Peristaltic Pump Research Articles

Smooth Muscle Mechanosensitivity Generates and Maintains Pressure Gradients Across the Intestine.

The gut, the ureter, or the Fallopian tube all transport biological fluids by generating trains of propagating smooth muscle constrictions collectively known as peristalsis. These tubes connect body compartments at different pressures. We extend here Poiseuille's experiments on liquid flow in inert tubes to an active, mechanosensitive tube: the intestine. We use as a miniature myogenic peristaltic pump model, the fetal chicken gut, and measured the flow and contractile wave propagation as a function of the initially applied pressures and pressure gradients. We dissect the molecular pathways of smooth muscle mechanosensitivity by measuring the force generated by gut rings in different pharmacological conditions. We demonstrate that smooth muscle contractions in response to stretch or pressure is mediated by L-type Ca2+ channels and IP3 receptors. We show that this positive-feedback mechanosensitive behavior can spontaneously generate pressure gradients across gut segments initially subject to equal pressure; this same mechanism tends to stabilize initially applied pressure gradients; it can act jointly or compete with the pressure gradient induced by directional peristaltic waves. We demonstrate that high pressure differentials can reverse the physiological propagation direction of contractile waves imparted by interstitial cell of Cajal pacemaker activity. We find that flow rate increases with tube length, but that the maximum pressure differential generated depends solely on smooth muscle contractile force and on the initial resting pressure applied inside the organ. We provide fundamental mechanical and hydrodynamic insight into the myogenic mechanisms of transport in the gastrointestinal tract. We scale up our results to other human peristaltic organs and discuss their implications for pathophysiology of intestinal obstruction, vesicoureteral reflux and endometriosis.

A Novel Method for Mitochondrial Membrane Potential Detection in Heart Tissue Following Ischemia-reperfusion in Mice.

Myocardial ischemia-reperfusion (I/R) injury is associated with a significant reduction in the mitochondrial membrane potential (MMP, ΔΨm). Fluorescence-based assays are effective for labelling active mitochondria in living cells; their application in heart tissue, however, represents a challenge because of a low yield of viable cardiomyocytes after cardiac perfusion. This study aimed to examine a novel method for detecting the changes in the MMP of mouse heart tissue following I/R injury. The I/R model was established, which was characterized by distinct ischemic area and apoptosis in heart tissue. The MMP was detected via a confocal microscope after the ascending aorta was clamped and the mitochondrial probe solution (containing Mito-Tracker Deep Red FM) was perfused from the apex via a peristaltic pump. This method enabled the distribution of the probe solution throughout the cardiac tissue via the coronary circulation. Fluorescence detection revealed that the MMP was profoundly reduced in both ischemic area and border area following I/R when compared with that in the sham group. There was no obvious difference in the MMP of the remote area between the I/R group and the sham group. This study presents a novel method for detecting the MMP in heart tissue, and this method will facilitate the evaluation of changes in the MMP in different regions following I/R.

Preliminary steps for fabrication of microfluidic systems for swine sperm sorting: Materials, perfusing systems and flow

The success rate of assisted reproductive techniques in the livestock production can be optimized by improving the quality of the semen sample by selecting only the good quality sperm from the ejaculate. Microfluidic technology has been studied for sperm sorting mainly in human ejaculates but has not been studied for boar sperm. Spermatozoa have been proven to be highly sensitive to different microplastics, but the potential toxic effects of the materials used to set up microfluidic systems have not been studied. The main goal of this study was to assess the possible toxic effect on boar sperm of materials commonly used for a microfluidic system and to evaluate the effect of different flow control systems (peristaltic pump, syringe pump and a microfluidic flow controller) at different flow rates (10 μl*min-1, 100 μl*min-1 and 1 ml*min-1) on sperm quality, as preliminary information for the development of a swine sperm sorting microfluidic system. Results showed no negative effect of the different materials at different concentrations. The control reached the highest curvilinear velocity compared to the peristaltic pump and the pressure-based flow control system. In the flow rates, 10 μm*min-1 showed the poorest results and no significant differences were observed between control and 1 mlmin-1 flow in any of the parameters. In conclusion, all materials that were studied for microfluidic fabrications were suitable for sperm sorting, any of the pumps would be suitable for sperm selection and 1 ml*min-1 flow rate would be the flow rate of choice for sperm pumping.

