Sensitization desensitization

Sensitizers as well as desensitizers form a reversal oxidoreduction system with silver halides, according to both pH and pAg of the photographic emulsion. But besides the specific influence of the emulsion, the efficiency of a sensitizing dye depends on many other factors such as its adsorption, its spectral absorption, the energetic transfer yield, the dye aggregate to the silver halide, and finally on its desensitizing property in... 

C. Boyars, "Sensitivity and Desensitization of Nitroglycerin," ia Proceedings of 2nd Symposium on Chemical Problems Connected with the Stability of... 

Gun Propellents. Low sensitivity gun propeUants, often referred to as LOVA (low vulnerabUity ammunition), use RDX or HMX as the principal energy components, and desensitizing binders such as ceUulose acetate butyrate or thermoplastic elastomers (TPE) including poly acetal—polyurethane block copolymers, polystyrene—polyacrjiate copolymers, and glycidyl azide polymers (GAP) to provide the required mechanical... 

According to the electron-transfer mechanism of spectral sensitization (92,93), the transfer of an electron from the excited sensitizer molecule to the silver haHde and the injection of photoelectrons into the conduction band ate the primary processes. Thus, the lowest vacant level of the sensitizer dye is situated higher than the bottom of the conduction band. The regeneration of the sensitizer is possible by reactions of the positive hole to form radical dications (94). If the highest filled level of the dye is situated below the top of the valence band, desensitization occurs because of hole production. 

The opposite phenomenon, a decrease of sensitivity, is known as desensitization. The main reasons for densensitization ate the results of relative electron level positions as weU as the secondary processes of the photoelectrons, for example (97),... 

A good sensitizing dye does not interfere with other system properties. Sensitizing dyes can sometimes influence the intrinsic response of a chemically sensitized emulsion, leading to desensitization or additional sensitization. The dye can also interfere with development rate, increase or decrease unwanted fog density, and remain as unwanted stain in the film after processing. The dye should have adequate solubihty for addition to the emulsion, but should not wander between layers in the final coating. 

Tachyphyllaxis, the progressive reduction in response due to repeated agonist stimulation (see Desensitization and Fade). The maximal response to the agonist is reduced in tachyphyllaxis (whereas the sensitivity is reduced with tolerance). 

P.A." Explosives. A variety of expl blends, patented by the firm of Bombrini-Parodi-Delfmo of Rome, consisting of PETN desensitized with pentaerythritol acetate. These expls can be cast below 100°, are less sensitive to shock than PETN, but more sensitive than TNT. Although they are less powerful and brisant than PETN, they are more so than TNT. Their stability is less than that of TNT. Their advantage in comparison with RDX formulations lies in the uniformity of the blend... 

The use of paraffin in the expl industry is extensive, not only as a moisture protecting agent, but as a desensitizer. Paraffin can be incorporated either directly with ingredients of expl compns (at a temp above its mp), or one or more ingredients can be coated separately with molten paraffin and then mixed. When hygroscopic substances, such as AN, Na nitrate, etc, are coated in such a manner, they are rendered less hygroscopic, and, when the same procedure is applied to sensitive compds or expls (K chlorate, RDX, PETN, etc) their sensitivity can be markedly reduced... 

If an expl is to be used for APS (armorpiercing shell) application, the same requirements as above are pertinent, except that the impact sensitivity should be veiy low (Explosive D, TNT desensitized with wax, etc, would be suitable)... 

In general, treatment of the asthma underlying NSAlDs sensitivity should follow standard asthma guidelines. This type of asthma is often severe and frequently high doses of inhaled corticosteroids and daily doses of oral corticosteroids are necessary. A special treatment option is a chronic desensitization to aspirin [8]. Desensitization and aspirin maintenance is routinely used in some centers for treatment of chronic rhinusinusitis with nasal polyposis. It is the only available procedure which allows AIA patients with ischemic heart disease to use aspirin. During the state of desensitization to aspirin, not only aspirin but almost all strong NSAIDs are tolerated, so desensitization and NSAID maintenance could be used for treatment of rheumatic disease or chronic pain syndromes. 

At present, two conceptually different (but not mutually exclusive) therapeutic strategies are being pursued in the vanilloid field one is to use optimized TRPVl agonists to desensitize (in practice, defunctionalize) capsaicin-sensitive nerves [1, 21] and the other is to employ small molecule antagonists for the pharmacological blockade of TRPVl [7, 8]. The first approach is time-proven, but is riddled by known side-effects such as pain [1], as well as emerging concerns such as impaired control of cancerous growth [22]. 

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