• Title/Summary/Keyword: POSTECH

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Phospholipase C-γ Activation by Direct Interaction with β-Tubulin Isotypes (베타 튜불린에 의한 포스포리파제 C-감마1의 활성화)

  • Lee, In-Bum;Kim, Sung-Kuk;Choi, Jang-Hyun;Suh, Pann-Ghill;Chang, Jong-Soo
    • Journal of Life Science
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    • v.16 no.4
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    • pp.612-617
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    • 2006
  • Phosphoinositide-specific phospholipase $C-{\gamma}\;1\; (PLC-{\gamma}\;1)$ has pivotal roles in cellular signaling by producing second messengers, inositol 1,4,5-trisphosphate $(IP_3)$ and diacylglycerol (DG). Tubulin is a main component of microtubules and mitotic spindle fibers, which are composed of ${\alpha}-$ and ${\beta}-tubulin$ heterodimers in all eukaryotic cells. In humans, six ${\beta}-tubulin$ isotypes have been identified which display a distinct pattern of tissue expression. Previously we found that $PLC-{\gamma}\;1$ and one of four ${\beta}-tubulin$ isotypes including ${\beta}1$, ${\beta}2$, ${\beta}3$ and ${\beta}6$, colocalized in COS-7 cells and cotranslocated to the plasma membrane to activate $PLC-{\gamma}\;1$ upon agonist stimulation. In the present study, we demonstrate that the remaining two, tubulin ${\beta}4$ and ${\beta}5$, also showed a potential to activate $PLC-{\gamma}\;1$. The phosphatidylinositol 4,5-bisphosphate $(PIP_2)$ hydrolyzing activity of $PLC-{\gamma}\;1$ was substantially increased in the presence of purified ${\beta}4$ and ${\beta}5$ tubulin in vitro, whereas the activity was not promoted by bovine serum albumin, suggesting that tubulin ${\beta}4$ and ${\beta}5$ also activate $PLC-{\gamma}\;1$. Taken together, our results suggest that all the ${\beta}-tubulin$ isotype activates $PLC-{\gamma}\;1$ activity to regulate cellular signaling.

An Integrated VR Platform for 3D and Image based Models: A Step toward Interactivity with Photo Realism (상호작용 및 사실감을 위한 3D/IBR 기반의 통합 VR환경)

  • Yoon, Jayoung;Kim, Gerard Jounghyun
    • Journal of the Korea Computer Graphics Society
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    • v.6 no.4
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    • pp.1-7
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    • 2000
  • Traditionally, three dimension model s have been used for building virtual worlds, and a data structure called the "scene graph" is often employed to organize these 3D objects in the virtual space. On the other hand, image-based rendering has recently been suggested as a probable alternative VR platform for its photo-realism, however, due to limited interactivity. it has only been used for simple navigation systems. To combine the merits of these two approaches to object/scene representations, this paper proposes for a scene graph structure in which both 3D models and various image-based scenes/objects can be defined. traversed, and rendered together. In fact, as suggested by Shade et al. [1]. these different representations can be used as different LOD's for a given object. For in stance, an object might be rendered using a 3D model at close range, a billboard at an intermediate range. and as part of an environment map at far range. The ultimate objective of this mixed platform is to breath more interactivity into the image based rendered VE's by employing 3D models as well. There are several technical challenges in devising such a platform : designing scene graph nodes for various types of image based techniques, establishing criteria for LOD/representation selection. handling their transition s. implementing appropriate interaction schemes. and correctly rendering the overall scene. Currently, we have extended the scene graph structure of the Sense8's WorldToolKit. to accommodate new node types for environment maps. billboards, moving textures and sprites, "Tour-into-the-Picture" structure, and view interpolated objects. As for choosing the right LOD level, the usual viewing distance and image space criteria are used, however, the switching between the image and 3D model occurs at a distance from the user where the user starts to perceive the object's internal depth. Also. during interaction, regardless of the viewing distance. a 3D representation would be used, if it exists. Finally. we carried out experiments to verify the theoretical derivation of the switching rule and obtained positive results.

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Ursolic Acid-Induced Elevation of Serum Irisin Augments Muscle Strength During Resistance Training in Men

  • Bang, Hyun Seok;Seo, Dae Yun;Chung, Yong Min;Oh, Kyoung-Mo;Park, Jung Jun;Arturo, Figueroa;Jeong, Seung-Hun;Kim, Nari;Han, Jin
    • The Korean Journal of Physiology and Pharmacology
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    • v.18 no.5
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    • pp.441-446
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    • 2014
  • Ursolic acid (UA), a type of pentacyclic triterpenoid carboxylic acid purified from natural plants, can promote skeletal muscle development. We measured the effect of resistance training (RT) with/without UA on skeletal muscle development and related factors in men. Sixteen healthy male participants (age, $29.37{\pm}5.14$ years; body mass index=$27.13{\pm}2.16kg/m^2$) were randomly assigned to RT (n=7) or RT with UA (RT+UA, n=9) groups. Both groups completed 8 weeks of intervention consisting of 5 sets of 26 exercises, with 10~15 repetitions at 60~80% of 1 repetition maximum and a 60~90-s rest interval between sets, performed 6 times/week. UA or placebo was orally ingested as 1 capsule 3 times/day for 8 weeks. The following factors were measured pre-and post-intervention: body composition, insulin, insulin-like growth factor-1 (IGF-1), irisin, and skeletal muscle strength. Body fat percentage was significantly decreased (p<0.001) in the RT+UA group, despite body weight, body mass index, lean body mass, glucose, and insulin levels remaining unchanged. IGF-1 and irisin were significantly increased compared with baseline levels in the RT+UA group (p<0.05). Maximal right and left extension (p<0.01), right flexion (p<0.05), and left flexion (p<0.001) were significantly increased compared with baseline levels in the RT+UA group. These findings suggest that UA-induced elevation of serum irisin may be useful as an agent for the enhancement of skeletal muscle strength during RT.

Highly Reliability Network Technology for Transmitting a Disaster Information (재해정보 전송을 위한 고신뢰성 네트워크 기술)

  • Kim, Kyung-Jun;Kim, Dongju;Jang, Dae-Jin;Oh, Eun-Ho;Kim, Jin-Man
    • Journal of the Korea Society of Computer and Information
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    • v.20 no.3
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    • pp.115-124
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    • 2015
  • In this paper we analyse the previous (Quality of Services) and QoE(Quality of Experience) methods, and propose a high reliable network system framework and its service forwarding method that is able to provide seamless N-Screen services for proliferating disaster informations. The service satisfaction measurement, i.e., QoE, of contents consumers in N-screens services is going to be important the factor in disaster information proliferation because N-Screen services in the previous methods based on multi devices only focused on information transmission. The proposed system around these services is composed of a disaster information process framework for accepting user's service requirement, push service modules for minimizing the number of packets to be caused when carrying out the push service, and a push service controller for maximizing QoE measures. In order to provide a seamless N-Screen service on diverse screens, such as smartphone, PC, and big screen, we also have Open API(Application Programming Interface) functions. Through these results, we expect to evaluate QoS and QoE quality in the seamless N-Screen service.

Application of Porous Carbon Catalyst Activating Reaction of Positive Electrode in Vanadium Redox Flow Battery (바나듐 레독스 흐름전지의 양극반응 활성화를 위한 다공성 탄소 촉매의 적용)

  • Jeong, Sanghyun;Chun, Seung-Kyu;Lee, Jinwoo;Kwon, Yongchai
    • Journal of Energy Engineering
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    • v.23 no.3
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    • pp.150-156
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    • 2014
  • In this study, we implemented a research for improving performance of redox flow battery (RFB) via enhancing reaction rate of vanadium reaction ($[VO]^{2+}/[VO_2]^+$) that was a rate determining step. For doing that, porous catalyst, CMK3 was employed and its perfoamance was compared with that of Vulcan(XC-72) and commercial Pt/C (Johnson-Matthey Pt 20wt.%). Cyclic voltammetry (CV) was used for inspecting reactivity, while its structural feature was measured by TEM and BET&BJH. Also, Charge-discharge trend was evaluated by single cell tests. As result, CMK3 showed 6 times better catalytic activity and twice better reversibility than Vulcan(XC-72), while it showed larger surface area than Vulcan XR due to its porous structure. Furthermore, CMK3 indicated 85% of reactivity and reversibility of commercial Pt/C despite its Pt-less situation. In single cell tests, when RFB adopted CMK3 as catalyst for positive electrode, its charge-discharge curve result was better than that adopted commercial Pt/C.

