Synthesis and Biological Studies of Novel Aminophosphonates and Their Metal Carbonyl Complexes (Fe,Ru)

The quest to find new inhibitors of biologically relevant targets is considered an important strategy to introduce new drug candidates for the treatment of neurodegenerative diseases. A series of (aminomethyl)benzylphosphonates 8a–c and their metallocarbonyl iron 9a–c and ruthenium 10a–c complexes were designed, synthesized, and evaluated for their inhibitory potentials against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) by determination of IC₅₀. Metallocarbonyl derivatives, in general, did not show significant inhibition activity against these enzymes, the most potent inhibitor was the (aminomethyl)benzylphosphonate 8a (IC₅₀ = 1.215 µM against AChE). Molecular docking analysis of AChE and (aminomethyl)benzylphosphonates 8a–c showed the strongest interactions of 8a and AChE compared to isomers 8b and 8c. Cytotoxicity studies of synthesized compounds towards the V79 cell line were also performed and discussed.     

The structure of late-life depressive symptoms across a 20-year span: A taxometric investigation.

Past studies of the underlying structure of depressive symptoms have yielded mixed results, with some studies supporting a continuous conceptualization and others supporting a categorical one. However, no study has examined this research question with an exclusively older adult sample, despite the potential uniqueness of late-life depressive symptoms. In the present study, the underlying structure of late-life depressive symptoms was examined among a sample of 1,289 individuals across 3 waves of data collection spanning 20 years. The authors employed a taxometric methodology using indicators of depression derived from the Research Diagnostic Criteria (R. L. Spitzer, J. Endicott, & E. Robins, 1978). Maximum eigenvalue analyses and inchworm consistency tests generally supported a categorical conceptualization and identified a group that was primarily characterized by thoughts about death and suicide. However, compared to a categorical depression variable, depressive symptoms treated continuously were generally better predictors of relevant criterion variables. These findings suggest that thoughts of death and suicide may characterize a specific type of late-life depression, yet a continuous conceptualization still typically maximizes the predictive utility of late-life depressive symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

多色点集直线划分的复杂性及其近似算法

多色点集划分研究如何将含有不同颜色点的平面划分为各个区域,每个区域中只包含一种颜色的点。这是计算几何中的一种组合优化问题。但是现有的多边形划分方式性能较差。为此,提出用直线来划分平面。针对平面上多色点集的直线划分,将其离散化,证明其可以被非确定性图灵机在多项式时间内判定。并将Max2SAT问题在多项式时间内归约到组合优化问题,证明多色点集直线划分为NP难,从而证明其是NP完全的。利用最优化版本的特有性质,运用贪心方法构造出多项式时间的近似算法,并L归约到Setcover问题,以此证明算法的近似比为O( lgn)。     

Phenol/Chloroform-Free TiO2-Based miRNA Extraction from Cell Lysate

While microRNAs are considered as excellent biomarkers of various diseases, there are still several remaining challenges regarding their isolation. In this study, we aimed to design a novel RNA isolation method that would help to overcome those challenges. Therefore, we present a novel phenol/chloroform-free, low-cost method for miRNA extraction. Within this method, RNA is extracted from cell lysate with an isopropanol/water/NaCl system, followed by solid-phase extraction using TiO₂ microspheres to effectively separate short RNAs from long RNA molecules. We also demonstrated the pH-dependent selectivity of TiO₂ microspheres towards different sizes of RNA. We were able to regulate the size range of extracted RNAs with simple adjustments in binding conditions used during the solid-phase extraction.     

Tailored Gradient Morphologies and Anisotropic Surface Patterns in Polymer Blends

Gradient morphologies and surface patterns can provide a template for smart materials with tailored local properties. Fabricating such structures in a one‐step melt‐extrusion process will be most beneficial as they usually require several manipulation steps. In this study, gradient morphologies are developed by melt‐spinning matrix‐dispersed polypropylene/polystyrene blends as a template system and dynamic control of their formation is achieved, which further leads to anisotropic surface patterns. Cross and longitudinal sections and the surface of extruded fibers are evaluated by scanning electron microscopy. Distinct microstructure gradients regarding size and shape of the dispersed phase are formed in the bulk. After dissolving the dispersed phase, ordered (sub)micron channels appear on the surface, which are further refined by hot‐drawing. The resulting textures form anisotropic grooves along the fiber axis on the surface, as verified by atomic force microscopy. Capillary theory is applied to elucidate the formation mechanisms of gradient microstructures in polymer blends during processing. It is shown that all these features can be tailor‐made by using the extrusion die as a design tool. By transferring the knowledge to suitable polymer blends and processes, the designed gradient and surface structures can find applications, for instance, in materials with adaptive mechanical or interfacial properties.