The effects of long-term chaetomellic acid a administration on renal function and oxidative stress in a rat model of renal mass reduction

This study aimed to evaluate the effect of chronic treatment with chaetomellic acid A (CAA) on oxidative stress and renal function in amodel of renalmass reduction. Methods.MaleWistar ratswere subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after surgery, rats have been divided into four experimental groups: RMR: RMR rats without treatment (n = 14); RMR + CAA: RMR rats treated with CAA (n = 13); SO: SO rats without treatment (n = 13); and SO + CAA: SO rats treated with CAA (n = 13). CAA was intraperitoneally administered in a dose of 0.23 μg/Kg three times a week for six months. Results. RMR was accompanied by a significant reduction in catalase and glutathione reductase (GR) activity (p < 0.05) and a decrease in reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. CAAadministration significantly increased catalase andGR activity (p < 0.05) and increased GSH/GSSG ratio, but no significant difference between the treated and nontreated groups was found in this ratio.No significant differences were found between theRMRgroups in any of the parameters of renal function.However, CAA administration slightly improves some parameters of renal function. Conclusions. These data suggest that CAA could attenuate 5/6 RMR-induced oxidative stress.The authors would like to thank Jos´e Miguel Lopez- Novoa for valuable comments and suggestions. This work is supported by European Investment Funds by FEDER/ COMPETE/POCI, Operational Competitiveness and Internationalization Programme, under Project POCI-01-0145- FEDER-006958, and National Funds by FCT, Portuguese Foundation for Science and Technology, under Project UID/AGR/04033/2013, and by European Investment Funds by FEDER/COMPETE/POCI, Operational Competitiveness and Internationalization Programme, under Project POCI- 01-0145-FEDER-016728, and National Funds by FCT, Portuguese Foundation for Science and Technology, under Project PTDC/DTP-DES/6077/2014.info:eu-repo/semantics/publishedVersio

Chaetomellic acid A treatment improves oxidative stress in rats with renal mass reduction

Chaetomellic acid A (CA) is a potent and highly specific inhibitor of Ras farnesyl-protein transferase that has shown to decrease oxidative stress in rats with brain damage. Oxidative stress has been suggested to play an important role in the pathogenesis of chronic renal disease. Thus, the aim of this work was to evaluate the effect of chronic treatment with CA on oxidative stress in a model of renal mass reduction. Male Wistar rats were subjected to 5/6 nephrectomy (RMR) or sham-operated (SO). One week after surgery, rats have been placed in four experimental groups: RMR rats without treatment (n=12); RMR rats treated with CA (n=8); SO rats without treatment (n=13); SO rats treated with CA (n=13). CA was intraperitoneally administered in a dose of 0.23 μg/Kg three times a week for six months. To evaluate the effect of CA on renal redox potential, the status of oxidative stress in renal tissues was determined. RMR was accompanied by a significant reduction in catalase and glutathione reductase (GR) activity, and a decrease in reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio. CA administration significantly increased catalase and GR activity (p<0.05), and increased GSH/GSSG ratio, but no significant difference between the treated and no treated groups was found in this ratio. These data suggest that CA can attenuate 5/6 RMR-induced oxidative stress and therefore, contribute to prevention of progressive renal failure in chronic renal disease

Elastoplastic and fracture behaviour of semi-crystalline polymers under multiaxial stress states

The deformation behaviour and fracture mechanisms of high-density polyethylene (HDPE), polypropylene (PP) and polyamide 6 (PA 6) are investigated experimentally under different stress states and at different crosshead speeds of 1, 20 and 200 mm/min. Fracture surface morphologies were investigated in a series of specimens tested at 200 mm/min under combined tension/shear loading at three different loading angles (α&nbsp;= 0°, 30° and 90°) at room temperature (RT) and 50 °C. In addition, the effects of notch profile radii (stress triaxiality) on HDPE, PP and PA 6 fracture behaviour have been studied at RT, using flat and cylindrical notched specimens. Specimens’ geometries were carefully designed to achieve various loading conditions and allowing to explore initial stress triaxialities ranged from 0 in pure shear loading (α&nbsp;= 0°) to a maximum of 0.84 for flat notched specimens with radius of 5 mm. The yield load shows an explicit dependency on temperature and crosshead speed. The fracture surfaces analysed reveals damage mechanisms such as crazing, void and cavitation formation. Two or more mechanisms are predominant, which means that the stresses along fracture process are not uniform

