bluuebunny/crossref_metadata_2025 huggingface dataset:
Colloid‐Assisted Self‐Assembly of Robust, Three‐Dimensional Networks of Carbon Nanotubes over Large Areas
Authors: Jurewicz Izabela , King Alice A. K. , Worajittiphon Patnarin , Asanithi Piyapong , Brunner Eric W. , Sear Richard P. , Hosea Thomas J. C. , Keddie Joseph L. , Dalton Alan B.
Published: February 2010

Natural materials, such as bone and spider silk, possess remarkable properties as a result of sophisticated nanoscale structuring. They have inspired the design of synthetic materials whose structure at the nanoscale is carefully engineered or where nanoparticles, such as rods or wires, are self‐assembled. Although much work has been done in recent years to create ordered structures using diblock copolymers and template‐assisted assembly, no reports describe highly ordered, three‐dimensional nanotube arrays within a polymeric material. There are only reports of two‐dimensional network structures and structures on micrometer‐size scales. Here, we describe an approach that uses plasticized colloidal particles as a template for the self‐assembly of carbon nanotubes (CNTs) into ordered, three‐dimensional networks. The nanocomposites can be strained by over 200% and still retain high conductivity when relaxed. The method is potentially general and so may find applications in areas such as sensing, photonics, and functional composites.

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Preparation of Clickable Poly(3‐hydroxyalkanoate) (PHA): Application to Poly(ethylene glycol) (PEG) Graft Copolymers Synthesis
Authors: Babinot Julien , Renard Estelle , Langlois Valérie
Published: February 2010

A new synthesis of amphiphilic biodegradable copolymers consisting of hydrophobic poly(3‐hydroxyalkanoate) (PHA) backbone and hydrophilic poly(ethylene glycol) (PEG) units as side chains is described. Poly[(3‐hydroxyoctanoate)‐co‐(3‐hydroxyundecenoate)] (PHOU) was first methanolyzed and its unsaturated side chains were quantitatively oxidized to carboxylic acid. Esterification with propargyl alcohol led to an alkyne‐containing “clickable” PHA in 71% conversion. Its reactivity was successfully demonstrated by grafting azide‐terminated PEG chains of 550 and 5 000 g · mol−1, respectively. All products were fully characterized using GPC, 1H, and COSY NMR.

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Prevalence and cost of medication nonadherence in Parkinson's disease: Evidence from administrative claims data
Authors: Davis Keith L. , Edin Heather M. , Allen Jeffery K.
Published: February 2010

We estimated the prevalence of medication nonadherence in Parkinson's disease (PD) and the association between treatment nonadherence and healthcare costs. Insurance claims from over 30 US health plans were analyzed. Inclusion criteria were as follows: PD diagnosis, ≥1 PD‐related prescription between 1/1/1997 and 12/31/2004, continuous health plan enrollment for ≥6 months before and ≥12 months after first PD prescription. Adherence, all‐cause healthcare utilization, and all‐cause costs were evaluated over 12 months post‐treatment initiation. Adherence was measured using the medication possession ratio (MPR), with MPR < 0.8 defining nonadherence. Among patients identified for inclusion (N = 3,119), 58% were male and mean age was 69 years. Mean MPR was 0.58 and 61% of patients were nonadherent. Unadjusted mean medical costs were significantly higher (P < 0.01) among nonadherers ($15,826) compared with adherers ($9,228), although nonadherers had lower prescription drug costs ($2,684 vs. $3,854; P < 0.05). After controlling for confounders in multivariable analyses, a large positive relationship between nonadherence and both medical and total healthcare costs remained (+$3,451, P < 0.0001 and +$2,383, P = 0.0053, respectively). Medication adherence in PD is suboptimal and nonadherence may be associated with increased healthcare costs despite offsets from reduced drug intake. Efforts to promote medication adherence in PD may lead to cost savings for managed care systems. © 2010 Movement Disorder Society
Descriptions of Cervical Dystonia by Sir Charles Bell
Authors: Gonzalez‐Alegre Pedro
Published: February 2010

Sir Charles Bell is better known among neurologists for his descriptions of the clinical consequences of facial nerve lesions. However, as an accomplished physician, anatomist, and artist, he made many other contributions to the fields of neurology and neuroscience. Among those, his descriptions of patients with what we now know as cervical dystonia have not received much attention. In this report, Bell's depictions of patients presenting with a syndrome consistent with cervical dystonia will be discussed, including the identification of many of the different clinical features we currently use for the diagnosis of this disorder and his thoughts about its pathogenesis. © 2010 Movement Disorder Society
Four‐week trunk‐specific rehabilitation treatment improves lateral trunk flexion in Parkinson's disease
Authors: Bartolo Michelangelo , Serrao Mariano , Tassorelli Cristina , Don Romildo , Ranavolo Alberto , Draicchio Francesco , Pacchetti Claudio , Buscone Simona , Perrotta Armando , Furnari Anna , Bramanti Placido , Padua Luca , Pierelli Francesco , Sandrini Giorgio
Published: February 2010

