Abstract: Over the last decades there was an increasing interest in using magnesium alloys for medical applications due to their biodegradability in the human body, providing a temporary mechanical support and corroding completely after the tissue healing. Although magnesium is a non-toxic element, it is of great importance to evaluate the element concentration, as well as the impurities present in both, pure magnesium and magnesium alloys, as the AZ31. The purpose of this study was to analyze the element composition of these materials using the method of neutron activation analysis (NAA). Standard Reference Materials (SRMs) acquired from National Institute of Standards and Technology (NIST) were analyzed for analytical quality control. Short and long term irradiations were carried out at the IEA-R1 nuclear research reactor and gamma-ray activities induced to the samples and element standard were measured using HPGe detector coupled to a Digital Spectrum Analyzer. The radioisotopes were identified by gamma ray energies and half-life. Concentrations of the elements As, Cr, Cd, Co, Fe, In, La, Mg, Mn, Mo, Na, Sb, V, W and Zn were determined in pure magnesium sample and the Al, As, La, Mg, Mn, Na, Sb and Zn in the AZ31 alloy, calculated by comparative method. The SRMs were analyzed by applying the same experimental conditions used for magnesium-based materials and their results presented good accuracy and precision. Thus, from the measurements obtained in this study it can be concluded that NAA is a suitable method for element determinations in magnesium-based materials providing reliable results.

Palavras-Chave: biological materials; gamma radiation; high-purity ge detectors; impurities; magnesium alloys; quality control

SILVA, C.A.J.; BRAGUIN, L.N.M.; ROSSI, J.L.; COSTA, I.; SAIKI, M. Determination of chemical elements in magnesium-based materials by neutron activation analysis. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-16, 2021. DOI: 10.15392/bjrs.v9i1A.1584. Disponível em: http://repositorio.ipen.br/handle/123456789/32149. Acesso em: $DATA.

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Abstract: Dianthus chinensis flowers are widely used in culinary preparations and are appreciated because of its bioactive compounds. It is a perishable food that should be grown without the use of pesticides. In this context, food irradiation is a process that has proven to be an efficient tool in preserving and extending the perishable product shelf life without changing the temperature or leaving residues. The purpose of this study was to evaluate carotenoids in D. chinensis flowers submitted to gamma irradiation and electron beam doses of 0.5, 0.8, and 1.0 kGy. High-performance liquid chromatography for carotenoid determination was used. In the edible flower analyzed was found carotenoid lutein (4.02 to 7.52 mg/ 100 g). The lutein was higher for irradiated samples, especially those treated with 0.8 and 1.0 kGy in both irradiation technology. In conclusion, the lutein amount in the chinese pink enhances as the dose increases, and the applied irradiation treatments represent a feasible technology to preserve the nutritional quality of edible flower petals as well as attend to food safety requirements.

Palavras-Chave: carotenoids; cobalt 60; flowers; food processing; gamma radiation; high-performance liquid chromatography

KOIKE, A.C.R.; ARAUJO, E.S.; NEGRAO, B.G.; ALMEIDA-MURADIAN, L.B.; VILLAVICENCIO, A.L.C.H. Analysis of carotenoids in edible flowers of Dianthus chinensis processed by ionizing radiation. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1577. Disponível em: http://repositorio.ipen.br/handle/123456789/32147. Acesso em: $DATA.

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Abstract: There are serious evidences that justify the search for treatment technologies or processes combination for the improvement of decomposition for dozens of pharmaceuticals in wastewaters. Electron beam irradiation may play an important role in this scenario and relatively low doses have been reported for such purposes. The aim of the present study was to evaluate the toxic response of the crustacean Daphnia similis exposed to individual and combined pharmaceuticals, before and after electron beam irradiation treatment. Several experimental trials of an acute immobilization test were performed with a mixture of pharmaceuticals composed of fluoxetine hydrochloride (Prozac®), and propranolol. Single pharmaceuticals were first tested separately. Toxicity of binary mixture was then assessed using five concentrations and five percentages of each substance in the mixture (0, 25, 50, 75, and 100%). Acute EC50% values ranged from 5.0 to 7.4 for fluoxetine and from 11.3 to 13.7 for propranolol. In mixture, values ranged from 6.4 to 9.8. Fluoxetine was more toxic than propranolol for D.similis. The different pharmaceuticals concentrations employed in a mixture showed no difference in toxicity values. When electron beam irradiation was applied, approximately 80% of acute effects were reduced at 5 kGy, and the mixture containing a higher percentage of fluoxetine, also showed a greater reduction of toxicity.

Palavras-Chave: ecological concentration; crustaceans; environmental effects; environmental protection; waste water; irradiation; toxicity

BOIANI, NATHALIA F.; GARCIA, VANESSA S.G.; BORRELY, SUELI I. Electron beam irradiation of combined pharmaceuticals: propranonol and fluoxetine and related ecotoxicity. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-12, 2021. DOI: 10.15392/bjrs.v9i1A.1575. Disponível em: http://repositorio.ipen.br/handle/123456789/32145. Acesso em: $DATA.

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Abstract: If in the 19th century scientific knowledge moved from a generalist perspective to a growing specialization, in recent decades, problems that transcend disciplinary and political boundaries have required solutions based on interdisciplinary research and global actions, which led to the establishment of the Sustainable Development Goals (SDGs). Viewing from the latter perspective, the study of ecosystem services has converged on a fast-growing, transdisciplinary area of knowledge, at the same time that the advances in the nuclear field have enabled applications in industry, health, agriculture and the environment. Considering the development of these two areas of knowledge, the objective of this study is to evaluate the correlation between Ecosystem Services (ES) and Nuclear Science and Technology (NST), by means of category building and content analysis applied to articles compiled from Web of Science. From 1980 to June 2020, 27,301 records (articles and reviews) were listed for the term “Ecosystem Service*”. When refining the result with the application of descriptors related to the nuclear field, correspondences were found for “Uranium”=14; “Nuclear Power”=6; “Nuclear Energy”=3; “Nuclear Technology*”=1; “Nuclear Fuel*”=1; “Nuclear Material*”=1; “Radiation”=7; “Isotope*”=188, totalizing 221 correspondences. On the other hand, 9,949 records were obtained for the same time interval, when using the descriptors for the nuclear field, plus the terms “Nature” or “Ecosystem*” or “Environment”. Despite attesting that NST truly converges on ES, this correlation needs to be made more explicit in ES studies, in order to expand the perspectives for the conservation, preservation and recovery of the ecosystem services and their contribution to human well-being.

Palavras-Chave: sustainable development; ecology; ecosystems; environment; nuclear energy; technology utilization

RODRIGUES, E.A.; AQUINO, A.R.; CARVALHO, A.R. Convergence between the study of ecosystem services and nuclear technology: a necessary approach. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i1A.1567. Disponível em: http://repositorio.ipen.br/handle/123456789/32143. Acesso em: $DATA.

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Abstract: Cervical cancer (CC) is a worldwide public health problem and stands out in the North of the State of Tocantins as the leading cause of the cancer death. It is the fourth most common type cancer in women, with an estimate of 570 thousand new cases and 311 thousand deaths from this disease worldwide in 2018. The lack of effective screening increases the incidence of late diagnosis weighing on the budgets of developing countries, which are the most affected. The objective of this work is to describe the epidemiological profile of the woman treated which a diagnosis of cervical cancer in Northern of Tocantins. Materials and methods: It is a descriptive, retrospective, quantitative-interpretive study with analysis of data collected from 2000 to 2015 by the Health Information System of the Hospital Cancer Registry (SIS-RHC) linked to the Regional Hospital of Araguaína (HRA). The data were tabulated in spreadsheets for analysis of the variables evaluated. Results: 2.664 women with cervical cancer treated at the HRA were analyzed during this period. Within the existing stages, the stages 0, I and II were considered “early staging”, and stages III and IV were considered “late staging”. Conclusions: The factors occupation, race, education and smoking were well defined in the incidence of this tumor, especially in the case of late staging. The challenges are many to obtain adequate medical assistance, mainly in the Northern Region of Tocantins and adjacent regions. The knowledge of the epidemiological profile of these women will be important for the development of new health prevention policies, improving the incidence and mortality from this tumor.

Palavras-Chave: epidemiology; neoplasms; uterus; carcinomas; statistical data; data analysis; women; patients

PINHEIRO, A.L.L.P.; COELHO, A.L.L.P.; SIMPSON, S.; SOARES, N.A.; SANTOS FILHO, W.P.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M. Clinical-epidemiological profile of women with cervical cancer in the North of the State of Tocantins: 2000 to 2015 period. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-10, 2021. DOI: 10.15392/bjrs.v9i1A.1546. Disponível em: http://repositorio.ipen.br/handle/123456789/32141. Acesso em: $DATA.

