人肝癌中Lewis抗原,α1,3岩藻糖转移酶与转移倾向

为了测定人原发性肝癌中Ｌｅｗｉｓ抗原和α１,３岩灌糖转移酶（ＦｕｃＴ）亚型的表达,及其与癌栓形成和转移抑制基因ｎｍ２３－Ｈ１表达的关系,用免疫组化法测Ｌｅｗｉｓ抗原,用Ｎｏｒｔｈｅｒｎ印迹法测ＦｕｃＴ和ＮＭ２３－Ｈ１的ｍＲＮＡ。结果表明,肝癌组织中ＳＬｅ＾ｘ、Ｌｅ＾ｘ、ＳＤＬｅ＾ｘ、ＳＬｅ＾ａ４和Ｌｅｗｉｓ抗原表达的 率均在８０％左右。其中ＳＬｅ＾ｘ表达较多,Ｌｅ＾ｘ和ＳＬｅ＾ａ较少,ＳＤＬｅ＾ｘ     

根据分子连接性指数和基团校正因子预测有机化合物在鱼体中的生物富集因子

研究了２３９种有机化合物的ＢＣＦ预测模型,结果显示根据分子连接性指数（ＭＣＩ）的线性模型不能准确计算及极性化合物的ＢＣＦ,也不适用于超疏水性化合物,在模型中引入基团校正因子后,极性经合物的计算误差明显降低。对数据进行曲线拟合,所得模型的估算精度进一步提高,最终确定以（＾０ｘ＾ｖ）＾２、（＾２ｘ＾ｖ）＾１／２、＾２ｘ、＾３ｘｃ、＾０ｘ＾ｖ及ＯＨ、ＮＨ２、ＮＯ２、ＮＣＯＯ等１０个基团校正团子为参数建立     

稀疏效应下Ⅲ型功能反应系统的定性分析

本文对具稀疏效应和ＨｏｌｌｉｎｇⅢ型功能反应的食饵－捕食系统｛ｘ＝ｘ＾２（ｂ／ｓ＋ｘ－ａ）（１＋βｘ＾２）－ａｘ＾２ｙ,ｙ＝ｙ（ωｘ＾２－ｅ）进行了定性分析,给出了唯一正平衡点全局渐近稳定的充分条件等一些定性性质的判别准则和生态意义,系统中正参数的变化是大范围的。     

影响禾谷缢管蚜种群密度的因子分析

运用回归分析、通径分析和网络理论探讨了小麦植株体内氨基酸、蔗糖、水分和温度、光照等因子对禾谷缢管蚜种群量及其胚胎数的单个影响和综合作用。结果表明,单个因子对麦蚜的作用符合二次多项式ｙ２＝ａ＋ｂ１ｘ＋ｂ２ｘ＾２或三次多项式ｙ３＝ａ＋ｂ１ｘ＋ｂ２ｘ＾２＋ｂ３ｘ＾３关系,５个因子的共同作用以多元非线性回归模型ｙ＝ａ＋ΣΣ（ｂｉｊｘｉ＾ｊ）＋ΣΣ（ｂｉｊｘｉ＇ｊ＇ｘｉ＾ｊｘｉ＇＾ｊ＇）拟合比较合理。计算结     

葡萄糖测定方法的比较研究

比较了传统斐林定糖,葡萄糖氧化酶－过氧化物酶比色法,葡萄糖氧化酶电极自动分析仪法测定葡萄糖。比较测定了的结果显示,三法的平均标准误差（ＳＤ）,变异系数（ＣＶ）均十分接近。通过对此三种方法的回归相关性分析显示：斐林法－酶终点比色法的回归方程为ｙ＝０．９８４３ｘ＋６．３２３９,相关系数Ｒ＾２＝０．９９８９,斐林法－自动分析仪法的回归方程为ｙ＝１．００８８ｘ＋２．０４８３,相关系数Ｒ＾２＝０．９９９１,     

一种自适应的种群增长模型及参数估计

通过对种群增长的非线性制约机制的数学形态分析,提出了一种新的种群增长数学模型ｄｘ／ｄｔ＝ｒｘ（１－（ｘ／ｘｍ）＾ｓ）其解析解为：ｘ（ｔ）＝ｘｍ／（１＋（ｘ＾ｓｍ／ｘ＾ｓ０－１）ｅ＾－ｒｓｔ）＾１／ｓ该模型当非线性密度制约指数ｓ〈１,ｓ＝１,ｓ〉１及ｓ→∞时分别对尖于ＳｍｉｔｈＬｏｇｉｓｔｉｃ,崔－Ｌａｗｓｏｎ及指数增长模型,具有自适应性,本文还提出了一种种群增长模型对数估计的搜索寻优方法,只要给出     

眼镜王蛇蛇毒神经毒素CM—11三级结构的确定

在完成了眼镜王蛇毒液抽提秀ＣＭ－１１的残基质子谱峰归属和二级结构的判定后,利用＾１Ｈ的ＮＯＥＳＹ谱和ＤＱＦ－ＣＯＳＹ谱选取了距离约束,测定了Φ角和ｘ１,并做了部分β＾１上立体归属。利用度量矩阵距离几何法计算了其三维空间结构,并进行了结构的优化。     

