• Journal of the Korean Chemical Society
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• v.38 no.10
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• pp.705-709
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• 1994

The kinetics of the oxidation reaction of malonic acid by ceric ion in 1 M sulfuric acid solution at $20^{\circ}C$ have been investigated by spectrophotometric method. The reaction rate at a large excess of malonic acid was found to be pseudo-first order. The observed pseudo-first order rate constants, $k_{obs}$, are dependent on the concentration of malonic acid, [MA], of which relationship has been found to be $k_{obs}$ = (0.592[MA])/(1+14.5[MA]$^2$). A mechanism for the reaction has been suggested on the basis of the above rate equation. The rate determining step may be the electron transfer reaction between enolate type malonate anion, which is formed by the acid dissociation reaction of malonic acid, and Ce(IV). The rate depression in the range of high concentration of MA has been explained by the formation of 1 : 2 chelate between Ce(IV) and malonate. According to the mechanism, the pH dependence of the rate, which was studied by Sengupta et al., has also been explained.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.243-248
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• 2000

Oganic electroluminescent devices (OELD) with multilayer structures have been studied actively for the application to a flat-panel display. Netal-chelate complexes hrboxylate. These complexes were characterized by FT-IR, MS/FAB, $^1$H-NMR, UV-vis and photoluminescence (PL). More importantly, the electrochemical gap (Eg), electron affinity(EA) and ionization potential (IP) of these complex films were investigated. Data from cyclic voltammetry(CV) were compared with the bandgap obtained from UV-vis and discussed. Further studies on the EL of these new materials are now in progress.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.12
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• pp.1725-1728
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• 2004

An experiment was conducted to investigate the efficiency of transfer of dietary iron sources to eggs of laying hens. Eighty ISA-Brown laying birds of 30 wk old were housed in 40 cages of 2 birds each. Eight birds in four cages were assigned to one of the following ten treatments: T1; control, T2; 100 ppm iron supplementation with iron-methionine chelate (Fe-Met-100), T3; Fe-Met- 200, T4; Fe-Met-300, T5; 100 ppm iron supplementation with iron sulfate ($FeSO_4$-100), T6; $FeSO_4$-200, T7; $FeSO_4$-300, T8; 100 ppm iron supplementation with Availa-$Fe^{(R)}$ (Availa-Fe-100), T9; Availa-Fe-200 and T10; Availa-Fe-300. Results of 40 d feeding trial showed that there were no consistent responses in laying performance by source and level of iron supplementation. However, eggshell strength and color were improved by Fe supplementation. Egg iron content was maximized at 10-15 days after feeding supplemental Fe. Fe- Met was the most effective source in enriching Fe of eggs followed by Availa-Fe and $FeSO_4$. Increasing supplementary Fe level more than 100 ppm was not effective in Fe-Met and Availa-Fe treatments. Average Fe enrichment of 18% was achieved after feeding Fe-Met-100 for 15 d. In conclusion, enrichment of Fe in egg could be effectively achieved by supplementation of Fe-Met-100 for 15 d.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.46-53
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• 1993

The kinetic and equilibrium characteristics of copper extraction by salicylaldoxime in chloroform and benzene were investigated. Equilibrium constants such as dissociation constant, distribution coefficient of salicylaldoxime and stability constant, distribution coefficient and molar extinction coefficient of oxime-Cu chelate were determined from absorbance. Extracted species of Cu-chelate were found to be ${\bar{CuR_2}}$. Overall initial extraction rate of copper by salicylaldoxime in chloroform was expressed by the following equation : $R=k[Cu^{2+}]{\bar{[HR]}}^{0.5}/[H^+]^{0.4}$.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.905-908
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• 2000

