• Archives of Pharmacal Research
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• v.16 no.3
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• pp.227-230
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• 1993

A new device to detect methamphetamine (MA), amphetamine(A) and its metabolites in urine was developed using the paper strip method and the test tube method of dry chemical reagents. The reagent containing tetrabromophenolphthalein ethyl ester (TBPE) and borax. For the TBPE paper strip method, a device was prepared with a window at each end of the reagent paper strip ; one window is for the sample application, and the other window is for the methylene chloride. The diffused sample from one window reacts with reagent in the paper and produces color at the point where it meets with methylene chloride which has diffused form the other side. A positive smaple produces as red-purple color and the negative sample a greenish color, with a detection limit of 5-10 ppm. The result can be obtained within one minute. For the TBPE test tube method which contains dry reagents, the detection limit is 5 ppm and the result can be obtaineed within 30 seconds, however the carry-on is not as convenient as the paper strip method. The performance of both methods were evlauated by comparing with the results of gas chromatography (GC) and fluorescence polarizaiton immunoassay (FPIA). The results were proven that both methods were useful as primary screening reagents to detect MA in urine and in dry powder.

• Journal of Environmental Science International
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• v.14 no.7
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• pp.683-689
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• 2005

The consecutive combination process of a biological process as the pre-treatment and a chemical process as the post-treatment is applied for the dyeing wastewater. The poor efficiency of biological treatment using pure oxygen makes the chemical treatment cost high. It is necessary to improve the efficiency of biological treatment in order to reduce the cost of chemical treatment. The purpose of this paper is to find the minimum dose of chemical reagent to fit the Discharged Water Quality Standards for the different biological treatment effluents. Results revealed that the minimum dosage of Fenton's reagent lead to save the cost of chemical treatment based on the guideline dose in the treatment plant. The possible maximum saving reagents was up to $70\%$ for the effluent of the pilot plant packed with the carrier imbedded microorganisms which were selected from the present treatment plant.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.51-59
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• 1996

The purpose of this study was to evaluate the partial oxidation of the biological treatment plant effluents using Fenton's reagent as a pretreatment step prior to a tertiary biological oxidation of these effluents. Fenton's reagent was evaluated as a pretreatment process for inhibitory or refractory organics. Based on the Fenton oxidation system, the petrochemical wastewater treatment plant effluent was shown to have significant improvement in toxicity after oxidation with hydrogen peroxide. For example, at ranee of 42 ∼ 184 mg/L COD of petrochemical plant effluents, the COD removal efficiencies were from 38.2% to 60.1% after reaction with hydrogen peroxide 200 mg/L and Fe2+ 100 mg/L and reaction time was 30 minutes. The total TOC reduction were about 15.8∼22.4% with same test condition and difference between the overall removal rate and BOD/COD ratio after Fenton's oxidation estabilished in the biodegradation and otherwise meets the discharge standard or reuse for cooling tower make-up water.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.3
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• pp.177-186
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• 2022

In this study, newly improved Ferron assay test haved on timed spectrometry was used for the determination of hyolrolytic Al species presented in PACl coagulant. The color development reagent ferron was prepared by using conventional method and two newly developed methods. Then the ferron assay test was used to compare and analyze the distribution of Al(III) hydrolyzed species presented in the prepared PACl and alum. The preparing method of reagent A required an aging period of 7 days by adding a hydroxylamine hydroxide and a 1,10-phenanthroline monohydrate reagent, whereas the preparing method of reagent B was used as a coloring agent immediately without aging time. The regression analysis between UV absorbance and Al concentrations of conventional method and newly developed method of ferron reagents in low-concentration aluminum solutions and high-concentration aluminum solutions, showed the correlation coefficients of 0.999 or higher, as showing high correlations of conventional method and newly developed method. Applying Ferron assay test, Al species in the PACls and alum were classified as Ala(monomeric Al), Alb (polymeric Al), and Alc (colloidal and precipitated Al). Distribution of Al(III) hydrolyzed species according to the preparation of ferron colorimetric reagents was similar.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.167-176
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• 1999

A new analytical procedure for the measurement of monomeric isocyanates and total isocyanate group in workplaces has been investigated. The method described herd involves derivatization of the isocyanate sample upon collection with the reagent 9-anthracenylmethyl 1-piperazinecarboxylate (PAC). Laboratory investigations have demonstrated that excess PAC reagent can be satisfactorily removed from PAC-derivatized monomeric isocyanates-a requirement for the success f the analytical procedure. After removal of excess PAC reagent, the PAC derivatives of butyl isocyanate, phenyl isocyanate, HDI, MDI, and TDI were reacted with sodium thiomethoxide to convert them all to 9-anthracenylmethyl methyl sulfide (AMMS). Total isocyanate group was determined by HPLC analysis and quantification of the single AMMS peak. This circumvents many of the disadvantages associated with current HPLC methods. There were no longer problems associated with quantifying late-eluting peaks and analysis times were very short. A single detector was used for quantification because a standard of the analyte existed and the retention time could be determined. Because all species were converted to a single analyte, the problem of variability of response factors among different species was averted. Finally, there were no complex chromatograms to interpret. Monomers of other individual species were measured by analysis of the sample before the individual species were converted to AMMS. The favorable performance of PAC warrants its further study as a reagent for the determination of total isocyanate group in air.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.63-68
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• 2018

