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11.
The interaction of an organic acid with sodium bicarbonate in water produces an effervescent reaction. The reaction products are carbon dioxide, water, and the sodium salt of the acid. The kinetic rate-determining step for this reaction is the dehydration of carbonic acid. The solid-solid interaction with known amounts of moisture was followed by quantitatively determining carbon dioxide evolution as a function of time. The aqueous solubilities, diffusion coefficients, dissociation constants, and solid-solid interaction rates of six different substituted benzoic acids were determined. Using a model based on diffusion of the organic acid through the aqueous layer coupled with chemical reaction, predicted rates and levels of carbon dioxide production were compared with experimental results. Included in the model were the effects of the reaction products on the solution properties of the reactants. It was found that high concentrations of substituted sodium benzoate were generated very quickly and affected the solubility of the reactants, diffusion coefficient of the acid, and the carbonic acid dehydration rate constant. Moisture content was found to have a profound influence on the interaction rate. Water provides a medium for diffusion of the reacting species as well as the reaction solvent. 相似文献
12.
Wright RE 《The British journal of ophthalmology》1940,24(11):547-559
13.
Steven Z George John D Childs Deydre S Teyhen Samuel S Wu Alison C Wright Jessica L Dugan Michael E Robinson 《BMC musculoskeletal disorders》2007,8(1):92
Background
There are few effective strategies reported for the primary prevention of low back pain (LBP). Core stabilization exercises targeting the deep abdominal and trunk musculature and psychosocial education programs addressing patient beliefs and coping styles represent the current best evidence for secondary prevention of low back pain. However, these programs have not been widely tested to determine if they are effective at preventing the primary onset and/or severity of LBP. The purpose of this cluster randomized clinical trial is to determine if a combined core stabilization exercise and education program is effective in preventing the onset and/or severity of LBP. The effect of the combined program will be compared to three other standard programs. 相似文献14.
15.
L. C. Scott G. K. Wright G. S. Rai A. N. Exton-Smith J. M. Gardiner 《International journal of geriatric psychiatry》1991,6(8):583-588
Memory performance of elderly patients in the early stages of Alzheimer's disease (DAT) was compared with that of elderly control subjects. In explicit tests of recognition memory, which involve conscious recollection, the DAT patients were grossly impaired. In implicit tests of anagram solution and wordstem completion, which do not require conscious recollection, the DAT patients were not impaired. These findings further support the idea that a separate memory system, episodic memory, underlies conscious recollection, that it is this system which is most commonly damaged in amnesia, and that memory systems not involving conscious recollection may be spared in the early stages of Alzheimer's disease. 相似文献
16.
We report a case of multiple endocrine neoplasia type I and hypernephroma. Parathyroid hyperplasia, adrenocortical hyperplasia, a nodular goiter, multiple lipomas, a chromophobe adenoma of the pituitary and hypernephroma had all been diagnosed previously. All but the last are features consistent with the diagnosis of multiple endocrine neoplasia type I (Wermer's syndrome). The association of multiple endocrine neoplasia type I and hypernephroma may represent a new manifestation of this pleiotropic syndrome. 相似文献
17.
New indole alkaloid glycosides from Nauclea orientalis 总被引:4,自引:0,他引:4
Two new indole alkaloid glycosides, 10-hydroxystrictosamide and 6'-O-acetylstrictosamide, as well as the known alkaloids strictosamide and vincosamide were isolated from the leaves of Nauclea orientalis L. The structures of the isolated compounds were determined using spectroscopic methods, mainly 1D- and 2D-NMR spectroscopy. 相似文献
18.
19.
A F Wright 《The British journal of general practice》1998,48(432):1375-1376
20.
8-OH-DPAT and buspirone analogs inhibit the ketanserin-sensitive quipazine-induced head shake response in rats 总被引:2,自引:0,他引:2
F D Yocca R N Wright R R Margraf A S Eison 《Pharmacology, biochemistry, and behavior》1990,35(1):251-254
Behavioral syndromes mediated by serotonergic mechanisms may reflect interactions between distinct effects initiated by specific 5-HT receptors, such as the 5-HT1A and the 5-HT2 receptor. This hypothesis was tested by examining the effect of various 5-HT1A agonists on the 5-HT2 receptor-mediated quipazine-induced head shake response in rats. Subcutaneous administration of 8-OH-DPAT, buspirone, gepirone, and ipsapirone produced a dose-dependent inhibition of the ketanserin-sensitive quipazine-induced head shake response. These effects were produced by doses of agonists which did not induce reciprocal forepaw treading. Furthermore, pretreatment with a partial 5-HT1A agonist (+/-)pindolol blocked the inhibitory effects of 8-OH-DPAT to the level of inhibition produced by (+/-)pindolol itself. These results suggest that stimulation of central 5-HT1A receptors can modulate the expression of a central 5-HT2 receptor-mediated behavior. 相似文献