People with Parkinson's disease (PD) often have a posture characterized by lateral trunk flexion poorly responsive to antiparkinsonian drugs. To examine the effects of a rehabilitation programme (daily individual 90‐minute‐sessions, 5‐days‐a‐week for 4‐consecutive weeks) on lateral trunk flexion and mobility, 22 PD patients with mild to severe lateral trunk flexion, and 22 PD patients without trunk flexion were studied. Patients were evaluated using the Unified Parkinson's Disease Rating Scale motor subscale (UPDRS‐III) score, and the kinematic behavior of the trunk was recorded by means of an optoelectronic system to determine: a) trunk flexion, inclination and rotation values in the erect standing posture; b) ranges of trunk flexion and inclination during trunk movements. After the treatment, significant decreases in trunk flexion [24°(4) vs. 14°(3), P < 0.001] and inclination in the static condition [23°(5) vs. 12°(4), P < 0.001)] were observed, both of which were maintained at the 6‐month follow up. During the trunk flexion task, a significantly increased range of trunk flexion [64°(15) vs. 83°(15), P < 0.001] was observed; similarly, during the lateral bending task, the range of trunk inclination was found to be significantly increased, both toward the side of the trunk deviation [29°(8) vs. 42°(13), P < 0.01] and toward the contralateral side [14°(6) vs 29°(11), P < 0.01]. No further significant changes were observed at the 6‐month follow‐up. Trunk flexion and inclination values in the upright standing posture correlated slightly with the UPDRS‐III score. Our findings show that significant improvements in axial posture and trunk mobility can be obtained through the 4‐week rehabilitation programme described, with a parallel improvement in clinical status. © 2010 Movement Disorder Society
A case‐control study on restless legs syndrome in nondialyzed patients with chronic renal failure
Authors: Merlino Giovanni , Lorenzut Simone , Gigli Gian Luigi , Romano Giulio , Montanaro Domenico , Moro Alessandro , Valente Mariarosaria
Published: February 2010

Restless legs syndrome (RLS) is a possible consequence of end‐stage renal disease. However, conclusive data on the association between RLS and chronic renal failure (CRF) in nondialyzed patients are still lacking. The aims of this study were: (1) to look for an association between RLS and CRF in nondialyzed patients; (2) to analyze the characteristics of RLS and its consequences on nocturnal rest in nondialyzed patients with CRF; (3) to identify possible predictors of RLS occurrence in nondialyzed patients with CRF. We recruited 138 nondialyzed patients with CRF (mean age: 69.8 ± 11.7 years; male: 61.6%) and 151 controls (mean age: 60.2 ± 18.6 years; male: 42.4%). An expert in sleep medicine investigated the presence of RLS by means of a face‐to‐face interview. Fifteen nondialyzed CRF patients and five controls were diagnosed as RLS affected. A multivariate analysis confirmed that RLS was independently associated with CRF in nondialyzed patients (P = 0.004). CRF patients RLS+ were more commonly women and showed the presence of an iron deficiency compared with the RLS− ones. Independent predictors of RLS in nondialyzed CRF patients were: female sex (OR: 10.7, 95% CI: 2.2–31.3; P = 0.004) and percentage of transferrin saturation (OR: 0.6, 95% CI: 0.4–0.9; P = 0.04). This is the first case‐control study able to recognize an association between RLS and CRF in patients not yet on dialysis. Nephrologists should investigate and treat RLS in their nondialyzed patients with CRF. In particular, physicians should carefully investigate women and patients with iron deficiency in the presence of RLS symptoms. © 2010 Movement Disorder Society
Distinguishing SWEDDs patients with asymmetric resting tremor from Parkinson's disease: A clinical and electrophysiological study
Authors: Schwingenschuh Petra , Ruge Diane , Edwards Mark J. , Terranova Carmen , Katschnig Petra , Carrillo Fatima , Silveira‐Moriyama Laura , Schneider Susanne A , Kägi Georg , Palomar Francisco J , Talelli Penelope , Dickson John , Lees Andrew J. , Quinn Niall , Mir Pablo , Rothwell John C. , Bhatia Kailash P.
Published: February 2010

Approximately 10% of patients diagnosed clinically with early Parkinson's disease (PD) have normal dopaminergic functional imaging (Scans Without Evidence of Dopaminergic Deficit [SWEDDs]). An important subgroup of SWEDDs are those with asymmetric rest tremor resembling parkinsonian tremor. Clinical and pathophysiological features which could help to distinguish SWEDDs from PD have not been explored. We therefore studied clinical details including non‐motor symptoms in 25 tremulous SWEDDs patients in comparison to 25 tremor‐dominant PD patients. Blinded video rating was used to compare examination findings. Electrophysiological tremor parameters and also response to a cortical plasticity protocol using paired associative stimulation (PAS) was studied in 9 patients with SWEDDs, 9 with tremor‐dominant PD (with abnormal dopamine transporter single photon emission computed tomography findings), 8 with segmental dystonia, and 8 with essential tremor (ET). Despite clinical overlap, lack of true bradykinesia, presence of dystonia, and head tremor favored a diagnosis of SWEDDs, whereas re‐emergent tremor, true fatiguing or decrement, good response to dopaminergic drugs, and presence of non‐motor symptoms favored PD. A single tremor parameter could not differentiate between groups, but the combination of re‐emergent tremor and highest tremor amplitude at rest was characteristic of PD tremor. SWEDDs and segmental dystonia patients exhibited an abnormal exaggerated response to the PAS protocol, in contrast to a subnormal response in PD and a normal response in ET. We conclude that despite clinical overlap, there are features that can help to distinguish between PD and SWEDDs which may be useful in clinical practice. The underlying pathophysiology of SWEDDs differs from PD but has similarities with primary dystonia. © 2010 Movement Disorder Society
General lessons from large‐scale studies to identify human cancer predisposition genes. J Pathol 2010; 220: 255–262
Authors: Cazier Jean‐Baptiste , Tomlinson Ian
Published: February 2010

