1,108 research outputs found
A promising new ELISA diagnostic test for cattle babesiosis based on Babesia bigemina Apical Membrane Antigen-1.
Babesiosis due to Babesia bigemina is a relevant tick‑borne disease, affecting cattle worldwide. Many surface proteins of the pathogen including the Apical Membrane Antigen 1 (AMA‑1) ‑ have been analysed for vaccine and diagnostic purposes. This study focused on B. bigemina AMA‑1 and on its use for the assessment of diagnostic tests. After bioinformatic analyses, AMA‑1 codifying region was amplified and cloned into an expression vector used to induce protein synthesis in Escherichia coli cells. AMA‑1 was purified by affinity chromatography and used to set up the best condition for an ELISA protocol. Bovine field sera positive to B. bigemina were used to evaluate the presence of anti‑AMA‑1 antibodies. In order to verify the assay specificity, sera positive to Babesia bovis or to the piroplasm Theileria annulata were also included. Significant differences were obtained between sera negative to both B. bigemina and B. bovis and samples positive to B. bigemina, to B. bovis or to both pathogens. No significant reaction was observed with T. annulata positive sera. The results showed that AMA‑1 protein is suitable to be used as antigen in diagnostic assays for babesiosis diagnosis in cattle, as it does not show any cross reaction with anti-T. annulata antibodies
Grid computing technologies for renewable electricity generator monitoring and control
In this paper we discuss the use of real-time Grid computing for the monitoring, control and simulation of renewable electricity generators and their associated electrical networks. We discuss briefly the architectural design of GRIDCC and how we have integrated a number of real (solar, CHP) and simulated conventional power generators into the GRIDCC environment. A local weather station has also been attached to an Instrument Manager to alert experts appropriately when the Solar Array is not generating. The customised remote control and monitoring environment (a virtual control room), distributed using a standard web server, is discussed
Malin 1: interacting galaxy pair?
Malin 1 is a unique, extraordinarily large low surface brightness galaxy. The
structure and the origins of the galaxy are poorly understood. The reason for
such a situation is an absence of detailed observational data, especially, of
high-resolution kinematics. In this Letter we study the stellar kinematics of
the inner part (r < 15 kpc) of Malin 1. We present spectroscopic arguments in
favour of a small galaxy - Malin 1B - being a companion probably interacting
with the main galaxy - Malin 1. This object is clearly seen in many published
images of Malin 1 but is not mentioned in any astronomical databases. Malin 1B
is located at the projected distance of 14 kpc from the Malin 1's nucleus and
has small - 6516 km/s - relative velocity, which we determined for the
first time. We suggest that ongoing interaction with Malin 1B can explain main
morphological features of the Malin 1's central region - two-armed spiral
structure, a bar, and an external one-armed spiral pattern. We also
investigated the large scale environment of Malin 1 and postulate that the
galaxy SDSS J123708.91+142253.2 might be responsible for the formation of
extended low-surface brightness envelope by means of head-on collision with
Malin 1 (in the framework of collision scenario proposed by Mapelli et al.
2008). To test the collisional origins of Malin 1 global structure, more
observational data and new numerical models are needed.Comment: 5 pages, 4 figures, accepted for publication in MNRA
Target-Selective Drug Delivery through Liposomes Labeled with Oligobranched Neurotensin Peptides.
