XNOR-Nets with SETs: Proposal for a binarised convolution processing elements with Single-Electron Transistors.

Deep neural network (DNN) and Convolution neural network (CNN) algorithms have significantly increased the accuracies in cutting-edge large-scale image recognition and natural-language processing tasks. Generally, such neural nets are implemented on power-hungry GPUs, beyond the reach of low-power edge-devices. The binary neural nets have been proposed recently, where both the input activations and weights are constrained to [Formula: see text] 1 and - 1 to address this challenge. Here in the present proof-of-concept study, we propose a simple class of mixed-signal circuits composed of single-electron devices and exploit the nonlinear Coulomb staircase phenomena to alleviate the challenges of binarised deep learning hardware accelerators. In particular, through SPICE modeling, we demonstrate the realisation of space-time-energy efficient XNOR-Accumulation (XAC) operation, reconfigurabilty of XAC circuit to perform 1D convolution and a busbar design to augment a contemporary accelerator. These nanoscale circuits could be readily fabricated and may potentially be deployed in low-power deep-learning systems.

Mimicking the Energy Funnel of the Photosynthetic Unit Using a Dendrimer-Dye Supramolecular Assembly.

Photosynthesis involves light-harvesting complexes where an array of antenna pigment channels the absorbed solar energy to the reaction centre of a photosystem. This work reports a supramolecular dendrimer-dye assembly that mimics the natural light-harvesting mechanism. A dendrimeric molecule based on two-fluorophores has been constructed with three coumarin units at the end of three long arms and a 7-diethylaminocoumarin unit at the interior. The molecule self-aggregates in water into spherical micelles, which can encapsulate a rose-bengal dye (RB). On excitation, peripheral coumarin units shuttled the energy to the loaded RB dye reaction center via a two-step cascade resonance energy transfer (RET). The energy absorbed in the periphery is funnelled efficiently, resulting in a strong emission from the dye that resembles an energy funnel. The energy transfer cascade has been studied with both steady-state and time-resolved fluorescence spectroscopy. Molecular dynamics simulations of the self-assembled aggregates in water were also in agreement with the experimental observations.

Photomodulation of fluoride ion binding through anion-π interactions using a photoswitchable azobenzene system.

The discovery of photoswitchable azobenzene-systems that undergo trans-to-cis photoisomerisation was a milestone in supramolecular chemistry. Such photoswitches have possible applications in data storage, stimuli responsive delivery systems, and molecular machines due to fast and selective switching. However, the light induced cis isomer of azobenzene is rather unstable and reverts thermally and photochemically to the thermodynamically stable trans configuration. We report, for the first time, controlled photoswitching of an azo-naphthalenediimide (azo-NDI) which can be achieved upon binding of fluoride ions through anion-π interaction. This NDI-F-NDI "sandwich" stabilises the cis configuration through the generation of an NDI(•-) radical anion, and a dianionic, NDI(2-) species that becomes unusually stable in the cis form. The sandwiched cis form reverts to the trans form only upon decomplexation of F(-). A model pollutant was successfully degraded using the photogenerated NDI-F-NDI sandwich. This opens a wide range of applications in molecular and supramolecular nanotechnology.

Aß17-20 Peptide-Guided Structuring of Polymeric Conjugates and Their pH-Triggered Dynamic Response.

The tetrapeptide segment LVFF from the central hydrophobic core of amyloid ß-peptide, Aß17-20 , based methacrylate monomer was polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization to afford well-defined side-chain peptide polymers. The polymer was transformed to carry primary amino groups in the peptide terminals, depicting pH-responsiveness and was further modified to provide amphiphilic graft copolymer-based nanocarriers with pH-triggered dynamic dye release capability. The polymers acquired α-helical conformation guided by Aß17-20 peptide. Computational studies were performed to investigate the secondary interactions of the peptide-based materials.