X-ray Nanodiffraction on a Single SiGe Quantum Dot inside a Functioning Field-Effect Transistor

For advanced electronic, optoelectronic, or mechanical nanoscale devices a detailed understanding of their structural properties and in particular the strain state within their active region is of utmost importance. We demonstrate that X-ray nanodiffraction represents an excellent tool to investigate the internal structure of such devices in a nondestructive way by using a focused synchotron X-ray beam with a diameter of 400 nm. We show results on the strain fields in and around a single SiGe island, which serves as stressor for the Si-channel in a fully functioning Si-metal-oxide semiconductor field-effect transistor

Benzanilide–Biphenyl Replacement: A Bioisosteric Approach to Quinoline Carboxamide-Type ABCG2 Modulators

Recently reported compounds such as UR-COP78 (<b>6</b>) are among the most potent and selective ABCG2 modulators known so far but are prone to rapid enzymatic cleavage at the central benzanilide moiety. In search for more stable analogues, according to a bioisosteric approach, a series of <i>N</i>-(biphenyl-3-yl)­quinoline carboxamides was prepared by solid phase and solution phase synthesis. The biphenyl moiety was constructed by Suzuki coupling. Inhibition of ABCB1 and ABCG2 was determined in a calcein-AM and a Hoechst 33342 microplate assay, respectively. Most synthesized compounds selectively inhibited the ABCG2 transporter at submicromolar concentrations with a maximal inhibitory effect (<i>I</i>_max) over 90% (e.g., UR-COP228 (<b>22a</b>), IC₅₀ 591 nM, <i>I</i>_max 109%; UR-COP258 (<b>31</b>), IC₅₀ 544 nM, <i>I</i>_max 112%), though with lower potency and selectivity than <b>6</b>. The biphenyl analogues are considerably more stable and demonstrate that the benzanilide core is not a crucial structural feature of quinoline carboxamide-type ABCG2 modulators

Growth Mechanism of Self-Catalyzed Group III−V Nanowires

Group III−V nanowires offer the exciting possibility of epitaxial growth on a wide variety of substrates, most importantly silicon. To ensure compatibility with Si technology, catalyst-free growth schemes are of particular relevance, to avoid impurities from the catalysts. While this type of growth is well-documented and some aspects are described, no detailed understanding of the nucleation and the growth mechanism has been developed. By combining a series of growth experiments using metal−organic vapor phase epitaxy, as well as detailed in situ surface imaging and spectroscopy, we gain deeper insight into nucleation and growth of self-seeded III−V nanowires. By this mechanism most work available in literature concerning this field can be described

<i>Tetra</i>-Substituted Pyridinylimidazoles As Dual Inhibitors of p38α Mitogen-Activated Protein Kinase and c‑Jun <i>N</i>‑Terminal Kinase 3 for Potential Treatment of Neurodegenerative Diseases

<i>Tetra</i>-substituted imidazoles were designed as dual inhibitors of c-Jun <i>N</i>-terminal kinase (JNK) 3 and p38α mitogen-activated protein (MAP) kinase. A library of 45 derivatives was prepared and evaluated in a kinase activity assay for their ability to inhibit both kinases, JNK3 and p38α MAP kinase. Dual inhibitors with IC₅₀ values down to the low double-digit nanomolar range at both enzymes were identified. The best balanced dual JNK3/p38α MAP kinase inhibitors are <b>6m</b> (IC₅₀: JNK3, 18 nM; p38α, 30 nM) and <b>14d</b> (IC₅₀: JNK3, 26 nM; p38α, 34 nM) featuring both excellent solubility and metabolic stability. They may serve as useful tool compounds for preclinical proof-of-principle studies in order to validate the synergistic role of both kinases in the progression of Huntington’s disease

Unit Cell Structure of Crystal Polytypes in InAs and InSb Nanowires

The atomic distances in hexagonal polytypes of III−V compound semiconductors differ from the values expected from simply a change of the stacking sequence of (111) lattice planes. While these changes were difficult to quantify so far, we accurately determine the lattice parameters of zinc blende, wurtzite, and 4H polytypes for InAs and InSb nanowires, using X-ray diffraction and transmission electron microscopy. The results are compared to density functional theory calculations. Experiment and theory show that the occurrence of hexagonal bilayers tends to stretch the distances of atomic layers parallel to the <i>c</i> axis and to reduce the in-plane distances compared to those in zinc blende. The change of the lattice parameters scales linearly with the hexagonality of the polytype, defined as the fraction of bilayers with hexagonal character within one unit cell