• Annals of Clinical Neurophysiology
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• 제20권2호
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• pp.79-84
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• 2018

Background: Pulsatility of cerebral arteries and aortic stiffness have been associated with white matter hyperintensities (WMH). We explored which is better correlated with the severity of WMH in a population with acute lacunar infarct. Methods: We included patients with acute small subcortical infarcts who underwent transcranial Doppler (TCD) and brachial ankle pulse wave velocity (baPWV). Exclusion criteria were any stenosis or occlusion on major cerebral arteries on magnetic resonance angiography; poor temporal insonation windows; ankle brachial index < 0.9; and atrial fibrillation. We assessed the performance of the pulsatility index of bilateral middle cerebral arteries (PI-MCA) and baPWV for predicting moderate-to-severe WMH, defined as an Age Related White Matter Changes score > 5, and then sought to find independent predictors using binary logistic regression analysis. Results: Eighty-three patients (56 males, mean age $61.5{\pm}11.4$) participated in the study. Uni-variate analysis showed old age and high PI-MCA were significantly correlated with moderate-to-severe WMH. However, baPWV was not associated with the severity of WMH. Multivariate analysis revealed old age (odds ratio per 1-year increase, 1.068; p = 0.044) and upper tertile of PI-MCA (odds ratio, 5.138; p = 0.049) were independently associated with moderate-to-severe WMH. Receiver-operating characteristics showed PI-MCA differentiated those with and without moderate-to-severe WMH with an area under the curve of 0.719. Conclusions: PI-MCA derived from TCD was better correlated with the severity of WMH than baPWV in a population with lacunar infarction. Pulsatility of cerebral arteries may better predict cerebral small vessel disease than the aortic stiffness index.

• 대한환경공학회지
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• 제37권3호
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• pp.175-181
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• 2015

이산화탄소 포집을 위한 기능성 흡착제인 폴리에틸렌이민(PEI)을 함침한 활성탄을 평가하였다. 이산화탄소 흡착제의 흡착 특성은 GC/TCD, BET 표면적 및 FT-IR을 사용하였다. 활성탄에 PEI를 10, 30, 50 wt%를 함침하여 흡착제를 합성하고, 온도변화에 따른 이산화탄소의 흡착능을 조사하였다. $20^{\circ}C$와 $100^{\circ}C$에서의 이산화탄소 흡착능은 다음과 같다: $20^{\circ}C$에서는 AC > PEI(10)-AC > PEI(30)-AC > PEI(50)-AC의 순으로 나타났으며, $100^{\circ}C$에서는 PEI(10)-AC > PEI(30)-AC > PEI(50)-AC > AC 순으로 나타났다. 아민 기능기의 활성탄의 흡착능이 순수 활성탄보다 아미노기에 의하여 화학 흡착 때문에 높은 온도에서 높게 나타났다. 본 연구의 결과로 PEI(10) 활성탄은 고온의 가스로부터 이산화탄소 포집에 가장 유능한 흡착제 중 하나로 보여진다.

• 분석과학
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• 제12권6호
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• pp.490-497
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• 1999

불활성기체용융-열전도도 측정법의 수소분석기를 개조하여 글로브박스에 설치했으며 조사핵연료피복관의 수소분석에 사용했다. Zr과 Ti 매질의 수소표준물질로 용융조제인 주석을 사용하지 않고도 수소함량 $3{\mu}g$까지 분석가능하였다. 시료의 크기가 작을수록 수소 회수율이 높았으며 지르칼로이 시료의 수소분석시 Ti 매질의 표준물질을 사용할 수 있음을 확인하였다. 수소분석에 사용한 실제 조사핵연료피복관의 평균 방사능은 10 mR/hr였으며 평균수소농도는 130 ppm이었다.

• 대한환경공학회지
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• 제33권9호
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• pp.686-691
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• 2011

본 연구는 MEA가 함침된 MCM-41에 대하여 이산화탄소 흡착실험과 특성 분석을 하였다. 흡착제의 XRD, FT-IR, $N_2$흡탈착 실험을 통하여 물리적 특성을 분석하였으며, 흡착실험은 15%의 이산화탄소를 사용하여 GC-TCD를 통하여 분석하였다. MEA 함침량이 10~40 wt%까지 함침량이 증가할수록 이산화탄소 흡착능은 증가하였다. 그러나 MEA 함침량이 50 wt%에서 흡착능이 감소하였다. 많은 아민이 제공되면 흡착제 표면에서 제공된 아민이 변형되는 경향이 있다. 그러므로 이산화탄소 흡착능이 감소될 수 있다. 본 연구의 결과로 이산화탄소 흡착을 위한 MCM-41에 MEA의 함침 함량의 조절이 중요하다는 것으로 사료되어진다.

• 대한의생명과학회지
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• 제10권4호
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• pp.467-472
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• 2004

Transcranial Doppler sonography (TCD) is a useful diagnostic method to measure cerebral blood flow velocity in various cerebral disorders. However, we haven't data enough to be available for young persons, especially in the twenties in Korea. This study was performed to collect the basic data of the cerebral blood flow velocity and to understand the cerebral physiology in the twenties. We determined the mean velocities of middle, anterior, and posterior cerebral artery, and vertebral and basilar artery (MCA-V, ACA-V, PCA-V, VA-V, and BA-V, respectively) in eighty-two healthy volunteers. For evaluating cerebral autoregulation, only the MCA- V was measured under various conditions such as stable, apnea, and hyperventilation state. Right and left MCA-V were 80.66±14.03 and 83.22±14.40 cm/sec at stable state, 90.13±17.47 and 90.26±16.38 cm/sec at apnea, and 54.83±11.09 and 55.33±10.74 cm/sec at hyperventilation. Right and left ACA-V were 49.11±15.71 and 48.19±13.75 cm/sec. Right and left PCA-V were 39.44±9.12 and 37.91±6.74 cm/sec. Right and left VA-V were 33.65±9.26 and 36.l8±10.39 cm/sec. BA-V was 48.49±11.16 cm/sec. Right and left MCA- V, V A-V, and right ACA- V and PCA- V in women were higher than those of men (P<0.05). No significant differences were found between men and women in the others. These findings indicate that cerebral hemodynamics and autoregulation were normal in young people in their twenties. The velocities of MCA, ACA, PCA, and BA were high values in women as compared with men.

• 국제물리치료학회지
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• 제2권1호
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• pp.251-259
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• 2011

The aim of this is to examine the effects of SSP therapy on the internal carotid arteries blood flow of 24 tension type headache patients(study group) and non tension type headache patients(control group), and on the reduction of their headaches, when applied to the acupuncture points. It stimulated the acupuncture point of headache 6 place with the SSP. It measured VAS and the blood flow of the internal carotid arteries with TCD. When the internal carotid arteries blood flow of study group and control group were compared by period, a significant difference was found in the 4th period(p<.05). When the Visual Analog Scale of study group and control group were compared by period, a significant difference was found in the 4th period(p<.05). The comparison of each measurement result of the internal carotid arteries blood flow of the study group found significantly increased. The comparison of each measurement result of the VAS of study group found significantly decreased. With regard to the control group, the VAS significantly decreased. The silver spike point low frequency electrical stimulation treatment, when applied to the acupuncture point, can significantly influence the internal carotid arteries blood flow of headache patients and can significantly reduce their headaches.

• 공업화학
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• 제28권2호
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• pp.257-262
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• 2017

본 연구에서는 electrospinning method의 공정변수를 다르게 하여 CNF (carbon nanofiber)를 제조하였다. 제조된 CNF의 섬유의 형태, 직경 등의 변화를 SEM 분석을 통해 관찰하였으며 인가전압, TCD (tip to collecor distance), 고분자 용액의 농도, 열처리 단계가 CNF 물성을 형성함에 있어 주요한 영향인자임을 확인하였다. 또한 서로 다른 물성으로 제조된 CNF를 전기분해 공정의 전극으로 적용하여 toluene의 제거 효율을 비교하였고, 이를 통해 anode 뿐만 아니라 cathode 역시 전기분해 효율에 직접적인 영향을 미침을 확인하였다.

