| molecular probes | A group of atoms or molecules attached to other molecules or cellular structures and used in studying the properties of these molecules and structures. Radioactive DNA or RNA sequences are used in molecular genetics to detect the presence of a complementary sequence by molecular hybridization. (12 Dec 1998) |
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| molecular probe techniques | The use of devices which use detector molecules to detect, investigate, or analyze other molecules, macromolecules, molecular aggregates, or organisms. (12 Dec 1998) |
| molecular sequence data | Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as genbank, european molecular biology laboratory (embl), national biomedical research foundation (nbrf), or other sequence repositories. (12 Dec 1998) |
| molecular sieve | A gel-like material with pore sizes of such ranges as to exclude molecules above certain sizes; used in fractionating or purifying macromolecules. (05 Mar 2000) |
| molecular structure | The location of the atoms, groups or ions relative to one another in a molecule, as well as the number and location of chemical bonds. (12 Dec 1998) |
| directed molecular evolution | Techniques used to produce molecules exhibiting properties that conform to the demands of the experimenter. (12 Dec 1998) |
| epidemiology, molecular | The application of molecular biology to the answering of epidemiological questions. The examination of patterns of changes in DNA to implicate particular carcinogens and the use of molecular markers to predict which individuals are at highest risk for a disease are common examples. (12 Dec 1998) |
| european molecular biology lab gene bank | <molecular biology> A large database of DNA sequence data in Heidelberg, Germany, compiled from international sources. It is the European equivalent to the Genbank DNA sequence databank in the United States of America. WWW: EMbase. (09 Oct 1997) |
| evolution, molecular | Evolution at the molecular level of DNA sequences and proteins. (rieger et al., glossary of genetics: classical and molecular, 5th ed) (12 Dec 1998) |
| kinetic molecular theory | <chemistry> This theory assumes that molecules must collide in order to react. The more collisions the more likely it is for a reaction to occur. However, depending on the conditions, only a small fraction of the collisions are effective in producing a reaction. There are several constraints. In order for a reaction to occur, bonds initially are broken, which requires energy. This energy depends on the type of the reaction and comes from the kinetic energies that the molecules possess before the collision. It is called the activation energy. Increasing the temperature increases the kinetic energies and more collisions will occur. In adition, at a higher temperature a greater number of the reacting molecules might possess an energy equal to or greater than the activation energy. However the molecules must also collide in a specific orientation, called the steric factor in order for a reaction to occur. A reaction will only be successful, if the collision has enough energy to be either equal to or greater than the activation energy and if the orientation of the collision allows for correct bond formation. These factors are in the Arrhenius equation: k = zp The rate constant k is proportional to the Arrhenius factor A. A is the product of the collision frequency z, and the steric factor p. The fraction of collisions with sufficient energy to produce a reaction are in the term of the equation. (09 Jan 1998) |
| blood pressure, high | High blood pressure (hypertension) is a repeatedly elevated blood pressure exceeding 140 over 90 mmHg. High blood pressure is also called the silent killer. Chronically high blood pressure can cause blood vessel changes in the back of the eye (retina), thickening of the heart muscle, kidney failure, and brain damage. No specific cause for high blood pressure is found in 95% of patients. High blood pressure is treated with salt restriction, regular aerobic exercise, and medications. (12 Dec 1998) |
| blood sugar, high | Elevated levels of blood glucose (hyperglycaemia) can be found in a number of conditions. The hyperglycaemia leads to spillage of glucose into the urine, hence the term sweet urine. (Diabetes mellitus means sweet urine. ) (12 Dec 1998) |
| cardiac output, high | A state of elevated cardiac output. Conditions that lower peripheral vascular resistance, such as anaemia, arteriovenous fistulas, thyrotoxicosis, and pregnancy, are among the most important factors augmenting the venous return and therefore elevating cardiac output. Increased cardiac output also occurs in muscular exercise, fever, and severe anoxia. (12 Dec 1998) |
| radiotherapy, high-energy | Radiotherapy using high-energy (megavolt or higher) ionizing radiation. Types of radiation include gamma rays, produced by a radioisotope within a teletherapy unit; X-rays, electrons, protons, alpha particles (helium ions) and heavy charged ions, produced by particle acceleration; and neutrons and pi-mesons (pions), produced as secondary particles following bombardment of a target with a primary particle. (12 Dec 1998) |
| mean higher high water | <marine biology> The average height of the higher high water over a 19-year period. For shorter periods of observation, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year value. (09 Oct 1997) |