• Journal of Communications and Networks
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• v.17 no.1
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• pp.58-66
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• 2015

Aeronautical communication networks (ACN) is an emerging concept in which aeronautical stations (AS) are considered as a part of multi-tier network for the future wireless communication system. An AS could be a commercial plane, helicopter, or any other low orbit station, i.e., Unmanned air vehicle, high altitude platform. The goal of ACN is to provide high throughput and cost effective communication network for aeronautical applications (i.e., Air traffic control (ATC), air traffic management (ATM) communications, and commercial in-flight Internet activities), and terrestrial networks by using aeronautical platforms as a backbone. In this paper, we investigate the issues about connectivity, throughput, and delay in ACN. First, topology of ACN is presented as a simple mobile ad hoc network and connectivity analysis is provided. Then, by using information obtained from connectivity analysis, we investigate two communication models, i.e., single-hop and two-hop, in which each source AS is communicating with its destination AS with or without the help of intermediate relay AS, respectively. In our throughput analysis, we use the method of finding the maximum number of concurrent successful transmissions to derive ACN throughput upper bounds for the two communication models. We conclude that the two-hop model achieves greater throughput scaling than the single-hop model for ACN and multi-hop models cannot achieve better throughput scaling than two-hop model. Furthermore, since delay issue is more salient in two-hop communication, we characterize the delay performance and derive the closed-form average end-to-end delay for the two-hop model. Finally, computer simulations are performed and it is shown that ACN is robust in terms of throughput and delay performances.

• Bulletin of the Korean Chemical Society
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• v.23 no.9
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• pp.1315-1327
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• 2002

The model compounds, 8-methoxypsoralen-CH2O(CH2)n-adenine (MOPCH2OCnAd, n=2, 3, 5, 6, 8, and 10) in which 5 position of 8-methoxypsoralen (8-MOP) is linked by various lengths of polymethylene bridge to N9 of adenine. UV absorption spectra are identical with the sum of MOPCH2OC3 and adenine absorption spectra. Solvent effects on the UV absorption and fluorescence emission spectra indicate that the lowest excited singlet state is the $(\pi${\rightarrow}$\pi*)$ state. The spectral characteristics of the fluorescence of MOPCH2OCnAd are strongly dependent upon the nature of the solvents. The fluorescence emission spectra in aprotic solvents are broad and structureless due to the excimer formation through the folded conformation accelerated by hydrophobic ${\pi}-{\pi}$ stacking interaction. Increasing polarity of the protic solvents leads to higher population of unfolded conformation stabilized through favorable solvation and H-bonding, and consequently to an increase in the fluorescence intensity, fluorescence lifetime, and a shift of fluorescence maximum to longer wavelengths. The decay characteristics of the fluorescence in polar protic solvents shows two exponential decays with the lifetimes of 0.6-0.8 and 1.6-1.9 ns in 5% ethanol/water, while MOPCH2OC3 shows 0.5 and 1.7 ns fluorescence lifetimes. The long-lived component of fluorescence can be attributed to the relaxed species (i.e., the species for which the solvent reorientation (or relaxation) has occurred), while the short-lived components can be associated with the unrelaxed, or only partially relaxed, species.

• BMB Reports
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• v.52 no.7
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• pp.439-444
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• 2019

Although hypoxic/ischemic injury is thought to contribute to the incidence of Alzheimer's disease (AD), the molecular mechanism that determines the relationship between hypoxia-induced ${\beta}$-amyloid ($A{\beta}$) generation and development of AD is not yet known. We have now investigated the protective effects of N,4,5-trimethylthiazol-2-amine hydrochloride (KHG26702), a novel thiazole derivative, on oxygen-glucose deprivation (OGD)-reoxygenation (OGD-R)-induced $A{\beta}$ production in SH-SY5Y human neuroblastoma cells. Pretreatment of these cells with KHG26702 significantly attenuated OGD-R-induced production of reactive oxygen species and elevation of levels of malondialdehyde, prostaglandin $E_2$, interleukin 6 and glutathione, as well as superoxide dismutase activity. KHG26702 also reduced OGD-R-induced expression of the apoptotic protein caspase-3, the apoptosis regulator Bcl-2, and the autophagy protein becn-1. Finally, KHG26702 reduced OGD-R-induced $A{\beta}$ production and cleavage of amyloid precursor protein, by inhibiting secretase activity and suppressing the autophagic pathway. Although supporting data from in vivo studies are required, our results indicate that KHG26702 may prevent neuronal cell damage from OGD-R-induced toxicity.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.04a
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• pp.77-90
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• 2006

