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  1. Article ; Online: Intrinsic optical signal imaging and targeted injections through a chronic cranial window of a head-fixed mouse

    Sigita Augustinaite / Bernd Kuhn

    STAR Protocols, Vol 2, Iss 3, Pp 100779- (2021)

    2021  

    Abstract: Summary: Intrinsic optical signal imaging (ISI) is a hemodynamic response-based technique to map the functional architecture of the cortex. ISI is often used as an auxiliary method to localize cortical areas for targeted electrophysiology, pharmacology, ... ...

    Abstract Summary: Intrinsic optical signal imaging (ISI) is a hemodynamic response-based technique to map the functional architecture of the cortex. ISI is often used as an auxiliary method to localize cortical areas for targeted electrophysiology, pharmacology, or imaging experiments. Here, we provide a protocol for ISI through a cranial window with an access port to identify the area of the primary visual cortex (V1) in a head-fixed mouse, followed by targeted viral vector injection, which enables subsequent two-photon imaging of V1 layer 6 corticothalamic neurons.For complete details on the use and execution of this protocol, please refer to our paper Augustinaite and Kuhn (2020b).
    Keywords Microscopy ; Model Organisms ; Neuroscience ; Science (General) ; Q1-390
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Dendritic coincidence detection in Purkinje neurons of awake mice

    Christopher J Roome / Bernd Kuhn

    eLife, Vol

    2020  Volume 9

    Abstract: Dendritic coincidence detection is fundamental to neuronal processing yet remains largely unexplored in awake animals. Specifically, the underlying dendritic voltage–calcium relationship has not been directly addressed. Here, using simultaneous voltage ... ...

    Abstract Dendritic coincidence detection is fundamental to neuronal processing yet remains largely unexplored in awake animals. Specifically, the underlying dendritic voltage–calcium relationship has not been directly addressed. Here, using simultaneous voltage and calcium two-photon imaging of Purkinje neuron spiny dendrites, we show how coincident synaptic inputs and resulting dendritic spikes modulate dendritic calcium signaling during sensory stimulation in awake mice. Sensory stimulation increased the rate of postsynaptic potentials and dendritic calcium spikes evoked by climbing fiber and parallel fiber synaptic input. These inputs are integrated in a time-dependent and nonlinear fashion to enhance the sensory-evoked dendritic calcium signal. Intrinsic supralinear dendritic mechanisms, including voltage-gated calcium channels and metabotropic glutamate receptors, are recruited cooperatively to expand the dynamic range of sensory-evoked dendritic calcium signals. This establishes how dendrites can use multiple interplaying mechanisms to perform coincidence detection, as a fundamental and ongoing feature of dendritic integration in behaving animals.
    Keywords Purkinje neuron ; voltage imaging ; dendrites ; two-photon microscopy ; cerebellum ; awake ; Medicine ; R ; Science ; Q ; Biology (General) ; QH301-705.5
    Language English
    Publishing date 2020-12-01T00:00:00Z
    Publisher eLife Sciences Publications Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Chronic Cranial Window for Imaging Cortical Activity in Head-Fixed Mice

    Sigita Augustinaite / Bernd Kuhn

    STAR Protocols, Vol 1, Iss 3, Pp 100194- (2020)

    2020  

    Abstract: Summary: Chronic cranial window surgery is a critical procedure for in vivo imaging in neuroscience. Here, we describe our surgical protocol with several subtle improvements that increase the success rate significantly. The window allows high-quality ... ...

    Abstract Summary: Chronic cranial window surgery is a critical procedure for in vivo imaging in neuroscience. Here, we describe our surgical protocol with several subtle improvements that increase the success rate significantly. The window allows high-quality imaging in head-fixed behaving mice within the first week after the surgical procedure and remains clear for months. We used this procedure to prepare mice for intrinsic signal imaging and two-photon imaging of layer 6 neurons in visual cortex.For complete details on the use and execution of this protocol, please refer to Augustinaite and Kuhn (2020).
    Keywords Microscopy ; Model Organisms ; Neuroscience ; Science (General) ; Q1-390
    Language English
    Publishing date 2020-12-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Details Matter in Structure-based Drug Design

    Bernd Kuhn / Jens-Uwe Peters / Markus G. Rudolph / Peter Mohr / Martin Stahl / Andreas Tosstorff

    CHIMIA, Vol 77, Iss 7/

    2023  Volume 8

    Abstract: Successful structure-based drug design (SBDD) requires the optimization of interactions with the target protein and the minimization of ligand strain. Both factors are often modulated by small changes in the chemical structure which can lead to profound ... ...

