• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.597-603
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• 1996

This study was carried out to examine degradation characteristics of microalgae Chlorella vulgaris in methane fermentation. We measured COD and VS reduction, gas and methane productivity, VFA (volatile fatty acid), respectively. Then we calculated material balance and hydrolysis rates in soluble and solid material. The substrate concentration was controlled from 14 gCOD$_{cr}$/l to 64 gCOD$_{cr}$/l in batch cultures, and HRT (hydraulic retention time) controlled from 2 days to 30 days in continuous experi- ments. The results were as follows. In batch culture, accumulated gas productivity increased with the increase of the substrate concentration. The SS and VSS was removed all about 30% increase of substrate concentration and the most of the degradable material removed during the first 10 days. The curve of gas and methane production rate straightly increased until substrate concentration is 26 gCOD$_{cr}$/l. In continuous culture experiments, the removal rates at HRT 10days were 20% for total COD and TOC, respectively. At longer HRT, there was no increase in the removal efficiency. At HRT 15 days, the removal rates were 30% for SS and VSS, respectively. Soluble organic materials were rapidly degraded, and so there was no accumulated. Soluble COD concentration was not increase regardless of HRT-increasing. That meaned the hydrolysis was one of the rate-limiting stage of methane fermentation. The first-order rate constants of hydrolysis were 0.23-0.28 day$^{-1}$ for VSS, and 0.07-0.08 day$^{-1}$ for COD.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.134-138
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• 2008

Purpose: In a diabetic foot ulcer, superficial fungal infection of the foot may disrupt the skin integrity and provide an avenue for bacterial infection. The prevalence of fungal infection in diabetic foot ulcer has been reported as 12-30% in Caucasian patients. However, no data are available for Korean patients. The purpose of the study was to examine the prevalence of fungal infection in diabetic foot patients admitted in our clinic. Methods: This study included consecutive 30 diabetic foot ulcer patients(24 males and 6 females) admitted from May 2007 to July 2007. The mean age was 60.5 years. All patients underwent mycological examination including direct microscopic examination in KOH and culturing on slants and tubes with Sabouraud's glucose agar. Results: Clinical signs of presumed fungal infection, which were examined by dermatologists, were found in all patients included in this study. Direct microscopic examination was positive for the specimens of the skin and the toenails in 28(93.3%) and 25(83.3%) patients, respectively. In addition, culture result was positive for the specimens of the skin and the toenails in 5(16.73%) and 7(23.3%) patients, respectively. Conclusion: The prevalence of fungal infection in diabetic foot ulcer patients admitted in our clinic is much higher than that in Caucasian patients(83.3-93.3% vs 12-30%).

• Journal of Chest Surgery
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• v.22 no.2
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• pp.234-245
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• 1989

Between January 1984 and December 1986, sixty nine patients, aged 16 months to 25 years [mean age 10.05*6.40 years], underwent total correction of tetralogy of Fallot in Kyungpook national university hospital. In 66 hospital survivors, 30 patients were followed up for 12 to 48 months [mean 30.10*10.26 months]. These 30 patients were classified in two groups, TAP [transannular patch] and Non-TAP group. There were 9 patients in TAP group, and 21 in Non-TAP group. There were no significant differences between two groups in terms of age at operation, follow up duration, ACC time, and bypass time. All patients were evaluated by two dimensional echocardiography, Doppler echocardiography, standard 12-lead electrocardiography, and plain chest X-ray. Right ventricular systolic pressure, pulmonary arterial systolic pressure, pressure gradient between the right ventricle and the pulmonary artery, presence or absence of pulmonary regurgitation and its grading, fractional shortening of the left ventricle, and Qp/Qs in case of remnant ventricular septal defect were obtained by echocardiographic examination. Cardiothoracic ratio was measured by plain chest film, and ventricular dysrrhythmia was detected by electrocardiogram. Comparing the data between two groups, there was significant difference in incidence of postoperative pulmonary regurgitation [p< 0.05], 100%[9/9] in TAP group and 47.6 %[10/21] in Non-TAP group, but all the regurgitations were not severe. There were no significant differences in other comparisons, despite of higher incidence of cardiomegaly in TAP group [CT ratio: 59.3*5.3% VS 54.7*6, 4 %].

