• Electronics and Telecommunications Trends
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• v.24 no.1
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• pp.50-58
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• 2009

FTTH 망에 널리 적용되고 있는 PON 기술은 OPEX 비용을 최소화 하면서 가입자에게 많은 대역을 제공할 수 있는 매력적인 기술이다. 이러한 대표적인 PON 기술에는 가입자간 시분할 방법에 의하여 데이터를 전송하는 TDMA-PON이 있으며, 여기에는 IEEE802.3의 EPON과 ITU-T/FSAN의 GPON이 포함된다. 향후 IPTV 등을 포함한 신규 서비스 등장과 광대역을 요구하는 미래 가입자 서비스를 충족시키기 위해서 PON 기술은 지속적으로 발전할 것으로 예상된다. 본 고에서는 IEEE802.3과 ITU-T/FSAN에서 추진중인 차세대 광가입자망 표준화 활동 동향을 소개한다.

• Archives of Pharmacal Research
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• v.18 no.3
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• pp.146-152
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• 1995

To achieve a better understanding of the effects on behavioral safety caused by possible neuroprotective doses (50 mg/kg, p.o.) of dextromethorphan HBr (DM), several motor activity measures were monitored in two generations of mice through a long-term period of ten months. Adult male mice (G1), in the presence of DM, developed behavioral tolerance after an initial suppression period. Prenatally exposed, second generation (G2) mice formed two groups, prenatal exposure alone (G2C) and prenatally exposed with additional postnatal exposure (G2T). In the presence of DM, group G2T was characterized by significant behavioral impairment; while G2C exhibited behavioral activation. These results suggest that more attention should be given to the prenatal effects of DM on a developing organism.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.135-145
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• 1998

Bupleury radix has been used for the treatment of fever, liver disease, inflammation in traditional medicine. The present study was carried out to evaluate the antioxidant effects of Bupleury radix aqua-acupuncture solution (BRAS) in vitro. Oxygen derived free radicals produced in the course of normal aerobic life, such as superoxide anion radical($O_2^-$ ), hydroxyl radicaI( OH), hydrogen peroxide($H_2O_2$) and singlet oxygen($^1O_2$) can attack polyunsaturated fatty acid in cell membranes, enzymes, other cell compounds, and give rise to lipid peroxidation, DNA damage, lipofuscin accumulation, structure alteration of cell membrane and cell death. In this study, antioxidant effects of BRAS on lipid peroxidation were determined according to the method of TBA. BRAS inhibited markedly peroxidation of linoleic acid during the autoxidation, and also inhibited lipid peroxidation induced by hydroxyl radical derived from $H_2O_2-Fe^{2+}$ in rat liver homogenate. And BRAS showed 30% scavenging effect on DPPH radical, also exhibited a 30% inhibitory effect on superoxide generation from xanthine-xanthine oxidase system. In addition, BRAS protected the cell death induced by tert-butyl hydroperoxide(t-BHP) and significantly increased cell viability in the normal rat liver cell(Ac2F).

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.43.2-44
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• 2018

One of the keys to interpreting the characteristics and evolution of interstellar medium in the Milky Way is to understand the distribution of hot gas ($10^5-10^6K$). Gases in this phase are difficult to observe because they are in low density and lack of easily observable tracers. Hot gases are observed mainly in the emission of the FUV ($912-1800{\AA}$), EUV ($80-912{\AA}$), and X-rays (T> $10^6K$) of which attenuation is very high. Of these, FUV emission lines originated from high-stage ions such as O VI and C IV can be the most effective tracers of hot gases. To determine the spatial distribution of O VI and C IV emissions, we have analyzed the spectra obtained from FIMS (Far-ultraviolet IMaging Spectrograph), which covers about 80 percent of the sky. The hot gas volume filling factor, which varies widely from 0.1 to 0.9 depending on the supernova explosion frequency and the evolution model, has been calculated from the O VI and C IV maps. The hot gas generation models has been verified from the global distribution of O VI and C IV emissions, and a new complementary model has been proposed in this study.

