Study of hemocompatibility and endothelial cell interaction of tecoflex-based electrospun vascular grafts

Abstract

Ensuring long-term functioning and efficient endothelialization of small diameter vascular grafts (VG) is an urgent task of tissue engineering. A solution may be to use electrospun VGs prepared from blends polyurethane with gelatin and/or bivalirudin. Here, properties of 3D matrices were explored by SEM, contact angle measurements and IR spectroscopy, and their interaction with blood and endothelial cells was studied. Introduction of gelatin into matrices enhanced adhesion and proliferation of endotheliocytes and enabled adhesion of platelets, whereas bivalirudin inhibited platelet adhesion while having no negative effect on the adhesion and proliferation of endothelial cells.     

Stereoisomere Aromastoffe

Zusammenfassung Die Synthese von acht verschiedenen 2-Alkoxy-5-alkyl-tetrahydrofuranen und ihren Stereoisomeren wird vorgestellt, sieben von ihnen sind als Aromastoffe der Wassermelone bekannt. Alle Stereoisomeren werden, ausgehend von optisch reinen-Nonalacton-Enantiomeren, synthetisiert und mit Diisobutylaluminiumhydrid selektiv zu den entsprechenden Lactolen reduziert. Die Lactole werden mit den gewünschten Alkoholen in schwach saurer Lösung zucis/trans-Diastereomeren umgesetzt und durch Flüssigchromatographie in optisch reine Stereoisomere getrennt. Die sensorische Charakteristik aller Stereoisomeren der sieben Verbindungen wird aufgezeigt. Die Trennung dercis/trans-Diastereomeren an DB-210 wird vorgestellt und die chirospezifische Differenzierung der acht Verbindungen diskutiert.

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Stereoisomeric flavour compounds L. Optically pure 2-alkoxy-5-alkyl-tetrahydrofurans — structures and properties

Summary The synthesis of eight different 2-alkoxy-5-alkyltetrahydrofurans and their stereoisomers is presented, seven of which are known to be flavour compounds of water melons. All stereoisomers were synthesized from optically pure-lactone enantiomers, which were selectively reduced by diisobutylaluminium hydride to the corresponding lactols. The lactols were treated with the desired alcohol component in weakly acidic media to yield thecis/trans diastereoisomers, which were separated into optically pure stereoisomers by liquid chromatography. The sensory characteristics of all four stereoisomers of the seven compounds are given. The Stereodifferentiation of thesecis/trans diastereoisomers on DB-210 is demonstrated and the direct chirospecific differentiation of all eight compounds discussed.

     

A New Research Infrastructure for Investigating Flow Hydraulics and Process Equipment at Critical Fluid Properties

An optimized equipment design for natural gas processing and liquefaction plants becomes increasingly difficult with changing process conditions: Particularly low values of surface tension create rising challenges on the design of phase separators and column internals. The TERESA test rig at HZDR was designed to allow the investigation of multiphase thermohydraulics and phase separator performance under critical fluid properties in industrial dimensions. A versatile pipe test section is available in DN200 and equipment internals may be tested in a sectional DN300/DN500 test separator. The applied test fluid shows a high vapor-liquid density difference between 1470 and 940 kg m⁻³, viscosity as low as 0.12 mm²s⁻¹, and surface tension down to 1.3 mN m⁻¹. Volumetric liquid and vapor flow rates may be varied up to 9 and 530 m³h⁻¹ in the test rig, respectively.     

The influence of poly(3,4-ethylenedioxythiophene) modification on the transport properties and fuel cell performance of Nafion-117 membranes

Nafion-117/PEDOT composite membranes were synthesized by in situ chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) using ammonium persulfate as an oxidant. The polymerization of EDOT in Nafion membranes for various EDOT/oxidant treatment sequences was studied for the first time. PEDOT introduction leads to a slight decrease in both the ion-exchange capacity and water uptake of the composite membranes, as well as to an increase in cationic transport. Membranes initially treated with an oxidant exhibit better conductivity and lower hydrogen permeability. The effect of both modification of Nafion-117 membranes by PEDOT and hot-pressing of hydrogen-oxygen membrane-electrode assemblies (MEAs) on the performance of proton-exchange membrane fuel cells was studied. The maximum power density of the fabricated MEAs increases 1.5-fold: from 510 (for a pristine Nafion-117 membrane) to 810 mW cm⁻² (for a membrane modified by PEDOT). The current density at a voltage of 0.4 V reaches 1248 and 2246 mA cm⁻², respectively.     

Tetranorsesquiterpenoids as Attractants of Yucca Moths to Yucca Flowers

Journal of Chemical Ecology - The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur...     

Segmentation of the fascia lata and reproducible quantification of intermuscular adipose tissue (IMAT) of the thigh

Magnetic Resonance Materials in Physics, Biology and Medicine - To develop a precise semi-automated segmentation of the fascia lata (FL) of the thigh to quantify IMAT volume in T1w MR images and...     

Effect of the marine environment on reinforced concrete durability in Iberoamerican countries: DURACON project/CYTED

This work presents some of the results from the project: “Effect of the environment on reinforcement durability” (DURACON) in its first two-years period, which investigates the influence of urban and marine meteorochemical parameters on the performance of reinforced concrete structures. The results presented in this investigation are from 21 marine test sites only (no urban environments are included), distributed among 11 countries (Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Mexico, Spain, Uruguay, Portugal and Venezuela). The environment was evaluated using ISO Standard 9223 and the concrete was characterized by measuring compressive strength, elastic modulus, total and effective porosity, chloride permeability according to ASTM standards, as well as the effective porosity and resistance to water absorption using the Fagerlund method. To that effect, concrete specimens (with and without reinforcement) were prepared for electrochemical and physical/mechanical/chemical tests using the existing materials in each participating country, following strict procedures which enabled the preparation of similar concrete samples. Two water/cement (w/c) ratios (0.45 and 0.65) were selected, where the concrete with 0.45 w/c ratio had to have a minimum cement content of 400 kg/m³ and the one with 0.65 w/c ratio a compressive strength of 210 kg/cm². Type I Portland cement, siliceous sand, and crushed rock as coarse aggregates (13-mm maximum nominal size) were used. After a one-year exposure, the results of the corrosion potentiality and probability analysis of the reinforcement in the different test stations showed that, for marine atmospheres, the most aggressive environment to induce steel corrosion was at Portugal’s Cabo Raso station, and the least aggressive one was at Chile’s Valparaíso station. These results are comparable with the ones found using electrochemical measurements, after a two-year exposure.     

Toward Self‐Motivated,Cognitive, Continually Planning Agents

We present a flexible initial framework for defining self‐motivated, self‐aware agents in simulated worlds, planning continuously so as to maximize long‐term rewards. While such agents employ reasoned exploration of feasible sequences of actions and corresponding states, they also behave opportunistically and recover from failure, thanks to their continual plan updates and quest for rewards. Our framework allows for both specific and general (quantified) knowledge and for epistemic predicates such as knowing‐that and knowing‐whether. Because realistic agents have only partial knowledge of their world, the reasoning of the proposed agents uses a weakened closed‐world assumption; this has consequences for epistemic reasoning, in particular introspection. The planning operators allow for quantitative, gradual change and side effects such as the passage of time, changes in distances and rewards, and language production, using a uniform procedural attachment method. Question answering (involving introspection) and experimental runs are shown for our particular agent ME in a simple world, demonstrating the value of continual deliberate, reward‐driven planning. Though the primary merit of agents definable in our framework is that they combine all of the aforementioned features, they can also be configured as single or multiple goal‐seeking agents and as such perform comparably with some recent experimental agents.     

On the evaluation of unsupervised outlier detection: measures,datasets, and an empirical study

The evaluation of unsupervised outlier detection algorithms is a constant challenge in data mining research. Little is known regarding the strengths and weaknesses of different standard outlier detection models, and the impact of parameter choices for these algorithms. The scarcity of appropriate benchmark datasets with ground truth annotation is a significant impediment to the evaluation of outlier methods. Even when labeled datasets are available, their suitability for the outlier detection task is typically unknown. Furthermore, the biases of commonly-used evaluation measures are not fully understood. It is thus difficult to ascertain the extent to which newly-proposed outlier detection methods improve over established methods. In this paper, we perform an extensive experimental study on the performance of a representative set of standard k nearest neighborhood-based methods for unsupervised outlier detection, across a wide variety of datasets prepared for this purpose. Based on the overall performance of the outlier detection methods, we provide a characterization of the datasets themselves, and discuss their suitability as outlier detection benchmark sets. We also examine the most commonly-used measures for comparing the performance of different methods, and suggest adaptations that are more suitable for the evaluation of outlier detection results.     

MALDI-TOF MS: an upcoming tool for rapid detection of antibiotic resistance in microorganisms

MALDI-TOF MS profiling for microorganism detection has already been demonstrated in the 1990s, but has evolved to the first-line identification method in many laboratories just during the past five years. While this application of MALDI-TOF MS has proven its broad applicability, accuracy, robustness, and cost-effectiveness it is of particular interest to expand the capabilities of the mass spectrometric platform. Resistance detection is the most desirable further application of MALDI-TOF MS in microbiology, but maybe also the most challenging. Different approaches have been published regarding diverse antibiotic drugs and distinct microorganism classes. The current review shall give an overview about the developments of the recent years and their potential to get transformed in clinical useful assays in the future.