Trigger linkage

Aa interesting variation of this emphasis upon the trigger linkage was offered by Kohno et al [47-49], who noted that the N-NO, distances in a group of seven nitramines (including RDX and the polymorphs of HMX) are shorter in the crystal than in the gas phase, by 0.05 - 0.08 A. This does not occur with the C-N and N-O bonds. They suggested that this compression introduces destabilizing strain into the crystal, and were able... 

It is believed that C-NOj homolysis is the first or one of the first steps in TATB initiation [12]. This is consistent with the idea of a trigger linkage. However the key early decomposition reactions appear to produce furazans and furoxans, e.g. 10 and 11 [12,13,18,65,77,82] ... 

If this has a AV of -20 cc/mole one can very crudely estimate aci ion concentrations of 10" to 10 M at pressure conditions adequate to initiate homogeneous nitromethane. The aci ion is a very reactive species. It is known to be a good nucleophile, a precursor to fulminic acid, and a facile electron transfer agent. If these very small amounts of an intermediate are kinetically competent to bring about the violent exothermic decomposition of nitromethane it must indeed be very reactive. This is the basis for the arguments related to the amine sensitization of nitromethane [39]. Does one then view the C-H bond in nitromethane as the trigger linkage ... 

A third example is the dramatic difference in the impact sensitivity of 1-picryl-l,2,3-triazole and 2-picryl-1,2,3-triazole, as mentioned earlier in this article. An extensive structural and theoretical analyses [27] has been carried out on these isomers. It was concluded that the 1-picryl-l,2,3-triazole isomer loses nitrogen by a low activation energy, exothermic, process. This drives the propagation of the hot spot. In this case the N2 loss is certainly a "trigger linkage". 

We have shown a relationship between impact and shock sensitivity and illustrated how a sensitivity index based on oxygen balance can be used to estimate sensitivity in closely related series of molecules. It is shown that the critical temperature of an explosive calculated by the Frank-Kamenetskii equation correlates fairly well with the shock sensitivity of the material. This supports the idea that the shock or impact initiation of an explosive is primarily a thermal event and not dominated by pressure driven chemistry. The concept of the "trigger linkage" in explosives is discussed and it is pointed out that insensitive explosives will require early chemistry that is thermochemically neutral or endothermic and leads to the build-up of later strongly exothermic chemistry. 

The train of events from sender to receiver is seen as following the sequence C + L = L (transmission) => L + C => L-VNOR. At the last step, the G-protein linkage induces the second messenger cascade whose amplification triggers the appropriate ion-channel (Chaps. 5 and 7). The role of the carrier(s) at either end of the transmission sequence is gradually emerging, but without any consensus on their exact contribution, or even on whether they are a crucial component for information transfer (Tegoni et al., 2000). 

Fig. 2 Masked endosomolytic agents for pH-triggered endosomal escape. The polymers designed by Meyer et al. [69] (a) and Rozema et al. [71] (b) contain endosomolytic compounds whose lytic potential is activated by endosomal cleavage of masking groups coupled by acid-sensitive linkages. Furthermore, disulfide bonds are embedded which release the nucleic acid after endosomal escape by cleavage in the reducing cytosolic environment...

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