• Applied Biological Chemistry
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• v.49 no.1
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• pp.25-29
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• 2006

This study was carried out to isolate the possible anti-tumor promoters from the citrus peel (Citrus natsudaidai Hayata). We fractionated the cold-pressed oil of citrus peel by column chromatography, HPLC and TLC. The analysis on column chromate-graphy yielded seven peaks $(F-I{\sim}F-VII)$, all of which showed single spot on TLC analysis ($R_f$ for $F-I{\sim}VIII$; 0.31, 0.13, 0.13, 0.78, 0.79, 0.69 and 0.84). Among the seven fractions, three fractions (F-I, -II and F-IV) were re-analyzed on HPLC, also showing single peak except for one fraction (F-IV) which was divided two peaks. The retention times $(R_f)$ of F-I and F-II was 3 min. and 2.5 min., respectively, but these of two peaks from F-IV were 2 min. and 4.5 min., respectively. Since the area of the latter peak (4.5 min.) was very smaller than that of the former one (2 min.), it is considered that the latter one did not appear on TLC analysis. The inhibitory effect on tumor promoter 12-O-tetradecanoylphorbol-13-acetate(TPA)-induced Epstein-Barr virus activation in Raji cells was tested for the seven fraction obtained. It decreased in order of F-VI (82.3+1.3%) > F-I (80.4+1.6%) > F-II (77.2+0.9%) > F-III (75.0+1.2%) > F-IV (74.1=1.0%) > F-V (71.0+1.1%) > F-VII (70.2+1.2%). These results imply that some constiuents contained in citrus peels have the inhibitory activity of TPA-induced tumor promotion.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.589-598
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• 1995

Filtering rates of Crassostrea gigas were experimentally investigated with reference to effects of water temperature and size. Absorptiometric determinations of filtering rates with oysters being fed diatom Chaetoceros calcirtans were carried out in a closed system. Optical density of 675nm in path length 100mm cell used as the indication of food particles absorption was appeared directly In proportion with the concentration of diatom pigment $chlorophyll-\alpha$. In the closed system where $C_0$ is $OD_{675}$ at initial time 0, $C_t$, at time t, and Z is the decreasing coefficient of OD as meaning of instantaneous removal speed, then $C_t=C_0{\cdot} e^{-2t}$, $Z=In(C_t/C_0)/t$. On the assumption that the filtering rate is constant, then removal rate per unit time (d) is $d=-e^{-z}$. If t is used to time unit of hour (hr), the filtering rate (FR) in I/hr is given by $FR=V{\cdot}d=V(1-e^{-z})$, where V is the water volume (I) of the experimental vessel. Filtering rate increased as exponential function with increasing temperature while not over critical limit. The critical temperature for filtering rate was assumed to be between $28^{\circ}C$ and $29^{\circ}C$. And the weight exponent for filtering rate is 0.223. The model formula derived from the results as FR, $Ihr^{-1}$ = $Exp(0.208{\cdot}T-4.324){\cdot} (DW)^{0.223}$ (T<29 $^{\circ}C)$ where T is water temperature $(^{\circ}C

• Journal of the Korean Magnetics Society
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• v.12 no.3
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• pp.99-102
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• 2002

We fabricated TMR devices which have doubly oxidized tunnel barrier using plasma oxidation method to form homogeneously oxidized AlO tunnel barrier. We sputtered 10 $\AA$-bottom Al layer and oxidized it with oxidation time of 10 sec. Subsequent sputtering of 13 $\AA$-Al was performed and the metallic layer was oxidized for 50, 80, and 120 sec., respectively. The electrical resistance changed from 500 Ω to 2000 Ω with increase of oxidation time, while variation of MR ratio was little spreading 27∼31 % which is larger than that of TMR device of ordinary single tunnel barrier. We calculated effective barrier height and width by measuring I-V curves, from which we found the barrier height was 1.3∼1.8 eV sufficient for tunnel barrier, and the barrier width (<15.0 $\AA$) was smaller than physical thickness. Our results may be caused by insufficient oxidation of Al precursor into A1$_2$O$_3$. However, doubly oxidized tunnel barriers were superior to conventional single tunnel barrier in uniformity and density. Our results imply that we were able to improve MR ratio and tune resistance by employing doubly oxidized tunnel barrier process.

