• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.7-14
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• 1999

Wekk oriented $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ suppercondcting thick films were fabricared on copper tape by LiReac-PreCu (liquid reaction between a Cu-free precousor and Cu tape) method. Cu-free precursor power which is composed of $Bi_{2}Sr_{2}Ca_{5}$ was printed on a copper tape by screen printing and was heat-treated. The speciment were partially in a molten state at the heat treatment temperature (85$0^{\circ}C$~87$0^{\circ}C$). The heat heat treatments for the reaction were performed in air or low oxygen pressure in several stages. XRD analyses of the resulting Bi2Sr2CaCu2O8 superconducting tapes show that the $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ phase is dominant and a small amount of $Bi_{2} Sr_{2} Cu_{2} O_{6}$ phase is detected. Both phases are aligned in the c-axis direction.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.689-695
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• 1991

Dielectric properties of Ba1-$\chi$Sr$\chi$Ti1-yCayO3-y ceramics, where Sr and Ca were doped to Ba-site and Ti-site within the range of 0 x 0.24 and 0 y 0.05, respectively, were investigated. The substitution of Ca for Ti, which maintained the high resistivity of these formulations after sintering in a reducing atmosphere, was confirmed. Ca addition decreased the tetragonality c/a, increased the unit cell volume, and lowered Curie temperature, which were attributed to the occupancy of Ca2+ ions on Ti-sites. The lowering of Curie temperature by Ca addition was affected by the substitution of Sr for Ba-site; within 2 mol% of Ca, Curie temperature was lowered at a rate of 2$0^{\circ}C$ and 16$^{\circ}C$ per mol% of Ca at x=0 and x=0.08, respectively. Whereas the resistivity of the formulations without Ca was reduced to 107 {{{{ OMEGA }}cm, when sintered at low oxygen partial pressure of 10-9 MPa, the resistivity value higher than 1011 {{{{ OMEGA }}cm was maintained for the formulations containing Ca more than 0.5 mol%. Dielectric loss factor, tan$\delta$, was about 1% for most formulations.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.531-536
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• 2022

Umami taste-yielding foods, such as, Joseonganjang, dried anchovies, dried shiitake, dried Konbu (kelp), and Yukjeot, are widely used in the Korean cuisine as soup base. While Umami taste enhancement related to Kokumi taste substances has been proposed in human sensory studies, the potential action of Kokumi taste substances has not been explored on calcium-sensing receptors (CaSR), here referred to as Kokumi taste receptors. In this study, we investigated the effect of Umami taste-yielding foods on Kokumi taste receptors using cells expressing human CaSR. We monitored the temporal changes in intracellular Ca²⁺ in HEK293T cells expressing CaSR in response to aqueous extract of Joseonganjang, dried anchovies, dried shiitake, dried Konbu, and Yukjeot. Kokumi substances tested-glutathione and γ-Glu-Val-Gly- evoked intracellular Ca²⁺ influx in a concentration-dependent manner. A similar increment of intracellular Ca²⁺ influx was induced by Joseonganjang, Yukjeot, and dried anchovies, but not by dried shiitake and dried Konbu. Only Joseonganjang- and Yukjeot-evoked intracellular Ca²⁺ influx was significantly reduced by NPS 2143, a CaSR-specific antagonist. These data indicated that some Umami substances/Umami-yielding materials could activate CaSR, but this property was not observed for all the Umami tasting substances.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.223-230
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• 1999

Alterations of cardiovascular function associated with various thyroid states have been studied. In hyperthyroidism left ventricular contractility and relaxation velocity were increased, whereas these parameters were decreased in hypothyroidism. The mechanisms for these changes have been suggested to include alterations in the expression and/or activity levels of various proteins; ${\alpha}-myosin$ heavy chain, ${\beta}-myosin$ heavy chain, ${\beta}-receptors,$ the guanine nucleotide-binding regulatory protein, and the sarcolemmal $Ca^{2+}-ATPase.$ All these cellular alterations may be associated with changes in the intracellular $Ca^{2+}$ concentration. The most important regulator of intracellular $Ca^{2+}$ concentration is the sarcoplasmic reticulum (SR), which serves as a $Ca^{2+}$ sink during relaxation and as a $Ca^{2+}$ source during contraction. The $Ca^{2+}-ATPase$ and phospholamban are the most important proteins in the SR membrane for muscle relaxation. The dephosphorylated phospholamban inhibits the SR $Ca^{2+}-ATPase$ through a direct interaction, and phosphorylation of phospholamban relieves the inhibition. In the present study, quantitative changes of $Ca^{2+}-ATPase$ and phospholamban expression and the functional consequences of these changes in various thyroid states were investigated. The effects of thyroid hormones on (1) SR $Ca^{2+}$ uptake, (2) phosphorylation levels of phospholamban, (3) SR $Ca^{2+}-ATPase$ and phospholamban protein levels, (4) phospholamban mRNA levels were examined. Our findings indicate that hyperthyroidism is associated with increases in $Ca^{2+}-ATPase$ and decreases in phospholamban levels whereas opposite changes in these proteins occur in hypothyroidism.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.849-853
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• 1999

