901 resultados para Smart transducer


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The aim of the present study was to evaluate the signal transducer and activator of transcription (STAT3) expression, which is constitutively active in different types of malignant tumours, in salivary gland tumours. Fifty biopsies of salivary gland tumours (9 pleomorphic adenomas, 12 adenoid cystic carcinomas, 7 epithelial-myoepithelial carcinomas, 10 polymorphous low-grade adenocarcinomas and 12 mucoepidermoid carcinomas) and 10 normal. salivary glands were immunohistochemically labeled for STAT3 and Phospho-STAT3 (STAT3P). The labeled sections were quatitatively and quantitatively evaluated. The results showed that, in normal salivary gland, STAT3 was expressed in cytoplasm and STAT3P in nuclei of all tissue cells, except in large mucous acinar cells for which both antibodies were negative. In pleomorphic adenoma, the expression was the same as in normal glands. In malignant tumours, there were variations in the expression of these antibodies. The most important one was the presence of STAT3 in the nuclei of the malignant tumour cells, most evident in the cribriform-type of adenoid cystic carcinoma. Both toss and variation of STAT3P expression were also observed. The presence of STAT3 in the nuclei of malignant salivary gland tumours may represent an important event in oncogenesis probably contributing to tumour cell proliferation white blocking apoptosis. However, further investigation will. be necessary to support this hypothesis. (c) 2007 Pubtished by Elsevier Ltd.

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Rectangular piezoceramic transducers are widely used in ultrasonic evaluation and health monitoring techniques and structural vibration control applications. In this paper the flexural waves excited by rectangular transducers adhesively attached to isotropic plates are investigated. In view of the difficulties in developing accurate analytical models describing the transfer characteristics of the transducer due to the complex electromechanical transduction processes and transducer-structure interactions involved, a combined theoretical-experimental approach is developed. A multiple integral transform method is used to describe the propagation behaviour of the waves in the plates, while a heterodyne Doppler laser vibrometer is employed as a non-contact receiver device. This combined theoretical-experimental approach enables the efficient characterization of the electromechanical transfer properties of the piezoelectric transducer which is essential for the development of optimized non-destructive evaluation systems. The results show that the assumption of a uniform contact pressure distribution between the transducer and the plate can accurately predict the frequency spectrum and time domain response signals of the propagating waves along the main axes of the rectangular transmitter element.

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In this paper, an attempt was made to investigate a fundamental problem related to the flexural waves excited by rectangular transducers. Due to the disadvantages of the Green's function approach for solving this problem, a direct and effective method is proposed using a multiple integral transform method and contour integration technique. The explicit frequency domain solutions obtained from this newly developed method are convenient for understanding transducer behavior and theoretical optimization and experimental calibration of rectangular transducers. The time domain solutions can then be easily obtained by using the fast Fourier transform technique. (C) 2001 Elsevier Science B.V. All rights reserved.

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The acousto-ultrasonic (AU) input-output characteristics for contact-type transmitting and receiving transducers coupled to composite laminated plates are considered in this paper. Combining a multiple integral transform method, an ordinary discrete layer theory for the laminates and some simplifying assumptions for the electro-mechanical transduction behaviour of the transducers, an analytical solution is developed which can deal with all the wave processes involved in the AU measurement system, i.e, wave generation, wave propagation and wave reception. The spectral response of the normal contact pressure sensed by the receiving transducer due to an arbitrary input pulse excited by the transmitting transducer is obtained. To validate the new analytical-numerical spectral technique in the low-frequency regime, the results are compared with Mindlin plate theory solutions. Based on the analytical results, numerical calculations are carried out to investigate the influence of various external parameters such as frequency content of the input pulse, transmitter/receiver spacing and transducer aperture on the output of the measurement system. The results show that the presented analytical-numerical procedure is an effective tool for understanding the input-output characteristics of the AU technique for laminated plates. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Expansion tubes operating at total flow enthalpies of 100 MJ kg(-1) or more have characteristical test times of 30-50 mus. Under these conditions, the response time of the Pitot pressure measuring device is critical when performing flow calibration studies. The conventional technique of using a commercial pressure transducer protected by shielding has not always proven to be effective, due to the relatively large (and variable) response time caused by the shielding. A device called the stress wave bar gauge has been designed and calibrated and shown to be an effective way to measure the Pitot pressure with a response time of only 2-3 mus.

