Selectivity switch

Watts KT, Mijts BN, Lee PC, Manning AJ, Schmidt-Dannert C (2006) Discovery of a substrate selectivity switch in tyrosine ammonia-lyase, a member of the aromatic amino acid lyase family. Chem Biol 13(12) 1317-1326... 

Enhancement of Separation. For some applications, a single column cannot adequately perform the complete separation of all the desired components. By connecting a second column and detector system in series with the normal one, components not resolved on the first column can be selectively switched into the second column for further separation and then detected on the second detector. If the columns are of the same liquid phase, shorter... 

The site selectivity switch, that is the site to which BF3 coordinated carbonyl rearrangement occurs, in the skeletal rearrangements of cyclobutene-fused diarylhomoben-zoquinones (43) is reported to result from higher order complexation. Thermodynamic... 

Generally, octatriene formation is favored by higher temperatures, higher phosphine and/or butadiene concentrations and, importantly, by an increase in steric bulk of either the ligand or the nucleophile. Indeed, Harkal et al. showed a selectivity switch from telomerization products to 1,3,7-octatriene formation by altering the steric demand of the /V-heterocyclic carbene ligand in the reaction of butadiene with isopropanol under further identical reaction conditions [48]. For the more basic nucleophiles, such as the alcohols, the telomer products are stable under experimental conditions, i.e. product formation is irreversible, but for more acidic substrates such as phenol, product formation is reversible and more 1,3,7-octatriene will be formed after the substrate has been depleted. 

With a quite specific class of compounds, Belmont and coworkers reported a selectivity switch when changing the catalyst.44 The reaction is shown in Scheme 12.25. 

In terms of the specific components, advancement to each step of the cycle is possible because the absorption of light and the transfer of excitation energy to P680 leads to formation of an extremely strong oxidant. The preparation of an analogous durable synthetic system that can be selectively switched into a strong oxidizing form... 

Fig. 16 Adaptation to shape change by component selection. Switching between W and U shapes of a component, under metal cation binding and removal, induces interconversion between polymer and macrocycle states with selection of the preferred component...

Optical Switches In telecommunication, an optical switch is a switch that enables signals in optical fibers or integrated optical circuits (lOCs) to be selectively switched from one circuit to another. In biology, there are several... 

While a full characterization of these intermediates would provide significant mechanistic information, this task is not simple from an experimental point of view since usually only spectroscopic techniques can be enq>loyed and the relationships between spectroscopic parameters and structural features is quite indirect. Furthermore, the measured quantities often result from the superposition of different contributions which are very difficult, when not impossible, to separate. In such circumstances, quantum mechanical computations can provide an invaluable support to experiment since they are able to selectively switch a number of interactions on and off, thus allowing an unbiased evaluation of the effect of different contributions. 

The two preceding functions must be executable at the molecular level with full addressability. That is, it must be possible to selectively switch or address an individual molecule. 

At present, the aim is to ensure that a humoral response is generated. For mucosal vaccines, IgA may be more appropriate.21516 T cell-mediated responses may also be considered, and advances in knowledge and the development of different types of vaccines and/or adjuvants suggest that cell-mediated responses may be just as or more important than the humoral response, when considering the selection of species. Adjuvants can selectively switch the T helper cell response, which may influence a protection or pathology dependent response (see Section 19.2.5). However, the current understanding and interpretation of such data are limited in terms of predicitivity, and there are also limitations in the immunoassays developed for species routinely used in nonclinical testing. This is a key area where further development is required. 

The device is readily applicable to multiple installations of different line resistance. For multiple-point recorders and indicators as many resistances BC may be employed as there are couples. These may be inexpensive rheostats having a resistance of approximately 15 ohms each located in each couple line between the couple and the selective switch. These rheostats may be adjusted in the manner described whenever convenient or necessary. The following illustrates a suitable proportioning of resistance for a 300 ohm indicator. 

Figure 13 illustrates a multiple thermocouple installation connected to a single indicator. Compensating lead wires are carried from the couples to a conveniently located cold-junction box. The temperature of this box is thermostatically controlled. From the cold-junction box copper wires are carried to the terminal block and selective switch illustrated. A common return has been employed between the cold-junction box and the switchboard. In general it is preferable to use individual return wires for each couple. The switchboard illustrated is designed for six couples. By pressing one of the buttons shown any desired couple is connected directly to the indicator. 

It is merely necessary to have a uniform temperature in the box. This is secured when the box is constructed of heavy metal. The electromotive force developed at the junctions of compensating leads and copper leads is compensated for by a common junction in the opposite direction inserted between the selective switch... 

Fernandez A, Scott RL, Berry RS (2006) Packing defects as selectivity switches for drug-based protein inhibitors. Proc Natl Acad Sci USA 103 323-328... 

The key concept is that of differentiation this is the process by which the whole genome in each cell is selectively switched off or silenced in specific places on the chromosomal DNA, leaving only a subset of all possible genes available to be translated into proteins. It is the characteristics of the proteins in the set of all proteins in a cell, and their relative amounts, that are the fundamental determinants of the final nature of a cell, and hence what tissue name we might assign to it. 

More practically we may be able to effect elimination by isolating just part of the system responsible for the risk. Most HIT systems are modular and at some level can be selectively switched off either through configuration or by the manufacturer updating the system code. One must examine however whether isolating the functional unit has the potential to introduce additional hazards by way of it being unavailable. An eliminative strategy is often only an option when the functionality... 

The selection of drive mode includes a mode selection switch and indicator lamp. The drive mode selection switch is located on the operating panel. It can provide the different mode selection according to the different type of car. 

Voltage select switch Flat panel displays... 

Pyajt, A., L. Dalton, and A. Chen. 2005. Novel wavelength selective switch based on electro-optic polymer microrings. Proc SPIE 5935 W1—14. 

Fig. 6.13. Two-dimensional CID array using the two well unit cell. The horizontal scan register controls column select switches and the voltage to provide charge injection is capacitively coupled in from the injection driver. By manipulating the voltages provided by the scan registers the CID array can be read out in any desired sequence...

Fig. 6.17. Series-parallel scan IR CID with one preamplifier per column. All the columns are read out simultaneously. This lowers the readout speed and avoids the column select switches shown in Fig. 6.13...

---