311 research outputs found

    Variation of the Atmospheric Boundary Layer Height at the Eastern Edge of the Tibetan Plateau

    Full text link
    This paper utilized the high temporal and spatial resolution temperature profile data observed by the multi-channel microwave radiometer at the Large High Altitude Air Shower Observatory (LHAASO) on the eastern slope of the Tibetan Plateau from February to May and August to November 2021, combined with the ERA5 reanalysis data products for the whole year of 2021, to study the daily, monthly, and seasonal variations of the atmospheric boundary layer height (ABLH). The results are as follows: (1) The ABLH on sunny days showed obvious fluctuations with peaks and valleys. The ABLH continued to rise with the increase of surface temperature after sunrise and usually reached its maximum value in the afternoon around 18:00, then rapidly decreased until sunset. (2) The average ABLH in April was the highest at about 1200 m, while it was only around 600 m in November. The ABLH fluctuated greatly during the day and was stable at around 400 m at night. The ABLH results obtained from ERA5 were slightly smaller overall but had a consistent trend of change with the microwave radiometer. (3) The maximum ABLH appeared in spring, followed by summer and autumn, and winter had the lowest value, with all peaks reached around 14:00-15:00. These results are of great significance for understanding the ABLH on the eastern slope of the Tibetan Plateau, and provide reference for the absolute calibration of photon numbers of the LHAASO telescope and the atmospheric monitoring plan, as well as for evaluating the authenticity and accuracy of existing reanalysis datasets

    Morphologies and elemental compositions of local biomass burning particles at urban and glacier sites in southeastern Tibetan Plateau: Results from an expedition in 2010

    Get PDF
    Many studies indicate that the atmospheric environment over the southern part of the Tibetan Plateau is influenced by aged biomass burning particles that are transported over long distances from South Asia. However, our knowledge of the particles emitted locally (within the plateau region) is poor. We collected aerosol particles at four urban sites and one remote glacier site during a scientific expedition to the southeastern Tibetan Plateau in spring 2010. Weather and backward trajectory analyses indicated that the particles we collected were more likely dominated by particles emitted within the plateau. The particles were examined using an electron microscope and identified according to their sizes, shapes and elemental compositions. At three urban sites where the anthropogenic particles were produced mainly by the burning of firewood, soot aggregates were in the majority and made up >40% of the particles by number. At Lhasa, the largest city on the Tibetan Plateau, tar balls and mineral particles were also frequently observed because of the use of coal and natural gas, in addition to biofuel. In contrast, at the glacier site, large numbers of chain-like soot aggregates (similar to 25% by number) were noted. The morphologies of these aggregates were similar to those of freshly emitted ones at the urban sites: moreover, physically or chemically processed ageing was rarely confirmed. These limited observations suggest that the biomass burning particles age slowly in the cold, dry plateau air. Anthropogenic particles emitted locally within the elevated plateau region may thus affect the environment within glaciated areas in Tibet differently than anthropogenic particles transported from South Asia. (C) 2018 Elsevier B.V. All rights reserved

    Application of ozone ultrafine bubble water for cleaning and sterilizing the dialysis circuit

    Get PDF
    The dialysis circuit was washed by the ultrafine bubble (UFB) water and ozone UFB water and sodium hypochlorite aqueous solution. The effect of washing time, ozone concentration of UFB water, influence of UFB water on artificial dialysis equipment, etc. were investigated. The cleaning and sterilizing effect of ozone UFB water passed through the filter for artificial dialysis was verified. It was confirmed that there were no colony bacteria in the circuit which was washed by the ozone UFB water for 1 hour. Ozone UFB water has the same bactericidal effect as sodium hypochlorite. As an alternative of sodium hypochlorite, we are expecting its application to the cleaning and sterilization of ozone UFB water for dialysis circuit

    Beneficial Effect of Brewers' Yeast Extract on Daily Activity in a Murine Model of Chronic Fatigue Syndrome

    Get PDF
    The aim of this study was to assess the effect of Brewers' yeast extract (BYE) on daily activity in a mouse model of chronic fatigue syndrome (CFS). CFS was induced by repeated injection of Brucella abortus (BA) antigen every 2 weeks. BYE was orally administered to mice in a dose of 2 g per kg per day for 2 weeks before injecting BA and for 4 weeks thereafter. We evaluated daily running activity in mice receiving BYE as compared with that in untreated mice. Weekly variation of body weight (BW) and survival in both groups was monitored during the observation period. Spleen weight (SW), SW/BW ratio, percent splenic follicular area and expression levels of interferon-γ (IFN-γ) and interleukin-10 (IL-10) mRNA in spleen were determined in both groups at the time of sacrifice. The daily activity during 2 weeks after the second BA injection was significantly higher in the treated group than in the control. There was no difference in BW between both groups through the experimental course. Two mice in the control died 2 and 7 days after the second injection, whereas no mice in the treated group died. Significantly decreased SW and SW/BW ratio were observed in the treated mice together with elevation of splenic follicular area. There were suppressed IFN-γ and IL-10 mRNA levels in spleens from the treated mice. Our results suggest that BYE might have a protective effect on the marked reduction in activity following repeated BA injection via normalization of host immune responses

    Characterization of isoprene-derived secondary organic aerosols at a rural site in North China Plain with implications for anthropogenic pollution effects

