• 한국세라믹학회지
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• 제26권1호
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• pp.139-145
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• 1989

An eutectic melt in the system(Bi2O3)0.85·(Nb2O5)0.15-6Bi2O3·SiO2 was unidirectionally solidfield at a rate of 0.5mm/h under a thermal gradient of 100℃/cm. Double crucibles and seed crystal plate were used in order to botain the composite crystals which had uniform microstructure throughout the ingot. The obtained composite crystals showed uniform microstructure, in which needle-like δ-(Bi2O3)0.85·(Nb2O5)0.15 crystals were arrayed in parallel in a matrix of γ-6Bi2O3·SiO2 single crystal. It was found that the <110> direction of δ-(Bi2O3)0.85·(Nb2O5)0.15 crystal was essentially parallel to the <111> direction of γ-6Bi2O3·SiO2 crystal in the composite crystals. A transverse thin plate of the composite crystals showed a high resolution optical transmission like an optical fiber array, and sharp chatoyancy was observed in the cabochon shaped composite crystals. Then, this may be useful for applications such as screen of a cathode ray tube or artificial cat's eye gem stones.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.728-732
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• 2007

In the present article, a novel fusion expression vector for Escherichia coli was developed based on the pTORG plasmid, a derivative of pET32a. This vector, named pT7MT(GenBank Accession No DQ504436), carries a T7 promoter and it drives the downstream gene encoding Metallothionein 2A(MT2A). There are in-framed multiple cloning sites(MCS) downstream of the MT2A gene. A target gene can be cloned into the MCS and fused to the C-terminal of the MT2A gene in a compatible open reading frame(ORF) to achieve fusion expression. The metal-binding capability of MT2A allows the purification of fusion proteins by metal chelating affinity chromatography, known as $Ni^{2+}$-affinity chromatography. Using this expression vector, we successfully got the stable and high-yield expression of MT2A-GST and MT2A-Troponin I fusion proteins. These two proteins were easily purified from the supernatant of cell lysates by one-step $Ni^{2+}$-affinity chromatography. The final yields of MT2A-GST and MT2A-Troponin I were 30mg/l and 28mg/l in LB culture, respectively. Taken together, our data suggest that pT7MT can be applied as a useful expression vector for stable and high-yield production of fusion proteins.

• Environmental Analysis Health and Toxicology
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• 제17권4호
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• pp.325-332
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• 2002

A helper T(Th)1-mediated response is known to enhance cell -mediated immunity, while a Th2-mediated response is associated with the humoral immunity that if elevated IgE levels and eosinophilia. Prostaglandin (PG)E$_2$results in the decreased capability of Iymphocytes to produce Thl cytokines, with a shift toward a Th2 cytokine response. Chlorpyrifos (CPF) has been reported to impair the blastogenesis and response of T Iymphocytes. CPF also induces delayed febrile effects, which results from the activation of COX -PGE$_2$pathway. The purpose of this study is to determine the effort of CPF on the in vitro production of Th cytokines and the role of PGE$_2$on the CPF-induced production of Th cytokines. Splenocytes obtained from male BALB/c mice were pretreated with CPF(0.1, 1, 10 and 100$\mu$M) in the presence of absence of indomethacin or PGE$_2$for 12 h and then were incubated with concanavalin (Con) A for 48 h. These results showed that CPF remarkedly reduced the production of splenic interleukin (IL)-2 and interferon (IFN)-γ in a dose-dependent manner. CPF significantly increased the splenic IL-4 production at low doses (0.1 and 1$\mu$M) but did not affect at high doses (10 and 100 $\mu$M). Indomethacin reduced the CPF-decreased production of IL-2 and IFN-γ in a dose -dependent manner and significantly attenuated the production of IL-4 increased by CPF 0.1 $\mu$M. High dose of CPF significantly reduced the PGE$_2$-decreased production of IL-2 and IFN-γ, while the PGE$_2$- induced production of IL-4 was significantly enhanced by CPF 1 $\mu$M. These findings suggest that CPF nay down-regulate the immune response of Th 1 type by the suppressed production of IL-2 and IFN-γ, with a shift toward a Th2 cytokine response. The CPF-decreased production of Thl cytokines may not be mediated by endogenous PGE$_2$. Also, CPF may attenuate the exogenous PGE$_2$-decreased Th 1 immune response in a dose--dependent manner but may affect dose-independently the PGE$_2$-induced Th2 immune response.

