2,889 research outputs found

    Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)

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    The discovery of amino acids in meteorites and the detection of glycine in samples returned from a comet to Earth suggest that the interstellar chemistry is capable of producing such complex organic molecules. Our goal is to investigate the degree of chemical complexity that can be reached in the ISM. We performed an unbiased, spectral line survey toward Sgr B2(N) and (M) with the IRAM 30m telescope in the 3mm window. The spectra were analyzed with a simple radiative transfer model that assumes LTE but takes optical depth effects into account. About 3675 and 945 spectral lines with a peak signal-to-noise ratio higher than 4 are detected toward N and M, i.e. about 102 and 26 lines per GHz, respectively. This represents an increase by about a factor of 2 over previous surveys of Sgr B2. About 70% and 47% of the lines detected toward N and M are identified and assigned to 56 and 46 distinct molecules as well as to 66 and 54 less abundant isotopologues of these molecules, respectively. We also report the detection of transitions from 59 and 24 catalog entries corresponding to vibrationally or torsionally excited states of some of these molecules, respectively. Excitation temperatures and column densities were derived for each species but should be used with caution. Among the detected molecules, aminoacetonitrile, n-propyl cyanide, and ethyl formate were reported for the first time in space based on this survey, as were 5 rare isotopologues of vinyl cyanide, cyanoacetylene, and hydrogen cyanide. We also report the detection of transitions from within 12 new vib. or tors. excited states of known molecules. Although the large number of unidentified lines may still allow future identification of new molecules, we expect most of these lines to belong to vib. or tors. excited states or to rare isotopologues of known molecules for which spectroscopic predictions are currently missing. (abridged)Comment: Accepted for publication in A&A. 266 pages (39 pages of text), 111 tables, 8 figure

    Squamous Cell Carcinoma of the Larynx Arising in Multifocal Pharyngolaryngeal Oncocytic Papillary Cystadenoma:A Case Report and Review of the Literature

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    We report on a rare case of a laryngeal carcinoma arising in a multifocal pharyngolaryngeal oncocytic papillary cystadenoma (OPC). The disease of a 63-year-old man is well documented by computed and positron emission tomography, histology, and electron microscopy. We could show that an OPC can even develop in the pharynx. The coexistence of both tumors makes this a challenging diagnosis for pathologists. Treated by surgery and radiotherapy, both lesions dissolved. Based on the literature available, we discuss the theory that the laryngeal carcinoma might be the result of a true metaplasia facilitated by chronic irritation and recommend a regular follow-up for OPC too. As in benign oncocytic lesions, we could show that the detection of numerous mitochondria is a diagnostic indicator for malignant variants as well

    Macrophage and Galleria mellonella infection models reflect the virulence of naturally occurring isolates of B. pseudomallei, B. thailandensis and B. oklahomensis

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    addresses: Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, UK.notes: PMCID: PMC3025829types: Journal Article; Research Support, Non-U.S. Gov't© 2011 Wand et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Burkholderia pseudomallei is the causative agent of melioidosis, a tropical disease of humans with a variable and often fatal outcome. In murine models of infection, different strains exhibit varying degrees of virulence. In contrast, two related species, B. thailandensis and B. oklahomensis, are highly attenuated in mice. Our aim was to determine whether virulence in mice is reflected in macrophage or wax moth larvae (Galleria mellonella) infection models

    Telemedical Support in Patients with Chronic Heart Failure: Experience from Different Projects in Germany

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    The great epidemiological significance and costs associated with chronic heart failure pose a challenge to health systems in Western industrial countries. In the past few years, controlled randomised studies have shown that patients with chronic heart failure benefit from telemedical monitoring; specifically, telemonitoring of various vital parameters combined with a review of the symptoms, drug compliance and patient education. In Germany, various telemedical monitoring projects for patients with chronic heart failure have been initiated in the past few years; seven of them are presented here. Currently 7220 patients are being monitored in the seven selected projects. Most patients (51.1%) are in NYHA stage II, 26.3% in NYHA stage III, 14.5% in NYHA stage I and only 6.6% in NYHA stage IV respectively. Most projects are primarily regional. Their structure of telemedical monitoring tends to be modular and uses stratification according to the NYHA stages. All projects include medical or health economics assessments. The future of telemedical monitoring projects for patients with chronic heart failure will depend on the outcome of these assessments. Only of there is statistical evidence for medical benefit to the individual patient as well as cost savings will these projects continue

