bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid response of a poly(acrylamide) hydrogel having a semi‐interpenetrating polymer network structure
Authors: Miyata Takashi , Asami Noriko , Okawa Kaori , Uragami Tadashi 
Published: November 2006

AbstractResponsiveness of a poly(acrylamide) (PAAm) hydrogel having a semi‐interpenetrating polymer network (semi‐IPN) structure was compared with that of a PAAm normal‐type hydrogel in acetone/water mixtures. The PAAm semi‐IPN hydrogel shrank much more rapidly by changes in the acetone concentration than the PAAm normal‐type hydrogel though there was no difference in their equilibrium swelling ratio between them. This suggests that the introduction of a semi‐IPN structure into a hydrogel enhances its responsiveness very easily. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and properties of new phosphorus‐containing poly(ester‐imide)s
Authors: Vlad‐Bubulac Tachita , Hamciuc Corneliu , Petreus Oana , Bruma Maria 
Published: November 2006

AbstractNew phosphorous‐containing poly(ester‐imide)s have been prepared by polycondensation in solution at high temperature of a p‐hydroxyphenol containing phosphorus, namely 2‐(6‐oxid‐6H‐dibenz<c,e><1,2>oxaphosphorin‐6‐yl)‐1,4‐benzenediol, with various aromatic diacide chlorides containing preformed imide rings. The polymers were easily soluble in polar organic solvents, such as N‐methylpyrrolidone, N,N‐dimethylformamide, tetrahydrofuran and chloroform. They showed high thermal stability, the decomposition temperature being above 360°C and the glass transition in the temperature range 142–223°C. One of these polymers exhibited thermotropic liquid crystalline behavior. Solutions of the phosphorous‐containing poly(ester‐imide)s in N,N‐dimethylformamide showed fluorescence having a maximum emission wavelength in the range 376–378 nm. Due to the presence of phosphorus the polymers gave high char yield in thermogravimetric analysis. Copyright © 2006 John Wiley & Sons, Ltd.
Semi‐continuous emulsion copolymerization of vinyl acetate and butyl acrylate using a new protective colloid. Part 2. Effects of monomer ratio and initiator
Authors: Sarac Ayfer , Berber Hale , Yildirim Hüseyin 
Published: November 2006

AbstractPoly(vinyl acetate‐co‐butyl acrylate) latexes with N‐methylol acrylamide were prepared by semi‐continuous emulsion polymerization. The influence of the different initiators and various monomer ratios was studied to relate its physicochemical and colloidal properties. The changes in the copolymer latexes with the use of ammonium persulfate and potassium persulfate initiators were investigated by monitoring viscosity, molecular weights, molecular weight distribution and particle size. It was found that almost all physicochemical and colloidal properties of the latexes followed the same trends for both initiators. Potassium persulfate gave slightly higher results for number‐ and weight‐average molecular weights than ammonium persulfate. Copyright © 2006 John Wiley & Sons, Ltd.
Structural and performance variation of activated carbon‐polymer films
Authors: Ballinas‐Casarrubias L. , Terrazas‐Bandala L. P. , Ibarra‐Gómez R. , Mendoza‐Duarte M. E. , Manjarrez‐Nevárez L. , González‐Sánchez G. 
Published: November 2006

AbstractActivated carbon particles were obtained by a solvatation method and added as fillers in cellulose triacetate as polymeric matrix. Various composite films were prepared by solvent casting at different controlled temperature and relative humidity (35–55° C, 10–70% RH) conditions, for three different filler loadings (0, 1 and 3%). Scanning electron microscopy (SEM) images revealed that for slow solvent evaporation rates (low temperature and high RH) a non‐agglomerated composite film is achieved. This condition observed in SEM was correlated to the film with the best mechanical properties found by stress‐strain and creep tests. Water flux and mechanical resistance is also higher for the membrane obtained at the best synthesis conditions found (M1) (35°C, 70% RH). Contact angle measurements indicated that there is differentiation among membranes of different carbon loading respect to M1, associated to surface homogeneity. Atomic force microscopy (AFM) images showed structural variation among membranes (M1 and its counterpart without carbon) in the nanoscale. Contrast phase AFM analysis exposed homogeneous dispersion of activated carbon particles on membrane M1. Major adhesion between entangled polymer network and activated carbon is postulated as the main factor for the composite polymer proper structural performance. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of responders and reactive domains to rivastigmine in Alzheimer's disease
Authors: Frankfort S. V. , Appels B. A. , de Boer A. , Tulner L. R. , van Campen J. P. C. M. , Koks C. H. W. , Beijnen J. H. , Schmand B. A. 
Published: November 2006

