69 research outputs found
Topological acoustics in coupled nanocavity arrays
The Su-Schrieffer-Heeger (SSH) model is likely the simplest one-dimensional
concept to study non-trivial topological phases and topological excitations.
Originally developed to explain the electric conductivity of polyacetylene, it
has become a platform for the study of topological effects in electronics,
photonics and ultra-cold atomic systems. Here, we propose an experimentally
feasible implementation of the SSH model based on coupled one-dimensional
acoustic nanoresonators working in the GHz-THz range. In this simulator it is
possible to implement different signs in the nearest neighbor interaction
terms, showing full tunability of all parameters in the SSH model. Based on
this concept we construct topological transition points generating nanophononic
edge and interface states and propose an easy scheme to experimentally probe
their spatial complex amplitude distribution directly by well-established
optical pump-probe techniques.Comment: 10 pages, 4 figure
A virtual reality exposure therapy for PTSD patients controlled by a fuzzy logic system
This paper describes the main characteristics of two integrated systems that explore Virtual Reality technology and Fuzzy Logic to support and to control the assessment of people with Post-Traumatic Stress Disorder during the Virtual Reality Exposure Therapy. The integration of different technologies, the development methodology and the test procedures are described throughout the paper.Peer Reviewe
Brillouin Scattering in Hybrid Optophononic Bragg Micropillar Resonators at 300 GHz
We introduce a monolithic Brillouin generator based on a semiconductor
micropillar cavity embedding a high frequency nanoacoustic resonator operating
in the hundreds of GHz range. The concept of two nested resonators allows an
independent design of the ultrahigh frequency Brillouin spectrum and of the
optical device. We develop an optical free-space technique to characterize
spontaneous Brillouin scattering in this monolithic device and propose a
measurement protocol that maximizes the Brillouin generation efficiency in the
presence of optically induced thermal effects. The compact and versatile
Brillouin generator studied here could be readily integrated into fibered and
on-chip architectures.Comment: 9 pages, 4 figure
Multifractal analysis of the electronic states in the Fibonacci superlattice under weak electric fields
Influence of the weak electric field on the electronic structure of the
Fibonacci superlattice is considered. The electric field produces a nonlinear
dynamics of the energy spectrum of the aperiodic superlattice. Mechanism of the
nonlinearity is explained in terms of energy levels anticrossings. The
multifractal formalism is applied to investigate the effect of weak electric
field on the statistical properties of electronic eigenfunctions. It is shown
that the applied electric field does not remove the multifractal character of
the electronic eigenfunctions, and that the singularity spectrum remains
non-parabolic, however with a modified shape. Changes of the distances between
energy levels of neighbouring eigenstates lead to the changes of the inverse
participation ratio of the corresponding eigenfunctions in the weak electric
field. It is demonstrated, that the local minima of the inverse participation
ratio in the vicinity of the anticrossings correspond to discontinuity of the
first derivative of the difference between marginal values of the singularity
strength. Analysis of the generalized dimension as a function of the electric
field shows that the electric field correlates spatial fluctuations of the
neighbouring electronic eigenfunction amplitudes in the vicinity of
anticrossings, and the nonlinear character of the scaling exponent confirms
multifractality of the corresponding electronic eigenfunctions.Comment: 10 pages, 9 figure
Nursing Care of Patients With Cirrhosis: The LiverHope Nursing Project
Cirrhosis is a complex disease that is associated with disturbances in different organs besides the liver, including kidneys, heart, arterial circulation, lungs, gut, and brain. As a consequence, patients develop a number of complications that result in frequent hospital admissions and high morbidity and mortality. Patients with cirrhosis require constant and rigorous monitoring both in and outside the hospital. In this context, the role of nurses in the care of patients with cirrhosis has not been sufficiently emphasized and there is very limited information about nursing care of patients with cirrhosis compared with other chronic diseases. The current article provides a review of nursing care for the different complications of patients with cirrhosis. Nurses with specific knowledge on liver diseases should be incorporated into multidisciplinary teams managing patients with cirrhosis, both inpatient and outpatient. Conclusion: Nurses play an important role in the management and prevention of complications of the disease and improvement in patients’ quality of life and bridge the gap between clinicians and families, between primary care and hospital care, and provide medical education to patients and caregivers
Efeito de diferentes doses de ácido retinoico sobre a resistência óssea de ratos jovens
SERPINA1 Gene Promoter Is Differentially Methylated in Peripheral Blood Mononuclear Cells of Pregnant Women
SERine Protein INhibitor-A1 (SERPINA1) is an inducible blood cell gene coding for alpha1-antitrypsin (AAT), a plasma protease inhibitor whose circulating levels are raised during inflammation, infection and advanced pregnancy. DNA methylation has been suggested to play a role in SERPINA1 gene expression regulation in peripheral blood mononuclear cells (PBMCs). The methylation status of SERPINA1 in PBMCs is unknown. The aim of this study was to evaluate the methylation profile of the SERPINA1 promoter in PBMC. To this purpose PBMCs and serum were collected from healthy subjects (HS) (n = 75), including blood donors (BD) (n = 25), pregnant women at early pregnancy (EP) (n = 25), i.e., within the first trimester, and pregnant women at late pregnancy (LP) (n = 25), i.e., at the third trimester. DNA from PBMCs was treated with sodium bisulfite and PCR amplified for SERPINA1 gene promoter, followed by sequencing analyses. AAT serum levels were determined by ELISA test. SERPINA1 was found hypermethylated in 58.7% of HS. The prevalence of SERPINA1 hypermethylation was significantly higher in BD (68%) and EP (88%) than in LP (20%) (p < 0.01). The median serum AAT concentration was 1.07, 0.63, and 3.15 mg/ml in BD, EP, and LP, respectively (p < 0.05, BD and EP vs LP). This study indicates, for the first time, that SERPINA1 gene promoter is differentially methylated in PBMCs from HS. Likely, modulation of the methylation may be a novel epigenetic regulator mechanism of AAT expression in the PBMC of HS. Therefore, SERPINA1 gene promoter methylation may represent an epigenetic biomarker of PBMCs in healthy subjects
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