418 research outputs found
Bedeutung molekularpathologischer Methoden in der Onkologie: Pathologie und onkologische Entscheidungsprozesse
Zusammenfassung: Die Anzahl von molekularen Untersuchungen in der Histo- und Zytopathologie hat in den letzten Jahren, insbesondere mit zunehmender Bedeutung der sog. personalisierten Medizin bei Krebspatienten, stark zugenommen. Die Ergebnisse dieser Untersuchungen fließen vermehrt in die Pathologieberichte ein, die den behandelnden Ärzten als Grundlage für weitere Therapieentscheidungen dienen. Die wichtigsten molekularen Methoden, die derzeit in der Pathologie eingesetzt werden, werden mit ihren Möglichkeiten und Grenzen vorgestell
Bedeutung molekularpathologischer Methoden in der Onkologie: Pathologie und onkologische Entscheidungsprozesse
Zusammenfassung: Die Anzahl von molekularen Untersuchungen in der Histo- und Zytopathologie hat in den letzten Jahren, insbesondere mit zunehmender Bedeutung der sog. personalisierten Medizin bei Krebspatienten, stark zugenommen. Die Ergebnisse dieser Untersuchungen fließen vermehrt in die Pathologieberichte ein, die den behandelnden Ärzten als Grundlage für weitere Therapieentscheidungen dienen. Die wichtigsten molekularen Methoden, die derzeit in der Pathologie eingesetzt werden, werden mit ihren Möglichkeiten und Grenzen vorgestell
Evidence for multiple superconducting gaps in optimally doped BaFeCoAs from infrared spectroscopy
We performed combined infrared reflection and ellipsometry measurements of
the in-plane optical reponse of single crystals of the pnictide high
temperature superconductor BaFeCoAs with = 24.5
K. We observed characteristic superconductivity-induced changes which provide
evidence for at least three different energy gaps. We show that a BCS-model of
isotropic gaps with 2 of 3.1, 4.7, and 9.2 reproduces the
experimental data rather well. We also determine the low-temperature value of
the in-plane magnetic penetration depth of 270 nm
Recurrent phosphaturic mesenchymal tumour of the temporal bone causing deafness and facial nerve palsy
Abstract Objective: We describe the first reported case of a phosphaturic mesenchymal tumour, mixed connective tissue variant, invading the temporal bone. Case report: A female patient presented with increasing deafness. On examination there appeared to be a mass behind an intact tympanic membrane. Further radiological investigation showed a vascular mass occupying the middle ear, mastoid and internal auditory meatus. This was surgically resected and revealed to be a benign phosphaturic mesenchymal tumour, mixed connective tissue variant. The tumour recurred a year later, presenting as facial nerve palsy. A revision procedure was carried out; the tumour was excised with the sacrifice of a segment of the facial nerve, and a facial-hypoglossal nerve anastomosis was performed. Conclusion: This case report highlights the occurrence of this benign but sometimes aggressive tumour, of which both clinicians and pathologists should be aware. Early recognition of the condition remains of utmost importance to minimise the debilitating consequences of long-term osteomalacia in affected patients, and to prevent extracranial and intracranial complications caused by the tumou
LRRML: a conformational database and an XML description of leucine-rich repeats (LRRs)
Background: Leucine-rich repeats (LRRs) are present in more than 6000 proteins. They are found in organisms ranging from viruses to eukaryotes and play an important role in protein-ligand interactions. To date, more than one hundred crystal structures of LRR containing proteins have been determined. This knowledge has increased our ability to use the crystal structures as templates to model LRR proteins with unknown structures. Since the individual three-dimensional LRR structures are not directly available from the established databases and since there are only a few detailed annotations for them, a conformational LRR database useful for homology modeling of LRR proteins is desirable. Description: We developed LRRML, a conformational database and an extensible markup language (XML) description of LRRs. The release 0.2 contains 1261 individual LRR structures, which were identified from 112 PDB structures and annotated manually. An XML structure was defined to exchange and store the LRRs. LRRML provides a source for homology modeling and structural analysis of LRR proteins. In order to demonstrate the capabilities of the database we modeled the mouse Toll-like receptor 3 (TLR3) by multiple templates homology modeling and compared the result with the crystal structure. Conclusion: LRRML is an information source for investigators involved in both theoretical and applied research on LRR proteins. It is available at http://zeus.krist.geo.uni-muenchen.de/similar to lrrml
Macroscopic phase segregation in superconducting K0.73Fe1.67Se2 as seen by muon spin rotation and infrared spectroscopy
Using muon spin rotation (\muSR) and infrared spectroscopy we investigated
the recently discovered superconductor K0.73Fe1.67Se2 with Tc = 32 K. We show
that the combined data can be consistently described in terms of a
macroscopically phase segregated state with a matrix of ~88% volume fraction
that is insulating and strongly magnetic and inclusions with a ~12% volume
fraction which are metallic, superconducting and non-magnetic. The electronic
properties of the latter, in terms of the normal state plasma frequency and the
superconducting condensate density, appear to be similar as in other iron
selenide or arsenide superconductors.Comment: 22 pages, 8 figures. (citation list correction.
