366 research outputs found

    The Okhotsk-Japan Circulation Pattern and the Heavy Rainfall in Beijing in 2012 Summer

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    Using station precipitation and reanalysis data, we examined the evolution of the large-scale circulations associated with the heavy rainfall event that occurred around July 21, 2012 (721 heavy rainfall). This study focuses on a role that the large-scale circulations named ā€œthe Okhotsk-Japan (OKJ) circulation patternā€ played in causing the heavy rainfall case. We found that the 721 heavy rainfall occurred under a background of the OKJ circulation that persisted for about 10 days. However, the pattern was different from the normal OKJ circulation, for this circulation pattern accompanied a blocking high between the Ural Mountains and the Baikal Lake. This difference resulted from the seasonal change of the basic flow. The related Rossby wave propagated eastward during the persisting period of the dominated OKJ pattern. This caused the development of a low-pressure system around the Baikal Lake and the weakening of a ridge around the Okhotsk Sea. The slow evolution of the OKJ circulation created a favorable environment for the moisture transport to northern China, assisting in the generation of the 721 heavy rainfall

    Competition Effect in Atomic-Molecular System

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    The competition effects among the processes of atomic ionization, optical pumped stimulated radiation (OPSR), four-wave frequency mixing (FWFM) and molecular stimulated diffuse band radiation at the atomic two-photon resonance of 3S approaches 4D in Na2 - Na mixture were observed. The dip at the two-photon resonance in the excitation spectrum for the diffuse-band radiation was interpreted as suppression of population in 4D state

    Characterization of Chemical Composition of Pericarpium Citri Reticulatae Volatile Oil by Comprehensive Two-Dimensional Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry

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    Pericarpium Citri Reticulatae (Chenpi in Chinese) has been widely used as an herbal medicine in Korea, China, and Japan. Chenpi extracts are used to treat indigestion and inflammatory syndromes of the respiratory tract such as bronchitis and asthma. This thesis will analyze chemical compositions of Chenpi volatile oil, which was performed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC Ɨ GC-HR-TOFMS). One hundred and sixty-seven components were tentatively identified, and terpene compounds are the main components of Chenpi volatile oil, a significant larger number than in previous studies. The majority of the eluted compounds, which were identified, were well separated as a result of high-resolution capability of the GC Ɨ GC method, which significantly reduces, the coelution. Ī²-Elemene is tentatively qualified by means of GC Ɨ GC in tandem with high-resolution TOFMS detection, which plays an important role in enhancing the effects of many anticancer drugs and in reducing the side effects of chemotherapy. This study suggests that GC Ɨ GC-HR-TOFMS is suitable for routine characterization of chemical composition of volatile oil in herbal medicines

    Earthworms accelerate rice straw decomposition and maintenance of soil organic carbon dynamics in rice agroecosystems

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    Background To promote straw degradation, we inoculated returned farmland straw with earthworms (Pheretima guillelmi). Increasing the number of earthworms may generally alter soil organic carbon (SOC) dynamics and the biological activity of agricultural soils. Methods We performed soil mesocosm experiments with and without earthworms to assess the decomposition and microbial mineralization of returned straw and soil enzyme activity across different time periods. Results When earthworms were present in soil, the surface residues were completely consumed during the first four weeks, but when earthworms were absent, most of the residues remained on the soil surface after 18 weeks. On day 28, the SOC content was significantly higher in the treatment where both earthworms and residue had been added. The SOC content was lower in the treatment where earthworms but no residue had been added. The organic carbon content in water-stable macroaggregates showed the same trend. During the first 14 weeks, the soil basal respiration was highest in the treatments with both residues and earthworms. From weeks 14 to 18, basal respiration was highest in the treatments with residues but without earthworms. We found a significant positive correlation between soil basal respiration and soil dissolved organic carbon content. Earthworms increased the activity of protease, invertase, urease and alkaline phosphatase enzymes, but decreased Ī²-cellobiohydrolase, Ī²-glucosidase and xylosidase activity, as well as significantly reducing ergosterol content. Conclusion The primary decomposition of exogenous rice residues was mainly performed by earthworms. Over a short period of time, they converted plant carbon into soil carbon and increased SOC. The earthworms played a key role in carbon conversion and stabilization. In the absence of exogenous residues, earthworm activity accelerated the decomposition of original organic carbon in the soil, reduced SOC, and promoted carbon mineralization

