• Journal of Mushroom
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• v.20 no.2
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• pp.86-91
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• 2022

Pleurotus eryngii, a white rot fungus, produces two extracellular lignin-degrading enzymes, laccase and manganese peroxidase (MnP). Owing to these enzymes, P. eryngii efficiently degrades synthetic chemicals such as azo, phthalocyanine, and triphenyl methane dyes. In this study, we investigated the degradation processes of four aromatic dyes, congo red (CR), methylene blue (MB), crystal violet (CV), and malachite green (MG), by P. eryngii under solid and liquid culture conditions. CR and MG were the most quickly degraded under solid and liquid culture conditions, respectively. However, compared to CR, CV, and MG, MB was not degraded well under both culture conditions. The activities of ligninolytic enzymes (laccase and MnP) were also investigated. Laccase was identified to be the major enzyme for dye degradation. A positive relationship between decolorization and enzyme activity was observed for CR, MB, and CV degradation. In contrast, decolorization of MG ensued after high enzyme activity. These results indicate that the degradation process differs between MG and the other aromatic dyes. Therefore, P. eryngii could be a potential tool for the bioremediation of synthetic aromatic dye effluent.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.91-96
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• 2012

AC and ZnS modified $TiO_2$ composites (AC/ZnS/$TiO_2$) were prepared using a sol-gel method. The composite obtained was characterized by Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, scanning electron microscope (SEM) analysis, and according to the UV-vis absorption spectra (UV-vis). XRD patterns of the composites showed that the AC/ZnS/$TiO_2$ composites contain a typical single and clear anatase phase. The surface properties as observed by SEM present the characterization of the texture of the AC/ZnS/$TiO_2$ composites, showing a homogenous composition in the particles showing the micro-surface structures and morphology of the composites. The EDX spectra of the elemental identification showed the presence of C and Ti with Zn and S peaks for the AC/ZnS/$TiO_2$ composite. UV-vis patterns of the composites showed that these composites had greater photocatalytic activity under visible light irradiation. A rhodamine B (Rh.B) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of Rh.B was determined using UV/Vis spectrophotometry. An increase in the photocatalytic activity was observed. From the photocatalytic results, the excellent activity of the Y-fullerene/$TiO_2$ composites for the degradation of methylene blue under visible irradiation could be attributed to an increase in the photo-absorption effect caused by the ZnS and to the cooperative effect of the AC.

• Textile Coloration and Finishing
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• v.26 no.2
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• pp.88-98
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• 2014

This study is to assess the photocatalytic degradation of PET and Nylon 6 films containing nano-sized $TiO_2$ powders of anatase and rutile types. The PET and Nylon 6 films containing six kinds of the nanoparticles were prepared by melt casting method using a heating press machine. Reflectance in visible region and water contact angles of the irradiated PET and Nylon 6 composite films decreased with increasing UV/$O_3$ irradiation. Also the enhanced hydrophilicity has a close relationship with the increase in the Lewis base parameter, which indicates more oxidized polymer surfaces. The photocatalytic degradation of the nanocomposite films increased with increasing $TiO_2$ content and UV energy, which is more significant with the anatase types rather than the rutile types. The amide linkages in the Nylon 6 seemed to be more susceptible to the UV light compared to the ester groups in the PET, particularly in the presence of the $TiO_2$ photocatalysts. The photoscission and photodegradation of the polymers in the composites produced more degraded structure assisted by the photocatalytic activity of the $TiO_2$ nanoparticles. Also the composite films can bleach the methylene blue dyes more easily under the UV/$O_3$ irradiation, suggesting the photobleaching activity of the $TiO_2$ nanoparticles.

