Stress Ratio Effects on the fatigue Properties of Biaxially Loaded Tubular FRP-Specimens ��� Experimental Study

In this work tubular fiber reinforced specimens are tested for fatigue life. The specimens are biaxially loaded with tension and shear stresses, with a load angle �� of 30�� and 60�� and a load ratio of R=0,1. There are many factors that affect fatigue life of a fiber reinforced material and the main goal of this work is to study the effects of load ratio R by obtaining S-N curves and compare them to the previous works (1). All the other parameters, such as specimen production, fatigue loading frequency and temperature, will be the same as for the previous tests. For every specimen, stiffness, temperature of the specimen during testing, crack counting and final fracture mode are obtained. Prior to testing, a study if the literature regarding the load ratio effects on composites fatigue life and with that review estimate the initial stresses to be applied in testing. In previous works (1) similar specimens have only been tested for a load ratio of R=-1 and therefore the behaviour of this tubular specimens for a different load ratio is unknown. All the data acquired will be analysed and compared to the previous works, emphasizing the differences found and discussing the possible explanations for those differences. The crack counting software, developed at the institute, has shown useful before, however different adjustments to the software parameters lead to different cracks numbers for the same picture, and therefore a better methodology will be discussed to improve the crack counting results. After the specimen���s failure, all the data will be collected and stored and fibre volume content for every specimen is also determinate. The number of tests required to make the S-N curves are obtained according to the existent standards. Additionally are also identified some improvements to the testing machine setup and to the procedures for future testing.

Oxidative stress in pregnancy and fertility pathologies

Oxidative stress designates the state of imbalance between reactive oxygen species (ROS) production and antioxidant levels. In a healthy placenta, there is an increase in ROS production, due to formation of new tissues and inherent metabolism, but this is balanced by higher levels of antioxidants. However, this balance is lost in some situations, with a consequent increase in oxidative stress levels. Oxidative stress has been implicated in several placental disorders and pregnancy pathologies. The present review intends to summarize what is known about the relationship between oxidative stress and well-known pregnancy disorders.

L���IMPORTANCE DES OBJETS DANS LA ���MAISON DE PASSAGE���: ENTRE NOSTALGIE ET STRATEGIES D���AFFIRMATION IDENTITAIRE

Relat��rio de Est��gio do Mestrado em Migra����es, Inter-etnicidades e Transnacionalismo

Sentido de coer��ncia em pessoas com diabetes de tipo 2 : autocuidado e controlo metab��lico��

