Human in vivo baseline intrarenal pressure, peristaltic activity and response to ureteric stenting.

OBJECTIVES: To assess human in vivo intrarenal pressure (IRP) and peristaltic activity at baseline and after ureteric stent placement, using a narrow calibre pressure guidewire placed retrogradely in the renal pelvis. PATIENTS AND METHODS: A prospective, multi-institutional study recruiting consenting patients undergoing ureteroscopy was designed with ethical approval. Prior to ureteroscopy, the urinary bladder was emptied and the COMET™ II pressure guidewire (Boston Scientific) was advanced retrogradely via the ureteric orifice to the renal pelvis. Baseline IRPs were recorded for 1-2 min. At procedure completion, following ureteric stent insertion, IRPs were recorded for another 1-2 min. Statistical analysis of mean baseline IRP, peristaltic waveforms and frequency of peristaltic contractions was performed, thereby analysing the influence of patient variables and ureteric stenting. RESULTS: A total of 100 patients were included. Baseline mean (±SD) IRP was 16.76 (6.4) mmHg in the renal pelvis, with maximum peristaltic IRP peaks reaching a mean (SD) of 25.75 (17.9) mmHg. Peristaltic activity generally occurred in a rhythmic, coordinated fashion, with a mean (SD) interval of 5.63 (3.08) s between peaks. On univariate analysis, higher baseline IRP was observed with male sex, preoperative hydronephrosis, and preoperative ureteric stenting. On linear regression, male sex was no longer statistically significant, whilst the latter two variables remained significant (P = 0.004; P < 0.001). The mean (SD) baseline IRP in the non-hydronephrotic, unstented cohort was 14.19 (4.39) mmHg. Age, α-blockers and calcium channel blockers did not significantly influence IRP, and no measured variables influenced peristaltic activity. Immediately after ureteric stent insertion, IRP decreased (mean [SD] 15.18 [5.28] vs 16.76 [6.4] mmHg, P = 0.004), whilst peristaltic activity was maintained. CONCLUSIONS: Human in vivo mean (SD) baseline IRP is 14.19 (4.39) mmHg in normal kidneys and increases with both hydronephrosis and preoperative ureteric stenting. Mean (SD) peristaltic peak IRP values of 25.75 (17.9) mmHg are reached in the renal pelvis every 3-7 s and maintained in the early post-stent period.

Peristaltic Motion Enabled by Pneumatic Artificial Muscles (PAMs) as Structural "Soft-Stiff" Actuators in a Modular Worm-Inspired Robot.

This paper considers the design, manufacture, and testing of a prototype "soft-stiff" worm-inspired robot referred to herein, as the PneumaticallyActuated PeristaLtic Advancing Modular (PALAM) robot. The robot has a modular structure, mimicking the segmented nature of earthworms, and each segment is individually actuated by a set of three pneumatic artificial muscles (PAMs). The PAMs contract when inflated by pressurised air, generating a pulling force and fulfilling the role of biological muscles in the robot. The PAMs are made from the elastomer silicone rubber, which affords the robot flexibility and enables a wide range of real-life applications. A control-system is designed which can inflate any PAM on demand, and hence replicate the peristaltic motion of earthworms in the PALAM robot. Finally, this paper discusses a successful, low-cost, and widely accessible approach for the manufacture of the PAMs utilised herein. The PAMs can be scaled dimensionally and made from different materials with varying mechanical properties and behaviours, meaning that they are suitable for use in a wide range of robotics applications.

In-use stability of Rituximab and IVIG during intravenous infusion: Impact of peristaltic pump, IV bags, flow rate, and plastic syringes.

This study investigates the impact of intravenous (IV) infusion protocols on the stability of Intravenous Immunoglobulin G (IVIG) and Rituximab, with a particular focus on subvisible particle generation. Infusion set based on peristaltic movement (Medifusion DI-2000 pump) was compared to a gravity-based infusion system (Accu-Drip) at different flow rates. The impacts of different diluents (0.9 % saline and 5.0 % dextrose) and plastic syringes with or without silicone oil (SO) were also investigated. The results from the aforementioned particular case demonstrated that peristaltic pumps generated high levels of subvisible particles (prominently < 25 µm), exacerbated by increasing flow rates, specifically in formulations lacking surfactants. Other factors, such as diluent type and syringe composition, also increased the number of subvisible particles. Strategies that can help overcome these complications include surfactant addition as well as the use of SO-free syringes and a gravity infusion system, which aid in reducing particle formation and preserving antibody monomer during administration. Altogether, these findings highlight the importance of the careful selection of formulations and infusion protocols to minimize particle generation during IV infusion both for patients' safety and treatment efficacy.

