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Versatile Approach (versatile + approach)
Selected AbstractsPorous Polymer Coatings: a Versatile Approach to Superhydrophobic SurfacesADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Pavel A. Levkin Abstract Here, a facile and inexpensive approach to superhydrophobic polymer coatings is presented. The method involves the in situ polymerization of common monomers in the presence of a porogenic solvent to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The method is applicable to a variety of substrates and is not limited to small areas or flat surfaces. The polymerized material can be ground into a superhydrophobic powder, which, once applied to a surface, renders it superhydrophobic. The morphology of the porous polymer structure can be efficiently controlled by composition of the polymerization mixture, while surface chemistry can be adjusted by photografting. Morphology control is used to reduce the globule size of the porous architecture from micro down to nanoscale thereby affording a transparent material. The influence of both surface chemistry as well as the length scale of surface roughness on the superhydrophobicity is discussed. [source] Gold-Catalyzed Cycloisomerization Reactions of 2-Tosylaminophenylprop-1-yn-3-ols as a Versatile Approach for Indole Synthesis,ANGEWANDTE CHEMIE, Issue 27 2010Prasath Kothandaraman Gold und Indole: Die Titelreaktion verläuft vermutlich über ein Vinyl-Gold-Intermediat, das in,situ durch Einwirkung von AuCl/AgOTf entsteht. Unter den Reaktionsbedingungen werden Inden-anellierte und 2,3-disubstituierte Indolderivate in Ausbeuten bis 94,% erhalten (siehe Schema). [source] An Efficient and Versatile Approach for the Immobilization of Carbene Precursors via Copper-Catalyzed [3 + 2]-Cycloaddition and Their Catalytic Application.CHEMINFORM, Issue 51 2007Kirsten Zeitler Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] A Versatile Approach for the Asymmetric Synthesis of 3-Alkyl-2,3-dihydro-1H-isoindolin-1-ones.CHEMINFORM, Issue 22 2004Ming-De Chen Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Regioselective Nucleophilic Additions to Cross-Conjugated Dienone System Bearing ,-Fluorine: A Versatile Approach to Highly Substituted 2-Cyclopentenones.CHEMINFORM, Issue 45 2001Junji Ichikawa Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Oxidative Inorganic Multilayers for Polypyrrole Film GenerationADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Mikko Salomäki Abstract A controlled nanoscale fabrication of conducting polymer films sets severe requirements for the preparation method and substrate. A new and versatile approach for producing thin polypyrrole films on a variety of surfaces is presented. Purely inorganic thin films are first prepared from poly(metaphosphate) and tetravalent metal ions using a sequential layer-by-layer technique. Redox-active cerium(IV) polyphosphate multilayer and redox-inactive zirconium(IV) and hafnium(IV) polyphosphate multilayers are prepared. Cerium-based polyphosphate films grow exponentially with the number of layers but multilayers containing zirconium or hafnium exhibit a linear buildup process. All the studied systems produce relatively smooth films with initial bilayer thickness less than 2,nm. The cerium(IV) containing film is redox-active, which is shown by its capability to form a polypyrrole layer on its surface by oxidation of pyrrole monomers in the adjacent aqueous solution. This is a general method to produce thin oxidative films of arbitrary size and form on a wide variety of surfaces. [source] Poly(2-(dimethylamino)ethyl methacrylate) Brushes with Incorporated Nanoparticles as a SERS Active Sensing LayerADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Smrati Gupta Abstract A simple, fast, and versatile approach to the fabrication of outstanding surface enhanced Raman spectroscopy (SERS) substrates by exploiting the optical properties of the Ag nanoparticles and functional as well as organizational characteristics of the polymer brushes is reported. First, poly(2-(dimethylamino)ethyl methacrylate) brushes are synthesized directly on glassy carbon by self-initiated photografting and photopolymerization and thoroughly characterized in terms of their thickness, wettability, morphology, and chemical structure by means of ellipsometry, contact angle, AFM, and XPS, respectively. Second, Ag nanoparticles are homogeneously immobilized into the brush layer, resulting in a sensor platform for the detection of organic molecules by SERS. The surface enhancement factor (SEF) as determined by the detection of Rhodamine 6G is calculated as 6,×,106. [source] Swelling-Induced Surface Patterns in Hydrogels with