스마트 헬스케어를 위한 자계용적맥파 기반 혈압 추정에 관한 연구

이성수(Seong-Su Lee),이강휘(Kang-Hwi Lee),김상민(Sang-Min Kim),이혁재(Hyeok-Jae Lee),이병헌(Byoung-Hun Lee),김경섭(Kyeong-Seop Kim),이정환(Jeong-whan Lee) 대한전기학회 2018 전기학회논문지 Vol.67 No.7

High blood pressure causes various cardiovascular diseases and is associated with mortality. Periodic selfmonitoring and recording of blood pressure is very helpful in preventing the occurrence of secondary diseases caused by hypertension. However, existing cuff-type blood pressure monitors have many limitations. As an alternative of that, a method of estimating the blood pressure by measuring the velocity change of the blood flow using the photo plethysmography is widely known. However, photo plethysmography have a low correlation with blood flow. So, we will propose an algorithm for estimating blood pressure using the relationship between velocity change of blood flow measured by magnetic field instead of photo plethysmography and electrocardiogram. For this purpose, First, we analyzed the correlation between photo plethysmography and magneto plethysmography. the correlation between MPG and PPG was r = 0.9449. Second, we compared estimated blood pressure and measured blood pressure. In the four experiment each result was r = 0.5737, r = 0.7863, r = 0.5669, and r = 0.7445.

유체의 성질에 따른 자계용적맥파의 검출 특성에 관한 연구

김상민(Sang-Min Kim),이강휘(Kang-Hwi Lee),이성수(Seong-Su Lee),이혁재(Hyeok-Jae Lee),이병헌(Byoung-Hun Lee),김경섭(Kyeong-Seop Kim),이정환(Jeong-whan Lee) 대한전기학회 2018 전기학회논문지 Vol.67 No.7

Photo-plethysmography (PPG), which measures changes in the peripheral blood flow of a human body using difference in absorption rate of light, is a measurement method that is studied and used in clinical and various applications due to its simple circuit configuration and measurement convenience. Magneto-plethysmography (MPG), which is newly developed by our team, is a method of measuring changes in the conductivity of biological tissues by using a eddy current induced by a time-varying magnetic field, and is not subject to optical interference. In this study, we investigated the detection characteristics of MPG according to the change of the conductivity of the object and fluid to be measured by simultaneously measuring PPG and MPG. In order to control the speed of fluid known in advance, a blood flow simulator was implemented and used. The fluid used in the experiment was general mineral water and physiological saline (0.9% NaCl) solution. Experimental results show that the amplitude change of the measured PPG was 0.3% in normal water and saline solution, and that of MPG was 77.3%. Therefore, it is considered that the magneto-plethysmography (MPG) has a strong correlation with the conductivity of the fluid.

오픈 하드웨어 플랫폼 기반 착용형 뇌파측정 시스템의 구현

김상민(Sang-min Kim),이강휘(Kang-Hwi Lee),이성수(Sung-Su Lee),이혁재(Hyeok-Jae Lee),이병헌(Byoung-Hun Lee),이주현(Ju-Hyeon Lee),김동준(Dong-Jun Kim),이정환(Jeong-Whan Lee) 대한전기학회 2018 대한전기학회 학술대회 논문집 Vol.2018 No.-

Effective Dose Equivalent due to Inhalation of Indoor Radon-222 Daughters in Korea

장시영,하정우,이병헌,Chang, Si-Young,Ha, Chung-Woo,Lee, Byoung-Hun Korean Association for Radiation Protection 1991 방사선방어학회지 Vol.16 No.1

