• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.87-97
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• 1995

Acute and chronic toxicity of phenol on the mortality, long-term survival and respiration rates of the mysid, Archaeomysis kokuboi adult and juvenile were examined. This experiment was condurted by static bioassay procedure with the different salinity at $25^{\circ}C$ In lethal test, the test animals were exposed to 6 different phenol concentrations to determine $LC_{50}$ and I$LT_{50}$ (median lethal concentration and time) values. The $LC_{50}$ values with the exposure time for the mysid adult ranged from 31.31ppm to 1.49ppm phenol and for the mysid juvenile ranged from 6.90ppm to 0.26ppm in all experimental groups. Mortality was increased with the decrease of salinity, The $96hr-LC_{50}$ values at 16, 24 and $32\%o$ salinity for the mysid adult were 1.49, 2.71 and 4.53ppm phenol, white the values for the mysid juvenile were 0.26, 0.56 and 0.71ppm, respectively. The ratios of $96hr-LC_{50}$ values for the mysid adult to those for the mysid juvenile at 16, 24 and $32\%p$ salinity were 5.73, 4.84 and 6.38, respectively. The mysid juveniles were more sensitive to phenol than the mysid adults. Compared $LT_{50}$ values for the mysid adult with those for the mysid juvenile, the $LT_{50}$ values for the mysid adult ranged from 384.7 to 29.0 hours at 1.7-127ppm phenol concentrations and for the mysid juvenile ranged from 132.2 to 18.7 hours at 0.5~6.Oppm phenol concentrations. The lowest $LT_{50}$ values for the mysid adult and juvenile were showed at the combination of the highest experimental concentration of phenol and the lowest experimental salinity. The mysid juveniles showed lower $LT_{50}$ values than those of adults. The chronic effects of phenol on the mysid at the sublethal effective concentration of phenol were lower in the $32\%o$ salinitr group than 16 or $24\%o$ salinity groups. Oxygen consumption rates of the mysid adult were decreased with the increase of phenol concentration and exposure time, and decreased significantly in lower salinity at the same concentration or phenol.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.5 no.4
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• pp.1-34
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• 2010

Recently, failure rates of Kosdaq IPO firms are increasing and their survival rates tend to be very low, and when these firms do fail, often times backed by a number of governmental financial supports, they may inflict severe financial damage to investors, let alone economy as a whole. To ensure investors' confidence in Kosdaq and foster promising and healthy businesses, it is necessary to precisely assess their intrinsic values and survivability. This study investigates what contributed to the failure of IPO firms and analyzed how these elements are factored into corresponding firms' stock returns. Failure risks are assessed at the time of IPO. This paper considers factors reflecting IPO characteristics, a firm's underwriter prestige, auditor's quality, IPO offer price, firm's age, and IPO proceeds. The study further went on to examine how, if at all, these failure risks involved during IPO led to post-IPO stock prices. Sample firms used in this study include 98 Kosdaq firms that have failed and 569 healthy firms that are classified into the same business categories, and Logit models are used in estimate the probability of failure. Empirical results indicate that auditor's quality, IPO offer price, firm's age, and IPO proceeds shown significant relevance to failure risks at the time of IPO. Of other variables, firm's size and ROA, previously deemed significantly related to failure risks, in fact do not show significant relevance to those risks, whereas financial leverage does. This illustrates the efficacy of a model that appropriately reflects the attributes of IPO firms. Also, even though R&D expenditures were believed to be value relevant by previous studies, this study reveals that R&D is not a significant factor related to failure risks. In examing the relation between failure risks and stock prices, this study finds that failure risks are negatively related to 1 or 2 year size-adjusted abnormal returns after IPO. The results of this study may provide useful knowledge for government regulatory officials in contemplating pertinent policy and for credit analysts in their proper evaluation of a firm's credit standing.

