bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlling Thermochromism in a Photonic Block Copolymer Gel
Authors: Walish Joseph J. , Fan Yin , Centrone Andrea , Thomas Edwin L. 
Published: July 2012

AbstractThe tunable properties of stimulus‐responsive materials attract great interest in a variety of technological applications. Photonic gels are a new class of these materials, which can be tuned to reflect different wavelengths of light. Controlling this reflected color via temperature‐induced changes of self‐assembled photonic materials is important for their application in sensors and displays. In this work, the thermochromic behavior of a PS–P2VP photonic gel was found to originate from a temperature‐induced change in the pKa of the P2VP blocks. Control was obtained through the manipulation of the solution pH. The findings of this work provide the basis for understanding and controlling the properties of thermochromic block copolymers fostering their use in technologically relevant applications.
Semiflexibility Highlights the Polymers' Topology: Monte Carlo Studies
Authors: Berezovska Ganna , Dolgushev Maxim , Blumen Alexander 
Published: July 2012

AbstractSummary: In this article we analyze in how far semiflexible behavior enhances the differences in the properties of classes of polymers whose topological structure varies. We focus on three pairs of macromolecular classes: stars vs. chains, unknotted rings vs. rings with one knot (trefoils), and stars vs. unknotted rings. For this we determine the mean‐square radii of gyration and the bond‐bond correlation functions through Monte Carlo simulations which use the bond fluctuation model. We show that introducing semiflexibility magnifies the differences between experimentally measurable quantities and may even lead to qualitative changes. Our simulation results are supported by theoretical studies which make use of the maximum entropy principle.
Synthesis and Solution Properties of Loose Polymer Brushes Having Polyimide Backbone and Methylmethacrylate Side Chains
Authors: Krasova Anna , Belyaeva Elena , Tarabukina Elena , Filippov Alexander , Meleshko Tamara , Ilgach Dmitry , Bogorad Natalia , Yakimansky Alexander 
Published: July 2012

AbstractSummary: Graft‐copolymers with polyimide backbone and PMMA side chains are synthesized by ATRP of methylmethacrylate on the polyimide macroinitiator. The obtained copolymers, macroinitiator, and cleaved side chains are investigated by 1H NMR, SEC, static and dynamic light scattering, sedimentation, and viscosimetry in solutions. The synthesized copolymer is relatively loose polymer brushes: the average distance between grafted PMMA chains is ∼11 nm (4 repeat units of the backbone). The hydrodynamic and conformational characteristics of graft‐copolymers change on passage from ethylacetate to chloroform due to difference in the thermodynamic quality of the solvents with respect to the copolymer components. The backbone is characterized more extended conformation than individual polyimide macromolecule.
Thermostable Polycyanurate‐Polyhedral Oligomeric Silsesquioxane Hybrid Networks: Synthesis, Dynamics and Thermal Behavior
Authors: Starostenko Olga , Bershtein Vladimir , Fainleib Alexander , Egorova Larisa , Grigoryeva Olga , Sinani Alfred , Yakushev Pavel 
Published: July 2012

AbstractSummary: A series of hybrid polycyanurate ‐ epoxy cyclohexyl‐functionalized polyhedral oligomeric silsesquioxane (PCN/ECH‐POSS) nanocomposite networks with ECH‐POSS content varying from 0.025 to 10 wt. % were synthesized and characterized using FTIR, DSC, DMA and CRS techniques. It was revealed that already as low as 0.025 wt. % POSS cardinally changed PCN glass transition characteristics including the strong shift of the transition onset to higher temperatures and manifesting a second, higher‐temperature glass transition characterizing interfacial dynamics; additionally, enhancing creep resistance and thermal stability at the earlier stage of degradation were observed.
Advances in the Prediction of Turn Structures in Peptides and Proteins
Authors: Koch Oliver 
Published: July 2012

