• Radiation Oncology Journal
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• v.13 no.3
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• pp.205-214
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• 1995

Purpose : To investigate the effect of Ginkgo biloba extract (GBE) on hypoxic cell fraction and metabolic status in fibrosarcoma (FSa II) of C3H mouse. Materials and Methods : Fibrosarcoma (FSa II) 6 mm in diameter, growing in the right hindleg muscle of C3H mouse was used for estimation of hypoxic cell fraction using comparison of $TCD_{50}$. Radiation was given one hour after administration of GBE (100 mg/kg. i.p.) with or without priming dose of GBE (100 mg/kg, i.p.) given 24 hours earlier. Radiation was also given under air breathing condition or clamp hypoxia without GBE as controls. $^{31}p$ NMR spectroscopy was performed before and one hour after administration of GBE with or without priming dose of GBE. Results : $TCD_{50/120's}$ were 81.7 (77.7-86.0) Gy when irradiated under clamped hypoxia 69.6 (66.8-72.5) Gy under air breathing condition. 67.5 (64.1-71.1) Gy with a single dose of GBE (100 mg/kg) given one hour before irradiation, and 62.2 (59.1-65.5) Gy with two doses of GBE given at 25 hours and one hour before irradiation. The hypoxic cell fractions, estimated from $TCD_{50/120's}$, were $10.6{\%}$ under air breathing condition, $7.2{\%}$ after a single dose of GBE, and $2.7{\%}$ after two doses of GBE. The results of $^{31}P$ NMR spectroscopy were as follow. PCr/Pi ratio was $0.27{\pm}0.04$ and $0.40{\pm}0.04$ before and one hour after a single dose of GBE (p<0.05), respectively, without priming dose and $0.30{\pm}0.02$ and $0.71{\pm}0.04$, respectively, with priming dose (p<0.01). These findings indicate that the metabolic status is slightly improved after a single dose and markedly after repeated administrations. Conclusion : GBE decreases the hypoxic cell fraction and imprvoes the meta bolic status of tumor, probably by increasing the blood flow and delivery of oxygen and nutrients, resulting in increased radiosensitivity of tumor.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.26-30
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• 1999

Background : The origin of P300 was still on debate nbut thought to be in the frontal, temporal or parietal lobe. As the transcranial doppler ultrasonography(TCD) gives us and opportunity to observe hemodynamic chaged dynamically and the middle cerebral artery feeds these ares of the hemisphere, we observed the change of mean flow velocity of MCA during the event related potential test(ERP) to determine the role of these structures in P300 generation. Method : Twenty normal subjects(male : 13, age : 24-29 years) performed ERP. An auditory oddball pardigm was used to elicit the ERPs. TCD examination was performed with 2-MHz probe monitoring the left MCA(Transscan, EME). After signal identification and adjustments to maximize the Doppler signal strength, the probe was mechanically locked during the monitoring. The changes of blood flow velocity of the left middle cerebral artery(MCA) induced by cognitive demands were monitored. The measurement of the meal flow velocities(MFV) of MCA were made while the subjects were prior to, during, and after ERP. We recorded the MFVs during ERP. Statistical analysis was performed using t-tests with SPSS-PC for windows release 6.0. Results : All subjects showed a relative increase in MFV of MCA during the task. The mean rise was about 3.2-4.2%(p <0.05). Although TCD does not measure absolute values of regional cerebral blood flow(rCBF) or absolute rCBF changes, changes of flow velocity can reflect relative rCBF changes. Conclusions : The generation site of P300 still remains unclear but the neocortical, thalamic and limbic region and temporal-parietal cortex have been proposed. The MCA supplies these anatomical structures. The Changes of flow veolocity of MCA during the ERP test suggest that the some part of the brain fed y the MCA activate of the temporal lobe or parietal lobes, we can deduce that some parts of brain fed by the MCA participate in the generation of P300.

• Journal of the Korean Electrochemical Society
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• v.12 no.4
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• pp.329-334
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• 2009

This study is to develop a fuel cell system applicable to an in situ NMR (Nuclear magnetic resonance) diagnosis. The in situ NMR can be used in real time monitoring of various reactions occurring in the fuel cell, such as oxidation of fuel, reduction of oxygen, transport phenomena, and component degradation. The fuel cell for this purpose is, however, to be operated in a specifically designed tubular shape toroid cavity detector (TCD), which constrains the fuel cell to have a tubular shape. This may cause difficulties in effective mass transport of reactants/products and uniform distribution of assembly pressure. Therefore, a new flow field designed in a particular way is necessary to enhance the mass transport in the tubular fuel cell. In this study, a tubular-shaped close-type flow field made of non-magnetic material is developed. With this flow field, oxygen is effectively delivered to the cathode surface and the produced water is readily removed from the membrane-electrode assembly to prevent flooding. The resulting DMFC (direct methanol fuel cell) outperforms the open-type flow field and exhibits $36\;mW/cm^2$ even at room temperature.

• The Journal of Internal Korean Medicine
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• v.25 no.3
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• pp.418-426
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• 2004

Objectives : This study was designed to research whether transcranial doppler ultrasound(TCD) can yield a suitable diagnosis or prognosis for dizziness. Methods : To evaluate the blood flow, we measured the mean velocity(Vm), peak systolic velocity(Vs) and pulsatility index(PI) of the middle cerebral artery(MCA), vertebral artery(VA) and basilar artery(BA) in 54 dizziness patients and 44 normal subjects. To investigate the difference between dizziness patients and normal subjects, we selected 54 dizziness patients diagnosed normal by Brain MRI, and 44 normal subjects who did not have any symptoms of hyperlipemia, hypertension, diabetes melitus, heart disease, or smoking, diagnosed normal by Brain MRI. 30-69 year olds were divided into 30-49 year olds, 50-59 year olds and 60-69 year olds. Results : In normal subjects, there was a significantly higher Vm, Vs in the MCA and BA, and Vs in the VA of female subjects, and there was a significant difference in PI in the MCA and BA increasing with age. In comparison with normal subjects, dizziness patients had a significantly lower Vm in the BA. Male dizziness patients had significantly lower PI in the MCA. 30-49 year olds had significantly lower Vm in the BA. Conclusions : The significant difference in blood flow velocities in the BA between dizziness patients and normal subjects suggests that dizziness is related to blocking of blood flow in the BA and that diagnosis and prognosis can be made through TCD. More detailed study of dizziness patients will be needed.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.349-359
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• 2000

The aim of study was to evaluated the possible role of cranial artery velocity in headache pathogenesis. The present study was studied of five headache(F=5. Mean $age=29.80\pm6.76yrs$) were compared to 4 controls(F=4, Mean $age=29.00\pm5.48yrs$). Transcranial doppler ultrasonography(TCD) is a new non-invasive and easily applicable method to evaluate flow velocities of the intracranial and extracranial cerebral arteries. TCD was performed with standard method to measure the mean Flow Velocity(MFV) of the middle and posterior cerebral arteries, the internal carotid artery, the vertebral and the basilar artery. We reviewed the whole TCD results performed at Taejon Veterans Hospital from October. 11. 2000 to November. 10. 2000. Mean flow velocities in headaches and controls at their 6 decades are $28.00\pm3.61cm/sec$ and $41.25pm1.71cm/sec$ in lent PCA (P<0.01), $50,000\pm23.07cm/sec$ and $82.75\pm15.59cm/sec$ in right MCA(P<0.05), $26.20\pm4.82cm/sec$ and $45.50\pm4.51cm/sec$ in fight PCA(P<0.01). $26.60\pm4.56cm/sec$ and $38.25\pm4.92cm/sec$ in right VAC(P<0.01). After treatment for 2 weeks, mean of velocity on pre treatment and post treatment and post treatment are $28.00\pm3.61cm/sec$ and $38.20\pm5.81cm/sec$ in left PCA (P<0.05), $26.20\pm4.827cm/sec$ and $39.20\pm5.54cm/sec$ in right PCA(P<0.05), $40.60\pm9.18cm/sec$ in right VA(P<0.01). It is concluded that Electrical Therapy for two weeks was effected to promote Mean Flow of Velocity in cranial artery. Mean of velocity in cranial artery with headaches observed in this study was lower than controls, but MFV was promote after treatment for 2 weeks.

• 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.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.126-135
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• 2018

This study examined whether the difference in the middle cerebral artery (MCA) velocities can predict the prognosis of stroke and whether the prognostic impact differs among stroke subtypes. Transient ischemic attack (TIA) or acute ischemic stroke patients, who underwent a routine evaluation and transcranial Doppler (TCD), were included in this study. The MCA asymmetry index was calculated using the relative percentage difference in the mean flow velocity (MFV) between the left and right MCA: (|RMCA MFV-LMCA MFV|/mean MCA MFV)${\times}100$. The stroke subtypes were determined using the TOAST classification. Poor functional outcomes were defined as a mRS score ${\geq}3$ at 3 months after the onset of stroke. A total of 988 patients were included, of whom 157 (15.9%) had a poor functional outcome. Multivariable analysis showed that only the MCA asymmetry index was independently associated with a poor functional outcome. ROC curve analysis showed that adding the MCA asymmetry index to the prediction model improved the discrimination of a poor functional outcome from acute ischemic stroke (from 88.6% [95% CI, 85.2~91.9] to 89.2% [95% CI, 85.9~92.5]). The MCA asymmetry index has an independent prognostic value for predicting a poor short-term functional outcome after an acute cerebral infarction. Therefore, TCD may be useful for predicting a poor functional outcome in patients with acute ischemic stroke.

