bluuebunny/crossref_metadata_2025_split huggingface dataset:
Precipitation of Co from supersaturated Au90Co10: microstructure and kinetics
Authors: Bauer Rico , Bischoff Ewald , Mittemeijer Eric Jan 
Published: September 2011

AbstractThe kinetics of the precipitation of Co from a supersaturated solid solution of Au-10.12 at.% Co was investigated by differential scanning calorimetry upon isothermal annealing at temperatures in the range from 567 K to 612 K and upon isochronal annealing at heating rates between 5 K min−1and 40 K min−1. The microstructural evolution during the course of precipitation was traced by (high-resolution) transmission electron microscopy, scanning electron microscopy, X-ray diffraction and hardness measurements. First, the exothermic formation of 0.5 – 1 nm thin plate-like bcc Co precipitates takes place parallel to {100} habit planes of the Au-matrix. Upon continued annealing, equiaxed fcc Co particles in epitaxial orientation with the Au lattice occur by a Bain-type transformation of the Co particles from the bcc to the fcc lattice structure associated with loss of coherency. Fitting of a modular model of transformation kinetics (Liu et al., Int. Mat. Rev. 52 (2007) 193) simultaneously to the first peak of all isothermal differential scanning calorimetry runs and simultaneously to the first peak of all isochronal differential scanning calorimetry runs demonstrated that the nucleation of bcc Co plates is governed by site saturation in the case of isothermal annealing and continuous nucleation in the case of isochronal annealing, and by linear growth for both isothermal and isochronal annealing. The activation energy for growth is remarkably small due to the presence of quenched-in vacancies. Recovery prior to precipitation leads to a change of the nucleation mechanism from site saturation to continuous nucleation as well as an increase in the activation energy for growth.
The effect of heat treatments on the microstructure, texture and mechanical properties of the extruded magnesium alloy ME21
Authors: Brömmelhoff Katrin , Huppmann Michael , Reimers Walter 
Published: September 2011

Abstract
Heat treatments of the hot extruded magnesium alloy ME21 were performed at 400 °C – 550 °C and various annealing times. The evolution of the microstructure, the texture and the resulting mechanical properties were investigated. The heat treatments result in grain growth and in an intensification of the so-called rare earth texture. The grain coarsening results in a decrease in the yield strength according to the Hall – Petch relationship. The rare earth texture also contributes to a decrease in the yield strength due to the easy activation of basal slip systems. However, this texture improves the ductility at room temperature. The combination of large grain sizes, dissolved Mg12Ce precipitates and the rare earth texture delivers fracture strains up to  – 55 % under compression. The elongation under tension is less affected.
Beyond Ni-based superalloys: Development of CoRe-based alloys for gas turbine applications at very high temperatures
Authors: Mukherji Debashis , Rösler Joachim , Strunz Pavel , Gilles Ralph , Schumacher Gerhard , Piegert Sebastian 
Published: September 2011

Abstract
High temperature material development is mainly driven by gas turbine needs. Today, Ni-based superalloys are the dominant material class in the hot section of turbines. Material development will continue to push the maximum service temperature of Ni-superalloys upwards. However, this approach has a fundamental limit and cannot be sustained indefinitely, as the Ni-superalloys are already used very close to their melting point. Within the framework of a DFG Forschergruppe program (FOR 727) – “Beyond Ni-base Superalloys” – CoRe based alloys are being developed at the Technische Universität Braunschweig as a new generation of high temperature materials that can be used at + 100 °C above single crystal Ni-superalloys. Two main strengthening concepts, namely precipitation hardening by MC carbides and composite hardening by Co2Re3-type σ phase are being explored in CoRe alloy development. Selected results of microstructural characterizations, including in-situ measurements by synchrotron and neutron scattering are presented.
Accumulation of radiation damage and disordering in MgAl2O4 under swift heavy ion irradiation
Authors: Yasuda Kazuhiro , Yamamoto Tomokazu , Etoh Motoki , Kawasoe Shinji , Matsumura Syo , Ishikawa Norito 
Published: September 2011

