Miniaturised dual-band implantable antenna for wireless biotelemetry

Cho, Y.,Yoo, H. IET 2016 Electronics letters Vol.52 No.12

<P>A miniaturised implantable antenna with dual-band operation the Medical Implant Communications Service (MICS) (402-405 MHz) and Industrial, Scientific, and Medical (ISM) (2400.0-2483.5 MHz) bands is presented. The size of the proposed antenna is 31.5 mm(3) (8.75 mm x 7.2 mm x 0.5 mm) which is the smallest size compared to previous implantable antennas. A serpentine-shaped radiating patch and open-end slot placed on the ground plane are used for miniaturisation. The performance of the antenna was evaluated from measurements and is based on good agreement with simulations.</P>

Adaptive live streaming system performance of MMT and DASH over a deployed LTE network

Cho, Y.,Park, S.,Kim, K.,Suh, D.Y. IET 2016 Electronics letters Vol.52 No.13

<P>Moving Picture Expert Group (MPEG) media transport and dynamic adaptive streaming over Hypertext Transfer Protocol are compared, which have been standardised by the MPEG for internet-based video services. Their performances as adaptive live streaming systems are evaluated over a deployed long term evolution network. The results provide their operational limitations and optimal operation parameters to improve resource usage and the quality of the users' experience.</P>

Stabilization of 4-manifolds

SpringerScience and Business Media 2014 Science China. Mathematics Vol.57 No.9

Energy concentration of the focusing energy-critical fNLS

Cho, Y.,Hwang, G.,Shim, Y.S. Academic Press 2016 Journal of mathematical analysis and applications Vol.437 No.1

<P>We consider the fractional nonlinear Schrodinger equation (fNLS) with non-local dispersion vertical bar del vertical bar(alpha) and focusing energy-critical Hartree type nonlinearity [-(vertical bar x vertical bar(-2 alpha) * vertical bar u vertical bar(2))u]. We consider the energy -concentration phenomena of radial blowup solutions near the maximal existence time. We use the concentration -compactness approach of [19] for confined case and kinetic energy trapping approach of [21] for unconfined case. (C) 2015 Elsevier Inc. All rights reserved.</P>

Phosphorylation-Driven Assembly of the RIP1-RIP3 Complex Regulates Programmed Necrosis and Virus-Induced Inflammation

Cho, Y.,Challa, S.,Moquin, D.,Genga, R.,Ray, T.D.,Guildford, M.,Chan, F.K.M. Cell Press ; MIT Press 2009 Cell Vol.137 No.6

Programmed necrosis is a form of caspase-independent cell death whose molecular regulation is poorly understood. The kinase RIP1 is crucial for programmed necrosis, but also mediates activation of the prosurvival transcription factor NF-κB. We postulated that additional molecules are required to specifically activate programmed necrosis. Using a RNA interference screen, we identified the kinase RIP3 as a crucial activator for programmed necrosis induced by TNF and during virus infection. RIP3 regulates necrosis-specific RIP1 phosphorylation. The phosphorylation of RIP1 and RIP3 stabilizes their association within the pronecrotic complex, activates the pronecrotic kinase activity, and triggers downstream reactive oxygen species production. The pronecrotic RIP1-RIP3 complex is induced during vaccinia virus infection. Consequently, RIP3<SUP>-/-</SUP> mice exhibited severely impaired virus-induced tissue necrosis, inflammation, and control of viral replication. Our findings suggest that RIP3 controls programmed necrosis by initiating the pronecrotic kinase cascade, and that this is necessary for the inflammatory response against virus infections.

Direct Gingival Fibroblast/Osteoblast Transdifferentiation via Epigenetics

Cho, Y.,Kim, B.,Bae, H.,Kim, W.,Baek, J.,Woo, K.,Lee, G.,Seol, Y.,Lee, Y.,Ku, Y. Journal of Dental Research, Inc 2017 Journal of dental research Vol.96 No.5

<P>Alveolar bone resorption caused by trauma or periodontal diseases has represented a challenge for both dental clinicians and researchers. In this study, we evaluate the osteogenic potential of human gingival fibroblasts (HGFs) through a direct transdifferentiation from HGFs to functional osteoblasts via epigenetic modification and osteogenic signaling with bone morphogenetic protein 2 (BMP2) in vitro and in vivo. HGF treatment with 5-aza-2'-deoxycytidine (5-aza-dC) induced demethylation in the hypermethylated CpG islands of the osteogenic lineage marker genes RUNX2 and ALP, and subsequent BMP2 treatment successfully drove the fibroblasts to the osteoblasts' lineage. Cell morphological changes viewed under microscopy and alkaline phosphatase (ALP) and alizarin red S (ARS) staining confirmed the osteoblastic change mediated by epigenetic modification as did real-time polymerase chain reaction (PCR), methylation-specific PCR (MSP), and chromatin immunoprecipitation (ChIP) assay, which demonstrated the altered methylation patterns in the RUNX2 and ALP promoter regions and their effect on gene expression. Furthermore, micro-computed tomography (CT) analysis of in vivo mouse cell transplantation experiments showed high-density signal in the epigenetically modified HGF group; in addition, a significant amount of bone formation was observed in the transplanted material using hematoxylin and eosin (H&E) staining as well. Collectively, our results indicate that epigenetic modification permits the direct programming of HGFs into functional osteoblasts, suggesting that this approach might open a novel therapeutic avenue in alveolar bone regeneration.</P>

Analysis of dose-response to hexanal-induced gene expression in A549 human alveolar cells

