• Journal of Chest Surgery
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• v.34 no.9
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• pp.653-661
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• 2001

Background: Retrograde cerebral perfusion(RCP) is one of the methods used for brain protection during aortic arch surgery. The author previously published the data, however, for the safety of it, there still remains many controversies. The author performed RCP and checked various parameters to clarify the possibility of early detection of cerebral injury. Material and Method: The author used pigs(Landrace species) weighing 25 to 30kg and performed RCP for 120 minutes. After weaning of cardiopulmonary bypass, we observed pigs for another 120 minutes. Rectal temperature, jugular venous oxygen saturation, central venous pressure were continuously monitored, and the hemodynamic values, histological changes, and serum levels of neuron-specific enolose(NSE) and S100$\beta$ protein were checked. Central venous pressure during RCP was maintained in the range of 20 to 25 mmHg. Result: Flow rates(ml/min) during RCP were 224.3$\pm$87.5(20min), 227.1$\pm$111.0(40min), 221.4$\pm$119.5(60min), 230.0$\pm$136.5(80min), 234.3$\pm$146.1(100min), and 184.3$\pm$50.5(120min). Serum levels of NSE did not increase after retrograde cerebral perfusion. Serum levels of S100$\beta$ protein(ng/ml) were 0.12$\pm$0.07(induction of anesthesia), 0.12$\pm$0.07(soon after CPB), 0.19$\pm$0.12(20min after CPB), 0.25$\pm$0.06(RCP 20min), 0.29$\pm$0.08(RCP 40min), 0.41$\pm$0.05(60min), 0.49$\pm$0.03(RCP 80min), 0.51$\pm$0.10(RCP 100min), 0.46$\pm$0.11(RCP 120min), 0.52$\pm$0.15(CPBoff 60min), 0.62$\pm$0.15(60min after rewarming), 0.76$\pm$0.17(CPBoff 30min), 0.81$\pm$0.20(CPBoff 60min), 0.84$\pm$0.23(CPBoff 90min) and 0.94$\pm$0.33(CPBoff 120min). The levels of S100$\beta$ after RCP were significantly higher than thosebefore RCP(p<0.05). The author could observe the mitochondrial swellings using transmission electron microscopy in neocortex, basal ganglia and hippocampus(CA1 region). Conclusion: The author observed the increase of serum S100$\beta$ after 120 minutes of RCP. The correlation between its level and brain injury is still unclear. The results should be reevaluated with longterm survival model also considering the confounding factors like cardiopulmonary bypass.

• Journal of Chest Surgery
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• v.41 no.4
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• pp.405-416
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• 2008

Background: Spinal cord ischemic injury during thoracic and thoracoabdominal aortic surgeries remains a potentially devastating outcome despite using various methods of protection. Neuronal voltage-dependent sodium channel antagonists are known to provide neuroprotection in cerebral ischemic models. This study was designed to compare the neuroprotective effects of phenytoin with those of hypothermia in a rabbit model of spinal cord ischemia. Material and Method: Spinal cord ischemia was induced in New Zealand white rabbits by means of infrarenal aortic cross clamping for 25 minutes. Four groups of 8 animals each were studied. The control group and the hypothermia group received retrograde infusion of saline only ($22^{\circ}C$, 2 mL/min); the normothermic phenytoin group and the hypothermicphenytoin group received retrograde infusion of 100 mg of phenytoin at different rectal temperatures ($39^{\circ}C$ and $37^{\circ}C$, respectively) during the ischemic period. The neurologic function was assessed at 24 and 72 hours after the operation with using the modified Tarlov criteria. The spinal cords were harvested after the final neurologic examination for histopathological examination to objectively quantify the amount of neuronal damage. Result: No major adverse effects were observed with the retrograde phenytoin infusion during the aortic ischemic period. All the control rabbits became severely paraplegic, Both the phenytoin group and the hypothermia group had a better neurological status than did the control group (p < 0.05). The typical morphological changes that are characteristic of neuronal necrosis in the gray matter of the control animals were demonstrated by means of the histopathological examination, whereas phenytoin or hypothermia prevented or attenuated these necrotic phenomena (p < 0.05). The number of motor neuron cells positive for TUNEL staining was significantly reduced, to a similar extent, in the rabbits treated with phenytoin or hypothermia. Phenytoin and hypothermia had some additive neuroprotective effect, but there was no statistical significance between the two on the neurological and histopathological analysis. Conclusion: The neurological and histopathological analysis consistently demonstrated that both phenytoin and hypothermia may afford significant spinal cord protection to a similar extent during spinal cord ischemia in rabbits, although no significant additive effects were noticed.

