• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.67-70
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• 2002

The composites were fabricated 61vol% ${\beta}$-SiC and 39vol.% $TiB_2$ powders with the liquid forming additives of 8, 12, 16wt% $Al_2O_3+Y_2O_3$ by pressureless annealing at $1650^{\circ}C$ for 4 hours to form YAG. The result of phase analysis of composites by XRD revealed ${\alpha}$-SiC(6H), $TiB_2$, and YAG($Al_5Y_3O_{12}$) crystal phase. The relative density and the Young's modulus showed the highest value of 82.29% and 54.60 Gpa for composites added with 16wt% $Al_2O_3+Y_2O_3$ additives at room temperature.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.3
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• pp.377-381
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• 1999

Objectives: Recent studies, including our own, demonstrated that the novel expression of LH gene in rat gonads and uterus, indicating that the local production and action of the LH-like molecule. In the present study, we investigated whether human uterus also expresses the LH gene. Design: Reverse transcription-polymerase chain reaction (RT-PCR) amplified the cDNA fragments coding $LH_{\beta}$ polypeptide from human endometrium but not from myometrium. Presence of the transcripts for the ${\alpha}$-subunit in human endometrium was also confirmed by RT-PCR. Results: Transcripts for $LH_{\beta}$ subunit were detected in endometrial samples from women with endometriosis. The gene for LH/hCG receptor was expressed in both endometrium and myometrium, showing good agreement with previous studies. Increased level of $LH_{\beta}$ transcript was determined in the endometrium from follicular phase compared to that from luteal phase. Conclusion: Taken together, our findings demonstrated that 1) the genes for LH subunits and LH/hCG receptor are expressed in human uterus, 2) the uterine LH expression was changed during menstrual cycle, suggesting that the uterine LH may playa local role in the control of uterine physiology and function(s).

• Journal of Powder Materials
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• v.17 no.6
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• pp.482-488
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• 2010

In this study, $FeSi_2$ as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below $1200^{\circ}C$ for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering ($1200^{\circ}C$, 12 h). In order to precipitate ${\beta}-FeSi_2$, heat treatment was performed at $850^{\circ}C$ with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase ${\beta}-FeSi_2$ was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.

• Journal of Korea Foundry Society
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• v.35 no.3
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• pp.53-61
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• 2015

Effects of Zn addition on the microstructure and corrosion behavior of Mg-8%Al-(0-1)%Zn casting alloys were investigated. With increasing Zn content, the amount of ${\beta}(Mg_{17}Al_{12})$ phase increased, while ${\alpha}$-(Mg) dendritic cell size became reduced. The corrosion rate decreased continuously with the increase in the Zn content. The evaluation of the microstructural evolution indicates that the improved barrier effect of ${\beta}$ particles formed more continuously along the dendritic cell boundaries and the incorporation of more ZnO into the surface corrosion product, by which the absorption of $Cl^-$ ions is impeded, are responsible for the better corrosion resistance in relation to the Zn addition.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.2
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• pp.88-95
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• 2022

Titanium alloy for bio-medical applications have been developed to reduce the toxicity of alloying elements and avoid the stress-shielding effect which is caused by relatively high elastic modulus compared to bone. Ti-39Nb-6Zr (TNZ40) alloy of elastic modulus exhibits around 40 GPa in the case of beta single phase. However, the strength of this alloy is lower than the other types of titanium alloys. Many research found that adding oxygen to beta-titanium alloys is beneficial for improving the strength through solid solution strengthening. In this study, TNZ40 ingots with addition of O were prepared by an arc remelting process (Ti-39Nb-6Zr-0.16O (wt.%), Ti-39Nb-6Zr-0.26O (wt.%)). Thermo-mechanical processing (i.e., heat treatment, cold swaging and aging heat treatment) has been performed under various conditions. Therefore, the aim of this study is to investigate the effect of oxygen content and ω phase formation on microstructure and mechanical properties.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.233-237
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• 2008

The essential oil was obtained from the aerial part of Rhododendon mucronulatum Turcz. var. ciliatum Nakai by steam distillation, samples were collected by headspace (HS) and solid-phase microextraction (SPME) methods, and the compositions of the oil were analyzed by gas chromatography-mass spectrometry (GC-MS). Nineteen constituents were identified from the essential oil: 15 carbohydrates, 3 alcohols, and 1 acetates. Major constituents were 2-${\beta}$-pinene (16.1%), camphene (11.9%), ${\delta}$-3-carene (11.4%), d,l-limonene (9.5%), and ${\gamma}$-terpinene (9.5%). By SPME extraction, seventeen constituents were identified: 13 hydrocarbons, 1 alcohol, 1 nitrogen-containing compound, 1 acetate, and 1 amine. Major constituents of the SPME-extracted sample were cam phene (19.6%), 2-${\beta}$-pinene (18.0%), ${\delta}$-3-carene (17.4%), trimethyl hydrazine (9.7%), ${\gamma}$-terpinene (8.5%), and d,l-limonene (5.5%). By HS extraction, thirteen constituents were identified: 11 hydrocarbons, 1 alcohol, and 1 nitrogen-containing compound. Major constituents of the HS-extracted sample were camphene (25.8%), ${\delta}$-3-carene (24.8%), 2-${\beta}$-pinene (20.2%), d,l-limonene (5.4%), tricyclene (5.1%) and trimethyl hydrazine (4.6%). The fragrance of the essential oil was coniferous, balsamic, and woody, and the $IC_{50}$ value of the essential oil was 0.030 ${\mu}g/mg$ in MTT assay using UaCaT keratinocyte cell line.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.473-480
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• 1997

