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71.

Background

There is limited evidence for the impacts of meteorological changes on asthma hospital admissions in adults in Shanghai, China.

Objectives

To quantitatively evaluate the short-term effects of daily mean temperature on asthma hospital admissions.

Methods

Daily hospital admissions for asthma and daily mean temperatures between January 2005 and December 2012 were analyzed. After controlling for secular and seasonal trends, weather, air pollution and other confounding factors, a Poisson generalized additive model (GAM) combined with a distributed lag non-linear model were used to explore the associations between temperature and hospital admissions for asthma.

Results

During the study periods, there were 15,678 hospital admissions for asthma by residents of Shanghai, an average 5.6 per day. Pearson correlation analysis found a significant negative correlation (r = −0.174, P<0.001) between asthma hospitalizations and daily mean temperature (DMT). The DMT effect on asthma increased below the median DMT, with lower temperatures associated with a higher risk of hospital admission for asthma. Generally, the cold effect appeared to be relatively acute, with duration lasting several weeks, while the hot effect was short-term. The relative risk of asthma hospital admissions associated with cold temperature (the 25th percentile of temperature relative to the median temperature) was 1.20 (95% confidence interval [CI], 1.01∼1.41) at lag0-14. However, warmer temperatures were not associated with asthma hospital admissions.

