Capillary gas chromatographic determination of dimethachlon residues in fresh tobacco leaves and cut-tobacco

Simple procedures for extraction and chromatographic determination ofdimethachlon residues in fresh tobacco leaves and cut-tobacco are described. The determination was carried out by capillary gas chromatography （GC） with electron capture detection （ECD） and confirmed by GC-MS. The mean recoveries and relative standard deviation （RSD） were 93.2%-112.9% and 3.5%-6.7%, respectively at levels ranging from 0.01 to 0.1 mg/kg. The limit of determination was 0.001 mg/kg. Tobacco samples in routine check were successfully analyzed using the proposed method.     

Aroma changes of black tea prepared from methyl jasmonate treated tea plants

研究目的：为茉莉酸甲酯诱导来提高茶叶香气品质提供理论依据,为新型花香红茶的研制提供技术支持。创新要点：首次将茉莉酸甲酯应用于诱导茶叶香气品质提高,初步验证了茶叶香气品质提高的本质原因：相关酶活性提高,基因表达上调。研究方法：采用顶空固相微萃取法（HS-SPME）对红茶香气进行富集,气相色谱-质谱联用仪（GC-MS）进行解吸附分析,实时定量多聚酶链式反应（qRT-PCR）分析茶鲜叶中香气相关酶基因表达。重要结论：茉莉酸甲酯诱导后的茶鲜叶中多酚氧化酶（PPO）活性上升,β-葡萄糖苷酶活性下降;PPO和β-樱草糖苷酶基因表达上调,β-葡萄糖苷酶基因表达下调。茉莉酸甲酯诱导后的茶鲜叶能明显提高由其制成的红茶香气品质,且萜烯醇类和萜烯类含量明显提高。     

Preparation of high-affinity rabbit monoclonal antibodies for ciprofloxacin and development of an indirect competitive ELISA for residues in milk

A convenient competitive enzyme-linked immunosorbent assay (ELISA) for ciprofloxacin (CPFX) was developed by using rabbit monoclonal antibodies (RabMAbs) against a hapten-protein conjugate of CPFX-bovine serum albumin (BSA). The indirect competitive ELISA of CPFX had a concentration at 50% inhibition (IC₅₀) of 1.47 ng/ml and a limit of detection (LOD) of 0.095 ng/ml. The mAb exhibited some cross-reactivity, however, not so high with enrofloxacin (28.8%), ofloxacin (13.1%), norfloxacin (11.0%), fleroxacin (22.6%), and pefloxacin (20.4%). And it showed almost no cross-reactivity with other antibiotics or sulfonamides evaluated in this study. The competitive ELISA kit developed here could be used as a screening tool to detect and control illegal addition of CPFX in food products. This kit had been applied to milk detection and the recovery rates from samples spiked by CPFX were in a range of 63.02%–84.60%, with coefficients of variation of less than 12.2%.     

十九世纪四五十年代华茶出口贸易缘何形成黄金期

我国以“茶的故乡”已久享盛名,然而至十九世纪的四五十年代才形成了华茶出口的黄金期。华茶出口所以如此兴盛,有国际和国内两个层面的原因,具而言之,有政策方面的因素,亦有供求关系方面的影响。     

有机磷及氨基甲酸酯类农药残留现场检测方法可靠性研究

参照国标GB／T5009．199-2003《蔬菜中有机磷和氨基甲酸酯类农药残留量的快速检测法》，对现场残留农药测定仪的仪器精密度以及检出限进行了测定，并分析了该仪器对各种农药的最小检测浓度。发现该仪器对部分农药。如敌敌畏、呋喃丹、速灭威以及残杀威有很好的检出灵敏度，但对甲胺磷的检出灵敏度最差；同时环境温度对检测结果也有一定的影响。因此。在规范实验操作的前提下，对不同的农药选择最合适的方法，才能保证检测数据的准确性和可靠性。     

基于毒品层析试条定量测试仪的研究

阐述了MOR层析试条测试仪的基本结构、工作原理以及光电传感器的设计。实验表明，用该仪器对免疫层析试夺进行定量检测是可能的。     

商洛茶叶中痕量锰催化光度法测定

茶叶中含有痕量锰,采用Mn(Ⅱ)—甲酚红—氨三乙酸—NH3.H2O—KIO4体系进行催化氧化光度法测定,灵敏度可达6.1×10-10g/mL,选择性高,常见的二十余种阴、阳离子均无干扰,结果重现性好.结果表明,商洛出产的几种茶叶含锰量均略高于被测试的几种外地茶叶.     