Electron impact ionization of R-carvone: I. Mass spectra and appearance energies

The mass spectrum of R-carvone measured at 70 eV electron impact energy, in the mass region of 1-151 amu, is reported in this work. We observed in this spectrum 103 peaks associated with ionic fragmentation, 55 of them with abundances greater than 1%. The relative abundances, from this study, compare reasonably well with the corresponding values reported in the literature where such a comparison can be made. The R-carvone Ionization Energy (IE), as well as the ionic energy formation thresholds (Appearance Energy - AE) were experimentally determined for the 35 most intense cations registered in the mass spectrum, which provided values for 38 AEs and Wannier exponents (p) and the IE of this molecule. The values of the AEs and Wannier exponents produced in this work, to the best of our knowledge, are being presented for the first time to the scientific community, except for the masses of 135 amu and 150 amu. We also suggest some ionic fragmentation mechanisms and molecular structural ionic fragmentation mechanisms for R-carvone, based on the AE and p values found in this work. (C) 2020 Elsevier B.V. All rights reserved

Elastoplastic and fracture behaviour of semi-crystalline polymers under multiaxial stress states

The deformation behaviour and fracture mechanisms of highdensity polyethylene (HDPE), polypropylene (PP) and polyamide 6 (PA 6) are investigated experimentally under different stress states and at different crosshead speeds of 1, 20 and 200 mm/min. Fracture surface morphologies were investigated in a series of specimens tested at 200 mm/min under combined tension/shear loading at three different loading angles ( ? = 0, 30deg and 90deg) at room temperature (RT) and 50 �C. In addition, the effects of notch profile radii (stress triaxiality) on HDPE, PP and PA 6 fracture behaviour have been studied at RT, using flat and cylindrical notched specimens. Specimens� geometries were carefully designed to achieve various loading conditions and allowing to explore initial stress triaxialities ranged from 0 in pure shear loading ( ? = 0�) to a maximum of 0.84 for flat notched specimens with radius of 5 mm. The yield load shows an explicit dependency on temperature and crosshead speed. The fracture surfaces analysed reveals damage mechanisms such as crazing, void and cavitation formation. Two or more mechanisms are predominant, which means that the stresses along fracture process are not uniform

Practical activities in textbooks for the middle school in natural sciences

RESUMO: As atividades práticas (AP) são uma estratégia no ensino e apren dizagem das ciências. Neste estudo apresentam-se os resultados da avaliação de AP incluídas em 5 manuais escolares (ME) de Ciências Naturais do 8º ano, do sistema de ensino português. Para o subdomínio “Gestão sustentável dos recursos” formulou-se a questão-problema: Tendo em conta as orientações dos documentos curriculares oficiais (DCO), será que as AP nos ME estão associadas ao desenvolvimento da literacia científica no âmbito de uma Educação para a Sustentabilidade (ES)? Definiram-se os objetivos: conhecer a frequência das AP propostas, por objetivos e ME; identificar a distribuição das AP em função da tipologia; aferir se existe predominância de uma tipologia de AP; estabelecer uma relação entre as AP que prevalecem e os DCO. A análise dos resultados permitiu concluir que existe uma diversidade de AP, em número e tipologia, mas nem sempre estão de acordo com as propostas dos DCO.ABSTRACT: Practical activities (PA) are a privileged strategy in teaching and learning of sciences. This study presents the results obtained from the assessment of the PA in 5 Natural Sciences Textbooks (ST) of the 8th grade. For the sub-domain "Sustainable management of resources" was formulated the research-question: Taking into account the official curricular documents (OCD) guidelines, will the PA in the ST be associated with the development of scientific literacy in the scope of an Education for Sustainability (ES)? The main goals were: to know the frequency of the proposed PA, by objectives and ST; to identify the distribution of PA according to the typology; to verify if the predominance of a PA typology exists; to establish a relationship between the prevailing PA and the OCD. The analysis of the results revealed that there is a diversity of PA, in both number and typology, but they are not always in agreement with proposed in the OCD.info:eu-repo/semantics/publishedVersio

