bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of molecular architectures for polymeric mesophase formation
Authors: Pugh Coleen , Liu Hui , Arehart Stephen V. , Narayanan Ramasubramanian 
Published: March 2011

AbstractBased on the tendency of low molar mass liquid crystals composed of extended mesogens symmetrically disubstituted with long n‐alkoxy substituents to exhibit smectic C mesophases, we have proposed that SCLCPs with laterally attached (vs. terminally attached) mesogens offer an ideal architecture for obtaining sC* mesophases. In particular, mesogens that typically form the desirable sC*‐n phase sequence can be laterally attached to the polymer backbone through a chiral spacer, which should result in high values of spontaneous polarization. Not only are we using mesogens which exhibit sC*‐n phase sequences, we are also attempting to induce smectic layering into systems which typically form nematic mesophases by using immiscible hydrocarbon/fluorocarbon components and electron‐donor‐acceptor interactions. Thus far, the thermotropic behavior of poly{5‐[[[2', 5'‐bis[(3″‐fluoro‐4″‐dimethoxyphenyl)ethynyl]benzyl]oxy]carbonyl[2.2.1]hept‐2‐ene]s and poly(5‐[[[2',5'‐bis[(3″‐fIuoro‐4″‐methoxybenzoyl)oxy]benzyl]oxy]carbonyl]‐bicyclo[2.2.1]hept‐2‐ene)s correspond to that of their low molar mass analogs. Preliminary results demonstrate that smectic layering is successfully induced in 2,5‐bis[(4'‐n‐alkoxybenzoyl)oxy]toluenes and polynorbornenes with laterally attached 2,5‐bis[(4'‐n‐alkoxybenzoyl)oxy]benzyl mesogens by terminating the n‐alkoxy substituents with perfluorinated segments.
Towards helical coordination polymers: Molecular wires in chiral coats
Authors: Constable Edwin C. 
Published: March 2011

AbstractThe use of functionalised 2,2':6',2″‐terpyridines and multi‐domain ligands based upon this metal‐binding motif for the assembly of co‐ordination oligomers is discussed. The extension of the methodology to the preparation of helical polymers is demonstrated.
Supramolecular polymers having chiral interactions
Authors: Ogata Naoya 
Published: March 2011

AbstractPoly(L‐glutamate) having amphiphilic side chains was designed as membrane materials for optical resolution of α‐amino acids. Solvent‐cast films of the poly(glutamate) (PLG) had a self‐ordered structure containing α‐helix of the poly(L‐glutamate). Optical resolutions of various amino acids were carried out through the thin membranes of the amphiphilic poly(L‐glutamate). Racemic mixtures of Tryptophan were completely separated through the membrane. Mechanism of the optical resolutions was investigated in terms of molecular recognitions of racemic Tryptophan by the ordered structure of the membrane. Polymers having pendant PLG and α‐amino acids were synthesized and their permeation behaviors were investigated.
Macromolecules with specific constitution and supramolecular structures
Authors: Eisenbach C. D. , Degelmann W. , Göldel A. , Heinlein J. , Terskan‐Reinold M. , Schubert U. S. 
Published: March 2011

AbstractSegmented triblock and multiblock copolymers consisting of highly flexible polydisperse segments and molecularly uniform segments of well defined architecture capable of either the formation of a mesophase, chainfolded crystallites or double‐helical metal complexes have been synthesized; the bulk superstructure as well as the physical and material properties correlated with the primary structure: block copolymers with liquid crystalline segments formed microphase separated systems, and the phase behaviour depended on the constitutional composition. Multiblock copolymers with symmetrically chain‐folded polyurethane hard segments and associative groups in the chain fold led to specially shaped lamellar superstructures. Block copolymers with bipyridine containing segments gave tetracoordinated and double‐helical copper(I) complexes which segregated resulting in supramolecular polymer systems.
New complex macromolecular architectures based on organosilicon chemistry
Authors: Boileau S. , Khalifa R. Ben , Jallouli A. , Lestel L. , Teyssié D. 
Published: March 2011