Recently, safety accidents that occur in laboratories have occurred in various forms, so that a system that can reduce safety accidents in laboratories is required. The existing system identifies the danger situation according to the change of the temperature and the humidity, but the type of the danger situation is not known and the operation of the device is manually performed. Therefore, in this paper, we propose a system that identifies the danger situation of a reagent cabinet using multiple sensors and automatically operates the device. The internal environment of the reagent cabinet is measured in real time through the sensors and the sensor data is used to identify the danger situation. Also, when a danger situation is identified, the appropriate device is selected and operated automatically. In this way, identification of the danger situation of the reagent cabinet and automatic operation of the device will reduce the safety accidents occurring in the reagent cabinet.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.132-138
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• 1994

Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.382-388
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• 1989

The approximate rates and stoichiometry of the reaction of excess potassium tri-sec-butylborohydride ($K_s-Bu_3BH$) with selected organic compounds containing representative functional groups were determined under the standard conditions (0$^{\circ}C$, THF) in order to define the characteristics of the reagent for selective reductions. Primary alcohols evolve hydrogen in 1 h, but secondary and tertiary alcohols and amines are inert to this reagent. On the other hand, phenols and thiols evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to the corresponding alcohols. Reduction of norcamphor gives 99.3% endo- and 0.7% exo-isomer of norboneols. The reagent rapidly reduces cinnamaldehyde to the cinamyl alcohol stage and shows no further uptake of hydride. p-Benzoquinone takes up one hydride rapidly with 0.32 equiv hydrogen evolution and anthraquinone is cleanly reduced to the 9,10-dihydoxyanthracene stage. Carboxylic acids liberate hydrogen rapidly and quantitatively, however further reduction does not occur. Anhydrides utilize 2 equiv of hydride and acyl chlorides are reduced to the corresponding alcohols rapidly. Lactones are reduced to the diol stage rapidly, whereas esters are reduced moderately (3-6 h). Terminal epoxides are rapidly reduced to the more substituted alcohols, but internal epoxides are reduced slowly. Primary and tertiary amides are inert to this reagent and nitriles are reduced very slowly. 1-Nitropropane evolves hydrogen rapidly without reduction and nitrobenzene is reduced to the azoxybenzene stage, whereas azobenzene and azoxybenzene are inert. Cyclohexanone oxime evolves hydrogen without reduction. Phenyl isocyanate utilizes 1 equiv of hydride to proceed to formanilide stage. Pyridine and quinoline are reduced slowly, however pyridine N-oxide takes up 1.5 equiv of hydride in 1 hr. Disulfides are rapidly reduced to the thiol stage, whereas sulfide, sulfoxide, sulfonic acid and sulfone are practically inert to this reagent. Primary alkyl bromide and iodide are reduced rapidly, but primary alkyl chloride, cyclohexyl bromide and cyclohexyl tosylate are reduced slowly.

• Animal cells and systems
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• v.15 no.2
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• pp.131-138
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• 2011

Redox regulation is one of the ubiquitous mechanisms to modulate ion channels. We here investigated how 5,5'-dithio-bis (2-nitrobenzoic acid), a cysteine specific oxidizing reagent, modulates $Ca_v3.1$ and $Ca_v3.2$ T-type $Ca^{2+}$ channels expressed in Xenopus oocytes. Application of the reagent inhibited $Ca_v3.1$ and $Ca_v3.2$ currents in a dose-dependent manner. The oxidizing reagent (1 mM) reduced the peak amplitude of $Ca_v3.1$ and $Ca_v3.2$ currents by ~50% over 2-3 minutes and the decreased currents were fully recovered upon washout of it. The reagent slowed the activation and inactivation kinetics of $Ca_v3.1$, $Ca_v3.2$, and $Ca_v3.3$ channel currents. Notably, the reagent positively shifted both activation and steady-state inactivation curves of $Ca_v3.1$, while it did not those of $Ca_v3.2$. Utilizing chimeric channels from $Ca_v3.1$ and $Ca_v3.2$, we localized the domains III and IV of $Ca_v3.1$ responsible for the positive shifts of channel activation and steady-state inactivation. These findings provide hints relevant to the electrophysiological and molecular mechanisms accounting for the oxidative regulation of T-type channels.

• YAKHAK HOEJI
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• v.13 no.1
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• pp.33-37
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• 1969

A new organic reagent, 1-isonicotynyl-2-furfurylidene hydrazine synthesized from isonicotinic acid hydrazid and furfural, gives yellow liquid with cadmium (II). Cadmium complex of the reagent is soluble in water with yellow coloration. The complex has a maximum absorption at 363 m${\mu}$ and molar ratio of cadmium to reagent was estimated as 1:1 by continuous variation method and slope method. Molecular extinction coefficient and apparent formation constant of this complex was spectrophotometrically determined. K=4.48 $\times$ 10$^{3}$ (Babko's method) K=1.33 $\times$ 10$^{3}$ (Anderson's method)