• 상하수도학회지
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• 제19권6호
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• pp.800-808
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• 2005

It is required to propose an alternatives for appropriate sludge treatment owing to persistent construction of sewage treatment plant and increase of sewage sludge quantity. In order to treat sludge more efficiently, the methods which reduce the cost of sludge treatment have been studied such as sludge reduction and conditioning. Especially ozone treatment reduces solid quantity and improves separation of solid-liquid at the same time. Therefore ozone treatment have a positive effect on reduction and stabilization of sludge. So, this study applied ozone to sewage sludge and induced cell destruction of sludge. By comparing with the correlation between thickening and dewatering, and evaluating moisture content and solubilization of cake, this study verificates the effect of process improvement for ozone pre-treatment. In J-STP case, according to ozone dose solid flux increased about 12 times from $1kg/m^2{\cdot}h$ to $12kg/m^2{\cdot}h$. Also this plant were capable to shorten thickening time from 40 minutes to 6~7 minutes. Thus it is expected to reduce volume and retention time of thickener. On pH effect factor, dewatering at pH4 was more than at pH11, $3.05{\times}10^{11}$ and $3.82{\times}10^{11}(m/kg)$. But effect of pH was analogous to ozone, $2.81{\times}10^{11}(m/kg)$. The effect of pH on thickening was similar to law sludge, $0.68(kg/m^2{\cdot}h)$, and the effect of ozone injection on thickening was the biggest, $3.45(kg/m^2{\cdot}h)$. The COD solubilization rate improved from about 5 to 30%. So it is judged that we are able to utilize most solubilized sludge to another sewage treatment plants.

• Asian Pacific Journal of Cancer Prevention
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• 제14권8호
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• pp.4853-4858
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• 2013

Objectives: To investigate whether hypoxia has an effect on regulation of multidrug resistance (MDR) to chemotherapeutic drugs in laryngeal carcinoma cells and explore the role of hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$). Methods: Laryngeal cancer cells were cultured under normoxic and hypoxic conditions. The sensitivity of the cells to multiple drugs and levels of apoptosis induced by paclitaxel were determined by MTT assay and annexin-V/propidium iodide staining analysis, respectively. HIF-$1{\alpha}$ expression was blocked by RNA interference. The expression of HIF-$1{\alpha}$ gene was detected by real-time quantitative RT-PCR and Western blotting. The value of fluorescence intensity of intracellular adriamycin accumulation and retention in cells was evaluated by flow cytometry. Results: The sensitivity to multiple chemotherapy agents and induction of apoptosis by paclitaxel could be reduced by hypoxia (P<0.05). A the same time, the adriamycin releasing index of cells was increased (P<0.05). However, resistance acquisition subject to hypoxia in vitro was suppressed by down-regulating HIF-$1{\alpha}$ expression. Conclusion: HIF-$1{\alpha}$ could be considered as a key regulator for mediating hypoxia-induced MDR in laryngeal cancer cells via inhibition of drug-induced apoptosis and decrease in intracellular drug accumulation.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.436-443
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• 2007

Anaerobic reductive dehalogenation of perchloroethene (PCE) was studied with lactate as the electron donor in a continuously stirred tank reactor (CSTR) inoculated with a mixed culture previously shown to dehalogenate vinyl chloride (VC). cis-1,2- dichloroethene (cDCE) was the dominant intermediate at relatively long cell retention times (>56 days) and the electron acceptor to electron donor molar ratio (PCE:lactate) of 1:2. cDCE was transformed to VC completely at the PCE to lactate molar ratio of 1:4, and the final products of PCE dehalogenation were VC (80%) and ethene (20%). VC dehalogenation was inhibited by cDCE dehalogenation. Propionate produced from the fermentation of lactate might be used as electron donor for the dehalogenation. Batch experiments were performed to evaluate the effects of increased hydrogen, VC, and trichloroethene (TCE) on VC dehalogenation which is the rate-limiting step in PCE dehalogenation The addition of TCE increased the VC dehalogenaiton rate more than an increase in the $H_2$ concentration, which suggests that the introduction of TCE induces the production of an enzyme that can comtabolize VC.