    Electrical control of inter-dot electron tunneling in a quantum dot molecule

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    We employ ultrafast pump-probe spectroscopy to directly monitor electron tunneling between discrete orbital states in a pair of spatially separated quantum dots. Immediately after excitation, several peaks are observed in the pump-probe spectrum due to Coulomb interactions between the photo-generated charge carriers. By tuning the relative energy of the orbital states in the two dots and monitoring the temporal evolution of the pump-probe spectra the electron and hole tunneling times are separately measured and resonant tunneling between the two dots is shown to be mediated both by elastic and inelastic processes. Ultrafast (< 5 ps) inter-dot tunneling is shown to occur over a surprisingly wide bandwidth, up to ~8 meV, reflecting the spectrum of exciton-acoustic phonon coupling in the system

    Diffusion-weighted imaging in oral squamous cell carcinoma using 3 Tesla MRI: is there a chance for preoperative discrimination between benign and malignant lymph nodes in daily clinical routine?

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    Background Preoperative staging of cervical lymph nodes is important to determine the extent of neck dissection in patients with oral squamous cell carcinoma (OSCC). Purpose To evaluate whether a preoperative discrimination of benign and malignant cervical lymph nodes with diffusion-weighted imaging (DWI) (3T) is feasible for clinical application. Material and Methods Forty-five patients with histological proven OSCC underwent preoperative 3T-MRI. DWI (b=0, 500, and 1000s/mm(2)) was added to the standard magnetic resonance imaging (MRI) protocol. Mean apparent diffusion coefficients (ADC(mean)) were measured for lymph nodes with 3mm or more in short axis by two independent readers. Finally, these results were matched with histology. Results Mean ADC was significantly higher for malignant than for benign nodes (1.1430.188 * 10(-3) mm(2)/s vs. 0.987 +/- 0.215 * 10(-3) mm(2)/s). Using an ADC value of 0.994 * 10(-3) mm(2)/s as threshold results in a sensitivity of 80%, specificity of 65%, positive predictive value of 31%, and negative predictive value of 93%. Conclusion Due to a limited sensitivity and specificity DWI alone is not suitable to reliably discriminate benign from malignant cervical lymph nodes in daily clinical routine. Hence, the preoperative determination of the extent of neck dissection on the basis of ADC measurements is not meaningful

    Opioid-blunted cortisol response to stress is associated with increased negative mood and wanting of social reward

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    Animal research suggests a central role of the μ-opioid receptor (MOR) system in regulating affiliative behaviors and in mediating the stress-buffering function of social contact. However, the neurochemistry of stress-related social contact seeking in humans is still poorly understood. In a randomized, double-blind, between-subjects design, healthy female volunteers (N = 80) received either 10 mg of the µ-opioid agonist morphine sulfate, or a placebo. Following a standardized psychosocial stress induction, participants engaged in a social reward task, in which the motivation to obtain skin-to-skin social touch and the hedonic reactions elicited by such touch were assessed. Morphine prevented the increase of salivary cortisol typically observed following acute stress exposure. Notably, this altered HPA axis responsivity was associated with increased negative affect in response to psychosocial stress, and with enhanced subjective wanting of highly rewarding social contact. These findings provide novel evidence on the effect of exogenous opioids administration on the reactions to psychosocial stress and point to a state-dependent regulation of social motivation

    Rotational spectroscopy of isotopic vinyl cyanide, H2_2C=CH-C\equivN, in the laboratory and in space

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    The rotational spectra of singly substituted 13^{13}C and 15^{15}N isotopic species of vinyl cyanide have been studied in natural abundances between 64 and 351 GHz. In combination with previous results, greatly improved spectroscopic parameters have been obtained which in turn helped to identify transitions of the 13^{13}C species for the first time in space through a molecular line survey of the extremely line-rich interstellar source Sagittarius B2(N) in the 3 mm region with some additional observations at 2 mm. The 13^{13}C species are detected in two compact (2.3\sim 2.3''), hot (170 K) cores with a column density of 3.8×1016\sim 3.8 \times 10^{16} and 1.1×10161.1 \times 10^{16} cm2^{-2}, respectively. In the main source, the so-called ``Large Molecule Heimat'', we derive an abundance of 2.9×1092.9 \times 10^{-9} for each 13^{13}C species relative to H2_2. An isotopic ratio 12^{12}C/13^{13}C of 21 has been measured. Based on a comparison to the column densities measured for the 13^{13}C species of ethyl cyanide also detected in this survey, it is suggested that the two hot cores of Sgr B2(N) are in different evolutionary stages. Supplementary laboratory data for the main isotopic species recorded between 92 and 342 GHz permitted an improvement of its spectroscopic parameters as well.Comment: 18 pages, including 2 tables, 3 figures; plus one supplementary text file plus one supplementary pdf file; J. Mol. Spectrosc., in press (to appear in the July or August issue of 2008
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