The structure and the in vitro behavior of liposomes filled with the cytotoxic drug doxorubicin (Doxo) and functionalized on the external surface with a branched moiety containing four copies of the 8-13 neurotensin (NT) peptide is reported. The new functionalized liposomes, DOPC-NT(4) Lys(C(18) )(2) , are obtained by co-aggregation of the DOPC phospholipid with a new synthetic amphiphilic molecule, NT(4) Lys(C(18) )(2) , which contains a lysine scaffold derivatized with a lipophilic moiety and a tetrabranched hydrophilic peptide, NT8-13, a neurotensin peptide fragment well known for its ability to mimic the neurotensin peptide in receptor binding ability. Dynamic light scattering measurements indicate a value for the hydrodynamic radius (RH) of 88.3±4.4 nm. The selective internalization and cytotoxicity of DOPC-NT(4) Lys(C(18) )(2) liposomes containing Doxo, as compared to pure DOPC liposomes, were tested in HT29 human colon adenocarcinoma and TE671 human rhabdomyosarcoma cells, both of which express neurotensin receptors. Peptide-functionalized liposomes show a clear advantage in comparison to pure DOPC liposomes with regard to drug internalization in both HT29 and TE671 tumor cells: FACS analysis indicates an increase in fluorescence signal of the NT(4) -liposomes, compared to the DOPC pure analogues, in both cell lines; cytotoxicity of DOPC-NT(4) Lys(C(18) )(2) -Doxo liposomes is increased four-fold with respect to DOPC-Doxo liposomes in both HT29 and TE671 cell lines. These effects could to be ascribed to the higher rate of internalization for DOPC-NT(4) Lys(C(18) )(2) -Doxo liposomes, due to stronger binding driven by a lower dissociation constant of the NT(4) -liposomes that bind the membrane onto a specific protein, in contrast to DOPC liposomes, which approach the plasma membrane unselectively
String Theoretical Interpretation for Finite N Yang-Mills Theory in Two-Dimensions
We discuss the equivalence between a string theory and the two-dimensional
Yang-Mills theory with SU(N) gauge group for finite N. We find a sector which
can be interpreted as a sum of covering maps from closed string world-sheets to
the target space, whose covering number is less than N. This gives an
asymptotic expansion of 1/N whose large N limit becomes the chiral sector
defined by D.Gross and W.Taylor. We also discuss that the residual part of the
partition function provides the non-perturbative corrections to the
perturbative expansion.Comment: 15 pages, no figures, LaTeX2e, typos corrected, final version to
appear in Modern Physics Letters
Molecular gas and star formation in the Tidal Dwarf Galaxy VCC 2062
The final, definitive version of this paper has been published in A&A, Vol 590, A92, June 2016, doi: 10.1051/0004-6361/201527887. Reproduced with permission from Astronomy & Astrophysics, © ESO.The physical mechanisms driving star formation (SF) in galaxies are still not fully understood. Tidal dwarf galaxies (TDGs), made of gas ejected during galaxy interactions, seem to be devoid of dark matter and have a near-solar metallicity. The latter makes it possible to study molecular gas and its link to SF using standard tracers (CO, dust) in a peculiar environment. We present a detailed study of a nearby TDG in the Virgo Cluster, VCC 2062, using new high-resolution CO(1--0) data from the Plateau de Bure, deep optical imaging from the Next Generation Virgo Cluster Survey (NGVS), and complementary multiwavelength data. Until now, there was some doubt whether VCC 2062 was a true TDG, but the new deep optical images from the NGVS reveal a stellar bridge between VCC 2062 and its parent galaxy, NGC 4694, which is clear proof of its tidal origin. Several high-resolution tracers (\halpha, UV, 8~\mi, and 24~\mi) of the star formation rate (SFR) are compared to the molecular gas distribution as traced by the CO(1-0). Coupled with the SFR tracers, the NGVS data are used with the CIGALE code to model the stellar populations throughout VCC 2062, yielding a declining SFR in the recent past, consistent with the low \halpha/UV ratio, and a high burst strength. HI emission covers VCC 2062, whereas the CO is concentrated near the HI maxima. The CO peaks correspond to two very distinct regions: one with moderate SF to the NE and one with only slightly weaker CO emission but with nearly no SF. Even where SF is clearly present, the SFR is below the value expected from the surface density of the molecular and the total gas as compared to spiral galaxies and other TDGs. After discussing different possible explanations, we conclude that the low surface brightness is a crucial parameter to understand the low SFR.Peer reviewe
PEXO : a global modeling framework for nanosecond timing, microsecond astrometry, and μm/s radial velocities
