• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.513-521
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• 1995

Background: Nucleolar organizer regions(NORs) are chromosomal segments encoding for ribosomal RNA and associated with argyrophilic nonhistone protein. Ribosomal RNA genes ultimately direct ribosome and protein synthesis, and it has been suggested the numbers of NORs detected in the cell may reflect nuclear and cellular activity. This study was performed to evaluate the applicability of AgNORs to the diagnosis of squamous cell carcinoma of the lung. Method: The one step silver methods(AgNORs) was used to stain NORs in the routinely processed, formalin fixed, paraffin embedded sections of 36 cases of squamous cell carcinoma of the lung obtained by surgical resection of primary tumor. In each specimen, 100 tumor cells and 100 normal cells adjacent to the tumor chosen at random were examined under an oil immersion lens at a magnification of ${\times}1000$. The mean number of AgNORs per nucleus was calculated for each specimen. Results: The mean number of AgNORs per nucleus(mAgNORs) of normal bronchial epithelium and squamous cell carcinoma of the lung was $1.74{\pm}0.25$ and $4.05{\pm}0.80$, respectively. The difference of mAgNOR between normal and tumor tissue was statistically significant(p<0.001). There was no statistical difference among tumors of different stages. The difference of mAgNOR between normal and tumor tissue was statistically significant in each TNM stage(p<0.05). Conclusion: Mean AgNOR count may be used as a useful marker for the differential diagnosis of benignancy and malignancy, and proliferative activity of the cell in squamous cell carcinoma of the lung. But there was no statistical difference in mean AgNOR count among tumors of different surgical stages. Further studies for the application of mAgNORs to the diagnosis of other histologic types and cytologic specimens of the lung cancer are needed.

• Elastomers and Composites
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• v.42 no.2
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• pp.112-118
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• 2007

An HRP immobilized carbon paste electrode, which was bound by EPDM, was newly fabricated and its electrochemical properties were investigated for the purpose of validating the new possibility for the practical use of biosensor. In the experimental range of substrate concentration, Lineweaver-Burk plot of the signal showed a good linearity. This means that HRP was embedded effectively to preserve its identity in the bulk of composite electrode materials and EPDM is a recommendatory binder. When the electrode was run at low operating potential($0.0\sim-1.0$ V vs. Ag/AgCl), it showed a high sensitivity and a good reproducibility. Especially the mechanical stability of the dried rubber was a remarkable breakthrough to get over a difficulty in putting the carbon-paste electrode bound with silicon oil to real use.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.394.2-394.2
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• 2014

We fabricated highly transparent and flexible Ti doped In2O3 (TIO)/Ag nanowire(NW)/TIO (TAT) multilayer electrodes by linear facing target sputtering (LFTS) and brush-painting for used as flexible for anode organic solar cells(FOSCs). The characteristics of TAT transparent anode as a function of number of brush-painting cycles was also investigated. At optimized conditions we achieved highly flexible TAT multilayer electrodes with a low sheet resistance of $9.01{\Omega}/square$ and a high diffusive transmittance more than 80% in visible region as well as superior mechanical stability. The effective embedment of the Ag NW network between top and bottom TIO films led to a metallic conductivity, high transparency. Based on FE-SEM HRTEM, and XRD analysis, we can find that the Ag NW network was effectively embedded between top and bottom TIO layers due to good flexibility of Ag NW, the TAT multilayer showed superior flexibility than single TIO layer. Successful operation of FOSCs with high power conversion efficiency of 3.01% indicates that TAT hybrid electrode is a promising alternative to conventional ITO electrode for high performance FOSCs.

• The Journal of Korean Physical Therapy
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• v.12 no.1
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• pp.1-7
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• 2000

The purpose of this study was to determine the effect of microamperage electrical stimulation on the number of argyrophilic nucleolar organizer region (AgNOR) in rat skin. Twenty four male Sprague-Dawley rats were divided into electrical stimulation and control group. Bach animals hair on the back was removed. The electrical stimulation group received an positive rectangular positive electrical stimulation with $500{\mu}A$, while the control group was given the same treatment without electricity. The rats were sacrificed at 4 and 7 day of stimulation, respectively. The biopsy specimens were fixed in formalin, embedded in paraffin and stained with silver nitrate. The AgNOR were counted using a light microscope and computerized image analysis system and calculated as the mean number of AgNOR per nucleus in the epidermal keratinocyte. In control skin, the mean AgNOR count of epidermal keratinocyte at 4 and 7 day were 1.67 and 1.72, whereas electrical stimulated rat had mean AgNOR counts of 2.0 and 2.14, respectively. A Student's t-test showed a significantly higher mean AgNOR number at 4 ana 7 day in the electrical stimulated rats than control rats (p<0.05). The microamperage electric current stimulation increased the epidermal AgMOR expression in incisional wound skin. These results suggest that the microamperage electrical stimulation may promote migration and proliferative activity of epidermal keratinocyte in surgical wound.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.29-29
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• 1999

The synthesis of layered structures on the nanometer scale has become essential for continued improvements in the operation of various electronic and magnetic devices. Abrupt metal-metal interfaces are desired for applications ranging from metallization in semiconductor devices to fabrication of magnetoresistive tunnel junctions for read heads on magnetic disk drives. In particular, characterizing the interface structure between various transition metals (TM) and aluminum is desirable. We have used the techniques of MeV ion backscattering and channeling (HEIS), x-ray photoemission (ZPS), x-ray photoelectron diffraction(XPD), low-energy ion scattering (LEIS), and low-energy electron diffraction(LEED), together with computer simulations using embedded atom potentials, to study solid-solid interface structure for thin films of Ni, Fe, Co, Pd, Ti, and Ag on Al(001), Al(110) and Al(111) surfaces. Considerations of lattice matching, surface energies, or compound formation energies alone do not adequately predict our result, We find that those metals with metallic radii smaller than Al(e.g. Ni, Fe, Co, Pd) tend to form alloys at the TM-Al interface, while those atoms with larger atomic radii(e.g. Ti, Ag) form epitaxial overlayers. Thus we are led to consider models in which the strain energy associated with alloy formation becomes a kinetic barrier to alloying. Furthermore, we observe the formation of metastable fcc Ti up to a critical thickness of 5 monolayers on Al(001) and Al(110). For Ag films we observe arbitrarily thick epitaxial growth exceeding 30 monolayers with some Al alloying at the interface, possible driven by interface strain relief. Typical examples of these interface structures will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.597-600
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• 2003

Bi-2223/Ag HTS wires have been fabricated by the PIT(powder in tube)process. Intermediate annealing was carried out to increase the homogenization and uniformity of the superconducting filaments embedded in the silver matrix during the deformation process that is important to sustain the engineering critical current density in long superconducting wire. Intermediate annealing act to release the deformation hardening of the superconducting wires during drawing process. Rolling parameters were investigated to roll the superconducting tapes with uniform thickness, width and winding tensions. Critical current of 60 m long superconducting tapes was measured 54.3 A continuously after final sintering heat treatment. The phase analysis of Bi-2223/Ag superconducting tapes are examined by the XRD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.403-404
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• 2005

The conductivity of diamond like carbon films embedded with silver nanoclusters were investigated as a function of silver concentrations in the film. By increasing the concentration of silver in the film from 0 to 20 at% the conductivity varied from $10^{-13}$ to $10^2\;ohm^{-1}\;cm^{-1}$. The data have been discussed within the model of a dielectric matrix containing conductive inclusions. The conductivity data analysis using percolation theory has been showed that percolation threshold occurred at Ag percentage in the film $x_c$ =5 at %.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7675-7679
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• 2013

