986 resultados para 399
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In this work, the photosynthetic performances of Enteromorpha prolifera thalli collected from the surface and bottom of the sea of Qingdao sea area were studied with chlorophyll fluorescence and oxygraph technology. The samples with the highest photosynthetic activity among their kinds, the floating thalli from the sea surface of the south of the Qingdao Olympic Sailing Center and the sedimentary thalli from the mud surface of the bottom Tuandao bay, were chosen as representatives of surface thalli and bottom thalli, respectively. The results showed that the maximal PSII quantum yield of the floating thalli was significantly lower than the normal level although their photosynthetic activities were relatively high; the photosynthetic potential of the thalli form the mud surface was extremely low. Thus, it is indicated that the floating thalli are seriously stressed by their environment and the thalli from the mud surface are already dead or are dying. On the other hand, the results of the laboratory cultivation showed that the sedimentary thalli cannot regain normal photosynthetic activity even under normal illumination conditions. Thus, the thalli from the mud surface cannot become reproductive source of the alga even if they can reach sea surface again. Therefore, a preliminary conclusion can be reached that, up to mid-July 2008, the environmental conditions of the Qingdao sea area are not suitable for the growth of the alga E. prolifera and for this reason the biomass of E. prolifera, in the area, could be declining.
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One-celled female and male gametophytes of three Laminaria japonica strains were isolated, cultured and gametophyte clones were formed. A technique combining strain selection with sporeling raising by the use of these female and male gametophyte clones was studied. Experiments on 9 different crossing combinations was conducted in November of 1997 in Qingdao, P. R. China. The main economic characteristics, frond length and fresh weight, of sporophytes of different crossing combinations were measured. F-1 sporophytes of No. 2 showed a higher fresh weight and longer length, therefore, No. 2 (Wh860 + x Lid) was selected as a good combination. Its parental female and male gametophyte clones are being mass cultured for sporeling production. By this method, the time needed for strain selection was shortened from 5-6 to 2 years. As compared with the routine method of sporeling raising by the collection of zoospores, the time of sporeling raising of this method decrease by 50%, and the production cost is also reduced by 50%. It is believed that this method will be labour and time saving and a more economic way for strain selection and sporeling raising in L. japonica cultivation industry.
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Progress has been made in establishing a genetic transformation model for Laminaria japonica (Phaeophyta, Laminariales). The model includes introduction of foreign genes by biolistic bombardment, use of promoter SV40 to drive gene expression, algal regeneration by parthenogenesis and selection by chloramphenicol or hygromycin.
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Hsp70 proteins are a family of molecular chaperones that are involved in many aspects of protein homeostasis. In this study, an Hsp70 homologue (SoHsp70) was identified from red drum Sciaenops ocellatus and analyzed at molecular level. The open reading frame of SoHsp70 is 1920 bp and intronless, with a 5'-untranslated region (UTR) of 399 bp and a 3'-UTR of 241 bp. The deduced amino acid sequence of SoHsp70 shares 84-92% overall identities with the Hsp70s of a number of fish species. In silico analysis identified in SoHsp70 three conserved Hsp70 domains involved in nucleotide and substrate binding. The coding sequence of SoHsp70 was subcloned into Escherichia coli, from which recombinant SoHsp70 was purified and, upon ATPase assay, found to exhibit apparent ATPase activity. Expressional analysis showed that constitutive expression of SoHsp70 was detectable in heart, liver, spleen, kidney, brain, blood, and gill. Experimental challenges with poly(I:C) and bacterial pathogens of Gram-positive and Gram-negative nature induced SoHsp70 expression in kidney to different levels. Stress-responsive analysis of SoHsp70 expression in primary cultures of red drum hepatocytes showed that acute heat shock treatment elicited a rapid induction of SoHsp70 expression which appeared after 10 min and 30 min of treatment. Exposure of hepatocytes separately to iron, copper, mercury, and hydrogen peroxide significantly unregulated SoHsp70 expression in time-dependent manners. Vaccination of red drum with a Streptococcus iniae bacterin was also found to induce SoHsp70 expression. Furthermore, recombinant SoHsp70 enhanced the immunoprotective effect of a subunit vaccine. Taken together, these results suggest that SoHsp70 is a stress-inducible protein that is likely to play a role in immunity and in coping with environmental and biological stresses. (C) 2010 Elsevier Ltd. All rights reserved.
