• Journal of the Korean Society of Tobacco Science
• /
• v.25 no.1
• /
• pp.59-69
• /
• 2003

The adsorption characteristics of H$_2$S, NH$_3$and $CH_3$SH on the graphite carbon have been investigated using Grand Canonical Monte Carlo(GCMC) method with universal force field (UFF) and dreiding force field. Most of the activated carbons used in vapor phase adsorption have the micropore of 6$\AA$ to 20$\AA$ and the specific surface area of ca. 1000 m$^2$/g, as the result of $N_2$ adsorption by BET method. For the more efficient comparison, the activated carbons have been manipulated with different pore sizes. The adsorption characteristics of H$_2$S, NH$_3$and $CH_3$SH have been considered at various temperatures and pressures. The adsorption amount using Dreiding force field is predicted to be lower than that using UFF. As the temperature is going to high, the adsorption amount of adsorbates is decreased due to their vaporization. Considering the pore size effect, the adsorption characteristic depends on the adsorbate size, polarity and interaction between adsorbates, etc. At all cases employed in this study, NH$_3$ is barely adsorbed and $CH_3$SH is preferentially adsorbed on the graphite carbon. Our theoretical result is qualitatively good agreement with the experimental observation. However, there are some quantitative discrepancies depending on the functional groups and pore size distribution on the real activated carbons used in experiment.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.5
• /
• pp.653-658
• /
• 2017

To evaluate the effects of amylose content and dissolution media on the molecular structure of maize starch, changes in the hydrodynamic diameter of starch molecules were assessed via dynamic light scattering depending on amylose content and dissolution media. As the amylose content of starch increased, the hydrodynamic diameter of starch molecules proportionally decreased from 204 to 92 nm. To alter ionic strength, hydrogen bonding, or polarity of dissolution media, various contents of NaCl (1, 2, or 3 M), urea (1, 2, or 3 M), or 1-butanol (0.1, 0.5, or 1.0%) were added to media, respectively, resulting in increased hydrodynamic diameter of starch. However, the degree of expansion was dependent on amylose content and the concentration and/or type of additive. The hydrodynamic diameter of starch molecules exhibited significant correlation with amylose content obtained by size exclusion chromatography, regardless of dissolution conditions.

• KIPS Transactions on Software and Data Engineering
• /
• v.8 no.10
• /
• pp.421-426
• /
• 2019

In this paper, we propose a method to visualize the geometric features of the contact region between proteins in a protein complex. When proteins or ligands are represented as curved surfaces with irregularities, the property that the two surfaces contact each other without intersections is called shape compatibility. Protein-Protein or Protein-Ligand docking researches have shown that shape complementarity, chemical properties, and entropy play an important role in finding contact regions. Usually, after finding a region with high shape complementarity, we can predict the contact region by using residual polarity and hydrophobicity of amino acids belonging to this region. In the research for predicting the contact region, it is necessary to investigate the geometrical features of the contact region in known protein complexes. For this purpose, it is essential to visualize the geometric features of the molecular surface. In this paper, we propose a method to find the contact region, and visualize the geometric features of it as normal vectors and mean curvatures of the protein complex.

• Membrane and Water Treatment
• /
• v.2 no.3
• /
• pp.137-145
• /
• 2011

Membrane processes are major breakthrough for the removal of organic pollutants in water remediation. The separations of solutes depend on nature of the membranes and solutes. The separation performance depends on the nature of the solutes (i.e., molecular volume, polarity, and hydrophobicity) for the same membrane. As 4-chlorophenol is of more dipolemoment compared to 2-chlorophenol, the orientation of the molecule enables it pass through the pores of the membrane, which is of negatively charged and thus separation order follows: 2-chlorophenol > 4-chlorophenol. Hydrophobicity factor also supports the order. Addition of sodium dodecyl sulfate (SDS) to chlorophenol solution shows remarkable increase in separation performance of the membrane. The improvement in separation is 1.8 and 1.5 times for 4- and 2- chlorophenol consecutively in case of 0.0082 M SDS (1cmc = 0.0082 M) in the solution. 4-chlorophenol has better attachment tendency with SDS because of its relatively more hydrophobic nature and thus reflects in performance i.e. the separation performance of 4-chlorophenol with SDS through the membrane is better compared to 2-chlorophenol.

• BMB Reports
• /
• v.48 no.6
• /
• pp.360-366
• /
• 2015

Colorectal cancer (CRC), the third most common cancer worldwide, also has the highest rate of cancer-related morbidity and mortality. WNT signaling is initiated by binding of WNT to various receptors, including frizzleds (FZDs), and plays a critical role in CRC and other tumor development by regulating proliferation, differentiation, migration, apoptosis, and polarity. Among the members of the FZD family, FZD6 is broadly expressed in various tissues, and its overexpression has been reported in several cancers, suggesting an important role in cancer development. In this study, we investigated the expression of FZD6 in patients with CRC and found it to be increased in tumors, as compared to paired adjacent non-tumor tissues. Additionally, we found that FZD6 expression was negatively regulated by miR199a5p in CRC cells. These results suggest that overexpression of FZD6, mediated by reduced expression of miR-199a-5p, may play an important role in the development of CRC. [BMB Reports 2015; 48(6): 360-366]

