• BMB Reports
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• 제41권1호
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• pp.11-22
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• 2008

Apoptosis (programmed cell death) is a cellular self-destruction mechanism that is essential for a variety of biological events, such as developmental sculpturing, tissue homeostasis, and the removal of unwanted cells. Mitochondria play a crucial role in regulating cell death. $Ca^{2+}$ has long been recognized as a participant in apoptotic pathways. Mitochondria are known to modulate and synchronize $Ca^{2+}$ signaling. Massive accumulation of $Ca^{2+}$ in the mitochondria leads to apoptosis. The $Ca^{2+}$ dynamics of ER and mitochondria appear to be modulated by the Bcl-2 family proteins, key factors involved in apoptosis. The number and morphology of mitochondria are precisely controlled through mitochondrial fusion and fission process by numerous mitochondria-shaping proteins. Mitochondrial fission accompanies apoptotic cell death and appears to be important for progression of the apoptotic pathway. Here, we highlight and discuss the role of mitochondrial calcium handling and mitochondrial fusion and fission machinery in apoptosis.

• Journal of Korean Neurosurgical Society
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• 제52권4호
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• pp.353-358
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• 2012

Objective : The purpose of this study was to determine the efficacy of bone cement-augmented short segment fixation using percutaneous screws for thoracolumbar burst fractures in a background of severe osteoporosis. Methods : Sixteen patients with a single-level thoracolumbar burst fracture (T11-L2) accompanying severe osteoporosis treated from January 2008 to November 2009 were prospectively analyzed. Surgical procedures included postural reduction for 3 days and bone cement augmented percutaneous screw fixation at the fracture level and at adjacent levels without bone fusion. Due to the possibility of implant failure, patients underwent implant removal 12 months after screw fixation. Imaging and clinical findings, including involved vertebral levels, local kyphosis, canal encroachment, and complications were analyzed. Results : Prior to surgery, mean pain score (visual analogue scale) was 8.2 and this decreased to a mean of 2.2 at 12 months after screw fixation. None of the patients complained of pain worsening during the 6 months following implant removal. The percentage of canal compromise at the fractured level improved from a mean of 41.0% to 18.4% at 12 months after surgery. Mean kyphotic angle was improved significantly from $19.8^{\circ}$ before surgery to 7.8 at 12 months after screw fixation. Canal compromise and kyphotic angle improvements were maintained at 6 months after implant removal. No significant neurological deterioration or complications occurred after screw removal in any patient. Conclusion : Bone cement augmented short segment fixation using a percutaneous system can be an alternative to the traditional open technique for the management of selected thoracolumbar burst fractures accompanied by severe osteoporosis.

• 한국동물학회지
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• 제38권4호
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• pp.483-489
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• 1995

많은 세포와 조직에서 분화 조절물질로 알려져 있는 비타민 A의 대사산물인 rectinoic acid(RA)가 배양 계배 근원세포의 성장과 분화에 미치는 영향을 조사하였다. RA가 처리된 세포는 그 농도가 증가함에 따라 융합 억제 효과도 증가함을 보였고, 배양액으로부터 RA를 제거해 주면 근원세포의 융합이 재개되는 것으로 보아, RA는 근원세포의 융합을 가역적으로 억제함을 알 수 있었다. 그러나 이미 최종 분화 단계에 들어선 세포에서는 융합 억제 효과를 보이지 않아, RA의 효과는 분화 단계에 따라 특이적으로 작용함을 보여준다. 융합 억제 효과에도 불구하고, RA는 근원세포의 융합 전단계인 방추형으로 신장하는 것과 그들이 가상의 축을 따라 배열하는 데는 영향을 주지 않았다. 또한 세포의 증식과 creatine kimase, tropomyosin과 같은 근특이 단백질의 축적에도 큰 영향을 주지 않았다. 한편, 근원세포는 융합하기 전에 필수적으로 fibronectin의 감소를 억제함을 알 수 있었다. 이상의 결과로 RA는 배양 근원세포의 융합만을 특이하게 억제하는 물질이며, 그 작용은 fibronectin의 감소를 방해하는 것과 밀접한 관계가 있는 것으로 사료된다.

