1,118 results match your criteria: "Universitat Kaiserslautern[Affiliation]"

Iron-sulfur (Fe-S) clusters are prosthetic groups of proteins biosynthesized on scaffold proteins by highly conserved multi-protein machineries. Biosynthesis of Fe-S clusters into the ISCU scaffold protein is initiated by ferrous iron insertion, followed by sulfur acquisition, via a still elusive mechanism. Notably, whether iron initially binds to the ISCU cysteine-rich assembly site or to a cysteine-less auxiliary site via N/O ligands remains unclear.

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Ultrasonic processes such as ultrasonic welding or ultrasonic fatigue testing use power ultrasound to stimulate materials with amplitudes in the range of 1-100 µm. The ultrasonic welding process is sensitive to any changes in the system or even the environment that may result in lower joint quality. The welding tools, so called sonotrodes, have to be accurately designed to endure high mechanical and thermal loads while inducing a sufficient amount of welding energy into the joining zone by oscillation with the Eigenfrequency of the whole system.

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We have studied activation of the methyl C-H bonds in the cyclopentadienyl ligands of half-sandwich Rh(III) complexes [-CpRh(N,N')Cl] by observing the dependence of sequential H/D exchange on variations in Cp = Cp* (complexes 1 and 2), MePhCp (Cp, 3) or MePhPhCp (Cp, 4), and chelated ligand ,' (bpy, 1; phen, 2-4). H/D exchange was fastest in d-MeOD ( = 10 min, 37 °C, complex 1), no H/D exchange was observed in DMSO/DO, and d-MeOD enhanced the rate in CDCN. The proposed Rh(I)-fulvene intermediate was trapped by [4 + 2] Diels-Alder reactions with conjugated dienes and characterized.

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Background: In the past 60 years, L. has been an object of increasing interest because of the psychotropic effects of some of its constituents. These effects mainly arise from the cannabinoid Δ-tetrahydrocannabinol (Δ-THC).

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Lindblad Master Equations for Quantum Systems Coupled to Dissipative Bosonic Modes.

Phys Rev Lett

August 2022

School of Physics, International Joint Laboratory on Quantum Sensing and Quantum Metrology, Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.

We present a general approach to derive Lindblad master equations for a subsystem whose dynamics is coupled to dissipative bosonic modes. The derivation relies on a Schrieffer-Wolff transformation which allows us to eliminate the bosonic degrees of freedom after self-consistently determining their state as a function of the coupled quantum system. We apply this formalism to the dissipative Dicke model and derive a Lindblad master equation for the atomic spins, which includes the coherent and dissipative interactions mediated by the bosonic mode.

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We compared problem-solving in four sets of classical insight and analytic problems in the verbal and spatial domains, and examined the impact of externalization (verbalization or sketching). In a within-participants factorial design, we presented 24 classical insight and analytic problems, half verbal and half spatial. Participants solved these problems either while thinking aloud, while sketching, or in a baseline condition where neither was allowed.

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Accurate measurements of self-diffusion coefficients with benchtop NMR using a QM model-based approach.

Magn Reson Chem

December 2022

Laboratory of Reaction and Fluid Process Engineering, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 44, Kaiserslautern, 67663, Germany.

The measurement of self-diffusion coefficients using pulsed-field gradient (PFG) nuclear magnetic resonance (NMR) spectroscopy is a well-established method. Recently, benchtop NMR spectrometers with gradient coils have also been used, which greatly simplify these measurements. However, a disadvantage of benchtop NMR spectrometers is the lower resolution of the acquired NMR signals compared to high-field NMR spectrometers, which requires sophisticated analysis methods.

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Predicting the Tensile Behaviour of Ultra-High Performance Fibre-Reinforced Concrete from Single-Fibre Pull-Out Tests.

Materials (Basel)

July 2022

Institute of Concrete Structures and Structural Design, Faculty of Civil Engineering, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.

In this paper, a prediction model for the tensile behaviour of ultra-high performance fibre-reinforced concrete is proposed. It is based on integrating force contributions of all fibres crossing the crack plane. Piecewise linear models for the force contributions depending on fibre orientation and embedded length are fitted to force-slip curves obtained in single-fibre pull-out tests.

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The interfacial Dzyaloshinskii-Moriya Interaction (iDMI) is an antisymmetric exchange interaction that is induced by the broken inversion symmetry at the interface of, e.g., a ferromagnet/heavy metal.

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Interview with Prof. Dr. Benjamin List: Nobel Laureate in Chemistry 2021.

Chemistry

August 2022

Young Chemists' Network (JCF) of the German Chemical Society (GDCh), Varrentrappstr. 40-42, 60486, Frankfurt am Main, Germany.

In an interview with Benjamin List, winner of the 2021 Nobel Prize in Chemistry, members of the Young Chemists' Network (JCF) of the German Chemical Society (GDCh) asked him about his science, his career, and the academic system. Benjamin List, Director at the Max-Planck-Institut für Kohlenforschung in Germany, was awarded the Nobel Prize together with David W. C.

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Motivation: In this article, we consider how to evaluate survival distribution predictions with measures of discrimination. This is non-trivial as discrimination measures are the most commonly used in survival analysis and yet there is no clear method to derive a risk prediction from a distribution prediction. We survey methods proposed in literature and software and consider their respective advantages and disadvantages.

