• Journal of the Korean Chemical Society
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• v.17 no.1
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• pp.20-24
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• 1973

The average fission neutron cross sections were determined for the following reactions, $^{93}Nb(n,\alpha)^{90}Y$, $^{90}Zr(n,p)^{90}Y$,$^{93}Nb(n,\alpha)^{90m}Y$and$^{90}Zr(n,p)^{90m}Y$. The cation exchange column was used for the quantitative separation of the product nuclides using $\alpha-$hydroxyisobutyric acid as the eluent. The absolute activites of $^{90m}Y$ and $^{90}Y$were determined by the gamma ray spectrometry and a calibrated $2\pi$gas flow counter, respectively. The cross sections of $^{93}Nb(n,\alpha)^{90}Y$, $^{90}Zr(n,p)^{90}Y$,$^{93}Nb(n,\alpha)^{90m}Y$and $^{90}Zr(n,p)^{90m}Y$ reactions were found to be$0.14\pm0.01mb$, $0.83\pm0.02mb$, $0.018\pm0.02mb$ and $0.33\pm0.02mb$, respectively. The possible use of $^{90m}Y$ instead of $^{90}Y$ was discussed as a better means for the determination of niobium.

• Biomolecules & Therapeutics
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• v.27 no.5
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• pp.423-434
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• 2019

HSP90 is a molecular chaperone that increases the stability of client proteins. Cancer cells show higher HSP90 expression than normal cells because many client proteins play an important role in the growth and survival of cancer cells. HSP90 inhibitors mainly bind to the ATP binding site of HSP90 and inhibit HSP90 activity, and these inhibitors can be distinguished as ansamycin and non-ansamycin depending on the structure. In addition, the histone deacetylase inhibitors inhibit the activity of HSP90 through acetylation of HSP90. These HSP90 inhibitors have undergone or are undergoing clinical trials for the treatment of cancer. On the other hand, recent studies have reported that various reagents induce cleavage of HSP90, resulting in reduced HSP90 client proteins and growth suppression in cancer cells. Cleavage of HSP90 can be divided into enzymatic cleavage and non-enzymatic cleavage. Therefore, reagents inducing cleavage of HSP90 can be classified as another class of HSP90 inhibitors. We discuss that the cleavage of HSP90 can be another mechanism in the cancer treatment by HSP90 inhibition.

• BMB Reports
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• v.42 no.10
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• pp.623-630
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• 2009

Hsp90, an evolutionarily conserved molecular chaperone, is involved in the folding, stabilization, activation, and assembly of a wide range of 'client' proteins, thus playing a central role in many biological processes. Especially, several oncoproteins act as Hsp90 client proteins and tumor cells require higher Hsp90 activity than normal cells to maintain their malignancy. For this reason, Hsp90 has emerged as a promising target for anti-cancer drug development. It is still largely unknown how Hsp90 can recognize structurally unrelated client proteins. However, recent progress in structural studies on Hsp90 and its interaction with various co-chaperones has broadened our knowledge of how the Hsp90 ATPase activity, which is essential for its chaperone function, is regulated and coupled with the conformational changes of Hsp90 dimer. This review focuses on the roles of various Hsp90 co-chaperones in the regulation of the Hsp90 ATPase cycle, as well as in the selection of client proteins. In addition, the current development of Hsp90 inhibitors based on the structural information will be discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.264-267
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• 2008

Many researchers have studied synthesis method of 90/150 group CA. However, there is a lack of researches for synthesis method of 90/150 nongroup CA. In this paper we report some interesting properties of 90/150 multiple-attractor CA in which all of the cycles are of unit length. 90/150 multiple-attractor CA is a class of nongroup CA. And we propose a construction of 90/150 single-attractor CA. Also we construct 90/150 multiple-attractor CA derived from 90/150 single-attractor CA.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.33-42
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• 1991

A pot experiment on the Sr-90 uptake by the barley from a loamy-sandy soil of pH 6.05 treated with Sr-90 and slaked lime was carried out in a green house. The rate of Sr-90 uptake at maturity was, on an average, 0.41% for a naked barley Neolssalbori and 0.23% for a covered one Olbori. Transfer coefficients of Sr-90 for the former were higher than those for the latter by about 30-60% depending on the plant parts. There were, on the whole, not significant differences in the rate and in the coefficient among Sr-90 concentration treatments. Slaked lime addition equivalent to about 94kg/10a was not effective for lessening Sr-90 uptake or diminishing Sr-90 transfer coefficient. As transfer coefficients, 1.51, 4.45, 0.35, and 1.30, on the dry weight basis, could be proposed for the stem, leaf, seed, and whole top of the barley, respectively. Growth inhibition or yield decrease due to Sr-90 uptake was not observed.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.460-469
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• 2017

