• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1476-1484
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• 2023

Laboratory experiments and point monitoring of reservoir sediments have proven that stable sulfate reduction (SSR) can lower the concentrations of toxic metals and sulfate in acidic groundwater for a long time. Here, we hypothesize that SSR occurred during in situ leaching after uranium mining, which can impact the fate of acid groundwater in an entire region. To test this, we applied a sulfur isotope fractionation method to analyze the mechanism for natural attenuation of contaminated groundwater produced by acid in situ leaching of uranium (Xinjiang, China). The results showed that δ³⁴S increased over time after the cessation of uranium mining, and natural attenuation caused considerable, area-scale immobilization of sulfur corresponding to retention levels of 5.3%-48.3% while simultaneously decreasing the concentration of uranium. Isotopic evidence for SSR in the area, together with evidence for changes of pollutant concentrations, suggest that area-scale SSR is most likely also important at other acid mining sites for uranium, where retention of acid groundwater may be strengthened through natural attenuation. To recapitulate, the sulfur isotope fractionation method constitutes a relatively accurate tool for quantification of spatiotemporal trends for groundwater during migration and transformation resulting from acid in situ leaching of uranium in northern China.

• 미생물학회지
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• 제10권4호
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• pp.175-190
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• 1972

This work was designed to illustrate physiological effects on the elimination of sulfur and its compounds in petroleum using sulfur-reducing bacteria. Deulfurizing bacteria were collected from sewage and soil at several areas in Soul and Ulsan, Korea. Seven supecies of sulfur-reducing microbes isolated were identified as : Pseudomonas marginata, Ps.effusa, Ps. putrefaciens, Ps.pseudcmcnelli, Ps. xanthochlora, Ps.bowlesiae, and Ps.aeruginosa. And some experiments were performed to define the growing characteristics of the Pseudomonads and the results obtained are as follows : 1) Shaking culture method was more effective for the growth of the cells than stagnant culture. 2) Beef peptone medium was better for the growth than other media. 3) Cuprous chloride of 50 ppm and cupper sulfate of 300 ppm treated, respectively, in the medium were effective for the growth. 4) Benzene of toluene of 5,000 ppm and petroleum ether of 50,000 ppm did not show remarkable inhibitory effects on the growth.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.128-136
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• 2007

It is well known that two representative methods satisfy EURO-IV regulation from EURO-III. The first method is to achieve the regulation through the reduction of NOx in an engine by utilizing relatively high EGR rate and the elimination of subsequently increased PM by DPF. However, it results in the deterioration of fuel economy due to relatively high EGR rate. The second is to use the high combustion strategy to reduce PM emission by high oxidation rate and trap the high NOx emissions with DeNOx catalysts such as Urea-SCR. While it has good fuel economy relative to the first method mentioned above, its infrastructure is demanded. In this paper, the number distribution of nano PM has been evaluated by Electrical Low Pressure Impactor(ELPI) and CPC in case of Urea-SCR system in second method. From the results, the particle number was increased slightly in proportion to the amount of urea injection on Fine Particle Region, whether AOC is used or not. Especially, in case of different urea injection pressure, the trends of increasing was distinguished from low and high injection pressure. As low injection pressure, the particle number was increased largely in accordance with the amount of injected urea solution on Fine Particle Region. But Nano Particle Region was not. The other side, in case of high pressure, increasing rate of particle number was larger than low pressure injection on Nano Particle Region. From the results, the reason of particle number increase due to urea injection is supposed that new products are composited from HCNO, sulfate, NH3 on urea decomposition process.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1542-1546
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• 2015

The purpose of this study was to investigate the potential of zeolite-supported sulfatereducing bacteria (SRB) in enhancing the removal of Cu²⁺, Ni²⁺, and Cr⁶⁺ in contaminated seawater. Our results show that SRB-immobilized zeolite carriers can enhance the removal of heavy metals. In addition, heavy metals were generally better removed at conditions of 37°C. Cu²⁺, Ni²⁺, and Cr⁶⁺ were effectively removed by 98.2%, 90.1%, and 99.8% at 100 parts per million concentration of the heavy metals, respectively. These results indicate that SRB-zeolite carriers hold great potential for use in the removal of cationic heavy metal species from marine environment.

