저자는 그들의 지원에 대 한 국가 핵심 기술 연구 및 과학과 기술의 중국 (No. 2011BAK15B06)의 개발 프로그램을 감사합니다. 슈 야 주앙 어 비디오 촬영을 완료 하는 데 도움에 대 한 우리의 실험실에서 마스터 학생입니다 감사 합니다.

1. 물 스 트라이 더 다리에 표면 구조 관찰
<ol><li>낚시 방문 그물을 사용 하 여 로컬 민물 연못에서 물 소금을 수집 합니다.</li>
	<li>가 위를 사용 하 여 실험 샘플으로 적어도 5 쌍의 중간 다리를 잘라. 표면 오염 및 미세 다리 앞의 방해를 방지 하기 위해 신중 하 게, 다리의 바닥을 터치 합니다.</li>
	<li>공중에서 다리를 자연스럽 게 건조.</li>
	<li>그림 1는에서 같이 마이크로 수준의 해상도 스캐닝 전자 현미경을 사용 하 여 다리의 표면 미세 관찰.</li>
	<li>그림 1b와 같이 나노 수준의 해상도 스캐닝 전자 현미경을 사용 하 여 다리의 microsetae를 관찰 합니다.</li>
</ol>2. 준비 동적 힘 측정 시스템의 구성 요소
<ol><li>14.9 X 10.2 m m2 X 28 μ m, 10 개 이상의 생산의 차원 PVDF 필름 센서를 구입 마이크로 스트레인 당 mV. 참고: PVDF 필름 센서는 높은 감도와 동적 접촉 힘을 감지 하는 데 사용 됩니다.</li>
	<li>최대 1000 mV/pC 충전 이득 충전 앰프를 구입 하 고 낮은 소음 미만 5 μV. 참고: 충전 앰프는 변환기에서 충전 출력은 전압으로 변환할 PVDF 필름 센서에서 신호를 확대 하는 데 사용 됩니다.</li>
	<li>데이터 수집 장치, 아날로그 입력 범위는 1에서에서 샘플 속도가지고 있는 구매 102.4 kS/s s/s. 참고: 데이터 수집 디바이스는 충전 앰프의 전압 데이터 추가 처리를 위해 컴퓨터에 보내 고 표시 하는 데 사용 됩니다.</li>
	<li>몇몇 높은 정밀 변위 단계와는 전동기를 구입. 참고: 다리는 전동기에 의해 구동 하는 서로 다른 속도에서 물에서 출발 합니다.</li>
	<li>구입 CCD 카메라, 초점 길이가 5 m m 30 m m 및 프레임 속도 범위에는 30 프레임입니다. 참고:이 카메라는 기록 하 고 수 면과 다리와 물 표면 사이의 거리의 변형 모니터링 사용 됩니다.</li>
	<li>고성능 컴퓨터를 준비 합니다.</li>
</ol>3. 동적 힘 측정 시스템의 모든 부품의 조립
<ol><li>그림 2a 와b 그림 2표시 된 실제 실험 악기 회로도 그림에 따라 동적 힘 측정 시스템을 조립.</li>
	<li>다른 쪽은 매달려 서 수평 프레임에 배치 됩니다 높은 정밀 변위 단계로 전극을 가진 PVDF 필름 센서의 한쪽을 수정 합니다. PVDF 필름 센서의 설치 방법이 동적 마이크로 힘에 대 한 측정의 해상도 향상 시킬 수 있습니다.</li>
	<li>충전 앰프, 데이터 수집 디바이스와 컴퓨터를 데이터 수집 디바이스를 충전 앰프에 PVDF 필름 센서를 연결 합니다.</li>
	<li>PVDF 필름 센서의 왼쪽에 배치 됩니다 높은 정밀 변위 단계로 카메라를 수정 합니다.</li>
	<li>약 다리와 물 사이의 거리를 신속 하 게 조정, PVDF 필름 센서 위에 프레임 높은 정밀 변위 무대를 수정, PVDF 필름 센서에서 그 분리 약 10 ㎝ 이다.</li>
	<li>정확한 속도로 물 표면에서 다리를 들어, 높은 정확한 변위 무대 아래 보조 전동기를 수정.</li>
</ol>4. 동적 힘 측정 시스템의 교정
<ol><li>정전기 힘 시스템26 를 사용 하 여 누구의 크기 미만 0.5 µN. 내부 및 외부 전극에 적용 된 전압에 의해 시스템의 정전기 힘을 제어 해야 하는 PVDF 필름 센서의 자유로운 끝에 행동 하는 마이크로 상수 강제로 생성 뛰어난된 원통형 축전기. 주의: 힘 PVDF 필름 표면에 수직한 방향으로 행동 해야 하 고 응용 프로그램의 포인트 감도 높이기 위해 PVDF 필름 센서의 끝에 가능한 한 가까이 있어야 하는데.</li>
	<li>단계 입력을 생성 하기 위해 짧은 시간에 힘을 놓습니다.</li>
	<li>수 읽기 PVDF 필름 센서의 출력 전압 신호 LabVIEW 소프트웨어를 사용 하 여 컴퓨터에서 4.2 단계의 전압-시간 신호를 읽어.<ol>
<li>LabVIEW 소프트웨어 및 Ni-daqmx에는 공식 웹사이트의 내쇼날인스트루먼트 하드웨어 드라이버를 다운로드 합니다.</li>
		<li>표시 된 그림 3는 LabVIEW를 사용 하 여 연속 아날로그 전압 측정의 데모를 엽니다.</li>
		<li>채널 설정의 모듈에 충전 앰프와 연결 된 데이터 수집 디바이스의 물리적 채널을 선택 합니다.</li>
		<li>100000 100000 타이밍설정 모듈에서 샘플의 수와 샘플링 속도 설정 합니다.</li>
		<li>로깅 모드는 로그 및 읽기를 선택 하 고 로깅 설정의 모듈에 전압 데이터를 저장 파일 경로 작성.</li>
		<li>트리거설정 모듈에서 아무 트리거 를 선택 합니다.</li>
		<li>전압 신호를 샘플링 하려면 도구 모음에서 화살표 모양의 버튼을 클릭 합니다.</li>
	</ol>
</li>
	<li>있는 피크 전압은 해당 강제 하는 센서에 행동 전압 곡선을 분석 합니다.</li>
	<li>다른 힘 입력, 전압-포스 포인트의 시리즈 얻었다은에서 4.1-4.4 단계 반복 합니다.</li>
	<li>피크 출력 전압 및 교정 결과에 표준 힘에 대 한 관계를 결정 합니다.</li>
</ol>5. 특정 속도로 접착 힘의 측정
<ol><li>사용 하 여 기계적 micropipette PVDF 필름 센서의 자유로운 끝에 물방울 (5 µ L)를 배치 합니다. 참고: 위치는 물방울의 PVDF 필름 센서의 끝에 가까이 있어야 한다.</li>
	<li>높은 정밀 변위 무대 아래 보조 전동기를 단 하나 다리를 스틱.</li>
	<li>그림 4는에서 같이 높은 정밀 변위 무대 아래로 다리 연락처 물 표면까지 이동 합니다. 센서의 왼쪽된 측면에 장착 된 카메라 시스템에 의해 다리와 물 표면 사이의 거리를 모니터링 합니다.</li>
	<li>전동기를 통해 일정 한 속도로 물 표면에서 다리를 들어올립니다.</li>
	<li>4.6, 단계에서 설립 하는 모델을 사용 하 여 출발 프로세스의 전압 곡선의 각 지점에 해당 하는 힘을 계산 하 고 그림 4b와 같이 과정, 출발의 힘-시간 곡선을 그립니다.</li>
	<li>특정 속도에서 출발 과정의 피크 접착을 기록 합니다.</li>
</ol>6. 다른 속도로 접착 힘의 측량.
<ol><li>전동기에 의해 다리의 운동 속도 변경 하 고 5 단계에 따라 접착 힘을 측정 한다.</li>
	<li>6.1 단계에서 얻은 데이터를 사용 하 여 속도 곡선을 해제 대 접착 힘을 플롯 합니다.</li>
	<li>접착 힘 및 곡선을 통해 리프팅 속도 사이의 관계를 분석 합니다.</li>
</ol>

