• 한국응용과학기술학회지
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• 제8권2호
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• pp.161-167
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• 1991

The kinetics of hydrolysis of cinnamenylisophorone derivatives (${rho}-H,\;{rho}-Br,\;P-Cl,\;{rho}-OCH_3$) was investigated using ultraviolet spectrophotometry in 20%(v/v) dicxane-$H_2O$ at 25$^{\circ}C$. A rate equation which can be applied over wide pH range (pH $1.0{\sim}13.0$) was obtained. In order to investigate the substituent effects on cinnarnenylisophorone derivatives, Hammett constant was plotted. As the result, the rate of hydrolysis of cinnamenylisophorone derivatives was facilitated by electron donating group. Final products of the hydrolysis were benzaldehyde and isophorone, From the measurement of reaction rate constant according to pH changes, substituent effect, and final products, it was found that the hydrolysis of cinnarnenylisophorone derivatives was initiated by the neutral $H_2O$ molecule which does not dissociated at below pH 9.0, and in the range of pH $9.0{\sim}11.0$ this reaction occurs by $H_2O$ or hydroxide ion competitively, but proceeded by the hydroxide ion above pH 11.0. On the basis of this kinetic study, the reaction mechanism of the hydrolysis of cinnamenylisophorone derivatives was proposed.

• ALGAE
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• 제18권3호
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• pp.191-197
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• 2003

Histones are important proteins that interact with the DNA double helix to form nucleosome. Two putative histone genes, GjH2A-1 and GjH2A-2 were isolated from a red alga Griffithsia japonica. The putative open reading frame of GjH2A-1 and GjH2A-2 shared high similarity with the previously reported amino acid sequences of histone H2As. They have a motif consisting of seven amino acids A-G-L-Q-F-P-V, which matches the histone H2A motif [AC]-G-L-x-F-P-V. Phylogenetic trees were constructed from amino acid sequences of 38 histone H2As. The histone H2As were divided into two groups: major H2As and H2A.F/Z variants. The major histone H2A group consisted of animals, fungi, plants + green algae, and red algae H2A subgroups. The animal histone H2A subgroup was divided into vertebrates, echinoderms, nematodes, insects, and segmented worms H2As. The putative red algal histone genes, GjH2A-1 and GjH2A-2, constituted an independent lineage. This is the first report on red algal histone genes.

• The Korean Journal of Physiology and Pharmacology
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• 제7권5호
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• pp.267-273
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• 2003

We have investigated the effect on inducing substate(s) of positively charged residues replaced in position 172 of the second transmembrane domain in murine inward rectifier potassium channels, formed by stable or transient transfection of Kir2.1 gene in MEL or CHO cells. Single channel recordings were obtained from either cell-attached patches or inside-out patches excised into solution containing 10 mM EDTA to rule out the effect of $Mg^{2+}$ on the channel gating. The substate(s) could be recorded with all mutants D172H, D172K and D172R. The unitary current-voltage (I-V) relation was not linear with D172H at $pH_i$ 6.3, whereas the unitary I-V relation was linear at $pH_i$ 8.0. The relative occupancy at $S_{LC}$ was increased from 0.018 at $pH_i$ 8.0 to 0.45 at $pH_i$ 5.5. In H-N dimer, that was increased from 0.016 at $pH_i$ 8.0 to 0.23 at $pH_i$ 5.5. The larger the size of the side chain or $pK_a$ with mutants (D172H, D172K and D172R), the more frequent the transitions between the fully open state and substate within an opening. The conductance of the substate also depended upon the pKa or the size of the side chain. The relative occupancy at substate $S_{LC}$ with monomer D172K (0.50) was less than that in K-H dimer (0.83). However, the relative occupancy at substate with D172R (0.79) was similar to that with R-N dimer (0.82). In the contrary to ROMK1, positive charge as well as negative charge in position 172 can induce the substate rather than block the pore in murine Kir2.1. The single channel properties of the mutant, that is, unitary I-V relation, the voltage dependence of the mean open time and relative occupancy of the substates and the increased latency to the first opening, explain the intrinsic gating observed in whole cell recordings.

• 한국식품과학회지
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• 제20권1호
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• pp.52-58
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• 1988

영지의 수용성추출물이 alcohol발효에 미치는 영향을 검토하기 위해 영지추출물을 0, 0.01, 0.1, 0.5, 1.0% 되게 첨가한 맥아즙에 S. cerevisiae를 접종하고 120시간 발효 ($15^{\circ}C$)과정중 S. cerevisiae의 생육도, pH의 변화 및 당 소비량, alcohol생성 등을 조사하였다. 영지추출물 첨가량이 증가 할수록 균체 증식은 현저하였고, 발효 120시간에서 0.1%, 0.5%, 1.0%구는 대조구보다 각각 1.2배, 1.5배, 1.9배 증가하였다. 발효액(120시간)의 당함량은 영지추출물 첨가량 순으로 낮았으나 pH 는 높았다. 발효 과정 중 총 alcohol 생성량은 영지추출물 첨가구가 모두 대조구보다 많았고 특히 고급 alcohol의 생성량은 120시간 발효후 1.0%구가 대조구에 비하여 약 1.8배 증가 하였다.

• 천문학논총
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• 제30권2호
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• pp.465-467
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• 2015

We presents a study of interactions between galaxies in the low-redshift group known as the NGC 4065 group. Imaging data were taken using the 2.4 meter telescope at the Thai National Observatory (TNO) for B, V and $R_c$ broadband filters and [$S\small{II}$] and Red-continuum narrowband filters. There are 21 galaxies in our sample. The results show that most early type galaxies (ETGs) with equivalent width EW($H{\alpha}$) < $10{\AA}$ are gas-deficient galaxies, while late type galaxies (LTGs) show more EW($H{\alpha}$) and are bluer than the ETGs. This means that star formation activity in the LTGs could be triggered by tidal interactions between galaxy members due to dense environmental effects in the compact group.

• 한국식품저장유통학회지
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• 제20권2호
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• pp.166-172
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• 2013

본 연구는 솔잎 유래의 phytoncide essential oil을 증류수에 희석한 것(1%, v/v, DP)과 식용 에탄올에 희석한 것(1%, v/v, EP), 증류수(DW) 및 식용 에탄올(EE)을 침지액으로 이용하였다. pH는 DW 처리구에서 가장 높고 EP 처리구에서 가장 낮았으며, 증류수보다는 에탄올 포함 처리구에서, 대조구보다는 phytoncide 성분이 포함된 처리구에서 낮은 pH인 것으로 나타났다. 적정산도는 EP 처리구가 가장 높고, DW 처리구가 가장 낮은 것으로 나타나 pH의 결과와 잘 일치하는 경향이었다. 총 가용성 고형분 함량은 1.60~2.23의 범위로, 에탄올이 포함된 EE 및 EP 처리구에서 유의적으로 높은 함량으로 나타났으며, 포장필름 내 기체조성 분석결과, EP 처리구가 modified atmosphere packaging (MAP)의 원리인 저산소 및 고이산화탄소 조건인 것으로 나타났다. 관능검사 결과, 외관, 색 및 갈변 정도에서 EP 처리구가 유의적으로 높은 점수를 얻었으며, DW 처리구가 가장 낮은 점수를 얻어 갈변 저해에 뛰어난 효과가 있음을 알 수 있었다. 총균수는 저장 중 꾸준히 증가하는 경향이었으며, EP 처리구가 가장 완만한 증가율을 보여 항갈변뿐만 아니라 항균에도 효과가 있음을 확인할 수 있었다. 이러한 결과들로 보아 EP 처리구는 갈변 저해 및 항균에도 효과가 뛰어나 품질 유지에 긍정적인 영향을 미치므로, 고품질 신선편이 양상추의 가공 및 유통에 있어 효과적인 방법으로 이용될 수 있을 것이라 기대된다.

• BMB Reports
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• 제28권3호
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• pp.204-209
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• 1995

The pH dependence of kinetic parameters in the amination direction of the aspartase from Hafnia alvei has been determined. The V/K for fumarate is bell shaped with pK values of 6.4 and 8.7. The maximum velocity for fumarate is also bell shaped with pK values of 7.2 and 9.1. The pH dependence of 1/K, for potassium (competitive inhibitor of ammonia) decreases at low pH with pK 7.6. Together with data [Yoon and Cook (1994) Korean J. Biochem. 27, 1-5] on the deamination direction of the aspartase, these results are consistent with two enzyme groups which are necessary for catalysis. An enzymatic group that must be deprotonated has been identified. Another enzyme group must be protonated for substrate binding. Both the general base and general acid group are in a protonation state opposite that in which they started when aspartate was bound. A proton is abstracted from C-3 of the monoanionic form of L-aspartate by an enzyme general base with, a pK of 6.3~6.6 in the absence and presence of $Mg^{2+}$ Ammonia is then expelled with the assistance of a general acid group giving $NH_{4+}$ as the product.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3696-3700
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• 2012

The colorimetric and fluorescent cyanide recognition properties of 2-[(9-ethyl-9H-carbazol-3-yl)methylene]-propanedinitrile (1) in $CH_3CN-H_2O$ (2/1, v/v, HEPES 10 mM, pH = 7.0) solution were evaluated. The optical recognition process of probe 1 exhibited high sensitivity and selectivity to cyanide ion with the detection limit of $2.04{\times}10^{-6}$ M and barely interfered by other coexisting anions. The sensing mechanism of probe 1 is speculated to undergo a nucleophilic addition of cyanide to dicyanovinyl group present in compound 1. The colorimetric and fluorescent dual-modal response to cyanide makes probe 1 has a potential utility in cyanide detection.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.576-581
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• 2014

This study used the heat conductive silicone rubber sample of 0.95 mm thickness to research the properties of current by changing voltage. When the 1, 10, 30, 60, and 90 minute have passed, the running current has been measured through the applied voltage range of 200 V~800 V on setting temperature of $110^{\circ}C{\sim}170^{\circ}C$. As the temperature increased in applied voltage of 800 V, so did the current value according to time in proportion to the increasing temperature. In an analysis of FT-IR (fourier transform infrared) spectrum, the hydroxyl radicals group(O-H) was created by effects of the hydrogen that methyl group is eliminated by addition of the cross-linking agent peroxide.

• Corrosion Science and Technology
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• 제2권5호
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• pp.219-224
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• 2003

Crevice corrosion of stainless steels in natural seawater was investigated for several post weld treatments; as-annealed, as-welded, pickled, and ground. The results confirmed the effect of the biofilm on the cathodic reaction leading to an ennoblement of the rest potential. The degree of ennoblement of corrosion potential depends on the surface finish. As-annealed and pickled samples show stable corrosion potential approaching to 200 ~ 300 mV (SCE) while as-welded and ground samples show the fluctuating corrosion potential. This points to a situation where there are conflicting effects determining the trend in free corrosion potential. Crevice corrosion initiation will tend to pull the free corrosion potential in the active direction, whereas the presence of biofilm will tend to ennoble corrosion potential. There was no visible attack on UNS S31803, S32550, and 2205W. Therefore, those stainless steel grades appeared to be resistant to crevice corrosion in natural seawater on condition of weld metal.