bluuebunny/crossref_metadata_2025_split huggingface dataset:
Region‐specific changes in ascorbate concentration during rat brain development quantified by in vivo1H NMR spectroscopy
Authors: Terpstra Melissa , Rao Raghavendra , Tkac Ivan 
Published: August 2010

AbstractAscorbate (vitamin C, Asc) was quantified in vivo using short‐TE 1H NMR spectra from a previously published study on regional and developmental changes in the neurochemical profile of the rat brain (Tkac I, Rao R, Georgieff MK, Gruetter R. Magn Reson Med. 2003; 50: 24–32). Asc concentration was quantified on postnatal days P7–P28 from three regions that are of interest in the study of neurocognitive development, i.e. the hippocampus, striatum and cerebral cortex. The previously measured 1H NMR spectra were re‐analyzed using LCModel with the Asc spectrum included in the basis set. The Asc concentration was consistently quantified from all 110 re‐analyzed spectra with an estimated fitting error of 7% (i.e. the average Cramer–Rao lower bound). The sensitivity of Asc quantification was sufficiently high to detect regional and developmental changes in Asc concentration. The concentration of Asc was highest on P7, and decreased with age in all three brain regions (p < 0.001) in agreement with previous in vitro studies. At P10 and older postnatal ages, an inhomogeneous distribution of Asc among brain regions was detected. In addition to facilitating the quantification of this important antioxidant concentration, the inclusion of the Asc spectrum in the LCModel basis set improved the quantification accuracy of other brain metabolite concentrations in the neurochemical profile. Copyright © 2010 John Wiley & Sons, Ltd.
Tumour‐infiltrating T‐cell subsets, molecular changes in colorectal cancer, and prognosis: cohort study and literature review
Authors: Nosho Katsuhiko , Baba Yoshifumi , Tanaka Noriko , Shima Kaori , Hayashi Marika , Meyerhardt Jeffrey A , Giovannucci Edward , Dranoff Glenn , Fuchs Charles S , Ogino Shuji 
Published: August 2010

AbstractThe abundance of tumour‐infiltrating T‐cells has been associated with microsatellite instability (MSI) and a favourable prognosis in colorectal cancer. However, numerous molecular alterations have been associated with clinical outcome, and potentially confounding the biological and prognostic significance of tumour‐infiltrating T‐cells. We utilized a database of clinically and molecularly‐annotated colon and rectal carcinoma cases (N = 768; stage I–IV) in two prospective cohort studies (the Nurses' Health Study and the Health Professionals Follow‐up Study) and quantified the densities of CD3+, CD8+, CD45RO+ (PTPRC), and FOXP3+ cells within neoplastic epithelial areas using an Ariol image analysis system and tissue microarray. We used Cox proportional hazard models to compute the mortality hazard ratio, adjusting for clinical and molecular features including KRAS, BRAF, and PIK3CA mutations, MSI, CIMP, and LINE‐1 hypomethylation. The densities of CD8+, CD45RO+, and FOXP3+ cells were significantly associated with patient survival in univariate analyses ($p_{\rm{trend}} < 0.007$). In the multivariate model, tumour‐infiltrating CD45RO+‐cell density, but not CD3+, CD8+ or FOXP3+‐cell density, was significantly associated with survival (p = 0.0032). In multivariate linear regression analysis, MSI‐high (p < 0.0001) and high‐level tumour LINE‐1 methylation (p = 0.0013) were independently associated with higher CD45RO+‐cell density. The survival benefit associated with CD45RO+ cells was independent of MSI and LINE‐1 status. In conclusion, tumour‐infiltrating CD45RO+‐cell density is a prognostic biomarker associated with longer survival of colorectal cancer patients, independent of clinical, pathological, and molecular features. In addition, MSI‐high and tumour LINE‐1 methylation level are independent predictors of CD45RO+‐cell density. Our data offer a possible mechanism by which MSI confers an improved clinical outcome and support efforts to augment the host immune response in the tumour microenvironment as a strategy of targeted immunotherapy. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Hydrogenated nitrile butadiene rubber and hindered phenol composite. I. Miscibility and dynamic mechanical property
Authors: Cao Yuanyi , Shen Fei , Mou Haiyan , Cao Deming , Xu Haiyan , Wu Chifei 
Published: August 2010