Conclusions

Cold temperatures may trigger asthmatic attacks. Effective strategies are needed to protect populations at risk from the effects of cold.  相似文献   
72.
Bulk heterojunction (BHJ) nonfullerene organic solar cells prepared from sequentially deposited donor and acceptor layers (sq‐BHJ) have recently been shown to be highly efficient, environmentally friendly, and compatible with large area and roll‐to‐roll fabrication. However, the related photophysics at donor‐acceptor interface and the vertical heterogeneity of donor‐acceptor distribution, critical for exciton dissociation and device performance, have been largely unexplored. Herein, steady‐state and time‐resolved optical and electrical techniques are employed to characterize the interfacial trap states. Correlating with the luminescent efficiency of interfacial states and its nonradiative recombination, interfacial trap states are characterized to be about 40% more populated in the sq‐BHJ devices than the as‐cast BHJ (c‐BHJ), which probably limits the device voltage output. Cross‐sectional energy‐dispersive X‐ray spectroscopy and ultraviolet photoemission spectroscopy depth profiling directly visualize the donor–acceptor vertical stratification with a precision of 1–2 nm. From the proposed “needle” model, the high exciton dissociation efficiency is rationalized. This study highlights the promise of sequential deposition to fabricate efficient solar cells, and points toward improving the voltage output and overall device performance via eliminating interfacial trap states.  相似文献   
73.
74.
为研究北柴胡种子内生菌的群落结构与多样性.采用Illumina Miseq高通量测序技术,分别对山西(BC_1)、黑龙江(BC_2)、河北(BC_3)和内蒙古(BC_4)的四个产地(4份)北柴胡种子的16S RNA V3-V4区和ITS1区扩增片段进行测序,并对内生细菌和内生真菌群落结构和多样性进行分析.结果表明,BC...  相似文献   
75.
Chromosome duplication and transmission into daughter cells requires the precisely orchestrated binding and release of cohesin. We found that the Drosophila histone chaperone NAP1 is required for cohesin release and sister chromatid resolution during mitosis. Genome-wide surveys revealed that NAP1 and cohesin co-localize at multiple genomic loci. Proteomic and biochemical analysis established that NAP1 associates with the full cohesin complex, but it also forms a separate complex with the cohesin subunit stromalin (SA). NAP1 binding to cohesin is cell-cycle regulated and increases during G2/M phase. This causes the dissociation of protein phosphatase 2A (PP2A) from cohesin, increased phosphorylation of SA and cohesin removal in early mitosis. PP2A depletion led to a loss of centromeric cohesion. The distinct mitotic phenotypes caused by the loss of either PP2A or NAP1, were both rescued by their concomitant depletion. We conclude that the balanced antagonism between NAP1 and PP2A controls cohesin dissociation during mitosis.  相似文献   
76.
13C-enriched deoxyribonucleosides have been isolated from the DNA of Algal cells grown in an atmosphere of 90% 13C-labelled carbon dioxide. The 13C enriched DNA was quantitatively hydrolysed with DNase I, snake venom phosphodiesterase I and alkaline phosphatase of intestinal mucosa. The resulting deoxyribonucleosides were separated by preparative reversed-phase high pressure liquid chromatography in 60 minutes with detection by ultraviolet absorption at 254 nm. The final products were obtained in milligram quantities in high purity and in high yield. The 1H resonances of the base and sugar protons of these deoxyribonucleosides appear as well resolved multiplets in the 600 MHz NMR spectrum, due to the extensive 1H-13C couplings. Similarly, the 13C resonances of these deoxyribonucleosides appear as multiplets in the 75.5 MHz 13C NMR spectrum, due to 13C-13C couplings. The 1H-13C and 13C-13C coupling constants were also measured and tabulated. The isotopic enrichment of 13C these deoxyribonucleosides was obtained by integration of the 1H and/or 13C NMR spectra. It was found that the enrichment varied from carbon to carbon and species to species in the range of 70-89%, suggesting differential uptake and assimilation of 90% 13CO2 during metabolism pathways. This protocol provides experimentally useful quantities of 13C-enriched deoxyribonucleosides, which may be incorporated into site-specifically labeled oligonucleotides by chemical synthesis.  相似文献   
77.
古人口学研究包含对人口学静态参数和动态参数的研究,本文对江苏兴化蒋庄遗址良渚文化墓地进行了性别、年龄结构的分析和生育水平的估计,后者采用的是用n30+/n5+估算粗出生率的方法。蒋庄人口的性别比是105,属于正常范围。模型拟合研究发现蒋庄人口的死亡年龄结构接近正态分布,这种现象可能与婴幼儿统计漏查、成人年龄鉴定中存在的问题和对"老年"标准的定义有关。通过估算粗出生率并将蒋庄样本和其他新石器时代人骨样本进行粗出生率的对比,发现蒋庄人口的生育水平较高,可能与其环境优渥、文明进步有关。研究还表明,对新方法的尝试和对人骨样本代表性的重视是推动古人口学进步的关键。  相似文献   
78.
Molecular cloning of cDNA coding for human preprourokinase   总被引:2,自引:0,他引:2  
A cDNA library was constructed in pBR322 from 18S to 20S mRNA that was extracted from human kidney cells, fractionated on oligo(dT)-cellulose column and sucrose-density gradient, and confirmed for urokinase production in Xenopus laevis oocytes. The Escherichia coli RR1 transformants were hybridized to synthetic oligonucleotide probe prepared according to the known amino acid sequence, Glu 73 to Glu 77 of human urinary urokinase chain B. The entire cloned cDNA covers a 2250-bp region, wherein the 1293-bp sequence codes for preprourokinase consisting of 431 amino acids, with the first 20 residues being a signal peptide. The 5'-untranslated region is at least 80 bp long and the 3'-untranslated region is longer than 850 bp.  相似文献   
79.
Lu  Beibei  Kan  Caixia  Ke  Shanlin  Xu  Haiying  Ni  Yuan  Wang  Changshun  Shi  Daning 《Plasmonics (Norwell, Mass.)》2017,12(4):1183-1191
Plasmonics - Bimetallic nanoparticles have attracted increasing interest because of their unique optical, electronic, magnetic, and catalytic properties which are different from that of their...  相似文献   
80.

Background  

The Twin-arginine translocation (Tat) system serves to translocate folded proteins, including periplasmic enzymes that bind redox cofactors in bacteria. The Tat system is also a determinant of virulence in some pathogenic bacteria, related to pleiotropic effects including growth, motility, and the secretion of some virulent factors. The contribution of the Tat pathway to Vibrio cholerae has not been explored. Here we investigated the functionality of the Tat system in V. cholerae, the etiologic agent of cholera.  相似文献   
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