The original article to which this Erratum refers was published in The Journal of Pathology 2010; 220: 255‐262
Functional expression of the chemokine receptor XCR1 on oral epithelial cells
Authors: Khurram Syed A , Whawell Simon A , Bingle Lynne , Murdoch Craig , McCabe Brenka M , Farthing Paula M
Published: February 2010

Chemokines are chemoattractant cytokines which act on specific receptors and play an important role in leukocyte migration as well as physiological and pathological processes. We investigated the role of the chemokine receptor XCR1 and its ligand lymphotactin (Lptn/XCL1) in the regulation of oral epithelial cell behaviour. In vitro XCR1 mRNA and cell surface protein expression was detected in normal oral keratinocytes and oral squamous cell carcinoma cell lines. Lymphotactin mediated intracellular activation of the ERK1/2 signalling pathway and stimulated migration, invasion, and proliferation of all cells through XCR1. Oral cancer cells showed a greater response to lymphotactin than normal keratinocytes and a direct relationship between receptor expression and migration, invasion, and proliferation was observed. Exposure of normal keratinocytes to lymphotactin resulted in increased adhesion to fibronectin but not collagen and stimulated MMP‐2 and MMP‐9 but not MMP‐7 release, whereas exposure of cancer cells resulted in increased adhesion to both collagen and fibronectin and stimulated production of MMP‐2, MMP‐9, and MMP‐7. We observed XCR1 but not lymphotactin to be expressed by epithelial cells in normal oral mucosa in vivo, whilst both were expressed and up‐regulated in inflammatory oral disease and oral cancer including primary and metastatic disease. Lymphotactin mRNA and constitutive intracellular protein were detected in normal keratinocytes and oral cancer cell lines in vitro. These findings show that XCR1 and its ligand, lymphotactin, are expressed by oral epithelial cells and suggest that they play a role in regulating the behaviour of these cells. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Validation of ischemic cerebrovascular diagnoses in the health improvement network (THIN)
Authors: Ruigómez Ana , Martín‐Merino Elisa , Rodríguez Luis Alberto García
Published: February 2010

Purpose

To evaluate the validity of recorded diagnoses of ischemic cerebrovascular events requiring hospitalization within The Health Improvement Network (THIN) UK primary care database.

Methods

We identified 15 397 individuals aged 40–84 years with a first recorded ischemic event in 2000–2004. Of these, 4239 had a code suggestive of a hospitalization within 2 weeks of the event. A three‐step strategy was used to validate the records of these patients: manual review of computerized medical records excluding free‐text comments; manual review including free‐text comments (which include information gained from specialists, hospital discharge letters and results of diagnostic tests) of a random sample of possible cases (n = 300) and non‐cases (n = 100); and review of full medical records of this random sample and a questionnaire completed by their primary care physician. The positive predictive value (PPV) of each step was calculated. The confirmation rate was used to estimate incidence in the general population.

Results

After step 1, 3447 individuals were classified as possible cases and 792 were excluded as non‐cases. After step 2, 82% of possible cases were still classified as such. Step 3 showed that inclusion of free‐text comments increased the PPV of a diagnosis from 76 to 86%. The weighted incidence of hospitalized ischemic cerebrovascular events was 1.73 per 1000 person‐years (95% CI:1.68–1.77).

Conclusions

THIN demonstrates a high validity for the study of ischemic cerebrovascular events when reviewing computer records with additional free‐text comments. Accuracy of hospitalization status was not as well recorded. Copyright © 2010 John Wiley & Sons, Ltd.
Electromechanical stability of a Mooney–Rivlin‐type dielectric elastomer with nonlinear variable permittivity
Authors: Liu Yanju , Liu Liwu , Sun Shouhua , Leng Jinsong
Published: February 2010

The electromechanical stability of a Mooney–Rivlin‐type dielectric elastomer undergoing large deformation with nonlinear permittivity is investigated. The stability is analyzed by applying a new kind of free energy model, which couples Ogden elastic strain energy and electric field energy density with nonlinear permittivity. Then, nominal electric field and nominal electric displacement of the dielectric elastomer are introduced. Based on this, the electromechanical stability of the Mooney–Rivlin‐type dielectric elastomer is analyzed by simplifying the Ogden elastic strain energy. The critical breakdown electric fields under the conditions of two stretching ratios and various material constant ratios k (n = km, where m and n are material constants in the Ogden model, determined experimentally) are also obtained. According to the simulation results, for a larger dimensionless constant k of the dielectric material, the critical nominal electric field is higher, the corresponding dielectric elastomer or structure is more stable and the electromechanical stability of the dielectric elastomer is proved to be markedly enhanced by a pre‐stretching process. These results agree well with experimental data and can be used as guidance in the design and fabrication of dielectric elastomer actuators. Copyright © 2010 Society of Chemical Industry
MS characterization of qualitative protein polymorphisms in the spinal cords of inbred mouse strains
Authors: Mikkat Stefan , Lorenz Peter , Scharf Christian , Yu Xinhua , Glocker Michael O. , Ibrahim Saleh M.
Published: February 2010

