在线微透析-液相色谱-串联质谱法测定人参水提物对糖尿病脑病大鼠脑内神经活性物质的影响

评价人参水提物对糖尿病脑病大鼠学习记忆能力及脑内神经活性物质的影响。建立糖尿病模型,采用Morris水迷宫实验以逃避潜伏期(ELT)、穿越目标区域次数及中心区域(%)为指标评价大鼠的学习记忆能力。利用在线微透析-液相色谱-串联质谱法,Venusil C18柱梯度洗脱,MRM方式检测各组大鼠海马区8种神经活性物质水平并进行比较。结果表明:糖尿病大鼠人参治疗后认知能力明显改善(p<0.05);在线检测方法线性良好(R2>0.99),准确度和精密度满足分析要求;相比模型组,人参组大鼠脑内牛磺酸、乙酰胆碱水平显著升高(p<0.01),谷氨酸、丝氨酸、天门冬氨酸、γ-氨基丁酸、多巴胺和五羟色胺水平均显著降低,8种神经活性物质水平均向正常水平调节。     

长期低剂量YbCl3暴露的神经毒性评价

雌性Wistar大鼠受孕之日起以经口灌胃方式用YbCl3染毒,剂量为0.1,2.0和40 mg Yb·kg^-1体重,对照组灌生理盐水。仔鼠出生后20 d断乳并用相同剂量的YbCl3染毒。用Morris水迷宫评价学习记忆能力,并尝试从大鼠体内微量元素含量变化、大脑海马体中Ca^2＋-ATP酶活性、海马细胞内游离钙水平及脂质过氧化程度等方面评价YbCl3的神经毒性。结果显示,2.0和40 mg·kg^-1体重剂量的YbCl3长期暴露会对大鼠的学习记忆能力产生负面影响,这可能和YbCl3暴露引起的骨骼、血清、肝脏和各脑区中部分微量元素含量发生改变,Ca^2＋-ATP酶活性受到抑制,海马细胞内游离钙水平升高及脂质过氧化程度加剧等因素有关。     

长期喂饮钇对子代大鼠脑组织中基因表达的影响

通过在饮水中加入钇(0,53.4,5340 mg.L-1),使大鼠长期摄入稀土。7个月后,采用基因芯片技术检测F1子代大脑组织中的基因表达情况。结果显示,与对照组相比,高浓度组有787个基因发生了差异表达,其中505个上调表达,282个下高表达。差异表达基因与细胞受体、信号转导、离子通道有关;低浓度组有44个基因发生了差异表达,其中32个上高表达,12个下调表达。差异表达的基因与细胞骨架、细胞运动以及DNA结合蛋白密切相关。提示长期喂饮稀土钇能改变大鼠脑组织中某些基因的表达,进一步造成机体某些生理功能如学习记忆能力的变化。     

北五味子对糖尿病脑病大鼠脑中神经活性物质含量影响的在线微透析-高效液相色谱-串联质谱联用分析

采用在线微透析-高效液相色谱-串联质谱联用方法,测定了糖尿病脑病大鼠大脑海马区的8种脑递质的含量,从脑中神经活性物质的角度研究五味子改善学习记忆能力的作用机制.实验结果表明,经五味子治疗后,痴呆大鼠脑透析液中的谷氨酸(Glu)、丝氨酸(Ser)、多巴胺(DA)及5-羟色胺(5-HT)的含量显著降低(P0.05),牛磺酸(Tau)及乙酰胆碱(Ach)的含量显著升高(P0.01),天冬氨酸(Asp)和γ-氨基丁酸(GABA)的含量有降低趋势(P0.05),8种神经活性物质的水平均向正常水平发生了调节.此结果说明五味子可能通过调节糖尿病大鼠大脑中神经活性物质的含量发挥保护中枢神经系统的作用,从而改善糖尿病脑病大鼠的学习记忆能力.Morris水迷宫实验结果表明,五味子水提物可以明显缩短糖尿病脑病大鼠的逃避潜伏期,增加穿越目标区域次数及中心区域(%)(P0.05).     

