• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4246-4251
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• 2023

The optimized design of a Neutron Activation Analysis (NAA) system, including Delayed Gamma NAA (DGNAA) and Prompt Gamma NAA (PGNAA), has been proposed in this research based on Mevex Linac with 5 MeV electron energy and 50 kW power as a neutron source. Based on the MCNPX 2.6 simulation, the optimized configuration contains; tungsten as an electron-photon converter, BeO as a photoneutron target, BeD₂ and plexiglass as moderators, and graphite as a reflector and collimator, as well as lead as a gamma shield. The obtained thermal neutron flux at the beam port is equal to 2.06 × 10⁹ (# /cm².s). In addition, using the optimized neutron beam, the detection limit has been calculated for some elements such as H-1, B-10, Na-23, Al-27, and Ti-48. The HPGe Coaxial detector has been used to measure gamma rays emitted by nuclides in the sample. By the results, the proposed system can be an appropriate solution to measure the concentration and toxicity of elements in different samples such as food, soil, and plant samples.

• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1182-1189
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• 2004

Cytosine deaminase (cytosine aminohydrolase, EC 3.5.4.1) stoichiometrically catalyzes the hydrolytic deamination of cytosine and 5-fluorocytosine to uracil and 5-fluorouracil, respectively. The intracellular cytosine deaminase from Chromobacterium violaceum YK 391 was purified to apparent homogeneity with 272.9-fold purification with an overall yield of $13.8\%$. The enzyme consisted of dimeric polypeptides of 63 kDa, and the total molecular mass was calculated to be approximately 126 kDa. Besides cytosine, the enzyme deaminated 5-fluorocytosine, cytidine, 6-azacytosine, and 5-methylcytosine, but not 5-azacytosine. Optimum pH and temperature for the enzyme reaction were 7.5 and $30^{\circ}C$, respectively. The enzyme was stable at pH 6.0 to 8.0, and at 30T for a week. About $70\%$ of the enzyme activity was retained at $60^{\circ}C$ for 5 min. The apparent $K_{m}$ values for cytosine, 5-fluorocytosine, and 5-methylcytosine were calculated to be 0.38 mM, 0.87 mM, and 2.32 mM, respectively. The enzyme activity was strongly inhibited by 1 mM $Hg^{2+},\;Zn^{2+},\;Cu^{2+},\;Pb^{2+},\;and\;Fe^{3+}$, and by o-phenanthroline, $\alpha,\;{\alpha}'$-dipyridyl, p-choromercuribenzoate, N-bromosuccinimide, and cWoramine­T. In addition, the enzyme activity was strongly inhibited by I mM 2-thiouracil, and weakly inhibited by 2-thiocytosine, or 5-azacytosine. Finally, intracellular and extracellular cytosine deaminases from Chromobacterium violaceum YK 391 were found to have a different optimum temperature, apparent $K_{m}$ value, and molecular mass.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1605-1610
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• 2012

Gelam and Nenas monofloral honeys were investigated in this study for their chemopreventive effects against HT 29 colon cancer cells. MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolim) assays showed more effective inhibition of colon cancer cells proliferation by Gelam honey with $IC_{50}$ values of 39.0 mg/ml and 85.5 mg/ml respectively after 24 hours of treatment. Alkali comet assays revealed both honeys increased DNA damage significantly in a dose dependent manner. In addition, annexin V-FITC/PI flow cytometry demonstrated that at $IC_{50}$ concentrations and above, both Gelam and Nenas honeys induced apoptosis significantlyat values higher than for necrosis (p<0.05). Measurement of prostaglandin $E_2$ ($PGE_2$) confirmed that Gelam and Nenas honeys reduced its production in $H_2O_2$ inflammation-induced colon cancer cells. In conclusion, our study indicated and confirmed that both Gelam and Nenas honeys are capable of suppressing the growth of HT 29 colon cancer cells by inducing apoptosis and suppressing inflammation.

