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1.
从协调人和自然关系及人民体质建设的宏观角度,探讨了环境元素与生命健康关系及其规律的方法论和解决问题的途径。明确元素存在的普遍性、内外环境元素的相关性,提出了生命元素周期变化节律及内、外环境元素整体动态的相对平衡和纵横向相对稳定的比例关系是保证生命健康的基础等概念。强调系统研究元素生物效应的重要性和人类活动在扩大元素三维分布不均匀性和增加元素与健康问题复杂性中的作用,由此提出了通过生物地球化学食物链系统研究和解决环境元素与生命健康关系问题是协调人与自然关系进行人民体质建设的重要途径。  相似文献   

2.
一、前言在生物体内,金属离子参与许多重要的生命过程,多种金属(如Fe、Cu、Co、Mo、Zn、Ca、Mg、K、Na等)离子是维持生命活动所必不可少的。许多与金属离子有关的生命过程  相似文献   

3.
混配化合物M(α-AP)2(OAc)2(M=Ni、Zn)的室温固相合成及表征   总被引:1,自引:0,他引:1  
Zn、Ni是重要的生命元素,在人体中属于必需的微量营养元素;金属离子与不同氨基酸形成的混配化合物,在生命活动中具有十分重要的作用,氨基酸中参与配位的主要是氮和羧酸,所以研究含氮和羧酸的混配化合物具有重要意义[1-6].  相似文献   

4.
金属离子对金属蛋白结构与功能的调控   总被引:1,自引:0,他引:1  
生命金属在生命过程中以不同的化学方式发挥着重要的作用。质膜、细胞器膜等使不同的生命金属在生物体系中有着不同的隔室化分布,相应的金属蛋白或金属伴侣蛋白在维持金属离子内稳态(homeostasis)中起着关键作用。生命体系中广泛存在着具有两个以上金属离子结合部位的金属蛋白。在确定的生理微环境下,由于金属离子结合热力学性质的不等价,该类金属蛋白的生物学功能取决于所结合金属离子的种类及多少。本文以伴刀豆球蛋白A、铜/锌超氧化物歧化酶、中心蛋白、锌指蛋白为例,介绍了金属离子在调控金属蛋白生物学功能中的作用。因此,深入研究金属离子与金属蛋白结合的热力学性质对于理解生命过程的无机化学基础具有重要意义。  相似文献   

5.
锌是重要的生命元素.在生物体内锌以多种形式参与代谢过程,包括糖类、脂类、蛋白质与核酸的合成与降解.对生命体系有着特殊的生物活性和催化作用。模拟合成以锌、铜等为中心离子的配位聚合物并对其结构进行研究.将为人们认识生命体系中与这些金属离子相关的生命现象提供重要的信息。4,4’-联吡啶是一种线状双基刚性配体.无支链,空间位阻少,有较好的桥联作用,  相似文献   

6.
金属离子对蛋白质的折叠、识别、自组装及功能的影响*   总被引:3,自引:0,他引:3  
蒋明  沈涛  徐辉碧  刘长林 《化学进展》2002,14(4):263-272
金属离子不仅影响金属蛋白的空间结构,还与生物大分子的识别、自组装等性质和生物功能密切相关。在很多蛋白质中,金属离子及其配合物可以诱导周围的肽段折叠成正确的结构,我们将其称为金属结合部位作为模板诱导的结构基序(Template-mediated structural motif,TMSM)。深入研究金属离子在蛋白质-核酸自组装体系中生物大分子交联及聚集体中的作用,对理解生命的无机化学基础具有重要意义。  相似文献   

7.
锌是重要的生命元素,在生物体内锌以多种形式参与代谢过程,包括糖类、脂类、蛋白质与核酸的合成与降解,对生命体系有着特殊的生物活性和催化作用[1].模拟合成以锌、铜等为中心离子的配位聚合物并对其结构进行研究,将为人们认识生命体系中与这些金属离子相关的生命现象提供重要的信息[2,3].4,4′-联吡啶是一种线状双基刚性配体,无支链,空间位阻少,有较好的桥联作用,它与金属离子在自组装过程中能形成各种一维,二维,及三维空间结构的配位聚合物[4~7].  相似文献   

8.
金属在生物和医学中的作用   总被引:20,自引:0,他引:20  
孙红哲  陈嵘  支志明 《化学进展》2002,14(4):257-262
金属元素在整个生命体系中起着重要的作用。金属离子与核酸、蛋白质等生物大分子的作用以及对神经系统的不正常的影响可以直接或间接地损伤DNA从而引起细胞的变异,进而导致各种疾病;同时我们可以根据这些特性研究金属离子的药物用于各种疾病的诊断和治疗。本文着重介绍了几种重要的金属和无机药物。  相似文献   

