The purpose of this study was to measure stresses associated with turbulence (Reynolds stresses), in the region of a 29-mm-dia porcine bioprosthetic valve (Hancock, Model 242). Studies were performed in an in vitro pulse duplicating system with the valve mounted in the aortic position. The Reynolds stresses were calculated from velocities obtained with a two channel laser Doppler anemometer. The largest Reynolds shear stress and normal stress occurred at the highest stroke volume used (80 mL). Averaged over ejection they were 38 dynes/cm2 and 380 dynes/cm2, respectively. The maximal instantaneous Reynolds shear stress was 2500 dynes/cm2 and the maximal instantaneous Reynolds normal stress was 6800 dynes/cm2. Stresses of these magnitudes are in the range reported to damage platelets.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1115/1.3138544 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Unveiling the toxicity of micro-nanoplastics: A systematic exploration of understanding environmental and health implications.
Toxicol Rep
June 2025
Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur 56000, Malaysia.
The surge in plastic production has spurred a global crisis as plastic pollution intensifies, with microplastics and nanoplastics emerging as notable environmental threats. Due to their miniature size, these particles are ubiquitous across ecosystems and pose severe hazards as they are ingested and bioaccumulate within organisms. Although global plastic production has reached an alarming 400.
View Article and Find Full Text PDFLeaf nitrogen and phosphorus are more sensitive to environmental factors in dicots than in monocots, globally.
Plant Divers
November 2024
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China.
Leaf nitrogen (N) and phosphorus (P) levels provide critical strategies for plant adaptions to changing environments. However, it is unclear whether leaf N and P levels of different plant functional groups (e.g.
View Article and Find Full Text PDFInjection of ROS-Responsive Hydrogel Loaded with IL-1β-targeted nanobody for ameliorating myocardial infarction.
Bioact Mater
April 2025
School of Medicine South China University of Technology, Guangzhou, Guangdong, 510006, China.
The cardiac microenvironment profoundly restricts the efficacy of myocardial regeneration tactics for the treatment of myocardial infarction (MI). A prospective approach for MI therapeutics encompasses the combined strategy of scavenging reactive oxygen species (ROS) to alleviate oxidative stress injury and facilitating macrophage polarization towards the regenerative M2 phenotype. In this investigation, we fabricated a ROS-sensitive hydrogel engineered to deliver our previously engineered IL-1β-VHH for myocardial restoration.
View Article and Find Full Text PDFMelatonin induces drought stress tolerance by regulating the physiological mechanisms, antioxidant enzymes, and leaf structural modifications in L.
Heliyon
January 2025
Department of Horticulture, Muhammad Nawaz Shareef University of Agriculture, Multan, 66000, Pakistan.
Melatonin is considered an effective bio-stimulant that is crucial in managing several abiotic stresses including drought. However, its potential mechanisms against drought stress in fragrant roses are not well understood. Here, we aim to investigate the role of melatonin on plants cultivated under drought stress (40 % field capacity) and normal irrigation (80 % field capacity).
View Article and Find Full Text PDFDid the Covid-19 Pandemic Impact Time to Surgery, Length of Hospital Stay, or Discharge Location for Subaxial Cervical Spine Fractures Requiring Surgical Intervention?
Iowa Orthop J
January 2025
UBMD Orthopaedics and Sports Medicine Doctors, Buffalo, New York, USA.
Background: The COVID-19 pandemic disrupted healthcare systems across the United States resources were consumed caring for COVID-19 patients. Past research on trauma activations during COVID-19 has found changes to hospital length of stay and discharge locations. Subaxial spine fractures are potentially debilitating injuries that require timely surgery and extensive rehabilitation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!