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The suitable use of an array antenna at the base station of a wireless communications system can result in improvement in the signal-to-interference ratio (SIR). In general, the SIR is a function of the direction of arrival of the desired signal and depends on the configuration of the array, the number of elements, and their spacing. In this paper, we consider a uniform linear array antenna and study the effect of varying the number of its elements and inter-element spacing on the SIR performance. (C) 2002 Wiley Periodicals, Inc.

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The suitable use of array antennas in cellular systems results in improvement in the signal-to-interference ratio (StR), This property is the basis for introducing smart or adaptive antenna systems. in general, the SIR depends on the array configuration and is a function of the direction of the desired user and interferers. Here, the SIR performance for linear and circular arrays is analysed and compared.

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A miniature pressure transducer was used to assess the interlabial contact pressures produced by a group of 19 adults (mean age 30.6 years) with dysarthria following severe traumatic brain injury (TBI) during a set of speech and nonspeech tasks. Ten parameters relating to lip strength, endurance, rate of movement and lip pressure accuracy and stability were measured from the nonspeech tasks. The results attained by the TBI group were compared against a group of 19 age- and sex-matched control subjects. Significant differences between the groups were found for maximum interlabial contact pressure, maximum rate of repetition of maximum pressure, and lip pressure accuracy at 50 and 10% levels of maximum pressure. In regards to speech, the interlabial contact pressures generated by the TBI group and control group did not differ significantly. When expressed as percentages of maximum pressure, however, the TBI group's interlabial pressures appeared to have been generated with greater physiological effort. Copyright (C) 2002 S. Karger AG, Basel.

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Primers and DNA probes designed for use in the specific detection of the paramyxean parasites Marteilia sydneyi and Marteilia refringens were tested for their potential to cross-react with closely related species in Polymerase Chain Reaction (PCR) and in situ hybridization. PCR primers and a DNA probe designed within the ITS1 rRNA of M. sydneyi were specific for M. sydneyi when compared with related species of Marteilia and Marteilioides. PCR primers designed within the 18S rRNA of M. refringens were specific in the detection of this species in PCR while a DNA probe (named Smart 2) designed on the same gene cross-reacted with M. sydneyi in tissue sections of Saccostrea glomerata as well as Marteilioides sp. infecting Striostrea mytiloides. Though not species specific, the Smart 2 probe provided a stronger signal in detection of all stages of M. sydneyi than the ITS1 probe. The ITS probe is proposed for use as a confirmatory diagnostic too] for M. sydneyi.

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An efficient representation method for arbitrarily shaped image segments is proposed. This method includes a smart way to select wavelet basis to approximate the given image segment, with improved image quality and reduced computational load.

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Cultured equine lamellar hoof explants secrete the pro-enzymes matrix metalloproteinse-2 (MMP-2, 72 kDa) and MMP-2 (92 kDa). Untreated explants remained intact tested on a calibrated force transducer, but when treated with an NIMP activator, developed in-vitro laminitis, separating at the dermal-epidermal junction. Explants treated with the bacterial protease thermolysin separated dose-dependently; this was accompanied by activation of both MMP-2 and -9. Thermolysin-mediated NIP activation did not occur in a cell-free system and was not inhibited by the addition of the MMP inhibitor and batimastat. These findings suggest that thermolysin-mediated gelatinase activation is not dependent on membrane-bound matrix metalloproteinase (MT-MMP) activation, providing further evidence that bacteria can produce potent MMP activators that probably facilitate host invasion. (C) 2002 Harcourt Publishers Ltd.

