• Composites Research
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• v.30 no.3
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• pp.169-174
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• 2017

Demand of glass fiber reinforced composites (GFRC) increased with developing aircraft and defense industries using resin transfer molding (RTM) process to produce complex product. In this research, wetting, interfacial, and mechanical properties were evaluated with different Cross-linking Density by Molecular Weight of Hardener. Epoxy resin as matrices was used bisphenol-A type and amine-type hardeners with different molecular weight. Specimens were manufactured via RTM and wetting property of resin and glass fiber (GF) mat was evaluated to viscosity of epoxy and injection time of epoxy matrix. Mechanical property of GFRC was determined via flexural strength whereas interfacial properties were determined by interlaminar shear strength (ILSS) and interfacial shear strength (IFSS). The difference in mechanical property depends upon the fiber weight fraction (wt %) of GFRC by RTM as well as the different Molecular Weight of Hardener.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.415-417
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• 2002

Images of microcalcification specks showed large variation in conventional radiographs of phantoms which are approved for mammography image quality standard by the American College of Radiology (ACR). This kind of variation is not appropriate for image quality standards because the number of specks are visually counted in images and that number is important in image quality evaluation. Our study using synchrotron radiation (SR) imaging revealed the overlapping of micro-sized air bubble(s) to some specks, and also the structural deformation or crackings. Eight phantoms approved by ACR from two different makers and an air-bubble phantom were examined. SR imaging was performed at a synchrotron radiation facility, SPring-8, in Japan. The image-detector was a fluorescent-screen optical-lens coupling system using a CCD camera with a spatial resolution of 6 $\square$m. Objects when imaged with longer sample-to-detector distance show edge enhancement due to a difference in refraction indices, that is refraction enhancement. Refraction-enhanced SR images revealed that some of specks carried foreign objects, which were proven to be air. In phantoms provided by one maker, attaching/overlapping airs were observed for 62 out of 150 specks (41%) , with a higher incidence for the smallest specks. A speck becomes hardly visible in a conventional radiograph when air(s) overlaps the majority part of a speck, though depending on the size of the air-inclusion and on its configuration. Those airs might have been adsorbed on a speck surface before being embedded and then introduced into the matrix together with specks. Our study using SR imaging has clearly shown the nature of defects in some mammography phantoms which seriously degrade the quality as an image standard.

• Journal of dental hygiene science
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• v.5 no.3
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• pp.97-103
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• 2005

Irritation fibroma (IF) is the most common tumor-like oral lesion that is evolved by proliferation of collagen in response to chronic irritation. Oral leukoplakia (OL) is considered as precancerous lesion characterized by proliferation of epithelial cells due to chronic irritation, smoking and drinking. TGF-${\beta}1$ and EGFR are important factors that play an essential role in extracellular matrix remodeling during normal wound healing process. The epithelial reaction by chronic irritation may be connected with pathogenesis of IF and OL. In the present study, we examined the expression of TGF-${\beta}1$ and EGFR in the IF and OL using immunohistochemistry. We used 88 cases of IF, 44 cases of OL and 9 cases of normal oral mucosa as normal control. TGF-${\beta}1$ was decreased in the epithelium of IF and OL. As for EGFR, the epithelial cells revealed the increased positive expression in IF and OL. In case of OL, the Spearman correlation coefficient of TGF-${\beta}1$ and EGFR was -0.10 (p< 0.05), which showed weak correlation. In the fibrous tissue, TGF-${\beta}1$ was increased only in IF. The expression difference of TGF-${\beta}1$ and EGFR may be involved in the pathogenesis of IF and OL.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.11
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• pp.1540-1545
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• 2012

Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism, but the profile of proteins associated with progesterone synthesis in cyclic and pregnant corpus luteum (CL) is not well-known in cattle. In Experiment 1, plasma progesterone level was monitored in cyclic cows (n = 5) and pregnant cows (n = 6; until d-90). A significant decline in the plasma progesterone level occurred at d-19 of cyclic cows. Progesterone level in abbatoir-derived luteal tissues was also determined at d 1 to 5, 6 to 13 and 14 to 20 of cyclic cows, and d-60 and -90 of pregnant cows (n = 5 each). Progesterone level in d-60 CL was not different from those in d 6 to 13 CL and d-90 CL, although the difference between d 6 to 13 and d-90 was significant. In Experiment 2, protein expression pattern in CL at d-90 (n = 4) was compared with that in CL of cyclic cows at d 6 to 13 (n = 5). Significant changes in the level of protein expression were detected in 32 protein spots by two-dimensional polyacrylamide gel electrophoresis (2-DE), and 23 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Six proteins were found only in pregnant CL, while the other 17 proteins were found only in cyclic CL. Among the above 6 proteins, vimentin which is involved in the regulation of post-implantation development was included. Thus, the protein expression pattern in CL was disorientated from cyclic luteal phase to mid pregnancy, and alterations in specific CL protein expression may contribute to the maintenance of pregnancy in Korean native cows.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Journal of Life Science
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• v.25 no.12
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• pp.1370-1376
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• 2015

The 1, 1- diphenyl 2-picrylhyorazyl (DPPH) is a well-known radical and a trap (scavenger) for other radicals. Hyaluronidase (HAase) is an enzyme that depolymerizes the polysaccharide hyaluronic acid (HA) in the extracellular matrix of connective tissue. Lipoxygenase (LOX) enzyme was reported to convert the arachidonic, linoleic and other polyunsaturated fatty acid into biologically active metabolites involved in the inflammatory and immune responses. The purpose of the present study is to evaluate plant extracts as sources of natural antioxidants and to examine whether Achyranthes japonica having significant DPPH, HAase and LOX inhibitory activity. The inhibitory effect of HAase by A. japonica was assayed using a Morgan microplate assay. The antioxidant activity of the A. japonica extracts was measured on the basis of the scavenging activity of the stable 1, 1- diphenyl 2-picrylhyorazyl (DPPH) free radical. DPPH scavenging activity of matured roots of A. japonica was evaluated at 4.0 mg/ml was 87.8% and that of young roots was 86.2% at same concentration. The roots of A. japonica showed maximum inhibition of HAase activity (IC₅₀ = 27.7 μg/ml). The highest LOX inhibition was recorded in the root extract among three vegetative parts. Inhibition of HAase activity of roots may contribute towards the development of herbal medicines. Although percent inhibition of lipoxygenase by Achyranthes japonica for all young and matured groups for leaves, stems, and roots at different concentrations, there were not show a statistically significant difference (p<0.05).

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.2
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• pp.114-124
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• 2014

For classifying fire damaged areas and analyzing burn severity of two large-fire areas damaged over 100 ha in 2011, three methods were employed utilized supervised classification, unsupervised classification and Normalized Difference Vegetation Index (NDVI). In this paper, the post-fire imageries of SPOT were used to compute the Maximum Likelihood (MLC), Minimum Distance (MIN), ISODATA, K-means, NDVI and to evaluate large-scale patterns of burn severity from 1 m to 5 m spatial resolutions. The result of the accuracy verification on burn severity from satellite images showed that average overall accuracy was 88.38 % and the Kappa coefficient was 0.8147. To compare the accuracy between burn severity and field survey at Uljin and Youngduk, two large fire sites were selected as study areas, and forty-four sampling plots were assigned in each study area for field survey. The burn severities of the study areas were estimated by analyzing burn severity (BS) classes from SPOT images taken one month after the occurrence of the fire. The applicability of composite burn index (CBI) was validated with a correlation analysis between field survey data and burn severity classified by SPOT5, and by their confusion matrix. The result showed that correlation between field survey data and BS by SPOT5 were closely correlated in both Uljin (r = -0.544 and p<0.01) and Youngduk (r = -0.616 and p<0.01). Thus, this result supported that the proposed burn severity analysis is an adequate method to measure burn severity of large fire areas in Korea.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.338-342
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• 1994