培养学生记忆化学方程式的策略

在学习化学的过程中,长期困扰学生的一个问题是：如何记忆化学方程式?学生在学习中通常会陷入这样的误区：像记忆英语单词一样地记忆化学方程式。这样的行为结果不仅让学生感到苦不堪言,而且学习效率低下、学习兴趣降低,最终的结果必将导致认知水平不高。化学方程式在化学学科中所占的重要地位是每一个学习化学的人都能体会到的。掌握好化学方程式,是学好化学的基础。     

地黄提取物改善贫血大鼠记忆及其机制

地黄滋阴补血填髓,广泛用于贫血和脑疾病患者,但其功效机制尚未阐明.本文探讨地黄水提物(Rehmannia glutinosa’s water extracts,RGWE)改善血虚大鼠记忆及其滋阴补血填髓的可能机制.采用断尾放血结合注射环磷酰胺制备贫血大鼠模型,随机分溶媒组和地黄水提物3,6,10g/kg治疗组,灌服等体积自来水或不同剂量地黄水提物10天,采用Morris水迷宫观测大鼠空间记忆能力,采用酶联免疫吸附测定方法(Enzyme linked immunosorbent assay,ELISA)检测血浆红细胞生成素(EPO)水平,免疫组化和免疫蛋白印迹技术(Western blotting)检测分析脑EPO及其受体表达水平.成功制备血虚模型,表现为大鼠红细胞数和血红蛋白显著下降,与造模前比较差异显著(P<0.05),溶媒组空间记忆能力显著下降,地黄治疗组空间记忆能力明显提高,逃避潜伏期明显缩短(P<0.05),一定时间内穿越平台次数显著增多(P<0.05);免疫组化和Western blotting结果显示脑组织EPO及其受体表达、血浆EPO水平均较溶媒组明显升高(P<0.05).地黄水提物显著提高贫血...     

铅如何影响儿童的智力、行为和心理

铅对人体损害是广泛的多系统的 ,其中神经系统是最易受其损害的重要器官 ,儿童更易受害 ,且铅对儿童是以中枢神经系统损害为主。中枢神经毒性最普遍的表现形式是智力和行为 (包括感觉功能、运动能力、注意力、视觉、记忆、情感状态等 )的异常。我国天津学者岳仲彦等测定了 3 60例智力低下儿童头发中的微量元素含量 ,发现智力低下者头发锶、钙含量比正常人 (对照组 )显著降低 ,而随着智力低下程度的加重 ,头发中锌含量明显降低 ,头发中铅含量显著增加。铅如何影响儿童的智力、行为和心理     

快速高分辨液相色谱-质谱联用技术分析2型糖尿病大鼠口服四君子汤的药代动力学

研究四君子汤在2型糖尿病大鼠体内的药代动力学。 将四君子汤水提物以18 g/kg给正常大鼠和2型糖尿病大鼠灌胃,分别在不同时间点取尿液和粪便,检测其成分及代谢产物的含量;比较正常大鼠和2型糖尿病大鼠的药代动力学参数。 采用快速高分辨液相色谱-质谱联用技术对人参皂苷Rc、甘草甜素及其脱糖代谢物进行表征。 结果表明,四君子汤中人参皂苷Rc和甘草甜素在2型糖尿病大鼠体内的累计排泄率均高于正常大鼠,大部分人参皂苷通过尿液排出体外、粪便代谢为稀有人参皂苷;大部分甘草甜素在尿液和粪便中转化为甘草次酸,2型糖尿病大鼠与正常大鼠人参皂苷Rc和甘草甜素的药代动力学参数存在明显差异。 初步总结了四君子汤在体内的药代动力学机制和代谢途径。本分析方法具有高度自动化,灵敏性和准确性,这将有助于四君子汤的临床研究的不断发展。     

酶直接电化学与第三代生物传感器

本文详细地评述并展望了酶直接电化学与第三代生物传感器这个领域已取得的成果，主要内容涉及生物电催化的三个发展阶段，实现酶与电极之间的直接电子转移方法和相应机理、以及第三代酶传感器的研制。     

高三学生化学选择学习能力现状的实证研究

培养受教育者具有选择意识和科学的选择能力是培养人的主体性的重要内容,是现代教育的特征。从选择学习的心理机制出发,探究选择学习能力的本质与构成要素,以高三学生的化学学习为基础,综合运用问卷调查法、问卷测试法以及访谈法分析高三学生化学选择学习能力的现状。结果表明:相当一部分学生自主选择意识薄弱;识别选择条件能力欠缺;不能根据自身情况做出科学合理的选择学习判断;在实施选择活动过程中,不能勇敢地面对和克服学习中遇到的困难和障碍、学生认知结构不够完善、思维品质较低、算法优化意识和能力严重缺失,不能保质保量地完成学习任务;缺乏反思意识,后续学习效率低下。     

H2在WO3表面解离吸附反应的第一性原理研究

采用第一性原理方法对H2在WO3表面的解离吸附反应进行了研究.首先通过清洁表面模型的计算,证明了c(2×2)重构表面是最稳定的WO3(001)表面构型;进而研究了4种可能的H2解离吸附模型,结果表明最可能的吸附反应为两个氢原子吸附在表面O1c原子上,氢原子被氧化在表面形成水,同时伴随着产生一个表面氧空位.态密度结果表明氢的吸附导致体系能带下移,导带部分填充电子,从而阐明了实验中WO3吸附H2后电导率上升的微观机理.     

