40 resultados para COLISÕES NUCLEARES
Resumo:
The study of solar neutrinos is very important to a better comprehension of the set of nuclear reactions that occurs inside the Sun and in solar type stars. The ux of neutrinos provides a better comprehension of the stellar structure as a whole. In this dissertation we study the ux of neutrinos in a solar model, addressing the neutrino oscillation, analyzing with the intention of determining and verify the distribution from a statistical point of view, since this ux depends on the particles intrinsic velocity distributions in stellar plasma. The main tool for this analysis was the Toulouse-Geneva Stellar Evolution Code, or TGEC, which allow us to obtain the neutrino ux values per reaction and per layer inside the Sun, allowing us to compare the observational results for the neutrino ux detected on experiments based on Cl37 (Homestake), Ga71 (SAGE, Gallex/GNO) and water (SNO). Our results show the nal distribution for neutrino ux as a function of the depth using the coordinates of mass and radius. The dissertation also shows that the equations for this ux are present in TGEC.
Resumo:
It is presently assumed that the Borborema Province resulted from a complex collisional process associated with the convergent movement of plates, possibly involving amalgamation and accretion of microplates. This process was consolidated at the end of the Brasiliano event. It is investigated the possible limits for the tectonostratigraphic terranes in the northern portion of the province based on an integrated study of geological and gravity data. The study area comprises the portion of the Borborema Province located north of the Patos Lineament, limited by longitudes 33º00 W and 43º29 44"W and latitudes 1º36 S and 8º00 S. A revision of the regional geology allowed to identify areas presenting contrasting geological attributes, possibly representing different terranes whose limits are always shear zones of Brasiliano-age. The Sobral-Pedro II shear zone is the only one undoubtedly presenting geological attributes of sutures zones. The other shear zones are very likely associated with a geodinymic context of accretion, involving oblique collisions (docking), transcurrent and/or transforming sutures, and deep intracrustal shear zones. The gravity data contributed as a tool to identify strong lateral contrasts of density inside the upper crust possibly associated with crustal blocks tectonically juxtaposed. The dominant long wavelength anomaly in the Bouguer anomaly map is an expressive gradient, grossly parallel to the continental margin, caused by density variation across the crust-mantle interface in the transition from the continental crust to the oceanic crust originated by the separation between South America and Africa. Medium to small wavelength anomalies are due to intracrustal heterogeneities such as different Precambrian crustal blocks, Brasiliano-age granites and Mesozoic sedimentary basins. A regional-residual separation of the Bouguer anomaly map was performed in order to enhance in the residual map the effect due to intracrustal heterogeneities. The methodology used for this separation was a robust polinomial fitting. The inversion of residual gravity field resulted in a density contrast map (Δρ), in an equivalent layer that provided more accurated anomalies contours and consolidated the model which the sources of residual anomalies are located in the upper part of the present crust. Based on the coincidence of gravity lineaments in the residual map and Brasiliano shear zones, and using additional geological information, the following shear zones are proposed as limits between terranes: Patos shear zone, Sobral-Pedro II shear zone, Picuí-João Câmara shear zone, Remígio-Pocinhos shear zone, Senador Pompeu shear zone, Tauá shear zone, and Portalegre shear zone. Based on the geological/geophysical information it is attributed a higher level of confidence to the first three proposed limits(Patos, Sobral Pedro II, and Picuí-João Câmara shear zones). From west to east, these shear zones individualize the following terranes: Northwest of Ceará terrane, Central Ceará terrane, Tauá terrane, Orós-Jaguaribe terrane, Seridó terrane, and São José de Campestre terrane. In our study, the Rio Piranhas and Patos terranes are questioned because their previously proposed limits do not present good geological and gravimetric evidences. On the other hand, the previously proposed Cearense terrane is now subdivided into Central Ceará and Tauá terranes. Two residual gravity profiles located in the Seridó belt were interpreted using 2 ½ D direct gravity modeling. The main result of the modeling process is that all anomalies, with the exception of one, can be explained by outcroppring bodies, therefore restricted to the upper part of the present crust
