bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life satisfaction of Swedish pediatric oncologists: The role of personality, work‐related aspects, and emotional distress
Authors: Stenmarker Margaretha , Palmérus Kerstin , Márky Ildikó 
Published: August 2009

AbstractBackgroundThe first nationwide, population‐based study of Swedish pediatric oncologists was conducted in 2006 and it revealed that various aspects of their life satisfaction obviously influenced their stress‐resilience. This second part of the study, with a response rate of 89% in the target group, therefore, focused on their life satisfaction and the role of personality, work‐related aspects, and emotional distress related to type of medical center and gender.ProcedureThis descriptive study was based on a cross‐sectional mail survey with questionnaires involving 90 pediatric oncologists. Using hierarchical regression models, their total, present, past, and future life satisfaction was analyzed.ResultsThe vast majority (76.7%) stated that working in this medical field was very stimulating for their personal development. Male pediatricians were more satisfied with their present lives and physicians working at academic medical centers were more confident about the future. Some oncologists (13.4%), in particular females at non‐academic medical centers, needed professional help dealing with work‐related psychological problems. Personality trait (Hedonic Capacity) and low levels of depression contributed to every aspect of overall life satisfaction. Work‐related aspects influenced present and future life satisfaction. The models explained between 5% and 43% of the variance in life satisfaction in the whole group.ConclusionsPediatric oncologists face life‐threatening conditions and psychosocial issues factors that may negatively influence their life satisfaction. This study group, a single population of physicians, is characterized by an optimistic attitude and stable emotional status pointing to a high level of satisfaction, which is probably a main basic condition when meeting seriously ill children. Pediatr Blood Cancer 2009; 53:1308–1314. © 2009 Wiley‐Liss, Inc.
Impact of radiation attenuation and temperature evolution on monomer conversion of dimethacrylate‐based resins with a photobleaching photoinitiator
Authors: Mucci Veronica , Cook Wayne D. , Vallo Claudia 
Published: August 2009

AbstractThe photopolymerization process of a dimethacrylate copolymer system activated by the camphorquinone (CQ)/amine photoinitiator system (1 wt%), was experimentally studied under nonisothermal conditions in 1‐ and 2‐mm thick samples by measuring double bond conversion, temperature rise and radiation attenuation through the sample during polymerization. The peak temperature in 1‐ or 2‐mm thick samples irradiated at 5 mW/cm2 was 29 and 38°C, respectively. The temperature evolution during polymerization was also predicted by solving the energy balance coupled with the kinetic expressions for the reaction rate. Radiation attenuation as a function of depth by the photobleachable CQ results in spatial and temporal variation in the local rates of the kinetic steps involved. General relationships for spatiotemporal variations in concentration of a photobleaching initiator, in systems where attenuation and initiator consumption are taken into account, were used to compute local polymerization rates. The effects of radiation attenuation, photobleaching of the photoinitiator and variation of cure temperature at different depths into the resin, all compete to determine the double bond consumption. The increased radiation attenuation in the 2‐mm thick sample was accompanied by a higher cure temperature compared with the 1‐mm thick sample, and as a result, the monomer conversion averaged over the sample thickness in the 1‐ and 2‐mm thick samples was the same. Results obtained in this research highlight the inherent interlinking of thermal and radiation attenuation effects in bulk photopolymerizing systems. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
The influence of processing parameters on fingering formation in fluid‐assisted injection‐molded disks
Authors: Lin Kun‐Yeh , Liu Shih‐Jung 
Published: August 2009

AbstractOne of the problems encountered in fluid‐assisted injection‐molded parts is the gas or water “fingering” phenomenon, in which gas (water) bubbles penetrate nonuniformly into the core of the parts and form finger‐shape branches. Severe fingerings can lead to significant reductions in part stiffness. This study investigated the fingering phenomenon in fluid‐assisted injection‐molded disk parts. Experiments were carried out on a reciprocating injection‐molding machine equipped with gas‐ and water‐injection units. The material used was virgin polypropylene. A disk cavity with two different thicknesses was used for all experiments. The effects of various processing parameters on the fingering were examined. It was found that the melt short shot size and mold temperature were the principal parameters affecting the formation of part fingerings. In addition, the formation mechanism of part fingerings has also been proposed to better understand the formation of part fingerings. It has been shown that the fluid‐assisted filling process is an unstable system by nature. Any small perturbation by material viscosity or by temperature gradient can trigger the unbalance of gas (water) penetrations in the parts and result in fingerings. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Toughening effects of ethylene–vinyl acetate copolymers with different vinyl acetate content and viscosity on nylon 1010 blends
Authors: Yu Haiyang , Zhang Yong , Ren Wentan 
Published: August 2009

