• Journal of Chest Surgery
• /
• 제32권11호
• /
• pp.984-988
• /
• 1999

Background: Donor-specific blood transfusion(DSBT) before organ transplantation has been demonstrated to prolong allograft survival; the mechanism of this effect has remained unclear. Only a few researches have been performed on this subject in our country. Material and Method: To investigate the effect of DSBT, we selected 5 donor recipient combinations using rats of pure strain such as PVG, ACI, and LEW. One ml of donor whole blood was transfused to each recipient through the femoral vein 7 days prior to transplantation. The donor heart was transplanted to the recipient's abdominal vessels heterotopically using modified Ono and Lindsey's microsurgical technique. Five transplantations were done for each combination. Postoperatively, donor heart beat was palpated everyday through the recipent's abdominal wall. Rejection was defined as complete cessation of donor heart beat. Result: The allogeneic heart grafts transplanted from PVG strain to ACI strain(PVG ACI) without DSBT were acutely rejected(mean survival 10.2 days). With pretransplant DSBT, the cardiac allografts in PVG ACI and LEW PVG combinations survived indefinitely(more than 100 days), those in ACI PVG combination survived 12 to 66 days(mean 31.8 days), those in PVG LEW survived 8 to 11 days(mean 10.0 days), and those in ACI LEW survived 7 to 9 days(mean 8.0 days). In brief, DSBT prior to heart transplantation was definitely effective in PVG ACI and LEW PVG combinations and moderately effective in ACI PVG combination, but not effective in PVG LEW and ACI LEW combinations. Conclusion: DSBT prior to heart transplantation showed variable effects, but might prolong cardiac allograft survival indefinitely in some donor recipient strain combinations. The mechanism of this effect should be further investigated.

• Bulletin of the Korean Chemical Society
• /
• 제35권7호
• /
• pp.2081-2085
• /
• 2014

Second-order rate constants ($k_N$) have been measured spectrophotometrically for the reactions of phenyl 2- pyridyl carbonate (6) with a series of cyclic secondary amines in MeCN at $25.0{\pm}0.1^{\circ}C$. The Br${\o}$nsted-type plot for the reaction of 6 is linear with ${\beta}_{nuc}$ = 0.54, which is typical for reactions reported previously to proceed through a concerted mechanism. Substrate 6 is over $10^3$ times more reactive than 2-pyridyl benzoate (5), although the reactions of 6 and 5 proceed through the same mechanism. A combination of steric hindrance, inductive effect and resonance contribution is responsible for the kinetic results. The reactions of 6 and 5 proceed through a cyclic transition state (TS) in which H-bonding interactions increase the nucleofugality of the leaving group (i.e., 2-pyridiniumoxide). The enhanced nucleofugality forces the reactions of 6 and 5 to proceed through a concerted mechanism. In contrast, the corresponding reaction of 4-nitrophenyl 2-pyridyl carbonate (7) proceeds through a stepwise mechanism with quantitative liberation of 4-nitrophenoxide ion as the leaving group, indicating that replacement of the 4-nitrophenoxy group in 7 by the PhO group in 6 changes the reaction mechanism (i.e., from a stepwise mechanism to a concerted pathway) as well as the leaving group (i.e., from 4-nitrophenoxide to 2-pyridiniumoxide). The strong electron-withdrawing ability of the 4-nitrophenoxy group in 7 inhibits formation of a H-bonded cyclic TS. The presence or absence of a H-bonded cyclic TS governs the reaction mechanism (i.e., a concerted or stepwise mechanism) as well as the leaving group (i.e., 2-pyridiniumoxide or 4-nitrophenoxide).

