• The Korean Journal of Physiology and Pharmacology
• /
• v.13 no.1
• /
• pp.23-26
• /
• 2009

During operations, neurosurgeons usually perform multiple temporary occlusions of parental artery, possibly resulting in the neuronal damage. It is generally thought that neuronal damage by cerebral ischemia is associated with extracellular concentrations of the excitatory amino acids. In this study, we measured the dynamics of extracellular glutamate release in 11 vessel occlusion(VO) model to compare between single occlusion and repeated transient occlusions within short interval. Changes in cerebral blood flow were monitored by laser-Doppler flowmetry simultaneously with cortical glutamate level measured by amperometric biosensor. From real time monitoring of glutamate release in 11 VO model, the change of extracellular glutamate level in repeated transient occlusion group was smaller than that of single occlusion group, and the onset time of glutamate release in the second ischemic episode of repeated occlusion group was delayed compared to the first ischemic episode which was similar to that of single 10 min ischemic episode. These results suggested that repeated transient occlusion induces less glutamate release from neuronal cell than single occlusion, and the delayed onset time of glutamate release is attributed to endogeneous protective mechanism of ischemic tolerance.

• The KIPS Transactions:PartB
• /
• v.13B no.1 s.104
• /
• pp.35-46
• /
• 2006

The dynamic change of background and moving objects is an important factor which causes the problem of occlusion in tracking moving objects. The tracking accuracy is also remarkably decreased in the presence of occlusion. We therefore propose an active fusion model which is robust against partial occlusions that are occurred by background and other objects. The active fusion model is consisted of contour-based md region-based snake. The former is a conventional snake model using contour features of a moving object and the latter is a regional snake model which considers region features inside its boundary. First, this model classifies total occlusion into contour and region occlusion. And then it adjusts the confidence of each model based on calculating the location and amount of occlusion, so it can overcome the problem of occlusion. Experimental results show that the proposed method can successfully track a moving object but the previous methods fail to track it under partial occlusion.

• Journal of Korean Medicine Rehabilitation
• /
• v.19 no.1
• /
• pp.11-21
• /
• 2009

Objectives : This study was performed to investigate the effects of Semen Persicae(SP) on muscle type change and vascularization effect by measuring expression of Myosin heavy chain (MHC) and Vascular endothelial growth factor (VEGF) protein in the Middle cerebral artery occlusion(MCAo) rats. Methods : The middle cerebral artery was occluded, SP extraction was administrated for 4 days. The effects of SP on muscle type change and vascularization were measured. Results : 1. VEGF protein expressions in the Semen Persicae oral administration group of MCAo group were increased compared to the control group. 2. There were no significant difference between the Semen Persicae oral administration of MCAo group and the control group in MHC isoform (Type I, Type IIa) expression change. Conclusions : The present study demonstrates the effect of Semen Persicae in the vascularizing after ischemia, but has no significant effect in musle type change and the improvement of musle atrophy.

• The Journal of the Korean dental association
• /
• v.50 no.1
• /
• pp.6-12
• /
• 2012

As in all other parts in the body, oral tissue also undergoes dramatic changes with increasing age. Since these changes occasionally go beyond physiological scope, which may result in pathological changes, it is essential for dentist to understand changes caused by normal aging process. With increasing age, tooth morphology and occlusion also varies, especially loss of hard tissue, which is taking place in lifelong time, occurs as a result of tooth wear. When this loss of hard tissue is presented rapidly or excessively, functional and esthetical problems are raised, resulting in lowering quality of life of patient as well as making dental treatment for oral rehabilitation even more complex. Therefore, based on understanding of change in occlusion with increasing age, strategic approaches for maintenance of oral health in both functional and esthetic aspect are required as appropriate restoration and maintenance for progressive tooth wear enables desirable occlusal relationship. Carefully planned-restorative treatment in accordance with changed occlusal relationship is also required in the same context. Instead of taking changes in oral tissue as only a consequence of ageing, it is vital to educate patient and his or her guardian, assuring maintenance of oral hygiene and regular dental check-up are of utmost importance for improved oral health.

• The korean journal of orthodontics
• /
• v.8 no.1
• /
• pp.27-37
• /
• 1978

In order to know the variation of the associated craniofacial skeletal angle and linear distance according to the change of gonial angle, the roentgenographic cephalo metric study was undertaken in Korean normal cephalometric analysis and eletric computer. The fallowing results were optained. 1) The size of gonial angle is mainly depend on the lower gonial angle. The mean of upper gonial gngle is almost same in normal occlusion group$^*$ and malocclusion group. 2) It was resulted on normal group and malocclusion group by F test that the number of parameters that were significant at 5% level of confidence were 14 parameters in normal occlusion group and 22 parameters in malocclusion group. 3) Ramus height and mandibular body length increased and facial ratio is decreased as gonial angle decreased. 4) MP-T, overbite depth and Y-axis angle is not related to gonial angle in normal occlusion group, but in moloclusion group, as gonial angle decreased, MP-T and overbite depth is increased and Y-axis angle is decreased. 5) SN-MP, OP-MP, PP-MP is increased as gonial anglel increased, it was mainly depend on the lower gonial angle.

• Journal of TMJ Balancing Medicine
• /
• v.9 no.1
• /
• pp.4-11
• /
• 2019

Objectives: Although intraoral balancing appliance therapy has been used effective to several diseases, verification studies through cerebral diseases are poorly reported so far. Thus we investigated the effect of tooth-cut induced dental malocclusion against mouse model of ischemic stroke. Methods: Tooth-cut and 90 min middle cerebral artery occlusion (MCAO) were loaded to C57BL/6 male mice, and total infarct area, neurological deficit scores (NDS), histological change of hippocampal region were observed. Production levels of reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) in cerebral tissue were also measured. Results: The longer the tooth-cut period, the greater the area of cerebral infarction caused by MCAO, and NDS began to increase as the tooth was cut, and the results were more negative when MCAO was loaded. Histological change of hippocampal cells was significant when tooth-cut was maintained for 7 days. Those damages were thought to depend on the generation of ROS and iNOS in brain tissue. Conclusions: Since tooth-cut increased total area of cerebral infarction due to MCAO in mice, it is able to be confirmed that anomaly of the temporomandibular occlusion can affect neurological diseases.

• Journal of Biomedical Engineering Research
• /
• v.24 no.5
• /
• pp.421-425
• /
• 2003

In this study the occlusion of dural-sac. the outer membrane of spinal cord in the lumbar region. was quantitatively analyzed using one motion segment finite element model. Occlusion was quantified by calculating cross sectional area change of dural-sac for different compressive impact duration (loading rate) due to bony fragment at the posterior wall of the cortical shell in vertebral body. Dural-sac was occluded most highly in the range of 8∼12 msec impact duration by the bony fragment intruding into the spinal canal. $\Delta$t = 400 msec case 4 % cross sectional area change was calculated. which is the same as the cross sectional area change under 6 kN of static compressive loading.

• The korean journal of orthodontics
• /
• v.5 no.1
• /
• pp.51-56
• /
• 1975

In orthodontic field, the study on gnathostatic model is very important to the diagnosis and analysis of malocclusion. The purpose of this study is to observe that relation of orbital plane and upper canine in Koreans. We selected 230 cases with normal occlusion, 124 male and 106 female cases aged from 12 years to 25 years, to prepare 230 gnathostatic models, and measured the distance from midpoint of mesio-distal distance of upper canine to orbital plane in gnathostatic model. The results obtained were as follows: 1) The mean value of the distance from upper canine to orbital plane showed no significant change with age. 2) The mean value of the distance from the upper canine to orbital plane was -3.11mm in male and -3.84mm in female. 3) The orbital plane passed through the upper canine in normal occlusion of Koreans.

• Journal of Korean Neurosurgical Society
• /
• v.41 no.3
• /
• pp.200-203
• /
• 2007

We describe a case that showed augmention of the superficial temporal artery [STA] pedicle's patency 15 months after extracranial to intracranial [EC-IC] bypass surgery for a carotid artery occlusion with contralateral intracranial internal carotid artery stenosis. It is rare that meager patency of the STA pedicle in the early postoperative angiogram can be become well augmented with time where most branches of the middle cerebral artery [MCA] are robustly filled with blood from the STA. A 28-year-old woman with a history of a previous left hemispheric stroke presented with slurred speech after several bouts of seizure. Magnetic resonance imaging showed a new infarct on the right hemisphere in addition to an old infarct on the left hemisphere. Carotid angiography revealed stenosis of the right carotid siphon and occlusion of the left carotid artery. The patient underwent EC-IC bypass on the right side. Even though the early postoperative angiogram showed meager filling of MCA with no significant stenotic lesion change, a subsequent angiogram taken 15 months later, demonstrated a widely patent STA pedicle with occlusion of the previous intracranial stenotic lesion. Selected cases with an inaccessible intracranial stenotic lesion can benefit from EC-IC bypass surgery; however, its clear indication should first be established.

• The KIPS Transactions:PartA
• /
• v.17A no.4
• /
• pp.189-196
• /
• 2010

This paper presents an improved marker detection algorithm using hybrid features such as corner, line segment, region, and adaptive threshold values, etc. In usual augmented reality environments, there are often marker occlusion and poor illumination. However, existing ARToolkit fails to recognize the marker in these situations, especially, partial concealment of marker by user, large change of illumination and dim circumstances. In order to solve these problems, the adaptive threshold technique is adopted to extract a marker region and a corner extraction method based on line segments is presented against marker occlusions. In addition, a compensating method, corresponding the marker size and center between registered and extracted one, is proposed to increase the template matching efficiency, because the inside marker size of warped images is slightly distorted due to the movement of corner and warping. Therefore, experimental results showed that the proposed algorithm can robustly detect the marker in severe illumination change and occlusion environment and use similar markers because the matching efficiency was increased almost 30%.