bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of ABC and CABAC Triphilic Block Copolymers by ATRP Combined with ‘Click’ Chemistry
Authors: Kyeremateng Samuel Oppong , Amado Elkin , Blume Alfred , Kressler Jörg 
Published: May 2008

AbstractATRP using poly(propylene oxide) monofunctional macroinitiator was carried out with solketal methacrylate (SMA) and the non‐reactive PPO having two N3 terminal groups was removed by dissolution in an excess of n‐hexane. The resulting azido terminated AB diblock copolymer was ‘clicked’ with an α‐alkyne fluorinated compound, followed by acid hydrolysis of the SMA units, a triphilic ABC triblock copolymer was prepared. ATRP of SMA with a difunctional PPO macroinitiator to give ABA triblock copolymer was also carried out. The terminal Br was again exchanged with N3, ‘clicked’ with the α‐alkyne fluorinated compound and likewise hydrolyzed to give a triphilic CABAC pentablock copolymer, i.e., hydrophilic, oleophilic, and fluorophilic blocks were combined.magnified image
Shrinking Behavior of Surfactant‐Grafted Thermosensitive Gels and the Mechanism of Rapid Shrinking
Authors: Okeyoshi Kosuke , Abe Tetsuya , Noguchi Yuji , Furukawa Hidemitsu , Yoshida Ryo 
Published: May 2008

AbstractSurfactant‐grafted hydrogels with a fast response to temperature were prepared. In order to clarify the mechanism of rapid shrinking, the effects of the grafted surfactant and the homogeneity of the main chain were investigated. Poly(NIPAAm‐co‐S180A) gels prepared using a chemical cross‐linker (bis‐PNS gels) exhibited rapid shrinking, as did PNS gels prepared by γ‐ray irradiation (γ‐PNS gels). This suggested that the rapid shrinking of the PNS gel did not depend on the homogeneity of the main‐chain structure. The shrinking kinetics of the bis‐PNS gels depended on the amount of the introduced surfactant, which means that shrinking is enhanced by micelle formation as a dynamic driving force. From the analysis by dynamic light scattering (DLS) and scanning microscopic light scattering (SMILS), it was suggested that the micelle structure, which induced rapid shrinking, existed in the bis‐PNS gel.magnified image
Tuning Surface Wettability of Poly(3‐sulfopropyl methacrylate) Brushes by Cationic Surfactant‐Driven Interactions
Authors: Döbbelin Markus , Arias Garciela , Loinaz Iraida , Llarena Irantzu , Mecerreyes David , Moya Sergio 
Published: May 2008

AbstractIn this communication, polyanionic poly(potassium 3‐sulfopropyl methacrylate) (PSPM) brushes were switched from hydrophilic to hydrophobic by exchange of the counter cations. First, poly(potassium 3‐sulfopropyl methacrylate) brushes were grown by means of atom transfer radical polymerization (ATRP) from thiol monolayers of initiating ω‐mercaptoundecyl bromoisobutyrate and mixed monolayers of thiol initiator and 1‐undecanothiol (blank thiol) attached to gold surfaces. The kinetics of the polymerization reaction were followed by means of the quartz microbalance technique with dissipation (QCM‐D). The collapse of PSPM brushes in the presence of cationic surfactants like quaternary ammonium salts (tetraethylammonium bromide, hexadecyltrimethylammonium bromide) and imidazolium salts (1‐dodecyl‐3‐methylimidazolium bromide, 1H,1H,2H,2H‐perfluoro‐1‐decyl‐3‐methylimidazolium bromide) was shown by QCM‐D. Water contact angle measurements proved that the wettability of the surface could be tuned reversibly from hydrophilic values (<30 °) to hydrophobic ones (>85 °).magnified image
Design of a Linear Poly(3‐hexylthiophene)/Fullerene‐Based Donor‐Acceptor Rod‐Coil Block Copolymer
Authors: Richard Fanny , Brochon Cyril , Leclerc Nicolas , Eckhardt Doreen , Heiser Thomas , Hadziioannou Georges 
Published: May 2008