肉桂立木材积表的编制及优化

根据１４３株样木资料，选择材积方程Ｖ－ａＤ＾ｂ和Ｖ－ａＤ＾ｂＨ＾ｃ编制肉桂人工林一元、二元立木材积表，并用改进单纯形法进行优化，材积表经过检验，证明在生产上有实用价值。     

广东眼镜王蛇毒酸性磷脂酶A2的分离纯化及抗血小板聚集作用

目的 研究眼镜王蛇毒中酸性磷酸脂酶Ａ２对血小板的作用。方法 采用ＣＭ－Ｓｅｐｈａｄｅｓｘ Ｃ－２５Ｓｅｐｈａｄｅｘ Ｇ－７５,ＤＥＡＥ－Ｓｅｐ「ｈａｄｅｘＡ－２５,Ｓｅｐｈａｄｅｘ Ｇ－７５多步柱层析法,聚丙烯酰胺产胶电泳,酸性磷脂酶Ａ２酶活性测定;血小板聚集实验。累进要从粗中分离纯化出一酸性磷脂酶Ａ２单体,分子量为１４ＫＤ;等电点ＰＩ３．８;ＰＬＡ２比值２０μｍｏｌ．ｍｇ＾－１．ｍｉｎ＾－１;小     

Ox-LDL和天然LDL诱导人动脉平滑肌细胞增殖中蛋白激酶A作用的初步研究

汪浩川等研究表明一定量Ｏｘ－ＬＤＬ能刺激培养人动脉ＳＭＣ细胞的增殖［１］,Ｄｅｊａｇｅｒ等采用交叉抑制实验证明兔ＳＭＣ细胞膜上有能结合Ｏｘ－ＬＤＬ的清道夫受体［２］,因此Ｏｘ－ＬＤＬ诱导培养人ＳＭＣ细胞增殖可能是Ｏｘ－ＬＤＬ作用于ＳＭＣ膜清道夫受体后...     

Iron-dependent vs. iron-independent cold-induced injury to cultured rat hepatocytes: a comparative study in physiological media and organ preservation solutions

We previously described the entity of cold-induced apoptosis to rat hepatocytes and characterized its major, iron-dependent pathway. However, after cold incubation in some solutions, e.g. cell culture medium, hepatocytes show an additional, yet uncharacterized component of cold-induced injury. We here assessed the effects of organ preservation solutions on both components of cold-induced injury and tried to further characterize the iron-independent component. None of the preservation solutions (University of Wisconsin, histidine-tryptophan-ketoglutarate, Euro-Collins, histidine-lactobionate, sodium-lactobionate-sucrose and Celsior solutions) provided significant protection against cold-induced cell injury (LDH release after 24-h cold incubation/3h rewarming >65% for all solutions); three solutions even enhanced cold-induced injury. However, when the predominant iron-dependent mechanism was eliminated by the addition of iron chelators, all preservation solutions yielded hepatocyte protection that was clearly superior to the one obtainable in cell culture medium or Krebs-Henseleit buffer with iron chelators (LDH release after 24-h cold incubation/3h rewarming 相似文献   

Inherent toxicity of organ preservation solutions to cultured hepatocytes

Organ preservation solutions have been designed to protect grafts against the injury inflicted by cold ischemia. However, toxicity of University of Wisconsin (UW) solution during rewarming has been reported. Therefore, we here assessed the toxicity of UW, histidine-tryptophan-ketoglutarate (HTK), Euro-Collins, histidine-lactobionate (HL), sodium-lactobionate-sucrose and Celsior solutions in cultured hepatocytes under hypothermic (4 °C), intermediate (21 °C) and physiological (37 °C) conditions. Marked toxicity of UW, HTK, HL and Euro-Collins solutions was observed at both 37 and 21 °C. With the exception of UW solution, these solutions also increased cell injury during cold incubation (LDH release after 18 h at 4 °C: HTK 76 ± 2%, Euro-Collins 78 ± 17%, HL 81 ± 15%; control: Krebs-Henseleit buffer 20 ± 6%). Testing of individual components using modified Krebs-Henseleit buffers suggested that histidine and phosphate are responsible for (part of) this toxicity. These potential toxicities should be taken into account in the development of future preservation solutions.     