AbstractIn this study, miscibility and dynamic mechanical properties of hydrogenated nitrile butadiene rubber (HNBR) and 3,9‐bis{1,1‐dimethyl‐2‐[β‐(3‐tert‐butyl‐4‐hydroxy‐5‐methylphenyl) propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) composites were investigated. The composites with low‐AO‐80 content showed the incomplete miscibility, and a part of AO‐80 dissolved into HNBR, while the rest was dispersed into HNBR in the form of deep‐submicron‐sized microspheres based on the micromorphological and thermal analyses. However, with the increasing AO‐80 content, the system became completely miscible. When blending with AO‐80, the resulting composite exhibited the remarkably improved dynamic mechanical property. The loss tangent (tan δ) peak of the composites gradually shifted to room temperature with the increasing AO‐80 content. In this work, two classical equations (Gorden‐Taylor and Fox) were used to predict the glass transition temperature of the HNBR/AO‐80 composites. The calculated value based on Fox equation was more close to the experimental data. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Microstructure morphology of poly(trimethylene terephthalate)/amorphous poly(ethylene terephthalate) blends studied via small angle X‐ray scattering
Authors: Chiu Hsiu‐Jung 
Published: August 2010

AbstractThe microstructure morphology of the poly(trimethylene terephthalate) (PTT) and amorphous poly(ethylene terephthalate) (aPET) blends prepared by solution precipitation has been investigated by means of optical polarized microscopy (POM) and small angle X‐ray scattering (SAXS). From the observation of POM, it was suggested that aPET was predominantly segregated into the interlamellar and/or interfibrillar regions upon PTT crystallization with the evidence that the PTT spherulitic morphologies of blends were volume filling. From results of SAXS data analysis, the maximum scattering peak (qmax) of Lorentz‐corrected SAXS profiles, amorphous layer thickness (la) and lamellar volume stacking fraction (ϕs), the segregation morphology of PTT/aPET blends is characterized to be the interlamellar segregation morphology when the weight friction of aPET (waPET) ≤ 0.2 and the interlamellar and interfibrillar segregation coexisted when waPET > 0.2. The extent of aPET segregation was promoted by increasing aPET composition. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Solid‐state microcellular polycarbonate foams. II. The effect of cell size on tensile properties
Authors: Weller John E. , Kumar Vipin 
Published: August 2010

AbstractThe effect of cell size on the tensile behavior of high‐relative‐density microcellular polycarbonate foams is investigated. Microcellular PC foams were produced in a way that allowed the average cell size to be varied, while the foam density was held constant. The polycarbonate‐CO2 system offers an order of magnitude variation in the average cell size at a given density, allowing the tensile properties of microcellular polycarbonate to be investigated as a function of cell size. It was found that the tensile modulus, tensile strength, elongation to break, and toughness are not significantly affected when the average cell size is varied from 2.8 to 37.1 μm, and the nominal relative density is held constant at 0.5. This result is significant for solid‐state processing of microcellular polycarbonate foams of the type produced here, for it shows that regardless of the processing conditions and regardless of the average cell size, if two foams have the same density then they will also have the same tensile properties. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Influence of the process parameters of an intermeshing co‐rotating twin screw extruder on the morphology and notched Izod impact strength of PBT/ABS/MGE blends
Authors: Ambrósio José D. , Larocca Nelson M. , Pessan Luiz A. , Hage Elias 
Published: August 2010

AbstractIn this research, it was studied the effects of the processing parameters applied to a twin screw extruder on the morphology and impact strength of poly(butylene terephthalate)/acrylonitrile‐butadiene‐styrene blends with and without a reactive compatibilizer. It was found that the increase of the feed rate highly decreased the ductile brittle transition temperature (DBTT) and slightly increased the room temperature impact strength (RTIS) of the compatibilized blends. Besides the influence of the feed rate, it was also found that the compatibilized blends could reach high RTIS and low DBTT values by an appropriate combination of the compatibilizer feeding position in the extruder, the screw rotation speed and the width of the kneading discs of the screw. The DBTT was found to be at least partially controlled by the spatial distribution of the rubbery particles, which was quantified by finite body tessellation, a method applied for the first time in polymer blends. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Mechanical and water vapor transport properties of polyurethane/superfine down powder composite membranes
Authors: Liu Xin , Xu Weilin , Li Wenbin , Chen Yubo , Rao Jue 
Published: August 2010

