Injectable Hydrogel for Sustained Protein Release by Salt‐Induced Association of Hyaluronic Acid Nanogel

A hyaluronic acid‐based anionic nanogel formed by self‐assembly of cholesteryl‐group‐bearing HA is designed for protein delivery. The HA nanogel spontaneously binds various types of proteins without denaturation, such as recombinant human growth hormone, erythropoietin, exendin‐4, and lysozyme. The HA nanogel shows unique colloidal properties, in particular that an injectable hydrogel is formed by salt‐induced association of the HA nanogel. A pharmacokinetic study in rats shows that an in situ gel formulation, prepared by simply mixing rhGH and HA nanogel in phosphate buffer, maintains plasma rhGH levels within a narrow range over one week. Therefore, HA nanogels offer a simple method for easy formulation of therapeutic proteins and are effective for sustained protein release systems.

     

White light electroluminescence from graphene‐enhanced single polymer comprising two color emitters of equal molar ratios

White polymeric light‐emitting diode (WPLED) based on a single polymer, poly(3‐hexylthiophene‐alt‐9,9‐dioctylfluorene) (PTAF), has been successfully demonstrated. This conjugated alternating copolymer, PTAF, comprises 50 mol % of 3‐hexylthiophene which is an orange‐red color chromophore and 50 mol % 9,9‐dioctylfluorene which is a bluish‐green color chromophore. It was synthesized by Suzuki cross‐coupling reaction and has a molecular weight of 15,021 and polydispersity of 1.36. Nanocomposite consisting PTAF and graphene nanosheets enhances the optoelectronic properties and the device fabricated with a configuration of ITO/PEDOT:PSS/(PTAF + 1% graphene)/Ca/Al shows two‐color white electroluminescence with CIE 1931 coordinates of (0.28, 0.34). The white luminescence from a single polymer affords the WPLED device a simple structure and low fabrication cost. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

The physical aging phenomenon of 6FDA‐durene polyimide hollow fiber membranes

The aging phenomenon of asymmetric 6FDA‐durene polyimide hollow fibers spun with different shear rates for gas separation has been investigated. The permeances and selectivities of different gases, such as H₂, O₂, N₂, CH_4, and CO₂, were experimentally determined as a function of time for around five months at room temperature. It was found that the gas permeation fluxes of the uncoated and silicone rubber‐coated hollow fibers decreased significantly during the first 30 days following fabrication and then slightly deteriorated thereafter. In the early stage of aging, because of different molecular orientations and skin morphologies induced by shear rates, the percentage of permeance drop for uncoated fibers increased with increasing shear rates, then decreased with increasing shear rates. The permeance of 6FDA‐durene hollow fibers coated with silicone rubber dropped more significantly than the uncoated fibers, implying that silicone rubber coating did affect the aging behavior. This might be due to the fact that silicone rubber layer hindered the molecular relaxation and tightened interface molecules between the dense selective layer and silicone rubber, thus the selectivity increased with aging. Thermal analysis data suggest two processes occurring simultaneously during the aging: one is the relaxation of shear oriented chains, and the other is the densification of chain packing through the reduction of interstitial space among chains. The former has been confirmed by an increase in CTE, while the latter was confirmed by an increase in the peak of β‐relaxation temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 765–775, 2000     

High-pressure combinatorial screening of homogeneous catalysts: hydrogenation of carbon dioxide

A simple method for high-pressure combinatorial catalyst discovery with visual (dye-based) assay is described. With this method, the first highly active catalyst, incorporating metals outside the platinum group, has been identified for CO(2) hydrogenation.     

Synthesis,and Antimycobacterial and Cytotoxic Evaluation of Certain Fluoroquinolone Derivatives

Certain 1‐ethyl‐ and 1‐aryl‐6‐fluoro‐1,4‐dihydroquinol‐4‐one derivatives were synthesized and evaluated for antimycobacterial and cytotoxic activities. Preliminary results indicated that, for 1‐aryl‐6‐fluoroquinolones, both 7‐(piperazin‐1‐yl)‐ and 7‐(4‐methylpiperazin‐1‐yl) derivatives, 9b and 11a , are able to completely inhibit the growth of M. tuberculosis at a concentration of 6.25 μg/ml, while the 7‐[4‐(2‐oxo‐2‐phenylethyl)piperazin‐1‐yl] derivative 13 exhibits only 31% growth inhibition at the same concentration. For 1‐ethyl‐6‐fluoroquinolones, both 7‐[4‐(2‐oxopropyl)piperazin‐1‐yl]‐ and 7‐[4‐(2‐oxo‐2‐phenylethyl)piperazin‐1‐yl]‐derivatives, 2a and 2b , respectively, show complete inhibition, while their 2‐iminoethyl and substituted phenyl counterparts 3a and 2c are less active. In addition, the 6,8‐difluoro derivative was a more‐favorable inhibitor than its 6‐fluoro counterpart ( 2b vs. 2d ). These results deserve full attention especially because 2a, 2b, 9b , and 11a are non‐cytotoxic at a concentration of 100 μM . Furthermore, compound 9b proved to be a potent anti‐TB agent with selective index (SI)>40 and an EC₉₀ value of 5.75 μg/ml.     