• Tuberculosis and Respiratory Diseases
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• v.66 no.3
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• pp.178-185
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• 2009

Background: Epigallocatechin-3-gallate (EGCG) is the major catechin in green tea, and has shown antiproliferative, antiangiogenic, antimetastatic and cell cycle pertubation activity in various tumor models. Hypoxia can be induced because angiogenesis is insufficient for highly proliferating cancer. Hypoxia-inducible factor-1$\alpha$ (HIF-1$\alpha$) and its downstream target, vascular endothelial growth factor (VEGF), are important for angiogenesis, tumor growth and metastasis. The aim of this study was to determine how hypoxia could cause changes in the cellular phenomena and microenvironment in a non-small cell culture system and to examine the effects of EGCG on a HIF-1$\alpha$ and VEGF in A549 cell line. Methods: A549 cells, a non-small cell lung cancer cell line, were cultured with DMEM and 10% fetal bovine serum. A decrease in oxygen tension was induced using a hypoxia microchamber and a $CO_2-N_2$ gas mixture. Gas analysis and a MTT assay were performed. The A549 cells were treated with EGCG (0, 12.5, 25, 50 ${\mu}mol/L$), and then examined by real-time-PCR analysis of HIF-1$\alpha$, VEGF, and $\beta$-actin mRNA. Results: Hypoxia reduced the proliferation of A549 cells from normoxic conditions. EGCG inhibited HIF-1$\alpha$ transcription in A549 cells in a dose-dependent manner. Compared to HIF-1$\alpha$, VEGF was not inhibited by EGCG. Conclusion: HIF-1$\alpha$ can be inhibited by EGCG. This suggests that targeting HIF-1$\alpha$ with a EGCG treatment may have therapeutic potential in non-small cell lung cancers.

• KSBB Journal
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• v.14 no.3
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• pp.309-314
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• 1999

In order to produce high concentration of sodium gluconate, optimization of the fermentation conditions, such as glucose concentration, inoculum size, dissolved oxygen concentration and glucose feeding method, was examined. When the glucose concentration was maintained in the range of 30∼50 g/L during the batch fermentation, glucose conversion yield and productivity were 92.2% and 6.0 g/L/hr, respectively. In the case of the low concentration below 30 g/L, the yield decreased by about 25%. As the inoculum size increased above 20%(w/v), lag phase was shortened but the productivity decreased. The dissolved oxygen level of 60∼70% was shown to be the threshold point for 75% of increase in the productivity of sodium gluconate. Finally, optimal glucose feeding rate was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and was determined using various feeding methods such as exponential feeding, feeding based on the average glucose consumption rate and on the oxygen uptake rate and etc. Our result shows that glucose feeding, based on the oxygen uptake rate is a very simple, efficient and robust method, especially when oxygen is consumed as a substrate for the bioconversion. Using the above glucose feeding strategy under the optimized condition, 255 g/L of sodium gluconate concentration, 12 g/L/hr of productivity and 95% of glucose conversion yield were achieved with A. niger ACM53.

