• Journal of Korean Neurosurgical Society
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• v.39 no.6
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• pp.432-437
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• 2006

Objective : In order to establish the index of degeneration, the authors performed a histochemical study with Safranin-O staining and investigated the occurrence of apoptosis in the human intervertebral disc. Methods : Eighteen intervertebral disc specimens surgically extracted from the patients and two additional specimens from the autopsied cases were stained with Safranin-O for proteoglycan according to a standard protocol. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate- biotin nick end labeling[TUNEL] was used to detect the fragmented DNA known to be associated with apoptotic cell death and classification scheme was formulated for categorization of the degree of Safranin-O staining [normal, moderate reduction, faint] by modification of Makin's histological-histochemical grading. The Kruskal-Wallis H test and Chi-square test were used for statistical analysis. Results : The statistical results showed a significant difference in the mean age between "normal" Safranin-O staining group and the others [19.3 versus 55, 43.4, p=0021]. However, there was no statistically significant correlation between Safranin-O staining and MR grading of disc degeneration. Only six of eighteen surgical specimens and none in autopsies showed positive apoptotic cells in TUNEL staining. Conclusion : The determination of the degree of degeneration in surgically obtained disc tissue per se by histochemical staining or by the degree of apoptosis that corresponds to its morphologic change was not feasible.

• Restorative Dentistry and Endodontics
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• v.45 no.4
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• pp.54.1-54.16
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• 2020

Objectives: This study aimed to synthesize nanocrystals (NCs) of zinc oxide (ZnO) and calcium ion (Ca²⁺)-doped ZnO with different percentages of calcium oxide (CaO), to evaluate cytotoxicity and to assess the effects of the most promising NCs on cytotoxicity depending on lipopolysaccharide (LPS) stimulation. Materials and Methods: Nanomaterials were synthesized (ZnO and ZnO:xCa, x = 0.7; 1.0; 5.0; 9.0) and characterized using X-ray diffractometry, scanning electron microscopy, and methylene blue degradation. SAOS-2 and RAW 264.7 were treated with NCs, and evaluated for viability using the MTT assay. NCs with lower cytotoxicity were maintained in contact with LPS-stimulated (+LPS) and nonstimulated (-LPS) human dental pulp cells (hDPCs). Cell viability, nitric oxide (NO), and reactive oxygen species (ROS) production were evaluated. Cells kept in culture medium or LPS served as negative and positive controls, respectively. One-way analysis of variance and the Dunnett test (α = 0.05) were used for statistical testing. Results: ZnO:0.7Ca and ZnO:1.0Ca at 10 ㎍/mL were not cytotoxic to SAOS-2 and RAW 264.7. +LPS and -LPS hDPCs treated with ZnO, ZnO:0.7Ca, and ZnO:1.0Ca presented similar NO production to negative control (p > 0.05) and lower production compared to positive control (p < 0.05). All NCs showed reduced ROS production compared with the positive control group both in +LPS and -LPS cells (p < 0.05). Conclusions: NCs were successfully synthesized. ZnO, ZnO:0.7Ca and ZnO:1.0Ca presented the highest percentages of cell viability, decreased ROS and NO production in +LPS cells, and maintenance of NO production at basal levels.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.78-82
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• 1997

Surface swab samples from beef (188), pork (240) and chicken (95) carcasses were collected from slaughterhouse in Kangwon and Kyunggi areas from March through July 1996. The samples were examined on the level of E. coli biotype I relevant to fecal contamination due to unsanitary processing control and the existence of verocytotoxin-producing E. coli (VTEC). E. coli biotype I were confirmed from 38.8% of beef, 40.0% of pork, and 69.5% of chicken carcasses. Little variation was noted among three sampling points; rump, flank and neck of beef, ham, belly and jowls of pork. coli O157:H7 was only confirmed from 2 of 188 beef carcasses. E. coli biotype I. All the isolated E. coli O157 showed positive for vero cell cytotoxicity test. Isolation rate of E. coli O157 in summer was higher than in spring. In case of pork and chicken carcasses, E. coli O157 was isolated in summer only.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.136-140
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• 1992

The purpose of this research is to develop the lithium secondary battery. This paper describes the preparation, electrochemical properties of nontstoichiometric(NS)-$V_6O_{13}$ and characteristics of Li/$V_6O_{13}$ secondary battery. NS-$V_6O_{13}$ was prepared by thermal decomposition of $NH_4VO_3$ under Ar stream of 140ml/min~180ml/min flow rate. And then, this NS-$V_6O_{13}$ was used for cathode active material. Cathode sheet was prepared by compressing the composite of NS-$V_6O_{13}$, acetylene black(A.B) and teflon emulsion (T.E). Characteristics of the test cell are summarised as follows. Oxidation capacity of NS-$V_6O_{13}$ was about 20% less than its reduction capacity. A part of NS-$V_6O_{13}$ cathode active material showed irreversible reaction in early charge-discharge cycle. This phenomena seems to be caused by irreversible incoporation/discoporation of lithium cation to/from NS-$V_6O_{13}$ host. Discharge characteristics curve of Li/$V_6O_{13}$ cell showed 4 potential plateaus. Charge-discharge capacity was declined in the beginning of cycling and slowly increased in company with increasing of coulombic efficiency. Energy density per weight of $V_6O_{13}$ cathode material was as high as 522Wh/kg~765Wh/kg.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.262-268
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• 2009

We investigated the properties of inorganic diatomic films like silicon oxide ($SiO_2$) and zinc oxide (ZnO) and their composite films are packed as a passivation layer around Ca cells on glass substrates by using an electron-beam evaporation technique and rf-magnetron sputtering method. When these Ca cells are exposed to an ambient atmosphere, the water vapor penetrating through the passivation layers is adsorbed in the Ca cells, resulting in a gradual progress of transparency in the Ca cells, which can be represented by changes of the optical transmittance in the visible range. Compared with the saturation times for the Ca cells to become completely transparent in the atmosphere, the protection effects against permeation of water vapor are estimated for various passivation films. The thin composite films consist of$SiO_2$ and ZnO are found to show a superior protection effect from water vapor permeation compared with diatomic inorganic films like $SiO_2$ and ZnO. Also, this inorganic thin composite films are also found that their protection effect against permeation of water vapor can be significantly enhanced by choosing their suitable composition ratio and deposition method, in addition, the main factors affecting the permeation of water vapor through the oxide films are found to be the polarizability and the packing density.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.89-98
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• 2005

Preliminary pile load tests for the design of large diameter drilled shaft were performed on two of reduced scale(D=1370mm) test piles. The maximum loads of 2350 tonf in each direction were applied using bi-directional hydraulic jacks(Osterberg Cell) at toe. Neither of the test piles yielded in terms of skin friction and end bearing. Comparisons of the test results with several methods that estimate pile capacity show that the method of Horvath and Kenney(1979) for skin friction and Zhang and Einstein(1998) for end bearing were most appropriate for the site. The test results were directly applied to pile design in case RQD of skin and toe was larger than that of the test pile. It is desirable, therefore, to consider not only unconfined compression strength but also rock mass properties(i.e. TCR, RQD) for skin friction and end bearing evaluation in the future.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.185-190
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• 2011

The purpose of this study is to investigate the influence of organism vigor information solution(OVIS) on the animal cell growth and to set up a condition for cell culture. We investigated the reactions on the MG-63 and MCF-7 cell line in mixture culture media with various amount of REVIEW solution, which is an example among various OVIS. DMEM-HG was used as basic media. The concentration range of the mixture was limited from 0% to 15%. MTT assay is used for cell viability test. The cell was incubated for 14days and the MTT assay was performed on day 1, 3, 7, 10 and 14 throughout the experiment. We used the ELISA reader to measure the Optical Density(O.D) at 595 nm wavelength filter. MCF-7 was linearly proliferated according to culture time and concentrations of OVIS. On the other hand, MG-63 cells were measured the highest O.D value at 12%. The growth rates of both cells cultured in mixed culture media with OVIS are much higher than those in only basic media, DMEMHG, after 14days. It was confirmed that cell cultured at OVIS grows rapidly at certain period although cells showed a negative effect in initial stage.

• Journal of Microbiology and Biotechnology
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• v.32 no.4
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• pp.522-530
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• 2022

In this study we aimed to develop novel ZnO-NP/chitosan/β-glycerophosphate (ZnO-NP/CS/β-GP) antibacterial hydrogels for biomedical applications. According to the mass fraction ratio of ZnO-NPs to chitosan, mixtures of 1, 3, and 5% ZnO-NPs/CS/β-GP were prepared. Using the test-tube inversion method, scanning electron microscopy and Fourier-transform infrared spectroscopy, the influence of ZnO-NPs on gelation time, chemical composition, and cross-sectional microstructures were evaluated. Adding ZnO-NPs significantly improved the hydrogel's antibacterial activity as determined by bacteriostatic zone and colony counting. The hydrogel's bacteriostatic mechanism was investigated using live/dead fluorescent staining and scanning electron microscopy. In addition, crystal violet staining and MTT assay demonstrated that ZnO-NPs/CS/β-GP exhibited good antibacterial activity in inhibiting the formation of biofilms and eradicating existing biofilms. CCK-8 and live/dead cell staining methods revealed that the cell viability of gingival fibroblasts (L929) cocultured with hydrogel in each group was above 90% after 24, 48, and 72 h. These results suggest that ZnO-NPs improve the temperature sensitivity and bacteriostatic performance of chitosan/β-glycerophosphate (CS/β-GP), which could be injected into the periodontal pocket in solution form and quickly transformed into hydrogel adhesion on the gingiva, allowing for a straightforward and convenient procedure. In conclusion, ZnO-NP/CS/β-GP thermosensitive hydrogels could be expected to be utilized as adjuvant drugs for clinical prevention and treatment of peri-implant inflammation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.12
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• pp.1022-1032
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• 2002

A multibit DRAM BIST methodology reducing redundancy programming overhead has been proposed. It is capable of counting and locating faulty bits simultaneously with the test. If DRAM cells are composed of n blocks generally, the proposed BIST can detect the state of no error, the location of faulty bit block if there is one error and the existence of errors in more than two blocks, which are n + 2 states totally, with only n comparators and an 3 state encoder. Based on the proposed BIST methodology, the testing scheme which can detect the number and locations of faulty bits with the errors in two or more blocks, can be easily implemented. Based on performance evaluation, the test and redundancy programming time of 64MEG DRAM with 8 blocks is reduced by 1/750 times with 0.115% circuit overhead.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.846-849
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• 1991

This paper reports the principle, system confiquration, test results of optical voltage sensor using quartz pockels cell. The Pockels effect of quartz material is used for designing optical voltage sensor. The quarts material has very high half-wave voltage, so, it can be applied to measure high voltage level. Experimental results show that the optical voltage sensor has excellent linear characteristics within the applied AC voltage of 1200V.