Expression of Pentose Phosphate Pathway-Related Proteins in Breast Cancer

Choi, Junjeong,Kim, Eun-Sol,Koo, Ja Seung IOS PRESS 2018 Disease markers Vol.2018 No.1

Development of a Pressure Sensitive Paint Technique for Low-Speed Flows and Its Application

Lee, S. J.,Kang, J. H. IOS Press 2006 Journal of visualization Vol.9 No.2

<P>Pressure sensitive paint (PSP) techniques have been used to measure the pressure distribution on a model surface in high-speed flows. In this study, we developed a PSP technique that can be applied to low-speed flows. Four PSP formulations, each comprised of a porphyrin (PtOEP or PtTFPP) and a polymer (Poly(TMSP) or RTV-118), were tested and the performance of each combination was evaluated. In the static calibration, the luminescence intensity of the PSP coatings was measured from 0 kPa to 11 kPa with 0.5, 1, and 2 kPa increments. Among the four PSP formulations tested, the combination of PtOEP and RTV-118 (PSP-3) showed the best performance. In this study, the low-pressure PSP technique using PSP-3 was applied to an oblique impinging subsonic jet to measure pressure field distributions on the impingement plate at various angles of the oblique jet. For comparison, the flow over the impingement plate was visualized using an oil-film method. </P>

Propagation of Orifice- and Nozzle-Generated Vortex Rings in Air

Syed, A. H.,Sung, H. J. IOS Press 2009 JOURNAL OF VISUALIZATION Vol.12 No.2

<P>The effect of the exit geometry of a vortex ring generator was studied experimentally. Two types of exit geometries were chosen: an orifice and a nozzle. Vortex rings were generated by pushing a solenoid-valve-controlled, pressurized-air jet through the circular opening of the orifice or nozzle. Experiments were performed over a wide range of initial Reynolds number (450 ⩽ Re ⩽ 4580) and length-to-diameter ratio (0.7 ⩽ L / D ⩽ 7.0) of the air jet. The exit geometry was found to significantly influence the entire course of propagation of the vortex ring. The orifice-generated vortex ring had superior characteristics to that produced by the nozzle under the same conditions. The vorticity generated along the wall in the orifice exit plane had a negligible effect on the circulation of the vortex ring within the specified range of Reynolds number. Compared to the nozzle-generated vortex ring, the orifice-generated ring showed reduced initial vorticity losses and less diffusive entrainment of ambient fluid. The vortex rings produced by the orifice attained more circulation, less entrainment of ambient fluid and hence rapidly propagated through longer distances in comparison to the nozzle-generated rings. </P>

Ultrasonic Visualization of Dynamic Behavior of Red Blood Cells in Flowing Blood

Paeng, D.-G.,Nam, K.-H. IOS Press 2009 JOURNAL OF VISUALIZATION Vol.12 No.4

<P>It is well known that the scatter of ultrasound by blood is mainly attributed to red blood cells (RBCs) and RBC aggregation. In the present review, researches of hemodynamic influence on RBC aggregation and ultrasound backscatter from blood were overviewed. A mock flow loop and a cylindrical chamber were employed to produce various blood flows, such as pulsatile, oscillatory, and rotational flow. The 'black hole' (BLH), a dark hole at the tube center surrounded by bright zone in the cross sectional B-mode image and 'bright collapsing ring' (BRCR) phenomena, appearance of bright ring at the periphery and collapse of it at the center during a pulsatile cycle, were observed under pulsatile flow. The combined effects of shear rate and flow acceleration on RBC aggregation were suggested as a possible mechanism for these phenomena. The stroke volume-dependence of the 'bright ring' phenomenon under oscillatory flow could also be explained by flow acceleration. The enveloped echo images from rotational flow in a compact blood chamber showed the spatial and temporal variations of RBC aggregation, which varied with the mammalian species. In the stenotic model, it was found that the echogenic variation increased locally at a distance of three tube diameters downstream from the stenosis during decelerating period, which was proposed to be mainly due to flow turbulence. The similar 'bright ring' was also observed from in vivo human carotid artery in harmonic imaging. </P>

Investigation on the Respiratory Airflow in Human Airway by PIV

Kim, S. K.,Chung, S. K. IOS Press 2009 JOURNAL OF VISUALIZATION Vol.12 No.3

<P>The creation of the accurate transparent flow passage is essential to analyze the flow inward a geometrically complex flow passage like human airway by PIV. We established the procedure to create a transparent box containing a model of the human airway for PIV measurements. A flow passage includes the whole human upper airway, nasal cavities, larynx, trachea, and 2 generations of bronchi. The phase averaged mean and RMS velocity distributions in sagittal and coronal planes are obtained for 7 phases in a respiratory period by tomographic PIV. Some physiologic conjectures are obtained. The main stream went through the backside of larynx and trachea in inspiration and the frontal side in expiration. </P>

