bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature Dependence of the Back‐Stress in Shear for Glassy Polycarbonate
Authors: Negahban Mehrdad , Strabala Kyle , Delabarre Pierre , Goel Ashwani , Feng Ruqiang , Grene Jean 
Published: November 2007

AbstractSummary: Back‐stress is the equilibrium stress and represents conditions under which relaxation events in the material stop and the material can carry an applied load indefinitely without a change in strain. In most models for glassy polymers, back‐stress plays a central role since relaxation in materials is closely related to the distance of the current conditions from equilibrium. A number of these models that are commonly used for modeling glassy polymers use a modeling structure similar to large deformation plasticity. The flow rule for the plastic strain in these models are directly connected to the “over‐stress,” a properly invariant difference between the stress and the back‐stress. The importance of correctly evaluating the back‐stress to use in these models is clear. For this class of models, the authors have recently developed a method for directly calculating the back‐stress under shear deformations. This method is based on evaluating the slope of the stress‐strain response under conditions of similar elastic and plastic strain, but different strain rates. Since plastic flow goes to zero at equilibrium, the back‐stress can be found by locating points of zero plastic strain rate. Using the proposed method, the back‐stress in glassy polycarbonate has been evaluated under shear in isothermal tests going from room temperature to 120 °C, just below the glass transition temperature for polycarbonate. The proposed method provided a full map of the back‐stress for polycarbonate over a large range of shear strain and temperature.
Liquid Chromatography of Synthetic Polymers under Limiting Conditions of Insolubility III
Authors: Berek Dušan 
Published: November 2007

AbstractSummary Performance was evaluated of silica based commercial monolithic rod‐like columns in liquid chromatography of synthetic polymers under limiting conditions of enthalpic interactions (LC LC). LC LC employs the barrier effect of the pore permeating and therefore slowly eluting small molecules toward the pore excluded, fast eluting macromolecules. Phase separation (precipitation) barrier action was applied in present study. The barrier was created either by the narrow pulse of an appropriate nonsolvent injected into the column just before the sample solution (LC LC of insolubility – LC LCI) or by the eluent itself. In the latter case, the polymer sample was dissolved and injected in a good solvent (LC LC of solubility – LC LCS). In LC LCI, polymer species cannot break thru the nonsolvent zone while in LC LCS they cannot enter eluent, which is their precipitant. Therefore, polymer species keep moving in the zone of their original solvent. Macromolecules eluting under the LC LC mechanism leave the column in the retention volume (VR) roughly corresponding to VR of the low molar mass substances and can be efficiently separated from the polymer species non‐hindered by the barrier action. The known advantages of monoliths were confirmed. From the point of view of LC LCI and LC LCS the most important quality of monolithic columns represents their excellent permeability, which allows both working at high flow rates and injecting very high (in the range of 5%) sample concentrations. Monolithic column tolerate also extremely high molar mass samples (M>10,000 kg · mol−1). On the other hand, the mesopores (separation pores) of the tested monoliths exhibited rather small volume and wide size distribution. These shortcomings partially impair the permeability advantage of monoliths because in order to obtain high LC LC separation selectivity a tandem of several monolithic columns must be applied. Presence of large mesopores also reduces applicability of monolithic columns for molar masses below about 50 kg · mol−1 because VRs of polymers eluted behind the barrier are similar to that of freely eluting species. The non‐ negligible break‐thru phenomenon was observed for the very high polymer molar masses largely eluting behind the barrier. It is assumed that the fraction of very large mesopores present in the monoliths or association/microphase separation of macromolecules may be responsible for this phenomenon. This is why the presently marketed SiO2 monolithic columns are mainly suitable for the fast purification of the LC LC eluting macromolecules from the polymeric admixtures non‐hindered by the barrier‐forming liquid. Still, monolithic columns have large potential in the LC LCI and LC LCS procedures provided size (effective diameter) of the mesopores can be reduced and their volume increased.
Kinetics of Stable Free Radical Mediated Polymerization inside Submicron Particles
Authors: Tobita Hidetaka 
Published: November 2007