Resumo:
In this study, a BCR-ABL expressing human chronic myelogenous leukaemia cell line (K562) was used to investigate the antitumoral potential of a novel lectin (CvL) purified from the marine sponge Cliona varians. CvL inhibited the growth of K562 cells with an IC50 value of 70 g/ml, but was ineffective to normal human peripheral blood lymphocytes in the same range of concentrations tested (180 g/ml). Cell death occurred after 72 h of exposure to the lectin and with sign of apoptosis as analysed by DAPI staining. Investigation of the possible effectors of this process showed that cell death occurred in the presence of Bcl-2 and Bax expression, and involved a caspase-independent pathway. Confocal fluorescence microscopy indicated a major role for the lysosomal protease cathepsin B in mediating cell death. Accordingly, pre-incubation of K562 cells with the cathepsin inhibitor L-trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E-64) abolished the cytotoxic effect of CvL. Furthermore, we found upregulation of tumor necrosis factor receptor 1 (TNFR1) and down-modulation of p65 subunit of nuclear factor kappa B (NFB) expression in CvL-treated cells. These effects were accompanied by increased levels of p21 and downmodulation of pRb, suggesting that CvL is capable of cell cycle arrest. Collectively, these findings suggest that cathepsin B acts as death mediator in CvL-induced cytotoxicity possibly in a still uncharacterized connection with the membrane death receptor pathway
Resumo:
The mushrooms have been object of intense research in view of its potential raising of application in different sectors of the pharmacology and alimentary industry. Among diverse bioactive composites of polyssacharides nature that exist in the fungus the glucans are much searched. These are polymers of glucose and classified as the type of glicosidic linking [α, β]. Peroxisome proliferator-activated receptors (PPARs), ranscription factors belonging to the family of nuclear receptors that bind themselves o specific agonists, have shown their importance in controlling the inflammatory process. The aim of this study was to perform a chemical characterization of extract rom the mushroom Caripia montagnei, assess its antiinflammatory and antibacterial effect and determine if this effect occurs via PPAR. This mushroom is composed of carbohydrates (63.3±4.1%), lipids (21.4l±0.9%) and proteins (2.2± 0.3%). The aqueous solution resulting from the fractionation contained carbohydrates (98.7±3.3%) and protein (1.3±0.25%). Analyses of infrared spectrophotometry and of nuclear magnetic esonance demonstrated that the extract of mushroom C. montagnei is rich in β-glucans. In hioglycolate-induced peritonitis, the C. montagnei glucans (50 mg/kg) educed the inflammatory process in 65.5±5.2% and agonists, pharmacological igands, for PPAR: Wy-14643 (49.3±6.1%), PFOA (48.9±3.8%) and clofibrate in 45.2±3.2%. Sodium diclofenac showed a reduction of 81.65±0.6%. In the plantar edema, the glucans from C. montagnei (50 mg/kg) and L-NAME reduced the edema to a similar degree 91.4±0.3% and 92.8±0,5 %, respectively. In all the groups tested, nitric oxide (NO), an inflammation mediator, showed a significant reduction in the nitrate/nitrite levels when compared to the positive control (P<0.001). The C. montagnei glucans did not show cytotoxicity in the concentrations tested (2.5, 5.0, 10.0, 20.0 and 40.0 µg/100 µL). Antibacterial activity demonstrated that, unlike total extract, there was no inhibition of bacterial growth. The C. montagnei glucans show great potential for antiinflammatory applications. This effect suggests that it is mediated by PPAR activation and by COX and iNOS inhibition
Resumo:
The Brazil is the third largest producer of cashew nuts in the world. Despite the social and economic importance of the cashew nut, its production is still carried out artisanally. One of the main problems encountered in the cashew production chain are the conditions under which the roasting of the nut occurs to obtain the kernel from the shell. In the present study was conducted a biomonitoring of the genotoxic and cytotoxicity effects associated with the elements from the cashew nut roasting in João Câmara - RN, semi-arid region of Brazil. To assess the genotoxic was used the bioassay of micronucleus (MN) in Tradescantia pallida. In addition, it was performed a comparative between the Tradescantia pallida and KU-20 and other biomarkers of DNA damage, such as the nucleoplasmic bridges (NBP) and nuclear fragments (NF) were quantified. The levels of particulate matter (PM1.0, PM2.5, PM10) and black carbon (BC) were also measured and the inorganic chemical composition of the PM2.5 collected was determined using X-ray fluorescence spectrometry analysis and the assessment of the cytotoxicity by MTT assay and exclusion method by trypan blue. . For this purpose, were chosen: the Amarelão community where the roasting occurs and the Santa Luzia farm an area without influence of this process. The mean value of PM2.5 (Jan 2124.2 μg/m3; May 1022.2 μg/m3; Sep 1291.9 μg/m3) and BC (Jan 363.6 μg/m3; May 70.0 μg/m3; Sep 69.4 μg/m3) as well as the concentration of the elements Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br and Pb obtained at Amarelão was significantly higher than at Santa Luzia farm. The genotoxicity tests with T. pallida indicated a significant increase in the number of MN, NBP and NF and it was found a negative correlation between the frequency of these biomarkers and the rainfall. The concentrations of 200 μg/mL and 400 μg/mL of PM2.5 were cytotoxic to MRC-5 cells. All together, the results indicated genotoxicity and citotoxicity for the community of Amarelão, and the high rates of PM2.5 considered a potential contributor to this effect, mainly by the high presence of transition metals, especially Fe, Ni, Cu, Cr and Zn, these elements have the potential to cause DNA damage. Other nuclear alterations, such as the NPBs and NFs may be used as effective biomarkers of DNA damage in tetrads of Tradescantia pallida. The results of this study enabled the identification of a serious occupational problem. Accordingly, preventative measures and better practices should be adopted to improve both the activity and the quality of life of the population. These measures are of fundamental importance for the sustainable development of this activity.
Resumo:
Human multipotent mesenchymal stromal cells (MSCs), also known as mesenchymal stem cells, have become an important and attractive therapeutic tool since they are easily isolated and cultured, have in vitro expansion potential, substantial plasticity and secrete bioactive molecules that exert trophic effects. The human umbilical cord as a cell source for cell therapy will help to avoid several ethical, political, religious and technical issues. One of the main issues with SC lines from different sources, mainly those of embryonic origin, is the possibility of chromosomal alterations and genomic instability during in vitro expansion. Cells isolated from one umbilical cord exhibited a rare balanced paracentric inversion, likely a cytogenetic constitutional alteration, karyotype: 46,XY,inv(3)(p13p25~26). Important genes related to cancer predisposition and others involved in DNA repair are located in 3p25~26. Titanium is an excellent biomaterial for bone-implant integration; however, the use can result in the generation of particulate debris that can accumulate in the tissues adjacent to the prosthesis, in the local bone marrow, in the lymph nodes, liver and spleen. Subsequently may elicit important biological responses that aren´t well studied. In this work, we have studied the genetic stability of MSC isolated from the umbilical cord vein during in vitro expansion, after the cryopreservation, and under different concentrations and time of exposition to titanium microparticles. Cells were isolated, in vitro expanded, demonstrated capacity for osteogenic, adipogenic and chondrogenic differentiation and were evaluated using flow cytometry, so they met the minimum requirements for characterization as MSCs. The cells were expanded under different concentrations and time of exposition to titanium microparticles. The genetic stability of MSCs was assessed by cytogenetic analysis, fluorescence in situ hybridization (FISH) and analysis of micronucleus and other nuclear alterations (CBMN). The cells were able to internalize the titanium microparticles, but MSCs preserve their morphology, differentiation capacity and surface marker expression profiles. Furthermore, there was an increase in the genomic instability after long time of in vitro expansion, and this instability was greater when cells were exposed to high doses of titanium microparticles that induced oxidative stress. It is necessary always assess the risks/ benefits of using titanium in tissue therapy involving MSCs, considering the biosafety of the use of bone regeneration using titanium and MSCs. Even without using titanium, it is important that the therapeutic use of such cells is based on analyzes that ensure quality, security and cellular stability, with the standardization of quality control programs appropriate. In conclusion, it is suggested that cytogenetic analysis, FISH analysis and the micronucleus and other nuclear alterations are carried out in CTMH before implanting in a patient
