A novel electrochemical method for simultaneously measuring diffusion coefficient and ion transference number

This paper introduces a new method to estimate the diffusion coefficient and transference number of a salt or an electroactive ion in a solution with little or no supporting electrolyte. The above two parameters can be obtained from a single potential step experiment without previous knowledge of either one. It would appear that the method could also be used in the study of ion transport in a high viscosity solvent or a solid electrolyte. (C) 1998 Elsevier Science S.A.

Recurrence plot analysis of DNA sequences

Recurrence plot technique of DNA sequences is established on metric representation and employed to analyze correlation structure of nucleotide strings. It is found that, in the transference of nucleotide strings, a human DNA fragment has a major correlation distance, but a yeast chromosome's correlation distance has a constant increasing. (C) 2004 Elsevier B.V All rights reserved.

重金属胁迫相关基因PvSR2在大肠杆菌中表达和转化烟草

近年来植物重金属的耐性机制研究及抗重金属基因工程取得了很大进展。本文将来自于菜豆(Phaseolus vulgaris)的特异性重金属胁迫相关基因PvSR2 (Phaseolus vulgaris stress-related protein, PvSR)的cDNA序列克隆到大肠杆菌高效表达载体pBV221的PR PL启动子的下游，构建了原核表达载体pBV221-PvSR2。通过温度诱导，在大肠杆菌中成功地高效表达了PvSR2基因。经重金属(CdCl2)抗性检测，实验组比对照组有明显的抗性。 同时，将该基因克隆到植物转达化中间载体pCAMBEIA2301的花椰菜花椰病毒的35S启动子下游，利用根癌农杆菌(Agrobacterium tumefaciens)Ti质粒介导的遗传转化系统，成功地将该基因导入了烟草的基因组，获得了转基因植株。

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) from a large shallow, eutrophic lake of the subtropical China

Tissue distributions and seasonal dynamics of the hepatotoxic microcystins-LR and -RR in a freshwater snail (Bellamya aeruginosa) were studied monthly in a large shallow, eutrophic lake of the subtropical China during June-November, 2003. Microcystins (MCs) were quantitatively determined by High-Performance Liquid Chromatography (HPLC) with a qualitative analysis by a Finnigan LC-MS system. On the average of the study period, hepatopancreas was the highest in MC contents (mean 4.14 and range 1.06-7.42 mug g(-1) DW), followed by digestive tracts (mean 1.69 and range 0.8-4.54 mug g(-1) DW) and gonad (mean 0.715 and range 0-2.62 mug g(-1) DW), whereas foot was the least (mean 0.01 and range 0-0.06 mug g(-1) DW). There was a positive correlation in MC contents between digestive tracts and hepatopancreas. A constantly higher MC content in hepatopancreas than in digestive tracts indicates a substantial bioaccumulation of MCs in the hepatopancreas of the snail. The average ratio of MC-LR/MC-RR showed a steady increase from digestive tracts (0.44) to hepatopancreas (0.63) and to gonad (0.96), suggesting that MC-LR was more resistant to degradation in the snail. Since most MCs were present in the hepatopancreas, digestive tracts and gonad with only a very small amount in the edible foot, the risk to human health may not be significant if these toxic parts are removed prior to snail consumption. However, the possible transference of toxins along food chains should not be a negligible concern. (C) 2004 Elsevier Ltd. All rights reserved.

