392 research outputs found
Native NIR-emitting single colour centres in CVD diamond
Single-photon sources are a fundamental element for developing quantum
technologies, and sources based on colour centres in diamonds are among the
most promising candidates. The well-known NV centres are characterized by
several limitations, thus few other defects have recently been considered. In
the present work, we characterize in detail native efficient single colour
centres emitting in the near infra-red in both standard IIa single-crystal and
electronic-grade polycrystalline commercial CVD diamond samples. In the former
case, a high-temperature annealing process in vacuum is necessary to induce the
formation/activation of luminescent centres with good emission properties,
while in the latter case the annealing process has marginal beneficial effects
on the number and performances of native centres in commercially available
samples. Although displaying significant variability in several photo physical
properties (emission wavelength, emission rate instabilities, saturation
behaviours), these centres generally display appealing photophysical properties
for applications as single photon sources: short lifetimes, high emission rates
and strongly polarized light. The native centres are tentatively attributed to
impurities incorporated in the diamond crystal during the CVD growth of
high-quality type IIa samples, and offer promising perspectives in
diamond-based photonics.Comment: 27 pages, 10 figures. Submitted to "New Journal of Phsyics",
NJP-100003.R
SARS-CoV-2 Mproinhibition by a zinc ion: structural features and hints for drug design
The first structure of the SARS-CoV-2 main protease in complex with an isolated zinc ion provides solid ground for the design of potent and selective metal-conjugated inhibitors
Efficacy of a U-shaped automatic electric toothbrush in dental plaque removal: A cross-over randomized controlled trial
Postpubertal effects of the rapid maxillary expansion and facial mask versus the removable mandibular retractor for the early treatment of class iii malocclusion: A study on lateral cephalograms
The aim of this study was to compare the efficacy of early treatment of Class III malocclusions with rapid maxillary expansion (RME) and facial mask (FM) versus the removable mandibular retractor (RMR) re-evaluated at a postpubertal observation on lateral cephalograms. All prepubertal patients with Class III malocclusion treated consecutively from 1986 to 2013 by means of RME/FM or RMR were analyzed. Twenty-nine patients treated with RME/FM therapy and 23 patients treated with RMR were selected. Lateral cephalograms were available at 3 time points, before treatment (T1), at the end of active treatment (T2), and at a postpubertal observation (T3). Statistical comparisons were performed with independent sample t tests or Mann–Whitney tests. During the T1–T3 interval, a significantly greater maxillary protraction (SNA +1.5 mm, p = 0.031) and significantly greater improvements in ANB and Wits appraisal (+1.9 degrees, p = 0.002, and +2.2 mm, p = 0.012, respectively) were recorded in the RME/FM group. No statistically significant changes could be found in vertical skeletal measurements. In the dentoalveolar region, the RME/FM group showed a significantly greater correction of the molar relationship (−1.5 mm, p = 0.021). Early treatment of Class III malocclusion with RME/FM protocol in comparison with RMR protocol showed a greater maxillary advancement and greater improvements in sagittal skeletal Class III relationships
A representation theorem for MV-algebras
An {\em MV-pair} is a pair where is a Boolean algebra and is
a subgroup of the automorphism group of satisfying certain conditions. Let
be the equivalence relation on naturally associated with . We
prove that for every MV-pair , the effect algebra is an MV-
effect algebra. Moreover, for every MV-effect algebra there is an MV-pair
such that is isomorphic to
A quantum logical and geometrical approach to the study of improper mixtures
We study improper mixtures from a quantum logical and geometrical point of
view. Taking into account the fact that improper mixtures do not admit an
ignorance interpretation and must be considered as states in their own right,
we do not follow the standard approach which considers improper mixtures as
measures over the algebra of projections. Instead of it, we use the convex set
of states in order to construct a new lattice whose atoms are all physical
states: pure states and improper mixtures. This is done in order to overcome
one of the problems which appear in the standard quantum logical formalism,
namely, that for a subsystem of a larger system in an entangled state, the
conjunction of all actual properties of the subsystem does not yield its actual
state. In fact, its state is an improper mixture and cannot be represented in
the von Neumann lattice as a minimal property which determines all other
properties as is the case for pure states or classical systems. The new lattice
also contains all propositions of the von Neumann lattice. We argue that this
extension expresses in an algebraic form the fact that -alike the classical
case- quantum interactions produce non trivial correlations between the
systems. Finally, we study the maps which can be defined between the extended
lattice of a compound system and the lattices of its subsystems.Comment: submitted to the Journal of Mathematical Physic
Preoperative distraction in children: hand-held videogames vs clown therapy.
