1,148 research outputs found

    Ceramic nanostructure materials, membranes and composite layers

    Get PDF
    Synthesis methods to obtain nanoscale materials will be briefly discussed with a focus on sol-gel methods. Three types of nanoscale composites (powders, membranes and ion implanted layers) will be discussed and exemplified with recent original research results. Ceramic membranes with a thickness of 1–10 ÎŒm consist of a packing of elementary particles with a size of 3–7 nm. The mean pore size is about 2.5–3 nm. The preparation routes are based on sol and sol-gel technologies. The pores can be modified by liquid as well as by gas deposition techniques. This leads to modification of the chemical character and the effective pore size and gives rise to microstructure elements well below the size of the pores (3 nm). The modification of ceramic surface layers with a thickness of 0.05–0.5 ÎŒm by ion implantation and annealing procedures yields amorphous or strongly supersatured metastable solid solutions of e.g. Fe2O3 (or TiO2) in zirconia-yttria solid solutions or of very finely dispersed metal particles in the ceramic surface layers. Particle sizes are of the order of 2–4 nm. Both types of structures have interesting transport, catalytic and mechanical properties

    Multiplexed readout of kinetic inductance bolometer arrays

    Full text link
    Kinetic inductance bolometer (KIB) technology is a candidate for passive sub-millimeter wave and terahertz imaging systems. Its benefits include scalability into large 2D arrays and operation with intermediate cryogenics in the temperature range of 5 -- 10 K. We have previously demonstrated the scalability in terms of device fabrication, optics integration, and cryogenics. In this article, we address the last missing ingredient, the readout. The concept, serial addressed frequency excitation (SAFE), is an alternative to full frequency-division multiplexing at microwave frequencies conventionally used to read out kinetic inductance detectors. We introduce the concept, and analyze the criteria of the multiplexed readout avoiding the degradation of the signal-to-noise ratio in the presence of a thermal anti-alias filter inherent to thermal detectors. We present a practical scalable realization of a readout system integrated into a prototype imager with 8712 detectors. This is used for demonstrating the noise properties of the readout. Furthermore, we present practical detection experiments with a stand-off laboratory-scale imager.Comment: 7 pages, 6 figure

    First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of 163^{163}Ho

    Full text link
    The isotope 163^{163}Ho undergoes an electron capture process with a recommended value for the energy available to the decay, QECQ_{\rm EC}, of about 2.5 keV. According to the present knowledge, this is the lowest QECQ_{\rm EC} value for electron capture processes. Because of that, 163^{163}Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the 163^{163}Dy daughter atom upon the capture of an electron from the 5s shell in 163^{163}Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the 163^{163}Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of 163^{163}Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we discuss the implications of this result for the Electron Capture 163^{163}Ho experiment, ECHo, aiming to reach sub-eV sensitivity on the electron neutrino mass by a high precision and high statistics calorimetric measurement of the 163^{163}Ho spectrum.Comment: 5 pages, 3 figure

    First detection of [N II] 205 micrometer absorption in interstellar gas

    Get PDF
    We present high resolution [NII] 205 micrometer ^3P_1-^3P_0 spectra obtained with Herschel-HIFI towards a small sample of far-infrared bright star forming regions in the Galactic plane: W31C (G10.6-0.4), W49N (G43.2-0.1), W51 (G49.5-0.4), and G34.3+0.1. All sources display an emission line profile associated directly with the HII regions themselves. For the first time we also detect absorption of the [NII] 205 micrometer line by extended low-density foreground material towards W31C and W49N over a wide range of velocities. We attribute this absorption to the warm ionised medium (WIM) and find N(N^+)\approx 1.5x10^17 cm^-2 towards both sources. This is in agreement with recent Herschel-HIFI observations of [CII] 158 micrometer, also observed in absorption in the same sight-lines, if \approx7-10 % of all C^+ ions exist in the WIM on average. Using an abundance ratio of [N]/[H] = 6.76x10^-5 in the gas phase we find that the mean electron and proton volume densities are ~0.1-0.3 cm^-3 assuming a WIM volume filling fraction of 0.1-0.4 with a corresponding line-of-sight filling fraction of 0.46-0.74. A low density and a high WIM filling fraction are also supported by RADEX modelling of the [NII] 205 micrometer absorption and emission together with visible emission lines attributed mainly to the WIM. The detection of the 205 micrometer line in absorption emphasises the importance of a high spectral resolution, and also offers a new tool for investigation of the WIM.Comment: 7 pages, 4 figures, accepted for publication in Astronomy & Astrophysics, 11 June 201

    Differentiation of irradiation and cetuximab induced skin reactions in patients with locally advanced head and neck cancer undergoing radioimmunotherapy: the HICARE protocol (Head and neck cancer: ImmunoChemo and Radiotherapy with Erbitux) – a multicenter phase IV trial

    Get PDF
    BACKGROUND: In order to improve the clinical outcome of patients with locally advanced squamous cell carcinoma of the head and neck (LASCCHN) not being capable to receive platinum-based chemoradiation, radiotherapy can be intensified by addition of cetuximab, a monoclonal antibody that blocks the epidermal growth factor receptor (EGFR). The radioimmunotherapy with cetuximab is a feasible treatment option showing a favourable toxicity profile. The most frequent side effect of radiotherapy is radiation dermatitis, the most common side effect of treatment with cetuximab is acneiform rash. Incidence and severity of these frequent, often overlapping and sometimes limiting skin reactions, however, are not well explored. A clinical and molecular differentiation between radiogenic skin reactions and skin reactions caused by cetuximab which may correlate with outcome, have never been described before. METHODS/DESIGN: The HICARE study is a national, multicenter, prospective phase IV study exploring the different types of skin reactions that occur in patients with LASCCHN undergoing radioimmun(chemo)therapy with the EGFR inhibitor cetuximab. 500 patients with LASCCHN will be enrolled in 40 participating sites in Germany. Primary endpoint is the rate of radiation dermatitis NCI CTCAE grade 3 and 4 (v. 4.02). Radioimmunotherapy will be applied according to SmPC, i.e. cetuximab will be administered as loading dose and then weekly during the radiotherapy. Irradiation will be applied as intensity-modulated radiation therapy (IMRT) or 3D-dimensional radiation therapy. DISCUSSION: The HICARE trial is expected to be one of the largest trials ever conducted in head and neck cancer patients. The goal of the HICARE trial is to differentiate skin reactions caused by radiation from those caused by the monoclonal antibody cetuximab, to evaluate the incidence and severity of these skin reactions and to correlate them with outcome parameters. Besides, the translational research program will help to identify and confirm novel peripheral blood based molecular predictors and surrogates for treatment response and resistance. TRIAL REGISTRATION: Clinical Trial Identifier, NCT01553032 (clinicaltrials.gov) EudraCT number: 2010-019748-3

    The chemistry of C3 & Carbon Chain Molecules in DR21(OH)

    Get PDF
    (Abridged) We have observed velocity resolved spectra of four ro-vibrational far-infrared transitions of C3 between the vibrational ground state and the low-energy nu2 bending mode at frequencies between 1654--1897 GHz using HIFI on board Herschel, in DR21(OH), a high mass star forming region. Several transitions of CCH and c-C3H2 have also been observed with HIFI and the IRAM 30m telescope. A gas and grain warm-up model was used to identify the primary C3 forming reactions in DR21(OH). We have detected C3 in absorption in four far-infrared transitions, P(4), P(10), Q(2) and Q(4). The continuum sources MM1 and MM2 in DR21(OH) though spatially unresolved, are sufficiently separated in velocity to be identified in the C3 spectra. All C3 transitions are detected from the embedded source MM2 and the surrounding envelope, whereas only Q(4) & P(4) are detected toward the hot core MM1. The abundance of C3 in the envelope and MM2 is \sim6x10^{-10} and \sim3x10^{-9} respectively. For CCH and c-C3H2 we only detect emission from the envelope and MM1. The observed CCH, C3, and c-C3H2 abundances are most consistent with a chemical model with n(H2)\sim5x10^{6} cm^-3 post-warm-up dust temperature, T_max =30 K and a time of \sim0.7-3 Myr. Post warm-up gas phase chemistry of CH4 released from the grain at t\sim 0.2 Myr and lasting for 1 Myr can explain the observed C3 abundance in the envelope of DR21(OH) and no mechanism involving photodestruction of PAH molecules is required. The chemistry in the envelope is similar to the warm carbon chain chemistry (WCCC) found in lukewarm corinos. The observed lower C3 abundance in MM1 as compared to MM2 and the envelope could be indicative of destruction of C3 in the more evolved MM1. The timescale for the chemistry derived for the envelope is consistent with the dynamical timescale of 2 Myr derived for DR21(OH) in other studies.Comment: 11 Pages, 6 figures, accepted for publication in A&