    Abstract Successful structure-based drug design (SBDD) requires the optimization of interactions with the target protein and the minimization of ligand strain. Both factors are often modulated by small changes in the chemical structure which can lead to profound changes in the preferred conformation and interaction preferences of the ligand. We draw from examples of a Roche project targeting phosphodiesterase 10 to highlight that details matter in SBDD. Data mining in crystal structure databases can help to identify these sometimes subtle effects, but it is also a great resource to learn about molecular recognition in general and can be used as part of molecular design tools. We illustrate the use of the Cambridge Structural Database for identifying preferred structural motifs for intramolecular hydrogen bonding and of the Protein Data Bank for deriving propensities for protein-ligand interactions.
    Keywords Intramolecular hydrogen bond ; Ligand strain ; Molecular interactions ; PDE10 ; Chemistry ; QD1-999
    Subject code 500
    Language German
    Publishing date 2023-08-01T00:00:00Z
    Publisher Swiss Chemical Society
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Simultaneous dendritic voltage and calcium imaging and somatic recording from Purkinje neurons in awake mice

    Christopher J. Roome / Bernd Kuhn

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 14

    Abstract: Dendritic integration is important for information processing in the brain. Here, in awake mice, authors combine simultaneous dendritic recording of voltage and calcium signals, with somatic recording from Purkinje neurons, enabling characterization of ... ...

    Abstract Dendritic integration is important for information processing in the brain. Here, in awake mice, authors combine simultaneous dendritic recording of voltage and calcium signals, with somatic recording from Purkinje neurons, enabling characterization of dendritic spiking, action potential backpropagation, and ‘hotspots’ in spiny dendrites.
    Keywords Science ; Q
    Language English
    Publishing date 2018-08-01T00:00:00Z
    Publisher Nature Publishing Group
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Simultaneous dendritic voltage and calcium imaging and somatic recording from Purkinje neurons in awake mice

    Christopher J. Roome / Bernd Kuhn

    Nature Communications, Vol 9, Iss 1, Pp 1-

    2018  Volume 14

    Abstract: Dendritic integration is important for information processing in the brain. Here, in awake mice, authors combine simultaneous dendritic recording of voltage and calcium signals, with somatic recording from Purkinje neurons, enabling characterization of ... ...

    Abstract Dendritic integration is important for information processing in the brain. Here, in awake mice, authors combine simultaneous dendritic recording of voltage and calcium signals, with somatic recording from Purkinje neurons, enabling characterization of dendritic spiking, action potential backpropagation, and ‘hotspots’ in spiny dendrites.
    Keywords Science ; Q
    Language English
    Publishing date 2018-08-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Impact of Thermomechanical Fatigue on Microstructure Evolution of a Ferritic-Martensitic 9 Cr and a Ferritic, Stainless 22 Cr Steel

    Bernd Kuhn / Jennifer Lopez Barrilao / Torsten Fischer

    Applied Sciences, Vol 10, Iss 6338, p

    2020  Volume 6338

    Abstract: The highly flexible operation schemes of future thermal energy conversion systems (concentrating solar power, heat storage and backup plants, power-2-X technologies) necessitate increased damage tolerance and durability of the applied structural ... ...

    Abstract The highly flexible operation schemes of future thermal energy conversion systems (concentrating solar power, heat storage and backup plants, power-2-X technologies) necessitate increased damage tolerance and durability of the applied structural materials under cyclic loading. Resistance to fatigue, especially thermomechanical fatigue and the associated implications for material selection, lifetime and its assessment, are issues not considered adequately by the power engineering materials community yet. This paper investigates the principal microstructural evolution, damage and failure of two steels in thermomechanical fatigue loading: Ferritic-martensitic grade 91 steel, a state of the art 9 wt % Cr power engineering grade and the 22 wt % Cr, ferritic, stainless Crofer ® 22 H (trade name of VDM Metals GmbH, Germany; under license of Forschungszentrum Juelich GmbH) steel. While the ferritic-martensitic grade 91 steel suffers pronounced microstructural instability, the ferritic Crofer ® 22 H provides superior microstructural stability and offers increased fatigue lifetime and more forgiving failure characteristics, because of innovative stabilization by (thermomechanically triggered) precipitation of fine Laves phase particles. The potential for further development of this mechanism of strengthening against fatigue is addressed.
    Keywords thermomechanical fatigue ; microstructural (in) stability ; Laves phase ; cyclic softening/strengthening ; thermomechanically triggered precipitation ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 669 ; 621
    Language English
    Publishing date 2020-09-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article ; Online: Generation of a human embryonic stem cell reporter line, TMEM119-EGFP, for the visualisation of in vitro differentiated human microglia

    Charlotte R. Denman / Hoang-Dai Tran / Min-Kyoung Shin / Jisoo Ryu / Bernd Kuhn / Junghyun Jo

    Stem Cell Research, Vol 73, Iss , Pp 103264- (2023)

    2023  

    Abstract: Transmembrane protein 119 (TMEM119) is a recently identified microglia marker that is not expressed by other immune cells. Using CRISPR/Cas9 technology, we introduced enhanced green fluorescence protein (EGFP), into the H9 WA-09 human embryonic stem cell ...

