Effect of composition on the point of zero charge of RuO2 + TiO2 mixed oxides

RuO₂ + TiO₂ mixed oxides have been prepared by thermal decomposition of RuCl₃ + TiCl₄ at 450°C. The structural features have been investigated by X-ray diffraction, while the Braunauer-Emmett-Teller method has been used to determine the surface area of the powders. The point of zero charge (pzc) has been measured by potentiometric titration of oxide suspensions in KNO₃ solution. The charge-pH curves have been transformed into capacitance values which have been used at the pzc to estimate in-situ the real surface area and the inner layer capacitance. In the absence of RuO₂, Tio₂ is mainly in the anatase form. The rutile form of TiO₂ has a pzc close to that of RuO₂ which results in a pzc varying very little between 40 and 100% RuO₂. The same is the case with the real surface area. This is in accord with the performances of electrodes showing RuO₂-like properties down to 30–40% RuO₂. The behaviour of RuO₂ + TiO₂ oxides is structurally, electronically and chemically dominated by that of the RuO₂ component.     

Oncidinol—a novel diacylglycerol from Ornithophora radicans Barb. Rodr. (Orchidaceae) floral oil

The structure and absolute configuration of a novel diacylglycerol, (2S,3′R,6′R)-1-acetyl-2-[3′,6′-diacetoxyeicosanyl)-glycerol 1, named oncidinol, from the Ornithophora radicans floral oil was elucidated from spectroscopic data and by applying the Mosher method.     

Kinetics and mechanism of bromate-bromide reaction catalyzed by acetate

The initial rate of the bromate-bromide reaction, BrO3- + 5Br- + 6H+ --> 3Br2 + 3H2O, has been measured at constant ionic strength, I = 3.0 mol L(-1), and at several initial concentrations of acetate, bromate, bromide, and perchloric acid. The reaction was followed at the Br2/Br3- isosbestic point (lambda = 446 nm) by the stopped-flow technique. A very complex behavior was found such that the results could be fitted only by a six term rate law, nu = k1[BrO3-][Br-][H+]2 + k2[BrO3-][Br-]2[H+]2 + k3[BrO3-][H+]2[acetate]2 + k4[BrO3-][Br-]2[H+]2[acetate] + k5[BrO3-][Br-][H+]3[acetate]2 + k6[BrO3-][Br-][H+]2[acetate], where k1 = 4.12 L3 mol(-3) s(-1), k2 = 0.810 L4 mol(-4) s(-1), k3 = 2.80 x 10(3) L4 mol(-4) s(-1), k4 = 278 L5 mol(-5) s(-1), k5 = 5.45 x 10(7) L6 mol(-6) s(-1), and k6 = 850 L4 mol(-4) s(-1). A mechanism, based on elementary steps, is proposed to explain each term of the rate law. This mechanism considers that when acetate binds to bromate it facilitates its second protonation.     

Reduction Methods for Total Reaction Cross Sections

The most frequently used methods to reduce fusion and total reaction excitation functions were investigated in a very recent paper Canto et al. (Phys Rev C 92:014626, 2015). These methods are widely used to eliminate the influence of masses and charges in comparisons of cross sections for weakly bound and tightly bound systems. This study reached two main conclusions. The first is that the fusion function method is the most successful procedure to reduce fusion cross sections. Applying this method to theoretical cross sections of single channel calculations, one obtains a system independent curve (the fusion function), that can be used as a benchmark to fusion data. The second conclusion was that none of the reduction methods available in the literature is able to provide a universal curve for total reaction cross sections. The reduced single channel cross sections keep a strong dependence of the atomic and mass numbers of the collision partners, except for systems in the same mass range. In the present work we pursue this problem further, applying the reduction methods to systems within a limited mass range. We show that, under these circumstances, the reduction of reaction data may be very useful.     

Methods and Supports for Immobilization and Stabilization of Cyclomaltodextrin Glucanotransferase from Thermoanaerobacter

Thermoanaerobacter cyclomaltodextrin glucanotransferase (CGTase) was immobilized using different supports and immobilization methods to study the effect on activity recovery. The enzyme covalently attached into glyoxyl-silica showed low activity recovery of 1.5%. The hydrophobic adsorption of the enzyme on Octadecyl-Sepabeads yielded also low activity recovery, 3.83%, and the enzyme could easily leak from the support at low ionic strength, although the immobilization yield was satisfactory, approximately 76%. The CGTase encapsulated in a sol–gel matrix gave an activity recovery of 6.94% and maximum cyclization activity at 60 °C, at pH 6.0. The half-time life at 60 °C, pH 6.0, in the presence of substrate was 100 min, which was lower than that of the free enzyme. The best activity recovery in this work (6.94%) is approximately five times smaller than that obtained previously using glyoxyl-agarose as support and covalent immobilization. Thus, the best support and method we tested so far for immobilization of CGTase is covalent attachment on glyoxyl-agarose.     

Measurement of elastic properties of prostate cancer cells using AFM

This communication reports that three prostate cancer cells of differing metastatic potential were discriminated based on their Young's moduli (LNCaP - 287 +/- 52 N m(-2), PC-3 - 1401 +/- 162 N m(-2) and BPH - 2797 +/- 491 N m(-2)) which were determined using AFM and the Hertz model.