[Effect of Vegetation Coverage on the Temporal and Spatial Distribution of PM2.5 Concentration in China's Eight Major Economic Regions from 1998 to 2016].

The study researched the relationship between vegetation cover and PM2.5 pollution. The raster NDVI dataset from 1998 to 2016 were reclassified into low, medium, and high vegetation coverage area, and the corresponding PM2.5 concentration in eight economic regions in China were then calculated. On this basis, the temporal and spatial characteristics of PM2.5 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. The preliminary results showed that:①The northern, eastern, southern coastal, middle reaches of the Yangtze River, and the northeast economic zones have relatively low vegetation coverage in areas with relatively serious PM2.5 pollution. However, the middle reaches of the Yellow River, the southwestern and the Northwestern Economic Zones in areas with relatively low vegetation coverage showed lighter PM2.5 pollution. ②PM2.5 increased in most areas between 1998 and 2016. ③A significant correlation between PM2.5 and NDVI landscape pattern indexes was not found for all areas. ④Therefore, the impacts of the landscape shape index(LSI), percent of landscape(PLAND), number of patches(NP), largest patch index(LPI), and aggregation index(AI) on PM2.5 are heterogeneous.

[Effects of litter addition on the dynamics of soil humic substances during freeze-thaw events in a subalpine forest.] / å†»èžçŽ¯å¢ƒä¸‹äºšé«˜å±±æ£®æž—å‡‹è½å¶æ·»åŠ å¯¹åœŸå£¤è æ®–è´¨åŠ¨æ€çš„å½±å“.

During 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. Litter addition had no significant effect on the content of soil humic substances. Freeze-thaw events increased the content of humic acid, with the net accumulation of humic acid following the order of mixed forest > coniferous forest > broad-leaved forest. Freeze-thaw events decreased the content of fulvic acid in the three forest soils during the early stage of incubation, and the degree of fulvic acid degradation was broadleaved forest > mixed forest > coniferous forest. Litter addition had no significant effect on the content of soil humic acid and fulvic acid. With prolonged incubation, the content of humic acid and fulvic acid in the three types of forest soils all declined. These results indicated that litter had effects on soil humic substances, which were related to soil substrate quality and affected by the duration of soil freeze-thaw events in winter.

A Predictive Risk Model for A(H7N9) Human Infections Based on Spatial-Temporal Autocorrelation and Risk Factors: China, 2013-2014.

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. Logistic regression analyses were utilized to investigate the risk factors associated with their distribution, and nine risk factors were significantly associated with the occurrence of A(H7N9) human infections: the spatial-temporal factor φ (OR = 2546669.382, p < 0.001), migration route (OR = 0.993, p < 0.01), river (OR = 0.861, p < 0.001), lake(OR = 0.992, p < 0.001), road (OR = 0.906, p < 0.001), railway (OR = 0.980, p < 0.001), temperature (OR = 1.170, p < 0.01), precipitation (OR = 0.615, p < 0.001) and relative humidity (OR = 1.337, p < 0.001). The improved model obtained a better prediction performance and a higher fitting accuracy than the traditional model: in the improved model 90.1% (91/101) of the cases during February 2014 occurred in the high risk areas (the predictive risk > 0.70) of the predictive risk map, whereas 44.6% (45/101) of which overlaid on the high risk areas (the predictive risk > 0.70) for the traditional model, and the fitting accuracy of the improved model was 91.6% which was superior to the traditional model (86.1%). The predictive risk map generated based on the improved model revealed that the east and southeast of China were the high risk areas of A(H7N9) human infections in February 2014. These results provided baseline data for the control and prevention of future human infections.

[Effects of snow pack removal on soil microbial biomass carbon and nitrogen and the number of soil culturable microorganisms during wintertime in alpine Abies faxoniana forest of western Sichuan, Southwest China].

