8,305 research outputs found
Testing a quintessence model with CMBR peaks locations
We show that a model of quintessence with exponential potential,
which allows to obtain general exact solutions, can generate location of
CMBR peaks which are fully compatible with present observational data
Cardiac oxidative stress and inflammatory cytokines response after myocardial infarction
Oxidative stress in heart failure or during ischemia/reperfusion occurs as a result of the excessive generation or accumulation of free radicals or their oxidation products. Free radicals formed during oxidative stress can initiate lipid peroxidation, oxidize proteins to inactive states and cause DNA strand breaks. Oxidative stress is a condition in which oxidant metabolites exert toxic effects because of their increased production or an altered cellular mechanism of protection. In the early phase of acute heart ischemia cytokines have the feature to be functional pleiotropy and redundancy, moreover, several cytokines exert similar and overlapping actions on the same cell type and one cytokine shows a wide range of biological effects on various cell types. Activation of cytokine cascades in the infarcted myocardium was established in numerous studies. In experimental models of myocardial infarction, induction and release of the pro-inflammatory cytokines like TNF-&alpha (Tumor Necrosis Factor &alpha), IL-1&beta (Interleukin- 1&beta) and IL-6 (Interleukin-6) and chemokines are steadily described. The current review examines the role of oxidative stress and pro-inflammatory cytokines response following acute myocardial infarction and explores the inflammatory mechanisms of cardiac injur
A true-time-delay networks design technique
This paper proposes a technique to design wide band switched-line (SL) true-time-delay (TTD) networks, commonly used for
phased array antenna (PAA) applications. This study investigates the constant-delay behavior of switched-line phase shifters
based on single-pole double-throw (SPDT) switches. Circuit sizing starts by considering the effective S-parameters of the
switches, to use their non-idealities as an integral part of the phase shift linearly dependent to the frequency and by considering,
from the beginning, the possible spatial positioning of elements that allows the circuit feasibility as a design target. The
aim of this study is to provide a technique suitable for the design of well-matched TTD networks with a flat delay in wide
bandwidth. In this paper, we propose new design formulas for which we show a single-frequency implementation. A computational
strategy is used to obtain numerical solutions of the derived equations with this study. Finally, a monolithic X-band
TTD circuit example is shown
Estimating the conditions for polariton condensation in organic thin-film microcavities
We examine the possibility of observing Bose condensation of a confined
two-dimensional polariton gas in an organic quantum well. We deduce a suitable
parameterization of a model Hamiltonian based upon the cavity geometry, the
biexciton binding energy, and similar spectroscopic and structural data. By
converting the sum-over-states to a semiclassical integration over
-dimensional phase space, we show that while an ideal 2-D Bose gas will not
undergo condensation, an interacting gas with the Bogoliubov dispersion
close to will undergo Bose condensation at a given
critical density and temperature. We show that is sensitive
to both the cavity geometry and to the biexciton binding energy. In particular,
for strongly bound biexcitons, the non-linear interaction term appearing in the
Gross-Pitaevskii equation becomes negative and the resulting ground state will
be a localized soliton state rather than a delocalized Bose condensate.Comment: 2 figure
WDR79/TCAB1 plays a conserved role in the control of locomotion and ameliorates phenotypic defects in SMA models
SMN (Survival Motor Neuron) deficiency is the predominant cause of spinal muscular atrophy (SMA), a severe neurodegenerative disorder that can lead to progressive paralysis and death. Although SMN is required in every cell for proper RNA metabolism, the reason why its loss is especially critical in the motor system is still unclear. SMA genetic models have been employed to identify several modifiers that can ameliorate the deficits induced by SMN depletion. Here we focus on WDR79/TCAB1, a protein important for the biogenesis of several RNA species that has been shown to physically interact with SMN in human cells. We show that WDR79 depletion results in locomotion defects in both Drosophila and Caenorhabditis elegans similar to those elicited by SMN depletion. Consistent with this observation, we find that SMN overexpression rescues the WDR79 loss-of-function phenotype in flies. Most importantly, we also found that WDR79 overexpression ameliorates the locomotion defects induced by SMN depletion in both flies and worms. Our results collectively suggest that WDR79 and SMN play evolutionarily conserved cooperative functions in the nervous system and suggest that WDR79/TCAB1 may have the potential to modify SMA pathogenesis
"All on short" prosthetic-implant supported rehabilitations