黄土坡面土壤侵蚀中溶质随径流迁移的水动力特性研究

通过对比分析坡面水流的水动力参数与径流溶质迁移量间的关系,研究了不同地表状况下黄土坡面土壤溶质随径流迁移的水动力学特性,以求深入了解和认识坡面土壤侵蚀中溶质随径流迁移的本质机理。研究结果表明:不同坡面地表状况下,糙率系数和平均水深之比(n/h)与侵蚀过程中随径流迁移的溶质存在一定的关系,径流溶质Br-平均浓度、径流溶质Br-的平均流失率以及径流溶质Br-的相对流失量均随n/h的增加而减小。径流溶质Br-的平均流失率以及径流溶质Br-的相对流失量与水流水动力学参数n/h具有指数关系。

The mechanism of energy loss and transition in a flow with submerged vegetation

The mechanism of energy balance in an open-channel flow with submerged vegetation was investigated. The energy borrowed from the local flow, energy spending caused by vegetation drag and flow resistance, and energy transition along the water depth were calculated on the basis of the computational results of velocity and Reynolds stress. Further analysis showed that the energy spending in a cross-section was a maximum around the top of the vegetation, and its value decreased progressively until reaching zero at the flume bed or water surface. The energy borrowed from the local flow in the vegetated region could not provide for spending; therefore, surplus borrowed energy in the non-vegetated region was transmitted to the vegetated region. In addition, the total energy transition in the cross-section was zero; therefore, the total energy borrowed from the flow balanced the energy loss in the whole cross-section. At the same time, we found that there were three effects of vegetation on the flow: turbulence restriction due to vegetation, turbulence source due to vegetation and energy transference due to vegetation, where the second effect was the strongest one. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

具有环氧化酶-2选择性抑制活性的多取代蒽醌的合成

1-甲基-2-甲氧羰基-3, 6, 8-三羟基-7-甲氧基蒽醌是从唐菖蒲干球茎中分离到的具有环氧化酶-2选择性抑制活性的多取代蒽醌类化合物。本文试图合成该化合物，实现了其类似物的合成，同时发现了几个未见报道的反应。 1．通过Diels-Alder 反应合成了关键中间体——3-甲基-5-羟基-1, 2, 4-苯三甲酸三甲酯，1-COOMe选择性水解产物与1, 2, 3-三甲氧基苯进行分子间Friedel-Crafts反应的产物再进行分子内Friedel-Crafts反应得到了目标产物的类似物1-甲基-2-甲氧羰基-3-羟基-6，7，8-三甲氧基蒽醌（路线1）。目标产物及其它类似物的合成正在进行中。 2．以乙酰乙酸甲酯和巴豆醛为原料，经过Michael加成、分子内的Aldol反应、芳香化、选择性甲酰化和还原反应，得到关键中间体2-甲基-3-羟甲基-6-甲氧基苯甲酸甲酯及其衍生物。通过该化合物与3，4，5-三甲氧基苯甲酸甲酯进行Friedel-Crafts烷基化反应得到了多取代的二苯基甲烷衍生物，拟进一步关环合成目标化合物（路线2）。 3．发现邻甲氧基苯甲酸甲酯中酯甲基可以被正丁基锂和仲丁基锂中烷基交换生成相应的酯，反应的机理不明确。当使用叔丁基锂时，得到的是邻甲氧基苯基叔丁酮，这个方法可以用来合成芳基叔丁酮类化合物。 4．以2-苄氧基-6-甲基苯甲酸甲酯为原料进行氯甲基化反应时，以苯和二氯乙烷作溶剂，发生了苄基的迁移和芳环的偶联，分别得到2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基联苯和2，2'-二甲基-3，3'-二甲氧羰基-4，4'-二羟基-5，5'-二苄基联苯。这是对称联苯合成的新方法。 5．水杨酸羟基邻对位的选择性甲酰化可以分别通过水杨酸和水杨酸甲酯用HMTA/CF3COOH来实现。 6．Lewis酸催化3，4，5-三甲氧基苄醇环化成1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10,15-dihydro-5H-trbibenzo [a, d, g] cyclononene (NDTC)，产率(54%)高于已有方法（12%）。 Methyl 3,6,8-trihydroxy-7-methoxy-1-methylanthraquinone-2-carboxylate is a new COX-2 selective inhibitor isolated from Gladiolus gandavensis. Two strategies were investigated to synthesis this compound, in which some important reactions were discovered. 1. The key intermediate 5-hydroxy-3-methylbenzene-1,2,4-tricarboxylic acid 2,4-dimethyl ester was prepared via Diels-Alder reaction followed by selective hydrolysis of 1-COOMe. This compound was coupled with 1,2,3-trimethoxybenzene and the product undergo intramolecular Friedel-Crafts reaction to give methyl 3-hydroxy-5,6,7-trimethoxy-1-methylanthraquinone-2-carboxylate (1st route). The target compound and other analogues are being prepared with the same procedure. 2. The key intermediates methyl 3-hydroxymethyl-6-methoxy-2-methylbenzoate and its derivatives were prepared starting from crotonaldehyde and methyl acetoacetate via Michael addition, intramolecular aldol reaction, aromatization, formylation and reduction. The intermediates were coupled respectively with derivatives of gallic acid to give polysubstituted diphenylmethane. However, attempts to cyclize these compounds to the target compounds and analogues were not successful (2nd route). 3. In the process for ortho-lithiation of methyl 2-methoxybenzoate, the substrate converted respectively to n-butyl 2-methoxybenzoate and sec-butyl 2-methoxybenzoate when n-BuLi and sec-BuLi were used. However, tert-BuLi reacted with methyl 2-methoxybenzoate afford 2-methoxyphenyl tert-butyl ketone, which could be used to synthesize aryl tert-butyl ketones. 4. The transformtion of methyl 2-benzoxy-6-methylbenzoate to dimethyl 4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in benzene, and dimethyl 5,5'-dibenzyl-4,4'-dihydroxy-2,2'-dimethylbiphenyl-3,3'-dicarboxylate in 1,2-dichloroethane in the presence of ZnCl2 provides a new method for the synthesis of symmetric biphenyl. 5. The formylation of salicylic acid at C-5 and methyl 2-hydroxybenzoate at C-3 could be regioselectively realized by using HMTA/CF3COOH. 6. Racemic 1, 2, 3, 6, 7, 8, 11, 12, 13-nonamethoxyl-10, 15-dihydro-5H-trbibenzo [a, d, g] cyclononene was prepared via Lewis acids catalyzed trimerization of 3, 4, 5-trimethoxylbenzyl alcohol with yield (54%) higher than the reported procesure (12%).