Thermal performance of radiative hydromagnetic peristaltic pumping of hybrid nanofluid through curved duct with industrial applications

Thermal performance of peristaltic pump are significant to enhance the efficiency of the system. Heat transfer analysis for peristalsis of hybrid nanofluid through a curved duct is investigated here. Effect of radially varying magnetic field, Joule heating and heat generation/absorption are taken into consideration. Viscous dissipation and thermal radiation effects are considered to improve the heat transfer rate. Thermal and viscous characteristics are varying according to temperature. Velocity slip and temperature jump constraints are employed to solve the problem. The solution of resulting system are obtained under the lubrication technique. Curvature effect are also discussed to observe variation in the flow rate. NDSolve is built in shooting technique that are used in Mathematica software to find the solution. Numerical results for pertinent non-dimensional parameters are presented graphically. Heat transfer characteristics are represented through table. Results revealed that the inclusion of nanomaterials in liquid improves the cooling process and perturbs the flow rate. Comparative analysis indicates that heat transfer rate are 4% higher in the case of copper nanomaterial as compare to iron oxide nanomaterial. The results of present study has relevance with cancer therapy, heart surgery and drug delivery processes.

Design, optimization, simulation, and implementation of a 3D printed soft robotic peristaltic pump

Abstract This study presents an innovative approach to fluidic pumping using soft robotics, designed to circulate fluid through soft conduits for delicate environments like blood streams where traditional peristaltic pumps may not be feasible. A novel soft robotic peristaltic pump is optimized and implemented, featuring 3D printed ring-shaped actuators and a PDMS pipe housing a Newtonian fluid. The design includes a three-stage actuator ring structure, actuated sequentially for peristaltic motion. A parametric finite element model predicts the required pressure, and the Mooney-Rivlin 5 Parameters hyper-elastic material model ensures accurate material properties. Optimization uses response surface analysis in Minitab and MATLAB Simulink Simscape simulations to achieve maximum flow rate with minimal power and pressure. Experimental validation confirms the simulations, achieving an optimal flow rate of 0.27 ml s−1 at a 450 ms cycle, with minor discrepancies due to friction and measurement errors. This study demonstrates the scalability of linearly sequenced soft squeeze actuators into an effective pump, validated by both simulation and experiments. Future applications include medical devices addressing deep venous thrombosis, with further research exploring control theory for optimization and comparing performance with conventional pumps to enhance practical applicability.

An optimized Langendorff-free method for isolation and characterization of primary adult cardiomyocytes

Isolation of adult mouse cardiomyocytes is an essential technique for advancing our understanding of cardiac physiology and pathology, and for developing therapeutic strategies to improve cardiac health. Traditionally, cardiomyocytes are isolated from adult mouse hearts using the Langendorff perfusion method in which the heart is excised, cannulated, and retrogradely perfused through the aorta. While this method is highly effective for isolating cardiomyocytes, it requires specialized equipment and technical expertise. To address the challenges of the Langendorff perfusion method, researchers have developed a Langendorff-free technique for isolating cardiomyocytes. This Langendorff-free technique involves anterograde perfusion through the coronary vasculature by clamping the aorta and intraventricular injection. This method simplifies the experimental setup by decreasing the need for specialized equipment and eliminating the need for cannulation of the heart. Here, we introduce an updated Langendorff-free method for isolating adult mice cardiomyocytes that builds on the Langendorff-free protocols developed previously. In this method, the aorta is clamped in situ, and the heart is perfused using a peristaltic pump, water bath, and an injection needle. This simplicity makes cardiomyocyte isolation more accessible for researchers who are new to cardiomyocyte isolation or are working with limited resources. In this report, we provide a step-by-step description of our optimized protocol. In addition, we present example studies of analyzing mitochondrial structural and functional characteristics in untreated isolated cardiomyocytes and cardiomyocytes treated with the acute inflammatory stimulus lipopolysaccharide (LPS).

An Arteriovenous Bioreactor Perfusion System for Physiological In Vitro Culture of Complex Vascularized Tissue Constructs.

