Indium containing sillenite semiconductor: Synthesis,structural, spectroscopic,and thermogravimetric analysis

Sillenite-type ceramics are non-centrosymmetric phases of ongoing research interest because of their structural defects and optoelectronic properties. We report a series of sillenite compounds with a general composition Bi₁₂(Bi³⁺_4/5−3xIn³⁺_5x□_1/5−2x)O_19.2+3x□_0.8−3x for x = 0.03–0.27 to understand how the crystal–physicochemical properties change with a successive filling of empty Bi³⁺ positions in the tetrahedral site by In³⁺ cation. Conventional solid-state synthesis method is used to prepare the microcrystalline samples. Each sample is characterized by X-ray diffraction, Raman, UV/Vis diffuse reflectance spectroscopy, and thermogravimetry (TG/DSC). X-ray powder data Rietveld refinement reveals that phase-pure samples can be obtained for x = 0.03–0.08 in the space group I23. Appearance of starting In₂O₃ as minor phases with the final products for 0.10 < x < 0.27 suggests for x_max = 0.08. The successive decrease of the lattice parameter indicates the incorporation of smaller In³⁺ cations in the structure. The effect of the lone electron pairs of Bi³⁺ and the structural cation vacancies lead to the modification of the interatomic bond lengths. At least one Raman active phonon mode shows hardening for decreasing cation vacancy concentration in the system. The bandgap energy increases with increasing indium content. An additional absorption band at lower energy for x = 0.03–0.08 complements the theoretical study, which completely disappears for x > 0.08. The stronger In–O bonds play pivotal roles in the thermal stability of the phases studied by TGA/DSC analysis.     

Membranbasierte Bereitstellung von CO2 für die dezentrale Algenproduktion in einer Bioenergiefassade

This study emphasizes the importance of a sustainable energy supply with regard to climate change. A way is shown how a de-centralized heat supply in urban areas with renewable energies can be combined with algae production. The decentrally generated CO₂ emissions are made usable for biomass production by means of membrane separation technology. The operating behavior of the CO₂-selective membrane materials was observed over an operating period of almost 10 years. This provides solid evidence of the operability of the polymer membrane and membrane module technology. It enables further optimization of the separation process for future applications, also in a wider range of applications.     

Optical and Mechanical Properties of Thin PTFE Films,Deposited from a Gas Phase

Thin polytetrafluoroethylene (PTFE) films are produced by deposition from a gas phase by two methods: electron-enhanced vacuum deposition (EVD) and EVD + low-temperature plasma (LTP). Structure, morphology, and composition of the films are studied by IR spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. They are close to the structure of bulk PTFE. The roughness of the films’ surface is changed with gas pressure and LTP power variations. Films are transparent from UV to near-infrared regions. Refractive and extinction indices and their anisotropy are measured by spectral ellipsometry. They are tuned by variations of deposition conditions. Hardness and Young modulus of the films are increased if EVD + low power LTP is used for film deposition. Use of EVD + LTP also increases thermal stability of the films. Contact angle of the films corresponds to the bulk PTFE. The PTFE molecules oriented are preferentially in perpendicular direction to the substrate surface.     

Assessment of low-frequency aeroacoustic emissions of a wind turbine under rapidly changing wind conditions based on an aero-servo-elastic CFD simulation

A meteorologically challenging situation that represents a demanding control task (rotational speed, pitch and yaw) for a wind turbine is presented and its implementation in a simulation is described. A high-fidelity numerical process chain, consisting of the computational fluid dynamics (CFD) solver FLOWer, the multi-body system (MBS) software SIMPACK and the Ffowcs Williams-Hawkings code ACCO, is used. With it, the aerodynamic, servoelastic and aeroacoustic (<20 Hz) behaviour of a generic wind turbine during a meteorological event with strong and rapid changes in wind speed and direction is investigated. A precursor simulation with the meteorological model system PALM is deployed to generate realistic inflow data. The simulated strong controller response of the wind turbine and the resulting aeroelastic behaviour are analysed. Finally, the low-frequency sound emissions are evaluated and the influence of the different operating and flow parameters during the variable inflow is assessed. It is observed that the wind speed and, linked to it, the rotational speed as well as the turbulence intensity are the main influencing factors for the emitted low-frequency sound power of the wind turbine. Yawed inflow, on the other hand, has little effect unless it changes the operational mode to load reduction, resulting in a swap of the main emitter from the blades to the tower.     

