317 research outputs found
Experimental achievement of the entanglement assisted capacity for the depolarizing channel
We experimentally demonstrate the achievement of the entanglement assisted
capacity for classical information transmission over a depolarizing channel.
The implementation is based on the generation and local manipulation of 2-qubit
Bell states, which are finally measured at the receiver by a complete Bell
state analysis. The depolarizing channel is realized by introducing quantum
noise in a controlled way on one of the two qubits. This work demonstrates the
achievement of the maximum allowed amount of information that can be shared in
the presence of noise and the highest reported value in the noiseless case.Comment: 4 pages, 3 figure
Hybrid coupling of CG and HDG discretizations based on Nitsche’s method
This is a post-peer-review, pre-copyedit version of an article published in Computational mechanics. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00466-019-01770-8A strategy to couple continuous Galerkin (CG) and hybridizable discontinuous Galerkin (HDG) discretizations based only on the HDG hybrid variable is presented for linear thermal and elastic problems. The hybrid CG-HDG coupling exploits the definition of the numerical flux and the trace of the solution on the mesh faces to impose the transmission conditions between the CG and HDG subdomains. The con- tinuity of the solution is imposed in the CG problem via Nitsche’s method, whereas the equilibrium of the flux at the interface is naturally enforced as a Neumann con- dition in the HDG global problem. The proposed strategy does not affect the core structure of CG and HDG discretizations. In fact, the resulting formulation leads to a minimally-intrusive coupling, suitable to be integrated in existing CG and HDG libraries. Numerical experiments in two and three dimensions show optimal global convergence of the stress and superconvergence of the displacement field, locking-free approximation, as well as the potential to treat structural problems of engineering interest featuring multiple materials with compressible and nearly incompressible behaviors.Peer ReviewedPostprint (author's final draft
Characteristics of Compost Obtained from Winemaking Byproducts
A model procedure for the sustainable management of plant biomass related to wine production, namely vine branches from agricultural practices in the vineyard and marcs remaining after grapes crushing, was devised. An artificial humification process was set up that could respond to the needs of environmental sustainability and could be a safe way to be reintroduce in the vineyard part of the organic matter previously exported, thus contributing to recover or maintain vineyard soil fertility. Two different strategies for composting were tested, namely a static pile, made by branches and marcs, and a pile that was fed twice a year alternatively with vine branches and grape marcs. The experimentation lasted 710 days, during which environmental parameters, i.e. temperature and rainfalls were monitored. Growth dynamics of the principal functional groups of microorganism were followed. A characterization of the composted material was obtained by measuring several parameters among which, pH, carbon, nitrogen, sulfur and heavy metals content. The characteristics of the produced compost fulfill the requirements prescribed by the Italian legislation regarding the use of compost as soil amendment. Germination tests demonstrated the absence of phytotoxicity and conversely evidenced a stimulating activity towards root development
Pharmacotherapies targeted to neurogenesis in order to rescue cognitive performance in Down syndrome
Down syndrome (DS) is a genetic condition caused by the triplication of chromosome 21. The most invalidating feature of DS is intellectual disability (ID). Neurogenesis and dendritic maturation impairment are key determinants of ID in DS. To study DS, several mouse models have been created and the most used is the Ts65Dn mouse. Despite intense efforts, there are currently no therapies for DS. Considering the time course of brain development, pharmacotherapies should be carried as early as possible during the lifespan.
The goal of this project was to establish whether neonatal treatment with “unexplored” molecules restores the major neurodevelopmental defects and cognitive performance in the Ts65Dn mouse model and whether their effect is retained after treatment cessation.
I have explored the effects of different molecules administered to Ts65Dn mice during the neonatal period. ELND006, an inhibitor of γ-secratase. ELND006 blocks the formation of a small APP-derived peptide which inhibits the activity of the SHH pathway, thereby reducing neurogenesis. EGCG, a natural inhibitor of the kinase DYRK1A, whose overactivity in the DS brain negatively affects neurogenesis. 7,8-DHF, a natural mimetic of BDNF that by activating the TRKB receptor may compensate for the reduced levels of BDNF in the DS brain.
ELND006 restored neurodevelopment of the hippocampal formation of Ts65Dn mice, and most of these effects were retained at one month after treatment cessation. EGCG had short-term but not long-term effects on hippocampal development and behavior. 7,8-DHF administered neonatally caused restoration of hippocampal development. Moreover, administration of 7,8-DHF from postnatal day 3 to adolescence led to a restoration of memory.