AbstractControlled/living radical polymerization systems in which the active period is extremely small, ϕA ≪ 1, such as the cases of stable free radical mediated polymerization (or nitroxide mediated polymerization) and atom transfer radical polymerization, are considered theoretically. The polymerization rate, Rp, for such systems increases by lowering the trapping agent concentration [X]. When the polymerization is conducted inside small particles, Rp decreases with D below the diameter Dp,SMC at which a single molecule concentration (SMC) is equal to [X]bulk. On the other hand, when the average number of trapping agents in a particle $\bar n_X$ is smaller than about 10, the fluctuation of nX among particles is significant, which leads to a larger Rp than in the cases where all particles contain the same nX. Because of the effects of SMC and fluctuation, Rp may show an acceleration window, Dp,SMC < Dp < Dp,Fluct where Rp is slightly larger than that in bulk.magnified image
Identification of desulphoglucosinolates in Brassicaceae by LC/MS/MS: Comparison of ESI and atmospheric pressure chemical ionisation‐MS
Authors: Zimmermann Nadine S. , Gerendás Jóska , Krumbein Angelika 
Published: November 2007

AbstractIn order to develop a sensitive method for the detection of desulphoglucosinolates by HPLC‐MS, the two most common interfaces for HPLC‐MS, atmospheric pressure chemical ionisation (APCI) and ESI, were compared. While working with the APCI‐interface the evaporation temperature and corona amperage were optimised. In doing so 300°C and 6 μA proved to be most suitable for aliphatic and indole desulphoglucosinolates. The use of formic acid instead of water in the eluent in HPLC‐ESI‐MS measurements increased the sensitivity for the indole desulphoglucosinolates in the presence of 1 mM formic acid, while the sensitivity for the aliphatic desulphoglucosinolate desulphoglucoraphanin was substantially increased by the presence of 5 mM formic acid. Using an Agilent ion trap, two optimisation procedures for the MS parameters, smart and expert mode, were available. In smart mode the software optimises several parameters automatically, which is much more time efficient than expert mode, in which the optimisation is done manually. It turned out that ESI‐MS is most sensitive in smart mode, while for APCI‐MS a higher sensitivity could be gained using the expert mode. Comparing both interfaces, APCI‐MS was more sensitive than ESI‐MS. However, no additional information, in terms of structure determination, was obtained by APCI‐MS.
Apolipoprotein E genotype and alpha‐tocopherol modulate amyloid precursor protein metabolism and cell cycle regulation
Authors: Huebbe Patricia , Schaffer Sebastian , Jofre‐Monseny Laia , Boesch‐Saadatmandi Christine , Minihane Anne‐Marie , Müller Walter E. , Eckert Gunter P. , Rimbach Gerald 
Published: November 2007

AbstractApolipoprotein E4 (apoE4) genotype is associated with an increased risk for Alzheimer's disease (AD). This is thought to be in part attributable to an impact of apoE genotype on the processing of the transmembrane amyloid precursor protein (APP) thereby contributing to amyloid beta peptide formation in apoE4 carriers, which is a primary patho‐physiological feature of AD. As apoE and alpha‐tocopherol (α‐toc) have been shown to modulate membrane bilayer properties and hippocampal gene expression, we studied the effect of apoE genotype on APP metabolism and cell cycle regulation in response to dietary α‐toc. ApoE3 and apoE4 transgenic mice were fed a diet low (VE) or high (+VE) in vitamin E (3 and 235 mg α‐toc/kg diet, respectively) for 12 weeks. Cholesterol levels and membrane fluidity were not different in synaptosomal plasma membranes isolated from brains of apoE3 and apoE4 mice (–VE and +VE). Non‐amyloidogenic alpha‐secretase mRNA concentration and activity were significantly higher in brains of apoE3 relative to apoE4 mice irrespective of the dietary α‐toc supply, while amyloidogenic beta‐secretase and gamma‐secretase remained unchanged. Relative mRNA concentration of cell cycle related proteins were modulated differentially by dietary α‐toc supplementation in apoE3 and apoE4 mice, suggesting genotype‐dependent signalling effects on cell cycle regulation.
Shape reconstruction for the time‐dependent Navier‐Stokes flow
Authors: Yan Wen‐Jing , Ma Yi‐Chen 
Published: November 2007

