Radioactive Particles Research Articles

Impact of column geometry and internals on gas and particle flows in a fluidized bed with downward solids circulation: Effect of lateral injection profile and baffles

This paper investigates how solids flow in a circulating fluidized bed can be modified by adding baffles and modifying gas injection locations, and how these changes suggest strategies for a reduction of liquid carryunder in the stripper in Fluid Cokers™. A Computer-Aided Radioactive Particle Tracking (CARPT) method was used with a pilot unit operated at room temperature with the same flux of recirculating coke particles as in the commercial unit. The lateral bitumen injections, and their impact on superficial gas velocity were simulated with 5 banks of 8 lateral gas injectors. In cokers, wet agglomerates that trapped injected bitumen carry unreacted liquid to the stripper. Radioactive simulated agglomerates were tracked to obtain formation-to-stripper time distribution profiles, for each lateral injection jet. Two methods were investigated to reduce liquid carryunder: the addition of a ring baffle and redistribution of liquid between banks. Experiments showed that carryunder can be reduced by either redirecting the bitumen feed from the lowest injection bank to higher banks, or adding a ring baffle with flux tubes in between the lowest and second-lowest injection banks. Combining both methods does not provide additional improvement.

Mycoremediation affects antioxidative status in winter rye plants grown at Chernobyl exclusion zone site in Ukraine.

Soil contaminated with heavy metals in general and radionuclides in particular represents an escalating problem for all living organisms. Since, Chernobyl nuclear power plant accident in 1986 in Ukraine, an exclusion zone of 30 km around the former power plant is uninhabitable land due to severe contamination. Two most notable beta emitters contributing to dose hazards for decades is radioactive 137Cs/90Sr. However, large parts of the zone are also highly contaminated with uranium particles (hot particles) bearing trace amounts of highly alpha-emitting radionuclides. We established an experiment at exclusion zone with the aim to investigate the influence of two macro fungi (Schizophyllum commune (S.C.) and Leucoagaricus naucinus (L.N.)) on oxidative status and antioxidative responses in winter rye plants; from this, we wanted to test the radionuclide/heavy metals retention capacity of both fungi, and probe their further potential for mycoremediation.Result shows some differences in the concentrations of radionuclides/heavy metals and micro/macronutrients uptake in plants. As a biomarker of oxidative status, lipid peroxidation (LPO) levels and other antioxidative parameters were determined, i.e., superoxide-dismutase (SOD) isoenzymes, cysteine (CYS), and ascorbic acid (AA) concentrations as well as catalase (CAT) and glutathione reductase (GR) activities in winter rye shoots. LPO showed no significant differences between controls and plants cultivated with macro fungi. However, CAT activities were elevated in the presence of S.C/L.N compared with control, while GR activity was significantly higher only in presence of S.C. In contrast, isozyme of SOD (Cu,Zn-SOD) was the most prominent in control. Likewise, CYS content was lower in plants grown with both fungi, while AA concentration was only lower in the presence of L.N. The results showed that presence of fungi in radionuclide contaminated soil caused induction of antioxidative response in shoots of winter rye and that the response depended on the type of fungi used.

Insights on the role of primary and secondary tar reactions in soot inception during fast pyrolysis of coal

In the present work fast pyrolysis of coal in N2 and CO2 atmospheres was studied in a drop tube reactor (DTR) and in a heated strip reactor (HSR). In the DTR the volatiles generated by coal pyrolysis were entrained in a hot gas stream and were collected at the reactor outlet by tar traps. In the HSR, the volatiles were ejected from the hot coal particles into a cool environment and the condensable species, including primary tar, deposited and/or condensed on a glass bridge located above the heated strip. The composition of tars produced in the two reactors was compared to study the role of gas tar reactions in soot inception, and reference compounds for each class of tar species produced were identified.In the DTR the formation and growth of polycyclic aromatic hydrocarbons (PAH) were found higher than in the HSR. Soot formation occurred only in the DTR, being negligible in the HSR.It was concluded that the hot gas environment of the DTR favours secondary tar reactions, formation of PAH and eventually soot, while in the HSR this path was prevented due to prompt cooling down of volatiles. The presence of large concentration of CO2 in the pyrolysis atmospheres further promoted formation of heavy PAH and soot in the DTR, but not in the HSR, where the cooler environment limits soot-CO2 reactions in the gas phase.

