• 한국생물공학회:학술대회논문집
• /
• 2005.10a
• /
• pp.287-292
• /
• 2005

The crude polysaccharides(C-CPF, C-CPM, C-CPB) derived from fruiting body, mycelia and mycelia free broth of cordyceps militaris were obtained by ethanol precipitation of hot water extracts. After a batch fermentation of C. militaris was carried out in a 5 L jar vessel, endo-polysaccharide and exo-polysaccharide were obtained. They were demonstrated as the hetero polysaccharides which were composed of glucsose, galactose and mannose by performed with HPAEC(high pH anion exchange chromatography) and conformation of random coil by its complex forming ability with congo red reagent. They were purified by ion exchange (DEAE-cellulose) and gel filtration chromatography. They were monitered by phenol-sulfuric acid method and Bradford method. The NO induction activities of crude polysaccharides and purified polysaccharides derived from mycelia free broth were enhanced rather than LPS(lipo polysaccharide) which was used as a general NO inducer. These effects presumably contibute to the antitumor activities. The homogenieties and molecular weights of polysaccharides were determined by using Sepharose CL-6B. The yield, molecular weights and NO induction activities of C-CPFN Fr.III, C-CPMN Fr.III, C-CPBN Fr.II were 0.387, 0.408 and 0.153, 127 K 210 K and 36 K, 40.79%, 88.72%, and 104.17%, respectively.

• Journal of Korean Society on Water Environment
• /
• v.30 no.5
• /
• pp.517-523
• /
• 2014

In order to remove both nitrate and sulfate present in the concentrate of RO(reverse osmosis) process, a combined bio-regeneration and ion-exchange(IX) system was studied. For this purpose, both denitrifying bacteria(DNB) and sulfate reducing bacteria(SRB) were simultaneously cultivated in a bio-reactor under anaerobic conditions. When the IX column containing a nitrate-selective A520E resin was fully exhausted by nitrate and sulfate, the IX column was bio-regenerated by pumping the supernatant of the bio-reactor, which contains MLSS concentration of $125{\pm}25mg/L$, at the flowrate of 360 BV/hr. Even though the nitrate-selective A520E resin was used, the breakthrough curves of ionic species showed that sulfate was exhausted earlier than nitrate. The reason for this result is due to the fact that the concentration of sulfate in RO concentrate was 36 to 48 times higher than nitrate. The bio-reactor was successfully operated at a volumetric loading rate of 0.6 g $COD/l{\cdot}d$, nitrate-N loading rate of 0.13 g $NO_3{^-}-N/l{\cdot}d$, and sulfate loading rate of 0.08 g $SO_4{^{2-}}/l{\cdot}d$. The removal rate of SCOD, nitrate-N, sulfate was 90, 100, and 85%, respectively. When the virgin resin was fully exhausted and consecutively bio-regenerated for 2 days, 81% of nitrate and 93% of sulfate were reduced. When the virgin resin was repeatedly used up to 4 cycles of service and bio-regeneration, the ion-exchange capacity of bio-regenerated resin decreased to 95, 91, 88, and 81% of virgin resin.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.22 no.4
• /
• pp.284-292
• /
• 2012

Objectives: The objective of this study was to investigate the relations between the bacterial concentration and the environmental factors in the water soluble metal working fluids at factories. Methods: The bacterial concentrations for airborne and fluid samples of 7 factories were quantified during the summer season. And we statistically analysed the relations between the bacterial concentrations and the factors such as temperature, relative humidity, usage quantity, mixing ratio and exchange interval. Results: The geometric mean levels of the airborne bacterial concentrations were 79.1(range : N.D.~686) $CFU/m^{3}$ and 68.1(range: N.D.~919) $CFU/m^{3}$ in the process and outdoor. The airborne bacterial concentrations showed no statistical difference by process, usage quantity, mixing ratio and exchange interval. The airborne bacterial concentrations had negatively weak correlations with air temperature and relative air humidity(p<0.05). The bacterial concentrations and pH showed significantly negative correlations in the fluids(p<0.05). And the airborne bacterial concentrations in factories and those in metal working fluids showed no statistical relationship. Conclusions: In the water soluble metal working fluids using factories, the airborne bacterial concentrations of the process were related to those of the outdoor and environmental factors, rather than the onsite contaminated metal working fluids.

