• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.125-130
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• 2010

The application of bioreactor culture techniques for plant micropropagation is regarded as one of the ways to reduce production cost by scaling-up and automation. In an attempt to optimize mass proliferation systems in Eucalyptus pellita, four types of bioreator systems including temporary immersion system with or without net were tested. Highest growth was achieved with 30-min flushes of medium at every 4-h intervals in TIN (temporary immersion with net) system. Results indicate over three-fold increase in shoot growth with the TIN system when compared with TIX (control: temporary immersion without net) system which is without net in bioreactor. Furthermore, plants produced from the TIN system increased total chlorophyll content, chlorophyll a/b and dry matter, giving higher yields of acclimatized plants. Our findings suggest that plantlet growth increases with appropriate exposure to media at correct intervals, as well as use of net for maintaining aerobic condition in the vessels. The TIN system thus has great potential for in vitro mass production of Eucalyptus clones commercially.

• Tuberculosis and Respiratory Diseases
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• v.74 no.4
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• pp.163-168
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• 2013

Background: In uncontrolled hemoptysis patient, bronchial arteriography and bronchial artery embolization (BAE) is a important procedure in diagnosis and treatment. The aim of this study is to assess the incidence of contrast-induced nephropathy and the risk factors of contrast-induced nephropathy (CIN) after bronchial arteriography and BAE. Methods: We retrospectively reviewed the medical records of the patients who underwent bronchial arteriography and BAE in two university hospitals from January 2003 to December 2011. CIN was defined as rise of serum creatinine more than 25% of baseline value or 0.5 mg/dL at between 48 hours and 96 hours after bronchial arteriography and BAE. We excluded patients who already had severe renal insufficiency (serum creatinine${\geq}4.0$) or had been receiving dialysis. Results: Of the total 100 screened patients, 88 patients met the enrollment criteria. CIN developed in 7 patients (8.0%). The mean duration between the exposure and development of CIN was $2.35{\pm}0.81$ days. By using multivariate analysis, serum albumin level was found to be significantly associated with the development of CIN (p=0.0219). Conclusion: These findings suggest that the incidence of CIN was higher than expected and patients with hypoalbuminemia should be monitored more carefully to prevent the development of CIN after bronchial arteriography and BAE.

• Journal of Embryo Transfer
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• v.10 no.2
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• pp.121-129
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• 1995

To examine the critical effect of oxygen concentration on embryonic development, in vitro fertilized embryos were cultured in media(TCM199 vs. SOF) supplemented sera(1O% FCS vs. 10% HS) with and without bovine oviduct epithelial cells under two gas atmosphere (5% $CO_2$ in air vs. 5% $CO_2$, 5% $O_2$, 90% $N_2$). Oocytes, obtained from abattoir ovaries, were matured in EGF containing TCM199 medium co-cultured with BOEC for 24 hours, followed by exposure to frozen-thawed, heparin4reated spermatozoa in TALP for 30 hours. And then early embryos(1~2 cell) were cultured in both TCM199 and SOF supplemented with 10% FCS or 10% RS under 5% $CO_2$ in air or 5% COi, 5% $O_2$, 90% $N_2$. Development to morulae and blastocysts was recorded on days 7, after the start of in vitro fertilization. The developmental rates of in vitro fertilized embryos to morulae and blastocysts cultured in SOF with BOEC under 5% $CO_2$, 5% $O_2$, 90% $N_2$(24.4%) were significantly(p<0.05) higher than cultured in SOF with BOEC under 5% $CO_2$ in air(14.1%) at seven days after in vitro fertilization. When early bovine embryos were cultured in TCM 199 and SOF under two different gas atmosphere, there were no significant differences in the developmental rates to morulae and blastocysts between supplements of 10% FCS and 10% HS. The rates of development to morulae and blastocysts were significantly(p<0.01) higher in TCM 199 with BOEC(24.7%) than TCM199 without BOEC(10.9%) under 5% $CO_2$ in air, otherwise SOF without BOEC(36.4%) were significantly (p<0.05) higher than in SOF with BOEC (24.4%) under 5% $CO_2$, 5% $O_2$, 90% $N_2$. In summary, these experiments have proved that the culture system in SOF supplemented 10% ES is effective on in vitro development of early bovine embryos under 5% $CO_2$, 5% $O_2$, 90% $N_2$. In addition, it is effective to development of bovine embryos that TCM 199 should be co-cultured with BOEC and SOF should be cultured without somatic cells under two different gas atmosphere.