A Novel Organoid-Based Strategy Using Hybrid Colon Interposition for Short Bowel Syndrome: A Mini Review of In Vivo Models and Possible Human Candidates.

This comprehensive review focuses on advances in surgical techniques and in vivo animal models for treating short bowel syndrome (SBS) with intestinal organoids. Notably, this review discusses a novel method involving the replacement of the epithelium of large intestinal tissue with small intestinal organoids, which improves function and prognosis when grafted back into the small intestine. This study not only underscores the importance of integrating organoid technology and surgical techniques to improve the outcomes of patients with SBS but also acknowledges the challenges that lie ahead, including achieving functional organoids with peristaltic movement and vascularization.

Effect of boundary slips and magnetohydrodynamics on peristaltic mechanism of Jeffrey nanofluid along with microorganisms through a porous medium.

The development on entropy generation in fluid flows has applications in many medical equipment such as cryogenic devices and therapeutic heat apparatus. This study looks at how porous medium, multi-slips, and entropy formation affect the pumping of Jeffrey nanofluid flow through an asymmetric channel containing motile microorganims. A lubrication theory is used to neglect the fluctuation effects in the flow. Numerical simulations are utilized to generate data for specific physical features of the problem utilizing the Shooting approach on Mathematica. Following a thorough research, it is appropriate to conclude that the porous medium's permeability reduces flow speed along the walls while increases at the center of the flow region. Graphical representation of the results further reveals that entropy production can be decreased by including high thermal slip and low viscous slip elements. It is also worth noting that the Brinkman number reduces the thermal distribution in the flow while it helps in increasing the flow speed.

Optogenetic techniques for understanding the gut peristalsis during chicken embryonic development.

Gut peristaltic movements transport ingested materials along the gut axis, which is critical for food digestion and nutrient absorption. While a large amount of studies have been devoted to analyzing the physiological functions of peristalsis in adults, little is known about how the peristaltic system is established during embryogenesis. In recent years, the chicken developing gut has emerged as an excellent model, in which specific sites along the gut axis can be genetically labeled enabling live imaging and optogenetic analyses. This review provides an overview of recent progress in optogenetic studies of gut peristalsis. Analyses with an improved channelrhodopsin-2 variant demonstrated that the peristalsis can artificially be generated in the developing gut. These studies unveiled novel functional coordination between different regions along the gut axis. In addition, imaging with GCaMP6s, a genetically encoded calcium indicator, enabled a fine mapping of developmental changes in the peristaltic patterns as Ca2+ signals. These advanced techniques will broaden our knowledge of how embryonic peristalsis is established at the cellular and molecular level, leading to the understanding of physiological and pathological processes in adult peristalsis.

Evaluation the kill rate and mutant selection window of danofloxacin against Actinobacillus pleuropneumoniae in a peristaltic pump model.

BACKGROUND: Actinobacillus pleuropneumoniae is a serious pathogen in pigs. The abundant application of antibiotics has resulted in the gradual emergence of drugresistant bacteria, which has seriously affected treatment of disease. To aid measures to prevent the emergence and spread of drug-resistant bacteria, herein, the kill rate and mutant selection window (MSW) of danofloxacin (DAN) against A. pleuropneumoniae were evaluated. METHODS: For the kill rate study, the minimum inhibitory concentration (MIC) was tested using the micro dilution broth method and time-killing curves of DAN against A. pleuropneumoniae grown in tryptic soy broth (TSB) at a series drug concentrations (from 0 to 64 MIC) were constructed. The relationships between the kill rate and drug concentrations were analyzed using a Sigmoid Emax model during different time periods. For the MSW study, the MIC99 (the lowest concentration that inhibited the growth of the bacteria by ≥ 99%) and mutant prevention concentration (MPC) of DAN against A. pleuropneumoniae were measured using the agar plate method. Then, a peristaltic pump infection model was established to simulate the dynamic changes of DAN concentrations in pig lungs. The changes in number and sensitivity of A. pleuropneumoniae were measured. The relationships between pharmacokinetic/pharmacodynamic parameters and the antibacterial effect were analyzed using the Sigmoid Emax model. RESULTS: In kill rate study, the MIC of DAN against A. pleuropneumoniae was 0.016 µg/mL. According to the kill rate, DAN exhibited concentration-dependent antibacterial activity against A. pleuropneumoniae. A bactericidal effect was observed when the DAN concentration reached 4-8 MIC. The kill rate increased constantly with the increase in DAN concentration, with a maximum value of 3.23 Log10 colony forming units (CFU)/mL/h during the 0-1 h period. When the drug concentration was in the middle part of the MSW, drugresistant bacteria might be induced. Therefore, the dosage should be avoided to produce a mean value of AUC24h/MIC99 (between 31.29 and 62.59 h. The values of AUC24h/MIC99 to achieve bacteriostatic, bactericidal, and eradication effects were 9.46, 25.14, and > 62.59 h, respectively. CONCLUSION: These kill rate and MSW results will provide valuable guidance for the use of DAN to treat A. pleuropneumoniae infections.

