This article studies theoretically the transportation of rheological viscoplastic fluids through physiological vessels by continuous muscle contraction and relaxation, that is, peristalsis. Both cases of planar and cylindrical physiological vessels are considered. A mathematical model is developed under long wavelength and low Reynolds number approximations. Expressions for axial velocity in core region, axial velocity in plug flow region, volume flow rate and pressure gradient in non-dimensional form are obtained. A comparative study of velocity profiles, pressure distribution, friction force and mechanical efficiency for different viscoplastic liquids is conducted. The influence of width of plug flow region, shear rate strain index and yield stress index on the pressure distribution, friction force and mechanical efficiency is elaborated. The study is relevant to gastric fluid mechanics and also non-Newtonian biomimetic pump hazardous waste systems exploiting peristaltic mechanisms.
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http://dx.doi.org/10.1177/0954411913511584 | DOI Listing |
Cancer Res
January 2025
Swiss Federal Institute of technology in Lausanne, Lausanne, Vaud, Switzerland.
A recent publication by Bornes and colleagues explored the impact of the estrous cycle on mammary tumor response to neoadjuvant chemotherapy (NAC). Using genetically engineered mouse models, Bornes and colleagues revealed that chemotherapy is less effective when initiated during the diestrus stage compared to during the estrus stage. A number of changes during diestrous were identified that may reduce chemosensitivity of mammary tumors: an increased mesenchymal state of breast cancer cells during diestrous, decreased blood vessel diameters, and higher numbers of macrophages in the tumor microenvironment.
View Article and Find Full Text PDFIn Vitro Model
February 2024
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.
Unlabelled: Neuroblastoma (NB) is a highly vascularized pediatric tumor arising from undifferentiated neural crest cells early in life, exhibiting both traditional endothelial-cell-driven vasculature and an intriguing alternative vasculature. The alternative vasculature can arise from cancer cells undergoing transdifferentiation into tumor-derived endothelial cells (TEC), a trait associated with drug resistance and tumor relapse. The lack of effective treatments targeting NB vasculature primarily arises from the challenge of establishing predictive in vitro models that faithfully replicate the alternative vasculature phenomenon.
View Article and Find Full Text PDFExp Physiol
January 2025
Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK.
Fenestrated/branched endovascular aortic repair emerges as the primary therapeutic modality for intricate aortic pathologies encompassing the paravisceral and thoracoabdominal segments, where bridging stent grafts (BSGs) play a vital role in linking the primary aortic endograft with target vessels. Bridging stent grafts can be categorized mainly into self-expanding stent grafts (SESGs) and balloon-expandable stent grafts (BESGs). Physiological factors significantly influence post-complex endovascular aortic repair BSG behaviour, impacting clinical outcomes of SESGs and BESGs in different but overlapping ways.
View Article and Find Full Text PDFStem Cell Res Ther
January 2025
Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, Prince Philip Dental Hospital, The University of Hong Kong, 34 Hospital Road, Sai Ying Pun, Hong Kong, Hong Kong SAR.
Background: Achieving a stable vasculature is crucial for tissue regeneration. Endothelial cells initiate vascular morphogenesis, followed by mural cells that stabilize new vessels. This study investigated the in vivo effects of Sema4D-Plexin-B1 signaling on stem cells from human exfoliated deciduous teeth (SHED)-supported angiogenesis, focusing on its mechanism in PDGF-BB secretion.
View Article and Find Full Text PDFSci Rep
January 2025
Mechanical Engineering, Carnegie Mellon University, Pittsburgh, 15213, USA.
Local hemodynamics play an essential role in the initiation and progression of coronary artery disease. While vascular geometry alters local hemodynamics, the relationship between vascular structure and hemodynamics is poorly understood. Previous computational fluid dynamics (CFD) studies have explored how anatomy influences plaque-promoting hemodynamics.
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