AbstractNovel fullerene‐grafted poly(3‐hexylthiophene) (P3HT)‐based rod‐coil block copolymers have been synthesized. The regioregular P3HT rod block has been synthesized by a modified Grignard metathesis reaction (GRIM). An original in situ end‐capping reaction has been developed in order to convert the P3HT block into an efficient macro‐initiator for the nitroxide‐mediated radical polymerization (NMRP) of the coil block. Controlled radical polymerization of the second poly(butylacrylate‐stat‐chloromethylstyrene) [P(BA‐stat‐CMS)] block has been done through various conditions leading to different coil block lengths. The final electron donor‐acceptor block copolymer has been obtained after C60 grafting in soft conditions. Copolymers have been characterized by 1H NMR and size exclusion chromatography. Optical characterizations, before and after C60 grafting, are reported.magnified image
Matrix Representation of Polymer Chain Size Distributions, 3 – Case Studies for Linear Polymerization Mechanisms at Transient Conditions
Authors: Sanches Heloísa L. , Melo Príamo A. , Pinto José Carlos 
Published: May 2008

AbstractThe mass balance equations used to describe different polymerization systems are represented and analyzed with the help of a general matrix framework previously developed. Some of its properties were presented in previous works and are illustrated here in three examples. The first example regards the dynamics of a copolymerization reactor. It is shown that terminal and penultimate models may predict qualitatively different responses in batch reactions. The second example also regards the dynamics of copolymerization reactions. It is shown how manipulation of initial conditions and monomer feed rates can be used to keep copolymer composition constant throughout the batch. The third example concerns the existence of oscillating chain size distributions when there are multiple monomer insertion steps.magnified image
Membrane‐tethered proteins for basic research, imaging, and therapy
Authors: Cheng Tian‐Lu , Roffler Steve 
Published: May 2008

AbstractSecreted and intracellular proteins including antibodies, cytokines, major histocompatibility complex molecules, antigens, and enzymes can be redirected to and anchored on the surface of mammalian cells to reveal novel functions and properties such as reducing systemic toxicity, altering the in vivo distribution of drugs and extending the range of useful drugs, creating novel, specific signaling receptors and reshaping protein immunogenicity. The present review highlights progress in designing vectors to target and retain chimeric proteins on the surface of mammalian cells. Comparison of chimeric proteins indicates that selection of the proper cytoplasmic domain and introduction of oligiosaccharides near the cell surface can dramatically enhance surface expression, especially for single‐chain antibodies. We also describe progress and limitations of employing surface‐tethered proteins for preferential activation of prodrugs at cancer cells, imaging gene expression in living animals, performing high‐throughput screening, selectively activating immune cells in tumors, producing new adhesion molecules, creating local immune privileged sites, limiting the distribution of soluble factors such as cytokines, and enhancing polypeptide immunogenicity. Surface‐anchored chimeric proteins represent a rich source for developing new techniques and creating novel therapeutics. © 2008 Wiley Periodicals, Inc. Med Res Rev, 28, No. 6, 885–928, 2008
Regularity of preventive foot care in persons with diabetes: Results from the Nord‐Trøndelag Health Study
Authors: Iversen Marjolein M. , Østbye Truls , Clipp Elizabeth , Midthjell Kristian , Uhlving Sverre , Graue Marit , Hanestad Berit R. 
Published: May 2008

AbstractThe purpose of the present study was to examine the regularity of preventive care for persons with diabetes in the Nord‐Trøndelag Health Study to identify associated demographic, lifestyle, and disease‐related factors. Among 1,972 persons with diabetes, 1,459 (74%) answered questions related to preventive foot care. The final sample included 1,312 persons with known diabetes, but without a self‐reported history of foot ulcer. Almost 85% reported receiving regular clinical diabetes examinations, 31.7% reported regular foot inspection by health care personnel, and 66.3% reported foot self‐inspection. Only 58.8% reported regular clinical diabetes examination combined with foot inspection. Males, patients not using insulin, and those with shorter diabetes duration or macrovascular complications were more likely to report less regular preventive care. © 2008 Wiley Periodicals, Inc. Res Nurs Health 31:226–237, 2008
Synthesis, characterization, and evaluation of enzymatically degradable poly(N‐isopropylacrylamide‐co‐acrylic acid) hydrogels for colon‐specific drug delivery
Authors: Li Shengfang , Liu Xianli 
Published: May 2008

AbstractThe enzymatically degradable poly(N‐isopropylacrylamide‐co‐acrylic acid) hydrogels were prepared using 4,4′‐bis(methacryloylamino)azobenzene (BMAAB) as the crosslinker. It was found that the incorporated N‐isopropylacrylamide (NIPAAm) monomer did not change the enzymatic degradation of hydrogel, but remarkably enhanced the loading of protein drug. The hydrogels exhibited a phase transition temperature between 4°C (refrigerator temperature) and 37°C (human body temperature). Bovine serum albumin (BSA) as a model drug was loaded into the hydrogels by soaking the gels in a pH 7.4 buffer solution at 4°C, where the hydrogel was in a swollen status. The high swelling of hydrogels at 4°C enhanced the loading of BSA (loading capability, ca. 144.5 mg BSA/g gel). The drug was released gradually in the pH 7.4 buffer solution at 37°C, where the hydrogel was in a shrunken state. In contrast, the enzymatic degradation of hydrogels resulted in complete release of BSA in pH 7.4 buffer solution containing the cecal suspension at 37°C (cumulative release: ca. 100 mg BSA/g gel after 4 days). Copyright © 2008 John Wiley & Sons, Ltd.
Electrochemical polymerization of imidazolum‐ionic liquids bearing a pyrrole moiety
Authors: Zhang Weixia , Li Yan , Lin Changxu , An Qi , Tao Chengan , Gao Yongbing , Li Guangtao 
Published: May 2008

AbstractA series of imidazolium‐based ionic liquid monomers bearing a terminal pyrrole moiety were synthesized and electrochemically polymerized. It is found that the polymerizability of the synthesized ionic liquids is strongly dependent on the type of the counteranions. Although bromide monomer is not polymerizable, well‐defined polymeric films can be formed on various substrates in the cases of flour‐containing anions (BF4−, PF6−). The performed characterizations show that all resulting polypyrrole films are electroactive, and the imidazolium‐based ionic liquid moieties are correctly incorporated in polymer films during the electropolymerization process. This work not only provides a facile new method to immobilize ionic liquids on solid surface. Interestingly, without use of any template unique “knit” morphology and nanostructure, even hierarchical structures could also be produced by the electropolymerization of these new functionalized pyrrole monomers. We found that the properties of the pendant ionic liquid units on the surface of the formed polymer films preserved, and by simple anion exchange their surface energy and tension could be easily tuned without loss of the electrical, optical properties, and morphology of the polypyrrole films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4151–4161, 2008
Synthesis and properties of helical poly(phenylacetylene) derivatives. Effect of chirality combination on the helicity
Authors: Liu Ruiyuan , Sanda Fumio , Masuda Toshio 
Published: May 2008

AbstractNovel 4‐ethynylphthaloyl amino acid esters carrying different terminal groups, 4‐ethynylphthaloyl glycine (1S,2R,5S)‐menthyl ester (1), 4‐ethynylphthaloyl glycine (1R,2S,5R)‐menthyl ester (2), 4‐ethynylphthaloyl L‐leucine methyl ester (3), 4‐ethynylphthaloyl L‐leucine (1S,2R,5S)‐menthyl ester (4), 4‐ethynylphthaloyl L‐leucine (1R,2S,5R)‐menthyl ester (5) were synthesized and polymerized with a rhodium catalyst. Polymers with high molecular weights were obtained in 71–92% yields. The helical conformation of the polymers could be tuned by the chirality of the amino acid connected to the backbone, together with the chirality and bulkiness of the terminal pendent groups. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4183–4192, 2008
Cyclometalated 2‐phenylpyridine complex [RuII(o‐C6H4‐py)(MeCN)4]PF6 as a tunable catalyst for living radical polymerization
Authors: Diaz Camacho F. , Le Lagadec R. , Ryabov Alexander D. , Alexandrova L. 
Published: May 2008

AbstractThe cyclometalated complex [RuII(o‐C6H4‐py)(MeCN)4]PF6 (1) with a σ‐RuC bond and four substitutionally labile acetonitrile ligands mediates radical polymerization of different vinyl monomers, viz. n‐butyl acrylate, methyl methacrylate, and styrene, initiated by three alkyl bromides: ethyl 2‐bromoisobutyrate, methyl 2‐bromopropionate, and 1‐phenylethyl bromide. The polymerization requires the presence of Al(OiPr)3 and occurs uncontrollably as a conventional radical process. The variation of the molar ratio of the components of the reaction mixture, such as initiator, Al(OiPr)3 and catalyst, affected the polymerization rates and the molecular weights but did not improve the control. A certain level of control has been achieved by adding 0.5 eq of SnCl2 as a reducing agent. Tin(II) chloride decreased the rate of polymerization and simultaneously the molecular weights became conversion‐dependent and the polydispersities were also narrowed. Remarkably, the level of control was radically improved in the presence of excess of the poorly soluble catalyst (1), when the added amount of (1) was not soluble any more, i.e., under heterogeneous conditions, the system became adjustable and the living polymerization of all three monomers was finally achieved. Possible mechanisms of the (1)‐catalyzed polymerization are discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4193–4204, 2008
Plasma Polymerization of Organovanadium Oxides onto Flexible PET/ITO Substrates for Flexible Electrochromic Devices
Authors: Lin Yung‐Sen , Chen Ching‐Lun 
Published: May 2008

