• BMB Reports
• /
• 제31권3호
• /
• pp.296-302
• /
• 1998

A potentiometric flow injection biosensor for the analysis of anti-cholinesterases (anti-ChEs), based on inhibition of enzyme activity, was developed. The sensor system consists of a reactor with acetylcholinesterase (AChE) immobilized on controlled pore glass and a detector with an $H^{+}-selective$ PVC-based membrane electrode. The principle of the analysis is based on the fact that the degree of inhibition of AChE by an anti-ChE is dependent on the concentration of the anti-ChE in contact with AChE. The sensor system was optimized by changing systematically the operating parameters of the sensor to evaluate the effect of the changes on sensor response to ACh. The optimized biosensor was applied to the analysis of paraoxon, an organophosphorus pesticide. Treatment of the inhibited enzyme with pyridine-2-aldoxime fully restored the enzyme activity allowing repeated use of the sensor.

• 한국전산유체공학회지
• /
• 제17권2호
• /
• pp.107-112
• /
• 2012

We explored the dynamic motions and the lateral equilibrium positions of an elastic capsule in channel flow at moderate Reynolds number varying Re, aspect ratio, size ratio, membrane stretching and bending coefficient. The transition of tank-treading/swinging to tumbling motion was observed in the simulations and the transition of dynamic motions for capsules resulted in different trend of the variation in the lateral equilibrium positions. Though other conditions were similar, the capsule with tumbling motion migrated closer to the wall than that with tank-treading motion.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 추계학술대회 논문집
• /
• pp.19-22
• /
• 2007

In this study, we investigated operating characteristics of natural gas fuel processor for polymer electrolyte membrane fuel cells (PEMFCs). The fuel processor consists of a natural gas reformer, a water-gas shift reactor, a heat-exchanger and a burner, in which the overall integrated volume is exactly(exceptionally) small, namely, about 10L except outer insulation. The producted hydrogen is $1Nm^3/hr$ and the maximum thermal efficiency is ${\sim}76%$(low heating value) at full operating load. A compact and highly efficient $1Nm^3/hr$ class natural gas fuel processor was developed at UNISON is an advantage for application in residential PEMFCs co-generation systems.

• Journal of Microbiology and Biotechnology
• /
• 제14권2호
• /
• pp.317-323
• /
• 2004

This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides against three Gram-negative bacteria and five Gram-positive bacteria. Nine classes of hetero-chitosan oligosaccharides consisted of partially deacetylated chitosans; 90％, 75％, and 50％ deacetylated chitosans. Based on molecular weight, they were prepared using an ultrafiltration membrane reactor system. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity as compared with the 90％ and 50％ deacetylated chitosan, and the activity was dependent on their molecular weights. It was apparent that the growth of Gram-negative bacteria is less inhibited in the presence of the heterochitosans and their oligosaccharides than Gram-positive bacteria. These results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides depend on the degree of deacetylation, and their molecular weights.

• Journal of Microbiology and Biotechnology
• /
• 제14권1호
• /
• pp.41-47
• /
• 2004

This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides on the halophilic bacterium, Vibrio parahaemolyticus. Nine classes of hetero-chitosan oligosaccharides were prepared based on their molecular weights, using an ultrafiltration membrane reactor system with chitosanase and celluase, from partially different deacetylated chitosans, 90%, 75%, and 50% deacetylated chitosan, respectively. Thirty-two strains of V. parahaemolyticus were isolated from various marine organisms such as shellfish, shrimps, octopus, and seabirds. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity. The minimal inhibitory concentration (MIC) was 0.5 mg/ml on 14 strains of V. parahaemolyticus, and MIC of the rest strains (18 strains) was 1.0 mg/ml. In addition, MIC of most hetero-chitosan oligosaccharides was 8.0 mg/ml. The results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides against V. parahaemolyticus depend on the degree of deacetylation, their molecular weights, and strains tested.

