(Ni-Sn-M_xO_y)/Pb改性复合电极电解合成L-半胱氨酸的反应

在（Ｎｉ－Ｓｎ）／Ｐｂ合金修饰电极中添加某些金属氧化物进行改性，用于电解合成Ｌ－半胱氨酸反应。结果证明，添加ＷＯ３后电极反应活性大大加强，反应同期转化率有较大提高，选择性也有所提高，添加稀土金属氧化物能有效降低反应阴极过电位，使反应选择性有所提高，但是电极稳定性还有待改善。     

深圳福田白骨壤群落Cr,Ni,Mn的累积及分布

探讨了深圳福田自然保护区白骨壤红树林对Ｃｒ、Ｎｉ、Ｍｎ的吸收、累积及分布．结果表明,该林地土壤Ｃｒ、Ｎｉ、Ｍｎ含量从底层至表层逐步提高;表层（０～３０ｃｍ深）３种元素含量分别为７．９７、２５．０和５３７μｇ·ｇ－１,贮量分别为１０９９．８６、３４５０．００和７４１０６．００ｍｇ·ｍ－２．白骨壤植物各部位Ｃｒ、Ｎｉ、Ｍｎ含量范围分别为０．２８～０．７５、０．４３～７．６５和２５～１５５２μｇ·ｇ－１;植物对表层土壤加权平均富集系数为Ｍｎ＞Ｎｉ≈Ｃｒ．该群落Ｃｒ、Ｎｉ、Ｍｎ的现存累积量分别为６．０６、２０．７６和１６３１．１７ｍｇ·ｍ－２,年净存留累积量分别为０．４３、１．４３和１０７．９８ｍｇ·ｍ－２;林地残留物相应元素储量分别为Ｃｒ７８．００μｇ·ｍ－２、Ｎｉ１５３６．３３μｇ·ｍ－２和Ｍｎ４０５．５４ｍｇ·ｍ－２．该林区３种不同类型群落叶层Ｃｒ、Ｎｉ现存累积量为白骨壤林＞桐花树林＞秋茄林,Ｍｎ为秋茄林＞白骨壤林＞桐花树林．     

长江三峡地区优势植物的化学元素含量特征

分析了三峡地区１６种优势植物２０个元素的自然含量特征。〉１０００μｇ．ｇ＾－１的元素有Ｃａ,Ｋ和Ｍｇ,１００－１０００μｇ．ｇ＾－１的元素有Ａｌ,Ｐ,Ｓｉ,Ｆｅ,Ｓ和Ｍｎ,１０－１００μｇ．ｇ．＾－１的元素有Ｎａ,Ｓｒ,Ｚｎ,Ｂ,〈１０μｇ．ｇ＾－１的元素有Ｔｉ,Ｃｕ,Ｎｉ,Ｃｒ,Ｍｏ,Ｃｄ和Ｖ。     

小葱叶胞质中3种Cu·Zn-SOD的纯化及性质研究

超氧化物歧化酶（ＳＯＤ）是一种消除体内氧自由基损伤的重要因子,可分为ＣｕＺｎ－ＳＯＤ、Ｍｎ－ＳＯＤ和Ｆｅ－ＳＯＤ．作者在小白菜叶中曾发现５种ＳＯＤ,已鉴别其中一种为Ｍｎ－ＳＯＤ,来源于线粒体［１］;其余４种为ＣｕＺｎ－ＳＯＤ,其中２种分别来源于胞质［...     

将Thinopyrum bessarabicum和Thinopyrum elongatum的种质导？…

２个双倍体即Ｃ．Ｓ－Ｔｈｉｎｏｐｙｒｕｍ ｂｅｓｓａｒａｂｉｃｕｍ（ＡＡＢＢＤＤＪＪ ２ｎ＝８ｘ＝５６）和ＧＨＫ－Ｔｈｉｎｏｐｙｒｕｍ ｅｌｏｎｇａｔｕｍ（ＡＡＢＢＤＤＥＥ ２ｎ＝８ｘ＝５６）与普通小麦“中国春”杂交,获得了２个七倍体杂种。对２３个双倍体、中国春、杂种Ｆ１和部分Ｆ２进行麦谷蛋白ＳＤＳ－Ｐａｇｅ电泳,及结合染色体分带技术和田间赤霉病抗性鉴定筛选出由Ｔｈ．ｂｅｓｓａｒａｂｉｃｕｍ和Ｔｈ     

