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Open AccessArticle Versatility of Pyridoxal Phosphate as a Coating of Iron Oxide Nanoparticles

by Debora Bonvin, Ulrich J. Aschauer, Jessica A. M. Bastiaansen, Matthias Stuber, Heinrich Hofmann and Marijana Mionić Ebersold

Nanomaterials 2017, 7(8), 202; doi:10.3390/nano7080202 (registering DOI)

Received: 30 June 2017 / Revised: 21 July 2017 / Accepted: 26 July 2017 / Published: 29 July 2017

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Abstract

Pyridoxal 5′-phosphate (PLP) is the most important cofactor of vitamin B₆-dependent enzymes, which catalyses a wide range of essential body functions (e.g., metabolism) that could be exploited to specifically target highly metabolic cells, such as tumour metastatic cells. However, the use

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Pyridoxal 5′-phosphate (PLP) is the most important cofactor of vitamin B₆-dependent enzymes, which catalyses a wide range of essential body functions (e.g., metabolism) that could be exploited to specifically target highly metabolic cells, such as tumour metastatic cells. However, the use of PLP as a simultaneous coating and targeting molecule, which at once provides colloidal stability and specific biological effects has not been exploited so far. Therefore, in this work iron oxide nanoparticles (IONPs) were coated by PLP at two different pH values to tune PLP bonding (e.g., orientation) at the IONP surface. The surface study, as well as calculations, confirmed different PLP bonding to the IONP surface at these two pH values. Moreover, the obtained PLP-IONPs showed different zeta potential, hydrodynamic radius and agglomeration state, and consequently different uptake by two metastatic-prostate-cancer cell lines (LnCaP and PC3). In LnCaP cells, PLP modified the morphology of IONP-containing intracellular vesicles, while in PC3 cells PLP impacted the amount of IONPs taken up by cells. Moreover, PLP-IONPs displayed high magnetic resonance imaging (MRI) r₂ relaxivity and were not toxic for the two studied cell lines, rendering PLP promising for biomedical applications. We here report the use of PLP simultaneously as a coating and targeting molecule, directly bound to the IONP surface, with the additional high potential for MRI detection. Full article

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Open AccessArticle Rooftop Rainwater Harvesting for Mombasa: Scenario Development with Image Classification and Water Resources Simulation

by Robert O. Ojwang, Jörg Dietrich, Prajna Kasargodu Anebagilu, Matthias Beyer and Franz Rottensteiner

Water 2017, 9(5), 359; doi:10.3390/w9050359

Received: 28 February 2017 / Revised: 5 May 2017 / Accepted: 15 May 2017 / Published: 20 May 2017

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Abstract

Mombasa faces severe water scarcity problems. The existing supply is unable to satisfy the demand. This article demonstrates the combination of satellite image analysis and modelling as tools for the development of an urban rainwater harvesting policy. For developing a sustainable remedy policy,

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Mombasa faces severe water scarcity problems. The existing supply is unable to satisfy the demand. This article demonstrates the combination of satellite image analysis and modelling as tools for the development of an urban rainwater harvesting policy. For developing a sustainable remedy policy, rooftop rainwater harvesting (RRWH) strategies were implemented into the water supply and demand model WEAP (Water Evaluation and Planning System). Roof areas were detected using supervised image classification. Future population growth, improved living standards, and climate change predictions until 2035 were combined with four management strategies. Image classification techniques were able to detect roof areas with acceptable accuracy. The simulated annual yield of RRWH ranged from 2.3 to 23 million cubic meters (MCM) depending on the extent of the roof area. Apart from potential RRWH, additional sources of water are required for full demand coverage. Full article

(This article belongs to the Special Issue Rainwater Harvesting: Quantity, Quality, Economics and State Regulations)

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Open AccessArticle Glacier Changes in the Susitna Basin, Alaska, USA, (1951–2015) using GIS and Remote Sensing Methods

by Roland Wastlhuber, Regine Hock, Christian Kienholz and Matthias Braun

Remote Sens. 2017, 9(5), 478; doi:10.3390/rs9050478

Received: 18 March 2017 / Revised: 1 May 2017 / Accepted: 5 May 2017 / Published: 14 May 2017

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Abstract

The Susitna River draining from the highly glacierized Central Alaska Range has repeatedly been considered a potential hydro-power source in recent decades, raising questions about the effect of glacier changes on the basin’s river runoff. We determine changes in the glacier area (1951–2010),

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The Susitna River draining from the highly glacierized Central Alaska Range has repeatedly been considered a potential hydro-power source in recent decades, raising questions about the effect of glacier changes on the basin’s river runoff. We determine changes in the glacier area (1951–2010), elevation (1951–2010, 1951–2005 and 2005–2010), equilibrium line altitude (ELA, 1999–2015), and accumulation area ratio (AAR, 1999–2015) of the basin’s five largest glaciers covering 587 km² (2010). We use the Landsat time series, as well as digital elevation models (DEMs) from 1951 (United States Geological Survey (USGS) aerial imagery), 2005 (Advanced Spaceborne Thermal Emission and Reflection Radiometer, ASTER), and 2010 (airborne interferometric synthetic aperture radar, IfSAR). The glaciers lost an area of 128 ± 15 km² (16%) between 1951 and 2010. The mean ELA was located at 1745 ± 88 m a.s.l. during 1999–2015. The glacier’s annual ELAs do not show any significant trends. We found a glacier-wide elevation change of −0.41 ± 0.07 m yr⁻¹ for the period 1951–2005 and −1.20 ± 0.25 m yr⁻¹ for 2005–2010. The results indicate that the glaciers are in a state of retreat and thinning, and have been losing mass at an accelerated rate in recent years. The interpretation of the thickness changes is complicated by the glaciers’ surge cycles. Full article

(This article belongs to the Special Issue Remote Sensing of Glaciers)

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Open AccessArticle Toward Measuring Network Aesthetics Based on Symmetry

by Zengqiang Chen, Matthias Dehmer, Frank Emmert-Streib, Abbe Mowshowitz and Yongtang Shi

Axioms 2017, 6(2), 12; doi:10.3390/axioms6020012

Received: 20 March 2017 / Revised: 3 May 2017 / Accepted: 3 May 2017 / Published: 6 May 2017

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Abstract

In this exploratory paper, we discuss quantitative graph-theoretical measures of network aesthetics. Related work in this area has typically focused on geometrical features (e.g., line crossings or edge bendiness) of drawings or visual representations of graphs which purportedly affect an observer’s perception. Here

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In this exploratory paper, we discuss quantitative graph-theoretical measures of network aesthetics. Related work in this area has typically focused on geometrical features (e.g., line crossings or edge bendiness) of drawings or visual representations of graphs which purportedly affect an observer’s perception. Here we take a very different approach, abandoning reliance on geometrical properties, and apply information-theoretic measures to abstract graphs and networks directly (rather than to their visual representaions) as a means of capturing classical appreciation of structural symmetry. Examples are used solely to motivate the approach to measurement, and to elucidate our symmetry-based mathematical theory of network aesthetics. Full article

(This article belongs to the Special Issue Entropy and Information Theory)

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Open AccessReview Review of Life Cycle Sustainability Assessment and Potential for Its Adoption at an Automotive Company

by Peter Tarne, Marzia Traverso and Matthias Finkbeiner

Sustainability 2017, 9(4), 670; doi:10.3390/su9040670

Received: 22 December 2016 / Revised: 9 March 2017 / Accepted: 19 April 2017 / Published: 23 April 2017

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Abstract

The aim of this paper is to guide the next steps of a PhD thesis through a structured review of the state of the art and implementation of Life Cycle Sustainability Assessment (LCSA), and to identify challenges and potentials for its adoption at

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The aim of this paper is to guide the next steps of a PhD thesis through a structured review of the state of the art and implementation of Life Cycle Sustainability Assessment (LCSA), and to identify challenges and potentials for its adoption at an automotive company. First, the structured literature review was conducted on LCSA to screen the current methodological and practical implementations and to identify the main research needs in the field. Second, a research on the current status of LCSA within the automotive industry was carried out by means of investigation of published sources of 15 Original Equipment Manufacturers (OEM). By combining the results of both steps and consulting with decision makers, the challenges and potential for adopting LCSA at an automotive company were identified. The main challenges for adoption of LCSA were found to be: (1) the consistent execution of the three life cycle based assessment methods; (2) the comparatively low maturity of Social Life Cycle Assessment (S-LCA); and (3) the adequate presentation and interpretation of results. Next steps towards implementation would be a case study to gather experience on the combined execution of the three life cycle based assessments at an automotive company. Furthermore, it should be determined what the needs of decision makers at an automotive company are regarding the aggregation and interpretation of environmental, social, and economic impacts. Full article

(This article belongs to the Section Economic, Business and Management Aspects of Sustainability)

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Open AccessReview Therapeutic Potential of Targeting the Ghrelin Pathway

by Gustav Colldén, Matthias H. Tschöp and Timo D. Müller

Int. J. Mol. Sci. 2017, 18(4), 798; doi:10.3390/ijms18040798

Received: 28 February 2017 / Revised: 3 April 2017 / Accepted: 6 April 2017 / Published: 11 April 2017

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Abstract

Ghrelin was discovered in 1999 as the endogenous ligand of the growth-hormone secretagogue receptor 1a (GHSR1a). Since then, ghrelin has been found to exert a plethora of physiological effects that go far beyond its initial characterization as a growth hormone (GH) secretagogue. Among

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Ghrelin was discovered in 1999 as the endogenous ligand of the growth-hormone secretagogue receptor 1a (GHSR1a). Since then, ghrelin has been found to exert a plethora of physiological effects that go far beyond its initial characterization as a growth hormone (GH) secretagogue. Among the numerous well-established effects of ghrelin are the stimulation of appetite and lipid accumulation, the modulation of immunity and inflammation, the stimulation of gastric motility, the improvement of cardiac performance, the modulation of stress, anxiety, taste sensation and reward-seeking behavior, as well as the regulation of glucose metabolism and thermogenesis. Due to a variety of beneficial effects on systems’ metabolism, pharmacological targeting of the endogenous ghrelin system is widely considered a valuable approach to treat metabolic complications, such as chronic inflammation, gastroparesis or cancer-associated anorexia and cachexia. The aim of this review is to discuss and highlight the broad pharmacological potential of ghrelin pathway modulation for the treatment of anorexia, cachexia, sarcopenia, cardiopathy, neurodegenerative disorders, renal and pulmonary disease, gastrointestinal (GI) disorders, inflammatory disorders and metabolic syndrome. Full article

(This article belongs to the Special Issue Neurobiological Perspectives on Ghrelin)

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Open AccessArticle Assembly of One-Patch Colloids into Clusters via Emulsion Droplet Evaporation

by Hai Pham Van, Andrea Fortini and Matthias Schmidt

Materials 2017, 10(4), 361; doi:10.3390/ma10040361

Received: 23 February 2017 / Revised: 24 March 2017 / Accepted: 27 March 2017 / Published: 29 March 2017

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Abstract

We study the cluster structures of one-patch colloidal particles generated by droplet evaporation using Monte Carlo simulations. The addition of anisotropic patch–patch interaction between the colloids produces different cluster configurations. We find a well-defined category of sphere packing structures that minimize the second

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We study the cluster structures of one-patch colloidal particles generated by droplet evaporation using Monte Carlo simulations. The addition of anisotropic patch–patch interaction between the colloids produces different cluster configurations. We find a well-defined category of sphere packing structures that minimize the second moment of mass distribution when the attractive surface coverage of the colloids

