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1.
Radiat Environ Biophys ; 63(2): 195-202, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38709277

RESUMEN

This study investigated natural sand thermoluminescence (TL) response as a possible option for retrospective high-dose gamma dosimetry. The natural sand under investigation was collected from six locations with selection criteria for sampling sites covering the highest probability of exposure to unexpected radiation on the Egyptian coast. Dose-response, glow curve, chemical composition, linearity, and fading rate for different sand samples were studied. Energy Dispersive X-ray Spectroscopy (EDX) analysis revealed differences in chemical composition among the various geological sites, leading to variations in TL glow curve intensity. Sand samples collected from Ras Sedr, Taba, Suez, and Enshas showed similar TL patterns, although with different TL intensities. Beach sands of Matrouh and North Coastal with a high calcite content did not show a clear linear response to the TL technique, in the dose range of 10 Gy up to 30 kGy. The results show that most sand samples are suitable as a radiation dosimeter at accidental levels of exposure. It is proposed here that for high-dose gamma dosimetry with doses ranging from 3 to 10 kGy, a single calibration factor might be enough for TL measurements using sand samples. However, proper calibration might allow dose assessment for doses even up to 30 kGy. Most of the investigated sand samples had nearly stable fading rates after seven days of storage. The Ras Sedr sands sample was the most reliable for retrospective dose reconstruction.


Asunto(s)
Arena , Dosimetría Termoluminiscente , Rayos gamma , Dosis de Radiación , Calibración
2.
Sci Rep ; 14(1): 11535, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38773159

RESUMEN

In this study, a novel method for the fabrication of hesperidin/reduced graphene oxide nanocomposite (RGOH) with the assistance of gamma rays is reported. The different RGOHs were obtained by varying hesperidin concentrations (25, 50, 100, and 200 wt.%) in graphene oxide (GO) solution. Hesperidin concentrations (25, 50, 100, and 200 wt.%) in graphene oxide (GO) were varied to produce the various RGOHs. Upon irradiation with 80 kGy from γ-Ray, the successful reduction of GO occurred in the presence of hesperidin. The reduction process was confirmed by different characterization techniques such as FTIR, XRD, HRTEM, and Raman Spectroscopy. A cytotoxicity study using the MTT method was performed to evaluate the cytotoxic-anticancer effects of arbitrary RGOH on Wi38, CaCo2, and HepG2 cell lines. The assessment of RGOH's anti-inflammatory activity, including the monitoring of IL-1B and IL-6 activities as well as NF-kB gene expression was done. In addition, the anti-invasive and antimetastatic properties of RGOH, ICAM, and VCAM were assessed. Additionally, the expression of the MMP2-9 gene was quantified. The assessment of apoptotic activity was conducted by the detection of gene expressions related to BCl2 and P53. The documentation of the JNK/SMAD4/MMP2 signaling pathway was ultimately accomplished. The findings of our study indicate that RGOH therapy has significant inhibitory effects on the JNK/SMAD4/MMP2 pathway. This suggests that it could be a potential therapeutic option for cancer.


Asunto(s)
Rayos gamma , Grafito , Hesperidina , Metaloproteinasa 2 de la Matriz , Nanocompuestos , Proteína Smad4 , Humanos , Grafito/química , Grafito/farmacología , Nanocompuestos/química , Hesperidina/farmacología , Hesperidina/química , Proteína Smad4/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/genética , Tecnología Química Verde/métodos , Transducción de Señal/efectos de los fármacos , Células CACO-2 , Células Hep G2 , Línea Celular Tumoral , MAP Quinasa Quinasa 4/metabolismo
3.
Sci Rep ; 14(1): 11524, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38773212

RESUMEN

The biological mechanisms triggered by low-dose exposure still need to be explored in depth. In this study, the potential mechanisms of low-dose radiation when irradiating the BEAS-2B cell lines with a Cs-137 gamma-ray source were investigated through simulations and experiments. Monolayer cell population models were constructed for simulating and analyzing distributions of nucleus-specific energy within cell populations combined with the Monte Carlo method and microdosimetric analysis. Furthermore, the 10 × Genomics single-cell sequencing technology was employed to capture the heterogeneity of individual cell responses to low-dose radiation in the same irradiated sample. The numerical uncertainties can be found both in the specific energy distribution in microdosimetry and in differential gene expressions in radiation cytogenetics. Subsequently, the distribution of nucleus-specific energy was compared with the distribution of differential gene expressions to guide the selection of differential genes bioinformatics analysis. Dose inhomogeneity is pronounced at low doses, where an increase in dose corresponds to a decrease in the dispersion of cellular-specific energy distribution. Multiple screening of differential genes by microdosimetric features and statistical analysis indicate a number of potential pathways induced by low-dose exposure. It also provides a novel perspective on the selection of sensitive biomarkers that respond to low-dose radiation.


Asunto(s)
Relación Dosis-Respuesta en la Radiación , Análisis de la Célula Individual , Análisis de la Célula Individual/métodos , Humanos , Método de Montecarlo , Radiometría/métodos , Línea Celular , Rayos gamma/efectos adversos
4.
Bull Exp Biol Med ; 176(5): 645-648, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38727954

RESUMEN

Using the method of dominant lethal mutations, we assessed the frequency of the death of Drosophila melanogaster embryos under combined exposure to ionizing γ-radiation and non-ionizing pulsed magnetic field at various doses and modes of exposure. Mutagenic effect of combined exposure is antagonistic in nature. The antagonism is more pronounced when the following mode of exposure was used: exposure to non-ionizing pulsed magnetic field for 5 h followed by exposure to γ-radiation at doses of 3, 10, and 60 Gy. In case of reverse sequence of exposures, the antagonistic effect was statistically significant after exposure to γ-radiation at doses of 3 and 10 Gy, whereas at a dose of 20 Gy, a synergistic interaction was noted.


Asunto(s)
Drosophila melanogaster , Rayos gamma , Animales , Drosophila melanogaster/efectos de la radiación , Drosophila melanogaster/genética , Rayos gamma/efectos adversos , Radiación Electromagnética , Relación Dosis-Respuesta en la Radiación , Campos Electromagnéticos/efectos adversos , Embrión no Mamífero/efectos de la radiación , Radiación Ionizante , Mutación/efectos de la radiación , Mutagénesis/efectos de la radiación
5.
Cell Biochem Funct ; 42(4): e4026, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38693631

RESUMEN

This work investigates the efficiency of cholecalciferol and low dose gamma radiation in modulating cytokine storm through their impact on inflammatory and anti-inflammatory cytokine and protecting against lung and liver injuries. Male Swiss albino mice were exposed to 0.2 Gy gamma radiation/week for four consecutive weeks then injected intraperitoneally (i.p) with a single dose of 8.3 × 106 CFU Escherichia coli/g b.w. then injected i.p. with 1.0 mg/kg cholecalciferol (Vit D3) for 7 days starting 4 h after E. coli injection. The results revealed that Cholecalciferol and low dose gamma radiation caused significant depletion in the severity of E. coli infection (colony forming unit per milliliter), log10 of E. coli, Tumor necrosis factor alpha, Interleukin 6, VEGF, alanine aminotransferase, and aspartate aminotransferase levels and significant elevation in IL-10, IL-4, and HO-1. Immunohistochemical analysis of caspase-3 expression in lung tissue section showed low caspase-3 expression in cholecalciferol and low dose gamma radiation treated group. Histopathological examinations were performed in both lung and liver tissues which also emphasis the biochemical findings. Our results exhibit the importance of cholecalciferol and low dose gamma radiation in improving liver function and providing anti-inflammatory response in diseases causing cytokine storm.


Asunto(s)
Colecalciferol , Infecciones por Escherichia coli , Escherichia coli , Rayos gamma , Animales , Ratones , Colecalciferol/farmacología , Masculino , Infecciones por Escherichia coli/tratamiento farmacológico , Infecciones por Escherichia coli/patología , Hígado/patología , Hígado/efectos de los fármacos , Hígado/metabolismo , Pulmón/patología , Pulmón/metabolismo , Citocinas/metabolismo , Síndrome de Liberación de Citoquinas/patología , Síndrome de Liberación de Citoquinas/tratamiento farmacológico , Síndrome de Liberación de Citoquinas/etiología , Aspartato Aminotransferasas/sangre
6.
Chemosphere ; 357: 141915, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38582162

RESUMEN

Standard OECD tests are used to generate data on biodegradation (OECD 307) and sorption (OECD 106) of test chemicals in soil. In such tests, data on abiotic degradation using sterile samples are utilised to investigate any losses due to abiotic processes. The data from sterile samples are also used to interpret results and findings of non-sterile samples, especially in the context of sorption and non-extractable residue (NER) formation. However, to ensure the comparability of the data obtained from sterile and non-sterile experiments, effects of sterilisation on the soil matrix should be minimal. The objective of this study was to investigate the efficiencies of different sterilisation techniques and the impact of the sterilisation on sorption and NER formation in soil. In this study, experiments in accordance with OECD 307 and OECD 106 guidelines were performed with two soils covering wide range of soil characteristics and treated with the three sterilisation techniques autoclaving, gamma(γ)-radiation and adding 1% (w/w) sodium azide. As a test item, 14C-labelled phenanthrene and bromoxynil was used for OECD 307 test, whereas non-labelled phenanthrene and atrazine was used for OECD 106. The sterilisation efficiencies were investigated using traditional viable plate count and molecular approaches (RNA extraction method). The results suggest that none of the tested techniques resulted in completely sterilised soil with autoclaving being the most efficient technique. Adding sodium azide led to most inefficient sterilisation and a significant increase (0.56 units) in soil pH. OECD 307 results showed differences in NER formation of the test chemicals, especially for soil poisoning and γ-radiation, which could be due to inefficient sterilisation and/or change in soil physico-chemical properties. OECD 106 results suggest that none of the sterilisation techniques considerably affected sorption behaviour of the test chemicals. Based on our results, we recommend autoclaving as most suitable sterilisation technique.


Asunto(s)
Biodegradación Ambiental , Contaminantes del Suelo , Suelo , Esterilización , Contaminantes del Suelo/química , Contaminantes del Suelo/análisis , Esterilización/métodos , Suelo/química , Adsorción , Rayos gamma , Fenantrenos/química
7.
Appl Environ Microbiol ; 90(5): e0153823, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38587394

RESUMEN

A plethora of gene regulatory mechanisms with eccentric attributes in Deinoccocus radiodurans confer it to possess a distinctive ability to survive under ionizing radiation. Among the many regulatory processes, small RNA (sRNA)-mediated regulation of gene expression is prevalent in bacteria but barely investigated in D. radiodurans. In the current study, we identified a novel sRNA, DrsS, through RNA-seq analysis in D. radiodurans cells while exposed to ionizing radiation. Initial sequence analysis for promoter identification revealed that drsS is potentially co-transcribed with sodA and dr_1280 from a single operon. Elimination of the drsS allele in D. radiodurans chromosome resulted in an impaired growth phenotype under γ-radiation. DrsS has also been found to be upregulated under oxidative and genotoxic stresses. Deletion of the drsS gene resulted in the depletion of intracellular concentration of both Mn2+ and Fe2+ by ~70% and 40%, respectively, with a concomitant increase in carbonylation of intracellular protein. Complementation of drsS gene in ΔdrsS cells helped revert its intracellular Mn2+ and Fe2+ concentration and alleviated carbonylation of intracellular proteins. Cells with deleted drsS gene exhibited higher sensitivity to oxidative stress than wild-type cells. Extrachromosomally expressed drsS in ΔdrsS cells retrieved its oxidative stress resistance properties by catalase-mediated detoxification of reactive oxygen species (ROS). In vitro binding assays indicated that DsrS directly interacts with the coding region of the katA transcript, thus possibly protecting it from cellular endonucleases in vivo. This study identified a novel small RNA DrsS and investigated its function under oxidative stress in D. radiodurans. IMPORTANCE: Deinococcus radiodurans possesses an idiosyncratic quality to survive under extreme ionizing radiation and, thus, has evolved with diverse mechanisms which promote the mending of intracellular damages caused by ionizing radiation. As sRNAs play a pivotal role in modulating gene expression to adapt to altered conditions and have been delineated to participate in almost all physiological processes, understanding the regulatory mechanism of sRNAs will unearth many pathways that lead to radioresistance in D. radiodurans. In that direction, DrsS has been identified to be a γ-radiation-induced sRNA, which is also induced by oxidative and genotoxic stresses. DrsS appeared to activate catalase under oxidative stress and detoxify intracellular ROS. This sRNA has also been shown to balance intracellular Mn(II) and Fe concentrations protecting intracellular proteins from carbonylation. This novel mechanism of DrsS identified in D. radiodurans adds substantially to our knowledge of how this bacterium exploits sRNA for its survival under stresses.


