133 research outputs found
A newly identified galaxy group thanks to tidal streams of intragroup light
In the accretion-driven growth scenario, part of the intracluster light is
formed in the group environment. We report the serendipitous discovery of a
group of galaxies with signs of diffuse light in the foreground of the known
galaxy cluster MACS J0329-0211 at z=0.45. Our investigation began with the
detection of diffuse light streams around a pair of bright galaxies in the
southeastern region of a Suprime-Cam image of the galaxy cluster MACS
J0329-0211. Our analysis is based on the extended CLASH-VLT redshift catalog
and on new spectroscopic data obtained ad hoc with the Italian Telescopio
Nazionale Galileo. We use the density reconstruction method to analyze the
redshift distribution of the galaxies in the region around the galaxy pair. We
also use available photometric and X-ray data to better characterize the
properties of the group. Thanks to the large amount of redshift data collected
in this region, we have been able to discover the existence of a group of
galaxies, here called GrG J0330-0218, which is associated with the pair of
galaxies. These are the two brightest group galaxies (BGG1 and BGG2). We
extracted 41 group members from the redshift catalog and estimate a mean
redshift z=0.1537 and a line-of-sight velocity dispersion sigmav=370 km/s. In
the phase-space diagram, the distribution of the galaxies of GrG J0330-0218
follows the characteristic trumpet-shaped pattern, which is related to the
escape velocity of galaxy clusters, suggesting that the group is a virialized
structure. Under this assumption, the mass of the group is M200 about 6E13
Msun. We also measured a mass-to-light ratio of 130 Msun/Lsun and a luminosity
fraction of diffuse light of about 20% within 0.5 R200. We conjecture that
galaxy pairs that are surrounded by diffuse light, probably due to tidal
interactions, can serve as signposts for groups.Comment: Astronomy & Astrophysics accepted, 13 pages, 10 figure
A novel synthetic peptide from a tomato defensin exhibits antibacterial activities against Helicobacter pylori
Defensins are a class of cysteine-rich proteins, which exert broad spectrum antimicrobial activity. In this work, we used a bioinformatic approach to identify putative defensins in the tomato genome. Fifteen proteins had a mature peptide that includes the well-conserved tetradisulfide array. We selected a representative member of the tomato defensin family; we chemically synthesized its gamma-motif and tested its antimicrobial activity. Here, we demonstrate that the synthetic peptide exhibits potent antibacterial activity against Gram-positive bacteria, such as Staphylococcus aureus A170, Staphylococcus epidermidis, and Listeria monocytogenes, and Gram-negative bacteria, including Salmonella enterica serovar Paratyphi, Escherichia coli, and Helicobacter pylori. In addition, the synthetic peptide shows minimal (<5%) hemolytic activity and absence of cytotoxic effects against THP-1 cells. Finally, SolyC exerts an anti-inflammatory activity in vitro, as it downregulates the level of the proinflammatory cytokines TNF-alpha and IFN-gamma
Mechanical harvesting of oil olives by trunk shaker with a reversed umbrella interceptor
Trunk shakers are primarily used for the mechanical harvesting of oil olives in intensive orchards. The objective of this trial was to determine the efficiency of mechanical harvesting of olives with a self-propelled trunk shaker with a reversed umbrella interceptor (model F3, SICMA, Catanzaro, Italy), from adult trees of two autochthonous cultivars, ‘Ortice’ and ‘Ortolana’, growing in southern Italy with 6 × 6 m spacing and trained to the vase system. The main characteristics of the trunk shaker were: an engine power of 77 Kw (105 CV), a very-high-frequency vibrating head (1800-2000 vibrations/min), a self-braking system and a 6-meter diameter umbrella opening. The worksite consisted of two workers, one for maneuvering the harvesting machine, and the other for handling the olives. Mechanical harvesting was carried on 30 November 2006 when the fruits of ‘Ortice’ and ‘Ortolana’ had a weight and detachment force around 2.8 g and 3.1 N and 3.8 g and 4.6 N, respectively, and the fruit drop was around 14% and 10%, respectively. Both cultivars had a good production (26.06 and 21.18 kg/tree). The mechanical harvesting yield (percentage of mechanically harvested olives) was very high, reaching values around 97% in both cultivars. Moreover, the low number of workers, the reduced time for the operation (2.5 min/tree), the good yield/tree and the high quantity of harvested fruit allowed a very high work productivity to be obtained: around 302 kg/h/worker for ‘Ortice’ and 246 kg/h/worker for ‘Ortolana’. The quality of the oils extracted from the harvested olives met the requirements set by European law for extra virgin olive oils. The results indicate that the use of a trunk shaker with a reversed umbrella can be an efficient solution for mechanical harvesting of the ‘Ortice’ and ‘Ortolana’ cultivars in southern Italy
Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates
We present a soft x-ray angle-resolved photoemission spectroscopy study of
the overdoped high-temperature superconductors LaSrCuO and
LaEuSrCuO. In-plane and out-of-plane components of
the Fermi surface are mapped by varying the photoemission angle and the
incident photon energy. No dispersion is observed along the nodal
direction, whereas a significant antinodal dispersion is identified.