• BMB Reports
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• 제55권2호
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• pp.92-97
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• 2022

Lysine methylation is one of the most important histone modifications that modulate chromatin structure. In the present study, the roles of the histone lysine demethylases JMJD2a and LSD1 in CK2 downregulation-mediated senescence were investigated. The ectopic expression of JMJD2a and LSD1 suppressed the induction of senescence-associated β-galactosidase activity and heterochromatin foci formation as well as the reduction of colony-forming and cell migration ability mediated by CK2 knockdown. CK2 downregulation inhibited JMJD2a and LSD1 expression by activating the mammalian target of rapamycin (mTOR)-ribosomal p70 S6 kinase (p70S6K) pathway. In addition, the down-regulation of JMJD2a and LSD1 was involved in activating the p53-p21^Cip1/WAF1-SUV39h1-trimethylation of the histone H3 Lys9 (H3K9me3) pathway in CK2-downregulated cells. Further, CK2 downregulation-mediated JMJD2a and LSD1 reduction was found to stimulate the dimethylation of Lys370 on p53 (p53K370me2) and nuclear import of SUV39h1. Therefore, this study indicated that CK2 downregulation reduces JMJD2a and LSD1 expression by activating mTOR, resulting in H3K9me3 induction by increasing the p53K370me2-dependent nuclear import of SUV39h1. These results suggest that CK2 is a potential therapeutic target for age-related diseases.

• 대한수학회논문집
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• 제35권3호
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• pp.745-757
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• 2020

A set {a₁, a₂, …, a_m} of positive integers is called a Diophantine m-tuple if a_ia_j + 1 is a perfect square for all 1 ≤ i < j ≤ m. In this paper, we find the structure of a torsion group of elliptic curves E_k constructed by a Diophantine triple {F_2k, F_2k+2, 4F_2k+1F_2k+2F_2k+3}, and find all integer points on the elliptic curve under assumption that rank(E_k(ℚ)) = 2.

• Applied Biological Chemistry
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• 제7권
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• pp.45-52
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• 1966

This study was carried out to determine how the water soluble, the available $P_2O_5$ and urea-N would change in the course of time, when the mixtures of calcium superphosphate and urea with lime for fertilizer which occurred in Korea and largely contained calcium carbonate were made. Three kinds of materials, i. e., calcium superphosphate, urea and lime for fertilizer were used in this study. Three kinds of mixed fertilizer, i. e., A, B and C were made up by mixing these materials to satisfy the following formula. $$1)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_2H_2(PO_4)+H_2CO_3+NH_3$$ $$2)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_3(PO_4)_2+H_2CO_3+NH_3$$ $$3)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_3(PO_4)_2+H_2CO_3+CaCO_3+NH_3$$ A,B and C were placed in desiccators respectively a six month period. During the time of storage, the water soluble, the available phosphoric acid and urea-N were measured once a month, seven times with the control measurement. The results may be summarized as follows. 1. None of A, B and C showed any change in the urea-N with the lapse of time. This fact indicated that the combination of calcium superphosphate and urea with lime for fertilizer was not unfavourable. 2. A, B and C decreased in the amount of water soluble $P_2O_5$ with the passage of time. This fact indicated that the mixing of calcium superphosphate and urea with lime for fertilizer was unfeasible. 3. The available $P_2O_5$ in any of A,B and C did not undergo a change as time went by. This fact suggested that the combination of calcium superphate and urea with lime for fertilizer was favourable.