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Abstract: Gaining prominence in clinical practice, the 68Ga, positron emitter radionuclide easily obtained by 68Ge/68Ga generator elution, has shown potential and excellent quality on radiolabeling of peptide for use in positron emission tomography (PET), in particular urea-based inhibitor peptides, directed to the prostate-specific membrane receptor (PSMA). Previous studies with the PSMA linked to the chelator HBED-CC (PSMA-11) radiolabeled with 68Ga showed high contrast PET/CT images to evaluate recurrence and metastasis of prostate cancer, becoming an important imaging agent in the clinical routine. This work intended to evaluate the influence of the quality of the 68Ge/68Ga generator eluate in direct labelling of PSMA-11 with 68Ga, assisting in the development of kit for prompt radiolabeling. It was evaluated the 68GaCl3 eluate from 68Ge/68Ga non-GMP generator (manufacturer A) and 68Ge/68Ga GMP generator (manufacturer B), both commercially available. To evaluate the influence of the 68Ga eluate on radiochemical yield of the preparations, the radiochemical purity was determined by thin layer chromatography and HPLC. The radiolabeling with non-GMP generator eluate was made with and without preliminary purification of the 68 gallium chloride eluate, employing cationic purification columns. The results showed higher radiochemical yield with the 68GaCl3 eluate from the 68Ge/68Ga GMP generator, obtaining the radiolabeled product more easily and speed to clinical practice, without preliminary purification, as opposed to the use of non-GMP 68Ge/68Ga generator which required preliminary purification of the 68GaCl3 eluate to promote satisfactory radiochemical purity results.

Palavras-Chave: carcinomas; prostate; neoplasms; positron computed tomography; membrane proteins; gallium 68; germanium 68

VIVALDINI, B.F.; ARAUJO, E.B. The influence of generator eluate in radiolabeling PSMA-11 kit with 68Ga. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-9, 2021. DOI: 10.15392/bjrs.v9i1A.1541. Disponível em: http://repositorio.ipen.br/handle/123456789/32139. Acesso em: $DATA.

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Abstract: Clayey materials have been adopted in most nuclear waste producing countries as a key constituent in engineered barrier systems for final disposal facilities at all levels of radioactive wastes (LILW-SL, LILW-LL, and HLW). The following study presents a thorough characterization upon five Brazilian clay-rich deposits, mostly smectite bearing clays, aiming to evaluate their expected performance as barrier under the conditions associated to a Low and Intermediate Level Waste Repository; being the former a matter of national strategic interest. Samples coming from the Brazilian states of Paraná, Bahia, Paraíba, and Maranhão were treated and analyzed by means of X-Ray diffraction as main technique. Other techniques such as FTIR, LALLS, XRF, and SEM-EDS, were performed in order to establish the mineralogical composition, particle size distribution, and chemical composition. Moreover, several standard clay treatments over the <1 μm size fraction were carried out to reveal information regarding layer charge, major interlayer cations, unit formula and other crystal features of smectite species present in a mineralogical assembly, aiming to provide information for the construction of a molecular model over which would be realistic to simulate the diffusion of radionuclides. Results obtained on 133Cs adsorption experiments indicate that mineralogical composition would probably be the single most influential factor controlling transport capacity of positively charged radionuclides in the current setup. The composition is especially expressed in terms of smectite contents, favoring montmorillonite rich materials containing majorly Na+ as compensating cation in interlayer position. All tested samples can be considered as suitable candidates to be used in the design of final destination storage for nuclear waste. Thus, efficiency on 133Cs adsorption trials also indicate that these materials could have potential uses as sorptive matrices (Sorbents) for water treatment of radionuclide polluted waters such as TENORM waste waters. However, these trends are yet to be contrasted against hydraulic conductivity measurements and swelling pressure in order to have a more comprehensive perspective of this clayey prospects as barrier enhanced layer; aligned to the multilayer barrier system approach for nuclear waste management.

Palavras-Chave: radioactive waste storage; fourier transformation; infrared spectra; cesium 133; clays

MACHADO, G.G.; KRUPSKAYA, V.V.; ZAKUSIN, S.V.; HARADA, J.; VICENTE, R.; SOUZA, R.P.; ARAUJO, L.G.; MONTALVAN, E.T.; ESPINOSA, D.C.R.; KAHN, H.; GUILHEN, S.N. Brazilian clays for environmental solutions applied to radioactive waste management. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1A.1539. Disponível em: http://repositorio.ipen.br/handle/123456789/32137. Acesso em: $DATA.

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Abstract: The water parks located in the cities of Cambuquira, Caxambu, Conceição do Rio Verde, Lambari and Marimbeiro are part of the Water Circuit of Minas Gerais and have their mineral waters regularly consumed by the local population and tourists motivated by the medicinal use of these waters, characterized as mineral waters. Therefore, the objective of this work was to determine the inorganic chemical composition of the mineral water from these parks, analysing the elements Ag, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K. Mn, Ni, Pb, Se, Ti, V and Zn using the energy dispersive X-ray fluorescence – EDXRF. Despite the proximity to one another, each park has different chemical elements and concentrations. The elements presenting the highest concentrations were the major elements Ca, Fe, K and Mn. However, among the five water parks studied, the Water Park of Caxambu presented the highest concentrations for all the determined elements.

Palavras-Chave: x-ray fluorescence analysis; inorganic compounds; ecological concentration; elements; recreational areas; water springs; drinking water; composition

WAKASUGI, D.S.M.; DAMATTO, S.R.; MENEGHINI, A.A.; SANTOS, L.A.B.; SALVADOR, V.L.R. Inorganic chemical composition by X-ray fluorescence spectrometry of the mineral waters from the Minas Gerais Water Circuit, Brazil. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-19, 2021. DOI: 10.15392/bjrs.v9i1A.1528. Disponível em: http://repositorio.ipen.br/handle/123456789/32135. Acesso em: $DATA.

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Abstract: Phosphogypsum is a residue that has been used by the cement industry as a substitute for the natural gypsum, used as a clinker additive during the production of Portland cement. There is a potential increase in this residue consumption since large amounts of phosphogypsum are generated as outcome of the phosphate fertilizer industries. However, phosphogypsum can be considered a source of radioactive contamination due to the presence of 226Ra in its composition. Depending on the concentration of 226Ra, from the radiological protection point of view, this may cause a problem because this radionuclide and its direct decay product 222Rn along with other decay products, represent the largest fraction of radiation internal dose received by people. In order to evaluate the level of radiological risk that may be associated with the use of phosphogypsum, it is necessary to identify the concentration of 226Ra in building materials. The aim of this research is to analyze samples of phosphogypsum in relation to the concentrations of 226Ra, determined indirectly through 222Rn activity measurements. This measurement process has the advantage of being fast, convenient and relatively inexpensive when compared to traditional methods of 226Ra concentration in samples measurements. The proposed physical-mathematical model was used to establish radium concentration from radon exhalation rate from cement mortar samples. The 222Rn activity measurements were performed with a portable detector with cubic phosphate samples with 50 mm edges each placed in a closed atmosphere of the sampling chamber until secular equilibrium is achieved. Obtained concentrations of radium activity in studied samples of phosphogypsum and cement mortars were found below the limits recommended by CNEN and international regulation.

Palavras-Chave: building materials; concentration ratio; exhalation; gypsum cements; phosphates; radiation detectors; radiation protection; radioactivity; radium 226; radon 222

GERALDO, R.R.; PASCHUK, S.A.; BARRETO, R.C.; CORREA, J.N.; ZAHN, G.S.; SILVA, P.S.C. da; SILVA, A.M. da; NARLOCH, D.C.; ARAUJO, I.C. Application of a semi-empirical model for the evaluation of radium activity in phosphogypsum used as component of clinker. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i1A.1518. Disponível em: http://repositorio.ipen.br/handle/123456789/32133. Acesso em: $DATA.

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Abstract: Brachytherapy is a type of radiotherapy that uses radioactive sources (seeds, wires, among others) close to the tumor. Is important to provide a detailed description of seed dosimetry, so only the tumor will be irradiated avoiding unnecessary dose on adjacent organs and structures. To evaluate the dosimetric parameter of the anisotropy function for a new brachytherapy source, this work proposes the use of microcube TLD-100 dosimeters to find the dose rate using the AAPM Task Group 43 protocol (TG-43). The anisotropy function represents dose distribution around the source and has a major role for characterization of a new iridium source being implemented in Brazil. The value of D(r,θ) was measured using Solid Water phantoms, r value being the distance from the geometric center of the source to the position of the dosimeter on the phantom, and θ being the angle formed between the longitudinal axis of the source and the line connecting the geometric center to the TLD. Monte Carlo calculations were performed to evaluate the anisotropy function to validate the experimental measurements. For each distance value (r), an anisotropy function was plotted (1.0, 2.0, 3.0, 4.0, 5.0, and 10.0 cm). The results obtained with Monte Carlo calculations agreed ±2% with the experimental values for r greater than 3.0 cm, so these results show a good distribution of dose around the seed considering the high energy of 192-Ir (average of 380 KeV) and encapsulation thickness.

Palavras-Chave: anisotropy; brachytherapy; dose rates; dosimetry; iridium 192; monte carlo method; phantoms; radiation dose distributions; radiation source implants; sealed sources; thermoluminescent dosemeters

ABREU, R.T.; ANGELOCCI, L.V.; NOGUEIRA, B.R.; SANTOS, H.N.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M. Anisotropy function of a new 192-Ir brachytherapy source. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i1A.1506. Disponível em: http://repositorio.ipen.br/handle/123456789/32130. Acesso em: $DATA.

