• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.411-418
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• 1999

In this studies, the ability of chlorine and lactic acid to reduce bacterial population of the pathogenic microorganisms were examined on artificially inoculated chicken skin. About 10$^{5}$ cells of staphylococcus aureus, salmonella enteritidis, listeria monocytogenes and escherichia coli O157:H7 were inoculated in chicken skin. The contaminated samples were washed for 1 min with sodium hypochlorite solutions that contained 2, 5, 10, 20 and 50mg/$\ell$ available chlorine and counted number of the agents. Viable population were no significantly difference (p$\geq$0.05) between concentration of chlorine and strains of the pathogens. In the samples inoculated with pathogens were washed in 20mg/$\ell$ chlorine and then stored at $^5{\circ}C$ for up to 10 days, the initial counts of psychrotrophs and aerobic plate counts were 4.02 to 4.36 log cfu/$\textrm{cm}^2$ and increased slightly in course of time. But 10 days after, the pathogens were a little reduced from 3.66~4.91 log cfu/$\textrm{cm}^2$ to 2.54~4.66 log cfu/$\textrm{cm}^2$. In the case of washed skin with solution of 20mg/$\ell$ chlorine and 0.5% lactic acid then store at $^5{\circ}C$ for up to 10 days, population of psychrotrophs and aerobic plate counts on chicken skin were markedly reduced immediately after treatment, but the numbers of contaminants were slightly increased after 6 and 8 days. Specifically, numbers of St aureus, S enteritidis, L monocytogenes and E coli O157:H7 were reduced to 0.5, 0.4, 0.3 and 1.15 log cfu/$\textrm{cm}^2$ after 10 days of storage, respectively, on aerobic plate counts.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.289-299
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• 1996

It is necessary to measure the length of a root canal in order to attain a satisfactory prognosis after root canal therapy. There are several methods for determining root canal length, such as tactile sensation by the dental practitioner, the utilization of x-ray film, and electronic root canal measurement. Among these, the electrical measurement methods, in which the impedence between the oral mucous membrane and periodontal membrane is determined, have advantages of simplicity and accuracy. During root canal treatment, the root canal contains a solution of high electrical conductivity such as pus, blood, sodium hypochlorite and so on. Recently a new electronic root canal measurement device of frequency-dependent type has been developed, which is capable of measuring the length of root canal under moist conditions. Endex and Root ZX, which are frequency-dependent type, were evaluated for accuracy of measuring root canal length in vivo by stereomicroscope. The result were as follows ; 1. 82.5% of Endex and 87.5% of Root ZX measured in the range of ${\pm}0.5$ mm from the apical foramen and both showed 57.5 % in the range of 0.1 mm to 0.5 mm. 2. Endex showed significantly higher accuracy in vital teeth than nonvital teeth(p<0.05). But in case of Root ZX, there was no significant difference between vital and nonvital teeth. 3. As a result of this study, there was no significant difference in accuracy between Endex and Root ZX, and both devices showed file passes the apical foramen in more than half of the cases, and it is thought that this must be considered clinically.

• Membrane and Water Treatment
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• v.8 no.3
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• pp.225-244
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• 2017

A novel thin-film nanocomposite (TFN) reverse osmosis (RO)/non-woven fabric (NWF) membrane was prepared by adding zinc oxide (ZnO) nanospheres ($30{\pm}10nm$) during the interfacial polymerization process of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on self-made polysulfone (PSF) membrane/polyester (PET) non-woven fabric support. The improved performance of TFN RO membrane was verified in terms of water contact angle (WCA), water flux, salt rejection, antifouling properties and chlorine resistance. The results showed that the WCA value of TFN RO surface had a continuous decrease with the increasing of ZnO content in MPD aqueous solution. The water flux of composite TFN RO membranes acquired a remarkable increase with a stable high solute rejection (94.5 %) in $1g{\cdot}L^{-1}$ NaCl aqueous solution under the optimized addition amount of ZnO (1 wt%). The continuous testing of membrane separation performance after the immersion in sodium hypochlorite solution indicated that the introduction of ZnO nanospheres also dramatically enhanced the antifouling properties and the chlorine resistance of composite RO membranes.

