bluuebunny/crossref_metadata_2025_split huggingface dataset:
Patient and tumor factors at diagnosis in a multi‐ethnic primary head and neck squamous cell carcinoma cohort
Authors: Sethi Seema , Lu Mei , Kapke Alissa , Benninger Michael S , Worsham Maria J 
Published: November 2008

AbstractBackgroundA long‐term objective is to refine patient diagnosis and prognosis to address heterogeneity in head and neck squamous cell carcinoma (HNSCC) through incorporation of patient and tumor factors. This study examined histopathology and demographic variables at primary diagnosis (early vs. late stage) in a HNSCC patient population with a higher than usual percentage of African American (AA) subjects.MethodsThe primary HNSCC cohort was drawn from a diverse patient population and constructed through re‐review of the primary biopsy. Nine specific histopathology and patient factors (race, gender, age) at primary HNSCC diagnosis were evaluated. Logistic regression analyses incorporated univariate and multivariable modeling.ResultsRace, gender, pattern of invasion, tumor necrosis, perineural invasion, site, and tumor grade were included in the first multivariable model. The final multivariable model retained gender, race, grade, site, and perineural invasion as independent risk factors for late stage with goodness‐of‐fit, the area under the curve (AUC), as 0.691.ConclusionsThis report emphasizes patient and tumor characteristics of race, gender, site, perineural invasion, grade, and pattern of invasion as independent factors of advanced stage HNSCC. Pattern of invasion and necrosis are also important tumor characteristics of late stage disease. These factors may offer clinical perspectives when evaluating patients with indeterminate stage. J. Surg. Oncol. 2009;99: 104–108. © 2008 Wiley‐Liss, Inc.
Stable transgene expression in human embryonic stem cells after simple chemical transfection
Authors: Liu Jun , Jones Karen L. , Sumer Huseyin , Verma Paul J. 
Published: November 2008

AbstractIn this study we used plasmid‐based vectors to investigate the transcriptional activities of three commonly used promoters in transient and stable transfection of MEL‐1, a human embryonic stem (ES) cell line, using ExGen500, Fugene HD, and Lipofectamine. We demonstrated that cytomegalovirus (CMV), phosphoglycerate kinase (PGK) and human elongation factor‐1α (EF1α) promoters all resulted in robust activity of a reporter gene in MEL‐1 ES cell transient transfections regardless of the transfection reagent. Stable transfection outcomes varied, depending on the promoter and the transfection reagent used in the study. The phenomenon of transgene silencing was observed, most notably with the CMV vector, with which no positive stably transfected clones were obtained. Of the methods used in the study, Fugene HD resulted in the highest stable transfection rate, estimated by antibiotic selection, with plasmids containing genes under the control of the EF1α or PGK promoters. Stably transfected cells maintained typical hES cell morphology, with immunostaining exhibiting expression of the hES cell markers: Oct4, SSEA4, Tra‐1‐60, and Tra‐1‐81. Further, embryoid bodies formed by suspension culture retained reporter gene expression. Following injection into immunodeficient mice, the transfected cell lines showed robust formation of teratomas with cell types representative of the three germ layers. Mol. Reprod. Dev. 76: 580–586, 2009. © 2008 Wiley‐Liss, Inc.
Bearing capacity factor Nc under ϕ=0 condition for piles in clays
Authors: Khatri Vishwas N. , Kumar Jyant 
Published: November 2008

AbstractBearing capacity factor Nc for axially loaded piles in clays whose cohesion increases linearly with depth has been estimated numerically under undrained (ϕ=0) condition. The study follows the lower bound limit analysis in conjunction with finite elements and linear programming. A new formulation is proposed for solving an axisymmetric geotechnical stability problem. The variation of Nc with embedment ratio is obtained for several rates of the increase of soil cohesion with depth; a special case is also examined when the pile base was placed on the stiff clay stratum overlaid by a soft clay layer. It was noticed that the magnitude of Nc reaches almost a constant value for embedment ratio greater than unity. The roughness of the pile base and shaft affects marginally the magnitudes of Nc. The results obtained from the present study are found to compare quite well with the different numerical solutions reported in the literature. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of bladder outlet obstruction on α1‐ and β‐adrenoceptor expression and function
Authors: Barendrecht Maurits M. , Frazier Elfaridah P. , Vrydag Wim , Alewijnse Astrid E. , Peters Stephan L.M. , Michel Martin C. 
Published: November 2008

