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Temperature flow in pseudo Majorana functional renormalization for quantum spins
Get PDFWe implement the temperature flow scheme first proposed by Honerkamp and Salmhofer [Phys. Rev. B 64, 184516 2001 ] into the pseudo Majorana functional renormalization group method for quantum spin systems. Since the renormalization group parameter in this approach is a physical quantity, the temperature amp; 119879;, the numerical efficiency increases significantly compared to more conventional renormalization group parameters, especially when computing finite temperature phase diagrams. We first apply this method to determine the finite temperature phase diagram of the amp; 119869;1 amp; 8722; amp; 119869;2 Heisenberg model on the simple cubic lattice, where our findings support claims of a vanishingly small nonmagnetic phase around the high frustration point amp; 119869;2 0.25 amp; 8290; amp; 119869;1. Perhaps most importantly, we find the temperature flow scheme to be advantageous in detecting finite temperature phase transitions as, by construction, a phase transition is never encountered at an artificial, unphysical cutoff parameter. Finally, we apply the temperature flow scheme to the dipolar XXZ model on the square lattice, where we find a rich phase diagram with a large nonmagnetic regime down to the lowest accessible temperatures. Wherever a comparison with error controlled quantum Monte Carlo methods is applicable, we find excellent quantitative agreement with less than 5 deviation from the numerically exact result
Ga Ni Supported Catalytically Active Liquid Metal Solutions SCALMS for Selective Alkene Oligomerisation
No full textPatterns in Digital Twin Development
Get PDFDigital twins are powerful tools that replicate real world systems in a virtual environment, providing significant insights into the system s behavior and performance. This paper introduces a set of design patterns aimed at managing and developing digital twin systems with a focus on complex domains like synchrotron light sources. The patterns address key challenges such as interfacing with numerous process variables, maintaining synchronization between the digital twin and its physical counterpart, and switching between various operational modes of the twin. The three core patterns introduced are Simulation system facade, which abstracts the complexity of interacting with numerous subsystems by providing a stable and unified interface for all process variables; Simulation system update, which ensures efficient updates and consistent synchronization of process variables between the digital twin and the physical system; Twin state synchronization, which offers an intuitive interface to transition between different twin modes model, shadow, and twin , allowing the twin to dynamically adapt to various use cases. Together, these patterns provide a foundation for robust digital twin systems, setting the stage for future work in areas like communication with simulation engines and real world optimization. The proposed patterns enable developers to effectively manage the complexities of digital twin systems and enhance their applicability across diverse domain
Correction Face centered cubic carbon as a fourth basic carbon allotrope with properties of intrinsic semiconductors and ultra wide bandgap
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Resistive switching in mixed orthorhombic hexagonal RMnO3 R Y, Er polycrystalline thin films
No full textTargeting the Main Protease Mpro, nsp5 by Growth of Fragment Scaffolds Exploiting Structure Based Methodologies
Get PDFThe main protease Mpro, nsp5, of SARS CoV 2 SCoV2 is one of its most attractive drug targets. Here, we report primary screening data using nuclear magnetic resonance spectroscopy NMR of four different libraries and detailed follow up synthesis on the promising uracil containing fragment Z604 derived from these libraries. Z604 shows time dependent binding. Its inhibitory effect is sensitive to reducing conditions. Starting with Z604, we synthesized and characterized 13 compounds designed by fragment growth strategies. Each compound was characterized by NMR and or activity assays to investigate their interaction with Mpro. These investigations resulted in the four armed compound 35b that binds directly to Mpro. 35b could be cocrystallized with Mpro revealing its noncovalent binding mode, which fills all four active site subpockets. Herein, we describe the NMR derived fragment to hit pipeline and its application for the development of promising starting points for inhibitors of the main protease of SCoV
Structure of the Borrelia burgdorferi ATP dependent metalloprotease FtsH in its functionally relevant hexameric form
