• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.11
• /
• pp.4459-4463
• /
• 2014

Background: Gastric cancer is the second leading cause of cancer-related deaths worldwide and infection with H. pylori is considered essential for its development. Helicobacter pylori infects more than 50% of the world's population with higher prevalence in developing countries than developed countries. The prevalence of H. pylori varies in different societies and geographical locations. The objectives of this study were to estimate the seroprevalence and determine the risk factors of H. pylori infection in dyspeptic patents in Ethiopia. Materials and Methods: A cross-sectional study involving 209 dyspeptic patients was carried out from February 15 to April 30, 2013. Five to ten ml venous blood was collected from each dyspeptic patient and analyzed for detection of Helicobacter pylori immunoglobulin (IgG). The socio-demographic characteristic, hygienic practices, alcohol consumption, sources of drinking water and types of latrine were also obtained with a pre-tested questionnaire. Results: The overall seroprevalence of Helicobacter pylori was 72.2%. There was statistically significant difference in the prevalence of H. pylori among age groups (p=0.02). Seroprevalence of H. pylori was higher in those patients who used unprotected surface water (76.4%) than those with access to piped tap water (65.9%). There was also statistically significant differences in prevalence of H. pylori with the habit of hand washing before meal (p=0.01) and alcohol consumption (p=0.001). Conclusions: The prevalence of H. pylori was high in the study area and increased with age of dyspeptic patients. Alcohol consumption and the type of drinking water are risk factors that have associations with the prevalence of H. pylori. Molecular epidemiological techniques can show a true picture of H. pylori and improvement in the drinking water quality is recommended.

• Carbon letters
• /
• v.22
• /
• pp.1-13
• /
• 2017

Porous materials play a vital role in science and technology. The ability to control their pore structures at the atomic, molecular, and nanometer scales enable interactions with atoms, ions and molecules to occur throughout the bulk of the material, for practical applications. Three-dimensional (3D) porous carbon-based materials (e.g., graphene aerogels/hydrogels, sponges and foams) made of graphene or graphene oxide-based networks have attracted considerable attention because they offer low density, high porosity, large surface area, excellent electrical conductivity and stable mechanical properties. Water pollution and associated environmental issues have become a hot topic in recent years. Rapid industrialization has led to a massive increase in the amount of wastewater that industries discharge into the environment. Water pollution is caused by oil spills, heavy metals, dyes, and organic compounds released by industry, as well as via unpredictable accidents. In addition, water pollution is also caused by radionuclides released by nuclear disasters or leakage. This review presents an overview of the state-of-the-art synthesis methodologies of 3D porous graphene materials and highlights their synthesis for environmental applications. The various synthetic methods used to prepare these 3D materials are discussed, particularly template-free self-assembly methods, and template-directed methods. Some key results are summarized, where 3D graphene materials have been used for the adsorption of dyes, heavy metals, and radioactive materials from polluted environments.

• BMB Reports
• /
• v.49 no.12
• /
• pp.681-686
• /
• 2016

Fructose 1,6-bisphosphate aldolase (FBA) is important for both glycolysis and gluconeogenesis in life. Class II (zinc dependent) FBA is an attractive target for the development of antibiotics against protozoa, bacteria, and fungi, and is also widely used to produce various high-value stereoisomers in the chemical and pharmaceutical industry. In this study, the crystal structures of class II Escherichia coli FBA (EcFBA) were determined from four different crystals, with resolutions between $1.8{\AA}$ and $2.0{\AA}$. Native EcFBA structures showed two separate sites of Zn1 (interior position) and Zn2 (active site surface position) for $Zn^{2+}$ ion. Citrate and TRIS bound EcFBA structures showed $Zn^{2+}$ position exclusively at Zn2. Crystallographic snapshots of EcFBA structures with and without ligand binding proposed the rationale of metal shift at the active site, which might be a hidden mechanism to keep the trace metal cofactor $Zn^{2+}$ within EcFBA without losing it.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.242-242
• /
• 2016

