高校图书馆电子阅览室管理和服务

本文介绍湖南科技大学图书馆电子阅览室管理现状与管理系统,探讨高校图书馆电子阅览室的软、硬件的管理维护,推行读者柔性管理和开展电子阅览室特色服务的途径。     

不同调酸剂对种植玉米红壤微生物群落的影响

为研究红壤微生物丰度和群落组成对不同调酸剂的响应,分析影响碳/氮关键代谢过程微生物的变化,通过盆栽实验,设置不施肥（CK）、钙镁复合剂（L）、钙镁复合剂配施猪粪（ML）和钙镁复合剂配施秸秆（SL）4个处理,采用宏基因组测序技术,分析土壤细菌、真菌和古菌以及碳/氮代谢关键过程微生物。结果表明：L、ML和SL处理显著提高土壤pH值和交换性钙/镁,显著降低土壤交换性酸。调酸剂增加了细菌优势菌中的变形菌门相对丰度,降低了绿弯菌门和酸杆菌门相对丰度;降低了真菌优势菌中的毛霉菌门相对丰度;增加了古菌优势菌中的广古菌门和深古菌门的相对丰度,降低了奇古菌门的相对丰度。冗余分析结果显示,速效钾是影响土壤细菌和真菌群落结构的主要环境因子,土壤pH和有机碳是影响土壤真菌和古菌群落结构组成的关键因子。碳代谢过程的贡献度方面,变形菌门的贡献度在SL处理中最高,放线菌门和芽单胞菌门的贡献度在ML处理中最高。氮代谢过程中,各处理绿弯菌门对硝化作用的贡献率均超过80%。调酸降低了绿弯菌门和酸杆菌门在反硝化与硝酸盐异化还原过程中的贡献度,L与SL处理的变形菌门贡献度低于ML处理,而ML处理的放线菌门贡献度高于L与SL处...     

温度、光照强度和光照周期对铜藻有机碳释放速率的影响

为探究铜藻(Sargassum horneri)的有机碳释放速率、与净初级生产力(NPP)之间的关系及主要的调控因素等问题,本研究采用三变量三水平的正交实验,测定铜藻在不同温度(5、15和25℃)、光照[86、172和258 μmol/(m2·s)]和光照周期(L∶D=6 h∶18 h、L∶D=12 h∶12 h、L∶D=24 h∶0 h,L表示光照时长,D表示黑暗时长)条件下溶解有机碳(DOC)、颗粒有机碳(POC)的释放速率和初级生产力。结果显示,DOC和POC释放速率的范围分别为0.653~4.785 mg/(g·h)和0.066~0.322 mg/(g·h);温度和光照强度分别是铜藻释放DOC和POC的主要调控因素;铜藻在高温、中光、L∶D=6 h∶18 h条件下的DOC释放速率最高[4.785 mg/(g·h)],在高温、高光、L∶D=24 h∶0 h条件下的POC释放速率最高[0.322 mg/(g·h)];铜藻释放的DOC和POC占NPP的比值分别为4%~130%和0.4%~5.9%;DOC释放速率与NPP之间存在负相关关系,POC释放速率与NPP之间无明显相关性。研究结果为深入了解铜藻的生理生态学特性及其对沿海生态系统碳循环的影响提供了科技支撑。     

天山北坡经济带人口分布与经济发展研究

人口分布是影响经济发展的重要因素。人口分布与经济分布的最基本属性是不均衡性,人口与经济的空间集中化是区域发展的内在规律。本文从人口与经济发展的关系出发,通过对天山北坡经济带人口数量、人口密度、人口分布等因素与经济发展相关关系及动态演进的多方面分析,为天山北坡经济带进一步实施人口与经济空间集中化战略,建立起人口、经济与环境协调发展的区域格局提供一些理论依据与对策。     

