The so-called synthesis problem for nets which consists in deciding whether a given automaton is isomorphic to the case graph of a net and then constructing the net has been solved for various type of nets ranging from elementary nets to Petri nets. Though P/T nets admits polynomial time synthesis algorithms, the synthesis problem for elementary nets is known to be NP-complete. Applying the pri...

Cells are complex machines capable of processing information by means of an entangled network of molecular interactions. A crucial component of these decision-making systems is the presence of memory and this is also a specially relevant target of engineered synthetic systems. A classic example of memory devices is a 1-bit memory element known as the flip-flop. Such system can be in principle d...

In order to study the basic physical phenomena underlying complex lipid transbilayer movement in biological membranes, we have measured the transmembrane diffusion of spin-labelled analogues of sphingolipids in phosphatidylcholine (PC) large unilamellar vesicles in the absence or presence of cholesterol, going from a fluid ( liquid disordered) l(d), phase to a more viscous, liquid ordered (l(o)...

We present a biologically-based mathematical model that accounts for several features of the human sleep/wake cycle. These features include the timing of sleep and wakefulness under normal and sleep-deprived conditions, ultradian rhythms, more frequent switching between sleep and wakefulness due to the loss of orexin and the circadian dependence of several sleep measures. The model demonstrates...

Regulatory actions of calmodulin on the contractile apparatus and cytoskeleton of smooth muscle and nonmuscle tissue are mediated by a number of specific calmodulin-binding proteins that bind to F-actin in a flip-flop manner--i.e., they bind to calmodulin or F-actin depending on the presence or absence, respectively, of Ca2+. A survey for such proteins in brain, adrenal gland, and pituitary gla...

Abstract: Power consumption is considered as one of the important challenge in modern VLSI design along with area and speed consideration. Flip flop plays very important role in digital systems. In this paper comparative study of four different flip flops which includes pulse triggered as well as conditional technique flip flop such as IP-DCO, MHLFF, CPSFF, and CPFF topologies in sub threshold ...

We investigated the transbilayer movement or flip-flop of phospholipids in vesicles derived from the cytoplasmic membrane of Bacillus megaterium. Since common assay techniques were found to be inapplicable to the Bacillus system, we exploited and elaborated a newly described method in which fluorescent phospholipids (1-myristoyl-2-C6-NBD phospholipids) are used as tracers to monitor flip-flop. ...

Initial models of AMPA receptor assembly postulated the unrestricted stochastic association of individual subunits. The low Ca(2+) permeability and nonrectified current-voltage relationship of most native AMPA receptors were ascribed to dominant effects of the glutamate receptor 2 (GluR2) subunit. A recent model, however, proposes instead the preferred assembly of GluR1 and GluR2 subunits into ...

all practical digital circuits are usually a mixture of combinational and sequential logic. flip–flops are essential to sequential logic therefore fuzzy flip–flops are considered to be among the most essential topics of fuzzy digital circuit. the concept of fuzzy digital circuit is among the most interesting applications of fuzzy sets and logic due to the fact that if there has to be an ultimat...

The relative stability of cholesterol in cellular membranes and the thermodynamics of fluctuations from equilibrium have important consequences for sterol trafficking and lateral domain formation. We used molecular dynamics computer simulations to investigate the partitioning of cholesterol in a systematic set of lipid bilayers. In addition to atomistic simulations, we undertook a large set of ...