Cell oscillator

Bos, F. (1981) Optimization of spectral coverage in an eight-cell oscillator-amplifier dye laser pumped at 308nm. Appl. Opt. 20, 3553. 

Figure 30-15 (A) Diagram of the two-dimensional tree formed by dendrites of a single Purkinje cell of the cerebellum. From Llinas.404 (B) Schematic diagram showing input and output pathways for Purkinje cells. (C) Recordings of output from four different neurons of the inferior olive. These action potentials are thought to arise from oscillations that arise within the neurons or within arrays of adjacent neurons coupled by electrical (gap junction) synapses. These oscillations synchronize the generation of action potentials so that some cells oscillate in synchrony while others (e.g., cell 4 above) do not. From McCormick.412...

The cell cycle automaton model permits us to clarify the reason why circadian delivery of 5-FU is least or most toxic when it peaks at 4 a.m. or 4 p.m., respectively. Indeed, the model allows us to determine the position of the peak in S-phase cells relative to that of the peak in 5-FU. As shown in Fig. 10.5, 5-FU is least cytotoxic when the fraction of S-phase cells oscillates in antiphase with 5-FU (when 5-FU peaks at 4 a.m.) and most toxic when both oscillate in phase (when 5-FU peaks at 4 p.m). Intermediate cytotoxicity is observed for other circadian patterns of 5-FU (when the drug peaks at 10 a.m. or 10 p.m.), for which the peak of 5-FU partially overlaps with the peak of S-phase cells. For the continuous infusion of 5-FU, the peak in S-phase cells necessarily occurs in the presence of a constant amount of 5-FU. Hence, the constant delivery pattern is nearly as toxic as the circadian pattern peaking at 4 p.m. 

Fig. 4.6. Two cells which differ in their PLC activity are coupled. Uncoupled the cells oscillate with their own period (27, 18.8 and 11.6 sec for Vpz,c = 0.8, 1 and 1.5 pM/s respectively). The region of synchronous, 1 1 phase-locked oscillations depends on the intercellular permeabilities for Ca " " and IP3 (7c and 7p respectively). Parameters as in Fig. 4.4.

Fig. 5.4 Displacement vectors and their symmetries for the 12 phonons in the naphthalene crystal at the P point, i.e. at (C= 0. In each mode, at the T point all the unit cells oscillate In phase. In the rotational vibrations 4, 9 and 12, the two molecules in the unit cell...

A quite flexible class of models has been described by Ramkrishna et al. (1966, 1967) using a sequence of reactions in which intermediary products inactivate viable cells. Oscillations of growth can be quantified using this model (Knorre, 1976), and a model of this type was used by Fishman and Biryukov (1974) for growth in penicillin fermentation. A similar approach is used in general analyses of growth patterns subject to the influence of intermediates (Knorre, 1980 Petrova et al., 1977). 

When the meniscus oscillations are excited by external pressure oscillations (8Vp,., (t) = 0, Fig. 2) then according to Eqs. (21) and (22), the pressure oscillations in the cell are described by the same Eq. (27) with the additional factor Bef/VA on the right hand side. The pressure in the cell oscillates synchronously with the meniscus oscillation. When the meniscus oscillations... 

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