• Journal of the Korean Chemical Society
• /
• 제45권6호
• /
• pp.577-588
• /
• 2001

Eu doped YRO$_4$ (R=As, Nb, P, V) red phosphors were prepared by the combinatorial chemistry method. The quaternary material library of tetrahedron-type composition array was designed to investigate the luminescence of the host material under UV and VUV excitations (254, 147 nm). The photoluminescent characteristics of the samples were comparable to the commercially available red phosphors such as (Y, Gd)BO$_3$: $Eu^{3+}$ and Y$_2$O$_3$: In view of the luminescence yield, V rich region was found to be optimum under UV excitation. But the results under VUV excitation were different from those of UV excitation, the samples of the composition containing a large amount of P shows the highest luminescence. Especially, higher luminescence was obtained in $Y_{0.9}$(A$S_{0.06}$N$B_{0.06}P_{0.83}V_{0.06}$) O$_4$: $Eu_{0.1}$ phosphors than commercial (Y, Gd)BO$_3$red phosphors under 147 nm excitation.

• Journal of the Korean Chemical Society
• /
• 제50권3호
• /
• pp.237-242
• /
• 2006

Nowadays, LEDs has been applied to the luminescent devices of various fields because of the invention of high efficient blue chip. Recently, especially, the white LEDs composed of InGaN blue chips and a yellow phosphor (YAG:Ce3+) have been investigated extensively. With the exception of YAG:Ce3+ phosphor, however, there are no reports on yellow phosphor that has significant emission in the 450~470 nm excitation range and this LED system is the rather low color rendering index due to their using two wavelength. Hence, we have attempted to synthesize thiogallate phosphors that efficiently under the long wavelength excitation range in the present case. Among those phosphors, we have synthesized Sr2Ga2S5:Eu2+ phosphor by change the host material of SrGa2S4:Eu2+ which is well known phosphor and we investigated the luminescent properties. In order to obtain the harmlessness and simplification of the synthesis process, sulfide materials and mixture gas of 5 % H2/95 % N2 were used instead of the CS2 or H2S gas. The prepared phosphor shows the yellow color peaking at the 550 nm wavelength and it possible to emit efficiently under the broad excitation band in the range of 300~500 nm. And this phosphor shows high luminescent intensity more than 110 % in comparison with commercial YAG:Ce3+ phosphor and it can be applied for UV LED due to excitation property in UV region.

• Clinical and Experimental Reproductive Medicine
• /
• 제29권2호
• /
• pp.105-115
• /
• 2002

Objective : To evaluate the effects of the reactive oxygen species (ROS) generated with a xanthine (X) and xanthine oxidase (XO) system on sperm function, the change of sperm characteristics, lipid peroxidation, and DNA fragmentation in bovine spermatozoa. Materials and Methods: ROS were produced using a combination of 1000 uM X and 50 mU/ml XO. The ROS scavengers: superoxide dismu tase (SOD) (200 U/ml) and catalase (500 U/ml) were also tested. Spermatozoa were incubated for 2 hours in BWW medium with a combination of X-XO supplemented with or without ROS scavengers at $37^{circ}C$ under 5% $CO_2$ incubator. Sperm movement characteristics by CASA (computer-aided sperm analysis), HOST (hypoosmotic swelling test), Caionophore induced acrosome reaction, malondialdehyde formation for the analysis of lipid peroxidation, the percentage of DNA fragmentation using the method of TdT-mediated nick end labelling (TUNEL) by flow cytometry were determined after 2 hours incubation. Results: The action of ROS on bovine spermatozoa resulted in a decreased in capacity for sperm motility, Ca-ionophore induced acrosome reaction and membrane integrity, an increased in malondialdehyde formation and the percentage of sperm with DNA fragmentation. In the effects of antioxidant, catalase completely alleviated the toxic effects induced by the ROS in terms of sperm function and characteristics, however SOD exhibited no capacity to reduce the toxic effects. Conclusion: The ROS can induce significant damages to sperm functions and characteristics. The useful ROS scavengers can minimized the defects of sperm function and various damages of spermatozoa.