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The effective dielectric responses of linear composites with graded cylindrical particles are investigated under an external uniform electric field. As an example, with the Kummer function, we have obtained the analytical solutions of electric potentials of graded composites with a cylindrical inclusion particle of dielectric function profile epsilon(i) = cr(k)e(betar), where r is the inside distance of a point in cylindrical particle from the original point of cylindrical coordinates. In the dilute limit, the effective dielectric response is derived by means of the mean field method. For larger volume fraction, we have estimated the dielectric response of the graded composites with an effective medium approximation. Furthermore, from our results, we have discussed the effective responses of graded composites for power-law and exponential dielectric function profiles, respectively. (C) 2004 Elsevier B.V. All rights reserved.
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目的 了解塞隆骨水提物(SLG—B)对胶原诱导的小鼠关节炎的治疗作用及治疗机制。方法 利用牛Ⅱ型胶原诱导DBA/1小鼠类风湿性关节炎模型即CIA。SLG—B口服给药观察小鼠关节炎指数的变化情况,体外培养关节炎小鼠脾细胞及巨噬细胞,ELISA法测定IL-12、IL-2、IFN-γ TNF-α几种细胞因子。RT-PCR测定SLG-B对关节炎小鼠巨噬细胞IL-1β、IL-6、iNOS mRNA表达的影响。结果 SLG-B能明显的抑制牛Ⅱ型胶原诱导关节炎的发生,能够减轻关节炎的各种症状。SLG-B在加抗原和不加抗原的情况下都能够明显的抑制关节炎小鼠脾细胞的增殖同时发现SLG-B能够抑制IL-2、IFN-1、L-12p40、TNF-α细胞因子的产生。还能够抑制小鼠腹腔巨噬细胞IL-1、IL-6及iNOS mRNA的表达。这可能是SLG—B在小鼠关节炎中表现治疗效果的分子基础。结论 SLG—B对小鼠关节炎有很好的治疗效果,其作用机制主要是通过抑制巨噬细胞及脾细胞产生炎性细胞因子和抑制炎性细胞因子mRNA的表达来达到治疗类风湿性关节炎的作用。
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以吖啶酮-9-乙基对甲苯磺酸酯(AETS)作荧光衍生化试剂,建立了灵敏、简单的游离脂肪酸反相高效液相色谱测定方法。在Eclipse XDB—C8色谱柱上,实现了19种游离脂肪酸(FFA)衍生物的完全基线分离。选取AETS摩尔数为脂肪酸的6倍,以DMF作溶剂,在85℃条件下以K2CO3作催化剂可获得稳定的荧光产物,条件温和、衍生产率高。利用柱后在线串联质谱以APCI大气压化学电离源正离子模式实现了各组分的质谱定性。对土壤和3种苔藓植物中(树藓、狭叶绢藓、曲尾藓)FFA组分定量结果表明,苔藓植物从土壤中富集了大量的游离脂肪酸。荧光检测的激发和发射波长分别为404nm和440nm。绝大多数脂肪酸的线性相关系数大于0.9996,检出限为12.3~43.7fmol。本方法具有良好的重现性,用于实际样品测定,结果满意。
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建立测定了岩白菜中岩白菜素含量的方法.色谱柱:Waters C18柱(5 μm×3.9 mm×150 mm),流动相:甲醇∶水∶磷酸=20∶80∶0.1,流速为1.0 mL/min,检测波长275 nm,AUFS 0.01,柱温为室温.结果表明,岩白菜素在0.16~0.08 μg有良好线性关系,r=0.999 2,平均回收率为98.14%,RSD为1.12%.本方法是测定岩白菜中岩白菜素含量的快速、简便、准确可靠的定量方法.