• Journal of the Korean Arthroscopy Society
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• v.6 no.1
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• pp.21-24
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• 2002

Purpose : The purpose was to assess the result of arthroscopic management of the septic arthritis on the knee in compromised patients. Materials and Methods : Fourteen patients with septic knee were analyzed. The mean age was 55 years and the mean follow-up period was 14.6 months. Underlying diseases included 4 cases of diabetes, and history of direct acupuncture in 4 cases. Clinical stage of septic arthritis was judged by $G\ddot{a}chter's$ classification, which was determined by arthroscopic findings. After arthroscopic irrigation and debridement, we observed the results of laboratory data and improvement of clinical findings. Results : Causative organism was identified in 7 cases and no organism was detected in the remaining 7 cases. Stage I was 1, stage II 8, stage III 4, and stage IV 1, respectively. Eleven of 14 cases were improved by one stage operation. Two cases of stage III were recurred and additional arthroscopic management was done. In 1 case of stage IV, symptom was not improved and needed arthrotomy. The result was unsatisfactory in patients with stage III and IV. Serum erythrocyte sedimentation rate and C-reactive protein were normalized after 29.3 and 20.8 days following the operation, respectively. Clinical symptoms disappeared average 2 days following the operation. Conclusion : Arthroscopic management of acute septic arthritis of the knee would be an effective and satisfactory treatment modality in that its postoperative pain and complications are minimal, and it can be done with ease repeatedly.

• Journal of Global Scholars of Marketing Science
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• v.2
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• pp.17-37
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• 1998