人亲环素B基因的克隆表达及重组蛋白的生物活性

应用ＲＴ－ＰＣＲ方法从人淋巴细胞中扩增出亲环素Ｂ（ｃｙｃｌｏｐｈｉｌｉｎＢ,ＣｙＰＢ）基因,克隆入ｐＥＴ－２８ａ载体中表达．表达产物以包涵体形式存在,占细菌可溶性蛋白的１５％．经Ｎｉ－ＮＴＡ树脂金属螯合亲和层析和ＳｅｐｈａｄｅｘＧ－５０柱层析纯化,ＳＤＳ－ＰＡＧＥ检测呈单一条带,毛细管电泳为单一色谱峰,纯度达９５％．经复性处理,表达产物显示肽基脯氨基顺反异构酶活性     

四种无尾两栖动物的核型和银染

本文报道了二种角蟾和二种树蛙的核型和银染ＮＯＲ：无量出角蟾：２ｎ＝２６（２４＋２ＳＭ），５＋８，ＳＣ和Ａｇ－ＮＯＲｓ位于６ｑ＾ｐｅｒ沙坪角蟾：２ｎ＝２６（１６Ｍ＋８ＳＭ＋２ＳＴ），５＋８，ＳＣ位于１ｑ＾ｐｅｒ，但Ａｇ－ＮＯＲｓ有二对，分别是ｌｑ＾ｐｅｒ和２ｑ＾ｐｅｒ；黑蹼树蛙：２ｎ＝２６（２４Ｍ＋２ＳＭ），５＋８，ＳＣ和Ａｇ－ＮＯＲｓ在ｌｐ＾ｉｎｔｅｒ；背条跳树蛙；２ｎ＝１６（１２Ｍ＋４ＳＭ），Ｓ     

PSⅡ系统放氧复合物中的锰簇模型物

合成了６个模型化合物并用以探讨ＰＳⅡ的放氧复合物（ＯＥＣ）中Ｍｎ簇的结构特征。模型物包含Ｍｎ２（μ－Ｏ）２和μ－Ｏ－μ－羧桥联的二锰结构单元,这些单元中的Ｍｎ－Ｍｎ、Ｍｎ…Ｍｎ和Ｍｎ－Ｏ（Ｎ）结构参数与ＰＳⅡ系统ＯＥＣ的相应数据一致,暗示ＯＥＣ中Ｍｎ簇可能具有类似的结构特点。还有两个模型物包含了卤素阴离子,它们被用于讨论ＰＳⅡ中Ｃｌ＾－１与Ｍｎ的联系。讨论认为,在５个ＰＳⅡ的Ｓ态中,具有高价锰中心     

噬菌 展示法筛选与EphB2结合的短肽

酷氨酸蛋白激酶受体ＥｐｈＢ２的Ｉｇ类似区,克隆到融合表达闰载体ｐＥＴ２８ａ中,阳性克隆经ＩＰＴＧ诱导,表达出氨基端带６个连续组氨酸残基的融合蛋白。利用Ｎｉ－ＮＴＡ金属螯合亲和层析法有变性条件下对表达的蛋白进行纯化,纯度大于９４％。以此纯化蛋白为靶,将其包被于ＥＬＩＳＡ板上,经过三轮亲和筛选,从噬菌体随机７肽库中筛选到１９个具有ＥｐｈＢ２活性的重组噬菌体克隆,对阳性噬菌体克隆的短肽序列进行了分析。     