    High Incidence and Endemic Spread of NDM-1-Positive Enterobacteriaceae in Henan Province, China

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    The emergence and spread of New Delhi metallo-Ī²-lactamase 1 (NDM-1)-producing carbapenem-resistant Enterobacteriaceae (CRE) present an urgent threat to human health. In China, the blaNDM-1 gene has been reported mostly in Acinetobacter spp. but is rarely found in Enterobacteriaceae. Here, we report a high incidence and endemic spread of NDM-1-producing CRE in Henan Province in China. Sixteen (33.3%) of the 48 CRE isolates obtained from patients during June 2011 to July 2012 were positive for blaNDM-1, and the gene was found to be carried on plasmids of various sizes (āˆ¼55 to āˆ¼360 kb). These plasmids were readily transferrable to recipient Escherichia coli by conjugation, conferred resistance to multiple antibiotics, and belonged to multiple replicon types. The blaNDM-1-positive CRE isolates were genetically diverse, and six new multilocus sequence typing (MLST) sequence types were linked to the carriage of NDM-1. Five of the isolates were classified as extensively drug-resistant (XDR) isolates, four of which also carried the fosA3 gene conferring resistance to fosfomycin, an alternative drug for treating infections by CRE. In each blaNDM-1-positive CRE isolate, the blaNDM-1 gene was downstream of an intact ISAba125 element and upstream of the bleMBL gene. Furthermore, gene environment analysis suggested the possible transmission of blaNDM-1-containing sequences from Acinetobacter spp. to Klebsiella pneumoniae and Klebsiella oxytoca. These findings reveal the emergence and active transmission of NDM-1-positive CRE in China and underscore the need for heightened measures to control their further spread

    First identification of NDM-4-producing Escherichia coli ST410 in China

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    Dear Editor, The worldwide dissemination of New Delhi metallo-Ī²-lactamase 1 (NDM-1), an Ambler class B metallo-Ī²-lactamase (MBL) conferring resistance to all Ī²-lactams except monobactams, is of great concern for public health. NDM-4, which differs from NDM-1 by a single amino acid substitution (Met154Leu), was demonstrated to possess increased carbapenemase activity

    Integrated gene-based and pathway analyses using UK Biobank data identify novel genes for chronic respiratory diseases

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    BackgroundChronic respiratory diseases have become a non-negligible cause of death globally. Although smoking and environmental exposures are primary risk factors for chronic respiratory diseases, genetic factors also play an important role in determining individualā€™s susceptibility to diseases. Here we performed integrated gene-based and pathway analyses to systematically illuminate the heritable characteristics of chronic respiratory diseases.MethodsUK (United Kingdom) Biobank is a very large, population-based prospective study with over 500,000 participants, established to allow detailed investigations of the genetic and nongenetic determinants of the diseases. Utilizing the GWAS-summarized data downloaded from UK Biobank, we conducted gene-based analysis to obtain associations of susceptibility genes with asthma, chronic obstructive pulmonary disease (COPD) and pneumonia using FUSION and MAGMA software. Across the identified susceptibility regions, functional annotation integrating multiple functional data sources was performed to explore potential regulatory mechanisms with INQUISIT algorithm. To further detect the biological process involved in the development of chronic respiratory diseases, we undertook pathway enrichment analysis with the R package (clusterProfiler).ResultsA total of 195 susceptibility genes were identified significantly associated with chronic respiratory diseases (Pbonferroni < 0.05), and 24/195 located out of known susceptibility regions (e.g. WDPCP in 2p15). Within the identified susceptibility regions, functional annotation revealed an aggregation of credible variants in promoter-like and enhancer-like histone modification regions and such regulatory mechanisms were specific to lung tissues. Furthermore, 110 genes with INQUISIT score ā‰„1 may influence diseases susceptibility through exerting effects on coding sequences, proximal promoter and distal enhancer regulations. Pathway enrichment results showed that these genes were enriched in immune-related processes and nicotinic acetylcholine receptors pathways.ConclusionsThis study implemented an integrated gene-based and pathway strategy to explore the underlying biological mechanisms and our findings may serve as promising targets for future clinical treatments of chronic respiratory diseases

