抗牛布鲁氏菌独特型抗体杂交瘤细胞（Ｆ９）的生长和代谢

用RPMI1640培养基对抗牛布鲁氏菌独特型抗体杂交瘤细胞株(F9)进行培养，并对其生长代谢进行测定。该细胞不论接种1.1×10     

Biocrusts resist runoff erosion through direct physical protection and indirect modification of soil properties

Purpose

Biological soil crusts (biocrusts) are ubiquitous in arid and semi-arid regions and play many critical roles in soil stabilization and erosion prevention, greatly decreasing soil loss. Although sediments may be completely controlled by well-developed biocrusts, runoff loss is observed. Consequently, it is important to study how biocrusts resist runoff erosion in different developmental stages to evaluate and manage water erosion.

Materials and methods

In the Loess Plateau Region, we sampled 32 biocrust plots representing eight stages of biocrust development and 5 slope cropland soil plots as bare soil control plots. We then used a rectangular open channel hydraulic flume to test the effects of biocrust development on runoff erosion.

Results and discussion

As expected, the establishment of biocrusts enhanced soil stability, and accordingly, soil anti-scourability significantly increased with biocrust development. Biocrusts exhibiting more than 36% or 1.22 g dm^?2 of moss coverage or biomass fully protected the soil from runoff erosion. Moreover, soil properties, such as soil organic matter, soil cohesion and soil bulk density, were also important in reducing erosion. The findings indicated that biocrusts inhibited runoff erosion through direct physical protection related to biocrust cover and biomass and through the indirect modification of soil properties. In the early biocrust development stage (when moss cover was less than 36%), cyanobacterial biocrust played a primary role in providing resistance to runoff erosion, with resistance being positively related to cyanobacterial biomass (chlorophyll a) and influenced by soil properties.

Conclusions

The relationship between soil anti-scourability and moss coverage or biomass can be divided into two stages based on a moss cover or biomass threshold. The capacity of biocrusts to resist runoff erosion was limited when moss cover was below the threshold value. Therefore, the stage corresponding to this level of moss cover should be of concern when estimating, predicting and managing water erosion.

     

应用GNU Zebra实现OSPF

利用GUN Zebra在Linux下实现了路由器的功能,这种路由器能支持多种路由协议,以OSPF为例,阐述了配置的过程。     

基于光释光测年法的三江源地区高山草甸土形成年代与成因研究

[目的]分析三江源区高山草甸土壤的年代及发生发育过程,为维系该区土壤安全和生态安全提供指导.[方法]采用粗颗粒石英与钾长石光释光(OSL)测年法,对三江源区4个高山草甸土剖面夏琼(XQ)、歇武(XW)、桐勒栋(TLD)、斗地村(DDC)土壤的形成发育时间进行研究,结合土壤粒度、元素地球化学特征分析该区土壤形成过程.[结...     

智能消防应急平台的发展构想

文章提出的智能消防应急平台正是针对这些痛点而进行的发展构想,它以变电站三维模型作为信号传输载体,实现设备监控、直观展示、救援规划三部分功能优化。关键技术包括图像识别与多传感器信息融合、三维设计模型展示以及救火路径规划。智能消防应急平台的工作流程模型展示出其对于消防安全能力提升的巨大潜力,若能克服主要技术难点得到实施,本平台预期将产生很大的经济与社会效益。     

诱导轮偏转角对离心泵叶轮空化性能的影响

为了阐明诱导轮偏转角对离心泵叶轮空化性能的影响,改善离心泵的空化性能,找到最佳周向位置,基于均相流假设,采用IDM空化模型与RNG k-ε湍流模型,先选取诱导轮偏转角分别为0°,10°,20°,30°,40°,50°共6种方案,对离心泵外特性及诱导轮和叶轮空化性能进行数值模拟和试验对比,得到不同方案下离心泵的性能数据.计算得到的NPSHR曲线与试验数据吻合较好,验证了计算方法的准确性;基于数值模拟结果,分析了不同偏转角下诱导轮与叶轮内气泡分布规律,发现不同偏转角下诱导轮和叶轮内空化发展过程及气泡发展规律基本相同,但偏转角为10°时气泡发展速度较慢、各空化阶段分布面积较小,进一步选择5°和15°偏转角进行计算分析,得到更精确的结论,即诱导轮偏转角为5°时离心泵的综合水力性能最优.     

1株秦艽内生真菌的分离鉴定及生物活性研究

[目的]从药用植物秦艽的叶中分离1株内生真菌,并对抗氧化、抑菌等生物学活性进行分析,为进一步研究其作用机理及应用价值提供基础.[方法]用组织分离法从秦艽的叶中分离纯化了1株内生真菌菌株,采用形态学结合rDNA ITS区、LSU基因序列鉴定菌株;采用PCR技术扩增菌株的PKS基因;采用DPPH法检测发酵液的乙酸乙酯萃取物...     

基于遥感的京西北山地森林景观格局特征及动态

通过1991、1999年和2007年LandsatTM3期遥感影像,在地理信息系统支持下,应用景观生态学原理与方法,进行图像解译和景观分类并计算景观指数,对北京西北部山地森林近16a来的景观格局变化进行分析.结果表明:1991-2007年,林地始终是研究区的景观基质,前8a林地面积减少,后8a面积回升;各景观要素面积随...     

The activation of p38MAPK and JNK pathways in bovine herpesvirus 1 infected MDBK cells

We have shown previously that BHV-1 infection activates Erk1/2 signaling. Here, we show that BHV-1 provoked an early-stage transient and late-stage sustained activation of JNK, p38MAPK and c-Jun signaling in MDBK cells. C-Jun phosphorylation was dependent on JNK. These early events were partially due to the viral entry process. Unexpectedly, reactive oxygen species were not involved in the later activation phase. Interestingly, only activated JNK facilitated the viral multiplication identified through both chemical inhibitor and siRNA. Collectively, this study provides insight into our understanding of early stages of BHV-1 infection.