Crosstalk

For coaxial cables, the following electrical properties related to the dielectric constant of the core material and the dimensions determine the quaUty of the signal impedance, capacitance, attenuation, crosstalk, and time delay and velocity of propagation. 

The relationship of the dielectric constant of the cable insulation to crosstalk can be measured by testing two cables for crosstalk with the same dimension, but different insulation materials. The cable with the lower dielectric constant has less capacitance unbalance, thus resulting in lower crosstalk than the cable with the higher dielectric constant. 

The most important appHcation of fiber-optic laser-based communication is in long-distance telecommunications (92,93). Fiber-optic systems offer very high capacity, low cost-per-channel, light weight, small size, and immunity to crosstalk and electrical interference. 

Use fiber optic cable in preference to wires to reduce interference, crosstalk, and difference in ground potential at different location... 

In applications where numerous compressors are in close proximity, an additional measurement point on the base is useful for identifying structural resonance or crosstalk between the units. 

There is also crosstalk between the two pathways above the mitochondria. The BH3-only protein BID is cleaved by caspase-8 and -10 which yields truncated BID (tBED), the active pro-apoptotic fragment of BID. Thereby, even in cells in which the direct apoptosis pathway which result from death receptor crosslinking is blocked, e.g. by high expression levels ofthex-linked IAP (XIAP), the activity of tBED on mitochondria can result in the activation of caspase-3 because the IAP-imposed block on full caspase-3 activation and caspase-9 activity at the apoptosome is released by Smac/ DIABLO. 

Another type of NR crosstalk, which has only recently been recognized, is the so-called nongenomic actions of several receptors that induce very rapid cellular effects. Effectively, evidence has accumulated over several decades that steroid receptors may have a role that does not require their transcriptional activation, such as modifying the activity of enzymes and ion channels. While the effects of steroids that are mediated by the modulation of gene expression do occur with a time lag of hours, steroids can induce an increase in several second messengers such as inositol triphosphate, cAMP, Ca2+, and the activation of MARK and PI3 kinase within seconds or minutes. Many mechanistic details of these nongenomic phenomena remain poorly understood. Notably, controversy still exists as to the identity of the receptors that initiate the non-genomic steroid actions. However, it now appears that at least some of the reported effects can be attributed to the same steroid receptors that are known as NRs. 

Instead of activating transcription the cortisol-induced GR represses IL-6 synthesis and, even more surprisingly, repression does not involve the GRE elements, but rather the kB site (Fig. 1). It appeals that of a monomeric GR protein without itself touching the DNA interacts with the RelA component of NF-kB [3]. As a result GR blocks the action of NF-kB. The negative interference by this crosstalk is not restricted to NF-kB, it occurs also with AP-1 and CREB, and with several other transcription factors not relevant for IL-6 expression. A nuclear isoform of the LIM protein Trip6 mediates the interaction between these factors and is required for the inhibitory GR function. This interesting negative crosstalk is part of the immune-suppressive action of cortisol. 

Figure 7. Influence of the polarization preservation in a fibre interferometer. Right Standard fibre use leads to a complex pulse response associated with fringe degradations with polarization crosstalk. Left Using polarization preserving fibre, the two polarization modes give rise to contrasted fringes and can be separated using a polarizer.

Despite the above precautions, it is still possible that NT spillover and extrasynaptic action may occur and indeed could be required in some instances. Thus the diffusion of glutamate beyond the synapse could activate extrasynaptic high-affinity NMDA or metabotropic receptors (Chapter 9) to produce long-lasting effects to maintain activity in a network. This may be important in long-term potentiation and memory effects. Crosstalk between synapses could also act as a back-up to ensure that a pathway functions properly (see Barbour and Hausser 1997). 

Laule, O. et al.. Crosstalk between cytosolic and plastidial pathways of isoprenoid biosynthesis in Arabidopsis thabana, Pmc. Natl. Acad. Sci. USA 100, 6866, 2003. 

Muller, N. Schwarz, M. J. (2006). Neuroimmune endocrine crosstalk in schizophrenia and mood disorders. Expert Rev. Neurother., 6, 1017-38. 

Each of these pathways involves a kinase cascade resulting in the phosphorylation and activation of the MAP kinase family member. Each contains a dual phosphorylation site (TEY, TPY, or TGY) and the central residue in the motif characteristic of the class, as shown in Table 8.1. It is evident that cells are endowed with parallel signal-transduction pathways and that they may operate individually or in combination to initiate specific patterns of gene expression. Additionally, crosstalk between the pathways undoubtedly occurs. None of these pathways has a unique function it is more likely that the combination of pathways that are activated (or silenced) together with the... 

Garcia-Ovejero, D., Azcoitia, I., Doncarlos, L. L., Melcangi, R. C. Garcia-Segura, L. M. (2005). Glia-neuron crosstalk in the neuroprotective mechanisms of sex steroid hormones. Brain Res. Brain. Res. Rev. 48, 273-86. 

Figure 16. The variation (crosstalk) of modulation index with filter bandwidth, when the measurement cell contains a high concentration (0.05 Bar partial pressure) of H20 vapour impurity (both cells are 1 m in length cell at 1 Bar and 20 °C, and the reference cell contains 100% C02 gas).

Crosstalk has been discussed fairly extensively, as one of a series of interference phenomena that can lead to a different kind of control of molecular transport than has been discussed in Sect. 7.4. It is also possible to observe intramolecular interference effects. For example, with cross-conjugated molecules [163] or benzene dithiol linked in the 1,3 (or meta) configurations [164-171], both are expected to show substantially reduced transport. 

These interference patterns are wonderful manifestations of wave function behavior, and are not found in classical electronics or electrodynamics. Since the correspondence principle tells us that quantum and classical systems should behave similarly in the limit of Planck s constant vanishing, we suspect that adequate decoherence effects will change the quantum equation into classical kinetics equations, and so issues of crosstalk and interference would vanish. This has been... 

Figure 5 Crosstalk between pixels due to multiple reflections between the window and the surface of the CCD chip. A photon coming from a initially should hit the pixel labeled i. If it is reflected off the surface, it bounces back toward the window and will be absorbed by pixel j as if it were coming from b.

A number of proteins that inhibit the JAK-STAT function have also been identified. These include members of the so-called SOCS/Jab/Cis family and the PIAS family of regulatory proteins. Several appear to function by inhibiting the activation of various STATs, although the mechanisms by which this is achieved remain to be elucidated in detail. The JAK-STAT pathway likely does not function in isolation within the cell. JAKs are believed to activate elements of additional signalling pathways, and STATs are also likely activated by factors other than JAKs. As such, there may be considerable crosstalk between various JAK- and/or STAT-dependent signalling pathways. 

Voutsinos-Porche, B., Bonvento, G., Tanaka, K. et al. Glial glutamate transporters mediate a functional metabolic crosstalk between neurons and astrocytes in the mouse developing cortex. Neuron 37 275-286, 2003. 

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