Search results for "FN"
showing 10 items of 862 documents
Inverse relationship between ambulatory artery stiffness index and glomerular filtration rate in essential hypertension
2007
Molecular mechanisms of primary and secondary mucosal immunity using avian infectious bronchitis virus as a model system
2007
Although mucosal immune responses are critical for protection of hosts from clinical illness and even mortality caused by mucosal pathogens, the molecular mechanism of mucosal immunity, which is independent of systemic immunity, remains elusive. To explore the mechanistic basis of mucosal protective immunity, gene transcriptional profiling in mucosal tissues was evaluated after the primary and secondary immunization of animals with an attenuated avian infectious bronchitis virus (IBV), a prototype of Coronavirus and a well-characterized mucosal pathogen. Results showed that a number of innate immune factors including toll-like receptors (TLRs), retinoic-acid-inducible gene-1 (RIG-1), type I…
New Polylactic Acid Composites Reinforced with Artichoke Fibers
2015
In this work, artichoke fibers were used for the first time to prepare poly(lactic acid) (PLA)-based biocomposites. In particular, two PLA/artichoke composites with the same fiber loading (10% w/w) were prepared by the film-stacking method: the first one (UNID) reinforced with unidirectional long artichoke fibers, the second one (RANDOM) reinforced by randomly-oriented long artichoke fibers. Both composites were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. The morphology of the fracture surfaces was analyzed through scanning electron microscopy (SEM). Moreover, a theoretical model, i.e., Hill's method, was used to fit the experimental Young's modu…
Smart switching in feedforward control of grip force during manipulation of elastic objects
2017
AbstractSwitching systems are common in artificial control systems. Here, we suggest that the brain adopts a switched feedforward control of grip forces during manipulation of objects. We measured how participants modulated grip force when interacting with soft and rigid virtual springs when stiffness varied nearly continuously between trials. We identified a sudden phase transition between two forms of feedforward control that differed in the timing of the synchronization between the anticipated load force and the applied grip force. The switch occurred several trials after a threshold stiffness level. These results suggest that in the control of grip force, the brain acts as a switching c…
Empagliflozin Induces White Adipocyte Browning and Modulates Mitochondrial Dynamics in KK Cg-Ay/J Mice and Mouse Adipocytes
2021
Background: White adipose tissue (WAT) browning is a promising target for obesity prevention and treatment. Empagliflozin has emerged as an agent with weight-loss potential in clinical and in vivo studies, but the mechanisms underlying its effect are not fully understood. Here, we investigated whether empagliflozin could induce WAT browning and mitochondrial alterations in KK Cg-Ay/J (KKAy) mice, and explored the mechanisms of its effects.Methods: Eight-week-old male KKAy mice were administered empagliflozin or saline for 8 weeks and compared with control C57BL/6J mice. Mature 3T3-L1 adipocytes were treated in the presence or absence of empagliflozin. Mitochondrial biosynthesis, dynamics, a…
On stiffness and damping of vibro-impact dynamics of backlash
2021
We consider the instantaneous stiffness and damping of the vibro-impact in a backlash pair. Opposed to the existing and mostly used models of the backlash, we address the problem of contact and separation, and the associated force propagation within a mechanical pair, from a viewpoint of the vibro-impact dynamics. We discuss the impact forces with the coefficient of restitution as a principal factor which shapes the transient backlash response.We show that a common approach to modeling the backlash by means of a dead-zone in a restoring force is unsuitable for correctly capturing the mechanical impact. We exemplary demonstrate a qualitative accord between an experimental backlash response a…
Topology Optimization Design of Internal Reinforcements in a Sailing Dinghy
2021
AbstractIn this paper, a novel approach has been followed based on FEM simulation and Topology Optimization tools to locate and model the reinforcements inside the hull of a sailing dinghy. This process assumes that the inner volume included between the hull and the deck is, at the beginning of the simulation, filled with material; then a portion of this inner volume is eroded until a final free form shape of the reinforcements is obtained. A key point of this procedure is the definition of the optimization constrains because the final shape of the reinforcements must fulfill several requirements such as weight, stiffness and stress. At the end of the optimization procedure, the final shape…
Investigation of buckling characteristics of cracked variable stiffness composite plates by an eXtended Ritz approach
2021
Abstract Variable Angle Tow (VAT) composite plates are characterized by in-plane variable stiffness properties, which opens to new concepts of stiffness tailoring and optimization to achieve higher structural performance for advanced lightweight structures where damage tolerance consideration are often mandatory. In this paper, a single-domain eXtended Ritz formulation is proposed to study the buckling behaviour of variable stiffness laminated cracked plates. The plate behaviour is described by the first order shear deformation theory whose generalized displacements, namely reference plane translations and rotations, are expressed via suitable admissible trial functions. These consist of a …
Effect of progressive collapse of central column on the push-down response of two-span beam-column substructures
2021
Abstract In this paper, a simplified model is proposed for hand calculation of the push-down curve of reinforced two-span beam-column substructures with the mid-span column subjected to a vertical load inducing progressive collapse response. The model takes into account the flexural, arch and catenary strength mechanisms and the axial stiffness of RC compressed columns. The model was validated against experimental data available in the literature. The expressions derived, in a closed form, were useful for hand calculation of push-down responses and robustness evaluation of RC framed structures. The derived explicit expressions can be applied in a step-by-step manner for tracing nonlinear be…