Asunto(s)
Proteínas Bacterianas , Deinococcus , Regulación Bacteriana de la Expresión Génica , ARN Bacteriano , Especies Reactivas de Oxígeno , Deinococcus/genética , Deinococcus/efectos de la radiación , Deinococcus/metabolismo , Especies Reactivas de Oxígeno/metabolismo , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Radiación Ionizante , ARN Pequeño no Traducido/genética , ARN Pequeño no Traducido/metabolismo , Estrés Oxidativo , Rayos gamma
8.
Phys Med Biol ; 69(11)2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38657638

RESUMEN

Objective. Prompt gamma timing (PGT) uses the detection time of prompt gammas emitted along the range of protons in proton radiotherapy to verify the position of the Bragg peak (BP). Cherenkov detectors offer the possibility of enhanced signal-to-noise ratio (SNR) due to the inherent physics of Cherenkov emission which enhances detection of high energy prompt gamma rays relative to other induced uncorrelated signals. In this work, the PGT technique was applied to 3 semiconductor material slabs that emit only Cherenkov light for use in a full scale system: a 3 × 3 × 20 mm3TlBr, a 12 × 12 × 12 mm3TlBr, and a 5 × 5 × 5 mm3TlCl.Approach. A polymethyl methacrylate (PMMA) target was exposed to a 67.5 MeV, 0.5 nA proton beam and shifted in 3 mm increments at the Crocker nuclear laboratory (CNL) in Davis, CA, USA. A fast plastic scintillator coupled to a photomultiplier tube (PMT) provided the start reference for the proton time of flight. Time of flight (TOF) distributions were generated using this reference and the gamma-ray timestamp in the Cherenkov detector.Main results. The SNR of the proton correlated peaks relative to the background was 20, 29, and 30 for each of the three samples, respectively. The upper limit of the position resolutions with the TlCl sample were 2 mm, 3 mm, and 5 mm for 30k, 10k, and 5k detected events, respectively. The time distribution of events with respect to the reference reproduced with clarity the periodicity of the beam, implying a very high SNR of the Cherenkov crystals to detect prompt gammas. Background presence from the neutron-induced continuum, prompt gammas from deuterium, or positron activation were not observed. Material choice and crystal dimensions did not seem to affect significantly the outcome of the results.Significance. These results show the high SNR of the pure Cherenkov emitters TlBr and TlCl for the detection of prompt gammas in a proton beam with current of clinical significance and their potential for verifying the proton range. The accuracy in determining shifts of the BP was highly dependent on the number of events acquired, therefore, the performance of these detectors are expected to vary with different beam conditions such as current, pulse repetition, and proton bunch width.


Asunto(s)
Rayos gamma , Terapia de Protones , Factores de Tiempo , Terapia de Protones/instrumentación , Talio , Lutecio/química , Protones , Polimetil Metacrilato/química
9.
Methods Mol Biol ; 2788: 243-255, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38656518

RESUMEN

Gamma radiation (60Co)-induced mutagenesis offers an alternative to develop rice lines by accelerating the spontaneous mutation process and increasing the pool of allelic variants available for breeding. Ionizing radiation works by direct or indirect damage to DNA and subsequent mutations. The technique can take advantage of in vitro protocols to optimize resources and accelerate the development of traits. This is achieved by exposing mutants to a selection agent of interest in controlled conditions and evaluating large numbers of plants in reduced areas. This chapter describes the protocol for establishing gamma radiation dosimetry and in vitro protocols for optimization at the laboratory level using seeds as the starting material, followed by embryogenic cell cultures, somatic embryogenesis, and regeneration. The final product of the protocol is a genetically homogeneous population of Oryza sativa that can be evaluated for breeding against abiotic and biotic stresses.


Asunto(s)
Rayos gamma , Mutagénesis , Oryza , Semillas , Oryza/genética , Oryza/efectos de la radiación , Oryza/crecimiento & desarrollo , Mutagénesis/efectos de la radiación , Semillas/genética , Semillas/efectos de la radiación , Semillas/crecimiento & desarrollo , Regeneración/genética , Técnicas de Embriogénesis Somática de Plantas/métodos
10.
Microb Ecol ; 87(1): 58, 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602532

RESUMEN

Fungi play vital regulatory roles in terrestrial ecosystems. Local community assembly mechanisms, including deterministic and stochastic processes, as well as the size of regional species pools (gamma diversity), typically influence overall soil microbial community beta diversity patterns. However, there is limited evidence supporting their direct and indirect effects on beta diversity of different soil fungal functional groups in forest ecosystems. To address this gap, we collected 1606 soil samples from a 25-ha subtropical forest plot in southern China. Our goal was to determine the direct effects and indirect effects of regional species pools on the beta diversity of soil fungi, specifically arbuscular mycorrhizal (AM), ectomycorrhizal (EcM), plant-pathogenic, and saprotrophic fungi. We quantified the effects of soil properties, mycorrhizal tree abundances, and topographical factors on soil fungal diversity. The beta diversity of plant-pathogenic fungi was predominantly influenced by the size of the species pool. In contrast, the beta diversity of EcM fungi was primarily driven indirectly through community assembly processes. Neither of them had significant effects on the beta diversity of AM and saprotrophic fungi. Our results highlight that the direct and indirect effects of species pools on the beta diversity of soil functional groups of fungi can significantly differ even within a relatively small area. They also demonstrate the independent and combined effects of various factors in regulating the diversities of soil functional groups of fungi. Consequently, it is crucial to study the fungal community not only as a whole but also by considering different functional groups within the community.


Asunto(s)
Microbiota , Micorrizas , China , Bosques , Rayos gamma , Suelo
11.
Curr Biol ; 34(9): 1819-1830.e6, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38614079

RESUMEN

Tardigrades can survive remarkable doses of ionizing radiation, up to about 1,000 times the lethal dose for humans. How they do so is incompletely understood. We found that the tardigrade Hypsibius exemplaris suffers DNA damage upon gamma irradiation, but the damage is repaired. We show that this species has a specific and robust response to ionizing radiation: irradiation induces a rapid upregulation of many DNA repair genes. This upregulation is unexpectedly extreme-making some DNA repair transcripts among the most abundant transcripts in the animal. By expressing tardigrade genes in bacteria, we validate that increased expression of some repair genes can suffice to increase radiation tolerance. We show that at least one such gene is important in vivo for tardigrade radiation tolerance. We hypothesize that the tardigrades' ability to sense ionizing radiation and massively upregulate specific DNA repair pathway genes may represent an evolved solution for maintaining DNA integrity.


Asunto(s)
Reparación del ADN , Rayos gamma , Radiación Ionizante , Tardigrada , Regulación hacia Arriba , Animales , Reparación del ADN/genética , Tardigrada/genética , Daño del ADN , Tolerancia a Radiación/genética
12.
Carbohydr Polym ; 336: 122121, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38670753

RESUMEN

This study aimed to modify chitosan (CS) by gamma irradiation and use it as a surface coating of nanoparticles (NPs) fabricated of poly lactic-co-glycolic acid (PLGA) to create mostly biocompatible nanosystems that can transport drugs to neurons. Gamma irradiation produced irradiated CS (CSγ) with a very low molecular weight (15.2-19.2 kDa). Coating NPs-PLGA with CSγ caused significant changes in their Z potential, making it slightly positive (from -21.7 ± 2.8 mV to +7.1 ± 2.3 mV) and in their particle size (184.4 0.4 ± 7.9 nm to 211.9 ± 14.04 nm). However, these changes were more pronounced in NPs coated with non-irradiated CS (Z potential = +54.0 ± 1.43 mV, size = 348.1 ± 16.44 nm). NPs coated with CSγ presented lower cytotoxicity and similar internalization levels in SH-SY5Y neuronal cells than NPs coated with non-irradiated CS, suggesting higher biocompatibility. Highly biocompatible NPs are desirable as nanocarriers to deliver drugs to the brain, as they help maintain the structure and function of the blood-brain barrier. Therefore, the NPs developed in this study could be evaluated as drug-delivery systems for treating brain diseases.


Asunto(s)
Quitosano , Nanopartículas , Neuronas , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Quitosano/química , Humanos , Nanopartículas/química , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Copolímero de Ácido Poliláctico-Ácido Poliglicólico/química , Portadores de Fármacos/química , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Tamaño de la Partícula , Rayos gamma
13.
J Cancer Res Ther ; 20(1): 261-267, 2024 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-38554331

RESUMEN

BACKGROUND AND OBJECTIVE: Radiation therapy is a routine clinical practice that has been used for a long time in the treatment of cancer patients. The most important dose-limiting organ in patients receiving radiotherapy for various conditions is the brain. The mechanisms underlying brain and pituitary gland damage caused by radiation are largely unknown. It is of great importance to use radioprotective agents to protect against damage. This study aims to evaluate the neuroprotective effects of quercetin in experimental radiation-induced brain and pituitary gland damage. MATERIALS AND METHODS: A total of 60 adult male Wistar-albino rats were randomly divided into six groups (control, sham, radiation, quercetin, radiation + quercetin, and quercetin + radiation groups, with ten rats in each group). Quercetin was given to rats by oral gavage at 50 mg/kg/day. A whole-body single dose of 10 Gy radiation was applied to the rats. Tissue samples belonging to the groups were compared after excision. Histopathological changes in the brain tissue and pituitary gland were examined with hematoxylin-tissue samples in the groups and compared histologically and immunohistochemically. RESULTS: The histopathological examination of the brain and anterior pituitary gland sections showed marked damage in the radiation-treated rats, while the quercetin-administered groups showed normal tissue architecture. While neuropeptid Y immunoreactivity was increased, synaptophysin immunoreactivity was decreased in the brains of radiation-treated rats. However, when neuropeptide Y and synaptophysin expression were assessed in the anterior pituitary gland, there was no significant difference between the groups. CONCLUSION: Consequently, quercetin may be a potential pharmacological agent in modulating radiation-induced damage in rats. However, extra experimental and preclinical studies are needed to confirm our findings before they can be used clinically.


Asunto(s)
Fármacos Neuroprotectores , Quercetina , Humanos , Ratas , Masculino , Animales , Quercetina/farmacología , Quercetina/uso terapéutico , Rayos gamma/efectos adversos , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéutico , Sinaptofisina , Ratas Wistar , Estrés Oxidativo , Antioxidantes/farmacología
14.
Appl Radiat Isot ; 208: 111286, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38498957

RESUMEN

Dried figs were studied by Electron Paramagnetic Resonance (EPR) spectroscopy for identification of radiation treatment and dosage assessment. Gamma-irradiated samples show a multicomponent "sugar-like" EPR spectrum with line width of 6-8 mT, centered at g = 2.004. The investigation of the influence of the instrumental parameters microwave power and modulation amplitude on the EPR signal show saturation effect at microwave power above 2 mW and over modulation at modulation amplitude above 0.4 mT. Determination of the stability of radiation induced signals shows, that identification of previous radiation treatment is possible for a long time period after irradiation even more than one year. Dose-response curves of gamma-irradiated samples exhibits a linear response up to about 4 kGy and the saturation of the EPR signal at higher doses. A Single Aliquot Additive dosing method used to estimate the initial absorbed dose in irradiated dried fig flesh shows initial dose 0.25 kGy for the sample irradiated by 5 kGy and 3.7 kGy for those irradiated using 10 kGy. Taking into account the signal decay after 150 days of storage, the dose defined as initial should be 4.65 kGy for the 5 kGy irradiated sample and 8 kGy for that irradiated using 10 kGy.


Asunto(s)
Ficus , Espectroscopía de Resonancia por Spin del Electrón/métodos , Rayos gamma
15.
Radiat Prot Dosimetry ; 200(6): 544-553, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38446413

RESUMEN

Our work investigated the radioprotection implications associated with the possession of a collection of uraniferous minerals. Considering different scenarios, we developed (and applied to an actual collection) specific formulas for radiation doses evaluation. We discussed the shielding necessary to reduce the gamma irradiation down to the required values. A mathematical model was developed to estimate the minimum air flow rate to reduce the radon air concentration below the reference values. The radiation risks associated to the handling of single specimens was also addressed, including hand skin irradiation and shielding capabilities of surgical lead gloves. Finally, we discussed the radiation risks associated to the exhibition of a single specimen. The results, compared to the safety standards of the EU Directive 13/59, show that the exhibition of uraniferous samples with activity of a few MBq do not need specific radioprotection requirements nor for the involved personnel nor for visitors.


Asunto(s)
Exposición Profesional , Monitoreo de Radiación , Protección Radiológica , Protección Radiológica/normas , Protección Radiológica/métodos , Humanos , Exposición Profesional/análisis , Exposición Profesional/prevención & control , Monitoreo de Radiación/métodos , Dosis de Radiación , Minerales/análisis , Rayos gamma , Radón/análisis , Contaminantes Radiactivos del Aire/análisis , Uranio/análisis , Modelos Teóricos
16.
Radiat Prot Dosimetry ; 200(6): 572-579, 2024 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-38465479

RESUMEN

In the calibration procedure of area gamma dosemeters, how to accurately evaluate and correct the scattering contribution from the complex environmental factors to the point of test is the key problem to ensure the calibration accuracy. This paper proposed a fast correction method of the scattering contributions in the area gamma dosemeter calibration field. First, Monte Carlo method is employed to simulate the influence of scattering caused by different environmental factors in the calibration field, which is named as semi-panoramic reference radiation field. Then, a prediction model of the relationship between environmental factors and environmental scattering contribution is constructed based on the simulation data through the least squares support vector machine. With the model, the scattering contribution from the environmental factors can be fast estimated to correct the calibration results of the area gamma dosemeters, which will improve the accuracy of the calibration.


Asunto(s)
Rayos gamma , Método de Montecarlo , Dispersión de Radiación , Calibración , Monitoreo de Radiación/métodos , Monitoreo de Radiación/instrumentación , Monitoreo de Radiación/normas , Humanos , Dosímetros de Radiación/normas , Algoritmos , Máquina de Vectores de Soporte , Dosis de Radiación , Simulación por Computador
17.
Int J Radiat Biol ; 100(5): 678-688, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38451191

RESUMEN

PURPOSE: To provide an updated summary of recent advances in the application of gamma irradiation to elicit secondary metabolism and for induction of mutations in plant cell and organ cultures for the production of industrially important specialized metabolites (SMs). CONCLUSIONS: Research on the application of gamma radiation with plants has contributed a lot to microbial decontamination of seeds, and the promotion of physiological processes such as seed germination, seedling vigor, plant growth, and development. Various studies have demonstrated the influence of gamma rays on the morphology, physiology, and biochemistry of plants. Recent research efforts have also shown that low-dose gamma (5-100 Gy) irradiation can be utilized as an expedient solution to alleviate the deleterious effect of abiotic stresses and to obtain better yields of plants. Inducing mutagenesis using gamma irradiation has also evolved as a better option for inducing genetic variability in crops, vegetables, medicinal and ornamentals for their genetic improvement. Plant SMs are gaining increasing importance as pharmaceutical, therapeutic, cosmetic, and agricultural products. Plant cell, tissue, and organ cultures represent an attractive alternative to conventional methods of procuring useful SMs. Among the varied approaches the elicitor-induced in vitro culture techniques are considered an efficient tool for studying and improving the production of SMs. This review focuses on the utilization of low-dose gamma irradiation in the production of high-value SMs such as phenolics, terpenoids, and alkaloids. Furthermore, we present varied successful examples of gamma-ray-induced mutations in the production of SMs.


Asunto(s)
Rayos gamma , Células Vegetales , Metabolismo Secundario , Metabolismo Secundario/efectos de la radiación , Células Vegetales/metabolismo , Células Vegetales/efectos de la radiación
18.
Int J Biol Macromol ; 266(Pt 1): 131038, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38518931

RESUMEN

Aqueous solutions of alginate (4 %) with or without hydrogen peroxide (0-2 % H2O2) were irradiated under a gamma Co-60 source. The effect of dose rate on the radiation scission yield (Gs) of resulting irradiated alginate was determined. At the dose of 20 kGy, the G(s) value of irradiated alginate decreased with the increase dose rate, suggesting that the irradiation at a suitable dose rate could further improve the radiation chemical yield of degradation. For the alginate irradiated at the same dose rate, G(s) value increased with the increase of H2O2 concentration. Average molecular weight (Mw) and polydispersity index (PI) of irradiated alginate rapidly decreased with the increase in dose and further decreased by addition of H2O2. The oligoalginate with Mw ~ 9800 g/mol was obtained by radiation degradation of 4 % alginate solution containing 2 % H2O2 at dose of 20 kGy. Radiation scission of glycoside bonds and formation of carbonyl groups (C=O) were indicated in UV and FTIR spectra of irradiated alginate. Peanut seedlings were fertilized with alginate and oligoalginate solutions, and the results showed that all growth parameters of the treated plants were better than those of the control. Furthermore, the oligoalginate prepared by gamma irradiation can be applied as a plant growth promoter for agriculture production.


Asunto(s)
Alginatos , Arachis , Rayos gamma , Peróxido de Hidrógeno , Peso Molecular , Alginatos/química , Arachis/química , Arachis/efectos de la radiación , Peróxido de Hidrógeno/química , Relación Dosis-Respuesta en la Radiación
19.
Int J Mol Sci ; 25(5)2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38474235

RESUMEN

Combined radiation with hemorrhage (combined injury, CI) exacerbates hematopoietic acute radiation syndrome and mortality compared to radiation alone (RI). We evaluated the effects of RI or CI on blood cell depletion as a biomarker to differentiate the two. Male CD2F1 mice were exposed to 8.75 Gy γ-radiation (60Co). Within 2 h of RI, animals were bled under anesthesia 0% (RI) or 20% (CI) of total blood volume. Blood samples were collected at 4-5 h and days 1, 2, 3, 7, and 15 after RI. CI decreased WBC at 4-5 h and continued to decrease it until day 3; counts then stayed at the nadir up to day 15. CI decreased neutrophils, lymphocytes, monocytes, eosinophils, and basophils more than RI on day 1 or day 2. CI decreased RBCs, hemoglobin, and hematocrit on days 7 and 15 more than RI, whereas hemorrhage alone returned to the baseline on days 7 and 15. RBCs depleted after CI faster than post-RI. Hemorrhage alone increased platelet counts on days 2, 3, and 7, which returned to the baseline on day 15. Our data suggest that WBC depletion may be a potential biomarker within 2 days post-RI and post-CI and RBC depletion after 3 days post-RI and post-CI. For hemorrhage alone, neutrophil counts at 4-5 h and platelets for day 2 through day 7 can be used as a tool for confirmation.


Asunto(s)
Eritrocitos , Hemorragia , Masculino , Animales , Ratones , Rayos gamma , Monocitos , Biomarcadores
20.
Appl Radiat Isot ; 207: 111249, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38428203

RESUMEN

The 71Ga(n,γ)72Ga reaction-based epithermal neutron flux detectors are novel instruments developed to measure the epithermal neutron flux of boron neutron capture therapy (BNCT) treatment beams. In this study, a spherical epithermal neutron flux detector using 71Ga(n,γ)72Ga reaction was prototyped. The performance of the detector was experimentally evaluated at an accelerator-based BNCT (AB-BNCT) device developed by Lanzhou University, China. Based on the experimental results and related analysis, we demonstrated that the detector is a reliable tool for the quality assurance of BNCT treatment beams.


Asunto(s)
Terapia por Captura de Neutrón de Boro , Humanos , Terapia por Captura de Neutrón de Boro/métodos , Neutrones , Dosificación Radioterapéutica , Rayos gamma , Método de Montecarlo
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