Enhanced electrochemical properties of nanocomposite polymer electrolyte based on copolymer with exfoliated clays

In this present work, a polymer electrolyte based on polymer/clay nanocomposite has been developed. Montmorillonite (MMT) clay was used as the filler. due to its special size in length and thickness, and its sandwich type structure. The obtained gel polymer electrolytes have high ionic conductivity up to 2.5 mS cm(-1) with high cationic transference number (about 0.64) at room temperature. The influences of the filler on the membrane morphology. the solvent uptake, the ionic conductivity, and the cation transport number were investigated, and thus the significant contribution from the exfoliated organophilic MMT was identified.

Size-dependent phase transfer of gold nanoparticles from water into toluene by tetraoctylammonium cations: A wholly electrostatic interaction

In this study, it is demonstrated that the tetraoctylammonium cation can be used directly as a phase-transfer reagent of negatively charged water-based gold nanoparticles. The transference is size-dependent and is based on a wholly electrostatic interaction.

Vibronic transitions and site substitution of Eu2+ and codoped ions in KMgF3 : Eu-X (X=Ce, Cr, Gd, Cu) system

The high-resolution emission spectra of KMgF3 : Eu and KMgF3 : Eu-X(X = Ce, Cr, Gd, Cu) single crystals were measured at 300 and 77 K. The vibronic side bands of Eu2+ were characterized and an assignment of the normal mode frequencies to particular vibrations has been made. The correlation between the vibronic frequencies of Eu2+ and the site substitution of other co-dopcd ions was first found. The relationship between vibronic intensity of Eu2+ and other doped ions concentration showed that Cr3+, Gd3+ ions competed K+ sites with Eu2+ ions. Ce3+ and Eu3+ occurred the electron transference. The introduction of Cu+ made for Eu2+ substuting for K+ sites.