χ

is larger than

0.3

. For

χ < 0.3

, the uniqueness of the packing structures is lost, and several different isomers are found. A further decrease of

χ

below

0.2

leads to formation of many isomeric structures with less dense packings. Our results could provide an explanation of the occurrence of uncommon cluster configurations in the literature observed experimentally through evaporation-driven assembly. Full article

(This article belongs to the Special Issue Designed Colloidal Self-Assembly)

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Open AccessFeature PaperTechnical Note Tensile Ductility of Nanostructured Bainitic Steels: Influence of Retained Austenite Stability

by Thomas Sourmail, Carlos Garcia-Mateo, Francisca G. Caballero, Lucia Morales-Rivas, Rosalia Rementeria and Matthias Kuntz

Metals 2017, 7(1), 31; doi:10.3390/met7010031

Received: 19 December 2016 / Revised: 9 January 2017 / Accepted: 16 January 2017 / Published: 23 January 2017

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Abstract

High silicon (>1.5%) steels with different compositions were isothermally transformed to bainite at 220 and 250 °C to produce what is often referred to as nanostructured bainite. Interrupted tensile tests were carried out and the retained austenite was measured as a function of

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High silicon (>1.5%) steels with different compositions were isothermally transformed to bainite at 220 and 250 °C to produce what is often referred to as nanostructured bainite. Interrupted tensile tests were carried out and the retained austenite was measured as a function of strain. Results were correlated with tensile ductility. The role of retained austenite stability is remarkably underlined as strongly affecting the propensity to brittle failure, but also the tensile ductility. A simple quantitative relationship is proposed that clearly delimitates the different behaviours (brittle/ductile) and correlates well with the measured ductility. Conclusions are proposed as to the role of retained austenite fraction and the existence of a threshold value associated with tensile rupture. Full article

(This article belongs to the Special Issue Bainite and Martensite: Developments and Challenges)

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Open AccessArticle A Fast Multimodal Ectopic Beat Detection Method Applied for Blood Pressure Estimation Based on Pulse Wave Velocity Measurements in Wearable Sensors

by Maik Pflugradt, Kai Geissdoerfer, Matthias Goernig and Reinhold Orglmeister

Sensors 2017, 17(1), 158; doi:10.3390/s17010158

Received: 9 November 2016 / Revised: 7 January 2017 / Accepted: 9 January 2017 / Published: 14 January 2017

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Abstract

Automatic detection of ectopic beats has become a thoroughly researched topic, with literature providing manifold proposals typically incorporating morphological analysis of the electrocardiogram (ECG). Although being well understood, its utilization is often neglected, especially in practical monitoring situations like online evaluation of signals

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Automatic detection of ectopic beats has become a thoroughly researched topic, with literature providing manifold proposals typically incorporating morphological analysis of the electrocardiogram (ECG). Although being well understood, its utilization is often neglected, especially in practical monitoring situations like online evaluation of signals acquired in wearable sensors. Continuous blood pressure estimation based on pulse wave velocity considerations is a prominent example, which depends on careful fiducial point extraction and is therefore seriously affected during periods of increased occurring extrasystoles. In the scope of this work, a novel ectopic beat discriminator with low computational complexity has been developed, which takes advantage of multimodal features derived from ECG and pulse wave relating measurements, thereby providing additional information on the underlying cardiac activity. Moreover, the blood pressure estimations’ vulnerability towards ectopic beats is closely examined on records drawn from the Physionet database as well as signals recorded in a small field study conducted in a geriatric facility for the elderly. It turns out that a reliable extrasystole identification is essential to unsupervised blood pressure estimation, having a significant impact on the overall accuracy. The proposed method further convinces by its applicability to battery driven hardware systems with limited processing power and is a favorable choice when access to multimodal signal features is given anyway. Full article

(This article belongs to the Special Issue Wearable Biomedical Sensors)

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Open AccessArticle Spatial Genetic Structure within and among Seed Stands of Pinus engelmannii Carr. and Pinus leiophylla Schiede ex Schltdl. & Cham, in Durango, Mexico

by María Elena Ortiz-Olivas, José Ciro Hernández-Díaz, Matthias Fladung, Álvaro Cañadas-López, José Ángel Prieto-Ruíz and Christian Wehenkel

Forests 2017, 8(1), 22; doi:10.3390/f8010022

Received: 27 October 2016 / Revised: 20 December 2016 / Accepted: 1 January 2017 / Published: 10 January 2017

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Abstract

Studies of spatial genetic structure (SGS) are important because they offer detailed insights into historical demographic and evolutionary processes and provide important information regarding species conservation and management. Pinus engelmannii and P. leiophylla var. leiophylla are two important timber tree species in Mexico,

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Studies of spatial genetic structure (SGS) are important because they offer detailed insights into historical demographic and evolutionary processes and provide important information regarding species conservation and management. Pinus engelmannii and P. leiophylla var. leiophylla are two important timber tree species in Mexico, covering about 2.5 and 1.9 million hectares, respectively. However, studies in relation to population genetics are unfortunately scant. The aim of this research was to use amplified fragment length polymorphisms (AFLP) analysis to identify potential differences in spatial genetic structure within and among seven Pinus engelmannii and nine P. leiophylla var. leiophylla seed stands in Durango, Mexico. Within the 16 seed stands of the two tested pine species, no significant SGS was detected, although SGS was detected among the seed stands. We concluded that the collection of seed in only some seed stands should not significantly alter the degree of genetic differentiation within the (collected) seed. Distances between seed orchards and pollen propagators of more than 24 km for P. engelmannii and 7 km for P. leiophylla may be sufficient to limit contamination. Finally, local seeds should be used for (re)forestation. Full article

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Open AccessReply Sometimes More is Too Much: A Rejoinder to the Commentaries on Greiff et al. (2015)

by Samuel Greiff, Matthias Stadler, Philipp Sonnleitner, Christian Wolff and Romain Martin

J. Intell. 2017, 5(1), 6; doi:10.3390/jintelligence5010006

Received: 5 December 2016 / Revised: 24 December 2016 / Accepted: 27 December 2016 / Published: 5 January 2017

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Abstract

In this rejoinder, we respond to two commentaries on the study by Greiff, S.; Stadler, M.; Sonnleitner, P.; Wolff, C.; Martin, R. Sometimes less is more: Comparing the validity of complex problem solving measures. Intelligence 2015, 50, 100–113. The study was

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In this rejoinder, we respond to two commentaries on the study by Greiff, S.; Stadler, M.; Sonnleitner, P.; Wolff, C.; Martin, R. Sometimes less is more: Comparing the validity of complex problem solving measures. Intelligence 2015, 50, 100–113. The study was the first to address the important comparison between a classical measure of complex problem solving (CPS) and the more recent multiple complex systems (MCS) approach regarding their validity. In the study, we investigated the relations between one classical microworld as the initially developed method (here, the Tailorshop) with three more recently developed multiple complex systems (MCS; here, MicroDYN, Genetics Lab, and MicroFIN) tests. We found that the MCS tests showed higher levels of convergent validity with each other than with the Tailorshop even after reasoning was controlled for, thus empirically distinguishing between the two approaches. The commentary by Kretzschmar and the commentary by Funke, Fischer, and Holt expressed several concerns with how our study was conducted, our data was analyzed, and our results were interpreted. Whereas we acknowledge and agree with some of the more general statements made in these commentaries, we respectfully disagree with others, or we consider them to be at least partially in contrast with the existing literature and the currently available empirical evidence. Full article

Open AccessReview Ductility of Nanostructured Bainite

by Lucia Morales-Rivas, Carlos Garcia-Mateo, Thomas Sourmail, Matthias Kuntz, Rosalia Rementeria and Francisca G. Caballero

Metals 2016, 6(12), 302; doi:10.3390/met6120302

Received: 25 October 2016 / Revised: 21 November 2016 / Accepted: 25 November 2016 / Published: 2 December 2016

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Abstract

Nanostructured bainite is a novel ultra-high-strength steel-concept under intensive current research, in which the optimization of its mechanical properties can only come from a clear understanding of the parameters that control its ductility. This work reviews first the nature of this composite-like material

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Nanostructured bainite is a novel ultra-high-strength steel-concept under intensive current research, in which the optimization of its mechanical properties can only come from a clear understanding of the parameters that control its ductility. This work reviews first the nature of this composite-like material as a product of heat treatment conditions. Subsequently, the premises of ductility behavior are presented, taking as a reference related microstructures: conventional bainitic steels, and TRIP-aided steels. The ductility of nanostructured bainite is then discussed in terms of work-hardening and fracture mechanisms, leading to an analysis of the three-fold correlation between ductility, mechanically-induced martensitic transformation, and mechanical partitioning between the phases. Results suggest that a highly stable/hard retained austenite, with mechanical properties close to the matrix of bainitic ferrite, is advantageous in order to enhance ductility. Full article

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Open AccessArticle Investigating Discontinuity of Age Relations in Cognitive Functioning, General Health Status, Activity Participation, and Life Satisfaction between Young-Old and Old-Old Age

by Andreas Ihle, Daniela S. Jopp, Michel Oris, Delphine Fagot and Matthias Kliegel

Int. J. Environ. Res. Public Health 2016, 13(11), 1092; doi:10.3390/ijerph13111092

Received: 22 September 2016 / Revised: 27 October 2016 / Accepted: 3 November 2016 / Published: 5 November 2016

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Abstract

Health research suggests that findings on young-old adults cannot be generalized to old-old adults and thus that old-old age seems not a simple continuation of young-old age due to qualitative changes that result in a discontinuity in old age. Specifically, it would be

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Health research suggests that findings on young-old adults cannot be generalized to old-old adults and thus that old-old age seems not a simple continuation of young-old age due to qualitative changes that result in a discontinuity in old age. Specifically, it would be of conceptual and methodological importance to inform research regarding estimates around which chronological age the beginning of old-old age could be placed at a population level, and whether this is universal or domain-specific. To derive such criteria, we investigated potential discontinuity of age relations between young-old and old-old age in a large population-based sample considering measures in different domains (processing speed, verbal abilities, general health status, activity participation, and life satisfaction). For processing speed, verbal abilities, general health status, and life satisfaction we observed some very small indication that there might be a discontinuity of age relations at the end of individuals’ eighties, and for activity participation already at the beginning of individuals’ eighties. In conclusion, models conceptualizing aging as a gradual development might not suffice to adequately represent the differences between the stages of young-old and old-old age due to some very small indication that there might be discontinuity in late adulthood. Full article

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Open AccessArticle Millimeter VLBI of NGC 1052: Dynamics

by Anne-Kathrin Baczko, Robert Schulz, Eduardo Ros, Matthias Kadler, Manel Perucho and Jörn Wilms

Galaxies 2016, 4(4), 48; doi:10.3390/galaxies4040048

Received: 15 July 2016 / Revised: 30 September 2016 / Accepted: 9 October 2016 / Published: 20 October 2016

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Abstract

The LINER galaxy NGC 1052 is an ideal target to study the innermost regions of active galactic nuclei (AGN), given its close distance of about 20 Mpc. The source was observed at 29 epochs from 2005 to 2009 with the Very Long Baseline