AbstractTurns are essential for protein structure as they allow the polypeptide chain to fold backup on itself. They also occur within protein binding sites, at proteinprotein interfaces and in small bioactive peptides, where they can play a crucial role for molecular recognition. Turn structures are an important class of protein secondary structure, although relatively little attention is paid to them with respect to helices and β‐sheets. Protein structure prediction, functional analysis of proteins and peptides, and computer‐aided drug design could all benefit from making use of accurately predicted turn structures from amino acid sequence. Here, recent advances of turn structure prediction and the underlying turn classification will be discussed together with their applications.
Polyphenol‐rich foods exhibit DNA antioxidative properties and protect the glutathione system in healthy subjects
Authors: Pedret Anna , Valls Rosa M. , Fernández‐Castillejo Sara , Catalán Úrsula , Romeu Marta , Giralt Montserrat , Lamuela‐Raventós Rosa M. , Medina‐Remón Alexander , Arija Victoria , Aranda Núria , Espinel Alberto , Delgado Marco Antonio , Solà Rosa 
Published: July 2012

ScopePolyphenols (ingested via food items) can decrease DNA, and oxidative damage of proteins and lipids. However, polyphenol effects in healthy populations have not been well defined. The aim of this study was to assess the relationship between urinary total polyphenol excretion (TPE), a biomarker of total polyphenol intake (TPI), polyphenol‐rich foods, and oxidative stress biomarkers in healthy adults of different ages participating in the cross‐sectional PAScual MEDicina study.Methods and resultsUrinary TPE was determined by Folin–Ciocalteau method in spot urine samples of 81 participants (46 women), classified into three age groups: 18 to 39, 40 to 54, and 55 to 72 years of age. TPI was quantified from 3‐day dietary records using the Phenol‐Explorer database. Urinary TPE increased with age (p < 0.001). Urinary TPE was inversely associated with urinary 8‐hydroxydeoxyguanosine (8‐OHdG; p<0.001) and erythrocyte‐oxidized glutathione concentrations (p < 0.05). A negative association between urinary 8‐OHdG and daily intake of polyphenols from vegetables and fermented beverages such as red wine was observed.ConclusionUrinary TPE increased with age and may reflect attenuation of oxidative damage. These results could explain the beneficial effects in healthy individuals of a diet rich in vegetables and moderate red wine; food items typical of the Mediterranean diet.
Suboptimal dietary zinc intake promotes vascular inflammation and atherogenesis in a mouse model of atherosclerosis
Authors: Beattie John H. , Gordon Margaret‐Jane , Duthie Susan J. , McNeil Chris J. , Horgan Graham W. , Nixon Graeme F. , Feldmann Jörg , Kwun In‐Sook 
Published: July 2012

ScopeCardiovascular health is strongly influenced by diet. Zinc has antioxidant and anti‐inflammatory properties but its long‐term influence on vascular health at dietary intake levels relevant to the human population in developed countries has not been studied. We investigated the influence of suboptimal zinc intake in a Western‐type diet on the development of vascular inflammation and arterial plaque in apoE knock‐out (AEKO) mice.Methods and resultsWeanling AEKO and wild‐type (WT) controls were given high saturated fat (21% w/w) and high cholesterol (0.15%) semi‐synthetic diets containing 3 or 35 mg Zn/kg (AEKO and WT) or 8 mg Zn/kg (AEKO only) for over 6 months. AEKO mice on zinc intakes of 3 and 8 mg Zn/kg (suboptimal zinc) developed significantly (p < 0.05) more aortic plaque than AEKO mice consuming 35 mg Zn/kg (adequate zinc). Circulating levels of interleukin‐1β, interleukin‐6 and soluble vascular adhesion molecule‐1 were significantly (p < 0.05) raised at the lowest zinc intake in AEKO mice, as compared to zinc‐adequate controls. Plasma total cholesterol and total protein were also significantly (p < 0.05) increased at the lowest zinc intake.ConclusionWe propose that suboptimal dietary zinc intake raises circulating pro‐atherogenic lipoprotein levels that promote vascular inflammation and enhance arterial plaque formation.
7Li+ NMR quadrupolar splitting in stretched hydrogels: developments in relaxation time estimation from z‐spectra
Authors: Puckeridge Max , Chapman Bogdan E. , Kuchel Philip W. 
Published: July 2012

ABSTRACT7Li NMR z‐spectra were recorded from the cation constituted in gelatin gels that were held stretched. The system has been studied previously, but we revisited the disparity that was noted between estimates of some of the relaxation times of spin‐states of various ranks and orders made using a global data‐fitting strategy and estimates made from data acquired by using multiple‐quantum‐filter pulse sequences. The global data fitting was performed with a probability approach along with the Markov chain Monte Carlo (MCMC) method applied to z‐spectra from 7Li+ dissolved in 1H2O using more refined experimental methods than hitherto. We also present a more extensive explanation of the MCMC method as it applies in the present NMR context. We achieved much closer agreement between the estimates of relaxation times made by using the two methods of analysis and attribute the previous discrepancies to spectral drift and z‐spectrum asymmetry. Copyright © 2012 John Wiley & Sons, Ltd.
Vanadium‐Modified Bimetallic Phillips Catalyst With High Branching Ability for Ethylene Polymerization
Authors: Matta Akanksha , Zeng Yanning , Taniike Toshiaki , Terano Minoru 
Published: July 2012

AbstractIn order to improve the branching ability of Phillips catalyst for ethylene polymerization, a new bimetallic Phillips catalyst was developed. In this work, a series of vanadium‐modified Phillips catalyst were prepared through co‐impregnation by varying the pH of the impregnation solution, the vanadium loading and the vanadium precursors. A method to prepare bimetallic Phillips catalyst having good catalytic performance was proposed. Catalyst characterization by diffuse reflectance UV‐Vis and X‐ray photoelectron spectroscopies clarified the key role of specific interaction between chromium and vanadium components for the improvements in branching ability and catalyst activity.magnified image
Intrazelluläre Elektronenspinresonanz‐Spektroskopie
Authors: Drescher Malte 
Published: July 2012

AbstractMethoden zur Aufklärung nativer Konformationen biologischer Makromoleküle in lebenden Zellen sind sehr gefragt — und rar. Jüngste methodische Entwicklungen erlauben jetzt intrazelluläre Abstandsmessungen mit Elektronenspinresonanz‐Spektroskopie.
Das Chemieinstitut auf der Alb
Authors: Lässing Volker 
Published: July 2012

AbstractIn diesem Jahr feiert das Max‐Planck‐Institut für Chemie in Mainz seinen hundertsten Geburtstag, denn am 23. Oktober 1912 öffnete es als Kaiser‐Wilhelm‐Institut für Chemie in Berlin‐Dahlem seine Türen. Neben Berlin und Mainz existierte das Institut aber noch sechs Jahre an einem dritten Standort: in der kleinen Stadt Tailfingen auf der Schwäbischen Alb.
Solution of the time‐harmonic viscoelastic inverse problem with interior data in two dimensions
Authors: Zhang Yixiao , Oberai Assad A , Barbone Paul E , Harari Isaac 
Published: July 2012

SUMMARYWe consider the problem of determining the distribution of the complex‐valued shear modulus for an incompressible linear viscoelastic material undergoing infinitesimal time‐harmonic deformation, given the knowledge of the displacement field in its interior. In particular, we focus on the two‐dimensional problems of anti‐plane shear and plane stress. These problems are motivated by applications in biomechanical imaging, where the material modulus distributions are used to detect and/or diagnose cancerous tumors. We analyze the well‐posedness of the strong form of these problems and conclude that for the solution to exist, the measured displacement field is required to satisfy rather restrictive compatibility conditions. We propose a weak, or a variational formulation, and prove the existence and uniqueness of solutions under milder conditions on measured data. This formulation is derived by weighting the original PDE for the shear modulus by the adjoint operator acting on the complex‐conjugate of the weighting functions. For this reason, we refer to it as the complex adjoint weighted equation (CAWE). We consider a straightforward finite element discretization of these equations with total variation regularization, and test its performance with synthetically generated and experimentally measured data. We find that the CAWE method is, in general, less diffusive than a corresponding least squares solution, and that the total variation regularization significantly improves its performance in the presence of noise. Copyright © 2012 John Wiley & Sons, Ltd.
An optimal versatile partial hybrid stress solid‐shell element for the analysis of multilayer composites
Authors: Rah K. , Van Paepegem W. , Degrieck J. 
Published: July 2012

