208 research outputs found

    Situs inversus abdominalis and duodenal atresia. A case report and review of the literature

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    Fewer than 20 patients born with situs inversus and duodenal atresia have been reported in the literature. We present a patient with this condition. A newborn baby presented shortly after birth with persistent bilious vomiting. An abdominal radiograph showed a right-sided stomach bubble and a second bubble on the left - typical of duodenal atresia but with mirror image configuration. Laparotomy confirmed the diagnosis of situs inversus abdominalis, which was also demonstrated by contrast studies and ultrasound. Duodenoduodenostomy was performed and the patient discharged on day 8 postoperatively. Situs inversus is associated with other congenital malformations including splenic malformations, left-sided liver and cardiac abnormalities; it is rarely associated with duodenal atresia. Duodenal obstruction in the presence of situs inversus has been described, including obstruction due to a web, stenosis, pre-duodenal portal vein and complete atresia. The patient presented in this paper had a duodenal web in the second part of the duodenum. Before undertaking surgery it is important to establish the presence of associated gastrointestinal and cardiac abnormalities

    Prospective Design, Rapid Prototyping, and Testing of Smart Dressings, Drug Delivery Patches, and Replacement Body Parts Using Microscopy Aided Design and ManufacturE (MADAME)

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    Natural materials exhibit smart properties including gradients in biophysical properties that engender higher order functions, as well as stimuli-responsive properties which integrate sensor and/or actuator capacities. Elucidation of mechanisms underpinning such smart material properties (i), and translation of that understanding (ii), represent two of the biggest challenges in emulating natural design paradigms for design and manufacture of disruptive materials, parts, and products. Microscopy Aided Design And ManufacturE (MADAME) stands for a computer-aided additive manufacturing platform that incorporates multidimensional (multi-D) printing and computer-controlled weaving. MADAME enables the creation of composite design motifs emulating e.g., patterns of woven protein fibers as well as gradients in different caliber porosities, mechanical, and molecular properties, found in natural tissues, from the skin on bones (periosteum) to tree bark. Insodoing, MADAME provides a means to manufacture a new genre of smart materials, products and replacement body parts that exhibit advantageous properties both under the influence of as well as harnessing dynamic mechanical loads to activate material properties (mechanoactive properties). This Technical Report introduces the MADAME technology platform and its associated machine-based workflow (pipeline), provides basic technical background of the novel technology and its applications, and discusses advantages and disadvantages of the approach in context of current 3 and 4D printing platforms

    Solar heat gains through train windows: a non-negligible contribution to the energy balance

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    The sector of transportation accounts for about one third of the total energy consumption in Switzerland. A monitoring campaign of the energy consumption of a regional train revealed the critical energy-consuming systems. Heating, cooling and ventilation were identified as major consumers. Windows are a source of non-controlled heat transfer. In summer, it may result in overheating leading to larger cooling loads while in winter, it is an important source of thermal losses. Selective double glazing and solar protection coatings can reduce these effects. Angular-dependent optical properties of a selective double glazing have been measured, and the solar heat gain coefficient (g value) was determined. An estimation of the solar gains received by a panoramic waggon was performed using the monitored solar irradiation and the measured properties of the glazing. These data were compared to the heating and cooling energy consumption monitored in this waggon. Solar gains were found to be in the same order of magnitude that the heating energy during some sunny days. They were also compared to the estimated thermal losses through the glazing and the entire envelope. These results show that the solar gains play a non-negligible role in the energy balance of the waggon. Furthermore, thermal simulations were performed to evaluate the solar gains in different conditions. It showed that 7 to 13% of energy can be saved using the glazing adapted to the climatic conditions. In addition, improving the thermal insulation of the train envelope or equipping the train with an efficient heat recovery system can lead to significant energy savings

    Entanglement of single-photons and chiral phonons in atomically thin WSe2_2

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    Quantum entanglement is a fundamental phenomenon which, on the one hand, reveals deep connections between quantum mechanics, gravity and the space-time; on the other hand, has practical applications as a key resource in quantum information processing. While it is routinely achieved in photon-atom ensembles, entanglement involving the solid-state or macroscopic objects remains challenging albeit promising for both fundamental physics and technological applications. Here, we report entanglement between collective, chiral vibrations in two-dimensional (2D) WSe2_2 host --- chiral phonons (CPs) --- and single-photons emitted from quantum dots (QDs) present in it. CPs which carry angular momentum were recently observed in WSe2_2 and are a distinguishing feature of the underlying honeycomb lattice. The entanglement results from a "which-way" scattering process, involving an optical excitation in a QD and doubly-degenerate CPs, which takes place via two indistinguishable paths. Our unveiling of entanglement involving a macroscopic, collective excitation together with strong interaction between CPs and QDs in 2D materials opens up ways for phonon-driven entanglement of QDs and engineering chiral or non-reciprocal interactions at the single-photon level

