Macro modelling and homogenization for transformation induced plasticity of a low-alloy steel

Metal forming processes are important technologies for the production of engineering structures. In order to optimize the resulting material properties, it becomes necessary to simulate the entire forming process by taking into account physical effects such as phase transformations. In this work, we concentrate on the phase change from austenite to martensite and present a macroscopic material model, which combines the effect of classical plasticity with the effect of transformation induced plasticity (TRIP). An extensive experimental database for a low-alloy steel is used for parameter identification, thus taking into account the effects of uniaxial compressive and tensile stress on the kinetics of phase transformation at different temperatures. For temperatures below the martensite start temperature with simultaneous stresses above the yield limit, it is difficult to obtain experimental data. Consequently, a numerical homogenization technique is employed for this case. In a further part of this paper, an effective integration scheme is provided, which is implemented into a commercial finite element program. In a finite element simulation, the austenite to martensite phase transformation in a shaft subjected to thermal loading is investigated.     

Squalenyl Hydrogen Sulfate Nanoparticles for Simultaneous Delivery of Tobramycin and an Alkylquinolone Quorum Sensing Inhibitor Enable the Eradication of P. aeruginosa Biofilm Infections

Elimination of pulmonary Pseudomonas aeruginosa (PA) infections is challenging to accomplish with antibiotic therapies, mainly due to resistance mechanisms. Quorum sensing inhibitors (QSIs) interfering with biofilm formation can thus complement antibiotics. For simultaneous and improved delivery of both active agents to the infection sites, self-assembling nanoparticles of a newly synthesized squalenyl hydrogen sulfate (SqNPs) were prepared. These nanocarriers allowed for remarkably high loading capacities of hydrophilic antibiotic tobramycin (Tob) and a novel lipophilic QSI at 30 % and circa 10 %, respectively. The drug-loaded SqNPs showed improved biofilm penetration and enhanced efficacy in relevant biological barriers (mucin/human tracheal mucus, biofilm), leading to complete eradication of PA biofilms at circa 16-fold lower Tob concentration than Tob alone. This study offers a viable therapy optimization and invigorates the research and development of QSIs for clinical use.     

Ordering properties and interpretation of radiation damage IN Au–15 at.% Ag alloys

The equilibrium value of the electrical resistivity of Au–16.25 at.% Ag has been determined as a function of temperature. In addition, isochronal annealing of quenched Au–15 at.% Ag alloys has been studied by means of resistivity measurements. Both types of experiments indicate that in these alloys a decrease of the degree of order gives rise to an increase of the electrical resistivity. This result confirms the previous interpretation of the radiation damage and its recovery in low-temperature electron-irradiated Au–15 at.% Ag alloys in terms of the two-interstitial model.     

A Modular Synthesis of Teraryl‐Based α‐Helix Mimetics,Part 1: Synthesis of Core Fragments with Two Electronically Differentiated Leaving Groups

Teraryl‐based α‐helix mimetics have proven to be useful compounds for the inhibition of protein–protein interactions (PPI). We have developed a modular and flexible approach for the synthesis of teraryl‐based α‐helix mimetics. Central to our strategy is the use of a benzene core unit featuring two leaving groups of differentiated reactivity in the Pd‐catalyzed cross‐coupling used for terphenyl assembly. With the halogen/diazonium route and the halogen/triflate route, two strategies have successfully been established. The synthesis of core building blocks with aliphatic (Ala, Val, Leu, Ile), aromatic (Phe), polar (Cys, Lys), hydrophilic (Ser, Gln), and acidic (Glu) amino acid side chains are reported.