The controlled growth of SnO2 nanoparticles for gas sensor applications is reported by these authors. Nb2O5 additive is used to control nucleation and growth of the SnO2 (see Figure), which is synthesized by the polymeric precursor method. Preliminary gas sensing measurements are performed and it is demonstrated that the response time of the Nb2O5‐doped SnO2 is faster than that of the undoped material.

Krokinobacter eikastus rhodopsin 2 (KR2) is a pentameric, light-driven ion pump, which selectively transports sodium or protons. The mechanism of ion selectivity and transfer is unknown. By using conventional as well as dynamic nuclear polarization (DNP)-enhanced solid-state NMR, we were able to analyse the retinal polyene chain between positions C10 and C15 as well as the Schiff base nitrogen in the KR2 resting state. In addition, 50% of the KR2 C andN resonances could be assigned by multidimensional high-field solid-state NMR experiments. Assigned residues include part of the NDQ motif as well as sodium binding sites. Based on these data, the structural effects of the H30A mutation, which seems to shift the ion selectivity of KR2 primarily to Na, could be analysed. Our data show that it causes long-range effects within the retinal binding pocket and at the extracellular Na binding site, which can be explained by perturbations of interactions across the protomer interfaces within the KR2 complex. This study is complemented by data from time-resolved optical spectroscopy.

Nanometer‐size tin oxide particles (see Figure) with high thermal stability against particle growth have been synthesized. A low particle growth rate was achieved by doping SnO2 particles with rare earth ions during synthesis. This technology can be applied to modify the particle surface and then control growth rate and specific electric and catalyst properties, producing nanostructured materials with improved performance.

We present a comparative study using femtosecond pump/probe spectroscopy in the visible and infrared of the early photodynamics of solubilized proteorhodopsin (green absorbing variant) in D(2)O with deprotonated (pD 9.2) and protonated (pD 6.4) primary proton acceptor Asp-97. The vis-pump/vis-probe experiments show a kinetic isotope effect that is more pronounced for alkaline conditions, thus decreasing the previously reported pH-dependence of the primary reaction of proteorhodopsin in H(2)O. This points to a pH dependent H-bonding network in the binding pocket of proteorhodopsin, that directly influences the primary photo-induced dynamics. The vis-pump/IR-probe experiments were carried out in two different spectral regions and allowed to monitor the retinal C=C (1500 cm(-1)-1580 cm(-1)) and C=N stretching vibration as well as the amide I mode of the protein (1590 cm(-1)-1680 cm(-1)). Like the FTIR spectra of the K intermediate (PR(K)-PR difference spectra) in this spectral range, the kinetic parameters and also the quantum efficiency of photo-intermediate formation are found to be virtually independent of the pD value.

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