• 한국작물학회지
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• 제65권4호
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• pp.416-425
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• 2020

본 연구는 최근 개발된 조생종 사료용 옥수수 품종에 대한 2기작(전기작 및 후기작)의 생육특성 및 생산성을 구명하고 조사료 생산 확대의 가능성을 검토하고자 수행하였다. 1. 파종기에서 출사기까지의 전기작 출사일수는 78일이 소요되었고 후기작은 52일이 소요되었다. 출사기에서 수확기까지의 전기작 소요일수는 26일이 소요되었고 후기작은 46일이 소요되었다. 2. 파종기에서 출사기까지의 전기작 적산온도는 1,512℃이였고 후기작은 1,246℃이었다. 전기작과 후기작 간의 적산온도는 266℃ 차이가 있었으며 후기작 적산온도가 전기작보다 적었다. 파종기에서 수확기까지의 전기작 적산온도는 2,198℃이였고 후기작은 1,951℃이었다. 전기작과 후기작 간의 적산온도는 247℃ 차이가 있었으며 후기작 적산온도가 전기작보다 적었다. 3. 건물수량은 전기작(1,637 kg/10a)과 후기작(1,565 kg/10a)이 비슷하였다. 전기작의 품종 간 건물수량은 신황옥2호(1,673 kg/10a), 신황옥(1,660 kg/10a), 광평옥(1,579 kg/10a)이 모두 비슷하였다. 후기작의 품종 간 건물수량은 신황옥(1,669 kg/10a)과 광평옥(1,651 kg/10a)이 비슷하였으며 신황옥2호(1,374 kg/10a)가 가장 적었다. TDN수량은 전기작(1,135 kg/10a)과 후기작(1,037 kg/10a)이 비슷하였다. 전기작의 품종 간 TDN수량은 신황옥2호(1,183 kg/10a), 신황옥(1,158 kg/10a), 광평옥(1,063 kg/10a)이 모두 비슷하였다. 후기작의 품종 간 TDN수량은 신황옥(1,150 kg/10a)과 광평옥(1,100 kg/10a)이 비슷하였으며 신황옥2호(970 kg/10a)가 가장 적었다. 4. 총 건물수량은 신황옥(3,329 kg/10a)과 광평옥(3,230 kg/10a)이 비슷하였으며 3품종 중에 신황옥2호(3,047 kg/10a)가 가장 적었다. 총 TDN수량은 신황옥(2,307 kg/10a), 광평옥(2,162 kg/10a), 신황옥2호(2,152 kg/10a) 모두 비슷하였다.

• 대한화학회지
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• 제37권1호
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• pp.76-82
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• 1993

Ca(II) 와 Tl(I)으로 교환되고 완전히 진공 탈수된 2개의 제올라이트 A 결정 즉, $Ca_{5.6}Tl_{0.8}-A (a = 12.242(2){\AA})\;와\;Ca_{1.4}Tl_{9.2}-A (a = 12.191(1){\AA})$의 구조를 21(1)$^{\circ}C$에서 입방공간군 Pm3m을 사용하여 X-선 단결정 회절법으로 해석하였다. 이들 두 결정은 총농도를 0.05M로 한 $Ca(NO_3)_2$ 와 $$TINO_3$ 혼합용액을 사용하여 흐름법으로 이온교환하여 만들었고 탈수는 360$^{\circ}C$ 및 $2{\times}10^{-6}\;torr$에서 2일간 행하였다. $Ca_{5.6}Tl_{0.8}-A$ 구조에서는 I > 3$\sigma$(I)인 회절점 179개를 사용하여 $R_1$ = 0.072 와 $R_2$ = 0.076까지, $Ca_{1.4}Tl_{9.2}-A$구조에서는 I > 3$\sigma$(I)인 회절점 226개를 사용하여 $R_1$ = 0.048 and $R_2$ = 0.043까지 정밀화시켰다. 두 구조에서 Ca(II) 이온은 3개의 6-링 산소와 결합하면서 3회 회전축 상에 위치하였다. 단위세포당 교한된 양이온의 총수가 8개 이상이면 $Ca^{2+}$ 이온은 6-링 자리에, $Tl^+$ 이온은 8-링 자리에 우선적으로 위치한다.

