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Biodegradable and Biocompatible Polymer Composite
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Lothar Kroll, Lightweight Polymer Composite Structures, 2020
Naga Srilatha Cheekuramelli, Dattatraya Late, S. Kiran, Baijayantimala Garnaik
However, in interactions of materials with human blood, the materials should be capable of resisting blood cell adhesion and absorption of protein, which lead to triggering of organisms’ defense system [45]. Researchers have introduced three kinds of polymeric surfaces [45,46], such as 1. micro-phase separation surface domains, 2. biomembranes-based materials, 3. hydrophilicity-induced surfaces. These surfaces instigated physicochemical activities such as stiffness, surface-charge, wettability surface free energy, topography attributes to the induced chemical functionalities which are recommended to the implementation of these materials in biomedical devices [45,47]. Blood-compatibility- and biocompatibility-induced poly(2-methoxyethyl acrylate) (PEMA) is also an excellent material for implanted applications and it has been approved in food-administration and medical drug applications [46,48,49]. PEMA-coated tubes were recently used in biomedical applications due to their reduced blood cell-activation when it is implemented in catheters for central veins and cardiopulmonary bypass. Moreover, PEMA’s compatibility with platelet interaction elucidates coagulation, which is the most preeminent characteristics for the biomedical implanted applications [50].
Elements of Continuum Mechanics
Published in Clement Kleinstreuer, Biofluid Dynamics, 2016
Apart from a patch where it is connected to the diaphragm, the liver is covered entirely by a thin, double-layered membrane that reduces friction against other organs. Based on surface appearance, it can be divided into major folded lobes (see Fig. 4.3.1a). Surprisingly, there are only two types of cells forming the structure of the liver. The liver cells, called hepatocytes, form hepatic plates that are one to two cell-layers thick. These plates are separated by microchannels, called sinusoids (see Fig. 4.3.1b). The channel walls are lined with Kupffer cells which, like white blood cells, can “devour” toxins, bacteria, etc. As indicated in Fig. 4.3.1a, nutrients in the blood from the digestive system are carried via the hepatic partial vein to capillaries in the liver, as it receives arterial blood via the hepatic artery. The hepatic plates are arranged into active units called liver lobules, each with a central vein which collects the arterial/venous blood mixture flowing through the sinusoids (Fig. 4.3.1b). The central veins of all the lobules converge and deliver the blood to the inferior vena cava. In contrast, bile is produced by the hepatocytes and secreted into microchannels, called bile canaliculi, which empty into the bile duct (see Fig. 4.3.1).
The effects of a high-fat diet on the liver of pregnant albino rats and their developing offspring
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Abdelalim A. Gadallah, Abdullah R. Almasari
In the current work, severe histopathological signs were recorded in the liver of HFD mother rats and their fetuses included dilated blood sinusoids, congested central veins and excess Kupffer cells. Similar observations were recorded by [31], who found that exposure of female rats to HFD during gestation is implicated in the induction of severe liver cell injury and development of hepatic steatosis. Further investigation by TEM revealed remarkable deleterious changes in the cellular levels of hepatic cells like abnormal canaliculi, atrophied and swollen mitochondria, dilated rough endoplasmic reticulum, damaged microvilli, and accumulated lipid droplets. Previous reports have declared that exposure to HFD during gestation and lactation periods is implicated in induction of oxidative stress on the liver cells even in mothers or their offspring, resulting in liver cell damage [32,33]. Additionally, the offspring of HFD mothers rats were accompanied by liver mitochondrial DNA (mtDNA) damage, as reported by [34]. Such finding agrees with our obtained results.
Modified electrode placements for measurement of hemodynamic parameters using impedance cardiography
Published in Journal of Medical Engineering & Technology, 2020
Vu Duy Hai, Phan Dang Hung, Chu Quang Dan
The configuration of electrode placement generally accepted in ICG technique is the 8-spot electrode configuration proposed by Bernstein [12]. The standard position of electrodes is placed as Figure 1. Each dual electrode includes a pair of pads to inject current and measure voltage signal simultaneously. The distance between these pads in one pair is fixed. For the upper part, two electrodes are positioned to each side of the patient’s neck. The lower pads of the electrodes are placed at the root of the neck. For the lower part, the two remaining electrodes are applied on each side of the thorax along the mid-axillary line. The upper pad of the sensor is positioned closest to the heart at the level of the Xiphoid point [13]. However, intravenous catheterisation is usually indicated for most patients admitted to an intensive care unit, and central venous catheterisation is used in case of impracticality to use peripheral venous cannulation [14]. In the United State more than 5 million central venous catheterizations are conducted each year [15]. The central venous catheterisation is usually indicated to access for giving drugs, access for extracorporeal blood circuits, and hemodynamic monitoring and interventions [16]. The most common positions to insert catheters at proximal central veins are the internal jugular, subclavian, or femoral vein [16]. The two positions frequently selected are subclavian and internal jugular sites due to their lower risk of infection and fewer mechanical complication [17].
Overview of the safety and efficacy of the Surfacer® Inside-Out® Access Catheter System for obtaining central venous access in patients with thoracic central venous obstructions
Published in Expert Review of Medical Devices, 2020
Alternative approaches for the placement of catheters in patients with exhausted central veins are possible [Table 2], but are associated with an increase in adverse events including insertion-related complications and reduced catheter survival [7,25,26]. Catheter placement via a femoral vein is a commonly used alternative in dialysis patients with occluded upper body central veins. This placement location has been shown to be associated with shorter primary patency compared to catheters placed via the RIJ and an increased risk of ipsilateral lower extremity deep vein thrombosis [25–27]. Other catheter placement procedures sometimes utilized in this patient population include placement via transhepatic or translumbar approaches or direct atrial puncture [7]. These procedures are more difficult to perform than conventional catheter placement, with insertion-related complications specific to the anatomy associated with each procedure.