These demonstrations may stimulate the design of clinical trials in DS with the molecule/s with the highest efficacy and the safest profile. This is the challenge that faces the community of preclinical researchers interested in DS: to transform a dream into reality
A weakly compressible hybridizable discontinuous Galerkin formulation for fluid-structure interaction problems
A scheme for the solution of fluid-structure interaction (FSI) problems with
weakly compressible flows is proposed in this work. A novel hybridizable
discontinuous Galerkin (HDG) method is derived for the discretization of the
fluid equations, while the standard continuous Galerkin (CG) approach is
adopted for the structural problem. The chosen HDG solver combines robustness
of discontinuous Galerkin (DG) approaches in advection-dominated flows with
higher order accuracy and efficient implementations. Two coupling strategies
are examined in this contribution, namely a partitioned Dirichlet-Neumann
scheme in the context of hybrid HDG-CG discretizations and a monolithic
approach based on Nitsche's method, exploiting the definition of the numerical
flux and the trace of the solution to impose the coupling conditions. Numerical
experiments show optimal convergence of the HDG and CG primal and mixed
variables and superconvergence of the postprocessed fluid velocity. The
robustness and the efficiency of the proposed weakly compressible formulation,
in comparison to a fully incompressible one, are also highlighted on a
selection of two and three dimensional FSI benchmark problems.Comment: 49 pages, 20 figures, 2 table
Explorations of the viability of ARM and Xeon Phi for physics processing
We report on our investigations into the viability of the ARM processor and
the Intel Xeon Phi co-processor for scientific computing. We describe our
experience porting software to these processors and running benchmarks using
real physics applications to explore the potential of these processors for
production physics processing.Comment: Submitted to proceedings of the 20th International Conference on
Computing in High Energy and Nuclear Physics (CHEP13), Amsterda
Impaired Assembly Results in the Accumulation of Multiple HLA-C Heavy Chain Folding Intermediates
AbstractClass I MHC H chains assemble with β2-microglobulin (β2m) and are loaded with peptide Ags through multiple folding steps. When free of β2m, human H chains react with Abs to linear epitopes, such as L31. Immunodepletion and coimmunoprecipitation experiments, performed in this study, detected a preferential association of L31-reactive, β2m-free H chains with calnexin in β2m-defective cells, and with calreticulin and TAP in β2m-expressing cells. In β2m-defective cells, the accumulation of calnexin-bound H chains stoichiometrically exceeded their overall accumulation, a finding that supports both chaperoning preferences and distinct sorting abilities for different class I folds. No peptide species, in a mass range compatible with that of the classical class I ligands, could be detected by mass spectrometry of acidic eluates from L31-reactive HLA-Cw1 H chains. In vitro assembly experiments in TAP-defective T2 cells, and in cells expressing an intact Ag-processing machinery, demonstrated that L31 H chains are not only free of, but also unreceptive to, peptides. L31 and HC10, which bind nearly adjacent linear epitopes of the α1 domain α helix, reciprocally immunodepleted free HLA-C H chains, indicating the existence of a local un-/mis-folding involving the N-terminal end of the α1 domain α helix and peptide-anchoring residues of the class I H chain. Thus, unlike certain murine free H chains, L31-reactive H chains are not the immediate precursors of conformed class I molecules. A model inferring their precursor-product relationships with other known class I intermediates is presented
Leukocyte Integrin Antagonists as a Novel Option to Treat Dry Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a complex multifactorial degenerative disease
that leads to irreversible blindness. AMD affects the macula, the central part of the retina
responsible for sharp central vision. Retinal pigment epithelium (RPE) is the main cellular
type affected in dry AMD. RPE cells form a monolayer between the choroid and the
neuroretina and are in close functional relationship with photoreceptors; moreover, RPE
cells are part of the blood retina barrier that is disrupted in ocular diseases such as AMD.
During ocular inflammation lymphocytes and macrophages are recruited, contact RPE and
produce pro-inflammatory cytokines, which play an important role in AMD pathogenesis.
The interaction between RPE and immune cells is mediated by leukocyte integrins,
heterodimeric transmembrane receptors, and adhesion molecules, including VCAM-1
and ICAM-1. Within this frame, this study aimed to characterize RPE-leukocytes
interaction and to investigate any potentially beneficial effects induced by integrin
antagonists (DS-70, MN27 and SR714), developed in previous studies. ARPE-19 cells
were co-cultured for different incubation times with Jurkat cells and apoptosis and
necrosis levels were analyzed by flow cytometry. Moreover, we measured the mRNA
levels of the pro-inflammatory cytokine IL-1\u3b2 and the expression of adhesion molecules
VCAM-1 and ICAM-1. We found that RPE-lymphocyte interaction increased apoptosis
and necrosis levels in RPE cells and the expression of IL-1\u3b2. This interaction was mediated
by the binding of \u3b14\u3b21 and \u3b1L\u3b22 integrins to VCAM-1 and ICAM-1, respectively. The
blockade of RPE-lymphocyte interaction with blocking antibodies highlighted the pivotal
role played by integrins. Therefore, \u3b14\u3b21 and \u3b1L\u3b22 integrin antagonists were employed to
disrupt RPE-lymphocyte crosstalk. Small molecule integrin antagonists proved to be
effective in reducing RPE cell death and expression of IL-1\u3b2, demonstrating that integrin
antagonists could protect RPE cells from detrimental effects induced by the interaction
with immune cells recruited to the retina. Overall, the leukocyte integrin antagonists
employed in the present study may represent a novel opportunity to develop new
drugs to fight dry AMD
Emerging Approaches of Transcatheter Valve Repair/Insertion
Aortic stenosis (AS) and mitral regurgitation (MR) account for the majority of valvular diseases and their prevalence is increasing according to increased life expectancy. Surgical treatment is the gold standard, although operative risk may be high in some patients due to comorbidities and age. A large part of the patients at high surgical risk who could beneficiate of treatment are not referred to surgery. Therefore, there is a need of alternative and less invasive procedures
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