SUMMARYIn the present contribution we propose an optimal low‐order versatile partial hybrid stress solid‐shell element that can be readily employed for a wide range of geometrically linear elastic structural analyses, that is, from shell‐like isotropic structures to multilayer anisotropic composites. This solid‐shell element has eight nodes with only displacement degrees of freedom and only a few internal parameters that provide the locking‐free behavior and accurate interlaminar shear stress resolution through the element thickness. These elements can be stacked on top of each other to model multilayer composite structures, fulfilling the interlaminar shear stress continuity at the interlayer surfaces and zero traction conditions on the top and bottom surfaces of composite laminates. The element formulation is based on the modified form of the well‐known Fraeijs de Veubeke–Hu–Washizu multifield variational principle with enhanced assumed strains formulation and assumed natural strains formulation to alleviate the different types of locking phenomena in solid‐shell elements. The distinct feature of the present formulation is its ability to accurately calculate the interlaminar shear stress field in multilayer structures, which is achieved by the introduction of the assumed interlaminar shear stress field in a standard enhanced assumed strains formulation based on the Fraeijs de Veubeke–Hu–Washizu principle. The numerical testing of the present formulation, employing a variety of popular numerical benchmark examples related to element patch test, convergence, mesh distortion, shell and laminated composite analyses, proves its accuracy for a wide range of structural analyses.Copyright © 2012 John Wiley & Sons, Ltd.
Surface Dynamics of SiO2‐like Films on Polymers Grown by DBD Assisted CVD at Atmospheric Pressure
Authors: Premkumar Peter Antony , Starostin Sergey A. , de Vries Hindrik , Creatore Mariadriana , Koenraad Paul M. , MacDonald William A. , van de Sanden Mauritius C. M. 
Published: July 2012

AbstractThe development of the morphology and surface roughness of amorphous SiO2‐like films, on various polymeric substrates was analyzed by atomic force microscopy. The inorganic oxide films were deposited from organo‐silicon precursors with different reactive gases using dielectric barrier discharge assisted chemical vapor deposition (DBD‐CVD) at atmospheric pressure in a roll‐to‐roll configuration. Detailed study on the roughness statistical parameters characterizing morphology shows that DBD‐CVD films grow in a conformal and layer‐by‐layer like fashion on polymers very similar to films produced by atomic layer deposition process. Independent of substrate (planarised and non‐planarised polyethylene‐2,6‐napthalate) and methodology used to build the thickness as stacks or single layers, the films were found to be smooth, both locally and globally, and show negligible development of roughness with thickness (≤350 nm). The scaling exponents observed, show that the film growth does not fall into any of the universality classes that have been reported so far.magnified image
Plasma Polymerization of Acrylic Acid by Atmospheric Pressure Nitrogen Plasma Jet for Biomedical Applications
Authors: Carton Olivier , Ben Salem Dhia , Bhatt Sudhir , Pulpytel Jérôme , Arefi‐Khonsari Farzaneh 
Published: July 2012

AbstractPolyacrylic acid thin films have been deposited by an original and fast technique to grow organic coatings: a pulsed‐arc atmospheric pressure plasma jet. Liquid acrylic acid was introduced in the nitrogen plasma jet and OES was used to measure the fragmentation of the precursor. The films were characterized by XPS, FTIR and SEM analyses before and after soaking in water. The water stability was also investigated by weight loss measurement. A high retention of carboxylic moieties, i.e. functional groups of the monomer has been observed for coatings deposited under mild conditions for the jet (low frequency and high jet speed). These films have been used for cell adhesion using human ovarian carcinoma cells (NIH:OVCAR‐3). Good results have been obtained depending on the plasma parameters, showing that atmospheric pressure plasma jet is a promising technique to grow organic thin films for biomedical applications.magnified image
Analysis of the Pressure Gradients According to Capsule Flow Mechanism
Authors: Ulusarslan Deniz 
Published: July 2012

AbstractThis study investigated the experimental coefficient in the mathematical correlation for the pressure gradient of spherical capsule train flow according to flow regimes. The investigation was carried out in the 1.2 × 104 < Re < 1.5 × 105 range and under transport concentration of 5 – 30 %. Deviation between the pressure drops measured by experiment and the mathematical correlation was calculated based on new experimental coefficients. The total pressure gradient in the two‐phase flow of the mixture was distinguished as pressure gradients caused by homogeneous flow and those caused by pressure drops, depending on the rotational movement of the capsules. The experimental findings indicate that at lower concentrations, the losses caused by the rotational movement are low, but the losses caused by the homogeneous flow are high. Losses caused by the rotational movement increase as the concentration increases.
A 4 year prospective study to determine risk factors for severe community acquired pneumonia in children in southern China
Authors: Zhang Qingli , Guo Zhongqin , Bai Zhenjiang , MacDonald Noni E. 
Published: July 2012

