bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoreactor‐Assisted Polymerization Toward Stable Dispersions of Conductive Composite Particles
Authors: Korovin Alexey N. , Sergeyev Vladimir G. , Pyshkina Olga A. , Hanske Christoph , Fery Andreas , Wittemann Alexander , Tsarkova Larisa
Published: January 2011

We demonstrate the functioning of a macromolecular nanoreactor which guides a reaction in a confined volume and leads toward improved functional properties of a product material. In our approach, the polymerization of aniline (ANi) is conducted within the interfacial volume of spherical polyelectrolyte brushes (SPB) which are densely affixed to colloidal particles. The SPB provide optimal conditions for matrix polymerization by the efficient confinement of ANi monomers within the finite volume of polyelectrolyte brushes and controlled delivery of the oxidizing reagent to the reaction volume. The excellent kinetic stability of the resulting core–shell particles together with the high macroscopic conductivity of the respective composite open up perspectives for novel materials (a conductive ink).

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Highly Efficient Synthesis of Low Polydispersity Core Cross‐Linked Star Polymers by Ru‐Catalyzed Living Radical Polymerization
Authors: Goh Tor Kit , Yamashita Satoshi , Satoh Kotaro , Blencowe Anton , Kamigaito Masami , Qiao Greg G.
Published: January 2011

The efficient formation of low polydispersity core cross‐linked star (CCS) polymers via controlled/living radical polymerization (LRP) and the arm‐first approach was found to be dependant on the mediating catalyst system. The Ru catalyst, Ru(Ind)Cl(PPh3)2 Cat. 1, and tertiary amine co‐catalyst were used to synthesize highly living poly(methyl methacrylate) (PMMA) macroinitiators, which were then linked together with ethylene glycol dimethacrylate (EGDMA) to form PMMAarmPEGDMAcore CCS polymers. The quantitative and near‐quantitative synthesis of CCS polymers were observed for low to moderate molecular weight macroinitiators ($\overline {M} _{{\rm n}} $ = 8 and 20 kDa), respectively. Lower conversions were observed for high‐molecular weight macroinitiators ($\overline {M} _{{\rm n}} $ ≥ 60 kDa). Overall, an improvement of between 10 and 20% was observed when comparing the Cat. 1 system to a conventional Cu‐catalyzed system. This significant improvement in macroinitiator‐to‐star conversion is explained in the context of catalyst system selection and CCS polymer formation.

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Studies on Morphology and Conductivity of Poly (N‐methyl aniline) Nanoparticles Prepared in Nonstirred Reaction Medium
Authors: Chabukswar Vasant , Dhomase Navnath , Bhavsar Sanjay , Horne Amit , Mohite Kakasaheb , Gaikwad Vishwas
Published: January 2011

Summary: Polyaniline has elicited the most interest due to its wide range of applications in many fields. However insolubility and infusibility are the main factors that affect the application of polyaniline. We have studied and worked on the synthesis of dispersible polyaniline and the results are described here. Poly (N‐methyl aniline) PNMANI nanoparticles with controllable morphology and sizes were prepared by removing a routine operation stirring from the conventional method of synthesis and using acrylic acid as a soft template. It is found that polymer formed in the non‐stirring experiment predominantly produces highly dispersible, smooth nanoparticles with controllable morphology and sizes. These nanoparticles have large surface area and thereby high conductivity. Mechanism for generation of well dispersed and smooth nanoparticles is supported by homogeneous nucleation of polymer nanoparticles in non stirred experiments and the use of acrylic acid as a soft template. In the case of the experiment where the reaction mixture was stirred at 1000 RPM comparatively coral‐like, granular and uncontrolled polymer particles were formed. These coral like granular particles were having comparatively small surface area and less conductivity. Conductivity measurements, UV‐ visible, XRD, FTIR spectroscopy and SEM were performed to characterize the product. This method can be used to synthesize highly conductive polymers in minimum time and bulk quantity.
Physicochemical Characterization of Two Polysulfon‐Amides in Dilute Solution
Authors: Chen Ye , Wu Di , Li Jun , Chen Shenghui , Wang Xiaofeng , Zhang Yumei , Wang Huaping
Published: January 2011

Summary: As one class of high temperature resistant aromatic polymers, polysulfonamides (PSA) are widely used in industry, physicochemical properties and conformation in solution have not been disclosed yet. In this work, the dilute solution behaviour of poly(m‐diphenylsulphone terephthal amide) (m‐PSA) was investigated by laser light scattering (LLS) and viscometry. The results showed that the m‐PSA exists as single chains both in dimethylsulfoxide (DMSO) and dimethylformamide (DMF). The value of radius of gyration to hydrodynamic radius (s/Rh) indicats that the m‐PSA has a random coil conformation in solution. Both the persistence length a and the characteristic ratio C∞ indicate that the m‐PSA chain is flexible in solution. The Mark‐Houwink equation of m‐PSA in DMSO was determined as [η] = 1.62 × 10−5M, and the exponent of 0.87 supports the assumption that m‐PSA forms random coils in DMSO‐solution at 25 °C. It was found that the flexibility of the PSA was affected when 4,4'‐diphenylsulphone terephthalamide monomer was incorporated in backbone. The PSA random copolymer (r‐PSA) with a comonomer ratio of 3:1 (4,4′‐diaminodiphenyl‐ sulfone to 3,3′‐diaminodiphenylsulfone) also had a random coil conformation in DMF; the rigidity increased, while the mobility of the chain was maintained.
Comparison of the Effect of an Organoclay, Triphenylphosphate, and a Mixture of Both on the Degradation and Combustion Behaviour of PC/ABS Blends
Authors: Feyz Elham , Jahani Yousef , Esfandeh Masoud
Published: January 2011

