Historical elements

The first intracellular effect mediated by dopamine receptors that has been reported was the stimulation of the production of cyclic AMP (cAMP) in target cells. This effect was originally described in the superior cervical ganglia and the cow retina (Kebabian and Greengard, 1971 Brown and Makman, 1972) and soon afterward, in the CNS, in rat striatum (Kebabian et al., 1972). Antipsychotic drugs were found to block this response (Clement-Cormier et al., 1974 Miller et al., 1974) and this was the first direct evidence supporting the hypothesis proposed by A. Carlsson in the 1960s that the therapeutic actions of neuroleptics result from their ability to block dopamine receptors. 

It was later found that some effects of dopamine did not involve stimulation of adenylyl cyclase. Particularly, in the pituitary gland, dopamine was found to inhibit prolactin release without stimulating adenylyl cyclase activity and even by inhibiting it (Spano et al., 1978 De Camilli et al., 1979). Moreover, the antipsychotic drug sulpiride blocked the dopamine-induced release of prolactin in the pituitary gland but was unable to antagonize the dopamine response on adenylyl cyclase activity in the striatum (Trabucchi et al., 1975). These observations led to the hypothesis that the dopamine receptors exist as two 

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Other authors have additionally argued that, by the use of historic elements ... 

Accepting these arguments, it should be a matter of course for teachers to use historic elements in teaching science in general and chemistry in particular. However,... 

Historically, elemental formulas designed for renal failure were enriched with essential amino acids (EAAs) and contained lesser amounts of nonessential amino acids (NEAAs) than standard formulas. Theoretically, EAAs could combine with urea nitrogen in the synthesis of NEAAs, thus leading to a decrease in blood urea nitrogen (BUN). The only situation in which such formulas may be appropriate is in patients with... 

To verify this hypothesis, low volume samplers have been operated in parallel with the air pollution control district s Km samplers. The samples collected were analyzed optically for elemental carbon and by the Gamma Ray Analysis of Light Elements (GRALE) technique for total carbon. These data were used to assess the concentration of elemental and total carbon aerosols present during the winter months in Los Angeles. It was established that the Km samplers can be calibrated to read elemental carbon concentrations. This calibration can be used to reconstruct historical elemental carbon levels at seven sites in Los Angeles. 

Clean historic elements first. Use nonabrasive household cleansers. 

If you treat nonhistoric features, do not harm historic elements. 

This edition today already possesses a historical element for me, as a revision had originally been projected for the fifth year after the initial publication. However, with a team of authors as large as ours, the comparison with a ship - fully loaded, difficult to manoeuvre - may not be inadequate and 1 am, therefore grateful today that there have been only minor deviations from the original schedule. 

Cervus elaphus, where the signal is energetically very expensive to produce (Clutton-Brock and Albon, 1979). Scent marking in territories may have evolved as a form of status advertisement because it takes some time to comprehensively mark a territory (one week for a newly arrived Thomson s gazelle male Walther, 1978a) and, since a male that has done this must have successfully defended the territory, it must actually be the owner. The historical element in scent marking thus makes it uniquely cheat-proof. 

Molecular mechanics methods have only been used to a limited extent for these classes of compounds. However, molecular mechanics methods do fairly well in describing the geometries and relative energies of compounds with these elements. It is perhaps only for historical and economic reasons that molecular mechanics has not been used more for modeling these elements. Subsequently, there are not as many force fields available. 

There is potential confusion in the use of the word array in mass spectrometry. Historically, array has been used to describe an assemblage of small single-point ion detectors (elements), each of which acts as a separate ion current generator. Thus, arrival of ions in one of the array elements generates an ion current specifically from that element. An ion of any given m/z value is collected by one of the elements of the array. An ion of different m/z value is collected by another element. Ions of different m/z value are dispersed in space over the face of the array, and the ions are detected by m/z value at different elements (Figure 30.4). 

Different combinations of stable xenon isotopes have been sealed into each of the fuel elements in fission reactors as tags so that should one of the elements later develop a leak, it could be identified by analyzing the xenon isotope pattern in the reactor s cover gas (4). Historically, the sensitive helium mass spectrometer devices for leak detection were developed as a cmcial part of building the gas-diffusion plant for uranium isotope separation at Oak Ridge, Tennessee (129), and heHum leak detection equipment is stiU an essential tool ia auclear technology (see Diffusion separation methods). 

In the days of alchemy and the phlogiston theory, no system of nomenclature that would be considered logical ia the 1990s was possible. Names were not based on composition, but on historical association, eg, Glauber s salt for sodium sulfate decahydrate and Epsom salt for magnesium sulfate physical characteristics, eg, spirit of wiae for ethanol, oil of vitriol for sulfuric acid, butter of antimony for antimony trichloride, Hver of sulfur for potassium sulfide, and cream of tartar for potassium hydrogen tartrate or physiological behavior, eg, caustic soda for sodium hydroxide. Some of these common or trivial names persist, especially ia the nonchemical Hterature. Such names were a necessity at the time they were iatroduced because the concept of molecular stmcture had not been developed, and even elemental composition was incomplete or iadeterminate for many substances. 

Potassium [7440-09-7] K, is the third, element ia the aLkaU metal series. The name designation for the element is derived from potash, a potassium mineral the symbol from the German name kalium, which comes from the Arabic qili, a plant. The ashes of these plants al qili) were the historical source of potash for preparing fertilisers (qv) or gun powder. Potassium ions, essential to plants and animals, play a key role in carbohydrate metaboHsm in plants. In animals, potassium ions promote glycolysis, Hpolysis, tissue respiration, and the synthesis of proteins (qv) and acetylcholine. Potassium ions are also beheved to function in regulating blood pressure. 

Historically, EELS is one of the oldest spectroscopic techniques based ancillary to the transmission electron microscope. In the early 1940s the principle of atomic level excitation for light element detection capability was demonstrated by using EELS to measure C, N, and O. Unfortunately, at that time the instruments were limited by detection capabilities (film) and extremely poor vacuum levels, which caused severe contamination of the specimens. Twenty-five years later the experimental technique was revived with the advent of modern instrumentation. The basis for quantification and its development as an analytical tool followed in the mid 1970s. Recent reviews can be found in the works by Joy, Maher and Silcox " Colliex and the excellent books by Raether and Egerton. ... 

If the critical impurities are known, then only a selected list of elements need to be examined, with some improvement in the cost effectiveness of the analysis. However, the list of elements to be included in the qualification analysis is often historical and related to the limitations of the analytical methods previously used for qualification rather than for technological reasons related to the end use of the metal. As a result, problems in application can arise for no obvious reason. The time and cost of extending the impurity list for GDMS analysis to include essentially all elements is minimal, considering the additional information gained. 

Local Thermodynamic Equilibrium (LTE). This LTE model is of historical importance only. The idea was that under ion bombardment a near-surface plasma is generated, in which the sputtered atoms are ionized [3.48]. The plasma should be under local equilibrium, so that the Saha-Eggert equation for determination of the ionization probability can be used. The important condition was the plasma temperature, and this could be determined from a knowledge of the concentration of one of the elements present. The theoretical background of the model is not applicable. The reason why it gives semi-quantitative results is that the exponential term of the Saha-Eggert equation also fits quantum-mechanical expressions. 

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