8,616 research outputs found
Free vibration of a three-layered sandwich beam using the dynamic stiffness method and experiment
In this paper, an accurate dynamic stiffness model for a three-layered sandwich
beam of unequal thicknesses is developed and subsequently used to investigate
its free vibration characteristics. Each layer of the beam is idealised by the
Timoshenko beam theory and the combined system is reduced to a tenth-order
system using symbolic computation. An exact dynamic stiffness matrix is then
developed by relating amplitudes of harmonically varying loads to those of the
responses. The resulting dynamic stiffness matrix is used with particular
reference to the Wittrick-Williams algorithm to carry out the free vibration
analysis of a few illustrative examples. The accuracy of the theory is confirmed
both by published literature and by experiment. The paper closes with some
concluding remarks. (c) 2007 Elsevier Ltd. All rights reserved
Single Chip Solution with1-Wire Communication Protocol to Interface Digital Transducers to Sensor Networks
A virtual laboratory application setup is used to control and monitorremotely the operation of several sensor nodes placed at different geographicallocations. In this paper, we present the design of a generalized, low-cost and reconfigurablesmart sensor node using a Zigbee with a Field-Programmable Gate Array(FPGA) that embeds all processing and communication functionalities based on theIEEE 1451 family of standards with communication taking place through a 1-wireprotocol. The architecture of the sensor node is based on the single chip concept thatincludes communication, processing and transducer control functionalities. Theproposed architecture reduces the physical size, power and increases speedup ofprocessing due to inter-module communication. Results indicate the accuracy of theproposed system is tested with a temperature sensor which has 1-wire protocol
Optimizing CIGB-300 intralesional delivery in locally advanced cervical cancer
Background:We conducted a phase 1 trial in patients with locally advanced cervical cancer by injecting 0.5 ml of the CK2-antagonist CIGB-300 in two different sites on tumours to assess tumour uptake, safety, pharmacodynamic activity and identify the recommended dose.Methods:Fourteen patients were treated with intralesional injections containing 35 or 70 mg of CIGB-300 in three alternate cycles of three consecutive days each before standard chemoradiotherapy. Tumour uptake was determined using 99 Tc-radiolabelled peptide. In situ B23/nucleophosmin was determined by immunohistochemistry.Results:Maximum tumour uptake for CIGB-300 70-mg dose was significantly higher than the one observed for 35 mg: 16.1±8.9 vs 31.3±12.9 mg (P=0.01). Both, AUC 24h and biological half-life were also significantly higher using 70 mg of CIGB-300 (P<0.001). Unincorporated CIGB-300 diffused rapidly to blood and was mainly distributed towards kidneys, and marginally in liver, lungs, heart and spleen. There was no DLT and moderate allergic-like reactions were the most common systemic side effect with strong correlation between unincorporated CIGB-300 and histamine levels in blood. CIGB-300, 70 mg, downregulated B23/nucleophosmin (P=0.03) in tumour specimens.Conclusion:Intralesional injections of 70 mg CIGB-300 in two sites (0.5 ml per injection) and this treatment plan are recommended to be evaluated in phase 2 studies.Fil: Sarduy, M. R.. Medical-surgical Research Center; CubaFil: GarcĂa, I.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: Coca, M. A.. Clinical Investigation Center; CubaFil: Perera, A.. Clinical Investigation Center; CubaFil: Torres, L. A.. Clinical Investigation Center; CubaFil: Valenzuela, C. M.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: BaladrĂłn, I.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: Solares, M.. Hospital Materno RamĂłn González Coro; CubaFil: Reyes, V.. Center For Genetic Engineering And Biotechnology Havana; CubaFil: Hernández, I.. Isotope Center; CubaFil: Perera, Y.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: MartĂnez, Y. M.. Medical-surgical Research Center; CubaFil: Molina, L.. Medical-surgical Research Center; CubaFil: González, Y. M.. Medical-surgical Research Center; CubaFil: AncĂzar, J. A.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: Prats, A.. Clinical Investigation Center; CubaFil: González, L.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: CasacĂł, C. A.. Clinical Investigation Center; CubaFil: Acevedo, B. E.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: LĂłpez Saura, P. A.. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; CubaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; ArgentinaFil: GĂłmez, R.. Elea Laboratories; ArgentinaFil: Perea RodrĂguez, S. E.. Center For Genetic Engineering And Biotechnology Havana; Cuba. Centro de IngenierĂa GenĂ©tica y BiotecnologĂa; Cub
Diagnostic accuracy studies: how to report and analyse inconclusive test results.
Failure to report inconclusive test results can lead to misleading conclusions regarding the accuracy and clinical usefulness of a diagnostic tool. We show that these results are often overlooked in research on test accuracy and provide guidance on suitable approaches to reporting and analysing these problematic results
The Double Pulsar Eclipses I: Phenomenology and Multi-frequency Analysis
The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise
around conjunction when the radio waves emitted by pulsar A are absorbed as
they propagate through the magnetosphere of its companion pulsar B. These
eclipses offer a unique opportunity to probe directly the magnetospheric
structure and the plasma properties of pulsar B. We have performed a
comprehensive analysis of the eclipse phenomenology using multi-frequency radio
observations obtained with the Green Bank Telescope. We have characterized the
periodic flux modulations previously discovered at 820 MHz by McLaughlin et
al., and investigated the radio frequency dependence of the duration and depth
of the eclipses. Based on their weak radio frequency evolution, we conclude
that the plasma in pulsar B's magnetosphere requires a large multiplicity
factor (~ 10^5). We also found that, as expected, flux modulations are present
at all radio frequencies in which eclipses can be detected. Their complex
behavior is consistent with the confinement of the absorbing plasma in the
dipolar magnetic field of pulsar B as suggested by Lyutikov & Thompson and such
a geometric connection explains that the observed periodicity is harmonically
related to pulsar B's spin frequency. We observe that the eclipses require a
sharp transition region beyond which the plasma density drops off abruptly.
Such a region defines a plasmasphere which would be well inside the
magnetospheric boundary of an undisturbed pulsar. It is also two times smaller
than the expected standoff radius calculated using the balance of the wind
pressure from pulsar A and the nominally estimated magnetic pressure of pulsar
B.Comment: 9 pages, 7 figures, 3 tables, ApJ in pres
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