• Journal of Life Science
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• v.29 no.1
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• pp.76-83
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• 2019

In this study, the optimal growth and poly(3-hydroxybutyrate) (PHB) biosynthesis of Pseudomonas sp. EML2 were established using waste frying oil (WFO) as a cheap carbon source. The fatty acid composition of WFO and fresh frying oil (FFO) were analyzed by gas chromatography. The unsaturated and saturated fatty acid contents of the FFO were 82.6% and 14.9%, respectively. These contents changed in the WFO. The compositional change in the unsaturated fatty acid content in the WFO was due to a change in its chemical and physical properties resulting from heating, an oxidation reaction, and hydrolysis. The maximum dry cell weight (DCW) and PHB yield (g/l) of the isolated strain Pseudomonas sp. EML2 were confirmed under the following culture conditions: 30 g/l of WFO, 0.5 gl of $NH_4Cl$, pH 7, and $20^{\circ}C$. Based on this, the growth and PHB yield of Pseudomonas sp. EML2 were confirmed by 3 l jar fermentation. After the cells were cultured in 30 g/l of WFO for 96 h, the DCW, PHB content, and PHB yield of Pseudomonas sp. EML2 were 3.6 g/l, 73 wt%, and 2.6 g/l, respectively. Similar results were obtained using 30 g/l of FFO as a carbon source control. Using the FFO, the DCW, PHB content, and PHB yield were 3.4 g/l, 70 wt%, and 2.4 g/l, respectively. Pseudomonas sp. EML2 and WFO may be a new candidate and substrate, respectively, for industrial production of PHB.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.1
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• pp.8-15
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• 2021

TiO2 has been used in various fields such as solar cells, dental implants, and photocatalysis, because it has high physical and chemical stability and is harmless to the body. TiO2 nanofibers which have a large specific surface area also show a good reactivity in bio-friendly products and excellent photocatalysis in air and water purification. To fabricate TiO2 nanofibers, an electrospinning method was used. To observe the diameter of TiO2 nanofibers with fabrication variables, the fabrication variables was divided into precursor composition variables and process variables and microstructure was analyzed. The concentrations of PVP (Polyvinylpyrrolidone) and TTIP (Titanium(IV) isopropoxide) were selected as precursor composition variables, and inflow velocity and voltage were also selected as process variables. Microstructure and crystal structure of TiO2 nanofibers were analyzed using FE-SEM (Field emission scanning electron microscope) and XRD (X-ray diffraction), respectively. As-spun TiO2 nanofibers with an average diameter of about 0.27 ㎛ to 1.31 ㎛ were transformed to anatase TiO2 nanofibers with an average diameter of about 0.22 ㎛ to 0.78 ㎛ after heat treatment of 3 hours at 450℃. Anatase TiO2 nanofibers with an average diameter of 0.22 ㎛ can be expected to improve the photocatalytic properties by increasing the specific surface area. To change the average diameter of TiO2 nanofibers, the control of precursor composition variables such as concentrations of PVP and TTIP is more efficient than the control of electrospinning process variables such as inflow velocity and voltage.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.2
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• pp.101-109
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• 2022

The mobility and transport of radioactive cesium are crucial factors to consider for the safety assessment of high-level radioactive waste disposal sites in granite. The retardation of radionuclides in the fractured crystalline rock is mainly controlled by the hydrochemical condition of groundwater and surface reactions with minerals present in the fractures. This paper reports the experimental results of cesium sorption to the Wonju Granite, a typical Mesozoic granite in Korea, performed in an anaerobic chamber that mimics the anoxic environment of a deep disposal site. We measured the rates and amounts of cesium (¹³³Cs) removed by crushed granite samples in different electrolyte (NaCl, KCl, and CaCl₂) solutions and a synthetic groundwater solution, with variations in the initial cesium concentration (10^-5, 5×10^-6, 10^-6, 5×10^-7 M). The cesium sorption kinetic and isotherm data were successfully simulated by the pseudo-second-order kinetic model (r²= 0.99) and the Freundlich isotherm model (r²= 0.99), respectively. The sorption distribution coefficient of granite increased almost linearly with increasing biotite content in granite samples, indicating that biotite is an effective cesium scavenger. The cesium removal was minimal in KCl solution compared to that in NaCl or CaCl₂ solution, regardless of the ionic strength and initial cesium concentration that we examined, showing that K⁺ is the most competitive ion against cesium in sorption to granite. Because it is the main source mineral of K⁺ in fracture fluids, biotite may also hinder the sorption of cesium, which warrants further research.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.491-501
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• 2022

