153 research outputs found

    Antioxidant system of ginseng under stress by cadmium

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    Toxic levels of Cd can cause protein denaturation and oxidative stress, which result in membrane damage, enzimatic activity changes and other metabolic damage. Some plants may show alteration in the activity of their antioxidant enzymes as a heavy metal tolerance mechanism. This study aims at evaluating the role of enzymes of the antioxidant system in adaptive responses of the accumulator P. glomerata species to levels of cadmium (Cd). Plants were cultivated in nutrient solutions containing concentrations of Cd in the form of CdSO4 (0, 45 and 90 µmol L-1), for 20 d. Cd concentrations and yields of root and shoot dry matter were determined at the end of the experiment. Malondialdehyde (MDA) production and the activities of antioxidant enzymes were determined after days 1, 12 and 20. Higher Cd concentrations in tissues of P. glomerata were found to reduce biomass production in both roots and shoots. The lipid peroxidation rates in leaves and roots were smaller at the start of the experiment for all Cd levels. Superoxide dismutase (SOD) activity increased in leaves on day 1 and in roots on day 20 as Cd levels increased. Cd stress induced an increase in the activity of APX in leaves, whereas in roots ascorbate peroxidase (APX) activity was reduced at high concentration of Cd. At the end of the experiment, catalase (CAT) activity in leaves was reduced as Cd concentration increased. Nevertheless, the glutathione reductase (GR) and guaiacol peroxidase (GPX) activities increased. In roots, GR activity was reduced on days 1 and 20

    Influence of the Cobalt Phase on the Highly Efficient Growth of MWNTs

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    In this work, the influence of the cobalt phase on the growth of carbon nanotubes by the catalytic chemical vapour deposition of CH4 with catalysts containing Co, Mo and Mg is investigated. To this end, the catalytic behaviour of physically mixed CoO/MgO+MgMoO4 and CoMoO4+MgMoO4 is studied. The results obtained show that CoMoO4+MgMoO4 allows for the attainment of the highest CNT yield (2407 wt % against 1296 wt %). Its higher activity is ascribed to the greater formation of active sites that, in light of current assessments, are constituted by metallic cobalt adjacent to Mo2C, and the huge exfoliation of the catalyst, which contributes towards enhancing their exposure

    In vitro effects of simulated microgravity on Sertoli cell function

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    With the advent of space flights questions concerning the effects of microgravity (0G) on human reproductive physiology have received great attention. The aim of this study was to evaluate the influence of 0G on Sertoli cells. A Sertoli cell line from mouse testis (42GPA9) was analyzed for cytoskeletal and Sex Hormone Binding Globilin (SHBG) changes by immunohistochemistry, for antioxidant content by RT-PCR and for culture medium lactate concentrations by protein chemistry. Cells were cultured for 6, 24 and 48 h on a three-dimensional Random Positioning Machine (3D-RPM); static controls (1G) were positioned on the supporting frame. At the end of each experiment, cultured cells were either fixed in paraformaldehyde or lysed and RNA-extracted or used for culture medium lactate measurements as needed. At 0G, Sertoli cytoskeleton became disorganized, microtubules fragmented and SHBG undetectable already after 24 h, with alterations worsening by 48 h. It was evident that various antioxidant systems appreciably increased during the first 24 h but significantly decreased at 48 h. No changes occurred in the 1G samples. Initially, 0G seemed to disturb antioxidant pro- tection strategies allowing the testes to support sperm production, thus generating an aging-like state of oxidative stress. Lactate pro- duction at 0G slightly decreased after 24 h. Further experiments are needed in space to investigate upon steroidogenesis and germ cell differentiation within the testis, to rule out male infertility as a possible consequence, which could be a problem, as life expectancy increases.With the advent of space flights questions concerning the effects of microgravity (0G) on human reproductive physiology have 13 received great attention. The aim of this study was to evaluate the influence of 0G on Sertoli cells. A Sertoli cell line from mouse testis 14 (42GPA9) was analyzed for cytoskeletal and Sex Hormone Binding Globilin (SHBG) changes by immunohistochemistry, for antioxidant 15 content by RT-PCR and for culture medium lactate concentrations by protein chemistry. Cells were cultured for 6, 24 and 48 h on a 16 three-dimensional Random Positioning Machine (3D-RPM); static controls (1G) were positioned on the supporting frame. At the 17 end of each experiment, cultured cells were either fixed in paraformaldehyde or lysed and RNA-extracted or used for culture medium 18 lactate measurements as needed. At 0G, Sertoli cytoskeleton became disorganized, microtubules fragmented and SHBG undetectable 19 already after 24 h, with alterations worsening by 48 h. It was evident that various antioxidant systems appreciably increased during the 20 first 24 h but significantly decreased at 48 h. No changes occurred in the 1G samples. Initially, 0G seemed to disturb antioxidant pro- 21 tection strategies allowing the testes to support sperm production, thus generating an aging-like state of oxidative stress. Lactate pro- 22 duction at 0G slightly decreased after 24 h. Further experiments are needed in space to investigate upon steroidogenesis and germ 23 cell differentiation within the testis, to rule out male infertility as a possible consequence, which could be a problem, as life expectancy 24 increase

    CsPbBr3 Nanocrystals-Based Polymer Nanocomposite Films: Effect of Polymer on Spectroscopic Properties and Moisture Tolerance

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    Metal halide perovskites nanocrystals (NCs) represent an emerging class of materials that find increasing application in optoelectronic and photovoltaic devices, thanks to their intriguing optical properties, including high absorption coefficient, high fluorescence quantum yield (PL QY) and fast charge carrier separation. However, their opening to market is still hindered by their limited reliability, due to an intrinsic structural instability and degradation of their photophysical properties upon air, moisture, and light exposure. The incorporation of perovskite NCs in polymer matrix can limit some of the NC instability issues, with advantages in film processability, device fabrication and mechanical performance, being also useful for fundamental studies. In this regard, here, nanocomposites based on polymethylmethacrylate or polystyrene embedding all-inorganic CsPbBr3 NCs have been prepared and processed in the form of flexible free-standing films. A systematic spectrofluorimetric study, comprising steady state photoluminescence (PL), PL quantum yield (QY) and PL decay of the free-standing films before and after exposure to relative humidity condition (RH% 85%, at 25 °C) is performed and discussed. Phase segregation phenomena, changes in NC passivation and recombination dynamics are evaluated as a function of polymer loading and its molecular structure and finally the efficacy of the polymer as moisture barrier investigate

    Bilateral benign multinodular goiter: what is the adequate surgical therapy? A review of literature

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    Benign multinodular goiter (BMNG) is the most common endocrine disease requiring surgery. During the last few years a more aggressive approach has become the trend for bilateral BMNG treatment

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    Effects of deep heating modalities on the morphological and elastic properties of the non-insertional region of achilles tendon: a pilot study

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    Background: Over the last 20 years, both diathermy and ultrasound have been popular choices for many clinicians in treating musculoskeletal disorders. However, there is a lack of clinical evidence of deep heating modalities to treat tendon pathology, There is no study to investigate the effects of such as physical modalities on morphological and elastic properties on the human tendons. Objective: the objective of the present study was to compare the effects of diathermy and ultrasound therapies on cross sectional area, transversal height and hardness percentage of the non-insertional region of the Achilles tendon in able-bodied subjects. Methods: healthy volunteers were divided in diathermy and ultrasound group received six 15-min treatment sessions. Before and after treatment a sonographic assessment was conducted by mean of ultrasonography and the following parameters were recorded: cross sectional area, transversal height and hardness percentage. Results: thirty-two subjects were enrolled. Between-group comparisons showed a significant change on hardness percentage (p = 0.004) after treatment in diathermy therapy group. Within-group comparison showed a significant improvement in the hardness percentage for the diathermy (p = 0.001) and ultrasound (p = 0.046) after two weeks of treatment. Conclusion: this pilot study demonstrated larger effects on morphological and elastic properties of the non-insertional region of the Achilles tendon after diathermy than ultrasound therapy in normal tendons. Diathermy may be a useful deep heat modality for treating non-insertional Achilles tendinopathy

    Assessment of chicken breast shelf life based on bench-top and portable near-infrared spectroscopy tools coupled with chemometrics

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    Abstract Objectives Near-infrared (NIR) spectroscopy is a rapid technique able to assess meat quality even if its capability to determine the shelf life of chicken fresh cuts is still debated, especially for portable devices. The aim of the study was to compare bench-top and portable NIR instruments in discriminating between four chicken breast refrigeration times (RT), coupled with multivariate classifier models. Materials and Methods Ninety-six samples were analysed by both NIR tools at 2, 6, 10 and 14 days post mortem. NIR data were subsequently submitted to partial least squares discriminant analysis (PLS-DA) and canonical discriminant analysis (CDA). The latter was preceded by double feature selection based on Boruta and Stepwise procedures. Results PLS-DA sorted moderate separation of RT theses, while shelf life assessment was more accurate on application of Stepwise-CDA. Bench-top tool had better performance than portable one, probably because it captured more informative spectral data as shown by the variable importance in projection (VIP) and restricted pool of Stepwise-CDA predictive scores (SPS). Conclusions NIR tools coupled with a multivariate model provide deep insight into the physicochemical processes occurring during storage. Spectroscopy showed reliable effectiveness to recognise a 7-day shelf life threshold of breasts, suitable for routine at-line application for screening of meat quality

    Alimentação, uma das chaves para a saúde: Análise de Conteúdo de reportagens da revista Veja

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    Mediante a anlise de 09 reportagens da revista Veja, veiculadas no perodo de janeiro a dezembro de 2006, este estudo teve como objetivo analisar o contedo das reportagens publicadas sobre o tema da alimentao. As matrias que mais focaram a sade abordaram a alimentao como promotora da sade, como fator de risco no processo de adoecer e a associada esttica. Para a anlise dos dados foi utilizada a tcnica de Anlise de Contedo, segundo Bardin, e as informaes coletadas das reportagens foram organizadas em quatro categorias temticas. Da anlise constata-se a necessidade de investir na promoo da sade, como forma de possvel controle sobre os fatores de riscos para o adoecimento, entre eles a alimentao, pois muitas enfermidades esto relacionadas no s ao excesso alimentar como tambm inadequao qualitativa da dieta que predispe s diversas doenas, independentemente do ganho excessivo de peso
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