Magnetite, Fe3O4, is a ferrimagnet with a cubic inverse spinel structure and exhibits a metal-insulator, Verwey, transition at about 120 K.[1] It is predicted to possess as half-metallic nature, 100% spin polarization, and high Curie temperature (850 K). Cobalt ferrite is one of the most important members of the ferrite family, which is characterized by its high coercivity, moderate magnetization and very high magnetocrystalline anisotropy. It has been reported that the CoFe2O4/Fe3O4 bilayers represent an unusual exchange-coupled system whose properties are due to the nature of the oxide-oxide super-exchange interactions at the interface [2]. In order to evaluate the effect of interface interactions on magnetic and transport properties of ferrite and cobalt ferrite, the CoFe2O4/Fe3O4 superlattices on MgO (100) substrate have been fabricated by molecular beam epitaxy (MBE) with the wave lengths of 50, and $200{\AA}$, called $25{\AA}/25{\AA}$ and $100{\AA}/100{\AA}$, respectively. Streaky RHEED patterns in sample $25{\AA}/25{\AA}$ indicate a very smooth surface and interface between layers. HR-TEM image show the good crystalline of sample $25{\AA}/25{\AA}$. Interestingly, magnetization curves showed a strong antiferromagnetic order, which was formed at the interfaces.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.179-179
• /
• 2016

A radio-frequency (RF) Inductively Coupled Plasma (ICP) torch system was used for boron-nitride nano-tube (BNNT) synthesis. Because of electrodeless plasma generation, no electrode pollution and effective heating transfer during nano-material synthesis can be realized. For stable plasma generation, argon and nitrogen gases were injected with 60 kW grid power in the difference pressure from 200 Torr to 630 Torr. Varying hydrogen gas flow rate from 0 to 20 slpm, the electrical and optical plasma properties were investigated. Through the spectroscopic analysis of atomic argon line, hydrogen line and nitrogen molecular band, we investigated the plasma electron excitation temperature, gas temperature and electron density. Based on the plasma characterization, we performed the synthesis of BNNT by inserting 0.5~1 um hexagonal-boron nitride (h-BN) powder into the plasma. We analysis the structure characterization of BNNT by SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy), also grasp the ingredient of BNNT by EELS (Electron Energy Loss Spectroscopy) and Raman spectroscopy. We treated bundles of BNNT with the atmospheric pressure plasma, so that we grow the surface morphology in the water attachment of BNNT. We reduce the advancing contact angle to purity bundles of BNNT.

• BMB Reports
• /
• v.48 no.1
• /
• pp.42-47
• /
• 2015

Streptococcus mutans is frequently associated with dental caries. Bacterial fermentation of food debris generates an acidic environment on the tooth surface, ultimately resulting in tooth deterioration. Therefore, various mouthwashes have been used to reduce and prevent Streptococcus mutans. The aim of this study was to evaluate the antimicrobial activities of 4 commercial mouthwashes and those of 10% and 20% ethanol solutions (formula A, B, C, D, E and F) against Streptococcus mutans using biofilm and planktonic methods. The range of reduction in the viable cell count of Streptococcus mutans as estimated by the biofilm and planktonic methods was 0.05-5.51 log ($P{\leq}0.01$) and 1.23-7.51 log ($P{\leq}0.001$) compared with the negative control, respectively, indicating that the planktonic method had a stronger antibacterial effect against S. mutans. Among the tested formulations, formula A (Garglin $regular^{(R)}$ mouthwash) was the most effective against Streptococcus mutans ($P{\leq}0.001$).

• Polymer(Korea)
• /
• v.27 no.4
• /
• pp.293-298
• /
• 2003

The development of the crystalline structure of poly(trimethylene terephthalate) (PTT) in a confined geometry was investigated with optical microscope, small angle light scattering, and X-ray diffraction. The rejected distance, which was represented in terms of the parameter $\delta$, played an important role in determining the morphological patterns of poly (ethylene terethphalate) (PET/PTT) blend. In case of stepwise crystallization, the crystallization of PTT commenced in the interspherulitic region between the grown PET crystals and proceeded until the interspherulitic space was filled with the PTT crystals. The spherulitic surface of the PET crtstals acted as the nucleation sites where the PTT molecules preferentially crystallized, leading to the formation of transcrystalline structure. As a result, a mixed morphological pattern was observed in the PTT-rich phase: one was a typical spherulitic texture and the other was a transcrystalline texture. Some of the molecular conformations of PTT, which could adopt in the absence of the space limitation, were probably forbidden in the interlamellar and/or interfibrillar regions of the PET spherulite. This constraint was responsible for difference in the crystallization and melting behavior of PTT between the intra and interspheulitic regions of PET.