AbstractPurposePresently, it is unclear which patients suffering from Alzheimer's Disease (AD) respond to rivastigmine and if rivastigmine acts on specific cognitive domains. The aims of this study are thus to investigate treatment effects of rivastigmine on specific cognitive domains and to find possible responsive subpopulations to rivastigmine cognitive effects.MethodsMini Mental State Examination (MMSE) and Cambridge Cognitive Examination (CAMCOG) were administered at baseline and after 6 months in 83 rivastigmine users and 96 historical controls, representing natural decline. Treatment effects on different subsections of the CAMCOG and in different subpopulations were investigated by linear regression analyses.ResultsRivastigmine showed effectiveness on total CAMCOG (p < 0.001), CAMCOG non‐memory subsection (p < 0.001) and subscales of language (p = 0.002), attention/calculation (p = 0.043), abstract thinking (p < 0.001) and perception (p = 0.031). In patients with baseline MMSE ≤19 rivastigmine showed significant and favourable effects compared to historical controls on total CAMCOG (p < 0.001) and both non‐memory (p < 0.001) and memory subsections (p = 0.002).ConclusionRivastigmine showed primarily effectiveness on the non‐memory section of the CAMCOG and patients with a baseline MMSE ≤ 19 appeared to show greater responses to rivastigmine compared to patients with baseline MMSE ≥ 20. Copyright © 2006 John Wiley & Sons, Ltd.
Brownian dynamics simulation of polyelectrolyte dilute solutions under shear flow
Authors: Pamies R. , Cifre J.G. Hernández , De La Torre J. García 
Published: November 2006

AbstractThe behavior of dilute solutions of linear polyelectrolyte molecules both at equilibrium and under shear flow is modeled by using the Brownian dynamics simulation technique. The mathematical polymer model consists of a bead‐and‐spring chain with charged beads that interact through a screened Debye–Hückel potential as well as through FENE spring forces. In addition hydrodynamic interaction is included in the simulations. We also illustrate how to parameterize a real polyelectrolyte chain, using as an example the often studied sodium polystyrene sulfonate. This gives us an estimate of the values of the model parameters to be used in the simulations. The dependence of conformational and hydrodynamic properties on salt concentration (parameterized through the Debye length) and on electrostatic strength (related to the degree of ionization) is studied. It is found that the model describes many of the features of polyelectrolyte dilute solutions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1–9, 2007
What to do when ‘there is nothing more to do’? A study within a salutogenic framework of family members' experience of palliative home care staff
Authors: Milberg A. , Strang P. 
Published: November 2006

AbstractThe aim of this study was to develop a theoretical framework of family members' experience of palliative home care staff based on a secondary analysis of four previous studies. A salutogenic framework was used, i.e. with the origin of health in focus. Data had been collected (semi‐structured tape‐recorded interviews and postal questionnaires with open‐ended questions) from 469 family members of mainly cancer patients referred to advanced palliative home care. Walker and Avant's strategies for theory construction were used. The secondary analysis generated three theoretical blocks: (1) general components of staff input (including five generalized resistance resources (GRRs): competence, support, spectrum of services, continuity, and accessibility); (2) specific interactions with staff (including two GRRs: being in the centre and sharing caring); (3) emotional and existential consequences of staff support (including six health‐disease continuums: security‐insecurity, hope–hopelessness, congruent inner reality‐chaos, togetherness‐isolation, self‐transcendence‐feelings of insufficiency and retained everyday life‐disrupted everyday life). It seems important that all three aspects of family members' experience of palliative care staff are to be considered in evaluations of palliative care, in goal‐setting and in teaching role models. The study is specific to the Swedish model of palliative home care and replication of the work in other countries is recommended. Copyright © 2006 John Wiley & Sons, Ltd.
Disease severity, mental health, and quality of life of children and adolescents with asthma
Authors: Goldbeck Lutz , Koffmane Katja , Lecheler Josef , Thiessen Kai , Fegert Jörg M. 
Published: November 2006