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.380-392
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• 2002

The purpose of the present study is to evaluate the usage of microtremor in estimation of subsurface structure and ground response to strong ground motion. To accomplish the purpose, the current status of microtremor study are reviewed and microtremors recorded at several stations are analysed. First of all, the stability of microtremor is examined through the analysis of microtremors recorded for 80 seconds per hour during the time from 10 p.m. to 6 a.m. for eight hours at night time. It is found that the shape of microtremor spectra of low frequency below 10Hz is approximately invariable with time and the spectra contain informations about subsurface structure. The subsurface structures estimated from the predominant frequency determined from the recorded microtremors are compared with the known ones from geophysical surveys at several stations in Kyungju. The comparison of structures shows rough agreements at most stations. Horizontal to vertical spectral ratio(HVSR) technique for microtremor has been proposed as an indirect method to determine ground response to strong ground motion. The HVSR for microtremors recorded in Kyungju is calculated and compared with theoretical transfer function calculated from the known structures. The comparison shows rough coincidence of the peak frequency of spectra between them.

• Korean Journal of Food Science and Technology
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• v.47 no.2
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• pp.145-148
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• 2015

According to the Korea Food Additives Code, sodium metasilicate is permitted for use as a filtering agent for edible oils and fats. Sodium metasilicate is currently used as a food additives to increase the weight of shark fins. In this study, we developed an analytical method to quantify sodium metasilicate in food. Sodium metasilicate content was estimated by measuring the moisture content, pH and silicon content of shark fins. Silicon content was analyzed using inductively coupled plasma-optical emission spectrometry (ICP-OES) following microwave-assisted digestion with $HNO_3$ (65%) and $H_2O_2$ (30%). Shark fin total silicon content was $7.17{\pm}8.92mg/kg$, while the soluble silicon content was $2.34{\pm}3.80mg/kg$. After soaking raw shark fin in an aqueous solution of sodium metasilicate, fin weight, pH and silicon content were measured. These results would be used as the basic information for shark fins safety management.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.55-61
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• 2021

In this study, microbes were collected before and after disinfection using ANIOS(ANIOSURF Premium NPC) and compared the areas where the radiological technologist and the patient frequently contacted the chest X-ray. From September 1st to September 7th, 2020. in P Hospital in Deagu, 4 region were collected in a 10×10 size using a sterile cotton swab of the transport medium, and before and after disinfection results were obtained through the colorimetric method. As a result, n the X-ray tube handle Proteus mirabilis, Staphylococcus epidermidis, Bacillus spp., Candida spp., and in the Chin region Proteus mirabilis, Enterococcu faecium, Pseudomonas aeruginosa, NTM, and in the Chest region Proteus mirabilis, Enterococcu faecium, Pseudomonas aeruginosa, and in the Palm region NTM, Candida spp. were detected, and 103 CFU(Colony Forming Unit) or more were measured. After disinfection, only X-ray tube handle was detect Bacillus spp. and more than 102 CFU was measured. Microorganisms found prior to disinfection can cause opportunistic infections, Experimental results showed that Aniosulf(0.25%) is more economical and disinfectant than ethanol(70-90%) and isopropyl alcohol(70-90%). However, further research is needed on the detection of Bacillus spp. resultingly this research is useful basic data of infection control in Radiography room and prevention secondary infections.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1344-1350
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• 2003

This study was performed to investigate the antioxidative effect as the inhibition of malondialdehyde (MDA) and bovine serum albumin (BSA) conjugation reaction, inhibition of lipid peroxidation and the scavenging effect on 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical, and antimutagenic capacities as the Ames test in 7 common vegetables taken by Korean for suggestion of prevention and dietetic treatment of chronic diseases and development of antioxidative and antimutagenic functional food. The water fractions of perilla leaves and sedum were most effective in the inhibition of MDA and BSA conjugation reaction showing 62.5% of inhibition rate among 7 vegetables. The inhibition rates of ethanol fractions of sedum and wild water dropwort on the lipid peroxidation were 67.1% and 61.5%, respectively. The ethanol fractions of crown daisy and wild water dropwort showed the most effective results among 7 vegetables in the DPPH radical scavenging capacities showing inhibition rate of 78.8% and 73.6%, respectively. The indirect and direct antimutagenic effects of ethanol extract of 7 vegetables were examined by Ames test using Salmonella typimurium TA98 and TA100. Inhibitory effects of wild water dropwort was superior to the other vegetables on the Ames test. These results suggest that common 7 vegetables taken by Korean are believed to be a possible antioxidative and antimutagenic capacities, although the results were different, more or less, according to the assay method and vegetables used.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.175-188
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• 2008

