Search results for "RADIATION"
showing 10 items of 5298 documents
Photo fragmentation of metal clusters stored in a penning trap
1996
Photo fragmentation studies of stored mass selected metal cluster ions of a large size range are reported. The experimental method and the data evaluation are described in detail. Gold cluster ions were produced by laser vaporization and stored in a Penning trap. After size selection they were electronically excited by irradiation with a pulsed laser beam. Relaxation by evaporation of neutral atoms and dimers was observed as a function of photon energy. From these data upper and lower limits for dissociation energies are determined for Aun + (n=3 to 23).
Electron impact ionization/dissociation of size selected gold cluster cations
2000
Abstract Singly charged gold clusters, Au n + in the size range n =12 to 72 have been captured and stored in a Penning trap, size selected and subjected to an electron beam. This interaction leads to further ionization as well as dissociation. The resulting abundance spectra of doubly and triply charged clusters show (a) a lower size limit for the production of multiply charged clusters from an ensemble of hot precursors, which can be understood in terms of the respective decay pathways, (b) an odd/even alternation of singly and doubly charged clusters in the size range below n =30, which inverses sign with change of charge state, and (c) magic numbers, i.e. prominent signals for particular…
A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo
2021
This paper presents the gravitational-wave measurement of the Hubble constant (H 0) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of H 0. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is H 0 = km s-1 Mpc-1 (68.3% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 (about 4%) over the GW170817-only value of km s-1 Mpc-1. A significant …
First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data
2017
Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, {\it narrow-band} analyses methods have been developed, allowing a fully coherent search for gravitational waves from known …
Boosting the methanolysis of polycarbonate by the synergy between ultrasound irradiation and task specific ionic liquids
2021
In an attempt to perform polycarbonate chemical recycling in a more sustainable way, we took into consideration the combined use of ultrasound irradiation and task specific ionic liquids. Towards this aim, the methanolysis of polycarbonate, into dimethylcarbonate and bisphenol A, was carried out in the presence of cholinium-based ionic liquids featuring anions derived from amino acids and other eco-friendly species. The target process was optimized in terms of both energy and material amounts as well as in terms of the nature of the catalysts used. The proposed protocol allowed high conversion and yields of bisphenol A to be obtained, under milder conditions compared to the ones so far repo…
The influence of ozone and aerosols on the experimental values of UV erythemal radiation at ground level in Valencia
2009
Ultraviolet erythemal radiation (UVER) values have been simulated for different values of column ozone and aerosol optical depth (AOD) using a multiple scattering model: SBDART. The results show that UVER decreased when atmospheric ozone and aerosols increased, with the ozone having greater influence than AOD. To quantify these dependencies the influence of aerosols on the simulated values of UVER has been analysed for different ozone values. This dependence was linear. Similarly, to quantify the influence of ozone on the UVER values this was simulated for fixed values of AOD while varying the column ozone. The expression of this dependence was found to be a second-order polynomial. We also…
Intra- and extra-cellular DNA damage by harmine and 9-methyl-harmine
2014
It is known that b-carbolines are able to produce photosensitized damage in cell-free DNA, but there is little information on their effects on cellular DNA. Therefore, we have analyzed the DNA damage produced by harmine and 9-methyl-harmine under UVA irradiation in V79 cells, together with the associated generation of micronuclei and photocytotoxicity. The results indicate that the most frequent photoproducts generated in the cellular DNA are modified purines such as 8-oxo-7,8-dihydroguanine. Only relatively few single-strand breaks were observed. CPDs were absent, although they were generated in cell-free DNA irradiated under the same conditions. The overall extent of DNA damage in the cel…
Abstract CT020: MERIT: introducing individualized cancer vaccines for the treatment of TNBC - a phase I trial
2016
Abstract The majority of metastatic cancers remain incurable since the current methods of treatment often fail to target the heterogeneous nature of each individual patient's tumor. Personalized approaches targeting each individual patient's tumor may therefore bring significant improvements. The Mutanome Engineered RNA Immuno-Therapy (MERIT) consortium will clinically validate a pioneering RNA-based immunotherapy concept for the treatment of triple negative breast cancer (TNBC) by targeting shared tumor antigens and individual neo-antigens in TNBC patients. MERIT combines two personalized treatment concepts: (i) treatment with vaccines containing “off-the-shelf” mRNAs selected from a pre-s…
Absolutzählung von radionukliden durch die beta-gamma-koinzidenzmethode mit einem flüssigen szintillator als innerem beta-detektor
1965
Zusammenfassung Fehlerquellen und Genauigkeit der Methode wurden untersucht. Die Ortsabhangigkeit der Zahlausbeuten im β- und γ-Detektor bedingt trotz des grossen Probenvolumens keinen wesentlichen Fehler, wenn die Detektoren symmetrisch angeordnet sind. Dagegen mussen Fehler korrigiert werden, die durch unvollkommenen Nachweis energiearmer Zerfallszweige im β-Detector und durch die γ-Empfindlichkeit des β-Detektors entstehen; dies kann entweder durch graphische Extrapolation oder—allgemeiner—durch Berechnen eines Korrekturfaktors geschehen. Die rechnerische Korrektur wird an typischen Zerfallsschemata erlautert. Fur den statistischen Fehler der Zerfallsrate wird eine Formel angegeben, welc…
Erfassung und auswertung hämodynamicscher funktionsabläufe mit dem neuen I2-kanalfunktionsmeβstand “Mainz”
1970
Zusammenfassung Mit dem 12-Kanalfunktionsmeβstand “Mainz” konnen hamodynamische Funktionsmessungen an 6 verschiedenen Stellen der Korperoberflache vollsimultan durchgefuhrt werden. Die digital gespeicherten Aktivitatsverlaufe werden mit geeigneten Mittelungsverfahren geglattet und die auftretenden Ratenkonstanten, nach halblogarithmischer, analoger Ausgabe, graphisch ermittelt. Komplementare Exponentialverlaufe werden elektronisch differenziert, halblogarithmisch ausgeschrieben und bezuglich der gesuchten Ratenkonstanten wiederum graphisch ausgewertet. Anhand ausgewahlter Beispiele wird gezeigt, wie die registrierten Aktivitatsverlaufe zerlegt und uber geeignete, mathematisch formulierte Mo…