• Journal of Science and Technology Studies
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• v.18 no.1
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• pp.129-175
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• 2018

This paper examines asbestos activism in South Korea by focusing on the politics of knowledge between the asbestos activist group and regulatory agency on the risk of asbestos exposure. Asbestos activism has contributed to establishing asbestos pollution an important safety and public health agenda in South Korea. Asbestos pollution investigation is key to core argument of the activism that asbestos pollution is pervasive especially in urban environment and a serious environmental health problem with its worst consequences has not yet seen. A distinctive characteristic of such asbestos investigation is the use of "settled dust analysis," non-standard, non-legislated analysis method. In this paper, literary technologies used in asbestos investigation report written by activists and controversies over asbestos pollution measurement in Samsung's head office building. Asbestos activists successfully concentrated media's attention on their argument and mobilize resources needed to make policy decisions, by using settled dust analysis data. Regulatory agency and expert group, however, neither saw settled dust analysis nor activists argument persuasive enough to make policy changes, base on their evaluation on the use of standards and evidentiary context for analyzing measured data. While its explanatory power is partially acquired, through the dispute between asbestos activists and regulatory agencies unspoken assumptions of regulatory science was revealed and became the matter of social debate. Settled dust analysis captures the characteristic of asbestos analysis which combined social movement and science to challenge the regulatory agency and expert group.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.191-195
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• 2000

This study was undertaken to estimate the exposed dose of the medical personnel during the intracoronary radiotherapy procedure as a part of ongoing SPARE (Seoul National University Hospital Post-Angioplasty Rhenium) trial. Data of thirty-four patients among forty-two irradiated patients participating in this trial due to coronary artery stenosis were retrospectively analyzed. Intracoronary radiotherapy was delivered to the patient immediately after angioplasty ballooning. Prescribed dose was 17 Gy to media of the diseased artery and was delivered with $^{188}Re$ filled balloon catheter. Dosimetry was carried out with GM counter at eight different points. Ten centimeter and forty centimeter from the patient's heart were selected to represent maximum and whole-body exposed dose of the operator, respectively. Median delivered dose was 111.6 mCi with average treatment time of 576 seconds. Average exposed dose rate at 10 cm and 40 cm from the patient's heart were 0.43 mSv/hr and 0.30 mSv/hr, respectively. Average exposed doses per treatment were 0.07 mSv and 0.05 mSv for 10 cm and 40 cm from the patient's heart, respectively. Exposed doses measured are much lower than recommended limit of 50 mSv for radiation workers or 1 mSv for general population in ICRP-60. This study proves that current method of intracoronary radiotherapy incorporated in this trial is very safe regarding radiation protection.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.821-838
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• 1999

On the basis of the evidences that electrical stimulation could enhance proliferation and differentiation of bone cells and promote healing and regeneration of bone, this study was performed to investigate the effects of electrical stimulation on human periodontal ligament cells and gingival fibroblasts in vitro, which also have important roles in regeneration of periodontium, and to evaluate the potential of clinical application of electrical stimulation. Human periodontal ligament cells and gingival fibroblasts were primarily cultured from the root surface of extracted premolar and the adjacent gingiva without periodontal diseases. In control group, the cells ($5{\times}10^4$ cells/ml)were incubated only in Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In test groups, electrical stimulation was given at the current intensity of $0.25{\mu]A$(test group 1), $1.0{\mu}A$(test group 2), and $2.5{\mu}A$(test group 3) for 12 hours to the same culture media with the control group. After 12 hour exposure of electrical stimulation, the cells were incubated for 2 and a half days(60 hours), and then each group of cells was analyzed for cell proliferation, protein level, and activity of alkaline phosphatase. The results were as follows ; 1. The Rate of cell proliferation of every test group increased significantly in both periodontal ligament cells and gingival fibroblasts, and in periodontal ligament cells, test group 3 showed significantly increased proliferation compared to the other test groups(p<0.05). 2. In the protein levels, neither periodontal ligament cell nor gingival fibroblast showed statistically significant differences between control and test groups. 3. The activity of alkaline phosphatase in periodontal ligament cells increased significantly in all test groups(p<0.05), but there were no significant differences between 3 test groups. In gingival fibroblasts, the activity of alkaline phosphatase increased significantly only in test group 3(p<0.05). From the above results, it is concluded that electrical stimulation may have beneficial effects on the regeneration of destructed periodontal tissue in regard of the stimulation of periodontal ligament cells and gingival fibroblasts as well as electrically stimulated bone formation that has been known, and that electrical stimulation may have the potential of clinical application.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• Journal of Life Science
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• v.24 no.12
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• pp.1330-1338
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• 2014

