• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.453-460
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• 2013

Objective : There is a rich literature confirming the default mode network found compatible with task-induced deactivation regions in normal subjects, but few investigations of alterations of the motor deactivation in patients with intracranial lesions. Therefore, we hypothesized that an intracranial lesion results in abnormal changes in a task-induced deactivation region compared with default mode network, and these changes are associated with specific attributes of allocated regions. Methods : Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) during a motor task were obtained from 27 intracranial lesion patients (mean age, 57.3 years; range 15-78 years) who had various kinds of brain tumors. The BOLD fMRI data for each patient were evaluated to obtain activation or deactivation regions. The distinctive deactivation regions from intracranial lesion patients were evaluated by comparing to the literature reports. Results : There were additive deactivated regions according to intracranial lesions : fusiform gyrus in cavernous hemangioma; lateral occipital gyrus in meningioma; crus cerebri in hemangiopericytoma; globus pallidus, lateral occipital gyrus, caudate nucleus, fusiform gyrus, lingual gyrus, claustrum, substantia nigra, subthalamic nucleus in GBM; fusiform gyrus in metastatic brain tumors. Conclusion : There is increasing interest in human brain function using fMRI. The authors report the brain function migrations and changes that occur in patients with intracranial lesions.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.25-30
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• 2004

Rice seedlings were used to examine the effect of UV-B radiation on leaf elongation and development. Leaf elongation in both rice seedlings showed differently depending on each leaf age. UV-B radiation strongly reduced leaf elongation, 58-66% compared to without UV-B radiation, of two rice seedlings, therefore, those seedlings could not grow further. Both control and plants grown under UV-B regime showed a diurnial fluctuation in growth rate, showing maximum growth during the light period and minimum during the dark period. Leaf growth at the third leaf stage by UV-B treatment was considerably reduced by 1.7-fold than the control whereas at the fifth leaf stage was not changed. Hydrogen peroxide was considerably increased in the second phase of UV-B-induced response as catalase and peroxidase are deactivated with an increase of UV-B radiation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.981-984
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• 2011

A high-resolution numerical study is carried out to investigate the transient process of the combustion and the shock-train developments in an ethylene-fueled direct-connect dual-mode scramjet combustor. Following the fuel injection, air-throttling is applied at the expansion part of the combustor to provide mass addition to block the flow to subsonic speed. The ignition occurs several ms later when the fuel and air are mixed sufficiently. The pressure build up by the combustion leads to the shock train formation in the isolator section that advances to the exit of the intake nozzle. Then, the air-throttling is deactivated and the exhaust process begins and the situation before the air-throttling is restored. Present simulation shows the detailed processes in the dual-mode scramjet combustor for better understanding of the operation regimes and characteristics.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1077-1085
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• 2010

With an emphasis on its thermal behavior with different pHs and salts, the kinetic and thermodynamic parameters of the purified polygalacturonase (PG) from E. carotovora subsp. carotovora (Ecc) BR1 were studied, as the characterization of an enzyme is significant in the context of burgeoning biotechnological applications. The thermodynamic parameters for polygalacturonic acid hydrolysis by the purified PG were ${\Delta}H^*$=7.98 kJ/mol, ${\Delta}G^*$=68.86 kJ/mol, ${\Delta}S^*$=-194.48 J/mol/K, ${\Delta}G_{E-S}$=-1.04 kJ/mol, and ${\Delta}G_{E-T}$=-8.96 kJ/mol. In addition, its turnover number ($k_{cat}$) was 21/sec. The purified PG was stable within a temperature range of $20-50^{\circ}C$ and was deactivated at $60^{\circ}C$ and $70^{\circ}C$. The thermodynamic parameters (${\Delta}H^*$, ${\Delta}G^*$, ${\Delta}S^*$) for the irreversible inactivation of the PG at different temperatures ($30-60^{\circ}C$) were determined, where the effectiveness of various salts and different pHs (4-8) for the thermal stability of the PG were also characterized. The efficacy of various salts for the thermal stability of the PG was in the following order: $MgCl_2$ > $BaCl_2$ > KCl > $CaCl_2$ >NaCl. Therefore, the present work presents the biochemical, substrate hydrolysis thermodynamics and the thermal stabilization parameters of the PG from Ecc.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1923-1930
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• 2012

