• Journal of Nutrition and Health
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• v.51 no.5
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• pp.379-385
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• 2018

Purpose: Zinc (Zn) is an essential trace element for bone mineralization and osteoblast function. We examined the effects of Zn deficiency on osteoblast differentiation and mineralization in MC3T3-E1 cells. Methods: Osteoblastic MC3T3-E1 cells were cultured at concentration of 1 to $15{\mu}M$ $ZnCl_2$ (Zn- or Zn+) for 5, 15 and 25 days up to the calcification period. Extracellular matrix mineralization was detected by staining Ca and P deposits using Alizarin Red and von Kossa stain respectively, and alkaline phosphatase (ALP) activity was detected by ALP staining and colorimetric method. Results: Extracellular matrix mineralization was decreased in Zn deficiency over 5, 15, and 25 days. Similarly, staining of ALP activity as the sign of an osteoblast differentiation, was also decreased by Zn deficiency over the same period. Interestingly, the gene expression of bone-related markers (ALP, PTHR; parathyroid hormone receptor, OPN; osteopontin, OC; osteocalcin and COLI; collagen type I), and bone-specific transcription factor Runx2 were downregulated by Zn deficiency for 5 or 15 days, however, this was restored at 25 days. Conclusion: Our data suggests that Zn deficiency inhibits osteoblast differentiation by retarding bone marker gene expression and also inhibits bone mineralization by decreasing Ca/P deposition as well as ALP activity.

• Proceedings of the Korea Society of Poultry Science Conference
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• 1999.11a
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• pp.34-50
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• 1999

A cDNA encoding chicken interferon-gamma (chIFN-${\gamma}$) was amplified from P34, a CD4$^{+}$ T-cell hybridoma by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into pUC18. THe sequences of cloned PCR products were determined to confirm the correct cloning. Using this cDNA as probe, chicken genomic library from White Leghorn spleen was screened. Phage clones harboring chicken interferon-gamma (chIFN-${\gamma}$) were isolated and their genomic structure elucidated. The chIFN-${\gamma}$ contains 4 exons and 3 introns spanning over 14 kb, and follows the GT/AG rule for correct splicing at the exon/intron boundaries. The four exons encode 41, 26, 57 and 40 amino acids, respectively, suggesting that the overall structure of IFN-${\gamma}$ is evolutionairly conserved in mammalian and avian species. The 5’-untranslated region and signal sequences are located in exon 1. Several AT-rich sequences located in the fourth exon may indicate a role in mRNA turnover. The 5’-flanking region contains sequences homologous to the potential binding sites for the mammalian transcription factors, activator protein-1(AP-1) activator protein-2(AP-2) cAMP-response element binding protein(CREB), activating transcription factor(ATF), GATA-binding fator(GATA), upstream stimulating factor(USF), This suggests that the mechanisms underlying transcriptional regulation of chicken and mammalian IFN-${\gamma}$ genes may be similar.r.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.28-33
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• 2002

The LHCP circularly polarized antenna operating at DBS band is developed by employing the sequential-rotation technique in which each subarray is comprised the three truncated-corner patch square element. Antenna designed with sequentially-related technique whose M=3, p=2 has the effect of improved axial-ratio bandwidth, cross-polarization etc. And it is proved that the degradation of radiation pattern can be reduced significantly by minimizing the radiation loss of feeding line structure. Antenna designed shows extremely low side lobe level of below - 25 dB in the diagonal plane and cross-polarization level of below -20 dB in the all plane. And these performances comply with the array antenna specification for DBS.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.401-404
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• 2010

In multibit Sigma-Delta Modulator, DWA(Data Weighted Averaging) among the DEM(Dynamic Element Matching) techniques was widely used to get rid of non-linearity that caused by mismatching of unit capacitor in feedback DAC path. this paper proposed the improved DWA architecture by adjusting clock timing of the existing DWA architecture. 2n Register block used for output was replaced with 2n S-R latch block. As a result of this, MOS Tr. can be reduced and extra clock can also be removed. Moreover, two n-bit Register block used to delay n-bit data code is decreased to one n-bit Register. In order to confirm characteristics, DWA for the 3-bit output with the proposed DWA architecture was designed on 0.18um process under 1.8V supply. Compared with the existing architecture. It was able to reduce the number of 222 MOS Tr.

• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.109-114
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• 2000

The relation between the phase-shift profile fur the intermediate frequencies and the Langmuir adsorption isotherm at the poly-Ir/0.1 M $H_2SO_4$ aqueous electrolyte interface has been studied using ac impedance measurements, i.e., the phase-shift methods. The simplified interfacial equivalent circuit consists of the serial connection of the electrolyte resistance $(R_s)$, the faradaic resistance $(R_F)$, and the equivalent circuit element $(C_P)$ of the adsorption pseudoca-pacitance $(C_\phi)$. The comparison of the change rates of the $\Delta(-\phi)/{\Delta}E\;and\;\Delta{\theta}/{\Delta}E$ are represented. The delayed phase shift $(\phi)$ depends on both the cathode potential (E) and frequency (f), and is given by $\phi=tan^{-1}[1/2{\pi}f(R_s+R_F)C_P]$. The phase-shift profile $(-\phi\;vs.\;E)$ for the intermediate frequency (ca. 1 Hz) can be used as an experimental method to determine the Langmuir adsorption isotherm $(\theta\;vs.\;E)$. The equilibrium constant (K) for H adsorption and the standard free energy $({\Delta}G_{ads})$ of H adsorption at the poly-Ir/0.1 M $H_2SO_4$ electrolyte interface are $2.0\times10^{-4}$ and 21.1kJ/mol, respectively. The H adsorption is attributed to the over-potentially deposited hydrogen (OPD H).

