The First Evidence

Detailed x-ray diffraction studies on polar liquid crystals have demonstrated tire existence of multiple smectic A and smectic C phases [M, 15 and 16]. The first evidence for a smectic A-smectic A phase transition was provided by tire optical microscopy observations of Sigaud etal [17] on binary mixtures of two smectogens. Different stmctures exist due to tire competing effects of dipolar interactions (which can lead to alternating head-tail or interdigitated stmctures) and steric effects (which lead to a layer period equal to tire molecular lengtli). These... 

Gr. helios, the sun). Janssen obtained the first evidence of helium during the solar eclipse of 1868 when he detected a new line in the solar spectrum. Lockyer and Frankland suggested the name helium for the new element. In 1895 Ramsay discovered helium in the uranium mineral clevite while it was independently discovered in cleveite by the Swedish chemists Cleve and Langlet at about the same time. Rutherford and Royds in 1907 demonstrated that alpha particles are helium nuclei. 

Tackifying resins enhance the adhesion of non-polar elastomers by improving wettability, increasing polarity and altering the viscoelastic properties. Dahlquist [31 ] established the first evidence of the modification of the viscoelastic properties of an elastomer by adding resins, and demonstrated that the performance of pressure-sensitive adhesives was related to the creep compliance. Later, Aubrey and Sherriff [32] demonstrated that a relationship between peel strength and viscoelasticity in natural rubber-low molecular resins blends existed. Class and Chu [33] used the dynamic mechanical measurements to demonstrate that compatible resins with an elastomer produced a decrease in the elastic modulus at room temperature and an increase in the tan <5 peak (which indicated the glass transition temperature of the resin-elastomer blend). Resins which are incompatible with an elastomer caused an increase in the elastic modulus at room temperature and showed two distinct maxima in the tan <5 curve. 

The first evidence for thionitrosoarenes 4-XC6H4N=S (X = H, Cl, Br) was gleaned from trapping experiments in which the Diels-Alder... 

The first evidence for an unsymmetrical structure for the benzo-furoxan molecule and for the tautomerism of Eq. (3) was provided in 1961 by several groups of workers," using proton resonance... 

Water, the other source of kinetic energy used in antiquity, saw wider application to machineiy than did wind. The first evidence of the use of waterpower comes from the first century B.C.E., simultaneously in both China and the Mediterranean region. In China the preferred method of tapping the power of falling water was the horizontal water wheel, named after the plane of rotation of the wheel. Around the Mediterranean, the preferred form was the vertical... 

The terms hot corrosion or dry corrosion are normally taken to apply to the reactions taking place between metals and gases at temperatures above 100 C i.e. temperatures at which the presence of liquid water is unusual. The obvious cases of wet corrosion at temperatures above 100 C, i.e. in pressurised boilers or autoclaves, are not considered here. In practice, of course, common metals and alloys used at temperatures above normal do not suffer appreciable attack in the atmosphere until the temperature is considerably above 100 C. Thus iron and low-alloy steels form only the thinnest of interference oxide films at about 200 C, copper shows the first evidence of tarnishing at about 180 C, and while aluminium forms a thin oxide film at room temperature, the rate of growth is extremely slow even near the melting point. 

Then let us examine the rate relaxation time constant x, defined as the time required for the rate increase Ar to reach 63% of its steady state value. It is comparable, and this is a general observation, with the parameter 2FNq/I, (Fig. 4.13). This is the time required to form a monolayer of oxygen on a surface with Nq sites when oxygen is supplied in the form of 02 This observation provided the first evidence that NEMCA is due to an electrochemically controlled migration of ionic species from the solid electrolyte onto the catalyst surface,1,4,49 as proven in detail in Chapter 5 (section 5.2), where the same transient is viewed through the use of surface sensitive techniques. 

The isotope effects shown by Figures 1 and 8 demonstrate the transition from the stripping or pick-up mechanism to the complex model for different chemical reactions. As far as we know this is the first evidence for such a transition. It may be emphasized again that this transition should also be detected in the velocity spectra. Therefore, it would be desirable to construct apparatuses which allow one to measure velocity spectra at ion energies of about 1 e.v. 

In the laminar region the rms of streamwise velocity fluctuations was expected to be zero (Sharp et al. 2001). Figure 3.10 shows that the first evidence of transition, in the form of an abrupt increase in the rms, occurs at 1,800 < Re < 2,200, in full agreement with the flow resistance data. There was no evidence of transition below these values. Thus, the behavior of the flow in micro-tubes, at least down to a 50 pm diameter, shows no perceptible differences with the macro-scale flow. 

