PAULO DE SOUZA SANTOS

PAULO DE SOUZA SANTOS

Página do item completo

Resultados de Busca

Agora exibindo 1 - 10 de 15

Gamma radiation processing for disinfection of a 19th century photo album
2021 - NAGAI, M.L.E.; SANTOS, P.S.; PARRON, I.; LEE, F.M.; VASQUEZ, P.
Effect of ionizing radiation on the color of botanical collections - exsiccata
2021 - LIMA, L.M.P.R.; KODAMA, Y.; OTUBO, L.; SANTOS, P.S.; VASQUEZ, P.A.
Conservation and preservation strategies are essential to manage 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. Particularly, these collections are very sensitive to the attack of fungi and insects. 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 gamma radiation on exsiccates samples were studied. Thus, two exsiccates, botanical pressed and dehydrated samples were selected from the Dom Bento José Pickel Herbarium (SPSF), situated at São Paulo (Brazil). These samples comes from Asteraceae and Solanaceae families and were collected in 1946 and 1984. The irradiation was performed at the Multipurpose Gamma Irradiation Facility at IPEN applying absorbed doses of 1 kGy, 6 kGy and 10 kGy, which are values of absorbed dose for disinfestation and disinfection. Results were analyzed using colorimetry with CIELAB color space scale and scanning electron microscopy. The results showed that there were no significant changes on colorimetric morphological properties of the samples.
Effect of ionizing radiation on the color of featherwork
2021 - DELGADO VIEIRA, A.C.; KODAMA, Y.; OTUBO, L.; SANTOS, P.S.; VASQUEZ SALVADOR, P.A.
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 material culture 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 has shown to be a safe process and an excellent alternative to traditional methods usually involving 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. The results shown had no significant changes on color and morphological properties within the disinfection absorbed dose range applied.
Irradiation protocol for cultural heritage conservation treatment
2021 - NAGAI, M.L.E.; SANTOS, P.S.; VASQUEZ, P.A.S.
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.
Effect of ionizing radiation on the color of featherwork
2019 - VIEIRA, ANA C.D.; KODAMA, YASKO; OTUBO, LARISSA; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
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.
Effect of ionizing radiation on the color of botanical collections
2019 - LIMA, LENI M.P.R.; KODAMA, YASKO; OTUBO, LARISSA; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
Conservation and preservation strategies are essential to manage 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. Particularly, these collections are very sensitive to the attack of fungi and insects. 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 gamma radiation on exsiccates samples were studied. Thus, six exsiccates, botanical pressed and dehydrated samples were selected from the Dom Bento José Pickel Herbarium (SPSF), situated at São Paulo (Brazil). Three of these samples comes from Asteraceae family and were collected in 1946, 1984 and 1986, while three other samples belong to Solanaceae family and were collected in 1953, 1984 and 2007. 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, which are values of absorbed dose for disinfestation and disinfection. Results were analyzed using colorimetry with CIELAB color space scale and scanning electron microscopy. The results showed that there were no significant changes on colorimetric morphological properties of the samples.
Irradiation protocol for cultural heritage conservation treatment
2019 - NAGAI, MARIA L.E.; SANTOS, PAULO de S.; VASQUEZ, PABLO A.
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 objective of the present study was the establishment of an efficient and reproducible model of an irradiation protocol for the treatment of cultural heritage materials in industrial irradiators. One of the main conditions of effective decontamination, resulting in the least possible deterioration of the materials due to the treatment, is the homogeneity of the mass of the materials to be treated. In this sense, it is important to establish and follow a protocol for the effective processing of ionizing radiation and to respect the ethical principles of conservation and restoration activities. The proposed protocol can also be applied to other types of files and collections. The decision to treat ionizing radiation should be conducted by professionals of conservation of cultural goods in agrément with professionals of the area of application of ionizing radiation. The objective of the protocol is to be a practical guide, from the detection of the problem to the final cleaning, so that conservatives and professionals of the irradiation can act in a collaborative and objective way to reach the objective of the treatment.
The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG
2019 - SOARES, J.J.S.; JACOVONE, R.M.S.; SANTOS, P.S.; ZAIM, M.H.; FARIA, D.L.A.; SAKATA, S.K.
Covalent functionalization of graphene oxide (GO) with polyethylene glycol (PEG) has been widely used in drug delivery systems. This nanocomposite exhibits excellent stability in the presence of high concentrations of salts and proteins and shows low toxicity compared to its raw form. However, it must be sterilized prior to use in medical devices, and for this purpose, the gamma irradiation shows a promising option. Sterilization by ionizing energy through gamma rays, generated by Cobalt-60 self-disintegration, consists in exposing the materials to short electromagnetic waves. The irradiation process provides substantial advantages when compared to thermal and chemical processes, such as, more precise control of the process, lower energy consumption, and less environmental pollution. In this work the effects of gamma radiation on GO and GO functionalized with amino-PEG (GO-PEG-NH2) irradiated with doses (15, 25, 35 and 50 kGy) at rate dose of 7.3 kGy.h-1 were evaluated. The analyses were performed by Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results showed that gamma radiation up to 50 kGy did not cause any defects on the nanomaterials.
Radioactive sealed sources production process for industrial radiography
2017 - SANTOS, PAULO de S.; NGUNGA, DANIEL M.G.; CAMARA, JULIO R.; VASQUEZ, PABLO A.S.
Since 1983, the Sealed Source Production Laboratory at the Nuclear and Energy Research Institute has been providing products and services to the private and governmental Brazilian users of industrial radiography and nucleonic control systems. Radioactive sealed sources are commonly used in nondestructive tests as radiography to make inspections and verify the internal structure and integrity of materials and in nucleonic gauges to control level, density, viscosity, etc. in on-line industrial processes. One of the most important activities carried out by this laboratory is related to the inspection of source projectors devices used in industrial radiography and its constituent parts as well as remote handle control assembly drive cable and guide tube systems. The laboratory also provide for the users iridium-192, cobalt-60 and selenium-75 sealed sources and performs quality control tests replacing spent or contaminated radiative sources. All discard of radioactive source is treated as radioactive waste. Additionally, administrative and commercial processes and protocols for exportation and transport of radioactive material are developed by specialized departments. In this work are presented the mean processes and procedures used by the Sealed Source Production Laboratory such as the arrival of the radioactive material to the laboratory and the source projectors, mechanical inspections, source loading, source leaking tests, etc.
The effect of gamma radiation on the structure of graphene oxide and graphene oxide functionalized with amino-PEG
2017 - SOARES, JAQUELINE J.S.; JACOVONE, RAYNARA M.S.; SANTOS, PAULO S.; ZAIM, MARCIO H.; FARIA, DALVA L.A. de; SAKATA, SOLANGE K.
The functionalization of graphene oxide (GO) with polyethylene glycol (PEG) has been widely used in drug delivery systems. This nanocomposite exhibits excellent stability in the presence of high concentrations of salts and proteins and shows to be less toxic than its raw form in vitro and in vivo. However, it must be sterilized before use in the medical field and the gamma irradiation shows a promising option for this purpose. Sterilization by ionizing energy through gamma rays, generated by Cobalt-60 self-disintegration, consists in exposing the materials to short electromagnetic waves. The irradiation process provides substantial advantages when compared to thermal and chemical processes such as more precise control of the process, production of products with superior qualities, lower energy consumption and less environmental pollution. In this work the effect of gamma radiation on the structure of GO and GO functionalized com Amino-PEG (GO-PEG-NH2) irradiated with different doses (15, 25, 35 and 50 kGy) and rate dose 7.31 kGy.h-1 was evaluated. The analyses were performed by Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results showed that the methods for the synthesis of GO and GO-PEG-NH2 was effective since there was confirmation of the surface oxidation of materials and functionalization with the PEG-NH2 and the sterilization by gamma radiation does not caused any defects on materials.