1000 resultados para Isótopos de oxigênio


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O envelhecimento pode estar associado ao maior acúmulo de lesões celulares decorrentes das espécies reativas do oxigênio e do nitrogênio derivadas do metabolismo mitocondrial. Com a progressão da idade, há acúmulo de proteínas, lipídeos, carboidratos e DNA oxidados em relação a organismos jovens, de acordo com a teoria dos radicais livres. Entretanto, nem sempre os idosos ou animais envelhecidos apresentam maior estresse oxidativo que os jovens. Este artigo discute o paradoxo da teoria dos radicais livres de acordo com a teoria da biogênese da manutenção adequada do metabolismo mitocondrial. Diversos fatores podem contribuir para a redução do estresse oxidativo, como a hormese induzida pela prática regular de exercícios físicos, a restrição calórica, a ingestão de antioxidantes nutricionais e o aumento da produção de antioxidantes celulares que. em conjunto, estes promovem a expressão das sirtuínas e das proteínas do choque térmico, protegendo a integridade e funcionalidade mitocondriais, reduzindo o estresse oxidativo e nitrosativo, o que está associado à redução do envelhecimento e aumento da longevidade.

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O lactofen é um herbicida difeniléter recomendado para controlar plantas daninhas de folhas largas em campos de soja (Glycine max) e seu mecanismo de ação é a inibição da protoporfirinogênio-IX oxidase (Protox), que atua na biossíntese de clorofilas. Essa inibição resulta em um acúmulo de protoporfirina-IX, o que leva à produção de espécies reativas de oxigênio (ROS), causando estresse oxidativo. Conseqüentemente, podem ocorrer manchas, enrugamento e queima das folhas, o que leva à paralisação temporária do crescimento da cultura. Porém, o óxido nítrico (NO) atua como um antioxidante na eliminação direta das ROS. Assim, o objetivo deste trabalho foi verificar, por meio de avaliações fitométricas e bioquímicas, o efeito protetor do NO em plantas de soja tratadas com o herbicida lactofen. Plantas de soja foram pré-tratadas com diferentes doses de Nitroprussiato de Sódio (SNP), substância doadora de NO, e então pulverizadas com 168 g a.i. ha-1 lactofen. O pré-tratamento com SNP foi benéfico, pois o NO reduziu os sintomas de injúria causados pelo lactofen nos folíolos jovens e manteve baixos teores de açúcares solúveis. Porém, o NO proporcionou crescimento mais lento das plantas. Desta forma, posteriores estudos são necessários para elucidar os mecanismos de ação do NO na sinalização do estresse promovido pelo lactofen na cultura da soja.

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In the present work we use a plasma jet system with a hollow cathode to deposit thin TiO2 films on silicon substrates as alternative at sol-gel, PECVD, dip-coating e magnetron sputtering techniques. The cylindrical cathode, made from pure titanium, can be negatively polarized between 0 e 1200 V and supports an electrical current of up to 1 A. An Ar/O2 mixture, with a total flux of 20 sccm and an O2 percentage ranging between 0 and 30%, is passed through a cylindrical hole machined in the cathode. The plasma parameters and your influence on the properties of deposited TiO2 films and their deposition rate was studied. When discharge occurs, titanium atoms are sputtered/evaporated. They are transported by the jet and deposited on the Si substrates located on the substrate holder facing the plasma jet system at a distance ranging between10 and 50 mm from the cathode. The working pressure was 10-3 mbar and the deposition time was 10 -60 min. Deposited films were characterized by scanning electron microscopy and atomic force microscopy to check the film uniformity and morphology and by X-ray diffraction to analyze qualitatively the phases present. Also it is presented the new dispositive denominate ionizing cage, derived from the active screen plasma nitriding (ASPN), but based in hollow cathode effect, recently developed. In this process, the sample was involved in a cage, in which the cathodic potential was applied. The samples were placed on an insulator substrate holder, remaining in a floating potential, and then it was treated in reactive plasma in hollow cathode regime. Moreover, the edge effect was completely eliminated, since the plasma was formed on the cage and not directly onto the samples and uniformity layer was getting in all sampl

