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임피던스법을 이용한 혈압 및 혈류 변화량 검출 시스템 구현
노정훈(Ro, Jung-Hoon),배진우(Bae, Jin-Woo),예수영(Ye, Soo-Young),신범주(Shin, Bum-Joo),전계록(Jeon, Gye-Rok) 한국산학기술학회 2009 한국산학기술학회논문지 Vol.10 No.8
본 연구에서는 혈압 측정 시 생체 임피던스가 변화하는 현상을 이용하여 혈류량 변화를 검출하는 시스템을 구현하였다. 혈압의 측정은 오실로메트릭법을 적용하였으며, MAA 알고리즘을 이용하여 평균 동맥압을 산출한 후 평 균 동맥압에 대한 여러 가지 특성비율을 설정하여 수축기 및 이완기 혈압을 추정하였다. 인체 임피던스 측정은 교류 정전류원과 락인-증폭기를 이용하였으며, 측정 부위에 인가되는 커프 압력에 의해 생체 임피던스 변화량을 이용하여 혈류량 변화를 측정하였다. In this study, detection system of the blood flow variation rate was implemented using the variation effect of bio electric impedance at time of the blood pressure measurement by means of impedance method. The blood pressure measurement was performed by the oscillometric method. The mean arterial pressure was calculated using maximum amplitude algorithm. The systolic and diastolic pressure were estimated by establishment of the various characteristic ratio according to mean arterial pressure range. Alternative static current source and lock_in amplifier were introduced to impedance measurement. The variation of blood volume was measured using variation bio impedance according to induced cuff pressure at measuring area.
노정훈 ( Jung Hoon Ro ),전계록 ( Gye Rok Jeon ),박태용 ( Tae Yong Park ),김성식 ( Sung Sik Kim ),김진범 ( Jin Bom Kim ),김지영 ( Ji Young Kim ) 대한예방치과·구강보건학회 2009 大韓口腔保健學會誌 Vol.33 No.3
Objective: The purpose of this study was to find out the optimal wavelength of turnable lasers for selective ablation of surface enamel caries. Methods: The absorption spectra of the sound tooth and caries lesion were measured. A figure of merit was defined as the ratio of the two. The trend was verified by direct measurement of the onset threshold of laser power of the sound and decayed area. Results: Optimal wavelength range for selective removal of caries from the sound tissue with turnable wavelength laser was estimated to be between 500-600 nm from the reflectance spectrum measurement of sound teeth and caries. Direct measured plasma onset power of laser beam corresponded to the same spectral range. In the sound tooth, about 20 J/cm2 irradiation power with 8 ns pulse of 532 nm laser beam was measured for plasma generation while that of caries lesion was about 12 J/cm2 as expected from the figure of merit by reflection spectrum measurement. Conclusion: The optimal spectral range for laser ablation of dental caries is between 500 nm to 600 nm both from optical absorption and onset plasma generation power measurement. The figure of merit defined as the ratio of threshold power of laser ablation is bigger than 1.4 in this range.
김지민,신성찬,권현근,천용일,노정훈,이병주,Kim, Ji Min,Shin, Sung-Chan,Kwon, Hyun-Keun,Cheon, Yong-Il,Ro, Jung Hoon,Lee, Byung-Joo 대한후두음성언어의학회 2021 대한후두음성언어의학회지 Vol.32 No.1
Background and Objectives During speech, the vocal folds oscillate at frequencies ranging from 100-200 Hz with amplitudes of a few millimeters. Mechanical stimulation is an essential factor which affects metabolism of human vocal folds. The effect of mechanical vibration on the cellular response in the human vocal fold fibroblasts cells (hVFFs) was evaluated. Materials and Method We created a culture systemic device capable of generating vibratory stimulations at human phonation frequencies. To establish optimal cell culture condition, cellular proliferation and viability assay was examined. Quantitative real time polymerase chain reaction was used to assess extracellular matrix (ECM) related and growth factors expression on response to changes in vibratory frequency and amplitude. Western blot was used to investigate ECM and inflammation-related transcription factor activation and its related cellular signaling transduction pathway. Results The cell viability was stable with vibratory stimulation within 24 h. A statistically significant increase of ECM genes (collagen type I alpha 1 and collagen type I alpha 2) and growth factor [transforming growth factor β1 (TGF-β1) and fibroblast growth factor 1 (FGF-1)] observe under the experimental conditions. Vibratory stimulation induced transcriptional activation of NF-κB by phosphorylation of p65 subunit through cellular Mitogen-activated protein kinases activation by extracellular signal regulated kinase and p38 mitogen-activated protein kinases (MAPKs) phosphorylation on hVFFs. Conclusion This study confirmed enhancing synthesis of collagen, TGF-β1 and FGF was testified by vibratory stimulation on hVFFs. This mechanism is thought to be due to the activation of NF-κB and MAPKs. Taken together, these results demonstrate that vibratory bioreactor may be a suitable alternative to hVFFs for studying vocal folds cellular response to vibratory vocalization.
