Breakdown of the lattice polaron picture in La0.7Ca0.3MnO3 single crystals

When heated through the magnetic transition at Tc, La0.7Ca0.3MnO3 changes from a band metal to a polaronic insulator. The Hall constant R_H, through its activated behavior and sign anomaly, provides key evidence for polaronic behavior. We use R_H and the Hall mobility to demonstrate the breakdown of the polaron phase. Above 1.4Tc, the polaron picture holds in detail, while below, the activation energies of both R_H and the mobility deviate strongly from their polaronic values. These changes reflect the presence of metallic, ferromagnetic fluctuations, in the volume of which the Hall effect develops additional contributions tied to quantal phases.Comment: 11 pages, 3 figures, final version to appear in Phys. Rev. B Rapi

Prevalencia de gingivitis inducida por biofilm dental en escolares con discapacidad intelectual de la Unidad Educativa Especial del Azuay y de la Escuela de Educación Básica Fiscomisional San José de Calasanz en la ciudad de Cuenca – Ecuador

Este estudio tuvo como objetivo determinar la prevalencia de gingivitis asociada a biofilm dental en escolares con discapacidad intelectual de la Unidad Educativa Especial del Azuay y de la Escuela de Educación Básica Fiscomisional San José de Calasanz en la ciudad de Cuenca – Ecuador durante el período marzo 2018 - marzo 2019. El estudio fue de tipo descriptivo transversal en el que se analizó una muestra de 133 escolares con retraso mental, síndrome de Down y autismo entre los 3 y 20 años de edad. Se valoró calidad de higiene (Índice de O’Leary) y estado gingival (Índice gingival de Löe y Sillness y datos de periodontograma basados en la clasificación de enfermedades gingivales inducidas por biofilm) para identificar presencia de condiciones gingivales asociadas a biopelícula. En el estudio participaron 65 mujeres (48,87%) y 68 hombres (51,13%), de los cuales el 51,88% se ubicó dentro de una discapacidad cognitiva leve. Acorde al índice de O’Leary se evidenció que el 100% de los participantes presentaron higiene deficiente, y al relacionarlo con el índice gingival de Löe y Sillnes se demostró una prevalencia de gingivitis moderada del 58,65%. Únicamente se encontró una persona con encía sana (0,75%). Con respecto a la clasificación de enfermedades gingivales de Armitage, una frecuencia de 68 participantes (51.13%) presentó gingivitis localizada. En conclusión, se observa una alta prevalencia de enfermedad gingival en la población evaluada, demostrando un estado de higiene oral inadecuado donde el 99,25% de personas con discapacidad intelectual analizadas en el estudio mostraron indicadores de gingivitis, sin diferencias en la salud gingival entre los dos grupos de escolares.The aim of this study was to determine the prevalence of gingivitis associated with dental biofilm in students with intellectual disabilities from “Unidad Educativa Especial del Azuay” and “Escuela de Educación Básica Fiscomisional San José de Calasanz” in the city of Cuenca - Ecuador during the period March 2018 - March 2019. It consists of a descriptive cross-sectional study, which analyzed 133 students with mental retardation, Down syndrome and autism between 3 and 20 years old. The quality of hygiene (O'Leary Index) and gingival status (Löe and Sillness Gingival Index and periodontogram data based on the classification of biofilm-induced gum diseases) were evaluated to identify the presence of gingival conditions associated with biofilm. The study included 65 women (48.87%) and 68 men (51.13%), of whom 51.88% were located within a mild cognitive disability. According to the O'Leary index, it was evidenced that 100% of the participants had poor hygiene, and when relating it to the Löe and Sillnes gingival index, a prevalence of moderate gingivitis was demonstrated at 58.65%. Only one person with healthy gums was found (0.75%). Regarding the Armitage classification of gingival diseases, a frequency of 68 participants (51.13%) presented localized gingivitis. In conclusion a high prevalence of gum disease is observed in the population evaluated, demonstrating an inadequate oral hygiene state where 99.25% of people with intellectual disabilities analyzed in the study presented indicators of gingivitis, with no differences in gingival health between the two groups of students.OdontólogoCuenc

Improvements to the APBS biomolecular solvation software suite

The Adaptive Poisson-Boltzmann Solver (APBS) software was developed to solve the equations of continuum electrostatics for large biomolecular assemblages that has provided impact in the study of a broad range of chemical, biological, and biomedical applications. APBS addresses three key technology challenges for understanding solvation and electrostatics in biomedical applications: accurate and efficient models for biomolecular solvation and electrostatics, robust and scalable software for applying those theories to biomolecular systems, and mechanisms for sharing and analyzing biomolecular electrostatics data in the scientific community. To address new research applications and advancing computational capabilities, we have continually updated APBS and its suite of accompanying software since its release in 2001. In this manuscript, we discuss the models and capabilities that have recently been implemented within the APBS software package including: a Poisson-Boltzmann analytical and a semi-analytical solver, an optimized boundary element solver, a geometry-based geometric flow solvation model, a graph theory based algorithm for determining p$K_a$ values, and an improved web-based visualization tool for viewing electrostatics

Colossal Magnetoresistance is a Griffiths Singularity

It is now widely accepted that the magnetic transition in doped manganites that show large magnetoresistance is a type of percolation effect. This paper demonstrates that the transition should be viewed in the context of the Griffiths phase that arises when disorder suppresses a magnetic transition. This approach explains unusual aspects of susceptibility and heat capacity data from a single crystal of La$_{0.7}$Ca$_{0.3}$MnO$_{3}.$Comment: 4 page

The Impact of Aerobic Exercise on Fronto-Parietal Network Connectivity and Its Relation to Mobility: An Exploratory Analysis of a 6-Month Randomized Controlled Trial

Impaired mobility is a major concern for older adults and has significant consequences. While the widely accepted belief is that improved physical function underlies the effectiveness of targeted exercise training in improving mobility and reducing falls, recent evidence suggests cognitive and neural benefits gained through exercise may also play an important role in promoting mobility. However, the underlying neural mechanisms of this relationship are currently unclear. Thus, we hypothesize that 6 months of progressive aerobic exercise training would alter frontoparietal network (FPN) connectivity during a motor task among older adults with mild subcortical ischemic vascular cognitive impairment (SIVCI)—and exercise-induced changes in FPN connectivity would correlate with changes in mobility. We focused on the FPN as it is involved in top-down attentional control as well as motor planning and motor execution. Participants were randomized either to usual-care (CON), which included monthly educational materials about VCI and healthy diet; or thrice-weekly aerobic training (AT), which was walking outdoors with progressive intensity. Functional magnetic resonance imaging was acquired at baseline and trial completion, where the participants were instructed to perform bilateral finger tapping task. At trial completion, compared with AT, CON showed significantly increased FPN connectivity strength during right finger tapping (p < 0.05). Across the participants, reduced FPN connectivity was associated with greater cardiovascular capacity (p = 0.05). In the AT group, reduced FPN connectivity was significantly associated with improved mobility performance, as measured by the Timed-Up-and-Go test (r = 0.67, p = 0.02). These results suggest progressive AT may improve mobility in older adults with SIVCI via maintaining intra-network connectivity of the FPN

Evidence against a Role of Elevated Intracellular Ca2+ during Plasmodium falciparum Preinvasion.

Severe malaria is primarily caused by Plasmodium falciparum parasites during their asexual reproduction cycle within red blood cells. One of the least understood stages in this cycle is the brief preinvasion period during which merozoite-red cell contacts lead to apical alignment of the merozoite in readiness for penetration, a stage of major relevance in the control of invasion efficiency. Red blood cell deformations associated with this process were suggested to be active plasma membrane responses mediated by transients of elevated intracellular calcium. Few studies have addressed this hypothesis because of technical challenges, and the results remained inconclusive. Here, Fluo-4 was used as a fluorescent calcium indicator with optimized protocols to investigate the distribution of the dye in red blood cell populations used as P. falciparum invasion targets in egress-invasion assays. Preinvasion dynamics was observed simultaneously under bright-field and fluorescence microscopy by recording egress-invasion events. All the egress-invasion sequences showed red blood cell deformations of varied intensities during the preinvasion period and the echinocytic changes that follow during invasion. Intraerythrocytic calcium signals were absent throughout this interval in over half the records and totally absent during the preinvasion period, regardless of deformation strength. When present, calcium signals were of a punctate modality, initiated within merozoites already poised for invasion. These results argue against a role of elevated intracellular calcium during the preinvasion stage. We suggest an alternative mechanism of merozoite-induced preinvasion deformations based on passive red cell responses to transient agonist-receptor interactions associated with the formation of adhesive coat filaments

