• Journal of Environmental Science International
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• v.16 no.9
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• pp.1091-1098
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• 2007

Activated carbon was prepared from waste citrus peels by chemical activation with $ZnCl_2$. The optimal condition of carbonization was at $300^{\circ}C$ for 1.5 hr. Activation experiments with carbonized samples prepared at optimal carboniztion condition were carried out under various conditions such as activation temperature of 400 to $900^{\circ}C$, activation time of 0.5 to 2.0 hr, and $ZnCl_2$ ratio of 100 to 300%. In order to investigate the physical properties of the activated carbons prepared, iodine adsorptivities and specific surface areas were measured and their morphologies were observed from scanning electron microscopy. As $ZnCl_2$ ratio increased, activation yield decreased, while iodine adsorptivity and specific surface area increased. The optimal condition of activation was at 300% $ZnCl_2$ ratio and $300^{\circ}C$ for 1.5 hr, and then iodine adsorptivity and specific surface area was measured as about 862 mg/g and $756m^2/g$, respectively. SEM photography showed that the surface morphology was changed and many active pore were produced by chemical activation.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.45-50
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• 2008

In this work, stainless steel mesh-supported activated carbons were prepared using phenolic resin and cellulose fiber. $ZnCl_2$ was used as a activation reagent in this work. $ZnCl_2$-chemical activation method has been proposed to produce highly porous activated carbons. The objectives of this work were to develop an optimal condition for manufacturing activated carbon assemblies screen from stainless steel mesh and phenolic resin. The iodine number was more increased over activation temperature of $450^{\circ}C$. Iodine number was 657 mg/g at activation temperature of $550^{\circ}C$, penolic resin concentration 20% and $ZnCl_2$ concentration 15%. Iodine number was 1359.4 mg/g when 10% cellulose added to these conditions.

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1920-1926
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• 2008

We investigated the C-H bond activation mechanism of aldimine by the [RhCl$(PPH_3)_3$] model catalyst using DFT B3LYP//SBKJC/6-31G*/6-31G on GAMESS. Due to their potential utility in organic synthesis, C-H bond activation is one of the most active research fields in organic and organometallic chemistry. C-H bond activation by a transition metal catalyst can be classified into two types of mechanisms: direct C-H bond cleavage by the metal catalyst or a multi-step mechanism via a tetrahedral transition state. There are three structural isomers of [RhCl$(PH_3)_2$] coordinated aldimine that differ in the position of chloride with respect to the molecular plane. By comparing activation energies of the overall reaction pathways that the three isomeric structures follow in each mechanism, we found that the C-H bond activation of aldimine by the [RhCl$(PH_3)_3$] catalyst occurs through the tetrahedral intermediate.

• Journal of the Korean Ceramic Society
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• v.28 no.4
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• pp.315-323
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• 1991

The preparation of zirconium carbide powders by the halogenide process of ZrCl4-C-Mg system (1:1:2, molar ratio) was studied between 300。 and 120$0^{\circ}C$ under Ar gas flow (200 mι/min). The formation mechanism and kinetics of zirconium carbide and characteristics of the synthesized powder were examined by TG-DTA, XRD, SEM and PSA. 1) The formation mechanism of zirconium carbide were as follows, above 30$0^{\circ}C$ ZrCl4(S)+Mg(s)longrightarrowZrCl2(s)+MgCl2(s) above 40$0^{\circ}C$ ZrCl2(S)+Mg(s)longrightarrowZr(s)+MgCl2(s) above 50$0^{\circ}C$ Zr(s)+C(s)longrightarrowZrC(s) 2) The apparent activation energy of the reduction-carbonization at temperature of 800$^{\circ}$to 100$0^{\circ}C$ was 11.9 kcal/mol. 3) The lattice parameter and the crystallite size of ZrC which was produced from the mixture powder of ZrCl4, C and Mg (1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were 4.700A and 180A, respectively. 4) The powders obtained from the mixture powder of ZrCl4, C and Mg(1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were agglomerate with the average size of about 13${\mu}{\textrm}{m}$ in SEM micrograph.

• Journal of the Korean institute of surface engineering
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• v.37 no.5
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• pp.301-306
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• 2004

Electric Conductivities of $LaCl_3$-LiCl binary melts have been measured by the Kohlausch bridge method over the range of their liquidus temperatures to about 1200 K. The electric conductivity increases with the content of LiCl for all over the composition range of binary melts. Composition dependence of the electric conductivity and molar conductivity for the binary melt shows a non-linear relation from the additivity line, and the deviations displays a maximum value at about 60 mol % LiCl. This suggest the existence of the complex ion of$ LaCl_{4}^{-}$ in the melt. Activation energy for electric conductivity of the binary melts decrease monotonously with increasing content of LiCl.l.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.426-432
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• 2013

The mechanisms concerning C-Cl activation of $CCl_4$ by $CHBr^{{\cdot}-}$ and $CBr{_2}^{{\cdot}-}$ have been comparatively investigated in theory. Optimized geometries and frequencies of all stationary points on PES are obtained at the BhandHLYP/aug-cc-pVTZ level of theory, and then the energy profiles are refined at the QCISD(T) method with the aug-cc-pVTZ basis by using the BhandHLYP/aug-cc-pVTZ optimized geometries. Our calculated findings suggest that in the title reactions the major mechanisms consist of both Cl-abstraction and $S_N2$ substitution reactions. Also, a succeeding pathway described by electron transfer was revealed before the initial Cl-abstraction products separate. Those are consistent with relevant experimental results.