AbstractPolycarbosilane networks were prepared from well‐defined α, ω‐difunctional oligomers: X‐[Si(CH3)2‐CH2‐CH2]n‐X with X = H (1) and X = CH=CH2 (2). Crosslinking reactions were performed by hydrosilylation of tetramethyltetravinylcyclotetrasiloxane (V4) or of tetravinylsilane with SiH end groups of 1. Hydrosilylation of Si‐CH=CH2 end groups of 2 with tetramethyltetrahydrocyclotetrasiloxane (D4H) was also successfully tried. Some physicochemical properties of these new networks will be presented.1)Interpenetrating networks based on polysiloxanes and polycarbonates were synthesized by the in situ method: a polysiloxane bearing various proportions of room temperature crosslinkable ‐Si(OEt)3 side groups was mixed with bis(allyl ethylene glycol) biscarbonate and a free‐radical initiator. After the formation of the first network at room temperature, the cross‐linking of the polycarbonate network was performed by raising the temperature up to 80°C. Various chemical modifications of the polysiloxane component in the IPN were performed in order to improve the degree of interpenetration as estimated from turbidity, density, refractive index and DSC measurements.2)
Inorganic‐organic composites, including some examples involving polyamides and polyimides
Authors: Mark J. E. , Wang S. , Ahmad Z. 
Published: March 2011

AbstractInorganic‐organic composites are frequently synthesized using techniques very similar to those used in the new sol‐gel approach to ceramics. Organometallics such as silicates, titanates, and aluminates are hydrolyzed in the presence of polymer chains that typically contain reactive groups for bonding onto the silica, titania, or alumina being formed in the hydrolysis, thus forming inorganic‐organic composites. When the polymer chains are present in excess, they constitute the continuous phase, with the ceramic‐type material appearing as reinforcing particles. When present in smaller amounts, the polymer is dispersed in the continuous ceramic phase, to give a polymer‐modified ceramic. Under some conditions, bicontinuous systems are obtained. The composites thus prepared are characterized by electron microscopy, x‐ray and neutron scattering intensities, density determinations, and stress‐strain and impact‐strength measurements. Some unique challenges, problems, and results involved in the application of these techniques to high‐performance polyamides and polyimides are described.
Recent advances in ferroelectric polymers
Authors: Scheinbeim J. I. , Newman B. A. 
Published: March 2011

AbstractIn the Polymer Electroprocessing Laboratory at Rutgers University, we have discovered that the odd‐numbered nylons constitute the second known class of ferroelectric polymers1–3, and that polarized films exhibit piezoelectric properties similar to poly(vinylidene fluoride) (PVF2) and copolymers of PVF2 and trifluoroethylene (PVF2/PVF3). A study of a series of these polymers including nylon 11, nylon 9, nylon 7 and nylon 5 showed that the remanent polarization produced in quenched, cold‐drawn films was a linear function of polymer dipole density4. The highest remanent polarization produced was that of nylon 5, the value attained (P1=125mC/m2) being approximately 2.5 times that of PVF2. We also discovered that (unlike PVF2 or PVF2/PVF3) the remanent polarization could be stabilized to elevated temperatures (close to the polymer melting point). For nylon 5, the remanent polarization and piezoelectric response was stable to over 250°C5. We showed that the hydrogen‐bonded sheet structure in nylon 11 for quenched cold‐drawn films was parallel to the plane of the film, and that after application of high electric fields the hydrogen‐bonded sheet structure was rotated 90° to an orientation perpendicular to the plane of the film3.A detailed X‐ray diffraction study of the effects of humidity and electroprocessing on the switching behavior of nylon 5, nylon 7 and nylon 11 films was carried out5. The piezoelectric and pyroelectric response6 of these films was also determined. The different switching mechanisms observed and the measured piezoelectric and pyroelectric properties will be presented and discussed.
Moderately concentrated solutions of polystyrene, part 5. Static and dynamic light scattering in bis(2‐ethylhexyl) phthalate
Authors: Yue Shunqiong , Berry Guy C. 
Published: March 2011