AbstractAsthma has been found related to a higher risk of psychological problems. Inconsistent results have been reported with respect to the quality of life of children with asthma. So there may be a complex relationship between asthma severity, quality of life, and psychological factors. The aim of this study was to examine the impact of asthma severity and emotional/behavioral problems on the quality of life of children and adolescents and on their need for support.Eighty‐one children and adolescents (7–18 years old, 62 boys, 19 girls) with asthma participating in different intervention and rehabilitation programs completed the Ulm Inventory for Children, an instrument for assessing health‐related quality of life. Psychological problems were rated using the Child Behavior Checklist (CBCL). Caregivers judged the patients' need for support due to asthma and due to psychosocial problems. Asthma severity was rated according to the GINA classification.The participants showed elevated caregiver‐reported emotional and behavioral symptoms compared with the normative sample (mean CBCL total score T = 63). Quality of life and the need for social support were significantly correlated with psychological symptoms. Asthma severity was neither correlated with quality of life nor with emotional/behavioral symptoms, but it was associated with the need for support due to asthma.Therefore, in our study, comorbid emotional and behavioral symptoms rather than disease severity predicted quality of life of children and adolescents with asthma. Treatment should be adjusted to the special needs of children with asthma and comorbid mental health problems. Pediatr Pulmonol. 2007; 42:15–22. © 2006 Wiley‐Liss, Inc.
Learning about protein hydrogen bonding by minimizing contrastive divergence
Authors: Podtelezhnikov Alexei A. , Ghahramani Zoubin , Wild David L. 
Published: November 2006

AbstractDefining the strength and geometry of hydrogen bonds in protein structures has been a challenging task since early days of structural biology. In this article, we apply a novel statistical machine learning technique, known as contrastive divergence, to efficiently estimate both the hydrogen bond strength and the geometric characteristics of strong interpeptide backbone hydrogen bonds, from a dataset of structures representing a variety of different protein folds. Despite the simplifying assumptions of the interatomic energy terms used, we determine the strength of these hydrogen bonds to be between 1.1 and 1.5 kcal/mol, in good agreement with earlier experimental estimates. The geometry of these strong backbone hydrogen bonds features an almost linear arrangement of all four atoms involved in hydrogen bond formation. We estimate that about a quarter of all hydrogen bond donors and acceptors participate in these strong interpeptide hydrogen bonds. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Enhanced degradation of atrazine under field conditions correlates with a loss of weed control in the glasshouse
Authors: Krutz L Jason , Zablotowicz Robert M , Reddy Krishna N , Koger III Clifford H , Weaver Mark A 
Published: November 2006

AbstractEnhanced degradation of atrazine has been reported in the literature, indicating the potential for reduced residual weed control with this herbicide. Experiments were conducted to determine the field dissipation of atrazine in three cropping systems: continuous Zea mays L. (CC) receiving atrazine applications each year, Gossypium hirsutum L.–Z. mays rotation (CCR) receiving applications of atrazine once every 2 years and a no atrazine history soil (NAH). Subsequent laboratory and greenhouse experiments were conducted with soil collected from these cropping systems to determine atrazine degradation, mineralization and residual weed control. Field dissipation of atrazine followed first‐order kinetics, and calculated half‐life values for atrazine combined over 2003 and 2005 increased in the order of CC (9 d) = CCR (10 d) < NAH (17 d). Greenhouse studies confirmed that the persistence of atrazine was approximately twofold greater in NAH soil than in CC or CCR soil. Biometer flask mineralization studies suggested that enhanced degradation of atrazine was due to rapid catabolism of the s‐triazine ring. Glasshouse efficacy studies revealed a loss of residual weed control in CC and CCR soil compared with NAH soil. These data indicate that, under typical Mississippi Delta field conditions and agronomic practices, the persistence of atrazine may be reduced by at least 50% if the herbicide is applied more than once every 24 months. Glasshouse studies suggest that under these conditions a loss of residual weed control is possible. Published in 2006 by John Wiley & Sons, Ltd
ESR study of La1–xPbxMnO3 (0.1 ≤ x ≤ 0.5) perovskites
Authors: Phan T. L. , Min S. G. , Phan M. H. , Ha N. D. , Chau N. , Yu S. C. 
Published: November 2006

