998 resultados para organic components
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Heat shock and salicylic acid have been studied on shelf-life extension of fruits. The benefits of these techniques have been related to their effect on inducing physiological defense responses against the oxidative stress and pathogen development. The objective of this study was to evaluate the effect of heat shock and salicylic acid on the postharvest preservation and contents of total phenolics, anthocyanins, ascorbic acid, fresh weight loss and microbiological quality of organic strawberries cv. Dover. Strawberries produced organically and stored at 5 ºC were subjected to heat shock (45 ºC ± 3 ºC for 3 h), application of salicylic acid (soaking in 2.0 mmol L-1 solution), heat shock in combination with salicylic acid and control. After treatment, the fruits were packed and stored in a climatic chamber at 5 ºC ± 2 ºC. At 1, 7 and 14 days, the experimental units were removed from refrigeration and kept at room temperature of approximately 20 ºC for two days. There was no effect of treatments on fresh weight loss, incidence of pathogens or chemical variations in strawberry fruits during the storage period. In natural conditions, organically grown strawberries remained in good condition for sale up to seven days of storage in all treatments.
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Abstract: There is a need for heat tolerant wheat cultivars adapted to the expansion of cultivation areas in warmer regions due to the high demand of this cereal for human consumption. The objective of this study was to evaluate the effect of high temperatures on grain yield and yield components of wheat and characterize heat tolerant wheat genotypes at different development stages. The genotypes were evaluated in the field with and without heat stress. High temperatures reduced the number of spikelets per spike (21%), number of grains per spike (39%), number of grains per spikelet (23%), 1000-grain weight (27%) and grain yield (79%). Cultivars MGS 1 Aliança, Embrapa 42, IAC 24-Tucuruí and IAC 364-Tucuruí III are the most tolerant to heat stress between the stages double ridge and terminal spikelet; MGS 1 Aliança, BRS 264, IAC 24-Tucuruí, IAC 364-Tucuruí III and VI 98053, between meiosis and anthesis; and BRS 254, IAC-24-Tucuruí, IAC-364-Tucuruí III and VI 98053, between anthesis and physiological maturity. High temperatures reduce grain yield and yield components. The number of grains per spike is the most reduced component under heat stress. The genotypes differed in tolerance to heat stress in different developmental stages.
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ABSTRACTAiming to compare three different methods for the determination of organic carbon (OC) in the soil and fractions of humic substances, seventeen Brazilian soil samples of different classes and textures were evaluated. Amounts of OC in the soil samples and the humic fractions were measured by the dichromate-oxidation method, with and without external heating in a digestion block at 130 °C for 30 min; by the loss-on-ignition method at 450 °C during 5 h and at 600 °C during 6 h; and by the dry combustion method. Dry combustion was used as reference in order to measure the efficiency of the other methods. Soil OC measured by the dichromate-oxidation method with external heating had the highest efficiency and the best results comparing to the reference method. When external heating was not used, the mean recovery efficiency dropped to 71%. The amount of OC was overestimated by the loss-on-ignition methods. Regression equations obtained between total OC contents of the reference method and those of the other methods showed relatively good adjustment, but all intercepts were different from zero (p < 0.01), which suggests that more accuracy can be obtained using not one single correction factor, but considering also the intercept. The Walkley-Black method underestimated the OC contents of the humic fractions, which was associated with the partial oxidation of the humin fraction. Better results were obtained when external heating was used. For the organic matter fractions, the OC in the humic and fulvic acid fractions can be determined without external heating if the reference method is not available, but the humin fraction requires the external heating.
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ABSTRACT Soils of tropical regions are more weathered and in need of conservation managements to maintain and improve the quality of its components. The objective of this study was to evaluate the availability of K, the organic matter content and the stock of total carbon of an Argisol after vinasse application and manual and mechanized harvesting of burnt and raw sugarcane, in western São Paulo.The data collection was done in the 2012/2013 harvest, in a bioenergy company in Presidente Prudente/SP. The research was arranged out following a split-plot scheme in a 5x5 factorial design, characterized by four management systems: without vinasse application and harvest without burning; with vinasse application and harvest without burning; with vinasse application and harvest after burning; without vinasse application and harvest after burning; plus native forest, and five soil sampling depths (0-10 10-20, 20-30, 30-40, 40-50 cm), with four replications. In each treatment, the K content in the soil and accumulated in the remaining dry biomass in the area, the levels of organic matter, organic carbon and soil carbon stock were determined. The mean values were compared by Tukey test. The vinasse application associated with the harvest without burning increased the K content in soil layers up to 40 cm deep. The managements without vinasse application and manual harvest after burning, and without vinasse application with mechanical harvesting without burning did not increase the levels of organic matter, organic carbon and stock of total soil organic carbon, while the vinasse application and harvest after burning and without burning increased the levels of these attributes in the depth of 0-10 cm.
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ABSTRACT The sunflower plant is an oilseed crop that has aroused a great interest in the Brazilian and international scenery especillay because of the possibility of using its oil for biodiesel production. The objective of this study was to evaluate productivity and yield components of Embrapa 122 sunflower according to the spatial arrangement. Treatments were arranged in 4 x 4 factorial arrangement, which are the four spacings between rows (0.30; 0.50; 0.70 and 0.90 m) and four sowing densities (30,000; 45,000; 60,000 and 75,000 plants ha-1). The experiment was carried out in a complete randomized block design with four replications. The experiments were conducted in the experimental area of the Plant Science Department in Fortaleza, State of Ceará-Brazil and on the Curu Vale Experimental Farm in Pentecoste, State of Ceará-Brazil. Productivity and the following production components were analyzed in the end of the crop cycle: harvested capitula, capitulum diameter, capitulum mass, achene mass per capitulum, mass of 100 achenes, achenes per capitulum, harvest index and oil content in the achenes. The experiments were analyzed jointly in relation to the cropping area and the data submitted to analysis of variance and quantitative factors tested by polynomial regression. The variables, spacing, density and cropping area did not interact with these variables and the spatial arrangement of the plants affected only the components. The cropping area influences the productive behavior of sunflower Embrapa 122. The spatial arrangement of the plants of sunflower of variety Embrapa 122 influences yield components but does not affect productivity.
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Existing studies on global sourcing strategy have implicitly adopted a cJosed-systems perspective in which sourcing activities are managed within a multinational company across national boundaries. Produd and process innovations and components procurement that are jointly managed by a consortium of cooperating firms have not been examined. In this paper, we empiricallyexamine the issues concerning sourcing partnerships in an open-systems perspective. Findings suggest that even in a sourcing partnership arrangement with a foreign supplier, the principal firm's ability to procure and control the supply of major components has a positive bearing on its market performance.
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In the printing industry, volatile organic compounds main sources are the uses of organic solvents, fountain solutions and cleaning agents. Nowadays, one circumstance which might confuse the exposure reality is that the majority of solvents which are often used have a faint odour. Therefore, the conditions at offset printing in regard to solvent exposure may seem acceptable to workers. Fortunately, general ventilation and local exhaust systems have also become more common, and new printing machines, often with automatic cleaning, have entered the market. The health effects of volatile organic solvents are dependent on the chemicals involved but, normally, are associated with affecting the nervous system, the liver and also the kidneys. The purpose of this study was to document the conditions regarding exposure to volatile organic compounds in an offset printing unit and to permit identify task with higher exposure and with priority for preventive measures application. Exposure assessment was done before and after installation of general ventilation and local exhaust equipments and during printing and cleaning procedure.
Ventilation influence in occupational exposure to fungi and volatile organic compounds: poultry case
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Introduction - In poultry houses, large-scale production has led to increased bird densities within buildings. Such high densities of animals kept within confined spaces are a source of human health problems related to occupational organic dust exposure. This organic dust is composed of both non-viable particles and viable particulate matter (also called bioaerosols). Bioaerosols are comprised by airborne bacteria, fungi, viruses and their by-products, endotoxins and mycotoxins. Exposure to fungi in broiler houses may vary depending upon the applied ventilation system. Ventilation can be an important resource in order to reduce air contamination in these type of settings. Nevertheless, some concerns regarding costs, sensitivity of the animal species to temperature differences, and also the type of building used define which type of ventilation is used. Aim of the study - A descriptive study was developed in one poultry unit aiming to assess occupational fungal and volatile organic compounds (VOCs) exposure.
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Demand for power is growing every day, mainly due to emerging economies in countries such as China, Russia, India, and Brazil. During the last 50 years steam pressure and temperature in power plants have been continuously raised to improve thermal efficiency. Recent efforts to improve efficiency leads to the development of a new generation of heat recovery steam generator, where the Benson once-through technology is applied to improve the thermal efficiency. The main purpose of this paper is to analyze the mechanical behavior of a high pressure superheater manifold by applying finite element modeling and a finite element analysis with the objective of analyzing stress propagation, leading to the study of damage mechanism, e.g., uniaxial fatigue, uniaxial creep for life prediction. The objective of this paper is also to analyze the mechanical properties of the new high temperature resistant materials in the market such as 2Cr Bainitic steels (T/P23 and T/P24) and also the 9-12Cr Martensitic steels (T/P91, T/P92, E911, and P/T122). For this study the design rules for construction of power boilers to define the geometry of the HPSH manifold were applied.
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The present work involves the use of p-tert-butylcalix[4,6,8]arene carboxylic acid derivatives ((t)Butyl[4,6,8]CH2COOH) for selective extraction of hemoglobin. All three calixarenes extracted hemoglobin into the organic phase, exhibiting extraction parameters higher than 0.90. Evaluation of the solvent accessible positively charged amino acid side chains of hemoglobin (PDB entry 1XZ2) revealed that there are 8 arginine, 44 lysine and 30 histidine residues on the protein surface which may be involved in the interactions with the calixarene molecules. The hemoglobin-(t)Butyl[6]CH2COOH complex had pseudoperoxidase activity which catalysed the oxidation of syringaldazine in the presence of hydrogen peroxide in organic medium containing chloroform. The effect of pH, protein and substrate concentrations on biocatalysis was investigated using the hemoglobin-(t)Butyl[6]CH2COOH complex. This complex exhibited the highest specific activity of 9.92 x 10(-2) U mg protein(-1) at an initial pH of 7.5 in organic medium. Apparent kinetic parameters (V'(max), K'(m), k'(cat) and k'(cat)/K'(m)) for the pseudoperoxidase activity were determined in organic media for different pH values from a Michaelis-Menten plot. Furthermore, the stability of the protein-calixarene complex was investigated for different initial pH values and half-life (t(1/2)) values were obtained in the range of 1.96 and 2.64 days. Hemoglobin-calixarene complex present in organic medium was recovered in fresh aqueous solutions at alkaline pH, with a recovery of pseudoperoxidase activity of over 100%. These results strongly suggest that the use of calixarene derivatives is an alternative technique for protein extraction and solubilisation in organic media for biocatalysis.
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OBJECTIVE: The aim of the study was to identify the variables that predict the revolving door phenomenon in psychiatric hospital at the moment of a second admission. METHODS: The sample consisted of 3,093 patients who have been followed during 5 to 24 years after their first hospital admission due to schizophrenia, and affective or psychotic disorders. Those who had had four or more admissions during the study period were considered as revolving door patients. Logistic regression analyses were used to assess the impact of gender, age, marital status, urban conditions, diagnosis, mean period of stay on the first admission, interval between the first and second admissions on the patterns of hospitalization. RESULTS: The variables with the highest predictive power for readmission were the interval between first and second admissions, and the length of stay in the first admission. CONCLUSIONS: These data may help public health planners in providing optimal care to a small group of patients with more effective utilization of the available services.
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In the management of solid waste, pollutants over a wide range are released with different routes of exposure for workers. The potential for synergism among the pollutants raises concerns about potential adverse health effects, and there are still many uncertainties involved in exposure assessment. In this study, conventional (culture-based) and molecular real-time polymerase chain reaction (RTPCR) methodologies were used to assess fungal air contamination in a waste-sorting plant which focused on the presence of three potential pathogenic/toxigenic fungal species: Aspergillus flavus, A. fumigatus, and Stachybotrys chartarum. In addition, microbial volatile organic compounds (MVOC) were measured by photoionization detection. For all analysis, samplings were performed at five different workstations inside the facilities and also outdoors as a reference. Penicillium sp. were the most common species found at all plant locations. Pathogenic/toxigenic species (A. fumigatus and S. chartarum) were detected at two different workstations by RTPCR but not by culture-based techniques. MVOC concentration indoors ranged between 0 and 8.9 ppm (average 5.3 ± 3.16 ppm). Our results illustrated the advantage of combining both conventional and molecular methodologies in fungal exposure assessment. Together with MVOC analyses in indoor air, data obtained allow for a more precise evaluation of potential health risks associated with bioaerosol exposure. Consequently, with this knowledge, strategies may be developed for effective protection of the workers.
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The production of MVOC by fungi has been taken into account especially from the viewpoint of indoor pollution with microorganisms but the relevance of fungal metabolites in working environments has not been sufficiently studied. The purpose of this study was to assess exposure to MVOCs in a waste-handling unit. It was used Multirae equipment (RAE Systems) to measured MVOCs concentration with a 10.6 eV lamps. The measurements were done near workers nose and during the normal activities. All measurements were done continuously and had the duration of 5 minutes at least. It was consider the higher value obtained in each measurement. In addition, for knowing fungi contamination, five air samples of 50 litres were collected through impaction method at 140 L/minute, at one meter tall, on to malt extract agar with the antibiotic chloramphenicol (MEA). MVOCs results range between 4.7 ppm and 8.9 ppm in the 6 locations consider. These results are eight times higher than normally obtained in indoor settings. Considering fungi results, two species were identified in air, being the genera Penicillium found in all the samples in uncountable colonies and Rhizopus only in one sample (40 UFC/m3). These fungi are known as MVOCs producers, namely terpenoids, ketones, alcohols and others. Until now, there has been no evidence that MVOCs are toxicologically relevant, but further epidemiological research is necessary to elucidate their role on human’s health, particularly in occupational settings where microbiological contamination is common. Additionally, further research should concentrate on quantitative analyses of specific MVOCs.
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Tuberculosis (TB) is a worldwide infectious disease that has shown over time extremely high mortality levels. The urgent need to develop new antitubercular drugs is due to the increasing rate of appearance of multi-drug resistant strains to the commonly used drugs, and the longer durations of therapy and recovery, particularly in immuno-compromised patients. The major goal of the present study is the exploration of data from different families of compounds through the use of a variety of machine learning techniques so that robust QSAR-based models can be developed to further guide in the quest for new potent anti-TB compounds. Eight QSAR models were built using various types of descriptors (from ADRIANA.Code and Dragon software) with two publicly available structurally diverse data sets, including recent data deposited in PubChem. QSAR methodologies used Random Forests and Associative Neural Networks. Predictions for the external evaluation sets obtained accuracies in the range of 0.76-0.88 (for active/inactive classifications) and Q(2)=0.66-0.89 for regressions. Models developed in this study can be used to estimate the anti-TB activity of drug candidates at early stages of drug development (C) 2011 Elsevier B.V. All rights reserved.
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Farmers are occupationally exposed to many respiratory hazards at work and display higher rates of asthma and respiratory symptoms than other workers. Dust is one of the components present in poultry production that increases risk of adverse respiratory disease occurrence. Dust originates from poultry residues, molds, and feathers and is biologically active as it contains microorganisms. Exposure to dust is known to produce a variety of clinical responses, including asthma, chronic bronchitis, chronic airways obstructive disease (COPD), allergic alveolitis, and organic dust toxic syndrome (ODTS). A study was developed to determine particle contamination in seven poultry farms and correlate this with prevalence rate of respiratory defects and record by means of a questionnaire the presence of clinical symptoms associated with asthma and other allergy diseases by European Community Respiratory Health Survey. Poultry farm dust contamination was found to contain higher concentrations of particulate matter (PM) PM5 and PM10. Prevalence rate of obstructive pulmonary disorders was higher in individuals with longer exposure regardless of smoking status. In addition, a high prevalence for asthmatic (42.5%) and nasal (51.1%) symptoms was noted in poultry workers. Data thus show that poultry farm workers are more prone to suffer from respiratory ailments and this may be attributed to higher concentrations of PM found in the dust. Intervention programs aimed at reducing exposure to dust will ameliorate occupational working conditions and enhance the health of workers.