Loss of strength in Ni3Al at elevated temperatures

Stress decrease above the stress peak temperature (750 K) is studied in h123i single crystals of Ni3(Al, 3 at.% Hf ). Two thermally activated deformation mechanisms are evidenced on the basis of stress relaxation and strain rate change experiments. From 500 to 1070 K, the continuity of the activation volume/temperature curves reveals a single mechanism of activation enthalpy 3.8 eV/atom and volume 90 b3 at 810K with an athermal stress of 330 MPa. Over the very same temperature interval, impurity or solute diffusion towards dislocation cores is evidenced through serrated yielding, peculiar shapes of stress–strain curves while changing the rate of straining and stress relaxation experiments. This complicates the identification of the deformation mechanism, which is likely connected with cube glide. From 1070 to 1270 K, the high-temperature mechanism has an activation enthalpy and volume of 4.8 eV/atom and 20 b3, respectively, at 1250 K

Development of fundamental motor skills between 2006 and 2016 in Dutch primary school children

Background: Fundamental Motor Skills (FMS) are important building blocks for children’s sport-participation and lifelong physical activity. In the last decade, several international studies have reported delays in the development of FMS. To get better insight into the Dutch situation and to provide future directions, this study examined the development of FMS in Dutch primary school children.Method: The main goal of this study is to compare FMS of 11–12-year-old Dutch children in 2016 with scores of similarly-aged-children in 2006. In addition, gender, age, BMI were taken into account, to see whether changes in motor performance are related to these child characteristics. FMS-test scores on seven motor competence tests (balance, swing, jump, roll, shoot, throwing and catching, and tennis) from 1939 children in 2016 were set side by side with those of 1648 children in 2006. Temporal changes in motor competence scores were analyzed using regression-analysis.Results: This cross-sectional study shows better results for the children in 2006 compared to similarly-aged-children in 2016. Lower scores were found on six out of seven tested FMS, with the largest declines on the object control skills tennis and throwing and catching. Only vaulting jump skills remained on the same level. Overall, children with a higher BMI scored lower on all tests, except for throwing and catching via the wall. On the balancing, jumping and tennis test, the gap with children with a lower BMI widened over the last decade. Girls showed a lower competence level on rolling, shooting and throwing and catchingcompared to boys. During the last decade, their performance on the tennis test decreased more than for boys. Conclusions: Results of this study are alarming as diminishing motor skills are related to lower sport participation and poorer health outcomes. For the future generation, new interventions are needed to help children reach a sufficient proficiency level in FMS, to prevent or overcome the negative effects of lowered motor skills. Targeting FMS components during physical education and outside of school hours may potentially be a valuable strategy in reverting the lowering FMS levels amongst childre

Spectral modification of laser-accelerated proton beams by self-generated magnetic fields

Target normal measurements of proton energy spectra from ultrathin (50-200 nm) planar foil targets irradiated by 10(19) W cm(-2) 40 fs laser pulses exhibit broad maxima that are not present in the energy spectra from micron thickness targets (6 mu m). The proton flux in the peak is considerably greater than the proton flux observed in the same energy range in thicker targets. Numerical modelling of the experiment indicates that this spectral modification in thin targets is caused by magnetic fields that grow at the rear of the target during the laser-target interaction

Measurement of the viscoelastic properties of blood plasma clot formation in response to tissue factor concentration-dependent activation

© 2016, The Author(s). The coagulation of blood plasma in response to activation with a range of tissue factor (TF) concentrations was studied with a quartz crystal microbalance (QCM), where frequency and half width at half maximum (bandwidth) values measured from the conductance spectrum near resonant frequency were used. Continuous measurement of bandwidth along with the frequency allows for an understanding of the dissipative nature of the forming viscoelastic clot, thus providing information on the complex kinetics of the viscoelastic changes occurring during the clot formation process. Using a mathematical model, these changes in frequency and bandwidth have been used to derive novel QCM parameters of effective elasticity, effective mass density and rigidity factor of the viscoelastic layer. The responses of QCM were compared with those from thromboelastography (TEG) under identical conditions. It was demonstrated that the nature of the clot formed, as determined from the QCM parameters, was highly dependent on the rate of clot formation resulting from the TF concentration used for activation. These parameters could also be related to physical clot characteristics such as fibrin fibre diameter and fibre density, as determined by scanning electron microscopic image analysis. The maximum amplitude (MA) as measured by TEG, which purports to relate to clot strength, was unable to detect these differences