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微机电系统、先进传感器、无线通信及现代网络等技术的进步,推动了无线传感器网络的产生和发展。集数据采集、处理、无线传输等功能于一体的无线传感器网络扩展了人们的信息获取能力,将逻辑上的信息世界与真实物理世界融合在一起,将改变人类与物理世界的交互方式。 无线传感器网络具有许多挑战性的研究课题,其中部署与定位是无线传感器网络应用的基础问题。部署就是在一定区域内通过适当的策略放置传感器节点以满足某种特定需求,它决定了网络对目标的检测能力。定位在无线传感器网络中包括两层含义:节点定位和目标定位。节点定位是目标定位的前提,会影响目标跟踪的精度。论文面向应用于目标跟踪的无线传感器网络,围绕部署与定位问题展开研究。 论文分别综述了无线传感器网络部署问题、定位问题和目标跟踪问题的研究内容、评价标准、算法分类和研究现状。 从信息覆盖的角度研究满足给定指标的确定性部署问题,提出一种基于检测融合的确定性部署策略。首先采用奈曼-皮尔逊准则融合单元网格内所有传感器节点的检测信息,实现正方形和正三角形两种单元网格的高效覆盖。然后分别给出对应的监测区域网格划分方法,从而确定监测区域需要的传感器节点数量以及放置的具体位置。使用相同数量的传感器节点,基于检测融合的部署策略可以获得更大的覆盖范围,也就是在保证一定感知性能的情况下减少了成本。 针对无线电干涉定位系统的多径效应抑制问题,分别从理论和实验的角度分析多径效应对无线电干涉测距的影响,然后根据多径信号的物理特性,从理论上推导了镜反射的多径误差数学模型,在此基础之上进行无线电干涉定位系统的多径误差分析,讨论了衰减因子、传感器节点天线高度和水平距离等多径参数对多径误差的影响。通过仿真计算和分析可知,衰减因子对多径误差的大小起着决定性作用,而多径误差在定位空间上分布的复杂程度,随着天线高度的增加而增加,同衰减因子无关。 无线电干涉测距技术获取的干涉距离是两个发送节点和两个接收节点间距离的线性组合值。针对以节点间距离作为输入的传统定位算法,无法直接利用上述干涉距离进行定位的问题,提出一种基于改进粒子群优化的定位方法。借鉴遗传算法中变异的思想,在每次迭代时对更新过的粒子位置进行微扰,以维持种群的活性。利用干涉距离的实验数据,分析比较了遗传算法和改进粒子群优化在无线电干涉定位系统节点定位问题中的性能。实验结果表明,两种定位方法都能在有限的进化代数内找到节点坐标的近似值,但是基于改进粒子群优化的定位方法的平均耗费时间,远远小于基于遗传算法的定位方法,具有更高的优化效率。 针对具有簇-树型网络拓扑结构的无线传感器网络,首先给出集中式粒子滤波跟踪算法实现的具体步骤,然后提出两种分布式粒子滤波跟踪算法。综合考虑信息收益和参与协作的资源消耗,两种分布式算法分别采用不同的准则来选择参与跟踪的传感器节点。为了系统地比较跟踪算法的性能,给出跟踪精度、通信开销、能量开销和跟踪反应时间等各项指标的定义,进而构建了综合性能评价体系。通过仿真,量化比较了三种跟踪算法的性能。结果表明,两种分布式算法能够在损失很少跟踪精度的同时,大幅度减少通信开销、能量开销和跟踪反应时间。最后,仿真分析了传感器节点覆盖密度和检测阈值对跟踪算法性能的影响。 总之,论文对无线传感器网络的部署问题、定位问题和目标跟踪问题进行了研究和探讨,旨在对无线传感器网络的应用起到一定的促进作用。
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通过大量岩石、矿石光(薄)片观察鉴定、电子探针分析、首次查明呷村海相火山岩型银多金属状块硫化物矿床有硫砷铜银矿和硫砷铜矿两种硫盐矿物。研究表明,除硫化物外(主要为方铅矿、闪锌矿、黄铁矿,其次为黄铜矿,毒砂,斑铜矿,铜铜银矿,螺硫银矿,磁黄铁矿等),硫盐矿物十分发育,主要有黝铜矿、车轮矿、硫砷铜矿、硫砷铜银矿等。该矿床中的银主要在喷流-沉积成矿阶段富集。
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以壳体大地构造理论为基础,根据滇西三江地区的基本地质事实,对前人的观点进行重新认识和修正,首次提出了该区迄今最全面、最系统的壳体大地构造单元划分方案,将其细分为4个壳段,11个次级单元和3个挤压聚合带,从新的角度揭示了该区区域地质构造的时空演化规律,为区域成矿规律提供了重要的科学依据。
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本文介绍了华南花岗岩型铀矿床地质特征,系统总结了前人对其成矿热液来源、物质来源,铀的迁移沉淀机制、碱交代及花岗岩与成矿的关系等方面的研究成果。指出铀源体中的晶质铀矿及富铀矿物在深部相对还原的环境中被氧化而进入成矿热液中起主要作用的可能是大量幔源F和放射性衰变诱发产生的氧及碱交代溶蚀作用,热液中的大部分U^6+主要被S^2-和Fe^2+等还原剂在浅部相对氧化的环境中还原成矿;给出了一种较简易的物质来源定量方法和铀成矿模式.