• Korean Journal Plant Pathology
• /
• v.13 no.3
• /
• pp.172-178
• /
• 1997

Xanthmonas campestris pv. campestris, causal agent of Black rot of crucifers, were isolated and identified from crucifer host. In order to determine the characters of X. c. pv. campestris associated with pathogenicity, Tn5 mutagenesis was carried out by conjugating with E. coli pJB4J1. Transconjugants were plate- assayed for missing cellulase, protease and amylase activity. A cellulase negative mutant was selected and tested for pathogenicity. Light microscopy and Scanning electron microscopy revealed that substomatal tissues were colonized by mutant, but was far less extensive than those by wild type. Stomatal surface and substomatal tissue appeared to have degraded by only wild type in 24 hrs and progression of pathogenesis was distinct in 48 hrs. In 6 days, wild type proliferated well in the tissue facilitated by cellulase activity. As a result, cellulase was determined as the important factor in pathogenesis.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.34.1-34.1
• /
• 2013

Interstellar ices (e.g., $H_2O$, $CO_2$, and CO ices) are formed on the surface of dust grains in dense molecular clouds. In a near-infrared spectrum, we can observe deep absorption features particularly due to $H_2O$ ice at $3.05{\mu}m$ and $CO_2$ ice at $4.27{\mu}m$. These interstellar ices have many pieces of information on the interstellar environment. Among various ices, $CO_2$ ice is one of the most important ones as a probe of the interstellar environment. That is because $CO_2$ ice is a secondary product unlike $H_2O$ and CO ices which are primarily formed on dust grains. Past studies for $CO_2$ ice in nearby galaxies were performed only for the galactic center in a few galaxies. In order to utilize the information from $CO_2$ ice effectively, it is valuable to perform mapping observations of ices on a galactic scale. With AKARI, we obtain the spatially-resolved near-infrared ($2.5-5.0{\mu}m$) spectra for the central ~1 kpc region of the nearby starburst galaxy M 82. These spectra clearly show the absorption features due to interstellar $H_2O$ and $CO_2$ ices, and we created their column density maps. As a result, we find that the spatial distribution of $H_2O$ ice is significantly different from that of $CO_2$ ice; $H_2O$ ice is widely distributed, while $CO_2$ ice is concentrated near the galactic center. Our result for the first time reveals spatial variations in $CO_2/H_2O$ ice abundance ratio on a galactic scale, suggesting that the ice-forming interstellar environment changes within a galaxy. In this presentation, we discuss the cause of the variations in the ice abundance ratio.

• Journal of Environmental Health Sciences
• /
• v.32 no.3
• /
• pp.227-234
• /
• 2006

There has been increasing concern in recent years about the occurrence, fate and toxicity of pharmaceutical products in aquatic environment. Although these compounds have been detected in a wide variety of environmental samples including sewage effluent, surface waters, ground water and drinking water, their concentrations generally range from the low ppt to ppb levels. It is therefore often thought to be unlikely that pharmaceuticals will have a detrimental effect on the environment. This study was conducted to determine the endocrine disruption effects of the several pharmaceutical residues in water using adult Japanese medaka (Oryzias latipes). The common antibiotics were used sulfa durgs (sulfamethoxazole and sulfamethazine) and tetracycline drugs (oxytetracycline and tetracycline). Positive control that was induced Vtg (vitellogenin) in male fish was used $17\beta$-estradiol. Vtg was qualified and quantified through Western blotting and ELISA. After SDS gel electrophoresis, the dominant protein band was identified to molecular weight approximately 205 kDa in whole body samples of vitellogenic female. In female medaka exposed to $17\beta$estradiol, there was no significant difference in total protein induction. In contrast, three to five day exposure of male fish to $17\beta$-estradiol resulted in more than 60.0% increase of total protein compared to that of control males (p<0.01). In case of antibiotics, female fish didn't show significant difference, but male fish was showed significant difference. In addition, Vtg induction in male fish was observed with all the test chemicals. On concentrations greater than 0.1 ppm of sulfamethoxazole, 1 ppm of sulfamethazine, 1 ppm of oxytetracycline and 20 ppm of tetracycline, Vtg induction was increased in a dose response manner. This study is one of the early reports suggesting potential endocrine disruption mechanism of antibiotic pharmaceutical products in aquatic ecosystem. Although the effect concentrations obtained from this study were high as unrealistically as in environments, it is endocrine disruption that we should be considered as one of the important consequences of pharmaceutical contamination at water environment, and warrants due attention in future researches.