基于质量分级的马铃薯贮藏温度特性的试验与研究

贮藏室内适宜的贮藏温度是进行科学贮藏和决定贮藏质量的重要条件.为研究相同贮藏条件下不同质量马铃薯堆内部温度的差异,以内蒙古半地下式马铃薯贮藏室为试验场地,将食用型"冀张226"马铃薯按单薯质量进行分级,以筐装方式进行堆码,同时用传感器采集贮藏过程中的温度数据,然后对数据进行分析、对比.结果表明:整个贮藏过程中,分级后的所有马铃薯堆的内部温度整体变化规律基本一致,均为先降低后升高,但单薯质量小的马铃薯堆内部温度的稳定性要优于单薯质量大的马铃薯堆.温度下降阶段,马铃薯堆的内部温度与马铃薯单薯质量大小呈负相关;温度上升阶段,马铃薯堆内部温度上升率与马铃薯单薯质量呈正相关;不同马铃薯堆在贮藏过程中的最低温度与马铃薯单薯质量呈负相关;分级后的马铃薯堆内部温度的稳定性要优于未分级的马铃薯堆.     

Growth Characteristics of the WF2 Cell Cultures

Fish cell lines have been developed and utilized since the early 1960s and a wide range of fish species are now represented in culture (Wolf and Mann 1980; Fryer and Lannan 1994). However, the fish species most often represented in cell cultures are those of significant economic importance in aquaculture. Fish cell lines were initially cultured for use as a diagnostic and research tool, particularly for diagnosis of viral diseases and research focused on them. In more recent years they have been used in the fields of toxicology, gene regulation, gene expression, DNA replication and repair, and cancer research (Fryer and Lannan 1994). The increase in fish cell use can be explained by the ease with which they can be cultured. For example, fish cell lines do quite well on a passage schedule of 7–14 d (sometimes even greater) and usually do not require a change of medium between passages. This is quite in contrast to mammalian cell cultures, which require much more time and attention (Lannan 1994).     

Pharmacokinetics of Oxytetracycline in Nile Tilapia Oreodromis niloticus Challenged with Streptococcus iniae and Vibrio vulnificus

Tissue depletion studies of antibacterials are an important part of data packages required to obtain a label from the U.S. Food and Drug Administration (FDA) in the United States for use of therapeutants in food fishes. Currently, withdrawal tima are set based on results of such studies obtained from healthy animals. Bacterial infection can lead to dramatic physiological changes in affected fish. In this investigation, the impact of bacterial infection on depletion kinetics of oxytetracycline (OTC) was examined in tilapia Oreochromis niloticus challenged with Streptococcus iniae (a model Gram positive bacterium) or Vibrio vulnificus (a model Gram negative bacterium). An additional group of fish injected with Brain Heart Infusion (BHI) broth was included as a non-infectious stimulus. Although some differences in elimination kinetics of OTC were observed between treated fish and non-treated controls, OTC was rapidly eliminated from tilapia in all groups. In all cases, mean concentration of OTC was below the current 2.0 ppm (μg/g) FDA tolerance for OTC in the edible portion (muscle plus skin) after day 3 postdosing.     

Toxicity of Hydrogen Peroxide to Pre-exposed Young-of-the-Year Walleye: Effects of Water Hardness and Age of Fish

Abstract.— Young-of-the-year (Age 0+) walleyes Stizostedion vitreum were exposed to hydrogen peroxide at 10 mg/L for 1 h in an effort to increase their tolerance to subsequent exposures to hydrogen peroxide at therapeutic concentrations that are considered to be toxic. The effects of age of fish and water hardness on the effectiveness of this pre-treatment protocol were examined. Trials were performed in fish at four ages (50-d, 60-d, 86-d, and 95-d post-hatch) and under three different water quality conditions (soft water: hardness = 64.4 mg/L, alkalinity = 56.5 mg/L; medium hard water: hardness = 103.3 mg/L, alkalinity = 51.5 mg/ L; hard water: hardness = 130.3 mg/L, alkalinity = 92 mg/L). A benefit of pre-treatment was only observed when it was performed under hard water conditions and only with walleyes at 60- and 86-d post hatch. The pre-treatment protocol appeared to be detrimental to fish in the youngest age group (50-d post-hatch) under all three water quality conditions.     

黄土高原丘陵沟壑区土壤水资源平衡利用与生态植被可持续发展

黄土高原丘陵沟壑区林草植被建设对控制水土流失和农业可持续发展具有双重意义。但是,大量资 料表明,黄土高原丘陵沟壑区林地和草地土壤水分严重亏缺,林草植被对土壤水资源的过度利用必将产生严 重后果,笔者强调生态植被建设须坚持土壤水资源平衡利用原则。在对土壤水量收入和支出诸因素分析的基 础上,指出采取拦蓄降水、降水高效叠加利用、覆盖保墒和减少植被蒸腾等途径及措施,以实现土壤水资源平 衡利用。提出林地降水高效叠加利用技术的思路及研究解决办法;研究建立植物蒸腾耗水量评价指标体系, 为筛选节水植物种类或种提供科学依据;植被蒸腾量的调控,根据叶面积指数与土壤耗水量的关系,在土壤水 资源平衡利用的原则下,确定其盖度和种植密度,后期通过控制树冠、适度疏枝、合理平茬(刈割)等进一步加 以调节。     

原发性肾病综合征并发急性肾功能衰竭的临床与病理分析

目的；观察原发性肾病综合征(iNS)并发急性肾功能衰竭(ARF)的临床与病理。方法：对42例iNS并发ARF患者临床和病理改变进行分析。结果：iNS并发ARF的发生率为5．87％，临床上以少尿型为主(78．6％)．起病均在iNS的急性期。42例患者临床表现为大量蛋白尿、高度水肿，病程中无明显诱因出现少尿，尿素氮与血清肌酐增高。肾脏病理检查肾小球以轻微改变为主，其中微小病变型16例．轻度系膜增生型肾炎2l例；肾小管间质的病变却表现为广泛肾间质水肿及小管上皮细胞灶性坏死。经利尿、强的松等治疗后，36例患者肾功能逐渐恢复正常。结论：iINS并发ARF多发生于肾小球轻微改变者；尽早明确iNS并发ARF，并给予适当治疗，绝大多数患者肾功能可以恢复。     

两种吡虫啉种衣剂在棉花和土壤中的残留动态研究

采用田间试验方法，研究了两种吡虫啉种衣剂在棉花和土壤中的残留消解动态，并对其在棉花上使用的安全性作出了评价。结果表明，两种吡虫啉种衣剂无论在棉株中或土壤中消解动态没有显著差异，其消解速度相当缓慢，有较长的药效。试验还表明，无论是推荐药量还是加倍药量．在正常使用条件下，都不会造成棉子残毒污染和土壤的残留积累。     

Spatio-temporal variation in serum chemistry of the lobster, Homarus americanus Milne-Edwards

Monthly variations in serum chemistry of the American lobster, Homarus americanus Milne-Edwards, were investigated at one location in Long Island Sound (LIS). Comparisons between three locations within and outside LIS were also made for a single time point. Most serum analytes displayed significant fluctuation over the study period and between locations. Temporal patterns could be classified as: low in cool months/high in warm months, i.e. Na, Cl, Na:K ratio, Ca, albumin:globulin ratio, percentage Fe saturation; high in cool months/low in warm months, i.e. pH, K, urea, total protein, albumin, globulin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), lipaemia; June spike, i.e. glucose, cholesterol, creatine kinase, iron, transferrin iron-binding capacity; other less obvious fluctuations, i.e. Mg, PO4; and no apparent fluctuation, i.e. HCO3, alkaline phosphatase. The proportion of samples correctly classified into month of collection by a subset of 13 analytes using discriminant analysis improved as the months progressed from May (0.75) to October (>0.95). Discriminant analysis also resolved 96.5% of samples by location. The significant depression of serum calcium at the eastern LIS site correlates with excretory calcinosis, a calcium storage disease described from lobsters at this site, but contrasts with a seasonal elevation in serum calcium recorded in the temporal component of the study. Serum proteins, the electrolytes Ca and K and the enzymes ALT and AST proved to have the strongest spatio-temporal patterns of variation. Serum chemistry is a useful research tool for lobster populations, but the dearth of information on the homology of analyte functions in this species with those in vertebrate species makes interpretation of the results challenging. Late summer/autumn water conditions appear to cause stress for lobsters in LIS.