Photodetector with integrated optical thin film filters

This paper reports on optical filters based on a-SiC:H tandem pi'n/pin heterostructures. The spectral sensitivity is analyzed. Steady state optical bias with different wavelengths are applied from each front and back sides and the photocurrent is measured. Results show that it is possible to control the sensitivity of the device and to tune a specific wavelength range by combining radiations with complementary light penetration depths. The transfer characteristics effects due to changes in the front and back optical bias wavelength are discussed. Depending on the wavelength of the external background and irradiation side, the device acts either as a short- or a long-pass band filter or as a band-stop filter. The output waveform presents a nonlinear amplitude-dependent response to the wavelengths of the input channels

Carbon monoxide prevents hepatic mitochondrial membrane permeabilization

<p>Abstract</p> <p>Background</p> <p>Low concentrations of carbon monoxide (CO) protect hepatocytes against apoptosis and confers cytoprotection in several models of liver. Mitochondria are key organelles in cell death control <it>via </it>their membrane permeabilization and the release of pro-apoptotic factors.</p> <p>Results</p> <p>Herein, we show that CO prevents mitochondrial membrane permeabilization (MMP) in liver isolated mitochondria. Direct and indirect approaches were used to evaluate MMP inhibition by CO: mitochondrial swelling, mitochondrial depolarization and inner membrane permeabilization. Additionally, CO increases mitochondrial reactive oxygen species (ROS) generation, and their scavenging, by ß-carotene addition, decreases CO protection, which reveals the key role of ROS. Interestingly, cytochrome c oxidase transiently responds to low concentrations of CO by decreasing its activity in the first 5 min, later on there is an increase of cytochrome c oxidase activity, which were detected up to 30 min.</p> <p>Conclusion</p> <p>CO directly prevents mitochondrial membrane permeabilization, which might be implicated in the hepatic apoptosis inhibition by this gaseoustransmitter.</p

Biologia do pseudanto de Dalechampia aff. triphylla Lam. (Euphorbiaceae) e sua polinização por abelhas (Apidae, Meliponina)

The main goals of this study were investigate the morphology and biology of Dalechampia aff. triphylla pseudanthium and its potential pollinators. The species occurs in Viçosa, southeastern Brazil and is a ruderal species. The production of flowers and fruits occurred during the whole year of study. Two green involucral bracts and two subinflorescences, one female and other male, constitute the pseudanthium. The male subinflorescence contains staminate flowers and a resiniferous gland. The pseudanthia are protogynous, with an initial female phase, which lasted 1,7 days, followed by a bisexual phase, which lasted 9,1 days. The involucral bracts opened every day by the morning and closed around 19:00h. During the female phase, bract opens between 9:00 and 11:00h, while in the bisexual phase it opens between 6:00 and 7:00h. This anticipates opening of involucral bracts of pseudanthia in bisexual phase seems to favor pollen transference by pollinators, to pseudanthia in female phase. D. aff. triphylla is visited by four species of stingless bees, Friesella schrottkyi, Plebeia droryana, Plebeia sp., Tetragonisca angustula. All of them were potential pollinators of the species, and that is for the first time reported for a Dalechampia species. These bees have their body length as long as stigma-resin gland distance so they are capable of fertilize stigmas during resin collection. Finally, continuous flowering, visiting behavior of pollinators, differential timing of involucral bracts opening according to pseudanthium phase, and extended duration of the bisexual phase are factors that contribute to the reproductive success of D. aff. triphylla.Este estudo objetivou investigar a morfologia e a biologia do pseudanto de Dalechampia aff. triphylla e seus potenciais polinizadores. A espécie ocorre em Viçosa, Minas Gerais, é ruderal e autocompatível. A produção de flores e frutos ocorreu durante todo o ano de estudo. O pseudanto é constituído por duas brácteas involucrais e sub-inflorescências, feminina e masculina. A sub-inflorescência masculina é composta por flores estaminadas e uma glândula de resina. O pseudanto é protogínico. A fase feminina perdura 1,7 dias, seguida por uma fase bissexuada que perdura por 9,1 dias. As brácteas involucrais se abrem todos os dias pela manhã e se fecham por volta das 19h00min. Na fase feminina, as brácteas se abrem entre as 09h00min e 11h00min, enquanto que na fase bissexuada das 06h00min, 07h00min. Esta abertura antecipada das brácteas involucrais durante a fase bissexuada indica um favorecimento da transferência de pólen por polinizadores, para pseudantos na fase feminina. D. aff. triphylla é visitada por quatro espécies de abelhas sem ferrão: Friesella schrottkyi, Plebeia droryana, Plebeia sp., Tetragonisca angustula e pela primeira vez estas espécies são relatadas como polinizadores de uma espécie de Dalechampia. O comprimento do corpo destas abelhas é suficiente para fertilizar o estigma durante a coleta de resina. Além disto, a floração contínua, o comportamento das abelhas na visita às flores, a diferenciação da hora de abertura das brácteas involucrais de acordo com a fase do pseudanto, e a longa duração da fase bissexuada são fatores que contribuem para o sucesso reprodutivo de D. aff. triphylla