• Toxicological Research
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• v.34 no.2
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• pp.103-110
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• 2018

Environmental stimuli can lead to the excessive accumulation of reactive oxygen species (ROS), which is one of the risk factors for premature skin aging. Here, we investigated the protective effects of $7-MEGA^{TM}$ 500 (50% palmitoleic acid, 7-MEGA) against oxidative stress-induced cellular damage and its underlying therapeutic mechanisms in the HaCaT human skin keratinocyte cell line (HaCaT cells). Our results showed that treatment with 7-MEGA prior to hydrogen peroxide ($H_2O_2$)-induced damage significantly increased the viability of HaCaT cells. 7-MEGA effectively attenuated generation of $H_2O_2$-induced reactive oxygen species (ROS), and inhibited $H_2O_2$-induced inflammatory factors, such as prostaglandin $E_2$ ($PGE_2$), tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), and $interleukin-1{\beta}$ ($IL-1{\beta}$). In addition, cells treated with 7-MEGA exhibited significantly decreased expression of matrix metalloproteinase-1 (MMP-1) and increased expression of procollagen type 1 (PCOL1) and Elastin against oxidative stress by $H_2O_2$. Interestingly, these protective activities of 7-MEGA were similar in scope and of a higher magnitude than those seen with 98.5% palmitoleic acid (PA) obtained from Sigma when given at the same concentration (100 nL/mL). According to our data, 7-MEGA is able to protect HaCaT cells from $H_2O_2$-induced damage through inhibiting cellular oxidative stress and inflammation. Moreover, 7-MEGA may affect skin elasticity maintenance and improve skin wrinkles. These findings indicate that 7-MEGA may be useful as a food supplement for skin health.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.439-446
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• 2014

Many studies on methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock industries have revealed that livestock production directly contributes to greenhouse gas (GHG) emissions through enteric fermentation and manure management, which causes negative impacts on animal environment sustainability. In the present study, three essential values for GHG emission were measured; i.e., i) maximum $CH_4$ producing capacity at mesophilic temperature ($37^{\circ}C$) from anaerobically stored manure in livestock category ($B_{0,KM}$, Korean livestock manure for $B_0$), ii) $EF_{3(s)}$ value representing an emission factor for direct $N_2O$ emissions from manure management system S in the country, kg $N_2O-N$ kg $N^{-1}$, at mesophilic ($37^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures, and iii) $N_{ex(T)}$ emissions showing annual N excretion for livestock category T, kg N $animal^{-1}$ $yr^{-1}$, from different livestock manure. Static incubation with and without aeration was performed to obtain the $N_2O$ and $CH_4$ emissions from each sample, respectively. Chemical compositions of pre- and post- incubated manure were analyzed. Contents of total solids (% TS) and volatile solid (% VS), and the ratio of carbon to nitrogen (C/N) decrease significantly in all the samples by C-containing biogas generation, whereas moisture content (%) and pH increased after incubation. A big difference of total nitrogen content was not observed in pre- and post-incubation during $CH_4$ and $N_2O$ emissions. $CH_4$ emissions (g $CH_4$ kg VS-1) from all the three manures (sows, layers and Korean cattle) were different and high C/N ratio resulted in high $CH_4$ emission. Similarly, $N_2O$ emission was found to be affected by % VS, pH, and temperature. The $B_{0,KM}$ values for sows, layers, and Korean cattle obtained at $37^{\circ}C$ are 0.0579, 0.0006, and 0.0828 $m^3$ $CH_4$ kg $VS^{-1}$, respectively, which are much less than the default values in IPCC guideline (GL) except the value from Korean cattle. For sows and Korean cattle, $N_{ex(T)}$ values of 7.67 and 28.19 kg N $yr^{-1}$, respectively, are 2.5 fold less than those values in IPCC GL as well. However, $N_{ex(T)}$ value of layers 0.63 kg N $yr^{-1}$ is very similar to the default value of 0.6 kg N $yr^{-1}$ in IPCC GLs for National greenhouse gas inventories for countries such as South Korea/Asia. The $EF_{3(s)}$ value obtained at $37^{\circ}C$ and $55^{\circ}C$ were found to be far less than the default value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.578-580
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• 2017

IoT technology poses a lot of security threats. Various algorithms are thus employed in ensuring security of transactions between IoT devices. Advanced Encryption Standard (AES) has gained huge popularity among many other symmetric key algorithms due to its robustness till date. This paper presents a hardware based implementation of the AES algorithm. We present a four-stage pipelined architecture of the encryption and key generation. This method allowed a total plain text size of 512 bits to be encrypted in 46 cycles. The proposed hardware design achieved a maximum frequency of 1.18GHz yielding a throughput of 13Gbps and 800MHz yielding a throughput of 8.9Gbps on the 65nm and 180nm processes respectively.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.323-330
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• 2008

