• BMB Reports
• /
• v.40 no.6
• /
• pp.1028-1038
• /
• 2007

Human plasma Hp is classified as 1-1, 2-1, and 2-2. They are inherited from two alleles Hp 1 and Hp 2, but there is only Hp 1 in almost all the animal species. Hp 2-2 molecule is extremely large and heterogeneous associated with the development of inflammatory-related diseases. In this study, we expressed entire bovine Hp in E. coli as a $\alpha\beta$ linear form. Interestingly, the antibodies prepared against this form could recognize the subunit of native Hp. In stead of a complicated column method, the antibody was able to isolate bovine Hp via immunoaffinity and gelfiltration columns. The isolated Hp is polymeric containing two major molecular forms (660 and 730 kDa). Their size and hemoglobin binding complex are significantly larger than that of human Hp 2-2. The amino-acid sequence deducted from the nucleotide sequence is similar to human Hp 2 containing a tandem repeat over the $\alpha$ chain. Thus, the Hp 2 allele is not unique in human. We also found that there is one additional -SH group (Cys-97) in bovine $\alpha$ chain with a total of 8 -SH groups, which may be responsible for the overall polymeric structure that is markedly different from human Hp 2-2. The significance of the finding and its relationship to structural evolution are also discussed.

• YAKHAK HOEJI
• /
• v.39 no.4
• /
• pp.373-379
• /
• 1995

Coupling of tetracycline (Tc) to dithiocarbamate chitosan(DTCC) via chelate bond was carried out in the presence of Mg (II) ion by one- and two-bath process. In one-bath process, DTCC was treated with Mg(II)-Tc solution. In two-bath process, DTCC was treated with Mg(II) to produce DTCCMg(II), which was isolated and treated in turn with Tc solution. The effect of pH and temperature on binding of Tc, was investigated varying the pH of the solution from 2.6 to 3.2 at 10 and $30^{\circ}C$. Binding of Tc was not affected greatly by such variations in pH and temperature. Amount of Tc bound to 1 gm of matrix reached to 180 mg. Release of Tc from DTCC-Mg(II)-Tc was investigated by batch and flow method, and the amount of Tc released against time followed by flow method exhibited near linear relationship. DTCC-Mg(II)-Tc showed very prolonged antimicrobial activity compared to that of free Tc when it was tested against Escherichia coli TG-1 and Bacillus subtilis NA-1.

• Journal of the Korean Ceramic Society
• /
• v.32 no.1
• /
• pp.17-24
• /
• 1995

The TEA complex polymeric sol was prepared by the alkoxide sol-gel method. The purpsoe of this experiment was to vefity the particle shape in the sol from the investigation of the rheological properties. TEA retarded hydrolysis rate by the reaction with alkoxide enough to make a stable transparent sol in the wide range of composition. From the results of the viscosity change with time, the optimum mole ratio for spinning was selected as 0.5 mole of TEA, 3 mole of H2O and the optimum viscosity was 104 cPs. The rheological behavior of the sol showed that the particle shape in the sol was linear, which was adequate for fiber drawing.

• Preventive Nutrition and Food Science
• /
• v.6 no.4
• /
• pp.247-252
• /
• 2001

The need to determine the permeability of organic vapors to polymeric films such as aromas, flavors, etc. has significantly increased in the food industry because of preservation and safety issues along with migration problems. However, due to the complex nature of the permeation process, there have been few investigations compared to nonorganic compounds. In this paper, we review the history of permeability studies and typical methods of permeability measurement such as the isostatic method and quasi-isostatic method for organic vapors. New instrumental developments and significant findings are also introduced and discussed.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.1
• /
• pp.85-93
• /
• 2011

The structural components of microorganism are quite related to the toxin and environmental conditions. The vegetative and dormant cells are quite affected by the physical and chemical environments to survive and they will be dormant when they are in the extreme environment. The mechanism to activate the microorganisms however, is not well defined yet in the area of activation state and sporulation state through the analysis of EPS. Other than that even the main mechanism of prior to acquisition of analysis values is not well understood. Therefore, what kind of specific environment to affect the activation and sporulation will be discussed through the analysis of the extracellular polymeric substances(EPS). EPS are a high molecular weight mixture of polymers presenting both outside of cells and interior of microbial aggregates. They are a major complex materials in microbial aggregation for sustaining them together in a three dimensional matrix. Three commonly used extraction methods were applied to this study their effectiveness and quantification in extracting EPS from several Bacillus microorganisms and activated sludge. Three extraction methods used for this study are regular centrifugation with formaldehyde (RCF), Steaming, and EDTA extraction. The results of EPS contents such as the quantitative proteins, carbohydrates and the ratio of protein versus carbohydrate from the several species with the several specific methods showed in this research. This study aims to get comparable results of the quantitative production of EPS and the effectiveness of sedimentation for Bacillus microorganisms and activated sludge from several wastewater treatment plans. The results revealed that the protein amount extracted was the highest by the Steaming method of three extraction methods before sporulation and the carbohydrate amount extracted was the highest by the RCA method of three extraction methods after sporulation. The higher amount of protein compared with carbohydrate from Bacillus microorganisms affected higher sedimentation efficiency, however it could not be found the relation between the EPS production and sedimentation efficiency for the activated sludge.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.12
• /
• pp.1063-1068
• /
• 2000

Water treeing in underground distribution power cable is not easy to observe by nondestructive method and it has very complex patterns. This study describes the principles and practices of a continuous observation of initiation and growth of tree in polymeric insulation material using an image measurement technique. Using this technique we could observe water tree and the growing process of electrical tree due to the water tree and the growing process of electrical tree due to the water tree. All of these growing process is analyzed quantitatively by image measurement program composed of borland c++. We fabricated the thin film type specimen to observe water tree easier and also the needle electrode was prepared by etching method using electrolytes. Initiation and the growth of three was observed somewhat different depending on the applied voltage and the water electrode. AgNO$_3$solution electrode accelerates the initiation and the growth of water tree, compared to those of distilled water electrode. The water and the electrical tree occurred by water tree has discontinuous growth characteristic.