AbstractAimsTo explore possible changes in expression and/or function of α1‐ and β‐adrenoceptor subtypes as a cause for bladder dysfunction in a rat model of bladder outlet obstruction (BOO).MethodsBOO was induced in rats by partial urethral ligature. Contraction and relaxation experiments were performed with isolated bladder strips from BOO, sham‐operated and non‐operated (control) rats 7 days after BOO induction. mRNA expression of α1‐ and β‐adrenoceptor subtypes was assessed by quantitative real‐time PCR.ResultsReceptor‐independent contraction or relaxation did not differ between BOO and sham rats. The α1‐agonists methoxamine and A‐61,603 caused only weak contraction without major differences between groups. Against KCl‐induced tone, the β‐adrenoceptor agonists noradrenaline and isoprenaline caused similar relaxation in BOO and sham rats, whereas relaxation in response to the β3‐selective BRL 37,344 was attenuated. Against passive tension, noradrenaline induced relaxation in sham and control rats; in contrast, noradrenaline induced contraction at low concentrations and relaxation at high concentrations in BOO rats. The contraction component was abolished by the α1‐antagonist prazosin. The mRNA expression of α1D‐adrenoceptors was increased in BOO, whereas none of the other receptor mRNAs were up‐regulated.ConclusionsIn a rat BOO model, weak contraction responses to α1‐agonists and relaxation responses to β‐agonists are not altered to a major extent. Nevertheless, relaxation responses to the endogenous agonist noradrenaline are turned into α1‐adrenoceptor‐mediated contraction responses in BOO, possibly due to an up‐regulation of α1D‐adrenoceptors. Neurourol. Urodynam. 28:349–355, 2009. © 2008 Wiley‐Liss, Inc.
Effect of paramagnetic manganese cations on 1H MRS of the brain
Authors: Madsen Kathrine Skak , Holm David Alberg , Søgaard Lise Vejby , Rowland Ian J. 
Published: November 2008

AbstractManganese cations (Mn2+) can be used as an intracellular contrast agent for structural, functional and neural pathway imaging applications. However, at high concentrations, Mn2+ is neurotoxic and may influence the concentration of 1H MR‐detectable metabolites. Furthermore, the paramagnetic Mn2+ cations may also influence the relaxation of the metabolites under investigation. Consequently, the purpose of this study was to investigate the effect of paramagnetic Mn2+ cations on 1H‐MR spectra of the brain using in vivo and phantom models at 4.7 T. To investigate the direct paramagnetic effects of Mn2+ cations on the relaxation of N‐acetylaspartate (NAA), creatine and choline, T1 relaxation times of metabolite solutions, with and without 5% albumin, and containing different Mn2+ concentrations were determined. Relaxivity values with/without 5% albumin for NAA (4.8/28.1 s−1 mM−1), creatine (2.8/2.8 s−1 mM−1) and choline (1.8/1.1 s−1 mM−1) showed NAA to be the most sensitive metabolite to the relaxation effects of the cations. Using an in vivo optic tract tracing imaging model, we obtained two adjacent regions of interest in the superior colliculi with different water T1 values (Mn2+‐enhanced = 1.01 s; unenhanced = 1.14 s) 24 h after intravitreal injection of 3 µL 50 mM MnCl2. Using phantom and in vivo water relaxation time data, we estimated the in vivo Mn2+ concentration to be 2–8 µM. The phantom data suggest that limited metabolite relaxation effects would be expected at this concentration. Consequently, this study indicates that, in this model, the presence of Mn2+ cations does not significantly affect 1H‐MR spectra despite possible toxic and paramagnetic effects. Copyright © 2008 John Wiley & Sons, Ltd.
An optimal‐order estimate for MMOC‐MFEM approximations to porous medium flow
Authors: Wang Kaixin 
Published: November 2008

AbstractMathematical models used to describe porous medium flow lead to coupled systems of time‐dependent partial differential equations. Standard methods tend to generate numerical solutions with nonphysical oscillations or numerical dispersion along with spurious grid‐orientation effect. The MMOC‐MFEM time‐stepping procedure, in which the modified method of characteristics (MMOC) is used to solve the transport equation and a mixed finite element method (MFEM) is used for the pressure equation, simulates porous medium flow accurately even if large spatial grids and time steps are used. In this article we prove an optimal‐order error estimate for a family of MMOC‐MFEM approximations. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
Characterization of twin‐screw‐extruder‐compounded polycarbonate nanoclay composites
Authors: Nevalainen Katja , Vuorinen Jyrki , Villman Vesa , Suihkonen Reija , Järvelä Pentti , Sundelin Janne , Lepistö Toivo 
Published: November 2008