Resumo:
Steel is an alloy EUROFER promising for use in nuclear reactors, or in applications where the material is subjected to temperatures up to 550 ° C due to their lower creep resistance under. One way to increase this property, so that the steel work at higher temperatures it is necessary to prevent sliding of its grain boundaries. Factors that influence this slip contours are the morphology of the grains, the angle and speed of the grain boundaries. This speed can be decreased in the presence of a dispersed phase in the material, provided it is fine and homogeneously distributed. In this context, this paper presents the development of a new material metal matrix composite (MMC) which has as starting materials as stainless steel EUROFER 97, and two different kinds of tantalum carbide - TaC, one with average crystallite sizes 13.78 nm synthesized in UFRN and another with 40.66 nm supplied by Aldrich. In order to improve the mechanical properties of metal matrix was added by powder metallurgy, nano-sized particles of the two types of TaC. This paper discusses the effect of dispersion of carbides in the microstructure of sintered parts. Pure steel powders with the addition of 3% TaC UFRN and 3% TaC commercial respectively, were ground in grinding times following: a) 5 hours in the planetary mill for all post b) 8 hours of grinding in the mill Planetary only for steel TaC powders of commercial and c) 24 hours in the conventional ball mill mixing the pure steel milled for 5 hours in the planetary mill with 3% TaC commercial. Each of the resulting particulate samples were cold compacted under a uniaxial pressure of 600MPa, on a cylindrical matrix of 5 mm diameter. Subsequently, the compressed were sintered in a vacuum furnace at temperatures of 1150 to 1250 ° C with an increment of 20 ° C and 10 ° C per minute and maintained at these isotherms for 30, 60 and 120 minutes and cooled to room temperature. The distribution, size and dispersion of steel and composite particles were determined by x-ray diffraction, scanning electron microscopy followed by chemical analysis (EDS). The structures of the sintered bodies were observed by optical microscopy and scanning electron accompanied by EDS beyond the x-ray diffraction. Initial studies sintering the obtained steel EUROFER 97 a positive reply in relation to improvement of the mechanical properties independent of the processing, because it is obtained with sintered microhardness values close to and even greater than 100% of the value obtained for the HV 333.2 pure steel as received in the form of a bar
Resumo:
The heat transfer between plasma and a solid occurs mostly due the radiation and the collision of the particles on the material surface, heating the material from the surface to the bulk. The thermal gradient inside the sample depends of the rate of particles collisions and thermal conductivity of the solid. In order to study that effect, samples of AISI M35 steel, with 9,5 mm X 3,0 mm (diameter X thickness) were quenched in resistive furnace and tempereds in plasma using the plane configuration and hollow cathode, working with pressures of 4 and 10 mbar respectively. Analyzing the samples microstructure and measuring the hardness along the transversal profile, it was possible to associate the tempered temperature evaluating indirectly the thermal profile. This relation was obtained by microstructural analyzes and through the hardness curve x tempered sample temperature in resistive furnace, using temperatures of 500, 550, 600, 650 and 700°C. The microstructural characterization of the samples was obtained by the scanning electron microscopy, optic microscopy and X-ray diffraction. It was verified that all samples treated in plasma presented a superficial layer, denominated affected shelling zone, wich was not present in the samples treated in resistive furnace. Moreover, the samples that presented larger thermal gradient were treated in hollow cathode with pressure of 4 mbar
Resumo:
The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And the elements of this space are always more than suffering direct or indirect influences as the flow in the port is expanded. Therefore, this region became subject to the accidental spillage of oil, because it presents a heavy traffic of ships of various sizes that can run aground or collide with oil causing accidental events. The study of geomorphological and sedimentological compositions of seafloor becomes important as more is known about the relationships between these parameters and associated fauna, and can identify their preferred habitats. The database background, acoustically collected along the proposed study area, is a wealth of information, which were duly examined, cataloged and made available. Such information can serve as an important tool, providing a geomorphological survey of the sedimentary area studied, and come to subsidize, in a flexible, future decision making. With the study area Port of Cabedelo, Paraíba - Brazil, this research aimed to evaluate the influence of the tidal surface and background in modeling the seabed, including the acquisition of information about the location of submerged rocky bodies and the depth of these bodies may turn out to be natural traps for the trapping of oil in case of leaks, and obtain the relationship between types of bed and the hydrodynamic conditions present in the region. In this context, for this study were collected bathymetric data (depth) and physical oceanographic (height of water column, water temperature, intensity and direction of currents, waves and turbidity), meteorological (rainfall, air temperature, humidity, winds and barometric pressure) of the access channel to the Port of Cabedelo / PB and its basin evolution (where the cruise ships dock), and includes tools of remote sensing (Landsat 7 ETM +, 2001), so that images and the results are integrated into Geographic Information Systems and used in the elaboration of measures aimed at environmental protection areas under the influence of this scale facilities, serving as a grant to prepare a contingency plan in case of oil spills in the region. The main findings highlight the techniques of using hydroacoustic data acquisition together bathymetric surveys of high and low frequency. From there, five were prepared in bathymetric pattern of Directorate of Hydrography and Navigation - DHN, with the depth in meters, on a scale of 1:2500 (Channel and Basin Evolution of Access to Port of Cabedelo), where there is a large extent possible beachrocks that hinder the movement of vessels in the port area, which can cause collisions, running aground and leaking oil. From the scatter diagram of the vectors of currents, it can be seen as the tidal stream and undergoes a channeling effect caused by the bidirectional effect of the tide (ebb and flood) in the basin of the Port of Cabedelo evolution in NW-direction SE and the highest speed of the currents occurs at low tide. The characterization weather for the period from 28/02 to 04/07/2010 values was within the expected average for the region of study. The multidisciplinary integration of products (digital maps and remote sensing images), proved to be efficient for the characterization of underwater geomorphological study area, reaching the aim to discriminate and enhance submerged structures, previously not visible in the images
Resumo:
This project describes a methodology optimization that would allow for a more efficient microwave assisted digestion process for petroleum samples. With the possible chance to vary various factors at once to see if any one factor was significant enough in the answers, experimental planning was used. Microwave assisted digestion allows, through the application of potency, an increasing number of collisions between the HNO3 and H2O2 molecules, favoring sample opening for complex matrixes. For this, a 24 factorial experimental planning was used, varying potency, time and the volumes for HNO3 65% and H2O2 30%. To achieve the desired answers, several elements were monitored (C, Cu, Cr, Fe, Ni, Zn and V) through Inductively coupled plasma atomic emission spectroscopy (ICP-OES). With this initial study it was noticed that the HNO3 was not a significant factor for any of the statistical studies for any of the analytes and the other 3 factors and their interactions showed statistical significance. A Box Behnken experimental planning was used taking in consideration 3 factors: H2O2 volume, time (min) and Potency (W), Nitric Acid kept at 4mL for a mass of 0,1g of petroleum. The results were extremely satisfying showing higher efficiency in the digestion process and taking in a responsibility between the answers for each analyte and the carbon monitoring was achieved in the following conditions: 7mL of H2O2, 700 Watts of potency and a reaction time of 7 minutes with 4mL de HNO3 for a mass of 0,1g of petroleum. The optimized digestion process was applied to four different petroleum samples and the analytes determined by ICP-OES