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61.
Moulthrop AA Muha MS Hadimioglu B Silva CP Kozlowski GC 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1992,39(2):204-211
The operation of an acoustic microscope having a resolution of 15 mm has been demonstrated. It uses as a coupling medium superfluid (4 )He colder than 0.9 K and pressurized to greater than 20 bar. The microscope has been used to image objects that show little or no contrast on a scanning electron microscope. In addition, the acoustic microscope has been used to study the properties of sound propagation in the coupling fluid. At low acoustic intensities, the coupling fluid has very low acoustic attenuation at the microscope's operating frequency (15.3 GHz), but near the focal point the acoustic intensity can be high enough that the helium behaves with extreme nonlinearity. In fact, this medium is capable of entering new regimes of nonlinear interaction. Plots of the received signal versus input power display a nearly complete source depletion at certain input power levels and a reconversion to the source frequency at higher power levels. Arguments that the process underlying this nonlinear behavior is harmonic generation are presented. 相似文献
62.
Sofia Cotton Dylan Ferreira Janine Soares Andreia Peixoto Marta Relvas-Santos Rita Azevedo Paulina Piairo Lorena Diguez Carlos Palmeira Luís Lima Andr M. N. Silva Lúcio Lara Santos Jos Alexandre Ferreira 《International journal of molecular sciences》2021,22(4)
Esophageal cancer (EC) is a life-threatening disease, demanding the discovery of new biomarkers and molecular targets for precision oncology. Aberrantly glycosylated proteins hold tremendous potential towards this objective. In the current study, a series of esophageal squamous cell carcinomas (ESCC) and EC-derived circulating tumor cells (CTCs) were screened by immunoassays for the sialyl-Tn (STn) antigen, a glycan rarely expressed in healthy tissues and widely observed in aggressive gastrointestinal cancers. An ESCC cell model was glycoengineered to express STn and characterized in relation to cell proliferation and invasion in vitro. STn was found to be widely present in ESCC (70% of tumors) and in CTCs in 20% of patients, being associated with general recurrence and reduced survival. Furthermore, STn expression in ESCC cells increased invasion in vitro, while reducing cancer cells proliferation. In parallel, an ESCC mass spectrometry-based proteomics dataset, obtained from the PRIDE database, was comprehensively interrogated for abnormally glycosylated proteins. Data integration with the Target Score, an algorithm developed in-house, pinpointed the glucose transporter type 1 (GLUT1) as a biomarker of poor prognosis. GLUT1-STn glycoproteoforms were latter identified in tumor tissues in patients facing worst prognosis. Furthermore, healthy human tissues analysis suggested that STn glycosylation provided cancer specificity to GLUT1. In conclusion, STn is a biomarker of worst prognosis in EC and GLUT1-STn glycoforms may be used to increase its specificity on the stratification and targeting of aggressive ESCC forms. 相似文献
63.
64.
1 INTRODUCTIONTi 6Al 4VisoneofthemostimportantTial loys[1,2 ] .Butthisalloyhasbadformabilityforitshighelasticresilience .Therefore ,hotsizingisimpor tant[36 ] .Asthebaseofhotsizing ,thestudyofstressrelaxationhasimportanttheoreticalvalueandpracticalsignificance .Ontheotherhand ,Ti 6Al 4Visusedasfastenermaterialssometimes .Whenthefastenersworkatthetemperaturehigherthanroomtemperature ,stressrelaxationmayresultsinacci dents .Sohowtopreventthestressrelaxationisveryimportant[7] .Uptonow ,… 相似文献
65.
A. H. Bott J. C. Suita A. G. da Silva P. E. V. de Miranda 《Surface & coatings technology》1995,70(2-3):257-260
1H(,p) 4He scattering cross-sections were determined for the 6.5–13 MeV (incident energy) range, thereby extending the energy range for such data beyond that available in the literature. These values are essential for the further development of hydrogen concentration profiling by the transmission elastic recoil detection technique, of particular interest in the design of surface-engineered hydrogen contamination barriers for steels. 相似文献
66.