• Journal of Electrochemical Science and Technology
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• 제8권2호
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• pp.124-132
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• 2017

The performance of electrolytic processes using copper and catalyzed electrodes for enhanced nutrient removal with various catalyzers and combinations of electrodes was evaluated. The catalyzed electrodes removed more ammonia nitrogen than the copper electrode, but higher ammonia removal was achieved using a Pt/Ti anode. On the other hand, electrolysis using the Pt/Cu anode consumed less energy and cost less. During electroreduction, nitrate was better removed by a pair of copper electrodes than by the catalyzed electrodes. During electrolysis of synthetic wastewater, ammonia removal not only increased owing to direct oxidation at the anode, but was also influenced by indirect oxidation at the cathode. Platinum-coated copper and titanium cathodes actively produced oxidizers and thus removed more ammonia than a pure metal cathode. Although phosphorus was removable irrespective of the type of catalyzer, electrocoagulation using the copper electrode achieved complete removal of phosphorus in a period of less than 10 min.

• Journal of Electrochemical Science and Technology
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• 제8권1호
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• pp.35-42
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• 2017

In this study, the effect of electrolyte addition on the removal of organics and nutrients in electrochemical wastewater using a copper electrode, and the characteristics of the by-product of electrolysis were investigated. The removal of organics increased significantly as shorter reaction times upon the addition of chloride ion, and most of the electrolysis reaction was completed within 20 min. The reaction rate gradually increased in proportion to the $Cl^-$/COD ratio, whereas the highest removed mass of organic matter per mass of added electrolyte was observed at a $Cl^-$/COD ratio of 1. After the addition of electrolyte, significant removal of ammoniacal nitrogen was observed as a result of the enhanced generation of oxidizers such as hypochlorite. Excellent phosphorus removal was also achieved in a very short reaction time (within 2 min) by electro-coagulation. As the electrolysis progressed, the amount of by-product increased gradually, whereas a decrease of sludge volume index was observed after the addition of electrolyte. This indicated that the settling performance of the by-products was better, and their removal would be easily achieved.

• Nuclear Engineering and Technology
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• 제40권6호
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• pp.467-476
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• 2008

To keep the superconducting (SC) magnet coils of KSTAR at proper operating conditions, not only the coils but also other cold components, such as thermal shields (TS), magnet structures, SC bus-lines (BL), and current leads (CL) must be maintained at their respective cryogenic temperatures. A helium refrigeration system (RRS) with an exergetic equivalent cooling power of 9 kW at 4.5 K without liquid nitrogen ($LN_2$) pre-cooling has been manufactured and installed. The main components of the KST AR helium refrigeration system (HRS) can be classified into the warm compression system (WCS) and the cryogenic devices according to the operating temperature levels. The process helium is compressed from 1 bar to 22 bar passing through the WCS and is supplied to cryogenic devices. The main components of cryogenic devices are consist of cold box (C/B) and distribution box (D/B). The C/B cool-down and make the various cryogenic helium for the KSTAR Tokamak and the various cryogenic helium is distributed by the D/B as per the KSTAR requirement. In this proceeding, we will present the commissioning results of the KSTAR HRS. Circuits which can simulate the thermal loads and pressure drops corresponding to the cooling channels of each cold component of KSTAR have been integrated into the helium distribution system of the HRS. Using those circuits, the performance and the capability of the HRS, to fulfill the mission of establishing the appropriate operating condition for the KSTAR SC magnet coils, have been successfully demonstrated.

