bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trends in adherence to secondary prevention medications in elderly post‐myocardial infarction patients
Authors: Choudhry Niteesh K. , Setoguchi Soko , Levin Raisa , Winkelmayer Wolfgang C. , Shrank William H. 
Published: October 2008

AbstractBackgroundPoor levels of medication adherence for patients with coronary heart disease (CHD) have been documented but it is unclear whether adherence has improved over time.MethodsWe assembled a retrospective cohort of lower‐income Medicare beneficiaries who were discharged from the hospital after their first acute myocardial infarction (MI) between 1 January 1995 and 31 December 2003. For patients prescribed a statin, ACEI/ARB, beta‐blocker, and all 3 of these medications after the hospital discharge, we evaluated medication adherence by determining the proportion of days covered (PDC) for each medication in the subsequent year.ResultsOur cohort consisted of a total of 33 646 patients. Adherence rates for statins and beta‐blockers, but not ACEI/ARB, increased significantly over time but remained suboptimal. For example, among those patients that received a statin after discharge, 38.6% were fully adherent with therapy in 1995 in contrast to 56.2% in 2003 (p value for trend <0.001). Of patients prescribed all 3 of statin, beta‐blocker, and ACEI/ARB, 29.1% and 46.4% were fully adherent in 1995 and 2003, respectively (p value for trend <0.001).ConclusionsOur analysis demonstrates statistically significant but modest improvements in medication adherence for statins and beta‐blockers, but not ACEI/ARBs, among patients discharged from hospital after acute MI. Despite these improvements, rates of non‐adherence to these highly effective therapies remain extremely high. Given the health and economic consequences of non‐adherence, the development of cost‐effective strategies to improve medication adherence should be a clear priority. Copyright © 2008 John Wiley & Sons, Ltd.
A distributed research network model for post‐marketing safety studies: the Meningococcal Vaccine Study
Authors: Velentgas Priscilla , Bohn Rhonda L. , Brown Jeffrey S. , Chan K. Arnold , Gladowski Patricia , Holick Crystal N. , Kramer Judith M. , Nakasato Cynthia , Spettell Claire M. , Walker Alexander M. , Zhang Fang , Platt Richard 
Published: October 2008

AbstractPurposeWe describe a multi‐center post‐marketing safety study that uses distributed data methods to minimize the need for covered entities to share protected health information (PHI). Implementation has addressed several issues relevant to creation of a large scale post‐marketing drug safety surveillance system envisioned by the FDA's Sentinel Initiative.MethodsThis retrospective cohort study of Guillain‐Barré syndrome (GBS) following meningococcal conjugate vaccination incorporates the data and analytic expertise of five research organizations closely affiliated with US health insurers. The study uses administrative claims data, plus review of full text medical records to adjudicate the status of individuals with a diagnosis code for GBS (ICD9 357.0). A distributed network approach is used to create the analysis files and to perform most aspects of the analysis, allowing nearly all of the data to remain behind institutional firewalls. Pooled analysis files transferred to a central site will contain one record per person for approximately 0.2% of the study population, and contain PHI limited to the month and year of GBS onset for cases or the index date for matched controls.ResultsThe first planned data extraction identified over 9 million eligible adolescents in the target age range of 11–21 years. They contributed an average of 14 months of eligible time on study over 27 months of calendar time. MCV4 vaccination coverage levels exceeded 20% among 17–18‐year olds and 16% among 11–13 and 14–16‐year‐old age groups by the second quarter of 2007.ConclusionThis study demonstrates the feasibility of using a distributed data network approach to perform large scale post‐marketing safety analyses and is scalable to include additional organizations and data sources. We believe these results can inform the development of a large national surveillance system. Copyright © 2008 John Wiley & Sons, Ltd.
Alkylating potential of N‐phenyl‐N‐nitrosourea
Authors: Manso J. A. , Pérez‐Prior M. T. , Gómez‐Bombarelli R. , González‐Pérez M. , Céspedes I. F. , García‐Santos M. P. , Calle E. , Casado J. 
Published: October 2008

