• The Korean Journal of Physiology
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• v.24 no.2
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• pp.331-344
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• 1990

What makes glucose transport function sensitive to insulin in one cell type such as adipocyte, and insensitive in another such as liver cells is unresolved question at this time. Recently it is known that insulin stimulates glucose transport in adipocytes largely by redistributing transporter from the storage pool that is included in a low density microsomal fraction to plasma membrane. Therefore, insulin sensitivity may depend upon the relative distribution of gluscose transporters between the plasma membrane and in an intracellular storage compartment. In hepatocytes, the subcellular distribution of glucose transporter is less well documented. It is thus possible that the apparent insensitivity of the hepatocyte system could be either due to lack of the constitutively maintained, intracellular storage pool of glucose transporter or lack of insulin-mediated transporter translocation mechanism in this cell. In this study, I examined if any intracellular glucose transporter pool exists in hepatocytes and this pool is affected by insulin. The results obtained summarized as followings: 1) Distribution of subcellular fractions of hepatocyte showed that there are $24.9{\pm}1.3%$ of plasma membrane, $36.9{\pm}1.7%$ of nucleus-mitochondria enriched fraction, $23.5{\pm}1.2%$ of lysosomal fraction, $9.6{\pm}1.0%$ of high density microsomal fraction and $4.9{\pm}0.5%$ of low density microsomal fraction. 2) In adipocyte, there were $29.9{\pm}2.6%$ of plasma membrane, $19.4{\pm}1.9%$ of nucleus-mitochondria enriched fraction, $26.7{\pm}1.8%$ of high density microsomal fraction and $23.9{\pm}2.1%$ of low density microsomal fraction. 3) Surface labelling of sodium borohydride revealed that plasma membrane contaminated to lysosomal fraction by $26.8{\pm}2.8%$, high density microsomal fraction by $8.3{\pm}1.3%$ and low density microsomal fraction by $1.7{\pm}0.4%$ respectively. 4) Cytochalasin B bound to all of subcellular fractions with a Kd of $1.0{\times}10^{-6}M$. 5) Photolabelling of cytochalasin B to subcellular fractions occurred on 45 K dalton protein band, a putative glucose transporter and D-glucose inhibited the photolabelling. 6) Insulin didn't affect on the distribution of subcellular fractions and translocation of intracellular glucose transporters of hepatocytes. 7) HEGT reconstituted into hepatocytes was largely associated with plasma membrane and very little was found in low density microsomal fraction which equals to the native glucose transporter distribution. Insulin didn't affect on the distribution of exogeneous glucose transporter in hepatocytes. From the above results it is concluded that insulin insensitivity of hepatocyte may due to lack of intracellular storage pool of glucose transporter and thus intracellular storage pool of glucose transporter is an essential feature of the insulin action.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.377-386
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• 2003

In this paper, we present an application layer protocol to support secure wireless Internet services, called Application Layer Security(ALS). The drawbacks of the two traditional approaches to secure wireless applications motivated the development of ALS. One is that in the conventional application-specific security protocol such as Secure HyperText Transfer Protocol(S-HTTP), security mechanism is included in the application itself. This gives a disadvantage that the security services are available only to that particular application. The other is that a separate protocol layer is inserted between the application and transport layers, as in the Secure Sockets Layer(SSL)/Transport Layer Security(TLS). In this case, all channel data are encrypted regardless of the specific application's requirements, resulting in much waste of network resources. To overcome these problems, ALS is proposed to be implemented on top of HTTP so that it is independent of the various transport layer protocols, and provides a common security interface with security applications so that it greatly improves the portability of security applications. In addition, since ALS takes advantages of well-known TLS mechanism, it eliminates the danger of malicious attack and provides applications with various security services such as authentication, confidentiality integrity and digital signature, and partial encryption. We conclude this paper with an example of applying ALS to the solution of end-to-end security in a present commercial wireless protocol stack, Wireless Application Protocol.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.107-108
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• 2006

This paper shows the design optimization of the paper feeding mechanism under dynamic behavior by using commercial codes of RecurDyn/MTT2D and RecurDyn/AutoDesign which are developed by functionBay, Inc. A virtual mockup for dynamics analysis of the paper feeding mechanism is build on RecurDyn/MTT2D and is simulated. Flexible paper is represented as a series of rigid bars connected by revolute joints and rotational spring dampers. Paper is fed by a contact and friction mechanism on rollers or guides. The slip of the paper and nip force of rollers are measured to estimate the system performance. After a simulation, these performances are automatically send to RecurDyn/AutoDesign which is a sequential approximate optimization tool based on the response surface modeling. RecurDyn/AutoDesign makes the approximate objective function and computes the optimized design points of the design variables and gives them to analysis tool. And then the simulation is repeated with the updated design variables. These processes are repeated until finding a tolerable design optimization. In this paper, a paper feeding mechanism is introduced and it is optimized with the proposed algorithms.

