6,187 results match your criteria: "Karlsruhe Institute of Technology KIT; 76344 Eggenstein-Leopoldshafen[Affiliation]"

Four novel Co(II) coordination compounds 1-4 of the general formula [Co(L)][Co(NCY)]·CHCN (where L are tridentate ligands L1 = 2,6-bis(1-hexyl-1-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; = 0 for 1 and 3, = 0.5 for 2 and = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(L)] and tetracoordinate complex anion [Co(NCY)], with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively.

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The adhesion of cells to the extracellular matrix engages cell surface receptors such as integrins, proteoglycans and other types of cell adhesion molecules such as CD44. To closely examine the determinants of cell adhesion, herein we describe the generation of high-density peptide arrays and test the growth of cells on these multifunctionalized surfaces. The peptide library used consists of over 11,000 different sequences, either random or derived from existing proteins.

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Understanding the intricate relationship between molecular architecture and function underpins most challenges at the forefront of chemical innovation. Bond-forming reactions are particularly influenced by the topology of a chemical structure, both on small molecule scale and in larger macromolecular frameworks. Herein, we elucidate the impact that molecular architecture has on the photo-induced cyclisations of a series of monodisperse macromolecules with defined spacers between photodimerisable moieties, and examine the relationship between propensity for intramolecular cyclisation and intermolecular network formation.

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Sustained North Atlantic warming drove anomalously intense MIS 11c interglacial.

Nat Commun

July 2024

High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei, 10617, ROC, Taiwan.

The Marine Isotope Stage (MIS) 11c interglacial and its preceding glacial termination represent an enigmatically intense climate response to relatively weak insolation forcing. So far, a lack of radiometric age control has confounded a detailed assessment of the insolation-climate relationship during this period. Here, we present Th-dated speleothem proxy data from northern Italy and compare them with palaeoclimate records from the North Atlantic region.

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The dichotomous classification of self-talk statements into goal-directed as a more controlled type of self-talk and spontaneous as a more uncontrolled type of self-talk might be an oversimplification. To address this issue, two studies were conducted aiming to explore the idea that the distinction between the two self-talk types should rather be proportional and not mutually exclusive. In Study 1, football players took part in a penalty competition and were subsequently asked to state the self-talk they had before and after the penalty.

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3D-localization of gamma sources has the potential to improve the outcome of radio-guided surgery. The goal of this paper is to analyze the localization accuracy for point-like sources with a single coded aperture camera.We both simulated and measured a point-like241Am source at 17 positions distributed within the field of view of an experimental gamma camera.

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Structural Engineering of Prussian Blue Analogues Enabling All-Climate and Ultralong Cycling Sodium-Ion Batteries.

ACS Nano

July 2024

Institute of Carbon Neutralization, College of Chemistry and Materials Engineering, Wenzhou University, Zhejiang, Wenzhou 325035, China.

The development of cost-efficient, long-lifespan, and all-climate sodium-ion batteries is of great importance for advancing large-scale energy storage but is plagued by the lack of suitable cathode materials. Here, we report low-cost Na-rich Mn-based Prussian blue analogues with superior rate capability and ultralong cycling stability over 10,000 cycles via structural optimization with electrochemically inert Ni atoms. Their thermal stability, all-climate properties, and potential in full cells are investigated in detail.

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Polypy: A Framework to Interpret Polymer Properties from Mass Spectroscopy Data.

Polymers (Basel)

June 2024

Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.

Mass spectroscopy (MS) is a robust technique for polymer characterization, and it can provide the chemical fingerprint of a complete sample regarding polymer distribution chains. Nevertheless, polymer chemical properties such as polydispersity (Pd), average molecular mass (Mn), weight average molecular mass (Mw) and others are not determined by MS, as they are commonly characterized by gel permeation chromatography (GPC). In order to calculate polymer properties from MS, a Python script was developed to interpret polymer properties from spectroscopic raw data.

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Quantitative Characterization of RCA-Based DNA Hydrogels - Towards Rational Materials Design.

Chemistry

September 2024

Institute for Biological Interfaces (IBG-1), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, Eggenstein-Leopoldshafen, 76344, Germany.

