2,235 research outputs found
A search for Galactic transients disguised as gamma-ray bursts
A significant fraction of cosmological gamma-ray bursts (GRBs) are
characterised by a fast rise and exponential decay (FRED) temporal structure.
This is not a distinctive feature of this class, since it is observed in many
Galactic transients and is likely descriptive of a sudden release of energy
followed by a diffusion process. Possible evidence has recently been reported
by Tello et al. (2012) for a Galactic contamination in the sample of FRED GRBs
discovered with Swift. We searched for possible Galactic intruders disguised as
FRED GRBs in the Swift catalogue up to September 2014. We selected 181 FRED
GRBs (2/3 with unknown redshift) and considered different subsamples. We tested
the degree of isotropy through the dipole and the quadrupole moment
distributions, both with reference to the Galaxy and in a
coordinate-system-independent way, as well as with the two-point angular
autocovariance function. In addition, we searched for possible indicators of a
Galactic origin among the spectral and temporal properties of individual GRBs.
We found marginal (~3 sigma) evidence for an excess of FREDs with unknown
redshift towards the Galactic plane compared with what is expected for an
isotropic distribution corrected for the non-uniform sky exposure. However,
when we account for the observational bias against optical follow-up
observations of low-Galactic latitude GRBs, the evidence for anisotropy
decreases to ~2 sigma. In addition, we found no statistical evidence for
different spectral or temporal properties from the bulk of cosmological GRBs.
We found marginal evidence for the presence of a disguised Galactic population
among Swift GRBs with unknown redshift. The estimated fraction is f=(19 +-
11)%, with an upper limit of 34% (90% confidence).Comment: 6 pages, 4 figures, accepted by A&
Traumatic shock and electroshock: the difficult relationship between anatomic pathology and psychiatry in the early 20th century
In the conviction that a look at the past can contribute to a better understanding of the present in the field of science too, we discuss here two aspects of the relationship between early 20th century anatomic pathology and psychiatry that have received very little attention, in Italy at least. There was much debate between these two disciplines throughout the 19th century, which began to lose momentum in the early years of the 20th, with the arrival on the scene of schizophrenia (a disease histologically sine materia) in all its epidemiological relevance. The First World War also contributed to the separation between psychiatry and pathology, which unfolded in the fruitless attempts to identify a histopathological justification for the psychological trauma known as shell shock. This condition was defined at the time as a "strange disorder" with very spectacular symptoms (memory loss, trembling, hallucinations, blindness with no apparent organic cause, dysesthesias, myoclonus, bizarre postures, hemiplegia, and more), that may have found neuropathological grounds only some hundred years later. Among the doctors with a passed involvement in the conflict, Ugo Cerletti, the inventor of electroshock treatment, focused on the problem of schizophrenia without abandoning his efforts to identify its organic factors: if inducing a controlled electric shock, just like an experimentally-induced epileptic seizure, seems to allay the psychotic symptoms and heal the patient, then what happens inside the brain? In seeking histological proof of the clinical effects of electroconvulsive therapy ("the destruction of the pathological synapses"), and attempting to isolate molecules (that he called acroagonins) he believed to be synthesized by neurons exposed to strong electric stimulation, Cerletti extended a hand towards anatomic pathology, and took the first steps towards a neurochemical perspective. However his dedication to finding a microscopic explanation for schizophrenia - in the name of a "somatist" approach that, some years earlier, the psychiatrist Enrico Morselli had labelled "histomania" - was unable to prevent psychiatry from moving further and further away from anatomic pathology
Immunoadherence and complement in cancer-bearing mice.
Shortly after grafting of Ehrlich ascites carcinoma cells, the serum of tumour-bearing mice loses the capacity to mediate immunoadherence phenomena, because of a sharp decrease in the concentration of C3b and C3d, while the cellular receptors for such factors are unaffected by tumour growth. It is suggested that complement is consumed through the alternative pathway which is activated during the inflammatory responses accompanying tumour growth
Synthesis, Conformation and Antiproliferative Activity of Isothiazoloisoxazole 1,1-dioxides
Sixteen new isothiazoloisoxazole 1,1-dioxides, one new isothiazolotriazole and one new isothiazolopyrazole have been synthesised by using 1,3-dipolar cycloadditions to isothiazole 1,1-dioxides. One sub-set of these isothiazoloisoxazoles showed low μM activity against a human breast carcinoma cell line, whilst a second sub-set plus the isothiazolotriazole demonstrated an interesting restricted rotation of sterically hindered bridgehead substituents. A thiazete 1,1-dioxide produced from one of the isothiazole 1,1-dioxides underwent conversion into an unknown 1,2,3-oxathiazolin-2-oxide upon treatment with Lewis acids, but was inert towards 1,3-dipoles and cyclopropenones. Six supporting crystal structures are included
An Overview on ERAP Roles in Infectious Diseases
Endoplasmic reticulum (ER) aminopeptidases ERAP1 and ERAP2 (ERAPs) are crucial enzymes shaping the major histocompatibility complex I (MHC I) immunopeptidome. In the ER, these enzymes cooperate in trimming the N-terminal residues from precursors peptides, so as to generate optimal-length antigens to fit into the MHC class I groove. Alteration or loss of ERAPs function significantly modify the repertoire of antigens presented by MHC I molecules, severely affecting the activation of both NK and CD8+ T cells. It is, therefore, conceivable that variations affecting the presentation of pathogen-derived antigens might result in an inadequate immune response and onset of disease. After the first evidence showing that ERAP1-deficient mice are not able to control Toxoplasma gondii infection, a number of studies have demonstrated that ERAPs are control factors for several infectious organisms. In this review we describe how susceptibility, development, and progression of some infectious diseases may be affected by different ERAPs variants, whose mechanism of action could be exploited for the setting of specific therapeutic approaches
Laser-assisted guiding of electric discharges around objects
Electric breakdown in air occurs for electric fields exceeding 34 kV/cm and results in a large current surge that propagates along unpredictable trajectories. Guiding such currents across specific paths in a controllable manner could allow protection against lightning strikes and high-voltage capacitor discharges. Such capabilities can be used for delivering charge to specific targets, for electronic jamming, or for applications associated with electric welding and machining. We show that judiciously shaped laser radiation can be effectively used to manipulate the discharge along a complex path and to produce electric discharges that unfold along a predefined trajectory. Remarkably, such laser-induced arcing can even circumvent an object that completely occludes the line of sight
Does greening of neotropical cities considerably mitigate carbon dioxide emissions? The case of Medellin, Colombia
Cities throughout the world are advocating highly promoted tree plantings as a climate change mitigation measure. Assessing the carbon offsets associated with urban trees relative to other climate change policies is vital for sustainable development, planning, and solving environmental and socio-economic problems, but is difficult in developing countries. We estimated and assessed carbon dioxide (CO2) storage, sequestration, and emission offsets by public trees in the Medellin Metropolitan Area, Colombia, as a viable Nature-Based Solution for the Neotropics. While previous studies have discussed nature-based solutions and explored urban tree carbon dynamics in high income countries, few have been conducted in tropical cities in low-middle income countries, particularly within South America. We used a public tree inventory for the Metropolitan Area of the Aburrá Valley and an available urban forest functional model, i-Tree Streets, calibrated for Colombia's context. We found that CO2 offsets from public trees were not as effective as cable cars or landfills. However, if available planting spaces are considered, carbon offsets become more competitive with cable cars and other air quality and socio-economic co-benefits are also provided. The use of carbon estimation models and the development of relevant carbon accounting protocols in Neotropical cities are also discussed. Our nature-based solution approach can be used to better guide management of urban forests to mitigate climate change and carbon offset accounting in tropical cities lacking available information. © 2017 by the authors
Quantitative determination of asbestos in rocks and soils by optical microscopy: analytical methods and examples of application
Polyaniline (PANI): an innovative support for sampling and removal of VOCs in air matrices
Polyaniline (PANI)-based materials for both removal and sampling of volatile organic compounds (VOCs) from air by rapid adsorption/desorption processes have been developed. The polymer was synthesized in form of emeraldine as both salt and base using different synthetic approaches, a traditional one and a "green" one. VOCs adsorption/desorption efficiency was evaluated for all the materials analyzing the desorbed VOCs fractions by GC/MS technique and obtaining results similar to the presently adopted method employing commercial activated carbon. Most important, in this work it has been demonstrated for the first time that the use of PANI-based sorbents allowed the substitution of the toxic CS2, recommended in official methods, with the less hazardous CH3OH as the VOCs extraction solvent. Moreover, a complete regeneration of the polymers could be realized by a few rapid washing steps. Finally, the best PANI-based material was subjected to recycling tests thereby showing a high adsorption/desorption efficiency retention up to four runs
A New ERAP2/Iso3 Isoform Expression Is Triggered by Different Microbial Stimuli in Human Cells. Could It Play a Role in the Modulation of SARS-CoV-2 Infection?
Following influenza infection, rs2248374-G ERAP2 expressing cells may transcribe an alternative spliced isoform: ERAP2/Iso3. This variant, unlike ERAP2-wt, is unable to trim peptides to be loaded on MHC class I molecules, but it can still dimerize with both ERAP2-wt and ERAP1-wt, thus contributing to profiling an alternative cellular immune-peptidome. In order to verify if the expression of ERAP2/Iso3 may be induced by other pathogens, PBMCs and MDMs isolated from 20 healthy subjects were stimulated with flu, LPS, CMV, HIV-AT-2, SARS-CoV-2 antigens to analyze its mRNA and protein expression. In parallel, Calu3 cell lines and PBMCs were in vitro infected with growing doses of SARS-CoV-2 (0.5, 5, 1000 MOI) and HIV-1BAL (0.1, 1, and 10 ng p24 HIV-1Bal/1
7 106 PBMCs) viruses, respectively. Results showed that: (1) ERAP2/Iso3 mRNA expression can be prompted by many pathogens and it is coupled with the modulation of several determinants (cytokines, interferon-stimulated genes, activation/inhibition markers, antigen-presentation elements) orchestrating the anti-microbial immune response (Quantigene); (2) ERAP2/Iso3 mRNA is translated into a protein (western blot); (3) ERAP2/Iso3 mRNA expression is sensitive to SARS-CoV-2 and HIV-1 concentration. Considering the key role played by ERAPs in antigen processing and presentation, it is conceivable that these enzymes may be potential targets and modulators of the pathogenicity of infectious diseases and further analyses are needed to define the role played by the different isoforms
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