10 resultados para Differencein-in-Difference estimation (DID)
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
Flowering is controlled by several environmental and endogenous factors, usually associated with a complex network of metabolic mechanisms. The gene characterization in Arabidopsis model has provided much information about the genetic and molecular mechanisms that control flowering process. Some of these genes had been found in rice and maize. However, in sugarcane this processe is not well known. It is known that early flowering may reduce its production up to 60% at northeast conditions. Considering the impact of early flowering in sugarcane production, the aim of this work was to make the gene characterization of two cDNAs previously identified in subtractive cDNA libraries: scPKCI and scSHAGGY. The in silico analysis showed that these two cDNAs presented both their sequence and functional catalytic domains conserved. The results of transgenic plants containing the overexpression of the gene cassette scPKCI in sense orientation showed that this construction had a negative influence on the plant development as it was observed a decrease in plant height and leaf size. For the scPKCI overexpression in antisense orientation it was observed change in the number of branches from T1 transgenic plants, whereas transgenic T2 plants showed slow development during germination and initial stages of development. The other cDNA analyzed had homology to SHAGGY protein. The overexpression construct in sense orientation did not shown any effect on development. The only difference observed it was an increase in stigma structure. These results allowed us to propose a model how these two genes may be interact and affect floweringdevelopment.
Resumo:
Helicobacter pylori is a spiral, Gram negative, mobile, and microaerophilic bacteria recognized as a major cause of gastritis, ulcer, gastric cancer, and gastric low grade, B cell, mucosa – associated lymphoid tissue (MALT) lymphoma, constituting an important microorganism in medical microbiology. Its importance comes from the difficulty of treatment because the requirement of multiple drugs use, besides the increasing emergence of resistant and multiresistant strains to antibiotics used in th e clinic. In order to expand safe and effective therapeutic options , chemical studies on medicinal plants by obtaining extracts, fractions, isolated compounds or essential oils with some biological activity has been intensified . Given the above, the objective was to evaluate the inhi bitory activity of organic extracts derived from Syzygium cumini and Encholirium spectabile, with antiulcer history, and the essential oil, obtained from S. cumini, against H. pylori (ATCC 43504) by the disk diffusion method, for qualitative evaluation, an d determination of minimum inhibitory concentration (MIC) using the broth microdilution method, for quantitative analysis. Also was evaluated the extracts in vitro toxicity by a hemolytic assay using sheep red blood cells, and VERO and HeLa cells using the MTT assay to analyze cell viability. The extracts of both plant used in antimicrobial assays did not inhibit bacterial growth, however the essential oil of S. cumini (SCFO) proved effective, showing MIC value of 205 μg/mL (0.024 % dilution of the original oil). In the hemolytic assay, the same oil shows moderate toxicity, by promote 25% hemolysis at 1000 μg/mL. Regarding the cytotoxicity in cell culture, the SCFO, at 260 μg/mL, affected the cell viability around 80% of HeLa and 50% of VERO cells. So the oi l obtained from S. cumini leaves has antimicrobial activity against H. pylori and cytotoxicity potential, suggesting a source of new molecule drug candidates, since new stages of toxicity in vitro and in vivo, as well, chemical characterization be evaluate d. Moreover, the development of a prospective drug delivery system can result in a prototype to be used in preclinical tests.
