• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.05a
• /
• pp.26-29
• /
• 2002

The ramp waveform has recently been introduced to erase wall charges of the previously selected cells for plasma display. However. the ramp waveform can't completely remove wall charges. In this paper. we suggested new erase waveform having a complex with close width pulse and ramp pulse for complete erasing. The erasing margin of suggested waveform is wider than the conventional waveform. Moreover. suggested wave form can reduce the erasing time compared.

• Current Applied Physics
• /
• v.18 no.11
• /
• pp.1261-1267
• /
• 2018

In this paper, an off-axis digital holographic microscopy compensated with self-hologram rotation is presented. The process is implemented via subtracting the unwrapped phase maps of the off-axis parabolic hologram and its rotation $180^{\circ}$ to eliminate the tilt induced by the angle between the spherical object wave O and the plane reference wave R. Merit of the proposed method is that it can be done without prior knowledge of physical parameters and hence can reconstruct a parabolic hologram of $1024{\times}768$ pixels within tens of milliseconds since it doesn't require a digital reference wave. The method is applied to characterize rough gold bumps and the obtained results were compared with those extracted from the conventional reconstruction method. The comparison showed that the proposed method can characterize rough surfaces with excellent contrast and in realtime. Merit of the proposed method is that it can be used for monitoring smaller biological cells and micro-fluidic devices.

• IMMUNE NETWORK
• /
• v.13 no.4
• /
• pp.133-140
• /
• 2013

Since the discovery of the immunomodulation property of mesenchymal stem cells (MSCs) about a decade ago, it has been extensively investigated whether MSCs can be used for the treatment of immune-related diseases, such as graft versus-host disease (GvHD). However, how to evaluate the efficacy of human MSCs for the clinical trial is still unclear. We used an MHC-mismatched model of GvHD (B6 into BALB/c). Surprisingly, the administration of the human MSCs (hMSCs) could reduce the GvHD-related mortality of the mouse recipients and xenogeneically inhibit mouse T-cell proliferation and $IFN-{\gamma}$ production in vitro. We recently established a new protocol for the isolation of a homogeneous population of MSCs called subfractionation culturing methods (SCM), and established a library of clonal MSC lines. Therefore, we also investigated whether MSCs isolated by the conventional gradient centrifugation method (GCM) and SCM show different efficacy in vivo. Intriguingly, clonal hMSCs (hcMSCs) isolated by SCM showed better efficacy than hMSCs isolated by GCM. Based on these results, the MHC-mismatched model of GvHD may be useful for evaluating the efficacy of human MSCs before the clinical trial. The results of this study suggest that different MSC lines may show different efficacy in vivo and in vitro.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.6
• /
• pp.1843-1849
• /
• 2004

Conventional medicines have usually sorted to a number of treatments such asoperation, radiotherapy, and chemotherapy. The existing anti-cancer agents, designed to eradicate cancer cells, have strong toxicities, also with leading to harmful side effects. Recently, a number of researches on natural products have been actively carried out in efforts to develop new treatments that can decrease side effects or increase anti-cancer effects. We performed this study to understand the molecular basis underlying the antitumor effects of Pharbitis nil, and Plantago asiatica, which have been used for herbal medicinal treatments against cancers in East Asia. We analyzed the effects of these medicinal herbs on proliferation and on expression of cell growth/apoptosis related molecules, with using an AGS gastric cancer cell line. The treatment of Pharbitis nil dramatically reduced cell viabilities in a dose and time-dependent manner, but Plantago asiatica didn't. FACS analysis and Annexin V staining assay also showed that Pharbitis nil induce apoptotic cell death of AGS. Expression analyses via RT-PCR and Western blots revealed that Pharbitis nil didn't increase expression of the p53 and its downstream effector p21/sup wafl/, and that the both increased expression of apoptosis related Sax and cleavage of active caspase-3 protein. We also confirmed the translocation of Sax to mitochondria. Collectively, our data demonstrate that Pharbitis nilinduce growth inhibition and apoptosis of human gastric cancer cells, and these effects are correlated with down- and up-regulation of growth-regulating apoptotic and tumor suppressor genes, respectively.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.5
• /
• pp.2013-2020
• /
• 2014

