Responsive Inverse Opal Hydrogels for the Sensing of Macromolecules

Dual responsive inverse opal hydrogels were designed as autonomous sensor systems for (bio)macromolecules, exploiting the analyte‐induced modulation of the opal’s structural color. The systems that are based on oligo(ethylene glycol) macromonomers additionally incorporate comonomers with various recognition units. They combine a coil‐to‐globule collapse transition of the LCST type with sensitivity of the transition temperature toward molecular recognition processes. This enables the specific detection of macromolecular analytes, such as glycopolymers and proteins, by simple optical methods. While the inverse opal structure assists the effective diffusion even of large analytes into the photonic crystal, the stimulus responsiveness gives rise to strong shifts of the optical Bragg peak of more than 100 nm upon analyte binding at a given temperature. The systems’ design provides a versatile platform for the development of easy‐to‐use, fast, and low‐cost sensors for pathogens.     

One-parameter orthogonality relations for basic hypergeometric series

The second order hypergeometric q-difference operator is studied for the value c = −q. For certain parameter regimes the corresponding recurrence relation can be related to a symmetric operator on the Hilbert space ℓ²( ). The operator has deficiency indices (1, 1) and we describe as explicitly as possible the spectral resolutions of the self-adjoint extensions. This gives rise to one-parameter orthogonality relations for sums of two ₂₁-series. In particular, we find that the Ismail-Zhang q-analogue of the exponential function satisfies certain orthogonality relations.     

Intraventricular dispersion and temporal delay of early left ventricular filling after acute myocardial infarction. Assessment by magnetic resonance velocity mapping

This article aims to describe early left ventricular diastolic inflow using magnetic resonance velocity mapping in patients with recent acute myocardial infarction and in normal volunteers. Magnetic resonance velocity mapping was performed in a long axis plane through the hearts of 46 patients with recent, first time acute myocardial infarction and 43 age-matched normal volunteers. The peak velocities at six levels of the early diastolic inflow stream were recorded. A velocity index was calculated as the peak velocity in each position relative to the peak velocity at the mitral leaflet tips. Also, the temporal delay of velocity propagation was computed. Velocity index 4 cm downstream of mitral leaflet tips was lower in the acute myocardial infarction group (0.42 (0.17)) (mean (SD)) compared to controls (0.59 (0.25)) (p < 0.001). Temporal delay in the same position was longer in the acute myocardial infarction group (62 (67) ms) than in controls (32 (39) ms) (p < 0.02). Blood flow patterns in patients after acute myocardial infarction were characterized by increased dispersion of velocities and increased temporal delay of velocity propagation, probably reflecting impaired active left ventricular relaxation. Intraventricular flow measurements constitute a promising new technique for non-invasive assessment of left ventricular diastolic function.     

Three-dimensional phase contrast velocity mapping acquisition improves wall shear stress estimation in vivo

The purpose of this study was to evaluate and apply high-resolution three-dimensional phase contrast mapping for estimation of wall shear stress in vivo. A silicon pipe of 8 mm diameter with a 8.3 ml/s steady flow and the entrance of the carotid bifurcation in 10 young healthy volunteers aged 23.6 +/- 3.1 years was studied. Very high resolution three-dimensional and two-dimensional phase contrast mapping sequences with spatial resolutions of 0.31 x 0.31 x 1.5 mm(3) and 0.31 x 0.31 x 3 mm(3), respectively, were compared in vivo and in vitro. Wall shear stress was calculated using multi-sectored, three-dimensional paraboloid fitting. In comparison to the two-dimensional measurements, the three-dimensional method with only half the slice thickness gave higher signal-to-noise ratio and velocity-to-noise ratios both in vivo and in vitro. Wall shear stress derived from the three-dimensional velocity measurements did not differ from the two-dimensional velocity measurements either in vitro or in vivo. Mean wall shear stress was lowest and oscillatory shear index was highest at the outer wall, towards the carotid bifurcation. Three-dimensional velocity mapping increases resolution and image quality and allows estimation of wall shear stress patterns circumferentially and longitudinally in human arteries.     

