Directed molecular repositioning is a key step toward the build up of molecular machines. To artificially generate and control the motion of molecules on a surface, excitations by light, chemical, or electrical energy have been demonstrated. Here, the application of local mechanical forces is implemented to achieve directed rotations of molecules. Three-dimensional force spectroscopy with sub-Ångström precision is used to characterize porphyrin derivatives with peripheral carbonitrile groups. Extremely small areas on these molecules (≈ 100 × 100 pm(2)) are revealed which can be used to control rotations. In response to the local mechanical forces, the molecular structure elastically deforms and then changes its conformation, which leads to its rotation. Depending on the selection of one of four submolecular areas, the molecule is either rotated clockwise or counterclockwise.
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http://dx.doi.org/10.1021/nn301774d | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
Recent photolysis experiments with formic acid suggest that the roaming mechanism is a significant CO-forming pathway at a photolysis energy of 230 nm. While previous computational studies have identified multiple dissociation pathways for CO-forming channels, the dynamic features of these pathways remain poorly understood. This study investigates the dissociation dynamics of the CO + HO and CO + H channels in the ground state (S) of formic acid using direct dynamics simulation and the generalized multi-center impulsive model (GMCIM) at 230 nm.
View Article and Find Full Text PDFJ Brachial Plex Peripher Nerve Inj
January 2025
Integrative Neuromedicine, Community Hospital Herdecke, Witten/Herdecke University, Herdecke, Germany.
To date, there are no uniform guidelines for the treatment of obstetric plexus lesions in German-speaking countries. An end-to-end direct suture after resection of trunk neuroma is recommended for surgical treatment if tension-free coaptation is possible, whereas the use of autologous nerve grafts bridging the gap between the adaptation margins is advised by consensus if tension-free coaptation is impossible. The aim of the study was to investigate which reconstruction strategy may provide a better recovery of motor function for patients after obstetric brachial plexus lesion.
View Article and Find Full Text PDFLangmuir
January 2025
College of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China.
Porous nanomaterials have shown great promise in many desalination applications. Zeolite nanotubes, featuring abundant but inhomogeneous nanopores on their surface, have been recently synthesized in experiments; however, their capacity for desalination is not yet understood. In this work, we use molecular dynamics simulations to investigate the capability of assembled zeolite nanotube membranes to perform in desalination applications due to their inherent multiscale porous properties.
View Article and Find Full Text PDFWe introduce a novel, to the best of our knowledge, method to achieve a highly efficient nonreciprocal magnon laser within a spinning cavity optomagnonic system, which integrates a magnon mode and two optical modes. The rotation of the YIG sphere triggers the Barnett effect in the magnon mode and the Sagnac effect in the optical modes. The directional input of a pump light leads to opposite Sagnac-Fizeau frequency shifts in these modes.
View Article and Find Full Text PDFThis Letter introduces a method for identifying the fast axis and phase retardation of wave plates by means of polarization common-path vortex interferometry. The technique utilizes a composite polarized vortex beam interacting with the wave plate under test. By analyzing the azimuth angle of the dark fringe in the interference pattern, the wave plate's characteristics are accurately extracted.
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