The study presents the results of 1,4-dioxane degradation using zero valent (Fe$^0$) or Fe$^{2+}$ ions with and without UV. During the reaction, the change of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)], the concentration ratio of ferrous ion to total iron ion in solution was measured. Less than 10% degradation of 1,4-dioxane was observed by UV-only, Fe$^0$-only, and Fe$^{2+}$-only conditions, and also the changes of [Fe$^{2+}$] and [Fe$^{2+}$]/[Fe(t)] were minimal in each reaction. However, the oxidation of Fe$^0$ was enhanced with the irradiation of UV by approximately 25% and the improvement of 1,4-dioxane degradation was observed. Fenton reaction ($Fe^{2+}+H_2O_2$) showed higher degradation efficiency of 1,4-dioxane until 90 min, which of the degradation was stopped after that time. In the reaction of Fe$^{2+}$ and UV, the ratio of [Fe$^{2+}$]/[Fe(t)] decreased then slowly increased after a certain time indicating the reduction of Fe3+ to Fe$^{2+}$. In case of Fe$^0$ in the presence of UV, the first-order rate constant was found to be 1.84$\times$10$^{-3}$ min$^{-1}$ until 90 min, and then changed to 9.33$\times$10$^{-3}$ min$^{-1}$ when the oxidation of Fe$^{2+}$ mainly occurred. In this case [Fe$^{2+}$]/[Fe(t)] kept decreasing for the reaction. However, the addition of perchlortae (ClO$_4^-$) in the reaction of Fe$^0$ and UV induced the continuous increase of [Fe$^{2+}$]/[Fe(t)] ratio. The results mean the primary degradation factor of 1,4-dioxane is the oxidation by the radicals generated from the redox reaction between Fe$^{2+}$ and Fe$^{3+}$. Also, both UV and ClO$_4^-$ played the role inducing the reduction of Fe$^{3+}$, which is important to degrade 1,4-dioxane by enhancing the generation of radicals.

• Conservation Science in Museum
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• v.7
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• pp.25-31
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• 2006

We performed the conservation treatment for Bigyeokchinjeonnoe (A kind of time bomb in the Joseon Dynasty) excavated from Hwawangsanseong Fortress in Changnyeong-gun, Gyeongsangnam-do Province. Part of the Bigyeokchinjeonnoe has been lost; we did not restore the lost part so that one can observe the inside through it. The results of X-ray investigation and C. T (Computed Tomography) scan proved the generation of many blowholes around the molding line during the casting process; a hole in the casting mold to maintain inner mold during casting was identified on the surface and traces of fortifying this part with iron plate were also identified. The main ingredients of the blue corrosion on the surface were identified as O, Fe, P, Si and Al by SEM/EDS analysis. The result of XRD analysis identified the blue corrosion as vivianite [Fe₃(PO₄)₂·8H₂O]. The metal structure clarified its material was gray cast iron.

• Horticultural Science & Technology
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• v.34 no.1
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• pp.154-162
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• 2016

The aim of this study was to develop a transgenic petunia with enhanced resistance to sulfur dioxide ($SO_2$) gas by stacking two genes, SOD2 and NDPK2, which are both known to confer resistance to abiotic stresses. The first-generation hybrids ($TF_1$) were obtained through reciprocal crosses between an SOD2-transgenic line SOD2-2-1-1-35($T_4$)[S($T_4$)] and an NDPK2-transgenic line NDPK2-7-1($T_2$)[N7-1($T_2$)]. Approximately 32.1-73.0% of the first-generation hybrids ($TF_1$) carried both SOD2 and NDPK2 genes. These hybrids showed 2.6 and 5.1 times less damage than hybrids carrying only SOD2 or NDPK2 genes, respectively, when they were treated with $SO_2$ gas at 30 ppm. This confirmed that the heterozygous hybrids were more resistant to $SO_2$ than the hybrids carrying either one of the resistance genes. Second-generation hybrids ($TF_2$) were obtained by selfing the $TF_1$ individuals. We confirmed the expression of the stacked genes in the $TF_2$ hybrids by phenotypic observation of their response to $SO_2$ gas at 30 ppm as well as using RT-qPCR and photosynthetic efficiency.