• Toxicological Research
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• v.30 no.2
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• pp.83-90
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• 2014

An increasing number of recent studies have focused on the impact of particulate matter on human health. As a model for atmospheric particulate inhalation, we investigated the effects of inhaled carbon black nanoparticles (CBNP) on mice with bleomycin-induced pulmonary fibrosis. The CNBPs were generated by a novel aerosolization process, and the mice were exposed to the aerosol for 4 hours. We found that CBNP inhalation exacerbated lung inflammation, as evidenced by histopathology analysis and by the expression levels of interleukin-6 protein, fibronectin, and interferon-${\gamma}$ mRNAs in lung tissues. Notably, fibronectin mRNA expression showed a statistically significant increase in expression after CBNP exposure. These data suggest that the concentration of CBNPs delivered (calculated to be $12.5{\mu}g/m^3$) can aggravate lung inflammation in mice. Our results also suggest that the inhalation of ultrafine particles like PM 2.5 is an impactful environmental risk factor for humans, particularly in susceptible populations with predisposing lung conditions.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.1-9
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• 2020

Objectives: The purpose of this case study is to assess workers' exposure to carbon nanotubes(CNTs) and characterize particles aerosolized during the process of producing CNT-enabled polytetrafuoroethylene(PTFE) composites at a worksite in Korea. Methods: Personal breathing zone and area samples were collected for determining respirable concentrations of elemental carbon(EC) using NIOSH(National Institute for Occupational Safety and Health) Method 5040. Personal exposure to nano-sized particles was measured as the number concentration and mean diameter using personal ultrafine particle monitors. The number concentration by particle size was measured using optical particle sizers(OPS) and scanning mobility particle sizers(SMPS). Transmission electron microscopy (TEM) area samples were collected on TEM grids and analyzed to characterize the size, morphology, and chemistry of the particles. Results: Respirable EC concentrations ranged from 0.04 to 0.24 ㎍/㎥, which were below 23% of the exposure limit recommended by NIOSH and lower than background concentrations. Number concentrations by particle size measured using OPS and SMPS were not noticeably elevated during CNT-PTFE composite work. Instant increase of number concentrations of nano-sized particles was observed during manual sanding of CNT-PTFE composites. Both number concentrations and mean diameters did not show a statistically significant difference between workers handing CNT-added and not-added materials. TEM analyses revealed the emission of free-standing CNTs and CNT-PTFE aggregate particles from the powder supply task and composite particles embedded with CNTs from the computer numerical control(CNC) machining task with more than tens of micrometers in diameter. No free-standing CNT particles were observed from the CNC machining task. Conclusions: Significant worker exposure to respirable CNTs was not found, but the aerosolization of CNTs and CNT-embedded composite particles were observed during handing of CNT-PTFE powders and CNC machining of CNT-PTFE composites. Considering the limited knowledge on the toxicity of CNTs and CNT composite particles to date, it seems prudent to take a precautionary approach for the protection of workers' health.

• Korean Journal of Microbiology
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• v.53 no.3
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• pp.156-162
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• 2017

Legionnaires' disease (LD) is a severe and potentially fatal pneumonia caused by colonization of human-made water system and subsequent aerosolization and inhalation of Legionella bacteria. A total of 147 Legionella strains was isolated from environmental water sources from public facilities in Gyeonggi-do, South Korea. The distribution of Legionella isolates was investigated according to facility type, and sample type. L. pneumophila was distributed broadly throughout Gyeonggi-do, accounting for 85.7% of the isolates, and L. pneumophila serogroup (sg) 1 predominated in all of the public facilities. L. wadsworthii predominated among non-L. pneumophila species. We performed comparative analyses of L. pneumophila sg 1 isolated from environment water of public facilities in Gyeonggi-do by pulsed field gel electrophoresis (PFGE) and sequence-based typing (SBT). Thirty-two isolates were classified into 22 types by PFGE and 9 sequence types (STs) by SBT and categorized into 3 groups. ST1 was the most prevalent sequence type and two STs obtained in this study had unique allelic profiles. The use of SBT data from different countries for epidemiology study of LD constitutes a technically uncomplicated and relatively easy method for strain subtyping, especially compared to other contemporary techniques.

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.336-341
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• 2011

This study was carried out to investigate efficacy of aerosol sanitizer with natural antimicrobial and organic acids against Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The artificially inoculated pathogens on stainless steel coupon were treated with grapefruit seed extract (GFE), acetic acid, citric acid and lactic acid in model cabinet for 5 min. The number of three foodborne pathogens with individual treatment was reduced by 0.34-3.77 log units, treatment with GEF + organic acid was reduced by 1.72-3.89 log units and treatment with GEF + organic acid + alcohol was reduced by 1.46-5.05 log units. By treatment with GEF + lactic acid + alcohol in scale-up model system for 10 min. Populations of E. coli O157:H7, S. Typhimurium and L. monocytogenes were reduced by 3.42, 2.72 and 2.30 log units from the untreated control respectively. From the above result, aerosol sanitizer with natural antimicrobial agents and organic acid can be used as an environmental sanitation method with satisfying the consumer demand on safe food.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.204-211
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• 2012

Although Arcobacter butzleri is a foodborne emerging pathogen causing gastroenteritis in human and animals, there are a few researches on the physical and chemical control methods. The aim of this study was to investigate the effect of ultraviolet radiation or ethanol treatment on A. butzleri. To demonstrate the UV effect, 8 ${\log}_{10}CFU$/mL of A. butzleri were spiked on stainless steel and the pork was then exposed to 250 nm of ultraviolet light for 108-648 mWs/$cm^2$. To ascertain the effect of ethanol, A. butzleri and A. butzleri spiked pork were soaked or sprayed 10, 35 and 70% of ethanol for 10 to 30 min. A. butzleri significantly decreased all of the UV doses in stainless steel, whereas, the reduction was just $0.92{\pm}0.62-1.29{\pm}0.34\;{\log}_{10}CFU$/mL in pork spiked with A. butzleri. In the ethanol groups, A. butzleri decreased significantly in 35% or 70% of ethanol in contrast, the bacterial counts were dropped slightly in A. butzleri spiked pork groups. Therefore, it is necessary to develop various kinds of control methods or hurdle technology for A. butzleri.

• Korean Journal of Medicinal Crop Science
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• v.18 no.6
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• pp.389-397
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• 2010

This work was to improve antimicrobial activities of horseradish by encapsulated with edible biopolymers such as lecithin and gelatin since it has been difficult to directly use horseradish extracts into foods and food containers due to its strong and undesirable flavors. It was shown that most of the nanoparticles containing the extracts were well formed in round shape with below 400 nm diameter as well as fairly stable and less odd flavors in various pH ranges by measuring zeta potentials. The encapsulation efficiencies of nanoparticles were estimated as 66.6% and 53.4% for lecithin and gelatin, respectively. Minimal Inhibitory Concentration (MIC) of both nanoparticles against G(+), Listeria monocytogenes and G(-), Salmonella typhimurium were also measured as 79 ppm based on AIT concentrations in the extracts, whose activities were about 65% higher than the case of adding crude extract. It was also found that the nanoparticles efficiently penetrated into the cell membrane and started to destruct the cells after 6 hours cultivation under Transmision Electron Microscopy observation. These results prove that the nano-encapsulation of the horseradish extracts can be employed to directly treat into the foods and food containers for antimicrobial purposes with the aids of aerosolization system, by using small amounts of the extracts and having less flavors due to masking effects of nanoparticles.