• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.67-78
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• 1992

The application of white-rot fungi to pulping and bleaching processes has been studied at the Wood Chemistry Laboratory in Kyushu University, cooperatively with the Biotechnology Laboratory of Kobe Steel, Ltd. Some successful results of the studies for a biomechanical pulping process, biobleaching of hardwood and softwood kraft pulp, as well as chlorine free biobleaching of oxygen-prebleached hardwood kraft pulp are dealt with. Biological treatment of the pulp bleaching effluent is also described.

• 펄프종이기술
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• 제33권2호
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• pp.68-73
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• 2001

This experiment was executed to clarify the optimum condition of reductive bleaching for 100% color papers. The reductive bleaching of the color paper was desirable to be done under such conditions as high temperature over $60^{\circ}C$ and high consistency within possibly short time. The FAS bleaching like the sodium hydrosulfite required oxygen-free condition. Especially, as the mixture between pulps and chemicals was favored in case of the high consistency, it was actively recommended. Therefore, it is desirable to control the dosage with the type of the dyes, the nature, the dye content, the paper compositions, and the targeting initial and final brightness.

• Journal of Ginseng Research
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• 제14권2호
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• pp.135-141
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• 1990

In order to elucidate the mechanism of the leaf-burning disease of ginseng (Panax ginseng C.A. Meyer), the relationships between thylakoid membrane peroxidation and chlorophyll bleaching were investigated in comparison with the ones of soybean (Glycine max L). When I measured the rate of lipid peroxidation in the thylakoids of ginseng and soybean by irradiation of light(60 w.m-2), it was identified that, the remarkably lower rate of lipid peroxidation was found in the ginseng thylakoid than the case of soybean. When lipid peroxidation of ginseng thylakoid was induced in the dark, chlorophyll contents of thylakoid was not changed. The results suggest that lipid peroxidation does not affect the chlorophyll bleaching in ginseng thylakoid. Thylakoid membrane peroxidation as well as chlorophyll bleaching was closely related with photosynthetic electron transport. But, according to the quenching experiment active oxygen species induced lipid peroxidation may be different species in the case of chlorophyll bleaching.

• 펄프종이기술
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• 제33권5호
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• pp.25-29
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• 2001

Dimethyldioxirane (DMD), which is a source of active oxygen, is effective agent that can be used in chemical pulp bleaching. In this study, delignification of kraft bagasse pulp has been carried out by using DMD. The effect of the applied charge of DMD (as active oxygen) and pH of the delignification medium were studied. The optimum conditions of the applied DMD charge and pH of the delignification reaction were achieved at pH range from 8~9, 2% of DMD (as active oxygen) and the rest of delignification reaction conditions were $25^{\circ}C$, 60 min, and 12% pulp consistency. The development of brightness per unit kappa number removal (ΔBrightness/ Δ Kappa number) has highest value at the optimum condition. The study showed that the reactivity of kraft bagasse pulp be enhanced to wards alkaline hydrogen peroxide bleaching by pulp treatment with DMD.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.20.1-20.14
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• 2020

Objectives: To minimize the tooth sensitivity caused by in-office bleaching, many dentists use non-steroidal anti-inflammatory drugs and topical desensitizing gels containing potassium nitrate and sodium fluoride. This study aimed to evaluate the influence of these substances on inflammation and the expression of substance P and calcitonin gene-related peptide in pulp nerve fibers. Materials and Methods: Seventy-two rats were divided into 6 groups as follows: GI, control; GII, only dental bleaching; GIII, only ibuprofen; GIV, ibuprofen administered 30 minutes before and after the bleaching treatment and every 12 hours until the analysis; GV, only topical application of a desensitizing agent; and GVI, topical application of a desensitizing agent before dental bleaching. Placebo gel was applied to the upper left jaw and the bleaching agent was applied to the upper right jaw in all groups. Subsequently, the groups were divided into 3 subgroups based on the time of analysis: 0, 24, and 48 hours after bleaching (n = 8). The rats were euthanized and the maxillae were processed and evaluated by histopathological and immunohistochemical analyses. The data were analyzed using the Kruskal-Wallis test, followed by the Dunn test (p < 0.05). Results: In the bleaching groups, the inflammatory process and expression of neuropeptides decreased over time. The animals in which a desensitizing agent was applied showed better results within 24 hours. Conclusions: The use of a desensitizing agent had positive effects on inflammation and pain-related neuropeptide expression, minimizing the painful effects of dental bleaching treatment.