去锰PSⅡ颗粒放氧活性光活化的部分生化特性研究

羟胺处理使菠菜ＰＳⅡ颗粒丧失绝大部分锰和放氧活性,一定条件下Ｍｎ￣（２＋）能被光氧化重新组装入ＰＳⅡ颗粒并恢复放氧活性。在最适ｐＨ（ｐＨ６．５）下,只有光照和Ｍｎ￣（２＋）为Ｍｎ与Ｓ－态复合物结合所必需,Ｃａ￣（２＋）的存在大大提高了重组锰复合物的水分解活性,Ｃａ￣（２＋）和Ｍｎ￣（２＋）在Ｃａ￣（２＋）结合部位相互竞争。外加入人工电子受体可使光活化效率提高。Ｃｌ￣－在光活化中的作用可部分程度被代替。在光活化和放氧复合物Ｓ－态周转中Ｃｌ的动力学行为不同。光活化为一典型的一级反应。     

Elimination of Heavy Metals from Leachates by Membrane Electrolysis

The elimination of heavy metals from bioleaching process waters (leachates) by electrolysis was studied in the anode and cathode region of a membrane electrolysis cell at current densities of 5–20 mA/cm² using various electrode materials. The leaching waters containing a wide range of dissolved heavy metals, were high in sulfate, and had pH values of approx. 3. In preliminary tests using a rotating disc electrode the current density‐potential curve (CPK) was recorded at a rotation velocity of 0, 1000 and 2000 rpm and a scan rate of 10 mV/s in order to collect information on the influence of transport processes on the electrochemical processes taking place at the electrodes. The electrochemical deposition‐dissolution processes at the cathode are strongly dependent on the hydrodynamics. Detailed examination of the anodic oxidation of dissolved Mn(II) indicated that the manganese dioxide which formed adhered well to the electrode surface but in the cathodic return run it was again reduced. Electrode pairs of high‐grade steel, lead and coal as well as material combinations were used to investigate heavy metal elimination in a membrane electrolysis cell. Using high‐grade steel, lead and carbon electrode pairs, the reduction and deposition of Cu, Zn, Cr, Ni and some Cd in metallic or hydroxide form were observed in an order of 10–40 % in the cathode chamber. The dominant process in the anode chamber was the precipitation of manganese dioxide owing to the oxidation of dissolved Mn(II). Large amounts of heavy metals were co‐precipitated by adsorption onto the insoluble MnO₂. High‐grade steel and to some extent lead anodes were dissolved and hence were proven unsuitable as an anode material. These findings were largely confirmed by experiments using combination electrodes of coal and platinized titanium as an anode material and steel as a cathode material. With both electrode combinations and current densities of 5 or 10 mA/cm², in the cathode region low depositions of 10–20 % Cd, 2–10% Mn, 5–20 % Zn, 1–20 % Co and 5–15 % Ni were measured. By contrast, the elimination of other metals was substantially larger: Fe 40 –60 %, Cu 20–40 %, and Cr 40–60 %. In the anode region the removal of heavy metals was in the order of 30–50%, with Mn being as high as 80 %. The anode materials exhibit good resistance at the current densities tested. The precipitates deposited in both electrode regions contained as main components Al with 10–20 %, Mg with approximately 10 %, and SO₄ with 5–20 %. The solid material in the cathode chamber consisted of relatively high proportions of Zn and Mn. Calcium in the solids indicated the co‐precipitation of calcium sulfate. The main components in the solids of the anode chamber were Mn in the form of pyrolusite, Al as basic sulfate, and Mg. The results indicate that electrochemical metal separation in the membrane electrolysis cell can represent a practical alternative to the metal separation by alkalization. Regarding the main heavy metals Zn, Mn and Ni in the process water, combination electrodes using steel as a cathode material and coal or platinized titanium as an anode material proved to be suitable for eliminating the heavy metals from the aqueous phase. However, for practical application, further work is necessary to improve the efficiency, applicability and costs of the process.     

