• Journal of Chest Surgery
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• v.48 no.1
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• pp.25-32
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• 2015

Background: We evaluated operative outcomes after third or more cardiac operations for valvular heart disease, and analyzed whether pericardial coverage with artificial membrane is helpful for subsequent reoperation. Methods: From 2000 to 2012, 149 patients (male : female=70 : 79; mean age at operation, $57.0{\pm}11.3$ years) underwent their third to fifth operations for valvular heart disease. Early results were compared between patients who underwent their third operation (n=114) and those who underwent fourth or fifth operation (n=35). Outcomes were also compared between 71 patients who had their pericardium open during the previous operation and 27 patients who had artificial membrane coverage. Results: Intraoperative adverse events occurred in 22 patients (14.8%). Right atrium (n=6) and innominate vein (n=5) were most frequently injured. In-hospital mortality rate was 9.4%. Total cardiopulmonary bypass time ($225{\pm}77$ minutes vs. $287{\pm}134$ minutes, p=0.012) and the time required to prepare aortic cross clamp ($209{\pm}57$ minutes vs. $259{\pm}68$ minutes, p<0.001) increased as reoperations were repeated. However, intraoperative event rate (13.2% vs. 20.0%), in-hospital mortality (9.6% vs. 8.6%) and postoperative complications were not statistically different according to the number of previous operations. Pericardial closure using artificial membrane at previous operation was not beneficial in reducing intraoperative events (25.9% vs. 18.3%) and shortening operation time preparing aortic cross clamp ($248{\pm}64$ minutes vs. $225{\pm}59$ minutes) as compared to no-closure. Conclusion: Clinical outcomes of the third or more operations for valvular heart disease were acceptable in terms of intraoperative adverse events and in-hospital mortality rates. There were no differences in the incidence of intraoperative adverse events, early mortality and postoperative complications between third cardiac operation and fourth or more.

• Korean Journal of Head & Neck Oncology
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• v.19 no.1
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• pp.25-33
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• 2003

Background and Objectives: The Herpes Simplex type 2 Defective Infectious Single Cycle virus (DISC virus) is attenuated virus originally produced as viral vaccines but are also efficient gene transfer vehicle. The main goals of this study were to examine the efficiencies of the gene transfer using DISC vectors for various head and neck squamous cell carcinoma cell lines and to evaluate the efficacy of vaccination with DISC virus carrying a immunomodulatory genes (GM-CSF) as cancer therapy in a organotopic oral cavity squamous cell cancer model. Materials and Methods : We determinated the gene transfer efficiency of DISC virus by x-gal stain method and proved gene and protein expression of DISC-GMCSF transfected SCCVII cells by RT-PCR and ELISA method. Also we evaluated the ex vivo vaccination effects of SCCVII/GMCSF (DISC-GMCSF transfected SCCVII vaccine) vaccine on preventing the recurrence of micro-residual tumor. After the vaccination of SCCVII/GMCSF, specific cytotoxic T-cell responses was evaluated by CTL assay. Results: At an MOI of 10 DISC virus showed 64-88% of transfection rates in various head and neck squamous cancer cell lines. SCCVII cells transduced by DISC virus vector (MOI=10) carrying the GM-CSF gene, produced 4.5 nanogram quantities of GM-CSF per $10^6$ cells. In vivo vaccination using tumor cells transduced ex vivo with DISC-GMCSF resulted in better protection rate against subsequent tumor recurrence in organotopic oral cavity cancer model. Although tumor free survival rate was not statistically significantly increased in vaccination group (p=0.078), tumor specific cytotocic T-cell responses were significantly increased in SCCVII/GMCSF vaccination group. Conclusion: These data demonstrate that; 1) The DISC virus vector is capable of efficient gene transfer to various head and neck squamous cancer cell lines, 2) GM-CSF secreting genetically modified tumor vaccine (SCCVII/GMCSF) efficiently protected against tumor recurrence in organotopic micro-residual oral cavity cancer model and produced tumor specific cytotoxic T-cell response. DISC virus-mediated, cytokine gene transfer may prove to be useful as a clinical therapy for head and neck cancers.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.1
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• pp.33-46
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• 2019

