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Scientific Reports Jan 2023Robotic locomotion in subterranean environments is still unsolved, and it requires innovative designs and strategies to overcome the challenges of burrowing and moving...
Robotic locomotion in subterranean environments is still unsolved, and it requires innovative designs and strategies to overcome the challenges of burrowing and moving in unstructured conditions with high pressure and friction at depths of a few centimeters. Inspired by antagonistic muscle contractions and constant volume coelomic chambers observed in earthworms, we designed and developed a modular soft robot based on a peristaltic soft actuator (PSA). The PSA demonstrates two active configurations from a neutral state by switching the input source between positive and negative pressure. PSA generates a longitudinal force for axial penetration and a radial force for anchorage, through bidirectional deformation of the central bellows-like structure, which demonstrates its versatility and ease of control. The performance of PSA depends on the amount and type of fluid confined in an elastomer chamber, generating different forces and displacements. The assembled robot with five PSA modules enabled to perform peristaltic locomotion in different media. The role of friction was also investigated during experimental locomotion tests by attaching passive scales like earthworm setae to the ventral side of the robot. This study proposes a new method for developing a peristaltic earthworm-like soft robot and provides a better understanding of locomotion in different environments.
Topics: Animals; Oligochaeta; Robotics; Locomotion; Friction; Peristalsis
PubMed: 36709355
DOI: 10.1038/s41598-023-28873-w -
Gastroenterology Clinics of North... Mar 2013Although conventional manometry set the basis for the diagnosis of esophageal motility disorders, the large axial spacing between recording sites leaves large portions... (Review)
Review
Although conventional manometry set the basis for the diagnosis of esophageal motility disorders, the large axial spacing between recording sites leaves large portions of the esophagus unevaluated and vulnerable to movement artifact. However, continuous spatiotemporal representations of pressure through the esophagus recorded with high-resolution manometry offers greater detail and improved accuracy for many of the most important measurements of esophageal motor function. This review describes how the new classification schemes for esophageal pressure topography have evolved from conventional criteria and focuses on how esophageal pressure topography has improved the ability to subcategorize conventional manometric diagnoses into new functional phenotypes.
Topics: Esophageal Achalasia; Esophageal Spasm, Diffuse; Humans; Manometry; Peristalsis; Pressure
PubMed: 23452627
DOI: 10.1016/j.gtc.2012.11.001 -
Neurogastroenterology and Motility Jan 2020The contractile activity of Jackhammer esophagus(JE) is heterogeneous and abnormalities in the balance of pre- and post-peak contractile activity has been reported. We...
BACKGROUND
The contractile activity of Jackhammer esophagus(JE) is heterogeneous and abnormalities in the balance of pre- and post-peak contractile activity has been reported. We observed that the progression of the peak contraction is disordered in JE patients, which reflect underlying abnormalities in the inhibitory and excitatory influence in esophageal contraction. In order to better define this abnormality, we developed novel time metrics to define trajectory of the pressure wave peak and assessed it in healthy controls and JE patients.
METHODS
38 patients with JE (ages 43-70, 19 females) and 71 asymptomatic controls (ages 19-48; 33 females) were retrospectively evaluated. High resolution manometry was performed in all subjects with 10 supine liquid swallows. The first 5 intact supine swallows and supine swallow with the greatest DCI were analyzed using ManoView™ software and customized MATLAB program. The time distance, negative time distance sum and chaotic ratio were calculated. JE patients were subcategorized by the Brief Esophageal Dysphagia Questionnaire (BEDQ) with cut-off of 6.
KEY RESULTS
Jackhammer patients had longer time distance, longer negative time distance, and higher chaotic ratio than controls( p < 0.001). The distribution of the number of negative time distances differed between JE patients with BEDQ>6 and BEDQ≤6.
CONCLUSIONS & INFERENCES
The trajectory of the pressure wave peak propagation commonly occurred in an unordered fashion in JE, but rarely in controls. Additionally, differences in pressure propagation trajectory was associated with higher symptom scores thus trajectory of the pressure wave peak may be an important marker of abnormal esophageal motor function.
