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Although stress response pathways are mediated in different ways depending on the stressor involved, cell type, etc., a general characteristic of many pathways – especially ones where heat is the principal stressor – is that they are initiated by the presence and detection of denatured proteins. Because conditions such as high temperatures ...
The heating effect varies with the power and the frequency of the electromagnetic energy, as well as the inverse square of distance to the source. The eyes and testes are particularly susceptible to radio frequency heating due to the paucity of blood flow in these areas that could otherwise dissipate the heat buildup. [7]
Heat shock proteins are also believed to play a role in the presentation of pieces of proteins (or peptides) on the cell surface to help the immune system recognize diseased cells. [22] The major HSPs involved in the HSR include HSP70, HSP90, and HSP60. [5] Chaperones include the HSP70s and HSP90s while HSP60s are considered to be chaperonins. [17]
The endothelium that lines blood vessels is known as vascular endothelium, which is subject to and must withstand the forces of blood flow and blood pressure from the cardiovascular system. To withstand these cardiovascular forces, endothelial cells must simultaneously have a structure capable of withstanding the forces of circulation while ...
The integrated stress response can be triggered within a cell due to either extrinsic or intrinsic conditions. Extrinsic factors include hypoxia, amino acid deprivation, glucose deprivation, viral infection and presence of oxidants. The main intrinsic factor is endoplasmic reticulum stress due to the accumulation of unfolded proteins.
The degree of heat and depth of penetration depend in part on the absorption of power as well as the electrical impedance of the current path between the electrodes, measured in ohms whose symbol is the Greek letter omega (Ω). Shortwave diathermy operations use ISM band frequencies of 4.00, 8.00, 13.56, 27.12, and 40.68 MHz.
A mature red blood cell has no mitochondria, [19] whereas a liver cell can have more than 2000. [ 20 ] [ 21 ] The mitochondrion is composed of compartments that carry out specialized functions. These compartments or regions include the outer membrane, intermembrane space , inner membrane , cristae , and matrix .
Optical scattering occurs due to mismatches in refractive index of the different tissue components, ranging from cell membranes to whole cells. Cell nuclei and mitochondria are the most important scatterers. [11] Their dimensions range from 100 nm to 6 μm, and thus fall within the NIR window.