色谱联用技术在环境和生物样品中痕量超痕量元素形态分析研究进展

随着分析科学的不断发展,常用的元素分析方法,如光谱技术(AES,AFS)和质谱等已不能满足环境和生物样品中痕量、超痕量元素的赋存形态分析。以色谱联用技术为代表的元素形态分析测试技术(如液相色谱-原子光谱联用、色谱-电感耦合等离子质谱联用、毛细管电泳-电喷雾离子化质谱联用技术等)已成为国内外研究的热点。本文扼要的介绍了近年来国内外在环境和生物样品中痕量、超痕量元素砷、硒、汞形态分析的色谱联用技术研究进展,并侧重于样品前处理方法、痕量或超痕量元素的形态分析技术。     

燃煤飞灰吸附脱汞能力的实验研究

运用煤岩学分类相关理论对燃煤飞灰岩相组成进行了系统定量分析,并采用固定床汞吸附反应系统对不同电厂飞灰吸附汞的能力进行了详细研究,结果表明:不同的飞灰对汞均有一定的吸附能力,其中以烟煤飞灰CTSR和CTL的富碳组分对汞的吸附能力最强,其吸附能力分别为10.3和9.36μg/g,与商业活性炭捕获能力相当;飞灰中汞的含量与其含炭量和比表面积并无明显的相关性.揭示了飞灰颗粒岩相组成,分析了飞灰脱汞能力的影响因素.不同飞灰碳颗粒类型脱汞性能差异明显,各向异性碳颗粒尤其是多孔网状结构碳含量是决定飞灰脱汞能力的主要因素.     

双硫腙接枝凝胶的制备及其除汞性能

以单聚体聚丙烯酰胺凝胶(PAGE)为基体,双硫腙为接枝基团制备了接枝凝胶。探究了接枝凝胶对含汞水体的除汞作用及其最适反应条件。结果表明,当pH:7、T=20℃、t=120 min、投料比为7g/L时,处理8 moL/L的模拟含汞废水,汞离子去除率可达99.5%,效果明显,除汞性能较聚丙烯酰胺凝胶得到显著优化。含汞水体中汞离子起始浓度越高,去除率虽随之降低,但单位质量凝胶捕获汞离子质量随之升高。同时,在阳离子干扰实验中,钙离子会对凝胶的除汞作用产生较强干扰,其他实验阳离子干扰作用却不明显。因此,可考虑将其用于含汞废水的处理。     

水中全氟化合物电化学去除技术研究进展

全氟化合物(perfluorinated compounds,PFCs)是一类人工合成的难降解有机污染物.PFCs长期大量使用导致其在水环境中普遍存在,并且已在人体中检出.传统的生物处理技术对PFCs几乎没有去除效果,研究高效去除水体中PFCs的实用化技术成为了环境领域的研究热点.本文综述了电化学氧化、电絮凝和电吸附等电化学技术在PFCs废水处理中的研究进展,详细阐述了不同电化学处理技术对PFCs的去除效率、影响因素以及去除机理,并对今后水体中PFCs电化学去除技术研究提出了展望.     

姜黄素诱导肝癌HepG2细胞凋亡及其对bcl-2及survivin蛋白表达的影响

目的 研究姜黄素对HepG2细胞凋亡的促进作用,并探讨其可能的的作用机制.方法 实验分为空白对照组、1 mg/ml、1.5mg/ml、2mg/ml的姜黄素处理组,MTT法检测不同浓度姜黄素对细胞增殖抑制情况;电镜观察细胞形态及其结构变化;流式细胞术检测凋亡率;Western blot检测各组作用24 h后细胞中bcl-...     

换能器焊点对声场分布影响的研究

在换能器设计和生产过程中,焊接点作为电声转换元件实现信号输入输出的接点,它的大小和位置不但会引起换能器的固有频率变化,也会引起换能器的振动变化,从而影响其辐射声波的声场分布。本文选择在聚焦超声换能器辐射面上的固定位置处,添加不同质量的锡丝,构成焊点;然后利用纹影法获取换能器声束聚焦的形态图像,以此分析焊点对声场分布的影响。多组实验表明,随着换能器配重的增加,引起的换能器振动分布越不均匀,其声束聚焦的形态偏离理想形态的程度越严重。     

