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alpha

 [al´fah]
the first letter of the Greek alphabet, α; used to denote the first position in a classification system; as, in names of chemical compounds, to distinguish the first in a series of isomers, or to indicate the position of substituent atoms or groups; also used to distinguish types of radioactive decay, brain waves or rhythms, adrenergic receptors, and secretory cells that stain with acid dyes, such as the alpha cells of the pancreas.
alpha-adrenergic blocking agent (alpha-blocker) (alpha-blocking agent) any of a group of drugs that selectively inhibit the activity of alpha receptors in the sympathetic nervous system. As with beta-adrenergic blocking agents, alpha-blocking agents compete with the catecholamines at peripheral autonomic receptor sites. This group includes ergot and its derivatives, and phentolamine.
alpha chain disease the most common heavy chain disease, occurring predominantly in young adults in the Mediterranean area, and characterized by plasma cell infiltration of the lamina propria of the small intestine resulting in malabsorption with diarrhea, abdominal pain, and weight loss, or, exceedingly rarely, by pulmonary involvement. The gastrointestinal form is immunoproliferative small intestine disease.
alpha-fetoprotein (AFP) a plasma protein produced by the fetal liver, yolk sac, and gastrointestinal tract and also by hepatocellular carcinoma, germ cell neoplasms, and other cancers in adults; elevated levels may also be seen in benign liver disease such as cirrhosis and viral hepatitis. The serum AFP level is used to monitor the effectiveness of cancer treatment.

During pregnancy some AFP crosses from the amniotic fluid to the mother's blood. If the fetus has a neural tube defect, large amounts of AFP will be found in the amniotic fluid and maternal blood. Blood screening tests for serum AFP can thus be done as a first step in the screening process; if test results are positive, further testing is indicated to diagnose the defect.
alpha particles a type of emission produced by the disintegration of a radioactive substance. The atoms of radioactive elements such as uranium and radium are very unstable, continuously breaking apart with explosive violence and emitting particulate and nonparticulate types of radiation. The alpha particles, consisting of two protons and two neutrons, have an electrical charge and form streams of tremendous energy when they are released from the disintegrating atoms. These streams of energy (alpha rays) can be used in treatment of various malignancies. See also radiation and radiation therapy.

α

1. First letter of the Greek alphabet, alpha (α), used as a classifier in the nomenclature of many sciences.
3. In chemistry, denotes the first in a series, a position immediately adjacent to a carboxyl group, the first of a series of closely related compounds, an aromatic substituent on an aliphatic chain, or the direction of a chemical bond away from the viewer.
4. Abbreviation for alpha particle.
5. In chemistry, symbol for angle of optic rotation; degree of dissociation. For terms beginning with this prefix, see the specific term.

[α]


al·pha

(al'fă), The spelling alpha is used in chemical names, the spelling alfa in pharmaceutical names.
First letter of the Greek alphabet, α.

ALPHA

Abbreviation for:
Access to Learning for the Public Health Agenda (Medspeak-UK)
Agenda for Leadership in Programs for Healthcare Accreditation (obsolete)
Antenatal Psychosocial Health Assessment

α

Abbreviation for alpha.

al·pha

(α) (al'fă)
1. First letter of the Greek alphabet; used as a classifier in the nomenclature of many sciences.
3. chemistry Denotes the first in a series, a position immediately adjacent to a carboxyl group, the first of a series of closely related compounds, an aromatic substituent on an aliphatic chain, or the direction of a chemical bond away from the viewer.
4. Alpha (α) particle.
5. chemistry Symbol for angle of optic rotation; degree of dissociation.
References in periodicals archive ?
Depending on how you define the standards in measuring the alpha, the excess returns of a stock can change significantly from one benchmark to another.
As shown in table 1, comparing means of individuals with alpha deletion in beta-thai carriers, alpha deletion can modify mean of indices in beta thalassemia carriers slightly.
Marian Heath Griffin Alpha Kappa Alpha Baton Rouge, La.
The unconditional SDF alpha that is formed ignoring [Z.sub.t] is the unconditional mean of the conditional alphas, where the expectation is taken across the states.
In addition, the G-BOOK ALPHA DCM, a unique data communications module recently developed for G-BOOK ALPHA, employs innovative technology that substantially improves various communications functions, drastically improving data transmission speeds and enabling voice clarity with the same quality as car phones.
If alpha had changed since the original emission, the wavelengths emitted by oxygen ions on Earth today would differ slightly from those coming from the faraway galaxies.
An alpha contracting process requires a very high level of team dedication and long hours of work, both at home station and on the road.
Both earned $350 million in 2003, according to Alpha estimates.
About 175 members of the sorority belong to the Alpha Kappa Alpha Montgomery County Chapter, says Wilkinson, and more than 20 signed up for the original investment club, with members' ages ranging from 25 to 75.
"The Element-L Alpha Systems effectively lower the cost of entry into the Alpha market.
Brod suggested that an oral form of interferon alpha had some positive results in animals with EAE (a laboratory-induced MS-like disease).
(Also, [alpha] = 2/3 gives 1 - 27[C.sup.2]/44.) Continuing with this "zoo" of remarkable results (suggested largely by use of Wolfram Alpha), [alpha] = 1/4 gives 1-[G.sub.GA] [approximately equal to] 0.1653731583, where [G.sub.GA] is Gauss's constant, that is, the reciprocal of the arithmetic-geometric mean of 1 and [square root of 2], equalling [GAMMA][(1/4).sup.2]/2[square root of 3/2].