• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.15-21
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• 2012

Purpose: Image Guided Radiation Therapy (IGRT) has been carried out using On-Board Imager system (OBI) in Asan Medical Center. For this reason, This study was to analyze and evaluate the impact on Cone-Beam CT according to variation of material and respiration. Materials and Methods: This study was to acquire and analyze Cone-Beam CT three times for two material: Cylider acryl (lung equvalent material, diameter 3 cm), Fiducial Marker (using clinic) under Motion Phantom able to adjust respiration pattern randomly was varying period, amplitude and baseline vis-a-vis reference respiration pattern. Results: First, According to a kind of material, when being showed 100% in the acryl and 120% in the Fiducial Marker under the condition of same movement of the motion phantom. Second, According to the respiratory alteration, when being showed 1.13 in the baseline shift 1.8 mm and 1.27 in the baseline shift 3.3 mm for acryl. when being showed 1.01 in 1 sec of period and 1.045 in 2.5 sec of period for acryl. When being showed 0.86 in 0.7 times the standard of amplitude and 1.43 in 1.7 times the standard of amplitude for acryl. when being showed 1.18 in the baseline shift 1.8 mm and 1.34 in the baseline shift 3.3 mm for Fiducial Marker. when being showed 1.0 in 1 sec of period and 1.0 in 2.5 sec of period for Fiducial Marker. When being showed 0.99 in 0.7 times the standard of amplitude and 1.66 in 1.7 times the standard of amplitude for Fiducial Marker. Conclusion: The effect of image size of CBCT was 20% in the case of Fiducial marker. The impact of changes in breathing pattern was minimum 13% - maximum 43% for Arcyl, min. 18% - max. 66% for Fiducial marker. This difference makes serious uncertainty. So, Must be stabilized breathing of patient before acquiring CBCT. also must be monitored breathing of patient in the middle of acquire. If you observe considerable change of breathing when acquiring CBCT. After Image Guided, must be need to check treatment site using fluoroscopy. If a change is too big, re-acquiring CBCT.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.185-195
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• 2012

Due to the high reduction and sorption capacity as well as the large specific surface area, nanosized mackinawite (FeS) is useful in reductively transforming chlorinated organic pollutants and sequestering toxic metals and metalloids. Due to the dynamic nature in its colloid stability, however, nanosized FeS may be washed out with the groundwater flow or result in aquifer clogging via particle aggregation. Thus, these nanoparticles should be modified such as to be built into permeable reactive barriers. This study employed coating methods in efforts to facilitate the installation of permeable reactive barriers of nanosized mackinawite. In applying the methods, nanosized mackinawite was coated on non-treated silica sand (NTS) and chemically treated silica sand (CTS). For both silica sands, the maximum coating of mackinawite occurred around pH 5.4, the condition of which was governed by (1) the solubility of mackinawite and (2) the surface charge of both silica and mackinawite. Under this pH condition, the maximum coating by NTS and CTS were found to be 0.101 mmol FeS/g and 0.043 mmol FeS/g respectively, with such elevated coatings by NTS likely linked with impurities (e.g., iron oxides) on its surface. Arsenite sorption experiments were performed under anoxic conditions using uncoated silica sands and those coated with mackinawite at the optimal pH to compare their reactivity. At pH 7, the relative sorption efficiency between uncoated NTS and coated NTS changed with the initial concentration of arsenite. At the lower initial concentration, uncoated NTS showed the higher sorption efficiency, whereas at the higher concentration, coated NTS exhibited the higher sorption efficiency. This could be attributed to different sorption mechanisms as a function of arsenite concentration: the surface complexation of arsenite with the iron oxide impurity on silica sand at the low concentration and the precipitation as arsenic sulfides by reaction with mackinawite coating at the high concentration. Compared to coated NTS, coated CTS showed the lower arsenite removal at pH 7 due to its relatively lower mackinawite coating. Taken together, our results indicate that NTS is a more effective material than CTS for the coating of nanosized mackinawite.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.125-135
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• 2009