• 대한한방내과학회지
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• 제19권1호
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• pp.157-167
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• 1998

Background and Purpose : Cerebrovascular reactivity(CVR) can be estimated by measuring the change of cerebral blood flow that occurs during vasostimulation. To estimate the cerebrovascular reactivity, we investigated the change of flow velocity of the middle cerebral artery(MCA) during hyperventilation and hypoventilation with the transcranial doppler. So we studied whether the CVR measured by this method could show a significant difference between the normal and the cerebral infarction subjects and whether the CVR may decrease with age in normal subjects. Methods : Using transcranial doppler, we measured the mean velocity(Vm), the pulsatility index(P.I.) at the resting state, the end of breath-holding and the end of hyperventilation in 36 normal and 10 cerebral infarction subjects, so we calculated the percentile change of mean velocity(%${\Delta}$Vm) and P.I.(%${\Delta}$P.I.) after the vasostimulation. We estimated the change of Vm, P.I., %${\Delta}$Vm and %${\Delta}$P.I. by the age group and compared those parameters between the age-matched normal control and cerebral infarction subjects. Results : The Vm in MCA significantly decreased with age(p<0.05), but there was no significant difference in Vm and P.I. between normal and cerebral infarction subjects. The %${\Delta}$Vm and %${\Delta}$P.I. in response to hyperventilation significantly decreased with age in MCA and there was significant difference in $%{\Delta}Vm$ of MCA after breath-holding between the normal and cerebral infarction subjects. Conclusion : The breath-holding and hyperventilation tests could be non-invasive and useful methods in estimation of the cerebrovascular reactivity and could be applied in the basal and follow-up evaluation of the cerebrovascular reserve of the ischemic stroke patients.

• 동의신경정신과학회지
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• 제20권1호
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• pp.199-214
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• 2009

Objectives : This study was performed to change of blood flow in In-Young(ST9) after treatment on chronic daily headache patients. Methods : Monitoring of TCD was examined in 10' s chronic daily headache patients before and after treatment. Mean velocity flow, systolic velocity and pulsatility index were analyzed from TCD at In-Young(ST9). The patients was laid for 20 minutes before treatment and also for treatment. Results : The results showed a significant(p<0.05: Paired T-test) decrease in mean velocity flow and systolic velocity. but there were no significant differences in pulsatility index. Conclusions : These results suggest that there were significant change on blood flow in In-young of chronic daily headache patients.

• 한국안전학회지
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• 제26권2호
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• pp.42-47
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• 2011

Going underwater is supposed to begin with the history of human beings. At first it was confined to relatively shallow level, less than several meters by holding breath. Recently, deep level diving has been necessary for such purpose as construction, maritime salvage, military operations, research and sports by using SCUBA(self-contained underwater breathing apparatus) equipment. As one goes down into water, the pressure on the diver is increased due to water pressure with depth, usually 1 atm for each 10 m water level. In deep water, mixed gas or nitrox(EAN, enriched air nitrox) could be applied for the divers lest they should get disease due to high pressure. Of these, the former is usually composed of oxygen and inert gas like helium or hydrogen, the latter contains higher oxygen content than that in normal air in which the oxygen concentration is designated by the character "EAN" followed by vol. % of oxygen, for example, "EAN 40" contains 40% of oxygen. In this case, a victim was found at the 39 m below the sea surface breathing air and nitrox in cylinder wrongly marked as EAN 36, which was analyzed to contain 63% of oxygen by GC/TCD. The cause of death could not be exactly related with the oxygen content in the nitrox cylinder, because the accurate depth for the victim to dive was not known, even though the victim was just found at the depth of 39 m. However, the wrongly marked nitrox could be believed to be the main cause of the death at the depth unless there happened any other accident except that during diving.