1,721,629 research outputs found
Recent achievements on underwater optical wireless communication [Invited]
Full text linkThe growing number of underwater activities is giving momentum to the development of new technologies, such as buoys, remotely operated vehicles, and autonomous underwater vehicles. The data collected by these vehicles need to be transmitted to a high-speed central unit. Clearly, wired solutions are not suitable, since they strongly impact the mobility. In this scenario, a promising solution is offered by underwater optical wireless communication (UOWC) technology, which can achieve both high-speed and wireless operation. Here, we provide a comprehensive survey on the challenges, the experimental realizations, and the state of the art in UOWC researches
New therapies for muscular dystrophy: cautious optimism.
Full text linkThe quest for a therapy for muscular dystrophy has been the driving force behind the past 40 years of advances in this field. Numerous results, such as the identification of satellite cells and gene mutations that are responsible for most forms of dystrophies, advances in gene transfer and modification technology and, more recently, stem cells, have fueled hopes. However, administering corticosteroids still remains the only effective treatment available. Several recent advances have uncovered a diversity of possible therapeutic approaches, from pharmacological treatments to gene therapy (exon-skipping and adeno-associated viruses) and cell therapy with different types of newly identified stem cells. Importantly, a combination of these strategies might greatly enhance the possibility of successful therapy
Myogenic stem cells for the therapy of primary myopathies: wishful thinking or therapeutic perspective?
No full textPrimary myopathies are characterized by a progressive wasting of skeletal muscle that leads to deterioration of movements and, in the most severe cases, such as in Duchenne’s muscular dystrophy (DMD), to complete paralysis and death. Most myopathies in which the molecular defect has been identified are due to mutations affecting proteins that form a supramolecular link between the cytoskeleton and the extracellular matrix, such as dystrophin, the mutated protein in DMD. In the absence of one of these proteins, mechanical stress associated with contraction progressively leads to degeneration of the muscle fiber, although the underlying mechanisms are still poorly understood. In the first phase of the disease, new muscle fibers are formed by fusion of resident myoblasts, called satellite cells, which also bear the molecular defect of the fibers that they replace, and hence undergo the same fate. Once the proliferation potential of satellite cells is exhausted, there is no further regeneration and the skeletal muscle is replaced by connective tissu
Finite size phase transitions in QCD with adjoint fermions
No full textWe perform a lattice investigation of QCD with three colors and 2 flavors of Dirac (staggered) fermions in the adjoint representation, defined on a 4d space with one spatial dimension compactified, and study the phase structure of the theory as a function of the size Lc of the compactified dimension. We show that four different phases take place, corresponding to different realizations of center symmetry: two center symmetric phases, for large or small values of Lc, separated by two phases in which center symmetry is broken
in two different ways; the dependence of these results on the quark mass is discussed. We study also chiral properties and how they are affected by the different realizations of center symmetry; chiral symmetry, in particular, stays spontaneously broken at the phase
transitions and may be restored at much lower values of the compactification radius. Our results could be relevant to a recently proposed conjecture [7] of volume indepedence of QCD with adjoint fermions in the large Nc limit
A 3D indoor positioning system based on common visible LEDs
Full text linkWe propose a realistic 3D positioning system for indoor navigation that exploits visible Light EmittingDiodes (LEDs), placed on the ceiling. A unique frequency tone is assigned to each lamp and modulatesits intensity in periodic time slots. The Time Difference of Arrival (TDOA) is measured without theneed of a synchronization system between the sources and the receiver, then it is used to accuratelyestimate the receiver position. We first describe the theoretical approach, then propose the modeland characterize the possible sources of noise. Finally, we demonstrate the proof-of-concept of theproposed system by simulation of lightwave propagation. Namely, we assess its performance by usingMontecarlo simulations in a common room and estimate the impact of the different implementationparameters on the accuracy of the proposed solution. We find that, in realistic conditions, thetechnique allows for centimeter precision. Pushing the device requirements, the precision can befurther increased to a sub-centimeter accuracy
