• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.477-486
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• 1998

Recently the development of rotary instrument makes it possible that in root canal treatment operator saves much more time, maintans original curved canal shape and easily prepares continuous tapered root canal. The purpose of this experiment was to examine the smoothness of the internal surface of prepared root canal and the effectiveness of debridement in prepared root canal by SEM for the comparison of hand and Ni-Ti rotary instrument. 25 extracted human teeth were access opened and # 10 K-type file was introduced into canal until it was appeared at the apical foramen. The working length was established by subtracting 0.5mm from this measurement. Group 1. The root canal preparation was done to # 30 with working length and then step-back until # 45 with K-Flexofile (Maillefer, Swiss). Group 2. Root canal preparation was done by Naviflex Ni-Ti file (Brasseler, USA) as the same technique with group 1. Group 3. Canal was prepared by Profile .04 (Maillefer, Swiss) taper until #30. Group 4. With use of Quantec (Tycom, USA) root canal was prepared from file number 1 to 8. In group 1 and 2, the root canal irrigant was NaOCl and the other groups, NaOCl and RC-prep (Premine Dental Products, USA) was used. The prepared teeth were notched with high-speed bur as bucco-lingual direction and fractured with chisel and mallet, then examined with SEM. Group 1 showed smooth internal surface. There were scratches mainly to the axial direction. Group 2 showed similar characteristics to those in group 1. Group 3 showed more smoother and linear cutting surface with bised scratches. Group 4 has the almost same characteristics group 3 and there was no difference in the file design. Ni-Ti rotary root canal instrument prepare the dentinal wall more smoother than hand instrument. The effectiveness of debridement was not fully affected by file design. The isthmus area and accessory canals of the root canal system were not prepared in any group. According to the result, hand and rotary type instrumentation techniques were effective in removal of major amount of tissue from root canal but it was not complete. In the direction of cutting movement there was difference between them.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.243-253
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• 2000

The purpose of this in vitro study was to evaluate dentin bonding by two different dentin bonding systems(DBS) using acetone based primer or adhesive [All Bond 2(AB2), One Step(OS)] when they were applied by wet or dry bonding technique. Morphology of resin-dentin interface and hybrid layer thickness(HLT) were investigated using Confocal Laser Scanning Microscope(CLSM) and compared to shear bond strength(SBS). 72 extracted sound human molars were randomly divided into 4 groups of 18 teeth each - Group 1.(AW); AB2 by wet bonding. Group 2(AD); AB2 by dry bonding. Group 3.(OW); OS by wet bonding, Group 4.(OD); OS by dry bonding. In 6 teeth of each group, notch-shaped class V cavities(depth 2mm) were prepared on buccal and lingual surface at the cementoenamel juction(12 cavities per group). To obtain color contrast in CLSM observation, bonding resins of each DBS were mixed with rhodamine B and primer of AB2 was mixed with sodium fluorescein. Prepared teeth of each group were treated with AB2, OS, respectively according to the manufacturer's instructions except for dentin surface moisture treatment after acid etching. In group 1 and 3, after acid etching, excess water was removed with wet tissue(Kimwipes), leaving consistently shiny, visibly hydrated dentin surface. In group 2 and 4, dentin surface was dried for 10 seconds at 1 inch distance. The treated teeth were then packed with composite resin(${\AE}$litefil) and light-cured. 12 microscopic samples($60{\sim}80{\mu}m$ thickness) of each group were obtained after longitudinal section and grinding(Exakt cutting and grinding system). Morphological investigation of resin-dentin interface and HLT measurement using CLSM were done. For measurement of SBS, remaining 12 teeth of each group were flattened occlusally to remove all enamel and grinded to 500 grit SiC(Pedemet Specimen Preparation Equipment). After applying DBS on the exposed dentin surface, composite resin was applied in the shape of cylinder, which has 5mm diameter, 1.5mm thickness, and light cured. SBS was measured using Instron with a crosshead speed of 0.5mm/min. It was concluded as follows, 1. HLT of AW(mean: $2.59{\mu}m$) was thicker than any other group, and followed by AD, OW, OD in descending order(mean; 2.37, 2.28, $1.92{\mu}m$). Only OD had statistically significant differences(p<0.05) to AW and AD. 2. There were intimate contact of resin and dentin at the interface in wet bonding groups, but gaps or irregular interfaces were observed in dry bonding groups. 3. The length, diameter, density of resin tags were various even in the same group without significant differences between groups and lots of adhesive lateral branches were observed. 4. There were no statistically significant difference of SBS between AB2 and OS, but SBS of wet bonding groups were significantly higher(p<0.05) than dry bonding groups. 5. There were no consistent relationships between HLT and SBS.

• Nutrition Research and Practice
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• v.15 no.6
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• pp.715-731
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• 2021

BACKGROUND/OBJECTIVES: Premenstrual syndrome (PMS) is a disorder characterized by repeated emotional, behavioral, and physical symptoms before menstruation, and the exact cause and mechanism are uncertain. Hyperprolactinemia interferes with the normal production of estrogen and progesterone, leading to PMS symptoms. Thus, we judged that the inhibition of prolactin hypersecretion could mitigate PMS symptoms. MATERIALS/METHODS: Hordeum vulgare L. extract (HVE), Chrysanthemum zawadskii var. latilobum extract (CZE), and Lomens-P0 the mixture of these extracts were tested in subsequent experiments. The effect of extracts on prolactin secretion at the in vitro level was measured in GH3 cells. Nitric oxide and pro-inflammatory mediator expression were measured in RAW 264.7 cells to confirm the anti-inflammatory effect. Also, the hyperprolactinemic Institute for Cancer Research (ICR) mice model was used to measure extract effects on prolactin and hormone secretion and uterine inflammation. RESULTS: Anti-inflammatory effects of and prolactin secretion suppress by HVE and CZE were confirmed through in vitro experiments (P < 0.05). Treatment with Lomens-P0 inhibited prolactin secretion (P < 0.05) and restored normal sex hormone secretion in the hyperprolactinemia mice model. In addition, extracts significantly inhibited the expression of pro-inflammatory biomarkers, including interleukin-1𝛽, and -6, tumor necrosis factor-𝛼, inducible nitric oxide synthase, and cyclooxygenase-2 (P < 0.01). We used high-performance liquid chromatography analyses to identify tricin and chlorogenic acid as the respective components of HVE and CZE that inhibit prolactin secretion. The Lomens-P0, which includes tricin and chlorogenic acid, is expected to be effective in improving PMS symptoms in the human body. CONCLUSIONS: The Lomens-P0 suppressed the prolactin secretion in hyperprolactinemia mice, normalized the sex hormone imbalance, and significantly suppressed the expression of inflammatory markers in uterine tissue. This study suggests that Lomens-P0 may have the potential to prevent or remedy materials to PMS symptoms.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.1
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• pp.75-84
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• 2021

In this study, we investigated inhibitory effect of Tripeptide against particulate matter (PM)-induced damage in human keratinocytes. PM-induced cell death was inhibited by Tripeptide and the activity of aryl hydrocarbon receptor (AhR) also inhibited by Tripeptide resulting in reduced expression of its downstream targets, cytochrome P450 family 1 subfamily A member 1 (CYP1A1) and cyclooxygenase-2 (COX-2), which are responsible for toxic metabolites production and inflammation. Furthermore, PM-induced expressions of pro-inflammatory cytokines, matrix metalloproteinase-1 (MMP-1) and apoptosis-related factors were decreased by anti-oxidant activity of Tripeptide. From these results, it has been shown that the Tripeptide has protective effect against PM-induced skin damage not only through the inhibiting of keratinocyte death but also through the inhibiting the secretion of several damage-inducing factors to adjacent skin tissue. And the results suggested that Tripeptide with anti-pollution effect could be applied as a new functional cosmetic material.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.395-400
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• 2020

Pigs have been used widely in biomedical research owing to their physiologic and anatomic similarities to humans. Analysis of the hematologic and biochemical values in pigs is an important basis for biomedical research and veterinary clinical diagnosis, but research on transgenic pigs has been sparse. This study was conducted to obtain basic data on transgenic pigs and to describe and compare the reference values for hematologic and biochemical parameters in human tissue plasminogen activator (htPA) transgenic pigs vs normal pigs. Blood samples were obtained from 7 normal LY (Landrace-Yorkshire crossbred) pigs and 8 transgenic pigs and 16 hematologic and 15 serum biochemical parameters were tested. Among the hematologic parameters tested, significant differences were observed in the red blood cells (RBC), mean red blood cell hemoglobin (MCH), and lymphocytes (LYM), between the non-transgenic and transgenic pigs. Among the biochemical parameters tested, the blood urea nitrogen (BUN), total protein (TP), cholesterol (CHOL), alanine aminotransferase (ALT), creatinine (CREA), gamma glutamyl transpeptidase (GGT), globin (GOB), and amylase (AMYL) showed significant differences between the two groups. Thus, the values determined in this study can be used as basic reference values for transgenic pigs and will contribute to their use in biomedical research.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.179-184
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• 2021

Stratum corneum known as a skin barrier, which maintains water in skin, is the outer layer of the skin. Natural moisturizing factors (NMF) are one of the constituents in stratum corneum and amino acids are the highest components among NMF. In this study, we designed stearic acid-based solid lipid nanoparticles (SLNs) for improved skin penetration of serine (Ser). Ser-capsulated SLN was manufactured by double-melting emulsification method. The mean particle size and zeta potential of SLNs were 256.30 ~ 416.93 nm and -17.60 ~ -35.27 mV, respectively. The higher the degree of hydrophobicity or hydrophilicity of emulsifiers, the smaller the particle size and the higher the stability and capsulation rate. In addition, skin penetration was conducted using SkinEthic^TM RHE which is one of the reconstructed human epidermis models. The results of Ser penetration demonstrated that all SLNs enhanced than serine solution. The amount of enhanced Ser penetration from SLNs were approximately 4.1 ~ 6.2 times higher than that from Ser solution. Therefore, Ser-loaded SLN might be a promising drug delivery system for moisturizing formulation in cosmeceutical.

• Journal of the Korean Institute of Gas
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• v.26 no.3
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• pp.27-37
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• 2022

With the recent increase in the spread of ESS (Electric Storage System), the damage to human life and property is also rapidly increasing due to continuous fires caused by ESS. In the manufacture of urethane sandwich panels used in ESS, it is necessary to improve the flame retardant performance. In this study, in order to realize the flame retardant properties of flexible polyurethane foam, the effect of the tissue density of the product due to the change of the isocyanate functional group parameter that changes the physical properties of the product on the fire performance was studied. The product was manufactured by changing the density of the urethane structure, and combustion performance tests, gas toxicity tests, and smoke density tests were performed. As a result, it was confirmed that the total amount of heat released had excellent performance when the isocyanate functional group was high, and had no correlation with the maximum heat release rate. When the value of the isocyanate functional group was 2.7 or more, the collapse of the shape could be prevented. In the gas hazard test, the performance was increased when the isocyanate functional group was relatively high, so a flame retardant for the Char system, which had a dense structure and easy to form a carbonized film, was added. confirmed to be. Therefore, as a result of this study, it is thought that it will be possible to lay the foundation for the development of a flame retardant to replace the cheap urethane sandwich panel used in the past.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.3
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• pp.287-293
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• 2022

Gray hair is a representative sign of aging. Intrinsic aging, stress, and the external environment cause hair graying. Stress is known to be a major factor in the early onset of hair graying. We previously found that Pueraia lobata root extract (PLRE) can prevent hair graying by promoting melanin formation. However, it remains unknown whether PLRE can prevent hair graying induced by conditions of stress. In this study, we confirmed the effect of PLRE on stress-induced hair graying. A reporter cell line was newly constructed to confirm the expression of microphthalamia-associated transcription factor (MITF), the main transcription factor for melanin production. MITF expression and melanin pigmentation were reduced in human hair follicle tissue treated with the stress hormone cortisol or H₂O₂ to induce oxidative stress. PLRE treatment restored MITF expression and increased the amount of melanin pigment in the hair follicle. The expression of Tyrosinase related proteins-2 (TRP-2), a melanin synthesis enzyme in the hair follicle, also increased. In conclusion, PLRE can effectively prevent the inhibition of melanin synthesis by stress hormones and oxidative stress.

• Journal of Life Science
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• v.31 no.12
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• pp.1142-1148
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• 2021

As the average human lifespan has been extended, there has been a lot of interest in the quality of life of women after menopause. It is known that the average age of menopause among Korean women is 49.7 years, and the post-menopausal life of a woman takes up more than one third of her life. L-ascorbic acid (AsA) is known to be involved in the synthesis and maturation of collagen, a bone constituent protein. The aim of this review is to discuss the potential of AsA in bone health in postmenopausal women. AsA plays an important role in collagen biosynthesis, and collagen is a protein constituting bone and is a necessary material for calcification of the bone matrix. Collagen crosslinking is necessary for the stabilization and elasticity of collagen fibers during growth and matruation of animals, but an excessive increase is likely to lead to further aging because the movement of intercellular nutrients or waste is suppressed. AsA acts as a reducing agent to stabilize the immature collagen crosslinking and suppress pyridinoline production, a mature crosslinking. Therefore, AsA participates in collagen biosynthesis and helps bone tissue health, while regulating the excessive maturation of collagen crosslinking, it is expected to play an important role in bone-related problems that may occur in postmenopausal women.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.935-942
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• 2022

In doing interventional treatment under the guidance of ultrasonography, the medical team detects the legion site with ultrasonic equipment at first, and insert angio needle. In this situation, if the position of legion and the depth of inserted needle on the ultrasonographic screen are different from real position and depth, the needle is likely to damage a major blood vessel or tissue. Accordingly, we had wondered how much such differences between screen image and reality, and so decided to examine them. Using five ultrasonographic equipments manufactured from different companies in different years, this study tried to compare the lengths of the needle on the screen images and real lengths of it, and find out the factors affecting skewness of them. This study used hog meat chunk to mimic human flesh, and sausages as the target of needle. It compared penetrating depths of the needle as the images on the five equipments using single sample t test in the SPSS 22 statistical program. It was found that all the errors were statistically significant(<.05). So, this study decided that it was wrong to evaluate performances of the equipments by the makers and ages of them. It is necessary to do periodic quality controls of equipments and improve the skillfulness of sonographers to reduce error rates between real treatment areas and the images of them.