Resumo:
Leptospirosis is a worldwide zoonosis of considerable medical and economical importance that affects humans in both urban and rural contexts, as well as domestic animals and wild fauna. Leptospira interrogans is the causative agent and is transmitted to humans by indirect contact with contaminated soil or water. The clinical syndromes include sub clinical infection, self-limited anicteric febrile illness, and severe and potentially fatal illness, known as Weil´s syndrome. In developed countries, leptospirosis is related to occupational or recreational activities while in developing countries, outbreaks occur during floods. In those regions, traditional strategies to prevent the transmission are difficulties to be implemented because of costs and lack of community acceptance. In addition, no efficient vaccine is available for human use. Several studies have suggested that chemoprophylaxis with doxycycline pre and post-exposure may be effective to prevent leptospirosis. Leptospirosis has been reported in rural areas of the State of Rio Grande do Norte, Brazil since 1985 in rice farmers who present the anicteric illness. The disease cause great social and economics impact. The study was conducted in São Miguel where an epidemic of leptospirosis in rice farmers was reported. The main objective was to determine the efficacy of doxycycline in preventing Leptospira exposure. A taxa de soroprevalência de leptospirose na população estudada antes e após a colheita foi de 14,2% (n=22) e de 16.6% (n=27) respectivamente. Anti-Leptospira serology was determined for 61 subjects in two instances, pre and post-exposure to potential contaminated water. There was an increased risk of 29.0 per cent in acquiring infection for individuals that did not use doxycycline. In addition, an increased risk of 30.0 % observed in farmers who did not use protection when exposed to Leptospira. The adhesion to preventive chemoprophylaxis was 55.7%. Therefore doxycycline, under specific circunstances appears to be an effective alternative to protect against leptosprirosis infection. A large sample composed of individuals to adhere to preventive therapy is needed to define time, dosage and length of use of doxycycline in this area
Resumo:
Chitosan is a natural polymer, biodegradable, nontoxic, high molecular weight derived from marine animals, insects and microorganisms. Oligomers of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) have interesting biological activities, including antitumor effects, antimicrobial activity, antioxidant and others. The alternative proposed by this work was to study the viability of producing chitooligosaccharides using a crude enzymes extract produced by the fungus Metarhizium anisopliae. Hydrolysis of chitosan was carried out at different times, from 10 to 60 minutes to produce chitooligosaccharides with detection and quantification performed by High Performace Liquid Chromatography (HPLC). The evaluation of cytotoxicity of chitosan oligomers was carried out in tumor cells (HepG2 and HeLa) and non-tumor (3T3). The cells were treated for 72 hours with the oligomers and cell viability investigated using the method of MTT. The production of chitosan oligomers was higher for 10 minutes of hydrolysis, with pentamers concentration of 0.15 mg/mL, but the hexamers, the molecules showing greater interest in biological properties, were observed only with 30 minutes of hydrolysis with a concentration of 0.004 mg/mL. A study to evaluate the biological activities of COS including cytotoxicity in tumor and normal cells and various tests in vitro antioxidant activity of pure chitosan oligomers and the mixture of oligomers produced by the crude enzyme was performed. Moreover, the compound with the highest cytotoxicity among the oligomers was pure glucosamine, with IC50 values of 0.30; 0.49; 0.44 mg/mL for HepG2 cells, HeLa and 3T3, respectively. Superoxide anion scavenging was the mainly antioxidant activity showed by the COS and oligomers. This activity was also depending on the oligomer composition in the chitosan hydrolysates. The oligomers produced by hydrolysis for 20 minutes was analyzed for the ability to inhibit tumor cells showing inhibition of proliferation only in HeLa cells, did not show any effect in HepG2 cells and fibroblast cells (3T3)
Resumo:
This Thesis presents the elaboration of a methodological propose for the development of an intelligent system, able to automatically achieve the effective porosity, in sedimentary layers, from a data bank built with information from the Ground Penetrating Radar GPR. The intelligent system was built to model the relation between the porosity (response variable) and the electromagnetic attribute from the GPR (explicative variables). Using it, the porosity was estimated using the artificial neural network (Multilayer Perceptron MLP) and the multiple linear regression. The data from the response variable and from the explicative variables were achieved in laboratory and in GPR surveys outlined in controlled sites, on site and in laboratory. The proposed intelligent system has the capacity of estimating the porosity from any available data bank, which has the same variables used in this Thesis. The architecture of the neural network used can be modified according to the existing necessity, adapting to the available data bank. The use of the multiple linear regression model allowed the identification and quantification of the influence (level of effect) from each explicative variable in the estimation of the porosity. The proposed methodology can revolutionize the use of the GPR, not only for the imaging of the sedimentary geometry and faces, but mainly for the automatically achievement of the porosity one of the most important parameters for the characterization of reservoir rocks (from petroleum or water)
