Molecular dynamic simulation of lubricant spreading： effect from the substrate and endbead

Molecular dynamic simulations based on a coarse-grained, bead-spring model are adopted to investigate the spreading of both nonfunctional and functional perfluoropolyether (PFPE) on solid substrates. For nonfunctional PFPE, the spreading generally exhibits a smooth profile with a precursor film. The spreading profiles on different substrates are compared, which indicate that the bead-substrate interaction has a significant effect on the spreading behaviour, especially on the formation of the precursor film. For functional PFPE, the spreading generally exhibits a complicated terraced profile. The spreading profiles with different endbeads are compared, which indicate that the endbead-substrate interaction and the endbead--endbead interaction, especially the latter, have a significant effect on the spreading behaviour.     

The Intervention of Prebiotics on Depression via the Gut–Brain Axis

The imbalance of intestinal microbiota can cause the accumulation of endotoxin in the main circulation system of the human body, which has a great impact on human health. Increased work and life pressure have led to a rise in the number of people falling into depression, which has also reduced their quality of life. The gut–brain axis (GBA) is closely related to the pathological basis of depression, and intestinal microbiota can improve depressive symptoms through GBA. Previous studies have proven that prebiotics can modulate intestinal microbiota and thus participate in human health regulation. We reviewed the regulatory mechanism of intestinal microbiota on depression through GBA, and discussed the effects of prebiotics, including plant polysaccharides and polyphenols on the regulation of intestinal microbiota, providing new clues for the prevention and treatment of depression.     

The Potential Antidepressant Action of Duloxetine Co-Administered with the TAAR1 Receptor Agonist SEP-363856 in Mice

Here, we explored the possible interaction between duloxetine and SEP-363856 (SEP-856) in depression-related reactions. The results showed that oral administration of duloxetine showed powerful antidepressant-like effects in both the forced swimming test (FST) and the suspension tail test (TST). SEP-856 orally administered alone also exerted an antidepressant-like effect in FST and TST, especially at doses of 0.3, 1, and 10 mg/kg. In addition, duloxetine (15 mg/kg) and SEP-856 (15 mg/kg) both showed antidepressant-like effects in the sucrose preference test (SPT). Most importantly, in the above experiments, compared with duloxetine alone, the simultaneous use of duloxetine and SEP-856 caused a more significant antidepressant-like effect. It is worth noting that doses of drug combination in FST and TST did not change the motor activities of mice in the open-field test (OFT). Thus, duloxetine and SEP-856 seem to play a synergistic role in regulating depression-related behaviors and might be beneficial for refractory depression.     

Wetting and dewetting behaviour of hygroscopic liquids: Recent advancements

This review covers the most recent researches on wetting and dewetting phenomena related to the application of hygroscopic liquids in industry and technologies. Hygroscopic liquids actively absorb moisture from the surrounding air; therefore, they are used in the processes required for the moisturizing of surfaces or preventing the icing as well as control of evaporation rate and the humidity. The air humidity and wettability of substrates were shown to be crucial parameters affecting the wetting/dewetting kinetics of hygroscopic liquids. It is the adsorption of moisture on the hydrophilic surface that promotes the formation and spread of the precursor layer. The latter, in turn, is the droplet-spreading driver. The absorption of moisture by the liquid itself gives only a slight effect on wetting. The work devoted to the dewetting of hygroscopic liquids during evaporation, and the influence of thermal effects arising from contact with moist air on the wetting kinetics is also considered.     

关于自由射流计算的两点考虑

本文用Multi-Block算法和标准的κ-ε模型计算轴对称自由射流,计算中发现:(1)不同的纵向网格宽度比(疏密度比)会导致不同的扩张速率的计算结果。(2)在相同的网格疏密度比下,由于不同喷管长度L带来的射流上游进口的湍流结构的变化与下游射流扩张速率有清晰的关联。     

Use of 9,10-diphenylanthracene as a contrast agent in chemiluminescence imaging: The observation of spreading of oxidative degradation in thin polypropylene films

