• Journal of the Korean Chemical Society
• /
• v.6 no.1
• /
• pp.10-13
• /
• 1962

Titanium in solution of EDTA (Ethylenediaminetetraacetic acid) yield well-defined, reversible polarographic waves. In this report, a polarographic method for rapid determination of titanium in the Korean ilmenite was proposed, This polarographic method is based on the measurement of polarogram in the supporting electrolyte of EDTA. As the pH is increased the wave become more irreversible the diffusion current are diminished, and the half wave potential become more negative. In spite of the complication arising from numerous titanium species, in 0.2 M of EDTA, pH 6.3, the titanium waves are reproducible and analytically useful. In this medium titanium ion give well-defined reduction wave, and the half wave potential were -0.61V vs S.C.E. at pH 6.3. At the same time, the wave had a linear relationship between the concentration of titanium ion and the wave height. The Korean ilmenites were analyzed by this method and satisfactory results were obtained.

• Korean Journal of Microbiology
• /
• v.45 no.4
• /
• pp.377-384
• /
• 2009

Among 27 Bacillus sp. isolated from Meju, a traditional Korean soybean fermented food, a strain MJ-226 was selected due to its strong fibrinolytic activity, and it was identified to be Bacillus subtilis MJ-226 according to morphological and biochemical characterization and sugar utilization. The fibrinolytic enzyme of B. subtilis MJ-226 was maximally produced by cultivating in the Tryptic Soy Broth (TSB) for 24~26 h at $37^{\circ}C$, and the enzymes activity was promoted with adding glucose, fructose, peptone or yeast extract to TSB. The fibrinolytic enzyme was stable at the range of pH from 6.0 to 8.0, and between 35 and $40^{\circ}C$. Also, when the crude enzyme was exposed to various metal ions and chemical inhibitors for 12 h, the enzyme stability was maintained by $MnSO_4$, $CaCl_2$, KCl, and NaCl. However, the stability was destroyed by treatment with $CuSO_4$, $MgSO_4$, $ZnSO_4$, $FeSO_4$, and $BaCl_2$, and the enzyme was unstable in the presence of chemical inhibitors such as iodoacetic acid, leupeptin, phenylmethanesulphonyl fluoride (PMSF), sodium dodecyl sulfate (SDS), thiourea, trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) and ethylenediaminetetraacetic acid (EDTA).

• Restorative Dentistry and Endodontics
• /
• v.46 no.1
• /
• pp.11.1-11.11
• /
• 2021

Objectives: The aim of this study was to compare smear layer removal by conventional application (CA), passive ultrasonic irrigation (PUI), EasyClean (EC), and XP-Endo Finisher (XPF), using 17% ethylenediaminetetraacetic acid (EDTA) after chemomechanical preparation, as evaluated with scanning electron microscopy (SEM). Materials and Methods: Forty-five single-rooted human mandibular premolars were selected for this study. After chemomechanical preparation, the teeth were randomly divided into 5 groups according to the protocol for smear layer removal, as follows: G1 (control): CA of distilled water; G2 (CA): CA of 17% EDTA; G3 (PUI): 17% EDTA activated by PUI; G4 (EC): 17% EDTA activated by EC; and G5 (XPF): 17% EDTA activated by XPF. SEM images (×1,000) were obtained from each root third and scored by 3 examiners. Data were evaluated using the Kruskal-Wallis and Dunn tests (p < 0.05). Results: In the apical third, there were no statistically significant differences among the groups (p > 0.05). In the cervical and middle thirds, the experimental groups performed better than the control group (p < 0.05); however, G2 presented better results than G3, G4, and G5 (p < 0.05), which showed no differences among one another (p > 0.05). Conclusions: No irrigation method was able to completely remove the smear layer, especially in the apical third. Using CA for the chelating solution performed better than any form of activation.

• Restorative Dentistry and Endodontics
• /
• v.40 no.3
• /
• pp.216-222
• /
• 2015