民勤荒漠区主要植物的物候特性与牧草利用

通过设置样方、样点和运用物候观测,对退化荒漠植物群落进行轻度放牧利用分析,即运用植被状况与降水量的关系,分析限制植物生长的因素;运用不同稳定性沙丘的植被状况和土壤种子库资料,分析荒漠草地的可利用性和可利用程度;运用物候资料分析民勤荒漠区(灌木和草本植物)牧草利用的主要季节。结果表明:民勤荒漠草地土壤种子库中植物种子丰富,影响当地植物密度和植被盖度的关键因素是降水,可进行轻度放牧。轻度放牧时,要依据牧草展叶盛期的开始序列和果熟期的开始序列选择植物群落,实行小规模、间歇式轮牧。展叶盛期为一年中牧草的第1个利用季节,果熟期为一年中的第2个利用季节。     

物联网种菜离我们有多远？

出门前按一下手机,就可以预约要去的商场附近的停车位;驾车途中,可以随时得知前方哪些路段堵车,并得到根据车流量情况规划的新路线;身体不适时,便携式监护仪会实时将心电等生理数据传输到医院的后台服务系统;参观世博会不带门票和皮夹,用手机在闸机前一晃就能入园,还能在商店购物消费……也许,我们已经从日常生活的点滴细节里,感受到某种变化正在悄然发生,而这些变化背后的主角,正是物联网。
很多人对物联网这一新生事物可能并不了解,但物联网技术已逐渐发展起来……1999 年物联网的概念被提出后,人们以更加精细和动态的方式管理生产和生活,提高了资源利用率和生产力水平。2009 年8 月,国务院总理温家宝在无锡视察后表示,中国要抓住机遇,大力发展物联网技术。2010 年“两会”上,物联网是首次被写入政府工作报告,众多代表委员聚焦物联网,并建议将其作为国家发展战略来抓。
目前,我国农业正处于传统农业向现代农业的转型时期,全面实践这一新技术体系的转变,为现代农业发展提供了前所未有的机遇。目前,物联网技术已被应用到农业的诸多领域,包括农业环境监测、温室控制、节水灌溉、气象监测、产品安全与溯源、设备智能诊断管理等方方面面。那么,究竟什么是物联网？物联网在农业领域的应用又有哪些优势与不足？农业物联网未来的发展方向是怎样的？“本期视点”邀请相关专家就此主题与读者共同探讨。     

Effects of exosomes derived from hypoxia-preconditioned umbilical cord mesenchymal stem cells on function of endothelial cells

AIM To investigate the effect of exosomes derived from hypoxia-preconditioned human umbilical cord mesenchymal stem cells (hUCMSCs) on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs). METHODS hUCMSCs and HUVECs were isolated, cultured and identified. Exosomes derived from hUCMSCs were extracted by ultracentrifugation. The morphological change of exosomes was observed under transmission electron microscope. The particle size and concentration of exosomes were detected by nanoparticle tracking analysis, and the surface specific marker proteins of exosomes were determined by Western blot. hUCMSCs were divided into normoxia group and hypoxia group. The viability of hUCMSCs was measured by CCK-8 assay. HUVECs were divided into control group, normoxic exosome group and hypoxic exosome group. The proliferation of HUVECs was detected by EdU assay. The migration ability was detected by cell scratch assay and Transwell experiment. Tube formation ability was evaluated by tube formation experiment. RESULTS Compared with normoxia group, hypoxia pretreatment enhanced the viability and exosome release of hUCMSCs. Compared with normoxic exosome group, hypoxic exosomes enhanced the proliferation, migration and tube formation of HUVECs. CONCLUSION Exosomes derived from hUCMSCs under hypoxia enhances the proliferation, migration and tube formation of HUVECs.     

