Nuclear agents detection

One of the major issues in national security is the detection of potentially hazardous materials before they do harm to people or property. Thus, the sensing of chemical, biological, and nuclear agents quickly, specifically, and at a distance is of primary importance. Currently available detectors based on semiconductors have a wide range of applicability high-energy and low-energy ends of the spectrum are especially important. 

Biological agents require no precursors for development, unlike chemical and nuclear agents, and a covert program is much more difficult to detect. 

Based on the history of terrorist attacks, which have mostly involved hijacking and bombing of aircraft, current threat-detection measures have concentrated on detecting weapons or explosives. In the future, terrorist attacks could also involve the use of toxic chemicals, chemical and biological warfare agents, or even radiological and nuclear materials.1 2... 

Endocrine disruptors apparently affect all nuclear receptors. Thus, a notable increment in impotence, alterations of the libido and of oligospermia in workers exposed to pesticides has been described. These alterations are due to the action of some compounds with estrogen-mimetic action and to their interaction with the androgen receptor. Additionally, alterations of thyroid function have been detected in rats exposed to dioxin and other toxic agents,... 

Detection The determination of the presence of a chemical agent, biological agent, or nuclear substance. 

After damage or infection, monocytes and KCs in the area detect the damaged cells or infectious agent and respond with release of primary mediators such as TNFa, IL-1 and some IL-6. These cytokines activate the surrounding cells, that respond with a secondary, amplified release of cytokines. This second wave includes large amounts of IL-6, which induce the synthesis of acute phase proteins in hepatocytes and chemoattractants such as IL-8 and MCP-1. These events will then lead to the typical inflammatory reactions. Both IL-1 and TNFa activate the central regulatory protein of many reactions involved in immunity and inflammation, nuclear factor kappa B (NFkB). These cytokines cause dissociation of NFkB from its inhibitor IkB, which makes translocation of NFkB to the nucleus possible. In the nucleus active NFkB induces the transcription of the second wave cytokines (see also Chapter 7 for the molecular mechanisms of cytokine-mediated cell activation). 

The three-pulse electron spin-echo envelope modulation (ESEEM) technique is particularly sensitive for detecting hyperfine couplings to nuclei with a weak nuclear moment, such as 14N. It has been used to probe the coordination state of nickel in two hydrogenases from M. tkermoautotrophicum, strain AH (56). One of these enzymes contains FAD and catalyzes the reduction of F420 (7,8-dimethyl-8-hydroxy-5-deazaflavin), while the other contains no FAD and has so far only been shown to reduce artificial redox agents such as methyl viologen. 

Human erythrocytes, for blood pool imaging, red blood cell mass determination, detection of vascular malformations and nuclear cardiology. Heat-damaged red blood cells also yield an excellent agent for spleen imaging15,241. 

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