A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279

It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and gamma-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10^5 gravitational radii.Comment: Published in Nature issued on 18 February 2010. Corresponding authors: Masaaki Hayashida and Greg Madejsk

Evolutionary Map of the Universe (EMU): 18-cm OH-maser discovery in ASKAP continuum images of the SCORPIO field

Abstract Low- and intermediate-mass stars end their life dispersing their outer layers into the circumstellar medium, during the asymptotic and post-asymptotic giant branch phases. OH masers at 18 cm offer an effective way to probe their circumstellar environment. In this work we present the discovery of seven OH maser sources likely associated with such evolved stars from the visual inspection of ASKAP continuum images. These seven sources do not emit real continuum emission, but the high sensitivity of our images allows us to detect their maser emission, resembling continuum sources. To confirm their nature, we carried out spectral-line observations with ATCA. All the sources showed the double-peaked spectra at 1612 MHz, typical of evolved stars. The detection of maser emission in continuum images can be a complementary and easy-to-use method to discover new maser sources with the large-area deep surveys conducted with the SKA precursors. The implication for radio stars studies are remarkable since pure OH maser sources (i.e. with no continuum associated) represent, at a sensitivity of $100\ \mu \mathrm{Jy\ beam}^{-1}$, about 4 percent of all Galactic sources and by far the most numerous stellar population.</jats:p

A first glimpse at the Galactic plane with the ASKAP: the SCORPIO field

In the broad context of the Australian Square Kilometer Array Pathfinder (ASKAP) early-science phase and preparation for the related surveys, we report the first radio observations towards the Galactic plane. The targeted field was chosen to encompass the entire SCORPIO survey, one of the several pathfinder projects for the Evolutionary Map of the Universe survey planned with the ASKAP. The observations were carried out in 2018 January at a central frequency of 912 MHz, with 15 operational antennas, and covered a total area of about 40 square degrees in three different pointings. The final image has a resolution of 24.1 × 21.1 arcsec2 and a median rms of 541 μJy beam−1⁠. We were able to extract 3545 candidate sources, 75 per cent of them point sources. For a preliminary validation, a comparison with the 843 MHz Molonglo Galactic Plane Survey is presented. Although the present observations were obtained with the ASKAP only partially deployed, its unique capability to map complex sources, such as those inhabiting the Galactic plane, at different angular scales, is highlighted. Within the SCORPIO field all the previously classified H II regions, Planetary Nebulae (PNe), and supernovae remnants (SNRs), previously known to be radio sources, were detected. We also report new radio detections from several H II regions previously classified as ‘candidates’ or ‘radio quiet’ and from half of all the PNe in the SCORPIO field with robust classification. Most notably, we find numerous unclassified, extended sources which constitute a promising sample of candidates H II regions and SNRs

Erythropoietin: a multimodal neuroprotective agent

The tissue protective functions of the hematopoietic growth factor erythropoietin (EPO) are independent of its action on erythropoiesis. EPO and its receptors (EPOR) are expressed in multiple brain cells during brain development and upregulated in the adult brain after injury. Peripherally administered EPO crosses the blood-brain barrier and activates in the brain anti-apoptotic, anti-oxidant and anti-inflammatory signaling in neurons, glial and cerebrovascular endothelial cells and stimulates angiogenesis and neurogenesis. These mechanisms underlie its potent tissue protective effects in experimental models of stroke, cerebral hemorrhage, traumatic brain injury, neuroinflammatory and neurodegenerative disease. The preclinical data in support of the use of EPO in brain disease have already been translated to first clinical pilot studies with encouraging results with the use of EPO as a neuroprotective agent

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Induction of signalling in non-erythroid cells by pharmacological levels of erythropoietin

Erythropoiesis is maintained by the hormone erythropoietin (Epo) binding to its cognate receptor (EpoR) on erythroid progenitor cells. The Epo-EpoR interaction initiates a signal transduction process that regulates the survival, growth and differentiation of these cells. Originally perceived as highly lineage-restricted, Epo is now recognised to have pleiotropic effects extending beyond the maintenance of red cell mass. Functional interactions between Epo and EpoR have been demonstrated in numerous cells and tissues. EpoR expression on neoplastic cells leads to concern that recombinant human erythropoietin, used to treat anaemia in cancer patients, may augment tumour growth. Here we demonstrate that EPO, at pharmacological concentrations, can activate three major signalling cascades, viz. the Jak2/STAT5, Ras/ERK and PI3K/Akt pathways in non-small cell lung carcinoma (NSCLC) cell lines. EpoR synthesis is normally under the control of GATA-1, but NSCLC cells exhibit decreased GATA-1 levels compared to GATA-2, -3 and -6, suggesting that GATA-1 is not essential for EpoR production. The increased Epo-induced signalling was not associated with a growth advantage for the NSCLC cells

All-in-one low-intensity pulsed ultrasound stimulation system using piezoelectric micromachined ultrasonic transducer (pMUT) arrays for targeted cell stimulation

A novel cell-stimulation system was fabricated using 10 x 29 piezoelectric micromachined ultrasonic transducer (pMUT) arrays for targeted ultrasonic cell stimulation. Both the diameter of a single pMUT element and the edge-toedge gap were 120 mu m, and the size of a pMUT array was 2.27 x 6.84mm, to be placed at the bottom of a Transwell. The measured resonance frequency of a single pMUTelement was 1.48 +/- 0.13 MHz and the measured acoustic intensity of the pMUT array was 0.15 +/- 0.03 MPa at 1 mm away from the transducer. A pMUT array was mounted on a print circuit board (PCB), which was designed in accordance with the size of a 12-well Transwell. The Transwell was placed on the PCB and wire bonding was performed to electrically connect the PCB and pMUT arrays. After wiring, the PCB and pMUT arrays were coated with 2.6-mu m thick parylene-C to ensure biocompatibility and waterproofing. PC12 cells were used for ultrasonic cell stimulation tests to examine the proposed all-in-one low-intensity pulsed ultrasound stimulation system. Various stimulation times and duty cycles were used simultaneously for cell proliferation in a confined cell culture environment. All stimulation groups showed increased cell proliferation rates, in the range 138-166%, versus the proliferation rate of the control group.DGIST R&amp;D Program of the Ministry of Science, ICT and Future Planning of Korea [17-BD-0404]; Civil &amp; Military Technology Cooperation Program through the National Research Foundation of Korea (NRF) - Ministry of Science and ICT [2014M3C1A9060874, 2017K1A1A2013237]SCI(E)ARTICLE41