New simulations to qualify eutectic lithium-lead as breeder material

Pb17Li is today a reference breeder material in diverse fusion R&D programs worldwide. One of the main issues is the problem of liquid metals breeder blanket behavior. The knowledge of eutectic properties like optimal composition, physical and thermodynamic behavior or diffusion coefficients of Tritium are extremely necessary for current designs. In particular, the knowledge of the function linking the tritium concentration dissolved in liquid materials with the tritium partial pressure at a liquid/gas interface in equilibrium, CT =f(PT ), is of basic importance because it directly impacts all functional properties of a blanket determining: tritium inventory, tritium permeation rate and tritium extraction efficiency. Nowadays, understanding the structure and behavior of this compound is a real goal in fusion engineering and materials science. Atomistic simulations of liquids can provide much information; not only supplementing experimental data, but providing new tests of theories and ideas, making specific predictions that require experimental tests, and ultimately helping to a deeper understandin

Potential vorticity of the south polar vortex of Venus

©2016. American Geophysical UnionVenus' atmosphere shows highly variable warm vortices over both of the planet's poles. The nature of the mechanism behind their formation and properties is still unknown. Potential vorticity is a conserved quantity when advective processes dominate over friction and diabatic heating and is a quantity frequently used to model balanced flows. As a step toward understanding the vortices' dynamics, we present maps of Ertel's potential vorticity (EPV) at Venus' south polar region. We analyze three configurations of the south polar vortex at the upper cloud level (P ~ 240 mbar; z ~ 58 km), based on our previous analyses of cloud motions and thermal structure from data acquired by the Visual and InfraRed Thermal Imaging Spectrometer instrument on board Venus Express. Additionally, we tentatively estimate EPV at the lower cloud level (P ~ 2200 mbar; z ~ 43 km), based on our previous wind measurements and on static stability data from Pioneer Venus and the Venus International Reference Atmosphere (VIRA) model. Values of EPV are on the order of 10−6 and 10−8 K m2 kg−1 s−1 at the upper and lower cloud levels, respectively, being 3 times larger than the estimated errors. The morphology observed in EPV maps is mainly determined by the structures of the vertical component of the relative vorticity. This is in contrast to the vortex's morphology observed in 3.8 or 5 µm images which are related to the thermal structure of the atmosphere at the cloud top. Some of the EPV maps point to a weak ringed structure in the upper cloud, while a more homogenous EPV field is found in the lower cloud

Mirror matter admixtures and isospin breaking in the \Delta I=1/2 rule in \Omega^- two body non-leptonic decays

We discuss a description of \Omega^- two body non-leptonic decays based on possible, albeit tiny, admixtures of mirror matter in ordinary hadrons. The \Delta I=1/2 rule enhancement is obtained as a result of isospin symmetry and, more importantly, the rather large observed deviations from this rule result from small isospin breaking. This analysis lends support to the possibility that the enhancement phenomenon observed in low energy weak interactions may be systematically described by mirror matter admixtures in ordinary hadrons.Comment: Changed conten

Positive Feedback in the AKT/mTOR pathway and its implications for growth signal progression in skeletal muscle cells: An analytical study

The IGF-1 mediated AKT/mTOR pathway has been recently proposed as mediator of skeletal muscle growth and a positive feedback between Akt and mTOR was suggested to induce homogenous growth signals along the whole spatial extension of such long cells. Here we develop two biologically justied approximations which we study under the presence of four dierent initial conditions that describe dierent paradigms of IGF-1 receptor{induced Akt/mTOR activation. In rst scenario the activation of the feedback cascade was assumed to be mild or protein turnover considered to be high. In turn, in the second scenario the transcriptional regulation was assumed to maintain dened levels of inactive pro{enzymes. For both scenarios, we were able to obtain closed{form formulas for growth signal progression in time and space and found that a localised initial signal maintains its Gaussian shape, but gets delocalised and exponentially degraded. Importantly, mathematical treatment of the reaction diusion system revealed that diusion ltered out high frequencies of spatially periodic initiator signals suggesting that the muscle cell is robust against uctuations in spatial receptor expression or activation. However, neither scenario was consistent with the presence of stably travelling signal waves. Our study highlights the role of feedback loops in spatiotemporal signal progression and results can be applied to studies in cell proliferation, cell dierentiation and cell death in other spatially extended cells

Pediatric Meningosarcoma: Clinical Evolution and Genetic Instability

This report presents a female diagnosed with a frontoparietal interhemispheric meningosarcoma who, parallel to the clinical worsening, revealed an increase in the genetic instability (in bleomycin cultures) and the complexity of the karyotypes, with the acquisition of a clonal deletion of 17p13 (the locus for the TP53 tumor suppressor gene). The genetic findings of this patient suggest that the increased genetic instability could contribute to tumor progression as well as to treatment resistance, possibly in the background of the clonal deletion of TP53