Abstract
Accumulation and recovery of radiation-induced damage with swift heavy ions in stoichiometric magnesium aluminate spinel, MgAl2O4, has been investigated. Microstructural change and atomic disordering was examined through transmission electron microscopy (TEM) techniques, with bright-field (BF) and high-resolution (HR) TEM images, and high angular resolution electron channelling X-ray spectroscopy (HARECXS), for single crystal MgAl2O4 irradiated with 200 MeV Xe, and 340 or 350 MeV Au ions. The density of core damage region, detected by BFTEM with Fresnel-contrast, increased proportionally with ion fluence at the early stage of accumulation and saturated at a fluence higher than 1016 ions m2. This result is discussed with a balance between the formation and recovery of the core damage region under irradiation, and the influence region to induce the recovery was evaluated to be 7 – 9 nm in radius. HARECXS and electron diffraction analysis revealed that cations at tetrahedral sites preferentially occupy octahedral sites to transform to defective rock-salt structure. The structure of the core damage region is found from HR and BFTEM images to be a columnar vacancy-rich region with a low atomic density.
The origin and development of the P{011}<111> orientation during recrystallization of particle-containing alloys
Authors: Schäfer Carmen , Gottstein Günter 
Published: September 2011

Abstract
During annealing of particle-containing aluminum alloys, very often the development of the so-called P {011}<111>-texture and ND-rotated Cube {001}<310>-texture components are observed. The present paper focuses on the origin of the P-component near particles in an Al-1.1 wt.% Mn alloy and its further evolution during annealing. It is shown that the occurrence of these components depends on the annealing treatment rather than on the absolute annealing temperature.
Dislocationless sliding in a polycluster glass
Authors: Lazarev Nikolai , Bakai Alexander 
Published: September 2011

Abstract
At low temperature, T → 0, the yield stress of a perfect crystal is equal to its so called theoretical strength. The yield stress of imperfect crystals is controlled by the stress threshold of dislocation mobility. A non-crystalline solid has neither the ideal structure nor gliding dislocations. Its yield stress depends on the distribution of local critical stresses attributed to each atomic site at which the local inelastic deformation occurs. We describe the exactly solvable model of planar layer strength and sliding with an arbitrary homogeneous distribution of local critical stresses. The kinetics of thermally-activated creep of the sliding layer is described. The sliding activation volume scales with the applied external stress as ∼ωe
-β, where β < 1.
The proposed model accounts for mechanisms of the low temperature deformation of polycluster metallic glasses, since intercluster boundaries of a polycluster metallic glass are natural sliding layers of the described type. We also discuss applicability of the model to the low temperature plastic deformation of nano-crystalline materials.
Evaluation of Vacuum Venting for Micro-injection Molding
Authors: Yoon S.-H. , Padmanabha P. , Cha N.-G. , Mead J. L. , Barry C. M. F. 
Published: September 2011

Abstract
While the effect of vacuum venting has been reported for injection molding of micro and nanoscale features, the limited research has produced conflicting results. To clarify the positive effect of vacuum venting on replication of microscale features, this work focused on the interactions between vacuum venting and (1) feature size, (2) material type in terms of melt viscosity and wettability, and (3) injection velocity and mold temperature. A metal-polymer hybrid tooling with a range of positive microscale features was employed to mold polystyrene and polymethylmethacrylate parts. Overall, vacuum venting always effective in feature definition (sharpness of edges) enhancement, but provided increases in depth ratio that depended on material (melt viscosity and wettability) and processing conditions (i.e., injection velocity, and mold temperature).
Preparation of Poly(acrylic acid)-Poly(ethylene oxide) Nanofibers via Electrospinning and Investigation of Their Morphology
Authors: Shami Z. , Sharifi-Sanjani N. 
Published: September 2011

