一种钙/钙调蛋白依赖性的蛇毒磷脂酶A_2

分别研究了钙离子和三价稀土离子对白眉蝮蛇 (Agkistrodon blomhoffii Ussurensis)蛇毒磷脂酶 A2(PLA2 )活性的影响以及钙调蛋白对它的激活作用 .实验结果表明 ,PLA2 的活性对钙离子表现出依赖性 ,钙调蛋白能够激活该蛇毒 PLA2 ,钙调蛋白的拮抗剂三氟甲基吩噻嗪 (Trifluoperazine)能够完全抑制它对 PLA2的激活作用 .三价稀土离子 La3 、Eu3 、Dy3 、Yb3 对该 PLA2 的活性表现出抑制作用 ,其中离子半径较大的La3 和 Eu3 对酶活的抑制程度要小于半径较小的 Dy3 和 Yb3 .     

异维A酸二茂铁基衍生物的合成及其细胞毒活性的研究

为降低异维A酸的毒副作用并提高其癌细胞毒活性以及增加其在生物体内的吸收, 通过Mitsunobu反应, 以高于80%的收率合成了8种新异维A酸二茂铁基衍生物, 并进行了结构表征与确认. 采用3-(4,5-二甲基噻唑-2)-2,5-二苯基四唑溴盐(MTT)法测试了它们对肺癌细胞(A549)等的癌细胞毒活性. 结果显示, 引入二茂铁基团后的异维A酸二茂铁基衍生物具有很好的癌细胞毒活性.     

某些氨羧络合型染料与蛋白质相互作用的共振瑞利散射研究

用共振瑞利散射(RRS)光谱法研究了酚酞络合剂、百里酚酞络合剂以及钙黄绿素等氨羧络合型染料与人血清白蛋白(HSA)、牛血清白蛋白(BSA)、α-糜蛋白(α-Chy)、卵白蛋白(Ova)、溶菌酶(Lys)等水溶性蛋白质的相互作用,发现只有作为氨羧络合剂咕吨染料的钙黄绿素与蛋白质反应能使RRS显著增强,并观察到特征的RRS光谱,而作为氨羧络合型三苯甲烷的酚酞络合剂、百里酚酞络合剂作用不明显.文中对于钙黄绿素与蛋白质的反应条件、影响因素、反应产物的光谱特征及有关分析化学性质进行了研究,并拟定了用钙黄绿素RRS测定水溶性蛋白质的方法.该方法有高的灵敏度(对不同蛋白质的检出限在4.0～40.0 ng·mL^-1之间)和较好的选择性,可用于人血清中蛋白质的测定.     

胜利褐煤焦钙催化水蒸气气化反应中活性微结构分析

针对胜利褐煤焦水蒸气气化反应过程中钙组分的催化作用,在脱除矿物质胜利褐煤煤样SL~+中添加CaO在1 100℃热解得到添钙煤焦样品Ca-J,Ca-J经盐酸处理脱除其游离钙组分,得到添钙焦酸洗煤样Ca-J~+,采用BET、SEM-EDS、XRD、FT-IR及XPS等技术对所制备煤样进行表征,并在微型固定床反应装置上进行水蒸气气化反应性测试,对煤样微结构特性进行研究,提出了钙催化水蒸气气化反应中的活性微结构模型。结果表明,水蒸气气化反应中,添钙焦样酸洗前后的Ca-J和CaJ~+碳转化率及反应活性指数基本相同,但比酸洗煤焦样SL~+-J高出许多。样品XPS的Ca2p谱图分峰说明,Ca-J~+中存在Ca(CH_3COO)_2与Ca-OOR两种化学形态的钙。化学分析及SEM-EDS表征均表明,Ca-J~+中钙含量比Ca-J减少了97%以上;XRD表明,Ca-J中游离存在的CaS、CaO经酸洗被脱除;FT-IR表明,Ca-J及Ca-J~+中含有C=O、C-O等特征吸收峰。综合上述结果,可推测"R-O-Ca-O-R'"(R及R'可为脂肪族或芳香族结构体)是钙组分催化胜利褐煤焦水蒸气气化的活性微结构。     

青藏高原及邻区富碱侵入岩——以苦干子和太和二岩体为例

根据暗色造岩矿物、岩石化学成分和微量元素等,将本区富碱侵入岩分为2个系列:(1)钠质碱性系列岩石,为含碱性暗色矿物(霓辉石、霓石、钠闪石)碱性岩和碱性花岗岩,岩石化学成分富碱、富钠和贫钙以及Sr,Ba丰度低;(2)钾质碱性系列岩石,为含非碱性暗色矿物(透辉石、浅闪石)碱性岩和碱性花岗岩,岩石化学成分富碱、高钾和富钙以及Sr,Ba丰度高。     

