DHA-induced changes of supported lipid membrane morphology

Docosahexaenoic acid (DHA) is a polyunsaturated long fatty acid known to have fundamental effects on cell membrane function. Here, the effect of DHA on phosphocholine-supported lipid bilayers was measured using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. Above a concentration of 60 muM (i.e., near the critical micelle concentration), DHA had drastic effects on the viscoelastic properties of the supported membranes, suggesting a more complex process and structure than simple insertion of molecules in the bilayer. Fluorescence microscopy revealed the spontaneous formation of elongated out-growths from the bilayers, which were remarkable for their length ( approximately 100 mum) and extensive coverage of the surface. These results demonstrate the applicability of QCM-D as a method to screen for conditions where membrane remodeling occurs but also that complementary techniques are required to describe in more detail the changes in viscoelastic properties of the membrane. These results are highly relevant for the present rapid development in the field of model lipid membranes aiming toward increased knowledge about processes occurring at biological surfaces.     

Approximating Band- and Energy-Limited Signals in the Presence of Jitter

This paper deals with recovering band- and energy-limited signals from a finite set of their perturbed samples taken at slightly wrong points. The perturbations in sample points reading (called jitter) and in the measurements of the corresponding samples are assumed to be bounded byγandδ, respectively. The goal is to analyze how the minimal worst-case recovery error depends onγandδ. This is accomplished by proving tight upper and lower bounds on the diameter of information. The main conclusion is that the jitter causes the error of orderγΔ^3/2+δ, whereΔis the bandwidth.     

Manufacturing of Volumetric Glass–Based Composites with Single‐ and Double‐QD Doping

Quantum dot (QD)‐based light‐emitting materials are gaining increased attention because of their easily tunable optical properties desired for various applications in biology, optoelectronics, and photonics. However, few methods can be used to manufacture volumetric materials doped with more than one type of QD other than QD‐polymer hybrids, and they often require complicated preparation processes and are prone to luminescence quenching by QD aggregation and separation from the matrix. Here, simultaneous doping of a volumetric glass‐based nanocomposite with two types of QDs is demonstrated for the first time in a single‐step process using the nanoparticle direct doping method. Glass rods doped with CdTe, CdSe/ZnS, or co‐doped with both QDs, are obtained. Photoluminescence and lifetime experiments confirm temperature‐dependent double emission with maxima at 596 and 720 nm with mean lifetimes up to 16 ns, as well as radiative energy transfer from the short wavelength–emitting QDs to the long wavelength–emitting QDs. This approach may enable the simple and cost‐efficient manufacturing of bulk materials that produce multicolor luminescence with cascade excitation pumping. Applications that could benefit from this include broadband optical fiber amplifiers, backlight systems in LCD screens, high‐power LEDs, or down‐converting solar concentrators used to increase the efficiency of solar panels.     

Evolution of the truncated Mellin moments of the parton distributions in QCD analysis

We review evolution equations for the truncated Mellin moments of the parton distributions and some their applications in QCD analysis. The main finding of the presented approach is that the nth truncated moment of the parton distribution obeys also the DGLAP equation but with a rescaled splitting function P′(z) = z ⁿ P(z). This allows one to avoid the problem of dealing with the experimentally unexplored Bjorken-x region. The evolution equations for truncated moments are universal—they are valid in each order of perturbation expansion and can be useful additional tool in analysis of unpolarized as well as polarized nucleon structure functions.     

Random iterations, fixed points and invariant CRF-horospheres in complex Banach spaces

For holomorphic noncontractive maps on (not necessarily bounded) domains in complex Banach spaces, we establish the conditions guaranteeing locally uniform convergence of random iterations and study the existence of fixed points and boundary behaviour of iterations. In particular, we show that the problem, concerning the existence of the horospheres determined by Carathéodory-Reiffen-Finsler pseudometrics defined on unbounded domains, has the solution and we prove new results of type of Julia's lemma and Wolff's theorem.     

Enantioselective organocatalytic approach to δ-lactones bearing a fused cyclohexanone scaffold

A new method based on the cascade reaction between β,γ-unsaturated-α-ketophosphonates and cyclic 1,3-dicarbonyls is reported for the synthesis of highly enantiomerically enriched δ-lactones bearing a fused cyclohexenone scaffold. The target products bearing a δ-lactone moiety and one stereogenic center were obtained in good to excellent yields (83–96%) and enantioselectivities (63:32–95:5 er). The best results were obtained in the presence of a chiral Brønsted base catalyst derived from the cinchona alkaloid quinine and modified by a squaramide moiety.     

Apparent Molar Volumes of Divalent Transition Metal Cations in Dimethyl Sulfoxide Solutions

Densities for DMSO solutions of divalent transition metal perchlorates are reported. The partial molar volumes of the hexakis-(DMSO) cations are derived and discussed in terms of variation within the series. The ligand-field effect on the partial molar volume and enthalpy of solvation is demonstrated.