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The LINER galaxy NGC 1052 is an ideal target to study the innermost regions of active galactic nuclei (AGN), given its close distance of about 20 Mpc. The source was observed at 29 epochs from 2005 to 2009 with the Very Long Baseline Array (VLBA) at 43 GHz. Here, we present a kinematic study of its twin-jet system from a subset of 9 epochs at 43 GHz carried out in 2005 and 2006, finding a bright central feature as the dynamic center. The resulting mean velocities of

β = v / c = 0.46 \pm 0.08

and

β = 0.69 \pm 0.02

for the western and eastern jet, respectively, give hints towards higher velocities in the eastern jet. Full article

(This article belongs to the Special Issue Blazars through Sharp Multi-wavelength Eyes)

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Open AccessArticle Wing Tip Drag Reduction at Nominal Take-Off Mach Number: An Approach to Local Active Flow Control with a Highly Robust Actuator System

by Matthias Bauer, Thomas Grund, Wolfgang Nitsche and Vlad Ciobaca

Aerospace 2016, 3(4), 36; doi:10.3390/aerospace3040036

Received: 19 July 2016 / Revised: 8 October 2016 / Accepted: 9 October 2016 / Published: 19 October 2016

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Abstract

This paper discusses wind tunnel test results aimed at advancing active flow control technology to increase the aerodynamic efficiency of an aircraft during take-off. A model of the outer section of a representative civil airliner wing was equipped with two-stage fluidic actuators between

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This paper discusses wind tunnel test results aimed at advancing active flow control technology to increase the aerodynamic efficiency of an aircraft during take-off. A model of the outer section of a representative civil airliner wing was equipped with two-stage fluidic actuators between the slat edge and wing tip, where mechanical high-lift devices fail to integrate. The experiments were conducted at a nominal take-off Mach number of M = 0.2. At this incidence velocity, separation on the wing section, accompanied by increased drag, is triggered by the strong slat edge vortex at high angles of attack. On the basis of global force measurements and local static pressure data, the effect of pulsed blowing on the complex flow is evaluated, considering various momentum coefficients and spanwise distributions of the actuation effort. It is shown that through local intensification of forcing, a momentum coefficient of less than

c_{μ} = 0.6 %

suffices to offset the stall by 2.4°, increase the maximum lift by more than 10% and reduce the drag by 37% compared to the uncontrolled flow. Full article

(This article belongs to the Special Issue State-of-the-Art Aerospace Sciences and Technologies in Europe)

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Open AccessArticle A Constitutive Relationship between Fatigue Limit and Microstructure in Nanostructured Bainitic Steels

by Inga Mueller, Rosalia Rementeria, Francisca G. Caballero, Matthias Kuntz, Thomas Sourmail and Eberhard Kerscher

Materials 2016, 9(10), 831; doi:10.3390/ma9100831

Received: 31 August 2016 / Revised: 21 September 2016 / Accepted: 27 September 2016 / Published: 14 October 2016

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Abstract

The recently developed nanobainitic steels show high strength as well as high ductility. Although this combination seems to be promising for fatigue design, fatigue properties of nanostructured bainitic steels are often surprisingly low. To improve the fatigue behavior, an understanding of the correlation

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The recently developed nanobainitic steels show high strength as well as high ductility. Although this combination seems to be promising for fatigue design, fatigue properties of nanostructured bainitic steels are often surprisingly low. To improve the fatigue behavior, an understanding of the correlation between the nanobainitic microstructure and the fatigue limit is fundamental. Therefore, our hypothesis to predict the fatigue limit was that the main function of the microstructure is not necessarily totally avoiding the initiation of a fatigue crack, but the microstructure has to increase the ability to decelerate or to stop a growing fatigue crack. Thus, the key to understanding the fatigue behavior of nanostructured bainite is to understand the role of the microstructural features that could act as barriers for growing fatigue cracks. To prove this hypothesis, we carried out fatigue tests, crack growth experiments, and correlated these results to the size of microstructural features gained from microstructural analysis by light optical microscope and EBSD-measurements. Finally, we were able to identify microstructural features that influence the fatigue crack growth and the fatigue limit of nanostructured bainitic steels. Full article

(This article belongs to the Special Issue Fracture and Fatigue Mechanics of Materials)

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Open AccessReview Controlled Synthesis of Polyions of Heavy Main-Group Elements in Ionic Liquids

by Matthias F. Groh, Alexander Wolff, Matthias A. Grasser and Michael Ruck

Int. J. Mol. Sci. 2016, 17(9), 1452; doi:10.3390/ijms17091452

Received: 5 July 2016 / Revised: 19 August 2016 / Accepted: 23 August 2016 / Published: 1 September 2016

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Abstract

Ionic liquids (ILs) have been proven to be valuable reaction media for the synthesis of inorganic materials among an abundance of other applications in different fields of chemistry. Up to now, the syntheses have remained mostly “black boxes”; and researchers have to resort

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Ionic liquids (ILs) have been proven to be valuable reaction media for the synthesis of inorganic materials among an abundance of other applications in different fields of chemistry. Up to now, the syntheses have remained mostly “black boxes”; and researchers have to resort to trial-and-error in order to establish a new synthetic route to a specific compound. This review comprises decisive reaction parameters and techniques for the directed synthesis of polyions of heavy main-group elements (fourth period and beyond) in ILs. Several families of compounds are presented ranging from polyhalides over carbonyl complexes and selenidostannates to homo and heteropolycations. Full article

(This article belongs to the Special Issue Ionic Liquids 2016 and Selected Papers from ILMAT III)

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Open AccessArticle Three-Dimensional Body and Centre of Mass Kinematics in Alpine Ski Racing Using Differential GNSS and Inertial Sensors

by Benedikt Fasel, Jörg Spörri, Matthias Gilgien, Geo Boffi, Julien Chardonnens, Erich Müller and Kamiar Aminian

Remote Sens. 2016, 8(8), 671; doi:10.3390/rs8080671

Received: 30 June 2016 / Revised: 2 August 2016 / Accepted: 16 August 2016 / Published: 22 August 2016

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Abstract

A key point in human movement analysis is measuring the trajectory of a person’s center of mass (CoM). For outdoor applications, differential Global Navigation Satellite Systems (GNSS) can be used for tracking persons since they allow measuring the trajectory and speed of the

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A key point in human movement analysis is measuring the trajectory of a person’s center of mass (CoM). For outdoor applications, differential Global Navigation Satellite Systems (GNSS) can be used for tracking persons since they allow measuring the trajectory and speed of the GNSS antenna with centimeter accuracy. However, the antenna cannot be placed exactly at the person’s CoM, but rather on the head or upper back. Thus, a model is needed to relate the measured antenna trajectory to the CoM trajectory. In this paper we propose to estimate the person’s posture based on measurements obtained from inertial sensors. From this estimated posture the CoM is computed relative to the antenna position and finally fused with the GNSS trajectory information to obtain the absolute CoM trajectory. In a biomechanical field experiment, the method has been applied to alpine ski racing and validated against a camera-based stereo photogrammetric system. CoM position accuracy and precision was found to be 0.08 m and 0.04 m, respectively. CoM speed accuracy and precision was 0.04 m/s and 0.14 m/s, respectively. The observed accuracy and precision might be sufficient for measuring performance- or equipment-related trajectory differences in alpine ski racing. Moreover, the CoM estimation was not based on a movement-specific model and could be used for other skiing disciplines or sports as well. Full article

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Open AccessArticle The Sulphur Poisoning Behaviour of Gadolinia Doped Ceria Model Systems in Reducing Atmospheres

by Matthias Gerstl, Andreas Nenning, Riza Iskandar, Veronika Rojek-Wöckner, Martin Bram, Herbert Hutter and Alexander Karl Opitz

Materials 2016, 9(8), 649; doi:10.3390/ma9080649

Received: 10 June 2016 / Revised: 7 July 2016 / Accepted: 12 July 2016 / Published: 2 August 2016

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Abstract

An array of analytical methods including surface area determination by gas adsorption using the Brunauer, Emmett, Teller (BET) method, combustion analysis, XRD, ToF-SIMS, TEM and impedance spectroscopy has been used to investigate the interaction of gadolinia doped ceria (GDC) with hydrogen sulphide containing

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An array of analytical methods including surface area determination by gas adsorption using the Brunauer, Emmett, Teller (BET) method, combustion analysis, XRD, ToF-SIMS, TEM and impedance spectroscopy has been used to investigate the interaction of gadolinia doped ceria (GDC) with hydrogen sulphide containing reducing atmospheres. It is shown that sulphur is incorporated into the GDC bulk and might lead to phase changes. Additionally, high concentrations of silicon are found on the surface of model composite microelectrodes. Based on these data, a model is proposed to explain the multi-facetted electrochemical degradation behaviour encountered during long term electrochemical measurements. While electrochemical bulk properties of GDC stay largely unaffected, the surface polarisation resistance is dramatically changed, due to silicon segregation and reaction with adsorbed sulphur. Full article

(This article belongs to the Special Issue Recent Advances in Materials for Solid Oxide Cells)

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Open AccessArticle The RADAR Project—A Service for Research Data Archival and Publication

by Angelina Kraft, Matthias Razum, Jan Potthoff, Andrea Porzel, Thomas Engel, Frank Lange, Karina van den Broek and Filipe Furtado

ISPRS Int. J. Geo-Inf. 2016, 5(3), 28; doi:10.3390/ijgi5030028

Received: 26 November 2015 / Revised: 20 January 2016 / Accepted: 17 February 2016 / Published: 4 March 2016

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Abstract

The aim of the RADAR (Research Data Repository) project is to set up and establish an infrastructure that facilitates research data management: the infrastructure will allow researchers to store, manage, annotate, cite, curate, search and find scientific data in a digital platform available

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The aim of the RADAR (Research Data Repository) project is to set up and establish an infrastructure that facilitates research data management: the infrastructure will allow researchers to store, manage, annotate, cite, curate, search and find scientific data in a digital platform available at any time that can be used by multiple (specialized) disciplines. While appropriate and innovative preservation strategies and systems are in place for the big data communities (e.g., environmental sciences, space, and climate), the stewardship for many other disciplines, often called the “long tail research domains”, is uncertain. Funded by the German Research Foundation (DFG), the RADAR collaboration project develops a service oriented infrastructure for the preservation, publication and traceability of (independent) research data. The key aspect of RADAR is the implementation of a two-stage business model for data preservation and publication: clients may preserve research results for up to 15 years and assign well-graded access rights, or to publish data with a DOI assignment for an unlimited period of time. Potential clients include libraries, research institutions, publishers and open platforms that desire an adaptable digital infrastructure to archive and publish data according to their institutional requirements and workflows. Full article

(This article belongs to the Special Issue Research Data Management)

Open AccessArticle The Effect of Land Use on Availability of Japanese Freshwater Resources and Its Significance for Water Footprinting

by Masaharu Motoshita, Yuya Ono, Matthias Finkbeiner and Atsushi Inaba

Sustainability 2016, 8(1), 86; doi:10.3390/su8010086

Received: 19 October 2015 / Revised: 14 December 2015 / Accepted: 12 January 2016 / Published: 16 January 2016

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Abstract

All relevant effects on water must be assessed in water footprinting for identifying hotspots and managing the impacts of products, processes, and services throughout the life cycle. Although several studies have focused on physical water scarcity and degradation of water quality, the relevance