This study was performed to describe the influence of water temperature and salinity on the filtration rate of the hard clam, Meretrix petechialis. The filtration rates of hard clams showed significant differences depending on both water temperature and age group (two-way ANOVA, p < 0.001). The filtration rate of all the hard clams, aged from 1 to 4 years, was generally reduced in low temperature range ( $5-15^{\circ}C$). As the water temperature increased, the filtration rate increased exponentially. The filtration rate was relatively high in $20-30^{\circ}C$ water temperature range, but rapidly decreased again at around $35^{\circ}C$. Variations in the data for filtration rates of hard clams, relative to age and changing water temperature, were used to determine the temperature coefficient $Q_{10}$ in each water temperature range. In $5-15^{\circ}C$ temperature range, every age group showed the highest $Q_{10}$ figure. It was found that on the whole, the higher the water temperature was, the lower the number of $Q_{10}$ was. Regardless of age, the number of $Q_{10}$ was higher in the lower water temperature range. In $25-35^{\circ}C$ temperature range, the number of $Q_{10}$ was less than 1.00 in all age groups, implying that this is the range in which the filtration rate decreased. Variations in the filtration rate also showed very clear differences (two-way ANOVA, p < 0.001) according to changing salinity and age. All the age groups, from 1 to 4 year olds, showed low filtration rates at both low salinity (10-15 psu) and high salinity (40 psu). The highest filtration rate was recorded at 30 psu, and relatively high filtration rates were found around 30 psu. However, the Student-Newman-Keuls post hoc multiple comparison test found that the hard clams in the 1-year group showed high filtration rates in a relatively narrower salinity range compared to those in the 2, 3, and 4 year groups. In other words, hard clams in the 2, 3, and 4 year groups showed high filtration rates at higher levels of salinity.

• Journal of Korea Water Resources Association
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• v.56 no.4
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• pp.235-243
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• 2023

Due to the revision of the River Act and the enactment of the Act on the Investigation, Planning, and Management of Water Resources, a regular bed change survey has become mandatory and a system is being prepared such that local governments can manage water resources in a planned manner. Since the topography of a bed cannot be measured directly, it is indirectly measured via contact-type depth measurements such as level survey or using an echo sounder, which features a low spatial resolution and does not allow continuous surveying owing to constraints in data acquisition. Therefore, a depth measurement method using remote sensing-LiDAR or hyperspectral imaging-has recently been developed, which allows a wider area survey than the contact-type method as it acquires hyperspectral images from a lightweight hyperspectral sensor mounted on a frequently operating drone and by applying the optimal bandwidth ratio search algorithm to estimate the depth. In the existing hyperspectral remote sensing technique, specific physical quantities are analyzed after matching the hyperspectral image acquired by the drone's path to the image of a surface unit. Previous studies focus primarily on the application of this technology to measure the bathymetry of sandy rivers, whereas bed materials are rarely evaluated. In this study, the existing hyperspectral image-based water depth estimation technique is applied to rivers with vegetation, whereas spatio-temporal hyperspectral imaging and cross-sectional hyperspectral imaging are performed for two cases in the same area before and after vegetation is removed. The result shows that the water depth estimation in the absence of vegetation is more accurate, and in the presence of vegetation, the water depth is estimated by recognizing the height of vegetation as the bottom. In addition, highly accurate water depth estimation is achieved not only in conventional cross-sectional hyperspectral imaging, but also in spatio-temporal hyperspectral imaging. As such, the possibility of monitoring bed fluctuations (water depth fluctuation) using spatio-temporal hyperspectral imaging is confirmed.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.147-154
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• 2002

Purpose : Gingko biloba extract (GBE), a natural product extracted from Gingko leaves, is known to increase the radiosensitivity of tumors. This radiosensitization probably arises from the increase in the peripheral blood flow by decreasing the blood viscosity and relaxing the vasospasm. The influence of a GBE on the metabolic status in fibrosarcoma II (FSall) of a C3H mouse was investigated using $^{31}P$ magnetic resonance spectroscopy (MRS). Materials and Methods : Eighteen C3H mice with fibrosarcoma II $(from\;100\;mm^3\;to\;130\;mm^3)$ were prepared for this experiment. The mice were divided into 2 groups; one (9 mice) without a priming dose, and the other (9 mice) with a priming dose of GBE. The GBE priming dose (100 mg/kg) was administered by an intraperitoneal (i.p.) injection 24 hours prior to the measurement. First $^{31}P$ MRS spectra were measured in the mice from each group as a baseline and test dose of GBE (100 mg/kg) was then administered to each group. One hour later, the $^{31}P$ MRS spectra were measured again to evaluate the change in the energy metabolic status. Results : In the group without the priming dose, the mean pH, PCr/Pi, PME/ATP, Pi/ATP, PCr/(Pi+PME) values 1 hour after the test dose were not changed significantly compared to the values at the baseline. However, in the group with the priming dose, the mean PCr/Pi, Pi/ATP, PCr/(Pi+PME) values 1 hour after the test dose changed from the baseline values of 0.49, 0.77, 0.17 to 0.74, 0.57, 0.28 respectively. According to the paired t-test, the differences were statistically significant. Conclusion : The above findings suggest that the metabolic status is significantly improved after administering GBE if the priming dose is given 24 hours earlier. This shows that the radiosensitizing effect of GBE is based on the increase of tumor blood flow and the improvement in the metabolic status.