• The Korean Journal of Physiology
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• v.27 no.2
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• pp.123-138
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• 1993

The mechanism of insulin action to increase glucose transport is attributed to glucose transporter translocation from intracellular storage pools to the plasma membrane in insulin-sensitive cells. The present study was designed to visualize the redistribution of the glucose transporter by means of an immunogold labelling method. Our data clearly show that glucose transporter molecules were visible by this method. According to the method this distribution of glucose transporters between cell surface and intracellular pool was different in adipocytes. The glucose transporter molecules were randomly distributed at the cell surface whereas the molecules at LDM were farmed as clusters. By insulin treatment the number of homogeneous random particles increased at the cell surface whereas the cluster forms decreased at the intracellular storage pools. It suggests that the active molecules needed to be evenly distributed far effective function and that the inactive molecules in storage pools gathered and termed clusters until being transferred to the plasma membrane.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.501-507
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• 2004

The uniquely large dimensions of Giant radio galaxies (GRGs) make it possible to probe for stringent limits on total energy content, Faraday rotation, Alfven speeds, particle transport and radiation loss times. All of these quantities are more stringently limited or specified for GRG's than in more 'normal' FRII radio sources. I discuss how both global and detailed analyses of GRG's lead to constraints on the CR electron acceleration mechanisms in GRG's and by extension in all FRII radio sources. The properties of GRG's appear to rule out large scale Fermi-type shock acceleration. The plasma parameters in these systems set up conditions that are favorable for magnetic reconnection, or some other very efficient process of conversion of magnetic to particle energy. We conclude that whatever mechanism operates in GRG's is probably the primary extragalactic CR acceleration mechanism in the Universe.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.239-243
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• 2005

Fully three-dimensional Large Eddy Simulation calculations of the flow past 2D cavity are conducted to study the purging of neutrally buoyant or dense miscible contaminants introduced instantaneously inside the cavity. The length to depth ratio(L/D) is 2 and Reynolds number based on the depth is 3,360. Fully developed turbulent inflow are fed at the inlet from precursor simulation of channel flow. Mean flow pattern and unsteady features are investigated based on the experimental data of Pereira and Sousa. From the study of mass exchange processes, it is found that the mechanism of removal of the contaminant is very different between the non-buoyant and buoyant cases. In the buoyant case, internal wave motion which interacts with a strong cavity vortex is dominant in the ejection mechanism of the contaminants.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.862-868
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• 2008

Many studies have been conducted to increase heat transfer in fluid. One of the various heat transfer enhancement techniques is suspending fine metallic or nonmetallic solid powder in traditional fluid. Nanofluid is defined as a new kind of heat transfer fluid containing a very small quantity of nanometer particles that are uniformly and stably suspended in a liquid. This study investigates the effect of nanofluid containing diamond, CuNi and CuAg nanometer particles, and proposes the heat transport mechanism of nanofluid. The test result shows that the thermal conductivity of nanofluid is much higher than that of traditional fluid, and the increasing rate of the conductivity is dependent on the conductivity of the solid metal.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.2
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• pp.195-199
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• 2014

Although the Herba Cirsii is known to posses beneficial health effects, the anti-diabetic effects and the mechanism of action have not been elucidated. In the present study we have shown that Herba Cirsii Extract (HCE) can stimulate glucose uptake in OP9 adipocytes. Unlike insulin, HCE did not stimulate the Ser473 phosphorylation and activation of Akt. The increasing effects of HCE on glucose uptake were inhibited by PD680509 and compound C pretreatment, which means that the glucose uptake effects by HCE were carried out by extracelluar signal-regulated kinase1/2(ERK1/2) and AMP-activated protein kinase (AMPK) activation. Further studies revealed that HCE stimulated glucose transport occurs through a mechanism involving ERK1/2 activation and AMPK activation.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.114-115
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• 2007

As a carrier of malaria and sneak of blood, mosquitoes are regarded as an unpleasant insect. However, there are novel phenomena that happen inside a mosquito. Among them, we focused on the blood sucking function of a female mosquito. The main objective of this study was to investigate the mosquito's pumping mechanism in order to resolve the problem encountered when we inject or transport biologic fluids into a micro-chip. To analyze the pumping mechanism, we visualized the blood sucking process inside a female mosquito. Flow characteristics of blood flow in a proboscis were investigated experimentally using a micro-PIV velocity field measurement technique. The anatomical variation of head, thorax, abdomen which work as pumps and valves, was visualized using the syncrotron X-ray micro-imaging technique.

• Journal of Pharmaceutical Investigation
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• v.19 no.1
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• pp.39-46
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• 1989

The clonidine transport mechanism through the skin was investigated with assumptions that epidermis is heterogeneous and two-layer membrane. Immobilization of clonidine was not found in stratum corneum but in viable epidermis. The sorption in the viable epidermis agreed with the dual sorption theory. Diffusion coefficient in stratum corneum was five order magnitude less than that in viable epidermis. In viable epidermis, the ratio of true diffusivity to apparent diffusivity increased initially then decreased as a function of clonidine concentration, and the true diffusivity was always larger than the apparent diffusivity.