• BMB Reports
• /
• v.50 no.12
• /
• pp.601-609
• /
• 2017

Mammalian target of rapamycin complex 1 (mTORC1) plays a major role in cell growth, proliferation, polarity, differentiation, development, and controls transitioning between anabolic and catabolic states of the cell. It collects almost all extracellular and intracellular signals from growth factors, nutrients, and maintains cellular homeostasis, and is involved in several pathological conditions including, neurodegeneration, Type 2 diabetes (T2D), obesity, and cancer. In this review, we summarize current knowledge of upstream signaling of mTORC1 to explain etiology of T2D and hypertriglyceridemia, in which state, the role of telomere attrition is explained. We discuss if chronic inhibition of mTORC1 can reverse adverse effects resulting from hyperactivation. In conclusion, we suggest the regulatory roles of telomerase (TERT) and hexokinase II (HKII) on mTORC1 as possible remedies to treat hyperactivation. The former inhibits mTORC1 under nutrientrich while the latter under starved condition. We provide an idea of TOS (TOR signaling) motifs that can be used for regulation of mTORC1.

• BMB Reports
• /
• v.28 no.5
• /
• pp.458-463
• /
• 1995

Two apparent rho-independent transcription terminator structures within the coding sequence of aceK have been destroyed to access their roles in the differential expression between aceA and aceK in the glyoxylate bypass operon of E. coli. The effect of mutations on the expression of aceK was evaluated in two different ways: one by maxicell labeling and the other by lacZ fusion gene construction. The maxicell labeling experiment with the mutant operon clones has failed, like that of the wild type operon clone, to visibly show isocitrate dehrogenase (IDH) kinase/phosphatase, the product of aceK, on the autoradiogram of a protein gel. When the same mutations were introduced into an aceK::lacZ fusion gene to quantitatively evaluate the mutational effect, the activity of ${\beta}-galactosidase$ in neither of the mutant versions of the fusion gene was elevated significantly enough to explain the degree of polarity observed in this region. Thus, we conclude that neither of these intragenic, apparent rho-independent transcription terminator structures, which have long been suspected as a major determinant in the down regulation of aceK, really act as a premature transcriptional terminator.

• Applied Science and Convergence Technology
• /
• v.23 no.6
• /
• pp.317-327
• /
• 2014

In order to develop nano-devices with much lower power consumption for beyond-CMOS applications, the fundamental understanding and precise control of the electronic properties of ultrathin transition metal oxide (TMO) films are strongly required. The metal-insulator transition (MIT) is not only an important issue in solid state physics, but also a useful phenomenon for device applications like switching or memory devices. For potential use in such application, the electronic structures of MIT, observed for TMO nano-structures, have been investigated using a synchrotron radiation angle-resolved photoelectron spectroscopy system combined with a laser molecular beam epitaxy chamber and a scanning photoelectron microscopy system with 70 nm spatial resolution. In this review article, electronic structures revealed by soft X-ray nano-spectroscopy are presented for i) polarity-dependent MIT and thickness-dependent MIT of TMO ultrathin films of $LaAlO_3/SrTiO_3$ and $SrVO_3/SrTiO_3$, respectively, and ii) electric field-induced MIT of TMO nano-structures showing resistance switching behaviors due to interfacial redox reactions and/or filamentary path formation. These electronic structures have been successfully correlated with the electrical properties of nano-structured films and nano-devices.

• BMB Reports
• /
• v.51 no.1
• /
• pp.45-53
• /
• 2018

Mammalian target of rapamycin complex 1 (mTORC1) plays a major role in cell growth, proliferation, polarity, differentiation, development, and controls transitioning between anabolic and catabolic states of the cell. It collects almost all extracellular and intracellular signals from growth factors, nutrients, and maintains cellular homeostasis, and is involved in several pathological conditions including, neurodegeneration, Type 2 diabetes (T2D), obesity, and cancer. In this review, we summarize current knowledge of upstream signaling of mTORC1 to explain etiology of T2D and hypertriglyceridemia, in which state, the role of telomere attrition is explained. We discuss if chronic inhibition of mTORC1 can reverse adverse effects resulting from hyperactivation. In conclusion, we suggest the regulatory roles of telomerase (TERT) and hexokinase II (HKII) on mTORC1 as possible remedies to treat hyperactivation. The former inhibits mTORC1 under nutrient-rich while the latter under starved condition. We provide an idea of TOS (TOR signaling) motifs that can be used for regulation of mTORC1.

• Journal of the Korean Chemical Society
• /
• v.37 no.3
• /
• pp.335-343
• /
• 1993

The maximum absorption wavelengths of charge-transfer complexes of naphthalene, ${\alpha}-and{\beta}-methyl$ naphthalene and 1,2-, 2,3-and 2,6-dimethyl naphthalene with chloranil have been measured with a UV spectrophotometer in ethylene chloride, methylene chloride, and chloroform at 10, 15, 20, and 25$^{\circ}C$. This absorption band was interpreted as the charge transfer band of a 1 : 1 molecular complex, and the maximum absorption wavelength was changed as a function of solvent and temperature. Their formation constants (K$_f$) were decreased with the polarity of solvent and the increase of temperature. Thus, the influences of solvent and temperature on the formation constant have been discussed as consideration of thermodynamic properties, and the electronic and steric effects of electron donors on formation constant have been also discussed.