Comparação de métodos de cálculo do teor de lipídeos em frutos de tucumã (Astrocaryum vulgare).

Neste momento a agricultura brasileira vê-se frente à necessidade de ampliar e diversificar a produção de óleos vegetais devido a fortes demandas dos mercados de alimentos e biocombustíveis. Em função disto, foi lançado em 2010 o programa PALMA DE ÓLEO com incentivos para a produção de óleo de palma (dendê) na Amazônia e Costa do Dendê na Bahia. Além disso, em função de demandas do governo federal, a Embrapa executa o projeto PROPALMA que tem como objetivos gerar tecnologias para a produção de óleos a partir de palmeiras tais como inajá, babaçu, macaúba e tucumã. Este trabalho teve como objetivo comparar duas formas de determinação do teor de lipídeos em amostra de tucumã visando desenvolver uma metodologia mais rápida para tal determinação. A extração de lipídeos foi efetuada pelo método soxleth e os teores de lipídeos foram determinados a partir da pesagem do óleo extraído nos balões e da pesagem dos cartuchos de amostras após a extração. Os resultados entre estes dois métodos foram comparados e não mostraram diferenças significativas para teores de óleo na faixa de 20% a 50%.PIBIC-2011

Mitochondrial- and Endoplasmic Reticulum-Associated Oxidative Stress in Alzheimer's Disease: From Pathogenesis to Biomarkers

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, affecting several million of people worldwide. Pathological changes in the AD brain include the presence of amyloid plaques, neurofibrillary tangles, loss of neurons and synapses, and oxidative damage. These changes strongly associate with mitochondrial dysfunction and stress of the endoplasmic reticulum (ER). Mitochondrial dysfunction is intimately linked to the production of reactive oxygen species (ROS) and mitochondrial-driven apoptosis, which appear to be aggravated in the brain of AD patients. Concomitantly, mitochondria are closely associated with ER, and the deleterious crosstalk between both organelles has been shown to be involved in neuronal degeneration in AD. Stimuli that enhance expression of normal and/or folding-defective proteins activate an adaptive unfolded protein response (UPR) that, if unresolved, can cause apoptotic cell death. ER stress also induces the generation of ROS that, together with mitochondrial ROS and decreased activity of several antioxidant defenses, promotes chronic oxidative stress. In this paper we discuss the critical role of mitochondrial and ER dysfunction in oxidative injury in AD cellular and animal models, as well as in biological fluids from AD patients. Progress in developing peripheral and cerebrospinal fluid biomarkers related to oxidative stress will also be summarized

Effect of chronic exposure to aluminium on isoform expression and activity of rat (Na+/K+)ATPase

The ability of aluminum to inhibit the (Na+/K+)ATPase activity has been observed by several investigators. The (Na+/K+)ATPase is characterized by a complex molecular heterogeneity that results from the expression and differential association of multiple isoforms of both catalytic (alpha) and regulatory (beta) subunits. For instance, three main alpha (alpha(1), alpha(2) and alpha(3)) and three beta (beta(1), beta(2) and beta(3)) subunit isoforms exist in vertebrate nervous tissue, whereas only alpha(1) and beta(1) have been identified in kidney. However, no studies have focused on determining the change in (Na+/K+)ATPase isoforms caused by chronic exposure to aluminum and its relation with aluminum toxicity. In this study, adult male Wistar rats were submitted to chronic dietary AlCl3 exposure (0.03 g/day of AlCl3 for 4 months), and the activity and protein expression of (Na+/K+)ATPase isozymes were studied in brain cortex synaptosomes and in kidney homogenates. The intracellular levels of adenine nucleotides, plasma membrane integrity, and aluminum accumulation were also studied in brain synaptosomes. Aluminum accumulation upon chronic dietary AlCl3 administration significantly decreased the (Na+/K+)ATPase activity measured in the presence of nonlimiting Mg-ATP concentrations, without compromising protein expression of alpha-subunit isoforms in brain and kidney. Aluminum-induced synaptosomal (Na+/K+)ATPase inhibition was due to a reduction in the activity of isozymes containing alpha(1)-alpha(2) and alpha(3)-subunits. The onset of enzyme inhibition was accompanied by a decrease of the (Na+/K+)ATPase sensitivity to submicromolar concentrations of ouabain, and it preceded major damage in plasma membrane integrity and energy supply, as revealed by the analysis of lactate dehydrogenase leakage and endogenous adenine nucleotides. The data suggest that, during chronic dietary exposure to AlCl3, brain (Na+/K+)ATPase activity drops, even if no significant alterations of catalytic subunit protein expression, cellular energy depletion, and changes in cell membrane integrity are observed. Implications regarding underlying mechanisms of aluminum neurotoxicity are discussed.FCTPOCTI/BSE/46721/2002BD/21343/9

On zooplankton of the coastal waters of Rio Grande Do Norte sampled from oil producing platform