No full textATP dependent proteases FtsH are conserved in bacteria, mitochondria, and chloroplasts, where they play an essential role in degradation of misfolded unneeded membrane and cytosolic proteins. It has also been demonstrated that the FtsH homologous protein BB0789 is crucial for mouse and tick infectivity and in vitro growth of the Lyme disease causing agent Borrelia burgdorferi. This is not surprising, considering B. burgdorferi complex life cycle, residing in both in mammals and ticks, which requires a wide range of membrane proteins and short lived cytosolic regulatory proteins to invade and persist in the host organism. In the current study, we have solved the crystal structure of the cytosolic BB0789166 614, lacking both N terminal transmembrane amp; 945; helices and the small periplasmic domain. The structure revealed the arrangement of the AAA ATPase and the zinc dependent metalloprotease domains in a hexamer ring, which is essential for ATPase and proteolytic activity. The AAA domain was found in an ADP bound state, while the protease domain showed coordination of a zinc ion by two histidine residues and one aspartic acid residue. The loop region that forms the central pore in the oligomer was poorly defined in the crystal structure and therefore predicted by AlphaFold to complement the missing structural details, providing a complete picture of the functionally relevant hexameric form of BB0789. We confirmed that BB0789 is functionally active, possessing both protease and ATPase activities, thus providing novel structural functional insights into the protein, which is known to be absolutely necessary for B. burgdorferi to survive and cause Lyme diseas
Unveiling the Inner Structure of Micrometric Hollow Polymeric Fibers Using Synchrotron X Ray Nanotomography
No full textIn this study, a novel application of synchrotron X ray nanotomography based on high resolution full field transmission X ray microscopy for characterizing the structure and morphology of micrometric hollow polymeric fibers is presented. By employing postimage analysis using an open source software such as Tomviz and ImageJ, various key parameters in fiber morphology, including diameter, wall thickness, wall thickness distribution, pore size, porosity, and surface roughness, were assessed. Electrospun polycaprolactone fibers with micrometric diameters and submicrometric features with induced porosity via gas dissolution foaming were used to this aim. The acquired synchrotron X ray nanotomography data were analyzed using two approaches 3D tomographic reconstruction and 2D radiographic projection based analysis. The results of the combination of both approaches demonstrate unique capabilities of this technique, not achievable by other available techniques, allowing for a full characterization of the internal and external morphology and structure of the fibers as well as to obtain valuable qualitative insights into the overall fiber structur
Importance of Metal Support Interactions for CO2 Hydrogenation An Operando Near Ambient Pressure X ray Photoelectron Spectroscopy Study on Gold Loaded In2O3 and CeO2 Catalysts
Get PDFMetal support interactions, which are essential for the design of supported metal catalysts, used, e.g., for CO2 activation, are still only partially understood. In this study of gold loaded In2O3 and CeO2 catalysts during CO2 hydrogenation using near ambient pressure X ray photoelectron spectroscopy, supported by near edge X ray absorption fine structure, we demonstrate that the role of the noble metal strongly depends upon the choice of the support material. Temperature dependent analyses of X ray photoelectron spectra under reaction conditions reveal that gold is reduced on CeO2, enabling direct H2 activation, but oxidized on In2O3, leading to decreased activity of Au In2O3 compared to bare In2O3. At elevated temperatures, the catalytic activity of the In2O3 catalysts strongly increases as a result of facilitated CO2 and In2O3 based H2 activation, while the catalytic activity of Au CeO2 is limited by reoxidation by CO2. Our results underline the importance of operando studies for understanding metal support interactions to enable a rational support selection in the futur
Automated Flow Peptide Synthesis Enables Engineering of Proteins with Stabilized Transient Binding Pockets
No full textEngineering at the amino acid level is key to enhancing the properties of existing proteins in a desired manner. So far, protein engineering has been dominated by genetic approaches, which have been extremely powerful but only allow for minimal variations beyond the canonical amino acids. Chemical peptide synthesis allows the unrestricted incorporation of a vast set of unnatural amino acids with much broader functionalities, including the incorporation of post translational modifications or labels. Here we demonstrate the potential of chemical synthesis to generate proteins in a specific conformation, which would have been unattainable by recombinant protein expression. We use recently established rapid automated flow peptide synthesis combined with solid phase late stage modifications to rapidly generate a set of FK506 binding protein 51 constructs bearing defined intramolecular lactam bridges. This trapped an otherwise rarely populated transient pocket as confirmed by crystal structures which led to an up to 39 fold improved binding affinity for conformation selective ligands and represents a unique system for the development of ligands for this rare conformation. Overall, our results show how rapid automated flow peptide synthesis can be applied to precision protein engineerin