Abstract: This review is focused on the long-term performance of cementitious materials in a repository for radioactive waste. During the last few years, the disposal of disused sealed radioactive sources (DSRS) in a borehole type repository has been studied by many countries. The borehole concept is particularly useful to dispose of spent nuclear fuel and DSRS. In boreholes for DSRS, cementitious materials are intended to be used as structural material, immobilization matrix and as backfill. The understanding of the performance of these materials is essential to ensure the safety of the facilities during their required lifetime, from centuries to many thousands of years, depending on the initial activity and half-life of the waste. This review approaches the behavior of the cement from the hydration and hardening to the long-term processes that can affect its durability. Three main causes of failure of repository-engineered barriers are recognized: a) the formation of a preferential pathway for the migration of the contained radionuclides to the biosphere; b) loss of resistance and cohesion of the structural cementitious material; and c) the increase in the corrosion processes of the metallic components of the structures that affect the overall containment of the facility.

Palavras-Chave: cement industry; portland cement; radioactive wastes; geologic formations; underground disposal; performance; chemical composition; mineralogy; radiations; magnetic fields; hydration

FERREIRA, EDUARDO G.A.; MARUMO, JULIO T.; FRANCO, MARGARETH K.K.D.; YOKAICHIYA, FABIANO; VICENTE, ROBERTO. 10000 years cement: Can hydrated cement last as much as long-lived radionuclides?. Cement and Concrete Composites, v. 103, p. 339-352, 2019. DOI: 10.1016/j.cemconcomp.2019.05.016. Disponível em: http://repositorio.ipen.br/handle/123456789/30368. Acesso em: $DATA.

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Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.

Palavras-Chave: hydrogels; drugs; synthesis; cross-linking; skin; animal tissues; gamma radiation

LIMA, CAROLINE S.A. de; BALOGH, TATIANA S.; VARCA, JUSTINE P.R.O.; VARCA, GUSTAVO H.C.; LUGAO, ADEMAR B.; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970. Disponível em: http://repositorio.ipen.br/handle/123456789/31809. Acesso em: $DATA.

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Abstract: This work aimed to analyze the fungal contamination of air-conditioning filter waste (n=15) as an indicator of Quality Air Indoor from different car models in São Paulo city in São Paulo State, Brazil, during the period from October 2018 to July 2019. Three different treatments were used for the decontamination of car air conditioning filters, such as mechanical vacuum cleaning (I), vacuum cleaning and use of sanitizing product (II), and sanitizing product associated with radiation treatment at a dose of 17 kGy (III). After the treatments, microbiological analyses were performed and samples were plated in Petri dishes containing Sabouraud agar transferred by Swabs, and incubated for 7 days at 25 °C. The Petri dishes were stored in a standard Biochemical Oxygen Demand incubator, for the growth of fungal cultures. After incubation, the fungal cultures were evaluated, and the fungal counting was expressed in unit-forming colonies (UFC) and frequency in samples (%). The fungi were examined by lactophenol blue solution staining for microscopy. All samples of treatment I and II were contaminated with various fungal genera and high bioburden, namely (treatment I) Alternaria alternata, Aspergillus flavus, A. niger, Cladosporium spp., Fusarium spp., Mucor spp., Nigrospora spp., Not Sporulated Fungi (NSF), Penicillium spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp. and yeasts. Treatment II showed Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. ochraceus, Cladosporium spp., Mucor spp., NSF, Penicillium spp., Phoma spp., Rhizopus spp., Rhodotorula spp., Trichoderma spp., and yeasts. Treatment III presented NSF and yeasts, with 80% of material decontamination.

Palavras-Chave: absorbed radiation doses; air conditioners; air conditioning; cryogenics; environmental quality; fungi; heating; indoor air pollution; irradiation; pollutants; radiation doses; vehicles

AQUINO, S.; LIMA, J.E.A.; BORRELY, S.I. Combined application of gamma radiation, cleaning and chemical sanitizers in decontamination of vehicle air conditioning filters. Brazilian Journal of Radiation Sciences, v. 11, n. 2, p. 1-11, 2023. DOI: 10.15392/2319-0612.2023.2244. Disponível em: http://repositorio.ipen.br/handle/123456789/34217. Acesso em: $DATA.