중소기업간 협력 활동은 사업의 전체 혹은 일정 부분에 대하여 분업이나 협업의 관계를 맺는 공동사업의 형태로 나타난다. 기업간 연결의 강도에 따라 기업들간에 형성되는 분업과 협업의 관계를 시장형, 중간조직형, 위계조직형으로 구분할 때, 중소기업간 공동사업은 중간조직형에 속하는 일종의 기업간 네트워크라고 볼 수 있다. 물론 네트워크형의 협력관계를 추진하는 방식도 업무제휴, 지분제휴, 합작투자, 컨소시엄 등으로 다양하다. 그러나 완전한 자본적 통합에 따른 위계적 조직과는 달리 참여기업들이 독립성을 유지하면서, 네트워크 밖의 기업에 대해 경쟁우위를 확보하기 위해 형성한다는 공통점을 가지고 있다. 기업간 협력관계를 통해 참여 기업들이 얻을 수 있는 혜택에 관한 기존연구들은 크게 두 가지로 나누어 볼 수 있다. 하나는 기업의 생산함수를 중심으로 그 이점을 파악하는 것이고 다른 하나는 관계의 종류에 따라 기업간 거래관계를 관리하는 소위 거래비용의 효율성을 중심으로 혜택을 파악하는 접근방법이다. 전자의 접근방법을 따를 때, 기업간 협력의 근본 유인은 규모의 경제(혹은 비경제), 범위의 경제, 집적의 경제, 구도의 경제 등이 협력관계에서 발생하는 혜택의 근본 원천이다. 기술과 제도의 발전, 시장과 경쟁환경의 변화에 따른 기업간 협력의 필요성은 갈수록 증대되고 있다. 소비자들의 요구는 매우 개성화 다양화되고 종합화되는 추세이다. 더불어 기술개발의 비용이 큰 폭으로 증가하고 있으며, 경쟁의 격화로 기술 및 제품의 진부화도 급속도로 이루어지고 있다. 세계화 상품고도화 서비스산업화 정보화 등으로 특징지워지는 새로운 경쟁환경 아래에서 장기적으로 기업의 경쟁력을 향상시키기 위해서는 시장중심적인 관점에서 형성된 기업간 전략적 연계를 바탕으로, 정보의 집적을 통해 다양한 생산성 향상 혹은 관계효율성 향상의 경제를 추구하는 것이 필연적 전제 조건이 되었다. 기업간 경쟁보다는 최종제품의 생산과 판매를 위해 형성된 기업네트워크간의 경쟁이 중시되는 시대인 것이다. 동서간(東西間) 중소기업(中小企業)의 협력(協力)을 새삼스럽게 논의하는 것은 다분히 정치적이라는 느낌을 준다. 경제적인 관점에서 실익이 있음에도 불구하고 동서간 중소기업의 협력이 이루어지지 못하고 있다면, 그 이유는 기업정보의 수집과 유통상의 문제이거나 문화나 기업관행에 대한 잘못된 선입관에서 비롯된 관계 관리비용 계산상의 문제일 것이다. 현실적으로 이 가능성은 매우 낮다. 산업의 발전 정도나 연관성에 있어서 동서축보다는 남북축을 따라 기업간 협력이 이루어질 수 밖에 없는 우리나라의 현재 상황이 동서간보다는 남북간 경제교류를 유도하고 있는 것이다. 동서간 중서기업 협력체제의 구축에 대한 논의가 본질적으로 정치적 관심에서 비롯되었다는 전제 하에, 구축의 방안을 논의하고자 한다. 경제적으로도 타당하면서 정치적으로 관심을 유발할 수 있는 협력체제 구축방안으로, 기업간 네트워크의 조직 주체로서 최근에 논의되고 있는 새로운 형태의 마케팅회사를 동서간에 공동으로 설립할 것을 제안한다. 영구 지속적 공동사업관계보다는 프로젝트별 공동사업을 전제로 기업들 사이의 효과적인 네트워크를 형성함으로써 일종의 가상적 기업을 결성할 필요가 있다. 이러한 기업간 네트워크 형성의 실행주체가 될 수 있는 새로운 마케팅 전문기업의 형태로는 공동회사(空洞會社)(hollow company), 종합상사(綜合商社)(General Trading Company), 거래형 마케팅회사(Marketing Exchange Company), 변환형 마케팅회사(Marketing Coalition Company) 등을 들 수 있다. 양 지역에서는 소비자환경과 기술환경의 특성 및 양 지역의 경제에 대한 파급효과를 고려하여 가장 적합한 마케팅회사의 유형은 선택하여 육성하고, 이를 중심으로 강력한 양 지역 및 다른 지역에 입지한 기업간의 네트워크를 구축하여야 한다. 마케팅회사를 설립하고 완전한 마케팅 서비스를 제공할 수 있도록 육성하기 위해서는 많은 투자가 필요하다. 마케팅회사의 핵심기능 분야인 금융부문, 정보부문, 영업조직 등은 모두 막대한 투자를 필요로하는 기능영역이다. 정보부문은 기술의 발전과 범세계적인 정보관련기관과의 제휴를 통해 독자적인 구축이 어느 정도 가능하나, 영업조직의 구축을 위해서는 기존업체와의 연대가 필수적인 것으로 판단된다. 지속적으로 효과적인 기업간 네트워크를 형성하고 유지하기 위해서는 또한 기업간 관계를 관리하는 방식과 제도 및 수단에 대한 연구가 필요하다. 양 지역 산 학 관의 공동노력을 통해서 새로운 경제 환경에 가장 적합한 기업 형태로 제시된 바 있는 마케팅 전문회사 중심의 기업간 네트워크를 성공적으로 구축한다면, 양 지역 및 국가 경제의 지속적인 동력원이 될 수 있을 것이다

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.49-59
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• 1985