Topics: Adult; Aged; Deglutition; Esophageal Motility Disorders; Female; Humans; Male; Manometry; Middle Aged; Muscle Contraction; Peristalsis
PubMed: 31532046
DOI: 10.1111/nmo.13725 -
Gut Apr 1995Secondary peristalsis contributes to oesophageal acid clearance. The aim of the study was to evaluate the integrity and characteristics of secondary peristalsis in...
Secondary peristalsis contributes to oesophageal acid clearance. The aim of the study was to evaluate the integrity and characteristics of secondary peristalsis in patients with gastro-oesophageal reflux disease. Studies were performed in 22 patients with reflux disease and 20 age matched controls. Oesophageal motility was recorded at 3 cm intervals along the oesophageal body. Primary peristalsis was tested with 5 ml water swallows. Secondary peristalsis was stimulated with 10 ml boluses of air and water injected in the mid-oesophagus and by 5 second distensions with a 3 cm balloon at the same level. It was found that primary peristalsis was normal in 19 of 20 control subjects and in 14 of 22 patients with reflux disease. In patients with reflux disease, intact secondary peristalsis was triggered infrequently by air and water distension (median success rate of 0% for both stimuli) and occurred significantly less frequently than in control subjects (50% and 30% respectively). The frequency of balloon induced secondary peristalsis, however, was similar in the two groups (0% controls, 20% reflux disease). The major pattern of failure of secondary peristalsis was the complete absence of any oesophageal secondary peristaltic response. The amplitudes of the intact secondary peristaltic responses were not significantly different for the two groups. Peristaltic velocity for air and balloon induced secondary peristalsis was also similar in control subjects and patients with reflux disease whereas water induced secondary peristalsis was slower in the reflux patients. In conclusion, patients with reflux disease exhibit a pronounced defect in the triggering of secondary peristalsis.
Topics: Adult; Aged; Aged, 80 and over; Air; Catheterization; Deglutition; Drinking; Esophagus; Female; Gastroesophageal Reflux; Humans; Male; Manometry; Middle Aged; Peristalsis
PubMed: 7737553
DOI: 10.1136/gut.36.4.499 -
Journal of the Royal Society, Interface Sep 2020Most biological functional systems are complex, and this complexity is a fundamental driver of diversity. Because input parameters interact in complex ways, a holistic...
Most biological functional systems are complex, and this complexity is a fundamental driver of diversity. Because input parameters interact in complex ways, a holistic understanding of functional systems is key to understanding how natural selection produces diversity. We present uncertainty quantification (UQ) as a quantitative analysis tool on computational models to study the interplay of complex systems and diversity. We investigate peristaltic pumping in a racetrack circulatory system using a computational model and analyse the impact of three input parameters (Womersley number, compression frequency, compression ratio) on flow and the energetic costs of circulation. We employed two models of peristalsis (one that allows elastic interactions between the heart tube and fluid and one that does not), to investigate the role of elastic interactions on model output. A computationally cheaper surrogate of the input parameter space was created with generalized polynomial chaos expansion to save computational resources. Sobol indices were then calculated based on the generalized polynomial chaos expansion and model output. We found that all flow metrics were highly sensitive to changes in compression ratio and insensitive to Womersley number and compression frequency, consistent across models of peristalsis. Elastic interactions changed the patterns of parameter sensitivity for energetic costs between the two models, revealing that elastic interactions are probably a key physical metric of peristalsis. The UQ analysis created two hypotheses regarding diversity: favouring high flow rates (where compression ratio is large and highly conserved) and minimizing energetic costs (which avoids combinations of high compression ratios, high frequencies and low Womersley numbers).
