| spectrometry, mass, matrix-assisted laser desorption-ionization | A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis. (12 Dec 1998) |
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| spectrometry, mass, secondary ion | A mass-spectrometric technique that is used for microscopic chemical analysis. A beam of primary ions with an energy of 5-20 kiloelectronvolts (kev) bombards a small spot on the surface of the sample under ultra-high vacuum conditions. Positive and negative secondary ions sputtered from the surface are analyzed in a mass spectrometer in regards to their mass-to-charge ratio. (12 Dec 1998) |
| spectrum analysis, mass | Analysis of the mass of an object through means of determining the wave length(s) at which electromagnetic energy is absorbed by that object. (12 Dec 1998) |
| injection mass | Coloured solutions or suspensions injected into the vascular system to render vessels and their walls prominent; useful for gross preparations and for study under low magnification after clearing; most fluids contain warm gelatin and the colouring materials are carmine, Berlin blue, or carbon. (05 Mar 2000) |
| intermediate mass | The variable connection between the two thalamic masses across the third ventricle; absent in about 20% of human brains. Synonym: adhesio interthalamica, commissura cinerea, commissura grisea, intermediate mass, massa intermedia. (05 Mar 2000) |
| intradural-extramedullary mass | <radiology> Meniscus sign, neurofibroma / schwannoma, meningioma, drop metastasis, lipoma, dermoid, angioma, ependymoma of filum terminale (really intramedullary) (12 Dec 1998) |
| intramedullary mass | <radiology> Ependymoma, astrocytoma, syrinx, post-radiation myelopathy, haematoma (posttraumatic or AVM) (12 Dec 1998) |
| the large mass of the telencephalon | On either side of the midline, consisting of the cerebral cortex and its associated fibre systems, together with the deeper-lying subcortical telencephalic nuclei (i.e., basal ganglia [nuclei]). (05 Mar 2000) |
| tubular excretory mass | The mass of functioning excretory tubules of the kidney determined from the excretion of iodopyracet, or other compounds processed in the kidney primarily by tubular secretion, when large doses are used. (05 Mar 2000) |
| extradural mass | <radiology> Disc, haematoma (traumatic fracture), metastasis (epidural, bony), abscess, neurofibroma, lipoma, arachnoid cyst (12 Dec 1998) |
| unit of mass | Metric system: gram, SI: kilogram, english system: pound. (05 Mar 2000) |
| filar mass | A filamentous plasmatic material, beaded with granules, demonstrable by means of vital staining in the immature red blood cells. Synonym: alpha substance, filar mass, filar substance, substantia reticularis, substantia reticulofilamentosa. Synonym: reticular formation. (05 Mar 2000) |
| lateral mass of atlas | The thick lateral part of the atlas on each side that articulates above with the occipital condyle and below with the axis. Synonym: massa lateralis atlantis. (05 Mar 2000) |
| lateral mass of ethmoid bone | A mass of air cells with thin bony walls forming part of the lateral wall of the nasal cavity; the cells are arranged in three groups, anterior, middle, and posterior, and are closed laterally by the orbital plate which forms part of the wall of the orbit. Synonym: labyrinthus ethmoidalis, ectethmoid, ectoethmoid, lateral mass of ethmoid bone. (05 Mar 2000) |
| fourth ventricle mass | <radiology> IN ADULTS: choroid plexus papilloma, haemangioblastoma, vermian metastasis, arteriovenous malformation (AVM), inflammatory mass/cyst IN KIDS: medulloblastoma, uniform enhancement, homogeneous, ependymoma, patchy enhancement, heterogeneous, calcified (12 Dec 1998) |