bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dipeptide and Tripeptide Conjugates as Low‐Molecular‐Weight Hydrogelators
Authors: Adams Dave J. 
Published: November 2010

AbstractDipeptide and tripeptide conjugates are receiving significant current interest as LMWG, driven by the accessibility of these materials, their relatively low cost and also the large number of examples that successfully form hydrogels. Their behaviour can easily modified by changes in the amino acids or the aromatic end groups chosen. The assembly process has been relatively well described for a small subset of these gelators, giving a good idea of the behaviour of these molecules and allowing an understanding of the conditions under which assembly will occur. Here, we critically review the literature in this area and consider the importance of gelator choice and method of assembly on the outcome of the gelation. We also discuss the applications of these hydrogels. magnified image
Coating of Titanium Implant Materials with Thin Polymeric Films for Binding the Signaling Protein BMP2
Authors: Lorenz Corinna , Hoffmann Andrea , Gross Gerhard , Windhagen Henning , Dellinger Philip , Möhwald Kai , Dempwolf Wibke , Menzel Henning 
Published: November 2010

AbstractA fast and simple approach for immobilization using copolymers as interlayers is reported. The synthesized copolymers form stable self‐assembled layers on implant materials like, e.g., titanium in a simple coating/drying/washing sequence and have functional groups which can bind proteins from an aqueous solution. The copolymer films have been characterized via ellipsometry and contact angle measurements and were tested for biocompatibility. An immunoassay was used to determine the amount of BMP2 and demonstrated an approximately 10‐fold increase as compared to previously used self‐assembled monolayers.1 A BMP2‐responsive cell line with luciferase detection was used to determine the biological activity of the bound signaling protein. magnified image
Di‐ and Triblock siRNA‐PEG Copolymers: PEG Density Effect of Polyelectrolyte Complexes on Cellular Uptake and Gene Silencing Efficiency
Authors: Lee Soo Hyeon , Mok Hyejung , Park Tae Gwan 
Published: November 2010

AbstractDi‐ and triblock siRNA/PEG copolymers were synthesized and complexed with cationic SLN for assessing their gene silencing efficiency as a function of PEG density. A sssiRNA and a sassiRNA were separately conjugated with PEG via a disulfide linkage. AB‐type diblock and ABA‐type triblock copolymers were successfully prepared by stoichiometric hybridization of sssiRNA‐PEG conjugate with sassiRNA and sassiRNA‐PEG conjugate, respectively. The resultant di‐ and triblock copolymers were characterized by means of GPC and gel electrophoresis. The serum stability of siRNA in the copolymers was enhanced as compared to that of naked siRNA. Using cationic SLN as a model carrier, the PEGylation density effect of the siRNA‐PEG/SLN complexes on gene silencing and cellular uptake was analyzed. magnified image
Electrospun Nanofibrous Polycaprolactone Scaffolds for Tissue Engineering of Annulus Fibrosus
Authors: Koepsell Laura , Zhang Lifeng , Neufeld Daniel , Fong Hao , Deng Ying 
Published: November 2010

AbstractThe annulus fibrosus comprises concentric lamellae that can be damaged due to intervertebral disc degeneration; to provide permanent repair of these acquired structural defects, one solution is to fabricate scaffolds that are designed to support the growth of annulus fibrosus cells. In this study, electrospun nanofibrous scaffolds of polycaprolactone are fabricated in random, aligned, and round‐end configurations. Primary porcine annulus fibrosus cells are grown on the scaffolds and evaluated for attachment, proliferation, and production of extracellular matrix. The scaffold consisting of round‐end nanofibers substantially outperforms the random and aligned scaffolds on cell adhesion; additionally, the scaffold with aligned nanofibers strongly affects the orientation of cells. magnified image
A Liquid‐Crystalline Co‐Polysiloxane with Asymmetric Bent Side Chains
Authors: Bubnov Alexej , Novotná Vladimíra , Pociecha Damian , Kašpar Miroslav , Hamplová Vĕra , Galli Giancarlo , Glogarová Milada 
Published: November 2010

