The Experts below are selected from a list of 2052 Experts worldwide ranked by ideXlab platform

Renshi Sawada - One of the best experts on this subject based on the ideXlab platform.

  • detection of site specific Blood flow variation in humans during running by a wearable laser doppler Flowmeter
    Sensors, 2015
    Co-Authors: Wataru Iwasaki, Hirofumi Nogami, Satoshi Takeuchi, Eiji Higurashi, Masutaka Furue, Renshi Sawada
    Abstract:

    Wearable wireless physiological sensors are helpful for monitoring and maintaining human health. Blood flow contains abundant physiological information but it is hard to measure Blood flow during exercise using conventional Blood Flowmeters because of their size, weight, and use of optic fibers. To resolve these disadvantages, we previously developed a micro integrated laser Doppler Blood Flowmeter using microelectromechanical systems technology. This micro Blood Flowmeter is wearable and capable of stable measurement signals even during movement. Therefore, we attempted to measure skin Blood flow at the forehead, fingertip, and earlobe of seven young men while running as a pilot experiment to extend the utility of the micro Blood Flowmeter. We measured Blood flow in each subject at velocities of 6, 8, and 10 km/h. We succeeded in obtaining stable measurements of Blood flow, with few motion artifacts, using the micro Blood Flowmeter, and the pulse wave signal and motion artifacts were clearly separated by conducting frequency analysis. Furthermore, the results showed that the extent of the changes in Blood flow depended on the intensity of exercise as well as previous work with an ergometer. Thus, we demonstrated the capability of this wearable Blood flow sensor for measurement during exercise.

  • Comparable Accuracy of Micro-Electromechanical Blood Flowmetry-Based Analysis vs. Electrocardiography-Based Analysis in Evaluating Heart Rate Variability
    Circulation journal : official journal of the Japanese Circulation Society, 2015
    Co-Authors: Terukazu Akiyama, Hirofumi Nogami, Eiji Higurashi, Tatsuya Miyazaki, Hiroki Ito, Shin Ichi Ando, Renshi Sawada
    Abstract:

    BACKGROUND Because the conventional evaluation of autonomic nervous system (ANS) function inevitably uses long-lasting uncomfortable electrocardiogram (ECG) recording, a more simplified and comfortable analysis system has been sought for this purpose. The feasibility of using a portable micro-electromechanical system (MEMS) Blood Flowmeter to analyze heart rate variability (HRV) for evaluating ANS function was thus examined. METHODS AND RESULTS Measurements of the R-R interval (TRR) derived from an ECG, simultaneously with the pulse wave interval (TPP) derived from a MEMS Blood Flowmeter, in 8 healthy subjects was performed and resultant HRV variables in time and frequency domains were compared. The TRR- and TPP-derived variables were strongly correlated (coefficients of regression for low frequency (LF), high frequency (HF), and LF/HF of 1.1, 0.66, and 0.35, respectively; corresponding coefficients of determination of 0.92, 0.63, and 0.91, respectively (P

  • influence of alcohol consumption on Blood flow as detected using a micro integrated laser doppler Blood Flowmeter
    2010 First International Conference on Sensor Device Technologies and Applications, 2010
    Co-Authors: Wataru Iwasaki, Renshi Sawada, Hirofumi Nogami, Satoshi Takeuchi, Masutaka Furue, Yoshinori Kimura, Atsushi Onoe, Hiroki Ito, Eiji Higurashi
    Abstract:

    Using microelectromechanical systems technology, the authors have developed the world’s smallest, lightest and lowest electric power-consuming laser Doppler Blood flow sensor that can measure Blood flow while the subject is moving. The influence of alcohol consumption on Blood flow was investigated when measuring at a subject’s earlobe. An arm-raising test in which the subject lifts an arm with the Blood flow sensor attached to a fingertip was also investigated. This arm-raising test can’t be conducted with a commercial instrument that uses an optical fiber because the measurement is easily affected by the movement of the fiber. Good correlation between Blood flow at an earlobe, heart rate and breath alcohol content was obtained for light consumers of alcohol. Also, the influence of acetaldehyde on the Blood flow was found in the arm-raising test for all subjects using the developed Blood flow sensor.

