Evidence investigation types

So far, there have been published only a few papers devoted to experimental investigation of multiplicity and oscillatory activity of a single catalyst particle. Observations of multiple steady states and/or oscillations for a single catalyst particle are reported in Table IV. Evidently three types of strong exothermic reactions have been investigated ... 

The main elements of DNA and linguistics analysis necessitate a new bridging theory of population cmcibles. The elements of this theory have been in existence since George Todaro and his team at the US National Cancer Institute began investigating Type C vims antibodies twenty years ago. Nowadays, evidence is rapidly accumulating to support his surprising conclusions. 

Remember, evidence is anything that is real, has substance, and helps to estabHsh the facts of an accident investigation. Types of physical evidence you might want to re-examine include the following ... 

The versatility of this reaction is extended to a variety of aldehydes. The bisphenol derived from 2,6-di-/ f2 -butylphenol and furfural, (25) where R = furfuryl (13), is also used as an antioxidant. The utility of the 3,5-di-/ f2 -butyl-4-hydroxyben2yl moiety is evident in stabili2ets of all types (14), and its effectiveness has spurred investigations of derivatives of hindered alkylphenols to achieve better stahi1i2ing quaUties. Another example is the Michael addition of 2,6-di-/ f2 -butyl phenol to methyl acrylate. This reaction is carried out under basic conditions and yields methyl... 

From the literature it is evident that air recirculation has been used and is used for many different types of ventilated areas. For this reason there have been some large investigations into the advantages and disadvantages of using air re-... 

These results indicate that in these new ester mydriatics, the structural factors, which influence the development of this type of pharmacological action are similar to those made evident by the chemical investigations of Jowett and Pyman and the pharmacological work of Marshall, Dale, Laidlaw and Cushny on the tropeines. The nature of the basic component is obviously important since mydriasis is produced by simple bases such as ephedrine. As regards the nature of the esterifying acid, Jowett and Pyman drew the following conclusions — ... 

Methods of the first type have been used for both qualitative and quantitative investigation. An important limitation is that the rates of interconversion of the tautomeric forms must be small as compared with those of the test reaction (s). The method is further complicated since the test reactions are sometimes complex and it is difficult to be certain that only one tautomer is reacting. An even more fundamental objection is that much chemical evidence is based on incorrect reaction mechanisms. Thus, the formation of condensation products (30) with aldehydes has repeatedly been quoted as evidence for structures of type 31 and against type 32,. whereas if 31 does react with an aldehyde it must either first tautomerize to 32 or ionize to 33. 

Isoxazol-5-ones can exist in three different types of structures, cf. 45- 7 (R = H). Early investigators assigned structures to these compounds on the basis of unreliable chemical evidence thus the NH structure 47 was favored because the silver salt of 3-phenyl-isoxazol-5-one reacts with methyl iodide to give a product which was incorrectly (see reference 44) formulated as the iV-incthyl derivatives (cf. also reference 46). Bromine titration data led to assignment of an incorrect structure to 3,4-diphcnylisoxazol-5-one cf. article I (Volume 1), Section II,A. Comparison of the dipole moments of 3-phenyIisoxazol-5-one with those of the methyl derivatives 45 (R = Me) and 46... 

As early as 1895, Knorr realized that three types of derivatives could be formed for this type of compound, corresponding to the three tautomeric structures. Other early investigators assigned an 0X0 structure to these compounds on the basis of tenuous chemical evidence, while still others discussed the tautomerism without reaching any definite conclusions. ... 

Optically active imidazol-4-one-5-acetic acid has been prepared by Kny and Witkop, and therefore it must exist as 108 or 109 rather than as 110. Similarly, Grob and Ankli -- have presented ultraviolet and infrared spectral evidence for compounds of type 111 existing in the 0X0 form. These same investigators considered structure 112 rather than 113 to represent the predominant tautomeric form of the O-methyl derivatives how ever, it would be most surprising if this conclusion were correct. 

Evidence that the actual methylation of the anion can be divided into SnI, Eq. (3), and Sx2 types, Eq, (4), is provided by a whole series of investigations. " The terms S l and 8 2 must be taken to mean reactions with, respectively less or greater nucleophilic participation of the anion in the transition state. The importance of oriented ion pairs" in the solvents of low polarity frequently used in reactions involving diazomethanc, e.g., the ions formed by a diazoalkane and benzoic acid in ether, should be emphasized. The expression oriented ion pair means that, because of insufficient solvation, the ions are not individually solvated but exist as ion pairs within a solvent cage. The orientation within the ion pair is defined electrostatically, and this orientation fixes the path for the productdetermining step. Several indications (cf, foo otes 22-24) in the literature indicate the occurrence of carbonium ions and oriented ion pairs in Broensted-type equilibria of the type of Eq. (2). 

Since the quantum yield of the Norrish type I reaction is generally low, it has been assumed that the initial homolytic cleavage is a reversible process. Evidence came from an investigation by Barltrop et al. which has shown that erythro-2,3-dimethylcyclohexanone 12 isomerizes to t/zreo-2,3-dimethylcyclohexanone 13 upon irradiation ... 

The most important conclusion of the foregoing investigations is evidence of the presence of two types of structures in samples crystallized from the oriented melt FCC that amount to 85-90% of the total mass of the sample and ECC with the melting temperatures exceeding by 5-6 K for polyethylene and 15-20 K for polypropylene the... 

The theory described in Sect. 3.5.1 has received most justification from its agreement with observations. Ultimately this must be the case for any successful theory. However, the consequences of any assumptions made should be well understood as several independent and adjustable parameters can make an unrealistic approach appear reasonable. In recent years, some of the experimental features not well represented by this theory have been attributed to unrealistic approximations which would invalidate the basis of the theory. Hence we give a careful step-by-step critique, and emphasize the consequences of alternative assumptions. In Sect. 3.5.3 when we investigate the experimental evidence, we should be better able to establish whether various types of behaviour can be accommodated within the theory. 

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