Design and Preparation of Single‐Chain Nanocarriers Mimicking Disordered Proteins for Combined Delivery of Dermal Bioactive Cargos

Inspired by the multifunctionality of vitamin D‐binding protein and the multiple transient‐binding behavior of some intrinsically disordered proteins (IDPs), a polymeric platform is designed, prepared, and characterized for combined delivery of dermal protective and anticancer bioactive cargos on the basis of artificial single‐chain nano‐objects mimicking IDPs. For the first time ever, simultaneous delivery of folic acid or vitamin B₉, and hinokitiol, a relevant natural bioactive compound that exhibits anticancer activity against human malignant melanoma cells, from these multidirectionally self‐assembled unimolecular nanocarriers is illustrated.

     

High quantum efficiency UV detection using a‐Se based photodetector

High‐sensitivity ultraviolet (UV) photodetection has been attempted by utilizing the carrier multiplication effect in amorphous selenium. The prototype photodetector presented in this Letter showed an extremely high sensitivity to UV light, so that up to 1000 carriers are generated per incident photon. This result should lead to the development of an ultrahigh‐sensitivity photodetector that can be used for spectrometric applications covering the visible to UV region. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Prediction of vicinal proton–proton coupling constants 3 J HH from density functional theory calculations

Vicinal coupling constants ³ J _HH have been calculated at the optimized geometries for a series of selected molecules with the aim of developing a practical procedure for predicting this kind of coupling. Calculations of couplings and optimizations of molecular geometries have been carried out at the DFT/B3LYP level using a moderate sized basis set. When the Fermi contact contributions to ³ J _HH calculated for 25 mono- and 23 1,1-di-substituted ethanes are multiplied by a factor of 0.904, the corresponding predicted couplings J ^pre are in good agreement with the experimental J ^exp couplings, with standard deviation σ of 0.10?Hz. When such a comparison is carried out for the remaining sets of molecules the σ deviation increases to 0.26?Hz for a dataset of 21 couplings from 11 monosubstituted cyclohexanes, to 0.19?Hz for a dataset of 40 couplings from 6 norbornane type molecules and to 0.25?Hz for a dataset of 54 couplings from 14 three-membered rings. For the complete dataset of 163 couplings the?σ?deviation amounts to 0.20?Hz. This figure is further reduced to 0.17?Hz by adding to the J ^pre coupling a small correction given by the term ?0.15cos?, depending on the dihedral angle ? between the coupled protons. A larger σ deviation of 0.31?Hz was reported for the best empirically parameterized extended Karplus equation. DFT J ^pre values could be further improved by more accurate calculations for the pertinent substituted ethane constituents of the molecule in question by applying a substituent effect model.     

High-pressure phase transition in CaTiOSiO4 titanite

The P2₁/a to A2/a transition in titanite has been studied at high pressure (and room temperature) by X-ray powder diffraction. On the basis of the disappearance of k + l= odd reflections from the diffraction pattern, the transition was located between 3·351(3) and 3·587(3) GPa. The variation with pressure of the spontaneous strain in the P2₁/a phase indicates that the transition has an effective critical exponent significantly less than 1/2. Within the uncertainties of the data, the transition could be weakly first-order in character or be continuous with an effective critical exponent in the range of ～0·13-0·25. The A2/a to P2₁/a transition is accompanied by a significant expansion of the a-axis as a result of the bond-valence sum requirements of the Ti atoms: in the high-pressure phase they occupy the centres of the TiO₆ octahedra, but they are displaced along the a-axis in the P2₁/a phase to form alternating short and long Ti-O bonds.     

