• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.14-19
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• 2010

Angiogenesis is an important event involved in cell growth and wound healing process. However, the imbalance of growth factors causes diseases, such as ocular, inflammatory diseases. One of treatment of these diseases is to suppress the formation of blood vessels. Function and mechanism of gold nanoparticles (AuNPs) in the formation of blood vessels is not yet proved. Pigment epithelium derived factor (PEDF) is currently being offered anti-angiogenic materials. In this study, we postulated that AuNPs might have the ability to inhibit angiogenesis, the pivotal step in tumor growth, invasion and metastasis. We have demonstrated that AuNPs could inhibit vascular endothelial growth factor (VEGF) induced cell proliferation, angiogenesis in bovine retinal endothelial cells.

• Journal of Animal Science and Technology
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• v.55 no.4
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• pp.237-247
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• 2013

This study was to examine single or combined in vitro effects of environmental endocrine disruptors on boar sperm characteristics, oxidative stress damage in sperm and development of porcine IVF embryos. Addition of various concentration of NP (10, 20, $30{\mu}M$), DBP (10, 50, $100{\mu}M$) and BPA (1, 5 or $10{\mu}g/ml$) on boar sperm characteristics such as percentages of sperm motility, viability, membrane integrity and mitochondrial activity were dose-dependently decreased within 3, 6 or 9 hr incubation period (p<0.05). The overall detrimental effects increased with incubation time increasement. NP, DBP and BPA showed the detrimental effects on sperm membrane and mitochondria of energy production organelles affecting cell viability with the dependancy of dose and incubation time. In combination effects, NP ($10{\mu}M$) + DBP ($10{\mu}M$) significantly decreased boar general sperm characteristics for 3 or 6 hr incubation period compared with control (p<0.05). When both of NP and DBP concentrations (NP; $30{\mu}M$, DBP; $100{\mu}M$) increase, the detrimental effects on sperm characteristics were larger than those of low concentration combination (p<0.05). The inhibitory effects of NP ($30{\mu}M$) + BPA ($10{\mu}g/ml$) on sperm characteristics were larger than those of NP ($10{\mu}M$) + BPA ($1{\mu}g/ml$) (p<0.05). DBP ($100{\mu}M$) + BPA ($10{\mu}g/ml$) decreased sperm characteristics compared with the low concentration combination (DBP $10{\mu}M$ + BPA $1{\mu}g/ml$, p<0.05). This result indicates the detrimental effects of both chemicals on sperm characteristics were dose dependent. Addition of NP ($30{\mu}M$) + DBP ($100{\mu}M$), NP ($30{\mu}M$) + BPA ($10{\mu}g/ml$), DBP ($10{\mu}M$) + BPA ($1{\mu}g/ml$) or DBP ($100{\mu}M$) + BPA ($10{\mu}g/ml$) significantly increased lipid peroxidation for 3 or 6 hr incubation period (p<0.05) compared with no addition control. NP (${\geq}20{\mu}M$) decreased the percentages of IVF embryo development from morulae and blastocyst stages (p<0.05) and its detrimental effects were dose-dependant. BPA 0, 1, 5 or $10{\mu}g/ml$ decreased significantly and dose-dependently the percentage of morulae plus and blastocysts (p<0.05). Combinations of DBP ($100{\mu}M$) plus NP ($30{\mu}M$) and DBP ($100{\mu}M$) plus BPA ($10{\mu}g/ml$) did not affect on morulae and blastocyst development, but NP ($30{\mu}M$) plus BPA ($10{\mu}g/ml$) has significant detrimental effect on embryo development at these stages (p<0.05). These overall results indicate that the partial detrimental effects on boar sperm characteristics and embryo development by NP, DBP, BPA or the combination of these chemicals might be due to the increasement of lipid peroxidation and free radical formation in the cell and there were no specific interaction effects on boar sperm and embryo degeneration among the combined treatments.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3191-3195
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• 2012

New silver nanoparticle (AgNP)-loaded amino acid based hydrogels were synthesized successfully from poly (vinyl alcohol) (PVA) and poly(acryl amide-co-acryloyl phenyl alanine) (PAA) by redox polymerization. The formation of AgNP in hydrogels was confirmed by using a UV-Vis spectrophotometer and XRD. The structure and morphology of silver nanocomposite hydrogels were studied by using a scanning electron microscopy (SEM), which demonstrated scattered nanoparticles, ca. 10-20 nm. Thermogravimetric analysis revealed large differences of weight loss (i.e., 48%) between the prestine hydrogel and silver nanocomposite. The antibacterial studies of AgNP-loaded PAA (Ag-PAA) hydrogels was evaluated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. These Ag-PAA hydrogels showed significant activities against all the test bacteria. Newly developed hydrogels could be used for medical applications, such as artificial burn dressings.

• Advances in nano research
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• v.10 no.2
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• pp.139-150
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• 2021

In this study, phytochemicals present in Propolis Extract (PE) were employed as reducing and stabilizing reagents to synthesize silver nanoparticles. Three propolis-reduced silver nanoparticles (P-AgNPs1-3) were synthesized using increasing amounts of PE. P-AgNPs were treated with different cancer cells-lung (A549), cervix (HeLa) and colon (WiDr) - for 24, 48 and 72 h to evaluate their anti-proliferative activities. A non-cancerous cell type (L929) was also used to test whether suppressive effects of P-AgNPs on cancer cell proliferation were due to a general cytotoxic effect. The characterization results showed that the bioactive contents in propolis successfully induced particle formation. As the amount of PE increased, the particle size decreased; however, the size distribution range expanded. The antioxidant capacity of the particles increased with increased propolis amounts. P-AgNP1 exhibited almost equal inhibitory effects across all cancer cell types; however, P-AgNP2 was more effective on HeLa cells. P-AgNPs3 showed greater inhibitory effects in almost all cancer cells compared to other NPs and pure propolis. Consequently, the biological effects of P-AgNPs were highly dependent on PE amount, NP concentration, and cell type. These results suggest that AgNPs synthesized utilizing propolis phytochemicals might serve as anti-cancer agents, providing greater efficacy against cancer cells.

• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.71-77
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• 2016

There has been unknown polynomial time algorithm for cellular formation problem (CFP) that is one of the NP-hard problem. Therefore metaheuristic method has been applied this problem to obtain approximated solution. This paper shows the existence of polynomial-time heuristic algorithm in CFP. The proposed algorithm performs coarse-grained and fine-grained cell formation process. In coarse-grained cell formation process, the cell can be formed in accordance with machine frequently used that is the number of other products use same machine with special product. As a result, the machine can be assigned to most used cell. In fine-grained process, the product and machine are moved into other cell that has a improved grouping efficiency. For 35 experimental data, this heuristic algorithm performs better grouping efficiency for 12 data than best known of meta-heuristic methods.

• Clean Technology
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• v.10 no.4
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• pp.221-228
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• 2004

Ethoxylated Nonyl Phenol Series (NP-series), nonionic surfactants, were applied for forming microemulsions in supercritical $CO_2$. Measurement results of the solubility in supercritical $CO_2$ are in the following; NP-series were high soluble in carbon dioxide in spite of the fact that those were not $CO_2$-philic surfactants traditionally well known. Water in $CO_2$ microemulsions were also formed stably. A complexation of hydrophilic lengths for $CO_2$-philic parts of NP-Series surfactants was optimized by NP-4 surfactant(N=4) for forming the microemulsions through the experiments. Formation of microemulsions was confirmed by measuring the UV-Visible spectrum through a spectroscopic method and existence of water in the microemulsions was confirmed as well. In order to apply it for a metal surface treatment or electroplating, an experiment for forming acid(organic, inorganic) solution in $CO_2$ microemulsions was carried out. Ionic surfactant in the reaction to an acid solution became unstable to form microemulsions, however, nonionic surfactant was formed stably in the reaction. Results of the study will be utilized for expanding the application scope of supercritical $CO_2$ which is an environmental-friendly solvent.

• Development and Reproduction
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• v.11 no.3
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• pp.179-185
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• 2007

The estrogens and estrogenic endocrine disrupting chemicals(EDCs) function through a steroid nuclear receptor-mediated process and subsequently regulate the transcription of mRNA for a number of target proteins. The estrogen receptor-related receptors(ERRs), which are structurally similar to estrogen receptors, are members of orphan nuclear receptor in the nuclear receptor superfamily and their functions are known to be involved in the formation of extra-embryonic ectoderm. To investigate effects of EDCs on early embryogenesis and ERR gene expression in marine invertebrates, we examined morphological changes and the mRNA expression of $ERR{\beta}$ like 1 in sea urchin Strongylocentrotus nudus exposed to estradiol-$17{\beta}(E_2)$ or nonylphenol(NP). The $E_2$ and NP-exposed embryos showed a delayed development compared to control embryos. Furthermore, they showed abnormal embryonic developments at late stages, i.e., blastular, gastrula and plutei stages. The mRNA level of $ERR{\beta}$ like 1 at the gastrula stage was significantly lower in $E_2$ and NP-exposed embryos than those of control group. These results suggest that NP and $E_2$ are potent chemicals causing abnormal embryonic development of S. nudus through at least in part down-regulated $ERR{\beta}$ like 1.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2621-2624
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• 2014

The rapid and spontaneous adsorption of proteins on nanoparticle (NP) surfaces in biological fluids such as blood is an important phenomenon as it possibly determines "what the cells see" and, thus, the fates of NPs in living organisms. In order to quantitatively understand protein coronas at the molecular level, we investigated human serum albumin (HSA) coronas that were produced on silica NPs of 20 nm and 50 nm diameters using conventional gel electrophoresis. Analysis of the concentration dependence of protein adsorption showed that HSA coronas preferentially formed a monolayer on silica NPs and revealed the presence of hard protein coronas. HSA adsorption was clearly dependent on NP size, and this might be due to the different surface curvatures of NPs of different sizes.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.522-530
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• 2022

In this study we aimed to develop novel ZnO-NP/chitosan/β-glycerophosphate (ZnO-NP/CS/β-GP) antibacterial hydrogels for biomedical applications. According to the mass fraction ratio of ZnO-NPs to chitosan, mixtures of 1, 3, and 5% ZnO-NPs/CS/β-GP were prepared. Using the test-tube inversion method, scanning electron microscopy and Fourier-transform infrared spectroscopy, the influence of ZnO-NPs on gelation time, chemical composition, and cross-sectional microstructures were evaluated. Adding ZnO-NPs significantly improved the hydrogel's antibacterial activity as determined by bacteriostatic zone and colony counting. The hydrogel's bacteriostatic mechanism was investigated using live/dead fluorescent staining and scanning electron microscopy. In addition, crystal violet staining and MTT assay demonstrated that ZnO-NPs/CS/β-GP exhibited good antibacterial activity in inhibiting the formation of biofilms and eradicating existing biofilms. CCK-8 and live/dead cell staining methods revealed that the cell viability of gingival fibroblasts (L929) cocultured with hydrogel in each group was above 90% after 24, 48, and 72 h. These results suggest that ZnO-NPs improve the temperature sensitivity and bacteriostatic performance of chitosan/β-glycerophosphate (CS/β-GP), which could be injected into the periodontal pocket in solution form and quickly transformed into hydrogel adhesion on the gingiva, allowing for a straightforward and convenient procedure. In conclusion, ZnO-NP/CS/β-GP thermosensitive hydrogels could be expected to be utilized as adjuvant drugs for clinical prevention and treatment of peri-implant inflammation.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.41-47
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• 2019

PURPOSE. Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS. Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (${\alpha}=.05$). RESULTS. The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P<.001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION. Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.