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All relevant effects on water must be assessed in water footprinting for identifying hotspots and managing the impacts of products, processes, and services throughout the life cycle. Although several studies have focused on physical water scarcity and degradation of water quality, the relevance of land use in water footprinting has not been widely addressed. Here, we aimed to verify the extent of land-use effect in the context of water footprinting. Intensity factors of land use regarding the loss of freshwater availability are modeled by calculating water balance at grid scale in Japan. A water footprint inventory and impacts related to land use are assessed by applying the developed intensity factors and comparing them with those related to water consumption and degradation. Artificial land use such as urban area results in the loss of many parts of available freshwater input by precipitation. When considering water footprint inventory, the dominance of land use is less than that of water consumption. However, the effect of land use is relevant to the assessment of water footprint impact by differentiating stress on water resources. The exclusion of land use effect underestimates the water footprint of goods produced in Japan by an average of around 37%. Full article

(This article belongs to the Special Issue Creating Benefits through Life Cycle Thinking: Practices and Challenges from EcoBalance)

Open AccessArticle Narrow Bandwidth Top-Emitting OLEDs Designed for Rhodamine 6G Excitation in Biological Sensing Applications

by Matthias Jahnel, Beatrice Beyer, Michael Thomschke, Karsten Fehse, Felix Krujatz and Karl Leo

Electronics 2015, 4(4), 982-994; doi:10.3390/electronics4040982

Received: 2 September 2015 / Revised: 5 November 2015 / Accepted: 10 November 2015 / Published: 25 November 2015

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Abstract

Organic light emitting diodes (OLED) are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen

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Organic light emitting diodes (OLED) are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen (O₂) species in bio reactors or excitation of fluorescent markers. In this work, we investigate different OLED devices for biomedical applications to excite the fluorescent dye rhodamine 6G (R6G). The OLED devices are built in top emission geometry comprising a distributed Bragg reflector (DBR) acting as optical mirror. The OLED is optimized to provide a very narrow emission characteristic to excite the R6G at 530 nm wavelength and enabling the possibility to minimize the optical crosstalk between the OLED electroluminescence and the fluorescence of R6G. The DBR includes a thin film encapsulation and enables the narrowing of the spectral emission band depending on the number of DBR pairs. The comparison between optical simulation data and experimental results exhibits good agreement and proves process stability. Full article

(This article belongs to the Special Issue Organic Materials and Sensors for Biomedical Applications)

Open AccessArticle Characterization of Complex Fractionated Atrial Electrograms by Sample Entropy: An International Multi-Center Study

by Eva Cirugeda–Roldán, Daniel Novak, Vaclav Kremen, David Cuesta–Frau, Matthias Keller, Armin Luik and Martina Srutova

Entropy 2015, 17(11), 7493-7509; doi:10.3390/e17117493

Received: 11 September 2015 / Revised: 21 October 2015 / Accepted: 22 October 2015 / Published: 28 October 2015

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Abstract

Atrial fibrillation (AF) is the most commonly clinically-encountered arrhythmia. Catheter ablation of AF is mainly based on trigger elimination and modification of the AF substrate. Substrate mapping ablation of complex fractionated atrial electrograms (CFAEs) has emerged to be a promising technique. To improve

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Atrial fibrillation (AF) is the most commonly clinically-encountered arrhythmia. Catheter ablation of AF is mainly based on trigger elimination and modification of the AF substrate. Substrate mapping ablation of complex fractionated atrial electrograms (CFAEs) has emerged to be a promising technique. To improve substrate mapping based on CFAE analysis, automatic detection algorithms need to be developed in order to simplify and accelerate the ablation procedures. According to the latest studies, the level of fractionation has been shown to be promisingly well estimated from CFAE measured during radio frequency (RF) ablation of AF. The nature of CFAE is generally nonlinear and nonstationary, so the use of complexity measures is considered to be the appropriate technique for the analysis of AF records. This work proposes the use of sample entropy (SampEn), not only as a way to discern between non-fractionated and fractionated atrial electrograms (A-EGM), Entropy 2015, 17 7494 but also as a tool for characterizing the degree of A-EGM regularity, which is linked to changes in the AF substrate and to heart tissue damage. The use of SampEn combined with a blind parameter estimation optimization process enables the classification between CFAE and non-CFAE with statistical significance (p < 0:001), 0.89 area under the ROC, 86% specificity and 77% sensitivity over a mixed database of A-EGM combined from two independent CFAE signal databases, recorded during RF ablation of AF in two EU countries (542 signals in total). On the basis of the results obtained in this study, it can be suggested that the use of SampEn is suitable for real-time support during navigation of RF ablation of AF, as only 1.5 seconds of signal segments need to be analyzed. Full article

(This article belongs to the Special Issue Complex and Fractional Dynamics)

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Open AccessReview Neuroscience of Internet Pornography Addiction: A Review and Update

by Todd Love, Christian Laier, Matthias Brand, Linda Hatch and Raju Hajela

Behav. Sci. 2015, 5(3), 388-433; doi:10.3390/bs5030388

Received: 2 July 2015 / Revised: 29 August 2015 / Accepted: 8 September 2015 / Published: 18 September 2015

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Abstract

Many recognize that several behaviors potentially affecting the reward circuitry in human brains lead to a loss of control and other symptoms of addiction in at least some individuals. Regarding Internet addiction, neuroscientific research supports the assumption that underlying neural processes are similar

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Many recognize that several behaviors potentially affecting the reward circuitry in human brains lead to a loss of control and other symptoms of addiction in at least some individuals. Regarding Internet addiction, neuroscientific research supports the assumption that underlying neural processes are similar to substance addiction. The American Psychiatric Association (APA) has recognized one such Internet related behavior, Internet gaming, as a potential addictive disorder warranting further study, in the 2013 revision of their Diagnostic and Statistical Manual. Other Internet related behaviors, e.g., Internet pornography use, were not covered. Within this review, we give a summary of the concepts proposed underlying addiction and give an overview about neuroscientific studies on Internet addiction and Internet gaming disorder. Moreover, we reviewed available neuroscientific literature on Internet pornography addiction and connect the results to the addiction model. The review leads to the conclusion that Internet pornography addiction fits into the addiction framework and shares similar basic mechanisms with substance addiction. Together with studies on Internet addiction and Internet Gaming Disorder we see strong evidence for considering addictive Internet behaviors as behavioral addiction. Future research needs to address whether or not there are specific differences between substance and behavioral addiction. Full article

(This article belongs to the Special Issue Addictive Behaviors: Assessment and Treatment)

Open AccessReview Fire Blight Control: The Struggle Goes On. A Comparison of Different Fire Blight Control Methods in Switzerland with Respect to Biosafety, Efficacy and Durability

by Michele Gusberti, Urs Klemm, Matthias S. Meier, Monika Maurhofer and Isabel Hunger-Glaser

Int. J. Environ. Res. Public Health 2015, 12(9), 11422-11447; doi:10.3390/ijerph120911422

Received: 8 July 2015 / Revised: 27 August 2015 / Accepted: 1 September 2015 / Published: 11 September 2015

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Abstract

Fire blight (FB), caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable

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Fire blight (FB), caused by Erwinia amylovora, is one of the most important pome fruit pathogens worldwide. To control this devastating disease, various chemical and biological treatments are commonly applied in Switzerland, but they fail to keep the infection at an acceptable level in years of heavy disease pressure. The Swiss authorities therefore currently allow the controlled use of the antibiotic streptomycin against FB in years that are predicted to have heavy infection periods, but only one treatment per season is permitted. Another strategy for controlling Erwinia is to breed resistant/tolerant apple cultivars. One way of accelerating the breeding process is to obtain resistant cultivars by inserting one or several major resistance genes, using genetic engineering. To date, no study summarizing the impact of different FB control measures on the environment and on human health has been performed. This study consequently aims to compare different disease-control measures (biological control, chemical control, control by antibiotics and by resistant/tolerant apple cultivars obtained through conventional or molecular breeding) applied against E. amylovora, considering different protection goals (protection of human health, environment, agricultural diversity and economic interest), with special emphasis on biosafety aspects. Information on each FB control measure in relation to the specified protection goal was assessed by literature searches and by interviews with experts. Based on our results it can be concluded that the FB control measures currently applied in Switzerland are safe for consumers, workers and the environment. However, there are several gaps in our knowledge of the human health and environmental impacts analyzed: data are missing (1) on long term studies on the efficacy of most of the analyzed FB control measures; (2) on the safety of operators handling streptomycin; (3) on residue analyses of Equisetum plant extract, the copper and aluminum compounds used in apple production; and (4) on the effect of biological and chemical control measures on non-target fauna and flora. These gaps urgently need to be addressed in the near future. Full article

Open AccessArticle Movement Pattern Analysis Based on Sequence Signatures

by Seyed Hossein Chavoshi, Bernard De Baets, Tijs Neutens, Matthias Delafontaine, Guy De Tré and Nico Van de Weghe

ISPRS Int. J. Geo-Inf. 2015, 4(3), 1605-1626; doi:10.3390/ijgi4031605

Received: 13 July 2015 / Revised: 3 August 2015 / Accepted: 27 August 2015 / Published: 2 September 2015

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Abstract

Increased affordability and deployment of advanced tracking technologies have led researchers from various domains to analyze the resulting spatio-temporal movement data sets for the purpose of knowledge discovery. Two different approaches can be considered in the analysis of moving objects: quantitative analysis and

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Increased affordability and deployment of advanced tracking technologies have led researchers from various domains to analyze the resulting spatio-temporal movement data sets for the purpose of knowledge discovery. Two different approaches can be considered in the analysis of moving objects: quantitative analysis and qualitative analysis. This research focuses on the latter and uses the qualitative trajectory calculus (QTC), a type of calculus that represents qualitative data on moving point objects (MPOs), and establishes a framework to analyze the relative movement of multiple MPOs. A visualization technique called sequence signature (SESI) is used, which enables to map QTC patterns in a 2D indexed rasterized space in order to evaluate the similarity of relative movement patterns of multiple MPOs. The applicability of the proposed methodology is illustrated by means of two practical examples of interacting MPOs: cars on a highway and body parts of a samba dancer. The results show that the proposed method can be effectively used to analyze interactions of multiple MPOs in different domains. Full article

(This article belongs to the Special Issue Multi-Dimensional Spatial Data Modeling)

Open AccessArticle A Single Nucleotide Polymorphism near the CYP17A1 Gene Is Associated with Left Ventricular Mass in Hypertensive Patients under Pharmacotherapy

by Matthias Huber, Susanne Lezius, Rona Reibis, Andras Treszl, Dorota Kujawinska, Stefanie Jakob, Karl Wegscheider, Heinz Völler and Reinhold Kreutz

Int. J. Mol. Sci. 2015, 16(8), 17456-17468; doi:10.3390/ijms160817456

Received: 29 June 2015 / Revised: 16 July 2015 / Accepted: 23 July 2015 / Published: 30 July 2015

Abstract

Cytochrome P450 17A1 (CYP17A1) catalyses the formation and metabolism of steroid hormones. They are involved in blood pressure (BP) regulation and in the pathogenesis of left ventricular hypertrophy. Therefore, altered function of CYP17A1 due to genetic variants may influence BP and left ventricular

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Cytochrome P450 17A1 (CYP17A1) catalyses the formation and metabolism of steroid hormones. They are involved in blood pressure (BP) regulation and in the pathogenesis of left ventricular hypertrophy. Therefore, altered function of CYP17A1 due to genetic variants may influence BP and left ventricular mass. Notably, genome wide association studies supported the role of this enzyme in BP control. Against this background, we investigated associations between single nucleotide polymorphisms (SNPs) in or nearby the CYP17A1 gene with BP and left ventricular mass in patients with arterial hypertension and associated cardiovascular organ damage treated according to guidelines. Patients (n = 1007, mean age 58.0 ± 9.8 years, 83% men) with arterial hypertension and cardiac left ventricular ejection fraction (LVEF) ≥40% were enrolled in the study. Cardiac parameters of left ventricular mass, geometry and function were determined by echocardiography. The cohort comprised patients with coronary heart disease (n = 823; 81.7%) and myocardial infarction (n = 545; 54.1%) with a mean LVEF of 59.9% ± 9.3%. The mean left ventricular mass index (LVMI) was 52.1 ± 21.2 g/m^2.7 and 485 (48.2%) patients had left ventricular hypertrophy. There was no significant association of any investigated SNP (rs619824, rs743572, rs1004467, rs11191548, rs17115100) with mean 24 h systolic or diastolic BP. However, carriers of the rs11191548 C allele demonstrated a 7% increase in LVMI (95% CI: 1%–12%, p = 0.017) compared to non-carriers. The CYP17A1 polymorphism rs11191548 demonstrated a significant association with LVMI in patients with arterial hypertension and preserved LVEF. Thus, CYP17A1 may contribute to cardiac hypertrophy in this clinical condition. Full article

(This article belongs to the collection Human Single Nucleotide Polymorphisms and Disease Diagnostics)

Open AccessArticle Phylogeny of the Vitamin K 2,3-Epoxide Reductase (VKOR) Family and Evolutionary Relationship to the Disulfide Bond Formation Protein B (DsbB) Family

by Carville G. Bevans, Christoph Krettler, Christoph Reinhart, Matthias Watzka and Johannes Oldenburg

Nutrients 2015, 7(8), 6224-6249; doi:10.3390/nu7085281

Received: 18 May 2015 / Revised: 25 June 2015 / Accepted: 9 July 2015 / Published: 29 July 2015

Abstract

In humans and other vertebrate animals, vitamin K 2,3-epoxide reductase (VKOR) family enzymes are the gatekeepers between nutritionally acquired K vitamins and the vitamin K cycle responsible for posttranslational modifications that confer biological activity upon vitamin K-dependent proteins with crucial roles in hemostasis,

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In humans and other vertebrate animals, vitamin K 2,3-epoxide reductase (VKOR) family enzymes are the gatekeepers between nutritionally acquired K vitamins and the vitamin K cycle responsible for posttranslational modifications that confer biological activity upon vitamin K-dependent proteins with crucial roles in hemostasis, bone development and homeostasis, hormonal carbohydrate regulation and fertility. We report a phylogenetic analysis of the VKOR family that identifies five major clades. Combined phylogenetic and site-specific conservation analyses point to clade-specific similarities and differences in structure and function. We discovered a single-site determinant uniquely identifying VKOR homologs belonging to human pathogenic, obligate intracellular prokaryotes and protists. Building on previous work by Sevier et al. (Protein Science 14:1630), we analyzed structural data from both VKOR and prokaryotic disulfide bond formation protein B (DsbB) families and hypothesize an ancient evolutionary relationship between the two families where one family arose from the other through a gene duplication/deletion event. This has resulted in circular permutation of primary sequence threading through the four-helical bundle protein folds of both families. This is the first report of circular permutation relating distant a-helical membrane protein sequences and folds. In conclusion, we suggest a chronology for the evolution of the five extant VKOR clades. Full article

(This article belongs to the Special Issue Vitamin K and Vitamin K-Dependent Proteins in Relation to Human Health)

Open AccessArticle Entropy of Weighted Graphs with Randi´c Weights

by Zengqiang Chen, Matthias Dehmer, Frank Emmert-Streib and Yongtang Shi

Entropy 2015, 17(6), 3710-3723; doi:10.3390/e17063710

Received: 18 May 2015 / Revised: 29 May 2015 / Accepted: 1 June 2015 / Published: 5 June 2015

Cited by 11 | Viewed by 1114 | PDF Full-text (326 KB) | HTML Full-text | XML Full-text

Abstract

Shannon entropies for networks have been widely introduced. However, entropies for weighted graphs have been little investigated. Inspired by the work due to Eagle et al., we introduce the concept of graph entropy for special weighted graphs. Furthermore, we prove extremal properties by

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Shannon entropies for networks have been widely introduced. However, entropies for weighted graphs have been little investigated. Inspired by the work due to Eagle et al., we introduce the concept of graph entropy for special weighted graphs. Furthermore, we prove extremal properties by using elementary methods of classes of weighted graphs, and in particular, the one due to Bollobás and Erdös, which is also called the Randi´c weight. As a result, we derived statements on dendrimers that have been proven useful for applications. Finally, some open problems are presented. Full article

Open AccessArticle Towards a More Sustainable Building Stock: Optimizing a Flemish Dwelling Using a Life Cycle Approach

by Matthias Buyle, Amaryllis Audenaert, Johan Braet and Wim Debacker

Buildings 2015, 5(2), 424-448; doi:10.3390/buildings5020424

Received: 27 February 2015 / Revised: 28 April 2015 / Accepted: 29 April 2015 / Published: 11 May 2015

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Abstract

Over the past decades, the construction sector has focused strongly on reducing operational energy consumption. Other types of environmental impact that occur during the life span of construction works, however, have to be taken into account as well. This case study focuses on

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Over the past decades, the construction sector has focused strongly on reducing operational energy consumption. Other types of environmental impact that occur during the life span of construction works, however, have to be taken into account as well. This case study focuses on developing scenarios to improve the environmental profile of new buildings in the Flemish/Belgian context. The study takes into account current energy regulation and investigates the influence of energy scenarios and building type on the environmental profile. A life cycle energy assessment (LCEA) and a life cycle impact assessment (LCIA) were carried out for all scenarios, supplemented by a screening life cycle costing (LCC). The results indicate the importance of the compactness of a building, with the best results identified for the terraced scenario. The results are due to the reduced use of materials and, to a smaller extent, a reduction in energy consumption (smaller exposed surface). The results of the energy scenarios show a discrepancy between the LCEA and LCIA. According to the LCEA, passive scenarios are always preferable, but the LCIA results suggest two ways to reach a similar environmental profile. Firstly, by providing a level of insulation based on current regulations complemented with advanced technical services, and, alternatively, by increasing the level of insulation along with standard services. The results of the LCC show a similar trend to those of the LCIA. The results therefore suggest that there are multiple ways to improve the environmental profile of new buildings. Nevertheless, the choice of impact assessment method can have a strong influence on the results. Full article

(This article belongs to the Special Issue Life-Cycle Energy Analysis of Buildings)

Open AccessArticle The Hosoya Entropy of a Graph

by Abbe Mowshowitz and Matthias Dehmer

Entropy 2015, 17(3), 1054-1062; doi:10.3390/e17031054

Received: 10 February 2015 / Revised: 2 March 2015 / Accepted: 2 March 2015 / Published: 5 March 2015

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Abstract

This paper demonstrates properties of Hosoya entropy, a quantitative measure of graph complexity based on a decomposition of the vertices linked to partial Hosoya polynomials. Connections between the information content of a graph and Hosoya entropy are established, and the special case of

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This paper demonstrates properties of Hosoya entropy, a quantitative measure of graph complexity based on a decomposition of the vertices linked to partial Hosoya polynomials. Connections between the information content of a graph and Hosoya entropy are established, and the special case of Hosoya entropy of trees is investigated. Full article

(This article belongs to the Section Complexity)

Open AccessArticle Screening of Panamanian Plant Extracts for Pesticidal Properties and HPLC-Based Identification of Active Compounds

by Niels GULDBRANDSEN, Maria DE MIERI, Mahabir GUPTA, Tobias SEISER, Christine WIEBE, Joachim DICKHAUT, Rüdiger REINGRUBER, Oliver SORGENFREI and Matthias HAMBURGER

Sci. Pharm. 2015, 83(2), 353-367; doi:10.3797/scipharm.1410-10

Received: 17 October 2014 / Accepted: 11 December 2014 / Published: 11 December 2014

Viewed by 179 | PDF Full-text (676 KB) | Supplementary Files

Abstract

A library of 600 taxonomically diverse Panamanian plant extracts was screened for fungicidal, insecticidal, and herbicidal activities. A total of 19 active extracts were submitted to HPLC-based activity profiling, and extracts of Bocconia frutescens, Miconia affinis, Myrcia splendens, Combretum aff.

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A library of 600 taxonomically diverse Panamanian plant extracts was screened for fungicidal, insecticidal, and herbicidal activities. A total of 19 active extracts were submitted to HPLC-based activity profiling, and extracts of Bocconia frutescens, Miconia affinis, Myrcia splendens, Combretum aff. laxum, and Erythroxylum macrophyllum were selected for the isolation of compounds. Chelerythrine (2), macarpine (3), dihydrosanguinarine (5), and arjunolic acid (8) showed moderate-to-good fungicidal activity. Myricetin-3-O-(6''-O-galloyl)-β-galactopyranoside (13) showed moderate insecticidal activity, but no compound with herbicidal activity was identified. Full article

Open AccessArticle Sample Entropy and Traditional Measures of Heart Rate Dynamics Reveal Different Modes of Cardiovascular Control During Low Intensity Exercise

by Matthias Weippert, Martin Behrens, Annika Rieger and Kristin Behrens

Entropy 2014, 16(11), 5698-5711; doi:10.3390/e16115698

Received: 24 September 2014 / Revised: 15 October 2014 / Accepted: 27 October 2014 / Published: 31 October 2014

Cited by 7 | Viewed by 1602 | PDF Full-text (696 KB) | HTML Full-text | XML Full-text

Abstract

Nonlinear parameters of heart rate variability (HRV) have proven their prognostic value in clinical settings, but their physiological background is not very well established. We assessed the effects of low intensity isometric (ISO) and dynamic (DYN) exercise of the lower limbs on heart

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Nonlinear parameters of heart rate variability (HRV) have proven their prognostic value in clinical settings, but their physiological background is not very well established. We assessed the effects of low intensity isometric (ISO) and dynamic (DYN) exercise of the lower limbs on heart rate matched intensity on traditional and entropy measures of HRV. Due to changes of afferent feedback under DYN and ISO a distinct autonomic response, mirrored by HRV measures, was hypothesized. Five-minute inter-beat interval measurements of 43 healthy males (26.0 ± 3.1 years) were performed during rest, DYN and ISO in a randomized order. Blood pressures and rate pressure product were higher during ISO vs. DYN (p < 0.001). HRV indicators SDNN as well as low and high frequency power were significantly higher during ISO (p < 0.001 for all measures). Compared to DYN, sample entropy (SampEn) was lower during ISO (p < 0.001). Concluding, contraction mode itself is a significant modulator of the autonomic cardiovascular response to exercise. Compared to DYN, ISO evokes a stronger blood pressure response and an enhanced interplay between both autonomic branches. Non-linear HRV measures indicate a more regular behavior under ISO. Results support the view of the reciprocal antagonism being only one of many modes of autonomic heart rate control. Under different conditions; the identical “end product” heart rate might be achieved by other modes such as sympathovagal co-activation as well. Full article

(This article belongs to the Special Issue Entropy and Cardiac Physics)

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Open AccessArticle Betulinic Acid Derivatives NVX-207 and B10 for Treatment of Glioblastoma—An in Vitro Study of Cytotoxicity and Radiosensitization

by Matthias Bache, Stephan Bernhardt, Sarina Passin, Henri Wichmann, Anja Hein, Martin P Zschornak, Matthias Kappler, Helge Taubert, Reinhard Paschke and Dirk Vordermark