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Y., Xu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+flexible+piezoelectric+force+sensor+based+on+PVDF+fabrics.">A flexible piezoelectric force sensor based on PVDF fabrics.</a> Smart Materials and Structures. 20 (4), 045009 (2011).</li><li>Liu, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+PVDF+film+to+stress+measurement+of+structural+member.">Application of PVDF film to stress measurement of structural member.</a> Journal of the Society of Naval Architects of Japan. 2002 (192), 591-599 (2002).</li><li>Fujii, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proposal+for+a+step+response+evaluation+method+for+force+transducers.">Proposal for a step response evaluation method for force transducers.</a> Measurement Science and Technology. 14 (10), 1741-1746 (2003).</li><li>Zheng, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+environmental+noise+suppression+for+micronewton+force+sensing+based+on+electrostatic+by+injecting+air+damping.">Improving environmental noise suppression for micronewton force sensing based on electrostatic by injecting air damping.</a> Review of Scientific Instruments. 85 (5), 055002 (2014).</li><li>Zheng, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+multi-position+calibration+of+the+stiffness+for+atomic-force+microscope+cantilevers+based+on+vibration.">The multi-position calibration of the stiffness for atomic-force microscope cantilevers based on vibration.</a> Measurement Science and Technology. 26 (5), 055001 (2015).</li><li>Sun, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Differential+Method+for+Force+Measurement+Based+on+Electrostatic+Force.">The Differential Method for Force Measurement Based on Electrostatic Force.</a> Journal of Sensors. 2017, 1857920 (2017).</li><li>Song, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+Sensitive,+Precise,+and+Traceable+Measurement+of+Force.">Highly Sensitive, Precise, and Traceable Measurement of Force.</a> Instrumentation Science &amp; Technology. 44 (4), 386-400 (2016).</li><li>Kurata, M., Li, X., Fujita, K., Yamaguchi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Piezoelectric+dynamic+strain+monitoring+for+detecting+local+seismic+damage+in+steel+buildings.">Piezoelectric dynamic strain monitoring for detecting local seismic damage in steel buildings.</a> Smart Materials and Structures. 22 (11), 115002 (2013).</li><li>Qasaimeh, M. A., Sokhanvar, S., Dargahi, J., Kahrizi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PVDF-based+microfabricated+tactile+sensor+for+minimally+invasive+surgery.">PVDF-based microfabricated tactile sensor for minimally invasive surgery.</a> Journal of Microelectromechanical Systems. 18 (1), 195-207 (2009).</li></ol>

저자는 공개 상관이 있다.

이 프로토콜에 PVDF 필름 센서에 따라 동적 힘 측정 시스템은 성공적으로 고안, 조립, 측정 물 표면에서 접착 힘 보정. 전체 단계 가운데 그것은 중요 한 물에 빠른 공작의 현저한 특성에 초점을 맞춘이 연구로 수 면에서 다리를 들어올려 접착 힘 다른 속도에서 측정 했다. 출발 하는 실험의 결과 접착 힘 드는 속도 증가 감소 했다. 그들은 물에 고속에 이동 하는 경우 명확히 물 소금 느낄 것이 편안 ?...

자연 속에서 물 소금 점프 하거나 다리를 슬림 하 고 nonwetting1,2,3,,45의 도움으로 물 표면에 쉽고 빠르게 미끄러지듯이 놀라운 능력을 보유 하지만 드물게 지상파 곤충 달리는 천천히 이동 합니다. 물 스 트라이 더의 계층 구조 물과 다리6,,78, 사이 접촉 지역 및 접착 힘에 있는 극적인 감소를 렌더링 superhydrophobic 상태 안정화 그러나 9. 물 표면에서 물 소금의 빠른 해방의 유체역학 장점을 제대로 해석된10,,1112를 유지 하는.
물 표면에서 점프의 과정은 주로 3 단계13,14,,1516으로 분할 된다. 처음에 물 소금 곤충 초기화 점프 방향을 결정 하는 최대 깊이에 침 몰까지 생물 에너지 물의 표면 에너지로 변환 하 중간과 뒷 다리와 수 면 아래로 밀어 파견 속도입니다. 오름차순 단계 이어서, 곤충은 밀어 위쪽으로 곡선된 수 면의 모 세관 힘에 의해 최대 속도 도달까지. 최종 해방 단계에서 물 스 트라이 더 물 표면에서 속보까지 관성에 의해 상승 계속 하지만 속도 크게 접착 힘으로 감소, 물과 함께 있다는의 에너지 소비에 영향을 주는 물 스 트라이 더. 따라서,이 프로토콜은 해방 단계에서 다른 이륙 속도에 접착 힘을 측정 하 여 빠른 이동의 고유 특성을 설명 제안.
물 표면에서 추진 하는 때 물 소금의 접착 힘을 탐구 하는 많은 연구가 계속 있다. 리 & 김 이론적으로 그리고 실험적으로 접착 힘 및 에너지 접촉 각도 160도17에 증가 하는 때 극적으로 감소 물 스 트라이 더의 다리를 드는 필요한 확인. 팬 젠 웨이 18그것의 무게 1/5를 발견 되었다 TriboScope 시스템에 의해 접착 힘을 측정 하는 수압 실험 설계 되었습니다. Kehchih 황 다리 2D 모델 물에서 분리 하 고 다리의 superhydrophobicity 접착 힘 및 에너지 소산19감소에 중요 한 역할을 했다 발견의 준 정적 과정 분석. 그러나, 이전 연구에서 접착 력의 측정 빠른 점프 하는 동안 접착 힘 변화를 모니터링 하지 못했습니다 준 정적 과정의 상태에 그냥 했다.
이 연구에서 우리는 polyvinylidene 불 소 (PVDF) 필름 센서 및 다른 보조 장비를 사용 하 여 동적 힘 측정 시스템 설계. 다른 압 전 재료와 비교해, PVDF는 더 높은 감도20,,2122동적 microforce 측정 적합 합니다. 시스템에 PVDF 필름 센서를 통합 하 여 실시간 접착 힘 감지 고 다리는 물 표면23,,2425에서 당기는 때 처리 될 수 있습니다.

