257 research outputs found
Nanoferroics: state of art, gradient driven couplings and advanced applications (Authors' review)
Ferroics and multiferroics are unique objects for fundamental physical
research of complex nonlinear processes and phenomena, which occur in them in
micro and nanoscale. Due to the possibility of their physical properties
control by size effects, nanostructured and nanosized ferroics are among the
most promising for advanced applications in nanoelectronics,
nanoelectromechanics, optoelectronics, nonlinear optics and information
technologies. The review discuss and analyze that the thickness of the strained
films, the size and shape of the ferroic and multiferroic nanoparticles are
unique tools for controlling their phase diagrams, long range order parameters,
magnitude of susceptibility, magnetoelectric coupling and domain structure
characteristics at fixed temperature. Significant influence of the
flexochemical effect on the phase transition temperature, polar and dielectric
properties is revealed for thin films and nanoparticles. Obtained results are
important for understanding of the nonlinear physical processes in nanoferroics
as well as for the advanced applications in nanoelectronics.Comment: 23 pages, 15 figure
The feasibility of wireless capsule endoscopy in detecting small intestinal pathology in children under the age of 8 years: a multicentre European study.
Objective: To systematically evaluate the feasibility and methodology to carry out wireless capsule endoscopy (WCE) in children <8 years to define small intestinal pathology.
Design: Prospective European multicentre study with negative prior investigation.
Patients and interventions: 83 children aged 1.5â7.9 years were recruited. Initially, all were offered âswallowingâ (Group 1) for capsule introduction. If this failed endoscopic placement (Group 2) was used and the Roth net, Advance or custom-made introducers were compared.
Outcome measures: Primary endpoint: to determine pathology; secondary endpoint: comparison of capsule introduction methods.
Results: Capsule introduction: 20 (24%) children aged 4.0â7.9 years (mean, 6.9 years; 14 male) comprising Group 1 were older (p<0.025) than 63 (76%) aged 1.5â7.9 years (mean, 5.25 years; 30 male) forming Group 2. Complications: Roth net mucosal trauma in 50%; no others occurred. The available recording apparatus was inappropriate for those <3 years. Indications: gastrointestinal bleeding: nâ=â30 (16 positive findings: four ulcerative jejunitis, four polyps, two angiodysplasia, two blue rubber blebs, two Meckelâs diverticula, one anastomotic ulcer, one reduplication); suspected Crohnâs disease: nâ=â20 (11 had Crohnâs disease); abdominal pain: nâ=â12 (six positive findings: three Crohnâs disease, two lymphonodular hyperplasia, one blue rubber bleb); protein loss: nâ=â9 (four lymphangectasia); malabsorption: nâ=â12 (seven positive findings: six enteropathy, one ascaris). No abnormalities overall: 45%.
Conclusion: WCE is feasible and safe down to the age of 1.5 years. 20 children >4 years swallowed the capsule. The Advance introducer proved superior for endoscopic placement. The pathologies encountered showed age specificity and, unlike in adolescents, obscure gastrointestinal bleeding was the commonest indication
Lifting restrictions on coherence loss when characterizing non-transparent hypersonic phononic crystals
Abstract Hypersonic phononic bandgap structures confine acoustic vibrations whose wavelength is commensurate with that of light, and have been studied using either time- or frequency-domain optical spectroscopy. Pulsed pump-probe lasers are the preferred instruments for characterizing periodic multilayer stacks from common vacuum deposition techniques, but the detection mechanism requires the injected sound wave to maintain coherence during propagation. Beyond acoustic Bragg mirrors, frequency-domain studies using a tandem FabryâPerot interferometer (TFPI) find dispersions of two- and three-dimensional phononic crystals (PnCs) even for highly disordered samples, but with the caveat that PnCs must be transparent. Here, we demonstrate a hybrid technique for overcoming the limitations that time- and frequency-domain approaches exhibit separately. Accordingly, we inject coherent phonons into a non-transparent PnC using a pulsed laser and acquire the acoustic transmission spectrum on a TFPI, where pumped appear alongside spontaneously excited (i.e. incoherent) phonons. Choosing a metallic Bragg mirror for illustration, we determine the bandgap and compare with conventional time-domain spectroscopy, finding resolution of the hybrid approach to match that of a state-of-the-art asynchronous optical sampling setup. Thus, the hybrid pumpâprobe technique retains key performance features of the established one and going forward will likely be preferred for disordered samples
Coherent magnetization precession in ferromagnetic (Ga,Mn)As induced by picosecond acoustic pulses
We show that the magnetization of a thin ferromagnetic (Ga,Mn)As layer can be
modulated by picosecond acoustic pulses. In this approach a picosecond strain
pulse injected into the structure induces a tilt of the magnetization vector M,
followed by the precession of M around its equilibrium orientation. This effect
can be understood in terms of changes in magneto-crystalline anisotropy induced
by the pulse. A model where only one anisotropy constant is affected by the
strain pulse provides a good description of the observed time-dependent
response.Comment: 13 pages, 3 figure
Bionic models for identification of biological systems
This article proposes a clinical decision support system that processes biomedical data. For this purpose a bionic model has been designed based on neural networks, genetic algorithms and immune systems. The developed system has been tested on data from pregnant women. The paper focuses on the approach to enable selection of control actions that can minimize the risk of adverse outcome. The control actions (hyperparameters of a new type) are further used as an additional input signal. Its values are defined by a hyperparameter optimization method. A software developed with Python is briefly described
The feasibility of wireless capsule endoscopy in detecting small intestinal pathology in children under the age of 8 years: a multicentre European study
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