Resumo:
The flowering is a physiological process that it is vital for plants. This physiological process has been well studied in the plant model Arabidopsis, but in sugarcane this process is not well known. The transition of the shoot apical meristem from vegetative to flowering is a critical factor for plant development. At Brazil northeastern region, the transition to flowering in sugarcane has an important effect as it may reduce up to 60% its production. This is a consequence of the sugar translocation from stalks to the shoot apical meristem which is necessary during the flowering process. Therefore, the aim of this work was to explore and analyze cDNAs previously identified using subtractive cDNA libraries. The results showed that these cDNAs showed differential expression profile in varieties of sugarcane (early x late flowering). The in silico analysis suggested that these cDNAs had homology to calmodulin, NAC transcription factor and phosphatidylinositol, a SEC14, which were described in the literature as having a role in the process of floral development. To better understand the role of the cDNA homologous to calmodulin, tobacco plants were transformed with overexpression cassettes in sense and antissense orientation. Plants overexpressing the cassette in sense orientation did not flowered, while plants overexpressing the cassette in the antissense orientation produced flowers. The data obtained in this study suggested the possible role from CAM sequence, SEC14 and NAC in the induction/floral development pathway in sugarcane, this is the first study in order to analyze these genes in the sugarcane flowering process.
Resumo:
Radiobiocomplexes are used to obtain images in nuclear medicine and employed in basic research. Blood constituents labeled with technetium-99m (99mTc) have also been employed as radiobiocomplexes and used also experimental model for evaluation of the biological effects of natural or synthetic drugs. The analysis of the morphology and the morphometrics parameters (perimeter/área ratio) can be used to evaluate the effects of drugs upon the structure of the membrane of red blood cells. Cinnamomum zeylanicum (cinnamon) is a spice used as herbal medicine to treat diseases. The aim of this study was to evaluate the effect of in vitro and in vivo treatment with an aqueous cinnamon extract on the labeling of blood constituents with 99mTc and on the morphology of red blood cells from Wistar rats. In the in vitro treatment, isolated blood sample from animals were incubated with cinnamon extract. In the in vivo treatment, blood samples were also withdrawn from animals treated with cinnamon extract. In both cases, the radiolabeling of blood constituents was done. The morphological analysis of red blood cells was also done. As control, blood or animals treated with NaCl 0.9%. The data obtained on the labeling of blood constituents with 99mTc experiments indicated that the in vitro treatment with cinnamon extract was capable to decrease signiicantly (p<0.05) the percentage of radioactivity in cellular compartments and on the fixation of cellular and plasma proteins. These effects were not observed on the in vivo treatment. The results obtained for the morphology of red blood cells suggest that the in vitro and in vivo treatments did not alter the morphology and the perimeter/area ratio. The in vitro treatment with aqueous cinnamon extract could affect the membrane structures related with the oxidation status of the stannous ion pertechnetate ion, altering the labeling of blood constituentes with 99mTc. This study was a multidisciplinary experimental research. It was developed with the contribution of the different Departments and Services of the Hospital Universitário Pedro Ernesto of the Universidade do Estado do Rio de Janeiro
Resumo:
The objective of this work was the development and improvement of the mathematical models based on mass and heat balances, representing the drying transient process fruit pulp in spouted bed dryer with intermittent feeding. Mass and energy balance for drying, represented by a system of differential equations, were developed in Fortran language and adapted to the condition of intermittent feeding and mass accumulation. Were used the DASSL routine (Differential Algebraic System Solver) for solving the differential equation system and used a heuristic optimization algorithm in parameter estimation, the Particle Swarm algorithm. From the experimental data food drying, the differential models were used to determine the quantity of water and the drying air temperature at the exit of a spouted bed and accumulated mass of powder in the dryer. The models were validated using the experimental data of drying whose operating conditions, air temperature, flow rate and time intermittency, varied within the limits studied. In reviewing the results predicted, it was found that these models represent the experimental data of the kinetics of production and accumulation of powder and humidity and air temperature at the outlet of the dryer
Resumo:
Eutrophication is a growing process present in the water sources located in the northeast of Brazil. Among the main consequences of these changes in trophic levels of a water source, stands out adding complexity to the treatment to achieve water standards. By these considerations, this study aimed to define, on a laboratory scale, products and operational conditions to be applied in the processing steps using raw water from Gargalheiras dam, RN, Brazil. The dam mentioned shows a high number of cyanobacteria, with a concentration of cells / ml higher than that established by Decree No. 518/04 MS. The same source was also considered by the state environmental agency in 2009 as hypereutrophic. The static tests developed in this research simulated direct filtration (laboratory filters) and pre-oxidation with chlorine and powdered activated carbon adsorption. The research included the evaluation of the coagulants aluminum hydrochloride (HCA) and alum (SA). The development of the research investigated the conditions for rapid mixing, the dosages of coagulants and pHs of coagulation by the drawing of diagrams. The interference of filtration rate and particle size of filtering means were evaluated as samples and the time of contact were tested with chlorine and activated carbon. By the results of the characterization of the raw water source it was possible to identify the presence of a high pH (7.34). The true color was significant (29 uH) in relation to the apparent color and turbidity (66 uH and 13.60 NTU), reflecting in the measurement of organic matter: MON (8.41 mg.L-1) and Abs254 (0.065 cm-1). The optimization of quick mix set time of 17", the speed gradient of 700 s-1 in the coagulation with HCA and the time of 20" with speed gradient of 800 s-1 for SA. The smaller particle sizes of sand filtering means helped the treatment and the variation in filtration rate did not affect significantly the efficiency of the process. The evaluation of the processing steps found adjustment in standard color and turbidity of the Decree nº 518/04 MS, taking in consideration the average values found in raw water. In the treatment using the HCA for direct filtration the palatable pattern based on the apparent color can be achieved with a dose of 25 mg L-1. With the addition of pre-oxidation step, the standard result was achieved with a reduced dose for 12 mgHCA.L-1. The turbidity standard for water was obtained by direct filtration when the dose exceeds 25 mg L-1 of HCA. With pre-oxidation step there is the possibility of reducing the dose to 20 mg L-1.The addition of CAP adsorption, promoted drinking water for both parameters, with even lower dosage, 13 mg L-1 of HCA. With coagulation using SA removal required for the parameter of apparent color it was achieved with pre-oxidation and 22 mgSA.L-1. Despite the satisfactory results of treatment with the alum, it was not possible to provide water with turbidity less than 1.00 NTU even with the use of all stages of treatment
Resumo:
Experience in the use of stabilization ponds shows that this is a system with low cost, easy operation and maintenance and suitable for tropical countries. One of its disadvantages is due to high concentrations of suspended solids, mainly due to algal biomass in the effluents. Accordingly, the dissolved air flotation has been shown to be an efficient post-treatment technology. However, the efficiency of this process is related to coagulation and flocculation steps, as well as the adjustment of the involved variables in the process. The objective of this work was to evaluate the algae removal efficiency from wastewater stabilization ponds and the influence of the factors involved in the process using dissolved air flotation. For this, we used primary facultative and maturation effluents of ETE Ponta Negra in Natal. We did tests of coagulation, flocculation and flotation with the samples, using the equipment flotatest. In this process were tested coagulants aluminum sulfate and ferric chloride, and varied the factors pH, coagulant concentration, polymer concentration and rate of recirculation. At the end of the experiments were analyzed turbidity, suspended solids, color, COD and chlorophyll "a". These results were submitted to descriptive statistics to verify the efficiency of the process in general, and regression analysis to identify models that describe the process and demonstrate the factors that have greater influence on flotation. After step methodology, high values were found removal efficiency of suspended solids, reaching values greater than 90% in the best cases. It was concluded that flotation is more efficient in the facultative pond effluent using ferric chloride, and the variability of algae may negatively influence the process. Regression analyzes showed that pH is the most influential variable in the coagulation-flocculation-flotation, and its optimal value among the tested is 5.5 for both coagulants