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Perfluorocarbon Emulsions
Perfluorocarbon emulsions are emulsions containing either bubbles or droplets which have perfluorocarbons inside them. Some of them are commonly used in medicine as ultrasound contrast agents, and others have been studied for use as oxygen therapeutics. Ultrasound contrast agents The most common use of perfluorocarbon emulsions is as ultrasound contrast agents. In this application, microscopic bubbles containing perfluorocarbon gas are injected intravenously and flow through the bloodstream. An ultrasound machine then sends soundwaves through a tissue of interest, and the bubbles reflect the soundwaves to a greater extent than the surrounding tissues, thereby giving the blood greater contrast on ultrasound viewers. This can allow greater visibility of the structure of an organ of interest, or a better indication of the level of blood perfusion or blood volume in an area of interest. The bubbles persist in the blood stream with half-lives of minutes before the perfluorocarbon molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emulsions
An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms ''colloid'' and ''emulsion'' are sometimes used interchangeably, ''emulsion'' should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working. Two liquids can form different types of emulsions. As an example, oil and water can form, first, an oil-in-water emulsion, in which the oil is the dispersed phase, and water is the continuous phase. Second, they can form a water-in-oil emulsion, in which water is the dispersed phase and oil is the continuous phase. Multiple emulsions are also pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluorocarbons
Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often has distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Fluorocarbons and their derivatives are commercial polymers, refrigerants, drugs, and anesthetics. Nomenclature Perfluorocarbons or PFCs, are organofluorine compounds with the formula CxFy, i.e., they contain only carbon and fluorine. The terminology is not strictly followed and many fluorine-containing organic compounds are called fluorocarbons. Compounds with the prefix perfluoro- are hydrocarbons, including those with heteroatoms, wherein all C-H bonds have been replaced by C-F bonds. Fluorocarbons includes perfluoroalkanes, fluoroalkenes, fluoroalkynes, and perfluoroaromatic compounds. Perfluoroalkanes Chemical properties Perfluoroalkanes are very stable because of the strength of the carbon–fluorine bond, one of the strongest in organic chemistry. Its strength is a resu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebrospinal Fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the brain, and absorbed in the arachnoid granulations. There is about 125 mL of CSF at any one time, and about 500 mL is generated every day. CSF acts as a shock absorber, cushion or buffer, providing basic mechanical and immunological protection to the brain inside the skull. CSF also serves a vital function in the cerebral autoregulation of cerebral blood flow. CSF occupies the subarachnoid space (between the arachnoid mater and the pia mater) and the ventricular system around and inside the brain and spinal cord. It fills the ventricles of the brain, cisterns, and sulci, as well as the central canal of the spinal cord. There is also a connection from the subarachnoid space to the bony labyrinth of the inner ear via the perilymphat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen Cascade
In respiratory physiology, the oxygen cascade describes the flow of oxygen from air to mitochondria. Oxygen flows from areas with high partial pressure of oxygen (PO2, also known as oxygen tension) to areas of lower PO2. Air is typically around 21% oxygen, and at sea level, the PO2 of air is typically around 159 mmHg. Humidity dilutes the concentration of oxygen in air. As air is breathed into the lungs, it mixes with water and exhaust gasses including CO2, further diluting the oxygen concentration and lowering the PO2. As oxygen continues to flow from areas of higher concentration to lower concentration, it passes many barriers such as the alveoli, capillary walls, capillary plasma, red blood cell walls, interstitial space, other cell walls, and cell cytoplasm. The partial pressure of oxygen drops across each barrier. Table 1 gives the example of a typical oxygen cascade for a skeletal muscle of healthy, adult male at rest who is breathing air at atmospheric pressure. Actual valu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen–hemoglobin Dissociation Curve
The oxygen–hemoglobin dissociation curve, also called the oxyhemoglobin dissociation curve or oxygen dissociation curve (ODC), is a graph of a function, curve that plots the proportion of hemoglobin in its saturated (oxygen-laden) form on the vertical axis against the prevailing blood gas tension, oxygen tension on the horizontal axis. This curve is an important tool for understanding how our blood carries and releases oxygen. Specifically, the oxyhemoglobin dissociation curve relates oxygen saturation (SO2) and partial pressure of oxygen in the blood (PO2), and is determined by what is called "hemoglobin affinity for oxygen"; that is, how readily hemoglobin acquires and releases oxygen molecules into the fluid that surrounds it. Background Hemoglobin (Hb) is the primary vehicle for transporting oxygen in the blood. Each hemoglobin molecule has the capacity to carry four oxygen molecules. These molecules of oxygen bind to the Ferrous, iron of the heme prosthetic group. When h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
