form an amide. This reaction is widely used‚ especially in the synthesis of peptides. On the simple addition of an amine to a carboxylic acid‚ a salt of the organic acid and base is obtained. To overcome this‚ the carboxylic acid first needs to be "activated". This is usually done by converting the acid into a more reactive derivative (i.e. anhydride‚ acid halide) or by using a coupling agent. In some cases‚ high temperatures (>200 °C) can overcome salt formation by driving off water‚ without the need
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Describe the physiological approach to the study of the mind. Explain how Donders experiment can be repeated in a modern laboratory using the physiological approach to the study of the mind Donder’s work attempts to describe the processes going on in the mind‚ by analyzing cognitive activity into separate stages. Until Donder’s work‚ many scientists had assumed that the mental operations involved in responding to a stimulus occurred instantaneously. Donder was particularly interested in "timing
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hand warmers‚ mainly the iron powder and activated charcoal‚ and oxygen in the atmosphere‚ react with each other chemically to create warmth. Inside the pouch‚ there is iron powder. When it comes in contact with oxygen‚ the iron rusts and releases heat. The outside bag is a microporous pouch‚ which has tiny holes that are big enough to allow air inside‚ providing the oxygen for the reaction between iron and oxygen. Inside the hand warmer‚ there is also activated charcoal‚ which is charcoal that has been
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the charectersitic spectrum. Activated Alumina: Activated Alumina is a granulated form of aluminum oxide. In this process‚ water containing the contaminant is passed through a cartridge or canister of activated alumina which adsorbs the contaminant. The cartridge of activated alumina must be replaced periodically. Activated alumina devices can accumulate bacteria‚ so treated water may have higher bacteria counts than raw water. The advantages of Activated Alumina filters include: 1.
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Chapter 14: Signal Transduction Mechanisms: Messengers and Receptors Signal Transduction Mechanisms: II. Messengers and Receptors In the second major means of intercellular communication the signal is transmitted by regulatory chemical messengers Receptors are located on receiving cells that can be quite distant from the secreting cell Chemical Signals and Cellular Receptors Cells produce signals‚ in some cases by displaying molecules on their surfaces or by releasing a chemical signal Multicellular
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others. Mysticism aside‚ the study of blood clotting and the development of laboratory tests for blood clotting abnormalities are historically inseparable. The workhorse tests of the modern coagulation laboratory‚ the prothrombin time (PT) and the activated partial thromboplastin time (aPTT)‚ are the basis for the published extrinsic and intrinsic coagulation pathways‚ even though it is now known that these pathways do not accurately reflect the function of blood clotting in a living organism. In this
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record cycles (typical) - 100-year message retention (typical) • Single message of 20 to 30 seconds‚ with external resistor selection • User-friendly‚ easy-to-use operation - Programming & development systems not required - Level-activated recording & edge-activated playback switches • Low power consumption - Operating current: 25 mA (typical‚ no load) - Standby current: 1uA (typical‚ no load) • Automatic power-down feature for longer battery life • Chip enable pin for simple message expansion
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five-minute sessions‚ which involved active or passive music stimulation or no music stimulation. The patients had either pressure devices on the table which could be activated with a simple push of their hand‚ mini shock absorber devices on the back of their hand which activated when clapping‚ or vibration devices on that that could be activated by tapping on the table. In the response-related
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cusps of deep veins. Immobility delays emptying of muscular veins and retards clearance of activated clotting factors. With stasis‚ endothelial cells lining the avascular valve cusps are activated by hypoxemia‚ a process exacerbated by inflammatory cytokines generated postoperatively or in medical illness. Leukocytes tethered to activated endothelial cells express tissue factor‚ whereas platelets become activated and aggregate. Congenital or acquired disorders associated with hypercoagulability promote
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StudyMode - Premium and Free Essays‚ Term Papers & Book Notes Become A StudyMode.com Contributor For our free membership‚ please upload one paper to the site. Please fill out the form below to join the site. Your account will be activated immediately. 1. Personal Information Birthday: 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 January February March April May June July August September October November December 1900
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