325 research outputs found

    A Pipeline Analog-To-Digital Converter for a Plasma Impedance Probe

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    Space instrumentation technology is an essential tool for rocket and satellite research, and is expected to become popular in commercial and military operations in fields such as radar, imaging, and communications. These instruments are traditionally implemented on printed circuit boards using discrete general-purpose Analog-to-Digital Converter (ADC) devices and other components. A large circuit board is not convenient for use in micro-satellite deployments, where the total payload volume is limited to roughly one cubic foot. Because micro-satellites represent a fast growing trend in satellite research and development, there is motivation to explore miniaturized custom application-specific integrated circuit (ASIC) designs to reduce the volume and power consumption occupied by instrument electronics. In this thesis, a model of a new Plasma Impedance Probe (PIP) architecture, which utilizes a custom-built ADC along with other analog and digital components, is proposed. The model can be fully integrated to produce a low-power, miniaturized impedance probe

    Oligochaeta, Naididae of the West Indies and adjacent regions

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    A very large collection of Naididae of the West Indies (153 localities), Suriname (15), Venezuela (2) and Florida (1) is studied. Five new species Nais barua, Dero scalariformis, D. tuna, Aulophorus kalina, A. barbatus are described. Dero magna, D. trifida, Aulophorus tridentatus, Allonais japonica, Pristina sima are redescribed. The 46 Naididae species of the West Indies are discussed by their taxonomy, distribution and habitat

    A time-extended Hamiltonian formalism

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    A Poisson structure on the time-extended space R x M is shown to be appropriate for a Hamiltonian formalism in which time is no more a privileged variable and no a priori geometry is assumed on the space M of motions. Possible geometries induced on the spatial domain M are investigated. An abstract representation space for sl(2,R) algebra with a concrete physical realization by the Darboux-Halphen system is considered for demonstration. The Poisson bi-vector on R x M is shown to possess two intrinsic infinitesimal automorphisms one of which is known as the modular or curl vector field. Anchored to these two, an infinite hierarchy of automorphisms can be generated. Implications on the symmetry structure of Hamiltonian dynamical systems are discussed. As a generalization of the isomorphism between contact flows and their symplectifications, the relation between Hamiltonian flows on R x M and infinitesimal motions on M preserving a geometric structure therein is demonstrated for volume preserving diffeomorphisms in connection with three-dimensional motion of an incompressible fluid.Comment: 14 pages, late

    Osteochondral transfer using a transmalleolar approach for arthroscopic management of talus posteromedial lesions

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    SummaryCharacterizing osteochondral lesions of the talus has enabled the strategies of surgical management to be better specified. The main technical problem is one of access for arthroscopy instruments to posteromedial lesions. A range of techniques and approaches has been described in ankle arthroscopy in general, and a transmalleolar approach provides reliable and efficient access in these cases. It is frequently used for transchondral drilling, but also enables satisfactory implant positioning in autologous osteochondral mosaicplasty procedures. We report our technique and results on five cases with a minimum 1.2 years’ follow-up

    In Vitro Cytotoxicity of 198Au-NPs Labeled HIV-1 Tat CPP for the Treatment of Metastatic Breast Cancer

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    The present research advances the area of targeted radionuclide therapy (TRT) by using nanoparticles as intrinsic carriers of radionuclides. In here we proposed the use of nuclear nanotechnologies where nanoparticle cores serve as super-carriers of radionuclides, potentially yielding new endo-radiotherapy agents with a higher safety and efficacy profile than those currently used in TRT. We studied a new original concept in TRT by introducing radioactive gold nanoparticles as carriers of the therapeutic payload while increasing the number of radioactive atoms per tumor cell. By separating the radionuclide from the targeting agent, it was possible to avoid the severe effects of radiolysis in molecular decomposition of the targeting agent, which is currently a limiting factor in TRT. We studied under this paradigm the beta-particle emitter 198Au (t1/2 = 2.69 d). Using radioactive gold Au-198 (t1/2 = 2.69 d) as a therapeutic load and the cationic cell penetrating peptide (CPP) HIV-1 Tat as a targeting agent, we developed the 198Au-AuNP HIV-1 Tat as a therapeutic strategy for the treatment of breast cancer metastases. The breast cancer cell line SKBr-3 was used to test the cytotoxicity of 198Au-AuNP HIV-1 Tat with different activity concentrations for an incubation time of 12 hours. The Real Time Cell Analyzer (RTCA) was used to quantitate the cell growth or delay as a function of time. When compared to controls, a delay in cell growth was observed for wells that were administered an activity of 1000 and 1500 kBq whereas no significant changes were observed for 50, 100 and 500 kBq. The effect of functionalized 198AuNP-HIV1-Tat was observed to have a small effect in cell growth when compared with 198AuNP alone. Moreover, cell growth delay was compared with that obtained using external beam radiation therapy (2 Gy) and the chemotherapy agent doxorubicin. Results indicated that 198Au-AuNP HIV-1 Tat at 5000 kBq was similar in toxicity to external beam therapy and lower than doxorubicin. We predict the use of cell penetrating peptides in combination with intrinsically radioactive nanoparticles as a new strategy against metastatic breast cancer

