Structure of Polyelectrolytes in Poor Solvent

We present simulations on charged polymers in poor solvent. First we investigate in detail the dilute concentration range with and without imposed extension constraints. The resulting necklace polymer conformations are analyzed in detail. We find strong fluctuations in the number of pearls and their sizes leading only to small signatures in the form factor and the force-extension relation. The scaling of the peak in the structure factor with the monomer density shows a pertinent different behavior from good solvent chains.Comment: 7 pages, 5 figures. submitted to EP

Colheita e pós-colheita de castanha de cajueiro-anão precoce na produção integrada de frutas.

O sistema de producao integrada de frutas-PIF objetiva produzir alimentos de alta qualidade, utilizando tecnicas que levem em consideracao os impactos ambientais sobre o sistema solo/água/planta, possibilitando uma agricultura sustentavel e racional. A PIF e regida por normas tecnicas especificas- NTE, que estabelecem parametros para as varias etapas do processo produtivo. As NTEs sao classificadas em quatro ategorias: A-Obrigatorias-requisitos que devem ser cumpridos rigorosamente; B-Recomendadas-requisitos que nao sao obrigatorios, mas que sao recomendados para o sistema; C-Permitidas com restricao- atividades eventualmente permitidas, e D-Proibidas- atividades que nao podem ser realizadas nas areas de producao integrada.bitstream/CNPAT-2010/8141/1/Ci-018.pd

Bioprinting as a food production technique: Conceptual and ethical aspects, advantages and disadvantages, and applications

3D bioprinters present techniques that have various applications in the food industry. For this reason, this work aims to compile and review various research works focused on the utilities and advantages of this type of machinery. Where we first mention the basis of these bioprinting techniques and then proceed to highlight the bioethical issues that surround their application in the food industry, analyze the current advantages and disadvantages, the user that has been given in the production of food for astronauts, and also mention some of the research that has been taking place in Latin America and the world. The greatest advantage of 3D bioprinting of food is the speed of production compared to traditional manufacturing methods, allowing one to obtain food with various geometric shapes; it allows control of the nutritional value, and the texture of the product, reduces environmental pollution and has the advantage of being able to take advantage of the greater performance of the materials required for production. Additionally, this technology is considered an alternative production technique that will be used to solve the problem of feeding in places of scarce resources such as space and areas not suitable for animal husbandry

Determinación de la actividad insecticida de la saponina de la quinua (Chenopodium quinoa) en larvas de Drosophila melanogaster

Chenopodium quinoa es un fitorecurso andino con gran variedad genética y que posee alto valor agronómico-nutritivo, aunque el contenido de saponina otorga un sabor amargo que limita su comercialización; sin embargo, la saponina puede ser aprovechada en otros usos. El presente trabajo evalúa el aprovechamiento del agua de lavado de quinua como fuente de saponina y su empleo como insecticida. La cuantificación de saponina se realizó empleando el método afrosimétrico. La saponina extraída no hidrolizada se identificó mediante cromatografía de capa fina. Para evaluar la natalidad de individuos de D. melanogaster, se les expuso a distintas concentraciones de saponina: 0,1%, 0,4%, 0,7% y 0,9%; así como controles positivo (bórax) y negativo. La electroforesis de proteínas a partir de glándulas salivales e intestino de larvas en tercer estadío de D. melanogaster evidencia notorias diferencias en la expresión de proteínas entre el (T) 0,4% y el resto de tratamientos. En conclusión, la saponina puede ser considerada como un agente que dificulta la supervivencia larval de D. melanogaster debido a que la respuesta frente a éste variará conforme la concentración utilizada. Es recomendable utilizar concentraciones superiores a 0,9% para que la mortalidad sea mayor a 40% de individuos

On the nature of long-range contributions to pair interactions between charged colloids in two dimensions

We perform a detailed analysis of solutions of the inverse problem applied to experimentally measured two-dimensional radial distribution functions for highly charged latex dispersions. The experiments are carried out at high colloidal densities and under low-salt conditions. At the highest studied densities, the extracted effective pair potentials contain long-range attractive part. At the same time, we find that for the best distribution functions available the range of stability of the solutions is limited by the nearest neighbour distance between the colloidal particles. Moreover, the measured pair distribution functions can be explained by purely repulsive pair potentials contained in the stable part of the solution.Comment: 6 pages, 5 figure

Like-charge attraction through hydrodynamic interaction

We demonstrate that the attractive interaction measured between like-charged colloidal spheres near a wall can be accounted for by a nonequilibrium hydrodynamic effect. We present both analytical results and Brownian dynamics simulations which quantitatively capture the one-wall experiments of Larsen and Grier (Nature 385, p. 230, 1997).Comment: 10 pages, 4 figure

