• Journal of Korean Neurosurgical Society
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• v.52 no.6
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• pp.551-554
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• 2012

Alternative to carotid endarterectomy, carotid artery stenting (CAS) can be performed for symptomatic severe stenosis of internal carotid artery, especially for high-risk patients. Among several complications after CAS, subacute in-stent thrombosis is rare but important, because patient's condition can deteriorate rapidly. Subacute in-stent thrombosis with carotid artery occlusion can be managed by superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. We report two cases of STA-MCA anastomosis for internal carotid artery occlusion by subacute in-stent thrombosis after CAS.

• Journal of Sensor Science and Technology
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• v.15 no.1
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• pp.47-52
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• 2006

This paper describes the design, fabrication and characteristics of a buckling microvalve using a MCA (multilayer ceramic actuator). The mechanical and fluidic analysis are done by finite element method. The designed structure is normally closed microvalve using buckling effect, which is consist of three separate structures; a valve seat die, an actuator die and a small piezoelectric actuator. The flow rate of the fabricated MCA valve was 0-8.13 ml/min at the applied pressure of 0-50 kPa. Maximum non-linearity was 2.24 % FS at a duty cycle of 50 %. The maximum pressure was 230 kPa and the leak rate was $3.03{\times}10^{-8}\;Pa{\cdot}m^{3}/cm^{2}$ at a supply voltage of 100 V.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.66-70
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• 2008

The propagation of a mixed-mode crack in soda-lime silica glass is modeled by movable cellular automata (MCA). In this model, a special fracture criterion is used to describe the process of crack initiation and propagation. The results obtained using the MCA criterion are compared to those obtained from other crack initiation criteria, The crack resistance curves and bifurcation angles are determined for various loading angles. The MCA results are in close agreement with results obtained using the maximum circumferential tensile stress criterion.

• Journal of Acupuncture Research
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• v.18 no.6
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• pp.135-140
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• 2001

Objective : To investigate the effects of Acupuncture therapy on the migraineur by way of the change of the Cerebral blood flow. Methods : 6 migraineurs were inserted in acupoints on GV16, G20, S8 during 2 weeks. and, Mean Velocity (MV) and Pulsatility Index (PI) of MCA, PCA, ACA, BA were measured before and after treatments of 2 weeks, respectively. Results : MV of MCA of the migraineurs was decreased very much by 13.3%, and PI was decreased much by 10.4%. However, MV and PI of BA changed little. Conclusion : It is observed that Acupuncture therapy reduces pains of migraineur through decreasing Cerebral blood flow like MCA.

• Journal of the Korean Home Economics Association
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• v.37 no.5
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• pp.31-48
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• 1999

This research was to assess the high school girls' need about the computer assisted instruction(CAI) in the Home Economics Curriculum. In One-way ANOVA, the high school girls' need about the CAI differs in the educational level of the father and the mother, the preference for the Home Economics, the involvement with the Home Economics and the preference for a teaching method of Home Economics. MCA was done to assess the independent explanatory power of predictory variables. The educational level of father and mother were included separately in different model. The MCA that the educational level of father was included in, The most influential variable was the preference for the Home Economics and the involvement with Home Economics was the second. The MCA that the educational level of mother was included in, The most influential variable was the preference for the Home Economics and the educational level of mother was the second.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.437-442
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• 2001

For ischemic cerebrovascular disease, it is well known that early luxury perfusion is related to a good clinical outcome and single photon emission computed tomography(SPECT) has the potential for providing useful information about regional cerebral blood flow. We report one case of Rt. MCA infarction mainly treated by oriental medicine and revealed luxury perfusion without thrombolysis. In acute stage, neurological deficits of the patient were very severe. 99mTc-HMPAO SPECT images obtained 10days after the attack showed large perfusion defect in the Rt. MCA territory. We followed up 99mTc-HMPAO SPECT 40days after the ictus. Despite of the poor early perfusion, we found considerably improved perfusion and neurological improvement.

• International Journal of Computer Science & Network Security
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• v.21 no.5
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• pp.168-174
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• 2021

The Cognitive radio (CR) is evolving technology for managing the spectrum bandwidth in wireless network. The security plays a vital role in wireless network where the secondary users are trying to access the primary user's bandwidth. During the allocation the any malicious user either he pretends to be primary user or secondary user to access the vital information's such as credentials, hacking the key, network jam, user overlapping etc. This research paper discusses on various types of attack and to prevent the attack in cognitive radio network. In this research, secondary users are identified by the primary user to access the primary network by the secondary users. The secondary users are given authorization to access the primary network. If any secondary user fails to provide the authorization, then that user will be treated as the malicious user. In this paper two approaches are suggested one by applying elliptic curve cryptography and the other method by using priority-based service access.

