Camphor-derived sulfonylhydrazines: catalysts for Diels-Alder cycloadditions

Camphor-derived sulfonylhydrazines proved to be very active for organocatalyzed Diels-Alder cycloadditions with cyclopentadiene. Good chemical yields and enantiomeric excesses up to 89% and 88% are obtained for endo/exo adducts.     

Effective dissipation and turbulence in spectrally truncated euler flows

A new transient regime in the relaxation towards absolute equilibrium of the conservative and time-reversible 3D Euler equation with a high-wave-number spectral truncation is characterized. Large-scale dissipative effects, caused by the thermalized modes that spontaneously appear between a transition wave number and the maximum wave number, are calculated using fluctuation dissipation relations. The large-scale dynamics is found to be similar to that of high-Reynolds number Navier-Stokes equations and thus obeys (at least approximately) Kolmogorov scaling.     

Investigation of the rh-catalyzed asymmetric reductive aldol reaction. Expanded scope based on reaction analysis

[reaction: see text] A series of experiments are described that suggest that the Rh-catalyzed reductive aldol reaction proceeds by addition of a Rh(I) hydride, generated in situ, to the reacting acrylate followed by a stereochemistry-controlling aldol addition reaction. On the basis of this hypothesis, reaction conditions are engineered that allow for increased substrate scope.     

Absorbing boundary conditions for the two-dimensional Schrödinger equation with an exterior potential

Four families of ABCs where built in Antoine et al. (Math Models Methods Appl Sci, 22(10), 2012) for the two-dimensional linear Schrödinger equation with time and space dependent potentials and for general smooth convex fictitious surfaces. The aim of this paper is to propose some suitable discretization schemes of these ABCs and to prove some semi-discrete stability results. Furthermore, the full numerical discretization of the corresponding initial boundary value problems is considered and simulations are provided to compare the accuracy of the different ABCs.     

Chondroitin Sulfate and Epidermal Growth Factor Immobilization after Plasma Polymerization: A Versatile Anti‐Apoptotic Coating to Promote Healing Around Stent Grafts

Bioactive coatings constitute an interesting approach to enhance healing around implants, such as stent‐grafts used in endovascular aneurysm repair. Three different plasma techniques, namely NH₃ plasma functionalization and atmospheric‐ or low‐pressure plasma polymerization, are compared to create amino groups and covalently bind CS and EGF bioactive molecules on PET. The latter presents the greatest potential. CS + EGF coating is shown to strongly decrease cell apoptosis and cell depletion in serum‐free medium, while increasing cell growth compared to unmodified PET. This versatile biomimetic coating holds promise in promoting vascular repair around stent‐grafts, where resistance to apoptosis is a key issue.

     

A 3D balanced-SSFP Dixon technique with group-encoded k-space segmentation for breath-held non-contrast-enhanced MR angiography

A three-dimensional balanced steady-state free precession (b-SSFP)-Dixon technique with a novel group-encoded k-space segmentation scheme called GUINNESS (Group-encoded Ungated Inversion Nulling for Non-contrast Enhancement in the Steady State) was developed. GUINNESS was evaluated for breath-held non-contrast-enhanced MR angiography of the renal arteries on 18 subjects (6 healthy volunteers, 12 patients) at 3.0 T. The method provided high signal-to-noise and contrast renal angiograms with homogeneous fat and background suppression in short breath-holds on the order of 20 s with high spatial resolution and coverage. GUINNESS has potential as a short breath-hold alternative to conventional respiratory-gated methods, which are often suboptimal in pediatric subjects and patients with significant diaphragmatic drift/sleep apnea.     

Optimized methods for preparing activated carbon from rock asphalt using orthogonal experimental design

Journal of Thermal Analysis and Calorimetry - This work evaluated three activation methods, physical activation, chemical activation and combined physical–chemical activation, for preparing...     

High throughput plasma N-glycome profiling using multiplexed labelling and UPLC with fluorescence detection

A rapid glycomic profiling method is described wherein N-glycans from plasma samples individually labelled with aniline, 2-aminobenzamide and 2-aminoacridone are mixed, co-injected and separated in the same HILIC-fluorescence run. Transfer of the multiplexed method to UPLC-fluorescence permits an increase in sample throughput from 24 to 864 plasma samples per day.     

Zur Darstellung des Protocatechualdehyds und des Vanillins

Ohne Zusammenfassung     

Dynamic octopus amphiphiles as powerful activators of DNA transporters: differential fragrance sensing and beyond

We report the design, synthesis and evaluation of dynamic "octopus" amphiphiles with emphasis on their efficiency as activators in synthetic membrane-based sensing systems. Previously, we found that the in situ treatment of charged hydrazides with hydrophobic aldehydes or ketones gives amphiphilic counterion activators of polyion transporters in lipid bilayers, and that their efficiency increases with the number of their hydrophobic tails. Herein, we expand this series to amphiphiles with one cationic head (guanidinium or ammonium) and four exchangeable hydrophobic tails. These results, with the highest number of tails reported to date, confirm that dynamic octopus amphiphiles provide access to maximal activity and selectivity. Odorants, such as muscone, carvone, or anisaldehyde are used to outline their usefulness in differential sensing systems that operate based on counterion-activated DNA transporters in fluorogenic vesicles. The enhanced ability of octopus amphiphiles to enable the discrimination of enantiomers as well as that of otherwise intractable ortho, meta, and para isomers and short cyclo-/alkyl tails is demonstrated. These findings identify dynamic octopus amphiphiles as being promising for application to differential sensing, "fragrant" cellular uptake, and slow release.