AbstractBackgroundPneumonia is the major cause of death under 5 years. With high CAP numbers in China and growing access to PICUs, factors associated with severe CAP need to be determined to optimize care.ObjectiveTo prospectively determine PICU CAP admission features and outcomes.MethodsA 4 year prospective study of CAP aged 1 month to <14 years admitted to PICU, Children's Hospital Affiliated to Soochow University, China. All were managed in a standard manner. Clinical, laboratory, and imaging findings were collected systematically. All received antibiotics.ResultsEight hundred ten (7%) of 10,836 CAP hospital admissions needed PICU. Seven hundred seven (87%) were enrolled. PICU CAP children were young (76% ≤ 12 months) and 33% had co‐morbid conditions; 21% congenital heart disease.21% required mechanical ventilation. The average length of PICU stay was 5 days (range, 3–27). The case fatality rate was 5.8%. Viruses were detected in 38%, RSV 24%; bacteria in 23%, Streptococcus pneumoniae 7%, Haemophilus influenza b 4%, Mycoplasma 11%. On single factor analysis, PICU admission respiratory rate >70/min, grunting/groaning, head nodding, cyanosis, and anemia were associated with respiratory failure and with fatality. On multivariate analysis only presence of congenital heart disease, Trisomy 21 and immunodeficiency correlated with fatality; not microbe nor PICU findings.ConclusionsYoung age and underlying congenital heart disease were associated factors for PICU support in CAP in China. Early referral if altered sensorium, high respiratory rate, head nodding, grunting and anemia, and universal access to conjugated vaccines may decrease morbidity and mortality. Pediatr Pulmonol. 2013; 48:390–397. © 2012 Wiley Periodicals, Inc.
Systemic effects of thiamethoxam and chlorantraniliprole seed treatments on adult Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in rice
Authors: Lanka Srinivas K , Ottea James A , Davis Jeffrey A , Hernandez Amy B , Stout Michael J 
Published: July 2012

AbstractBACKGROUND: Feeding assays using adult rice water weevils and foliage of plants treated as seeds with chlorantraniliprole and thiamethoxam at different rates were conducted to evaluate the systemic adulticidal and feeding effects. Dose–mortality relationships were determined for thiamethoxam seed treatments by combining leaf area lost due to feeding and insecticide residues analyzed by LC/MS/MS. Changes in adulticidal activity of thiamethoxam were also investigated by contrasting adult mortalities at the 5–6‐leaf and tillering stages of rice.RESULTS: Adult weevil mortalities and leaf consumption rates on foliage were affected in thiamethoxam but not in chlorantraniliprole treatments when rice was at the 6–7‐leaf stage. The LD50 for weevils feeding on thiamethoxam‐treated rice at the 2–3‐leaf stage was 447 pg insecticide weevil−1 (95% CL: 25–830 pg weevil−1) but was lower (142 pg weevil−1; 95% CL: 102–180 pg weevil−1) in experiments with 3–4‐leaf‐stage plants. Mortalities on leaves from 5–6‐leaf‐stage plants were consistently higher than on leaves from tillering plants. Thiamethoxam residues measured by ELISA increased with seed treatment rate and differed between plant stages.CONCLUSION: The LD50 values developed in this study are the first values for leaf‐feeding insects on foliage of plants treated as seeds with thiamethoxam. The attrition of adulticidal activity of thiamethoxam in foliage of older plants may help to explain the reduced effectiveness of seed treatments against rice water larvae that is seen at later stages of rice growth in field studies. The differential activity of these two seed treatments on adults suggests that adult mortality contributes to the field efficacy of thiamethoxam but not to that of chlorantraniliprole. Copyright © 2012 Society of Chemical Industry
High‐level of resistance to spinosad, emamectin benzoate and carbosulfan in populations of Thrips tabaci collected in Israel
Authors: Lebedev Galina , Abo‐Moch Fauzi , Gafni Guy , Ben‐Yakir David , Ghanim Murad 
Published: July 2012

AbstractBACKGROUND: The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips.RESULTS: The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC50 values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested.CONCLUSION: This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry