• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.309-315
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• 2000

The changes of Np oxidation state in nitric acid and the effect of nitrous acid on the oxidation state were analyzed by spectrophotometry, solvent extraction, and electrochemical methods. An enhancement of Np extraction to 30 vol.% TBP was carried out through adjustment of Np oxidation state by using a glassy carbon fiber column electrode system. The information of electrolytic behavior of nitric acid was important because the nitrous acid affecting the Np redox reaction was generated during the electrolytic adjustment of the Np oxidation state. The Np solution used in this work consisted of Np（V) and Np（Ⅵ）without （IV）. The composition of Np（V) in the range of 0.5M -5.5 M nitric acid was 32% ~ 19%. The electrolytic oxidation of Np（V) to Np（Ⅵ）in the solution enhanced Np extraction efficiency about five times higher than the case without the electrolytic oxidation. It was confirmed that the nitrous acid of less than about 10-5 M acted as a catalyst to accelerate the chemical oxidation reaction of Np（V) to Np（Ⅵ）.

• Toxicological Research
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• v.24 no.4
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• pp.297-305
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• 2008

This study was carried out to measure the concentration of heavy metals (Pb, Mn, Cr, Cd, Ni, Zn, and Cu) in water and Bolti fish (Tilapia nilotica) samples collected from Rasheed branch of River Nile, north of El-Giza Governorate, Egypt by atomic absorption spectrophotometry. The investigated districts through which the branch passes include El-Manashi, Gezzaya, El Katta, Abo Ghaleb and Wardan. Based on WHO and FAO safety reference standards, the results of the current study showed that water and fish tissues were found to contain heavy metals at significantly variable concentration levels among the investigated districts. They were polluted with respect to all the metals tested at Gezzaya district. However, the levels of analyzed metals in water and fish tissues were found lower than legal limits in other districts. The heavy metals showed differential bioaccumulation in fish tissues of the different districts as the accumulation pattern (as total heavy metal residues) was district dependant as follow: Gezzaya > Wardan > El Katta > Abo Ghaleb > El Manashi.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.571-576
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• 2011

Activity carbon (AC), Cu and $Cu_2O$ modified $TiO_2$ composites (Cu/$Cu_2O$-AC/$TiO_2$) were prepared using a sol-gel method. The characteristics of the composites were evaluated using Brunauer-Emmett-Teller (BET) surface area measurements, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis and scanning electron microscope (SEM) analysis. A methyl orange (MO) solution under visible light irradiation was used to determine the photocatalytic activity. The degradation of MO was determined using UV/Vis spectrophotometry. $Cu_2O$, Cu and the cooperative effect of the AC increased the photo-absorption effect, thus increasing in photocatalytic activity.

• Journal of Environmental Health Sciences
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• v.14 no.2
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• pp.51-64
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• 1988

It has been suggested that calcium is only one of many metals that compete with toxic metals in the body. Therefore, this study was carried out to determine the influence of water hardness on accumulation of heavy metals in rats. The seventy-five rats were divided into control and case groups. Case group was subdivided into four subgroups in proportion to the concentration of water hardness respectively, such as, 0, 250, 500, 1000ppm. Control group was fed on only deionized water, but case groups were fed on hard water with ionized heavy metals (Cd 150mg + Pb 300mg + Cu 300mg/l) for 20, 40, 60 days. The concentrations of cadmium, lead and copper were measured by atomic absorption spectrophotometry (Perkin Elmer 2380) in livers and kidneys. The results of the study are summarized as following 1. The concentration of cadmium accumulation showed the tendency of decrease in proportion to water hardness in both livers and kidneys of rats having been fed for only 60 days, respectively. 2. In only livers of rats having been fed for 60 days, essential metal, copper had the tendency of decrease according as hardness in water. 3. It was impossible to compare case with control about the tendency of lead accumulation because there was no difference between the two in livers and kidneys respectively.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.123-131
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• 2015

During several visits to the Cebu City landfill in the Philippines, plants were observed growing within the area, including on top of the garbage piles. Studying the response of these plants is important in assessing which can be used in remediating metal contaminated soils. This study aimed to determine whether the plants in the Cebu City landfill excluded or accumulated cadmium (Cd) and chromium (Cr) in the plant tissues. The floristic composition of the landfill was analyzed prior to the sample collection. The samples were acid-digested before the desired elements were measured using atomic absorption spectrophotometry (AAS). The Cd and Cr concentrations in the plant root-zone soil were also measured using AAS. The results indicated that the landfill substrate was generally acidic based on the results of the pH measurement. Of the 32 plant species sampled, Cyperus odoratus showed potential for Cd uptake and internal transfer; Cenchrus echinatus, Vernonia cinerea and Terminalia catappa for Cr uptake, and Cynodon dactylon for Cr internal transfer. The plants in the landfill differed in their response towards the heavy metals. To confirm the behavior of C. odoratus towards Cd, and C. echinatus, C. dactylon, V. cinerea, and T. catappa towards Cr, controlled experiments are recommended, as the plant samples analyzed were collected from the field.

• BMB Reports
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• v.37 no.5
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• pp.629-633
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• 2004

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450, and catalyzes the one-electron reduction of many drugs and foreign compounds. Various forms of spectrophotometric titration have been performed to investigate the electron-accepting properties of CPR, particularly, to examine its ability to reduce cytochrome c and ferricyanide. In this study, the reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH) by CPR was assessed as a means of monitoring CPR activity. The principle advantage of DPPH is that its reduction can be assayed directly in the reaction medium by a continuous spectrophotometry. Thus, electrons released from NADPH by CPR were transferred to DPPH, and DPPH reduction was then followed spectrophotometrically by measuring $A_{520}$ reduction. Optimal assay concentrations of DPPH, CPR, potassium phosphate buffer, and NADPH were first established. DPPH reduction activity was found to depend upon the strength of the buffer used, which was optimal at 100 mM potassium phosphate and pH 7.6. The extinction coefficient of DPPH was $4.09\;mM^{-1}\;cm^{-1}$. DPPH reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;28\;{\mu}M$, $K_{cat}\;=\;1690\;min^{-1}$). This method uses readily available materials, and has the additional advantages of being rapid and inexpensive.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.603-608
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• 1997

To improve animal production, a simple and accurate pregnancy diagnosis plays a very important role. Therefore, the purpose of this study was to develop an on-farm blood progesterone enzyme immunoassay (EIA) system for monitoring the early pregnancy in sows. Star tubes coated with mouse monoclonal anti-progesterone antibody were used for this proposed EIA system which was tested in field trials. The results could be obtained within 30 minutes either by spectrophotometry or the naked eye. Heparinized fresh blood samples collected from the ear vein of sows 17-22 days after breeding (day 0) were tested qualitatively to diagnose sows as pregnant or non-pregnant with high ( > 3 ng/ml) or low ($${{\leq_-}}3ng/ml$$) progesterone in the blood. To provided a double check data, plasma progesterone levels were also measured quantitatively by the same EIA system with some modification. Total agreement of diagnosis by the on-farm EIA kit and by farrowing or abortion from 128 tested sows was found to be 92.2% accuracy (93.1% on pregnant diagnosis and 83.3% on non-pregnant diagnosis). It was concluded that the on-farm EIA blood progesterone test is a very useful method for monitoring the early pregnancy status of sows.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.4
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• pp.358-366
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• 2012

A novel neuropeptide was isolated from the skin of the conger eel Conger myriaster using hagfish Eptatretus burgeri intestine as a bioassay system. The sequence of the purified peptide was analyzed using automated amino acid sequencing and MALDI-TOF mass spectrophotometry. The molecular ion peak in the MALDI-TOF mass spectrum of the peptide was at m/z 962.89 $(M+H)^+$. The sequence of the peptide was determined to be L-P-M-L-E-T-Q-M, and was tentatively named comyrin. To investigate the complete primary structure of comyrin, comyrin-OH and comyrin-$NH_2$ were synthesized and the chemical and pharmacological properties of the synthetic peptides were compared with those of the native peptide. However, the elution time of synthetic peptides did not match that of the native peptide on the reverse-phase HPLC chromatogram. In addition, the synthetic peptides did not cause contractile activity in the intestinal smooth muscle of the hagfish. Based on these results, one possible reason for this disagreement may be the presence of a D-amino acid in comyrin.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.297-304
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• 2013

Free-radical copolymerization of glycidyl methacrylate(GMA) and N-phthalimidoethyl acrylate(NPEA) were carried out at $60^{\circ}C$ in dimethylformamide(DMF) solution in the presence of benzoylperoxide(BPO) at low conversion. The polymers were characterized by IR and $^1H$-NMR. The compositions of the copolymer was analyzed by ultra violet(UV/Vis) spectrophotometry. The reactivity ratios of the monomer was determined by the application of Fineman-Ross(FR) and Kelen-T$\ddot{u}$d$\ddot{o}$s(KT) methods. The monomer reactivity ratios of the system and Alfrey-Price's resonance effect(Q) and polar effect(e) value for NIEA were determined as follow. The reactivity ratios of the monomer obtained from FR and KT are found to be $r_1$=0.87, $r_2$=0.98 and $r_1$=0.88, $r_2$=0.99 respectively. The Q and e values of poly(GMA-co-NPEM) calculated from $r_1$ and $r_2$ was Q= 1.31, e=0.75 respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.1
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• pp.35.2-72
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• 1990

N-Nitrosamines have been known to be strong carcinogens and are formed by the reaction of nitrous acid with amines. In this experiment the changes in the contents of nitrate nitrite trimethylaminoxide(TMAO) trimethylamine(TMA) and dimethylamine(DMA) during femen-tation of damsel fish were analyzed periodically and N-nitrosamines in a commercial products. N-Nitrosamines were determined by mineral oil distillation methods using gas chromatography-thermal energy anlyzer(GC-TEA) in a commerical product. Nitrate nitrite and amines were quantitate by colorimetric methods. Level of nitrate-N were gradually decreased but nitrite-n was not detected or trace. Contents of dimethlamine(DMA) and trimethlamine were mar-kedly increased while trimethylaminoxide nitrogen was decreased during the fermentation of damsel fish. The change of pH was in the ranges of 5,5-7.0 during fermentation of salted damsel fish. It was out of the optimum pH(3.0-3.4) for the formation of nitrosamine. N-Nitrosamines were not detected in salt-fermented damsel fist but much N-nitrosodimethyla-mine(NDMA) could be detected in salt-fermented damsel fish after adding 0.05M NaNo2 in the acidic condition. The identifaction of NDMA in it was confirmed by mass spectrophotometry. Nitrate decrea-sed during the fermentation of damsel fish. however nitrite was trace level and nitrosamines were not formed in its. This could be supposed that it was due to the rapid consumption of nitrite by amino acid and bacteria.