• Fire Science and Engineering
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• v.31 no.6
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• pp.23-32
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• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.

• Archives of Pharmacal Research
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• v.29 no.5
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• pp.375-383
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• 2006

The anti platelet effects of a novel guanidine derivative, KR-32570 ([5-(2-methoxy-5-chlorophenyl) furan-2-ylcarbonyl]guanidine), were investigated with an emphasis on the mechanisms underlying its inhibition of collagen-induced platelet aggregation. KR-32570 significantly inhibited the aggregation of washed rabbit platelets induced by collagen $(10{\mu}g/mL)$, thrombin (0.05 U/mL), arachidonic acid $(100{\mu}M)$, a thromboxane (TX) $A_2$ mimetic agent U46619 (9,11-dideoxy-9,11-methanoepoxy-prostaglandin $F_2,\;1{\mu}M$) and a $Ca^{2+}$ ATPase inhibitor thapsigargin $(0.5{\mu}M)$ ($IC_{50}$ values: $13.8{\pm}1.8,\;26.3{\pm}1.2,\;8.5{\pm}0.9,\;4.3{\pm}1.7\;and\;49.8{\pm}1.4{\mu}M$, respectively). KR-32570 inhibited the collagen-induced liberation of $[^3H]$arachidonic acid from the platelets in a concentration dependent manner with complete inhibition being observed at $50{\mu}M$. The $TXA_2$ synthase assay showed that KR-32570 also inhibited the conversion of the substrate $PGH_2$ to $TXB_2$ at all concentrations. Furthermore, KR-32570 significantly inhibited the $[Ca^{2+}]_i$ mobilization induced by collagen at $50{\mu}M$, which is the concentration that completely inhibits platelet aggregation. KR-32570 also decreased the level of collagen $(10{\mu}g/mL)$induced secretion of serotonin from the dense-granule contents of platelets, and inhibited the NHE-1-mediated rabbit platelet swelling induced by intracellular acidification. These results suggest that the antiplatelet activity of KR-32570 against collagen-induced platelet aggregation is mediated mainly by inhibiting the release of arachidonic acid, $TXA_2$ synthase, the mobilization of cytosolic $Ca^{2+}$ and NHE-1.

• Food Science and Preservation
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• v.24 no.1
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• pp.145-152
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• 2017

In this study, near infrared (NIR) spectroscopy known as a non-destructive analysis technique was applied to investigate peptide cleavage and consequent release of amino acids in soybean lumps as affected by its moisture content and incubation time during fermentation at 25 for 3 weeks. The NIR spectra of the soybean lump semi-dried and soaked in saline water showed that absorption intensity around 1,400 nm originating from hydrogen bonds of water decreased and absorption band shifted to 1,430 nm as moisture content decreased during incubation at 25 for 3 weeks. In addition, absorption around 2,050 nm which was assigned to amino groups increased as incubation time increased. NIR spectra data from 1,000 to 2,250 nm showed higher accuracy in the discriminant analysis between outside and inside parts of fermented soybean lumps than visible spectra result. NIR spectroscopy for the amino acid and moisture contents in traditional fermented soybean lumps showed relatively good accuracy with the multiple correlation coefficient ($R^2$) of 0.91 and 0.81, respectively, and root mean square error of cross validation (RMSECv) of 0.23 and 0.83%, respectively, in partial least square regression (PLSR). These results indicate that NIR spectral observations could be applicable to control the fermentation process for preparation of soybean products.

• Journal of Life Science
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• v.20 no.5
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• pp.736-744
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• 2010

The root of Playtcodon grandiflorum, called Platycodi radix, has been a favorite edible plant in Asia and contains a large amount of saponins. Melanoma cells (B16F10) were used to investigate the inhibitory effect of aged black Platycodi radix extract (ABPRE) on oxidative stress and matrix metalloproteinases (MMPs). Platycodon radix has been known to have a variety of medicinal effects such as prevention of gastric ulcers, antiallergenic activities, histamine release inhibition, and antioxidant effects. However, the mechanism of its action remains unclear in humans. ABPRE was prepared using ethanol extraction of aged black Platycodi radix. In an antioxidant effect study of ABPRE, it was observed that ABPRE specifically exhibited the scavenging activity of DPPH radical, but did not inhibit the production of malondialdehyde from lipid peroxidation. DNA oxidation was also blocked in the presence of ABPRE. In addition, ABPRE decreased the expression and activation of MMP-2 stimulated by phenazine methosulfate. Furthermore, ABPRE revealed the inhibitory effect on melanin production induced by L-dopa via antioxidant effect and the reduction of tyrosinase expression. Especially, the expression of antioxidant enzymes such as SOD-1 and SOD-2 regulated by Nrf2 was increased in the presence of ABPRE. Therefore, it appears that ABPRE may be a possible chemopreventive agent for the prevention of metastasis related to oxidative stress.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1782-1789
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• 2012

