• Biomolecules & Therapeutics
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• v.16 no.3
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• pp.270-276
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• 2008

In this study we investigated the effects of Magnolia Bark (MB) extract and its constituents, such as honokiol and magnolol, on gastritis in rats and the growth of human gastric cancer cells. The MB extract, honokiol, and magnolol showed the acid-neutralizing capacities, the antioxidant activities, and the inhibitory effect on the growth of Helicobacter pylori (H. pylori.) at the dose of $50\;{\mu}g/ml$ and over, which is equivalent to that of ampicillin ($100\;{\mu}g/ml$). Honokiol and magnolol had no significant cytotoxicity to human gastric caner cells (AGS and SNU638). However, the MB extract had cytotoxic activity against AGS gastric cancer cell. The MB extract, honokiol, and magnolol significantly inhibited HCI-ethanol-induced gastric lesions without clear change of mucus content. In pylorus ligated rats, honokiol significantly decreased the volume of gastric secretion and gastric acid output, and increased the pH. Magnolol increased the mucus content to almost the same as the control group at oral doses of 50 mg/kg. Therefore, we could guess that antigastritic action of honokiol and magnolol may be associated with the antioxidant activities, acid-neutralizing capacities, inhibition of secretion in gastric acid, and anti-H. pylori action. From these results, we could suggest that MB extract and its constituents, such as honokiol and magnolol, may be useful for the treatment and/or protection of gastritis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1369-1374
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• 2021

Recently, controversy has been raised over the security and safety of Chinese-made network equipment (Huawei 5G), apps (TikTok, etc.). In particular, according to the results of the Ministry of Defense investigation in 2020, malicious codes were found in CCTVs made in China that were delivered as military surveillance equipment used as a coast guard system, and specific information was remotely transmitted to a Chinese server. The safety issues of these Chinese security products can be questioned as being systematically led by the state rather than by companies or individuals. In this paper, we perform network and process level analysis of 360 Total Security(360 TS), a Chinese antivirus software. In addition, it compares and analyzes the domestic cloud-based vaccine V3 Lite product. Through this, the safety of Chinese security solutions is checked and information leakage and risks are suggested.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.237-242
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• 1998

The goal of this work was to optimize the liquid scintillation counting techniques for the determination of C-14 in environmental samples such as biological and air samples. Carbon-14 activities in most environmental samples were measured with direct $CO_2$ absorption method. The highest figure of merit was found through the variation of Carbosorb $E^{TM}$ and Permatluor $V^{TM}$ ratio, in the measurement windows. The best condition was 1:1 volume ratio. Average 2.35 g of $CO_2$ was reproducibly absorbed in the 20 ml mixture within 40 min. The counting efficiency determined by repeated analysis of NIST oxalic acid standard and the background count rate were measured to be $58.8{\pm}1.4%$ and $1.88{\pm}0.06\;cpm$, respectively in case of saturated solution. The correction curves of counting efficiency for partially saturated solutions and for saturated solutions with quenching were prepared, respectively. The overall uncertainty of the sample specific activity for near background levels was estimated to be about 7 % for 4 hours counting at 95 % confidence level. The long-term stability of samples has been checked for all the counting techniques over a two week periods, and no apparent change in counting efficiency and background level was found at that time.

• Journal of Life Science
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• v.27 no.8
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• pp.909-918
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• 2017

Ice plant (Mesembryanthemum crystallinum L.) was fermented in brine in the form of mulkimchi (IPMB), and its contents of organic acid and cyclitols and biological activities were compared with those before fermentation. The pH of the IPMB continuously decreased until the sixth day of fermentation. The lactic acid yield was greatest on the fourth day. D-pinitol in ice plant mulkimchi solids (IPMS) decreased during fermentation. However, myo-inositol and D-chiro-inositol increased. The radical scavenging activities of ABTS and DPPH, in addition to the activity of FRAP, of the IPMS extract were generally higher after fermentation, with the activities highest on the fifth ($79.09{\pm}0.69%$), fourth ($87.55{\pm}1.21%$), and sixth ($78.72{\pm}0.99%$) days of fermentation, respectively, when treated with 1 mg/ml of the extract. As shown by a lipid/MA assay, antioxidant activity was generally higher after fermentation. The viability of BNL CL.2 cells damaged by t-BHP, $H_2O_2$, and ethanol was $14.19{\pm}0.98$, $13.80{\pm}2.25$, and $25.89{\pm}2.90%$, respectively. When treated with $200{\mu}g/ml$ of IPMS extract, the cell viability was $57.06{\pm}4.52%$ on the first day, and $66.06{\pm}1.36%$ on the fourth day, and $50.07{\pm}04.85%$ on the sixth day of fermentation. Hepatocyte protective effects did not increase significantly after fermentation. ${\alpha}-glucosidase$ inhibitory activity was quite high, with a range of $83.52{\pm}2.69$ to $92.79{\pm}2.16%$, and the activity increased gradually in all the groups over the fermentation period. There was no clear correlation between ${\alpha}-amylase$ inhibitory activity and fermentation.