Statement of problem: Loosening or fracture of the abutment screw is one of the common problems related to the dental implant. Generally, in order to make the screw joint stable, the preload generated by tightening torque needs to be increased within the elastic limit of the screw. However, additional tensile forces can produce the plastic deformation of abutment screw when functional loads are superimposed on preload stresses, and they can elicit loosening or fracture of the abutment screw. Therefore, it is necessary to find the optimum tightening torque that maximizes a fatigue life and simultaneously offer a reasonable degree of protection against loosening. Purpose: The purpose of this study was to present the influence of tightening torque on the implant-abutment screw joint stability with the 3 dimensional finite element analysis. Material and methods: In this study, the finite element model of the implant system with external butt joint connection was designed and verified by comparison with additional theoretical and experimental results. Four different amount of tightening torques(10, 20, 30 and 40 Ncm) and the external loading(250 N, $30^{\circ}$) were applied to the model, and the equivalent stress distributions and the gap distances were calculated according to each tightening torque and the result was analyzed. Results: Within the limitation of this study, the following results were drawn; 1) There was the proportional relation between the tightening torque and the preload. 2) In case of applying only the tightening torque, the maximum stress was found at the screw neck. 3) The maximum stress was also shown at the screw neck under the external loading condition. However in case of applying 10 Ncm tightening torque, it was found at the undersurface of the screw head. 4) The joint opening was observed under the external loading in case of applying 10 Ncm and 20 Ncm of tightening torque. 5) When the tightening torque was applied at 40 Ncm, under the external loading the maximum stress exceeded the allowable stress value of the titanium alloy. Conclusion: Implant abutment screw must have a proper tightening torque that will be able to maintain joint stability of fixture and abutment.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.4
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• pp.506-521
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• 2007

Statement of problem: The cumulative success rate of wide implant is still controversial. Some previous reports have shown high success rate, and some other reports shown high failure rate. Purpose: The aim of this study was to analyze, and compare the biomechanics in wide implant system embeded in different width of crestal bone under different occlusal forces by finite element approach. Material and methods: Three-dimensional finite element models were created based on tracing of CT image of second premolar section of mandible with one implant embedded. One standard model (6mm-crestal bone width, 4.0mm implant diameter central position) was created. Varied crestal dimension(4, 6, 8 mm), different diameter of implants(3.3, 4.0, 5.5, 6.0mm), and buccal position implant models were generated. A 100-N vertical(L1) and 30 degree oblique load from lingual(L2) and buccal(L3) direction were applied to the occlusal surface of the crown. The analysis was performed for each load by means of the ANSYS V.9.0 program. Conclusion: 1. In all cases, maximum equivalent stress that applied $30^{\circ}$ oblique load around the alveolar bone crest was larger than that of the vertical load. Especially the equivalent stress that loaded obliquely in buccal side was larger. 2. In study of implant fixture diameter, stress around alveolar bone was decreased with the increase of implant diameter. In the vertical load, as the diameter of implant increased the equivalent stress decreased, but equivalent stress increased in case of the wide implant that have a little cortical bone in the buccal side. In the lateral oblique loading condition, the diameter of implant increased the equivalent stress decreased, but in the buccal oblique load, there was not significant difference between the 5.5mm and 6.0mm as the wide diameter implant. 3. In study of alveolar bone width, equivalent stress was decreased with the increase of alveolar bone width. In the vertical and oblique loading condition, the width of alveolar bone increased 6.0mm the equivalent stress decreased. But in the oblique loading condition, there was not a difference equivalent stress at more than 6.0mm of alveolar bone width. 4. In study of insertion position of implant fixture, even though the insertion position of implant fixture move there was not a difference equivalent stress, but in the case of little cortical bone in the buccal side, value of the equivalent stress was most unfavorable. 5. In all cases, it showed high stress around the top of fixture that contact cortical bone, but there was not a portion on the bottom of fixture that concentrate highly stress and play the role of stress dispersion. These results demonstrated that obtaining the more contact from the bucco-lingual cortical bone by installing wide diameter implant plays an important role in biomechanics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.367-372
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• 2002