RESUMO - A diabetes mellitus �� considerada um flagelo �� escala mundial, n��o apenas por atingir milh��es de pessoas, mas tamb��m porque se tem verificado um aumento da sua preval��ncia e, consequente-mente, das suas complica����es cr��nicas, que se traduzem no aumento dos gastos em sa��de e, sobretudo, em sofrimento das pessoas com diabetes, seus familiares e comunidade. A preven����o das complica����es cr��nicas da diabetes reside, sobretudo, na adop����o de comporta-mentos saud��veis que, no dia-a-dia, se traduzem em compet��ncia no autocuidado. Assim, ser�� importante conhecer em que medida o sentido de coer��ncia ��� caracter��stica pessoal entendida como influenciadora das estrat��gias utilizadas face aos acontecimentos originadores de stress, com repercuss��es na sa��de mental, bem como na sa��de f��sica ��� pode determinar a escolha de comportamentos de sa��de e, por tal, possa considerar-se como um aspecto sobre o qual os pro-fissionais de sa��de poder��o investir em prole do seu fortalecimento e, consequentemente, garantir a facilita����o do processo de adop����o de comportamentos saud��veis. De acordo com o estudo transversal explorat��rio retrospectivo proposto ambiciona-se conhecer a rela����o entre o n��vel de sentido de coer��ncia e o n��vel de autocuidado e de controlo metab��lico, das pessoas com diabetes de tipo 2. Para tal investiga����o reconhece-se a pertin��ncia da aplica-����o da escala de avalia����o do sentido de coer��ncia ��� Question��rio Orienta����o para Viver (Nunes, 1999), da escala de avalia����o do autocuidado com a diabetes ��� Escala de Avalia����o das Activida-des de Autocuidado com a Diabetes (Bastos, Severo e Lopes, 2007) e do Formul��rio de Controlo Metab��lico na Diabetes (European Society of Cardiology e European Association for the Study of Diabetes cit. por Direc����o-Geral da Sa��de, 2007), numa amostra constitu��da por 391 pessoas com diabetes de tipo 2, seleccionadas por amostragem aleat��ria estratificada proporcional, de entre os utentes inscritos nas 33 institui����es de Cuidados de Sa��de Prim��rios, do distrito de Viana do Castelo --------------------------- ABSTRACT - Diabetes mellitus is considered a global scourge, not only for reaching millions of people, but also because there has been an increase in its prevalence and, consequently, its chronic complications, which translate into increased spending on health and especially in the suffering of people with diabetes, their families and community. The prevention of chronic complications of diabetes includes adoption healthy behaviors that on the day to day, translate into competence in self-care. Therefore it is important to know how far the sense of coherence ��� understood as influential personal characteristic of the strategies used by the events originators of stress, affecting the mental health and physical health ��� may determine the choice of health behaviors and, as such, can be considered as an aspect about which health pro-fessionals will invest in strengthening their offspring and thus ensure the facilitation of the process of adopting healthy behaviors. According to the proposed retrospective exploratory cross-sectional study aims to discover the relationship between the level of sense of coherence and level of self-care and metabolic control on people with type 2 diabetes. For this research recognizes the appropriateness of applying the rating scale of sense of coherence ��� Question��rio Orienta����o para Viver (Nunes, 1999), the rating scale of self-care in diabetes ��� Escala de Avalia����o das Actividades de Autocuidado com a Di-abetes (Bastos, Severo and Lopes, 2007) and the Formul��rio de Controlo Metab��lico na Diabetes (European Society of Cardiology and European Association for the Study of Diabetes cit. por Di-rec����o-Geral da Sa��de, 2007), a sample of 391 people with type 2 diabetes, selected by propor-tional stratified random sampling from among registered users in 33 institutions of Primary Health Care, on district of Viana do Castelo.

Heat stress adaptation in hyperthermophiles: bosynthesis of inositol-containing compatible solutes

Dissertation presented to obtain the Ph.D. degree in Biochemistry

Disposable immunosensor using a simple method for oriented antibody immobilization for label-free real-time detection of an oxidative stress biomarker implicated in cancer diseases

This work proposes a novel approach for a suitable orientation of antibodies (Ab) on an immunosensing platform, applied here to the determination of 8-hydroxy-2���-deoxyguanosine (8OHdG), a biomarker of oxidative stress that has been associated to chronic diseases, such as cancer. The anti-8OHdG was bound to an amine modified gold support through its Fc region after activation of its carboxylic functions. Non-oriented approaches of Ab binding to the platform were tested in parallel, in order to show that the presented methodology favored Ab/Ag affinity and immunodetection of the antigen. The immunosensor design was evaluated by quartz-crystal microbalance with dissipation, atomic force microscopy, electrochemical impedance spectroscopy (EIS) and square-wave voltammetry. EIS was also a suitable technique to follow the analytical behavior of the device against 8OHdG. The affinity binding between 8OHdG and the antibody immobilized in the gold modified platform increased the charge transfer resistance across the electrochemical set-up. The observed behavior was linear from 0.02 to 7.0 ng/mL of 8OHdG concentrations. The interference from glucose, urea and creatinine was found negligible. An attempt of application to synthetic samples was also successfully conducted. Overall, the presented approach enabled the production of suitably oriented Abs over a gold platform by means of a much simpler process than other oriented-Ab binding approaches described in the literature, as far as we know, and was successful in terms of analytical features and sample application.

