Shape Matters: Anisotropy of the Morphology of Inorganic Colloidal Particles – Synthesis and Function

The shape of a crystalline particle can be defined by a characteristic set and abundance of surfaces corresponding to the lattice planes [hkl] of the crystal. The structure, the density, the electronic system, and the energy of each [hkl]‐surface is different from the others. Consequently, every morphology is also characterized by a unique free energy compared to alternative shapes at a constant surface‐to‐volume ratio. Using tools from geometrical crystallography, an attempt is made to describe the systems in terms of morphology energy landscapes. It is obvious that, similar to surface phenomena, shape‐related properties are also apparent, in particular at the nanometer‐scale. However, morphology effects go much beyond surface effects. It will be shown that not only catalytic properties differ with particle shape, but also magnetic, optical, electronic, mechanical, and self‐assembly properties are influenced. In addition, analytical methods are highlighted that are suitable for the determination of the shape of the particles. Different methods are discussed that can be found for the synthesis of anisotropic metal and metal‐oxide nanoparticles.     

Fluorination-controlled Aggregation and Intermolecular Interactions in Pt(II) Complexes with Tetradentate Luminophores

In this work we describe the synthesis and DFT-supported photophysical characterization of a series of Pt(II) complexes bearing tetradentate luminophores with increasing degree of fluorination. Aggregation into crystalline phases leads to substitution-dependent arrangements that in all cases hinder intermetallic coupling, as intermolecular interactions are dominated by hydrogen bonding and π-stacking. In amorphous matrices, on the other hand, we observed that an increasing level of fluorination favors the tendency towards Pt−Pt interaction upon aggregation, leading to a red-shifted phosphorescence, if compared with monomeric species in dilute solutions and crystalline solids.     

Frustrated Interfaces Facilitate Dynamic Interactions between Native Client Proteins and Holdase Chaperones

Molecular chaperones are crucial for cellular life to ensure that all proteins obtain their right fold and functionality. Many chaperones promiscuously bind a wide spectrum of client proteins, ranging from nascent to quasi-native and native proteins. Several recent studies have investigated, at atomic resolution, how chaperones interact with native proteins. Native proteins feature a wide variety of structural conformations, and therefore, a given chaperone cannot accomplish full surface complementarity to all of its client proteins. This limitation is circumvented by the recognition of frustrated regions on the client protein surface by the chaperone. In this interaction mode, the chaperone forms a multitude of transient local interactions with some segments of the client, whereas other parts are transiently not in favorable interactions. A permanent rearrangement of the client conformation on the chaperone occurs. Reconfiguration on the chaperone surface also gives the client a chance to fold into its correct, minimally frustrated conformation.     

Microalgae as a potential source for biodiesel production: techniques,methods, and other challenges

This paper reviews some of the most important aspects of microalgae as a potential source for biodiesel production. Microalgae are photosynthetic microorganisms that can grow rapidly in a variety of environments because of their unicellular or multicellular structure depending on the species. They have the advantage of self‐reproduction using solar energy and converting it into chemical energy via photosynthesis. This process concludes a full cycle in a few days, obtaining higher lipid yields than terrestrial crops. This review shows several techniques and some methodologies used in the biodiesel production process from microalgae as well as the challenges that must be overcome for large‐scale process and in bio‐refineries. Copyright © 2016 John Wiley & Sons, Ltd.     

Microwave dielectric properties of BaNb(2?x)TaxP2O11 (x?=?0, 0.5, 1, 1.5 and 2) ceramics

BaNb_(2−x)Ta_xP₂O₁₁ (x = 0, 0.5, 1, 1.5 and 2) ceramics were prepared by the conventional solid state ceramic route. The relative permittivity (ε_r) of the ceramics decreased from 25.3 for x = 0 to 12.9 for x = 2. BaTa₂P₂O₁₁ (x = 2) sintered at 1250°C showed good microwave dielectric properties with Q_u × f = 28,900 GHz and τ_f = − 29 ppm/°C. The addition of 5 wt% TiO₂ lowered the sintering temperature to 1225°C and improved τ_f to −6 ppm/°C with ε_r = 13.4 and Q_u × f = 17,200 GHz.     

Possibilities of laser-beam joining cemented carbides to steel

Welded joints of cemented carbides with steel are commonly present in tool production, mainly those used in the machining and mining industry. The article presents possibilities of joining cemented carbides H10S and G10 with steel C45 using laser radiation. These are the first innovative experiments carried out in Poland. Joints between cemented carbides and steel were made both directly and using spacers between the materials to be joined, which were made of copper, triple-layer solder Ag49/Cu and nickel. The joining trials were carried out at the Laser Technology Centre of the Institute of welding in Gliwice. A Triumpf disc laser (λ = 1030 nm) Tru-Disc 12002 with output power of 12 kW was used for this purpose. The laser beam was focused mostly on the steel surface to avoid direct interaction between the laser beam and the structure of cemented carbides. The assessment of joints of cemented carbides with steel C45 was conducted on the basis of metallographic evaluation, EDX analyses and microhardness measurements.