AbstractTo develop a novel microporous polyurethane (PU) membrane that has higher water vapor transmission rate (WVTR) for use in functional application, down powder with different average particle sizes was blended with PU by using the solution casting method. Scanning electron microscope was used to investigate the changes in the porous structures of PU/superfine down powder (SDP) composite membranes. Attenuated total reflectance Fourier transform infrared spectroscopy curves showed that the addition of SDP decreased the hydrogen bonds of PU matrix. On the basis of wide‐angle X‐ray diffraction curves, the small crystallinity of the PU matrix in PU/SDP composite membranes was lower than that of pure PU membrane. The densities of PU/SDP composite membranes decreased with the increase in SDP content. PU/SDP composite membranes showed a large increase in WVTR and a small decrease in mechanical properties compared to pure PU membrane. Moreover, the WVTR and mechanical properties of PU/down powder composite membranes were found absolutely dependent on the average particle size of down powder. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Nanocellular foams—cell structure difference between immiscible and miscible PEEK/PEI polymer blends
Authors: Nemoto Tomoyuki , Takagi Jun , Ohshima Masahiro 
Published: August 2010

AbstractPlastic foam with a nanoscale cell structure was prepared from poly(ether ether ketone) (PEEK)/para‐diamine poly(ether imide) (p‐PEI) as well as PEEK/meta‐diamine poly(ether imide) (m‐PEI) blends by a temperature quench foaming method with CO2. The difference in chemical configuration between m‐ and p‐PEI gave rise to a prominent change in the higher order blend morphology and cell structure of the respective foams. The bubble nucleation site and bubble size were controlled by templating the morphology of the PEEK/p‐PEI blend, which shows an immiscible and unique strip‐patterned crystalline morphology. The properties influenced by the immiscibility of the PEEK/p‐PEI blend were investigated using SEM, thermal analysis and rheology and compared with the properties of the miscible PEEK/m‐PEI blend. The bubble size and location were highly controlled in the PEI disperse domain that was aligned between the PEEK crystalline layers in the PEEK/p‐PEI blend. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Splashing needleless electrospinning of nanofibers
Authors: Tang Shan , Zeng Yongchun , Wang Xinhou 
Published: August 2010

AbstractThis article proposes a new needleless electrospinning apparatus applying the method of splashing polymer solution onto the surface of a metal roller spinneret. When a high voltage is applied, many spinning jets form on the free surface of polymer solutions. Multiple electrified jets undergo strong stretching and bending instability, solvent evaporates, and solidified nanofibers deposit on the collector, as in an ordinary single‐needle electrospinning process. The production of nanofibers is enhanced by 24–45 times comparing with a single‐needle system. And the productivity is easy to scale up. The effects of processing parameters, including solution concentration, applied voltage, distance between spinneret to collector, and rotational speed of the roller spinneret on the morphology of nanofibers are investigated in this article. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
Analysis of polymer flow in embossing stage during thermal nanoimprint lithography
Authors: Kim S.M. , Kang J.H. , Lee W.I. 
Published: August 2010

AbstractViscous polymer flow in embossing stage during thermal nanoimprint lithography was investigated. Flow behavior of the thermoplastic polymer was analyzed numerically and experimentally. Fixed grid scheme along with the finite element method was used for numerical analysis. Effects of process parameters such as the temperature, the stamp speed, and the stamp geometry on the filling pattern for single cavity were studied. Also the patterns with several cavities were analyzed to understand the flow behavior between adjacent cavities. Experiments were performed using PMMA sheets to confirm the effects of parameters obtained from numerical analyses. Two different types of geometries were considered and the filled patterns were observed using a scanning electron microscopy. Numerical results exhibited a similar tendency as the experimental observation. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers
Plasma Deposited Organosilicon Multistacks for High‐Performance Low‐Carbon Steel Protection
Authors: Coclite Anna Maria , Milella Antonella , Palumbo Fabio , Le Pen Christophe , d'Agostino Riccardo 
Published: August 2010

