196 research outputs found

    Optimization of hybrid sol-gel coating for dropwise condensation of pure steam

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    We developed hybrid organic-inorganic sol-gel silica coatings with good durability in harsh environment (high temperatures, high vapor velocities) and with slightly hydrophobic behavior, sufficient to promote dropwise condensation (DWC) of pure steam. DWC is a very promising mechanism in new trends of thermal management and power generation systems to enhance the heat transfer during condensation as compared to film-wise condensation (FWC). The sol-gel coatings have been prepared from methyl triethoxy silane (MTES) and tetraethyl-orthosilicate (TEOS) and deposited on an aluminum substrate. The coatings were optimized in terms of precursor ratio and annealing temperature highlighting potentials and limits of such mixtures. A comprehensive surface characterization before and after saturated steam condensation tests has been performed and related to the thermal measurements for evaluating the heat transfer augmentation as compared to FWC obtained on untreated aluminum surfaces. The results showed that the developed hybrid organic-inorganic sol-gel silica coatings are promising DWC promoters

    Electrical expression of spin accumulation in ferromagnet/semiconductor structures

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    We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.Comment: A review to appear in Mod. Phys. Lett.

    Serverification of Molecular Modeling Applications: the Rosetta Online Server that Includes Everyone (ROSIE)

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    The Rosetta molecular modeling software package provides experimentally tested and rapidly evolving tools for the 3D structure prediction and high-resolution design of proteins, nucleic acids, and a growing number of non-natural polymers. Despite its free availability to academic users and improving documentation, use of Rosetta has largely remained confined to developers and their immediate collaborators due to the code's difficulty of use, the requirement for large computational resources, and the unavailability of servers for most of the Rosetta applications. Here, we present a unified web framework for Rosetta applications called ROSIE (Rosetta Online Server that Includes Everyone). ROSIE provides (a) a common user interface for Rosetta protocols, (b) a stable application programming interface for developers to add additional protocols, (c) a flexible back-end to allow leveraging of computer cluster resources shared by RosettaCommons member institutions, and (d) centralized administration by the RosettaCommons to ensure continuous maintenance. This paper describes the ROSIE server infrastructure, a step-by-step 'serverification' protocol for use by Rosetta developers, and the deployment of the first nine ROSIE applications by six separate developer teams: Docking, RNA de novo, ERRASER, Antibody, Sequence Tolerance, Supercharge, Beta peptide design, NCBB design, and VIP redesign. As illustrated by the number and diversity of these applications, ROSIE offers a general and speedy paradigm for serverification of Rosetta applications that incurs negligible cost to developers and lowers barriers to Rosetta use for the broader biological community. ROSIE is available at http://rosie.rosettacommons.org

    Simultaneous Interpreting : Characteristic of Autonomic Provision of Extreme Cognitive Loads

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    Simultaneous interpreting is one of the most comprehensive and energy-consuming types of cognitive activity. To work successfully, a simultaneous interpreter must have a specific functional state. The aim of our study was to find out the basic mechanisms of this functional state, the effect of the simultaneous interpreting on cognitive function changes, and the main factors influencing the degree of the regulatory systems strain. Materials and Methods. 33 individuals participated in the study: 22 linguists specially trained in simultaneous translation composed the experimental group and 11 language-qualified people having no skills of simultaneous translation represented the control group. In compliance with the study design, the measurements were performed under the conditions similar to the real work of simultaneous interpreters: the participants working in succession performed professional tasks: shadowing in the native and foreign languages (German and English), simultaneous interpretation of the reports from the native language to the foreign, and vice versa. The interpreters were psychologically tested using ApWay.ru Web platform before and after the performance on the professional tasks: computer campimetry, test for a simple sensorimotor activity, Stroop test, and test for emotional disadaptation level. Cardiointervalogram was telemetrically recorded during the entire experiment. Results. Some specific aspects of autonomic provision of simultaneous interpreting have been unraveled. A significantly greater tension of the autonomic regulation is manifested by the simultaneous interpreters compared to the control group. It was most prominent when translation was done from the foreign language. The total level of stress during the performance on the linguistic tasks appeared to be higher in the control group. In the simultaneous interpreters, in contrast to the control group, there was registered a high activity level of the sympathetic and parasympathetic systems and a marked integration of the cardiac rhythm regulation circuits over the entire period of performing the linguistic tasks. The psychological tests have demonstrated a significantly more confident cognitive control relative to the control group. Thus, a specific functional system has been formed in the simultaneous interpreters providing a successful interaction of various information images (or codes) and consolidation of autonomic and cognitive resources during the performance on professional tasks. Lack of the necessary skills and, consequently, of the task-oriented functional system in the participants of the control group resulted in the enhancement of the non-specific (less effective) stress response.Peer reviewe

    Aortic dissection type I in a weightlifter with hypertension: A case report

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    Acute aortic dissection can occur at the time of intense physical exertion in strength-trained athletes like weightlifters, bodybuilders, throwers, and wrestlers

    Delayed-onset heparin-induced thrombocytopenia presenting with multiple arteriovenous thromboses: case report

