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1 Fibrosis imaging: Current concepts and future directions 2017-11-21

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Publication date: Available online 3 November 2017

Author(s): Maike Baues, Anshuman Dasgupta, Josef Ehling, Jai Prakash, Peter Boor, Frank Tacke, Fabian Kiessling, Twan Lammers

Fibrosis plays an important role in many different pathologies. It results from tissue injury, chronic inflammation, autoimmune reactions and genetic alterations, and it is characterized by the excessive deposition of extracellular matrix components. Biopsies are routinely employed for fibrosis diagnosis, but they suffer from several drawbacks, including their invasive nature, sampling variability and limited spatial information. To overcome these limitations, multiple different imaging tools and technologies have been evaluated over the years, including X-ray imaging, computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), positron emission tomography (PET) and single-photon emission computed tomography (SPECT). These modalities can provide anatomical, functional and molecular imaging information which is useful for fibrosis diagnosis and staging, and they may also hold potential for the longitudinal assessment of therapy responses. Here, we summarize the use of non-invasive imaging techniques for monitoring fibrosis in systemic autoimmune diseases, in parenchymal organs (such as liver, kidney, lung and heart), and in desmoplastic cancers. We also discuss how imaging biomarkers can be integrated in (pre-) clinical research to individualize and improve anti-fibrotic therapies.

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2 A fast isogeometric BEM for the three dimensional Laplace- and Helmholtz problems 2017-11-21

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Publication date: 1 March 2018
Source:Computer Methods in Applied Mechanics and Engineering, Volume 330

Author(s): Jürgen Dölz, Helmut Harbrecht, Stefan Kurz, Sebastian Schöps, Felix Wolf

We present an indirect higher order boundary element method utilising NURBS mappings for exact geometry representation and an interpolation-based fast multipole method for compression and reduction of computational complexity, to counteract the problems arising due to the dense matrices produced by boundary element methods. By solving Laplace and Helmholtz problems via a single layer approach we show, through a series of numerical examples suitable for easy comparison with other numerical schemes, that one can indeed achieve extremely high rates of convergence of the pointwise potential through the utilisation of higher order B-spline-based ansatz functions.

3 Analytical inverse heat transfer method for temperature-sensitive-coating measurement on a finite base 2017-11-17

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Publication date: March 2018
Source:International Journal of Heat and Mass Transfer, Volume 118

Author(s): Tianshu Liu, Javier Montefort, Scott Stanfield, Steve Palluconi, Jim Crafton, Zemin Cai

An analytical inverse heat transfer solution is given for calculating surface heat flux from temperature-sensitive coating measurements on a base with a finite thickness, which is particularly relevant to high enthalpy hypersonic wind tunnel experiments. This solution is validated through simulations for several time histories of the heat flux imposed on the surface of the base, focusing on the effects of the relevant parameters including the control parameter in the inverse Laplace transform, base thickness and convective heat transfer on the backside of the base. Further, this solution is used to extract the heat-flux fields from temperature-sensitive-paint images obtained on a flat surface of an aluminum base in a transonic obliquely impinging jet. The experimental data exhibit the self-similar evolution of the surface temperature and heat-flux fields. The Nusselt number distribution evaluated by using this analytical method is consistent with the previous results.

4 On the history of the early meteoritic bombardment of the Moon: Was there a terminal lunar cataclysm? 2017-11-16

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Publication date: 1 March 2018
Source:Icarus, Volume 302