• Environmental Engineering Research
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• v.21 no.1
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• pp.69-73
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• 2016

Generation of food waste is a serious issue that needs to be addressed worldwide. Developing suitable treatment methods while generating energy (methane) is a common practice for sustainable treatment of waste. In this study, methane generation by food waste was investigated in mesophilic and thermophilic regimes at various hydraulic retention times (HRTs) and organic loading rates (OLR). In temperature regimes, influent concentrations and HRTs ranged from 30 to 110 g COD/L and 18 to 30 days, respectively, which corresponding to an OLR of 1.0 to $6.1kg\;COD/m^3-d$. Better methane production and organic removal was observed under thermophilic conditions because of the enhanced hydrolysis of complex polymers and microbial activity at higher temperature. The peak methane productivities attained in thermophilic and mesophilic regimes were 1.30 and $0.99m^3/m^3-d$, respectively. The maximum methane yields were achieved at 50 g COD/L and HRT of 24 d in both cases, and the values were 264 and $221m^3/ton$ COD, respectively. The results of this study will facilitate the development of sustainable methane production technologies using food waste as a feedstock.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.2
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• pp.96-104
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• 2017

Objective: This study aimed to compare the clinical outcomes between in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in sibling oocytes. Additionally, we evaluated whether the implementation of split insemination contributed to an increase in the number of ICSI procedures. Methods: A total of 571 cycles in 555 couples undergoing split insemination cycles were included in this study. Among them, 512 cycles (89.7%) were a couple's first IVF cycle. The patients were under 40 years of age and at least 10 oocytes were retrieved in all cycles. Sibling oocytes were randomly allocated to IVF or ICSI. Results: Total fertilization failure was significantly more common in IVF cycles than in ICSI cycles (4.0% vs. 1.4%, p<0.05), but the low fertilization rate among retrieved oocytes (as defined by fertilization rates greater than 0% but < 30%) was significantly higher in ICSI cycles than in IVF cycles (17.2% vs. 11.4%, p<0.05). The fertilization rate of ICSI among injected oocytes was significantly higher than for IVF ($72.3%{\pm}24.3%$ vs. $59.2%{\pm}25.9%$, p<0.001), but the fertilization rate among retrieved oocytes was significantly higher in IVF than in ICSI ($59.2%{\pm}25.9%$ vs. $52.1%{\pm}22.5%$, p<0.001). Embryo quality before embryo transfer was not different between IVF and ICSI. Although the sperm parameters were not different between the first cycle and the second cycle, split insemination or ICSI was performed in 18 of the 95 cycles in which a second IVF cycle was performed. Conclusion: The clinical outcomes did not differ between IVF and ICSI in split insemination cycles. Split insemination can decrease the risk of total fertilization failure. However, unnecessary ICSI is carried out in most split insemination cycles and the use of split insemination might make ICSI more common.

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.25-30
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• 2000

The relation between the phase-shift profile for the intermediate frequencies and the Langmuir adsorption isotherm at the poly-$Pt/0.1\;M\;H_2SO_4$ aqueous electrolyte interface has been studied using ac impedance measurements, i.e., the phase-shift methods. The suggested interfacial equivalent circuit consists of the serial connection of the electrolyte resistance ($R_S$), the faradaic resistance $(R_F)$ and the equivalent circuit element $(C_P)$ of the adsorption pseudocapacitance $(C_\varphi)$. The delayed phase shift $(\varphi)$ depends on both the cathode potential (E) and frequency (f), and is given by $\varphi=-tan^{-1}[1/2{\pi}f(R_s+R_F)C_p]$. The phase-shift profile $(\varphi\;vs.\;E)$ for the intermediate frequency (ca. 6Hz) can be used as an experimental method to determine the Langmuir adsorption isotherm (9 vs. E). The equilibrium constant (K) for H adsorption and the standard free energy $({\Delta}G_{ads})$ of H adsorption at the poly-$Pt/0.1\;M\;H_2SO_4$ electrolyte interface are $1.8\times10^{-4}\;and\;21.4kJ/mol$, respectively. The H adsorption is attributed to the over-potentially deposited hydrogen (OPD H).