In order to utilize safflower seed effectively as a food material, it was processed at the conditions including roasting temperature/time of 170$\^{C}$/10 min to 210$\^{C}$/30 min, ethanol concentration of 0 to 100% (V/V) and enzyme hydrolysis with $\alpha$-amylase, $\beta$-amylase, amyloglucosidase and cellulase. Safflower seed extracts had the highest soluble solid content at the condition of 60% ethanol concentration, roasting at 190$\^{C}$ for 20 min and hydrolysis with amyloglucosidase. Total phenolic compounds increased with the ethanol concentration, showing the highest at the condition of 80% ethanol, roasting at 170$\^{C}$ for 30 min and hydrolysis with amyloglucosidase. High level total flavonoid was observed at the condition of 80% ethanol, roasting at 210$\^{C}$ for 30 min and hydrolysis with amyloglucosidase. Safflower seed had sucrose as major free sugar as well as xylose and arabinose as minor free sugars. Organic acids in safflower seed included oxalic, citric, magic and fumaric acid. Serotonin I (N-[2-(5-hydroxy-1H-indo-1-3-yl)ethyl]ftrulamide) and serotonin II (N-[2-(5-hydroxy-1H-indol-3yl)ethyl]-p-coumaramide) as antioxidant compounds increased with ethanol concentration, showing the highest revel at 60% ethanol. Acacetin content increased with temperature and roasting time, with a maximum of 69.47 mg% at 210$\^{C}$ for 30 min.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.4
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• pp.189-195
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• 2022

Purpose: For orthodontic bracket bonding, light curing resin cement is widely used because the process is convenient, and it can be polymerized at the desired time. This study compared the difference of bonding strength of orthodontic resin cement according to storage condition. Materials and Methods: After acid etching the bovine enamel surface with 37% phosphoric acid, 15 orthodontic brackets for mandible incisors were bonded with Ortho Connect and Orthomite LC according to following three conditions; 1) Immediate after 4℃ refrigeration for 3 months (IR), 2) One day room temperature after 4℃ refrigeration for 3 months (OR), 3) Room temperature for 3 months (RT). The shear bond strength was measured with a universal material tester and failure pattern of the specimen was observed. Two-way ANOVA and One-way ANOVA were used at the 95% significance level. Results: Ortho Connect that was applied immediately after refrigeration showed the maximum shear bond strength. Orthomite that was applied immediately after refrigeration showed the lowest shear bond strength, and the group stored at room temperature for three months showed the highest shear bond strength, and the difference between the two groups was significant. Conclusion: Ortho Connect can be used without worrying about bond strength even if it is used immediately after refrigeration, but Orthomite should be kept at room temperature sufficiently after refrigeration.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2180-2189
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• 2017

Psychrophilic phytases suitable for aquaculture are rare. In this study, a phytase of the histidine acid phosphatase (HAP) family was identified in Morchella importuna, a psychrophilic mushroom. The phytase showed 38% identity with Aspergillus niger PhyB, which was the closest hit. The M. importuna phytase was overexpressed in Pichia pastoris, purified, and characterized. The phytase had an optimum temperature at $25^{\circ}C$, which is the lowest among all the known phytases to our best knowledge. The optimum pH (6.5) is higher than most of the known HAP phytases, which is fit for the weak acidic condition in fish gut. At the optimum pH and temperature, MiPhyA showed the maximum activity level ($2,384.6{\pm}90.4{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$, suggesting that the enzyme possesses a higher activity level over many known phytases at low temperatures. The phytate-degrading efficacy was tested on three common feed materials (soybean meal/rapeseed meal/corn meal) and was compared with the well-known phytases of Escherichia coli and A. niger. When using the same amount of activity units, MiPhyA could yield at least $3{\times}$ more inorganic phosphate than the two reference phytases. When using the same weight of protein, MiPhyA could yield at least $5{\times}$ more inorganic phosphate than the other two. Since it could degrade phytate in feed materials efficiently under low temperature and weak acidic conditions, which are common for aquacultural application, MiPhyA might be a promising candidate as a feed additive enzyme.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1052-1060
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• 1999