Mn-Cu catalysts were tested for selective catalytic reduction of NOx with NH3. Influence of initial reaction temperature was studied for NOx conversion in which reaction temperature was changed three patterns. NOx conversion of catalysts calcined at 200, 300 and $340^{\circ}C$ was measured during the changing temperature. Hydrogen conversion efficiency of calcined catalysts was also measured in the $H_2$-TPR system. The deactivation effect of $SO_2$ on catalyst was investigated with the on-off control of $SO_2$ supply. The catalyst which calcined above $340^{\circ}C$ was somewhat deactivated with thermal shock. The reason of deactivation was draw from the results of surface area and hydrogen conversion.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.249-256
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• 2011

In this study, the Ni-based catalysts for the production of synthetic natural gas were prepared by various preparation methods such as the co-precipitation, precipitation, impregnation and physical mixing methods. The ranges of the reaction conditions were the temperatures of 250~$350^{\circ}C$, $H_2$/CO mole ratio of 3.0, the pressures of 1 atm and the space velocity of 20000 $ml/g_{-cat{\cdot}}{\cdot}h$. It was found that the catalyst prepared by precipitation method had higher CO conversion than the catalyst prepared by co-precipitation method. While the catalyst prepared by precipitation method had the formation of NiO structure, the catalyst prepared by co-precipitation method had the formation of $NiAl_2O_4$ structure. It was confirmed that Ni-based catalyst prepared by the physical mixing method had the lowest CO conversion because it was deactivated by the production of $Ni_3C$ during the methanation. As a result, it was shown clearly that Ni-based catalysts prepared by impregnation method expressed the highest catalytic activity in CO methanation.

• Rapid Communication in Photoscience
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• v.4 no.2
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• pp.37-40
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• 2015

To examine the photosensitized biomolecules damaging activity, dimethoxyP(V)tetrakis(2-naphthyl)porphyrin (NP) and dimethoxyP(V)tetraphenylporphyrin (PP) were synthesized. The naphthyl moiety of NP hardly deactivated the photoexcited P(V)porphyrin ring in ethanol. In aqueous solution, the naphthyl moiety showed the quenching effect on the photoexcited porphyrin ring, possibly through electron transfer and self-quenching by a molecular association. Binding interaction between human serum albumin (HSA), a water soluble protein, and these porphyrins could be confirmed by the absorption spectral change. The apparent association constant of NP was larger than that of PP. It is explained by that more hydrophobic NP can easily bind into the hydrophobic pockets of HSA. The photoexcited PP effectively induced damage of the tryptophan residue of HSA, through electron transfer-mediated oxidation and singlet oxygen generation. NP also induced HSA damage during photo-irradiation and the contributions of the electron transfer and singlet oxygen mechanisms were speculated. The electron transfer-mediated mechanism to the photosensitized protein damage should be advantageous for photodynamic therapy in hypoxic condition. The quantum yield of the HSA photodamage by PP was significantly larger than that of NP. The quenching effect of the naphthyl moiety is considered to suppress the photosensitized protein damage. In conclusion, the naphthalene substitution to the P(V)porphyrins can enhance the binding interaction with hydrophobic biomacromolecules such as protein, however, this substitution may reduce the photodynamic effect of P(V)porphyrin ring in aqueous media.

