showed significant correlation between tree dominance and increment (R2>0.7) for non-thinning Japanese cedar, higher and bigger diameter trees showed more growth increment but stagnant for overtopped trees. After thinning, all the low-diameter trees have increase significantly in increment for 30-50%. The photosynthesis ability measured results shown that Japanese cedar photosynthetic efficiency have no significant differences after thinning, but due to the total leaf area growth, so that it could increase carbon sequestration efficiency by 22-38% after thinning
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