• Membrane Journal
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• v.34 no.1
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• pp.50-57
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• 2024

In this experiment, Pd-Ag-Cu membrane was manufactured using electroless plating on an α-Al₂O₃ support. Pd, Ag and Cu were each coated on the surface of the support through electroless plating and heat treatment was performed for 18 h at 500℃ in H₂ in the middle of electroless plating to form Pd alloy. The surface of the Pd-Ag-Cu membrane was observed through Scanning Electron Microscopy (SEM), and the thickness of the Pd membrane was measured to be 7.82 ㎛ and the thickness of the Pd-Ag-Cu membrane was measured to be 3.54 ㎛. Energy dispersive X-ray spectroscopy and X-ray diffraction analysis confirmed the formation of a Pd-Ag-Cu alloy with a composition of Pd-78wt%, Ag-8.81wt% and Cu-13.19wt%. The gas permeation experiment was conducted under the conditions of 350~450℃ and 1~4 bar in H₂ single gas and H₂/N₂ mixed gas. The maximum H₂ flux of the hydrogen separation membrane measured in H₂ single gas is 74.16 ml/cm²·min at 450℃ and 4 bar for the Pd membrane and 113.64 ml/cm²·min at 450℃ and 4 bar for the Pd-Ag-Cu membrane. In the case of the separation factor measured in H₂/N₂ mixed gas, separation factors of 2437 and 11032 were measured at 450℃ and 4 bar.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.458-464
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• 1998

Search for a new $\alpha$-methylene-$\gamma$-butyrolactone-bearing 6-substituted purine as a potental antitumor agent has led to synthesize seven, hitherto unreported, $5^1$-Methyl-$5^1$-[(6-substituted-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$- methylenetetrahydrofurans (H, Cl, l, $CH_3$, $NH_2$, SH, >C=O) (6a-g). These include $5^1$-Methyl-$5^1$-[(9H-purin-9-yl)methyll-$2^1$-oxo-$3^1$ -methylenetetrahydrofurans (6a), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydr ofurans (6b), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6c), $5^1$-Methyl-$5^1$-[(6-methyl-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6d), $5^1$-Methyl-$5^1$-[(9H-adenin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6e), $5^1$-Methyl-$5^1$-[(6-mercapto-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6f) and $5^1$-Methyl-$5^1$-[(9H-hypoxanthin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrof urans (6g) which were made by the Reformatsky-type reaction of ethyl $\alpha$-(bromomethyl) acrylate with the corresponding (6-substituted-9H-purin-9-yl)-2-propanone intermediates (5a-g). These ketone intermediates 5a-g, 1-(9H-purin-9-yl)-2-propanone (5a), 1-(6-chloro-9H-purin-9-yl)-2-propanone (5b), 1-(6-iodo-9H-purin-9-yi)-2-propanone (5c), 1-(6-methyl-9H-purin-9-yl)-2-propanone (5d), 1-(9H-adenin-9-yl)-2-propanone (Se), 1-(6-mercapto-9H-purin-9-yl)-2-propanone (5f), and 1-(9H-hypoxanthin-9-yl)-2-propanone (5g) were directly obtained by the alkylation of the 6-substituted purine bases with the chloroacetone in the presence of $K_2$$CO_3$ (or NaH) under DMF (or DMSO). The preliminary in vitro cytotoxcity assay for the synthetic .alpha.-methylene-y-butyro-lactone compounds (6a-g) were determined against three cell lines (PM-3A, P-388, and K-562) and showed the moderate antitumor activity ($IC_50$ ranged from 1.4 to 4.3 $\mu\textrm{g}$/ml) with the compound $5^1$-methyl-$5^1$ -[(9H-hypoxanthin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofuran (6g) showing the least antitumor activity.

• Journal of Biomedical Engineering Research
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• v.19 no.6
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• pp.617-622
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• 1998

A cryotherapy system using cold air was developed. The developed system had superior low-temperature characteristics with various flow rates and nozzle sizes, and used R-404A, as a coolant, which has no destructive effects of Ozone layers. Flow rates and the treatment time can be easily altered during the operation. In addition, and alarm system was designed for the overload, overheat, and over-charge of the machine. For clinical applications, skin temperatures, intra-articular temperatures of the knee joint and intra-muscluar temperatures of the gluteal muscles were measured during and after the cryotherapy. After a 5-minute therapy, skin and intra-articular temperatures decreased by $23.3{\pm}4.7 and 4.1 {\pm}1.0^{circ}C$, respectively. A 5-minute cryotherapy was good enough to maintain low intra-articular temperatures for 2-3 hours. Resting intra-muscular temperatures in 2, 4, and 6cm deep in the gluteal muscle were $36.5{\pm}1.2, 36.9{\pm}0.2, 37.1{\pm}0.2^{circ}C$, respectively (p<0.05). Lowest temperatures in 2, 4, and 6cm depth were $35.1{\pm}0.7, 36.2{\pm}0.4, 36.9{\pm}0.3^{circ}C$, respectively (p<0.05). Temperatures after a 2-hour cold air application on the skin and in the muscle in dept도 of 2, 4, and 6cm were $32.2{\pm}1.1, 36.2{\pm}0.5, 36.6{\pm}0.3, 36.9{\pm}0.3^{circ}C$respectively (p<0.05). Temperatures on the skin and in the muscle significantly decreased after 2 hours, compared with before cold air application (p<0.05). The intra-muscular temperature was changed more slowly than the skin temperature, and the deeper the muscle, the lesser temperature changes. The effect of a 5-minute cold air application lasts up to 2 hours, and it seems that the rebound-rise of the temperature dut to the reactive vasodilatation does not occur in the gluteal muscle.

