Development of a sensitive fluorescent derivatization reagent 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC) and its application for determination of amino acids from seeds and bryophyte plants using high-performance liquid chromatography with fluorescence detection and identification with electrospray ionization mass spectrometry

A pre-column derivatization method for the sensitive determination of amino acids and peptides using the tagging reagent 1,2-benzo-3,4dihydrocarbazole-9-ethyl chloroformate (BCEOC) followed by high-performance liquid chromatography with fluorescence detection has been developed. Identification of derivatives was carried out by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS/MS). The chromophore of 2-(9-carbazole)-ethyl chloroformate (CEOC) reagent was replaced by 1,2-benzo-3,4-dihydrocarbazole functional group, which resulted in a sensitive fluorescence derivatizing reagent BCEOC. BCEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. The derivatives showed an intense protonated molecular ion corresponding m/z (M + H)(+) under electrospray ionization (ESI) positive-ion mode with an exception being Tyr detected at negative mode. The collision-induced dissociation of protonated molecular ion formed a product at m/z 246.2 corresponding to the cleavage of C-O bond of BCEOC molecule. Studies on derivatization demonstrate excellent derivative yields over the pH 9.0-10.0. Maximal yields close to 100% are observed with a 3-4-fold molar reagent excess. Derivatives exhibit strong fluorescence and extracted detzvatization solution with n-hexane/ethyl acetate (10:1, v/v) allows for the direct injection with no significant interference from the major fluorescent reagent degradation by-products, such as 1,2-benzo-3,4-dihydrocarbazole-9-ethanol (BDC-OH) (a major by-product), mono- 1,2-benzo-3,4-dihydrocarbazole-9-ethyl carbonate (BCEOC-OH) and bis-(1,2-benzo-3,4-dihydrocarbazole-9-ethyl) carbonate (BCEOC)(2). In addition, the detection responses for BCEOC derivatives are compared to those obtained with previously synthesized 2-(9-carbazole)-ethyl chloroformate (CEOC) in our laboratory. The ratios AC(BCEOC)/AC(CEOC) = 2.05-6.51 for fluorescence responses are observed (here, AC is relative fluorescence response). Separation of the derivatized peptides and amino acids had been optimized on Hypersil BDS C-18 column. Detection limits were calculated from 1.0 pmol injection at a signal-to-noise ratio of 3, and were 6.3 (Lys)-177.6 (His) fmol. The mean interday accuracy ranged from 92 to 106% for fluorescence detection with mean %CV < 7.5. The mean interday precision for all standards was < 10% of the expected concentration. Excellent linear responses were observed with coefficients of > 0.9999. Good compositional data could be obtained from the analysis of derivatized protein hydrolysates containing as little as 50.5 ng of sample. Therefore, the facile BCEOC derivatization coupled with mass spectrometry allowed the development of a highly sensitive and specific method for the quantitative analysis of trace levels of amino acids and peptides from biological and natural environmental samples. (c) 2005 Elsevier B.V. All rights reserved.

一个先进的工业机器人计算机控制系统——ARCS

随着工业机器人及其应用的不断发展,要求一个强有力的计算机系统来控制它的工作,并具有灵活、方便的机器人编程语言.本文系统地介绍了我们自行设计并实现的一个先进的机器人控制系统——ARCS.该系统主要包括两部分:(1)一个实时多任务的机器人控制软件SVAL系统,该系统支持一种通用性较强的机器人编程语言——SVAL语言.(2)一个支持该软件系统工作的、具有开放式结构的硬件环境.ARCS系统具有良好的实时性、可扩展性及基于外部传感器信号进行控制的能力.由于该系统的开放式结构.使其根据不同要求可方便地增删其功能,并可控制不同类型的机器人.我们已成功地实现对PUMA760机器人的控制,并在其上引入了力觉与接近觉的传感器,采样时间可缩短到16ms.一年多的运行结果证明,该系统稳定可靠,性能良好,现在正向产品转化.

DAS24-3B数据采集系统控制系统软件的研制与开发

Under the auspices of the 'knowledge-Innovation Program' of CAS, Institute of Geology and Geophysics has established the Broadband Seismic Laboratory. A new kind of 24-bit high-resolution seismograph DAS24-3B has been designed and manufactured in an effort of developing China's own technology of seismic array. Since these instruments will primarily be used in field operation, there is a need to optimize the system software of data acquisition system (DAS) to enhance its stability, compatibility and maintenance. The design ideas of the system software of DAS24-3B are partly learned from the advanced DAS 72A-08. In this system there are two exclusive communication programs DNAPI-COM1 and DNAPI-LPT1, which are suitable for all standard industrial computers with ECP parallel port and serial port. By these exclusive parallel and serial communication interface the system software is split into three parts, acquisition program, user's control program and graphical display program, which can function well in separate units and can run correctly in whole. The three parts of DAS24-3B's system software possess different functions and advantages. The function of acquisition program is to control the process of seismic data acquisition. DAS24-3B system reduced its power and harddisk read-write disturbance by using the extended memory attached to its CPU, which functions as enlarging the data buffer of system and lessening the times of harddisk read-write operations. Since GPS receiver of DAS is strongly sensitive to the around environment and has the possibility of signal loss the acquisition program has been designed with the ability to automatically trail the GPS locked time. The function of user's controlling program is to configure the system's work environment, to inform the user's commands to DAS, to trail the status of DAS in real-time. The function of graphical display program is to illustrate data in figures, to convert data file into some common formatted file, to split data file in parts and combine data files into one. Both user's control program and graphical display program are API (Application Programming Interface) in window 95/98 system. Both possess the features of clearness and friendship by use of all kind of window controls, which are composed by menu, toolbar, statusbar, dialogue box, message box, edit box, scrollbar, time control, button and so on. Two programs of systemic exception handles are provided to treat the trouble in field. The DAS24-3B DAS has been designed to be easier to use-better ability, more stable and simpler. It has been tested in field and base station and has been proved more suitable for field operation of seismic array than other native instruments.

