稀土发挥生物效应的机制及其作用物种探讨

稀土在工业、医药领域、基础研究以及在我国的广泛农用引起了人们对其生物效应机理以及可能毒性的关注.在稀土生物学效应机理及毒性的研究中,无论是在动物水平还是细胞层次,引起生物学效应的稀土物种都是一个关键问题,一直存在争议.本文对以动物、细胞为模型的生物效应研究中的实验条件进行分析,对生理条件下引起稀土生物学效应的可能物种提出"稀土离子池"(rare earth ion pool)模型,并对其引起生物学效应的活性物种以及与细胞膜相互作用的方式进行了探讨,以期为阐明复杂生物学体系中稀土化合物的作用机制提供思路.     

稀土药用研究的动向和问题

人们对稀土药用的兴趣普遍增加.最近Chemical Society Reviews在2006年第6期刊登了镧系元素药用研究专刊,专门介绍稀土药用研究的现状.针对该专刊和稀土药用研究的现状,作者讨论了稀土化合物药用研究的发展动向,特别讨论了需要解决的关键基础问题.从新药研究模式的转变得到启发,提出如何把负面生物效应转化为药理作用,如何从干预细胞信号网络入手进行研究,如何处理活性与毒副作用的关系,以及药物合理设计的策略等.     

稀土药用研究的动向和问题

人们对稀土药用的兴趣普遍增加。最近Chemical Society Reviews在2006年第6期刊登了镧系元素药用研究专刊,专门介绍稀土药用研究的现状。针对该专刊和稀土药用研究的现状,作者讨论了稀土化合物药用研究的发展动向,特别讨论了需要解决的关键基础问题。从新药研究模式的转变得到启发,提出如何把负面生物效应转化为药理作用,如何从干预细胞信号网络入手进行研究,如何处理活性与毒副作用的关系,以及药物合理设计的策略等。     

稀土药用研究的动向和问题

人们对稀土药用的兴趣普遍增加.最近Chemical Society Reviews在2006年第6期刊登了镧系元素药用研究专刊,专门介绍稀土药用研究的现状.针对该专刊和稀土药用研究的现状,作者讨论了稀土化合物药用研究的发展动向,特别讨论了需要解决的关键基础问题.从新药研究模式的转变得到启发,提出如何把负面生物效应转化为药理作用,如何从干预细胞信号网络入手进行研究,如何处理活性与毒副作用的关系,以及药物合理设计的策略等.     

量热法测定氯化钐与甘氨酸配合物的标准生成焓

稀土在生命科学领域的研究日益受到人们关注,稀土化合物所具有的抑菌、抑癌、消炎等作用及其作用机理的探讨已有报道［１～３］。最近几年稀土在生物领域中的研究又有了新的突破和进展,从稀土与氨基酸、蛋白质、膜脂及膜蛋白的作用到其对ＤＮＡ。ＲＮＡ的影响［１,４］,从稀土的分子水平、细胞及亚细胞水平到动物整体实验的系统研究［５,６］等,分别从不同的层次、不同的水平研究了稀土的生物效应。但至目前为止,稀土的生物效应机理及其对人体的影响尚未得到令人满意的解释。由于氨基酸是构成人体蛋白质的基本单位,故研究稀土与氨基…     

镧、铈对红豆杉细胞生长及紫杉醇合成与释放的影响

研究镧、铈对东北红豆杉悬浮细胞生长及紫杉醇合成与释放的影响。结果表明，当发酵液中稀土浓度较高时，均能明显改变东北红豆杉细胞的生长模式，使细胞生长的延迟期与对数期缩短，平稳期消失，并于衰亡期出现生物量的周期性振荡；在细胞生长的对数期加入稀土化合物能显著提高东北红豆杉细胞合成与释放紫杉醇的量；在加入稀土化合物的同时，补加碳源，有利于细胞合成紫杉醇。     

纳米Eu2O3和Eu3+对人肝细胞HL-7702生长的影响

稀土化合物的生物效应研究已引起人们的大量关注,但纳米稀土氧化物对细胞产生的生物效应报道较少.为了研究纳米稀土氧化物和稀土离子对正常细胞作用后的影响差异,采用MTT比色实验,形态观察和流式细胞术等方法探讨了纳米Eu2O3和Eu3+对体外培养的人肝细胞HL-7702生长的影响.结果发现,较低浓度的纳米Eu2O3对细胞生长没有明显影响,较高浓度(≥800μg·ml-1)的纳米Eu2O3作用肝细胞后,具有明显的毒性作用,出现了凋亡特征;而Eu3+在较低含量,即≤100 μmol·L-1时诱导肝细胞S期细胞比率上升,对肝细胞增殖有较弱的促进作用.     