Bentonite has been proposed as a buffer and backfill material for high-level radioactive waste repository. Under such repository environment conditions, bentonite is subjected to combined thermal, hydrological, mechanical, and chemical processes. This study evaluates the feasibility of applying X-ray CT technology on the characterization of bentonite under hydration conditions using a newly developed testing cell. The cylindrical cell is made of platic material, with a removable cap to place the sample, enabling to apply vertical pressure on the sample and to measure swelling pressure. The hydration test was carried out with a sample made of Gyeonju bentonite, with a dry density of 1.4 g/cm³, and a water content of 20%. The sample had a diameter of 27.5 mm and a height of 34 mm. During the test, water was injected at a constant pressure of 0.207 MPa, and lasted for 7 days. After one day of hydration, bentonite swelled and filled out the space inside the cell. Moreover, CT histograms showed how the hydration process induced an initial increase and later progressive decrease on the density of the sample. Detailed profiles of the mean CT value, CT standard deviation, and CT gradient provided more details on the hydration process of the sample and showed how the bottom and top regions exhibited a decrease on density while the middle region showed an increase, especially during the first two days of hydration. Later, the differences in CT values with respect to the initial state decreased, and were small at the end of testing. The formation and later reduction of cracks was also characterized through CT scanning.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.71-81
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• 2009

Food waste has been actively used as a composting material in order to reduce the environmental pollution load and to enhance the recycling of resources. In this study, the longterm effects of continuous application of food waste compost to soils on both the crop production and the soil properties were examined to ensure the safety of food waste compost in agricultural use. In addition, we collected the preliminary data for establishing standard application rate of food waste compost for agricultural utilization. Based on conventional nitrogen application rate of chemical fertilizer for crop cultivation, pig manure compost $(24g\;N\;kg^{-1}$, $8g\;P_2O_5\;kg^{-1}$, and $10.4g\;K_2O\;kg^{-1})$ and food waste compost ($20g\;N\;kg^{-1}$, $20.1g\;P_2O_5\;kg^{-1}$, and $6.5g\;K_2O\;kg^{-1}$) were applied to the upland soil in $2{\times}2{\times}2m$ lysimeter in which lettuce (Lactuca sativa var. crispa), Chinese cabbage (Brassica campestris subsp. napus var. pekinensis), red pepper (Capsicum annuum), and potato (Solanum tuberosum) were grown continuously. The crops grown in soils to which food waste compost applied showed better growth responses than the control, whereas some variations were observed in the crops grown in chemical fertilizer treated soils. Continuous application of food waste compost increased the contents of organic matter, nitrogen, and phosphorus, which resulted in improving soil aeration.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.872-886
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• 2010

Six kinds of sunsik containing different contents of brown rice(BR; 20, 30, and 50%) were prepared and subjected to various processing conditions(with or without roasting at $200^{\circ}C$ for 20 min e.g., designated as RBR50 or BR50) to assess their functionality as ready-to-eat foods. They were also assessed for their nutritional and sensory properties and oxidative stability. Dietary fiber contents were proportionate to the levels of added BR. Protein was highest in RBR50 (p<0.001), which also had the highest amounts of free and structural amino acids. The amount of free amino acids tended to increase with roasting, although most amino acids were present in structural form. Oleic acid and linoleic acid were the predominant fatty acids in all prepared sunsik, and RBR50 presented noticeably higher peroxidability index due to its higher amount of linoleic acid(p<0.05). Nevertheless, RBR50 showed good oxidative stability; this phenomenon was observed in all sunsik with roasted BR but not in those with non-roasted BR. It is implied that potential antioxidants might have been newly formed or converted from their precursors while BR was roasted. Roasting process also had an impact on the sensory properties of sunsik, e.g., sunsik with added roasted BR showed lower dissolution and darker color intensity compared to its counterpart sunsik.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.350-359
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• 2001

The purpose of this study is to develop theme-based integrated science unit by the interdisciplinary approach and to analyze it's effects on the science achievement and the attitude towards science learning. 'Interaction' and 'Stability' were selected as the integrated themes, and the main concept and subconcept in relation to the themes were extracted from the four areas of science, and the learning contents were constructed in the integrated ways. While the main concept have relevance to subconcept in the interaction, the main concept have little relevance to subconcept in the stability. Therefore, the stability was to fit with middle school integrated science theme, but the interaction was not. The theme-based integrated science units developed was implemented in middle school, and the results are follows. First, the science achievement of group of theme-based integrated science teaching is significantly higher than those of group of traditional teaching. Second, the scores of the test of attitude toward science learning of the group of theme-based integrated science teaching is significantly higher than those of group of traditional teaching. Third, the students' perception of theme-based integrated science teaching was positive. The students have participation, interest, motivation in theme-based integrated science teaching, and students have difficulty in learning theme-based integrated science teaching.