Abstract
The poly(acrylic acid)/poly(ethylene oxide) (PAA/PEO) blend nanofibers at 100/0, 80/20, 50/50, 20/80 and 0/100 weight ratios were obtained via electrospinning process. Intermolecular interactions, miscibility and compatibility of polymer blends were studied by Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and UV-visible spectrophotometer. The results suggest that intermolecular interactions have occurred between pure PAA and PEO in PAA/PEO blend. These interactions made PAA/PEO blend miscible at above-mentioned weight ratios. Additionally, the morphology and the fibers diameter were investigated using scanning electron microscope (SEM) analysis, which indicated beadless fibers with diameter range of about 120 to 300 nm. It was observed that the homogenous nanofibers with the smaller diameter were obtained in PAA/PEO blend with PAA dominant content. Finally, SEM results suggest that the formation of pure PAA nanofibers with concentration of 5.0 wt.% would not occur. Whereas, in the same concentration, pure PEO and PAA/PEO blend nanofibers with no bead defects were obtained. However, in higher pure PAA concentrations electrospun fibers were formed.
Influence of Processing Conditions on Productivity, Thermal and Rheological Properties of Reprocessed Low Density Polyethylene
Authors: Pistor V. , Chiesa A. , Ornaghi H. L. , Fiorio R. , Zattera A. J. 
Published: September 2011

Abstract
The market for recycled thermoplastic polymers is undergoing a sharp increase, although recyclate polymers are regarded as materials with inferior properties when compared to the virgin material. This study investigates the behavior of non-contaminated scraps of low density polyethylene (LDPE) from the plastic packaging industry after single processing stage, in terms of the productivity and the thermal and rheological properties. The LDPE used was reprocessed on a single-screw extruder (Miotto) of 90 mm screw diameter and L/D = 25. Three screw speeds (80, 90 and 100 min−1) were investigated at three processing temperatures (200, 250 and 300°C). The reprocessed materials were characterized by thermogravimetric analysis TGA, parallel plates rheometry and productivity. The results obtained by TGA showed a typical range of polyolefin degradation (350 to 450°C). The viscoelastic properties did not show significant changes in relation to the rheological behavior. Increasing the temperature and screw speed promoted a productivity gain of approximately 30%. This suggests that under the conditions studied it is possible to reprocess this material with good productivity ensuring its thermal, mechanical and rheological properties.
Using Supercritical Carbon Dioxide for Physical Foaming of Advanced Polymer Materials
Authors: Wolff F. , Zirkel L. , Betzold S. , Jakob M. , Maier V. , Nachtrab F. , Nicolat B. Ceron , Fey T. , Münstedt H. 
Published: September 2011

AbstractFoams from high performance polymers find more and more interest. The processes to generate them can be difficult, however. It is shown how physical foaming with CO2can be used as a first step to assess the potentials of such materials. For investigations of such kind an autoclave on a laboratory scale which allows pressure variations up to 300 bars and temperatures up to 300°C was set up. The samples are saturated with supercritical carbon dioxide (s.c. CO2) which acts as a foaming agent. Depending on the process and material parameters different foam characteristics and cell morphologies were obtained and characterised. The potential of this method is demonstrated for two different classes of advanced polymer materials, thermoplastic fluoropolymers (FEP), and a silicone resin. In the case of the fluoropolymer, previously prepared films were foamed and the effects of various process parameters on the foam characteristics were investigated. Besides the general potential of foams from fluoropolymers, they are candidates for polymeric piezoelectric materials with a relatively high temperature stability. Silicone polymers possess some properties superior to common organic polymers. First results on the foaming behaviour of a silicone resin are presented.
Exploring Pharmacists' Understanding and Adoption of Prescribing in 2 Canadian Jurisdictions: Design and Rationale for a Mixed-Methods Approach
Authors: Guirguis Lisa , Cooney Dale , Dolovich Lisa , Eberhart Greg , Hughes Christine , Makowsky Mark , Sadowski Cheryl , Schindel Theresa , Yuksel Nesé 
Published: September 2011

