1,329 research outputs found
Investigation of binary compounds using electron Rutherford backscattering
High-energy (40keV) electrons, scattering over large angles, transfer a small fraction of their kinetic energy to the target atoms, in the same way as ions do in Rutherford backscattering experiments. The authors show here that this energy transfer can be resolved and used to determine the mass of the scattering atom. In this way information on the surface composition for thicknesses of the order of 10nm can be obtained. The authors refer to this technique as “electron Rutherford backscattering.” In addition the peak width reveals unique information about the vibrational properties (mean kinetic energy) of the scattering atoms. Here the authors demonstrate that the method can be used to identify a number of technologically important compounds.This work is made possible by a grant of the
Australian Research Council
Electron spectroscopy using two-dimensional electron detection and a camera in a single electron counting mode
A brief description is given of an economical implementation of the read out of a two-dimensional detector in an electron spectrometer by a charge coupled device camera, using a pulse counting mode. Count rates up to 10 kHz can be handled in this way. A comparison with results obtained using a resistive anode detector is given for the case of electron scattering from Xe atoms. Good agreement was obtained between both detection techniques, establishing the validity of the method described here.This research was made possible by a grant of the Australian
Research Council
Systemic mastocytosis with associated myeloproliferative disease and precursor B lymphoblastic leukaemia with t(13;13)(q12;q22) involving FLT3.
Systemic mastocytoses represent neoplastic proliferations
of mast cells. In about 20% of cases systemic
mastocytoses are accompanied by clonal haematopoietic
non-mast cell-lineage disorders, most commonly myeloid
neoplasms. A case of systemic mastocytosis carrying the
characteristic mutation at codon 816 (D816V) in the KIT
gene of mast cells, with two concurrent accompanying
clonal haematopoietic non-mast cell-lineage disorders,
chronic myeloproliferative disease, unclassifiable and
precursor B lymphoblastic leukaemia is documented. Both
accompanying clonal haematopoietic non-mast cell-lineage
disorders carried the wild-type KIT gene, but had a
novel t(13;13)(q12;q22) involving the FLT3 locus at
13q12. The chronic myeloproliferative disease, unclassifiable
and the precursor B lymphoblastic leukaemia were
cured by syngenous stem cell transplantation, but the
systemic mastocytosis persisted for more than 10 years.
The additional impact of molecular techniques on the
correct diagnosis in haematological malignancies is
highlighted, and evidence is provided that, apart from
internal tandem duplications and mutations, FLT3 can be
activated by translocations
Electrical Control of Linear Dichroism in Black Phosphorus from the Visible to Mid-Infrared
The incorporation of electrically tunable materials into photonic structures
such as waveguides and metasurfaces enables dynamic control of light
propagation by an applied potential. While many materials have been shown to
exhibit electrically tunable permittivity and dispersion, including transparent
conducting oxides (TCOs) and III-V semiconductors and quantum wells, these
materials are all optically isotropic in the propagation plane. In this work,
we report the first known example of electrically tunable linear dichroism,
observed here in few-layer black phosphorus (BP), which is a promising
candidate for multi-functional, broadband, tunable photonic elements. We
measure active modulation of the linear dichroism from the mid-infrared to
visible frequency range, which is driven by anisotropic quantum-confined Stark
and Burstein-Moss effects, and field-induced forbidden-to-allowed optical
transitions. Moreover, we observe high BP absorption modulation strengths,
approaching unity for certain thicknesses and photon energies
Meningotheliomatöses Meningeom in einem reifen zystischen Teratom des Ovars
Zusammenfassung: Reife Teratome des Ovars zählen zu den Keimzelltumoren. Sie machen 27-44% aller Neoplasien des Ovars und bis zu 58% der benignen Ovarialtumoren aus. In reifen und unreifen Teratomen können sich sekundäre Tumoren der 3Keimblätter entwickeln. Diese können sowohl benigne als auch maligne sein. Wir berichten über den Fall eines meningotheliomatösen Meningeoms als Anteil eines reifen zystischen Teratoms bei einer 32-jährigen Patientin. Die typische Histomorphologie und die immunhistochemisch nachweisbare Expression von epithelialem Membranantigen (EMA) und Desmoplakin sind diagnostisch wegweisen
Is an intermediate state populated on the folding pathway of ubiquitin?
AbstractIn the last couple of years, there has been increasing debate as to the presence and role of intermediate states on the folding pathways of several small proteins, including the 76-residue protein ubiquitin. Here, we present detailed kinetic studies to establish whether an intermediate state is ever populated during the folding of this protein. We show that the differences observed in previous studies are attributable to the transient aggregation of the protein during folding. Using a highly soluble construct of ubiquitin, which does not aggregate during folding, we establish the conditions in which an intermediate state is sufficiently stable to be observed by kinetic measurements
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