Comparative quantitative structure–activity relationship (QSAR) study on acute toxicity of triazole fungicides to zebrafish

We employed two-dimensional quantitative structure–activity relationship (2D-QSAR) and hologram QSAR (HQSAR) methods to quantitatively investigate the mechanism and active site of toxicity for Danio rerio exposed to triazole fungicides. Our results showed that 2D-QSAR models constructed using the energy of the lowest unoccupied molecular orbit, the net C atom charges, the octanol–water partition coefficient and the molecular shape factor had higher predictive abilities. HQSAR models containing the fragment distinctions atoms (As), bonds (Bs), chirality (Ch) and donors and acceptors (D&A) had higher reliability. It was found that 2D-QSAR results explaining the toxicity mechanism were consistent with HQSAR. In summary, the hydrophobicity and shape/size of the molecule were the important factors influencing the toxic effect of these chemicals against D. rerio. In addition, electron exchange may occur between these fungicides and the target. The study provided a method to evaluate the environmental risk of chemicals with a similar structure, based on the QSAR models obtained.     

3GY型粉体无尘装车机的开发与应用

应用自主知识产权,采用“密闭输送、最小落差、零匝输送、软连接和科学运行管理”技术,科学组合,研究开发成功粉体无尘装车机,科学消除了高温,高压、高料位条件下贮仓放料,常规除尘器出灰和粉体转输与装车的粉尘污染与资源流失。     

Potential shift of bacterial community structure and corrosion-related bacteria in drinking water distribution pipeline driven by water source switching

• Bacterial release from aged pipe sections under extreme conditions was quantified. • Released bacterial community structure exhibited large variation after transition. • Risks from transition reduced significantly with cleaner source. As a result of pollution in the present water sources, cities have been forced to utilize cleaner water sources. There are few reports regarding the potential shift of bacterial community structure driven by water source switching, especially that of corrosion-related bacteria. Three types of finished water were used for simulation, the polluted source water from the Qiantang and Dongtiaoxi Rivers (China) was replaced by cleaner water from Qiandao Lake (China). Here, we discussed the transition effects through three simulated reactors. The bacterial characteristics were identified using the high-throughput sequencing and heterotrophic plate count method. It was observed that the level of culturable bacteria declined by 2–3 orders of magnitude after water source switching. The bacterial community released from the pipeline reactor was significantly different under different finished water, and it exhibited large variation at the genus level. Porphyrobacter (58.2%) and Phreatobacter (14.5%) clearly replaced Novosphingobium, Aquabacterium, and Cupriavidus as new dominant genera in system A, which could be attributed to the lower carbon and nitrogen content of the new water source. Although corrosion-inhibiting bacteria decreased after switching, they still maintained dominant in three reactors (6.6%, 15.9%, and 19.7%). Furthermore, potential opportunistic pathogens such as Sphingomonas were detected. Our study shows that after transition to a high quality water source, the total culturable bacteria released was in a downtrend, which leads to a great reduction in the risk of bacterial leakage in the produced drinking water.     

苯并[a]芘和1-羟基芘诱导人胚胎干细胞分化心肌细胞ROS、CYP基因表达和DNA损伤

多环芳烃(PAHs)化合物中的苯并[a]芘和PAHs暴露检测标志物1-羟基芘与心脏功能障碍有关,但其生物学机制尚不清楚。为研究苯并[a]芘和1-羟基芘对心脏的毒性作用,基于人胚胎干细胞分化心肌细胞(hESC-CM)研究了苯并[a]芘和1-羟基芘对心肌细胞活性氧(ROS)生成、CYP基因表达和DNA损伤等的影响。结果表明,苯并[a]芘和1-羟基芘对h ESC-CM活性无影响,但能显著增强细胞ROS水平,诱导DNA损伤。此外,苯并[a]芘还能诱导细胞线粒体促凋亡基因的表达。研究表明,苯并[a]芘和1-羟基芘能通过诱导氧化应激和DNA损伤事件导致h ESC-CM损伤,在一定程度上解释了多环芳烃暴露导致心脏疾病的分子机制。     

浅谈安全管理科学的方法──安全生产科学管理十八法

安全生产科学管理方法是，安全管理科学的重要组成部分。对十八种方法的内容与特点进行了阐述，并结合当前实际情况，从全面质量管理、安全系统工程、人机工程、行为科学等方面进行了探讨。     

酪氨酸氯化过程中光谱变化特征及消毒副产物的生成规律

考察酪氨酸在不同投氯量条件下氯化后的余氯,紫外吸光度值和荧光光谱,以及消毒副产物对羟基苯乙腈(4-HBC)的生成特性。结果表明,随着投氯量的增加,余氯呈现先增加再减小再增加的趋势。在投氯量为0～0.5 mmolCl2/L时,增加投氯量可提高氯化后溶液的UV254、UV274和UV280值以及4-HBC的生成量,表明低投氯量时氯化可提高溶液中不饱和键的含量;而投氯量为0.5～1 mmol Cl2/L时,增加投氯量降低UV254、UV274和UV280值以及4-HBC的生成量,表明过量的氯亦可破坏溶液中的不饱和键。荧光光谱测试实验亦发现:在投氯量为0.05 mmol Cl2/L时,酪氨酸溶液氯化后的荧光峰强度明显增加,表明氯化可生成荧光强度较高的产物。过量的氯(0.5～1 mmol Cl2/L)则可破坏溶液中的荧光结构,降低荧光峰强度直至未检出。     

Organizational commitment,supervisory commitment,and employee outcomes in the Chinese context: proximal hypothesis or global hypothesis?

This study examines the relationship between organizational commitment and supervisory commitment (commitment to supervisor) in terms of their effects on employee outcomes in the Chinese context. Based on the principle of compatibility, we hypothesized that organizational commitment and supervisory commitment served as logical mediators (global hypothesis and proximal hypothesis) for predicting organization‐relevant and leader‐relevant outcomes respectively. Moreover, because of the impact of personalism in Chinese culture, we predicted that supervisory commitment also significantly influenced organization‐relevant outcomes, in addition to its effect on leader‐relevant outcomes. Two separate questionnaires were administered to 538 subordinates and their supervisors in Taiwanese companies. Structural equation modeling and hierarchical block regression analysis shows that the principle of compatibility and personalism can explain the proposed relationship in this study. Implications and research directions are discussed in light of Chinese culture for future investigation into organizational commitment and supervisory commitment. Copyright © 2003 John Wiley & Sons, Ltd.     

当代大学生就业难的道德困境

在当前社会主义市场经济环境下，如何引导好大学毕业生树立正确的就业观，如何平衡功利主义与责任意识、享乐思想与奉献精神之间的关系，如何在企业需求与学校人才培养模式之间形成良性互动，是当前大学教育工作面临的重要课题。充分调动政府、社会、企业、学校各自资源的力量，是解决当代大学生就业困境的重要出路。     

德育方法探究

德育方法的正确实施，是提高德育效果的重要环节。在对学生进行品德教育的过程中，教师可通过综合教育法、精讲教学法、互动式教学法和实践教学法的有效实施，来提高学生学习的积极性，提高学生的表达能力和自我教育能力，并实现促进学生知行统一的教育教学目标。     

从汶川地震看危机管理人才的能力

本文在分析地震危机事件特征以及管理人才在汶川地震的抗震救灾过程中的作用的基础上,总结出危机管理人才的素质及能力要求,并试探着提出培养和提高管理人才危机管理能力的途径.