<table><tbody><tr><td>PVDF film sensor</td><td>TE Connectivity</td><td>DT1-028K/L</td><td>The PVDF film sensor is used to sense the dynamic contact force .</td></tr><tr><td>Charge amplifier</td><td>Wuxi Shiao Technology co.,Ltd</td><td>YE5852B</td><td>The charge amplifier&amp;nbsp;is an electronic current integrator that produces a voltage output proportional to the integrated value of the input</td></tr><tr><td>Data acquisition device</td><td>National Instruments</td><td>USB-4431</td><td>The data acquisition device is used to read the voltage data.</td></tr><tr><td>Displacement stage</td><td>ZOLIXINSTRUMENTS CO.LTD</td><td>KSAV1010-ZF</td><td>KSAV1010/2030-ZF is a wedge vertical stage with high-resolution, high-stability and high-load.</td></tr><tr><td>CCD camera</td><td>Shenzhen Andonstar Tech Co., Ltd</td><td>digital microscope A1</td><td>Frame rate: 30 frames/sec;Focal distance: 5mm - 30mm</td></tr><tr><td>Computer</td><td>Lenovo</td><td>G480</td><td></td></tr><tr><td>Servomotor</td><td>EMAX US Inc.</td><td>ES08MD</td><td>It&#039;s not bad this servo with speed varying from 0.10 sec/60&amp;deg; / 4.8v to 0.08 sec/60&amp;deg;/6.0v.</td></tr><tr><td>Mechanical Pipettes</td><td>Dragon Laboratory Instruments Limited</td><td>YE5K693181</td><td>The pipettes cover volume range of 0.1 &amp;mu;l to 2.5 &amp;mu;l</td></tr></tbody></table>

measurement of dynamic force acted on water strider leg jumping upward by the pvdf film sensor

이 연구 목적을 현상에 대 한 설명 자연에서 그 물 스 트라이 더 일반적으로 점프 또는 쉽게 하지만 빠르게 물 표면에 glides, 자사의 최대 운동 속도 도달 150 c m/s. 우선, 우리는 미세 및 스캐닝 전자 현미경을 사용 하 여 물 스 트라이 더 다리의 계층 구조 관찰. 다리의 관찰 된 형태학에 근거 하 여 물 표면에서 초연의 이론적 모델을 힘들이 지 않고 에너지 절감 측면에서 물 표면에 슬라이드 물 소금의 기능 설명 설립 되었다. 둘째, 동적 힘 측정 시스템 전체 상호 작용 프로세스를 검출할 수 있는 우수한 감도와 PVDF 필름 센서를 사용 하 여 고안 되었다. 그 후, 물과 접촉 한 다리는 위쪽으로 다른 속도로 접착 힘을 동시에 측정 되었다. 출발 실험 결과 물 소금의 빠른 점프에 대 한 깊은 이해를 제안 했다.

운동 속도 접착 힘 사이 관계는 표 1에 표시 됩니다. 드는 속도 0.01 m/s에서 0.3 m/s 증가, 접착은 물 표면 및 다리 감소 0.10에서 극적으로 0.03 사이 강제. 출발 실험의 결과 피크 접착 힘 드는 속도 증가, 물 소금 그들은 물 표면에 신속 하 게 이동 하는 경우 편안 하 게 느낄 수 있습니다 표시로 극적으로 감소 것이 보였다.
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Watch this Scientific Journal Video about Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor at JoVE.com

Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor

물 트라이 다리 PVDF 필름 센서에 의해 위쪽으로 점프에 행동 하는 동적 힘의 측정

여기에 프로토콜 자유 조사 하 고 빠른 공작 물 표면에 물 스 트라이 더의 전용입니다. 프로토콜에는 다리의 미세 관찰 하 고 다른 속도로 수 면에서 출발 하는 경우 접착 힘 측정 포함 됩니다.

This study aimed to make an explanation for the phenomenon in nature that water strider usually jumps or glides on the water surface easily but quickly, ...

measurement-dynamic-force-acted-on-water-strider-leg-jumping-upward

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

5.9K 조회수.  Tianjin University. 여기에 프로토콜 자유 조사 하 고 빠른 공작 물 표면에 물 스 트라이 더의 전용입니다. 프로토콜에는 다리의 미세 관찰 하 고 다른 속도로 수 면에서 출발 하는 경우 접착 힘 측정 포함 됩니다.