Persistent organic pollutant residues in the sediments and mollusks from the Bohai Sea coastal areas, North China: An overview

The Bohai Sea costal area is one of the most developed zones of China and the sewage water from populous and developed cities, including Beijing, Tianjin. Qinhuangdao and Dalian is discharged into the Bohai Sea. Additionally, its semi-enclosed characteristic restricts water exchange, which leads to high accumulation of pollutants in the environment. This overview presents the residues of 6 classes of Persistent Organic Pollutants (POPs). including PAHs, DDTs. HCHs, PCBs and PCDD/Fs. in the sediments and mollusks of the Bohai Sea through analyzing previous literatures. In the sediments. the highest PAH concentrations were detected in the vicinities of Qinhuangdao, while the northeast corner of the Bohai Bay possessed the highest levels of DDTs and PCBs. The investigations on HCHs and PCDD/Fs distributions on the whole sea scale have not been reported. In mollusks, PAH concentrations were in the same order of magnitude in the whole Bohai Sea, so were DDTs. HCHs and PCBs, while the outlier maximum values of PCDDs and PCDFs occurred in Yingkou. In general, the POPs residues in mollusks collected from Shandong Province were higher than the other areas. The compositions of DDTs, HCHs and PCBs in sediments indicated their recent usage. By comparing POP concentrations in sediments with the recommended criterions, it was shown that some individual PAH compounds occasionally associated with adverse biological effects in the vicinities of the Liaodong Bay and Qinhuangdao, and the Liaohe River Estuary were heavily contaminated with DDTs, but PCBs were all below the thresholds. In order to reveal the transference and transformation of POPs in the environment, further studies concerning with their behavior, fate and bioaccumulation in the different trophic levels should be programmed. Moreover, laws and regulations should be enforced to ban the illegal usage of POPs-containing pesticides to guarantee health of the environment and human. (C) 2008 Elsevier Ltd. All rights reserved.