AbstractThe alternated deposition of silicon oxide and organosilicon layers, yielding to ultra‐barrier films against the transmission of vapors and gases through plastic substrates, has been demonstrated to be also an effective tool for the deposition of highly corrosion protective coatings on low‐carbon steel substrate. PECVD is really efficient for the deposition of multilayered stacks since it allows the deposition of the organosilicon and silicon oxide layers in the same process chamber and using the same precursor, the tetraethoxysilane. The multilayer approach leads to 600‐nm‐thick coatings with high corrosion resistance (1.1 × 107 Ωcm2), while a layer of SiOx has the same protective effectiveness only for thickness greater than 1 µm. The use of modulated discharges for the multilayer deposition exhibits an improved resistance to corrosion by two orders of magnitude with respect to continuous mode.magnified image
One Step Polymerization of Sulfonated Polystyrene Films in a Dielectric Barrier Discharge
Authors: Merche Delphine , Hubert Julie , Poleunis Claude , Yunus Sami , Bertrand Patrick , De Keyzer Philippe , Reniers François 
Published: August 2010

AbstractThin sulfonated polystyrene films were prepared by high pressure PECVD of styrene and trifluoromethane sulfonic acid using a DBD. Argon or helium was used as carrier gas. The chemical composition of the pp‐sulfonated polystyrene was investigated by XPS, SSIMS, and FTIR. XPS shows that the content in sulfonated groups of the films deposited in the discharge can be tuned by varying the temperature of the acid monomer or by improving the HF voltage. Therefore, the films obtained are rich in ionizable groups (more than Nafion). TOF‐SSIMS and FTIR spectra allow to confirm the presence of sulfonic groups (observed on S2p XPS spectra) grafted in the polystyrene matrix.magnified image
Potential anti‐bacterial drug target: Structural characterization of 3,4‐dihydroxy‐2‐butanone‐4‐phosphate synthase from Salmonella typhimurium LT2
Authors: Kumar Pankaj , Singh Mirage , Gautam Ruchi , Karthikeyan Subramanian 
Published: August 2010

Abstract3,4‐Dihydroxy‐2‐butanone‐4‐phosphate synthase (DHBPS) encoded by ribB gene is one of the first enzymes in riboflavin biosynthesis pathway and catalyzes the conversion of ribulose‐5‐phosphate (Ru5P) to 3,4‐dihydroxy‐2‐butanone‐4‐phosphate and formate. DHBPS is an attractive target for developing anti‐bacterial drugs as this enzyme is essential for pathogens, but absent in humans. The recombinant DHBPS enzyme of Salmonella requires magnesium ion for its activity and catalyzes the formation of 3,4‐dihydroxy‐2‐butanone‐4‐phosphate from Ru5P at a rate of 199 nmol min−1 mg−1 with Km value of 116 μM at 37°C. Further, we have determined the crystal structures of Salmonella DHBPS in complex with sulfate, Ru5P and sulfate‐zinc ion at a resolution of 2.80, 2.52, and 1.86 Å, respectively. Analysis of these crystal structures reveals that the acidic loop (residues 34–39) responsible for the acid‐base catalysis is disordered in the absence of substrate or metal ion at the active site. Upon binding either substrate or sulfate and metal ions, the acidic loop becomes stabilized, adopts a closed conformation and interacts with the substrate. Our structure for the first time reveals that binding of substrate Ru5P alone is sufficient for the stabilization of the acidic active site loop into a closed conformation. In addition, the Glu38 residue from the acidic active site loop undergoes a conformational change upon Ru5P binding, which helps in positioning the second metal ion that stabilizes the Ru5P and the reaction intermediates. This is the first structural report of DHBPS in complex with either substrate or metal ion from any eubacteria. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Measurement of DNA denaturation on B‐NCD coated diamond micro‐cantilevers
Authors: Bongrain A. , Uetsuka H. , Rousseau L. , Valbin L. , Saada S. , Gesset C. , Scorsone E. , Lissorgues G. , Bergonzo P. 
Published: August 2010