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To study the relationship between mental-physical health and coping behavior,job stress and job motivation in medical laboratory scientists and technicians. A cross-section survey was conducted,using the anxiety rating scale(SAS), depression rating scale(SDS), coping behavior rating scale,self-rating subhealth scale,self-rating stress scale,and self-rating job motivation scale among 289 medical laboratory scientists and technicians with analysis of ANOVA and Regression. The study was carried out in three steps:step1 is to analyze the general situation of the mental-physical health.Step 2 is to analyze the features of the main influencial facotors.Step 3 is to study the influence of the relative factors on mental-physical health.The following are the results: 1.The anxiety and depression scores of the medical researchers and technicians were 30±6 and 37±8 respectively,both significantly lower than those of the national norm(34±6 and 42±11 respectively,both P<0.01),which are of significant difference. The depression score of the associate chief technician was 42±7, significantly higher than those of the medical researchers and technicians with any other professional titles (all P<0.05), and the anxiety score of the associate chief technicians was 32±7, significantly higher than that of the research fellows(28±4, P<0.05),with no significant difference to the score of the medical researchers and technicians with other professional titles. The depression score,anxiety score and the subhealth score of the age group of 36~49 were 39±9,31±7 and 32±9 respectively, both higher than that of the age group of 20~35 (36±8,29±6 and 29±7 respectively,both P<0.05),while there is much diference among other age groups. And the subhealth status has nothing to do with marital status,education background and professional titles. 2.The coping behaviors,job stress and motivation of the military medical laboratory scientists and technicians. 1)Coping behaviors:The seeking help score of the associate chief technicians was 2.8±0.5,not significantly different from that of the associate research fellows(2.8±0.5),but significantly lower than those of the medical researchers and technicians with other professional titles(all P<0.01),and whose self-blame score was higher than that of the research fellows,which is of significant difference.The self-blame score and the imagination score of the associate research fellows were 2.0±0.5 and 2.4±0.5 respectively, significantly higher than that of the research fellows(1.6±0.4, 2.1±0.4,both P<0.01). The seeking help score of the females was 3.1±0.5, significantly higher than that of the males(2.9±0.5, both P<0.01),and the solving problem score was 3.4±0.6,significantly lower than the male(3.6±0.7, both P<0.01).There is no any significant difference in coping behaviors among researchers and technicians of different marital status,education background and age groups. 2)Job stress: The score of job stress of the age group of 35~49 and 50~60 were 23±8 and 25±6 respectively,significantly higher than that of the 20~35(21±7,both P<0.05). There is no any significant difference in job stress among researchers and technicians of different marital status,gender,professional titles and education background. 3)The score of meeting personal desire for reputation and interests of the males was 19.6±5.4,significantly higher than that of the females(18.4±5.0, both P<0.05), while there is no significant difference in job motivation among researchers and technicians of different titles,education,age and marital status. 3.The relationship of the mental-physical health of the military medical laboratory scientists and technicians with their coping behaviors,job stress and motivations 1) Coping behaviors:Regression analysis showed that, the best predictors of subhealth were anxiety,depression and escaping (β=-0.40,β=0.23, β=0.14, both P<0.01).the best predictors of anxiety and depression were active coping behaviors and negative coping behaviors (β=-0.40,β=0.40, both P<0.01).The moderate(rational) coping behaviors is the best predictor only of anxiety and of significant difference. 2)job stress : Regression analysis demonstrated that anxiety,depression,job stress 2 and job stress 4 are the best predictor for subhealth;job stress 12 is the best retro-predictor for depression; job stress 3 and 8 are the best predictor for depression;and job stress 2 and 9 are the best predictor for anxiety ,which are of significant difference. 3)Motivation:Regression analysis demonstrated that depression is the best predictor for subhealth while motivation itself doesn't predict subhealth;with respect to the specific contents of motivation,"probing unknown rules and making contributions to the human society "is the best retro-predictor for depression and has nothing to do with anxiety prediction. 4) The combined influences of coping behaviors,job stress and motivations: Regression analysis showed that, the best predictors for subhealth were anxiety,depression and job stress(β=0.41,β=0.24, β=0.19, both P<0.01).the best predictors for anxiety and depression were active coping behaviors and negative coping behaviors (β=-0.40,β=0.40, both P<0.01).The moderate(rational) coping behaviors is the best predictor only for anxiety and of significant difference. CONCLUSIONS: Regression analysis showed that the best predictors for anxiety and depression were active coping behaviors and negative coping behaviors, the best predictors for subhealth were anxiety,depression and job stress.Coping behaviors, job stress and motivations have significant influences on the mental-physical health of the military medical researchers and and technicians. Among them,coping behavior is the most important factor while job stress and motivation follow. Seeking help more often,less self-blame ,imagination and job stress could help release the anxiety, depression and improve the subhealth of the medical researchers and technicians. The findings of this study indicate we should address the physical and mental health of the military laboratory researchers and technicians.