    Neuromorphic computing using non-volatile memory

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    Dense crossbar arrays of non-volatile memory (NVM) devices represent one possible path for implementing massively-parallel and highly energy-efficient neuromorphic computing systems. We first review recent advances in the application of NVM devices to three computing paradigms: spiking neural networks (SNNs), deep neural networks (DNNs), and ‘Memcomputing’. In SNNs, NVM synaptic connections are updated by a local learning rule such as spike-timing-dependent-plasticity, a computational approach directly inspired by biology. For DNNs, NVM arrays can represent matrices of synaptic weights, implementing the matrix–vector multiplication needed for algorithms such as backpropagation in an analog yet massively-parallel fashion. This approach could provide significant improvements in power and speed compared to GPU-based DNN training, for applications of commercial significance. We then survey recent research in which different types of NVM devices – including phase change memory, conductive-bridging RAM, filamentary and non-filamentary RRAM, and other NVMs – have been proposed, either as a synapse or as a neuron, for use within a neuromorphic computing application. The relevant virtues and limitations of these devices are assessed, in terms of properties such as conductance dynamic range, (non)linearity and (a)symmetry of conductance response, retention, endurance, required switching power, and device variability.11Yscopu

    A compact, multi-sensor laser scanning head for processing and monitoring micro-spot welding

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    In order to improve the reliability of micro-spot welding of metal parts in production such as e.g. in electron guns for TV picture tubes, real-time information about the evolution of the welding process should be available to allow on-line modification of the laser parameters. Such information can be derived from a set of sensors that are mounted on a laser-scanning head. Different sensors are used to monitor the optical fiber output power to determine the evolution of temperature during the spot welding process, to measure plasma emission and back-reflected laser light. A vision channel and a CCD camera are used to control the position of the laser spot on the parts to be processed. The compact scanning head is composed of a tip/tilt laser scanner, a collimating lens and a focusing lens. The scanner is fast steering, with a bandwidth of 700Hz, and can tilt by +/-3.5 degrees with a repeatability better than 50 mu rad. The settling time for maximum deflection is less than 10ms. The scanning lens is a newly developed focusing lens designed to replace commercial cumbersome scanning lenses such as F-theta lenses, which have large volume, weight and price. This lens is based on the well-known Cooke triplet design and guarantees a constant shape of the spot all over the scan surface and is specially well suited for high power beam delivery. The scan field achieved by the system is limited to 25mm x 25mm. The laser used for this application is a pulsed Nd:YAG laser delivered by an optical fiber to the optical head. However, the system can be adapted to different types of lasers. Laser micro-spot welding on copper substrate has been performed in the frame of the Brite-Euram project MAIL. Smaller tolerances (a factor of 2 less) on the spot diameters were obtained in the case of a sensor controlled operation compared to the case where sensor control is not used

    Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis

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    Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands

    Brachytic2/ZmABCB1 functions in IAA export from intercalary meristems

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    Dwarfism traits in Zea mays are regulated by multiple factors including the hormone auxin. Dwarf brachytic2 (br2) mutants harbour lesions in the gene encoding an orthologue of Arabidopsis thaliana ABCB1 which functions in auxin efflux out of meristematic regions in the shoot and root. br2 mesocotyls and coleoptiles exhibit reduced auxin transport. However, the dwarf stature of br2 derives from shortened lower internodes whilst the upper portion of the plant is completely normal. As such, it is counter-intuitive to attribute br2 dwarfism exclusively to reduced auxin export out of the shoot apex. Arabidopsis abcb1 mutants exhibit only minor reductions in auxin transport and plant height unless combined with mutations in the ABCB19 auxin transporter. Phylogenetic modelling analysis excludes the possibility that BR2 is more closely related to ABCB19 which has three more closely related orthologues in maize. BR2 is expressed in nodal meristems, and analyses of auxin transport and content indicate that BR2 function in these grass-specific tissues is analogous to ABCB1 function in the shoot and root apex of Arabidopsis. These results indicate that ABCB1/BR2 function is conserved between dicots and monocots, but also suggests that this function must be understood in the context of the segmental organization of grass plants
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