The spinal cord proteomes of two inbred mouse strains with different susceptibility to experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis, were investigated by 2‐DE and MALDI‐MS. A proteome map comprising 304 different protein species was established. Using 2‐D fluorescence difference gel electrophoresis, a comparison of the mouse strains revealed 26 qualitatively polymorphic proteins with altered electrophoretic mobility. MS analyses and DNA sequencing were applied to characterize their structural differences and 14 single amino acid substitutions were identified. Moreover, analysis of selectively enriched phosphopeptides from the neurofilament heavy polypeptide of both mouse strains revealed a high degree of diversity in the phosphorylated C‐terminal domains of this protein. The described approach is capable to structurally characterize qualitative protein polymorphisms, whereas their functional significance remains to be elucidated. For some proteins formerly associated with experimental autoimmune encephalomyelitis and/or multiple sclerosis structural polymorphisms are described here, which may be subjected to further investigations. In addition, this work should be of general interest for proteomic analysis of inbred strains, because it shows potentials and constraints in the use of 2‐DE analysis and MALDI‐MS to detect and characterize structural protein polymorphisms.
Gas‐phase basicities of acetophenones toward lanthanum cation [La(OMe)]
Authors: Than Soe , Badal Md. Mizanur Rahman , Itoh Shuhei , Mishima Masaaki
Published: February 2010

The relative free energy changes (lanthanum cation basicity, LaCB[L2]) for the reaction [La(OMe)2]L ⇌ La(OMe) + 2L were determined in the gas phase for m‐ and p‐substituted acetophenones based on the measurement of ligand exchange equilibria using an FT‐ICR mass spectrometer. The substituent effect on ΔLaCB[L2] of acetophenone is described in terms of the Yukawa–Tsuno equation, ΔG = ρ(σ° + r+ Δ σ), with a ρ value of −11.2 and an r+ value of 0.49. From this result, a ρ value of −7.0 and an r+ value of 0.49 were estimated for the monomeric complex [LLa(OMe)] with the aid of theoretical calculations. This ρ value was found to be significantly smaller than that for protonation, and even smaller than Li+ basicity. Such a small ρ value has been attributed to the largely ionic (ion–dipole interaction) nature of the bonding interaction between La(OMe) and the carbonyl oxygen atom and, in part, to the long distance between La(OMe) and the substituent. Contrary to the ρ value, the r+ value is identical in both La(OMe) and Li+ basicities, suggesting that the r+ value of 0.49 can be regarded as a limiting one in a series of Lewis cation basicities of the acetophenone system, H+ (0.86) > Me3Si+ (0.75) > Me3Ge+ (0.71) > Cu+ (0.60) > Li+ = La(OMe) (0.49). Since the binding interaction between La(OMe) or Li+ and a neutral ligand is mostly electrostatic, the moderate r+ was interpreted to result from the redistribution of the induced positive charge within the acetophenone moiety upon binding with a metal ion rather than transfer of positive charge from a metal ion to the aromatic moiety. Copyright © 2010 John Wiley & Sons, Ltd.
How quantum tunnelling can contribute to proton transfer at biologically relevant temperatures
Authors: Horsewill A. J.
Published: February 2010

The double proton transfer reaction in the bridging hydrogen bonds of carboxylic acid dimers provides a model system for investigating the fundamental physics underpinning the role of quantum tunnelling in molecular dynamics. The behaviour of this system is used to discuss the possible role that tunnelling plays in the molecular dynamics that characterise more complex biological systems at high temperature. Copyright © 2010 John Wiley & Sons, Ltd.
A DFT study on the mechanisms for gas phase reaction of yttrium with propene
Authors: Li Tao Hong , Xie Xiao Guang
Published: February 2010

The gas phase reaction of ground‐state yttrium (Y) with propene, previously examined by crossed molecular beams (CMBs) experiment, has been theoretically investigated in detail using B3LYP method. Three concerted and five stepwise pathways were found for H2 elimination. The calculated PESs indicate that the concerted mechanisms are energetically much more favorable than the stepwise mechanisms for the elimination of H2. Three isomers, Y‐propyne, Y‐allene, and Y(CHCHCH2), were assigned to the experimentally observed H2‐elimination product, YC3H4. Three pathways were identified for the CC bond cleavage products, YCH2 + C2H4. The energetically most favorable pathway involves the formation of a metallacyclobutane intermediate, which can decay to YCH2 + C2H4. The results of this study confirmed some previous inferences and provided more details for the title reaction. Copyright © 2010 John Wiley & Sons, Ltd.
Chemically amplified photoresists for 193‐nm photolithography: Effect of molecular structure and photonic parameters on photopatterning
Authors: Ridaoui Hassan , Dirani Ali , Soppera Olivier , Ismailova Esma , Brochon Cyril , Schlatter Guy , Hadziioannou Georges , Tiron Raluca , Bandelier Philippe , Sourd Claire
Published: February 2010

Next generations of microelectronic devices request further miniaturized systems. In this context, photolithography is a key step and many efforts have been paid to develop new irradiation setup and materials compatible with sub‐100 nm resolution. Among other resist platforms, chemically amplified photoresists (CAR) are widely used because of their excellent properties in terms of resolution, sensitivity, and etching resistance. However, low information on the impact of the polymer structure on the lithography performance is available. CAR with well‐controlled polymer structures were thus prepared and investigated. In particular, the impact of the polymer structure on the lithographic performance was evaluated. Linear and branched polymers with various molecular weights and polydispersities were compared. We focused on the dependency of the photosensitivity of the resist with the structural parameters. These results allow further understanding the fundamental phenomena involved by 193‐nm irradiation. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1271–1277, 2010
Sol‐gel transition behavior of amphiphilic comb‐like poly[(PEG‐b‐PLGA)acrylate] block copolymers
Authors: Park Chung Won , Kim Sung Chul
Published: February 2010