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Smart State is a Queensland Government initiative that recognises the central role of knowledge-based economic growth. In this context, the management of intellectual property (IP) within Queensland and Australian government research and development agencies has changed dramatically over recent years. Increasing expectations have been placed on utilising public sector IP to both underpin economic development and augment taxes by generating new revenues. Public sector research and development (R&D) management has come under greater scrutiny to commercialise and/or corporatise their activities. In a study of IP management issues in the Queensland Public Sector we developed a framework to facilitate a holistic audit of IP management in government agencies. In this paper we describe this framework as it pertains to one large public sector Agriculture R&D Agency, the Queensland Department of Primary Industries (QDPI). The four overlapping domains of the framework are: IP Generation; IP Rights; IP Uptake; and Corporate IP Support. The audit within QDPI, conducted in 2000 near the outset of Smart State, highlighted some well developed IP management practices within QDPI's traditional areas of focus of innovation (IP Generation) and IP ownership and licensing (IP Rights). However, further management practice developments are required to improve the domains of IP Uptake and Corporate IP Support.

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The Smart State initiative requires both improved education and training, panicularly in technical fields, plus entrepreneurship to commercialise new ideas. In this study, we propose an entrepreneurial intentions model as a guide to examine the educational choices and entrepreneurial intentions of first-year University students, focusing on the effect of role models. A survey of over 1000 first-year University students revealed that the most enterprising students were choosing to study in the disciplines of information technology and business, economics and law, or selecting dual degree programs that include business. The role models most often identified for their choice of field of study were parents, followed by teachers and peers, with females identifying more role models than males. For entrepreneurship, students' role models were parents and peers, followed by famous persons and teachers. Males andfemales identified similar numbers of role models, but malesfound starting a business more desirable and more feasible, and reponed higher entrepreneurial intention. The implications of these findings for Sman State policy are discussed.

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Skin-friction measurements are reported for high-enthalpy and high-Mach-number laminar, transitional and turbulent boundary layers. The measurements were performed in a free-piston shock tunnel with air-flow Mach number, stagnation enthalpy and Reynolds numbers in the ranges of 4.4-6.7, 3-13 MJ kg(-1) and 0.16 x 10(6)-21 x 10(6), respectively. Wall temperatures were near 300 K and this resulted in ratios of wall enthalpy to flow-stagnation enthalpy in the range of 0.1-0.02. The experiments were performed using rectangular ducts. The measurements were accomplished using a new skin-friction gauge that was developed for impulse facility testing. The gauge was an acceleration compensated piezoelectric transducer and had a lowest natural frequency near 40 kHz. Turbulent skin-friction levels were measured to within a typical uncertainty of +/-7%. The systematic uncertainty in measured skin-friction coefficient was high for the tested laminar conditions; however, to within experimental uncertainty, the skin-friction and heat-transfer measurements were in agreement with the laminar theory of van Driest (1952). For predicting turbulent skin-friction coefficient, it was established that, for the range of Mach numbers and Reynolds numbers of the experiments, with cold walls and boundary layers approaching the turbulent equilibrium state, the Spalding & Chi (1964) method was the most suitable of the theories tested. It was also established that if the heat transfer rate to the wall is to be predicted, then the Spalding & Chi (1964) method should be used in conjunction with a Reynolds analogy factor near unity. If more accurate results are required, then an experimentally observed relationship between the Reynolds analogy factor and the skin-friction coefficient may be applied.

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The ability of viral or mutated cellular oncogenes to initiate neoplastic events and their poor immunogenicity have considerably undermined their potential use as immunotherapeutic tools for the treatment of human cancers. Using an EpsteinBarr virus-encoded oncogene, latent membrane protein 1 (LMP1), as a model, we report a novel strategy that both deactivates cellular signaling pathways associated with the oncogenic phenotype and reverses poor immunogenicity. We show that cotranslational ubiquitination combined with Wend rule targeting of LMP1 enhanced the intracellular degradation of LMP1 and total blockade of LMP1-mediated nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription (STAT) activation in human cells. In addition, although murine cells expressing LMP1 were uniformly tumorigenic, this oncogenicity was completely abrogated by covalent linkage of LMP1 with ubiquitin, while an enhanced CD8(+) T cell response to a model epitope fused to the C-terminus of LMP1 was observed following immunization with ubiquitinated LMP1. These observations suggest that proteasomal targeting of tumor-associated oncogenes could be exploited therapeutically by either gene therapy or vaccination.