• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.134-136
• /
• 1993

This paper presents a novel and efficient method to calculate the critical point of voltage collapse. Conjugate gradient and modified Newton-Raphson methods are employed to calculate two pairs of multiple load flow solutions for two operating conditions, i.e., both +mode and -mode voltages for two loading conditions respectively. Then these four voltage magnitude-load data sets of the bus which is most susceptible to voltage collapse, are fitted to third order polynomial using Lagrangian interpolation in order to represent approximate nose curve (P-V curve). This nose curve locates first estimate of the critical point of voltage collapse. The procedure described above is repeated near the critical point and the new estimate will be very close to the critical point. The proposed method is tested for the eleven bus Klos-Kerner system, with good accuracy and fast computation time.

• Journal of Gastric Cancer
• /
• v.13 no.1
• /
• pp.26-33
• /
• 2013

Purpose: The aims are to: (i) display the multidimensional learning curve of totally laparoscopic distal gastrectomy, and (ii) verify the feasibility of totally laparoscopic distal gastrectomy after learning curve completion by comparing it with laparoscopy-assisted distal gastrectomy. Materials and Methods: From January 2005 to June 2012, 247 patients who underwent laparoscopy-assisted distal gastrectomy (n=136) and totally laparoscopic distal gastrectomy (n=111) for early gastric cancer were enrolled. Their clinicopathological characteristics and early surgical outcomes were analyzed. Analysis of the totally laparoscopic distal gastrectomy learning curve was conducted using the moving average method and the cumulative sum method on 180 patients who underwent totally laparoscopic distal gastrectomy. Results: Our study indicated that experience with 40 and 20 totally laparoscopic distal gastrectomy cases, is required in order to achieve optimum proficiency by two surgeons. There were no remarkable differences in the clinicopathological characteristics between laparoscopy-assisted distal gastrectomy and totally laparoscopic distal gastrectomy groups. The two groups were comparable in terms of open conversion, combined resection, morbidities, reoperation rate, hospital stay and time to first flatus (P>0.05). However, totally laparoscopic distal gastrectomy had a significantly shorter mean operation time than laparoscopy-assisted distal gastrectomy (P<0.01). We also found that intra-abdominal abscess and overall complication rates were significantly higher before the learning curve than after the learning curve (P<0.05). Conclusions: Experience with 20~40 cases of totally laparoscopic distal gastrectomy is required to complete the learning curve. The use of totally laparoscopic distal gastrectomy after learning curve completion is a feasible and timesaving method compared to laparoscopy-assisted distal gastrectomy.

• Journal of the Korean Chemical Society
• /
• v.37 no.9
• /
• pp.806-812
• /
• 1993

Complexes of $Cu(I)(hfac)PR_3$(P: phosphine and R: Me, Et and Bu) as Cu(I)(${\beta}$-diketonate) compounds have been synthesized and their electrochemical properties have been investigated using glassy carbon and carbon microelectrode in aprotic solvent. Reduction process of $Cu(I)(hfac)PR_3$ compounds carried out one electron pathway to Cu(0) by cyclic voltammetry in acetonitrile solution. Chronoamperometric curve using carbon microelectrode shows that these complexes are one electron process and diffusion coefficients are $4.5{\sim}6.7{\times}10^{-6}cm^2$/sec.

• Korean Journal of Animal Reproduction
• /
• v.17 no.1
• /
• pp.49-56
• /
• 1993

Mouse mammary epithelial cells(NMuMG) were plated onto 24 well phates(100,000 cells/well), in DMEM supplemented with 10% fetal calf serum. After serum starvation for 24 hours, EGF)0~100ng/ml) was added simultaneously with IGF-I(10ng/ml), 1$\mu$M photoreactive cAMP(4,5-dimethoxy-2-nitrobenzyl adenosine-3',5' cyclic monophosphate, DMNB) or IGF-I plus DMNB. After 2 hours, the cells were expposed to UV light(300nm, 3 second pulse0 in order to activate DMNB which induces a rapid transient increase in intracellular cAMP upon UV irradiation. DNA synthesis was estimated as incorporation of 3H-thymidine into DNA(1 hour pulse with 1$\mu$Ci/ml, 18~19 hours after UV exposure). Without IGF-I or DMNB, EGF(10 or 100ng/ml) increased DNA synthesis from 8,362 dpm/well in control to 16,345 or 18,684 dpm/well with EGF(pooled SE=1,239 dpm/well, P<0.05). IGF-I or IGF-I plus DMNB alone increased DNA synthesis from 8,362 dpm/well in control to 17,307 or 20,427 dpm/well, respectively(P<0.05). Addition of IGF-I, DMNB or IGF-I plus DMNB into 0~100ng/ml EGF did not significantly change the shape of dose response curve of EGF alone. In other experiment, EGF or IGF-I plus DMNB into 10ng/ml EGF group exhibited interaction effect in DNAsynthesis [EGF(10ng/ml)=18,497; IGF-I＋EGF=22,837; DMNB＋EGF=20,658 ; IGF-I＋DMNB＋EGF=29,658, pooled SE=1,055, P<0.05]. These results indicate that simultaneous activation of EGF, IGF-I and intracellular cAMP interact in DNA synthesis of mouse mammary epithelial cells.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.4 no.3
• /
• pp.165-171
• /
• 2000

Experiments were carried out to measure variations in the oxidation potential and current density using the polarization curves of polycarbonate. The results were then examined to identify the influences affecting the oxidation potential related to various conditions, such as temperature, pH, and oxydase(citrate and lipase). The lines representing the active anodic and cathodic dissolution shifted only slightly in the potential direction relative to temperature, pH, and the effect of the enzyme. The Tafel slope for the anodic and cathodic dissolution was determined such that the reversibility polarization was indicated as being effected by various conditions. The slope of the polarization curves describing the active-to-passive transition region shifted noticeably in their direction. Also, by varying the conditions, the optimum conditions for the most ready transform were identified, including temperature, pH, oxidation rate, and resistance of oxidation potential. The critical oxidation sensitivity(I(sub)r/I(sub)f) of the anodic current density peak and maximum passive current density was also determined, which is used in measuring the critical corrosion sensitivity of a polycarbonate.

• Korean Journal of Animal Reproduction
• /
• v.18 no.2
• /
• pp.95-99
• /
• 1994

The purpose of the present study was to determine the in vivo effect of oxytocin antagonist-I(Al) on uterine oxytocin receptor number (Rn) and/or binding affinity (Kd) in the estrous rat. Anesthetized rats were given a bolus infusion of control or 5${\mu}\textrm{g}$ of AI and sacri-ficed 0.5 and 4 hours later. The uterine tissue was removed, trimmed and frozen. Membrane oxytocin receptors were isolated after homogenization of uterine tissue and differential ultracentrifugation. The oxytocin receptor assay was performed by saturation with cold oxytocin competion with a high specific activity oxytocin antagonist. Rn and Kds were determined by nonlinear curve fitting methods. No differences(p>0.05) between the AI and control treated animals in either oxytocin receptor number or binding affinity was detected in this study. These data suggest that the major mode of action of AI is via competitive inhibition at the uterine oxytocin receptor and not by altering receptor number or binding affinity.

• Journal of Korean Medicine Rehabilitation
• /
• v.15 no.2
• /
• pp.105-105
• /
• 2005

Objectives : The purpose of this study was to investigate the correlation between cervical spine curvature and thermography on neck pain patients. Methods : The cervical spine curvature was assessed on lateral view of plain radiograph by three measurements(Depth of cervical curve, Method of Jochumsen, Angle of cervical curve), then the neck pain patients were divided into straight curvature group(Straight group), normal curvature group(Control I), and no neck pain group(Control II) was selected by random sampling. I measured temperature of the both side Pungji(風池, G20), Kyonjong(肩井, G21), Chonjong(天宗, SI11) by thermography examination on Experimental group(Straight group) and control group(Control I, II), then analyzed the temperature statically with student's t-test, ANOVA. Results : The temperature of six point on Straigt group was lower than that of Control I, but had no significant difference(p>0.05). The temperature of six point on Straigt group was lower than that of Control II. The descent of temperature on Lt. Pungji(風池, G20), Lt. Kyonjong(肩井, G21), Rt. Chonjong(天宗, SI11) had significance(p<0.05). There is no corelation between onset period and mean temperature of six points. Conclusions : Thermography represnets the presence of neck pain, but has no correlation with straight of cervical curvature.

• Clinical and Experimental Pediatrics
• /
• v.52 no.9
• /
• pp.984-990
• /
• 2009

Purpose : Being small for gestational age (SGA) is a risk factor of short stature in children. Genetic background such as mid-parental height (MPH) is known to influence growth of children born SGA. We studied the relationship between growth of children born SGA and MPH and studied the effects of insulin-like growth factor (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP-3) on postnatal growth in children born SGA according to MPH. Methods : Forty-nine neonates born SGA were included in this study. We defined corrected height standard deviation score (cHtSDS) by modified height SDS (HtSDS) based on their MPH. We categorized subjects into group 1 consisting of children with cHtSDS ${\geq}0$ (n=35) and group 2 consisting of children with cHtSDS <0 (n=14), and compared IGF-I and IGFBP-3 between the two groups. Results : The HtSDSs and cHtSDSs in groups 1 and 2 were $0.06{\pm}1.05$ vs. $-0.95{\pm}0.85$ (P=0.000) and $0.78{\pm}0.93$ vs. $-0.46{\pm}0.67$ (P=0.000), respectively. IGF-I SDS was higher in group 1 than in group 2 ($2.82{\pm}3.69$ vs. $0.23{\pm}2.42$, P=0.012). Total cHtSDS ($0.42{\pm}1.03$) was significantly higher than HtSDS ($-0.22{\pm}1.10$) (P=0.000). Conclusion : Our results show that cHtSDS differs significantly from HtSDS. Growth assessment by standardized growth curve does not uniformly show effects of genetic factors. A more accurate assessment of growth uses a personalized corrected growth curve that considers the genetic factor measured by MPH.

• Journal of Chest Surgery
• /
• v.57 no.1
• /
• pp.44-52
• /
• 2024

Background: Visceral pleural invasion (VPI) is a poor prognostic factor that contributes to the upstaging of early lung cancers. However, the preoperative assessment of VPI presents challenges. This study was conducted to examine intraoperative pleural carcinoembryonic antigen (pCEA) level and maximum standardized uptake value (SUVmax) as predictive markers of VPI in patients with clinical T1N0M0 lung adenocarcinoma. Methods: A retrospective review was conducted of the medical records of 613 patients who underwent intraoperative pCEA sampling and lung resection for non-small cell lung cancer. Of these, 390 individuals with clinical stage I adenocarcinoma and tumors ≤30 mm were included. Based on computed tomography findings, these patients were divided into pleural contact (n=186) and non-pleural contact (n=204) groups. A receiver operating characteristic (ROC) curve was constructed to analyze the association between pCEA and SUVmax in relation to VPI. Additionally, logistic regression analysis was performed to evaluate risk factors for VPI in each group. Results: ROC curve analysis revealed that pCEA level greater than 2.565 ng/mL (area under the curve [AUC]=0.751) and SUVmax above 4.25 (AUC=0.801) were highly predictive of VPI in patients exhibiting pleural contact. Based on multivariable analysis, pCEA (odds ratio [OR], 3.00; 95% confidence interval [CI], 1.14-7.87; p=0.026) and SUVmax (OR, 5.25; 95% CI, 1.90-14.50; p=0.001) were significant risk factors for VPI in the pleural contact group. Conclusion: In patients with clinical stage I lung adenocarcinoma exhibiting pleural contact, pCEA and SUVmax are potential predictive indicators of VPI. These markers may be helpful in planning for lung cancer surgery.

• ALGAE
• /
• v.19 no.3
• /
• pp.207-216
• /
• 2004

Characteristics of photosynthesis-light and photosynthesis-temperature relationships were seasonally compared among 4 species, two temperate Sargassurn (S. ringgoldianum and S. spathulophyllum) and two temperate kelp (Ecklonia cava and Eisenia bicyclis), growing in the same habitat in Oura Bay, Shimoda, central Japan. The photosynthesis-irradiance (P-I) curve of each species at the in situ temperature and the photosynthesis-temperature (P-T) curve at near saturation irradiance (400μmol·m^(-2)·s^(-1)) were determined by using differential gas-volumeters. Maximum photosynthetic rates (Prnax) for P-I curves of the two Sargassurn species were higher from summer to autumn than from winter to spring, while those of the two kelp species showed little difference among seasons. Net photosynthetic rates (Pn) at 100-400μmol·m^(-2)·s^(-1) of the Sargassurn species were higher than those of the kelp species in autumn, spring and summer, while in winter the rates were about the same between the Sargassurn and kelp species. Among seasons, the light saturation index (1k) values, dark respiration rates and light compensation points of Sargassurn species differed more than those of kelp species. Optimum temperature for P-T curves of Sargassurn species was 29℃ and that of kelp species was 27℃ in summer, while in winter the former was 27℃ and the latter was 25℃. Pn at 400 μmol·m^(-2)·s^(-1) at 10-33℃ of Sargassurn species were considerably higher than those of kelp species from spring to summer, while from autumn to winter the rates at 5-27℃ were about the same between the two. At supra-optimum temperatures, Pn of kelp species decreased more sharply than those of Sargassurn species in each season. These facts indicate that the two temperate Sargassurn species have a higher potential photosynthetic performance under warmer conditions than the two temperate kelp species even though they grow in the same habitat.