• Journal of Life Science
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• v.18 no.11
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• pp.1485-1492
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• 2008

Prostaglandin $A_2$ ($PGA_2$), one of cyclopentenone PGs, induced both apoptosis and heme oxygenase (HO)-1 expression in U2OS cells. $PGA_2$-induced apoptosis was not perturbed by either over-expression or knock-down of HO-1, whereas $H_2O_2$-induced cell death was inversely modulated by the expression level of HO-1. In addition, N-acetyl-L-cysteine (NAC), a thiol antioxidant, blocked both apoptosis and HO-1 expression induced by $PGA_2$. But, non-thiol antioxidants like butylated hydorxyanisole (BHA) and ascorbic acid did not block either apoptosis or HO-1-induction. Taken together, these results suggest that $PGA_2$ induces both apoptosis and HO-1 expression, which are critically related to the thiol- reactivity of $PGA_2$, but not oxidative stress, and HO-1 expression may be independent or functionally located downstream of apoptosis by $PGA_2$ without contribution to apoptosis progression.

• Journal of the Korean Ceramic Society
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• v.41 no.10 s.269
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• pp.749-755
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• 2004

Fluosilicic acid ($H_2SiF_6$) is recovered as aqueous solution which absorbs $SiF_4$ produced from the manufacturing of industrial-graded $H_3PO_4$ or HF. Generally, fluosilicate salts prepared by the reaction between $H_2SiF_6$ and metal salts. Addition of fluosilicate salts to cement endows odd properties through unique chemical reaction with the fresh and hardened cement. In this study, two-component fluosilicate salt based chemical admixtures (MZ) of $4\%,\;6\%$, and $8\%$ concentration were prepared by the reaction of $H_2SiF_6$ ($25\pm2\%$) and metal salts. The effect of concentration of MZ at a constant adding ratio on the hydration and watertightness of cement were investigated respectively. In a cement containing MZ, metal fluorides such as $CaF_2$ and soluble silica by hydrolysis were newly formed during hydration. The total porosity of the hardened cement was lower in the presence of U because of packing role of metal fluoride and pozzolanic reaction of soluble $SiO_2$. Consequently, the watertightness of the hardened paste containing MZ was more improved than non-added (plain) due to an odd hydration between cement and MZ.

• Journal of the Korea Institute of Building Construction
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• v.10 no.4
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• pp.41-47
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• 2010

It has been continuously noted that many sewage treatment concrete structures have deteriorated due to sulfur-oxidizing bacteria. There have been many reports on approaches to protecting concrete from this bacteria corrosion. The purpose of this study is to evaluate the inhibition of growth of a sulfur-oxidizing bacterium by a antifungal agent such as $NiSO_4{\cdot}6H_2O$, and the characteristics of polymer cement mortar using nickel type antifungal agent. First, we developed antifungal agents using metal nickel and $NiSO_4{\cdot}6H_2O$ to inhibit the growth of thiobacillus novellus, which is the sulfur-oxidizing bacteria in concrete. Then, ordinary cement mortar and polymer cement mortar using nickel type antifungal agent with various polymer-cement ratios, and antifungal agent content were prepared, and were tested for the antifungal adding effect, compressive and flexural strengths, expansion and leaching of nickel ion. From the test results, it was confirmed that the adding of an antifungal agent has an inhibition effect on the growth of sulfur-oxidizing bacteria at antifungal agent contents of 20 mM or more. In addition, the strengths and expansion of polymer cement mortars are not significantly changed by the addition of an antifungal agent. Therefore, the nickel-type antifungal agent developed in this study can be used to improve the durability of reinforced concrete hume pipe in the construction industry.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.881-885
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• 2005

Purpose : Airway dehydration and subsequent hyperosmolarity of periciliary fluid are considered critical events in exercise-induced bronchoconstriction. The aim of this study was to establish if a hyperosmolar challenge could induce activation of eosinophils. Methods : Human eosinophilic leukaemic cell lines, EoL-1 cells were incubated with hyperosmolar solutions for 15 minutes. Activation of EoL-1 cells was monitored by degranulation and superoxide anion production. In addition, we examined surface expression of CD69 and ICAM-1. Results : Hyperosmolar stimuli didn't induce superoxide anion production and degranulation. In addition, EoL-1 cells cultured with hyperosmolar medium at 930 mOsm/kg $H_2O$ resulted in no significant increment in fluorescent intensity of CD69 and ICAM-1 expression compared with results for cells incubated with isomolar medium. Conclusion : We found that hyperosmolar stimuli don't cause activation of EoL-1 cells, but further studies are required to determine the role of eosinophil in the mechanism of exercise-induced asthma.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.280-287
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• 2000