• Resources Recycling
• /
• v.7 no.4
• /
• pp.64-75
• /
• 1998

The purpose of this study is to produce high putity composite powder composed of Fe-oxide, Mn-oxide and Mn-ferrite having superior homogencity in composition and particle size distribution by co-roasting process. Binary component metal (Fe, Mn) chloride solutions were produced by dissolving mill scale and ferro-mangancse alloy in hydrochloric acid. These chloride solutions contained the impurities such as SiO$_{2}$, P, Al, Ca and Na, which were originated from the Fe/Mn source materials. The neutralization and polymeric coagulant method were adoped to refine the hydrochloric liquor. When pH is far below the isoelectric point (pH 2-3), the SiO$_{2}$ was the most effectively reduced element, while other impurities remained unchanged. By increasing pH above 3, most of the impurities could be reduced effectively due to the coprecipitation reaction. The polymeric coagulants such as poly vinyl alcohol, resin amine and ammonium molybdate were found to have no effect on the spray roaster designed by the authors. The produced oxide powders were confirmed to be mixtures of Fe-oxide, Mn-oxide and mn-ferrite. the powders were homogeneously mixed and the particle size increased sleeply with increasing co-roasting temperature.

• Membrane Journal
• /
• v.24 no.6
• /
• pp.472-483
• /
• 2014

This study is preparation of microporous membranes by using macrocyclic metal ion complexes and extended cage complexes. It is a more favorable way to existing methods because polymer and metal ion-ligand complex system provides a fine control over the phase transition behavior. Chemical functionalization of the polar surface can be obtained. Metal-templated condensation of cyclohexanedione dioxime, hydroxyphenylboronic acid in the presence of metal salts proceeds cleanly in methanol to furnish the metal clathrochelate complexes. Organic/inorganic hybrid membranes were prepared with polyethersulfone (PES), polyvinylpyrrolidone (PVP), ethyleneglycol butyl ether (BE), metal clathrochelate s and DMF by using nonsolvent induced phase inversion method. The structure of membranes was characterized with scanning electron microscopy (SEM) and microflow permporometer. The addition of Fe(II) clathrochelate complex with p-hydroxyphenyl group leads to changes of membrane morphology such as narrow mean pore size distribution, increase of surface pore density and decrease of the largest pore size.

• Journal of Adhesion and Interface
• /
• v.24 no.4
• /
• pp.136-142
• /
• 2023

In this study, TEOS was used as a silica source, and a triblock copolymer (P123) was used as a template to produce mesoporous silica with a well-ordered hexagonal mesopore array through a self-assembly method and hydrothermal process under acidic condition. (Surfactant-extracted SBA-15). Surfactant-extracted SBA-15 showed the particle shape of a short rod with a size of approximately 980 nm. The surface area and pore diameter were 730 m²g^-1 and 70.8 Å, respectively. Meanwhile, aminosilane (3-aminopropyltriethoxysilane, APTES) was grafted into the mesopores using a post-synthesis method. Mesoporous silica (APTES-SBA-15) modified with aminosilane had a well-ordered pore structure (p6mm) and well-maintained the particle shape of short rods. The surface area and pore diameter of APTES-SBA-15 decreased to 350 m²g^-1 and 60.7 Å, respectively. APTES-modified mesoporous silica was treated with a solution of rare earth metal ions (Eu³⁺, Tb³⁺) to synthesize a mesoporous silica material in which rare earth metal complexes were introduced into the mesopores. (Eu/APTES-SBA-15, Tb/APTES-SBA-15) These materials exhibited characteristic photoluminescence spectra by λ_ex=250 nm. (⁵D₄→⁷F₅ (543.5 nm), ⁵D₄→⁷F₄ (583.5 nm), ⁵D₄→⁷F₃ (620.2 nm) transitions for Tb/APTES-SBA-15; ⁵D₀→⁷F₀ (577.7 nm), ⁵D₀→⁷F₁ (592.0 nm), ⁵D₀→⁷F₂ (614.9 nm), ⁵D₀→⁷F₃ (650.3 nm) and ⁵D₀→⁷F₄ (698.5 nm) transitions for Eu/APTES-SBA-15)

• Korean Journal of Materials Research
• /
• v.27 no.12
• /
• pp.688-694
• /
• 2017

Porous materials such as polymeric foam are widely adopted in engineering and biomedical fields. Porous materials often exhibit complex nonlinear behaviors and are sensitive to material and environmental factors including cell size and shape, amount of porosity, and temperature, which are influenced by the type of base materials, reinforcements, method of fabrication, etc. Hence, the material characteristics of porous materials such as compressive stress-strain behavior and void volume fraction according to aforementioned factors should be precisely identified. In this study, unconfined uniaxial compressive test for two types of closed-cell structure polyurethane foam, namely, 0.16 and $0.32g/cm^3$ of densities were carried out. In addition, the void volume fraction of three different domains, namely, center, surface and buckling regions under various compressive strains (10 %, 30 %, 50 % and 70 %) were quantitatively observed using Micro 3D Computed Tomography(micro-CT) scanning system. Based on the experimental results, the relationship between compressive strain and void volume fraction with respect to cell size, density and boundary condition were investigated.