• 한국식품영양과학회지
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• 제21권5호
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• pp.573-579
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• 1992

숙시닐화가 균체 단백질(Aspergillus fumigatus)의 여러가지 기능적 특성에 미치는 영향을 검토하였다. 균체 단백질은 succinic anhydride 2.5와 10% 첨가에 20.7 과 85.3%가 숙시닐화되었다. 숙시닐화된 균체 단백질은 흡광도, 핵산 및 탄수화물의 양은 감소하였으나 단백질소, 단백질 추출율은 증가되었다. 숙시닐화된 균체 단백질의 질소용해도는 milk casein과 soy flour 보다 32와 51% 증가되었다. 유화활성도와 유화 안정성은 균체 단백질의 숙시닐화 비율에 따라서 증가 되었으며, 80% 숙시닐화된 균체 단백질은 약 8.4배 증가율을 나타내어 숙시닐화를 증가시킴에 따라 유화활성도와 유화안정성이 증가 되었다. 숙시닐화 시킨 균체 단백질은 숙시닐화 시키지 않는 균체 단백질, milk casein 및 soy flour에 비하여 향상된 기능적 특성을 나타내었다.

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.459-464
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• 2016

본 연구에서는 리튬이온 전지용 실리콘 음극소재의 사이클 안정성 및 율속 특성 향상을 위해 다공성 실리콘/탄소 복합소재의 전기화학적 특성을 조사하였다. 나노 실리카 제조는 스토버 방법을 사용하고 교반 속도, 교반 온도 및 $NH_3$/TEOS 비율을 조절 하여 100~500 nm 크기의 구형 실리카를 합성하였다. 구형 나노 실리카의 마그네슘 열환원과 산처리 과정을 통해 다공성 실리콘을 얻고, 제조된 다공성 실리콘에 Phenolic resin을 탄소전구체로 사용하여 최종적으로 다공성 실리콘/탄소 활물질을 합성하였다. 또한 $LiPF_6$ (EC:DMC:EMC=1:1:1 vol%) 전해액에서 다공성 실리콘/탄소 음극소재의 충 방전, 순환전압 전류, 임피던스 테스트 등의 전기화학적 특성을 조사 하였다. 다공성 실리콘/탄소 복합소재의 음극활물질로서 코인 전지의 성능을 조사한 결과 초기용량 및 40사이클 용량 보존율은 각각 2,006 mAh/g, 55.4%를 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1439-1446
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• 2009

Isocarbophos is a widely used organophosphorus insecticide that has caused environmental pollution in many areas. However, degradation of isocarbophos by pure cultures has not been extensively studied, and the degradation pathway has not been determined. In this paper, a highly effective isocarbophos-degrading strain, scl-2, was isolated from isocarbophos-polluted soil. The strain scl-2 was preliminarily identified as Arthrobacter sp. based on its morphological, physiological, and biochemical properties, as well as 16S rDNA analysis. The strain scl-2 could utilize isocarbophos as its sole source of carbon and phosphorus for growth. One hundred mg/l isocarbophos could be degraded to a non detectable level in 18 h by scl-2 in cell culture, and isofenphos-methyl, profenofos, and phosmet could also be degraded. During the degradation of isocarbophos, the metabolites isopropyl salicylate, salicylate, and gentisate were detected and identified based on MS/MS analysis and their retention times in HPLC. Transformation of gentisate to pyruvate and fumarate via maleylpyruvate and fumarylpyruvate was detected by assaying for the activities of gentisate 1,2-dioxygenase (GDO) and maleylpyruvate isomerase. Therefore, we have identified the degradation pathway of isocarbophos in Arthrobacter sp. scl-2 for the first time. This study highlights an important potential use of the strain scl-2 for the cleanup of environmental contamination by isocarbophos and presents a mechanism of isocarbophos metabolism.

• Journal of the Korean Wood Science and Technology
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• 제25권1호
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• pp.15-22
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• 1997

The effectiveness of presteaming for improving CCA treatability on refractory Japanese larch heartwood was investigated in this study. Presteaming was effective on improving treatability, and the extent of improvement was dependent on moisture contents of wood specimen and steaming conditions. Green wood showed higher average value in both preservative retention and penetration than dry wood, and steaming under pressure conditions also had higher treatability than steaming at atmospheric conditions. The degree of improvement for treatability was increased with the extension of steaming period. Treatability of dry wood pres teamed under pressure conditions more than 6 hours and green wood for 3 hours was similar to that enhanced by conventional incising. Presteaming green wood under pressure conditions more than 6 hours was more effective than conventional incising in improvement of CCA treatability, and resultant treatability satisfied a minimum value required for CCA-treated wood for being used at the regions of hazard class H3 and H4. In addition, an improvement of treatability by presteaming was due to an increase in permeability resulted from the degradation of hemicelluloses within aspirated pit membrane and cell wall, not the removal of extractives from pit membrane. The reduction in strength, measured as longitudinal compressive strength, due to pres teaming was related with the degradation of hemicelluloses, and was increased as steaming conditions were severe. The degree of strength reduction associated with presteaming treatment to obtain required treatability could be quantified from the relatively good relation between the increase in treatability and the decrease in strength.

• KSBB Journal
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• 제18권6호
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• pp.500-505
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• 2003

재조합 대장균에서 내포체 형태로 발현시킨 LK68을 생물학적 활성을 가진 native한 단백질로 재생시키기 위해서 PBA 크로마토그래피와 EBA 크로마토그래피를 이용한 고체상 재접힘을 수행하였다. 내포체와 세포파쇄액을 시작물질로 하여 재접힘 공정을 수행하였으며 총 단백질 회수율과 재접힘 수율을 비교한 결과, EBA 공정이 기존의 액상 재접힘이나 PBA를 이용한 재접힘 공정에 비하여 우수함을 확인하였다. 또한 Iysine binding, RP-HPLC, SEC-HPLC, Ellman method 등을 사용하여 분석한 결과 재접힘된 LK68이 native LK68와 동등함을 확인하였다. 본 연구를 통해 EBA 크로마토그래피를 이용한 재접힘 방법은 재접힘 단계의 수율을 향상시킬 뿐 아니라 공정 단계, 시간 등을 감소시켜 공정 성능을 전체적으로 향상시킬 수 있음을 제시하였다.

• Korean Chemical Engineering Research
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• 제52권1호
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• pp.98-105
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• 2014

라이소자임은 용균 작용, 조직 회복 과정의 촉진 등의 작용을 하며 난백 중에 0.3% 함유되어 있다. 난백에서 라이소자임을 분리하는 방법으로 친화성 크로마토그래피, 이온교환크로마토그래피, 한외여과법 등이 있는데 이 중 이온교환크로마토그래피가 가장 많이 사용된다. 라이소자임을 양이온 젤이 충전된 유리 칼럼에서 분리 정제할 때 최적의 pH와 온도 조건을 찾는 것을 실험 목표로 하고, ASPEN Chromatography 전산 모사의 결과와 비교하였다. 실험에 사용되는 완충용액은 인산완충용액이었고 pH를 5~8로 변화를 주어 상온에서 실험하였고, 가장 분리가 잘 이루어진 pH에서 온도를 $5^{\circ}C$ 간격으로 $25{\sim}40^{\circ}C$로 변화시켜 실험하였다. RP-HPLC (Reversed phase High Performance Liquid Chromatography) 분석을 통해 라이소자임의 체류 시간을 확인하였고, OriginPro 8을 이용해 용출 단계에서 크로마토그램의 면적을 비교하여 라이소자임의 양을 정량분석하였다. 결과를 분석한 결과, pH 5일 때, 온도가 $25^{\circ}C$에서 가장 많은 양의 라이소자임이 분리되었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권10호
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• pp.438-442
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• 2005

Si nanocrystal (Si NC) memory device has several advantages such as better retention, lower operating voltage, reduced punch-through and consequently a smaller cell area, suppressed leakage current. However, the physical and electrical reasons for this behavior are not completely understood but could be related to interface states of Si NCs. In order to find out this effect, we characterized electrical properties of Si NCs embedded in a SiO$_{2}$ layer by scanning probe microscopy (SPM). The Si NCs were generated by the laser ablation method with compressed Si powder and followed by a sharpening oxidation. In this step Si NCs are capped with a thin oxide layer with the thickness of 1$\~$2 nm for isolation and the size control. The size of 51 NCs is in the range of 10$\~$50 m and the density around 10$^{11}$/cm$^{2}$ It also affects the interface states of Si NCs, resulting in the change of electrical properties. Using a conducting tip, the charge was injected directly into each Si NC, and the image contrast change and dC/dV curve shift due to the trapped charges were monitored. The results were compared with C-V characteristics of the conventional MOS capacitor structure.