• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.44.1-44.9
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• 2020

Objectives: Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed. Materials and Methods: Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded. Results: The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA. Conclusions: IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.

• 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.

• 상하수도학회지
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• 제32권3호
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• pp.211-220
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• 2018

The water containing soluble manganese may cause problems such as discolored water, unpleasant taste, fouling or scaling of pipes in water distribution system, and so on. Conventional water treatment processes using sand filtration or sedimentation after oxidation, however, cannot often meet manganese standard for drinking water. Two types of oxidants, potassium permanganate ($KMnO_4$) and sodium hypochlorite (NaOCl), were utilized at the same time for manganese oxidation, and then the precipitated manganese oxides were removed by low pressure membrane filtration in this study. In batch experiments, the multiple injection of both oxidants showed more effective manganese removal than did the single injection using either of them. Moreover, the deterioration of manganese removal at low temperature was less serious for the multiple injection than that for the single injection. Manganese removal by the continuous system of oxidation by multiple injection combined with membrane filtration was higher than those by batch experiments at the same oxidation conditions. In addition, less membrane fouling was observed for membrane filtration with oxidation during continuous membrane filtration than membrane filtration without oxidation. These results indicate that the oxidation by multiple injection coupled with membrane filtration was efficient and applicable to actual water treatment for manganese removal.

• Journal of the Korean Wood Science and Technology
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• 제31권1호
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• pp.46-51
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• 2003

본 연구는 라디에타소나무 제재목의 균 변색을 제거하기 위한 표백처리의 사용 가능성을 조사하기 위하여 수행하였다. 염소계 표백제인 아염소산나트륨과 차아염소산나트륨은 표백조건(약제농도, 처리온도, 처리시간)의 조절에 따라 만족할만한 변색제거 효과를 얻을 수 있었다. 비염소계 표백제인 과산화수소는 표백조건의 조절만으로는 변색제거가 불가능하였으나 규산나트륨과 수산화나트륨을 활성제로 첨가하는 경우에는 염소계 표백제보다 탁월한 변색제거 효과를 나타내었다. 그러나 활성제 첨가에 따라 재색의 녹색화 문제가 발생하였는데, 앞으로 이러한 문제점을 해결하기 위한 연구가 진행되어야 할 것이다. 또한, 앞으로 본 연구를 통해 개발된 변색제거 방법의 현장 적용을 위한 후속 연구도 필요하다고 본다.

• Journal of the Korean Wood Science and Technology
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• 제27권4호
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• pp.65-71
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• 1999

This study was carried out to investigate the effect of xylanase pretreatment of the unbleached hardwood kraft pulp during the conventional Chlorine-Extraction- Hypochlorite (CEH) bleaching on pulp property. Optimum bleaching condition was evaluated by using Novozym produced from the fungus Humicola insolens. Also the effect of chelating agent prior to enzyme treatment was analyzed. The kappa number of enzymatic bleached pulp at the enzyme charge 10 IU/ml was slightly similar to that of bleached pulp without enzyme. By enzyme treatment, the chlorine charge in conventional CEH bleaching process of hardwood KP could be reduced by 17%, while no adverse effect on pulp yield and strength was. The optimum condition for enzyme pretreatment was 10 IU/ml xylanase charge, 3 to 4 hrs treatment, and 2% pulp consistency. In sugar composition in the enzyme pretreated pulp, arabinose and mannose were not much different, but more xylose was retained. This high content of hemicellulose in pulp seems to play an important role in pulp properties. The pulp pretreatment by chelating agent prior to enzyme treatment could improve the enzyme activity and enhance the bleaching effect at 0.2% diethylenetriamine pentaacetic acid (DTPA) charges.

• 한국물환경학회지
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• 제26권3호
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• pp.454-459
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• 2010

This study investigated the applicability of manganese coated media such as manganese coated sand (MCS), manganese coated sericite (MCSe) and manganese coated starfish material calcined at $550^{\circ}C$ (MCSf) to remove Mn(II) in synthetic wastewater. Manganese coated media prepared at different pH was applied in the treatment of soluble Mn(II) in batch and column experiments at various Mn(II) concentrations. The amount of Mn coated on three different media was approximately 800~1100 mg/kg. From the stability test, negligible dissolution of Mn was observed above pH 3.0. In batch test, more than 40% of Mn(II) was removed by all sand media at various manganese concentrations. In order to see the effect of additional oxidant for the removal of Mn(II), 4 mg/L of hypochlorite was added in Mn(II) solution during column experiment. Breakthrough of Mn(II) was greatly retarded in the presence of hypochlorite in all column reactors packed with different media. Among the manganese coated media, MCSf prepared at pH 4 indicated the highest removal capacity. The removal efficiency of Mn(II) was also increased in the multi-layer system (0.5 g of MCS, MCSe, and MCSf each).