Joo Batista A. Silva Regina C. M. de Paula Judith P. A. Feitosa Eduardo Diogo Gurgel‐Filho Claudio Maniglia‐Ferreira Francisco Jose de Souza Filho 《应用聚合物科学杂志》2006,100(5):4082-4088
Gutta‐percha cone is the most widely used material for root canal filling. The in vivo aging of this cone focus on the degradation of its main organic component, trans‐1,4‐polyisoprene, was studied. Aged cones (25 samples) from 2 to 30 years of root canal filling were extracted from different patients in the occasion of retreatment by mechanical way. The information about the aging time was given by the patients. Gel‐permeation chromatography (GPC) and infrared spectroscopy (FTIR) were the analytical techniques used. Polyisoprene degrades with time of aging, but in a slow process. Decrease in polymer molar mass from 5.7 × 105 to 1.7 × 105 g/mol was observed in polyisoprene from cone after 30 years of root canal filling and inside a noninfected tooth. In tooth with caries and periodontal infection, the decrease in molar mass is higher (4.6 × 104 g/mol in cone with 10 years of aging). The production of carbonyl and hydroxyl groups in the aged material indicates that the process is oxidative, even in closed teeth. In these cases, the oxygen could be provided from tissue fluid. The degradation mechanism is complex and depends on many factors, besides time of root canal filling. The dental problem caused by the aging could be the production and migration of cytotoxic substances to periodontal ligament and the reduction on the canal sealing property due to the polymer weight loss. Both of them could contribute to the root canal treatment failure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:4082–4088, 2006 相似文献
67.
Summary The catalytic performance (activity and polymer properties) of metallocenes with different symmetries in combination with methylaluminoxane (MAO) in the polymerization of propylene has been investigated at different temperatures, under standardized reaction conditions. The zirconocene rac-ethylene (5-1-indenyl) zirconium (IV) dichloride, with C2 symmetry, produces isotatic polypropylene and isopropylidene(5-cyclopentadienyl (5-9-fluorenyl) zirconium (IV) dichloride, with C
S
symmetry, syndiotactic polypropylene. The degree of the tacticity of these polymers increases with decreasing polymerization temperature. Only atactic polypropylene was formed with the unbridged zirconocenes bis(5-cyclopentadienyl) zirconium (IV) dichloride and bis(5-indenyl zirconium (IV) dichloride at any temperature investigated (10–60°C). 相似文献
68.
Fiber Coating Concepts for Brittle-Matrix Composites 总被引:4,自引:0,他引:4
Janet B. Davis Jan P. A. Löfvander Anthony G. Evans Ewald Bischoff Mario L. Emiliani 《Journal of the American Ceramic Society》1993,76(5):1249-1257
The current interest in tough, high-temperature materials has motivated fiber coating development for brittle-matrix composites with brittle reinforcements. Such coatings are needed for controlled interface debonding and frictional sliding. The system investigated in this study was sapphire fiber-reinforced alumina. This system is thermochemically stable for severe use conditions, exhibits little thermal expansion mismatch, and utilizes the excellent strength and creep resistance of sapphire reinforcements. Porous oxide and refractory metal coatings which satisfy requirements for toughness improvement in these composites were identified by employing a variety of newly developed mechanical testing techniques for determining the interfacial fracture energies and sliding resistances. 相似文献
69.
In tiled Chip Multiprocessors (CMPs) last-level cache (LLC) banks are usually shared but distributed among the tiles. A static mapping of cache blocks to the LLC banks leads to poor efficiency since a block may be mapped away from the tiles actually accessing it. Dynamic policies either rely on the static mapping of blocks to a set of banks (D-NUCA) or rely on the OS to dynamically load pages to statically mapped addresses (first-touch). 相似文献
70.
Talita da Cunha Mattos Flávia Maria Santoro Kate Revoredo Vanessa Tavares Nunes 《Computers in Industry》2014
A business process is a set of activities performed in a coordinated manner within an organizational and technical environment that is aimed toward a business goal. The flexibility of a process is related to an understanding of the unexpected events that occur when people, systems and resources interact and require adjustments. Thus, business processes must be designed to respond to information about different events and their specificity. This information defines what the literature calls “context”. To broaden the perception of context in the case of a business process, this work proposes an approach to characterize the context of a business process activity in a given domain through conceptual models structured in layers. A case study was conducted to evaluate the proposal, which provided evidence of the applicability of the model. 相似文献