• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.288-292
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• 2006

Through statistically designed experiments, lysis agents were optimized to effectively disrupt bacterial cells in a microfluidic device. Most surfactants caused the efficient lysis of Gram-positive microbes, but not of Gram-negative bacteria. A Plackett-Burman design was used to select the components that increase the efficiency of the lysis of the Gram-negative bacteria Escherichia coli. Using this experimental design, both lysozyme and benzalkonium chloride were shown to significantly increase the cell lysis efficiency, and ATP was extracted in proportion to the lysis efficiency. Benzalkonium chloride affected the cell membrane physically, while lysozyme destroyed the cell wall, and the amount of ATP extracted increased through the synergistic interaction of these two components. The two-factor response-surface design method was used to determine the optimum concentrations of lysozyme and benzalkonium chloride, which were found to be 202 and 99 ppm, respectively. The lysis effect was further verified by microscopic observations in the microchannels. These results indicate that Gram-negative cells can be lysed efficiently in a microfluidic device, thereby allowing the rapid detection of bacterial cells using a bioluminescence-based assay of the released ATP.

• Journal of Environmental Health Sciences
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• v.19 no.2
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• pp.78-87
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• 1993

The accumulations of mercury, lactate dehydrogenase and antioxidant enzymes activities of which are glutathione peroxidase, catalase and superoxide dismutase, and pathological changes were investigated in liver and kidney of mice which were fed the water supplemented with two levels (0.5 mM and 1.0 mM) of mercury chloride (HgCl$_2$). During the mercury feeding, the weight gain of mice in experimental groups was less than that of control group mice, while no overt signs related to mercury toxicity were noted in any experimental groups. Mercury concentrations in liver and kidney increased significantly in the early period (1~2 weeks) after mercury administration, which were measured as high as 100 times in liver and kidney in comparison to those of the control groups, but there were relatively stable for the levels of accumulation in following periods. The lactate dehydrogenase activities in liver and kidney were relatively increased in the period of 2~3 weeks of mercury administration in the experimental groups, there were normal levels in other periods of administration without the dose-dependencies. The glutathione peroxidase activities were not affected by the dosages of mercury chloride and the duration of ingestion. But the catalase activities significantly increased in 2~3 weeks after ingestion, and the superoxide dismutase activities of kidney also showed a peak in 3 weeks of ingestion while this peak was not found in the results measured in liver tissues.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1134-1137
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• 2002

To investigate the neurotoxic effect of organic chloride on cultured mouse cerebral neurons, cytotoxic effect was measured by MTT assay after cultured cerebral neurons were incubated with various concentrations of methyl mercuric chloride(MMC) for 24 hours. The protective effect of Radix Polygoni Multiflori(RPM) on MMC-induced neurotoxicity was also examined in these cultures. MMC decreased cell viability of cultured mouse cerebral neurons remarkably in a dose- and time-dependent manners. In protective effect of RPM it was remarkably effective in blocking the neuroxicity induced by MMC. From aboved the results, it is suggested that MMC induce neurotoxicity, and the herba extract, RPM is very effective in preventing MMC-induced cytotoxicity on cultured mouse cerebral neurons.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.307-310
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• 2003

In order to analyze the concentration of cetylpyridinium chloride(CPC), a widely used cationic surfactant, we developed a simple and compact spectrometer, which consisted of a diode laser and a photodiode detector. Preliminary results are described here on the performances of the system in terms if the stability of output intensity, sensitivity, and reproducibility. Data on the comparisons of the system with the conventional UV-VIS spectrometer are also given. With the instrument, the concentration of CPC between 3${\times}$10$\^$-5/M and 1.1${\times}$ 10$\^$-4/M are calibrated as a correlation coefficient of 0.9635. The results shown here indicate a potential for developing a portable spectrometer useful for analyzing concentrations of CPC.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.383-389
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• 2018