Formulation of the geometric optimization for truss structures based on the elasticity theory turn out to be the nonlinear programming problem which has to deal with the Cross sectional area of the member and the coordinates of its nodes simultaneously. A few techniques have been proposed and adopted for the analysis of this nonlinear programming problem for the time being. These techniques, however, bear some limitations on truss shapes loading conditions and design criteria for the practical application to real structures. A generalized algorithm for the geometric optimization of the truss structures which can eliminate the above mentioned limitations, is developed in this study. The algorithm developed utilizes the two-phases technique. In the first phase, the cross sectional area of the truss member is optimized by transforming the nonlinear problem into SUMT, and solving SUMT utilizing the modified Newton-Raphson method. In the second phase, the geometric shape is optimized utilizing the unidirctional search technique of the Rosenbrock method which make it possible to minimize only the objective function. The algorithm developed in this study is numerically tested for several truss structures with various shapes, loading conditions and design criteria, and compared with the results of the other algorithms to examme its applicability and stability. The numerical comparisons show that the two-phases algorithm developed in this study is safely applicable to any design criteria, and the convergency rate is very fast and stable compared with other iteration methods for the geometric optimization of truss structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.39-55
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• 1992

In this research, a Three Level Decomposition technique has been developed for configuration design optimization of truss structures. In the first level, as design variables, behavior variables are used and the strain energy has been treated as the cost function to be maximized so that the truss structure can absorb maximum energy. For design constraint of the optimal design problem, allowable stress, buckling stress, and displacement under multi-loading conditions are considered. In the second level, design problem is formulated using the cross-sectional area as the design variable and the weight of the truss structure as the cost function. As for the design constraint, the equilibrium equation with the optimal displacement obtained in the first level is used. In the third level, the nodal point coordinates of the truss structure are used as coordinating variable and the weight has been taken as the cost function. An advantage of the Three Level Decomposition technique is that the first and second level design problems are simple because they are linear programming problems. Moreover, the method is efficient because it is not necessary to carry out time consuming structural analysis and techniques for sensitivity analysis during the design optimization process. By treating the nodal point coordinates as design variables, the third level becomes unconstrained optimal design problems which is easier to solve. Moreover, by using different convergence criteria at each level of design problem, improved convergence can be obtained. The proposed technique has been tested using four different truss structures to yield almost identical optimum designs in the literature with efficient convergence rate regardless of constraint types and configuration of truss structures.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2007.05a
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• pp.39-50
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• 2007

Sexing from bovine embryos fertilized in vitro implicates a possibility of the sex controlled cattle production. This study was carried out to produce the sex determined cattle through the embryonic sexing by fluorescence in situ hybridization (FISH) technique. FISH was achieved in in vitro fertilized bovine embryos using a bovine Y-specific DNA probe constructed from the btDYZ-1 sequence. Using this probe, a male-specific signal was detected on 100% of Y-chromosome bearing metaphase specimens. The analyzable rate of embryonic sexing by FISH technique was about 93% (365/393) regardless of embryonic stages. As tested single blastomere by FISH and then karyotype with their biopsied embryos, the accuracy of sex determination with FISH was 97.6%. We tried the embryo transfer with sex determined embryos on 15 cattle. Among them, the 5 cattle delivered calf with expected sex last year.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.106-111
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• 1998

This study has been focused on both estrogenic and proliferating activity of genistein (GEN) and bisphenol A (BPA). GEN and BPA enhance the proliferation of estrogen-dependent MCF-7 human breast cancer cells at concentrations as low as 100 nM of GEN and 8 ng/ml of BP A achieving similar effect to that of estradiol at 1 nM. Expression of the estrogen responsive gene, pS2 was also induced in MCF-7 cells by treatment with genistein at dose as low as 1 nM and BPA at dose as low as 4 ng/ml. Using 21 day-old ovariectomized nude mice, we examined end-bud formation and mammary gland development after treatment with bisphenol A or genistein. Compared with untreated control, mammary gland development and end-bud formation were significantly increased in mice fed genistein or bisphenol A (p<0.05). Taken together, it is concluded that GEN and BP A can act as an estrogen agonist resulting in cell proliferation and induction of the estrogen responsive pS2 gene in MCF-7 cells in vitro and in athymic mice in vivo, respectively. Therefore, it is suggested that GEN and BP A might modulate human endocrine system and these compounds might be considered as a endocrine modulator at the low levels of doses.