Characterization of quaternary ammonium compounds in Flourensia xerophytic communities and response to UV-B radiation

As part of ongoing studies aimed at characterizing molecular components involved in the ecophysiological adaptations of native xerophytic plants from central Argentina, we demonstrated the presence of compatible solutes in Flourensia campestris (FC) and Flourensia oolepis (FO), specifically glycine betaine (GB) through TLC, LC, 1H NMR and 13C-NMR. GB content (leaves: 38±7μmolg-1 DW; adult plants>seedlings), and distribution (capitula>vegetative leaves>reproductive leaves>shoots>roots) were similar to other quaternary ammonium compound (QAC) accumulators. Flourensia seedlings from both species protected from UV-B exposure - a major abiotic stress in these natural environments - showed a significant increase of GB in the leaves (p<0.01) and a significant decrease in the roots (p<0.05). In FC and FO xerophytic shrub-dominated communities QACs were detected for the first time in 41% of co-occurring species (N=39), 14 of 28 natives (50%) and 2 of 11 exotics (18%), being GB in natives only (57% of QAC accumulators). GB may be considered as a chemotaxonomical character for the genus Flourensia, since it was also detected in Flourensia hirta, Flourensia niederleinii, Flourensia riparia, Flourensia fiebrigii, Flourensia macroligulata and Flourensia heterolepis. Our controlled UV-B experiments, set up in the same natural environment where these species grow, clearly show that solar UV-B - and therefore oxidative stress - is involved in regulating GB contents and within-plant distribution in FC and FO seedlings. The findings in Flourensia co-occurring native species suggest that QACs accumulation may be considered as a community-specific ecophysiological trait in these xerophytic environments. .Fil: Piazza, Leonardo A.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: López, D.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Silva, Mariana Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Lopez Rivilli, Marisa Juana. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cantero, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Tourn, G. M.. Universidad de Buenos Aires. Facultad de Agronomia. Sede Polo Universitario Punilla Centro; ArgentinaFil: Scopel, Ana Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentin

Estimating the mass of galactic components using machine learning algorithms

The estimation of the bulge and disk massses, the main baryonic components of a galaxy, can be performed using various approaches, but their implementation tend to be challenging as they often rely on strong assumptions about either the baryon dynamics or the dark matter model. In this work, we present an alternative method for predicting the masses of galactic components, including the disk, bulge, stellar and total mass, using a set of machine learning algorithms: KNN-neighbours (KNN), Linear Regression (LR), Random Forest (RF) and Neural Network (NN). The rest-frame absolute magnitudes in the ugriz-photometric system were selected as input features, and the training was performed using a sample of spiral galaxies hosting a bulge from Guo's mock catalogue \citep{Guo-Catalog} derived from the Millennium simulation. In general, all the algorithms provide good predictions for the galaxy's mass components ranging from $10^9\,M_\odot$ to $10^{11}\,M_\odot$, corresponding to the central region of the training mass domain; however, the NN give rise to the most precise predictions in comparison to other methods. Additionally, to test the performance of the NN architecture, we used a sample of observed galaxies from the SDSS survey whose mass components are known. We found that the NN can predict the luminous masses of disk-dominant galaxies within the same range of magnitudes that for the synthetic sample up to a $99\%$ level of confidence, while mass components of galaxies hosting larger bulges are well predicted up to $95\%$ level of confidence. The NN algorithm can also bring up scaling relations between masses of different components and magnitudes.Comment: 13 pages, 5 figures and 1 table. Comments are welcom

Fermionic Chern-Simons theory for the Fractional Quantum Hall Effect in Bilayers

We generalize the fermion Chern-Simons theory for the Fractional Hall Effect (FQHE) which we developed before, to the case of bilayer systems. We study the complete dynamic response of these systems and predict the experimentally accessible optical properties. In general, for the so called $(m, m, n)$ states, we find that the spectrum of collective excitations has a gap, and the wave function has the Jastrow-Slater form, with the exponents determined by the coefficients $m$, and $n$. We also find that the $(m,m,m)$ states, {\it i.~e.~}, those states whose filling fraction is $1\over m$, have a gapless mode which may be related with the spontaneous appearance of the interlayer coherence. Our results also indicate that the gapless mode makes a contribution to the wave function of the $(m,m,m)$ states analogous to the phonon contribution to the wave function of superfluid $\rm{He}_4$. We calculate the Hall conductance, and the charge and statistics of the quasiparticles. We also present an $SU(2)$ generalization of this theory relevant to spin unpolarized or partially polarized single layers.Comment: 55 pages, Urbana Prepin

