Navegação por Autores IPEN "VASQUEZ, PABLO A.S."

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  • IPEN-DOC 23168

    GALANTE, RAQUEL; REDIGUIERI, CAROLINA F.; KIKUCHI, IRENE S.; VASQUEZ, PABLO A.S. ; COLACO, ROGERIO; SERRO, ANA P.; PINTO, TEREZINHA J.A.. About the sterilization of chitosan hydrogel nanoparticles. Plos One, v. 11, n. 12, 2016. DOI: 10.1371/journal.pone.0168862

    Abstract: In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP) associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility) with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate the effect and effectiveness of different sterilization methods on chitosan (CS) hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation), a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP) hydrogel nanoparticles (CS-HNP), with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol). Properties like size, zeta potential, absorbance, morphology, chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.

    Palavras-Chave: sterilization; oligosaccharides; hydrogels; nanoparticles; drug delivery; biological materials

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  • IPEN-DOC 17185

    CARVALHO, DIEGO V. de S.; KIRITA, RODRIGO; MESQUITA, CARLOS H. de ; VASQUEZ, PABLO A.S. ; HAMADA, MARGARIDA M. . Analysis of a multiphase phanton using industrial computerized tomographic system developed at IPEN. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 10th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 17th; MEETING ON NUCLEAR INDUSTRY, 2nd, October 24-28, 2011, Belo Horizonte, MG. Proceedings... Sao Paulo: ABEN, 2011, 2011.

    Palavras-Chave: brazilian cnen; phantoms; industrial radiography; computerized tomography

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  • IPEN-DOC 17203

    KIRITA, RODRIGO; CARVALHO, DIEGO V. de S.; MESQUITA, CARLOS H. de ; VASQUEZ, PABLO A.S. ; HAMADA, MARGARIDA M. . Analysis of an industrial process simulator column using third-generation computed tomography. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 10th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 17th; MEETING ON NUCLEAR INDUSTRY, 2nd, October 24-28, 2011, Belo Horizonte, MG. Proceedings... Sao Paulo: ABEN, 2011, 2011.

    Palavras-Chave: brazilian cnen; laboratories; computerized tomography; simulators; industrial plants; gamma radiation

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  • IPEN-DOC 28095

    VIEIRA, ANA C.D.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. ; GARCIA, RAFAEL H.L. . Application of gamma irradiation to conservation: effects of ionizing radiation on the color of featherwork. In: ICOM-CC TRIENNIAL CONFERENCE, 19th, May 17-21, 2021, Beijing, China. Abstract... Paris, France: International Council of Museums, 2021.

    Abstract: Featherwork is one of the most remarkable categories of material culture produced by Brazilian indigenous peoples due to its technical qualities and aesthetic beauty. Weapons, baskets, and musical instruments are frequently decorated with feathers, which are also used in body adornments that, in addition to their aesthetic purpose, are intended to convey information about the wearer, their position within a group, and the cultural values that they wish to transmit. The preservation of this type of artifacts is demanding given the biological cycle of the organic materials that compose them, which are inevitably subject to various stages of deterioration. In addition to the damage resulting from their use and perishable materials, these ethnographic objects are exposed to a new environment when they are incorporated into museum collections, where their existence must be prolonged. Since Brazil’s tropical climate often leads to pest proliferation, their degradation can be exacerbated by the action of insects such as moths and microorganisms such as fungi with irreversible consequences, making their conservation a daily challenge. Although the art of featherwork is still practiced by indigenous communities, the scarce supply of raw materials and contact with the tribes involved has reduced the scale of production. The preservation of this material heritage is thus very important, particularly in ethnographic museums. The use of gamma radiation for the disinfestation of cultural heritage artifacts and archived materials has been shown to be a safe process and an excellent alternative to traditional methods, which usually involve toxic chemical pesticides. Ionizing radiation has been used for more than 40 years and, since 2004, the Multipurpose Irradiator at the Institute of Energy and Nuclear Research (IPEN), a pioneering technology developed in Brazil, has made its application to cultural heritage a reality. With more than 20,000 cultural artifacts irradiated, IPEN is currently the national and international reference center for the use of radiation technology applied to the preservation of cultural heritage collections. Several studies have been conducted to determine the optimal dose required to eliminate contamination by biological agents in organic materials such as wood, leather, and feathers.A maximum dose of 10 kGy is recommended for featherwork in order to avoid affecting the physical and chemical properties of this type of material. This poster reports on the results of the effects of ionizing radiation on the color and morphological properties of a featherwork from the Museum of Archaeology and Ethnology at the University of São Paulo (MAE/USP). Samples of feathers were selected and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility, applying absorbed doses of between 0.5 and 200 kGy. The samples were chosen according to the color of the feathers and then photographed and analyzed using colorimetry based on the CIELAB 1976 color space scale before and 48 hours after irradiation and scanning electron microscopy. There were no significant changes in morphological and color properties within the disinfestation range applied.

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  • IPEN-DOC 24168

    SANTOS, PAULO de S. ; VASQUEZ, PABLO A.S. . C-188 CO-60 sources installation and source rack loading optimization processes in a gamma irradiation facility. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE, October 22-27, 2017, Belo Horizonte, MG. Proceedings... Rio de Janeiro, RJ: Associação Brasileira de Energia Nuclear, 2017.

    Abstract: Since 2004, the Multipurpose Gamma Facility at the Nuclear and Energy Research Institute has been providing services on radiation processing for disinfection and sterilization of health care and disposable medical products as well to support research studies on modification of physical, chemical and biological properties of several materials. Recently, there was an increment in irradiation of the Cultural Heritages. This facility uses C-188 double-encapsulated radioactive Cobalt-60 sources kwon as pencils from manufactures outside of country. The activity of the cobalt sources decays into a stable nickel isotope with a half-life around 5.27 years, which means a loss of 12.3% annually. Then, additional pencils of Cobalt-60 are added periodically to the source rack to maintain the required capacity or installed activity of the facility. The manufacturer makes shipping of the radioactive sources inside a high density container type B(U) , by sea. This one involves many administrative, transport and radiation safety procedures. Once in the facility, the container is opened inside a deep pool water to remove the pencils. The required source geometry of the facility is obtained by loading these source pencils into predetermined diagram or positions in source modules and distributing these modules over the source rack of the facility. The dose variation can be reduced placing the higher activity source pencils near the periphery of the source rack. In this work are presented the procedures for perform the boiling leaching tests applied to the container, the Cobalt-60 sources installation, the loading processes and the source rack loading optimization.

    Palavras-Chave: cobalt 60; gamma radiation; leaching; loading; nuclear materials management; radiation sources; sealed sources; security

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  • IPEN-DOC 27766

    VASQUEZ, PABLO A.S. ; NAGAI, MARIA L.E. . A contribuição da tecnologia de ionização gama na recuperação de acervos do patrimônio cultural / The contribution of gamma ionization technology to the recovery of cultural heritage collections. Revista do Arquivo, v. 6, n. 11, p. 101-110, 2020.

    Abstract: Os bens culturais materiais estão sujeitos a fatores de deterioração que afetam a legibilidade, a integridade física e a longevidade dos materiais. Controlar a contaminação por insetos e fungos, principalmente em materiais de origem orgânica, é um desafio para os conservadores, pois a biodeterioração acontece de forma veloz. Neste caso, ações de conservação devem ser tomadas imediatamente para estabilizar os danos e cessar a deterioração para que a contaminação não se espalhe pelos acervos. Este artigo pretende demonstrar que a ionização gama é uma opção eficiente e segura para eliminar insetos e fungos nos objetos do patrimônio cultural. Dentre as vantagens da aplicação da técnica, destacam-se: capacidade, tempo de processamento, tecnologia segura, dispensa de quarentena, ausência de impactos à saúde e ao meio ambiente. Os exemplos de aplicação da ionização gama em bens culturais físicos demonstram a eficácia e a viabilidade do processo para a preservação do patrimônio cultural.

    Palavras-Chave: gamma radiation; ionizing radiations; cultural objects; historical aspects; preservation; sterilization; fungi; insects; libraries

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  • IPEN-DOC 12023

    TETZNER, GUARACIABA de C.; HAMADA, MARGARIDA M. ; MADI FILHO, TUFIC ; VASQUEZ, PABLO A.S. ; RELA, PAULO R. ; CALVO, WILSON A.P. ; MESQUITA, CARLOS H. . Description of two tomography systems developed at IPEN-CNEN/SP. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 8th/ MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 15th, Sept. 30 - Oct. 5, 2007, Santos, SP. Proceedings... Sao Paulo: ABEN, 2007, 2007.

    Palavras-Chave: cobalt 60; computerized simulation; computerized tomography; experimental data; image processing; m codes; nai detectors; phantoms; plastic scintillators; polypropylene; resolution

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  • IPEN-DOC 19428

    SANTOS, PAULO S.; FERNANDES, VAGNER ; ENOKIHARA, CYRO T. ; CALVO, WILSON A.P. ; VASQUEZ, PABLO A.S. . Development of an isotropic underwater device for color enhancement of gemstones. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 11th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 18th; MEETING ON NUCLEAR INDUSTRY, 3rd, November 24-29, 2013, Recife, PE. Proceedings... Sao Paulo: ABEN, 2013, 2013.

    Palavras-Chave: brazil; quartz; minerals; color; gamma radiation; underwater operations; pool type reactors; brazilian cnen; cobalt 60

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  • IPEN-DOC 27207

    CASSARES, MARCELLA; SAKOTANI, NATALIA L.; KUNIGK, LEO; VASQUEZ, PABLO A.S. ; JURKIEWICZ, CYNTHIA. Effect of gamma irradiation on shelf life extension of fresh pasta. Radiation Physics and Chemistry, v. 174, p. 1-8, 2020. DOI: 10.1016/j.radphyschem.2020.108940

    Abstract: The feasibility of extending shelf life of fresh pasta using gamma radiation was evaluated. Microbiological quality and technological and sensorial properties were determined. Commercial gnocchi without chemical preservative was irradiated at doses of 5, 10 and 13 kGy and stored at 7, 15 and 25 °C during 90 days. The 13 kGy dose was effective in reducing the microbial count below the detection limit during storage at 25 °C. The growth of surviving psychrotrophic and mesophilic bacteria and molds and yeasts in pasta irradiated at 5 and 10 kGy was fitted to modified Gompertz and logistic models and kinetic parameters were determined. The gamma radiation did not change the cooking loss but reduced significantly the water absorption. There was no significant difference in the overall impression between control and irradiated samples. Gamma irradiation technology has a great potential to preserve fresh pasta at room temperature for more than 90 days without compromising sensory properties.

    Palavras-Chave: gamma radiation; food; microorganisms; food processing; irradiation; bacteria; storage life

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  • IPEN-DOC 26550

    LIMA, LENI M.P.R. ; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. . Effect of ionizing radiation on the color of botanical collections: exsiccata. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: Conservation and preservation methods are essential to maintain the wholeness of botanical collections specially for dried herbarium specimens also known as exsiccates, usually referring to a set of identified specimens belonging to taxa and distributed among all herbaria around the world. These vegetal materials are subjected to fungal attack and insect pests threatening their entirety. In recent years, disinfection by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials with excellent results. In this work, the effects on color properties of exsiccates samples irradiated with gamma radiation from Co-60 with different absorbed doses were studied. The botanical pressed and dehydrated samples – exsiccates – were selected from the Dom Bento José Pickel Herbarium (SPSF), located at São Paulo (Brazil). Two exsiccate samples were selected: SPSF-4021 and SPSF-08821. These samples come from Asteraceae and Solanaceae family and were collected in 1946 and 1984, respectively. Families of selected botanical collections are very susceptible to biodegradation. The irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN applying absorbed doses of 1 kGy, 6 kGy and 10 kGy. The selected ranged dose promotes insect disinfestation and fungal disinfection. Results were analyzed using colorimetry with CIELAB color space scale. Scanning electron microscopy were performed to analyze surface topography and elemental structure modifications by ionizing radiation and characterize the non-irradiated (0 kGy) and the effective disinfected (10 kGy) exsiccata samples. The results revealed no significant changes on colorimetric morphological properties of then irradiated samples. The color changes between the non-irradiated samples and the irradiated sample at the high absorbed dose are perceptible, but acceptable considering the adopted scale. The microscopy images of the non-irradiated and 10 kGy irradiated samples did not show significant differences in the topographic morphology of the exsiccata samples. The results obtained corroborate the studies of the application of gamma radiation to preserve materials of cellulosic origin. Subsequently and for continuity of this research, other samples will be analyzed.