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Abstract: The major part of the world production of hydrogen (H2) is originated from a combination of methane steam reforming and water gas shift reaction resulting in an H2 rich mixture known as reformate gas, which contains about 1% vol (10,000 ppm) of carbon monoxide (CO). The preferential oxidation reaction of CO in H2 rich mixtures (CO PROX) has been considered a very promising process for H2 purification, reducing CO for values below 50 ppm allowing its use in PEMFC Fuel Cells. Au nanoparticles supported on TiO2 (Au/TiO2) catalysts have been shown good activity and selectivity for CO PROX reaction in the temperature range between 20 80 ºC; however, the catalytic activity strongly depends on the preparation method. Also, the addition of Cu to the Au/TiO2 catalyst could increase the activity and selectivity for CO PROX reaction. In this work, AuCu/TiO2 catalysts with composition 0.5%Au0.5%Cu/TiO2 were prepared in a single step using electron beam irradiation, where the Au3+ and Cu2+ ions were dissolved in water/2 propanol solution, the TiO2 support was dispersed and the obtained mixture was irradiated under stirring at room temperature using different dose rates (8 64 kGy s 1) and total doses (144 576 kGy). The catalysts were characterized by energy dispersive X ray analysis, X ray diffraction transmission electron microscopy, temperature programmed reduction and tested for CO PROX reaction. The best result was obtained with a catalyst prepared with a dose rate of 64 kGy s 1 and a total dose of 576 kGy showed a CO conversion of 45% and a CO2 selectivity of 30% at 150 ºC.

Palavras-Chave: absorbed radiation doses; carbon monoxide; catalysts; copper; dose rates; electron beams; gold; hydrogen; irradiation; mixtures; nanoparticles; oxidation; titanium oxides

ALENCAR, C.S.L.; PAIVA, A.R.N.; SILVA, L.G.A.; SOMESSARI, E.S.R.; VAZ, J.M.; SPINACE, E.V. AuCu/TiO2 catalysts prepared using electron beam irradiation for the preferential oxidation of carbon monoxide in hydrogen-rich mixtures. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-16, 2021. DOI: 10.15392/bjrs.v9i1A.1497. Disponível em: http://repositorio.ipen.br/handle/123456789/32128. Acesso em: $DATA.

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Abstract: Materials capable of converting ionizing radiation into light photons are called scintillators, some have specific efficiencies for certain applications and types of radiation, e.g. gamma, X-ray, alpha, beta and neutrons. CsI:Tl and NaI:Tl crystals are commonly found in the market because they have several applications, but few studies have been done on lithium doped cesium iodide crystal (CsI:Li). The lithium element, in this crystal used as a dopant, is also exploited as a converter for neutron detection, as it has a shock section of 940 barns for thermal neutrons. The study of the CsI:Li crystal is convenient considering the natural abundance of the lithium element with 7.5%, besides the interest in having a low cost national scintillator material, with an opportunity to search for the response of a detector for different types of radiation. The CsI:Li crystal was grown with molar concentration 10-4 to 10-1, using the vertical Bridgman technique. The parameters involved in the growth process were investigated. The transmittance was evaluated in the spectral region from 190 nm to 1100 nm. Luminescence emission spectra for the CsI:Li crystal were evaluated by photometric analysis of the crystal stimulated with a 137Cs (662 keV) source in front of the coupled sample at the monochromator input. The crystals showed maximum luminescence intensity at the wavelength of 420 nm. It was evaluated the response of the scintillators, when excited with gamma radiation of 241Am, 133Ba, 22Na, 137Cs, 60Co and neutron radiation from the AmBe source, with energy range of 1 MeV to 12 Mev.

Palavras-Chave: cesium 137; cesium iodides; crystal growth; doped materials; emission spectra; energy range; gamma radiation; lithium; neutron detection; optical properties; phosphors; photometry; radiation detectors

PEREIRA, M.C.C.; FILHO, T.M.; TOMAZ, L.F.; BERRETTA, J.R. Growth and optical characteristics of the CsI:Li scintillator crystal for use as radiation detector. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i1A.1478. Disponível em: http://repositorio.ipen.br/handle/123456789/32126. Acesso em: $DATA.

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Abstract: Shales are fine-grained rocks formed by clays and silt-sized particles in thin, relatively impermeable layers. They are originated from rocks that suffered weathering and erosion and their composition is quite variable. When oil production declines, interest arises to improve the understanding of the physicochemical properties of unconventional rocks, like shale. For the characterization of the shale samples of the Iraty Formation, the gamma-ray computed industrial tomography technique has been proposed to be used as an alternative to obtaining information about each element present in the mineral, the pore distribution, through the shale morphology. The tomographic results were compared with those obtained by conventional methodologies used in the petrological analysis, such as scanning electron microscopy (SEM), x-ray fluorescence, and x-ray diffraction.

Palavras-Chave: comparative evaluations; computerized tomography; gamma radiation; industrial radiography; morphology; nai detectors; petrology; reservoir rock; shales

BERNARDES, T.L.S.; AMADEU, R.A.; SANTOS, R.S.; GARCIA, R.H.L.; VELO, A.F.; CAVALLARO, F.A.; MESQUITA, C.H.; HAMADA, M.M. Petrological study of the Iraty Formation Shale Rocks from Paraná Basin, Limeira, São Paulo. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-17, 2021. DOI: 10.15392/bjrs.v9i1A.1467. Disponível em: http://repositorio.ipen.br/handle/123456789/32124. Acesso em: $DATA.

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Abstract: Cyanobacteria are an ancient and diverse group of microorganisms, considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, the input of nutrients in water by anthropogenic activities frequently provides cyanobacteria blooms associated with toxic compounds. Secondary metabolites, also called cyanotoxins, are often harmful to wild and domestic life, including humans. The first part of this review focuses on cyanobacteria and their ability to produce a variety of toxins as well as describe the Brazilian guidelines on the evaluation and management of these toxins in water quality. Then, we present a review of recent literature on the use of ionizing radiation in terms of cyanobacteria cell removal, degree of degradation of cyanotoxins in water, and reaction kinetics. In view of the exposed results, the paper concludes that ionizing radiation is an efficient and economically viable alternative for the remediation of areas contaminated by cyanobacterial blooms and cyanotoxins, especially in reservoirs intended for water treatment and supply. In addition, some suggestions are provided for further studies on the use of this technology in the treatment of drinking water.

Palavras-Chave: comparative evaluations; cyanobacteria; drinking water; electron beams; gamma radiation; inhibition; radiation doses; removal; toxins; water treatment

SILVA, T.T.; BORRELY, S.I. Use of ionizing radiation for the inhibition and removal of cyanotoxins in water: a brief review. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i1A.1457. Disponível em: http://repositorio.ipen.br/handle/123456789/32122. Acesso em: $DATA.

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Abstract: Ionizing radiation applied to agriculture has mainly benefited food production, as it reduces natural losses caused by physiological processes, as well as eliminating or reducing microorganisms, parasites and pests. In addition, this technique also allows the production of mutants with characteristics of greater productivity, precocity, smaller size, greater resistance to diseases and pests. These mutants are used to obtain new varieties of species of agronomic interest. The objective of this study was to evaluate the physic-chemical quality of the oil extracted from seeds of G. max (soybean) obtained from irradiated seeds with different doses of gamma radiation (0, 25, 50, 75 and 100 Gy of a Cobalt-60 source, type Gammacell-220 installed in CENA-USP). The physic-chemical analyzes included: AOCS Cd-3d-63, AOCS Cd-3-25 and AOCS Cd-1-25, Acids Index (I.A.), Saponification Index (I.S.), Iodide Index (I.I.), respectively. All analytical determinations were performed at least in triplicates. The values found for I.A., for I.S. and for I.I., did not differ from the oil sample obtained from soybean seeds from control subjects (without irradiation) regardless of the concentration and dose of radiation applied to the seeds. The oil analyzed did not show physical-chemical variation in comparison with the oil obtained from non-irradiated seeds, thus suggesting the absence of modifications in these parameters after the genetic improvement induced by the radiation.

Palavras-Chave: agriculture; cobalt 60; gamma radiation; glycine; irradiation; physical chemistry; radiation dose units; radiation doses; radiation effects; seeds; soybeans; toxicity

FRANCO, J.G.; SILVA, R.M.G. da; SUGUIMOTO, R.Y.; FRANCO, S.S.H.; VILLAVICENCIO, A.L.C.H.; ARTHUR, V. Glycine max oil physical-chemical quality obtained of irradiated seeds. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1450. Disponível em: http://repositorio.ipen.br/handle/123456789/32120. Acesso em: $DATA.