    Abstract Transmembrane protein 119 (TMEM119) is a recently identified microglia marker that is not expressed by other immune cells. Using CRISPR/Cas9 technology, we introduced enhanced green fluorescence protein (EGFP), into the H9 WA-09 human embryonic stem cell line, directly before the TMEM119 stop codon. Sanger sequencing confirmed successful insertion of the EGFP sequence. The newly created cell line expressed a normal morphology and karyotype, several pluripotency markers, and the ability to differentiate into all three germ layers. H9-TMEM119-EGFP can be used to provide a deeper understanding of the role of TMEM119 in microglia by monitoring its expression under different experimental conditions.
    Keywords Biology (General) ; QH301-705.5
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Impact of Tungsten on Thermomechanically Induced Precipitation of Laves Phase in High Performance Ferritic (HiperFer) Stainless Steels

    Jana Pöpperlová / Xiuru Fan / Bernd Kuhn / Wolfgang Bleck / Ulrich Krupp

    Applied Sciences, Vol 10, Iss 4472, p

    2020  Volume 4472

    Abstract: High-chromium ferritic stainless steels strengthened by Laves phase precipitates were developed for a high-temperature application in steam power plants. The impact of tungsten content on the precipitation of the intermetallic Laves phase during the ... ...

    Abstract High-chromium ferritic stainless steels strengthened by Laves phase precipitates were developed for a high-temperature application in steam power plants. The impact of tungsten content on the precipitation of the intermetallic Laves phase during the newly developed thermomechanical process route was investigated. Due to rapid thermomechanically induced precipitation, a considerable reduction in processing time in comparison to the conventional solely thermal two-step processing of high chromium ferritic steels was achieved. Nevertheless, comparable mechanical properties at room temperature, i.e., the ultimate tensile strength of 712 MPa and the yield strength of 434 MPa, were obtained. The microstructure was analyzed by scanning electron microscopy (SEM) in combination with digital particle analysis, to estimate the particle size and the phase fraction of the Laves phase. The mean particle size of 52 nm and the volume fraction of 4.11% were achieved. Due to the tungsten content, an increase in the volume fraction and particle size was observed, giving rise to the higher strengthening effect.
    Keywords high chromium ferritic steel ; intermetallic phase ; Laves phase ; precipitation ; thermomechanical treatment ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 669
    Language English
    Publishing date 2020-06-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Analysis of the Thermomechanical Fatigue Behavior of Fully Ferritic High Chromium Steel Crofer ® 22 H with Cyclic Indentation Testing

    Bastian Blinn / David Görzen / Torsten Fischer / Bernd Kuhn / Tilmann Beck

    Applied Sciences, Vol 10, Iss 6461, p

    2020  Volume 6461

    Abstract: The 22 wt.% Cr, fully ferritic stainless steel Crofer ® 22 H has higher thermomechanical fatigue (TMF)- lifetime compared to advanced ferritic-martensitic P91, which is assumed to be caused by different damage tolerance, leading to differences in crack ... ...

    Abstract The 22 wt.% Cr, fully ferritic stainless steel Crofer ® 22 H has higher thermomechanical fatigue (TMF)- lifetime compared to advanced ferritic-martensitic P91, which is assumed to be caused by different damage tolerance, leading to differences in crack propagation and failure mechanisms. To analyze this, instrumented cyclic indentation tests (CITs) were used because the material’s cyclic hardening potential—which strongly correlates with damage tolerance, can be determined by analyzing the deformation behavior in CITs. In the presented work, CITs were performed for both materials at specimens loaded for different numbers of TMF-cycles. These investigations show higher damage tolerance for Crofer ® 22 H and demonstrate changes in damage tolerance during TMF-loading for both materials, which correlates with the cyclic deformation behavior observed in TMF-tests. Furthermore, the results obtained at Crofer ® 22 H indicate an increase of damage tolerance in the second half of TMF-lifetime, which cannot be observed for P91. Moreover, CITs were performed at Crofer ® 22 H in the vicinity of a fatigue crack, enabling to locally analyze the damage tolerance. These CITs show differences between crack edges and the crack tip. Conclusively, the presented results demonstrate that CITs can be utilized to analyze TMF-induced changes in damage tolerance.
    Keywords cyclic hardening potential ; damage tolerance ; microstructural evolution ; cyclic indentation test ; thermomechanical fatigue ; PhyBaL CHT ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 669
    Language English
    Publishing date 2020-09-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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