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21.
Many pathogenic bacteria require flagella-mediated motility to colonise and persist in their hosts. Helicobacter pylori and Campylobacter jejuni are flagellated epsilonproteobacteria associated with several human pathologies, including gastritis, acute diarrhea, gastric carcinoma and neurological disorders. In both species, glycosylation of flagellin with an unusual sugar pseudaminic acid (Pse) plays a crucial role in the biosynthesis of functional flagella, and thereby in bacterial motility and pathogenesis. Pse is found only in pathogenic bacteria. Its biosynthesis via six consecutive enzymatic steps has been extensively studied in H. pylori and C. jejuni. This review highlights the importance of flagella glycosylation and details structural insights into the enzymes in the Pse pathway obtained via a combination of biochemical, crystallographic, and mutagenesis studies of the enzyme–substrate and –inhibitor complexes. It is anticipated that understanding the underlying structural and molecular basis of the catalytic mechanisms of the Pse-synthesising enzymes will pave the way for the development of novel antimicrobials.  相似文献   
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This paper presents the development of dynamic simulation of a flexible plate structure with various boundary conditions. A flexible square plate is considered. A finite-difference method is used to discretise the governing partial differential equation formulation describing its dynamic behaviour. The model thus developed has been validated against characteristic parameters of the plate. The model thus developed is further formulated using discrete state-space representation, to allow easy and fast implementation for simulating the dynamic behaviour of the plate with various boundary conditions. The simulation algorithm thus developed is validated, and accurate results with representation of the first five modes of vibration of the plate have been achieved. The algorithm thus developed is used in subsequent research work as a platform for development and verification of suitable control strategies for vibration suppression of flexible plate structures.  相似文献   
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Prolactin inducible protein (PIP) is a 17- kDa single polypeptide chain, known by various names due to its versatile nature and function in human reproductive and immunological systems. It is expressed in several exocrine tissues such as the lacrimal, salivary, and sweat glands. Its expression is up regulated by prolactin and androgens, and estrogens down regulate it. Due to its over-expression in metastatic breast and prostate cancer, presently PIP is considered as a prognostic biomarker. Moreover, its aspartyl-proteinase nature suggests its role in tumor progression. PIP has unique features because it is small in size and plays multiple important functions. Its ability to bind potentially with CD4-T cell receptor, immunoglobulin G (IgG), actin, zinc α2-glycoprotein (ZAG), fibronectin and enamel pellicle, reveals its important biological functions. This is the first comprehensive review on the structure and functional analysis of PIP and its clinical applications. Received 04 August 2008; received after revision 09 September 2008; accepted 15 September 2008  相似文献   
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Socioeconomic status is commonly conceptualized as the social standing or well‐being of an individual or society. Higher socioeconomic status has long been identified as a contributing factor for mortality improvement. This paper studies the impact of macroeconomic fluctuations (having gross domestic product (GDP) as a proxy) on mortality for the nine most populous eurozone countries. Based on the statistical analysis between the time‐dependent indicator of the Lee and Carter (Journal of the American Statistical Association, 1992, 87(419), 659–671) model and GDP, and adaptation of the good features of the O'Hare and Li (Insurance: Mathematics and Economics, 2012, 50, 12–25) model, a new mortality model including this additional economic‐related factor is proposed. Results for male and female from ages between 0 and 89, and similar for unisex data, are provided. This new model shows a better fitting and more plausible forecast among a significant number of eurozone countries. An in‐depth analysis of our findings is provided to give a better understanding of the relationship between mortality and GDP fluctuations.  相似文献   
25.
目的观察肉毒毒素A(BoNT-A)对L5、L6脊神经结扎引起慢性神经源性疼痛模型大鼠行为学的影响。方法建立Wistar大鼠左侧L5、L6脊神经结扎模型(SNL模型)。SNL模型大鼠随机分为3组(n=8)。1)实验组:SNL术后第3天同侧足底皮下注射BoNT-A30U/kg;2)对照组:SNL术后同侧足底皮下注射相同容积生理盐水;3)假手术组:仅暴露而不结扎L5和L6脊神经。均分别测定术前、给药前、给药后1d、3d、5d、7d、14d、21d的机械缩足反射阈值(MWT)和热缩足反射潜伏期(TWL)。结果实验组手术同侧足底皮下注射BoNT-A可以增加大鼠的MWT和TWL,实验组手术对侧、对照组、假手术组应用BoNT-A对MWT和TWL无影响。结论足底皮下注射BoNTA能够改善SNL模型大鼠手术同侧肢体的MWT和TWL,有镇痛作用。  相似文献   
26.
This paper explains cross‐market variations in the degree of return predictability using the extreme bounds analysis (EBA). The EBA addresses model uncertainty in identifying robust determinant(s) of cross‐sectional return predictability. Additionally, the paper develops two profitable trading strategies based on return predictability evidence. The result reveals that among the 13 determinants of the cross‐sectional variation of return predictability, only value of stock traded (a measure of liquidity) is found to have robust explanatory power by Leamer's (1985) EBA. However, Sala‐i‐Martin's (1997) EBA reports that value of stock traded, gross domestic product (GDP) per capita, level of information and communication technology (ICT) development, governance quality, and corruption perception are robust determinants. We further find that a strategy of buying (selling) aggregate market portfolios of the countries with the highest positive (negative) return predictability statistic in the past 24 months generates statistically significant positive returns in the subsequent 3 to 12 months. In the individual country level, a trading rule of buying (selling) the respective country's aggregate market portfolio, when the return predictability statistic turns out positive (negative), outperforms the conventional buy‐and‐hold strategy for many countries.  相似文献   
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This paper reports the synthesis of CTAB mediated CSA doped PANI and GN/GNP@ PANI composite nanofibers. The as synthesized composite nanofibers were examined by TEM, SEM, XRD, Raman spectroscopy; UV–visible diffused reflectance spectroscopy and TGA. The CTAB mediated CSA doped composite nanofibers showed 59% higher DC electrical conductivity at ambient temperature than that of PANI,which might be due to the enhancement in the mobility of the charge carriers and reduction in hopping distance in the composite system. The CTAB mediated CSA doped composite nanofibers compared to PANI was observed to be showing enhanced DC electrical conductivity retention after various cycles of heating, suggesting an enhancement in thermal stability of the composite structure, which could be attributed to the synergistic effect of GN,GNP and PANI. Additionally, the composite nanofibers showed greater electrochemical activity and better capacitive performance and reduced optical bandgap than that of PANI.  相似文献   
30.
Synthesis of organosilanes from alkenes is a very important topic owing to their wide applications.A Ni/Cu dual metal-catalyzed arylsilylation of terminal alken...  相似文献   
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