• Restorative Dentistry and Endodontics
• /
• v.39 no.4
• /
• pp.296-302
• /
• 2014

Objectives: It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of $CO_2$ and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods: In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness) were assigned to 3 groups (n = 15). In control group (CNT) no laser treatment was used. In groups COL and EYL, $CO_2$ and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results: The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were $8.65{\pm}1.75$, $12.12{\pm}3.02$, and $5.97{\pm}1.14MPa$, respectively. Data showed that application of $CO_2$ and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001). The highest bond strength was recorded in the COL group (p < 0.0001). In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions: Pretreatment of zirconia ceramic via $CO_2$ and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the $CO_2$ laser treated samples.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.5
• /
• pp.3191-3196
• /
• 2013

Leaf extracts of Cassia alata L (akapulko), traditionally used for treatment of a variety of diseases, were evaluated for their potential antitumor properties in vitro. MTT assays were used to examine the cytotoxic effects of crude extracts on five human cancer cell lines, namely MCF-7, derived from a breast carcinoma, SK-BR-3, another breast carcinoma, T24 a bladder carcinoma, Col 2, a colorectal carcinoma, and A549, a nonsmall cell lung adenocarcinoma. Hexane extracts showed remarkable cytotoxicity against MCF-7, T24, and Col 2 in a dose-dependent manner. This observation was confirmed by morphological investigation using light microscopy. Further bioassay-directed fractionation of the cytotoxic extract led to the isolation of a TLC-pure isolate labeled as f6l. Isolate f6l was further evaluated using MTT assay and morphological and biochemical investigations, which likewise showed selectivity to MCF-7, T24, and Col 2 cells with $IC_{50}$ values of 16, 17, and 17 ${\mu}g/ml$, respectively. Isolate f6l, however, showed no cytotoxicity towards the non-cancer Chinese hamster ovarian cell line (CHO-AA8). Cytochemical investigation using DAPI staining and biochemical investigation using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-a method used to detect DNA fragmentation-together with caspase assay, demonstrated apoptotic cell death. Spectral characterization of isolate f6l revealed that it contained polyunsaturated fatty acid esters. Considering the cytotoxicity profile and its mode of action, f6l might represent a new promising compound with potential for development as an anticancer drug with low or no toxicity to non-cancer cells used in this study.

• The Pure and Applied Mathematics
• /
• v.8 no.1
• /
• pp.25-32
• /
• 2001

Let A be a nonnegative matrix of size $n \times n$. A is said to be nearly convertible if A(i│j) is convertible for all integers i, j$\in${1,2,…, n} where A(i│j) denote the submatrix obtained from A by deleting the i-th row and the j-th col-umn. We investigate some properties of nearly convertible matrices and existence of (maximal)nearly convertible matrices of size n is proved for any integers $n(\geq 3)$.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.3
• /
• pp.399-406
• /
• 2015

In this study, we developed a composite filler comprising cross-linked hyaluronic acid (HA) and human collagen (COL) derived from the human umbilical cord with the aim of improving its biocompatibility and longevity compared with commercially available fillers. After HA/COL composite fillers were made in two different ratios (10:1 and 5:1), the physical properties of the fillers were evaluated. The interior morphologies and in vivo weight change of these hydrogels were also characterized at 1-16 weeks after injection into mice. To evaluate their biocompatibility and durability in vivo, we injected the composite fillers into nude mice subcutaneously. The variations of injected gel weight were measured and compared with the commercial dermal fillers (Restylane and TheraFill). The composites showed improved or similar physical properties (complex viscosity of 19-22 × 10⁵ cP, and injection force of 10-12 N) over the commercial dermal fillers. Sixteen weeks following the injection, the ratio of remaining composite filler weight to initial weight (75.5 ± 16.9%; 10:1) was shown to be greater than that of the commercial fillers (43.2 ± 8.1%, Restylane; 12.3 ± 5.3%, TheraFill). In addition, immunohistochemical analysis with angiogenesis-related markers such as isolectin and vWF revealed newly formed blood vessels and cellular influx into the composite filler, which were not observed in the other fillers. These results clearly suggest that the HA/COL composite filler is a superior candidate for soft tissue reconstruction. The filler we developed may be a suitable candidate as an injectable dermal filler for tissue augmentation in humans.

• Korean Journal of Medicinal Crop Science
• /
• v.6 no.3
• /
• pp.165-169
• /
• 1998

To evaluate the intraspecific variations among the Kasiogalpi(Eleutherococcus senticosus Max.) collections. randomly amplified DNA polymorphisms were examined. Twenty primers from 90 primers applied were selected. The range of polymorphism was $7.1{\sim}90.9%$ in 113 randomly and specifically amplified DNA fragments. Collections were divided into two major groups at the similarity coefficient value of 0.65. A considerable degree of genetic diversity was also detected among plants within the same collections. Deokyu (1, 2, 3, 4, 6), Bukhaedo (7, 8) and Odae (9, 10) col1ections showed higher degree of genetic similarity with a value of $0.65{\sim}0.86$, while Deokyu 5 showed much lower genetic similarity than other col1ections.

• Journal of Applied Biological Chemistry
• /
• v.66
• /
• pp.424-435
• /
• 2023

As a result of this study, DPPH radical scavenging activity was 81.8% at a concentration of 100 ㎍/mL of Alpinia galanga L. rhizome 70% ethanol extract (AG.E), and ABTS⁺ radical scavenging activity was confirmed to be 99.8%, similar to L-Ascorbic acid (AA), at a low concentration of 50 ㎍/mL AG.E. To measure anti-aging activity, collagenase and elastase inhibitory activities were measured and AG.E showed higher inhibitory effects than epigallocatechin gallate (EGCG) starting at a low concentration of 50 ㎍/mL. In particular, AG.E showed inhibitory effects more than three times that of EGCG at a concentration of 500 ㎍/mL. In order to verify anti-aging effect of AG.E in CCD-986sk cell, good anti-aging effect was obtained in various experiments stimulated with UVB. In a gene expression analysis experiment using RT-PCR, the COL1A mRNA expression level was found to increase 2.90 times compared to no addition at a low concentration of 20 ㎍/mL AG.E, confirming the possibility of developing it as a good functional material related to anti-aging. As a basic study on temporal biological activity preservation ratio of material when applied to formulations, AG.E, and AA were added to a stable W/O type emulsion and stored in a thermostat at 25 ℃ for 60 days. As a result of measuring DPPH and ABTS⁺ radical scavenging activities on the 1st, 30th, and 60th days, it was confirmed that antioxidant effects are maintained at a high level over time in formulations.

• Macromolecular Research
• /
• v.8 no.4
• /
• pp.179-185
• /
• 2000

Generally vascular grafts with a relatively large inner diameter (> 5 mm) have been successfully employed for replacement in the human body. However, the use of small diameter grafts is limited, because these grafts rapidly occlude due to the thrombosis. The ideal blood-contacting surface of a prosthesis would be an endothelial cell (EC) lining, because the confluent monolayer of healthy ECs that culture natural blood vessels represents the ideal nonthrombogenic surface. For vascular graft application, the stable EC adhesion on surface under How conditions is very important. In this study, the adhesive strength of ECs attached on polymer surfaces coated with collagen type IV (Col IV), fibronectin (Fn), laminin (Ln), and treated with corona was investigated onto polyurethane (PU) films. The EC-attached PU surfaces were mounted on parallel-plate flow chambers in a How system prepared for cell adhesiveness test. Three different shear stresses (100, 150, and 200 dyne/㎠) were applied to the How chambers and each shear stress was maintained for 120 min to investigate the effect of shear stress and surface treatment condition on the EC adhesion strength. It was observed that the EC adhesion strength on the surface-modified PU films was in the order of Ln≡Fn > Col IV > corona 》 control. More than 70% of the adhered cells were remained on surface-modified PU surface after applying the shear stress,200 dyne/㎠ for 2 hrs, whereas the cells were completely detached on the control PU surface within 10 min after applying the same shear stress. It seems that the type of adsorbed proteins and hydrophilicitv onto the PU surfaces play very important roles for cell adhesion strength.

• Food Science and Biotechnology
• /
• v.18 no.2
• /
• pp.396-401
• /
• 2009

The nucleotide sequence contains 2 open reading frames encoding a 45-amino-acid protein homologous to a transcriptional repressor protein CopG, and a 203-amino-acid protein homologous to a replication protein RepB. Putative countertranscribed RNA, a double-strand origin, and a single-strand origin were also identified. A shuttle vector, pUCL2.1, for various lactic acid bacteria (LAB) was constructed on the basis of the pCL2.1 replicon, into which an erythromycin-resistance gene as a marker and Escherichia coli ColE1 replication origin were inserted. pUCL2.1 was introduced into E. coli, Lc. lactis, Lactobacillus (Lb.) plantarum, Lb. paraplantarum, and Leuconostoc mesenteroides. The recombinant LAB maintained traits of transformed plasmid in the absence of selection pressure over 40 generations. Therefore, pUCL2.1 could be used as an E. coli/LAB shuttle vector, which is an essential to engineer recombinant LAB strains that are useful for food fermentations.

• Journal of Sericultural and Entomological Science
• /
• v.39 no.1
• /
• pp.1-11
• /
• 1997

In relations to cold acclimation, experiment was carried out to understand the seasonal changes in reserve substances of the mulberry. The shoot barks and leaves of three mulberry varieties(Kaeryangppong, Shinilppong and Yongcheonppong) were sampled, after that their reserve substances were analyzed. The cold hardiness of mulberry was investigated by DTA(Differential Thermal Analysis) method. To increase cold hardiness, gibberellin(100 ppm), kinetin(100 ppm) and Jambi 8 were sprayed on the mulberry leaves. After spraying, falling of the leaves of Yongcheonppong occured earier than the other varities. After the first frost, all of treatments except gibberellin were entirely fallen. Growth regulator extended the leaves fallen. After spraying, water of the shoot barks was not showed difference in the content among the treatments, but amino acid, carbohydrate and soluble protein increased from September to October. Starch content of the shoot barks and leaves was maximum in October, but thereafter decreased during wintering stage. In Shinilppong, Jambi 8 spray increased cold hardiness by 1-2$^{\circ}C$ more than no spray. It was concluded that the cold hardiness of the mulberry in midwinter is closely related to the reserve substances with spraying Jambi 8 on the mulberry leaves.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.50 no.2
• /
• pp.171-178
• /
• 2024

In this study, we aimed to determine the various effects of Osmanthus fragrans (O. fragrans) flower extract on the skin in order to utilize it as a cosmetic material. For this purpose, Osmanthus fragrans flower extract (OFFE) of Jeju Island was prepared and used in the experiment. The experiments were evaluated by the quantitative real-time polymerase chain reaction (qRT-PCR) and lipid droplet staining assay. First, the OFFE decreased the gene expressions of three representative pro-inflammatory cytokines (IL-8, IL-6, and IL-1α) and an inflammation-related enzyme, PTGS2 induced by poly I:C in epidermal keratinocytes. In addition, the OFFE increased the gene expression levels of collagen (COL1A1) and elastin (ELN) in dermal fibroblasts. Further, the OFFE showed the inhibitory effect in sebum production by linoleic acid in sebocytes. Therefore, from this study, it is expected that OFFE can be used as a natural cosmetic material for anti-inflammatory, anti-aging, and sebum inhibitory efficacy.