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Abstract: The use of irradiation process in stored grain may be the solution for the losses caused in these products by insects, as it does not induce resistance in the insects and leaves no toxic residue, and is considered an efficient and safe method of control of insects. The aim of the experiment was to determine the sterilizing dose of ionizing radiation from cobalt-60 to Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae) in peanuts irradiated in pupa stage. The experiment was conducted in the laboratory of Radiobiology and Environment of the Center for Nuclear Energy in Agriculture - CENA / USP., Piracicaba, SP, Brazil. Peanuts samples infested with pupae of A. diaperinus were utilized in the experiment that consisted of 8 treatments with 5 repetitions. Each repetition consisted of 20 pupae a total of 100 individuals per treatment. Were irradiated with doses of 0 (control), 25, 50, 75, 100, 125, 150 and 175 Gy, in a source of cobalt-60, Gammacell-220 type, with a rate dose of 381Gy / h. The experiment was conducted in a controlled temperature of 25 ± 5 ° C and relative humidity of 70 ± 5%. After of irradiation process was evaluated of the number of emerged adult insects in each repetition in the treatments. The results showed that the sterilizing dose in F1 generation was 125 Gy and the pupa lethal dose 150 Gy. The dose of 150 Gy of gamma radiation can be used as phytosanitary treatment to control of immature stages of A. diaperinus infested peanuts.

Palavras-Chave: cobalt 60; coleoptera; dose rates; gamma radiation; irradiation; lethal doses; peanuts; pupae; radiation dose units; radiation doses; sterilization

ARTHUR, P.B.; VILLAVICENCIO, A.L.C.H.; HARDER, M.N.C.; MACHI, A.R.; LEANDRO, R.S.R.; ARTHUR, V. Sterilizing of Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae) irradiated in pupa stage. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-7, 2021. DOI: 10.15392/bjrs.v9i1A.1445. Disponível em: http://repositorio.ipen.br/handle/123456789/32118. Acesso em: $DATA.

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Abstract: Brachytherapy is a modality of radiotherapy which treats tumors using ionizing radiation with sources located close to the tumor. The sources can be produced from several radionuclides in various formats, such as Iodine-125 seeds and Iridium-192 wires. In order to produce a new Iodine-125 seed in IPEN/CNEN and ensure its quality, it is essential to describe the seed dosimetry, so when applied in a treatment the lowest possible dose to neighboring healthy tissues can be reached. The report by the AAPM’s Task Group 43 U1 is a document that indicates the dosimetry procedures in brachytherapy based on physical and geometrical parameters. In this study, dose-rate constant and air-kerma strength parameters were simulated using the Monte Carlo radiation transport code MCNP4C. The air-kerma strength is obtained from an ideal modeled seed, since its actual value should be measured for seeds individually in a specialized lab with a Wide-Angle Free-Air Chamber (WAFAC). Dose-rate constant and air-kerma strength are parameters that depends on intrinsic characteristics of the source, i.e. geometry, radionuclide, encapsulation, and together they define the dose-rate to the reference point. Radial dose function describes the dose fall-off with distance from the source. This study presents the values found for these parameters with associated statistical uncertainty, and is part of a larger project that aims the full dosimetry of this new seed model, including experimental measures.

Palavras-Chave: brachytherapy; computerized simulation; dose rates; dosimetry; iodine 125; kerma; monte carlo method

PRIMO, C.O.; ANGELOCCI, L.V.; KARAM JUNIOR, D.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M. Dose-rate constant and air-kerma strength evaluation of a new 125I brachytherapy source using Monte-Carlo. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1441. Disponível em: http://repositorio.ipen.br/handle/123456789/32116. Acesso em: $DATA.

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Abstract: In southwest Amazonia, in the region of the Upper Madeira River, Rondônia, archaeological research has shown that communities with diverse cultures co-existed in the pre-colonial past (ca. 1,000 BP). Archaeological sites from this period located on river banks and islands consist of large extensions of ceramic deposits which reflect different daily activities and social positions that existed within these groups. The complexity of these societies is attested to by the diversity of both ceramic forms and iconography. In this work, 140 ceramic fragments from eight archaeological sites were studied by means of instrumental neutron activation analysis (INAA) to determine Na, K, La, Sm, Yb, Lu, U, Sc, Cr, Fe, Co, Zn, Rb, Cs, Ce, Eu, Hf, Ta and Th mass fractions, with the purpose of classifying and ordering artifacts which are related to one another in their chemical compositions. The analytical method used is adequate for this type of study because it is a semi-destructive technique with high sensitivity and precision that can determine chemical elements in trace and ultra-trace levels, essential for studying small variations in elemental concentrations. Multivariate statistical analyses were used to evaluate the dataset. Initially the mass fractions were normalized to compensate for the large difference in magnitude among elements determined in percentage and in trace level. Subsequently, the mass fraction data were interpreted through cluster analysis, discriminant analysis and a log-log scatterplot. The results showed the existence of four compositional groups, indicating different clay sources.

Palavras-Chave: archaeology, ceramics; chemical composition; clays; cluster analysis; elements; gamma spectra; multivariate analysis; neutron activation analysis; rivers; scatterplots

COSTA, A.F.; MUNITA, C.S.; ZUSE, S.; KIPNIS, R. Archaeometry and Archaeology: preliminary studies of the ceramics from archaeological sites of the upper Madeira river/Rondônia - Brazil. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-16, 2021. DOI: 10.15392/bjrs.v9i1A.1424. Disponível em: http://repositorio.ipen.br/handle/123456789/32114. Acesso em: $DATA.

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Abstract: Neutron Activation Analysis (NAA) is a well-established nondestructive analytic technique where the gamma radiation emitted by an irradiated sample is analyzed using an HPGe detector. The Neutron Activation Laboratory (LAN) of IPEN-CNEN/SP has been performing NAA analyses for over 30 years, and has plans of implementing quality control protocols to their analyses. In this sense, the environmental monitoring of the laboratories where the detectors are used has been performed for many years, in a manual way with no more than 2 measurements per day. In this work, an automated monitoring station based on a microcontroller ArduinoUNO board has been developed which comprises four thermo hygrometer sensors for monitoring different parts of the environment, plus a thermocouple for monitoring the inside of the liquid nitrogen dewar. The results obtained allow for a discussion on the performance and adequacy of the sensors.

Palavras-Chave: automation; environment; high-purity ge detectors; monitoring; neutron activation analysis; performance; sensors; thermocouples; uses

MELO, G.R.; ZAHN, G.S.; GENEZINI, F.A.; MOREIRA, E.G. Development of an environmental monitoring station for HPGe detectors. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1A.1412. Disponível em: http://repositorio.ipen.br/handle/123456789/32112. Acesso em: $DATA.

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Abstract: In this work the reproducibility of the efficiency of different HPGe detectors was analyzed under a series of different conditions. The detectors studied were plugged either to a regular analogical amplifier or to a digital signal processing (DSP) device, to evaluate the possible differences between either setup. Detectors were inspected by performing a long series of sequential measurements with standard calibration sources and comparing the standard deviation of the number of counts per second in each series to the uncertainty of the individual measurements. Detectors were also subjected to distinct count rates, to verify the possible experimental issues associated with this parameter. The results allow a discussion on the stability of the detectors’ efficiencies over a few days, the possible dependence with the count rate, and the estimation of the uncertainty related to the efficiency variation.

Palavras-Chave: calibration standards; comparative evaluations; counting ratemeters; data covariances; efficiency; high-purity ge detectors; stability

ZAHN, G.S.; GENEZINI, F.A. Efficiency stability of HPGe detectors under distinct count rates. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-8, 2021. DOI: 10.15392/bjrs.v9i1A.1410. Disponível em: http://repositorio.ipen.br/handle/123456789/32110. Acesso em: $DATA.

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Abstract: Tree barks have proven to be a valuable source of information on air quality. Nowadays, studies with this biomonitor are constantly being developed. However, data of several factors that affect the accumulation of the pollutants in the barks, such as bark porosity, duration of the deposition on the bark and dispersion or variability of pollutants in a defined area, are scarce in the literature. The aim of this study was to evaluate the spatial variability of chemical elements concentrations accumulated on Sibipiruna (Cenostigna pluviosarum) barks in order to examine their aerial dispersion in two small urban areas of the Metropolitan Area of São Paulo. The neutron activation analysis (NAA) applied in the analyses consisted of irradiation the aliquots of the sample together the synthetic element standards at the IEA-R1 nuclear reactor. Concentrations of the As, Br, Ca, Co, Cr, Cs, Fe, K, La, Mn, Rb, Sb, Sc, V and Zn were determined in tree barks using short and long irradiations. Results obtained in the analyses of the tree bark samples indicated that the variability of element concentrations depends on the element, study area and numbers of trees. The variability of element concentrations in general was higher for elements presenting low concentrations. Quality control of the analytical results was evaluated by the analysis of INCT-MPH-2 Mixed Polish Herbs Certified Reference Material and these results presented good accuracy with values of standardized difference or |ζ score| ≤ 2, indicating that the procedure of NAA applied is suitable for the analyses.

Palavras-Chave: air pollution monitoring; bark; biological markers; concentration ratio; ecological concentration; elements; neutron activation analysis; trees

ISHIMARU, G.; SANTOS, E.C.; SAIKI, M. Evaluation of the spatial variability of the elements in tree barks used as biomonitors of atmospheric pollution. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-13, 2021. DOI: 10.15392/bjrs.v9i1A.1386. Disponível em: http://repositorio.ipen.br/handle/123456789/32108. Acesso em: $DATA.

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Abstract: Prostate cancer is the most common chronic disease among men in most parts of the world. According to the National Cancer Institute (INCA) in Brazil in 2018, 68,000 new cases were registered. Among the main treatments the radiotherapy has been shown to be effective in controlling and curing the disease. However, it is noted that the patient satisfaction index is not the most encouraging and there is little research that points to the support of the hospital team. The aim of this study was to collect data from medical records about the adverse effect of the disease and through questionnaire the level of knowledge about the disease and the support offered by sector and to make recommendations for radiotherapy units Data were collected from 147 patients and of that total, 51 answered the questionnaire. The survey also shows that there was little referral to the complementary therapeutic service during of treatment. It is identified that more than 50% them knew very little about prostate cancer and 42% had no participation in the choice of treatment. It is observed that it is difficult to insert support policies for patients with prostate cancer, the professionals who work in oncology and radiotherapy centers underestimate the effects of the disease. It is observed, through research, that many of the symptoms and debilitations could be mitigated if there was a greater interaction between the health team and the patient, reducing the effects of radiation and accelerating the patient's integration for the social environment.

Palavras-Chave: neoplasms; patients; prostate; quality of life; radiation effects; radiotherapy; recommendations

FERREIRA, D.C.; DEL MASTRO, N.L. An analysis of the support and quality of live after the diagnosis and treatment of prostate cancer in the radiotherapy sector. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i1A.1384. Disponível em: http://repositorio.ipen.br/handle/123456789/32106. Acesso em: $DATA.

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Abstract: Among many apple products, apple porridge is a popular product nowadays. It is a practical, healthy and tasty product that can be consumed throughout the day. However, it is an extremely perishable product. Therefore, the aim of this work was to evaluate the shelf-life period of apple porridge after the application of gamma radiation as a conservation technology. After the formulation of apple porridge was developed, which was subjected to gamma radiation at the dose of 1kGy in a dose tax of 0.356 kGy.hour-1 and compared this treatment with the control group (0kGy). From the results presented, it can be concluded that the conservation period of apple porridge submitted to gamma radiation is 60 days. From the 90th day, the samples showed microbial growth, becoming not accepted for consumption. In comparison to the control group, the use of gamma radiation was promising, since the standard sample showed contamination before 30 days. By the results it can be concluded that the dose used was adequate for the conservation of this product for the period evaluated.

Palavras-Chave: apples; cobalt 60; coliforms; food processing; fungi; gamma radiation; irradiation; ph value; radiation doses; storage life

HARDER, M.N.C.; BREVIGLIERI, E.; OLIVEIRA, B.B.; ZAMBONI, K.; CARVALHO, S.; NEME-OYAN, F.F.; HARDER, L.N.C.; OLIVEIRA, S.R.; ARTHUR, V. Apple porridge submitted to gamma radiation for shelf-life extended. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1372. Disponível em: http://repositorio.ipen.br/handle/123456789/32104. Acesso em: $DATA.

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Abstract: Iodine is one of the essential trace elements of much interest in nutritional research being responsible for the production of the thyroid hormones, which has great importance for human metabolism. Edible algae species accumulate iodine from seawater and are considered a good dietary source of this nutrient. The Epithermal Neutron Activation Analysis (ENAA) was applied to determine the iodine concentration in edible algae species and derivatives. Twenty-one samples for 4 edible algae species Porphyra umbilicalis (common name: Nori), Hijikia fusiforme (Hijiki), Undaria pinnatifida (Wakame) and Laminaria spp. (Kombu) and 3 samples of the derivative sample, ágar, were analyzed. The results pointed out a great variability of I concentration in these species. The highest I concentration obtained was 9324±113 mg/kg in Laminaria spp. (Kombu). Hijikia fulsiforme (Hijiki) also presented high values (1803±86 mg/kg). The lowest I content was obtained in agar samples (3.18±0.29 mg/kg). All analyzed algae samples exceed the recommended value (150 μg/day) and an ingestion of 1 g/day of Laminaria spp. (Kombu) exceed the maximum tolerable limit (1100 μg/day) and its consumption must be controlled to avoid possible health problems.

Palavras-Chave: algae; concentration ratio; iodine; metabolism; neutron activation analysis; public health; thyroid hormones; trace amounts

ALBUQUERQUE, C.R.; MAIHARA, V.A.; SILVA, P.S.C. Iodine determination in edible algae species using epithermal neutron activation analysis methodology. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-11, 2021. DOI: 10.15392/bjrs.v9i1A.1365. Disponível em: http://repositorio.ipen.br/handle/123456789/32102. Acesso em: $DATA.

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Abstract: Ionizing radiation supplied by cobalt-60 is an excellent alternative tool to the traditional process of decontamination of cultural and historical materials, mainly because of its biocidal action. Analyzing the occurrence of requests for treatment materials from cultural institutions with ionizing radiation for fungal decontamination in the Multipurpose Gamma Irradiation Facility of the Nuclear and Energy Research Institute - CTR/IPEN, there was a need to establish a protocol for the care of institutions and individuals carrying cultural and historical collections. The study proposal was the establishment an efficient and reproducible model of an irradiation protocol for the treatment of cultural heritage materials in industrial irradiators, respecting the ethical principles of conservation and restoration activities. The objective of the protocol is to be a practical guide, from the detection of the problem to the final cleaning, so that conservator-restorers and professionals of the irradiation can act in a collaborative and objective way to reach the objective of the treatment.

Palavras-Chave: cobalt 60; cultural objects; decontamination; disinfestation; fungi; gamma radiation; historical aspects; irradiation; preservation; recommendations

NAGAI, M.L.E.; SANTOS, P.S.; VASQUEZ, P.A.S. Irradiation protocol for cultural heritage conservation treatment. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-16, 2021. DOI: 10.15392/bjrs.v9i1A.1351. Disponível em: http://repositorio.ipen.br/handle/123456789/32100. Acesso em: $DATA.

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Abstract: The scattered radiation from interventional procedures is an important source of radiological risk for the medical staff. Considering all affected organs, the eye lens is among the most critical organs. As pointed out by several studies, even for low radiation doses, the appearance of cataract may occur. Considering this scenario, the radiation doses to the eye lens were determined using three different lead eyewear models commonly employed in the interventional radiology. The interventional radiologist was represented by an adult virtual anthropomorphic phantom (MASH3), coupled to the Monte Carlo code MCNP 6.1, in a typical cardiac interventional radiology procedure. The eyewear had a thickness 0.5 mmPb each, and the evaluation was carried out for four different beam angulations (PA, LAO90, LAO65 e RAO65), utilizing a tube voltage of 80 kVp, and HVL of 4 mmAl. The results pointed out that the shielding efficiency has a strong dependence on the eyewear type utilized, which may be very useful for the decision-making during the acquisition of such equipments.

Palavras-Chave: crystalline lens; equivalent radiation doses; fluoroscopy; glass; lead; monte carlo method; occupational exposure; phantoms; radiation protection; shielding

SANTOS, W.S.; NEVES, L.P.; PERINI, A.P.; SANTOS, C.J.; BELINATO, W.; CALDAS, L.V.E. The influence of the lead eyewear geometry on the doses to the eye lens. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-9, 2021. DOI: 10.15392/bjrs.v9i1A.1347. Disponível em: http://repositorio.ipen.br/handle/123456789/32098. Acesso em: $DATA.

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Abstract: Austenitic stainless steel alloys, mainly those produced according to ISO 5832-1, have received much attention due to their promising characteristics to be used as biomaterials. The aim of this study was to establish the proper conditions of neutron activation analysis (NAA) in order to determine chemical elements in a sample of ISO 5832-1 stainless steel. These determinations are of great interest for further evaluation of its corrosion resistance and of cytotoxicity of corrosion products. For the analyses, chips of ISO 5832-1 austenitic stainless steel were obtained. Aliquots of this material were weighed in polyethylene involucres and irradiated together with synthetic element standards at the IEA-R1 nuclear research reactor. Short and long irradiations were carried out using thermal neutron flux of about 4.5 x 1012 n cm-2 s-1. Quality control of the results was performed by analyzing two certified reference materials (CRMs). The elements concentrations of Cr, Cu, Mn, Mo and Ni obtained in the ISO 5832-1 austenitic alloy are within the specification values of this material. Besides, the elements As, Co, V and W were determined in this alloy. The sensitivity of the technique was verified by the determination of detection and quantification limits. In the case of CRMs, their results presented precision and accuracy for most of elements with relative standard deviations and relative errors lower than 15 %. Results obtained in this study demonstrated the viability of applying NAA in the analysis of the ISO 5832-1 stainless steel alloy.

Palavras-Chave: austenitic steels; biological materials; elements; iear-1 reactor; irradiation; neutron activation analysis; quality control; stainless steels; thermal neutrons

BRAGUIN, L.N.M.; SILVA, C.A.J.; COSTA, I.; SAIKI, M. Neutron activation analysis of austenitic stainless steel used as biomaterial. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-16, 2021. DOI: 10.15392/bjrs.v9i1A.1337. Disponível em: http://repositorio.ipen.br/handle/123456789/32096. Acesso em: $DATA.

