154 research outputs found

    Prevention and therapy of leg ischaemia in extracorporeal life support and extracorporeal membrane oxygenation with peripheral cannulation.

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    Extracorporeal membrane oxygenation (ECMO) and extracorporeal life support (ECLS) have been around for a long time, but it is only in recent years, with the advent of acute respiratory distress syndrome consecutive to influenza A (H1N1) infection, that these life-saving technologies have seen a broader application. Although the results of ECLS and ECMO are perceived as generally encouraging, there are still disturbing complications related to peripheral cannulation in general and, more specifically, to cannulation in the groin. The present review was designed to assess the magnitude of this latter problem, i.e. leg ischaemia related to ECLS and ECMO, in the literature and to identify strategies for possible therapies and, more importantly, prevention. The search strategy selected identified seven original articles with more than twenty patients, totalling 407 patients who underwent veno-arterial ECMO, and one large review dealing with all kinds of complications. For the original reports, the number of cases with veno-arterial support ranged from 21 to 143, with, as far as available, frequency of ischaemic complications between 11% and 52%, a reported range of surgical intervention between 9% and 22%, and a leg amputation rate from 2% to 10%. It appears that the number of reports dealing with lower extremity ischaemia during ECMO increases in parallel with the number of reports about ECMO. Strategies for early detection of peripheral ischaemia, interventions for efficient reperfusion, and measures for prevention including new concepts with smaller and eventually bidirectional arterial cannulas are discussed

    Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy

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    The properties of metal oxides, such as charge transport mechanisms or optoelectronic characteristics, can be modified by functionalization with organic molecules. This kind of organic/inorganic surface is nowadays highly regarded, in particular, for the design of hybrid devices such as dye sensitized solar cells. However, a key parameter for optimized interfaces is not only the choice of the  compounds but also the properties of adsorption. Here, we investigated the deposition of an organic dye precursor molecule on a NiO(001) single crystal surface by means of non-contact atomic force microscopy at room temperature. Depending on the coverage, single molecules, groups of  adsorbates with random or recognizable shapes, or islands of closely packed molecules were identified. Single molecules and self assemblies are resolved with sub-molecular resolution showing that they are lying flat on the surface in a trans-conformation. Within the limits of our Kelvin probe microscopy setup a charge transfer from NiO to the molecular layer of 0.3 electrons per molecules was observed only in the areas, where the molecules are closed packed

    Refining the anchor: optimizing the performance of cyclometallated ruthenium(II) dyes in p-type dye sensitized solar cells

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    A comparison of the performances of p-type dye sensitized solar cells (DSCs) sensitized by three cyclometallated ruthenium(II) dyes differing in their anchoring domains is presented. The dyes are [Ru(bpy) 2 (H 1 )] (H 3 1 = (4-(2-phenylpyridin-4-yl)phenyl)phosphonic acid) and the salts [ n Bu 4 N][Ru(bpy) 2 ( 1 )] and [Ru(bpy) 2 (H 2 )][PF 6 ] (H 2 2 = (4-(2-phenylpyridin-4-yl)phenyl)carboxylic acid). DSCs were fabricated with FTO/NiO working electrodes and either an I 2 /I 3 – /MeCN or I 2 /I 3 – /MeCN:EtCN (3:1 by volume) electrolyte. The results confirm the higher performance of dyes with a phosphonate versus carboxylic acid anchor, and reveal that [Ru(bpy) 2 (H 1 )] ( J SC = 3.24 mA cm –2 and η = 0.116%) performs better than [Ru(bpy) 2 ( 1 )] – . Electrochemical impedance spectroscopy (EIS) shows that a DSC with [Ru(bpy) 2 (H 1 )] offers the lowest transport and recombination resistances and the shortest hole lifetime and diffusion lengt

    Modular synthesis of simple cycloruthenated complexes with state-of-the-art performance in p-type DSCs

