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1.
BMC Gastroenterol ; 24(1): 172, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38760679

ABSTRACT

BACKGROUND: Hospital re-admission for persons with Crohn's disease (CD) is a significant contributor to morbidity and healthcare costs. We derived prediction models of risk of 90-day re-hospitalization among persons with CD that could be applied at hospital discharge to target outpatient interventions mitigating this risk. METHODS: We performed a retrospective study in persons with CD admitted between 2009 and 2016 for an acute CD-related indication. Demographic, clinical, and health services predictor variables were ascertained through chart review and linkage to administrative health databases. We derived and internally validated a multivariable logistic regression model of 90-day CD-related re-hospitalization. We selected the optimal probability cut-point to maximize Youden's index. RESULTS: There were 524 CD hospitalizations and 57 (10.9%) CD re-hospitalizations within 90 days of discharge. Our final model included hospitalization within the prior year (adjusted odds ratio [aOR] 3.27, 95% confidence interval [CI] 1.76-6.08), gastroenterologist consultation within the prior year (aOR 0.185, 95% CI 0.0950-0.360), intra-abdominal surgery during index hospitalization (aOR 0.216, 95% CI 0.0500-0.934), and new diagnosis of CD during index hospitalization (aOR 0.327, 95% CI 0.0950-1.13). The model demonstrated good discrimination (optimism-corrected c-statistic value 0.726) and excellent calibration (Hosmer-Lemeshow goodness-of-fit p-value 0.990). The optimal model probability cut point allowed for a sensitivity of 71.9% and specificity of 70.9% for identifying 90-day re-hospitalization, at a false positivity rate of 29.1% and false negativity rate of 28.1%. CONCLUSIONS: Demographic, clinical, and health services variables can help discriminate persons with CD at risk of early re-hospitalization, which could permit targeted post-discharge intervention.


Subject(s)
Crohn Disease , Patient Readmission , Humans , Crohn Disease/therapy , Crohn Disease/diagnosis , Patient Readmission/statistics & numerical data , Female , Male , Retrospective Studies , Adult , Risk Assessment , Middle Aged , Patient Acceptance of Health Care/statistics & numerical data , Logistic Models , Young Adult
2.
Sci Rep ; 14(1): 5370, 2024 03 04.
Article in English | MEDLINE | ID: mdl-38438444

ABSTRACT

Health Canada (HC) has, since 2013, issued safety alerts restricting the use of codeine-containing drugs among breastfeeding women and children/adolescents under 18 years of age. These products are linked to breathing problems among ultra-rapid CYP2D6 metabolizers and early use of opioid can lead to future opioid misuse. Using a multi-province population-based cohort study, we estimate the impact of federal safety alerts on annual rates of codeine use in the Canadian pediatric population. We analyzed data from 8,156,948 children/adolescents in five Canadian provinces between 1996 and 2021, using a common protocol. Children/adolescents were categorized as: ≤ 12 years (children) or > 12 years (adolescents). We defined codeine exposure by ≥ 1 prescription filled for codeine alone or combined with other medications. For both age categories, we obtained province-specific codeine prescription filling rates per calendar year by dividing the number of children/adolescents with ≥ 1 codeine prescription filled by the number of person-time. Annual rates of codeine use per 1000 persons vary by province from 3.0 (Quebec) to 10.1 (Manitoba) in children, and from 5.5 to 51.3 in adolescents. After the 2013 HC advisory, exposure decreased in all provinces (adjusted level change from - 0.6 to - 18.4%) in children and from - 2.1 to - 17.9% in adolescents after the 2016 advisory. Annual rates declined over time in all provinces, following HC safety alerts specific to each of the two age categories.


Subject(s)
Codeine , Opioid-Related Disorders , Child , Adolescent , Humans , Female , Canada/epidemiology , Codeine/adverse effects , Prevalence , Cohort Studies
3.
Sci Rep ; 14(1): 1224, 2024 Jan 12.
Article in English | MEDLINE | ID: mdl-38216583

ABSTRACT

RadioLab is an Italian project, addressed to school-age people, and designed for the dissemination of scientific culture on the theme of environmental radioactivity, with particular regards to the importance of knowledge of radon gas exposure. The project is a nationwide initiative promoted by the National Institute of Nuclear Physics- INFN. First tool used by the project, and of immediate impact to assess the public awareness on radon, is the administration of the survey "do you know the radon gas?". In the survey, together with the knowledge of radon and of its sources, information on personal, cultural and territorial details regarding the interviewees are also taken. Reasonably, the survey invests not only young people, but also their relatives, school workers and, gradually, the public. The survey is administrated during exhibitions or outreach events devoted to schools, but also open to the public. The survey is in dual form: printed and online. The online mode clearly leads RadioLab project even outside the school environment. Based on the results of the survey, several statistical analyses have been performed and many conclusions are drawn about the knowledge of the population on the radon risk. The RadioLab benefit and the requirement to carry on the project goals, spreading awareness of environmental radioactivity from radon, emerge. The dataset involves all twenty Italian regions and consists of 28,612 entries covering the 5-year period 2018-2022.

4.
Appl Radiat Isot ; 200: 110981, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37633189

ABSTRACT

Irradiation of blood bags using X-ray irradiators and dosimetry services are required to ensure uniform dose levels in the range 25-50 Gy to prevent Transfusion Associated Graft versus Host Disease (TA-GvHD). An absorbed dose characterization of a Raycell MK2 X-Irradiator was performed using three different dosimetric systems. Results showed a dosimetric accuracy of the ionization chamber together with the Alanine dosimeter. TLDs measurements exhibited a small overestimation by 4% of the absorbed dose. The Dose Uniformity Ratio (DUR), between maximum and minimum dose levels in the canister, was in good agreement with the manufacturer specifications (≤1.5).


Subject(s)
Alanine , Radiation Dosimeters
5.
Nanoscale Adv ; 5(9): 2508-2516, 2023 May 02.
Article in English | MEDLINE | ID: mdl-37143794

ABSTRACT

Metal halide perovskites represent an intriguing class of materials, and a very promising approach to tune the properties of optoelectronic devices and improve their performance involves the implementation of architectures based on mixed 3D and 2D perovskites. In this work, we investigated the use of a corrugated 2D Dion-Jacobson perovskite as an additive to a classical 3D MAPbBr3 perovskite for applications in light-emitting diodes. Taking advantage of the properties of this emerging class of materials, we studied the effect of a 2D 2-(dimethylamino)ethylamine (DMEN)-based perovskite on the morphological, photophysical, and optoelectronic properties of 3D perovskite thin films. We used α-DMEN perovskite both in a mixture with MAPbBr3 creating mixed 2D/3D phases and as a passivating thin layer deposited on the top of a 3D perovskite polycrystalline film. We observed a beneficial modulation of the thin film surface, a blue shift in the emission spectrum, and enhanced device performance.

6.
Appl Radiat Isot ; 193: 110664, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36669267

ABSTRACT

The present study aims to evaluate the possibility of constructing a new high-speed railway (HSR) at Al Sadis Min Uktober city, Cairo (Egypt): geotechnical and environmental radiological hazards are estimated from several collected soil and water samples. A variety of laboratory geotechnical tests such as grain size, free swelling test, liquid and plastic limits, chemical analysis and uniaxial compression strength are applied to sixty-one drill holes. A geotechnical examination of the coarse-grained soil at the foundation level classified it as poorly graded soil. The results of the investigation of fine-grained soil at the foundation level shown that the liquid limit ranges from 22% to 55%, the plastic limit ranges from 12% to 28%, the plasticity index varies from 11% to 33%, free swelling varies from 51% to 71%. Mechanically, the uniaxial compressive strength values on rock samples range from 6.96 MPa to 142.39 MPa. The radioactive study is performed to detect the 226Ra, 232Th, and 40 K activity concentrations of the soil samples: their mean values are 34 ± 10 Bq·kg-1, 14 ± 5 Bq·kg-1 and 552 ± 20 Bq·kg-1, respectively. The values of radiological hazard indexes are not exceeded the permissible limits: e.g. the mean value of absorbed dose rate is 47 ± 6 nGy h-1; the annual gonadal dose equivalent is 0.3 ± 0.04 mSv·y-1; the lifetime cancer risk is 02 ± 0.2·10-3. Thus, the soil in the studied railway area is safe to use in building materials and infrastructure applications: the radiological hazards and the geotechnical studies confirmed the studied area is suitable to construct a new community having a HSR. According to the SWOT-PEST and environmental impact analyses, the construction of the HSR meets the criteria of the Kyoto Protocol, the EU Climate and Energy policy, and other international treaties.

