• Restorative Dentistry and Endodontics
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• 제33권4호
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• pp.397-404
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• 2008

본 연구의 목적은 최종 근관세척제로서의 MTAD, EDTA 그리고 차아염소산 나트륨 용액이 충전된 근관의 세균 (Enterococcus faecalis) 미세누출에 미치는 영향을 평가하기 위한 것이다. 40개의 발치된 사람의 대구치를 양성대조군 (1군 : n = 5), 음성대조군 (2군 : n = 5), 그리고 실험군 (3, 4, 5군 : n = 10)으로 각각 무작위 배정하였다. 3군에서는 근관형성시 차아염소산 나트륨만 사용하여 근관세척을 시행하였으며, 4군 및 5군에서는 차아염소산 나트륨과 함께 EDTA와 MTAD를 각각 최종 근관세척제로 사용하였다. 실험군 및 대조군의 치아들은 .06 taper를 가지는 40번 profile을 master apical file로 근관형성을 시행하였으며 gutta-percha와 AH-26 근관봉함제로 근관충전하였다. 각 치아의 치관부는 Enterococcus faecalis를 함유한 BHI 배지와 접촉되도록 하였고 치근 끝부분은 멸균된 배양액에 위치되도록 하였다. 각각의 치아는 anaerobic chamber내에 위치되었으며 180일 동안 혼탁도를 관찰하였다. 통계처리는 95% 신뢰수준에서 Fiher's exact test를 사용하였다. 180일의 관찰기간이 경과된 후, 3, 4, 5 군은 각각 7, 4, 5 개의 치아에서 미세누출이 일어났으며 이 차이는 통계적으로 유의성이 없었다.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.211-217
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• 2022

차아염소산나트륨(NaClO)은 병원 및 식품산업 분야에서 널리 사용되는 소독제로 세균, 곰팡이, 바이러스에 대해서도 항균 활성이 있다. 차아염소산나트륨의 항균 활성은 용액의 pH에 의해 조절되는 안정적인 HClO 농도의 유지에 있다. 차아염소산(HClO)은 화학적으로 중성이므로 세균의 막에 쉽게 침투할 수 있으며 차아염소산나트륨의 항균 활성은 차아염소산염 이온(ClO^-)보다는 용액 내 HClO 농도에 의존하리라 사료된다. 본 연구에서 pH 조절에 따른 차아염소산나트륨의 항균 활성을 time kill test와 차아염소산나트륨 처리 전후의 활성산소종(ROS) 및 ATP 농도 변화로 조사하였다. 또한 전계방출형 주사 전자 현미경(FE-SEM)을 통하여 세포벽의 파괴정도를 확인하였다. pH 5 조건에서 5 ppm 차아염소산나트륨은 Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) 균에 대하여 99.9%의 항균 활성을 나타내었고, ROS 생성량은 pH 7 조건보다 48% 증가하였다. 또한, pH 5 조건의 차아염소산나트륨에 노출된 E. coli와 S. aureus의 ATP 농도가 각각 94%와 91% 감소하였다. FE-SEM 결과, pH 5 조건에 노출된 균의 세포벽이 파괴된 것을 확인하였다. 본 연구결과를 종합해보면, pH를 조절하는 것 만으로 5 ppm 농도의 차아염소산나트륨의 항균 활성을 향상시킬 수 있음을 시사한다.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1251-1252
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• 2004

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.141.1-141.1
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• 2003

Paraoxonase, an antioxidant enzyme, exclusively located on HDL is well known for both hydrolysis of organophosphate and prevention against LDL oxidation. It have been reported that PON1 decrease its activity under oxidative stress and that PON1 activity is lower in subject with higher vulnerability to organophosphate poisoning. The aim of our study is to examine the effect of oxidative system on paraoxon-hydrolzing activity and to elucidate the plausible mechanisms responsible for the decline of HDL-asscociated PON1 activity in vivo system. (omitted)

• Parasites, Hosts and Diseases
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• 제54권1호
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• pp.103-107
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• 2016

The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at $25^{\circ}C$ in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely.

• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.104-108
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• 2014

Objectives: To evaluate the effect of passive ultrasonic agitation on the cleaning capacity of a hybrid instrumentation technique. Materials and Methods: Twenty mandibular incisors with mesiodistal-flattened root shape had their crowns sectioned at 1 mm from the cementoenamel junction. Instrumentation was initiated by catheterization with K-type files (Denstply Maillefer) #10, #15, and #20 at 3 mm from the working length. Cervical preparation was performed with Largo bur #1 (Dentsply Maillefer) followed by apical instrumentation with K-type files #15, #20 and #25, and finishing with ProTaper F2 file (Denstply Maillefer). All files were used up to the working length under irrigation with 1 mL of 2.5% sodium hypochlorite (Biodyn$\hat{a}$mica) at each instrument change. At the end of instrumentation, the roots were randomly separated into 2 groups (n = 10). All specimens received final irrigation with 1 mL of 2.5% sodium hypochlorite. The solution remained in the root canals in Group 1 for one minute; and ultrasonic agitation was performed in Group 2 for one minute using a straight tip inserted at 1 mm from working length. The specimens were processed histologically and the sections were analyzed under optic microscope (x64) to quantify debris present in the root canal. Results: The samples submitted to ultrasonic agitation (Group 2) presented significant decrease in the amount of debris in comparison with those of Group 1 (p < 0.05). Conclusions: The hybrid instrumentation technique associated with passive ultrasonic agitation promoted greater debris removal in the apical third of the root canals.

