117 research outputs found
The ESQUIRE project: Quantum Dots as scintillation detectors
The primary goal of ESQUIRE (Experiment with Scintillating
Quantum dots for Ionizing Radiation Events) is the development of a new family of scintillation detectors based on scintillating nanocrystals coupled to high-quantumefficiency solid-state detectors. These detectors will be designed for the search of neutrinoless double-beta decay (0νββ), therefore an excellent energy resolution in
the region of interest for the study of 0νββ (∼2% around 3 MeV) is mandatory. One of the main advantages in this approach is the easy mass scalability, which makes ESQUIRE a competitive option for next-generation experiments. During the discussion the project goal will be presented, alongside the first optical characterization of QD samples
Detection of human metapneumovirus and respiratory syncytial virus by real-time polymerase chain reaction among hospitalized young children in Iran
Background: Acute respiratory infection plays an important role in hospitalization of children in developing countries; detection of viral causes in such infections is very important. The respiratory syncytial virus (RSV) is the most common etiological agent of viral lower respiratory tract infection in children, and human metapneumovirus (hMPV) is associated with both upper and lower respiratory tract infections among infants and children. Objectives: This study evaluated the frequency and seasonal prevalence of hMPV and RSV in hospitalized children under the age of five, who were admitted to Aliasghar children�s hospital of Iran University of Medical Sciences from March 2010 until March 2013. Patients and Methods: Nasopharyngeal or throat swabs from 158 hospitalized children with fever and respiratory distress were evaluated for RSV and hMPV RNA by the real-time polymerase chain reaction (PCR) method. Results: Among the 158 children evaluated in this study, 49 individuals (31.1) had RSV infection while nine individuals (5.7) had hMPV infection. Five (55.5) of the hMPV-infected children were male while four (44.5) were female and 27 (55.2) of the RSV-infected patients were females and 22 (44.8) were males. The RSV infections were detected in mainly one year old children. Both RSV and hMPV infections had occurred mainly during winter and spring seasons. Conclusions: Respiratory syncytial virus was the major cause of acute respiratory infection in children under one-year of age while human metapneumovirus had a low prevalence in this group. The seasonal occurrence of both viruses was the same. © 2016, Ahvaz Jundishapur University of Medical Sciences
Amyloid β induces early changes in the ribosomal machinery, cytoskeletal organization and oxidative phosphorylation in retinal photoreceptor cells
Amyloid β (Aβ) accumulation and its aggregation is characteristic molecular feature of the development of Alzheimer’s disease (AD). More recently, Aβ has been suggested to be associated with retinal pathology associated with AD, glaucoma and drusen deposits in age related macular degeneration (AMD). In this study, we investigated the proteins and biochemical networks that are affected by Aβ in the 661 W photoreceptor cells in culture. Time and dose dependent effects of Aβ on the photoreceptor cells were determined utilizing tandem mass tag (TMT) labeling-based quantitative mass-spectrometric approach. Bioinformatic analysis of the data revealed concentration and time dependent effects of the Aβ peptide stimulation on various key biochemical pathways that might be involved in mediating the toxicity effects of the peptide. We identified increased Tau phosphorylation, GSK3β dysregulation and reduced cell viability in cells treated with Aβ in a dose and time dependent manner. This study has delineated for the first-time molecular networks in photoreceptor cells that are impacted early upon Aβ treatment and contrasted the findings with a longer-term treatment effect. Proteins associated with ribosomal machinery homeostasis, mitochondrial function and cytoskeletal organization were affected in the initial stages of Aβ exposure, which may provide key insights into AD effects on the photoreceptors and specific molecular changes induced by Aβ peptide
TESTING THE PAULI EXCLUSION PRINCIPLE IN THE COSMIC SILENCE
The VIP Collaboration is performing high precision tests of the Pauli Exclusion Principle for electrons in the extremely low cosmic background environment of the Underground Gran Sasso Laboratories of INFN (Italy). The experimental technique consists in introducing a DC current in a copper conductor, searching for K PEP-forbidden atomic transitions when the K shell is already occupied by two electrons. VIP set an upper limit on the PEP-violation probability . The aim of the upgraded VIP-2 experiment is to improve this result at least by two orders of magnitude. The improved experimental setup and the results of a preliminary data analysis, corresponding to the the first run of the VIP-2 data taking (2016–2017), will be presented
VIP2 in LNGS - Testing the Pauli Exclusion Principle for electrons with high sensitivity
The VIP2 (VIolation of the Pauli Exclusion Principle) experiment at the Gran Sasso underground laboratory (LNGS) is searching for possible violations of standard quantum mechanics predictions in atoms at very high sensitivity. We investigate atomic transitions with precision X-ray spectroscopy in order to test the Pauli Exclusion Principle (PEP) and therefore the related spin-statistics theorem. We will present our experimental method for the search for "anomalous" (i.e. Pauli-forbidden) X-ray transitions in copper atoms, produced by "new" electrons, which could have tiny probability to undergo Pauli-forbidden transition to the ground state already occupied by two electrons. We will describe the VIP2 experimental setup, which is taking data at LNGS presently. The goal of VIP2 is to test the PEP for electrons with unprecedented accuracy, down to a limit in the probability that PEP is violated at the level of 10−31. We will present current experimental results and discuss implications of a possible violation
The kaonic atoms research program at DA{\Phi}NE: from SIDDHARTA to SIDDHARTA-2
The interaction of antikaons with nucleons and nuclei in the low-energy
regime represents an active research field in hadron physics with still many
important open questions. The investigation of light kaonic atoms, in which one
electron is replaced by a negatively charged kaon, is a unique tool to provide
precise information on this interaction; the energy shift and the broadening of
the low-lying states of such atoms, induced by the kaon-nucleus hadronic
interaction, can be determined with high precision from the atomic X-ray
spectroscopy, and this experimental method provides unique information to
understand the low energy kaon-nucleus interaction at the production threshold.
The lightest atomic systems, like the kaonic hydrogen and the kaonic deuterium
deliver, in a model-independent way, the isospin-dependent kaon-nucleon
scattering lengths. The most precise kaonic hydrogen measurement to-date,
together with an exploratory measurement of kaonic deuterium, were carried out
in 2009 by the SIDDHARTA collaboration at the DA{\Phi}NE electron-positron
collider of LNF-INFN, combining the excellent quality kaon beam delivered by
the collider with new experimental techniques, as fast and very precise X-ray
detectors, like the Silicon Drift Detectors. The SIDDHARTA results triggered
new theoretical work, which achieved major progress in the understanding of the
low-energy strong interaction with strangeness reflected by the
antikaon-nucleon scattering lengths calculated with the antikaon-proton
amplitudes constrained by the SIDDHARTA data. The most important open question
is the experimental determination of the hadronic energy shift and width of
kaonic deuterium; presently, a major upgrade of the setup, SIDDHARTA-2, is
being realized to reach this goal. In this paper, the results obtained in 2009
and the proposed SIDDHARTA-2 upgrades are presented
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