太子参品种资源特性的研究

目的:探讨不同太子参品种类型的栽培特性,为实施太子参的GAP生产提供了重要的理论与实践依据。方法:采用道地主产区专题调研法和系统选择法,应用系统分离纯化种源,采用随机区组设计或对比设计,连续3年品比试验及专题研究。结果:太子参大叶型、小叶型、野生型品种间的生物学性状及生产力特性具有极显著差异(P<0.01),生态适应性、植株特征、花粉粒、染色体和同功酶均有显著差别。结论:首次确立了太子参的品种资源类型并进行定名,建立了太子参品种资源分型研究的性状和生产力指标体系。     

火电厂自然降尘对几种人体正常菌株生长的影响

目的研究火电厂自然沉降粉尘对3株人体正常菌的生长作用机制。方法分析所选火电厂粉尘的物相、主要化学成分及粒度分布,测定粉尘与各菌株相互作用后,菌落数、培养基pH值、葡萄糖(GLU)、电解质等相对试验对照样的变化,同时进行扫描电镜(SEM)分析,观察粉尘颗粒与各细菌的界面接触情况。结果3株人体正常菌与火电厂粉尘作用后,Ca2 、Mg2 浓度最大与细菌对照组(0.58mmol/L和0.38mmol/L)相比分别增加了0.69mmol/L(P<0.05)和0.16mmol/L(P<0.05),菌落数与细菌对照组(17×1011CFU/L)相比分别增加了1×1011CFU/L和12×1011CFU/L(P<0.05),而GLU的消耗量、pH值以及其他电解质等变化不明显。结论适量浓度的所选火电厂粉尘对人体正常菌株的生长影响不明显,但火电厂粉尘对人体体表正常菌(表皮葡萄球菌)的生长影响更为显著,更易造成其平衡失调。     

Carcinogenic activity of cigarette smoke gas phase and its modulation by beta-carotene and N-acetylcysteine.

Male strain A/J mice were exposed for six hours a day, five days a week for six months to either full tobacco smoke or to tobacco smoke drawn through a HEPA filter that removed more than 99% of particulate matter. After another four months in air, the animals were sacrificed and lung tumors were counted for calculation of multiplicities and incidences. Analysis of the chamber atmospheres showed that in the filtered smoke the concentrations of polycyclic aromatic hydrocarbons and tobacco smoke specific nitrosamines were reduced to from below 18% to even nondetectable levels of the original values measured in the unfiltered smoke. Aldehydes and other volatile organic compounds such as 1,3-butadiene, benzene, or acrolein were reduced to about 50 to 90% of the concentrations found in unfiltered smoke. Some potentially carcinogenic metals reached levels in filtered smoke ranging from 77% to less than 1% found in full smoke. The mice exposed to the filtered smoke atmosphere had practically identical lung tumor multiplicities and incidence as had the animals exposed to full smoke, significantly higher than in air exposed controls. Diets containing 0.5% beta-carotene or 0.4% N-acetylcysteine afforded some chemoprevention. It was tentatively concluded that 1,3-butadiene might be an important contributor to lung tumorigenesis in this mouse model of tobacco smoke carcinogenesis.     

Immunotoxic effects of short-term atrazine exposure in young male C57BL/6 mice.

The herbicide atrazine (ATR) is a very widely used pesticide; yet the immunotoxicological potential of ATR has not been studied extensively. Our objective was to examine the effect of ATR on selected immune parameters in juvenile mice. ATR (up to 250 mg/kg) was administered by oral gavage for 14 days to one-month-old male C57BL/6 mice. One day, one week, and seven weeks after the last ATR dose, mice were sacrificed, and blood, spleens, and thymuses were collected and processed for cell counting and flow cytometry. Thymus and spleen weights were decreased by ATR, with the thymus being more sensitive than the spleen; this effect was still present at seven days, but not at seven weeks after the last ATR dose. Similarly, organ cellularity was persistently decreased in the thymus and in the spleen, with the splenic, but not thymic cellularity still being depressed at seven weeks post ATR. Peripheral blood leukocyte counts were not affected by ATR. There were also alterations in the cell phenotypes in that ATR exposure decreased all phenotypes in the thymus, with the number of CD4(+)/CD8(+) being affected the least. At the higher doses, the decreases in the thymic T-cell populations were still present one week after the last ATR dose. In the spleen, the CD8(+) were increased and MHC-II(+) and CD19(+) cells were decreased one day after the last ATR dose. Also, ATR treatment decreased the number of splenic na?ve T helper and T cytotoxic cells, whereas it increased the percentage of highly activated cytotoxic/memory T cells. Interestingly, the proportion of mature splenic dendritic cells (DC; CD11c(high)), was also decreased and it persisted for at least one week, suggesting that ATR inhibited DC maturation. In the circulation, ATR exposure decreased CD4(+) lymphocytes at one day, whereas at seven days after the last ATR dose, in addition to the decrease in CD4(+) lymphocytes, the MHC-II(+) cells were also decreased at the 250 mg/kg dose. Thus, ATR exposure appears to be detrimental to the immune system of juvenile mice by decreasing cellularity and affecting lymphocyte distribution, with certain effects persisting long after exposure has been terminated.     

绿舒筋总生物碱对人肝癌细胞抑制作用

目的:研究绿舒筋对体外培养肝癌细胞株的抑制效应.方法:采用乳酸脱氢酶释放法测定绿舒筋、5-Fu、环磷酰胺对体外培养肝癌细胞株的毒性作用.结果:绿舒筋具有抑制肿瘤生长作用,并随药物浓度增加其效应增强,其效应类似于5-Fu和环磷酰胺.结论:绿舒筋具有较好的抗肿瘤细胞生长作用,可望成为临床抗癌药物.     

竹黄无性株的液态发酵工艺研究

从野生竹黄子实体分离获得能产生竹红菌素的无性株,经液态发酵培养及摇瓶正交试验获得最佳培养基配方和培养条件:蔗糖20 g/L,酵母膏8 g/L,玉米浆2 g/L,pH 6.0,摇瓶装量50/250 ml(V/V),接种量10%(V/V),培养温度28℃,摇床转速130 r/min,培养周期96 h,每升发酵液可获得色价为52的竹红菌素8 g.本试验结果可为工业化生产竹红菌素提供参考.     

推拿治疗慢性腰肌劳损临床随机对照研究

目的评价推拿治疗慢性腰肌劳损的临床疗效。方法将110例慢性腰肌劳损患者按照1∶1比例随机分为治疗组和对照组,每组55例。治疗组接受为期4周的推拿治疗,对照组接受为期4周的规范健康教育。分别于治疗前、治疗后、治疗结束后1个月评价疼痛VAS评分和中文版改良ODI指数。结果共有99例患者完成整个研究。与本组治疗前比较,治疗后两组VAS评分、ODI在不同访视点均显著降低(P0.001);治疗后及治疗结束后1个月时,治疗组VAS评分、ODI下降幅度均大于对照组(P0.001)。结论推拿能够缓解慢性腰肌劳损患者的腰痛症状,改善腰部功能活动,且疗效优于健康教育。     

MDR1基因稳定表达的人肝癌多药耐药细胞株的建立

目的 建立多药耐药基因(MDR1)稳定表达的人肝癌Bel-7402耐药细胞株，为应用RNA干扰技术逆转肿瘤多药耐药基因的表达提供实验模型。方法 应用阿霉素(ADM)长期培养筛选建立Bel-7402耐药细胞株，应用MTT法、流式细胞仪(FCM)及逆转录聚合酶链反应(RT—PCR)对该细胞株相关特性(耐药范围、致死剂量、p-糖蛋白功能及其表达阳性率、MDR1基因检测)进行比较研究。结果 经MTT法检测，耐药细胞株耐药性明显增高，FCM检查发现从敏感细胞到耐药细胞，其阿霉素潴留功能由77．7％降至25．1％，P-糖蛋白(P—gp)阳性率由1．4％升高至54．0％，RT-PCR检查显示该细胞中MDR1 mRNA呈高表达。结论 成功建立了稳定表达MDR1基因的人肝癌Bel-7402耐药细胞株，该细胞中P—gp呈高表达，稳定性好。     

Ge/Al and Ge/Si3N4/Al Core/Shell Quantum Dot Lattices in Alumina: Boosting the Spectral Response by Tensile Strain

We investigated the production conditions and optoelectrical properties of thin film material consisting of regularly ordered core/shell Ge/Al and Ge/Si₃N₄/Al quantum dots (QDs) in an alumina matrix. The materials were produced by self–assembled growth achieved by means of multilayer magnetron sputtering deposition. We demonstrated the successful fabrication of well-ordered 3D lattices of Ge/Al and Ge/Si₃N₄/Al core/shell quantum dots with a body-centred tetragonal arrangement within the Al₂O₃ matrix. The addition of shells to the Ge core enables a strong tuning of the optical and electrical properties of the material. An Al shell induces a bandgap shift toward smaller energies, and, in addition, it prevents Ge oxidation. The addition of a thin Si₃N₄ shell induces huge changes in the material spectral response, i.e., in the number of extracted excitons produced by a single photon. It increases both the absolute value and the width of the spectral response. For the best sample, we achieved an enhancement of over 250% of the produced number of excitons in the measured energy range. The observed changes are, as it seems, the consequence of the large tensile strain in Ge QDs which is induced by the Si₃N₄ shell addition and which is measured to be about 3% for the most strained QDs. The tensile strain causes activation of the direct bandgap of germanium, which has a very strong effect on the spectral response of the material.     

Mechanical and Metallurgical Characterization of Nickel-Titanium Wire Types for Rotary Endodontic Instrument Manufacture

This study aimed to evaluate and compare the effects of ambient temperature and post-manufacture heat-treatment on the mechanical behavior of nickel-titanium (NiTi) wires. Four types of commercial NiTi variants (Stock NiTi, heat treated “Blue”, “Gold”, “Superflex”, all Dentsply Maillefer, Ballaigues, Switzerland) were stressed in a tensile testing machine in a temperature-controlled water bath at three different temperatures. Stress and strain values were extrapolated from the raw data, and 2-way ANOVA and Tukey’s test for multiple comparisons were performed to compare the differences of the mechanical constants. Differential scanning calorimetry (DSC) tests established the martensitic transformation starting (M_s), finishing (M_f) and austenitic (reverse-martensitic) starting (A_s) and finishing (A_f) points. Austenitic modulus of elasticity and transformation stress values increased with temperature for all NiTi groups. The martensitic modulus of elasticity, maximum transformation strain and ultimate tensile stress were not significantly affected by temperature changes. Stock NiTi and Gold wire samples presented with clearly delineated austenitic and martensitic transformations in the DSC experiments. Differences in manufacturing/heat treatment conditions and ambient temperature affect the mechanical behavior of nickel-titanium and may have clinical implications. Further improvements to the experimental setup could be considered to provide more accurate measurements of strain.