Author(s): Greg Michael, Alexander Basilevsky, Gerhard Neukum

This work revisits the hypothesis of the so-called ‘lunar terminal cataclysm’ suggested by Tera et al. (1973, 1974) as a strong peak in the meteorite bombardment of the Moon around 3.9 Ga ago. According to the hypothesis, most of the impact craters observed on the lunar highlands formed during this short time period and thus formed the majority of the lunar highland impact breccias and melts. The hypothesis arose from the observation that the ages of highland samples from all the lunar missions are mostly grouped around 3.9–4.0 Ga. Since those missions, however, radiometric dating techniques have progressed and many samples, both old and new, have been re-analyzed. Nevertheless, the debate over whether there was a terminal cataclysm persists. To progress in this problem we summarized results of 269 K–Ar datings (mostly made using the 40Ar–39Ar technique) of highland rocks represented by the Apollo 14, 15, 16, 17 and Luna 20 samples and 94 datings of clasts of the highland rocks from 23 lunar meteorites representing 21 localities on the lunar surface, and considered them jointly with the results of our modelling of the cumulative effect of the impact gardening process on the presence of impact melt of different ages at the near-surface of the Moon. The considered results of K–Ar dating of the Apollo-Luna samples of lunar highland rocks confirmed a presence of strong peak centered at 3.87 Ga. But since the time when the hypothesis of terminal cataclysm was suggested, it has become clear that this peak could be a result of sampling bias: it is the only prominent feature at the sites with an apparent domination of Imbrium basin ejecta (Apollo 14 and 15) and the age pattern is more complicated for the sites influenced not only by Imbrium ejecta but also that of other basins (Nectaris at the Apollo 16 site and Serenitatis at the Apollo 17 site). Our modelling shows that the cataclysm, if it occurred, should produce a strong peak in the measured age values but we see in the considered histograms and relative probability plots not only the 3.87 Ga peak (due to Imbrium basin), but also several secondary peaks caused by the formation of other basins distributed between 3.87 and 4.25 Ga. The lunar terminal cataclysm hypothesis is in disagreement with the distribution of K–Ar ages for the highland rocks of the lunar meteorites. The population of lunar meteorites representing localities randomly distributed over the lunar surface, and thus free from the mentioned sampling bias, shows no ∼3.9 Ga peak as it should, if the cataclysm did occur. We conclude that the statistics of sample ages contradict the terminal cataclysm scenario in the bombardment of the Moon. We also see evidence for the formation of several impact basins between 3.87 and 4.25 Ga which is likewise incompatible with the hypothesis of a short interval cataclysm. There remain other basins, including the largest South Pole – Aitken, the ages of which should be determined in future studies to further clarify the impact history. Sample-return missions targeted to date several key basins need to be planned, and the continued study of lunar meteorites may also bring new details to the general view of the impact bombardment of the Moon.

5 Comparison of extrusion and co-extrusion encapsulation techniques to protect Lactobacillus acidophilus LA3 in simulated gastrointestinal fluids 2017-11-16

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Publication date: March 2018
Source:LWT - Food Science and Technology, Volume 89

Author(s): Marluci P. Silva, Fabrício L. Tulini, Evandro Martins, Manfred Penning, Carmen S. Fávaro-Trindade, Denis Poncelet

This study aimed to compare two processes for the encapsulation of Lactobacillus acidophilus LA3 using alginate or a blend of alginate–shellac as the wall material and sunflower oil as the core. The particles were dried and stored for up to 60 days at 25 °C for stability studies, and the survival of the encapsulated probiotics in simulated gastrointestinal fluids was evaluated. The viability of the LA3 encapsulated by co-extrusion using alginate or a blend of alginate–shellac was, respectively, 6.2 and 7.2 log CFU/g (colony-forming units per gram), after 60 days of storage, while the viability of the LA3 encapsulated by extrusion was, respectively, 5.3 and 6.2 log CFU/g. The particles produced with the blend of alginate–shellac presented additional protection to the probiotics, as revealed by the increased survival rates in simulated gastrointestinal fluids. Taken together, these data provide a promising alternative for the incorporation of the probiotic L. acidophilus LA3 into new functional foods.

6 UV-blocking properties of Zn/ZnO coatings on wood deposited by cold plasma spraying at atmospheric pressure 2017-11-16

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Publication date: 15 March 2018
Source:Applied Surface Science, Volume 434

Author(s): L. Wallenhorst, L. Gurău, A. Gellerich, H. Militz, G. Ohms, W. Viöl

In this study, artificial ageing of beech wood coated with Zn/ZnO particles by means of a cold plasma spraying process as well as coating systems including a Zn/ZnO layer and additional conventional sealings were examined. As ascertained by colour measurements, the particle coatings significantly decreased UV light-induced discolouration. Even though no significant colour changes were observed for particle-coated and alkyd-sealed samples, ATR-FTIR measurements revealed photocatalytic degradation of the alkyd matrix. In contrast, the polyurethane sealing appeared to be stabilised by the Zn/ZnO coating. Furthermore, morphologic properties of the pure particle coatings were studied by SEM and roughness measurements. SEM measurements confirmed a melting and solidifying process during deposition.

7 Morphological PLL for potential applications on renewable energy 2017-11-15

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Publication date: March 2018
Source:Electric Power Systems Research, Volume 156

Author(s): Carlos M. Rocha-Osorio, Juan S. Solís-Chaves, Saeed Golestan, Fabiano F. Costa, Darlan A. Fernandes, Josep M. Guerrero, Alfeu J. Sguarezi Filho

This paper proposes a new Phase Locked Loop (PLL) structure using a positive sequence component extraction based on Recursive Least Squares, altogether with a morphological filter and a fuzzy-tuned proportional-integral (PI) controller when the power quality conditions are degraded. A high detection accuracy in these conditions is achieved by means of the morphological filtering and the fuzzy-tuned PI controller. The performance of the novel PLL is appraised through a frequency variation, an asymmetrical voltage sag, and an odd harmonic distortion tests, with satisfactory simulated and experimental results which are compared with a Dual Second-Order Generalized Integrator – PLL (DSOGI-PLL).

