| 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) |
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| 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) |
| back pain, low | Symptoms in the low back can relate to the bony lumbar spine, discs between the vertebrae, ligaments around the spine and discs, spinal cord and nerves, muscles of the low back, internal organs of the pelvis and abdomen, and the skin covering the lumbar area. The low back, or lumbar area, functions in structural support, movement, and protection of certain body tissue. (12 Dec 1998) |
| blood sugar, low | The sugar here is glucose. Low blood glucose constitutes hypoglycaemia. Hypoglycaemia is only significant when it is associated with symptoms. It has many causes including drugs, liver disease, surgical absence of the stomach, pre-diabetes, and rare tumours that release excess insulin. (12 Dec 1998) |
| cardiac output, low | A state of subnormal or depressed cardiac output, usually seen in patients with heart failure secondary to coronary artery, hypertensive, primary myocardial, valvular, or pericardial disease. (12 Dec 1998) |
| very low density lipoprotein | <biochemistry> A lipoprotein substances (combination of a fat and a protein) which acts as a carrier for cholesterol and fats (particularly triglycerides) in the bloodstream. Elevations in very low density lipoprotein in the bloodstream are associated with an increased risk of atherosclerosis and coronary artery disease. Acronym: VLDL (18 Nov 1997) |
| Castellani-Low sign | <clinical sign> A fine tremor of the tongue observed in sleeping sickness. (05 Mar 2000) |
| mean lower low water | <marine biology> The average height of the lower low waters over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year value. (09 Oct 1997) |
| mean low water | <marine biology> The average height of the low waters over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year value. All low-water heights are included in the average where the type of tide is either semidiurnal or mixed. Only the lower low-water heights are included in the average where the type of tide is diurnal. So determined, mean low water in the latter case is the same as mean lower low water. (09 Oct 1997) |
| placenta, low | Location of the placenta in the lower part of the uterus (womb) so that the placenta partially or completely covers the cervix. Also known as a placenta previa. (12 Dec 1998) |
| ear, low-set | A minor anomaly involving an ear situated down below its normal location. Technically, the ear is low-set when the helix (of the ear) meets the cranium at a level below that of a horizontal plane through both inner canthi (the inside corners of the eyes). The presence of 2 or more minor anomalies in a child increases the probability that the child has a major malformation. (12 Dec 1998) |