表生条件下铊矿物的氧化溶解动力学及其反应性迁移实验研究

贵州省兴仁县滥木厂铭矿床是世界上唯一的铭的独立矿床。多年来，由于对蛇矿产资源的开发，大量未及时提取和利用的含佗矿石堆积于地表，经过风化淋滤作用，进入当地的水源和土壤，并通过食物链进入人体。20世纪60-70年代，滥木厂地区有近1000名村民患有不同程度的铂中毒，轻者脱发、视力减退，重者失明、丧失劳动力，至今在该地区仍可见到铭中毒患者。该区成为世界上唯一爆发过大规模馆中毒的病发区。馆又是人体的非必需元素，体内任何含量的馆都会对人体造成危害。饮用水的安全标准中，铭的含量不得超过1μg／L。因此对表生条件下，含铂矿物的氧化溶解动力学以及反应性迁移的实验研究具有重要的现实意义。通过对滥木厂铭矿床中的主要含铭矿物（红铭矿）在酸性矿水条件下的氧化溶解过程、光照旧光照射和汞弧灯照射）对铭价态改变的影响，以及酸性矿水条件下铁对蛇吸附的实验研究，得到如下几点认识：1．红铭矿的氧化溶解动力学实验表明：红铂矿的氧化溶解速率受到温度、氧化剂中阴离子种类及氧化剂浓度的影响。随着温度的升高，红蛇矿的氧化速率增高；Cl-离子的存在更有助于红锭矿的氧化溶解，表现为氧化溶解速率的增高；随着氧化剂浓度的升高，红铭矿的氧化速率逐渐降低，这主要是由于高铁浓度下，红佗矿表面形成了一层厚约2nm的铁硫化合物的膜，减缓了红铭矿进一步溶解。红铭矿表面形态和成分的电镜分析表明，红铭矿表面具有较多的活性点，因此含铭矿石在初露地表时对环境的污染比较强烈，经过风化淋滤作用后，红铭矿表面的活性点减少，加之硫铁化合物膜的形成，阻止了其对环境的进一步污染。但这并不排除一旦环境介质改变，红铭矿表面氧化形成的膜被破坏，红铭矿的新鲜表面暴露出来，活性点增多，溶解性加强，继续对周围环境造成强烈的污染。从红蛇矿24小时溶解的总馆量来看，酸性矿水条件下红佗矿的氧化溶解是贵州省兴仁县滥木厂地区佗污染的一个重要来源。2．铭的光致氧化实验结果表明：无论日光还是汞弧灯照射，水溶液中的T1（I）均可被氧化成T1（III）。州值越低、光照强度越大，铭的光氧化速率越快，UVB区的紫外光对铭的光氧化起着主要作用，微生物作用在本实验条件下，相对于光氧化作用并不明显。3．铁对铭的吸附实验表明：铁的水合氧化物对水溶液中铭的吸附除受溶液的pH值和吸附剂的阴离子种类的影响外，主要与佗的价态有直接关系。铁的水合氧化物对Tl（I）具有一定的吸附能力，阴离子种类对T1（I）吸附的作用稍有差别，C1-离子存在时，铁对Tl（I）的吸附更强一些吸附率达到50％左右，而S叮一离子存在条件下，铁对Tl（I）的吸附率小于20％。碱性（pH＝10左右）条件下，铁对T1（I）的吸附较中胜条件更明显一些。T1（III）由于自身的水解作用很强，在不同pH值和不同阴离子存在条件下，与Fe（III）均可发生共沉淀作用而被完全从水溶液中脱除。利用光照将Tl（I）氧化成Tl（III），再利用T1（III）易被沉淀或共沉淀吸附的特性，将Tl以Tl（OH）3，的形式吸附固定下来，降低了铭的活动性，进而可以减少铭对环境的影响，为锭污染的环境治理提供了重要的理论依据。

职业倦怠与自我和谐、人际信任的关系研究：中学校长与一般教师的对比

Job Burnout has been a focus of the Occupational Stress Research. As a typical,helping occupation, teacher has attracted widely attention and researches in the areas of pedagogy and psychology. The special subgroup of teacher, headmasters who are the elites of the Basic Education, is ignored. The research about principals’ Job Burnout is nearly blank after analyzing related documents and information. With the development of the society, people pay more and more attention to the education and put more demands on the headmasters, especially middle-school principals. They are required not only to be good educators, who are equipped with all the inner qualities as a teacher, but also good managers. So the main purpose of this research was to compare the principal group with ordinary teacher group, and reveal underling factors, such as background variables and psychological protection variables. A representative sample of Wenzhou middle school principals sized 192 and a sample of middle school teacher sized 302 were sampled from various schools. The educational version of burnout inventory, self consistency scale, and interpersonal trust scale were administrated to the two samples, together with some demographic variables of interest. The applicability and equivalence of the three instruments used in this study were checked. Based on well-established reliability and cross-sample congruence of measures, the difference between principals and teachers was test. Then the contributing factors were analysis gradually. The five background variables were examined one by one in the two samples separately. A multiple covariance analysis was conducted to test whether there remained any difference between these two samples on the variables of interest. Regression analysis was used to further control the effect of self harmony and interpersonal trust to test the difference between two samples. Mediating analysis was conducted to build the relationship among the three constructs. The main results of the research were stated as following: 1. The internal consistency coefficients of all the scales were good, and no difference exited between the two groups. The measurement equivalence of three instruments was established well. The measures could be applied to and comparing the two samples. 2. The self-harmony, and interpersonal trust of principals were better than the ordinary middle-school teachers. Job Burnout of principals was significant lower than teachers. 3. Demographic variables like the gender, age groups, income levels, disricts, and the type of school, were important influencing factors. The difference patterns of the variables on these five variables in two samples had similarity and distinction. 4. After controlling the background variables, there remained significant difference between principals and teachers on the variables of interest. 5. Job Burnout negatively correlated with self-harmony and interpersonal trust. That is to say，the lower the degree of self-harmony and interpersonal are, the serious of the Job Burnout is, The correlation between the self-harmony and the interpersonal trust was positive. 6. After statistically controlling the background variables and psychological variables, there still exited significant difference between two groups of this study. Also, self harmony and interpersonal trust were significant protection predictors to different aspect of job burnout. 7. Mediating analysis was conducted to the residual score of the three constructs after controlling the five variables and group membership. Self harmony partially mediated the relationship between interpersonal trust and job burnout. That is, interpersonal trust had indirect effect to burnout mediated by self harmony, also had direct effect to burnout.

