• Applied Biological Chemistry
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• v.37 no.5
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• pp.326-333
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• 1994

Pleurotus florida with high cellulase activity as well as lignin degradability was selected out among strains for fermentation of the rice straw to improve the nutritive value. When the rice straw was fermented by P. florida, the contents of hemicellulose, cellulose and lignin were decreased to 22.5%, 11.4% and 28.1%, respectively, whereas the contents of rice straw fermented after pretreatment with $H_2O_2$ or alkaline hydrogen peroxide were decreased much in the lower concentration. The content of T-N (total-nitrogen) and crude fat was increased with the longer fermentation period. The amino acid content of rice straw fermented by P. florida in 30 days was increased to 28.9% and 35.1% as the rice straw was fermented after pretreatment without and with 4% $H_2O_2$, respectively. The crystalline intensity of rice straw was decreased by pretreatment with 4% $H_2O_2$ and fermentation by P. florida. However, the crystall intensity was increased by treatment with alkaline hydrogen peroxide and the more when the straw was washed after the treatment. When the rice straw was fermented by P. florida for 30 days, the in vitro organic matter digestibility was increased up to 6% of $H_2O_2$ pretreatment.

• Restorative Dentistry and Endodontics
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• v.48 no.2
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• pp.12.1-12.11
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• 2023

Objectives: The present study evaluated the pulp response of human mandibular incisors subjected to in-office dental bleaching using gels with medium or high concentrations of hydrogen peroxide (HP). Materials and Methods: The following groups were compared: 35% HP (HP35; n = 5) or 20% HP (HP20; n = 4). In the control group (CONT; n = 2), no dental bleaching was performed. The color change (CC) was registered at baseline and after 2 days using the Vita Classical shade guide. Tooth sensitivity (TS) was also recorded for 2 days post-bleaching. The teeth were extracted 2 days after the clinical procedure and subjected to histological analysis. The CC and overall scores for histological evaluation were evaluated by the Kruskal-Wallis and Mann-Whitney tests. The percentage of patients with TS was evaluated by the Fisher exact test (α = 0.05). Results: The CC and TS of the HP35 group were significantly higher than those of the CONT group (p < 0.05) and the HP20 group showed an intermediate response, without significant differences from either the HP35 or CONT group (p > 0.05). In both experimental groups, the coronal pulp tissue exhibited partial necrosis associated with tertiary dentin deposition. Overall, the subjacent pulp tissue exhibited a mild inflammatory response. Conclusions: In-office bleaching therapies using bleaching gels with 20% or 35% HP caused similar pulp damage to the mandibular incisors, characterized by partial necrosis, tertiary dentin deposition, and mild inflammation.

• Korean Journal of Pharmacognosy
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• v.45 no.1
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• pp.11-16
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• 2014

Protocatechuic acid is an active phenolic acid compound from Momordica charantia. In this study, we investigated the protective effect of protocatechuic acid against oxidative stress under cellular system using C6 glial cell. The oxidative stress was induced by hydrogen peroxide ($H_2O_2$) and amyloid beta 25-35 ($A{\beta}_{25-35}$), and they caused the decrease of cell viability and overproduction of reactive oxygen species (ROS). However, the treatment of protocatechuic acid significantly elevated the decreased cell viability and inhibited the overproduction of ROS by $H_2O_2$. In addition, protocatechuic acid significantly recovered the cellular damage induced by $A{\beta}_{25-35}$. In particular, protocatechuic acid at the concentration $10{\mu}g/mL$ decreased the elevated ROS level to normal level. These results indicate that protocatechuic acid may have neuroprotective effect through attenuating oxidative stress.

• Korean Journal of Health Education and Promotion
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• v.13 no.2
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• pp.167-183
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• 1996

Human teeth vary widely in color. Practitioner and patients are concerned with preventing and correcting discolored or dark teeth to achieve and maintain stain-free, white teeth. Tooth brushing cannot alter tooth color but it can remove adhering films and stains. The esthetics of natural dentition can be improved by bleaching and this process can be applied to intrinsically and extrinsically stained teeth. The need for a brighter, more attractive smile has made rapid growth in the market for tooth whiteners. There is no doubt these products work as whiteners, at least on mild to moderate stains, but the safety of these products are unclear. In this experiment, the effect of tooth whitener application on the color and microhardness of extracted human enamel was measured. RMS, RMT and NWT were used as tooth whiteners, and tooth paste(ETQ) and hydrogen peroxide solution(HPO) were used as controls. 35 caries-free extracted human molars were embedded and polished with the exposed enamel diameter of 4 mm. The tooth whiteners and control agents were applied according to the manufacturers' instructions or clinically simulated procedures for eight weeks, and measurements were repeated every two weeks. Value(L＊) difference was measured using Differential Colorimeter(Model TC-6FX, Denshoku Co., Japan), and microhardness was measured using microhardness tester(Mitsuzawa Seiki Co., Japan). The results were as follows; 1. After application of agents for eight weeks, the Vickers hardness increased significantly in the ETQ, RMS and RMT application group(p〈0.01), and that decreased significantly in NWT application group(p〈0.01), but in HPO application group there was no significant change. The change in microhardness was greatest in NWT application group(p〈0.01). 2. After application of tooth whiteners and controls for eight weeks, the value change of toothpaste application group was significantly lower than those of other agents groups(p〈0.01), and there was no significant difference in value(L＊) change among tooth whitener groups(p〉0.01). 3. The application of tooth paste and paste type tooth whitener made gradual value change, but hydrogen peroxide gel type tooth whitener and hydrogen peroxide solution made rapid value change during initial application period.

• Journal of Food Hygiene and Safety
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• v.32 no.6
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• pp.447-454
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• 2017

A new amperometric biosensor has been developed for the detection of hydrogen peroxide ($H_2O_2$). The sensor was fabricated through the one-step deposition of a biocomposite layer onto a glassy carbon electrode at neutral pH. The biocomposite, as a $H_2O_2$ sensing element, was prepared by the electrochemical deposition of a homogeneous mixture of graphene oxide, aniline, and horseradish peroxidase. The experimental results clearly demonstrated of that the sensor possessed high electrocatalytic activity and responded to $H_2O_2$ with a stable and rapid manners. Scanning electron microscopy, cyclic voltammetry, and amperometry were performed to optimize the characteristics of the sensor and to evaluate its sensing chemistry. The sensor exhibited a linear response to $H_2O_2$ in the range of 10 to $500{\mu}M$ concentrations, and its detection limit was calculated to be $1.3{\mu}M$. The proposed sensing-chemistry strategy and the sensor format were simple, cost-effective, and feasible for analysis of "food-grade $H_2O_2$" in food samples.

• The Plant Pathology Journal
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• v.35 no.4
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• pp.287-300
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• 2019

Spot blotch caused by Bipolaris sorokiniana has spread to more than 9 million ha of wheat in the warm, humid areas of the Eastern Gangetic Plains (EGP) of South Asia and is a disease of major concern in other similar wheat growing regions worldwide. Differential lignin content in resistant and susceptible genotypes and its association with free radicals such as hydrogen peroxide ($H_2O_2$), superoxide ($O_2{^-}$) and hydroxyl radical ($OH^-$) were studied after inoculation under field conditions for two consecutive years. $H_2O_2$ significantly influenced lignin content in flag leaves, whereas there was a negative correlation among lignin and $H_2O_2$ to the Area Under Disease Progress Curve (AUDPC). The production of $H_2O_2$ was higher in the resistant genotypes than susceptible ones. The $O_2{^-}$ and $OH^-$ positively correlated with AUDPC but negatively with lignin content. This study illustrates that $H_2O_2$ has a vital role in prompting lignification and thereby resistance to spot blotch in wheat. We used cluster analysis to separate the resistant and susceptible genotypes by phenotypic and biochemical traits. $H_2O_2$ associated lignin production significantly reduced the number of appressoria and penetration pegs. We visualized the effect of lignin in disease resistance using differential histochemical staining of tissue from resistant and susceptible genotypes, which shows the variable accumulation of hydrogen peroxide and lignin around penetration sites.