How to diagnose GERC more effectively: reflections on post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance.

INTRODUCTION: Post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI) are novel parameters reflect esophageal clearance capacity and mucosal integrity. They hold potential in aiding the recognition of gastroesophageal reflux-induced chronic cough (GERC). Our study aims to investigate their diagnostic value in GERC. METHODS: This study included patients suspected GERC. General information and relevant laboratory examinations were collected, and final diagnosis were determined following guidelines for chronic cough. The parameters of multichannel intraluminal impedance-pH monitoring (MII-pH) in patients were analyzed and compared to explore their diagnostic value in GERC. RESULTS: A total of 186 patients were enrolled in this study. The diagnostic value of PSPWI for GERC was significant, with the area under the working curve (AUC) of 0.757 and a cutoff value of 39.4%, which was not statistically different from that of acid exposure time (AET) (p > 0.05). The combined diagnostic value of AET > 4.4% and PSPWI < 39.4% was superior to using AET > 4.4% alone (p < 0.05). Additionally, MNBI and distal MNBI also contributed to the diagnosis of GERC, with AUC values of 0.639 and 0.624, respectively. AET > 4.4% or PSPWI < 39.4% is associated with a 44% reduction in missed diagnoses of non-acid GERC compared to AET > 6.0% or symptom association probability (SAP) ≥ 95%, and may be more favorable for identifying GERC. CONCLUSION: The diagnostic value of PSPWI for GERC is comparable to that of AET. Combining PSPWI < 39.4% or AET > 4.4% can improve the diagnostic efficiency by reducing the risk of missed diagnoses in cases where non-acid reflux is predominant. Distal MNBI and MNBI can serve as secondary reference indices in the diagnosis of GERC.

A Holistic Approach for Fill volume Variability Evaluation and Control with Statistical Tool.

Vial and syringe filling by peristaltic pump has been widely implemented by contract manufacturing organizations and biopharmaceutical companies. Fill volume is commonly considered as critical quality attribute related in aseptic filling process and the variation needs to be well controlled to guarantee the safety, efficacy and consistency of drug products. However, the criteria for justifying the filling variation and underlying mechanisms that affect the variability are not fully revealed quantitatively in the literatures. This study selected filling accuracy, filling process capability and filling precision as three criteria for evaluating the filling process performance with four statistical indexes: Relative Error Mean, Critical Control Limit (Cpk ≥ 1.33), Relative Standard Deviation and Relative Moving Range Mean. The impact of liquid properties, pump tubing sizes and pump settings on above indexes were investigated using a bench-top system with a peristatic pump and a high-precision balance. The results showed that the viscosity, target fill volume, pump tubing size, pump speed, acceleration/deceleration rate and suck-back had statistical significance on the fill volume variability. Definitive Screening Design was further applied to clarify and visualize the priorities and interaction impact of above factors on fill volume variability. Stepwise approach for fill volume variability optimization and control based on predictive models was established and verified for drug product solution with viscosity between 1-23 cp and target fill volume between 0.2-2.0 mL.

Mixed uncertainty analysis on pumping by peristaltic hearts using Dempster-Shafer theory.

