• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.301-305
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• 2007

The performance of polymer electrolyte membrane fuel cell could be decreased due to coolant leaked from connection part. Micro pump was used to put small amount of coolant and investigate the effect on fuel cell. The stoichiometric ratio of hydrogen/air was 1.5/2.0, both side of gas was fully humidified, and current density of $400mA/cm^2$ was used as standard condition in this experiment. Constant current method was used to check performance recovery from coolant effect in 3 cell stack. The performance was recovered when coolant was injected in cathode side. On the other hand, the performance was not recovered when coolant was injected in anode side. Ethylene glycol could be converted to CO in oxidation process and cause poisoning effect on platinum catalyst or be adhered on GDL and cause gas diffusion block effect resulting performance decrease. Water with nitrogen gas was supplied in anode side to check performance recovery. Polarization curve, cyclic voltammetry, electrochemical impedance spectroscopy was used to check performance, and gas chromatography was used to check coolant concentration. Constant current method was not enough in full recovery of performance. However, water injection method was proved good method in full recovery of performance.

• Journal of Microbiology and Biotechnology
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• v.6 no.4
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• pp.225-231
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• 1996

The production of recombinant proteins in Escherichia coli often leads to the formation of an intracellular inclusion body. Key process steps that can determine the economics of large-scale protein production from inclusion bodies are fermentation, inclusion body recovery, and protein refolding. Compared with protein refolding and fermentation, inclusion body recovery has received scant research attention. Nevertheless, it can control the final product yield and hence process cost for some products. Optimal separation of inclusion bodies and cell debris can also aid subsequent operations by removing contaminant particulates that foul chromatographic resins and contain antigenic pyrogens. In this review, the properties of inclusion bodies and cellular debris are therefore examined. Attempts to optimise the centrifugal separation of inclusion bodies and debris are also discussed.

• Korean Journal of Environmental Biology
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• v.26 no.1
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• pp.1-7
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• 2008

A mathematical model for the synergistic interaction of physical and chemical environmental agents was suggested for quantitative prediction of irreversibly damaged cells after combined exposures. The model took into account the synergistic interaction of agents and was based on the supposition that additional effective damages responsible for the synergy are irreversible and originated from an interaction of ineffective sublesions. The experimental results regarding the irreversible component of radiation damage of diploid yeast cells simultaneous exposed to heat with ionizing radiation ($^{60}Co$) or UV light (254 nm) are presented. It was shown that the cell ability of the liquid holding recovery decreased with an increase in the temperature, at which the exposure was occurred. A good correspondence between experimental results and model prediction was demonstrated. The importance of the results obtained for the interpretation of the mechanism of synergistic interaction of various environmental factors is discussed.

• ALGAE
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• v.21 no.1
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• pp.109-124
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• 2006

Responses to various types of mechanically induced wounding were followed in the giant-celled Caulerpalean species, Derbesia tenuissima, using time-lapse video-microscopy. Gametophyte vesicle cells. Puncture wounding: the gametophyte cell seals the puncture in 5 min. This is followed by cycles of ruptures and sealing, ending with full recovery in 24 hrs. Cut wounding: the protoplast immediately retracts away from the wall and reforms an intact, deflated protoplast that expands to fill the original cell within 21 hrs. Crush wounding (internal). When retained within the cell wall many protoplast fragments condense, round up, and coalesce; the reconstituted protoplast expands until it attains complete recovery, filling the original cell shape in 12 hrs. Crush wounding (external). Protoplast fragments extruded from the crushed cell are more numerous and smaller taking longer to recover. Most fragments become spherical, transforming into small viable cells capable of reproduction in several days. Sporophyte filaments. Crush wounding creates many small fragments that initially condense, coalesce and then expand within the wall to restore a complete filament with normal cytoplasmic streaming within 5 hrs. Reproduction: gametophyte. Our culture isolates produce more females than males (30:1). Gametangia develop one day before discharge that occurs explosively (1/6 sec) at first morning light. The vesicle cell forms successive gametangia every 14 days. Sporophyte. Each sporangium develops on a lateral branch that becomes isolated by the creation of successive basal plugs. After cytoplasmic cleavage and differentiation the stephanokont spores are discharged. The spores settle quickly and germinate forming gametophyte cells.

• Journal of Pharmacopuncture
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• v.17 no.2
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• pp.18-26
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• 2014

Objectives: This study was performed to check for reversibility in the changes induced by a 13-week, repeated, dose toxicity test of Sweet Bee Venom (SBV) in Sprague-Dawley (SD) rats. Methods: Fifteen male and 15 female SD rats were treated with 0.28 mg/kg of SBV (high-dosage group) and the same numbers of male and female SD rats were treated with 0.2 mL/kg of normal saline (control group) for 13 weeks. We selected five male and five female SD rats from the high-dosage group and the same numbers of male and female SD rats from the control group, and we observed these rats for four weeks. We conducted body-weight measurements, ophthalmic examinations, urinalyses and hematology, biochemistry, histology tests. Results: (1) Hyperemia and movement disorder were observed in the 13-week, repeated, dose toxicity test, but these symptoms were not observed during the recovery period. (2) The rats in the high-dose group showed no significant changes in weight compared to the control group. (3) No significant differences in the ophthalmic parameters, urine analyses, complete blood cell counts (CBCs), and biochemistry were observed among the recovery groups. (4) No changes in organ weights were observed during the recovery period. (5) Histological examination of the thigh muscle indicated cell infiltration, inflammation, degeneration, necrosis of muscle fiber, and fibrosis during the treatment period, but these changes were not observed during the recovery period. The fatty liver change that was observed during the toxicity test was not observed during the recovery period. No other organ abnormalities were observed. Conclusion: The changes that occurred during the 13-week, repeated, dose toxicity test are reversible, and SBV can be safely used as a treatment modality.

• Nuclear Engineering and Technology
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• v.47 no.5
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• pp.588-595
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• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.321-324
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• 2002

In situ recovery of recombinant human granulocyte-macrophage colony stimulating factor (hGM-CSF) was performed in transgenic Nicotiana tabacum cell suspension cultures. Aqueous two-phase systems (ATPS) were used to utilize its biocompatibility. Transgenic plant cells could be grown up to 15.7 g/L in normal medium and 18.6 g/L in ATPS composed of 6% (w/w) polyethylene glycol (PEG) 20,000 and 10% (w/w) dextran 2,000,000. It was proved that the A TPS was not harmful to cell growth. In addition, It is expected to recover hGM-CSF simultaneously with cell growth. Using this method, maximum hGM-CSF concentration at 1.64 ng/mL was obtained on day 3.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.411-415
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• 2008

This paper presents on design factor considered in an altitude test cell facility to determine the best sizing to optimize exhaust diffuser pressure recovery and the exact cooling load required to be supplied under transient operation. Engine simulation was performed to analyse the exhaust gas temperature, exit mass flow rate, specific fuel consumption and exhaust velocity helpful in determining secondary mass air flow and the mixed air temperature entering the ejector. based on this, the amount of cooling load was deduced. It was found that improved pressure recovery reduces operational cost(air supply facility, cooling water).

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.107-114
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• 2017

The performance of polymer electrolyte membrane fuel cell (PEMFC) could be deteriorated when fuel contains contaminants such as carbon monoxide (CO) or hydrogen sulfide ($H_2S$). Generally, $H_2S$ is introduced in hydrogen by steam reforming of hydrocarbon which has mercaptan as odorant. $H_2S$ poisoning effect on PEMFC performance was examined on this study. Pure hydrogen injection, voltage cycling and water circulation methods were compared as performance recovery methods. The PEMFC performance was analyzed using electrochemical methods such as polarization curve, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Pure hydrogen injection and voltage cycling methods showed low recovery ratio, however, water circulation method showed high recovery ratio over 95%. Because anode was directly poisoned by $H_2S$, anode water circulation showed higher recovery ratio compared to the other methods. Water circulation method was developed to recover PEMFC performance from $H_2S$ poisoning. This method could contribute to PEMFC durability and commercialization.

• Resources Recycling
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• v.26 no.4
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• pp.88-94
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• 2017

The recovery of gold in cyclone type electrolytic cell was conducted from solution for stripping gold of PCB by cyanide. The electrolytic recovery behaviors of gold was investigated by reaction time and addition of electrolytic sodium hypochlorite (NaOCl) and gold plating additive (KG-120). Because the electrolysis generated NaOCl reacted with the cyanide in the leachate by alkaline chlorination, more than 99% of the cyanide was removed at a $NaOCl(g)/CN^-(g)$ ratio of 1.0. When NaOCl was added during the recovery of the gold from cyanide leachate in the cyclone electrolytic cell, the recovery of gold was 98% at the ratio of $NaOCl(g)/CN^-(g)$ from 0.5 to 2.5 in 480 minutes and decreased rapidly over the ratio of 3.0. Gold was recovered more than 99% by adding 1.5 and 4.5%(v/v) of KG-120 with NaOCl in 480 minutes. In particular, when the concentration of KG-120 was 3.5 and 4.5%(v/v), more than 96% of gold was recovered within 240 minutes and the initial recovery rate was relatively faster. The optimum concentration of KG-120 is 3.5%(v/v) considering the economic feasibility and efficiency.