• Biomolecules & Therapeutics
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• 제1권1호
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• pp.50-57
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• 1993

This study characterized the effect of liver injury produced by hepatotoxicants on the biliary and urinary excretion of acetaminophen(AA) metabolites. Liver damage was produced in male S.-D. rats, 24 hr after dosing with carbon tetrachloride(4CCl_4,$ 0.75 mι/kg, ip) or thioacetamide(TA, 200 mg/kg, ip), or 16 hr after administration of cadmium chloride(4CdCl_2,$ 3.9 mg/kg, iv). Liver damage without renal injury was confirmed by measuring serum enzymes, creatinine and BUN levels as well as by histopathological examination. AA and its metabolites were measured for 3 hr by HPLC in rats injected iv with 1 mmo1/kg of AA. The excreted amounts of AA-glucuronide into bile were reduced to 60~70% of control rats by hepatotoxicants, but did not change urinary excretion of AA-glucuronide and AA-sulfate. Treatments with $CCl_4,\; CdCl_2$ and TA decreased the total (biliary plus urinary) excretion of thioethers of AA(30~50% of control), suggesting that these toxicants decrease cytochrome P-450-mediated toxification of AA. However, treatments of $CdCl_2$and TA markedly enhanced the excretion of AA-mercapturate into urine. Thus, 4CdCl_2$ and TA not only influence the formation of AA-glutathione, but may also alter the excretory routes (i.e. bile and urine) for the elimination of AA-metabolite.

• BMB Reports
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• 제31권1호
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• pp.31-36
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• 1998

Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), the first enzyme in the phenylpropanoid biosynthesis, catalyzes the elimination reaction of ammonium ion from L-phenylalanine. PAL was purified from the cytosolic fraction of Chinese cabbage (Brassica campestris ssp. napus var. pekinensis) through ammonium sulfate fractionation, DEAE-cellulose chromatography, Sephadex G-200 chromatography, and Q-Sepharose chromatography. It consists of four identical subunits, the molecular mass of which was estimated to be about 38,000 daltons on SDS-PAGE. The optimal pH and temperature of the purified enzyme are 8~9 and $45^{\circ}C$, respectively. Its activity is greatly inhibited by $Zn^{2+}$ ion, and strongly activated by caffeic acid. The purified PAL has some different characteristics compared to those obtained with other PALs.

• Applied Biological Chemistry
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• 제37권4호
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• pp.221-225
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• 1994

농산폐섬유소 자원을 이용하여 세균 단세포단백질(single cell protein)을 생산하기 위한 연구로서 부엽토에서 분리된 Cellulomonas sp. KL-6의 증식에 미치는 열처리 및 항생물질의 효과에 대해 조사하였다. KL-6 균주는 $65^{\circ}C$에서 5분, $75^{\circ}C$에서 1분 및 $85^{\circ}C$에서 15초까지 열처리시에는 증식하였고 그 이상의 온도에서는 처리시간에 관계없이 자라지 못하였다. $48^{\circ}C$에서 10분간의 예비 열처리는 본 균주의 열저항성을 증가시키지 못하였다. 기질 중 casamino acid(1%), yeast extract(1%), xylose(5%)는 KL-6 균주의 열저항성을 증가시켰으나 cysteine(0.03 M), sodium citrate(1%), casein(1%)은 반대로 열저항성을 감소시켰다. KL-6 균주는 $penicillin-G(1.536\;{\mu}g/ml)$와 $ampicillin(3.125\;{\mu}g/ml)$에 감수성인 반면, kanamycin에 대해서는 $200\;{\mu}g/ml$ 이상에서도 강한 내성을 보였다. SDS 처리에 의해 kanamycin의 내성이 제거되었고 제거율은 $9.2{\sim}31.2%$로 각각 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1498-1504
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• 2005

