• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.430-438
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• 2002

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins-Prodigy(Kerr, USA), Vitalescence(Ultradent, USA), Z 250(3M, USA), Filtek flow(3M, USA)- in an alkaline solution. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%), (b) Si loss(ppm), (c) degradation depth($\mu}m$). The results were as follows: 1. There was no significant difference between Prodigy and Vitalescence, also Z 250 and Filtek flow. But, there was significant difference between former group and latter group. 2. The sequence of the degree of degradation layer depth was in descending order by Z 250, Filtek flow, Prodigy, Vitalescence. There was significant difference among the materials. 3. The sequence of the Si loss was in descending order by Filtek flow, Z 250, Prodigy, Vitalescence. There was significant difference among the materials. 4. The correlation coefficient between mass loss and degradation layer depth(r=0.714, p<0.05), mass loss and Si loss(r=0.770, p<0.05), and degradation layer depth and Si loss(r=0.930, p<0.05) were relatively high. 5. When observed with SEM, destruction of bonding was observed between resin matrix and filler. 6. When observed with CLSM, degradation layer depth of composite resin surface was observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.4
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• pp.382-391
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• 2019

This study was aimed to assess the new trial for minimal cavity preparation in composite restoration combined with resin infiltration, focusing at application sequence. 32 human primary molars with early carious lesions around small cavity were selected and randomly divided into two groups, according to the sequence of cavity preparation (P), composite filling (F) and resin infiltration (I) as IPF and PFI group. Each group was assessed about amount of tooth reduction, features of resin infiltration, and marginal leakage around restoration. Amount of tooth reduction evaluated using micro-CT was decreased compared with the original lesion size in both groups. Features of resin infiltration were verified under confocal laser scanning microscopy. In both groups, infiltrant resin was found on all around the composite and maintained in spite of extent of decalcification even after artificial caries induction. Marginal micro leakage assessed with silver nitrate immersion and micro-CT was found more frequently in PFI group. The technique combining resin infiltration and composite restoration might ensure better adhesion prognosis as applied by the sequence of resin infiltration, cavity preparation, and composite filling. This new trial was thought meaningful in minimizing the cavity size and contributing to minimal invasive dentistry.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.4
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• pp.339-347
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• 2012

In previous studies, methods for enhancing cellular response on the Hydroxyapatite coated implant surface were described. In this study, the changes of surface characteristics such as surface roughness, contact angle, surface energy and surface morphology were observed when Hydroxyapatite coated Ti discs were immersed in NaCl solution for various time. Hydroxyapatite coated Ti discs were immersed in 0.9% NaCl solution for 7, 14 and 21 days at $37^{\circ}C$. The control group comprises dry identical discs not immersed in a solution. (n=3) All discs were dried in air completely and the surface roughness was measured using confocal laser scanning microscopy(CLSM). Static contact angle was recorded by video contact angle analyzer after dropping distilled water on the surface. The surface energy was calculated from contact angles of the three liquids. Surface was observed using a field emission-scanning electron microscope(FE-SEM). As a result, the surface roughness of immersed Hydroxyapatite coated Ti discs increased significantly and the contact angle decreased comparing with control group discs. The surface energy of immersed discs increased except for discs immersed for 14 days.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.301-309
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• 1997

