| nuclei originis | Collections of motor neurons (forming a continuous column in the spinal cord, discontinuous in the medulla and pons) giving origin to the spinal and cranial motor nerves. Synonym: nuclei originis, motor nuclei. (05 Mar 2000) |
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| nuclei parabrachiales | The cell groups flanking the brachium conjunctivum at levels immediately caudal to the inferior colliculus; they serve as way-stations in the pathways ascending from the nucleus of solitary tract to the thalamus and hypothalamus, and receive afferent fibres from the hypothalamus and amygdaloid body. Synonym: nuclei parabrachiales. (05 Mar 2000) |
| nuclei pontis | The massive gray matter filling the basilar pons. The nuclei are of fairly homogeneous architecture and project to the cortex of the contralateral cerebellar hemisphere by way of the middle cerebellar peduncle. Their main afferents come from the entire extent of the cerebral neocortex by way of the longitudinal pontine bundles (corticopontine fibres); thus, the pontine nuclei form a major way-station in the impulse conduction from the cerebral cortex of one hemisphere to the posterior lobe of the opposite cerebellum. Synonym: nuclei pontis, pontine gray matter. (05 Mar 2000) |
| nuclei raphes | Collections of small neurons centrally scattered among many fibres from the level of the trochlear nucleus in the midbrain to the hypoglossal area in the medulla oblongata. (12 Dec 1998) |
| nuclei tegmenti | Collective term for two small round cell groups in the caudal part of the midbrain (caudal pontine tegmental nucleus, nucleus tegmenti pontis caudalis and oral pontine tegmental nucleus, nucleus tegmenti pontis oralis), associated with the mamillary body by way of the mamillary peduncle and mamillotegmental tract. Synonym: nuclei tegmenti, Gudden's tegmental nuclei. (05 Mar 2000) |
| nuclei terminationis | Tetracyclic steroid nucleus, the group of four fused rings forming the framework or parent substance of the steroids. Synonym: perhydrocyclopenta[a]phenanthrene, steroid nucleus, terminal nuclei. (05 Mar 2000) |
| nuclei tuberales | Two or three small, encapsulated, round or ovoid clusters of cells in the lateral hypothalamic area along the surface of the tuber cinereum; their connections and functional significance are unknown. Synonym: nuclei tuberales, lateral tuberal nuclei. (05 Mar 2000) |
| nucleic acid | <biochemistry, molecular biology> Linear polymers of nucleotides, linked by 3', 5' phosphodiester linkages. In DNA, deoxyribonucleic acid, the sugar group is deoxyribose and the bases of the nucleotides adenine, guanine, thymine and cytosine. RNA, ribonucleic acid, has ribose as the sugar and uracil replaces thymine. DNA functions as a stable repository of genetic information in the form of base sequence. RNA has a similar function in some viruses but more usually serves as an informational intermediate (mRNA), a transporter of amino acids (tRNA), in a structural capacity or, in some newly discovered instances, as an enzyme. The spontaneous loss of the amino groups of cytosine (yielding uracil), methyl cytosine (yielding thymine) or of adenine (yielding hypoxanthine). It can be argued that the presence of thymine in DNA in place of the uracil of RNA stabilises genetic information against this lesion, since repair enzymes would restore the GU base pair to GC. (18 Nov 1997) |
| nucleic acid base | A purine or pyrimidine; found in naturally occurring nucleic acids such as DNA. (05 Mar 2000) |
| nucleic acid conformation | The characteristic 3-dimensional shape of a nucleic acid or polynucleotide. Its secondary structure is due to the formation of hydrogen bonds between nucleotides, resulting in base pairing and areas with alpha helix structure. (12 Dec 1998) |
| nucleic acid denaturation | Disorganization of secondary structures of nucleic acids through cleavage of hydrogen bonds and hydrophobic linkages. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible. (12 Dec 1998) |
| nucleic acid heteroduplexes | Double-stranded nucleic acid molecules (DNA-DNA or DNA-RNA) which contain regions of nucleotide mismatches (non-complementary). In vivo, these heteroduplexes can result from mutation or genetic recombination; in vitro, they are formed by nucleic acid hybridization. Electron microscopic analysis of the resulting heteroduplexes facilitates the mapping of regions of base sequence homology of nucleic acids. (12 Dec 1998) |