Topics: Algorithms; Heart; Peristalsis; Uncertainty
PubMed: 32900306
DOI: 10.1098/rsif.2020.0232 -
Neurogastroenterology and Motility Jan 2022This study aimed to systematically evaluate a classification scheme of secondary peristalsis using functional luminal imaging probe (FLIP) panometry through comparison...
BACKGROUND AND AIMS
This study aimed to systematically evaluate a classification scheme of secondary peristalsis using functional luminal imaging probe (FLIP) panometry through comparison with primary peristalsis on high-resolution manometry (HRM).
METHODS
706 adult patients that completed FLIP and HRM for primary esophageal motility evaluation and 35 asymptomatic volunteers ("controls") were included. Secondary peristalsis, that is, contractile responses (CRs), was classified on FLIP panometry by the presence and pattern of contractility as normal (NCR), borderline (BCR), impaired/disordered (IDCR), absent (ACR), or spastic-reactive (SRCR). Primary peristalsis on HRM was assessed according to the Chicago Classification.
RESULTS
All 35 of the controls had antegrade contractions on FLIP panometry with either NCR (89%) or BCR (11%). The average percentages of normal swallows on HRM varied across contractile response patterns from 84% in NCR, 68% in BCR, 39% in IDCR, to 11% in ACR, as did the percentage of failed swallows on HRM: 4% in NCR, 12% in BCR, 36% in IDCR, and 79% in ACR. SRCR on FLIP panometry was observed in 18/57 (32%) patients with type III achalasia, 4/15 (27%) with distal esophageal spasm, and 7/15 (47%) with hypercontractile esophagus on HRM.
CONCLUSIONS
The FLIP panometry contractile response patterns reflect a pathophysiologic transition from normal to abnormal esophageal peristaltic function with shared features with primary peristaltic function/dysfunction on HRM. Thus, these patterns of the contractile response to distension can facilitate the evaluation of esophageal motility using FLIP panometry.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Deglutition; Esophageal Motility Disorders; Esophagogastric Junction; Esophagus; Female; Humans; Male; Manometry; Middle Aged; Peristalsis; Young Adult
PubMed: 34120383
DOI: 10.1111/nmo.14192 -
Scientific Reports Feb 2023The key objective of the current examination is to examine a symmetrically peristaltic movement of microorganisms in a Rabinowitsch fluid (RF). The Boussinesq...
The key objective of the current examination is to examine a symmetrically peristaltic movement of microorganisms in a Rabinowitsch fluid (RF). The Boussinesq approximation, buoyancy-driven flow, where the density with gravity force term is taken as a linear function of heat and concentrations, is kept in mind. The flow moves with thermophoretic particle deposition in a horizontal tube with peristalsis. The heat distribution and volume concentration are revealed by temperature radiation and chemical reaction characteristics. The originality of the existing study arises from the importance of realizing the benefits or the threats that nanoparticles, microbes, and bacteria cause in the flow inside peristaltic tubes. The results are an attempt to understand what factors perform additional advantages and or reduce damages. The controlling nonlinear partial differential equations (PDEs) are made simpler by employing the long wavelength (LWL) and low-Reynolds numeral (LRN) approximations. These equations are subjected to a set of non-dimensional transformations that result in a collection of nonlinear ordinary differential equations (ODEs). By employing the Homotopy perturbation method (HPM), the configuration of equational analytical solutions is examined. Analytical and graphical descriptions are provided for the distributions of axial speed, heat, microbes, and nanoparticles under the influence of these physical characteristics. The important findings of the current work may help to comprehend the properties of several variations in numerous biological situations. It is found that the microorganisms condensation decays with the rise of all the operational parameters. This means that the development of all these factors benefits in shrinking the existence of harmful microbes, viruses, and bacteria in the human body's peristaltic tubes, especially in the digestive system, and large and small intestines.
Topics: Humans; Models, Biological; Peristalsis; Temperature; Nanoparticles; Hot Temperature
PubMed: 36725906
DOI: 10.1038/s41598-023-28967-5 -
The Journal of Thoracic and... Dec 2020
Topics: Esophagus; Humans; Lung Transplantation; Peristalsis; Transplants
PubMed: 32417061
DOI: 10.1016/j.jtcvs.2020.02.124 -
World Journal of Gastroenterology Mar 2007The morphology of tissue structures composing the pyloric orifice is thought to play a role in effectively mixing aqueous gastric effluent with duodenal secretions. To... (Review)
Review
The morphology of tissue structures composing the pyloric orifice is thought to play a role in effectively mixing aqueous gastric effluent with duodenal secretions. To understand the physical mechanisms leading to efficient digestion requires computational models that allow for analyses of the contributions of individual structural components. Thus, we have simulated 2-D channel flows through representative models of the duodenum with moving boundary capabilities in order to quantitatively assess the importance of notable features. A well-tested flow solver was used to computationally isolate and compare geometric and kinematic parameters that lead to various characteristics of fluid motion at the antroduodenal junction. Scalar variance measurement was incorporated to quantify the mixing effectiveness of each component. It was found that the asymmetric geometry of the pyloric orifice in concert with intermittent gastric outflow and luminal constriction is likely to enhance homogenization of gastric effluent with duodenal secretions.
Topics: Biomechanical Phenomena; Computer Simulation; Duodenum; Gastrointestinal Motility; Humans; Mathematics; Models, Biological; Peristalsis; Pyloric Antrum; Viscosity
PubMed: 17457967
DOI: 10.3748/wjg.v13.i9.1365 -
American Journal of Physiology.... Jun 2009Gastric emptying depends on functional coupling of slow waves between the corpus and antrum, to allow slow waves initiated in the gastric corpus to propagate to the...
Gastric emptying depends on functional coupling of slow waves between the corpus and antrum, to allow slow waves initiated in the gastric corpus to propagate to the pyloric sphincter and generate gastric peristalsis. Functional coupling depends on a frequency gradient where slow waves are generated at higher frequency in the corpus and drive the activity of distal pacemakers. Simultaneous intracellular recording from corpus and antrum was used to characterize the effects of PGE(2) on slow waves in the murine stomach. PGE(2) increased slow-wave frequency, and this effect was mimicked by EP(3), but not by EP(2), receptor agonists. Chronotropic effects were due to EP(3) receptors expressed by intramuscular interstitial cells of Cajal because these effects were not observed in W/W(V) mice. Although the integrated chronotropic effects of EP(3) receptor agonists were deduced from electrophysiological experiments, no clear evidence of functional uncoupling was observed with two-point electrical recording. Gastric peristalsis was also monitored by video imaging and spatiotemporal maps to study the impact of chronotropic agonists on propagating contractions. EP(3) receptor agonists increased the frequency of peristaltic contractions and caused ectopic sites of origin and collisions of peristaltic waves. The impact of selective regional application of chronotropic agonists was investigated by use of a partitioned bath. Antral slow waves followed enhanced frequencies induced by stimulation of the corpus, and corpus slow waves followed when slow-wave frequency was elevated in the antrum. This demonstrated reversal of slow-wave propagation with selective antral chronotropic stimulation. These studies demonstrate the impact of chronotropic agonists on regional intrinsic pacemaker frequency and integrated gastric peristalsis.
Topics: Alprostadil; Animals; Biological Clocks; Dibenz(b,f)(1,4)oxazepine-10(11H)-carboxylic acid, 8-chloro-, 2-acetylhydrazide; Dinoprostone; Membrane Potentials; Mice; Mice, Inbred BALB C; Mice, Mutant Strains; Muscle, Smooth; Peristalsis; Prostaglandins; Prostaglandins E, Synthetic; Pyloric Antrum; Receptors, Prostaglandin E; Receptors, Prostaglandin E, EP1 Subtype; Receptors, Prostaglandin E, EP2 Subtype; Receptors, Prostaglandin E, EP3 Subtype; Stomach
PubMed: 19359421
DOI: 10.1152/ajpgi.90724.2008