bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of real‐time FT‐IR monitoring of a pharmaceutical compound under stress atmospheric conditions to characterize its solid‐state degradation kinetics
Authors: Skrdla Peter J. , Harrington Chandra , Lin Zhihao 
Published: November 2009

AbstractThe use of online FT‐IR is described for investigating the degradation kinetics of the solid amorphous pharmaceutical compound, fosaprepitant dimeglumine (FD), under stress storage conditions (i.e., high temperature, T, and humidity, % RH). It is found that under conditions of elevated T and % RH, the kinetics are denucleation rate limited for the deliquescence of the amorphous FD solid, based on the high quality fits obtained to the authors' dispersive kinetic model for that mechanism. At elevated T and low % RH, it is found that a classical, first‐order hydrolysis mechanism for the degradation of FD (which forms crystalline aprepitant, AP) significantly contributes to the overall conversion rate. That mechanism is similar to the one observed previously for the solution‐phase hydrolysis of FD. Appropriate kinetic models are proposed for the FD‐to‐AP conversion under all of the experimental conditions investigated in this work. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 25–36, 2010
Surface Modification of Hydroxyapatite Nanoparticles with Thermal‐Responsive PNIPAM by ATRP
Authors: Wei Junchao , He Pan , Liu Aixue , Chen Xuesi , Wang Xianhong , Jing Xiabin 
Published: November 2009

AbstractHydroxyapatite (HA) nanoparticles grafted by poly(N‐isopropylacrylamide) (PNIPAM) brushes (PNIPAM‐g‐HA) have been synthesized by the surface‐initiated atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide (NIPAM). The surface grafting amount of PNIPAM ranges from 15.5% to 46.4%. PNIPAM‐g‐HA has been characterized by FT‐IR spectroscopy, thermal gravimetric analysis, X‐ray diffraction, and scanning electron microscopy (SEM). The UV transmittance spectra and the particle size analysis of PNIPAM‐g‐HA in aqueous solution demonstrates that the PNIPAM‐g‐HA possess reversible thermal stimuli responsive properties. An in vitro bioactivity assessment indicates that PNIPAM‐g‐HA can induce the mineralization of Ca2+ and HPO and possesses an excellent bioactivity. The cell culture results show that the cells adhered to the surface of PNIPAM‐g‐HA grow better than on HA, and the area of the cells on the surface of PNIPAM‐g‐HA is much greater than for HA, which proves that the PNIPAM‐g‐HA has a better biocompatibility than HA.magnified image
Risk factors for poor sleep quality among patients with interstitial cystitis in Taiwan
Authors: Tsai Chia‐Fen , Ouyang Wen‐Chen , Tsai Shih‐Jen , Hong Chen‐Jee , Lin Tong‐Long 
Published: November 2009

AbstractAimsPrevious research has suggested that patients with interstitial cystitis have more sleep disturbances and higher levels of depression. However, reports that employ validated sleep questionnaires are rare for this population. The present study investigates the relationship between sleep quality, anxiety, depression, and the severity of urologic interstitial cystitis symptoms in outpatients, and risk factors for poor sleep quality.MethodsA total of 69 patients (52 female) with interstitial cystitis met National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases (NIDDK) criteria, completed all instruments. The O'Leary‐Sant Interstitial Cystitis Symptom Index (ICSI) was performed to assess interstitial cystitis severity. The Pittsburgh Sleep Quality Index (PSQI) and Hospital Anxiety and Depression Scale (HADS) were used to evaluate quality of sleep and depression level, respectively. Multiple linear regressions were used to identify independent factors of sleep quality.ResultsMean PSQI global score was 9.5 ± 4.2 (range: 1–19); 81.2% of subjects had poor sleep quality (PSQI > 5). Regression analysis suggested that the severity of interstitial cystitis (Beta coefficient = 0.42, P < 0.001) and level of anxiety and depression (Beta coefficient = 0.26, P < 0.05) were significant independent risk factors for poor sleep quality, after controlling for age, gender, marital status, years of education, and years of symptomatic duration. Further analysis of ICSI subdomain scores shows that association between nighttime urination and poor sleep quality remains significantly (Beta coefficient = 0.32, P < 0.05), after adjustment for demographic data and anxiety and depression.ConclusionsPoor sleep quality is common in interstitial cystitis patients and severity of urological symptoms and depression levels are important independent risk factors. Neurourol. Urodynam. 29:568–572, 2010. © 2009 Wiley‐Liss, Inc.
A collocation approach for the numerical solution of certain linear retarded and advanced integrodifferential equations with linear functional arguments
Authors: Gülsu Mustafa , Sezer Mehmet 
Published: November 2009

