• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1104-1110
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• 1999

We condicted two experiments to evaluate the interaction among fumaric acid (FA), protected acids (PA), or no additional acid (NO) and two different levels of acid buffering capacity (BC) in diets for 14-d-old weaned pigs. BC was varied substituting mono-calcium phosphate and calcium sulfate for dicalcium phosphate and calcium carbonate. In the high BC diet plus PA, FA was also added. In Exp. 1, 48 gilts were raised for 31 days on the six diets, evaluating growth performance and fecal digestibility. In Exp. 2, 42 gilts were raised. With each diet three subjects were sacrificed after 19 days and four after 38 days. In addition, six subjects were sacrificed at weaning. Growth and carcass performance, ileal digestibility, bacterial populations and pH in the gut were assessed. The piglet performance and stomach, ileal and cecal pH, and empty body composition were not affected by the diets. Empty body composition other than ash content was affected by piglet age (p<0.01). The BC did not influence digestibility. The dietary inclusion of PA improved fecal digestibility of protein (p<0.05) compared to the addition of FA and NO. Ileal digestibility slightly increased with both acid additions (p<0.10), the groups receiving PA showing the higher values. Piglets fed diets with low BC had lower Lactobacillus and E. coli counts in the ileum (p=0.07) and higher Lactobacillus in the colon (p=0.08). Acidified diets tended to reduce E. coli counts in the ileum (p=0.10) and increased Lactobacillus in the colon (p=0.09). The addition in the diet of PA increased Lactobacillus in the ileum compared to the sole addition of free fumaric acid (p=0.07). The addition of protected acids, combined with free fumaric acid in the case of high BC diets, increased protein digestibility and Lactobacillus counts and reduced E.coli counts. Only some changes in the concentration of bacterial population can be expected with a diet of low BC.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.233-240
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• 2014

An in vitro study on cariogenic potential of four over-the-counter nutritional supplements for children was performed. The experimental groups were four over-the-counter nutritional supplements. The positive control group was 10% sucrose solution (S), and the negative control group was artificial saliva (T). The pH of each group, the buffering capacities, acid production, the microhardness changes of the bovine teeth specimens were measured. The pH of all experimental groups were lower than critical pH 5.5 where enamel demineralization starts. The buffering capacity of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was highest, and the Smart Chewable Vitamin A (JW Pharm Co., Korea) had the lowest buffering capacity. The reduction rates of the pH of the experimental groups were significantly higher than that of the negative control group (p < 0.05). The microhardness of enamel of all experimental groups and the positive control group significantly decreased. In contrast, the microhardness of enamel of the negative control group significantly increased after experiment (p < 0.05). The reduction rate of the microhardness of enamel of the Hama Vitamin Pharm (Hamsoa Pharm Co., Korea) was significantly higher and Hikid Plus (Sanga Pharm Co., Korea) was significantly lower than the other experimental groups.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.74-81
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• 2021

Silicon (Si) is recognized as a promising anode material for high-energy-density lithium-ion batteries. However, under a condition of electrode comparable to commercial graphite anodes with low binder content and a high electrode density, the practical use of Si is limited due to the huge volume change associated with Si-Li alloying/de-alloying. Here, we report a novel core-shell composite, having a reversible capacity of ~ 500 mAh g-1, by forming a shell composed of a mixture of nano-Si, graphite nanosheets and a pitch carbon on a spherical natural graphite particle. The electrochemical measurements are performed using electrodes with 2 wt % styrene butadiene rubber (SBR) and 2 wt.% carboxymethyl cellulose (CMC) binder in an electrode density of ~ 1.6 g cm-3. The core-shell composites having the reversible capacity of 478 mAh g-1 shows the outstanding capacity retention of 99% after 100 cycles with the initial coulombic efficiency of 90%. The heterostructure of core-shell composites appears to be very effective in buffering the volume change of Si during cycling.

• International Journal of Stem Cells
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• v.16 no.3
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• pp.356-362
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• 2023

Glutathione (GSH) is a chief cellular antioxidant, affecting stem cell functions. The cellular GSH level is dynamically altered by the redox buffering system and transcription factors, including NRF2. Additionally, GSH is differentially regulated in each organelle. We previously reported a protocol for monitoring the real-time GSH levels in live stem cells using the reversible GSH sensor FreSHtracer. However, GSH-based stem cell analysis needs be comprehensive and organelle-specific. Hence, in this study, we demonstrate a detailed protocol to measure the GSH regeneration capacity (GRC) in living stem cells by measuring the intensities of the FreSHtracer and the mitochondrial GSH sensor MitoFreSHtracer using a high-content screening confocal microscope. This protocol typically analyses the GRC in approximately 4 h following the seeding of the cells onto plates. This protocol is simple and quantitative. With some minor modifications, it can be employed flexibly to measure the GRC for the whole-cell area or just the mitochondria in all adherent mammalian stem cells.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.67-74
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• 2005

The aim of this study was to analyze the relationship between salivary flow, salivary buffer capacity, level of mutans streptococci and dental caries experience in Korean dental college students. A total of 81 students of the school of dentistry, Chonbuk national university, mean age of 26.1 years, were subjected to oral examination to establish the DMFT and DMFS according to WHO guidelines. Saliva samples from the students were collected for quantitating stimulated and unstimulated salivary flow rate. Buffering capacity was estimated using a commercial colorimetric strip test, and number of mutans streptococci was determined from stimulated saliva using a strip mutans test. The means of DMFT and DMFS were 6.57 and 12.65, respectively. The stimulated salivary flow rate was correlated with DMFT(${\acute{o}}\;=\;-0.219$) and high levels of salivary mutans streptococci were significantly correlated with higher DMFT and DMFS scores(P<0.05). Level of mutans streptococci was significantly correlated with dental caries experience, in both DMFT and DMFS score, and buffering capacity was inversely correlated to DMFT score. However, unstimulated salivary flow rate was not correlated with caries experience.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.195-202
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• 2023

The caries activities of some commercially available children's beverages were measured to determine the risk of dental caries and provide basic data for preventing dental caries. For the experimental beverage, the beverages with the highest market share among carbonated beverages, fruit beverages, milk, and fermented milk products sold in the domestic market were selected. As a control, 0.25% glucose trypticase soy broth was prepared and used. The pH of the beverages, titrate acid and buffering capacity, and the acid production and vitality were measured over time after inoculating the beverages with Streptococcus mutans. The pH of children's beverages was the lowest in soda (2.61±0.02), and milk had the lowest in titratable acid (14.00±0.58). Fermented milk (80.33±3.64) had the highest buffering capacity, and carbonated beverage (9.40±1.06) had the lowest (P<0.05). Carbonated beverages (3 hr and 25 min) had the highest acid production, and milk (4 hr) had the lowest. In conclusion, thorough oral hygiene management is necessary after consuming children's beverages because they have a low pH promote high acid production of S. mutans.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.4
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• pp.237-247
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• 2002

Air pollution by acid pollutants is problematic in the whole world. Water acidification has already been deteriorating the forest ecosystem. This study was conducted to analyze the acidity and chemical composition of the open precipitation and throughfall at forests with various geographic locations in Korea. The results of this study are as follows; The open precipitation pH was lowest in Seochun. The throughfall pH showed some buffering capacity in only Quercus mongolica stands. In Pinus rigida(Shingal and Seochun) stands, there was little difference from the open precipitation. Chemical composition of the open precipitation for each sampling site showed that $Ca^{2+}$, N $H_{4}$$^{+}$ and S $O_{4}$$^{2-}$ concentrations had higher value than other ions, and except these ions, the small quantity of ions showed different properties to each site. Changes of ion concentrations in the throughfall showed a tendency to increase. ion concentrations of the throughfall increased with washout and nutrient leaching from the trees. In conclusion, the influence was extended to the pure zone, and the frequency of acid rain is increasing. But, if the deposition of pollutants exceeds the capacity of purification, it would damage forest ecosystem. Further investigations are necessary to identify tolerant tree species to acid pollutants.nts.

