• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.6
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• pp.1014-1019
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• 2011

Curcumin is a natural phytochemical present in turmeric, the ground powder of the rhizomes of Curcuma longa. Curcumin has been described as having antioxidant, anti-inflammatory, and anti-carcinogenic properties. However, it is still largely unknown whether curcumin inhibits the UVB-induced inflammatory reaction in HaCaT keratinocyte cell lines. In this study, to confirm the photoprotection properties of curcumin, HaCaT keratinocyte cells were irradiated by UVB, and then treated with curcumin. UVB irradiation induced the increased expressions of IL-$1{\beta}$, TNF-${\alpha}$, IL-6, IL-8, and COX-2 in HaCaT cells. These increased expressions of cytokines (IL-$1{\beta}$, TNF-${\alpha}$, IL-6, IL-8, and COX-2) were down-regulated by curcumin treatment in UVB-irradiated HaCaT cells. In addition skin of hairless mice were damaged by UVB irradiation, which were evidenced by atrophy of epidermis and decrease of collagen in dermis. However, these damages were protected partially by co-treatment of curcumin. Taken together, this data indicate that curcumin may be a promising photoprotection agent, when used in massage pack or sunscreen product, to reduce cell death in UV-damaged skin.

• Korean Journal of Microbiology
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• v.17 no.4
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• pp.165-178
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• 1979

Phages of Lactobaciilus casei (PLC) isolated from plant drainage were classified and characterized. The results are as follows : 1. On the basis of host range pattern, phages could be divided into 2 groups (PLC-B and PLC-C). PLC-B group phages could be further divided into 5 sub-groups $(B_1, \;B_2, \;B_3, \;B_4, \;and\;B_5)$. Although PLC-C group phages had the same host range, they could be also divided into 2 sub-groups $(C_1\;and\;C_2)$ by morphlogical type. 2. It was $B_3$ group phages that represented a major proportion (44.4%) of phages tested. However, $B_1$ group phages were shown to have the widest host range. 3. Electron micrographs revealed that the phages fell into three different morphological types. $(B_1, \;B_2, \;and\;B_3)$ group phages hd a hexagonal head (52nm in diameter) and a sheathless noncontractile (245 nm in length). $B_4\;and\;C_2$ group phages had a hexagonal head (56 nm) and a short flexible tail (169nm) having no sheath. $B_5\;and\;C_1$ group phages were shown to have a hexagonal head (81 nm) and a contractile tail (140 nm) having a sheath, a base plate and tail fibers. 4. The inactivation of the phages by antisera indicated that serological relationships correlated completely with morphological types. 5. $B_1, \;C_1\;and\;C_2$ group phages produced a large (1, 2 mm in diameter) plaque with a clear ring. The morphology of plaques of $B_3\;and\;B_5$ group phages was the same as those produced by the above, but the average plaque sizes for $B_3\;and\;B_5$ were 0.8 mm abd 0.5 mm, respectively. $B_2\;and\;B_4$ group phages produced a small (0.5 mm) turbid plaque with an irregular edge. 6. The latent period and the average burst size of $B_1\;and\;B_3$ group phages were 90 min and 100, respectively. These phages reuqired calcium ions for their miltiplication. 7. $B_3$ group phages could not be absrobed to R-variant $KC_1$. 8. The order of resistance of phages to heat was $B_2\;>\;B_1, B_4\;and\;B_5\;>\;B_3\;and\;C_2, \;B_5$ group phages were more stable than $B_3$ in various pH values. $C_2$ group phages were more sensitive to UV irradiation than $B_1\;and\;B_3$ group phages. 9. Strains YIT9018 and IAM 1043 were induced by mitomycin C treatment. Phage particles detected in the lysates had a hexagonal head (38 and 49 nm, respectively), but no tail. Any sensitive indicator strain could not be isolated in spite of repaeated trials.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.95-101
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• 2024

In this study, we investigated the migration level of items specified in the Korean Standards and Specifications for Utensils, Containers, and Packages (Ministry of Food and Drug Safety Notification) for 50 utensils and hygiene products made of biodegradable resins. Our results revealed that one Polylactide (PLA) baby tableware contained 20 mg/L in consumption of potassium permanganate, exceeding the standard of 10 mg/L or less. In all other samples, formaldehyde, lead (Pb), and arsenic (As) levels could be considered very safe and remained below the standard. Moreover, we tested the PLA baby tablewares (n = 21) for migration into a food simulant (4% v/v acetic acid) upon repeated elution at 100℃ for 30 min or UV irradiation for 2 h. We detected increased formaldehyde and As amounts at the repeated 100℃ treatment for 30 min compared to those upon repeated UV irradiation. However, the migration level was markedly low under both conditions. Furthermore, the Estimated Daily Intake (EDI) calculated on an infant-to-child basis from the formaldehyde and As migration at 100℃ for 30 min in the PLA sample was at the maximum value, i.e., 6.0×10^-4 mg/kg b.w./day and 1.3×10^-1 ㎍/kg b.w./day, corresponding to 0.40% and 10.42% of the Tolerable Daily Intake (TDI, 0.15 mg/kg b.w./day) and Provisional Tolerable Weekly Intake (PTWI, 9.0 ㎍/kg b.w./week), respectively. Therefore, in this study, we confirmed that biodegradable synthetic resins are safe to use for food.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.714-718
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• 2015

Both lead molybdate ($PbMoO_4$) and chromium substituted lead molybdate ($PbMo_{1-x}Cr_xO_4$) were successfully synthesized using a conventional hydrothermal method and characterized by XRD, DRS, Raman, SEM and PL. We also investigated the photocatalytic activity of these materials for the decomposition of rhodamine B under UV-visible irradiation. The XRD and Raman results revealed the successful synthesis of well-crystallized $PbMoO_4$ crystals with the diameter of 51-59 nm, regardless of the addition of chromium ion. The DRS spectra of $PbMo_{1-x}Cr_xO_4$ catalysts showed new intensive absorption bands in the visible region. The $PbMoO_4$ catalysts showed the lowest photocatalytic activity and the activity increased with an increase of chromium substitution amounts under visible irradiation. PL peaks appeared at about 540-580 nm for all catalysts and excitonic PL signals were proportional to the photocatalytic activity for the decomposition of rhodamine B.

• Journal of the Korean Chemical Society
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• v.60 no.1
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• pp.34-38
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• 2016

In this paper, zinc oxide nanoparticles (ZnO NPs) were synthesized using the sonochemical method, where equimolar amounts of zinc acetate dehydrate and sodium hydroxide were separately dissolved in deionized water, and then mixed for 30 min under magnetic stirring. The resultant white gel was sonicated for 60, 120, 180, 240, and 360 min with magnetic stirring. The obtained precipitates were centrifuged, repeatedly washed with ethanol to remove ionic impurities, and dried at 50 ℃ for 24 h. The formation of pure NPs was confirmed by X-ray diffraction, and their crystallinity and crystal phases were analyzed as well. Structural investigation was carried out by field-emission scanning electron microscopy (FE-SEM). The photocatalysis behavior of the ZnO NPs was investigated in a dark room under UV irradiation, using Rhodamine B. Spherical, rod, and flower-like ZnO NPs could be obtained by adjusting the sonication time, as observed by FE-SEM. The flower-like ZnO NPs exhibited excellent photocatalytic activity.

• Elastomers and Composites
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• v.36 no.3
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• pp.195-200
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• 2001

Ultraviolet photografting of acrylic acid onto low density polyethylene was characterized using XPS and contact angle measurement. Effects of surface modification at LDPE and aluminum on LDPE/Al laminate were also investigated. Contact angle decreased significantly at initial state arid tends to level off with increasing UV irradiation time. The improvement of hydrophilicity was due to the presence of acrylic acid on LDPE surface. Graft of acrylic acid onto LDPE was also identified from O1s/C1s ratios in XPS spectrum. Adhesion strength of LDPE-g-AAc/Al laminate showed about 30 times higher than LDPE/A1 system and it could be attributed to the increase of polarity of LDPE surface. Chemical treatment of Al surface using sulfuric acid/sodium dichromate also increased the adhesion strength of LDPE/Al laminate. Adhesion strength of LDPE/Al laminate decreased significantly under acetic acid.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.118-125
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• 2021

In this study Orostachys japonica A. Berger used is a medicinal herb that has long been used as a folk remedy for cancer treatment. In this study, the antioxidant efficacy of the ethyl acetate fraction of Orostachys japonica A. Berger was confirmed. The results of the Orostachys japonica A. Berge ethyl acetate fraction of antioxidant activity assays showed Antioxidant effect of Orostachys japonica A. Berger EtOAc fraction extract at 0.10 mg/mL was showed a DPPH radical scavenging rate of 78.54% and ABTS+ radical scavenging rate of 73.48%. Also, the toxicity result of Orostachys japonica A. Berger EtOAc fraction extracts using alternative experimental animal model zebrafish, confirmed a 100% the survival of the zebrafish embryo was shown that there was no coagulation and no hatching delay at all concentrations. also ROS generation induced by UV-B irradiation was confirmed that the fluorescence intensity decreased as a whole in all larvae treated with Orostachys japonica A. Berger EtOAc fraction extracts. In particular, it was confirmed that ROS generation was effectively suppressed by showing a 35.7% reduction rate compared to the positive control at a concentration of 3 ㎍/mL. These results were confirmed that Orostachys japonica A. Berger EtOAc fraction extracts has the possibility of application in the cosmetics field as a natural antioxidant.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.201-208
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• 2002

Staphylokinase is seldom formed by animal Staphylococcus aureus strains. In this study, 76(72.4%) of 105 Staph aureus strains isolated from bovine mastitis were found to produce a staphylokinase. These staphylokinase producing strains were tested for lysogenic conversion by means of delysogenization procedure and isolation of serotype B and F converting phages. By the application of delysogenization method comprised of UV irradiation and acriflavine treatment to 76 staphylokinase-positive strains, the delysogenized cells could be observed in 29(38.2%) of the strains and delysogenization rates in 16(55.2%) of 29 delysogenized strains were 0.9% or less. A total of 7 serological group F phages were isolated from 76 staphylokinase-positive strains, and these phages could be again divided into three groups by the immunity reaction. Of 7 serotype F phages, 2 were isolated from the original lysogenic strains producing colonies of delysogenized cells after delysogenizing treatments and 5 were isolated from strains in which delysogenized cells were not observed after delysogenizing treatments. Difference of sensitivities to serological group F phages between original lysogenic strains and strains from which delysogenized cells were not isolated after delysogenizing treatments was not observed These data suggest that staphylokinase production of the remaining 42 strains might be also mediated by lysogenic conversion.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.171-174
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• 2005

To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous Phase inside glass. In this study, Ag-doped $45SiO_2-24CaO-24Na_2O-4P_2O_5$ glasses were irradiated to strengthen by crystallization using femto-second laser pulse. UV/VIS, Spectroscope, XRD, nano-indenter and SEM etc. irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value$(4.4\~4.56{\ast}10-3Pa)$ of elastic modulus which related with strength of glass than values heat-treated samples and these are $1.2\~1.5$ times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.

• Elastomers and Composites
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• v.51 no.1
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• pp.49-55
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• 2016

Nanosized cobalt disulfide ($CoS_2$) particles were synthesized with 0.08 M cobalt chloride hexahydrate ($CoCl_2{\cdot}6H_2O$) and 0.2 M sodium thiosulfate pentahydrate ($Na_2S_2O_3{\cdot}5H_2O$) dissolved in distilled water under microwave irradiation. $[C_{60}]Fullerene-CoS_2$ nanocomposites were prepared with nanosized $CoS_2$ particles and [$C_{60}$]fullerene as heated by $700^{\circ}C$ for 2 h in an electric furnace. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified the heated $[C_{60}]fullerene-CoS_2$ nanocomposites. Heated $[C_{60}]fullerene-CoS_2$ nanocomposites were investigated the activity of photocatalytic degradation as a catalyst in various organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B with ultraviolet light at 254 nm by UV-vis spectrophotometer.