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Microfluidic Contact Lenses for Ocular Diagnostics
Published in Raju Khan, Chetna Dhand, S. K. Sanghi, Shabi Thankaraj Salammal, A. B. P. Mishra, Advanced Microfluidics-Based Point-of-Care Diagnostics, 2022
Antonysamy Dennyson Savariraj, Ammar Ahmed Khan, Mohamed Elsherif, Fahad Alam, Bader AlQattan, Aysha. A. S. J. Alghailani, Ali K. Yetisen, Haider Butt
Continuous monitoring of ocular surface temperature (OST) is helpful to review ocular conditions such as glaucoma, vascular neuritis, diabetic retinopathy, carotid artery stenosis, and dry eye disease (DED). The positive correlation observed between body temperature and ocular temperature (Purslow and Wolffsohn 2005) and between ocular temperature difference values (TDVs) and dry eye parameters suggest that OST monitoring is important to obtain POC ocular diagnostics. OST increase observed in patients with meibomian gland dysfunction (MGD) (Terada et al. 2004), phakic and pseudophakic (Sniegowski et al. 2015) psychiatric disorders (Monge-Roffarello et al. 2014, Tan et al. 2009) in post-corneal transplant undergoing inflammation (Sniegowski et al. 2018), and dogs with keratoconjunctivitis sicca (Biondi et al. 2015) further evidences for the necessity for the measurement of OST to monitor disease progression in personalized diagnostics (Moreddu et al. 2019).
Nanotechnologies Assemblies of siRNA and Chemotherapeutic Drugs Codelivered for Cancer Therapeutic Applications
Published in Loutfy H. Madkour, Nanoparticle-Based Drug Delivery in Cancer Treatment, 2022
Vascular inflammation is also implicated in atherosclerosis and the clinical problem of intimal hyperplasia following vascular grafting and stent placement. Intimal hyperplasia is characterized by invasion of the vessel lumen by smooth muscle cells and is a primary cause of graft/stented vessel stenosis and failure. Therapeutic-eluting stent coatings to modulate the inflammatory response and cell proliferation within the stent can reduce rates of stent failure, and siRNA strategies merit investigation in this application [141].
Cardiovascular system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Two more relatively common congenital cardiology treatments are for coarctation of the aorta and pulmonary artery stenosis. Each of these is treated by placing a (relatively large) stent within the obstruction. An aortic coarctation is often a very significant stenosis, around the superior aspect of the descending thoracic aorta. This can be so severe as to make passage of a catheter quite challenging. Once a stiff wire has been passed via the femoral artery and through the stenosis, pressure measurements are taken on either side of the coarctation. The difference in peak proximal to distal pressure is known as a pressure gradient. Once an appropriately sized stent has been deployed, the pressure gradient is again measured to check the value of the treatment. If not significantly reduced, the stent may be dilated using a larger balloon.
Hemodynamic study in 3D printed stenotic coronary artery models: experimental validation and transient simulation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Violeta Carvalho, Nelson Rodrigues, Ricardo Ribeiro, Pedro F. Costa, José C. F. Teixeira, Rui A. Lima, Senhorinha F. C. F. Teixeira
In this study, idealized stenotic coronary arteries were studied by applying numerical and experimental approaches. At laminar conditions, the results were found to be in close agreement proving the accuracy of the numerical model by its validation. After those observations, a single-phase numerical model, combined with a pulsatile inlet condition, was used to investigate the effect of DOS in velocity and WSS indice measurements. Overall, the results have shown that higher the DOS, greater the WSS and velocity reached within the stenotic section with the appearance of recirculation zones. Moreover, low WSS and high OSI values are responsible for the creation or progression of the atherosclerotic plaque. Hence, the blood flow behavior and hemodynamic indicators are significantly affected by the presence of stenosis, where the 70% stenotic situation has proved to be an extremely severe case which can lead to acute cardiovascular events. Additionally, from the comparison of single and multiphase approaches, it was concluded that for low flow rates the differences are insignificant and, therefore, can be neglected.
Unsteady biomedical investigation of nano-fluid flow via a bent stenosed blood vessel (with aneurysm) using the Sisko model
Published in Waves in Random and Complex Media, 2022
The cardiovascular system – sometimes also called the circulatory system – comprises a complex system of vessels spread across the human body, and the heart pumps in/out blood into the vessels. These vessels consist of countless arteries, veins, and tiny capillaries, which receive oxygenated blood containing various nutrients & hormones required for human survival. Simultaneously, the human cells put metabolic waste products like Carbon Dioxide (CO2) into the blood which returns them through the veins and heart into the lungs for disposal. In this way, the cardiovascular system maintains blood inside every body cell to allow it to survive [1]. However, in some situations, an atypical narrowing of the blood vessels occurs due to the amassing of redundant fatty deposits within the lumen. This narrowing of vessels is known as stenosis, which takes place in the lesion of vessel walls. In some other cases, these deposits ensue in the bulging of vessel walls, which are called aneurysms. Commonly, both stenosis and aneurysms coexist inside the vessel walls and contribute to their increased volume sizes with the passage of time. It is now acknowledged through recent literature that the advancement in the size of stenosis is tightly related to the malfunctions in the blood transport to various body parts. It is also evident that the rate of blood flow is highly influenced in smaller arteries due to the presence of the shear stress of the wall that leads to the constriction formations or bulging inside the vessel walls. Moore et al. [2] pointed out that the enlargement of post-stenotic or aneurysm normally occurs in the coronary arteries. Later, Sultan et al. [3] discussed the simultaneous effect of aneurysms and stenosis in a curved channel. Based on this discussion, it is evident that the behavior of blood flow is affected in an artery by stenosis or aneurysm and, therefore, should be further explored. The experimental data reveal that most of the malfunctions that occurred in the cardiovascular system are normally located in an unbent channel. Therefore, this work is devoted to exploring the hemodynamic effects on the flow of blood through a curved stenosed vessel.