Effect of titanium foliar applications on tomato fruits from plants grown under salt stress conditions

Salt stress affects plant metabolism, while beneficial elements such as titanium (Ti) may stimulate adaptive responses to mitigate salt stress. Here we evaluated the main effects of sodium chloride (NaCl 0, 50 and 100 mM) in the nutrient solution, and of titanium foliar spray (Ti 0.75 and 150 mg L-1), as well as the interaction of these study factors, on tomato cv. ‘Rio Supremo’ performance in greenhouse. Plants were treated with NaCl during 80 d through automated drip irrigation; while eight Ti foliar sprayings were applied with a manual sprayer, at intervals of 10 d each. Yield and quality parameters of fruits were evaluated in the second cluster. NaCl reduced yield parameters, pH value and increased the titratable acidity (TA), electrical conductivity (EC), and total soluble solids (TSS), as well as the TSS/TA ration in the fruits. Ti did not affect yield parameters, though it reduced the pH and increased the TSS/TA ratio of fruits. NaCl and Ti have differential effects on fruit quality as separate factors, while the interaction of both factors revealed that Ti effects dependent on the presence of NaCl and its level in the nutrient solution. In conclusion, Ti did not mitigate the negative effects of saline stress on the evaluated yield parameters, but importantly, with moderate levels of NaCl in the nutrient solution (50 mM), Ti increased EC, TA and TSS of fruits

Age-dependent multisystem parkinsonian features in a novel neuromelanin-producing transgenic mouse model

Trabajo presentado en el 19th National Meeting of the Spanish Society of Neuroscience, celebrado en Lleida (España), del 3 al 5 de noviembre de 2021Parkinson’s disease (PD) is characterized by a preferential degeneration of neurons that accumulate with age the pigment neuromelanin, especially neurons from substantia nigra (SN) and locus coeruleus (LC). We aim to characterize the consequences of age-dependent intracellular neuromelanin accumulation in catecholaminergic neuronal populations to understand the relationship between this process and the vulnerability of these cells in PD, as well as its impact on healthy brain aging. We previously generated a rat model exhibiting progressive unilateral SN production of neuromelanin that showed parkinsonian-like neuropathology and motor deficits1. Here, we generated a new neuromelanin-producing rodent model, based on the tissue-specific constitutive expression of human tyrosinase (hTyr) under the tyrosine hydroxylase (TH) promoter (Tg-TH-hTyr), that mimics the bilateral distribution of pigmentation within the aging human brain (i.e. catecholaminergic groups A1-A142). In parallel to neuromelanin intracellular buildup, Tg-TH-hTyr mice exhibited major PD features, including motor and non-motor behavioral alterations, inclusion body formation and degeneration of specific catecholaminergic neuronal groups. Genome-wide transcriptomic analysis of neuromelanin-laden neurons revealed alterations in PD-related biological pathways that correlate with human PD postmortem studies. Our results show that modelling human neuromelanin accumulation in rodents leads to age-dependent catecholaminergic dysfunction and molecular alterations resulting in motor and non-motor deficits, which is relevant to PD pathology and brain aging.Peer reviewe

A parallel-group, multicenter randomized, double-blinded, placebo-controlled, phase 2/3, clinical trial to test the efficacy of pyridostigmine bromide at low doses to reduce mortality or invasive mechanical ventilation in adults with severe SARS-CoV-2 infection: the Pyridostigmine In Severe COvid-19 (PISCO) trial protocol

© 2020, The Author(s). Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the causative agent of coronavirus disease 2019 (COVID-19), may lead to severe systemic inflammatory response, pulmonary damage, and even acute respiratory distress syndrome (ARDS). This in turn may result in respiratory failure and in death. Experimentally, acetylcholine (ACh) modulates the acute inflammatory response, a neuro-immune mechanism known as the inflammatory reflex. Recent clinical evidence suggest that electrical and chemical stimulation of the inflammatory reflex may reduce the burden of inflammation in chronic inflammatory diseases. Pyridostigmine (PDG), an ACh-esterase inhibitor (i-ACh-e), increases the half-life of endogenous ACh, therefore mimicking the inflammatory reflex. This clinical trial is aimed at evaluating if add-on of PDG leads to a decrease of invasive mechanical ventilation and death among patients with severe COVID-19. Methods: A parallel-group, multicenter, randomized, double-blinded, placebo-controlled, phase 2/3 clinical trial to test the efficacy of pyridostigmine bromide 60 mg/day P.O. to reduce the need for invasive mechanical ventilation and mortality in hospitalized patients with severe COVID-19. Discussion: This study will provide preliminary evidence of whether or not -by decreasing systemic inflammation- add-on PDG can improve clinical outcomes in patients with severe COVID-19. Trial registration: ClinicalTrials.gov NCT04343963 (registered on April 14, 2020)