The effects of comb‐like amphiphilic block copolymer architectures on the physical properties such as sol‐gel transition and micellization behaviors with the change of temperature and pH were examined. Comb‐like poly((poly(ethylene glycol)‐b‐(poly(lactic acid‐co‐glycolic acid))acrylate‐co‐acrylic acid) (poly((PEG‐b‐PLGA)A‐co‐AA)) copolymers were synthesized by coupling of poly(acrylic acid) (PAA) with two different kinds of PEG‐b‐PLGA diblock copolymers to investigate the effects of the number of branches and hydrophilicity/hydrophobicity on the sol‐gel transition and micellization. The molecular weights and chemical structures were confirmed by GPC and 1H NMR. The number of PEG‐b‐PLGA branches was gradually deviated from the feed molar ratio with increasing the molecular weight and the number of branches and due to the bulkiness of PEG‐b‐PLGA. Poly[(PEG‐b‐PLGA)A‐co‐AA] aqueous solutions showed thermosensitive sol‐gel transition behavior, and the gelation took place at lower concentration with increasing the number of branches and PLGA chain length due to the increase of hydrophobicity. The temperature, at which abrupt increase of viscosity by dynamic rheometer appeared, was also in good agreement with sol‐gel transition by tube‐titling method. The CMC, calculated from UV‐Visible spectroscopy using DPH as hydrophobic dye, also decreased with increasing the number of PEG‐b‐PLGA branches and PLGA chain length with same reason. The micelle size was increased with increasing temperature at the initial stage, however, decreased with further increase of temperature, since the micelles were, first, aggregated by hydrophobic intermolecular interaction, and then fragmented by dehydration of PEG segments with increasing temperature. PH‐sensitive PAA backbone played a key role in physical properties. With decreasing pH, sol‐to‐gel transition temperature, CMC values, and micelle size were decreased because of the increase of hydrophobicity resulting form non‐ionized acrylic acid. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1287–1297, 2010
Triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands as chemosensors for metal ions
Authors: Cui Yi , Chen Qi , Zhang Dan‐Dan , Cao Jie , Han Bao‐Hang
Published: February 2010

Two well‐defined triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands were synthesized through Suzuki coupling polymerization and were further characterized by 1H‐NMR, 13C‐NMR, gel permeation chromatography, Infrared, and UV‐vis spectra. Polymer P‐1, terpyridine‐bearing poly(triphenylamine‐alt‐fluorene) with a high fluorescence quantum yield (62%) shows much higher sensitivities toward Fe3+, Ni2+, and Cu2+ as compared with the other metal ions investigated. Especially, Fe3+ can lead to an almost complete fluorescence quenching of polymer P‐1. Whereas, the analogous polymer P‐2, in which N‐ethylcarbazole repeat units replace the fluorene units in P‐1, shows a very poor selectivity. It demonstrates that polymers with a same receptor may show different sensitivity to analytes owing to their different type of backbones. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1310–1316, 2010
A facile method for the preparation of monodisperse hollow silica spheres with controlled shell thickness
Authors: Cao Shunsheng , Jin Xin , Yuan Xinhua , Wu Weiwei , Hu Jie , Sheng Weichen
Published: February 2010

This article presents a facile, effective, mild synthesis process for well‐defined hollow spheres by using cationic polystyrene (PS) submicro‐particles as templates. In this approach, the cationic PS templates can be first prepared via emulsifier‐free polymerization by using the cationic monomer 2‐(methacryloyloxy) ethyltrimethylammonium chloride as comonomer, then, the silica shells from the sol‐gel process of tetraethoxysilane were coated on the surfaces of template particles via electrostatic interaction, finally the PS was dissolved in situ by modification of the reaction conditions in the same medium to form monodisperse hollow silica spheres with controlled shell thickness. Fourier transform‐infrared spectroscopy, thermogravimetric analysis, Brunauer‐Emmett‐Teller, transmission electron microscopy, and scanning electron microscope measurements were used to characterize these hollow silica spheres. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1332–1338, 2010
Chemical synthesis and characterization of poly(aniline‐co‐ethyl 3‐aminobenzoate) copolymers
Authors: Gizdavic‐Nikolaidis Marija R. , Zujovic Zoran D. , Ray Sudip , Easteal Allan J. , Bowmaker Graham A.
Published: February 2010

Copolymers of aniline and ethyl 3‐aminobenzoate (3EAB) were synthesized by chemical polymerization in several mole ratios of aniline to functionalized aniline, and their physicochemical properties were compared to those of poly(aniline‐co‐3‐aminobenzoic acid) (3ABAPANI) copolymers. The copolymers were characterized with UV–vis, FTIR, Raman, SEM, EPR, and solid‐state NMR spectroscopy, elemental analysis, and conductivity measurements. The influence of the carboxylic acid and ester group ring substituents on the copolymers was investigated. The spectroscopic studies confirmed incorporation of 3ABA or 3EAB units in the copolymers and hence the presence of CO group in the copolymer chains. The conductivity and EPR signals both decreased with increasing 3EAB content of the copolymers emeraldine salt (ES) form. The conductivity of the ES form of 3ABAPANI was found to be high (1.4 × 10−1 S cm−1) compared with the conductivity (10−2–10−3 S cm−1) of 3EABPANI (ES) copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1339–1347, 2010
Room‐temperature RAFT copolymerization of 2‐chloroallyl azide with methyl acrylate and versatile applications of the azide copolymers
Authors: Li Guang , Wang Hu , Zheng Haiting , Bai Ruke
Published: February 2010

