Long-chain alkenones in sulfate lakes and its paleoclimatic implications

Long-chain alkenones are ubiquitous in marinesediments. The relationship between alkenone unsatura-tion and temperature has been proved by field studies andcultures of E. huxleyi[1] and G. oceanica[2]. As an idealproxy for sea surface paleotemperature estimation, theU37 index is widely applied to reconstructing paleotem- K 'perature in most oceanographic settings[3—10]. The suc-cessful progresses in the ocean invoked the researchers’attention to the study of LCAs in the liminic system.Cr…     

固体氧化物燃料电池

论述了固体氧化物燃料电池（ＳＯＦＣ）,分析了固体氧化物燃料电池在电介质和电极材料面的性能和特点,介绍了固体氧化物燃料电池目前的应用和发展前景。     

中学化学校内考试改革的尝试与思考

恰当的校内考试,可有效地培养学生的竞争意识,提高教学水平。但学生基础不同,兴趣各异,在全面实施素质教育的过程中,校内考试要面向全体学生,注意个性差异。实行分类,分项,分期考试,实施综合评价,才能使学生充分感受“成功”,增强信心,促其全面发展。     

阻带可控陷波超宽带天线的设计与时域分析

针对传统陷波结构只能在单个频点上实现陷波的局限性,文中通过使用开路槽线方法,提出和实现了一种阻带带宽可控且矩形度良好的微带馈电陷波超宽带天线．通过在超宽带天线U形辐射贴片上添加两个L形开路槽线和在馈线端添加一个U形槽线来实现陷波特性,通过调节两个L形开路槽线与U形辐射贴片的耦合间距来控制陷波阻带的带宽．除了阻带5.1～5.8GHz 频段之外,该天线在3.1～10.6GHz 超宽带频段内获得了很好的宽带阻抗匹配．文中还对该陷波超宽带天线进行了时域分析,计算了天线相关系数和脉冲宽度拉伸比．测量与仿真结果吻合良好,说明该陷波天线能有效地应用于超宽带系统．     

A STUDY OF THE SPECIMEN SIZE OF STRIP TENSILE TEST FOR NEEDLE-PUNCHED NON-WOVEN GEOTEXTILES

In this paper,the failure features of strip tensile specimen were observed and analysed for need-le-punched non-woven geotextiles.A mechanical model which expresses the relation between thetensile modulus,the strip specimen size,contraction factor and the tensile strength of non-wovenfabric was derived.The theoretical prediction showed that the main factor influencing tensilestrength of non-woven geotextile specimens with different size is the contraction factor of specimenor the specimen aspect ratio(width/length).The larger the aspect ratio,the higher the tensilestrength test value of geotextiles,but the experiments showed that the specimen tensile strength isnot increased with increasing the width of specimen.The reason was discussed and it seemed thatthe deviation could be served as an indication of the degree of imperfectness of the non-wovenstructure.     

参附注射液通过调节核内HMGB1和NF-κB结合发挥抗炎活性的机制

探讨参附注射液(Shenfu injection,SFI)对脂多糖(lipopolysaccharides,LPS)诱导的RAW264.7细胞的抑炎作用及其潜在机制.采用LPS诱导野生型RAW264.7细胞制作炎症细胞模型,经参附注射液不同剂量进行干预,RT-qPCR、WB和ELISA检测细胞内促炎因子,包括诱导型一氧化氮合酶(induced nitric oxide synthase,iNOS)、白介素-1 β(interleukin-1 β,IL-1 β)和肿瘤坏死因子α(tumor necrosis factor α,TNF-α)的转录、翻译和分泌水平,评价参附注射液的抗炎作用;构建高迁移率组蛋白B1(high mobility group protein B1,HMGB1)过表达 RAW264.7 细胞(HMGB1+-RAW264.7)和 HMGB1 点突变 RAW264.7 细胞(HMGB1m-RAW264.7),通过免疫荧光检测野生型、HMGB1+和HMGB1m-RAW264.7细胞中HMGB1的核移位情况,采用哺乳动物双杂交法和免疫共沉淀法检测HMGB1、P65和P50的结合率,以探讨核内HMGB1在炎症反应中的作用及SFI抗炎的潜在分子机制.结果表明:SFI可抑制LPS诱导的RAW264.7细胞中iNOS、IL-1β和TNF-α的转录、表达和分泌(P＜0.01).SFI能抑制HMGB1向核外迁移,使其高表达于核内.核内高表达HMGB1可使RAW264.7细胞对LPS的耐受度增加.在1 µg/mL浓度LPS诱导下,HMGB1+-RAW264.7细胞中TNFα和IL-1β的转录和表达水平均升高,且SFI能逆转这一现象.HMGB1m-RAW264.7细胞中TNFα和IL-1β与对照组无差异.SFI可增加核内HMGB1与P65、HMGB1与P50的结合率(P＜0.01),减少P50与P65的结合率.试验结果表明:SFI可抑制LPS诱导的RAW264.7细胞炎症反应;其作用途径可能是通过抑制HMGB1出核,竞争性结合P65和P50合,减少P65-P50二聚体的形成,进而抑制核因子κB(nuclear factor kappa-B,NF-κB)通路的激活.     

氮三乙酸根合铬(Ⅲ)与3-苯基偶氮-5-磺基水杨酸的反应动力学

pH为4．4～7．6,温度为40℃,离子强度为0．1mol·dm-3（NaClO4）条件下,研究了［Cr（NTA）（H2O）（H2O）／（OH）－］与染料3－苯基偶氮－5－磺基水杨酸（PASSA）的混配络合物的生成反应动力学．拟1级速率常数为kobs,反应符合Eigen机理．因速率常数（k1,k2）大于水交换速率（kex）,故此反应可归属于交换缔合机理。