101,918 research outputs found
Estimate of the axial force in slender beams with unknown boundary conditions using one flexural mode shape
No full textThis paper presents an experimental procedure for the axial load identification of slender prismatic beams with unknown boundary conditions by making use of one vibration frequency and of five amplitudes of the corresponding mode shape. In fact, this method does not require the knowledge of the effective length of the beam under examination, but only the flexural rigidity and mass per unit length. The proposed algorithm was verified by means of many numerical and experimental tests on tie-rods having different boundary conditions. Excellent estimates of the axial forces were obtained. Finally, the influence of the location of the instrumented sections on the estimation of the axial load was analyzed using a simply supported beam model
The influence of the concrete cyclic laws on the dynamic response of slender RC walls
No full textThe cyclic laws for dynamic analyses of reinforced concrete (RC) structures usually neglect the concrete traction strength and the re-loading branch from traction to compression. These assumptions may lead to unreal results in cyclic or dynamics analyses. For example, flag-shaped moment-curvature diagrams of slender RC walls are presented. For this reason, the behaviour of concrete in cyclic tension, determined by Reinhardt et al. (1986,1989) and modified by Ferracuti and Savoia (2005), is added to an existing cyclic stress-strain law. Making use of the finite element (FE) software OpenSees, the resulting concrete law is firstly validated by simulating experimental tests on RC cantilever beams cyclically loaded. Then, slender RC walls in multi-storey buildings are considered and dynamic analyses are done. Moment-curvature curves at base sections are obtained, together with force and displacement envelopes. The results obtained with the implemented law are compared against the ones obtained with a common law. Results show that concrete reloading behaviour from tension to compression affects significantly the walls designed for a larger response in the inelastic field
Studio sull’applicabilità della tecnica degli ultrasuoni nella diagnostica delle travi lignee
No full textLo scopo di questo lavoro è quello di verificare l’applicabilità delle tecniche non distruttive di tipo ultrasonico nella stima dei parametri elastici del legno e nella individuazione di eventuali zone di degrado nelle travi lignee in oper
Prefazione
No full textPresenta un lavoro di ricerca avente per oggetto ipotesi per la costruzione di un sistema tecnologico con i semilavorati in composito pultruso prresenti sul mercato delle costruzioni
THE MITOCHONDRIAL HEAT SHOCK PROTEIN TRAP1 IS INVOLVED IN PROTEINS QUALITY CONTROL IN THE ENDOPLASMIC RETICULUM?
No full textAdaptation to Oxidative Stress, Chemoresistance, and Cell Survival
No full textThe discovery of some additional properties and functions of reactive oxygen species (ROS), beyond their toxic
effects, provides a novel scenario for the molecular basis and cell regulation of several pathophysiologic processes.
ROS are generated by redox-sensitive, prosurvival signaling pathways and function as second messengers
in the transduction of several extracellular signals. A complex intracellular redox buffering network has
developed to adapt and protect cells against the dangerous effects of oxidative stress. However, pathways
involved in ROS-adaptive response may also play a critical role in protecting cells against cytotoxic effects of
anticancer agents, thus supporting the hypothesis of a correlation between adaptation=resistance to oxidative
stress and resistance to anticancer drugs. This review summarizes the main systems involved in the adaptive
responses: an overview on the pathophysiologic relevance of mitochondria on redox-sensitive transcription
factors and genes and main antioxidant networks in tumor cells is provided. One of the major aims is to
highlight the adaptive mechanisms and their interplay in the intricate connection between oncogenic signaling,
oxidative stress, and chemoresistance. Clarification of these mechanisms has tremendous application potential,
in terms of developing novel molecular-targeted anticancer therapies and innovative strategies for rational
combination of these agents with chemotherapeutic or tumor-specific biologic drugs
Adaptation to oxidative stress, chemoresistance and cell survival
No full textThe discovery of some additional properties and functions of reactive oxygen species (ROS), beyond their toxic effects, provides a novel scenario for the molecular basis and cell regulation of several pathophysiologic processes. ROS are generated by redox-sensitive, prosurvival signaling pathways and function as second messengers in the transduction of several extracellular signals. A complex intracellular redox buffering network has developed to adapt and protect cells against the dangerous effects of oxidative stress. However, pathways involved in ROS-adaptive response may also play a critical role in protecting cells against cytotoxic effects of
anticancer agents, thus supporting the hypothesis of a correlation between adaptation=resistance to oxidative
stress and resistance to anticancer drugs. This review summarizes the main systems involved in the adaptive
responses: an overview on the pathophysiologic relevance of mitochondria on redox-sensitive transcription factors and genes and main antioxidant networks in tumor cells is provided. One of the major aims is to highlight the adaptive mechanisms and their interplay in the intricate connection between oncogenic signaling, oxidative stress, and chemoresistance. Clarification of these mechanisms has tremendous application potential, in terms of developing novel molecular-targeted anticancer therapies and innovative strategies for rational combination of these agents with chemotherapeutic or tumor-specific biologic drugs
Reliability of the short-term moduli of PFRP profiles
No full textThe estimate of shear and flexural properties of pultruded structural shapes is traditionally evaluated
by means of three or four point bending tests, making use of Timoshenko’s beam model. The
identification of these parameters may be highly sensitive to the test configuration and to the
measurement errors. To analyze this drawback a new test configuration was compared with the
traditional loading tests through an extensive experimental program concerning wide-flange
commercial profiles. A parametric study was conducted by varying the span length, and, in the case of
the four-point bending tests, the relative position of the applied loads. The influence of the load and
deflection measurement errors was analyzed and proper uncertainty bands were provided for the
computed rigidities
Dynamic analysis of multiply-connected perforated shear cores
No full textBy means of an energy equivalence condition, the perforated shear core is reduced to a non-homogeneous (possibly multi-cell) thin-walled beam. A continuum model for the dynamic analysis of such thin-walled beam is presented, allowing for shear deformations due to non uniform bending and torsion. Axial unknown functions are discretized by means of a hierarchical F.E. formulation, resulting in a straightforward method of calculation. Excellent agreement is found with experimental results
Nerve Growth Factor, Acting Through TrkA, Down-Regulates the Inflammatory Response in Human Monocytes After Toll-Like Receptor Stimulation.
No full text- …