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Lithium (Li) is a chemical element with atomic number 3 and it is among the lightest known elements in the universe. In general, the Lithium is found in the nature under the form of two stable isotopes, the 6Li and 7Li. This last one is the most dominant and responds for about 93% of the Li found in the Universe. Due to its fragileness this element is largely used in the astrophysics, especially in what refers to the understanding of the physical process that has occurred since the Big Bang going through the evolution of the galaxies and stars. In the primordial nucleosynthesis in the Big Bang moment (BBN), the theoretical calculation forecasts a Li production along with all the light elements such as Deuterium and Beryllium. To the Li the BNB theory reviews a primordial abundance of Log log ǫ(Li) =2.72 dex in a logarithmic scale related to the H. The abundance of Li found on the poor metal stars, or pop II stars type, is called as being the abundance of Li primordial and is the measure as being log ǫ(Li) =2.27 dex. In the ISM (Interstellar medium), that reflects the current value, the abundance of Lithium is log ǫ(Li) = 3.2 dex. This value has great importance for our comprehension on the chemical evolution of the galaxy. The process responsible for the increasing of the primordial value present in the Li is not clearly understood until nowadays. In fact there is a real contribution of Li from the giant stars of little mass and this contribution needs to be well streamed if we want to understand our galaxy. The main objection in this logical sequence is the appearing of some giant stars with little mass of G and K spectral types which atmosphere is highly enriched with Li. Such elevated values are exactly the opposite of what could happen with the typical abundance of giant low mass stars, where convective envelops pass through a mass deepening in which all the Li should be diluted and present abundances around log ǫ(Li) ∼1.4 dex following the model of stellar evolution. In the Literature three suggestions are found that try to reconcile the values of the abundance of Li theoretical and observed in these rich in Li giants, but any of them bring conclusive answers. In the present work, we propose a qualitative study of the evolutionary state of the rich in Li stars in the literature along with the recent discovery of the first star rich in Li observed by the Kepler Satellite. The main objective of this work is to promote a solid discussion about the evolutionary state based on the characteristic obtained from the seismic analysis of the object observed by Kepler. We used evolutionary traces and simulation done with the population synthesis code TRILEGAL intending to evaluate as precisely as possible the evolutionary state of the internal structure of these groups of stars. The results indicate a very short characteristic time when compared to the evolutionary scale related to the enrichment of these stars

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Introduction: The ability to walk is impaired in obese by anthropometric factors (BMI and height), musculoskeletal pain and level of inactivity. Little is known about the influence of body adiposity and the acute response of the cardiovascular system during whole the 6-minute walk test (6mWT). Objective: To evaluate the effect of anthropometric measures (BMI and WHR waist-to-hip ratio), the effort heart and inactivity in ability to walk the morbidly obese. Materials and Methods: a total 36 morbidly obese (36.23 + 11.82 years old, BMI 49.16 kg/m2) were recruited from outpatient department of treatment of obesity and bariatric surgery in University Hospital Onofre Lopes and anthropometric measurements of obesity (BMI and WHR), pulmonary function, pattern habitual physical activity (Baecke Questionnaire) and walking capacity (6mWT). The patient was checking to measure: heart rate (HR), breathing frequency (BF), peripheral oxygen saturation, level of perceived exertion, systemic arterial pressure and duplo-produto (DP), moreover the average speed development and total distance walking. The data were analysed between gender and pattern of body adiposity, measuring the behavior minute by minute of walking. The Pearson and Spearmam correlation coefficients were calculated, and stepwise multiple Regression examined the predictors of walking capacity. All analyses were performed en software Statistic 6.0. Results: 20 obese patients had abdominal adiposity (WHR = 1.01), waist circumference was 135.8 cm in women (25) and 139.8 cm in men (10). Walked to the end of 6mWT 412.43 m, with no differences between gender and adiposity. The total distance walked by obesity alone was explained by BMI (45%), HR in the sixth minute (43%), the Baecke (24%) and fatigue (-23%). 88.6% of obese (31) performed the test above 60% of maximal HR, while the peak HR achieved at 5-minute of 6mWT. Systemic arterial pressure and DP rised after walking, but with no differences between gender and adiposity. Conclusion: The walk of obese didn´t suffers influence of gender or the pattern of body adiposity. The final distance walked is attributed to excess body weight, stress heart, the feeling of effort required by physical activity and level of sedentary to obese. With a minute of walking, the obeses achieved a range of intensity cardiovascular trainning