Numerical Study on Rayleigh-Taylor Instability Using a Multiphase Moving Particle Simulation Method (다상유동형 입자법을 이용한 Rayleigh-Taylor 불안정성의 수치해석)

  • Kim, Kyung Sung;Koo, Bonguk;Kim, Moo-Hyun;Park, Jong-Chun;Choi, Han-Suk;Cho, Yong-Jin
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.20 no.1
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    • pp.37-44
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    • 2017
  • Complexity of multiphase flows due to existence of more than two interface including free-surface in one system, cannot be simulated easily. Since more than two fluids affect to flows and disturb interface, non-linearities such as instabilities can be appeared. Among several instabilities on multiphase flows, one of representative is Rayleigh-taylor instability. In order to examine in importance of density disparity, several cases with numerous Atwood number are set. Moreover, investigation of influence on initial disturbance were also considered. Moving particle simulation (MPS) method, which was employed in this paper, was not widely used for multiphase problem. In this study, by adding new particle interaction models such as self-buoyance correction, surface tension, and boundary condition at interface models, MPS were developed having more strength of physics and robust. By applying newly developed multiphase MPS, considered cases are performed and compared each other. Additionally, though existence of disagreement of magnitude of rising velocity between theoretical values from linear potential theory and that of numerical simulation, agreement of tendency can be proved of similarity of result. the discordance of magnitude can be explained due to non-linear effects on numerical simulation which was not considered in theoretical result.

Characteristics of the Heteroepitaxial $Si_{1-x}Ge_{x}$ Films Grown by RTCVD Method (RTCVD 법으로 성장한 $Si_{1-x}Ge_{x}$ 에피막의 특성)

  • Chung, W.J.;Kwon, Y.K.;Bae, Y.H.;Kim, K.I.;Kang, B.K.;Sohn, B.K.
    • Journal of Sensor Science and Technology
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    • v.5 no.2
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    • pp.61-67
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    • 1996
  • The growth and characterization of heteroepitaxial $Si_{1-x}Ge_{x}$ films grown by the RTCVD (Rapid Thermal Chemical Vapor Deposition) method were described. For the growth of $Si_{1-x}Ge_{x}$ heteroepitaxial layers, $SiH_{4}$ / $GeH_{4}$ / $H_{2}$ gas mixtures were used. The growth conditions were varied to investigate their effects on the Si / Ge composition ratios, the interface abruptness and crystalline properties. The experimental data shows that the misfit threading dislocation in $Si_{1-x}Ge_{x}$ / Si heteroepitaxial film of about $400\;{\AA}$ thickness was not observed at the growth temperature of as low as $650^{\circ}C$, and the composition ratios of Si / Ge changed linearly with $SiH_{4}$ / $GeH_{4}$ gas mixing ratios in our experimental ranges. In the in-situ boron doping experiments, the doping abruptness would be controlled within several hundreds ${\AA}$/decade.

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A Study on a Multiresolution Filtering Algorithm based on a Physical Model of SPECT Lesion Detectability (SPECT 이상조직 검출능 모델에 근거한 다해상도 필터링 기법 연구)

  • Kim, Jeong-Hui;Kim, Gwang-Ik
    • Journal of Biomedical Engineering Research
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    • v.19 no.6
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    • pp.551-562
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    • 1998
  • Amultiresolution filtering algorithm based on the physical SPECT lesion detachability provides and optimal solution for SPECT reconstruction problem. Related to the previous study, we estimated the SPECT lesion detection capability by m minimum detectable lesion sizes (MDLSs), and generated m reconstruction filters which are designed to maximize the smoothing effect at a fixed MDLS-dependent resolution level $\frac{MDLS}{4\sqrt{2In2}}$. The proposed multiresolution filtering algorithm used a coarse-to-fine approach for the m-level resolution filter images obtained from these m filters for a given projection image. First, the local homogeneity is determined for every pixel of the filter images, by comparing the local variance value computed in a window centered at the pixel and the mode determined from the distribution of the local variances. Based on the local homogeneity, the pixels declared as homogeneous are chosen from the filter image of the lowest resolution, and for the other pixels the same process is repeated for the higher resolution filter images. For the non-homogeneous pixels after this pixels after this repetition process ends, the pixel values of the highest resolution filter image are substituted. From the results of the simulated experiments, the proposed multiresolution filtering algorithm showed a strong smoothing effect in the homogeneous regions and a significant resolution improvement near the edge regions of the projection images, and so produced good adaptability effects in the reconstructed images.

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The relationship between autistic features and empathizing-systemizing traits (자폐성향과 공감-체계화능력 간의 관계)

  • Cho, Kyung-Ja;Kim, Jung-K.
    • Science of Emotion and Sensibility
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    • v.14 no.2
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    • pp.245-256
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    • 2011
  • This study consists of two sections to figure out the relationship between autistic features and empathizing-systemizing traits. For the first section, the research involved 355 university students to measure their EQ, SQ-R and AQ. As a result, it is found that AQ was negatively correlated to EQ, and D score(relative difference between EQ and SQ-R of the individuals), but it was not significantly related to SQ-R. It means that the subject has high AQ if he has relatively lower EQ than SQ-R. For the second section, the subjects were divided into two groups based on their AQ score; the subjects who had a tendency of autism and the subjects who did not. The test measured how these two groups were different in terms of facial expressions' recognition according to the tendency of autism, facial expression presenting areas(whole face, eyes-alone, mouth-alone) and different types of emotions(basic and complex emotions). As a result, the subjects who had a tendency of autism were lower at judging facial expressions than the subjects who did not. Also, the results showed that the subjects judged better on the condition of basic emotions more than complex emotions, the whole face more than eyes-alone and mouth-alone. Especially, for the eyes-alone condition, the subjects who had a tendency of autism were lower at judging facial expressions than the subjects who did not. This study suggests that empathizing traits and facial expressions' recognition are related to the tendency of autism.

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Effects of aged garlic extract and endurance exercise on skeletal muscle FNDC-5 and circulating irisin in high-fat-diet rat models

  • Seo, Dae Yun;Kwak, Hyo Bum;Lee, Sung Ryul;Cho, Yeun Suk;Song, In-Sung;Kim, Nari;Bang, Hyun Seok;Rhee, Byoung Doo;Ko, Kyung Soo;Park, Byung Joo;Han, Jin
    • Nutrition Research and Practice
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    • v.8 no.2
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    • pp.177-182
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    • 2014
  • BACKGROUND/OBJECTIVES: Irisin, a newly identified hormone, is associated with energy homeostasis. We investigated whether aged garlic extract (AGE) and exercise training intervention could improve body weight, insulin sensitivity, skeletal muscle fibronectin domain containing protein 5 (FNDC-5) levels, and plasma irisin in high-fat diet (HFD). MATERIALS/METHODS: Male Sprague Dawley rats were fed a ND (normal diet, n=5) or HFD (n=28) for 6 weeks. After 6 weeks, all rats were divided into 5 groups for the next 4 weeks: ND, (normal diet, n=5), HFD (high-fat diet, n=7), HFDA (high-fat diet + aged garlic extract, n=7), HFDE (high-fat diet + exercise, n=7), and HFDEA (high-fat diet + exercise + aged garlic extract, n=7). Exercise groups performed treadmill exercises for 15-60 min, 5 days/week, and AGE groups received AGE (2.86 g/kg, orally injected) for 4 weeks. RESULTS: Significant decreases in body weight were observed in the ND, HFDE, and HFDEA groups, as compared with the HFD group. Neither intervention affected the masses of the gastrocnemius muscle or liver. There were no significant differences in glucose levels across the groups. The homeostatic model assessments of insulin resistance were significantly higher in the HFD group, as compared with the ND, HFDA, HFDE, and HFDEA groups. However, skeletal muscle FNDC-5 levels and plasma irisin concentrations were unaffected by AGE or exercise in obese rats. AGE supplementation and exercise training did not affect skeletal muscle FNDC-5 or plasma irisin, which are associated with insulin sensitivity in obese rats. CONCLUSION: Our results suggest that the protection against HFD-induced increases in body fat/weight and insulin resistance that are provided by AGE supplementation and exercise training may not be mediated by the regulation of FNDC-5 or irisin.