Mechanical properties of flax and hemp yarns designed for the manufacturing of geotextiles. Improvement of the resistance to soil born microorganisms.

Geotextiles are widely used to stabilize river banks from erosion when these ones are restored into vegetal covered areas as mentioned by European regulations. For these applications imported coir (coconut shell fibres) based geotextiles are generally used because coir fibres show a good resistance to soil degradation. In Europe, flax and hemp plants are already grown for textile, building or oil applications. By-products of these industries such as flax tows and short hemp fibres were used to manufacture yarns. The resistance to degradation via the measurement of the mechanical properties of these yarns submitted to enzymatic (cellulase) and microbial attacks (Cellvibrio gandavensis) mimicking soil degradation was evaluated. Large decreases in mechanical properties were observed, even though these ones were still higher than the as received reference coir material. After impregnation by chitosan of the fibres, the tensile properties of the yarns globally remained unchanged after severe attacks. The chitosan acts as a protection against the soil microorganism attacks. As a consequence, flax and hemp by-products could be good candidates for local manufacturing of biodegradable geotextiles

Visible Light-Driven Water Oxidation Catalyzed by Ruthenium Complexes

A shift in energy dependence from fossil fuels to sustainable and carbon-neutral alternatives is a daunting challenge that faces the human society. Light harvesting for the production of solar fuels has been extensively investigated as an attractive approach to clean and abundant energy. An essential component in solar energy conversion schemes is a catalyst for water oxidation. Ruthenium-based catalysts have received significant attention due to their ability to efficiently mediate the oxidation of water. In this context, the design of robust catalysts capable of driving water oxidation at low overpotential is a key challenge for realizing efficient visible light-driven water splitting. Herein, recent progress in the development within this field is presented with a focus on homogeneous ruthenium-based systems and surface-immobilized ruthenium assemblies for photo-induced oxidation of water

Structural analysis of herpes simplex virus by optical super-resolution imaging.

Herpes simplex virus type-1 (HSV-1) is one of the most widespread pathogens among humans. Although the structure of HSV-1 has been extensively investigated, the precise organization of tegument and envelope proteins remains elusive. Here we use super-resolution imaging by direct stochastic optical reconstruction microscopy (dSTORM) in combination with a model-based analysis of single-molecule localization data, to determine the position of protein layers within virus particles. We resolve different protein layers within individual HSV-1 particles using multi-colour dSTORM imaging and discriminate envelope-anchored glycoproteins from tegument proteins, both in purified virions and in virions present in infected cells. Precise characterization of HSV-1 structure was achieved by particle averaging of purified viruses and model-based analysis of the radial distribution of the tegument proteins VP16, VP1/2 and pUL37, and envelope protein gD. From this data, we propose a model of the protein organization inside the tegument.This work was supported by grants from the Leverhulme Trust (grant RPG-2012-793), the Royal Society (University Research Fellowship to C.M.C.), the Engineering and Physical Sciences Research Council, UK (grant EP/H018301/1) and by the Medical Research Council (grant MR/K015850/1).This is the final published version. It first appeared at http://www.nature.com/ncomms/2015/150122/ncomms6980/full/ncomms6980.html

Galaxy Zoo: Are Bars Responsible for the Feeding of Active Galactic Nuclei at 0.2 < z < 1.0?

We present a new study investigating whether active galactic nuclei (AGN) beyond the local universe are preferentially fed via large-scale bars. Our investigation combines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS, COSMOS, and GOODS-S surveys to create samples of face-on, disc galaxies at 0.2 < z < 1.0. We use a novel method to robustly compare a sample of 120 AGN host galaxies, defined to have 10^42 erg/s < L_X < 10^44 erg/s, with inactive control galaxies matched in stellar mass, rest-frame colour, size, Sersic index, and redshift. Using the GZH bar classifications of each sample, we demonstrate that AGN hosts show no statistically significant enhancement in bar fraction or average bar likelihood compared to closely-matched inactive galaxies. In detail, we find that the AGN bar fraction cannot be enhanced above the control bar fraction by more than a factor of two, at 99.7% confidence. We similarly find no significant difference in the AGN fraction among barred and non-barred galaxies. Thus we find no compelling evidence that large-scale bars directly fuel AGN at 0.2<z<1.0. This result, coupled with previous results at z=0, implies that moderate-luminosity AGN have not been preferentially fed by large-scale bars since z=1. Furthermore, given the low bar fractions at z>1, our findings suggest that large-scale bars have likely never directly been a dominant fueling mechanism for supermassive black hole growth.Comment: 13 pages, 5 figures, 2 tables, accepted by MNRA

Risks and Benefits Associated With Prestroke Antiplatelet Therapy Among Patients With Acute Ischemic Stroke Treated With Intravenous Tissue Plasminogen Activator