Observed structural change in poly-n-butyl isocyanate

We report a conformational change observed in poly-n-butyl isocyanate (PBIC) dissolved in carbon tetrachloride (CCl₄) with temperature. This change was detected by measuring the reduced viscosity of the polymer solution with a Zimm-Crothers type viscometer of very low shear rate; we found a reversible jump in reduced viscosity whose amplitude depends on concentration, but its position is only molecular weight dependent. This jump goes from lower to higher values of reduced viscosity when we increase the temperature, corresponding to an increase in the hydrodynamic volume of the chain. The largest size of the jump we found was about 3.5% of the viscosity value, and the jump decreased when the concentration approached the overlap concentration c?.     

Intramolecular surfaces for vicinal proton–proton coupling constants 3JHH

Equations for the intramolecular surfaces of the ³J_HH coupling constants in ethane, ethylene, and acetylene are formulated, and the corresponding coefficients are estimated from calculations at the DFT/B3LYP level. The chosen variables are changes in bond lengths, in the torsion angle φ between the coupled protons H_a and H_b, in bond angles, and in dihedral angles. The ³J_HH surface of ethane is formulated as an extended Karplus equation with the coefficients of a truncated Fourier series on the torsion angle φ expanded as second-order Taylor series in the chosen variables taking into account the invariance of ³J_HH under reflections and rotations of nuclear coordinates. Partial vibrational contributions from linear and square terms corresponding to changes in the geometry of the H_a ? C_a ? C_b ? H_b fragment are important while those from cross terms are small with a few exceptions. The ³J_HH surface of ethane is useful to predict contributions to ³J_HH from changes in local geometry of derivatives but vibrational contributions are predicted less satisfactorily. The predicted values at the B3LYP/BS2 level of the ³J_HH couplings (vibrational contributions at 300 K) from equilibrium geometries are 9.79 (?0.17) for acetylene, and 17.08 (1.93) and 10.73(0.93) for the trans and cis couplings of ethylene.     

Preparation and characterization of cobalt ferrite nanoparticles coated with fucan and oleic acid

Cobalt ferrite has attracted considerable attention in recent years due to its unique physical properties such as high Curie temperature, large magnetocrystalline anisotropy, moderate saturation magnetization, large magnetostrictive coefficient, excellent chemical stability and mechanical hardness. In this work we present the preparation, of fucan coated cobalt ferrite nanoparticles by a modified co-precipitation method and the study of their structural, microstructural and magnetic characteristics for their application as a solid support for enzymes immobilization and other biotechnology applications. Aqueous suspensions of magnetic particles were prepared by coprecipitation of Fe(III) and Co(II) in the presence of NaOH, acid oleic and fucan polymer. The X-ray diffraction indicates that the funtionalization does not degrade the core cobalt ferrite. The infrared (FTIR) bands, indicate the functional characteristics of the coating on the cobalt ferrite. Mössbauer spectra at room temperature indicate the presence of a broadened sextet plus a doublet which is typical of superparamagnetic relaxation. For the Co-ferrite uncoated and coated with fucan the doublets have areas of 36.1 % and 40.3 % respectively, indicating the presence of non-interacting particles and faster relaxation time. The Co-ferrite coated with oleic acid and oleic acid plus fucan have areas around 17.5 % and 17.1 % respectively which indicate a weak superparamagnetic relaxation due to a slow relaxation time. The magnetization measurements of the cobalt ferrite nanoparticles with and without coating confirm that they are superparamagnetic and this behavior is produced by the core nanoparticles rather than the coatings. The cobalt ferrite nanoparticles coated with oleic acid presented the highest magnetization than when coating with fucan.     

On the Finite Increment Calculus method for stabilizing advection‐diffusion equations,analysis and computation of the stabilization parameter

In this work we are concerned with the finite increment calculus (FIC) method. The method has been developed for efficient approximation of advection‐diffusion equations with high Péclet numbers. Since the natural application of FIC is within the framework of the FEM, we consider the BVP in a weak sense on finite dimensional spaces. Here we provide a result on existence and uniqueness of the solution as well as an error analysis. Also we propose a choice of the stabilization parameter. We test the method on some troublesome 2D problems. Copyright © 2011 John Wiley & Sons, Ltd.