Based on a tight-binding parametrization, we discuss the implications for the
density of states near the van-Hove singularity. Our results suggest that the
large electronic specific heat found in overdoped LaSrCuO can
not be assigned to the van-Hove singularity alone. We therefore propose quantum
criticality induced by a collapsing pseudogap phase as a plausible explanation
for observed enhancement of electronic specific heat
Neutron powder diffraction study of NaMnO and LiMnO: New insights on spin-charge-orbital ordering
The high-pressure synthesized quasi-one-dimensional compounds NaMnO
and LiMnO are both antiferromagnetic insulators, and here
their atomic and magnetic structures were investigated using neutron powder
diffraction. The present crystal structural analyses of NaMn2O4 reveal that
Mn3+/Mn4+ charge-ordering state exist even at low temperature (down to 1.5 K).
It is evident from one of the Mn sites shows a strongly distorted Mn3+
octahedra due to the Jahn-Teller effect. Above TN = 39 K, a two-dimensional
short-range correlation is observed, as indicated by an asymmetric diffuse
scattering. Below TN, two antiferromagnetic transitions are observed (i) a
commensurate long-range Mn3+ spin ordering below 39 K, and (ii) an
incommensurate Mn4+ spin ordering below 10 K. The commensurate magnetic
structure (kC = 0.5, -0.5, 0.5) follows the magnetic anisotropy of the local
easy axes of Mn3+, while the incommensurate one shows a spin-density-wave order
with kIC = (0,0,0.216). For LiMnO, on the other hand, absence
of a long-range spin ordered state down to 1.5 K is confirmed.Comment: 11 pages, 8 figure
Diagnostic amyloid proteomics: experience of the UK National Amyloidosis Centre
Systemic amyloidosis is a serious disease which is caused when normal circulating proteins misfold and aggregate extracellularly as insoluble fibrillary deposits throughout the body. This commonly results in cardiac, renal and neurological damage. The tissue target, progression and outcome of the disease depends on the type of protein forming the fibril deposit, and its correct identification is central to determining therapy. Proteomics is now used routinely in our centre to type amyloid; over the past 7 years we have examined over 2000 clinical samples. Proteomics results are linked directly to our patient database using a simple algorithm to automatically highlight the most likely amyloidogenic protein. Whilst the approach has proved very successful, we have encountered a number of challenges, including poor sample recovery, limited enzymatic digestion, the presence of multiple amyloidogenic proteins and the identification of pathogenic variants. Our proteomics procedures and approaches to resolving difficult issues are outlined
Evaluation of the Accuracy of Photogrammetric Reconstruction of Bathymetry Using Differential GNSS Synchronized with an Underwater Camera
Photogrammetry is a valuable tool for 3D documentation, mapping, and monitoring of underwater environments. However, the ground control surveys necessary for georeferencing and validation of the reconstructed bathymetry are difficult and time consuming to perform underwater, and thus impractical to scale to larger areas. Underwater direct georeferencing, using a differential GNSS receiver synchronized with an underwater camera system, offers an attractive alternative to surveying underwater ground control points in conditions when the seafloor is clearly visible from the surface. In this paper, the design of an underwater direct georeferencing system using mostly commercial off the shelf components is presented. The accuracy of the system is evaluated against geodetic survey based on trilateration and leveling, as well as by RTK (real time kinematic) positioning using a tilt-compensated GNSS receiver mounted on an extended pole to allow measurements of points in up to 7 m in water depth. Tests were conducted in a controlled outdoor pool setting with depths from 1–3 m, as well as in a 10 m × 10 m test plot established on the seafloor in a near-shore environment by Catalina Island, California at depths from 4–10 m. Comparing the geometry of the photogrammetric reconstruction with the geodetic survey yielded sub centimeter consistency, and 1 mm accuracy in length measurement was achieved when compared with calibrated 0.5 m scale bars. Through repeated surveys of the same area, repeatability of georeferencing is demonstrated within expectations for differential GNSS positioning, with horizontal errors at sub centimeter level, and vertical errors of up to 3 cm in the worst cases. These tests demonstrate the benefits of the underwater direct georeferencing approach in shallow waters, which can be scaled up much more easily than measuring underwater ground control points with traditional approaches, making this an ideal option for collecting accurate bathymetry of the seafloor over large coastal areas with clear waters