本科实习男护生压力源、应对方式与心理健康关系的研究

Objectives:To investigate stressor and stress level,coping styles and mental health of male nursing undergraduates in clinical practice;To find out the factors that influence mental health of male nursing undergraduates in clinical practice and to put forward some suggestions to improve the mental health status of male nursing undergraduates. Methods: After doing many literaturere search both at home and abroad,I gather further consulting many nursing undergraduates in clinical practice,Finally I formulate the “Nursing Student's Clinical Stressor Scale”.80 male nursing ungraduates from Bengbu Medical Colledge were recruited. While 140 female nursing ungraduates who were in clinical practice in the same period of time were taken as a comparative group.The following questionnaire package including a background questionnair,Nursing Student's Clinical Stressor Scale NSCSS,Simplified Coping Style Questionnaire SCSQ,The Symptom Checklist 90 SCL-90 were distributed and collected together in the 14th week during the clinical practice.Of the 220 questionnaires were distributed and 198 were found to valid,the valid callback rate was 92%.The endudeed 77 were male and 121 were female .Statistices analysis was performed by SPSS13.0 and AMOS5.0 software. Results： 1.25% of male nursing undergraduates had a higher level of stress, mainly from employment,major,working nature,working contents and so on.Compared with female nursing undergraduates,male nursing undergraduates underwent a higher pressure in the employment and the profession aspect,but lower in their insufficient knowledge and ability.There was a significant negative correlation between the male undergraduates’ stress level and their satisfaction degree to clinical nursing teaching and the professional title of the clinical teachers,but it was positively correlated with their family monthly income. Stress level of female nursing undergraduates positively related with the number of children in their families,but negatively correlated with their family monthly income; 2.Male nursing undergraduates' coping style both positive and negative coping styles were adopted by male nursing undergraduates but mean at while positive coping styles.The positive coping styles adopted by male nursing undergraduates were significantly lower than that adopted by female nursing undergraduates; 3.The scores of depression,interpersonal sensitivity and anxiety in male nursing undergraduates were significantly higher than those of the nationwide youths norm.Alist all subscales scores of male nursing group were more than those of female nursing undergraduates except for fear subscale. Mental health of male nursing undergraduates was inversly correlated with the professional title of the clinical teachers and satisfaction of their majors; 4.Among male nursing undergraduates,the total score of stress and most subscale(except working nature and working contents,employment)scores of stress were positively correlated with the negative coping styles.The scores of stress level was positively correlated with the scores of SCL-90,Negative coping styles was positively correlated with the scores of SCL-90 among male nursing undergraduates,while positive coping styles were inversly correlated with most subscales(except phobic,paranoia,psychoticism)scores of SCL-90. Conclusions： 1.25% male nursing undergraduates have a higher level of stress,which is from employment, profession,working nature and working contents,financial difficulties and so on.The coping styles adopted by male nursing undergraduates were mainly positive coping styles.The mental health of male nursing undergraduates were lower; 2.Different genders have significant differences between stressors, coping style and mental health; 3.Stress,coping style,satisfaction degree to clinical nursing teaching and the professional title of the clinical teachers are predietors of mental health among male nursing undergraduates.