The generation and perfusion of complex vascularized tissues in vitro requires sophisticated perfusion techniques. For multiscale arteriovenous networks, not only the arterial, but also the venous, biomechanical and biochemical conditions that physiologically exist in the human body must be accurately emulated. For this, we here present a modular arteriovenous perfusion system for the in vitro culture of a multi-scale bioartificial vascular network. The custom-built perfusion system consisted of two circuits: in the arterial circuit, physiological arterial biomechanical and biochemical conditions were simulated using a modular set-up with a pulsatile peristaltic pump, compliance chambers, and resistors. In the venous circuit, venous conditions were emulated accordingly. In the center of the system, a bioartificial multi-scale vascularized fibrin-based tissue was perfused by both circuits simultaneously under biomimetic arteriovenous conditions. Culture conditions were monitored continuously using a multi-sensor monitoring system. The physiological arterial and venous pressure- and flow-curves, as well as the microvascular arteriovenous oxygen partial pressure gradient, were accurately emulated in the perfusion system. The multi-sensor monitoring system facilitated live monitoring of the respective parameters and data-logging. In a proof-of-concept experiment, vascularized three-dimensional fibrin tissues showed sustained cell viability and homogenous microvessel formation after culture in the perfusion system. The arteriovenous perfusion system facilitated the in vitro culture of a multiscale vascularized tissue under physiological pressure-, flow-, and oxygen-gradient conditions. With that, it presents a promising technique for the in vitro generation and culture of complex large-scale vascularized tissues.

A modular, human body-mimicking phantom with active thermoregulation capabilities for validation and verification of convective hyperthermia devices

Objectives This study aims to design and fabricate a modular phantom for hyperthermia applications, addressing interpatient variability in thermal regulation mechanisms like sweating rate, metabolic heat production, and blood redistribution. Materials & methods The phantom can be constructed in various weights and dimensions by connecting identical units. Each unit consists of an agar-based block, an ethyl cellulose-based top layer, a heat source, deep and superficial water circulation, and a sweating mechanism. Agar and ethyl cellulose gels mimic the thermal properties of human tissues and fat respectively. The blocks are wrapped in PVC foil to prevent water evaporation. A heating wire, coiled around an embedded aluminum tubing simulates metabolic heat production. A superficial water circulation mimics skin capillaries. A water pump ensures a steady flow rate throughout the tubing system. Sweat production is simulated using a water pump and perforated tubing. A programmed controller maintains core temperature in a normal operating mode and simulates an anesthetized patient in anesthesia mode. Results Temperature uniformity and regulation were assessed under varying environmental conditions. The phantom effectively regulated its core temperature at 37.0 °C +/- 0.7 °C with an ambient temperature ranging between 21 °C and 30 °C. Activating the water circulation reduced the maximum temperature gradient within the phantom from 4.70 °C to 1.92 °C. Conclusion The versatile phantom successfully models heat exchange processes. Its thermal properties, dimensions, and heat exchange rates can be tuned to mimic different patient models. These are promising results as an effective tool for hyperthermia device validation and verification, representing human physiological responses.

Controlled entropy in tetra-hybrid nono-fluid helmholtz electroosmotic with motile germs via complex peristaltic pumping

Motile microorganisms, such as bacteria, can be engineered to transport medications directly to certain organs, such as cancer, tumors, enhancing drug efficacy and minimizing systemic side effects. These microorganisms can also be programmed to target and eliminate harmful bacteria, offering a novel approach to infection control. In parallel, functionalized nanomaterials show significant promise for precise manipulation of biological fluids. This focused approach improves drug efficacy while reducing systemic negative effects. Also, motile bacteria can be engineered to target and remove dangerous bacteria, providing a fresh approach to infection control. Nanomaterials with various functions show prodigious potential for precise operation of biological fluids. Tetra-hybrid nano-particles exhibit special electrical, optical, and thermal properties. They are composed of gold, silver, alumina, and titania. The streaming flow phenomena that result from the interactions of these nanocomposites with non-Newtonian biofluids, such as blood, can be studied using computational modeling. Considerations are made for forces such as non-Newtonian rheology, localized laser irradiation, and magnetohydrodynamics. Complex cellular trapping patterns are captured by predictions for temperature, velocity, and nanoparticle concentration profiles. Biocompatible multimodal nano-assemblies under magnetic actuation and thermos-plasmonic effects are used to exhibit precision biofluid control. To optimize, engineering parameters are visually analyzed. The unique features of tetra-hybrid nanoparticles, paired with motile microorganisms and non-Newtonian biofluid dynamics, allow for more precise therapeutic techniques, such as targeted medication administration and hyperthermia cancer treatment. By visualizing key engineering parameters, these findings highlight the potential for improved therapeutic strategies, such as targeted drug delivery and hyperthermia-based cancer treatments, enabled by the integration of tetra-hybrid nanoparticles and motile microorganisms in complex biofluid environments.

