1,834 research outputs found
collected from South and South-eastern regions of Turkey
A total of 45 lizards (Acanthodactylus harranensis [n = 15], Acanthodacthylus schreiberi [n = 9] and Mesalina brevirostris [n = 21]) were collected from South and Southeastern Regions of Turkey and examined for helminth fauna. Acanthodactylus harranensis harbored 1 species of Nematoda (Skrjabinodon sp.), 1 species of Cestoda (Oochoristica tuberculata) and 1 species of Acanthocephala (Centrorhynchus sp. [cystacanth]). Acanthodactylus schreiberi harbored unidentified cysticercoids. Mesalina brevirostris harbored 1 species of Nematoda (Spauligodon saxicolae). All lizards represents new host records for the helminths reported in this study
A Modular, Real-Time Fieldbus Architecture for Mobile Robotic Platforms
Cataloged from PDF version of article.The design and construction of complex and reconfigurable embedded systems such as small autonomous mobile robots is a challenging task that involves the selection, interfacing, and programming of a large number of sensors and actuators. Facilitating this tedious process requires modularity and extensibility both in hardware and software components. In this paper, we introduce the universal robot bus (URB), a real-time fieldbus architecture that facilitates rapid integration of heterogeneous sensor and actuator nodes to a central processing unit (CPU) while providing a software abstraction that eliminates complications arising from the lack of hardware homogeneity. Motivated by our primary application area of mobile robotics, URB is designed to be very lightweight and efficient, with real-time support for Recommended Standard (RS) 232 or universal serial bus connections to a central computer and inter-integrated circuit (I(2)C), controller area network, or RS485 bus connections to embedded nodes. It supports automatic synchronization of data acquisition across multiple nodes, provides high data bandwidth at low deterministic latencies, and includes flexible libraries for modular software development both for local nodes and the CPU. This paper describes the design of the URB architecture, provides a careful experimental characterization of its performance, and demonstrates its utility in the context of its deployment in a legged robot platform
Static secondary ion mass spectrometry (S-SIMS) for the characterization of surface components in mineral particulates
Inversion Charge-boost and Transient Steep-slope induced by Free charge-polarization Mismatch in a Ferroelectric-metal-oxide-semiconductor Capacitor
In this letter, the transient behavior of a ferroelectric (FE)
metal-oxide-semiconductor (MOS) capacitor is theoretically investigated with a
series resistor. It is shown that compared to a conventional high-k dielectric
MOS capacitor, a significant inversion charge-boost can be achieved by a FE MOS
capacitor due to a steep transient subthreshold swing (SS) driven by the free
charge-polarization mismatch. It is also shown that the observation of steep
transient SS significantly depends on the viscosity coefficient under Landau's
mean field theory, in general representing the average FE time response
associated with domain nucleation and propagation. Therefore, this letter not
only establishes a theoretical framework that describes the physical origin
behind the inversion charge-boost in a FE MOS capacitor, but also shows that
the key feature of depolarization effect on a FE MOS capacitor should be the
inversion-charge boost, rather than the steep SS (e.g., sub-60mV/dec at room
temperature), which cannot be experimentally observed as the measurement time
is much longer than the FE response. Finally, we outlines the required material
targets for the FE response in field-effect transistors to be applicable for
next-generation high-speed and low-power digital switches.Comment: 6 figures, 5 pages, submitted to IEEE JxCD
Phase relations in K_xFe_{2-y}Se_2 and the structure of superconducting K_xFe_2Se_2 via high-resolution synchrotron diffraction
Superconductivity in iron selenides has experienced a rapid growth, but not
without major inconsistencies in the reported properties. For
alkali-intercalated iron selenides, even the structure of the superconducting
phase is a subject of debate, in part because the onset of superconductivity is
affected much more delicately by stoichiometry and preparation than in cuprate
or pnictide superconductors. If high-quality, pure, superconducting
intercalated iron selenides are ever to be made, the intertwined physics and
chemistry must be explained by systematic studies of how these materials form
and by and identifying the many coexisting phases. To that end, we prepared
pure K_2Fe_4Se_5 powder and superconductors in the K_xFe_{2-y}Se_2 system, and
examined differences in their structures by high-resolution synchrotron and
single-crystal x-ray diffraction. We found four distinct phases: semiconducting