• The Journal of the Petrological Society of Korea
• /
• 제14권3호
• /
• pp.141-148
• /
• 2005

Lead isotopic compositions are analyzed from the sulfide minerals of the Yeonhwa, Janggun and Uljin deposits and from host limestone, intrusives, and basement rocks to reveal the source of Pb in these deposits. In the $^{206}Pb/^{204}Pb$ vs $^{207}Pb/^{204}Pb$ plot, Galenas from the Yeonhwa mine display relatively well defined positive linear array, similar to the Precambrian basement rocks of the Korean peninsula. A galena sample from the Uljin mine, Janggun limestone and the basement rocks also follow the variation of Yeonhwa mine. However, ore minerals from the Janggun mine, having relatively low $^{206}Pb/^{204}Pb$ values, reveal offset from such trend toward lower $^{207}Pb/^{204}Pb$ values. Considering the fact that Mesozoic igneous rocks and ores within the Gyeongsang basin display considerably lower $^{207}Pb/^{204}Pb$ values than basement rocks of the Korean peninsula, the deviation of Janggun ore minerals can be interpreted as to reflect mixing between leads from old continental crustal materials and from Mesozoic igneous rocks with more mantle signature. The lead of the Yeonhwa and Uljin mine, following trend of Precambrian basement rather well, seems to have been originated mostly from such basement. However, regarding that they occupy low $^{207}Pb/^{204}Pb$ side of the variation trend of the basement, the possibility of having some leads derived from the Mesozoic igneous rocks cannot be excluded.

• Economic and Environmental Geology
• /
• 제30권2호
• /
• pp.81-87
• /
• 1997

Chonnam and Kyongsang clay alteration areas are distributed in volcanic fields of the Yuchon Group in late Cretaceous period. The host rock of the Chonnam alteration area is generally acidic and that of the Kyongsang alteration area is acidic to dominantly intermediate volcanics. The important difference of two alteration areas is source of fluid; the Chonnam alteration area is characterized by dominantly meteoric water and the Kyongsang alteration area is characterized by dominantly magmatic water. Accordingly, the high temperature minerals such as pyrophyllite and andalusite, and boron bearing minerals such as dumortierite and tourmaline are common in the Kyongsang alteration area. In contrast to this, the lower temperature minerals such as kaolin and alunite are common in the Chonnam alteration area. The mineralogical difference of two alteration areas were depended on the difference of the formation temperature of clay deposits. The other important geochemical difference is the chemistry of hydrothermal solution such as pH. The alteration of "acid-sulfate type" with alteration mineral assemblage of alunite-kaolin-quartz is dominant in the Chonnam alteration area, which was caused by the attack of strong acid and acid solution. In contrast to this, the that of "quartz-sericite type" with the mineral assemblage of sericite-quartz is dominant in the Kyongsang alteration area, which was caused by the attack of neutral or weak acid solution. Also, the Kyongsang and Chonnam alteration areas show the difference in structural setting; the Chonnam alteration area is commonly associated with silicic domes and the Kyongsang alteration area is commonly associated with calderas.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권4호
• /
• pp.1903-1907
• /
• 2016

Background: Studies of effects of IL-1 polymorphisms, CYP2C19 genotype together with antibiotic resistance for H. pylori eradication are rare worldwide. The present study was designed to evaluate efficacy of 10-day sequential therapy (SQT) and 14-day standard triple therapy (STT) with four- times-daily dosing of amoxicillin for H. pylori eradication related to these important host and bacterial factors in Thailand. Materials and Methods: This prospective randomized study was performed during March 2015 to January 2016. H. pylori infected gastritis patients were randomized to receive 10-day sequential therapy and 14-day standard triple therapy. CYP2C19 genotyping, IL1 polymorphism (IL-1B and IL-1RN genotypes) and antibiotic susceptibility tests were performed in all patients. 13C-UBT was conducted to confirm H. pylori eradication at least 4 weeks after treatment. Results: A total of 100 patients (33 males and 67 females, mean age=51.1 years) were enrolled. Eradication rate by PP analysis was 97.9% (47/48) with the 10-day SQT regimen and 87.8% (43/49) with 14-day STT regimen (97.9% vs 87.8%; p-value=0.053). Antibiotic susceptibility testing demonstrated 45% resistance to metronidazole, 14.8% to clarithromycin, and 24.1% to levofloxacin. CYP2C19 genotyping revealed 44.9% RM, 49% IM and 6.1% PM. IL-1B and IL-1RN genotypes were demonstrated as 21.4% for CC, 48.1% for TC, 36.8% for TT, 72.7% for 1/1, and 21.2% for 1/2 genotypes, respectively. The 10-day SQT regimen provided 100% eradication in patients with clarithromycin or dual clarithromycin and levofloxacin H. pylori resistant strains. Moreover, the 10-day SQT regimen resulted in a 100% eradication rate in all patients with CYP2C19 genotype RM and almost type of IL-1B (TC and TT) and IL1-RN genotypes ( 1/2 and other). Conclusions: Treatment with 10-day sequential therapy is highly effective for H. pylori eradication regardless of the effects of clarithromycin resistance, dual clarithromycin and levofloxacin resistance, CYP2C19 genotype, IL-1B and IL1-RN genetic polymorphisms and can be used as effective first line therapy in Thailand.

• Journal of Conservation Science
• /
• 제33권4호
• /
• pp.225-239
• /
• 2017

This study aimed to investigate the chemical properties and production techniques for white wares from the Gwirae-1ri 3rd, Songok-3ri 2nd kiln sites in Kangwon Wonju regions. Further, another aim was to determine the correlation among the materials used to produce the white wares. The analysis of white wares in Kangwon Wonju regions produced the following results. The excavated white wares were analyzed using the Seger formula, and all the samples showed similar clay sources ($RO_2:4.33-5.82$, $RO+R_2O:0.32-0.43$) and glaze sources. Moreover, the white wares were made of host rocks of the same geological origin, according to the results of the rare earth elements analysis. When the crystalline phases of the white wares were investigated via the XRD analysis, quartz and mullite were found in all the samples, and their proportions were similar to each other. Although the firing temperatures for the samples were different, most were fired at a temperature below $1,200^{\circ}C$, with some being fired at temperatures as low as $1,000{\pm}20^{\circ}C$.

• The Journal of Internal Korean Medicine
• /
• 제25권4호
• /
• pp.289-299
• /
• 2004

Background : Although the pathophysiology of asthma has been reported, its mechanism has not been fully elucidated. The mast cell is an effector cells in allergic inflammation and secretes a number of chemokines. Chemokines are important for the recruitment of leukocytes to sites of infection, which is essential in host defense. Chemokines also contribute to the pathogenesis of several disorders such as asthma, chronic bronchitis, atopic dermatitis, allergic rhinitis, and rheumatoid arthritis. Objective : In this study, the aim was to identify the effect of Baekryunchihyo-tang(白蓮治哮湯) on expression of chemokines. This was examined by RT-PCR using the human mast cell line (HMC-l) Materials and Methods : HMC-l cells were used, which is known to secrete and express chemokines. In order to investigate the protective effect of Baekryunchihyo-tang(白蓮治哮湯), HMC-l cells were incubated with pretreatment of Baekryunchihyo-tang(白蓮治哮湯) for 24 hrs. RT-PCR analyses of chemokine genes of cells pretreated with Baekryunchihyo-tang(白蓮治哮湯) showed that expressions of IL-8, $MIP-l{\beta}$, and RANTES genes in these cells were lower and $MIP-l{\alpha}$ showed a similar pattern compared to the calcium ionophore-treated group. In addition, cell cytotoxicity concentration measurements were performed by MTT assay method. Results : After stimulation with 1 uM calcium ionophore A23178 for 2 hrs, IL-8, major one of CXC chemokines, was highly expressed, and expression of $MIP-l{\beta}$ and RANTES (CC chemokines) increased, while expression of $MIP-l{\alpha}$ did not change. The cell cytotoxicity of Baekryunchihyo-tang(白蓮治哮湯) with treatments at various concentrations and times was not observed, respectively. Conclusion : This study suggests that Baekryunchihyo-tang(白蓮治哮湯) has dose-dependent effects on mRNA expression of IL-8(CXC chemokines), $MIP-l{\beta}$ and RANTES(CC chemokines) in human mast cellline(HMC-l). So these herbal medicines may inhibit the inflammatory process of asthma. Advanced studies are required to investigate the mechanism of inhibition by herbal medicine in the asthma model. This study provides basic data on the possibility of the clinical treatment of Baekryunchihyo-tang(白蓮治哮湯) for allergic disorders.

• Korean Journal of Veterinary Service
• /
• 제38권4호
• /
• pp.233-239
• /
• 2015

Both Q-fever and Toxoplasmosis are zoonosis. Q-fever occurs due to intracellular bacteria, while Toxoplasmosis is created by protozoan. Both of them have a wide range of host including livestock and wild animals and occur sporadically all over in the world. In this study, seroprevalence of Q-fever and Toxoplasmosis was investigated on cows bred in the area of Seoul where there was a fairly high possibility to occur, while vaccine was not used in Korea. As for experiment materials, cattle blood collected from 190 cows from February to September in 2014 was used ELISA. According to the result, there was a positive reaction on Q-fever from 18 cows out of total 190 cows (9.5%) and on Toxoplasmosis from 32 cows (16.8%). Seroprevalence of both diseases per age was turned out to be negative for those aged less than 2. In addition, it was shown to be positive on 4 cows out of 87 (4.6%) cows aged from 3 to 5, on 7 cows out of 30 cows (23.3%) aged from 6 to 7. Finally, it was shown to be positive on 7 cows out of 17 cows (41.2%) aged 8 or above. Toxoplasmosis was turned out to be positive on 1 cow out of 56 cows (1.8%) aged less than 2, on 6 cows out of 87 cows (6.9%) aged from 3 to 5, on 17 cows out of 30 cows (56.7%) aged from 6 to 7. In addition, it was turned out to be 8 cows out of 17 cows (47.1%) aged 8 or above. Seroprevalence of both diseases was turned out to be higher as age increased. Therefore, it seems that a wide range of investigation on the entire disease spreaders as well as livestock is required since infection of Q-fever and Toxoplasmosis, types of zoonosis, has continuously occurred, and the number of insects, wild animals, and stray animals serving as a role of spreading diseases by changes in seasons and environments has been gradually increasing in Korea.

• Korean Journal of Head & Neck Oncology
• /
• 제19권2호
• /
• pp.148-157
• /
• 2003

Background and Objectives: Individual genetic susceptibilities to chemical carcinogens have been recognized as a major important host factors in human cancers. The cytochrome P450 family (CYPs) and glutathione S-transferase(GST) have been reported to be associated with risks to the smoking-related human cancers. Inactivation of tumor suppressor genes like p53 playa key role in tumor progression. The purpose of this study is to demonstrate an association between p53 overexpression and the prevalence of the genetic polymorphisms of CYP1A1 and GSTs in Korean head and neck squamous cell carcinoma (HNSCC). Materials and Methods: The polymorphisms of CYPIA1 and GSTs were analyzed by PCR and PCR-RFLP in 98 Korean head and neck squamous cell carcinoma patients. The expression of p53 was analyzed by immunohistochemistry with anti-p53 Ab (DO7). Results: Overexpression of p53 detected in 45.9% of HNSCC. The odds ratio for p53 overexpression in GSTM1(-), GSTT1(-), GSTP1(val/val) and CYP1A1(val/val) were 1.53, 1.83, 1.17 and 1.47, respectively. Among the combined genotypes, the odds ratio of the CYP1A1 val/val, GSTM1 (-), CYP1A1 val/val, GSTT1(-), and CYP1A1 val/val, GSTT1(-) were 2.0, 2.34 and 4.68, respectively. Conclusion: Based on our results, it might be suggested that p53 overexpression is slightly increased in GSTM1(-), GSTT1(-), GSTP1 val/val, CYP1A1 val/val genotypes. The further study is needed to evaluate the relationship and mechanism between the p53 overexpression and the specific CYP1A1 and GSTs genotypes.