    Get PDF
    Isoprene is the most abundant non-methane volatile organic compound (VOC) and the largest contributor to secondary organic aerosol (SOA) burden on a global scale. In order to examine the influence of high concentrations of anthropogenic pollutants on isoprene-derived SOA (SOA(i)) formation, summertime PM2.5 filter samples were collected with a three-hour sampling interval at a rural site in the North China Plain (NCP), and determined for SOA(i) tracers and other chemical species. RO2+NO pathway derived 2-methylglyceric acid presented a relatively higher contribution to the SOA, due to the high-NOx (similar to 20 ppb) conditions in the NCP that suppressed the reactive uptake of RO2+HO2 reaction derived isoprene epoxydiols. Compared to particle acidity and water content, sulfate plays a dominant role in the heterogeneous formation process of SOA(i). Diurnal variation and correlation of 2-methyltetrols with ozone suggested an important effect of isoprene ozonolysis on SOA(i) formation. SOA(i) increased linearly with levoglucosan during June 10-18, which can be attributed to an increasing emission of isoprene caused by the field burning of wheat straw and a favorable aqueous SOA formation during the aging process of the biomass burning plume. Our results suggested that isoprene oxidation is highly influenced by intensive anthropogenic activities in the NCP

    Effect of Hochu-ekki-to (TJ-41), a Japanese Herbal Medicine, on Daily Activity in a Murine Model of Chronic Fatigue Syndrome

    Get PDF
    We aimed to evaluate the effect of a Japanese herbal medicine, Hochu-ekki-to (TJ-41), on daily activity in a murine model of chronic fatigue syndrome (CFS). CFS was induced by repeated injection of Brucella abortus (BA) antigen every 2 weeks. TJ-41 was orally administered to mice in a dose of 500 mg/kg/day for 1 week before injecting BA and for 4 weeks thereafter. We evaluated daily running activity in mice receiving TJ-41 as compared with that in untreated mice. Survival of both mouse groups was also monitored during the observation period. Body weight (BW), spleen weight (SW), SW/ BW ratio and expression levels of interleukin-10 (IL-10) mRNA in spleen were determined in both groups at the time of sacrifice. The daily activity was significantly higher in the treated group than in the control. Two mice in the untreated group died 2 days after the second injection of BA, whereas no mice in the group treated with TJ-41 died. The SW and SW/BW ratio were significantly lower in the treated mice than in the control. Suppressed IL-10 mRNA levels were observed in the spleens of the mice treated with TJ-41. Our data suggest that Hochu-ekki-to might possess an inhibitory effect on the marked decrease in running activity following BA injection

    Polarization characteristics of phase retardation defect mode lasing in polymeric cholesteric liquid crystals

    Get PDF
    We have studied the lasing characteristics of a dye-doped nematic layer sandwiched by two polymeric cholesteric liquid crystal (CLC) films as photonic band gap (PBG) materials. The nematic layer acts as a defect layer, the anisotropy of which brings about the following remarkable optical characteristics: (1) reflectance in the PBG region exceeds 50% due to the retardation effect, being unpredictable from a single CLC film; (2) efficient lasing occurs either at the defect mode wavelength or at the photonic band edge; and (3) the lasing emission due to both the defect mode and the photonic band edge mode contains both right- and left-circular polarizations, while the lasing emission from a dye-doped single CLC layer with a left-handed helix is left-circularly polarized.open2

    Chemical characterization of PM2.5 from a southern coastal city of China:applications of modeling and chemical tracers in demonstrationof regional transport

    Get PDF
    An intensive sampling campaign of airborne fine particles (PM2.5) was conducted at Sanya, a coastal city in Southern China, from January to February 2012. Chemical analyses and mass reconstruction were used identify potential pollution sources and investigate atmospheric reaction mechanisms. A thermodynamic model indicated that low ammonia and high relative humidity caused the aerosols be acidic and that drove heterogeneous reactions which led to the formation of secondary inorganic aerosol. Relationships among neutralization ratios, free acidity, and air-mass trajectories suggest that the atmosphere at Sanya was impacted by both local and regional emissions. Three major transport pathways were identified, and flow from the northeast (from South China) typically brought the most polluted air to Sanya. A case study confirmed strong impact from South China (e.g., Pearl River Delta region) (contributed 76.8% to EC, and then this result can be extended to primary pollutants) when the northeast winds were dominant. The Weather Research Forecasting Black carbon model and trace organic markers were used to apportion local pollution versus regional contributions. Results of the study offer new insights into the atmospheric conditions and air pollution at this coastal city

    Mao-to Prolongs the Survival of and Reduces TNF-α Expression in Mice with Viral Myocarditis

    Get PDF
    Goal of this study was to evaluate effects of Mao-to on development of myocarditis induced by encephalomyocarditis (EMC) virus in mice. Mice were randomly divided into five groups. Group N included uninfected controls (n = 18), while group A, B and C underwent intraperitoneal injection of EMC virus. Group A was administered oral saline from day 0 to day 4. Group B was administered oral Mao-to (500 mg−1 kg−1 day−1) from day 0 to day 4. Group C was administered Mao-to from day 2 to day 6. Group D was administered Mao-to from day 5 to day 10. Treated mice were followed for survival rates during 2 weeks after infection. Body weight (BW) and organ weights including heart (HW), lungs, thymus and spleen were examined on days 4, 6 and 14. Survival rate of group C (36.4%) was significantly improved compared with group A, B or D (0% of each, P < 0.05). HW and HW/BW ratio in group C was significantly (P < 0.05) lower than those in group A, B or D. Viral titers of hearts were significantly different among groups A, B and C. Cardiac expression in tumor necrosis factor-α (TNF-α) was significantly reduced in group C in comparison with group A, B or D on day 6 by immunohistochemical study. Administration of Mao-to starting on day 2 improves mortality resulting from viral myocarditis in mice with reduced expression of cardiac TNF-α. These findings suggest that timing of Mao-to is crucial for preventing cardiac damage in mice with viral myocarditis
    corecore