稀土对大鼠尿液成分影响的核磁共振研究

目前,稀土生物效应的研究已进入了分子和细胞水平,但在活体动物内研究稀土的作用情况还不多见。稀土化合物随食物进入动物体内后,会对动物体内的器官、组织、细胞产生一定影响,将导致其体液容量、分布、电解质浓度等方面的变化。现代NMR技术是目前药理毒理学研究的有效手段之一,它具有简便、全面、快捷、非破坏性等优点,可用于对体液样品的检测和研究。本文采用现代核磁共振技术研究了稀土化合物硝酸镧灌胃给药后对Wistar大鼠尿液中代谢产物的影响,为阐明稀土化合物的毒理学机制和稀土的进一步开发利用提供理论依据。     

从钒化合物生物效应的多样性看其作用机制*

本文对近年来关于钒化合物不同生物效应机制的研究进展进行了总结,着重于其类胰岛素和抗癌效应的信号转导机制以及两者之间的相关性。同时,基于钒化合物对磷酸转移反应的干预以及对细胞氧化还原状态的调节,讨论了钒化合物多样化的生物效应是否具有一个共同作用机制的可能性,并提出了未来钒化合物研究方向和所面临的挑战。     

磷光寿命法研究稀土配合物的跨膜传输

从分子水平研究细胞与稀土离子及其配合物的作用机制和跨膜行为以及在细胞内作用的靶分子是阐明稀土生物效应的基础理论问题，研究这一问题对指导稀土的应用意义重大．要实现解决这一科学家梦寐以求的本质问题，关键是要寻求切实可行的有效的研究方法．室温磷光光谱分子探针技术在研究动物组织和细胞方面的应用发展非常迅速，由于氧在各种组织中分布的差异，因而对探针分子的磷光碎灭影响不同．曾经有人用把外吩配合物为磷光探针研究了细胞组织的病变行为’‘－‘’．本文选用的探针为稀土钦离子，通过测定稀土钦离子的磷光寿命，可以观察稀…     

Copper-Based Nanoparticles as Antibacterial Agents

Over the past few decades, the resistance of different pathogenic bacteria to various antibiotics has gradually increased. In order to solve the problems of this modern era, metal nanoparticles have attracted more attention than ever. Copper has been recognized as a non-toxic, safe inorganic material and cheap antibacterial or antifungal agent, showing potential antibacterial effect in many biomedical fields. This interest has accelerated the generation of many novel methods for the synthesis of copper-based nanoparticles. Due to the non-toxicity and safety requirements of antibacterial agents, the recent green synthesis of copper-based nanoparticles is gradually replacing the traditional methods. In addition, the antibacterial mechanism of copper-based nanoparticles has provoked great curiosity. This review summarizes the synthetic methods, the possible antibacterial mechanisms and applications of copper-based nanoparticles. Additionally, the application prospects of copper-based nanoparticle antibacterial agent in biomedical applications and clinical field have been described and discussed.     

动力型锂离子电池正极材料LiFePO4的改性研究

橄榄石型LiFePO4具有高的理论比容量、高倍率特性、优越的电化学和热稳定性能、循环寿命长且绿色环保等优点,被认为是新一代动力型锂离子电池理想的正极材料之一.LiFePO4因本身结构的缺陷导致了其极低的电导率和Li+扩散速率,限制了该材料在动力电池的中实际应用.本文综述了通过表面包覆修饰、金属阳离子晶体结构内掺杂和导电...     

Polymer-drug conjugates as inhalable drug delivery systems: A review

Accelerating interest by the pharmaceutical industry in the identification and development of less invasive routes of nanomedicine administration, coupled with defined efforts to improve the treatment of respiratory diseases through inhaled drug administration has fuelled growing interests in inhalable polymer-drug conjugates. Polymer-drug conjugates can alter the pharmacokinetic profile of the loaded drug after inhaled administration and enable the controlled and sustained exposure of the lungs to drugs when compared to the inhaled or oral administration of the drug alone. However, the major concern with the use of inhalable polymer-drug conjugates is their biocompatibility and long-term safety in the lungs, which is closely linked to lung retention times. A detailed understanding about the pharmacokinetics, lung disposition, clearance and safety of inhaled polymer-drug conjugates with significant translational potential is therefore required. This review therefore provides a comprehensive summary of the latest developments for several types of polymer-drug conjugates that are currently being explored as inhalable drug delivery systems. Finally, the current status and future perspective of the polymer-drug conjugates is also discussed with a focus on current knowledge gaps.     