铈对三角帆蚌钙代谢影响的研究

研究了不同浓度稀土Ce3+(0,0.5,1.0,2.5 mg·L-1)处理30,60 d时对2龄植片三角帆蚌钙代谢和珍珠质沉积的影响。结果表明:Ce3+对三角帆蚌珍珠质沉积量、外套膜和鳃组织中组织钙含量、钙调蛋白基因mRNA的表达量、腺苷三磷酸酶(ATPase)活性、碱性磷酸酶(ALP)活性的影响总体上均表现出明显的"低促高抑"的剂量效应和高浓度下"先促后抑"的时间效应。推测稀土Ce3+对钙调蛋白基因mRNA表达水平及关键酶活性的调节可能是其影响三角帆蚌钙代谢和珍珠质沉积的途径之一。     

改性柑橘果胶的制备、表征及抗癌活性

采用琼脂糖凝胶电泳、比旋度测试、HPSEC-RID、IR、¹H NMR、¹³C NMR、高碘酸氧化及甲基化分析等手段对改性柑橘果胶(MCP)进行了分析, 结果表明, MCP是一种均一性多糖, 分子量约为21000~66000, 糖醛酸质量分数为81.0%, 酯化度为2.13%. MCP的中性单糖残基主要包括鼠李糖(Rha)、阿拉伯糖(Ara)、木糖(Xyl)和半乳糖(Gal)等, 其摩尔比约为1.0∶1.5∶1.4∶1.3, 主链包括HG和RG, 分支结构含有末端Gal, Xyl和Ara. 选用3种小鼠移植性肿瘤模型对MCP的抗肿瘤生长活性进行研究. 结果表明, MCP对肝癌H22细胞有较强抑制作用, 高剂量下抑制率可达47.8%; 对宫颈癌U14细胞的抑制率在高剂量及中等剂量下分别达到36.5%和38.5%; 对肉瘤S180没有抑制活性. MCP的抗肝癌和抗宫颈癌活性为首次发现.     

枸橼酸二乙酯、枸橼酸钠和膦甲酸钠对高钙诱导小鼠血管平滑肌细胞钙化的抑制（英文）

在高钙及不同浓度枸橼酸二乙酯(Et_2Cit)、枸橼酸钠(Na_3Cit)和膦甲酸钠(PFA)存在下培养小鼠血管平滑肌细胞(MOVAS)14 d,分别通过茜素红染色、免疫荧光和annexin V染色检测细胞的分化、凋亡和细胞钙沉积量,研究了Et_2Cit、Na_3Cit和PFA对高钙诱导MOVAS细胞钙化的抑制效果及可能的作用机制。结果表明,Et_2Cit、Na_3Cit和PFA均能减少高钙诱导的MOVAS钙化,减少细胞外钙化斑块和钙沉积量。这些抑制剂均能抑制平滑肌细胞向成骨样细胞表型转化,导致向成骨细胞转化的标记物碱性磷酸酶(ALP)活性降低。抑制效果均存在浓度依赖性。当抑制剂浓度相同时,其抑制效果从大到小为:PFANa_3CitEt_2Cit。低浓度的Et_2Cit和Na_3Cit可通过减少细胞凋亡来抑制钙化,但高浓度的Et_2Cit、Na_3Cit和PFA自身具有毒性,这增加了细胞的凋亡。作为血液抗凝剂的Et_2Cit和Na_3Cit可以有效地抑制MOVAS的钙化。     

几种螯合剂解镍致小鼠胰脏毒作用比较

小鼠腹腔注射氯化镍溶液(5 mg Ni/kg)染毒，观察了N-苯甲基-D-葡糖氨基二硫代甲酸钠(BGD)、二乙氨基二硫代甲酸钠(DDTC)、二羟乙氨基二硫代甲酸钠(DHED)及meso-2，3-二巯基丁二酸钠(DMSA)等螯合剂对镍致小鼠胰脏毒性的解毒作用。镍染毒后引起小鼠胰脏胰蛋白酶活性升高和羧肽酶A活性降低以及组织中镍、钙、锌浓度增加；镍染毒30 min和24 h后进行各螯合剂治疗(剂量均为400 μmol/kg)，BGD、DDTC和DMSA可明显抑制上述变化，其中BGD解镍毒效果最好、自身毒性最小、对镍致小鼠胰脏毒性有更好的解毒作用。     

A位缺陷对La-Sr-Co-O钙钛矿结构和催化氧化性能的影响

采用柠檬酸络合法制备La-Sr-Co-O钙钛矿, 通过酸处理溶解Sr离子, 得到了相应的A位缺陷钙钛矿. 采用X射线衍射(XRD)、 X射线吸收精细结构(XAFS)、 电感耦合等离子体原子发射光谱(ICP-OES)、 X 射线光电子能谱(XPS)和拉曼光谱(Raman)等表征技术考察了A位缺陷钙钛矿的晶体结构、 配位环境及表面电子结构等性质, 通过CO氧化和NO氧化活性测试评价了A位缺陷钙钛矿的催化性能. 结果表明, 简单酸处理有选择性地改造了Sr富集区, 溶解了SrCO₃ 以及大部分SrO. 钙钛矿主体结构基本不变, 局域结构中Sr(A位)的缺位造成Co离子以Co₃O₄形式溶出, 并形成了更多的氧缺陷, 有效地活化了晶格氧物种, 因此其在CO氧化和NO氧化反应中均表现出更优异的低温活性.     

Styrene epoxidation with hydrogen peroxide over calcium oxide catalysts prepared from various precursors

A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry(TG),X-ray diffraction(XRD),scanning electron microscopy(SEM),N2-adsorption and temperature-programmed desorption of CO2(CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.     

鼓风炉渣中氧化钙的测定方法改进

在参照DHF83-B多元素快速分析仪法测定炉渣中氧化钙的基础上,对鼓风炉渣中氧化钙的测定方法进行了改进。用盐酸（1+1）溶样,三乙醇胺掩蔽残留的铁、铝、锰等元素,以钙指示剂作指示剂,于pH值大于12时用EDTA标准溶液滴定氧化钙。EDTA滴定法分析结果的相对标准偏差RSD为2.82%,与DHF83-B多元素快速分析仪法比较,其结果基本一致。该方法具有准确度好、快速简便等优点,适合用于冶炼炉渣中氧化钙含量的测定。     

Controlling the cohesion of cement paste

The main source of cohesion in cement paste is the nanoparticles of calcium silicate hydrate (C-S-H), which are formed upon the dissolution of the original tricalcium silicate (C(3)S). The interaction between highly charged C-S-H particles in the presence of divalent calcium counterions is strongly attractive because of ion-ion correlations and a negligible entropic repulsion. Traditional double-layer theory based on the Poisson-Boltzmann equation becomes qualitatively incorrect in these systems. Monte Carlo (MC) simulations in the framework of the primitive model of electrolyte solution is then an alternative, where ion-ion correlations are properly included. In addition to divalent calcium counterions, commercial Portland cement contains a variety of other ions (sodium, potassium, sulfate, etc.). The influence of high concentrations of these ionic additives as well as pH on the stability of the final concrete construction is investigated through MC simulations in a grand canonical ensemble. The results show that calcium ions have a strong physical affinity (in opposition to specific chemical adsorption) to the negatively charged silicate particles of interest (C-S-H, C(3)S). This gives concrete surprisingly robust properties, and the cement cohesion is unaffected by the addition of a large variety of additives provided that the calcium concentration and the C-S-H surface charge are high enough. This general phenomenon is also semiquantitatively reproduced from a simple analytical model. The simulations also predict that the affinity of divalent counterions for a highly and oppositely charged surface sometimes is high enough to cause a "charge reversal" of the apparent surface charge in agreement with electrophoretic measurements on both C(3)S and C-S-H particles.     

仿生矿化的机理和应用研究进展

碳酸钙、磷酸钙为代表的生物矿物广泛分布于自然界中,经过不同的矿化过程,在生物体内呈现出多样的结构、形貌和功能,构成生物体多种组织和器官.在人工材料合成领域,仿生矿化通过调控碳酸钙、磷酸钙等矿物的成核与生长,获得具有复杂高级结构和特殊生物功能的无机或无机/有机复合材料.本文重点介绍仿生矿化机理和应用的最近研究进展,包括仿...     

The hydraulic activity of high calcium fly ASH

Cementitious mixtures with so-called high calcium fly ash show better strength parameters as compared to the ones with conventional siliceous fly ash. This practical feature is the consequence of improved hydraulic activity. Differential thermal analysis and thermogravimetry were used, together with the other methods, to evaluate the reactivity of high calcium fly ash in mixtures with cements. This type of fly ash exhibits hydraulic properties (setting and hardening on hydration) and durability, after hardening, in the presence of water. The so-called pozzolanic activity is the feature of high active silica containing fly ash while the hydraulic activity is related to the high calcium ones. However, the chemical and phase composition is variable and related to the particle size. The hydraulic/ pozzolanic properties are strongly improved by additional grinding (specific surface increase).     