A molecularly imprinted sensor for sensitive detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG) oxidative stress biomarker

6th Graduate Student Symposium on Molecular Imprinting

A biomimetic sensor for monitoring oxidative stress biomarker in point-of-care

1st ASPIC International Congress

Wandlungen des Herrscherbildes im politischen Denken des Spatmittelalters

pp. 311-328

Functional and molecular characterization of SR45, a plant-specific factor involved in sugar and stress signaling in Arabidopsis thaliana

Dissertation presented to obtain the Ph.D degree in Molecular Biology

Adverse Effect of Alcohol Drinking: The Role of Oxidative Stress

Atualmente, o ��lcool tem um papel importante na sa��de p��blica e surge como um dos principais problemas sociais no mundo, dado que �� a droga mais viciante aceite em encontros sociais. Provavelmente, por essa raz��o, os riscos do consumo abusivo do ��lcool s��o subestimados pelos jovens, mulheres gr��vidas e idosos. O ��lcool, quando ingerido em altas propor����es, pode afetar todos os ��rg��os e desencadear in��meras doen��as, tais como a doen��a card��aca coronariana, doen��a neurodegenerativa, as doen��as cr��nicas e c��ncer. O ��lcool afeta ainda o estado psicol��gico, induzindo a viol��ncia, o estado antissocial e situa����es de risco de comportamentos. Por estas raz��es, o ��lcool tornou-se um foco principal da investiga����o, avaliando os seus efeitos sobre o corpo humano. Nesta pesquisa, foram suscitadas amostras de sangue de um grupo de pacientes em tratamento psicol��gico e/ou farmac��utico que ser��o analisadas com quatro m��todos: Teste de Radicais Livres do Oxig��nio (FORT), Defesa contra Radicais Livres do Oxig��nio (FORD), cromatografia gasosa (GC) e cromatografia l��quida de alta press��o (HPLC). Ambos os m��todos FORT e FORD avaliam o stress oxidativo pela quantifica����o de radicais livres e a capacidade de antioxidantes em eliminar esses radicais livres, respetivamente. O stress oxidativo �� o efeito do excesso de consumo de ��lcool, que �� reduzido pela capacidade de a����o dos antioxidantes. A boa reprodutibilidade, precis��o e exatid��o de ambos os m��todos indicam que estes podem ser aplicados em r��pidos diagn��sticos. Para o m��todo FORT e considerando o in��cio do tratamento, os pacientes alco��licos apresentaram uma m��dia de 3,59��1.01mmol/LH2O2 e o grupo de controlo uma m��dia de 1,42��0.53mmol/LH2O2, o que mostra uma diferen��a significativa entre os dois grupos (P=0,0006). Para o m��todo FORD, pacientes alco��licos apresentam uma m��dia de 1,07��0.53mmol/LH2O2 e o grupo de controlo, uma m��dia de 2,81��0.46mmol/LH2O2, mostrando tamb��m uma m��dia significativa (P=0,0075). Ap��s 15 dias de tratamento observou-se que h�� uma diferen��a entre os dois grupos de pacientes alco��licos, mas n��o h�� nenhum melhoramento em rela����o ao grupo de pacientes em tratamento. No m��todo FORT os grupos mostram uma diferen��a significativa (P=0,0073), tendo os pacientes sem tratamento farmac��utico melhores resultados (2.37��0.44mmol/LH2O2) do que os pacientes com tratamento (3.72��1,04mmol/LH2O2). O oposto ocorre no m��todo FORD, os pacientes em tratamento farmac��utico presentam melhores resultados (1.16��0.65mmol/LH2O2) do que o outro grupo (0.75��0.22mmol/LH2O2), n��o sendo, no entanto, uma diferen��a significativa entre os dois grupos (P=0.16). Os resultados obtidos para a concentra����o de MDA pelo m��todo de HPLC mostraram que o grupo de controlo tem valores mais baixos do que os pacientes alco��licos, embora a diferen��a n��o seja muito significativa (P = 0,084), mas �� ainda elevada. Al��m disso, os dois grupos de pacientes n��o apresentaram uma diferen��a significativa entre os seus resultados no in��cio (P=0,77) e no fim (P=0,79) do tratamento. De acrescentar ainda que, os resultados da concentra����o de ��lcool no sangue determinados pelo m��todo de CG mostraram que s�� alguns pacientes sem tratamento consumiram ��lcool durante o per��odo de tratamento, o que influencia negativamente a conclus��o sobre o efeito do tratamento. Contudo, outros fatores externos podem ainda influenciar os resultados finais, tais como o estado nutricional e estado psicol��gico dos pacientes, se o paciente continua a beber durante o tempo de tratamento ou at�� mesmo se o paciente �� exposto a outros tipos de subst��ncias nocivas. Existe ainda a possibilidade de o tempo de aplica����o do tratamento n��o ser suficiente para apresentar um efeito positivo em rela����o ao stress oxidativo e este �� um outro fator que contribui para a impossibilidade de confirmar sobre o efeito, quer seja positivo ou negativo, do tratamento antioxidante.

