• Journal of the Korean Wood Science and Technology
• /
• v.22 no.1
• /
• pp.20-27
• /
• 1994

Water repellent preservative (WRP) treated and untreated, small-sized specimens prepared from semiwater resistant, water resistant, and tegofilm-overlaid plywood were exposed to outdoor weathering for one year. Exterior durability of specimens was evaluated on the basis of changes in dynamic modulus of elasticity, degree of delamination, modulus of elasticity, modulus of rupture, and glueline shear strength. Among untreated specimens, tegofilm-overlaid plywood showed the best outdoor durability, and durability between semiwater resistant and water resistant plywood was similar. Although WRP treatment increased the durability of all types of plywoods, the effect of treatment on the increase in durability for semi water resistant plywood was not distinct. Accordingly, it can be concluded that semi water resistant plywood, which is used for temporary construction such as concrete formwork in our country, can not be inadequate for exterior use, regardless of WRP treatment. The bending strength and glueline shear strength of untreated water resistant plywood measured after weathering for one year did not exceed the minimum value specified by Korean Standard (KS), thereby the outdoor use of water resistant plywood was not desirable without WRP treatment. Exterior durability between treated water resistant plywood and untreated tegofilm-overlaid plywood was very similar. This result suggests that if an exposed plywood surface is treated with WRP regularly water resistant plywood can be used for temporary construction. This suggestion, however, needs to be investigated. In summary, semiwater resistant plywood cannot be used for temporay construction regardless of WRP treatment. Water resistant plywood can be used only with WRP treatment. Comparing the cost of tegofilm-overlaid plywood to costs of water resistant plywood and WRP treatment, however, it can be concluded that use of tegofilm-overlaid plywood for temporay constrution is strongly suggested from the point of view of both outdoor durability and costs.

• Journal of Environmental Health Sciences
• /
• v.41 no.1
• /
• pp.40-48
• /
• 2015

Objectives: This study aims to understand the concentration, diversity, and antibiotic characteristics of oxytetracycline resistant bacteria present in a surface water environment. Methods: Water sampling was performed in Cheongmi Stream in Gyeonggi-do, Korea in February and August 2014. Water samples collected from two sites were plated in triplicate on tryptic soy agar plates with 30 mg/L of oxytetracycline. Oxytetracycline resistant bacteria were selected from surface water in Cheongmi Stream and were subjected to 16S rDNA analysis for oxytetracycline resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Results from this study indicate that the dominant resistant organisms in this aquatic environment are from family Acinetobacter and family Aeromonas. As to culturable heterotrophic bacteria, Oxytetracycline resistant bacteria were present 0.45-0.93% during winter and 0.08-0.38% during summer. Most oxytetracycline resistant bacteria exhibited resistance to more than ten of the antibiotics studied. The diversity of oxytetracycline resistant bacteria in winter was higher than in summer. Conclusion: Most of these resistant bacteria are Gram negative and are closely related to pathogenic species. These results suggest that increasing multi-antibiotic resistant bacteria in the surface water environment has a close relation to the reckless use of antibiotics in livestock.

• Journal of Environmental Health Sciences
• /
• v.42 no.6
• /
• pp.409-418
• /
• 2016

Objectives: The purpose of this study was to characterize penicillin G resistant bacteria in surface water from pharmaceutical complex effluent. Methods: Surface water was sampled from pharmaceutical complex effluent in Gyeonggi-do Province, Korea in March 2015. Water samples were plated in triplicate on tryptic soy agar plates with 32 mg/L of penicillin G. Penicillin G resistant bacteria were selected from the effluent and subjected to 16S rRNA analysis for the penicillin G resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Penicillin G resistant bacteria were present at 8.0% in terms of culturable heterotrophic bacteria. Identified penicillin G resistant bacteria exhibited resistance to more than nine of the antibiotics studied. These resistant bacteria are gram negative and are closely related to pathogenic species. Conclusion: Multi-antibiotic resistant bacteria in the surface water of pharmaceutical complex effluent suggest the need for disinfection and advanced oxidation processed for pharmaceutical effluent.

• Journal of Environmental Health Sciences
• /
• v.15 no.1
• /
• pp.63-73
• /
• 1989

The purposes of this study were to find out the heavy metal and antibiotic resistant coliform bacteria from mineral water and the resistant factors. For the experiment, mineral water samples were taken from A area and B area during the period from march to July, 1988. The results of the experiment were as follows 1. From mineral water, eleven resistant coliforms and one susceptible coliform were isolated. 2. All resistant isolates harbored diverse plasmids of ranged ca. 14-54kb. 3. Susceptible coliform harbored a only plasmid of ca. 2.8 kb. 4. All resistant isolates harbored common size of plasmid of ca. 14kb. 5. As a result of the transformation and agarose gel electrophoresis experiments, resistant factor was R-plasmid. In conclusion, It is suggested that heavy metal contamination of mineral water is the selective pressure for the plasmid encoding the tolerance. Heavy metal resistance, in some case, is present with antibiotic resistance. Therefore, heavy metal contamination of mineral water induces antibiotic resistant bacteria.