Influence of abiotic factors on the chemical composition of copaiba oil (Copaifera multijuga Hayne): soil composition, seasonality and diameter at breast height

Copaiba oils are important medicinal products used primarily for their healing and anti-inflammatory activities. Consisting of sesquiterpenes and diterpenes, these oils have variable composition which, according to the literature, may originate from several factors. In order to analyze the relationship between chemical composition and abiotic factors such as seasonality, diameter at breast height (DBH) and soil composition, sixteen of oilresin samples of Copaifera multijuga Hayne, from the Ducke Forest Reserve (Manaus City, Amazon State, Brazil), were analyzed by gas chromatography with flame ionization detection (GC-FID) and coupled with mass spectrometry (GC-MS). Thirty-five compounds were identified and the results evaluated by multivariate analysis (hierarchical cluster analysis (HCA) and principal component analysis (PCA)), allowing differentiation of the samples into two groups with different compositions. One of them presented &#946;-caryophyllene as the major constituent, while the other presented caryophyllene oxide. This variation in composition appears to depend on soil type. Other factors previously described as essential for defining the chemical composition of copaiba oils, such as seasonality and DBH, showed no significant influence on the chemical composition of oils of this species

Impairment of energy metabolism in hippocampus of rats subjected to chemically-induced hyperhomocysteinemia

AbstractHomocystinuria is an inherited metabolic disease biochemically characterized by tissue accumulation of homocysteine (Hcy). Mental retardation, ischemia and other neurological features, whose mechanisms are still obscure are common symptoms in homocystinuric patients. In this work, we investigated the effect of Hcy administration in Wistar rats on some parameters of energy metabolism in the hippocampus, a cerebral structure directly involved with cognition. The parameters utilized were 14CO2 production, glucose uptake, lactate release and the activities of succinate dehydrogenase and cytochrome c oxidase (COX). Chronic hyperhomocysteinemia was induced by subcutaneous administration of Hcy twice a day from the 6th to the 28th day of life in doses previously determined in our laboratory. Control rats received saline in the same volumes. Rats were killed 12 h after the last injection. Results showed that Hcy administration significantly diminished 14CO2 production and glucose uptake, as well as succinate dehydrogenase and COX activities. It is suggested that impairment of brain energy metabolism may be related to the neurological symptoms present in homocystinuric patients

Paracrine effect of carbon monoxide - astrocytes promote neuroprotection through purinergic signaling in mice