AbstractAlkylating agents are considered to be archetypical carcinogens. Since the decomposition of alkylnitrosoureas gives rise to alkyldiazonium ions without any need for metabolic activation, they offer an ideal series of compounds with which to examine the effect of variations in chemical structure on alkylating potential. Due to its instability N‐phenyl‐N‐nitrosourea is easily hydrolyzed to a benzenediazonium ion. Since N‐phenyl‐N‐nitrosourea shows a particular behavior when compared with other nitrosoureas, here its alkylating potential was studied. The nucleophile 4‐(p‐nitrobenzyl)pyridine (NBP), a trap for alkylating agents, was used as an alkylation substrate. Conclusions were drawn as follows: (i) the mechanism of the alkylation reaction of NBP by phenylnitrosourea is different from that caused by other nitrosoureas; (ii) the formation of the NBP–N‐phenyl‐N‐nitrosourea adduct occurs about 20,000‐fold slower than with N‐methyl‐N‐nitrosourea, one of the most effective carcinogenic nitrosoureas; and, (iii) a correlation was found between the alkylating potential of nitrosoureas and their tumorigenicity. Copyright © 2008 John Wiley & Sons, Ltd.
PMMA‐grafted dextran glycopolymers by atom transfer radical polymerization
Authors: Dupayage Ludovic , Save Maud , Dellacherie Edith , Nouvel Cecile , Six Jean‐Luc 
Published: October 2008

AbstractThe four‐step synthesis of amphiphilic glycopolymers associating dextran as backbone and poly(methyl methacrylate) (PMMA) as grafts is reported, using the “grafting from” strategy. In the first step, the dextran OH functions were partially acetylated. The second step consisted in linking initiator groups by reaction of 2‐bromoisobutyryl bromide (BiBB) with the unprotected OH functions. Third, the atom transfer radical polymerization (ATRP) of methyl methacrylate was carried out in DMSO from the resulting dextran derivative used as a macroinitiator. Finally, the cleavage of the acetate groups led to the expected glycopolymers. Careful attention was given both to the copolymer structure and the control of polymerization. PMMA grafts were analyzed by SEC‐MALLS after their deliberate cleavage from the backbone to evidence a controlled polymerization. Moreover, the mildness of the final deprotection conditions was proved to ensure acetate cleavage without either degrading dextran backbone and PMMA grafts or cleaving grafts from dextran backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7606–7620, 2008
Synthesis of arborescent (Dendritic) polystyrenes via controlled inimer‐type reversible addition‐fragmentation chain transfer polymerization
Authors: Heidenreich Andrew J. , Puskas Judit E. 
Published: October 2008

AbstractThe reversible addition‐fragmentation chain transfer (RAFT) copolymerization of styrene and 4‐vinylbenzyl dithiobenzoate, a RAFT‐based inimer (initiator‐monomer), is described. Controlled polymerization was achieved in bulk conditions using thermal initiation at 110 °C to give arborescent polystyrene (arbPSt). The number‐average molecular weights of the polymers increased linearly with conversion and were much higher than theoretically calculated for a linear polymerization, reaching Mn = 364,000 g/mol with Mw/Mn = 2.65. Branching analysis by NMR showed an average of 3.5 branches per chain. SEC data, which were similar to those measured in arborescent polyisobutylene, supported the architectural analysis. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7621–7627, 2008
One‐pot synthesis of linear‐hyperbranched diblock copolymers via self‐condensing vinyl polymerization and ring opening polymerization
Authors: Zou Peng , Yang Li‐Ping , Pan Cai‐Yuan 
Published: October 2008

AbstractThe linear poly(ε–caprolacton)‐b‐hyperbrached poly(2‐((α‐bromobutyryl)oxy)ethyl acrylate) (LPCL‐b‐HPBBEA) has been successfully synthesized by simultaneous ring‐opening polymerization (ROP) of CL and self‐condensing vinyl polymerization (SCVP) of BBEA in one‐pot. The HPBBEA homopolymers were found to be formed in the polymerization because of the competitive reactions induced by initiation with bifunctional initiator, 2‐hydroxylethyl‐2′‐bromoisobutyrate (HEBiB), and inimer BBEA. The separation of LPCL‐b‐HPBBEA from the polymerization products was achieved by precipitation in methanol. With feed ratio increase of CL and BBEA to HEBiB, the molecular weights of PCL and HPBBEA blocks in the block copolymer enhanced; and the polymerization rate of CL started to decrease gradually after 12 h of polymerization, but the polymerization rate of BBEA was maintained until 24 h of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7628–7636, 2008
Synthesis of poly(methyl acrylate) loops grafted onto silica nanoparticles via reversible addition‐fragmentation chain transfer polymerization
Authors: Rotzoll Robert , Vana Philipp 
Published: October 2008