Beta-amyloid peptide (A$\beta$) is a major component of senile plaques and its aggregation is considered to play a critical role in pathogenesis of Alzheimer's disease (AD). Aggregation of A$\beta$ could result from both increased synthesis and decreased degradation of A$\beta$. Our laboratory is interested in understanding the mechanism of A$\beta$ degradation in brain. Recently our laboratory identified a bacterial gene (SKAP) from Streptomyces sp KK565 whose protein product has an activity to cleave A$\beta$ and thus reduce the A$\beta$-induced neurotoxicity. The sequence analysis showed that this gene was closely related to aminopeptidase. Maldi-Tof analysis showed that the recombinant SKAP protein expressed in E. coli cleaves both A$\beta$ 40 and A$\beta$ 42 at the N-terminal of A$\beta$ while an aminopeptidase from Streptomyces griseus (SGAP) cleaves at the C-terminal. We also identified a mammalian homolog of SKAP and the recombinant mammalian protein expressed in Sf-9 insect cells showed a similar proteolytic activity to SGAP, cutting A$\beta$ at the C-terminus. I well discuss the detailed mechanism of the enzyme action and its functional implication in AD.

• Wind and Structures
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• v.31 no.4
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• pp.299-309
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• 2020

In this study, wind data such as speeds, loads and potential of Muğla which is located in the southwest of Turkey were statistically analyzed. The wind data which consists of hourly wind speed between 2010 and 2013 years, was measured at the 10-meters height in four different ground stations (Datça, Fethiye, Marmaris, Köyceğiz). These stations are operated by The Turkish State Meteorological Service (T.S.M.S). Furthermore, wind data was analyzed by using Log-Normal and Gamma distributions, since these distributions fit better than Weibull, Normal, Exponential and Logistic distributions. Root Mean Squared Error (RMSE) and the coefficients of the goodness of fit (R²) were also determined by using statistical analysis. According to the results, extreme wind speed in the research area was 33 m/s at the Datça station. The effective wind load at this speed is 0.68 kN/㎡. The highest mean power densities for Datça, Fethiye, Marmaris and Köyceğiz were found to be 46.2, 1.6, 6.5 and 2.2 W/㎡, respectively. Also, although Log-normal distribution exhibited a good performance i.e., lower AD (Anderson - Darling statistic (AD) values) values, Gamma distribution was found more suitable in the estimation of wind speed and power of the region.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.64-68
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• 2007

This paper describes the development of RF front.end equipment of a wide band high precision satellite navigation receiver to be able to receive the currently available GPS navigation signal and the GALILEO navigation signal to be developed in Europe in the near future. The wide band satellite navigation receiver with high precision performance is composed of L - band antenna, RF/IF converters for multi - band navigation signals, and high performance baseband processor. The L - band satellite navigation antenna is able to be received the signals in the range from 1.1 GHz to 1.6 GHz and from the navigation satellite positioned near the horizon. The navigation signal of GALILEO navigation satellite consists of L1, E5, and E6 band with signal bandwidth more than 20 MHz which is wider than GPS signal. Due to the wide band navigation signal, the IF frequency and signal processing speed should be increased. The RF/IF converter has been designed with the single stage downconversion structure, and the IF frequency of 140 MHz has been derived from considering the maximum signal bandwidth and the sampling frequency of 112 MHz to be used in ADC circuit. The final output of RF/IF converter is a digital IF signal which is generated from signal processing of the AD converter from the IF signal. The developed RF front - end has the C/N0 performance over 40dB - Hz for the - 130dBm input signal power and includes the automatic gain control circuits to provide the dynamic range over 40dB.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.172-172
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• 2011

