• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8027-8034
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• 2014

Genetic instability contributes to the development and progression of gastric cancer, one of the leading causes of cancer death worldwide. Microsatellite instability (MSI) has been hypothesized to be involved in carcinogenesis, althgough its mechanisms and exact roles in gastric cancer remain largely unknown. Our aim was to identify associated clinicopathological characteristics and prognostic value of MSI in gastric cancer and precancerous lesions including gastritis, metaplasia, dysplasia, and adenoma. Because mitochondrial DNA has a different genetic system from nuclear DNA, the results of both nuclear MSI and mitochondrial MSI in gastric cancer were reviewed. This review provides evidence that genetic instability of nuclear and mitochondrial DNAs contributes to early stages of gastric carcinogenesis and suggests possible roles in predicting prognosis.

• Journal of Families and Better Life
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• v.15 no.1
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• pp.191-200
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• 1997

The purpose of this research was to test a model of intergenerational transmission of marital instability. An important aspect of the present study was to test the direct and indiect intergenerational transmission processes of marital instability. This study revealed four very important findings. First the effects of parental divorce on children's marital instability were both direct and indirect through mate selection risk factors marital quality and marital commitment. Second premarital backgrounds such as socioeconomic status of parents and relative heterogeneity between spouse before marriage were important to explain one's marital relationship. Third the higher the barriers the higher the marital commitment. Fourth marital quality and marital commitment were important predictors of marital instability. Taken together this study supports the intergenerational transmission perspective that exposure to conflict marriage in one's own childhood would forecast lower marital sat sfaction higher conflict and higher marital instability in the marital relationship. The findings from this study also underline the importance of predisposing marital characteristics such as parental socioeconomic status and relative heterogeneity in explaining marital relationship.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03a
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• pp.18-21
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• 1999

The wrinkling of thin sheet metal induced by compressive instability is one of major defects in sheet metal forming processes. compressive instability is influence by many factors such as mechanical properties of the sheet material geometry of the sheet contact conditions and plastic anisotropy. The analysis of compressive instability in a plastically deforming body is rather difficult because the effects of the above-mentioned factors are rather complex and the instability behavior may show swide variations even for small deviations of the factors. in this work the bifurcation theory is introduced for the finite elemental analysis of the instability behavior of a thin sheet with initially sound geometry and property. All the above-mentioned factors are conveniently considered by the finite element method. The instability limit is found by introducing a criterion scheme into the incremental analysis and the post-bifurcation behavior is analyzed by introducing the branching scheme. Wrinkling initiation and growth in the deep drawing process are analyzed.

• Nuclear Engineering and Technology
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• v.38 no.1
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• pp.69-80
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• 2006

Fluid-elastic instability in an air-water two-phase cross-flow has been experimentally investigated using two different arrays of straight tube bundles: normal square (NS) array and rotated square (RS) array tube bundles with the same pitch-to-diameter ratio of 1.633. Experiments have been performed over wide ranges of mass flux and void fraction. The quantitative tube vibration displacement was measured using a pair of strain gages and the detailed orbit of the tube motion was analyzed from high-speed video recordings. The present study provides the flow pattern, detailed tube vibration response, damping ratio, hydrodynamic mass, and the fluid-elastic instability for each tube bundle. Tube vibration characteristics of the RS array tube bundle in the two-phase flow condition were quite different from those of the NS array tube bundle with respect to the vortex shedding induced vibration and the shape of the oval orbit of the tube motion at the fluid-elastic instability as well as the fluid-elastic instability constant.

• 한국전산유체공학회:학술대회논문집
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• 2001.05a
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• pp.99-104
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• 2001

This paper deals with the development of shock stable scheme that is free from shock instability. Roe's FDS is known to preserve good accuracy but to suffer from shock instability, i.e. the carbuncle phenomenon. As the first step toward the shock stable scheme, Roe's FDS is compared with HLLE scheme to identify the source of shock instability. Then control function f is introduced into the pressure term in Roe's FDS to cure shock instability. Various numerical tests concerned with shock instability are performed to demonstrate the shock stability of the proposed scheme.

