String-like

Figure 13.7 A diagram of the actin helix showing position of the tropomyosin. Both actin chains are flanked by tropomyosin molecules, which are long string-like molecules that span seven actin monomers. The troponin complex is attached to the tropomyosin but is not shown. From this diagram, it should be clear how the tropomyosin molecule can conceal the actin-binding sites for the myosin cross-bridges in the relaxed condition. A small conformational change in tropomyosin exposes the sites for attachment of the cross-bridges.

Garrahan and Chandler [230] have recently attempted to rationalize the string-like motion in supercooled liquids based on a completely different concept of dynamic facilitation, derived from the study of magnetic spin models originally developed by Fredrickson and Anderson [231]. Although these spin models seem to exhibit dynamic heterogeneity of some kind and slow relaxation processes, the slowing down of the dynamics in these models is entirely decoupled from the spin model s thermodynamics [116, 230]. In view... 

None of these arguments rules out the possibility of life in the fourth spatial dimension (i.e., a (4 + 1) universe). For example, stable structures may be possible if they are based on short distance quantum corrections to the 1/r potential or on string-like rather than point-like particles. 

Add 2 mL of nutrient broth containing 10 mM MgS04 to the tubes, and shake them vigorously at 37°C in an orbital shaker for 4-6 h or until lysis occurs. Lysis is complete when the solution becomes clear and contains string-like cell debris. Comparing the appearance of the infected culture with the control makes it easy to determine when this point is reached. 

By default, all 20 amino acids are used for exhaustive or random substitutions. If you want to restrict the amino acid alphabet, set the variable alphabet to a string like fwyh. In this example, only aromatic amino acids will be used. Another application is to prevent mutants that are to be expressed in Escherichia coli from having cysteines. 

We recognize that it would be interesting to find a self-consistent form of the well starting from the near-order structure of a liquid. A preliminary attempt was undertaken recently We considered attractive string-like interactions in an ensemble of the H-bonded molecules [12, 12a, 12b] see Section DC. This way of modeling may open new perspective for modeling of dielectric relaxation in aqueous media. 

Thus observation of ferroelectric domain reversal induced by indirect electron beam irradiation in LiNb03 bulk crystals represents a pronounced fdb effect. The reversed structure represents domain clusters consisting of multiple string-like domains with nanometer radius and 350 pm lengths. Fabricated one- and two-dimensional domain configurations could be used for a broad range of new 2-D as well as potential 3-D nonlinear photonic devices. 

The radius of string-like nanodomains observed under the fdb conditions is much smaller than its length, rm -C lm. Consequently, for the fdb phenomenon the shape invariant value should also be small. Equation (10.18) shows that the shape invariant has the lowest value if a ferroelectric material satisfies the following conditions ... 

In Table 10.2 below we summarize the calculated values of the shape invariant r 2//m and aspect ratio rm/lm of string-like domains in different fe crystals formed under the fdb conditions. The experimental parameters used for these calculations are U = 3kV (applied voltage), R = 50 nm (typical radius of curvature of the tip apex), d = 0.5 nm (distance between the tip apex and the sample surface). The calculated aspect ratios rm/lm are quite different for the chosen fe. 

Rotaxanes and polyrotaxanes are another type of compound consisting of string-like components threaded through ring-like components without covalent bonding (Fig. 11.19) and have received attention for a long time.46 Reported ring parts of... 

A massive polymer molecule that contains all the genetic information of the cell. It has a complicated structure containing many thousands of smaller units of amino acids, proteins, bases and sugars. It forms a double-twisted helix string-like molecule. The strands are held in position by cross links of hydrogen bonds from matching pairs of base materials on opposite chains. 

In the field of molecular knots templated by transition metal ions, another remarkable achievement deserves to be mentioned. Hunter and co-workers recently prepared a trefoil knot in a very satisfactory fashion by first wrapping a string-like molecule around a single transition metal ion with an octahedral coordination sphere (Zn2+) so as to obtain an open knotted structure and, subsequently, they could link the two ends of the string to form a real trefoil knot [38]. This nice piece of work again confirms the power of transition metals when it comes to preparing topologically novel species. 

The results summarized in this review represent the early stages of an ongoing research effort at 3M, which in effect is a three-dimensional approach to surface chemistry , i.e. an area of science between surface chemistry and solution chemistry. The sorption sites on the polymer are not representable as an immobile surface between solid and liquid domains, but rather are string-like polymer molecules undulating in a sea of liquid, so that the adsorption phenomenon must be represented three-dimensionally on a molecular scale rather than two dimensionally. 

The transformation of the lobular architecture is initiated and maintained by at least two histomorphological processes (i.) piecemeal necrosis and (2.) bridging necrosis, which provides string-like links between the central veins and the portal fields. Portocentral shunts, which are of significance for the fate of cirrhosis, make use of these bridges as routes for their development. During the course of time, these channels, which acquire solid basal membranes like capillaries, carry the portal blood directly to the venous flow-off. As a result, blood is withdrawn from the respective acini these areas become more susceptible to disruption and damage and are forced to restructure anew, (see chapter 35)... 

This virus species derived its name from the town of Coxsackie in the state of New York, where virological evidence thereof was successfully obtained for the first time. Coxsackie viruses are assigned to the picornavirus group, consisting at present of 23 A and 6 B types. Coxsackie hepatitis with mesenchymal reactions, portal infiltration and focal hepatocellular necrosis sometimes occurs, especially in infants. Cholestatic, predominantly centrolobular forms of the disease, can develop in adults. A lethal course is extremely rare. (66-68) The course of infection with the Coxsackie type B4 or B5 virus may give rise to the Fitz-Hugh-Curtis syndrome with the development of the typical violin string-like adhesive strands. (65) (s. fig. 24.2)... 

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