栽培柳枝稷不同生长时期对伴生杂草生物量及密度的影响

以陕西定边县引种的8个柳枝稷(Panicum virgatum L.)品种(Blackwell,Cave-in-Rock,Dakota,Forest-berg,Illinois USA,Nebraska 28,Pathfinder和Sunburst)及行间杂草作为研究对象,通过计算柳枝稷对杂草的抑制率(RI),分析其生长指标与杂草生长指标的相关关系,判定不同柳枝稷品种在不同生育期对杂草生长的抑制效应,为其引种及田间杂草管理提供依据。结果表明:在生长初期(6月30日),Illinois USA杂草抑制率仅为3.4%,Cave-in-Rock和Forestberg对杂草生长抑制率分别为86.0%和74.9%;经过2次人工除草后(8月30日),Cave-in-Rock和Forestberg的杂草抑制率分别为85.7%和95.7%;生长后期(10月13日),仅Cave-in-Rock对杂草生长有88.5%的抑制率。回归分析显示,生长中后期(8月30日),柳枝稷地上部及根系生物量显著影响对杂草的抑制率(R2=0.31,0.54;P<0.05)。Pearson相关分析发现,Cave-in-Rock的株高、地上及根系生物量均显著降低杂草单株生物量(r=-0.97,-0.99,-0.99;P<0.05);Forestberg的植高与杂草密度显著负相关(r=-0.97,P<0.05)。     

Relationship between airway inflammation and pulmonary arterial remodeling in rats with chronic bronchitis and emphysema

AIM:To study the effects of airway and pulmonary inflammation on pulmonary arterial remodeling in rats with chronic bronchitis (CB) and emphysema.METHODS:Twenty-four male Wistar rats were divided into three groups (n=8): Group A: four-weeks CB and emphysema;Group B: six-weeks CB and emphysema group;Group C: normal control.The rat model of CB and emphysema was established by intratracheal instillation of lipopolysaccharide (LPS) and daily exposure to cigarette smog.The arterial blood gas analysis,pulmonary hemodynamics changes and cell counts in bronchoalveolar lavage fluid (BALF) were measured.The pathomorphological changes of airway inflammation,alveoli destruction and pulmonary arterial remodeling were observed by HE straining and triple straining.RESULTS:(1) The characteristic pathological changes of CB and emphysema were observed in group A and B.Neutrophils were the main cells infiltrated into the walls of airway in group A.Lymphocytes and macrophages were the main cells in group B.(2) Right ventricular systolic pressure (RVSP),mean pulmonary arterial pressure (mPAP),the ratio of the weight of right ventricle/left ventricle and septum (RV/LV+S) in group A and B were significantly higher than those in group C (P<0.05).The amount of muscular artery (MA) in group A and B were significantly higher than that in group C (P<0.05).(3) In group A and B,the levels of MA,RVSP,mPAP and RV/LV+S was correlated positively with the average alveolar area,the total cell counts and differential cell counts of neutrophils,lymphocytes and macrophages in BALF,and the level of infiltration into the walls of airway,respectively (P<0.05).The positive correlation was observed with the percentage of neutrophils,lymphocytes and macrophages between group A and B (P<0.05).The amounts of MA were also correlated positively with RVSP,mPAP and RV/LV+S (P<0.05).CONCLUSIONS:(1) The pulmonary artery hypertension,the right ventricular hypertrophy and the pulmonary arterial remodeling appeared before hypoxia.These may be related with the degree of the pulmonary inflammation.(2) The characteristic of pulmonary arterial remodeling was small artery organization,and correlated positively with the changes of hemodynamics.     

海南大戟乳汁脂溶性成分GC-MS分析

以海南大戟乳汁为试材,采用冷浸法提取海南大戟乳汁脂溶性成分,利用气相色谱-质谱(GC-MS)联用技术检测其化学成分,分离共得到24个化合物,鉴定了其中的19个化合物,5个化合物未定。结果表明:海南大戟乳汁主要脂溶性成分为环阿屯醇、24-亚甲基环木菠萝烷醇、紫薇乙缩醛以及未定化合物1和未定化合物2。