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Abstract: Chia seeds (Salvia hispanica L.) is a good source of oil, protein, dietary fiber, minerals and polyphenolic compounds. In order to study the influence of the processing methods on the content of phenolic compounds, the objective of this work was to evaluate the effect of gamma radiation, doses 0 (control), 5, 10 and 20 kGy, on the total phenolic compounds extracted from chia seeds. Seeds were first defatted and extracts produced with proper solvents. Total phenolic content was determined according to Folin-Ciocalteu’s method and the extraction solvents applied were ethanol 100%, ethanol 70%, ethanol 50%, methanol 100%, methanol 70% and methanol 50%. When using ethanol 100%, ethanol 70 %, ethanol 50%, methanol 100% and methanol 70%, the extraction yield was independent of the absorbed dose. With methanol 50%, the irradiation process affected positively the total phenolic yield from of chia seeds. In general, the absorbed dose as well as the nature of the solvent affected the extraction yield, although in a limited manner.

Palavras-Chave: antioxidants; cobalt 60; dose rates; food processing; gamma radiation; irradiation; radiation dose units; radiation effects; seeds

CHIERENTIN, G.S.; TEIXEIRA, B.S.; MASTRO, N.L. Total phenolic compounds of irradiated chia seeds. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-9, 2021. DOI: 10.15392/bjrs.v9i1A.1331. Disponível em: http://repositorio.ipen.br/handle/123456789/32094. Acesso em: $DATA.

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Abstract: The application of multivariate techniques to experimental results requires a responsibility on behalf of the researcher to understand, evaluate and interpret their results, especially the ones that are more complex. The objective of this article is to evaluate the impact of three standardization techniques on the formation of clusters by means of the Kohonen neural network were studied. The standardization techniques studied were logarithm (log), generalized-log and improved minimum-maximum. The studies were performed using two different databases consisting of 298, named B1, and 146 samples, named B2. The B1 dataset is formed by samples that form two cluster very close. However, the B2 dataset form three diferent and separated cluster. The mass fractions of As, Ce, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sc, Sm, Tb, Th, U, and Yb of each sample were determined by instrumental neutron activation analysis, INAA. Three validation indices : Jaccard, Fowlkes-Mallows and Rand were performed on the dataset. The results suggest that when the cluster are close, the improved minimum-maximum satandardization is better than the logarithm and generalized-log. However, when the cluster are separated, the logarithm and generalized-log are better than the improved minimum-maximum technique.

Palavras-Chave: algorithms; cluster analysis; computer codes; datasets; neural networks; neutron activation analysis; standardization; statistical models

NOGUEIRA, A.L.; MUNITA, C.S. The effect of data standardization in cluster analysis. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i1A.1324. Disponível em: http://repositorio.ipen.br/handle/123456789/32092. Acesso em: $DATA.

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Abstract: Measurement uncertainty was estimated following the EURACHEM guide (Quantifying Uncertainty in Analytical Measurement) for the elements As, Br, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Rb, Sb, Se and Zn determined by In-strumental Neutron Activation Analysis (INAA) and for the elements Cd, Hg and Pb determined by Atomic Absorption Spectrometry (AAS) in the fillet of the most consumed fish species at São Paulo city, Brazil. INAA expanded uncertainties ranged from 1.0 to 21% and the main contributions were due the counting statistics of sample and pipetted standards. For AAS, expanded uncertainties ranged from 6.5 to 13% and the main contri-butions were associated to the calibration curves. Uncertainty results were compared with the standard devia-tions of the mass fraction in the fishes (n = 10). Due to the wide variability in the mass fraction in the analyzed fish tissues, explained by factors such gender, age, fat content and fishing location of the specimens of each spe-cies, standard deviations were greater than expanded uncertainties, which means that the natural variability of the elements determined is greater than the data dispersion associated with the analytical techniques. Hence the used techniques were adequate for the fish fillet samples analyses.

Palavras-Chave: absorption spectroscopy; data covariances; evaluation; fishes; neutron activation analysis; toxicity

TAPPIZ, BRUNO; MOREIRA, EDSON G. Expanded uncertainty assessment in fish samples analyzed by INAA and AAS. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1A.1314. Disponível em: http://repositorio.ipen.br/handle/123456789/32090. Acesso em: $DATA.

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Abstract: There is an unwelcome reaction between the coloring and the water during the dyeing procedure, a portion of the coloring agent is lost in the bathing and it will compose the final whole effluent. The high absorbance index is related to lost dyestuffs and they also contribute with the toxic effects to the aquatic biota. In addition, these effluents contain large quantity of surfactants applied during dyeing baths, which also contribute to the high toxicity in these samples. The objective of this study was to evaluate electron beam irradiation technology, applied in samples of the Color Index Reactive Blue 21 (RB 21) dyestuff and in samples of surfactant non-ionic and in order to reduce toxicity for both and for RB 21, color reduction. Among the objectives of the study there are the dyestuff exhaustion degree, and some physical-chemical parameters. The acute toxicity assays were carried with Daphnia similis microcrustacean and the results of the dyestuff solution were: the irradiated samples with concentration 0.61 g L-1 did not present significant results, the EC 50 (%) value was to 58.26 for irradiated sample with 2.5 kGy and EC 50 (%) 63.59 for sample irradiated with 5 kGy. The surfactant was more toxic than RB 21, with EC 50 (%) value at 0.42. The color reduction reached 63.30% for the sample of the lowest concentration of effluent. There was a reduction of pH during irradiation.

Palavras-Chave: color; dyes; electron beams; irradiation; liquid wastes; ph value; reduction; surfactants; toxicity; water

MELO, C.G.; ROSA, J.M.; GARCIA, V.S.G.; BORRELY, S.I.; PEREIRA, M.C.C. Toxicity and color reduction of reactive dyestuff RB 21 and surfactant submitted to electron beam irradiation. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1A.1311. Disponível em: http://repositorio.ipen.br/handle/123456789/32088. Acesso em: $DATA.

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Abstract: New laboratories for brachytherapy sources production are being implemented in our facility at IPEN, in São Paulo. A great challenge implementing a production laboratory is to comply with the Good Manufacturing Practices (GMPs), which involves process validation and all supporting activities such as cleaning and sanitization. Much more than compliance with regulatory guidelines, required for certification and inspections, a validation builds large process knowledge, provides possibilities for optimization and improvement, increasing the degree of maturity of all people involved and the quality system. The process validation results in a document that certifies that any procedure, process, equipment, material, operation, or system leads to the expected results. This work focused on the new laboratory, been assembled to produce small iodine-125 seeds. The process validation was performed three times for evaluation. The parameters evaluated in this study were: the source welding efficiency and the leakage tests results (immersion test). The welding efficiency does not have an established parameter, since is visually evaluated by the operator, and the leakage detection must be under 5 nCi / 185 Bq, accordingly with the ISO 9978. We observed values were average 79-87% production efficiency and leakage tests were under 5 nCi/seed. Although established values for the global efficiency aren’t available in the literature, the results showed high consistency and acceptable percentages, especially when other similar manufacturing processes are used in comparison (average 85-70% found in the literature for other similar metallic structures). Those values will be important data when drafting the validation document and to follow the Good Manufacturing Practices (GMPs).

Palavras-Chave: brachytherapy; certification; implementation; iodine 125; manufacturing; quality control; radiation sources; validation

BAPTISTA, TATYANA S.; FEHER, ANSELMO; RODRIGUES, BRUNA T.; ZEITUNI, CARLOS A.; MOURA, JOÃO A.; ROSTELATO, MARIA E.C.M. A proposal of process validation in the implementation of Good Manufacturing Practices in brachytherapy sources production. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-8, 2021. DOI: 10.15392/bjrs.v9i1A.1285. Disponível em: http://repositorio.ipen.br/handle/123456789/32086. Acesso em: $DATA.

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Abstract: Hydrogels are three-dimensionally crosslinked polymers that exhibit high capacity to absorb water or solvents, without compromising its structure, allowing its application in cosmetic products, because it presents easy scattering and vehicular active principles. The use of ionizing radiation to obtain the hydrogels provides the absence of chemical initiators; sterilization; reticulation and adjustment of physical-chemical properties. In this work different types of hydrogels containing 5 wt%, 7.5 wt% and 10 wt% PVP concentrations and different radiation 25 and 20 kGy doses were prepared, maintaining 3 wt% PEG concentrations and 1 wt% agar, based on literature studies. The samples were characterized by dehydration as a function of time, acidity, visual and sensorial analyzes and stability. The results obtained showed that all the compositions are stable, have a pH close to the skin and the compositions containing 5 wt% PVP, obtained with 20 and 25 kGy radiation dose, undergo greater dehydration. In sensory research, the hydrogels containing 7.5 wt% PVP, obtained with 25 kGy radiation dose, presented the best results in terms of absorption, sliding, odor, while the composition containing 10 wt% PVP, obtained with 25 kGy radiation dose, proved to be inadequate in the public perception. Therefore, the hydrogels obtained with 7.5 wt% PVP, with 25 kGy radiation dose, were the most suitable for applications in cosmetic products.

Palavras-Chave: consumer products; dehydridation; hydrogels; ionizing radiations; irradiation; pvp; radiation doses

BARBOSA, I.T.F.; SEO, E.S.M.; SILVA, L.G.A.; MIRANDA, L.F. Hydrogels applied in cosmetology irradiated by ionizing radiation. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i1A.1278. Disponível em: http://repositorio.ipen.br/handle/123456789/32084. Acesso em: $DATA.

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Abstract: Neural networks, particularly deep neural networks, are used nowadays with great success in several tasks, such as image classification, image segmentation, translation, text to speech, speech to text, achieving super-human performance. In this study, the capabilities of deep learning are explored on a new field: gamma-spectroscopy analysis, comparing the classification performance of different deep neural network architectures. The following architectures where tested: VGG-16, VGG-19, Xception, ResNet, InceptionV3, and MobileNet, which are available through the Keras Deep Learning framework to identify several different radionuclides (Am-241, Ba133, Cd-109, Co-60, Cs-137, Eu-152, Mn-54, Na-24, and Pb-210). Using an HPGe detector to acquire several gamma spectra from different sealed sources to create a dataset used for the training and validation of the neural network's comparison. This study demonstrates the strengths and weaknesses of applying deep learning on gamma-spectroscopy analysis for nuclear waste characterization.

Palavras-Chave: artificial intelligence; computer architecture; gamma spectroscopy; high-purity ge detectors; neural networks; radioactive waste management; radioactive wastes; radioisotopes; sealed sources

OTERO, A.G.L.; POTIENS JUNIOR, A.J.; MARUMO, J.T. Comparing deep learning architectures on gamma-spectroscopy analysis for nuclear waste characterization. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-8, 2021. DOI: 10.15392/bjrs.v9i1A.1257. Disponível em: http://repositorio.ipen.br/handle/123456789/32082. Acesso em: $DATA.

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Abstract: The production of molybdenum-99 (99Mo) using low-enriched uranium targets (< 20% 235U) dispersed in aluminum (UAlx) is a very promising strategy towards the independence in 99Mo local production. A thorough control must be performed to ensure that these targets meet the regulatory requirements to achieve the expected efficiency in the reactor. The determination of the targets’ composition is of high interest, because the distribution of Al in different phases may have an impact on the U concentration. Among the techniques used for this purpose, inductively coupled plasma optical emission spectrometry (ICP OES) stands out because of its high sensitivity and precision, allowing for simultaneous determination of several elements in a variety of samples and matrices. However, because U exhibits a complex emission spectrum, spectral interferences are prone to affect the analysis of Al, calling for time consuming preparation steps to remove the U from the matrix. This study proposes a method of direct determination of Al in UAlx targets through the selection of specific emission lines enabled by the evaluation of the associated interferences on the recovery values.

Palavras-Chave: aluminium; chemical analysis; emission spectroscopy; molybdenum 99; plasma; technetium 99; uranium 235 target

GUILHEN, S.N.; SOUZA, A.L.; COTRIM, M.E.B.; PIRES, M.A.F. Direct determination of aluminum in low-enriched UAlx targets (UAlx-Al) by ICP OES. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i1A.1247. Disponível em: http://repositorio.ipen.br/handle/123456789/32080. Acesso em: $DATA.

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Abstract: Humans are exposed to natural radiation; soil is a major source of external and internal exposure of radiation. The aim of this study is to evaluate the exposure levels of terrestrial biota and to estimate the radiation exposure around Instituto of Pesquisas Energéticas e Nucleares (IPEN) facilities. The ERICA Tool was used to calculate the exposure levels of terrestrial biota; the estimation of radiation exposure for humans was determined using a model proposed by UNSCEAR and Excess Lifetime Cancer Risk. Six soil points were collected and their activity concentrations were measured by gamma spectrometry. Two soil points showed a risk coefficient greater than 1, suggesting that the screening dose ratio of 10μGy h-1 might be exceeding for the most exposed species, namely lichen and bryophytes, even though the activity concentration values of the analyzed radionuclides showed no evidence of soil contamination due to the atmospheric discharges of the IPEN facilities. Thus, the radioactive discharges in the soil from all facilities are negligible. Hence, the authors concluded that the ERICA Tool can be useful in assisting environmental radiological monitoring program for decision-making, especially regarding: points collected, sample types and sampling frequency.

Palavras-Chave: activity levels; bryophyta; environmental exposure pathway; gamma spectroscopy; high-purity ge detectors; human populations; ionizing radiations; lichens; soils; unscear

CAVALCANTE, F.; NISTI, M.B.; SAUEIA, C.H.R. Estimation of exposure levels of terrestrial biota and radiation exposure around IPEN’s facilities. Brazilian Journal of Radiation Sciences, v. 9, n. 1A, p. 1-13, 2021. DOI: 10.15392/bjrs.v9i1A.1235. Disponível em: http://repositorio.ipen.br/handle/123456789/32078. Acesso em: $DATA.

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Abstract: The aim of this work is to present a comparative analysis in terms of the irradiation performance of cylindrical uranium dioxide fuel rods and monolithic uranium molybdenum fuel plates in pressurized light water reactors. To analyze the irradiation performance of monolithic uranium molybdenum fuel plates when subjected to steady state operating conditions in light water pressurized reactors, the computer program PADPLAC-UMo was used, which performs thermal and mechanical analysis of the fuel taking into account the physical , chemicals and irradiation effects to which this fuel is subjected. For the analysis of the uranium dioxide fuel rods, the code FRAPCON was used, which is an analytical tool that verifies the irradiation performance of fuel rods of pressurized light water reactor, when the power variations and the boundary conditions are slow enough for the term permanent regime to be applied. The analysis for a small nuclear power reactor, despite the higher power density applied to the fuel plate in relation to the fuel rod, showed that the fuel plates have lower temperatures and lower fission gas releases throughout the analyzed power history, allowing the use of a more compact reactor core without exceeding the design limits imposed on nuclear fuel.

Palavras-Chave: computer codes; computerized simulation; molybdenum; nuclear fuels; performance; power reactors; uranium

SILVA, A.L.C.; SILVA, A.T. Comparison of computer programs to analyze the irradiation performance of U-Mo monolithic fuel plates and UO2 cylindrical fuel rods in power reactors. Brazilian Journal of Radiation Sciences, v. 9, n. 1, p. 1-17, 2021. DOI: 10.15392/bjrs.v9i1.1604. Disponível em: http://repositorio.ipen.br/handle/123456789/32076. Acesso em: $DATA.

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Abstract: Samarium is currently used in many applications, such as catalysts, lasers and metal alloys. Samarium is also employed to absorb neutrons in nuclear reactors. In medicine, samarium is used in the form of radioactive 153Sm to produce radiopharmaceuticals. A simple process for the preparation of pure samarium acetate was studied. The raw material, which was used in the form of rare earth carbonates was produced industrially from the chemical treatment of Brazilian monazite. Ion exchange chromatography was performed using a strong cationic resin to fractionate rare earth elements (REE). Under these conditions, 99.9% pure Sm2O3 and yield greater than or equal 60% was eluted by ammonium salt of ethylenediaminetetraacetic acid (EDTA) solution in con-trolled pH. The EDTA-samarium complex was transformed into samarium oxide, which was subsequently dis-solved in acetic acid to obtain the samarium acetate. Molecular absorption spectrophotometry was used to moni-tor the samarium and sector field inductively coupled plasma mass spectrometry was used to certify the purity of the samarium acetate. The solid salt was characterized by chemical analysis, thermal analysis, infrared spectros-copy and X ray diffraction. The analytical data collected allowed to conclude that stoichiometric formula for the samarium acetate obtained is Sm(CH3COO)3.4.H2O.

Palavras-Chave: edta; fourier transformation; icp mass spectroscopy; impurities; infrared spectra; ion exchange chromatography; production; samarium oxides; thermal gravimetric analysis

QUEIROZ, CARLOS A. da S.; PEDREIRA FILHO, WALTER dos R. Production of high purity samarium acetate for use in nuclear area. Brazilian Journal of Radiation Sciences, v. 9, n. 1, p. 1-14, 2021. DOI: 10.15392/bjrs.v9i1.1265. Disponível em: http://repositorio.ipen.br/handle/123456789/32074. Acesso em: $DATA.

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Abstract: Among the medical uses of ionizing radiations, the computed tomography (CT) diagnostic exams are responsible for the highest dose values to the patients. The dosimetry procedure in CT scanner beams makes use of pencil ionization chambers with sensitive volume lengths of 10 cm. The aim of its calibration is to compare the values that are obtained with the instrument to be calibrated and a standard reference system. However, there is no primary standard system for this kind of radiation beam. Therefore, an extrapolation ionization chamber, built at the Calibration Laboratory (LCI), was used to establish a CT primary standard. The objective of this work was to perform some characterization tests (short- and medium-term stabilities, saturation curve, polarity effect and ion collection efficiency) in the standard X-ray beams established for computed tomography at the LCI.

Palavras-Chave: calibration; computerized tomography; extrapolation chambers; performance; radiation doses; saturation; stability; x radiation

CASTRO, MAYSA C.; SILVA, NATALIA F.; CALDAS, LINDA V.E. Performance of an extrapolation chamber in computed tomography standard beams. Brazilian Journal of Radiation Sciences, v. 8, n. 3B, p. 1-8, 2021. DOI: 10.15392/bjrs.v8i3B.376. Disponível em: http://repositorio.ipen.br/handle/123456789/32072. Acesso em: $DATA.