Cho, Y.,Song, M. K.,Choi, H. S.,Ryu, J. C. Korean BioChip Society 2014 BioChip Journal Vol.8 No.2

The problems of analyzing dose effects on gene expression are gaining attention in toxicological research. Determining how gene expression profiles change with toxicant dose will improve the utility of arrays in identifying biomarkers and elucidating their modes of toxic action. In the present study, we focused on determining the dose-dependent alterations of gene expression profiles with hexanal exposure and we identified the possible biomarkers of hexanal in A549 human alveolar cells. A549 cells were exposed to a 5% inhibitory concentration (IC5) and a 20% inhibitory concentration (IC20) of hexanal for 48 h. Through microarray analysis using an oligonucleotide chip, we identified that the gene expression patterns were differentially shown in the control group and the hexanal-exposed groups. The hexanal-exposed groups are more sensitive to gene alteration than the control group, and gene expressions are more significantly altered in the IC20 exposure group than in the IC5 exposure group. With clustering analysis of gene expression profiles, we identified 2,929 IC5- and 3,678 IC20-specific genes, and 302 dose-dependently expressed genes. Gene ontology (GO) analysis with 246 annotated genes of the 302 dose-dependent expressed genes showed correlation with the key biological processes involved in neurological system processes, immune system development, cell activation, and cell-cell signaling. In conclusion, current study describes alterations in gene expression profiles in response to exposure to different doses of hexanal and related toxic pathways induced by significantly expressed genes. Moreover, novel genes and pathways that could potentially play a role in the prevention of respiratory disease due to aldehydes are identified.

Spectral evidence for multi-pathway contribution to the upconversion pathway in NaYF4:Yb3+,Er3+ phosphors

Cho, Y.,Song, S.,Lim, S.,Kim, J.,Park, C.,Kim, H. Royal Society of Chemistry 2017 Physical chemistry chemical physics Vol.19 No.10

<P>Although upconversion phosphors have been widely used in nanomedicine, laser engineering, bioimaging, and solar cell technology, the upconversion luminescence mechanism of the phosphors has been fiercely debated. A comprehensive understanding of upconversion photophysics has been significantly impeded because the number of photons incorporated in the process in different competitive pathways could not be resolved. Few convincing results to estimate the contribution of each of the two-, three-, and four-photon channels of near-infrared (NIR) energy have been reported in yielding upconverted visible luminescence. In this study, we present the energy upconversion process occurring in NaYF4: Yb3+, Er3+ phosphors as a function of excitation frequency and power density. We investigated the upconversion mechanism of lanthanide phosphors by comparing UV/VIS one-photon excitation spectra and NIR multi-photon spectra. A detailed analysis of minor transitions in one-photon spectra and luminescence decay enables us to assign electronic origins of individual bands in multi-photon upconversion luminescence and provides characteristic transitions representing the corresponding upconversion channel. Furthermore, we estimated the quantitative contribution of multiple channels with respect to irradiation power and excitation energy.</P>

Physico-chemical properties between organic and conventional kiwifruit orchards in Korea

Cho, Y.,Kim, B.,Cho, H.,Jeong, B. Korean Association of Organic Agriculture 2011 韓國有機農業學會誌 Vol.19 No.S

Organic kiwifruit orchard soils were compared with conventional ones in Korea. Soil structure of organic soil had higher gaseous and liquous phase as well as soil porosity in the surface soil. Although the nutritional level of each orchards were quite different among soils, the analysis of both system revealed that organic kiwifruit orchard soil had similar or even higher nutrient level (N and organic matter content in surface soil) compared to conventional ones. The organic matter content of deep soil also had the high tendency in deep soil of organic soil. Higher level of nitrogen in organic surface soil is presumably due to the excessive application of organic compost and liquid fertilizer rather than the contribution by grasses such as green manure. Available phosphorous level of organic system was quite high but similar in surface soil of both system, compared to the recommended level. Potassium, calcium and magnesium levels were also enough in organic kiwifruit orchard soils.

Supercritical fluid chromatography coupled with in-source atmospheric pressure ionization hydrogen/deuterium exchange mass spectrometry for compound speciation

Cho, Y.,Choi, M.H.,Kim, B.,Kim, S. Elsevier 2016 Journal of chromatography A Vol.1444 No.-

<P>An experimental setup for the speciation of compounds by hydrogen/deuterium exchange (HDX) with atmospheric pressure ionization while performing chromatographic separation is presented. The proposed experimental setup combines the high performance supercritical fluid chromatography (SFC) system that can be readily used as an inlet for mass spectrometry (MS) and atmospheric pressure photo ionization (APPI) or atmospheric pressure chemical ionization (APCI) HDX. This combination overcomes the limitation of an approach using conventional liquid chromatography (LC) by minimizing the amount of deuterium solvents used for separation. In the SFC separation, supercritical CO2 was used as a major component of the mobile phase, and methanol was used as a minor co-solvent. By using deuterated methanol (CH3OD), AP HDX was achieved during SFC separation. To prove the concept, thirty one nitrogen- and/or oxygen-containing standard compounds were analyzed by SFC-AP HDX MS. The compounds were successfully speciated from the obtained SFC-MS spectra. The exchange ions were observed with as low as 1% of CH3OD in the mobile phase, and separation could be performed within approximately 20 min using approximately 0.24 mL of CH3OD. The results showed that SFC separation and APPI/APCI HDX could be successfully performed using the suggested method. (C) 2016 Elsevier B.V. All rights reserved.</P>