• Microbiology and Biotechnology Letters
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• v.35 no.2
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• pp.158-162
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• 2007

Methicillin-resistant Staphylococcus aureus (MRSA) is one of a major nosocomial pathogen worldwide and the emergence of this strain has become a major clinical problem. This study was performed for 13 hospitals with more than 400 beds in the country by collecting samples including hands and nasal cavities of doctors, nurses, guardians and patients. Also, additional 320 samples of hands and nasal cavities of 160 community resident in different locations and regions were collected. In all of medical environments and community resident, 625 strains of S. aureus were detected. Among 625 strains of S. aureus, 585 strains(93.6%) showed the resistance to at least one kind of antimicrobial and 112 strains (17.9%) showed multi-drug resistance with the resistance to 4 different types of antimicrobial. Total 152 MRSA strains (24.3%) were isolated from medical environment and community resident. In nasal cavity and hand, 49 MRSA (19.4%) and 103 (27.6%) MRSA were isolated, respectively Minimum inhibitory concentration(MIC) test is used to measure for susceptibility of MRSA isolated to oxacillin. At a concentration $16{\mu}g/ml$ of oxacillin, 11 strains were inhibited. 32 strains at $32{\mu}g/ml$, 41 strains at $64{\mu}g/ml$, 3 strains at $128{\mu}g/ml$, 25 stains at $256{\mu}g/ml$ and 40 strains at over $256{\mu}g/ml$ were inhibited. It was considered that medical environment showed higher than livestock and marine environments in MRSA detection rate.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.377-392
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• 2017

A set of BFM (Brute Force Method) simulations with the CMAQ (Community Multiscale Air Quality) model were conducted in order to estimate self-contributions and conversion rates of PPM (Primary $PM_{2.5}$), $NO_x$, $SO_2$, $NH_3$, and VOC emissions to $PM_{2.5}$ concentrations over the SMA (Seoul Metropolitan Area). CAPSS (Clean Air Policy Support System) 2013 EI (emissions inventory) from the NIER (National Institute of Environmental Research) was used for the base and sensitivity simulations. SCCs (Source Classification Codes) in the EI were utilized to group the emissions into area, mobile, and point source categories. PPM and $PM_{2.5}$ precursor emissions from each source category were reduced by 50%. In turn, air quality was simulated with CMAQ during January, April, July, and October in 2014 for the BFM runs. In this study, seasonal variations of SMA $PM_{2.5}$ self-sensitivities to PPM, $SO_2$, and $NH_3$ emissions can be observed even when the seasonal emission rates are almost identical. For example, when the mobile PPM emissions from the SMA were 634 TPM (Tons Per Month) and 603 TPM in January and July, self-contributions of the emissions to monthly mean $PM_{2.5}$ were $2.7{\mu}g/m^3$ and $1.3{\mu}g/m^3$ for the months, respectively. Similarly, while $NH_3$ emissions from area sources were 4,169 TPM and 3,951 TPM in January and July, the self-contributions to monthly mean $PM_{2.5}$ for the months were $2.0{\mu}g/m^3$ and $4.4{\mu}g/m^3$, respectively. Meanwhile, emission-to-$PM_{2.5}$ conversion rates of precursors vary among source categories. For instance, the annual mean conversion rates of the SMA mobile, area, and point sources were 19.3, 10.8, and $6.6{\mu}g/m^3/10^6TPY$ for $SO_2$ emissions while those rates for PPM emissions were 268.6, 207.7, and 181.5 (${\mu}g/m^3/10^6TPY$), respectively, over the region. The results demonstrate that SMA $PM_{2.5}$ responses to the same amount of reduction in precursor emissions differ for source categories and in time (e.g. seasons), which is important when the cost-benefit analysis is conducted during air quality improvement planning. On the other hand, annual mean $PM_{2.5}$ sensitivities to the SMA $NO_x$ emissions remains still negative even after a 50% reduction in emission category which implies that more aggressive $NO_x$ reductions are required for the SMA to overcome '$NO_x$ disbenefit' under the base condition.