    Evaluation of Anisotropic Conductive Films Based on Vertical Fibers for Post-CMOS Wafer-Level Packaging

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    In this paper, we investigate the mechanical and electrical properties of an anisotropic conductive film (ACF) on the basis of high-density vertical fibers for a wafer-level packaging (WLP) application. As part of the WaferBoard, a\ud reconfigurable circuit platform for rapid system prototyping,\ud ACF is used as an intermediate film providing compliant and\ud vertical electrical connection between chip contacts and a top surface of an active wafer-size large-area IC. The chosen ACF is first tested by an indentation technique. The results show that the elastic–plastic deformation mode as well as the Young’s modulus and the hardness depend on the indentation depth. Second, the efficiency of the electrical contact is tested using a uniaxial compression on a stack comprising a dummy ball grid array (BGA) board, an ACF, and a thin Al film. For three bump diameters, as the compression increases, the resistance values decrease before reaching low and stable values. Despite the BGA solder bumps exhibit plastic deformation after compression, no damage is found on the ACF film. These results show that vertical fiber ACFs can be used for nonpermanent bonding in a WLP application

    Selection of Composable Web Services Driven by User Requirements

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    International audienceBuilding a composite application based on Web services has become a real challenge regarding the large and diverse service space nowadays. Especially when considering the various functional and non-functional capabilities that Web services may afford and users may require. In this paper, we propose an approach for facilitating Web service selection according to user requirements. These requirements specify the needed functionality and expected QoS, as well as the composability between each pair of services. The originality of our approach is embodied in the use of Relational Concept Analysis (RCA), an extension of Formal Concept Analysis (FCA). Using RCA, we classify services by their calculated QoS levels and composability modes. We use a real case study of 901 services to show how to accomplish an efficient selection of services satisfying a specified set of functional and non-functional requirements

    Smart glass film reduced ascorbic acid in red and orange capsicum fruit cultivars without impacting shelf life

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    Smart Glass Film (SGF) is a glasshouse covering material designed to permit 80% trans-mission of photosynthetically active light and block heat-generating solar energy. SGF can reduce crop water and nutrient consumption and improve glasshouse energy use efficiency yet can reduce crop yield. The effect of SGF on the postharvest shelf life of fruits remains unknown. Two capsicum varieties, Red (Gina) and Orange (O06614), were cultivated within a glasshouse covered in SGF to assess fruit quality and shelf life during the winter season. SGF reduced cuticle thickness in the Red cultivar (5%) and decreased ascorbic acid in both cultivars (9–14%) without altering the overall morphology of the mature fruits. The ratio of total soluble solids (TSSs) to titratable acidity (TA) was significantly higher in Red (29%) and Orange (89%) cultivars grown under SGF. The Red fruits had a thicker cuticle that reduced water loss and extended shelf life when compared to the Orange fruits, yet neither water loss nor firmness were impacted by SGF. Reducing the storage temperature to 2◦C and increasing relative humidity to 90% extended the shelf life in both cultivars without evidence of chilling injury. In summary, SGF had minimal impact on fruit development and postharvest traits and did not compromise the shelf life of mature fruits. SGF provides a promising technology to block heat-generating solar radiation energy without affecting fruit ripening and marketable quality of capsicum fruits grown during the winter season
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