Study on Agricultural Socialized Service System in Guangdong Province

This paper analyzed the current situation of the construction of agricultural socialized service system in Guangdong Province and summarizes five typical services,namely the public service," company + base + farmer "," company + research institute + base +farmer"," specialized cooperative + farmer",and " government + enterprise + farmer".In view of the existing problems in the construction of agricultural socialized service system in Guangdong Province,it came up with recommendations including making proper top level design,strengthening the construction efforts,actively cultivating service entities,improving the structure of information service system,and establishing and improving rural financial system.

Different Burial-Cooling History of Triassic Strata between the Western Weibei Uplift and the Northwestern Weihe Basin in Northwest China

Analysis of tectonothermal history of the Yanchang Formation in the western Weibei Uplift and in the northwestern Weihe Basin can reconstruct the cooling history of the southwest most remained Upper Triassic source rock of the North China Plate. Apatite fission-track(AFT) and(U-ThSm)/He(AHe) analysis were used to recover the cooling and uplift history of the Upper Triassic here. Ten sandstones from the Middle–Upper Triassic strata yield AFT ages between 179.8 ± 7.4 and 127.6 ± 8.1 Ma. AHe ages of two sandstones have the value of 37.7 ± 2.3–131.1 ± 8.1 and 45.7 ± 2.8–83.5 ± 5.2 Ma. Time-temperature modeling results showed that tectonothermal history of the Yanchang Formation was initially different in time-space relationships but then became almost identical through time followed by different cooling rate. Modeling results of the Triassic strata in the Qianyang area and the Yaojiagou area revealed three different uplift-cooling stages commencing in the Late Jurassic at ~165 Ma and in Early Cretaceous at ~110 Ma, respectively, both followed by first similar cooling histories to the Early Miocene at ~20 – 23 Ma and then different since the Late Miocene. Uplift-cooling rate since the Late Miocene at ~8 Ma were different between the Western Weibei Uplift and the Northwestern Weihe Basin. The timing, cooling-uplift rates of the Yaojiagou area, which was mainly controlled by movements related to the Liupanshan Mountains, the Qinling Orogens and the Weibei Uplift, had the earliest onset of uplift-cooling for the Upper Triassic series compared to other regions within the Weibei Uplift. Cooling paths for the Upper Triassic series became uniform regionally in the Early Cretaceous marking a key time for the tectonothermal evolutionary history of Upper Triassic series in the southwestern North China Plate.

C-dots assisted synthesis of gold nanoparticles as labels to catalyze copper deposition for ultrasensitive electrochemical sensing of proteins

We report an ultrasensitive protocol for electrochemical sensing using the hydroxyl-rich C-dots assisted synthesis of gold nanoparticles(C-dots@AuNP) as labels with copper depositon reaction. The C-dots catalyzing copper deposition reaction was implemented for the first time. We constructed a sandwich-type immunosensor on the chitosan modified glassy carbon electrode(GCE) by glutaraldehyde(GA) crosslinking, with C-dots@AuNP as biolabels. Copper was deposited on the catalytic surfaces of second antibody-conjugated C-dots@AuNP nanoparticles through CuSO_4-ascorbic acid reduction, because both C-dots and AuNPs could strongly catalyze the CuSO_4 and ascorbic acid to form Cu particles, which amplified the detection signal. Then the corresponding antigen was quantified based on simultaneous chemical-dissolution/cathodic-preconcentration of copper for insitu analysis using anodic stripping square wave voltammetry(ASSWV) directly on the modified electrode. Under optimized conditions, these electrodes were employed for sandwich-type immunoanaly sis, pushing the lower limits of detection(LODs)down to the fg mL^(-1) level for human immunoglobulin G(IgG) and cardiac troponin I(cTnI), a cardiac biomarker. These novel sensors have good stability and acceptable accuracy and reproducibility, suggesting potential applications in clinical diagnostics.

共轭链对噻咯电致化学发光效率的影响

噻咯衍生物是一类重要的杂环化合物,在发光二极管和电致化学发光(ECL)传感器方面具有潜在的应用前景.为了进一步获得增强ECL性能的噻咯衍生物,本文报道了两种噻咯-噻吩共聚物在湮灭和共反应物反应中的绝对和相对电化学发光效率.通过电位扫描和电位脉冲,利用电化学发光-电压曲线、电化学发光-时间曲线和电化学发光光谱法研究了其ECL机理,并讨论了共轭体系和空间位阻效应对ECL效率的影响.结果表明,自由基的稳定性和反应性是影响两种噻咯-噻吩共聚物ECL效率的两个主要因素.与噻咯-噻吩单体相比,噻咯-噻吩共聚物的ECL效率主要受空间位阻效应的影响.大多数电化学发光研究都使用[Ru(bpy)_(3)]^(2+)作为标准来测定ECL研究中的相对发光效率.考虑到[Ru(bpy)_(3)]^(2+)与其他发光团在自由基行为上的差异,本文测量绝对电化学发光效率,比相对发光效率更准确.

Structural and expressional analysis of a cDNA that expresses predominantly in rice stamens

The development of stamen is an important stage during the sexual reproduction in higher plants. Studying the genes that predominantly or even specifically expressed in stamens will aid in understanding the molecular mechanism of stamen development. The structure of a rice CHS-like gene (D5) which predominantly expressed in anthers has been analysized, showing high structural similarity with two other anther-specific genes (A1 and BA42) from Brassica napus. Northern analysis also reveals that the three genes share a similar expression pattern and that the expression of D5 may relate to the early development of pollens. It is concluded that D5, A1 and BA42 represent a group of diverged CHS-like genes which are related to stamen development.