Int. J. Mol. Sci. 2014, 15(11), 19777-19790; doi:10.3390/ijms151119777

Received: 27 May 2014 / Revised: 24 October 2014 / Accepted: 27 October 2014 / Published: 30 October 2014

Cited by 11 | Viewed by 1725 | PDF Full-text (1829 KB) | HTML Full-text | XML Full-text

Abstract

Betulinic acid (BA), a pentacyclic triterpene, represents a new therapeutic substance that has potential benefits for treating glioblastoma. Recently, new strategies for producing BA derivatives with improved properties have evolved. However, few studies have examined the combination of BA or BA derivatives using

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Betulinic acid (BA), a pentacyclic triterpene, represents a new therapeutic substance that has potential benefits for treating glioblastoma. Recently, new strategies for producing BA derivatives with improved properties have evolved. However, few studies have examined the combination of BA or BA derivatives using radiotherapy. The effects of two BA derivatives, NVX-207 and B10, on cellular and radiobiological behavior were analyzed using glioblastoma cell lines (U251MG, U343MG and LN229). Based on IC₅₀ values under normoxic conditions, we detected a 1.3–2.9-fold higher cytotoxicity of the BA derivatives B10 and NVX-207, respectively, compared to BA. Incubation using both BA derivatives led to decreased cell migration, cleavage of PARP and decreased protein expression levels of Survivin. Weak radiation sensitivity enhancement was observed in U251MG cells after treatment with both BA derivatives. The enhancement factors at an irradiation dose of 6 Gy after treatment with 5 µM NVX-207 and 5 µM B10 were 1.32 (p = 0.029) and 1.55 (p = 0.002), respectively. In contrast to BA, neither NVX-207 nor B10 had additional effects under hypoxic conditions. Our results suggest that the BA derivatives NVX-207 and B10 improve the effects of radiotherapy on human malignant glioma cells, particularly under normoxic conditions. Full article

(This article belongs to the collection Radiation Toxicity in Cells)

Open AccessArticle Directionality Theory and the Entropic Principle of Natural Selection

by Lloyd A. Demetrius and Volker Matthias Gundlach

Entropy 2014, 16(10), 5428-5522; doi:10.3390/e16105428

Received: 30 January 2013 / Revised: 13 August 2014 / Accepted: 15 September 2014 / Published: 20 October 2014

Cited by 5 | Viewed by 1641 | PDF Full-text (885 KB) | HTML Full-text | XML Full-text

Abstract

Darwinian fitness describes the capacity of an organism to appropriate resources from the environment and to convert these resources into net-offspring production. Studies of competition between related types indicate that fitness is analytically described by entropy, a statistical measure which is positively correlated

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Darwinian fitness describes the capacity of an organism to appropriate resources from the environment and to convert these resources into net-offspring production. Studies of competition between related types indicate that fitness is analytically described by entropy, a statistical measure which is positively correlated with population stability, and describes the number of accessible pathways of energy flow between the individuals in the population. Directionality theory is a mathematical model of the evolutionary process based on the concept evolutionary entropy as the measure of fitness. The theory predicts that the changes which occur as a population evolves from one non-equilibrium steady state to another are described by the following directionality principle–fundamental theorem of evolution: (a) an increase in evolutionary entropy when resource composition is diverse, and resource abundance constant; (b) a decrease in evolutionary entropy when resource composition is singular, and resource abundance variable. Evolutionary entropy characterizes the dynamics of energy flow between the individual elements in various classes of biological networks: (a) where the units are individuals parameterized by age, and their age-specific fecundity and mortality; where the units are metabolites, and the transitions are the biochemical reactions that convert substrates to products; (c) where the units are social groups, and the forces are the cooperative and competitive interactions between the individual groups. % This article reviews the analytical basis of the evolutionary entropic principle, and describes applications of directionality theory to the study of evolutionary dynamics in two biological systems; (i) social networks–the evolution of cooperation; (ii) metabolic networks–the evolution of body size. Statistical thermodynamics is a mathematical model of macroscopic behavior in inanimate matter based on entropy, a statistical measure which describes the number of ways the molecules that compose the a material aggregate can be arranged to attain the same total energy. This theory predicts an increase in thermodynamic entropy as the system evolves towards its equilibrium state. We will delineate the relation between directionality theory and statistical thermodynamics, and review the claim that the entropic principle for thermodynamic systems is the limit, as the resource production rate tends to zero, and population size tends to infinity, of the entropic principle for evolutionary systems. Full article

Open AccessArticle A Note on Distance-based Graph Entropies

by Zengqiang Chen, Matthias Dehmer and Yongtang Shi

Entropy 2014, 16(10), 5416-5427; doi:10.3390/e16105416

Received: 26 July 2014 / Revised: 18 September 2014 / Accepted: 15 October 2014 / Published: 20 October 2014

Cited by 23 | Viewed by 1358 | PDF Full-text (161 KB) | HTML Full-text | XML Full-text

Abstract

A variety of problems in, e.g., discrete mathematics, computer science, information theory, statistics, chemistry, biology, etc., deal with inferring and characterizing relational structures by using graph measures. In this sense, it has been proven that information-theoretic quantities representing graph entropies possess useful properties

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A variety of problems in, e.g., discrete mathematics, computer science, information theory, statistics, chemistry, biology, etc., deal with inferring and characterizing relational structures by using graph measures. In this sense, it has been proven that information-theoretic quantities representing graph entropies possess useful properties such as a meaningful structural interpretation and uniqueness. As classical work, many distance-based graph entropies, e.g., the ones due to Bonchev et al. and related quantities have been proposed and studied. Our contribution is to explore graph entropies that are based on a novel information functional, which is the number of vertices with distance \(k\) to a given vertex. In particular, we investigate some properties thereof leading to a better understanding of this new information-theoretic quantity. Full article

(This article belongs to the Special Issue Complex Systems and Nonlinear Dynamics)

Open AccessArticle Screening of Panamanian Plants for Cosmetic Properties, and HPLC-Based Identification of Constituents with Antioxidant and UV-B Protecting Activities

by Niels GULDBRANDSEN, Maria DE MIERI, Mahabir GUPTA, Eleni LIAKOU, Harris PRATSINIS, Dimitris KLETSAS, Eliza CHAITA, Nektarios ALIGIANNIS, Alexios-Leandros SKALTSOUNIS and Matthias HAMBURGER

Sci. Pharm. 2015, 83(1), 177-190; doi:10.3797/scipharm.1409-12

Received: 21 September 2014 / Accepted: 15 October 2014 / Published: 15 October 2014

Cited by 4 | Viewed by 167 | PDF Full-text (423 KB) | Supplementary Files

Abstract

A library of 600 taxonomically diverse Panamanian plant extracts was screened for DPPH scavenging and UV-B protective activities, and the methanolic extracts of Mosquitoxylum jamaicense, Combretum cacoucia, and Casearia commersionia were submitted to HPLC-based activity profiling. The compounds located in the

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A library of 600 taxonomically diverse Panamanian plant extracts was screened for DPPH scavenging and UV-B protective activities, and the methanolic extracts of Mosquitoxylum jamaicense, Combretum cacoucia, and Casearia commersionia were submitted to HPLC-based activity profiling. The compounds located in the active time windows were isolated and identified as gallic acid derivatives and flavonoids. Gallic acid methyl ester (3) and digallic acid derivatives (2, 6) showed the highest DPPH scavenging activity (<10 μg/mL), while protocatechuic acid (7) and isoquercitrin (10) exhibited the highest UV-B protective properties. Full article

Open AccessArticle The Effect of Different Global Navigation Satellite System Methods on Positioning Accuracy in Elite Alpine Skiing

by Matthias Gilgien, Jörg Spörri, Philippe Limpach, Alain Geiger and Erich Müller

Sensors 2014, 14(10), 18433-18453; doi:10.3390/s141018433

Received: 6 April 2014 / Revised: 17 September 2014 / Accepted: 18 September 2014 / Published: 3 October 2014

Cited by 10 | Viewed by 2510 | PDF Full-text (538 KB) | HTML Full-text | XML Full-text

Abstract

In sport science, Global Navigation Satellite Systems (GNSS) are frequently applied to capture athletes’ position, velocity and acceleration. Application of GNSS includes a large range of different GNSS technologies and methods. To date no study has comprehensively compared the different GNSS methods applied.

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In sport science, Global Navigation Satellite Systems (GNSS) are frequently applied to capture athletes’ position, velocity and acceleration. Application of GNSS includes a large range of different GNSS technologies and methods. To date no study has comprehensively compared the different GNSS methods applied. Therefore, the aim of the current study was to investigate the effect of differential and non-differential solutions, different satellite systems and different GNSS signal frequencies on position accuracy. Twelve alpine ski racers were equipped with high-end GNSS devices while performing runs on a giant slalom course. The skiers’ GNSS antenna positions were calculated in three satellite signal obstruction conditions using five different GNSS methods. The GNSS antenna positions were compared to a video-based photogrammetric reference system over one turn and against the most valid GNSS method over the entire run. Furthermore, the time for acquisitioning differential GNSS solutions was assessed for four differential methods. The only GNSS method that consistently yielded sub-decimetre position accuracy in typical alpine skiing conditions was a differential method using American (GPS) and Russian (GLONASS) satellite systems and the satellite signal frequencies L1 and L2. Under conditions of minimal satellite signal obstruction, valid results were also achieved when either the satellite system GLONASS or the frequency L2 was dropped from the best configuration. All other methods failed to fulfill the accuracy requirements needed to detect relevant differences in the kinematics of alpine skiers, even in conditions favorable for GNSS measurements. The methods with good positioning accuracy had also the shortest times to compute differential solutions. This paper highlights the importance to choose appropriate methods to meet the accuracy requirements for sport applications. Full article

(This article belongs to the Section Physical Sensors)

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Open AccessArticle Effects of Endurance Exercise Training and Crataegus Extract WS^® 1442 in Patients with Heart Failure with Preserved Ejection Fraction – A Randomized Controlled Trial

by Sascha Härtel, Claire Kutzner, Eva Westphal, Matthias Limberger, Martin Burkart, Ulrich Ebner-Priemer, Matthias Kohl-Bareis and Klaus Bös

Sports 2014, 2(3), 59-75; doi:10.3390/sports2030059

Received: 22 July 2014 / Revised: 22 August 2014 / Accepted: 14 September 2014 / Published: 24 September 2014

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Abstract

Impaired exercise capacity is the core symptom of heart failure with preserved ejection fraction (HFpEF). We assessed effects of exercise training and Crataegus extract WS 1442 in HFpEF and aimed to identify mechanisms of action in an exploratory trial (German Clinical Trials Register