AbstractA co‐polysiloxane has been prepared with an asymmetric bent side group based on a liquid‐crystalline monomer showing a B2 (SmCP) phase. In order to dilute the side chain mesogens along the polymer backbone, octyl side chains were also incorporated. X‐ray studies confirmed that the resulting co‐polysiloxane exhibits a liquid‐crystalline layered phase, the siloxane polymer chains being microphase segregated from the incompatible side chain mesogens. The mesophase of polymer exhibits a homeotropic structure that can be successfully aligned by unidirectional shear. This phase does not exhibit polar switching under an applied electric field unlike the bent‐core monomer used as the side chains of this polymer. This can be caused by the homeotropic alignment of the polymer samples. magnified image
Polyterthiophenes Incorporating 3,4‐Difluorothiophene Units: Application in Organic Field‐Effect Transistors
Authors: Crouch David J. , Sparrowe David , Heeney Martin , McCulloch Iain , Skabara Peter J. 
Published: November 2010

AbstractTwo terthiophenes bearing core fluorinated thienyl units have been synthesised as potential semiconductor materials for organic field‐effect transistors. Polymerisation of these compounds has been achieved using conventional iron(III) chloride oxidative coupling methods and by electrochemical oxidation. Characterisation of the fluorinated materials has been achieved by absorption spectroscopy and cyclic voltammetry. A soluble hexyl‐functionalised polymer (poly8b) was used in an OFET device; hole mobilities were measured up to 3 × 10−3 cm2 · V−1 · s−1, and the device had an on/off ratio of 105 and a turn‐on voltage of +4 V. magnified image
Polyethylene/Clay Nanocomposites Made with Metallocenes Supported on Different Organoclays
Authors: Maneshi Abolfazl , Soares João B.P. , Simon Leonardo C. 
Published: November 2010

AbstractThe success of in situ polymerizations, measured by means of high polymerization activity, uniform exfoliation and clay dispersion in the polymer matrix, and good powder morphology, depends on how well the catalyst is supported onto the clay surface. A novel catalyst supporting method that does not require the addition of methylaluminoxane was applied to different organically modified clays and sodium montmorillonite. The supported catalysts were used to polymerize ethylene. We found out that only the clay modified with tertiary ammonium salts was an effective support for ethylene polymerization, generating a supported catalyst that has high polymerization activity, and produces nanocomposites with good powder morphology and excellent clay exfoliation. magnified image
Disulfide‐Containing Hyperbranched Polyethylenimine Derivatives via Click Chemistry for Nonviral Gene Delivery
Authors: Jiang Xulin , Liu Jia , Xu Li , Zhuo Renxi 
Published: November 2010

AbstractReducible disulfide‐containing hyperbranched PEI‐SS‐HP was synthesized via click chemistry and evaluated as nonviral gene carrier. The structure of the polymers was confirmed by 1H NMR and FTIR. It was shown that the PEI‐SS‐HP was able to bind plasmid DNA to positively charged nanoparticles. The reduction sensitivity of the PEI‐SS‐HP was confirmed by gel retardation assay in the presence of DTT mimicking an intracellular reductive environment. In vitro experiments revealed that the reducible PEI‐SS‐HP not only had much lower cytotoxicity, but also posed superior transfection activity as compared to non‐degradable 25‐kDa PEI. The results indicate that a reducibly degradable PEI‐SS‐HP can be a promising gene vector. magnified image
Luminescent Sensory Polymer Coating Composed of Platinumporphyrin and Poly(trimethylsilylpropyne) for Real‐Time Oxygen Visualization in Operating PEFCs
Authors: Hyakutake Tsuyoshi , Ishigami Yuta , Kato Junji , Inukai Junji , Miyatake Kenji , Nishide Hiroyuki , Watanabe Masahiro 
Published: November 2010

AbstractA luminescent PtTFP/PMSP polymer coating was prepared for the oxygen partial pressure visualization inside a PEFC. PMSP formed a smooth and tough coating as a highly oxygen‐permeable matrix with a thickness of ca. 2 µm in which the PtTFP was homogeneously dispersed. The coating displayed a strong red luminescence with significantly decreasing intensity upon increasing oxygen partial pressure. The sensitivity for the oxygen partial pressure was high and the analytical curve of the sensor polymer coating was undisturbed by external factors. The PtTFP/PMSP sensor was coated on the surface of a cathode gas diffusion layer on the air flow channel inside PEFC. The oxygen‐pressure distribution in the air flow channel was successfully visualized while operating the PEFC. magnified image
Structure and Behavior of Polydiacetylene‐Based Micelles
Authors: Perino Aurélia , Klymchenko Andrey , Morere Alexandre , Contal Emmanuel , Rameau Alain , Guenet Jean‐Michel , Mély Yves , Wagner Alain 
Published: November 2010