AbstractThis article presents a Taylor collocation method for the approximate solution of high‐order linear Volterra‐Fredholm integrodifferential equations with linear functional arguments. This method is essentially based on the truncated Taylor series and its matrix representations with collocation points. Some numerical examples, which consist of initial and boundary conditions, are given to show the properties of the technique. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011
Synthesis and nonlinear optical properties of a novel polyurethane containing cyanovinylthiophene with enhanced thermal stability of dipole alignment for electro‐optic applications
Authors: Won Dong‐Seon , Kim Jin‐Hyang , No Hyo Jin , Cho You Jin , Lee Ju‐Yeon , Rhee Bum Ku , Choi Hee‐Dok 
Published: November 2009

AbstractStabilization of electrically induced dipole alignment is one of the important criteria in the development of nonlinear optical (NLO) polymers for electro‐optic device applications. Polyurethanes for NLO applications have attracted attention because of their high thermal stability due to hydrogen bonding. In the work reported here, we designed and synthesized a new type of NLO polyurethane, in which the pendant NLO chromophores are part of the polymer backbone. This mid‐type NLO polymer is expected to have the merits of both main‐chain and side‐chain NLO polymers, namely stable dipole alignment and good solubility. 1‐[3,4‐Di‐(2‐hydroxyethoxy)phenyl]‐2‐(2‐thienyl)ethene was prepared and condensed with 3,3′‐dimethoxy‐4,4′‐biphenylenediisocyanate to yield a polyurethane. This polyurethane was reacted with tetracyanoethylene to give a novel Y‐type polyurethane (7) containing 1‐(3,4‐dioxyphenyl)‐2‐[5‐(1,2,2‐tricyanovinyl)‐2‐thienyl]ethenes as NLO chromophores, which constitute part of the polymer backbone. Polyurethane 7 is soluble in common organic solvents such as N,N‐dimethylformamide and dimethylsulfoxide. It shows a thermal stability up to 280 °C from thermogravimetric analysis with a glass transition temperature obtained from differential scanning calorimetry of ca 162 °C. The second harmonic generation (SHG) coefficient (d33) of a poled polymer film of he polyurethane at 1560 nm fundamental wavelength is ca 1.11 × 10−18 C. Polymer 7 exhibits an enhanced thermal stability and no significant SHG decay is observed below 150 °C, which is acceptable for NLO device applications. Copyright © 2009 Society of Chemical Industry
Electropolymerisation and characterisation of nanosize conducting poly[(o‐chloroaniline)‐co‐(4,4′‐diaminodiphenylsulfone)] on a polyaniline‐modified electrode
Authors: Palaniappan Subramanian , Manisankar Paramasivam 
Published: November 2009

AbstractAn exciting methodology for the electrosynthesis of poly(o‐chloroaniline) is proposed, based on the electrochemical polymerisation of o‐chloroaniline (OCA) on a polyaniline‐modified electrode and copolymerisation of OCA with different compositions of biologically important 4,4′‐diaminodiphenylsulfone (DDS) on the same electrode. The copolymer electrosynthesised from an equimolar feed composition of OCA and DDS behaved the best among the other compositions employed for polymerisation. The UV‐visible and Fourier transform infrared spectral data obtained for this copolymer suggest the incorporation of DDS in the polymer chain. The X‐ray diffraction profile of the copolymer indicates a substantial amorphous nature of the as‐synthesised copolymer. Scanning electron micrographs recorded for the homo‐ and copolymer reveal distinctly different morphologies. The average grain size of the prepared copolymer as approximated from the micrographs is 80 nm. The procedure reported is found to be a very efficient method for electrochemically polymerising pristine OCA and poly(OCA‐co‐DDS) and the adopted strategy is the best so far reported for the electrochemical polymerisation of OCA on any electrode surface. Copyright © 2009 Society of Chemical Industry
Novel modification of polybut‐1‐ene using auto‐oxidation controlled by addition of limonene monomer
Authors: Nakatani Hisayuki , Ichizyu Tadashi , Miura Hiroyuki , Terano Minoru 
Published: November 2009

