836 research outputs found
Modelling line emission of deuterated H_3^+ from prestellar cores
Context: The depletion of heavy elements in cold cores of interstellar
molecular clouds can lead to a situation where deuterated forms of H_3^+ are
the most useful spectroscopic probes of the physical conditions.
Aims: The aim is to predict the observability of the rotational lines of
H_2D^+ and D_2H^+ from prestellar cores.
Methods: Recently derived rate coefficients for the H_3^+ + H_2 isotopic
system were applied to the "complete depletion" reaction scheme to calculate
abundance profiles in hydrostatic core models. The ground-state lines of
H_2D^+(o) (372 GHz) and D_2H^+(p) (692 GHz) arising from these cores were
simulated. The excitation of the rotational levels of these molecules was
approximated by using the state-to-state coefficients for collisions with H_2.
We also predicted line profiles from cores with a power-law density
distribution advocated in some previous studies.
Results: The new rate coefficients introduce some changes to the complete
depletion model, but do not alter the general tendencies. One of the
modifications with respect to the previous results is the increase of the D_3^+
abundance at the cost of other isotopologues. Furthermore, the present model
predicts a lower H_2D^+ (o/p) ratio, and a slightly higher D_2H^+ (p/o) ratio
in very cold, dense cores, as compared with previous modelling results. These
nuclear spin ratios affect the detectability of the submm lines of H_2D^+(o)
and D_2H^+(p). The previously detected H_2D^+ and D_2H^+ lines towards the core
I16293E, and the H_2D^+ line observed towards Oph D can be reproduced using the
present excitation model and the physical models suggested in the original
papers.Comment: 10 pages, 11 Figures; ver2: updated some of the Figures, added some
references, added an entry to acknowledgement
Activity and side effects of imatinib in patients with gastrointestinal stromal tumors: data from a german multicenter trial
Gastrointestinal stromal tumors (GIST) are mesenchymal tumors that in the past were classified as leiomyosarcomas or leiomyomas not responding to standard sarcoma chemotherapy. In several phase I and II trials the efficacy and safety of imatinib was shown before the largest trial ever performed in a single sarcoma entity revealed response rates (CR/PR) of 52%. This multicenter phase II trial presented here was performed to open access to imatinib for patients with unresectable or metastastatic GIST when the EORTC 62005 trial had been closed before imatinib was approved in Germany. It was designed to follow the best clinical response and to assess the efficacy, safety and tolerability of imatinib 400 mg/d in patients with unresectable or metastatic gastrointestinal stromal tumor
Rotational spectroscopy of mono-deuterated oxirane (-CHDO) and its detection towards IRAS 162932422 B
We prepared a sample of mono-deuterated oxirane and studied its rotational
spectrum in the laboratory between 490 GHz and 1060 GHz in order to improve its
spectroscopic parameters and consequently the calculated rest frequencies of
its rotational transitions. The updated rest frequencies were employed to
detect -CHDO for the first time in the interstellar medium in the
Atacama Large Millimetre/submillimetre Array (ALMA) Protostellar
Interferometric Line Survey (PILS) of the Class 0 protostellar system IRAS
162932422. Fits of the detected lines using the rotation diagrams yield a
temperature of K, which in turn agrees well with 125
K derived for the -CHO main isotopologue previously. The
-CHDO to -CHO ratio is found to be 0.15
corresponding to a D-to-H ratio of 0.036 per H atom which is slightly
higher than the D-to-H ratio of species such as methanol, formaldehyde, ketene
and but lower than those of the larger complex organic species such as ethanol,
methylformate and glycolaldehyde. This may reflect that oxirane is formed
fairly early in the evolution of the prestellar cores. The identification of
doubly deuterated oxirane isotopomers in the PILS data may be possible judged
by the amount of mono-deuterated oxirane and the observed trend that multiply
deuterated isotopologues have higher deuteration rates than their
mono-deuterated variants.Comment: 10 pages total; Mon. Not. R. Astron. Soc., accepte
Rotational spectroscopy of the thioformaldehyde isotopologues HCS and HCS in four interacting excited vibrational states and an account on the rotational spectrum of thioketene, HCCS
An investigation of the rotational spectrum of the interstellar molecule
thioformaldehyde between 110 and 377 GHz through a pyrolysis reaction revealed
a multitude of absorption lines assignable to HCS and HCS in
their lowest four excited vibrational states besides lines of numerous
thioformaldehyde isotopologues in their ground vibrational states reported
earlier as well as lines pertaining to several by-products. Additional
transitions of HCS in its lowest four excited vibrational states were
recorded in selected regions between 571 and 1386 GHz. Slight to strong
Coriolis interactions occur between all four vibrational states with the
exception of the two highest lying states because both are totally symmetric
vibrations. We present combined analyses of the ground and the four interacting
states for our rotational data of HCS and HCS. The HCS data
were supplemented with two sets of high-resultion IR data in two separate
analyses. The state has been included in analyses of Coriolis
interactions of low-lying fundamental states of HCS for the first time and
this improved the quality of the fits substantially. We extended furthermore
assignments in of transition frequencies of thioketene in its ground
vibrational state.Comment: 23 pages including figures, tables, and references; Mol. Phys.,
accepted (for the Tim Lee memorial issue
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