Reactive oxygen species (ROS) are ions or very small molecules that include oxygen ions, free radicals, and peroxides, both inorganic and organic. They are highly reactive due to the presence of unpaired valence shell electrons. ROS form as a natural byproduct of the normal metabolism of oxygen and have important roles in cell signaling. However, during times of environmental stress, ROS levels can increase dramatically, which can result in significant damage to cell structures.
Photomultiplier tubes (photomultipliers or PMTs, for short)—members of the class of vacuum tubes and more specifically phototubes—are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. These detectors multiply the current produced by incident light by as much as 100 million times, in multiple dynode stages, enabling individual photons to be detected when the incident flux of light is very low.
Seminal fluid is the fluid that is emitted from the male reproductive tract and that contains sperm cells, which are capable of fertilizing the female eggs.
Dyspnea—or shortness of breath (SOB)—is a debilitating symptom that is the experience of unpleasant or uncomfortable respiratory sensations. It is a common symptom of numerous medical disorders, particularly those involving the cardiovascular and respiratory systems.
Oxidizability is the susceptibility of a substance to be oxidized.
In chemistry, radicals (often referred to as free radicals) are atoms, molecules, or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions. They may damage proteins, DNA, lipids, and cell membranes.
Lipid peroxidation refers to the oxidative degradation of lipids. It is the process whereby free radicals "steal" electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical chain reaction mechanism.
Oxidative stress is caused by an imbalance between the production of reactive oxygen and a biological system's ability to readily detoxify the reactive intermediates or to easily repair the resulting damage. All forms of life maintain a reducing environment within their cells. This reducing environment is preserved by enzymes that maintain the reduced state through a constant input of metabolic energy. Disturbances in this normal redox state can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress is a key factor in many diseases.
Thermochemiluminescence (TCL), or Chemiluminesence, is the emission of light with limited emission of heat (luminescence), as the result of a chemical reaction.
Congestive Heart Failure (HF) or Heart Failure (HF) is a condition in which a problem with the structure or function of the heart impairs its ability to supply sufficient blood flow to meet the body's needs. Common causes of heart failure include myocardial infarction and other forms of ischemic heart disease, hypertension, valvular heart disease, and cardiomyopathy.
In vitro fertilization (IVF) is a process by which egg cells are fertilized by sperm outside the womb, in vitro. IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed.