• Journal of Chest Surgery
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• v.33 no.5
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• pp.398-406
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• 2000

Background: Cardiac atrium is an endocrine gland secreting a family of natriuretic peptides. The secretion of atrial natriuretic peptide(ANP) had been shown to be controlled by variable factors. The change in atrial dynamics have been considered as one of the most prominent stimuli for the stimulation of ANP secretion. Hypoxic stress has been shown to increase cardiac ANP secretion. However, the mechanism by which hypoxia increases ANP secretion cardiac ANP secretions. However, the mechanism by which hypoxia increases ANP secretion has not to be defined. Therefore, the purpose of the present study was tow-fold: to develop a protocol to defined the effect of hypoxia on ANP secretion in perfused beating rabbit atria and to clarify the mechanism responsible for the accentuation by hypoxia of ANP secretion. Material and Method: Experiments have been done in perfused beating rabbit atria. ANP was measured by radioimmunoassay. Result: Hypoxic stimulus with nitrogen decreased atrial stroke volume. The decrease in atrial stroke volume recovered basal level during the period of recovery with oxygen. ANP secretion and the concentration of perfusate ANP in terms of extracellular fluid(ECF) translocation which reflects the rate of myocytic release of ANP were increased by hypoxia and returned to basal levels during the recovery. Changes in ECF translocation paralleled by hypoxia and returned to basal levels during the recovery. Changes in ECF translocation paralleled to that of atrial stroke volume. At the start of recovery in atrial storke volume, ECF tranalocation incrased for several minutes. The above responses were stable and reproducible. Glibenclamide treatment prevented the recovery in atrial stroke volume. Increments by hypoxia of ANP secretion and ANP concentration were suppressed by glibenclamide. Conclusion: These results indicate that hypoxia incrased atrial myocytic ANP release and that the mechanism responsible for the accentuation is partially related to the change in K+ATP channel activity.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.1
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• pp.19-25
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• 2009

Purpose: We report mid to long - term results of meniscal transplantation and evaluate the important factors for successful outcomes. Materials and Methods: Between December 1999 and September 2002, 25 meniscal transplantations were performed using fresh frozen allograft. The lateral meniscus was transplanted in 19 cases and medial meniscus in 6 cases. The mean age was 34 years (range, 17~50 years) and the mean follow up was 54.8 months (range, 6~85 months). Preoperative measurements were made using a ruler graded in millimeters. Lateral meniscus was fixed by keyhole technique and medial meniscus was fixed by double bone plug technique with suturing the periphery of the meniscal transplant. All patients were evaluated with Knee Assessment Scoring System (KASS), Lysholm knee score, and Tegner activity scale for daily activity. Results: Symptoms improved in all cases. The average KASS score increased from 61.7 preoperatively to 83.8 postoperatively. The average Lysholm knee score increased from 77.7 preoperatively to 87.7 postoperatively (excellent in 3 cases, good in 17 cases, fair 4 cases, poor 1 case). But painful swellings were 3 cases, numbness in 1 case, and granuloma due to non-absorbable suture material in 1 case. Peroneal nerve palsy in 1 case was recovered after 6 weeks postoperatively. Conclusion: Meniscal allograft transplantation after subtotal or total menisectomy can significantly relieve pain and improve function of the knee joint. The exact preoperative sizing and secure fixation are essential for successful outcomes.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.177-182
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• 2008

This study was carried out to investigate the reaction of lipase-catalyst transesterification using animal fat recovered from fleshing scrap generated during leather making process. Transesterification reaction between fat and primary or secondary alcohol was carried out under the condition of immobilized enzyme catalyst. The conversion rate was the highest when 1.5 mole of methanol was injected by 4 times. As for lipase, Candida antarctica showed the highest conversion rate of 82.2% among the 4 different lipases. It was found that water contained in the fat causes lower conversion rate. The condition of 1.2wt. % of water in the fat decreased the conversion rate by 40%. It was considered that the resulted reactant, fatty acid ester could be used as raw material for biodiesel with the characteristics of not generating SOx and diminishing smoke.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.391-398
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• 2020

If the lost energy produced by a propeller can be partially recovered, the propulsive efficiency can be increased, and the fuel consumption reduced. The devices installed for this purpose are called Energy Saving Devices, of which the Contra-Rotating Propeller system is one of the most effective devices. The first problem to be solved to install the Contra-Rotating Propeller system on a large ship is that the mean pressure generated in the journal bearing needs to meet the design criteria of the classifications. In Korea, however, the practical use is being delayed because it cannot overcome this step. The next step is to lower local pressure to increase the reliability. In this study, to solve the mean pressure problem as the first step of practical use, a product carrier with a short stern shape was selected to reduce the weight of the shafting system, and a suitable shafting-system design plan was proposed. Shaft analysis confirmed that the mean pressure of 0.8 MPa (8 bar), which is a design criterion of the classifications for a journal bearing lining material (white metal), was satisfied. In addition, the necessity of reducing the local pressure was also confirmed.

