硅烷偶联剂的研究与应用

硅烷偶联剂是应用最广的一类偶联剂。本文阐述了其结构特征、偶联机理与使用技术,着重综述了硅烷偶联剂的应用范围与具体应用效果,最后展望了硅烷偶联剂的发展方向。     

河豚毒素的起源及其研究进展

河豚毒素(tetrodotoxin,TTX)是一种毒性很强、相对分子质量小的非蛋白毒素,最初从豚科鱼中发现,故被命名为河豚毒素。1985年有人提出了河豚鱼TTX的体外起源因素,认为所有能产生TTX的生物都与其体内能分泌TTX的微生物有着密切联系,但有部分研究人员证实东方在孵化期间能自行产生TTX。TTX为典型的Na 通道阻断剂,中毒者往往肢体麻木、瘫痪、甚至死亡;但另一方面,TTX具有镇痛、镇静、降压等功效,在临床上的应用十分广泛。本文简要介绍TTX的起源、毒性作用机制、毒性控制、临床及药理学上的应用,及其存在的问题和应用前景。     

低分子量肝素钠的制备与临床应用

低分子肝素有抗凝血、抗血栓、调血脂、抗肿瘤等作用,与普通肝素相比具有皮下注射吸收好、半衰期长、生物利用率高,与血浆、血小板亲和力小、出血副作用少等优点.对低分子肝素的制备、质量检测和临床应用的研究进展进行了综述.     

Evaluating the physiological effect of strobilurin-based fungicide (Opera 183 g/L SE) against Sclerotium rolfsii and Aspergillus niger pathogens of Arachis hypogaea L.

Abstract

The present study was designed to investigate the effect of fungicide Opera 183?g/L SE on groundnut crop (either as seed or foliar treatment) to control damages and losses incurred especially by the soil borne pathogens Sclerotium rolfsii and Aspergillus niger. The results revealed that 0.15% Opera-treated seeds showed early germination, high percentage of germination, less mortality rate in S. rolfsii and A. niger-infested soil. Enhanced activities of defence-related enzymes, protein, carbohydrate and chlorophyll content up to 2–4 d were observed in Opera-treated plants as compared with untreated plants. Moreover, the application of Opera had a positive effect on yield up to 22%, green fodder at the time of harvest and no disease incidence. From the present study, it is recommended that application of Opera at 750?ml/hectare in the form of foliar treatment to groundnut plants could help in inducing resistance towards opportunistic pathogens and also could enhance the yield.     

Analytical methods for detecting pesticide switches with evolution of pesticide resistance

After a pest develops resistance to a pesticide, switching between different unrelated pesticides is a common management option, but this raises the following questions: (1) What is the optimal frequency of pesticide use? (2) How do the frequencies of pesticide applications affect the evolution of pesticide resistance? (3) How can the time when the pest population reaches the economic injury level (EIL) be estimated and (4) how can the most efficient frequency of pesticide applications be determined? To address these questions, we have developed a novel pest population growth model incorporating the evolution of pesticide resistance and pulse spraying of pesticides. Moreover, three pesticide switching methods, threshold condition-guided, density-guided and EIL-guided, are modelled, to determine the best choice under different conditions with the overall aim of eradicating the pest or maintaining its population density below the EIL. Furthermore, the pest control outcomes based on those three pesticide switching methods are discussed. Our results suggest that either the density-guided or EIL-guided method is the optimal pesticide switching strategy, depending on the frequency (or period) of pesticide applications.     

Chronopharmacokinetics of Imipramine and Desipramine in Rat Forebrain and Plasma After Single and Chronic Treatment with Imipramine

Daily variations in the pharmacokinetics of imipramine (IMI) could contribute to circadian phase-dependent effects of the drug. Therefore, the chronopharmacokinetics of IMI and its metabolite, desipramine (DMI), were studied after single and chronic application. Male rats were synchronized to a 12:12 hour lightdark (L:D) regimen with lights on from 07:00 to 19:00 (dark, 19:00-07:00). In single-dose experiments rats were injected with IMI (10 mg/kg) i.p. or i.v. at 07:30 or 19:30 and groups of rats were killed 0-22 hours thereafter. After chronic application of IMI in drinking water (≈ 15 mg/kg/d) groups of rats were killed during the 14th day of treatment at 02:00, 08:00, 14:00, and 20:00, respectively. Brain and plasma concentrations of IMI and DMI were determined by reversed-phase high-performance liquid chromatography with ultraviolet detection. After single i.p. application of IMI, maximal brain concentrations (C_max) of IMI and DMI were nearly twofold higher in darkness (IMI, 4.8 μg/g; DMI, 1.8 μg/g) than in light (IMI, 2.85 Mg/g; DMI, 0.85 Mg/g). Also, the area under the curve (AUC) (0-22 hours) was about 1.6-fold greater in darkness than in light for IMI and DMI; half-lives were not circadian phase dependent. After i.v. injection of IMI, the AUC in brain was also about 30% greater in darkness than in light. After chronic application of IMI in drinking water, brain concentrations of IMI and DMI varied more than threefold within 24 hours. The data demonstrate that the pharmacokinetics of IMI and DMI are circadian phase dependent. It is assumed that circadian variations in drug distribution are more likely to contribute to the drug's chronopharmacokinetics than variations in the drug's metabolism. The 24-hour variations in the drug's concentrations after chronic IMI application in drinking water can be explained by the drinking behavior of the rats, which by itself is altered by IMI.     

根际CO2浓度升高对网纹甜瓜光合特性及产量和品质的影响

采用雾培植株根际通CO₂处理方式,研究了开花结果期根际CO₂浓度升高对网纹甜瓜光合作用及产量和品质的影响.结果表明：在网纹甜瓜果实发育期间,与350 μL·L^-1（对照）处理相比,根际2500和5000 μL CO₂·L^-1处理的叶片光合色素含量、净光合速率（P_n）、气孔导度（g_s）、胞间CO₂浓度（C_i）及PSⅡ最大光化学效率（F_v/F_m）均不同程度降低,而气孔限制值（L_s）显著提高,且5000 μL CO₂·L^-1处理的变化幅度高于2500 μL CO₂·L^-1处理;单株产量、果实中维生素C和可溶性糖含量显著降低,有机酸含量显著提高.可见,网纹甜瓜果实发育期间根际CO₂浓度超过2500 μL·L^-1时,其光合作用及果实发育会受到显著抑制,从而导致产量和品质降低.
     

Comparative effects of insecticides with different mechanisms of action on Chrysoperla externa （Neuroptera＂ Chrysopidae）＂ Lethal,sublethal and dose-response effects

The comprehensive knowledge that the delayed systemic and reproduction side effects can be even more deleterious than acute toxicity, has caused a shift in focus toward sublethal effects assessment on physiology and behavior of beneficial insects. In this study, we assessed the risks posed by some insecticides with different mode of action through lethal and delayed systemic sublethal effects on the pupation, adult emergence, and repro- duction of the chrysopid Chrysoperla externa （Hagen, 1861; Neuroptera： Chrysopidae）, an important predator in pest biological control. The maximum field recommended dose （MFRD） and twice （2xMFRD） for chlorantraniliprole, tebufenozide, and pyriproxyfen were harmless to C. externa. In contrast, all the tested chitin synthesis inhibitors （CSIs） were highly detrimental to the predator, despite of their lack of acute lethal toxicity. There- fore, the safety assumed by using IGRs toward beneficial insects is not valid for chrysopids. Dose-response data showed that although all CSIs have a similar mechanism of action, the relative extent of toxicity may differ （novaluron 〉 lufenuron 〉 teflubenzuron）. For CSIs, the delayed systemic effects became obvious at adult emergence, where the predicted no observable effect dose （NOED） was 1/2 048 of the MFRD for novaluron （0.085 ng/insect）, and 1/256 of the MFRD for both lufenuron （0.25 ng/insect） and teflubenzuron （0.6 ng/insect）. Finally, this work emphasized the significance of performing toxicity risk assessments with an adequate posttreatment period to avoid underestimating the toxicities of insecticides, as the acute lethal toxicity assays may not provide accurate information regarding the long-range effects of hazardous compounds.     

专项整治对综合医院抗菌药物使用强度的影响

??????? 目的 探讨抗菌药物临床应用专项整治活动对综合医院住院患者抗菌药物使用强度的影响。方法 以限定日剂量（DDD）为单位,对某综合性医院在实施专项整治前、后住院患者抗菌药物使用强度（AUD）进行统计、分析。结果 专项整治活动降低了住院患者累计AUD值,大环内酯类等药物AUD明显下降,第二代、第三代和第四代头孢菌素和不同管理级别抗菌药物AUD均下降。但还存在用药集中、注射用头孢哌酮钠舒巴坦钠AUD下降不明显等问题。结论 专项整治有效降低了综合医院住院患者AUD,但与卫生行政部门标准仍存在差距,应进一步加强管理。