Objectives: To evaluate the effects of copolymer of acrylic acid and maleic acid (Poly[AA-co-MA]) and calcium hypochlorite ($Ca(OCl)_2$) on root canal dentin using scanning electron microscope (SEM). Materials and Methods: Twenty-four single-rooted teeth were instrumented and the apical and coronal thirds of each root were removed, leaving the 5 mm middle thirds, which were then separated into two pieces longitudinally. The specimens were randomly divided into six groups and subjected to each irrigant for 5 min as follows: G1, $Ca(OCl)_2$; G2, Poly(AA-co-MA); G3, $Ca(OCl)_2$ + Poly(AA-co-MA); G4, sodium hypochlorite (NaOCl); G5, ethylenediaminetetraacetic acid (EDTA); G6, NaOCl+EDTA. The specimens were prepared for SEM evaluation. Smear layer, debris and erosion scores were recorded by two blinded examiners. One image from G3 was analyzed with energy dispersive spectroscopy (EDS) on suspicion of precipitate formation. Data were analyzed using the Kruskal-Wallis and Dunn tests. Results: G1 and G4 showed the presence of debris and smear layer and they were statistically different from G2, G3, G5 and G6 where debris and smear layer were totally removed (p < 0.05). In G1 and G4, erosion evaluation could not be done because of debris and smear layer. G2, G3 and G5 showed no erosion, and there was no significant difference between them. G6 showed severe erosion and was statistically different from G2, G3 and G5 (p < 0.05). EDS microanalysis showed the presence of Na, P, and Ca elements on the surface. Conclusions: Poly(AA-co-MA) is effective in removing the smear layer and debris without causing erosion either alone or with $Ca(OCl)_2$.

• Biomolecules & Therapeutics
• /
• v.10 no.2
• /
• pp.104-113
• /
• 2002

The effects of enzyme inhibitors and penetration enhancers on the permeation of leucine enkephalin (Leu-Enk) and its synthetic analog, [${D-ala}^2$]-leucine enkephalinamide (YAGFL) across the nasal, rectal and vaginal mucosae were evaluated. Enzyme inhibitors and penetration enhancers employed for Leu-Enk permeation study were amastatin(AM), thimerosal(TM) and ethylenediaminetetraacetic acid disodium salt(EDTA), and sodium taurodihydrofusidate (STDHF). Those for YAGFL permeation study were TM, benzalkonium chloride(BC) and EDTA, and STDHF, sodium deoxycholate(SDC), sodium glycholate(SGC), glycyrrhizic acid ammonium salt (GAA), L-$\alpha$-Iysophosphatidylcholine(LPC) and mixed micelle (MM, STDHF: linoleic acid = 15 mM : 5 mM). The addition of TM alone on the donor and receptor solutions for Leu-Enk permeation study across all the three kinds of mucosae failed to inhibit the degradation; it completely degraded in 6 hrs, and no permeation occurred. However, with addition of three kinds of inhibitors together, the fluxes across nasal, rectal and vaginal mucosae were $\20.7{pm}2.5$>/TEX>,$\0.3{pm}0.05$>/TEX> and $\1.4{pm}0.5$ $\mu$\mid$textrm{m}$/$\textrm{cm}^2$/hr, respectively. Moreover, the addition of STDHF in the presence of the above three inhibitors enhanced permeation across nasal, rectal and vaginal mucosae 1.3, 15 and 1.3 times, respectively. YhGFL also degraded in the donor and receptor solutions rapidly as time went. With mixed inhibitors of TM and EDTA, the percents of YAGFL remaining in the donor solutions facing nasal, rectal and vaginal mucosae were 69.7, 69.8 and 79.8%, respectively; the percent permeated increased to 10, 2.1 and 5.7%, respectively. The addition of STDHF in the presence of either BC/EDTA or TW/EDTA increased the permeation 2.2, 11.0 and 2.9 times, and 2.21, 14.0 and 2.7 times for nasal, rectal and vaginal mucosae, respectively. With SDC, SGC, GAA, LPC ud MM in the presence of TM/EDTA increased permeation; especially, they increased permeation across vaginal mucosae effectively, and the enhancement factors were 12.5, 7.6, 8.7, 5.7 and 5.5, respectively. The degradation extent of YAGFL was correlated with protein concentrations in the epidermal and serosal extracts. The flux of YAGFL across nasal mucosa increased dose-dependently.

• Economic and Environmental Geology
• /
• v.43 no.2
• /
• pp.123-136
• /
• 2010

In order to remediate heavy metal contaminated Nong island, Maehyang-ri shooting range soils through the batch reactor scale washing were evaluated. The experiment texture soil of N3 in the Nong island at north side incline was (g)mS containing 12.9% gravel, 47.0% sand, 35.1% silt and 5.0% clay. And the N3 soil area was contaminated with Cd($22.5\pm1.9$ ppm), Cu($35.5\pm4.0$ ppm), Pb($1,279.0\pm5.1$ ppm) and Zn($403.4\pm9.8$ ppm). The EDTA(ethylene diamine tetra acetic acid, $C_{10}H_{16}N_2O_8$) in the N3 soil was observed as most effective extractants among the 5 extractants(citric acid, EDTA, phosphoric acid, potassium phosphate and oxalic acid) tested. And chemical partitioning of heavy metals after washing N3 soil with EDTA was evaluated. Removal efficiency of residual fractions was higher than that of non-residual fractions. To choose EDTA extractant which is the most effective in soil washing technology using batch reactor process cleaning Pb and Zn contaminated sits; Pb and Zn removal rates were investigated 92.4%, 94.0% removal(1,000 mM, soil:solution=5, $20^{\circ}C$, 24 hour shaking, pH=2, 200 RPM), respectively. The results of the batch test showed that the removal efficiency curve was logarithmic in soil was removal. Thus, EDTA washing process can be applied to remediate the Pb and Zn contaminated soil used in this study.