• Radiation Oncology Journal
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• v.8 no.2
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• pp.189-198
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• 1990

Sixty-six patients with squamous cell carcinoma of the oropharynx were treated with radiation therapy and retrospectively analyzed to evaluate the treatment result in the Department of Therapeutic Radiology, Korea Cancer Center Hospital between January 1980 and December 1986. There were 42 patients with carcinoma of the tonsil including the fossa and pillar, 9 patients with carcinoma of the base of tongue,12 patients with carcinoma of the soft palate, and 3 patients with carcinoma of the posterior and lateral pharyngeal walls. Considering all oropharyngeal sites of involvement together, response rates for T1, T2, T3, and T4 were 80%, 77%, and 40%, respectively, with a overall response rate of 70%. The response rate for N1, N2, and N3 were 69%, 63%, and 40%, respectively, with the overall regional response rate of 70%. In lower T status, undifferentiated carcinoma and primary tumor arising from the soft palate, higher response rates were obtained. The S year overall and disease-free survival rate were 56%, 55%, respectively. A better prognosis was obtained in early T stage (T1+T2) (p<0.01) and in patients without tumor extension into adjacent structures in carcinomas arising from tonsillar area (p<0.01). Through this study we suggest that, in terms of anatomical and functional preservation, radiation therapy seems to be an effective method for the primary treatment of patients with oropharyngeal carcinoma.

• Journal of Chest Surgery
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• v.30 no.10
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• pp.979-985
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• 1997

Between October 1991 and May 1995, 256 "New Duromedics Valve"(Edward TEKNA Bileaflet Valve) were implanted in 208 adult patients(171 mitral, 82 aortic and 3 tricuspid) with age ranging from 18 years to 70 years(mean 48.2$\pm$ 11.6 years). Postoperative complication rates were 12.2%, but there was none valve related one. Overall early mortality rate were 1.4%(1.6% for MVR, 2.1% for DVR, and none for AVR or TVR) respectively. Follow-up was 99% completed ranging in duration from 2 months to 46 months. There were 6 valve-related late complications(2.9%) with 2 patients with upper gastrointestinal bleeding, 2 with cerebral thxomtioembolism, 1 with valve thrombosis and 1 with valve endocarditis. Freedom from these valve-related major complications were 89.9% at 40 months. There were 5 late deaths(2.4%). one of these late deaths was considered valve-related. Overall actuarial survival rates at 40 months were 95.5%, 96.8% for mitral, 97.1% for aortic, 100% for tricuspid, and 92.0% for double valve replacement respectively. Preoperative New York Heart Association functional class were 2.9, and 1.3 in post-operative state. We have been trying to keep the international normalized ratio(INR) with range of 2.5 to 3.0. The INR of 4 patients of 5 with anticoagulant ralated complications was beyond the range. To reduce the rate of anticoagulant related complications, we felt very strongly that the INR should be kept between 2.5 and 3.0. In our cases, there was no structural failure or significant hemolysis in the absence of periprosthetic leak. This experience encourages us to continue using the "New Duromedics Valve".omedics Valve".uot;.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.14-20
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• 2014

This study is aimed to search the possibility of developmental toxicity test using the zebrafish from the pesticide. We selected herbicides alachlor and butachlor, reported for fish toxicity, and insecticide fipronil reported for the high fish toxicity and the honey bee risk among the pesticides with high usability for the examples of the pesticides in this experiment. In this study, we showed those effects on the zebrafish embryo development by exposing different kinds of pesticide with different concentration and exposed time periods. As a result, the rates of hatching and abnormality of the zebrafish embryo after treatments of alachlor were increased in 24-48 hpf group, and the juvenile fishes in every group exposed to $40{\mu}M$ or more of alachlor displayed sever morphological changes such as bent tails, edema and activity failures. In case of the butachlor, the rates of hatching and the abnormality in 24-48 hpf group were higher than the other groups exposed in different time periods. The fatality before hatching was high in $40{\mu}M$ or more of butachlor treatment, and entire zebrafish embryos in 48 hpf group died before hatching. All the living juvenile fishes showed morphological changes as like as the treatment of alachlor. The rate of hatching and the survival of the zebrafish embryo by the fipronil were higher than other pesticides. However, morphological changes such as bent tails were observed from the most of living juvenile fishes. Therefore, the effects of three different pesticides with different concentrations and exposing time periods on the development of zebrafish embryos showed that all the pesticides effects were proportional to the concentration, and exposing time periods may cause the morphological abnormality.