AbstractThis article deals with the shape reconstruction of a bounded domain with a viscous incompressible fluid driven by the time‐dependent Navier‐Stokes equations. For the approximate solution of the ill‐posed and nonlinear problem we propose a regularized Newton method. A theoretical foundation for the Newton method is given by establishing the differentiability of the initial boundary value problem with respect to the interior boundary curve in the sense of the domain derivative. Numerical examples indicate the feasibility of our method. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2008
Production of superhydrophobic polymer fibers with embedded particles using the electrospinning technique
Authors: Menini Richard , Farzaneh Masoud 
Published: November 2007

AbstractSuperhydrophobic materials are currently used for their water‐repelling, self‐cleaning and anti‐fouling properties but are also potentially attractive to prevent snow or ice accumulation on exposed structures. Using the electrospinning technique, polymer mats made of polystyrene and poly[tetrafluoroethylene‐co‐(vinylidene fluoride)‐co‐propylene] (PTVFP) were prepared. They were found to show highly hydrophobic properties, water contact angle (CA) between 130 and 150°, when a dual fiber–bead microstructure was observed. Superhydrophobicity, CA > 150°, was reached when PTVFP mats were electrospun from a polymer solution containing dispersed polytetrafluoroethylene (PTFE) nanoparticles. Using atomic force microscopy imaging, protruding nanosized asperities on fiber and bead surfaces were observed and this structure led to superhydrophobic properties. Materials prepared from a high‐viscosity PTVFP/ethyl acetate solution with PTFE particles, 200 nm diameter and 8% (w/w), showed an 11.2% improvement in hydrophobicity, CA = 161°, compared to the materials obtained from a particle‐free polymer solution (CA = 143°). Copyright © 2007 Society of Chemical Industry
On the detection of shunts in silicon solar cells by photo‐ and electroluminescence imaging
Authors: Breitenstein Otwin , Bauer Jan , Trupke Thorsten , Bardos Robert A. 
Published: November 2007

AbstractRecently electroluminescence (EL) and photoluminescence (PL) imaging were reported to allow detection of strong ohmic shunts in silicon solar cells. Comparing lock‐in thermography (LIT) images with luminescence images of various shunted cells, measured under different conditions, the ability of luminescence techniques for shunt detection is investigated. Luminescence imaging allows identifying ohmic shunts only if they reach a certain strength. The detection limit for PL measurements of linear shunts was estimated to be in the order of 15 mA at 0·5 V bias for a point‐like shunt in multicrystalline (mc) cells. Pre‐breakdown sites can also be detected by electroluminescence under reverse bias. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and characterization of monodisperse superparamagnetic poly(vinyl alcohol) beads by reverse spray suspension crosslinking
Authors: Yang Chengli , Guan Yueping , Xing Jianmin , Shan Guobin , Liu Huizhou 
Published: November 2007

AbstractA novel protocol for preparing magnetic poly(vinyl alcohol) (PVA) beads by reverse spray suspension crosslinking was reported. The hydrophilic Fe3O4 nanoparticles were mixed with PVA, glutaraldehyde, and water to form aqueous phase. Then the aqueous phase was sprayed into vegetable oil by a pressure of nitrogen gas to form water in oil (W/O) suspension. The magnetic PVA beads were obtained in the presence of hydrochloric acid catalyst. It was found that the magnetic PVA beads obtained good properties when the PVA concentration was 10%, and the oil phase temperature was controlled at 40 °C. The mechanical stirring has little impact on the size of magnetic PVA beads in the process of reverse spray suspension crosslinking. The Cibacron Blue (CB) was coupled on the surface of magnetic PVA beads by surface chemical reaction. The morphology, size, and magnetic properties of the magnetic PVA beads were examined by scanning electron microscopy, laser diffraction, and vibrating sample magnetometer, respectively. Compared with the stirring method, it was found that the size of magnetic PVA beads was monodisperse and their saturation magnetization was much higher. Fourier transform infrared and X‐ray photoelectron spectroscopy experimental results proved that CB molecules were covalently immobilized onto the surface of the magnetic PVA beads. Meanwhile, the protein affinity separation experiments demonstrated that the magnetic PVA beads can potentially be used as a carrier for large‐scale protein separation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 203–210, 2008
Design of Self Compensating Soft Loading Hood
Authors: McBride William , Ilic Dusan 
Published: November 2007

