• BMB Reports
• /
• v.38 no.3
• /
• pp.314-319
• /
• 2005

Adenosine, as a ubiquitous metabolite, mediates many physiological functions via activation of plasma membrane receptors. Mechanisms of most of its physiological roles have been studied extensively, but research on adenosine-induced apoptosis (AIA) has only started recently. In this study we demonstrate that adenosine dose-dependently triggered apoptosis of cultured baby hamster kidney (BHK) cells. Adenosine-induced apoptotic cell death was characterized by DNA laddering, changes in nuclear chromatin morphology and phosphatidylserine staining. Apoptosis was also quantified by flow cytometry. Results suggest the involvement of adenosine $A_1$ and $A_3$ receptors as well as equilibrative nucleoside transporters in apoptosis induced by adenosine. These results indicate a receptor-transporter co-signaling mechanism in AIA in BHK cells. The involvement of $A_1$ and $A_3$ receptors also implies a possible apoptotic pathway mediated by G protein-coupled receptors.

• BMB Reports
• /
• v.50 no.5
• /
• pp.237-246
• /
• 2017

Synapse is the basic structural and functional component for neural communication in the brain. The presynaptic terminal is the structural and functionally essential area that initiates communication and maintains the continuous functional neural information flow. It contains synaptic vesicles (SV) filled with neurotransmitters, an active zone for release, and numerous proteins for SV fusion and retrieval. The structural and functional synaptic plasticity is a representative characteristic; however, it is highly vulnerable to various pathological conditions. In fact, synaptic alteration is thought to be central to neural disease processes. In particular, the alteration of the structural and functional phenotype of the presynaptic terminal is a highly significant evidence for neural diseases. In this review, we specifically describe structural and functional alteration of nerve terminals in several neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD).

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.501-506
• /
• 1998

A mathematical model is developed to describe the relationship between the manipulated variables (e.g. jacket inlet temperature and feed flow rate) and the important qualities (e.g conversion and weight average molecular weight (Mw)) in a continuous polymerization reactor. The subspace-based identification method for Wiener model is used to retrieve from the discrete sample data the accurate information about both the structure and initial parameter estimates for iterative parameter optimization methods. The comparison of the output of the identified Wiener model with the outputs of a non-linear plant model shows a fairly satisfactory degree of accordance.

• 제어로봇시스템학회:학술대회논문집
• /
• 1998.10a
• /
• pp.468-473
• /
• 1998

A mathematical model was developed for a continuous re-actor in which free radical polymerization of methyl methacrylate (MMA) occurred. Elementary reactions considered in this study were initiation, propagation, termination, and chain transfers to monomer and solvent. The reactor model took into account the density change of the reactor contents and the gel effect. A control system was designed for a continuous reactor using extended Kalman filter (EKF) based non-linear model predictive controller (NLMPC) to control the conversion and the weight average molecular weight of the polymer product. Control input variables were the jacket inlet temperature and the feed flow rate. For the purpose of validation of the control strategy, on-line digital control experiments were conducted with densitometer and viscometer for the measurement of the polymer properties. Despite the com-plex and nonlinear features of the polymerization reaction system, the EKF based NLMPC performed quite satisfactorily for the property control of the continuous polymerization reactor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.05a
• /
• pp.138-140
• /
• 1994

Plasma polymerized thin film was prepared using an interelectrod inductively coupled gas-flow-type reactor. Styrene was chosen as the monomer to be used. This thin films were also delineated by the electron-beam apparatus with an acceleration voltage 30kV, and the pattern in the resist was developed with RIE 80 with argon gas mixture ratio, pressure and RF power. The effect of charge of discharge power on growth rate and etching rate of the thin films were studied. The molecular structure of thin films were investigated by FIR and then was discussed in relation to its quality as a resist. In the case of Plasma polymerization, thickness of resist could be controlled by discharge duration and power. Also etch rate is increased as to growing argon gas and RF power with RIE 80.

• Proceedings of the KIEE Conference
• /
• 1994.11a
• /
• pp.278-280
• /
• 1994

The purpose of this paper is to describe an application of plasma polymerized thin film as an electron beam resist. Plasma polymerized thin film was prepared using an interelectrod inductively coupled gas-flow-type reactor. Styrene was chosen as the monomer to be used. This thin films were also delineated by the electron-beam apparatus and the pattern in the resist was developed with RIE and plasma polymerized apparatus. The effect of charge of pressure on growth rate and etching rate of the thin films were studied. The molecular structure of thin film was investigated by FT-IR and then was discussed in relation to its quality as a resist.

• Journal of the Korean Vacuum Society
• /
• v.9 no.1
• /
• pp.1-6
• /
• 2000

An unexpected error is produced in calculating the transmission probability of a multipartite duct because of beam and shadow effects, if using a simple summation rule like the Oatley's equation. Particles moving in a tube are directed more or less towards the axis of the tube by the beam effect, and the length of a compound tube shortens virtually by the shadow effect originated from a reduction in the number of particles reaching the corner between two tubes of different cross-sections. Both effects make the transmission probability of the tube connected behind and consequently of the whole duct increase slightly. In this paper sources of the error in the calculation of the transmission probability are analyzed quantitatively and variations in the error depending on the dimensions of cylindrical tubes are calculated.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.374-374
• /
• 2010

Charge transfer mechanism of poly(4,4'-aminotriphenylene hexafluoroisopropylidenediphthalimide) (TP6F PI) which exhibits bistable ON and OFF switching has been studied using photoemission electron spectroscopy (PES) and near-edge x-ray absorption fine structure (NEXAFS). Here, we demonstrate novel set-up in which holes are injected by photoemission process instead of direct charge carrier injection via metal electrode. The accumulated charges on the PI surface in the OFF state abruptly flow across the PI film when the bias voltage of a back electrode reaches a specific value, indicating that the film is changed to the ON state. Core level and x-ray absorption spectra probed at charge injection region via photoemission process do not show any evidences implying structural modification of TP6F PI during the phase change. Whereas, in valence band spectra, the highest occupied molecular orbital (HOMO) is shifted toward Fermi level, responsible for improved hole-mobility of TP6F PI of ON state.

• Bulletin of the Korean Chemical Society
• /
• v.2 no.4
• /
• pp.129-132
• /
• 1981

Polystyrene was degraded by using a vibrating ball mill. The viscosities and molecular weights of the degraded products were measured, and the decrease of viscosity $[\eta}$ with ${\dot{s}}$ (rate of shear) observed for the degraded products were analyzed by applying the Ree-Eyring equation for viscous flow. The variation of the parameters $x_2$/{\alhpa}_2,{\beta}_2$ and $x_1{\beta}_1/{\alpha}_1$ in the equation were explained by the fracture of polymer molecules by mechanical force. The electron paramagnetic resonance spectrum of the degraded sample was taken, and it was confirmed that free radicals were produced by the chain-scission of polystyrene.

• The Korean Journal of Food And Nutrition
• /
• v.35 no.3
• /
• pp.178-184
• /
• 2022

The objective of the present study was to investigate the molecular mechanisms involved in the activity of [10]-gingerol using A2058 human melanoma cells. [10]-Gingerol inhibited the proliferation of A2058 cells by 50% at a concentration of 52 μM. Such inhibition was dose-dependent accompanied by morphological change indicative of apoptosis. Furthermore, flow cytometric analysis by Annexin V and PI double staining showed that [10]-gingerol increased the extent of apoptosis. Analysis of the mechanism of these events indicated that [10]-gingerol increased the ratio of Bax to Bcl-2, resulting in the activation of caspase-9, caspase-3, and poly-ADP-ribose polymerase in a dose-dependent manner.