Publications by authors named "Stefan Wolff"

We present a novel approach to achieve spatial variations in the degree of non-covalent functionalization of twisted bilayer graphene (tBLG). The tBLG with twist angles varying between ~5° and 7° was non-covalently functionalized with 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HATCN) molecules. Our results show a correlation between the degree of functionalization and the twist angle of tBLG.

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Liquid phase exfoliation (LPE) has been used for the successful fabrication of nanosheets from a large number of van der Waals materials. While this allows to study fundamental changes of material properties' associated with reduced dimensions, it also changes the chemistry of many materials due to a significant increase of the effective surface area, often accompanied with enhanced reactivity and accelerated oxidation. To prevent material decomposition, LPE and processing in inert atmosphere have been developed, which enables the preparation of pristine nanomaterials, and to systematically study compositional changes over time for different storage conditions.

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The Amazon rainforest suffers increasing pressure from anthropogenic activities. A key aspect not fully understood is how anthropogenic atmospheric emissions within the basin interact with biogenic emissions and impact the forest's atmosphere and biosphere. We combine a high-resolution atmospheric chemical transport model with an improved emissions inventory and in-situ measurements to investigate a surprisingly high concentration of ozone (O) and secondary organic aerosol (SOA) 150-200 km downwind of Manaus city in an otherwise pristine forested region.

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Covalent functionalization of two-dimensional molybdenum disulfide (2D MoS ) holds great promise in developing robust organic-MoS hybrid structures. Herein, for the first time, we demonstrate an approach to building up a bisfunctionalized MoS hybrid structure through successively reacting activated MoS with alkyl iodide and aryl diazonium salts. This approach can be utilized to modify both colloidal and substrate supported MoS nanosheets.

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Article Synopsis
  • Antimonene, a 2D material, reacts with air to form antimonene oxide, leading to various single- and few-layer structures.
  • Using density functional theory (DFT), these structures exhibit diverse electronic properties, including behaviors as topological insulators and semiconductors, with band gaps ranging from 2.0 to 4.9 eV.
  • The study also covers the vibrational properties and Raman spectra, which can help in experimentally identifying these newly predicted structures.
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Purpose: Allodynia refers to pain evoked by physiologically innocuous stimuli. It is a disabling symptom of neuropathic pain following a lesion within the peripheral or central nervous system. In fact, two different pathophysiological mechanisms of cold allodynia (ie, hypersensitivity to innocuous cold) have been proposed.

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We propose how a fermionic quantum gas confined to an optical lattice and coupled to an optical cavity can self-organize into a state where the spontaneously emerging cavity field amplitude induces an artificial magnetic field. The fermions form either a chiral insulator or a chiral liquid carrying chiral currents. The feedback mechanism via the dynamical cavity field enables robust and fast switching in time of the chiral phases, and the cavity output can be employed for a direct nondestructive measurement of the chiral current.

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Background and Aims. Local and systemic inflammation represent a major feature of atherosclerotic cardiovascular disease (CVD) and are also linked to nonalcoholic fatty liver disease (NAFLD). Studies indicate that NAFLD might be a risk factor for CVD whereas low-to-moderate alcohol consumption is associated with lower cardiovascular morbidity and mortality compared to abstainers and heavy drinkers.

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Background And Purpose: Studies with very long follow-up are scarce in patients with cryptogenic stroke and patent foramen ovale (PFO). Little is known about the etiology of recurrent cerebrovascular events (CVE) in PFO patients.

Methods: We collected information on recurrent CVE in 308 patients with cryptogenic stroke and PFO and sought to determine concurrent stroke causes that had emerged or been newly detected since the index event.

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In spite of the fact that Helmholtz made a decisive contribution to the first principle of thermodynamics by his Erhaltung der Kraft of 1847 he did not participate actively in the following debates about the nature of heat. Probably he was cautious in some way as he did not yet belong to the community of university physicists. His research concentrated on physiology at that time.

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