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    A modular approach based on Suzuki-Miyaura cross coupling and Miyaura borylation has been used to prepare two cyclometallated [Ru(N^N) 2 (C^N)] + complexes which possess either a carboxylic or phosphonic acid group attached via a phenylene spacer to the 4-position of the pyridine ring in the C^N ligand. The key intermediate in the synthetic pathway is [Ru(bpy) 2 ( 1 )] + where bpy = 2,2'-bipyridine and H 1 is 4-chloro-2-phenylpyridine. The crystal structure of [Ru(bpy) 2 ( 1 )][PF 6 ] is presented. Reaction of [Ru(bpy) 2 ( 1 )][PF 6 ] with 4-carboxyphenylboronic acid leads to [Ru(bpy) 2 (H 6 )][PF 6 ], while the phosphonic acid analogue is isolated as the zwitterion [Ru(bpy) 2 (H 5 )]. The cyclometallated complexes have been characterized by mass spectrometry, multinuclear NMR spectroscopy, absorption spectroscopy and electrochemistry. [Ru(bpy) 2 ( 5 )] adsorbs onto NiO FTO/NiO electrodes (confirmed by solid-state absorption spectroscopy) and its performance in p-type dye-sensitized solar cells (DSCs) has been compared to that of the standard dye P1; two-screen printed layers of NiO give better DSC performances than one layer. Duplicate DSCs containing [Ru(bpy) 2 (H 5 )] achieve short-circuit current densities ( J SC ) of 3.38 and 3.34 mA cm –2 and photoconversion efficiencies ( η ) of 0.116 and 0.109%, respectively, compared to values of J SC = 1.84 and 1.96 mA cm –2 and η = 0.057 and 0.051% for P1. Despite its simple dye structure, the performance of [Ru(bpy) 2 (H 5 )] parallels the best-performing cyclometallated ruthenium(II) dye in p-type DSCs reported previously (He et al , J. Phys. Chem. C , 2014, 118 , 16518) and confirms the effectiveness of a phosphonic acid anchor in the dye and the attachment of the anchoring unit to the pyridine (rather than phenyl) ring of the cyclometallating ligan

    Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001)

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    Properties of metal oxides, such as optical absorption, can be influenced through the sensitization with molecular species that absorb visible light. Molecular/solid interfaces of this kind are particularly suited for the development and design of emerging hybrid technologies such as dye-sensitized solar cells. A key optimization parameter for such devices is the choice of the compounds in order to control the direction and the intensity of charge transfer across the interface. Here, the deposition of two different molecular dyes, porphyrin and coumarin, as single-layered islands on a NiO(001) single crystal surface have been studied by means of non-contact atomic force microscopy at room temperature. Comparison of both island types reveals different adsorption and packing of each dye, as well as an opposite charge-transfer direction, which has been quantified by Kelvin probe force microscopy measurements

    Management goals for type 1 Gaucher disease: An expert consensus document from the European working group on Gaucher disease

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    AbstractGaucher Disease type 1 (GD1) is a lysosomal disorder that affects many systems. Therapy improves the principal manifestations of the condition and, as a consequence, many patients show a modified phenotype which reflects manifestations of their disease that are refractory to treatment. More generally, it is increasingly recognised that information as to how a patient feels and functions [obtained by patient- reported outcome measurements (PROMs)] is critical to any comprehensive evaluation of treatment. A new set of management goals for GD1 in which both trends are reflected is needed. To this end, a modified Delphi procedure among 25 experts was performed. Based on a literature review and with input from patients, 65 potential goals were formulated as statements. Consensus was considered to be reached when ≥75% of the participants agreed to include that specific statement in the management goals. There was agreement on 42 statements. In addition to the traditional goals concerning haematological, visceral and bone manifestations, improvement in quality of life, fatigue and social participation, as well as early detection of long-term complications or associated diseases were included. When applying this set of goals in medical practice, the clinical status of the individual patient should be taken into account

    Analysis of performance in Depth Based Routing for Underwater Wireless Sensor Networks

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    In the last decade, Underwater Wireless Sensor Networks (UWSNs) have been widely studied because of their peculiar aspects that distinguish them from common wireless terrestrial networks. In fact, most UWSNs use acoustic instead of radio-frequency based communications, and nodes are subject to high mobility caused by water currents. As a consequence, specialized routing algorithms have been developed to tackle this challenging scenario. Depth based Routing (DBR) is one of the first protocols that have been developed to this aim, and is still widely adopted in actual implementations of UWSNs. In this paper we propose a stochastic analysis that aims at evaluating the performance of UWSNs using DBR in terms of expected energy consumption and expected end-to-end delay. Under a set of assumptions, we give expressions for these performance indices that can be evaluated efficiently, and hence they can be adopted as the basis for optimizing the configuration parameters of the protocol

    An Iterated Local Search Approach for Finding Provably Good Solutions for Very Large TSP Instances

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    Abstract. Meta-heuristics usually lack any kind of performance guar-antee and therefore one cannot be certain whether the resulting solutions are (near) optimum solutions or not without relying on additional algo-rithms for providing lower bounds (in case of minimization). In this paper, we present a highly effective hybrid evolutionary local search algorithm based on the iterated Lin-Kernighan heuristic combined with a lower bound heuristic utilizing 1-trees. Since both upper and lower bounds are improved over time, the gap between the two bounds is minimized by means of effective heuristics. In experiments, we show that the proposed approach is capable of finding short tours with a gap of 0.8 % or less for TSP instances up to 10 million cities. Hence, to the best of our knowledge, we present the first evolutionary algorithm and meta-heuristic in general that delivers provably good solutions and is highly scalable with the problem size. We show that our approach outperforms all existing heuristics for very large TSP instances.
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