The first evidence of an anionic Diels Alder reaction was given by Rickborn [25a]. The reaction of anthrone with N-methylmaleimide in CHCI3 or THE occurs with low yield [26] (Equation 1.10), while in DMF or in the presence of catalytic amounts of amine (EtsN, Py) the reaction is completed in a few minutes [25]. 

Yet further oxidation removes at least one more electron from each P cluster with an +90 mV to yield a protein oxidized by a total of at least eight electrons and with EPR signals from mixed spin states of S = I and S = I (42, 47). The combined integrations of these signals demonstrated that their intensity was equivalent to that of the FeMoco EPR signals in the same preparations. This provided the first evidence (47) that MoFe proteins contained equivalent numbers of FeMoco centers and P clusters and that P clusters contained 8 Fe atoms. Previously it had been considered that the P clusters were fully reduced Fe4S4 clusters and thus that there were two P clusters for every FeMoco center per molecule. 

The chronology of the most remarkable contributions to combustion in the early stages of its development is as follows. In 1815, Sir Humphry Davy developed the miner s safety lamp. In 1826, Michael Faraday gave a series of lectures and wrote The Chemical History of Candle. In 1855, Robert Bunsen developed his premixed gas burner and measured flame temperatures and flame speed. Francois-Ernest Mallard and Emile Le Chatelier studied flame propagation and proposed the first flame structure theory in 1883. At the same time, the first evidence of detonation was discovered in 1879-1881 by Marcellin Berthelot and Paul Vieille this was immediately confirmed in 1881 by Mallard and Le Chatelier. In 1899-1905, David Chapman and Emile Jouguet developed the theory of deflagration and detonation and calculated the speed of detonation. In 1900, Paul Vieille provided the physical explanation of detonation... 

Crystallographic study of 2,5-DSP and poly-2,5-DSP demonstrated that the polymerization proceeded with retention of the space group (Pbca) of the starting 2,5-DSP crystal (Sasada et al., 1971 Nakanishi et al., 1972a). The result was the first evidence of an organic reaction which proceeded in the crystal lattice. 

Table 2 (Nakanishi et al., 1977). These results represent the first evidence that these reactions occur in the crystal lattice. Similar results and discussions have been introduced in other literature (Nakanishi et al., 1980 cf. Nakanishi et al., 1972a, 1977).

It is already evident that the turnover rate of a transmitter is only a crude measure of its release rate. Further limitations are that there is appreciable intraneuronal metabolism of some neurotransmitters notably, the monoamines. In such cases, turnover will overestimate release rate. Another problem, again affecting monoamines, is that some of the released neurotransmitter is taken back into the nerve terminals and recycled. This leads to an underestimate of release rate. Despite these drawbacks, studies of turnover rates uncovered some important features of transmitter release. In particular, they provided the first evidence for distinct functional pools of monoamines, acetylcholine and possibly other neurotransmitters a release pool, which could be rapidly mobilised for release, and a storage or reserve pool which had a slower turnover rate. 

Influence of substrates and inhibitors on reactivity towards group-specific reagents The first evidence suggesting the involvement of a conformational change in the... 

The Jamieson paper reports the results of a number of studies, some successful, others not. Failures can be ascribed to the difficulties encountered in log P control. The first evident trouble concerns the choice of the lipophilicity descriptor many prefer log P, but this choice is questionable as has been outlined by Lombardo (see Chapter 16). Secondly, variations in lipophilicity profile influence not only hERG activity, but also target selectivity and also ADMET properties. Lipophilicity is a bulk property and its modification can involve different moieties of the molecules. Once the chemical modulation has been designed, but before moving to the bench, the research group should predict the consequences of this change on each step of the drug s action, but unfortunately this is not always done. 

The first evidence for the formation of silenes came from the thermolysis of silacyclobutanes, which resulted in a retro-[2+2] process leading to the silene Me2Si=CH2 and ethylene1 ... 

The first evidence for a phosphasilene was reported in 1979.19 Thermolysis of 1,2-phosphasiletane 1 at 100°C gave the transient silylidenephos-phane Me2Si=PPh 2, which undergoes head-to-tail [2 + 21-cyclodimerization, as well as an insertion reaction into the Si—P bond in 1, leading to 3 and 4 (Scheme 1). 

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