In this paper, we introduce the numerical strategy for mixed uncertainty propagation based on probability and Dempster-Shafer theories, and apply it to the computational model of peristalsis in a heart-pumping system. Specifically, the stochastic uncertainty in the system is represented with random variables while epistemic uncertainty is represented using non-probabilistic uncertain variables with belief functions. The mixed uncertainty is propagated through the system, resulting in the uncertainty in the chosen quantities of interest (QoI, such as flow volume, cost of transport and work). With the introduced numerical method, the uncertainty in the statistics of QoIs will be represented using belief functions. With three representative probability distributions consistent with the belief structure, global sensitivity analysis has also been implemented to identify important uncertain factors and the results have been compared between different peristalsis models. To reduce the computational cost, physics constrained generalized polynomial chaos method is adopted to construct cheaper surrogates as approximations for the full simulation.

Saliva Production and Esophageal Motility Influence Esophageal Acid Clearance Related to Post-reflux Swallow-Induced Peristaltic Wave.

BACKGROUND: The post-reflux swallow-induced peristaltic wave (PSPW) brings salivary bicarbonate to neutralize residual distal esophageal mucosal acidification. AIMS: To determine if reduced saliva production and esophageal body hypomotility would compromise PSPW-induced pH recovery in the distal esophagus. METHODS: In this multicenter retrospective cross-sectional study, patients with confirmed Sjogren's syndrome and scleroderma/mixed connective tissue disease (MCTD) who underwent high resolution manometry (HRM) and ambulatory pH-impedance monitoring off antisecretory therapy were retrospectively identified. Patients without these disorders undergoing HRM and pH-impedance monitoring for GERD symptoms were identified from the same time-period. Acid exposure time, numbers of reflux episodes and PSPW, pH recovery with PSPW, and HRM metrics were extracted. Univariate comparisons and multivariable analysis were performed to determine predictors of pH recovery with PSPW. RESULTS: Among Sjogren's syndrome (n = 34), scleroderma/MCTD (n = 14), and comparison patients with reflux symptoms (n = 96), the scleroderma/MCTD group had significantly higher AET, higher prevalence of hypomotility, lower detected reflux episodes, and very low numbers of PSPW (p ≤ 0.004 compared to other groups). There was no difference in pH-impedance metrics between Sjogren's syndrome, and comparison patients (p ≥ 0.481). Proportions with complete pH recovery with PSPW was lower in Sjogren's patients compared to comparison reflux patients (p = 0.009), predominantly in subsets with hypomotility (p < 0.001). On multivariable analysis, diagnosis of Sjogren's syndrome, scleroderma/MCTD or neither (p = 0.014) and esophageal hypomotility (p = 0.024) independently predicted lack of complete pH recovery with PSPW, while higher total reflux episodes trended (p = 0.051). CONCLUSIONS: Saliva production and motor function are both important in PSPW related pH recovery.

Influence of inclined magnetic field and heat transfer on the peristaltic flow of Rabinowitsch fluid model in an inclined channel.

The recent study is focused on discussion of heat transfer and magnetic field results of peristaltic flow of Rabinowitsch fluid model in an Inclined Channel. In this piece of research, peristalsis's fundamental problem with heat transfer in the presence of a magnetic field is checked. An incompressible Rabinowitsch fluid is present in an inclined channel, which is considered as the reference for this research. The solutions are devised with the assumptions of long wavelength and low Reynolds number approximations. The resulting equations are then solved exactly by implementing various command of MATHEMATICA subject to relevant boundary conditions. Results are discussed for various flow quantities like temperature, velocity, tangential stress, pressure gradient and rise, and friction force. Computational simulations are performed to determine the flow quantities. This investigation goes beyond mere calculations and examines particle motion to gain deeper insights into flow quantities. Furthermore, this investigates how magnetic field and heat transfer parameters influence these peristaltic flow phenomena. The outcomes of important parameters were plotted and scrutinized. There is amultitude of medical implementations derived from the current consideration, such as the depiction of the gastric juice motion in the small intestine when an endoscope is inserted through it.

Supervised and unsupervised machine learning approaches for monitoring subvisible particles within an aluminum-salt adjuvanted vaccine formulation.