基于城市设计的大尺度城市空间形态研究

在当今中国史无前例的城市化进程中,相当多的中国城市都不同程度地经历了城市规模的急剧扩张．伴随着城市规划的持续编制、修编和实施,城市的功能结构、空间环境、街廓肌理乃至社会等发生了显著的变化,而所有这些都直接发生在某一城市尺度、甚至是发生在某一城市的大尺度空间形态上．本文通过对城市空间形态构成、演进和外显表征的描述和分析,尝试建构城市形态影响要素模型,进而讨论与形态密切相关的城市用地属性及保护、调整和开发潜力．同时,基于城市设计参与良好城市空间形态塑造和建设管理的专业特征,提出针对大尺度城市空间形态的量化评析技术方法,从而为城市政府和规划建设管理部门提供技术支持．     

基于河流阻力规律的砂砾质河型分类方法研究

河流形态特征的变化规律是人类认识与改造河流的主要课题.河流系统分布广泛,与人类活动密切相关,了解其类型特点是河流研究中的重要内容.水流在其行进过程中遵守阻力规律,由于周围环境的不同,其宏观表现形式也多种多样.河流的阻力规律决定于其形态特征,同时河流形态特征也反映其阻力规律.本文考虑影响河流水力损失的多种因素,引入无量纲的河流形态参数,得到自然河流的阻力规律表达式.由该阻力规律出发,得到河流形态参数的表达式,并将其作为河型分类标准.本文还加入了地貌因素的影响,应用得到的表达式细致划分了河流类型.研究结果表明,该分类方法计算简单,对于砂砾质河流应用效果较好.     

远紫外宽带极光成像仪初步研究

在回顾星载远紫外波段极光形态探测技术发展的基础上, 介绍我们研制的用于极光形态探测的远紫外宽带极光成像仪, 该仪器研制目的是用于大椭圆轨道上对极光形态及其随时间变化进行连续观测, 为我国首次研制该类型仪器. 仪器主要由望远镜系统、像增强器系统、CCD及采集控制系统组成. 仪器工作波段在140~190 nm, 总视场25°×25°, 空间分辨率优于0.1°.     

碲镉汞红外探测器研究进展

基于碲镉汞材料体系,现代红外探测器技术进入体系化发展快车道,经过近六十年发展,碲镉汞红外探测器俨然成为高性能红外探测器的基线,已经完成三代迭代,正在开展第四代探索.近几十年来,锑化铟、量子阱、二类超晶格、量子点等材料体系对碲镉汞体系展开了全面竞争,至今仍未找到一种材料体系能够全面对标碲镉汞.昆明物理研究所独立完成国内第一代红外探测器研制生产、第二代红外探测器量产和第三代红外探测器工程化,中波、短波面阵规模达到2048×2048,双波段面阵规模达到640×512,甚长波后截止波长达到15μm以上,温度分辨能力达到3 m K,中波探测器工作温度达到150 K,接近国际先进水平.近年来,围绕新一代红外探测技术,昆明物理研究所提出以光子计数级极限灵敏度、多维信息全光感知为主要特征,以超越规模、超越像元、超越光伏为主要途径,以看得透、看的住、看得巧为主要目标的新一代红外探测技术具体内涵,推动红外光电探测应用更新换代.     

Trace metal requirements in total parenteral nutrition: A theoretical approach by mathematical modeling

Summary A new computer-based approach has been developed to assess the optimal doses of essential trace metal ions which should be included in nutritive mixtures, used in human total parenteral nutrition, to compensate for the ligand-induced losses of these metal ions. An example of application is given for zinc, copper and manganese.     

Aluminium in Alzheimer’s disease: are we still at a crossroad?

Aluminium, an environmentally abundant non-redox trivalent cation has long been implicated in the pathogenesis of Alzheimers disease (AD). However, the definite mechanism of aluminium toxicity in AD is not known. Evidence suggests that trace metal homeostasis plays a crucial role in the normal functioning of the brain, and any disturbance in it can exacerbate events associated with AD. The present paper reviews the scientific literature linking aluminium with AD. The focus is on aluminium levels in brain, region-specific and subcellular distribution, its relation to neurofibrillary tangles, amyloid beta, and other metals. A detailed mechanism of the role of aluminium in oxidative stress and cell death is highlighted. The importance of complex speciation chemistry of aluminium in relation to biology has been emphasized. The debatable role of aluminium in AD and the cross-talk between aluminium and genetic susceptibility are also discussed. Finally, it is concluded based on extensive literature that the neurotoxic effects of aluminium are beyond any doubt, and aluminium as a factor in AD cannot be discarded. However, whether aluminium is a sole factor in AD and whether it is a factor in all AD cases still needs to be understood.Received 22 July 2004; received after revision 3 September 2004; accepted 16 September 2004     

Effect of ascorbic acid on biotransformation and modification of the toxicity of mercurials in goldfish (Carassius auratus)

Summary Ascorbic acid mediated a small but significant degradation of methylmercury to inorganic mercury in goldfish (Carassius auratus) and reduced the toxicity of mercuric chloride despite its substantial conversion into organic form. This investigation was supported by a grant from the Fishing Industry Research Account of the Australian Department of Primary Industry.     