    Characterization of the 163^{163}Ho Electron Capture Spectrum: A Step Towards the Electron Neutrino Mass Determination

    Get PDF
    The isotope 163^{163}Ho is in many ways the best candidate to perform experiments to investigate the value of the electron neutrino mass. It undergoes an electron capture process to 163^{163}Dy with an energy available to the decay, QEC_{EC}, of about 2.8 keV. According to the present knowledge, this is the lowest QEC_{EC} value for such transitions. Here we discuss a newly obtained spectrum of 163^{163}Ho, taken by cryogenic metallic magnetic calorimeters with 163^{163}Ho implanted in the absorbers and operated in anticoincident mode for background reduction. For the first time, the atomic deexcitation of the 163^{163}Dy daughter atom following the capture of electrons from the 5s shell in 163^{163}Ho, the OI line, was observed with a calorimetric measurement. The peak energy is determined to be 48 eV. In addition, a precise determination of the energy available for the decay QEC_{EC}=(2.858±0.010stat_{stat}±0.05syst_{syst})  keV was obtained by analyzing the intensities of the lines in the spectrum. This value is in good agreement with the measurement of the mass difference between 163^{163}Ho and 163^{163}Dy obtained by Penning-trap mass spectrometry, demonstrating the reliability of the calorimetric technique

    Right orbitofrontal corticolimbic and left corticocortical white matter connectivity differentiate bipolar and unipolar depression

    Get PDF
    Objectives - The absence of pathophysiologically relevant diagnostic markers of bipolar disorder (BD) leads to its frequent misdiagnosis as unipolar depression (UD). We aimed to determine whether whole brain white matter connectivity differentiated BD from UD depression. Methods - We employed a three-way analysis of covariance, covarying for age, to examine whole brain fractional anisotropy (FA), and corresponding longitudinal and radial diffusivity, in currently depressed adults: 15 with BD-type I (mean age 36.3 years, SD 12.0 years), 16 with recurrent UD (mean age 32.3 years, SD 10.0 years), and 24 healthy control adults (HC) (mean age 29.5 years, SD 9.43 years). Depressed groups did not differ in depression severity, age of illness onset, and illness duration. Results - There was a main effect of group in left superior and inferior longitudinal fasciculi (SLF and ILF) (all F = 9.8; p = .05, corrected). Whole brain post hoc analyses (all t = 4.2; p = .05, corrected) revealed decreased FA in left SLF in BD, versus UD adults in inferior temporal cortex and, versus HC, in primary sensory cortex (associated with increased radial and decreased longitudinal diffusivity, respectively); and decreased FA in left ILF in UD adults versus HC. A main effect of group in right uncinate fasciculus (in orbitofrontal cortex) just failed to meet significance in all participants but was present in women. Post hoc analyses revealed decreased right uncinate fasciculus FA in all and in women, BD versus HC. Conclusions - White matter FA in left occipitotemporal and primary sensory regions supporting visuospatial and sensory processing differentiates BD from UD depression. Abnormally reduced FA in right fronto-temporal regions supporting mood regulation, might underlie predisposition to depression in BD. These measures might help differentiate pathophysiologic processes of BD versus UD depression
    • 

    corecore