AbstractThe electrochromic properties of VOxCy films deposited onto 40 Ω · square−1 flexible PET/ITO substrates by low‐temperature plasma polymerization were investigated. The organic precursor was carried by Ar/O2 and polymerized by r.f. power at room temperature; the plasma‐polymerized films were proven to provide extraordinary electrochromic properties of light modulation with up to 35.8% of transmittance variance. Cyclic voltammetry and cyclic potentiostatic switching measurements demonstrated that only low driving voltages from −0.6 to 1 V were needed to provide reversible Li+ ion insertion and extraction.magnified image
Formation of self‐assembled metal/silicon nanocomposites
Authors: Granitzer P. , Rumpf K. , Pölt P. , Šimić S. , Krenn H. 
Published: May 2008

AbstractThe fabrication of nanoscopic silicon based membranes has been carried out by using a non‐expensive electrochemical preparation technique. For these purposes an n+‐silicon wafer is anodized to create oriented pores with typical diameters around 50 nm. The length of the channels is up to 50 μm which yields to an aspect ratio of 1000. The channels of these templates are partially filled with a metal, especially a ferromagnetic one to obtain an array of nanostructures. Metal‐deposition within such high aspect ratio pores is a great challenge but could be realized in some extent. The introduced silicon based nanocomposite offers the opportunity to change between different nano‐architectures by accurate adjustment of the electrochemical fabrication parameters. Also the size and spatial distribution of the precipitated metal‐structures within the pores can be varied by altering the galvanic deposition process. Different morphologies and varying metal fillings modify the physical properties (e.g. magnetic behaviour) of the nanocomposite system. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of ultra‐thin glass‐coated amorphous microwires for HF magnetic sensor applications
Authors: Zhukov A. , Ipatov M. , Zhukova V. , García C. , Gonzalez J. , Blanco J. M. 
Published: May 2008

AbstractIn this paper we report novel results on magnetic properties and giant magnetoimpedance (GMI) effect at frequencies between 10 MHz and 500 MHz in ultra‐thin Co–Fe‐rich amorphous glass‐coated microwires with near‐zero magnetostriction constant and with metallic nucleus diameter ranging between 5 μm and 22 μm. Co67.05Fe3.84Ni1.44Si14.47B11.51Mo1.69 glass‐coated amorphous microwires with metallic nucleus diameter ranging between 5 μm and 22 μm and total diameter between 10 μm and 23 μm with vanishing magnetostriction constant of the order of –(1–3) × 10–7 fabricated by the Taylor–Ulitovsky method were studied. Most of the samples studied exhibited excellent soft magnetic behaviour and a large GMI effect. Off‐diagonal components, real and imaginary parts of the GMI were analysed. Even in the thicker samples (metallic nucleus 22 μm) the penetration skin depth calculated from the GMI curves at 30 MHz was about 1 μm. Therefore the surface magnetization process and surface defects are of special importance to achieve good HF properties in these wires. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New non‐volatile logic based on spin‐MTJ
Authors: Zhao Weisheng , Belhaire Eric , Chappert Claude , Jacquet François , Mazoyer Pascale 
Published: May 2008

AbstractAs the minimum dimensions of complementary metal oxide semiconductor (CMOS) transistors shrink down to 90 nm and below, some physical obstacles have been observed which prevent rigidly this miniaturization. For example, high transistor leakage currents lead to an important increase of the ‘idle’ power consumption of CMOS memory arrays. Many nanodevices are therefore the subject of research and development to help CMOS technology continue to downscale by Moore's law. Among them, the magnetic tunnel junction (MTJ) is one of the most promising candidates, because its non‐volatility offers the possibility to power off the chip to greatly reduce the ‘idle’ energy dissipation of conventional CMOS circuits. Moreover, its resistance value property (several kΩ), compatible with CMOS transistor conductivity, allows its states to be sensed easily with CMOS circuits. The novel spin transfer torque (STT) writing approach, which has been recently introduced and developed, reduces significantly the switching energy and data disturbance when compared with the conventional MTJ writing approach. It makes the MTJ technology much more suitable than other nanodevices for commercial applications. In this paper, hybrid STT‐based MTJ (spin‐MTJ)/CMOS logic circuits and some design techniques are proposed based on STMicroelectronics 90 nm CMOS technology and the published Hitachi spin‐MTJ technology. A first prototype has been simulated and evaluated. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrodeposition study of ODN:SWCNT hybrids on gold substrates
Authors: Lahiji Roya R. , Dolash Bridget D. , McDonald Jennifer , Zemlyanov Dmitry , Bergstrom Donald E. , Reifenberger R. 
Published: May 2008

