• Title, Summary, Keyword: resistive index

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The Measurement of Blood Flow of Anterior Cerebral Artery in Premature Newborns Using Duplex Doppler Ultrasonography (이중 초음파 검사를 이용한 미숙아의 전 뇌동맥 혈류 측정)

  • Hwang, Mi-Soo;Bae, Kyeung-Kug;Lee, Jae-Kyo
    • Yeungnam University Journal of Medicine
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    • v.14 no.1
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    • pp.77-84
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    • 1997
  • We measured the blood flow velocity of the anterior cerebral artery via anterior fontanelle approach of fifty five preterm neonates with duplex Doppler sonography and analyzed the waveform and calculated pulsatility index, resistive index. Intracranial velocities and pulsatility indexes were increased with increasing gestational age, birth weight, and age of the neonate, but resistive indices decreased. In sick babies, characteristic resistive index increment were seen in patients with intraventricular hemorrhage, but no statistical difference was seen in patients with respiratory distress syndrome. Our results suggest that duplex Doppler sonography is a useful noninvasive means of monitoring cerebrohemodynamics in normal preterm neonates and flow change of sick babies.

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Ultrasonographic Resistive Index of the Interlobar Renal Artery in Renal Failure Induced by Ochratoxin A and Citrinin Toxicosis in Dogs (Ochratoxin-A 및 Citrinin 중독 신부전 개에서 신장엽간동맥 혈관저항지수에 대한 도플러초음파 평가)

  • Bae, Jun-Woo;Seong, Yun-Sang;Oh, Tae-Ho;Jang, Kwang-Ho;Lee, Keun-Woo;Eom, Ki-Dong
    • Journal of Veterinary Clinics
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    • v.23 no.4
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    • pp.427-431
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    • 2006
  • Pulse Doppler ultrasonographic evaluation was performed to investigate the resistive index (RI) of the Interlobar renal artery in 17 dogs (32 kidneys) which were diagnosed with an acute renal failure caused by ochratoxin-A and citrinin contaminated commercial diet. RI was investigated in 7 normal beagle dogs and recovered patients. The mean of RI was resulted as $0.69{\pm}0.04$ in normal dog, however, significantly (p<0.001) increased as $0.76{\pm}0.05$ in renal failure dog. But RI had no relationship with the results of blood chemistry, urine analysis, and excretory urographic image quality. From these results, even though the results of the renal function test were within a normal reference range, it was considered that RI index is more reliable to represent a damaged renal parenchyma, and may have the potential to be a useful clinical tool in monitoring of the renal function.

The Effects of Regular Resistive Exercise on Cardiopulmonary Ability and Cerebral Blood Flow Velocity (규칙적인 저항 운동이 심폐 능력과 뇌혈류 속도에 미치는 영향)

  • Yu, Jae-Ho;Lee, Suk-Min
    • Journal of the Korean Society of Physical Medicine
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    • v.5 no.2
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    • pp.255-264
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    • 2010
  • Purpose : The purpose of this study is to analysis effects of resistive exercise on cardiopulmonary fitness and cerebral artery blood flow velocity. Methods : Ten healthy university students had done resistive exercise without aerobic exercise over one year participated resistive exercise group and ten general university students, then were calculated oxygen consumption ($VO_2$) and respiratory exchange rate($VO_2/VCO_2$). After a week, they were measured Transcranial Doppler Ultrasonography(TCD) at moderate exercise(HRmax 50%), maximal exercise (HRmax 100%) for taking cerebral blood flow velocity. Results : In the comparison between groups, resistive exercise group showed significant higher oxygen consumption and lower respiratory exchange than controls(p<0.05). In resistive exercise group, oxygen consumption was significant negative correlation with cerebral artery pulsatory index(p<0.05). but, oxygen consumption was significant positive correlation with systolic blood flow velocity in controls(p<0.05). Conclusions : After considering all the factors, important value in resistive exercise is regular participation and help us increasing contingency response ability.