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Backgroud: Obesity is a major public health problem and is related to the low physical capacity when obese are compared to no-obese people, however the cause of this limitation is not completely understood. The measurement associated of physiological response to the telemetric 6MWT adds information of metabolic and respiratory system for diagnose of the functional limitation. Objective: Analyze physiological, metabolic and ventilatory responses in women with different body fat during the 6MWT. Methods: 32 women (8 non-obese, 8 Overweight, 8 Obese and 8 morbidly obese) were evaluated for anthropometry, lung function and exercise capacity. Results: Morbidly obese walked the shortest distance (400.2±38.7m), had lower VO2/Kg (12.75±3.20l/Kg/min) and lower R (0.74± 0.11) in the 6MWT compared to other groups. Analyses of metabolic (VO2 and VCO2) and respiratory (VE, VT and BF) during the test did not identify differences between groups. The evaluation of cardiac function (O2 pulse) found higher values in the OM (12.3 ± 4.9ml/bat). Conclusion: The OM had worse performance in the 6MWT compared to other groups. The physical performance may be reduced in this population related to a protocol-dependent response because the speed of 6MWT is self-adjusted allows the individual himself select the intensity of the test, making it set at a speed where there is energy saving

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Introduction: Pneumonia is an inflammatory lung disease and it is the greatest cause of deaths in children younger than five years of age worldwide. Chest physiotherapy is widely used in the treatment of pneumonia because it can help to eliminate inflammatory exudates and tracheobronchial secretions, remove airway obstructions, reduce airway resistance, enhance gas exchange and reduce the work of breathing. Thus, chest physiotherapy may contribute to patient recovery as an adjuvant treatment even though its indication remains controversial. Objectives: To assess the effectiveness of chest physiotherapy in relation to time until clinical resolution in children (from birth up to 18 years old) of either gender with any type of pneumonia. Methods: We searched CENTRAL 2013, Issue 4; MEDLINE (1946 to May week 4, 2013); EMBASE (1974 to May 2013); CINAHL (1981 to May 2013); LILACS (1982 to May 2013); Web of Science (1950 to May 2013); and PEDro (1950 to May 2013). We consulted the ClinicalTrials.gov and the WHO ICTRP registers to identify planned, ongoing and unpublished trials. We consulted the reference lists of relevant articles found by the electronic searches for additional studies. We included randomised controlled trials (RCTs) that compared chest physiotherapy of any type with no chest physiotherapy in children with pneumonia. Two review authors independently selected the studies to be included in the review, assessed trial quality and extracted data. Results: Three RCTs involving 255 inpatient children are included in the review. They addressed conventional chest physiotherapy, positive expiratory pressure and continuous positive airway pressure. The following outcomes were measured: duration of hospital stay, time to clinical resolution (observing the following parameters: fever, chest indrawing, nasal flaring, tachypnoea and peripheral oxygen saturation levels), change in adventitious sounds, change in chest X-ray and duration of cough in days. Two of the included studies found a significant improvement in respiratory rate and oxygen saturation whereas the other included study failed to show that standardised respiratory physiotherapy and positive expiratory pressure decrease the time to clinical resolution and the duration of hospital stay. No adverse effects related to the interventions were xvi described. Due to the different characteristics of the trials, such as the duration of treatment, levels of severity, types of pneumonia and the techniques used in children with pneumonia, as well as differences in their statistical presentation, we were not able to pool data. Two included studies had an overall low risk of bias whereas one included study had an overall unclear risk of bias. Conclusion: Our review does not provide conclusive evidence to justify the use of chest physiotherapy in children with pneumonia due to a lack of data. The number of included studies is small and they differed in their statistical presentation