• Information Systems Review
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• v.10 no.3
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• pp.21-38
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• 2008

After the introduction stage, Korean mobile game market is approaching to the growing stage leading mobile contents market. The environment for the mobile contents business is getting better by the expansion of the 3G mobile networks and the enhancement of the mobile devices. In this research, at a content level, not a service level, market success factors of mobile games and the differences by genres and their changes over time were investigated through the analysis of the real market data of mobile games launched by a Korean mobile carrier. The most important factors for market success, especially for the genres of RPG/Tycoon/Simulation and Shooting/Action/Arcade, were found to be the 'design' factor and its effect turned to be getting stronger as time goes by after the launch. Consumers' purchase rate was actually higher for the mobile games of popular genres or in relation with socially popular subject matters. Also 'design' and 'creativity' factors which are related to the quality of contents, have gotten more important over time. One of the most interesting results was that there existed a "blue ocean" genres like Sports/Racing/Leisure which had a steady demand but not many competing games. In the analysis of the 'convenience' factor, one interesting implication for mobile game producers was that there exists a trade off between the ease of initial adoption and the steady sales of a mobile game.

• The Korean Journal of Malacology
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• v.29 no.4
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• pp.313-323
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• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.317-328
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• 2017

This paper presents design and specific absorption rate analysis of a 2.4 GHz wearable patch antenna on a conventional and electromagnetic bandgap (EBG) ground planes, under normal and bent conditions. Wearable materials are used in the design of the antenna and EBG surfaces. A woven fabric (Zelt) is used as a conductive material and a 3 mm thicker Wash Cotton is used as a substrate. The dielectric constant and tangent loss of the substrate are 1.51 and 0.02 respectively. The volume of the proposed antenna is $113{\times}96.4{\times}3mm^3$. The metamaterial surface is used as a high impedance surface which shields the body from the hazards of electromagnetic radiations to reduce the Specific Absorption Rate (SAR). For on-body analysis a three layer model (containing skin, fats and muscles) of human arm is used. Antenna employing the EBG ground plane gives safe value of SAR (i.e. 1.77W/kg<2W/kg), when worn on human arm. This value is obtained using the safe limit of 2 W/kg, averaged over 10g of tissue, specified by the International Commission of Non Ionization Radiation Protection (ICNIRP). The SAR is reduced by 83.82 % as compare to the conventional antenna (8.16 W/kg>2W/kg). The efficiency of the EBG based antenna is improved from 52 to 74 %, relative to the conventional counterpart. The proposed antenna can be used in wearable electronics and smart clothing.

• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.651-657
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• 1994

To assess quantitatively the association between benzene exposure and leukemia, we examined the mortality rate of a cohort with occupational exposure to benzene. Cumulative exposure for each cohort member was estimated from historical air-sampling data and, when no sampling data existed, from interpolation on the basis of existing data. The overall standardized mortality ratio (a measure of relative risk multiplied by 100) for leukemia was 337 (95 percent confidence interval, 154 to 641), and that for multiple myeloma was 409 (95 percent confidence interval, 110 to 1047). With stratification according to levels of cumulative exposure, the standardized mortality ratios for leukemia increased from 109 to 322, 1186, and 6637 with increases in cumulative benzene exposure from less than 40 parts per million-years (ppm-years), to 40 to 199, 200 to 399, and 400 or more. respectively. A cumulative benzene exposure of 400 ppm years is equivalent to a mean annual exposure of 10 ppm over a 40-year working lifetime; 10 ppm is the currently enforceable standard in the United States for occupational exposure to benzene. To examine the shape of the exposure-response relation, we performed a conditional logistic-regression analysis, in which 10 controls were matched to each cohort member with leukemia. From this model, it can be calculated that protection from benzene induced leukemia would increase exponentially with any reduction in the permissible exposure limit.