2 resultados para successive-approximation-register (SAR) analog-to-digital converters (ADC)

em Brock University, Canada


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The Weekly Register, also known as Niles Weekly Register was a weekly periodical edited by Hezekiah Niles (1777-1839), and published in Baltimore Maryland. Volumes of Interest were published between 1811 (Vol. 1, No. 1, September 7, 1811) to 1814 (Vol. 5, No. 26, February 26, 1814). These volumes focus primarily on 19th century Politics and Government in the United States of America. Niles edited and published the Weekly Register until 1836, making it one of the most widely-circulated magazines in the United States. The popularity also made Niles into one of the most influential journalists of his day. Devoted primarily to politics, Niles' Weekly Register is considered an important source for the history of the period. The Register also recorded current economics, technology, science, medicine, geography, archaeology, the weather, and stories of human interest. PLEASE CLICK ON THE WEEKLY PERIODICALS ON THE RIGHT OF THE SCREEN (PDF FILES)TO DOWNLOAD FILES. Pages are divided as follows: 1811 September 7th pages 1-16 14th pages 17-32 21st pages 33-48 28th pages 49-72 1811 October 5th pages 73-88 12th pages 89-104 19th pages 105-120 26th pages 121-136 1811 November 2nd pages 137-152 9th pages 153-184 15th pages 185-208 23rd pages 209-224 30th pages 225-240 1811 December 7th pages 241-256 14th pages 257-280 21st pages 281-296 28th pages 299-320 1812 January 4th pages 321-336 11th pages 337-360 18th pages 361-376 25th pages 377-392 1812 February 1st pages 393-408 8th pages 409-432 15th pages 433-448 22nd pages 449-464 29th pages 465-480 PLEASE CLICK ON THE WEEKLY PERIODICALS ON THE RIGHT OF THE SCREEN (PDF FILES)TO DOWNLOAD FILES. Call Number: SPCL PER JK 1 N52

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It has previously been recognized that the major biochemical toxicity induced by sulphide is due to an inhibition of cytochrome ~ oxidase. Inhibition of this enzyme occurs at 30°C and pH 7.4 with a Ki of approximately 0.2 ~M, and a kon of 104 M-1 s-l, under catalytic conditions. However, the equimo1ar mixture of sulphide and the enzyme shows identical catalytic behaviour to that of the native enzyme. This cannot readily be attributed to rapid dissociation of sulphide, as both spectroscopic and plot analysis indicate the koff value is low. The addition of stoichiometric sulphide to the resting oxidized enzyme gives rise to the appearance of a low-spin ferric-type spectrum not identical with that seen on the addition of excess sulphide to the enzyme aerobically. Sulphide added to the enzyme anaerobically gives rise to another low-spin, probably largely ferric, form which upon admission of oxygen is then converted into a 607 nm species closely resembling Compound C. The 607 nm form is probably the precursor of oxyferricytochrome aa3. The addition of successive a1iquots of Na2S solution to the enzyme induces initial uptake of approximately 3 moles of oxygen per mole of the enzyme. Thus, it is concluded that: 1. the initial product of sulphide-cytochrome c oxidase interaction is not an inhibited form of the enzyme, but the low-spin (oxyferri) ~3+~+ species; 2. a subsequent step in which sulphide reduces cytochrome ~ occurs; 3. the final inhibitory step, in which a further molecule of sulphide binds to the cytochrome ~ iron centre in the cytochrome ~2+~+ species, gives the cytochrome a2+~+-H2S form which is a half-reduced fully inhibited species;4. a 607 run form of the enzyme is produced which may be converted into a catalytically active low-spin (oxyferri) state; and therefore 5. liganded sulphide may be able to reduce the cytochrome 33 -Cu centre without securing the prior reduction of the cytochrome a_ haem group or the Cud centre associated with it.