Pulmonary clearance of Tc-99m-DTPA(PCD) has been used for the measurement of polmonary epithelial permeability. It has been reported to be increased not only in variety of polmonary diseases including ARDS, interstitial fibrosis, and smokers, but also in normal subjects on positive end expiratory pressure respirator, or after exercise. It was also noted that decrease of pulmonary blood flow due to pulmonary arterial obstruction results in delayed PCD. Normal range of PCD varies with institutes. We prospectively measured PCD in 17 normals (5 males and 12 females) consisted of staffs and trainees in the department of radiology of Kangnam St. Mary's hospital using original Bark Nebulizer (India). Age ranged from 32 to 43 years. 370 MBq of Tc-99m-DTPA was inhaled in supine position and supine posterior images were subsequently obtained with 1 min/frame, $64{\times}64$ matrix and word mode for 30min. Regions of interest were set on each lung, whole lungs, and upper, middle and lower thirds of right lung, respectively. Best fit regression curve was obtained by least square method from initial 7min after peak activity on each curve and time for half clearance of maximum activity (t1/2) was calculated. Mean t1/2 was $51{\pm}11.2min$ for whole lung. There was no significant difference between t1/ 2 of right and left lungs. Initial uptake was higher in the lower third and t1/2 was shorter in the lower third than in the upper third(P<0.05). We reviewed several reports on PCD and compared our data with the others. In this study, faster clearance in the lower third may be due to the position imaged with or the environment the subjects belong to, and further investigation is under way.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.151-162
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• 1997

Although modern versions of the traditional Von $Th{\ddot{u}}nen$ theory have contributed to a description of spatial organization in agriculture, they did not incorporate the market mechanism as an integral part of location theory. This deficiency has been indicated and new mathematical structure has been proposed elsewhere by the author. The closed model, which simultaneously considered a basic principle of supply and demand, exposed a computational complexity. Based on the problem, this study attempts to extend market mechanism in order to consider the influence of city (market) size in agricultural location theory. To theoretically explore the economic relationship in a location theory, this study simplifies agricultural activity as just two activities in one-dimensional spatial economy. The problem has been solved by equating total supply and demand of agricultural products, and then by determining each agricultural price from the relationship. All of the mathematical problems have been arranged in matrix form. First, the traditional model and closed model have been compared by quantitative comparative statics which provides the sensitivity test for each model. The results have shown that the traditional model shows a relatively excessive change in land use, besides the deficiency of a constant agricultural price. Second, the effects of the size of market town and its population increase were examined, using the closed model. In this case, the price of agricultural product is increased, and the land use is extended outward. This proves that locational rent is related to the expansion of land use. Third, environmental uncertainty was associated with the closed model, in order to further consider the difference of farmers attitude in strategic perspective. In this study, two extreme attitudes, which reflects the maximum average expected returns and the maximum guaranteed returns, were examined in their land use and their effects on the prices of agricultural products. It was shown that the two farmers attitudes can be interconnected with location theory. Due to the exogenous data, the differences in the area of land use and total quantities of agricultural products were not clearly shown in this study. However, it was shown that the land use pattern is very different. That is, maximum guaranteed return model reveals a mixed land use pattern around the market town. Basically, this study shows some spatial and economic implications related to Von $Th{\ddot{u}}nen$ model.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.391-398
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• 2001

This study was carried out to investigate the effects of storage temperature(5$\^{C}$ and 25$\^{C}$) and time(1, 24, 48 and 72hours) on the retrogradation characteristics of mungbean starch gels by using differential scanning calorimeter, rapid visco-analyzer, $\beta$-amylase method, X-ray diffractometer and scanning electron microscope. Endothermic peaks of gels stored at 5$\^{C}$ were shifted to the lower temperature than those stored at 25$\^{C}$ and endothermic enthalpy of gels stored at 5$\^{C}$ was greater than that stored at 25$\^{C}$. DSC thermograms showed that the retrogradation rate of gels stored at 5$\^{C}$ was higher than that shored at 25$\^{C}$. The pasting properties of the gels such as peak viscosity and final viscosity increased with increasing storage time except the gels stored at 25$\^{C}$ for 72 hours and this trend was more apparent at the storage temperature of 5$\^{C}$. The digestibility measured by $\beta$-amylase method decreased with increasing storage time and this trend was more apparent at the storage temperature of 5$\^{C}$. X-ray diffraction patterns of the gels stored at 5$\^{C}$ showed more distinct peak than those stored at 25$\^{C}$, but no difference was detected by the storage time. The microstucture of all the gels showed a well developed three dimensional network The network structure of the gels stored at 25$\^{C}$ formed a thick matrix after 72 hours and those stored at 5$\^{C}$ from the early stage of storage.