Even though Korea is strengthening the support for startups due to the limitations of growth policies focusing on large companies, the survival rate of startups is very low, so that there should be more efforts to increase the survival rate of startups. As the existing startup support institutions have provided only fragmentary supports to startups, it would be necessary to have the comprehensive support institutions. As an alternative, the accelerator providing the comprehensive support such as spatial support, education, mentoring, networking, seed investment, and connection for follow-up investment to the initial startups was legalized in Korea of 2016, based on the registration system. Currently, within less than two year from then, there have been much interest in it enough to have about 136 registered accelerators. In the United States, the accelerator was introduced more than ten years ago. In Korea, however, it is still in the initial stage, so that the researches or social consensus on the accelerator are not sufficient. Thus, this study aims to suggest the measures for the development of accelerator and the consensus on the decision making for the selection of accelerator of startups, by researching which parts are considered when startups in the accelerator stage select the accelerator. As a result of the empirical analysis, the factor that has the greatest influence on decision making factors when startup chooses an accelerator was the subsequent investment attraction. This can be explained to the accelerator as desired, considering the factor that the startup of the initial stage places the most importance on growth as investment. We hope that these research results will be sustainable in future research related to accelerators, in hopes that it will be useful for establishing accelerator policies for domestic startups and direction for revitalizing related industries.

• Tunnel and Underground Space
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• v.32 no.2
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• pp.107-119
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• 2022

Excavation-Disturbed Zone (EDZ) is an important design factor in constructing final disposal facilities for spent nuclear fuel, since EDZ affects mechanical stability including a spacing between disposal holes, and the hydraulic properties within EDZ plays a significant role in estimating in-flow rate of groundwater as well as a subsequent corrosion rate of a canister. Thus, it is highly required to characterize in-situ EDZ with precision and control the EDZ occurrence while excavating disposal facilities and constructing relevant underground research facilities. In this report, we not only reviewed EDZ-related researches carried out in the ONKALO facility of Finland but also examined appropriate methods for field inspection and quality control of EDZ occurrence. From the review, GPR can be the most efficient method for in-situ characterization of EDZ since it does not demand drilling a borehole that may disturb a surrounding environment of caverns. And the EDZ occurrence was dominant at a cavern floor and it ranged from 0 to 70 cm. These can provide useful information in developing necessary EDZ-related regulations for domestic disposal facilities.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3250-3259
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• 2022

A new approach to the use of rice straw as a difficult-to-recycle agricultural waste was proposed. Potassium aluminosilicate was obtained by spark plasma sintering as an effective material for subsequent immobilization of ¹³⁷Cs into a solid-state matrix. The sorption properties of potassium aluminosilicate to ¹³⁷Cs from aqueous solutions were studied. The effect of the synthesis temperature on the phase composition, microstructure, and rate of cesium leaching from samples obtained at 800-1000 ℃ and a pressure of 25 MPa was investigated. It was shown that the positive dynamics of compaction was characteristic of glass ceramics throughout the sintering. Glass ceramics RS-(K,Cs)AlSi₃O₈ obtained by the SPS method at 1000 ℃ for 5 min was characterized by a high density of ~2.62 g/cm³, Vickers hardness ~ 2.1 GPa, compressive strength ~231.3 MPa and the rate of cesium ions leaching of ~1.37 × 10^-7 g cm^-2·day^-1. The proposed approach makes it possible to safe dispose of rice straw and reduce emissions into the atmosphere of microdisperse amorphous silica, which is formed during its combustion and causes respiratory diseases, including cancer. In addition, the obtained is perspective to solve the problem of recycling long-lived ¹³⁷Cs radionuclides formed during the operation of nuclear power plants into solid-state matrices.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.68-68
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• 2001

