Tuning the energy level and photophysical and electroluminescent properties of heavy metal complexes by controlling the ligation of the metal with the carbon of the carbazole unit

Four novel Ir-III and Pt-II complexes with cyclometalated ligands bearing a carbazole framework are prepared and characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. Single-crystal X-ray diffraction studies of complexes 1, 3, and 4 reveal that the 3- or 2-position C atom of the carbazole unit coordinates to the metal center. The difference in the ligation position results in significant shifts in the emission spectra with the changes in wavelength being 84 nm for the Ir complexes and 63 nm for the Pt complexes. The electrochemical behavior and photophysical properties of the complexes are investigated, and correlate well with the results of density functional theory (DFT) calculations. Electroluminescent devices with a configuration of ITO/NPB/CBP:dopant/BCP/AlQ(3)/LiF/Al can attain very high efficiencies.

Determination of heavy metal ions by capillary electrophoresis with contactless conductivity detection after field-amplified sample injection

A method has been developed for determining of heavy metal ions by field-amplified sample injection capillary electrophoresis with contactless conductivity detection. The effects of the 2-N-morpholinoethanesulfonic acid/histidine (MES/His) concentration in the sample matrix, the injection time and organic additives on the enrichment factor were studied. The results showed that MES/His with a low concentration in the sample matrix, an increase of the injection time and the addition of acetonitrile improved the enrichment factor. Four heavy metal ions (Zn2+, Co2+, Cu2+ and Ni2+) were dissolved in deionized water, separated in a 10 mM MES/His running buffer at pH 4.9 and detected by contactless conductivity detection. The detection sensitivity was enhanced by about three orders of magnitude with respect to the non-stacking injection mode. The limits of detection were in the range from 5 nM (Zn2+) to 30 nM (Cu2+). The method has been used to determine heavy metal ions in tap water.

药用牡丹资源与重金属污染问题的研究

我国牡丹资源丰富、药用历史悠久、药材出口量大。近年来国际上对进口植物药的重金属限量标准不断提高，已成为影响丹皮出口的最大贸易壁垒之一，严重阻碍了丹皮产业化进程。为了提高我国丹皮药材整体质量水平和国际竞争力，本试验探讨了不同产地、不同种质资源的丹皮与Cu、Cd、Pb、As四种重金属的关系，重点研究了两个代表性品种对重金属Cu的富集规律，分析了重金属Cu对牡丹生长、生理和药材品质的影响。实验中采用火焰原子吸收分光光度法（FAAS ）和电感耦合等离子体质谱法（ICP-MS）为基本检测手段来分析样品中重金属元素的含量，从植物与重金属相互关系的角度对牡丹药用、花药兼用以及生态修复可行性等方面进行了系统研究。结果如下： 1. 丹皮重金属含量与牡丹种质资源和栽培环境关系密切。野生种中滇牡丹丹皮中Cu、Cd含量相对较高，多数野生种丹皮中Pb、As含量较栽培种偏高；铜陵产区的丹皮重金属含量明显高于其它产区，铜尾矿上栽培出产的丹皮重金属Cu含量明显超标，建议其改变种植模式，可以考虑丰富牡丹品种，开发生态旅游、观赏栽培。 2. 综合比较同一地块的7个常用药用品种发现，‘JPH’和‘CKL’品种对重金属富集能力相对较弱。‘JPH’是传统的优良观赏品种，适宜花药兼用；结合前期研究的结果‘CKL’药效成分含量相对较高，药用价值较高，适宜药用栽培。 3. 对药用牡丹品种‘凤丹’和‘建始粉’外施不同浓度CuSO4溶液处理后发现，丹皮中重金属富集量与外施重金属浓度成显著正相关。当外施Cu 浓度超过150mg/kg 时，两个品种的丹皮中Cu含量均已超标。 4. 重金属Cu对牡丹生长的影响效应与重金属浓度和植物体自身部位有关。当外施Cu浓度小于600mg/kg 时，对牡丹生长有一定的促进作用，主要表现在地上部分；超过600mg/kg 时，对牡丹生长有抑制作用，随着浓度增大，毒害症状愈加明显。地下部主要表现出受抑制作用，抑制效应随外施浓度增大而加重。 5. 牡丹通过自身的生理生化调节机制抵抗Cu胁迫对细胞造成的氧化伤害：低浓度Cu可以刺激抗氧化酶系统SOD和POD 活性升高，高浓度下SOD和 POD活性则显著降低。相同处理条件下‘凤丹’品种的抗铜性要高于‘建始粉’。 6. 本试验未发现外施Cu处理对丹皮中药效成分丹皮酚、芍药苷产生影响。 7. ‘凤丹’及‘建始粉’根系铜富集质量分数均达到超富集植物的要求，因此牡丹可能在重金属Cu污染的环境修复方面存在巨大潜力。

镉、铅排异大白菜品种的筛选和鉴定及安全生产调控技术

随着工农业的快速发展，土壤重金属尤其Cd和Pb污染日益严重。筛选和培育具有重金属低积累特性的农作物排异品种被认为是当前应对土壤重金属污染最为合理和有效的途径之一。本文通过盆栽试验、大田试验和砂培试验，研究了大白菜品种对Cd和Pb的吸收和积累的品种差异、对Cd、Pb胁迫的响应以及大白菜安全生产的调控技术，得出以下结论： 1) 盆栽梯度试验中，80种大白菜地上部对Cd的吸收存在显著差异(p < 0.05)。在3种Cd处理下(1.0, 2.5和5.0 mg/kg)，80种大白菜Cd含量浓度范围分别为(mg/kg) 0.22–2.46, 0.90–14.10和2.03–18.01, 其平均值分别为 0.79, 3.76 和6.79 mg/kg DW。大白菜对Cd胁迫具有较强的耐性。大田试验中，15种大白菜的富集系数和转运系数与盆栽梯度试验的结果基本一致。排异植物的筛选和鉴定标准包括：(1)该植物的地上部和根部的Cd含量都很低或者可食部位低于有关标准；(2) 富集系数(BF) < 1.0；(3) 转运系数(TF) < 1.0；(4)该植物具有较高的Cd耐性，在较高的Cd污染下能够正常生长且生物量无显著下降。采用此标准，结合盆栽梯度试验和大田试验结果，北京新3号、绿星70和丰源新3号可鉴定为Cd排异品种。秋傲和赛新5号具有排异Cd特性，但其对Cd的耐性较差。 2) 盆栽梯度试验中，在Pb投加浓度为500和1500 mg/kg处理下，30种大白菜地上部对Pb的吸收存在显著差异 (p < 0.05)，其Pb浓度的范围分别为：0.52–8.68 和1.86–16.20 mg/kg, 其平均值分别为3.01 和6.87 mg/kg DW。并且，随着Pb浓度的增加，白菜地上部Pb含量有随之增加的趋势。大白菜对Pb具有较强的耐性。低浓度的Pb处理对大白菜的生物具有一定的促进作用。结合盆栽试验和大田试验的结果，秋傲、世博秋抗和福星80可鉴定为Pb排异大白菜品种。 3) 砂培试验中，在Cd和Pb胁迫下，大白菜地上部的丙二醛(MDA)含量增加，随着Cd处理浓度的增加，超氧化物歧化酶(SOD)活性呈现先下降后上升接着下降的趋势，酸菜王的SOD活性要高于北京新3号SOD的活性。随着Pb处理浓度的增加，福星80地上部的SOD活性随之增加，而绿星大棵菜地上部的SOD活性先下降后增加。在不同梯度的Cd处理下，大白菜地上部的可溶性蛋白(SP)含量未见显著降低，甚至有所增加，而在不同梯度的Pb处理下，大白菜地上部的SP含量有所降低。 4) 施用改良剂可升高土壤的pH值和降低土壤中的有效态Cd，从而对大白菜的生长具有促进作用。施用改良剂可显著降低大白菜对Cd和Pb的吸收和累积。