    Acute exposure to fine particulate matter and cardiovascular hospital emergency room visits in Beijing, China

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    Fine particulate matter (PM2.5) air pollution outbreaks have recently occurred frequently in China. However, evidence of the associations between short-term exposure to PM2.5 and cardiovascular morbidity is still limited in China. This study aimed to evaluate the associations between PM2.5 and hospital emergency room visits (ERVs) for cardiovascular diseases in urban areas in Beijing. Daily counts of cardiovascular ERVs were collected from ten large general hospitals from Jan 1 to Dec 31, 2013. Air pollution data were obtained from the Beijing Environmental Protection Bureau including 17 monitoring stations. A generalized additive Poisson model was used to examine the associations between PM2.5 and cardiovascular ERVs after controlling for seasonality, day of the week, public holidays, influenza outbreaks, and weather conditions. In total, there were 56,221 cardiovascular ERVs during the study period. The daily mean PM2.5 concentration was 102.1 Ī¼g/m3, ranging from 6.7 Ī¼g/m3 to 508.5 Ī¼g/m3. Per 10 Ī¼g/m3 increase in PM2.5 was associated with a 0.14% (95% confidence interval [CI]: 0.01%ā€“0.27%) increase in cardiovascular ERVs at lag3. Cumulative delayed estimates were greatest at lag0ā€“5 (0.30%, 95% CI: 0.09%ā€“0.52%). The estimates of percentage change in daily ERVs per 10 Ī¼g/m3 increase in PM2.5 were 0.56% (95%CI: 0.16%ā€“0.95%) for ischemic heart disease (IHD) at lag0ā€“1, 0.81% (95%CI: 0.05%ā€“1.57%) for heart rhythm disturbances (HRD) at lag0ā€“1 and 1.21% (95%CI: 0.27%ā€“2.15%) for heart failure (HF) at lag0, respectively. The effects of PM2.5 on IHD ERVs during high temperature days (\u3e11.01 Ā°C) were significantly higher than that on low temperature days (ā‰¤11.01 Ā°C) at lag0, lag0ā€“1, lag0ā€“3 and lag0ā€“5 (P \u3c 0.05). The study suggests that PM2.5 has acute impacts on cardiovascular ERVs in Beijing, especially on IHD, HRD and HF. The effects of PM2.5 on IHD ERVs vary by temperature

    Theory and Experiments of Pressure-Tunable Broadband Light Emission from Self-Trapped Excitons in Metal Halide Crystals

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    Hydrostatic pressure has been commonly applied to tune broadband light emissions from self-trapped excitons (STE) in perovskites for producing white light and study of basic electron-phonon interactions. However, a general theory is still lacking to understand pressure-driven evolution of STE emissions. In this work we first identify a theoretical model that predicts the effect of hydrostatic pressure on STE emission spectrum, we then report the observation of extremely broadband photoluminescence emission and its wide pressure spectral tuning in 2D indirect bandgap CsPb2Br5 crystals. An excellent agreement is found between the theory and experiment on the peculiar experimental observation of STE emission with a nearly constant spectral bandwidth but linearly increasing energy with pressure below 2 GPa. Further analysis by the theory and experiment under higher pressure reveals that two types of STE are involved and respond differently to external pressure. We subsequently survey published STE emissions and discovered that most of them show a spectral blue-shift under pressure, as predicted by the theory. The identification of an appropriate theoretical model and its application to STE emission through the coordinate configuration diagram paves the way for engineering the STE emission and basic understanding of electron-phonon interaction
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