A Comprehensive Review with Updated Future Perspectives on the Ethnomedicinal and Pharmacological Aspects of Moringa oleifera

Moringa oleifera is an ancient remedy plant, known as the miraculous plant due to its many prominent uses and significant health benefits. It is a nutrient-rich plant, with exceptional bioactive compounds, such as polyphenols that possess several medicinal properties. Many significant studies have been carried out to evaluate the ethnomedicinal and pharmacological properties of M. oleifera in various applications. Therefore, this comprehensive review compiles and summarizes important findings from recent studies on the potential properties of different parts of M. oleifera. The pharmacological properties of M. oleifera have been studied for various potential biological properties, such as cardio-protective, anti-oxidative, antiviral, antibacterial, anti-diabetic and anti-carcinogenic effects. Therefore, the potential of this plant is even more anticipated. This review also highlights the safety and toxicity effects of M. oleifera treatment at various doses, including in vitro, in vivo and clinical trials from human studies.     

Electrochemical oxidative rearrangement of tetrahydro-β-carbolines in a zero-gap flow cell

Oxidative rearrangement of tetrahydro-β-carbolines (THβCs) is one of the most efficient methods for the synthesis of biologically active spirooxindoles, including natural products and drug molecules. Here, we report the first electrochemical approach to achieve this important organic transformation in a flow cell. The key to the high efficiency was the use of a multifunctional LiBr electrolyte, where the bromide (Br⁻) ion acts as a mediator and catalyst and lithium ion (Li⁺) acts as a likely hydrophilic spectator, which might considerably reduce diffusion of THβCs into the double layer and thus prevent possible nonselective electrode oxidation of indoles. Additionally, we build a zero-gap flow cell to speed up mass transport and minimize concentration polarization, simultaneously achieving a high faradaic efficiency (FE) of 96% and an outstanding productivity of 0.144 mmol (h⁻¹ cm⁻²). This electrochemical method is demonstrated with twenty substrates, offering a general, green path towards bioactive spirooxindoles without using hazardous oxidants.

A zero-gap flow cell was designed for the first electro-oxidative rearrangement of tetrahydro-β-carbolines to spirooxindoles with high yield, faradaic efficiency and productivity when LiBr was discovered as a bi-functional mediator and catalyst.     

反相微乳液法制备纳米Ag2S增感剂的化学增感研究

本文用反相微乳液法制备了纳米Ag₂S,并用作卤化银乳剂的硫增感剂,研究了其增感效果、增感规律及可能的增感机理.反相微乳液由异辛烷、表面活性剂AOT钠盐和水形成;制得的Ag₂S粒径3—5 nm;用制得颗粒增感卤化银乳剂,获得的感光性能优越于用Na₂S₂O₃水溶液增感;增感规律的研究表明,随着乳剂中纳米Ag₂S浓度的增加,模型乳剂感光度迅速提高、灰雾变化不大,并在100—200μmol/molAg左右获得最佳感光性能,进一步增加浓度则感光度呈下降趋势、灰雾升高;获得最佳感光性能所需的化学增感时间很短,约40分钟,之后感光度不再增加、灰雾上升;用漫反射光谱(DRS)作探针,跟踪记录增感时卤化银微晶表面上纳米Ag₂S增感剂颗粒的演变,为新型纳米增感剂的优异增感特性提供了机理性解释.     

Cloning,Expression, Purification,and Characterization of β-Galactosidase from Bifidobacterium longum and Bifidobacterium pseudocatenulatum

Expression and purification of β-galactosidases derived from Bifidobacterium provide a new resource for efficient lactose hydrolysis and lactose intolerance alleviation. Here, we cloned and expressed two β-galactosidases derived from Bifidobacterium. The optimal pH for BLGLB1 was 5.5, and the optimal temperature was 45 °C, at which the enzyme activity of BLGLB1 was higher than that of commercial enzyme E (300 ± 3.6 U/mg) under its optimal conditions, reaching 2200 ± 15 U/mg. The optimal pH and temperature for BPGLB1 were 6.0 and 45 °C, respectively, and the enzyme activity (0.58 ± 0.03 U/mg) under optimum conditions was significantly lower than that of BLGLB1. The structures of the two β-galactosidase were similar, with all known key sites conserved. When o-nitrophenyl-β-D-galactoside (oNPG) was used as an enzyme reaction substrate, the maximum reaction velocity (V_max) for BLGLB1 and BPGLB1 was 3700 ± 100 U/mg and 1.1 ± 0.1 U/mg, respectively. The kinetic constant (K_m) of BLGLB1 and BPGLB1 was 1.9 ± 0.1 and 1.3 ± 0.3 mmol/L, respectively. The respective catalytic constant (k_cat) of BLGLB1 and BPGLB1 was 1700 ± 40 s⁻¹ and 0.5 ± 0.02 s⁻¹, respectively; the respective k_cat/K_m value of BLGLB1 and BPGLB1 was 870 L/(mmol∙s) and 0.36 L/(mmol∙s), respectively. The K_m, k_cat and V_max values of BLGLB1 were superior to those of earlier reported β-galactosidase derived from Bifidobacterium. Overall, BLGLB1 has potential application in the food industry.     