Tire and raw material of tire, i.e., SBR were degraded using pyrolysis process. The yield of pyrolytic oil was increased and that of gas was decreased with increase of operating temperature in pyrolysis. And the yield of pyrolytic oil was increased and that of gas and char was decreased with increase of heating rate. The maximum oil yields of SBR and tire were 86% and 55% each at $700^{\circ}C$ with a heating rate of $20^{\circ}C/min$. The number average molecular weight ranges of SBR and tire were 740~2486, 740~1719, and the calorific value of SBR and tire was 39~40 kJ/g. The oil components were consisted of mostly 50 aromatic compounds. The particle size was decreased and the surface area was increased with increase of operating temperature, and the BET surface area was $47{\sim}63m^2/g$. The optimum condition of pyrolysis was the temperature of $700^{\circ}C$ with heating rate of $20^{\circ}C$, and the reactor was continuously purged with inert gas to sweep the evolved gases from the reaction zone.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.238-243
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• 2001

Mass reduction and physicochemical properties of the produced compost were investigated during composting domestic food wastes without additive. A small composter used in this study had the height of 15 cm from the center of bottom half circle (diameter 24 cm) up to under the lid, the side length of 50 cm and the horizontal lid angle of $50^{\circ}$ and was operated at the heating unit temperature of $85^{\circ}$. It was mixed by the rotating arm for two minutes in every half hour while supplied with air flow at 3 L/min for 10 minutes in every half hour. This condition was found in a preliminary experiment as optimal for keeping the water content of composting material in the optimal range without adding any bulking materials. The domestic food wastes were added into the composter at the rate of 1 kg/day without additives during composting. The results were as follows; during the composting process, water content maintained in the range of $51.0{\sim}53.5%$. Hemicellulose and lignin contents did not show any tendency, but cellulose content decreased. During the composting process, $NH_3-N$ and $NO_2-N$ were not detected due to nitrification. The contents of inorganic compounds did not increase during the composting process. They were in the range of $1.32{\sim}1.71%\;P_2O_5$, $1.29{\sim}1.48%\;CaO$, $0.41{\sim}0.49%\;MgO$, and $0.38{\sim}0.74%\;K_2O$. For 20 days, weight reduction rate was 67.5% in wet basis, and decomposition rate was 48% in dry basis. Concentration of heavy metals (Cu, Cr, Cd, Pb, Zn, Hg, As) was less than the limiting value of the compost. Maturity of the produced compost was 3 grade through reaching maximum temperature of $46{\sim}48^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.83-88
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• 1974

The water pollution by waste water is one of the important issue and the short of animal feed is too, in Korea. So, this experiment is accomplished to treat alcohol distillers' waste by micro-organisms and planning to produce yeasts, which can be used as animal feed, pharmacy and condiments. 1. The raw material, alcohol distillers' waste, of this experiment consists of insoluble solids (residue) and filterate (supernatant). The residue contains 33.08％ of crude protein, 19.96％ of total sugar. and 2.06％ of ash, respectively. On the other hand the flterate through the Toyo filter paper No. 5C, contains 2.48％ of crude protein, 1.54％ of reducing sugar, and 0.43％ of ash, respectively. 2. Optimum pH of the basal medium for the growth of Saccharomyces cerevisiae YF-1 is 4.0. Optimum culture condition of this is as follows : when 0.43g of urea, 0.43g of potassium phosphate monobasic, and 0.21g of magnesium sulfate are added to the 100m1 of basal medium. Optimum temperature and optimum incubation time are 30$^{\circ}C$ and 24-28 hrs. 3. Under these conditions, the maximum yield of dry yeast is 1.38％ to the medium. 4. The composition of dry yeast, produced under these conditions, is as follows: crude protein, 56.96％, lipid, 1.30％. total sugar, 6.53％, and ash 9.62％.