黄土高原不同土壤中Cd形态分级及其生物有效性研究

研究黄土高原主要农田土壤重金属Cd的形态与生物有效性的关系,为评价本区土壤重金属Cd污染程度及其生物有效性提供一定的理论与数据依据。【方法】以黄土高原自北向南采集的12个0~20 cm耕层土壤为供试土样,通过室内分析和盆栽试验,研究了黄土高原石灰性土壤中不同形态Cd的分布特征及其生物有效性。【结果】黄土高原农田土壤Cd各形态总体分布特征为:有机结合态Cd、铁锰氧化物结合态Cd>碳酸盐结合态Cd>交换态Cd>残渣态Cd,自北向南各形态Cd含量均呈不同程度的增加趋势。各土壤类型间铁锰氧化物结合态Cd及碳酸盐结合态Cd平均含量均表现为:干润砂质新成土<黄土正常新成土<简育干润均腐土<土垫旱耕人为土,自北向南依次增加。碳酸盐结合态Cd和全Cd含量主要受到全氮、有效磷和砂粒含量的影响,且全氮和有效磷含量对其的影响为正效应。铁锰氧化物结合态Cd含量主要受全氮、有效磷、砂粒和粉砂粒含量的影响,且全氮、有效磷和粉砂粒含量对其的影响为正效应。土壤中各形态Cd含量与有机质、C/N、pH、CaCO3、粘粒含量的相关性均不显著,其中与C/N、pH、粘粒含量呈负相关。Cd在小麦茎叶层的含量小于根系;而作物不同部位Cd累积量表现...

Effects of temperature, hypoxia, ammonia and nitrate on the bleaching among three coral species

Coral bleaching, which is defined as the loss of colour in corals due to the loss of their symbiotic algae (commonly called zooxanthellae) or pigments or both, is occurring globally at increasing rates, and its harm becomes more and more serious during these two decades. The significance of these bleaching events to the health of coral reef ecosystems is extreme, as bleached corals exhibited high mortality, reduced fecundity and productivity and increased susceptibility to diseases. This decreased coral fitness is easily to lead to reef degradation and ultimately to the breakdown of the coral reef ecosystems. Recently, the reasons leading to coral bleaching are thought to be as follows: too high or too low temperature, excess ultraviolet exposure, heavy metal pollution, cyanide poison and seasonal cycle. To date there has been little knowledge of whether mariculture can result in coral bleaching and which substance has the worst effect on corals. And no research was conducted on the effect of hypoxia on corals. To address these questions, effects of temperature, hypoxia, ammonia and nitrate on bleaching of three coral species were studied through examination of morphology and the measurement of the number of symbiotic algae of three coral species Acropora nobilis, Palythoa sp. and Alveopora verrilliana. Results showed that increase in temperature and decrease in dissolved oxygen could lead to increasing number of symbiotic algae and more serious bleaching. In addition, the concentration of 0.001 mmol/L ammonia or nitrate could increase significantly the expulsion of the symbiotic algae of the three coral species. Except for Acropora nobilis, the numbers of symbiotic algae of other two corals did not significantly increase with the increasing concentration of ammonia and nitrate. Furthermore, different hosts have different stress susceptibilities on coral bleaching.

Environmental changes reflected by sedimentary geochemistry in recent hundred years of Jiaozhou Bay, North China

Sediment geochemical technique was employed to assess how the sediment records reflect the environmental changes of Jiaozhou Bay, a semi-enclosed bay adjacent to Qingdao, China. In the past hundred years, Jiaozhou Bay has been greatly impacted by human interventions. A dated core sediment by Pb-210 chronology was analyzed for trace metals including Li, Cd, Cr, Pb, Cu, Ni, Co, Zn together with C, N, P and BSi. Based on the research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages: (1) before the 1980s characterized by relatively low sedimentation rate, weak heavy metal pollution and scarce eutrophication; (2) from the 1980s to 2000, accelerating in the 1990s, during which high sedimentation rates, polluted by heavy metals and the frequent occurrence of red tide; (3) after 2000, the period of the improvement of environment, the whole system has been meliorated including the heavy metal pollution and hypernutrification. (c) 2006 Elsevier Ltd. All rights reserved.