Heat shock proteins (HSPs) are induced as a self-defense mechanism of cells when exposed to various external stresses, such as high fever, infection, free radicals, and heavy metals. They affect the prognosis in the process of tumor formation. HSP is classified into four families: HSP27, HSP60, HSP90, and HSP100, depending on molecular weight. Heat shock protein 90 (HSP90), a molecular chaperone, plays an important role in the cellular protection against various stressful stimuli and in the regulation of cell cycle progression and apoptosis. In the present study, we assessed the differential expression of HSP90 family proteins in non-small cell lung cancer (NSCLC), and the correlation of their expression levels with clinicopathologic factors and patient survival rates. The result of this study can be summarized as follows; $HSP90{\alpha}$ showed higher expression in patients with no lymphovascular invasion (p=0.014). $HSP90{\beta}$ showed a higher expression of squamous cell carcinoma (p=0.003), and an over expression of glucose-related protein (GRP94) was significantly associated with poor differentiation (p=0.048). However, none of the HSP90 proteins showed a significant association with the survival status in patients with NSCLC. This study also indicates that $HSP90{\alpha}$ might contribute more to the carcinogenesis of NSCLC than $HSP90{\beta}$, and GRP94 and isoform selectivity should be considered when HSP90 inhibitors are studied or utilized in the treatment of NSCLC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1064-1069
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• 2007

This paper proposes the highly miniaturized active $90^{\circ} power combiner for application to MMIC. Conventional passive $90^{\circ} power combiners can't be integrated on MMIC because of their very larger size. Therefore, the highly miniaturized $90^{\circ} power combiners are required for a development of highly integrated MMIC. For this paper, the highly miniaturized active $90^{\circ} power combiner employing InGaP/GaAs HBT was fabricated on GaAs substrate for application to highly integrated MMIC. A size of fabricated active $90^{\circ} power combiner was $2.42{\times}1.05$ mm, which was 2.2 % of conventional passive $90^{\circ} power combiner. The fabricated active $90^{\circ} power combiner showed a gain characteristic about 10 dB and a good phase-difference coupling characteristic of $-92.6^{\circ} than conventional passive $90^{\circ} power combiner at 2.4 GHz. The highly miniaturized active $90^{\circ} power combiner exhibited good RF performances comparable to conventional passive $90^{\circ} power combiners. This work is the first report of an active $90^{\circ} power combiner.

• Journal of Life Science
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• v.26 no.7
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• pp.826-834
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• 2016

The present investigation was undertaken to examine the effectiveness of the combination treatment of an Hsp90 inhibitor and a SIRT1 inhibitor on suppressing the growth of chemo-resistant human cancer cells. We showed that inhibition of SIRT1 effectively potentiated the cytotoxicity of 17-allylamino-17-demethoxygeldanamycin (17-AAG) and reversed Hsp90 inhibitor resistance in multidrug-resistant (MDR) human ovarian HeyA8-MDR cells. Amurensin G, a potent natural SIRT1 inhibitor, enhanced Hsp90 inhibitor-mediated abrogation of the Hsp90 chaperone function and accelerated degradation of mutated p53 (mut p53), an Hsp90 client protein, by up-regulation of ubiquitin ligase CHIP. Knock-down of CHIP significantly attenuated amurensin G-induced mut p53 degradation. Down-regulation of mut p53 reduced the expression of heat shock factor1 (HSF1)/heat shock proteins (Hsps), a major cause of Hsp90 inhibitor resistance, which led to sensitization of the MDR cells to the Hsp90 inhibitor by the SIRT1 inhibitor. Amurensin G potentiated cytotoxicity of the Hsp90 inhibitor in HeyA8-MDR cells through suppression of 17-AAG-induced Hsp70 and Hsp27 induction via down-regulation of mut p53/HSF1, and it caused activation of PARP and inhibition of Bcl-2. Our data suggests that SIRT1 inhibitors could be used to sensitize MDR cells to Hsp90 inhibitors, possibly through suppression of the mut p53/HSF1-dependent pathway, and a novel mut p53-directed action of SIRT1 inhibition could effectively prevent mut p53 accumulation in MDR cells.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.557-564
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• 1995

The 90 kDa-heat shock protein (HSP90) is one of the major ubiquitous heat shock proteins induced by a vadety of ceilular stresses. HSP90 Is constitutively synthesized even under nonstressed condidons and found In association with several regulatory and structural proteins such as protein kinases and steroid hormone receptors. In the present study, to facilitate its biochemical characterization, HSP90 was pudfied from chick muscle by sequential column chromatography steps including DEAE- cellulose, hydroxyapatite, and Sephacryl S-300 gel filtration and monoclonal antillodies specific to HSP90 were produced by the inurine hybridomal technique. We report the production of 4 posItive hybridoma clones, named as A204, C112, C302 and A204, C112, C302. Among these MoAbs, Cl 12 strongly reconnized chick HSP90 in Western blot and native immunoprocipitation. In addition, C112 showed the crossreactivitles against HSP90 from human, rabbit, mouse, fish and chick but not from Drosophila and E. coil.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.1
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• pp.10-16
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• 2010

90/150 CA is a CA completely specified by using rule 90 and rule 150. Since 90/150 CA whose minimal and characteristic polynomials are identical has outstanding randomness, this CA is more attractive than LFSR. Sarkar proposed a scheme based on the 90 uniform CA and the 150 uniform CA. That scheme provided authentication by digital signature and other basic security requirements like confidentiality. In this paper we analyze 90 or 150 uniform CA and give a synthesis method of 2n-cell uniform CA and (2n+1)-cell uniform CA using a special n-cell 90/150 CA. And we propose an effective method of computation of characteristic polynomial corresponding to uniform CA.