Layered assembly of cationic and anionic supramolecular polymers

The chemical synthesis and the supramolecular assembly of an aromatic oligoamine are described. The self-assembly of the cationic oligomers in aqueous solution leads to the formation of vesicular objects. The assembly process of the oligomers is monitored by absorption and fluorescence spectroscopy and the formed vesicles are characterized by atomic force and transmission electron microscopy. The electrostatic complementarity of anionic supramolecular polymers sheets and the cationic vesicles is used for a layered assembly process

Pyrene-DNA Conjugates: Influence of sticky Ends on the Supramolecular Self-Assembly

The supramolecular assembly of DNA conjugates has caught attention in supramolecular chemistry. DNA bears some unique features enabling the design of complex nanostructures. The DNA framework offers a defined spatial arrangement of modifications. In preceding work DNA was modified with phenanthrene at the 3’-ends of DNA forming vesicular supramolecular assemblies with unique light-harvesting properties.[1] Interestingly, the modification of DNA with E-tetraphenylethylenes sticky ends led to aggregation-induced emission (AIE) active assemblies.[2] In this work, we modified a DNA strand at the 3’- and 5’-end with 1,6-pyrene (Figure 1A). We varied the length of the sticky ends to compare their self-assembly properties (1, 2, and 3 pyrene units on either side). For example, AFM measurements of the 1,6-pyrene-DNA conjugates with a total of 6 pyrene units revealed their self-assembly into vesicles (Figure 1B). In addition to AFM studies, fluorescence and UV-vis spectroscopy measurements will be presented and discussed

A comparison of the Bravyi-Kitaev and Jordan-Wigner transformations for the quantum simulation of quantum chemistry

The ability to perform classically intractable electronic structure calculations is often cited as one of the principal applications of quantum computing. A great deal of theoretical algorithmic development has been performed in support of this goal. Most techniques require a scheme for mapping electronic states and operations to states of and operations upon qubits. The two most commonly used techniques for this are the Jordan-Wigner transformation and the Bravyi-Kitaev transformation. However, comparisons of these schemes have previously been limited to individual small molecules. In this paper we discuss resource implications for the use of the Bravyi-Kitaev mapping scheme, specifically with regard to the number of quantum gates required for simulation. We consider both small systems which may be simulatable on near-future quantum devices, and systems sufficiently large for classical simulation to be intractable. We use 86 molecular systems to demonstrate that the use of the Bravyi-Kitaev transformation is typically at least approximately as efficient as the canonical Jordan-Wigner transformation, and results in substantially reduced gate count estimates when performing limited circuit optimisations.Comment: 46 pages, 11 figure

Development of tsunami early warning systems and future challenges

Fostered by and embedded in the general development of information and communications technology (ICT), the evolution of tsunami warning systems (TWS) shows a significant development from seismic-centred to multi-sensor system architectures using additional sensors (e.g. tide gauges and buoys) for the detection of tsunami waves in the ocean. <br><br> Currently, the beginning implementation of regional tsunami warning infrastructures indicates a new phase in the development of TWS. A new generation of TWS should not only be able to realise multi-sensor monitoring for tsunami detection. Moreover, these systems have to be capable to form a collaborative communication infrastructure of distributed tsunami warning systems in order to implement regional, ocean-wide monitoring and warning strategies. <br><br> In the context of the development of the German Indonesian Tsunami Early Warning System (GITEWS) and in the EU-funded FP6 project Distant Early Warning System (DEWS), a service platform for both sensor integration and warning dissemination has been newly developed and demonstrated. In particular, standards of the Open Geospatial Consortium (OGC) and the Organization for the Advancement of Structured Information Standards (OASIS) have been successfully incorporated. <br><br> In the FP7 project Collaborative, Complex and Critical Decision-Support in Evolving Crises (TRIDEC), new developments in ICT (e.g. complex event processing (CEP) and event-driven architecture (EDA)) are used to extend the existing platform to realise a component-based technology framework for building distributed tsunami warning systems

Tetraphenylethylene–DNA conjugates: influence of sticky ends and DNA sequence length on the supramolecular assembly of AIE-active vesicles

The supramolecular assembly of DNA conjugates, functionalized with tetraphenylethylene (TPE) sticky ends, into vesicular structures is described. The aggregation-induced emission (AIE) active TPE units allow to monitor the assembly process by fluorescence spectroscopy. The number of TPE modifications in the overhangs of the conjugates influences the supramolecular assembly behavior. A minimum of two TPE residues on each end are required to ensure a well-defined assembly process. The design of the presented DNA-based nanostructures offers tailored functionalization with applications in DNA nanotechnology

Supramolecular Assembly of Pyrene-DNA Conjugates into Columnar Vesicles

This poster describes the supramolecular assembly of DNA conjugates functionalized with pyrene sticky-ends. After hybridization, the 3’-end modified DNA single strands self-assembled into vesicles with diameters of 50–200 nm. Columnar packed aggregated and multilamellar vesicles were observed by cryo-EM

Supramolecular assembly of pyrene-DNA conjugates: influence of pyrene substitution pattern and implications for artificial LHCs.

The supramolecular self-assembly of pyrene-DNA conjugates into nanostructures is presented. DNA functionalized with different types of pyrene isomers at the 3'-end self-assemble into nano-objects. The shape of the nanostructures is influenced by the type of pyrene isomer appended to the DNA. Multilamellar vesicles are observed with the 1,6- and 1,8-isomers, whereas conjugates of the 2,7-isomer exclusively assemble into spherical nanoparticles. Self-assembled nano-spheres obtained with the 2,7-dialkynyl pyrene isomer were used for the construction of an artificial light-harvesting complex (LHC) in combination with Cy3 as the energy acceptor

Amphiphilic anthanthrene trimers that exfoliate graphite and individualize single wall carbon nanotubes

A phosphodiester-linked dialkynyl substituted anthanthrene trimer (1) has been designed and synthesized. Its graphene ribbon like structure is expected to facilitate interactions with nanographene (NG) and single wall carbon nanotubes (SWCNT) to yield novel and stable carbon-based nanomaterials. Interactions with trimer 1 leads to exfoliation of NG and to the individualization of SWCNTs. Phosphate groups, in general, and their negative charges, in particular, render the resulting nanomaterials soluble in ethanol, which is ecologically favourable over DMF required for the processing of pristine NG or SWCNTs. The newly formed nanomaterials were probed by complementary spectroscopic and microscopic techniques. Of particular importance were transient absorption fluorescence excitation measurements, which revealed an efficient energy transfer within the carbon-based nanomaterials