• Radiation Oncology Journal
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• v.18 no.1
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• pp.27-31
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• 2000

Purpose : The aim of this study was to investigate treatment results, toxicity and efficacy of hypefractionated radiation therapy combined with paclitaxel for paraaortic node recurrence in cervix cancer. Materials and Methods: Between September 1997 to March 1999, 12 patients with paraaortic node recurrence in cervix cancer who previously received radical or postoperative radiotherapy were treated with hypefractionated radiation therapy combined with paclitaxel. Of these, 2 patients who irradiated less than 30 Gy were excluded, 10 patients were eligible for this study. Median age was 51 years. Initial FIGO stage was 1 stage IBI, 2 stage IIA, 7 stage IIB. For initial treatment, 7 patients received radical radiotherapy and 3 received postoperative radiotherapy. The paraaortic field encompassed the gross recurrent disease with superior margin at T12, and inferior margin was between L5 and S1 with gap for previously pelvic radiation field. The radiation field was initially anterior and posterior opposed field followed by both lateral field. The daily dose was 1.2 Gy, twice daily fractions, and total radiotherapy dose was between 50.4 and 60 Gy(median, 58.8 Gy). Concurrent chemotherapy was done with paclitaxel as a radiosensitizer. Dose range was from 20 mg/m$^{3}$ to 30 mg/m$^{3}$ (median, 25 mg/m$^{3}$), and cycle of chemotherapy was from 3 to 6 (median, 4.5 cycle). Follow-up period ranged from 3 to 21 months. Results : Interval between initial diagnosis and paraaortic node recurrence was range from 2 to 63 months (median, 8 months). The 1 year overall survival rate and median survival were 75$\%$ and 9.5 months, respectively. The 1 year disease free survival rate and median disease free survival were 30$\%$ and 7 months, respectively. At 1 month after treatment, 4 (40$\%$) achieved a complete response and 6 (60$\%$) experienced a partial response and all patients showed response above the partial response. There was distant metastasis in 6 patients and pelvic node recurrence In 2 patients after paraaortic node irradiation. There was 2 patients with grade 3 to 4 leukopenla and 8 patients with grade 1 to 2 nausea/ vomiting which was usually tolerable with antlemetic drug. There was no chronic complication in abdomen and pelvis during follow up period. Conclusion : hypefractionated radiation therapy combined with paclitaxel chemotherapy diosensitizer showed high response rate and few complication rate in paraaortic node recurrence in cervix cancer Therefore, present results suggest that hypefractionated radiation therapy combined with paclitaxel chemotherapy can be used as optimal treatment modality in this patients.

• Radiation Oncology Journal
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• v.15 no.4
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• pp.369-377
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• 1997

