Biotin-Functionalized Block Catiomers as an Active Targeting Approach in Gene Delivery

Recently, biotin (vitamin H) has been described as a ligand for active targeting and it has been found that many cancer cells overexpress the biotin receptor. In this study a biotin-conjugated block copolymer, biotin-poly(2-ethyl-2-oxazoline)-block-poly{N '-[N-(2-aminoethyl)-2-aminoethyl]aspartamide} (biotin-pEtOx-b-pASP(DEA) is synthesized by a living cationic polymerization of the pEtOx-block followed by the nucleophilic ringopening polymerization of the pASP-block. The biotin moiety is coupled to the pEtOx-b-pASP precursor by a Cu(I) mediated azide-alkyne click chemistry and finally, the diethylamine (DEA) side chain is introduced by a polymer analogous reaction. The final polymer P1 formed polyplexes in the presence of plasmid DNA that are characterized with respect to N/P ratio, size, zeta potential, and shape compared to a control polymer P2 without biotin. In addition, HEK293 cells are transfected with these polyplexes and the number of fluorescent HEK293 cells is evaluated to assess the influence of polymer nature on the activity of the micelles. Flow cytometric analysis revealed a significantly higher uptake of the biotin-PEtOx-PASP(DEA)/pDNA micelle than the PEtOx-PASP(DEA)/pDNA micelle against HEK293 cells at a low N/P ratio of 20, consistent with the transfection results whereas at higher N/P ratio no difference can be observed anymore between the two polymers.     

Damascene TiN-Gd2O3-gate stacks: Gentle fabrication and electrical properties

In this work, we present MOS capacitors and field effect transistors with a crystalline gadolinium oxide (Gd₂O₃) gate dielectric and metal gate electrode (titanium nitride) fabricated in a gentle damascene gate last process. Details of the gate last process and initial results on MOS devices with equivalent oxide thicknesses (EOT) of 3.0 nm and 1.5 nm, respectively, are shown.     

BCl3 modified tris(dichloromethylsilylethyl)borane as a precursor for SiBCN ceramics applied in lithium-ion battery anodes

Tris(dichloromethylsilylethyl)borane is a compound containing a B–C bond and Cl and H elements. Herein, we propose a novel method to synthesize polyborosilazanes using tris(dichloromethylsilylethyl)borane and boron trichlorosilane as boron sources and hexamethyldisilazane as a nitrogen source. The microstructure and chemical composition of the as-synthesized polyborosilazanes and as-annealed SiBCN ceramics were investigated using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, Raman spectroscopy, scanning electron microscope, and transmission electron microscope methods. The organic precursors were converted entirely into inorganic ceramics at 800 °C, and the ceramic yield of the polyborosilazanes was 88% at 1000 °C. SiBCN ceramics with irregular shapes contained chemical bonds of B–N, Si–N, and Si–C at 1500 °C and retained an amorphous structure below 1600 °C. After the first cycle, the fabricated SiBCN ceramic anodes exhibited a reversible capacity of 261.3 mA h/g, which was 2.6 times that reported in the literature (101 mA h/g). The discharge capacity decreased to 157.6 mA h/g after 30 cycles. The satisfactory electrochemical performance of the resulting SiBCN ceramic anodes can be attributed to the formation of conductive carbon species favoring the transport properties of lithium ion.     

Investigation of air bending of structured sheet metals by multistage FE simulation

The nonparametric location–scale statistic is introduced for a change-point problem. A combination of the Wilcoxon and Mood statistics is extended to the change-point setting. The limiting distribution of proposed statistic is derived for testing the null hypothesis of no change. The finite sample critical value of the suggested statistic is estimated by simulation studies. The accuracy of detecting a change point is investigated by simulation studies for various distributions. The method is illustrated by the analysis of real data.     

Automated generation of physical surrogate vehicle models for crash optimization

International Journal of Mechanics and Materials in Design - A challenge in the design and optimization of vehicle structures is the high computational costs required for crash analysis. In this...     

Oxidation Behavior of Superalloy IN 713 Fabricated by Metal Injection Molding

Oxidation of Metals - The oxidation behavior of superalloy IN 713 fabricated by metal injection molding (MIM) was investigated and compared with standard cast material plus hot isostatic pressing...     

Fine-sorting one-dimensional particle-in-cell algorithm with Monte-Carlo collisions on a graphics processing unit

Particle-in-cell (PIC) simulations with Monte-Carlo collisions are used in plasma science to explore a variety of kinetic effects. One major problem is the long run-time of such simulations. Even on modern computer systems, PIC codes take a considerable amount of time for convergence. Most of the computations can be massively parallelized, since particles behave independently of each other within one time step. Current graphics processing units (GPUs) offer an attractive means for execution of the parallelized code. In this contribution we show a one-dimensional PIC code running on NVIDIA^® GPUs using the CUDA^™ environment. A distinctive feature of the code is that size of the cells that the code uses to sort the particles with respect to their coordinates is comparable to size of the grid cells used for discretization of the electric field. Hence, we call the corresponding algorithm “fine-sorting”. Implementation details and optimization of the code are discussed and the speed-up compared to classical CPU approaches is computed.     

Konzeptionelles hydrogeologisches Modell zur Analyse und Bewertung von Verweilzeiten in Hessen

A regional scale conceptual hydrogeological model has been developed for evaluating residence times of groundwater in the upper aquifers and unsaturated zone within the Federal State of Hessen (Germany). The model is based on digitally available data bases and was applied with a spatial resolution of 60?m×60?m. Typical residence times for areas of unconsolidated deposits ranged between 10 and 25 years, whereas residence times of less than 5?years were found in areas of consolidated rock. Within the EU-Water Framework Directive, these results may help in assessing temporal and regional impacts of measures to reduce mass loading from the surface to groundwater. This will lead to better decisions, for instance whether additional measures to reach the environmental objectives should be applied.     

Nano-scale modification of 2D surface structures exposed to 6 keV carbon ions: Experiment and modeling

In this work, a Si pitch grating with typical lateral dimensions of 200-250 nm was exposed to 6 keV C⁺ ions at normal incidence and at an angle of 42° both parallel and perpendicular to the grating structure. In contrast to volatile and recycling ions (like Ar⁺ or H⁺), non-recycling ions are able to modify the surface not only due to sputtering, but also due to implantation of incident ions and the re-deposition of projectile atoms following sputtering or reflection. The target-projectile combination used in this work is an example of such a system forming a mixed Si-C surface. The interaction between the ion beam and the surface has been studied both experimentally and numerically with the focus on validation of the numerical model of the newly developed SDTrimSP-2D code. SDTrimSP-2D is capable of following the evolution of the Si-C system including ion-surface interactions with 2D micro- and nano-structured surfaces. The SDTrimSP-2D code takes the interdependency of surface morphology, sputtering and implantation into account. The simulated surface morphology has been compared to cross-sections of bombarded Si pitch grating obtained by SEM, revealing good agreement between experiment and simulation. The calculations also provide improved insight into the mechanisms of surface modification by sputtering, implantation and material transport by redeposition.