• Environmental Engineering Research
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• 제24권2호
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• pp.298-308
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• 2019

This work deals with the membrane fouling mode and the unclogging in seawater ultrafiltration process. The identification of the fouling mechanism by modeling the experimental flux decline was performed using both the classical models of Hermia and the combined models of Bolton. The results show that Bolton models did not bring more precise information than the Hermia's and the flux decline can be described by one of the four Hermia's models since the backwash interval is ${\leq}60$ min. An experimental screening study has been then conducted to choose among 5 parameters (backwash interval, duration, pulses and the flow-rate or injected hypochlorite concentration) those that are the most influential on the fouling and the net water production. It has emerged that fouling is mainly affected by the backwash interval; its prolongation from 30 to 60 min engenders an increase in the reversible fouling and a decrease in the irreversible fouling. This later is also significantly reduced when the hypochlorite concentration increases from 4.5 to 10 ppm. Moreover, the net water production significantly increases with increasing the filtration duration up to 60 min and decreases with decreasing the backwash duration and backwash flow-rate from 10 to 40 s and from 15 to ${\geq}20L.min^{-1}$, respectively.

• Restorative Dentistry and Endodontics
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• 제17권1호
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• pp.104-114
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• 1992

The purpose of this study was to evaluate the shear bond strength of glass ionomer cement(Ketacfil, ESPE, Co.) against dentin surface which had been treated with surface conditioning agents(distilled water, 5% sodium hypochlorite solution, Ketac - conditioner, 40% polyacrylic acid). In this study, 60 human molars with sound and healthy crown portion which were previously extracted for orthodontic or periodontal problem. The dentin surfaces of these teeth were exposed with wet trimmer and polished with 150 - grit and 600 - grit silicon carbide paper and the teeth were divided into four groups(15 teeth per group) according to the following surface conditioning methods. Group I : Surface treatment with distilled water as control group. Group II : Surface conditioning with 5% sodium hypochlorite solution. Group III : Surface conditioning with Ketac conditioner. Group IV : Surface conditioning with 40% polyacrylic acid. The shear bond strengths were measured by Autograph(Shimatzu Co. Japan). The result of the evaluations were then subjected to statistical analysis using one - way analysis of variance and Duncan test and the results were as follows : 1. The shear bond strength accrding to the dentin surface conditioning conditions was highest in Ketac conditioner group, with measurements of $44.44{\pm}0.74(kg/cm^2)$ and lowest in the distilled water group, with measurements of $28.84{\pm}0.88(kg/cm^2)$. 2. Statistically significant differences were found between surface conditioning with 5% sodium hypochlorite solution group or Ketac conditioner group and distilled water group(P<0.01). 3. Also, statistically significant difference was found between surface conditioning with distilled water group and 40% polyacrylic acid group(P<0.05). 4. Overall difference in statistical significance between the groups was not found (P<0.05). 5. Fractured dentin surface treated with conditioning solutions showed cohesive fracture. 6. Distilled water group and 5% sodium hypochlorite solution group removed the smear layer less effectively. 7. Conditioning dentin with Ketac conditioner and 40% polyacrylic acid resulted in the removal of a significant amount of the smear layer without removing the tubular plugs and dissolving the peritubular dentin.

• 한국식품과학회지
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• 제39권4호
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• pp.419-424
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• 2007

생 홍고추를 열수, 오존수, 과산화수소와 차아염소산나트륨으로 살균 처리하여 적정 살균조건을 선정하고 선정된 조건에서 살균한 홍고추를 $-70^{\circ}C$로 냉동하여 $-30^{\circ}C$에서 30일 동안 저장한 후 품질변화를 측정하였다. $95^{\circ}C$에서 4분간 열수 처리하였을 때 E. coli와 coliform이 음성을 나타내었으며, 오존수 처리는 0.5 ppm에서 6분간 살균 처리하였을 때, 과산화수소는 2% 용액으로 12분간 살균처리로 음성을 나타냈다. 차아염소산나트륨 처리는 3% 용액으로 4분간 처리하였을 때 음성을 나타내었다. 선정된 각 최적조건에서 살균 처리하여 냉동저장 후 품질변화를 측정한 결과, 드립발생은 열수처리 시료가 15%로 가장 높았다. Ascorbic acid 함량은 오존수 처리 시료를 제외한 다른 처리구들은 대조구의 40%에도 미치지 못하는 함량을 나타내었으며, carotenoids 함량은 오존수 처리 시료가 124.16-182.87 mg%로 가장 적은 손실을 보였다. 관능검사 결과 오존수 처리 시료를 제외한 다른 처리구들은 내피의 탈색이 심하게 일어나고, 특히 열수처리의 경우 살균 처리에 의해 과육이 물러져서 외관이 심하게 손상되어 대조구와 유의적 차이를 나타내었다(p < 0.05). 따라서 시험한 살균방법 중에서 오존수처리가 가장 우수한 품질의 살균 생 홍고추를 생산하는데 적합한 방법으로 평가되었다.

• Journal of Species Research
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• 제6권1호
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• pp.68-75
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• 2017

We investigated the effects of sodium hypochlorite (NaOCl) and culture medium on embryo swelling and germination of Calanthe discolor Lindl., and established a method for determining the swelling and protocorm formation of C. discolor seeds via in vitro examination of immature seeds. Treatment of immature seeds with NaOCl greatly enhanced the extent of embryo swelling and protocorm formation of immature zygote embryos compared to seeds without NaOCl treatment. The effects of the culture media were also evaluated with regard to embryo swelling and protocorm formation of in vitro cultured seeds with and without NaOCl treatment. Additionally, the effects of white fluorescent light and red and blue LEDs lights on seedling growth in in vitro culture were examined. The most suitable condition for seedling growth after 12 weeks of culture was the red LEDs light with POM medium. These results show effective asymbiotic germination and growth of C. discolor.