63 research outputs found
Estimation of Nonlinear ARX Model for Soft Tissue by Wavenet and Sigmoid Estimators
This paper presents a model-based design technique to estimate the dynamic model of a nonlinear soft tissue phantom using MATLAB Simulink. The soft tissue model was developed using black-box modeling approach; simulations were performed based on acquired set of single input-output data and processed using MATLAB System Identification toolbox. Wavenet and sigmoid estimators were used to acquire the best overall performance. Comparison study has been made between the simulation and experimental results. Our finding shows that the obtained model is sufficient to represent the model of soft tissue phantom with a mean error of 4.12% compared to the real system
Supramolecular interactions in aromatic structures for non-optical and optical chemosensors of explosive chemicals
The scientific investigation based on the molecular design of aromatic compounds for high-performance chemosensor is challenging. This is because their multiplex interactions at the molecular level should be precisely determined before the desired compounds can be successfully used as sensing materials. Herein, we report on the molecular design of chemosensors based on aromatic structures of benzene as the organic motif of benzene-1,3,5-tricarboxamides (BTA), as well as the benzene pyrazole complexes (BPz) side chain, respectively. In the case of BTA, the aromatic benzene acts as the centre to allow the formation of π–π stacking for one-dimensional materials having rod-like arrangements that are stabilized by threefold hydrogen bonding. We found that when nitrate was applied, the rod-like BTA spontaneously formed into a random aggregate due to the deformation of its hydrogen bonding to form inactive nitroso groups for non-optical sensing capability. For the optical chemosensor, the aromatic benzene is decorated as a side-chain of BPz to ensure that cage-shaped molecules make maximum use of their centre providing metal-metal interactions for fluorescence-based sensing materials. In particular, when exposed to benzene, CuBPz displayed a blue-shift of its original emission band from 616 to 572 nm (Δ = 44 nm) and emitted bright orange to green emission colours. We also observe a different mode of fluorescencebased sensing materials for Au-BPz, which shows a particular quenching mechanism resulting in 81% loss of its original intensity on benzene exposure to give less red-orange emission (λ = 612 nm). The BTA and BPz synthesized are promising high-performance supramolecular chemosensors based on the non-optical and optical sensing capability of a particular interest analyte
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Improvement of Aqueous Solubility of Lapatinib-Derived Analogues: Identification of a Quinolinimine Lead for Human African Trypanosomiasis Drug Development
Lapatinib, an approved epidermal growth factor receptor inhibitor, was explored as a starting point for the synthesis of new hits against Trypanosoma brucei, the causative agent of human African trypanosomiasis (HAT). Previous work culminated in 1 (NEU-1953), which was part of a series typically associated with poor aqueous solubility. In this report, we present various medicinal chemistry strategies that were used to increase the aqueous solubility and improve the physicochemical profile without sacrificing antitrypanosomal potency. To rank trypanocidal hits, a new assay (summarized in a cytocidal effective concentration (CEC50)) was established, as part of the lead selection process. Increasing the sp3 carbon content of 1 resulted in 10e (0.19 μM EC50 against T. brucei and 990 μM aqueous solubility). Further chemical exploration of 10e yielded 22a, a trypanocidal quinolinimine (EC50: 0.013 μM; aqueous solubility: 880 μM; and CEC50: 0.18 μM). Compound 22a reduced parasitemia 109 fold in trypanosome-infected mice; it is an advanced lead for HAT drug development
A transient self-assembling self-replicator
Developing physical models of complex dynamic systems showing emergent behaviour is key to informing on persistence and replication in biology, how living matter emerges from chemistry, and how to design systems with new properties. Herein we report a fully synthetic small molecule system in which a surfactant replicator is formed from two phase-separated reactants using an alkene metathesis catalyst. The replicator self-assembles into aggregates, which catalyse their own formation, and is thermodynamically unstable. Rather than replicating until the reactants are fully consumed, the metastable replicator is depleted in a second metathesis reaction, and closed system equilibrium is eventually reached. Mechanistic experiments suggest phase separation is responsible for both replicator formation and destructio
NMR and Pulsed Field Gradient NMR Approach of Water Sorption Properties in Nafion at Low Temperature
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