  • integrated laser doppler Blood Flowmeter designed to enable wafer level packaging
    IEEE Transactions on Biomedical Engineering, 2010
    Co-Authors: Yoshinori Kimura, Eiji Higurashi, M Goma, Atsushi Onoe, Renshi Sawada
    Abstract:

    The authors propose a new sensor structure for an integrated laser Doppler Blood Flowmeter that consists of two silicon cavities with a PD and laser diode inside each cavity. A silicon lid formed with a converging microlens completes the package. This structure, which was achieved using micromachining techniques, features reduced optical power loss in the sensor, resulting in its small size and significantly low power consumption. Measurements using a model tissue Blood flow system confirmed that the new sensor had high linearity and a wide dynamic range for measuring tissue Blood flow.

  • low power consumption integrated laser doppler Blood Flowmeter with a built in silicon microlens
    International Conference on Optical MEMS and Nanophotonics, 2008
    Co-Authors: Yoshinori Kimura, Eiji Higurashi, Atsushi Onoe, Renshi Sawada
    Abstract:

    We propose a new structure for the integrated laser Doppler Blood Flowmeter which consists of a Si cavity and a photodiode and a laser diode within the cavity. A silicon cover formed with a converging microlens also functions as the package. This structure has a reduced rate of optical power loss in the sensor, resulting in significantly low power consumption.

Yilmaz Savaş - One of the best experts on this subject based on the ideXlab platform.

Kenichi Sugihara - One of the best experts on this subject based on the ideXlab platform.

  • assessment of intestinal viability using a non contact laser tissue Blood Flowmeter
    American Journal of Surgery, 2000
    Co-Authors: Masayuki Ando, Masashi Ito, Zenro Nihei, Kenichi Sugihara
    Abstract:

    Background: Intraoperative assessment of small intestinal viability following ischemic insult from arterial occlusion has remained difficult. The purpose of the present study was to assess the applicability of non-contact tissue Blood Flowmeter (NCLBF) with regard to intraoperative assessment of intestinal viability. Methods: Using the ischemia-reperfusion model of rabbits, the relationship between the records of NCLBF, pulse oximetry (PO), and histological grade and the comparison of accuracy of intestinal viability among NCLBF, PO, and fluorescein (FL) were examined. Results: There was a significant relationship between NCLBF and the histological grade (coefficient-0.80, P <0.0001); however, PO was not related. The accuracy and sensitivity of bowel viability of NCLBF (76%, 88%) were better than those of PO (58%, 23%) and FL (48%, 4%), respectively (P <0.001). Conclusions: NCLBF is useful to assess intestinal viability, suggesting the possibility of clinical use.

  • Assessment of intestinal viability using a non-contact laser tissue Blood Flowmeter.
    American journal of surgery, 2000
    Co-Authors: Masayuki Ando, Masashi Ito, Zenro Nihei, Kenichi Sugihara
    Abstract:

    Background: Intraoperative assessment of small intestinal viability following ischemic insult from arterial occlusion has remained difficult. The purpose of the present study was to assess the applicability of non-contact tissue Blood Flowmeter (NCLBF) with regard to intraoperative assessment of intestinal viability. Methods: Using the ischemia-reperfusion model of rabbits, the relationship between the records of NCLBF, pulse oximetry (PO), and histological grade and the comparison of accuracy of intestinal viability among NCLBF, PO, and fluorescein (FL) were examined. Results: There was a significant relationship between NCLBF and the histological grade (coefficient-0.80, P

Eduardo Tavares Costa - One of the best experts on this subject based on the ideXlab platform.

  • ultrasonic pulsed doppler Blood Flowmeter for use in extracorporeal circulation
    Artificial Organs, 2000
    Co-Authors: Ricardo G Dantas, Eduardo Tavares Costa
    Abstract:

    : In cardiac surgeries, it is frequently necessary to make the external Blood circulation and oxygenation artificially. This procedure is called extracorporeal circulation (EC) or heart-lung bypass. During EC, one of the most important parameters, which demands continuous monitoring, is the Blood flow. In many cases, the Blood flow is estimated by the pump velocity (in roller pumps) or measured with transducers based on electromagnetic methods (in centrifugal pumps). This article presents an ultrasonic Doppler Blood Flowmeter to be used in the arterial line of an extracorporeal circulation system. The ultrasonic probe is coupled to a half-inch tube connector of the extracorporeal arterial line, is not disposable, and does not need sterilization. The developed Flowmeter revealed itself to be efficient and reliable and can be inserted in a closed-loop pump controller system or be used as stand-alone equipment.

Inan Güler - One of the best experts on this subject based on the ideXlab platform.