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Article Synopsis
  • - Epilepsy is a common neurological disorder, with focal epilepsy being the most prevalent, yet the genetic factors contributing to it are not fully understood.
  • - The study identifies that rare genetic mutations in the PIK3C2B gene disrupt lipid signaling, which in turn causes problems in synthesizing a specific lipid, leading to excessive activation of mTORC1 and heightened neuronal excitability.
  • - Targeting mTORC1 with inhibitors in mutant mice showed promise in preventing seizures, suggesting a new potential treatment strategy for certain patients with focal epilepsy.
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A building's indoor climate is an essential input variable for a variety of building physics computational models, simulations, and analyses. Precise knowledge of the indoor climate is necessary to minimize the risk of mold or moisture damage and is required to ensure minimum heat insulation standards in buildings. Detailed data are especially necessary for the progressive application of transient calculations, for example, concerning thermal comfort or energy consumption.

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We study experimentally the dissipative dynamics of ultracold bosonic gases in a dynamic disorder potential with tunable correlation time. First, we measure the heating rate of thermal clouds exposed to the dynamic potential and present a model of the heating process, revealing the microscopic origin of dissipation from a thermal, trapped cloud of bosons. Second, for Bose-Einstein condensates, we measure the particle loss rate induced by the dynamic environment.

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Environmental stress cracking (ESC) is one of the most prominent failure mechanisms for polymer components. The high sensitivity of plastics in regard to environmental influences has always meant that plastics as materials have been viewed very critically in outdoor applications. Recently, the massive occurrence of microplastics in the environment means that questions about the long-term stability of plastic parts and the studies of plastic fragmentation are of great scientific interest.

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Electrically conducting liquid droplets can be activated and moved by electrowetting-on-dielectric (EWOD) and optoelectrowetting (OEW). An important application is droplet manipulation in digital microfluidics (DMF, lab-on-a-chip 2.0) as a chip-sized chemical laboratory.

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Task-Specific Janus Materials in Heterogeneous Catalysis.

Angew Chem Int Ed Engl

September 2022

Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse 54, 67663, Kaiserslautern, Germany.

Janus materials are anisotropic nano- and microarchitectures with two different faces consisting of distinguishable or opposite physicochemical properties. In parallel with the discovery of new methods for the fabrication of these materials, decisive progress has been made in their application, for example, in biological science, catalysis, pharmaceuticals, and, more recently, in battery technology. This Minireview systematically covers recent and significant achievements in the application of task-specific Janus nanomaterials as heterogeneous catalysts in various types of chemical reactions, including reduction, oxidative desulfurization and dye degradation, asymmetric catalysis, biomass transformation, cascade reactions, oxidation, transition-metal-catalyzed cross-coupling reactions, electro- and photocatalytic reactions, as well as gas-phase reactions.

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Plant cells produce reactive oxygen species (ROS) as by-products of oxygen metabolism and for signal transduction. Depending on their concentration and their site of production, ROS can cause oxidative damage within the cell and must be effectively scavenged. Detoxification of the most stable ROS, hydrogen peroxide (HO), via the glutathione-ascorbate pathway may transiently alter the glutathione redox potential (E).

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Influence of Electronic Non-Equilibrium on Energy Distribution and Dissipation in Aluminum Studied with an Extended Two-Temperature Model.

Nanomaterials (Basel)

May 2022

Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, Erwin-Schrödinger-Straße 46, 67663 Kaiserslautern, Germany.

When an ultrashort laser pulse excites a metal surface, only a few of all the free electrons absorb a photon. The resulting non-equilibrium electron energy distribution thermalizes quickly to a hot Fermi distribution. The further energy dissipation is usually described in the framework of a two-temperature model, considering the phonons of the crystal lattice as a second subsystem.

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AMPA-type glutamate receptors (AMPARs) mediate fast excitatory neurotransmission, and the plastic modulation of their surface levels determines synaptic strength. AMPARs of different subunit compositions fulfill distinct roles in synaptic long-term potentiation (LTP) and depression (LTD) to enable learning. Largely unknown endocytic mechanisms mediate the subunit-selective regulation of the surface levels of GluA1-homomeric Ca-permeable (CP) versus heteromeric Ca-impermeable (CI) AMPARs.

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The handling of oxygen sensitive samples and growth of obligate anaerobic organisms requires the stringent exclusion of oxygen, which is omnipresent in our normal atmospheric environment. Anaerobic workstations (aka. Glove boxes) enable the handling of oxygen sensitive samples during complex procedures, or the long-term incubation of anaerobic organisms.

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Recent developments in nanomagnetism and spintronics have enabled the use of ultrafast spin physics for terahertz (THz) emission. Spintronic THz emitters, consisting of ferromagnetic (FM)/non-magnetic (NM) thin film heterostructures, have demonstrated impressive properties for the use in THz spectroscopy and have great potential in scientific and industrial applications. In this work, we focus on the impact of the FM/NM interface on the THz emission by investigating Fe/Pt bilayers with engineered interfaces.

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Nexus 20/21, Relationships Between Architecture and Mathematics.

Nexus Netw J

May 2022

UNSW Built Environment, UNSW, Sydney, 2052 Australia.

This letter from the editors commences by reporting on Nexus 20/21, the 13th international, interdisciplinary conference for architecture and mathematics. This event took place in July 2021 as an online conference. From over 50 presentations at the conference, the Scientific Committee nominated a series of works for potential inclusion in two special issues of the This letter introduces eleven papers selected for Vol.

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