Binding Methylarginines and Methyllysines as Free Amino Acids: A Comparative Study of Multiple Host Classes**

Methylated free amino acids are an important class of targets for host-guest chemistry that have recognition properties distinct from those of methylated peptides and proteins. We present comparative binding studies for three different host classes that are each studied with multiple methylated arginines and lysines to determine fundamental structure-function relationships. The hosts studied are all anionic and include three calixarenes, two acyclic cucurbiturils, and two other cleft-like hosts, a clip and a tweezer. We determined the binding association constants for a panel of methylated amino acids using indicator displacement assays. The acyclic cucurbiturils display stronger binding to the methylated amino acids, and some unique patterns of selectivity. The two other cleft-like hosts follow two different trends, shallow host (clip) following similar trends to the calixarenes, and the other more closed host (tweezer) binding certain less-methylated amino acids stronger than their methylated counterparts. Molecular modelling sheds some light on the different preferences of the various hosts. The results identify hosts with new selectivities and with affinities in a range that could be useful for biomedical applications. The overall selectivity patterns are explained by a common framework that considers the geometry, depth of binding pockets, and functional group participation across all host classes.     

Wechselwirkungen in Kristallen. 96. Darstellung und Strukturen von Salzen [RnN⊕H…︁NRn][B⊖(C6H5)4] mit Prototyp-Wasserstoffbrücken N⊕H…︁N

Interactions in Crystals. 96. Preparation and Structures of Salts [R_nN^⊕H…︁NR_n][B^⊖(C₆H₅)₄] with Prototype Hydrogen Bridges N^⊕H…︁N Straightforward crystallization of ammonium salts [R_nN^⊕H] X^⊖ added lithium tetraphenylborate, and amine R_nN from acetone solution yields salts [R_nN^⊕H…︁NR_n][B^⊖(C₆H₅)₄] with the (under the conditions) unprotonated anions and the cations with prototype hydrogen bridges N^⊕H…︁N. The structures of both identically substituted R_nN (methylamine, trimethylamine, quinuclidine, diazabicyclooctane, and pyridine) as well as two-component cation species (quinuclidine…︁pyridine and diazabicyclooctane…︁pyridine) are reported and discussed. A Cambridge Structural Database search defines the area of charged N^⊕H…︁N interactions which can be correlated with both pK values and PM3 formation enthalpies. Additional information is provided by PM3 calculations based on the experimental structure coordinates. The charge distribution within the hydrogen bridges N^⊕H…︁N varies considerably with the individual proton donors N⁺H and proton acceptors N: Positive charges are highest at protonated quinuclidine and diazabicyclooctane centers and lowest at pyridine N acceptor centers.     

Effect of Amino Acid Substitutions on 70S Ribosomal Binding,Cellular Uptake,and Antimicrobial Activity of Oncocin Onc112

Proline-rich antimicrobial peptides (PrAMPs) are promising candidates for the treatment of infections caused by high-priority human pathogens. Their mode of action consists of (I) passive diffusion across the outer membrane, (II) active transport through the inner membrane, and (III) inhibition of protein biosynthesis by blocking the exit tunnel of the 70S ribosome. We tested whether in vitro data on ribosomal binding and bacterial uptake could predict the antibacterial activity of PrAMPs against Gram-negative and Gram-positive bacteria. Ribosomal binding and bacterial uptake rates were measured for 47 derivatives of PrAMP Onc112 and compared to the minimal inhibitory concentrations (MIC) of each peptide. Ribosomal binding was evaluated for ribosome extracts from four Gram-negative bacteria. Bacterial uptake was assessed by quantifying each peptide in the supernatants of bacterial cultures. Oncocin analogues with a higher net positive charge appeared to be more active, although their ribosome binding and uptake rates were not necessarily better than for Onc112. The data suggest a complex mode of action influenced by further factors improving or reducing the antibacterial activity, including diffusion through membranes, transport mechanism, secondary targets, off-target binding, intracellular distribution, and membrane effects. Relying only on in vitro binding and uptake data may not be sufficient for the rational development of more active analogues.