AbstractSonication of short single‐stranded DNA (oligodeoxyribonucleotide; ODN) with Single‐Walled Carbon Nanotubes (SWCNTs) greatly facilitates the dispersion of SWCNTs from entangled ropes in an aqueous solution, creating ODN:SWCNT hybrids. Electrodeposition has been investigated to determine if well‐dispersed ODN:SWCNT hybrids on a metal substrate can be created. Preliminary studies indicate that electrodeposition using an Au substrate held at +0.5 V produces ODN:SWCNT hybrids that are uniformly deposited across the Au substrate. This result can be compared to samples produced by drop casting and evaporation techniques which yield a thick tangled mat of ODN:SWCNT hybrids across the substrate. The resulting electrodeposited samples were characterized using Scanning Probe Microscope (SPM) and X‐ray Photoemission Spectroscopy (XPS) techniques. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pharmacokinetic parameters estimation using adaptive Bayesian P‐splines models
Authors: Jullion Astrid , Lambert Philippe , Beck Benoit , Vandenhende F. 
Published: May 2008

AbstractIn preclinical and clinical experiments, pharmacokinetic (PK) studies are designed to analyse the evolution of drug concentration in plasma over time i.e. the PK profile. Some PK parameters are estimated in order to summarize the complete drug's kinetic profile: area under the curve (AUC), maximal concentration (Cmax), time at which the maximal concentration occurs (tmax) and half‐life time (t1/2).Several methods have been proposed to estimate these PK parameters. A first method relies on interpolating between observed concentrations. The interpolation method is often chosen linear. This method is simple and fast. Another method relies on compartmental modelling. In this case, nonlinear methods are used to estimate parameters of a chosen compartmental model. This method provides generally good results. However, if the data are sparse and noisy, two difficulties can arise with this method. The first one is related to the choice of the suitable compartmental model given the small number of data available in preclinical experiment for instance. Second, nonlinear methods can fail to converge. Much work has been done recently to circumvent these problems (J. Pharmacokinet. Pharmacodyn. 2007; 34:229–249, Stat. Comput., to appear, Biometrical J., to appear, ESAIM P&S 2004; 8:115–131).In this paper, we propose a Bayesian nonparametric model based on P‐splines. This method provides good PK parameters estimation, whatever be the number of available observations and the level of noise in the data. Simulations show that the proposed method provides better PK parameters estimations than the interpolation method, both in terms of bias and precision. The Bayesian nonparametric method provides also better AUC and t1/2 estimations than a correctly specified compartmental model, whereas this last method performs better in tmax and Cmax estimations.We extend the basic model to a hierarchical one that treats the case where we have concentrations from different subjects. We are then able to get individual PK parameter estimations. Finally, with Bayesian methods, we can get easily some uncertainty measures by obtaining credibility sets for each PK parameter. Copyright © 2008 John Wiley & Sons, Ltd.
Introducing the coupling information in a limited‐area variational assimilation
Authors: Guidard Vincent , Fischer Claude 
Published: May 2008

AbstractWe address the problem of how to take advantage, in a limited‐area variational assimilation, of the previously‐performed global data analysis of the coupling system. We expect this information to add value to the limited‐area analysis, since, for example, the global analysis can deal with observations close to but outside the domain of interest. The global analysis is treated as an extra source of information, and we derive the full least‐square error problem for the augmented information vector. We are left with the specifications of a global analysis‐error covariance matrix and extra cross‐covariance terms, expressed in a lower‐resolution grid covering all of the coupled domain. Simplifications are proposed to make the problem algorithmically more tractable, especially in order to benefit from the advances in the ‘modelization’ of the background‐error covariance matrix. Further, we obtain a more classical minimization problem for the sum of three, instead of two, additive cost functions.We have tested the formulation in the framework of the coupled ARPÈGE 4D‐Var and ALADIN‐France 3D‐Var systems. Objective scores with respect to radiosonde and aircraft observations give neutral or slightly positive results for the proposed method. The information‐augmented assimilation cycle produces background 6 h forecasts that are slightly closer to the verifying observations. Subjective case‐by‐case verification does not reveal a visible systematic beneficial impact on the quality of the forecasts, especially for small‐scale parameters such as precipitation. We nevertheless propose to apply the method in future to very high‐resolution assimilation systems, which are likely to be operated on fairly small domains. Copyright © 2008 Royal Meteorological Society