广州市花都城区绿地土壤肥力与重金属污染分析

在对广州市花都城区绿地土壤取样调查的基础上,采用全国第二次土壤普查养分分级标准和内梅罗污染指数法等对其土壤肥力和重金属污染情况进行分析评价,揭示花都城区绿地土壤存在的问题。结果表明,花都城区绿地土壤容重变幅在1.25～1.75 g·cm–3之间,孔隙度变幅在30.81%～47.42%之间,pH在6.16～7.68之间,有机质含量在四级及以下标准,严重缺乏氮素和磷素。不同绿地类型中,厂区路旁绿地土壤重金属污染最严重,其次为主干道两侧绿地;研究区As污染最严重,Pb次之,未受Zn污染,存在不同程度的Cu、Cd、Cr、Ni、Hg污染。相关性分析表明,土壤pH与全钾、碱解氮含量极显著相关,有机质与全氮极显著相关,全氮、全磷分别与碱解氮、有效磷显著正相关,全钾与碱解氮显著负相关;重金属元素中,Cu与Zn、Cr、Ni极显著相关,Zn与Cu、Pb、Cd、Cr、Ni极显著相关,Pb与Zn、Cd极显著相关,Cr与Cu、Zn、Ni极显著相关,As和Hg与其他重金属元素均无显著相关性。     

底物种类和浓度对污泥重金属生物淋滤效果的影响

以生污泥为材料,研究单质硫(浓度分别为5、10、20 g/L)、FeSO4?7H2O (浓度分别为10、20 g/L）和硫代硫酸钠（浓度分别为10、20 g/L）三种底物的不同浓度对污泥中Zn、Cu、Pb、Cd、Cr和Ni六种重金属生物淋滤效果的影响。结果表明：单质硫的致酸性最好,第4天pH值就达到2.0左右,Zn、Cu、Pb、Cr和Ni的滤出量最大（原污泥Cd未检出）,并以底物投放浓度在10～20 g/L为佳。FeSO4?7H2O的致酸性和重金属滤出量较单质硫弱。硫代硫酸钠在浓度10 g/L时,致酸性和重金属的滤出量介于单质硫和FeSO4?7H2O之间,但浓度20 g/L时滤液呈碱性,重金属难于滤出甚至不滤出。     

Nano nickel oxide modified non-enzymatic glucose sensors with enhanced sensitivity through an electrochemical process strategy at high potential

Development of fast and sensitive sensors for glucose determination is important in food industry, clinic diagnostics, biotechnology and many other areas. In these years, considerable attention has been paid to develop non-enzymatic electrodes to solve the disadvantages of the enzyme-modified electrodes, such as instability, high cost, complicated immobilization procedure and critical operating situation et al. Nano nickel oxide (NiO) modified non-enzymatic glucose sensors with enhanced sensitivity were investigated. Potential scanning nano NiO modified carbon paste electrodes up to high potential in alkaline solution greatly increases the amount of redox couple Ni(OH)(2)/NiOOH derived from NiO, and thus improves their electrochemical properties and electrocatalytical performance toward the oxidation of glucose. The non-enzymatic sensors response quickly to glucose and the response time is less than 5s, demonstrating excellent electrocatalytical activity and assay performance. The calibration plot is linear over the wide concentration range of 1-110 μM with a sensitivity of 43.9 nA/μM and a correlation coefficient of 0.998. The detection limit of the electrode was found to be 0.16 μM at a signal-to-noise ratio of 3. The proposed non-enzymatic sensors can be used for the assay of glucose in real sample.     

Detection of secretion from pancreatic islets using chemically modified electrodes

Secretion of insulin from pancreatic islets was monitored indirectly by detecting zinc. Anodic stripping voltammetric measurements of zinc were done on a bismuth-modified electrode. Comparison of the performance of bismuth-modified electrodes and mercury film electrodes showed that bismuth is an appropriate alternative for Zn detection. The bismuth-coated electrode was used to detect zinc in insulin samples and insulin secreted from pancreatic islets upon stimulation with high concentrations of K(+). Detection of zinc released from pancreatic islets was done in the culture medium without any further cleanup. This detection method can be used to monitor secretion from pancreatic islets in their native environment.     