AbstractReversible addition‐fragmentation chain transfer (RAFT) polymerization was used to produce poly(methyl acrylate) (pMA) loops grafted onto silica nanoparticles using doubly anchored bifunctional RAFT agents 1,4‐bis(3′‐trimethoxysilylpropyltrithiocarbonylmethyl)benzene (Z‐group approach) and 1,6‐bis(o,p‐2′‐trimethoxysilylethylbenzyltrithiocarbonyl)hexane (R‐group approach) as mediators. In both cases, molecular weights of the resulting surface‐confined polymer loops increased with monomer conversion, whereas the grafting density was significantly higher in the case of the R‐group supported RAFT polymerization due to mechanistic differences of the RAFT process at the surface. This result was evident from thermogravimetric analysis and supported by scanning electron microscopy. Polymer loops with molecular weights up to 53,000 g mol−1 were accessible with polydispersities of about 2.0 without and 1.5 with the addition of free RAFT agent. UV signals of the detached pMA loops measured via size exclusion chromatography were shifted to higher molecular weights compared with the corresponding RI signals, indicating branching reactions caused by the close proximity of growing radicals and polymer at the surface of the silica nanoparticles. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7656–7666, 2008
Synthesis, characterization, and self‐assembly of ion‐bonded A2B rod‐coil copolymer with oligo(para‐phenyleneethynylene) as rod segment
Authors: Lu Dairen , Tao Kang , Wang Yun , Bai Ruke 
Published: October 2008

AbstractSupramolecular A2B rod‐coil copolymer, composed of two polystyrene (PSt) arms and one oligo(para‐phenyleneethynylene) (OPE) arm linked via ionic bond, has been designed and successfully synthesized. First, a trifunctional initiator, methyl 1,3‐bis(bromomethyl)benzonate, was prepared and used to initiate the polymerization of styrene under atom transfer radical polymerization (ATRP) condition to provide polystyrene (PSt) carrying monoester group at the middle of polymer chain. Then, the ester group was transferred into tertiary amino group to give amino‐functionalized PSt, (PSt)2N(CH3)2. Subsequently, the ion‐bonded rod‐coil copolymer, (PSt)2OPE, was obtained by the reaction of (PSt)2N(CH3)2 with carboxy‐terminated OPE (OPECOOH). The resulting copolymer was characterized by nuclear magnetic resonance (NMR), Fourier transformer infrared (FTIR), and gel permeation chromatography (GPC) techniques. Vesicles and spherical micelles were generated from this supramolecular rod‐coil copolymer through the manipulation of the initial polymer concentration in toluene. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7667–7676, 2008
Mechanism and characterization of alkylene‐ and p‐ethylenebenzylene‐spaced polycarbosilanes ceramic precursor synthesized by electropolymerization
Authors: Cabasso Israel , Yuan Youxin , Wang Xinwei 
Published: October 2008

AbstractAn electropolymerization of haloalkylhalosilanes (ClRSiCH3Cl2) that possess two types of electroactive sites, that is, the CCl and SiCl bond is described. The one‐pot synthesis method is shown to yield branched polycarbosilanes having a regular carbon block‐spaced silicon backbone structure. A series of branched polycarbosilanes, [RSiCH3]n with R being CH2, C2H4, C3H6, and CH2C6H4C2H4, have been successfully electropolymerized with Mn up to 42,600 Dalton. Experimental and simulation cyclic voltammetry of these monomers and the computational examination of their LUMOs are applied to study the electropolymerization mechanism. The results suggest that polymerization proceeds by iterating steps involving (1) electroreduction of a CCl bond to a carbanion, which is catalyzed by silylanion radical [Cl
SiCl(CH3)RCl]
and/or Ni(0)/TDA‐1; and (2) nucleophilic attack of carbanions to SiCl bonds of a second monomer or oligomer to extend the polymer chain. The investigation reveals that the R spacer has a considerable impact on the polymerizability of the corresponding monomer. Such interfacial polymerization resembles a template polymerization, leading to unique microstructures that were preserved even after converted to silicon carbide ceramics at high temperatures. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7677–7689, 2008
Synthesis of chiral amphiphilic diblock copolymers via consecutive RAFT polymerizations and their aggregation behavior in aqueous solution
Authors: Wang Jian , Xu Wenliang , Cheng Zhenping , Zhu Xiulin , Zhang Zhengbiao , Zhu Jian , Zhang Wei 
Published: October 2008