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    <p>Abstract</p> <p>Background</p> <p>Delayed-onset heparin-induced thrombocytopenia with thrombosis, albeit rare, is a severe side effect of heparin exposure. It can occur within one month after coronary artery bypass grafting (CABG) with manifestation of different thrombotic events.</p> <p>Case presentation</p> <p>A 59-year-old man presented with weakness, malaise, bilateral lower limb pitting edema and a suspected diagnosis of deep vein thrombosis 18 days after CABG. Heparin infusion was administered as an anticoagulant. Clinical and paraclinical work-up revealed multiple thrombotic events (stroke, renal failure, deep vein thrombosis, large clots in heart chambers) and 48 ×10<sup>3</sup>/ÎŒl platelet count, whereupon heparin-induced thrombocytopenia was suspected. Heparin was discontinued immediately and an alternative anticoagulant agent was administered, as a result of which platelet count recovered. Heparin-induced thrombocytopenia, which causes thrombosis, is a serious side effect of heparin therapy. It is worthy of note that no case of delayed-onset heparin-induced thrombocytopenia with thrombosis associated with cardiopulmonary bypass surgery has thus far been reported in Iran.</p> <p>Conclusion</p> <p>Delayed-onset heparin-induced thrombocytopenia should be suspected in any patient presenting with arterial or venous thromboembolic disorders after recent heparin therapy, even though the heparin exposure dates back to more than a week prior to presentation; and it should be ruled-out before the initiation of heparin therapy.</p

    Evidence of atmospheric nanoparticle formation from emissions of marine microorganisms

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    International audienceEarth, as a whole, can be considered as a living organism emitting gases and particles into its atmosphere, in order to regulate its own temperature. In particular, oceans may respond to climate change by emitting particles that ultimately will inïŹ‚uence cloud coverage. At the global scale, a large fraction of the aerosol number concentration is formed by nucleation of gas-phase species, but this process has never been directly observed above oceans. Here we present, using semicontrolled seawater-air enclosures, evidence that nucleation may occur from marine biological emissions in the atmosphere of the open ocean. We identify iodine-containing species as major precursors for new particle clusters’ formation, while questioning the role of the commonly accepted dimethyl sulïŹde oxidation products, in forming new particle clusters in the region investigated and within a time scale on the order of an hour. We further show that amines would sustain the new particle formation process by growing the new clusters to larger sizes. Our results suggest that iodine-containing species and amines are correlated to different biological tracers. These observations, if generalized, would call for a substantial change of modeling approaches of the sea-to-air interactions

    Design and characteristics of the prophylactic intra-operative ventricular arrhythmia ablation in high-risk LVAD candidates (PIVATAL) trial

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    BACKGROUND: The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra-operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant. METHODS: We designed a prospective, multicenter, open-label, randomized-controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra-operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life. CONCLUSION: The primary aim of this first-ever randomized trial is to assess the efficacy of intra-operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA

    Molecular Approach to the Identification of Fish in the South China Sea

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    BACKGROUND: DNA barcoding is one means of establishing a rapid, accurate, and cost-effective system for the identification of species. It involves the use of short, standard gene targets to create sequence profiles of known species against sequences of unknowns that can be matched and subsequently identified. The Fish Barcode of Life (FISH-BOL) campaign has the primary goal of gathering DNA barcode records for all the world's fish species. As a contribution to FISH-BOL, we examined the degree to which DNA barcoding can discriminate marine fishes from the South China Sea. METHODOLOGY/PRINCIPAL FINDINGS: DNA barcodes of cytochrome oxidase subunit I (COI) were characterized using 1336 specimens that belong to 242 species fishes from the South China Sea. All specimen provenance data (including digital specimen images and geospatial coordinates of collection localities) and collateral sequence information were assembled using Barcode of Life Data System (BOLD; www.barcodinglife.org). Small intraspecific and large interspecific differences create distinct genetic boundaries among most species. In addition, the efficiency of two mitochondrial genes, 16S rRNA (16S) and cytochrome b (cytb), and one nuclear ribosomal gene, 18S rRNA (18S), was also evaluated for a few select groups of species. CONCLUSIONS/SIGNIFICANCE: The present study provides evidence for the effectiveness of DNA barcoding as a tool for monitoring marine biodiversity. Open access data of fishes from the South China Sea can benefit relative applications in ecology and taxonomy

    Deep-Sea Fish Distribution Varies between Seamounts: Results from a Seamount Complex off New Zealand

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    Fish species data from a complex of seamounts off New Zealand termed the “Graveyard Seamount Complex’ were analysed to investigate whether fish species composition varied between seamounts. Five seamount features were included in the study, with summit depths ranging from 748–891 m and elevation from 189–352 m. Measures of fish species dominance, rarity, richness, diversity, and similarity were examined. A number of factors were explored to explain variation in species composition, including latitude, water temperature, summit depth, depth at base, elevation, area, slope, and fishing effort. Depth at base and slope relationships were significant with shallow seamounts having high total species richness, and seamounts with a more gradual slope had high mean species richness. Species similarity was modelled and showed that the explanatory variables were driven primarily by summit depth, as well as by the intensity of fishing effort and elevation. The study showed that fish assemblages on seamounts can vary over very small spatial scales, in the order of several km. However, patterns of species similarity and abundance were inconsistent across the seamounts examined, and these results add to a growing literature suggesting that faunal communities on seamounts may be populated from a broad regional species pool, yet show considerable variation on individual seamounts
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