Second-order rate constants have been measured spectrophotometrically for the hydrolysis of p-nitrophenyl ac-etate (PNPA) and p-nitrophenyl diphenylphosphinate (PNPDPP) with MO42- (M = Cr, Mo and W) in phos-phate buffer (pH = 8.00) at 35.0 $^{\circ}C.$ Thes e MO42- species exhibit large catalytic effect in the hydrolysis of PNPA and PNPDPP except WO42- in the reaction with PNPA. The catalytic effect of these MO42- species has been observed to be much more significantin the hydrolysis of PNPDPP than in the hydrolysis of PNPA. Since the smallest CrO42-would be most highly solvated by H2O molecules, CrO42- is expected to exhibit the least catalytic effect, if solvation effect is the most important factor. However, in fact, CrO42- shows the highest cat-alytic effect toward PNPA, indicating that solvation effect is not solely responsible for the catalytic effect. The most basic CrO42- shows the highest catalytic effect, while the least basic WO42- is least reactive toward PNPA, indicating that the basicity of MO4 2- might bean important factor. However, in the hydrolysis of PNPDPP, no correlation is observed between the basicity and catalytic effect, suggesting thatbasicity alone can not be re-sponsible for the catalytic effect shown by the MO42- species. Formation of a chelate is suggested to be respon-sible for the high catalytic effect of MO42- in the hydrolysis reaction of PNPA and PNPDPP. The formation of chelate is considered to be more suitable for the reaction with PNPDPP than with PNPA based on the larger catalytic effect observed in the reaction with PNPDPP than with PNPA.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.355-363
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• 2018

A novel $N_3S_1$ chelate, Pro-Lys-Cys (PKC) to cyclic RGD to radiolabel with $^{99m}Tc$ was conjugated in an effort to decrease the high intestinal accumulation observed for $^{99m}Tc$-labeled PGC-RGD. The target specificity of the resulting PKC-RGD was similar to that of PGC-RGD as determined by a cell binding assay and a competition binding assay. The $^{99m}Tc$ radiolabeling of PKC-RGD resulted in radiochemical yields of 98% under mild conditions at high specific activities. Biodistribution data in normal mice clearly showed a significant decrease in intestinal uptake at 2 h postinjection for the $^{99m}Tc-PKC-c$ (RGDyK) compared to the $^{99m}Tc-GC-c$ (RGDyK) (from $19.65%ID{\cdot}g^{-1}$ to $7.31%ID{\cdot}g^{-1}$ for the GI tract). The $^{99m}Tc-PKC-c$ (RGDyK) biodistribution was also shown by a higher retention of radioactivity in the whole body, but with kidney accumulation over 8-fold higher than observed with $^{99m}Tc-PGC-c$ (RGDyK) at 2 h ($12.62%ID{\cdot}g^{-1}$ for PKC-RGD and $1.54%ID{\cdot}g^{-1}$ for PGC-RGD, respectively). These results show that the biodistribution may be altered especially concerning lipophilicity resulting in renal rather than hepatobiliary excretion. This comparative study made it possible to explore the effects of lipophilicity on the biodistribution of $^{99m}Tc$-labeled c (RGDyK) through the use of different tripeptide $N_3S_1$ chelators. Therefore, $^{99m}Tc-PKC-c$ (RGDyK) may be an attractive alternative for the in vivo imaging of integrin receptors.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.10
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• pp.1501-1505
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• 2008

A broiler experiment was conducted to compare the effects of duration and level of iron-methionine chelate (Fe-Met) supplementation on the iron, copper (Cu) and zinc (Zn) content of broiler meat. Two hundred and fifty hatched Ross broiler chickens were randomly assigned to 5 dietary treatments. Each treatment had 5 replicates of 10 birds (5 males and 5 females) each. Birds were housed in raised floor batteries and fed traditional broiler diets ad libitum for 5 weeks. Dietary treatments were as follows: Control and two levels of Fe-Met (100 or 200 ppm in Fe) supplemented for either the whole period (0-5 wk) or grower period (4-5 wk). Production performance was not significantly affected by treatments. Iron content in the muscles (breast, leg and wing) and organs (liver and spleen) were significantly (p<0.05) increased as the level and duration of Fe-Met supplementation increased. The highest concentration of iron was shown in Fe-Met 200 fed for the whole period. Liver contained the highest amount of iron followed by spleen, leg muscle, wing muscle and breast muscle. Supplementation of Fe-Met 200 for the grower period resulted in higher iron concentration in liver and spleen than supplementation of Fe-Met 100 for the whole period. However, the same treatment resulted in lower iron concentration in muscles (breast, leg and wing) than the treatment of Fe-Met 100 for the whole period. In order to achieve the highest iron enrichment in the muscles, Fe-Met should be supplemented at 200 ppm in Fe for the whole period (5 wks). Fe-Met supplementation increased copper concentration in all muscles and organs except wing muscle. Zinc concentration decreased in breast and wing muscle but tended to increase in leg muscle, liver and spleen by Fe-Met 200 supplementation. Color of muscle was not significantly affected by Fe-Met treatments. However, redness of leg and breast muscle, and yellowness of leg and breast muscle tended to increase by supplementation of Fe-Met for the whole period. It was concluded that iron content of broiler meat can be effectively enriched by supplementation of 200 ppm of Fe as Fe-Met for 5 wks.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.879-888
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• 1992

Separation of the optical isomers of free amino acids by a reversed phase high performance liquid chromatography has been studied by adding a copper(II) complex of L-proline or L-proline derivatives (hydroxy-L-proline, N-benzyl-L-proline, p-xylenyl-L-proline, p-xylenyl-hydroxy-L-proline) in the mobile phase. An OPA postcolumn detection system was used for the detection of amino acids. The chromatographic properties for the free amino acids were discussed in terms of the pH, the kinds and concentration of chelate or organic modifier. The retention behaviors of the free amino acids were considerably different from, those of DNS-amino acids or DABS-amino acids. The enantioselectivity of the free amino acids was better than that of derivatized amino acids. The enantioselectivity between the optical isomers observed by use of the Cu(II)-p-xylenyl-L-proline chiral cheleate was the best among the several copper(II) chelate. A separation mechanism could be illustrated not only by the hydrophobic interaction of the diastereomer with stationary phase but also by the steric effect of the ligand exchange reaction between the free-amino acids and copper chelate.

• YAKHAK HOEJI
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• v.39 no.1
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• pp.48-54
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• 1995

Coupling of tetracycline(Tc) to dithiocarbamate chitosan(DTCC) via chelate bond was investigated varying reaction time, concentration, temperature, pH, and Ca(II)/Tc ratio. The amount of Tc bound to matrix increased to give a maximum and decreased as the reaction proceeded. The degree and rate of dissociation of Tc complex were affected by the reaction temperature, and pH. By running the reaction at low temperature and pH, the degree of dissociation was greatly diminished. Properties of drug-release from DTCC-Ca(II)-Tc complex were studied by batch- and flow-method and release of Tc and CA(II) by flow method followed nearly zero-order. DTCC-Ca(II)-Tc showed very prolonged antimicrobial activity compared to that of free Tc.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.121-128
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• 2011

This study was conducted to investigate the effects of dietary supplementation of Cu-sulfate, Cu-methionine chelate (Cu-Met) and Cu-soy proteinate (Cu-SP) on the performance, blood parameters and mineral contents of muscle. It was conducted with a total of 1,000 one d old broilers chickens (Ross$^{(R)}$) which were assigned to four dietary treatments; Control, Cu sulfate (200 ppm Cu as $CuSO_4{\cdot}5H_2O$), Cu-Met (200 ppm Cu as Cu-methionine chelate), Cu-SP (200 ppm Cu as Cu-soy proteinate). There were significant differences (p<0.05) among treatments in weight gain. Weight gain of Cu treated groups were higher than the control during 3~5 wk. There were significant differences (p<0.05) among treatments in feed intake during 0~3 wk. Cu-Met was significantly (p<0.05) lower than the control but the differences among Cu treatments were not significant. There were significant differences (p<0.05) among treatments in feed conversion rate (FCR). Cu treated groups were lower than the control during the whole period. Production efficiency factor (PEF) was significantly higher (p<0.01) in Cu treated groups than the control. Nutrient availabilities of diets were not significantly different among the treatments. The count of white blood cell (WBC) and eosinophil (EO) were lower in Cu-SP treatment than in the control. Copper concentration in the liver was significantly (p<0.01) higher in Cu treated groups than the control. Zinc concentration in the breast and wing muscle was lower in Cu treated and that of leg muscle was higher in Cu-Met than the control. The result of this experiment showed that Cu supplementation at the level of 200 ppm as Cu sulfate, Cu-Met and Cu-SP improves weight gain (4~5 wk), FCR and PEF. Differences among Cu sources were not significant.