• The Korean Journal of Malacology
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• v.17 no.1
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• pp.35-44
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• 2001

This research was conducted to develop seedling production techniques in flat oyster, Ostrea dense lamellosa. The cultivation of larvae, artificial spat and spats collection in natural conditions rate were examined. In the mass culture tank (3 tons), average growth rates of the D Shape larvae of initial shell length (153.4 ㎛) and shell height (153.4 ㎛) were 202.6% and 212.9% at 16 days and 227.1%, 241.8% at 20 days, respectively. Instantaneous death and survival rate of the larvae were 0.160 and 54.8% at 16 days and 0.057 and 43.2% at 20 days, respectively. Collection rate of flat oyster from bottom using various collectors with oyster shell, scallop shell, ark shell and PVC plates were 32.9%, 24.1%, 16.8% and 10.0%, respectively. and the greatest collecting rate was 131.9 individuals/shell (32.9%) in laid collectors on the bottom. The collecting rate of the oyster larvae were better in laid collectors on the bottom 83.8 individuals/collection than in the suspended string 54.2 individuals/collection. in all collecting substrates. Early spats settled on collectors were grew to 2.38 $\pm$ 0.97 ㎜ in shell length and 2.16 $\pm$ 0.86 ㎜ In shell height at 26 days. The spats were grew to 28.58 $\pm$ 2.39 ㎜ in shell length and 31.65 $\pm$ 2.03 ㎜ in shell height during the 4 month mid-term cultivation. In the period of cultivation, the mean number of spats attached to collectors were 10.3 individuals at oyster shells, 5.8 scallop shells, 4.0 ark shells and 1.5 PVC plates, respectively.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.249-259
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• 2014

Cryopreserving cells which are maintaining their viability are the very complex process. This study has been carried out in order to find the effects of cryopreservation steps and freezing media on the rates of viability of cryopreserved chicken primordial germ cells (PGCs). PGCs obtained from the germinal gonade of 5.5~6 day (stage 28) chick embryos of Korean Ogye (KO) and Commercial breeds (C), using the MACS method were suspended in a freezing medium containing a freezing and protecting agents (e.g. dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PG)). Gonads were harvested from stage 28 chick embryos and pooled in groups of 5, 10, 15, 20E embryos, contributing gonads to the cell suspension. The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments : 2.5%, 5%, 10%, 15% and 0% cryoprotectant (DMSO, EG, PG) as a control. Effects of exposure to slow freezing and vitrification, with different concentrations of the cryoprotectant solution, were examined. After vitrification and slow freezing, survival rates of the frozen-thawed PGCs from the 10% EG plus FBS treatment were 85.63%, and 66.14% (p<0.05), respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% PG + FBS treatment (p<0.05) (85.63% vs 66.81%) by vitrification. This study established a method for preserving chicken PGCs that enables systematic storage and labeling of cryopreserved PGCs in liquid ($LN_2$) at a germplasm repository and ease of entry into a data base. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.295-302
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• 2009

Purpose : To report our experience of gastrointestinal (GI) operations (OP) performed in very low birth weight infants (VLBWI) and to evaluate their clinical characteristics. Methods : Among the 1,117 VLBWI admitted to the SMC neonatal intensive care unit from November 1994 to February 2007, the medical records of 37 infants who underwent GI OP (except inguinal hernia OP) and 1,080 VLBWI without GI OP were retrospectively reviewed. Results : The mean gestational age ($27^{+6}2^{+3}$ vs. $28^{+5}{\pm}$2^{+6}$) and birth weight (979${\pm}$241 g vs. 1,071${\pm}$271 g) of the 37 VLBWI who underwent the GI OP was lower than the VLBWI without GI OP group (n=1,080). Mortality rates in the GI OP group were significantly higher than in the non GI OP group (28% vs. 15%, P<0.001). The incidence of cholestasis, retinopathy of prematurity and periventricular leukomalacia were higher in the GI OP group than in the non GI OP group, but the incidence of bronchopulmonary dysplasia was not significantly different between the GI OP group and the non GI OP group. For GI OP indications, focal intestinal perforation was most common and showed a more favorable outcome than necrotizing enterocolitis. Compared with an earlier 7-year period, 1994-2000, the incidence and survival rates increased in the subsequent 2001-2007 period. Conclusion : GI OP was associated with high mortality and morbidity in VLBWI. Further efforts to improve outcomes of GI OP in VLBWI should be investigated to improve the quality of care in VLBWI.

