The well known Fahraeus effect (1929) states that if whole blood is allowed to flow from a large reservoir into a small circular cylindrical tube, the hematocrit in the tube is smaller than that in the reservoir, and the smaller the tube, the smaller will be the tube hematocrit. This is interpreted as a feature of particulate flow. We find that this relationship is not monotonic in a model experiment in which gelatin particles (circular disks) are suspended in a silicone fluid to simulate blood. When the diameter of the underformed cell is equal to or greater than the tube diameter, the volume fraction of the cells in the tubes increases to a value equal to or greater than that in the reservoir. Thus the Fahraeus effect has a point of inversion. Additional experiments show that the hematocrit in the tube could be greatly influenced by the flow condition outside the entrance of the tube. If the tube is perpendicular to the main direction of flow in the reservoir (as is the case of Barbee and Cokelet's experiment, or in most arteriole-capillary junctions), the velocity gradient and the velocity of flow in the reservoir just outside the entrance to the tube affects the hematocrit in the tube.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1152/jappl.1977.42.4.578 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Comparative performance analysis of different microfilaria testing methods for Dirofilaria immitis in canine blood.
Parasit Vectors
November 2024
Department of Veterinary Pathobiology, Oklahoma State University College of Veterinary Medicine, Stillwater, OK, USA.
Article Synopsis
- Microfilaria (MF) testing is crucial for diagnosing canine heartworm, and the American Heartworm Society recommends annual testing for all dogs, regardless of their prevention history.
- Various MF testing methods exist, each differing in reliability, cost, and complexity; the study evaluates methods like the modified Knott test (MKT) and PCR, which are the most reliable but also more expensive and time-consuming.
- While the most reliable tests can identify heartworm even at low levels and confirm species, simpler tests like thin smears are less reliable, especially for accurate detection of MF-positive dogs at lower burdens.
Treatment of experimental hyperchloremic metabolic acidosis in horses with enteral electrolyte solution containing sodium acetate.
Front Vet Sci
September 2024
Laborary of Research in Veterinary Internal Medicine, Veterinary Department, Universidade Federal de Viçosa, Viçosa, Brazil.
Article Synopsis
- This study looks at a way to help horses that have a condition called hyperchloremic metabolic acidosis, which is when their body has too much acid.
- Researchers tested two different drinks for horses with varying amounts of a substance called acetate to see if they could fix the problem.
- The results showed that one drink with a high level of acetate worked well to balance the horses' electrolytes and help them feel better.
Comparative Analysis of Demographic Characteristics, Management, and Outcomes in Primary Versus Secondary Spontaneous Pneumothorax.
Cureus
July 2024
Cardiothoracic Surgery, Faculty of Medicine for Girls, Al-Azhar University, Cairo, EGY.
Objectives: This study aimed to explore the differences between primary spontaneous pneumothorax (PSP) and secondary spontaneous pneumothorax (SSP) in demographic and clinical features, management trends, and outcomes, alongside assessing recurrence risk factors in spontaneous pneumothorax (SP) patients.
Methods: This retrospective cohort study at New Damietta Hospital, Al-Azhar University, examined data from adults diagnosed with SP, differentiating between PSP and SSP types based on clinical and radiological criteria, to analyze demographics, clinical characteristics, management strategies, and outcomes.
Results: In a study of 170 patients, 42.
Relation between hematocrit partitioning and red blood cell lingering in a microfluidic network.
Biophys J
October 2024
ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
Despite increased interest in the effect of lingering red blood cells (LRBCs) on the heterogeneous hematocrit distribution in the microcirculation, quantitative data on LRBCs before and after the lingering event are still limited. The aim of the study was to investigate the relation between red blood cell (RBC) lingering and hematocrit partitioning in a microfluidic model of a microvascular bifurcation in the limit of low hematocrit conditions (tube hematocrit <10%). To this end, the classification of LRBCs was performed based on timing, position, and velocity of the RBCs.
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!