국내 12개 지역의 340여 실내에서 측정한 라돈농도로부터 단순한 수학적 폐선량 평가모형을 이용하여 주민의 실효선량당량을 평가하였다. 수동적 시간적분형 CR-39 라돈컵으로 1990년 4월부터 10월까지 $3{\sim}4$개월 동안 측정 한 실내의 라돈농도는 지역별로 $33.82{\sim}61.42 Bq/m^3$(평균 : $48.90 Bq/m^3$)의 분포를 보였으며, 이로 인한 라돈자핵종의 평형등가라 돈농도$(EEC_{Rn})$는 라돈과 자핵종간의 평형인자의 값 0.4를 적용했을 때 $13.53{\sim}24.57Bq/m^3$(평균 : $19.55 Bq/m^3$)으로 예상되었다. 국제방사선방어위원회의 폐모형에 근거한 본 연구의 폐선량 평가모형에서 유도된 단위 평형등가라돈농도의 피폭당 실효선량당량환산 인자는 $1.07{\times}10^{-5}\;mSv/Bq\;h\;m^{-3}$으로 국제방사선방어위원회나 국제연합 방사선영향평가 과학위원회(UNSCEAR)에서 권고한 값과 잘 일치하였다. 동 선량환산인자와 CR-39 라돈 컵으로 측정 한 실내 의 평균 평형등가라돈농도를 년간 $0.75 m^3/h$의 호흡율로 호흡한 것으로 가정했을 때, 주민이 받는 년평균 폐선량당량 및 실효선량당량은 갹각 20.90 mSv 및 1.25 mSv인 것으로 평가되었다. 동 피폭선량은 국제연합(UNSCEAR)에서 1988년에 발표한 일반인의 년평균 자연방사선피폭 실효선량당량인 2.40mSv의 거의 50%에 상당하였다. Effective dose equivalents resulting from inhalation of indoor radon-222 daughters at 12 residential areas in Korea were assessed by a simple mathematical lung dosimetry model based on the measurements of long-term averaged radon concentrations at 340 dwellings. The long-term averaged indoor radon-222 concentrations and corresponding eqilibrium equivalent radon $concentration(EEC_{Rn})$ measured by passive time-integrating CR-39 radon cups are in the range of $33.82{\sim}61.42Bq/m^3(median\;:\;48.90Bq/m^3)$ and of $13.53{\sim}24.57Bq/m^3(median\;:\;19.55Bq/m^3)$, respectively. The effective dose equvalent conversion factor for the exposure to unit $EEC_{Rn}$ derived in this study was estimated $1.07{\times}10^{-5}mSv/Bq\;h\;m^{-3}$ for a reference adult and agreed well with those recommended by the ICRP and UNSCEAR. The annual average dose equivalent to the lung $(H_{LUNG})$ from inhalation exposure to measured $EEC_{Rn}$ was estimated to be 20.90 mSv and resulting effective dose $equivalent(H_E)$ was to be 1.25 mSv, which is about 50% of the natural radiation exposure of 2.40 mSv/y to the public reported by the UNSCEAR.

Effect of Gamma Radiation on the Callus Initiation and Organogenesis on Tissue Cultivation of Nicotiana tabaccum L.

Sun Hee Shin(신선희),Byoung Hun Lee(이병헌),Hi Sup Song(송희섭),Jin Kyu Kim(김진규) 한국생물공학회 2004 한국생물공학회 학술대회 Vol.2004 No.4

감마선 이용 AEMA 도입 PCL 나노섬유의 제조 및 특성분석

서다은(Da-Eun Seo),정성린(Sung In Jeong),박종석(Jong-Seok Park),권희정(Hui-Jeong Gwon),안성준(Sung-Jun An),이병헌(Byoung Hun Lee),임돈순(Don-Sun Im),신흥수(Heungsoo Shin),임윤묵(Youn-Mook Lim) 한국고분자학회 2017 폴리머 Vol.41 No.1

