缺血性脑卒中脑温度的磁共振波谱研究

目的应用磁共振波谱成像(magnetic resonance spectroscopy,MRS)监测缺血性脑卒中卒中灶及脑干的温度变化.方法选取缺血性脑卒中患者15例,健康对照15例,分别于第1周及第8周行常规轴位T2WI,FLAIR及MRS扫描,测量卒中灶及脑干乙酰-天门冬氨酸(N-acety-L-asparticaca acid,NAA)化学位移,通过公式T=37+100(CSNAA-2.035)计算相应脑区温度,观察并对比分析数值的变化.结果患者卒中灶温度第1周高于第8周,差异具有统计学意义(P0.05);卒中灶温度第1周高于健康志愿者相应脑区,差异具有统计学意义(P0.05).结论 MRS能从分子水平研究缺血性脑卒中患者脑区温度变化,并有望用于评价临床疗效.     

提高农业水土资源的时空利用率,保障新世纪的粮食自给

一、迫切需要提高水土的时空利用率粮食作物种植在旱地上,每生产１公斤粮食就要消耗１吨以上的水分（图１）,大致是１亩１ｍｍ的降水量。北方农区的年降水量仅在５００ｍｍ上下。因此为了谋求每亩生产１吨粮的目标,必须借用非耕地的降水。现代社会人口剧增,各种企业勃兴,愈益需求农业来供应食品与原料,而农业需用的水源与耕地却被大量征用。我国的人均耕地较低。在迎接新世纪的到来之际,欲使粮食生产长期做到自给的困难迭增,为此必须持续提高单位面积农田产量。每年不同农区的产量,仍然要随气候而波动,特别是被降水的机遇所左右,…     

海带牛奶乳酸发酵的初步研究

用市售酸奶在加有海带汁的分离培养基上分离筛选到１３株乳酸菌株，并进行生理生化验证实验，经海带汁牛乳驯化培养发酵试验，确定两株产乳酸较高的ＬＤ＿５（保加利亚乳杆菌）和Ｓ＿（ＫＯ）（嗜热链球菌）为本研究试验菌，通过正交设计和感官评定最后得到１５％的海带汁、６．５％糖、１０％奶粉发酵配方的优良无腥味海藻凝固奶。     

Prediction of shelled shrimp weight by machine vision

The weight of shelled shrimp is an important parameter for grading process. The weight prediction of shelled shrimp by contour area is not accurate enough because of the ignorance of the shrimp thickness. In this paper, a multivariate prediction model containing area, perimeter, length, and width was established. A new calibration algorithm for extracting length of shelled shrimp was proposed, which contains binary image thinning, branch recognition and elimination, and length reconstruction, while its width was calculated during the process of length extracting. The model was further validated with another set of images from 30 shelled shrimps. For a comparison purpose, artificial neural network (ANN) was used for the shrimp weight predication. The ANN model resulted in a better prediction accuracy (with the average relative error at 2.67%), but took a tenfold increase in calculation time compared with the weight-area-perimeter (WAP) model (with the average relative error at 3.02%). We thus conclude that the WAP model is a better method for the prediction of the weight of shelled red shrimp.     

非正式行为、社会交换与非正式组织博弈分析

组织内非正式行为的密集化是非正式组织形成的基础,论文通过对员工之间非正式行为的社会交换特点分析,探讨了非正式行为的社会交换的理性本质。以此为基础,最后通过博弈分析得出:非正式组织是参与者之间进行成本收益选择而形成的一个纳什均衡解。     

Alpine vascular flora of the Ruby Range, West Elk Mountains, Colorado

The Ruby Range is a northern extension of the West Elk Mountains of west central Colorado. Composed primarily of sedimentary rocks, the range is heavily faulted and intruded by many dikes and sills. Eight study areas, selected as representative of the major topographic features of the range, were analyzed floristically. A vascular flora of 220 species in 111 genera and 35 families is reported. The phytogeographic distribution of the flora is primarily alpine and western North American. The flora of the Ruby Range shows a 74% similarity to the flora of the San Juan Mountains to the southwest.     

Tundra vegetation of three cirque basins in the northern San Juan Mountains, Colorado

The vegetation of three alpine cirque basins in the northern San Juan Mountains of southwestern Colorado was inventoried and analyzed for the degree of specificity shown by vascular plant communities for certain types of habitats identified as representative of the basins. A total of 197 vascular plant species representing 31 families was inventoried. Growth forms of all species were noted and a growth form spectrum for all of the communities was derived. The caespitose monocot and erect dicot growth forms are the most important growth forms among the community dominants. The most common growth form among all species is the rosette dicot.           

CsPbBrI2 perovskites with low energy loss for high-performance indoor and outdoor photovoltaics

Over the years,the efficiency of inorganic perovskite solar cells (PSCs) has increased at an unprecedented pace.However,energy loss in the device has limited a ...     

以煤渣为填料的生物接触氧化法处理污水

研究以煤渣做填料的生物接触氧化法处理高浓度BOD污水的原理与技术;同时介绍其细菌的分离及培养、挂膜技术及运行工艺过程等.本法与其他比较,有占地面积小,经济高效的优越性.     

Precise measurement of single molecule and single cell based on nanopores/nanochannels'charge transfer

Diseases often come from a cell or even a molecule misperforms its function.Obtaining fluctuation of nucleic acids,proteins,gly-cans and other biomolecules is h...