• Resources Recycling
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• v.27 no.5
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• pp.61-68
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• 2018

The aluminum dross is oxide generated on the surface of the molten metal during the aluminum melting process and it is divided into white dross and black dross according to presence of the Salt flux. White dross has high metal content and is recycled via the melting process. Black dross is largely berried, because the it has a low metal content and difficulty in separating the components. Black dross contains a salt components such as NaCl and KCl, and inorganic materials such as $Al_2O_3$ and MgO, and it is necessary to study the technology to recover and recycle such valuable resources. In this study, a process for recycling aluminum black dross was proposed. The inorganic and soluble substances present in the black dross were separated through crushing-dissolution-solid/liquid separation-decompression evaporating. By controlling the ratio of water and black dross, the recovery condition of the separated product was optimized and we confirmed the highest Salt flux recovery efficiency 91 wt.% at black dross:water ratio 1:9. Finally, Through the synthesis of zeolite using recovered ceramic material, the materialization possibility of black dross was confirmed.

• Acta Via Serica
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• v.1 no.1
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• pp.95-104
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• 2016

The Silk Route in ancient times served as a link between the World's greatest civilizations and as a source of knowledge, art, religion and philosophy. This network of ancient caravan paths formed the first bridge between East and West, where two different civilizations came in contact with their respective cultural traditions and religious beliefs, as well as their scientific and technological achievements. One of the main routes of the Great Silk Route passed through the Karakoram, linking Kashgar with Kashmir and the Gandhara regions. The Karakoram Highway connects the Chinese province with Pakistan and follows the ancient Silk Route, which connected the Heartlands of Asia with the Western fringes and further beyond the entire continent of Europe. Evidences of the history of humankind, ranging from Pre-historic times to the spread of Buddhism from South Asia to China and the Far East, is depicted in the rocky cliffs on the waysides and on rough boulders scattered in the upper valley of the Indus River and its tributaries. The ancient trade routes also carried scholars, teachers, missionaries and monks of different beliefs and practices, who met and exchanged ideas. The Buddhists as well as Zoroastrians and other missionaries all followed the Silk Route, leaving permanent footprints of their passage. The ancient greater Gandhara is situated in the North-West of the Indian Sub-continent, with the steep mountain ranges of the Karakoram, the Pamir and the Hindu-Kush bordering it and the dry areas of Central Asia to its rear. A number of races from Central Asia migrated to Gandhara because of its mild climate and plentiful farm products and fruits. This area was an entry point of Western Culture into India and at the same times the exit point of Indian Culture, including Buddhism, to the West. In Gandhara, the diffusion of different cultures developed an art form, during the 1-7th centuries CE commonly known after its geographic name as "Gandhara Art". The Buddhism's route of introduction into China originated in Gandhara, then reached in Korea and Japan and other countries. The fame of Gandhara however, rested on its capital, "Taxila" which was a great centre of learning. From the time of the Achaemenians, down through Muslim period, Gandhara continued to establish and maintain a link between East & West, as shown by material evidences recovered from Taxila and other Buddhist centres of Gandhara during the course of archaeological excavations.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.162-170
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• 1996

Light cycle Oil(LCO) contains 2,6-dimethylnaphthalene (2,6-DMNA) which is used as the basic material for high performance engineering plastics and liquid crystal polymer. This study was experimentally investigated to concentrate a mixture of dimethylnaphthalene(DMNA) isomers in the LCO by extraction-distillation combination as a pretreatment for separation and purification of 2,6-DMNA in the LCO. Furthermore, concentration of a mixture of DMNA isomers in the LCO compared between distillation and extraction-distillation combination. The recovery of aromatics in the LCO was performed by batch cocurrent multistage extraction with dimethylsulfoxide and water mixture as solvent. The concentration of naphthalene group(carbon number 10-12) in the extracted mixture is higher than that in the LCO. The yield for naphthalene group increased with decreasing carbon number. The yield for a mixture of DMNA isomers obtained in 5 equilibrium extration runs was about 65%. the separation of individual components with extractedmixture was tested by batch distillation. Futhermore, for recovery of a mixture of DMNA isomers of high concentration, distillate containing DMNA was distilled. As a result, a mixture of DMNA isomers with high concentration such as 60wt% was recovered. The extraction-distillation combination was more effective than the distillation to concentration a mixture of DMNA isomer in the LCO.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.257-263
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• 1999