Using UAVs to collect filtered water samples for mineral exploration: Will it take off?

The advent of unmanned aerial vehicle (UAV) assisted surface water sampling and ongoing technological advances in sampling and data acquisition, offers many opportunities to conduct high-quality hydrogeochemical surveys with low cost, high efficiency, and reduced human interactions. Hydrogeochemical mineral exploration is one area that could greatly benefit from a UAV sampling revolution, with survey sites often located in highly remote areas with limited existing infrastructure. Currently, a lack of point source filtration and complicated physiochemical data acquisition hinder mainstream UAV deployment in the context of hydrogeochemical studies. The aim of this paper is to provide guidance on effective UAV sampling methods and physiochemical data collection for use in surface water hydrogeochemical mineral exploration. To date, case study surveys have utilized sampling systems where sampled waters are filtered after collection or analyzed for ‘total’ (unfiltered) concentrations. This paper details a methodology for point-source filtration of water samples using a UAV system to recover filter sample aliquots for the determination of ‘dissolved’ (<0.45 μm) trace element concentrations and compares UAV methods to conventional sampling strategies. This study systematically compares the quality of analytical data collected from lakes, ponds, and rivers in the Long Lake area of southern Ontario, using conventional manual sampling (from a boat or canoe) and a series of UAV-based sampling methodologies. The waters sampled within the study area are highly meteoric and show evidence of solute input from water-rock interaction with local country rocks. The results of this study show that in general, conventional sampling methodologies are statistically comparable to samples collected using UAVs. However, there is some evidence of element variation related to lake stratification, with dissolved Cu concentrations higher in samples collected at depth compared to those from the surface. Similarly, samples filtered after collection typically have lower concentrations of Fe and Mn, potentially resulting from precipitation before filtration. An enclosed sampling system offered from peristaltic pumping with in-line filtration removes the potential for contamination from the surrounding environment and from the UAV itself.

Interaction of preservatives with contact materials during filling and storage of parenteral liquid formulations

Silicone tubing is a frequently used material in pharmaceutical filling processes for parenteral formulations, as its characteristics like flexibility, chemical resistance and easy handling make it particularly suitable for these purposes. This study investigated the time-dependent interaction of phenol and m-cresol with silicone tubing and other broadly applied contact materials used during the filling and transport processes of parenteral formulations. Phenol losses could be observed after incubation in silicone tubing, depending on the inner diameter (ID). This has been demonstrated for process interruptions of up to 120 minutes. A loss of 40 % could be observed for a small ID of 3.2 mm which can be found close to filling needles, and up to 12 % for larger tubes with an ID of 9.5 mm commonly used for sterile filtration and transport processes. Analysis of tubes with varying ID revealed a linear relationship between the decrease of phenol and the surface-to-volume ratio. m-cresol showed an even more pronounced loss in silicone tubing. Fluorinated polymers and thermoplastic elastomers were also analyzed, and no loss of phenol and m-cresol was observed. Pumping tests revealed that shear forces in peristaltic pumps led to strong particle formation in selected tubing. A strong increase in particle concentration was observed in thermoplastic elastomers, particularly in PharMed® BPT tubing. In contrast, the C-Flex® tubing demonstrated minimal particle formation. Fluorinated polymers are not compatible with peristaltic pumps, which is why they were not analyzed regarding pumpability. Although silicone tubes are not impervious to preservatives such as phenol, they did not generate particles when pumped.