9.
蛇毒蛋白质中金属离子及其配位化学的研究刘清亮吴双顶张祖德余华明(中国科学技术大学应用化学系安徽合肥230026)在生命体内,金属离子能参与许多重要的生物化学反应,其实质就是金属离子与生物大分子的相互作用。蛇毒可以用作药物,具有抗凝、止血、抗癌和镇痛等...  相似文献   

10.
我国生物无机化学的发展   总被引:4,自引:0,他引:4  
杨频 《化学通报》1999,(12):1-11
叙述了生物无机在我国的发展。着重从金属离子及其配合物与生物大分子的作用、药物中的金属及抗癌活性配合物的作用机理、稀土元素生物无机化学、金属离子与细胞的作用、金属蛋白与金属酶、生物矿化、环境生物无机化学等七个方面综述了我国已取得的进展和成绩。  相似文献   

11.
A variety of silica‐based solid phases, whose surfaces are functionalized with ligands containing sulfur and nitrogen elements, are used as self‐supporting adsorbents for environmental remediation evaluation and potential separation application. Each adsorbent is tested for its ability to scavenge five metallic ions: Hg2+, Cu2+, Cd2+, Mn2+, Pb2+, and two organometallic ions: ethylmercury and phenylmercury, from independent homoionic solutions at both neutral and acidic pH values. The results indicate that the percentage of these ions scavenged by a given adsorbent varies, and is found to be highly related to the structural environment in the vicinity of the sulfur and nitrogen elements on the ligand. It is believed that the scavenging of metallic ions is a result of the complexation formation between the metallic ions and the ligands containing sulfur and nitrogen elements, and is not due to the irreversible association chemistry with the sulfur or nitrogen element itself. In the case of organometallic ions, a π‐π interaction is thought to be involved in the adsorption with ligands containing an aromatic moiety in addition to the aforementioned forces. The time needed to reach the maximum percent of adsorption decreases as the amount of adsorbent increases. The longer the adsorption time, the higher percent of ion is removed. Other factors, such as the temperature and the acidity in the liquid phase of the matrix affect the percentage of ions scavenged as well.  相似文献   

12.
The role of metallic matrix modifiers in AAS is considered; for elements reduced, together with modifier elements, during ashing and the beginning of the atomization process, the thermodynamic activity and melting points of the alloys formed are important. For Mg2+, prevention of the effects of halide ions is considered, as is also the behaviour of buffer and/or carrier in emission spectrometric analysis of the other alkali and alkaline earths.  相似文献   

13.
铝,镁,锌—氟哌酸配合物的荧光特性及其脂溶性研究   总被引:1,自引:0,他引:1  
探讨了介质PH值及Al^3-,Mg^2+,Zn^2+离子对喹诺酮类药物氟哌酸荧光特性的影响。发现铝,镁及锌离子在不同PH值条件下与氟哌酸形成配合物而增强荧光,据此建立了用铝离子增强荧光测定氟哌酸含量的新方法。  相似文献   

14.
Density functional calculations have been performed to investigate the destruction of narrow carbon nanotubes (CNTs) under the attack of nitronium tetrafluoroborate salts. The dissociation of these salts in a solvent produces nitronium and tetrafluoroborate ions which coadsorb on the external surface of the tubes. It is shown that the ions bind strongly to both metallic and semiconducting narrow nanotubes, although stronger to the metallic ones. The nitronium cations bind to the CNTs through a charge transfer mechanism, whereas the tetrafluoroborate anions remain negatively charged upon adsorption on the nanotubes. The surface of the nanotubes gets substantially deformed around the adsorption site of the nitronium ion, but it is hardly changed around the adsorption site of the tetrafluoroborate ion. These results are the theoretical basis to explain the destruction of the narrow CNTs found in the experiments and also to unravel, in agreement with the experimental interpretation, the distinct role played by the nitronium and the tetrafluoroborate ions. The tetrafluoroborate ions contribute to separate the CNTs from the bundles into individual tubes, without affecting the tubes. The nitronium ions, in contrast, modify the electronic and geometrical structures of the narrow tubes leading eventually to their destruction. The implications for the selective removal of intermediate diameter metallic CNTs found in the experiments are also discussed. The adsorption of the neutral nitrogen dioxide molecule is also studied, and the results show that the weak interactions of this molecule with both metallic and semiconducting tubes cannot be used as a model for the strong attack of the nitronium ions to the narrow tubes. The sensor effect of the nanotubes toward adsorption of nitrogen dioxide is also discussed.  相似文献   

