Effects of graft length and density of well‐defined graft polymers on the thermoresponsive behavior and self‐assembly morphology

A series of well‐defined thermoresponsive graft polymers with different lengths and graft densities, poly(glycidyl methacrylate)‐graft‐poly(N‐isopropylacrylate) (PGMA‐g‐PNIPAM), were successfully prepared by combination of controlled/living free radical polymerization and click chemistry. Effects of grafting length and density on the thermoresponsive behavior, aggregating mean diameter, and self‐assembly morphology are systematically investigated. The thermosensitive characteristics of graft polymers in aqueous solution prove that the length and graft density had positive co‐relationship with the lower critical solution temperature value and mean diameter of micelles as well as the size distribution, while the effect of graft length of polymers is more significant than that of density. Transmission electron microscopy analysis shows that the conformations of PGMA₄₅‐g‐PNIPAM₂₀ and PGMA₄₅‐g‐PNIPAM₄₆ with longer length and bigger grafting density in aqueous solutions are spherical nanoparticles with the increasing trend of the diameters, while that of PGMA₄₅‐g‐PNIPAM_{(73, 50%)} shows a spherical‐like morphology, which indicates that the graft length and density have a significant effect on the mean diameter of micelle but not on the self‐assembly morphology. These results reveal that to obtain desired thermoresponsive behavior and self‐assembly morphology of functional polymers, it is essential to design and fabricate the structure of graft polymers with proper length and graft density. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2442–2453     

How does time spent on WeChat bolster subjective well-being through social integration and social capital?

Although WeChat has recently spawned significant resolutions in technology-mediated social contact and interpersonal communication, the research regarding the social and psychological impacts of the newly emerging technology is relatively few. The primary purpose of the current empirical research is to unearth whether and how WeChat interaction could enhance overseas students’ sense of subjective well-being by concentrating on social integration, bridging relationships, and bonding relationships. Using web-based data of 228 Chinese subjects, the obtained results reveal that the time spent on WeChat significantly and directly impacts users’ subjective well-being. Additionally, the findings demonstrate that social integration, bridging relationships, bonding relationships are all significant predictors to subjective well-being. Furthermore, the perceptions of social integration and social capital could play the crucial mediating roles in the connection between WeChat use and the dependent variable of subjective well-being. Therefore, these outcomes may shed light on a more nuanced comprehending of the influence of the new social media interaction on sojourner’s social adaption and overall life quality in the digital age.     

Nanosized Carbon Macrocycles Based on a Planar Chiral Pseudo Meta-[2.2]Paracyclophane

Structural designs combining cycloparaphenylenes (CPPs) backbone with planar chiral [2.2]paracyclophane ([2.2]PCP) lead to optical-active chiral macrocycles with intriguing properties. X-ray crystal analysis revealed aesthetic necklace-shaped structures and size-dependent packages with long-range channels. The macrocycles exhibit unique photophysical properties with high fluorescence quantum yield of up to 82 %, and the fluorescent color varies with ring size. In addition, size-dependent chiroptical properties with moderately large CPL dissymmetry factor of 10⁻³ and CPL brightness in the range of 30–40 M⁻¹ cm⁻¹ were observed.     

Synthesis of a highly active amino‐functionalized Fe3O4@SiO2/APTS/Ru magnetic nanocomposite catalyst for hydrogenation reactions

An amino‐functionalized silica‐coated Fe₃O₄ nanocomposite (Fe₃O₄@SiO₂/APTS) was synthesized. The Fe₃O₄@SiO₂ microspheres possessed a well‐defined core–shell structure, uniform sizes and high magnetization. An immobilized ruthenium nanoparticle catalyst (Fe₃O₄@SiO₂/APTS/Ru) was obtained after coordination and reduction of Ru³⁺ on the Fe₃O₄@SiO₂/APTS nanocomposite. The Ru nanoparticles were not only ultra‐small with nearly monodisperse sizes but also had strong affinity with the surface of Fe₃O₄@SiO₂/APTS. The obtained catalyst exhibited excellent catalytic performance for the hydrogenation of a variety of aromatic nitro compounds, even at room temperature. Moreover, Fe₃O₄@SiO₂/APTS/Ru was easily recovered using a magnetic field and directly reused for at least five cycles without significant loss of its activity.     

An Inexact Modified Newton Method for Viscc and Application in Grasping Force

Acta Mathematicae Applicatae Sinica, English Series - For the variational inequality with symmetric cone constraints problem, we consider using the inexact modified Newton method to efficiently...     

High Performance of PVA Nanocomposite Reinforced by Janus-like Asymmetrically Oxidized Graphene: Synergetic Effect of H-bonding Interaction and Interfacial Crystallization

Chinese Journal of Polymer Science - Macromolecule nanocrystal network and strong interfacial interaction are always beneficial to enhance the mechanical property of polymer-based nanocomposites....     

Synthesis of S-monofluoromethyl phosphorothioates from PⅤ-H compounds and PhSO2SCH2F

S-Monofluoromethyl phosphorothioates represent an important class of organofluorine compounds and are re ported here for the first time.A series of S-monofluoromethyl phosphorothioates are conveniently synthesized from different P^Ⅴ-H compounds and PhSO₂SCH₂F under mild conditions.The method is compatible with common functional groups and provides potential opportunities to synthesize new bioactive molecules for medicinal chemistry.     

Quantification of complanatoside A in rat plasma using LC‐MS/MS and its application to a pharmacokinetic study

Complanatoside A is a flavonol glycoside isolated from Astragalus complanatus, and currently it is used as a quality control index for A. complanatus in the 2010 edition of the Chinese Pharmacopoeia. For the first time, a simple and sensitive LC‐MS/MS method was developed for the determination of complanatoside A in rat plasma over the range of 2.3–575 ng/mL. Complanatoside A was extracted from plasma by a protein precipitation procedure, separated by LC and detected by MS/MS in positive electrospray ionization mode. The method was validated for selectivity, carryover, sensitivity, linearity, extraction recovery, matrix effect, accuracy, precision and stability studies. The lower limit of quantification was established at 2.3 ng/mL. Intra‐ and inter‐day precisions (LLOQ, low‐QC, med‐QC and high‐QC) were <7.9%, and accuracies were between 94.0 and 105.1%. Matrix effect was acceptable (97.9–103.0%) and extraction recovery was reproducible (88.5–94.4%). Complanatoside A was stable in the investigated conditions. The method was applied to the pharmacokinetics of complanatoside A in rats. Copyright © 2015 John Wiley & Sons, Ltd.