Summary: Polycarbonate Acrylonitrile‐Butadiene‐Styrene blends (PC/ABS) with flame retardants Triphenyl Phosphate (TPP), nanoclay and their mixtures were prepared in a twin‐ screw extruder. The morphological properties were characterized by X‐ray diffractometry (XRD) which showed the intercalated structure of nanoclay in the matrix. Thermal stability of the samples was studied using Thermogravimetric Analysis (TGA), and the degradation kinetic parameters were determined using various methods including Kissinger, Flynn‐Wall‐Ozawa and Coats‐Redfern methods. It was found that the sample containing both TPP and nanoclay has the highest activation energy. The activation energy order of PC/ABS blends with different flame retardant packages, obtained by Kissinger method agrees well with that obtained by Coats‐Redfern. Cone calorimetry and limited oxygen index (LOI)/underwriters laboratory 94 (UL94) methods were used to investigate the fire behaviour and flammability of materials. The reduced mass loss rate (MLR), peak heat release rate (PHRR) and enhanced LOI of the composite containing mixture system confirmed a synergistic effect of TPP and nanoclay.
Properties and Characterization of Organoclay/Dimethacrylate Composites Obtained by In Situ Photopolymerization
Authors: Rigoli Isabel C. , Batista Tatiana , Cavalheiro Carla C. S. , Neumann Miguel G.
Published: January 2011

Summary: Composites of dimethacrylates/organoclay were obtained by in situ photopolymerization of Bis‐GMA (Bisphenol A glycidyl methacrylate) and TEGDMA (tetraethyleneglycol dimethacrylate) in the presence of camphorquinone and DEEMA (2‐(diethylamino)ethyl methacrylate). The composites contained up to 10% wt/wt of organoclays. Monomer conversion and polymerization kinetics were determined by real time Fourier‐Transform Infrared Spectroscopy – Attenuated Total Reflectance (FTIR‐ATR), and showed an increase of conversion with addition of the clay. The storage modulus E' of the composites also had a marked dependence on the composite composition and increased with addition of clay at all temperatures. Tg also increases with clay content. X‐Ray Diffraction (XRD) analysis shows that the clay is completely exfoliated for the composites with a lower proportion of clay, whereas for larger clay/polymer proportions peaks corresponding to the interlamellar distance of the clay are still observed. This is probably due to the fact that the amount of monomers in the initial formulation was not sufficient to delaminate the clay. Scanning Electron Microscopy (SEM) images indicate a quite homogenous copolymer, with some clay aggregates that increase in size and number for the higher filler loadings in agreement with the XRD results.
Synthetic Strategies to Combine High Performance Benzoxazine Thermosets with Polymers
Authors: Kiskan Baris , Yagci Yusuf
Published: January 2011

Summary: Polybenzoxazines are newly developed thermosetting polymers exhibiting versatility in a wide range of applications including electronics and aerospace industries. They exhibit highly competitive combination of properties compare to the conventional thermosets. In this paper we present synthetic strategies to incorporate thermally curable benzoxazine functions into polymers as main and side chain groups in order to further improve various properties. The strategies successfully employed include monomer synthesis, macromonomer method, polycondensation, oxidative polymerization, photo‐polymerization, click chemistry and hydrosilylation processes. In the case of macromononomer method functional initiators were used in various controlled/living polymerizations to give polymers with benzoxazine end groups. The thermal curing behaviors of the obtained polymers were also demonstrated.
Polysulfones on the Base of New Diallylaminophosphonium Salts
Authors: Gorbunova M. N. , Vorob'eva A. I.
Published: January 2011

Summary: Methods for the synthesis of new diallylaminophosphonium salts have been developed. The reactivity of tris(diethylamino)diallylaminophosphonium tetrafluoroborate (DAAP‐BF4) and chloride (DAAP‐Cl) through free‐radical copolymerization with sulfur dioxide have been studied. Diallylaminophosphonium salts do not undergo free radical homopolymerization but copolymerize at a low rate with vinyl monomers. DAAP‐BF4 and DAAP‐Cl show high activity in copolymerization with sulfur dioxide. The structure of the polysulfones obtained has been identified by NMR 13C. The investigations carried out have shown that DAAP‐BF4 and DAAP‐Cl copolymerize with sulfur dioxide, both double bonds participating with formation of cis‐, trans‐stereoisomeric pyrrolidine structures in a cyclolinear polymer chain. The new polysulfones possess a broad spectrum of bactericidal effect.
Synthesis of New Amphiphilic Comb‐Like Copolymers Based on Maleic Anhydride and α‐Olefins
Authors: Kudina Olena , Budishevska Olga , Voronov Andriy , Kohut Ananiy , Khomenko Olena , Voronov Stanislav
Published: January 2011

Summary: Novel amphiphilic comb‐like poly(α‐olefin‐co‐maleic anhydride) with a controlled ratio of hydrophilic (polyoxyethylene) and hydrophobic (polymethylene) side chains have been synthesized and characterized. The comb‐like copolymers are soluble in organic and aqueous media and form micelles whose behaviour could be correlated to the chemical structure of polymers. We foresee that amphiphilic properties of the novel comb‐like polymers are obviously the basis of new architectures in solution which could be used in a broad range of applications. Using micelles from these copolymers, silver nanoparticles with a narrow particle size distribution have been obtained as stable dispersion in both polar and non‐polar media.
Mechanical properties of blood clots – a new test method
Authors: Krasokha N. , Theisen W. , Reese S. , Mordasini P. , Brekenfeld C. , Gralla J. , Slotboom J. , Schrott G. , Monstadt H.
Published: January 2011

