RESUMO
One of the main objectives of the ANTARES telescope is the search for point-like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliable way to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i.e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, the Moon shadow is observed with 3.5 σ statistical significance. The detector angular resolution for downward-going muons is 0 . 73 ∘ ± 0 . 14 ∘ . The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location.
RESUMO
A novel algorithm to reconstruct neutrino-induced particle showers within the ANTARES neutrino telescope is presented. The method achieves a median angular resolution of [Formula: see text] for shower energies below 100 TeV. Applying this algorithm to 6 years of data taken with the ANTARES detector, 8 events with reconstructed shower energies above 10 TeV are observed. This is consistent with the expectation of about 5 events from atmospheric backgrounds, but also compatible with diffuse astrophysical flux measurements by the IceCube collaboration, from which 2-4 additional events are expected. A [Formula: see text] C.L. upper limit on the diffuse astrophysical neutrino flux with a value per neutrino flavour of [Formula: see text] is set, applicable to the energy range from 23 TeV to 7.8 PeV, assuming an unbroken [Formula: see text] spectrum and neutrino flavour equipartition at Earth.
RESUMO
Cornelia de Lange syndrome (CdLS) is a rare multisystem disorder characterized by facial dysmorphisms, upper limb abnormalities, growth and cognitive retardation. About half of all patients with CdLS carry mutations in the NIPBL gene. The first Italian CdLS cohort involving 62 patients (including 4 related members) was screened for NIPBL mutations after a clinical evaluation using a quantitative score that integrates auxological, malformation and neurodevelopmental parameters. The patients were classified as having an overall 'severe', 'moderate' or 'mild' phenotype. NIPBL screening showed 26 mutations so classified: truncating (13), splice-site (8), missense (3), in-frame deletion (1) and regulatory (1). The truncating mutations were most frequently found in the patients with a high clinical score, whereas most of the splice-site and all missense mutations clustered in the low-medium score groups. The NIPBL-negative group included patients covering the entire clinical spectrum. The prevalence of a severe phenotype in the mutated group and a mild phenotype in the non-mutated group was statistically significant. In terms of the isolated clinical signs, the statistically significant differences between the mutation-positive and mutation-negative individuals were pre- and post-natal growth deficits, limb reduction, and delayed speech development. The proposed score seems to be a valuable means of prioritizing the patients with CdLS to undergo an NIPBL mutation test.
Assuntos
Síndrome de Cornélia de Lange/diagnóstico , Síndrome de Cornélia de Lange/genética , Mutação , Proteínas/genética , Adolescente , Adulto , Proteínas de Ciclo Celular , Criança , Pré-Escolar , Estudos de Coortes , Análise Mutacional de DNA , Síndrome de Cornélia de Lange/patologia , Feminino , Humanos , Lactente , Itália , Masculino , Pessoa de Meia-Idade , PrevalênciaRESUMO
Several vaccinia virus early proteins (encoded by genes B1R, H5R and I3L) synthesized in the presence of an inhibitor of DNA synthesis localize, at least in part, to punctate inclusions that are visible by immunofluorescence in the cytoplasm of poxvirus-infected cells. It is shown that these inclusions contain DNA (visualized by DAPI staining of the infected cells) and that the number of inclusions is proportional to the amount of input virus. Their mean diameter (about 680 nm) was larger than that of purified vaccinia virus particles. When the inhibition of DNA synthesis was reversed, incorporation of BrdU into the B1R particles was demonstrated after labelling for 30 min, suggesting that these cytoplasmic focal sites correspond to viral DNA replication complexes that have initiated normally but are inhibited at the step of DNA chain elongation. These experiments suggest strongly that these inclusions are the precursors of the virosomes.
Assuntos
DNA Viral/biossíntese , Corpos de Inclusão Viral/metabolismo , Precursores de Proteínas/metabolismo , Vaccinia virus/metabolismo , Proteínas Virais/metabolismo , Animais , Linhagem Celular , Proteínas de Ligação a DNA/metabolismo , Imunofluorescência , Hidroxiureia/metabolismo , Vaccinia virus/crescimento & desenvolvimento , Vírion/metabolismoRESUMO
In order to study the activity of a hammerhead ribozyme in a cytoplasmic environment. HeLa cells infected with a recombinant vaccinia virus expressing T7 RNA polymerase were contransfected with plasmids expressing the ribozyme and its target RNA (nucleotides (nt) +1 to +692 of HIV-1 RNA) under the control of a T7 promoter. Two ribozyme-containing plasmids were designed to express RNAs of respectively 181 nt (Rz181) and 132 nt (Rz132). The sequence of each of these RNAs contained a 35 nt hammerhead ribozyme which is known to cleave its minimal 14-mer RNA substrate efficiently in vitro at a site corresponding to position +115 of the HIV-1 RNA. Control transfections were carried out with the parental plasmid pET3, which expressed a 134 nt RNA lacking the ribozyme sequence, and also with a plasmid expressing a 181 nt RNA (Rz181M) containing a single mutation known to inactivate the in vitro cleavage activity of the ribozyme. As detected by RT-PCR, the amount of target RNA was reproducibly reduced at a ribozyme/target ratio higher than 50 with Rz181 and Rz132 whereas it remained unaffected with Rz181M, thus eliminating the possibility of antisense inhibition. Rz132 proved to be more efficient than Rz181. Competitive RT-PCR indicated that, at ribozyme/target ratio of 300, the amount of residual target RNA was reduced by approximately 85% in the presence of Rz181. In contrast to these in vivo effects, Rz181 and Rz132 obtained by in vitro transcription were inactive against the minimal 14 mer (or longer) substrate under a variety of conditions. In conclusion, although in vitro studies of ribozymes are essential to learn their catalytic mechanism, they cannot be used to predict the efficiency of RNAs containing a ribozyme sequence when it is expressed in cells.
Assuntos
HIV-1/genética , RNA Catalítico/metabolismo , RNA Viral/metabolismo , Transcrição Gênica , Citoplasma/metabolismo , Células HeLa , Humanos , Técnicas In Vitro , Conformação de Ácido Nucleico , Plasmídeos , Reação em Cadeia da Polimerase , RNA Catalítico/química , RNA Viral/químicaRESUMO
The thymidine analogue 4-thiothymidine (s4T) strongly absorbs light at wavelengths in the UVA range (lambda max 335 nm) and we have examined the photoinactivation of vaccinia and herpes simplex viruses grown in the presence of this nucleoside. The cells used in this study (Vero, mouse 1D-TK+) were able to grow at the same rate when cultured in the presence of 2 mM s4T or 2 mM thymidine, albeit at a slower rate than control cells. Consistent with this finding, viruses grown in the presence of 1-4 mM s4T were obtained in reduced yield but retained full infectivity. Both viruses were specifically inactivated by irradiation with 365 nm light and their photosensitivity, as measured by the initial slope of the inactivation curve, increased in parallel with the concentration of s4T added to the culture medium. More than 90% of vaccinia virus grown in the presence of 4 mM s4T was inactivated. Organomercurial agarose chromatography of sheared DNA isolated from vaccinia virus grown in the presence of 2 mM s4T showed that approximately 2.5% of DNA fragments were specifically retained, as compared to 0.2% for control DNA. This value corresponds to at least one s4T residue incorporated per 30,000 nucleotides of vaccinia virus DNA. In fact, it is likely that this ratio is actually approximately 10 times higher because of the incomplete retention of control thiolated oligodeoxynucleotides.(ABSTRACT TRUNCATED AT 250 WORDS)