Background: A missense mutation in exon 7 (R249S) of the p53 tumor suppressor gene is characteristic of aflatoxin B1 (AFB1) exposure. AFB1 is believed to have a synergistic effect on hepatitis virus B (HBV) carcinogenesis. However, results of studies comparing R249S prevalence among patients are conflicting. The aim of this study was to determine the prevalence of the R249S mutation in hepatocellular carcinoma (HCC) patients with or without positive HBsAg. Materials and Methods: Paraffin embedded liver tissues were obtained from 124 HCC patients who underwent liver resection and liver biopsy in King Chulalongkorn Memorial Hospital. Restriction fragment length polymorphism (RFLP) was utilized to detect the R249S mutation. Positive results were confirmed by direct sequencing. Results: Sixty four (52%) patients were positive for HBsAg and 18 (15%) were anti-HCV positive. 12 specimens tested positive by RFLP. Ten HCC patients (8.1%) were confirmed to be R249S positive by Sanger sequencing (AGG to AGT). Out of these 10, six were HBsAg positive, and out of the remaining 4, two were anti-HCV positive. The R249S prevalence among HCC patients with positive HBsAg was 9.4% compared to 6.7% for HBsAg negative samples. Patients with the R249S mutation were younger ($55{\pm}10$ vs $60{\pm}13$ year-old) and tended to have a more advanced Edmonson-Steiner grade of HCC, although differences did not reach statistical significance. Conclusions: Our study shows moderate prevalence of aflatoxin B1-related p53 mutation (R249S) in HCC with or without HBsAg. HBsAg positive status was not associated with R249S prevalence.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.8-14
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• 1995

The magnetic properties of an $Fe_{87}Zr_{7}B_{5}Ag_{1}$(at.%) amorphous alloy have been investigated as a function of annealing temperatures to clarify its application potential as a core material for high-frequency use by adding a small amount of insoluble element of Ag. A new excellent soft magnetic material was developed. The amorphous alloy produced by relatively low temperature annealing at $T_{a}=400^{\circ}C$ exhibited very high initial permeability$(\mu_{i})$ of 288,000 at 1kHz and 2mOe, very low coercivity$(H_{c})$ of 15mOe and low core loss$(W_{c})$ of 50W/kg at 100kHz and 1,000G which is comparable with Co-based amorphous alloys, respectively. It is notable that the values obtained in the present study are the best magnetic properties among various kinds of Fe-based soft amorphous materials reported up to date. The reasons for the achievement of good soft magnetic properties are presumably due to the homogeneous formation of very fine $\alpha$-Fe clusters with the size of 2~3nm in an amorphous matrix, which can be deduced from the increase of resistivity and the TEM observation. The very fine $\alpha$-Fe clusters embedded in an amorphous matrix had a great influence on reduction of magnetostriction and refinement of magnetic domain.

• Analytical Science and Technology
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• v.29 no.1
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• pp.35-42
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• 2016

A new nano-composite carbon ink for the development of disposable dopamine (DA) biosensors based on screen-printed carbon electrodes (SPCEs) is introduced. The method developed uses SPCEs coupled with a tyrosinase modified nano-composite carbon ink. The ink was prepared by an “in-house” procedure with reduced graphene oxide (rGO), Pt nanoparticles (PtNP), and carbon materials such as carbon black and graphite. The rGO-PtNP carbon composite ink was used to print the working electrodes of the SPCEs and the reference counter electrodes were printed by using a commercial Ag/AgCl ink. After the construction of nano-composite SPCEs, tyrosinase was immobilized onto the working electrodes by using a biocompatible matrix, chitosan. The composite of nano-materials was characterized by X-ray photoelectron spectroscopy (XPS) and the performance characteristics of the sensors were evaluated by using voltammetric and amperometric techniques. The cyclic voltammetry results indicated that the sensors prepared with the rGO-PtNP-carbon composite ink revealed a significant improvement in electro-catalytic activity to DA compared with the results obtained from bare or only PtNP embedded carbon inks. Optimum experimental parameters such as pH and operating potential were evaluated and calibration curves for dopamine were constructed with the results obtained from a series of amperometric detections at −0.1 V vs. Ag/AgCl. The limit of detection was found to be 14 nM in a linear range of 10 nM to 100 µM of DA, and the sensor’s sensitivity was calculated to be 0.4 µAµM⁻¹cm⁻².