Influence of magnetic field and activation energy on creeping flow of tri-hybrid nanofluid driven by peristaltic pumping in an asymmetric channel with synthetic cilia

In this study we explored the effects of magnetic field and activation energy on creeping flow of Fe3O4-Zn-Ag/blood-based tri-hybrid nanofluid through an asymmetric channel adorned with synthetic cilia. Also incorporated double diffusion, heat and mass transfer effects via Porous medium is considered. The channel walls are covered with cilium that facilitates flow actuation. The mathematical model is formed for the present issue and non dimensionalised by employing the appropriate dimensionless parameters and solved the non linear partial differential equation by using Homotopy Perturbation method. The flow properties are examined for various factors. The concept of trapping has also been described using streamlines. The significant outcome of this study is that, due to ciliated wall velocity declines close to the channel’s walls and it develops at the centre, where as it shows exactly opposite nature to magnetic field. Additionally temperature and concentration increases with activation energy and they shows opposition to magnetic field. By raising the magnetic field and decreasing the cilium filament and eccentricity parameters, the trapped bolus shrinks in size. By incorporating nanoparticles into the basic fluid, nanofluid improves heat transmission. The radiated ternary nanofluid under magnetic field effects may help with cooling by eliminating additional heat from the system.

Evaluation of extra-corporeal membrane oxygenator cannulae in pulsatile and non-pulsatile pediatric mock circuits.

This study evaluated the hemodynamic performance of arterial and venous cannulae in a compliant pediatric extracorporeal membrane oxygenation (ECMO) mock circuit in pulsatile and non-pulsatile flow conditions. The ECMO setup consisted of an oxygenator, diagonal pump, and standardized-length arterial/venous tubing with pressure transducers. A validated left-heart mock loop was adapted to simulate pediatric conditions. The pulsatile flow was driven by a computer-controlled piston pump set at 120 bpm. A roller pump was used for non-pulsatile conditions. The circuit was primed with 40% glycerol-based solution. The cardiac output was set to 1 L/min and the aortic pressure to 40-50 mmHg. Four arterial cannulae (8Fr, 10Fr, 12Fr, 14Fr) and five venous cannulae (12Fr, 14Fr, 16Fr, 18Fr, 20Fr) (Medtronic, Inc., Minneapolis, MN, USA) were tested at increasing flow rate in 12 combinations. The pulsatile condition required lower ECMO pump speeds for all cannulae combinations at a given flow rate, inducing a significantly smaller increase of flow in the mock loop. Under non-pulsatile conditions, the aortic and arterial pressures in the cannulae were higher (p < 0.01) while no significant differences in pressure drop and pressure-flow characteristics (M-number) were observed. The total hemodynamic energy was higher in case of non-pulsatile flow (p < 0.01). Under non-pulsatile conditions, the system was characterized by overall higher pressures, resulting in higher support to the patient. The consequent increase of potential energy compensates for increases of kinetic energy, leading to a higher total hemodynamic energy. Pressure gradients and M number are independent of the testing conditions. Pulsatile testing conditions led to more physiological testing conditions, and it is recommended for ECMO testing.

Entropy generation outcomes in peristalsis of Carreau–Yasuda nanofluid flow with activation energy

AbstractThis paper focuses on the study of activation energy and entropy generation in the peristaltic flow of a Carreau–Yasuda nanofluid. Peristaltic transport, coupled with entropy generation and activation energy in a curved geometry, has significant applications in biomedical and industrial processes involving non‐Newtonian fluids. Blood flow in the arteries, the movement of chyme in the gastrointestinal tract, and peristaltic motion replicate the natural muscular contractions that drive fluid flow in the physiological systems. The integration of entropy generation allows for the evaluation of energy efficiency and the analysis of losses due to viscous dissipation. Activation energy plays a crucial role in processes such as drug delivery, where temperature‐sensitive reactions or biochemical changes affect fluid behavior. In industrial applications, like peristaltic pumps in chemical reactors or polymer processing, the consideration of entropy and activation energy aids in optimizing thermal management and reaction rates. The mathematical model is developed under these assumptions, and the governing equations are numerically solved using the NDSolve function in Mathematica. Graphical results show that higher activation energy and concentration reduce the reaction rate, while the Bejan number and entropy generation increase with a larger Brinkman number. Velocity and temperature increase under slip conditions, whereas concentration decreases, and a stronger radial magnetic field reduces both velocity and the size of the trapped bolus.

