Plant Pb Contents in Elevation Zones of the Changbai Mountain National Nature Reserve, China

Typical plants and soils of four elevation zones, mountain tundra （Zone A）, Betula ermanii forest （Zone B）, mountain dark coniferous forest （Zone C）, and mountain coniferous and broad-leaf forest （Zone D）, along the vertical gradient of the northern mountain slope of the Changbai Mountain National Nature Reserve, Jilin Province, China, were sampled to study the relationship between plant and soil Pb, and to compare the Pb levels in typical plant types within the same elevation zone. The Pb contents in the soil and plant samples were measured by using a flame atomic absorption spectrophotometer. The results showed that the average plant Pb contents of the four plant elevation zones were lower than the average worldwide level, except for Zone B. Compared with the average level in China or the average worldwide level, the soil Pb levels of the four plant zones were higher, with Zones D and B having the lowest and highest averages, respectively. Plant Pb levels fluctuated from the upper to the lower zones, in a pattern of low-high-low-high, which was the same as that of the soils in the four zones. Furthermore, plant Pb was closely related to soil Pb. Depending on the plant species and plant parts, large differences were found in the Pb levels of typical plants within each zone. In Zone A, Vaccinium uliginosum and Rhododendron redowskianum had higher Pb levels than the other plants. In Zone C, the Pb levels in the branches of both plant species were higher than those in the leaves, which was contrary to Zone D. In Zone B, the Pb levels in the plant parts varied greatly with plant species.

The value of B7-H3 expression in expressed prostatic secretions in differential diagnosis of patients with inflammatory elevation of PSA in t-PSA gray zone

Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred and sixteen patients from ages of 19 to 80 years ( mean,40 years) were studied. In the group there

Glacier variations and their response to climate change in an arid inland river basin of Northwest China

Glaciers are a critical freshwater resource of river recharge in arid areas around the world.In recent decades,glaciers have shown evidence of retreat due to climate change,and the accelerated ablation of glaciers and associated impacts on water resources have received widespread attention.Glacier variations result from climate change,so they can serve as an indicator of climate change.Considering the climatic differences in different elevation ranges,it is worthwhile to explore whether different responses exist between glacier area and air temperature in each elevation zone.In this study,we selected a typical arid inland river basin(Sugan Lake Basin)in the western Qilian Mountains of Northwest China to analyze the glacier variations and their response to climate change.The glacier area data from 1989 to 2016 were delineated using Landsat Thematic Mapper(TM),Enhanced TM+(ETM+)and Operational Land Imager(OLI)images.We compared the relationships between glacier area and air temperature at seven meteorological stations in the glacier-covered areas and in the Sugan Lake Basin,and further analyzed the relationship between glacier area and mean air temperature of the glacier surfaces in July–August in the elevation range of 4700–5500 m a.s.l.by the linear regression method and correlation analysis.In addition,based on the linear regression relationship established between glacier area and air temperature in each elevation zone,we predicted glacier areas under future climate scenarios during the periods of 2046–2065 and 2081–2100.The results indicate that the glaciers experienced a remarkable shrinkage from 1989 to 2016 with a shrinkage rate of–1.61 km^2/a(–0.5%/a),and the rising temperature is the decisive factor dominating glacial retreat;there is a significant negative linear correlation between glacier area and mean air temperature of the glacier surfaces in July–August in each elevation zone from 1989 to 2016.The variations in glaciers are far less sensitive to changes in precipitation than to changes in air temperature.Due to the influence of climate and topographic conditions,the distribution of glacier area and the rate of glacier ablation first increased and then decreased in different elevation zones.The trend in glacier shrinkage will continue because air temperature will continue to increase in the future,and the result of glacier retreat in each elevation zone will be slightly slower than that in the entire study area.Quantitative glacier research can more accurately reflect the response of glacier variations to climate change,and the regression relationship can be used to predict the areas of glaciers under future climate scenarios.These conclusions can offer effective references for assessing glacier variations and their response to climate change in arid inland river basins in Northwest China as well as other similar regions in the world.