Studies on the cure reaction and thermal properties of NADIC/phthalic anhydride modified unsaturated (epoxy) polyesters

In pseudo bi-component separated-stage model (PBSM), the effect of the TG value at separation points on the kinetic parameters is studied by residual and theoretical analysis. Simultaneously, a new method to determine the point that is the end of 1st reaction or the initial of 2nd reaction is developed. The investigations have improved the calculation procedure of PBSM. We performed thermogravimetry (TG) analysis on oil tea wood with two-step consecutive model and parallel model. Comparison between the results of the two models and improved PBSM shows well agreements. The influence of different separation points on kinetic parameters is presented.     

GABA受体抑制剂的柔性原子受体模型研究

利用Flarm软件为GABA受体抑制剂建立了其抑制家蝇和大鼠GABA受体的柔性原子受体模型， 很好地模拟了两种受体与药物分子结合的情况，具有较好的预测能力，预测集的预测值与实验值的相关系数（r2）分别达到0.923和0.733，模型的结果与药效团模型有很大的一致性，为揭示药物与两种受体作用的区别提供了依据.     

Kinetic and thermodynamic studies on the adsorption behavior of Rhodamine B dye on Duolite C-20 resin

The adsorption behavior of Rhodamine B dye from aqueous solutions was investigated onto the cation-exchange resin, Duolite C-20 (hydrogen form). The effects of various experimental factors; sorbent amount, contact time, dye concentration and temperature, were studied by using the batch technique. Lagergren pseudo-first-order equation shows good applicability with high correlation coefficients for all ranges of initial dye concentrations and at different temperatures. This equation was used to describe the kinetics of the dye adsorption process. The adsorption constants were evaluated by using both the Langmuir and Freundlich adsorption isotherm models. Thermodynamic parameters were obtained and it was found that the adsorption of Rhodamine B dye onto Duolite C-20 resin was an endothermic and spontaneous process at the temperatures under investigation.     

Memory effect of activated Mg-Al hydrotalcite: in situ XRD studies during decomposition and gas-phase reconstruction

The thermal decomposition of Mg-Al hydrotalcite and the subsequent reconstruction of the decomposed products in the presence of water vapor (2 vol. % H(2)O in N(2)) have been investigated by in situ XRD. Thermographic analysis and temperature-programmed desorption MS results complemented the diffraction data. Valuable mechanistic and kinetic insights into these processes, which are of prime importance for optimal activation of this type of material for catalytic applications, were obtained. Hydrotalcite decomposition to the mixed oxide proceeds via formation at 423-473 K of an intermediate phase, consisting of a highly disordered, dehydrated, layered structure. The latter evolves by removal of interlayer water on heating, causing a shrinking of the interlayer space (it is up to 45 % smaller than in the as-synthesized hydrotalcite). Above 623 K, Mg(Al)O(x) oxide with the periclase structure is formed. Reversion of the intermediate dehydrated structure to hydrotalcite upon contact with water vapor is complete and very fast at room temperature. Recovery of hydrotalcite from the oxide calcined at 723 K is two orders of magnitude slower than rehydration of the intermediate layered structure and one order of magnitude slower than the typically practiced liquid-phase reconstruction. In contrast to the decomposition, the reconstruction mechanism does not involve an intermediate phase. The gas-phase rehydration and reconstruction was interrupted above 303 K. This is attributed to the poor wetting of the surface of the decomposed materials induced by hampered H(2)O adsorption above room temperature at the water vapor pressure applied. The Avrami-Erofe'ev model describes the reconstruction kinetics well.     