A new vinyl azide monomer, 2‐chlorallyl azide (CAA), has been synthesized from commercially available reagent in one step. The reversible addition fragmentation chain transfer (RAFT) copolymerization of CAA with methyl acrylate (MA) was carried out at room temperature using a redox initiator, benzoyl peroxide (BPO)/N,N‐dimethylaniline (DMA), in the presence of benzyl 1H‐imidazole‐1‐carbodithioate (BICDT). The polymerization results showed that the process bears the characteristics of controlled/living radical polymerizations, such as the molecular weight increasing linearly with the monomer conversion, the molecular weight distribution being narrow, and a linear relationship existing between ln([M]0/[M]) and the polymerization time. Chain extension polymerization was performed successfully to prepare block copolymer. Furthermore, the azide copolymers were functionalized by CuI‐catalyzed “click” reaction with alkyne‐containing poly(ethylene glycol) (PEG) to yield graft copolymers with hydrophilic PEG side chains. Surface modification of the glass sheet was successfully achieved via the crosslinking reaction of the azide copolymer under UV irradiation at ambient temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1348–1356, 2010
Chain‐growth condensation polymerization of 4‐aminobenzoic acid esters bearing tri(ethylene glycol) side chain with lithium amide base
Authors: Yoshino Kazuo , Hachiman Kotaro , Yokoyama Akihiro , Yokozawa Tsutomu
Published: February 2010

Chain‐growth condensation polymerization of p‐aminobenzoic acid esters 1 bearing a tri(ethylene glycol) monomethyl ether side chain on the nitrogen atom was investigated by using lithium 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) as a base. The methyl ester monomer 1a afforded polymer with low molecular weight and a broad molecular weight distribution, whereas the polymerization of the phenyl ester monomer 1b at −20 °C yielded polymer with controlled molecular weight (Mn = 2800–13,400) and low polydispersity (Mw/Mn = 1.10–1.15). Block copolymerization of 1b and 4‐(octylamino)benzoic acid methyl ester (2) was further investigated. We found that block copolymer of poly1b and poly2 with defined molecular weight and low polydispersity was obtained when the polymerization of 1b was initiated with equimolar LiHMDS at −20 °C and continued at −50 °C, followed by addition of 2 and equimolar LiHMDS at −10 °C. Spherical aggregates were formed when a solution of poly1b in THF was dropped on a glass plate and dried at room temperature, although the block copolymer of poly1b and poly2 did not afford similar aggregates under the same conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1357–1363, 2010
ATRP of methyl methacrylate initiated with a bifunctional initiator bearing bromomethyl functional groups: Synthesis of the block and graft copolymers
Authors: Ozturk Temel , Yilmaz Sevil Savaskan , Hazer Baki , Menceloglu Yusuf Z.
Published: February 2010

This article reports the synthesis of the block and graft copolymers using peroxygen‐containing poly(methyl methacrylate) (poly‐MMA) as a macroinitiator that was prepared from the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in the presence of bis(4,4′‐bromomethyl benzoyl peroxide) (BBP). The effects of reaction temperatures on the ATRP system were studied in detail. Kinetic studies were carried out to investigate controlled ATRP for BBP/CuBr/bpy initiating system with MMA at 40 °C and free radical polymerization of styrene (S) at 80 °C. The plots of ln ([Mo]/[Mt]) versus reaction time are linear, corresponding to first‐order kinetics. Poly‐MMA initiators were used in the bulk polymerization of S to obtain poly (MMA‐b‐S) block copolymers. Poly‐MMA initiators containing undecomposed peroygen groups were used for the graft copolymerization of polybutadiene (PBd) and natural rubber (RSS‐3) to obtain crosslinked poly (MMA‐g‐PBd) and poly(MMA‐g‐RSS‐3) graft copolymers. Swelling ratio values (qv) of the graft copolymers in CHCl3 were calculated. The characterizations of the polymers were achieved by Fourier‐transform infrared spectroscopy (FTIR), 1H‐nuclear magnetic resonance (1H NMR), gel‐permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and the fractional precipitation (γ) techniques. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1364–1373, 2010
Phosphido‐diphosphine pincer group 3 complexes as efficient initiators for lactide polymerization
Authors: Mazzeo Mina , Lamberti Marina , D'Auria Ilaria , Milione Stefano , Peters Jonas C. , Pellecchia Claudio
Published: February 2010

New Group 3 metal complexes of the type [LM(CH2SiMe3)2(THF)n] supported by tridentate phosphido‐diphosphine ligands [(o‐C6H4PR2)2PH; L1‐H: R = iPr; L2‐H: R = Ph] have been synthesized by reaction of L1‐H and L2‐H with [M(CH2SiMe3)3(THF)2)] (M = Y and Sc). All the new complexes [(o‐C6H4PR2)2PM(CH2SiMe3)2(THF)n] [M = Y, R = iPr (1), R = Ph (2); M = Sc, R = iPr (3), R = Ph (4)] were studied as initiators for the ring opening polymerization of lactide. The yttrium complexes (1 and 2) exhibited high activity and good polymerization control, shown by the linear fits in the plot of number‐averaged molecular weight (Mn) versus the percentage conversion and versus the monomer/initiator ratio and by the low polydispersity index values. Interestingly, very good molar‐mass control was observed even when L‐Lactide was polymerized in the absence of solvent at 130 °C. A good molar‐mass control but lower activities were observed in the polymerization reaction of lactide promoted by the analogous scandium complexes 3 and 4. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1374–1382, 2010
A simple methodology for the synthesis of heterotelechelic protein–polymer–biomolecule conjugates
Authors: Liu Jingquan , Liu Huiyun , Bulmus Volga , Tao Lei , Boyer Cyrille , Davis Thomas P.
Published: February 2010