Gradient Crosslinking DensityADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Murat Guvendiren Abstract Hydrogels with controlled surface patterns are useful for a range of applications, including in microdevices, sensors, coatings, and adhesives. In this work, a simple and robust method to generate a wide range of osmotically driven surface patterns, including random, lamellar, peanut, and hexagonal structures is developed. This method does not require the use of organic solvents for swelling, pre-patterning of the film surface, or coating of a second layer on the gel. The patterns are fabricated by exposing a photocurable formulation to light while open to air and then swelling, using oxygen inhibition of the radical polymerization at the surface to create a gradient of crosslinking with depth, which was confirmed by measuring the double bond conversion at the surface, surface mechanics, and molecule diffusion into the network. The modulus gradient, and hence osmotic pressure, is controlled by the crosslinker concentration, and the characteristic size of the patterns is determined by the initial film thickness. The patterns are stable in both swollen and dry states, creating a versatile approach that is useful for diverse polymers to create complex patterns with long-range order. [source] An Approach to Lithographically Defined Self-Assembled Nanoparticle Films,ADVANCED MATERIALS, Issue 7 2006D. Xia Lithographically defined nanoparticle films with high quality and excellent uniformity have been fabricated using a combination of bottom-up self-assembly and top-down interferometic lithography. Using this simple, fast, and versatile approach, various 1D and 2D mesoscopic patterns of silica nanoparticle films are easily fabricated over a large area with nanometer-scale periodicity (see figure). [source] Copper(I)-Catalyzed Asymmetric Addition of Terminal Alkynes to ,-Imino Esters: An Efficient and Direct Method in the Synthesis of Chiral ,3 -Alkynyl ,2,2 -Dimethyl Amino Acid DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Jun Wang Abstract The first catalytic asymmetric addition of terminal alkynes to ,-imino esters was carried out using chiral copper(I) complexes as catalysts under mild reaction conditions, providing an efficient and direct synthetic approach to ,3 -alkynyl ,2,2 -dimethyl amino esters with yields of 73,97% and 48,90% ee. The rich chemistry of the alkynyl functionality makes the present method a powerful and versatile approach to a wide range of optically active ,2,2 -dimethyl amino acid derivatives. [source] A versatile approach for the syntheses of poly(ester amide)s with pendant functional groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2009Katelyn M. Atkins Abstract Poly(ester amide)s (PEAs) are emerging as promising materials for a wide range of biomedical applications due to their potential for both hydrolytic and enzymatic degradation, as well as the ease with which their properties can be tuned by the choice of monomers. The incorporation of pendant functional handles along the PEA backbone has the potential to further expand their applications by allowing the charge and hydrophilicity of the polymers to be altered, and facilitating the conjugation of active molecules such as drugs, targeting groups, and cell signaling molecules. Described here is a simple and versatile strategy based on orthogonal protecting groups, by which L -lysine and L- aspartic acid can be incorporated into several families of PEAs based on monomers including the diacids succinic and terephthalic acid, the diols 1,4-butanediol and 1,8-octanediol, and the amino acids L- alanine and L- phenylalanine. All polymers were thoroughly characterized by nuclear magnetic resonance spectroscopy, infrared spectroscopy, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. It was demonstrated that the side chain protecting groups could be readily removed, allowing the pendant amines or carboxylic acids to be functionalized. In particular, the carboxylic acid groups on a polymer containing L- aspartic acid units were converted to N -hydroxysuccinimidyl esters, providing a useful template for further derivatization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3757,3772, 2009 [source] Photoswitchable architectural polymer: Toward azo-based polyamidoamine side-chain dendritic polyesterJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 23 2001Samaresh Ghosh Abstract A versatile approach to the synthesis of novel polyamidoamine (PAMAM) side-chain dendritic polyester (SCDPE) possessing azobenzene motifs in the polymeric core is described and displayed reversible cis,trans (E/Z) isomerization upon exposure to UV light. A polymerization reaction was conducted in solution using ester-terminated PAMAM dendritic diol (1a, G 3.5) and azobenzene dicarboxylic acid chloride in the presence of triethylamine. PAMAM dendritic diol 1a as well as SCDPE (1) were thoroughly characterized by means of IR and NMR (1H and 13C) spectroscopies. The intrinsic viscosity of 1 at 36 °C in CHCl3 was found to be 0.38 dl/g. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4182,4188, 2001 [source] Nano-Level Mixing of ZnO into Poly(methyl methacrylate)MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 17 2010Mukesh Agrawal Abstract A simple, facile and versatile approach is presented for the preparation of PMMA/ZnO nanocomposite materials, which possess high transparency, no color, good thermal stability, UV absorption and improved mechanical properties. The employed process involved mixing of ZnO nanoparticles dispersed in DMAc with the PMMA matrix dissolved in the same solvent. The effect of ZnO content on the physical properties of the PMMA matrix is studied. A significant improvement in mechanical properties was observed with the incorporation of 0.5 wt.-% ZnO particles. The beauty of the described approach lies in the fact that despite being a simple and facile approach, it offers nano-level (2,5,nm) mixing of ZnO nanoparticles into a polymer matrix. [source] Encapsulation of a Single Metal Nanoparticle with Tunable Size in a Monodisperse Polymer MicrocapsuleMACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2009Haiqing Li Abstract A versatile approach to fabricate monodisperse poly[styrene- co -(divinyl benzene)] (PS- co -DVB) microcapsules that contain a single gold nanoparticle (AuNP) has been demonstrated. Using the PS- co -DVB microcapsule as a microreactor, aqueous HAuCl4 and NaBH4 solutions are subsequently infiltrated. The size of the resulting AuNP inside of the PS- co -DVB microcapsules is easily tunable by controlling the repeated infiltration cycles of aqueous HAuCl4 and NaBH4. PS- co -DVB microcapsules that contain a single silver and palladium nanoparticle are also obtained by following a similar protocol. [source] Preparation and characterization of pore wall-functionalized three-dimensionally ordered macroporous syndiotactic polystyrenePOLYMER ENGINEERING & SCIENCE, Issue 2 2009Xu Zhang A versatile method for the modification of three-dimensionally ordered macroporous (3DOM) highly syndiotactic polystyrene via chloromethylation at the pore walls has been demonstrated. This was followed by reaction with dimethylamine to establish a versatile approach to functionalization of such macroporous polymers. High syndiotacticity of 3DOM sPS is necessary for maintenance of the morphology of the original ordered pore structure after chloromethylation. The relative content of chloromethyl groups was shown to be 1.89 mmol/g3DOM sPS by TG-titration. The functionalized 3DOM sPS was characterized by SEM, FT-IR, and DSC to demonstrate that chloromethylation had occurred at the pore walls and that the dimethylamino moiety had replaced the chlorine atom of the chloromethyl group. DSC examination of the modified polymer indicated that the crystallinity of 3DOM sPS is little affected by functionalization. Thus the excellent properties of sPS are retained by the functionalized material. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers [source] Rational shape engineering of the filamentous protein , prefoldin through incremental gene truncationBIOPOLYMERS, Issue 6 2009Timothy A. Whitehead Abstract An enticing possibility in nanotechnology is to use proteins as templates for the positioning of molecules in regular patterns with nanometer precision over large surface areas. However, the ability to redesign protein quaternary structure to construct new shapes remains underdeveloped. In the present work, we have engineered the dimensions of a filamentous protein, the , prefoldin (, PFD) from the hyperthermophile Methanocaldococcus jannaschii, and have achieved controllable attachment of filaments in a specific orientation on a carbon surface. Four different constructs of , PFD were generated in which the coiled coils extending from the association domain are progressively truncated. Three of the truncation constructs form well-defined filaments with predictable dimensions according to transmission electron microscopy. Two of these constructs had 2D persistence lengths similar to that of , PFD at 300,740 nm. In contrast, the 2D persistence length of the shortest truncation mutant was 3500 nm, indicating that the filament adsorbs along a different axis than the other constructs with its two rows of coiled coils facing out from the surface. The elastic moduli of the filaments range from 0.7,2.1 GPa, similar to rigid plastics and within the lower limit for proteins whose primary intermolecular interaction is hydrogen bonding. These results demonstrate a versatile approach for controlling the overall dimensions and surface orientation of protein filaments, and expand the toolbox by which to tune two overall dimensions in protein space for the creation of templated materials over a wide variety of conditions. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 496,503, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Identification of a ligand for IgG-Fc derived from a soluble peptide library based on fusion proteins secreted by S. cerevisiaeBIOTECHNOLOGY JOURNAL, Issue 6 2007Christa Mersich Abstract Biological libraries are important tools in the development of new peptide-based compounds. Here, we describe the use of a soluble peptide library system as a complementary tool in the field of ligand development. Random peptides were expressed in S. cerevisiae as carboxy-terminal extensions of the eukaryotic initiation factor 5a (eIF5a) and secreted into the culture supernatant. Expression and screening of this library were performed in a microwell format. As an example of this versatile approach, we describe the identification of a ligand for the human IgG-Fc fragment. Ligands binding IgG-Fc show great potential in a wide variety of applications including development of therapeutics, streamlining the large-scale purification of antibodies, and applications in diagnostic tests. We demonstrated the utility of this system. After screening only 6160 clones, we identified a ligand with the peptide sequence of TRRRTCSPPTWPRARARSTPSGCSSTGPSANRG. An affinity constant of 3.9 x 105 M -1 was determined by a biosensor method. Handling and maintenance of this library is conceptually simple and highly applicable for automated high-throughput systems. [source] Multi-tasking with Single Platform Dendrimers for Targeting Sub-Cellular MicroenvironmentsCHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2010Rami Hourani Double trouble! Orthogonally functionalised dendrimers have been constructed by using a versatile approach that is widely applicable for therapeutics and diagnostics by combining imaging agents and therapeutics for synergistic effects. Dendrimers containing a covalently linked dipyrromethene boron difluoride (BODIPY) dye and ,-lipoic acid perform complementary biological functions and target intracellular lipid droplets (see figure). [source] Semiconducting Neutral Microstructures Fabricated by Coordinative Self-Assembly of Intramolecular Charge-Transfer Tetrathiafulvalene DerivativesCHEMISTRY - A EUROPEAN JOURNAL, Issue 20 2009Yan Geng Dr. Abstract A new class of tetrathiafulvalene-based microstructures fabricated by coordinative self-assembly has been prepared by a solution process. Upon incorporation of Pb2+ and Zn2+ ions, 1D wirelike microstructures and spherical polymer particles were achieved, respectively (see picture). The neutral coordination polymers are conductive and magnetic at room temperature without external manipulation. A new class of tetrathiafulvalene(TTF)-based microstructures fabricated by coordinative self-assembly has been successfully prepared by a solution process. The morphology of the TTF coordination polymers is readily tuned by the variation of metal ions. Upon incorporation of Pb2+ and Zn2+ ions, one-dimensional (1D) wirelike microstructures and spherical polymer particles were achieved, respectively. These results indicate that the coordinative approach pursued in this work, in which the building blocks of 1 are linked in a coordination polymer chain by association with metal ions, is an efficient and versatile approach to produce more mechanically robust micro- and nanometer-sized coordination polymer materials. More interestingly, the neutral coordination polymers are conductive and magnetic at room temperature without external manipulation. Such conductivity is reminiscent of the behavior of the neutral conductive TTF in single crystals. [source] Chondrocutaneous advancement flap for reconstruction of helical rim defects in dermatologic surgeryAUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 4 2006Aleksandar L Krunic SUMMARY The helical rim is often affected with cutaneous malignancies and requires special attention in the repair, owing to the complex cartilaginous contour, preservation of the aesthetic contour and restoration of its supportive function for eyeglasses and hearing aids. We review the surgical technique of chondrocutaneous advancement flap described by Antia and Buch as one of the most cosmetically appealing and versatile approaches for the repair of small defects of the ear helix. [source] | |||||||||||||||||||||||||