基于扫描探针显微镜（SPM）的高密度信息存储

随着信息技术的飞速发展,高密度信息存储的研究成为国际上备受关注的研究领域。扫描探针显微技术（SPM）通过改变材料的光、电、磁等局域特性可以实现纳米尺度的信息存储,成为提高信息存储密度的最有效手段之一。本文从信息存储材料和技术角度综述了基于SPM的高密度信息存储最近的研究进展,并讨论了其将来的研究和发展方向。     

CaP/壳聚糖复合膜层的电化学共沉积研究

用电化学共沉积方法在医用钛合金表面成功制备了CaP/壳聚糖复合膜层,并用XRD,SEM,FTIR漫反射光谱和XPS等对复合膜层化学组成及结构进行表征.结果表明,加入壳聚糖可使钙磷沉积层结构发生显著变化,将壳聚糖掺入钙磷沉积层,形成CaP/壳聚糖复合物和杂化物.力学实验表明,在钛基底表面未进行表面预处理条件下,CaP/壳聚糖复合膜层与钛基底的结合力高达2.6MPa,比单一CaP电化学沉积层与基底的结合力提高约4倍.文中还对壳聚糖参与表面电沉积反应机理进行了讨论.     

Anion Modulation of Pt-Group Metals and Electrocatalysis Applications

Pt-group metal (PGM) electrocatalysts with unique electronic structures and irreplaceable comprehensive properties play crucial roles in electrocatalysis. Anion engineering can create a series of PGM compounds (such as RuP₂, IrP₂, PtP₂, RuB₂, Ru₂B₃, RuS₂, etc.) that provide a promising prospect for improving the electrocatalytic performance and use of Pt-group noble metals. This review seeks the electrochemical activity origin of anion-modulated PGM compounds, and systematically analyzes and summarizes their synthetic strategies and energy-relevant applications in electrocatalysis. Orientation towards the sustainable development of nonfossil resources has stimulated a blossoming interest in the design of advanced electrocatalysts for clean energy conversion. The anion-modulated strategy for Pt-group metals (PGMs) by means of anion engineering possesses high flexibility to regulate the electronic structure, providing a promising prospect for constructing electrocatalysts with superior activity and stability to satisfy a future green electrochemical energy conversion system. Based on the previous work of our group and others, this review summarizes the up-to-date progress on anion-modulated PGM compounds (such as RuP₂, IrP₂, PtP₂, RuB₂, Ru₂B₃, RuS₂, etc.) in energy-related electrocatalysis from the origin of their activity and synthetic strategies to electrochemical applications including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR), N₂ reduction reaction (NRR), and CO₂ reduction reaction (CO₂RR). At the end, the key problems, countermeasures and future development orientations of anion-modulated PGM compounds toward electrocatalytic applications are proposed.     

Synthesis and antimicrobial activity of CuO@BaO/CaO nanocomposites using precipitation method

In this study, copper oxide doped barium and calcium oxide were prepared by a simple precipitation method. Using the similar synthetic procedure, to alter the molar radio of metal precursor to prepared four different composites viz., CuO@BaO/CaO (0.5:0.4:0.1), CuO@BaO/CaO (0.5:0.3:0.2), CuO@BaO/CaO (0.5:0.2:0.3) and CuO@BaO/CaO (0.5:0.1:0.4). The prepared composites were evaluating the X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), Scanning Electron Microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDAX) analysis. Antibacterial tests were carried out on the composite produced. The results show that the composite materials exhibit high antibacterial activity with CuO@BaO/CaO(0.5:0.3:0.2) exhibiting stronger activity than CuO@BaO/CaO (0.5:0.4:0.1) because barium concentration decreases and calcium concentration increases.     

服用柠檬酸钾前后草酸钙结石患者的尿微晶和尿液性质变化

采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶变换红外光谱(FTIR)和ζ电位分析仪研究了草酸钙(CaOxa)结石患者在服用柠檬酸钾(K3cit)前后尿液中微晶的性质变化,这些性质包括:尿微晶的形貌、尺寸、聚集状态、质量、种类和ζ电位,并研究了服药前后尿液的稳定性差异和pH值变化。服用K3cit前,结石患者的尿微晶棱角尖锐,聚集明显,尺寸从几十纳米到几百微米不等,主要为一水草酸钙(COM)、尿酸等;而服用K3cit一周后,部分尿微晶的形状变得圆钝,聚集现象明显减少,平均粒径减小,部分尿微晶的表面出现凹陷,二水草酸钙(COD)和尿酸盐的百分含量增加,尿微晶的数量和种类减少,尿液pH值上升,ζ电位绝对值增加,自相关时间增加。从患者服用K3cit后引起尿pH值增加、尿液中排泄的柠檬酸和Tamm-Horsfall蛋白浓度增加、柠檬酸与Ca2+离子配位等角度,讨论了K3cit抑制CaOxa结石形成的机制。