• Electronics and Telecommunications Trends
• /
• v.15 no.5 s.65
• /
• pp.73-85
• /
• 2000

인터넷 이용자와 트래픽의 급속한 증가는 인터넷의 이용에 많은 문제점들을 야기하고 있다. 각국은 차세대 인터넷에서의 기술 주도권 확보를 통하여 국가경쟁력을 강화하고 자국민의 삶의 질을 향상하고자 노력하고 있다. 미국의 NGI, Internet2, 캐나다의 CA*net이 대표적인 사례이다. 따라서 본 논문은 캐나다 정부가 주도적으로 전국 규모로 광 인터넷 네트워크 구축을 추진중에 있는 CA*net3에 대하여 추진 배경, 구축 및 운영 현황과 앞으로의 전개 방향을 살펴본다. 특히 CA*net3는 DWDM 기반의 코아 백본 네트워크와 CWDM과 기가 이더넷 기술에 기반을 두고 구축하고 있는 지역 네트워크(ORAN)로 이루어져 있다. 따라서 현재 추진중인 CA*net3 네트워크 구조에 대하여 중점적으로 살펴보며, 'Customer Empowered Networking Revolution'이라는 개념을 바탕으로 향후 추진하고자 하는 CA*net4 추진 동향에 대하여 자세히 살펴보고자 한다.

• The Korean Journal of Physiology and Pharmacology
• /
• v.15 no.3
• /
• pp.179-187
• /
• 2011

Regulation of B cell receptor (BCR)-induced $Ca^{2+}$ signaling by CD40 co-stimulation was compared in long-term BCR-stimulated immature (WEHI-231) and mature (Bal-17) B cells. In response to long-term pre-stimulation of immature WEHI-231 cells to ${\alpha}$-IgM antibody (0.5~48 hr), the initial transient decrease in BCR-induced $[Ca^{2+}]_i$ was followed by spontaneous recovery to control level within 24 hr. The recovery of $Ca^{2+}$ signaling in WEHI-231 cells was not due to restoration of internalized receptor but instead to an increase in the levels of $PLC{\gamma}2$ and $IP_3R-3$. CD40 co-stimulation of WEHI-231 cells prevented BCR-induced cell cycle arrest and apoptosis, and it strongly inhibited the recovery of BCR-induced $Ca^{2+}$ signaling. CD40 co-stimulation also enhanced BCR internalization and reduced expression of $PLC{\gamma}2$ and $IP_3R-3$. Pre-treatment of WEHI-231 cells with the antioxidant N-acetyl-L-cysteine (NAC) strongly inhibited CD40-mediated prevention of the recovery of $Ca^{2+}$ signaling. In contrast to immature WEHI-231 cells, identical long-term ${\alpha}$-IgM pre-stimulation of mature Bal-17 cells abolished the increase in BCR-induced $[Ca^{2+}]_i$, regardless of CD40 co-stimulation. These results suggest that CD40-mediated signaling prevents antigen-induced cell cycle arrest and apoptosis of immature B cells through inhibition of sustained BCR-induced $Ca^{2+}$ signaling.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.17 no.6
• /
• pp.245-250
• /
• 2007

This study was focused on the effect of sintering additive and particle size on the low temperature sintering of $0.85CaWO_4-0.15SmNbO_4$ ceramics. With an increase of $CaV_2O_6$ content, the sintering temperature of the specimens was reduced from $1150^{\circ}C\;to\;800^{\circ}C$. The dielectric constant (K) and Qf value were increased with $CaV_2O_6$ content. These results are due to the enhancement of the density by the liquid phase sintering. Temperature coefficient of resonant frequency (TCF) was slightly shifted to the positive value with $CaV_2O_6$ content. Typically, K of 12.64, Qf of 23,106 GHz, TCF of $-34ppm/^{\circ}C$ were obtained for the specimens with 7 wt.% $CaV_2O_6$ sintered at $900^{\circ}C$ for 3 h.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.04b
• /
• pp.88-91
• /
• 2000

The $(Sr_{0.85}Ca_{0.15})TiO_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/$SiO_2$/Si) using RF sputtering method. The crystallinity of SCT thin films is increased with increase of substrate temperature in the temperature range of 200~500$[^{\circ}C]$. V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature. The conduction mechanism of the SCT thin films observed in the temperature range of 25~100$[^{\circ}C]$ can be divided into four characteristic regions with different mechanism by the increasing current.