AbstractThis paper presents a design, and a design method, sufficient to engineer a passive solution to the problem of discharge bias resulting from tonnage fluctuation with soft loading transfer chutes. This is achieved by considering the momentum change inherent in the bulk material stream through the hood section of a soft loading transfer point. This momentum change is utilised to move the hood in a predefined path to ensure the discharge centroid remains consistent.The majority of soft loading transfer points are between conveyor belts that include a plan view change in the material direction which immediately impacts on the design of the transfer point. This impact is, the designer must optimise the transfer for a narrow bandwidth of throughput to achieve optimal outcomes or else accept the potential for mis tracking on the receiving belt. This is due to variations in throughput tonnage altering the location of the discharged materials centroid from a fixed hood section, resulting in a tendency for the receiving belt to mistrack due to biased loading.
RAFT Nano‐constructs: surfing to biological applications
Authors: Boturyn Didier , Defrancq Eric , Dolphin Gunnar T. , Garcia Julian , Labbe Pierre , Renaudet Olivier , Dumy Pascal 
Published: November 2007

AbstractBiologically programmed molecular recognition provides the basis of all natural systems and supplies evolution‐optimized functional materials from self‐assembly of a limited number of molecular building blocks. Biomolecules such as peptides, nucleic acids and carbohydrates represent a diverse supply of structural building blocks for the chemist to design and fabricate new functional nanostructured architectures. In this context, we review here the chemistry we have developed to conjugate peptides with nucleic acids, carbohydrates, and organic molecules, as well as combinations thereof using a template‐assembled approach. With this methodology, we have prepared new integrated functional systems exhibiting designed properties in the field of nanovectors, biosensors as well as controlled peptide self‐assembly. Thus this molecular engineering approach allows for the rational design of systems with integrated tailor‐made properties and paves the way to more elaborate applications by bottom‐up design in the domain of nanobiosciences. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Mutations in deoxyribonucleotide biosynthesis pathway cause spreading of silencing across heterochromatic barriers at the mating‐type region of the fission yeast
Authors: Singh Gurjeet , Klar Amar J. S. 
Published: November 2007

AbstractThe mat2,3‐region of Schizosaccharomyces pombe is flanked by two inverted repeat elements, IRL and IRR, which define the boundaries of the silent domain resulting from heterochromatin assembly in the region. We employed a genetic screen to isolate factors whose mutations allowed spreading of heterochromatin across boundary elements. Surprisingly, this screen revealed that mutations in the genes required for deoxyribonucleotide biosynthesis, cdc22 (encoding the large subunit of ribonucleotide reductase) and tds1 (putative thymidylate synthase), cause silencing of marker genes inserted outside of the silent domain. Chromatin‐immunoprecipitation analysis showed that histone H3 lysine 9 methylation modification, an epigenetic mark associated with gene silencing, is enriched by two‐ to three‐fold in the cdc22 mutant as compared to the level found in the wild‐type strain in regions outside the silent domain. The spreading of heterochromatin across barriers required functional Atf1/Pcr1, ATF‐CREB family proteins, but not the RNA‐interference Dcr1, Ago1, or Rdp1 factors, previously implicated in silencing. These results implicate the deoxyribonucleotide biosynthesis pathway in limiting epigenetic controls at barrier elements at the mating‐type region, but the mechanism remains unknown. Published in 2007 by John Wiley & Sons, Ltd.
Problem of crack perturbation based on level sets and velocities
Authors: Kovtunenko V.A. , Kunisch K. 
Published: November 2007

