Plant-derived compounds inactivate antibiotic-resistant Campylobacter jejuni strains

Sixty-three Campylobacter jejuni isolates were screened for their resistance to the antibiotics ampicillin, cefaclor, ciprofloxacin, erythromycin, gentamycin, tetracycline, and trimethoprim-sulfamethoxazole. Based on this screen, the resistant strains D28a and H2a and the nonresistant strain A24a were selected for evaluation of their resistance and susceptibility to inactivation by cinnamaldehyde and carvacrol, the main constituents of plant-derived cinnamon and oregano oils, respectively. Different concentrations (0.05, 0.1, and 0.2% [vol/vol] in sterile phosphate-buffered saline) of cinnamaldehyde and carvacrol were added to C. jejuni cultures with initial populations of 10(4) CFU/ml. The samples were then mixed thoroughly and incubated at 37 degrees C. Viable bacterial populations were enumerated at incubation periods of 0, 30, 60, and 120 min. The results indicate that the extent of inhibition of microbial survival was related to both the nature and concentration of antimicrobials and the incubation time. Both cinnamaldehyde and carvacrol exhibited rapid antimicrobial activity against both antibiotic-resistant and non-resistant C. jejuni strains, at concentrations of approximately 0.1% and higher. The antimicrobial efficacy of cinnamaldehyde was greater than that of carvacrol. The possible significance of the results for microbiological food safety is discussed.     

VSP资料在转换波层位标定中的应用

利用VSP资料可以较好地解决地面多分量转换波的层位标定问题,其基本原理和方法是：首先利用水平分量的下行横波扶得横波初至,利用水平分量的上行转换波获得上行转换波的双程时间剖而,利用垂直分量剖面获得纵波初至;然后由纵波初罕和横波仞至得到转换波的时深关系;再通过转换波的时-深关系和双程时间剖面对过井转换波剖面进行层位标定。应用该方法对广安地区05GA3C04线过GA101井的地面三分量转换波偏移剖面进行了层位标定,并将标定结果用于纵波与转换波的联合解释和岩性剖面解释．得到的结果与工区内的钻井结果吻合。     

盐湖盆地复杂岩性区储层预测方法研究——以江汉盆地潜江凹陷为例

通过对江汉盆地潜江凹陷王-广-浩地区古近系潜江组潜4段0油组半咸化期砂岩储层的预测,形成了一套剖析盐湖盆地复杂岩性区储层的预测方法——"四定法"储层预测技术,即:地质地震复合相定相带、岩石物理建模定标志、多属性地质综合分析定边界、确定性反演定厚度。近3年来,采用"四定法"在潜江凹陷进行边研究、边实践、边总结,发现了多个高产滩坝岩性油藏,取得了较好的勘探效果。该方法的推广应用,可有效提高复杂岩性区储层预测的准确性。     

试井早期资料解释方法

针对低渗油气藏压力恢复缓慢、受井筒存储影响严重的早期试井资料,开展续流量反褶积的解释方法研究。利用Laplace数值变换算法及Laplace空间的反褶积方法,开发含井筒存储效应的直接反褶积数学方法,提出综合常规解释方法的反褶积途径。通过常规双对数分析,确定井筒存储系数进行反褶积,展现半对数径向流特征,减少早期资料解释多解性。     

库车坳陷东部古近系—白垩系储层控制因素及有利勘探区

库车坳陷东部山前复杂构造区储层受沉积相、成岩作用、埋深及构造应力等多种因素控制,有效储层分布预测难度大。通过综合研究,首次建立起库车东部白垩系对比关系,明确白垩系巴什基奇克组在库车东部广泛分布,受沉积微相及物源分布影响,储层物性具有从东到西、从北到南变好的趋势。刚性颗粒含量较高的储层预测有效埋深可以大于7000m。古构造应力对储层的构造压实作用从造山带向盆地减弱。结合多种控制因素预测了有利储层勘探区。     

改性聚乙烯醇防塌剂研究

针对聚乙烯醇做为防塌剂存在问题,对其进行了改性处理,研制出新型的改性聚乙烯醇防塌剂。实验结果表明,改性聚乙烯醇防塌剂具有很强的抑制性作用,能显著降低钻井液摩擦系数,与其它处理剂配伍性好,对钻井液流变性和滤失性具有一定的改善作用,满足环境要求,是一种环保型多功能防塌剂。     

哈尔金混合气藏成因及气体的垂向分布规律

松辽盆地长岭断陷哈尔金气藏（营城组）是烃类（CH₄）与CO₂混合气藏。对哈尔金混合气藏成因、气源特征及成藏期次研究表明,该混合气藏是烃类先于CO₂注入,气藏定型于新近纪,属晚期成藏。根据天然气在气藏中浮力与毛细管力平衡的物理模型,推演出烃类气藏含气饱和度分布的数学模型,该模型反映了储层中原始含气饱和度分布的基本原理。混合气藏中各种气体垂向分布符合重力分异原理,在均匀介质储层条件下,从气藏的底部向顶部,密度较大的CO₂饱和度逐渐降低,而密度相对较小的CH₄饱和度逐渐增加。在构造混合气藏的多孔介质储层中,密度大的CO₂气占据较大的孔隙部分,密度相对较小的CH₄气占据中等孔隙部分,而束缚水占据较小的孔隙部分。哈尔金混合气藏顶部CO₂含量高于底部是由于储层孔隙结构的变化所致。     

白音查干油田污水回注配伍性试验与评价

白音查干油田地层水具有高SO4^2-、Cl^-、高矿化度的特征,水型大都为Na2SO4型。试验表明：油井产出水混合、混合水注入油井后均会产生结垢现象,配伍性较差。但经净化、絮凝、过滤及阻垢处理后,能够达到混合回注对水质的要求。     

烤烟新品种南江3号的选育及其特征特性

南江3号是从红花大金元品种中获得的自然变异株,经系统选择培育而成.该品种适应性强,易烘烤,中抗赤星病、黑胫病和青枯病,气候斑点病轻.烟叶外观品质好,烟碱含量适中,化学成分协调,烟叶吸食品质与贵州省主栽品种K326相当,符合中式卷烟发展对原料的需求.主要经济性状与K326比较,产量提高15.71%,产值增加33.93%,具有生产应用价值.     

Rigorous mathematical modeling techniques for optimal delivery of macromolecules to the brain

Several treatment modalities for neurodegenerative diseases or tumors of the central nervous system involve invasive delivery of large molecular weight drugs to the brain. Despite the ample record of experimental studies, accurate drug targeting for the human brain remains a challenge. This paper proposes a systematic design method of administering drugs to specific locations in the human brain based on first principles transport in porous media. The proposed mathematical framework predicts achievable treatment volumes in target regions as a function of brain anatomy and infusion catheter position. A systematic procedure to determine the optimal infusion and catheter design parameters that maximize the penetration depth and volumes of distribution will be discussed. The computer simulations are validated with agarose gel phantom experiments and rat data. The rigorous computational approach will allow physicians and scientists to better plan the administration of therapeutic drugs to the central nervous system.