bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and magnetic properties of novel supramolecular polymeric complexes containing bithiazole rings
Authors: Lin Weihong , Sun Weilin , Yang Jun , Shen Zhiquan 
Published: July 2008

AbstractThe preparation and magnetism of two supramolecular polymeric complexes, DABT/PAA‐Ni2+ and DABT/PAA‐Cu2+, which were obtained via electrostatic interactions of 2,2′‐diamino‐4,4′‐bithiazole (DABT), poly(acrylic acid) (PAA), and transition metal ions (Cu2+ or Ni2+) were described. FTIR, 1H NMR, and elemental analysis were used to characterize the structures of the obtained supramolecular polymer and the corresponding complexes. The corresponding multilayer films were also constructed on the quartz substrate. UV–vis spectra and AFM images were applied to characterize these films. The result indicates a process of uniform assembling. The magnetic behavior was examined as a function of magnetic field strength at 4 K and as a function of temperature (4–300 K). It was found that DABT/PAA‐Ni2+ exhibits a ferromagnetic property with a high value of relative saturation magnetization, while DABT/PAA‐Cu2+ shows a special magnetic property different from the typical magnet. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Nanostructured membranes based on sulfonated poly(aryl ether sulfone) and silica for fuel‐cell applications
Authors: de Carvalho Luisa Magno , Tan Ai Ren , de Souza Gomes Ailton 
Published: July 2008

AbstractNanostructured sulfonated poly(aryl ether sulfone) (SPSU) membranes were made from SPSU/silica composites through the addition of amorphous, precipitated, and micronized silica particles (Tixosil 333) and short or segmented linear structures. Linear and branched segments of silica were obtained from the in situ reaction of tetraethoxysilane (TEOS) in an SPSU solution through a sol–gel acid‐catalyzed process. Different amounts of silica in the SPSU composites were prepared to evaluate their influence on the ionic conductivity, the water and alcohol solution sorption capacities, and the stability in an ethanol medium. The effect of silica (Tixosil) on the conductivity was higher than that of the silica made from TEOS in SPSU composites. The conductivities of the membranes containing 10% Tixosil and 6.6% silica prepared from TEOS were measured at 80°C; their values were 60 and 33 mS/cm, respectively. Furthermore, a membrane made of a silica blend (5% Tixosil and 3% TEOS) in SPSU attained a value of 92 mS/cm, whereas the commercial membrane Nafion 117, used as a reference, had a conductivity of 54 mS/cm measured under the same conditions. All those composites membranes could be used as components in hydrogen fuel cell. However, only the SPSU/2% Tixosil composite could be used in both hydrogen and ethanol direct fuel cells. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Antibacterial effects of a new dental acrylic resin containing silver nanoparticles
Authors: Kassaee M. Z. , Akhavan A. , Sheikh N. , Sodagar A. 
Published: July 2008

AbstractThe addition of silver nanoparticles (Ag NPs) to an acrylic resin rendered a dental composite that exhibited strong antibacterial activity against Escherichia coli and showed rather improved mechanical properties. Such antibacterial effects were mainly attributed to the release of silver ions upon immersion of the composite in water, which appeared to be fairly nontoxic to humans. Furthermore, an acrylic liquid was used as a new reducing agent for the conversion of silver ions into pure elemental Ag NPs in quantitative yields. The structure, morphology, average size, and size distribution of the as‐prepared Ag NPs were determined by scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction, which confirmed the fabrication of rather dispersed, face‐centered cubic nanoparticles with a mean average diameter of 38 nm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Internet information and communication behavior during a political moment: The Iraq war, March 2003
Authors: Robbin Alice , Buente Wayne 
Published: July 2008

