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11.
:在 p H3 .50酸性介质中 ,Cu( )和 Fe( )在非离子表面活性剂 Tween-80存在下与 5-Br-PADAP生成有色配合物 .有色配合物最大吸收波长都位于 570 nm处 ;表观摩尔吸光系数分别为 7.96× 1 0 4 L· mol-1· cm-1和 6.3 0× 1 0 4 L· mol-1· cm-1;Cu( )在 0~ 1 3μg/2 5ml,Fe( )在 0~ 1 8μg/2 5ml范围内符合比耳定律 .用拟定的方法测定了铝片和水样中的 Cu( )和 Fe( ) ,结果令人满意  相似文献   
12.
 从代谢组学角度进行慢性阻塞性肺部疾病(COPD)中维西医病证结合的临床研究,解析中维医不同分型间及其与正常人群间代谢表型的构成差异,寻找并鉴定中维医证型的代谢生物标记物,阐述中医肾虚痰瘀证及维医异常黑胆质证在代谢组学方面的共性特征改变及其物质基础,以体现两者在代谢组学方面的交互性,为COPD的诊断、防治提供新的思路和方法奠定一定的基础。首先,按照纳入标准收集COPD稳定期患者105例,进行西医的诊断分级以及中医、维吾尔医的辨证分型,分为中医肾虚痰瘀证组和维医异常黑胆质证组,对所有患者及正常对照组受试者血样分批进行核磁共振技术(NMR)的代谢组学方面的测定和分析;得到健康人与各组COPD患者的血浆一维及二维氢谱,对1H-NMR谱进行分段积分后的积分值进行OPLS-DA分析,得到3D平面分布图,显示COPD患者肾虚痰瘀证组、异常黑胆质证组分别与正常对照组的分布区域完全分开,而中维医二组的分布区域未完全分开,说明两组血浆在代谢成分上无明显差异,同样表现为血桨中多种氨基酸显著降低,差异有统计学意义(P<0.05),其中包括异亮氨酸、亮氨酸、缬氨酸、丙氨酸、谷氨酰胺、酪氨酸、苯丙氨酸。此外,糖蛋白、不饱和脂类及极低密度脂蛋白也较健康人显著降低,差异有统计学意义(P<0.05);而乳酸、肉碱及丙酮、乙酰乙酸较健康人增高,差异有统计学意义(P<0.05);因此COPD二组中维医证患者血浆中代谢紊乱较正常对照组严重,提示氨基酸、蛋白质的代谢异常及脂肪代谢减弱、三大营养物质代谢反复相互影响的程度更重,使代谢紊乱状态更加严重。总之,从代谢组学角度出发,进行COPD中维医病证结合的对比研究,发现肾虚痰瘀证及异常黑胆质证患者代谢组学改变更突出,但两证的代谢组学变化基本一致,其生物表型相似,表现为氨基酸、脂肪及糖代谢异常,提示COPD肾虚痰瘀证与异常黑胆质证患者机体内三大物质代谢紊乱、能量代谢异常,相比健康人显示机体的免疫功能更低下、内分泌功能更紊乱、预后更差。  相似文献   
13.
Galectins are a taxonomically widespread family of glycan-binding proteins, defined by at least one conserved carbohydrate-recognition domain with a canonical amino acid sequence and affinity for beta-galactosides. Because of their anti-adhesive as well as pro-adhesive extracellular functions, galectins appear to be a novel class of adhesion-modulating proteins collectively known as matricellular proteins (which include thrombospondin, SPARC, tenascin, hevin, and disintegrins). Accordingly, galectins can display de-adhesive effects when presented as soluble proteins to cells in a strong adhesive state. In this context, the de-adhesive properties of galectins should be considered as physiologically relevant as the proadhesive effects of these glycan-binding proteins. This article focuses on the roles of mammalian galectins in cell adhesion, spreading, and migration, and the crossregulation of these functions. Although careful attention should be paid when examining individual galectin functions due to overlapping distributions, these intriguing glycan-binding proteins offer promising possibilities for the treatment and intervention of a wide variety of pathological processes, including cancer, inflammation, and autoimmunity.  相似文献   
14.
