Dual-wavelength

Biegert, J., Diels, J.-C., and Milonni, P. W., 2000, Bi-chromatic 2-photon coherent excitation of sodium to provide a dual wavelength guide star. Optics... 

Ratzlaff, K. L., and bin Darus, H., Optimization of Precision in Dual Wavelength Spectrophotometric Measurement, Anal. Chem. 51, 1979, 256-261. 

The identification of synthetic colorants (pure or mixtures) in foods is usually carried out using spectrophotometry but the resolution of complex mixtures in food requires a previous separation of extract components by SPE and chromatographic techifiques. Dual wavelength, solid phase, and derivative spectrophotometric methods combined with chemometric approaches have been used. ... 

Such a result may be put in parallel with the determination of the bound cations obtained by ion-specific electrode or dual-wavelength spectrophotometric method, and analysed in terms of cooperativity [7,29,31]. 

Keywords Dual-wavelength ratiometry Electrochromism Ion-transporting membrane proteins Membrane dipole potential Phototoxicity... 

As mentioned above, in all photophobic action spectra measured so far additional peaks and/or shoulders occur at 565 and/or 615 nm, besides the chlorophyll a peaks, indicating the participation of phycobiliproteins and, hence, PS II in the active light absorption (Fig. 4). Moreover, activity of both PS I and PS II was confirmed by inhibitor experiments (see reviews by Nultsch 10°),Nultsch and Hader102), and Hader47)) and also with the aid of a dual wavelength technique39 40 101), described in detail below. 

Stamm C., Dangel R., Lukosz W., Biosensing with the integrated-optical difference interferometer dual-wavelength operation, Opt.Commun. 1998 153 347-359. 

Cubeddu R., Pifferi A., Taroni P., Torricelli A., Valentini G., Compact tissue oximeter based on dual-wavelength multichannel time-resolved reflectance, Appl. Opt. 1999 38 3670. 

Dual wavelength imaging imaging at two wavelengths simultaneously means that there will be two separate arrays of detectors fed via a dichroic beam splitter. 

Lipinski CA, Lombardo F, Dominy BW, Feeney PJ (1997) Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv Drug Del Rev 23 3-25 US Food and Drug Administration (2007) Challenge and opportunity on the critical path to new medical products, http //www.fda.gov/oc/initiatives/ criticalpath/whitepaper/html, Cited 6 February 2007 White JD (2003) A dual wavelength optical fluorescence analyser, WO/2003/ 048744... 

Oxy- and deoxy-hemoglobins are mainly of interest because they are related to the regional cerebral blood flow (rCBF). The focal change in rCBF determines the activation state. The term activation usually refers to the focal increase in rCBF whereas a decrease is called deactivation [78]. With the dual wavelength approach, one can derive two simultaneous equations to be solved for each of the two chromophore concentration changes. To this end, Equation (4) is split into two parts, separating the contributions from HbO and Hb. Equation (4) is then, rewritten as... 

N. Okui and E. Okada. Wavelength dependence of crosstalk in dual-wavelength measurement of oxy- and deoxy-hemoglobin. Journal of Biomedical Optics, 10(l) 011015-l-011015-8, 2005. 

Another feature is that the absence of spectral change precludes ratiometric measurements. However, dual-wavelength Cl sensors have been constructed. For instance, in compound A-6 (Figure 10.30), 6-methoxyquinolinium (MQ) as the Cl -sensitive fluorophore (blue fluorescence) is linked to 6-aminoquinolinium (AQ) as the Cl--insensitive fluorophore (green fluorescence), the spacer being either rigid or flexible. 

Fig. 10.30. Dual-wavelength chloride ion sensors (Jayaraman S. et al. (1999) Am.J. Physiol. 276, C747).

Farrens and Song<40) have replaced the original spark source with a picosecond diode laser in a multiplexed dual wavelength T-formatfluorometer.(41)With an overall instrumental response width of ca. 300 psec full-width half-maximum (FWHM), near-IR fluorescence lifetimes as low as 75 psec in the case of l,l -diethyl-4,4 carbo-cyanine iodide (DCI) (excitation 660 nm) and decay components as low as 48 psec in the case of 124 kDa oat phytochrome (excitation 752 nm) were reported. 

FIGURE 2 HPLC chromatogram of Drug A and Drug B at dual channel (dual wavelength Xj only). 

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