AbstractFree radical graft polymerization has been used as a modification method to incorporate functional groups into polyolefins using a melt‐mixing process. The presence of oxygen simultaneously brings about auto‐oxidation during the polymerization. Although functional groups such as ketones are easily incorporated into polyolefin chains by auto‐oxidation, the method is rarely employed because of the difficulty of handling. In the study reported here, a novel modification of polybut‐1‐ene (PB) was performed using auto‐oxidation controlled by the addition of limonene monomer. The modified PB samples were prepared using 2,2′‐azobis(2‐methylpropionitrile), benzyl peroxide, tert‐butyl peroxide (TBPO) and Nd2O3/dicumyl peroxide (DCP) radical initiators in air. It was found that excessive auto‐oxidation was suppressed by the presence of the limonene, and that the greatest numbers of grafted groups were contained in the modified PB samples prepared using TBPO and Nd2O3/DCP. The samples obtained showed slower crystallization behavior and slower crystal–crystal transformation rates, respectively. In addition, the modified PB sample prepared using Nd2O3/DCP showed less ductile behavior than that prepared using TBPO because of a much slower transformation rate. Copyright © 2009 Society of Chemical Industry
The phosphoproteome of Fusarium graminearum at the onset of nitrogen starvation
Authors: Rampitsch Christof , Subramaniam Rajagopal , Djuric‐Ciganovic Slavica , Bykova Natalia V. 
Published: November 2009

AbstractFusarium graminearum grown under stress, such as nutrient deprivation, activates, among others, the trichothecene pathway that produces the mycotoxin deoxynivalenol and its derivatives. The kinase inhibitor staurosporine reduced the production of trichothecenes by 39% compared with control in vitro. On the other hand, phosphatase inhibitor okadaic acid increased the amount by 72% compared with the control in vitro. This suggests that phosphorylation events are involved in the signalling pathway, leading to the activation of the trichothecene pathway. Three approaches were used to study the phosphoproteome of F. graminearum under nitrogen‐limiting conditions: 2‐DE (2‐DE: IEF×SDS‐PAGE) in combination with MS protein identification; SDS‐PAGE in combination with off‐line IMAC and TiO2 enrichment and gel electrophoresis LC‐MS analysis; and a gel‐free approach using strong anion exchange chromatography, IMAC and LC‐MS. A total of 348 phosphorylation sites localized in 301 peptides from 241 proteins were identified. By 2‐DE, 20 phosphoproteins were identified, nine of which underwent changes during the time course examined. Using gel electrophoresis LC‐MS 231 phosphopeptides were identified from three samples (ten gel slices each) at time points of nitrogen starvation t=0, 6, and 12 h. The gel‐free analysis added 70 peptides from 65 proteins to the total. Proteins of unknown function and enzymes of known function comprised the largest groups overall. Ten protein kinases and seven transcription factors were identified. This is the first reported phosphoproteome of F. graminearum.
Synthesis of through‐space conjugated polymers containing [2.2]paracyclophane and thieno[3,4‐b]pyrazine in the main chain
Authors: Lin Lin , Morisaki Yasuhiro , Chujo Yoshiki 
Published: November 2009

AbstractWe synthesized through‐space conjugated polymers with [2.2]paracyclophane and thieno[3,4‐b]pyrazine units in the main chain by the Sonogashira–Hagihara coupling reaction. The obtained polymers were soluble in common organic solvents, and homogeneous thin films were readily obtained from the polymer solutions by spin‐coating techniques. The polymers exhibited the extension of the conjugation length via the through‐space interaction. The polymers showed orangish‐red emission with peak maxima of around 610 nm in diluted solutions and their thin films, which were derived from the thieno[3,4‐b]pyrazine moieties. The optical and electrochemical behaviors of the polymers containing pseudo‐para‐ and pseudo‐ortho‐linked [2.2]paracyclophane were identical. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
A degradable, porous, emulsion‐templated polyacrylate
Authors: Lumelsky Yulia , Lalush‐Michael Inbal , Levenberg Shulamit , Silverstein Michael S. 
Published: November 2009