AbstractPolycarbonate nanocomposites were prepared by melt processing from two surface‐modified montmorillonite organoclays. The intercalation spacing and degree of the dispersion were characterized with wide‐angle X‐ray diffraction and transmission electron microscopy, respectively. The polycarbonate nancomposites showed rather good dispersion of nanoclay, with a mixture of exfoliated, intercalated, and confined morphology. The effect of nanoclay on the mechanical response of specimens subjected to tensile and impact loading was investigated. Results demonstrated that nanocomposites based on nanoclay possess increased Young's modulus and yield strength. However, their ductility upon tensile loading is significantly affected. A transition from ductile to brittle deformation occurs at studied clay loadings. Notched impact strength experiments supported this, showing that impact strength decreases significantly as nanoclay content increases from 1 to 5 wt%, regardless how the nanoclay surface was modified. Thermal analysis demonstrated that addition of nanoclay leads to decreased thermal stability of polycarbonate suggesting, enhanced dynamics of polymer chains. Finally, the tribological properties of selected specimens were evaluated using a pin‐on‐disc, and the effect of nanoclay fillers on tribological properties is discussed. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Specific interactions in ternary system quaternized polysulfone/mixed solvent
Authors: Filimon Anca , Avram Ecaterina , Ioan Silvia 
Published: November 2008

AbstractTheoretical and experimental aspects on the specific interactions developed via electrostatic interactions and hydrogen‐bonding in a ternary system formed of a proton‐donor solvent (N,N‐dimethylformamide or methanol), a proton‐acceptor solvent (water), and a quaternized polysulfone with various contents of ionic chlorine, which indicates a proton‐acceptor character, are investigated. Thus, the interactions of the ternary systems are corrected on the basis of the association phenomena defined through association constants. Numerical values for these constants were evaluated as a function of the system composition, by mathematical simulations for an accurate adjustment of preferential adsorption, determined by the Flory–Huggins–Pouchly theoretical approach applied to the experimental data. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Orientated crystallization in drawn thermoplastic polyimide modified by carbon nanofibers
Authors: Smirnova Valentina E. , Gofman Iosif V. , Yudin Vladimir E. , Dobrovolskaya Irina P. , Shumakov Alexander N. , Didenko Andrey L. , Svetlichnyi Valentine M. , Wachtel Ellen , Shechter Rinat , Harel Hannah , Marom Gad 
Published: November 2008

AbstractThe solid state crystallization in drawn thermoplastic polyimide films is studied as a function of draw ratio (DR) under the effect of vapor grown carbon fiber nanoinclusions. The nucleating effect of the nanoinclusions coupled with the orientation effect of drawing generates a unique orientated layered lamellar structure, characteristic of smectic‐like mesophase. The degree of draw induced orientated crystallization increases with the content of nanoinclusions and with the DR, and is reflected in the mechanical behavior of the film. Generally, the Young's modulus and the yield point of the drawn crystalline films in the drawing direction are significantly higher compared with the noncrystalline counterparts. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Poly(methacrylic acid)‐modified chitosan for enhancement adsorption of water‐soluble cationic dyes
Authors: Xing Yun , Sun Xiaomei , Li Buhai 
Published: November 2008

AbstractThe preparation of poly(methacrylic acid)‐modified chitosan microspheres and its application for the removal of cationic dyes, methylene blue (MB) and malachite green (MG), in aqueous solution in a batch system were described. The modified chitosan was characterized using SEM, FTIR, and XPS analyses. The effects of the pH of the solution, contact time, and initial dye concentration were studied. The adsorption capacities of the microspheres for the two cationic dyes increased significantly after the modification because a large number of carboxyl groups were introduced. The equilibrium process was better described by the Langmuir than the Freundlich isotherm. According to the Langmuir equation, the maximum adsorption capacities were 1000.0 and 523.6 mg g−1 for MB and MG, respectively. Kinetic studies showed better correlation coefficients for a pseudo‐second‐order kinetic model, confirming that the sorption rate was controlled by a chemisorption process. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Influences of blend proportions and curing systems on dynamic, mechanical, and morphological properties of dynamically cured epoxidized natural rubber/high‐density polyethylene blends
Authors: Nakason Charoen , Jarnthong Methakarn , Kaesaman Azizon , Kiatkamjornwong Suda 
Published: November 2008

