水分去除的方法及其在药物合成中的应用

化学药合成过程中水分残留不利于反应的进行,还影响药物及制剂的稳定性、理化性质、溶出及药理作用等,因此水分几乎是大多数药物合成中的必测项目,通过有效除水严格控制反应体系中水分的含量至关重要。本文综述了水分的存在形式,常见除水剂和脱水剂的种类、作用原理与除水能力,以及在药物合成的应用,为药物合成反应中水分的去除提供参考。     

The Relationship between Self-Efficacy,Functional Exercise Capacity and Physical Activity in People with COPD: A Systematic Review and Meta-Analyses

Abstract

The purpose of this study was to investigate the strength of the relationships between self-efficacy and (i) functional exercise capacity and (ii) physical activity in chronic obstructive pulmonary disease (COPD), and whether self-efficacy assessment type (i.e., COPD symptoms, exercise-task, exercise-barrier, general, falls) and physical activity assessment type (i.e., self-report vs. objective) are moderators. A systematic search of COPD and self-efficacy concepts was conducted using eight databases from inception to 23 January 2019. Studies were included if they provided correlation coefficients of the relationship between self-efficacy and functional exercise capacity or physical activity, were conducted in adults diagnosed with COPD, and were published in English-language journals. A total of 14 correlation coefficients were included in the self-efficacy and functional exercise capacity meta-analysis, and 16 in the self-efficacy and physical activity meta-analysis. Data were screened, reviewed, and extracted independently by two reviewers, with discrepancies resolved by a third reviewer. Stronger self-efficacy was associated with better functional exercise capacity (weighted r?=?0.38, 95%CI [0.25, 0.50]), and greater physical activity (weighted r?=?0.25, 95%CI [0.17, 0.34]). Exercise-task self-efficacy had the strongest relationship to functional exercise capacity (weighted r?=?0.64, 95% CI [0.51, 0.73]). For physical activity, the type of self-efficacy most strongly related was inconclusive. In COPD, self-efficacy has a relationship to functional exercise capacity and physical activity, the strength of which is influenced by the choice of self-efficacy measure. An understanding of these relationships will assist clinicians in selecting the self-efficacy measure most closely related to the outcome of interest.     

Free Water Loss–induced Heterogeneous Residual Strain and Reduced Fatigue Resistance in Root Dentin: A 3-dimensional Digital Image Correlation Analysis

IntroductionThis study evaluated free water loss–induced residual strain with and without axial compressive loading and assessed the mechanical effect of cyclic loading in fully hydrated and partially dehydrated root dentin.MethodsRoot dentin sections prepared from freshly extracted human premolars were used. Customized 3-dimensional digital image correlation was used to qualitatively and quantitatively analyze the residual strain induced by 2 hours of free water loss in different regions of root dentin. Residual strain in partially dehydrated root dentin during axial compressive loading was also analyzed using 3-dimensional digital image correlation. The effect of cyclic loading on load to fracture in fully hydrated and partially dehydrated dentin and their fractography were analyzed using micro–computed tomographic imaging.ResultsFree water loss resulted in a heterogeneous distribution of residual strain and an overall formation of residual compressive strain with areas of tensile strain localized to the root canal and outer dentin. More residual compressive strain was observed in the apical dentin compared with the cervical dentin (P < .05), and more residual shear strain was observed in outer dentin compared with inner dentin (P < .05). Axial loading resulted in an increase in the load-induced compressive strain in the direction perpendicular to dentinal tubules (P < .05). Fully hydrated roots displayed a higher mean (P < .05) and median (P < .05) number of cycles to fracture with microcracks characteristic of toughness.ConclusionsAfter free water loss, root dentin displayed an increased formation of heterogenous residual strain, which resulted in increased axial compressive load-induced strain and a decreased resistance to fatigue failure. The effect of free water loss in the loss of mechanical integrity of root-filled teeth needs further investigation.     

基于生物活性与效应基准的中药质量 评价技术发展现状与展望

中药质量的评控问题是制约中药现代化发展的瓶颈,因此有必要在现有检测方法的基础上结合生物评价,继而更为全面地保证中药质量。生物评价是完善中药质量标准、保证临床功效和安全性评价的重要方法,已成为中药质量标准化发展趋势之一。在此处主要论述了近年来基于生物活性与效应基准的中药质量评价技术和已取得的部分研究进展,同时对目前中药质量生物评价研究与应用中存在的主要问题进行探讨,进一步对其未来应用做出展望,从而更好的对中药质量进行控制。     

Approximation of diffuse attenuation,Kd, for MODIS high-resolution bands

A high resolution depth attenuation product (K_d^hires) was developed using MODIS 500 m and 250 m spectral bands. The K_d^hires was compared with Wang’s operational K_d for the Chesapeake Bay. Minimal differences were observed between the two methods, with greatest deviation occurring in areas of high turbidity in the tributaries. After tuning the new K_d^hires, the mean absolute error and bias between the two algorithms was 0.22 m^?1 and 0.026 m^?1, indicating good agreement. Higher spatial resolution provides for improved retrievals along the coast and into the narrow sections of the tributaries, coinciding with areas of concern to estuarine health and coastal management applications.     

Antimicrobial activities of novel bipyridine compounds produced by a new strain of Saccharothrix isolated from Saharan soil

The actinobacterium strain ABH26 closely related to Saccharothrix xinjiangensis, isolated from an Algerian Saharan soil sample, exhibited highly antagonist activity against Gram-positive bacteria, yeasts and filamentous fungi. Its ability to produce antimicrobial compounds was investigated using several solid culture media. The highest antimicrobial activity was obtained on Bennett medium. The antibiotics secreted by strain ABH26 on Bennett medium were extracted by methanol and purified by reverse-phase HPLC using a C18 column. The chemical structures of the compounds were determined after spectroscopic (¹H NMR, ¹³C NMR, ¹H-¹H COSY and ¹H-¹³C HMBC spectra), and spectrometric (mass spectrum) analyses. Two new cyanogriside antibiotics named cyanogriside I (1) and cyanogriside J (2), were characterized along with three known caerulomycins, caerulomycin A (3), caerulomycin F (4) and caerulomycinonitrile (5). This is the first report of cyanogrisides and caerulomycins production by a member of the Saccharothrix genus. The minimum inhibitory concentrations (MIC) of these antibiotics were determined against pathogenic microorganisms.