Flip-flop functions

The 4-bit shift register is a simple circuit that suitably demonstrates the aspects of sequential logic design discussed above. Like the multiplexer example in Chapter 4, a number of different design methods are illustrated for the same circuit. Also, other new constructs are introduced as more complex flip flop functions are developed. Again, all the VHDL descrip-... 

There is nothing in Equations 1-8 which is an all-or-none situation. There are no positive feedback loops which might cause some kind of flip-flop of states of operation of the system. There are some possibilities for saturation phenomena but all relationships are graded. Overall, transient or steady-state, the changes of concentration of P-myosin are continuous, monotonic functions of the intracellular Ca ion concentration. On this basis it is more appropriate to say that smooth muscle contraction is modulated rather than triggered by Ca ion. 

Genetic regulation via splice variants and RNA editing further increases receptor heterogeneity the flip/flop versions and the Q/R site. Splice variants that impart functional differences and/or different cellular expression patterns have been found for most of the glutamate receptor subunits. The first splice variants to be described were the so-called flip and flop versions of the AMPA... 

Platelet participation in normal hemostasis. The hemostatic plug is the specific response to external vessel lesion and depends on the extent of vessel wall damage, the specific interaction between endothelial cells and activated platelets, release of the contents of platelets intracellular granules in response to activation, the conjoint activity of activated factor Vll and platelet agonists, and the open conditions of blood flow. After activation, platelets also produce the external ization of membrane phosphatidylserine through the flip-flop mechanism that will support the function of the prothrombinase complex ending in thrombin generation and local clot formation. 

It is now widely accepted that atherosclerosis is a chronic inflammatory arterial disease associated with risk factors, platelet, and other blood cells activities and their interactions with subendothelial cells, Activated platelets release active components from citosol and induce the externalization of phosphatidylserine through the flip-flop mechanism (23) that supports the function of the prothrombinase complex ending in thrombin generation,... 

Variables (reg and integer types) declared locally within an always statement do not infer flip-flops. This may potentially lead to a functional mismatch between the Verilog HDL model and the synthesized netlist. Here is an example of a locally declared variable Temp that does not get inferred as a flip-flop. 

When synthesizing an asynchronous preset clear flip-flop, the recommendation is to assign only constant values under the asynchronous conditions. If a variable is asynchronously read, there is a potential for a functional mismatch to occur. Here is an example. 

The reason for the formation of the flip-flop cycle can be seen in its function as versatile junction for several homodromic chains which intersect in this place. These are three infinite chains, one in crystallographic c and two in b direction (see Figs. 18.13 and 18.17). Moreover, a short homodromic chain formed by W(13) and W(14) connects opposite corners of the flip-flop cycle and therefore gives rise to a homodromic cycle, Fig. 18.13 b. If the flip-flop cycle consisted of ordered O-H 0 bonds, other homodromic chains would have to be interrupted. 

In this chapter, we discuss the hydrogen bonding in structures where water is the sole or majority molecular species present. These are structures which are determined wholly or primarily by the hydrogen-bonding characteristics of the water molecules. They demonstrate the consequences of the dual hydrogen-bond donor-acceptor functionality, which, when combined with the cooperative and flip-flop dynamic properties of the hydroxyl groups, are essential for the formation of the hydration shells around the proteins and nucleic acids, and help to maintain their three-dimensional structures. 

Each of the terms A — F in Eq. 7.5 converts one of the basis functions— aa, a(3, (3a, (3(3—to the same or another function and is often said to link such pairs of functions. For example, A converts aa to aa because a is an eigenfunction of Iz. (a) Use the information in Section 2.3 to show the linkages for all four basis functions, (b) Convert the spin operators in term B to raising and lowering operators to demonstrate why this term is often called the flip-flop term. 

Membranes are structurally and functionally asymmetric, as exemplified by the restriction of sugar residues to the external surface of mammalian plasma membranes. Membranes are dynamic structures in which proteins and lipids diffuse rapidly in the plane of the membrane (lateral diffusion), unless restricted by special interactions. In contrast, the rotation of lipids from one face of a membrane to the other (transverse diffusion, or flip-flop) is usually very slow. Proteins do not rotate across bilayers hence, membrane asymmetry can be preserved. The degree of fluidity of a... 

All the data taken during the experiment, of which Figures 6-9 are representative examples, support the conclusion that most of the variance in an arbitrary cross-shelf space series can be modeled as superposition of step functions, ramp functions, binary flip-flops, and smaller-scale fluctuations. A biological and physical interpretation of these length scales is given in the discussion section. 

Figure 12.7 AhR surrogate with a bound aza-PAH as generated by Quasar. For clarity, the front section has been clipped. Areas colored in gray/brown represent hydrophobic properties areas in green H-bond donor functions areas in yellow indicate H-bond acceptors and purple domains correspond to H-bond flip-flops. No salt bridges are observed in this model as the ligands lack any charged groups. See color plates.

If step (2) results in an enhanced rate of transbilayer movement of the functional lipid because of the raised temperature, one would expect, upon bringing the pH back to 8 [step 3], to detect a new fast process accounting for the ester lipid that has moved from the interior to the exterior of the vesicles. This is in fact what the authors were able to monitor. By repetition of cycles (l>-(3), all the ester surfactant is eventually cleaved. By variation of the incubation time, a lifetime of the flip-flop process could be determined. The ti/2 data are reported in Table 3. Scrutiny of this table reveals that apart from the above-mentioned temperature of phase transition, the flip-flop process is also affected by the structure of the lipid backbone. For instance, dialkylammonium amphiphiles are much more mobile than those featuring a glycerolUke backbone increasing the length of the chain decreased the rate of... 

Fig. 16. The rope jumping motion of the N04 crown of the functionalized calix[4]arene 10 on the coordinated Ag(I) ion. The flip-flop movement results from the fact that the N04 ring has too small an aperture to encompass the metal ion. In a CH2CI2/CH3OH solution (4 1 v/v, deuterated solvents) the oscillating motion slows down with temperature and stops at -20 °C...

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