DNA hydrogels hold significant promise for biomedical applications and can be synthesized through enzymatic Rolling Circle Amplification (RCA). Due to the exploratory nature of this emerging field, standardized RCA protocols specifying the impact of reaction parameters are currently lacking. This study varied template sequences and reagent concentrations, evaluating RCA synthesis efficiency and hydrogel mechanical properties through quantitative PCR (qPCR) and indentation measurements, respectively.

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Sub-Micron Replication of Fused Silica Glass and Amorphous Metals for Tool-Based Manufacturing.

Adv Sci (Weinh)

September 2024

Laboratory of Process Technology, NeptunLab, Department of Microsystems Engineering (IMTEK), University of Freiburg, 79108, Freiburg im Breisgau, Germany.

The growing importance of submicrometer-structured surfaces across a variety of different fields has driven progress in light manipulation, color diversity, water-repellency, and functional enhancements. To enable mass production, processes like hot-embossing (HE), roll-to-roll replication (R2R), and injection molding (IM) are essential due to their precision and material flexibility. However, these processes are tool-based manufacturing (TBM) techniques requiring metal molds, which are time-consuming and expensive to manufacture, as they mostly rely on galvanoforming using templates made via precision microlithography or two-photon-polymerization (2PP).

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Animals protect themself from microbial attacks by robust skins or a cuticle as in Caenorhabditis elegans. Nematode-trapping fungi, like Arthrobotrys flagrans, overcome the cuticle barrier and colonize the nematode body. While lytic enzymes are important for infection, small-secreted proteins (SSPs) without enzymatic activity, emerge as crucial virulence factors.

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High-entropy nanomaterials exhibit exceptional mechanical, physical, and chemical properties, finding applications in many industries. Peroxidases are metalloenzymes that accelerate the decomposition of hydrogen peroxide. This study uses the high-entropy approach to generate multimetal oxide-based nanozymes with peroxidase-like activity and explores their application as sensors in bioassays.

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Materials exhibiting thermally activated delayed fluorescence (TADF) based on transition metal complexes are currently gathering significant attention due to their technological potential. Their application extends beyond optoelectronics, in particular organic light-emitting diodes (OLEDs) and light-emitting electrochemical cells (LECs), and include also photocatalysis, sensing, and X-ray scintillators. From the perspective of sustainability, earth-abundant metal centers are preferred to rarer second- and third-transition series elements, thus determining a reduction in costs and toxicity but without compromising the overall performances.

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This insight article comments on: Ziegler C, Cochard, H, Stahl C, Bastien Gérard LF, Goret J, Heuret P, Levionnois S, Maillard P, Bonal D, Coste S. 2024. Residual water losses mediate the trade-off between growth and drought survival across saplings of 12 tropical rainforest tree species with contrasting hydraulic strategies.

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Heterocyclic Hemipiperazines: Multistimuli-Responsive Switches and Sensors for Zinc or Cadmium Ions.

Chemistry

September 2024

Institute of Biological and Chemical Systems - Functional Molecular Systems IBCS-FMS KIT, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131, Karlsruhe, Germany.

Advance in the design of molecular photoswitches - adapters that convert light into changes at molecular level - opens up exciting possibilities in preparing smart polymers, drugs photoactivated inside humans, or light-fueled nanomachines that might in the future operate in our bloodstream. Hemipiperazines are recently reported biocompatible molecular photoswitches based on cyclic dipeptides. Here we report a multistimuli-responsive hemipiperazine-based switch that reacts on light, solvents, acidity, or metal ions.

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A detailed analysis of the wave functions for the M to 5f excitations in the linear actinyls, UO, NpO, and PuO, and the theoretical X-ray absorption spectra obtained with these wave functions in comparison with experimental M-edge high-resolution X-ray absorption near-edge structure (HR-XANES) spectra is presented. The wave functions include full treatment of scalar and spin-orbit relativistic effects through the use of a Dirac-Coulomb Hamiltonian; many-body effects are included in determining the wave functions. The character of the excited states and of the active spaces to describe the wave functions for these states are investigated and analyzed.