Multiple parameter cytotoxicity index on dental alloys and pure metals

Palladium (Pd) is a metal frequently used for dental alloys. In order to elucidate controversial options about Pd concerning its biological performances, our study consists in the evaluation of commercial and experimental PFM and C&B precious and semi-precious dental alloys. This investigation was also designated to the establishment of a cytotoxicity index (CI) such as it was described for hemocompatibility testing. The following materials were tested: 36 commercial alloys (Au-, Pd- and Ag-base), 14 experimental alloys (Pd-base established by an experience plan) and pure metals (Ag, Au, Cu, Ni, Cr, In, Sn, Pt, Ti, Zn). The cells culture experiments were carried out with epithelial L132 cells and NIH 3T3 fibroblasts. In vitro cell viability tests show that Pt, Sn, In, Ti, Au and Pd have no cytotoxic effect; Cr, Cu and Ag are toxic, Ni, Zn, and Co are highly toxic. An identical ranking was found with the inflammatory and proliferation tests. Toxic and highly toxic metals induced slight or strong prosthetic dental restoration morphological alterations after 3-days cultures and mostly cell death after 6-days cultures. These effects are dependent on the leakage of the element into the culture medium as revealed by ICP. The addition of Au gives benefit to Pd-Ag alloys, but does not produce any major effect on Pd-Cu alloys. This qualitative ranking can quantitatively be confirmed by cytocompatibility testing after application of a CI.     

Simultaneous detection of the release of glutamate and nitric oxide from adherently growing cells using an array of glutamate and nitric oxide selective electrodes

The simultaneous detection of nitric oxide and glutamate using an array of individually addressable electrodes, in which the individual electrodes in the array were suitably modified with a highly sensitive nitric oxide sensing chemistry or a glutamate oxidase/redox hydrogel-based glutamate biosensor is presented. In a sequence of modification steps one of the electrodes was covered first with a positively charged Ni porphyrin entrapped into a negatively charged electrodeposition paint followed by the manual modification of the second working electrode by a bienzyme sensor architecture based on crosslinked redox hydrogels with entrapped peroxidase and glutamate oxidase. Adherently growing C6-glioma cells were grown on membrane inserts and placed in close distance to the modified sensor surfaces. The current responses recorded at each electrode after stimulation of glutamate and NO release by means of K+ and bradykinin clearly demonstrate the ability of the individual electrode in the array to detect the analyte towards which its sensitivity and selectivity was targeted without interference from the neighbouring electrode or other analytes present in the test mixture.     

Competition alters plant species response to nickel and zinc

Phytoextraction can be a cost-efficient method for the remediation of contaminated soils. Using species mixtures instead of monocultures might improve this procedure. In a species mixture, an effect of heavy metals on the species' performance can be modified by the presence of a co-occuring species. We hypothesised that (a) a co-occuring species can change the effect of heavy metals on a target species, and (b) heavy metal application may modifiy the competitive behaviour between the plants. We investigated these mechanisms in a greenhouse experiment using three species to serve as a model system (Carex flava, Centaurea angustifolia and Salix caprea). The species were established in pots of monocultures and mixtures, which were exposed to increasing concentrations of Ni and Zn, ranging from 0 to 2,500 mg/kg. Increased heavy metal application reduced the species' relative growth rate (RGR); the RGR reduction being generally correlated with Ni and Zn concentrations in plant tissue. S. caprea was an exception in that it showed considerable Zn uptake but only moderate growth reduction. In two out of six cases, competitors significantly modified the influence of heavy metals on a target species. The interaction can be explained by an increased uptake of Zn by one species (in this case S. caprea) that reduced the negative heavy metal effect on a target species (C. flava). In two further cases, increasing heavy metal application also altered competitive effects between the species. The mechanisms demonstrated in this experiment could be of relevance for the phytoextraction of heavy metals. The total uptake of metals might be maximised in specific mixtures, making phytoextraction more efficient.     

Amperometric sensors based on Ni/Al and Co/Al layered double hydroxides modified electrode and their application for hydrogen peroxide detection

Two different hydrogen peroxide sensors were constructed with Ni/Al and Co/Al layered double hydroxides (LDHs) modified glassy carbon electrodes (GCE). Ni (Co)/Al-LDHs were synthesized by electrochemical method and were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The advantages and shortcoming of the two hydrogen peroxide sensors were described in detail. Compared to Co/Al-LDHs modified electrode, sensors fabricated by Ni/Al-LDHs showed quicker heterogeneous electron transfer rate constants (k(s)), lower detection and better reproducibility. But Co/Al-LDHs modified electrode held the advantages of wider linear range and higher sensitivity. Further more, the different catalytic redox mechanisms of hydrogen peroxide on the Ni/Al/GCE and Co/Al/GCE were firstly comparatively explored.