Trace co-attractants in synthetic sex lures for 22 noctuid moths

Summary Trace components contributed significantly to the potency of synthetic sex attractant lures for males of many species of Noctuidae. Improved synthetic blends for 12 moths includingEuxoa ochrogaster andTrichoplusia ni, and new lure blends for 10 moths are described. In every case the trace constituents were structural analogs of the main lure components.     

Observational defects in eighteenth-century British telescopes

Among the several remarkable properties of mercury is that it dissolves many of the metals (but not iron), forming amalgams. It was the recognition of the ready formation of gold and silver amalgams that led to the extraction of precious metals by the amalgamation method. In this article I trace some of the historical aspects associated with the development of the European amalgamation process, first devised by Ignaz von Born in the 1780s. In particular, I describe an international gathering of experts in mining and metallurgy which was held at Skleno in Slovakia in 1786, and the founding there of a society for mining sciences called ‘Die Societät der Bergbaukunde’.     

Trace metals especially Fe+++ as dietary factors for leafhoppers

Summary Some trace metals are required for development and reproduction, and therefore for continuous rearing of the aster leafhopper,Macrosteles fascifrons, on a holidic diet. Requirement for Fe⁺⁺⁺ becomes apparent immediately in the 1st generation; for Cu⁺⁺ and Zn⁺⁺, in the 3rd. The leafhopper has grown normally and continuously for 3 generations in the absence of manganese.We acknowledge the Minnesota Agricultural Experiment Station and the National Institute of Allergy and Infectious Diseases, USA, for financial supports.     

直读光谱法测定钢中的Pb、As、Sn、Nb的研究

钢中Pb、As、Sn、Nd等痕量元素对钢材性能影响很大，近年来开发的钢材系列新产品要求对Pb、As、Sn、Nb等痕量元素进行控制，但采用光谱分析这些元素从未进行研究过。本文选用ARL4460直读光谱仪，通过对仪器检测限和精度的试验、分析条件和样品加工工艺等方面的探索。解决了直读光谱仪仪器分析的系列问题，使ARL4460直读光谱仪高效率应用于钢中Pb、As、Sn、Nb等痕量元素的现场分析。     

Both morphological and molecular characters support speciation of South American siskins by sexual selection

South American siskin radiation was studied by both mitochondrial cytochrome b (mt cyt b) DNA sequencing and homologous phenotypic characters; the latter were coded separately according to sex. Mixed phenetic and molecular (total evidence) dendrograms were constructed and the corresponding analyses suggest that speciation started in the South American siskin group with a north to south separation (Carduelis notata/C. barbata) along the Andean spine. A second split may have taken place around the Peruvian Andean mountains, corresponding to the present distribution pattern of C. olivacea. The most recent speciation events seem to have occurred in three sister species pairs: (i) C. xanthogastra/C. atrata, (ii) C. magellanica/C. yarrellii, (iii) C. cucullata/C. crassirostris. Accumulation of consistent characters in both morphological and molecular data at the basal nodes of the dendrograms indicate that speciation events occurred within a short period of time. Our data also suggest that speciation probably occurred by sexual selection through female mating choice in this radiation. Additionally, studies of variable amino acid residues in the mt cyt b molecule show that the three variable amino acids found are placed in the mitochondrial transmembrane region, which is also part of the hypervariable region in mammals. Each of the three amino acid changes occur in each of the three postulated evolutionary groups. Received 11 September 2001; received after revision 12 October 2001; accepted 15 October 2001     

Satellite DNAs in eukaryotes: a non-adaptive mechanism of speciation which originated with sexual reproduction?

Satellite DNAs may have originated during evolution at the same time as sexual reproduction in order to suppress crossingover between the 2 heterogametic sex chromosomes, and may have acquired a function of sterility barriers in hybrid species during evolution. This origin of satellite DNAs appears to be reflected in different stages of speciation: partial and total heterogametic sex hybrid sterility and full hybrid sterility might correspond to subspecies, semispecies and full species.