Eudice vilela - Academia.edu (original) (raw)

Papers by Eudice vilela

Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP, 1996

Nowadays monitoring chromosome alterations in perip heral blood lymphocytes have been used to acc... more Nowadays monitoring chromosome alterations in perip heral blood lymphocytes have been used to access th radiation absorbed dose in individuals exposed acci dental or occupationally to gamma radiation. Howeve r th re are not many studies based on the effects of mixed f eld neutron-gamma. The radiobiology of neutrons h a great importance because in nuclear factories worldwide t here are several hundred thousand individuals monit ored as potentially receiving doses of neutron. In this pap er it was observed the frequencies of unstable chro mos me alterations induced by a gamma-neutron mixed field. B ood was obtained from one healthy donor and expo sed to mixed field neutron-gamma sources AmBe (20 Ci) at the Neutron Calibration Laboratory (NCL – CRCN/NE – PE – Brazil). The chromosomes were observ ed at metaphase, following colcemid accumulation and 1000 well-spread metaphases were analyzed for t he presence of chromosome alterations by two experi enced scorers. The results suggest that ...

Editora Livraria da Fisica: Sao Paulo, Dec 17, 2014

Metals and Materials International, 2021

Al–5Ti–1B grain refiner was successfully prepared with the reaction of Ti chips produced during m... more Al–5Ti–1B grain refiner was successfully prepared with the reaction of Ti chips produced during machining and KBF4 in pure aluminum melt. In order to illustrate the reaction mechanism of Ti chips, the effect of different feeding ways and reaction times of Ti chips on microstructure and refining performance of Al–5Ti–1B was systematically investigated by optical microscope, scanning electron microscopy and X-ray diffractometer. The results show that, in three feeding ways, including adding Ti chips firstly, adding KBF4 firstly and adding both Ti chips and KBF4 in the form of prefabricated blocks, the best refining performance of Al–5Ti–1B is the feeding way of using the prefabricated block. TiB2 and TiAl3 as effective heterogeneous nuclei are formed simultaneously around the Ti chips. The average grain size of pure aluminum is refined to about 206.80 μm. The reaction time mainly affects the dissolution process of Ti chips and the average size of TiAl3. With the reaction time from 60 min to 90 min and then to 120 min, the average size of TiAl3 increases from 10.74 μm to 14.30 μm and then to 15.39 μm. During the dissolution process, Ti chips undergo a transition from a thermal isolation layer to a supersaturated zone of Ti atoms. Based on the analysis of the dissolution process of Ti chips, the dissolution model is proposed. Al–5Ti–1B has the best refining performance at 90 min of the reaction time, which can refine pure aluminum to about 223.65 μm.

Wavelet transform have a wide area of application in many scientific areas, for example signal pr... more Wavelet transform have a wide area of application in many scientific areas, for example signal processing, image compression [6] or data mining [4] [5]. Present requirements demand preforming large amount of calculations in the minimum time. For that reason the goal of this paper is to present an approach that will fulfill mentioned requirements, by adapting algorithms for signal processing to GPU demand. The article analyzes potential benefits of usage of the implementation of lattice structure on Graphics Processing Unit (GPU) and compares obtained results with the implementation on Central Processing Unit (CPU).

Among the various diseases that affect humanity, cancer is one of the most difficult diseases to ... more Among the various diseases that affect humanity, cancer is one of the most difficult diseases to be treated, being the second leading cause of worldwide death. Therefore, new forms of treatment are being studied aiming to improve the survival conditions of cancer bearer, or even taking them to cure. A new form of treatment that is receiving prominence is Boron Neutron Capture Therapy (BNCT). The BNCT is a binary treatment that consists in the administration of compounds containing the 10B nuclid with subsequent irradiation of epithermal neutrons in the tumor region. The BNCT principle was first proposed in 1936, but it was only between 1951 and 1961 that the therapy was tested on human patients. The first tests with sodium tetraborate did not obtain satisfactory results and for this reason the therapy was disregarded for the cancer treatment. In the 1990s, new tests with the compounds sodium borocaptate (BSH-Na 2 B 12 H 11 SH) and borophenylalanine (BPA) have shown motivating results in clinical trials, and because of these efforts, more efficient compounds have been produced for BNCT. This article describes the basic principles of BNCT, historical and prospects for research in the Brazil and the World.

