• Journal of the Chungcheong Mathematical Society
• /
• v.27 no.2
• /
• pp.309-317
• /
• 2014

In this paper, we give chemical hyperstructures of chemical reactions for a set of vanadium(V).

• Proceedings of the Korean Ceranic Society Conference
• /
• 2004.04b
• /
• pp.27.2-27.2
• /
• 2004

• Structural Engineering and Mechanics
• /
• v.27 no.2
• /
• pp.259-262
• /
• 2007

• Food Science of Animal Resources
• /
• v.27 no.1
• /
• pp.110-116
• /
• 2007

Lactobacillus salivarius subsp. salivarius Nam27 with a high ${\beta}$-galactosidase activity was selected for enzymatic characterization. For purification, cell pellet was disrupted by Bead Beater, by DEAE-Sepharose and Mono-Q chromatography. The specific activity of the purified enzyme was 5,312 units/mg. The molecular weight of native monomeric ${\beta}$-galactosidase was estimated to be 30,000 dalton (monomer) by the SDS-PAGE. The optimum temperature and optimum pH were $50^{\circ}C$ and 5.0, respectively. This enzyme was stable between 35 and $55^{\circ}C$. ${\beta}$-galactosidase activity was lost rapidly above pH 7.0. But ${\beta}$-galactosidase was more stable at pH 4.0 (acidic conditions). And ${\beta}$-galactosidase activity was lost rapidly above $65^{\circ}C$ after 10 min incubation. $Ca^{2+}$ and $Zn^{2+}$ metal ions enhanced ${\beta}$-galactosidase activity by 164.09% and 127.37% while $Cu^{2+}$, $Fe^{3+}$ and $Mn^{2+}$ lowered ${\beta}$-galactosidase activity by 58.29%,85.10% and 77.66% respectively. Other metal ions didn't affect ${\beta}$-galactosidase activity significantly.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1289-1292
• /
• 2006

Potassium(I) with 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate (L) assembles to K($H_2O$)L (L = 5,7-dihydroxy-6,4'-dimethoxyisoflavone-3'-sulfonate). It was characterized by single-crystal X-ray diffraction, element analysis, IR and $^1H$ NMR spectroscopy. It crystallizes in the monoclinic space group $P2_1$/n and reveals a seven-coordinate complex. Polyhedra potassium chains, C-H${\cdot}{\cdot}{\cdot}\pi$ and C-H${\cdot}{\cdot}{\cdot}$O and O-H${\cdot}{\cdot}{\cdot}$O hydrogen bonds lead K($H_2O$)L to a three-dimensional network structure. The biological activity of resistance to hypoxia was tested, and the results showed that the biological activity of resistance to hypoxia of K($H_2O$)L is as good as that of its precursor, irisolidone.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.5
• /
• pp.759-761
• /
• 2006

The compound B(C6F5)3 and its variations have been widely employed as alkyl carbanion abstracting reagents to produce metallocene cations for olefin polymerization.1-3 Weakly coordinating anions containing boron can greatly improve the activity of metallocene catalysts used in industrial olefin polymerization4 and thus group IV and V metallocene complexes of the organohydroborate anions have been intensively investigated.5 Recently, many organohydroborate metallocene complexes have been reported by Shore and co-workers.6-8 A common structural feature of those complexes is the three-center two electron M-H-B bond, like that observed in transition metal tetrahydroborate complexes but the reactivity and fluxional behavior of organohydroborate complexes are unlike those of the tetrahydroborate analogues.6 Although many of those metallocenes have been synthesized, few complexes could be used in the olefin polymerization and then this laboratory has been involved in the chemistry of the cyclic organohydroborate anions, and their group IV metallocene derivatives for the catalyst.9 Described here is recent work that led to the preparation of a novel cyclic organohydroborate hafnocene complex (h5-C5H5)2Hf ？(μ-H)2BC8H14 ,Cl. The hafnocene complex contains the three-center two electron bond Hf-H-B10 in which the hydride abstraction for olefin polymerization may occur.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.11
• /
• pp.1158-1161
• /
• 1997