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The term fatigability concerns the degree of fatigue associated with performing an activity of any type (physical, mental, emotional and / or social). Recently scales for assessing fatigue in the English language were created, however, gaps exist regarding the validity of these scales in relation to oxygen consumption and levels of perceived fatigue. Objective: To investigate the validity of perceived fatigability scale in older women frail and non-frail by the expired gases kinetics. Methods: This is a study of type validation, where were evaluated 48 elderly. The evaluation was conducted at two different sessions. In the first, data were collected demographic partners, as well as assessment of cognitive function, physical health, and the phenotype of frailty. The second was composed by the test 6-minute walk (6MWT) associated the expired gases kinects and assessment of perceived fatigability. Statistical analysis was performed a descriptive analysis and then we used the Pearson correlation test to evaluate the relationship between the measure of perceived fatigue and variables oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER)before and after 6MWT. We used a linear regression model initially considering the following explanatory variable: age, Body Mass Index (BMI), presence of frailty, comorbidities, level of physical activity, distance covered in the 6MWT , the energy cost of walking and severity of fatigability on performance. Results: The final sample consisted of 44 elderly women, 4 elderly were excluded because they didn t complete all phases of this study. The mean age obtained was 75 years (± 7.2 years). There was no significant correlation between fatigability measures and the values of VO2 ( r = .09 , p = .56 ) , VCO2 ( r = .173 , p = .26 ) , RER ( r = - .121 , p = .43 ). The final linear regression model showed that the energy cost of walking, the usual level of physical activity and the performance severity of fatigability explained 83.5 % (R2 = 0.835, p < 0.01) of the variation in the perceived fatigability. Conclusion: Our findings indicate a relationship between greater severity of fatigability and lower levels of physical activity and increased energy cost in walking, suggesting that the fatigability analyses using a simple numeric scale is valid and viable for assessment of fatigue in older women

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obesity affects rightly functional capacity diminishing the cardiovascular system efficiency and oxygen uptake (VO2). Field tests, such as, Incremental Shuttle Walking Test (ISWT) and Six Minute Walk Test (6MWT) has been employed as alternative of Cardiopulmonary Exercise Test (CPX), to functional assessing for conditions which transport of oxygen to peripheral is diminished. Nevertheless, the knowing about metabolic variables response in real time and it comparing among different maximal and submaximal tests in obese is absent. Aim: to compare cardiopulmonary, metabolic response during CPX, ISWT and 6MWT and to analyse it influence of adiposity markers in obese. Material e Method: crosssectional, prospective study. Obese included if: (BMI>30Kg/m2; FVC>80%), were assessed as clinical, anthropometric (BMI, body adiposity index-BAI, waist-WC, hip- HC and neck-NC circumferences) and spirometry (forced vital capacity-FVC, Forced expiratory volume-1°second-FEV1, maximal voluntary ventilation-MVV) variables. Obese performed the sequence of tests: CPX, ISWT and 6MWT. Throughout tests was assessed breath-by-breath by telemetry system (Cortex-Biophysik-Metamax3B) variables; oxygen uptake on peak of activity (VO2peak); carbon dioxide production (VCO2); Volume Expiratory (VE); ventilatory equivalents for VO2 (VE/VO2) and CO2 (VE/VCO2); respiratory exchange rate (RER) and perceived effort-Borg6-20). Results: 15 obese (10women) 39.4+10.1years, normal spirometry (%CVF=93.7+9.7) finished all test. They have BMI (43.5+6.6kg/m2) and different as %adiposity (BAI=50.0+10.5% and 48.8+16.9% respectively women and men). Difference of VO2ml/kg/min and %VO2 were finding between CPX (18.6+4.0) and 6MWT (13.2+2.5) but not between ISWT (15.4+2.9). Agreement was found for ISWT and CPX on VO2Peak (3.2ml/kg/min; 95%; IC-3.0 9.4) and %VO2 (16.4%). VCO2(l/min) confirms similarity in production for CPX (2.3+1.0) and ISWT (1.7+0.7) and difference for 6MWT (1.4+0.6). WC explains more the response of CPX and ISWT than other adiposity markers. Adiposity diminishes 3.2% duration of CPX. Conclusion: ISWT promotes similar metabolic and cardiovascular response than CPX in obese. It suggesting that ISWT could be useful and reliable to assess oxygen uptake and functional capacity in obese

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Bacterial meningitis (BM) is still an important infectious disease causing death and disability. Invasive bacterial infections of the central nervous systems (CNS) generate some of the most powerful inflammatory responses known, which contributes to neuronal damage. The DNA microarray technology showed alterations in the kynurenine (KYN) pathway that is induced in BM and other diseases associated with inflammation, leading to brain injury. Our main aim was to search SNPs previously described in the KYN path enzymes to investigate a putative association of this SNPs with imbalanced in this pathway in patients with BM. The patients included in this study were 33 males and 24 females, with ages varying from 02 months to 68 years. SNPs were located inside of the domain conserved in KYNU, IDO, KATI and KATII. Primers were designed for analysis of SNPs already described by PIRA-PCR followed by RFLP. The analysis of KYNU+715G/A SNP found a heterozygous frequency of 0.033. We did not found the variant allele of SNP KYNU+693G/A, KATI+164T/C, KATII+650C/T and IDO+434T/G. Despite of previews studies showing the importance of KYN pathway we did not found one association of these SNPs analyzed with susceptibility or severity of MB in study population.