• Biomedical Science Letters
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• v.25 no.4
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• pp.381-389
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• 2019

The physiological function test is the only patient contact area in the field of clinical laboratory. We need to recruit and encourage the experts due to requiring the expertise and long time for examination. However, there is currently no rule for estimating optimal workforce in the field of physiological function tests. The purpose of this study is to establish the basis of the studies for mid- to long-long term job creation in the field of ultrasound by evaluating the number of appropriate tests and appropriate workforce. We calculated the quantitative and qualitative workload for the number of appropriate tests and appropriate workforce using online questionnaire. All statistical analyses were performed using SPSS version 18.0 (SPSS Inc., Chicago, IL, USA). A total of 216 respondents were 48 (22.2%) male and 168 (77.8%) female. A total of 157 laboratories were 62 (39.5%) for echocardiography, 91 (58.0%) for the transcranial Doppler (TCD) and 4 (5.7%) for the carotid ultrasound. The mean number of appropriate tests was 10 ± 2 in the echocardiography, 9 ± 2 in TCD and 11 ± 2 in the carotid ultrasound. In addition, the number of laboratories required to recruit employees for appropriate workforce was 19 in echocardiography, 18 in TCD, and 0 in carotid ultrasound. The number of hospital required to recruit workforce were 7 primary hospitals, 22 secondary hospitals, 7 third hospitals. This study can be used as an important data as the first study at present time when the data on the workforce status and work environment of the ultrasonic laboratories is insufficient. Based on the quantitative and qualitative workloads, the number of appropriate tests and appropriate workforce can support mid- to long-long term job creation in the field of ultrasound.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.245-250
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• 2007

Adsorption characteristics of 1,2-dichlorobenzene on the surface of heat treated silica gel were determined by the moment analysis. The heat treatment of the silica gel was performed at temperatures of 150, 500, and $800^{\circ}C$ and pulse-response of 1,2-dichlorobenzene was measured in a gas chromatograph equipped with thermal conductivity detector (TCD) using the packed column. Equilibrium adsorption constants and isosteric heat of adsorption were recorded the highest value at $500^{\circ}C$. This might be due to the increase of interaction between silica surface and 1,2-dichlorobenzene as the decrease of OH concentration and moisture by increase of heating temperature. Axial dispersion coefficient calculated by the moment method was about $0.046{\times}10^{-4}{\sim}1.033{\times}10^{-4}m^2/sec$ and pore diffusivity of heat treated silica gel at $500^{\circ}C$ measured the lowest value. Because heat treating at $800^{\circ}C$ caused the specific surface area to reduce, equilibrium adsorption constants and isosteric heat of adsorption were decreased.

• Journal of Korean Neurosurgical Society
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• v.40 no.6
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• pp.434-440
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• 2006

Objective : The purpose of this study is to examine the influence of cranioplasty on dynamics of cerebral blood flow[CBF] and cerebrovascular reserve capacity[CVRC], and to investigate the usefulness of single photon emission computed tomography [SPECT] as a prognostic factor for neurological improvement after cranioplasty. Methods : Between March 2003 and December 2005, a prospective study was performed on 24 patients who had undergone total 25 cranioplasty operations. Cerebral blood flow velocities in the middle cerebral artery[MCA] and internal carotid artery[ICA] were obtained by transcranial Doppler ultrasonography[TCD]. The CVRC was assessed by SPECT in the natural state and after stimulation with 1g of acetazolamide. Neurological improvement after cranioplasty was compared between patients who showed hyperactivity to acetazolamide-activated SPECT [Group 1, n=7] and hypoactivity to acetazolamide-activated SPECT [Group 2, n=17]. These measurements were obtained two weeks prior to and two weeks after cranioplasty. Results : The blood flow velocities at the opposite site to the cranioplasty as well as at the cranioplasty site were significantly increased [P<0.05]. Compared with Group 2, there was significant increase in CBF and neurological improvement after cranioplasty in Group 1. Conclusion : Among patients with surgical bony defects, the patients who had normal reactivity of the CVRC showed a significant increase in CBF and neurological improvement after cranioplasty. The authors suggest that CVRC measurement prior to surgery may be an important prognostic factor for neurological improvement after cranioplasty.