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Reciprocal space slicing: A time-efficient approach to femtosecond x-ray diffraction
An experimental technique that allows faster assessment of out-of-plane strain dynamics of thin film heterostructures via x-ray diffraction is presented. In contrast to conventional high-speed reciprocal space-mapping setups, our approach reduces the measurement time drastically due to a fixed measurement geometry with a position-sensitive detector. This means that neither the incident (ω) nor the exit ( 2θ ) diffraction angle is scanned during the strain assessment via x-ray diffraction. Shifts of diffraction peaks on the fixed x-ray area detector originate from an out-of-plane strain within the sample. Quantitative strain assessment requires the determination of a factor relating the observed shift to the change in the reciprocal lattice vector. The factor depends only on the widths of the peak along certain directions in reciprocal space, the diffraction angle of the studied reflection, and the resolution of the instrumental setup. We provide a full theoretical explanation and exemplify the concept with picosecond strain dynamics of a thin layer of NbO2
Electric-field-induced pyroelectric order and localization of the confined electrons in LaAlO3/SrTiO3 heterostructures
With infrared ellipsometry, x-ray diffraction, and electric transport
measurements we investigated the electric-field-effect on the confined
electrons at the LaAlO3/SrTiO3 interface. We obtained evidence that the
localization of the electrons at low temperature and negative gate voltage is
induced, or at least strongly enhanced, by a pyroelectric phase transition in
SrTiO3 which strongly reduces the lattice polarizability and the subsequent
Coulomb screening. In particular, we show that the charge localisation and the
polar order of SrTiO3 both develop below about 50 K and exhibit similar,
unipolar hysteresis loops as a function of the gate voltage. Our findings
suggest that the pyroelectric order also plays an important role in the quantum
phase transition at very low temperatures where superconductivity is suppressed
by an electric field.Comment: 5 pages, 4 figures, supplementary materia
Pseudogap and precursor superconductivity in underdoped cuprate high temperature superconductors: A far-infrared ellipsometry study
Abstract.: With the technique of infrared ellipsometry we performed a detailed study of the temperature- and doping dependence of the c-axis response of a series of YBa2Cu3O7−δ single crystals. In particular, we explored the anomalous electronic properties at temperatures above the macroscopic superconducting transition temperature, T c, whose conflicting explanations range from a precursor superconducting state to electronic correlations that compete with superconductivity. We show that the c-axis spectra provide evidence that both kinds of correlations are present and that their contributions can be disentangled based on an analysis with a so-called multilayer-model. We find that the onset temperature, T *, and the energy scale, ΔPG, of the competing pseudogap increase rapidly towards the underdoped side whereas they vanish on the overdoped side. In addition, we provide evidence that in a strongly underdoped sample the precursor superconducting correlations develop below an onset temperature, T ons, that is considerably lower than T * but still much higher than T
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