Background: The aldehyde dehydrogenase 1 family member A1 (ALDH1A1) is one of the promising markers for identifying cancer stem cells in many cancer types, along with other markers including CD44. The aim of the present study was to evaluate the expression and clinical significance of putative cancer stem cell markers, CD44 and ALDH1A1, in a series of urothelial carcinomas of urinary bladder (UCUB) by tissue microarray (TMA). Materials and Methods: A total of 159 Urothelial Carcinomas (UC) including 96 (60%) low grade and 63 (40%) high grade carcinomas were immunohistochemically examined for the expression of CD44 and ALDH1A1. Correlations of the relative expression of these markers with clinicopathological parameters were also assessed. Results: High level expression of ALDH1A1 was found in 16% (25/159) of bladder UC which was significantly correlated with increased tumor size (p value=0.002), high grade (p value<0.001), pathologic stage (T1, p value=0.007 and T2, p value<0.001) and increased rate of recurrence (p value=0.013). A high level of CD44 expression was found in 43% (68/159) of cases, being positively correlated with histologic grade (p value=0.032) and recurrence (p value=0.039). Conclusions: Taken together, our results showed that ALDH1 was concurrently expressed in a fraction of CD44+ tumors and its expression correlated with poor prognosis in UCs. ALDH1A1 could be an ideal marker for targeted therapy of UCs in combination with conventional therapies, particularly in patients with high grade carcinomas. These findings indicate that cells expressing ALDH1A1 along with CD44 can be a potential therapeutic target in bladder carcinomas.

• Journal of Internet Computing and Services
• /
• v.17 no.6
• /
• pp.25-31
• /
• 2016

Recently, with greatly improving the wireless communication technology, new services are created using smart sensors, i.e., machine-to-machine (M2M) and Internet of Things (IoT). In this paper, we propose a novel IoT device (IoTD) personalization method that adopt Small-cell Access Points (SAPs) to control IoTDs using user equipments (UEs), e.g., smart phones and tablet PC, from service users. First, we introduce a system architecture that consists of UE, IoTD, and SAP and propose the IoTD personalization method with two procedures, i.e., IoTD profile registration procedure and IoTD control procedure. Finally, through simulations, we evaluated the system performance of the proposed scheme and it is shown that the proposed scheme outperforms the conventional scheme in terms of the packet delay, packet loss probability, and normalized throughput.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.1
• /
• pp.3-15
• /
• 2000

As an OLT in the central office controls up to 64 ONUs in the subscriber area via a passive optical splitter, the hU PON system can accomodate PTTx in a single platform with low cost. To operate the system, it is important to implement an efficient MAC protocol, however, the protocol is currently the further study area in the ITU-T 0.983.1. In this paper, we suggest the MAC protocol which is needed to send cells of ONU to upstream, and based on the ITU-T G.983.1. We survey conventional MAC protocols which are not based on G.983.1, and then formulate the minislot period and length for the grant request and determine the optimal value of each parameter. Also, we suggest a coding scheme for the grant field of the PLOAM cell and the procedure allocating optimal parameters to the ONU.

• Journal of Korea Multimedia Society
• /
• v.14 no.5
• /
• pp.614-621
• /
• 2011

This paper presents design of a wide tuning range digitally controlled oscillator(DCO) for Mobile-DTV applications. DCO is the key element of the ADPLL block that generates oscillation frequencies. We proposed a binary delay chain(BDC) structure, for wide tuning range DCO, modifying conventional fixed delay chain. The proposed structure generates oscillation frequencies by delay cell combination which has a variable delay time of $2^i$ in the range of $0{\leq}i{\leq}n-1$. The BOC structure can reduce the number of delay cells because it make possible to select delay cell and resolution. We simulated the proposed DCO by Cadence's Spectre RF tool in 1.8V chartered $0.18{\mu}m$ CMOS process. The simulation results showed 77MHz~2.07GHz frequency range and 3ps resolution. The phase noise yields -101dBc/Hz@1MHz at Mobile-DTV maximum frequency 1675MHz and the power consumption is 5.87mW. The proposed DCO satisfies Mobile-DTV standards such as ATSC-M/H, DVB-H, ISDB-T, T-DMB.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.411.1-411.1
• /
• 2014