유주연,박근철,전아영,김윤진,노정훈,전계록,Yoo, Ju-Yeon,Park, Guen-Chul,Jeon, Ah-Young,Kim, Yun-Jin,Ro, Jung-Hoon,Jeon, Gye-Rok 대한의용생체공학회 2011 의공학회지 Vol.32 No.2
In this study, the system for application of the bone stimulation was implemented using high frequency and low strain method. The whole system consists of the high frequency and low strain vibration stimulation system 177 for stimulating bone, LVDT sensor, and wireless sensor based on tri-axial accelerometer. To evaluate the usefulness of the system, the frequencies and accelerations from function generator were applied to the vibration stimulation system. The range of frequency was 17 Hz, 30 Hz, 45 Hz, 50 Hz and the range of acceleration was set 0.3 g, 0.6 g, 1g, and 2 g. The measured frequencies and acceleration using LVDT (linear variable difference transformer) sensor and 3-axial accelerometer were estimated and compared. The range of frequencies average difference was from 0.0 to 0.004 Hz. As the standard deviation of frequencies estimated by LVDT sensor and accelerometer was below 0.03 Hz and the output frequencies of function generator were similar: Also the results of t-test were satisfied with conditions of p > 0.05. And the acquired frequencies and acceleration from vibration measuring device module were estimated and analyzed. As the mean of accelerations was similar to the acceleration applied from function generator. And the standard deviation of acceleration estimated from vibration measuring device module was ranged from 0.019 g to 0.038 g. Also the results of t-test were satisfied with conditions of p > 0.05. Therefore, these results were airy similar to the acceleration applied from function generator. As a result, the usefulness of the system was confirmed. n a further study, clinical experiment will be carried out with the authorization of IRB (institutional review board) so that appropriate frequency and strain would be investigated in clinical field.
전완 골절 후 도수 정복 시 골절 부위 간격에 따른 골절 인접 연부 조직의 생체역학적 특성 평가: 유한요소해석
박준성,이상현,송찬희,노정훈,이치승,Park, Jun-Sung,Lee, Sang Hyun,Song, Chanhee,Ro, Jung Hoon,Lee, Chiseung 대한의용생체공학회 2022 의공학회지 Vol.43 No.5
The purpose of this study is to evaluate the biomechanical properties of fractured adjacent soft tissue during closed reduction after forearm fracture using the finite element method. To accomplish this, a finite element (FE) model of the forearm including soft tissue was constructed, and the material properties reported in previous studies were implemented. Based on this, nine finite element models with different fracture types and fracture positions, which are the main parameters, were subjected to finite element analysis under the same load and boundary conditions. The load condition simulated the traction of increasing the fracture site spacing from 0.4 mm to 1.6 mm at intervals of 0.4 mm at the distal end of the radioulnar bone. Through the finite element analysis, the fracture type, fracture location, and displacement were compared and analyzed for the fracture site spacing of the fractured portion and the maximum equivalent stress of the soft tissues adjacent to the fracture(interosseous membrane, muscle, fat, and skin). The results of this study are as follows. The effect of the major parameters on the fracture site spacing of the fractured part is negligible. Also, from the displacement of 1.2 mm, the maximum equivalent stress of the interosseous membrane and muscle adjacent to the fractured bone exceeds the ultimate tensile strength of the material. In addition, it was confirmed that the maximum equivalent stresses of soft tissues(fat, skin) were different in size but similar in trend. As a result, this study was able to numerically confirm the damage to the adjacent soft tissue due to the fracture site spacing during closed reduction of forearm fracture.
이재우,권순복,이병주,이진춘,고의경,전경명,왕수건,노정훈,Lee, Jae-Woo,Kwon, Soon-Bok,Lee, Byung-Joo,Lee, Jin-Choon,Goh, Eui-Kyung,Chon, Kyong-Myong,Wang, Soo-Geun,Ro, Jung-Hoon 대한후두음성언어의학회 2006 대한후두음성언어의학회지 Vol.17 No.1
Purpose: Evaluation of vocal cord vibration is very important in cases of voice disorders. There are several equipments for examining the vocal fold vibration such as laryngeal stroboscope, ultra high-speed digital imaging system, and videokymograph. Among these, laryngeal stroboscope is the most popular equipment because of easy to examine the laryngeal pathology. However, current laryngo-stroboscopes are too bulky to move and relatively expensive. The purpose of this research is to develope a portable laryngeal stroboscope of equivalent performance with the current equipments. Methods and Materials: Recently developed high luminescent white LEDs(light emitting diodes) are placed at the head of the endoscope as light sources for the CCD image sensor which is also placed at the head with imaging lens. This arrangement eliminates the bulky light source like expensive halogen or xenon lamps as well as the optical light guiding cables. The LEDs are controlled to flash in phase with the voice frequency of the examinee. The CCD captures these strobo images and converts them into video signals for examinations. Results: There was no functional differences between preexisting stroboscope and the newly developed stroboscope of this study. LED light sources and microprocessor based control circuits of the stroboscope enabled the development of flicker-less, hand-held, portable and battery-operating stroboscope. Conclusion: The developed stroboscope is cost-effective, small-sized, easy to use and very easy desirable to bring and to use in any place.
워그너_빌 분포 변환 기법을 이용한 마취단계별 심박변이율 신호 분석
전계록,김명철,유주연,이해림,박성민,손정만,예수영,노정훈,김길중,백승완,Jeon, Gye-Rok,Kim, Myung-Chul,Yoo, Ju-Yeon,Lee, Hae-Lim,Park, Seong-Min,Shon, Jung-Man,Ye, Soo-Young,Ro, Jung-Hoon,Kim, Gil-Jung,Baik, Seung-Wan 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.2
In this study, the heart rate variability(HRV) signal of operating patient was acquired according to anesthesia progress and identified to evaluation possibility of depth of anesthesia in each anesthesia stage. The HRV signal was analyzed time-frequency domain applied to Wigner-Ville distribution method, the characteristic parameters were extracted for evaluation of depth of anesthesia in each anesthesia stage. The progress of general anesthesia was divided into the states of pre-operation, induction of anesthesia, operation, awaking and post-operation.