Prussian blue analogues as aqueous Zn-ion batteries electrodes: Current challenges and future perspectives

The urgency of integrating renewable energy sources in the power grid has pushed the development of aqueous metal-ion batteries because of their low cost, nontoxicity, high safety, and environmentally friendliness. Among the variety of aqueous metal-ion batteries that are currently under development, aqueous Zn-ion batteries (A-ZIBs) have recently gained a great attention because of their high specific energy and high reversibility in aqueous solutions, together with the low cost and high abundancy of the zinc. In this article, the authors intend to present an overview of the Prussian blue analogue materials, which are among the most promising materials for positive electrodes in A-ZIBs because of their easier synthesis route, reversible ion-insertion, high safety, and low toxicity, highlighting their strength points and open challenges.     

A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant

A continuous-flow synthesis of primary amides from hydrolysis of nitriles using hydrogen peroxide as oxidant has been developed. Using this procedure, a variety of nitriles could be smoothly transformed into the desired primary amides in good to excellent yields. The mild reaction conditions and the flowing reaction system greatly improved the safety and make the reaction easy to scale up.     

Solvent extraction separation of rhodium(III) with N-n-octylaniline as an extractant

Solvent extraction separation method for the determination of rhodium(III) has been described. Selective and quantitative extraction of rhodium(III) by N-n-octylaniline, a high molecular weight amine (HMWA) into xylene takes place from aqueous sodium malonate medium. The effect of concentration of malonate, N-n-octylaniline, role of various diluents, stripping agents and foreign ions on the extraction of rhodium(III) has been studied. The procedure offers distinct improvements in need of real sample analysis and environmental safety as the extraction procedure carried out in weak organic acid media.     

Use of stable isotopes as surrogates for radionuclides for security studies

During the past decade, interest has increased in qualifying and quantifying the threat posed to the public by the illegal use of radionuclides. In order to take investigations beyond the laboratory bench into more realistic scenarios, environmental and safety considerations dictate that these studies be performed on stable and benign surrogates. This paper discusses some of these studies, specifically the use of cerium dioxide for actinide ceramics and calcium and natural strontium ceramics for those based on ⁹⁰Sr.     

化学实验室安全教育实效研究*——以大二学生为例

为考察化学实验室安全教育实效,本文对天津理工大学化学化工学院大二学生的实验室焦虑、安全态度、安全意识以及安全知识进行问卷调查。调查结果表明:实验室焦虑存在性别差异,女生焦虑情绪比男生严重;参加过安全教育培训学生比未参加安全培训学生安全态度更为端正。回归分析表明:实验室焦虑、安全态度和安全知识都与安全意图显著正相关。基于统计分析结果,提出以下安全培训提升策略:关注学生心理安全,加强情绪疏导,克服实验室焦虑;优化安全教育模式,发挥学生主观能动性,提高安全教育实效。最后,安全教育也是立德树人的过程,通过安全教育,将学生培养成为敬畏生命、敬畏责任、敬畏规章、具有正确安全道德价值观的化工行业从业人员。     

Ionic liquids as hypergolic fuels

In propellant systems, fuels of choice continue to be hydrazine and its derivatives, even though they comprise a class of acutely carcinogenic and toxic substances which exhibit rather high vapor pressures and require expensive handling procedures and costly safety precautions. Only recently (2008), ionic liquids (salts with melting points less than 100 °C) with the dicyanamide anion were shown to exhibit hypergolic properties (instantaneous ignition when contacted with oxidizers (100 % nitric acid, WFNA)). Such liquids tend to have low volatilities, and high thermal and chemical stabilities, and often exhibit long liquid ranges which could allow utilization of these substances as bipropellant fuels over a variety of conditions. A new family of dicyanoborates is presented, which can be synthesized in water, with substituted N‐acyclic, N‐cyclic, and azolium cations has met nearly all of the desired important criteria needed for well‐performing fuels.     

Improved Alkylation Technology with Solid Acid Material as Catalyst

Alkylation of isobutane with C3-C5 olefins has been practiced commercially since the 1940s. Indeed, alkylation which is mainly formed by multibranched paraffins,has a rather low vapor pressure, high octane numbers (RON and MON) and a low sensitive factor. In the past twelve years, about 20 alkylation plants using either HF or H₂SO₄ catalysts have been built in China^[1]. Concerns have been raised about the safety and environmental impact of the handing of the very large quantities of these liquid acids used in alkylation today and a great deal of time and money has been spent in the past 20 years in attempts to develop alkylation catalyst and process that are more environmentally friend than current industrial technology^[2]. To date,no process has been announced that seems to be of commercial interest, but two possible exceptions (Topöse process and UOP Alkylene process) are discussed in this paper. Many difficult technical challenges must be surmount in the next few years for a new solid catalyst alkylation process to be commercialized successfully.