Degradation of the insecticide O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate (chlorpyrifos) in aqueous solution was investigated using iron salts and potassium persulfate during ZVI treatment through a series of batch experiments. The degradation rate of chlorpyrifos increased with increases in the concentrations of iron salts and potassium persulfate in the aqueous system. Ferric chloride was found to be the most effective iron salt for the ZVI-mediated degradation of chlorpyrifos in aqueous solution. Further, the iron salts tested could be arranged in the following order in terms of their effectiveness: $FeCl_3$> $Fe_2(SO_4)_3$> $Fe(NO_3)_3$. The persulfate-ZVI system could significantly degrade chlorpyrifos present in the aqueous medium. This revealed that chlorpyrifos degradation by treatment with $Fe^0$ was promoted on adding ferric chloride and potassium persulfate. The kinetics of the degradation of chlorpyrifos by persulfate-amended $Fe^0$ was higher than that for iron-salt-amended $Fe^0$. This suggests that using a sequential $Fe^0$ reduction-ferric chloride or $Fe^0$ reduction-persulfate process may be an effective strategy to enhance the removal of chlorpyrifos in contaminated water.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.27-42
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• 2018

This study analyzed the utility of ammonium chloride ($NH_4Cl$) as a nitrogen source for methanotroph communities. When cultured in nitrate mineral salt (NMS) medium, the methanotroph community we identified four families, seven genera, and 16 type I and type II species of methanotrophs. Among species in the Methylobacter genus, Methylobacter marinus could be actively cultured in NMS medium without NaCl addition. Following the addition of 25 mM $NH_4Cl$, the numbers of the type I genera Methylomonas, Methylococcus, and Methylobacter were increased, whereas the numbers of the type II genera Methylocystis and Methylosinus were decreased after 5 days. In methanotroph communities, certain concentrations of $NH_4Cl$ affected methane consumption and growth of methanotrophs at the community level. $NH_4Cl$ caused a considerable decrease in the methane consumption rate and the expression of soluble methane monooxygenases (sMMOs) but did not inhibit the growth of Methylomonas methanica expressing sMMO. These results could be attributed to competitive antagonism of MMOs due to their direct involvement in ammonia oxidation.

• The Korean Journal of Pharmacology
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• v.2 no.1 s.2
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• pp.21-29
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• 1966

Dichloroisoproterenol(DCI) i; one of the well known ${\beta}$-adrenergic receptor blocking agents. According to Moran and Perkins, DCI has sympathomimetic like action in relatively low concentrations. Fleming and Hawkins confirmed that DCI acts upon the receptors concerned with positive chronotropic and inotropic actions in the heart. Vogins reported that DCI, in concentration of $5{\times}10^{-8}$ to $5{\times}10^{-6}g/ml$, had properties of sympathomimetic amine causing positive inotropic and chronotropic actions in normal rat atria. And James and Nadeau found that DCI had not only adrenergic blocking effect in moderate and higher concentrations, but it also blocked the effect on the sinus node by vagal stimulation and of directly administered acetylcholine in higher concentrations. As stated above by many authors, DCI has complicated actions according to its concentrations. Our aim at the present experiments was to study the effects of DCI to the action of ouabain and acetylcholine upon the excised rabbit atria, as well as to the action of barium chloride and acetylcholine upon the excised rabbit intestine. In addition, Pan ax Ginseng is widely used as tonics in oriental nations, its pharmacological action, however, has not been clearly established. So we atempted to investigate the effects of the water extract of Panax Ginseng to the action of ouabain and DCI upon both atria and intestine. The results obtained were as follows. 1) DCI has a negative inotropic effect on the excised rabbit atria at concentration of $10^{-5}$ and a positive inotropic effect at concentration of $10^{-6}$. 2) DCI (at concentration of $10^{-6}$) potentiates the positive inotropic effect of ouabain upon the excised rabbit atria. 3) DCI antagonizes the action of acetylcholine upon the excised rabbit atria. 4) The water extract of Panax Ginseng, at concentration of $10^{-3}$, decreases the contractile force of rabbit atria, and tends to slightly increase that of rabbit atria at $10^{-4}$. 5) The water extract of Panax Ginseng exhibits a synergistic action with ouabain on the contractile force of rabbit atria. 6) DCI, in concentrations of $10^{-7}{\sim}10^{-6}$, depresses the tone and amplitude of contraction of the excised rabbit intestine. The depression of the intestinal tone markedly appears in pretreatment with reserpine 2mg/kg 24 hours. 7) DCI antagonizes the contractile effect of barium chloride on the excised rabbit atria. 8) DCI has no significant influence on the action of acetylcholine upon the excised rabbit intestine. 9) The series of those evidences indicates that DCI has a sympathomimetic-like action and more over a relaxing action directly on the excised rabbit intestine. 10) The water extract of Panax Ginseng in concentrations of $10^{-4}{\sim}10^{-3}$, has transient depression of the intestinal tone, but later gradually recovers its normal motility: 11) The water extract of Panax Ginseng has a synergistic action with ouabain on the intestinal contractility.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.39-47
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• 2010

