Critical for the initiation

LAP proteins prevent cell death through interactions between their BIR (baculoviral) IAP repeat domains and the proteases that are critical for the initiation and execution of apoptosis, caspase-3, caspase-7, and/or caspase-9 (23). X-chromosome... 

As mentioned earlier, a fiber fraction and a powder fraction of cotton cellulose were formed during milling the changes in crystallinity for these two fractions are different For the fiber fraction, the loss of crystallinity was critical for the initial 100 hrs of milling, as shown in Figure 4. The rate of change in crystallinity was then levelled off after 100 hrs of... 

Easy availability of ultrafast high intensity lasers has fuelled the dream of their use as molecular scissors to cleave selected bonds (1-3). Theoretical approaches to laser assisted control of chemical reactions have kept pace and demonstrated remarkable success (4,5) with experimental results (6-9) buttressing the theoretical claims. The different tablished theoretical approaches to control have been reviewed recently (10). While the focus of these theoretical approaches has been on field design, the photodissociation yield has also been found to be extremely sensitive to the initial vibrational state from which photolysis is induced and results for (11), HI (12,13), HCl (14) and HOD (2,3,15,16) reveal a crucial role for the initial state of the system in product selectivity and enhancement. This critical dependence on initial vibrational state indicates that a suitably optimized linear superposition of the field free vibrational states may be another route to selective control of photodissociation. 

Morton and Salatiello have deduced the ratio kpp/kp for radical polymerization of butadiene by applying the above described procedure, appropriately modified for the emulsion system they used. The primary molecular weight was controlled by a mercaptan acting as chain transfer agent, as in the experiments of Bardwell and Winkler cited above. Measurement of the mercaptan concentration over the course of the reaction provided the necessary information for calculating % at any stage of the process, and in particular at the critical conversion 6c for the initial appearance of gel. The velocity constant ratios which they obtained from their results through the use of Eq. 

From the results discussed above as well as from the literature data [5-10,12-14] it follows that an important role of O2 in the SCR process is to convert NO into NOj. The latter then initiates methane oxidation into CO, and is itself reduced into NO and N2. Both NO, and O2 may participate in CH4 oxidation (Fig. 1B) and the ratio between the rates of these competitive oxidation reactions will be critical for the selectivity of the SCR process. Hence, the absolute rates of CH4 oxidation by Oj were compared with those occurring in the SCR process. The rates of these reactions were determined under different reaction conditions (using the... 

Anionic polymerization techniques were also critical for the synthesis of a model cyclic triblock terpolymer [cyclic(S-fo-I-fr-MMA)] [196]. The linear cctw-amino acid precursor S-fr-I-fr-MMA was synthesized by the sequential anionic polymerization of St, I and MMA with 2,2,5,5-tetramethyl-l-(3-lithiopropyl)-l-aza-2,5-disilacyclopentane as the initiator and amine generator, and 4-bromo-l,l,l-trimethoxybutane as a terminator and carboxylic acid generator. Characterization studies of the intermediate materials as well as of the final cyclic terpolymer revealed high molecular and compositional homogeneity. Additional proof for the formation of the cyclic structure was provided by the lower intrinsic viscosity found for the cyclic terpolymer compared to that of the precursor. 

All of these make the formation of the first protocell rather critical. There is also the general problem of membrane transport and how molecules might form within the protocell. The simplest postulated mechanism for the initial inclusion of molecules in protcells is that of encapsulation. 

The success of the present method depends critically on the initial presence of an alcohol to trap the intermediate phosphonium species.12 If the alcohol is added last, the R3P—CX4 reaction described above (an exothermic process for the more nucleophilic phosphines) may go to completion, in which case little or no alkyl halide is formed.13 Since the reaction displays several characteristics of an SN2 process, it is thought to proceed by the pathway illustrated ... 

Questions have been raised about this approach to calculating detonation limits, and some believe that the general agreement between experiments and the theory as shown in Table 5.6 is fortuitous. One of the criticisms is that a given Mach number specifies a particular temperature and a pressure behind the shock. The expression representing the explosive condition also specifies a particular pressure and temperature. It is unlikely that there would be a direct correspondence of the two conditions from the different shock and explosion relationships. Equation (5.49) must give a unique result for the initial conditions because of the manner in which it was developed. 

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