计算主族元素Sm~的新方法

应用灰色理论中的等时空距灰色模型GM（1,1）研究了主族元素标准熵（Sm（?））和周期间的关系,所建模型对20种主族元素标准熵（Sm（?））的计算结果和文献报导值与实验测定结果进行了比较,新建模型求得Sm（?）值与实验测定结果之间的绝对平均差为1.807,标准偏差为1.736,明显优于已有文献报导结果（绝对平均值差和标准偏差分别为2.748和2.195）.利用所建模型预言了113号元素（ununtrium,Uut）、114号元素（Ununquadium,Uuq）、119号元素（ununennium,Uue）、120号元素（unbinilium,Ubn）以及阶和Ra的Sm（?）.它们分别是85.96,97.75,120.04,97.38,102.08,78.88 kj/mol.     

Validation of the use of foreign gas rebreathing method for non-invasive determination of cardiac output in heart disease patients

INTRODUCTION In the arsenal of cardiac functional parameters,cardiac output(CO),cardiac index(CI),and strokevolume(SV)are potentially important determinantsof hemodynamics,the measurement of which relieson complicated and sometimes invasive techniques.In the case of congestive heart failure,non-invasivemethods to provide accurate measures of these pa-rameters during exercise stress testing would addsignificant objectiveness to the test result.This couldbe of considerable importance for …     

解非对称线性方程组最小剩余法的改进

In this paper, the minimal residual （MRES） method for solving nonsymmetric equation systems was improved, the recurrence relation was deduced between the approximate solutions of the linear equation system Ax = b, and a more effective method was presented, which can reduce the operational count and the storage.     

White women speak,black women write: the politics of locution and location in the other researching the not other

This paper scrutinizes a rare methodological moment when I found myself, an unseasoned black woman scholar, researching the lives of three white women. In this reflective process, I make a single point: that the locution of race is limiting if it persists in being a point of struggle for marginalized scholars. In so doing, I distinguish between race as the site of intellectual engagement and race as a point from which to engage in scholarship. I begin with a brief explanation of how I came to take the decision to research three white women and of (dis)locating myself as other to the respondents. I then examine my actions in the context of concerns raised by other black scholars in their engagement with the academic establishment. Finally, I draw on the works of feminist scholars and argue that politicized and strategic understandings of otherness can potentially create challenging means for intellectual activism.     

气相中前过渡金属正离子乙炔络合物M(C2H2)+(M=Sc,Ti,V)的振动频率计算分析

采用密度泛函(DFT)计算方法,在UB3LYP/6-311 G(3d,2p)水平上优化了过渡金属正离子乙炔络合物M(C2H2) (M=Sc,Ti,V)不同自旋态的稳定几何构型,并对此络合物体系的全部振动频率进行了计算和全面分析。结果表明,能量较低的高自旋态M 与C2H2在形成络合物时,M 的价电子要发生翻转,形成稳定的低自旋态络合物。根据频率分析,所计算的振动频率值反映出低自旋态络合物比高自旋态络合物有较强的M-C键,在形成低自旋态络合物的同时,过渡金属正离子M 已活化了乙炔的C-C三键和C-H键。     

Effective and inexpensive gas chromatography method for detection of trace level SO2 in H2 fuel

Gas chromatography （GC） analysis of sulfer dioxide is challenging because SO2 is a highly mobile and chemically active molecule. For the conventional GC method with flame photometric detector （FPD） and direct-injection, it is often ineffective particularly when the SO2 level is as low as on the trace level. In this paper, a modified GC system integrated with an adsorption-desorption device was developed to detect the trace SO2 impurity in H2 fuel. Adsorbent GDX-502 is used in the adsorber to adsorb/collect SO2 from the sample gas and desorb/release it in a concentrated flow so that the conventional GC at downstream could detect it with an acceptable accuracy.     

Reconstruction method of differentiated backprojection-projection onto convex sets in the interior problem and design of bone-nail model

This work focuses on the application of the reconstruction method of differentiated backprojection （DBP）-projection onto convex sets （POCS） in the interior problem.First,we present the definition of the interior problem and real truncated Hilbert transform,and then outline the implementation steps of DBP-POCS.After that,we introduce the middle-part known condition for region of interest （ROI） accurate reconstruction and the unique condition of the interior problem,and verify the uniqueness and stability of the interior problem accurate reconstruction through numerical experiments,and then compare the results for the interior problem in reconstruction images using filtered backprojection （FBP）.In addition,the authors also design the application models of ROI reconstruction and make an initial attempt to the application of DBP-POCS method in the interior problem.     

