• Proceedings of the Korean Geotechical Society Conference
• /
• 1998.05a
• /
• pp.35-81
• /
• 1998

Distinct Element Method(DEM) has a great advantage to model the discontinuous behaviour of jointed rock masses such as rotation, sliding, and separation of rock blocks. Geometrical data of joints by a field monitoring is not enough to model the jointed rock mass though the results of DE analysis for the jointed rock mass is most sensitive to the distributional properties of joints. Also, it is important to use a properly joint law in evaluating the stability of a jointed rock mass because the joint is considered as the contact between blocks in DEM. In this study, a stochastic modelling technique is developed and the dilatant rock joint is numerically modelled in order to consider th geometrical and mechanical properties of joints in DE analysis. The stochastic modelling technique provides a assemblage of rock blocks by reproducing the joint distribution from insufficient joint data. Numerical Modelling of joint dilatancy in a edge-edge contact of DEM enable to consider not only mechanical properties but also various boundary conditions of joint. Preprocess Procedure for a stochastic DE model is composed of a statistical process of raw data of joints, a joint generation, and a block boundary generation. This stochastic DE model is used to analyze the effect of deviations of geometrical joint parameters on .the behaviour of jointed rock masses. This modelling method may be one tool for the consistency of DE analysis because it keeps the objectivity of the numerical model. In the joint constitutive law with a dilatancy, the normal and shear behaviour of a joint are fully coupled due to dilatation. It is easy to quantify the input Parameters used in the joint law from laboratory tests. The boundary effect on the behaviour of a joint is verified from shear tests under CNL and CNS using the numerical model of a single joint. The numerical model developed is applied to jointed rock masses to evaluate the effect of joint dilation on tunnel stability.

• Radiation Oncology Journal
• /
• v.18 no.4
• /
• pp.283-292
• /
• 2000

Purpose :A retrospective review of 72 patients with locally advanced gallbladder carcinoma, between January 1990 and December 1996, was peformed. Survival results and prognostic factors are analyzed for the patients treated with a various modalities. Materials and Methods :We patients were classified by treatment modality: group 1 included to 27 patients treated with palliative surgery alone, and group 2 for 11 patient treated with palliative surgery and radiotherapy; group 3 for 18 patients not treated by any treatment modality, and group 4 for 16 patients treated with radiotherapy alone. Age distribution ranged from 35 to 80 years with mean of 63 years. The stage was classified by TNM and Nevin's staging system; all patients had an advanced stage more than III. Palliative surgery was done in .: patients and adiuvant radiation therapy (RT) was followed in 11. For 34 patients, in whom no resection was tried, definitive RT was done in 16. Radiation delivered to tumor site and draining nodes up to 45~61.2 Gy using 10 MV linear accelerator. Chemotherapy was given to 25 patients with 5-FU based regimens. Results :Modian suwival time was 10.3 months and 3-year survival rates (3-YSR) were 13.0$\%$ in all patients. Survival rates according to the treatment modalities were as followed; in palliative surgery alone, 3-YSR was 2.5$\%$; in palliative surgery and adjuvant RT, 3-YSR was 45.5$\%$, in no treatment group, 3-VSR were 8.3$\%$; and definitive RT was 13.1$\%$. It was better survival in additional RT after palliative surgery group than palliative surgery alone (p=0.0009). It was better survival in definitive RT group than no treatment group (p=0.002). Significant prognostic factors by univariate analysis were treatment moonlities, the type of tumor and TNM stage. Significant prognostic factors by multivariate analysis were treatment modalities, the type of tumor and the presence of jaundice. Conclusion : It is suggested that RT could be potentially of effective as adjuvant treatment modalities after palliative surgery or primary treatment for locally advanced and unresectable gallbladder carcinoma.

