Cycling variables

A systematic study of the cycling variables, cycle period (r), flush duration (D) or cycle split (s), and the liquid loading (m 1) for the poorer performing BPL activated carbon is reported by Lee et al (1995). All their measurements were undertaken at 80°C. Contrary to the influence of period seen in Fig. 27, Lee et al. observed that S02 removal and conversion to acid increase as r augments while holding s constant. Results of this study are summarized in Fig. 29. The middle figure suggests there is an optimum... 

InAs, formed with 200 cycles. There are no indications of As in the XRD. From Figure 25, a plot of the (ahv)2 vs. energy, the bandgap was estimated to be 0.36 eV, in agreement with literature values. Bandgaps for the InAs deposits appear to be sensitive functions of a number of cycle variables. Several samples resulted in band gaps of closer to 0.44 eV. These blue shifts appear to result from smaller crystallites, nanoclusters, when the deposition conditions were not optimal. 

What are the consequences of water cycle variability on various spatiotemporal scales for human activity and ecosystems, how can this variability influence the Earth s system, thus affecting the transport of deposits and biogenes and affecting biogeochemical cycles ... 

To investigate the effect of the peak time of circadian delivery of 5-FU, we compare in Fig. 10.4a four circadian schedules with peak delivery at 4 a.m., 10 a.m., 4 p.m., and 10 p.m., for a cell cycle variability of 15%. The data on cumulated cell kill by 5-FU indicate a sharp difference between the circadian schedule with a peak at 4 a.m., which is the least toxic, and the other schedules. This difference is even more striking when cells are better synchronized, for smaller values of variability V (data not shown). The most toxic circadian schedules are those with a peak delivery at 4 p.m. or 10 a.m. We compare in Fig. 10.4b the least and most toxic circadian patterns of 5-FU delivery with the continuous infusion of 5-FU. Continuous delivery of 5-FU appears to be slightly more toxic than the circadian pattern with a peak at 4 p.m. 

To clarify the reason why different circadian schedules of 5-FU delivery have distinct cytotoxic effects, we used the cell cycle automaton model to determine the time evolution of the fraction of cells in S phase in response to different patterns of circadian drug administration, for a cell cycle variability of 15%. The results, shown in Fig. 10.5, correspond to the case considered in Fig. 10.4, namely, entrainment of a 22-h cell cycle by the circadian clock. The data for Fig. 10.5a clearly indicate why the circadian schedule with a peak at 4 a.m. is the least toxic. The reason is that the fraction of cells in S phase is then precisely in antiphase with the circadian profile of 5-FU. Since 5-FU only affects cells in the S phase, the circadian delivery of the anticancer drug in this case kills but a negligible amount of cells. 

V 15% in the number of cells killed by the drug. This jump is not observed in the absence of entrainment (data not shown). Entrainment by the circadian clock further enhances the synchronization of cells and protects them from the drug, as long as V remains relatively small, i.e. V 10%. Therefore, circadian entrainment magnifies the consequences of cell cycle variability, as it introduces a threshold in the effect of this parameter. 

Numerical simulations therefore indicate that the least damage to the cells occurs when the peak of 5-FU circadian delivery is at 4 a.m., and when cells are well synchronized, i.e., when cell cycle variability V is lowest. In contrast, when the peak of 5-FU circadian delivery is at 4 p.m., cytotoxicity is enhanced when cells are well synchronized. The cytotoxic effect of the drug, therefore, can be enhanced or diminished by increased cell cycle synchronization, depending on the relative phases of the circadian schedule of drug delivery and the cell cycle entrained by the circadian clock. Continuous infusion of 5-FU is nearly as toxic as the most cytotoxic circadian pattern of anticancer drug delivery. 

Jacket temperature was controlled by connecting the thermoregulator and the heater to an American Instrument Co. relay model No. 4-5300. Power to the heater was supplied by a 60-cycle variable transformer normally operated at about 10 volts. Jacket temperature was recorded by feeding the thermocouple output through a Leeds and Northrup d.c. amplifier (No. 9835-B) to a Speedomax H Azar strip chart recorder. 

Number of samples for one testing cycle Variability, except testing time 1-6 Adaptable pressure (higher for woven than for knitted fabrics) 3-18 Addition of cotton (inters 1-4... 

Shindell, D., D. Rind, N. Balachandran, J. Lean, and P. Lonergan, Solar cycle variability, ozone, and climate. Science 284, 305, 1999. 

Timed collections Urine spot (random), short (<4h), and long/ovemight (12-16h) timed collections, relationship to light cycle Variability in biomarker excretion... 

Polyesters Moderate to high shrinkage, cure cycle variable over wide range, very low viscosity possible, limited compatibihty, low cost, long pot life, easily modified, hmited shelf life, strong odor with styrene Pair adhesion, good electrical properties, water-white, range of flexibilities... 

Steam Cycle/Variable Cogeneration HTGR Plant Description... 

Steam Cycle/Variable Cogeneration HTGR Plant Description (Conceptual Design, Circa 1985)... 

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