• Korean Journal of Pharmacognosy
• /
• v.47 no.2
• /
• pp.122-127
• /
• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.4 no.2
• /
• pp.189-197
• /
• 1994

Analytic methods for Cr(VI) level in industrial hygienic field were suggested by the National Institute for Occupational Safety and Health(NIOSH method 7600, 7604). There were growing needs for measurement of Cr(III) and Cr(VI) levels simultaneously. Two analytical methods were suggested to determine Cr(III) and Cr(VI) levels simultaneously. The one is method by using reversed phase high peformance liquid chromatography(HPLC) and the other is by using ion exchange HPLC. The purpose of this work was to evaluate the usefulness of these two analytic methods. For the difference of ionic charges of Cr(III)-ethylendiamine tetraacetic acid(EDTA) chelate and $CrO_4{^-2}$, we could detect them simultaneously by ion exchange HPLC. Also, we attempted to determine the levels of Cr(III) and Cr(VI) chelated with sodium diethyldithiocarbamate(NaDDTC) by using reversed phase HPLC. The confirmation of Cr(III) and Cr(VI) were checked by fraction collector and nameless atomic absorption spectrometer. The optimal conditions for the formation of Cr(III)-EDTA chelate were two hours incubation period with pH 5. Cr(III)-EDTA and Cr(VI) in EDTA solution were successfully separated by anion exchange column using $Na_2CO_3/NaOH$ mixture as mobile phase. Peaks of Cr(III)-EDTA and Cr(VI) in EDTA were identified at 5 minutes and 7 minutes of retention time respectively by the ion exchange HPLC. The formation of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were twelve hours incubation period. Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates were separated by reversed phase column using methanol and water mixture as mobile phase. Peaks of Cr(VI)NaDDTC and Cr(III)-NaDDTC chelates were identified at 13 minutes and 26 minutes of retention time respectively by the reversed phase HPLC. Due to reduction of Cr(VI) to Cr(III), it seems to be not suitable for simultaneous determination of Cr(III)-NaDDTC and Cr(VI)-NaDDTC chelates by reversed phase HPLS. Simultaneos determination of Cr(III) and Cr(VI) by ion exchange HPLC was more accurate and simple method.

• Restorative Dentistry and Endodontics
• /
• v.40 no.4
• /
• pp.290-298
• /
• 2015

Objectives: Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide ($Ca[OH]_2$) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and $Ca(OH)_2$ application on the attachment and differentiation of dental pulp stem cells (DPSCs). Materials and Methods: DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL $Ca(OH)_2$, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction. Results: DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the $Ca(OH)_2$- and the EDTA-treated groups were significantly higher than those in the other groups. All $Ca(OH)_2$-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both $Ca(OH)_2$ and EDTA. Conclusions: The application of $Ca(OH)_2$ and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.

• Restorative Dentistry and Endodontics
• /
• v.40 no.2
• /
• pp.104-112
• /
• 2015

Objectives: This study was performed to investigate the effects of different intracanal medicaments on chemical structure and microhardness of dentin. Materials and Methods: Fifty human dentin discs were obtained from intact third molars and randomly assigned into two control groups and three treatment groups. The first control group received no treatment. The second control group (no medicament group) was irrigated with sodium hypochlorite (NaOCl), stored in humid environment for four weeks and then irrigated with ethylenediaminetetraacetic acid (EDTA). The three treatment groups were irrigated with NaOCl, treated for four weeks with either 1 g/mL triple antibiotic paste (TAP), 1 mg/mL methylcellulose-based triple antibiotic paste (DTAP), or calcium hydroxide [$Ca(OH)_2$] and finally irrigated with EDTA. After treatment, one half of each dentin disc was subjected to Vickers microhardness (n = 10 per group) and the other half was used to evaluate the chemical structure (phosphate/amide I ratio) of treated dentin utilizing attenuated total reflection Fourier transform infrared spectroscopy (n = 5 per group). One-way ANOVA followed by Fisher's least significant difference were used for statistical analyses. Results: Dentin discs treated with different intracanal medicaments and those treated with NaOCl + EDTA showed significant reduction in microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.05) compared to no treatment control dentin. Furthermore, dentin discs treated with TAP had significantly lower microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.0001) compared to all other groups. Conclusions: The use of DTAP or $Ca(OH)_2$ medicaments during endodontic regeneration may cause significantly less microhardness reduction and superficial demineralization of dentin compared to the use of TAP.