有机磷农药在水生态系中生物净化机理研究 4. Pseudomonas sp. CTP-01 的对硫磷水解酶诱导合成性质

Pseudomonas sp.CTP-01的对硫磷水解酶具有底物诱导合成性质。停滞生长期的细胞接触底物半小时即产生相应酶的合成,而指数生长期的细胞接触底物48小时后才发生酶的合成。甲基对硫磷及对硝基酚也具有诱导作用,可见合成对硫磷水解酶的诱导特异基团可能与对硝基酚及其苯环上的取代基有密切关系。       

东湖富营养水体中藻菌异味性次生代谢产物的研究

以自制的开环吹脱捕捉（ＯＬＳＡ）装置富集东湖营养水的藻菌异味性次生代谢产物,并对这些化合物进行鉴定和周年测,同时计数水样中的藻、菌生物量。研究发现,东湖水体产生“土霉味”的主要成分为２－甲基异茨醇（ＭＩＢ）,它来源于席藻和放线菌的次生代谢,其随季节变化的规律为一年有５个高峰期,即１月、４月和９月;并且,ＭＩＢ的浓度与水体富营养化程度以及席藻和放线菌的生物量呈正相关。     

六六六在水环境中转移、积累和归趋研究——3.六六六在鱼体的积累释放

鳃是六六六进入鱼体的主要通道,鱼体的残留水平决定于水与体脂间的分配平衡。要使背肌六六六残留低于0.5毫克/公斤,则水中六六六含量要低于0.024毫克/升。鱼体六六六残留向水体释放的速度与温度有关,温度低,释放慢;当温度低于10℃时,释放的速度极慢以至难以检出。建议采用清水寄养的方法,让鱼体释放六六六,降低残毒,提高商品质量。这种方法估计也适用于其它脂溶性的与水分配系数不是太大的污染物。       

灭幼脲Ⅲ号在好气水环境中的降解代谢的初步研究

本文研究了新农药灭幼脲Ⅲ号在好气水环境中的降解与代谢。在避光条件下,观察了灭菌组与实验组中灭幼脲Ⅲ号及其主要代谢产物的消长过程,比较了它的化学水解与微生物降解的差异。在室内模拟好气系统中,研究了母体化合物在水体中的残留动态和生物降解半衰期,及其初期主要代谢途径的转化产物,同时分别用高效液相色谱法,紫外吸收光谱扫描,以及特征有机质谱图,对灭幼脲Ⅲ号的两种主要代谢产物进行了定性定量测定。结果表明:灭幼脲Ⅲ号在室内好气环境中较易水解,而且水中微生物的存在能加速它的降解,母体化合物在水体中初期代谢主要途径为分子中的苯甲酰碳与脲氮键首先开裂,生成邻氯苯甲酸(CBA)和对氯苯基脲素(CPU)。     

Highly Sensitive Plasmonic Sensor Based on Fano Resonance from Silver Nanoparticle Heterodimer Array on a Thin Silver Film

We investigate the optical spectrum of a multilayer metallic slab using multiple-scattering formalism. A thin silver film is attached to a periodic array of heterodimers consisting of two vertically spaced silver nanoparticles of different radii. Depending on the radius of nanoparticles, heterodimer array presents a simple nanoscale geometry which gives rise to remarkable plasmonic properties of multipolar resonances. Due to the coherent interference of the localized nanoparticle plasmons (discrete mode) and surface plasmon polaritons of metallic film (continuous mode), the reflection spectrum represents a sharp asymmetric Fano resonance dip, which is strongly sensitive to the refractive index of the surrounding embedded dielectric host. The physical features contribute to a highly efficient plasmonic sensor for refractive index sensing with sensitivity of ～1.5?×?10^?3 RIU/nm.     

Prediction of Metabolic Syndrome by Non-Alcoholic Fatty Liver Disease in Northern Urban Han Chinese Population: A Prospective Cohort Study

Objectives

To explore the relationship between non-alcoholic fatty liver disease (NAFLD) and the metabolic syndrome (MetS), and evaluate the value of NAFLD as a marker for predicting the risk of MetS in a large scale prospective cohort from northern urban Han Chinese population.

Materials and Methods

A total of 17,920 MetS-free at baseline cohort members was included in the current study between 2005 and 2011. The baseline characteristics of the cohort were compared by NAFLD status at baseline, MetS status after follow-up. Cox proportional hazards models were used to estimate the unadjusted or adjusted hazard ratios (HRs) for NAFLD at baseline predicting the risk of MetS.

Results

2,183 (12.18%) new cases of MetS occurred between 2005 and 2011. In unadjusted model, HRs (95% CIs) for NAFLD predicting MetS was 3.65 (3.35, 3.97). After adjusting the confounding factors of age, gender, the metabolic factors, smoke and exercise, the HRs (95% CIs) was 1.70 (1.55, 1.87). Gender difference was observed, adjusted HRs (95% CIs) of NAFLD for predicting MetS were 2.06(1.72, 2.46) and 1.55(1.39, 1.72) in female and male population, respectively. Moreover, 163 participants developed MetS among participants without any MetS component at baseline, and its adjusted HRs was still significant, 1.87 (1.12, 3.13).

Conclusion

The present study indicates that NAFLD is an independent risk factor for predicting the risk of MetS in northern urban Han Chinese population, and the people with NAFLD should initiate weight and dietary control to prevent the occurrence of MetS.     

有机磷农药在水生态系中生物净化机理研究——3.对硫磷及其降解产物对栅藻光合作用的影响和模拟藻菌系统中对硝基酚的降解

对硝基酚对栅藻光合放氧有明显抑制作用,半抑制浓度在16毫克/升左右;对硝基酚钠对栅藻光合放氧和CO2同化的抑制作用十分一致,它们的半抑制浓度分别在54毫克/升和52毫克/升左右。实验室证明对硝基酚在水体中主要是由细菌分解,藻类起供氧作用。一旦藻类的光合放氧受到抑制,细菌对对硝基酚的好气性降解能力也消失。对硫磷和二乙基硫代磷酸钾对栅藻光合放氧无明显抑制作用。       

有机磷农药生产废水氧化塘处理的静态和动态模拟试验

马拉硫磷、对硫磷、乐果、二甲基二硫代磷酸酯和二乙基硫代磷酸酯在藻菌共生系统中是可以被分解的,它们的半分解期分别为2、5、2、42和62天。氧化塘模拟试验结果指出,废水中TOC、COD、和有机磷的去除率分别为65.1%、68.7%和67.8%。根据试验,提出了采用多级串联氧化塘处理葛店化工厂农药废水的参数以及控制鸭儿湖地区污染的方案。       

Ultra-Subwavelength and Low Loss in V-Shaped Hybrid Plasmonic Waveguide

A new kind of hybrid plasmonic waveguide is proposed, and its propagation properties are investigated using the finite-element method. This waveguide consists of a V-shaped silver nanowire embedded in a low-index dielectric cladding above a semiconductor substrate, which can confine light in the subwavelength region with a long propagation length. The field distribution, the mode effective index, the propagation length, and the normalized mode area of the hybrid mode supported by the waveguide are investigated at the wavelength of 1550 nm, which are dependent on the geometric parameters.     

A 0-Memory Model for Single Ion Channel

This paper discusses a 0-memory model for a single ion channel. The renewal rates of the open-class and the close-class are proposed to deseribe kinetic properties of a single ion channel. Further more, a procedure to estimate the parameters in the model is suggested and illustrated with examples in pharmacology.