• 한국어업기술학회:학술대회논문집
• /
• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
• /
• pp.147-148
• /
• 2001

Many people living in Asia countries, particularly Korea, Japan and China, have consumed very widely fresh seafood products, such as shrimps, oysters, mussels and other marine invertebrates and fishes, without any heating or cooking. A variety of Vibrio spp., including V. parahaemolyticus, V. cholera. V. vulnificus, and V. fluvialis, lives in these seafoods and cause great problems associated with human disease. A strong antimicrobial agent to effectively inhibit the growth of these pathogenic bacteria in in vivo or in vitro is urgently need for preventing fish and human diseases. (omitted)

• 한국환경과학회지
• /
• 제12권10호
• /
• pp.1095-1100
• /
• 2003

In this study, it was performed using submerged nonwoven bioreactor(SNBR) for removal of organic matter, nitrogen and phosphate under different aeration intervals(intermittent aeration). We applied the SNBR at the cheap nonwoven fiber module instead of the expensive membrane. The SUBR was mainly made up of an activated sludge reactor and a transverse flow nonwoven module, with an innovative configuration being in application between them. In case of sewage, the aeration conditions experimented consist of continuous aeration and 60min/60min, 120min/60min, 120min/120min of aeration/nonaeration time intervals, respectively. In case of landfill leachate, the intermittent aeration condition was 120min/120min at aeration/nonaeration. Consequently, a high COD removal rate (about 94%) was achieved in sewage and leachate. Although nutrient removal rate was relatively high without any additional chemicals.

• 한국수소및신에너지학회논문집
• /
• 제27권3호
• /
• pp.264-269
• /
• 2016

A simple dry chemical approach was developed in order to load palladium (Pd) as a promoter on Pt/gas diffusion electrode (GDE) for polymer electrolyte membrane fuel cell (PEMFC). Palladium(II) bis (acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into Pt/GDE and then reduced to Pd nanoparticles simultaneously without any reducing agent and any solvent in a glass reactor of $N_2$ atmosphere at $180^{\circ}C$ for 3, 5 and 15 min. Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• 한국환경과학회지
• /
• 제28권10호
• /
• pp.899-905
• /
• 2019

Recently, an innovative method for wastewater treatment and nutrient removal was developed by combining the sequence batch reactor and membrane bioreactor to overcome pollution caused by shipboard sewage. This system is a modified form of the activated sludge process and involves repeated cycles of mixing and aeration. In the present study, the bacterial diversity and dominant microbial community in this wastewater treatment system were studied using the MACROGEN next generation sequencing technique. A high diversity of bacteria was observed in anaerobic and aerobic bioreactors, with approximately 486 species. Microbial diversity and the presence of beneficial species are crucial for an effective biological shipboard wastewater treatment system. The Arcobacter genus was dominant in the anaerobic tank, which mainly contained Arcobacter lanthieri (8.24%), followed by Acinetobacter jahnsonii (5.81%). However, the dominant bacterial species in the aerobic bioreactor were Terrimonas lutea (7.24%) and Rubrivivax gelatinosus (4.95%).

• 상하수도학회지
• /
• 제23권5호
• /
• pp.527-537
• /
• 2009

Three sets of parallel MBRs (reactor No.1, reactor No.2, reactor No.3) maintaining an MLSS of 4,000 mg/L, 6,000 mg/L and 8,000 mg/L, respectively, were operated to investigate the effect of various HRTs and DO concentration of MBRs on the removal efficiency of organic matters and nitrogen. The HRTs were operated on 4 hr, 6 hr, 8 hr. DO concentrations were ranged 1.5~2.0 mg/L and 0.5~1.0 mg/L respectively on each HRT conditions. MBR was divided into an aerated part and non-aerated part by baffle placed under the water. DO concentrations were controlled by altering the position of baffle. In terms of TSS and CODCr, all systems had a similar level of the removal under varied HRTs and MLSS. TSS removal efficiency was more than 99% and CODCr removal was ranged 94~97% under all conditions. Under the same condition on the HRT and MLSS concentrations, DO concentrations did not affect the organic removal efficiency. On the nitrification efficiency, with high DO concentration, as HRT or MLSS increased, the slight increment of nitrification efficiency was observed. However, under the low DO concentration, increase of MLSS and HRT resulted in larger increase of the nitrification efficiency. At the same HRT and MLSS, the nitrification efficiency increased greatly with up to 16% as DO increased. When the HRT increased from 4hr to 8hr, the denitrification efficiency slightly increased under most of conditions. However, the increase of MLSS resulted in about 19~39% denitrification efficiency increment. MLSS concentrations showed great effect on the denitrification. The increase of the DO concentration at the same HRT and MLSS resulted in decrease of denitrification efficiency with up to 27%. In all systems, the denitrification efficiency had more influence on the TN removal efficiency than nitrification efficiency. So, MLSS concentration has greater effect on the TN removal than HRT and DO. The TN removal efficiency increased as MLSS increased with up to 37%. As a result, the highest TN removal efficiency was observed 79.0% at the condition showed the highest denitrification efficiency that DO of 0.5~1.0 mg/L, an HRT of 8 hr, and 8,000 mg/L of MLSS concentration were maintained.