One-shot manufacturable soft-robotic pump inspired by embryonic tubular heart.

Soft peristaltic pumps, which use soft ring actuators instead of mechanical pistons or rollers, offer advantages in transporting liquids with non-uniform solids, such as slurry, food, and sewage. Recent advances in 3D printing with flexible thermoplastic polyurethane (TPU) present the potential for single-step fabrication of these pumps, distinguished from handcrafted, multistep traditional silicone casting methods. However, because of the relatively high hardness of TPU, TPU-based soft peristaltic pumps contract insufficiently and thus cannot perform as well as silicone-based ones. Improving the performance is crucial for fully automated, one-step manufactured soft pumps to lead to industrial use. This study aims to enhance TPU-based soft pumps through bioinspired design. Specifically, it proposed a design inspired by embryonic tubular hearts, in contrast to previous studies that mimicked digestive tracts. The new design facilitated long-axis stretching of an elliptical lumen during non-concentric contractile motion, akin to embryonic tubular hearts. The design was optimized for ring actuators and pumps 3D-printed with shore hardness 85 A TPU filament. The ring actuator achieved over 99% lumen closure with the best designs. The soft pumps transported water at flow rates of up to 218 ml min-1and generated a maximum discharge pressure of 355 mm Hg, comparable to the performance of blood pumps used in continuous renal replacement therapy.

Impact of surface tension, viscosity, pump settings, and nozzle size on filling process capability and accuracy in high-concentration biopharmaceuticals

Filling is the final critical unit operation in the manufacturing process of liquid biological drug products. This paper thoroughly investigates the influence and mechanisms of peristaltic pump settings, nozzle size, product surface tension and viscosity on the biopharmaceutical filling processes based on the established filling process model of surrogates. Our study highlights the significant role of pump settings in influencing filling process capability indexes, in addition to their primary function of regulating flow rate. Surface tension minimally impacts flow behavior but significantly regulates the final dropʼs behavior, with lower surface tension increasing dripping tendencies. Viscosity proves crucial; higher viscosity intensifies friction and head loss of filling flow in tube/nozzle, causing pressure and flow rate losses, more pronounced dripping, and worse filling accuracy. Furthermore, nozzle size moderates the impact of pump settings, surface tension, and viscosity on filling performance. Larger nozzles help mitigate these effects, contributing to enhanced stability in filling performance under challenging conditions. For high-concentration biopharmaceuticals with elevated viscosity during filling, utilizing larger nozzles and reducing pump speed could achieve enhanced Cpk values and improved filling accuracy. Understanding the complex interactions among these factors is vital for optimizing the biopharmaceutical industry, promoting cost-effective practices, and enhancing production efficiency.

Electroosmotically assisted peristaltic propulsion of blood-based hybrid nanofluid through an endoscope with activation energy

The main aim of this research work is to analyze the peristaltic pumping of hybrid nanofluid through an endoscope. Here, blood is considered as base fluid and iron-oxide and gold are considered as nanoparticles. The non-Newtonian behavior of blood is studied through the Casson fluid model. The effect of nanoparticles is included in the mathematical formulation by using the modified version of Buongiorno model. Moreover, the effects of motion due to electroosmosis, activation energy, and Joule heating are also considered in fluid flow. The obtained non-linear system of equations after imposing lubrication approach is solved using Mathematica. The flow properties subject to variation in different involved parameters is analyzed through graphical results. It is assessed from graphical results that for larger Casson fluid parameters, fluid flow is more accelerated. It is also observed that presence of hybrid nanoparticles improves the velocity profile as well as cooling tendency of the working fluid when compared with the case of mono nanofluid. The electroosmotic phenomenon works a key parameter that can control the fluid flow by either assisting and opposing the flow. It has observed that a larger Debye length parameter, assisting electric field, and larger activation energy parameter reduce the nanoparticle concentration.

