• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.6C
• /
• pp.502-511
• /
• 2012

As the importance of GNSS system increases, the necessity of independent system is increased also. When the independent GNSS system is required, GNSS signal design is necessary with requirement definition. This paper suggests the design method of GNSS signal using the analysis result of receiver performance. First, the candidates are defined based on the design elements. Then the receiver performance of the candidates is analyzed based on the performance evaluation parameters. The weights of performance evaluation parameter are defined in order to consider the receiver performance in a various aspects. Finally, the calculation of normalized performance evaluation parameters and weights are derived to obtain the compared value for signal selection. Spreading code, modulation method and carrier frequency are considered as design parameters. Also, correlation width, DLL PLL thermal noise jitter, frequency bandwidth and side lobe peak ratio are considered as performance evaluation parameters. And positioning performance, robustness to noise, bandwidth efficiency are considered as the performance aspects. This paper analyzes the performance of each candidate using software based simulator and suggest the method to compare objectively the performance of each candidates.

• Korean Journal of Optics and Photonics
• /
• v.29 no.4
• /
• pp.166-172
• /
• 2018

In this paper, we propose a new method to predict a mirror's surface deformation due to the stress of moisture release by a coating in the environment of outer space. We measured the surface deformation of circular samples 50 mm in diameter and 1.03 mm thick, using an interferometer. The results were analyzed using Zernike fringe polynomials. The coating stress caused by moisture release was calculated to be 152.7 MPa. This value was applied to an analytic model of a 1.25 mm thickness sample mirror, confirming that the change of surface deformation could be predicted within the standard deviation of the measurement result ($78.9{\pm}5.9nm$). Using this methodology, we predicted the surface deformation of 600 mm hyperbolic mirror for the Compact Advanced Satellite, which will be launched in 2019. The result is only $2.005{\mu}m$ of focal shift, leading to 2.3% degradation of modulation transfer function (MTF) at the Nyquist frequency, which satisfies the requirement.

• Food Science and Preservation
• /
• v.19 no.3
• /
• pp.455-461
• /
• 2012

Obesity, a strong risk factor for the development of chronic diseases, is characterized by an increase in the number and size of adipocytes differentiated from precursor cells, preadipocytes. Recent research suggests that increased reactive oxygen species (ROS) production in 3T3-L1 adipocyte facilitates adipocyte differentiation and fat accumulation. This study was to investigate whether reduced ROS production by Sargassum micracanthum extract (SME) could protect the development of obesity through inhibition of adipogenesis. 3T3-L1 preadipocytes were treated SME for up to 8 days following standard induction of differentiation. The extent of differentiation reflected by amount of lipid accumulation and ROS production was determined by Oil red O staining and nitroblue tetrazolium (NBT) assay. Treatment of SME significantly inhibited ROS production and adipocyte differentiation that is depend on down regulation of NADPH oxidase 4 (NOX4), a major ROS generator, and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein alpha ($C/EBP{\alpha}$), a key adipogenic transcription factor. These results indicate that SME can inhibit adipogenesis through a reduced ROS level that involves down-regulation of NOX4 expression or via modulation of adipogenic transcription factor.

• Archives of Pharmacal Research
• /
• v.28 no.8
• /
• pp.948-955
• /
• 2005

Glomerular mesangial cells (GMCs) in diverse renal diseases undergo cell proliferation and/or hypertrophy, and gangliosides have been reported to play an important role in modulating cell structure and function. This study compared the effects of transforming growth $factor-\beta\; (TGF­\beta1)$ and the effects of the application of exogenous gangliosides on GMCs and investigated whether the application of exogenous gangliosides regulated cellular proliferation and hypertrophy. Human GMCs were cultured with exogenous gangliosides and $TGF-\beta1$ in a media containing $10\%$ fetal bovine serum and in a media without the fetal bovine serum. Exogenous gangliosides biphasically changed the proliferation of human GMCs (0.1-1.0 mg/mL). A low concentration (0.1 mg/mL) of gangliosides mainly increased the number of human GMCs, whereas cellular proliferation was significantly reduced by raising the concentration of exogenous gangliosides. $TGF-\beta1$ greatly reduced the number of human GMCs in a concentration­dependent manner (1-10 ng/mL). Serum deprivation accelerated the gangliosides- and $TGF­\beta1-induced$ inhibition of mesangial cell proliferation to a greater extent. Gangliosides (1.0 mg/ mL) and $TGF-\beta1$ (10 ng/mL) both caused a significant increase in the incorporation of $[^3H]leucine$ per cell in the serum-deprived condition, whereas it was completely reversed in serum­supplemented condition. Similar results to the $[^3H]leucine$ incorporation were also observed in the changes in cell size measured by flow cytometric analysis. These results show that exogenous gangliosides modulate cell proliferation and hypertrophy in cultured human GMCs, and these cellular responses were regulated differently based on whether the media contained serum or not. Results from the present study raise new possibilities about the potential involvement of gangliosides in the development of mesangial cell proliferation and hypertrophy.