This study evaluates the utility of an antibacterial microneedle composed of green tea extract (GT) and hyaluronic acid (HA), for the efficient delivery of GT. These microneedles have the potential to be a patient-friendly method for the conventional sustained release of drugs. In this study, a fabrication method using a mold-based technique to produce GT/HA microneedles with a maximum area of ${\sim}60mm^2$ with antibacterial properties was used to manufacture transdermal drug delivery systems. Fourier transform infrared (FTIR) spectrometry was carried out to observe the potential modifications in the microneedles, when incorporated with GT. The degradation rate of GT in GT/HA microneedles was controlled simply by adjusting the HA composition. The effects of different ratios of GT in the HA microneedles were determined by measuring the release properties. In HA microneedles loaded with 70% GT (GT70), a continuous higher release rate were sustained for 72 h. The in vitro cytotoxicity assays demonstrated that GT/HA microneedles are not generally cytotoxic to chinese hamster ovary cells (CHO-K1), human embryonic kidney cells (293T), and mouse muscle cells (C2C12), which were treated for 12 and 24 h. Antimicrobial activity of the GT/HA microneedles was demonstrated by ~95% growth reduction of gram negative [Escherichia coli (E. coli), Pseudomonas putida (P. putida) and Salmonella typhimurium (S. typhimurium)] and gram positive bacteria [Staphylococcus aureus (S. Aureus) and Bacillus subtilis (B. subtilis)], with GT70. Furthermore, GT/HA microneedles reduced bacterial growth in the infected skin wound sites and improved skin wound healing process in rat model.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.115-116
• /
• 2012

The demand for flexible electronic systems such as wearable computers, E-paper, and flexible displays has increased due to their advantages of excellent portability, conformal contact with curved surfaces, light weight, and human friendly interfaces over present rigid electronic systems. This seminar introduces three recent progresses that can extend the application of high performance flexible inorganic electronics. The first part of this seminar will introduce a RRAM with a one transistor-one memristor (1T-1M) arrays on flexible substrates. Flexible memory is an essential part of electronics for data processing, storage, and radio frequency (RF) communication and thus a key element to realize such flexible electronic systems. Although several emerging memory technologies, including resistive switching memory, have been proposed, the cell-to-cell interference issue has to be overcome for flexible and high performance nonvolatile memory applications. The cell-to-cell interference between neighbouring memory cells occurs due to leakage current paths through adjacent low resistance state cells and induces not only unnecessary power consumption but also a misreading problem, a fatal obstacle in memory operation. To fabricate a fully functional flexible memory and prevent these unwanted effects, we integrated high performance flexible single crystal silicon transistors with an amorphous titanium oxide (a-TiO2) based memristor to control the logic state of memory. The $8{\times}8$ NOR type 1T-1M RRAM demonstrated the first random access memory operation on flexible substrates by controlling each memory unit cell independently. The second part of the seminar will discuss the flexible GaN LED on LCP substrates for implantable biosensor. Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as the future flexible display technology and a type of implantable LED biosensor for a therapy tool. The final part of this seminar will introduce a highly efficient and printable BaTiO3 thin film nanogenerator on plastic substrates. Energy harvesting technologies converting external biomechanical energy sources (such as heart beat, blood flow, muscle stretching and animal movements) into electrical energy is recently a highly demanding issue in the materials science community. Herein, we describe procedure suitable for generating and printing a lead-free microstructured BaTiO3 thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible BaTiO3 thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of BaTiO3 thin film nanogenerator.