• Journal of computational fluids engineering
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• v.16 no.1
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• pp.1-6
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• 2011

Flow instability is investigated in a two-dimensional channel with thin baffles placed symmetrically in the vertical direction and periodically in the streamwise dircetion. At low Reynolds numbers, the flow is steady and symmetric. Above a critical Reynolds number, the steady flow undergoes a Hopf bifurcation leading to unsteady periodic flow. As Reynolds number further increases, we observe the onset of secondary instability. At high Reynolds numbers, the two-dimensional periodic flow becomes three dimmensional. To identify the onset of secondary instability, we carry out Floquet stability analysis. We obseved the transition to 3D flow at a Reynolds number of about 125. Also, we computed dominant spanwise wavenumbers near the critical Reynolds number, and visualized vortical structures associated with the most unstable spanwise wave.

• Journal of the Korean Society of Visualization
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• v.3 no.2
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• pp.45-50
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• 2005

Electro-osmotic flow (EOF) instability in a microchannel has been experimentally investigated using a micro-PIV system. The micro-PIV system consisting of a two-head Nd:Yag laser and cooled CCD camera was used to measure instantaneous velocity fields and vorticity contours of the EOF instability in a T-shape glass microchannel. The electrokinetic flow instability occurs in the presence of electric conductivity gradients. Charge accumulation at the interface of conductivity gradients leads to electric body forces, driving the coupled flow and electric field into an unstable dynamics. The threshold electric field above which the flow becomes unstable and rapid mixing occurs is about 1000V/cm. As the electric field increases, the flow pattern becomes unstable and vortical motion is enhanced. This kind of instability is a key factor limiting the robust performance of complex electrokinetic bio-analytical devices, but can also be used for rapid mixing and effective flow control fer micro-scale bio-chips.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.141-150
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• 2002

Numerical simulations based on the ALE finite element method are carried out to examine the aerodynamics of an oscillating circular cylinder when the separated shear flows around the cylinder are stimulated by periodic jet excitation with a shear layer instability frequency. The excitation is applied to the flows from two points on the cylinder surface. The numerical results showed that the excitation with a shear layer instability frequency can reduce the negative damping and thereby stabilize the aerodynamics of the oscillating cylinder. The change of the lift phase seems important in stabilizing the cylinder aerodynamics. The change of lift phase is caused by the merger of the vortices induced by the periodic excitation with a shear layer instability frequency, and the vortex merging comes from the high growth rate, the rapid increase of wave number and decrease of phase velocity for the periodic excitation in the separated shear flows.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.287-293
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• 2005

Most of all combustion system has combustion instability. It is a serious problem in combustion system. Unstable injection is one of the source of combustion instability. The experimental investigation of spray characteristics for simplex swirl injector were conducted experimentally. Two kerosene based fuels were chosen as the atomizing fluid. As the major operating parameters, fuel temperature and injection pressure were chosen, and varied in the range from 253 K to 293 K and from 0.2 MPa to 1.0 MPa, respectively. Direct spray images and mean diameter were measured for the various combination of operating parameters in the flow field. The results of present study show that the injection pressure and spray cone angle are fluctuated at specific conditions while it is continuous steady injection. As the fuel temperature changes continuously, spray cone angle varies discontinuously through the region of injection instability.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.560-562
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• 2015

It is well known that spinal instability should be evaluated in the standing lateral position. Standing dynamic flexion and extension radiographs are usually used to assess spinal instability. Here, we report a patient who experienced distraction instability while in the supine position rather than the standard standing position. To our knowledge, this is the first report of lying-down instability undetected on standing dynamic flexion and extension radiographs. We discuss the pathophysiological mechanism of this uncommon but possible entity and provide a review of the literature.