AbstractNylon 1010 blends with ethylene–vinyl acetate copolymer (EVA) and maleated ethylene–vinyl acetate (EVA‐g‐MAH) were prepared through melt blending. The vinyl acetate (VA) content and viscosity of EVA significantly affected the notched impact strength of nylon/EVA/EVA‐g‐MAH (80/15/5) blends. The nylon/EVA/EVA‐g‐MAH blends with high notched impact strength (over 60 kJ/m2) were obtained when the VA content in EVA ranged from 28 to 60 wt%. The effect of VA content on the notched impact strength of blends was related to the glass transition temperature for EVA with high VA content and crystallinity for EVA with low VA content. For nylon blends with EVA with the same VA content, low viscosity of EVA led to high notched impact strength. Fracture morphology of nylon/EVA/EVA‐g‐MAH (80/15/5) blends showed that blends with ductile fracture behavior usually had large matrix plastic deformation, which was the main energy dissipation mechanism. A relationship between the notched impact strength and the morphology of nylon/EVA/EVA‐g‐MAH (80/15/5) blends was well correlated by the interparticle distance model. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Structure, crystallization behavior, and thermal stability of PP/MCM‐41 nanocomposite
Authors: Wang Na , Fang Qinghong , Chen Erfan , Zhang Jing , Shao Yawei 
Published: August 2009

AbstractThe structure, crystallization, and thermal stability of polypropylene containing nanosized MCM‐41 particle, whose pore channels were filled with polystyrene inside the pore channels with the aid of supercritical CO2, were investigated by X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analyses, respectively. The results of differential scanning calorimetry showed that the incorporation of MCM‐41 (without template) increased the melting temperature and the crystallization temperature by approximately 7 and 1.8°C, respectively. Although the incorporation of MCM‐41 (with template) and MCM‐41‐S‐PS decreased the melting temperature, the crystallization temperature and the crystallization rate increased. The result of crystallization kinetics showed dramatic increase in crystallization rate and decrease in t1/2 and tf for PP/MCM‐41 (without template) nanocomposite, whereas decrease in crystallization rate and increase in t1/2 and tf for PP/MCM‐41 (with template) and PP/MCM‐41‐S‐PS nanocomposites. The thermal results indicated that the thermal stability of the composite was enhanced by addition of all nanoparticles. At the 95% weight loss, adding 2.5 wt% nanomaterial, the decomposition temperature of PP/MCM‐41‐S‐PS was 50.71°C higher than that of PP, 13.98°C higher than that of PP/MCM‐41 (without template), and 0.39°C higher than that of PP/MCM‐41 (with template). POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
A neck‐in model in extrusion lamination process
Authors: Shiromoto Seiji , Masutani Yasushi , Tsutsubuchi Masaaki , Togawa Yoshiaki , Kajiwara Toshihisa 
Published: August 2009

AbstractIn this study, the experiment of the extrusion lamination process using high‐pressure process low‐density polyethylene (LDPE) was performed. The nonisothermal viscoelastic simulation of the extrusion lamination experiment was also carried out. The simulation results were in good agreement with the experimental data within wide range of take up velocity and air gap length. We developed the theoretical model based on force balance and deformation type of a film to predict the neck‐in behavior in the extrusion lamination or cast film process. It was suggested from the neck‐in model that the neck‐in correlates with the ratio of planar to uniaxial elongational viscosity. It was confirmed that the neck‐in model could predict the film edge shape and neck‐in properly for conventional LDPE. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Flow pattern variations of viscoelastic fluid flows in three‐dimensional branching channel
Authors: Yamaguchi Hiroshi , Zhang Xin‐Rong , Matsumoto Tomoko 
Published: August 2009