AbstractTwo chiral amphiphilic diblock copolymers with different relative lengths of the hydrophobic and hydrophilic blocks, poly(6‐O‐p‐vinylbenzyl‐1,2:3,4‐Di‐O‐isopropylidene‐D‐galactopyranose)‐b‐poly(N‐isopropylacrylamide) or poly(VBCPG)‐b‐poly(NIPAAM) and poly(20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one methacrylate)‐b‐poly(N‐isopropylacrylamide) or poly(MAC‐HPD)‐b‐poly(NIPAAM) were synthesized via consecutive reversible addition‐fragmentation chain‐transfer polymerizations of VBCPG or MAC‐HPD and NIPAAM. The chemical structures of these diblock copolymers were characterized by 1H nuclear magnetic resonance spectroscopy. These amphiphilic diblock copolymers could self‐assemble into micelles in aqueous solution, and the morphologies of micelles were investigated by transmission electron microscopy. By comparison with the lower critical solution temperatures (LCST) of poly(NIPAAM) homopolymer in deionized water (32 °C), a higher LCST of the chiral amphiphilic diblock copolymer (poly(VBCPG)‐b‐poly(NIPAAM)) was observed and the LCST increased with the relative length of the poly(VBCPG) block in the copolymer from 35 to 47 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7690–7701, 2008
Synthesis of terpyridine ligands and their complexation with Zn2+ and Ru2+ for optoelectronic applications
Authors: Vellis Panagiotis D. , Mikroyannidis John A. , Lo Chih‐Nan , Hsu Chain‐Shu 
Published: October 2008

AbstractA series of soluble conjugated ligands TT, FT, PT, and NT that contained terpyridyl terminal units were synthesized by Heck coupling. These ligands absorbed at 341–434 nm and emitted blue–green light, with maximum at 440–522 nm and photoluminescence quantum yields of 0.15–0.71 in solution. The double‐layer electroluminescent devices with the configuration of ITO/PEDOT/ligand FT, PT, or NT/Ca/Al exhibited a brightness of 43–63 cd/m2. These ligands were further reacted with zinc(II) and ruthenium(II) ions and subsequent anion exchange to afford linear and supramolecular complexes. The photophysics of these complexes were investigated. A significant redshift of the emission maximum of the Zn complexes relative to the corresponding ligands was observed. The Ru complexes were used to fabricate photovoltaic devices with the structure ITO/PEDOT/Ru complex/P3HT:PCBM (1:1 wt/wt)/Ca/Al. The power conversion efficiency of these polymer–fullerene bulk heterojunction photovoltaic devices was up to 0.71%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7702–7712, 2008
Polymer brushes containing sulfonated sugar repeat units: Synthesis, characterization, and in vitro testing of blood coagulation activation
Authors: Ayres N. , Holt D. J. , Jones C. F. , Corum L. E. , Grainger D. W. 
Published: October 2008

AbstractA new polymer brush chemistry containing sulfonated carbohydrate repeat units has been synthesized from silicon substrates using ATRP methods and characterized both in bulk and using surface analysis. The polymer brush was designed to act as a mimic for the naturally occurring sulfonated glycosaminoglycan, heparin, commonly used for modifying blood‐contacting surfaces both in vitro and in vivo. Surface analysis showed conversion of brush saccharide precursor chemistry to the desired sulfonated polymer product. The sulfonated polymer brush surface was further analyzed using three conventional in vitro tests for blood compatibility—plasma recalcification times, complement activation, and thrombin generation. The sulfonated polymer brush films on silicon oxide wafers exhibited better assay performance in these blood component assays than the unsulfonated sugar functionalized polymer brush in all tests performed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7713–7724, 2008
Synthesis, photophysics, theoretical modeling, and electroluminescence of novel 2,7‐carbazole‐based conjugated polymers with sterically hindered structures
Authors: Tang Weihua , Lin Tingting , Ke Lin , Chen Zhi‐kuan 
Published: October 2008

Abstract2,7‐dibromo‐N‐hexylcarbazole is successfully synthesized in three steps with an overall 37% yield. Novel 2,7‐carbazole‐based sterically hindered conjugated polymers are further synthesized. In the backbone structure of polymer P1, alkylated bithiophene moiety is β‐substituted with dodecyl chains on both thiophene rings, adopting the tail‐to‐tail configuration. While for polymers P2 and P3, partially planarized thieno[3,2‐b]thiophene moiety (P2) and β‐pentyl substituted thieno[3,2‐b]thiophene (P3) are incorporated. All polymers demonstrate efficient blue‐to‐green light emission, good thermal stability (Td ≥ 379 °C), and high glass transition temperatures (Tg = 118 °C). The optical and electronic properties of the resulted polymers are tuned by the incorporated alkyl chains. For instance, the incorporation of β‐pentyl group in thieno[3,2‐b]thiophene moiety endows P3 with blue‐shifted photophysical spectra, reduced fluorescence quantum yield and larger band gap in comparison with P2. The steric effect of incorporated alkyl chains is further illustrated by geometry optimization of three model oligomers (analogues to the repetition units of P1–P3) using density functional theory. Sterically hindered polymers P1 and P2 exhibit high charge transport ability and moderate electroluminescent properties in primarily tested single‐layer light‐emitting diodes (configuration: ITO/PEDOT:PSS/Polymer/Ca/Ag). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7725–7738, 2008
The synthesis and self‐assembly of ABA amphiphilic block copolymers containing styrene and oligo(ethylene glycol) methyl ether methacrylate in dilute aqueous solutions: Elevated cloud point temperatures for thermoresponsive micelles
Authors: Holder Simon J. , Durand Geraldine G. , Yeoh Chert‐Tsun , Illi Elodie , Hardy Nicholas J. , Richardson Tim H. 
Published: October 2008

