Transition sequences

Activation of bayerite [20257-20-9] and nordstrandite [13840-05-6] quaUtatively follows the pattern shown in Figure 4, but the transition sequence is eta-theta-alpha. The stmctures of these transition phases are somewhat different from those obtained from gibbsite, reflecting the differences in crystal stmcture of the hydroxides (16). 

In 1938 I concluded (2) from the consideration of the values of their saturation ferromagnetic moments that the elements of the first transition sequence from Cr to Ni have the constant metallic valence 5.78, later revised 8) to 6. Despite their lack of ferromagnetism, I assumed (9) in 1947 that their heavier congeners Mo to Pd and W to... 

Fig. 4a,b. The effect of substitution of an alkoxy tail for an alkyl tail in cyanobiphenyls a transition sequence is K kf N b transition sequence is K N /... 

Little is known of how the biosynthetic metabolon is assembled, what mechanisms control the membrane-specific targeting, and how the conversions to apocarotenoids occur. Yet the current approach to drive import of bacterial or plant genes is to use transit sequences of a stromal protein that may limit the effectiveness of the transgene. In addition, for specific applications of controlling carotenoid composition, we need to better understand the interactions of the various enzymes,... 

Figure 6.6 Transient hole current in a-As2Se3 (1) and (2) annealed sample, (3) and (4) photodarkened sample. The area between (1) and (2) and (3) and (4) indicates space charge accumulation during a 10-transit sequence with repetition frequency lOHz. d = 3.4pm,...

Bulk-space-charge creation is shown in Fig. 6.6 in the areas between curves 1 and 2 and 3 and 4. The estimated amount of charge accumulated by deep traps during a 10-transit sequence increases 1.3-2 times at photodarkening and approaches about... 

The other halides form a transitional sequence between these extremes, with the properties fairly smoothly changing in the order of increasing softness Cl- < Br < I. ... 

Thoughtful Transition/Sequencing-Logical/Effective Pacing Controlled/Flows Smoothly... 

The smectic state, apart from exhibiting a rich variety of modifications, is also thermodynamically ordered. Thus, there is a well-defined sequence of phases formed on cooling from the isotropic liquid. For instance, the following transition sequence would be observed for a ferrocene liquid crystal exhibiting enantiotropic smectic C, smectic A and nematic phases ... 

Crytal chemitry. Solid solutions of lead phosphate compounds with structures like that of palmierite ((K,Na)2Pb(S04)2) exhibit transition sequences that are well modeled by Landau-Ginzburg excess free energy expressions. Systems that have been especially heavily studied include Pb3(Pi (As (04)2 (Toledano et al. 1975, Torres 1975, Bismayer and Salje 1981, Bismayer et al. 1982, 1986 Salje and Wruck 1983) and (Pbi jcA c)3(P04)2, where A = Sr or Ba (Bismayer et al. 1994, 1995). The phase diagram for the phosphate-arsenate join is not completely mapped, but Bismayer and collaborators have identified a series of transitions for the P-rich and the As-rich fields. The structure consists of two sheets of isolated (P,As)04-tetrahedra with vertices pointing towards each other and a sheet of Pb atoms in the plane of the apical oxygen atoms. Layers of Pb atoms lie between these tetrahedral sheets (Fig. 18) (Viswanathan and Miehe 1978). 

The critical temperatures for the monoclinic to triclinic transition decrease with increasing Sr content (Fig. 28). As with the transition sequence, the room-temperature critical composition xsr varies with the degree of Al-Si order. Experimental data (Bruno... 

Riesner D, Steger G, Zimmat R, Owens RA, Wagenhofer M, Hillen W, et al. Temperature-gradient gel electrophoresis of nucleic acids analysis of conformational transitions, sequence variations, and protein-nucleic, acid interactions. Electrophoresis 1989 10 377-89. 

Herein, we expand on the discussion of our recently observed isothermal amorphous-amorphous-amorphous transition sequence. We achieved to compress LDA in an isothermal, dilatometric experiment at 125 K in a stepwise fashion via HDA to VHDA. However, we can not distinguish if this stepwise process is a kinetically controlled continuous process or if both steps are true phase transitions (of first or higher order). We want to emphasize that the main focus here is to investigate transitions between different amorphous states at elevated pressures rather than the annealing effects observed at 1 bar. The vast majority of computational studies shows qualitatively similar features in the metastable phase diagram of amorphous water (cf. e.g. Fig.l in ref. 39) at elevated pressures the thermodynamic equilibrium line between HDA and LDA can be reversibly crossed, whereas by heating at 1 bar the spinodal is irreversibly crossed. These two fundamentally different mechanisms need to be scrutinized separately. 

Fig. 6 (B) shows a recording of neutral-red absorbance changes in chloroplasts, with the initial population present in the Si-state, in response to a flash train. The chloroplasts also contained the inhibitor DNP-INT (dinitrorphenolether of iodonitrotoluol) to suppress plastohydroquinone oxidation and the attendant proton release. The recording is obtained by averaging the responses of 100 fresh chloroplast samples. With a 200-/ -per-channel time resolution, the rapid rise is only partially resolved. A plot of the relative yield ofthe released protons in Fig. 6 (B) actually shows a proton-release pattern of [0,1,2,1 ] for the transition sequence [Si->S2->S3->(S4)->So->S,]. Since the initial, dark-adapted state was 100% in the S, state, the proton release pattern in the [So->S,->S2->S3->(S4)->So] transition is thus [1,0,1,2].

Structural similarities can be seen, however, when the hydropathy profiles of the tobacco and Arabidopsis ALS transit peptides are compared (not shown). This suggests that a functional transit sequence depends more on secondary or higher order structural constraints than on primary sequence information. The in vitro uptake system described above can be used to further investigate the transit peptide domain. 

EPSPS specific activites of calli transformed with EPSPS genes with and without chloroplast transit sequences... 

Stark and Zeeman polarization quantum beats are discussed in Section 6.5.3. An external electric or magnetic field destroys the isotropy of space. As a result, the amplitudes for two transition sequences J", M" — J, M = M" 1 —> J ", M" interfere, and the intensity of X or Y (but not Z) polarized fluorescence is modulated at (Fj M =M"+i — Ejim =M"-i)/h. However, it is not necessary to destroy the isotropy of space in order to observe polarization quantum beats. 

Merriman RJ, Roberts B, Peacor DR (1990) A transmission electron mocroscope study of white mica crystallite size distribution in a mudstone to slate transitional sequence. North Wales, U.K. Contrib Mineral Petrol 106 27-40... 

Phase Transitions in Lipid Assemblies. The rich polymorphism of amphiphilic systems, of which the multilamellar and the Hn phases are only two structures, was made evident from the seminal work of Luzzati and co-workers. Since that early work, an immense variety of water-induced phase transitions have been observed and rationalized in terms of an apparently systematic connection between water content and polar group molecular area. Therefore, the recent observation of a double transition—Hn to lamellar back to Hn—from continual hydration of dioleoylphosphatidyl-ethanolamine (40) was a surprise. Furthermore, an estimate of the cost of uncurling the monolayer in the formation of bilayers based on the previously described bending modulus far exceeds the osmotic work that actually produced the transition. Although this transition sequence can successfully be accounted for by simple thermodynamical principles, it, in fact, contains many geometry-dependent free energy contributions that we simply do not yet understand (41). 

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