AbstractTransport phenomena in three‐dimensional branching channel are important because of their relevance in polymer processing. In this article, an experimental study on viscoelastic flow in a three‐dimensional cylindrical branching channel is carried out to investigate variations of flow pattern. Flow visualization in representative symmetric planes is made both for the viscoelastic fluid and Newtonian flow. From the results of the present investigation, the flow field in the three‐dimensional cylindrical branching channel is clarified within the range of laminar flow. It is confirmed that corner vortex, shedding vortex, and secondary vortex flow are all obviously changed with the fluid concentration and the Reynolds number, which are much more three‐dimensional and complex than the Newtonian fluid, and the flow pattern of the viscoelastic fliud flow largely depends on the Reynolds number and fluid concentration. Even for the viscoelastic flow at the low Reynolds number, shedding vortex and secondary vortex and complex three‐dimensional flow occur in the cylinder. The flow field is not symmetric space for the viscoelastic flow and however is fairly symmetric for the Newtonian fluid. The above reasons explain why the flow deflection happens even at the low Reynolds number flow. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Plasma Polymerization of HMDSO with an Atmospheric Pressure Plasma Jet for Corrosion Protection of Aluminum and Low‐Adhesion Surfaces
Authors: Lommatzsch Uwe , Ihde Jörg 
Published: August 2009

AbstractThin functional films were deposited on aluminum with an atmospheric pressure plasma jet using hexamethyldisiloxane (HMDSO) as precursor. A high dynamic deposition rate on the order of 450 nm · m · min−1 was achieved. Composition and structure of the thin films show a strong dependence on the downstream location of the precursor injection. A 4 mm downstream shift of the precursor injection increases the carbon content in the thin film by a factor of 2.5, as indicated by XPS analysis and alters the degree of cross‐linking according to the FTIR spectra. The coating with the low carbon content (17 at.‐%) provides corrosion resistance for aluminum 2024 unclad exposed for 96 h to a neutral salt spray test. The coating with the high carbon content reduces the adhesion of an epoxy resin to the surface and may be used as a release coating.magnified image
A binding free energy decomposition approach for accurate calculations of the fidelity of DNA polymerases
Authors: Rucker Robert , Oelschlaeger Peter , Warshel Arieh 
Published: August 2009

AbstractDNA polymerase β (pol β) is a small eukaryotic enzyme with the ability to repair short single‐stranded DNA gaps that has found use as a model system for larger replicative DNA polymerases. For all DNA polymerases, the factors determining their catalytic power and fidelity are the interactions between the bases of the base pair, amino acids near the active site, and the two magnesium ions. In this report, we study effects of all three aspects on human pol β transition state (TS) binding free energies by reproducing a consistent set of experimentally determined data for different structures. Our calculations comprise the combination of four different base pairs (incoming pyrimidine nucleotides incorporated opposite both matched and mismatched purines) with four different pol β structures (wild type and three mutants). We generate three fragments of the incoming deoxynucleoside 5′‐triphosphate‐TS and run separate calculations for the neutral base part and the highly charged triphosphate part, using different dielectric constants in order to account for the specific dielectric response. This new approach improves our ability to predict the effect of matched and mismatched base pairing and of mutations in DNA polymerases on fidelity and may be a useful tool in studying the potential of DNA polymerase mutations in the development of cancer. It also supports our point of view with regards to the origin of the structural control of fidelity, allowing for a quantified description of the fidelity of DNA polymerases. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Active and inactive state structures of unliganded Lactobacillus casei allosteric L‐lactate dehydrogenase
Authors: Arai Kazuhito , Ishimitsu Toshihiro , Fushinobu Shinya , Uchikoba Hiroyuki , Matsuzawa Hiroshi , Taguchi Hayao 
Published: August 2009

