• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.554-562
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• 2007

Ceramide rich intercellular lipid lamellae are thought to be particularly important in maintaining the structural integrity of epidermal barrier. Ceramide is synthesized de novo by serine palmitoyltransferase (SPT) phospholipid intermediates, serine and palmitic acid persist within the stratum corneum. The ceramide which is synthesized is degraded with fatty acid and sphingosine by degradative enzyme ceramidase. The depletion of ceramide in stratum corneum was reported in the atopic dermatitis. As an effort to search for the dietary source for improving the level of ceramide in epidermis, the dietary effects of various-typed silk protein were compared. Seventy male NC/Nga mice, an animal model of atopic dermatitis, were divided into seven groups: group CA as an atopic control with control diet, group S: 1% crude sericin diet, group F: 1% crude fibroin diet, group PS : peptide pattern of sericin(Mw 5000), group PF: peptide pattern of fibroin (Mw 1500), group AS: manufactured the same as amino acid profile of sericin and group AF: manufactured the same as amino acid profile of fibroin. Ten male BALB/c mice were served as group C (control group) control diet. All mice were fed on diet and water ad libitum for 10 weeks. Dry skin condition was established in group CA as ceramide content was decreased. Despite a marked decrease of mRNA and prorein expression of SPT, enzyme do novo synthesis, ceramide content of group S was dramatically increased by inhibiting the mRNA and protein expression of degradative enzyme ceramidase. However, dietary supplementation of crude silk fibroin protein (group F) and in other groups that were supplemented with either amino acid or peptide type of sericin or fibroin did not increase the level of ceramide. Together, our data demonstrate that dietary supplementation of crude sericin is more effective at improving ceramide level in epidemis of NC/Nga mice.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1018-1025
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• 2016

Probiotics are considered as the best effective alternatives to antibiotics. The aim of this study was to characterize the probiotic potential of lactobacilli for use in swine farming by using in vitro evaluation methods. A total of 106 lactic acid bacterial isolates, originating from porcine feces, were first screened for the capacity to survive stresses considered important for putative probiotic strains. Sixteen isolates showed notable acid and bile resistance, antibacterial activity, and adherence to intestinal porcine epithelial cells (IPEC-1). One isolate, LR1, identified as Lactobacillus reuteri, was selected for extensive study of its probiotic and functional properties in IPEC-1 cell models. L. reuteri LR1 exhibited good adhesion to IPEC-1 cells and could inhibit the adhesion of enterotoxigenic Escherichia coli (ETEC) to IPEC-1 cells. L. reuteri LR1 could also modulate transcript and protein expression of cytokines involved in inflammation in IPEC-1 cells; the Lactobacillus strain inhibited the ETEC-induced expression of proinflammatory transcripts (IL-6 and TNF-α) and protein (IL-6), and increased the level of anti-inflammatory cytokine (IL-10). Measurement of the permeation of FD-4 showed that L. reuteri LR1 could maintain barrier integrity in monolayer IPEC-1 cells exposed to ETEC. Immunolocalization experiments showed L. reuteri LR1 could also prevent ETEC-induced tight junction ZO-1 disruption. Together, these results indicate that L. reuteri LR1 exhibits desirable probiotic properties and could be a potential probiotic for use in swine production.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.1
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• pp.63-71
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• 2015

Moisturizers are the most prescribed products in dermatology. Treatment with moisturizers aims to maintain skin integrity and overall well-being by providing a healthy appearance. Moisturizers perform very important functions in baby care; however, there are few studies on the effects of moisturizers on the skin of infants. To investigate the effects of moisturizers on the skin of healthy full-term infants and toddlers, thirty-one healthy, full-term, 6- to 36-month-old infants and toddlers without any dermatologic conditions received moisturizer applied to the whole body except the eyes and diaper area after bathing twice daily for 4 weeks. Clinical assessments were conducted before treatment, immediately after the treatment period, and 1 and 4 weeks after treatment. At all visits, skin hydration, transepidermal water loss (TEWL), skin pH, and skin roughness were measured, the skin surface was photographed, and any adverse events were recorded. After using moisturizer, skin hydration significantly increased and TEWL and roughness significantly decreased. The skin pH was modified to mildly acidic and the skin surface was visually smoother than before treatment. There were no statistical significant differences of effects of moisturizers according to age and sex, and adverse events were not observed. The results of moisturizer application on the skin were increased skin hydration, recovery of barrier function, balancing skin pH within a mildly acidic range, and increasing the smoothness of the skin surface for 4 weeks.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.421-433
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• 2023

The final disposal of spent nuclear fuel(SNF) from nuclear power plants takes place in a deep geological repository. The metal canister encasing the SNF is made of cast iron and copper, and is engineered to effectively isolate radioactive isotopes for a long period of time. The SNF is further shielded by a multi-barrier disposal system comprising both engineering and natural barriers. The deep disposal environment gradually changes to an anaerobic reducing environment. In this environment, sulfide is one of the most probable substances to induce corrosion of copper canister. Stress-corrosion cracking(SCC) triggered by sulfide can carry substantial implications for the integrity of the copper canister, potentially posing a significant threat to the long-term safety of the deep disposal repository. Sulfate can exist in various forms within the deep disposal environment or be introduced from the geosphere. Sulfate has the potential to be transformed into sulfide by sulfate-reducing bacteria(SRB), and this converted sulfide can contribute to the corrosion of the copper canister. Bentonite, which is considered as a potential material for buffering and backfilling, contains oxidized sulfate minerals such as gypsum(CaSO4). If there is sufficient space for microorganisms to thrive in the deep disposal environment and if electron donors such as organic carbon are adequately supplied, sulfate can be converted to sulfide through microbial activity. However, the majority of the sulfides generated in the deep disposal system or introduced from the geosphere will be intercepted by the buffer, with only a small amount reaching the metal canister. Pyrite, one of the potential sulfide minerals present in the deep disposal environment, can generate sulfates during the dissolution process, thereby contributing to the corrosion of the copper canister. However, the quantity of oxidation byproducts from pyrite is anticipated to be minimal due to its extremely low solubility. Moreover, the migration of these oxidized byproducts to the metal canister will be restricted by the low hydraulic conductivity of saturated bentonite. We have comprehensively analyzed and summarized key research cases related to the presence of sulfates, reduction processes, and the formation and behavior characteristics of sulfides and pyrite in the deep disposal environment. Our objective was to gain an understanding of the impact of sulfates and sulfides on the long-term safety of high-level radioactive waste disposal repository.