AbstractStatic and dynamic light scattering data are reported on dilute and moderately concentrated solutions of a high molecular weight polystyrene (Mw= 3.61 × 106) in bis(2‐ethylhexyl) phthalate under Flory Theta conditions. The data cover a concentration range with 0.03 × [η]c × 3.5, with several concentrations large enough that the product cMwexceeds the value necessary for entanglement behavior. The results show that a certain intermolecular scattering function H(q, c) often approximated by unity should not be neglected in the evaluation of the correlation length in the static scattering from moderately concentrated solutions of flexible chain polymers. An approximate form for H(q, c) for moderately concentrated solutions is consistent with a soft spherically symmetric repulsive potential among the chains. The dynamic scattering show two distinct groups of relaxation rates at all concentrations, but the interpretation of the two modes changes as the concentration increases from low concentrations ([η]c < 1) to higher concentrations. At low concentrations the slower mode corresponds to mutual diffusion, and the faster mode to intramolecular dynamics. For concentrations with [η]c > 2.4 the slow mode is viscoelastic in origin, and the faster mode is diffusive. The behavior is compared with theoretical predictions in both regimes.
Biochemie 2010
Authors: Jäschke Andres , Micura Ronald , Grünweller Arnold , Hartmann Roland , Helm Mark , Liebl Wolfgang , Merkel Lars , Budisa Nediljko , Sundermann Uschi , Kushnir Susanna , Schulz Frank 
Published: March 2011

AbstractNukleotidmodifikationen: Wertvoll für Grundlagenforschung und therapeutische Anwendung. Synthetische Biologie: Was ist sie, welche Perspektiven hat sie und welche Techniken setzt sie ein?Kombinatorische Biosynthese: Jenseits der Polyketide.
Concurrent motion planning and reaction load distribution for redundant dynamic systems under external holonomic constraints
Authors: Kim Joo H. , Abdel‐Malek Karim , Xiang Yujiang , Yang Jingzhou (James) , Arora Jasbir S. 
Published: March 2011

AbstractDynamics of mechanical systems during motion usually involves reaction forces and moments due to the interaction with external objects or constraints from the environment. The problems of determining the external reaction loads have often been addressed in the literature in terms of forward dynamics solution methods for non‐redundant systems. In this article, we propose a numerical formulation of distributing the external reaction loads of redundant systems concurrently with optimal motion planning and simulation. For dynamic equilibrium, the resultant reaction loads that include the effects of inertia, gravity, and general applied loads are distributed to each contact point. Unknown reactions are determined along with the system configuration at each time step using iterative non‐linear optimization algorithm. The required actuator torques as well as the motion trajectories are obtained while satisfying the given holonomic constraints. The formulation is applied with two types of discretization methods for the reactions, and several example motions of multi‐rigid‐body systems, such as a simple 3‐degree‐of‐freedom mechanical manipulator and a highly articulated whole‐body human mechanism, are demonstrated. The example results are compared with the cases where the reactions are pre‐assigned. The proposed numerical formulation demonstrates the realistic distribution of external reaction loads and the associated goal‐oriented motions that are dynamically consistent, and provides alternate schemes for hybrid motion/force control of redundant robots. Copyright © 2011 John Wiley & Sons, Ltd.
Isogeometric finite element data structures based on Bézier extraction of T‐splines
Authors: Scott Michael A. , Borden Michael J. , Verhoosel Clemens V. , Sederberg Thomas W. , Hughes Thomas J. R. 
Published: March 2011

AbstractWe develop finite element data structures for T‐splines based on Bézier extraction generalizing our previous work for NURBS. As in traditional finite element analysis, the extracted Bézier elements are defined in terms of a fixed set of polynomial basis functions, the so‐called Bernstein basis. The Bézier elements may be processed in the same way as in a standard finite element computer program, utilizing exactly the same data processing arrays. In fact, only the shape function subroutine needs to be modified while all other aspects of a finite element program remain the same. A byproduct of the extraction process is the element extraction operator. This operator localizes the topological and global smoothness information to the element level, and represents a canonical treatment of T‐junctions, referred to as ‘hanging nodes’ in finite element analysis and a fundamental feature of T‐splines. A detailed example is presented to illustrate the ideas. Copyright © 2011 John Wiley & Sons, Ltd.
Polymorphisms of the SLCO1B1 gene predict methotrexate‐related toxicity in childhood acute lymphoblastic leukemia
Authors: Lopez‐Lopez Elixabet , Martin‐Guerrero Idoia , Ballesteros Javier , Piñan M. Angeles , Garcia‐Miguel Purificacion , Navajas Aurora , Garcia‐Orad Africa 
Published: March 2011

AbstractBackgroundMethotrexate (MTX) is an important component of the therapy for childhood acute lymphoblastic leukemia. Treatment with high‐dose MTX often causes toxicity, recommending a dose reduction and/or cessation of treatment. Polymorphisms in genes involved in the MTX metabolism have been associated with toxicity with controversial results. The discrepancies could be due to differences in treatment protocols among studies, small, or non‐homogeneous populations or the use of different toxicity criteria. The aim of the present study was to analyze the possible correlation of polymorphisms of genes involved in the MTX metabolism with the toxicity during therapy with the well‐established LAL/SHOP protocol.ProcedureWe analyzed 10 polymorphisms in seven genes (MTHFR, TS, SHMT1, RFC1, ABCB1, ABCG2, and SLCO1B1) from the MTX metabolism in 115 Spanish pediatric B‐ALL patients, using MTX plasma concentration as an objective and quantifiable marker of toxicity.ResultsWe confirmed the suitability of MTX plasma levels as a toxicity marker. We found a statistically significant association between MTX plasma concentration and the SLCO1B1 rs11045879 CC genotype (P = 0.030). The rs4149081 AA genotype, in the same gene, could also be an indicator for high‐MTX plasma concentrations. We did not find any significant association in the other genetic polymorphisms analyzed.ConclusionsIdentification of the rs4149081 and rs11045879 SLCO1B1 polymorphisms in children with ALL could be a useful tool for monitoring patients at risk of low‐MTX clearance in order to avoid MTX‐related toxicity. Pediatr Blood Cancer 2011; 57: 612–619. © 2011 Wiley‐Liss, Inc.
Application of 2‐D DIGE to survey the quality of biological medicines
Authors: Miller Ingrid , Gemeiner Manfred , Göstl Georg , Weber Alfred , Unkelbach Uwe , Beck Gerhard , Lackner Friedrich 
Published: March 2011

Abstract2‐D DIGE was used to investigate ‘fingerprint proteins’ in biological medicines. A presumably non‐originator human albumin was analysed, and the 2‐D DIGE patterns of the non‐genuine and the authentic product were compared. The products could be clearly distinguished based on the pattern of minor components, which represent plasma proteins and degradation products remaining in the final products after fractionation and purification. The approach demonstrated that 2‐D DIGE is an excellent tool for the analysis of biologicals of different sources and for ensuring the identity and quality of blood products.
Toward a definition of the complete proteome of plant peroxisomes: Where experimental proteomics must be complemented by bioinformatics
Authors: Reumann Sigrun 
Published: March 2011

AbstractIn the past few years, proteome analysis of Arabidopsis peroxisomes has been established by the complementary efforts of four research groups and has emerged as the major unbiased approach to identify new peroxisomal proteins on a large scale. Collectively, more than 100 new candidate proteins from plant peroxisomes have been identified, including long‐awaited low‐abundance proteins. More than 50 proteins have been validated as peroxisome targeted, nearly doubling the number of established plant peroxisomal proteins. Sequence homologies of the new proteins predict unexpected enzyme activities, novel metabolic pathways and unknown non‐metabolic peroxisome functions. Despite this remarkable success, proteome analyses of plant peroxisomes remain highly material intensive and require major preparative efforts. Characterization of the membrane proteome or post‐translational protein modifications poses major technical challenges. New strategies, including quantitative mass spectrometry methods, need to be applied to allow further identifications of plant peroxisomal proteins, such as of stress‐inducible proteins. In the long process of defining the complete proteome of plant peroxisomes, the prediction of peroxisome‐targeted proteins from plant genome sequences emerges as an essential complementary approach to identify additional peroxisomal proteins that are, for instance, specific to peroxisome variants from minor tissues and organs or to abiotically stressed model and crop plants.
Crystal structures of 3‐methyl‐2(1H)‐quinoxalinone and three substituted derivatives
Authors: Mondieig Denise , Negrier Philippe , Massip Stéphane , Leger Jean Michel , Jarmoumi Chakir , Lakhrissi Brahim 
Published: March 2011

Abstract3‐Methyl‐2(1H)‐quinoxalinone and three derivatives (3,7‐dimethyl‐2(1H)‐quinoxalinone, 3‐methyl‐6,7‐dichloro‐2(1H)‐quinoxalinone and 3‐methyl‐7‐nitro‐2(1H)‐quinoxalinone) have been synthesised and analysed by 1H NMR and IR spectral spectroscopies. The crystal structures have been determined at room temperature from X‐ray single crystal diffraction data for three of them and from powder diffraction data for the nitro derivative. 3‐Methyl‐2(1H)‐quinoxalinone crystallises in the P21/c monoclinic system, 3,7‐dimethyl‐2(1H)‐quinoxalinone in the Pbca orthorhombic system and the two others compounds in the P$\overline {1} $ triclinic system. For the nitro derivative, CH$\cdots $N short contacts are established between the carbon of the methyl and the double bounded nitrogen of the ring. For the three other compounds NH$\cdots $O hydrogen bonds involve the atoms of the heterocyclic ring. Copyright © 2011 John Wiley & Sons, Ltd.
Knowledge, attitude and perceptions of breast cancer screening among native and immigrant women in Barcelona, Spain
Authors: Pons‐Vigués Mariona , Puigpinós‐Riera Rosa , Serral Gemma , Pasarín M. Isabel , Rodríguez Dolors , Pérez Glòria , Benet Josep , Casamitjana Montserrat , Borrell Carme 
Published: March 2011

AbstractObjectiveInequalities between immigrant and native populations in terms of access and use of health services have been described. The objective is to compare knowledge, attitudes, vulnerabilities, benefits and barriers related to breast cancer (BC) and screening mammography among women from different countries resident in Barcelona.MethodsA cross‐sectional survey carried out in Barcelona in 2009. The study population consisted of female residents in Barcelona between 45 and 69 years of age; participants were Spanish nationals or immigrants from low‐income countries. 960 participants were asked 72 questions, mainly with Likert responses. The dependent variables were five quantitative scales: (1) knowledge of BC and early detection, (2) attitude towards health and BC, (3) vulnerability to BC, (4) barriers to mammography, (5) benefits of mammography. The independent variables were country of origin, social class, setting, cohabitation, age, mammography use, length of residence and fluency of the language. Analyses compared scale scores stratified by the independent variables. Multivariable linear regression models were fitted to determine the relationship between the scales and the independent variables.ResultsWe observed inequalities according to country of origin on all scales after adjustment for independent variables. Chinese women presented the greatest differences with respect to native women, followed by Maghrebi and Filipino women. Inequalities exist on the vulnerability and barriers scales according to social class and urban/rural setting, and on the attitude scale according to social class.ConclusionsCountry of origin, social class and urban/rural setting are key contributors to inequality in these scales.Copyright © 2011 John Wiley & Sons, Ltd.
Characterization of Ag/TlInSe2/Ag structure
Authors: Qasrawi A. F. , Gasanly N. M. 
Published: March 2011

AbstractIn this work, the current–voltage characteristics of Ag/TlInSe2/Ag and In/TlInSe2/In structures, the incident light intensity and time dependencies of photocurrent as well as the response time–illumination intensity dependence of Ag/TlInSe2/Ag structures have been studied. For bias voltages larger than 120.0 and 4.0 V, the current injection was found to be space‐charge limited and was assigned to the existing of deep and shallow hole traps being located at 210 and 16 meV for Ag and In‐contacted samples, respectively. While indium‐contacted samples show S‐shaped I–V dependence above bias voltage of 10.0 V, silver contacted samples does not show this behavior even at 200.0 V. For the Ag/TlInSe2/Ag structure, photocurrent was observed to exhibit stable values in a very short period of time. The device response time decreases with increasing illumination intensity, it exhibits a value of 0.13 s at incident light intensity of 53.6 mW cm−2. The decrement in response time with increasing illumination intensity is associated with an increment in photocurrent at the same ratio. The ohmic behavior up to high voltages (120 V), the fast response time and the large spatial photocurrent make the Ag/TlInSe2/Ag structure promising IR detectors.
Impurity strength and impurity domain modulated frequency‐dependent linear and second non‐linear response properties of doped quantum dots
Authors: Datta Nirmal Kumar , Ghosh Manas 
Published: March 2011

AbstractWe explore the pattern of frequency‐dependent linear and second non‐linear optical responses of repulsive impurity doped quantum dots harmonically confined in two dimensions. The dopant impurity potential chosen assumes a Gaussian form and it is doped into an on‐center location. The quantum dot is subject to a periodically oscillating external electric field. For some fixed values of transverse magnetic field strength (ωc) and harmonic confinement potential (ω0), the influence of impurity strength (V0) and impurity domain (ξ) on the diagonal components of the frequency‐dependent linear (αxx and αyy) and second non‐linear (γxxxx and γyyyy) responses of the dot are computed through a linear variational route. The investigations reveal that the optical responses undergo enhancement with increase in both V0 and ξ values. However, in the limitingly small dopant strength regime one observes a drop in the optical responses with increase in V0. A time‐average rate of energy transfer to the system is often invoked to support the findings.