• The korean journal of orthodontics
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• v.36 no.6
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• pp.451-464
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• 2006

The purpose of this study was to search for an appropriate method of coating $TiO_2$ on orthodontic appliances. $TiO_2$ thin films were deposited on orthodontic wires and brackets using sol-gel, CVD (Chemical Vapor Deposition) and PE-CVD (Plasma Enhanced-CVD) methods. The roughness of $TiO_2$-coated surfaces was investigated via scanning electron microscope (SEM) and adhesive strength of $TiO_2$ thin films was measured by adhesive tape pull test. Methylene blue degradation test was carried out to evaluate the photocatalytic activity of $TiO_2$ and the corrosion resistance of $TiO_2$ thin films against fluoride solution was also analyzed by observing the surfaces of $TiO_2$-coated wires and brackets via SEM after immersion in sodium fluoride solution. Through the comparison of properties and photocatalytic activity of $TiO_2$ thin films according to the coating methods, the following results were obtained. Smoother surfaces of $TiO_2$ thin films were generated by CVD or PE-CVD methods than through the sol-gel method or the control. Adhesive strength of the $TiO_2$ thin films was highest in PE-CVD and gradually became lower in the order of CVD, then the sol-gel method. Photocatalytic activity of $TiO_2$ thin films on methylene blue was the highest in PE-CVD and gradually became lower in the order of CVD, then the sol-gel method. Corrosion resistance of $TiO_2$ thin films against fluoride solution was stronger in CVD and PE-CVD methods than in the sol-gel method. The results of this study suggest that the CVD or PE-CVD methods is more appropriate than the sol-gel method for $TiO_2$ coating on orthodontic wires and brackets.

• Applied Chemistry for Engineering
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• v.32 no.6
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• pp.632-639
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• 2021

In this research, fluorine doping was performed to enhance the photocatalytic activities of WO₃ which were measured using methylene blue dye. WO_3-xF_x photocatalyts were prepared by a vaper phase fluorination during a sintering for preparing WO₃ photocatalysts from a WCl₆ precursor. The bandgap energy of WO₃ photocatalysts decreased from 2.95 eV to 2.54 eV, and the oxygen vacancies site increased by about 55% after fluorine doping. In addition, the initial degradation efficiency of methylene blue showed that the fluorine doped sample showed a 6-fold increase in photocatalytic activities from 10% to 60% compared to that of the untreated sample. It is believed that fluorine is doped to reduce the band gap of photocatalysts, enabling the catalytic activity with low energy, and that oxygen vacancies-generated surface defects increase the visible light absorption region of WO₃ photocatalysts, thereby increasing photocatalytic activity. In this study, it was confirmed that fluorine-doped WO_3-xF_x photocatalysts with an excellent photocatalytic activity can be manufactured easily using a one-step vaper phase fluorination that does not require a post-treatment process.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.159-165
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• 2022

To enhance the photocatalytic activities of WO₃ photocatalysts, fluorine doping was performed to induce the oxygen vacancies. Both plasma and direct vaper fluorination were carried out for fluorine doping, and photocatalytic activities were examined by using methylene blue dye. Oxygen vacancies of the plasma and direct vaper fluorinated WO₃ photocatalysts were measured to be 14.65 and 18.59%, which increased to about 23 and 56% at pristine WO₃ photocatalysts. The degradation efficiency of methylene blue was also determined about 1.7 and 3.4 times higher than pristine WO₃ photocatalysts, respectively, depending on oxygen vacancies increased. In addition, it was confirmed that the bandgap process energy decreased from 2.95 eV to 2.64 and 2.45 eV after fluorine doping. From this result, it is considered that the direct vaper fluorination has an advantage for increasing the photocatalytic activities of WO₃ compared to that of the plasma fluorination.

• Journal of Mushroom
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• v.17 no.4
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• pp.247-254
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• 2019

Trametes hirsuta, a white rot fungus, exhibits the ability to degrade synthetic aromatic dyes such as congo red (CR), methylene blue (MB), crystal violet (CV), and remazol brilliant blue R (RBBR). The mycelia of T. hirsuta degraded RBBR and CR more efficiently than CV and MB in the PDB liquid medium (supplemented with 0.01% 4 aromatic dyes). In these mycelia the activities of three ligninolytic enzymes-laccase, manganese peroxidase (MnP), and lignin peroxidase (LiP)-were observed. Among these, laccase was identified to be the major enzyme responsible for the degradation of the four aromatic dyes. The degradation of bisphenol A was also investigated by culturing the mycelia of T. hirsuta in YMG medium supplemented with 100 ppm bisphenol A. The mycelia of T. hirsuta were found to degrade bisphenol A by 71.3, 95.3, and 100 % within incubation periods of 12, 24, and 36 hr, respectively. These mycelia also showed ligninolytic enzyme-like activities including those similar to laccase, MnP, and LiP. Therefore, these results indicate that T. hirsuta could emerge as a potential tool for the remediation of environmental contamination by aromatic dyes and bisphenol A.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.754-759
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• 2011