以3-乙酰基酚酮(1)为原料,与自制的苯基三甲基三溴化胺在四氢呋喃中反应2h后,加水稀释得到甲基上单溴化产物3-(2-溴代乙酰基)酚酮(2)。化合物(2)与取代苯甲醛类化合物(3a-i)在以甲醇为溶剂的条件下,于冰水浴中滴加氢氧化钠溶液,反应3h闭环,酸化后即得类黄酮型缩杂环酮的一系列化合物(4a—i),其中4b—4f是未见报道的新化合物。所有化合物的结构通过红外光谱、液相色谱分析及物理常数的测定得以证实。  相似文献   
15.
从真菌Penicillium sp.M03发酵液中提取到一种具有抗菌活性的肽类物质AF2,并对其性质进行初步研究.真菌发酵液经纱布过滤,离心后经10000 D超滤膜超滤,冻干,以纯水溶解经Sephadex LH-20,DEAE Sepharose及Sephadex G-15进行分离纯化得到纯净物质,并对其基本性质进行研究.结果证明:AF2具有典型的肽类物质特征反应,分子量约为1155,含有12种常见氨基酸,对酸碱,胰蛋白酶,β-内酰胺酶稳定,对热有较好的耐受性.  相似文献   
16.
本文描述了一个实用的小规模的对DCE的实现,它重点强调利用C++及java在语法语义上的极其相似的特点进行了分布式系统前后台的开发工作。本质上,本文是从面积对象的角度,对远程过程调用的实现。  相似文献   
17.
提出了一种基于论域空间降维的机电产品故障诊断方法。通过对粗糙集论域空间进行降维,降低了计算复杂性,在此基础上通过属性约简和值约简,导出了清晰简明的诊断决策规则。运用该方法对镇流器自动化生产线上的故障诊断进行研究,实例分析表明,这种新方法提高了故障诊断的能力,对进行在线故障诊断具有实际应用价值。  相似文献   
18.
Understanding how larvae from extant hydrothermal vent fields colonize neighbouring regions of the mid-ocean ridge system remains a major challenge in oceanic research. Among the factors considered important in the recruitment of deep-sea larvae are metabolic lifespan, the connectivity of the seafloor topography, and the characteristics of the currents. Here we use current velocity measurements from Endeavour ridge to examine the role of topographically constrained circulation on larval transport along-ridge. We show that the dominant tidal and wind-generated currents in the region are strongly attenuated within the rift valley that splits the ridge crest, and that hydrothermal plumes rising from vent fields in the valley drive a steady near-bottom inflow within the valley. Extrapolation of these findings suggests that the suppression of oscillatory currents within rift valleys of mid-ocean ridges shields larvae from cross-axis dispersal into the inhospitable deep ocean. This effect, augmented by plume-driven circulation within rift valleys having active hydrothermal venting, helps retain larvae near their source. Larvae are then exported preferentially down-ridge during regional flow events that intermittently over-ride the currents within the valley.  相似文献   
19.
High-resolution structure of a DNA helix containing mismatched base pairs   总被引:3,自引:0,他引:3  
T Brown  O Kennard  G Kneale  D Rabinovich 《Nature》1985,315(6020):604-606
The concept of complementary base pairing, integral to the double-helical structure of DNA, provides an effective and elegant mechanism for the faithful transmission of genetic information. Implicit in this model, however, is the potential for incorporating non-complementary base pairs (mismatches) during replication or subsequently, for example, during genetic recombination. As such errors are usually damaging to the organism, they are generally detected and repaired. Occasionally, however, the propagation of erroneous copies of the genome confers a selective advantage, leading to genetic variation and evolutionary change. An understanding of the nature of base-pair mismatches at a molecular level, and the effect of incorporation of such errors on the secondary structure of DNA is thus of fundamental importance. We now report the first single-crystal X-ray analysis of a DNA fragment, d(GGGGCTCC), which contains two non-complementary G X T base pairs, and discuss the implications of the results for the in vivo recognition of base-pair mismatches.  相似文献   
20.
根据汽车冷却液储液罐试验台测控系统的要求,设计了基于CAN总线的分布式测控系统.采用具有CAN总线接口的输入/输出模块实现了现场测控,监控室的工业控制计算机通过CAN适配卡与各模块进行通信,详细介绍了测控软件的设计方法.  相似文献   
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