Thin films of polypropylene were doped with a chemiluminescence (CL) activator, 9,10-diphenylanthracene (DPA), and were thermally oxidised in a CL imaging apparatus to determine whether heterogeneous oxidation processes such as spreading of oxidation could be observed. The presence of DPA resulted in significantly more intense CL images compared with undoped polymer, due to the efficient chemically induced electron exchange luminescence reaction between DPA and hydroperoxides. Hence, the CL images from DPA-doped PP were used to locate the position of hydroperoxides in the oxidising polymer. For thermal oxidation at 150 and 140 °C hydroperoxides were observed to form in localised regions of the films, whilst other areas remained hydroperoxide free. As the oxidation time increased the concentration of hydroperoxides in these areas increased and they were observed to spread to the remainder of the polymer. Time-resolved line maps from the images indicated that zones with high concentration of hydroperoxides travel through the polymer during oxidation. Integrals of CL images from the thermal oxidation of DPA-doped polymers indicated that a significant degree of oxidation had occurred by the end of the “induction period” for a conventional CL-intensity oxidation-time profile. This is a likely reason why spreading of oxidation has not previously been observed for undoped PP films.     

聚4—甲基戊烯—1溶液水面展开制备超薄膜的研究

在聚4-甲基戊烯-1(PMP)的环已烷溶液中,加入对水有一定亲合性的第三组分环已酮作为展开助剂,研究了该三组分溶液体系的界面性质与溶液在水面上展开程度的关系。发现环已酮的加入明显降低了PMP溶液对水的界面张力,使得溶液在水面上的展开系数大为增加,得以制备厚度为10～25nm的PMP超薄膜。     

Signaling mechanisms of glucose-induced F-actin remodeling in pancreatic islet β cells

The maintenance of whole-body glucose homeostasis is critical for survival, and is controlled by the coordination of multiple organs and endocrine systems. Pancreatic islet β cells secrete insulin in response to nutrient stimuli, and insulin then travels through the circulation promoting glucose uptake into insulin-responsive tissues such as liver, skeletal muscle and adipose. Many of the genes identified in human genome-wide association studies of diabetic individuals are directly associated with β cell survival and function, giving credence to the idea that β-cell dysfunction is central to the development of type 2 diabetes. As such, investigations into the mechanisms by which β cells sense glucose and secrete insulin in a regulated manner are a major focus of current diabetes research. In particular, recent discoveries of the detailed role and requirements for reorganization/remodeling of filamentous actin (F-actin) in the regulation of insulin release from the β cell have appeared at the forefront of islet function research, having lapsed in prior years due to technical limitations. Recent advances in live-cell imaging and specialized reagents have revealed localized F-actin remodeling to be a requisite for the normal biphasic pattern of nutrient-stimulated insulin secretion. This review will provide an historical look at the emergent focus on the role of the actin cytoskeleton and its regulation of insulin secretion, leading up to the cutting-edge research in progress in the field today.     

Capillary electrophoresis study of systemin peptides spreading in tomato plant

Systemin (Sys) is an 18‐aa plant peptide hormone involved in the regulation of plant's defensive response. Sys is considered as a fast‐spreading systemic wound signal. We developed a simple and rapid CE method to monitor the spreading of Sys peptides through tomato plant. A 1,2,3‐triazole‐linked AZT‐systemin conjugate was designed as a model to study the possibility of translocating small cargo molecules 3'‐Azido‐2',3'‐dideoxythymidine by systemin. The Sys peptides (Sys, N‐propiolyl Sys, and AZT‐systemin conjugate) were injected into the stem and leaves of mature tomato plant. Its transportation throughout the plant tissue was traced by CE. The peptides were clearly visible in the crude tomato exudates and an optimum separation was achieved in 25 mM phosphate “buffer” at pH 2.5 and a voltage of 20 kV using uncoated fused silica capillary. CE analysis showed that Sys peptides are well separated from tomato plant exudates ingredients and are stable in tomato stem and leaf exudates for up to 24 h. CE study revealed that the Sys peptides are effectively spreading throughout tomato stem and leaves and the peptides could be directly detected in the crude plant matrixes. The translocation was strongly inhibited by sodium azide. The results showed that the established CE method can be used to characterize plant peptides spreading under plant physiological conditions.