813 research outputs found

    Progress on the Super-FRS Experimental Program

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    Pygmy Dipol Resonances as a Manifestation of the Structure of the Neutron-Rich Nuclei

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    Dipole excitations in neutron-rich nuclei below the neutron threshold are investigated. The method is based on Hartree-Fock-Bogoliubov (HFB) and Quasiparticle-Phonon Model (QPM) theory. Of our special interest are the properties of the low-lying 1- Pygmy Resonance and the two-phonon quadrupole-octupole 1- states in Sn-isotopes including exploratory investigations for the experimentally unknown mass regions. In particular we investigate the evolution of the dipole strength function with the neutron excess. The use of HFB mean-field potentials and s.p. energies is found to provide a reliable extrapolation into the region off stability.Comment: 8 pages, 3 figures, Proceedings of the International Conference on Collective Motion in Nuclei Under Extreme Conditions (COMEX1), Paris, France, 10-13 June 200

    Tetracyclic thioxanthene derivatives: Studies on fluorescence and antitumor activity

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    Thioxanthones are bioisosteres of the naturally occurring xanthones. They have been described for multiple activities, including antitumor. As such, the synthesis of a library of thioxanthones was pursued, but unexpectedly, four tetracyclic thioxanthenes with a quinazoline– chromene scaffold were obtained. These compounds were studied for their human tumor cell growth inhibition activity, in the cell lines A375-C5, MCF-7 and NCI-H460. Photophysical studies were also performed. Two of the compounds displayed GI50 values below 10 ”M for the three tested cell lines, and structure–activity relationship studies were established. Three compounds presented similar wavelengths of absorption and emission, characteristic of dyes with a push-pull character. The structures of two compounds were elucidated by X-ray crystallography. Two tetracyclic thioxanthenes emerged as hit compounds. One of the two compounds accumulated intracellularly as a bright fluorescent dye in the green channel, as analyzed by both fluorescence microscopy and flow cytometry, making it a promising theranostic cancer drug candidate.This research was partially supported by the Strategic Funding UIDB/04423/2020, UIDP/04423/2020 (Group of Natural Products and Medicinal Chemistry‐CIIMAR) and under the project PTDC/SAU‐PUB/28736/2017 (reference POCI‐01‐0145‐FEDER‐028736), co‐financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF and by FCT through national funds. Fernando DurĂŁes acknowledges his FCT grant (SFRH/BD/144681/2019). Hassan Bousbaa acknowledges funding from CESPU (IMPLDEBRIS‐PL‐3RL‐IINFACTS‐2019). This research was funded by Fundação para a CiĂȘncia e a Tecnologia (FCT) through research units UIDB/50006/2020, UID/CTM/50011/2019, UIDB/50011/2020 & UIDP/50011/2020 and by the European Union (FEDER program) through project CENTRO‐01‐0145‐FEDER‐000003

    Susceptibility testing and reporting of new antibiotics with a focus on tedizolid: an international working group report

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    Inappropriate use and overuse of antibiotics are among the most important factors in resistance development, and effective antibiotic stewardship measures are needed to optimize outcomes. Selection of appropriate antimicrobials relies on accurate and timely antimicrobial susceptibility testing. However, the availability of clinical breakpoints and in vitro susceptibility testing often lags behind regulatory approval by several years for new antimicrobials. A Working Group of clinical/medical microbiologists from Brazil, Canada, Mexico, Saudi Arabia, Russia and the UK recently examined issues surrounding antimicrobial susceptibility testing for novel antibiotics. While commercially available tests are being developed, potential surrogate antibiotics may be used as marker of susceptibility. Using tedizolid as an example of a new antibiotic, this special report makes recommendations to optimize routine susceptibility reporting

    Perceptual Effects of the Degree of Articulation in HMM-Based Speech Synthesis

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    Strong fragmentation of low-energy electromagnetic excitation strength in 117^{117}Sn

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    Results of nuclear resonance fluorescence experiments on 117^{117}Sn are reported. More than 50 γ\gamma transitions with Eγ<4E_{\gamma} < 4 MeV were detected indicating a strong fragmentation of the electromagnetic excitation strength. For the first time microscopic calculations making use of a complete configuration space for low-lying states are performed in heavy odd-mass spherical nuclei. The theoretical predictions are in good agreement with the data. It is concluded that although the E1 transitions are the strongest ones also M1 and E2 decays contribute substantially to the observed spectra. In contrast to the neighboring even 116−124^{116-124}Sn, in 117^{117}Sn the 1−1^- component of the two-phonon [21+⊗31−][2^+_1 \otimes 3^-_1] quintuplet built on top of the 1/2+^+ ground state is proved to be strongly fragmented.Comment: 4 pages, 3 figure

    A study of the behavioural response of whales to the noise of seismic air guns: design, methods and progress

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    The concern about the effects of the noise of human activities on marine mammals, particularly whales, has led to a substantial amount of research but there is still much that is not understood, particularly in terms of the behavioural responses to noise and the longer term biological consequences of these responses. There are many challenges in conducting experiments that adequately assess behavioural reactions of whales to noise. These include the need to obtain an adequate sample size with the necessary controls and to measure the range of variables likely to affect the observed response. Analysis is also complex. Well designed experiments are complex and logistically difficult, and thus expensive. This paper discusses the challenges involved and how these are being met in a major series of experiments in Australian waters on the response of humpback whales to the noise of seismic airgun arrays. The project is known as BRAHSS (Behavioural Response of Australian Humpback whales to Seismic Surveys) and aims to provide the information that will allow seismic surveys to be conducted efficiently with minimal impact on whales. It also includes a study of the response to ramp-up in sound level which is widely used at the start of operations, but for which there is little information to show that it is effective. BRAHSS also aims to infer the longer term biological significance of the responses from the results and the knowledge of normal behaviour. The results are expected to have relevance to other sources and species
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