Fungicide azoxystrobin toxicity was monitored by means of a 96-h biotest with Artemia franciscana nauplius stages after exposure to solutions with concentrations of 0.2, 0.4, 0.6 and 0.8 mg L(-1) irradiated with (60)Co gamma radiation with doses of 1, 2.5, 5 and 10 kGy. The effects of ionization radiation on azoxystrobin toxicity were mainly manifested by a statistically significant reduction of lethality after 72- and 96-h exposure. A maximum reduction of lethality of 72 % was achieved using doses of 1-5 kGy for an azoxystrobin initial concentration of 0.4 mg L(-1) and after 72 h of exposure. At a 96-h exposure, a difference of lethal effects reached up to 70 % for a dose of 10 kGy. The observed effect of gamma ionizing radiation on azoxystrobin toxicity suggest that this approach can be applied as an alternative for a reduction of azoxystrobin residua in food.

• Klíčová slova
• 60Co gamma radiation, Biotest, Fungicide azoxystrobin, Nauplius stages Artemia franciscana,
• MeSH
• analýza potravin MeSH
• antifungální látky chemie   toxicita   MeSH
• Artemia účinky léků   účinky záření   MeSH
• ionizující záření MeSH
• kontaminace potravin analýza   MeSH
• LD50 MeSH
• methakryláty chemie   toxicita   MeSH
• potravinářská mikrobiologie MeSH
• pyrimidiny chemie   toxicita   MeSH
• strobiluriny MeSH
• vztah dávky záření a odpovědi MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• záření gama * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antifungální látky MeSH
• azoxystrobin MeSH Prohlížeč
• methakryláty MeSH
• pyrimidiny MeSH
• strobiluriny MeSH

The paper describes a method of pulse height spectrum measurement in a wide energy range. The LVR‑15 research reactor building was chosen to demonstrate this method. Pulse height spectra were measured on the third floor of the reactor building. Two types of scintillation detectors, NaI (Tl) and a plastic scintillator, were used. The detectors were placed for about 25 m from the reactor core, thus, separated from the primary circuit water in the reactor pool, biological shielding, building wall and other constructional materials. Spectra were measured in a wide energy range from 30 keV to 1000 MeV, in which signals were recorded from natural and man-made radionuclides, prompt gamma radiation and cosmic radiation. Experimental data were collected both while the reactor was in operation and while it was out of operation. This study confirms that differences in these spectra can be detected remotely over relatively large distances from the reactor core by adequately simple detection means.

• MeSH
• dávka záření MeSH
• konstrukční materiály MeSH
• kosmické záření * MeSH
• lidé MeSH
• plastické hmoty MeSH
• scintilace - počítání přístrojové vybavení   metody   MeSH
• záření gama * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• plastické hmoty MeSH

A collection of personal radiation shielding protective clothing, suitable for use in case of accidents in nuclear facilities or radiological emergency situations involving radioactive agents, was gathered and tested at the Nuclear Protection Department of the National Institute for Nuclear, Chemical and Biological Protection, Czech Republic. Attenuating qualities of shielding layers in individual protective clothing were tested via spectra measurement of x and gamma rays, penetrating them. The rays originated from different radionuclide point sources, the gamma ray energies of which cover a broad energy range. The spectra were measured by handheld spectrometers, both scintillation and High Purity Germanium. Different narrow beam geometries were adjusted using a special testing bench and a set of various collimators. The main experimentally determined quantity for individual samples of personal radiation shielding protective clothing was x and gamma rays attenuation for significant energies of the spectra. The attenuation was assessed comparing net peak areas (after background subtraction) in spectra, where a tested sample was placed between the source and the detector, and corresponding net peak areas in spectra, measured without the sample. Mass attenuation coefficients, which describe attenuating qualities of shielding layers materials in individual samples, together with corresponding lead equivalents, were determined as well. Experimentally assessed mass attenuation coefficients of the samples were compared to the referred ones for individual heavy metals.

• MeSH
• dávka záření MeSH
• first responder * MeSH
• fotony MeSH
• germanium MeSH
• lidé MeSH
• ochranné oděvy * MeSH
• plánování postupu v případě katastrof metody   MeSH
• radiační ochrana metody   MeSH
• radiační poranění prevence a kontrola   MeSH
• rentgenové záření MeSH
• software MeSH
• těžké kovy MeSH
• únik radioaktivních látek * MeSH
• záření gama MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• germanium MeSH
• těžké kovy MeSH

Localization of size-limited gamma-ray anomalies plays a fundamental role in uranium prospecting and environmental studies. Possibilities of a newly developed mini-airborne gamma-ray spectrometric equipment were tested on a uranium anomaly near the village of Třebsko, Czech Republic. The measurement equipment was based on a scintillation gamma-ray spectrometer specially developed for unmanned aerial vehicles (UAV) mounted on powerful hexacopter. The gamma-ray spectrometer has two 103 cm3 BGO scintillation detectors of relatively high sensitivity. The tested anomaly, which is 80 m by 40 m in size, was investigated by ground gamma-ray spectrometric measurement in a detail rectangular measurement grid. Average uranium concentration is 25 mg/kg eU attaining 700 mg/kg eU locally. The mini-airborne measurement across the anomaly was carried out on three 100 m long parallel profiles at eight flight altitudes from 5 to 40 m above the ground. The resulting 1 s 1024 channel gamma-ray spectra, recorded in counts per second (cps), were processed to concentration units of K, U and Th, while total count (TC) was reported in cps. Increased gamma ray intensity of the anomaly was indicated by mini-airborne measurement at all profiles and altitudes, including the highest altitude of 40 m, at which the recorded intensity is close to the natural radiation background. The reported instrument is able to record data with comparable quality as standard airborne survey, due to relative sensitive detector, lower flight altitude and relatively low flight speed of 1 m/s. The presented experiment brings new experience with using unmanned semi-autonomous aerial vehicles and the latest mini-airborne radiometric instrument. The experiment has demonstrated the instrument's ability to localize size-limited uranium anomalies.

• MeSH
• monitorování radiace metody   MeSH
• nadmořská výška MeSH
• radioaktivní látky znečišťující vzduch analýza   MeSH
• spektrometrie gama * MeSH
• uran analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• radioaktivní látky znečišťující vzduch MeSH
• uran MeSH

• Klíčová slova
• RADIATION EFFECTS/experimental *, VITAMIN A/radiation effects *, VITAMIN C/radiation effects *,
• MeSH
• kyselina askorbová účinky záření   MeSH
• radiační účinky * MeSH
• thiamin * MeSH
• vitamin A účinky záření   MeSH
• vitaminy * MeSH
• záření gama * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyselina askorbová MeSH
• thiamin * MeSH
• vitamin A MeSH
• vitaminy * MeSH

Fluorometric analysis of DNA unwinding (FADU)-a sensitive technique for the detection of strand breaks in DNA-has been modified and used for the detailed investigation of repair kinetics of DNA-strand breaks arising under different conditions in Ehrlich ascites tumour (EAT) cells irradiated by gamma-rays or ultraviolet (UV) radiation. The repair kinetics of DNA-strand breaks induced in EAT cells by gamma-radiation was measured at radiation doses of 8, 20 and 50 Gy. We found complex repair curves in all cases, probably reflecting the combined processes of break rejoining and break generation during repair. In order to affect the above-mentioned processes, we have used different conditions of repair and different types of radiation. Lowering of the temperature of incubation and treating the cells by 5-fluoro-2'-deoxyuridine (FUdR) lead to complex changes of the repair curve with a reduced "wave" pattern. In order to change the type of damage to DNA, we used UV radiation (254 nm, 10 and 20 J/m2). Detailed studies of the repair kinetics showed that the repair curve for 10 J/m2 had a second maximum within 70 min after irradiation.

• MeSH
• DNA účinky záření   MeSH
• Ehrlichův tumor MeSH
• kalibrace MeSH
• kinetika MeSH
• oprava DNA * MeSH
• poškození DNA * MeSH
• ultrafialové záření MeSH
• vztah dávky záření a odpovědi MeSH
• záření gama MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH

Most plant research focuses on the responses immediately after exposure to ionizing irradiation (IR). However, it is as important to investigate how plants recover after exposure since this has a profound effect on future plant growth and development and hence on the long-term consequences of exposure to stress. This study aimed to investigate the IR-induced responses after exposure and during recovery by exposing 1-week old A. thaliana seedlings to gamma dose rates ranging from 27 to 103.7 mGy/h for 2 weeks and allowing them to recover for 4 days. A high-throughput RNAsequencing analysis was carried out. An enrichment of GO terms related to the metabolism of hormones was observed both after irradiation and during recovery at all dose rates. While plants exposed to the lowest dose rate activate defence responses after irradiation, they recover from the IR by resuming normal growth during the recovery period. Plants exposed to the intermediate dose rate invest in signalling and defence after irradiation. During recovery, in the plants exposed to the highest dose rate, fundamental metabolic processes such as photosynthesis and RNA modification were still affected. This might lead to detrimental effects in the long-term or in the next generations of those irradiated plants.

• MeSH
• Arabidopsis * MeSH
• monitorování radiace * MeSH
• rostliny MeSH
• semenáček účinky záření   MeSH
• záření gama MeSH
• Publikační typ
• časopisecké články MeSH

AIMS: This study evaluates the effectiveness of two standard sterilization methods on microorganisms in bentonite, which is proposed as a buffer around metal canisters containing long-lived radioactive waste. Bentonite, as a natural clay, contains microorganisms with enhanced resistance to harsh conditions and the ability to reactivate upon decompaction. Sterile controls are crucial in experiments estimating the impact of microorganisms on nuclear waste repositories. Yet, the effectiveness of common sterilization methods on bentonite microorganisms has not been fully evaluated. METHODS AND RESULTS: Two methods were compared: dry heat (nine cycles at 121°C for 4 h) and gamma irradiation (10-140 kGy at 147 Gy·min-1). Molecular-genetic, microscopic, and cultivation techniques were used to assess sterilization. Heat sterilization did not eliminate heat-resistant microorganisms, such as Bacillus, Paenibacillus, and Terribacillus, from bentonite powder even after nine heat cycles. However, bentonite suspended in deionized water was sterile after four heat cycles. In contrast, gamma irradiation effectively reduced microbial survivability above a dose of 10 kGy, with the highest doses (100-140 kGy) potentially degrading DNA. CONCLUSIONS: Gamma irradiation at 30 kGy effectively sterilized bentonite powder. The findings of our experiments emphasize the importance of using appropriate sterilization methods to maintain sterile controls in experiments that evaluate the microbial impacts in nuclear waste repositories. However, further assessment is needed to determine the effects of potential alterations induced by gamma radiation on bentonite properties.

• Klíčová slova
• abiotic stress, hazardous waste, microbial diversity, radiation, sterilization,
• MeSH
• Bacteria účinky záření   izolace a purifikace   MeSH
• bentonit * MeSH
• radioaktivní odpad * analýza   MeSH
• sterilizace * metody   MeSH
• vysoká teplota * MeSH
• záření gama * MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• bentonit * MeSH
• radioaktivní odpad * MeSH

Male rats of the Wistar strain were continuously irradiated with an exposure of 0.57 Gy (60 R) of gamma-rays from a 60Co source. Irradiation lasted from 1 to 50 days in an experimental field, in which control animals shielded from radiation were also placed. After a 16-h starvation, concentration of glucose in the blood and of glycogen in the liver and heart was determined 1, 3, 7, 14, 21, 25, 32, 39 and 50 days after the beginning of irradiation. Concentration of blood glucose in irradiated rats did not practically differ from that of control animals during the whole period of investigation. Concentration of liver glycogen in irradiated animals was higher than that of the controls during all time intervals, except for day 1. Values of glycogen in the heart muscle were approximately identical in irradiated and control rats, except for day 21, on which they sharply increased in the irradiated animals. In addition to the investigation of blood glucose and tissue glycogen during continuous irradiation, we followed these parameters immediately, and 1, 6 and 12 months after continuous irradiation with a daily exposure of 0.57 Gy (60 R) up to a total exposure of 14.35 Gy (1 500 R) of gamma-rays. Considerably higher values of liver glycogen were detected in irradiated rats immediately and 1 and 6 months after the end of irradiation.

• MeSH
• dávka záření MeSH
• glykogen účinky záření   MeSH
• jaterní glykogen metabolismus   účinky záření   MeSH
• krevní glukóza účinky záření   MeSH
• krysa rodu Rattus MeSH
• myokard metabolismus   MeSH
• omezení příjmu potravy MeSH
• svaly metabolismus   MeSH
• záření gama MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glykogen MeSH
• jaterní glykogen MeSH
• krevní glukóza MeSH

The primary objective of this research was to study the transmission of gamma radiation from heavyweight concrete containing barite aggregates. For this purpose, cylindrical and cubic specimens were produced for 10 mix designs. The mix designs containing different percentages of barite aggregates were calculated; five mix designs were also calculated for the compressive strength of 25 MPa, while five of them were designed for the compressive strength of 35 MPa to study the influence of the compressive strength rate on the reduction in gamma radiation transmission. The results indicated that both compressive and tensile strength was decreased by increasing the ratio of barite aggregates. The rate in reduction of compressive strength and especially tensile strength in concrete C35 was less than in concrete C25. The use of barite aggregates increased the attenuation coefficient of concrete. The attenuation coefficient in C35 concrete increased more than that in C25 upon increasing the amount of barite aggregate. By increasing the thickness of concrete with different percentages of barite, the rate of radiation loss in different samples was closer. The difference in the rate of radiation loss at a thickness of 150 mm was not much different from that at a thickness of 100 mm, whereas it was considerably decreased at a thickness of 300 mm. The test results indicated that the reduction in the gamma transmission rate is significantly dependent on the density of concrete.

• Klíčová slova
• attenuation coefficient, barite aggregates, gamma radiation, heavyweight concrete,
• Publikační typ
• časopisecké články MeSH