A synthetic protocol for the preparation of hetero‐biofunctional protein–polymer conjugates is described. A chain transfer agent, S,S‐bis (α,α′‐dimethyl‐α″‐acetic acid) trithiocarbonate was functionalized with α,ω‐pyridyl disulfide (PDS) groups, Subsequently, one of the PDS groups was covalently attached to bovine serum albumin (BSA) at the specific free thiol group on the cysteine residue through a disulfide linkage. The second PDS group remained intact, as it was found to be inaccessible to further BSA functionalization. The BSA‐macro‐reversible addition‐fragmentation chain transfer (RAFT) agent was then used to prepare BSA‐polymer conjugates via in situ polymerization of oligo (ethyleneglycol) acrylate and N‐(2‐hydroxypropyl) methacrylamide using an ambient temperature initiator, 4,4′‐azobis [2,9‐imidazolin‐2‐ethyl)propane] dihydrochloride in an aqueous medium. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) confirmed that the in situ polymerization occurred at the protein surface where the RAFT agent was attached and the molecular weights of the BSA–polymer conjugates were found to increase concomitantly with monomer conversion and polymerization time. After polymerization the remaining terminal PDS groups were then utilized to attach thiocholesterol and a flurophore, rhodamine B to the protein–polymer conjugates via disulfide coupling. UV–Vis and fluorescence analyses revealed that ∼80% of the protein conjugates were found to retain integral PDS end groups for further attachment to free thiol‐tethered precursors. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1399–1405, 2010
Synthesis and self‐assembly of rod‐coil molecules with n‐shaped rod building block
Authors: Zhong Ke‐Li , Huang Zhegang , Man Zhijin , Jin Long Yi , Yin Bingzhu , Lee Myongsoo
Published: February 2010

The rod‐coil molecules with n‐shaped rod building block, consisting of an anthracene unit and two biphenyl groups linked together with acetylenyl bonds at the 1,8‐position of anthracene as a rigid rod segment, and the alkyl or alkyloxy chains with various length (i.e., methoxy‐ (1), octyl‐ (2), hexadecyl‐ (3)) at the 10‐position of anthracene and poly(ethylene oxide) with the number of repeating units of 7 connected with biphenyl as coil segments were synthesized. The molecular structures were characterized by 1H NMR and MALDI‐TOF mass spectroscopy. The self‐assembling behavior of new type of molecules 1–3 was investigated by means of DSC, POM, and SAXS at the bulk state. These molecules with a n‐shaped rod building block segment self‐assemble into supramolecular structures through the combination of π–π stacking of rigid rod building blocks and microphase separation of the rod and coil blocks. SAXS studies reveal that molecules 1 and 2 show hexagonal columnar and rectangular columnar structures in the liquid crystalline phase, respectively; meanwhile, molecules 1–3 self‐organize into lamellar structures in the crystalline state. In addition, self‐assembling studies of molecules 1–3 by DLS and TEM indicated that these molecules self‐assemble into elongated nanofibers in aqueous medium. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1415–1422, 2010
Synthesis and characterization of cyclopentadithiophene‐based low bandgap copolymers containing electron‐deficient benzoselenadiazole derivatives for photovoltaic devices
Authors: Jung In Hwan , Kim Hoyeon , Park Moo‐Jin , Kim Bongjun , Park Jong‐Hwa , Jeong Eunjae , Woo Han Young , Yoo Seunghyup , Shim Hong‐Ku
Published: February 2010

We have synthesized two cyclopentadithiophene (CDT)‐based low bandgap copolymers, poly[(4,4‐bis(2‐ethyl‐hexyl)‐4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene‐2,6‐diyl)‐alt‐(benzo[c][1,2,5]selenadiazole‐4,7‐diyl)] (PCBSe) and poly[(4,4‐bis(2‐ethyl‐hexyl)‐4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene‐2,6‐diyl)‐alt‐(4,7‐dithiophen‐2‐yl‐benzo[c][1,2,5]selenadiazole‐5,5′‐diyl)] (PCT2BSe), for use in photovoltaic applications. Through the internal charge transfer interaction between the electron‐donating CDT unit and the electron‐accepting benzoselenadiazole, we realized exceedingly low bandgap polymers with bandgaps of 1.37–1.46 eV. The UV–vis absorption maxima of PCT2BSe were subjected to larger hypsochromic shifts than those of PCBSe, because of the distorted electron donor–acceptor (D–A) structures of the PCT2BSe backbone. These results were supported by the calculations of the D–A complex using the ab initio Hartree‐Fock method with a split‐valence 6‐31G* basis set. However, PCT2BSe exhibited a better molar absorption coefficient in the visible region, which can lead to more efficient absorption of sunlight. As a result, PCT2BSe blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) exhibited a better photovoltaic performance than PCBSe because of the larger spectral overlap integral with respect to the solar spectrum. Furthermore, when the polymers were blended with PC71BM, PCT2BSe showed the best performance, with an open circuit voltage of 0.55 V, a short‐circuit current of 6.63 mA/cm2, and a power conversion efficiency of 1.34% under air mass 1.5 global illumination conditions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1423–1432, 2010
Living cationic polymerization of an azide‐containing vinyl ether toward addressable functionalization of polymers
Authors: Ida Shohei , Ouchi Makoto , Sawamoto Mitsuo
Published: February 2010

We first achieved the living cationic polymerization of azide‐containing monomer, 2‐azidoethyl vinyl ether (AzVE), with SnCl4 as a catalyst (activator) in conjunction with the HCl adduct of a vinyl ether [H‐CH2CH(OR)‐Cl; R  CH2CH2Cl, CH2CH(CH3)2]. Despite the potentially poisoning azide group, the produced polymers possessed controlled molecular weights and fairly narrow distributions (Mw/Mn ∼ 1.2) and gave block polymers with 2‐chloroethyl vinyl ether. The pendent azide groups are easily converted into various functional groups via mild and selective reactions, such as the Staudinger reduction and copper‐catalyzed azide‐alkyne 1,3‐cycloaddition (CuAAC; a “click” reaction). These reactions led to quantitative pendent functionalization into primary amine (NH2), hydroxy (OH), and carboxyl (COOH) groups, at room temperature and without any acidic or basic treatment. Thus, poly(AzVE) is a versatile precursor for a wide variety of functional vinyl ether polymers with well‐defined structures and molecular weights. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1449–1455, 2010
Cocrystallization in ternary blends of ferroelectric copolymers
Authors: Faria Luiz O. , Welter Cezar , Moreira Roberto L.
Published: February 2010

In this work, we report evidences of cocrystallization in ternary blends made of crystalline ferroelectric poly(vinylidene fluoride‐trifluorethylene) [P(VDF‐TrFE)] copolymers. Complete cocrystallization has been unequivocally demonstrated by the observation of just one Curie and one Melting temperature in their calorimetric thermograms. These temperatures were intermediary among the respective temperatures of the individual constituents, that is, P(VDF‐TrFE)72/28, P(VDF‐TrFE)63/37, and P(VDF‐TrFE)50/50. Dielectric and X ray diffraction data were used to complement the investigation. The binary blends made of 63/37 and 72/28 copolymers were found to be miscible in the entire range of composition, with the behavior of their Curie temperatures being well fitted by an equation very similar to that proposed by Gordon‐Taylor to describe the behavior of the glass transition temperatures in true binary blends. In the ternary crystalline system, we have found evidences that the complete miscibility of the binary blend made of 63/37 and 72/28 copolymers actually drives the P(VDF‐TrFE)50/50 copolymer to accommodate their chains in its binary crystalline structure. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 621–626, 2010
Miscibility enhancement and formation of interpenetrating spherulites in ternary blends of crystalline polymers
Authors: Ikehara Takayuki , Kimura Hironori , Kataoka Toshiyuki
Published: February 2010

Miscible blends of three crystalline polymers, namely poly(butylene succinate) (PBS), poly(ethylene succinate) (PES), and poly(oxyethylene) (POE), exhibited interpenetrating spherulites, where a spherulite of one component grows inside the spherulites of other components. PBS and PES were immiscible above the melting points, Tm, of these substances, while ternary blends with POE showed miscibility, which depended on the molecular weight of POE. PBS and PES exhibited the same spherulitic growth process as in a miscible binary blend when they were crystallized from a homogeneous ternary melt. Spherulites of PBS, which is the highest‐Tm component, filled the whole volume first when a miscible ternary blend was quenched below Tm of POE, the lowest‐Tm component. Then, the blends showed either two types of crystallization processes. One was successive nucleation and growth of PES and POE spherulites, that is, PES nucleated and developed spherulites inside the PBS spherulites and then POE spherulites grew inside the interlocked spherulites of PBS and PES. The other was simultaneous growth and the formation of interpenetrating spherulites of PES and POE inside the PBS spherulites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 706–711, 2010
Strain energy function of swollen polybutadiene elastomers studied by general biaxial strain testing
Authors: Bitoh Yohsuke , Akuzawa Norio , Urayama Kenji , Takigawa Toshikazu
Published: February 2010

The stress–strain behavior of polybutadiene elastomers with various degrees of swelling is investigated for general biaxial strain. Although a number of previous observations have suggested that the classical neoHookean (NH) model describes the uniaxial data of an elastomer in a highly swollen state, the NH model evidently fails to reproduce the biaxial data. This result indicates that the successful fit of the NH model for the uniaxial data of highly swollen elastomers, which has long been recognized, is superficial. We show that the biaxial data in all of the various swollen states including the neat (unswollen) state are satisfactorily described by an Ogden‐type strain energy function with a single set of parameters. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 721–728, 2010
Influence of interaction between poly(methyl methacrylate) and clay on the properties of nanocomposites prepared by a heterocoagulation method
Authors: Yang Jintao , Chen Feng , Zhang Fang , Fei Zhengdong , Zhong Mingqiang
Published: February 2010

To have a better insight into the effect of interaction between polymer matrix and clay on the properties of nanocomposite, poly(methyl methacrylate)/clay nanocomposites were prepared by a heterocoagulation method. Using a reactive cationic emulsifier, methacryloyloxyethyltrimethyl ammonium chloride (METAC), a strong polymer–clay interaction was obtained with the advantage of keeping a consistent polymer matrix property. X‐ray diffraction and transmission electronic microscopy indicated an exfoliated structure in nanocomposites. The glass transition temperature (Tg) of the nanocomposites was measured by DSC and DMA. The DMA results showed that with a strong interaction, PMMA–METAC nanocomposite showed a 20 °C enhancement in glass transition temperature (Tg), whereas a slight increase in Tg was observed for PMMA–cetyl trimethylammonium bromide (CTAB)/clay nanocomposite with a weak interaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 733–738, 2010