Background: Although pharmacists have been granted prescribing privileges in Alberta since 2007 and most other Canadian provinces have granted or put forward similar legislation since then, there is a lack of Canadian data exploring pharmacists' understanding and adoption of prescribing practice. Therefore, our goal is to investigate pharmacists' perceptions of prescribing, the extent to which prescribing has been incorporated into pharmacists' practices and the factors that have influenced its uptake. Methods (Study Design): We are conducting a mixed-methods evaluation of pharmacist prescribing in Alberta and Ontario consisting of 3 consecutive stages: 1) semi-structured interviews with a small cohort of pharmacists in Alberta and Ontario; 2) development of a survey guided by responses identified in Stage 1; and 3) a mixed-methods survey of a large random sample of pharmacists in Alberta. Conclusion: When complete, this study will inform researchers, policy-makers and educators about Ontario pharmacists' attitudes towards prescribing and the initial uptake of prescribing practice in Alberta. This will allow for a greater understanding of pharmacists' perceptions of prescribing; the extent to which prescribing has been incorporated into pharmacy practice; and the factors facilitating its uptake.
Il28B Cc-Genotype Association with Hla-Dqb1*0301 Allele Increases the Prediction of Spontaneous HCV RNA Clearance in Thalassaemic HCV-Infected Patients
Authors: Mangia Alessandra , Santoro Rosanna , Sarli Roberto , Mottola Leonardo , Piazzolla Valeria , Petruzzellis Daniela , Bacca Donato , Clemente Rocco , Copetti Massimiliano , di Mauro Lazzaro , Lotti Giuseppe , Sacco Michele , Stefano Ippazio 
Published: September 2011

Background A single nucleotide polymorphism (SNP), upstream of the IL28B gene has been recently associated with natural clearance of HCV. In a well-characterized cohort of patients with thalassaemia major exposed to the risk of acquiring HCV infection by blood transfusions, we aimed to replicate this finding and to evaluate whether combining the IL28B genotype and HLA class II alleles allow viral clearance to be accurately predicted. Methods Of 168 patients, 130 with complete clinical history were included in the analysis. According with their HCV antibodies status 13 were defined HCV resistant, and 117 infected. Infected patients were subdivided, giving 49 with self-limiting and 68 with ongoing infection. Results IL28B CC-genotype was observed in 32 patients with self-limiting and in 23 with ongoing infection (64% versus 34%; P=0.004). HLA DQB1*0301 allele was associated with viral clearance in 36 cases (73%; P<0.0001). Both DQB1*0301 and IL28B CC-genotype were found to be independent predictors of HCV clearance (OR=5.64, 95% CI 1.52–20.9 and OR=5.76, 95% CI 2.16–15.33, respectively). With the addition of DQB1*0301, the accuracy of the prediction increased from 63% to 69%. Conclusions In addition to IL28B CC-genotype, HLA DQB1*0301 helps in predicting natural clearance of HCV after acute infection.
Pharmacokinetics of Antiretroviral Drugs in Anatomical Sanctuary Sites: The Male and Female Genital Tract
Authors: Else Laura J , Taylor Stephen , Back David J , Khoo Saye H 
Published: September 2011

HIV resides within anatomical ‘sanctuary sites’, where local drug exposure and viral dynamics may differ significantly from the systemic compartment. Suboptimal anti-retroviral concentrations in the genital tract may result in compartmentalized viral replication, selection of resistant mutations and possible re-entry of wild-type/resistant virus into the systemic circulation. Therefore, achieving adequate antiretroviral exposure in the genital tract has implications for the prevention of sexual and vertical transmission of HIV. Penetration of antiretrovirals in the genital tract is expressed by accumulation ratios derived from the measurement of drug concentrations in time-matched seminal plasma/cervicovaginal fluid and plasma samples. Penetration varies by gender and may be drug (as opposed to class) specific with high interindividual variability. Concentrations in seminal plasma are highest for nucleoside analogues and lowest for protease inhibitors and efavirenz. Seminal accumulation of newer agents, raltegravir and maraviroc, is moderate (rank order of accumulation is nucleoside/nucleotide reverse transcriptase inhibitors [lamivudine/zidovudine/tenofovir/didanosine > stavudine/abacavir] > raltegravir > indinavir/maraviroc/nevirapine >> efavirenz/protease inhibitors [amprenavir/atazanavir/darunavir > lopinavir/ritonavir > saquinavir] > enfuvirtide). In the female genital tract, the nucleoside analogues exhibit high accumulation ratios, whereas protease inhibitors have limited penetration; however, substantial variability exists between individuals and study centres. Second generation non-nucleoside reverse transcriptase inhibitor etravirine, and maraviroc and raltegravir, demonstrate effective accumulation in cervicovaginal secretions (rank order of accumulation is nucleoside/nucleotide reverse transcriptase inhibitor [zidovudine/lamivudine/didanosine > emtricitabine/tenofovir] > indinavir > maraviroc/raltegravir/darunavir/etravirine > nevirapine/abacavir > protease inhibitors [amprenavir/atazanavir/ritonavir] > lopinavir/stavudine/efavirenz > saquinavir).
IL-13 Receptor α1 Differentially Regulates Aeroallergen-Induced Lung Responses
Authors: Rothenberg Marc E. , Wen Ting , Shik Dana , Cole Eric T. , Mingler Melissa M. , Munitz Ariel 
Published: September 2011

