17 research outputs found
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
Alternative Splicing of Vasohibin-1 Generates an Inhibitor of Endothelial Cell Proliferation, Migration, and Capillary Tube Formation
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><sub>max</sub>) over
90% (e.g., UR-COP228 (<b>22a</b>), IC<sub>50</sub> 591 nM, <i>I</i><sub>max</sub> 109%; UR-COP258 (<b>31</b>), IC<sub>50</sub> 544 nM, <i>I</i><sub>max</sub> 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
Structural Investigations of Core−shell Nanowires Using Grazing Incidence X-ray Diffraction
A Landmark in Turbulent Times: The Meaning and Relevance of the Synod of Dordt (1618-1619)
A Landmark in Turbulent Times:The Meaning and Relevance of the Synod of Dordt (1618-1619)
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 IC<sub>50</sub> 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> (IC<sub>50</sub>: JNK3, 18 nM; p38α, 30 nM) and <b>14d</b> (IC<sub>50</sub>: 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