| Parallel Electron Energy Loss Spectroscopy | <technique> Electron energy loss spectroscopy analyses the inelastically scattered electrons present in the beam after it has been transmitted through the sample. An electron energy loss spectrum typically consists of a monatomic decreasing background on which are superimposed a number of peaks. Each peak is characteristic of the scattering process that has occurred in the sample. The peaks can be used to obtain information about the chemical composition and electronic structure of the sample. Electron energy loss spectra are acquired typically in a magnetic sector spectrometer located under the camera chamber of the transmission electron microscope. Spatial resolution is typically limited by the minimum probe diameter of the microscope. Electron energy loss spectroscopy tends to be complimentary to EDS in that it can be used to analyse very thin samples of low Z materials. Acronym: PEELS (05 Aug 1998) |
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| Energy Dispersive Spectroscopy | <technique> A microanalytical technique that is based on the characteristic X-ray peaks that are generated when the high energy beam of the electron microscope interacts with the specimen. Each element yields a characteristic spectral fingerprint that may be used to identify the presence of that element within the sample. The relative intensities of the spectral peaks may be used to determine the relative concentrations of each element in the specimen. The X-ray signal is detected by a solid-state silicon-lithium detector and the construction and efficiency of this detector sets a lower limit on the atomic number that may be detected. Generally elements heavier than carbon (Z=5) are detectable. Acronym: EDS (05 Aug 1998) |
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| electron spin resonance spectroscopy | <radiology> A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. electron nuclear double resonance (endor) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications. (12 Dec 1998) |
| absorption spectroscopy | <investigation> This is the use of a spectrophotometer to measure the ability of particles (solutes) in a solution to absorb light through a range of specific wavelengths. Every compound absorbs light differently, so absorption spectra can be used to identify compounds, measure concentrations, and determine reaction rates. (15 Jan 1998) |
| magnetic resonance spectroscopy | Detection and measurement of the resonant spectra of molecular species in a tissue or sample. (05 Mar 2000) |
| clinical spectroscopy | Spectroscopic examination of specimens of living tissue, including fluids removed therefrom. Synonym: clinical spectroscopy. Origin: bio-+ L. Spectrum, image, + G. Skopeo, to examine (05 Mar 2000) |
| spectroscopy | <procedure> Spectroscopy is the science of measuring the emission and absorption of different wavelengths (spectra) of visible and non-visible light, this can be done via a spectroscope, which consists of a slit, prism, collimator lens, object lens, and a grating. (09 Oct 1997) |
| spectroscopy, fourier transform infrared | A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained. (12 Dec 1998) |
| spectroscopy, mossbauer | A spectroscopic technique which uses the mossbauer effect (inelastic scattering of gamma radiation resulting from interaction with heavy nuclei) to monitor the small variations in the interaction between an atomic nucleus and its environment. Such variations may be induced by changes in temperature, pressure, chemical state, molecular conformation, molecular interaction, or physical site. It is particularly useful for studies of structure-activity relationship in metalloproteins, mobility of heavy metals, and the state of whole tissue and cell membranes. (12 Dec 1998) |
| spectroscopy, near-infrared | A noninvasive technique that uses the differential absorption properties of haemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional haemodynamics and blood flow. Near-infrared light (nir) can propagate through tissues and at particular wavelengths is differentially absorbed by oxgenated vs. Deoxygenated forms of haemoglobin and myoglobin. Illumination of intact tissue with nir allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition. (12 Dec 1998) |
| infrared spectroscopy | The study of the specific absorption in the infrared region of the electromagnetic spectrum; used in the study of the chemical bonds within molecules. (05 Mar 2000) |
| radiographic parallel line shadows | The images of bronchial walls, usually thickened; colloq., British. Synonym: radiographic parallel line shadows. (05 Mar 2000) |
| parallel | 1. Pertaining to straight lines or planes that do not intersect. 2. <physics> Pertaining to electric circuit components connected in parallel so that the current flow divides, each branch passing through one component and rejoins, applied by extension to any similar parallel circuit, for example the systemic circulation to the various organs. (18 Nov 1997) |
| parallel attachment | A frictional or mechanically retained unit used in fixed or removable prosthodontics, consisting of closely fitting male and female parts, an attachment that may be rigid in function or may incorporate a movable stress control unit to reduce the torque on the abutment. Synonym: frictional attachment, internal attachment, key attachment, keyway attachment, parallel attachment, slotted attachment. (05 Mar 2000) |
| parallel rays | Ray's parallel to the axis of an optical system. (05 Mar 2000) |
| parallel track | <pharmacology> A system for distributing certain experimental drugs to people who are unable to participate in ongoing clinical trials. (09 Oct 1997) |