• The Journal of Advanced Prosthodontics
• /
• 제4권1호
• /
• pp.24-29
• /
• 2012

PURPOSE. To compare the effect of sodium hypochlorite and microwave disinfection on the dimensional stability of denture bases without and with relining. MATERIALS AND METHODS. A brass die was prepared by simulating an edentulous maxillary arch. It was used to fabricate 1.5 mm and 3 mm of thickness denture bases (n = 40). The 1.5 mm of thickness-specimens (n = 20) were relined with 1.5 mm of autopolymerizing relining resin. Five holes were prepared over crest of ridge of brass die with intimately fitting stainless steel pins which were transferred to the intaglio surface of specimens during fabrication of denture bases. For calculation of dimensional changes in denture bases, differences between the baseline area before and after disinfection of the specimens were used. The denture bases without and with relining were divided into 2 groups (each n =20). Data were analyzed using student paired 't'and unpaired 't'test. RESULTS. Microwave disinfection produces significant shrinkage in both denture bases without relining (t =17.16; P<.001) and with relining (t = 14.9; P<.001). Denture bases without relining showed more shrinkage when compared with relined denture bases after microwave disinfection (t = 6.09; P<.001). The changes in dimensional stability after sodium hypochlorite disinfection were not significant for both denture bases without relining (t = 2.19; P=.056) and denture bases with relining (t = 2.17; P=.058). CONCLUSION. Microwave disinfection leads to increased shrinkage of denture bases without and with relining. Chemical disinfection with sodium hypochlorite seems to be a safer method of disinfection with regards to physical properties such as changes in dimensional stability.

• 한국수산과학회지
• /
• 제51권4호
• /
• pp.389-396
• /
• 2018

Marine pathogenic bacteria, such as Streptococcus parauberis, Edwardsiella tarda and Vibrio harveyi, can cause lethal infections in farmed fish, ozone and antibiotics, are employed to sterilize waters used for rearing fish to mitigate this threat. The most widely used method is treatment with sodium hypochlorite solution. However, the maintenance of a constant concentration of chlorine in rearing waters can be difficult. We investigated the potential of a mixed oxidant (MO) solution generated by electrolysis of sea water to improve water quality. We measured the survival rates of fish pathogenic bacteria exposed to different concentrations of MO (0.5, 1.0, 1.5 and 2.0 MO) and sodium hypochlorite (0.5, 1.0, 1.5 and 2.0 ppm) for various lengths of time (0, 5, 10, 15, 20, 25 and 30 min). We found a time-dependent decrease in the survival rates of the tested pathogenic microorganisms. The sterilization effect of the MO solution on pathogenic organisms was greater than that of sodium hypochlorite for gram-negative and gram-positive bacteria. We conclude that MO solution produced by electrolysis could be used to maintain a constant chlorine concentration in aquaculture systems.

• Journal of Photoscience
• /
• 제9권2호
• /
• pp.424-426
• /
• 2002

Recently, much attention has been paid to the physiological functions of flavonoids associated with their antioxidant properties. However, there was a lack of information on the molecular mechanism at which flavonoids play the antioxidative role. We have already studied on the oxidation of quercetin with hydrogen peroxide and sodium hypochlorite in alcoholic aqueous solution and determined the oxidation products. Through the structural analysis of the oxidation products, it was clarified that the hydroxyl group at C-3 in the C ring plays the important role in the antioxidative action of quercetin. Successively, rutin and (+)-catechin were oxidized with sodium hypochlorite and their mono- and di-chlorinated derivatives were obtained. These facts indicate that these flavonoids can directly scavenge hypochlorous acid and the active site in this scavenging reaction is not the hydroxyl group at C-3.

• 대한치과의사협회지
• /
• 제16권12호통권115호
• /
• pp.941-944
• /
• 1978

The author studied skin reactions and their incidences among 100 dental students and dental nurses to 2% Lidocaine HC1, 3% H₂O₂, Euginol, 5% Sodium Hypochlorite, Dycal and Adhesive plaster by means of Patch test. Following are the results of the study. 1. Eighty six cases out of 100 revealed slight response to 1 or 2 allergens. 2. 2% Lidocaine HC1 showed 1 case, 3% H₂O₂cases, Euginol 2 cases, 5% Sodium Hypochlorite 74 cases, Dycal 1 case Adhesive plaster 8 cases. 3. 5% Sodium Hypochlorite was the most influential to skin. 32 cases showed grade 1+, 20 cases showed grade 2++, 16 cases showed grade 3+++, 6 cases showed grade 4++++,

• ALGAE
• /
• 제29권4호
• /
• pp.311-319
• /
• 2014

The biocide sodium hypochlorite (NaOCl) is widely used for controlling algal growth, and this application can be extended to marine environments as well. This study evaluates the biocidal efficiency and cellular toxicity of NaOCl on the harmful dinoflagellate Cochlodinium polykrikoides, with emphasis on pigment production and antioxidant enzyme activity. The test organism showed dose-dependent decrease in growth rate on exposure to NaOCl, and the 72 h $EC_{50}$ was measured to be $0.584mg\;L^{-1}$. NaOCl significantly decreased pigment levels and chlorophyll autofluorescence intensity, indicating possible detrimental effects on the photosystem of C. polykrikoides. Moreover, it significantly increased the activities of antioxidant enzymes, suggesting the production of reactive oxygen species in the cells. These data indicate that NaOCl exerted deleterious effects on the photosynthetic machinery and induced oxidative damage in the dinoflagellate and this biocide could be effectively used for the control of algal blooms.

• Restorative Dentistry and Endodontics
• /
• 제8권1호
• /
• pp.77-87
• /
• 1982

The purpose of this study is to estimate the reaction of rat subcutaneous tissues following exposure to the various concentrations of formocresol (100, 50, 20%), eugenol (100, 75, 50%), and sodium hypochlorite. (5, 3.5, 0.5%) The results were as follows: 1. As the concentration of formocresol was decreased, the inflammatory reaction was decreased conspicuously. 2. The inflammatory reaction of 100% eugenol was appeared to be similar to that of 75% eugenol. The inflammatory reaction of 50% eugenol was decreased conspicuously. 3. No significant differences were found in inflammatory response between 3.5% and 5% sodium hypochlorite. 4. The inflammatory reaction of 0.5% sodium hypochlorite was mild and appeared to be similar to that of saline solution in 7 days.

• 한국환경보건학회지
• /
• 제35권1호
• /
• pp.58-63
• /
• 2009

This study investigated improvement to sludge dewaterability and coagulation for sewage treatment plant sludge by using sodium hypochlorite solution (NaOCl), ferric sulfate [$Fe_2(SO_4)_3$] and zeolite. The specific resistance to filtration(SRF), chloride, pH and turbidity were used to evaluate the sludge dewatering behaviors. The results of study were as follows: By varying the amount of NaOCl added the optimum result in terms of enhancement for pretreatment occurred when 34 mg/l of NaOCl was injected. When the total solids concentration of the sludge was 10,000 mg/l, the optimum ferric sulfate dosage for the sludge dewaterability was 150 mg/l and the corresponding SRF was $1.7{\times}10^7sec^2/g$. It was observed that injecting zeolite into sludge was effective in improving the dewaterability of sludge.

• Membrane and Water Treatment
• /
• 제10권5호
• /
• pp.381-385
• /
• 2019

Surface modification is very efficient and scalable approach to achieve improved membrane performance. We treated Reverse Osmosis Thin Film Composite (TFC RO) membrane with various concentrations of Polyethylene Glycol (PEG), a hydrophilic polymer after activation with sodium hypochlorite. This treatment resulted in an increment of the water flux by 43% and the salt rejection by 2.36% for the 3000 mg/l PEG-treated membrane. Further, these PEG-treated membranes were exposed to a mixture of 3000 mg/l PEG and 1000 mg/l sodium hypochlorite for 1 hour. Further modification of this membrane by PEG and sodium hypochlorite mixture increased the water permeance up to 133% when compared with the virgin TFC RO membrane. We characterized the treated membranes to understand the changes in wettability by contact angle analysis, changes in surface morphology and roughness by scanning electron microscope (SEM) and atomic force microscope (AFM) analysis.