• Corrosion Science and Technology
• /
• v.15 no.3
• /
• pp.120-124
• /
• 2016

The effect of alloying element Ca (0, 1, and 2 wt%) on corrosion resistance and bioactivity of the as-received and anodized surface of rolled plate AM60 alloys was investigated. A plasma electrolytic oxidation (PEO) was carried out to form anodic oxide film in $0.5mol\;dm^{-3}\;Na_3PO_4$ solution. The corrosion behavior was studied by polarization measurements while the in vitro bioactivity was tested by soaking the specimens in Simulated Body Fluid (1.5xSBF). Optical micrograph and elemental analysis of the substrate surfaces indicated that the number of intermetallic particles increased with Ca content in the alloys owing to the formation of a new phase $Al_2Ca$. The corrosion resistance of AM60 specimens improved only slightly by alloying with 2 wt% Ca which was attributed to the reticular distribution of $Al_2Ca$ phase existed in the alloy that might became barrier for corrosion propagation across grain boundaries. Corrosion resistance of the three alloys was significantly improved by coating the substrates with anodic oxide film formed by PEO. The film mainly composed of magnesium phosphate with thickness in the range $30-40{\mu}m$. The heat resistant phase of $Al_2Ca$ was believed to retard the plasma discharge during anodization and, hence, decreased the film thickness of Ca-containing alloys. The highest apatite forming ability in 1.5xSBF was observed for AM60-1Ca specimens (both substrate and anodized) that exhibited more degradation than the other two alloys as indicated by surface observation. The increase of surface roughness and the degree of supersaturation of 1.5xSBF due to dissolution of Mg ions from the substrate surface or the release of film compounds from the anodized surface are important factors to enhance deposition of Ca-P compound on the specimen surfaces.

• Journal of Nutrition and Health
• /
• v.28 no.5
• /
• pp.415-425
• /
• 1995

This study was performed to investigate the effect of dietary protein level on the metabolic changes of Ca and skeletons in postmenopausal women, using ovariecotomized rats as an animal model. The female rats of 200∼250g were fed either 8%(L) or 50%(H) casein diet for 15 weeks(1st experiment). At 15th week, the rats of each diet group were undergone ovariectomy or sham-operation and they were continued to feed the same experimantal diet for 9 more months(2nd experiment). Ca metabolism, kidney function and bone composition were determined at the end of 1st experiment, 3rd and 9th month of 2nd experiment. After 1st experiment, high protein group showed higher urinary Ca and protein excretion, however, there was no difference in GFR and urinary hydroxyproline excretion. The weights, ash and Ca content of femur, scapular and vertebra tended to be higher in high protein groups which tells that high protein promoted skeletal growth. In 2nd experiment, high protein group showed higher urinary Ca and protein excretion and lower Ca absorption and balance. GFR was not affected by dietary protein and ovariectomy but increased with time, as well as kidney weight which shows the continuous development of kidney at this age of 15 month in rats. There were no difference in urinary hydroxyproline, serum ALP, and PTH among experimental groups. The weights of femur, scapular, 4th vertebra increased with time, showing the skeleton continues to grow at this age in rats. However, Ca contents, Ca/wt, Ca/ash were decreased with time and tended to be lower in high protein group especially in femur. In conclusion, prolonged feeding of high protein diet deteriorated Ca metabolism and induced bone loss as time after menopause is extended.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.19
• /
• pp.8409-8411
• /
• 2014

Purpose: To assess the value of multi-tumor marker protein chips in the diagnosis and treatment of ovarian cancer. Materials and Methods: Twelve tumor markers (CA19-9, NSE, CEA, CA242, CK19, ${\beta}$-HCG, AFP, SCC, c-PSA, CA125, CA724 and CA15-3) were detected by protein biochip in 220 patients with ovarian carcinomas, 205 with benign ovarian tumors and 200 healthy subjects. Results: The positivity rate was obviously higher in ovarian cancer (77.7%), than that in the benign cases (26.3%, p<0.01) and healthy subjects (4.5%, p<0.01). Serum levels of tumor markers were furthermore significantly higher in cases with lymph node metastasis (86.8%) than those without metastasis (44.7%), p<0.01. Conclusions: Multi-tumor marker protein chips provide important assistance in the diagnosis and treatment evaluation in ovarian cancers.