IMPORTANCE: Intravenous tissue plasminogen activator (tPA) is known to improve outcomes in ischemic stroke; however, many patients may have been receiving antiplatelet therapy before acute ischemic stroke and could face an increased risk for bleeding when treated with tPA. OBJECTIVE: To assess the risks and benefits associated with prestroke antiplatelet therapy among patients with ischemic stroke who receive intravenous tPA. DESIGN, SETTING, AND PARTICIPANTS: This observational study used data from the American Heart Association and American Stroke Association Get With the Guidelines-Stroke registry, which included 85 072 adult patients with ischemic stroke who received intravenous tPA in 1545 registry hospitals from January 1, 2009, through March 31, 2015. Data were analyzed during the same period. EXPOSURES: Prestroke antiplatelet therapy before tPA administration for acute ischemic stroke. MAIN OUTCOMES AND MEASURES: Symptomatic intracranial hemorrhage (sICH), in-hospital mortality, discharge ambulatory status, and modified Rankin Scale score (range, 0 [no symptoms] to 6 [death]). RESULTS: Of the 85 072 registry patients, 38 844 (45.7%) were receiving antiplatelet therapy before admission; 46 228 patients (54.3%) were not. Patients receiving antiplatelet therapy were older (median [25th-75th percentile] age, 76 [65-84] vs 68 [56-80] years) and had a higher prevalence of cardiovascular risk factors. The unadjusted rate of sICH was higher in patients receiving antiplatelet therapy (5.0% vs 3.7%). After risk adjustment, prior use of antiplatelet agents remained associated with higher odds of sICH compared with no use (adjusted odds ratio [AOR], 1.18 [95% CI, 1.10-1.28]; absolute difference, +0.68% [95% CI, 0.36%-1.01%]; number needed to harm [NNH], 147). Among patients enrolled on October 1, 2012, or later, the highest odds (95% CIs) of sICH were found in 15 116 patients receiving aspirin alone (AOR, 1.19 [1.06- 1.34]; absolute difference [95% CI], +0.68% [0.21%-1.20%]; NNH, 147) and 2397 patients receiving dual antiplatelet treatment of aspirin and clopidogrel (AOR, 1.47 [1.16-1.86]; absolute difference, +1.67% [0.58%-3.00%]; NNH, 60). The risk for in-hospital mortality was similar between those who were and were not receiving antiplatelet therapy after adjustment (8.0% vs 6.6%; AOR, 1.00 [0.94-1.06]; nonsignificant absolute difference, -0.01% [-0.37% to 0.36%]). However, patients receiving antiplatelet therapy had a greater risk-adjusted likelihood of independent ambulation (42.1% vs 46.6%; AOR, 1.13 [1.08-1.17]; absolute difference, +2.23% [1.55%-2.92%]; number needed to treat, 43) and better functional outcomes (modified Rankin Scale score, 0-1) at discharge (24.1% vs 27.8%; AOR, 1.14; 1.07-1.22; absolute difference, +1.99% [0.78%-3.22%]; number needed to treat, 50). CONCLUSIONS AND RELEVANCE: Among patients with an acute ischemic stroke treated with intravenous tPA, those receiving antiplatelet therapy before the stroke had a higher risk for sICH but better functional outcomes than those who were not receiving antiplatelet therapy

Bar Evolution Over the Last Eight Billion Years: A Constant Fraction of Strong Bars in GEMS

One third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question of how bars evolve over cosmological times has yet to be addressed, and even the frequency of bars at intermediate redshifts remains controversial. We investigate the frequency of bars out to z~1.0 drawing on a sample of 1590 galaxies from the GEMS survey, which provides morphologies from HST ACS two-color images, and highly accurate redshifts from the COMBO-17 survey. We identify spiral galaxies using the Sersic index, concentration parameter, and rest-frame color. We characterize bars and disks by fitting ellipses to F606W and F850LP images, taking advantage of the two bands to minimize bandpass shifting. We exclude highly inclined (i>60 deg) galaxies to ensure reliable morphological classifications, and apply completeness cuts of M_v <= -19.3 and -20.6. More than 40% of the bars that we detect have semi major axes a<0.5" and would be easily missed in earlier surveys without the small PSF of ACS. The bars that we can reliably detect are fairly strong (with ellipticities e>=0.4) and have a in the range ~1.2-13 kpc. We find that the optical fraction of such strong bars remains at ~(30% +- 6%) from the present-day out to look-back times of 2-6 Gyr (z~0.2-0.7) and 6-8 Gyr (z~0.7-1.0); it certainly shows no sign of a drastic decline at z>0.7. Our findings of a large and similar bar fraction at these three epochs favor scenarios in which cold gravitationally unstable disks are already in place by z~1, and where on average bars have a long lifetime (well above 2 Gyr). The distributions of structural bar properties in the two slices are, however, not statistically identical and therefore allow for the possibility that the bar strengths and sizes may evolve over time.Comment: Accepted by ApJ Letters, to appear in Nov 2004 issue. Minor revisions,updated reference