• 한국결정학회지
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• 제6권1호
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• pp.1-13
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• 1995

융액인상법에 의해 Cr:A12O3 및 Ti:A12O3 단결정을 육성한 후 인상속도, 회전속도, 주입이온 및 결정육성 분위기와 같은 결정육성요소가 결정의 품질에 미치는 영향을 조사하고, 육성된 결정의 레이저 효율과 분광학적 물성을 측정하였다. 직경 20mm, 길이 100-135mm 크기의 결정을 <001>방위로 육성하였다. Cr:A12O3의 주입농도 0.5w/o, 인상속도 2.0mm/hr, 회전속도 30rpm으로 할 때 질소기체에 의한 비활성 분위기하에서 양질의 Cr:A12O3 결정이 얻어졌다. Ti:A12O3 단결정은 TiO2를 0.25w/o 주입하고 인상속도 1.5mm/hr, 회전속도 30rpm으로 육성할 때, 수소기체에 의한 환원성 분위기하에서 양질의 결정이 얻어졌다. 원자가가 변화하지 않는 Cr3+이온은 원자가가 변화하는 Ti4+이온을 주입할 때보다 효과적으로 탈포되었으며, Fe3+이온은 Ti3+이온에 대해 탈포를 촉진하는 효과가 있었다. Ti:A12O3 단결정 육성시 90% N2 - 10% H2 혼합기체를 사용하여 환원성 분위기를 조성하는 것이 원자가 변화 및 탈포에 좋은 효과를 나타내었다. 흡수 및 형광방출 스펙트럼 조사 결과 Cr:A12O3 단결정에서 4A2 → 4F2 및 4F1 천이에 의한 흡수와 E→4A2(R1) 및 2A→4A2(R2) 천이에 의한 형광방출 천이를 확인하였다. R1 및 R2 천이의 레이저 주파장은 각각 696±5nm 및 692 ±5nm이고, 각 천이의 형광선폭은 12A, 형광수명은 152 μsec로 측정되었다. Ti:A12O3 단결정에서는 4T2→ 4E의 흡수천이와 4E→4T2의 천이에 의해 650nm-1050nm 범위에서 파장가변이 가능한 형광방출천이가 일어남을 확인하였으며 형광수명은 147μsec, figure of merit는 125.4로 측정되었다. Ti:A12O3 단결정으로부터 제조한 레이저봉을 이용하여 레이저 공진한 결과 레이저 발진효율은 9%로 측정되었다.

• 대한수학회보
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• 제57권4호
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• pp.839-850
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• 2020

For functions f(z) = z + a₂z² + a₃z³ + ⋯ belonging to particular classes, this paper finds sharp bounds for the initial coefficients a₂, a₃, a₄, as well as the sharp estimate for the second order Hankel determinant H₂(2) = a₂a₄ - a₂³. Two classes are treated: first is the class consisting of f(z) = z + a₂z² + a₃z³ + ⋯ in the unit disk 𝔻 satisfying $$\|\(\frac{z}{f(z)}\)^{1+{\alpha}}\;f^{\prime}(z)-1\|<{\lambda},\;0<{\alpha}<1,\;0<{\lambda}{\leq}1.$$ The second class consists of Bazilevič functions f(z) = z+a₂z²+a₃z³+⋯ in 𝔻 satisfying $$Re\{\(\frac{f(z)}{z}\)^{{\alpha}-1}\;f^{\prime}(z)\}>0,\;{\alpha}>0.$$