The kinetics of the structural relaxation process in PHEMA-silica nanocomposites based on an equation for the configurational entropy

The enthalpy relaxation of polymer-silica nanocomposites prepared by simultaneous polymerization of poly(2-hydroxyethyl methacrylate) (PHEMA) and tetraethyloxysilane, TEOS, a silica precursor, is investigated. Both the glass transition temperature, T_g, and the temperature interval of the glass transition, ΔT _g , increase as the silica content in the sample does. Structural relaxation experiments show that the temperature interval in which conformational motions take place broadens as the silica content in the hybrid increases. A phenomenological model based on the evolution of the configurational entropy during the structural relaxation process, the SC model, has been used for determining the temperature dependence of the relaxation times during the process. The results show an increase of the fragility of the polymer as the silica content increases, a feature that can be related to the broadening of the distribution of relaxation times characterized by the β parameter of the stretched exponential distribution. On another hand the silica content increase produces a significant change of the relaxation times in the glassy state

Brain structural and functional substrates of ADGRL3 (latrophilin 3) haplotype in attention-deficit/hyperactivity disorder

Previous studies have shown that the gene encoding the adhesion G protein-coupled receptor L3 (ADGRL3; formerly latrophilin 3, LPHN3) is associated with Attention-Deficit/Hyperactivity Disorder (ADHD). Conversely, no studies have investigated the anatomical or functional brain substrates of ADGRL3 risk variants. We examined here whether individuals with different ADGRL3 haplotypes, including both patients with ADHD and healthy controls, showed differences in brain anatomy and function. We recruited and genotyped adult patients with combined type ADHD and healthy controls to achieve a sample balanced for age, sex, premorbid IQ, and three ADGRL3 haplotype groups (risk, protective, and others). The final sample (n = 128) underwent structural and functional brain imaging (voxel-based morphometry and n-back working memory fMRI). We analyzed the brain structural and functional effects of ADHD, haplotypes, and their interaction, covarying for age, sex, and medication. Individuals (patients or controls) with the protective haplotype showed strong, widespread hypo-activation in the frontal cortex extending to inferior temporal and fusiform gyri. Individuals (patients or controls) with the risk haplotype also showed hypo-activation, more focused in the right temporal cortex. Patients showed parietal hyper-activation. Disorder-haplotype interactions, as well as structural findings, were not statistically significant. To sum up, both protective and risk ADGRL3 haplotypes are associated with substantial brain hypo-activation during working memory tasks, stressing this gene's relevance in cognitive brain function. Conversely, we did not find brain effects of the interactions between adult ADHD and ADGRL3 haplotypes

SDSS-IV MaNGA: pyPipe3D analysis release for 10,000 galaxies

We present here the analysis performed using the pyPipe3D pipeline for the final MaNGA dataset included in the SDSS seventeenth data-release. This dataset comprises more than 10,000 individual datacubes, being the integral field spectroscopy galaxy survey with the largest number of galaxies. pyPipe3D processes the IFS datacubes to extract spatially-resolved spectroscopic properties of both the stellar population and the ionized-gas emission lines. A brief summary of the properties of the sample and the characteristics of the analyzed data are included. The article provides details on (i) the performed analysis, (ii) a description of the pipeline, (iii) the adopted stellar population library, (iv) the morphological and photometric analysis, (v) the adopted datamodel for the derived spatially resolved properties and (vi) the individual integrated and characteristic galaxy properties included in a final catalog. Comparisons with results from a previous version of the pipeline for earlier data releases and from other tools using this dataset are included. A practical example on how to use of the full dataset, and final catalog illustrates how to handle the delivered product. Our full analysis can be accessed and downloaded from the webpage http://ifs.astroscu.unam.mx/MaNGA/Pipe3D_v3_1_1/.Comment: 66 pages, 29 figures, 18 Tables, submitted to ApJ

Ethylene Responses and ACC oxidase Gene Expression in Lippia alba (Verbenaceae) Chemotypes with Varying Ploidy Levels

Lippia alba (Mill.) N. E. Br ex Britton & P. Wilson is a species of great economic importance due to the medicinal activity conferred by its essential oils. Ethylene (ET) is a gaseous hormone that affects several processes in plant growth and development. This hormone is synthesized through a reaction in which 1-aminocyclopropane-1-carboxylic acid (ACC) is converted to ET by the action of the enzyme ACC oxidase (ACO). The ET activity in three L. alba chemotypes (BGEN-01, triploid; BGEN-02, diploid; and BGEN-42, hexaploid) was evaluated by culturing plants in vitro in the presence of the ET precursor (ACC), scavenger mercury perchloride (MP), the inhibitors aminoethoxyvinylglycine (AVG) and silver thiosulfate (STS), and a CO2-enriched atmosphere. Leaf abscission rate, ET accumulation, and ACO gene expression (LaACO) were investigated. Leaf abscission was higher in BGEN-42, regardless of the precursor/inhibitor. ACC had the highest ET accumulation in BGEN-02 and BGEN-01, whereas BGEN-42 presented lower ET accumulation than the control. MP and AVG were effective in preventing ET production when compared to the control. LaACO was upregulated in BGEN-01 and BGEN-42 treated with ACC and in BGEN-01 treated with STS. In the CO2 enrichment experiments, LaACO expression was higher in BGEN-42 in the treatments without forced ventilation. Thus, the expression of this gene in L. alba can be altered by elevating CO2 levels and also by the addition of ACC. This is the first report of ET interactions in L. alba cultured in vitro