Numerical Simulation of Non-premixed Turbulent Combustion Using the Eddy Dissipation Concept and Comparing with the Steady Laminar Flamelet Model

Numerical simulations of the Sandia flame CHNa and the Sydney bluff-body stabilized flame HM1E are reported and the results are compared to available experimental data. The numerical method is based on compressible URANS formulations which were implemented recently in the OpenFOAM toolbox. In this study, the calculations are carried out using the conventional compressible URANS approach and a standard k- ?? turbulence model. The Eddy Dissipation Concept with a detailed chemistry approach is used for the turbulence-chemistry interaction. The syngas (CO/H₂) chemistry diluted by 30 % nitrogen in the Sandia flame CHNa and CH₄/H₂ combustion in the Sydney flame HM1E are described by the full GRI-3.0 mechanism. A robust implicit Runge-Kutta method (RADAU5) is used for integrating stiff ordinary differential equations to calculate the reaction rates. The radiation is treated by the P1-approximation model. Both target flames are predicted with the Steady Laminar Flamelet model using the commercial code ANSYS FLUENT as well. In general, there is good agreement between present simulations and measurements for both flames, which indicates that the proposed numerical method is suitable for this type of combustion, provides acceptable accuracy and is ready for further combustion application development.     

First real-time measurement of the evolving 2H/1H ratio during water evaporation from plant leaves

We have studied the temporal behaviour of the deuterium isotope ratio of water vapour emerging from a freshly cut plant leaf placed in a dry nitrogen atmosphere. The leaf material was placed directly inside the sample gas cell of the stable isotope ratio infrared spectrometer. At the reduced pressure (～40 mbar) inside the cell, the appearance of water evaporating from the leaf is easily probed by the spectrometer, as well as the evolving isotope ratios, with a precision of about 1 ‰. The demonstration experiment we describe measures the ²H/¹H isotope ratio only, but the experiment can be easily extended to include the ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotope ratios. Plant leaf water isotope ratios provide important information towards quantification of the different components in the ecosystem water and carbon dioxide exchange.     

Measuring δ13C of atmospheric air with non-dispersive infrared spectroscopy

The potential use of non-dispersive infrared spectroscopy for measuring δ¹³C in air is demonstrated. This technique has already been successfully established for breath test analyses in medical diagnostics, where the CO₂ concentration ranges from 1 to 5 vol.% in the exhaled breath of vertebrates. For breath tests, the sensitivity and accuracy has been improved to reach a standard deviation of 0.2 ‰ (delta-value). Further adjustments were necessary to improve the sensitivity of the instrument at concentration levels typical of atmospheric air. The long-term stability is given by a standard deviation of 0.35 ‰ for CO₂ concentrations of about 400 ppm with signal averaging over 60 s.     

Use of a tandem Prins/Friedel-Crafts reaction in the construction of the indeno-tetrahydropyridine core of the haouamine alkaloids: formal synthesis of (-)-haouamine A

A tandem Prins/Friedel-Crafts reaction useful for the construction of the indeno-tetrahydropyridine core of the haouamine alkaloids and a formal synthesis of (-)-haouamine A are described.     

Prototropic processes in benzaurins. <Superscript>19</Superscript>F and <Superscript>1</Superscript>H NMR spectra of fluoro- and methylsubstituted 4-hydroxyphenyl-diphenylcarbinols,related fuchsones and benzaurins

Tautomerism of benzaurins and hydration are studied. ¹H and ¹⁹F chemical shifts have been determined for a number of substituted 4-hydroxyphenyl-diphenyl carbinols containing fluorine in a 3-, 3*- or 4*-position, and for similar compounds containing additional methyl groups in a position of 3, 3** or 4**. The same data have been obtained for the fuchsones prepared by dehydration of the above carbinols. On this basis chemical shifts of fluorine in different positions have been evaluated as a monitor of the transformation of 4-hydroxyphenyl group to the semiquinone moiety. The ¹⁹F NMR can be used to monitor the transformation of 4**-fluorobenzaurin and the related 3,3*-disubstituted and 3,3*,5,5*-tetramethylsubstituted compounds to the corresponding carbinols due to the addition of a water molecule and to study the tautomerism of the two latter benzaurins as well as that of 3,3*,4**trifluorobenzaurin. Furthermore, fluorine and methyl group chemical shifts are sensitive to syn-anti-isomerism in substituted fuchsones.     

Chemical composition and antioxidant activities of the essential oil from Tornabenea bischoffii (Apiaceae)

The chemical composition of Tornabenea bischoffii J. A. Schmidt essential oil from Cape Verde was studied by GC and GC/MS. Sixty volatile compounds were identified of which myristicin was the major constituent (33.6%). Using the 2,2-diphenyl-2-picrylhydrazyl free-radical scavenging method and the in vitro assay for prevention of lipid peroxidation by thiobarbituric reactive species, significant antioxidant activities were evidenced.