Modulation of phase

A descriptive framework is proposed, consisting of 7 modules (of phases) which together should form an (ideal ) near miss management system. 

Phytochemicals not only are subject to xenobiotic metabolism, but can also modulate the latter. Knowledge on the modulation of phase 1/2 enzyme expression by phytochemicals is of crucial importance, since metabolism by P450 enzymes can not only... 

In terms of bioactivity, monodictysin B was shown to inhibit cytochrome P450 1A with an /C50 value of 3.0 iM. Both monodicysins B and C were shown to effect the induction of NAD(P)H quinone reductase (QR) in Hepa cells. The modulation of Phase II detoxifying enzymes such as QR is important for both the metaboUsm and excretion of carcinogens, and this target enzyme is employed frequently in the study of potential cancer chemopreventive agents 637) (640). 

According to seminal scheme proposed by Lee Wattenberg, modulation of phase I drug-metabolizing enzymes and induction of phase II detoxifying enzymes have been inferred as an important strategy largely responsible for detoxification of... 

Guyonnet, D., Siess, M.H., Le Bon, A.M. et al. (1999) Modulation of phase 11 enzymes by organo-sulphur compounds from Allium vevegtables in rat tissues. Toxicol. Appl. Pharmacol., 154, 50-58. 

Flow which fluctuates with time, such as pulsating flow in arteries, is more difficult to experimentally quantify than steady-state motion because phase encoding of spatial coordinate(s) and/or velocity requires the acquisition of a series of transients. Then a different velocity is detected in each transient. Hence the phase-twist caused by the motion in the presence of magnetic field gradients varies from transient to transient. However if the motion is periodic, e.g., v(r,t)=VQsin (n t +( )q] with a spatially varying amplitude Vq=Vq(/-), a pulsation frequency co =co (r) and an arbitrary phase ( )q, the phase modulation of the acquired data set is described as follows ... 

The transition from smectic A to smectic B phase is characterized by tire development of a sixfold modulation of density witliin tire smectic layers ( hexatic ordering), which can be seen from x-ray diffraction experiments where a sixfold symmetry of diffuse scattering appears. This sixfold symmetry reflects tire bond orientational order. An appropriate order parameter to describe tlie SmA-SmB phase transition is tlien [18,19 and 20]... 

For higher accuracy, a method involving ampHtude modulation of a continuous laser beam is used. Again, a detector receives light reflected from the object where the distance is to be measured. The phases of the modulation in the outgoing beam and in the reflected return are compared. For a total phase shift A( ) between the two signals, the range R is... 

Metallurgy. Lithium forms alloys with numerous metals. Early uses of lithium alloys were made in Germany with the production of the lead alloy, BahnmetaH (0.04% Li), which was used for bearings for railroad cars, and the aluminum alloy, Scleron. In the United States, the aluminum alloy X-2020 (4.5% Cu, 1.1% Li, 0.5% Mn, 0.2% Cd, balance Al) was introduced in 1957 for stmctural components of naval aircraft. The lower density and stmctural strength enhancement of aluminum lithium alloys compared to normal aluminum alloys make it attractive for uses in airframes. A distinct lithium—aluminum phase (Al Li) forms in the alloy which bonds tightly to the host aluminum matrix to yield about a 10% increase in the modules of elasticity of the aluminum lithium alloys produced by the main aluminum producers. The density of the alloys is about 10% less than that of other stmctural aluminum alloys. 

Modulation of second-messenger pathways is also an attractive target upon which to base novel antidepressants. Rolipram [61413-54-5] an antidepressant in the preregistration phase, enhances the effects of noradrenaline though selective inhibition of central phosphodiesterase, an enzyme which degrades cycHc adenosiae monophosphate (cAMP). Modulation of the phosphatidyl iaositol second-messenger system coupled to, for example, 5-HT,, 5-HT,3, or 5-HT2( receptors might also lead to novel antidepressants, as well as to alternatives to lithium for treatment of mania. Novel compounds such as inhibitors of A-adenosyl-methionine or central catechol-0-methyltransferase also warrant attention. 

Circular dichroism employs standard dispersive or interferometric instmmentation, but uses a thermal source that is rapidly modulated between circular polari2ation states using a photoelastic or electro-optic modulator. Using phase-sensitive detection, a difference signal proportional to the absorption difference between left- and right-polari2ed light, AA is recorded as a function of wavenumber. Relative differential absorptions... 

The essential differences between sequential-modular and equation-oriented simulators are ia the stmcture of the computer programs (5) and ia the computer time that is required ia getting the solution to a problem. In sequential-modular simulators, at the top level, the executive program accepts iaput data, determines the dow-sheet topology, and derives and controls the calculation sequence for the unit operations ia the dow sheet. The executive then passes control to the unit operations level for the execution of each module. Here, specialized procedures for the unit operations Hbrary calculate mass and energy balances for a particular unit. FiaaHy, the executive and the unit operations level make frequent calls to the physical properties Hbrary level for the routine tasks, enthalpy calculations, and calculations of phase equiHbria and other stream properties. The bottom layer is usually transparent to the user, although it may take 60 to 80% of the calculation efforts. 

Figure 4-18 Phase modulation of a PWM full-bridge converter.

RAIRS is a non-destructive infrared technique with special versatility - it does not require the vacuum conditions essential for electron spectroscopic methods and is, therefore, in principle, applicable to the study of growth processes [4.270]. By use of a polarization modulation technique surfaces in a gas phase can be investigated. Higher surface sensitivity is achieved by modulation of the polarization between s and p. This method can also be used to discriminate between anisotropic near-sur-face absorption and isotropic absorption in the gas phase [4.271]. 

Frequency converters constructed for use with three-phase motors less than 4 kW can therefore be delivered with a single-phase supply from the electrical mains. For greater power requirements, it is most common to use a three-phase power supply. Through switches and potentiometers or the programming module of the frequency converter, the important parameters of electrical motors can be adjusted as needed. 

The modulated phase disappears for head sizes smaller than 1.14c7. Modulations of this kind have not been observed in experiments so far. 

---