• Asian-Australasian Journal of Animal Sciences
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• v.30 no.6
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• pp.886-892
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• 2017

Objective: Transgenic technology is widely used for industrial applications and basic research. Systems that allow for genetic modification play a crucial role in biotechnology for a number of purposes, including the functional analysis of specific genes and the production of exogenous proteins. In this study, we examined and verified the cumate-inducible transgene expression system in chicken DF1 and quail QM7 cells, as well as loxP element-mediated transgene recombination using Cre recombinase in DF1 cells. Methods: After stable transfer of the transgene with piggyBac transposon and transposase, transgene expression was induced by an appropriate concentration of cumate. Additionally, we showed that the transgene can be replaced with additional transgenes by co-transfection with the Cre recombinase expression vector. Results: In the cumate-GFP DF1 and QM7 cells, green fluorescent protein (GFP) expression was repressed in the off state in the absence of cumate, and the GFP transgene expression was successfully induced in the presence of cumate. In the cumate-MyoD DF1 cells, MyoD transgene expression was induced by cumate, and the genes controlled by MyoD were upregulated according to the number of days in culture. Additionally, for the translocation experiments, a stable enhanced green fluorescent protein (eGFP)-expressing DF1 cell line transfected with the loxP66-eGFP-loxP71 vector was established, and DsRed-positive and eGFP-negative cells were observed after 14 days of co-transfection with the DsRed transgene and Cre recombinase indicating that the eGFP transgene was excised, and the DsRed transgene was replaced by Cre recombination. Conclusion: Transgene induction or replacement cassette systems in avian cells can be applied in functional genomics studies of specific genes and adapted further for efficient generation of transgenic poultry to modulate target gene expression.

• Journal of Korean Library and Information Science Society
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• v.44 no.1
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• pp.27-47
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• 2013

This study investigated the classification performance of a kNN classifier using the feature selection methods based on document frequency(DF) and collection frequency(CF). The results of the experiments, which used HKIB-20000 data, were as follows. First, the feature selection methods that used high-frequency terms and removed low-frequency terms by the CF criterion achieved better classification performance than those using the DF criterion. Second, neither DF nor CF methods performed well when low-frequency terms were selected first in the feature selection process. Last, combining CF and DF criteria did not result in better classification performance than using the single feature selection criterion of DF or CF.

• Journal of Communications and Networks
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• v.12 no.1
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• pp.67-73
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• 2010

Current on-demand ad-hoc routing protocols are not appropriate for wireless mesh networks (WMNs), because flooding-based route discovery is both redundant and expensive in terms of control message overhead. In this paper, we propose an efficient on-demand routing approach with directional flooding (DF), which is suitable for the WMNs with limited mobility. In the route discovery process to reach a gateway, our DF scheme can reduce the number of route request (RREQ) packets broadcast by using a restricted directional flooding technique. Simulation results show that ad hoc on-demand distance vector (AODV) with DF (AODV-DF) can significantly reduce routing overhead by RREQ packets and enhance overall performance compared with the original AODV.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.1-6
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• 2014

In many medical image devices, dc noise often prevents normal diagnosis. In wireless capsule endoscopy systems, multipath fading through indoor wireless links induces inter-symbol interference (ISI) and indoor electric devices generate impulsive noise in the received signal. Moreover, dc noise, ISI, and impulsive noise are also found in optical fiber communication that can be used in remote medical diagnosis. In this paper, a blind signal processing method based on the biased probability density functions of constant modulus error that is robust to those problems that can cause error propagation in decision feedback (DF) methods is presented. Based on this property of robustness to error propagation, a DF version of the method is proposed. In the simulation for the impulse response of optical fiber channels having slowly varying dc noise and impulsive noise, the proposed DF method yields a performance enhancement of approximately 10 dB in mean squared error over its linear counterpart.

• Proceedings of the KSAR Conference
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• 2001.10a
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• pp.3-4
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• 2001

Normal cells proliferate generally a limited number doublings in culture and only rarely have they been shown to overcome cellular senescence and crisis stages, and immortalize spontaneously. I have established a number of non-chemically and non-chemically immortalized embryo fibroblastic (EF) cell lines in continuous cell culture. These include the spontaneously immortalized cell line, DF-1 and several immortal EF cell lines derived from various embryonic tissues. I have previously demonstrated that all of the immortal EF cells established have rapid cell proliferation capacity compared to primary EF cells, presumably due to the deregulation of cell cycle regulators such as p53, E2F-1 and the numerous cyclins. DF-1 cells, in particular, were shown to proliferate more rapidly under normal culture conditions compared to other immortal EF cells, implicating other mechanisms may be important for regulating their growth. The possible mechanism(s) underlying the accelerated growth of DF-1 cells will be addressed in this study. (omitted)

• Journal of Periodontal and Implant Science
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• v.50 no.4
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• pp.268-277
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• 2020

Purpose: Many home care treatments can be used to promote the health and longevity of dental implants; however, few studies are available to support the concept that self-performed oral hygiene behaviors are an essential tool for improving and maintaining oral health. We investigated age-stratified associations between dental health behaviors related to tooth brushing (TB) and oral hygiene product use in Korean adults with implants. Methods: A total of 1,911 subjects over 19 years of age who had 1 or more implants and who participated in the 2013 to 2015 Korea National Health and Nutrition Examination Survey were reviewed. Periodontal status was assessed using Community Periodontal Index (CPI) scores, and periodontitis was defined as a CPI greater than or equal to 3. The complex sampling design of the survey was utilized to obtain the variance and individual weight of each analyzed factor. A high CPI was the outcome variable, and the main explanatory variables were oral hygiene behaviors, such as TB, dental floss (DF), interproximal brushing, and mouth rinsing. Results: Almost all individuals with a lower CPI brushed their teeth twice or more per day, in contrast to those with a higher CPI, and were likely to use DF. The adjusted odds ratio of not using DF for a higher CPI was 1.83 (95% confidence interval, 1.35-2.49). Conclusions: TB was implemented more than twice a day by patients with good oral health, and the combination of TB and DF significantly reduced the prevalence of a higher CPI. Self-performed oral hygiene practices combining TB and DF were significantly related to a low prevalence of periodontitis in implant patients.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1042-1047
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• 1998

The fluorescence excitation (FE) spectrum of the S1-S0 (1B2-1A1) transition of dimethyldiazirine cooled in supersonic jet expansions has been obtained. Dispersed fluorescence (DF) spectra have also been taken for some prominent features of the FE spectrum. Vibrational analyses of the FE and DF spectra with the help of an ab initio molecular orbital calculation lead to some new vibrational assignments and refined fundamental frequencies.

• The Korean Journal of Rehabilitation Nursing
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• v.8 no.1
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• pp.38-49
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• 2005

Purpose: The purpose of this study was to examine the cognitive function in NIDDM patients. Method: The data were collected at MI OPD in C University hospital. with Digit Span Forward & Backward, Trail Making Test-A, Trail Making Test-B, and MMSE. Result: There were significant differences in DF, DB, TMT-A, and TMT-B according to gender, and in TMT-A according to living with spouse and comorbidity. There were significant differences in DF, DB, TMT-A, TMT-B, and MMSE according to monthly income, and in DF, TMT-A, and TMT-B according to hypertensive state. But, there was no difference in cognitive function score according to diabetes-related complication and diabetes treatment modality. There was a significant positive correlation between duration of NIDDM and TMT-A(r=.215, p=.025). The global cognition score was explained 42.1% of varient by age, duration of education, monthly income, and hypertensive state. Conclusion: As above results showed, among age, duration of education, monthly income, and hypertensive state, prevented and managed hypertensive state which is modifiable factor may reduce or delay cognitive function impairment in NIDDM patients. And DF & DB, TMT-A & B could be more utilized as useful cognitive function measurements because those tests reflected cognitive function in NIDDM patients better than MMSE.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.102-122
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• 2017

Nanotechnology has provided a set of tools that the engineers can use to design and manufacture integrated nano devices, which are capable of performing sensing, computing, data storing and actuation. One of the main hurdles for nano devices has been the amount of power that it can generate for transmission of data. In this paper, we proposed cooperative nano communication in the Terahertz (THz) Gap frequency band to increase the range of transmission. Outage probability (OP) performances for the proposed cooperative nano communication networks in the THz band (0.1 - 10THz) have been evaluated for the following scenarios; A) A single decode-and-forward (DF) relay over independent identically distributed (i.i.d.) Rayleigh fading channels, B) DF multi-relay network with best relay selection (BRS) over i.i.d. Rayleigh fading channels, and C) DF multi-relay network with multiple hops with BRS over i.i.d. Rayleigh fading channels. The results show that the transmission distance can be improved significantly by employing DF relays. Also, it is shown that by increasing the number of hops in a relay the OP performance is marginally degraded. The analytical results have been verified by Monte-Carlo simulation.

• Natural Product Sciences
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• v.23 no.1
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• pp.9-15
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• 2017

DF formula is comprised of three traditional herbs, Ephedra intermedia, Rheum palmatum and Lithospermum erythrorhizon, and locally used for treating of the metabolic diseases, such as obesity and diabetes in Korea. We tried to optimize the extraction conditions of two major components, (-)-ephedrine and (+)-pseudoephedrine, in DF formula using response surface methodology with Box-Behnken design (BBD). The experimental conditions with 70% for EtOH concentrations, 4.8 hour for extraction hours and 8.7 times for the solvent to material ratio were suggested for the optimized extraction of DF formula with the highest amounts of (-)-ephedrine and (+)-pseudoephedrine in the designed model.