• Journal of Korean society of Dental Hygiene
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• v.15 no.2
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• pp.311-317
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• 2015

Objectives: The purpose of this study was to identify the effects of xylitol and sorbitol mouth rinse on the salivary caries activity levels. Methods: The study subjects were 38 female college students in Gyeongju, Korea. The subjects visited the institution once a week for 4 weeks and the saliva samples were measured for the amount of salivary caries activity levels. The saliva was collected 5 times and incubated in Mitis Salivarius Agar for 48 hours(VS-1203P3L, Vision, Korea) and measured. Results: The Streptococcus mutans CFU decreased by statistically significant amounts as compared to before the experiment within the xylitol group and the sorbitol group(p<0.01). After three weeks of mouth rinse application, Streptococcus mutans CFU of the xylitol group and the sorbitol group showed statistically significant differences(p<0.05). The salivary flow rates within the xylitol group and sorbitol group increased by statistically significant amounts(p<0.01) than before the test. The change in the salivary buffering capacity decreased by a statistically significant amount as compared to before experiment within the xylitol group(p<0.01). Conclusions: The salivary caries activity levels decreased after using xylitol and sorbitol mouth rinse in CFU and the flow rate. The buffering activity levels increased within the xylitol group. Further follow-up studies would be necessary to identify the various effects of xylitol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1486-1491
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• 2017

In this paper, we propose a private multimedia caching scheme based on wireless local area network (WLAN) to improve the quality of service for high capacity and high quality multimedia streaming services which are recently increasing and to reduce the traffic load of core networks. The proposed caching scheme stores multimedia in the storage device mounted on WLAN APs and provides streaming services on its own without Internet connection in accordance with the request from clients. We have implemented a test network based on real commercial networks and measured the performance of the proposed caching scheme in terms of frames per second (FPS) and buffering time. According to the performance measurement results, the proposed caching scheme can reduce the average buffering time by 73.3% compared to the conventional streaming scheme. In addition, the proposed caching scheme can also improve the average FPS by 71.3% compared to the conventional streaming scheme.

• Journal of dental hygiene science
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• v.24 no.1
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• pp.54-61
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• 2024

Background: The Korean name for Angelica gigas Nakai (AGN) is Cham-dang-gui, which grows naturally or is cultivated, and its dried roots are used in traditional herbal medicines. The AGN root exert various pharmacological effects. Despite the various pharmacological effects of the AGN root, there are no reports on its anti-oral microbial effects. The purpose of this study was to reveal the anti-oral microbial effect and the microbial and biochemical changes in oral microorganisms according to the concentration of the ethanol extract of AGN (EAGN) root, and to confirm the possibility of using EAGN as a plant-derived functional substance for controlling oral infectious microorganisms. Methods: Disk diffusion test, growth measurement, biofilm formation assay, and measurements of acid production and buffering capacity were performed to confirm the antibacterial effect of EAGN. Results: EAGN showed anti-oral bacterial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans at all concentrations, with S. mutans showing a more susceptible effect at concentrations above 5.0 mg/ml and A. actinomycetemcomitans at 3.75 mg/ml. EAGN treatment significantly reduced A. actinomycetemcomitans growth at all concentrations tested. Biofilm formation was significantly reduced at concentrations above 3.75 mg/ml for S. mutans and 2.5 mg/ml for A. actinomycetemcomitans. Acid production in S. mutans and A. actinomycetemcomitans was significantly increased by treatment with EAGN, and the buffering capacities of S. mutans and A. actinomycetemcomitans increased from an EAGN concentration of 3.75 mg/ml and above. Conclusion: EAGN showed anti-oral bacterial effects against both S. mutans and A. actinomycetemcomitans at concentrations above 3.75 mg/ml, which were thought to be related to the inhibition of their growth and biofilm formation. Therefore, EAGN can be used as a safe functional substance derived from medicinal plants owing to its antibacterial effects against S. mutans and A. actinomycetemcomitans.