Toxic effect sensors

Enzyme Sensors for Inhibitors - Toxic Effect Sensors... 

PXR has been demonstrated to act as an LCA sensor and plays an essential role in detoxification of cholestatic bile acids [11,61]. Studies in different animal models showed that activation of PXR protected against severe liver damage induced by LCA. Pretreatment of wild-type mice, but not the PXR-null mice, with PCN reduced the toxic effects of LCA. Moreover, genetic activation of PXR by expressing the activated... 

In addition to the standard laboratory protection, such as safety goggles and chemically resistant butyl rubber gloves, a personal HF gas monitor with audible alarm and a safety sensor for liquids, as described in Section 10.4, are commercially available [2], For detailed information about the toxic effects of HF, see references Fi5, Wa8 and Re4. 

A general problem of microbial BOD-sensors could be poisoning of the cells by toxic substances in wastewater. One possibility to reduce or even to eliminate toxic effects on BOD-sensors is achieved by shortening measuring times down to not more than 1 min, in this way preventing toxic effects on the cells because of the short time of exposure to the toxic agents. 

Ancillary ligands can dramatically improve detection strategies based on sensitized Ln luminescence by stabilizing the lanthanide to pH variations. Such enhancements in stability and reproducibility allow the use of lanthanide sensors in situ and also potentially in vivo, where free lanthanide ions might precipitate and/or have toxic effects. 

In addition to laboratory blood analyzers and portable point-of-care devices, which require blood collection, continuous monitoring of ion activities in a blood stream via implanted ion-selective electrodes is of great interest. The term biocompatibility refers to the ability of a sensor not to cause toxic or injurious effects while being in contact with living tissue. As dealing with any foreign object introduced into the human body, biocompatibility and hemocompatibility particularly are the most important requirements. 

While nicotine is the primary active pharmacological agent, tobacco has been shown to be a particularly effective vehicle for delivery of nicotine (US Food and Drug Administration 1995 Hurt and Robertson 1998 Slade et al. 1995 World Health Organization 2001). In fact, published research has determined that tobacco-delivered nicotine is not only more toxic, but more addictive than nicotine in a pure form (e.g., nicotine replacement therapy) (Henningfleld et al. 2000 Royal College of Physicians 2000). As noted by a BW scientist in 1990 Nicotine alone in smoke is not practical, nor are extreme tar/nicotine ratios, since nicotine is too irritating -other substances are required for sensoric reasons (Baker 1990). 

These results are consistent with previous measurements which showed that CO concentration was lowest at the combustor operating conditions that most efficiently reduced the overall emission of toxic gases. Thus a measurement of CO concentration can serve as an effective indicator of combustor performance. The results demonstrate the applicability of multiplexed diode laser sensors for rapid, continuous measurements and control of multiple flowfield parameters, including trace species concentrations, in high-temperature combustion environments. 

Without doubt, the favored field of application of microbial sensors is the measurement of complex effects like sum parameters. The difficulties involved in analyzing the numerous substances that are present in wastewater samples make sum parameters an indispensable part of the wastewater monitoring systems. Additionally, sum parameters often allow a better evaluation of the status of the environment than the determination of the concentration of individual substances. Examples for complex parameters are the sum of biodegradable or bioavailable compounds and toxicity (BOD, ADOC). 

In this manner, a nearly universal and very nonselective detector is created that is a compromise between widespread response and high selectivity. For example, the photoionization detector (PID) can detect part-per-billion levels of benzene but cannot detect methane. Conversely, the flame ionization detector (FID) can detect part-per-billion levels of methane but does not detect chlorinated compounds like CCl very effectively. By combining the filament and electrochemical sensor, all of these chemicals can be detected but only at part-per-million levels and above. Because most chemical vapors have toxic exposure limits above 1 ppm (a few such as hydrazines have limits below 1 ppm), this sensitivity is adequate for the initial applications. Several cases of electrochemical sensors being used at the sub-part-per-million level have been reported (3, 16). The filament and electrochemical sensor form the basic gas sensor required for detecting a wide variety of chemicals in air, but with little or no selectivity. The next step is to use an array of such sensors in a variety of ways (modes) to obtain the information required to perform the qualitative analysis of an unknown airborne chemical. 

An area for analytical chemists to focus on is the development of methods and technology that will allow preventing and reducing the generation of hazardous substances in chemical processes. In order to be able to effect changes, we require reliable sensors, monitors, and analytical techniques to assess the hazards in process streams. When toxic substances (e.g., by-products and side reactions)... 

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