8 Parameterized algorithms for recognizing monopolar and 2-subcolorable graphs 2017-11-14

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Publication date: March 2018
Source:Journal of Computer and System Sciences, Volume 92

Author(s): Iyad Kanj, Christian Komusiewicz, Manuel Sorge, Erik Jan van Leeuwen

A graph G is a $( Π A , Π B )$-graph if $V ( G )$ can be bipartitioned into A and B such that $G [ A ]$ satisfies property $Π A$ and $G [ B ]$ satisfies property $Π B$. The $( Π A , Π B )$ -Recognition problem is to recognize whether a given graph is a $( Π A , Π B )$-graph. There are many $( Π A , Π B )$-Recognition problems, including the recognition problems for bipartite, split, and unipolar graphs. We present efficient algorithms for many cases of $( Π A , Π B )$-Recognition based on a technique which we dub inductive recognition. In particular, we give fixed-parameter algorithms for two NP-hard $( Π A , Π B )$ -Recognition problems, Monopolar Recognition and 2-Subcoloring, parameterized by the number of maximal cliques in $G [ A ]$. We complement our algorithmic results with several hardness results for $( Π A , Π B )$ -Recognition.

9 Novel highly-integrated mems based solid state detectors for analytical gas chromatography 2017-11-14

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Publication date: March 2018
Source:Sensors and Actuators B: Chemical, Volume 256

Author(s): Alexander Larin, Phillip C. Womble, Vladimir Dobrokhotov

In this work, a novel detector of gaseous analytes for monitoring of low levels of BTEX (benzene, toluene, ethylbenzene and o-xylene) is discussed. The detector is based on SnO2 thin (30nm) films functionalized with gold-palladium (9:1 molar ratio) bimetal nanoparticles. The detector consists of four independent sensing elements thermally activated by an internal heater. The performance of Au/Pd@SnO2 sensing elements was evaluated in comparison with some other gas sensitive materials, such as: pure SnO2, SnO2 decorated with gold (Au), and SnO2 decorated with palladium (Pd) nanoparticles. The superiority of the gas sensing performance of the Au/Pd@SnO2 nanocomposite structure was demonstrated based on its response to low concentrations (12.5-500 ppb) of benzene or toluene. A more complex analysis of gaseous mixtures with different concentrations (0.3–20ppb) of BTEX mixture was accomplished by incorporating the novel detector into the portable gas chromatograph (GC) PAC R1120. High sensitivity of the detector in combination with fast response and recovery time allowed us to obtain fine gas chromatograms and to perform a complete analysis of a gas sample in less than 11min. Ultra-low concentrations of BTEX components at sub-ppb level (0.3 ppb) were identified and detected by the GC analysis. Besides the experimental data, the theoretical validation of the detector’s high performance was provided based on high catalytic activity of Au/Pd nanoparticles and electronic interaction of bimetal nanoclusters with SnO2 support.

10 Decoration of vertical graphene with tin dioxide nanoparticles for highly sensitive room temperature formaldehyde sensing 2017-11-14

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Publication date: March 2018
Source:Sensors and Actuators B: Chemical, Volume 256

Author(s): Zheng Bo, Mu Yuan, Shun Mao, Xia Chen, Jianhua Yan, Kefa Cen

A room temperature formaldehyde sensor with high sensitivity is fabricated using vertical graphene (VG) networks decorated with tin dioxide (SnO2) nanoparticles. VG was directly grown on the sensor electrodes using a microwave plasma-enhanced chemical vapor deposition (MW-PECVD) method. SnO2 nanoparticles were decorated on the VG side planes and edges sparsely and evenly with an electrochemical deposition method. The VG/SnO2 sensor exhibited high responses to low-concentration formaldehyde under room temperature. The low limit of detection (LOD) of VG/SnO2 sensor for formaldehyde sensing is 0.02ppm. The response time and recovery time were 46s and 95s for 5ppm formaldehyde, respectively. Moreover, the sensor showed excellent selectivity and stability. The mechanism responsible for good sensing performance was analyzed based on the special structure of VG and the synergistic effect between VG and the SnO2 nanoparticles.

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