• 자연과학논문집
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• 제10권1호
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• pp.93-102
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• 1998

오존을 이용한 마직물의 표백효과를 연구하기 위하여 오존 발생 장치에 의해서 생성된 오존을 물에 용존시킨 오존처리액으로 마직물을 처리하였다. 마직물의 오존처리를 위하여 오존 발생기와 오존 용존조를 사용하였고, 표백 효과를 측정하기 위하여 오존으로 처리된 마직물을 Hunter의 백도, 인장강도, SEM사진을 측정하였다. 발생 오존의 농도는 전압이 높을수록, 원료 산소가스의 유량이 적을수록 증가하였다. 처리포의 표백효과는 오존의 순수 농도가 증가함에 따라 증가하였다. 처리포의 백색도는 처리온도가 $0-15^{\circ}C$, 처리시간이 20분일 때가 최적의 상태를 나타내었다. 처리포의 인장강도는 처리시간이 길수록, 온도를 높여줌에 따라 저하하였다.

• Restorative Dentistry and Endodontics
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• 제23권2호
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• pp.656-669
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• 1998

Hydrogen peroxide at high concentration during walking bleaching may cause damage to the tooth structure and to the surrounding periodontal tissues and may develop external root resorption. Clinically, It is so important to find a method of prevention or minimization of these complications. The efficacy of various chamber-irrigating agents to eliminate residual hydrogen peroxide after walking bleaching was examined and compared with water rinse in this study. Extracted human 46 premolars without any cementoenamel junction defects were treated endodontically and based with IRM to 1 mm below CEJ and totally bleached 3 times for each tooth with 30% hydrogen peroxide and sodium perborate. Upon completion of the 3rd walking bleaching procedure, the cervical portion and pulp chamber of each group of teeth were irrigated with catalase, 70% ethylalcohol, acetone, and distilled water. And then, a radicular hydrogen peroxide penetration was measured with spectrophotometer immediately after each bleaching and following treatment with each chamber-irrigating agents, and the significance of their eliminating efficacy of residual hydrogen peroxide was analyzed by Kruskal-Wallis test. The results were obtained as follows. 1. Cervical root penetration of hydrogen peroxide was increased as the bleaching procedure was repeated(P<.01). 2. The most effective irrigant that removed residual hydrogen peroxide was the catalase, and the least effective one was water rinsing (P<.01).; there was no significant difference between the acetone and ethanol group. 3. The Irrigation with antioxidant enzyme or water-displacement solutions can eliminate residual oxygen radicals from the pulp chamber effectively after walking bleaching. So, these agents can reduce adverse effects such as cervical external resorption and periapical inflammation and prevent residual $O_2$ from impeding composite resin polymerization, thus increase the bonding strength of composite resin. This, in turn reduces microleakage and discoloration of the esthetic restoration, extending its service-life.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.958-962
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• 2012

In single-molecule fluorescence experiment, the oxygen scavenging system is indispensable for avoiding photo-bleaching of fluorescent dyes. Here we report that the gloxy-based oxygen scavenging system commonly used in single molecule fluorescence experiments can disturb the solution pH considerably. To track in situ pH change, we utilized the pH-sensitive conformational transition of i-motif and examined the transition with ensemble and single-molecule FRET measurements. Based on our results, we also suggested several practical remedies for the stability of the solution pH.

• 펄프종이기술
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• 제35권3호
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• pp.74-78
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• 2003

The structural property of phenolic and non-phenolic lignin has an effect on the reaction rate of lignin by oxygen and chlorine dioxide respectively. Moreover, the undesirable degradation of cellulose followed by lignin degradation is influenced by chemical charge and reaction time. In this paper, several lignin model compounds were used to illuminate the interaction of oxygen and chlorine dioxide by varying the position of O and D(OD, DO, ODO and DOD), and gas chromatography method was used to investigate the degradation of lignin by determining the content of methoxyl groups in lignin. It was shown that structural properties of lignin models were more influential on the degradation and demethylation of lignin than the above combination. Combination of oxygen and chlorine dioxide, however, was more effective in degradation of lignin than only one stage, and three stages than two stages.

• 펄프종이기술
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• 제32권1호
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• pp.86-93
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• 2000

High Colored kraft bleaching effluent is one of the main constrains in pulp and paper industry due to its dissloved lignin derivatives. The degradation of lignin in pulp and paper mill effluent is mainly caused by white-rot fungi. This paper showed that the treatment with KS-62 fungus significantly reduced the color and chemical oxygen demand in the effluent. The amounts of Mn ions in the wastewater would play roles in the induction and activity of MnP (Managanese peroxidase). Extracellular MnP was isolated from the fungus KS-62. The treatment with the MnP had the most effective decolorizatiion in the wastewater treatment using nutrients mediu.