| models, biological | Theoretical representations that simulate the behaviour or activity of biological processes or diseases. For disease models in living animals, disease models, animal is available. Biological models include the use of mathematical equations, computers, and other electronic equipment. (12 Dec 1998) |
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| collision cross-section | <radiobiology> Effective surface area of a particle when it collides with another, describes probability of collisions between the two particles. (09 Oct 1997) |
| pituitary stalk section | Transection of the neurovascular connection between the hypothalamus and the pituitary gland. (05 Mar 2000) |
| plastic section stain | <technique> For electron microscopy, a stain (e.g., osmic acid, PTA, potassium permanganate) used on thin sections of plastic-embedded tissues, utilizing differential attachment of heavy atoms to various cellular and tissue structures so that electrons will be absorbed and scattered by these structures to produce an image; to achieve differential staining, the stain must penetrate nonwettable plastic embedments, for light microscopy, a stain (e.g., alkaline toluidine blue, silver methenamine) used on plastic-embedded tissues to attain higher resolution and more detail than normally possible; semi-thick (0.5-1.5 um) sections are particularly useful in renal pathology, especially in combination with the phase microscope. (05 Mar 2000) |
| coronal section | A cross section attained by slicing, actually or through imaging techniques, the body or any part of the body or any anatomic structure in the coronal or frontal plane, i.e., in a vertical plane perpendicular to the median or sagittal plane. Since actual sectioning in the coronal plane results in an anterior and a posterior portion, an anatomical coronal section may be a two-dimensional view of the cut surface of the posterior aspect of the anterior portion, or of the anterior aspect of the posterior portion. Synonym: frontal section. (05 Mar 2000) |
| cross-section | <physics> Usually refers to the (apparent) area presented by a target particle to an oncoming particle (or electromagnetic wave). This measures the probability of an interaction occuring. For typical interactions between ions and electrons, or between two nuclei, these cross sections are generally measured in barns. <anatomy> A transverse cut through a structure or tissue. The opposite of a cross-section is a longitudinal section. By analogy, a study may be cross-sectional or longitudinal. (12 Dec 1998) |
| C-section | A surgical procedure that involves the delivery of the foetus through an abdominal incision. C-sections account for about 1/5 of all births in the us. Indications include: failure to progress, foetal distress, cephalopelvic disproportion (baby's too big for birth canal), placenta previa, placental abruption, placental insufficiency, breech baby, active genital herpes, multiple gestation, preeclampsia and excessive scarring from previous surgeries. The average hospital stay is about 4 days. The maternal death rate with C-section is three times higher than with natural delivery. (27 Sep 1997) |
| cull section | A log cut from a tree that is rejected because of defects making it unsuitable for conventional forest products. (05 Dec 1998) |
| Saemisch's section | Procedure of transfixing the cornea beneath an ulcer and then cutting from within outward through the base. (05 Mar 2000) |
| sagittal section | A cross section obtained by slicing, actually or through imaging techniques, the body or any part of the body, or any anatomic structure in the sagittal plane, i.e., in a vertical plane parallels to the median plane. Since actual sectioning in the sagittal plane results in a right and a left portion, an anatomical sagittal section may be a two-dimensional view of the cut surface on the medial aspect of either portion. Synonym: parasagittal section. (05 Mar 2000) |
| section | 1. The act of cutting, or separation by cutting; as, the section of bodies. 2. A part separated from something; a division; a portion; a slice. Specifically: A distinct part or portion of a book or writing; a subdivision of a chapter; the division of a law or other writing; a paragraph; an article; hence, the character, often used to denote such a division. "It is hardly possible to give a distinct view of his several arguments in distinct sections." (Locke) A distinct part of a country or people, community, class, or the like; a part of a territory separated by geographical lines, or of a people considered as distinct. "The extreme section of one class consists of bigoted dotards, the extreme section of the other consists of shallow and reckless empirics." (Macaulay) One of the portions, of one square mile each, into which the public lands of the United States are divided; one thirty-sixth part of a township. These sections are subdivided into quarter sections for sale under the homestead and preemption laws. 3. <geometry> The figure made up of all the points common to a superficies and a solid which meet, or to two superficies which meet, or to two lines which meet. In the first case the section is a superficies, in the second a line, and in the third a point. 4. A division of a genus; a group of species separated by some distinction from others of the same genus; often indicated by the sign . 5. A part of a musical period, composed of one or more phrases. See Phrase. 6. The description or representation of anything as it would appear if cut through by any intersecting plane; depiction of what is beyond a plane passing through, or supposed to pass through, an object, as a building, a machine, a succession of strata; profile. In mechanical drawing, as in these Illustrations of a cannon, a longitudinal section (a) usually represents the object as cut through its center lengthwise and vertically; a cross or transverse section (b), as cut crosswise and vertically; and a horizontal section (c), as cut through its center horizontally. Oblique sections are made at various angles. In architecture, a vertical section is a drawing showing the interior, the thickness of the walls, ets, as if made on a vertical plane passed through a building. <mathematics> Angular sections, an instrument to aid in drawing a series of equidistant parallel lines, used in representing sections. Thin sections, a section or slice, as of mineral, animal, or vegetable substance, thin enough to be transparent, and used for study under the microscope. Synonym: Part, portion, division. Section, Part. The English more commonly apply the word section to a part or portion of a body of men; as, a section of the clergy, a small section of the Whigs, etc. In the United States this use is less common, but another use, unknown or but little known in England, is very frequent, as in the phrases "the eastern section of our country," etc, the same sense being also given to the adjective sectional as, sectional feelings, interests, etc. Origin: L. Sectio, fr. Secare, sectum, to cut; akin to E. Saw a cutting instrument: cf. F. Section. See Saw, and cf. Scion, Dissect, Insect, Secant, Segment. Source: Websters Dictionary (01 Mar 1998) |
| section, caesarian | Procedure in which an infant, rather than being born vaginally, is surgically removed from the uterus. As the name caesarian suggests, this is not a new procedure. It was done in ancient civilizations upon the death of a pregnant woman near term to salvage the baby. Julius caesar (or, more likely, one of his predecessors) was born by this procedure. The term section in surgery refers to the division of tissue. What is being divided here is the abdominal wall of the mother and the wall of the uterus in order to extract the baby. In shakespeare's macbeth the witches' prophecy was that..none of woman born/ shall harm macbeth (iv.i). Unfortunately for macbeth, the scottish nobleman macduff was from his mother's womb/ untimely ripped. And thus not naturally born of woman (v.vii). Macduff is the only agent capable of destroying macbeth. He kills macbeth in battle. (12 Dec 1998) |
| section, cross | A transverse cut through a structure. The opposite is a longitudinal section. (12 Dec 1998) |
| section, longitudinal | A cut along the long axis of a structure. (12 Dec 1998) |
| section, lower segment cesarian | A Cesarian section in which the surgical incision (cut) is made in the lower segment of the uterus. (12 Dec 1998) |