폴리카프로락톤(polycaprolactone, PCL)은 생체적합성이 우수하고 시간이 지나면 체내에서 생분해되어 조직공학용 생체재료로 많이 사용되고 있다. 하지만, 소수성 표면과 낮은 세포 부착성을 나타내는 단점이 있다. 따라서 본 연구에서는 PCL 필름 및 전기방사를 통한 나노섬유 지지체를 제조하고 감마선을 이용하여 친수성과 양전하의 아민기를 갖는 2-아미노에틸메타크릴레이트(2-aminoethylmethacrylate, AEMA)로 표면을 개질하였다. 감마선을 이용하여 표면 개질된 PCL 필름과 나노섬유의 분석 결과, ATR-FTIR을 통해 감마선 선량과 반응 표면적이 증가할수록 표면의 아민기가 증가함을 확인하였다. 아민기의 증가로 인해 친수성이 증가했음을 확인하였고 단백질 흡착량이 정전기적 인력으로 인해 증가함을 확인하였다. 이를 통해 AEMA가 도입된 PCL 필름보다 나노섬유 지지체의 경우 세포적합성이 향상된 조직공학용 지지체로서의 응용 가능성이 매우 높을 것으로 기대된다. Polycaprolactone (PCL) has been applied to tissue engineering because it has excellent biocompatibility and biodegradable properties. However, there is a limit to hydrophobic surface and low cell adhesion, therefore the PCL requires surface modification for increasing hydrophilicity and cell adhesion capacity. In this study, PCL films and nanofibers were manufactured by solvent casting and electrospinning, respectively. They were modified by 2-aminoethylmethacrylate (AEMA) that had hydrophilicity and amine groups of positive charge using gamma-irradiation. The surface properties of AEMA-grafted PCL films and nanofibers were confirmed by ATR-FTIR, and amine groups were increased by surface area and gamma-irradiation dose. A significantly higher amount of negative-charged proteins adhered to hydrophilic and cationic surface of AEMA-grafted PCL nanofibers than that of AEMA-grafted PCL films, because of increased amine groups and electrostatic interaction. The results show that AEMA-grafted PCL nanofibers are possible to apply tissue engineering scaffolds.

0.25% Bupivacaine/Fentanyl 과 0.125% Bupivacaine/Fentanyl 의 간헐적 경막외강 주입이 분만에 미치는 영향

이은미,양우창,정미화,원임수,이병헌 대한마취과학회 1998 Korean Journal of Anesthesiology Vol.35 No.3

Background : Conventional intermittent $quot;Top-up$quot; injections (CIT) of fentanyl added to bupivacaine reduces the total amount of local anesthetic required, resulting in less motor blockade, reducing incidence of instrumental deliveries, and improving the quality of analgesia during labor. The purpose of this study was to compare the analgesic efficacy of two different solutions and side effects of them. Methods : Fifty healthy parturients were divided into two groups: intermittent epidural injections of 0.25% bupivacaine with 0.0005% fentanyl (Group I) and 0.125% bupivacaine with 0.0005% fentanyl (5 g/ml) (Group II). We injected 5 ml of each solution to block T10 sensory level of the request of the parturients. Assessments included interval of epidural injection, duration of first and second stage of labor, total dose of bupivacaine, maternal blood pressure, satisfaction, fetal heart rate, and Apgar scores. Results : The interval of epidural injection was 75.7 50.6 min in Group I, compare with 57.8 27.5 min in Group II (p<0.05). The total dose of bupivacaine was 45.5 15.3 mg in Group I, compared with 23.5 10.4 mg in Group II (p<0.05). There was no significant difference between the two groups in terms of duration of labor, maternal blood pressure, maternal satisfaction, fetal heart abnormality, or Apgar scores of neonates. No serious side effects were encountered in either group, although two patients in Group I experienced urinary retention. Only one patient in each group experienced nausea and vomiting. Conclusions : The injection of 0.125% bupivacaine plus fentanyl provides good analgesia during labor. We concluded that lower concentration of bupivacaine was better in consideration of adverse effects of it on fetus and mother. (Korean J Anesthesiol 1998; 35: 467∼472)

단시간 수술시 단독 지속주입 정맥 마취제로서의 Propofol 마취와 Fentanyl 마취의 비교

이은미,양우창,정미화,원임수,이병헌,박지애 대한마취과학회 1998 Korean Journal of Anesthesiology Vol.34 No.4