15.
三价金属离子(Cr~(3+)、Fe~(3+)和Al~(3+))与人体健康密切相关。目前,检测Cr~(3+)、Fe~(3+)和Al~(3+)需要采用不同的荧光探针,增加了检测成本和检测时间。发展能够同时检测Cr~(3+)、Fe~(3+)和Al~(3+)的高灵敏度和强抗干扰能力的荧光探针具有非常重要的意义。本文以罗丹明B为原料,合成和表征了一种罗丹明类荧光增强型探针(P),并研究了其光谱性质。研究表明,在V(甲醇)∶V(水)=9∶1体系中对三价金属离子Fe~(3+)、Cr~(3+)和Al~(3+)具有较高的选择性,不受其它二价金属离子及一价金属离子的影响,抗干扰能力强。同时,探针P对三价金属离子具有较高的灵敏度,对Cr~(3+)、Al~(3+)和Fe~(3+)的检测限分别为3.0×10~(-4)、2.7×10~(-4)和1.0×10~(-4)mol/L,表明其可用于Cr~(3+)、Al~(3+)和Fe~(3+)的检测。  相似文献   

16.
The role of Cu/II/ and Co/II/ ions in the preparation of sodium123I-o-iodohippurate /Hippuran/ was investigated. It was found that Cu/II/ ions insure the highest radioactive labelling yield /97.61±0.92%/; while Co/II/ ions decrease the labelling yield. The role of Cu/II/ ions does not, however, appear to be catalytic in nature since in the absence of any metallic ion, the labelling yield was /95.00±1.01%/.Presented at the 9th Symposium on the Biological Aspects of Saudi Arabia held on 24–27 March 1986 in Riyadh, Saudi Arabia.  相似文献   

17.
In a previous work we studied the separation of cesium from a lanthanum target bombarded by protons in the thermoionic ion source of an electromagnetic isotope separator. After irradiation the principal elements found in the targets were Cs, Ba, Ce and La. We have extended this method to the separation of cesium and barium from metallic lanthanum targets and from lanthanum oxides. It is based on the thermoionization efficiency and on the behaviour of the element studied in the heated cavity, which depends on its volatility if it is under metallic form, and on its reduction and on the volatility of resulting compounds if it is under compound form. In the metallic system we obtained on the collector successively cesium and barium with respective overall yields of about 5% and 0.2%. In the oxide system, we obtained cesium as Cs+ ions and simultaneously barium as BaO+ ions which are separated from Ba+ by 16 masses avoiding the interference with cesium isotopes. The overall yield of the barium separation is about 0.2%. A discussion on the value of barium ionization potential is given.   相似文献   

18.
The graphene oxides (GOs) with various content of metallic ions impurities were prepared, and the adsorption performance of the GO before and after elution was evaluated. The prepared GOs were characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma and atomic force microscopy. The results indicated that the metallic ion impurities hardly affected the interlayer distance, microstructure and thickness of the prepared GOs. The adsorption isotherm and adsorption kinetic results showed that the metallic ions adsorbed on the GO surface had a negative influence on both the adsorption capacity and rate. After eluted by HNO3 or HCl, most of the metallic ions adsorbed on the GO‐91 surface were ion‐exchanged by the protons of the acid eluents, and the purified GO showed enhanced equilibrium capacities and improved adsorption rate. The elution efficiency of HCl was better than that of HNO3, and the adsorption capacity and rate of the GO eluted by HCl approximately reached to those of the GO prepared from the graphite with high purity. It indicated that HCl could efficiently remove the metallic ions adsorbed on the GO surface. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

19.
A first-principles Density Functional Theory study of several layered solids structurally related to rhombohedral arsenic has been carried out. The electronic structures of rhombohedral arsenic, CaSi(2), CaAl(2)Si(2), KSnSb, and SrSn(2)As(2) are discussed in detail, emphasizing on the origins of their metallic or nonmetallic behaviours. It is found that all of these systems are metallic except KSnSb. Electronegativity differences between the elements in the anionic sublattice and/or direct interlayer interactions play the main role in controlling the conductivity behavior. CaSi(2) exhibits a peculiar feature since the cation directly influences the conductivity but is not essential for its appearance. Cation-anion interactions are shown to have an important covalent contribution, but despite this fact and the metallic character found for most of these phases, the Zintl approach still provides a valid approximation to their electronic structure.  相似文献   

20.
The direct, reversible electrochemistry of horse-heart cytochrome c (cyt. c) was realized on a self-assembled glutathione (GSH) monolayer modified Au electrode. The voltammetric responses of cyt. c on GSH/Au electrode were found to be affected by pH during the electrode modification, metal ions and surfactants. Using potassium ferricyanide [K4Fe(CN)6] as a probe, these effects on the voltammetric responses of cyt. c were characterized by electrochemical methods. It was found that the pH during the electrode modification, metallic ions and surfactants changed GSH monolayer's charge state and the conformation on the electrode surface, and resulted in the influence on the voltammetric responses of cyt. c. The experimental results provided us information to understand the mechanism of the interfacial electron transfer of electrode-protein, as well as the electron transfer of cyt. c in life system.  相似文献   

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