The effect of some endogenous components -endogenous opiates, cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP) and somatostatin-as inhibitory or excitatory transmitters in the local nervous pathways involved in peristaltic responses was examined. The peristaltic reflex was studied using a modification of the Trendelenberg preparation. In each preparation, the luminal distens...

We present an Immersed Boundary method for interactions between elastic boundaries and mixtures of two fluids. Each fluid has its own velocity field and volume-fraction. A penalty method is used to enforce the condition that both fluids' velocities agree with that of the elastic boundaries. The method is applied to several problems: Taylor's swimming sheet problem for a mixture of two viscous f...

This study presents a double-side diaphragm peristaltic pump for efficient medium transport without the unwanted backflow and the lagging effect of a diaphragm. A theoretical model was derived to predict the important parameter of the micropump, i.e., the motion of the valves at large deformations, for a variety of air pressures. Accordingly, we proposed an easy and robust design to fabricate a...

Peristaltic pumping is a mechanism for transporting fluid or immersed particles in a channel by waves of contraction. It occurs in many biological organisms as well as in several human designed systems. In this study, we investigate numerically the peristaltic pumping of an incompressible viscoelastic fluid using the simple Oldroyd-B model coupled to the Navier-Stokes equations. The pump’s wall...

Anatomical structures are rarely static during a surgical procedure due to breathing, heartbeats, and peristaltic movements. Inspired by observing an expert surgeon, we propose an intermittent synchronization with the extrema of the rhythmic motion (i.e., the lowest velocity windows). We performed 2 experiments: (1) pattern cutting, and (2) debridement. In (1), we found that the intermittent sy...

The Problem of peristaltic transport of a fluid with magnetic fluid with variable viscosity through the gap between coaxial tubes where the outer tube is non-uniform with sinusoidal wave traveling down is wall and the inner tube is rigid. The relation between the pressure gradient, friction force on the inner and outer tube are obtained in terms of magnetic fluid and viscosity. The numerical so...

INTRODUCTION: Heavily T2-weighted high-resolution 3D sequences using respiratory compensation methods have become the standard for magnetic resonance cholangiopancreatography (MRCP) examinations [1]. Due to the long acquisition time, this type of sequence is susceptible to motion artifact from surrounding bowel structures. Butylscopolamine (Buscopan® Boehringer Ingelheim GmbH) is often used as ...

This paper presents lumped-parameter simulation of dynamic characteristics of peristaltic micropumps. The pump consists of three pumping cells connected in series, each of which is equipped with a compliant diaphragm that is electrostatically actuated in a peristaltic sequence to mobilize the fluid. Diaphragm motion in each pumping cell is first represented by an effective spring subjected to h...

To simulate body organ motion due to breathing, heart beats, or peristaltic movements, we designed a lowcost, miniaturized SPRK (Stewart Platform Research Kit) to translate and rotate phantom tissue. This platform is 20cm× 20cm×10cm to fit in the workspace of a da Vinci Research Kit (DVRK) surgical robot and costs $250, two orders of magnitude less than a commercial Stewart platform. The platfo...

Widely used for modeling biological fluids flows—in particular, blood vessel flows—a Casson flow is studied in a symmetric channel which the aspect ratio enables one to use lubrication approximation. Two driving conditions are prescribed: inlet–outlet pressure difference and peristaltic oscillations of walls. In both cases, starting from mass momentum balance using approximation, we investigate...