Blastocyst formation, consisting of the inner cell mass (ICM) and trophectoderm (TE), is the first differentiation process during embryonic development in mammals. It has been hypothesized that the proportion of ICM to TE in the blastocyst may be crucial for subsequent developmental competence of early embryos, which it may be expressed as a sensitive indicator for evaluating in vitro systems. In this study ICM/total cell ratio of nuclear transfer (NT) embryos was compared with IVF-derived and in vivo embryos. Somatic cell nuclei obtained from a fetus at Day 40 of gestation were transferred into the enucleated oocyte and then cultured in NCSU 23 medium for 6 days as previously described (Koo et al., Biol. Reprod. 2000; 63:986-992). ICM and TE cells of blastocysts were determined by using a differential staining method (Han et al., Biol. Reprod. 1999; 60:1110-1113). Development rate (9.8$\pm$2.5%, 23/225) to the blastocyst stage of NT embryos was lower than IVF embryos (23.8$\pm$2.7%, 53/223). Thus, a difference was detected in the in vitro developmental rate to blastocyst stage between NT and IVF-derived embryos (P<0.05). In the next experiment, we investigated ICM and TE nuclei to assess the quality of blastocysts that produced by NT, IVF and in vivo, respectively. NT blastocysts (27.6$\pm$8.3) showed a smaller total cell number than IVF-derived (42.6$\pm$17.4) and in vivo embryos (283.9$\pm$103.5) (P<0.05). Ratios of ICM/total cells in NT, IVF and in vivo blastocysts were 15.1$\pm$ 18.6% (n=56), 12.3$\pm$9.2% (n=57) and 30.4$\pm$6.8% (n=40), respectively. Individual blastocysts for the ratio of ICM/total cells were assigned to 3 groups (I; <20%, II; 20 to 40% and III;>40%). As the results, most in vivo blastocysts (97.5%, 39/40) were distributed into group II while most NT (78.6%, 44/56) and IVF-derived blastocysts (82.5%, 47/57) were allocated to group I. Thus, our data show that NT or IVF-derived embryos have aberrant morphology during early development in vitro systems, suggesting that these anomalies may result in developmental failures of the NT embryos to term.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.2 no.2
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• pp.53-61
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• 2009

Purpose: This study was designed to evaluate the clinical usefulness of serial ultrasonography (USG) after arthroscopic rotator cuff repair and to assess the re-tear rate and the re-tear time according to the tear sizes and the repair method. Materials and Methods: Between January 2008 and June 2008, 52 patients were treated with arthroscopic rotator cuff repair, Of the 52 patients, 29 patients that had undergone more than six months follow-up underwent preoperative USG examinations and subsequent arthroscopic examinations. MRI and USG findings were compared with intraoperative results of arthroscopic examinations. The postoperative integrity of the rotator cuff was observed using serial USG examination performed postoperatively at two weeks, six weeks, three months, and six months. Results: Small to medium rotator cuff tear were identified in 10 patients where the double pulley suture bridge (DPSB) technique was performed; the re-tear rate was 20%. For 19 patients with large to massive rotator cuff tears, the re-tear rates was 100% for six patients who had undergone tendon to tendon (TT) repair, the re-tear rate was 50% for two patients who had undergone tendon to tendon and bone to tendon (TTBT) repair and the re-tear rate was 55% for11 patients where the DPSB technique was performed. Re-tear rates according to follow-up periods were 7% from two to six weeks, 66% from six weeks to three months and 27% from three to six months postoperatively. Conclusion: Serial USG examinations after arthroscopic rotator cuff repair were useful to assess the re-tear rate and the re-tear time. In addition, USG examination were useful for treatment planning during postoperative rehabilitation.

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.51-57
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• 2017

Subsequent to the introduction of the "Laws on Consumption Promotion of Livestock Products" in 2002, a mandatory check-off system for the egg industry was introduced in June 2009. Unlike other livestock products, the check-off on eggs is financed not from the sale of the egg-the end product-but from the spent hen. Variables such as the falling price of spent hens lead to a low financing rate; The present farm allotment rate of 14%, introduced in 2015, is much higher than the 0.2% to 0.3% check-off rate in other types of business, thus placing a huge burden on farms. When check-off is financed from the egg, it is expected that 6.5 billion won will be raised using a rate of 0.3% of sale proceeds, Therefore, it is urgent for the government to establish infrastructure to enable producers and merchants to do business through Grade & Packing centers. This can be achieved by the staged construction of local Grade & Packing centers. Check-off should continue to be financed from the present spent hen until this infrastructure is established, and an institutional strategy should be provided by the government to raise the financing rate accurately and transparently using statistical treatment of supply data for spent hens as a short-term alternative.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.450-461
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• 2006

In this study, sorption kinetics of lead (Pb) and cadmium (Cd) onto coastal sediments were investigated at pH 5.5 using laboratory batch adsorbers. Four different models: one-site mass transfer model (OSMTM), pseudo-first-order kinetic model (PFOKM) ,pseudo-second-order kinetic model (PSOKM) and two compartment first-order kinetic model (TCFOKM) were used to analyze the sorption kinetics. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM, PFOKM and PSOKM in describing sorption kinetics of Pb and Cd onto sediments. Most sorption of Pb and Cd was rapidly completed within the first three hours, followed by slow sorption in the subsequent period of sorption. All models predicted that the sorbed amount at the apparent sorption ($q_{e,s}$) equilibria increased as the CEC and surface area of the sediments increased, regardless of initial spiking concentration ($C_0$) and heavy metal and the sediment type. The sorption rate constant ($k_s,\;hr^{-1}$) in OSMTM also increased as the CEC and BET surface area increased. The rate constant of pseudo-first-order sorption ($k_{p1,s},\;hr^{-1}$) in PFOKM were not correlated with sediment characteristics. The results of PSOKM analysis showed that the rate constant of pseudo-second-order sorption ($k_{p2,s},\;g\;mmol^{-1}\;hr^{-1}$) and the initial sorption rate ($v_{o,s},\;mg\;g^{-1}\;hr^{-1}$) were not correlated with sediment characteristics. The fast sorption fraction ($f_{1,s}$) in TCFOKM increased as CEC and BET surface increased regardless of initial aqueous phase concentrations. The sorption rate constant of fast fraction ($k_{1,s}=10^{0.1}-10^{1.0}\;hr^{-1}$) was much greater than that of slow sorption fraction ($k_{2,s}=10^{-2}-10^{-4}\;hr^{-1}$) respectively.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.49-56
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• 2010

Objective: To investigate assisted reproductive technology (ART) outcomes in women with WHO class I anovulation compared with control group. Design: Retrospective case-control study. Methods: Twenty-three infertile women with hypogonadotropic hypogonadism (H-H) who undertook ART procedure from August 2003 to January 2009 were enrolled in this study. A total of 59 cycles (H-H group) were included; Intra-uterine insemination with super-ovulation (SO-IUI, 32 cycles), in vitro fertilization with fresh embryo transfer (IVF-ET, 18 cycles) and subsequent frozenthawed embryo transfer (FET, 9 cycles). Age and BMI matched 146 cycles of infertile women were collected as control group; 64 cycles of unexplained infertile women for SO-IUI and 54 cycles of IVF-ET and 28 cycles of FET with tubal factor. We compared ART and pregnancy outcomes such as clinical pregnancy rate (CPR), clinical abortion rate (CAR), and live birth rate (LBR) between the two groups. Results: There was no difference in the mean age ($32.7{\pm}3.3$ vs. $32.6{\pm}2.7$ yrs) and BMI ($21.0{\pm}3.1$ vs. $20.8{\pm}3.1kg/m^2$) between two groups. Mean levels of basal LH, FSH, and $E_2$ in H-H group were $0.62{\pm}0.35$ mIU/ml, $2.60{\pm}2.30$ mIU/ml and $10.1{\pm}8.2$ pg/ml, respectively. For ovarian stimulation, H-H group needed higher total amount of gonadotropin injected and longer duration for ovarian stimulation (p<0.001). In SO-IUI cycles, there was no significant difference of CPR, CAR, and LBR between the two groups. In IVF-ET treatment, H-H group presented higher mean $E_2$ level on hCG day ($3104.8{\pm}1020.2$ pg/ml vs. $1878.3{\pm}1197.7$ pg/ml, p<0.001) with lower CPR (16.7 vs. 37.0%, p=0.11) and LBR (5.6 vs. 33.3%, p=0.02) and higher CAR (66.7 vs. 10.0%, p=0.02) compared with the control group. However, subsequent FET cycles showed no significant difference of CPR, CAR, and LBR between the two groups. Conclusion: H-H patients need higher dosage of gonadotropin and longer duration for ovarian stimulation compared with the control groups. Significantly poor pregnancy outcomes in IVF-ET cycles of H-H group may be due to detrimental endometrial factors caused by higher $E_2$ level and the absence of previous hormonal exposure on endometrium.