Zinc protoporphyrin (ZnPP) is produced endogenously during heme metabolism and treated in cells as a heme oxygenase inhibitor. In the present study, the effects of ZnPP on the color response of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a commonly-used method for analyzing cell viability, were investigated. ZnPP induced rapid decolorizaion of MTT formazan under light; the degradation rates were 10- and 20- folds faster in the presence of 5 and $10{\mu}M$ ZnPP, respectively. Methylene blue (MB), another type of photosensitizer, also accelerated degradation of formazan under light. Butylated hyroxytoluene did not inhibit ZnPP- or MB-induced formazan degradation. The color degradation of formazan dye was signficantly delayed in the presence of N-acetylcysteine or ${\beta}$-carotene. The present results suggest that certain photosensitizing compounds may affect the color and stability of MTT formazan, which should be carefully considered when conducting the MTT assay.

• The korean journal of orthodontics
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• v.46 no.3
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• pp.146-154
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• 2016

Objective: Different methods have been utilized to prevent enamel demineralization and other complications during orthodontic treatment. However, none of these methods can offer long-lasting and effective prevention of orthodontic complications or interventions after complications occur. Considering the photocatalytic effect of $TiO_2$ on organic compounds, we hoped to synthesize a novel bracket with a $TiO_2$ thin film to develop a photocatalytic antimicrobial effect. Methods: The sol-gel dip coating method was used to prepare $TiO_2$ thin films on ceramic bracket surfaces. Twenty groups of samples were composed according to the experimental parameters. Crystalline structure and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively; film thickness was examined with a surface ellipsometer. The photocatalytic properties under ultraviolet (UV) light irradiation were analyzed by evaluating the degradation ratio of methylene blue (MB) at a certain time. Antibacterial activities of selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. Results: Films with 5 coating layers annealed at $700^{\circ}C$ showed the greatest photocatalytic activity in terms of MB decomposition under UV light irradiation. $TiO_2$ thin films with 5 coating layers annealed at $700^{\circ}C$ exhibited the greatest antimicrobial activity under UV-A light irradiation. Conclusions: These results provide promising guidance in prevention of demineralization by increasing antimicrobial activities of film coated brackets.

• Journal of Periodontal and Implant Science
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• v.45 no.4
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• pp.145-151
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• 2015

Purpose: The aim of this study was to investigate the therapeutic effects of a herbal formula, PerioH-035, containing Angelica sinensis, steamed Rehmannia glutinosa, Angelica dahurica, Cimicifuga heracleifolia, and Zanthoxylum piperitum on the periodontal breakdown in a well-established ligature-induced periodontitis model in rats. Methods: Sprague-Dawley rats were randomly assigned to 1 of 4 groups: NL (non-ligatured), L (ligatured), P1 (ligatured and treated with 1 mg/mL PerioH-035), P100 (ligatured and treated with 100 mg/mL PerioH-035). Periodontitis was induced by placing a ligature around the mandibular first molars. PerioH-035 was topically applied to both sides of the first molar for 2 weeks. The right side of the mandibles was retrieved for micro-computed tomography (CT) and methylene blue staining to analyze alveolar bone loss. The left side of the mandibles was histologically analyzed by TRAP and H&E staining. The MMP-9 mRNA level in gingival tissue was investigated by RT-PCR. Results: Alveolar bone resorption was significantly reduced in the PerioH-035-treated groups. The number of dense multi-nucleated cells found to be TRAP-positive by staining in the ligatured rats was markedly decreased by PerioH-035 application. In addition, periodontal tissue destruction, especially cementum demineralization, was ameliorated in the P1 and P100 groups. Moreover, gingival tissue from the PerioH-035-treated group showed a decrease in the MMP-9 mRNA level, resulting in recovery of collagen degradation. Conclusions: These results suggest that PerioH-035 has therapeutic effects on periodontitis, and thus, PerioH-035 shows promise as a treatment for periodontitis.