• BMB Reports
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• v.55 no.6
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• pp.299-304
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• 2022

Chloride channel-5 (ClC-5), an important branch of the ClC family, is involved in the regulation of the proliferation and cell-fate of a variety of cells, including tumor cells. However, its function in cholangiocarcinoma (CCA) cells remains enigmatic. Here, we discovered that ClC-5 was up-regulated in CCA tissues and CCA cell lines, while ClC-5 silencing inhibited CCA cell proliferation and induced apoptosis. Further mechanism studies revealed that ClC-5 inhibition could inhibit Wnt/β-catenin signaling activity and further activate the mitochondria apoptotic pathway in CCA cells. Furthermore, rescuing Wnt/β-catenin signaling activation eliminated the anti-tumor function of ClC-5 knockdown. Together, our research findings illustrated that ClC-5 inhibition plays an anti-tumor role in CCA cells via inhibiting the activity of the Wnt/β-catenin pathway, which in turn activates the mitochondrial apoptotic pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.3
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• pp.231-241
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• 2001

The mammalian cortical collecting duct (CCD) plays a major role in regulating renal NaCl reabsorption, which is important in $Na^+$ and $Cl^-$ homeostasis. The M-1 cell line, derived from the mouse cortical collecting duct, has been used as a mammalian model of the study on the electrolytes transport in CCD. M-1 cells were grown on collagen-coated permeable support and short circuit current $(I_{sc})$ was measured. M-1 cells developed amiloride-sensitive current $5{\sim}7$ days after seeding. Apical and basolateral addition of ATP induced increase in $I_{sc}$ in M-1 cells, which was partly retained in $Na^+-free$ or $Cl^--free$ solution, indicating that ATP increased $Na^+$ absorption and $Cl^-$ secretion in M-1 cells. $Cl^-$ secretion was mediated by the activation of apical cystic fibrosis transmembrane regulator (CFTR) chloride channels and $Ca^{2+}-activated$ chloride channels, but $Na^+$ absorption was not mediated by activation of epithelal sodium channel (ENaC). ATP increased cAMP content in M-1 cells. The RT-PCR analysis demonstrated that M-1 cells express $P2Y_2,\;P2X_3\;and\;P2Y_4$ receptors. These results showed that ATP regulates $Na^+$ and $Cl^-$ transports via multiple P2 purinoceptors on the apical and basolateral membranes in M-1 cells.

• Journal of Preventive Medicine and Public Health
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• v.39 no.3
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• pp.199-204
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• 2006

Objectives: Mercury is a hazardous organ-specific environmental contaminant. It exists in a wide variety of physical and chemical states, each of which has unique characteristics for the target organ specificity. Exposure to mercury vapor and to organic mercury compounds specifically affects the CNS, while the kidney is the target organ for inorganic Hg compounds. Methods: In this study, mercury chloride $(HgCl_2)$ was studied in a renal derived cell system, i.e., the tubular epithelial Madin-Darby canine kidney (MDCK) cell line, which has specific sensitivity to the toxic effect of mercury. MDCK cells were cultured for 6-24 hr in vitro in various concentrations (0.1-100 M) of $HgCl_2$, and the markers of apoptosis or cell death were assayed, including DNA fragmentation, caspase-3 activity andwestern blotting of cytochrome c. The influence of the metal on cell proliferation and viability were evaluated by the conventional MTT test. Results: The cell viability was decreased in a time and concentration dependent fashion: decreases were noted at 6, 12 and 24 hr after $HgCl_2$, exposure. The increases of DNA fragmentation were also observed in the concentrations from 0.1 to 10 M of $HgCl_2$ at 6 hr after exposure. However, we could not observe DNA fragmentation in the concentrations more than 25 M because the cells rapidly proceeded to necrotic cell death. The activation of caspase-3 was also observed at 6 hr exposure in the $HgCl_2$ concentrations from 0.1 to 10 M. The release of cytochrome c from the mitochondria into the cytosol, which is an initiator of the activation of the caspase cascade, was also observed in the $HgCl_2-treated$ MDCK cells. Conclusions: These results suggest that the activation of caspase-3 was involved in $HgCl_2-induced$ apoptosis. The release of cytochrome c from the mitochondria into the cytosol was also observed in the $HgCl_2-treated$ MDCK cells. These findings indicate that in MDCK cells, $HgCl_2$ is a potent inducer of apoptosis via cytochrome c release from the mitochondria.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.65-69
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• 1997

[ $Mg_2SiO_4(La.Ho)$ ] thermoluminescent phosphor was made by putting the $MgCl_2.6H_2O$ and $SiO_2$ and by doping the rare earth element of $LaCl_3.7H_2O$ and $HoCl_3$. The heating rate is $10^{\circ}C/sec$ for the thermoluminescent phosphor. Two peaks are found in the measured $Mg_2SiO_4(La.Ho)$ Tl glow curve at $152^{\circ}C$ and $205^{\circ}C$ when the heating rate is $5^{\circ}C/sec$. The peak value at $205^{\circ}C$ is the most sensitive to X-ray among the glow peaks. The activation energy of the main peak has been estimated by the peak shape method. The estimated activation energies for Ho and La are $0.52{\sim}1.77\;eV$ respectively.