Results of the cytogenetic examination of the people taking part in the clean-up of the accident at the Chernobyl AES]

Chromosome preparations from peripheral blood cells of 117 subjects who took part in liquidation of Chernobyl NPP accident consequences in 1986 have been investigated. The number of chromosome aberrations has been shown to increase considerably. A short-term exposure has been found to be 5-7 times more effective than long-term one.     

An assessment of the permissible level of a mixture of radionuclides from the Chernobyl fallout in human lungs]

The permissible level of a radionuclide mixture, resulted from the Chernobyl burst, in the human being lungs was determined for two kinds of compounds: absolutely insoluble compounds and soluble compounds in the state of equilibrium. For this purpose the data were used concerning the radionuclide composition and aerosol disperse in lower atmosphere which were obtained by the Department for Dosimetric Control (NPO "Pripiat'"). The results of measurements of 137Cs content taken by the use of human radiation spectrometer (HRS) needed an adequate estimation: low level of 137Cs in the human lungs and body within the Chernobyl NPP, zone does not guarantee radiation security. The notion "permissible content" and the possibility of using thereof in the individual dosimetric control are discussed.     

Measurement of resuspended aerosol in the Chernobyl area

Results of measurements of the resuspended radioactive aerosols in the Chernobyl area are presented which were obtained soon after the Chernobyl reactor accident and in a European project in 1992–1993. The measurements were carried out with the intention of obtaining a data base for dose assessment of resuspended radioactive particles. Potential significant dose contributions may result from inhalation and secondary contamination due to resuspended radionuclides. In this first article of a series of three papers, the instrumentation and the measurement uncertainties are discussed. An effort was made to sample quantitatively giant aerosol particles (particles larger than 10 μm aerodynamic diameter) as well. The comparison of the samplers shows, in general, an agreement of concentration measurements of ¹³⁷Cs and ⁷Be within a factor of two. One sampler was identified with larger discrepancies and needs additional investigation of its sampling characteristics; for another device, the recalibration of the analysing system is recommended. Ordinary integrating samplers have a loss of about 30% in ¹³⁷Cs activity compared to an isokinetic sampler collecting giant particles as well. The mean ratio of ¹³⁷Cs activity concentration between an instrument sampling only particles larger than 10 μm and an ordinary integrating sampler is 0.39 ± 0.15 during anthropogenic-enhanced resuspension. These findings demonstrate the significant contribution of giant particles to resuspended airborne radioactivity. The results of this study concerning integral measurements during wind-driven resuspension proved to be in good agreement with previously published data on resuspension. Received: 15 May 1997 / Accepted: 4 August 1997     

The accumulation of radionuclides 137Cs and 90Sr by different kinds and grades legumes crops

The decision of protein problem on contaminated by radionuclides territories as a result of the accident on Chernobyl NPP is not possible without increase of the sowing areas legumes crops (peas, lupine, soybean). Introduction in agricultural manufacture of grades with a low level of accumulation radionuclides (peas--Aist, Polesskay, Gomelskay Agat; soybean--Severnaya zvezda, Mageva) will allow to receive agricultural production adequate "Republican allowable levels of the contents of 137Cs and 90Sr in agricultural raw material and forages" on arable lands at their higher density of radioactive contamination: 137Cs--1300-1480 kBq/m2 (35.0-40.0 Ci/km2): 90Sr--18.5-37.0 kBq/m2 (0.50-1.00 Ci/km2).     

Characterization of aerosols produced by cell sorters and evaluation of containment

Despite the recognition of potential aerosol hazards associated with cell sorting by the flow cytometry community, there has been no previous study that has thoroughly characterized the aerosols that can be produced by cell sorters. In this study, an aerodynamic particle sizer was used to determine the concentration and aerodynamic diameter (AD) of aerosols produced by a FACS Aria II cell sorter under various conditions. Aerosol containment and evacuation were also evaluated using this novel methodology. The results showed that high concentrations of aerosols in the range of 1-3 μm can be produced in fail mode and that with decreased sheath pressure, aerosol concentration decreased and AD increased. Although the engineering controls of the FACS Aria II for containment were effective, sort chamber evacuation of aerosols following a simulated nozzle obstruction was ineffective. However, simple modifications to the FACS Aria II are described that greatly improved sort chamber aerosol evacuation. The results of this study will facilitate the risk assessment of cell sorting potentially biohazardous samples by providing much needed data regarding aerosol production and containment.     

Strategies to Reduce Tin and Other Metals in Electronic Cigarette Aerosol

Background

Metals are present in electronic cigarette (EC) fluid and aerosol and may present health risks to users.

Objective

The objective of this study was to measure the amounts of tin, copper, zinc, silver, nickel and chromium in the aerosol from four brands of EC and to identify the sources of these metals by examining the elemental composition of the atomizer components.

Methods

Four brands of popular EC were dissected and the cartomizers were examined microscopically. Elemental composition of cartomizer components was determined using integrated energy dispersive X-ray microanalysis, and the concentrations of the tin, copper, zinc silver, nickel, and chromium in the aerosol were determined for each brand using inductively coupled plasma optical emission spectroscopy.

Results

All filaments were made of nickel and chromium. Thick wires were copper coated with either tin or silver. Wires were joined to each other by tin solder, brazing, or by brass clamps. High concentrations of tin were detected in the aerosol when tin solder joints were friable. Tin coating on copper wires also contributed to tin in the aerosol.

Conclusions

Tin concentrations in EC aerosols varied both within and between brands. Tin in aerosol was reduced by coating the thick wire with silver rather than tin, placing stable tin solder joints outside the atomizing chamber, joining wires with brass clamps or by brazing rather than soldering wires. These data demonstrate the feasibility of removing tin and other unwanted metals from EC aerosol by altering designs and using materials of suitable quality.     

Effect of dust and anthropogenic aerosols on columnar aerosol optical properties over Darjeeling (2200 m asl), eastern Himalayas, India

Background

The loading of atmospheric particulate matter (aerosol) in the eastern Himalaya is mainly regulated by the locally generated anthropogenic aerosols from the biomass burning and by the aerosols transported from the distance sources. These different types of aerosol loading not only affect the aerosol chemistry but also produce consequent signature on the radiative properties of aerosol.

Methodology/Principal Findings

An extensive study has been made to study the seasonal variations in aerosol components of fine and coarse mode aerosols and black carbon along with the simultaneous measurements of aerosol optical depth on clear sky days over Darjeeling, a high altitude station (2200 masl) at eastern Himalayas during the year 2008. We observed a heavy loading of fine mode dust component (Ca²⁺) during pre-monsoon (Apr – May) which was higher by 162% than its annual mean whereas during winter (Dec – Feb), the loading of anthropogenic aerosol components mainly from biomass burning (fine mode SO₄ ²⁻ and black carbon) were higher (76% for black carbon and 96% for fine mode SO₄ ²⁻) from their annual means. These high increases in dust aerosols during pre-monsoon and anthropogenic aerosols during winter enhanced the aerosol optical depth by 25 and 40%, respectively. We observed that for every 1% increase in anthropogenic aerosols, AOD increased by 0.55% during winter whereas for every 1% increase in dust aerosols, AOD increased by 0.46% during pre-monsoon.

Conclusion/Significance

The natural dust transport process (during pre-monsoon) plays as important a role in the radiation effects as the anthropogenic biomass burning (during winter) and their differential effects (rate of increase of the AOD with that of the aerosol concentration) are also very similar. This should be taken into account in proper modeling of the atmospheric environment over eastern Himalayas.     

Characterization and Deposition of Respirable Large- and Small-Particle Bioaerosols

The deposition patterns of large-particle microbiological aerosols within the respiratory tract are not well characterized. A novel system (the flow-focusing aerosol generator [FFAG]) which enables the generation of large (>10-μm) aerosol particles containing microorganisms under laboratory conditions was characterized to permit determination of deposition profiles within the murine respiratory tract. Unlike other systems for generating large aerosol particles, the FFAG is compatible with microbiological containment and the inhalational challenge of animals. By use of entrapped Escherichia coli cells, Bacillus atrophaeus spores, or FluoSphere beads, the properties of aerosols generated by the FFAG were compared with the properties of aerosols generated using the commonly available Collison nebulizer, which preferentially generates small (1- to 3-μm) aerosol particles. More entrapped particulates (15.9- to 19.2-fold) were incorporated into 9- to 17-μm particles generated by the FFAG than by the Collison nebulizer. The 1- to 3-μm particles generated by the Collison nebulizer were more likely to contain a particulate than those generated by the FFAG. E. coli cells aerosolized using the FFAG survived better than those aerosolized using the Collison nebulizer. Aerosols generated by the Collison nebulizer and the FFAG preferentially deposited in the lungs and nasal passages of the murine respiratory tract, respectively. However, significant deposition of material also occurred in the gastrointestinal tract after inhalation of both the small (89.7%)- and large (61.5%)-particle aerosols. The aerosols generated by the Collison nebulizer and the FFAG differ with respect to mass distribution, distribution of the entrapped particulates, bacterial survival, and deposition within the murine respiratory tract.     

The phospholipid composition of the liver in root voles living under different radioecological conditions

The effect of the increased natural radiation background (within some areas in Komi Republic) and man-caused radioactive contamination in the Chernobyl NPP accident zone on the composition of liver phospholipids in Microtus oeconomus inhabiting these areas was studied. The significant changes in the liver lipid composition in rodents inhabiting both the Chernobyl accident zone and the areas with the increased natural radiation background were found. The maximal changes in the liver phospholipid composition were revealed during the first year after the accident. The reverse dependence between the phosphatidyl choline/phosphatidyl ethanolamine ratio and the ratio between the sum of more readily oxidizable phospholipids and the sum of more poorly oxidizable ones was found. However, the slope of corresponding curves significantly depends on the radioactive state in the area of the population inhabitance. The conclusion about high sensitivity of the lipid composition of hepatocytes in Microtus oeconomus both to the impact of the man-caused radioactive contamination and the increased level of the natural radioactivity was drawn.     

Influenza Virus Aerosols in Human Exhaled Breath: Particle Size,Culturability, and Effect of Surgical Masks

The CDC recommends that healthcare settings provide influenza patients with facemasks as a means of reducing transmission to staff and other patients, and a recent report suggested that surgical masks can capture influenza virus in large droplet spray. However, there is minimal data on influenza virus aerosol shedding, the infectiousness of exhaled aerosols, and none on the impact of facemasks on viral aerosol shedding from patients with seasonal influenza.We collected samples of exhaled particles (one with and one without a facemask) in two size fractions (“coarse”>5 µm, “fine”≤5 µm) from 37 volunteers within 5 days of seasonal influenza onset, measured viral copy number using quantitative RT-PCR, and tested the fine-particle fraction for culturable virus.Fine particles contained 8.8 (95% CI 4.1 to 19) fold more viral copies than did coarse particles. Surgical masks reduced viral copy numbers in the fine fraction by 2.8 fold (95% CI 1.5 to 5.2) and in the coarse fraction by 25 fold (95% CI 3.5 to 180). Overall, masks produced a 3.4 fold (95% CI 1.8 to 6.3) reduction in viral aerosol shedding. Correlations between nasopharyngeal swab and the aerosol fraction copy numbers were weak (r = 0.17, coarse; r = 0.29, fine fraction). Copy numbers in exhaled breath declined rapidly with day after onset of illness. Two subjects with the highest copy numbers gave culture positive fine particle samples.Surgical masks worn by patients reduce aerosols shedding of virus. The abundance of viral copies in fine particle aerosols and evidence for their infectiousness suggests an important role in seasonal influenza transmission. Monitoring exhaled virus aerosols will be important for validation of experimental transmission studies in humans.     

Tracheobronchial irritancy of inhaled prostaglandins in the conscious cat

A novel test was developed to measure the tracheobronchial irritant activity of inhaled prostaglandins. Conscious restrained cats were challenged with separate aerosols of PGE1, PGF2alpha, acetylcholine or isoprenaline. All of the aerosols except isoprenaline caused coughing in a concentration related manner. Tolerance developed very quickly to the tracheobronchial irritation and lasted 1-2 days for PGE1 and less than 1 day for PGF2alpha and acetylcholine. When a 3 day interval between each aerosol challenge was used, PGF2alpha was approximately 700 times more potent than acetylcholine as a tracheobronchial irritant. The highest PGE1 aerosol concentration (500microgram/ml) also caused sedation, diarrhoea and salivation. This test probably provides a useful method for evaluating the tracheobronchial irritant activity of potential prostaglandin bronchodilator analogues and for investigating the mechanism of action of prostaglandin induced tracheobronchial irritancy.     

Detecting Lung Diseases from Exhaled Aerosols: Non-Invasive Lung Diagnosis Using Fractal Analysis and SVM Classification

Background

Each lung structure exhales a unique pattern of aerosols, which can be used to detect and monitor lung diseases non-invasively. The challenges are accurately interpreting the exhaled aerosol fingerprints and quantitatively correlating them to the lung diseases.

Objective and Methods

In this study, we presented a paradigm of an exhaled aerosol test that addresses the above two challenges and is promising to detect the site and severity of lung diseases. This paradigm consists of two steps: image feature extraction using sub-regional fractal analysis and data classification using a support vector machine (SVM). Numerical experiments were conducted to evaluate the feasibility of the breath test in four asthmatic lung models. A high-fidelity image-CFD approach was employed to compute the exhaled aerosol patterns under different disease conditions.

Findings

By employing the 10-fold cross-validation method, we achieved 100% classification accuracy among four asthmatic models using an ideal 108-sample dataset and 99.1% accuracy using a more realistic 324-sample dataset. The fractal-SVM classifier has been shown to be robust, highly sensitive to structural variations, and inherently suitable for investigating aerosol-disease correlations.

Conclusion

For the first time, this study quantitatively linked the exhaled aerosol patterns with their underlying diseases and set the stage for the development of a computer-aided diagnostic system for non-invasive detection of obstructive respiratory diseases.     

Dispersal of Septoria nodorum Pycnidiospores by Simulated Rain and Wind

The influence of wind on the splash dispersal of Septoria nodorum pycnidiospores was studied in a raintower/wind tunnel complex with single drops or simulated rain falling on spore suspensions or infected stubble with windspeeds of 1.5 to 4 m/sec. When single drops fell on spore suspensions (depth 0.5 mm, concentration 7.8 × 10⁵ spores/ml) most of the spore-carrying droplets collected on fixed photographic film between 0–4 m downwind (windspeed 3 m/sec) were >200 μm in diameter. However, most spores were carried in droplets with diameter > 1000 μm, 70 % of which carried more than 100 spores. When simulated rain fell on infected stubble most of the spore-carrying droplets collected beyond 1 m downwind (windspeeds 1.4 and 4 m/sec) were <200 μm in diameter and none were >600 μm; most of these droplets carried only one spore. The distribution of splash droplets (with diameter >100 μm) deposited on chromatography paper showed a maximum at 40–50 cm upwind of the target but many more droplets were deposited 20–30 cm downwind, when single drops fell on a spore suspension (concentration 1.2 × 10⁵ spores/ ml) containing fluorescein dye with a windspeed of 2 m/sec; droplets were collected up to 3 m downwind but not more than 70 cm upwind. With a windspeed of 3 m/sec, numbers of sporecarrying droplets and spores collected on film decreased with increasing distance downwind; most were collected within 2 m of the target but some were found up to 4 m. When simulated rain fell on infected stubble, increasing the windspeed from 1.5 to 4 m/sec greatly increased the number of spores deposited more than 1 m downwind. At 1.5 m/sec none were collected beyond 2 m downwind, whereas at 4 m/sec some were collected at 4 m. A few air-borne S. nodorum spores were collected by suction samplers at a height of 40 cm at distances up to 10 m downwind of a target spore suspension on which simulated rain fell.     

Determining the basic characteristics of aerosols suitable for studies of deposition in the respiratory tract

Studies of aerosol particle deposition in the respiratory tract requires experimental inhalation of artificial model aerosols. The paper formulates some of the most important requirements for the properties of such aerosols. Several suitable fractions were prepared as part of a research project dealing with the use of microporous polymers for diagnostic purposes. 5 fractions of the polymer designated G-gel 60 with the particle size as stated by the manufacturer, ranging from 3 to 7 micron were evaluated using a 16-channel particle dispersity analyzer HIAC/ROYCO MT 3210 with the sensor 1200 and operated by a microprocessor, the equipment being coupled to an APPLE IIe computer. G-gel 60 particles introduced into the aerosol were characterized by the parameters CMAD, MMAD and sg both numerically and graphically. The measurement procedure was found to be very sensitive with respect to all fractions in evaluating the subtile differences between different lot numbers of the aerosol. G-gel 60 fractions characterized both numerically and graphically were compared with the known aerosols from paraffin oil and atmospheric air. The equipment MT 3210 enables prompt determination of the percentages of aerosol particles distribution by size class. The authors conclude that the procedure, both in its numerical and graphical versions, is particularly suitable for the diagnosis of aerosol particles deposition in the respiratory tract, offering a new application for HIAC/ROYCO in the field of medicine. In evaluating atmospheric aerosol in exhaled air, the number of particles was found to be below that in inhaled air, the difference being dependent on the choice of investigation methods. Percentual distribution of deposited particles following one minute ventilation proved to be at its maximum, as regards atmospheric aerosol, in the 0.30-0.50 micron range. The deposition curve was similar to already published curves, being characterized by an S-shaped pattern with maximum deposition in the greater size classes. An analysis of inhaled, exhaled and deposited aerosol suggested that deposited aerosol is more polydisperse and has particles of greater sizes than inhaled aerosol. Investigation of the effect of apnoe on deposition indicated that deposition increased as a function of apnoeic pause.     

Aerial contamination of agroecosystems following the accident at the Chernobyl Nuclear plant

The regularities of the aerial contamination of agricultural ecosystems are described in the early period after the Chernobyl NPP accident. The aerial contamination is shown to be caused by the development of the above-ground biomass of plants and fallout characteristics. A specific coefficient of primary retention varied between 0.46 and 1.2 m2 kg-1 for 137Cs. The first half-life period varies from 9.7 to 13.4 days. The second period varies from 46.2 to 52.2 days. It has been found that parameters of aerial contamination from the Chernobyl accident well correlate with the results of observation in the period of global fallout.     

Rheological investigation of synergistic interactions between galactomannans and non-pectic polysaccharide fraction from water soluble yellow mustard mucilage

Synergistic interactions between galactomannans (GMs) and non-pectic polysaccharides (NPP) from yellow mustard mucilage were investigated in the present study. Structural analysis revealed that NPP was mainly composed of β-1,4-d glucosidic linkage. Four types of GMs, namely fenugreek gum (FG), guar gum (GG), tara gum (TG) and locust bean gum (LBG) with mannose to galactose ratios (M/G) of 1.2, 1.7, 3.0 and 3.7, respectively, were blended with NPP at various ratios. The viscoelastic properties of the mixtures were measured in order to evaluate the effects of GM/NPP blending ratio, M/G ratio, total polysaccharide concentration and pH on the synergistic interactions. Results revealed that at a total polysaccharide concentration of 0.5% (w/w), the highest synergism occurred at the GM/NPP blending ratio of 3/7 for all four types of GMs. The interaction between TG and NPP showed the highest synergy, followed by LBG/NPP, FG/NPP and GG/NPP. At a higher total polysaccharide concentration (1.0% w/w), the mixture of TG and NPP still exhibited the highest synergy, however, the order of synergy between NPP and other GMs was changed as FG/NPP, LBG/NPP and GG/NPP. At the total polysaccharide concentration of 0.5% and GM/NPP blending ratio of 3/7, neutral pH (pH 6.5) showed the strongest synergy compared to that at pH 2.0 and pH 12.0. The mechanism of the synergistic effects could be explained by a combination of segregative association model and junction zone model.     

Analysis of allergens in ambient aerosols: Comparison of areas subjected to different levels of air pollution

Recent studies describe interactions of pollen surfaces with aerosol particles; pollen surfaces undergo morphological changes and the release of allergens and allergenic fragments from the pollen can be enhanced. Thus allergens from pollen can be found in particle size fractions much smaller than undamaged pollen (<5m). This may explain allergic reactions in parts of the lungs which cannot be reached by undamaged pollen. In Switzerland the birch tree (betula verrucosa) major allergen Bet v 1 and the grass (phleum pratense) pollen major allergen Phl p 5 are of particular relevance for inducing pollinosis. In this study aerosols of different aerodynamic diameters were sampled by Andersen-Impactors over 18 months. Sampling areas are subjected to different levels of air pollution (Zürich, Switzerland, urban; Payerne, Switzerland, rural: Davos, Switzerland, alpine). Samples were scanned by electron microscopy and submitted to specific allergen assays (ELISA) for birch pollen major allergen Bet v 1 and grass pollen major allergen Phl p 5 respectively. Particle and major allergen concentrations were highest in Zürich, followed by Payerne and, significantly lower, Davos. Scanning electron microscopy investigations showed interactions of aerosols with pollen surfaces in Zürich and Payerne. The presence of Bet v 1 in smaller aerosol fractions was demonstrated in Zürich and Payerne some weeks before and after birch pollen was counted.     

Comparison of coliphage and bacterial aerosols at a wastewater spray irrigation site.

Microbiological aerosols were measured on a spray irrigation site at Fort Huachuca, Ariz. Indigenous bacteria and tracer bacteriophage were sampled from sprays of chlorinated and unchlorinated secondary-treatment wastewaters during day and night periods. Aerosol dispersal and downwind migration were determined. Bacterial and coliphage f2 aerosols were sampled by using Andersen viable type stacked-sieve and high-volume electrostatic precipitator samplers. Bacterial standard plate counts averaged 2.4 x 10(5) colony-forming units per ml in unchlorinated effluents. Bacterial aerosols reached 500 bacteria per m3 at 152 m downwind and 10,500 bacteria per m3 at 46m. Seeded coliphage f2 averaged 4.0 x 10(5) plaque-forming units per ml in the effluent and were detected 563 m downwind. Downwind microbial aerosol levels were somewhat enhanced by nighttime conditions. The median aerodynamic particle size of the microbial aerosols was approximately 5.0 micrometer. Chlorination reduced wastewater bacterial levels 99.97% and reduced aerosol concentrations to near background levels; coliphage f2 was reduced only 95.4% in the chlorinated effluent and was readily measured 137 m downwind. Microbiological source strength an meteorological data were used in conjunction with a dispersion model to generate mathematical predictions of aerosol strength at various sampler locations. The mean calculated survival of aerosolized bacteria (standard plate count) in the range 46 to 76 m downwind was 5.2%, and that of coliphage f2 was 4.3 %.     

Hydrolysis of diadenosine polyphosphates by nucleotide pyrophosphatases/phosphodiesterases.

Diadenosine polyphosphates (ApnAs) act as extracellular signaling molecules in a broad variety of tissues. They were shown to be hydrolyzed by surface-located enzymes in an asymmetric manner, generating AMP and Apn-1 from ApnA. The molecular identity of the enzymes responsible remains unclear. We analyzed the potential of NPP1, NPP2, and NPP3, the three members of the ecto-nucleotide pyrophosphatase/phosphodiesterase family, to hydrolyze the diadenosine polyphosphates diadenosine 5',5"'-P1,P3-triphosphate (Ap3A), diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A), and diadenosine 5',5"'-P1,P5-pentaphosphate, (Ap5A), and the diguanosine polyphosphate, diguanosine 5',5"'-P1,P4-tetraphosphate (Gp4G). Each of the three enzymes hydrolyzed Ap3A, Ap4A, and Ap5A at comparable rates. Gp4G was hydrolyzed by NPP1 and NPP2 at rates similar to Ap4A, but only at half this rate by NPP3. Hydrolysis was asymmetric, involving the alpha,beta-pyrophosphate bond. ApnA hydrolysis had a very alkaline pH optimum and was inhibited by EDTA. Michaelis constant (Km) values for Ap3A were 5.1 micro m, 8.0 micro m, and 49.5 micro m for NPP1, NPP2, and NPP3, respectively. Our results suggest that NPP1, NPP2, and NPP3 are major enzyme candidates for the hydrolysis of extracellular diadenosine polyphosphates in vertebrate tissues.