Anaerobic digestion(AD) has successfully been used for many applications that have conclusively demonstrated its ability to recycle biogenic wastes. AD has been successfully applied in industrial waste water treatment, stabilsation of sewage sludge, landfill management and recycling of biowaste and agricultural wastes as manure, energy crops. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is primarily composed of methane(CH4) and carbon dioxide(CO2) with smaller amounts of hydrogen sulfide(H2S) and ammonia(NH3), trace gases such as hydrogen(H2), nitrogen(N2), carbon monoxide(CO), oxygen(O2) and contain dust particles and siloxanes. The production and utilisation of biogas has several environmental advantages such as i)a renewable energy source, ii)reduction the release of methane to the atomsphere, iii)use as a substitute for fossil fuels. In utilisation of biogas, most of biogas produced from small scale plant e.g. farm-scale AD plant are used to provide as energy source for cooking and lighting, in most of the industrialised countries for energy recovery, environmental and safety reasons are used in combined heat and power(CHP) engines or as a supplement to natural. In particular, biogas to use as vehicle fuel or for grid injection there different biogas treatment steps are necessary, it is important to have a high energy content in biogas with biogas purification and upgrading. The energy content of biogas is in direct proportion to the methane content and by removing trace gases and carbon dioxide in the purification and upgrading process the energy content of biogas in increased. The process of purification and upgrading biogas generates new possibilities for its use since it can then replace natural gas, which is used extensively in many countries, However, those technologies add to the costs of biogas production. It is important to have an optimized purification and upgrading process in terms of low energy consumption and high efficiency giving high methane content in the upgraded gas. A number of technologies for purification and upgrading of biogas have been developed to use as a vehicle fuel or grid injection during the passed twenty years, and several technologies exist today and they are continually being improved. The biomethane which is produced from the purification and the upgrading process of biogas has gained increased attention due to rising oil and natural gas prices and increasing targets for renewable fuel quotes in many countries. New plants are continually being built and the number of biomethane plants was around 100 in 2009.

• The Journal of Pediatrics of Korean Medicine
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• v.30 no.4
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• pp.29-59
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• 2016

Objectives PRAL (Prunus armeniaca Linne Var) has been known to suppress allergic reaction. However, the cellular target and its mechanism of action were unclear. This study was designed to investigate the effect of PRAL on RBL-2H3 mast cell, which is PMA-Ionomycin-induced activated in vitro and the effect of PRAL on the MNC/Nga mice that are DNCB-induced activated in vivo. Methods In this study, IL-4, IL-13 production were examined by ELISA analysis; IL-4, IL-13, IL-31, IL-31Ra, $TNF-{\alpha}$ and GM-CSF mRNA expression were examined by Real-time PCR; manifestations of AP-1 and MAPKs transcription factors were examined by western blotting in vitro. Then skin rashes have been evaluated and verified the distribution of mast cells by H&E and toluidine blue. Also, WBC, eosinophil and neutrophil, IgE level in serum, $IFN-{\gamma}$, IL-4, IL-5 in the splenocyte culture supernatant, the absolute cell numbers of $CD4^+$, $CD8^+$, $Gr-1^+CD11b^+$, $B220^+CD23^+$, $CD3^+CD69^+$ in the Axillary Lymph Node (ALN), PBMCs and dorsal skin and IL-5, IL-13, IL-31, IL-31Ra in the dorsal skin by Real-time PCR were all evaluated from the NC/BNga mice. Results As a result of this study, the mRNA expression of IL-4, IL-13, IL-31, IL-31Ra and $TNF-{\alpha}$ and IL-4, IL-13 production, shown in ELISA analysis, were suppressed by PRAL. Results from the western blot analysis showed decrease on the expression of mast-cell-specific transcription factors, including AP-1 and p-JNK, p-ERK. Histological examination showed that infiltration levels of immune cells in the skin of the AD-induced NC/Nga mice were improved by PRAL orally adminstration. Orally- administered PRAL group also showred decreased level of IgE in the serum. This group has shown decreased the level of IL-4, IL-5, but shown elevated $IFN-{\gamma}$ level in the splenocyte culture supernatant. The same group also has shown decreased cell numbers of $CD4^+$, $CD8^+$, $CD3^+CD69^+$ in the ALN, and $CD4^+$, $Gr-1^+CD11b^+$ in the dorsal skin. PRAL oral adminstration increased cell numbers of $CD4^+$, but decreased cell numbers of $CD8^+$, $Gr-1^+CD11b^+$, $B220^+CD23^+$ in the PBMCs. Conclusions Obtained results suggest that PRAL can regulate molecular mediators and immune cells that are functionally associated with atopic dermatitis (AD) induced in the NC/Nga mice. This may play an important role in recovering AD symptoms and suppressing pruritus.