Objectives. Short implants are increasing their popularity among clinicians who want to fulfill the constant demanding of fixed prosthetic solutions in edentulous jaws. The aim of this report was to propose a new possibility to project and realize an occlusal guided implant cross-arch prosthesis supported by ultra-short implants, describing it presented an edentulous mandible case report. Methods. A 61-year-old, Caucasian, female patient who attended the dental clinic of the University of L’Aquila presented with edentulous posterior inferior jaw and periodontitis and periimplantitis processes in the anterior mandible. The remaining tooth and the affected implant were removed. Six 4-mm-long implants were placed to support a cross-arch metal-resin prosthesis. Results. At 1-year follow-up clinical and radiological assessment showed a good osseointegration of the fixtures and the patient was satisfied with the prosthesis solution. Conclusion. The method, even if it requires further validation, seems to be a valid aid in solving lower edentulous clinical cases, and appears less complex and with more indications of other proposals presented in the current clinical literature. Our case report differs from the current technique All-on-Four, which uses four implants in the mandible to support overdenture prosthesis, assuring a very promising clinical resul
Spatially embedded random networks
Many real-world networks analyzed in modern network theory have a natural spatial element; e.g., the Internet, social networks, neural networks, etc. Yet, aside from a comparatively small number of somewhat specialized and domain-specific studies, the spatial element is mostly ignored and, in particular, its relation to network structure disregarded. In this paper we introduce a model framework to analyze the mediation of network structure by spatial embedding; specifically, we model connectivity as dependent on the distance between network nodes. Our spatially embedded random networks construction is not primarily intended as an accurate model of any specific class of real-world networks, but rather to gain intuition for the effects of spatial embedding on network structure; nevertheless we are able to demonstrate, in a quite general setting, some constraints of spatial embedding on connectivity such as the effects of spatial symmetry, conditions for scale free degree distributions and the existence of small-world spatial networks. We also derive some standard structural statistics for spatially embedded networks and illustrate the application of our model framework with concrete examples
Defective Behaviour of an 8T SRAM Cell with Open Defects
The defective behaviour of an 8T SRAM cell with open defects is analyzed. Full and resistive open defects have been considered in the electrical characterization of the defective cell. Due to the similarity between the classical 6T SRAM cell and the 8T cell, only defects affecting the read port transistors have been considered. In the work, it is shown how an open in a defective cell may influence the correct operation of a victim cell sharing the same read circuitry. Also, it is shown that the sequence of bits written on the defective cell prior to a read action can mask the presence of the defect. Different orders of critical resistance have been found depending on the location of the open defect. A 45nm technology has been used for the illustrative example presented in the wor
Radon mitigation during the installation of the CUORE decay detector
CUORE - the Cryogenic Underground Observatory for Rare Events - is an
experiment searching for the neutrinoless double-beta () decay
of Te with an array of 988 TeO crystals operated as bolometers at
10 mK in a large dilution refrigerator. With this detector, we aim for a
Te decay half-life sensitivity of y
with 5 y of live time, and a background index of
counts/keV/kg/y. Making an effort to maintain radiopurity by minimizing the
bolometers' exposure to radon gas during their installation in the cryostat, we
perform all operations inside a dedicated cleanroom environment with a
controlled radon-reduced atmosphere. In this paper, we discuss the design and
performance of the CUORE Radon Abatement System and cleanroom, as well as a
system to monitor the radon level in real time.Comment: 10 pages, 6 figures, 1 tabl
Biochemomechanics of intraluminal thrombus in abdominal aortic aneurysms
Most computational models of abdominal aortic aneurysms address either the hemodynamics within the lesion or the mechanics of the wall. More recently, however, some models have appropriately begun to account for the evolving mechanics of the wall in response to the changing hemodynamic loads. Collectively, this large body of work has provided tremendous insight into this life-threatening condition and has provided important guidance for current research. Nevertheless, there has yet to be a comprehensive model that addresses the mechanobiology, biochemistry, and biomechanics of thrombus-laden abdominal aortic aneurysms. That is, there is a pressing need to include effects of the hemodynamics on both the development of the nearly ubiquitous intraluminal thrombus and the evolving mechanics of the wall, which depends in part on biochemical effects of the adjacent thrombus. Indeed, there is increasing evidence that intraluminal thrombus in abdominal aortic aneurysms is biologically active and should not be treated as homogeneous inert material. In this review paper, we bring together diverse findings from the literature to encourage next generation models that account for the biochemomechanics of growth and remodeling in patient-specific, thrombus-laden abdominal aortic aneurysms
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