A blood clot needs to have the right degree of mechanical, chemical and biological properties to stem the flow of blood and yet to be suitable for lytic enzymes or mechanical thrombectomy so as not to form a thrombotic event. The origin and understanding of these mechanical properties are still not known in detail. Clots are made of a three‐dimensional network of fibrin fibers stabilized through ligation with a transglutaminase, factor XIIIa. New methods to achieve information about mechanical properties were established in this work. We performed compressive strength experiments of aged human blood clots. Furthermore after the set up of a new test environment, it was possible to perform tensile strength measurements of aged animal blood clots. Stress strain curves of aged clots were measured and discussed. The viscoelastic properties of the clot material were quantitatively described. This work should make a contribution to a better understanding of the behaviour of aged blood thrombus bulk material and induced mechanical stress.

In der Behandlung ischämischer Schlaganfälle sind mechanische, chemische und biologische Eigenschaften von Blutgerinnseln von essentieller Bedeutung und entscheidend über den Erfolg einer Lyse‐Therapie bzw. mechanischer Thrombektomie. Die Einflussfaktoren der Gerinnungsbedingungen auf die mechanischen Eigenschaften sind jedoch bisher noch nicht eingehend untersucht. Aus Schrifttum ist bekannt, dass auf mikrostruktureller Ebene die Blutgerinnsel aus Fibrinfasern, die untereinander in Knotenpunkten verbunden sind und in der Gesamtheit ein dreidimensionales Netzwerk bilden, bestehen. Dabei haben besonders die Faserdicke und die Knotenpunktendichte einen direkten Einfluss auf die mechanischen Eigenschaften eines Thrombus. Im Rahmen dieser Arbeit wurden Druck‐ und Zugversuche an Thrombus‐Proben (hergestellt aus humanem bzw. tierischem Blut) durchgeführt und die Messergebnisse hinsichtlich der Gerinnungsbedingungen diskutiert.
Stabilizing ultra‐hydrophilic surfaces by an exsiccation layer of salts and implications of the Hofmeistereffect
Authors: Jennissen H.P.
Published: January 2011

Ultra‐hydrophilic titanium surfaces can be prepared in a variety of ways by acid etching. However such surfaces are unstable in air and in water so that a storage for several years, as is necessary for clinical use, is a major problem. Ultrahydrophilic surfaces on miniplates prepared by chromosulfuric acid (CSA) enhancement showing dynamic advancing and receding contact angles of 0° (no hysteresis) can be easily stabilized and stored at room temperature in the dry state in air atmosphere. After evaporation of the aqueous phase of a salt containing solution (e. g. PBS) an exsiccation layer composed of specific ions is formed on the dry metal oxide surface exerting the stabilizing effect. The mechanism involved in this stabilizing effect of salts appears to be governed by the Hofmeister Effect. Ultra‐hydrophilic CSA (chromsulfuric acid) etched surfaces can be stabilized by an exsiccation layer for over 3 years without loss of hydrophilicity.

Ultra‐hydrophile Titanoberflächen können auf verschiedenen Wegen gewonnen werden. Diese Oberflächen verlieren jedoch sowohl in der Luft als auch in Wasser ihre ultra‐hydrophilen Eigenschaften, wodurch die Lagerung über mehrere Jahre, wie sie für Implantate notwendig ist, zum Problem wird. Ultrahydrophile Oberflächen auf Titanplättchen, die mit Chromschwefelsäure (CSA) veredelt wurden und dynamische Vorrück‐ und Rückzugswinkel von 0 Grad (keine Hysterese) aufweisen, können leicht im trockenen Zustand bei Zimmertemperatur in Luftatmosphäre stabilisiert und gelagert werden. Nach Evaporierung der wässrigen Phase einer Salzlösung (z. B. PBS) bildet sich auf der Metalloberfläche eine Exsikkationsschicht bestehend aus einer spezifischen Ionenzusammensetzung, die den stabilisierenden Effekt hervorruft. Der zugrunde liegende Mechanismus für die Stabilisierung von Exsikkationsschichten scheint im Hofmeister‐Effekt zu liegen. Ultra‐hydrophile CSA (Chromschwefelsäure) geätzte Oberflächen können durch eine Exsikkationsschicht für 3 Jahre stabilisiert und gelagert werden ohne Hydrophilizitätsverlust.
A model of market‐making with imperfect information
Authors: Hirst I. R. C.
Published: January 2011

Although the prevention of false markets is one of the major concerns of stock market authorities in the UK and elsewhere, until recently, the theoretical literature on the workings of markets with imperfect information has been sparse. This paper analyses the problem of providing liquidity to investors when price‐sensitive information is unequally distributed.

Specifically we shall model the activities of a market‐maker when certain traders have price‐sensitive information unavailable to other market participants. Our model will show how the bid‐asked spread would be determined in such a market. It is useful in explaining certain tactics employed by stock market traders and in suggesting alternative ways of evaluating market efficiency.