AbstractWe describe cracks with the help of a given velocity as zero‐level sets of a non‐negative function satisfying a transport equation. For smooth velocities this description is equivalent to the coordinate transformation of a domain containing the crack inside. Analytical examples of cracks described by smooth as well as discontinuous velocities are presented in 2D and 3D domains. Based on a level‐set formulation we consider the crack perturbation problem subject to a non‐penetration condition and derive the formula for the shape derivative.
Exhaust explained
Authors: Förster K. 
Published: November 2007

AbstractThe gasdynamic state of a plug of gas which was exhausted through a valve opened for a short time interval is quite inhomogeneous. In this paper a computational method based upon a onedimensional model is revived, and the complicated structure of the plug demonstrated in a realistic example.Der gasdynamische Zustand eines durch ein kurzzeitig geöffnetes Ventil entwichenen Gaspfropfens ist ganz uneinheitlich. Die vorgelegte Arbeit berechnet diesen Zustand auf der Basis des bekannten eindimensionalen Modells und zeigt ein realistisches Beispiel.
A functional type a posteriori error analysis for the Ramberg‐Osgood model
Authors: Bildhauer M. , Fuchs M. , Repin S. 
Published: November 2007

AbstractWe discuss the weak form of the Ramberg‐Osgood equations (also known as the Norton‐Hoff model) for nonlinear elastic materials and prove functional type a posteriori error estimates for the difference of the exact stress tensor and any tensor from the admissible function space. These equations are of great importance since they can be used as an approximation for elastic‐perfectly plastic Hencky materials.
Physical Properties of Two Isomers of Conjugated Linoleic Acid
Authors: Uehara Hidetaka , Suganuma Tomomi , Negishi Satoshi , Uda Yukihiro , Furukawa Yoshinori , Ueno Satoru , Sato Kiyotaka 
Published: November 2007

AbstractThermal properties, powder X‐ray diffraction patterns and FT‐IR absorption spectra of crystals of two isomers of conjugated linoleic acid (CLA), 9‐cis, 11‐trans‐CLA (c9t11), 10‐trans, 12‐cis‐CLA (t10c12) were examined. To search for polymorphic modifications, we carefully performed crystallization from melt and solution phases, and isolated one type of crystalline form in c9t11 and t10c12. The melting temperature (Tm) was 14.9 °C, enthalpy of fusion (ΔH) was 38.7 kJ/mol, and entropy of fusion (ΔS) was 134 J/mol K for c9t11, and Tm = 19.8 °C, ΔH = 35.6 kJ/mol and ΔS = 122 J/mol K for t10c12. The X‐ray diffraction and FT‐IR measurements indicated O⊥ subcell packing in the crystals of c9t11 and t10c12, and long spacing values of 4.22 nm for c9t11 and 3.88 nm for t10c12. The unique molecular structures of the two isomers of CLA are discussed in comparison to the polymorphism of oleic acid, petroselinic acid, elaidic acid and linoleic acid, all of which are unsaturated fatty acids having the same carbon number of 18 as that of the two CLA isomers.
Chronic widespread musculoskeletal pain – A comparison of those who meet criteria for fibromyalgia and those who do not
Authors: Cöster Lars , Kendall Sally , Gerdle Björn , Henriksson Chris , Henriksson Karl G. , Bengtsson Ann 
Published: November 2007

AbstractFibromyalgia is currently classified as chronic widespread pain with widespread allodynia to pressure pain. There are few data describing pain characteristics, quality of life, consequences for daily living, and psychosocial status in patients who meet the classification criteria for fibromyalgia proposed by the American College of Rheumatology compared with patients with chronic widespread pain but not widespread allodynia.This study used a randomly selected sample from the general population. A postal questionnaire and a pain mannequin were sent to 9952 people. The response rate was 76.7%. The pain drawings showed that 345 people had widespread pain; that is, they noted pain in all four extremities and axially. Clinical examination, which included a manual tender point examination, was performed in 125 subjects. These people answered commonly used questionnaires on pain, quality of life, coping strategies, depression, and anxiety.Compared with chronic widespread pain without widespread allodynia, fibromyalgia was associated with more severe symptoms/consequences for daily life and higher pain severity. Similar coping strategies were found. Chronic widespread pain without widespread allodynia to pressure pain was found in 4.5% in the population and fibromyalgia in 2.5%.