AbstractThis article explores the Internet as a resource for political information and communication in March 2003, when American troops were first sent to Iraq, offering us a unique setting of political context, information use, and technology. Employing a national survey conducted by the Pew Internet & American Life project, we examine the political information behavior of the Internet respondents through an exploratory factor analysis; analyze the effects of personal demographic attributes and political attitudes, traditional and new media use, and technology on online behavior through multiple regression analysis; and assess the online political information and communication behavior of supporters and dissenters of the Iraq War. The factor analysis suggests four factors: activism, support, information seeking, and communication. The regression analysis indicates that gender, political attitudes and beliefs, motivation, traditional media consumption, perceptions of bias in the media, and computer experience and use predict online political information behavior, although the effects of these variables differ for the four factors. The information and communication behavior of supporters and dissenters of the Iraq War differed significantly. We conclude with a brief discussion of the value of “interdisciplinary poaching” for advancing the study of Internet information practices.
Hydrogen photoproduction by nutrient‐deprived Chlamydomonas reinhardtii cells immobilized within thin alginate films under aerobic and anaerobic conditions
Authors: Kosourov Sergey N. , Seibert Michael 
Published: July 2008

AbstractA new technique for immobilizing H2‐photoproducing green algae within a thin (<400 µm) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus‐deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 µg Chl mL−1 of matrix), (b) kinetics of H2 photoproduction similar to sulfur‐deprived suspension cultures, (c) higher specific rates (up to 12.5 µmol mg−1 Chl h−1) of H2 evolution, (d) light conversion efficiencies to H2 of over 1% and (e) unexpectedly high resistance of the H2‐photoproducing system to inactivation by atmospheric O2. The algal cells, entrapped in alginate and then placed in vials containing 21% O2 in the headspace, evolved up to 67% of the H2 gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H2‐producing system to inactivation by O2 depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O2 in the liquid and headspace and restrict O2 diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale‐up and possible future applications. Biotechnol. Bioeng. 2008. Biotechnol. Bioeng. 2009;102: 50–58. © 2008 Wiley Periodicals, Inc.
Ionothermal Synthesis of Crystalline, Condensed, Graphitic Carbon Nitride
Authors: Bojdys Michael J. , Müller Jens‐Oliver , Antonietti Markus , Thomas Arne 
Published: July 2008

AbstractHerein we report the synthesis of a crystalline graphitic carbon nitride, or g‐C3N4, obtained from the temperature‐induced condensation of dicyandiamide (NH2C(NH)NHCN) by using a salt melt of lithium chloride and potassium chloride as the solvent. The proposed crystal structure of this g‐C3N4 species is based on sheets of hexagonally arranged s‐heptazine (C6N7) units that are held together by covalent bonds between C and N atoms which are stacked in a graphitic, staggered fashion, as corroborated by powder X‐ray diffractometry and high‐resolution transmission electron microscopy.
Seismic performance of a 3D full‐scale high‐ductility steel–concrete composite moment‐resisting structure—Part I: Design and testing procedure
Authors: Braconi A. , Bursi O. S. , Fabbrocino G. , Salvatore W. , Tremblay R. 
Published: July 2008

AbstractA multi‐level pseudo‐dynamic (PSD) seismic test programme was performed on a full‐scale three‐bay two‐storey steel–concrete composite moment‐resisting frame built with partially encased composite columns and partial‐strength connections. The system was designed to provide strength and ductility for earthquake resistance with energy dissipation located in ductile components of beam‐to‐column joints including flexural yielding of beam end‐plates and shear yielding of the column web panel zone. In addition, the response of the frame depending on the column base yielding was analysed. Firstly, the design of the test structure is presented in the paper, with particular emphasis on the ductile detailing of beam‐to‐column joints. Details of the construction of the test structure and the test set‐up are also given. The paper then provides a description of the non‐linear static and dynamic analytical studies that were carried out to preliminary assess the seismic performance of the test structure and establish a comprehensive multi‐level PSD seismic test programme. The resulting test protocol included the application of a spectrum‐compatible earthquake ground motion scaled to four different peak ground acceleration levels to reproduce an elastic response as well as serviceability, ultimate, and collapse limit state conditions, respectively. Severe damage to the building was finally induced by a cyclic test with stepwise increasing displacement amplitudes. Copyright © 2008 John Wiley & Sons, Ltd.
Real‐time quantitative PCR analysis of pediatric ependymomas identifies novel candidate genes including TPR at 1q25 and CHIBBY at 22q12‐q13
Authors: Karakoula Katherine , Suarez‐Merino Blanca , Ward Samantha , Phipps Kim P. , Harkness William , Hayward Richard , Thompson Dominic , Jacques Thomas S. , Harding Brian , Beck John , Thomas David G. T. , Warr Tracy J. 
Published: July 2008