Using a conventional two-compartment cell with stirrers the separation of an aqueous solution of HCl-$NiCl_2$ by an anion-exchange membrane Neosepta-AFN was investigated. The dialysis process was characterized by the permeability coefficient of the membrane towards to $Cl^-$ ions. This quantity was determined by the numerical integration of equations, which describe the time dependence of the total concentration of $Cl^-$ ions in compartment initially filled with stripping agent (water), combined with an optimizing procedure. The analysis of the experimental results showed that this permeability coefficient is a satisfactory characteristic for the process studied. It can be graphically correlated with the initial acid and initial salt concentrations in the compartment initially filled with acid+salt mixture.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.697-702
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• 2001

Numerical simulations of 1,2 dichloroethane(EDC) pyrolysis are conducted to understand the process on the production of the vinyl chloride monomer(VCM) and by-products. A chemical kinetic mechanism is developed, the adopted scheme involving 44 gas-phase species and 260 elementary forward and backward reactions. Detailed sensitivity analyses and the rates of production analysis are performed on each of the reactions and the various species, respectively. The concentrations of EDC, VCM, and HCI predicted by this mechanism are in good agreement with those deduced from experiments of commercial and laboratory scale. The mechanism is found to accurately predict the VCM yield and the production of by-products by varying the ranges of pyrolysis temperature, residence time, and pressure which impact on the pyrolysis of 1,2 dichloroethane. The influence of reactions related to H atom on the relative sensitivity of EDC becomes important as the residence time increases. The pyrolysis of EDC mainly occurs through $C_{2}H_{4}Cl_{2}+Cl=CH_{2}ClCHCl$.

• Textile Coloration and Finishing
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• v.11 no.6
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• pp.36-42
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• 1999

The antimicrobial activities of the copolymer of N,N'-dimethyl- N,N'-diallyl ammonium chloride(DMDAAC) and diallyl amino(DA) were investigated. The copolymer of DMDAAC and DA was prepared by free radical Polymerization through an intra-intermolecular propagation mechanism ie, cyclopolymerization. The copolymer was, then, reacted with cyanuric chloride for reactivity with hydroxyl group of cellulose. Cotton fabrics were finished by synthesized polymer, and their antimicrobial activities and fastness to launderings were tested. Dichlorotriazinyl DMDAAC-DA copolymer has MIC value of 1ppm against S. aureus and 10ppm against K pneumoniae. The antimicrobial fastness of the finished cotton to launderings were good enough to show colony reduction above 70% against S. aureus and K pneumoniae after 50 repeated laundering in anionic commercial detergent. Optimum treatment concentrations of the polymer were 0.5% in cold pad-batch method, and 0.1% in pad-dry method.