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Despite advances in vaccine development and therapy, bacterial meningitis (BM) remains a major cause of death and long-term neurological disabilities. As part of the host inflammatory response to the invading pathogen, factors such as reactive oxygen species are generated, which may damage DNA and trigger the overactivation of DNA repair mechanisms. It is conceivable that the individual susceptibility and outcome of BM may be in part determined by non synonymous polymorphisms that may alter the function of crucial BER DNA repair enzymes as PARP-1, OGG-1 and APE-1. These enzymes, in addition to their important DNA repair function, also perform role of inflammatory regulators. In this work was investigated the non synonymous SNPs APE-1 Asn148Glu, OGG-1 Ser326Cys,PARP-1 Val762Ala, PARP-1 Pro882Leu and PARP-1 Cys908Tyr in patients with bacterial meningitis (BM), chronic meningitis (CM), aseptic meningitis (AM) and not infected (controls). As results we found increased frequency of variant alleles of PARP-1 Val762Ala (P = 0.005) and APE-1 Asn148Glu (P=0.018) in BM patients, APE-1 Asn148Glu in AM patients (P = 0.012) and decrease in the frequency of the variant allele OGG-1 Ser326Cys in patients with CM (P = 0.013), regarding the allelic frequencies in the controls. A major incidence of individuals heterozygous and/ or polymorphic homozygous in BM for PARP-1 Val762Ala (P= 0.0399, OD 4.2, 95% IC 1.213 -14.545) and PARP-1 Val762Ala/ APE-1 Asn148Glu (P = 0.0238, OD 11.111, 95% IC 1.274 - 96.914) was observed related to what was expected in a not infected population. It was also observed a major incidence of combined SNPs in the BM patients compared with the control group (P=0.0281), giving evidences that SNPs can cause some susceptibility to the disease. This combined effect of SNPs seems to regulate the principal cytokines and other factors related to BM inflammatory response and point the importance of DNA repair not only to repair activity when DNA is damaged, but to others essential functions to human organism balance.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Photodynamic therapy (PDT) has been proposed as an alternative method for the treatment of biofilm-dependent oral diseases like dental caries. This therapy consists of simultaneous action of a visible light (L) and a photosensitizer (FS) in the presence of oxygen, which leads to production of different reactive oxygen species that can interact with the bacterial cell components, and promote cell death. This study aims to evaluate the antimicrobial action of PDT on oral bacteria in suspension, as well as the formation of mono and multi-species biofilms, in vitro, from a standard strain of Streptococcus mutans (ATCC 25175) and saliva samples, respectively. The dye methylene blue (MB) and toluidine blue (TB) were used at a concentration of 100 mg/ L and activated by halogen light (600 to 750 nm) from a modified hand held photopolymerizer (Ultralux ®, Dabi Atlante, Ribeirão Preto , São Paulo, Brazil.). Planktonic cultures were prepared and submitted to different experimental conditions: 1. PDT using TB 2. PDT using MB, 3. L+ FS- , 4. TB + L - ; 5. MB+ L-; 6. L- FS- (negative control) and 7. administration of 0.12% chlorhexidine digluconate (positive control) (Periogard ®, Colgate-Palmolive Company, New York, USA). The immediate and mediated action of PDT on bacterial suspensions, as well as its effect on biofilm formation were observed from the number of colony-forming units per milliliter (CFU/mL) and measures optical density (OD). The data were statistically analyzed using the Kruskal-Wallis and Mann-Whitney test for the significance level of 5%. According to the results, the PDT showed no antibacterial action on suspensions of S. mutans, regardless of the dye used. PDT with MB activated by halogen light was able to reduce 86.6% CFU/mL multi-species planktonic cultures, however, this reduction was not significant (p > 0.05). PDT showed antibacterial effect, mediate on multi-species planktonic cultures with TB (p < 0.001) and MB (p < 0.001), activated by halogen light. PDT was able to prevent the formation of multispecies biofilm, through the activation of TB by halogen light (p = 0.01). We conclude that activation of the dye toluidine blue and methylene blue, by halogen light (PDT) showed antimicrobial activity, compared to multi-species planktonic cultures prepared from saliva samples