• 대한약침학회지
• /
• 제21권3호
• /
• pp.203-206
• /
• 2018

Objectives: There is an increasing number of complex diseases that are progressively more difficult to be controlled using the conventional "single compound, single target" approach as demonstrated in our current modern drug development. TCM might be the new cornerstone of treatment alternative when the current treatment option is no longer as effective or that we have exhausted it as an option. Orthogonal stimulus-response compatibility group study is one of the most frequently employed formulas to produce optimal herbal combination for treatment of multi-syndromic diseases. This approach could solve the relatively low efficacy single drug therapy usage and chronic adverse effects caused by long terms administration of drugs that has been reported in the field of pharmacology and medicine Methods: The present review was based on the Science Direct database search for those related to the TCM and the development of antihypertensive TCM herbal combination using orthogonal stimulus-response compatibility group studies approach. Results: Recent studies have demonstrated that the orthogonal stimulus-response compatibility group study approach was most frequently used to formulate TCM herbal combination based on the TCM principles upon the selection of herbs, and the resulting formulated TCM formula exhibited desired outcomes in treating one of global concerned complex multi-syndromic diseases, the hypertension. These promising therapeutic effects were claimed to have been attributed by the holistic signaling mechanism pathways employed by the crude combination of herbs. Conclusion: The present review could serve as a guide and prove the feasibility of TCM principles to be used for future pharmacological drug research development.

• 대한한의학방제학회지
• /
• 제27권1호
• /
• pp.53-63
• /
• 2019

Objectives : In this study, we investigated the combination effects of Cinnamomi cortex Ethanol Extract (CcEE) and hyperthermia in the human AGS gastric cancer cell line. Methods : AGS cells were treated with the indicated concentrations of CcEE (0, 50 or $60{\mu}g/mL$) for 1h prior to hyperthermia. And then incubated for a further 30 min at the indicated temperatures (37, 42 or $43^{\circ}C$) in a humidified incubator containing 5% $CO_2$ or a thermostatically controlled water bath for hyperthermia. The cell viability was measured by MTT assay, Morphology assay and Trypan blue assay. To investigate the possible molecular signaling pathways, the activation of mitogen-activated protein kinase (MAPK) proteins (ERK, p38 and JNK) and expression of various anti-apoptotic proteins such as Caspase-3, Caspase-9, p53, Cyclin D1 and MMP-2 were assessed by Western blot analysis. In addition, Annexin V and 7-amino-actinomycin D (7-AAD) staining was performed to examine the apoptotic mechanism. Results : Combination of CcEE with hyperthermia effectively suppressed the cell viability and changed cellmorphology compared with CcEE or hyperthermia treatment alone. Combined treatment also abated the expression of Caspase-3, Caspase-9, Cyclin D1 and MMP-2. Whereas, the expression level of p53 was up-regulated by co-treatment. Moreover, combination treatment enhanced phosphorylation of ERK, p38 and JNK. In addition, this combination increased anti-cancer effect by inducing cell death through the apoptosis. Conclusions : Taken together, all these findings suggest that the combination treatment with CcEE and hyperthermia may have therapeutic potential as a promising approach to patients with stomach cancer.

• 한국언론정보학보
• /
• 제33권
• /
• pp.7-52
• /
• 2006

본 연구의 목적은 역사적으로 한국언론에 나타난 교육위기담론의 의미구성방식과 주체 구성방식을 분석함으로써 한국사회의 진보-보수 언론이 갖는 대립적 입장과 이데올로기적 특성들을 드러내는 데 있다. 이를 위해 미셀 페쇠의 담론이론에서 제시된 언어체계의 선택과 조합방식들-선구성과 절합 메커니즘-, 그리고 이데올로기의 주체구성 방식을 이론적으로 검토한 후, 실제 사례분석에 들어가고자 한다. 사례분석의 대상은 조선일보와 한겨레신문이고, 두 신문의 진보와 보수라는 상징적 적대성을 근거로 선정했다. 이와 함께 "교실붕괴"나 "학교붕괴" 등의 교육위기 담론을 현장진술, 원인과 책임규명 그리고 사후대책의 범주 속에서 분석하고자 한다.