• Transactions of Materials Processing
• /
• v.15 no.8 s.89
• /
• pp.615-620
• /
• 2006

The reduction behavior of $TiO_{2}$ in Al and Al/CaSi containing self-reducing $TiO_{2}$ briquettes(SRTB) was investigated. The maximum yield of Ti was expected with the slag composition of 45-55%CaO in the $CaO-Al_{2}O_{3}$ system. When $CaCO_{3}$ was used as a flux, the oxidation loss of reducing agent by $CO_{2}$ should be compensated, and therefore it leads to excessive requirement of the reducing agent. By using Al and CaSi mixture as a reducing agent of $TiO_{2}$, the reaction products both oxide and metal could be liquefied, and separated effectively with each other. As a result, the yield of Ti increases remarkably. The optimum mixing ratio of CaSi to Al is 78%CaSi-22%Al.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.12
• /
• pp.4933-4938
• /
• 2014

Background: Although various tumor markers have been utilized in management of stomach cancer (SC), only a few reports have described relevance of examples such as CYFRA 21-1 and neuron-specific enolase (NSE). The purpose of this study was to evaluate the potential diagnostic performance of carcinoembryonic antigen (CEA), CA 19-9, CA72-4, CYFRA 21-1 and NSE in patients with SC. Materials and Methods: Ninety-six SC patients with pathologic confirmation between 2012 and 2013 were enrolled. Serum levels of five tumor markers were analyzed using a solid-phase immunoradiometric assay. Receiver operating characteristic (ROC) curves were plotted for the five tumor markers to investigate their diagnostic powers and adjusted cutoff values derived from analysis of ROC curves were evaluated to calculate the sensitivity of each for SC with recommended cutoff values. Results: Based on two different cutoff values (recommended and adjusted), CYFRA 21-1 (${\geq}2.0$ and 1.2 ng/ml) had a respective sensitivity of 50% and 78.1%, compared with 8.3% and 18.8% for CEA (${\geq}7.0$ and 3.9 ng/ml), 15.6% and 18.8% for CA 19-9 (${\geq}37$ and 26.7 ng/ml), 28.1% and 9.6% for CA 72-4 (${\geq}4.0$ and 13 ng/ml) and 7.3% and 7.3% for NSE (${\geq}14.7$ and 15.0 ng/ml) in the initial staging of primary SC. The area under the curve (AUC) for CYFRA 21-1, with a value of 0.978 (95% confidence interval, 0.964-0.991) was comparatively the highest. Univariate analysis revealed significant relationships between tumor marker level and lymph node involvement, metastasis and staging with CYFRA 21-1, CA 72-4 and NSE. Conclusions: CYFRA 21-1 was the most sensitive tumor marker and showed the most powerful diagnostic performance among the five SC tumor markers. NSE and CA 72-4 are significantly related to lymph node involvement, metastasis or stage. Further evaluations are warranted to clarify the clinical usefulness and prognostic prediction of these markers in SC.

• Korean Journal of Materials Research
• /
• v.17 no.8
• /
• pp.414-419
• /
• 2007

We report the electrical conductivity of the mixed alkali silicate glasses in the system (60-x)$SiO_2-40Na_2O-xCaO(x=0\sim15wt%)$ in the temperature range from $150^{\circ}C$ to $620^{\circ}C$. In the range from $150^{\circ}C$ to glass transition temperature$(T_g)$, the electrical conductivities of glass samples had a tendency to be proportion with temperature. The glasses of containing over 7.5wt% CaO showed lower conductivities than the glasses of containing 0 and 5wt% CaO because two kinds of alkali ions$(Na^+,\;Ca^{2+})$ were obstructed each other. On the other hand, in the range from $T_g$ to $620^{\circ}C$, the electrical conductivity of glasses($7.5{\leq}x{\leq}12.5$) was unstable and decreased in some region. From XRD results, the $Na_4Ca(SiO_3)_3$ phase were observed in these glasses. This means the alkali ions didn't behave as carrier, it seems that this caused the conductivities decrease. In case of glass of containing 15wt% CaO, any crystal phase were not observed. This means the alkali ions behaved as carrier, it consequently seems the conductivity increased.