• Progress in Medical Physics
• /
• v.28 no.4
• /
• pp.135-143
• /
• 2017

Chemical Exchange Saturation Transfer (CEST) imaging is a method to detect solutes based on the chemical exchange of mobile protons with water. The solute protons exchange with three different patterns, which are fast, slow, and intermediate rates. The CEST contrast can be obtained from the exchangeable protons, which are hydroxyl protons, amine protons, and amide protons. The CEST MR imaging is useful to evaluate tumors, strokes, and other diseases. The purpose of this study is to review the mathematical model for CEST imaging and for measurement of the chemical exchange rate, and to measure the chemical exchange rate using a 3T MRI system on several amino acids. We reviewed the mathematical models for the proton exchange. Several physical models are proposed to demonstrate a two-pool, three-pool, and four-pool models. The CEST signals are also evaluated by taking account of the exchange rate, pH and the saturation efficiency. Although researchers have used most commonly in the calculation of CEST asymmetry, a quantitative analysis is also developed by using Lorentzian fitting. The chemical exchange rate was measured in the phantoms made of asparagine (Asn), glutamate (Glu), ${\gamma}-aminobutyric$ acid (GABA), glycine (Gly), and myoinositol (MI). The experiment was performed at a 3T human MRI system with three different acidity conditions (pH 5.6, 6.2, and 7.4) at a concentration of 50 mM. To identify the chemical exchange rate, the "lsqcurvefit" built-in function in MATLAB was used to fit the pseudo-first exchange rate model. The pseudo-first exchange rate of Asn and Gly was increased with decreasing acidity. In the case of GABA, the largest result was observed at pH 6.2. For Glu, the results at pH 5.6 and 6.2 did not show a significant difference, and the results at pH 7.4 were almost zero. For MI, there was no significant difference at pH 5.6 or 7.4, however, the results at pH 6.2 were smaller than at the other pH values. For the experiment at 3T, we were only able to apply 1 s as the maximum saturation duration due to the limitations of the MRI system. The measurement of the chemical exchange rate was limited in a clinical 3T MRI system because of a hardware limitation.

• Journal of the Korean Ceramic Society
• /
• v.24 no.4
• /
• pp.335-342
• /
• 1987

There were several numbers of studies on chemically strengthening glass. Most of them were strengthened in molten salt bath below transformation range of glass. Apart from them, this study used solution hydration technique by Autoclave. After determining proper concentration of AgNO3 salt solution, experimental condition varied from 4hrs to 16hrs at relatively low temperature (180, 200, 220$^{\circ}C$). The results showed that the Soda-Lime-Silica glass could be strengthened by diffusion mechanism without influence of water above 15% salt solution. Because of Ag+ ion penetration in glass surface, yellow color appeared and decreased transmittance at visible range. Modulus of rupture was increased with the amount of exchange and brittleness was decreased.

• Nuclear Engineering and Technology
• /
• v.45 no.1
• /
• pp.61-66
• /
• 2013

Among the radioactive wastes generated from the nuclear power plant, a radioactive nuclide such as $^{129}I$ is classified as a difficult-to-measure (DTM) nuclide, owing to its low specific activity. Therefore, the establishment of an analytical procedure, including a chemical separation for $^{129}I$ as a representative DTM, becomes essential. In this report, the adsorption and recovery rate were measured by adding $^{125}I$ as a radio-isotopic tracer ($t_{1/2}$ = 60.14 d) to the simulation sample, in order to measure the activity concentration of $^{129}I$ in a pressurized-water reactor primary coolant. The optimum condition for the maximum recovery yield of iodine on the anion exchange resins (AG1 x2, 50-100 mesh, $Cl^-$ form) was found to be at pH 7. In this report, the effect of the boron content in a pressurized-water reactor primary coolant on the separation process of $^{129}I$ was examined, as was the effect of $^3H$ on the measurement of the activity of iodine. As a result, no influence of the boron content and of the simultaneous $^3H$ presence was found with activity concentrations of $^3H$ lower than 50 Bq/mL, and with a boron concentration of less than 2,000 ${\mu}g/mL$.