Barred Galaxies in the Abell 901/2 Supercluster with STAGES

We present a study of bar and host disk evolution in a dense cluster environment, based on a sample of ~800 bright (MV <= -18) galaxies in the Abell 901/2 supercluster at z~0.165. We use HST ACS F606W imaging from the STAGES survey, and data from Spitzer, XMM-Newton, and COMBO-17. We identify and characterize bars through ellipse-fitting, and other morphological features through visual classification. (1) We explore three commonly used methods for selecting disk galaxies. We find 625, 485, and 353 disk galaxies, respectively, via visual classification, a single component S'ersic cut (n <= 2.5), and a blue-cloud cut. In cluster environments, the latter two methods miss 31% and 51%, respectively, of visually-identified disks. (2) For moderately inclined disks, the three methods of disk selection yield a similar global optical bar fraction (f_bar-opt) of 34% +10%/-3%, 31% +10%/-3%, and 30% +10%/-3%, respectively. (3) f_bar-opt rises in brighter galaxies and those which appear to have no significant bulge component. Within a given absolute magnitude bin, f_bar-opt is higher in visually-selected disk galaxies that have no bulge as opposed to those with bulges. For a given morphological class, f_bar-opt rises at higher luminosities. (4) For bright early-types, as well as faint late-type systems with no evident bulge, the optical bar fraction in the Abell 901/2 clusters is comparable within a factor of 1.1 to 1.4 to that of field galaxies at lower redshifts (5) Between the core and the virial radius of the cluster at intermediate environmental densities, the optical bar fraction does not appear to depend strongly on the local environment density and varies at most by a factor of ~1.3. We discuss the implications of our results for the evolution of bars and disks in dense environments.Comment: accepted for publication in ApJ, abstract abridged, for high resolution figures see http://www.as.utexas.edu/~marinova/STAGES/STAGES_bars.pd

Chandra and Very Large Array Observations of the Nearby Sd Galaxy NGC 45

We present an analysis of high angular resolution observations made in the X-ray and the radio with the Chandra X-ray Observatory and the Karl Jansky Very Large Array (VLA), respectively, of the nearby spiral galaxy NGC 45. This galaxy is the third that we have considered in a study of the supernova remnant (SNR) populations of nearby spiral galaxies and the present work represents the first detailed analysis of the discrete X-ray and radio source populations of this galaxy. We analyzed data sets from the three pointed observations made of this galaxy with Chandra along with a merged data set obtained from combining these data sets: the total effective exposure time of the merged data set is 63515 s. A total of 25 discrete X-ray sources are found in the entire field of view of the ACIS-S3 chip, with 16 sources found within the visual extent of the galaxy. We estimate that as many as half of the sources detected in the entire field of view of the ACIS-S3 chip and seven of the sources detected in the optical extent of NGC 45 may be background sources. We analyzed the spectral properties of the discrete X-ray sources within the galaxy and conclude that the majority of these sources are X-ray binaries. We have searched for counterparts at different wavelengths to the discrete X-ray sources and we find two associations: one with a star cluster and the other with a background galaxy. We have found one source that is clearly variable within one observation and seven that are seen to vary from one observation to another. We also conduct a photometric analysis to determine the near-infrared fluxes of the discrete X-ray sources in Spitzer Infrared Array Camera channels. We constructed a cumulative luminosity function of the discrete X-ray sources seen toward NGC 45: taking into account simultaneously the luminosity function of background sources, the fitted slope of the cumulative luminosity function Γ = –1.3_(-1.6)^(+0.7) (all error bounds correspond to 90% confidence intervals). The VLA observations reveal seven discrete radio sources: we find no overlaps between these sources and the X-ray detected sources. Based on their measured spectral indices and their locations with respect to the visible extent of NGC 45, we classify one source as a candidate radio SNR associated with the galaxy and the others as likely background galaxies seen in projection toward NGC 45. Finally, we discuss the properties of a background cluster of galaxies (denoted as CXOU J001354.2–231254.7) seen in projection toward NGC 45 and detected by the Chandra observations. The fit parameters to the extracted Chandra spectra of this cluster are a column density N_H = 0.07(<0.14) × 10^(22) cm^(−2), a temperature kT = 4.22_(-1.42)^(+2.08) keV, an abundance Z = 0.30(<0.75) relative to solar and a redshift z = 0.28 ± 0.14. From the fit parameters we derive an electron number density n_e = 4(±1) × 10^(−3) cm^(−3), an unabsorbed X-ray luminosity L_(0.5-7.0keV) ~ 8.77(±0.96) × 10^(43) erg s^(−1) for the cluster and an X-ray emitting mass M = 2.32(±1.75) × 10^(12)M_☉