• Archives of Pharmacal Research
• /
• v.29 no.8
• /
• pp.633-644
• /
• 2006

In last couple of decades the use of natural compounds like flavonoids as chemopreventive agents has gained much attention. Our current study focuses on identifying chemopreventive flavonoids and their mechanism of action on human prostate cancer cells. Human prostate cancer cells (PC3), stably transfected with activator protein 1 (AP-1) luciferase reporter gene were treated with four main classes of flavonoids namely flavonols, flavones, flavonones, and isoflavones. The maximum AP-1 luciferase induction of about 3 fold over control was observed with $20\;{\mu}M$ concentrations of quercetin, chrysin and genistein and $50\;{\mu}M$ concentration of kaempferol. At higher concentrations, most of the flavonoids demonstrated inhibition of AP-1 activity. The MTS assay for cell viability at 24 h showed that even at a very high concentration $(500\;{\mu}M)$, cell death was minimal for most of the flavonoids. To determine the role of MAPK pathway in the induction of AP-1 by flavonoids, Western blot of phospho MAPK proteins was performed. Four out of the eight flavonoids namely kaempferol, apigenin, genistein and naringenin were used for the Western Blot analysis. Induction of phospho-JNK and phospho-ERK activity was observed after two hour incubation of PC3-AP1 cells with flavonoids. However no induction of phospho-p38 activity was observed. Furthermore, pretreating the cells with specific inhibitors of JNK reduced the AP-1 luciferase activity that was induced by genistein while pretreatment with MEK inhibitor reduced the AP-1 luciferase activity induced by kaempferol. The pharmacological inhibitors did not affect the AP-1 luciferase activity induced by apigenin and naringenin. These results suggest the possible involvement of JNK pathway in genistein induced AP-1 activity while the ERK pathway seems to play an important role in kaempferol induced AP-1 activity.

• Korean journal of applied entomology
• /
• v.51 no.4
• /
• pp.349-356
• /
• 2012

Eicosanoid mediates various cellular immune responses in insects. This study aimed to discover its novel action on the modulation of hemocyte populations in response to an immune challenge. Upon bacterial challenge, the last instar larvae of the beet armyworm, Spodoptera exigua, increased their total hemocyte density in 2 h, and then decreased it to a basal hemocyte density level. This rapid increase in total hemocyte density was explained by an increase of plasmatocyte and spherulocyte densities. When larvae were treated with dexamethasone (a specific phospholipase $A_2$ ($PLA_2$) inhibitor), they did not show any increase in hemocyte density in response to bacterial challenge. However, the addition of arachidonic acid (a catalytic product of $PLA_2$) to larvae treated with dexamethasone recovered the up-regulation of hemocyte density in response to bacterial infection. Among eicosanoid, cyclooxygenase (COX), but not lipoxygenase (LOX), products seemed to mediate the increase of hemocyte density in response to bacterial infection because naproxene (a COX inhibitor) inhibited the hemocyte density increase, though esculetin (a LOX inhibitor) did not. Prostaglandin $E_2$, a COX product, significantly increased the hemocyte density even without bacterial infection. These results suggest that eicosaniod mediates a rapid increase in total hemocyte density in response to immune challenge.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.27 no.11
• /
• pp.119-125
• /
• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.