HCV全基因组培养细胞的比较蛋白组学研究

利用比较蛋白质组技术研究了转染丙型肝炎病毒(Hepatitis C virus, HCV)全基因组的人肝癌细胞系Huh7细胞模型中蛋白质表达谱的变化, 建立了Huh7-HCV的双向凝胶电泳蛋白质表达图谱和数据库. 通过双向凝胶电泳分离和图像分析, 对表达差异2倍以上蛋白质点进行了胶内酶解和MALDI-TOF MS鉴定. 得到包括与细胞骨架蛋白、细胞周期、凋亡和信号转导等相关的14个蛋白质, 并且用Western blot验证了热休克蛋白70的蛋白质组研究结果. 利用HCV全基因组培养系统, 采用蛋白质组学技术, 为研究HCV病毒和宿主细胞相互作用提供了新的实验数据, 为深入研究HCV病毒复制和分子致病机理奠定了基础.     

HL-2A装置上边界间歇性事件与湍流粒子输运的统计学研究

通过对粒子概率分布函数的计算,发现在高等离子体密度下边界间歇性事件的爆发频率有所增加。通过条件平均的手段,正负间歇性事件得以区分,并发现了二者在空间上的不同特征。不同密度梯度下的湍流粒子输运计算表明,间歇性事件与湍流粒子输运之间存在密切联系,间歇性事件的存在能够大大增加湍流粒子输运的大小。在高等离子体密度时,间歇性事件的强度有所增加,而与之相应地,湍流粒子输运的大小也有所增强。     

跌落冲击载荷下焊锡接点金属间化合物层的动态开裂

跌落冲击载荷作用下,含铅焊锡接点与无铅焊锡接点的破坏模式明显不同,而导致这种差异的原因目前尚不明朗.论文提出了一种可用于模拟焊锡接点在跌落冲击载荷下破坏行为的有限元模型,此模型中,金属间化合物(IMC)与焊料间的界面采用粘性区模型(CZM)来模拟其损伤开裂过程,而IMC层内的破坏程度则通过计算其能量释放率来判断.通过对板级封装跌落冲击过程的数值模拟发现,与无铅焊锡接点(Sn3.5Ag)相比,含铅焊锡接点(Sn37Pb)与IMC间的CZM层更容易发生损伤破坏,而该层的开裂会减小IMC层的应力,即降低了其内部的开裂驱动力,从而缓解了IMC层裂纹的起始和扩展.     

2D-C/SiC拉伸损伤的声发射信号聚类分析

对2D-C/SiC复合材料进行常温拉伸试验,利用声发射(AE)仪在线监测其损伤过程.应用K-均值聚类算法对AE信号进行模式识别,结合扫描电镜观察,发现2IC/SiC复合材料拉伸过程的损伤模式包括基体开裂、界面层脱粘、层间剥离、纤维断裂以及纤维束断裂等,并得到了各种损伤模式AE信号参数的中心值.通过对不同损伤模式AE累积事件数和累积能量随时间变化的统计分析,描述了2DC/SiC复合材料拉伸损伤演化过程.     

新型缓变锥型PCF结构接口耦合损耗特性

提出一种新型的缓变锥型光纤接口器件。该接口器件是一个长度为150 mm左右的缓变锥型光子晶体光纤。利用有限元方法对模场直径差别较大的不同光纤进行拼接时的损耗问题进行研究。研究结果表明：在模场直径分别为9 m和10.4 m的光纤之间加入锥型光纤后可以有效降低耦合损耗,并且在不同波长下耦合损耗都维持在一个较低水平。因此,该接口器件能够实现光纤拼接时物理结构的过渡和不同模场直径的转换,从而使拼接损耗降到最低。     

多模调制曲面超精密加工轨迹优化技术

研究了采用单点金刚石超精密车削加工技术(SPDT)加工多模调制曲面过程中的刀具轨迹优化方法,首先,分析了SPDT方法加工多模调制曲面的基本原理;其次,理论分析了平行弦双圆弧插补算法的基本原理,推导了插补误差计算公式。在此基础上,提出采用插补步长伸缩变化方式实现了插补误差的动态控制,并获得了完整的插补计算公式;最后,采用Matlab软件对该插补算法进行了实例仿真分析,并分别与直线插补算法和固定步长双圆弧插补算法进行了对比分析,结果表明,该方法能在保证插补允差的前提下最大程度的减少插补区间数,从而有助于提高加工效率和延长刀具寿命。该方法在调制靶金属模板的制备中获得了广泛应用。