Response profiles

Also notable is the unique sweetness response profile of fmctose compared to other sweeteners (3,4). In comparison with dextrose and sucrose, the sweetness of fmctose is more quickly perceived on the tongue, reaches its iatensity peak earlier, and dissipates more rapidly. Thus, the sweetness of fmctose enhances many food flavor systems, eg, fmits, chocolate, and spices such as cinnamon, cloves, and salt. By virtue of its early perception and rapid diminution, fmctose does not have the flavor-maskiag property of other common sugars. 

Calcium channel blockers normalize the blood pressure in about 80% of hypertensive patients older than 60 years of age, 50% of those between 40 and 60 years of age, and only 20% of patients under 40 years of age. Thus calcium channel blockers are best for patients who are elderly and have low PRA and mosdy ineffective in patients who have high PRA. This responsiveness profile is very similar to that of the diuretics. 

OWENS has prepared antibodies to PCP in goats. When administered to mice the PCP levels in blood rose tenfold as an antibody-bound form that was readily excreted in urine. BROWNE tested the selfadministration by rats of 1,000 compounds related (and not related) to PCP, some of which produced PCP-like effects. One compound that was self-administered prevented the entrance of PCP into brain. BALSTER gave a general review of the effects produced by PCP in laboratory animals and showed that some effects were similar to those produced by amphetamine, some to barbiturates, and some to antipsychotics. This response profile makes PCP a unique drug that stands alone in its complex effects and toxicity. 

After about 30 training sessions, most animals had acquired the PCP vs. vehicle discrimination, as evidenced by at least 9 out of 10 consecutive sessions during which the rats emitted fewer than 20 responses before the first reinforcement. Following this acquisition of the discrimination, the animals were tested in a random order with different doses of PCP. Figure 1 shows the dose-response profile for PCP discrimination in different groups of rats trained to discriminate 1.0, 1.78 or 3.2 mg/kg of PCP from vehicle. At low doses of PCP few, if any, rats chose the lever previously paired with PCP (i.e., most rats chose the vehicle-associated lever). 

Bowman EP, Campbell JJ, Soler D, et al. Developmental switches in chemokine response profiles during B cell differentiation and maturation. J Exp Med 2000 191 1303-1318. 

Iellem A, Mariani M, Lang R, et al. Unique chemotactic response profile and specific expression of chemokine receptors CCR4 and CCR8 by CD4(+)CD25(+) regulatory T cells. J Exp Med 2001 194 847-853. 

F. Langenbucher, IYIC Indices for comparing release and response profiles, Drug Dev. And Ind. Pharm., 25, 1223 (1999). 

Another approach to analyze the multi-sensor array responses is the ensemble approach11, which does not require decoding and therefore, speeds up the identification process. The analysis in this approach uses combined response profiles of the entire undecoded array as a single response (Figure 6). 

An important demonstrated application of this artificial nose system is the high-speed detection of low levels of explosives and explosive-like vapors. Several sensors, based on Nile Red attached to silica microspheres, show high sensitivity to nitroaromatic compounds (NAC) within a mixture12. Different fluorescence response profiles were observed for several NAC s, such as 1,3,5-trinitrotoluene (TNT) and 1,3-dinitrobenzene (DNB), despite their similar structures. These responses were monitored at low concentrations of the NAC vapors (ca. 5 ppb) and at short vapor exposure... 

Figure 6. Response profiles from three different sensor types, (a) Concatenated Responses of each of the individual sensor types (decoded array), (b) The collective response (undecoded array). Reprinted with permission from ref. 11. Copyright 2003 American Chemical Society.

High-speed detection is a necessity for many artificial nose applications. In one study123, it was shown that even at short exposure times (<1 sec), the nose could identify different vapors and the responses were reproducible. Figure 8 demonstrates this quality, when three high-speed exposures (0.38s exposure time) produced reproducible response profiles. 

In addition, a linear dependence was found between the concentration of DNB and its fluorescence response profile. All these characteristics demonstrate that this sensor array is suitable for use in detecting explosive vapors. 

Figure 7. Simultaneously monitoring vapor signatures of 1000 sensors for 2,4-DNT, 1,3-DNB, and TNT vapor strips at 8% saturated vapor levels. The (noisy) responses for 250 individual sensors are compared to the averaged response profile for 1000 individual sensors. Reprinted with permission from ref. 12a. Copyright 2000 American Chemical Society.

Figure 8. Seventy-six sensor beads (Jupiter C4/Nile Red) monitored to show that the average responses for three consecutive 0.38-s exposures of 50% saturated vapor levels result in reproducible and high-speed response profiles. The sensors are positioned on the distal tip of an optical imaging fiber and relative analyte concentrations are 0.5 and 18700 ppm for 1,3-DNB and toluene, respectively. Reprinted with permission from ref 12a. Copyright 2000 American Chemical Society.

Figure 6. Fluorescence decay profiles of trans-7,8-dihydroxy-7,8-dihydro-BP and 8,9,10,11-tetrahydro-BA measured at 23 °C with and without native DNA. Taken from refs. 14 and 15. The upper left-hand corner contains an instrument response profile. Emission and excitation wavelengths, lifetimes, and values of x2 obtained from deconvolution of the lifetime data are also given.

Electrochemical detection is sensitive and selective, and it gives useful information about polyphenolic compounds in addition to spectra obtained by photodiode array detectors. Differences in electrochemically active substituents on analogous structures can lead to characteristic differences in their voltammetric behavior. Because the response profile across several cell potentials is representative of the voltammetric properties of a compound, useful qualitative information can be obtained using electrochemical detection (Aaby and others 2004). 

Dalton, Pamela, and Gary K. Beauchamp. Establishment of Odor Response Profiles Ethnic, Racial and Cultural Influences. Philadelphia, PA Monell Chemical Senses Center, February 4, 1999. 

Note that if i = N, equation 19.4-45 generates the response profile for the entire network. Furthermore, from the definition of F(t) for a step change ... 

Fig. 4.12 Dynamic response profiles at different wavelengths upon replicate (n 3) exposures to vapors at 0.02 P/Pq concentration (a) water, (b) ACN, (c) DCM, and (d) toluene. Wavelengths 770 nm circles), 835 nm squares), and 870 nm diamonds). Reprinted from Ref. 15 with permission. 2008 Institute of Electrical and Electronics Engineers...

Labra, A., Brann, J. H. and Fadool, D. A. (2005) Heterogeneity of voltage- and chemosignal-activated response profiles in vomeronasal sensory neurons. J. Neurophysiol. 94, 2535-2548. 

Dissolution/release profiles in vitro, as well as body response profiles in vivo (e.g., plasma concentrations or... 

Performance comparisons with a Clark-type sensor demonstrated the applicability of the optical sensor in monitoring dissolved oxygen (DO) levels in a bioreactor.<73) Figure 13.11 shows the response profiles of the optical sensor and Clark-type electrode... 

---