Impact of a Costello Syndrome-Causing Mutation on Learning and Myelin-Producing Cells

Background:Costello Syndrome (CS) is a rare genetic disorder caused by hyperactivating mutations in the HRAS gene, which controls the RAS/MAPK intracellular pathway. Symptoms of CS typically include neurocognitive developmental delays, increased risk of autism spectrum disorder, intellectual disabilities, and other neurological issues. Additionally, most CS patients present with white matter (WM) abnormalities. WM has been proposed to regulate learning due to its roles in increasing/synchronizing action potentials and protecting neuronal axons. Females of a myelin-focused mouse model of CS (PlpCre;HRasG12V; pHRas) show learning deficits in a myelin-regulated test (the complex running wheel; CW) that resolve with time. To shed light onto the mechanisms of these learning deficits, the goal of our study is to describe changes in oligodendrocyte (OL; myelin-producing cells) lineage cells in pHRas mice. Methods: To correlate the cellular and functional impact of HRas mutation on OL lineage (OLL) cells, HRas mutation was induced in mature OLs (mOL) using a tamoxifen-inducible system. Four months after recombination, mice were subjected to the voluntary CW test (a wheel with unevenly spaced rungs), and learning curves were analyzed. An acquisition phase of 14 days was followed by a break from CWs of 3 weeks and a second CW phase of 7 days (memory of skills acquired). After the second exposure to the CW, mice were euthanized, and brain sections were collected for staining with DAPI (nucleated cells), GFP (recombinant cells), PDGFRα (oligodendrocyte precursor cells; OPCs), and Sox10 (OLL cells). Then, cell quantification was performed after conducting confocal imaging. Seven regions of the corpus callosum, across 4 coronal sections, were analyzed for regional differences in the numbers of PDGFR+ OPCs and Sox10+ OLL cells. Results: Our antecedents show that at 2 weeks and 2 months post-mutation, there were significant decreases in distance, average speed, and max speed ran, as well as activity in mutant mice compared to WTs (defective learning curves). However, at 4 months post-mutation, there were no significant differences in learning curves between mutant and WT mice. We then wondered how OPC populations remained at 4 months post-tamoxifen when differences in behavioral phenotypes were no longer detected. We observed that the number of PDGFR+ OPCs decreased in the lateral region of the most anterior coronal section of the corpus callosum, suggesting non-cell-autonomous effects of pHRas on proliferation and/or differentiation of OPCs. Conclusion: Taken together, our results shed light on the role of the HRas mutation on CS mouse models that show transient learning deficits on the CW after the induction of the mutation. Our working hypothesis is that decreased number of OPCs may be a result of an increase in their differentiation into mOLs (to form myelin that restores learning) but lead to a proliferative exhaustion state. We propose an immediate impact (weeks) of HRas mutation on learning that is ameliorated by OPC differentiation \u3c 4 months post-injection. Finding the mechanism of these events can aid in the understanding of this disease and in designing therapeutic treatments based on restoration of myelin function

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

Universal structure of the edge states of the fractional quantum Hall states

We present an effective theory for the bulk fractional quantum Hall states on the Jain sequences on closed surfaces and show that it has a universal form whose structure does not change from fraction to fraction. The structure of this effective theory follows from the condition of global consistency of the flux attachment transformation on closed surfaces. We derive the theory of the edge states on a disk that follows naturally from this globally consistent theory on a torus. We find that, for a fully polarized two-dimensional electron gas, the edge states for all the Jain filling fractions $\nu=p/(2np+1)$ have only one propagating edge field that carries both energy and charge, and two non-propagating edge fields of topological origin that are responsible for the statistics of the excitations. Explicit results are derived for the electron and quasiparticle operators and for their propagators at the edge. We show that these operators create states with the correct charge and statistics. It is found that the tunneling density of states for all the Jain states scales with frequency as $|\omega|^{(1-\nu)/\nu}$.Comment: 10 page

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