Ambient particle radioactivity and gestational diabetes: A cohort study of more than 1 million pregnant women in Massachusetts, USA

BackgroundExposure to ionizing radiation increases the risk of chronic metabolic disorders such as insulin resistance and type 2 diabetes. Internal ionizing radiation from inhaled radioactive aerosol may contribute to the associations between fine particulate matter (PM2.5) and gestational diabetes mellitus (GDM). MethodsWe used the Massachusetts Registry of Vital Records to study 1,061,937 pregnant women from 2001 to 2015 with a singleton pregnancy without pre-existing diabetes. Gross β activity measured by seven monitors of the U.S. Environmental Protection Agency's RadNet monitoring network was utilized to represent ambient particle radioactivity (PR). We obtained GDM status from birth certificates and used logistic regression analyses adjusted for socio-demographics, maternal comorbidities, PM2.5, temperature and relative humidity. We also examined effect modification by smoking habits. ResultsAmbient particle radioactivity exposure during first and second trimester of pregnancy was associated with higher odds of GDM (OR: 1.18 (95% CI 1.10 to 1.22). Controlling for PM2.5 did not substantially change the effects of PR on GDM. In women that reported being former or current smokers, the association between PR and GDM was null. In the full cohort, the overall effect of PM2.5 on GDM without adjusting for PR was not significant. ConclusionThis is the first population-based study to examine the association between particle radioactivity and gestational diabetes mellitus - one of the most common pregnancy-related diseases with lifelong effects for the mother and the fetus. This finding has important public health policy implications because it enhances our understanding about the toxicity of PR, a modifiable risk factor, which to date, has been considered only as an indoor and occupational air quality risk.

Exposure to Particle Beta Radiation in Greater Massachusetts and Factors Influencing Its Spatial and Temporal Variability

Particle radioactivity is a property of airborne particles caused by the presence of naturally occurring or anthropogenic radionuclides. Recent studies have found associations between particle radioactivity and adverse health outcomes, including changes in blood pressure and lung function. However, the spatiotemporal distribution of particle radioactivity and factors influencing its variability have not been extensively studied. We address these knowledge gaps using measurements of gross beta activity, collected at seven Environmental Protection Agency (EPA) RadNet monitors located in and around Massachusetts. We apply back-trajectory analysis to identify prevailing air mass trajectories and find that these trajectories strongly influence seasonal trends in beta activity. We also evaluate the effects of different meteorological predictors on daily beta activity concentrations using a mixed-effect model. Important predictors of beta activity include air mass trajectories, temperature, and relative humidity. Finally, we create a series of random forest models to impute missing beta activity concentrations at each RadNet monitor for use in future health studies. This is the first study to analyze spatiotemporal trends in particle radioactivity using measurements from the EPA RadNet system.

Development of structural optimization design method for multilayer metal fiber filter in nuclear power plant

The metal fiber filter as one of the most efficient gas cleaning medium presents potential application prospect to remove the radioactive particles and droplet from gaseous during severe accident in nuclear power plant. In this paper, the filtration performance of single layer metal fiber with different fiber diameters is studied in condition of U = 0.25 m/s, and an optimization method for multilayer filter design is developed based on single layer results. It indicates that the metal fiber filter with smaller fiber diameters presents higher filtration efficiency, especially for small size aerosols, but will also lead to a greater flow resistance. A multilayer metal fiber filter with 20-layers is finally selected by taking into consideration of efficiency, resistance and economy comprehensively. The filtration efficiency of this optimized filter under MPPS is verified 99.91%, which indicating that the optimized combination scheme meets the requirements and also the optimization method developed in this paper is reasonable and feasible.