Competitive direct ELISA was developed to detect gentamicin residues. Mice immunized with gentamicin-keyhole limpet hemocyanin (KLH) conjugate developed good antiserum titers, which gradually increased with booster injections, indicating immunization was successfully processed. Monoclonal antibody against gentamicin was prepared using hybridoma cells cloned by limit dilution of fused cells. IgG was purified from ascites fluid of hybridoma cell-injected mice through ammonium sulfate precipitation and Sephadex G-25 gel filtration. After the gel filtration, fractions of high antibody titer were further purified through affinity chromatography on protein A/G column. Monoclonal antibody against gentamicin was confirmed as IgG1, which has kappa light chain. Cross-reactivities ($CR_{50}$) of gentamicin monoclonal antibody to other aminoglycosides (kanamycin, neomycin, and streptomycin) were less than 0.005%, indicating the monoclonal antibody was highly specific for gentamicin. Standard curve constructed through competitive direct ELISA showed measurement range (from 80 to 20% of B/$B_0$ ratio) of gentamicin was between 1 and 40 ng/ml, and 50% of B/$B_0$ ratio was about 4 ng/ml. The gentamicin concentration rapidly increased to 1,300 ng/ml after the intramuscular administration up to 2 h, then sharply decreased to less than 300 ng/ml after 4 h of withdrawal, during which the elimination half-life ($t_{1/2}$) of gentamicin in the rabbit plasma was estimated to be 1.8 h. Competitive direct ELISA method developed in this study using the prepared monoclonal antibody is highly sensitive for gentamicin, and could be useful for detecting gentamicin residues in plasma of live animals.

• 한국환경과학회지
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• 제25권3호
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• pp.425-438
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• 2016

This study carried out zeta potential measurements of the Microcystis sp. under various solutions condition and investigated the characteristics of Microcystis sp. through the size control of microbubbles to eliminate algae that causes problems in aquatic ecosystems and human activities. DAF process was adopted and several coagulants were used to remove the Microcystis sp. CCD Camera was used to measure and analyze the size of microbubble, and fluorescent microscope was used to observe the particle, algae species and community. Zeta potential behavior of the algae was analyzed by using ELS-Z. Lab-scale and pilot-scale experiments were conducted to test flotation process. Polyaluminium chloride(PAC) coagulant was used, and the removal efficiency of the algae was assessed through Chlorophyll-a analysis. In the Lab-scale experiment, 2.2 ppm, 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride was injected to coagulate the algae. The coagulated algae was floated by the microbubble. The microbubbles in the experiments were generated at a air pressure of 450 ~ 550 kPa. The microbubble size was controlled in $36{\mu}m$, $100{\mu}m$, and $200{\mu}m$, respectively by using different diffuser. The results of lab-scale experiments on flotation plant indicated that the average removal rate was about 90% or above for 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride. On the other hand, in the pilot-scale experiment, the removal efficiency was in the range of 85% to 95% in all dose ranges of polyalumium chloride and aluminium sulfate coagulants.

• 대한수의학회지
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• 제51권4호
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• pp.253-257
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• 2011

Amikacin is a semisynthetic derivative of kanamycin and primarily active against aerobic Gram-negative-pathogens with limited activity against Gram-positive bacteria. Meager study was reported on pharmacokinetic data on multi-days administration of amikacin. Hence, pharmacokinetics study was done in five clinically healthy goats (n = 5), after intravenous bolus injection of amikacin sulfate at the dose rate of 10 mg/kg body weight daily for three consecutive days. The amikacin concentrations in plasma and pharmacokinetics-parameters were analyzed by using microbiological assay technique and noncompartmental open-model, respectively. The mean peak plasma concentrations (Mean ${\pm}$ SD) of amikacin at time zero ($Cp^{0}$) was $114.19{\pm}20.78$ and $128.67{\pm}14.37{\mu}g/mL$, on day 1st and 3rd, respectively. The mean elimination half-life ($t_{1/2}ke$) was $1.00{\pm}0.28h$ on day 1st and $1.22{\pm}0.29h$ on day 3rd. Mean of area under concentration-time curve ($AUC_{0{\rightarrow}{\infty}}$) was $158.26{\pm}60.10$ and $159.70{\pm}22.74{\mu}g.h/mL$, on day 1st and 3rd respectively. The total body clearance ($Cl_{B}$) and volume of distribution at steady state (Vdss) on day 1st and 3rd were $Cl_{B}=0.07{\pm}0.02$ and $0.06{\pm}0.01L/h.kg$ and $Vdss=0.10{\pm}0.03$ and $0.11{\pm}0.05L/kg$, respectively. No-significant difference was noted in both drug-plasma concentration and pharmacokinetics-parameters, respectively. Amikacin concentration in plasma was found higher up-to 4 h and 6 h onward on down-ward trends favour to reduce toxicity. Which also support the pharmacokinetic-pharmacodynamic way of dosing of aminoglycosides and hence, amikacin may be administered 10 mg/kg intravenously daily to treat principally Gram-negative pathogens and limitedly Gram-positive-pathogens.