π Groups in ion pair bonding: the structural effects of reduction on the olefinic bond as observed in the molecular structure of Δ9,9′-bifluorenyl bis(lithium tetramethylethylenediamine)

The reaction of 9,9′-bifluorene with n-butyllithium in the presence of tetramethylethylenediamine (TMEDA) results in the formation of Δ^9,9′-bifluorenyl bis-(lithium tetramethylethylenediamine). In the molecular structure of this material, which formally can be considered to be the dianion of the olefin Δ^9,9′-bifluorene, two TMEDALi groups are closely associated with the 9,9′ bond. The fluorenyl groups are twisted relative to each other by an angle of 48.0(5)°, as compared to 42° in the parent olefin. The 9,9′ bond length is increased from 1.39(2) Å in Δ^9,9′-bifluorene to 1.487(5)Å in the dianion.Single crystal X-ray diffraction techniques were used and resulted in a final discrepancy factor of R_w = 0.064 for 2426 observations. The crystal system is monoclinic (C2/c) with a = 10.814(3), b = 16.717(6) and c = 19.766(6) Å, β = 102.55(2)°; ?_obs = 1.10(3) g cm^?3; ?_calc = 1.095 g cm^?3 for four molecules per unit cell.     

Influence of metal ions on the 44Sc-labeling of DOTATATE

Journal of Radioanalytical and Nuclear Chemistry - The aim of the study was to evaluate the labeling yield of 44Sc-DOTATATE radiobioconjugate when the labeling is performed in the presence of...     

Solving Nonlinear p-Adic Pseudo-differential Equations: Combining the Wavelet Basis with the Schauder Fixed Point Theorem

We consider the pointwise convergence problem for the solution of Schrödinger-type equations along directions determined by a given compact subset of the real line. This problem contains Carleson’s problem as the simplest case and was studied in general by Cho et al. We extend their result from the case of the classical Schrödinger equation to a class of equations which includes the fractional Schrödinger equations. To achieve this, we significantly simplify their proof by completely avoiding a time localization argument.     

Validation of temperature-controlled rheo-MRI measurements in a submillimeter-gap Couette geometry

A temperature-controlled submillimeter-gap (500 μm) rheo-magnetic resonance imaging (MRI) Couette cell has been developed to measure confined flow of soft structured materials under controlled temperature. The proposed setup enables performing rheo-MRI measurements using (i) a spatially uniform temperature control over the range 15°C to 40°C and (ii) a high spatial resolution up to 10 μm, as a consequence of the improved mechanical stability of the in-house developed rotating elements. Here, we demonstrate the performance of the cell for the rheo-MRI velocimetry study of a thixotropic fat crystal dispersion, a complex fluid commonly used in food manufacturing. The submillimeter-gap geometry and variable temperature capability of the cell enable observing the effects of shear- and temperature-induced fat recrystallization on both wall slip and shear banding under strongly confined flow. Our improved rheo-MRI setup opens new perspectives for the fundamental study of strongly confined flow, cooperative effects, and the underlying interparticle interactions and for ultimately aiding optimization of products involved in spreading/extrusion, such as cosmetics and foods.     

Constructing the Cubus simus and the Dodecaedron simum via paper folding

The archimedean solids Cubus simus (snub cube) and Dodecaedron simum (snub dodecahedron) cannot be constructed by ruler and compass. We explain that for general reasons their vertices can be constructed via paper folding on the faces of a cube, respectively dodecahedron, and we present explicit folding constructions. The construction of the Cubus simus is particularly elegant. We also review and prove the construction rules of the other Archimedean solids.     

Extrinsic curvatures of distributions of arbitrary codimension

In this article, using the generalized Newton transformation, we define higher order mean curvatures of distributions of arbitrary codimension and we show that they agree with the ones from Brito and Naveira [F. Brito, A.M. Naveira, Total extrinsic curvature of certain distributions on closed spaces of constant curvature, Ann. Global Anal. Geom., 18 (2000) 371–383]. We also introduce higher order mean curvature vector fields and we compute their divergence for certain distributions and using this we obtain total extrinsic mean curvatures.     

Conformational locking for band gap control in 3,4-propylenedioxythiophene based electrochromic polymers

We report a tethered poly(3,4-propylenedioxythiophene) derivative with a built-in polymer conformation restriction which locks the conjugated chain at a specific dihedral angle, thus providing a handle in which to tune the optical and electronic properties of the material.     

Determination of endothelin-1 in rats using a high-performance liquid chromatography coupled to electrospray tandem mass spectrometry

A sensitive and specific liquid chromatography tandem mass spectrometry method with electrospray ionization for the determination of endothelin-1 in rat plasma and lung effluents has been developed and validated. Detection was achieved by an Applied Biosystems MDS Sciex API 2000 triple quadrupole mass spectrometer coupled to an Agilent 1100 LC system. The limit of detection and the limit of the quantification of ET-1 in matrix buffer was estimated at 40 pM and 1 nM, respectively. The precision and accuracy for both intra- and inter-day determination of the analyte ranged from 2.5% to 14.7% and from 104.2% to 113.3%, respectively. No significant relative matrix effect was observed. Stability of ET-1 established in a bench-top, autosampler, long-term storage stability as well as freeze/thaw cycles shown no significant degradation products in the samples. The results of the method validation indicated that this method is applicable for the determination of the ET-1 concentration in an effluent from the isolated lung preparation as well as in vivo in plasma samples to evaluate ET-1 as a potential biomarker of the progression of pulmonary endothelial dysfunction and pulmonary hypertension in rats induced by a monocrotaline injection.