• Animal Bioscience
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• v.35 no.4
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• pp.567-576
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• 2022

Objective: An experiment was conducted to determine the effect of algae-based antioxidant containing Se yeast (EconomasE^®) on the growth performance, visceral organ weight, meat quality, and oxidative stability of broiler chickens. Methods: Nine hundred sixty, day-old male broiler chickens (Cobb, 43.97±0.55 g) were divided into three dietary treatments and allocated into 12 deep litter pens in a completely randomized design giving 4 replicate cages for each treatment. Three dietary treatments were: i) control (CON, basal diet with sufficient nutrient), ii) vitamin E (VitE, basal diet supplemented with 100 IU VitE), and iii) Algae-based antioxidant containing Se yeast (EcoE, basal diet supplemented with 0.2% algae-based antioxidant containing Se yeast: EconomasE^®). Maize soybean meal based basal diets were formulated to meet or exceed the nutrition requirement for broiler chickens. Chickens were fed ad-libitum experimental diets during the 42 days experiment period. On days 21 and 42, body weight and feed intake were measured to calculate the feed conversion ratio of the chickens. Intestine and visceral organs were measured together with meat quality and oxidative stability on days 14 and 42. Results: Chickens fed with EcoE showed improved (p<0.05) growth performance, meat quality, and higher (p<0.05) oxidative stability compared to the chicken fed on CON. Moreover, broiler chickens fed with EcoE showed similar (p<0.05) growth performance with better (p<0.05) meat quality and higher oxidative stability compared to the broiler chickens fed VitE (p<0.05). Conclusion: The algae-based antioxidant containing Se yeast can be supplemented into commercial broiler diets as a substitution of VitE while maintaining growth performance with enhancing meat quality and oxidative stability of the broiler chickens.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.557-565
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• 2021

Interest in research on various medicinal plants has increased globally over the last few decades, possibly due to their possible antibacterial and antioxidant activities. The present study was conducted to verify the antioxidant effects, antibacterial activity, and collagen synthesis and cell viability outcomes of adipocytes upon exposure to Abeliophyllum distichum Nakai (AdN). Antibacterial activity was measured through the Disc diffusion method to compare the growth ability of pathogenic microorganisms (E.coli, Salmonella). The absorbance was measured at 560 nm to calculate the active oxygen scavenging ability. Fibroblasts were dispensed in a 96-well plate at a density of 1 × 10⁵ cells·well^-1. The amount of procollagen was measured in each case using a procollagen type 1 C-peptide EIA KIT. The cytotoxicity of the Abeliophyllum distichum Nakai extract against animal adipocytes (Hanwoo backfat cells) was determined using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, a method that measures the conversion of MTS to Formazan by means of mitochondrial dehydrogenases. The concentrations of the samples were made to be 0.0125, 0025, 0.05, 0.1, and 0.5% and all were -completely absorbed into the disc in an incubator at 37℃ for 24 to 36 hours. For the 0.125 mg·disc^-1, effects of Abeliophyllum distichum Nakai on the antioxidant effect, antibacterial activity, and cell viability of adipocytes were found. However, Abeliophyllum distichum Nakai had no effect on collagen synthesis, thus suggesting that AdN extracts may be useful for the prevention and/or treatment of obesity.