Newly identified nematodes from Mono Lake exhibit extreme arsenic resistance

Extremophiles have much to reveal about the biology of resilience, yet their study is limited by sampling and culturing difficulties [1, 2, 3]. The broad success and small size of nematodes make them advantageous for tackling these problems [4, 5, 6]. We investigated the arsenic-rich, alkaline, and hypersaline Mono Lake (CA, US) [7, 8, 9] for extremophile nematodes. Though Mono Lake has previously been described to contain only two animal species (brine shrimp and alkali flies) in its water and sediments [10], we report the discovery of eight nematode species from the lake, including microbe grazers, parasites, and predators. Thus, nematodes are the dominant animals of Mono Lake in species richness. Phylogenetic analysis suggests that the nematodes originated from multiple colonization events, which is striking, given the young history of extreme conditions at Mono Lake [7, 11]. One species, Auanema sp., is new, culturable, and survives 500 times the human lethal dose of arsenic. Comparisons to two non-extremophile sister species [12] reveal that arsenic resistance is a common feature of the genus and a preadaptive trait that likely allowed Auanema to inhabit Mono Lake. This preadaptation may be partly explained by a variant in the gene dbt-1 shared with some Caenorhabditis elegans natural populations and known to confer arsenic resistance [13]. Our findings expand Mono Lake’s ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance. The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles

CETSI: uma proposta para um novo paradigma de ensino superior

Se hace una propuesta de creación de un Curso de Especialización en Tecnologías y Sistemas de Información (CETSI) en el marco del proceso de Bolonia y el Espacio Europeo de Educación Superior en colaboración entre España y Portugal.The courses of technologic specialization play a important role in the new paradigm of education learning, that is desired to be more flexible and adjusted to the demands of highly selective professional environment. To fit the concept of formation throughout life, in the context of the reforms proposed in the scope of the declaration of Bologna that considers the construction of a uniform space of superior education, constitutes a challenge for the universities and polytechnics of Portugal and Spain. Following the sequence of the developed efforts in the scope of the project financed by the community program INTERRG III a team of work was composed by elements of Portuguese and Spanish superior education, having in account the conception and accomplishment of a curricular proposal for a postgraduate course in the scientific fields of technology and systems of information. From the experience acquired in the course of CETSI it was possible to equate the bedding that we idealized as to become a net of academic cooperation

Un enfoque de informática de gestión para los estudios de Ingeniería Informática en el marco de Bolonia

La convergencia universitaria hacia un Espacio Europeo de Educación Superior supone cambios importantes en el tejido universitario en todos los países firmantes de la declaración de Bolonia. Las titulaciones de Ingeniería Informática en España figuran entre las que, presumiblemente, primero van sufrir las transformaciones necesarias. Por ello se están desarrollando diferentes estudios y propuestas dentro de un marco que, a fecha de hoy (abril de 2004), resulta todavía muy difuso. En este artículo se va a presentar una de estas propuestas, la cual se ha llevado a cabo entre la Universidad de Salamanca (España) y la Escuela Superior de Tecnología y Gestión de Bragança (Portugal) para definir un currículo de informática orientado hacia la informática de gestión y que cumpliese las directrices del marco de Bolonia.Este trabajo ha sido parcialmente financiado por la Unión Europea en la convocatoria de proyectos INTERREG III A