The theory is developed in three sections: (1) the determination of the bid‐asked spread for a single, isolated transaction; (2) the determination of the bid‐asked spread in a continuous market; (3) the relationship between the spread and the size of transaction.
Resource allocation in the nationalized energy sector of the United Kingdom
Authors: Harris D. J. , Davies B. C. L.
Published: January 2011

Resource allocation in the energy sector of the United Kingdom is a difficult area to plan, because demand and supply projections need to embrace both the large private sector oil industry and the public sector fuel industries. In addition, relationships between the latter are complex as they involve both competition and co‐ordination. One approach to the problem has been to find common ground in the concept of marginal cost pricing, but there are practical difficulties in application. Government has encouraged the use of analytical techniques, such as corporate planning, by the fuel industries as a means of co‐ordination in areas where market mechanisms may no longer always be effective.
The dominant firm with convex technology
Authors: Reid Gavin C.
Published: January 2011

The paper analyses a dominant firm model in which firms have convex production sets. The model is shown to be determinate, and to be expressible by a set of (n+1) equilibrium conditions. A previous attempt to obtain comparative statics results is criticized as being invalid, and a new framework for comparative statics is developed.
An econometric comparison of uk and german foreign holiday behaviour
Authors: Witt Stephen F.
Published: January 2011

Econometric models which explain the generation and distribution of foreign holidays undertaken by UK and German residents are constructed and estimated. These comprise the basic model, a less constrained transformation and a modified model which incorporates supply constraints and habit persistence. Both versions of the basic model are shown to exhibit a structural break across the two sets of origin data, suggesting that habit and/or supply factors are important. The empirical findings also imply that the British regard foreign holidays as luxuries whereas Germans view them as necessities.
LINGO1 gene analysis in Parkinson's disease phenotypes
Authors: Lorenzo‐Betancor Oswaldo , Samaranch Lluís , García‐Martín Elena , Cervantes Sebastián , Agúndez José A.G. , Jiménez‐Jiménez Félix J. , Alonso‐Navarro Hortensia , Luengo Antonio , Coria Francisco , Lorenzo Elena , Irigoyen Jaione , Pastor Pau ,   The Iberian Parkinson's Disease Genetics Study Group Researchers
Published: January 2011

Background: Parkinson's disease (PD) and essential tremor (ET) may share some etiopathogenic factors. A genome‐wide association study has shown that LINGO1 gene variants are associated with increased risk of ET. We hypothesized that LINGO1 variants could increase susceptibility to PD. Methods: A large series of PD subjects and healthy controls were genotyped for rs9652490 and rs11856808 LINGO1 single nucleotide polymorphisms (SNPs). Results: We found an increased frequency of the rs11856808T/T genotype in PD compared with controls (odds ratio = 1.46; corrected P value = 0.02). A recessive genetic model was the best fit for rs11856808 influence on PD (recessive gene action test: corrected P value = 0.01). Stratification analysis showed that rs11856808T/T genotype frequency was higher in the tremor‐dominant PD and the classical PD (C‐PD) subgroups (recessive gene action test for the C‐PD subgroup: corrected P value = 0.004). Discussion: Our results indicate that LINGO1 variants could increase risk of PD, specifically those presenting the non‐rigid‐akinetic phenotypes, which suggests that LINGO1 may have a role in the etiology of tremor in PD at least in the Spanish population. © 2010 Movement Disorder Society
A climate model for predicting the abundance of Aedes mosquitoes in Hong Kong
Authors: Wong M. C. , Mok H. Y. , Ma H. M. , Lee M. W. , Fok M. Y.
Published: January 2011

Aedes albopictus, which can transmit Dengue fever, is one of the common mosquitoes in Hong Kong. To study the effect of weather on the abundance of Aedes mosquitoes in Hong Kong, ovitraps were set up at an unperturbed experimental site for a period of 7 days every month to record the Ovitrap Index, an often‐adopted parameter to indicate the abundance of mosquitoes at a site, from July 2007 to June 2009. Analysis of the Ovitrap Indices at the experimental site and the weather elements collected from a nearby automatic weather station in the same period showed that the Ovitrap Indices were highly correlated with the mean air temperature over a 22 day period comprising the preceding 15 days and the 7 days when the ovitraps were in place, as well as the total rainfall over the 15 day period prior to the setting up of the ovitraps. A Climate Aedes Mosquitoes Abundance Model was developed based on the observations to predict the abundance of Aedes mosquitoes in Hong Kong. The model can provide a useful tool for planning of preventive and control measures against Aedes mosquitoes in Hong Kong. Copyright © 2010 Royal Meteorological Society
An attempt for improving MODIS atmospheric temperature profiles products in clear sky
Authors: Rahimzadegan Majid , Mobasheri M. Reza
Published: January 2011

Retrieving atmospheric temperature profile (TP) data through satellite thermal radiative measurement has gained lots of attentions in recent years. These retrieved profiles may involve some uncertainties. Although different methods have been introduced to minimize these uncertainties, they are time consuming and complicated. This work, based on the available methods, presents an approach for improving the clear sky TP calculation in two stages. In the first stage, a radiosonde mean TP is introduced to the radiation transfer equation and the deviation from this profile is calculated. In the second stage, by correcting the slope of this new profile and then using this new slope and land surface temperature, the improved TP for each pixel in the scene is calculated. A comparison between the model output TP and the one measured by radiosonde in steps of 100 m shows root mean square errors between 0.38 and 3.86 K. This shows considerable improvement compared to the Moderate Resolution Imaging Spectroradiometer (MODIS) products. Copyright © 2010 Royal Meteorological Society
Cloud detection in Meteosat Second Generation imagery at the Met Office
Authors: Hocking James , Francis Peter N. , Saunders Roger
Published: January 2011

