Noninvasiveness

Biosensors (qv) and DNA probes ate relatively new to the field of diagnostic reagents. Additionally, a neat-infrared (nit) monitoring method (see Infrared TECHNOLOGY AND RAMAN SPECTROSCOPY), a teagenfless, noninvasive system, is under investigation. However, prospects for a nit detection method for glucose and other analytes ate uncertain. 

The deterrnination of surface temperature and temperature patterns can be made noninvasively using infrared pyrometers (91) or infrared cameras (92) (see Infrared technology and raman spectroscopy). Such cameras have been bulky and expensive. A practical portable camera has become available for monitoring surface temperatures (93). An appropriately designed window, transparent to infrared radiation but reflecting microwaves, as well as appropriate optics, is needed for this measurement to be carried out during heating (see Temperature measurement). 

The biological and medical sciences are ripe for iastmmentation advances. Whereas most immunoassays (qv) use radioactive materials, the implementation of chemiluminescent methods, enzyme techniques, and electrochemical methods is expected to become more important. New and better noninvasive methods of iavestigation are expected to become more routine. In addition, real-time measurements, whereby analyses of a number of... 

The objective ia any analytical procedure is to determine the composition of the sample (speciation) and the amounts of different species present (quantification). Spectroscopic techniques can both identify and quantify ia a single measurement. A wide range of compounds can be detected with high specificity, even ia multicomponent mixtures. Many spectroscopic methods are noninvasive, involving no sample collection, pretreatment, or contamination (see Nondestructive evaluation). Because only optical access to the sample is needed, instmments can be remotely situated for environmental and process monitoring (see Analytical METHODS Process control). Spectroscopy provides rapid real-time results, and is easily adaptable to continuous long-term monitoring. Spectra also carry information on sample conditions such as temperature and pressure. 

Radiometry. Radiometry is the measurement of radiant electromagnetic energy (17,18,134), considered herein to be the direct detection and spectroscopic analysis of ambient thermal emission, as distinguished from techniques in which the sample is actively probed. At any temperature above absolute zero, some molecules are in thermally populated excited levels, and transitions from these to the ground state radiate energy at characteristic frequencies. Erom Wien s displacement law, T = 2898 //m-K, the emission maximum at 300 K is near 10 fim in the mid-ir. This radiation occurs at just the energies of molecular rovibrational transitions, so thermal emission carries much the same information as an ir absorption spectmm. Detection of the emissions of remote thermal sources is the ultimate passive and noninvasive technique, requiring not even an optical probe of the sampled volume. 

Electrotransport technology offers a number of benefits for therapeutic appHcations, including systemic or local adininistration of a wide variety of therapeutic agents with the potential adininistration of peptides and proteins long-term noninvasive administration, improving convenience and compliance controlled release, providing a desired deflvery profile over an extended period with rapid onset of efficacious plasma dmg levels and in some cases reduced side effects and a transport rate relatively independent of skin type or site. Additional benefits include easy inception and discontinuation of treatment, patterned and feedback-controlled deflvery, and avoidance of first-pass hepatic metaboHsm. 

The ultimate model is the human in the clinical situation. Translational medicine with noninvasive imaging techniques and biomarkers is now able to furnish valuable information that can be used in the initial discovery process to produce better defined drugs. 

The role of the platelet integrin GPIIb/IIIa receptor and its potential utility as a radio-diagnostic agent in the rapid detection of thromboembolic events has been demonstrated [6]. This approach may be useful for the noninvasive diagnosis of various thromboembolic disorders. 

Inhaled NO has been used for treatment of persistent pulmonary hypertension of newborn infants, critical respiratory failure of preterm infants, and acute hypertension of adult cardiac surgery patients. PDE-5 inhibitors such as sildenafil are also effective for treatment of pulmonary hypertension. The combination of PDE-5 and NO inhalation yields additive beneficial effects on pulmonary hemodynamics. On the other hand, measurement of exhaled NO is a noninvasive and reproducible test that is a surrogate measure of airway inflammation in patients with bronchial asthma. 

Magnetic resonance imaging is a noninvasive structural technique for complex systems of molecules, such as people. In its simplest form, MRI portrays the concentration of protons in a sample. If the sample—which may be a living human body—is exposed to a uniform magnetic field in an NMR spectrometer and if we work at a resolution that does not show any chemical shifts or fine structure, then the protons... 

For these reasons the Cooperative Hypothesis seems to be a plausible alternative to the Latch Bridge Hypothesis. Given that computer calculations of the behavior of various hypothetical schemes are now possible, an independent, noninvasive measure of distribution of myosin among the states would be of great use for further understanding of crossbridge kinetics. 

Advancing the field of process engineering. Important generic goals for research include the development of separation processes for complex and fragile bioproducts the design of bioreactors for plant and mammalian tissue culture and the development of detailed, continuous control of process parameters by rapid, accurate, and noninvasive sensors and instruments. 

The development of rapid, accurate, and noninvasive online measurement sensors and instraments is a high-priority goal in the commercialization of biotechnology (Figure 3.4). Some of these instraments will build on analytical methods now used in catalysis and other surface sciences, such as... 

While the mechanical performance of artificial materials in the human body can be predicted with some rehabihty, forecasting their biological performance is difficnlt. The problem of interactions at surfaces has already been mentioned. Research frontiers also include developing ways to simulate in vivo processes in vitro and extending the power and apphcability of such simulations to allow for better prediction of the performance of biomedical materials and devices in the patient. Fundamental information on the correlation between the in vivo and in vitro responses is limited. Chemical engineers might also make contribntions to the problem of noninvasive monitoring of implanted materials. 

The multiphase fluid systems of interest are often opaque, and thus noninvasive techniques based on optical methods or using laser beams are not effective. Various experimental techniques are available and continue to be developed to characterize opaque multiphase flows. 

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