The potentiometric methods have been used to determined the protonation constants (logKiH) for the synthesized 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N''-tri(methylacetic acid) [N3O3-tri(methylacetic acid)] and the stability constants (logKML) of the complexes of divalent and trivalent metal ions with the ligand N3O3-tri(methylacetic acid). The protonation constants of N3O3-tri(methylacetic acid) were 9.70 for logK1H, 9.18 for logK2H, 7.27 for logK3H, 3.38 for logK4H, and 2.94 for logK5H. The stability constants for the complexes of divalent metal ions with N3O3-tri(methylacetic acid) were 10.39 for Co2+, 10.68 for Ni2+, 13.45 for Cu2+, and 13.00 for Zn2+. The order of the stability constants for the complexes of the divalent metal ions with N3O3-tri(methylacetic acid) was Co2+ < Ni2+ < Zn2+ < Cu2+. The stability constants for the complexes of trivalent metal ions with N3O3-tri(methylacetic acid) were 16.20 for Ce3+, 16.40 for Eu3+, 16.27 for Gd3+, and 15.80 for Yb3+. The results obtained in this study were compared to those obtained for similar ligands, 1,7-dioxa-4,10,13-triazacyclopentadecane-N,N',N"-tri(methylacetic acid) and 1,7,13-trioxa-4,10,16-triazacyclooctadecane-N,N',N"-triacetic acid, which have been previously reported.

• Journal of Aquaculture
• /
• v.10 no.1
• /
• pp.69-76
• /
• 1997

Chromatium sp., densely populated on the bacterial plate of Lake Kaiike throughout the seasons, possibly fix N2 and concurrently produce H2 N2 Fixation and H2 production by Chromatium sp. were performed under photoautotrophic growth condition, and of which rates were much higher and showed expontial growth phase. Bacterial plater samples from Lake Kaiike collected on July 27, 1994 were used to know the effect of the light or H2S on N2 fixation and H2 productin by the bacteria. At low light intensity (250 lux), low rates of N2 fixation and H2 production were detected after 18 hours. However, high rates of the production were observed under the condition of high light intensity (1000 lux). On the other hand, a very low rate of N2 fixation was observed without an addition of H2S, while the bacterial rapilly increased N2 fixation and H2 production after adding H2S and the highest rate was observed in case of adding 20mg H2S-S/$m\ell$ to the bacterial plates.

• BMB Reports
• /
• v.53 no.5
• /
• pp.266-271
• /
• 2020

Breast cancer encompasses a major portion of human cancers and must be carefully monitored for appropriate diagnoses and treatments. Among the many types of breast cancers, triple negative breast cancer (TNBC) has the worst prognosis and the least cases reported. To gain a better understanding and a more decisive precursor for TNBC, two major histone modifications, an activating modification H3K4me3 and a repressive modification H3K27me3, were analyzed using data from normal breast cell lines against TNBC cell lines. The combination of these two histone markers on the gene promoter regions showed a great correlation with gene expression. A list of signature genes was defined as active (highly enriched H3K4me3), including NOVA1, NAT8L, and MMP16, and repressive genes (highly enriched H3K27me3), IRX2 and ADRB2, according to the distribution of these histone modifications on the promoter regions. To further enhance the investigation, potential candidates were also compared with other types of breast cancer to identify signs specific to TNBC. RNA-seq data was implemented to confirm and verify gene regulation governed by the histone modifications. Combinations of the biomarkers based on H3K4me3 and H3K27me3 showed the diagnostic value AUC 93.28% with P-value of 1.16e-226. The results of this study suggest that histone modification analysis of opposing histone modifications may be valuable toward developing biomarkers and targets for TNBC.

• Publications of The Korean Astronomical Society
• /
• v.27 no.4
• /
• pp.161-164
• /
• 2012

We performed a spectroscopic survey for cometary volatiles with the Infrared Camera onboard the Japanese infrared satellite AKARI. The observations were carried out in the near-infrared wavelength range in the period from 2008 June to 2010 January. In this paper, we summarize the observations and results of the AKARI survey for the mixing ratios of major volatiles in comets. We derived the $2.5-5{\mu}m$ spectra of 18 comets including both Oort cloud comets and Jupiter-family comets. Prominent emission bands in the observed spectra are the fundamental vibrational bands of water ($H_2O$) at $2.7{\mu}m$ and carbon dioxide ($CO_2$) at $4.3{\mu}m$. The fundamental vibrational band of carbon monoxide (CO) at $4.7{\mu}m$ and the broad emission feature probably related to C-H bearing molecules can also be recognized around the $3.4-3.5{\mu}m$ region in some comets. We detect $CO_2$ in 17 out of 18 comets, and derived gas production rate ratios of $CO_2$ with respect to $H_2O$ in 17 comets. We detect a reliable CO emission band only in three of the comets. Our data set provides the largest homogeneous database of $CO_2/H_2O$ ratios in comets obtained so far.