Study of particulate matters concentration and radiation rate in the atmosphere of Ilam city during middle east dust storms

ABSTRACTThe possibility of suspending radioactive particles during dust storms from Iraq and entering Iran has always been a concern. The aim of this study was to investigate the particulate matter concentration during dusty days and the effect of dust storm on the irradiation rate in the atmosphere of the city of Ilam (capital of Ilam province). The concentration of particulate matter and radiation dose in the study area were monitored between March 2012 and February 2013 (1 year). Sampling was done every 6 days for periodical days. For the dusty days, samples were gathered according to the forecast information of dust plum entrance by the meteorological organisation. The results showed that the average and standard deviation of PM10, PM2.5, and PM1 concentrations in the periodic sampling (every 6 days) were 76.9 ± 57.1, 17.5 ± 10.5, and 8 ± 4 μg/m3, respectively, and in the dusty days were286 ± 164.8, 54.4 ± 30.3, and 14.6 ± 6.5 μg/m3, respectively. During the study period, the concentration of PM10in 35 days were more than 150 μg/m3 (Dusty day), and June with 13 days was the highest number dusty days. The average radiation dose in normal and dusty days were 0.152 and 0.150 μSv/hr, respectively. The results of Mann–Whitney’s test showed that there was no significant difference between measured radiation in normal and dusty days (P > 0.05). Spearman test showed that there was no significant correlation between radiation doses and PM (PM10, PM2.5, and PM1) (P > 0.05). The results of the study show that dust storms and its concentration intensity did not affect the amount of radiation in the Ilam atmosphere. Because of the high density of the uranium element and its rapid sedimentation near the emission sources, the entry of this contamination related to dust storms to Ilam has not been proven.

Experimental and numerical investigation of pumping ventilation on the leeward side of a cubic building

Unstable interaction between shear layers that form in the wake of an isolated building exposed to wind can drive natural pumping ventilation in windward and leeward facing rooms with two or more horizontally separated openings. This paper presents an experimental and numerical study of pumping ventilation in a three-story cubic building with two leeward openings in its middle floor. Reduced-scaled measurements were performed in the University of Gävle atmospheric-boundary-layer wind tunnel. The ventilation mechanism was investigated using smoke visualization, hot wire anemometry and particle image velocimetry. Effective ventilation rates were obtained using a tracer gas decay method.Experimental results confirmed that pumping ventilation is a 3D oscillatory unstable phenomenon with periodic behavior over several oscillation cycles. Measured flowrates show a linear relation between the effective ventilation rate and window separation. The numerical simulations used two turbulence modeling approaches: unsteady Reynolds-averaged Navier-Stokes (URANS) and large eddy simulation (LES). Both URANS and LES could predict vortex shedding frequency with an error below 5%. LES showed a good agreement with the measured ventilation rates, with an error below 10%, while URANS underestimated ventilation rates by at least 40%. The ventilation efficiency, obtained by LES, ranged between 0.60 and 0.75 (for the case with larger window separation). The results show that LES may be a suitable simulation approach for pumping ventilation. In contrast, URANS cannot simulate pumping ventilation.

Possibility of estimating radioactive fallout by modelling atmospheric processes

The paper suggests methods and means for solving problems of determining contamination by radioactive waste, appearing as precipitation when moving radioactive particles in the atmosphere.

Association between ambient beta particle radioactivity and lower hemoglobin concentrations in a cohort of elderly men

Although ionizing radiation is known to have detrimental effects on red blood cells, the effect of environmental radioactivity associated with ambient particulate matter (PM) is unknown. We hypothesized that exposure to ambient PM-associated beta particle radioactivity (PRβ) would be associated with a lower hemoglobin concentration. We studied 1.704 participants from the Normative Aging Study (NAS) over 36 years (1981–2017) who lived in Eastern, MA and the surrounding area. Exposures to PRβ was assessed using USEPA’s RadNet monitoring network that measures gross beta radiation associated with ambient PM. Mixed effect models with a random intercept adjusting for potential confounders was used, including ambient black carbon (BC) and particulate matter ≤2.5 μm (PM2.5) concentrations. Greater cumulative PRβ activities at 7-, 14-, 21- and 28-days before the hemoglobin determination were associated with lower hemoglobin concentrations. The greatest effect was for a 28-day moving average. An IQR of 0.83 × 10−4 Bq/m3 of ambient PRβ was associated with a 0.12 g/dL decrease in hemoglobin concentration (95%CI: −0.18 to −0.05). The effects of PRβ were similar when the models were adjusted for ambient BC or PM2.5. This is the first study to demonstrate an association between environmental ionizing radiation released from particulate matter with a lower hemoglobin concentration, suggesting that ambient radiation may contribute to the development of anemia.

Heat transfer in a pulsating turbulent fluidized bed

The multiphase Eulerian-Eulerian approach was applied to investigate heat transfer through an immersed tube in a turbulent fluidized bed computationally. Heat transfer occurred in the turbulent fluidized bed via four mechanisms: particle-tube conduction, particle-particle conduction, gas-tube convection and gas-particle convection. A strong correlation between heat transfer performance and particle distribution around the immersed tube was observed. Replacement of hot particles around the tube with cold particles promoted heat transfer. Three parametric studies on effects of fluidization regime, particle size and pulsed flow were conducted. It was observed that the heat transfer performance of a bubbling fluidized bed was superior to that of a turbulent fluidized bed. The size of gas pocket increased with increasing particle size. As the tube was enveloped by gas pockets for a longer period of time, particle-tube conduction was hindered and average heat transfer coefficient around the tube decreased. Two key weaknesses of a turbulent fluidized bed were identified to be formation of large gas pockets and presence of a stagnant zone above the tube. The novelty of the current study is the application of pulsed flow to address these weaknesses. It was observed that there existed an optimal pulsating frequency at which heat transfer in a turbulent fluidized bed was enhanced. When the pulsating amplitude was selected such that the fluidized bed oscillated between two different fluidization regimes, the heat transfer performance of the turbulent fluidized bed became comparable to that of a bubbling fluidized bed.

A model to determine the overall bed-to-wall heat transfer coefficient and its influence factor analysis in moving bed

Waste heat recovery of hot particles based on the moving bed is recognized widely in the industrial applications. However, the heat transfer process in the moving bed is complicated and there is still a lack of effective heat transfer model to predict accurately the heat transfer behavior of moving bed. In this paper, a heat transfer model is developed to calculate the overall bed-to-wall heat transfer coefficient of moving bed containing randomly packed mono-sized spherical particles. In this model, the radiation and the conduction are the main modes of heat transfer. Due to the downward movement of particles in the moving bed, the convection between the particles and the gas is indispensable for this model (only convection caused by particle movement is considered in this paper). And the convection is incorporated in the particle internal conduction as boundary condition. By comparing with the experimental data, it is verified that this model can predict effectively the overall bed-to-wall heat transfer coefficient of moving bed under various working conditions. The effects of parameters such as the particle temperature, the particle size and the particle descending speed on the heat transfer coefficient are also taken into account. Especially, the particle descending speed has a crucial influence on the heat transfer behavior of moving bed, which has been studied rarely in previous researches. The results show that the increase of particle descending speed has a positive effect on the heat transfer of moving bed, which contributes to the industrial design of waste heat recovery of hot particles.

Characterization of radioactive particles from the Dounreay nuclear reprocessing facility

Radioactive particles originating from nuclear fuel reprocessing at the United Kingdom Atomic Energy Authority's Dounreay Facility were inadvertently released to the environment in the late 1950s to 1970s and have subsequently been found on site grounds and local beaches. Previous assessments of risk associated with encountering a particle have been based on conservative assumptions related to particle composition and speciation. To reduce uncertainties associated with environmental impact assessments from Dounreay particles, further characterization is relevant.Results of particles available for this study showed variation between Dounreay Fast Reactor (DFR) and Materials Test Reactor (MTR) particles, reflecting differences in fuel design, release scenarios, and subsequent environmental influence. Analyses of DFR particles showed they are small (100–300 μm) and contain spatially correlated U and Nb. Molybdenum, part of the DFR fuel, was identified at atomic concentrations below 1%. Based on SR-based micrometer-scale X-ray Absorption Near Edge Structure spectroscopy (μ-XANES), U may be present as U(IV), and, based on a measured Nb/U atom ratio of ~2, stoichiometric considerations are commensurable with the presence of UNb2O7. The MTR particles were larger (740–2000 μm) and contained U and Al inhomogeneously distributed. Neodymium (Nd) was identified in atomic concentrations of around 1–2%, suggesting it was part of the fuel design. The presence of U(IV) in MTR particles, as indicated by μ-XANES analysis, may be related to oxidation of particle surfaces, as could be expected due to corrosion of UAlx fuel particles in air. High 235U/238U atom ratios in individual DFR (3.2 ± 0.8) and MTR (2.6 ± 0.4) particles reflected the presence of highly enriched uranium. The DFR particles featured lower 137Cs activity levels (2.00–9.58 kBq/particle) than the MTR (43.2–641 kBq 137Cs/particle) particles. The activities of the dose contributing radionuclides 90Sr/90Y were proportional to 137Cs (90Sr/137Cs activity ratio ≈ 0.8) and particle activities were roughly proportional to the size. Based on direct beta measurements, gamma spectrometry, and the VARSKIN6 model, contact dose rates were calculated to be approximately 74 mGy/h for the highest activity MTR particle, in agreement with previously published estimates.

Heat transfer in a pulsed fluidized bed by using coupled CFD-DEM method

Heat transfer behaviors in a pulsed fluidized bed are numerically investigated by means of a combined approach of computational fluid dynamics (CFD) and discrete element method (DEM). The effect of pulsation flow on bed heat transfer characteristics is evaluated. It is found that the pulsed gas flow leads to an intense oscillating flow behavior in the bed, enhancing the the cooling rate of hot particles. Three kinds of heat transfer mechanisms are examined. The results reveal that the particle-fluid convection is dominated. Meanwhile, heat transfer mechanisms in a polydisperse system are also discussed. It is observed that the addition of fine particles promotes the total particle-fluid convection and the fluctuating degree with time becomes evident.

The Predictors of Peri-Procedural and Sub-Acute Cerebrovascular Events Following TAVR

In Brazil, concrete and cement are highly used in construction, therefore mixers are widely used in this industry. During the fabrication process of concrete/cement, the equipment may fail and compromise the appropriate mixing procedure. Besides that, it is also important to determine the right point of homogeneity of the mixture. It is important to have a methodology to monitor the mixing process to ensure the quality of the product. This study presents a methodology based on the principles of the radioactive particle tracking technique to predict the instantaneous positions occupied by the radioactive particle inside an industrial mixer by means of a mathematical location algorithm. The detection geometry modeled by means of MCNPX code employs an array of eight NaI(Tl) scintillator detectors, a 198Au spherical gamma-rays source with isotropic emission and a test section filled with concrete that represents an industrial mixer. The choice of the radionuclide is due its well-characterized peak of 411 keV, its half-life of 2.7 days and the possibility to obtain 198Au by neutron activation in reactors. The purpose of this study is to use an artificial neural network as a location algorithm of the 198Au radioactive particle inside an industrial mixer. Results showed that over 56% of the cases were below 5% of relative error for all coordinates of the radioactive particle, which indicates that it is possible to track the radioactive particle trajectory inside the industrial mixer using the artificial neural network algorithm.

A critical review on microwave, fluidised-bed and convective air-drying of low rank coals: The water diffusivity on coals

A critical review on drying of low rank coal drying using conventional air-drying, fluidised bed drying and microwave drying methods. The parameters of different drying methods that affected the water effective diffusivity values were identified and critically discussed in details including hot air temperatures, flow rates, particle sizes, particle weights, and microwave powers. The microwave and fluidised bed drying methods are more effective in drying of low rank coal compared to the conventional hot air drying method. This is because the microwave drying method can heat up the internal part of the coal, thus leads to a higher drying rate and effective diffusivity values whereas the fluidised bed causes an uniform distribution of heating medium to heat up the low rank coal and the fluidisation resulted in a better mixing performance and a higher heat and mass transfer compared to the conventional hot air drying. Moreover, Midilli-Kucuk model was the best and most commonly used drying model for drying of the low rank coal. In the fluidised bed drying, the Midilli-Kucuk was the best-fitted drying model to dry the low rank coal whereas Wang & Singh model was the best drying model in the fixed-bed drying for the coarse particle of low rank coal. The microwave drying kinetics can be modeled using either the Page Model or Midilli-Kucuk model. Further to this, it was found that few parameters that significantly affected the effective diffusivity of the low rank coal are increasing temperature and flow rates of the convective air-drying meanwhile increasing the particle size and particle weight results in a decrease in effective diffusivity value for the fluidized-bed drying.

Dysfunctional Natural Killer cells expanded from a liver with Hepatocellular Carcinoma show reduced killing against a unique HCC cell line

BackgroundThe liver has one of the largest reserves of NK cells in the body. NK cells in the liver are key defenses against viral hepatitis, liver fibrosis, and tumorigenesis. In the healthy liver, they exhibit higher cytotoxicity and secrete more cytokines compared to those isolated from peripheral blood. Hepatocellular carcinoma (HCC) is one of the most rapidly increasing cancers worldwide. Previously, NK cells have been shown to be dysfunctional in HCC. Additionally, NK cells are reduced in number intratumorally and peripherally and there is a decrease in the cytotoxic CD56dim subpopulation. Many studies have shown a downregulation of key signaling molecules involved in peripheral NK cell cytotoxic activity. We aimed to further investigate the level of dysfunction of NK cells isolated from HCC livers to document the nature of dysfunction of liver‐resident NK cells in eliminating HCC cell lines.MethodsBriefly, samples of tissue were collected from explanted livers and made into single cell suspensions. Next, lymphocytes were isolated using density‐based centrifugation. The resulting fraction was placed into RPMI‐1640 with IL‐2 and IL‐15. After two weeks, samples were taken to determine the number and purity of NK cells by flow cytometry. Target cell lines were labeled with chromium‐51 to test the killing capacities of NK cells isolated from healthy donor PBMC’s or HCC patient livers. NK cells were prepared in serial dilutions and in triplicate to generate a killing curve. After 4 hours of coincubation of effector NK cells with target cells, the released radioactive particles were measured and analyzed.ResultsTwo cell lines, Hep3B (ATCC) and HCO2 (generated in our lab), were used as target cells. Figures 1 and 2 depict the results of separate killing assays using the different target HCC cell lines. The effector cells in each assay consist of NK cells sourced from either healthy donor PBMC’s, cirrhotic patient PBMC’s, or HCC liver. Notably, the results show that even under the constant stimulation of IL‐2 and IL‐15, which are known interleukins that are involved in the proliferation and activation of NK cells and T‐cells, there is a large dysfunction in NK cells sourced from diseased livers. More strikingly, our results show that there is a specific inability of NK cells sourced from HCC livers to eliminate HCO2 cells which have been previously shown in our lab to be sorafenib‐resistant. Our hypothesis is that there is an innate dysfunction that is present in NK cells isolated from diseased livers that is not recoverable even when cultured in the presence of activating cytokines. Additionally, HCO2 cells possess a unique resistance to killing by NK cells isolated and expanded from an HCC liver.ConclusionHere we show that NK cells can be isolated and expanded, ex vivo, from human diseased livers. Additionally, we show that despite being stimulated for over 2 weeks with cytokines, expanded NK cells still show a marked reduction in killing capacity against a variety of HCC cell lines compared to NK cells expanded from PBMC’s from healthy and diseased donors. Our results confirm that there is an innate dysfunction that is present within NK cells isolated from diseased livers that is not recoverable even when cultured in the presence of activating cytokines.HCC cell lines (Hep3B, in circles, HCO2, in triangles) were labeled with Chromium‐51 for 2 hours. Target cells were rinsed with media and cocultured with NK cells at various effector‐to‐target ratios. NK cells were sourced from either PBMC’s from a cirrhotic patient (PBNK, in blue) or a liver with hepatocellular carcinoma (LNK, in green) and expanded ex vivo with IL‐2 and IL‐15.Figure 1

The Role of Ambient Particle Radioactivity in Inflammation and Endothelial Function in an Elderly Cohort.

The mechanisms by which exposure to particulate matter might increase risk of cardiovascular morbidity and mortality are not fully known. However, few existing studies have investigated the potential role of particle radioactivity. Naturally occurring radionuclides attach to particulate matter and continue to release ionizing radiation after inhalation and deposition in the lungs. We hypothesize that exposure to particle radioactivity increases biomarkers of inflammation. Our repeated-measures study included 752 men in the greater Boston area. We estimated regional particle radioactivity as a daily spatial average of gross beta concentrations from five monitors in the study area. We used linear mixed-effects regression models to estimate short- and medium-term associations between particle radioactivity and biomarkers of inflammation and endothelial dysfunction, with and without adjustment for additional particulate air pollutants. We observed associations between particle radioactivity on C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), but no associations with fibrinogen. An interquartile range width increase in mean 7-day particle radioactivity (1.2 × 10 Bq/m) was associated with a 4.9% increase in CRP (95% CI = 0.077, 9.9), a 2.8% increase in ICAM-1 (95% CI = 1.4, 4.2), and a 4.3% increase in VCAM-1 (95% CI = 2.5, 6.1). The main effects of particle radioactivity remained similar after adjustment in most cases. We also obtained similar effect estimates in a sensitivity analysis applying a robust causal model. Regional particle radioactivity is positively associated with inflammatory biomarkers, indicating a potential pathway for radiation-induced cardiovascular effects.

Effect of enhanced supply air filtration in buildings on protecting citizens from environmental radioactive particles

The effect of enhanced filtration on protection citizens staying indoor against airborne radionuclides released during nuclear core melt accidents was determined by field measurements using outdoor particles as simulants. An electrically enhanced filter was installed in the HVAC system of an office building and its removal efficiency for particles was altered by using a separate particle charging section in power on and off positions. The effect of air filtration on indoor particle concentrations was determined by using an automated measurement system which was continuously sampling from the outdoor air, filtered supply air and exhaust air. With the aid of the measured outdoor and modelled indoor concentrations the indoor/outdoor ratio of particles of outdoor origin could be accurately determined. External charging of the particles increased the electret filters removal efficiency for 0.4 µrn size particles from 60% to 95%, resulting in decrease of the average I/O ratio of the same size particles from 0.67 to 0.40. Despite the high improvement in the supply air filtration efficiency the indoor concentrations decreased only modestly which is likely due to the leaky construction of the building, demonstrating the detrimental effect of air infiltration on the protection provided by buildings against outdoor airborne hazards. Practical implications: The developed method allows quantification of the key parameters affecting the protection of buildings against outdoor contaminants, thus allowing accurate estimation of size resolved indoor to outdoor ratios for fine particles. The electrically enhanced filter can remove effectively also submicron particles thus reducing the occupant exposure to outdoor hazardous or harmful materials. Best results can be achieved with airtight buildings.

Microscopic Difference of Hydrogen Double-minimum Potential Well Detected by Hydroxyl Group in Hydrogen-bonded System

We investigate the microscopic structure of hydrogen double-well potentials in a hydrogen-bonded ferroelectric system exposed to radioactive particles of hydrogen-ion beams. The hydrogen-bonded system is ubiquitous, forming the base of organic-inorganic materials and the double-helix structure of DNA inside biological materials. In order to determine the difference of microscopic environments, an atomic-scale level analysis of solid-state 1H high-resolution nuclear magnetic resonance (NMR) spectra was performed. The hydrogen environments of inorganic systems represent the Morse potentials and wave function of the eigen state and eigen-state energy derived from the Schrödinger equation. The wave functions for the real space of the localized hydrogen derived from the approximated solutions in view of the atomic scale by using quantum mechanics are manifested by a difference in the charge-density distribution.