Nonclonal Chromosomal Aberrations Induced by Anti-Tumoral Regimens in Childhood Cancer: Relationship with Cancer-Related Genes and Fragile Sites

Cytogenetic studies were performed on 80 pediatric cancer patients to observe the chromosomal damage, both quantitative and qualitative, induced by chemotherapy. Peripheral blood lymphocytes (PBL) (n = 127) were obtained at diagnosis, during treatment, at remission, and at relapse, and chromosome analysis performed utilizing G-banding standard procedures. The results show a significant increase in the number of altered karyotypes (P = 0.03) in the samples during treatment, returning to values that were similar to those at diagnosis at 2-year remission. Most of the chromosomal aberrations (CA) detected during the chemotherapy regimens were nonclonal, unbalanced (75%), and involved chromosomes 1, 3, 5, 6, 11, 12, 16, and 17 most frequently. There was also a marked increase of CA in samples at relapse with very similar features (type and distribution) to those detected during treatment. There was a good correlation between the chromosomal breakpoints in our series and fragile sites (58%), oncogene (75%), and tumor suppressor gene (33%) loci described in the literature. The results obtained suggest that cytostatic drugs induce a transient increase in chromosome fragility occurring at several cancer-associated breakpoints

Temperature-dependence of the hyperfine interaction in the cubic phase of BaHfO₃

The temperature dependence of the hyperfine interaction in the paraelectric phase of BaHfO₃ in the temperature range from liquid-nitrogen temperature to 1350 K has been studied. The experimental results show an Abragam-Pound mechanism for the attenuation of the angular correlation. In this cubic structure the attenuation would be consistent with a relaxation mechanism that involves O-ion hopping between vacant sites in the lattice. Using the point-charge model for the estimation of the electric field gradient produced by an O vacancy in the coordination sphere of the probe ion, the process is characterized by a correlation time τ_(c) = 12 ± 1 ps at RT

Clinical and Molecular Features of Ewing Sarcoma in a Patient with Triple-X Syndrome

A case of Ewing sarcoma in a 16-year-old girl with 47 XXXc karyotype is reporte

Dynamical approach to the Casimir effect

Casimir forces can appear between intrusions placed in different media driven by several fluctuation mechanisms, either in equilibrium or out of it. Herein, we develop a general formalism to obtain such forces from the dynamical equations of the fluctuating medium, the statistical properties of the driving noise, and the boundary conditions of the intrusions (which simulate the interaction between the intrusions and the medium). As a result, an explicit formula for the Casimir force over the intrusions is derived. This formalism contains the thermal Casimir effect as a particular limit and generalizes the study of the Casimir effect to such systems through their dynamical equations, with no appeal to their Hamiltonian, if any exists. In particular, we study the Casimir force between two infinite parallel plates with Dirichlet or Neumann boundary conditions, immersed in several media with finite correlation lengths (reaction--diffusion system, liquid crystals, and two coupled fields with non-Hermitian evolution equations). The driving Gaussian noises have vanishing or finite spatial or temporal correlation lengths; in the first case, equilibrium is reobtained and finite correlations produce nonequilibrium dynamics. The results obtained show that, generally, nonequilibrium dynamics leads to Casimir forces, whereas Casimir forces are obtained in equilibrium dynamics if the stress tensor is anisotropic.Comment: 12 pages, 1 figur

Anxiety and risk of vascular dementia in an elderly community sample: The role of sex

Background: To assess the association between anxiety and risk of vascular dementia (VaD), as well as potential sex differences, in a community-based cohort. Methods: A random sample of 4057 dementia-free community participants aged 55 or older, from the longitudinal, community-based Zaragoza Dementia and Depression Project (ZARADEMP) study were followed for 4.5 years. Geriatric Mental State B (GMS)-Automated Geriatric Examination for Computer Assisted Taxonomy (AGECAT) was used for the assessment and diagnosis of anxiety, and a panel of research psychiatrists diagnosed the incident cases of VaD according to DSM-IV (Diagnostic and Statistical Manual of mental disordes). Multivariate survival analysis with competing risk regression model was performed. Results: In men, the incidence rate of VaD was significantly higher among anxiety subjects compared with non-anxiety subjects (incidence rate ratio (IRR) (95% confidence interval (CI)): 3.24 (1.13–9.35); p = 0.029), and no difference was observed in women (IRR (95%CI): 0.68 (0.19– 2.23); p = 0.168). In the multivariate model, for men, cases of anxiety had 2.6-fold higher risk of VaD (subdistribution hazard ratio (SHR): 2.61; 95%CI: 0.88–7.74) when all potential confounding factors were controlled, with no statistical significance (p = 0.084), but a clinically relevant effect (Cohen’s d: 0.74). No association was found in women. Conclusions: In men, but not in women, risk of VaD was higher among individuals with anxiety, with a clinically relevant effect. Potential anxiety-related preventive interventions for VaD might be tailored to men and women separately