Effects of anesthetics on resistive index of the medial long posterior ciliary artery and ophthalmic artery using color doppler imaging

  • Choi, Ho-jung;Lee, Young-won;Yoon, Jung-hee;Yeon, Seong-chan;Lee, Hyo-jong;Lee, Hee-chun
    • Korean Journal of Veterinary Research
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    • v.45 no.3
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    • pp.423-427
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    • 2005
  • Color Doppler imaging (CDI) was carried out to evaluate the anesthetics effect on ophthalmic circulation using CDI-derived resistive index (RI) values. CDI was preformed on 24 dogs, and RI values were calculated for the medial long posterior ciliary artery (mLPCA) and ophthalmic artery (OA) before and after administration of anesthetics. After administration of benoxinate or acepromazine, a significant change of the mLPCA RI was not found. But, a significant decrease of the RI following ketamine (p < 0.001) or xylazine (p < 0.01) administration could be observed as compared with the self-control. Mean RI value of OA also showed this same trend. Intraocular pressure was significantly decrease following benoxinate (p < 0.01), acepromazine (p < 0.01), and xylazine (p < 0.001) administration within normal range. The results suggest that some anesthetics influence on ophthalmic vascular resistance. Therefore, chemical restraint was carefully used in clinical application of CDI-derived RI measurement. Particularly, benoxinate and acepromazine is useful chemical restraint without a change of the ophthalmic vascular resistance.

Ultrasonographic Resistive Index of the Cranial Pancreaticoduodenal Artery in Normal Conscious Dogs (정상견에서 전방 췌장십이장 동맥의 초음파학적 혈관 저항지수)

  • Eom, Ki-Dong;Lee, Hae-oon;Seong, Yun-sang;Lee, Jeong-min;Lee, Jong-won;Oh, Tae-ho
    • Journal of Veterinary Clinics
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    • v.20 no.3
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    • pp.274-277
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    • 2003
  • The purpose of this study was to determine the range of resistive index(RI) of the cranial pancreaticoduodenal artery(cPDA) in the normal dog's and to assess the possibility of clinical application of RI for diagnosing a pancreatitis. Five patients with acute pancreatitis and 17 healthy adult beagle dogs were used. Duplex color Doppler ultrasonographic examination was performed by using a real-time scanner with 11-MHz linear-array transducer. The dogs were restrained in dorsal recumbency without the use of chemical agent. The mean RI of the normal pancreas(0.63$\pm$0.04) was significantly(t = 5.79, p = 0.001) different from acute pancreatitis dog(0.75$\pm$0.04). Duplex color Doppler ultrasonography was an useful technique for detecting and measuring RI of the cPDA. The evaluation of RI of the cPDA may be a valuable supportive diagnostic procedure for evaluating the pancreatitis or suspected in dogs.

Relation between Quality and Current Noise in Carbon Film Resistors (탄소피막고정저항기의 품질과 전류잡음과의 관계)

  • 노홍조
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.9 no.5
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    • pp.34-42
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    • 1972
  • Current noise is an important indication of quality in deposited carbon film resistors. Imperfections in the resistive film create high current densities and consequently high current noise. The magnitude of current noise is depend upon many inherent properties of the resistor such as resistive material and others such as processing, fabrication and packing of resistive elements, etc. Performance tests have definitely established a correlation between current noise and electrical performance of carbon film resistors. To interprete the normal distribution of the current noise index for representative groups of resistors would serve as a powerful tool in judging the Quality control and product uniformity by the manufacturer.

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Evaluation of Resistive Index Using Color Doppler Imaging in Canine Ophthalmic Vasculature (개의 안혈관에 대한 컬러도플러초음파를 사용한 저항지수의 평가)

  • Lee, Hee-Chun;Yoon, Jung-Hee
    • Journal of Veterinary Clinics
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    • v.20 no.2
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    • pp.145-149
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    • 2003
  • Color Doppler imaging(CDI) was carried out to determine CDI-derived resistive index(RI) values of normal canine ophthalmic vasculature and its reproducibility. CDI was performed on 58 dogs. and normal ranges of RI value were calculated for the medial long posterior ciliary artery(mLPCA), ciliary artery(CA), and ophthalmic artery(OA). Ophthalmic vascular RI values of normal dogs were 0.67$\pm$0.07, 0.70$\pm$0.06, and 0.80$\pm$0.04 in mLPCA, CA, and OA, respectively. Means of RT value of all vessel had no statistically significant difference by sex, fellow orbits, and skull type. The results suggest that color Doppler imaging is a noninvasive test which has the advantage of providing objective measurements of blood flow velocity parameter in the canine eye and orbit.