비디오: Measurement of Dynamic Force Acted on Water Strider Leg Jumping Upward by the PVDF Film Sensor

Kinematics and Ground Reaction Force Determination: A Demonstration Quantifying Locomotor Abilities of Young Adult, Middle-aged, and Geriatric Rats

Behavior, in its broadest definition, can be defined as the motor manifestation of physiologic processes. As such, all behaviors manifest through the motor system. In the fields of neuroscience and orthopedics, locomotion is a commonly evaluated behavior for a variety of disease models. For example, locomotor recovery after traumatic injury to the nervous system is one of the most commonly evaluated behaviors 1-3. Though locomotion can be evaluated using a variety of endpoint measurements (e.g. time taken to complete a locomotor task, etc), semiquantitative kinematic measures (e.g. ordinal rating scales (e.g. Basso Beattie and Bresnahan locomotor (BBB) rating scale, etc)) and surrogate measures of behaviour (e.g. muscle force, nerve conduction velocity, etc), only kinetics (force measurements) and kinematics (measurements of body segments in space) provide a detailed description of the strategy by which an animal is able to locomote 1. Though not new, kinematic and kinetic measurements of locomoting rodents is now more readily accessible due to the availability of commercially available equipment designed for this purpose. Importantly, however, experimenters need to be very familiar with theory of biomechanical analyses and understand the benefits and limitations of these forms of analyses prior to embarking on what will become a relatively labor-intensive study. The present paper aims to describe a method for collecting kinematic and ground reaction force data using commercially available equipment. Details of equipment and apparatus set-up, pre-training of animals, inclusion and exclusion criteria of acceptable runs, and methods for collecting the data are described. We illustrate the utility of this behavioral analysis technique by describing the kinematics and kinetics of strain-matched young adult, middle-aged, and geriatric rats.

Locomotion is often examined as a behavioural outcome in various models of disease in fields such as neuroscience and orthopedics. This video paper intends to describe a method for collecting ground reaction forces and kinematics from rats during unrestrained locomotion.

운동학 및 그라운드 반력 결정 : 젊은 성인, 중년과 노인 쥐의 데모 Quantifying 운전하는 능력

Behavior, in its broadest definition, can be defined as the motor manifestation of physiologic processes.  As such, all behaviors manifest through the ...

연구

신경과학

Studying the Neural Basis of Adaptive Locomotor Behavior in Insects

Studying the neural basis of walking behavior, one often faces the problem that it is hard to separate the neuronally produced stepping output from those leg movements that result from passive forces and interactions with other legs through the common contact with the substrate. If we want to understand, which part of a given movement is produced by nervous system motor output, kinematic analysis of stepping movements, therefore, needs to be complemented with electrophysiological recordings of motor activity. The recording of neuronal or muscular activity in a behaving animal is often limited by the electrophysiological equipment which can constrain the animal in its ability to move with as many degrees of freedom as possible. This can either be avoided by using implantable electrodes and then having the animal move on a long tether (i.e. Clarac et al., 1987; Duch &amp; Pfl&uuml;ger, 1995; B&ouml;hm et al., 1997; Gruhn &amp; Rathmayer, 2002) or by transmitting the data using telemetric devices (Kutsch et al, 1993; Fischer et al., 1996; Tsuchida et al. 2004; Hama et al., 2007; Wang et al., 2008). Both of these elegant methods, which are successfully used in larger arthropods, often prove difficult to apply in smaller walking insects which either easily get entangled in the long tether or are hindered by the weight of the telemetric device and its batteries. In addition, in all these cases, it is still impossible to distinguish between the purely neuronal basis of locomotion and the effects exerted by mechanical coupling between the walking legs through the substrate. One solution for this problem is to conduct the experiments in a tethered animal that is free to walk in place and that is locally suspended, for example over a slippery surface, which effectively removes most ground contact mechanics. This has been used to study escape responses (Camhi and Nolen, 1981; Camhi and Levy, 1988), turning (Tryba and Ritzman, 2000a,b; Gruhn et al., 2009a), backward walking (Graham and Epstein, 1985) or changes in velocity (Gruhn et al., 2009b) and it allows the experimenter easily to combine intra- and extracellular physiology with kinematic analyses (Gruhn et al., 2006).
We use a slippery surface setup to investigate the timing of leg muscles in the behaving stick insect with respect to touch-down and lift-off under different behavioral paradigms such as straight forward and curved walking in intact and reduced preparations.