连续流条件下的竞争种群的共存态

应用分解法研究源自Ｃｈｅｍｏｓｔａｔ中的竞争作用的初值问题，并改进Ａｄｏｍｉａｎ多项式的前两项。     

Column Leaching Using Dry Soil to Estimate Solid-Solution Partitioning Observed in Zero-Tension Lysimeters. 1. Method Development

In order to understand the reactions taking place between the soil solid phase and the soil solution, we require knowledge of the chemistry of the soil solution as it occurs in the field. This knowledge allows us to conduct experiments with environmentally relevant concentrations of macro and microelements in solution. Zero-tension lysimeters directly sample the mobile fraction of soil solutions. Unfortunately, they are expensive to sample and require long equilibration periods. Other solution extraction methods do not provide solutions similar in concentration to lysimeters, either because they sample a different fraction of the soil solution or due to the impacts of the sampling process. The processes that produce lysimeter solutions cannot be emulated; however, to estimate lysimeter solution chemistry, we developed a standard protocol to produce solutions that resemble lysimeter solutions from podzolic soils using air-dried samples. We washed air-dried soil columns sequentially with de-ionized water until the electrical conductivity (EC) of the leachates stabilized and then leached the columns using an environmentally relevant concentration of a weak salt solution. We hypothesize that the stabilization point of the EC of the soil solution is indicative of the point at which soluble salts and organic material precipitated during sampling and storage are removed from the soil surface. Solutions produced by leaching, once the EC of wash solutions had stabilized, were comparable to lysimeter solutions from the area where samples were collected with respect to the concentrations of divalent cations, pH, EC and DOC.     

一类带时滞竞争模型的周期解

研究了来源于水生种群植化相克的模型,提出了带时滞的半线性抛物系统．用上下解方法讨论了抛物方程组周期解存在性的原理,利用特征函数构造所提出抛物系统的上解,给出了正周期解存在的充分条件．     

Emerging applications of small angle solution scattering in structural biology

Small angle solution X‐ray and neutron scattering recently resurfaced as powerful tools to address an array of biological problems including folding, intrinsic disorder, conformational transitions, macromolecular crowding, and self or hetero‐assembling of biomacromolecules. In addition, small angle solution scattering complements crystallography, nuclear magnetic resonance spectroscopy, and other structural methods to aid in the structure determinations of multidomain or multicomponent proteins or nucleoprotein assemblies. Neutron scattering with hydrogen/deuterium contrast variation, or X‐ray scattering with sucrose contrast variation to a certain extent, is a convenient tool for characterizing the organizations of two‐component systems such as a nucleoprotein or a lipid‐protein assembly. Time‐resolved small and wide‐angle solution scattering to study biological processes in real time, and the use of localized heavy‐atom labeling and anomalous solution scattering for applications as FRET‐like molecular rulers, are amongst promising newer developments. Despite the challenges in data analysis and interpretation, these X‐ray/neutron solution scattering based approaches hold great promise for understanding a wide variety of complex processes prevalent in the biological milieu.     

Algal growth dynamics under light interaction: A nonlinear evolution problem

A mathematical model for interaction of algae with light is presented. This model consists of a couple of nonlinear integro-differential equations dealing with the evolution of algae concentration due to absorption of light and the evolution of light intensity due to absorption and scattering by algae and water. The model is formulated as a nonlinear abstract Cauchy problem in a Banach space suited to describe the physical features of the problem. By using techniques and results of semigroups theory, it is proved that the system has a unique global strict solution.Work performed under the auspices of G.N.F.M. (Gruppo Nazionale per la Fisica Matematica)     

The influence of short-term fasting on the quality of small bowel graft preservation

INTRODUCTION: Donor nutritional status may be a determinant of small bowel (SB) quality following storage. In this study, we investigated the effect of donor nutritional status and a proven nutrient-rich preservation solution on graft quality following cold storage. METHODS: Rats were fasted (12-14 h) or non-fasted. SB (n=6) was flushed vascularly with modified University of Wisconsin (UW) solution and flushed luminally with UW or an amino acid-rich (AA) solution as follows: Fasted. UWV, none; UWL, UW solution; AAL, AA solution. Non-fasted. UWV, none; UWL, UW solution; AAL, AA solution. Energetics, peroxidation (malondialdehyde; MDA), glutathione and histology were assessed over 24 h at 4 degrees C. RESULTS: Energetics (ATP, ATP/ADP, and energy charge) were significantly higher in AAL (fasted and non-fasted) groups than other groups. However, there were no differences in energetics parameters between fasted and non-fasted animals in all groups. MDA was higher in fasted groups than non-fasted tissues; interestingly, AAL values were up to 10-fold lower than other groups. Higher glutathione levels were detected in non-fasted AAL tissues. Mucosal integrity was markedly superior in luminally treated tissues (UWL and AAL) in fasted and non-fasted states. Most noteably, AAL tissues from fasted animals exhibited grade 2 injury (villus clefting), whereas normal mucosa was observed in non-fasted tissues (grade 0). CONCLUSION: Luminal flushing and a nutrient-rich preservation solution improve energetics, oxidative stress, and mucosal integrity during storage. Poorer donor nutritional status does not affect energetics throughout storage, but causes mucosal injury as a result of increased oxidative stress, even after a brief period of donor fasting.     

时变环境Lotka—Volterra系统的渐近性态

本文研究时变环境下的Lotka-Volterra系统,给出一系列关于这类系统持久性以及正T-周期解全局渐近稳定的充分条件．     

Willis环状脑动脉瘤生物数学模型的周期与概周期解

本文运用构造Liapunov函数的方法,在一定条件下,证明了Willis环状脑动脉瘤生物数学模型存在唯一的周期与概周期解．