It is well known that discard of seminal plasma from the semen and separation of motile sperm should be preceded before insemination for IUI or IVF. Till now, more than ten kinds of semen treatment methods have been developed. Of those, swim-up and Percoll methods have been used widely in ART laboratories as a routine semen treatment methods because of its advantages. However, there are reports that Percoll can make a genetic trouble because of its chemical structure and therefore the necessity has been arisen to substitute Percoll for other equivalent materials. This study was performed to evaluate the effects of three different sperm preparation methods (swim-up, Percoll and Sil-Select) on sperm motility, sperm recovery rate and fertilization rate. Also, the feasibility of using Sil-Select instead of Percoll in ART was evaluated. Each semen samples were divided into three fractions and motile sperm were recovered by swim-up, Percoll and Sil-Select gradient centrifugation methods. Normal and sub-normal criteria of fifteen semen samples and seventeen IVF cycles were included in these study. As results, no significant difference was found in sperm recovery rate in normal semen treated by a Swim-up, Percoll and Sil-Select method ($13.2{\times}10^6,\;17.5{\times}10^6\;and\;17.7{\times}10^6$ respectively). The initial sperm motility was 61.9% and this increased to 87.1%, 92.6% and 89.5% through Swim-up, Percoll and Sil-Select treatment, respectively. Higher motility was observed in Percoll and Sil-Select treated groups (81.5%, 79.2%, respectively) than swim-up group (66.8%) after incubation for 24hrs. In sub-normal group, sperm recovery rates were higher in Sil-Select group $(2.9{\times}10^6)$ than Percoll gradients group $(1.8{\times}10^6)$. In IVF cycles, the outcomes of fertilization using sperm treated by swim-up and Sil-Select group were similar (82.2%, 79.7% respectively). In conclusion, our results indicate that Sil-Select can be used as a substitute material for sperm preparation instead of Percoll.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.304-311
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• 2001

A study has been carried out on the extraction chromatographic separation of fission products from spent pressurized water reactor (PWR) fuels for inductively coupled plasma atomic emission spectrometric analysis. Impregnation capacity of tri-n-butyl phosphate (TBP), which is well known as an extractant in the field of uranium separation from various nuclear grade materials, on Amberlite XAD polymeric macroporous support materials was measured. Amberlite XAD-16 of which the surface area is the highest was selected as a support material because its TBP impregnation capacity was the largest in Amberlite XADs. Sorption behaviour of this TBP impregnated resin was investigated for the fission product elements using acidic solutions simulated for dissolver solutions of spent PWR fuels. The parameters affecting the performance of the separation system were optimized. The fission product elements studied excluding Pd and Ru were quantitatively recovered with the precision of less than 3.1%.

• Journal of Chest Surgery
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• v.35 no.11
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• pp.807-811
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• 2002

Due to its less invasive nature and superior visual field, video-assisted thoracescopic excision of mediastinal mass is thought to be comparable to open thoracotomy. Material and Method : From January 1995 to August 2001, the medical records of 38 patients who underwent video-assisted thoracoscopic excision of mediastinal mass was retrospectively analyzed. The outcome of these patients were compared with 5 patients who converted to thoracotomy Result: Male to female ratio was 13(34.2%) : 25(65.8%), and mean age was 39.2$\pm$35.4 years. Regarding the pathology, there were 8 neurilemmomas(21.1%), 6 thymic cysts (15.8%), 5 teratomas(13.2%), 5 ganglioneuromas(13.2%), 4 bronchogenic cysts(10.5%), 3 pericardial cysts(7.9%), 3 thymomas(7.9%), and 2 lymphangiomas(5.3%). The mean operation time was 110.6$\pm$7.0 minutes, mean postoperative tube stay was 4.2$\pm$0.4 days, mean postoperative hospital stay was 5.2$\pm$0.4 days, and mean number of injection of analgesics was 1.9$\pm$0.4 times. Although the mean values for the above indices were less than those of the thoracotomy conversion cases, they were statistically insignificant. Postoperative complications of videoassisted thoracoscopic excision included chylothorax, prolonged air leakage, and unilateral phrenic nerve palsy, all of which recovered before patient discharge. There was, however, permanent unilateral ptosis in one patient. Conclusion : As video-assisted thoracoscopic excision of mediastinal mass is safe, less painful, conducive to earlier recovery and cosmetically more appealing, a more active application of this technique is recommeded.