• Membrane Journal
• /
• v.14 no.1
• /
• pp.44-52
• /
• 2004

This paper concerns the development of a cationic polymeric membranes for direct methanol fuel cell. The crosslinked poly(vinyl alcohol) (PVA) membranes with poly(acrylic acid-co-maleic acid) (PAM) and hydroquinonesulfonic acid (HQSA) as the crosslinking agents were prepared according to the amount of crosslinking agents. The resulting membranes were characterized in terms of methanol permeability, proton conductivity, water content and ion exchange capacity. The methanol permeability and proton conductivity increased with increasing PAM content up to 9 wt% and then decreased. This trend is considered the effect of the cross linking rather than the introduction of hydrophilic groups. When the HQSA contents were varied, no interesting increases of proton conductivity, water content and ion exchange capacity were found.

• Journal of Environmental Science International
• /
• v.13 no.1
• /
• pp.89-97
• /
• 2004

An author has been known that A-type zeolite supported with silver ions has excellent antibacterial activity. However, it is no research of concern in the antibacterial activity of eluted silver ions. This study tested the elution of silver ions from A-type zeolite silver ions in deionized distilled water and NaNO$_3$ aqueous solution. In NaNO$_3$ aqueous solution of 74mM to 588mM, it was found that the concentration of silver ions and electric conductivity increased with the increasing concentration of sodium ions, and equilibrated at 15 min, and the ion exchange equilibrium coefficient, k, is 1.3${\times}$10$\^$-3/. However, deionized distilled water is not equilibrated to pass 6 months. A-type zeolite sodium ions showed no antibacterial activity. It was found that antibacterial activity was exhibited even at the concentration of 10 nM of eluted silver ions, and E-coli died with the incorporation of 2.43${\times}$10$\^$8/ Ag ion/cell. antibacterial activity of A-type zeolite silver ions were mainly attributed to hydroxyl radical.

• Journal of environmental and Sanitary engineering
• /
• v.9 no.2
• /
• pp.41-49
• /
• 1994

Water- borne infectious diseases can be acquired by contact with contaminated water or by ingestion of contaminated water. There are many water- borne infectious agents such as bacteria, virus, and parasite. Among many of water- borne infectious diseases, health authorities of Korean government has particularly intensified to prevent and control typhoid fever(class I ), shigellosis(class I ), cholera(class I ), paratyphoid fever(class I), amebiasis(class II ) and leptospirosis(euivalent to class II ) under the communicable disease control law. Water- borne disease Prevention and control guideline itself has been also well provided by the health authorities. However, in practical public health point of view, there are still many problems remained to be solved out; no prospective investigation project to survey water borne infectious diseases under the national disease prevention and control programmes, incredible statistic data of annual notifiable disease report frequent appearance and varieties of drug resistance water- borne infectious agents, little cooperation and information- exchange system in between the related government authorities( the health authorities, the environment sanitation authorities and the food hygiene authorities) which should be closely collaborated, lack of health consciousness of the people, necessity of evaluation and Hndification on to the outcomes of performed health activities and programmes, neglect activities for water quality investigation, shortage of expertise and human resources in the related field, and poor investment of the government budget to develope and improve public health and sanitation field. In order to prevent and control water- borne infectious diseases effectively, it is emphasized that all the above indicated should be considered and performed to improve under the national health and sanitation development programmes.

• Journal of Applied Biological Chemistry
• /
• v.42 no.4
• /
• pp.166-168
• /
• 1999

Inulo-oligosaccharides (IOS, $F_n$, n=2-6) were purified from enzymatic hydrolysates of water-soluble extract of Jerusalem artichoke tubers. Quantification of inulo-oligosaccharides was done using high pH anion exchange chromatography with pulsed amperometric detector (HPAEC-PAD) at the concentration range of 10-100 mg/L, which was compared with that of fructo-oligosaccharides (FOS, $GF_n$, n=1-7). Peak areas per mg IOS were higher than FOS at the same degree of polymerization (DP). Specific peak areas of IOS increased proportionally as DP increased up to six, in contrast to FOS showing no linearity.