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.476-477
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• 2013

반도체의 성능은 최근 10년 사이에 급격하게 발전했고 아날로그 및 디지털 회로 소자들에 있어 저전력/고속 특성 요구가 커지고 있다 [1]. 상온에서 30,000 $cm^2$/Vs 이상의 전자 이동도를 가지며 큰 conduction band offset을 갖는 InAs/AlSb 2차원전자가스(2DEG) 소자는 Spinorbit-interaction의 값이 매우 커서 SPIN-FET 소자로 크게 주목받고 있다 [2]. 본 발표자들은 GaAs 기판위에 성장한 InAs 2DEG HEMT 소자의 전/자기적인 특성과 고속반응 물질로 주목 받는 InSb 박막소자의 doping 특성에 따른 전기적/물리적인 특성의 평가에 대해 그 결과를 소개하고자 한다. 격자정합과 Semi-insulating 기판의 부재로 상용화되어 있는 GaAs와 InP 기판위에 물질차이에 따른 고유의 한계 특성을 줄이기 위한 Pseudomorphic이라 불리는 특별한 박막 성장 기법을 적용하여 높은 전자 이동도를 가지며 spin length가 길어 Spin-FET로서 크게 주목받고 있는 InAs 2DEG HEMT 소자를 완성시켰다. 60,000 ($cm^2$/Vs) 이상의 높은 전자 이동도를 갖는 소자의 구현을 목표로 연구를 진행하였으며 1.8 K에서 측정된 Spin-orbit interaction의 값은 6.3e-12 (eVm)이다. InAs/InGaAs/InAlAs 및 InGaAs/InAlAs 구조의 InP 기반의 소자에서 보다 큰 값으로 향후 Spin-FET 응용에 크게 기대하고 있다. 또한, GaAs 기판위에 구현된 InSb 소자는 격자부정합 감소를 위해 InAs 양자점을 사용하여 약 $2.6{\mu}m$ 두께로 구현된 InSb 박막 소자는 상온에서 약 60,400 ($cm^2$/Vs)의 상온 전자이동도를 보였으며 현재 동일 두께에서 세계 최고결과(~50,000 $cm^2$/Vs)에 비해 월등하게 높은 값을 보이고 있다. Hall bar pattern 공정을 거쳐 완성된 소자는 측정 결과 10~20% 이상 향상된 전자 이동도를 보였다. 2e18/$cm^3$ 미만의 p-doping의 경우, 상온에서 n-type 특성을 보이나, 저온에서 p-type으로 변하는 특성을 보였고 n-doping의 경우 5e17/$cm^3$까지는 전자 이동도만 감소하고, doping에 의한 효과는 크게 없었다. 1e18/$cm^3$의 높은 doping을 할 경우 carrier가 증가하는 것을 확인했다. 이상의 측정 결과로 Spin-FET 소자로서 아주 우수하다는 것을 확인할 수 있었고 n-/p- type이 특성을 고려한 high quality InSb 박막소자의 응용을 위한 중요한 정보를 얻을 수 있었다.

• Clinical and Experimental Reproductive Medicine
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• v.32 no.4
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• pp.331-336
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• 2005

Objective: To investigate the effects of female age on in vitro maturation and fertilization of immature oocytes from controlled ovarian hyperstimulation (COH) in human IVF-ET program. Method: A total of 96 immature oocytes (GV & metaphase I) obtained from 40 cycles of IVF-ET (29 patients). The mean age of female patients was $31.8{\pm}3.1years$. Ovulation was triggered by urinary or recombinant hCG. Immature oocytes were cultured with YS medium containing 30% of patients' human follicular fluids, LH (1 IU/mL), FSH (1 IU/mL) and EGF (10 ng/mL), and then matured oocytes were fertilized by ICSI. In vitro maturation and fertilization of immature oocytes were analyzed according to age of female (< 34 or ${\geq}34years$). Results: The maturation rate was similar between two groups (68% vs 64%). The fertilization rate of in?vitro-matured oocytes was higher in patients < 34 years old, but there was no statistical significance (64% vs 50%, p=0.347). The fertilization rate of in-vitro-matured oocytes was significantly lower compared with those of in-vivo-matured oocytes in both age groups (64% vs 79%, p=0.035, 50% vs 86%, p=0.007). Conclusion: In older female group, fertilization rate of in-vitro-matured oocytes seems to be decreased. Further investigations should be warranted to increase fertilization potential of in-vitro-matured oocytes.

• Radiation Oncology Journal
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• v.32 no.3
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• pp.147-155
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• 2014

Purpose: This study was conducted to observe the outcomes of postoperative radiotherapy (PORT) with or without concurrent chemotherapy in resected non-small cell lung cancer (NSCLC) in single institution. Materials and Methods: From 2002 to 2013, 78 patients diagnosed with NSCLC after curative resection were treated with radiotherapy alone (RT, n = 48) or concurrent chemoradiation (CCRT, n = 30). The indications of adjuvant radiation therapy were N2 node positive (n = 31), close or involved resection margin (n = 28), or gross residual disease due to incomplete resection (n = 19). The median radiation dose was 57.6 Gy (range, 29.9 to 66 Gy). Results: Median survival time was 33.7 months (range, 4.4 to 140.3 months). The 5-year overall survival (OS) rate was 49.5% (RT 46% vs. CCRT 55.2%; p = 0.731). The 3-year disease-free survival rate was 45.5% (RT 39.4% vs. CCRT 55.3%; p = 0.130). The 3-year local control rate was 68.1% (RT 64.4% vs. CCRT 77.7%; p = 0.165). The 3-year DMFS rate was 56.1% (RT 52.6% vs. CCRT 61.7%; p = 0.314). In multivariate analysis, age ${\geq}66$ years and pathologic stage III were significant poor prognostic factors for OS. Treatment failure occurred in 40 patients. Four patients had radiologically confirmed grade 3 radiation pneumonitis. Conclusion: In NSCLC, adjuvant RT or CCRT after curative surgery is a safe and feasible modality of treatment. OS gain was seen in patients less than 66 years. Postoperative CCRT showed a propensity of achieving better local control and improved disease-free survival compared to RT alone according to our data.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.589-594
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• 2013

Background: Prospective cohort studies to determine cofactors with oncogenic HPV-infections for cervical cancer are very rare from developing countries and such data are limited to the few screening trials. Large screening trials provide such data as a by product. Some of the cases are prevented by screening and do not surface as invasive cancers at all. Also, pre-invasive lesions are detected almost entirely by screening. Screening causes selection bias if attendance in or effectiveness of screening is correlated with the risk factors. The aim of this study was to quantify the influence of screening on risk factors for cervical cancer. Materials and Methods: Our material stems from a rural cohort of 80,000 women subjected to a randomised screening trial. The effect of screening on the incidence of cervix cancer was estimated with reference to socio-demographic and reproductive risk factors of cervical cancer. We compared these risks with the incidence of cancer in the randomised control population by the same determinants of risk. Results: The results in the screening arm compared to the control arm showed that the women of low SES and young age were benefitting more than those of high SES and old age. The relative risk by age (30-39 vs 50-59) was 0.33 in the control arm and 0.24 in the screening arm. The relative risk by education (not educated vs educated) was 2.8 in the control arm and 1.8 in the screening arm. The previously married women did not benefit (incidence 113 and 115 per 100,000 women years in control vs screening arms) whereas the effect was substantial in those married (86 vs 54). Conclusions: The results in controls were consistent with the general evidence, but results in attenders and nonattenders of the screening arm showed that screening itself and self-selection in attendance and effectiveness can influence the effect estimates of risk factors. The effect of cervical cancer screening programmes on the estimates of incidence of cervical cancer causes bias in the studies on etiology and, therefore, they should be interpreted with caution.