交易型领导的结构和作用机制研究

The Multifactor Leadership theory developed by Bass (1985) has become the new paradigm of leadership research. The empirical results of the effectiveness of transformational and transactional leadership in the literature, however, are not consentient. Researchers in China found the different structure of transformational leadership, but have not developed the transactional leadership. This study attempts to investigate three key questions in the unique Chinese socio-economic context: 1) what is the structure of transactional leadership in China? 2) What are the differences between western countries and China? And 3) what is the relationship between the transformational and transactional leadership mechanism? This study examines data collected from 3,500 participants, using Explored Factor Analysis (EFA), Confirmed Factor Analysis (CFA), Hierarchical Regression Analyses, partial correlations and other statistics methods. The major finings are listed as follows： Firstly, inductive methods was used to explore the structure of transactional leadership and the result show that transactional leadership is a four dimensions structure which includes contingent reward, contingent punishment , process control and anticipated investment. Reliability analysis, item analysis, EFA and CFA show the reliability and validity of the transactional leadership questionnaire we designed is good enough, the design of the item is effectively and properly. Contrast to other researches, anticipated investment emphasis on the leader’s recessive investment for subordinate, and this kind of transaction is quite special under the Chinese culture. While the content of the contingent reward with the contingent punishment is wider than the contingent reward in the western country, and the process control is wider than the management by exception and including goal setting and the management during the process. Secondly, hierarchical regression analyses showed that transformational and transactional leadership were significant positively related with in-role performance, extra-role performance, satisfaction and leadership effectiveness while negatively related to intention to leave. The effects of transactional and transformational leadership are different. Transactional leadership could significantly predict intention to leave controlling for transformational leadership, while transformational leadership could significantly predict in-role performance, extra-role performance, satisfaction and leadership effectiveness controlling for transactional leadership. Thirdly, the income level and the rank of subordinates are the moderators between the transformational, transactional leadership and leadership effectiveness. The leadership effectiveness of transactional leadership would decrease as the rank of subordinates increased, while the leadership effectiveness of transformational leadership would increase as the rank of subordinates increased. Transactional leadership is positively related to the effectiveness when the level of the subordinate income is low, but negatively related to the effectiveness when the level of the subordinate income is high. However the income level of the subordinate could not influence the leadership effectiveness of transformational leadership.

中学生的性别—理科刻板印象及其影响因素

Gender stereotype has a great effect on an individual’s cognition and behavior. Notably, stereotyped cognition about gender and science exerts an influence on an individual’s academic or career choice. In order to weaken the negative effect of gender-science stereotype and facilitate girls’ participation in science, this study examined the development of implicit gender-science stereotype and influence factors with implicit association test and questionnaires in a sample of secondary school students. The present work showed that: Firstly, there were no gender differences and gender predominance in performance of math and physics during secondary school years. However, girls tended to attribute success in math and physics to unstable factors, or the failure to stable factors. The reverse was true for boys’ attribution. This gender difference in attribution was especially evident in their study of physics. Secondly, 7th to 11th grade students implicitly regarded science as male domain, with the exception of 7th grade boys, who thought both boys and girls can study science well. On the whole, this gender-science stereotype was more and more evident as the specialization of science subjects’ progresses through secondary school, and this inclination decreased with increasing grade. Thirdly, the negative correlation between explicit and implicit stereotype which appeared in girls from 8th grade grew stronger with increasing grade and became significant in 10th grade. On the contrary, the significantly positive correlation existed in 7th -11th boys. Fourthly, the experience including attitude toward science, science interests and self –efficacy in math and physics had significantly negative effect on girls’ implicit gender-science stereotype, and significantly positive effect on boys’. It was showed that gender moderated the effect of experience in the study of science and implicit gender-science stereotype, and the attitude toward science mediated the relationship between science interests, self-efficacy and implicit gender-science stereotype. Fifthly, the perceived teacher’s class behaviours by students and the perceived parents’ gender stereotype by children had strong predictive power on students’ implicit gender-science stereotype. And the perceived teachers’ and parents’ performance expectancies can influence gender-science stereotype indirectly through self-efficacy in related subjects and attitude toward science. In conclusion, the present study showed that cognitive bias about gender and science existed in Chinese secondary school students. The information conveyed from teachers and parents interacting with students’ experience in the study of science affect the formation of stereotyped cognition.