The objective of this study was to determine the microtubule assembly and chromatin configuration during the first cell cycle in bovine oocytes following injection of spermatozoon, sperm head and tail. The microtubule and chromatin configuration was imaged with fluorescent labeled monoclonal ${\alpha}$-tubulin antibody and propidium iodide under laser scanning confocal microscope. Microtubule and chromatin dynamics in bovine oocytes following intracytoplasmic sperm injection (ICSI) were not different from those observed during in vitro fertilization (IVF). Following ICSI, the microtubular aster was observed around sperm midpiece. During pronuclear formation, the sperm aster was enlarged and seen around male and female pronuclei. At mitotic metaphase, the microtubular spindle assemble astral poles and chromosomes were aligned on the spindle equator. At mitosis, asters were concentrated to each spindle pole and they filled the cytoplasm. After injection of the isolated sperm head, the microtubular aster was not seen around sperm head in any cases (0/18). Instead, microtubules were organized from the cytoplasm, which filled the whole cytoplasm during pronuclear apposition. These microtubules seem to move male and female pronuclei. These results suggest that isolated sperm head can develop into normal pronucleus in mature bovine oocytes, and competent to participate syngamy with the ootid chromatin. The functional microtubules following isolated sperm head injection in bovine oocytes appeared to be organized solely from maternal stores.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.360-367
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• 2014

Candida albicans is an opportunistic and the most prevalent fungal pathogen that can cause superficial and systemic infections in immunocompromised patients. C. albicans can promote the transition from budding yeast to filamentous form, generating biofilms. Infections associated with C. albicans biofilms are frequently resistant to conventional antifungal therapy. Therefore, the development of more effective antifungal drugs related with biofilm formation is required urgently. The roots of Rheum undulatum have been used for medicinal purposes in Korea and China traditionally. The aim of present study was to evaluate the effect of R. undulatum extract upon preformed biofilms of 12 clinical C. albicans isolates and the antifungal activities. Its effect on preformed biofilms was evaluated using XTT reduction assay, and metabolic activity of all tested strains was reduced significantly ($49.4{\pm}6.0%$) at 0.098 mg/ml R. undulatum. The R. undulatum extract blocked the adhesion of C. albicans biofilms to polystyrene surfaces, and damaged the cell membrane integrity of C. albicans which was analyzed by CFDA, AM, and propidium iodide double staining. It caused cell lysis which was observed by Confocal laser scanning and phase contrast microscope after propidium iodide and neutral red staining, respectively. Membrane permeability was changed as evidenced by crystal violet uptake. The data suggest that R. undulatum inhibits biofilm formation by C. albicans, which can be associated with the damage of the cell membrane integrity, the changes in the membrane permeability and the cell lysis of C. albicans.

• The Journal of Engineering Geology
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• v.14 no.1
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• pp.47-60
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• 2004

The permeability coefficients were calculated by the homogenization analysis method with sufficient consideration of fracture geometry dependent on aperture change. According to the results of aperture measurements using a confocal laser scanning microscope, apertures on each measuring point display different magnitudes, indicating that fracture walls can not be assumed as parallel feature. After construction of fracture model based on the aperture values measured on each pressure level, the homogenization analysis was conducted to compute permeability coefficients. The calculated permeability coefficients distribute in the ranges of $10^{-1}~10^{-3}cm/sec$. Most of the specimens show decreasing permeability coefficients with the increase of the applied pressure. However, the decreasing rates of permeability coefficients do not show a constant trend on each pressure level. This phenomenon is well matched to the observation results of Chae et al. (2003). It proves that aperture change strongly influences on permeability characteristics. Three sections of each specimen have all different values of permeability coefficient. It suggests that the variation of permeability coefficient depends sensitively on aperture magnitudes and characteristics of fracture geometry. It is very important to consider accurate fracture geometries for analysis of permeability characteristics in rock fractures bearing different aperture distribution. Therefore, it needs to consider sufficiently the fracture geometries for calculating the permeability coefficients of fractures.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.5
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• pp.547-556
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• 2016

Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing $K^+$ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward $K^+$ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing $K^+$ channels (TASK-2). NIOK in the presence of $K^+$ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3096-3102
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• 2011

Vanilloid receptor, TRPV1 (transient receptor potential vanilloid 1) is a non-selective cation channel that responds to a variety of pain-eliciting material including capsaicin, pH, heat. Although, membrane trafficking of TRPV1 was not much known so far, TRPV1 was reported to interact with FIP3 (family of Rab11 interacting protein 3). FIP3 was identified as one of Rab11 interacting proteins that is recently reported important in membrane trafficking of several channel proteins directly or indirectly. Therefore, in this study, we examined the role of Rab11 in the membrane trafficking of TRPV1 using cell biological and biochemical techniques. Rab11 was found really colocalized with TRPV1 based on the result of confocal microscopy. However, GST-pulldown assay, one of biochemical technique, found that Rab11 did not interact with TRPV1. Although Rab11 does not interact with TRPV1 directly, we hypothesized that Rab11 is indeed involved in the membrane trafficking of TRPV1. In order to examine further the role of Rab11 in the membrane trafficking of TRPV1, the expression of TRPV1 on the membrane was examined when the expression of Rab11 was decreased down to about 50% by siRNA technique and found decreased significantly. From this result, we can conclude that Rab11 is involved in the membrane trafficking of TRPV1 in a way of including FIP3.

• Korean Journal of Medicinal Crop Science
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• v.18 no.3
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• pp.143-150
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• 2010

This study showed the increase of antitumor activities of water soluble E. sinica extract by nano-encapsulation process with lecithin. Five groups of lecithin only group (LO), lecithin nano-encapsulated E. sinica group (LE), E. sinica only group (EO), one negative control group (NCO) and positive control group (PCO) were set for several anticancer experiment and fed into Sarcoma-180 injected mice. The cytotoxicity of LE on the human normal kidney cell (HEK293) showed 14.8% lower than 19.2% of EO and 18.4% of LO. Growth of human liver carcinoma cell and human stomach carcinoma cell as representative of digestive system in vitro was inhibited up to about 85.1% and 87.3%, in adding 1.0 mg/$m{\ell}$ of LE, which values 15% higher than that from conventional EO. The survival rates of each mice group were 40%, 63%, 48%, 33% and 100%, respectively after 40 days of injecting Sarcoma-180. The increment of their body weights of the extract feeding groups was suppressed down to 10~15%, compared to the negative control. The nano-particles also reduced the hypertrophy of the internal organs such as spleen and liver down to 15~20%, compared to those as the other groups. Among them, LE effectively reduced the size of tumor form to 20%. From these results, in vitro and in vivo antitumor activities of E. sinica could be enhanced by using nano-encapsulation process with lecithin because of better permeation into the cancer cells by confocal observations.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.220-225
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• 2020

Hair is made of proteins containing various amino acids. Ultraviolet (UV) radiation is believed to be responsible for the most damaging effects of sunlight, and also plays an important role in hair aging. The purpose of this study was to investigate the changes in morphological and chemical structures after ultraviolet B (UVB) irradiation of human hair. The UVB-irradiated hair showed characteristic morphological and structural changes, compared to those of the normal hair. The result from a scanning electron microscope (SEM) equipped with an energy dispersive X-ray diffractometer (EDX) showed that the scale of UV-irradiated hair appeared to be rough and the amount of oxygen element was higher than that of the normal hair. Fluorescence and three dimensional (3D) topographical images were obtained by a confocal laser scanning microscope (CLSM). In 3D images, the green emission intensity of normal hair was much higher than that of fluorescing UVB-irradiated hair. The intensity of green emission reflects the intrinsic fluorescence of hair protein. Also, a fluorescent imaging method using fluorescamine reagent was used to identify the free amino groups resulting from a peptide bond breakage in UVB-irradiated hair. Strong blue fluorescence of UVB-irradiated hair, which indicates a very high level of amino groups, was observed by CLSM. Therefore, the fluorescamine as an extrinsic fluorescence could provide a useful tool to identify the peptide bond breakage in UVB-irradiated hair. Infrared image mapping was also employed to assess the cross-sections of normal and UVB-irradiated specimens to examine the oxidation of disulfide bonds. The degree of peak areas with strong absorbance for the disulfide mono-oxide was spread from the outside to the inside of hair. The spectroscopic techniques used alone, or in combination, launch new possibilities in the field of hair cosmetics.