Electroosmotic peristaltic transport of magnetohydrodynamic Casson nanofluid in a non-uniform wavy porous asymmetric micro-channel

Magnetohydrodynamics (MHD) have numerous engineering and biomedical applications such as sensors, MHD pumps, magnetic medications, MRI, cancer therapy, astronomy, cosmology, earthquakes, and cardiovascular devices. In view of these applications and current developments, we investigate the magnetohydrodynamic MHD electro-osmotic flow of Casson nanofluid during peristaltic movement in a non-uniform porous asymmetric channel. The effect of thermal radiation, heat source, and Hall current on the Casson fluid peristaltic pumping in a porous medium is taken into consideration. The effect of chemical reactions is also considered. The mass, momentum, energy, and concentration equations were constructed using the proper transformations and dimensionless variables to make them easier for non-Newtonian fluids. A lubricating strategy is used to make the system less complicated. The Boltzmann distribution of electric potential over an electric double layer is studied using the Debye–Huckel approximation. The temperature and concentration equations are addressed using the homotopy perturbation method (HPM), while the exact solution is determined for the velocity field. The study examines the performance of velocity, pressure rise, temperature, concentration, streamlines, Nusselt, and Sherwood numbers for the involved parameters using graphical illustrations and tables. Asymmetric channels exhibit varying behavior, with velocity declining near the left wall and accelerating towards the right wall while enhancing the Casson fluid parameter. The pumping rate boosts in the retrograde region due to the evolution of the permeability parameter value, while it declines in the augment region. The temperature profile optimizes as the value of the heat source parameter gets higher. The concentration profile significantly falls as the chemical reaction parameter rises. The size of the trapped bolus strengthens with a spike in the parameter for the Casson fluid.

Susceptibility of two different PCA pumps to inaccurate delivery associated with pole position at low flow-rates in a pediatric setting - an experimental study.

Vertical displacement of infusion pumps used in patient-controlled analgesia can cause irregularities in drug delivery and is especially crucial at low flow rates, which are commonly used in pediatrics. There is only scarce data available regarding the extent of these inaccuracies. The current in vitro study therefore aimed at a comparison of the performance of two commonly used PCA pumps at different pole positions due to vertical displacement. The Syramed® µSP6000 Chroma syringe infusion pump featuring a stepper motor drive was compared to the CADD®-Solis pump utilizing a linear peristaltic pump system at two different flow rates (0.3ml/h and 1ml/h) and three different levels of height (0, + 50 and - 50cm). Flow patterns and delivered volumes were measured after every change in position and infusion boluses, retrograde aspiration volumes and zero-drug delivery time were calculated. The Syramed® pump was more susceptible to vertical displacement than the CADD®-Solis pump and showed overall greater inaccuracies in the delivered volumes as well as higher infusion boluses, retrograde aspiration volumes and zero-drug delivery time at both flow rates. The observed differences between the pumps might be explained by the higher compliance of this syringe pump and the diverse working mechanisms. Overall, the CADD®-Solis pump might be considered a preferable option for patient-controlled analgesia in children. It is nonetheless essential for medical staff to be aware of the effects of vertical displacement of PCA pumps and to minimize these displacements as much as possible.

Role of silver nanoparticle in thermal energy process regulated by peristalsis

Electroosmosis regulated model of peristalsis with nanoparticles is significant for heat transfer efficiency regarding optimization of thermal energy process. Such investigation is useful for processes in nano-drug delivery systems, pharmacology, renewable energy, energy saving, drying, biochip fabrication, Sensing and imagining, hyperthermia, cryosurgery, oil mobility improvement, filtration and purification, drilling, cell separation and microelectro-mechanical Systems (MEMS). Therefore, mixed convective peristaltic flow of nanomaterial filling porous medium is addressed. Asymmetric flow configuration is taken. Nanomaterial comprising silver and water is considered. Thermal radiation and dissipation are invoked. Peristaltic pumping is studied under the process of electroosmosis. Electroosmosis process is modeled by Nernst-Planck and Poisson equations. Debye-Huckel assumption is used for electric potential distribution along electron double layer. Velocity slip and convective boundary constraints are considered in this analysis. Dimensionless equations are presented employing lubrication approach. Related problems have been computed numerically. Behaviors of temperature, velocity, pressure gradient and streamlines are examined graphically. Heat transfer coefficient is also studied. Result shows that temperature decreases by volume fraction of nanoparticle. Pressure gradient decays for larger porosity. Temperature reduces for larger radiation. Rate of heat transfer enhances by Grashof number whereas it reduces by volume fraction of nanoparticles.