The Met Office has been using data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board the Meteosat Second Generation (MSG) satellites for nowcasting, assimilation in numerical weather prediction (NWP) and for providing guidance to forecasters since September 2004. This paper describes the cloud mask derived from MSG imagery which is used by all downstream products. The Met Office SEVIRI mask is compared with that of the Nowcasting Satellite Applications Facility (SAFNWC), and with the Moderate Resolution Imaging Spectro‐Radiometer (MODIS) cloud mask. These comparisons show good agreement between the cloud masks: the Met Office and SAFNWC masks are in accord with the MODIS mask for 90.65% and 89.69% of SEVIRI pixels tested, respectively. © Crown Copyright 2011. Published with the permission of the Controller of HMSO and the Queen's Printer for Scotland
Analytical layer‐element method for non‐axisymmetric consolidation of multilayered soils
Authors: Ai Zhi Yong , Zeng Wen Ze
Published: January 2011

A numerically efficient and stable method is developed to analyze Biot's consolidation of multilayered soils subjected to non‐axisymmetric loading in arbitrary depth. By the application of a Laplace–Hankel transform and a Fourier expansion, the governing equations are solved analytically. Then, the analytical layer‐element (i.e. a symmetric stiffness matrix) describing the relationship between generalized displacements and stresses of a layer is exactly derived in the transformed domain. Considering the continuity conditions between adjacent layers, the global stiffness matrix of multilayered soils is obtained by assembling the inter‐related layer‐elements. Once the solution in the Laplace–Hankel transformed domain that satisfies the boundary conditions has been obtained, the actual solution can be derived by the inversion of the Laplace–Hankel transform. Finally, numerical examples are presented to verify the theory and to study the influence of the layered soil properties and time history on the consolidation behavior. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation of excavation‐induced relaxation and its application to an arch dam foundation
Authors: Chen S. H. , Wang G. J. , Zhou H. , Wang W. M. , Zou L. C.
Published: January 2011

Based on the damage mechanism of rock during excavation, the maximum tensile strain criterion for pinpointing relaxation region or excavation‐disturbed (damage) zone (EDZ) is introduced. To simulate the deformation and stress redistribution caused by the deterioration of the deformation and strength parameters in the EDZ, the ‘restraint‐relaxation’ finite element algorithm is formulated using the deformation and strength parameters of pre‐and post‐relaxation. The Xiaowan arch dam project (292 m high) is studied by the proposed method, in which the permissible tensile strain and fluidity parameter are evaluated using back analysis. The computation results have good agreement with the field monitoring. An important inference from the study is the necessity of considering the relaxation effects on the dam/foundation system during the construction and operation period. Copyright © 2011 John Wiley & Sons, Ltd.
Strain‐softening analysis of a spherical cavity
Authors: Wang Shuilin , Yin Shunde , Wu Zhenjun
Published: January 2011

This paper studies the excavation of a spherical cavity subjected to hydrostatic initial stresses in the infinite homogeneous and isotropic rock mass with strain‐softening Mohr–Coulomb (M‐C) and Hoek–Brown (H‐B) behaviors. Numerical solutions of the spherical cavity are obtained and the application to determining stress–strain curve of strain‐softening M‐C and H‐B rock mass is studied. A closed‐form solution for the elastic–brittle–plastic medium is introduced first, and then a numerical procedure that simplifies the strain‐softening process into a series of brittle–plastic ones is presented. The approach is validated against the facts that the strain‐softening process evolves into a brittle–plastic one when the softening slope is very steep, whereas it evolves into an elasto‐plastic one when the softening slope approaches zero. Numerical solutions for the prediction of displacements and stresses around the spherical cavity in the strain‐softening M‐C and H‐B rock mass are presented. On the basis of the analysis of the spherical cavity in strain‐softening rock mass, the stress–strain relationship at an infinitesimal cube around the cavity is obtained and discussed with different evolution laws for the strength parameters considered. Copyright © 2011 John Wiley & Sons, Ltd.
Rock nail reinforcement of a free surface
Authors: Papamichos Euripides , Vardoulakis Ioannis
Published: January 2011

Rock nailing of the surface instability test specimen is considered as a means to reinforce the rock and increase its free surface strength (FSS). This technique is modeled using Cox's original shear‐lag method. In the continuum sense, nail reinforcement is modeled as a body force that acts as a confinement. Results are presented for a single nail in a surface instability test specimen and for a nail‐reinforced test specimen with a given nail density. The results show that nail length and the nail–rock contact modulus are important parameters. The effect of nail reinforcement increases with the second power of nail length. Rock dilation is also important since the action of the nails is mobilized from the difference in displacement between the rock and the nail. The results show the potential for a significant increase in the FSS of the rock. Copyright © 2011 John Wiley & Sons, Ltd.
Rapid and novel prenatal molecular assay for detecting aneuploidies and microdeletion syndromes
Authors: Gross Susan J. , Bajaj Komal , Garry David , Klugman Susan , Karpel Barry M. , Marie Roe Anne , Wagner Brian J. , Zhan Jenny , Apfelroth Stephen D. , Schreiber‐Agus Nicole
Published: January 2011

Objectives

To develop a targeted aneuploidy and microdeletion detection platform for use in the prenatal setting, to assess the integrity of the platform with a robust validation system, and to prospectively determine the performance of the platform under routine clinical conditions.

Methods

To generate proxies for the various disorders assessed by the assay for analytical validation purposes, cells from ten microdeletion syndromes as well as from common aneuploidies were spiked into cleared amniotic fluid. Genomic DNA was isolated, labeled, and hybridized to microbeads that have been coupled to DNA derived from Bacterial Artificial Chromosome (BAC) from the relevant regions targeted by the array. Beads were read using a flow cytometric multiplex bead array detection system. In the prospective part of the study, 104 amniotic fluid samples were collected and analyzed.

Results

All microdeletion syndromes and aneuploidies were validated in a blinded fashion. In the prospective study, the total number of readable samples was 101 of 104 (97%). All sample results were confirmed independently.

Conclusion

The bead array approach is a rapid and reliable test for detecting aneuploidies and microdeletions. This assay has the potential to provide the benefit of expanded molecular cytogenetic testing to pregnant women undergoing invasive prenatal diagnosis. This approach may be especially useful in parts of the world where cytogenetic personnel and facilities may be limited. Copyright © 2011 John Wiley & Sons, Ltd.
Gene expression in chorionic villous samples at 11 weeks of gestation in women who develop pre‐eclampsia later in pregnancy: implications for screening
Authors: Farina Antonio , Zucchini Cinzia , De Sanctis Paola , Morano Danila , Sekizawa Akihiko , Purwosunu Yuditiya , Okai Takashi , Rizzo Nicola
Published: January 2011

Objectives

To determine the gene expression profile in chorionic villous samples (CVSs) of women destined to develop pre‐eclampsia (PE).

Method

Case‐control study encompassing five women destined to develop PE [cases matched for gestational age with 30 controls]. We quantified mRNA expression on tissue samples from CVS of normal and PE patients. We then assessed mRNA expressions of cathepsin (CTSD), angiopoietin 2 (ANGPT2), interleukin 8, chemokine (C‐X‐C motif) ligand 10, neurokinin B (NKB), matrix metallopeptidase 9, major histocompatibility complex, class I, C (HLA‐C)and human leukocyte antigen‐G (HLA‐G). Data were analyzed by nonparametric rank analysis.

Results

For all the mRNA species considered in this study, except CTSD and ANGPT2, all the mean observed ranks in the PE group were significantly altered compared with the rank expectation among controls. mRNA for NKB and HLA‐C were the markers with the highest degree of aberration in PE, compared with those in controls.

Conclusion

Our study has directly showed that gene expressions relating to trophoblastic cell invasion or utero‐placental hemodynamic adaptation are altered in the first trimester trophoblasts that go on to develop PE later. These results posit the use of residual CVS as a possible screening method for PE. Copyright © 2011 John Wiley & Sons, Ltd.
A predictive model of short cervix at 20–24 weeks using first‐trimester cervical length measurement and maternal history
Authors: Souka A. P. , Papastefanou I. , Michalitsi V. , Papadopoulos G. K. , Kassanos D.
Published: January 2011

Objectives

To develop a model for the prediction of short cervix ( ≤ 15 mm) at 20–24 weeks by combining maternal history and transvaginal ultrasonographic measurement of cervical length at 11–14 weeks. To explore the value of an additional ultrasound examination of the cervix at about 17 weeks.

Methods

Longitudinal prospective study in 800 unselected pregnant women presenting for first‐trimester ultrasound assessment by nuchal translucency and serum biochemistry. Cervical length was evaluated transvaginally between 11 weeks and 13 weeks and 6 days (cx1), at 16–19 weeks (cx2) and 20–24 weeks (cx3). Backward multiple logistic regression analysis with cx3 ≤ 15 mm as the dependent variable was used to identify the predictors of a short cervix at 20–24 weeks.

Results

Cx1 and history of preterm delivery were significant independent contributors of a short cervix at 20–24 weeks [area under the curve (AUC 0.808, p < 0.001, Model) 1]. Furthermore, the cx1/cx2 ratio was a significant independent predictor of a short cervix at 20–24 weeks (odds ratio = 58.325 p = 0.012). The addition of the cx1/cx2 ratio improved the model (AUC = 0.878, p < 0.001, Model 2).

Conclusions

A short cervix at 20–24 weeks can be predicted at the 11–14 weeks scan. The addition of a cervical measurement at about 17 weeks can improve the prediction model. Copyright © 2011 John Wiley & Sons, Ltd.
Increasing off‐label use of antipsychotic medications in the United States, 1995–2008
Authors: Alexander G. C. , Gallagher S. A. , Mascola A. , Moloney R. M. , Stafford R. S.
Published: January 2011

Objective

To evaluate patterns of antipsychotic use.

Design, setting, and measurements

We used nationally representative data from the IMS Health National Disease and Therapeutic Index to describe outpatient antipsychotic use. The primary outcome was the volume of visits where antipsychotics were used for specific indications (treatment visits). We also quantified use without U.S. Food and Drug Administration approval (off‐label use) and off‐label use with compendium data suggesting an uncertain evidence base.

Results

Antipsychotic use increased from 6.2 million (M) treatment visits (95% CI, 5.4–7.0) in 1995 to 16.7 M visits (15.5–18.2) in 2006, then declined to 14.3 M visits (13.0–15.6) by 2008. A shift occurred from typical agents in 1995 (84% of all antipsychotic visits) to atypical agents by 2008 (93%). As they declined, typical medications shifted toward use in schizophrenia (30% in 1995 to 48% 2008). In contrast, use of atypical agents expanded for bipolar affective disorder (10 to 34%), remained stable for depression (12 to 14%), and declined for schizophrenia (56 to 23%). Overall, antipsychotic use for indications without FDA approval increased from 4.4 M visits in 1995 to 9.0 M in 2008. The estimated cost associated with off‐label use in 2008 was US$6.0 billion.

Conclusions

Atypical use has grown far beyond substitution for the now infrequently used typical agents. Antipsychotics are increasingly used for conditions where FDA approval and associated clinical evidence is less certain. Despite the value of innovation, the benefits of widening atypical antipsychotic use should be weighed against their cost, regulatory status, and incomplete nature of available evidence. Copyright © 2011 John Wiley & Sons, Ltd.
Equal‐channel multiangular extrusion of semicrystalline polymers
Authors: Beloshenko V.A. , Varyukhin V.N. , Voznyak A.V. , Voznyak Yu.V.
Published: January 2011

Potentialities of a new simple shear‐based scheme of the solid‐phase extrusion of polymers, named the equal channel multiple angular extrusion (ECMAE), for modification of semicrystalline polymer structure have been investigated by the example of low‐ and high‐density polyethylene (LDPE, HDPE), polyamide‐6 (PA‐6), and polytetrafluoroethylene (PTFE). The effects of velocity and extrusion temperature, plastic deformation intensity, and accumulated equivalent plastic strain value on properties of a number of crystallizing polymers have been studied. It has been shown that the highest strength characteristics are attained for the extrusion temperatures of (0.8–0.95) of the melting temperature and deformation velocity of (0.6–1.1) mm s−1. For the ECMAE‐processed specimens, the density, the enthalpy, and the melting temperature have become higher. In the oriented structure of semicrystalline polymers formed by the ECMAE, the lamellae are oriented along the extrudate axis. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
In silico discovery and experimental validation of new protein–protein interactions
Authors: van Haagen Herman H. H. B. M. , 't Hoen Peter A. C. , de Morrée Antoine , van Roon‐Mom Willeke M. C. , Peters Dorien J. M. , Roos Marco , Mons Barend , van Ommen Gert‐Jan , Schuemie Martijn J.
Published: January 2011

We introduce a framework for predicting novel protein–protein interactions (PPIs), based on Fisher's method for combining probabilities of predictions that are based on different data sources, such as the biomedical literature, protein domain and mRNA expression information. Our method compares favorably to our previous method based on text‐mining alone and other methods such as STRING. We evaluated our algorithms through the prediction of experimentally found protein interactions underlying Muscular Dystrophy, Huntington's Disease and Polycystic Kidney Disease, which had not yet been recorded in protein–protein interaction databases. We found a 1.74‐fold increase in the mean average prediction precision for dysferlin and a 3.09‐fold for huntingtin when compared to STRING. The top 10 of predicted interaction partners of huntingtin were analysed in depth. Five were identified previously, and the other five were new potential interaction partners. The full matrix of human protein pairs and their prediction scores are available for download. Our framework can be extended to predict other types of relationships such as proteins in a complex, pathway or related disease mechanisms.
Global identification of miR‐373‐regulated genes in breast cancer by quantitative proteomics
Authors: Yan Guang‐Rong , Xu Song‐Hui , Tan Zi‐Lu , Liu Langxia , He Qing‐Yu
Published: January 2011

Although microRNAs (miRNAs) have been reported to play an important role in carcinogenesis, their molecular mechanism remains largely unknown because of our limited understanding of miRNA target genes. miR‐373 was found to be capable of promoting breast cancer invasion and metastasis, but only a target gene was experimentally identified on the basis of mRNA expression analysis. In this study, we used SILAC‐based quantitative proteomics to globally identify the genes regulated by miR‐373. Totally, 3666 proteins were identified, and 335 proteins were found to be regulated by miR‐373. Among the 192 proteins that were downregulated by miR‐373, 27 (14.1%) were predicted to have at least one potential match site at their 3′‐UTR for miR‐373 seed sequence. However, miR‐373 did not affect the mRNA level of the five selected candidate targets, TXNIP, TRPS1, RABEP1, GRHL2 and HIP1, suggesting that the protein expressions were regulated by miR‐373 via translational inhibition instead of mRNA degradation. Luciferase and mutation assays validated that TXNIP and RABEP1 were the direct target genes of miR‐373. More than 30 proteins reported to be involved in cancer invasion and metastasis were found to be regulated by miR‐373 in breast cancer for the first time.
Visualize: A free and open source multifunction tool for proteomics data analysis
Authors: Halligan Brian D. , Greene Andrew S.
Published: January 2011

A major challenge in the field of high‐throughput proteomics is the conversion of the large volume of experimental data that is generated into biological knowledge. Typically, proteomics experiments involve the combination and comparison of multiple data sets and the analysis and annotation of these combined results. Although there are some commercial applications that provide some of these functions, there is a need for a free, open source, multifunction tool for advanced proteomics data analysis. We have developed the Visualize program that provides users with the abilities to visualize, analyze, and annotate proteomics data; combine data from multiple runs, and quantitate differences between individual runs and combined data sets. Visualize is licensed under GNU GPL and can be downloaded from http://proteomics.mcw.edu/visualize. It is available as compiled client‐based executable files for both Windows and Mac OS X platforms as well as PERL source code.
The good, the bad, the ugly: Validating the mass spectrometric analysis of modified peptides
Authors: Beck Florian , Lewandrowski Urs , Wiltfang Matthias , Feldmann Ingo , Geiger Jörg , Sickmann Albert , Zahedi René Peiman
Published: January 2011

Mass spectrometric characterization of protein modifications is usually based on single peptides. With the advent of large‐scale PTM‐focussed MS studies, vast amounts of data are generated continuously, providing biologists extremely valuable and virtually never‐ending sources for targeted functional research. However, even more than for proteomics in general, appropriate strategies for quality control of the different steps of the analytical strategy are imperative to prevent functional researchers from doing Sisyphos work on false‐positive and unconfident PTM assignments. Here, we describe strategies to address the important issue of quality control for PTM analysis on various levels of the analytical pipeline: sample preparation/processing, analysis/identification and finally data interpretation, for qualitative as well as quantitative studies.
Folding determinants of disulfide bond forming protein B explored by solution nuclear magnetic resonance spectroscopy
Authors: Hwang Soyoun , Hilty Christian
Published: January 2011

The two‐stage model for membrane protein folding postulates that individual helices form first and are subsequently packed against each other. To probe the two‐stage model, the structures of peptides representing individual transmembrane helices of the disulfide bond forming protein B have been studied in trifluoroethanol solution as well as in detergent micelles using nuclear magnetic resonance (NMR) and circular dichroism spectroscopy. In TFE solution, peptides showed well‐defined α‐helical structures. Peptide structures in TFE were compared to the structures of full‐length protein obtained by X‐ray crystallography and NMR. The extent of α‐helical secondary structure coincided well, lending support for the two‐stage model for membrane protein folding. However, the conformation of some amino acid side chains differs between the structures of peptide and full‐length protein. In micellar solution, the peptides also adopted a helical structure, albeit of reduced definition. Using measurements of paramagnetic relaxation enhancement, peptides were confirmed to be embedded in micelles. These observations may indicate that in the native protein, tertiary interactions additionally stabilize the secondary structure of the individual transmembrane helices. Proteins 2011. © 2011 Wiley‐Liss, Inc.
New insights into the GABAA receptor structure and orthosteric ligand binding: Receptor modeling guided by experimental data
Authors: Sander Tommy , Frølund Bente , Bruun Anne Techau , Ivanov Ivaylo , McCammon James Andrew , Balle Thomas
Published: January 2011

GABAA receptors (GABAARs) are ligand gated chloride ion channels that mediate overall inhibitory signaling in the CNS. A detailed understanding of their structure is important to gain insights in, e.g., ligand binding and functional properties of this pharmaceutically important target. Homology modeling is a necessary tool in this regard because experimentally determined structures are lacking. Here we present an exhaustive approach for creating a high quality model of the α1β2γ2 subtype of the GABAAR ligand binding domain, and we demonstrate its usefulness in understanding details of orthosteric ligand binding. The model was constructed by using multiple templates and by incorporation of knowledge from biochemical/pharmacological experiments. It was validated on the basis of objective energy functions, its ability to account for available residue specific information, and its stability in molecular dynamics (MD) compared with that of the two homologous crystal structures. We then combined the model with extensive structure‐activity relationships available from two homologous series of orthosteric GABAAR antagonists to create a detailed hypothesis for their binding modes. Excellent agreement with key experimental data was found, including the ability of the model to accommodate and explain a previously developed pharmacophore model. A coupling to agonist binding was thereby established and discussed in relation to activation mechanisms. Our results highlight the importance of critical evaluation and optimization of each step in the homology modeling process. The approach taken here can greatly aid in increasing the understanding of GABAARs and related receptors where structural insight is limited and reliable models are difficult to obtain. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Domain structure of magnetic nanotube with transverse anisotropy
Authors: Usov N. A. , Zhukov A. , González J.
Published: January 2011

The magnetic properties of soft magnetic nanotubes with a transverse anisotropy are investigated by means of numerical simulation. The structure of isolated bamboo domain wall and its evolution under the influence of axial uniform magnetic field, as well as a circular magnetic field of a DC current is investigated. Also the stability of various bamboo domain structures (BDS) in axial and circular magnetic fields is studied. It is found that the magnetic field that saturates a nanotube in axial direction is close to the anisotropy field. On the other hand, the interval of circumferential magnetic fields where a BDS can exist is two orders of magnitudes shorter.
Absorption spectra of azobenzenes simulated with time‐dependent density functional theory
Authors: Jacquemin Denis , Preat Julien , Perpète Eric A. , Vercauteren Daniel P. , André Jean‐Marie , Ciofini Ilaria , Adamo Carlo
Published: January 2011

Using time‐dependent density functional theory and the polarizable continuum model, we have simulated the absorption spectra of an extended series of azobenzene dyes. First, we have determined a theoretical level optimal for this important class of dyes, and it turned out that a C‐PCM‐CAM‐B3LYP/6‐311+G(d,p)//C‐PCM‐B3LYP/6‐311G(d,p) approach represents an effective compromise between chemical accuracy and computational cost. In a second stage, we have compared the theoretical and experimental transition energies for 46 n → π☆ and 141 π → π☆ excitations. For the full set, that spans over a 302–565 nm domain, we obtained a mean absolute deviation of 13 nm (0.10 eV) and a linear correlation coefficient of 0.95, illustrating the accuracy of our approach, though some significant outliers pertained. In a last step, the impact of several modifications, that is, trans/cis isomerization, variation of the acidity of the medium and azo/hydrazo tautomerism have been modeled with two functionals. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010