Lack of a comprehensive knowledge of zooplankton of the coastal waters of the northeast region of Brazil prompted the present study. Seasonal and diurnal collections were made from an oil producing platform located off Ouamari, Rio Grande do Norte, %azi! during the period of one year from March 1987 to February 1988. A pneliminary analysis of the samples showed a discernible seasonal fluctu* atioD and a clear pattern of diurnal changes in the composition of zooplankton

Assessment of portuguese community forestry: using the Voluntary Guidelines on the Responsible Governance of Tenure and FAO community-based forestry framework

In the last five decades, Community-Based Forestry (CBF) has become a subject of special attention. It is assumed that the transfer of rights to local communities will improve forest management. In Portugal more than 13% of the forest area belongs to local communities (termed baldios). Following FAO tools, assessments of Forest Tenure and CBF were conducted to evaluate the effectiveness of four baldio management types. The results revealed the most common challenges for baldios, vis- a-vis, rights associated with their management, protection of these rights, weak land administration, weak mechanisms for conflict resolution, problems with decentralized state support, cash flow management, and environmental challenges leading to wildfires, loss of biodiversity, and inadequate control of pests and invasive species. Resolution of these challenges is urgently needed at the legal, administrative and local levels. Future research should include assessments of CBF in other European countries to reduce the existing knowledge gapinfo:eu-repo/semantics/publishedVersio

Absolute Hyperglycemia versus Stress Hyperglycemia Ratio for the Prognosis of Hospitalized Patients with COVID-19 in the First Months of the Pandemic: A Retrospective Study

Diabetes is a risk factor for greater severity of coronavirus disease 2019 (COVID-19). The stress hyperglycemia ratio (SHR) is an independent predictor of critical illness, and it is reported to have a stronger association than absolute hyperglycemia. The aim of this study was to assess the relationship of absolute hyperglycemia and SHR with the severity of COVID-19, since there are no studies investigating SHR in patients with COVID-19. We conducted a retrospective observational study on hospitalized patients with COVID-19 in the first months of the pandemic, regarding absolute hyperglycemia, SHR, and severity outcomes. Of the 374 patients, 28.1% had a previous diagnosis of type 2 diabetes. Absolute hyperglycemia (64.8% versus 22.7%; p < 0.01) and SHR [1.1 (IQR 0.9-1.3) versus 1.0 (IQR 0.9-1.2); p < 0.001] showed a statistically significant association with previous diabetes. Absolute hyperglycemia showed a significant association with clinical severity of COVID-19 (79.0% versus 62.7%; p < 0.001), need for oxygen therapy (74.8% versus 54.4%; p < 0.001), invasive mechanical ventilation (28.6% versus 11.6%; p < 0.001), and intensive care unit (30.3% versus 14.9%; p = 0.002), but not with mortality; by contrast, there was no statistically significant association between SHR and all these parameters. Our results are in agreement with the literature regarding the impact of absolute hyperglycemia on COVID-19 severity outcomes, while SHR was not a significant marker. We therefore suggest that SHR should not be evaluated in all patients admitted in the hospital for COVID-19, and we encourage the standard measures at admission of blood glucose and HbA1c levels.info:eu-repo/semantics/publishedVersio

Efeitos de sistemas de condução e porta-enxerto sobre a produção e qualidade da uva Cheninc Blanc no Vale do São Francisco: 4. ciclo de produção.

Este trabalho teve como objetivo avaliar os efeitos de sistemas de condução e do porta-enxerto sobre os componentes de produção e qualidade da uva Cheninc Blanc durante o 4. ciclo de produção no Vale do São Francisco

On the low-temperature lattice thermal transport in nanowires

We propose a theory of low temperature thermal transport in nano-wires in the regime where a competition between phonon and flexural modes governs the relaxation processes. Starting with the standard kinetic equations for two different types of quasiparticles we derive a general expression for the coefficient of thermal conductivity. The underlying physics of thermal conductance is completely determined by the corresponding relaxation times, which can be calculated directly for any dispersion of quasiparticles depending on the size of a system. We show that if the considered relaxation mechanism is dominant, then at small wire diameters the temperature dependence of thermal conductivity experiences a crossover from $T^{1/2}$ to $T^3$-dependence. Quantitative analysis shows reasonable agreement with resent experimental results.Comment: 12 pages, 3 eps figure

Phonon-mediated thermal conductance of mesoscopic wires with rough edges

We present an analysis of acoustic phonon propagation through long, free-standing, insulating wires with rough surfaces. Due to a crossover from ballistic propagation of the lowest-frequency phonon mode at $\omega <\omega _{1}=\pi c/W$ to a diffusive (or even localized) behavior upon the increase of phonon frequency, followed by re-entrance into the quasi-ballistic regime, the heat conductance of a wire acquires an intermediate tendency to saturate within the temperature range $T\sim \hbar \omega_{1}/k_{B}$.Comment: 4 pages, 3 figures included; minor changes and corrections, figures 1 and 2 replaced by better versions; to appear in PRB Brief Report