To 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. After snow melting, the MBC and the number of culturable fungi in soil organic layer had a significant decrease, the number of cultural bacteria was in adverse, but the MBN had less change. The MBC and MBN and the number of culturable microorganisms in soil mineral layer had the similar variation trends as those in soil organic layer, but the fluctuations were smaller. It was suggested that snow pack removal changed the ratio of culturable bacteria to culturable fungi, showing positive effects on the number of soil culturable fungi during wintertime in alpine Abies faxoniana forest of western Sichuan.

[Characteristics of soil net nitrogen mineralization in subalpine/alpine forests of west Sichuan, Southwest China during seasonal freeze-thaw period].

Seasonal 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. The soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen were significantly lower in freeze-thaw period than in growth season, and the soil inorganic nitrogen was obviously immobilized. The soil nitrogen immobilization was stronger at middle altitudes but weaker at high altitudes, as compared with that at low altitudes, possibly due to the variation of soil temperature and its induced different freeze-thaw cycle. During growth period, the soil net nitrogen mineralization rate and the amount of soil mineralized nitrogen showed an obvious increasing trend with the decrease of altitude, and the soil nitrogen mineralization was the strongest at low altitudes, implying that under the scenarios of climate warming, the increase of soil temperature promoted the soil nitrogen mineralization during growth season, and affected the soil nitrogen mineralization rate by increasing the frequency of freeze-thaw cycle and shortening the time period of freeze-thaw. Soil micro-environment could also affect the soil nitrogen mineralization in alpine forest regions.

[Soil hydrolase characteristics in late soil-thawing period in subalpine/alpine forests of west Sichuan].

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. In soil frozen period, the activities of the three enzymes in test forests still kept relatively higher. With the increase of soil temperature, the activities of hydrolases at the early stage of soil-thawing decreased rapidly after a sharp increase, except for neutral phosphatease. Thereafter, there was an increase in the activities of urease and phosphatase. Relative to soil mineral layer, soil organic layer had higher hydrolase activity in late soil-thawing period, and showed more obvious responses to the variation of soil temperature.

[Effect of bone-marrow mesenchymal stem cells on the immune function of aging rats].

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. MSCs were isolated from the bone marrow of adult SD rats and injected (3×10(6) MSCs) in rats in the MSCs group via the tail vein once a week for 4 weeks. The spleen index, activity of T lymphocytes and the levels of IL-2 and IL-10 in spleen were measured, and the pathological changes of the spleen were observed after the treatments. RESULTS: MSCs transplantation enhanced the cellular immune function of aging rats manifested by obviously increased spleen index, activity of T lymphocyte and the level of IL-2, and lowered level of IL-10 in the spleen. The rats in the aging model group showed serious spleen injury, which was obviously lessened by MSCs injection. CONCLUSION: MSCs transplantation can improve the cellular immune function of aging rats and ameliorate spleen injury induced by D-galactose.

[Effects of snow pack removal on the dynamics of winter-time soil temperature, carbon, nitrogen, and phosphorus in alpine forests of west Sichuan].

The 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. Snow pack removal increased the concentrations of soil dissolved carbon and nitrogen and NO3(-)-N but decreased the concentrations of soil available P and NH4(+)-N, and changed the ratios of soil dissolved carbon and nitrogen, available P, NH4(+)-N, and NO3(-)-N in the period of snow cover and snow melt. The decreased snow pack in winter time in the alpine forests of west Sichuan as affected by global warming could alter the soil exterior environment, and further, affect the processes of soil carbon, nitrogen and phosphorus.

[The outcomes of the thirty patients with refractory leukemia treated with related HLA haploidentical stem cells transplantation].

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. The median age was 25 years old (3-52 years old). Twelve patients received stem cells from parent donors, four from daughter or son donors and the remaining from sibling donors. Three HLA loci mismatched in twelve cases, two HLA loci mismatched in thirteen cases and one HLA locus mismatched in five cases. The conditioning regime consisted of fludara (25 mg/m(2) x 5 d), busulfan (4 mg/kg x 4 d) and cyclophosphamide (60 mg/kg x 2 d). Rabbit anti-human lymphocyte globulin (5 mg/kg x 5 d) was added in some patients in the conditioning regime. A mean of 5.0 (2.9-8.0) x 10(8)/kg mononucleated cells was grafted. The number of mean CD(34)(+) cells was 5.5 (3.0-6.5) x 10(6)/kg. Twenty-seven patients were successfully grafted, one failed to graft, one died from severe fungal infection at day 2 and one died from severe veno-occlusive disease at day 28. The mean time of white cell count more than 1.0 x 10(9)/L was 14 (11-18) days and platelet count more than 20 x 10(9)/L was 15 (11-18) days. ALL the 27 successfully grafted patients got complete remission. Severe acute graft versus host disease occurred in six patients and four of them died. Seven patients suffered from chronic graft versus host disease. Seven patients relapsed and died. The median relapse time was 10 (3-24) months. Fourteen patients are still surviving, and ten have disease free survival. CONCLUSION: It is concluded from our observation that HLA haploidentical peripheral blood stem cells transplantation may be an effective therapy for refractory and relapse leukemia. Some patients with refractory and relapse leukemia treated with HLA haploidentical stem cells transplantation may have disease free survival. Graft versus leukemia effect may be strong in patients receiving HLA haploidentical blood stem cells transplantation and leukemia will probably be relapsed when the patient without complete remission was treated with this therapy.

[Treatment of refractory leukemia by combined chemotherapy and halpotype lymphocytes infusion].

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. In order to improve the complete remission of refractory leukemia and decrease the complication of chemotherapy,the authors treated the patients with refractory leukemia by combined chemotherapy and halpotype lymphocytes infusion and to assess the therapeutic effects and the side effects of this modality. METHODS: Sixteen patients with refractory leukemia were treated by combined chemotherapy. Halpotype lymphocytes irradiated by 7.5 Gygamma radial were infused when patient's white cells count was at the lowest after the chemotherapy. A mean number of 1x10(8)/kg (range:0.8-1.2x10(8)/kg) of halpotype lymphocytes irradiated by 7.5 Gygamma radial was infused. The side effects of infusion of halpotype lymphocyte and completed remission rate were observed. RESULTS: Out of thirteen patients with refractory acute non-lymphocyte leukemia, eleven cases got complete remission and two partial remissions. Out of three patients with refractory acute lymphocyte leukemia, two got complete remission and one no reaction. The total remission rate was 81.2%. No severe side effects and no transfusion related graft versus host disease was observed. CONCLUSION: The results show that chemotherapy combined with 7.5 Gy irradiated halpotype lymphocyte infusion could improve the complete remission of refractory leukemia and decrease the complications caused by chemotherapy.

[Treatment of malignant hematologic diseases by peripheral blood stem cell transplantation combined with halotype lymphocyte infusion].

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. Halotype lymphocytes [mean 5.0 x 10(7)/kg, (4.5 - 6.5) x 10(7)/kg] irradiated with 7.5 Gy were infused to patients when WBCs were more than 1 x 10(9)/L. Hematopoietic recovery and survival of patients were observed. The results showed that in 12 cases accepted this protocol, five patients with acute non-lymphocytic leukemia got to durable remission, of which 2 had durable remission of more than 50 months. One of three patients with non-Hodgkin's lymphoma IVb reached durable remission, and two relapsed and died on 4 and 6 months after treatment, respectively. Two CML patients were also achieved durable remission. One patient with multiple myeloma relapsed on 36 months later, but he still survived disease-free with treatment of thalidomide. In a follow-up survey of 25 months, the disease-free survival was 83%. No severe side effects were observed except platelet delayed recovery after halotype lymphocyte infusion. STR-PCR analysis showed that infused donor lymphocytes disappeared in 3 recipients at 72 hours after infusion. It is concluded that auto-PBSCT combined with halotype lymphocyte infusion could decrease the relapse of malignant hematologic diseases and improve the effect of auto-PBSCT. Recovery of platelet, however, could be delayed by halotype lymphocyte infusion.