natural purification (자정 작용
| oxazin dyes | Similar to azin dye's except that one of the connecting N atoms is replaced by O; most important representatives are brilliant cresyl blue, orcein, litmus, and cresyl violet. (05 Mar 2000) |
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| thiazin dyes | Similar to azin dye's except that one of the connecting N atoms is replaced by S; includes many important biological stains, especially in haematology, e.g., azure A, azure B, and methylene blue. (05 Mar 2000) |
| triphenylmethane dyes | A group of dye's that includes pararosanilin, as well as many others used in histology and cytology; employed as nuclear, cytoplasmic, and connective tissue stains; important in histochemistry as in the preparation of Schiff's reagent. (05 Mar 2000) |
| ketonimine dyes | Dye's in which the chromophore is ==C==NH connected to two benzene rings; alkylamino groups are added para to the methane carbon on both rings. The most important member for biological purposes is auramine O; an alternative formulation is as a diphenylmethane dye. (05 Mar 2000) |
| fluorescent dyes | Dyes that emit light when exposed to light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags. They are used as markers in biochemistry and immunology. (12 Dec 1998) |
| lissamine green dyes | Green dyes containing ammonium and aryl sulfonate moieties that facilitate the visualization of tissues, if given intravenously. They have mostly been used in the study of kidney physiology. (12 Dec 1998) |
| conservation of natural resources | The protection, preservation, restoration, and rational use of all resources in the total environment. (12 Dec 1998) |
| natural | 1. Fixed or determined by nature; pertaining to the constitution of a thing; belonging to native character; according to nature; essential; characteristic; not artifical, foreign, assumed, put on, or acquired; as, the natural growth of animals or plants; the natural motion of a gravitating body; natural strength or disposition; the natural heat of the body; natural colour. "With strong natural sense, and rare force of will." (Macaulay) 2. Conformed to the order, laws, or actual facts, of nature; consonant to the methods of nature; according to the stated course of things, or in accordance with the laws which govern events, feelings, etc.; not exceptional or violent; legitimate; normal; regular; as, the natural consequence of crime; a natural death. "What can be more natural than the circumstances in the behavior of those women who had lost their husbands on this fatal day?" (Addison) 3. Having to do with existing system to things; dealing with, or derived from, the creation, or the world of matter and mind, as known by man; within the scope of human reason or experience; not supernatural; as, a natural law; natural science; history, theology. "I call that natural religion which men might know . By the mere principles of reason, improved by consideration and experience, without the help of revelation." (Bp. Wilkins) 4. Conformed to truth or reality; as: Springing from true sentiment; not artifical or exaggerated; said of action, delivery, etc.; as, a natural gesture, tone, etc. Resembling the object imitated; true to nature; according to the life; said of anything copied or imitated; as, a portrait is natural. 5. Having the character or sentiments properly belonging to one's position; not unnatural in feelings. "To leave his wife, to leave his babes, . He wants the natural touch." (Shak) 6. Connected by the ties of consanguinity. "Natural friends." 7. Begotten without the sanction of law; born out of wedlock; illegitimate; bastard; as, a natural child. 8. Of or pertaining to the lower or animal nature, as contrasted with the higher or moral powers, or that which is spiritual; being in a state of nature; unregenerate. "The natural man receiveth not the things of the Spirit of God." (1 Cor. Ii. 14) 9. <mathematics> Belonging to, to be taken in, or referred to, some system, in which the base is 1; said or certain functions or numbers; as, natural numbers, those commencing at 1; natural sines, cosines, etc, those taken in arcs whose radii are 1. 10. Produced by natural organs, as those of the human throat, in distinction from instrumental music. Of or pertaining to a key which has neither a flat nor a sharp for its signature, as the key of C major. Applied to an air or modulation of harmony which moves by easy and smooth transitions, digressing but little from the original key. Natural day, the space of twenty-four hours. Natural fats, Natural gas, etc. See Fat, Gas. Etc. Natural Harmony, a classification based upon real affinities, as shown in the structure of all parts of the organisms, and by their embryology. "It should be borne in mind that the natural system of botany is natural only in the constitution of its genera, tribes, orders, etc, and in its grand divisions." (Gray) Natural theology, or Natural religion, that part of theological science which treats of those evidences of the existence and attributes of the Supreme Being which are exhibited in nature; distinguished from revealed religion. See Quotation under Natural. Natural vowel, the vowel sound heard in urn, furl, sir, her, etc.; so called as being uttered in the easiest open position of the mouth organs. See Neutral vowel. Synonym: See Native. Origin: OE. Naturel, F. Naturel, fr. L. Naturalis, fr. Natura. See Nature. Source: Websters Dictionary (01 Mar 1998) |
| natural antibody | Antibody demonstrable in the serum or plasma of various persons or animals not known to have been stimulated by specific antigen, either artificially or as the result of naturally occurring contact. Synonym: natural antibody. (05 Mar 2000) |
| natural childbirth | Psychophysical relaxation techniques that are used to facilitate childbirth. (12 Dec 1998) |
| natural classification | <zoology> Classification based on inferences concerning the phylogenetic relationships of animals. (09 Jan 1998) |
| natural dentition | See: dentition. (05 Mar 2000) |
| natural disasters | Sudden calamitous events producing great material damage, loss, and distress. They are the result of natural phenomena such as earthquakes, floods, etc. (12 Dec 1998) |
| natural focus of infection | An ecosystem in which an infectious agent normally persists in nature; e.g., yellow fever virus in a jungle monkey-Haemagogus mosquito ecosystem. (05 Mar 2000) |
| natural haemolysin | Haemolysin occurring in the plasma of an animal of one species, e.g., a dog, which fixes complement with the red blood cells of some other species, e.g., a rabbit, thereby causing haemolysis of the cells of the rabbit, although the dog was not previously exposed to antigenic stimulation with such cells. (05 Mar 2000) |