(C2H10N2)[BPO4F2] — Structural Relations between [BPO4F2]2— and [Si2O6]4—

(C₂H₁₀N₂)[BPO₄F₂] — Strukturbeziehungen zwischen [BPO₄F₂]^2— und [Si₂O₆]^4— Colourless crystals of (C₂H₁₀N₂)[BPO₄F₂] were prepared from mixture of ethylendiamine, H₃BO₃, BF₃ · C₂H₅NH₂, H₃PO₄ and HCl under mild hydrothermal conditions (220 °C). The crystal structure was determined by single crystal methods (triclinic, P1¯ (no. 2), a = 451.85(5) pm, b = 710.20(8) pm, c = 1210.2(2) pm, α = 86.08(1)°, β = 88.52(2)°, γ = 71.74(1)°, Z = 2) and contains infinite tetrahedral zweier‐single‐chains {[BPO₄F₂]^2—} which are isoelectronic (48e^—) with the polyanions {[Si₂O₆]^4—} of the pyroxene family.     

Fabrication and evaluation of bacterial cellulose-polyaniline composites by interfacial polymerization

The fabrication and evaluation of nanocomposites based on microbial cellulose and polyaniline (PANi) are described. Microbial cellulose, so called, bacterial cellulose (BC) was introduced to interfacial polymerization of aniline. Two different phases based on water and chloroform made it easy for nanosized PANi particles to be synthesized on BC. Without any help of a surfactant or templates, BC played a critical role of supporting the growth of PANi. As a function of aniline concentration, the corresponding PANi content and volume resistivity were checked. From morphological images observed by FE-SEM, PANi nanoparticles were densely arrayed along every fiber of BC. The conjugated backbone of PANi was thought to contribute to the improvements of thermal stability of PANi/BC composites. The stiffness and brittleness of PANi were compensated by more ductile BC, suggesting BC can be a promising substrate for it. By the simple and facile interfacial polymerization, the electrical conductivity of PANi/BC composites reached up to 3.8?×?10^?1?S/cm when 0.32?M of aniline was used. This PANi/BC nanocomposite can be useful in applications requiring biocompatibility and electrical conductivity such as biological and chemical sensors.     

Synthesis and Characterization of Chiral Binuclear Organolanthanide and Yttrium Alkoxides Containing Cyclopentadienyl Ligand

Recently,variousdimericlanthanidealkoxidesofthetype[(Ln(p-oR)(Cp)2}2]havebeenpreparedbytreatmentofthechlorocomplexeswithsodiumalkoxideslorprotonationofLn(Cp)3withstoichiometricamountsofalcohols2.Butthechiralorganolanthanidepolymericalkoxidescontainingcyclopentadienylgroupsandopticallypurediolligandshavenotbeenreporteduptonow3.Furthermore,themethodofprotonationisusuallyappliedinnon-coordinatingsolventssuchasheptane,hexane,benzeneandtoluene.Inthispaper,wewishtoreportthefirstsynthesisofchiralcy…     

含吡啶环系西佛碱大环配合物和氮杂大环自由配体的合成

2,6-二羟甲基吡啶(1)经活性MnO_2氧化得到2,6-二甲酰基吡啶(2)。邻硝基苯酚与N-取代的二(氯乙基)胺在DMF溶液中反应,得到N-取代的1,5-二(邻硝基苯氧基)-3-氮杂戊烷(3a～3c),再经水合肼/Raney Ni还原,获得N-取代的1,5-二(邻氨基苯氧基)-3-氮杂戊烷(4a～4c)。利用Ba~(2 )作为模板离子,(2)分别与(4a～4c)反应,合成了一类新的含吡啶环系西佛碱大环配合物Ⅰ～Ⅲ,配合物Ⅰ、Ⅲ经与NaBH_4的乙醇溶液还原解络,得到氮杂大环自由配体Ⅳ和Ⅴ。所有西佛碱大环配合物和氮杂大环自由配体均经元素分析、IR、~1H NMR、MS等证实了它们的结构和组成。     

含氰基侧基聚芳醚砜的合成与表征

汉２，６－二卤苯甲腈、４，４′－二氯二苯砜、４，４′－二羟基二苯砜、间苯二酚、对苯二酚、酚酞及双酚Ａ为主要原料，合成了含不同结构单元和不同氰基含量的含氰基侧基的聚芳醚砜，并采用ＩＲ、＾１３ＣＮＭＲ等分析手段对其结构进行了表征，同时研究了结构单元和氰基含量对聚芳醚砜性能的影响。