AbstractLactobacillus casei
L‐lactate dehydrogenase (LCLDH) is activated through the homotropic and heterotropic activation effects of pyruvate and fructose 1,6‐bisphosphate (FBP), respectively, and exhibits unusually high pH‐dependence in the allosteric effects of these ligands. The active (R) and inactive (T) state structures of unliganded LCLDH were determined at 2.5 and 2.6 Å resolution, respectively. In the catalytic site, the structural rearrangements are concerned mostly in switching of the orientation of Arg171 through the flexible intersubunit contact at the Q‐axis subunit interface. The distorted orientation of Arg171 in the T state is stabilized by a unique intra‐helix salt bridge between Arg171 and Glu178, which is in striking contrast to the multiple intersubunit salt bridges in Lactobacillus pentosus nonallosteric L‐lactate dehydrogenase. In the backbone structure, major structural rearrangements of LCLDH are focused in two mobile regions of the catalytic domain. The two regions form an intersubunit linkage through contact at the P‐axis subunit interface involving Arg185, replacement of which with Gln severely decreases the homotropic and hetertropic activation effects on the enzyme. These two regions form another intersubunit linkage in the Q‐axis related dimer through the rigid NAD‐binding domain, and thus constitute a pivotal frame of the intersubunit linkage for the allosteric motion, which is coupled with the concerted structural change of the four subunits in a tetramer, and of the binding sites for pyruvate and FBP. The unique intersubunit salt bridges, which are observed only in the R state structure, are likely involved in the pH‐dependent allosteric equilibrium. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Structure of the ribosome associating GTPase HflX
Authors: Wu Hao , Sun Lei , Blombach Fabian , Brouns Stan J.J. , Snijders Ambrosius P. L. , Lorenzen Kristina , van den Heuvel Robert H. H. , Heck Albert J. R. , Fu Sheng , Li Xuemei , Zhang Xuejun C. , Rao Zihe , van der Oost John 
Published: August 2009

AbstractThe HflX‐family is a widely distributed but poorly characterized family of translation factor‐related guanosine triphosphatases (GTPases) that interact with the large ribosomal subunit. This study describes the crystal structure of HflX from Sulfolobus solfataricus solved to 2.0‐Å resolution in apo‐ and GDP‐bound forms. The enzyme displays a two‐domain architecture with a novel “HflX domain” at the N‐terminus, and a classical G‐domain at the C‐terminus. The HflX domain is composed of a four‐stranded parallel β‐sheet flanked by two α‐helices on either side, and an anti‐parallel coiled coil of two long α‐helices that lead to the G‐domain. The cleft between the two domains accommodates the nucleotide binding site as well as the switch II region, which mediates interactions between the two domains. Conformational changes of the switch regions are therefore anticipated to reposition the HflX‐domain upon GTP‐binding. Slow GTPase activity has been confirmed, with an HflX domain deletion mutant exhibiting a 24‐fold enhanced turnover rate, suggesting a regulatory role for the HflX domain. The conserved positively charged surface patches of the HflX‐domain may mediate interaction with the large ribosomal subunit. The present study provides a structural basis to uncover the functional role of this GTPases family whose function is largely unknown. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Morphology of self‐assembled structures formed by short peptides from the amyloidogenic protein tau depends on the solvent in which the peptides are dissolved
Authors: Chaudhary Nitin , Singh Shashi , Nagaraj Ramakrishnan 
Published: August 2009

AbstractThe aggregation behavior of peptides Ac‐VQIVYK‐amide (AcPHF6) and Ac‐QIVYK‐amide (AcPHF5) from the amyloidogenic protein tau was examined by atomic force microscopy (AFM) and fluorescence microscopy. Although AcPHF5 did not show enhancement of thioflavin T (ThT) fluorescence in aqueous buffer, distinct aggregates were discernible when peptide was dissolved in organic solvents such as methanol (MeOH), trifluoroethanol (TFE), and hexafluoroisopropanol (HFIP) dried on mica and examined by AFM. Self‐association was evident even though the peptide did not have the propensity to form secondary structures in the organic solvents. In dried films, the peptide adopts predominantly β‐conformation which results in the formation of distinct aggregates. ThT fluorescence spectra and fluorescence images indicate the formation of fibrils when AcPHF6 solutions in organic solvents were diluted into buffer. AcPHF6 had the ability to organize into fibrillar structures when AFM samples were prepared from peptide dissolved in MeOH, TFE, HFIP, and also when diluted into buffer. AcPHF6 showed propensity for β‐structure in aqueous buffer. In MeOH and TFE, AcPHF6 showed helical and β‐structure. Morphology of the fibrils was dependent on peptide conformation in the organic solvents. The structures observed for AcPHF6 are formed rapidly and long incubation periods in the solvents are not necessary. The structures with varying morphologies observed for AcPHF5 and AcPHF6 appear to be mediated by surfaces such as mica and the organic solvents used for dissolution of the peptides. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
An improvement of quantum parametric methods by using SGSA parameterization technique and new elementary parametric functionals
Authors: Sánchez M. , Oldenhof M. , Freitez J. A. , Mundim K. C. , Ruette F. 
Published: August 2009