Sertraline accumulation and effects in the estuarine decapod Carcinusmaenas: Importance of the history of exposure to chemical stress

Sertraline is widely prescribed worldwide and frequently detected in aquatic systems. There is, however, a remarkable gap of information on its potential impact on estuarine and coastal invertebrates. This study investigated sertraline accumulation and effects in Carcinus maenas. Crabs from a moderately contaminated (Lima) and a low-impacted (Minho) estuary were exposed to environmental and high levels of sertraline (0.05, 5, 500 ��g L���1). A battery of biomarkers related to sertraline mode of action was employed to assess neurotransmission, energy metabolism, biotransformation and oxidative stress pathways. After a seven-day exposure, sertraline accumulation in crabs��� soft tissues was found in Lima (5 ��g L���1: 15.3 ng L���1 ww; 500 ��g L���1: 1010 ng L���1 ww) and Minho (500 ��g L���1: 605 ng L���1 ww) animals. Lima crabs were also more sensitive to sertraline than those from Minho, exhibiting decreased acetylcholinesterase activity, indicative of ventilatory and locomotory dysfunction, inhibition of anti-oxidant enzymes and increased oxidative damage at ���0.05 ��g L���1. The Integrated Biomarker Response (IBR) index indicated their low health status. In addition, Minho crabs showed non-monotonic responses of acetylcholinesterase suggestive of hormesis. The results pointed an influence of the exposure history on differential sensitivity to sertraline and the need to perform evaluations with site-specific ecological receptors to increase relevance of risk estimations when extrapolating from laboratory to field conditions.

Role of oxidative stress-induced systemic and cavernosal molecular alterations in the progression of diabetic erectile dysfunction

Background Erectile dysfunction (ED) is a prevalent complication of diabetes, and oxidative stress is an important feature of diabetic ED. Oxidative stress-induced damage plays a pivotal role in the development of tissue alterations. However, the deleterious effects of oxidative stress in the corpus cavernosum with the progression of diabetes remain unclear. The aim of this study was to evaluate systemic and penile oxidative stress status in the early and late stages of diabetes. Methods Male Wistar streptozotocin-diabetic rats (and age-matched controls) were examined 2 (early) and 8 weeks (late) after the induction of diabetes. Systemic oxidative stress was evaluated by urinary H2O2 and the ratio of circulating reduced/oxidized glutathione (GSH/GSSG). Penile oxidative status was assessed by H2O2 production and 3-nitrotyrosine (3-NT) formation. Cavernosal endothelial nitric oxide synthase (eNOS) was analyzed by quantitative immunohistochemistry. Dual immunofluorescence was also performed for 3-NT and ��-smooth muscle actin (��-SMA) and eNOS�����-SMA. Results There was a significant increase in urinary H2O2 levels in both diabetic groups. The plasma GSH/GSSG ratio was significantly augmented in late diabetes. In cavernosal tissue, H2O2 production was significantly increased in late diabetes. Reactivity for 3-NT was located predominantly in cavernosal smooth muscle (SM) and was significantly reduced in late diabetes. Quantitative immunohistochemistry revealed a significant decrease in eNOS levels in cavernosal SM and endothelium in late diabetes. Conclusions The findings indicate that the noxious effects of oxidative stress are more prominent in late diabetes. Increased penile protein oxidative modifications and decreased eNOS expression may be responsible for structural and/or functional deregulation, contributing to the progression of diabetes-associated ED.