We report on atomic force microscopy (AFM) in ambient and liquid environments with the qPlus sensor, a force sensor based on a quartz tuning fork with an all-electrical deflection measurement scheme. Small amplitudes, stiff sensors with bulk diamond tips and high Q values in air and liquid allow to obtain high resolution images. The noise sources in air and liquid are analyzed and compared for standard silicon cantilevers and qPlus sensors. First, epitaxial graphene was imaged in air, showing atomic steps with 3 Å height and ridges. As a second sample system, measurements on calcite (CaCO(3)) in liquids were performed in water and polyethylenglycol (PEG). We demonstrate high resolution images of steps in PEG on calcite and nanolithography processes, in particular with frequency-modulation AFM the controlled dissolution of calcite monolayers.
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http://dx.doi.org/10.1063/1.3633950 | DOI Listing |
Development
January 2025
School of Science, Technische Universität Dresden, 01062 Dresden, Germany.
The elongation of tissues and organs is important for proper morphogenesis in animal development. In Drosophila ovaries, the elongation of egg chambers involves aligned Collagen IV fiber-like structures, a gradient of extracellular matrix stiffness and actin-based protrusion-driven collective cell migration, leading to the rotation of the egg chamber. Egg chamber elongation and rotation depend on the atypical cadherin Fat2.
View Article and Find Full Text PDFThis paper explores the process of forming arrays of vertically oriented carbon nanotubes (CNTs) localized on metal electrodes using thin porous anodic alumina (PAA) on a solid substrate. On a silicon substrate, a titanium film served as the electrode layer, and an aluminium film served as the base layer in the initial film structure. A PAA template was formed from the Al film using two-step electrochemical anodizing.
View Article and Find Full Text PDFNat Commun
January 2025
Atomic and Mass Spectrometry-A&MS research unit, Department of Chemistry, Ghent University, Ghent, Belgium.
The Chicxulub asteroid impact event at the Cretaceous-Paleogene (K-Pg) boundary ~66 Myr ago is widely considered responsible for the mass extinction event leading to the demise of the non-avian dinosaurs. Short-term cooling due to massive release of climate-active agents is hypothesized to have been crucial, with S-bearing gases originating from the target rock vaporization considered an important driving force. Yet, the magnitude of the S release remains poorly constrained.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Endodontics, Faculty of Dentistry, Cukurova University, Adana, 01380, Turkey.
Objective: This in vitro study aimed to investigate the effect of five polishing systems on the surface roughness (SR) and color change (CC) of novel bulk-fill composite resins.
Methods: Fifty composite resin samples were prepared for each of the five groups: Stark Bulk Fill, SDR Plus, SonicFill 3, Charisma Bulk Flow One, and Filtek Z250. Each group of composite resins was further subdivided into five subgroups based on the polishing method applied: OptraGloss (OG), OptraGloss combined with Diapolisher paste (OG), OptiDisc (OD), OptiDisc combined with Diapolisher paste (OD), and Occlubrush (OCC) (n = 10).
J Phys Chem Lett
January 2025
Department of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom.
Atomic-scale understanding of important geochemical processes including sorption, dissolution, nucleation, and crystal growth is difficult to obtain from experimental measurements alone and would benefit from strong continuous progress in molecular simulation. To this end, we present a reactive neural network potential-based molecular dynamics approach to simulate the interaction of aqueous ions on mineral surfaces in contact with liquid water, taking Fe(II) on hematite(001) as a model system. We show that a single neural network potential predicts rate constants for water exchange for aqueous Fe(II) and for the exergonic chemisorption of aqueous Fe(II) on hematite(001) in good agreement with experimental observations.
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