AbstractThermoplastic elastomers (TPEs) based on dynamically cured epoxidized natural rubber/high‐density polyethylene (ENR/HDPE) blends were prepared. Influence of the process oil, blend proportion, and curing systems were investigated. It was found that the oil‐extended thermoplastic vulcanizates (TPVs) exhibited better elastomeric properties and improved ease of the injection process. Increasing the proportion of ENR caused increasing elastic response of elongation at break, tension set properties, and tan δ. It was also found that the TPV treated with phenolic resin exhibited superior mechanical properties and the smallest vulcanized rubber domains. The TPV treated with the conventional peroxide co‐agent curing system showed superior strength properties but had poor elastomeric properties. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Relationships among optimism, well‐being, self‐transcendence, coping, and social support in women during treatment for breast cancer
Authors: Matthews Ellyn E. , Cook Paul F. 
Published: November 2008

AbstractObjective: The impact of diagnosis and treatment for breast cancer, stressors that affect emotional well‐being, is influenced by several psychosocial factors and the relationships among them. The purpose of this study was to investigate the relationship between optimism and emotional well‐being (EWB) and the individual and combined mediation of this relationship by perceived social support (SS), problem focused coping (PFC), and self‐transcendence in women with breast cancer during radiation therapy.Methods: Ninety‐three women receiving radiation treatment for breast cancer completed questionnaires that measured EWB, optimism, SS, PFC, and self‐transcendence.Results: Correlational and multiple regression analysis revealed that optimism was positively related to EWB. Of the three mediators, self‐transcendence alone was found to partially mediate the relationship between optimism and EWB. The relationship between optimism and PFC was not significant. Optimism was related to SS, but its indirect effect on EWB through SS did not reach significance.Conclusions and implications: During breast cancer treatment, the positive effects of optimism on EWB are partially mediated by a woman's level of self‐transcendence. Brief screening of women's optimism may help identify women at risk for psychological distress. Early detection and interventions to promote psychological adjustment throughout the cancer trajectory (e.g. enhancing self‐transcendence) should receive attention in future research. Copyright © 2008 John Wiley & Sons, Ltd.
Strain effect on polarized optical properties of c ‐plane GaN and m ‐plane GaN
Authors: Tao Renchun , Yu Tongjun , Jia Chuanyu , Chen Zhizhong , Qin Zhixin , Zhang Guoyi 
Published: November 2008

AbstractThe polarized optical property of c ‐plane and m ‐plane GaN with varying strain was discussed by analyzing the changes of relative oscillator strength (ROS) of the three transitions related to the top three valence bands. The ROS was calculated by applying the effective‐mass Hamiltonian based on k · p perturbation theory. For c ‐plane GaN, it was found that ROS of |X 〉 state and |Y 〉 state were superposed with each other. Especially, they increased with compressive strain, while that of |Z 〉 decreased in the second band. For m ‐plane GaN under compressive strain, the first three bands were dominated by |X 〉, |Z 〉 and |Y 〉 states, respectively, which led to nearly linearly‐polarized light emissions. With compressive strain, the ROS of |X 〉 state increased more rapidly than |Z 〉 state in the topmost valence band. As a result, TE mode emissions from both c ‐plane and m ‐plane GaN increased more rapidly than TM mode emission with compressive strain, leading to larger polarization degree. Experimental results of luminescences from InGaN/GaN quantum wells showed good coincidence with our theoretical calculations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of nitrogen incorporation on surface properties of silicon oxynitride films
Authors: Hong Jongin , Kim Yunseok , Paik Hanjong , No Kwangsoo , Lukes Jennifer R. 
Published: November 2008