Suspensions of protein antigens adsorbed to aluminum-salt adjuvants are used in many vaccines and require mixing during vial filling operations to prevent sedimentation. However, the mixing of vaccine formulations may generate undesirable particles that are difficult to detect against the background of suspended adjuvant particles. We simulated the mixing of a suspension containing a protein antigen adsorbed to an aluminum-salt adjuvant using a recirculating peristaltic pump and used flow imaging microscopy to record images of particles within the pumped suspensions. Supervised convolutional neural networks (CNNs) were used to analyze the images and create "fingerprints" of particle morphology distributions, allowing detection of new particles generated during pumping. These results were compared to those obtained from an unsupervised machine learning algorithm relying on variational autoencoders (VAEs) that were also used to detect new particles generated during pumping. Analyses of images conducted by applying both supervised CNNs and VAEs found that rates of generation of new particles were higher in aluminum-salt adjuvant suspensions containing protein antigen than placebo suspensions containing only adjuvant. Finally, front-face fluorescence measurements of the vaccine suspensions indicated changes in solvent exposure of tryptophan residues in the protein that occurred concomitantly with new particle generation during pumping.

Impact of deep learning-based reconstruction and anti-peristaltic agent on the image quality and diagnostic performance of magnetic resonance enterography comparing single breath-hold single-shot fast spin echo with and without anti-peristaltic agent.

Background: While anti-peristaltic agents are beneficial for high quality magnetic resonance enterography (MRE), their use is constrained by potential side effects and increased examination complexity. We explored the potential of deep learning-based reconstruction (DLR) to compensate for the absence of anti-peristaltic agent, improve image quality and reduce artifact. This study aimed to evaluate the need for an anti-peristaltic agent in single breath-hold single-shot fast spin-echo (SSFSE) MRE and compare the image quality and artifacts between conventional reconstruction (CR) and DLR. Methods: We included 45 patients who underwent MRE for Crohn's disease between October 2021 and September 2022. Coronal SSFSE images without fat saturation were acquired before and after anti-peristaltic agent administration. Four sets of data were generated: SSFSE CR with and without an anti-peristaltic agent (CR-A and CR-NA, respectively) and SSFSE DLR with and without an anti-peristaltic agent (DLR-A and DLR-NA, respectively). Two radiologists independently reviewed the images for overall quality and artifacts, and compared the three images with DLR-A. The degree of distension and inflammatory parameters were scored on a 5-point scale in the jejunum and ileum, respectively. Signal-to-noise ratio (SNR) levels were calculated in superior mesenteric artery (SMA) and iliac bifurcation level. Results: In terms of overall quality, DLR-NA demonstrated no significant difference compared to DLR-A, whereas CR-NA and CR-A demonstrated significant differences (P<0.05, both readers). Regarding overall artifacts, reader 1 rated DLR-A slightly better than DLR-NA in four cases and rated them as identical in 41 cases (P=0.046), whereas reader 2 demonstrated no difference. Bowel distension was significantly different in the jejunum (Reader 1: P=0.046; Reader 2: P=0.008) but not in the ileum. Agreements between the images (Reader 1: ĸ=0.73-1.00; Reader 2: ĸ=1.00) and readers (ĸ=0.66 for all comparisons) on inflammation were considered good to excellent. The sensitivity, specificity, and accuracy in diagnosing inflammation in the terminal ileum were the same among DLR-NA, DLR-A, CR-NA and CR-A (94.42%, 81.83%, and 89.69 %; and 83.33%, 90.91%, and 86.21% for Readers 1 and 2, respectively). In both SMA and iliac bifurcation levels, SNR of DLR images exhibited no significant differences. CR images showed significantly lower SNR compared with DLR images (P<0.001). Conclusions: SSFSE without anti-peristaltic agents demonstrated nearly equivalent quality to that with anti-peristaltic agents. Omitting anti-peristaltic agents before SSFSE and adding DLR could improve the scanning outcomes and reduce time.

Post-reflux swallow-induced peristaltic wave index: a new parameter for the identification of non-acid gastroesophageal reflux-related chronic cough.

BACKGROUND: The current available diagnostic criteria for gastroesophageal reflux-related chronic cough (GERC) dominated by non-acid reflux is imperfect. The post-reflux swallow-induced peristaltic wave index (PSPWI) is a parameter reflecting esophageal clearance function. OBJECTIVES: This study aims to investigate its diagnostic value for non-acid GERC. DESIGN: This study sought to compare the diagnostic value of PSPWI in different types of GERC, particularly non-acid GERC, and explore the clinical significance of PSPWI in the diagnosis of non-acid GERC through diagnostic experiments. METHODS: A retrospective analysis was performed based on 223 patients with suspected GERC who underwent multichannel intraluminal impedance-pH monitoring (MII-pH) in the outpatient clinic of our department from August 2016 to June 2021. Their clinical information, laboratory test results, and treatment responses were assessed and the underlying etiologies of chronic cough were categorized. The predictive value of the PSPWI in diagnosing different types of GERC, especially non-acid GERC, was analyzed and compared. RESULTS: A total of 195 patients with chronic cough who met the inclusion criteria underwent MII-pH monitoring. 143 patients had a definitive diagnosis of GERC, including 98 with acid GERC and 45 with non-acid GERC. The diagnostic value of PSPWI alone was moderate for GERC with an area under the working curve (AUC) 0.760, but poor for non-acid GERC with an AUC of 0.569. However, PSPWI < 39.8% combining with acid exposure time (AET) ⩽ 6.2% demonstrated a moderate diagnostic value for non-acid GERC, with an AUC of 0.722. When PSPWI < 39.8% combined with a non-acid reflux ratio >68.75%, the diagnostic value for non-acid GERC was improved (AUCROC = 0.80 versus AUCROC = 0.722, p < 0.05), which was significantly superior to non-acid symptom index (AUCROC = 0.804 versus AUCROC = 0.550, p < 0.05) and non-acid symptom association probability (AUCROC = 0.804 versus AUCROC = 0.571, p < 0.05). CONCLUSION: PSPWI < 39.8% and AET ⩽ 6.2% have demonstrated good diagnostic value for non-acid GERC. The diagnostic value was further improved when combined with non-acid reflux ratio >68.75%.

Filling Unit Operation for Biological Drug Products: Challenges and Considerations.

One of the key unit operations during the aseptic fill-finish process of parenteral products, such as biologics, is the filling process of the formulated, sterile filtered drug substance into primary packaging containers. The applied filling technology as well as the process performance majorly impacts final drug product quality. The present review provides an overview of commonly used filling technologies during fill-finish operations of biologics including positive displacement pump systems such as radial peristaltic pump, rotary piston pump, rolling diaphragm pump, or innovative systems such as the linear peristaltic pump, as well as time-over-pressure filling technology. The article describes the operating principle of each pump system and reviews advantages and drawbacks. We highlight specific considerations for individual systems, such as the risk of protein particle formation and particle shedding from wear and tear of tubing, and discuss current literature about general challenges associated with the filling process, such as hydrogen peroxide uptake, adsorption phenomena to tubing material, and needle clogging. We suggest process development and process characterization studies to assess the impact of the filling process on product quality, and lastly provide an outlook about the use of disposable equipment during filling operations related to sustainability considerations.

Prospective comparison between a peristaltic pump and vacuum containers for paracentesis: Time, resources and safety.

RATIONALE AND OBJECTIVES: To meet the increasing demand for radiology departments to perform paracenteses, this study was done to compare the operational, financial and clinical impact of draining ascites with a peristaltic pump versus conventional vacuum containers. MATERIALS & METHODS: Prospective cohort study of 157 paracenteses (56 subjects) drained with ACCEL® evacuated drainage bottles (B. Braun Interventional Systems, Bethlehem, PA) and 159 paracenteses (53 subjects) drained with the RenovaRP® pump (Laborie Medical Technologies Corp., Portsmouth, NH). A short elective questionnaire was then distributed to the procedure staff and the subjects drained by both methods. RESULTS: Mean volume drained with the pump (5 L) was comparable to that drained by vacuum containers (4.9 L, p = 0.77). Mean time to drain subjects with the pump (18.6 min) was 9.1 min shorter and 3.8 min less variable than subjects drained with vacuum containers (27.7 min). This difference was statistically significant (p < 0.01) and clinically important (effect size = 0.73). Flow rate with the pump (4 min/L) was significantly faster (p < 0.05) than vacuum containers flow rate (6.6 min/L). No adverse events occurred in either group. Use of the pump increased the average cost by 21% and reduced earnings by 3%. All assistants (n = 6) and patients (n = 10) that responded to the questionnaire recommended the use of the pump over vacuum containers. CONCLUSION: The peristaltic pump safely drains ascites significantly faster and with less variability in time than vacuum containers. While use of the pump slightly increases cost per paracentesis, it was recommended by all paired subjects undergoing a paracentesis and all personnel assisting in the procedure.

Design, Simulation and Multi-Objective Optimization of a Micro-Scale Gearbox for a Novel Rotary Peristaltic Pump.

