国内高校图书馆学科导航建设现状调查与分析

通过对国内183所高校图书馆学科导航建设情况的调查，概述了目前国内高校图书馆学科导航的建设现状、服务模式和服务内容，并分析了其中存在的问题，提出了一些对策。     

5个番木瓜品系比较试验

选育出综合农艺性状优良、抗病性强、适宜在华南地区种植番木瓜新品种.对5个杂交选育大型番木瓜品系与对照品种穗中红48号植物学特征、主要经济性状、产量和抗病性等进行比较.品系200919平均单重和单株产量均最高,分别为1.60和20.77 kg,平均产量也最高,为46110 kg/ha,较对照差异达显著水平,其横径、可溶性固形物含量、汁等较对照均有明显优势;品系200915和200917产量分别为40530和39555 kg/ha,均较对照增产,但差异不显著;品系200916和200918较对照减产;5个供试品系抗病性均为高抗水平,调查初期,品系200919未发现感病病株,后期调查发病率较低,仅为4.2%,病情指数为0.8.品系200919具有树势强壮、高产、优质、抗环斑花叶病等优势,可继续参加下一年品比试验.     

硫醚沙星等四种药物对泥鳅的急性毒性试验

采用生物毒性试验的方法,在水温(22±1)℃条件下,用硫醚沙星、溴氯海因、指环清、季氨168、四种药物对泥鳅进行毒性试验,结果表明硫醚沙星24hLC50为167.72mg/L,安全浓度为39.745mg/L;溴氯海因24hLC50为116.6mg/L,安全浓度为50.20mg/L;指环清24hLC50为30mg/L,安全浓度为5.23mg/L;季氨168的24hLC50为60.56mg/L,安全浓度为10.37mg/L;建议指环清不能做泥鳅的治疗药物,季氨168要谨慎使用,溴氯海因及硫醚沙星可以作为泥鳅的治疗药物。     

气相色谱法测定水产品中三氯杀螨醇残留量

为拓展食品中农药残留监控范围,本文建立了水产品中三氯杀螨醇的气相色谱测定方法。试验基质为鳗鲡、罗非鱼、对虾、玻纹巴菲蛤,取其可食用组织的均匀试样1g,用正己烷超声萃取,用浓硫酸和弗罗里硅土净化,二氯甲烷／正己烷混合液淋洗层析柱。洗脱液收集和旋转蒸发浓缩后,用气相色谱法测定其中的三氯杀螨醇,外标法定量。测定仪器为HP6890N型气相色谱仪,配HP7683B型自动进样器、HP-5型毛细管气相色谱柱（30m×0．32mm×0．25μm）和。Ni微电子捕获检测器。三氯杀螨醇浓度线性范围是0．0025-0．4μg·mL-1（r=0．9998,P〈0．001）,方法定量检测下限为0．01μg·g-1。用未检出三氯杀螨醇的鳗鲡等4种试样,添加3个水平的三氯杀螨醇,分别为0．01、0．10、O．50μg·g-1,每种试样每个添加量测定6份。结果显示,加标回收率在71％-111％范围内,批内变异系数为3．2％～8．5％（n=6）,批间变异系数为2．5％～7．1％（n=4）。定量限点加标试样的回收率为73％～94％,批内变异系数为5．9％-7．7％,峰高信噪比〉10。本方法试样用量少,前处理简便,可操作性强,适合测定水产品可食部分的三氯杀螨醇残留量。     

海豚链球菌疫苗对罗非鱼免疫功能的影响

以海豚链球菌Streptococcus iniae灭活菌苗为免疫原,通过注射、浸泡、口服3种途径对体重为(100±10)g的奥尼罗非鱼Oreochromis niloticus进行免疫,在免疫前和免疫后的第3、7、10、14、21天对试验鱼进行尾静脉采血,测定其血液中自细胞的数量、各类白细胞的数量及其吞噬活性,以及血清的抗菌活力、溶菌酶活性、超氧化物歧化酶(SOD)活力及抗体水平.在免疫后第22天对所有试验鱼按照1.0×107cfu/尾进行攻毒.结果表明:各免疫组白细胞总数、淋巴细胞、嗜中性粒细胞和单核细胞数量均显著高于对照组(P<0.05);血清的抗菌活力、溶菌酶活性和抗体水平与对照组差异显著(P<0.05),SOD活力和对照组无显著差异(P0.05);免疫的罗非鱼对海豚链球菌的抵抗力明显增强,其中注射组罗非鱼的免疫能力明显高于浸泡和口服组,加强免疫组的免疫能力均有明显增强趋势.     

