Proton recent research

More recent research provides reversible oxidation-reduction potential data (17). These allow the derivation of better stmcture-activity relationships in both photographic sensitization and other systems where electron-transfer sensitizers are important (see Dyes, sensitizing). Data for an extensive series of cyanine dyes are pubflshed, as obtained by second harmonic a-c voltammetry (17). A recent "quantitative stmcture-activity relationship" (QSAR) (34) shows that Brooker deviations for the heterocycHc nuclei (discussed above) can provide estimates of the oxidation potentials within 0.05 V. An oxidation potential plus a dye s absorption energy provide reduction potential estimates. Different regression equations were used for dyes with one-, three-, five-methine carbons in the chromophore. Also noted in Ref. 34 are previous correlations relating Brooker deviations for many heterocycHc nuclei to the piC (for protonation/decolorization) for carbocyanine dyes the piC is thus inversely related to oxidation potential values. 

Most of the recent research focuses on proton, lithium, sodium and potassium batteries. This is not only for the reasons discussed above. The availability of a large variety of electrodes also plays an important role. Furthermore, high voltages rather than high currents are favorable from a practical point of view. 

Recent research has suggested that short synthetic peptides containing different analogs of the first 19-23 amino acid residues of influenza hemaglutinin protein (HA) terminus may be attractive because of their pH-dependent lytic properties, with little activity at pH 7 but > 100-fold increase in transfection efficiency at pH 5. The lytic characteristics are revealed as the carboxyl groups of the aspartyl and glutamyl side chains are protonated, which allows the peptides to assume a a-helical conformation that can be inserted into the membrane bilayer. 

The key intermediate in the catalytic pathway is the supemucleophile cob(l)alamin, which attacks A -methyl-tetrahydrofolate, generating tetrahydrofolate and MeCbl. Then homocysteine (probably as its thiolate) attacks MeCbl, which yields methionine and regenerates cob(l)alamin (Scheme 2). The demethylation of A -methyltetrahydrofolate is not trivial, even for the supemucleophilic cob(l)alamin, and considerable efforts have been invested into understanding this reaction, dubbed improbable by Duilio Arigoni. The obvious mode of activation is by proton transfer to N-5 of A -methyl tetrahydrofolate, but as this is weakly basic (pAa 5.1) the nature of the proton source and mode of transfer has been difficult to pin down. Recent research from the Matthews group has shown how the reactivities of cob(I)alamin and methylcobalamin are modulated by the ligand trans to the lone pair of cob(l)alamin and methyl group of methylcobalamin (21). 

Sour taste detects acids, i.e., protons. Several different sour taste receptor candidates such as acid-sensing ion channels (ASICs) (57), hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) (58), and two pore domain potassium channels (K2PS) (59, 60) have been described in the past. In addition, recent research identified two members of the polycystic kidney disease (PKD) family of the transient receptor potential superfamily (TRP) as strong sour taste receptor candidates or as part thereof. Immunohistochemistry and in situ hybridization revealed the presence of the polycystic-kidney-disease-like ion channel PKD2L1 in subsets of taste receptor cells of mouse fungiform, vallate, and foliate papillae. These cells differ from... 

In recent research, the concept of simultaneous electron and proton transfer has been explored. In this process, directly coupled electron and proton transfer result in the formal transfer of a hydrogen atom (Figure 18, path C). In this pathway, two quantum events occur electron tunneling and proton tunneling [56. Whereas electron tunneling is a well-accepted phenomenon, proton tunneling is a far less commonly invoked property. Proton tunneling can be readily understood if we consider... 

The recently developed high-resolution solid-state NMR technique proton CRAMPS NMR has become a very useful research tool, corresponding to X-ray crystallography, and enabling the study of crystal structure polymorphs of amino acids. In this chapter, we first discuss a recent research example application to crystal structure analysis of polymorphic forms of some typical a-amino acids in order to test the power of H CRAMPS NMR, compared with C and N NMR methods. 

In recent research, a new evaluatimi method for the utilization under actual operating conditions was proposed as an effectiveness of platinum ( /pt) [18], based on the comparison of ORR mass activities for the MEA with those measured with the channel flow technique at the same temperature. The Efp value indicates the extent to which Pt particles exist in the CL in an optimal condition of binder coverage. A schematic depiction of the variation of PFSA film thickness with depth within the CL is shown in Fig. 6. In the case of t/pt, the concept of Pt utilization can be rationalized from Fig. 6, because the f/pt values are not affected by either proton conductance or the gas diffusion... 

Savinell RF (2012) Recent research of the PBI/PA system as a proton conductor in electrochemical systems. Presentation at Carisma 2012, Copenhagen, Denmark. http //www.hotmea.kemi.dtu.dk/ /media/ Centre/ENRGK HotMEA/carisma2012/ presentations posters/savinell carisma 2012.ashx... 

Abstract Protoberberine alkaloids and related compounds represent an important class of molecules and have attracted recent attention for their various pharmacological activities. This chapter deals with the physicochemical properties of several isoquinoline alkaloids (berberine, palmatine and coralyne) and many of their derivatives under various environmental conditions. The interaction of these compounds with polymorphic DNA structures (B-form, Z-form, H -form, protonated form, triple helical form and quadruplex form) and polymorphic RNA structures (A-form, protonated form, triple helical form and quadruplex form) reported by several research groups, employing various analytical techniques such as spectrophotometry, spectrofluorimetry, circular dichro-ism, NMR spectroscopy, viscometry as well as molecular modelling and thermodynamic analysis to elucidate their mode and mechanism of action for structure-activity relationships, are also presented. 

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