We describe a method to record motor activity, timed to the electrically recorded tarsal contact signal in a tethered insect, walking on a slippery surface. This is used to study the neural basis of adaptive behavior under reduced influence of mechanical interaction between legs through the substrate.

곤충의 적응 운동력이있는 사람의 행동의 신경 기초를 공부

Studying the neural basis of walking behavior, one often faces the problem that it is hard to separate the neuronally produced stepping output from those ...

Image-based Lagrangian Particle Tracking in Bed-load Experiments

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a relatively low cost. This manuscript describes an application of particle tracking velocimetry (PTV) to a bed-load experiment with lightweight sediment. The key characteristics of the investigated sediment transport conditions were the presence of a covered flow and of a fixed rough bed above which particles were released in limited number at the flume inlet. Under the applied flow conditions, the motion of the individual bed-load particles was intermittent, with alternating movement and stillness terms. The flow pattern was preliminarily characterized by acoustic measurements of vertical profiles of the stream-wise velocity. During process visualization, a large field of view was obtained using two action-cameras placed at different locations along the flume. The experimental protocol is described in terms of channel calibration, experiment realization, image pre-processing, automatic particle tracking, and post-processing of particle track data from the two cameras. The presented proof-of-concept results include probability distributions of the particle hop length and duration. The achievements of this work are compared to those of existing literature to demonstrate the validity of the protocol.

The manuscript presents a protocol for the conduction of bed-load sediment transport experiments where the moving particles are tracked by image analysis. The experimental facility, the procedures for run realization and data processing, and finally some proof-of-concept results are presented here.

베드로드 실험에서 이미지 기반 라그랑주 입자 추적

Image analysis has been increasingly used for the measurement of river flows due to its capabilities to furnish detailed quantitative depictions at a ...

환경과학

Using Touch-evoked Response and Locomotion Assays to Assess Muscle Performance and Function in Zebrafish

Zebrafish muscle development is highly conserved with mammalian systems making them an excellent model to study muscle function and disease. Many myopathies affecting skeletal muscle function can be quickly and easily assessed in zebrafish over the first few days of embryogenesis. By 24 hr post-fertilization (hpf), wildtype zebrafish spontaneously contract their tail muscles and by 48 hpf, zebrafish exhibit controlled swimming behaviors. Reduction in the frequency of, or other alterations in, these movements may indicate a skeletal muscle dysfunction. To analyze swimming behavior and assess muscle performance in early zebrafish development, we utilize both touch-evoked escape response and locomotion assays.
Touch-evoked escape response assays can be used to assess muscle performance during short burst movements resulting from contraction of fast-twitch muscle fibers. In response to an external stimulus, which in this case is a tap on the head, wildtype zebrafish at 2 days post-fertilization (dpf) typically exhibit a powerful burst swim, accompanied by sharp turns. Our method quantifies skeletal muscle function by measuring the maximum acceleration during a burst swimming motion, the acceleration being directly proportional to the force produced by muscle contraction.
In contrast, locomotion assays during early zebrafish larval development are used to assess muscle performance during sustained periods of muscle activity. Using a tracking system to monitor swimming behavior, we obtain an automated calculation of the frequency of activity and distance in 6-day old zebrafish, reflective of their skeletal muscle function. Measurements of swimming performance are valuable for phenotypic assessment of disease models and high-throughput screening of mutations or chemical treatments affecting skeletal muscle function.

Zebrafish are an excellent model to study muscle function and disease. During early embryogenesis zebrafish begin regular muscle contractions producing rhythmic swimming behavior, which is altered when the muscle is disrupted. Here we describe a touch-evoked response and locomotion assay to examine swimming performance as a measure of muscle function.

터치 유발 대응 및 로코 분석 실험을 사용하여 Zebrafish의 근육의 성능 및 기능을 평가하기 위해

Zebrafish muscle development is highly conserved with mammalian systems making them an excellent model to study muscle function and disease. Many ...

발생학

Simulation of Human-induced Vibrations Based on the Characterized In-field Pedestrian Behavior

For slender and lightweight structures, vibration serviceability is a matter of growing concern, often constituting the critical design requirement. With designs governed by the dynamic performance under human-induced loads, a strong demand exists for the verification and refinement of currently available load models. The present contribution uses a 3D inertial motion tracking technique for the characterization of the in-field pedestrian behavior. The technique is first tested in laboratory experiments with simultaneous registration of the corresponding ground reaction forces. The experiments include walking persons as well as rhythmical human activities such as jumping and bobbing. It is shown that the registered motion allows for the identification of the time variant pacing rate of the activity. Together with the weight of the person and the application of generalized force models available in literature, the identified time-variant pacing rate allows to characterize the human-induced loads. In addition, time synchronization among the wireless motion trackers allows identifying the synchronization rate among the participants. Subsequently, the technique is used on a real footbridge where both the motion of the persons and the induced structural vibrations are registered. It is shown how the characterized in-field pedestrian behavior can be applied to simulate the induced structural response. It is demonstrated that the in situ identified pacing rate and synchronization rate constitute an essential input for the simulation and verification of the human-induced loads. The main potential applications of the proposed methodology are the estimation of human-structure interaction phenomena and the development of suitable models for the correlation among pedestrians in real traffic conditions.

