• Korean Journal of Materials Research
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• v.19 no.6
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• pp.319-324
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• 2009

The deposition behavior and structural and magnetic properties of electroless Co-B and Co-Fe-B deposits, as well as the amorphous ribbon substrates, were investigated. These Co-based alloy deposits exhibited characteristic polycrystalline structures and surface morphology and magnetic properties that were dependent on the type of amorphous substrates. The catalytic activity sequence of the amorphous ribbon electrodes for anodic oxidation of DMAB was estimated from the current density-potential curve in the anodic partial electrolytic bath that did not contain the metal ions. Both the deposition rate and potential in the initial region were obtained in order of the catalytic activity, depending on the alloy compositions of the substrates. The deposition rate linearly varied against the deposition time. The initial deposition potential may have also determined the structural and magnetic properties of the deposit based on the thickness of ${\mu}m$ order. Furthermore, a basic study of the electroless deposition processes on an amorphous ribbon substrate has been carried out in connection with the structural and magnetic properties of the deposits.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1357-1360
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• 2008

Propionibacterium acnes is the predominant organism in sebaceous regions of the skin and is thought to play an important role in the pathogenesis of inflamed lesions. Antibacterial compounds against P. acnes were isolated from the ethanol extract of Kaempferia pandurata Roxb. and identified as panduratin A and isopanduratin A. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panduratin A for P. acnes were 2 and $4{\mu}g/mL$, respectively, while those of isopanduratin A were 4 and $8{\mu}g/mL$, respectively. The time-dependent killing effect showed that panduratin A and isopanduratin A completely inhibited the growth of P. acnes at 4 and $8{\mu}g/mL$ in 48 hr, respectively. Panduratin A and isopanduratin A demonstrated high antibacterial activities not only against P. acnes but also other skin microorganisms. The results suggest that panduratin A and isopanduratin A could be employed as natural antibacterial agents to inhibit the growth of acne and skin disease causing microorganisms.

• Journal of Nutrition and Health
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• v.24 no.5
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• pp.431-441
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• 1991

To investigate the influence of age and dietary fat level on the immune function and the growing potential of the fibroblast cells, male rats of 2 month, 6 month and 30 month of age were fed either 6% or 30% fat diet for 16 weeks. The weight of thymus decreased linearly with increasing age. And this age-dependent degeneration of thymus was delayed in rats fed low fat diets. The blastogenesis of spleen lymphocytes to PHA, ConA, and PWM was decreased with increasing age, however, no effect of dietary fat level was observed. The age-related decline in ratios of PHA/ConA response may suggest that T suppressor cell activity increases with age. In cell culture system, lung fibroblast cells from 30M rats showed lower plating efficiency. longer doubling time. and shorter cumulative doubling potential than those from 2M or 6M animals. Also. the morphology of fibroblasts from 30M rats was tended to be rouned rather than flattened and more variable in size and being generally larger. wherease those from 2M and 6M rats were uniform in size and adhered tightly to the culture vessel in ordered arrays. Therefore fibroblast cell culture system tried in this study reflects the changes of cellular aging.

• Nutrition Research and Practice
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• v.2 no.4
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• pp.317-321
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• 2008

Macrophages play a key role in iron metabolism by recycling iron through erythrophagocytosis. Ferroportin-l (FPN1) is a transporter protein that is known to mediate iron export from macrophages. Since divalent metals often interact with iron metabolism, we examined if divalent metals could regulate the expression of FPN1 in macrophages. J774 macrophage cells were treated with copper, manganese, zinc, or cobalt at 10, 50, or $100\;{\mu}M$ for 16 to 24 h. Then, FPN1 mRNA and protein levels were determined by quantitative real-time PCR and Western blot analyses, respectively. In addition, effects of divalent metals on FPN1 promoter activity were examined by luciferase reporter assays. Results showed that copper significantly increased FPN1 mRNA levels in a dose-dependent manner. The copper-induced expression of FPN1 mRNA was associated with a corresponding increase in FPN1 protein levels. Also, copper directly stimulated the activity of FPN1 promoter-driven reporter construct. In contrast, manganese and zinc had no effect on the FPN1 gene expression in J774 cells. Interestingly, cobalt treatment in J774 cells decreased FPN1 protein levels without affecting FPN1 mRNA levels. In conclusion, our study results demonstrate that divalent metals differentially regulate FPN1 expression in macrophages and indicate a potential interaction of divalent metals with the FPN1-mediated iron export in macrophages.

• Preventive Nutrition and Food Science
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• v.2 no.3
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• pp.236-240
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• 1997

A crude extract of Smphytum officinale L. (comfrey) was for its ability to inhibit he growth of hepatocellular carcinoma cells and expression of the insulin-like growth factor I (IGF-II) gene. The DNA synthesis of hepatocellular carcinoma cell lines, Hep G2, Hep 3B, and PLC/PRF/5 was inhibited by a crude extract of Smphytum officinale in both a time- and a dose-dependent manners. This plant extract also inhibited expression of the IGF-II gene. Since IGF-II exerts a mitogenic effect on Hep G2 cells, these results suggest that the growth inhibition by Symphytum officinale extract is, in part, mediated through the inhibition of IGF-II gene expression.

• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.167-173
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• 1997

The inhibitory effects of kale juice on the growh and DNA incorporation of human cancer cells, using HT-29 colon cancer cells, MG-63 osteosarcoma cells, AGS gastric adenocarcinoma cells and K-562 leukemia cells, were studied. The growth of human cancer cells were inhibited in the presence of kale juice (10, 20 nd 40$\mu$l/ml) and the effects were the juice concentration- and incubation time-dependent up to 6 days. When 20$\mu$l/ml of kale juice was added to the media of HT-29, MG-63, AGS and K-562 cancer cells, the cell growth after 6 or 4 days of incubation was retarded by 83~95% of control group. Morphological changes of HT-29 colon cancer cells wre studied under inverted microscope. As the concentration of kale juice increased up to 20$\mu$l/ml, degree of cell aggregation was decreased. Moreover, the DNA incorporation o AGS gastric adenocarcinoma cells and MG-63 osteosarcoma cells which were labeled with [$^3$H] thymidine was significantly reduced after 2 days of incubation at 37$^{\circ}C$ with kale juice. Therefore, we concluded that kale juice strongly decreased the growth of various human cancer cells.

• Advances in nano research
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• v.8 no.1
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• pp.13-24
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• 2020

In this paper, for the first time based on the nonlocal strain gradient theory the effect of size dependency in torsional vibration of bi-direction functionally graded (FG) nonlinear nano-cone is study. The material properties were assumed to vary according to the arbitrary function in radial and axial directions. The Navier equation and boundary conditions of the size-dependent bidirectional FG nonlinear nano-cone were derived by Hamilton's principle. These equations were solved by employing the generalized differential quadrature method (GDQM). The presented model can turn into the classical model if the material length scale parameters are taken to be zero. The effects of some parameters, such as inhomogeneity constant, cross-sectional area parameter and small-scale parameters, were studied. As an essential result of this study can be stated that an FG nano-cone model based on the nonlocal elasticity theory behaves softer and based on the strain gradient theory behaves harder.

• Advances in nano research
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• v.7 no.6
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• pp.379-390
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• 2019

Putting emphasis on the effect of existence of porosity in the functionally graded materials (FGMs) on the dynamic responses of waves scattered in FG nanobeams resulted in implementation of a novel porosity-based homogenization method for FGMs and show its applicability in a wave propagation problem in the presence of axial pre-load for the first time. In the employed porosity-dependent method, the coupling between density and Young's moduli is included to consider for the effective moduli of the FG nanobeam by the means of a more reliable homogenization technique. The beam-type element will be modeled via the classical theory of beams, namely Euler-Bernoulli beam theory. Also, the dynamic form of the principle of virtual work will be extended for such nanobeams to derive the motion equations. Applying the nonlocal constitutive equations of Eringen on the obtained motion equations will be resulted in derivation of the nanobeam's governing equations. Depicted results reveal that the dispersion responses of FG nanobeams will be decreased as the porosity volume fraction is increased which must be noticed by the designers of advanced nanosize devices who are interested in employment of wave dispersion approach in continuous systems for specific goals.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.567-574
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• 1993

Mordant Red 19(MR19) is reduced at mercury electrode at -0.67 V vs. Ag/AgCl with two electrons per molecule in pH 9.2 buffer by differential pulse polarography and linear sweep voltammetry. The peak potential is dependent on the pH of solution. The exhaustive electrolysis, however, gives 4 electrons per molecule because of the disproportionation of the unstable hydrazo intermediate. The electrochemical reduction of lanthanide-MR19 complexes is observed at more cathodic potential than that of free ligand. The difference in peak potentials between complex and free ligand varies from 75 mV for $La^{3+}$ to 165 mV for $Tb^{3+}$ and increases with increasing the atomic number of lanthanide. The electrochemical reduction of lanthanide complexes with MR19 is due to the reduction of ligand itself, and it can be potentially useful as an indirect method for the determination of lanthanides. The shape of i-E curves and the scan rate dependence indicates the presence of adsorption and the adsorption was confirmed by potential double-step chronocoulometry and the effect of standing time. Also the surface excess of the adsorbed species and diffusion coefficients are determined. The composition of the complex is determined to be 1 : 2 by spectrophotometric and electrochemical methods.

• Earthquakes and Structures
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• v.2 no.4
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• pp.337-356
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• 2011

In this paper, cable-stayed bridges with single pylon and two equal side spans, with variations in geometry and span ranging from 120 m to 240 m have been studied. 3D models of the bridges considered in this study have been analysed using ANSYS. As the first step towards a detailed seismic analysis, free vibration response of different geometries is studied for their mode shapes and frequencies. Typical pattern of free vibration responses in different frequencies with change in geometry is observed. Further, three different seismic loading histories are chosen with various characteristics to find the structural response of different geometries under seismic loading. Effect of variation in pylon shape, cable arrangement with variation in span is found to have typical characteristics with different structural response under seismic loading. From the study, it is observed that the structural response is very much dependent on the geometry of the cable-stayed bridge and the characteristics of the seismic loading as well. Further, structural responses obtained from the study would help the design engineers to take decisions on geometric shapes of the bridges to be constructed in seismic prone zones.