Picosecond rotational diffusion by differential single-photon fluorescence spectroscopy

The rotational diffusion contants of rhodamine-6G, coumarin-1 and N-acetyltryptophanamide in various solvents have been determined by an experimental method where the vertically and horizontally polarized fluorescence spectra are measured simultaneously by the same detector. The results indicate that the Debye—Stokes—Einstein model does not hold for coumarin-1 and N-acetyltryptophanamide in ethylene glycol.     

A new approach to detect a set of SNP-SNP markers: Combining ARMS-PCR with SNaPshot technology

Microhaplotypes are a new promising type of forensic genetic marker. Without the interference of stutter and high mutation rates as for STRs, and with short amplification lengths and a higher degree of polymorphism than single SNP, microhaplotypes composed of two SNPs, SNP–SNP, have a strong application potential. Currently, the most common method to detect microhaplotypes is massive parallel sequencing. However, the cost and extensive use of instruments limit its wide application in forensic laboratories. In this study, we screened 23 new SNP–SNP loci and established a new detection method by combining a multiplex amplification refractory mutation system-based PCR (ARMS-PCR) and SNaPshot technology based on CE. First, we introduced an additional deliberate mismatch at the antepenultimate base from the 3′ end of primers when designing ARMS-PCR for SNP 1 (the first SNP of the SNP–SNP). Then, single base extension primers for SNaPshot assay were designed next to the position of SNP 2 (the second SNP). Finally, 15 loci were successfully built into four panels and these loci showed a relatively high level of polymorphism in the Southwest Chinese Han population. All the loci had an average probability of informative genotypes (I value) of 0.319 and a combined discrimination power of 0.999999999. Therefore, this new detection system will provide a valuable supplement to current methods.     

Metal Concentrations in Soils and Sediments in Southwest Louisiana

ABSTRACT

Soils and sediments represent concentrated reservoirs for metals that serve as sinks for introduced trace metals or can become environmental sources. The coastal zone of Louisiana provides a “living laboratory” to investigate the mechanisms of transport, deposition, and dissolution of trace metals into this fragile environment. Common trace metals determined and their range of concentrations in soil and sediments are chromium (10-30 (parts per million) (ppm)), copper (10-25 ppm), iron (0.6-2.1 %), manganese (200-600 ppm), nickel (6-20 ppm), lead (8-20 ppm), and zinc (30-55 ppm).     

Design,synthesis and SAR study of novel sulfonylurea derivatives containing arylpyrimidine moieties as potential anti-phytopathogenic fungal agents

Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy.The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities.Based on the preliminary fungicidal activities,a CoMFA model was constructed and the 3 D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities.In order to study interaction mechanism,10 k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities.It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS.Thus,the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphyt o pathogenic fungal agents.     

基于拉曼光谱的储层沥青热演化特征及其判别

为了明确储层沥青热演化程度与激光拉曼光谱的关系,利用拉曼光谱无损分析和流体包裹体方法,对黔西南白层地区储层沥青拉曼光谱进行了定量化描述,首先获取了储层沥青其伴生流体包裹体均一温度,然后获得了储层沥青拉曼光谱图,并对比标准沥青成熟度分布图,确定了储层沥青热演化程度及其特征.结果表明:黔西南白层地区存在晚三叠世(230 M...     

矢志照亮全中国——徐叙瑢院士访谈录

通过对徐叙瑢院士读书、教学、科研几个方面的访谈,从求学西南联大、留学苏联、开展发光学研究等几个阶段,反映其献身科学与教育的人生历程与卓越贡献.     

西南科技大学科技中心南侧滑坡成因分析及稳定性评价

通过对西南科技大学科技中心南侧滑坡工程地质条件及滑坡发育特征的研究,分析滑坡的形成机制,并运用传递系数法进行滑坡稳定性评价,表明该滑坡在天然状态下处于不稳定~暂时稳定状态。为保证校区E道路的正常运行及拟建科技中心的安全,本文提出了采用抗滑桩及挡土墙为主,辅以地表、地下排水工程等综合治理方案。     

耐温抗盐AM-AA-SAS-St四元聚合物驱油剂的合成及性能评价

本文采用乳液聚合方法,以丙烯酰胺、丙烯酸、烯丙基磺酸钠和苯乙烯作为单体,过硫酸铵-亚硫酸氢钠为氧化还原引发剂,合成了一种新型耐温耐盐的四元共聚物,并对其结构进行了红外、核磁共振及元素分析表征。考察了温度、单体浓度、体系pH和引发剂浓度等条件对聚合物表观粘度的影响,并确定了最佳的合成条件,同时对其抗老化、耐温及耐盐性能进行了评价。结果表明,该四元共聚物具有良好的耐温抗盐性能;另外,聚合物的岩心流动实验表明该四元共聚物具有较好的波及效率及出色的驱油效果,可以用作提高采收率的聚合物驱油剂。     

台西南盆地构造特征与演化

通过对南海973航次在该区域的多道地震剖面的解释,并结合重力和磁力资料,发现台西南盆地的主要构造走向为NE-NEE向,沉积上具有独特的双层构造,是一个与南海演化密切相关的新生代伸展型断陷盆地.这个盆地早第三纪开始发育,形成了大量的正断层和由它们控制的一系列半地堑,发育了古新世-渐新世的沉积.渐新世末期盆地受到挤压作用影响,发育了一系列的逆冲断层和反转构造,表明了台西南盆地"先张后挤"的演化特征,从中新世开始进入热力学沉降坳陷发育阶段.     

Changing characteristics and spatial differentiation of spring precipitation in Southwest China during 1961-2012

In this study,we analyze spring precipitation from 92 meteorological stations spanning between 1961 and 2012 to understand temporal-spatial variability and change of spring precipitation over Southwest China.Various analysis methods are used for different purposes,including empirical orthogonal function(EOF) analysis and rotated EOF(REOF) for analyzing spatial structure change of precipitation anomaly,and the Mann-Kendall testing method to determine whether there were abrupt changes during the analyzed time span.We find that the first spatial mode of the precipitation has a domain uniform structure;the second is dominated by a spatial dipole;and the third contains five variability centers.The 2000 s is the decade with the largest amount of precipitation while the 1990 s is the decade with the smallest amount of precipitation.The year-to-year difference of that region is large:the amount of the largest precipitation year doubles that of the smallest precipitation year.We also find that spring precipitation in Southwest China experienced a few abrupt changes:a sudden increase at 1966,a sudden decrease at 1979,and a sudden increase at 1995.We speculate that the spring precipitation will increase gradually in the next two decades.