• EDISON SW 활용 경진대회 논문집
• /
• 제5회(2016년)
• /
• pp.455-462
• /
• 2016

Recently, followed by rapid growth of robotics field, multi-linkage mechanism which can even pass by rough road is getting lots of attention. In this paper, I focused on Jansen mechanism. It's a kinematics object which is named after Dutch artist Theo jansen. Jansen mechanism embraces structure and mechanism which creates locomotion with the combination of the power and simple structure. Theo jansen suggests a 'Holy number'. It's an ideal ratio of leg components length. However, if there's desired gait locomotion, you have to adjust the ratio and the length. But even slight change of the length could cause a big change at the end-point. To solve this problem, I suggest a reverse engineering method to get a ratio of each links by nonlinear optimization with pre-set desired trajectory. First, we converted a movement of the joint of Jansen mechanism to vectors by kinematics analysis of multi-linkage structure. And we showed the trajectory at the end-point. After that, we set desired trajectory which we found most ideal. Then we got the length of the leg components which draws a trajectory as same as trajectory we set, using Multi-objective genetic algorithm toolbox in MATLAB. Result is verified by Edison designer and mSketch. And we analyzed if it could pass through the obstruction which is set dynamically.

• 소음진동
• /
• 제7권4호
• /
• pp.669-679
• /
• 1997

This paper deals with a study of striker type impact hammer drill for improving the drilling performance. The study was performed through a numerical simulation of the impact hammer mechanism and an experimental comparison of the numerical simulation results was followed. Optimization of the impact mechanism was also performed. The numerical model of the impact hammer drill takes into account the striker motion and the effects of the pressure in the cylinder as well as the friction acting on the striker. The equation of motion is solved with the pressure equation in the cylinder including the friction force. The friction is considered as a combination of Coulomb friction and viscous damping friction. At the moment of impact, an ideal impact model that uses restitution coefficient is used to calculate the sudden change of the striker motion. The numerically simulated impact force shows a good agreement with the experimental result and thus, the validity of the numerical model is proven. Based upon the proposed model, an optimization was performed to improve the impact force of the hammer drill. The objective function is to maximize the impact force and the used design variables are striker mass, frequency of piston, bit guide mass, cylindrical diameter and dimensions of the mechanism components. Each design variable and some other conditions that are essential to manitain normal operation of the hammer drill are considered as constraints. The optimized result show a remarkable improvement in impact force and an experimental proof was investigated.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
• /
• pp.634-637
• /
• 2005

Hydrogen adsorption mechanism onto the porous metal-organic frameworks (MOFs) has been studied by density functional theory calculation. The selected functionals for the predict ion of interact ion energies between hydrogen and potential adsorption sites of MOF was utilized after the evaluation with the various functionals for interaction energy of $H_2C_6H_6$ model system the adsorption energy of hydrogen molecule into MOF was investigated with the consideration of the favorable adsorption sites and the orientations. We also calculated the second favorable adsorption sites by geometry optimization using every combination of two first absorbed hydrogen molecules. Based on the calculation of first and second adsorption sites and energies, the hydrogen adsorption into MOF follows a cooperative mechanism in which the initial metal sites initiate the propagation of the hydrogen adsorption on the whole frameworks. In addition, it was found that the interaction strength between the simple benzene ring with hydrogen is significantly reinforced when the benzene ring has been incorporated into the framework of MOFs.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.103-106
• /
• 2004

We have studied a conduction mechanism and equivalent circuit analysis in $Alq_3$ based Organic Light Emitting Diode. The conduction mechanism in organic light emitting diode can be classified into three regions; ohmic region, space-charge-limited current (SCLC) region and trap-charge-limited current (TCLC) region depending on the region of applied voltage. Equivalent circuit model of organic light emitting diode can be established using a parallel combination of resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

• 제어로봇시스템학회논문지
• /
• 제6권9호
• /
• pp.796-802
• /
• 2000

A master-slave system for teleoperation is usually used to control the robor's motion on remote place such as abyss, outer space etc.. When the slave robot is a humanoid one, it can make a better performance if the configuration of the master arm is similar to that of the slave arm and of the human. The master arm proposed in this paper has a type to be put on the human arm, that is, the exoskeleton type, and has a combination of serial joint and parallel mechanism imitating the human's arm structure of muscles and bones, so called hybrid mechanism so that it can follow arm's movement effectively. But it is easy to solve the forward kinematis of the parallel structure because relating equations are implicit functions. In order to solve that, the virtual joint angle corresponding to human arm's joint is introduced and a sequential computation step is employed in calculating virtual joint angles and the posture of the end effector. Also validity is checked up through computational simulation.