$\beta-SiC$powder with or without the addition of 1-3 wt% of $\beta-SiC$ whiskers (seeds) was hot-pressed at $1850^{\circ}C$ for 1 h using $Al_2O_3$ and $Y_2O_3$ as sintering aids. The hot-pressed materials were subsequently annealed at $1950^{\circ}C$ to enhance grain growth. The introduction of $\beta-SiC$ whiskers into $\beta-SiC$ does not affect the microstructure as well as mechanical properties significantly because the whiskers are not viable in the presence of liquid phase during hot-pressing. The strengths and fracture toughnesses of the hot-pressed and subsequently 5 h-annealed materials with 1 wt% $\beta-SiC$ whiskers and without $\beta-SiC$ whiskers were 465 MPa and 5.8 MPaㆍ$m^{1/2}$, and 451 MPa and 5.5 MPaㆍ$m^{1/2}$, respectively.

• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.611-626
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• 1998

Cytokines are intercellular peptide mediators that regulate homeostasis and host defense reactions in living body. Of the diversity of cytokines in terms of biological accomplishment, interleukin $1-{\beta}$($IL-1{\beta}$) and tumor necrosis factor(TNF) are the most conspicuous cytokines with a wide variety of effects on cells involved in inflammatory and immune responses, and likely to be involved in the inflammatory pathogenesis of oral tissue as well. The present study was designed to explicate the role of $IL-1{\beta}$ on inflammatory revelation of oral tissues in mice biochemically. In the Induced arthritis by injection of 10${\mu}g$ LPS shown the relaese of 0.93 ${\mu}g$ $IL-1{\beta}$/joint with a peak at at 4-5 h. and diminished at 24t and the release of $TNF_{\alpha}$ of 1.25 ${\mu}g$/joint with a peak at 2-3h and diminished at 6h. After injection of th $IL-1{\beta}$ into the joint, the mumber of leucocytes proliferated with a peak at 4-5h and diminished at 36h and the loss of proteoglycan showed with maximum at 15-30h. After injection of $IL-1{\beta}$ into the oral tissue, cycloosygenase metabolites ($PGE_2$) accumulated in the oral tissue with dose dependant. These elucidated $IL-1{\beta}$ to be inflammatory mediator in the early phase of its pathogenesis. Intraoral injection of recombinant $IL-1{\beta}$ induced the proliferation of leukocytes in situ. $IL-1{\beta}$ took an pertinent part in the development of inflammation and the succession of cellular infiltration. The results exemplify that $IL-1{\beta}$ plays a significant role in mediating inflammatory response induced by LPS in oral tissue, the inflammatory response is regulated by $IL-1{\beta}$ at an acute phase of pathogenesis.

• Journal of Pharmaceutical Investigation
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• v.12 no.4
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• pp.132-144
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• 1982

The inclusion of ${\beta}-cyclodextrin$ $({\beta}-CyD)$ with prothionamide in aqueous phase was investigated by circular dichroism(CD), ultraviolet (UV) absorption, and solubility technique. The results suggested that a region of drug chromophore was located within the asymmetric center of ${\beta}-cyclodextrin$. Solubility and spectral changes were quantitatively treated to obtain stoichiometric ratio, which was found to be 1 : 1, and formation constants which were determined by solubility, CD, and UV method were 257, 367, and 389 $M^{-1}$, respectively. Also, the formation constant of the inclusion complex was determined by CD method at various pH. The result was that $K_c$ depended upon the pH of medium, and this fact also supported that thioamide moiety was accomodated in the cavity of ${\beta}-cyclodextrin$.

• Analytical Science and Technology
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• v.12 no.5
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• pp.387-396
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• 1999

The retention behavior of Cot(II)-dithiocarbamate(DTC) chelates in reversed phase high performance liquid chromatography was investigated. Enthalpy and entropy of chelates transfer from the mobile phase to the stationary phase were calculated from retention data using van't Hoff plots. The dependence of In k' on enthalpy was decreased with increasing organic solvent ratio on the mobile phase. The compensation temperatures(${\beta}$) calculated from the slope of $-{\Delta}H^0$ vs In k' were in the range of 756.3-888.5 K. From these results. it was found that the retention mechanism of DTC chelates was invariant under the various temperatures and was largely affected by the solvophobie effect. Liniear relationship between S index and log k' in emprical retention equation, $log\;k^{\prime}=log\;{k_w}^{\prime}-S_{\varphi}$ showed that S index was influenced mainly by the interaction between DTC chelates and the mobile phase.