Gyoung-Ja Lee

Anti-oxidant and natural killer cell activity of Korean red ginseng (Panax ginseng) and urushiol (Rhus vernicifera Stokes) on non-alcoholic fatty liver disease of rat.

Anti-oxidative and immunologic effects of the Korea red ginseng (KRG; Panax ginseng) and urushiol (Rhus vernicifera Stokes) on non-alcoholic fatty liver disease (NAFLD) were evaluated. Forty-five rats (five Long-Evans Tokushima Otsuka and 40 Otsuka Long-Evans Tokushima Fatty [OLETF] rats) received chew diets for 10months; after this period. The OLETF rats were divided into the following four groups according to diet for 2months: NAFLD (chew), KRG (chew+KRG [200mg/kg/day]), urushiol (chew+urushiol [0.5mg/kg/day]), and ursodeoxycholic acid (UDCA) (chew+UDCA [15mg/kg/day]) groups. Liver function, lipid profiles and anti-oxidant activity of liver and serum, natural killer (NK) cell activity, and pathology were compared. In KRG and urushiol groups, the level of serum triglyceride ([302.0±70.4 and 275.2±63.8] vs. 527.7±153.3mg/dL) were lower compared with that of NAFLD group (p<0.05). The levels of HDL-cholesterol (liver tissue: [4.8±0.2 and 4.8±0.5] vs. 4.2±0.2mg/g) and NK cell activity ([3485±910 and 3559±910] vs. 2486±619 counts) were significantly higher than those of the NAFLD group (p<0.001). Inflammation with neutrophil infiltration was observed in only two rats in the NAFLD group. These results suggest that 2months of oral KRG or urushiol administration improves lipid profiles and stimulates NK cell activity, while inhibiting steatohepatitis in OLEFT rats.

Mixed Diffusion and Charge-Transfer-Controlled Oxygen Reduction on Dense La1 − x Sr x Co0.2Fe0.8O3 − δ Electrodes with Various Sr Contents

The oxygen reduction mechanism of dense mixed-conducting La 1-x Sr x Co 0.2 Fe 0.8 O 3-δ (LSCF) electrodes with various Sr contents was investigated by employing ac-impedance spectroscopy and potentiostatic current transient (PCT) technique. From the analyses of the ac-impedance spectra and the cathodic PCTs measured on the electrodes as functions of electrode thickness k and oxygen partial pressure pO 2 , it is confirmed that the overall oxygen reduction reaction mainly proceeds by oxygen vacancy diffusion through the electrode coupled with the charge-transfer reaction on the electrode surface. Furthermore, as Sr cont decrease in the diffusion resistance R d due to higher diffusivity of oxygen vacancy DV O is more predomina that in the charge-transfer resistance R ct due to the larger electrochemically active area A ea . The smaller values of R d and increasing Sr content lead to the higher initial current I ini , higher steady-state current I st , and shortened time to reach steat current t st in the cathodic PCTs. From the analyses of the impedance spectra combined with the cathodic PCTs measured on The electrodes cathodically polarized for various times, it is suggested that the decomposition of SrO on the electrode surface by the cathodic polarization enhances A ea , resulting in the kinetic facilitation of the charge-transfer reaction at the electrode/gas interface.

Hierarchical assembly of diphenylalanine into dendritic nanoarchitectures.

Highly ordered, multi-dimensional dendritic nanoarchitectures were created via self-assembly of diphenylalanine from an acidic buffer solution. The self-similarity of dendritic structures was characterized by examining their fractal dimensions with the box-counting method. The fractal dimension was determined to be 1.7, which demonstrates the fractal dimension of structures generated by diffusion limited aggregation on a two-dimensional substrate surface. By confining the dendritic assembly of diphenylalanine within PDMS microchannels, the self-similar dendritic growth could be hierarchically directed to create linearly assembled nanoarchitectures. Our approach offers a novel pathway for creating and directing hierarchical nanoarchitecture from biomolecular assembly.

Valeric acid induces cell cycle arrest at G1 phase in CHO cell cultures and improves recombinant antibody productivity.

To find a more effective chemical reagent for improved monoclonal antibody (mAb) production, eight chemical reagents (curcumin, quercein, DL-sulforaphane, thymidine, valeric acid, phenyl butyrate, valproic acid, and lithium chloride) known to induce cell cycle arrest were examined individually as chemical additives to recombinant CHO (rCHO) cell cultures producing mAb. Among these chemical additives, valeric acid showed the best production performance. Valeric acid decreased specific growth rate (μ), but increased culture longevity and specific mAb productivity (qmAb ) in a dose-dependent manner. The beneficial effect of valeric acid on culture longevity and qmAb outweighed its detrimental effect on μ, resulting in 2.9-fold increase in the maximum mAb concentration when 1.5 mM valeric acid was added to the cultures. Furthermore, valeric acid did not negatively affect the mAb quality attributes with regard to aggregation, charge variation, and galactosylation. Unexpectedly, galactosylation of the mAb increased by the 1.5 mM valeric acid addition. Taken together, the results obtained here demonstrate that valeric acid is an effective chemical reagent to increase mAb production in rCHO cells.

Round-robin test on thermal conductivity measurement of ZnO nanofluids and comparison of experimental results with theoretical bounds

Ethylene glycol (EG)-based zinc oxide (ZnO) nanofluids containing no surfactant have been manufactured by one-step pulsed wire evaporation (PWE) method. Round-robin tests on thermal conductivity measurements of three samples of EG-based ZnO nanofluids have been conducted by five participating labs, four using accurate measurement apparatuses developed in house and one using a commercial device. The results have been compared with several theoretical bounds on the effective thermal conductivity of heterogeneous systems. This study convincingly demonstrates that the large enhancements in the thermal conductivities of EG-based ZnO nanofluids tested are beyond the lower and upper bounds calculated using the models of the Maxwell and Nan et al. with and without the interfacial thermal resistance.

Precisely Determining Ultralow level UO22+ in Natural Water with Plasmonic Nanowire Interstice Sensor

Uranium is an essential raw material in nuclear energy generation; however, its use raises concerns about the possibility of severe damage to human health and the natural environment. In this work, we report an ultrasensitive uranyl ion (UO22+) detection method in natural water that uses a plasmonic nanowire interstice (PNI) sensor combined with a DNAzyme-cleaved reaction. UO22+ induces the cleavage of DNAzymes into enzyme strands and released strands, which include Raman-active molecules. A PNI sensor can capture the released strands, providing strong surface-enhanced Raman scattering signal. The combination of a PNI sensor and a DNAzyme-cleaved reaction significantly improves the UO22+ detection performance, resulting in a detection limit of 1 pM and high selectivity. More importantly, the PNI sensor operates perfectly, even in UO22+-contaminated natural water samples. This suggests the potential usefulness of a PNI sensor in practical UO22+-sensing applications. We anticipate that diverse toxic metal ions can be detected by applying various ion-specific DNA-based ligands to PNI sensors.

Cellular Uptake Behavior of Doxorubicin‐Conjugated Nanodiamond Clusters for Efficient Cancer Therapy

This paper describes the design and fabrication of doxorubicin (Dox)-conjugated nanodiamond (ND) clusters with controlled sizes and cellular uptake behaviors of free Dox and Dox-conjugated ND clusters. The ND clusters with an average size of 45.84 nm exhibited a higher amount of cellular uptake as compared to the ND clusters with larger sizes. The amount of Dox taken up as free Dox increased initially and then decreased over time. In contrast, the amount of Dox taken up as Dox-ND clusters continuously increased and reached a plateau, resulting in high ablation efficiency. At the same Dox concentration, the cell viabilities after treatment with free Dox and Dox-ND clusters were 26.38 and 5.31%, respectively. The Dox-ND clusters potentially could be employed as efficient drug carriers for efficient cancer therapy.

Decreased Total Antioxidant Activity in Major Depressive Disorder Patients Non-Responsive to Antidepressant Treatment

Objective This study aimed to evaluate the total antioxidant activity (TAA) in patients with major depressive disorder (MDD) and the effect of antidepressants on TAA using a novel potentiometric method. Methods Twenty-eight patients with MDD and thirty-one healthy controls were enrolled in this study. The control group comprised 31 healthy individuals matched for gender, drinking and smoking status. We assessed symptoms of depression using the Hamilton Depression Rating Scale (HAMD) and the Beck Depression Inventory (BDI). We measured TAA using potentiometry. All measurements were made at baseline and four and eight weeks later. Results There was a significant negative correlation between BDI scores and TAA. TAA was significantly lower in the MDD group than in controls. When the MDD group was subdivided into those who showed clinical response to antidepressant therapy (response group) and those who did not (non-response group), only the non-response group showed lower TAA, while the response group showed no significant difference to controls at baseline. After eight weeks of antidepressant treatment, TAA in both the response and non-response groups was similar, and there was no significant difference among the three groups. Conclusion These results suggest that the response to antidepressant treatment in MDD patients might be predicted by measuring TAA.

A Study on Thermal Properties of Ethylene Glycol Containing Copper Oxide Nanoparticles

【In the present work, ethylene glycol-based (EG) copper oxide nanofluids were synthesized by pulsed wire evaporation method. In order to explode the pure copper wire, high voltage of 23 kV was applied to the both ends of wire and argon/oxygen gas mixture was used as reactant gas. EG-based copper oxide nanofluids with different volume fraction were prepared by controlling explosion number of copper wire. From the transmission electron microscope (TEM) image, it was found that the copper oxide nanoparticles exhibited an average diameter about 100 nm with the oxide layer of 2~3 nm. The synthesized copper oxide consists of CuO/

Experimental Study on Ion Penetration into Pores with Pore Fractality at Carbon Electrode for EDLC

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