• Journal of Acupuncture Research
• /
• v.17 no.2
• /
• pp.231-246
• /
• 2000

Acupuncture has been used for treatment of numerous diseases, especially for pain control in the oriental culture. However, the mechanism of pain control by acupuncture was not clear so far. The present study was examined that the effects of electro-acupuncture (EA) applied to the acu-point of extra-segmental area on modulation of formalin induced pain in Sprague - Dawley rats. In order to apply EA to acu-points in the plantar area of right fore paws, a pair of teflon - coated stainless steel wires were implanted in HT 7 (shin-mun) and PC 7 (dae-neong) 5 days before behavioral test. A behavioral test was performed by means of video camera after injection of 5% formalin ($50{\mu}l$) into the lateral plantar region of left hind paw. EA was delivered by a constant current stimulator at 4~5 mA, 2 ms, and 10 Hz for 30 min. The electromyographic activities were recorded in the biceps femoris muscle under chloral hydrate anesthesia. Test stimuli with 1~9mA were applied to the sural nerve territory including the medial portion of the 4th toe and the lateral portion of the 5th toe. Behavioral responses including favoring, flinching and bitting were occured in the biphasic pattern, such as the lst phase (0~5 min) and the 2nd phase (20~45 min) after formalin injection. However, EA (4~5 mA, 2 ms, 10 Hz) significantly inhibited Che behavioral responses. EMG activities of flexor reflex had a latency of 100~300 ms and thresholds of test stimuli for EMG were 4~5 mA in normal rats. Injection of formalin decreased threshold of test stimuli and increased EMG activities for 2hrs after injection. However, EA significantly inhibited EMG activities of flexor reflex increased by formalin and recovered EMG evoked thresholds. These results suggest that contralateral extra-segmental EA inhibits the first and second phases of formalin induced pain but their mechanism be needed to examine additionally.

• Journal of Acupuncture Research
• /
• v.17 no.2
• /
• pp.153-168
• /
• 2000

Introduction : In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex and the change of c-fos in secondary neurons in the spinal cord. Materials and Methods : Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12) were measured. We used Fos immunohistochemical technique to study the neuronal activity in the spinal cord. Results : 1. Expression of c-fos in superficial dorsal horn(SDH), nucleus proprius(NP) and neck of dorsal hom(N) on 6~9th thoracic spine decreased significantly at $2.5{\times}10-4$g/kg Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 2. The numeral change of Fos-LI neurons on the NP, N, and ventral gray(V) on 6-9th thoracic spine, SDH on 9-11th thoracic spine, and SDH and V on 11~13th thoracic spine decreased significantly at Chungwan(CV12) Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 3. The correlation between the numbers of writhing refleax and Fos-LI neurons in T6-13 segment was statistically statistically significant at Chungwan(CV12) Bee Venom aqua-acupuncture. Conclusion : This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12) decreases the numbers of Fos-LI neurons. As the analgegic effects of Bee Venom aqua-acupuncture is recognized. Bee Venom aqua-acupuncture treatment is expected for pain modulation. In order to use it in many ways, more researches are needed for the dose and stability of Bee Venom aqua-acupuncture.

• The Korea Journal of Herbology
• /
• v.35 no.4
• /
• pp.17-23
• /
• 2020

Objectives : In this study, we investigated the protective effects of Charybdis japonica (C. japonica) water extract on the acute reflux esophagitis in rat models. Methods : Twenty rats were divided into four groups for examination: normal control group (n=6), the reflux esophagitis group (n=6), reflux esophagitis treated with positive control group (ranitidine 40 mg/kg, n=6), reflux esophagitis treated with C. japonica group (100 mg/kg, n=6). All rats fasted for 18 hr and then were induced with reflux esophagitis by a pylorus and forestomach ligation operation. After 4 hr, the rats were sacrificed. The proinflammatory cytokine and proteins expression measured by western bolt assay, and the histopathological analysis of the esophageal mucosa measured by hematoxylin and eosin staining. Results : C. japonica administration significantly was protecting esophageal mucosal damage upon histological analysis of reflux esophagitis in rats. The C. japonica treatment confirmed the protection of the reduction of claudin-5, an evaluation index of the damage of tight junctions in the reflux esophagitis. C. japonica was also found to inhibit the expression of proteins such as COX-2 and TNF-α in the rat esophagus. C. japonica markedly attenuated the activation of NF-κB and phosphorylation of IκBα at the same time. Conclusion : These results indicated that C. japonica suppressed the development of esophagitis through the modulation of inflammation by regulating NF-κB activation. Based on these findings, we concluded that C. japonica can prevent reflux esophagitis.