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1.
Appl Radiat Isot ; 206: 111234, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38412772

ABSTRACT

A practical and comprehensive experimental approach for radioactivity measurements of voluminous environmental samples using high-resolution gamma-ray spectrometry with High Purity Germanium (HPGe) detector is presented. The radioanalytical procedure includes sample preparation, detector calibration, implemented corrections, quality control and assurance; and it is demonstrated with the determination of natural and anthropogenic radionuclides in water and soil standard samples. The methodology is verified, and the results are validated by intercomparison with the refence values provided as part of a worldwide proficiency test.

3.
J Environ Radioact ; 251-252: 106964, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35863270

ABSTRACT

A coupled hydrodynamic/lagrangian particle drift model was applied to obtain the distribution of key radionuclides that are dispersed at the surface water (upper 100 m) of Eastern Mediterranean Sea, in case of an accident of Nuclear Power Plant at Akkuyu. The model was applied to simulate the dispersion of key artificial radionuclide concentration, in case of a hypothetical accident to assess issues related to sea health and potential hazards. The released radionuclide was found to have a favorable westward direction, following the prevailing currents. The variability of the predicted pattern is interpreted according to the near surface circulation patterns in the study area. The dispersion of key radionuclides (137Cs, 238Pu and 131I) was studied in a spatial and temporal manner at the neighboring coasts of the location of the NPP. Furthermore, the fate of the plume was predicted for each month after the accident date close to the areas of Akkuyu, namely Cyprus, Rhodes Island, North Cretan coast, Cyclades and Syrian Coast. The annual study revealed that the radioactive plume is present with high concentration (maximum values of 1200 Bq m-3 for the long lived isotopes and 600 Bq m-3 for 131I) in the location of the plant for short period of time (1-2 months), while the other areas are affected during the whole year with low level of activity concentration (20-50 Bqm-3). The ERICA Assessment Tool was also used to evaluate dose rates to common marine biota at the studied areas.


Subject(s)
Fukushima Nuclear Accident , Radiation Monitoring , Water Pollutants, Radioactive , Accidents , Cesium Radioisotopes/analysis , Iodine Radioisotopes , Mediterranean Sea , Nuclear Power Plants , Water Pollutants, Radioactive/analysis
4.
Appl Radiat Isot ; 160: 109124, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32174467

ABSTRACT

The calibration of an underwater spectrometer, consisting of a CeBr3 crystal, is performed for sediment sample measurements, via experimental data and Monte Carlo simulations. The system was implemented for activity concentration measurements in marine sediment samples in the laboratory. The results were compared with corresponding high resolution measurements and showed that the system provides accurate results, but relatively high uncertainties. Different measurement geometries are theoretically studied via Monte Carlo simulations in order to improve the system performance for such measurements.

5.
Appl Radiat Isot ; 145: 198-204, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30641433

ABSTRACT

Natural radionuclides, present in mining materials, can exhibit elevated values, thus it is of great interest to study their dispersion in mining areas. Radionuclide spatial variations were determined in coastal surface sediments near the mining area of Ierissos Gulf in northern Greece. 226Ra and 235U measured concentrations were compared with the estimations of ERICA Tool, the dispersion patterns were derived and the affected region around the load-out pier area was calculated to be approximately 21 km2.

6.
Appl Radiat Isot ; 121: 44-50, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28024218

ABSTRACT

A methodology based on γ-spectrometry measurements of untreated coastal water samples is proposed for the direct estimation of coastal residence time of submarine discharged groundwater. The method was applied to a submarine spring at Stoupa Bay covering all seasons. The estimated residence time exhibited an annual mean of 4.6±1.7 d. An additional measurement using the in situ underwater γ-spectrometry technique was performed, in the same site. The in situ method yielded a value of 2.8±0.2 d that was found consistent with the corresponding value derived using the developed lab-based method (3.4±2.0 d) for the same period.

7.
J Environ Radioact ; 164: 47-59, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27420593

ABSTRACT

A new approach for calibrating an in situ detection system for measurements in marine sediments has been developed. The efficiency calibration was deduced on full spectral range by Monte Carlo simulations (MCNP5 code) considering a close detector-seabed geometry set-up. Moreover, the influence of the detection efficiency with respect to the variations of the sediment geological characteristics was studied through Monte Carlo simulations. The results of the theoretical approach were compared with experimental calculations in two different real test cases, yielding a satisfactory agreement (up to 10% and 20% for sites 1 and 2 respectively) in the energy range from 351 keV to 2614 keV. For the experimental measurements, the in situ detection system KATERINA was deployed both in the seawater and on the seabed in two different marine environments. The experimental determinations of the detection efficiency were performed by utilizing the acquired data of the deployments, along with additional necessary laboratory measurements. The adopted approach and the obtained results are discussed.


Subject(s)
Computer Simulation , Monte Carlo Method , Radiation Monitoring/methods , Geologic Sediments/analysis , Seawater/analysis , Spectrometry, Gamma
8.
Appl Radiat Isot ; 116: 22-33, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27474903

ABSTRACT

Marine sediment samples were collected from Ierissos Gulf, N Aegean Sea, close to the coastal mining facilities. Measurements of radionuclide and metal concentrations, mineral composition and grain size distribution were performed. The concentrations of (226)Ra, (235)U and trace metals showed enhanced values in the port of Stratoni compared with those obtained near to Ierissos port. The dose rates received by marine biota were also calculated by the ERICA Assessment Tool and the results indicated no significant radiological risk.


Subject(s)
Geologic Sediments/analysis , Geologic Sediments/chemistry , Industrial Waste/analysis , Metals/analysis , Mining , Radioactive Waste/analysis , Radioisotopes/analysis , Greece , Metals/chemistry , Reproducibility of Results , Sensitivity and Specificity
9.
Appl Radiat Isot ; 114: 76-86, 2016 08.
Article in English | MEDLINE | ID: mdl-27213807

ABSTRACT

The Full Spectrum Analysis approach was applied to obtain activity concentration estimations for in situ measurements in the marine environment. The 'standard spectra' were reproduced using the MCNP-CP code. In order to extract the activity concentrations, χ(2) minimization calculations were performed by implementing the MINUIT code. The method was applied to estimate the activity concentrations for measurements in the marine environment in three different test cases. The estimated activity concentrations were in good agreement with the experimentally derived ones within uncertainties.


Subject(s)
Radioisotopes/analysis , Spectrometry, Gamma/methods , Water Pollutants, Radioactive/analysis , Algorithms , Calibration , Computer Simulation , Cyprus , Greece , Humans , Monte Carlo Method , Radiation Monitoring/methods , Seawater/analysis
10.
J Environ Radioact ; 157: 1-15, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26945883

ABSTRACT

Tigris and Euphrates rivers both emerge in eastern Turkey and cross Syria and Iraq. They unite to Shatt al-Arab/Arvand Rud River and discharge in Arabic/Persian Gulf. The activity concentration of natural and anthropogenic radionuclides was measured during the August of 2011 in a number of surficial sediment samples collected from the seabed along an almost straight line beginning near the estuary mouth and extending seaward. The results exhibited low activity concentration levels and an almost homogeneous spatial distribution except locations where sediment of biogenic origin, poor in radionuclides, dilute their concentrations. Dose rates absorbed by reference marine biota were calculated by the ERICA Assessment Tool considering the contribution of 40 K. The results revealed a relatively low impact of 40 K mainly to species living in, on and close to the seabed. Also, statistical association of radionuclides with selected stable elements (Ca, Ba and Sr) did not indicate presence of by-products related with oil and gas exploitation and transportation activities. Moreover, a semi-empirical sedimentology model applied to reproduce seabed granulometric facies based entirely on radionuclides activity concentrations.


Subject(s)
Geologic Sediments/analysis , Radioisotopes/analysis , Water Pollutants, Radioactive/analysis , Animals , Crustacea , Fishes , Indian Ocean , Mollusca , Phytoplankton , Polychaeta , Radiation Dosage , Radiation Monitoring , Zooplankton
11.
Am J Transplant ; 16(4): 1319-22, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26555407

ABSTRACT

The use of everolimus (EVL) as primary immunosuppression is steadily increasing in heart transplantation (HTx) patients. Limited data currently exist in kidney transplantation, but there is no report of EVL use during pregnancy after HTx and its pharmacokinetics in the newborn. We report a case of an unplanned pregnancy discovered at 21 weeks of gestation in a female HTx patient aged 40 years treated with EVL and cyclosporine (CyA). Because pregnancy was advanced, immunosuppression therapy was left unchanged. At 36 weeks, a healthy infant was delivered. At birth, CyA blood levels were lower in the neonate, but EVL concentrations in maternal and neonatal umbilical blood were similar. Amniotic fluid concentrations were undetectable for both drugs. In the newborn, EVL was measurable at 5 days after birth, whereas CyA disappeared within 2 days. Cord blood displayed a normal count of B and T cells and CD4, CD8 and natural killer cell populations. At birth, both mother and newborn displayed the same blood levels of EVL; therefore, a filter effect of the placenta may be hypothesized for CyA but not for EVL. No immediate complications were observed with this pregnancy.


Subject(s)
Everolimus/therapeutic use , Heart Transplantation , Immunosuppressive Agents/therapeutic use , Postoperative Complications , Adult , Cyclosporine/blood , Cyclosporine/pharmacokinetics , Cyclosporine/therapeutic use , Everolimus/blood , Everolimus/pharmacokinetics , Female , Graft Survival , Heart Diseases/surgery , Humans , Immunosuppressive Agents/blood , Immunosuppressive Agents/pharmacokinetics , Infant, Newborn , Pregnancy , Pregnancy Outcome , Tissue Distribution
12.
Sci Total Environ ; 533: 133-43, 2015 Nov 15.
Article in English | MEDLINE | ID: mdl-26151657

ABSTRACT

A radiological model for (137)Cs and (90)Sr dispersion in the marine environment of the Thermaikos Gulf, Greece, and the river catchments draining into the Gulf, is presented. The model, developed and implemented within the MOIRA-PLUS decision support system, integrates appropriate site-specific information. The model's performance has been tested using the available empirical (137)Cs activity concentration data in abiotic and biotic components of the gulf since the Chernobyl accident. Further, this paper describes the results of a modelling exercise performed within the IAEA's EMRAS II international modelling programme to estimate the environmental sensitivity of this characteristic Mediterranean coastal marine environment following radioactive contamination. The radiation doses to humans after a single hypothetical instantaneous deposition of 1000 Bq m(-2), assuming that all of their food intake from the marine pathway comes from the local environment, were calculated. The obtained results are consistent with estimates from other models for different coastal marine environments in the frame of the above-mentioned EMRAS exercise.


Subject(s)
Cesium Radioisotopes/analysis , Models, Chemical , Radiation Monitoring/methods , Strontium Radioisotopes/analysis , Water Pollutants, Radioactive/analysis , Greece
13.
Appl Radiat Isot ; 101: 83-92, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25846455

ABSTRACT

Activity concentration measurements were carried out on the seabed, by implementing the underwater detection system KATERINA. The efficiency calibration was performed in the energy range 350-2600 keV, using in situ and laboratory measurements. The efficiency results were reproduced and extended in a broadened range of energies from 150 to 2600 keV, by Monte Carlo simulations, using the MCNP5 code. The concentrations of (40)K, (214)Bi and (208)Tl were determined utilizing the present approach. The results were validated by laboratory measurements.

14.
Appl Radiat Isot ; 82: 268-78, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24103707

ABSTRACT

The in-situ underwater gamma-ray spectrometry method is validated by inter-comparison with laboratory method. Deployments of the spectrometer KATERINA on a submarine spring and laboratory measurements of water samples with HPGe detector were performed. Efficiency calibrations, Monte Carlo simulations and the Minimum Detectable Activity (MDA) estimations were realized. MDAs varied from 0.19 to 10.4 (lab) and 0.05 to 0.35 (in-situ) Bq/L, while activity concentrations differed from 7% (for radon progenies) up to 10% (for (40)K), between the two methods.


Subject(s)
Radiation Monitoring/methods , Spectrometry, Gamma/methods , Water Pollutants, Radioactive/analysis , Calibration , Computer Simulation , Greece , Humans , Limit of Detection , Monte Carlo Method , Radiation Monitoring/instrumentation , Radiation Monitoring/statistics & numerical data , Radioisotopes/analysis , Seawater/analysis , Spectrometry, Gamma/instrumentation , Spectrometry, Gamma/statistics & numerical data
16.
J Environ Radioact ; 122: 1-8, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23517769

ABSTRACT

This paper describes modelling calculations carried out to determine the sensitivity of various rural and semi-natural environments to radionuclide contamination by (137)Cs, (90)Sr, and (131)I released during a major nuclear accident. Depositions of 1000 Bq/m(3) were assumed for each radionuclide. Four broad types of environments were considered: agricultural, forest or tundra, freshwater aquatic, and coastal marine. A number of different models were applied to each environment. The annual dose to a human population receiving most or all of its food and drinking water from a given environment was taken as a broad measure of sensitivity. The results demonstrated that environmental sensitivity was highly radionuclide specific, with (137)Cs generally giving the highest doses during the first year, especially for adults, in terrestrial and freshwater pathways. However, in coastal marine environments, (131)I and (239)Pu were more significant. Sensitivity was time dependent with doses for the first year dominating those for the 2nd and 10th years after deposition. In agricultural environments the ingestion dose from (137)Cs was higher for adults than other age groups, whereas for (90)Sr and (131)I, the ingestion dose was highest for infants. The dependence of sensitivity on social and economic factors such as individual living habits, food consumption preferences, and agricultural practices is discussed.


Subject(s)
Models, Theoretical , Radioactive Pollutants/analysis , Adult , Agriculture , Cesium Radioisotopes/analysis , Cesium Radioisotopes/toxicity , Food Contamination, Radioactive/analysis , Humans , Infant , Iodine Radioisotopes/analysis , Iodine Radioisotopes/toxicity , Radioactive Pollutants/toxicity , Soil Pollutants, Radioactive/analysis , Soil Pollutants, Radioactive/toxicity , Strontium Radioisotopes/analysis , Strontium Radioisotopes/toxicity , Trees , Water Pollutants, Radioactive/analysis , Water Pollutants, Radioactive/toxicity
17.
BJOG ; 120(4): 463-71, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23194157

ABSTRACT

OBJECTIVE: This contribution addresses the risk associated with exposure to statins during pregnancy. DESIGN: Multicentre observational prospective controlled study. SETTING: European Network of Teratology Information Services. POPULATION: Pregnant women who contacted one of 11 participating centres, seeking advice about exposure to statins during pregnancy, or to agents known to be nonteratogenic. METHODS: Pregnancies exposed during first trimester to statins were followed up prospectively, and their outcomes were compared with a matched control group. MAIN OUTCOME MEASURES: Rates of major birth defects, live births, miscarriages, elective terminations, preterm deliveries and gestational age and birthweight at delivery. RESULTS: We collected observations from 249 exposed pregnancies and 249 controls. The difference in the rate of major birth defects between the statin-exposed and the control groups was small and statistically nonsignificant (4.1% versus 2.7% odds ratio [OR] 1.5; 95% confidence interval [95% CI] 0.5-4.5, P = 0.43). In an adjusted Cox model, the difference between miscarriage rates was also small and not significant (hazard ratio 1.36, 95% CI 0.63-2.93, P = 0.43). Premature birth was more frequent in exposed pregnancies (16.1% versus 8.5%; OR 2.1, 95% CI 1.1-3.8, P = 0.019). Nonetheless, median gestational age at birth (39 weeks, interquartile range [IQR] 37-40 versus 39 weeks, IQR 38-40, P = 0.27) and birth weight (3280 g, IQR 2835-3590 versus 3250 g, IQR 2880-3630, P = 0.95) did not differ between exposed and non-exposed pregnancies. CONCLUSIONS: This study did not detect a teratogenic effect of statins. Its statistical power remains insufficient to challenge current recommendations of treatment discontinuation during pregnancy.


Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Maternal Exposure/adverse effects , Pregnancy Outcome/epidemiology , Teratogens , Abnormalities, Drug-Induced/epidemiology , Abortion, Induced/statistics & numerical data , Abortion, Spontaneous/epidemiology , Adult , Birth Rate , Case-Control Studies , Europe/epidemiology , Female , Humans , Infant, Newborn , Infant, Newborn, Diseases/epidemiology , Maternal Age , Pregnancy , Pregnancy Trimester, First , Premature Birth/epidemiology , Prospective Studies , Risk Factors
18.
Clin Exp Obstet Gynecol ; 39(4): 535-6, 2012.
Article in English | MEDLINE | ID: mdl-23444763

ABSTRACT

Clomiphene is widely used for inducing ovulation. Evidence for congenital abnormalities, in particular central nervous system defects (CNS-D) and in babies born from clomiphene-induced pregnancies is conflicting. The authors report a case of holoprosencephalia (HPE) in a fetus delivered from a mother receiving clomiphene.


Subject(s)
Fetal Diseases/etiology , Holoprosencephaly/etiology , Ovulation Induction , Adult , Clomiphene/adverse effects , Clomiphene/pharmacology , Female , Fertility Agents, Female/adverse effects , Fertility Agents, Female/pharmacology , Fetal Diseases/chemically induced , Fetal Diseases/diagnostic imaging , Holoprosencephaly/chemically induced , Holoprosencephaly/diagnostic imaging , Humans , Ultrasonography, Prenatal
19.
Appl Radiat Isot ; 65(4): 445-53, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17215129

ABSTRACT

Sediment samples have been collected in the Butrint area, located in the south-west Albania to determine the radioactivity levels of (40)K, (137)Cs, (212)Bi, (212)Pb, (214)Bi, (214)Pb, (226)Ra and (228)Ac on the bed of the lagoon and adjacent sea, using direct counting gamma spectroscopy. The concentration of (137)Cs and (40)K varied from 2.8 to 37.5 Bq/kg and from 266 to 675 Bq/kg dry weight (dw), respectively (central values). The average concentrations of (238)U and (232)Th daughter products varied from 8 to 27 Bq/kg and from 13 to 40 Bq/kg dw, respectively. The measured (235)U activity ranged from 0.7 to 2.5 Bq/kg dw. Samples of different sedimentary properties, studied for the radioactivity concentration, revealed an inversely proportional relation between grain size and a linear combination of measured specific activities of (226)Ra, (232)Th ((228)Ac, (212)Bi and (212)Pb), (40)K and (137)Cs.


Subject(s)
Background Radiation , Geologic Sediments/analysis , Radioisotopes/analysis , Seawater/chemistry , Water Pollution, Radioactive/analysis , Albania , Particle Size , Spectrometry, Gamma
20.
Biopharm Drug Dispos ; 19(8): 523-30, 1998 Nov.
Article in English | MEDLINE | ID: mdl-9840214

ABSTRACT

The objective of this study was to evaluate the effects which hydroxypropylmethylcellulose (HPMC) may exert on oral drug absorption, in cases where this soluble fiber is administered to regulate blood lipid levels. Studies were conducted in vitro and in healthy female mongrel dogs using two different grades of HPMC, i.e. K8515 HPMC and ultra high molecular weight (UHMW) HPMC. The maximum plasma concentration, Cmax, of paracetamol and both the Cmax and the area under the concentration-time curve, AUC, of cimetidine were significantly decreased by the coadministration of 10 g of K8515 HPMC or 7.5 g of UHMW HPMC dissolved in 500 mL normal saline under fasting conditions. No statistically significant effects were observed on hydrochlorothiazide or mefenamic acid absorption. Based on in vitro data and previous studies it appears that reductions in gastric emptying and dissolution rate of paracetamol account for the effect observed in vivo. For cimetidine, a drug which can be absorbed from both the small and the large intestine, the indigestibility of HPMC in the colon in addition to the great reduction of dissolution rate led to reductions of both the Cmax and AUC values. The long Tmax values, even in the absence of HPMCs and the more modest reduction of the dissolution rate of hydrochlorothiazide by the HPMCs are thought to have precluded the observation of any significant alterations in the in vivo absorption profile. Owing to its erratic absorption, no statistically based conclusion could be drawn about the effects of coadministered HPMC on the oral absorption of the poorly soluble mefenamic acid. It is concluded that the effects of HPMCs on drug absorption in dogs are most pronounced for compounds with absorption profiles that are dependent on gastric emptying, i.e. compounds that are highly water soluble and that exhibit short Tmax values. Compounds with long absorption profiles appear to be less susceptible to changes in absorption behavior due to coadministration of HPMCs.


Subject(s)
Anticholesteremic Agents/pharmacology , Intestinal Absorption/drug effects , Methylcellulose/analogs & derivatives , Animals , Anticholesteremic Agents/administration & dosage , Area Under Curve , Diffusion , Dogs , Drug Interactions , Hypromellose Derivatives , Methylcellulose/administration & dosage , Methylcellulose/pharmacology , Solubility , Solutions , Viscosity
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