Performance of biological phosphorus removal and characteristics of microbial community in the oxic-settling-anaerobic process by FISH analysis

Performance of biological phosphorus removal in the oxic-settling-anaerobic （OSA） process was investigated. Cell staining and fluorescent in situ hybridization （FISH） were used to analyze characteristics and microbial community of sludge. Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus （TP） contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms （PAOs）. FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria.     

结构钢中残余镍、铬、铜的联合测定分析方法研究

试样用盐—硝混酸溶解,在盐酸（１％）介质中加氯化铵溶液抑制铁对铬的干扰,在同一份试样中分别测定镍、铬、铜．     

Seven keys for implementing the self-evaluation,periodic evaluation and accreditation (AVA) method,to improve quality and student satisfaction in the Italian higher education system

This paper develops a theoretical framework that could facilitate the application of the Autovalutazione, Valutazione periodica, Accreditamento (AVA) method in Italian universities, trying to simplify the use of this approach, and to cover the existing gap between Italy and others European academic institutions. The new competitive environment in the academic system has created a reality where customers compare the ‘knowledge value’ that they are likely to receive in each academic institution. Quality in education is nowadays fundamental and student satisfaction is one of its main dimensions. There is an emphasis on service that meets the students’ needs and expectations, problem-solving processes based on facts, feedback systems and statistical methods and improvement of processes and systems by collaboration and involvement. Starting from 2013, all Italian universities are obliged by law to adopt the AVA method [Self-Evaluation, Periodic Evaluation and Accreditation], a system of activities carried out by the National Agency for the Evaluation of Universities and Research Institutes (ANVUR).     

MGB probe assay for rapid detection of mtDNA11778 mutation in the Chinese LHON patients by real-time PCR

Objective:Leber's hereditary optic neuropathY (LHON)is a maternally inherited degeneration of the optic nerve caused by point mutations of mitochondrial DNA(mtDNA).Many unsolved questions regarding the penetrance and pathophysiological mechanism of LHON demand efficient and reliable mutation testing.This study aims to develop a minor groove binder(MGB) probe assay for rapid detection of mtDNA11778 mutation and heteroplasmy in Chinese LHON patients by real-time polymerase chain reaction(PCR).Methods:Forty-eight patients suspected of having LHON and their maternal relatives underwent a molecular genetic evaluation,with 20 normal individuals as a control group at the same time.A real-time PCR involving two MGB probes was used to detect the mtDNA 11778 mutation and heteroplasmy.A linear standard curve was obtained by pUCmLHONG and pUCmLHONA clones.Results:All 48 LHON patients and their matemal relatives were positive for mtDNA 11778 mutation in our assay,27 heteroplasmic and 21 homoplasmic.Eighteen cases did not show an occurrence of the disease,while 9 developed the disease among the 27 heteroplasmic mutation cases.Eleven did not show an occurrence of the disease,while 10 cases developed the disease among 21 homoplasmic mutation cases.There was a significant difierence in the incidence between the heteroplasmic and the homoplasmic mutation types.The time needed for running a real-time PCR assay was only 80 min.Conclusion:This real-time PCR assay is a rapid,reliable method for mtDNA mutation detection as well as heteroplasmy quantification.Detecting this ratio is very important for predicting phenotypic expression of unaffected carriers.     

20世纪中国教育学发展之镜鉴

20世纪中国教育学经历了四个阶段,即启蒙教育学阶段、救亡教育学阶段、意识形态教育学阶段和非意识形态教育学阶段。从共时态的角度来看,教育学是否是一门科学的追问一直响彻20世纪;教育学基本理论何以存在的探求一直在代代教育学者群中构成追问。因此,如何使我国传统教育思想的“因子”在引介西方教育思想的背景下得到激活是20世纪中国教育学发展的再一主题。     

元朝国子学生员问题探析

元朝国子学是元朝中央官学之一。在国子学中实际就读的生员基本上可分为国子生、伴读和陪堂生三种。其中,国子生和伴读是享有官给廪饩的公助生,而陪堂生则是不享有官给廪饩的自费生。对这些学生的入学资格从入学年龄、民族构成、生员人数、入学身份等方面都有明确而具体的规定;国子学生员的仕途主要有岁贡和科举两条途径。