Abstract
IL-13 and IL-4 are hallmark cytokines of Th2-associated diseases including asthma. Recent studies revealed that IL-13Rα1 regulates asthma pathogenesis by mediating both IL-4– and IL-13–mediated responses. Nonetheless, the relative contribution of each cytokine in response to aeroallergen challenge and the degree of functional dichotomy between IL-4 and IL-13 in asthma remains unclear. Consistent with prior publications, we demonstrate that IL-13Rα1 regulates aeroallergen-induced airway resistance and mucus production but not IgE and Th2 cytokine production. We demonstrate that aeroallergen-induced eosinophil recruitment and chemokine production were largely dependent on IL-13Rα1 after Aspergillus but not house dust mite (HDM) challenges. Notably, Aspergillus-challenged mice displayed increased IL-13Rα1–dependent accumulation of dendritic cell subsets into lung-draining lymph nodes in comparison with HDM-challenged mice. Comparison of IL-4 and IL-13 levels in the different experimental models revealed increased IL-4/IL-13 ratios after HDM challenge, likely explaining the IL-13Rα1–independent eosinophilia and chemokine production. Consistently, eosinophil adoptive transfer experiments revealed near ablation of lung eosinophilia in response to Aspergillus in Il13ra1−/− mice, suggesting that Aspergillus-induced lung eosinophil recruitment is regulated by IL-13–induced chemokine production rather than altered IL-13 signaling in eosinophils. Furthermore, the near complete protection observed in Il13ra1−/− mice in response to Aspergillus challenge was dependent on mucosal sensitization, as alum/Aspergillus-sensitized mice that were rechallenged with Aspergillus developed IL-13Rα1–independent eosinophilia although other asthma parameters remained IL-13Rα1 dependent. These results establish that IL-13Rα1 is required for aeroallergen-induced airway resistance and that allergen-induced chemokine production and consequent eosinophilia is dictated by the balance between IL-4 and IL-13 production in situ.
Balloon Angioplasty for Disruption of Tunneled Dialysis Catheter Fibrin Sheath
Authors: Watorek Ewa , Gołebiowski Tomasz , Letachowicz Krzysztof , Garcarek Jerzy , Kurcz Jacek , Bartosik Hanna Augustyniak , Letachowicz Waldemar , Weyde Wacław , Klinger Marian 
Published: September 2011

Purpose Management of failing tunneled hemodialysis catheters, sometimes the only vascular access for hemodialysis, presents a difficult problem. In spite of various techniques having been developed, no consensus has been reached about the preferred technique, associated with the longest catheter patency. Methods We report disruption of the fibrin sheath covering dysfunctional tunneled hemodialysis catheter by means of angioplasty, followed by over guidewire catheter exchange. Results Following the procedure, the catheter placed in the recovered lumen of the vessel presented correct function. Conclusions The described procedure allowed maintenance of vascular access in our patient. Additionally, dilatation of the concomitant central vein stenosis opens an option for another attempt for arteriovenous fistula creation.
Novel Cyclization Reactions of Aminoallenes
Authors: Alcaide Benito , Almendros Pedro 
Published: September 2011

AbstractThe aminoallene moiety represents an excellent building block for heterocyclization reactions, affording a large number of cyclic structures containing different sized skeletons in a single step. This strategy has been studied under basic and electrophile‐induced conditions. More recently, the use of transition metal catalysis has been introduced as an alternative relying on the activation of the allenic component. This overview focuses on the most recently developed cyclizations of aminoallenes along with remarkable early works accounting for the mechanism, as well as for the regio‐ and stereoselectivity of the cyclizations.