In Mycobacterium tuberculosis H37Rv 16 adenylyl cyclase (AC) genes have been identified, while 10 AC genes have been found in non-pathogenic Mycobacterium smegmatis. Expression of 6 AC genes (MSMEG_0218, MSMEG_3243, MSMEG_3780, MSMEG_4279, MSMEG_4477, and MSMEG_6154) among 10 AC genes in M. smegmatis was increased when M. smegmatis was subjected to hypoxic growth conditions. On the other hand, only MSMEG_3780 and MSMEG_4279 were slightly induced in the presence of NO. The cAMP levels in cells and culture media were 450- and 9.8-fold increased, respectively, when M. smegmatis was grown under hypoxic conditions relative to those grown aerobically. Intracellular levels of cAMP were increased 5.8-fold on the exposure to NO. The DevSR two-component system is known to be involved in the induction of many genes whose expression is induced under hypoxic conditions and in the presence of NO. Expression of 6 hypoxically induced AC genes was observed to be induced in a devR deletion mutant grown under hypoxic conditions, indicating that the induction of the 6 AC genes under hypoxic conditions is independent of the DevSR two-component system. In order to identify a trans-acting regulatory element that is pertinent in the hypoxic induction of MSMEG_3780, ligand-fishing analysis was performed using the upstream DNA of MSMEG_3780 and MSMEG_5136 protein was identified.

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.187-195
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• 1995

The present study carried out to determine the developmental capacity of bovine oocytes matured in epidermal growth factor(EGF)-containing medium, the developmental competence of bovine embryos using synthetic oviduct fluid(SOF) and the effect of glucose on the development of bovine embryos. In experiment 1, oocytes, obtained from abattoir ovaries, were matured in EGF-containing medium for 24 hours, followed by exposure to Korean native cattle spermatozoa for 18 hours and cultured by utilizing co-culture system with bovine oviduct epithelial cells(BOEC) in TCM199. In experiment 2, early bovine embryos were cultured in SOF with or without BOEC and compared with those in TCM199 with BOEC. In experiment 3, bovine embryos were cultured in the presence or absence of glucose. Seven and ten days after in vitro fertilization, developmental competence of embryos were evaluated. The rate of cleavage was significantly(P<0.05) higher in EGF-containing maturation medium(70.0%) than in control(57.7%). The rates of development to morulae and blastocysts were 30.6% and 23.3% there was no significant difference between them. The rates of in vitro fertilized embryos to morulae and blastocysts cultured in SOF with BOEC(30.4%) and in TCM199 with BOEC(38.0%) were significantly(P<0.01) higher than cultured in SOF without BOEC(13.4%) at seven days after in vitro fertilization. The rates of embryos to blastocysts cultured in SOF with BOEC(29.4%) and in TCM199 with BOEC(35.9%) were significantly(P<0.05) higher than cultured in SOF without BOEC(13.4%) at ten days after in vitro fertilization. The rates of early embryos to morulae and blastocysts cultured in the presence or absence of glucose were 12.2% and 17.5% each other, there was no significant difference between them. The results show that bovine oocytes matured in the presence of EGF can cleave better, SOF with BOEC can replace serum containing complex media, TCM199 with BOEC in bovine embryo culture and glucose have little effect on the culture of early bovine embryos.