Temperature receptors

Flavor. The sensation produced by a material taken into the mouth, perceived principally by the senses of taste and smell, but also by the common chemical sense produced by pain, tactile, and temperature receptors in the mouth. 

Temperature receptors will respond exponentially to a sudden change in temperature. 

Once the model of a ligand-receptor complex is built, its stability should be evaluated. Simple molecular mechanics optimization of the putative ligand-receptor complex leads only to the identification of the closest local minimum. However, molecular mechanics optimization of molecules lacks two crucial properties of real molecular systems temperature and, consequently, motion. Molecular dynamics studies the time-dependent evolution of coordinates of complex multimolecular systems as a function of inter- and intramolecular interactions (see Chapter 3). Because simulations are usually performed at nonnal temperature (—300 K), relatively low energy barriers, on the order of kT (0.6 kcal), can... 

The Offshore and Coastal Dispersion (OCD) model (26) was developed to simulate plume dispersion and transport from offshore point sources to receptors on land or water. The model estimates the overwater dispersion by use of wind fluctuation statistics in the horizontal and the vertical measured at the overwater point of release. Lacking these measurements the model can make overwater estimates of dispersion using the temperature difference between water and air. Changes taking place in the dispersion are considered at the shoreline and at any points where elevated terrain is encountered. 

Even if the receptor by itself has high accuracy, the sensor may be unable to execute the measurement in a defined place. Quality and total accuracy depend on the combination of receptor, the converter for measured values, and mechanical protection. Mechanical protection can take the form of pockets in water and fluid and also assembly boxes which protect against pollution, humidity, and temperature in the surroundings or against electromagnetic transmissions and noise from power-supplied pipes and cables. 

Heated sources can cause strong updrafts that carry contaminants upward. Receptor hoods take advantage of this updraft, as shown in Fig. 10.31. The process shown to the left in Fig. 10.31 is at room temperature, while the process to the right in Fig. 10,31 is operating at elevated temperature. A canopy... 

The key variable in determining the applicability of a receptor hood to a particular source is the temperature of the heated source, and the resulting updraft. The temperature must be high enough to cause an appreciable updraft, or the hood will be ineffective. An estimate must be made of the total amount of buoyant airflow set in motion by the heated source the airflow through the hood must be greater than this buoyant airflow, in order to ensure complete contaminant capture. This principle is illustrated in Fig. 10.32, which shows the air spill that occurs when a hood s exhaust airflow is less than the thermal updraft airflow. 

A bolometer is essentially a thin blackened platinum strip in an evacuated glass vessel with a window transparent to the infrared rays it is connected as one arm of a Wheatstone bridge, and any radiation absorbed raises the temperature of the strip and changes its resistance. Two identical elements are usually placed in the opposite arms of a bridge one of the elements is in the path of the infrared beam and the other compensates for variations in ambient temperature. Both the above receptors give a very small direct current, which may be amplified by special methods to drive a recorder. 

Malignant hyperthermia (MH) is an autosomal-dominant pharmacogenetic disorder that is triggered by exposure to inhalation of general anesthetics, such as halothane. In susceptible individuals, these drugs can induce tachycardia, a greatly increased body metabolism, muscle contracture and an elevated body temperature (above 40°C) with a rapid rate of increase. Many cases of MH are linked to a gene for type 1 ryanodine receptor (RyRl). 

The TAAR receptor system has also been associated with body temperature regulation on the basis of putative thyroid hormone metabolites and their synthetic derivatives (thyronamines) activating TAAR1 in rodents. However, as these effects are only observed with thyronamine concentrations several orders of magnitude above physiological levels, and as the specificity of these compounds has not been determined, the physiological significance of these observations is unclear. 

On a global scale, the atmosphere serves as the major pathway for the transport and deposition of contaminants from emission sources to terrestrial and aquatic ecosystem receptors (22, 27). Once a contaminant is airborne, the processes of atmospheric di sion, transport, transformation, and deposition act to determine its fate. These processes are complex and the degree to which they influence the fate of a particular contaminant is dependent on its physico-chemical characteristics, the properties and concentrations of coexisting substances, and the prevailing meteorological conditions, including wind, precipitation, humidity, temperature, clouds, fog, and solar irradiation. 

After initial experiments demonstrating that the antiserum was capable of completely inhibiting the binding of [ H]PbTx-3 to its receptor site in rat brain membranes (Figure 9), we began studies designed to evaluate potential of the antiserum for prophylaxis and treatment of brevetoxin intoxication (34). The tethered rat model was used, and surgical implantations were identical to those described above. Heart rate, core and peripheral body temperatures, lead VIO ECG, and arterial blood pressure were monitored continuously. Respiratory rate was recorded each 5 min for the first 3 hr, then each 15 min until 6 hr. 

---