AbstractLoss of chromosome 22 and gain of 1q are the most frequent genomic aberrations in ependymomas, indicating that genes mapping to these regions are critical in their pathogenesis. Using real‐time quantitative PCR, we measured relative copy numbers of 10 genes mapping to 22q12.3‐q13.33 and 10 genes at 1q21‐32 in a series of 47 pediatric intracranial ependymomas. Loss of one or more of the genes on 22 was detected in 81% of cases, with RAC2 and C22ORF2 at 22q12‐q13.1 being deleted most frequently in 38% and 32% of ependymoma samples, respectively. Combined analysis of quantitative‐PCR with methylation‐specific PCR and bisulphite sequencing revealed a high rate (>60% ependymoma) of transcriptional inactivation of C22ORF2, indicating its potential importance in the development of pediatric ependymomas. Increase of relative copy numbers of at least one gene on 1q were detected in 61% of cases, with TPR at 1q25 displaying relative copy number gains in 38% of cases. Patient age was identified as a significant adverse prognostic factor, as a significantly shorter overall survival time (P = 0.0056) was observed in patients <2 years of age compared with patients who were >2 years of age. Loss of RAC2 at 22q13 or amplification of TPR at 1q25 was significantly associated with shorter overall survival in these younger patients (P = 0.0492 and P = < 0.0001, respectively). This study identifies candidate target genes within 1q and 22q that are potentially important in the pathogenesis of intracranial pediatric ependymomas. © 2008 Wiley‐Liss, Inc.
A pilot study to assess attitudes, behaviors, and inter‐office communication by psychiatrists and primary care providers in the care of older adults with schizophrenia
Authors: Jones Sarah M. , Vahia Ipsit V. , Cohen Carl I. , Hindi Amjad , Nurhussein Mohammed 
Published: July 2008

AbstractIntroductionThere is a lack of assessment tools and empirical data concerning clinician attitudes and behaviors with respect to the health care of older adults with schizophrenia. We develop a survey instrument of physician attitudes, behavior, and inter‐office communication, and provide preliminary data on physician‐related issues in the provision of health care to this population.MethodsA semi‐structured 20‐item survey instrument was administered to a stratified convenience sample of 24 primary care physicians (PCPs) and 27 psychiatrists working in the New York metropolitan area. Using open ended and multiple choice items, scales, summed scores, and case vignettes, we assessed attitudes, experiences, and procedures in treating medical illnesses in older persons with schizophrenia. All scales had internal consistency reliabilities of >0.70.ResultsThere were no differences between PCPs and psychiatrists in reported and anticipated behavior towards older adults with symptoms of schizophrenia, and both groups displayed favorable views. However, both groups had slightly negative stereotypes and attitudes concerning these patients. PCPs reported receiving information from psychiatrists slightly more than 0 to 10 percent of the time.ConclusionsOur preliminary findings indicated more favorable attitudes and behaviors by PCPs than had been anticipated based on earlier research with younger patients. The data suggest that the failure of older schizophrenia patients to receive adequate treatment may not be due primarily to clinicians' negative attitudes and behaviors, and that problems with communication may play a more important role. Copyright © 2008 John Wiley & Sons, Ltd.
Quiescent epithelial cell rests of Malassez can differentiate into ameloblast‐like cells
Authors: Shinmura Yuka , Tsuchiya Shuhei , Hata Ken‐ichiro , Honda Masaki J. 
Published: July 2008

AbstractEpithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. After completion of crown formation, HERS are converted from cervical loop cells, which have the potential to generate enamel for tooth crown formation. Cervical loop cells have the potential to differentiate into ameloblasts. Generally, no new ameloblasts can be generated from HERS, however this study demonstrated that subcultured ERM can differentiate into ameloblast‐like cells and generate enamel‐like tissues in combination with dental pulp cells at the crown formation stage. Porcine ERM were obtained from periodontal ligament tissue by explant culture and were subcultured with non‐serum medium. Thereafter, subcultured ERM were expanded on 3T3‐J2 feeder cell layers until the tenth passage. The in vitro mRNA expression pattern of the subcultured ERM after four passages was found to be different from that of enamel organ epithelial cells and oral gingival epithelial cells after the fourth passage using the same expansion technique. When subcultured ERM were combined with subcultured dental pulp cells, ERM expressed cytokeratin14 and amelogenin proteins in vitro. In addition, subcultured ERM combined with primary dental pulp cells seeded onto scaffolds showed enamel‐like tissues at 8 weeks post‐transplantation. Moreover, positive staining for amelogenin was observed in the enamel‐like tissues, indicating the presence of well‐developed ameloblasts in the implants. These results suggest that ERM can differentiate into ameloblast‐like cells. J. Cell. Physiol. 217: 728–738, 2008. © 2008 Wiley‐Liss, Inc.
Clickable Poly(2‐Oxazoline)s as Versatile Building Blocks
Authors: Fijten Martin W. M. , Haensch Claudia , van Lankvelt Bart M. , Hoogenboom Richard , Schubert Ulrich S. 
Published: July 2008

AbstractCationic ring‐opening polymerization techniques are very sensitive to nucleophiles, which make it difficult to introduce different functional groups into these polymers. Clickable poly(2‐oxazoline)s were synthesized and functionalization was performed by the copper(I)‐catalyzed 1,3‐dipolar cycloaddition between alkynes and azides. Therefore, an alkyne function is introduced into the polymer backbone by utilizing alkyne toluene‐4‐sulfonates as an initiator. The polymerization kinetics were investigated for four different 2‐substituted‐2‐oxazolines and well‐defined acetylene‐functionalized poly(2‐ethyl‐2‐oxazoline)s with different lengths were synthesized having ≈100% functionality. One of these polymers was used to demonstrate its applicability in the azide‐alkyne click reaction by reaction with different azide compounds.magnified image
Influence of clay type on exfoliation, cure and physical properties of in situ polymerised poly(methyl methacrylate) nanocomposites
Authors: Ingram Sharon , Dennis Hugh , Hunter Ian , Liggat John J , McAdam Craig , Pethrick Richard A , Schaschke Carl , Thomson David 
Published: July 2008

AbstractBACKGROUND: The nature of the dispersion of clay platelets in a resin composite will play an important role in the process of enhancement of the physical properties of that material. This paper examines how different modifiers and the quantity of surface treatment for the Cloisite® range of organically modified clays affect properties in in situ polymerised poly(methyl methacrylate). Another clay which is a mixture of rod‐ and platelet‐like minerals is also investigated to understand how the shape of the clay particles can affect the polymer properties.RESULTS: Five different clays, including Cloisite 30B and Cloisite 15A, were dispersed using ultrasound and the cure of the samples was monitored using the Strathclyde Rheometer. Rheology, transmission electron microscopy and X‐ray diffraction were used to determine that a good level of clay dispersion was achieved. The mixed mineral formed the most stable dispersion seen from settling tests.CONCLUSIONS: The cure accelerated in the presence of organoclay, although the affect was less pronounced at higher temperatures. The glass transition temperature was increased by 20 °C with only a few weight percent of clay and water uptake was not adversely affected. Copyright © 2008 Society of Chemical Industry
Photopatternable substrate‐independent poly(glycidyl methacrylate‐ran‐2‐(acryloyloxy) ethyl 2‐methylacrylate) polymer films for immobilization of biomolecules
Authors: Cullen Sean P. , Ha Sangkeun , Lagally Max G. , Gopalan Padma 
Published: July 2008