A protocol is presented for the characterization of the in-field pedestrian behavior and the simulation of the resulting structural response. Field-tests demonstrate that the in situ identified pacing rate and synchronization rate among the participants constitute an essential input for the simulation and verification of the human-induced loads.

특성화에서 필드 보행자의 행동을 바탕으로 인간에 의한 진동의 시뮬레이션

For slender and lightweight structures, vibration serviceability is a matter of growing concern, often constituting the critical design requirement. With ...

공학

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: STW). Thus, in clinical rehabilitation separation of sit-to-stand and gait initiation - termed sit-to-stand-and-walk (STSW) - is usual. However, a standardized STSW protocol with a clearly defined analytical approach suitable for pathological assessment has yet to be defined.
Hence, a goal-orientated protocol is defined that is suitable for healthy and compromised individuals by requiring the rising phase to be initiated from 120% knee height with a wide base of support independent of lead limb. Optical capture of three-dimensional (3D) segmental movement trajectories, and force platforms to yield two-dimensional (2D) center-of-pressure (COP) trajectories permit tracking of the horizontal distance between COP and whole-body-center-of-mass (BCOM), the decrease of which increases positional stability but is proposed to represent poor dynamic postural control.
BCOM-COP distance is expressed with and without normalization to subjects&#39; leg length. Whilst COP-BCOM distances vary through STSW, normalized data at the key movement events of seat-off and initial toe-off (TO1) during steps 1 and 2 have low intra and inter subject variability in 5 repeated trials performed by 10 young healthy individuals. Thus, comparing COP-BCOM distance at key events during performance of an STSW paradigm between patients with upper motor neuron injury, or other compromised patient groups, and normative data in young healthy individuals is a novel methodology for evaluation of dynamic postural stability.

Here, we present a novel protocol to measure positional stability at key events during the sit-to-stand-to-walk using the center-of-pressure to the whole-body-center-of-mass distance. This was derived from the force platform and three-dimensional motion-capture technology. The paradigm is reliable and can be utilized for the assessment of neurologically compromised individuals.

앉아 - 투 - 독립 및-거리에 120 % 무릎 높이에서 : 소설 접근을 동적 자세 제어 독립적 인 리드 사지의 평가에

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: ...

행동분석학

A Rapidly Incremented Tethered-Swimming Maximal Protocol for Cardiorespiratory Assessment of Swimmers

Incremental exercise testing is the standard means of assessing cardiorespiratory capacity of endurance athletes. While the maximal rate of oxygen consumption is typically used as the criterion measurement in this regard, two metabolic breakpoints that reflect changes in the dynamics of lactate production/consumption as the work rate is increased are perhaps more relevant for endurance athletes from a functional standpoint. Exercise economy, which represents the rate of oxygen consumption relative to performance of submaximal work, is also an important parameter to measure for endurance-athlete assessment. Ramp incremental tests comprising a gradual but rapid increase in work rate until the limit of exercise tolerance is reached are useful for determining these parameters. This type of test is typically performed on a cycle ergometer or treadmill because there is a need for precision with respect to work-rate incrementation. However, athletes should be tested while performing the mode of exercise required for their sport. Consequently, swimmers are typically assessed during free-swimming incremental tests where such precision is difficult to achieve. We have recently suggested that stationary swimming against a load that is progressively increased (incremental tethered swimming) can serve as a &#34;swim ergometer&#34; by allowing sufficient precision to accommodate a gradual but rapid loading pattern that reveals the aforementioned metabolic breakpoints and exercise economy. However, the degree to which the peak rate of oxygen consumption achieved during such a protocol approximates the maximal rate that is measured during free swimming remains to be determined. In the present article, we explain how this rapidly incremented tethered-swimming protocol can be employed to assess the cardiorespiratory capacity of a swimmer. Specifically, we explain how assessment of a short-distance competitive swimmer using this protocol revealed that his rate of oxygen uptake was 30.3 and 34.8 mL&#8729;min-1&#8729;kg-1BM at his gas-exchange threshold and respiratory compensation point, respectively.

As opposed to measurement during free swimming, which presents inherent challenges and limitations, determination of important parameters of cardiorespiratory function for swimmers can be made using a more feasible and easier to administer tethered-swimming rapidly incremented protocol with gas exchange and ventilatory data collection.

