RESUMO
Thunderstorms emit fluxes of gamma rays known as gamma-ray glows1,2, sporadically observed by aircraft1,3-7, balloons8-11 and from the ground12-18. Observations report increased gamma-ray emissions by tens of percent up to two orders of magnitude above the background, sometimes abruptly terminated by lightning discharges1,3-5. Glows are produced by the acceleration of energetic electrons in high-electric-field regions within thunderclouds8 and contribute to charge dissipation3. Glows had been considered as quasi-stationary phenomena3,5,12, with durations up to a few tens of seconds and spatial scales up to 10-20 km. However, no measurements of the full extension in space and time of a gamma-ray-glow region and their occurring frequency have been reported so far. Here we show that tropical thunderclouds over ocean and coastal regions commonly emit gamma rays for hours over areas up to a few thousand square kilometres. Emission is associated with deep convective cores; it is not uniform and continuous but shows characteristic timescales of 1-10 s and even subsecond for individual glows. The dynamics of gamma-glowing thunderclouds strongly contradicts the quasi-stationary picture of glows and instead resembles that of a huge gamma-glowing 'boiling pot' in both pattern and behaviour.
Assuntos
Raios gama , Clima Tropical , Fatores de Tempo , Oceanos e Mares , Vento , ElétronsRESUMO
Two different hard-radiation phenomena are known to originate from thunderclouds: terrestrial gamma-ray flashes (TGFs)1 and gamma-ray glows2. Both involve an avalanche of electrons accelerated to relativistic energies but are otherwise different. Glows are known to last for one to hundreds of seconds, have moderate intensities and originate from quasi-stationary thundercloud fields2-5. TGFs exhibit high intensities and have characteristic durations of tens to hundreds of microseconds6-9. TGFs often show a close association with an emission of strong radio signals10-17 and optical pulses18-21, which indicates the involvement of lightning leaders in their generation. Here we report unique observations of a different phenomenon, which we call flickering gamma-ray flashes (FGFs). FGFs resemble the usual multi-pulse TGFs22-24 but have more pulses and each pulse has a longer duration than ordinary TGFs. FGF durations span from 20 to 250 ms, which reaches the lower boundary of the gamma-ray glow duration. FGFs are radio and optically silent, which makes them distinct from normal TGFs. An FGF starts as an ordinary gamma-ray glow, then suddenly increases exponentially in intensity and turns into an unstable, 'flickering' mode with a sequence of pulses. FGFs could be the missing link between the gamma-ray glows and conventional TGFs, whose absence has been puzzling the atmospheric electricity community for two decades.
Assuntos
Raios gama , Fatores de Tempo , ElétronsRESUMO
Cucumber (Cucumis sativus L.) is a major vegetable crop grown globally, with a cultivation history of more than 3000 years. The limited genetic diversity, low rate of intraspecific variation, and extended periods of traditional breeding have resulted in slow progress in their genetic research and the development of new varieties. Gamma (γ)-ray irradiation potentially accelerates the breeding progress; however, the biological and molecular effects of γ-ray irradiation on cucumbers are unknown. Exposing cucumber seeds to 0, 50, 100, 150, 200, and 250 Gy doses of 60Co-γ-ray irradiation, this study aimed to investigate the resulting phenotype and physiological characteristics of seedling treatment to determine the optimal irradiation dose. The results showed that low irradiation doses (50-100 Gy) enhanced root growth, hypocotyl elongation, and lateral root numbers, promoting seedling growth. However, high irradiation doses (150-250 Gy) significantly inhibited seed germination and growth, decreasing the survival rate of seedlings. More than 100 Gy irradiation significantly decreased the total chlorophyll content while increasing the malondialdehyde (MDA) and H2O2 content in cucumber. Transcriptome sequencing analysis at 0, 50, 100, 150, 200, and 250 Gy doses showed that gene expression significantly differed between low and high irradiation doses. Gene Ontology enrichment and functional pathway enrichment analyses revealed that the auxin response pathway played a crucial role in seedling growth under low irradiation doses. Further, gene function analysis revealed that small auxin up-regulated gene CsSAUR37 was a key gene that was overexpressed in response to low irradiation doses, promoting primary root elongation and enhancing lateral root numbers by regulating the expression of protein phosphatase 2Cs (PP2Cs) and auxin synthesis genes.
Assuntos
Cucumis sativus , Raios gama , Regulação da Expressão Gênica de Plantas , Germinação , Proteínas de Plantas , Plântula , Plântula/efeitos da radiação , Plântula/crescimento & desenvolvimento , Plântula/genética , Cucumis sativus/efeitos da radiação , Cucumis sativus/genética , Cucumis sativus/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Germinação/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos da radiação , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Radioisótopos de Cobalto , Relação Dose-Resposta à Radiação , Ácidos Indolacéticos/metabolismo , Clorofila/metabolismo , Sementes/efeitos da radiação , Sementes/crescimento & desenvolvimento , Sementes/genética , Perfilação da Expressão GênicaRESUMO
OBJECTIVE: Our study aimed to establish a standardized methodology for selecting "reference" and "evaluated" distributions in gamma analysis for Monte Carlo (MC) based intensity modulated treatment plans. Evaluation of importance of reference selection in MC based and non MC based treatment planning systems were analysed using a study classification. METHODS: Three categories were utilized to analyzed gamma passing rates across using different treatment planning systems (TPS) and detectors for thirty five patients. Category 1 utilized MC-based Monaco TPS plans and a 2 dimensional(2D) I'mRTMatriXX detector. Category 2 employed non-MC-based Eclipse TPS plans, assessed with a 2D I'mRTMatriXX detector. In Category 3, MC-based Monaco TPS plans were validated using a Dolphin detector. All plans were subjected to analysis using gamma criteria, which considered a dose difference of 3% and a distance to agreement of 3mm. Additionally, another set of gamma criteria was employed, with a dose difference of 3% and a distance to agreement of 2mm. An introduced Asymmetric factors in both 2D and 3D analysis will quantify the asymmetric nature of gamma based on the choice of "reference" distribution. RESULT: For 2D Gamma analysis, MC-based Monaco TPS and I'mRTMatriXX showed a consistent positive Zk2D trend for all patients, with significant p-values below 0.01 for both gamma passing criteria. In contrast, non-MC based Eclipse TPS exhibited varied Zk2D results, with non-significant p-values. In 3D Gamma analysis, all patients exhibited positive Zk3D values with significant p-values below 0.01 when "references" were swapped. The Pearson correlation between asymmetricity and isodose volumes was notably high at 0.99 for both gamma criteria. CONCLUSION: Our study highlights the imperative of using MC-based TPS as the definitive "reference" in gamma analysis for patient specific quality assurance of intensity modulated radiation therapy, emphasizing that variations can mislead results, especially given gamma analysis's sensitivity to MC calculation noise.
Assuntos
Método de Monte Carlo , Garantia da Qualidade dos Cuidados de Saúde , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada , Humanos , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Raios gama/uso terapêutico , Neoplasias/radioterapiaRESUMO
In this study, the protective effects of Panax notoginseng saponins (PNS) against gamma radiation-induced DNA damage and associated physiological alterations in Swiss albino mice were investigated. Exposure to gamma radiation led to a dose-dependent increase in cytokinesis-blocked micronuclei (CBMN) double-strand DNA breaks (DSBs), dicentric aberrations (DC), formation in peripheral blood mononuclear cells. However, pretreatment with PNS at concentrations of 1, 5, and 10 µg/mL significantly attenuated the frequencies of DC and CBMN in a concentration-dependent manner. PNS administration before radiation exposure also reduced radiation-induced DSBs in BL, indicating protection against reactive oxygen species generation and DNA damage. Notably, pretreatment with PNS at 10 µg/mL prevented the overexpression of γ-H2AX, proteins associated with DNA damage response, in irradiated mice. In addition, in vivo studies showed intraperitoneal administration of PNS (25 mg/kg body weight) for 1 h before radiation exposure mitigated lipid peroxidation levels and restored antioxidant status, countering oxidative damage induced by gamma radiation. Furthermore, PNS pretreatment reversed the decrease in hemoglobin (Hb) content, white blood cell count, and red blood cell count in irradiated mice, indicating preservation of hematological parameters. Overall, PNS demonstrated an anticlastogenic effect by modulating radiation-induced DSBs and preventing oxidative damage, thus highlighting its potential as a protective agent against radiation-induced DNA damage and associated physiological alterations. Clinically, PNS will be beneficial for cancer patients undergoing radiotherapy, but their pharmacological properties and toxicity profiles need to be studied.
Assuntos
Raios gama , Panax notoginseng , Saponinas , Animais , Raios gama/efeitos adversos , Saponinas/farmacologia , Camundongos , Panax notoginseng/química , Humanos , Masculino , Dano ao DNA/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/efeitos da radiação , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Protetores contra Radiação/farmacologia , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Monócitos/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Antioxidantes/farmacologiaRESUMO
A recent scientific investigation has shown promising results of selenium nanoparticles (SeNPs) for the anticancer and antimicrobial activities. This study aims to evaluate the effects of PVP SeNPs on bacterial strains, including Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus), Klebsiella pneumoniae (K. pneumoniae), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa). Also, its antitumor activity against the MRC-5 carcinoma cell line. SeNPs were prepared via gamma irradiation using PVP as a capping agent, and their size and morphological structure were determined using HRTEM. The size of the SeNPs ranged from 36 to 66.59 nm. UV-vis spectra confirmed the formation of SeNPs, while FTIR measurement confirmed a change in the PVP structure after adding selenium nanoparticles. The highest effect was reported on HepG2 by an IC50 with a value of 8.87 µg/ml, followed by HeLa, PC3, MCF-7, and Caco2 cell lines, respectively. Furthermore, ZOI reached 36.33 ± 3.05 mm. The best value of the minimum inhibitory concentration (MIC) was 0.313 µg/ml. Scanning electron microscope (SEM) imaging against bacteria showed deformations and distortions in their structures. Transmission electron (TEM) revealed ultrastructure changes in treated bacteria because of the free radicals that made cytotoxicity which confirmed by Electron spin resonance (ESR).
Assuntos
Antibacterianos , Raios gama , Testes de Sensibilidade Microbiana , Selênio , Humanos , Antibacterianos/farmacologia , Antibacterianos/química , Selênio/química , Selênio/farmacologia , Antineoplásicos/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Bactérias/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Bacillus cereus/efeitos dos fármacos , Nanopartículas/química , Pseudomonas aeruginosa/efeitos dos fármacosRESUMO
To evaluate the effect of irradiation on the preservation of potatoes, fresh potatoes were selected as the irradiation objects, and irradiated with 60Co-γ radiation source for 0, 100, 200, 500 and 1000 Gy, respectively. During the irradiation, the well-packaged Y1.79Bi0.01Eu0.2MgTiO6 novel thermoluminescence dosimeter material was placed together with the potatoes at the same position. Then, the potatoes were stored in the same temperature and humidity environment, and the quality changes of the potatoes were observed. The Y1.79Bi0.01Eu0.2MgTiO6 material had good performance indicators, and was used to measure the irradiation dose of the potatoes. The experiment showed that irradiation could appropriately extend the storage time of potatoes, and gamma irradiation of about 1000 Gy could achieve the best preservation effect. The main pathogenic fungi that cause dry rot of potatoes were Fusarium solani and Fusarium oxysporum, and the appropriate dose of 60Co-γ irradiation could effectively inhibit the spread and growth of these fungi.
Assuntos
Radioisótopos de Cobalto , Irradiação de Alimentos , Raios gama , Solanum tuberosum , Solanum tuberosum/microbiologia , Solanum tuberosum/efeitos da radiação , Irradiação de Alimentos/métodos , Fusarium/efeitos da radiação , Conservação de Alimentos/métodosRESUMO
One of the major demands in gamma spectrometry of environmental samples is the accurate determination of activity concentration of present radionuclides (naturally occurring and those of artificial origin), due to the fact they are commonly of relatively low content. Thus, all these measurements have in common that the detection limit, in the spectral region of interest should be as low as possible. For this reason, the construction of a good passive, as well as active shield requires a detailed knowledge of the origin of the background events in the absence of an environmental sample. In addition, an analysis of the impact on detection limits due to the presence of the sample itself is also important. Also, the knowledge of the statistical basics for low-level counting is helpful to enable the best choice of detector characteristics (relative efficiency, peak to Compton ratio, resolution), measuring time, and required level of precaution against the different background contributions. In this paper, the background spectra of several gamma spectroscopy systems (with passive and active veto shields) are analyzed and discussed, regarding their capabilities for measurements of environmental samples. Furthermore, various environmental samples are analyzed by low-level gamma spectrometry, including the sample measurements in the presence of an active veto shield against cosmic-ray muons. The disturbance of radioactive equilibrium between members of radioactive series in the samples is commented on, together with the possibility of use of certain gamma lines (including their interference and the corresponding intensities) for radionuclide activities determination.
Assuntos
Raios gama , Monitoramento de Radiação , Espectrometria gama , Monitoramento de Radiação/métodos , Espectrometria gama/métodosRESUMO
The salivary glands are often damaged during head and neck cancer radiotherapy. This results in chronic dry mouth, which adversely affects quality of life and for which there is no long-term cure. Mouse models of salivary gland injury are routinely used in regenerative research. However, there is no clear consensus on the radiation regime required to cause injury. Here, we analysed three regimes of γ-irradiation of the submandibular salivary gland. Transcriptional analysis, immunofluorescence and flow cytometry was used to profile DNA damage, gland architecture and immune cell changes 3â days after single doses of 10 or 15â Gy or three doses of 5â Gy. Irrespective of the regime, radiation induced comparable levels of DNA damage, cell cycle arrest, loss of glandular architecture, increased pro-inflammatory cytokines and a reduction in tissue-resident macrophages, relative to those observed in non-irradiated submandibular glands. Given these data, coupled with the fact that repeated anaesthetic can negatively affect animal welfare and interfere with saliva secretion, we conclude that a single dose of 10â Gy irradiation is the most refined method of inducing acute salivary gland injury in a mouse model.
Assuntos
Dano ao DNA , Fracionamento da Dose de Radiação , Camundongos Endogâmicos C57BL , Glândulas Salivares , Animais , Glândulas Salivares/efeitos da radiação , Glândulas Salivares/patologia , Glândula Submandibular/efeitos da radiação , Glândula Submandibular/patologia , Raios gama/efeitos adversos , Citocinas/metabolismo , Camundongos , Masculino , Macrófagos/efeitos da radiação , Macrófagos/patologia , Macrófagos/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Relação Dose-Resposta à Radiação , FemininoRESUMO
A model for accelerated aging in mice was developed: CB6F2 mice aged 39-45 days were exposed to fractionated 4-fold relatively uniform γ-radiation (137Cs, 0.98 Gy/min) at a total dose of 6.8 Gy. Radiation exposure led to delayed active growth, leukopenia, and lymphopenia for over 1 year during the post-radiation period. The death of irradiated males and females occurred significantly earlier than in control group animals. Median lifespans in the experimental group were 35-38% lower than in the control group (p<0.001). Ionizing radiation exposure led to the early development of hair depigmentation, cachexia, and the development of aging-associated diseases. In irradiated mice, oncological pathology constituted 30-35% in the mortality structure, which is twice as often as in the control group. The developed model can be used to study the pathogenesis of accelerated aging under radiation exposure and the search for means of its prevention and treatment.
Assuntos
Senilidade Prematura , Raios gama , Animais , Camundongos , Masculino , Feminino , Raios gama/efeitos adversos , Senilidade Prematura/patologia , Senilidade Prematura/genética , Senilidade Prematura/etiologia , Longevidade/efeitos da radiação , Radiação Ionizante , Envelhecimento/efeitos da radiação , Caquexia/patologia , Caquexia/etiologia , Radioisótopos de CésioRESUMO
This study investigates the radon concentration in groundwater in Kupwara, the northernmost district of the Kashmir valley. It further assesses the annual effective dose experienced by the district's diverse population-infants, children, and adults-attributable to both inhalation of airborne radon released from drinking water and direct ingestion. In addition to this, the calculation of gamma dose rate is also carried out at each of the sampling site of radon. A portable radon-thoron monitor and a portable gamma radiation detector were respectively employed to estimate the activity concentration of radon in water samples and to measure the gamma dose rate. The radon concentration was found to exhibit variability from a minimum of 2.9 BqL-1 to a maximum of 197.2 BqL-1, with a mean of 26.3 BqL-1 and a standard deviation of 23.3 BqL-1. From a total of 85 samples, 10.6% of the samples had radon activity concentrations exceeding the permissible limits of 40 BqL-1 set by the United Nations Scientific Committee on Effects of Atomic Radiations as reported by UNSCEAR (Sources and effects of ionizing radiation, 2008) and only 1.2% of the samples have radon activity concentration exceeding the permissible limits of 100 BqL-1 set by the World Health Organization as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The mean of the annual effective dose due to inhalation for all age groups as well as the annual ingestion dose for infants and children, surpasses the World Health Organization's limit of 100 µSv y-1 as reported by WHO (WHO guidelines for drinking-water quality, World Health Organization, Geneva, 2008). The observed gamma radiation dose rate in the vicinity of groundwater radon sites ranged from a minimum of 138 nSv h-1 to a maximum of 250 nSv h-1. The data indicated no significant correlation between the dose rate of gamma radiation and the radon levels in the groundwater. Radon concentration of potable water in the study area presents a non-negligible exposure pathway for residents. Therefore, the judicious application of established radon mitigation techniques is pivotal to minimize public health vulnerabilities.
Assuntos
Água Subterrânea , Monitoramento de Radiação , Radônio , Poluentes Radioativos da Água , Radônio/análise , Água Subterrânea/química , Índia , Poluentes Radioativos da Água/análise , Humanos , Água Potável/química , Água Potável/análise , Lactente , Criança , Doses de Radiação , Raios gama , Exposição à Radiação/análise , AdultoRESUMO
Understanding the hazards of space radiation is imperative as astronauts begin voyaging on missions with increasing distances from Earth's protective shield. Previous studies investigating the acute or long-term effects of specific ions comprising space radiation have revealed threats to organs generally considered radioresistant, like the brain, and have shown males to be more vulnerable than their female counterparts. However, astronauts will be exposed to a combination of ions that may result in additive effects differing from those of any one particle species. To better understand this nuance, we irradiated 4-month-old male and female, wild-type and Alzheimer's-like mice with 0, 0.5, or 0.75 Gy galactic cosmic ray simulation (GCRsim) or 0, 0.75, or 2 Gy gamma radiation (wild-type only). At 11 months, mice underwent brain and heart MRIs or behavioral tests, after which they were euthanized to assess amyloid-beta pathology, heart and kidney gene expression and fibrosis, and plasma cytokines. Although there were no changes in amyloid-beta pathology, we observed many differences in brain MRIs and behavior, including opposite effects of GCRsim on motor coordination in male and female transgenic mice. Additionally, several genes demonstrated persistent changes in the heart and kidney. Overall, we found sex- and genotype-specific, long-term effects of GCRsim and gamma radiation on the brain, heart, and kidney.
Assuntos
Doença de Alzheimer , Encéfalo , Radiação Cósmica , Raios gama , Coração , Rim , Camundongos Transgênicos , Animais , Doença de Alzheimer/genética , Doença de Alzheimer/etiologia , Doença de Alzheimer/patologia , Feminino , Masculino , Raios gama/efeitos adversos , Encéfalo/efeitos da radiação , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/diagnóstico por imagem , Camundongos , Rim/efeitos da radiação , Rim/metabolismo , Rim/patologia , Coração/efeitos da radiação , Radiação Cósmica/efeitos adversos , Mutação , Caracteres Sexuais , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/genética , Modelos Animais de Doenças , Fatores SexuaisRESUMO
The main focus of this study was on using radiation to make an ultra-absorbent hydrogel (UAH) from sodium alginate (SA) and gelatin (GL) biopolymers. This UAH can effectively handle water and nitrogen in wheat farming during drought stress. The hydrogel was synthesized by gamma irradiation-induced SA/GL/polyacrylamide crosslinking at 10-40 kGy. Varying SA/GL ratios affected swelling and the gel fraction of SA/GL/PAm hydrogels. The (SA/GL 17/83) hydrogel exhibited a 40.03 g/g swelling degree, while increasing SA content resulted in higher swelling, peaking at 75.5 g/g for (SA/GL 83/17). This indicated a synergistic interaction between SA and GL. The gel fraction also increased from 76.8 to 90.3%, with a higher GL content reflecting increased crosslinking. After multiple hydrolysis cycles, the hydrogel achieved 1293 (g/g) swelling and 36 days of water retention. When applied to wheat (Triticuma estivum) under drought stress, it significantly improved shoot length (18%), root length (43%), shoot fresh weight (49%), and shoot dry weight (51%) under extreme drought. The significant increases in protein and carbohydrate content in both shoots (up to 32% and 19%, respectively) and grains (up to 21% and 24%, respectively), along with the reduction in proline content (up to 38%), demonstrate that ultra-absorbent hydrogel (UAH) effectively enhances nitrogen content, photosynthesis, and overall plant health in wheat under varying drought stress levels. This novel SA/GL-based UAH holds promise for addressing water scarcity and agricultural challenges, offering a sustainable solution for water and nitrogen management under drought stress.
Assuntos
Alginatos , Secas , Gelatina , Hidrogéis , Nitrogênio , Triticum , Água , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Triticum/fisiologia , Alginatos/química , Gelatina/química , Nitrogênio/metabolismo , Nitrogênio/química , Hidrogéis/química , Água/química , Estresse Fisiológico , Raios gamaRESUMO
This study investigates the efficacy of Trichoderma spp. and Bacillus spp., as well as their gamma radiation-induced mutants, as potential biological control agents against Meloidogyne javanica (Mj) in tomato plants. The research encompasses in vitro assays, greenhouse trials, and molecular identification methodologies to comprehensively evaluate the biocontrol potential of these agents. In vitro assessments reveal significant nematicidal activity, with Bacillus spp. demonstrating notable effectiveness in inhibiting nematode egg hatching (16-45%) and inducing second-stage juvenile (J2) mortality (30-46%). Greenhouse trials further confirm the efficacy of mutant isolates, particularly when combined with chitosan, in reducing nematode-induced damage to tomato plants. The combination of mutant isolates with chitosan reduces the reproduction factor (RF) of root-knot nematodes by 94%. By optimizing soil infection conditions with nematodes and modifying the application of the effective compound, the RF of nematodes decreases by 65-76%. Molecular identification identifies B. velezensis and T. harzianum as promising candidates, exhibiting significant nematicidal activity. Overall, the study underscores the potential of combined biocontrol approaches for nematode management in agricultural settings. However, further research is essential to evaluate practical applications and long-term efficacy. These findings contribute to the development of sustainable alternatives to chemical nematicides, with potential implications for agricultural practices and crop protection strategies.
Assuntos
Bacillus , Raios gama , Controle Biológico de Vetores , Doenças das Plantas , Solanum lycopersicum , Tylenchoidea , Animais , Tylenchoidea/fisiologia , Bacillus/genética , Bacillus/fisiologia , Solanum lycopersicum/parasitologia , Solanum lycopersicum/microbiologia , Doenças das Plantas/parasitologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia , Controle Biológico de Vetores/métodos , Mutação , Hypocreales/genética , Antinematódeos/farmacologia , Agentes de Controle Biológico/farmacologia , Quitosana/farmacologiaRESUMO
A 241Am gamma (γ)-ray calibration field that meets the requirements for a γ-ray reference field as specified in the ISO 4037 standard series was established in the Facility of Radiation Standards of the Japan Atomic Energy Agency. The reference air kerma rates were measured using a reference ionization chamber calibrated by the N-80 quality X-ray calibration field of the national metrology standard in Japan and with a correction to account for differences in photon energy due to the calibration field. Conversion coefficients for the 241Am γ-ray calibration field, including those not listed in the ISO 4037 standard series, were calculated based on the measured γ-ray fluence rate spectra.
Assuntos
Amerício , Raios gama , Calibragem , Amerício/análise , Japão , Padrões de Referência , Doses de Radiação , Monitoramento de Radiação/métodos , Monitoramento de Radiação/normas , Radiometria/normas , Radiometria/métodos , FótonsRESUMO
The radiolytic degradation of 4-hydroxybenzoate (4-HBA-) in aerated, oxygen-free and N2O-saturated aqueous solutions at concentrations of 0.10 and 0.25 mmol/dm3 were gamma irradiated at different doses in a source of Co-60. The results show that ·OH adds predominantly to the 3 position of the aromatic ring, and elimination of the acid group leads to the degradation of 4-HBA-. With an N2O-saturated 0.10 mmol/dm3 4-HBA- solution, total degradation occurred at 1.6 kGy, and with a 0.25 mmol/dm3 solution, total degradation occurred at 3.5 kGy. In the aerated and oxygen-free 0.25 mmol/dm3 4-HBA- solutions, the behavior was similar, degradation occurring at a dose of 13.1 kGy. At the concentration of 0.10 mmol/dm3, total degradation occurred at 7.0 kGy, with small amounts of radiolytic products and byproducts. We propose a mechanism for the degradation of 4-HBA- caused by water radicals produced in the three environments, leading to formation of the identified stable products. Oxidation was followed by chemical oxygen demand (COD), which decreased as the 4-HBA- concentration increased. The kinetics showed a pseudo-first-order behavior. The rate constant of degradation was similar for the solutions with and without oxygen.
Assuntos
Oxigênio , Parabenos , Parabenos/química , Oxigênio/química , Raios gama , Poluentes Químicos da Água/química , Água/química , SoluçõesRESUMO
Prolonged exposure to different occupational or environmental toxicants triggered oxidative stress and inflammatory reactions mediated lung damage. This study was designed to explore the influence and protective impact of flavone on lung injury in rats intoxicated with nicotine (NIC) and exposed to radiation (IR). Forty rats were divided into four groups; group I control, group II flavone; rats were administered with flavone (25 mg/kg/day), group III NIC + IR; rats were injected intraperitoneally with NIC (1 mg/kg/day) and exposed to γ-IR (3.5 Gy once/week for 2 weeks) while group IV NIC + IR + flavone; rats were injected with NIC, exposed to IR and administered with flavone. Redox status parameters and histopathological changes in lung tissue were evaluated. Nuclear factor-kappa B (NF-κB), forkhead box O-class1 (FoxO1) and nucleotide-binding domain- (NOD-) like receptor pyrin domain-containing-3 (NLRP3) gene expression were measured in lung tissues. Moreover, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and phosphatidylinositol three kinase (PI3K) were measured using ELISA kits. Our data demonstrates, for the first time, that flavone protects the lung from NIC/IR-associated cytotoxicity, by attenuating the disrupted redox status and aggravating the antioxidant defence mechanism via activation of the PI3K/Nrf2. Moreover, flavone alleviates pulmonary inflammation by inhibiting the inflammatory signaling pathway FOXO1/NF-κB/NLRP3- Inflammasome. Collectively, the obtained results exhibited a notable efficiency of flavone in alleviating lung injury induced by NIC and IR via modulating PI3K/Nrf2 and FoxO1/NLRP3 Inflammasome.
Assuntos
Flavonas , Inflamassomos , Lesão Pulmonar , Nicotina , Animais , Masculino , Ratos , Flavonas/farmacologia , Proteína Forkhead Box O1 , Raios gama , Inflamassomos/metabolismo , Inflamassomos/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Pulmão/efeitos da radiação , Lesão Pulmonar/metabolismo , Lesão Pulmonar/prevenção & controle , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Nicotina/farmacologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Ratos Wistar , Transdução de Sinais/efeitos dos fármacosRESUMO
Perilla [Perilla frutescens (L.) var frutescens] is a traditional oil crop in Asia, recognized for its seeds abundant in α-linolenic acid (18:3), a key omega-3 fatty acid known for its health benefits. Despite the known nutritional value, the reason behind the higher 18:3 content in tetraploid perilla seeds remained unexplored. Gamma irradiation yielded mutants with altered seed fatty acid composition. Among the mutants, DY-46-5 showed a 27% increase in 18:2 due to the 4-bp deletion of PfrFAD3b, and NC-65-12 displayed a 16% increase in 18:2 due to the loss of function of PfrFAD3a through a large deletion. Knocking out both copies of FATTY ACID DESATURASE3 (PfrFAD3a and PfrFAD3b) simultaneously using CRISPR/Cas9 resulted in an increase in 18:2 by up to 75% and a decrease in 18:3 to as low as 0.3% in seeds, emphasizing the pivotal roles of both genes in 18:3 synthesis in tetraploid perilla. Furthermore, diploid Perilla citriodora, the progenitor of cultivated tetraploid perilla, harbors only PfrFAD3b, with a fatty acid analysis revealing lower 18:3 levels than tetraploid perilla. In conclusion, the enhanced 18:3 content in cultivated tetraploid perilla seeds can be attributed to the acquisition of two FAD3 copies through hybridization with wild-type diploid perilla.
Assuntos
Sistemas CRISPR-Cas , Ácidos Graxos Dessaturases , Raios gama , Ácido Linoleico , Sementes , Tetraploidia , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Sementes/genética , Sementes/efeitos da radiação , Sementes/metabolismo , Ácido Linoleico/metabolismo , Perilla/genética , Perilla/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMO
To establish the radioactivity level of soils and assess the associated radiological impact on residents, 58 samples from the town of Bitola and its environs were collected. After conducting gross alpha and gross beta measurements with a gas-flow proportional counter as a preliminary screening test, subsequent gamma-spectrometry measurements reveal the presence of 40K, 226Ra, 232Th, and 137Cs in the soil samples as radionuclides with the highest impact. The absorbed gamma dose rate, the annual effective dose, radium equivalent activity, external hazard index, gamma index, excess lifetime cancer risk, and annual gonadal dose were calculated using the obtained activity concentrations of the radionuclides. Upon comparison with similar studies conducted in the Balkan countries, the obtained results for radiation hazard indices were found to be the highest in the region. Coloured maps were generated to visually represent the spatial distribution of the absorbed gamma dose rate in air and annual effective dose, clearly indicating the combined influence of geology and human activities, including the nearby thermoelectric power plant operation.