6 resultados para B-7

em Brock University, Canada


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The x-ray crystal structure of thiamine hydroiodide,C1ZH18N40S12' has been determined. The unit cell parameters are a = 13.84 ± 0.03, o b = 7.44 ± 0.01, c = 20.24 ± 0.02 A, 8 = 120.52 ± 0.07°, space group P2/c, z = 4. A total of 1445 reflections having ,2 > 2o(F2), 26 < 40° were collected on a Picker four-circle diffractometer with MoKa radiation by the 26 scan technique. The structure was solved by the heavy atom method. The iodine and sulphur atoms were refined anisotropically; only the positional parameters were refined for the hydrogen atoms. Successive least squares cycles yielded an unweighted R factor of 0.054. The site of protonation of the pyrimidine ring is the nitrogen opposite the amino group. The overall structure conforms very closely to the structures of other related thiamine compounds. The bonding surrounding the iodine atoms is distorted tetrahedral. The iodine atoms make several contacts with surrounding atoms most of them at or near the van der Waal's distances A thiaminium tetrachlorocobaltate salt was produced whose molecular and crystal structure was j~dged to be isomorphous to thiaminium tetrachlorocadmate.

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Survey map of the Second Welland Canal created by the Welland Canal Company showing the canal as it passes through the Village of Thorold. Identified structures associated with the Canal include Locks 23, 24, and 25, a Guard Gate, Lock House Lot, the Little Deep Cut, and the towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks are also identified and include streets and roads(ex. Pine Street and Front Street), a basin, a mill race, McPherson and Wier's Grist Mill, Brown and Ross Flouring Mill, R. James Store, J. Brown Cement Mill, W. B. Hendershots Store, Keefers Mill, J. Woodward Grist Mill, Brierly McWhirter and Co. Cotton Mill, E. W. Stephenson Tavern, a factory and a saw mill on W. H. Ward's property, a flouring mill, engine house, a store house, several barns, J. Brown's Wharf, and a number of structures belonging to: Jenkinson, Mrs. McCarty, John Clay, M. McDonnah, Mrs. Donahoc, W. B. Hendershott, Mrs. Pawling, and Christy. Properties and property owners of note are: Lots 8, 9, 16, and 17, W. H. Ward, J. Keefer, G. Keefer Jr., G. Keefer Sr., Dr. Rolls, W. Hendershott, Cleveland, Lucy, and R. Leeper.

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Ben N. Peach (1842-1926) was a well-known geologist whose work focused on the geological structure of Scotland, and in particular the Northwest Scottish Highlands and Southern Uplands. He formed a close working relationship with John Horne and the two colloborated on many works, most notably two memoirs of the Geological Survey of Great Britain, The Silurian Rocks of Britain (1899) and The Geological Structure of the North-West Highlands of Scotland (1907).

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The cholesterol chelating agent, methyl-b-cyclodextrin (MbCD), alters synaptic function in many systems. At crayfish neuromuscular junctions, MbCD is reported to reduce excitatory junctional potentials (EJPs) by impairing impulse propagation to synaptic terminals, and to have no postsynaptic effects. We examined the degree to which physiological effects of MbCD correlate with its ability to reduce cholesterol, and used thermal acclimatization as an alternative method to modify cholesterol levels. MbCD impaired impulse propagation and decreased EJP amplitude by 40% (P,0.05) in preparations from crayfish acclimatized to 14uC but not from those acclimatized to 21uC. The reduction in EJP amplitude in the cold-acclimatized group was associated with a 49% reduction in quantal content (P,0.05). MbCD had no effect on input resistance in muscle fibers but decreased sensitivity to the neurotransmitter L-glutamate in both warm- and coldacclimatized groups. This effect was less pronounced and reversible in the warm-acclimatized group (90% reduction in cold, P,0.05; 50% reduction in warm, P,0.05). MbCD reduced cholesterol in isolated nerve and muscle from cold- and warmacclimatized groups by comparable amounts (nerve: 29% cold, 25% warm; muscle: 20% cold, 18% warm; P,0.05). This effect was reversed by cholesterol loading, but only in the warm-acclimatized group. Thus, effects of MbCD on glutamatesensitivity correlated with its ability to reduce cholesterol, but effects on impulse propagation and resulting EJP amplitude did not. Our results indicate that MbCD can affect both presynaptic and postsynaptic properties, and that some effects of MbCD are unrelated to cholesterol chelation.

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Letter to S.D. Woodruff from Mr. Tisdale stating that William B. Hunter will only pay $60 for shooting for this year. He asks if Mr. Woodruff will accept this. There is a reply at the bottom of the letter in which [S.D. Woodruff] replies that he will not accept $60, but $100 will be acceptable, Sept. 7, 1870.