Clinical ApoA-IV amyloid is associated with fibrillogenic signal sequence
Apolipoprotein A-IV amyloidosis is an uncommon form of the disease normally resulting in renal and cardiac dysfunction. ApoA-IV amyloidosis was identified in 16 patients attending the National Amyloidosis Centre and in eight clinical samples received for histology review. Unexpectedly, proteomics identified the presence of ApoA-IV signal sequence residues (p.18-43 to p.20-43) in 16/24 trypsin-digested amyloid deposits but in only 1/266 non-ApoA-IV amyloid samples examined. These additional signal residues were also detected in the cardiac sample from the Swedish patient in which ApoA-IV amyloid was first described, and in plasma from a single cardiac ApoA-IV amyloidosis patient. The most common signal-containing peptide observed in ApoA-IV amyloid, p.20-43, and to a far lesser extent the N-terminal peptide, p.21-43, were fibrillogenic in vitro at physiological pH, generating Congo red-positive fibrils. The addition of a single signal-derived alanine residue to the N-terminus has resulted in markedly increased fibrillogenesis. If this effect translates to the mature circulating protein in vivo, then the presence of signal may result in preferential deposition as amyloid, perhaps acting as seed for the main circulating native form of the protein; it may also influence other ApoA-IV-associated pathologies. \ua9 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland
Magnetism and Ion Diffusion in Honeycomb Layered Oxide KNiTeO: First Time Study by Muon Spin Rotation & Neutron Scattering
In the quest of finding novel and efficient batteries, a great interest has
raised in K-based honeycomb layer oxide materials both for their fundamental
properties and potential applications. A key issue in the realization of
efficient batteries based on such compounds, is to understand the K-ion
diffusion mechanism. However, investigation of potassium-ion (K) dynamics
in materials using magneto-spin properties has so far been challenging, due to
its inherently weak nuclear magnetic moment, in contrast to other alkali ions
such as lithium and sodium. Spin-polarised muons, having a high gyromagnetic
ratio, make the muon spin rotation and relaxation (+SR) technique ideal
for probing ions dynamics in weak magneto-spin moment materials. Here we report
the magnetic properties and K+ dynamics in honeycomb layered oxide material of
the KNiTeO using +SR measurements. Our low-temperature
+SR results together with, with complementary magnetic susceptibility,
find an antiferromagnetic transition at 26 K. Further +SR studies
performed at higher temperatures reveal that potassium ions (K) become
mobile above 250 K and the activation energy for the diffusion process is Ea =
121(13) meV. This is the first time that K+ dynamics in potassium-based battery
materials has been measured using +SR. Finally our results also indicate
an interesting possibility that K-ion self diffusion occurs predominantly at
the surface of the powder particles. This opens future possibilities for
improving ion diffusion and device performance using nano-structuring.Comment: 12 pages, 12 figure
Immunocluster provides a computational framework for the nonspecialist to profile high-dimensional cytometry data
High-dimensional cytometry is an innovative tool for immune monitoring in health and disease, and it has provided novel insight into the underlying biology as well as biomarkers for a variety of diseases. However, the analysis of large multiparametric datasets usually requires specialist computational knowledge. Here, we describe ImmunoCluster (https://github.com/ kordastilab/ImmunoCluster), an R package for immune profiling cellular heterogeneity in highdimensional liquid and imaging mass cytometry, and flow cytometry data, designed to facilitate computational analysis by a nonspecialist. The analysis framework implemented within ImmunoCluster is readily scalable to millions of cells and provides a variety of visualization and analytical approaches, as well as a rich array of plotting tools that can be tailored to users’ needs. The protocol consists of three core computational stages: (1) data import and quality control; (2) dimensionality reduction and unsupervised clustering; and (3) annotation and differential testing, all contained within an R-based open-source framework
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