含Euxyl K220的复合防腐剂在化妆品中的防腐效果研究

为寻求新型复合防腐剂,研究了含有Euxyl K220的不同种类复合防腐剂在化妆品基质中的作用效果并进行评价。选择4种防腐剂按照不同方法复配,利用微生物挑战性试验验证复配后的复合防腐剂在化妆品基质中的防腐效果。结果发现,对羟基苯甲酸甲酯质量分数低于0.1%时,含Euxyl K220的复合防腐剂抑制细菌效果稍好,抑制霉菌效果较差,不能通过挑战性试验,而当存在Euxyl PE9010时,抑制细菌、霉菌效果均较好,能通过挑战性试验;对羟基苯甲酸甲酯质量分数在0.1%~0.2%时,含Euxyl K220的复合防腐剂抑菌效果最好,Euxyl K220在相对较低的质量分数(0.08%)下即能通过挑战性试验。研究制备的对羟基苯甲酸甲酯(质量分数0.2%)和Euxyl K220(质量分数0.08%)复合防腐剂,以及对羟基苯甲酸甲酯(质量分数0.05%)、Euxyl K220(质量分数0.1%)和Euxyl PE9010(质量分数0.2%)复合防腐剂应用于受试样品中均通过了挑战性试验且用量较低,该两种新型复合防腐剂的应用可行性较高。     

全球一体化竞争环境下传统氯碱企业在危机中的战略突围

目前,中国氯碱产业正处于产能过剩、竞争激烈的微利时代,传统的氯碱企业其技术优势已无法与拥有煤炭、电石、原盐、热电等资源优势的新兴企业抗衡。而随着中东和美国凭借廉价的石油和天然气资源逐渐将氯碱产业布局全球,一体化国际市场和全球自由竞争给中国的传统氯碱企业提供了一个“凤凰涅槃”的机会,把空前的困难和挑战变为推进改革的力量,传统氯碱企业仍然能够迎来春天。     

边际油田开发技术现状、挑战与对策

中国陆上边际油田主要包括低渗透、稠油和复杂断块等特殊类型难采油田。中国在难采边际储量的开发方面进行了大量的研究和现场试验，积累了一些成功的经验，初步建立难采边际油田经济有效的开发技术。近年新发现的油田绝大部分属于特低渗、低产、低丰度、高黏度等边际油田，开采难度增大。因此，迫切需要加强地质和工程基础研究，加强技术创新，积极探索针对不同油藏的开发模式和策略，积累经验，转变观念，创立科学、实用和有效的技术措施。边际油田开发最核心的问题是经济问题，因此必须因地制宜，降低成本，简化钻采工艺、地面工艺和流程，借鉴其他类型油藏的开发技术，提高边际油田经济效益。参34     

Protective Immunity against Listeria monocytogenes in Rats,Provided by HCl- and NaOH-Induced Listeria monocytogenes Bacterial Ghosts (LMGs) as Vaccine Candidates

Listeria monocytogenes (Lm) bacterial ghosts (LMGs) were produced by the minimum inhibitory concentration (MIC) of HCl, H₂SO₄, and NaOH. Acid and alkali effects on the LMGs were compared by in vitro and in vivo analyses. Scanning electron microscope showed that all chemicals form lysis pores on the Lm cell envelopes. Real-time qPCR revealed a complete absence of genomic DNA in HCl- and H₂SO₄-induced LMGs but not in NaOH-induced LMGs. HCl-, H₂SO₄- and NaOH-induced LMGs showed weaker or missing protein bands on SDS-PAGE gel when compared to wild-type Lm. Murine macrophages exposed to the HCl-induced LMGs showed higher cell viability than those exposed to NaOH-induced LMGs or wild-type Lm. The maximum level of cytokine expression (TNF-α, iNOS, IFN-γ, and IL-10 mRNA) was observed in the macrophages exposed to NaOH-induced LMGs, while that of IL-1β mRNA was observed in the macrophages exposed to HCl-induced LMGs. To investigate LMGs as a vaccine candidate, mice were divided into PBS buffer-injected, HCl- and NaOH-induced LMGs immunized groups. Mice vaccinated with HCl- and NOH-induced LMGs, respectively, significantly increased in specific IgG antibodies, bactericidal activities of serum, and CD4⁺ and CD8⁺ T-cell population. Antigenic Lm proteins reacted with antisera against HCl- and NOH-induced LMGs, respectively. Bacterial loads in HCl- and NaOH-induced LMGs immunized mice were significantly lower than PBS-injected mice after virulent Lm challenges. It suggested that vaccination with LMGs induces both humoral and cell-mediated immune responses and protects against virulent challenges.     

PCB行业充满着挑战的年代

文章概述了在2009中国PCB工业面临的四大挑战。     

头门港发展策略探讨

以港口开发尚处于启动阶段的临海市头门港为例,分析了港口开发的有利条件和面临的挑战,进而提出了有针对性的、可供当地政府部门参考的港口发展策略和建议,以期高效推动港口的开发和建设。     

钢铁大学网站历年虚拟炼钢挑战赛总结及其资源应用

介绍了世界钢铁协会名下钢铁大学网站虚拟炼钢挑战赛的历年赛事情况，列举了一些知名公司对该资源的利用，建议中国钢铁公司能利用并参与到这个国际性学习活动中来。     

Work stressors, role-based performance, and the moderating influence of organizational support.

As a test of the 2-dimensional model of work stressors, the present study proposed differential relationships between challenge stressors and hindrance stressors and role-based performance, which were expected to be moderated by organizational support. In a sample of 215 employees across 61 offices of a state agency, the authors obtained a positive relationship between challenge stressors and role-based performance and a negative relationship between hindrance stressors and role-based performance. In addition, organizational support moderated the relationship between challenge stressors and role-based performance but did not moderate the relationship between hindrance stressors and role-based performance. This suggests that organizations would benefit from increasing challenges in the workplace as long as they are supportive of employees and removing hindrances. Further implications for organizational theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

知识经济时代成人高等教育面临的挑战及对策

成人高等教育作为一种与社会经济发展最紧密的教育，也面临着知识经济带来的机遇与挑战，由此提出了知识经济时代成人高等教育的创新和改革的基本思路．     

经济全球化对我国注册会计师审计的挑战

从四个方面分析经济全球化对我国审计行业的挑战，指出了目前中国会计师事务所存在的问题，这些问题将会影响会计师事务所的生存，本文对解决这些问题提出了一些有益的建议。