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Impaired exercise capacity is the core symptom of heart failure with preserved ejection fraction (HFpEF). We assessed effects of exercise training and Crataegus extract WS 1442 in HFpEF and aimed to identify mechanisms of action in an exploratory trial (German Clinical Trials Register DRKS00000259). 140 sedentary HFpEF NYHA II patients on standard treatment received eight weeks of aerobic endurance training and half were randomized to WS 1442 900 mg/day. Symptoms, 2 km walking time (T_2km), parameters of exercise tolerance, cardiac and vascular function, muscular efficiency and skeletal muscular haemoglobin oxygen saturation (SO₂) measured during a treadmill protocol were captured at baseline and after eight weeks. Adverse events were recorded during the trial. Mechanisms of action were explored by correlation and path analyses of changes. Symptoms and exercise capacity improved with training, but correlations between improvements were low and path models were rejected. SO₂ increased, decreased or undulated with increasing exercise intensity in individual patients and was not altered by training. WS 1442 improved T_2km (-12.7% vs. -8.4%, p = 0.019), tended to improve symptoms and to pronounce SO₂-decrease with increasing exercise, an indicator of oxygen utilisation. Endurance training and WS 1442 were safe and well tolerated in combination with standard drug treatment. Full article

(This article belongs to the Special Issue Sports Medicine)

Open AccessArticle Genetic Diversity in Jatropha curcas L. Assessed with SSR and SNP Markers

by Juan M. Montes, Frank Technow, Matthias Martin and Klaus Becker

Diversity 2014, 6(3), 551-566; doi:10.3390/d6030551

Received: 5 June 2014 / Revised: 30 July 2014 / Accepted: 31 July 2014 / Published: 7 August 2014

Cited by 10 | Viewed by 2314 | PDF Full-text (311 KB) | HTML Full-text | XML Full-text

Abstract

Jatropha curcas L. (jatropha) is an undomesticated plant that has recently received great attention for its utilization in biofuel production, rehabilitation of wasteland, and rural development. Knowledge of genetic diversity and marker-trait associations is urgently needed for the design of breeding strategies. The

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Jatropha curcas L. (jatropha) is an undomesticated plant that has recently received great attention for its utilization in biofuel production, rehabilitation of wasteland, and rural development. Knowledge of genetic diversity and marker-trait associations is urgently needed for the design of breeding strategies. The main goal of this study was to assess the genetic structure and diversity in jatropha germplasm with co-dominant markers (Simple Sequence Repeats (SSR) and Single Nucleotide Polymorphism (SNP) in a diverse, worldwide, germplasm panel of 70 accessions. We found a high level of homozygosis in the germplasm that does not correspond to the purely outcrossing mating system assumed to be present in jatropha. We hypothesize that the prevalent mating system of jatropha comprise a high level of self-fertilization and that the outcrossing rate is low. Genetic diversity in accessions from Central America and Mexico was higher than in accession from Africa, Asia, and South America. We identified makers associated with the presence of phorbol esters. We think that the utilization of molecular markers in breeding of jatropha will significantly accelerate the development of improved cultivars. Full article

Open AccessArticle Hydrological Implications of Covering Wind-Blown Snow Accumulations with Geotextiles on Mount Aragats, Armenia

by Alexander Nestler, Matthias Huss, Rouben Ambartzumian and Artak Hambarian

Geosciences 2014, 4(3), 73-92; doi:10.3390/geosciences4030073

Received: 29 April 2014 / Revised: 16 June 2014 / Accepted: 25 June 2014 / Published: 2 July 2014

Cited by 1 | Viewed by 1640 | PDF Full-text (11411 KB) | HTML Full-text | XML Full-text

Abstract

Snow is an excellent water reservoir, naturally storing large quantities of water at time scales from a few days to several months. In summer-dry countries, like Armenia, runoff due to snow melt from mountain regions is highly important for a sustained water supply

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Snow is an excellent water reservoir, naturally storing large quantities of water at time scales from a few days to several months. In summer-dry countries, like Armenia, runoff due to snow melt from mountain regions is highly important for a sustained water supply (irrigation, hydropower). Snow fields on Mount Aragats, Armenia’s highest peak, often persist until July, providing vital amounts of melt water. Artificially managing these wind-driven snow accumulations as a natural water reservoir might have considerable potential. In the context of the Swiss-Armenian joint venture, Freezwater, snow fields are covered with geotextiles in order to delay snow melt long enough to provide additional melt water in the dry season of the year. In this study, we analyze the hydrological effectiveness of the artificial management of the natural snow cover on Mount Aragats based on various field measurements acquired over a three-year period and numerical modeling. Over the winter season, partly more than five meter-thick snow deposits are formed supported by snow redistribution by strong wind. Repeated mappings of snow fields indicate that snow cover patterns remain highly consistent over time. Measurements of ablation below manually applied geotextiles show a considerable reduction of melt rates by more than 50%. Simulations with an energy-balance model and a distributed temperature-index model allow assessing the hydrological effect of artificial snow management for different initial snow depths and elevations and suggest that coverage is needed at a large scale in order to generate a significant impact on discharge. Full article

Open AccessArticle MAD-MEX: Automatic Wall-to-Wall Land Cover Monitoring for the Mexican REDD-MRV Program Using All Landsat Data

by Steffen Gebhardt, Thilo Wehrmann, Miguel Angel Muñoz Ruiz, Pedro Maeda, Jesse Bishop, Matthias Schramm, Rene Kopeinig, Oliver Cartus, Josef Kellndorfer, Rainer Ressl, Lucio Andrés Santos and Michael Schmidt

Remote Sens. 2014, 6(5), 3923-3943; doi:10.3390/rs6053923

Received: 31 January 2014 / Revised: 29 March 2014 / Accepted: 9 April 2014 / Published: 30 April 2014

Cited by 11 | Viewed by 3928 | PDF Full-text (4278 KB) | HTML Full-text | XML Full-text

Abstract

Estimating forest area at a national scale within the United Nations program of Reducing Emissions from Deforestation and Forest Degradation (REDD) is primarily based on land cover information using remote sensing technologies. Timely delivery for a country of a size like Mexico can

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Estimating forest area at a national scale within the United Nations program of Reducing Emissions from Deforestation and Forest Degradation (REDD) is primarily based on land cover information using remote sensing technologies. Timely delivery for a country of a size like Mexico can only be achieved in a standardized and cost-effective manner by automatic image classification. This paper describes the operational land cover monitoring system for Mexico. It utilizes national-scale cartographic reference data, all available Landsat satellite imagery, and field inventory data for validation. Seven annual national land cover maps between 1993 and 2008 were produced. The classification scheme defined 9 and 12 classes at two hierarchical levels. Overall accuracies achieved were up to 76%. Tropical and temperate forest was classified with accuracy up to 78% and 82%, respectively. Although specifically designed for the needs of Mexico, the general process is suitable for other participating countries in the REDD+ program to comply with guidelines on standardization and transparency of methods and to assure comparability. However, reporting of change is ill-advised based on the annual land cover products and a combination of annual land cover and change detection algorithms is suggested. Full article

Open AccessArticle Characterization of High-k Nanolayers by Grazing Incidence X-ray Spectrometry

by Matthias Müller, Philipp Hönicke, Blanka Detlefs and Claudia Fleischmann

Materials 2014, 7(4), 3147-3159; doi:10.3390/ma7043147

Received: 21 January 2014 / Revised: 27 March 2014 / Accepted: 8 April 2014 / Published: 17 April 2014

Cited by 11 | Viewed by 2623 | PDF Full-text (697 KB) | HTML Full-text | XML Full-text

Abstract

The accurate characterization of nanolayered systems is an essential topic for today’s developments in many fields of material research. Thin high-k layers and gate stacks are technologically required for the design of current and future electronic devices and can be deposited, e.g., by

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The accurate characterization of nanolayered systems is an essential topic for today’s developments in many fields of material research. Thin high-k layers and gate stacks are technologically required for the design of current and future electronic devices and can be deposited, e.g., by Atomic Layer Deposition (ALD). However, the metrological challenges to characterize such systems demand further development of analytical techniques. Reference-free Grazing Incidence X-ray Fluorescence (GIXRF) based on synchrotron radiation can significantly contribute to the characterization of such nanolayered systems. GIXRF takes advantage of the incident angle dependence of XRF, in particular below the substrate’s critical angle where changes in the X-ray Standing Wave field (XSW) intensity influence the angular intensity profile. The reliable modeling of the XSW in conjunction with the radiometrically calibrated instrumentation at the PTB allows for reference-free, fundamental parameter-based quantitative analysis. This approach is very well suited for the characterization of nanoscaled materials, especially when no reference samples with sufficient quality are available. The capabilities of this method are demonstrated by means of two systems for transistor gate stacks, i.e., Al₂O₃ high-k layers grown on Si or Si/SiO₂ and Sc₂O₃ layers on InGaAs/InP substrates. Full article

(This article belongs to the Special Issue High-k Materials and Devices 2014)

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Open AccessReview More Novel Hantaviruses and Diversifying Reservoir Hosts — Time for Development of Reservoir-Derived Cell Culture Models?

by Isabella Eckerle, Matthias Lenk and Rainer G. Ulrich

Viruses 2014, 6(3), 951-967; doi:10.3390/v6030951

Received: 12 December 2013 / Revised: 11 February 2014 / Accepted: 15 February 2014 / Published: 26 February 2014

Cited by 6 | Viewed by 2000 | PDF Full-text (718 KB) | HTML Full-text | XML Full-text

Abstract

Due to novel, improved and high-throughput detection methods, there is a plethora of newly identified viruses within the genus Hantavirus. Furthermore, reservoir host species are increasingly recognized besides representatives of the order Rodentia, now including members of the mammalian orders Soricomorpha/Eulipotyphla and

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Due to novel, improved and high-throughput detection methods, there is a plethora of newly identified viruses within the genus Hantavirus. Furthermore, reservoir host species are increasingly recognized besides representatives of the order Rodentia, now including members of the mammalian orders Soricomorpha/Eulipotyphla and Chiroptera. Despite the great interest created by emerging zoonotic viruses, there is still a gross lack of in vitro models, which reflect the exclusive host adaptation of most zoonotic viruses. The usually narrow host range and genetic diversity of hantaviruses make them an exciting candidate for studying virus-host interactions on a cellular level. To do so, well-characterized reservoir cell lines covering a wide range of bat, insectivore and rodent species are essential. Most currently available cell culture models display a heterologous virus-host relationship and are therefore only of limited value. Here, we review the recently established approaches to generate reservoir-derived cell culture models for the in vitro study of virus-host interactions. These successfully used model systems almost exclusively originate from bats and bat-borne viruses other than hantaviruses. Therefore we propose a parallel approach for research on rodent- and insectivore-borne hantaviruses, taking the generation of novel rodent and insectivore cell lines from wildlife species into account. These cell lines would be also valuable for studies on further rodent-borne viruses, such as orthopox- and arenaviruses. Full article

(This article belongs to the Special Issue Hantaviruses)

Open AccessArticle Clinical Documentation and Data Transfer from Ebola and Marburg Virus Disease Wards in Outbreak Settings: Health Care Workers’ Experiences and Preferences

by Silja Bühler, Paul Roddy, Ellen Nolte and Matthias Borchert

Viruses 2014, 6(2), 927-937; doi:10.3390/v6020927

Received: 13 December 2013 / Revised: 8 February 2014 / Accepted: 11 February 2014 / Published: 19 February 2014

Abstract

Understanding human filovirus hemorrhagic fever (FHF) clinical manifestations and evaluating treatment strategies require the collection of clinical data in outbreak settings, where clinical documentation has been limited. Currently, no consensus among filovirus outbreak-response organisations guides best practice for clinical documentation and data transfer.