不同复合菌剂对玉米秸—猪粪混合原料厌氧发酵产沼气的影响

在粉碎的玉米秸秆中添加不同的复合菌剂进行预处理,研究玉米秸—猪粪混合原料厌氧发酵产沼气的能力。结果表明:添加复合菌剂处理比不添加复合菌剂处理累计产气量高10%以上;CH4含量相差不大,变化趋势基本一致。     

Comparison of birth weight and umbilical and placental characteristics of cloned and artificial insemination-derived piglets

Somatic cell nuclear transfer (SCNT)-derived piglets have significantly higher stillbirth rate and postnatal mortality rate than artificial insemination (AI)-generated piglets. The question whether the low survival rate of SCNT piglets was related to birth weight, umbilical cord or placenta development was investigated. In this study, stillbirth rate, neonatal death rate, birth weight, umbilical cord status, placental parameters and placental gene expression patterns were compared between SCNT and AI piglets. Results showed that mortality rates at birth and during the neonatal stage of SCNT piglets were significantly higher than those of AI piglets. The incidence of abnormal umbilical cord in SCNT and SCNT-liveborn (SCNT-LB) piglets was significantly higher than in AI and AI-liveborn (AI-LB) piglets. Birth weight, placental weight, placental surface area and placental efficiency in SCNT and SCNT-LB piglets were significantly lower than those of AI and AI-LB piglets. Placental expression profiles of imprinting, angiopoiesis and nutrient transport-related genes were defective in SCNT-LB piglets compared with those in AI-LB piglets. Thus, the low survival rate of SCNT piglets may be associated with abnormal umbilical cord and placenta development. These characteristics may have resulted from aberrant expression of angiogenesis, nutrient transport, and imprinting-related genes in the placentas.     

不同包装方式对低温贮藏平菇生理特性和细胞壁变化的影响

为探讨低温贮藏下不同包装方式对平菇生理特性及细胞壁变化的影响,将平菇置于5℃冰箱中冷藏,分别以敞口PE保鲜袋和封口PE保鲜袋进行试验,以完全裸露放置作为对照,分析贮藏期间不同包装方式对平菇的感官品质、丙二醛（MDA）含量、可溶性蛋白质含量、抗氧化物酶活性,细胞壁代谢相关酶活性等指标的影响,并对平菇进行石蜡切片,观察其细胞壁的微观结构变化。结果表明,随着贮藏时间的延长,与对照相比,PE保鲜袋处理的平菇保鲜效果显著提升,明显抑制了失重率、MDA含量的增加,减缓了硬度、白度（HW）值的增大,降低了蛋白质含量的损失,延缓了过氧化物酶（POD）、过氧化氢酶（CAT）和纤维素酶（Cx）活性峰值的出现,更好地保持了平菇的品质。在整个处理组中,平菇的HW值、失重率、MDA含量不断增大且封口处理低于敞口处理;硬度值逐渐减小,封口处理硬度较敞口处理低;蛋白质含量呈现先升高后降低的趋势,封口处理蛋白质含量显著低于敞口处理;POD活性先升后降,在0～4 d,封口处理POD活性高于敞口处理,4～8 d急速下降且低于敞口处理;CAT活性呈现先降再增的趋势,贮藏前期0～2 d与贮藏后期第6至第8天CAT活性较高,0～6 d敞口处理高于封口处理,后低于封口。通过对平菇菌褶石蜡切片发现,伴随着采后贮藏天数的增加,平菇子实体细胞结构变得杂乱无序、模糊不清,细胞间隙变大,且封口处理比敞口处理细胞结构有序、规整。由此可知,低温贮藏下,PE包装处理贮藏效果明显优于全部裸露放置,封口包装保鲜效果优于敞口保鲜效果。     

Vertical Distribution and Seasonal Dynamics of Fine Root Parameters for Apple Trees of Different Ages on the Loess Plateau of China

The vertical distribution pattern and seasonal dynamics of fine root parameters for the apple trees of different ages （3, 10, 15, and 20 years old） on the Loess Plateau of China were studied. Soil coring method was used to determine the vertical distribution and seasonal dynamics of fine roots at different root radial distances （1.0, 1.5, and 2.0 m from the main tree trunk）. The fine root biomass density （FRD）, fine root length density （RLD）, and specific root length （SRL）, as well as soil water content and soil temperature were also measured. The FRD and RLD for the 10, 15, and 20 years old trees reached peak values in the 20-30 cm soil layer. For the 3 years old tree, the highest FRD and RLD were observed in the 10-20 cm soil layer. The FRD and RLD decreased with increased soil depth from the 10-20 or 20-30 cm soil layer for all age apple trees. The SRL declined with the increase of tree age. The FRD at the 1.0 m radial distance from the main tree trunk was higher than that at other radial distances in the 3 and 10 years old orchard. However, in the 15 and 20 years old orchards, especially the 20 years old orchard, the FRD at the 2.0 m radial distance was nearly equal to or higher than that at the 1.0 and 1.5 m radial distances. For all the root radiuses or the tree ages, the FRD, RLD, and SRL were the highest in spring and the lowest in autumn. The age of an apple tree does not affect the vertical distribution pattern but the biomass of fine roots and the SRL. Radial distance affects the root horizontal distribution of 3 and 10 years old trees but the 15 and 20 years old trees. Additionally, effects of soil temperature and soil moisture on fine root distribution or seasonal dynamics are not significant.     

甘肃省中西部小麦白粉菌生理小种RAPD分析

利用RAPD标记对采自甘肃省中西部20个小麦白粉菌菌株进行了研究。结果表明:在用9个扩增结果比较明显的随机引物扩增得到的81个RAPD位点中,有54个具多态性,多态性位点频率(单卫星方法统计)为66.7%。根据PopGene 32软件计算的Shannon多样性指数与Nei基因指数分别为0.455 6和0.296 8,多态性频率为96.3%,说明白粉菌菌株间具有丰富的遗传多样性。聚类分析结果表明,多态性特征与菌株地理来源之间存在一定的相关性,与生理小种毒性关系不显著。