• Restorative Dentistry and Endodontics
• /
• 제33권1호
• /
• pp.54-65
• /
• 2008

본 연구에서는 차아염소산나트륨 용액 및 고압증기멸균이 근관 치료용 Ni-Ti 파일의 주기적 피로 파절에 미치는 영향을 알아보고자 하였다. 파일 첨단 크기가 #30이고 .06 taper를 가지는 Hero $642^{(R)}$와 $K3^{(R)}$파일 70개를 10개씩 7개의 군으로 나누었으며, 6% 차아염소산나트륨 용액에 15분 (N15군), 30분 (N30군), 고압증기멸균은 $121\;^{\circ}C$의 온도, 0.12 MPa의 압력에서 20분간 시행하는 것을 일 회로 하여 5회 (H5군), 10회 (H10), 고압증기멸균 5회 후 차아염소산나트륨 용액 15분(H5N15), 고압증기멸균 10회 후 차아염소산나트륨 용액 30분 (H10N30) 처리 후 주기적 피로 파절 실험을 수행하여 파일이 파절될 때까지의 시간을 초 단위로 측정하였다. 대조군은 전처리를 하지 않고 주기적 피로 파절을 시행하였다. 95%의 신뢰도로 one-way analysis of varience를 이용하여 통계 처리하였으며, 다중 비교는 Tukey방법으로 분석하였다. 파일의 표면을 주사전자현미경으로 관찰하였다. 주기적 피로 파절에 소요된 시간은 Hero $642^{(R)}$는 각 군별로 유의할 만한 차이가 없었으며, $K3^{(R)}$는 N15, N30, H5N15군에서 대조군에 비해 짧은 시간이 소요된 것으로 나타났다 (p < 0.05). 주사전자 현미경에서 관찰했을 때 Hero $642^{(R)}$와 $K3^{(R)}$모두 N15, N30군에서 파일의 표면과 날이 부식이 되어 대조군에서 관찰된 일정 방향으로 배열된 정형화된 예리한 빗살무의가 부분적으로 파괴된 형태가 관찰되었으며, N15군에 비해 N30군에서 파일의 형태가 파괴된 양상이 뚜렷했으며, Hero $642^{(R)}$보다 $K3^{(R)}$가 심하게 부식된 양상이었다. H5군과 H10군에서는 $K3^{(R)}$ 파일은 날 부분이 무디어진 양상을 보였고, Hero $642^{(R)}$는 형태 파괴가 뚜렷하지 않았으나 H10군에서 표면의 빗살무늬가 약간 무디어진 양상을 보였다. H5N15군과 H10N30군에서는 그다지 뚜렷한 형태변화는 없었다. 본 연구 결과 $K3^{(R)}$파일을 사용 시에는 가능한 한 차아염소산나트륨에 적은 시간 노출시키는 것이 파일의 부식으로 인한 형태의 손상을 방지할 수 있고, 주기적 피로 파절에 걸리는 시간도 감소시킬 수 있을 것이다.

• 한국균학회지
• /
• 제22권2호
• /
• pp.190-195
• /
• 1994

느타리버섯의 재배에서 크게 문제되는 세균성 갈반병(병원균: Pseudomonas agarici)의 방제를 위하여 살균 및 표백제로 사용되면서 식품오염이 비교적 문제시되지 않는 SHC 용액을 버섯에 직접 살포할 수 있는 방안을 검토하였던 바 다음과 같은 결론을 얻었다. 1. p. agarici에 대한 SHC의 최소저지 농도는 80ppm이었으며 매일 100ppm 미만의 용액 살포는 버섯균사의 생장을 저해하였으나 곧 바로 회복되어 가시적인 피해는 나타나지 않았다. 2. 포장시험결과 40-50 ppm의 SHC 처리는 세균성 갈반병을 효과적으로 방지하고 버섯의 생육에 거의 지장을 초래하지 않아 건전자실체 수를 증가시킬 수 있었다. 3. SHC의 농도가 67ppm으로 살포되었을 경우에는 수량이 감소하고 2주기 재배시에 육질의 경도가 떨어졌으며, 자실체의 색깔이 연한 갈색이나 짙은 회색으로 변하고 갓의 모양이 약간 굴곡지고 대가 신장하는 경향을 보였다. 4. 본 실험 결과 주기적인 SHC 살포는 느타리버섯의 품질을 저하시키지 않고 느타리버섯의 세균성 갈반병의 방제를 하는데 있어서 권장할 만한 방법으로 사료된다.