• Journal of Photoscience
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• v.7 no.1
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• pp.1-4
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• 2000

The photosensory ciliates Blepharisma japonicum and Stentor coeruleus use the hypericin-derived pigments blepharismin and stentorin, respectively, as photoreceptor chromophores. Fluorescence quenching studies have shown that the first excited singlet state of hypericin and the purified chromophores blepharismin and stentorin can be deactivated by electron transfer to an acceptor molecule with a suitable reducing potential [1,2]. This paper reports the result of a series of photobehavioral experiments performed with the aim to ascertain if the same electron accepters which quench the photoreceptor pigment fluorescence in vitro may also compete with the native acceptor molecule in its natural physiological environment. Individual cell trajectories were examined before and after light stimulation, in the presence and in the absence of potential "in vivo" electron accepters, with a microvideo-recording apparatus. Our data, on Blepharisma cells, showed that as the negative reduction potential of the electron acceptor increases, a pronounced decrease in cell photoresponsiveness was detected. A dramatic effect on cell photoresponsiveness was noticed in the presence of 1,4-benzoquinone that has the lowest negative reduction potential. Such an effect on the percentage of photoreacting cells was moderate in the case of 1,4-naphthoquinone, with a relatively higher negative reduction potential. In the presence of benzophenone, which has the highest negative reduction potential, no significant effect on photoreacting cells was noticed. Our results can support the hypothesis that in the pigment granules such a light-induced charge transfer from excited blepharismin to a suitable electron acceptor triggers sensory transduction processes in B. japonicum.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.84-91
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• 2005

$TiO_2-catalyst$ suspensions work efficiently in Photocatalytic oxidation (PCO) for wastewater treatment. Nevertheless, once photocatalysis is completed, separation of the catalyst from solution becomes the main problem. The PCO of Cu(II)-EDTA was studied to determine the reusability of the titanium dioxide catalyst. Aqueous solutions of $10^{-4}M$ Cu(II)-EDTA were treated using illuminated $TiO_2$ particles at pH 6 in a circulating reactor. $TiO_2$ was reused in PCO system for treatment of Cu(II)-EDTA comparing two procedures: reuse of water and $TiO_2$ and reuse of the entire suspension after PCO of Cu(II)-EDTA. The results are as follows; (i) Photocatalytic efficiency worsens with successive runs when catalyst and water are reused without separation and filtration, whereas, when $TiO_2$ is separated from water, the reused $TiO_2$ is not deactivated. (ii) The $TiO_2$ mean recovery (%) with reused $TiO_2$ was 86.4%(1.73g/L). Although the mean initial degradation rate of Cu(II)-EDTA and Cu(II) was lower than that using fresh $TiO_2$, there was no significant change in the rate during the course of the three-trial experiment. It is suggested that Cu(II)-EDTA could be effectively treated using an recycling procedure of PCO and catalyst recovery. (iii) However, without $TiO_2$ separation, the loss of efficiency of the PCO in the use of water and $TiO_2$ due to Cu(II), DOC remained from previous degradation and Cu(II)-EDTA added to the same suspension was observed after 2 trials, and resulted in the inhibition of the Cu(II)-EDTA, Cu(II) and DOC destruction.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.843-850
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• 2011

This study investigated the effect of low dose ${\gamma}$-irradiation on the damage of the cell envelopes and antibiotic sensitivity profiles of Bacillus cereus, Escherichia coli, and Salmonella Typhimurium. The bacteria suspension in tryptic soy broth was exposed to the ${\gamma}$-irradiation doses of 0, 1, 1.5, 3, and 5 kGy, and then stored at $0^{\circ}C$ for 24 h. A viability test, an antimicrobial sensitivity profile, and an electron microscopy were performed to observe the effects due to ${\gamma}$-irradiation treatment. B. cereus could survive the ${\gamma}$-irradiation up to 5 kGy while E. coli and S. Typhimurium were all deactivated at 1.5 kGy and 5 kGy, respectively. At 5 kGy, the cell count of B. cereus was significantly reduced, and the survived bacteria cells retained their important features. There were no significant changes observed in the antimicrobial sensitivity profile (p>0.05) for the recovered bacteria after irradiation treatment. Low dose ${\gamma}$-irradiation below 3 kGy was found to be insufficient to achieve decontamination of B. cereus and S. Typhimurium. Cell envelope damage and deactivation of different bacteria did not occur in the same manner; thus, deferent doses of ${\gamma}$-irradiation may be required for deactivation of different bacteria.