• Membrane and Water Treatment
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• v.4 no.1
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• pp.27-51
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• 2013

During cleaning steps, ultrafiltration membranes are mechanically and chemically stressed. This may result in membrane degradations and failures. In this paper, polysulfone membranes were used to evaluate membrane deteriorations by commercial detergents in static conditions. Ageing of the membrane was simulated by immersing samples in solutions containing commercial detergents with various concentrations, temperatures and times defined by experimental designs. Indeed, an innovative approach in the chemical membranes ageing researches, based on methodological tools, was used in order to achieve significant ageing experiments without using an accelerated ageing protocol. The macroscopic changes were monitored by permeability measurements and mechanical strength tests coupled with a microscopic characterization by ATR-FTIR and HRSEM. The present work details results obtained for three commercial detergents: an alkaline, an acidic and an enzymatic detergent. It was found that the detergents used in the industrial advised conditions (concentration, temperature and time of contact) were not detrimental for membrane properties (permeability and elongation at break) and so for the quality of the produced water. Over the industrial cumulated time of contact, different ageing effects can be observed and compared with the ones induced by NaOCl.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Restorative Dentistry and Endodontics
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• v.28 no.3
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• pp.232-240
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• 2003

This study is to investigate the canal system in the mesiobuccal root of the maxillary first molar. 61 maxillary first molars were randomly selected. Serial transverse sections were made perpendicular to the long axis of the mesiobuccal root. Each section was placed in 3% sodium hypochlorite for 24 hours and rinsed in water and dried. The resected surface was stained with 2% methylene blue dye and examined with stereomicroscope. 1 Canal configuration analysis showed that 36.1% of the specimen classified as type I, 16.4% as type II , 37.7% as type III and 9.8% as type IV. 2. Type II canal was merged in one canal within 1 to 4mm of the apex. 40% of type II canal converged at 2mm of the apex. 3. Type IV canal was divided into two canal within 2 to 4mm of the apex. 66.6% of type IV canal branched off at 2mm of the apex. 4. None of the sections had more than two main root canal. 5. 48.4% of the sections in 3mm with two canals contained an isthmusand more than 70% with two canals has isthmus at 4 to 5mm sections. 63.9% of the mesiobuccal root of maxillary first molar had two canaland 76.5% of sections with two canals in 5 MM had an isthmus. Because of this complexity the clinician should always search for extra canal carefullyand root canal system, including an isthmus, should be cleaned and shaped completelyand obturated three dimensionally for successful endodontic treatment.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.23.1-23.12
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• 2020

Objectives: This study aimed to summarize the outcome of in vitro studies comparing the antibacterial effectiveness of QMix with other irrigants against Enterococcus faecalis. Materials and Methods: The research question was developed by using population, intervention, comparison, outcome, and study design framework. The literature search was performed using 3 electronic databases: PubMed, Scopus, and EBSCOhost until October 2019. The additional hand search was performed from the reference list of the eligible studies. The risk of bias of the studies was independently appraised using the revised Cochrane Risk of Bias tool (RoB 2.0). Results: Fourteen studies were included in this systematic review. The overall risk of bias for the selected studies was moderate. QMix was found to have a higher antimicrobial activity compared to 2% sodium hypochlorite (NaOCl), 17% ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine (CHX), mixture of tetracycline isonomer, an acid and a detergent (MTAD), 0.2% Cetrimide, SilverSol/H2O2, HYBENX, and grape seed extract (GSE). QMix had higher antibacterial efficacy compared to NaOCl, only when used for a longer time (10 minutes) and with higher volume (above 3 mL). Conclusions: QMix has higher antibacterial activity than 17% EDTA, 2% CHX, MTAD, 0.2% Cetrimide, SilverSol/H2O2, HYBENX, GSE and NaOCl with lower concentration. To improve the effectiveness, QMix is to use for a longer time and at a higher volume.

