18 research outputs found
Revealing the electronic structure of a carbon nanotube carrying a supercurrent
Carbon nanotubes (CNTs) are not intrinsically superconducting but they can
carry a supercurrent when connected to superconducting electrodes. This
supercurrent is mainly transmitted by discrete entangled electron-hole states
confined to the nanotube, called Andreev Bound States (ABS). These states are a
key concept in mesoscopic superconductivity as they provide a universal
description of Josephson-like effects in quantum-coherent nanostructures (e.g.
molecules, nanowires, magnetic or normal metallic layers) connected to
superconducting leads. We report here the first tunneling spectroscopy of
individually resolved ABS, in a nanotube-superconductor device. Analyzing the
evolution of the ABS spectrum with a gate voltage, we show that the ABS arise
from the discrete electronic levels of the molecule and that they reveal
detailed information about the energies of these levels, their relative spin
orientation and the coupling to the leads. Such measurements hence constitute a
powerful new spectroscopic technique capable of elucidating the electronic
structure of CNT-based devices, including those with well-coupled leads. This
is relevant for conventional applications (e.g. superconducting or normal
transistors, SQUIDs) and quantum information processing (e.g. entangled
electron pairs generation, ABS-based qubits). Finally, our device is a new type
of dc-measurable SQUID
An outbreak of Legionnaires’s disease occurred in an area of northwestern Italy
Background: Legionella pneumophila (LP) is recognized as a cause of atypical pneumonia known as
Legionnaires’ disease (LD). The incubation period of LD is typically 5–6 days (range 2-10 days)
following exposure to aerosolized water containing the bacteria. Sporadic cases and large outbreaks
of LD are reported worldwide. Numerous large outbreaks of LD have been reported typically
associated with cooling towers, which distribute aerosolized plumes to relatively large areas. The
present study reports an outbreak of LD occurred in Parma, Northern Italy, spanning over a 2-month
period.
Material/methods: From 27th August to 11th November 2016, 504 urine samples were examined for
the direct detection of LP serogroup 1 antigen by immunocromatographic (Alere BinaxNOW Legionella
Urinary Antigen Card – Alere, USA) and/or immunofluorescence (Sofia Legionella FIA – Quidel, USA)
assays. When a positive result was observed by the urine antigen test (UAT), a respiratory specimen
for direct detection of microorganism by conventional culture and/or molecular method (Allplex
Respiratory Panel 4 – Seegene, Korea) and serum samples for antibodies evaluation by indirect
immunofluorescence (Legionella IFA – Focus Diagnostics, USA) were required.
Results: Since 27th August when the first LP positive urine sample was reported in a 56-year-old
woman, a total of fifty-one of the 504 analyzed samples were positive for the LP antigen. In particular,
these positive samples belonged to 22 females (aged 27–97, median age 69) and 29 males (aged 41-
87, median 68). In the majority of the cases (29), these patients lived in the south-east district of the
town or attended the same area for working or family reasons. Two patients with concomitant
pathologies died. Only in 5 cases, respiratory specimens were sent to the laboratory: 4 (collected 10-
13 days after UAT) were negative and 1 (collected one day after UAT) was positive only for LP DNA.
For 39 patients, at least a serum sample was analyzed for the detection of antibodies: 12 were
negative, 16 had a titre ranging from 1:16 to 1:64 and 11 a titre > 1/64; in 5 cases, it was possible to
reveal a seroconversion. In the same period, LP serogroup 1-8 antibodies were detected (titre ≥ 1:256)
for 3 additional patients living in the epidemic area.
Conclusions: This report describes an outbreak of LD involving 54 patients 32 of which were
geographically related to a district of Parma. Unfortunately, till now, the source of infection is unknown.
Legionellosis outbreaks, frequently observed during season changes, can be difficult to identify; thus,
the timely identification and prevention are crucial for the management of the cases and the attention
for Legionella -associated disease should be maintained at high level
Time-kinetic study of repigmentation in vitiligo patients by tacrolimus or pimecrolimus.
SCOPUS: ar.jinfo:eu-repo/semantics/publishe