AbstractIn order to investigate the surface heterogeneity of silicon oxynitride films, we observed the nanoscale variation of the surface potential by Kelvin probe force microscopy (KFM), the molecular bonding characteristics by Fourier transform infrared spectrometry (FTIR), and the wetting behavior by contact angle measurement. Nitrogen incorporation into silicon oxynitride films influenced the decrease in the surface potential and the polar component of the surface free energy. We present the first correlation between the nanoscale measurement of the surface potential and the macroscopic measurement of the surface free energy in silicon oxynitride films grown by a standard plasma‐enhanced chemical vapor deposition (PECVD) technique. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The derivation of a numerical diagnostic model for the forcing of the geopotential
Authors: Yuan Zhuojian , Wu Junjie , Cheng Xuhua , Jian Maoqiu 
Published: November 2008

AbstractSimply applying the divergence operator to the horizontal velocity equation in spherical‐isobaric coordinates yields a more solvable linear geopotential equation (than the geopotential tendency and the omega equations) for diagnosing the geopotential and its anomalies responsible for global floods and droughts. This geopotential model is freed from the zero‐denominator problem caused by the observed neutral stability which affects the geopotential tendency and omega equations. The geopotential equation's forcing terms 2–5 (the direct operation results of the horizontal advection term in the velocity equation) can identify the synoptic signals mixed up by the classical divergence equation's quadratic and Jacobian terms (the manipulated results of the above terms 2–5). Solving this geopotential equation with the successive‐over‐relaxation method and the neutral stability as calculated from the reanalysis data produces reasonably good reconstructions of the global and local geopotential fields. The additional advantages of the present geopotential model over the geopotential tendency, omega and divergence models are that the geopotential model reveals and explains the following mechanisms which received less attention in previous studies. (1) The saddle patterns favour the high systems. (2) The equatorial easterlies favour the low systems. (3) The contributions of ageostrophic processes associated with jets and saddle flows to the transitions of weather patterns might be overlooked by the geopotential tendency model in which neutral stability and static instability in cold domes as well as jet‐induced inertial instability are smoothed out artificially. Copyright © 2008 Royal Meteorological Society
Bonding and correlation analysis of various Si2CO isomers on the potential energy surface
Authors: Zhou Zhong‐Jun , Liu Hui‐Ling , Yu Jian‐Kang , Yu Guang‐Tao , Huang Xu‐Ri 
Published: November 2008

AbstractAt various levels of theory, singlet and triplet potential energy surfaces (PESs) of Si2CO, which has been studied using matrix isolation infrared spectroscopy, are investigated in detail. A total of 30 isomers and 38 interconversion transition states are obtained at the B3LYP/6‐311G(d) level. At the higher CCSD(T)/6‐311+G(2d)//QCISD/6‐311G(2d)+ZPVE level, the global minimum 11 (0.0 kcal/mol) corresponds to a three‐membered ring singlet O‐cCSiSi (1A′). On the singlet PES, the species 12 (0.2 kcal/mol) is a bent SiCSiO structure with a 1A′ electronic state, followed by a three‐membered ring isomer Si‐cCSiO (1A′) 13 (23.1 kcal/mol) and a linear SiCOSi 14 (1Σ+) (38.6 kcal/mol). The isomers 11, 12, 13, and 14 possess not only high thermodynamic stabilities, but also high kinetic stabilities. On the triplet PES, two isomers 31 (3B2) (18.8 kcal/mol) and 37 (3A″) (23.3 kcal/mol) also have high thermodynamic and kinetic stabilities. The bonding natures of the relevant species are analyzed. The similarities and differences between C3O, C3S, SiC2O, and SiC2S are discussed. The present results are also expected to be useful for understanding the initial growing step of the CO‐doped Si vaporization processes. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Are the Hirshfeld and Mulliken population analysis schemes consistent with chemical intuition?
Authors: Saha Soumen , Roy Ram Kinkar , Ayers Paul W. 
Published: November 2008

AbstractIn the present article, we report a comparative study between the Hirshfeld and Mulliken population analysis schemes (abbreviated as HPA and MPA, respectively). Trends of atomic charges derived from these two population analysis schemes are compared with those expected from other commonly used chemical concepts like electronegativity, inductive effects, and resonance effects. Although previous studies on intramolecular reactivity sequences demonstrated that HPA generates reliable and non‐negative (and thus physically more realistic) condensed Fukui function (FF) values, the present study reveals problems with the HPA charge partitioning technique. Specifically, HPA fails to reproduce reliable intermolecular and intramolecular charge trends in several systems. Reasons for the success and failure of HPA are discussed and a method for improving the Hirshfeld charge partitioning is proposed. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009