Background: Propofol, a new intravenous anesthetic agent, is now used for brief operation and day surgery for its rapid recovery and controllability. Propofol, rapid acting sedatives hypnotics, is known to no analgesic effect. This study was taken to evaluate the analgesic effect of propofol, compared to those of fentanyl. Methods : Forty patients(ASA physical status 1, 2) scheduled for surgery of short duration(within 1 hour) were randomly allocated into two groups. Induction of anesthesia was performed by injection of thiopental(5 mg/kg) and succinylcholine(1 mg/kg) and ventilated with O2-N2O(50%) after endotracheal intubation. Maintenance of anesthesia was performed by vecuronium(1 mg/kg) and continuous infusion of propofol(group I) or fentanyl(group II). Results : There was no significant differences in systolic and diastolic blood pressure in both groups. In heart rate, there was significant difference at preincision and postincision between two groups. Time to extubation(4.5 4.6 vs 6.3 4.6 min), time to eye open(7.5 7.1 vs 6.6 5.4 min), time to complain pain after stop dropping at recovery room(30.5 8.0 vs 35.5 17.9 min), the average flow rate of drugs (6.0 2.2 mg/kg/hr vs 6.7 2.4 g/kg/hr) has no significant difference between two groups. Conclusions: A single continuous infusion of propofol is applied as one of general anesthesia methods with O2-N2O, muscle relaxants. Propofol has a appropriate and similar analgesic effect compared with fentanyl in operation of little hemodynamic changes and short operation, and rapid recovery compared with fentanyl. (Korean J Anesthesiol 1998; 34: 751∼757)

Effective Dose Equivalent due to Inhalation if Indoor Radon-222 Daughters in Korea

Chang, Si-Young,Ha, Chung-Woo,Lee, Byoung-Hun 대한방사선 방어학회 1991 방사선방어학회지 Vol.16 No.1

국내 12개 지역의 340여 실내에서 측정한 라돈농도로부터 단순한 수학적 폐선량 평가모형을 이용하여 주민의 실효선량당량을 평가하였다. 수동적 시간적분형 CR-39 라돈컵으로 1990년 4월부터 10월까지 3∼4개월 동안 측정한 실내의 라돈농도는 지역별로 33.82∼61.42Bq/㎥(평균 : 48.90 Bq/㎥)의 분포를 보였으며, 이로 인한 라돈자핵종의 평형등가라돈농도(??)는 라돈과 자핵종간의 평형인자의 값 0.4를 적용했을 때 13.53∼24.57 Bq/㎥(평균 : 19.55 Bq/㎥)으로 예상되었다. 국제방사선방어위원회의 페모형에 근거한 본 연구의 폐선량 평가모형에서 유도된 단위 평형등가라돈농도의 피폭당 실효선량당량환산인자는 ?? 국제방사선방어위원회나 국제연합 방사선영향평가과학위원회(UNSCEAR)에서 권고한 값고 잘 일치하였다. 동 선량환산인자와 CR-39 라돈컵으로 측정한 실내의 평균 평형등가라돈농도를 년간 0.75㎥/h의 호흡율로 호흡한 것으로 가정했을 때, 주민이 받는 년평균 폐선량당량 및 실효선량당량은 각각 20.90 mSv 및 1.25 mSv인 것으로 평가되었다. 동 피폭선량은 국제연합(UNSCEAR)에서 1988년에 발표한 일반인의 년평균 자연방사선피폭 실효선량당량인 2.40mSv 의 거의 50%에 상당하였다. Effective dose equivalents resulting from inhalation of indoor radon-222 daughters at 12 residential areas in Korea were assessed by a simple mathematical lung dosimetry model based on the measurements of long-term averaged radon concentrations at 340 dwellings. The long-term averaged indoor radon-222 concentrations and corresponding eqilibrium equivalent radon concentration(??) measured by passive time-integrating CR-39 radon cups are in the range of 33.82∼61.42 Bq/㎥(median : 48.90 Bq/㎥) and of 13.53∼24.57 Bq/㎥(median : 19.55 Bq/㎥), respectively. The effective dose equivalent conversion factor for the exposure to unit ?? derived in this study was estimated ?? for a reference adult and agreed well with those recommended by the ICRP and UNSCEAR. The annual average dose equivalent to the lung (??) form inhalation exposure to measured ?? was estimated to be 20.90 mSv and resulting effective dose equivalent(??) was to be 1.25 mSv, which is about 50% of the natural radiation exposure of 2.40 mSv/y to the public reported by the UNSCEAR.