© 2016. Published by The Company of Biologists Ltd.The neuroprotective role of carbon monoxide (CO) has been studied in a cell-autonomous mode. Herein, a new concept is disclosed - CO affects astrocyte-neuron communication in a paracrine manner to promote neuroprotection. Neuronal survival was assessed when co-cultured with astrocytes that had been pre-treated or not with CO. The CO-pre-treated astrocytes reduced neuronal cell death, and the cellular mechanisms were investigated, focusing on purinergic signaling. CO modulates astrocytic metabolism and extracellular ATP content in the co-culture medium. Moreover, several antagonists of P1 adenosine and P2 ATP receptors partially reverted CO-induced neuroprotection through astrocytes. Likewise, knocking down expression of the neuronal P1 adenosine receptor A2A-R (encoded by Adora2a) reverted the neuroprotective effects of CO-exposed astrocytes. The neuroprotection of CO-treated astrocytes also decreased following prevention of ATP or adenosine release from astrocytic cells and inhibition of extracellular ATP metabolism into adenosine. Finally, the neuronal downstream event involves TrkB (also known as NTRK2) receptors and BDNF. Pharmacological and genetic inhibition of TrkB receptors reverts neuroprotection triggered by CO-treated astrocytes. Furthermore, the neuronal ratio of BDNF to pro-BDNF increased in the presence of CO-treated astrocytes and decreased whenever A2A-R expression was silenced. In summary, CO prevents neuronal cell death in a paracrine manner by targeting astrocytic metabolism through purinergic signaling.publishersversionpublishe

Solvent and temperature effects on the solubility of syringic, vanillic or veratric acids: Experimental, modeling and solid phase studies

The solubility of syringic acid, vanillic acid and veratric acid was measured in pure water and eleven organic solvents (methanol, ethanol, 1-propanol, 2-propanol, 2-butanone, ethyl acetate, acetonitrile, dimethylformamide, 1,2-propanediol, 1,3-propanediol and 1,3-butanediol), at 298.2 K and 313.2 K. Besides the solubility data, the melting temperatures and enthalpies of the solutes were determined by differential scanning calorimetry, while powder and single X-ray diffractionwere used to resolve the solute solid structure, before and after the solubility studies. Formodeling purposes, theNRTL-SACmodel, also combinedwith the Reference Solvent Approach (RSA), and the Abraham solvation model were applied to describe the solid-liquid equilibria of the binary systems. A set of solvents was used to estimate the model parameters and afterwards, solubility predictions were carried out for binary systems not included in the correlation step. Better results were obtained using the Abraham solvation model with average relative deviations (ARD) of 15% for the correlation set and 26% for the predictions, which are more satisfactory than the results found with the NRTL-SAC model (33% for the correlation and 59% for the predictions) or the NRTL-SAC model combined with RSA (30% for the correlation and 59% for the predictions).We acknowledge the support of the project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER- 000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC); UID/CTM/50011/2019 (CICECO), financed by national funds through the FCT/MCTES; and project AllNat - POCI-01- 0145-FEDER-030463 (PTDC/EQU-EPQ/30463/2017), financed by FEDER funds through COMPETE and Portugal2020 and national funds through FCT - Fundação para a Ciência e a Tecnologia. The authors also thank FCT for financial support to S. M. Vilas-Boas grant (SFRH/BD/138149/2018) and V. Vieira grant (SFRH/BD/108487/ 2015).info:eu-repo/semantics/publishedVersio

Serological and molecular evidence of hepatitis B vírus infection in swine from Brazil.

Projeto/Plano de Ação: 02.11.01.006

Host Susceptibility to Brucella abortus Infection Is More Pronounced in IFN-γ knockout than IL-12/β2-Microglobulin Double-Deficient Mice

Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and CD8+ T lymphocytes are important components of host immune responses against B. abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be more critical to control B. abortus infection compared to the lack of endogenous IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed increased numbers of bacterial load in spleens; however, at 3 weeks postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO animals to Brucella was associated to undetectable levels of IFN-γ in mouse splenocytes and inability of these cells to lyse Brucella-infected macrophages. However, the lack of endogenous IFN-γ was found to be more important to control brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies