• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.447-455
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• 2013

Objectives: This study aims to understand the concentration, diversity, and antibiotic characteristics of staphylococci present in the indoor air of child-care facilities. Methods: Air sampling was performed from October 2012 to January 2013 in 120 child-care facilities in Seoul, Korea. Methicillin-resistant bacteria were selected from the total obtained airborne bacteria and subjected to 16S rRNA analysis for methicillin-resistant staphylococcal species determination. Identified staphylococcal strains were tested for resistance to a range of antibiotics. Results: Average total airborne bacterial concentration was $508.9{\pm}246.3CFU/m^3$. Indoor concentration of total airborne bacteria had a significant positive correlation with the $CO_2$ concentration in the child-care facilities. Methicillin-resistant staphylococci were present in 13.3% of the child-care facilities studied. A total of four species (S. epidermidis, S. cohnii, S. saprophyticus, S. sp.) and 55 strains were identified from the indoor air of the child-care facilities. Staphylococcus cohnii was the most common species (54.5%), followed by S. epidermidis (38.2%). All of the isolated staphylococcal strains exhibited high resistance to oxacillin, erythromycin, mupirocin, and ceftizoxime. Especially, S. saprophyticus strains showed more multidrug resistance to oxacillin, vancomycin, clindamycin, erythromycin, lincomycin, ceftizoxime, mupirocin, and tetracycline than did other species. Conclusion: The results of this study showed that a monitoring system for multidrug-resistant bacteria is needed in facilities for children, as the community-associated infections of these bacteria are increasing.

• Journal of Environmental Health Sciences
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• v.38 no.5
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• pp.415-423
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• 2012

Objectives: This study was performed in order to evaluate antibiotic resistance and analyze the multiple antibiotic resistance of food-borne pathogens isolated from indoor air and an air cleaner at a lunch room in a child care center. Methods: An antibiotic test of food-borne pathogens, including four Staphylococcus aureus and 23 Bacillus cereus was conducted through the disk diffusion method from Clinical and Laboratory Standard Institute. Results: All Staph. aureus was resistant to Ampicillin and Penicillin, while B. cereus was also resistant to Ampicillin, Cefepime and Penicillin. All isolates showed Vancomycin susceptibility but three out of four Staph. aureus and all B. cereus were resistant to Oxacillin. Staph. aureus and B. cereus presented two or more multiple antibiotic resistances. Conclusions: The results indicated that food-borne pathogens isolated from indoor air and an air cleaner at a lunch room in a child care center showed multiple antibiotic resistances. The repeated control of indoor environment quality is required and continuous surveillance of antibiotic resistant strains is demanded.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.5
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• pp.407-417
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• 2016

Effects of resistant starch as a functional substitute on the quality of Yukwa were determined. Replacement ratios of resistant starch were 2, 4, and 6% of glutinous rice flour. Regarding pasting properties of Yukwa dough replaced with resistant starch, initial pasting temperature significantly increased and peak viscosity significantly decreased with increasing resistant starch. The moisture contents of bandegi and Yukwa base replaced with resistant starch were higher than that of the control. The expansion ratio of Yukwa base replaced with resistant starch significantly decreased with increasing resistant starch, and there were no significant differences in the oil absorption ratio. Lightness (L) of Yukwa base replaced with resistant starch increased significantly with increasing resistant starch. Appearance of Yukwa base replaced with resistant starch showed a shortened length and increased width with increasing resistant starch, and cross-section showed an oval shape, fine air cell distribution, and increased outer layer thickness. Hardness and peak number increased significantly with increasing resistant starch. The overall acceptability of Yukwa base replaced with 6% resistant starch was the highest among the samples, but the result was not significant. The above results show that resistant starch substitution in Yukwa improved the texture and further could improve health functionality due to its dietary fiber content. Resistant starch was appropriate as a 6% replacement for glutinous rice flour in Yukwa.

• Journal of Korean Society of Forest Science
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• v.88 no.2
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• pp.221-228
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• 1999

This study measured the seasonal changes in physiological characteristics and antioxidants of Alnus firma to compare several enzyme activities(Rubisco, Superoxide dismutase(SOD) and Glutathione Reductase(GR)) between resistant and sensitive Alnus firma trees. Resistant and sensitive Alnus firma individuals near Yochon industrial complex were selected to conduct this study in 1997. Photosynthetic capacity, stomatal conductance, transpiration, Rubisco, SOD and GR activities of resistant trees which had no visible damages to air pollution were higher than those of sensitive trees in same area. All physiological results supported that biochemical process to be one of the important key features to understand resistance to air pollution. Increases of photosynthetic capacity and antioxidant enzyme activity in resistant trees in response to air pollution were the results of biological compensation to stress.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.709-717
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• 2015

Airborne bacteria from hog farms may have detrimental impacts on human health, particularly in terms of antibiotic resistance and pathogen zoonosis. Despite human health risks, very little is known about the composition and diversity of airborne bacteria from hog farms and hog-related spray fields. We used pyrosequencing analysis of 16S rRNA genes to compare airborne bacterial communities in a North Carolina hog farm and lagoon spray field. In addition, we isolated and identified antibiotic-resistant bacteria from both air samples. Based on 16S rRNA gene pyrosequence analysis, Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria were the dominant phyla in airborne bacterial communities from both hog farm and spray field sites. Within the Firmicutes genera, Clostridium spp. were more abundant in the hog farm, whereas Staphylococcus spp. were higher in the spray field. The presence of opportunitic pathogens, including several Staphylococcus species and Propionibacterium acnes, was detected in both bioaerosol communities based on phylogenetic analysis. The isolation and identification of antibiotic-resistant bacteria from air samples also showed similar results with dominance of Actinobacteria and Proteobacteria in both hog farm and spray field air. Thus, the existence of opportunistic pathogens and antibiotic resistant bacteria in airborne communities evidences potential health risks to farmers and other residents from swine bioaerosol exposure.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.483-487
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• 1992

Among a few number of UV-resistant isolated form various environmental sources (10), we made a comparative physio-chemoanalytical study on one of spherical bacteria isolated from air dust, presumably Deinococcus sp. (CM strain 29) with an UV resistant bacterium, Deinococcus radiophilus ATCC 27603 as the reference strain. Our isolate of UV resistant coccus, Deinococcus sp. CM 29 and D. radiophilus ATCC 27603 showed more than 75% matching coefficient in metabolic activity of various substrates. The most predominant cellular fatty acid of both strains was palmitoleic acid (C 16 :1, cis 9), but the detail fatty acid profiles were slightly dissimilar to each other. Cell-bound arange pigment seemed to be an identical chemicals on spectrophotometric analysis. L-ornithine was detected as cell-wall amino acid in both strains. Galactose was detected as cell-wall sugar in D. radiophilus ATCC 27603, whereas glucose in Deinococcus sp. CM 29. G-C molar ratio of both strains was comparable, 63-65%.

• Journal of Soil and Groundwater Environment
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• v.13 no.6
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• pp.93-102
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• 2008

Experimental studies were conducted to characterize the synthesized nanoscale zero-valent iron (NZVI) which is resistant to oxidation in the atmospheric environment. XRD, XPS, and TEM analyses revealed that the oxidation-resistant NZVI particles formed under various controlled air contact conditions (4, 8 and 12 mL/min) have shells with ${\sim}$5 nm thickness. The shells consist of magnetite (${Fe_3}{O_4}$) and maghemite (${\gamma}-{Fe_2}{O_3}$), predominantly. No substantial differences were found in the shell components and thickness among NZVI particles formed under the various air flow rates. On the other hand, shell was not detected in the TEM image of rapidly oxidized NZVI particles. NZVI particles synthesized under the various air flow rates showed similar TCE degradation performances ($k_{obs}$= 0.111, 0.102, and 0.086 $hr^{-1}$), which are equivalent to approximately 80% of those obtained by the fresh NZVI particles. TCE degradation efficiencies of the NZVI particles(fresh, controlled air contact and rapidly oxidized) were improved after equilibrating with water for one day, indicating that depassivation of the shells occurred. The performances of NZVI particles decreased to 90% and 50% of those of the fresh NZVI particles, when they were equilibrated with the atmosphere for a week and two months, respectively. The NZVI particles synthesized under the controlled air contact would have advantages over traditional NZVI particles in terms of practical application into the site, because of their inertness toward atmospheric oxygen.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.1
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• pp.93-103
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• 1997

The purpose of this study was to investigate the actual performance of Korean firefighter's clothing through comparisons with protective clothing used in the United State, surveys of firefighter's opinion, and experiments on the material used in Korean firefighter's clothing. The paper presents experimental results as well as ways to improve current standards. The major results are as follows: 1. Korean protective clothing is too thin and too heavy. Thicker, lighter, and more heat- resistant fabric and a lighter trim should be used. 2. Korean protective clothing is not very water-resistant. A Water-resistant outershell and an innerliner which are made of air permeable and water resistant fabric must be used. 3. Korean protective clothing's outershell and innerliner should be made of fabric that is more heat-resistant, flame-resistant, and chemical resistant. 4. Protective clothing should be more brightly colored and its reflective tape should have greater reflectivity to make firefighters more visible. 5. The fastner currently used in Korean protective clothing consists of Velcro, a button, and a D-ring which can not be opened and closed quickly. A better fastener would have just velcro and a zipper. 6. The uniform for Korean firefighters consists of only a protective coat and boots. Protective trousers should be added to the standard uniform. Also, a thermal harrier should be used in winter to protect firefighters from the cold. 7. Korean firefighters should be provided with their own personal sets of protective clothing to ensure a proper fit.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.367-373
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• 2021

The antimicrobial resistance of Staphylococcus spp. and Gram negative strains present in air samples from waste sorting facilities was assessed. Phenotypic studies have revealed a high percentage of strains of Staphylococcus spp. resistant to methicillin. Genotypically and by RT-PCR, it was found that the mecA gene usually associated with methicillin resistance was present in 8% of the Staphylococcus strains isolated. About 30% of the Gram negative strains from the same samples also displayed resistance to meropenem and 79% of these were resistant to multiple antibiotics from different classes, namely cephalosporins and β-lactams. The results suggest that in professional activities with high levels of exposure to biological agents, the quantification and identification of the microbial flora in the work environment, with the determination of the presence of potential agents displaying multi-resistances is of relevance to the risk assessment. The personal protection of workers is particularly important relevance in these cases, since many of the strains that exhibit multi-resistance are potential opportunistic agents.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.829-838
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• 2021

Purpose: The Air Spring Damper System (ASDS) is proposed when existing concrete structures that have not been seismic resistant for economic and technical reasons or low-rise concrete structures that are difficult to earthquake. Method: To conduct a study on the damping force antigen in the kinetic equation of free vibration, we analyze whether this device has damping ability as a damper experimentally and theoretically, and examine the possibility of field application. Result: The air damper system is considered to be more economical than steel hysteresis dampers even if the number of dampers increases due to its easy manufacture and construction and low restrictions on shape, size, material, etc. Conclusion: In an air spring damper system, it is essential to reduce the diameter of the air inlet/outlet hole to improve the damping ratio, and in this case, if the diameter exceeds a certain lower limit, consideration of the compressibility of air is required, so further research is needed.