• Korean Journal of Microbiology
• /
• v.39 no.3
• /
• pp.166-174
• /
• 2003

Microcystin produced by cyanobacteria in surface waters, such as eutrophic lake and river, is a kind of serious environmental problems due to its toxicity to human and wild animals. Microcystin is synthesized nonribosomally by the large modular multi-functional enzyme complex known as microcystin synthetase encoded by the mcy gene cluster. Amplification of mcy genes by PCR from cultures and environmental samples is a simple and efficient method to detect the toxigenic Microcystis. In order to evaluate primers designed to detect toxic microcystin-producing strains, 17 cyanobacterial strains and 20 environmental samples were examined by PCR with 7 pairs of primers. Some microcystin-producing cyanobacteria were not detected with FAA-RAA, TOX4F-TOX4R and FP-RP primers. The fragment of unexpected size was amplified with NSZW2-NSZW1 primers in Microcystis strains isolated from the lakes in Korea. TOX1P-TOX1F primers failed in amplification of toxin-producing strains. Only MSF-MSR and TOX2P- TOX2F primers amplified the fragments of mcy genes from 11 strains of microcystin-producing Microcystis. The water samples taken from 20 lakes in Korea were analyzed by PCR using each of the primers. In all the water samples, cyanobacteria capable of producing microcystin were detected by the PCR with TOX2P-TOX2F primers. These results indicate that TOX2P-TOX2F primers are better than the other primers for detection of microcystin-producing Microcystis strains in Korea. The nucleotide sequences of mcy gene in Microcystis aeruginosa NIER10010 suggest genetic diversity of Korean isolates.

• Korean Journal of Environment and Ecology
• /
• v.27 no.1
• /
• pp.85-98
• /
• 2013

In order to propose effective conservation management plan, this study verified ecological characteristics, humanities and Social characteristics. The research site is private property which is owned belonging to the Kim's of Gimhae that have long history. The study site is more than a thousand years old and was created for protecting from typhoon. There held the religious ritual what is called Dongsinje until 1960s. There have been protected and managed by the villagers. As the results of analysis, the area of windbreak are $12,392.69m^2$. The windbreak is dominated old years deciduous broad-leaved tree such as Zelkova serrata, Celtis sinensis, Aphananthe aspera. Around there were farmlands(52.1%), urbanized area(26.3%), forest area(16.6%). The vegetation communities of windbreak were classified by considering the dominant species and current status of forest. The forest types are following as; A. aspera community(I) which is using less pressure, Platycarya strobilacea-Carpinus coreana-Z. serrata community(II). Z. serrata community(III) which is using high pressure, Z. serrata-A. aspera community(IV), Z. serrata community(V) which is damaged under canopy trees. The windbreak was in good condition whereas, there were concerns the some wrong status was being undermined such as the wrong forest restoration projects in the past, the trails that is penetrating inside the forest, building up education facilities. Therefore, in order to restore the value of windbreak what is so called Suwol forest, we should improve the problems of forest ecosystem such as wrong management, forest fragmentation by facilities and decline in forest by lack of growing the next generation trees. In addition, we should remove excessive resting facilities and lead to passive use of forest. to improve the way of wrong management, moreover, we should close off he trails that is penetrating inside the forest for improving fragmentation. We should restore vegetation restoration and fostering the next generation trees for forest ecosystem. In order to restore unique of histo-cultural and ecological forest landscape, the next generation trees should be grown up that is the dominant species in Suwol forest. Moreover, as a results of comparing the between good vegetation communities and damaged vegetation communities, it is necessary to complementary planting for demeged vegetation communities, therefore there needs to 10.8 under canopy trees, 79.7 shrubs.

• Journal of the Korean Geographical Society
• /
• v.28 no.4
• /
• pp.285-297
• /
• 1993

For the application of the diffusion equation, slope height and maximum slope angle are calculated from the plotted slope profile. Using denudation rate as a solution for the diffusion equation, an apparent age index can be calculated, which is the total amount of denudation through total time. Plots of slope angle versus slope height and apparent age index versus slope height are useful for determining relative or absolute ages and denudation rates. Mathematical simulation plots of slope angle versus slope height can generate equal denudation-rate lines for a given age. Mathematical simulations of slope angle versus age for a given slope height, for equal denudation-rate at a particular profile site, and for comparing to other sites having controlled ages.