Peristaltic pumps are widely used in biomedical applications to ensure the safe flow of sterile or medical fluids. They are commonly employed for drug injections, IV fluids, and blood separation (apheresis). These pumps operate through a progressive contraction or expansion along a flexible tube, enabling fluid flow. They are also utilized in industrial applications for sanitary fluid transport, corrosive fluid handling, and novel pharmacological delivery systems. This research provides valuable insights into the selection and optimal design of the powertrain stages for peristaltic pumps implemented in drug delivery systems. The focus of this paper lies in the simulation and optimization of the performance of a power transmission gearbox by examining the energy consumption, sound levels, reliability, and volume as output metrics. The components of the powertrain consist of a helical gear pair for the first stage, a bevel gear pair for the second one, and finally a planetary transmission. Through extensive simulations, the model exhibits promising results, achieving an efficiency of up to 90%. Furthermore, alternative configurations were investigated to optimize the overall performance of the powertrain. This process has been simulated by employing the KISSsoft/KISSsys software package. The findings of this investigation contribute to advancements in the field of biomedical engineering and hold significant potential for improving the efficiency, reliability, and performance of drug delivery mechanisms.

Peristaltic motion of Jeffrey fluid with nonlinear mixed convection.

Since previous few decays the consideration of non-Newtonian liquids motion due to its immense usages in medicine, biology, industrial procedures, chemistry of catalysts and in environment. Various studies examine the significance of bio-materials flow in physiological procedures to explore the cure of diagnosed symptoms of disease appearing during movement in a human physiological system. To illustrate the characteristics of physiological liquids various non-Newtonian models have been proposed, but yet no such single liquid model is exploited which describes all the properties of nonlinear behaving liquids. Among these several non-Newtonian models, Jeffery liquid model should be reduced to its base fluid case (i.e. viscous liquid) by choosing λ1 = λ2 = 0. Various physiological materials which represents both linear and nonlinear characteristics respectively blood is one of these. Jeffery fluid and peristaltic motion have some common properties such as radii, relaxation time and retardation time. Moreover heat and mass transfer is also an important phenomenon which is suitable for various physiological processes such as hemodialysis and oxygenation etc. Thus due to such motivating facts this research is conducted to investigate the peristaltic motion of electrically conducting Jeffery liquid. The peristaltic propagating channel walls are asymmetric and inclined. Joule heating and magnetic field effects are considered by applying magnetic field in transverse direction to the flow. Further conservation laws modelled the flow situation via considering quadric mix convection, thermos diffusion and diffusion-thermos, heat generation and absorption, chemical reaction with activation energy features. Moreover, creeping flow and long wavelength assumptions are used to simplify the mathematical modelling. The reduced system of equation is solved numerically through built-in technique in Mathematica software. This built-in technique is working through ND Solve command and shooting and RK-Felburg numerical schemes are behind this technique. These numerical results are used to discuss the flow quantities i.e., velocity, temperature and concentration against the sundry dimensionless quantities. Examining the results it comes to know that both thermal and concentration nonlinear mix convection have oppositely affecting the axial velocity. Both heat and mass transfer are escalating function of thermo-diffusion/diffusion-thermo aspects.

The hydrodynamics and kinematics of the appendicularian tail underpin peristaltic pumping.

Planktonic organisms feed while suspended in water using various hydrodynamic pumping strategies. Appendicularians are a unique group of plankton that use their tail to pump water over mucous mesh filters to concentrate food particles. As ubiquitous and often abundant members of planktonic ecosystems, they play a major role in oceanic food webs. Yet, we lack a complete understanding of the fluid flow that underpins their filtration. Using high-speed, high-resolution video and micro particle image velocimetry, we describe the kinematics and hydrodynamics of the tail in Oikopleura dioica in filtering and free-swimming postures. We show that sinusoidal waves of the tail generate peristaltic pumping within the tail chamber with fluid moving parallel to the tail when filtering. We find that the tail contacts attachment points along the tail chamber during each beat cycle, serving to seal the tail chamber and drive pumping. When we tested how the pump performs across environmentally relevant temperatures, we found that the amplitude of the tail was invariant but tail beat frequency increased threefold across three temperature treatments (5°C, 15°C and 25°C). Investigation into this unique pumping mechanism gives insight into the ecological success of appendicularians and provides inspiration for novel pump designs.