This report describes the methodology of the 1998 National Travel Survey (NTS) in the UK. The NTS... more This report describes the methodology of the 1998 National Travel Survey (NTS) in the UK. The NTS provides regular up-to-date data on personal travel, and monitors changes in travel behaviour over time. The Department of the Environment, Transport and the Regions (DETR) publishes the NTS results, the Transport Research Laboratory (TRL) views the NTS as one of its major data sources, and NTS data sets are stored in the Data Archive at the University of Essex. The report is intended to be a working reference manual, and describes the NTS sample design, fieldwork methods, data acquisition, and data file production. The NTS uses two methods to collect data: (1) face-to-face interviewing conducted using computer-assisted personal interviewing (CAPI); and (2) the keeping of seven-day travel diaries. The NTS is based on a random sample of private households, to each of which a letter explaining the NTS is sent before the interviewers first call. In 1998, a 65% response was achieved. The tr...

Um acelerador ciclotron em funcionamento nas instalacoes da C omissao Nacional de Energia Nuclear... more Um acelerador ciclotron em funcionamento nas instalacoes da C omissao Nacional de Energia Nuclear e capaz de acelerar protons ate 18 MeV e deuterons ate 9 MeV. Este acelerador e dotado de canais utilizados para a producao de radiofarmacos e de um canal experimental voltado a pesquisa. Foi de interesse desse trabalho o estudo da viabilidade de implementacao do feixe neutronico a partir desse canal experimental, visto que demais fontes geradoras de neutrons nao sao capazes de fornecer um fluxo continuo e uniforme de neutrons. Logo foi realizado uma simulacao computacional com o codigo GEANT4 versao 10.0.1.p03 utilizando como dados caracteristicas desse acelerador; feixe primario de protons, energia em MeV e adotado como alvo o Berilio-9, o qual possui uma espessura de 2,5 mm. Os neutrons gerados foram medidos a uma distância de 50 cm e sob os ângulos de 0o, 15o, 30o, 45o, 60o, 70o e 90o em relacao ao feixe incidente. O exemplo foi baseado em estudos experimentais e validado atraves do...

Journal of Physics: Conference Series, 2021

Many organizations are moving toward utilizing information system to enhance eficiency in everyda... more Many organizations are moving toward utilizing information system to enhance eficiency in everyday task. Although the influence of facilitating condition are important to the success of information system implementation, the literature lacks empirical research on tthe relationship between facilitating condition and continuance intention in private higher leaning institution. In this article, the researchers introduce a simple model based on information systems (IS) and user behavior literature to examine the effect of facilitating condition on the intention to continue using e-campus. A paper-and-pencil self-administered questionnaire survey with 500 users of Malaysian private higher learning institution is carried out to evaluate the proposed model. The result proves that facilitating condition have a significant effect on e-campus continuance intention. Important practical contributions are further discussed in the paper.

Usually, medulloblastoma is treated with two lateral opposed fields in the brain and a posterior ... more Usually, medulloblastoma is treated with two lateral opposed fields in the brain and a posterior field along the spinal cord and there are several techniques available for the administration of craniospinal radiotherapy (CSRT). A common criticism is that overlap may occur at the match-line junction of the three fields, resulting in an increased risk of late effects in surrounding critical organs. Improved radiotherapy techniques in CSRT strive to reduce risks of late morbidity. The aim of this study is evaluate the delivered dose to cervical spinal cord and surrounding critical organs from two different techniques for meduloblastoma therapy in a radiotherapy centre in Recife, Brazil. For this, the adult anthropomorphic phantom ALDERSON was planned on half-beam block and angled fields techniques and it was irradiated 5 times in each technique. Thermoluminescent detectors were used to perform dosimetric measurements during treatment with 6 MV photon fields. For an applied dose of 1.5G...

Scientia Plena, 2011

Historically, cytogenetic biodosimetry assays have been based on quantifying asymmetrical chromos... more Historically, cytogenetic biodosimetry assays have been based on quantifying asymmetrical chromosome alterations in mytogen-stimulated T-lymphocytes in their first mitosis after radiation exposure. Increased levels of chromosome damage are a sensitive indicator of radiation exposure and they are routinely exploited for assessing radiation absorbed dose after accidental or occupational exposure. However there are few curves for neutron gamma mixed field available in the world, which impairs the cytogenetic studies of changes in nuclear disasters involving such radiation. In this paper the dose–response curve was measured for the induction of chromosomal alterations in peripheral blood lymphocytes after chronic exposure in vitro to neutron-gamma mixes field. Blood was obtained from one healthy donor and exposed to two neutron-gamma mixed fields from sources 241AmBe at the Neutron Calibration Laboratory (NCL – CRCN/NE – PE – Brazil). The evaluated absorbed doses covered the range 0.2-...