7.
Appl Radiat Isot ; 185: 110221, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35427836

ABSTRACT

The possible damaging effects on human health of inhaled radon and its decay products are of interest to workers and the public. In particular, radon in thermal environments often occurs in high concentrations. Therefore, investigations and remedial actions are important to reduce activity concentration values and associated risk. This work concerns the analysis of two surveys of radon gas activity concentration carried out in 2006/2007 and 2019/2020 at twenty thermal spas on the island of Ischia (Italy). Annual measurements were carried out in workplaces located in the basement and ground floor using passive CR-39 detectors. In the spas involved in both surveys, the effectiveness of the remedial actions, implemented by the owners, was assessed obtaining an average percentage reduction of 74%. Considerations were made about the annual effective dose, and the location of the spas taking into account the geological setting of the volcanic nature of the island.


Subject(s)
Air Pollutants, Radioactive , Air Pollution, Indoor , Occupational Exposure , Radiation Monitoring , Radon , Air Pollutants, Radioactive/analysis , Air Pollution, Indoor/analysis , Humans , Italy , Occupational Exposure/analysis , Radiation Monitoring/methods , Radon/analysis
8.
Plant Dis ; : PDIS12212697PDN, 2022 Jun 20.
Article in English | MEDLINE | ID: mdl-35021870
9.
Biotechnol Biofuels ; 14(1): 182, 2021 Sep 16.
Article in English | MEDLINE | ID: mdl-34530890

ABSTRACT

BACKGROUND: Bio-hydrogen production via dark fermentation of low-value waste is a potent and simple mean of recovering energy, maximising the harvesting of reducing equivalents to produce the cleanest fuel amongst renewables. Following several position papers from companies and public bodies, the hydrogen economy is regaining interest, especially in combination with circular economy and the environmental benefits of short local supply chains, aiming at zero net emission of greenhouse gases (GHG). The biomasses attracting the largest interest are agricultural and urban green wastes (pruning of trees, collected leaves, grass clippings from public parks and boulevards), which are usually employed in compost production, with some concerns over the GHG emission during the process. Here, an alternative application of green wastes, low-value compost and intermediate products (partially composted but unsuitable for completing the process) is studied, pointing at the autochthonous microbial consortium as an already selected source of implementation for biomass degradation and hydrogen production. The biocatalysts investigated as mainly relevant for hydrogen production were the [FeFe]-hydrogenases expressed in Clostridia, given their very high turnover rates. RESULTS: Bio-hydrogen accumulation was related to the modulation of gene expression of multiple [FeFe]-hydrogenases from two strains (Clostridium beijerinckii AM2 and Clostridium tyrobutyricum AM6) isolated from the same waste. Reverse Transcriptase quantitative PCR (RT-qPCR) was applied over a period of 288 h and the RT-qPCR results showed that C. beijerinckii AM2 prevailed over C. tyrobutyricum AM6 and a high expression modulation of the 6 different [FeFe]-hydrogenase genes of C. beijerinckii in the first 23 h was observed, sustaining cumulative hydrogen production of 0.6 to 1.2 ml H2/g VS (volatile solids). These results are promising in terms of hydrogen yields, given that no pre-treatment was applied, and suggested a complex cellular regulation, linking the performance of dark fermentation with key functional genes involved in bio-H2 production in presence of the autochthonous consortium, with different roles, time, and mode of expression of the involved hydrogenases. CONCLUSIONS: An applicative outcome of the hydrogenases genes quantitative expression analysis can be foreseen in optimising (on the basis of the acquired functional data) hydrogen production from a nutrient-poor green waste and/or low added value compost, in a perspective of circular bioeconomy.

10.
Syst Rev ; 10(1): 148, 2021 05 12.
Article in English | MEDLINE | ID: mdl-33980324

ABSTRACT

BACKGROUND: Venous leg ulcers (VLUs) are chronic wounds characterized by slow healing and high recurrence. Information on prevalence and incidence is essential for ascertaining the burden of VLU on the health care system and to inform epidemiological research, priority setting, and health care planning. The objective of this protocol is to present a transparent process for how we plan to review the existing international literature on the prevalence and incidence of VLU as well as the characteristics of the population reported within these studies. METHODS: An exploratory search was performed using MEDLINE via PubMed and CINHAL via Ebsco to identify concepts, keywords, MeSH terms, and headings to identify study types looking at data of VLU prevalence and/or incidence and related patient characteristics. The findings of this exploratory search will determine the final search strategy. The titles and abstracts of the identified articles will be screened independently be two authors for relevance. Study which pass the quality assessment will be included. Data extraction will be performed independently by two authors and in accordance with a pre-designed data extraction form. If the data allows, a meta-analysis will be performed otherwise a descriptive summary of the findings will be conducted. DISCUSSION: The results of this review will contribute to the evidence base on VLU occurrence and may inform the decision making of healthcare professionals, policy-makers, and consumers. It will also inform future research in this area of VLU care. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020205855.