• Journal of Korean Neurosurgical Society
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• v.61 no.2
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• pp.267-276
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• 2018

Objective : The beneficial effect of hypothermia after hemicraniectomy in malignant middle cerebral artery (MCA) infarction has been controversial. We aim to investigate the safety and clinical efficacy of hypothermia after hemicraniectomy in malignant MCA infarction. Methods : From October 2012 to February 2016, 20 patients underwent hypothermia (Blanketrol III, Cincinnati Sub-Zero, Cincinnati, OH, USA) at $34^{\circ}C$ after hemicraniectomy in malignant MCA infarction (hypothermia group). The indication of hypothermia included acute cerebral infarction >2/3 of MCA territory and a Glasgow coma scale (GCS) score <11 with a midline shift >10 mm or transtentorial herniation sign (a fixed and dilated pupil). We retrospectively collected 27 patients, as the control group, who had undergone hemicraniectomy alone and simultaneously met the inclusion criteria of hypothermia between January 2010 and September 2012, before hypothermia was implemented as a treatment strategy in Dong-A University Hospital. We compared the mortality rate between the two groups and investigated hypothermia-related complications, such as postoperative bleeding, pneumonia, sepsis and arrhythmia. Results : The age, preoperative infarct volume, GCS score, National institutes of Health Stroke Scale score, and degree of midline shift were not significantly different between the two groups. Of the 20 patients in the hypothermia group, 11 patients were induced with hypothermia immediately after hemicraniectomy and hypothermia was initiated in 9 patients after the decision of hypothermia during postoperative care. The duration of hypothermia was $4{\pm}2days$ (range, 1 to 7 days). The side effects of hypothermia included two patients with arrhythmia, one with sepsis, one with pneumonia, and one with hypotension. Three cases of hypothermia were discontinued due to these side effects (one sepsis, one hypotension, and one bradycardia). The mortality rate of the hypothermia group was 15.0% and that of the control group was 40.7% (p=0.056). On the basis of the logistic regression analysis, hypothermia was considered to contribute to the decrease in mortality rate (odds ratio, 6.21; 95% confidence interval, 1.04 to 37.05; p=0.045). Conclusion : This study suggests that hypothermia after hemicraniectomy is a viable option when the progression of patients with malignant MCA infarction indicate poor prognosis.

• Journal of Korean Neurosurgical Society
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• v.45 no.1
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• pp.11-15
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• 2009

Objective : The aim of study was to review our patient population to determine whether there is a critical aneurysm size at which the incidence of rupture increases and whether there is a correlation between aneurysm size and location. Methods : We reviewed charts and radiological findings (computed tomography (CT) scans, angiograms, CT angiography, magnetic resonance angiography) for all patients operated on for intracranial aneurysms in our hospital between September 2002 and May 2004. Of the 336 aneurysms that were reviewed, measurements were obtained from angiograms for 239 ruptured aneurysms by a neuroradiologist at the time of diagnosis in our hospital. Results : There were 115 male and 221 female patients assessed in this study. The locations of aneurysms were the middle cerebral artery (MCA, 61), anterior communicating artery (ACoA, 66), posterior communicating artery (PCoA, 52), the top of the basilar artery (15), internal carotid artery (ICA) including the cavernous portion (13), anterior choroidal artery (AChA, 7), A1 segment of the anterior cerebral artery (3), A2 segment of the anterior cerebral artery (11), posterior inferior cerebellar artery (PICA, 8), superior cerebellar artery (SCA, 2), P2 segment of the posterior cerebral artery (1), and the vertebral artery (2). The mean diameter of aneurysms was $5.47{\pm}2.536\;mm$ in anterior cerebral artery (ACA), $6.84{\pm}3.941\;mm$ in ICA, $7.09{\pm}3.652\;mm$ in MCA and $6.21{\pm}3.697\;mm$ in vertebrobasilar artery. The ACA aneurysms were smaller than the MCA aneurysms. Aneurysms less than 6 mm in diameter included 37 (60.65%) in patients with aneurysms in the MCA, 43 (65.15%) in patients with aneurysms in the ACoA and 29 (55.76%) in patients with aneurysms in the PCoA. Conclusion : Ruptured aneurysms in the ACA were smaller than those in the MCA. The most prevalent aneurysm size was 3-6 mm in the MCA (55.73%), 3-6 mm in the ACoA (57.57%) and 4-6 mm in the PCoA (42.30%). The more prevalent size of the aneurysm to treat may differ in accordance with the location of the aneurysm.

• The Journal of Internal Korean Medicine
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• v.28 no.2
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• pp.250-261
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• 2007

Objectives : The purpose of this study was to evaluate the blood flow using doppler ultrasound of the MCA, ACA, PCA, BA, ICA in the patients with risk factor for stroke. Methods : 110 patients with risk factor for stroke were selected who had hypertension, diabetes mellitus, hyperlipidemia, or heart disease, as well as 89 healthy adults who did not have any symptoms of those diseases. To evaluate the blood flow, the Vs and Vm of the MCA, ACA, PCA, BA, and ICA in the two groups were measured. Result : In normal healthy adults, subjects showed a decrease in the Vs and Vm: with advancing in age, there was a significant difference in the Vs of MCA, PCA, BA, and ICA. There was a significant difference in the Vm of MCA, PCA, BA, and ICA. In normal healthy adults, females showed high velocities in all examined vessels. There was a significant difference in the Vs of BA. There was a significant difference in the Vm of BA, and ICA. There was a decrease in the Vs, and Vm of all examined vessels of patients with risk factors for stroke in comparison with normal healthy adults. There was no significant difference in the Vs. There was a significant difference in the Vm of MCA, ACA, and PCA. Results were the same between patients aged under 50 and total patients in the Vs and Vm of examined vessels. There were differences between patients aged over 50 and total patients in the Vs of MCA, PCA, BA and for patients aged over 50; patients with risk factor for stroke who had hypertension, diabetes mellitus, hyperlipidemia, or heat disease has higher Vs than healthy adults. Conclusions : There was a significant difference in the blood flow velocity between patients with risk factors for stroke and healthy adults. However, this result was different from results of comparison of TCD findings between patients and healthy individuals by age. Therefore, more detailed studies about aged patients are needed.