AbstractA polyHIPE is a highly porous, emulsion‐templated polymer synthesized by polymerizing a monomer and a crosslinking comonomer in the continuous phase of a high‐internal phase emulsion (HIPE). The synthesis of degradable polyHIPE could be of interest for biomedical applications such as tissue engineering scaffolds. In this research, a poly(ε‐caprolactone) (PCL) oligomer with terminal vinyl groups was used as the crosslinking comonomer for a polyHIPE based on t‐butyl acrylate (tBA). The porous structure, properties, water absorption, and hydrolytic degradation of the polyHIPE were investigated. The polyHIPE containing 50 wt % PCL exhibited very large voids, 1 to 3 mm in diameter that resulted from the destabilization of the HIPE on addition of PCL, making the polyHIPE more suitable for tissue engineering applications. The relatively flexible PCL enhanced segmental mobility, yielding two glass transition temperatures and a significant reduction in modulus. When exposed to a 3 M aqueous solution of NaOH, the t‐butyl groups underwent hydrolysis and the PCL underwent degradation, rapidly leading to the complete disintegration of the macromolecular structure. The tBA‐based polyHIPE containing 50 wt % PCL exhibited enhanced cell adhesion, penetration, and growth indicating that it is a suitable candidate for further research and development. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Sequential and localized grafting on aliphatic polyester diblock copolymers using alkyne deprotection and click cycloaddition
Authors: Cooper Beth M. , Emrick Todd 
Published: November 2009

AbstractDiblock copolymers, in which both blocks are composed of aliphatic polyesters, were synthesized from two different alkyne‐functionalized δ‐valerolactone monomers by ring opening polymerization and subsequent click cycloaddition. Trimethylsilyl protection of the alkyne functionality of one block was instrumental to the success of the synthesis. These novel aliphatic polyester diblock copolymers were characterized by 1H and 13C NMR spectroscopy, gel permeation chromatography (GPC), and infrared (IR) spectroscopy. Sequential functionalization of the diblock copolymers with hydrophobic groups on one block, and hydrophilic groups on the other block, provides access to amphiphilic structures. Micellar structures generated from these polyester amphiphiles were characterized by fluorescence spectroscopy and transition electron microscopy (TEM). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009
Information‐theoretic analysis of the reference state in contact potentials used for protein structure prediction
Authors: Solis Armando D. , Rackovsky Shalom R. 
Published: November 2009

AbstractUsing information‐theoretic concepts, we examine the role of the reference state, a crucial component of empirical potential functions, in protein fold recognition. We derive an information‐based connection between the probability distribution functions of the reference state and those that characterize the decoy set used in threading. In examining commonly used contact reference states, we find that the quasi‐chemical approximation is informatically superior to other variant models designed to include characteristics of real protein chains, such as finite length and variable amino acid composition from protein to protein. We observe that in these variant models, the total divergence, the operative function that quantifies discrimination, decreases along with threading performance. We find that any amount of nativeness encoded in the reference state model does not significantly improve threading performance. A promising avenue for the development of better potentials is suggested by our information‐theoretic analysis of the action of contact potentials on individual protein sequences. Our results show that contact potentials perform better when the compositional properties of the data set used to derive the score function probabilities are similar to the properties of the sequence of interest. Results also suggest to use only sequences of similar composition in deriving contact potentials, to tailor the contact potential specifically for a test sequence. Proteins 2010. © 2009 Wiley‐Liss, Inc.
At the dawn of the 21st century: Is dynamics the missing link for understanding enzyme catalysis?
Authors: Kamerlin Shina C. L. , Warshel Arieh 
Published: November 2009