• Bulletin of the Society of Naval Architects of Korea
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• v.18 no.2
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• pp.1-6
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• 1981

The buckling of stiffened plates is considered using a finite element method. In this paper stiffened plates are treated as orthotropic plates and by appling Mindlin's plate theory the effects of shear deformation to buckling loads are considered. In general, it is found that for moderately thick plates Mindlin's plate theory gives lower buckling load than those obtained using classical thin plate theory.

• Coupled systems mechanics
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• v.2 no.4
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• pp.375-387
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• 2013

Soils consist of an assemblage of particles with different sizes and shapes which form a skeleton whose voids are filled with water and air. Hence, soil behaviour must be analyzed by incorporating the effects of the transient flow of the pore-fluid through the voids, and therefore requires a two-phase continuum formulation for saturated porous media. The present paper presents briefly the Biot's basic theory of dynamics of saturated porous media with u-P formulation to determine the responses of pore fluid and soil skeleton during cyclic loading. Kelvin elements are attached to transmitting boundary. The Pastor-Zienkiewicz-Chan model has been used to describe the inelastic behavior of soils under isotropic cyclic loadings. Newmark-Beta method is employed to discretize the time domain. The response of fluid-saturated porous media which are subjected to time dependent loads has been simulated numerically to predict the liquefaction potential of a semi-infinite saturated sandy layer using finite-infinite elements. A settlement of 17.1 cm is observed at top surface. It is also noticed that liquefaction occurs at shallow depth. The mathematical advantage of the coupled finite element analysis is that the excess pore pressure and displacement can be evaluated simultaneously without using any empirical relationship.

• Composites Research
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• v.28 no.1
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• pp.6-14
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• 2015

Polymerization shrinkage stress analysis of dimethacrylate-based composite (Clearfil AP-X, Kuraray) and silorane-based composite (Filtek P90, 3M ESPE) used for dental composite restorations was performed using strain-gage measurement and FEM analysis. A theoretical equation based on Young's modulus and polymerization shrinkage of the composite resin was proposed to predict the polymerization shrinkage stress. Experimental results showed that the maximum shrinkage stress of Clearfil AP-X was about 2.8 times higher than Filtek P90. FEM analysis agreed with such experimental stress behaviours and showed that the maximum Von-Mises stress appeared near the margin of the filled resin adhered with PMMA ring. The stress concentration at the interface on the specimen surface was higher than that in the interior. The maximum error of shrinkage stress by the theoretical equation was reasonable within 5% in comparison to FEM results under plane stress.

• Current Optics and Photonics
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• v.1 no.2
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• pp.143-149
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• 2017

LED arrays with pixel numbers of $3{\times}3$, $4{\times}4$, and $5{\times}5$ have been studied in this paper in order to enhance the optical output power and decrease heat dissipation of an AlGaInP-based light emitting diode display device (pixel size of $280{\times}280{\mu}m$) fabricated by micro-opto-electro-mechanical systems. Simulation results showed that the thermal resistances of the $3{\times}3$, $4{\times}4$, $5{\times}5$ arrays were $52^{\circ}C/W$, $69.7^{\circ}C/W$, and $84.3^{\circ}C/W$. The junction temperature was calculated by the peak wavelength shift method, which showed that the maximum value appears at the center pixel due to thermal crosstalk from neighboring pixels. The central temperature would be minimized with $40{\mu}m$ pixel pitch and $150{\mu}m$ substrate thickness as calculated by thermal modeling using finite element analysis. The modeling can be used to optimize parameters of highly integrated AlGaInP-based LED arrays fabricated by micro-opto-electro-mechanical systems technology.

• Journal of Periodontal and Implant Science
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• v.52 no.1
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• pp.54-64
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• 2022

Purpose: This in vitro study was conducted to evaluate the effects of different debridement techniques and conditioning procedures on root surface morphology and blood clot stabilization. Methods: Two debridement techniques (curette [CU] vs. high-speed ultrasound [US]) and 2 conditioning procedures (ethylenediaminetetraacetic acid [EDTA] and phosphoric acid [PA]) were used for the study. Seven experimental groups were tested on root surfaces: 1) no treatment (C); 2) CU; 3) US; 4) CU+EDTA; 5) US+EDTA; 6) CU+PA; and 7) US+PA. Three specimens per group were observed under scanning electron microscopy (SEM) for surface characterization. Additional root slices received a blood drop, and clot formation was graded according to the blood element adhesion index by a single operator. Data were statistically analyzed, using a threshold of P<0.05 for statistical significance. Results: The C group displayed the most irregular surface among the tested groups with the complete absence of blood traces. The highest frequency of blood component adhesion was shown in the CU+EDTA group (P<0.05), while no differences were detected between the CU, US+EDTA, and CU+PA groups (P<0.05), which performed better than the US and US+PA groups (P<0.05). Conclusions: In this SEM analysis, EDTA and conventional manual scaling were the most efficient procedures for enhancing smear layer removal, collagen fiber exposure, and clot stabilization on the root surface. This technique is imperative in periodontal healing and regenerative procedures.