Purpose : This study was Performed to identify the histopathologic feature by the reevaluation of the Pathologic specimen of the cervical tumors and to evaluate the clinical findings and the treatment results of the patients with small cell carcinoma of the cervix treated by radiotherapy. Materials and Methods : 2890 patients with cervical carcinoma received radiotherapy at the Department of Radiation Oncology. Yonsei Cancer Center, Yonsei University College of Medicine between October 1981 and April 1995. Of the 2890 patients in this data base, sixty were found to have small cell carcinomas $(2.08\%)$. Among them thirty six patients were transferred from other hospitals. the biopsy specimens of those Patients were not available. So we could review the slides of the other twenty four patients who were diagnosed at our hospital. Twenty four patients with small cell carcinoma of the cervix were analyzed retrospectively based on the assessment of H & E staining and other four immunohistochemical stains for neuroendocrine differentiation (neuron specific enolase, chromogranin. synaptophysin and Grimelius stain). And we also evaluate the Patients and tumor characteristics. response to radiation. patterns of failures, 5 year overall and disease free survival rates. Results : Thirteen tumors were neuroendocrine carcinomas(13/24 = $54.2\%$) and eleven tumors were squamous carcinomas, small cell type (11/24 = $47.8\%$) based on the assessment of H & E staining and other four neuroendocrine marker studies. So we classified the Patients two groups as neuroendocrine carcinoma and small cell type of squamous carcinoma, Among the 13 neuroendocrine carcinomas, five were well to moderately differentiated tumors and the other eight were Poorly differentiated or undifferentiated ones. The median age was 54 years old (range 23-79 years). Eight Patients had FIGO stage IB disease, 12 had stage 11, 3 had stage III and one had stage IV disease, Pelvic lymph node metastases were found in five Patients $(20.8\%)$. three of them were diagnosed by surgical histologic examination and the other two were diagnosed by CT scan. There was no difference between two histopathologic groups in terms of patients and tumor characteristics. response to radiation. 5 year overall and disease free survival rates. However the distant metastases rate was higher in neuroendocrine carcinoma Patients (6/13:$46.2\%$) than in small cell type of squamous carcinoma Patients (2/11:$18.2\%$), but there was no statistically significant difference because of the small number of patients (P>0.05). Conclusion : More than half of the small cell carcinoma of the cervix patients were neuroendocrine carcinoma (13/24 : $54.1\%$) by reevaluation of the biopsy specimen of the cervical tumors. The tendency of distant metastases of the neurolndocrine carcinoma was greater than those of the small cell type of squamous carcinoma $(46.2\%\;vs.\;18.2\%)$. But there were no differences in the patients and tumor characteristics and other clinical treatment results in both groups. These data suggest that radical local treatment such as radiotherapy or radical surgery combined with combination systemic cytotoxic chemotherapy might provide these patients with the best chance for cure.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.4
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• pp.235-244
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• 1976

Following results are obtained by re-evaluating N. P. K. and soil improvement trials conducted from 1964 to 1969 in valley paddy soils in rolling lands (Jisan-series, imperfectly drained and Yongji-series, moderately well drained). 1. Average grain yield of rice in no fertilizer plots and the highest yield plots for Yongji-series (31 experiments) were 319 and 507kg/10a respectively, and that of Jisan-series (15 experiments) were 396 and 567kg/10a respectively. The fertility difference between two series may have been a result of the cultivation history. Jisan-series is a mature soil which has a long cultivation history and Yongji-series is sub-mature soil 2. Soil chemical characteristics for Jisan-series are charaterized by 12.8meq/100g in CEC, 6.5meq/100g in exchangeable Ca, 3.9% in OM, and 64 ppm in available $P_2O_5$ For Yongji-series they were 10.4meq/100g in CEC, 4.7meq/100g in exchangeable Ca, 3.2% in OM and 103ppm in available $P_2O_5$. 3. Deep plowing and application of organic matter and lime are expected to be effective in increasing fertility level of soils of Yongji-series. The same will be effective in some soils of Jisan series where the fertility level is low. 4. Jisan-series shows high response to nitrogen, while Yongji series shows sharp decrease in rice yield at the high levels of nitrogen. Both series, however, showed high response to nitrogen only when the OM level was higher than 3%. 5. The optimum level of nitrogen was 8~9kg for Jisan-series, and 10~11kg/10a for Yongji-series. The yield increase per kg of applied nitrogen was 12kg for Jisan-series and 13kg for Yongji series. 6. The optimum level of phosphorus at the optimum level of nitrogen was 6kg/10a for Yongji-series and 3kg/10a for Jisan-series. The optimum level of phosphorus, however, was different depending upon the nitrogen level. It was assumed that Yongji-series required more fertilizer (available $P_2O_5$ was 110ppm) than Jisan-series (available $P_2O_5$ was 64ppm) because the availability of P was higher in Jisan-series than Yongji-series due to the severe reduction of Jisan-series. 7. The response of potassium was also depending upon the nitrogen level. In Yongji-series the potassium response at 8kg/10a nitrogen level decreased with increasing levels of potassium, but the higher level of introgen, potassium response was also higher. In Jisan-series potassium response was recognized at all nitrogen levels. The optimum level of potassium at the optimum level of nitrogen was 8kg/10a in both serieses. 8. The reasonable ratio of NPK fertilizer seems to be 1:0.6:0.6:for Yongji-series and 1:0.4:1 for Jisan-series as N:$P_2O_5$:K.