Scanning probe microscopy (SPM) techniques have become indispensable tools for studying nano- and microscale materials and processes but suffer from a trade-off between resolution and areal scan rate that limits their utility for a number of applications and sample types. Here, we present a novel approach to SPM imaging based on combining nonlocal scanning line probes with compressed sensing (CS) signal analysis methods. Using scanning electrochemical microscopy (SECM) as an exemplar SPM technique, we demonstrate this approach using continuous microband electrodes, or line probes, which are used to perform chemical imaging of electrocatalytic Pt discs deposited on an inert substrate. These results demonstrate the potential to achieve high areal SPM imaging rates using nonlocal scanning probes and CS image reconstruction.
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http://dx.doi.org/10.1021/acs.analchem.8b02852 | DOI Listing |
ACS Appl Bio Mater
January 2025
Department of Chemistry, Indian Institute of Technology Palakkad, Palakkad, Kerala 678 623, India.
The aggregation of proteins, peptides and amino acids has been a keen subject of interest owing to their implications in metabolic disorders. In this work, we investigated the self-aggregation of the unmodified aromatic amino acid l-tryptophan (Trp) into unusual spherical microstructures. Using fluorescence spectroscopy and field emission scanning electron microscopy (FE-SEM), we detail the time-dependent transformation of monomeric tryptophan into spherical aggregates with distinct fluorescence characteristics (λ = 345 nm, λ = 430 nm) compared to the monomer.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Institute of Physics, NAWI Graz, University of Graz, Universitätsplatz 5, 8010 Graz, Austria.
For weakly interacting adsorbate/substrate systems, the integer charge transfer (ICT) model describes how charge transfer across interfaces depends on the substrate work function. In particular, work function regimes where no charge transfer occurs (vacuum level alignment) can be distinguished from regions where integer charge transfer by electron tunneling from substrate to adsorbate or vice versa takes place (Fermi level pinning). While the formation of singly integer charged molecular anions and cations of organic semiconductors on various substrates has been well described by this model, the double integer charging regime has so far remained unexplored and experimentally elusive.
View Article and Find Full Text PDFQuant Imaging Med Surg
January 2025
Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Background: Rapid eye movement sleep behavior disorder (RBD) is associated with pathological α-synuclein deposition and may have different damage directions due to α-synuclein spreading orientations. Recent functional imaging studies of Parkinson's disease (PD) with RBD have identified abnormalities in connectivity, but effective connectivity (EC) for this altered orientation is understudied. Here, we aimed to explore altered intrinsic functional connectivity (FC) and EC in PD patients with probable RBD (pRBD).
View Article and Find Full Text PDFQuant Imaging Med Surg
January 2025
Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Background: Magnetic resonance (MR) diffusion-derived 'vessel density' (DDVD) is calculated according to: DDVD = Sb0/ROI - S/ROI, where S and S refer to the tissue signal when -value is 0 or 2 s/mm. S and ROI can also be approximated by other low -values diffusion-weighted imaging (DWI). This study investigates the influence of the second motion probing gradient -value and T2 on DDVD calculations of the liver, spleen, and liver simple cyst.
View Article and Find Full Text PDFSmall
January 2025
Leibniz-Institut für Polymerforschung e. V, Hohe Str. 6, 01069, Dresden, Germany.
Polyelectrolyte brushes (PEBs) undergo conformational transitions due to changes in pH and/or ionic strength, which is leveraged as smart surfaces and on-demand drug-release systems. However, probing conformational transitions of functional PEBs has remained challenging due to low spatiotemporal resolution of characterization methods. Herein, fluorescently-coupled PEBs are devised that give rise to Förster Resonance Energy Transfer (FRET) intrinsically coupled to conformational transitions of chains.
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