54 pages, 2 tables, 19 figures, accepted for publication in ApJS, PEXO is available at https://github.com/phillippro/pexoThe ability to make independent detections of the signatures of exoplanets with complementary telescopes and instruments brings a new potential for robust identification of exoplanets and precision characterization. We introduce PEXO, a package for Precise EXOplanetology to facilitate the efficient modeling of timing, astrometry, and radial velocity data, which will benefit not only exoplanet science but also various astrophysical studies in general. PEXO is general enough to account for binary motion and stellar reflex motions induced by planetary companions and is precise enough to treat various relativistic effects both in the solar system and in the target system. We also model the post-Newtonian barycentric motion for future tests of general relativity in extrasolar systems. We benchmark PEXO with the pulsar timing package TEMPO2 and find that PEXO produces numerically similar results with timing precision of about 1 ns, space-based astrometry to a precision of 1{\mu}as, and radial velocity of 1 {\mu}m/s and improves on TEMPO2 for decade-long timing data of nearby targets, due to its consideration of third-order terms of Roemer delay. PEXO is able to avoid the bias introduced by decoupling the target system and the solar system and to account for the atmospheric effects which set a practical limit for ground-based radial velocities close to 1 cm/s. Considering the various caveats in barycentric correction and ancillary data required to realize cm/s modeling, we recommend the preservation of original observational data. The PEXO modeling package is available at GitHub (https://github.com/phillippro/pexo).Peer reviewe
West Nile virus transmission. results from the integrated surveillance system in Italy, 2008 to 2015
IIn Italy a national Plan for the surveillance of imported and autochthonous human vector-borne diseases (chikungunya, dengue, Zika virus disease and West Nile virus (WNV) disease) that integrates human and veterinary (animals and vectors) surveillance, is issued and revised annually according with the observed epidemiological changes. Here we describe results of the WNV integrated veterinary and human surveillance systems in Italy from 2008 to 2015. A real time data exchange protocol is in place between the surveillance systems to rapidly identify occurrence of human and animal cases and to define and update the map of affected areas i.e. provinces during the vector activity period from June to October. WNV continues to cause severe illnesses in Italy during every transmission season, albeit cases are sporadic and the epidemiology varies by virus lineage and geographic area. The integration of surveillance activities and a multidisciplinary approach made it possible and have been fundamental in supporting implementation of and/or strengthening preventive measures aimed at reducing the risk of transmission of WNV trough blood, tissues and organ donation and to implementing further measures for vector control
Gas Accretion and Star Formation Rates
Cosmological numerical simulations of galaxy evolution show that accretion of
metal-poor gas from the cosmic web drives the star formation in galaxy disks.
Unfortunately, the observational support for this theoretical prediction is
still indirect, and modeling and analysis are required to identify hints as
actual signs of star-formation feeding from metal-poor gas accretion. Thus, a
meticulous interpretation of the observations is crucial, and this
observational review begins with a simple theoretical description of the
physical process and the key ingredients it involves, including the properties
of the accreted gas and of the star-formation that it induces. A number of
observations pointing out the connection between metal-poor gas accretion and
star-formation are analyzed, specifically, the short gas consumption time-scale
compared to the age of the stellar populations, the fundamental metallicity
relationship, the relationship between disk morphology and gas metallicity, the
existence of metallicity drops in starbursts of star-forming galaxies, the
so-called G dwarf problem, the existence of a minimum metallicity for the
star-forming gas in the local universe, the origin of the alpha-enhanced gas
forming stars in the local universe, the metallicity of the quiescent BCDs, and
the direct measurements of gas accretion onto galaxies. A final section
discusses intrinsic difficulties to obtain direct observational evidence, and
points out alternative observational pathways to further consolidate the
current ideas.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
Springe
Host defence peptide plectasin targets bacterial cell wall precursor lipid II by a calcium-sensitive supramolecular mechanism
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