• Restorative Dentistry and Endodontics
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• v.45 no.3
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• pp.28.1-28.13
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• 2020

Objectives: To evaluate the outcome of in vitro studies comparing the effectiveness of QMix irrigant in removing the smear layer in the root canal system compared with other irrigants. Materials and Methods: The research question was developed by using Population, Intervention, Comparison, Outcome and Study design framework. Literature search was performed using 3 electronic databases PubMed, Scopus, and EBSCOhost until October 2019. Two reviewers were independently involved in the selection of the articles and data extraction process. Risk of bias of the studies was independently appraised using revised Cochrane Risk of Bias tool (RoB 2.0) based on 5 domains. Results: Thirteen studies fulfilled the selection criteria. The overall risk of bias was moderate. QMix was found to have better smear layer removal ability than mixture of tetracycline isonomer, an acid and a detergent (MTAD), sodium hypochlorite (NaOCl), and phytic acid. The efficacy was less effective than 7% maleic acid and 10% citric acid. No conclusive results could be drawn between QMix and 17% ethylenediaminetetraacetic acid due to conflicting results. QMix was more effective when used for 3 minutes than 1 minute. Conclusions: QMix has better smear layer removal ability compared to MTAD, NaOCl, Tubulicid Plus, and Phytic acid. In order to remove the smear layer more effectively with QMix, it is recommended to use it for a longer duration.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.379-390
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• 1998

In endodontic treatment, calcium hydroxide has been used as intracanal medicament. Although calcium hydroxide should be removed thoroughly before permanent root canal filling, no effective method for its removal has been reported. Because of irregularity of root canal walls, root curvatures and anatomic variations, it is insufficient to remove calcium hydroxide from the canal wall only by mechanical instrumentation Considering the chemical effects of irrigants on calcium hydroxide, $Ca^{++}$ dissolving effect from two calcium hydroxide products is investigated, using dis- tilled water, NaOCl, citric acid and EDTA. Vitapex$^{(R)}$ 0.1g and calcium hydroxide 0.03g were dissolved in distilled water, 5% NaOCl, 50% citric acid and 17% EDTA respectively, at 1, 3, 5, 10min. time interval. The solution was filtered using filter paper(pore size $5{\mu}m$) and $Ca^{++}$ concentration was determined by ion chromatography. The result were as follows : 1. Distilled water, NaOCl, citric acid and EDTA abstracted more $Ca^{++}$ from calcium hydroxide than Vitapex$^{(R)}$ except NaOCl 1, 5, 10 time interval. 2. EDTA and citric acid abstracted more $Ca^{++}$ from Vitapex$^{(R)}$ and calcium hydroxide than distilled water or NaOCl. The overall result support the view that water-based calcium hydroxide product is easily removed than oil-based calcium hydroxide product and EDTA, citric acid are more effective in $Ca^{++}$ elution than NaOCl or distilled water.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.105-113
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• 1995

Procedures for isolatin of chitin have been developed from crab(Chionoecetes opilio) shell waste with 26. 65% chitin on a dry basis. Optimal conditions for demineralization of crab shell were 1N HCl at ambient temperature for 30min with a solids to solbent ratio of 1 : 15(w/v). Optimal deproteinization involved treatment with 5% NaOH at $65^{\circ}C$ for 1 hr with a solids to solvent ratio of 1 : 15(w/v). Effective decoloration was achieved by bleaching with 0.32% sodium hypochlorite solution for 3min with a solids to solvent ratio of 1 : 10(w/v). Particular attentin was given to characterization of the physicochemical properties of the crab chitin. Chitins, from four different mesh sizes of crab shell, did not show significant differences in nitrogen and ash compositions. Bleaching decreased the viscosity of chitin but did not affect its solubility.