AbstractElectron spin resonance (ESR) spectra of La1–x Pbx MnO3 (0.1 ≤ x ≤ 0.5) compounds were recorded at different temperatures. Asymmetrical and distored resonance signals due to ferromagnetic correlations at temperatures T < Tmin became Lorentzian at T > Tmin, where Tmin is the temperature corresponding to the narrowest ESR linewidth. The ESR linewidth with respect to temperature, ΔH (T), for the samples was fitted to the one‐phonon process, ΔH (T) = A + BT. We found that B decreased from 5.45 Oe/K for x = 0.1 to 4.61 Oe/K for x = 0.5, indicating the decrease of lattice distortions with the Pb addition. The tem‐ perature dependence of the ESR intensity, I (T), for the samples was described well to an expression of I (T) = I0 exp (Ea/kBT). In the high‐temperature region, 1/I (T) obeyed the Curie–Weiss law. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Natural products as alternative treatments for metabolic bone disorders and for maintenance of bone health
Authors: Putnam Sophie E. , Scutt Andy M. , Bicknell Katrina , Priestley Caroline M. , Williamson Elizabeth M. 
Published: November 2006

AbstractBone metabolism involves a complex balance between the deposition of matrix and mineralization and resorption. There is now good evidence that dietary components and herbal products can influence these processes, particularly by inhibiting bone resorption, thus having beneficial effects on the skeleton. For example, it has been reported that a number of common vegetables, including onion, garlic and parsley, can inhibit bone resorption in ovariectomized rats. Essential oils derived from sage, rosemary, thyme and other herbs inhibit osteoclast activity in vitro and in vitro and leading to an increase in bone mineral density. Soya, a rich source of isoflavones, has shown promising results and epidemiological evidence to support a use in maintaining bone health, and various traditional herbal formulae in Chinese and Ayurvedic medicine also have demonstrable effects in pharmacological models of osteoporosis. Recently, cannabinoids have been described as having positive effects on osteoblast differentiation, and the presence of cannabinoid receptors in bone tissue indicates a more complex role in bone metabolism than previously thought. The first part of this review briefly discusses normal bone metabolism and disorders caused by its disruption, with particular reference to osteoporosis and current pharmacological treatments. The effects of natural products on bone and connective tissue are then discussed, to include items of diet, herbal extracts and food supplements, with evidence for their efficacy outlined. Copyright © 2006 John Wiley & Sons, Ltd.
Similarity Metrics and Descriptor Spaces – Which Combinations to Choose?
Authors: Glen Robert C. , Adams Samuel E. 
Published: November 2006

AbstractMolecular similarity is widely used in virtual screening. There are a very large number of possible combinations of molecular descriptors and analysis methods that can be combined to pre‐select compounds. The objectives strongly influence the methods chosen, in particular whether the desired outcome is to design a diverse library for initial screening; to follow up with additional similar hits (to perhaps help in establishing SAR) or to discover novel scaffolds (lead hopping) with the objective of obtaining novel patentable series (perhaps with different pharmacokinetics). Some of the factors that influence these decisions are discussed along with applications that compare and contrast methods and their performance in different situations.
Time‐Series QSAR Analysis of Human Plasma Protein Binding Data
Authors: Rodgers Sarah L. , Davis Andrew M. , van de Waterbeemd Han 
Published: November 2006