Occupational exposure to ionizing radiation can occur due to various human activities, such as ex... more Occupational exposure to ionizing radiation can occur due to various human activities, such as exposure during different stages of the nuclear fuel cycle, medical applications, research and all occupations that involve handling with radionuclides. This work aims to characterize extremity dosemeters based on LiF: Mg, Ti (TLD-100) for use in nuclear medicine. For this, we used the dosimetric system EXT-RAD XD-100, associated with an the adjustable ring to the finger of workers. The dosimeters were irradiated on a PMMA phantom finger and standard radiation beams using a source of 137 Cs. The calibration of the dosimeters was carried in terms of Hp (0.07). In order to analyze the performance of the dosimetric system used, tests were made for the individual sensitivity, batch homogeneity, reproducibility, beta and photon energy response and angular response, according to the recommendations of the ISO 12794. The batch of dosimeters used in this study showed a value of homogeneity better than 6.9% and reproducibility better than 4.8%. The study of angular response of the dosimeters showed variation of the response less than 15%. The energy response test showed the variation of TL response below 50% in the energy range considered. Considering the results, we can conclude that the EXT-RAD dosimetric system meets the necessary requirements for application in extremity monitoring of individuals occupationally exposed in nuclear medicine.

2017 IEEE International Conference on Information and Automation (ICIA), 2017

FH (frequency hopping) technique is widely used in underwater acoustic communication due to its g... more FH (frequency hopping) technique is widely used in underwater acoustic communication due to its good performance on anti-interference and anti-fading. In addition, communication might encounter intentionally destruction such as jamming. So it is necessary to make an effect evaluation on FH communication under jamming. Firstly, FH communication system with three typical jamming styles including partial band noise jamming, multi-tone jamming and pulse jamming. And a new jamming method called multi-tone hopping jamming against FH communication system with fixed frequency suppression is proposed. Their interference effects are analyzed. As a result, the optimal jamming styles in the specific environment are recommended. Which may provide guidance to jamming pattern selection for the FH communication system in practices.

Journal of Nanoscience and Nanotechnology, 2012

This work was developed with an aqueous suspension of maghemite nanoparticles and colloidal emuls... more This work was developed with an aqueous suspension of maghemite nanoparticles and colloidal emulsions with nanoparticles of magnetite. The nanoparticles were synthesized by co-precipitation method. The first was the magnetic emulsion nanoparticles of maghemite dispersed in the aqueous extract obtained from the leaf embauba (Cecropia Obtusifolia), whose tree is native to Central and South America. Thereby achieving the magnetic fluid extract embauba stabilized with ionic buffer solution pH 7.4. A second emulsion was prepared with colloidal magnetite nanoparticles with surfaces previously coated with oleic acid as a means of dispersing and using the oil extracted from in nature seed Andiroba (Carapa Guianensis), tree of the Brazilian Amazon. These new magnetic fluids the nanoparticles were characterized by Photoacoustic spectroscopy (PAS) to determine the coating layer of molecules on the surfaces of nanoparticles. In aqueous ionic magnetic fluid Cecropia Obtusifolia (MFCO) chlorogenic acid contributes to the electron density in the presence of four groups alcohols, a ketone group and a carboxylic group. In magnetic fluid-based oil andiroba MFAD PAS spectra show that oleic acid molecules are tightly linked on the surface of the nanoparticles.

Applied Radiation and Isotopes, 2012

In the present work, we utilized the BSS system with TLD-600 and TLD-700 to measure the neutron s... more In the present work, we utilized the BSS system with TLD-600 and TLD-700 to measure the neutron spectra around the GE-PETtrace 8 cyclotron of the Development Centre of Nuclear Technology (CDTN/CNEN) in Belo Horizonte, Brazil. The cyclotron is capable of accelerating protons up to 16.5 MeV, to production of fluorine-18. Four points inside the bunker of the cyclotron were studied. Two points in front of the primary radiation beam and other two opposed to the primary radiation beam. The measurements were unfolded with the BUMS and the NSDUAZ computer codes. The dosimetric quantities obtained were in agreement with the other published data and were coherent with the expected from theoretical estimates obtained from source term informed by the manufacturer of the cyclotron.

Revista Virtual de Química, Feb 25, 2021

AIP Conference Proceedings

The crews of present-day jet aircrafts are a significant occupationally exposed group, receiving ... more The crews of present-day jet aircrafts are a significant occupationally exposed group, receiving relatively high effective doses from exposure to cosmic radiation, with the possibility of higher effective doses if the cruising altitudes of future aircrafts increase. To assess effective doses from exposure to cosmic radiation, the MAX (Male Adult voXel) phantom has been coupled with the GEANT4 Monte Carlo