The study researched the relationship between vegetation cover and PM pollution. The raster NDVI dataset from 1998 to 2016 were reclassified into low, medium, and high vegetation coverage area, and the corresponding PM concentration in eight economic regions in China were then calculated. On this basis, the temporal and spatial characteristics of PM pollution were analyzed and Pearson correlation coefficient was used to explore its correlation with NDVI landscape pattern indexes separately from landscape and class level NDVI.
View Article and Find Full Text PDFDuring soil formation, the accumulation of humic substances such as humic acid and fulvic acid is an important way to maintain soil fertility and nutrient cycling, which is regulated by soil substrate quality, litter, and environmental factors. In a laboratory incubation experiment, we exa-mined the effects of litter addition on soil humic substances accumulation in freeze-thaw environment by controlling the freeze-thaw cycles and litter additions in soils from the typical coniferous forest, mixed forest and broadleaved forest in a subalpine forest in western Sichuan. The freeze-thaw events significantly increased the content of humic substances in the coniferous forest soils but decreased those in the mixed forest soil and broadleaved forest soil.
View Article and Find Full Text PDFInt J Environ Res Public Health
December 2015
This study investigated the spatial distribution, spatial autocorrelation, temporal cluster, spatial-temporal autocorrelation and probable risk factors of H7N9 outbreaks in humans from March 2013 to December 2014 in China. The results showed that the epidemic spread with significant spatial-temporal autocorrelation. In order to describe the spatial-temporal autocorrelation of H7N9, an improved model was developed by introducing a spatial-temporal factor in this paper.
View Article and Find Full Text PDFTo understand the effects of the lack of snow pack under global warming on the characteristics of soil microorganisms during wintertime, a snow-shading experiment was conducted in a primary fir (Abies faxoniana) forest after snow pack removal, with the soil microbial biomass carbon (MBC) and nitrogen (MBN) and soil culturable microorganisms (bacteria and fungi) at the stages of snow forming, snow covering, and snow melting investigated. Snow pack removal had significant effects on the soil MBC and MBN and the number of soil culturable bacteria and fungi, but the responses of the culturable microorganisms differed with the stages of snow-shading. Under the condition of snow pack removal, the MBC and MBN in soil organic layer decreased significantly at the early stages of snow forming and snow melting but increased significantly at snow covering stage and at the later stage of snow melting, and the number of culturable bacteria decreased significantly from the early stage of snow forming to the stage of snow covering while that of culturable fungi had a significant increase from the early stage of snow forming to the stage of snow melting.
View Article and Find Full Text PDFSeasonal freeze-thaw cycle and its change pattern under the scenarios of climate warming might exert strong effects on the soil nitrogen mineralization in alpine forests. In this paper, intact soil cores were collected from the subalpine/alpine forests along an altitudinal gradient in west Sichuan, and an incubation test was conducted to study the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen in the forests during growth season and seasonal freeze-thaw period under simulated scenarios of global warming. In the test soils, the NH(4+)-N and NO(3-)-N contents both showed a clear tendency of decreased in the period from growth season to the onset stage of freezing, increased at deep freezing stage, and decreased again at the early stage of thawing.
View Article and Find Full Text PDFThe dynamic changes of snow pack as affected by global warming might have strong effects on the ecological processes in alpine forests. To understand the responses of soil ecological processes in the alpine forests of west Sichuan to the decreasing snow pack under global warming, a snow-shading experiment was conducted in a primary fir forest from October 19, 2009 to May 18, 2010, with the effects of snow pack removal on the dynamics of soil temperature, carbon, nitrogen, and phosphorus investigated. The results showed that snow pack removal increased the diurnal variation amplitude of soil temperature and the frequency of freeze-thaw cycle, and advanced the time of soil frozen and melt as well as the peak time of soil dissolved carbon and nitrogen, available P, NH4(+)-N, and NO3(-)-N.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
May 2011
Late soil-thawing period is a critical stage connecting winter and growth season. The significant temperature fluctuation at this stage might have strong effects on soil ecological processes. In order to understand the soil biochemical processes at this stage in the subalpine/alpine forests of west Sichuan, soil samples were collected from the representative forests including primary fir forest, fir and birch mixed forest, and secondary fir forest in March 5-April 25, 2009, with the activities of soil invertase, urease, and phosphatase (neutral, acid and alkaline phosphatases) measured.
View Article and Find Full Text PDFNan Fang Yi Ke Da Xue Xue Bao
January 2011
Objective: To investigate the effect of transplantation of bone-marrow mesenchymal stem cells (MSCs) on the immune functions of aging rats.
Methods: Healthy SD rats were randomized into normal control, aging model group and MSCs group. The aging model was established by daily subcutaneous injection of D-galactose for 4 consecutive months.
Objective: To assess the outcomes of the therapy for patients with refractory leukemia with HLA haploidentical stem cells transplantation.
Methods: To analyze the outcomes of 30 patients with refractory leukemia who underwent HLA haploidentical peripheral blood stem cells transplantation from August 1998 to August 2004.
Results: Thirty refractory leukemia patients including 13 cases of acute non-lymphocytic leukemia, 10 cases of acute lymphocytic leukemia (ALL), 6 cases of chronic myeloid leukemia and 1 case of phase IV non-Hodgkin's lymphoma underwent HLA haploidentical peripheral blood stem cells transplantation.
Background & Objective: The complete remission of refractory leukemia treated with conventional chemotherapy is below 50 percent. The high dose chemotherapy can cause more mortality of patients with refractory leukemia. Cytolysis of leukemia cells induced by halpotype lymphocytes was observed in vitro in our previous experiment.
View Article and Find Full Text PDFZhongguo Shi Yan Xue Ye Xue Za Zhi
June 2003
In order to observe the curative and side effects in malignant hematologic diseases treated with autologous peripheral blood stem cell transplantation (auto-PBSCT) combined with halotype lymphocyte infusion, auto-PBSCs were mobilized, harvested and stored at -196 degrees C from patients in first CR or PR with intensive chemotherapy (Ara-C 1.0 g/m(2) x 5 days or cyclophosphamide 60 mg/kg x 2 days) and G-CSF. Unpurged auto-PBSCs were infused when patients received the conditioning regimen with busulfan, total irradiation or cyclophosphamide.
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