Numerical Evaluation of P-Multigrid Method for the Solution of Discontinuous Galerkin Discretizations of Diffusive Equations

This paper describes numerical experiments with P-multigrid to corroborate analysis, validate the present implementation, and to examine issues that arise in the implementations of the various combinations of relaxation schemes, discretizations and P-multigrid methods. The two approaches to implement P-multigrid presented here are equivalent for most high-order discretization methods such as spectral element, SUPG, and discontinuous Galerkin applied to advection; however it is discovered that the approach that mimics the common geometric multigrid implementation is less robust, and frequently unstable when applied to discontinuous Galerkin discretizations of di usion. Gauss-Seidel relaxation converges 40% faster than block Jacobi, as predicted by analysis; however, the implementation of Gauss-Seidel is considerably more expensive that one would expect because gradients in most neighboring elements must be updated. A compromise quasi Gauss-Seidel relaxation method that evaluates the gradient in each element twice per iteration converges at rates similar to those predicted for true Gauss-Seidel

New Synthetic Thrombin Inhibitors: Molecular Design and Experimental Verification

BACKGROUND: The development of new anticoagulants is an important goal for the improvement of thromboses treatments. OBJECTIVES: The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. METHODS: Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies) were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. RESULTS: New compounds that are both effective direct thrombin inhibitors (the best K(I) was <1 nM) and strong anticoagulants in plasma (an IC(50) in the thrombin generation assay of approximately 100 nM) were discovered. These compounds contain one of the following new residues as the basic fragment: isothiuronium, 4-aminopyridinium, or 2-aminothiazolinium. LD(50) values for the best new inhibitors ranged from 166.7 to >1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions) were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. CONCLUSIONS: The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications

Biologics Delay Progression of Crohn's Disease, but Not Early Surgery, in Children

Background & Aims: Up to 30% of patients with Crohn's disease (CD) require surgery within the first 5 years from diagnosis. We investigated the recent risk of bowel surgery in an inception cohort of pediatric patients with CD and whether early use of biologics (tumor necrosis factor antagonists) alters later disease course. Methods: We collected data from the Pediatric Inflammatory Bowel Disease Collaborative Research Group registry on 1442 children (age, ó16 y) diagnosed with CD from January 2002 through December 2014. Data were collected at diagnosis, 30 days following diagnosis, and then quarterly and during hospitalizations for up to 12 years. Our primary aim was to determine the 10-year risk for surgery in children with CD. Our secondary aim was to determine whether early use of biologics (<3 mo of diagnosis) affected risk of disease progression. Results: The 10-year risk of first bowel surgery was 26%. The 5-year risk of bowel surgery did not change from 2002 through 2014, and remained between 13% and 14%. Most surgeries occurred within 3 years from diagnosis. The only predictor of surgery was disease behavior at diagnosis. CD with inflammatory behavior had the lowest risk of surgery compared to stricturing disease, penetrating disease, or both. We associated slowing of disease progression to stricturing or penetrating disease (but not surgery) with early use of biologics, but this effect only became evident after 5 years of disease. Our results indicate that biologics slow disease progression over time (hazard ratio, 0.85; 95% CI, 0.76?0.95). Conclusions: In an analysis of data from a registry of pediatric patients with CD, we found that among those with significant and progressing disease at or shortly after presentation, early surgery is difficult to prevent, even with early use of biologics. Early use of biologics (<3 mo of diagnosis) can delay later disease progression to stricturing and/or penetrating disease, but this affect could become evident only years after initial management decisions are made

Genetic Diversity of Staphylocoagulase Genes (coa): Insight into the Evolution of Variable Chromosomal Virulence Factors in Staphylococcus aureus

. Although SCs have been classified into 10 serotypes based on the differences in the antigenicity, genetic bases for their diversities and relatedness to chromosome types are poorly understood. type except for the cases of CC1 and CC8, which contained two and three different SC types, respectively. loci, resulting in the carriage of the combinations of allotypically different important virulence determinants in staphylococcal chromosome