AbstractThe effect of photopolymerization on the structure, stability and encapsulation properties of polydiacetylene micelles containing nitrilotriacetic acid head groups are investigated. Micellar nanostructures of 7–10 nm diameter are identified that are invariant after polymerization. In the micelles, the polymerized ene‐yne chains are much shorter than in planar lipid membranes. SANS confirmed the presence of a monodisperse population of small particles before and after polymerization. It is shown that the CMC decreases manifold after micelle photopolymerization, indicating that it stabilizes the micellar structure. After photopolymerization, these micelles preserved their strong ability to solubilize a hydrophobic pigment, which makes them potentially interesting as drug delivery vehicles.
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Design of Patterned Surfaces with Selective Wetting Using Nanoimprint Lithography
Authors: Bessonov Aleksander , Kim Jeong‐Gil , Seo Jung‐Woo , Lee Jong‐Woo , Lee Sukwon 
Published: November 2010

AbstractThe fabrication of flexible surfaces with a combination of ultrahydrophobic and hydrophilic properties at alternating locations by UV NIL is reported. A new method for master fabrication based on nanoimprinting combined with photolithography is described. The master is used for a double replica technique to imprint nanopillars atop microstripes on a plastic substrate. Selective wetting is achieved due to ultrahydrophobic nanopatterned regions with 126° WCA and hydrophilic flat regions with 70° WCA on a single surface. By covering surface with hydrophobic SAM, a static contact angle of nanopillars is increased up to 163° indicating superhydrophobicity. We also show that the Cassie‐Wenzel theory successfully predicts the experimental apparent contact angles. magnified image
Enzymatic Synthesis and Chemical Recycling of Polythiocaprolactone
Authors: Shimokawa Keisuke , Kato Makoto , Matsumura Shuichi 
Published: November 2010

AbstractHigh‐molecular‐weight polythiocaprolactone (PTCL) was prepared in a green process via lipase‐catalyzed ROP of a cyclic 6‐mercaptohexanoic acid (6MH) oligomer. PTCL was readily depolymerized by lipase to cyclic 6MH in dilute toluene solution, which was then readily repolymerized by the same lipase to produce PTCL with the same $\overline {M} _{{\rm w}} $ as the initial PTCL in a chemical recycling process. The Tm of PTCL was higher than that of the corresponding PCL. A P(TCL‐co‐CL) copolymer with 60 mol‐% TCL (6MH) units showed a higher Tm as the PCL homopolymer. Similar apparent Km values were obtained for the cyclic 6MH oligomers and caprolactone oligomers, however, the Vmax of cyclic 6MH oligomers was significantly lower than that of the corresponding caprolactone oligomers. magnified image
Synthesis and Photovoltaic Properties of Donor–Acceptor Copolymer Based on Dithienopyrrole and Thienopyrroledione
Authors: Zhou Erjun , Cong Junzi , Tajima Keisuke , Yang Chunhe , Hashimoto Kazuhito 
Published: November 2010

AbstractA novel donor–acceptor (D–A) type alternating copolymer based on dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) and thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) was synthesized. The polymer has a broad absorption spectrum in the range of 350–810 nm. The energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the copolymer were −5.11 and −3.63 eV, respectively, as determined by cyclic voltammetry. Bulk heterojunction type polymer solar cells based on PDTP‐TPD and PC70BM, showed power conversion efficiency (PCE) up to 1.6% with an open‐circuit voltage of VOC = 0.66 V, a short‐circuit current of ISC = 4.98 mA · cm−2, and a fill factor of FF = 0.50. The VOC of 0.66 V is the highest value among DTP‐based photovoltaic polymers. magnified image
Solid‐State Polymerization of Poly(ethylene terephthalate): The Effect of Water Vapor in the Carrier Gas
Authors: Filgueiras Viviane , Vouyiouka Stamatina N. , Papaspyrides Constantine D. , Lima Enrique L. , Pinto Jose Carlos 
Published: November 2010