K_2Fe_4Se_5, a metallic superconducting phase K_xFe_2Se_2 with x ranging from
0.38 to 0.58, an insulator KFe_{1.6}Se_2 with no vacancy ordering, and an
oxidized phase K_{0.51(5)}Fe_{0.70(2)}Se that forms the PbClF structure upon
exposure to moisture. We find that the vacancy-ordered phase K_2Fe_4Se_5 does
not become superconducting by doping, but the distinct iron-rich minority phase
K_xFe_2Se_2 precipitates from single crystals upon cooling from above the
vacancy ordering temperature. This coexistence of metallic and semiconducting
phases explains a broad maximum in resistivity around 100 K. Further studies to
understand the solubility of excess Fe in the K_xFe_{2-y}Se_2 structure will
shed light on the maximum fraction of superconducting K_xFe_2Se_2 that can be
obtained by solid state synthesis.Comment: 12 pages, 16 figures, supplemental materia
Spin transport in as-grown and annealed thulium iron garnet/platinum bilayers with perpendicular magnetic anisotropy
We characterize the spin Hall magnetoresistance (SMR), spin Seebeck effect (SSE), and dampinglike spin-orbit torque (SOT) in thulium iron garnet/platinum bilayers with perpendicular magnetic anisotropy by using harmonic Hall effect measurements. By consecutive annealing steps followed by measurements on a single device, we reveal that the spin-dependent effects gradually decrease in amplitude as the annealing temperature increases. We attribute this behavior primarily to the changes in the spin-mixing conductance, which sensitively depends on the interface quality. However, further analysis demonstrates that although the SSE scales closely with the SMR, the dampinglike SOT shows a significantly different trend upon annealing, contrary to theoretical expectations. By comparing the dampinglike SOT with the field-induced Hall effect, we found evidence that scattering from Fe impurities in the Pt at the interface might be responsible for the distinct annealing temperature dependence of the dampinglike SOT.Deutsche ForschungsgemeinschaftUnited States. Defense Advanced Research Projects Agency (C-SPIN, a SRC STARnet Center)Microelectronics Advanced Research Corporation (MARCO) (C-SPIN, a SRC STARnet Center
A textile platform using mechanically reinforced hydrogel fibres towards engineering tendon niche
INTRODUCTION: Tendon injuries can result from tendon overuse or trauma, resulting in substantial pain and disability. Given that natural or surgical repair of tendons lead to a poor outcome in terms of mechanical properties and functionality, there is a great need for tissue engineering strategies. Textile platforms enable the generation of biomimetic constructs [1]. Therefore, the main goal of this study is the development of cell-laden hybrid hydrogel fibers reinforced with a mechanically robust core fiber and their assembly into braided constructs towards replicating tendon mechanical properties and architecture. METHODS: To fabricate mechanically reinforced hydrogel fibres, a commercially available suture was coated using a cell-hydrogel mixture of methacryloyl gelatine (GelMA) and alginate. Composite fibres (CFs) were obtained by ionic crosslinking of alginate followed by photocrosslinking of GelMA. CFs were assembled using braiding technique and the mechanical properties of single fibres and braided constructs were evaluated. Different cells were encapsulated in the hydrogel layer, including MC-3T3, mesenchymal stem cells (MSCs) and human tendon-derived cells (TDCs). Cell viability and metabolic activity were evaluated by LIVE/DEAD staining and presto blue assay of metabolic activity. The expression of tendon-related markers and matrix deposition were also investigated. RESULTS: CFs were fabricated with a GelMA:alginate hydrogel layer and using multifilament twisted cotton or biodegradable suturing threads. The biocompatibility of this system was evaluated on encapsulated cells (Fig.1a). Cells (MC-3T3, MSCs and TDCs) were homogeneously distributed along the hydrogel layer, being viable up to 14 days in culture. In addition, TDCs were spreading inside the hydrogel after less than 48 h. Moreover, to further improve the mechanical properties of CFs, braided constructs were generated (Fig. 1b). Braiding CFs together enhanced their tensile strength and the process did not affect the viability of encapsulated cells.DISCUSSION & CONCLUSIONS: CFs were generated with a load bearing core and a hydrogel layer towards mimicking both mechanical properties and the matrix-rich microenvironment of tendon tissue. Accordingly, cell behaviour can be further modulated by modifying the hydrogel composition or, ultimately, through the addition of bioactive cues. Finally, braiding CFs together allows tuning the mechanical properties of developed constructs to match those of native tendon tissues.Fundação para a Ciência e a Tecnologia in the framework of FCT-POPH-FSE, the PhD grant SFRH/BD/96593/2013 of R.C-
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