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  • IPEN-DOC 26542

    VIEIRA, ANA C.D.; KODAMA, YASKO ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. . Effect of ionizing radiation on the color of featherwork. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: Featherwork collections are usually stored and managed by ethnographic museums. Even though the featherwork manufacturing is still practiced by the indigenous communities, the offer of raw material and the contact with the surrounding society ended up reducing the production scale of such objects. Consequently, the preservation of the culture heritage is very important, particularly in museums. Biodegradation can affect featherworks mainly by xylophagous insects and moths’ action. The tropical Brazilian weather contributes to the contamination and proliferation of insects and fungi making the preservation conditions difficult. The use of gamma radiation for the disinfection of cultural heritage objects and archived materials has shown to be a safe process and an excellent alternative to traditional methods usually involving high persistent and toxic chemical pesticides. In this work are presented the preliminary results of the ionizing radiation effects on the color and morphological properties of a featherwork from the Museum of Archeology and Ethnology of the University of São Paulo (MAE/USP). Samples of feathers were selected from the artifact and irradiated with gamma rays at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses between 0.5 kGy to 200 kGy. Samples were firstly chosen according to feather colors, photographed and analyzed using colorimetry with CIELAB 1976 color space scale and scanning electron microscopy (SEM), just after and 48 hours after the irradiation process. The results shown had no significant changes on color and morphological properties within the disinfection absorbed dose range applied.

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  • IPEN-DOC 29099

    LIMA, LENI M.P.R. ; KODAMA, YASKO ; BAITELLO, JOAO B.; OTUBO, LARISSA ; SANTOS, PAULO de S. ; VASQUEZ, PABLO A.S. . Effects of ionizing radiation decontamination on botanical collections in herbaria. Radiation Physics and Chemistry, v. 202, p. 1-8, 2023. DOI: 10.1016/j.radphyschem.2022.110561

    Abstract: Herbaria collections are very sensitive to attacks from microorganisms and insects. Therefore, preservation strategies and appropriate treatments are essential to manage these artifacts. Decontamination by ionizing radiation has become an effective strategy to preserve cultural heritage objects and archived materials, achieving excellent results. Therefore, this work aimed to study the effects of Co-60 gamma radiation on botanical collections. To accomplish this, samples of exsiccates, including botanical pressed and dehydrated specimens from Asteraceae and Solanaceae families, collected on diferentes dates were selected from the Dom Bento José Pickel Herbarium (SPSF), located in São Paulo (Brazil). Irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN, applying absorbed doses of 1 kGy, 6 kGy and 10 kGy. Gamma radiation effect was analyzed using colorimetry with CIELAB color space scale, scanning electron microscopy (SEM) and attenuated total reflectance with Fourier transform infrared (ATR-FTIR) spectroscopy. Results showed no significant colorimetric changes, or changes in the morphological properties of samples, indicating that this decontamination method can be used as an alternative treatment to eliminate insects and micro-fungi of botanical collections without the use of toxic substances.

    Palavras-Chave: gamma radiation; cultural objects; cultural objects; decontamination; preservation; plants; herbs; absorbed radiation doses; radiation effects

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  • IPEN-DOC 21001

    SANTOS, PAULO S.; VASQUEZ, PABLO A.S. . Effects of the interruption of the irradiation process on PMMA harwell industry dosimetry systems. In: INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE; MEETING ON NUCLEAR APPLICATIONS, 12th; MEETING ON REACTOR PHYSICS AND THERMAL HYDRAULICS, 19th; MEETING ON NUCLEAR INDUSTRY, 4th, October 4-9, 2015, São Paulo, SP. Proceedings... 2015.

    Palavras-Chave: radiation effects; pmma; dosemeters; ionizing radiations; irradiation

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  • IPEN-DOC 27825

    NAGAI, MARIA L.E. ; SANTOS, PAULO de S. ; OTUBO, LARISSA ; OLIVEIRA, MARIA J.A. ; VASQUEZ, PABLO A.S. . Gamma and electron beam irradiation effects for conservation treatment of cellulose triacetate photographic and cinematographic films. Radiation Physics and Chemistry, v. 182, p. 1-10, 2021. DOI: 10.1016/j.radphyschem.2021.109395

    Abstract: Photographic and cinematographic films of cellulose triacetate safeguarded in historical and cultural institutions are often contaminated by fungi when stored in inadequate conditions of humidity and temperature. The presence of fungi affects the image contained in the films, accelerates the process of biodeterioration and represents a risk to the health of people working with contaminated materials. In addition, another common physicochemical degradation affecting cellulose triacetate films causing deacetylation of polymer chain is called “vinegar syndrome”. Considering the dose interval established for the disinfection of cultural heritage materials, in this work the effects of irradiation with gamma rays and electron beam on photographic and cinematographic films of cellulose triacetate were evaluated. Additionally, the thermal stability behavior of the films and the feasibility of crosslinking of CTA films were investigated. Film samples were selected and characterized by FTIR-ATR spectroscopy. Irradiated samples by gamma rays and electron beam with radiation absorbed doses between 6 kGy and 200 kGy were examined by FEGSEM microscopy, UV–Vis spectrophotometry and differential scanning calorimetry (DSC). The results showed that disinfection by gamma and electron beam irradiation, in the dose range of 6 kGy–10 kGy, does not change or modification of main properties of the constitutive materials of photographic and cinematographic films. The applied dose of 50 kGy, both gamma rays and electron beam, indicated a crosslinking effect on the films and can be considered a possibility for the treatment of films affected by the “vinegar syndrome”.

    Palavras-Chave: photographic films; cinematography; cultural resources; electron beams; gamma radiation

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  • IPEN-DOC 16788

    VASQUEZ, PABLO A.S. ; COSTA, FABIO E. ; RELA, PAULO R. ; CALVO, WILSON A.P. ; LE ROUX, GALO A.C.; HAMADA, MARGARIDA M. . Gamma scanning evaluation for random packed columns. In: NUCLEAR SCIENCE SYMPOSIUM/MEDICAL IMAGING CONFERENCE, October 23-29, 2005, Fajardo, PR. Proceedings... 2005. p. 519-523.

    Palavras-Chave: hydrodynamics; liquids; distribution; column packing; distillation; gamma radiation; technetium 99

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  • IPEN-DOC 14922

    CALVO, WILSON A.P. ; HAMADA, MARGARIDA M. ; SPRENGER, FRANCISCO E. ; VASQUEZ, PABLO A.S. ; RELA, PAULO R. ; MARTINS, JOAO F.T.; PEREIRA, JOAO C.S. de M.; OMI, NELSON M. ; MESQUITA, CARLOS H. de . Gamma-ray computed tomography SCANNERS for applications in multiphase system COLUMNs. Nukleonika, v. 54, n. 2, p. 129-133, 2009.

    Palavras-Chave: porosity; gamma radiation; radiation sources; performance; materials testing; radiation detectors; computerized tomography

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  • IPEN-DOC 19957

    MESQUITA, CARLOS H. de ; CARVALHO, DIEGO V. de S.; KIRITA, RODRIGO; VASQUEZ, PABLO A.S. ; HAMADA, MARGARIDA M. . Gas-liquid distribution in a bubble column using industrial gamma-ray computed tomography. Radiation Physics and Chemistry, v. 95, p. 396-400, 2014.

    Palavras-Chave: brazilian cnen; laboratories; computerized tomography; industrial radiography; bubbles; distribution; gases; multiphase flow

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  • IPEN-DOC 27727

    OLIVEIRA, MARIA J.A. de ; VILLEGAS, GETHZEMANI M.E.; MOTTA, FLAVIA D.; FABELA-SANCHEZ, OMAR; ESPINOSA-ROA, ARIAN; FOTORAN, WESLEY L.; PEIXOTO, JANAINA C.; TANO, FABIA T.; LUGAO, ADEMAR B. ; VASQUEZ, PABLO A.S. . Influence of gamma radiation on Amphotericin B incorporated in PVP hydrogel as an alternative treatment for cutaneous leishmaniosis. Acta Tropica, v. 215, p. 1-8, 2021. DOI: 10.1016/j.actatropica.2020.105805

    Abstract: Amphotericin B (Amph-B) is an antifungal drug used intravenously for the treatment of leishmaniasis. Side-effects from Amph-B treatment can arise such as cardiac arrhythmia and renal dysfunctions, which will lead to discontinuation of treatment. Unfortunately, patients in endemic countries do not have access to alternative therapies. The objective of this study was to analyze the effects of Cobalt-60 gamma irradiation on crosslinking polymeric hydrogels (Hydg) and the incorporation of Amph-B into the gel as a controlled-release drug delivery alternative. Polyvinylpyrrolidone (PVP)/Amph-B solutions were irradiated with 15 kGy at 0 °C and 25 °C. The drug's stability was ascertained by UV–visible spectrometry, liquid chromatography/mass spectrometry and proton nuclear magnetic resonance. Irradiated Hydg/Amph-B achieved similar stability to the standard Amph-B solution and was enough to promote hydrogel crosslinking. In vitro trials were carried out to ensure Amph-B was still biologically active after irradiation. The results from flow cytometry and MTT assay show that Amph-B had an IC50 = 16.7 nM. A combination of Hydg at 1.324 gmL−1 and Amph-B at 25.1 nM for 24 h lead to the greatest inhibition of L. amazonensis promastigotes, and could be used as an alternative treatment method for cutaneous leishmaniosis.

    Palavras-Chave: antimicrobial agents; gamma radiation; hydrogels; drugs; delivery; parasitic diseases; irradiation

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  • IPEN-DOC 26551

    NAGAI, MARIA L.E.; SANTOS, PAULO S. ; OTUBO, LARISSA ; OLIVEIRA, MARIA J.A. de ; VASQUEZ, PABLO A.S. . Ionizing radiation for the preservation and conservation of photographic and cinematographic films. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: The Nuclear and Energy research Institute – IPEN-CNEN/SP through the Multipurpose Gamma Irradiation Facility has treated several bibliographical collections of Sao Paulo University-USP for disinfestation and disinfection of contaminated materials with insects and fungi. In this sense, gamma radiation from cobalt-60 is an excellent alternative tool to the traditional preservation process mainly because the biocidal action. Disinfection using gamma radiation for cultural heritage materials has been widely applied around the world in the last decades. Adequate storage of photographic and cinematographic materials is a challenge for conservation experts from preservation institutions. Contamination by fungi is one of leading causes of problem in this kind of collections. In addition, another common physicochemical degradation affecting cellulose triacetate films causing deacetylation of polymer chain is called “vinegar syndrome”. In this work are presented results of effect of ionizing radiation on photographic and cinematographic films. Selected films were characterized by FTIR-ATR spectroscopy and FEGSEM-EDS microscopy. Samples were irradiated by gamma rays with absorbed dose between 2 kGy and 200 kGy. Irradiated samples were analyzed by UV-vis spectrophotometry, FEGSEM, thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Results showed that disinfection by gamma rays can be achieved safely applying radiation absorbed doses between 6 kGy and 10 kGy with no change or modification of main properties of the constitutive polymeric materials. Gamma rays due to the effect of crosslinking is presented as an alternative to treat films affected by “vinegar syndrome” applying absorbed dose of 50 kGy in order to increase shelf life of cultural heritage materials.

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  • IPEN-DOC 26553

    KODAMA, YASKO ; RODRIGUES JUNIOR, ORLANDO ; GARCIA, RAFAEL H.L. ; OTUBO, LARISSA ; SANTOS, PAULO S. ; VASQUEZ, PABLO A.S. . Kinetics of Free Radicals Decay Reactions in Cellulosic Based Heritage Materials Disinfected by Gamma Radiation. In: VASQUEZ, PABLO A.S. (Ed.); NAGAI, MARIA L.E. (Coord.) INTERNATIONAL SYMPOSIUM ON GAMMA IONIZATION: TECHNOLOGY FOR PRESERVATION OF CULTURAL HERITAGE, 1st, October 25, 2019, São Paulo, SP. Abstract... São Paulo, 2019.

    Abstract: In this study, contemporary paper samples were irradiated using gamma radiation from Co-60 with different absorbed doses. The absorbed dose range was chosen taking into account the effective values to promote insect eradication, fungal disinfection and sterilization. The kinetics of decay of the cellulose free radicals induced by irradiation was analyzed using Electron Paramagnetic Resonance. Several spectra were obtained at room temperature for each applied absorbed dose immediately after irradiation as reference measurements. In order to understand the decay process of free radicals, additional spectra were obtained for different decay times up to almost 50 days after irradiation. De-noising treatment of the original obtained spectra signals were performed using wavelets. By integrating the electron paramagnetic resonance curves were calculated the area values and correlated to concentration, it is equivalent to spin concentration. Comparison of spectra was done by normalization of calculated area corresponding to cellulose spin concentration, considering the first measurement after irradiation as 100%. Further analyses and calculations were made to study the half-life and the kinetics models of the free radicals created. X-ray diffraction was carried out to identify crystalline phases and the effect of ionizing radiation on the crystalline structure of cellulose in paper. Scanning electron microscopy and Scanning Electron Microscopy Energy Dispersive Spectrometry were performed to analyze structure modifications by ionizing radiation, identifying cellulose fiber agglomeration zones and to quantify chemical elements. Likewise, samples were analyzed by infrared spectroscopy to determinate changes on the carbonyl groups. Results shown that for sterilization dose, 80% of the cellulose free radicals induced by ionizing radiation disappear in almost 40 days and for disinfection dose in 8 days. It can be concluded that if no significant modifications (side-effects) appear in the irradiated material after the radical decay time, the material will stay stable for the remaining lifetime. Proposed method using electron paramagnetic resonance results showed suitably to study the behavior of radicals on cellulosic based cultural heritage materials.

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✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

✔ A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

✔ Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

✔ 95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.