AbstractWe report the synthesis and characterization of a photocrosslinkable copolymer containing reactive epoxy groups for binding biomolecules. The epoxide‐containing copolymer poly(glycidyl methacrylate‐ran‐2‐(acryloyloxy) ethyl 2‐methylacrylate) offers distinct advantages such as ease of application to various substrates, enhanced stability of the bound oligonucleotide, low autofluorescence, and the ability to be photopatterned allowing localization of the linkers. The copolymer uses pendant acryloyl groups to control the crosslinking without sacrificing the epoxide groups. The films were characterized using ellipsometry, atomic force microscopy, and fluorescence microscopy. The films on glass, silicon wafer, and stainless steel showed no appreciable degradation in water, tetrahydrofuran, and acetone for ∼4 months. The surface topography for a given thickness of crosslinked film was dictated by the deposition conditions. A 16mer oligonucleotide was immobilized on the thin films. A linear relationship between the film thickness and amount of oligonucleotide immobilized was observed with a maximum signal‐to‐background ratio (S/B) of 225 for a 60‐nm‐thick film, a value 50% higher than the S/B for an epoxide monolayer. The crosslinked films maintained a high fluorescence signal following long aqueous washing which is appealing for biological microarrays, immobilizing proteins, and study of slow differentiating cells where stability of the scaffold is relevant. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5826–5838, 2008
Synthesis, pH‐ and temperature‐induced micellization and gelation of doubly hydrophilic triblock copolymer of poly(N,N‐dimethylamino‐2‐ethylmethacrylate)‐b‐poly(ethylene glycol)‐b‐poly(N,N‐dimethylamino‐2‐ethylmethacrylate) in aqueous solutions
Authors: Peng Zhiping , Li Guangzhao , Liu Xinxing , Tong Zhen 
Published: July 2008

AbstractA doubly hydrophilic triblock copolymer of poly(N,N‐dimethylamino‐2‐ethyl methacrylate)‐b‐Poly(ethylene glycol)‐b‐poly(N,N‐dimethylamino‐2‐ethylmethacrylate) (PDMAEMA‐b‐PEG‐b‐PDMAEMA) with well‐defined structure and narrow molecular weight distribution (Mw/Mn = 1.21) was synthesized in aqueous medium via atom transfer radical polymerization (ATRP) of N,N‐dimethylamino‐2‐ethylmethacrylate (DMAEMA) initiated by the PEG macroinitiator. The macroinitiator and triblock copolymer were characterized with 1H NMR and gel permeation chromatography (GPC). Fluorescence spectroscopy, dynamic light scattering (DSL), transmittance measurement, and rheological characterization were applied to investigate pH‐ and temperature‐induced micellization in the dilute solution of 1 mg/mL when pH > 13 and gelation in the concentrated solution of 25 wt % at pH = 14 and temperatures beyond 80 °C. The unimer of Rh = 3.7 ± 0.8 nm coexisted with micelle of Rh = 45.6 ± 6.5 nm at pH 14. Phase separation occurred in dilute aqueous solution of the triblock copolymer of 1 mg/mL at about 50 °C. Large aggregates with Rh = 300–450 nm were formed after phase separation, which became even larger as Rh = 750–1000 nm with increasing temperature. The gelation temperature determined by rheology measurement was about 80 °C at pH 14 for the 25 wt % aqueous solution of the triblock copolymer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5869–5878, 2008
Synthesis, morphology, and properties of hydroxyl terminated‐POSS/polyimide low‐k nanocomposite films
Authors: Wahab Md Abdul , Mya Khine Yi , He Chaobin 
Published: July 2008

AbstractPolyhedral oligomeric silsequioxane (POSS), having eight hydroxyl groups for the preparation of nanocomposites with polyimide (PI) was synthesized by the direct hydrosilylation of allyl alcohol with octasilsesquioxane (Q8M8H) with platinum divinyltetramethyl disiloxane Pt(dvs) as a catalyst. The structure of allyl alcohol terminated‐POSS (POSS‐OH) was confirmed by FTIR, NMR, and XRD. A high performance, low‐k PI nanocomposite from pyromellitic dianhydride (PMDA)‐4,4'‐oxydianiline (ODA) polyamic acid cured with POSS‐OH was also successfully synthesized. The incorporation of POSS‐OH into PI matrix reduced dielectric constant of PI without loosing mechanical properties. Furthermore, the effects of POSS‐OH on the morphology and properties of the PI/POSS‐OH nanocomposites were investigated using UV–vis, FTIR, XRD, SEM, AFM, transmission electron microscope (TEM), TGA, and contact angle. The homogeneous dispersion of POSS particles was confirmed by SEM, AFM, and TEM. The nanoindentation showed that the modulus increased upon increasing the concentration of POSS‐OH in PI, whereas the hardness did not increase very much with respect to loading of POSS, due to soft‐interphase around POSS molecules in the resulting nanocomposites. Overall results demonstrated the nanometer‐level integration of the polymer and POSS‐OH. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5887–5896, 2008