Deletion of lysophosphatidic acid receptor LPA1 reduces neurogenesis in the mouse dentate gyrus

Neurogenesis persists in certain regions of the adult brain including the subgranular zone of the hippocampal dentate gyrus wherein its regulation is essential, particularly in relation to learning, stress and modulation of mood. Lysophosphatidic acid (LPA) is an extracellular signaling phospholipid with important neural regulatory properties mediated by specific G protein-coupled receptors, LPA1–5. LPA1 is highly expressed in the developing neurogenic ventricular zone wherein it is required for normal embryonic neurogenesis, and, by extension may play a role in adult neurogenesis as well. By means of the analyses of a variant of the original LPA1-null mutant mouse, termed the Malaga variant or “maLPA1-null,” which has recently been reported to have defective neurogenesis within the embryonic cerebral cortex, we report here a role for LPA1 in adult hippocampal neurogenesis. Proliferation, differentiation and survival of newly formed neurons are defective in the absence of LPA1 under normal conditions and following exposure to enriched environment and voluntary exercise. Furthermore, analysis of trophic factors in maLPA1-null mice demonstrated alterations in brain-derived neurotrophic factor and insulin growth factor 1 levels after enrichment and exercise. Morphological analyses of doublecortin positive cells revealed the anomalous prevalence of bipolar cells in the subgranular zone, supporting the operation of LPA1 signaling pathways in normal proliferation, maturation and differentiation of neuronal precursors

Correlation between Targeted qPCR Assays and Untargeted DNA Shotgun Metagenomic Sequencing for Assessing the Fecal Microbiota in Dogs

DNA shotgun sequencing is an untargeted approach for identifying changes in relative abundances, while qPCR allows reproducible quantification of specific bacteria. The canine dysbiosis index (DI) assesses the canine fecal microbiota by using a mathematical algorithm based on qPCR results. We evaluated the correlation between qPCR and shotgun sequencing using fecal samples from 296 dogs with different clinical phenotypes. While significant correlations were found between qPCR and sequencing, certain taxa were only detectable by qPCR and not by sequencing. Based on sequencing, less than 2% of bacterial species (17/1190) were consistently present in all healthy dogs (n = 76). Dogs with an abnormal DI had lower alpha-diversity compared to dogs with normal DI. Increases in the DI correctly predicted the gradual shifts in microbiota observed by sequencing: minor changes (R = 0.19, DI 2, DI > 5, and DI > 8, respectively), compared to dogs with a normal DI (DI < 0, all targets within the RI), as higher R-values indicated larger dissimilarities. In conclusion, the qPCR-based DI is an effective indicator of overall microbiota shifts observed by shotgun sequencing in dogs

Flavanols and Anthocyanins in Cardiovascular Health: A Review of Current Evidence

Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects of these food bioactives may be driven by two of their characteristic properties: their affinity for proteins and their antioxidant activity. Over the last 15 years, numerous publications have demonstrated that besides their in vitro antioxidant capacity, certain phenolic compounds, such as anthocyanins, catechins, proanthocyanidins, and other non coloured flavonoids, may regulate different signaling pathways involved in cell survival, growth and differentiation. In this review we will update the knowledge on the cardiovascular effects of anthocyanins, catechins and proanthocyanidins, as implied by the in vitro and clinical studies on these compounds. We also review the available information on the structure, distribution and bioavailability of flavanols (monomeric catechins and proanthocyanidins) and anthocyanins, data necessary in order to understand their role in reducing risk factors and preventing cardiovascular health problems through different aspects of their bioefficacy on vascular parameters (platelet agregation, atherosclerosis, blood pressure, antioxidant status, inflammation-related markers, etc.), myocardial conditions, and whole-body metabolism (serum biochemistry, lipid profile), highlighting the need for better-designed clinical studies to improve the current knowledge on the potential health benefits of these flavonoids to cardiovascular and metabolic health