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991.
Electron paramagnetic resonance (EPR) and absorption spectroscopy have been used to study the low temperature photochemical behavior of the Photosystem II D-1/D-2/ cytochrome b559 reaction center complex. The reaction center displays large triplet state EPR signals which are attenuated after actinic illumination at low temperatures in the presence of sodium dithionite. Concomitant with the triplet attenuation is the buildup of a structured radical signal with an effective g value of 2.0046 and a peak-to-peak width of 11.9 G. The structure in the signal is suggestive of it being comprised in part of the anion radical of pheophytin a. This assignment is corroborated by low temperature optical absorbance measurements carried out after actinic illumination at the low temperatures which show absorption bleachings at 681 nm, 544 nm and 422 nm and an absorbance buildup at 446 nm indicating the formation of reduced pheophytin.Abbreviations EPR
electron paramagnetic resonance 相似文献
992.
993.
Harry S. Prihar Steven R. Wanamaker Stephanie J. Duber Edward J. Bethrman 《Carbohydrate research》1977,56(2):315-324
Fusion or β-l-fucopyranose tetraacetate with phosphoric acid for 1 min at 50° gives a 9:1 anomeric mixture of the α-and β-pyranosyl phosphates. Longer fusion times give the α-anomer exclusively. The l-fucofuranose tetraacetates were synthesized for the first time by acetolysis or methyl-2,3,5-tri-O-acetyl-β-l-fucofuranoside. Fusion or the furanose tetraacetates with phosphoric acid gave a mixture or the fucofuranosyl phosphates in which the β-anomer predominated (β/α = 2.4). Anomeric pairs in the fucofuranose series appear to be distinguishable by the chemical shift of the C-6 methyl protons, as already shown by Sinclair and Sleeter in the pyranose series. 相似文献
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995.
997.
Harry Campbell 《BMJ (Clinical research ed.)》1905,2(2325):208-209
998.
To demonstrate whether nutritional lithium deficiency is associated with behavioral changes, male Sprague-Dawley rats were
placed on a lithium-deficient diet (Li content <.01 ppm). A lithium-deprived group, receiving drinking water containing 31
μM NaCl, were compared to a control group receiving drinking water containing 31 μM LiCl. Growth and general appearance were the same in both groups. However, lithium-deficient animals demonstrated decreased
aggression in social interactions with other rats and also in response to handling. The phase of wheel-running activity was
delayed by 0.8 h and exhibited decreased amplitude (p<.05). Other behaviors, including acquisition and retention of a passive avoidance response, were unaffected by lithium deprivation.
An erratum to this article is available at . 相似文献
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1000.