PIV Measurements on the Change of the Three-Dimensional Wake Structures by an Air Spoiler of a Road Vehicle

Kim, J. S.,Sung, J.,Kim, S.,Kim, J. S. IOS Press 2008 JOURNAL OF VISUALIZATION Vol.11 No.1

<P>The three-dimensional vortical structures formed in the wake behind a road vehicle were measured using a particle image velocimetry (PIV) technique and the change of the structures by the existence of an air spoiler was investigated. The measurements were carried out in several x-y, y-z and z-x planes to obtain full three-dimensional flow fields, including an out-of-plane velocity component, obtained by interpolating the velocities in the other plane. Then, the velocity gradient tensor is evaluated to obtain the vortex core by the λ<TEX>$_2$</TEX>-definition. The relationship between streamwise, longitudinal and spanwise vortices is systematically analyzed by overlapping the vortex lines and vortex cores and the whole flow topology is compared in both cases with and without an air spoiler. As a result, an air spoiler was found to weaken the C-pillar vortices producing strong wing tip vortices, which reduce downwash flow and longitudinal vortices increase in the vertical direction. The recirculation zone formed when an air spoiler is installed is higher and narrower than without a spoiler. </P>

Draining from Cylindrical Tanks with Vane-Type Suppressors – A PIV Study

Sohn, C.H.,Ju, M.G.,Gowda, B.H.L. IOS Press 2009 JOURNAL OF VISUALIZATION Vol.12 No.4

<P>The vortexing phenomenon that occurs in a cylindrical container is studied using PIV. The influence of the vane-type suppressors which prevent the vortex formation is investigated. An attempt has been made to understand the mechanism that is responsible for vortex suppressing. There is a strong updraft generated due to the suppressors which leads to annihilation of vorticity which appears to be responsible for vortex suppression. </P>

Rac GTPases in Human Diseases

Pai, Sung-Yun,Kim, Chaekyun,Williams, David A. IOS Press 2010 Disease markers Vol.29 No.3

<P>Rho GTPases are members of the Ras superfamily of GTPases that regulate a wide variety of cellular functions. While Rho GTPase pathways have been implicated in various pathological conditions in humans, to date coding mutations in only the hematopoietic specific GTPase, <I>RAC2</I>, have been found to cause a human disease, a severe phagocytic immunodeficiency characterized by life-threatening infections in infancy. Interestingly, the phenotype was predicted by a mouse knock-out of <I>RAC2</I> and resembles leukocyte adhesion deficiency (LAD). Here we review Rho GTPases with a specific focus on Rac GTPases. In particular, we discuss a new understanding of the unique and overlapping roles of Rac2 in blood cells that has developed since the generation of mice deficient in Rac1, Rac2 and Rac3 proteins. We propose that Rac2 mutations leading to disease be termed LAD type IV.</P>

Induction of quinone reductase by allylisothiocyanate (AITC) and the N-acetylcysteine conjugate of AITC in Hepa1c1c7 mouse hepatoma cells

Hwang, Eun-Sun,Lee, Hyong Joo IOS Press 2006 Biofactors Vol.26 No.1

<P>Cruciferous vegetables contain a series of relatively unique secondary metabolites of amino acids, called glucosinolates, from which isothiocyanates (ITC) can be generated. While glucosinolates are not thought to be bioactive directly, ITC appear to have anticarcinogenic activity. Sinigrin, the predominant aliphatic glucosinolate in cruciferous vegetables, is hydrolyzed to yield allylisothiocyanate (AITC), which, following absorption and metabolism in humans, is excreted in the urine as an N-acetyl-cysteine (NAC) conjugate. AITC possesses numerous biochemical and physiological activities. This study examined the induction of quinine reductase (QR) by AITC and synthetic AITC-NAC in Hepa1c1c7 murine hepatoma cells. AITC and AITC-NAC inhibited cell growth in a dose-dependent manner. The induction of QR activity and QR mRNA expression was dose-responsive over a range of 0.1-2.5 μM. AITC caused 2.0- and 3.1-fold inductions of QR with 1- and 2-μM treatments, respectively. By comparison, 1 and 2 μM AITC-NAC caused 2.9- and 3.7-fold inductions of QR, respectively. Considering the potential of ITC to prevent cancer, these results provide a basis for the use of NAC-ITC conjugates as chemopreventive agents.</P>

Estimation of spectrum requirements for mobile networks with self-similar traffic, handover, and frequency reuse

Yang, W.S.,Yang, E.S.,Kim, H.J.,Kim, D.K. IOS PRESS 2010 Mobile information systems Vol.6 No.4