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Abstract: To characterize the physicomechanical properties of an alumina-toughened zirconia (ATZ). ATZ synthesis consisted of the addition of alumina particles in an yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) matrix. Specimens were obtained by uniaxial and isostatic pressing ATZ and 3Y-TZP powders and sintering at 1600°C/1 h and 1550°C/1 h, respectively. Crystalline content and residual stress were evaluated using X-ray diffraction (XRD). Microstructure was characterized by scanning electron microscopy (SEM). Optical properties were determined by reflectance test. Mechanical properties were assessed by biaxial flexural strength test. All analyses were performed before and after aging (134°C, 20 h, 2 bar). XRD and SEM revealed a typical ATZ and 3Y-TZP crystalline content, chiefly tetragonal phase, with a dense polycrystalline matrix, though a smaller grain size for ATZ. Aging triggered a similar monoclinic transformation for both systems; however, ATZ exhibited higher residual compressive stresses than 3Y-TZP. While as-processed 3Y-TZP demonstrated significantly higher characteristic strength relative to ATZ, no significant difference was observed after aging (~215 MPa increase in the ATZ strength). ATZ presented significantly higher opacity relative to 3Y-TZP, although aging significantly increased the translucency of both systems (increase difference significantly higher in the 3Y-TZP compared to ATZ). ATZ physicomechanical properties support its applicability in the dental field, with a lower detrimental effect of aging relative to 3Y-TZP.

Palavras-Chave: zirconium; dentistry; ceramics; composite materials; optical properties; aging

BERGAMO, EDMARA T.P.; CARDOSO, KARINA B.; LINO, LUCAS F.O.; CAMPOS, TIAGO M.B.; MONTEIRO, KELLI N.; CESAR, PAULO F.; GENOVA, LUIS A.; THIM, GILMAR P.; COELHO, PAULO G.; BONFANTE, ESTEVAM A. Alumina-toughened zirconia for dental applications: physicochemical, mechanical, optical, and residual stress characterization after artificial aging. Journal of Biomedical Materials Research Part B: Applied Biomaterials, v. 109, n. 8, p. 1135-1144, 2021. DOI: 10.1002/jbm.b.34776. Disponível em: http://repositorio.ipen.br/handle/123456789/32070. Acesso em: $DATA.

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Abstract: We quantify plastic litter (PL, > 2 cm) and microplastics (MP, < 5 mm) from the sediments of a beach formed at a riverine depositional area, at the upper Amazon River basin, Ecuador. In the collection area (4400 m2), the PL density was 0.045 items m−2, where low-density polyethylene bags were the prevalent PL. The beach was classified as “very clean” (Clean Coast Index (CCI) of 1.3 items m−2). Regarding MP, in 55 sampling stations, average MP concentrations ranged from 0 to 2200 items kg−1 of dry sediment (0.5–2 mm), and 0–4200 items kg−1 of dry sediment (2–5 mm). Blue fibers were the prevalent MP. Our results represent the first report to show the ubiquitous presence of PL and MP for the area. The monitoring and management of plastic disposal in freshwater beaches are necessary, as here we report a small part of an undocumented issue.

Palavras-Chave: plastics; waste water; water pollution; sewage; rivers; waste processing

LUCAS-SOLIS, OSCAR; MOULATLET, GABRIEL M.; GUAMANGALLO, JENIFFER; YACELGA, NAOMI; VILLEGAS, LIPSI; GALARZA, EMILY; ROSERO, BRYAN; ZURITA, BRYAN; SABANDO, LIZETH; CABRERA, MARCELA; GIMILIANI, GIOVANA T.; CAPPARELLI, MARIANA V. Preliminary assessment of plastic litter and microplastic contamination in freshwater depositional areas: the case study of Puerto Misahualli, Ecuadorian Amazonia. Bulletin of Environmental Contamination and Toxicology, v. 107, n. 1, p. 45-51, 2021. DOI: 10.1007/s00128-021-03138-2. Disponível em: http://repositorio.ipen.br/handle/123456789/32068. Acesso em: $DATA.

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Abstract: Wavelengths in the yellow-orange range are of significant interest for retinal photocoagulation and are especially important in the case of diabetic retinopathy, which can cause blindness and affects 3.3% of all working-age adults. This work presents a highly-efficient, compact, and cost-efficient side-pumped, intracavity Raman configuration to achieve this objective. A side-pumped Nd:YLF/KGW/LBO frequency-doubled Raman laser producing 11.7 W of output power at 1147 nm with 21% of slope efficiency and 6 W of output power at 573.5 nm with 12% slope efficiency is demonstrated.

Palavras-Chave: retina; lasers; crystals; diode-pumped solid state lasers; ophthalmology; diabetes mellitus

FERREIRA, MERILYN S.; WETTER, NIKLAUS U. Diode-side-pumped, intracavity Nd:YLF/KGW/LBO Raman laser at 573 nm for retinal photocoagulation. Optics Letters, v. 46, n. 3, p. 508-511, 2021. DOI: 10.1364/OL.411895. Disponível em: http://repositorio.ipen.br/handle/123456789/32066. Acesso em: $DATA.

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Abstract: This work presents the feasibility studies to convert the UO2 core of the Westinghouse AP1000 reactor to a U/Th core aiming at U/Th fuel recycling. The focus of the work is to establish a first core which allows normal operation of the AP1000 reactor and investigate a possible route for generating the 233U for U/Th fuel recycling. The converted core named AP-Th1000 is divided in three homogenous zones with different UO2/ThO2 mass proportions. The reprocessing procedure envisioned is to separate fission products and Pu isotopes, retain Uranium, use this fuel material in subsequent fuel cycles and complement the required fissile material with U with enrichment below 20%. The goal was to gradually reduce the mass proportion of mined Uranium fuel and eventually attain a Th-233U core with similar operation characteristics of current AP1000 core. We perform a detailed three-dimensional full core analysis with the SERPENT code examining core reactivity, power density distribution, and also a preliminary closed cycle study for the first 4 cycles where the production of 233U are evaluated. The goal of converting the AP1000 reactor core to a U/ThO2 fuel cycle was partially accomplished. While the first cycle was thoroughly examined and met all requirements we were not able to find a route to migrate it to a prevalent Th cycle. Basically, two of the set of criteria adopted in the study proved to be too restrictive to attain this goal with homogenous assembly, namely U enrichment below 20% and not recycling Pu. The results indicate that removing these two criteria the conversion factor in the ensuing fuel cycles can be increased and possibly attain a Th cycle without compromising the economics of power generation. The design changes were the elimination of IFBA burnable absorbers and replacement of gray control bundles by black control bundles.

Palavras-Chave: thorium; pwr type reactors; reactor cores; fuel cycle

STEFANI, GIOVANNI L. de; MAIORINO, JOSE R.; MOREIRA, JOAO M. de L. The AP-Th 1000: an advanced concept to use MOX of thorium in a closed fuel cycle. International Journal of Energy Research, v. 45, n. 8, p. 11642-11655, 2021. SI, DOI: 10.1002/er.5421. Disponível em: http://repositorio.ipen.br/handle/123456789/32064. Acesso em: $DATA.

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Abstract: Background Peri-implantitis treatments are mainly based on protocols for teeth but have not shown favorable outcomes for implants. The potential role of titanium dissolution products in peri-implantitis necessitate the consideration of material properties in devising treatment protocols. We assessed implant cleaning interventions on (1) bacterial removal from Ti-bound biofilms, (2) Ti surface alterations and related Ti particle dissolution, and (3) cytocompatibility. Methods Acid-etched Ti discs were inoculated with human peri-implant plaque biofilms and mechanical antimicrobial interventions were applied on the Ti-bound biofilms for 30 seconds each: (1) rotary nylon brush; (2) Ti brush; (3) water-jet on high and (4) low, and compared to sterile, untreated and Chlorhexidine-treated controls. We assessed colony forming units (CFU) counts, biofilm removal, surface changes via scanning electron microscopy (SEM) and atomic force microscopy (AFM), and Ti dissolution via light microscopy and Inductively-coupled Mass Spectrometry (ICP-MS). Biological effects of Ti particles and surfaces changes were assessed using NIH/3T3 fibroblasts and MG-63 osteoblastic cell lines, respectively. Results Sequencing revealed that the human biofilm model supported a diverse biofilm including known peri-implant pathogens. WJ and Nylon brush were most effective in reducing CFU counts (P < 0.01 versus control), whereas Chlorhexidine was least effective; biofilm imaging results were confirmatory. Ti brushes led to visible streaks on the treated surfaces, reduced corrosion resistance and increased Ti dissolution over 30 days of material aging as compared to controls, which increase was amplified in the presence of bacteria (all P-val < 0.05). Ti particles exerted cytotoxic effects against fibroblasts, whereas surfaces altered by Ti brushes exhibited reduced osteoconductivity versus controls (P < 0.05). Conclusions Present findings support that mechanical treatment strategies selected for implant biofilm removal may lead to Ti dissolution. Ti dissolution should become an important consideration in the clinical selection of peri-implantitis treatments and a necessary criterion for the regulatory approval of instruments for implant hygiene.

Palavras-Chave: dentistry; implants; titanium; bacteria; corrosion; surface properties; antimicrobial agents