875 research outputs found
Design considerations for thermostatic fin spacecraft temperature control
Design considerations for thermostatic fin spacecraft temperature contro
Low-energy Dipole Excitations in Nuclei at the N=50,82 and Z=50 Shell Closures as Signatures for a Neutron Skin
Low-energy dipole excitations have been investigated theoretically in N=50,
several N=82 isotones and the Z=50 Sn isotopes. For this purpose a method
incorporating both HFB and multi-phonon QPM theory is applied. A concentration
of one-phonon dipole strength located below the neutron emission threshold has
been calculated in these nuclei. The analysis of the corresponding neutron and
proton dipole transition densities allows to assign a genuine pattern to the
low-energy excitations and making them distinct from the conventional GDR
modes. Analyzing also the QRPA wave functions of the states we can identify
these excitations as Pygmy Dipole Resonance (PDR) modes, recently studied also
in Sn and N=82 nuclei. The results for N=50 are exploratory for an experimental
project designed for the bremsstrahlung facility at the ELBE accelerator.Comment: Nuclear Physics in Astrophysics III Conference, 26 - 31 March 2007,
Forschungszentrum Dresden-Rossendorf, German
E(5), X(5), and Prolate to Oblate Shape Phase Transitions in Relativistic Hartree Bogoliubov Theory
Relativistic mean field theory with the NL3 force is used for producing
potential energy surfaces (PES) for series of isotopes suggested as exhibiting
critical point symmetries. Relatively flat PES are obtained for nuclei showing
the E(5) symmetry, while in nuclei corresponding to the X(5) case, PES with a
bump are obtained. The PES corresponding to the Pt chain of isotopes suggest a
transition from prolate to oblate shapes at 186-Pt.Comment: 21 pages, LaTeX, including 14 .eps figure
A phase I dose-escalation study of TAK-733, an investigational oral MEK inhibitor, in patients with advanced solid tumors.
Purpose TAK-733, an investigational, selective, allosteric MEK1/2 inhibitor, has demonstrated antitumor effects against multiple cancer cell lines and xenograft models. This first-in-human study investigated TAK-733 in patients with solid tumors. Methods Patients received oral TAK-733 once daily on days 1-21 in 28-day treatment cycles. Adverse events (AEs) were graded using the Common Terminology Criteria for AEs version 3.0. Response was assessed using RECIST v1.1. Blood samples for TAK-733 pharmacokinetics and pharmacodynamics (inhibition of ERK phosphorylation) were collected during cycle 1. Results Fifty-one patients received TAK-733 0.2-22 mg. Primary diagnoses included uveal melanoma (24 %), colon cancer (22 %), and cutaneous melanoma (10 %). Four patients had dose-limiting toxicities of dermatitis acneiform, plus fatigue and pustular rash in one patient, and stomatitis in one patient. The maximum tolerated dose was 16 mg. Common drug-related AEs included dermatitis acneiform (51 %), diarrhea (29 %), and increased blood creatine phosphokinase (20 %); grade ≥ 3 AEs were reported in 27 (53 %) patients. Median Tmax was 3 h; systemic exposure increased less than dose-proportionally over the dose range 0.2-22 mg. On day 21 maximum inhibition of ERK phosphorylation in peripheral blood mononuclear cells of 46-97 % was seen in patients receiving TAK-733 ≥ 8.4 mg. Among 41 response-evaluable patients, 2 (5 %) patients with cutaneous melanoma (one with BRAF L597R mutant melanoma) had partial responses. Conclusions TAK-733 had a generally manageable toxicity profile up to the maximum tolerated dose, and showed the anticipated pharmacodynamic effect of sustained inhibition of ERK phosphorylation. Limited antitumor activity was demonstrated. Further investigation is not currently planned
Electrochemical etching of AlGaN for the realization of thin-film devices
Heterogeneously integrated AlGaN epitaxial layers will be essential for future optical and electrical devices like thin-film flip-chip ultraviolet (UV) light-emitting diodes, UV vertical-cavity surface-emitting lasers, and high-electron mobility transistors on efficient heat sinks. Such AlGaN-membranes will also enable flexible and micromechanical devices. However, to develop a method to separate the AlGaN-device membranes from the substrate has proven to be challenging, in particular, for high-quality device materials, which require the use of a lattice-matched AlGaN sacrificial layer. We demonstrate an electrochemical etching method by which it is possible to achieve complete lateral etching of an AlGaN sacrificial layer with up to 50% Al-content. The influence of etching voltage and the Al-content of the sacrificial layer on the etching process is investigated. The etched N-polar surface shows the same macroscopic topography as that of the as-grown epitaxial structure, and the root-mean square roughness is 3.5 nm for 1 \ub5m x 1 \ub5m scan areas. Separated device layers have a well-defined thickness and smooth etched surfaces. Transferred multi-quantum-well structures were fabricated and investigated by time-resolved photoluminescence measurements. The quantum wells showed no sign of degradation caused by the thin-film process
Microwave background anisotropies and non-linear structures II. Numerical computations
A new method for modelling spherically symmetric inhomogeneities is applied
to the formation of clusters in an expanding Universe. We impose simple initial
velocity and density perturbations of finite extent and we investigate the
subsequent evolution of the density field. Photon paths are also calculated,
allowing a detailed consideration of gravitational lensing effects and
microwave background anisotropies induced by the cluster. We apply the method
to modelling high-redshift clusters and, in particular, we consider the
reported microwave decrement observed towards the quasar pair PC1643+4631 A&B.
We also consider the effect on the primordial microwave background power
spectrum due to gravitational lensing by a population of massive high-redshift
clusters.Comment: 15 pages, 23 figures; Monthly Notices of the Royal Astronomical
Society (MNRAS), in pres
The harmonic power spectrum of the soft X-ray background I. The data analysis
Fluctuations of the soft X-ray background are investigated using harmonic
analysis. A section of the ROSAT All-Sky Survey around the north galactic pole
is used. The flux distribution is expanded into a set of harmonic functions and
the power spectrum is determined. Several subsamples of the RASS have been used
and the spectra for different regions and energies are presented. The effects
of the data binning in pixels are assessed and taken into account. The spectra
of the analyzed samples reflect both small scale effects generated by strong
discrete sources and the large scale gradients of the XRB distribution. Our
results show that the power spectrum technique can be effectively used to
investigate anisotropy of the XRB at various scales. This statistics will
become a useful tool in the investigation of various XRB components.Comment: 12 pages, A&A accepte
- …