AbstractA systematic improvement of parametric quantum methods (PQM) is performed by considering: (a) a new application of parameterization procedure to PQMs and (b) novel parametric functionals based on properties of elementary parametric functionals (EPF) [Ruette et al., Int J Quantum Chem 2008, 108, 1831]. Parameterization was carried out by using the simplified generalized simulated annealing (SGSA) method in the CATIVIC program. This code has been parallelized and comparison with MOPAC/2007 (PM6) and MINDO/SR was performed for a set of molecules with CC, CH, and HH bonds. Results showed better accuracy than MINDO/SR and MOPAC‐2007 for a selected trial set of molecules. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Magnetic interactions and electronic structure of uvarovite and andradite garnets. An ab initio all‐electron simulation with the CRYSTAL06 program
Authors: Meyer A. , Pascale F. , Zicovich‐Wilson C. M. , Dovesi R. 
Published: August 2009

AbstractThe ground‐state electronic structure of a number of magnetic phases of the garnets andradite (Ca3Fe2Si3O12) and uvarovite (Ca3Cr2Si3O12) has been investigated at the density functional theory level of approximation using the periodic ab initio code CRYSTAL. An all‐electron Gaussian‐type basis has been used in conjunction with the B3LYP hybrid functional. The exchange coupling constants between the first (J1a and J1b differentiating the two nonidentical sites), second (J2), and third (J3) nearest neighbors have been evaluated and are found to be in good agreement with the experimental data that is available for andradite. As a consequence of both the different J1a to J1b ratio and the opposite sign of J2 in the two minerals, different antiferromagnetic (AF) ground states are found for uvarovite and andradite, which is in agreement with experimental observation. Strong support for the additivity and transferability of the J constants is provided by calculations in which Cr and Fe ions are embedded in the related grossular structure. The mechanism for the stabilization of the AF states is discussed within the Anderson theory of superexchange; the kinetic energy gain in the AF states is calculated, and the spin density maps and profiles are examined. Density of states, charge density maps, and Mulliken population data complete the analysis of the electronic structure. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
How many‐body perturbation theory (MBPT) has changed quantum chemistry
Authors: Kutzelnigg Werner 
Published: August 2009

AbstractThe history of many‐body perturbation theory (MBPT) and its impact on Quantum Chemistry is reviewed, starting with Brueckner's conjecture of a linked‐cluster expansion and the time‐dependent derivation by Goldstone of such an expansion. A central part of this article is the time‐independent formulation of quantum chemistry in Fock space and its diagrammatic representation including the particle‐hole picture and the inversion of a commutator. The results of the time‐independent derivation of MBPT are compared with those of Goldstone. It is analyzed which ingredients of Goldstone's approach are decisive. The connected diagram theorem is derived both in a constructive way based on a Lie‐algebraic formulation and a nonconstructive way making use of the separation theorem. It is discussed why the Goldstone derivation starting from a unitary time‐evolution operator, ends up with a wave operator in intermediate normalization. The Møller–Plesset perturbation expansions of Bartlett and Pople are compared. Examples of complete summations of certain classes of diagrams are discussed, for example, that which leads to the Bethe‐Goldstone expansion. MBPT for energy differences is analyzed. The paper ends with recent developments and challenges, such as the generalization of normal ordering to arbitrary reference states, contracted Schrödinger k‐particle equations and Brillouin conditions, and finally the Nakatsuji theorem and the Nooijen conjecture. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009