• Korean Journal of Environment and Ecology
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• v.22 no.4
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• pp.396-408
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• 2008

Gwangtan-myeon, Paju-si, Gyeonggi-do was classified as a 4 grade age-class deciduous tree forest, however as a result of vegetation survey, this site was found to consist of natural forest with deciduous trees, thus causing difficulty in judging which age class it belongs to. Subsequently, the necessity of drawing up a detailed stock map plan was raised. For this reason, this research was designed to propose a mapping method for a detailed stock map plan based on a detailed survey on actual vegetation, vegetation structure, and analysis data on tree rings. The detailed analysis of actual vegetation pattern showed that there exist 22 patterns of vegetation, in which the natural forest has 11 patterns, such as Quercus mongolica forest and Q. variabilis forest, etc. while the artificial forest was found to have 6 patterns including Castanea crenata, etc. In order to verify their age-class, this research measured a tree age by collecting 42 quadrats and 89 specimen tree cores on the basis of a detailed actual vegetation map; as a result, an artificial forest and oak trees with small diameters located at low-lying areas, was categorized as 2-grade age class(covering 29.8%), and other areas were judged to be available for land use as 3-grade age-class(covering 57.6%) while the areas judged to be 4-or-more grade age-class (covering 8.8%) was impossible for land use because they are located on a steep slope ridge line on a boundary. In case a proposed site for a small-scale development is judged as a natural forest with deciduous trees as mentioned above, it is necessary that a detailed stock map plan should be drawn up through a detailed investigation into actual vegetation and analysis of plant gathering structure & specimen trees. A detailed stock map plan includes the data that makes it possible to comprehensively judge natural property, scarcity, and diversity of vegetation; thus, it is considered that a detailed stock map plan will be useful in judging the development propriety of a small-scale site.

• Information Systems Review
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• v.7 no.2
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• pp.101-115
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• 2005

IT companies make a lot of effort to share and utilize the experiences of their members and transform them into organizational knowledge as a competitive core. However they face a dilemma in that they have to spend time and financial resources to perform activities around knowledge management for the long-term gains, while carrying at field-work for making short-term profits. As an initial attempt to tackle this managerial problem, this paper tries to investigate the mechanism of knowledge management in a small IT company in Korea with a synthetic view-point using system dynamics simulation model. It depicts the dynamic behaviors of knowledge management and presents some findings of political leverage. Although this model has to be further replenished, the scheme for the dynamism of knowledge management and the findings presented in the paper could be useful for the decision makers, especially of knowledge-intensive organizations.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.299-306
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• 2008

Human pancreatic lipase is a digestive enzyme which is synthesized in pancreas, secreted into small intestine, and there hydrolyze the fat in food. Pancreatic lipase protein composes of catalytic domain and colipase-binding domain. In this research, the gene segments corresponding to total protein, catalytic domain, and co lipase-binding domain were cloned by PCR method, inserted into an expression vector, and then used to transform Escherichia coli BL21 (DE3). The recombinant proteins produced were purified and injected intramuscularly three times into laying hens. The egg yolk antibodies (IgY) were obtained from the egg yolks and tested for their antibody titer. Among three IgY, the IgY against colipase-binding domain showed the highest antibody titer. All three IgY had inhibitory effects on the porcine pancreatic lipase. Among them, the IgY against colipase-binding domain showed the highest inhibition effects. The fat diet with corn oil and IgY was administrated to the experimental rats and their blood compositions were examined with time course. The triglyceride concentration of treated rats was decrease meaningfully when compared with those of control rats. This suggested that the IgY against colipase-binding domain antigen inhibited pancreatic lipase in vivo.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.9
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• pp.1259-1265
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• 2015

The present study was performed to study the genetic relationship of productive life with production and type traits of Korean Holsteins at first three lactations. The data for the analysis from 56,054, 28,997, and 11,816 animals of first, second and third parity cows which were born from 2006 to 2011 were collected by Dairy Cattle Improvement Center, National Agricultural Co-operative Federation. Milk, protein and fat yields adjusted for 305 days and average somatic cell score considered as production traits and analyzed type traits were stature, strength, body depth, dairy form, rump angle, rump width, rear leg side view, foot angle, front attachment placement, rear attachment height, rear attachment width, udder cleft, udder depth, front teat placement and front teat length. A multi trait genetic analysis was performed using Wombat program with restricted maximum likelihood animal model composed of fixed effect of birth year, farm and the random effect of animal and random residual effect according to the traits. Heritability estimates of productive life were between 0.06 and 0.13. Genetic and phenotypic correlations between production and productive life traits ranged from 0.35 to 0.04 for milk, 0.16 to 0.05 for protein and 0.18 to 0.02 f 15-0034 (2nd) 150520 or fat. Somatic cells score showed a negative genetic and phenotypic correlation with productive life and also udder type traits, indicating that the selection for higher udder traits will likely to improve resistance to mastitis and persistence in the herd. Among all dairy form type traits, udder characters such as udder cleft showed a significant relationship with productive life. However, a specific change of heritabilities or correlations were not observed with the change of parity. Moreover, further studies are needed to further confirm the significance of the above traits and the effect of parity on above relationships in order to minimize both voluntary and involuntary culling rates while improving herd health and maintaining high yielding dairy cows.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.733-738
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• 2013

This study investigated the inhibitory effect of high hydrostatic pressure (HHP) treatments on histamine production in mackerel Scomber japonicus. Changes in viable cell counts, histamine contents, pH and VBN of mackerel fillet (stored at $4^{\circ}C$ for 25 days) were examined under HPP (200, 300, and 400 MPa). HPP treatments reduced viable cell counts by 2-3 log cycles during storage. Viable cells of mackerels treated with 400 MPa did not appear for 5 days. Histamine production was nearly suppressed by 300 and 400 MPa HPP treatments after 25 days. Furthermore, mackerels treated with HPP showed significantly lower VBN values compared with the control. Additionally, pH values were not affected by the treatments during storage periods. These results suggest that HPP treatment decreased histamine contents in mackerel muscles. Based on our results, HPP treatment may reduce scombroid fish poisoning by decreasing histamine production in mackerel during $4^{\circ}C$ storage.

• Journal of Environmental Health Sciences
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• v.37 no.4
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• pp.279-288
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• 2011

Objectives: This study investigated the levels and components of floor-settled dust in two elementary schools located at different sites (one near the Shihwa industrial complex and the other in a rural area) in order to evaluate the amounts of trace metal elements (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) and microorganisms. Methods: Over twenty settled-dust samples were collected from the two elementary schools. Trace metal elements were extracted from the dust using hydrochloric acid and nitric acid, and the amounts were measured by ICP-OES. Microbiological analysis was performed by bacterial culturing using R2A medium and denaturing gradient gel electrophoresis (DGGE). Results: The results showed that the amounts of three metal elements (Cr, Pb, and Zn) were significantly different between the schools (${\alpha}$=0.05, p<0.04). In addition, microbial communities in each school were highly correlated with one another. Among the identified microorganisms, a number of potentially opportunistic microorganisms, including antibiotic-resistant bacteria such as Acinetobacter baumannii, were found. Conclusions: This study will provide preliminary data for assessing levels and types of chemical and microbiological agents in elementary schools and for further evaluating human health risks associated with the agents.

• International Journal of Highway Engineering
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• v.17 no.3
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• pp.49-58
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• 2015

PURPOSES : The use of environmentally friendly construction methods has been recently encouraged to reduce fuel consumption and the effects of global warming. For this purpose, the roller compacted concrete pavement (RCCP) construction method has been developed. RCCP is more environmentally friendly and economically efficient than general concrete by reducing the amount of CO2 generated through the application of a smaller amount of cement. RCCP has a number of advantages such as an easy construction method, low cost, high structural hydration performance, and aggregate interlocking. However, mix design standards and construction guidelines of RCCP are required for domestic application. In addition, a study on aggregate selection, which has an effect on the characteristics of RCCP, is necessary owing to a limited number of researches. Thus, the aggregate effect on the performance of RCCP in securing the required strength and workability was evaluated in consideration of domestic construction. METHODS : Sand and coarse aggregates of both 19mm and 13mm in maximum size were used in this study. Four types of aggregate gradations (s/a = 30%, 58%, and 70% for the sand and coarse aggregate of 19mm in maximum size, and s/a = 50% for a combination of the three types of aggregates) were set up to investigate the effects of the PCA band on the RCC characteristics. The conditions of s/a = 30% and 70% were evaluated to check the gradation effect outside of the recommended band. The conditions of s/a = 58% and 50% were used because they are the optimum combination of the two and three types of aggregates, respectively. RCCP gradation band was suggested gradation with a proper construction method of RCCP by synthetically comparing and analyzing the correlation of optimum water content, maximum dry density, and strength of requirements through its consistency and compaction test. RESULTS : The lower and upper limit lines are insufficient to secure a relatively strong development and workability compared to an aggregate gradation in the RCCP gradation band region. On the other hand, the line in the RCCP gradation band and the 0.45 power curve in the RCCP gradation band region were satisfactory, ensuring the required strength and workability. CONCLUSIONS : The suitable aggregate gradation on RCCP process should meet the RCCP gradation band area; however, fine particles passing through a #60 sieve do not need to be within the recommended gradation band because the influence of this region on such fine particles is small.