869 resultados para Light - Physiological effect
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This chapter reviews studies on the effects of mycotoxins on embryonic and fetal development, especially those toxins that are global food and feed contaminants. The toxins discussed include aflatoxin produced by Aspergillus flavus and A. parasiticus, ochratoxin which is produced by Aspergillus species particularly A. ochraceus as well as Penicillium verrucosum, ergot alkaloids produced by Claviceps spp., and the Fusarium toxins (fumonisins, deoxynivalenol [vomitoxin], and zearalenone). These toxins have been shown to be teratogenic and/or embryotoxic in different animal bioassays. The implications of toxicity on embryogenesis, and the progress of research on these mycotoxins, are also examined.
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Purpose: Autofluorescence of ultraviolet (UV) light has been shown to occur in localised areas of the bulbar conjunctiva, which map to active cellular changes due to UV and environmental exposure. This study examined the presence of conjunctival UV autofluorescence in eye care practitioners (ECPs) across Europe and the Middle East and its associated risk factors. Method: Images were captured of 307 ECPs right eyes in the Czech Republic, Germany, Greece, Kuwait, Netherlands, Sweden, Switzerland, United Arab Emirates and the United Kingdom using a Nikon D100 camera and dual flash units through UV filters. UV autofluorescence was outlined using ImageJ software and the nasal and temporal area quantified. Subjects were required to complete a questionnaire on their demographics and lifestyle including general exposure to UV and refractive correction. Results: Average age of the subjects was 38.5±12.2 years (range 19-68) and 39.7% were male. Sixty-two percent of eyes had some conjunctival damage as indicated by UV autofluorescence. The average area of damage was higher (p=0.005) nasally (2.95±4.52mm2) than temporally (2.19±4.17mm2). The area of UV damage was not related to age (r=0.03, p=0.674), gender (p=0.194), self-reported sun exposure lifestyle (p>0.05), geographical location (p=0174), sunglasses use (p>0.05) or UV-blocking contact lens use (p>0.05), although it was higher in those wearing contact lenses with minimal UV-blocking and no spectacles (p=0.015). The area of UV damage was also less nasally in those who wore contact lenses and spectacles compared to those with no refractive correction use (p=0.011 nasal; p=0.958 temporal). Conclusion: UV conjunctival damage is common even in Europe, Kuwait and UAE, and among ECPs. The area of damage appears to be linked with the use of refractive correction, with greater damage nasally than temporally which may be explained by the peripheral light focusing effect.
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This study attempted to determine if an excessive amount of 1,1,1 - Trichloroethane was released into the air, the acute effects of exposure and the cause(s) of excessive use. The types of degreasing equipments which were tested in this study are straight vapor and the vapor spray machines. The instruments utilized to obtain the data for this study are Gastech Haline Detector, Organic Vapor Monitor Badge and Personal Sampling Pump. Readings were taken on three different tanks. The data accumulated by this study were obtained during actual cleaning operation. During testing, increased exposure was detected due to exceeding the rate of removal, downward drafts were blowing right over the top of a degreaser and, in some cases, poor general ventilation caused solvent vapor to be blown out of the tank and into the workers' breathing zone, affecting excessive vapor drag out and solvent loss. The results show that, since the characteristics of solvent 1,1,1 - Trichloroethane are well suited to vapor degreasing requirements, by using proper procedures and maintenance, 1,1,1 - Trichloroethane emission during vapor degreasing can be controlled at levels well below the industrial hygiene standard established by OSHA for safe and healthful conditions.
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The peaches and nectarines are highly appreciated by consumer, but it is climacteric fruits, with availability in the market in small time. It is necessary to invest to obtain genotypes with fruit quality and small perishability or that it presente less physiological disorders after storage. The aims of this work were i) to evaluate the genetic divergence among 40 peach and nectarine trees genotypes based on postharvest quality and select posible parents; ii) to evaluate the susceptibility to chilling injury in peaches and nectarines after cold storage; iii) to evaluate divergence of peaches and nectarines on the basis in the susceptibility for chiling injury and select superior genotypes; iv) evaluate the correlations between quality and susceptibility to chilling injury of peaches and nectarines v) select parents with the combination of lower susceptibility to chilling injury and higher quality fruit. The study was carried out in EEAD-CSIC, Zaragoza - Spain, during the production cycle 2013/2014. A total of 40 peaches and nectarines genotypes from germplasm collection were evaluated. The quality characteristics as flesh firmness, total soluble solids, titratable acidity, pH, rippining index and flesh color parameters were evaluated. The fruits were submitted to cold storage at 0 °C and 5 °C, with 95% average relative humidity. The evaluations were after 14 and 28 days, it being observed the presence of symptoms, such as wooliness through mealiness, flesh grainy, leatheriness and flesh color changes, through browning, bleeding and off flavor. As a selection parameter was adopted 20% of genotypes that had a higher frequency of superiority for quality characteristics, susceptibility to chilling injury and the combining of both. For quality characteristic presented greater divergence the ‘Queen Giant’, ‘Sudanel Blanco’ and ‘Borracho de Jarque’. Based on the quality the eight genotypes were selected, ‘Andross’, ‘San Jaime’, ‘San Lorenzo’, ‘Borracho de Jarque’, ‘Sudanell 1’, ‘Carson’, ‘Baby Gold 6’ and ‘Stanford’. All genotypes studied exhibited susceptibility to one or more symptoms caused by cold storage during 28 days, independent of temperature. For 14 days, the ‘Baby Gold 6’, ‘Flavortop’ and ‘Queen Giant’ genotypes did not show any physiological disorder caused by cold. In general, the temperature of 0 °C favored fruit postharvest conservation, it have a lower incidence and severity of symptoms caused by cold storage. The storage for 14 days contributed for the lower incidence of damage in the genotypes fruits studied. For 14 days, with both temperatures, it was observed divergence for ‘Queen Giant’, ‘Sudanell Blanco’, ‘Baby Gold 6’ ‘GF3’, ‘Baby Gold 8’, ‘Campiel’ and ‘Campiel Rojo’ genotypes. For 28 days, in the 5 °C condition, ‘Queen Giant’, ‘Big Top’, ‘Flavortop’ and ‘Redhaven’ genotypes were divergents. Based on susceptibility to chilling injury at 0 °C, the eight genotypes were selected, it being these, ‘Queen Giant’, ‘Keimoes’, ‘Flavortop’, ‘Big Top’, 'Redhaven', 'Sudanell 3', 'Bonet I' and ‘Carson’. The quality parameters as rippining index, soluble solids, firmness and titratable acidity presented correlation among them. These, also it had correlation with woolines and bowning, what it indicate that fruits with more ripening can have this symptoms more easily. The browning, mealiness, flesh grainy and off flavor variables were correlationed with the time period and temperartures, what it confirm that these symptoms are the main disorders caused by cold storage. The quality characteristics together susceptibility to chilling injury allowed selected ‘Baby Gold 6’, ‘Sarell’, ‘Keimoes’, ‘GF3’ ‘San Jaime’, ‘Big Top’, ‘Sudanell 1’, ‘Carson’, ‘Baby Gold 8’, and ‘San Lorenzo’ genotypes.
Quantificação de açúcares com uma língua eletrónica: calibração multivariada com seleção de sensores
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Este trabalho incide na análise dos açúcares majoritários nos alimentos (glucose, frutose e sacarose) com uma língua eletrónica potenciométrica através de calibração multivariada com seleção de sensores. A análise destes compostos permite contribuir para a avaliação do impacto dos açúcares na saúde e seu efeito fisiológico, além de permitir relacionar atributos sensoriais e atuar no controlo de qualidade e autenticidade dos alimentos. Embora existam diversas metodologias analíticas usadas rotineiramente na identificação e quantificação dos açúcares nos alimentos, em geral, estes métodos apresentam diversas desvantagens, tais como lentidão das análises, consumo elevado de reagentes químicos e necessidade de pré-tratamentos destrutivos das amostras. Por isso se decidiu aplicar uma língua eletrónica potenciométrica, construída com sensores poliméricos selecionados considerando as sensibilidades aos açucares obtidas em trabalhos anteriores, na análise dos açúcares nos alimentos, visando estabelecer uma metodologia analítica e procedimentos matemáticos para quantificação destes compostos. Para este propósito foram realizadas análises em soluções padrão de misturas ternárias dos açúcares em diferentes níveis de concentração e em soluções de dissoluções de amostras de mel, que foram previamente analisadas em HPLC para se determinar as concentrações de referência dos açúcares. Foi então feita uma análise exploratória dos dados visando-se remover sensores ou observações discordantes através da realização de uma análise de componentes principais. Em seguida, foram construídos modelos de regressão linear múltipla com seleção de variáveis usando o algoritmo stepwise e foi verificado que embora fosse possível estabelecer uma boa relação entre as respostas dos sensores e as concentrações dos açúcares, os modelos não apresentavam desempenho de previsão satisfatório em dados de grupo de teste. Dessa forma, visando contornar este problema, novas abordagens foram testadas através da construção e otimização dos parâmetros de um algoritmo genético para seleção de variáveis que pudesse ser aplicado às diversas ferramentas de regressão, entre elas a regressão pelo método dos mínimos quadrados parciais. Foram obtidos bons resultados de previsão para os modelos obtidos com o método dos mínimos quadrados parciais aliado ao algoritmo genético, tanto para as soluções padrão quanto para as soluções de mel, com R²ajustado acima de 0,99 e RMSE inferior a 0,5 obtidos da relação linear entre os valores previstos e experimentais usando dados dos grupos de teste. O sistema de multi-sensores construído se mostrou uma ferramenta adequada para a análise dos iii açúcares, quando presentes em concentrações maioritárias, e alternativa a métodos instrumentais de referência, como o HPLC, por reduzir o tempo da análise e o valor monetário da análise, bem como, ter um preparo mínimo das amostras e eliminar produtos finais poluentes.
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There are reports that strobilurin besides having a fungicide effect can promote physiologic benefits to the plants. However, this effect on banana plants was not studied yet. The objective of the present study was to evaluate the effect of strobirulins on the physiology of banana plantlets. For this purpose, cultivar Grand Naine banana plantlets were transferred to pots containing substrate and kept in a nursery with 50% shading. The experimental design was a completely randomized design with three treatments (water, azoxystrobin and pyraclostrobin) and five replications. The treatments were applied at 15, 30, 45, 60 and 75 days after transplanting at a dose 100 g a. i. ha(-1) with manual spray. Plant height, pseudostem diameter, shoot dry matter in strobilurin treated plants were higher than the untreated plants, however, the effect of fungicide treatment was different, being the most pronounced effect of pyraclostrobin compared to azoxystrobin. Plants treated with pyraclostrobin had higher leaf area, nitrate reductase activity and chlorophyll content of leaf total nitrogen than the plants treated with azoxystrobin and water, which did not differ. Strobilurins affect the physiology of the banana plantlets differently, the effect being more pronounced by pyraclostrobin.
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Several researchers have investigated the effects of alcohol on memory. Few researchers have studied the effects of alcohol on an eyewitness's recall and recognition of crime events. This study proposed to examine the effects of alcohol and viewing conditions on subjects' ability to recall information regarding a videotaped bank robbery. Thirty male and 22 female subjects participated in a 2 (consumption: alcohol v. no alcohol) x 2 (lighting: good v. poor) factorial experiment with Average Accuracy and Total Amount of Information recalled as the primary dependent measures. There was no significant difference between the Intoxicated and Sober subjects regarding the amount of information recalled or their average accuracy. The main effect for lighting conditions and gender differences were also not significant.
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A systematic approach was developed to investigate the stability of gentamicin sulfate (GS) and GS/poly (lactic-co-glycolic acid) (PLGA) coatings on hydroxyapatite surfaces. The influence of environmental factors (light, humidity, oxidation and heat) upon degradation of the drug in the coatings was investigated using liquid chromatography with evaporative light scattering detection and mass spectrometry. GS coated rods were found to be stable across the range of environments assessed, with only an oxidizing atmosphere resulting in significant changes to the gentamicin composition. In contrast, rods coated with GS/PLGA were more sensitive to storage conditions with compositional changes being detected after storage at 60 °C, 75% relative humidity or exposure to light. The effect of γ-irradiation on the coated rods was also investigated and found to have no significant effect. Finally, liquid chromatography–mass spectrometry analysis revealed that known gentamines C1, C1a and C2 were the major degradants formed. Forced degradation of gentamicin coatings did not produce any unexpected degradants or impurities.
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The increasing interest in coral culture for biotechnological applications, to supply the marine aquarium trade, or for reef restoration programs, has prompted researchers to optimize coral culture protocols, with emphasis to ex situ production. When cultured ex situ, the growth performance of corals can be influenced by several physical, chemical and biological parameters. For corals harbouring zooxanthellae, light is one of such key factors, as it can influence the photosynthetic performance of these endosymbionts, as well as coral physiology, survival and growth. The economic feasibility of ex situ coral aquaculture is strongly dependent on production costs, namely those associated with the energetic needs directly resulting from the use of artificial lighting systems. In the present study we developed a versatile modular culture system for experimental coral production ex situ, assembled solely using materials and equipment readily available from suppliers all over the world; this approach allows researchers from different institutions to perform truly replicated experimental set-ups, with the possibility to directly compare experimental results. Afterwards, we aimed to evaluate the effect of contrasting Photosynthetically Active Radiation (PAR) levels, and light spectra emission on zooxanthellae photochemical performance, through the evaluation of the maximum quantum yield of PSII (Fv/Fm) (monitored non-invasively and non-destructively through Pulse Amplitude Modulation fluorometry, PAM), chlorophyll a content (also determined non-destructively by using the spectral reflectance index Normalized Difference Vegetation Index, NDVI), photosynthetic and accessory pigments, number of zooxanthellae, coral survival and growth. We studied two soft coral species, Sarcophyton cf. glaucum and Sinularia flexibilis, as they are good representatives of two of the most specious genera in family Alcyoniidae, which include several species with interest for biotechnological applications, as well as for the marine aquarium trade; we also studied two commercially important scleractinian corals: Acropora formosa and Stylophora pistillata. We used different light sources: hydrargyrum quartz iodide (HQI) lamps with different light color temperatures, T5 fluorescent lamps, Light Emitting Plasma (LEP) and Light Emitting Diode (LED). The results achieved revealed that keeping S. flexibilis fragments under the same light conditions as their mother colonies seems to be photobiologically acceptable for a short-term husbandry, notwithstanding the fact that they can be successfully stocked at lower PAR intensities. We also proved that low PAR intensities are suitable to support the ex situ culture S. cf. glaucum in captivity at lower production costs, since the survival recorded during the experiment was 100%, the physiological wellness of coral fragments was evidenced, and we did not detect significant differences in coral growth. Finally, we concluded that blue light sources, such as LED lighting, allow a higher growth for A. formosa and S. pistillata, and promote significant differences on microstructure organization and macrostructure morphometry in coral skeletons; these findings may have potential applications as bone graft substitutes for veterinary and/or other medical uses. Thus, LED technology seems to be a promising option for scleractinian corals aquaculture ex situ.