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Abstract: The increased environmental impact and sustainability issues related to conventional food packaging have gained attention and led to a global concern. The massive consumption of conventional food packaging has increased disposal of non-eco-friendly packaging waste, severely damaging the environment. The replacement by sustainable packaging is an important alternative to reduce the enormous volume of plastic waste. In this work, bionanocomposite films composed of PBAT/PLA blend and cellulose nanocrystals (CNCs) extracted from agro-waste were investigated. Characterization of CNCs confirmed that nanocrystals were obtained. Bionanocomposite films presented better hydrophobic character and thermal stability than the blend film. In addition, the tensile strength, elongation at break, and Young's modulus was around 52%, 29%, and 118%, respectively, higher than blend films. These mechanical values were comparable to values of commercial plastic materials that are extensively used in food packaging. Thus, the prepared bionanocomposite films might be an interesting alternative to produce sustainable food packaging materials.

Palavras-Chave: cellulose; nanocrystals; food; packaging; nanocomposites; sugar cane; bagasse; agricultural wastes

ANDRADE, MARCIO S.; ISHIKAWA, OTAVIO H.; COSTA, ROBSON S.; SEIXAS, MARCUS V.S.; RODRIGUES, RITA C.L.B.; MOURA, ESPERIDIANA A.B. Development of sustainable food packaging material based on biodegradable polymer reinforced with cellulose nanocrystals. Food Packaging and Shelf Life, v. 31, p. 1-10, 2022. DOI: 10.1016/j.fpsl.2021.100807. Disponível em: http://repositorio.ipen.br/handle/123456789/32970. Acesso em: $DATA.

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Abstract: In this work, the biodegradable poly(butylene adipate-co-terephthalate) (PBAT)/ poly(lactic acid) (PLA) blend (ECOVIO®) and lignin, a renewable and biodegradable natural polymer with high UV absorption and modified by gamma radiation were used to produce agriculture mulch films. Lignin was gammairradiated at 30 and 60 kGy. The irradiated and non-irradiated lignin content of 2 wt% was incorporated into PBAT/PLA blend matrix using a twin-screw extruder and extrusion blown film to prepare flexible films. PBAT/PLA/LIGNIN films were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), tensile tests, contact angle, and UV–Vis analysis. FTIR spectra showed partial miscibility between PBAT/PLA and lignin, being intensified in irradiated lignin compounds. The DSC and XRD results confirmed that the degree of crystallinity of the blends was not significantly influenced by lignin addition. FE-SEM images showed better dispersion and miscibility in PBAT/PLA/Irradiated lignin. Miscibility improvement provided by irradiated lignin promoted better mechanical properties, mainly with lignin irradiated at 60 kGy. PBAT/PLA/LIGNIN films containing 2 wt% showed excellent UV-barrier property and greater hydrophobicity. Summing up, incorporation of low contents of irradiated lignin could be an interesting alternative to produce biodegradable UV-blocking agriculture mulch films.

BARROS, JANETTY J.P.; OLIVEIRA, RENE R.; LUNA, CARLOS B.B.; WELLEN, RENATE M.R.; MOURA, ESPERIDIANA A.B. Effectiveness of modified lignin on poly(butylene adipateco-terephthalate)/poly(lactic acid) mulch film performance. Journal of Applied Polymer Science, v. 140, n. 46, p. 1-12, 2023. DOI: 10.1002/app.54684. Disponível em: http://repositorio.ipen.br/handle/123456789/34249. Acesso em: $DATA.

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Abstract: This study presents a systematic analysis of the influence of irradiation conditions (absorbed dose, temperature, and atmosphere) on the physicochemical properties of radiation-induced grafted anion-exchange membranes (AEMs) based on low-density polyethylene (LDPE). Detailed characterization of the polymeric electrolytes shows striking effects of the irradiation conditions on the AEM properties. The LDPE films are irradiated both at room temperature (RT) and low temperature (LT, ∼ −10 °C). At each temperature, samples are irradiated in air as well as nitrogen. By lowering the sample temperature from RT to LT during irradiation in air it is possible to obtain a threefold increase in the degree of grafting (DoG). The higher DoG reflects in the OH− conductivity (σ) of the AEM irradiated at LT, which exhibits σ (T = 80 °C) = 215 mS cm−1, while the sample prepared at RT and air has σ (T = 80 °C) = 127 mS cm−1. Such high conductivity of the LT irradiated LDPE-AEM results in high-performance anion-exchange membrane fuel cell (AEMFC) with enhanced stability, as inferred from the time dependence of σ (T = 60 °C) measurements. The experimental results evidence that the control of both the irradiation temperature and the atmosphere diminishes the degradation effects caused by the radiation. Therefore, the present study advances the understanding of the role played by the irradiation process on the final properties of radiation-induced grafted LDPE-based AEMs and offers new possibilities to guide future developments for anion-exchange membranes.

Palavras-Chave: polyethylenes; density; anions; ion exchange; membranes; fuel cells

BARBOSA, ANDREY S.; BIANCOLLI, ANA L.G.; LANFREDI, ALEXANDRE J.C.; RODRIGUES JUNIOR, ORLANDO; FONSECA, FABIO C.; SANTIAGO, ELISABETE I. Enhancing the durability and performance of radiation-induced grafted low-density polyethylene-based anion-exchange membranes by controlling irradiation conditions. Journal of Membrane Science, v. 659, p. 1-12, 2022. DOI: 10.1016/j.memsci.2022.120804. Disponível em: http://repositorio.ipen.br/handle/123456789/33430. Acesso em: $DATA.

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Abstract: We report on the chemical and the carbon isotopic composition of dissolved inorganic carbon (DIC) of rainwater collected between May and October 2020 in the Central Valley, Costa Rica. Precipitation samples were collected daily (N = 55) and analyzed for major ions, DIC, and δ13CDIC. Significant correlation (p < 0.05) between main acidic (SO4 2− and NO3 − ) and major alkaline (Ca2+ and NH4 +) species confirmed a very effective acid neutralization effect in rainwater (average pH: 5.90 ± 0.74). Significant temporal variations (p < 0.05) of δ13CDIC indicated the contribution of carbonate salts in rainwater from May to October but also CO2 dissolution at the beginning of the wet season (May), probably due to increased CO2 emissions from soil degassing. Temporal changes of Ca2+ neutralization factors followed the observed changes in δ13CDIC, which confirmed the high buffer capacity of precipitation in our study. HYSPLIT analysis also revealed long-range contributions of pedogenetic carbonates (e. g., Saharan dust) responsible for the acid neutralization capacity of rainwater (e.g., from July to September). Principal component analysis showed that four main factors explain 65% of the variance are: i) acid neutralization processes (Ca2+ neutralization factor), ii) marine salts (Cl− , Na+), iii) fossil fuels (SO4 2− , NO3 − ), and iv) agriculture/fertilizers (NO3 − , NH4 +, K+). Our study demonstrated that a combined approach of chemical, isotope, and statistical analysis techniques can help unravel the mechanism of acid neutralization of rainwater in tropical urban areas. This information has strong implications for future studies related with the impact of acid deposition on ecosystem functioning, water quality, and infrastructure degradation.

Palavras-Chave: urban areas; rain water; chemical composition; carbon isotopes; stable isotopes; tropical regions; inorganic compounds

ESQUIVEL-HERNANDEZ, GERMAIN; SANCHEZ-MURILLO, RICARDO; VILLALOBOS-CORDOBA, DIEGO; MONTEIRO, LUCILENA R.; VILLALOBOS-FORBES, MARIO; SANCHEZ-GUTIERREZ, ROLANDO; COTRIM, MARYCEL E.B.; MATIATOS, IOANNIS. Exploring the acid neutralizing effect in rainwater collected at a tropical urban area: Central Valley, Costa Rica. Atmospheric Pollution Research, v. 14, n. 9, p. 1-12, 2023. DOI: 10.1016/j.apr.2023.101845. Disponível em: http://repositorio.ipen.br/handle/123456789/34212. Acesso em: $DATA.

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Abstract: Identifying the origin of NOx emissions, their transformation into nitrate (NO3−) and its atmospheric deposition is important to better understand the impacts of air pollution on the environment and human health, on a local and regional scale. We measured nitrate isotopes (δ15N, δ18O of NO3−) in precipitation samples in a tropical station in Brazil in 2019–2020 and combined them with chemical, geospatial and meteorological data to trace NOx sources towards their wet deposition as NO3−. A total wet N deposition of ∼12 kg N/ha.year showed significant N air pollution, out of which the relative contribution of NO3−-N was ∼37% (4.6 kg NO3−-N/ha.year). The δ15N–NO3- values in precipitation ranged from −8.5 to +4.1‰, with a volume-weighted mean (VWM) value of −3.0 ± 2.7‰, whereas the δ18O–NO3- values ranged from +25.9 to +63.5‰ with a VWM value of +53.3 ± 7.3‰. The δ15N–NO3- results combined with air mass backward trajectory analysis and geospatial mapping revealed that the NOx emissions in Belo Horizonte originated from: vehicles and industries from the urban and industrialized areas, biomass burning related to wildfires, and ship emissions from the coastal areas. The temporal variation of δ15N, δ18O of NO3− values was attributed to NOx source variability and transformation processes. The use of integrated methods to evaluate the imprints of anthropogenic air pollution sources in Brazil will contribute to inform NOx source management strategies and improve air and water quality.

Palavras-Chave: stable isotopes; washout; nitrogen oxides; geographic information systems; air pollution; pollution sources

PASSOS, RICARDO G.; MATIATOS, IOANNIS; MONTEIRO, LUCILENA R.; ALMEIDA, RAFAEL S.S.P.; LOPES, NILVA P.; CARVALHO FILHO, CARLOS A.; COTA, STELA D.S. Imprints of anthropogenic air pollution sources on nitrate isotopes in precipitation in a tropical metropolitan area. Atmospheric Environment, v. 288, p. 1-14, 2022. DOI: 10.1016/j.atmosenv.2022.119300. Disponível em: http://repositorio.ipen.br/handle/123456789/33372. Acesso em: $DATA.

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Abstract: One of the methods of protein crosslinking used in the synthesis of protein-based nanoparticles is the formation of bityrosine bridges, which may be achieved by the recombination of phenoxyl-type radicals in irradiated protein solutions. Radiation-induced formation of phenoxyl radicals in tyrosine is promoted in presence of H+. In this work, kinetics of this process and the influence of pH were studied by pulse radiolysis measurements of a model peptide H-Gly-Tyr-Gly-OH (GYG), which may help to solve questions raised for bigger, more complex systems in comparable conditions. The main route of phenoxyl radicals formation consists of the addition reaction of hydroxyl radical to the phenol ring on the tyrosine side-chain and proton catalyzed water molecule elimination. A similar effect was observed in studies of tripeptide solutions containing phosphate buffer. The presented data include time-resolved optical spectroscopy of transient species formed under pulse electron beam irradiation and a comparison of the kinetics of the phenoxyl radicals formation in samples at various pH and in presence of phosphate buffer. The postulated mechanism and obtained values of rate constants of the formation and decay of transient species were additionally checked by simple probabilistic simulations.

Palavras-Chave: ionizing radiations; radiolysis; tyrosine; proteins

SOWINSKI, SEBASTIAN; VARCA, GUSTAVO H.C.; KADLUBOWSKI, SLAWOMIR; LUGAO, ADEMAR B.; ULANSKI, PIOTR. A mechanistic approach towards the formation of bityrosine in proteins by ionizing radiation: GYG model peptide. Radiation Physics and Chemistry, v. 188, p. 1-8, 2021. DOI: 10.1016/j.radphyschem.2021.109644. Disponível em: http://repositorio.ipen.br/handle/123456789/32383. Acesso em: $DATA.

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Abstract: Fungal bioburdens in filters from car air conditioning systems represent a potential risk of respiratory or pulmonary diseases to both passengers and drivers. The present study demonstrated high fungal contamination in air conditioning filters collected from fifty-seven vehicles from the city of São Paulo, Brazil. The filters samples were irradiated with 10, 15 and 20 kGy gamma ray doses with a cobalt-60 source. The presence of Aspergillus flavus, Penicillium glabrum and Fusarium incarnatum-equiseti remaining after the ionizing treatment with 10 and 15 kGy. The radioresistant pathogenic species was confirmed through genetic sequencing of the ITS, β-tubulin and calmodulin gene rDNA regions. The 20 kGy dose was efficient in inhibiting pathogenic fungi growth in all samples but promoted the fungal decontamination in 79% of the samples. These results and other efforts will enable ionizing radiation to become an important tool in contributing to the recycling of automotive vehicle air filters and in ensuring indoor air quality for both drivers and passengers.

Palavras-Chave: ionizing radiations; air quality; indoor air pollution; vehicles; air conditioning; fungal diseases; air filters; air cleaning systems

AQUINO, SIMONE; LIMA, JOSE E.A. de; REIS, TATIANA A. dos; CORREA, BENEDITO; BORRELY, SUELI I. Mycoflora and DNA sequencing analysis of radioresistant fungi isolated from irradiated vehicular air conditioning filters collected in São Paulo, Brazil. Microbiology Research International, v. 9, n. 1, p. 1-15, 2021. DOI: 10.30918/MRI.91.21.011. Disponível em: http://repositorio.ipen.br/handle/123456789/32045. Acesso em: $DATA.

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