• Journal of Gastric Cancer
• /
• v.8 no.4
• /
• pp.237-243
• /
• 2008

Purpose: Postoperative Infectious complications are recognized as major complications that are associated with surgery. Although many studies have focused on the risk factors of postoperative complications, little is known about the risk factors of infectious complications after gastric cancer surgery, and especially after elective gastrectomy. There is now more and more interest in the risk factors of infectious complications in relation to controlling infection and as indicators of qualitatively assessing infectious complications. The aim of this study was to evaluate the risk factors related with infectious complications after performing elective gastrectomy for treating gastric cancer. Materials and Methods: We retrospectively reviewed a total of 788 patients who had undergone elective gastrectomy for gastric cancer between Jan. 2000 and Dec. 2007. The characteristics of the patients were divided according to the patients' factors and the operations' factors. Results: The patients' mean age was 58.9 (range: 24~91) years; 545 were male and 243 were female. The mean duration of the hospital stay was 20.3 days (range: 5~135 days), the mean operation time was 181.3 minutes (range: 65~440 minutes). The total complication rate was 17.1% (n=135) and the complication rate was 38.5% (n=52) among the 135 patients with infectious complications. The infectious complications were surgical site infection (59.7%), Pneumonia (19.3%), intra-abdominal abscess (11.5%), pseudomembranous colitis (5.7%), bacteremia (1.9%) and hepatic abscess (1.9%). On the univariate analysis, the significant risk factors were male gender, blood transfusion, smoking at the time of diagnosis, alcohol drinking, diabetes mellitus and previous cardiovascular disease (P<0.05 for all). On multivariate analysis that used a logistic regression model, the significant independent risk factors were smoking at the time of diagnosis (OR: 2.877. 95% CI: 1.449~5.713), blood transfusion (OR: 3.440, 95% CI: 1.241~9.534), diabetes mellitus (OR: 3.150, 95% CI: 1.518~6.538), and previous cardiovascular disease (OR: 2.784, 95% CI: 1.4731~5.2539). Conclusion: Pre- or post-operative blood transfusion and the patient's medical history such as previous cardiovascular disease, diabetes mellitus, smoking etc. are the risk factors for infectious complications after undergoing elective gastrectomy for gastric cancer. The patients that have these risk factors need to be treated with great care to prevent infectious disease after elective gastrectomy.

• The Korean Journal of Physiology
• /
• v.20 no.1
• /
• pp.1-7
• /
• 1986

It has been well documented that the peripheral autonomic nervous system plays an important role in exocrine pancreatic secretion. However, the role of the central nervous system in pancreatic function is still obscure even though the central nervous system has been known to control gastrointestinal functions through the autonomic nervous system. Since the reticular formation in the mesencephalone seems to integrate the autonomic function, the present study was undertaken to investigate a possible influence of the reticular formation upon the exocrine pancreatic secretion. Twenty·two albino rats fasted for 24 hours were anesthetized by intraperitoneal injection of urethane in a dose of 1 g/kg, The pancreatic duct was cannulated to collect pancreatic juice and bile juice was diverted to the jejunum. The gastroduodenal junction was ligated to Prevent passage of gastic juice into the duodenum. A pair of electrodes were bilaterally inserted in the reticualr formation of the mesencephalone with aid of a stereotaxic apparatus. When the volume of pancreatic juice secreted for 10 min became constant, the reticular formation was electrically stimulated for 10 min. Parameters of the electical stimulation was 1.3V, 40 Hz and 2 msec. When the pancreatic secretion returned to the level before the electrical stimulation, cervical vagotomy (11 rats) or administration of propranolol (11 rats) in a dose of 0.1 mg/kg through the jugular vein was carried out. Ten minutes after the treatment, the electrical stimulation of the reticular formation was repeated. The brain was fixed by perfusion of 10% formaline solution through the heart, and then placement of the electrode tip was examined histologically. Protein concentration and amylase activity in samples of Pancreatic secretion were measured. The electrical stimulation of the reticular formation significantly increased in volume $({\mu}l/10\;min)$, Protein output $({\mu}g/10\;min)$ and amylase output (U/10 min) in the pancreatic secretion. The stimulatroy effects were not affected by the cervical vagotomy but completely abolished by propranolol. Meantime, it was also observed that both vagotomy and propranolol significantly reduced the pancreatic secretory function. These results indicate that the reticular formation in the mesencephalone may exert a stimulatory effect upon the Pancreatic secretory function not through the vagus nerve but through the sympathetic pathway in anesthetized rats.

• Journal of the Korean Geographical Society
• /
• v.28 no.4
• /
• pp.379-391
• /
• 1993

Present-day world economy is characterized by : technology nationalism, economic regionalism, market protectionism, multinational corporations, efc. All nations are striving for intensifying national economic rivalry and seeking after their own interests above everything else. Many regions of the world are also forming trading blocs, which could negatively affect nonmember states. The ultimate way to meet these difficulties is to establish production facilities in the countries imposing trade regulations. However, as the existing models of direct forrign investment (DFI) do not account for the particular nature of Korean firm's DFI activities, a new point of departure is imperative. It is because of this that Korean firms have only limited firm-specific advantages, the basic precondition of extant DFI theories, compared with their developed counterparts.

• Journal of Chest Surgery
• /
• v.39 no.3 s.260
• /
• pp.201-207
• /
• 2006

Background: Percutaneous cardiopulmonary support (PCPS) provides passive support of gas exchange and perfusion, allowing the use of other methods of care for organ recovery, and saves lives of patients with severe cardiopulmonary failure in a wide variety of clinical settings with a minimal risk of bleeding and need for chest re~ exploration. We summarized a single center's experiences with PCPS in patients with cardiogenic shock or cardiac arrest due to the ischemic heart disease. Material and Method: Among the 20 consecutive patients with cardiogenic shock or cardiac arrest from May 1999 to June 2005, Biopump (Medtronic, Inc, Minneapolis, MN) was used in 7 patients and the self-priming, heparin-coated circuit of EBS (Terumo, Japan) was applied to remaining 13 patients. Most of cannulations were performed percutaneously via femoral arteries and veins. The long venous cannulas of DLP (Medtronic inc. Minneapolis, MN) or the RMI (Edwards's lifescience LLC, Irvine, CA) were used with the arterial cannulae from 17 Fr to 21 Fr and the venous cannula from 21 Fr to 28 Fr. Result: The 20 consecutive patients who were severely compromised and received PCPS for the purpose of resuscitation were comprised of 13 cardiac arrests and 7 cardiogenic shocks in which by-pass surgery was performed in 11 patients and 9 ongoing PCls under the cardiopulmonary support. The mean support time on the PCPS was 38$\pm$42 hours. Of the 20 patients implanted with PCPS, 11 patients ($55\%$) have had the PCPS removed successfully; overall, 8 of these patients ($40\%$) were discharged from the hospital in an average surviving time for 27$\pm$17 days after removing the PCPS and survived well with 31$\pm$30 months of follow-up after the procedure. Conclusion: The use of PCPS appears to provide the hemodynamic restoration, allowing the survival of patients in cardiac arrest or cardiogenic shock who would otherwise not survive, and patients receiving PCPS had a relatively long-term survival.

• Journal of Chest Surgery
• /
• v.31 no.5
• /
• pp.466-471
• /
• 1998

Purpose: The safety and efficacy of minimally invasive techniques in congenital heart surgery were tested in this study. Materal and method: Between July 1997 and November 1997, a total of 46 children were underwent minimally invasive cardiac operations at Seoul National University Children's Hospital. Age and body weight of the patients averaged 34.6${\pm}$41.8 (Range: 1∼148) months and 14.5${\pm}$9.9(Range: 3.0∼40.0) kg, respectively. Twenty eight patients were male. Preoperative surgical indications included 15 atrial septal defects, 25 ventricular septal defects, 1 foreign body in aorta, 3 partial atrioventricular septal defects, 1 total anomalous pulmonary venous connection(cardiac type), and 1 tetralogy of Fallot. After creating a small lower midline skin incision starting as down as possible from the sternal notch, a vertical midline sternotomy extended from xyphoid process to the level of the second intercostal space, where one of the T-, J-, I- or inverted C-shaped lower lying mini-sternotomy was completed with a creation of unilateral right or bilateral trap door sternal opening. A conventional direct aortic and bicaval cannulation was routine. Result: A mean length of skin incision was 6.1${\pm}$1.0(range: 4.0∼9.0) cm. A mean distance between the suprasternal notch and the upper most point of the skin incision was 4.0${\pm}$1.1 (range: 2.0∼7.0) cm. Mean cardiopulmonary bypass time, aortic cross-clamp time, and the operation time were 62.9${\pm}$20.0(range: 28∼147), 29.8${\pm}$12.8(range: 11∼79), and 161.1${\pm}$34.5 (range: 100-250) minutes. A mean total amount of postoperative blood transfusion was 71.0${\pm}$68.1 (range: 0∼267) cc. All patients were extubated mean 11.3${\pm}$13.8(range: 1∼73) hours after operation. A mean total amount of analgesics used was 0.8${\pm}$1.8(range: 0∼9) mg of morphine. The mean duration of stay in intensive care unit and hospital stay were 35.0${\pm}$32.2 (range: 10∼194) hours and 6.2${\pm}$2.0(range: 3∼11) days. There were no wound complications and hospital deaths. Conclusion: This short-term experience disclosed that the minimally invasive technique can be feasibly applied in a selected group of congenital heart disease as well as is cosmetically more attractive approach.