Pericytes in development and pathology of skeletal muscle
No full textIncreasing attention is currently devoted to the multiple roles that pericytes (also defined as mural, Rouget, or perivascular cells) may play during angiogenesis, vascular homeostasis, and pathology. Many recent excellent reviews thoroughly address these topics (see below); hence, we will not discuss them in detail here. However, not much is known about origin, heterogeneity, gene expression, and developmental potential of pericytes during fetal and postnatal development. This is likely because of the paucity of markers expressed by pericytes and the absence of truly unique ones. Thus, in vivo identification and ex perspective isolation are challenging and explain the relative little data available in comparison with neighbor but far more characterized cells such as the endothelium. Despite this preliminary knowledge, we will propose that contribution to growing mesoderm tissues may be an important role for pericytes. Thus, their ability to contribute to tissue regeneration may be a consequence of their role in tissue growth. However, in a severely damaged or diseased tissue, acute or chronic inflammation likely results in the production of signaling molecules that are different from those present in developing tissues, thus explaining why pericytes are easily diverted from a regenerative to a fibrotic fate. © 2013 American Heart Association, Inc
Subthalamic nucleus stimulation and gait in Parkinson’s Disease: A not always fruitful relationship
No full textDeep brain stimulation (DBS) of the subthalamic nucleus (STN) provides efficient treatment for the
alleviation of motor signs in patients with advanced Parkinson’s disease (PD), but its specific effects on
gait is sometimes less successful as it may even lead to an aggravation of freezing of gait. To better
understand when axial symptoms can be expected to improve and when they may worsen or be resistant
to STN-DBS, we propose here a narrative review that considers the recent literature evidences based on
instrumental gait analysis data. Our aim is to report about the efficacy of STN-DBS on PD gait, analyzing
the clinical and procedural factors involved, and discussing the strategies for optimizing such
effectiveness in patients with advanced PD
Wnt signaling and the activation of myogenesis in mammals
No full textIn the amniote embryos, specification of skeletal myoblasts occurs in the paraxial mesoderm in response to a number of signaling molecules produced by neighboring tissues such as neural tube, notochord and dorsal ectoderm. Candidate molecules for this complex signaling activity include Sonic hedgehog, Wnts and Noggin as positive activators and BMP4 as a possible inhibitor, Recently, the receptors and the post-receptor pathways for Sonic hedgehog and Wnts have been characterized, and this has opened up the possibility of linking these signaling events to the activation of myogenic regulatory factor genes such as Myf5 and MyoD and functionally related genes such as Pax3, Here we focus on the role of Wnts, their putative receptors Frizzled and the soluble antagonist Frzb1 in regulating mammalian myogenesis. Although it is becoming evident that the signaling downstream of Frizzled receptors is much more complex than anticipated, it is conceivable that it may lead to transcriptional activation of Myf5 and MyoD and to initiation of myogenesis;However, the fact that both Wnts and Sonic hedgehog have a strong effect on cell proliferation and survival suggests that they may contribute to the overall process of myogenesis by a combination of these different biological activities
Lactosaminoglycans synthesized by mouse male germ cels are fucosylated by an epididymal fucosyltransferase
No full textFinite size phase transitions in QCD with adjoint fermions
No full textWe perform a lattice investigation of QCD with three colors and 2 flavors of
Dirac (staggered) fermions in the adjoint representation, defined on a 4d space
with one spatial dimension compactified, and study the phase structure of the
theory as a function of the size Lc of the compactified dimension. We show that
four different phases take place, corresponding to different realizations of
center symmetry: two center symmetric phases, for large or small values of Lc,
separated by two phases in which center symmetry is broken in two different
ways; the dependence of these results on the quark mass is discussed. We study
also chiral properties and how they are affected by the different realizations
of center symmetry; chiral symmetry, in particular, stays spontaneously broken
at the phase transitions and may be restored at much lower values of the
compactification radius. Our results could be relevant to a recently proposed
conjecture of volume indepedence of QCD with adjoint fermions in the large Nc
limit
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