Anxiety in children undergoing surgery is characterized by feelings of tension, apprehension, nervousness and fear which may manifest differently. Postoperative behavioural changes such as nocturnal enuresis, feeding disorders, apathy, and sleep disturbances may stem from postoperative anxiety. Some Authors pointed out that over 60% of children undergoing surgery are prone to developing behavioural alterations 2 weeks after surgery. Variables such as age, temperament and anxiety both in children and parents are considered predictors of such changes.1 Studies were published describing how psycho-behavioural interventions based on play, learning and entertainment in preparing children for surgery, may reduce preoperative anxiety. Clown-therapy is applied in the most important paediatric facilities and has proved to diminish children's emotional distress and sufferance, as well as consumption of both analgesics and sedatives and to facilitate the achievement of therapeutic goals. The aim of our study was to evaluate the efficacy of clown-therapy during the child's hospital stay, with a view to optimizing treatment and care, preventing behavioural alterations and enhancing the child's overall life quality
CA-IX-Expressing Small Extracellular Vesicles (sEVs) Are Released by Melanoma Cells under Hypoxia and in the Blood of Advanced Melanoma Patients
Cutaneous melanoma is a highly aggressive skin cancer, with poor prognosis. The tumor microenvironment is characterized by areas of hypoxia. Carbonic anhydrase IX (CA-IX) is a marker of tumor hypoxia and its expression is regulated by hypoxia-inducible factor-1 (HIF-1). CA-IX has been found to be highly expressed in invasive melanomas. In this study, we investigated the effects of hypoxia on the release of small extracellular vesicles (sEVs) in two melanoma in vitro models. We demonstrated that melanoma cells release sEVs under both normoxic and hypoxic conditions, but only hypoxia-induced sEVs express CA-IX mRNA and protein. Moreover, we optimized an ELISA assay to provide evidence for CA-IX protein expression on the membranes of the sEVs. These CA-IX-positive sEVs may be exploited as potential biomarkers for liquid biopsy
Effect of water level on migratory birds habitat at lake maggiore
Migratory birds need to stop along their route to rest and feed at so called stopover sites. "Bolle di Magadino"is a protected wetland located near lake Maggiore (CH), an internationally recognized nesting and stop-over site for birds. The waters of Lake Maggiore are important resources for multiple usages, and are artificially regulated through a dam. Even slight variations in the water level are sufficient to cause flooding and draining of large portions of the wetlands, affecting foraging and resting opportunities for birds. We use open data and FOSS4G to study the effect of water level on bird migration. We compared the extent and type of flooded habitat using two approaches: Sentinel-1 remote sensing imagery and simulations based on the measured water level. The effect of type and extent of submerged vegetation obtained with both methods was tested against a time series of bird captures. Both methods had a similar temporal pattern of flooding in autumn, but nearly opposite in spring. The total extent and the type of submerged habitats showed significant differences. The results obtained by simulations based on water level were more correlated to birds captures and species richness than the estimations of flooded habitat derived by with Sentinel-1. The results presented here will contribute to the definition sustainable management tools of water management of lake Maggiore taking into account the effect of lake level on biodiversity
Solar UV-B Radiation Influences Carotenoid Accumulation of Tomato Fruit through Both Ethylene-Dependent and -independent Mechanisms
The effect of UV-B shielding on ethylene production in ripening tomato fruits and the contribution of
ethylene and UV-B radiation on carotenoid accumulation and profile during ripening were assessed
to get more insight about the interplay between these two regulatory factors. To this aim, rin and nor
tomato mutants, unable to produce ripening ethylene, and cv Ailsa Craig were cultivated under
control or UV-B depleted conditions until full fruit ripening. The significantly decreased ethylene
evolution following UV-B depletion, evident only in Ailsa Craig, suggested the requirement of
functional rin and nor genes for UVB-mediated ethylene production. Carotenoid content and profile
were found to be controlled by both ethylene and UV-B radiation. This latter influenced carotenoid
metabolism either in an ethylene-dependent or -independent way, as indicated by UVB-induced
changes also in nor and rin carotenoid content and confirmed by correlation plots between ethylene
evolution and carotenoid accumulation performed separately for control and UV-B shielded fruits. In
conclusion, natural UV-B radiation influences carotenoid metabolism in a rather complex way,
involving ethylene-dependent and -independent mechanisms, which seem to act in an antagonistic
way
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