AbstractEnzymes play a key role in almost all biological processes, accelerating a variety of metabolic reactions as well as controlling energy transduction, the transcription, and translation of genetic information, and signaling. They possess the remarkable capacity to accelerate reactions by many orders of magnitude compared to their uncatalyzed counterparts, making feasible crucial processes that would otherwise not occur on biologically relevant timescales. Thus, there is broad interest in understanding the catalytic power of enzymes on a molecular level. Several proposals have been put forward to try to explain this phenomenon, and one that has rapidly gained momentum in recent years is the idea that enzyme dynamics somehow contributes to catalysis. This review examines the dynamical proposal in a critical way, considering basically all reasonable definitions, including (but not limited to) such proposed effects as “coupling between conformational and chemical motions,” “landscape searches” and “entropy funnels.” It is shown that none of these proposed effects have been experimentally demonstrated to contribute to catalysis, nor are they supported by consistent theoretical studies. On the other hand, it is clarified that careful simulation studies have excluded most (if not all) dynamical proposals. This review places significant emphasis on clarifying the role of logical definitions of different catalytic proposals, and on the need for a clear formulation in terms of the assumed potential surface and reaction coordinate. Finally, it is pointed out that electrostatic preorganization actually accounts for the observed catalytic effects of enzymes, through the corresponding changes in the activation free energies. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Meta‐analysis of pairs of survival curves under heterogeneity: A Poisson correlated gamma‐frailty approach
Authors: Fiocco M. , Putter H. , van Houwelingen J. C. 
Published: November 2009

AbstractWe address the problem of meta‐analysis of pairs of survival curves under heterogeneity. Starting point for the meta‐analysis is a set of studies, each comparing the same two treatments, containing information about multiple survival outcomes. Under heterogeneity, we model the number of events using an extension of the Poisson correlated gamma‐frailty model with serial within‐arm and positive between‐arm correlations.The parameters of the models are estimated following a two‐stage estimation procedure. In the first stage the underlying hazards and between‐study variance are estimated using the marginals, while a second stage is used to estimate both within‐arm and between‐arm correlations. The methodology is illustrated with an observational study on breast cancer. Copyright © 2009 John Wiley & Sons, Ltd.
Power and sample size calculations for longitudinal studies comparing rates of change with a time‐varying exposure
Authors: Basagaña X. , Spiegelman D. 
Published: November 2009

AbstractExisting study design formulas for longitudinal studies have assumed that the exposure is time‐invariant. We derived sample size formulas for studies comparing rates of change by exposure when the exposure varies with time within a subject, focusing on observational studies where this variation is not controlled by the investigator. Two scenarios are considered, one assuming that the effect of exposure on the response is acute and the other assuming that it is cumulative. We show that accurate calculations can often be obtained by providing the intraclass correlation of exposure and the exposure prevalence at each time point. When comparing rates of change, studies with a time‐varying exposure are, in general, less efficient than studies with a time‐invariant one. We provide a public access program to perform the calculations described in the paper (http://www.hsph.harvard.edu/faculty/spiegelman/optitxs.html). Copyright © 2009 John Wiley & Sons, Ltd.
Stress‐related growth: pre‐intervention correlates and change following a resilience intervention
Authors: Dolbier Christyn L. , Jaggars Shanna Smith , Steinhardt Mary A. 
Published: November 2009

AbstractCorrelates of stress‐related growth and the effectiveness of a resilience intervention to enhance stress‐related growth were examined. College students were randomly assigned to intervention (n = 31) and waiting list control (n = 33) groups. The intervention group received the psychoeducational intervention, Transforming Lives Through Resilience Education, in four weekly 2‐hour sessions. Measures of personal, environmental and stressor characteristics, coping strategies, adjustment and stress‐related growth were assessed. Multiple regressions revealed that pre‐intervention self‐esteem, self‐leadership, hopeful coping and depressive symptoms significantly related to pre‐intervention growth. A repeated measures analysis of variance yielded a significant group by time interaction for total growth; the intervention group showed greater increases in growth pre‐ to post‐intervention compared with the control group. Our results supported the relationships of self‐esteem and adaptive coping strategies to stress‐related growth and introduce a new correlate of growth, self‐leadership, to the literature. In addition, our results highlighted the complex role depressive symptoms may play in relation to growth, indicating that depressive symptoms might decrease one's inner resources while simultaneously serving as a catalyst for growth. Further, the findings supported the resilience intervention as a promising approach to facilitate growth. Copyright © 2009 John Wiley & Sons, Ltd.