In the study, superconducting properties of $Bi_2$-x(sub)$LSr_2$Ca(sub)1+x(sub)$LCu_2$O(sub)8+d (x(sub)L=0, 0.05, 0.1, 0.2) films prepared by the LPE method was investigated. The peak decompositions of Sr3d and Ca2p XPS spectra, together with the EPMA results, elucidated the occupancies of Bi, Sr and Ca atoms on the SrO- and Ca-layers. The lattice parameter c monotonically increased with increasing x(sub)L for $0\leq$x(sub)L$\leq$0.2. The superconducting critical temperature T(sub)c showed a maximum value around x(sub)L=0.1. The x(sub)L dependence of the superconducting critical temperature T(sub)c and the lattice parameter c are explained by the changes of the excess oxygens in the BiO-layer. Since distribution and deficiency of the atoms in SrO-layer have influenced on superconducting properties and crystal structure.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.1
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• pp.1-5
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• 1997

The $Bi_2Sr_2Ca_{n-1}Cu_nOy$(BSCCO) phase is well known to be a superconductor having a strong anisotropic behavior. It can be seen that it is difficult to control the growth direction. In this study, we try to grow a Bi-Sr-Ca-Cu-O phase crystal by the crystal pulling method with a seed crystal and crucibel rotation. Relatively large crystals of the order of $5{\times}5{\times}5{\textrm}{mm}^3$ dimensions can be obtained. We also discuss the possible crystallization field of the $BiO_{1.5}$-(Sr, Ca)O-CuO ternary phase diagram, and present some results of the characterization and magnetic measurements on the grown crystal.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.125-136
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• 1994

To characterize the SR Ca-release channel protein complex of crustacean, $^{45}Ca-release,\;[^3H]ryanodine$ binding, and immunoblot studies were carried out in the crayfish and/or lobster skeletal sarcoplasmic reticulum. Bmax and affinity of crayfish SR to ryanodine were lower than those of lobster SR. AMP (5mM) increased $[^3H]ryanodine$ binding significantly in both vesicles (P<0.05). $Mg^{2+}$(5mM) or tetracaine(1mM) inhibited $[^3H]ryanodine$ binding significantly in both vesicles (P<0.001), but ruthenium red $(10\;{\mu}M)$ inhibited it moderately. In SDS polyacrylamide gel electrophoretic analysis of crayfish SR vesicles, there was a high molecular weight band that showed similar mobility with Ca-release channel protein of lobster skeletal SR, but more rapid mobility (HMWBr) than that of rabbit skeletal SR (HMWBS). Immunoblot analysis showed that polyclonal Ab to lobster skeletal SR Ca-release channel protein was react with HMWBr of crayfish skeletal SR, but not with that of HMWBs of rabbit skeletal SR. ^{45}Ca-release from crayfish skeletal SR vesicles was increased by the increase of extravesicular calcium from $1{\mu}M$ to 1mM. This Ca-release phenomenon was similar, but more sensitive in the low concentration of $Ca^{2+}$, compared to that from lobster SR vesicles. AMP (5mM) or caffeine (10mM) did not affect to $^{45}Ca-release.\;^{45}Ca-release$ was inhibited slightly ($3{\sim}8%\;by\;Mg^{2+}$) (5mM) or tetracaine (1mM), and moderately (23%) by high concentration of ruthenium red $(300\;{\mu}M)$. From the above results, it is suggested that SR Ca-release channel protein of crustacean has different properties from that of the rabbit, and similar properties between crayfish and lobster in functional and immunological aspects, but Ca-release via crayfish channel may be more sensitive to calcium.

• Proceedings of the Korean Biophysical Society Conference
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• 2002.06b
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• pp.56-56
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• 2002

Muscle contraction and relaxation are regulated by the sarcoplasmic reticulum (SR)-mediated $Ca^{2＋}$ release and $Ca^{2＋}$ uptake. The SR functions are closely related with the proteins residing in the SR such as ryanodine receptor, $Ca^{2＋}$-ATpase, calsequestrin, triadin and junctin. In an effort to further identify important functional SR proteins, experiments of sucrose-density gradient of SR fractionation, concanavalin A treatment, 2D gel electrophoresis, $^{45}$ Ca$^{2+}$ overlay, Strains-all staining, and peptide finger printing (PFP) were carried out.(omitted)d)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.8
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• pp.664-670
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• 1998

고순도의 Bi(Pb)-Sr-Ca-Gu-O 초전도 분말의 얻기 위하여 액상법의 하나인 이멀젼 건조방법이 응용되었다. 다양한 합성 변수 중 오일과 용액의 계면활설제의 혼합비율을 조정하여 고순도의 Bi(Pb)-Sr-Ca-Gu-O 초전도 분말을 성공적으로 얻을 수 있었다. 이 공정의 최적 혼합비율은 70:20:10이였다. 관측된 분말을 구형이었으며 마이크론 크기 이하의 균일한 크기를 보였다. 최적의 소결조건에 한에 $840^{\circ}C$ 50시간의 열처리를 통하여 거의 108K를 갖는 초전도 분말이 얻어졌다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.64-69
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• 1992

Bi-Sr-Ca-Cu-O superconducting system have the low and high Tc phases. In order to get the superconductor above crtitical temperature 100K, we added with Pb and sintered for a long time about 200 hrs. In this study, the influence of superconducting characteristics on the Bi(Pb)SrCaCuO system characteristics on the Bi(Pb)SrCaCuO system dopped Sb was investigate too. Adding Sb of 0.1 mol, the sintering time is short than that dopped Pb only. We could get the critical temperature 102 K at sintered for 24 hrs and 109 K for 210 hrs.