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1.
In Vivo ; 36(3): 1203-1221, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35478105

RESUMO

BACKGROUND/AIM: Melatonin (N-acetyl-5-methoxytryptamine), a chief secretory molecule of the pineal gland, has multiple properties, and numerous clinical investigations regarding its actions are in progress. This study investigated the radiomitigative role of melatonin in C57BL/6 mice. MATERIALS AND METHODS: Melatonin (100 mg/kg) was orally administered once daily starting at 1 h on day 1 and subsequently every 24 h until day 7 after whole-body irradiation (WBI) and survival was monitored for 30 days. The bone marrow, spleen, and intestine were studied to evaluate the mitigative potential of melatonin after radiation-induced damage. RESULTS: Melatonin significantly improved the survival upto 60% and 90% after 9 Gy (lethal) and 7.5 Gy (sub-lethal) WBI, respectively. Melatonin alleviated WBI-induced myelosuppression and pancytopenia, and increased white blood cell, red blood cell, platelet, and lymphocyte (CD4+ and CD8+) counts in peripheral blood. Bone marrow and spleen cellularity were restored through enhanced haematopoiesis. Melatonin ameliorated the damage in the small intestine, and promoted recovery of villi length, crypts number, and goblet cell count. CONCLUSION: Melatonin mitigates the radiation-induced injury in the gastrointestinal and haematopoietic systems. The observed radiomitigative properties of melatonin can also be useful in the context of adjuvant therapy for cancer and radiotherapy.


Assuntos
Melatonina , Lesões por Radiação , Protetores contra Radiação , Adjuvantes Imunológicos , Animais , Raios gama , Melatonina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Protetores contra Radiação/farmacologia , Irradiação Corporal Total/efeitos adversos
2.
Methods Mol Biol ; 2484: 143-159, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35461451

RESUMO

Induced mutations have been used to facilitate plant breeding for more than 80 years. Success requires the development of a mutant population and methods to evaluate that population. In this protocol we provide methods for the development of a chickpea mutant population using gamma irradiation, and low-cost methods for the molecular characterization of the mutant population. Specifically, this chapter provides detailed methods for (1) mutation induction by gamma rays and determination of LD50 and RD50, (2) phenotypic assessment of the M2 generation, (3) low-cost extraction of genomic DNA, and (4) identification of induced mutations using low-cost agarose-gel based TILLING. The methods are low-cost and designed to be applicable in most research settings.


Assuntos
Cicer , Cicer/genética , Raios gama/efeitos adversos , Mutação , Melhoramento Vegetal
3.
Sci Rep ; 12(1): 7012, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35488046

RESUMO

In the recent years, huge efforts have been conducted to conceive a cost-effective production process of the bacterial nanocellulose (BNC), thanks to its marvelous properties and broadening applications. Herein, we unveiled the impact of gamma irradiation on the BNC yield by a novel bacterial strain Komagataeibacter hansenii KO28 which was exposed to different irradiation doses via a designed scheme, where the productivity and the structural properties of the BNC were inspected. After incubation for 240 h, the highest BNC yield was perceived from the culture treated twice with 0.5 kGy, recording about 475% higher than the control culture. Furthermore, almost 92% of its BNC yield emerged in the first six days. The physicochemical characteristics of the BNCs were investigated adopting scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Additionally, the water holding capacity, water release rate, surface area (BET), and mechanical properties were configured for the BNC generated from the control and the irradiated cultures. As a whole, there were no significant variations in the properties of the BNC produced by the irradiated cultures versus the control, proposing the strain irradiation as a valuable, facile, and cheap route to augment the BNC yield.


Assuntos
Celulose , Água , Celulose/química , Raios gama , Difração de Raios X
4.
Int J Mol Sci ; 23(8)2022 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-35456987

RESUMO

Exosomes released by irradiated cells mediate the radiation-induced bystander effect, which is manifested by DNA breaks detected in recipient cells; yet, the specific mechanism responsible for the generation of chromosome lesions remains unclear. In this study, naive FaDu head and neck cancer cells were stimulated with exosomes released by irradiated (a single 2 Gy dose) or mock-irradiated cells. Maximum accumulation of gamma H2A.X foci, a marker of DNA breaks, was detected after one hour of stimulation with exosomes from irradiated donors, the level of which was comparable to the one observed in directly irradiated cells (a weaker wave of the gamma H2A.X foci accumulation was also noted after 23 h of stimulation). Exosomes from irradiated cells, but not from control ones, activated two stress-induced protein kinases: ATM and ATR. Noteworthy is that while direct irradiation activated only ATM, both ATM and ATR were activated by two factors known to induce the replication stress: hydroxyurea and camptothecin (with subsequent phosphorylation of gamma H2A.X). One hour of stimulation with exosomes from irradiated cells suppressed DNA synthesis in recipient cells and resulted in the subsequent nuclear accumulation of RNA:DNA hybrids, which is an indicator of impaired replication. Interestingly, the abovementioned effects were observed before a substantial internalization of exosomes, which may suggest a receptor-mediated mechanism. It was observed that after one hour of stimulation with exosomes from irradiated donors, phosphorylation of several nuclear proteins, including replication factors and regulators of heterochromatin remodeling as well as components of multiple intracellular signaling pathways increased. Hence, we concluded that the bystander effect mediated by exosomes released from irradiated cells involves the replication stress in recipient cells.


Assuntos
Efeito Espectador , Exossomos , Efeito Espectador/efeitos da radiação , Linhagem Celular Tumoral , Exossomos/metabolismo , Raios gama , Transdução de Sinais/efeitos da radiação
5.
Sci Rep ; 12(1): 5878, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35393518

RESUMO

In studies on the mechanism of DNA damage response where ionizing radiation is used as the DNA damaging agent, cells are often exposed to ionizing radiation on melting ice (corresponding to 0.8 °C). The purpose of this procedure is to inhibit cellular processes i.e. DNA repair. Low temperature at exposure has been shown to act in a radioprotective manner at the level of cytogenetic damage, but its mechanisms of action are poorly understood. The aim of the study was to analyze the effect of hypothermia at the level of formation and decay of NBS1, γH2AX, and 53BP1 foci, micronuclei, survival, cell cycle progression and oxidative stress in U2OS cells. The results show that hypothermia alone induced oxidative stress and foci. When applied in combination with radiation but only during the exposure time, it potentiated the formation of γH2AX and 53BP1 but not of NBS1 foci. When applied during irradiation and subsequent repair time, 53BP1 and NBS1 foci formed and decayed, but the levels were markedly lower than when repair was carried out at 37 °C. The frequency of micronuclei was elevated in cells irradiated at 0.8 °C, but only when analysed 20 h after irradiation which is likely due to a reduced G2 cell cycle block. Hypothermia reduced cell survival, both with and without radiation exposure. The temperature effect should be considered when cooling cells on melting ice to inhibit DNA repair in the induction of DNA damage.


Assuntos
Hipotermia , Dano ao DNA , Reparo do DNA , Raios gama/efeitos adversos , Histonas/metabolismo , Humanos , Gelo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo
6.
PLoS One ; 17(3): e0265281, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35286349

RESUMO

PURPOSE: The aim of this study was to explore the effects of chronic low-dose-rate gamma-radiation at a multi-scale level. The specific objective was to obtain an overall view of the endothelial cell response, by integrating previously published data on different cellular endpoints and highlighting possible different mechanisms underpinning radiation-induced senescence. MATERIALS AND METHODS: Different datasets were collected regarding experiments on human umbilical vein endothelial cells (HUVECs) which were chronically exposed to low dose rates (0, 1.4, 2.1 and 4.1 mGy/h) of gamma-rays until cell replication was arrested. Such exposed cells were analyzed for different complementary endpoints at distinct time points (up to several weeks), investigating cellular functions such as proliferation, senescence and angiogenic properties, as well as using transcriptomics and proteomics profiling. A mathematical model was proposed to describe proliferation and senescence. RESULTS: Simultaneous ceasing of cell proliferation and senescence onset as a function of time were well reproduced by the logistic growth curve, conveying shared equilibria between the two endpoints. The combination of all the different endpoints investigated highlighted a dose-dependence for prematurely induced senescence. However, the underpinning molecular mechanisms appeared to be dissimilar for the different dose rates, thus suggesting a more complex scenario. CONCLUSIONS: This study was conducted integrating different datasets, focusing on their temporal dynamics, and using a systems biology approach. Results of our analysis highlight that different dose rates have different effects in inducing premature senescence, and that the total cumulative absorbed dose also plays an important role in accelerating endothelial cell senescence.


Assuntos
Senescência Celular , Biologia de Sistemas , Células Cultivadas , Raios gama/efeitos adversos , Células Endoteliais da Veia Umbilical Humana , Humanos , Radiobiologia
7.
Mar Pollut Bull ; 178: 113593, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35344732

RESUMO

The distribution pattern of natural radionuclides (226Ra, 232Th, and 40K) and anthropogenic radionuclide (137Cs) in surface sediment samples from the southwestern coastline of the Caspian Sea were determined to estimate the radiation hazard indices using a high-purity germanium HPGe gamma-ray detector. The activity concentrations of the sediment samples ranged from 22.5 ± 1.0 to 47.4 ± 2.2 Bq kg-1 dry weight (dw) for 226Ra, 6.5 ± 0.1 to 18.7 ± 0.7 Bq kg-1 dw for 232Th, 559.9 ± 30.9 to 233.2 ± 19.4 Bq kg-1 dw for 40K, and 0.9 MDL (minimum detection limit) to 2.7 ± 0.1 Bq kg-1 dw for 137Cs. Based on the measured values, radiological risk indices were estimated. The mean values for absorbed dose rate, ambient dose equivalent rate, and excess lifetime cancer risk, were calculated as 35.7 nGy h-1, 47.9 nSv h-1, and 0.2, respectively.


Assuntos
Poluentes Radioativos do Solo , Mar Cáspio , Raios gama , Poluentes Radioativos do Solo/análise
8.
Sci Rep ; 12(1): 4299, 2022 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-35277556

RESUMO

Scaffolds used to receive stem cells are a promising perspective of tissue regeneration research, and one of the most effective solutions to rebuild organs. In the near future will be possible to reconstruct a natural tooth using stems cells, but to avoid an immune-defensive response, sterilize the scaffold is not only desired, but also essential to be successful. A study confirmed stem cells extracted from rat's natural teeth, and implanted into the alveolar bone, could differentiate themselves in dental cells, but the scaffold's chemistry, geometry, density, morphology, adherence, biocompatibility and mechanical properties remained an issue. This study intended to produce a completely sterilized dental scaffold with preserved extracellular matrix. Fifty-one samples were collected, kept in formaldehyde, submitted to partial demineralization and decellularization processes and sterilized using four different methods: dry heating; autoclave; ethylene-oxide and gamma-radiation. They were characterized through optical images, micro-hardness, XRD, EDS, XRF, SEM, histology and sterility test. The results evidenced the four sterilization methods were fully effective with preservation of ECM molecular arrangements, variation on chemical composition (proportion of Ca/P) was compatible with Ca/P proportional variation between enamel and dentine regions. Gamma irradiation and ethylene oxide presents excellent results, but their viability are compromised by the costs and technology's accessibility (requires very expensive equipment and/or consumables). Excepted gamma irradiation, all the sterilization methods more than sterilizing also reduced the remaining pulp. Autoclave presents easy equipment accessibility, lower cost consumables, higher reduction of remaining pulp and complete sterilization, reason why was considered the most promising technique.


Assuntos
Materiais Biocompatíveis , Óxido de Etileno , Animais , Matriz Extracelular , Raios gama , Temperatura Alta , Ratos , Esterilização/métodos
9.
Sci Rep ; 12(1): 3387, 2022 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-35233005

RESUMO

Radiological incidents or terrorist attacks would likely expose civilians and military personnel to high doses of ionizing radiation, leading to the development of acute radiation syndrome. We examined the effectiveness of prophylactic administration of a developmental radiation countermeasure, γ-tocotrienol (GT3), in a total-body irradiation (TBI) mouse model. CD2F1 mice received GT3 24 h prior to 11 Gy cobalt-60 gamma-irradiation. This dose of radiation induces severe hematopoietic acute radiation syndrome and moderate gastrointestinal injury. GT3 provided 100% protection, while the vehicle control group had 100% mortality. Two-dimensional differential in-gel electrophoresis was followed by mass spectrometry and Ingenuity Pathway Analysis (IPA). Analysis revealed a change in expression of 18 proteins in response to TBI, and these changes were reversed with prophylactic treatment of GT3. IPA revealed a network of associated proteins involved in cellular movement, immune cell trafficking, and inflammatory response. Of particular interest, significant expression changes in beta-2-glycoprotein 1, alpha-1-acid glycoprotein 1, alpha-2-macroglobulin, complement C3, mannose-binding protein C, and major urinary protein 6 were noted after TBI and reversed with GT3 treatment. This study reports the untargeted approach, the network, and specific serum proteins which could be translated as biomarkers of both radiation injury and protection by countermeasures.


Assuntos
Síndrome Aguda da Radiação , Protetores contra Radiação , Síndrome Aguda da Radiação/tratamento farmacológico , Animais , Cromanos , Raios gama/efeitos adversos , Glicoproteínas/uso terapêutico , Camundongos , Proteômica , Protetores contra Radiação/farmacologia , Protetores contra Radiação/uso terapêutico , Vitamina E/análogos & derivados , Irradiação Corporal Total
10.
Appl Radiat Isot ; 184: 110177, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35272230

RESUMO

Flexible pipes are modular constructions made up of several layers. They are broadly employed in oil & gas industry, playing an important role in the Brazilian Pre-Salt production. Under specific conditions, seawater can ingress and this contact with metallic middle layers can significantly lead to a service life reduction of these layers, especially due to a mechanism known as CO2 Stress Corrosion Cracking (SCC-CO2). Therefore, it becomes mandatory that inspection systems suitable for submarine use in order to detect annulus flooding before the failure of the flexible pipe become available. This paper presents an inspection system based on the gamma rays transmission focused on detecting such flood condition, possibly overcoming limitations of other inspection systems available in the market. The reliability of this solution was statistically evaluated as presented herein, showing great robustness based on the numerous available trials.


Assuntos
Dióxido de Carbono , Brasil , Corrosão , Raios gama , Reprodutibilidade dos Testes
11.
Appl Radiat Isot ; 184: 110117, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35272232

RESUMO

A low cost and easily implemented target system for neutron activation was developed that takes advantage of the neutron flux produced as a by-product during the cyclotron production of medical isotopes. Samples are placed in close proximity to an 18O(p,n)18F target on a cyclotron operating between 18 and 22 MeV for irradiation. Analysis of the samples by gamma spectroscopy shows that activation is proportional to the neutron exposure, and the mass of the element present in the sample.


Assuntos
Ciclotrons , Ouro , Raios gama , Nêutrons , Prata
12.
Health Phys ; 122(4): 480-487, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35244615

RESUMO

ABSTRACT: A shielded neutron irradiation facility has been constructed to contain a 74 GBq plutonium-beryllium neutron source at the University of Utah. Due to lack of information and recent use, the GEANT4 Monte Carlo Toolkit was used to perform dose assessments and validation of the designed shield and beam port for storage and operational geometries where the source was to be placed. Borated polyethylene was used as the primary shielding material with a lead-lined beam port to collimate neutrons and reduce gamma rays within the active beam profile. The lead lining was found to reduce the gamma-to-neutron ratio within the profile to 0.259 ± 0.001 and maintain an average neutron flux of 4,633.7 ± 10.2 n cm-2 s-1. The measured dose rate of the source at 30 cm from its constructed storage configuration was found to be 22.3 ± 1.1 µSv h-1 and in good agreement with simulated values. This was also close to the target rate of 20 µSv h-1, the public limit for whole-body dose accumulation, imposed on the design. Measurements of the source during its retrieval and placement into the shield show good agreement with the simulated results and provide a strong validation for the future use of the source in experiments at the University of Utah.


Assuntos
Berílio , Plutônio , Raios gama , Método de Monte Carlo , Nêutrons , Plutônio/análise
13.
Sensors (Basel) ; 22(6)2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35336450

RESUMO

Herein, we report the γ-ray ionizing radiation response of a commercial monolithic active-pixel sensor (MAPS) camera under strong-dose-rate irradiation with an online detection and monitoring system for strong radiation conditions. We present the first results of the distribution of three types of MAPS camera and establish a linear relationship between the average response signal and radiation dose rate in the strong-dose-rate range. There is an obvious response signal in the video frames when the camera module parameters are set to automatic, but the linear response is very poor. However, the fixed image parameters are not good at adapting to the changes of the environment and affect the quality of the video frames. A dual module online radiation detection and monitoring probe was made to carry out effective video monitoring and radiation detection at the same time. The measurement results show that the dose rate detection error is less than 5% with a dose rate in the range of 60 to 425 Gy/h, and the visible light image does not have obvious distortion, deformation, or color shift due to the interference of the radiation response event and radiation damage. Hence, the system test results show that it can be used for online detection and monitoring in a strong radiation environment.


Assuntos
Raios gama
14.
Anal Chim Acta ; 1202: 339686, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35341531

RESUMO

Boron is an important element in nuclear reactor technology due to its high neutron absorption cross section of 10B isotope. Isotopic composition of B (IC, 10B/11B atom ratio) determination in finished neutron absorbers is a necessity under chemical quality control (CQC). We report an innovative greener method for rapid and non-destructive approach of isotopic composition determination of B in "as received" boron based ceramic neutron absorbers including boron carbides and hexa-borides by external (in air) Particle Induced Gamma-ray Emission (PIGE) using 3.5 MeV proton beam. It involves irradiation of "as received" powder samples wrapped in a thin Mylar film and measurement of prompt gamma rays at 429, 718 and 2125 keV from 10B(p,αγ)7Be, 10B(p,p'γ)10B and 11B(p,p'γ)11B, respectively, using a HPGe detector system. The method was standardized with natural and enriched B4C powders. For validation, the results of isotopic composition obtained from "as received" samples were compared with that obtained from pellet samples using both external and vacuum chamber PIGE methods. IC values obtained for natural to 10B enriched samples (19.8-67 atom % of 10B) are very encouraging with 1-2% and 0.3-0.7% uncertainties from single and replicate sample experiments. The method is truly non-destructive as the samples can be returned back as such after the experiment as they are not radioactive. Compared to existing PIGE method for isotopic composition of B, the developed method keeps promise for wide applications as it is simple, sensitive and rapid and it does not require vacuum, pellet preparation with a binder, exact mass of the sample and beam current measurement.


Assuntos
Boro , Nêutrons , Cerâmica , Raios gama , Isótopos
15.
Int J Mol Sci ; 23(5)2022 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-35269835

RESUMO

The radioprotective effects of a new 1-isobutanoil-2-isopropylisothiourea derivative named T1082 are presented. Research methods included toxic characteristics, radioprotective activity (Till-McCulloch's test and 30-day survival test) in γ-ray total-body-irradiated mice, and a clinical and histological study of the effect of T1082 on acute radiation skin reactions (RSR) in rats after a single or fractionated ß-ray local irradiation. T1082 is more effective than its analogue, the NOS inhibitor T1023, at low concentrations and doses (1/12-1/8 LD10), both parenterally and intragastrically. In this case, its therapeutic index (LD50/ED50) reaches 30, and the optimal radioprotective doses (ED84-98-141-224 mg/kg) are an order less than the maximum tolerated doses-1/16-1/10 LD10. These properties allowed T1082, at a low intragastrical dose (160 mg/kg; 1/14 LD10), to significantly limit the severity of acute RSR after single (40 Gy) and fractionated (78 Gy) ß-ray irradiation. The results confirm T1082 as one of the safest emergency radioprotectors and indicate the prospects for its further development as a pharmacological agent for the prevention of RT complications.


Assuntos
Proteção Radiológica , Protetores contra Radiação , Animais , Raios gama , Dose Letal Mediana , Camundongos , Fosfatos , Protetores contra Radiação/farmacologia , Protetores contra Radiação/uso terapêutico , Ratos
16.
Appl Radiat Isot ; 184: 110198, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35313266

RESUMO

Periodic intermediate checks on the equipment used for calibration activity accredited for the conformity with the international norm ISO/IEC 17025 are an essential issue for monitoring the validity of calibration laboratory's results. These checks should be carried out according to a procedure defined by each accredited laboratory. The results of these checks should not exceed the acceptance criteria established in the laboratory and statistical techniques shall be applied to the reviewing of the results. In this work, a simple method of carrying out intermediate checks on working standards used for calibrations of ionizing radiation dosimeters in a 60Co gamma ray beam was presented. Moreover, the statistical analysis of obtained results was presented. This analysis allowed for a reliable inference regarding the operation of the working standards used to calibrate the customer's devices. The presented methods can be used as a guidance in order to conform to the ISO/IEC 17025 requirements for carrying out and reviewing of periodic intermediate checks results in the area of calibrations of ionizing radiation dosimeters for external beam radiotherapy.


Assuntos
Laboratórios , Dosímetros de Radiação , Calibragem , Raios gama
17.
Appl Radiat Isot ; 184: 110207, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35316779

RESUMO

This paper presents a detailed statistical analysis of experimental results of dynamic breakdown voltage and electrical breakdown time delay for xenon-filled diode. These quantities have a stochastic nature and they were measured in the cases when the xenon-filled diode was and was not exposed to a gamma radiation source, with exposure dose rate 7.7⋅10-12 C/(kg⋅s). The static breakdown voltage was estimated based on dynamic breakdown voltage as a function of voltage increase rate. The applicability of certain distributions to experimental dynamic breakdown voltage and electrical breakdown time delay data was also analyzed.


Assuntos
Xenônio , Raios gama
18.
Appl Radiat Isot ; 184: 110194, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35316780

RESUMO

The in-situ relative detection efficiency strongly influences the characteristics of the k0-based internal monostandard neutron activation analysis (IM-NAA). In the present work, various mathematical functions were explored for the establishment of in-situ relative detector efficiency calibration and compared their performance based on the reduced chi-square (χ2) values. Among the various mathematical functions, the polynomial logarithm with 6th order was found to be associated with the minimum mean standard deviation for the experimental data and the lowest value of reduced χ2 after carrying out multiple iterations using Nelder-Mead algorithm. Quality assurance of the function was tested by carrying out elemental quantification of the NIST SRM 1633b coal fly ash. Gamma energies of the activation products, 152mEu, 59Fe, 140La, 24Na and 46Sc of the irradiated NIST standard were used for the in-situ relative full energy peak efficiency calibration of 30% HPGe detector. The sample was counted for different time intervals for the complete profiling of the elements present in the NIST SRM. The deviations for most of the elements were found to be within ±5% with respect to the certified values and ξ-score values were within ±2, demonstrating its better accuracy. This method was also applied satisfactorily to profile the elemental concentrations of alloy materials used in a thermal sensor guide tube of the steam generator in a test reactor.


Assuntos
Análise de Ativação de Nêutrons , Calibragem , Raios gama , Análise de Ativação de Nêutrons/métodos
19.
Appl Radiat Isot ; 184: 110200, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35325648

RESUMO

In this study, graphitic carbon nitride quantum dots (g-C3N4QDs) were synthesized using different solvents, characterized, and then exposed to a gamma-ray source (137Cs) at irradiation doses of 0.1, 1.48, 2.05 and 3.25 Gy. The intensities of the emission bands progressively were attenuated as the received dose of gamma radiation increased. The changes were quantified with the help of a non-linear fit model. The material showed promising use as a dosimeter for low-dose radiation applications.


Assuntos
Grafite , Pontos Quânticos , Raios gama , Compostos de Nitrogênio
20.
Appl Radiat Isot ; 184: 110206, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35325649

RESUMO

Optical fiber is used as a tool for data transmission in radiation environments in many applications such as medical, plasma diagnostics, and space satellites. The optical transmission is affected by ionizing radiation, characterized by radiation-induced attenuation. This feature allows use as a dosimeter sensor. In this work, the gamma radiation responses of three types of single-mode and multi-mode fibers, with different dopants of erbium (Er), germanium (Ge), and phosphorus (P) were evaluated. Radiation-induced attenuation was measured by spectrophotometer in wavelength ranges of 400-700 nm. The Er-doped fiber had higher attenuation of 0.8 dB/m after 560 mGy total dose. There was a reasonable linear relationship between the amount of attenuation and absorbed dose in P-, Ge-, and Er-doped fibers.


Assuntos
Germânio , Fibras Ópticas , Érbio , Raios gama , Dosímetros de Radiação
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