Three antimicrobial compounds (SL-l, SL-2 and SL-3) were isolated and identified from the marine red alga, Symphyocladia latiuscula. In addition, their biological functionalities such as cytotoxicity and desmutagenic activity were investigated. From the cryophyllized S. JatiuscuJa, SL-l, SL-2 and SL-3 were purified by solvent extractions and HPLC.SL-2 was crystallized in benzene-diethyl ether solvent. On the EI-MS spectra, it was found that they had three bromines in their structure which showed typical signal strength ratios at $M^+, [M+2]^+, [M+4]^+, [M+6]^+ (13: 38: 37: 12)$. $SL-l$ was identified as 2,3,6-tribromo-4,5-dihydroxybenzyl alcohol ($C_8H_7Br_3O_3, MW=374$) by NMR and MS spectra. SL-2 was assigned as 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether ($C_8H_7Br_3O_3, MW=388$) and confirmed by X-ray crystallographic analysis. SL-3 was presumed as an isomer of SL-2. Methanol extract of the S. latiuscula showed antimicrobial activities against all strains tested (bacteria, 15 strains; yeasts, 17 strains; fungi, 4 strains), much or less. The strongest inhibition activity of the methanol extract was to the Vibrio mimicus ($50 {\mu}g/ml$) and V. vulnificus ($50 {\mu}g/ml$). The mice injected intraperitoneally with 3 mg of SL-l and 5 mg of 5L-2 showed no acute toxicity response. SL-2 showed higher desmutagenic activity than SL-l against PhIP and MeIQx.

• Journal of the Korean Ceramic Society
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• v.42 no.11 s.282
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• pp.722-728
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• 2005

A wet-chemical route was utilized to obtain nanosized crystalline goethite ($\alpha$-FeOOH) particle, which was known as an oxidation catalyst in reducing carbon monoxide (CO) and dioxine during incineration. A cost-effective $FeSO_4{\cdot}7H_2O$ was used as starting raw material and a successive process of hydrolysis-oxidation was utilized as synthetic method. The effects of the initial $Fe^{2+}$ concentration, hydrolysis time and oxidation period on the crystalline phase and particle characteristics were systematically investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and BET analyses. It was found that the spindle-shaped crystalline $\alpha$-FeOOH particle with the width of 70 nm and the length of 200 nm could be obtained successfully when the initial concentration of 1.5 M, hydrolysis time of 4h, and oxidation period of 10 h, respectively. In addition, it was observed that the spindle-shaped $\alpha$-FeOOH particle consisted of nano-sized primary crystallites of $30\~50\;nm$, which were de-agglomerated into individual particle and successively re­agglomerated into spherical or irregular-shaped agglomerates beyond certain periods in the hydrolysis and oxidation process.

• Korean Journal of Poultry Science
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• v.29 no.4
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• pp.265-270
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• 2002

This study was conducted to determine the effect of aluminum sulfate[Al$_2$(S0$_4$)$_3$$.$14H$_2$O], commonly referred to as ALUM, addition to broiler litter on 3 and 6 week old broiler performance and the nitrogen content of the litter at 6 weeks of age. The two treatment groups were 134 identical diets with the same protein levels, but one group(T$_1$) had ALUM added as a top dressing to the litter at a rate of 200 g ALUM / kg of rice bran, while T$_2$ did not have ALUM added to the litter. Feed consumption for T$_1$ was higher in the 22 to 42 day-old and 0 to 42 day-old periods (P<0.05). Body weight in T$_1$ was also higher in the 0 to 42 day -old period (P<0.0l). There was no difference, however, in the feed : gain ratio between T$_1$ and T$_2$ During the first 5 weeks, T$_1$ had significantly less(P<0.05 or 0.01) ammonia emission from the litter than T$_2$ but at 6 weeks there was no difference in ammonia concentration between the two groups. At 6 weeks, T$_1$ had a lower litter pH than Ta (P<0.05) and total Kjeldahl nitrogen(TKN) was higher far T$_1$ than T$_2$ (P<0.05). However,71 did not show any difference from T$_2$ in the content of NH4-N and NO3-N. In summary, the addition of ALUM to broiler litter improved broiler performance at 6 weeks, while increasing nitrogen content from the litter used as the nitrogen fertilizer although ammonia emission was increased in T$_1$ at 6 weeks.