Cx43 Promotes Endothelial Cell Migration and Angiogenesis via the Tyrosine Phosphatase SHP-2

The gap junction protein connexin 43 (Cx43) is associated with increased cell migration and to related changes of the actin cytoskeleton, which is mediated via its C-terminal cytoplasmic tail and is independent of its channel function. Cx43 has been shown to possess an angiogenic potential, however, the role of Cx43 in endothelial cell migration has not yet been investigated. Here, we found that the knock-down of Cx43 by siRNA in human microvascular endothelial cells (HMEC) reduces migration, as assessed by a wound assay in vitro and impaired aortic vessel sprouting ex vivo. Immunoprecipitation of Cx43 revealed an interaction with the tyrosine phosphatase SHP-2, which enhanced its phosphatase activity, as observed in Cx43 expressing HeLa cells compared to cells treated with an empty vector. Interestingly, the expression of a dominant negative substrate trapping mutant SHP-2 (CS) in HMEC, via lentiviral transduction, also impaired endothelial migration to a similar extent as Cx43 siRNA compared to SHP-2 WT. Moreover, the reduction in endothelial migration upon Cx43 siRNA could not be rescued by the introduction of a constitutively active SHP-2 construct (EA). Our data demonstrate that Cx43 and SHP-2 mediate endothelial cell migration, revealing a novel interaction between Cx43 and SHP-2, which is essential for this process.     

Studies in Carbohydrate Based Glues and Thickeners for Foodstuffs. Part I: Glucose - Sucrose - Apple Pectin Ternary System

Viscosities are given of aqueous solutions of α-D-glucose, sucrose, apple pectin and Arabic gum, as well as of various binary mixtures of these solutions. Aqueous mixtures of α-D-glucose and sucrose exhibit a small increase in viscosity. The addition of apple pectin to the binary mixtures gives solutions of a viscosity of Arabic gum.     

Extrusion-Grafting Starch Onto Vinylic Polymers

The review outlines the rationale behind starch polymer based thermoplastic resin production using reactive extrusion processing techniques, as well as characterization of these polymers.     

Viscoelastic and thermal properties of natural rubber low-density polyethylene composites with boric acid and borax

The influence of boric acid (BA) and borax (BO) neutron-absorbing fillers on thermal stability and viscoelastic behavior of natural rubber (NR) low-density polyethylene composites has been studied. The thermal degradation and dynamic mechanical properties of the composites have been analyzed as a function of temperature. The results revealed the enhancement of thermal stability of the composites by the addition of BA and BO fillers. The flame resistance of the material was improved by the addition of both the fillers. The storage modulus was found to be dependent upon the temperature and nature of the filler. The amount of NR chains immobilized by filler particles has been quantified from dynamic mechanical analysis and secondary filler/filler interactions have been verified by the Payne effect analysis. Finally, the experimental results have been compared with theoretical predictions.     

Transport and solvent sensing characteristics of styrene butadiene rubber nanocomposites containing imidazolium ionic liquid modified carbon nanotubes

Obtaining strong interfacial interaction between filler and polymer matrix is very crucial for the fabrication of polymer nanocomposites with superior performance. Present study is aimed to fabricate high performance styrene butadiene rubber (SBR) nanocomposites with imidazolium type ionic liquid modified multiwalled carbon nanotube (MWCNT). Ionic liquid facilitates the dispersion of MWCNT in rubber matrix and it is obvious from transmission electron microscopy images. Diffusion of toluene through SBR nanocomposite membranes has been investigated as a function of surface modified MWCNT (f-MWCNT) content to analyze the chain dynamics and filler-polymer interactions. O₂ gas barrier effect of nanocomposites with special reference to the filler loading is explored. The substantial improvement in the barrier effect in presence of filler interpreted on the grounds of a theoretical model describing permeability of heterogeneous systems. Finally solvent sensing characteristics of prepared nanocomposites are also analyzed and it is observed that prepared nanocomposites can be used as a flexible solvent sensor.     

Chitosan/clay nanocomposite film preparation and characterization

Nanocomposites of chitosan and nanoclays (MMT‐Na⁺ and Cloisite 30B) were prepared by solvent casting. The structural properties, thermal behaviors, and mechanical properties were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy, differential scanning calorimetry, thermogravimetry analyses, and an Instron universal testing machine. XRD and TEM results indicated that an exfoliated structure was formed with addition of small amounts of MMT‐Na⁺ to the chitosan matrix. Intercalation along with some exfoliation occurred with up to 5 wt % MMT‐Na⁺. Micro‐scale composite (tactoids) formed when Cloisite 30B was added to the chitosan matrix. Surface roughness increased with addition of a small amount of clay. Tensile strength of a chitosan film was enhanced and elongation‐at‐break decreased with addition of clay into the chitosan matrix. Melt behavior and thermal stability did not change significantly with addition of clays. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1684–1691, 2006     

Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. IX. Alkylierungen mit 2,2,4-Trimethylpentan (Isooctan)

Acid-catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. IX. Alkylations with 2,2,4-Trimethylpentane (Isooctane) The non-conventional alkylation of benzene, toluene, ethyl- and isopropylbenzene, fluoro- and chlorobenzene with 2,2,4-trimethylpentane in the presence of acid catalysts is described. The composition of the rather complex reaction mixtures is determined by gas-liquid chromatography and mass spectrometry, tert. butylarenes being the main products beside alkylsubstituted indanes and tetralines. Their formation is interpreted as a competition between fragmentation and isomerization of the alkylating agent. By use of trifluoromethanesulfonic acid or combinations of catalysts from HF or HSO₃F with variant metallic fluorides at lower temperatures the selectivity of the reaction may be partially raised.     

Plasma‐Induced Amorphous Shell and Deep Cation‐Site S Doping Endow TiO2 with Extraordinary Sodium Storage Performance

Structural design and modification are effective approaches to regulate the physicochemical properties of TiO₂, which play an important role in achieving advanced materials. Herein, a plasma‐assisted method is reported to synthesize a surface‐defect‐rich and deep‐cation‐site‐rich S doped rutile TiO₂ (R‐TiO_2–x‐S) as an advanced anode for the Na ion battery. An amorphous shell (≈3 nm) is induced by the Ar/H₂ plasma, which brings about the subsequent high S doping concentration (≈4.68 at%) and deep doping depth. Experimental results and density functional theory calculations demonstrate greatly facilitated ion diffusion, improved electronic conductivity, and an increased mobility rate of holes for R‐TiO_2?x‐S, which result in superior rate capability (264.8 and 128.5 mAh g^?1 at 50 and 10 000 mA g^?1, respectively) and excellent cycling stability (almost 100% retention over 6500 cycles). Such improvements signify that plasma treatment offers an innovative and general approach toward designing advanced battery materials.