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Understanding human filovirus hemorrhagic fever (FHF) clinical manifestations and evaluating treatment strategies require the collection of clinical data in outbreak settings, where clinical documentation has been limited. Currently, no consensus among filovirus outbreak-response organisations guides best practice for clinical documentation and data transfer. Semi-structured interviews were conducted with health care workers (HCWs) involved in FHF outbreaks in sub-Saharan Africa, and with HCWs experienced in documenting and transferring data from high-risk areas (isolation wards or biosafety level 4 laboratories). Methods for data documentation and transfer were identified, described in detail and categorised by requirement for electricity and ranked by interviewee preference. Some methods involve removing paperwork and other objects from the filovirus disease ward without disinfection. We believe that if done properly, these methods are reasonably safe for certain settings. However, alternative methods avoiding the removal of objects, or involving the removal of paperwork or objects after non-damaging disinfection, are available. These methods are not only safer, they are also perceived as safer and likely more acceptable to health workers and members of the community. The use of standardised clinical forms is overdue. Experiments with by sunlight disinfection should continue, and non-damaging disinfection of impregnated paper, suitable tablet computers and underwater cameras should be evaluated under field conditions. Full article

(This article belongs to the collection Advances in Ebolavirus, Marburgvirus, and Cuevavirus Research)

Open AccessArticle Comparability of in Vitro Tests for Bioactive Nanoparticles: A Common Assay to Detect Reactive Oxygen Species as an Example

by Matthias Roesslein, Cordula Hirsch, Jean-Pierre Kaiser, Harald F. Krug and Peter Wick

Int. J. Mol. Sci. 2013, 14(12), 24320-24337; doi:10.3390/ijms141224320

Received: 23 October 2013 / Revised: 10 December 2013 / Accepted: 11 December 2013 / Published: 13 December 2013

Cited by 14 | Viewed by 1951 | PDF Full-text (829 KB) | HTML Full-text | XML Full-text

Abstract

The release of reactive oxygen species (ROS) during the electron transport of mitochondrial aerobic respiration is the major source of ROS. However, contact between cells and nanoparticles (NPs) can also induce release of ROS, leading to an imbalance towards the pro-oxidative state. At

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The release of reactive oxygen species (ROS) during the electron transport of mitochondrial aerobic respiration is the major source of ROS. However, contact between cells and nanoparticles (NPs) can also induce release of ROS, leading to an imbalance towards the pro-oxidative state. At low levels of ROS production, cells initiate a protective response to guarantee their survival, but an excess of ROS can damage cellular compounds such as membranes and various organelles, or directly cause genotoxicity. Thus an elevated level of ROS is an important indicator of cellular stress and an accurate recording of this parameter would be very informative. ROS can be measured by various assays, but all known assays measuring and quantifying ROS possess certain weaknesses. The problems and challenges of quantitatively detecting ROS in vitro using the 2',7'-dichlorodihydrofluorescein (DCF) assay is discussed as an example. In addition, we debate the difficulties in finding a suitable and stable chemical reaction control for the DCF assay (or other ROS-detecting assays). As a conclusion, we believe that using 3-morpholinosydnonimine hydrochloride (Sin-1) as a ROS inducer in the DCF assay is feasible only qualitatively. However, a quantitative measurement of the absolute amount of ROS produced and a quantitative comparison between experiments is (at the moment) impossible. Full article

(This article belongs to the Special Issue Bioactive Nanoparticles 2014)

Open AccessArticle A Liquid Inorganic Electrolyte Showing an Unusually High Lithium Ion Transference Number: A Concentrated Solution of LiAlCl₄ in Sulfur Dioxide

by Robert Hartl, Matthias Fleischmann, Ruth M. Gschwind, Martin Winter and Heiner Jakob Gores

Energies 2013, 6(9), 4448-4464; doi:10.3390/en6094448

Received: 25 June 2013 / Revised: 5 August 2013 / Accepted: 21 August 2013 / Published: 29 August 2013

Cited by 2 | Viewed by 2391 | PDF Full-text (402 KB) | HTML Full-text | XML Full-text

Abstract

We report on studies of an inorganic electrolyte: LiAlCl₄ in liquid sulfur dioxide. Concentrated solutions show a very high conductivity when compared with typical electrolytes for lithium ion batteries that are based on organic solvents. Our investigations include conductivity measurements and measurements

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We report on studies of an inorganic electrolyte: LiAlCl₄ in liquid sulfur dioxide. Concentrated solutions show a very high conductivity when compared with typical electrolytes for lithium ion batteries that are based on organic solvents. Our investigations include conductivity measurements and measurements of transference numbers via nuclear magnetic resonance (NMR) and by a classical direct method, Hittorf’s method. For the use of Hittorf’s method, it is necessary to measure the concentration of the electrolyte in a selected cell compartment before and after electrochemical polarization very precisely. This task was finally performed by potentiometric titration after hydrolysis of the salt. The Haven ratio was determined to estimate the association behavior of this very concentrated electrolyte solution. The measured unusually high transference number of the lithium cation of the studied most concentrated solution, a molten solvate LiAlCl₄ × 1.6SO₂, makes this electrolyte a promising alternative for lithium ion cells with high power ability. Full article

(This article belongs to the Special Issue Li-ion Batteries and Energy Storage Devices)

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Open AccessReview Current Staging Procedures in Urinary Bladder Cancer

by Tobias Maurer, Thomas Horn, Matthias Heck, Jürgen E. Gschwend, Matthias Eiber and Ambros J. Beer

Diagnostics 2013, 3(3), 315-324; doi:10.3390/diagnostics3030315

Received: 17 May 2013 / Revised: 13 June 2013 / Accepted: 18 June 2013 / Published: 25 June 2013

Cited by 4 | Viewed by 2893 | PDF Full-text (327 KB) | HTML Full-text | XML Full-text

Abstract

Currently computed tomography (CT) represents the most widely used standard imaging modality in muscle-invasive urinary bladder cancer. Visualization of local tumor or depth of invasion as well as lymph node staging, however, is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination

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Currently computed tomography (CT) represents the most widely used standard imaging modality in muscle-invasive urinary bladder cancer. Visualization of local tumor or depth of invasion as well as lymph node staging, however, is often impaired. Magnetic resonance imaging (MRI) with diffusion-weighted sequences, determination of apparent diffusion coefficient (ADC) values or utilization of superparamagnetic iron nanoparticles potentially exhibits advantages in the assessment of local tumor or lymph node involvement and therefore might play a role in routine staging of urinary bladder cancer in the future. Likewise, positron emission tomography (PET) with the currently utilized tracers ¹⁸F-FDG, ¹¹C-choline and ¹¹C-acetate is investigated in bladder cancer patients—mostly in combination with diagnostic CT. Although promising results could be obtained for these PET/CT examinations in smaller series, their true value cannot be determined at present. Full article

(This article belongs to the Special Issue Advance in Molecular Diagnostics and Imaging)

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Open AccessReview Membrane Drug Transporters and Chemoresistance in Human Pancreatic Carcinoma

by Wolfgang Hagmann, Ralf Faissner, Martina Schnölzer, Matthias Löhr and Ralf Jesnowski

Cancers 2011, 3(1), 106-125; doi:10.3390/cancers3010106

Received: 1 December 2010 / Revised: 10 December 2010 / Accepted: 24 December 2010 / Published: 30 December 2010

Cited by 7 | Viewed by 4757 | PDF Full-text (654 KB) | HTML Full-text | XML Full-text

Abstract

Pancreatic cancer ranks among the tumors most resistant to chemotherapy. Such chemoresistance of tumors can be mediated by various cellular mechanisms including dysregulated apoptosis or ineffective drug concentration at the intracellular target sites. In this review, we highlight recent advances in experimental chemotherapy

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Pancreatic cancer ranks among the tumors most resistant to chemotherapy. Such chemoresistance of tumors can be mediated by various cellular mechanisms including dysregulated apoptosis or ineffective drug concentration at the intracellular target sites. In this review, we highlight recent advances in experimental chemotherapy underlining the role of cellular transporters in drug resistance. Such contribution to the chemoresistant phenotype of tumor cells or tissues can be conferred both by uptake and export transporters, as demonstrated by in vivo and in vitro data. Our studies used human pancreatic carcinoma cells, cells stably transfected with human transporter cDNAs, or cells in which a specific transporter was knocked down by RNA interference. We have previously shown that 5-fluorouracil treatment affects the expression profile of relevant cellular transporters including multidrug resistance proteins (MRPs), and that MRP5 (ABCC5) influences chemoresistance of these tumor cells. Similarly, cell treatment with the nucleoside drug gemcitabine or a combination of chemotherapeutic drugs can variably influence the expression pattern and relative amount of uptake and export transporters in pancreatic carcinoma cells or select for pre-existing subpopulations. In addition, cytotoxicity studies with MRP5-overexpressing or MRP5-silenced cells demonstrate a contribution of MRP5 also to gemcitabine resistance. These data may lead to improved strategies of future chemotherapy regimens using gemcitabine and/or 5-fluorouracil. Full article

(This article belongs to the Special Issue Pancreatic Cancer)

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Open AccessArticle Effect of Different Metal Ions on the Biological Properties of Cefadroxil

by Sayed H. Auda, Ilka Knütter, Beate Bretschneider, Matthias Brandsch, Yahya Mrestani, Cornelia Große and Reinhard H. H. Neubert

Pharmaceuticals 2009, 2(3), 184-193; doi:10.3390/ph2030184

Received: 9 October 2009 / Revised: 9 November 2009 / Accepted: 1 December 2009 / Published: 15 December 2009

Cited by 3 | Viewed by 6708 | PDF Full-text (174 KB) | HTML Full-text | XML Full-text

Abstract

The effect of different metal ions on the intestinal transport and the antibacterial activity of cefadroxil [(6R,7R)-7-{[(2R)-2-amino-2-(4-hydroxyphenyl)acetyl]amino}-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid] was investigated. The [¹⁴C]Gly-Sar uptake via PEPT1 was inhibited by Zn²⁺ and Cu²⁺ treatment in

[...] Read more.

The effect of different metal ions on the intestinal transport and the antibacterial activity of cefadroxil [(6R,7R)-7-{[(2R)-2-amino-2-(4-hydroxyphenyl)acetyl]amino}-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid] was investigated. The [¹⁴C]Gly-Sar uptake via PEPT1 was inhibited by Zn²⁺ and Cu²⁺ treatment in a concentration-dependent manner (K_i values 107 ± 23 and 19 ± 5 μM, respectively). Kinetic analysis showed that the K_t of Gly-Sar uptake was increased 2-fold in the presence of zinc sulphate (150 μM) whereas the V_max value were not affected suggesting that zinc ions inhibited Gly-Sar uptake by PEPT1 in a competitively manner. Ni²⁺ exhibited moderate inhibitory effect, whereas Co²⁺, Mg²⁺, Al³⁺ ions showed no inhibitory effect on Gly-Sar uptake via PEPT1. Subsequently, we examined the effect of Zn²⁺ and Al³⁺ ions on the transepithelial transport of cefadroxil across Caco-2 cells cultured on permeable supports. The results showed that zinc ions inhibited the transepithelial flux of cefadroxil at Caco-2 cell monolayers while Al³⁺ ions had no effect. The interaction of cephalosporins with the metal ions could suggest negative effects of some metal ions on the clinical aspects of small intestinal peptide and drug transport. Finally, the effect of Zn²⁺, Cu²⁺ and Al³⁺ ions on the antibacterial activity of cefadroxil was tested. It was found that there is no significant difference between the activity of cefadroxil and the cefadroxil metal ion complexes studied against the investigated sensitive bacterial species. Full article

(This article belongs to the Special Issue Anti-Infective Agents)

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