수영 선수의 심폐 평가를위한 급속하게 증가 된 테더 드 수영 최대 프로토콜

Incremental exercise testing is the standard means of assessing cardiorespiratory capacity of endurance athletes. While the maximal rate of oxygen ...

생화학

Comparison of Kinetic Characteristics of Footwork during Stroke in Table Tennis: Cross-Step and Chasse Step

The cross-step and chasse step are the basic steps of table tennis. This study presents a protocol to investigate the ground reaction force characteristics between cross-step and chasse step during stroke in table tennis. Sixteen healthy male national level 1 table tennis players (Age: 20.75 &plusmn; 2.06 years) volunteered to participate in the experiment after understanding the purpose and details of the experiment. All participants were asked to hit the ball into the target zone by cross-step and chasse step, respectively. The ground reaction force in the anterior-posterior, medial-lateral, and vertical directions of the participant was measured by a force platform. The key finding of this study was that: the posterior ground reaction force of cross-step footwork (0.89 &plusmn; 0.21) was significantly large (P = 0.014) than the chasse step footwork (0.82 &plusmn; 0.18). However, the lateral ground reaction force of cross-step footwork (-0.38 &plusmn; 0.21) was significantly lower (P &lt; 0.001) than chasse step footwork (-0.46 &plusmn; 0.29) as well as the vertical ground reaction force of cross-step footwork (1.73 &plusmn; 0.19) was significantly lower (P &lt; 0.001) than chasse step footwork (1.9 &plusmn; 0.33). Based on the mechanism of the kinetic chain, the better lower limb dynamic performance of sliding stroke may be conducive to energy transmission and thus bring gain to the swing speed. Beginners should start from the chasse step to hit the ball technically, and then practice the skill of cross-step.

This study presents a protocol to investigate the ground reaction force characteristics between cross-step and chasse step during stroke in table tennis.

탁구 스트로크 중 발놀림의 운동 특성 비교: 크로스 스텝 및 체이스 스텝

The cross-step and chasse step are the basic steps of table tennis. This study presents a protocol to investigate the ground reaction force ...

A Micro-Displacement Measurement Based on the Shadow Technique

The precision measurement of micro displacement is important in scientific and industrial fields. However, it is a tough challenge due to the complex design and the high cost of measuring instruments. Inspired by the shadow formed from water striders walking on a water surface under sunlight, a micro-displacement measurement method was proposed. Water strider legs with superhydrophobic properties bend the water surface. The curved surface of the water refracts sunlight, creating a shadow with a bright edge at the bottom of the pond. The shadow size is generally larger than the indentation depth of the legs from the water surface. In the micro-displacement measurement system, the applied displacement is proportional to the change in the diameter of the shadow. The presented study proposes a micro-displacement measurement procedure based on this shadow technique. The displacement sensitivity can reach 10.0 nm/pixel in the range of 5 &#181;m. This system is simple to construct, low cost, and has high precision with good linear performance. The method provides a convenient additional option to measure micro-displacement.

High-precision micro-displacement measurement is significant in the field of aerospace engineering, ultra-precision machining, and micro-assembly. The present protocol describes measuring micro displacements based on the shadow technique.

The precision measurement of micro displacement is important in scientific and industrial fields. However, it is a tough challenge due to the complex ...

Force Measurement During Contraction to Assess Muscle Function in Zebrafish Larvae

Zebrafish larvae provide models of muscle development, muscle disease and muscle-related chemical toxicity, but related studies often lack functional measures of muscle health. In this video article, we demonstrate a method to measure force generation during contraction of zebrafish larval trunk muscle. Force measurements are accomplished by placing an anesthetized larva into a chamber filled with a salt solution. The anterior end of the larva is tied to a force transducer and the posterior end of the larva is tied to a length controller. An isometric twitch contraction is elicited by electric field stimulation and the force response is recorded for analysis. Force generation during contraction provides a measure of overall muscle health and specifically provides a measure of muscle function. Although we describe this technique for use with wild-type larvae, this method can be used with genetically modified larvae or with larvae treated with drugs or toxicants, to characterize muscle disease models and evaluate treatments, or to study muscle development, injury, or chemical toxicity.

Force measurements can be used to demonstrate changes in muscle function due to development, injury, disease, treatment or chemical toxicity. In this video, we demonstrate a method to measure force during a maximal contraction of zebrafish larval trunk muscle.

Zebrafish의 유충의 근육 기능을 평가하기 위해 수축하는 동안 힘 측정

Zebrafish larvae provide models of muscle development, muscle disease and muscle-related chemical toxicity, but related studies often lack functional ...