Subject(s)
Varicose Ulcer , Epidemiologic Studies , Humans , Incidence , Meta-Analysis as Topic , Prevalence , Systematic Reviews as Topic , Varicose Ulcer/epidemiology , Wound Healing
11.
Sci Rep ; 10(1): 9551, 2020 06 12.
Article in English | MEDLINE | ID: mdl-32533027

ABSTRACT

This is a seven-year study (1/7/2011-31/12/2017) of radon monitoring at two sites of Campi Flegrei caldera (Neaples, Southern Italy) that in the last 70 years experienced repeated phases of volcanic unrest. The sites are equipped with devices for radon detection, based on the spectrometry analysis of the α-particles of radon daughters. A hybrid method, as combination of three known methods, is applied for the identification of residuals (anomalies) and trends of the time series of Radon. The results are compared with the following indicators of current caldera unrest: the tremor caused by the major fumarolic vent registered by a seismic station; the cumulative of background seismicity; the maximum vertical deformation acquired by GPS networks during the current phase of uplift; the temperature-pressure of the hydrothermal system estimated based on gas geo-indicators. The comparisons show strong correlation among independent signals and suggest that the extension of the area affected by current Campi Flegrei crisis is larger than the area of seismicity and of intense hydrothermal activity from which the radon stations are 1-4 km away. These results represent an absolute novelty in the study of a such calderic area and mark a significant step forward in the use and interpretation of the radon signal.

12.
Oncol Rep ; 43(6): 1729-1736, 2020 06.
Article in English | MEDLINE | ID: mdl-32236596

ABSTRACT

Protease inhibitors (PIs) inhibit HIV­1 and HIV­2 proteases, impeding virus replication and liberation of viral elements from infected cells. In human immunodeficiency virus (HIV) subjects receiving PI­based treatment, an impressive decrease in the amount of HIV­associated cancers, unconnected to viral burden or CD4 amount was observed. Research has reported that PIs have influence on cancer proliferation, spread, and survival as an effect on endoplasmic reticulum stress, proteasome, NF­κB and Akt signalling. Nelfinavir (NFV) is a nonpeptidic PI that functions by connecting to the catalytic site of the HIV protease, thus stopping the cleavage of viral polyprotein into complete, operative proteins that are fundamental for viral survival. NFV, currently not frequently employed for antiretroviral treatment, has demonstrated noteworthy off target effects in tumor patients with or without HIV disease. NFV appears to cause cell death in tumor cells by different mechanisms, which include necrosis, apoptosis and autophagy. In this review, data from preclinical research and clinical trials are reported and the mechanisms of action of NFV and their results in the treatment of hematologic malignancies, such as acute myeloid leukemia, chronic lymphoid leukemia, and diffuse large B cell lymphoma, and especially in patients with multiple myeloma are examined. In the future, experimental studies may help identify the role of NFV in cancer treatment and may promote the application of this drug into daily clinical practice.


Subject(s)
Antineoplastic Agents/therapeutic use , Hematologic Neoplasms/drug therapy , Multiple Myeloma/drug therapy , Nelfinavir/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Cell Proliferation/drug effects , Cell Survival/drug effects , Clinical Trials as Topic , Drug Repositioning , Humans , Nelfinavir/pharmacology
14.
Radiat Environ Biophys ; 58(4): 575-583, 2019 11.
Article in English | MEDLINE | ID: mdl-31463523

ABSTRACT

Phaseolus vulgaris L. plants were irradiated with different doses (0.3, 10, 50 and 100 Gy) of X-rays in order to obtain a reference curve of response to ionizing radiations for this species. Growth analysis, gas exchange and chlorophyll a fluorescence measurements were performed to estimate the radio-resistance of bean plants. Specifically, there was a negative influence of X-rays on the net photosynthesis rate at 50 and 100 Gy, already on the day of irradiation. Experimental data showed a recovery over time in the gas exchange while the theoretical maximum photochemical efficiency of the photosystem II (Fv/Fm) was fairly constant throughout the period of measurements (20 days) and for all the experimental conditions. On the other hand, the quantum yield of PSII linear electron transport (ΦPSII) and non-photochemical quenching (NPQ) were deeply influenced over time by X-ray dose, suggesting a decrease in the functionality of the photosynthetic apparatus at the highest radiation doses. The growth was affected only at the highest doses of radiation with a significant and severe reduction of leaf expansion and number of leaves per plant. Despite the arrest in growth, X-ray exposure seems to trigger an increased photochemical activity probably signifying that P. vulgaris plants have a fairly elevated resistance to this kind of ionizing radiation. Our current results will provide a complete analysis of the photosystem II (PSII) response of P. vulgaris to different doses (0.3, 10, 50 and 100 Gy) of X-rays, providing sound references for both space-oriented and radioecology questions.


Subject(s)
Chlorophyll A/metabolism , Phaseolus/radiation effects , Photosynthesis/radiation effects , Fluorescence , Phaseolus/physiology , Plant Leaves , Radiation, Ionizing , Radiography , X-Rays
15.
Sci Adv ; 5(5): eaav9967, 2019 May.
Article in English | MEDLINE | ID: mdl-31172027

ABSTRACT

Polaritonic devices exploit the coherent coupling between excitonic and photonic degrees of freedom to perform highly nonlinear operations with low input powers. Most of the current results exploit excitons in epitaxially grown quantum wells and require low-temperature operation, while viable alternatives have yet to be found at room temperature. We show that large single-crystal flakes of two-dimensional layered perovskite are able to sustain strong polariton nonlinearities at room temperature without the need to be embedded in an optical cavity formed by highly reflecting mirrors. In particular, exciton-exciton interaction energies are shown to be spin dependent, remarkably similar to the ones known for inorganic quantum wells at cryogenic temperatures, and more than one order of magnitude larger than alternative room temperature polariton devices reported so far. Because of their easy fabrication, large dipolar oscillator strengths, and strong nonlinearities, these materials pave the way for realization of polariton devices at room temperature.

16.
Neth J Med ; 77(2): 67-80, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30895929

ABSTRACT

Human beings are inhabited by innumerable microorganisms that interrelate with the host in a reciprocal way, establishing a combined and efficient ecosystem - the microbiota - that can affect healthiness as well as disease. There is evidence that the conformation of the microbiota may influence, and is controlled by, the human immune system. Microbes existing in human tissues offer a multiplicity of advantages that participate in functional actions in the host through the adjustment of essential processes such as immunity, signal transduction, and metabolism. The imbalance of this microbial structure has been connected with the pathogenesis and progression of cancer. We reviewed the present knowledge of the diverse microbial ecosystems and we investigated their potential link to carcinogenesis, and the possibility of using advantageous microbes in controlling and preventing hematologic malignancies.


Subject(s)
Hematologic Neoplasms/microbiology , Microbiota , Antineoplastic Agents/adverse effects , Antineoplastic Agents/therapeutic use , Hematologic Neoplasms/drug therapy , Humans , Microbiota/genetics , Prebiotics/administration & dosage , Probiotics/pharmacology
17.
Radiat Prot Dosimetry ; 183(1-2): 116-120, 2019 May 01.
Article in English | MEDLINE | ID: mdl-30668835

ABSTRACT

The mechanobiology is providing novel perspectives in the study of cancer and is contributing to evaluate the cancer responses, from a biophysical point of view, to classical therapeutic approaches- radiotherapy and chemotherapy. Here we have explored the effects of two doses (4 and 8 Gy) of 6 MeV photons on spreading, focal adhesions, migration and mechanical properties of BALB/c 3T3 and their SV40 transformed equivalent, SVT2. Cell biophysical responses to 4 and 8 Gy were analysed and compared with those reported in previous published work when lower doses (1 and 2 Gy) were administered Panzetta et al. (Effects of high energy X-rays on cell morphology and functions. Proc. Book 2017;16:116). We observed that the range of sensitivity to ionising radiations profoundly changes depending on the patho-physiological state of cells. In particular, we found that X-rays induce morphological and functional variations in both cell lines (decreased motility, increased adhesion and increased cytoskeleton stiffness). These changes were slightly dependent on doses in the case of SVT2 cells and may indicate a possible mechanical normalisation in their phenotype. Nevertheless, the responses of BALB/c 3T3 were negligible only for the low dose of 1 Gy and increased significantly in a dose-dependent manner with higher doses. We believe that the characterisation of X-rays effects on the cell mechanobiology could shed new light in the design and customisation of radiotherapy treatments.


Subject(s)
Biophysics/methods , Cells, Cultured/radiation effects , Cell Line , Cytoskeleton/radiation effects , Dose-Response Relationship, Radiation , Photons , Relative Biological Effectiveness , X-Rays
18.
J Appl Microbiol ; 126(3): 905-918, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30417496

ABSTRACT

AIMS: The response of rhizosphere and bulk soil indigenous microbial communities focusing on nitrifiers was evaluated after the application of different biological control agents (BCAs; Bacillus, Trichoderma, Pseudomonas) and compost in controlling lettuce Fusarium wilt. METHODS AND RESULTS: Experiments were conducted 'in situ' over two lettuce cropping seasons. Total fungal, bacterial and archaeal populations and the nitrifiers were analysed using quantitative polymerase chain reaction method. The pathogen, Fusarium oxysporum forma specialis lactucae (FOL), Bacillus, Trichoderma and Pseudomonas and three antifungal genes (chiA, 2,4-diacetylphloroglucinol - phlD and HCN synthase - hcnAB genes) were also assessed. Quantitative data were corroborated with disease severity (DS), potential nitrification activity and soil chemical parameters. The application of BCAs and compost resulted in the disease reduction by as much as 69%, confirmed by significant negative correlations between Bacillus subtilis, Trichoderma and Pseudomonas sp. abundances and DS. The FOL presence in the untreated control resulted in the nitrifiers niche differentiation. CONCLUSIONS: The used treatments were efficient against Fusarium wilt and did not influence negatively the nontarget microbial communities. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of BCAs and compost appears as an effective and safe strategy to implement sustainable agricultural practices.


Subject(s)
Biological Control Agents , Fusarium , Lactuca/microbiology , Microbiota/physiology , Rhizosphere , Soil Microbiology , Fusarium/metabolism , Fusarium/physiology , Nitrification
19.
Radiat Prot Dosimetry ; 177(1-2): 202-206, 2017 Nov 01.
Article in English | MEDLINE | ID: mdl-29036347

ABSTRACT

This work concerns continuous monitoring of radon and thoron specific activity in soil gas within the framework of identifying possible anomalies. It is based on the analysis of a medium-term data record obtained from soil gas in an area of geophysical interest. The RaMonA spectrometric system is also used to measure the climatic parameters and a specific analysis of the alpha spectra is performed to better determine the alpha lines intensity. Since radon emission is also influenced by meteorological parameters, it is mandatory to differentiate the changes due to the deep phenomena. Different procedures are utilized to reach the above objective: statistical analysis using the Empirical Mode Decomposition technique, the Multiple Linear Regression method and the Remote Radon Estimation by using of the thoron trend to eliminate the locally produced radon fraction. The results of such methods are compared to recognize and to highlight radon anomalies.


Subject(s)
Radiation Monitoring/methods , Radon/analysis , Soil Pollutants, Radioactive/analysis , Interrupted Time Series Analysis , Italy , Radiation Monitoring/instrumentation , Seasons , Weather
20.
J Environ Radioact ; 172: 201-206, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28390309

ABSTRACT

It has been widely shown that nuclear fallout includes substances, which accumulate in organisms such as crustaceans, fish, mushrooms and lichens, helping to evaluate the activity concentration of contaminants accumulated on a long time. In this context, radiocaesium deposited in soil following the Chernobyl accident on 26 April 1986 is known to have remained persistently available for plant uptake in many areas of Europe. Studies on the lichen Stereocaulon vesuvianum show the plant's high capacity to retain radionuclides from the substrate and the air. After the Chernobyl accident, starting from September 1986, at the Radioactivity Laboratory (LaRa) of the University of Naples Federico II, four monitoring campaigns to evaluate the activity concentration of four isotopes of the two elements caesium and ruthenium (134Cs, 137Cs, 103Ru and 106Ru) were carried out until 1999. This study allowed the effective half-life of 134Cs and 137Cs to be estimated. Twenty-eight years after the accident, in December 2014, a further sampling was carried out; only 137Cs was revealed beyond the detection limits, measuring activity concentrations ranging from 20 to 40 Bq/kg, while the other radionuclides were no longer observed due to their shorter half-life. The last sampling allowed more precise determination of the effective half-life of 137Cs (6.2 ± 0.1 year), due to the larger dataset on a large time period.


Subject(s)
Air Pollutants, Radioactive/analysis , Cesium Radioisotopes/analysis , Chernobyl Nuclear Accident , Lichens/chemistry , Radiation Monitoring , Radioactive Fallout/analysis , Radioactivity
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