Effect of anesthetics and diuretics on Doppler measurements of intrarenal resistive index in dogs

  • Choi, Ho-jung;Yoon, Jung-hee;Eom, Ki-dong;Lee, Hee-chon;Choi, Ji-hye;Sung, Jae-ki
    • Korean Journal of Veterinary Research
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    • v.39 no.4
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    • pp.832-837
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    • 1999
  • lntrarenal resistive index (RI) was determined in normal, sedated and diuretic kidneys. The mean RI values of normal dogs were $0.64{\pm}0.03$ without statistically significant difference between left and right kidney. Interrenal RI difference (${\Delta}RI$) was $0.03{\pm}0.01$. No significant relationship was found between mean intrarenal RI versus body weight. The mean intrarenal RI values after administration of acepromazine, xylazine, thiopental, and ketamine were $0.66{\pm}0.03$, $0.64{\pm}0.03$, $0.56{\pm}0.05$, and $0.50{\pm}0.05$, respectively. After administration of acepromazine or xylazine, a significant change of the RI was not found. But, a significant decrease of the RI following thiopental or ketamine administration could be observed as compared with the normal RI. The mean intrarenal RI values were $0.63{\pm}0.06$ and $0.62{\pm}0.04$ at 10 minutes and 30 minutes after injection of furosemide, respectively. No significant change of intrarenal RI was found after administration of furosemide. But, mannitol significantly decreased mean intrarenal RI to $0.57{\pm}0.02$ and $0.58{\pm}0.03$ at 30 minutes and 60 minutes, respectively. Based on the obtained results, values of 0.72 and 0.05 may be proposed as the reasonable upper limits of RI and ${\Delta}RI$ of normal average. Acepromazine or xylazine are recommended as anesthetics for renal diseases because they have less effect on the RI. Further study using mannitol injection to increase ${\Delta}RI$ may be suggested in unilateral urinary tract obstruction since mannitol more effectively changed mean RI than furosemide.

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Current Limiting Characteristics according to Applied Voltage Increase of Resistive-type SFCL using YBCO Coated Conductor (YBCO Coated Conductor를 이용한 저항형 전류제한기의 인가전압 증가에 따른 전류제한 특성)

  • Du, Ho-Ik;Kim, Min-Ju;Doo, Seung-Gyu;Kim, Yong-Jin;Lee, Dong-Hyeok;Han, Byoung-Sung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.10
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    • pp.854-859
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    • 2009
  • The YBCO coated conductor is an important element that forms the superconducting power equipment. The first advantage of applying YBCO coated conductor to superconducting power equipment is that it can effectively addresses the normal and fault currents using less quantity of wire than when using Bi tape due to its high critical current density. Second, it can limit the fault current fast because its index value is high. so that the resistance can be produced fast when it is applied to the superconducting current limiting element. Third, the type of stabilization layer that surrounds the YBCO superconductor is selectable and the magnitude of the resistance that is produced from quenching can be adjusted. This study researched into the manufacture of current-limiting element of using YBCO coated conductor, into the characteristics of current limiter that considered by combining the manufactured element with the resistive-type superconducting fault current limiter.

Improving the Reliability by Straight Channel of As2Se3-based Resistive Random Access Memory (As2Se3 기반 Resistive Random Access Memory의 채널 직선화를 통한 신뢰성 향상)

  • Nam, Ki-Hyun;Kim, Chung-Hyeok
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.6
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    • pp.327-331
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    • 2016
  • Resistive random access memory (ReRAM) of metallic conduction channel mechanism is based on the electrochemical control of metal in solid electrolyte thin film. Amorphous chalcogenide materials have the solid electrolyte characteristic and optical reactivity at the same time. The optical reactivity has been used to improve the memory switching characteristics of the amorphous $As_2Se_3$-based ReRAM. This study focuses on the formation of holographic lattices patterns in the amorphous $As_2Se_3$ thin film for straight conductive channel. The optical parameters of amorphous $As_2Se_3$ thin film which is a refractive index and extinction coefficient was taken by n&k thin film analyzer. He-Cd laser (wavelength: 325 nm) was selected based on these basic optical parameters. The straighten conduction channel was formed by holographic lithography method using He-Cd laser.$ Ag^+$ ions that photo-diffused periodically by holographic lithography method will be the role of straight channel patterns. The fabricated ReRAM operated more less voltage and indicated better reliability.