Questions about Mechanisms

In conclusion, despite the exciting low-frequency US results obtained, there remain important questions about mechanism, local skin effects and tolerability, reversibility, and ultimate practicability. These issues must be addressed before sonophoresis can move from research to development mode. 

The identification of mixing as an important process both in the mantle and between the crust and mantle inevitably leads to more profound questions about mechanisms of mixing and how they relate to major plate tectonic processes. This takes us into the field of geodynamics — a topic briefly discussed at the end of this chapter. 

L. de Broglie, Some questions about mechanics and thermodynamics in the classical and relativistic frames, [Diverses questions de mecanique et de thermodynamique classiques et relativistes (French)], G. Lochak, ed.. Lecture Notes in Physics M 32, Springer-Verlag, Berlin, 1995. 

An important question about the mechanism of acid catalyzed esterification concerns the origin of the alkoxy oxygen For example does the methoxy oxygen m methyl benzoate come from methanol or is it derived from benzoic acid s... 

An alternative chain-terminating decomposition of the tetroxide, known as the Russell mechanism (29), can occur when there is at least one hydrogen atom in an alpha position the products are a ketone, an alcohol and oxygen (eq. 15). This mechanism is troubling on theoretical grounds (1). Questions about its vaUdity remain (30), but it has received some recent support (31). 

In many ways, the title of this section is the central question that those with a predilection for toying with fundamental issues eventually find themselves asking. It is also a question that (not unlike the problem of formulating a legitimate - or even an allowable - question about what is really going on in quantum mechanics), must be asked correctly. It is not enough merely to rusk the que.stion in its simplest form. We must first of all be sure of what we are asking. 

One of the fundamental questions about the mechanism is whether the radical is really free in the sense of diffusing from the metal surface.7 For alkyl halides, there is considerable evidence that the radicals behave similarly to alkyl free radicals.8 One test for the involvement of radical intermediates is to determine whether cyclization occurs in the 6-hexenyl system, where radical cyclization is rapid (see Part A, Section 12.2.2). 

Simple tertiary carbocations represent a benchmark against which to compare the reactivity of other a-methyl carbocations. Therefore, it is necessary to deal with complex questions about the mechanism for substitution and elimination reactions at tertiary aliphatic carbon in order to evaluate the rate constant... 

Despite the importance of the drug, many questions about the mechanism of cispiatin activation, and its binding to DNA, still remain unresolved. Activation of cispiatin is believed to be a two-step process ... 

The continual development and evolution of novel and powerful technologies has allowed scientists to answer increasingly complex questions about the basic mechanisms underlying cellular homeostasis for the benefit of human health. Our understanding of how cells proliferate, thrive, adapt, and die in response to numerous environmental... 

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