Mineral–water reactions in Earth’s mantle:Predictions from Born theory and ab initio molecular dynamics

Recent studies present compelling evidence that a free aqueous fluid phase exists within the upper mantle. Fluid may be present at depths as great as the transition zone (410–660 km) and possibly beyond. The chemical reactivity of such deep fluids can be predicted from the Born model of solvation. To use the Born model, we need to know the dielectric constant of water under mantle conditions. We have used ab initio molecular dynamics simulations to determine the dielectric constant of water up to a pressure of 30 GPa and a temperature of 3000 K. Increased temperature lowers the dielectric constant and decreases ion solvation, but pressure overcomes this effect. The resulting high dielectric constant suggests that aqueous mantle fluids are highly reactive for ion solvation and mineral dissolution. We tested this by using the Helgeson–Kirkham–Flowers equation of state to estimate free energies of several mineral-solution and ion solvation reactions under mantle conditions. The results support previous estimates of carbonate solubility in the mantle. We also find that mantle fluids may play a key role in transporting ore metals: we evaluated the solubility of chalcopyrite and the complexation of Cu and Fe by Cl under mantle conditions and find that metal complexation is as significant as in ore-forming fluids in the crust. At reasonable conditions of pH and fH2, chalcopyrite is highly soluble. We tentatively hypothesize that exsolved fluids from subducted slabs may extract and mobilize primary sulfides in the mantle, implying potentially deep sources for porphyry copper deposits

Optical properties of tungsten thin films perforated with a bidimensional array of subwavelength holes

We present a theorical investigation of the optical transmission of a dielectric grating carved in a tungsten layer. For appropriate wavelengths tungsten shows indeed a dielectric behaviour. Our numerical simulations leads to theoretical results similar to those found with metallic systems studied in earlier works. The interpretation of our results rests on the idea that the transmission is correlated with the resonant response of eigenmodes coupled to evanescent diffraction orders.Comment: 4 pages, 3 figure

Optical properties of MgH2 measured in situ in a novel gas cell for ellipsometry/spectrophotometry

The dielectric properties of alpha-MgH2 are investigated in the photon energy range between 1 and 6.5 eV. For this purpose, a novel sample configuration and experimental setup are developed that allow both optical transmission and ellipsometric measurements of a transparent thin film in equilibrium with hydrogen. We show that alpha-MgH2 is a transparent, colour neutral insulator with a band gap of 5.6 +/- 0.1 eV. It has an intrinsic transparency of about 80% over the whole visible spectrum. The dielectric function found in this work confirms very recent band structure calculations using the GW approximation by Alford and Chou [J.A. Alford and M.Y. Chou (unpublished)]. As Pd is used as a cap layer we report also the optical properties of PdHx thin films.Comment: REVTeX4, 15 pages, 12 figures, 5 table

Controle associado de Alphitobius diaperinuse efeito de microrganismos eficazes no desenvolvimento de Beauveria bassiana

O objetivo deste trabalho foi avaliar a eficiência de Beauveria bassiana (Bb), terra diatomácea (TD) e microrganismos eficazes (EM-4), associados ou não, no controle de Alphitobius diaperinus, e o efeito de EM-4 no desenvolvimento de B. bassiana. Os agentes de controle (Bb, TD e EM-4), em diferentes concentrações e combinações, foram aplicados em uma mistura de cama-de-frango e ração, em que os insetos foram acondicionados por dez dias. Avaliaram-se, in vitro: a germinação, as unidades formadoras de colônia (UFC), o crescimento vegetativo e a produtividade de conídios de Bb em contato com suspensão aquosa de EM-4 (1%) não filtrada e filtrada. Os maiores índices de mortalidade foram observados nos tratamentos TD + Bb + EM-4 e TD + Bb, nas maiores concentrações. Verificou-se efeito não-aditivo sinérgico para TD + Bb nas três concentrações. Nos testes com EM-4 filtrado, não houve diferença em relação à testemunha quanto à germinação e às UFC, entretanto, o crescimento vegetativo e a produtividade de conídios foram negativamente afetados. O uso conjunto de B. bassiana e terra diatomácea, para o manejo de populações de A. diaperinus, pode reduzir o uso de produtos químicos

The impact of the metabotropic glutamate receptor and other gene family interaction networks on autism

Although multiple reports show that defective genetic networks underlie the aetiology of autism, few have translated into pharmacotherapeutic opportunities. Since drugs compete with endogenous small molecules for protein binding, many successful drugs target large gene families with multiple drug binding sites. Here we search for defective gene family interaction networks (GFINs) in 6,742 patients with the ASDs relative to 12,544 neurologically normal controls, to find potentially druggable genetic targets. We find significant enrichment of structural defects (P≤2.40E-09, 1.8-fold enrichment) in the metabotropic glutamate receptor (GRM) GFIN, previously observed to impact attention deficit hyperactivity disorder (ADHD) and schizophrenia. Also, the MXD-MYC-MAX network of genes, previously implicated in cancer, is significantly enriched (P≤3.83E-23, 2.5-fold enrichment), as is the calmodulin 1 (CALM1) gene interaction network (P≤4.16E-04, 14.4-fold enrichment), which regulates voltage-independent calcium-activated action potentials at the neuronal synapse. We find that multiple defective gene family interactions underlie autism, presenting new translational opportunities to explore for therapeutic interventions

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

Minimum Information about T Regulatory Cells: A Step toward Reproducibility and Standardization

Nephrolog

The SARAO MeerKAT 1.3 GHz Galactic Plane Survey

We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251○ ≤l ≤ 358○ and 2○ ≤l ≤ 61○ at |b| ≤ 1 5). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8″ and a broadband RMS sensitivity of ∼10–20 μJy beam−1. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908–1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE H II region candidates are not true H II regions; and a large sample of previously undiscovered background H I galaxies in the Zone of Avoidance