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A trajectory surface hopping approach, which uses machine learning to speed up the most time-consuming steps, has been adopted to investigate the exciton transfer in light-harvesting systems. The present neural networks achieve high accuracy in predicting both Coulomb couplings and excitation energies. The latter are predicted taking into account the environment of the pigments.

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Online tuning of particle accelerators is a complex optimisation problem that continues to require manual intervention by experienced human operators. Autonomous tuning is a rapidly expanding field of research, where learning-based methods like Bayesian optimisation (BO) hold great promise in improving plant performance and reducing tuning times. At the same time, reinforcement learning (RL) is a capable method of learning intelligent controllers, and recent work shows that RL can also be used to train domain-specialised optimisers in so-called reinforcement learning-trained optimisation (RLO).

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Following the Structural Changes of Iron Oxides during Reduction under Transient Conditions.

ChemSusChem

December 2024

Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology, Engesserstr. 20, 76131, Karlsruhe, Germany.

Iron is considered as attractive energy carrier in a carbon-free, circular energy economy. The reduction of iron oxide is crucial for its application as a metal fuel as it determines the efficiency of the cycle. Temperature programmed reduction of α-FeO was monitored by complementary X-ray absorption spectroscopy (XAS) and diffraction (XRD) to obtain the phase composition with high time resolution.

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Record Quantum Tunneling Time in an Air-Stable Exchange-Bias Dysprosium Macrocycle.

J Am Chem Soc

July 2024

State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.

In recent years, dysprosium macrocycle single-molecule magnets (SMMs) have received increasing attention due to their excellent air/thermal stability, strong magnetic anisotropy, and rigid molecular skeleton. However, they usually display fast zero-field quantum tunneling of the magnetization (QTM) rate, severely hindering their data storage applications. Herein, we report the design, synthesis, and characterization of an air-stable monodecker didysprosium macrocycle integrating strong single-ion anisotropy, near-perfect local crystal field (CF) symmetry, and efficient exchange bias.

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The circadian clock represents a key timing system entrained by various periodic signals that ensure synchronization with the environment. Many investigations have pointed to the existence of two distinct circadian oscillators: one regulated by the light-dark cycle and the other set by feeding time. Blind cavefish have evolved under extreme conditions where they completely lack light exposure and experience food deprivation.

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Regulation of gene-edited plants in Europe: from the valley of tears into the shining sun?

aBIOTECH

June 2024

Department of Molecular Biology, Joseph Gottlieb Kölreuter Institute for Plant Sciences, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 4, 76131 Karlsruhe, Germany.

Some 20 years ago, the EU introduced complex regulatory rules for the growth of transgenic crops, which resulted in a de facto ban to grow these plants in fields within most European countries. With the rise of novel genome editing technologies, it has become possible to improve crops genetically in a directed way without the need for incorporation of foreign genes. Unfortunately, in 2018, the European Court of Justice ruled that such gene-edited plants are to be regulated like transgenic plants.

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Flavin-induced charge separation in transmembrane model peptides.

Org Biomol Chem

July 2024

Karlsruhe Institute of Technology (KIT), Institute of Organic Chemistry, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.

Hydrophobic peptide models derived from the α-helical transmembrane segment of the epidermal growth factor receptor were synthetically modified with a flavin amino acid as a photo-inducible charge donor and decorated with tryptophans along the helix as charge acceptors. The helical conformation of the peptides was conserved despite the modifications, notably also in lipid vesicles and multibilayers. Their ability to facilitate photo-induced transmembrane charge transport was examined by means of steady-state and time-resolved optical spectroscopy.

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Article Synopsis
  • Researchers created conjugates of a specific compound (benzothiophene-fused azacyclononyne BT9N-NH2) with fluorescent dyes to visualize azidoglycans inside cells.
  • The importance of the cycloalkyne core was shown by comparing the new reagents to existing DBCO- and BCN-dye conjugates.
  • To enhance specificity during bioconjugation within cells, the study suggests using the less reactive BT9N-dye reagents instead of the more reactive DBCO- and BCN-dye conjugates.
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