基于遗传算法的PTP1B抑制剂的二维定量构效关系研究

利用遗传算法,并结合线性回归和交叉验证方法,对一系列43个苯并呋喃/噻吩联二苯类PTP1B抑制剂作了二维定量构效关系的研究.计算得到了一组效果较好的定量构效关系模型.模型不仅具有好的回归能力,而且还具有很好的预测能力.同时,通过分析在遗传优化过程中参数在精华种群中所占的比例,还得到了可能对活性影响较大的成分.计算结果表明,分子的4个参数:lgP(分配系数)、Area（表面积）、MW（分子量）以及Dip（偶极距）是影响化合物活性的最重要的参数,这对抑制剂的设计和改造提供了指导.     

Chemical Reconstruction of Pt-Rh(100) Alloy and Pt/Rh(100), Rh/Pt(100) Bimetallic Surfaces

When Cu(110), Ni(l 10), Ag(110) surfaces are exposed to O₂ at room temperature, one dimensional metal-oxygen strings grow in the < 001 > direction of the (110) surfaces. A similar phenomenon occurs in the adsorption of H₂ on Ni( 110) surface at room temperature, where the one dimensional strings grow along the < 110 > direction. These phenomena are undoubtedly different from the adsorption induced reconstruction but are explained by the chemical reconstruction involving the formation of quasi-compounds and their self-ordering on the metal surfaces. The chemical reconstruction is indispensablly important to understand the structure and catalysis of alloy and bimetallic surfaces. Pt_0.25Rh_0.75(100) alloy surface being active for the reaction of NO with H₂ is an interesting example. When the Pt-Rh(100) alloy surface is exposed to NO or O₂ at arround 500 K, a p(3 × 1) ordered Rh-O over-layer is obtained on a Pt-enriched 2nd layer by the chemical reconstruction. Ordering of Rh-0 in the p(3 × 1) structure on the Pt(100) surface was reproduced by heating a Rh/Pt(100) bimetallic surface in O₂, and the chemical reconstruction making the p(3 × 1) Rh-O overlayer on a Pt enriched 2nd layer was also proved by heating a Pt/Rh(100) bimetallic surface in O₂ or NO. The activation mechanism of the Pt-Rh alloy and the Pt/Rh bimetallic surfaces by the chemical reconstruction was evidently shown by using a Pt deposited Rh(100), Pt/Rh(100), surface. That is, the Pt/Rh(100) is not so active for the reaction of NO with H₂, but the reconstructed p(3 × 1)Rh-O/Pt-layer/Rh(100) surface is very active for the reaction. Therefore, it was concluded that the chemical reconstruction of the Pt-Rh catalyst makes the active surface which is composed of Rh-O and a Pt layer.     

STM vizualization of thiol-containing peptide dendrimers on Au(111)

Peptide dendrimers assembled by solid-phase peptide synthesis using a branching diamino acid at every 2(nd) or 3(rd) position provide readily accessible synthetic model systems for proteins and enzymes. They adopt a globular shape by topology rather than by folding. Peptide dendrimers of 2(nd) and 3(rd) generation functionalized with a cysteine or cystine residue in the core were adsorbed on Au(111) surface and imaged by STM at air, under UHV, or in solution. The dendrimers appear as globular features with dimensions suggesting an extended flattened conformation, forming both single globules and ordered arrays on the surface. These images represent the first direct visualization of peptide dendrimer enzyme models.     

重水溶液中稀土-吡啶-2,6-二羧酸配合物的第二配位圈^1HNMR顺磁位移

对稀土-吡啶-2,6-二羧酸(DPA)配合物Ln(DPA)3进行了NMR研究并观察到了由溶剂分子形成的第二配位圈的顺磁位移效应.     

K-stabilized high-oxygen-coverage states on Rh(110): a low-pressure pathway to formation of surface oxide

Using scanning tunneling microscopy, low-energy electron diffraction, and X-ray photoelectron spectroscopy, we studied the evolution of the structure and chemical state of a Rh(110) surface, modified by K adlayers and exposed to high O2 doses at elevated temperatures. We find that oxygen coadsorption on the K-covered Rh(110) leads to massive reconstruction of the Rh(110) surface. Stable reconstructed (10 x 2) and (8 x 2) segmented phases with a local coverage of more than two oxygen atoms per surface Rh atom were observed. Formation of surface oxide, which coexists with the (10 x 2) and (8 x 2) segmented adsorption phases, is evidenced at the highest O2 doses. The development of strongly reconstructed adsorption phases with oxide-like stoichiometry and surface oxide under UHV conditions is explained in terms of the stabilization of the (1 x 2) reconstruction and promotion of O2 dissociation by the K adatoms.