AbstractA series of ABA amphiphilic triblock copolymers possessing polystyrene (PS) central hydrophobic blocks, one group with “short” PS blocks (DP = 54–86) and one with “long” PS blocks (DP = 183–204) were synthesized by atom transfer radical polymerization. The outer hydrophilic blocks were various lengths of poly(oligoethylene glycol methyl ether) methacrylate, a comb‐like polymer. The critical aggregation concentrations were recorded for certain block copolymer samples and were found to be in the range circa 10−9mol L−1for short PS blocks and circa 10−12mol L−1for long PS blocks. Dilute aqueous solutions were analyzed by transmission electron microscopy (TEM) and demonstrated that the short PS block copolymers formed spherical micelles and the long PS block copolymers formed predominantly spherical micelles with smaller proportions of cylindrical and Y‐branched cylindrical micelles. Dynamic light scattering analysis results agreed with the TEM observations demonstrating variations in micelle size with PS and POEGMA chain length: the hydrodynamic diameters (DH) of the shorter PS block copolymer micelles increased with increasing POEGMA block lengths while maintaining similar PS micellar core diameters (DC); in contrast the values ofDHandDCfor the longer PS block copolymer micelles decreased. Surface‐pressure isotherms were recorded for two of the samples and these indicated close packing of a short PS block copolymer at the air–water interface. The aggregate solutions were demonstrated to be stable over a 38‐day period with no change in aggregate size or noticeable precipitation. The cloud point temperatures of certain block copolymer aggregate solutions were measured and found to be in the range 76–93 °C; significantly these were ∼11 °C higher in temperature than those of POEGMA homopolymer samples with similar chain lengths. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7739–7756, 2008
Synthesis of inverse star block copolymer by combination of ATRP, ring opening polymerization, and “click chemistry”
Authors: Yang Li‐Ping , Dong Xue‐Hui , Pan Cai‐Yuan 
Published: October 2008

AbstractThe inverse star block copolymer, (poly(ε‐caprolactone)‐b‐polystyrene)2‐core‐(poly(ε‐caprolactone)‐b‐polystyrene)2, [(PCL‐PS)2‐core‐(PCL‐PS)2] has been successfully prepared by combination of atom transfer radical polymerization (ATRP), ring opening polymerization (ROP), and “Click Chemistry.” The synthesis includes the following five steps: (1) synthesis of a heterofunctional initiator with two ATRP initiating groups and two hydroxyl groups; (2) formation of (Br‐PS)2‐core‐(OH)2 via ATRP of styrene; (3) preparation of the (PCL‐PS)2‐core‐(OH)2 through “click” reaction of the α‐propargyl, ω‐acetyl terminated PCL with (N3‐PS)2‐core‐(OH)2 which was prepared by transformation of the terminal bromine groups in (Br‐PS)2‐core‐(OH)2 into azide groups; (4) the ROP of CL using (PCL‐PS)2‐core‐(OH)2 as macroinitiator to form (PCL‐PS)2‐core‐(PCL‐OH)2; and (5) preparation of the (PCL‐PS)2‐core‐(PCL‐PS)2 through the ATRP of styrene using (PCL‐PS)2‐core‐(PCL‐Br)2 as macroinitiator which was prepared by reaction of the terminal hydroxyl groups at the end of the PCL chains with 2‐bromoisobutyryl bromide. The characterization data support structures of the inverse star block copolymer and the intermediates. The differential scanning calorimeter results and polarized optical microscope observation showed that the intricate structure of the inverse star block copolymer greatly restricted the movement of the PS segments and PCL segments, resulted in the increase of the glass transition temperature of PS segments and the decrease of crystallization ability of PCL segments. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7757–7772, 2008