• Analytical Science and Technology
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• v.13 no.3
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• pp.351-356
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• 2000

The decolorization of wastewater and the collecting conditions of final sludge from hanji production were investigated. Black wastewater (50 mL) from the process cooking with NaOH could be effectively decolorized by 2.0 g of $Ca(OCl)_2$ So, if excess bleach $Ca(OCl)_2$ used in bleaching process were recycled, the decolorization of wastewater by adding less $Ca(OCl)_2$ would be successfully realized. However, the decolorization by electrolyzed oxidation was ineffective. The final sludge could be effectively collected by polymer coagulator, but the addition of $Al_2(SO_4)_3$ was required, and the pure fibrous sludge could not be collected. Therefore, surfactants such as triethanolamine and Triton X-100 were used instead of polymer coagulator. The collecting yield was obtained about 85% as good as those by polymer coagulator. When mixed surfactants were used in collecting the final sludge, $Al_2(SO_4)_3$ was not required. In addition, as the pure fibrous sludge could be collected, the effective recycling of sludges would be done.

• Food Science and Preservation
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• v.16 no.2
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• pp.292-298
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• 2009

This study investigated the microbial safeties and germination rates of five domestic sprout species(alfalfa, broccoli, clover, red cabbage, and red radish) grown from disinfected seeds. The 48 h germination rates of all seeds were over 90%, regardless of treatment. Seed total plate count(TPC) and coliform levels were reduced significantly(p<0.05) by treatment with 20,000 ppm calcium hypochlorite solution at $25^{\circ}C$ for 15 min, following FDA recommendations. However, after germination, all sprouts regardless of treatment exhibited bacterial counts of $10^7-10^8CFU/g$. Listeria monocytogenes was detected at $10^3-10^4CFU/g$ on germinated non-disinfected clover seeds at days 1, 2, and 5. In conclusion, although sprout germination from disinfected seeds potentially permits the growth of sprouts with lower pathogen counts, there were no significant differences in TPC or coliform levels between sprouts grown from disinfected seeds and control sprouts. Further work is needed to improve the microbial safety of cultivated sprouts and to find optimal conditions for seed germination.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.4
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• pp.335-343
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• 2014

Regenerative endodontic treatment has the potential to heal a necrotic pulp, which can affect root development in immature teeth. However, several drawbacks and unfavorable outcomes are associated with regenerative endodontic treatment, of which the most significant is coronal discoloration due to the presence of minocycline in triple antibiotic paste and mineral trioxide aggregate (MTA). To prevent tooth discoloration following pulp treatment, the modified triple antibiotics (ciprofloxacin, metronidazole, clindamycin) were used as canal disinfectants and Retro MTA, a $ZrO_2$-containing calcium aluminate cement, was used to seal the canal. Following access cavity acquisition, the canal was copiously irrigated with 2.5% sodium hypochlorite. A modified triple antibiotic paste was then applied to the canal. Once the tooth was asymptomatic (after between 3 and 8 weeks), Retro MTA was carefully placed over the blood clot or a collagen plug. Follow-up radiographs revealed normal periodontal ligament space and root development. In two cases, successful regenerative endodontic treatment of the infected immature tooth, without discoloration, was achieved with disinfection using modified triple antibiotics and Retro MTA sealing.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.11.1-11.10
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• 2018

Objectives: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. Materials and Methods: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. Results: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). Conclusions: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

• Restorative Dentistry and Endodontics
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• v.45 no.2
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• pp.4.1-4.6
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• 2020

Although numerous studies have been conducted on apexification using mineral trioxide aggregate (MTA), direct observation of extracted human teeth after the procedure has been rarely reported. This case report describes a mandibular premolar treated 2.5 years ago and extracted recently for orthodontic treatment. The tubercle of the right mandibular premolar of a 12-year-old boy with dens evaginatus was fractured and the pulp was exposed. The tooth was diagnosed with pulp necrosis and asymptomatic periapical abscess. During the first visit, copious irrigation was performed with 2.5% sodium hypochlorite. Calcium hydroxide paste was placed as an intracanal medicament. The sinus tract had disappeared at the second visit after 3 weeks. MTA was applied on to the bleeding point as a 4-mm-thick layer, followed by a 3-mm-thick gutta-percha filling and resin core build-up. After 2.5 years, the tooth and three other premolars were extracted for orthodontic treatment. The right and left mandibular premolars were scanned with micro-computed tomography to determine the root shape and canal anatomy. Irregular root growth was observed and the root outline of the right mandibular premolar differed from that of the contralateral tooth. Apexification with MTA leads to the formation of roots with irregular morphology, without any pulpal space.

• Journal of Environmental Health Sciences
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• v.43 no.2
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• pp.143-156
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• 2017

The purpose of this study was to investigate water quality through a field survey at six floor fountain sites. The floor fountain facilities were designed and operated in such a way that tap water was stored in a water tank and recycled repeatedly. The water tank was cleaned once or twice per week in the summer. The number of facility users was low during the day due to sweltering heat, but up to 40 people, mainly children, were using them around 8 pm. Since the operation time was as short as 30 minutes, it is considered necessary to extend it for at least one hour for the number of users. As a result of the water quality test of the reservoir tank prior to operation after cleaning, it was measured to be within drinking water quality standards at the six facilities. As a result of the water quality test after use, ammonia nitrogen was measured to be 1.45 mg/L at Site IV. This exceeded the drinking water quality standard of 0.5 mg/L. In the case of turbidity, two cases exceed at 7.38 and 4.52 NTU when applying 4 NTU as the water quality standard for waterscape facilities. Twenty-eight cases exceed the standard of drinking water quality. The result of microbiological tests, at five sites excepting Site I, where disinfectant was injected, was that the maximum total colony count was 180,000 CFU/mL, total coliforms was 2,100,000 CFU/100 mL, fecal coliforms was 4,600 CFU/100 mL, Escherichia coli was 170 MPN/100 mL and Enterococcus was 100 CFU/100 mL. This exceeded the water quality standards of drinking water. Children are very likely to inhale because the water spews from below and falls from above, so it is necessary to apply water quality standards for ammonia nitrogen, turbidity and microbes. Current floor fountain facilities are highly susceptible to disease caused by microbial contamination because of water cycling and reuse, so it is necessary to change the water every day, clean the water tank, and perform chlorination. Therefore, it is necessary to inject calcium hypochlorite according to the free chlorine water quality standard of swimming pools with a different water tank capacity. In addition, facilities should be improved to prevent the reuse of water by installing the water tank at a separate location.