| nucleic acid hybridization | Widely used technique which exploits the ability of complementary sequences in single-stranded dnas or rnas to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (kendrew, encyclopedia of molecular biology, 1994, p503; dorlands, 28th ed, p781) (12 Dec 1998) |
| nucleic acid precursors | Use for nucleic acid precursors in general or for which there is no specific heading. (12 Dec 1998) |
| nucleic acid probe | A nucleic acid fragment, labelled by a radioisotope, biotin, etc., that is complementary to a sequence in another nucleic acid (fragment) and that will, by hydrogen binding to the latter, locate or identify it and be detected; a diagnostic technique based on the fact that every species of microbe possesses some unique nucleic acid sequences which differentiate it from all others, and thus can be used as identifying markers or "fingerprints." (05 Mar 2000) |
Synonyms : Amplification Technics, Nucleic Acid, Amplification Techniques, Nucleic Acid, DNA Amplification Technics, Nucleic Acid Amplification Technics, RNA Amplification Technics, Technics, Nucleic Acid Amplification, Techniques, Nucleic Acid Amplification
Synonyms : Conformation, Nucleic Acid, Conformations, Nucleic Acid, Nucleic Acid Conformations
Synonyms : Acid Denaturation, Nucleic, Denaturation, DNA, Denaturation, Nucleic Acid, Denaturation, RNA, Nucleic Acid Denaturations
Synonyms : Heteroduplex DNA, Acid Heteroduplexes, Nucleic, DNA, Heteroduplex
Synonyms : Acid Hybridization, Nucleic, Acid Hybridizations, Nucleic, Genomic Hybridizations, Hybridization, Genomic, Hybridization, Nucleic Acid, Hybridizations, Genomic, Hybridizations, Nucleic Acid, Nucleic Acid Hybridizations
| nucleoli |
In biology, the nucleolus is, strictly speaking, a "suborganelle" of the cell nucleus, which is an organelle. Only plant and animal nuclei have nucleoluses. Most plant and animal cells have one or more nucleoluses although some do not. No membrane separates the nucleolus from the nucleoplasm. The nucleolus are made of protein and ribonucleic acid (RNA) and contains proteins as well as ribosomal RNA. ...
출처: en.wikipedia.org/wiki/Nucleoli
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| nucleophile |
In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. A nucleophile participates in a chemical reaction by donating electrons to a species known as an electrophile in order to form a chemical bond. Because nucleophiles donate electrons, they are by definition Lewis bases (see acid-base reaction theories). ...
출처: en.wikipedia.org/wiki/Nucleophile
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| nuclear chemistry |
Nuclear chemistry is a subfield of chemistry dealing with radioactivity, nuclear processes and nuclear properties. It may be divided into the following categories: * Radiochemistry deals with the use of radioactivity to study ordinary chemical reactions* The application of techniques from chemistry to study nuclear reactions such as fission and fusion — see also nuclear physics. ...
출처: en.wikipedia.org/wiki/Nuclear_chemistry
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| nuclear energy |
Nuclear power currently involves converting the nuclear energy of fissable uranium into thermal energy by fission, from thermal to kinetic energy by means of a steam turbine and finally to electron energy by a generator. Nuclear reactors currently use nuclear power to provide about 17% of the world's electricity and 7% of global energy. ...
출처: en.wikipedia.org/wiki/Nuclear_Energy
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| nuclear energy |
Nuclear energy is energy released from the nucleus of an atom by the conversion of its mass to energy consistent with Albert Einstien's formula E=mc?in which E = Energy, m = Mass and c = the Constant Speed of Light. Nuclear energy is released by one of three nuclear reactions:*Fission, the breaking of the binding forces of an atom's nucleus.*Fusion, the fusing together of atomic particles.*Decay, which is the natural and much slower form of Fission. ...
출처: en.wikipedia.org/wiki/Nuclear_energy
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