AbstractWe report the detection of DNA denaturation using diamond micro‐cantilevers operating in dynamic mode in liquid environment. Intrinsic diamond cantilevers were fabricated using a bottom up approach which consists of a selective growth of diamond patterns in micro‐machined silicon moulds. They were then coated with a thin layer of boron doped diamond to allow electrochemical immobilization of DNA on their surface. DNA was attached onto the measuring cantilever using a four‐step electrochemical process involving diazonium salt grafting on diamond surface. The DNA immobilization was validated by cyclic voltammetry and fluorescence imaging. DNA denaturation was detected by comparing the resonance frequency shift of the measuring diamond cantilever against that of a reference cantilever when adding the denaturing agent in the solution. A frequency shift was measured and was attributed to surface stress modification upon denaturation.
On the development of the morphology of ultrananocrystalline diamond films
Authors: Kulisch Wilhelm , Popov Cyril , Sasaki Takao , Sirghi Lucel , Rauscher Hubert , Rossi Francois , Reithmaier Johann Peter 
Published: August 2010

AbstractThe development of the unique morphology of ultrananocrystalline diamond (UNCD) films has been investigated by varying three important parameters which are expected to have a pronounced influence on the morphology and structure of any thin film, namely the deposition time, the growth rate, and the nucleation density. The films have been characterized, among others, by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), nuclear reaction analysis and variable angle ellipsometry. It turned out, however, that the morphology and the rms roughness are almost independent of these parameters. Growth starts from individual nucleation sites created by the substrate pre‐treatment. From these sites individual isolated semispherical nodules develop which finally coalesce to form a continuous film. Once coalescence has taken place, the films loose their “memory” of their nucleation history. Rather, morphology and roughness are solely determined by the rate of secondary nucleation, which is very high and distinguishes UNCD from poly‐ and nanocrystalline diamond films.
Transport in carbon nanotubes: Contact models and size effects
Authors: Zienert Andreas , Schuster Jörg , Streiter Reinhard , Gessner Thomas 
Published: August 2010

AbstractWe present electronic transport calculations for single wall carbon nanotubes (CNTs) using two highly idealized models to describe the electrodes and their contact to the CNT. In the first model we use CNT‐electrodes and in the second one we apply the wide‐band approximation, neglecting any atomic structure within the electrodes. The single orbital tight‐binding approximation is used to describe the electronic structure of the CNTs. This enables us to apply highly efficient decimation techniques to reduce the size of the finite central Hamiltonian. Semi‐infinite CNT‐electrodes can be included iteratively using a similar method. Electronic transport calculations are carried out within the Landauer formalism.
Ab initio calculations of weakly bonded He2 and Be2 molecules by MRCI method with pseudo‐natural molecular orbitals
Authors: Mitin Alexander V. 
Published: August 2010

AbstractThe X1Σ curves of He2 and Be2 have been calculated by extrapolating the BSSE corrected MRCI total energies obtained with large Gaussian basis sets, large reference configuration spaces, and pseudo‐natural molecular orbitals to an infinite basis. The direct calculated He2 nonrelativistic dissociation energies (De) of 11.0031 K is in excellent agreement with the recent theoretical evaluations, whereas the Be2 nonrelativistic De = 822 cm−1 and relativistically corrected De = 818 cm−1 are in good agreement with most known values including the experimental De = 790 ± 30 cm−1. An analysis of the configuration structure of Be2 wave function and calculated vibration spectrum displays unusual type of chemical bond in this molecule and explains a unique form of the Be2 potential curve. Thus, near the equilibrium point the bond can be classified as a conventional covalent bond, whereas at larger distances, it can be classified as van der Waals interaction. The problems of high precision Be2 potential curve calculations are also discussed. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Magnetic neutron scattering anti‐Bragg solution
Authors: Zagoulaev Serge N. 
Published: August 2010

AbstractA new solution for the elastic spin magnetic scattering of slow neutrons by a N‐electron target is obtained. The angular dependence of the differential cross section (DCS) has very unusual (anti‐Bragg) shape for a target, which degenerate ground state has zero z ‐projection (M = 0) of the total spin. Contrary to usual assumption that neutron is scattered by each atomic spin independently, the scattering by the whole target spin system is considered. The many‐electron many‐determinant wave functions Ψa(x1,…,xN) (xj ≡rjσj) are used for analytical calculations of the scattering amplitude. The total spin square eigenfunctions ΘϰS0(σ1,…,σN) have been used for the spin part of Ψa . Explicit analytical expressions for the DCS are obtained and the initial and final neutron polarization effects are discussed. It is shown that the regular pattern of the anti‐Bragg diffraction has no relation to the periodic magnetization of the target. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011