• Carbon letters
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• 제15권2호
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• pp.136-141
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• 2014

Three dimensional self-assembled graphene hydrogels were easily fabricated by electron beam irradiation (EBI) using an aqueous solution of wool/poly(vinyl alcohol) and graphene oxide (GO). After exposure to various levels of EBI radiation, the highly porous, self-assembled, wool-based graphene hydrogels were characterized using scanning electron microscopy and Fourier-transform infrared spectroscopy; to determine the gel fraction, degree of swelling, gel strength, kinetics-of-swelling analyses and removal of hexavalent chromium (Cr(VI)) from the aqueous solution. X-ray diffraction results confirmed that EBI played a significantly important role in reducing GO to graphene. The adsorption equilibrium of Cr(VI) was reached within 80 min and the adsorption capacity was dramatically increased as the acidity of the initial solution was decreased from pH 5 to 2. Changes in ionic strength did not exert much effect on the adsorption behavior.

• Journal of Korean Neurosurgical Society
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• 제29권3호
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• pp.360-364
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• 2000

Objective : To investigate the prognostic factors associated with outcome in patients with ossification of posterior longitudinal ligament. Method : During the past 4 years, we have operated on 35 patients with cervical OPLL. Anterior cervical decompression(total or subtotal corpectomy, discectomy, and removal of the OPLL) and interbody fusion with iliac bone were performed in all patients. Results : Eight cases(22.9%) were continuous type, 11(31.4%) segmental, 13(37.1%) Mixed, and 3(8.6%) localized type. Thirty-two patients(91.4%) showed an excellent or good results. Conclusion : These results indicate that surgical treatment should be considerated in case of clinical grading higher than II and the surgical outcome is worse when duration of preoperative symptom is longer and when percentage of spinal narrowing is higher. Anterior cervical decompression and interbody fusion seems to be a better method in patients with lesions limited to one or two level. Age at surgery did not significantly affect the outcom.

• Journal of Microbiology and Biotechnology
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• 제33권11호
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• pp.1513-1520
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• 2023

Kex2 protease (Kex2p) is a membrane-bound serine protease responsible for the proteolytic maturation of various secretory proteins by cleaving after dibasic residues in the late Golgi network. In this study, we present an application of Kex2p as an alternative endoprotease for the in vitro processing of recombinant fusion proteins produced by the yeast Saccharomyces cerevisiae. The proteins were expressed with a fusion partner connected by a Kex2p cleavage sequence for enhanced expression and easy purification. To avoid in vivo processing of fusion proteins by Kex2p during secretion and to guarantee efficient removal of the fusion partners by in vitro Kex2p processing, P₁', P₂', P₄, and P₃ sites of Kex2p cleavage sites were elaborately manipulated. The general use of Kex2p in recombinant protein production was confirmed using several recombinant proteins.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.595-603
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• 2012

국제핵융합실험로(ITER)가 2019년까지 7개국의 공동개발사업으로 건설될 예정이다. ITER의 핵융합연료주기는 핵융합진공용기, 삼중수소 플랜트, 연료공급부로 구성되어 있다. 이중에서 삼중수소 플랜트는 핵융합연료주기를 위한 중 수소와 삼중수소의 저장, 공급, 분리, 제거, 회수 등의 기능을 제공한다. 삼중수소 플랜트는 외부에서 중수소와 삼중수소를 공급받아 저장 공급하는 SDS, 토카막배출처리의 TEP, 수소동위원소 분리의 ISS, 삼중수소수 및 대기 처리의 WDS ADS, 정성 정량분석의 ANS 등으로 구성된다. 이 논문에서는 삼중수소 플랜트를 구성하는 주요 공정에 대한 기능 및 설계요건을 기술하였다. 한국은 SDS 개발에 참여하고 있으며 월성원전 삼중수소 제거설비(WTRF) 건설 및 운전경험을 통해 WDS 대한 기술을 일부 확보하였다. 향후 ISS 및 TEP에 대한 기술확보를 위한 여러 분야에서의 참여 확대를 기대하고 있다.