• Asian-Australasian Journal of Animal Sciences
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• 제16권10호
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• pp.1438-1442
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• 2003

A method for the determination of nitrogen in ruminant feedstuffs, products and excreta (e.g. milk and urine) using a spectrophotometer is developed, where samples processed for P determination are also used to determine N. Samples are digested with sulphuric acid and subsequently with hydrogen peroxide in Kjeldahl tubes. Digested solutions along with phenol and buffered alkaline hypochlorite reagents are incubated in a water bath at $37^{\circ}C$ for 30 min and presented in the spectrophotometer. The spectrophotometer set at 625 nm measures the concentration of N of each sample. Nitrogen in 261 of the samples was also determined by the classical Kjeldahl method in order to develop a relationship between N determined by the Kjeldahl method (Y) and the colorimetric method (X). The mean value of Y was as high as that of X (0.92 vs. 0.96; p>0.05). The colorimetric method predicted Kjeldahl N highly significantly (Y=0.985X-0.024, $R^2=0.993$, p<0.001; or more simply Y=0.974X, $R^2=0.993$, p<0.001). An analysis of regression found no difference (p>0.05; both t-test and F-test) between colorimetric (0.96% N) and adjusted (0.96% N) N. In comparison with the Kjeldahl method, the analytical capacity of N by colorimetric method increases greatly, where 200-300 determinations of N are possible in a working day. In addition, the system provides an opportunity to use not only the same digested solution for both N and P determination of a particular sample, but also uses the same spectrophotometer to assay both N and P. Therefore, the system may be attractive in situations where both elements of a sample are to be determined. In conclusion, the speed of N determination, low cost, efficient use of labour, time and reagents, fewer items of equipment, and the reduction of environmental pollution by reducing effluent and toxic elements are the advantages of this method of N determination.

• Restorative Dentistry and Endodontics
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• 제42권4호
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• pp.264-272
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• 2017

Objectives: Literature has shown that micro-organisms contaminate gutta percha (GP) during storage and manipulation. Till date herbal extracts are not explored as an alternative medicament for pre-operative chairside disinfection of GP cones. The purpose of our study was to evaluate the antimicrobial activity and efficacy of lemon grass oil (LG), basil oil (BO), and obicure tea extract (OT) in disinfecting GP cones before obturation. Materials and Methods: Agar diffusion method was used to evaluate the antimicrobial efficacy of LG, BO, OT, and sodium hypochlorite (control) against common contaminants, namely, Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. One hundred and twenty GP cones were contaminated and cut into 2. First half was placed in the broth and incubated; whereas the second was treated with herbal extracts for 1 minute and then incubated for 24 hours in the broth. Any inhibition in bacterial growth was noted with presence/absence of turbidity. Two-way analysis of variance and ${\chi}^2$ test were used to assess the effectiveness of herbal extracts to decontaminate GP. Results: LG showed the highest inhibition zones ($29.9{\pm}6.9mm$) for all tested organisms, followed by OT extract ($16.3{\pm}1.8mm$), sodium hypochlorite ($16.0{\pm}1.6mm$), and BO ($14.5{\pm}5.3mm$). Statistically significant difference was observed between LG and other herbal extracts (p < 0.05). Conclusions: All extracts proved to be potential rapid chairside disinfectants of GP cones with LG showing the highest antimicrobial activity.

• 한국환경보건학회지
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• 제44권3호
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• pp.244-249
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• 2018

Objectives: The purpose of this study was the investigation of bromide and bromate in drinking water of water supply plants, mineral springs and small water supply system located in northern area of Gyeonggi province. Methods: Analytical method was based on EPA 326.0 to use Postcolumn reaction (PCR). The instrument was 887 professional UV/VIS detector IC manufactured in Metrohm. Results: Bromate was detected at $0.5{\sim}2.4{\mu}g/L$ in tap water from 5 water supply plants. These plants were used as disinfection method for sodium hypochlorite and on-site chlorine that causes generate bromate as a by products even if not used ozone. Conclusions: The bromate was detected up to $2.5{\mu}g/Lin$ drinking water in northern Gyeonggi area that showed within $10{\mu}g/L$ for standard of tap water. However, the continuous monitoring of bromate is necessary in drinking water.

• Food Science and Biotechnology
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• 제17권5호
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• pp.971-975
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• 2008

This study was to examine the potential disinfection efficiencies of 10 compounds by determining their antimicrobial capacity and ichthyotoxicity. Antimicrobial effects against Vibrio sp., Edwadsiella tarda, Streptococcus sp., and Staphylococcus sp. were tested using 10 different disinfectants; hydrogen peroxide, sodium hypochlorite, chlorine dioxide, povidon iodine, formaldehyde, glutaraldehyde, quaternary ammonium compounds (QACs), didecyl dimethyl ammonium chloride (DDAC), ortho-dichlorobenzen, and copper sulfate. Chlorine dioxide ($ClO_2$) containing 5% $ClO_2$ and copper sulfate had no effects on bactericidal activity, while the other disinfectants resulted in 99.99% bactericidal activity against 4 strains of fish pathogenic bacteria. The ichthyotoxicity of the 10 disinfectants was investigated using 3 kinds of fish species; flounder (Paralichthys olivaceus), rockfish (Sebastes pachycephalus), and black sea bream (Acanthopagrus schlegelii). Median lethal concentration ($LC_{50}$) values of the 10 disinfectants were estimated to determine toxicity ranges of the doses within 24 hr. Among test disinfectant solutions, hydrogen peroxide showed the highest $LC_50$ in flounder (201.3), rockfish (269.7), and black sea bream (139.3 ppm). DDAC revealed the lowest $LC_{50}$ in flounder (2.1), rockfish (1.0), and black sea bream (1.5 ppm). These results suggest that DDAC, quaternary ammonium compounds, glutaraldehyde, and sodium hypochlorite are effective disinfectants for fish and bacterial species examined in this study.