AbstractSSP of PET has been thoroughly investigated under the regimes of chemical reaction and particle diffusion control. However, the majority of industrial PET plants operate under conditions of surface by‐product diffusion control, mainly due to recycling cycles of the carrier gas. The presence of residual volatile by‐products in the carrier gas (especially water) may affect adversely the polymerization reaction and the resulting polymer quality. For this reason, the effects caused by varying water vapor content of the carrier gas on the course of the PET SSP are analyzed, with emphasis on the intrinsic viscosity. The presence of small amounts of water in the carrier gas is found to exert a pronounced effect on the course of polymerization, leading to significant reduction of the molar masses of the final product.
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Amine‐Reactive PEGylated Nanoparticles for Potential Bioconjugation
Authors: Delaittre Guillaume , Justribó‐Hernández Gemma , Nolte Roeland J. M. , Cornelissen Jeroen J. L. M. 
Published: November 2010

AbstractWater‐dispersible PEGylated nanoparticles (NPs) presenting amine‐reactive conjugation sites at their surfaces were synthesized and their ability to react with amines was demonstrated. An amphiphilic block copolymer bearing an N‐succinimidyl ester at its water‐soluble end was synthesized by the consecutive controlled radical polymerization of poly(ethylene glycol) methacrylate and styrene from a functional halide initiator. After purification of the copolymer, NPs of approximately 40 nm were obtained by a self‐assembly process in water. The reactivity of the NPs was evidenced by reacting them with primary amines, including a fluorescent dye. The activated ester remained stable throughout all synthetic steps and a nearly quantitative coupling efficiency was obtained.
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Kinetic Control of Monomer Sequence Distribution in Living Anionic Copolymerisation
Authors: Natalello Adrian , Hall John N. , Eccles E. Alex L. , Kimani Solomon M. , Hutchings Lian R. 
Published: November 2010

AbstractSequence control in synthetic polymers is a subject that is sparsely reported with little research in the field of sequence control in chain growth polymerisation. We report herein preliminary investigations into anionic copolymerisation of diphenylethylene (DPE) and its derivatives with styrene. DPE is a monomer that will only copolymerise and can form alternating copolymers. However, by introducing electron donating or withdrawing substituents onto the phenyl rings of DPE it is possible to prepare new range of (alternating) copolymers and with careful choice of monomer combination and conditions, the kinetically controlled (simultaneous) copolymerisation of three or more monomers results in copolymers with a greater degree of monomer sequence control.
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De Novo Design of Supercharged, Unfolded Protein Polymers, and Their Assembly into Supramolecular Aggregates
Authors: Kolbe Anke , del Mercato Loretta L. , Abbasi Azhar Z. , Rivera Gil Pilar , Gorzini Sekineh J. , Huibers Wim H. C. , Poolman Bert , Parak Wolfgang J. , Herrmann Andreas 
Published: November 2010

AbstractHere we report for the first time the design and expression of highly charged, unfolded protein polymers based on elastin‐like peptides (ELPs). Positively and negatively charged variants were achieved by introducing lysine and glutamic acid residues, respectively, within the repetitive pentapeptide units. Subsequently it was demonstrated that the monodisperse protein polyelectrolytes with precisely defined amino acid compositions, sequences, and stereochemistries can be transferred into superstructures exploiting their electrostatic interactions. Hollow capsules were assembled from oppositely charged protein chains by using the layer‐by‐layer technique. The structures of the capsules were analyzed by various microscopy techniques revealing the fabrication of multilayer containers. Due to their low toxicity in comparison to other polyelectrolytes, supercharged ELPs are appealing candidates for the construction of electrostatically induced scaffolds in biomedicine. magnified image
Designer Template Initiator for Sequence Regulated Polymerization: Systems Design for Substrate‐Selective Metal‐Catalyzed Radical Addition and Living Radical Polymerization
Authors: Ida Shohei , Ouchi Makoto , Sawamoto Mitsuo 
Published: November 2010

Abstract“Template initiator”' platforms (1) have been designed for expressing the sequence information in a template in radical polymerization. Thus, we demonstrated the structural adequacy of 1 consisting of two initiating sites placed ortho to each other in benzene: one for living cationic polymerization to introduce a template carrying substrate‐recognition tags, and the other for metal‐catalyzed living radical polymerization to achieve sequence regulation. For example, for two positional isomers with an amine template for an acid monomer, only the ortho initiator induced selective radical addition of MAA (recognizable) over MMA (non‐recognizable). Another version was an oligo(vinyl ether) with a multiple amine template, which demonstrated template effects for MAA recognition over BzMA in copolymerization.
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Toroidal Nanostructures from Self‐Assembly of Block Copolypeptides Based on Poly(L‐Arginine) and β‐Sheet Peptide
Authors: Lim Yong‐beom , Lee Eunji , Lee Myongsoo 
Published: November 2010

AbstractWe demonstrate here that rationally designed block copolypeptides based on poly(L‐arginine) and β‐sheet peptides can form toroidal nanostructures. In aqueous solution, we found that 1D nanoribbons roll up and connect in an end‐to‐end fashion under charge‐balanced conditions, resulting in the formation of barrel‐like toroidal nanostructures. Toroidal diameter was highly uniform (10 nm), indicating that there is a preferred geometrical packing requirement for toroid formation. Our results demonstrate that, when suitably designed, β‐sheet nanostructures can be manipulated to form more complex 2D nanostructures. This finding offers new opportunities not only for the fabrication of more sophisticated peptide‐based nanobiomaterials, but also for understanding and inhibiting protein misfolding diseases. magnified image
Mathematical Modeling of the Microstructure of Poly(propylene) Made with Ziegler‐Natta Catalysts in the Presence of Electron Donors
Authors: Alshaiban Ahmad , Soares João B. P. 
Published: November 2010

AbstractTwo different modeling techniques, the method of moments and Monte Carlo simulation, were compared for propylene polymerization with coordination catalysts including a new mechanistic step, site transformation by electron donors. We used the models to show how the molecular weight and tacticity distributions of several poly(propylene) chain populations were affected by changing the concentration of hydrogen, electron donor, and propylene in the reactor, under steady‐state or dynamic operating conditions. The Monte Carlo simulation describes the molecular weight and tacticity distributions for the whole polymer and chain populations with distinct microstructural characteristics. We have also applied the Monte Carlo model to simulate the pentad sequence distributions and its equivalent 13C NMR spectra. magnified image
Proceedings of the eighth annual conference of the British Association for biological anthropology and osteoarchaeology bar is 1743 Megan Brickley & Shannon Dixon Smith (eds). British Archaeological Reports (BAR), John and Erica Hedges Ltd., Oxford, UK, 2008. 120 pp, ISBN 978‐1407‐3018‐53, (paperback).
Authors: Cunha Eugénia 
Published: November 2010

AbstractNoAbstract
Guideline‐conformity of initiation with oral hypoglycemic treatment for patients with newly therapy‐dependent type 2 diabetes mellitus in Austria
Authors: Winkelmayer Wolfgang C. , Stedman Margaret R. , Pogantsch Michaela , Wieninger Peter , Bucsics Anna , Asslaber Markus , Bauer Rosemarie , Burkhardt Thomas , Schautzer Alexandra , Brookhart M. Alan ,   for the Pharmacoeconomics Advisory Council of the Main Association of Austrian Sickness Funds
Published: November 2010

AbstractPurposeTo determine guideline conformity of initiation of oral hypoglycemic (OH) treatment for type 2 diabetes in Austria; to study patient and prescriber correlates of recommended initiation with metformin monotherapy.MethodsWe used claims from 11 sickness funds that covered 7.5 million individuals, representing >90% of the Austrian population. First‐time OH use was defined as a first filled prescription after one year without any OH drug or insulin. Among these incident users, we described the OH drug class used and defined correlates of initiation with metformin monotherapy.ResultsFrom 1/2007 to 6/2008, we identified 42 882 incident users of an OH drug: 70.8% used metformin, 24.7% used a sulfonylurea, and 4.5% initiated treatment with another class. We estimated the incidence of OH‐dependent type 2 diabetes at 3.8–4.4 per 1000 patient‐years. We conducted multivariate analyses among 39 077 patients with available prescriber information. Independent correlates of initiation with metformin were younger age, female gender, waived co‐payment, more recent initiation, fewer hospital days and more therapeutic classes received in the year prior to first OH therapy (all p < 0.001). Prescriber specialty and age (p < 0.001), but not gender, were also associated with metformin initiation. Approximately 20% of metformin initiators had a second OH drug added within <18 months. While we were unable to ascertain specific contraindications to metformin (renal insufficiency, hepatic failure), <10% of the general population are expected to have these conditions.ConclusionsSeventy per cent of new initiators of OH treatment in Austria received metformin as recommended by international guidelines. At least 20% did not, taking into account possible contraindications, which provides an opportunity for intervention. Copyright © 2010 John Wiley & Sons, Ltd.