AbstractQuantitative Structure–Activity Relationship (QSAR) models are built using a wide variety of methods and descriptors in order to produce the optimal model for a given property or activity. Once built, models tend to be static or very rarely updated, yet chemistry progresses with time. Any QSAR model is limited by the data used to create it, which in turn is dependent on the data available at the time of building. This study investigates the time dependence of the predictive ability of QSAR models. This is achieved by examining the performance of a human plasma protein binding model over time. A number of QSAR models were built using Partial Least‐Squares (PLS) and tested using data collected from experiments conducted at specific time points over a two‐year period. The ability of these updated models to make predictions was compared with that of a model built with data from the beginning of the time period. In general, the updated models are stable over time and predictions vary only to a small degree from one model to the next. However, for both current and future test data, the updated models are overall more effective at making predictions than the static model. This highlights the benefits of using more current data for making predictions and thus the need for autoupdating QSAR models.
Ab initio study on the reaction mechanism of ozone with bromine atom
Authors: Bing Dan , Zhao Yongfang , Hao Fengyou , Li Xinying , Liu Fengli , Zhang Guohua , Zhang Pingxia 
Published: November 2006

AbstractAb initio calculations of the potential energy surface (PES) for the Br+O3 reaction have been performed using the MP2, CCSD(T), and QCISD(T) methods with 6‐31G(d), 6‐311G(d), and 6‐311+G(3df). The reaction begins with a transition state (TS) when the Br atom attacks a terminal oxygen of ozone, producing an intermediate, the bromine trioxide (M), which immediately dissociates to BrO+O2. The geometry optimizations of the reactants, products, and intermediate and transition states are carried out at the MP2/6‐31G(d) level. The reaction potential barrier is 3.09 kcal/mol at the CCSD(T)/6‐311+G(3df)//MP2 level, which shows that the bromine atom trends intensively to react with the ozone. The comparison of the Br+O3 reaction with the F+O3 and Cl+O3 reactions indicates that the reactions of ozone with the halogen atoms have the similar reaction mechanism. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Conformational analysis for some nonclassical antagonists of histamine H3 receptor
Authors: Borota Ana , Mracec Maria , Rad Ramona , Ostopovici Liliana , Mracec Mircea 
Published: November 2006

AbstractA conformational search in vacuum for a series of 1,3‐substituted pyrrolidine derivatives has been performed using the AMBER, AM1, PM3, and MNDO methods. Conformational analysis of the pyrrolidine ligands suggests that these compounds could have many conformers that populate the low‐energy minima on the potential energy surface (PES). The conformational space occupied by the ligands is large and, in vacuum, the rotation barriers of different flexible bonds have energies between 0.5 and thousands of kcal/mol. By optimization, most conformers have energy barriers of 0–5 kcal/mol; thus, they could interconvert easily to obtain better interactions in the receptor active site. Optimized conformers having energy barriers of >5 kcal/mol display bad geometries with very large bond lengths and deformed rings. Shapes and heights of rotation barriers obtained through COSMO–AM1 single‐point calculations in water are similar to those obtained from single‐point calculations in vacuum. However, in water the energy barriers are lower, allowing most conformers to convert in other low‐energy conformers. The best conformers in vacuum and in water are different: the gas phase best conformer has a helical shape, while the best conformer in water has an extended shape. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Minimum proton affinity for efficient ionization with atmospheric pressure desorption/ionization on silicon mass spectrometry
Authors: Östman Pekka , Pakarinen Jaana M. H. , Vainiotalo Pirjo , Franssila Sami , Kostiainen Risto , Kotiaho Tapio 
Published: November 2006

AbstractWe performed a systematic study using a set of compounds with different proton affinities (PAs) on the ionization in atmospheric pressure desorption/ionization on silicon mass spectrometry (AP‐DIOS‐MS). The compounds studied included various aromatic molecules of different sizes. The PAs of these compounds were calculated using ab initio and hybrid density functional theory calculations at the B3LYP/6‐31G(d) level of theory. We observed that only compounds with relatively high PAs above a threshold value of 920–950 kJ/mol were efficiently ionized as protonated molecules under AP‐DIOS conditions and produced very clean mass spectra. Copyright © 2006 John Wiley & Sons, Ltd.