We have developed a novel type of polymer nanogel loaded with anticancer drug based on bio-derived poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA). ${\gamma}$-PGA is a highly anionic polymer that is synthesized naturally by microbial species, most prominently in various bacilli, and has been shown to have excellent biocompatibility. Thiolated ${\gamma}$-PGA was synthesized by covalent coupling between the carboxyl groups of ${\gamma}$-PGA and the primary amine group of cysteamine. Doxorubicin (Dox)-loaded ${\gamma}$-PGA nanogels were fabricated using the following steps: (1) an ionic nanocomplex was formed between thiolated ${\gamma}$-PGA as the negative charge component, and Dox as the positive charge component; (2) addition of poly(ethylene glycol) (PEG) induced hydrogen-bond interactions between thiol groups of thiolated ${\gamma}$-PGA and hydroxyl groups of PEG, resulting in the nanocomplex; and (3) disulfide crosslinked ${\gamma}$-PGA nanogels were fabricated by ultrasonication. The average size and surface charge of Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels in aqueous solution were $136.3{\pm}37.6$ nm and $-32.5{\pm}5.3$ mV, respectively. The loading amount of Dox was approximately 38.7 ${\mu}g$ per mg of ${\gamma}$-PGA nanogel. The Dox-loaded disulfide cross-linked ${\gamma}$-PGA nanogels showed controlled drug release behavior in the presence of reducing agents, glutathione (GSH) (1-10 mM). Through fluorescence microscopy and FACS, the cellular uptake of ${\gamma}$-PGA nanogels into breast cancer cells (MCF-7) was analyzed. The cytotoxic effect was evaluated using the MTT assay and was determined to be dependent on both the concentration and treatment time of ${\gamma}$-PGA nanogels. The bio-derived ${\gamma}$-PGA nanogels are expected to be a well-designed delivery carrier for controlled drug delivery applications.

• Journal of Adhesion and Interface
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• v.4 no.1
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• pp.1-8
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• 2003

In this work, the effect of PMR-15 content on the variation of surface free energy of the DGEBA/PMR-15 blend system was investigated in terms of contact angles and mechanical interfacial tests. Based on FT-IR result of the blend system. C=O (1,772, $1,778cm^{-1}$) and C-N ($1,372cm^{-1}$) peaks appeared with imidization of PMR-15 and -OH ($3,500cm^{-1}$) peak showed broadly at 10 phr of PMR-15 by ring-opening of epoxy. Contact angle measurements were performed by using deionized water and diiodomethane as testing liquids. As a result, the surface free energy of the blends gave a maximum value at 10 phr of PMR-15, due to the significant increasing of specific component. The mechanical interfacial properties measured from the critical stress intensity factor ($K_{IC}$) and the critical strain energy release rate ($G_{IC}$) showed a similar behavior with the results of surface energetics. This behavior was probably attributed to The improving of the interfacial adhesion between intermolecules, resulting from increasing the hydrogen bondings of the blends.

• Food Science and Preservation
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• v.18 no.3
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• pp.358-365
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• 2011

The antioxidant and neuronal cell-protective effects of hot water extract from commercial buckwheat tea (CBTE) were evaluated. The 2,2'-azino-bis(3-ethyl-benzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, ferric reducing antioxidant power (FRAP), and malondialdehyde (MDA) inhibitory effect of the CBTE increased in a dose-dependent manner. The Intracellular reactive oxygen species (ROS) accumulation that resulted from hydrogen peroxide ($H_2O_2$) treatment more significantly decreased when CBTE was present in the media than when the PC12 cells were treated only with $H_2O_2$. In the neuronal cell viability assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT), the aqueous extracts showed a protective effect against $H_2O_2$-induced neurotoxicity, and the lactate dehydrogenase (LDH) release into the medium was also inhibited by CBTE. The total phenolics of CBTE was 9,608.10 mg/100 g, and the major phenolic compounds were rutin (13.42 mg/100 g) and quercitrin (0.90 mg/100 g). These data suggested that CBTE, including the aforementioned phenolics, may be useful in reducing the risk of neurodegenerative disease.

• Biomolecules & Therapeutics
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• v.32 no.3
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• pp.329-340
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• 2024

Mangiferin is a kind of natural xanthone glycosides and is known to have various pharmacological activities. However, since the beneficial efficacy of this compound has not been reported in retinal pigment epithelial (RPE) cells, this study aimed to evaluate whether mangiferin could protect human RPE ARPE-19 cells from oxidative injury mimicked by hydrogen peroxide (H₂O₂). The results showed that mangiferin attenuated H₂O₂-induced cell viability reduction and DNA damage, while inhibiting reactive oxygen species (ROS) production and preserving diminished glutathione (GSH). Mangiferin also antagonized H₂O₂-induced inhibition of the expression and activity of antioxidant enzymes such as manganese superoxide dismutase and GSH peroxidase, which was associated with inhibition of mitochondrial ROS production. In addition, mangiferin protected ARPE-19 cells from H₂O₂-induced apoptosis by increasing the Bcl-2/Bax ratio, decreasing caspase-3 activation, and blocking poly(ADP-ribose) polymerase cleavage. Moreover, mangiferin suppressed the release of cytochrome c into the cytosol, which was achieved by interfering with mitochondrial membrane disruption. Furthermore, mangiferin increased the expression and activity of heme oxygenase-1 (HO-1) and nuclear factor-erythroid-2 related factor 2 (Nrf2). However, the inhibition of ROS production, cytoprotective and anti-apoptotic effects of mangiferin were significantly attenuated by the HO-1 inhibitor, indicating that mangiferin promoted Nrf2-mediated HO-1 activity to prevent ARPE-19 cells from oxidative injury. The results of this study suggest that mangiferin, as an Nrf2 activator, has potent ROS scavenging activity and may have the potential to protect oxidative stress-mediated ocular diseases.

• Korean Journal of Food Science and Technology
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• v.50 no.4
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• pp.383-390
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• 2018

Most neurodegenerative diseases are known to be influenced by oxidative stress. We investigated the anti-oxidative activity of the concentrate of fermented wild ginseng root culture (HLJG0701) containing ginsenosides Rg5 and Rk1. HLJG0701 showed effective DPPH and ABTS radical scavenging ability ($IC_{50}$: 16- and 4-fold dilution, respectively) and was inhibited dose-dependently by the $FeSO_4$-induced lipid peroxidation group (8- and 4-fold dilution: 2.3 and 1.5 nM, respectively). In MTT and LDH assays, 8-, 16-, 32- and 64-fold diluted HLJG0701 significantly increased cell viability by 70, 53, 35, and 26%, respectively. LDH released by HLJG0701 was reduced 1.3-fold with 8-fold diluted HLJG0701 compared to the $H_2O_2$-treated control. In addition, the inhibitory effect of HLJG0701 on oxidative stress in PC12 cells was confirmed by DCF-DA analysis (16-, 4-fold diluted HLJG0701: 50 and 68% ROS inhibition, respectively), TBARS (16- and 4-fold diluted HLJG0701: 50.7 and 46.5% inhibition, respectively), GPx (16- and 4-fold diluted HLJG0701: 133.3 and 227.3% release, respectively), and SOD analysis (16- and 4-fold diluted HLJG0701: 118.2 and 218.2% release, respectively). These results suggested that HLJG0701 protects neuronal cells by its anti-oxidative effects and hence can be a potential preventive material against neurodegenerative diseases.

• Tuberculosis and Respiratory Diseases
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• v.43 no.1
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• pp.46-53
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• 1996

Background: Endotoxin or lipopolysaccharide(LPS) can prime phagocytic cells such as polymorphonuclear leukocytes, monocytes or animal peritoneal macrophages to generate increased amounts of secretory products such as oxygen free radicals and tumor necrosis factor, which play an important role in developing adult respiratory distress syndrome in gram negative sepsis. Human alveolar macrophages(HAM) are continuously exposed to various stimuli inhaled into the alveoli, and the response to LPS might be different in HAM. Therefore, we investigated the effect of LPS pre-exposure on HAM adhered to plastic surface and A549 cell(type II human alveolar epithelial cell line) monolayer. Methods: HAM were isolated from bronchoalveolar lavage fluid from normal lung of the patients with localized lung cancer and esophageal cancer. LPS was exposed to HAM for 2hrs before or after adherence to plastic surface of 24-well Linbro plate and A549 cell monolayer. And then HAM was stimulated with PMA(phorbol myristate acetate) or fMLP(N-formyl-methionylleucyl-phenylalanine). The amount of hydrogen peroxide($H_2O_2$) production in the supernatant was measured on the principle of peroxidase-dependent oxidation of phenol red by hydrogen peroxide. Results: LPS pre-exposure could not enhance $H_2O_2$ production in neither HAM adhered to plastic surface nor one to A549 cell monolayer. But LPS even in the absence of PMA or fMLP stimulation directly increased $H_2O_2$ release in HAM if added after the adherence to A549 cell monolayer. Conclusion: Endotoxin does not prime HAM, but may directly activate HAM adhered to alveolar epithelial cells. Further investagation will be necessary.