Withdrawal time, definition

The eigenvalues calculated either by the Merrifield or ABO method are nearly identical. As can be seen, this analysis leads to the prediction of a number of low-lying infrared absorption bands for this complex. In a discussion of the structure of the Creutz-Taube ion, I pointed out some time ago (27) that the evidence definitely favors a well-delocalized ground state (6 < 1), and predicted that these infrared bands would, thus, not be observed. In a recent publication, Krausz, et al., report that a search for the bands indeed gave negative results, and withdraw their proposed interpretation of the spectrum (48). 

The beneficial effects were related to these plasma concentrations, as were the time to the first bout of atrial fibrillation, the frequency of bouts of atrial fibrillation, and the time between episodes. However, when atrial fibrillation occurred there was no difference in the ventricular rate in the different groups. Adverse effects necessitated drug withdrawal in four patients one had heart failure and two had gastrointestinal symptoms. These effects were not dose-related, although there were too few occurrences for a definitive conclusion. The authors suggested that this stepwise approach, with increasing doses of propafenone and increasing doses of quinidine could be beneficial in the treatment of paroxysmal atrial fibrillation. 

If little or no previous data on the metabolism of the compound in the target species is available, it is prudent to consider conducting a probe residue depletion study in three animals sacrificed at three widely spaced intervals following the last dose. For example, one animal might be sacrificed at 12 hours (zero withdrawal) and another each at 72 and 120 hours post final dose (the exact times selected will depend on the tissue clearance of the drug under development). The information obtained will allow one to select more accurately sacrifice intervals for the definitive study which encompass proposed safe concentrations of total drug-related residue. Additionally, the probe study residue data will allow for adjustments in the specific activity of the radiolabeled dose to ensure tissue concentrations of total radioactivity at later sacrifice intervals which are sufficient for metabolite profiling and isolation. 

A residence time smaller than 1 minute using the above definition may be satisfactory on chimney trays that are used for withdrawing pumparound liquid in nonfoaming services. Because of the large circulation rate ts pical in such applications, a 1-minute residence time may require an excessively tall chimney tray. Since pumps used in such applications t3q>ically develop low heads, they usually can tolerate some entrained vapor. 

Withdrawal Order - A term reierrlng to the sequence of movement of the HCJR s during a start-up. After a reactor has started up or during the process of starting up, the HCR s are withdrawn in a definite sequence or "withdrawal order." Then as the reactivity increases due to Xe burnout, buildup, and heating of the graphite, the HCR s must be inserted to control the reactivity. This is called the insertion order and is the. reverse order until such time as temperature effects dictate otherwise. 

As acetic acid is produced on hydrolysis, the progress of the reaction is followed by withdrawing definite volumes of the reaction mixture at suitable time intervals and titrating against a standard alkali solution. The increase in the volume of alkali used is a measure of methyl acetate hydrolysed. If V,, and Too... 

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