• Korean Journal of Animal Reproduction
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• v.22 no.1
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• pp.1-9
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• 1998

This study was carried out to confirm whether the developmental capacity of bovine mature oocytes frozen ultra-rapidly using electron microscopic(EM) grids and EFS30 can be obtained, and whether the cryoprotectants and the freezing method used in this study effect detrimentally to the bovine oocytes by indirect immunocytochemistry. As freezing solution, we used EFS30 which consisted of 30% ethylene glycol, 0.5 M sucrose, 18% ficoll and 10% FBS added in D-PBS. The results obtained in this experiment were summarized as follows: When the effects of cryoprotectant and freezing procedure on the microtuble, micrfilament and chromatin morphology of oocytes were evaluated using indirect immunocytochemistry, the results of freezing as well as exposure group were not different with that of the control oocytes. When the fertilization abnormality after ultrarapid freezing of bovine mature oocytes was examined by Hoechst staining, the rates of total penetration(96.7, 9.0%), normal two pronuclei formation(74.6, 68.9%) and mean number of sperm / oocyte(1.50, 1.44) were not different between control and freezing group. In addition, when the developmental capacity of frozen-thawed of oocytes(85.5%) was survived, 74.5% of them were cleaved and 31.4% of cleaved embryos were developed to blastocyst. These data were similar to those of the control(76.0%, 34.6%) and exposure(74.5%, 33.0%) except survival rates. Also, when the total cell number of blastocysts produced from the each treatment at day after IVF was examined by hoechst staining, there were not different among groups. There results demonstrate that developmental capacity of frozen-thawed bovine mature oocytes can be successfully obtained by ultra-rapid freezing method using EM grid and EFS30 solution.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.317-322
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• 1996

Purpose : Patients with cervical cancer who have positive resection margins after radical hysterectomy are at increased risk for local recurrence. The result of postoperative pelvic radiotherapy for cervix cancer with positive resection margins were analyzed to evaluate the role of radiotherapy. Materials and Methods : Between n 1979 and 1992, 60 patients of cervix carcinoma were treated with postoperative radiotherapy after radical hysterectomy and pelvic lymphadenectomy because of positive vaginal (48 patients) or parametrial resection margins (12 patients). Patients were treated with external beam radiation therapy (EBRT) alone (12 Patients) or EBRT plus vaginal ovoid irradiation (VOI) (48 patients). The median followup period was 55 months. Results : The 5-year actuarial disease free and overall survival rates for all patients were $75.2\%$, $84.1\%$, respectively. The overall recurrence rate was $23\%$ (14/60). In 48 patients with Positive vaginal resection margins, the pelvic recurrence was $8\%$ (4/48). Distant metastasis was $15\%$(7/48). Of the 43 patients with positive vaginal resection margins treated with EBRT and VOI, recurrence rate was $21\%$(9/43) , while recurrence rate was $40\%$(2/5) in the EBRT only treated group. In 12 patients with positive parametrial margins, three patients ($25\%$) had distant metastases. The most significant prognostic factor was lymph node metastasis. Complications resulting from radiotherapy occurred at a rate of $32\%$(19/60) and grade III complications occurred in three patients ($5\%$). Conclusion : Postoperative radiotherapy can produce excellent pelvic control rates in patients with positive resection margins. In patients with positive vaginal margins, whole pelvic EBRT and VOI is recommended.