• Restorative Dentistry and Endodontics
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• v.45 no.1
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• pp.12.1-12.8
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• 2020

Objectives: The aim of this in vitro study was to evaluate the microhardness and surface roughness of composite resins before and after tooth bleaching procedures. Materials and Methods: Sixty specimens were prepared of each composite resin (Filtek Supreme XT and Opallis), and BisCover LV surface sealant was applied to half of the specimens. Thirty enamel samples were obtained from the buccal and lingual surfaces of human molars for use as the control group. The surface roughness and microhardness were measured before and after bleaching procedures with 35% hydrogen peroxide or 16% carbamide (n = 10). Data were analyzed using 1-way analysis of variance and the Fisher test (α = 0.05). Results: Neither hydrogen peroxide nor carbamide peroxide treatment significantly altered the hardness of the composite resins, regardless of surface sealant application; however, both treatments significantly decreased the hardness of the tooth samples (p < 0.05). The bleaching did not cause any change in surface roughness, with the exception of the unsealed Opallis composite resin and dental enamel, both of which displayed an increase in surface roughness after bleaching with carbamide peroxide (p < 0.05). Conclusions: The microhardness and surface roughness of enamel and Opallis composite resin were influenced by bleaching procedures.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.121-129
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• 1997

This study was performed to delineate the removal phenol in solutions using of ozone, ozone/$H_2O_2$ and ozone/GAC. The disinfection by-product of phenol by ozonation, hydroquinone, was analyzed and it's control process was investigated. The followings are the conclusions that were derived from this study. 1. The removal efficiency of phenol by ozonation was 58.37%, 48.34%, 42.15%, and 35.41% which the initial concentration of phenol was 5 mg/l, 10 mg/l, 15 mg/l, and 20 mg/l, respectively. 2. The removal efficiency of phenol by ozonation was 42.95% at pH 4.0 and 69.39% at pH 10, respectively. The removal efficiencies were gradually increased, as pH values were increased. 3. With the ozone/$H_2O_2$ combined system, the removal efficiency of phenol was 72.87%. It showed a more complete degradation of phenol with ozone/$H_2O_2$ compared with ozone alone. 4. When ozonation was followed by filtration on GAC, phenol was completely removed. 5. Oxidation, if carried to completion, truly destroys the organic compounds, converting them to carbon dioxide. Unless reaction completely processed, disinfection by-products would be produced. To remove them, ozone/GAC treatment was used. The results showed that disinfection by-product of phenol by ozonation, hydroquinone, was completely removed. These results suggested that ozone/GAC should also be an appropriate way to remove phenol and its by-product.

• Fashion & Textile Research Journal
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• v.5 no.5
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• pp.520-528
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• 2003

Chitosan was depolymerized by oxidizing agent, hydrogen peroxide ($H_2O_2$) and general properties of resulting low molecular weight chitosan(LMWC) were studied. Effect of amount of $H_2O_2$, ratio of $H_2O_2$/chitosan, and reaction temperature were investigated in preparing LMWC. In addition, the reduction of molecular weight of prepared LMWC were measured after a certain time passage. Pre-swelling treatment of starting chitosan affected uniform and mild reaction of depolymerization and increased the solubility of resulting LMWC. Prepared LMWC (Mw 100,000) showed a decrease in Mw by 25-35%. Prepared LMWC(Mw 60,000-70,000) showed a decrease in Mw by 10-15% after 7 months. Therefore, this depolymerizing process can be concluded desirable in terms of stability. In addition, yellowing of pre-swelling treated chitosan upon time passage was insignificant compared with that of untreated chitosan. Therefore, pre-swelling treatment of chitosan before depolymerization would be beneficial in terms of stability of physical state.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.67-67
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• 2003

Minocycline is known to protect neurons from microglia-mediated cell death in many experimental models of brain diseases including ischemic stroke, Huntingtons disease (HD), amyotrophic lateral sclerosis (ALS), traumatic brain injury, multiple sclerosis, and Parkinsons disease. When the activity of caspases was assessed using their fluorescent peptide substrates, activation of caspase-2, 3, 8, and 9 was evident within 2 8 hr following oxidative insult with 0.5 mM hydrogen peroxide in PC12 cells. Minocycline significantly attenuated activation of these caspases up to 18 hr, resulting a significant increase in the cell viability as assessed by MTT assay as well as trypan blue staining. However, cleavage of alpha-spectrin and a cdk5 activator p35, which are known to be substrates for calpain, remained unchanged in the presence of minocycline, suggesting that minocycline did not block caspase-3-independent cell death or necrosis. Moreover, co-treatment with minocycline and a calpain inhibitor calpeptin synergistically inhibited hydrogen peroxide-induced cell death. These data suggest that minocycline directly inhibited apoptosis, but not necrosis, after oxidative insult in PC12 cells.