• Journal of Environmental Health Sciences
• /
• v.42 no.1
• /
• pp.34-40
• /
• 2016

Objectives: This study aims to examine the concentration, diversity, and antibiotic characteristics of penicillin G resistant enterobacteria present in pharmaceutical effluent. Methods: Water sampling was performed from a pharmaceutical company in Gyeonggi-do Province, Korea in March 2015. Water samples were plated in triplicate on tryptic soy agar plates with 32 mg/L of penicillin G. Penicillin G resistant enterobacteria were selected from the effluent and were subjected to 16S rRNA analysis for penicillin G resistant species determination. Identified resistant strains were tested for resistance to various antibiotics. Results: Penicillin G resistant enterobacteria were present at 6.2% as to culturable heterotrophic bacteria. Identified penicillin G resistant enterobacteria exhibited resistance to more than 10 of the antibiotics studied. These resistant bacteria are gram negative and are closely related to pathogenic species. Conclusion: Multi-antibiotic resistant bacteria in the effluent suggest a need for disinfection and advanced oxidation processes for pharmaceutical effluents.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06b
• /
• pp.459-463
• /
• 2006

For the purpose of developing liner board for water-resistant corrugated board in the cold chain system, several types of base paper for corrugated board were purchased from the market and 6 different boards were produced in the paperboard mill by applying the chemicals on the base paper. Then, water-moisture resistant performance and physical properties of the boards were evaluated and compared each other. The liner board which is dried at high temperature with pressure by the Condebelt showed a superior performance in strength over conventional liner boards. Strength of the board increased by surface chemical treatment up to 60% of compressive strength and 30% of bursting strength. Starch insolubilization with Ammonium-Zirconium -Carbonate and surface coating with a surface size and a moisture resistant chemical on CK paper showed the best result. Therefore, this method was recommended to produce the outer liner board for water -resistant corrugated board.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.2
• /
• pp.29-34
• /
• 2012

For the purpose of developing liner board for water-resistant corrugated board in the cold chain system, several types of base paper for corrugated board were purchased from the market and 6 different boards were produced in the paperboard mill by applying the chemicals on the base paper. Then, water-moisture resistant performance and physical properties of the boards were compared each other. The liner board which is dried at high temperature with pressure by Condebelt papermaking system(CK paper) showed a superior performance in strength over common liner boards. Strength of the board increased by surface chemical treatment up to 60% of compressive strength and 30% of bursting strength. Starch insolubilization with Ammonium-Zirconium Carbonate(AZC) and surface coating with a surface size and a moisture resistant chemical on CK paper showed the best result. Therefore, this method was recommended to produce the outer liner board for water -resistant corrugated board.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.37 no.2 s.110
• /
• pp.70-77
• /
• 2005

For the purpose of developing liner board for water resistant corrugated board in the cold chain system, several types of base paper for corrugated board were purchased from the market and 6 different boards were produced in the mill by applying the chemicals, chosen in the previous studies, on the base paper. Then water-moisture resistance and physical properties of the boards were compared each other. The liner board which is dried at high temperature with pressure by Condebelt (CK paper) showed a superior performance in strength over common liner boards. Strength of the board increased by surface chemical treatment up to $60\%$ of compressive strength and $30\%$ of burst strength. Starch insolubilization with Ammonium Zirconium Carbonate and surface coating with a surface sizing agent and a moisture resistant chemical on CK paper showed the best result. Therefore this method was recommended to produce the outer liner board for water resistant corrugated board.

• The Journal of Korean Medicine
• /
• v.23 no.3
• /
• pp.223-232
• /
• 2002

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) CCARM 3251 and S. aureusKCTC 1928 have been known to be resistant to many kinds of antibiotics. The extract of Glycyrrhizae Radix showed antibacterial activity against MRSA and antibiotics-resistant S. aureus. Methods : We examined the effects of the water-soluble extract and the methanol-soluble extract of Glycyrrhizae Radix on MRSA and antibiotic-resistant S. aureus. The methanolic extract was further fractionated with organic solvents such as hexane, chloroform, and ethyl acetate in that order. Results and Conclusions : The methanol-soluble extract of Glycyrrhizae Radix showed relatively high antibacterial activity against MRSA and antibiotic-resistant S. aureus. However, the water-soluble extract of Glycyrrhizae Radix showed no antibacterial activity against MRSA and antibiotic-resistant S. aureus. Among the fractions tested, the chloroform fraction showed the highest antibacterial activity against MRSA and antibiotic-resistant S. aureus. The methanol-soluble extract of Glycyrrhizae Radix minimal inhibitory concentrations (MICs) against MRSA and antibiotics-resistant S. aureus were $5{\;}mg/m{\ell}$ in both. The methanol-soluble extract of Glycyrrhizae Radix was separated using thin-layer chromatography and detected with UV -detector. Further study should be carried out to identify which effects cell growth inhibition of MRSA and antibiotics-resistant S. aureus.

• Journal of Korean Society on Water Environment
• /
• v.22 no.3
• /
• pp.527-533
• /
• 2006

Tetracycline is one of the mostly used antibiotics around the world. The purpose of this study was to evaluate the fate of two different types of tetracycline resistant bacteria in biological wastewater treatment plants. Tetracycline resistant enterics and heterotrophic bacteria were monitored under two different lab-scale experimental conditions. Tetracycline resistant enteric bacteria showed the lower percentages of total enteric bacteria and net specific growth rate in the monitored activated sludge system as compared to tetracycline resistant heterotrophic bacteria. Therefore, total enterics, potentially E.coli, might not be the best indicator microorganism for evaluating the antibiotic resistant bacteria in biological wastewater treatment plant.