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Adhikari S, Li J, Wang Y, Ruijs L, Liu J, Koopmans B, Orrit M, Lavrijsen R. Optical Monitoring of the Magnetization Switching of Single Synthetic-Antiferromagnetic Nanoplatelets with Perpendicular Magnetic Anisotropy. ACS Photonics 2023; 10:1512-1518. [PMID: 37215319 PMCID: PMC10197163 DOI: 10.1021/acsphotonics.3c00123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Indexed: 05/24/2023]
Abstract
Synthetic antiferromagnetic nanoplatelets (NPs) with a large perpendicular magnetic anisotropy (SAF-PMA NPs) have a large potential in future local mechanical torque-transfer applications for e.g., biomedicine. However, the mechanisms of magnetization switching of these structures at the nanoscale are not well understood. Here, we have used a simple and relatively fast single-particle optical technique that goes beyond the diffraction limit to measure photothermal magnetic circular dichroism (PT MCD). This allows us to study the magnetization switching as a function of applied magnetic field of single 122 nm diameter SAF-PMA NPs with a thickness of 15 nm. We extract and discuss the differences between the switching field distributions of large ensembles of NPs and of single NPs. In particular, single-particle PT MCD allows us to address the spatial and temporal heterogeneity of the magnetic switching fields of the NPs at the single-particle level. We expect this new insight to help understand better the dynamic torque transfer, e.g., in biomedical and microfluidic applications.
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Affiliation(s)
- S. Adhikari
- Huygens-Kamerlingh
Onnes Laboratory, LION, 2300 RA Leiden, Netherlands
| | - J. Li
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - Y. Wang
- Huygens-Kamerlingh
Onnes Laboratory, LION, 2300 RA Leiden, Netherlands
- School
of Mechatronics Engineering, Harbin Institute
of Technology, Harbin 150001, P. R. China
| | - L. Ruijs
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - J. Liu
- School
of Mechatronics Engineering, Harbin Institute
of Technology, Harbin 150001, P. R. China
| | - B. Koopmans
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
| | - M. Orrit
- Huygens-Kamerlingh
Onnes Laboratory, LION, 2300 RA Leiden, Netherlands
| | - R. Lavrijsen
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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2
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van Gerresheim EF, Müller-Schiffmann A, Schäble S, Koopmans B, Loos M, Korth C. Soluble amyloid-β dimers are resistant to amyloid-β prion conversion in vivo suggesting antiprion properties. Neuropathol Appl Neurobiol 2023; 49:e12895. [PMID: 36861420 DOI: 10.1111/nan.12895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/21/2023] [Indexed: 03/03/2023]
Abstract
According to the instructions for authors, short communications should be published without abstract.
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Affiliation(s)
- Else F van Gerresheim
- Department of Neuropathology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | | | - Sandra Schäble
- Comparative Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Bastijn Koopmans
- Sylics (Synaptologics BV), Antonie van Leeuwenhoeklaan 9, Bilthoven, The Netherlands
| | - Maarten Loos
- Sylics (Synaptologics BV), Antonie van Leeuwenhoeklaan 9, Bilthoven, The Netherlands
| | - Carsten Korth
- Department of Neuropathology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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3
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Michailidou I, Vreijling J, Rumpf M, Loos M, Koopmans B, Vlek N, Straat N, Agaser C, Kuipers TB, Mei H, Baas F, Fluiter K. The systemic inhibition of the terminal complement system reduces neuroinflammation but does not improve motor function in mouse models of CMT1A with overexpressed PMP22. Curr Res Neurobiol 2023; 4:100077. [PMID: 36926597 PMCID: PMC10011818 DOI: 10.1016/j.crneur.2023.100077] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 12/13/2022] [Accepted: 01/27/2023] [Indexed: 02/07/2023] Open
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is the most prevalent hereditary demyelinating neuropathy. This autosomal, dominantly inherited disease is caused by a duplication on chromosome 17p which includes the peripheral myelin protein 22 (PMP22) gene. There is clinical evidence that the disability in CMT1A is to a large extend due to axonal damage rather than demyelination. Over-expression of PMP22 is recently thought to impede cholesterol trafficking causing a total shutdown of local cholesterol and lipid synthesis in the Schwann cells, thus disturbing their ability to remyelinate. But there is a large variety in disease burden between CMT1A patients with the same genetic defect, indicating the presence of modifying factors that affect disease severity. One of these potential factors is the immune system. Several reports have described patients with co-occurrence of CMT1A with chronic inflammatory demyelinating disease or Guillain-Barré syndrome. We have previously shown in multiple animal models that the innate immune system and specifically the terminal complement system is a driver of inflammatory demyelination. To test the contribution of the terminal complement system to neuroinflammation and disease progression in CMT1A, we inhibited systemic complement C6 in two transgenic mouse models for CMT1A, the C3-PMP22 and C3-PMP22 c-JunP0Cre models. Both models over-express human PMP22, and one (C3-PMP22 c-JunP0Cre) also has a Schwann cell-specific knockout of c-Jun, a crucial regulator of myelination controlling autophagy. We found that systemic inhibition of C6 using antisense oligonucleotides affects the neuroinflammation, Rho GTPase and ERK/MAPK signalling pathways in the CMT1A mouse models. The cholesterol synthesis pathway remained unaffected. Analysis of motor function during treatment with C6 antisense oligonucleotides did not reveal any significant improvement in the CMT1A mouse models. This study shows that the contribution of the terminal complement system to progressive loss of motor function in the CMT1A mouse models tested is limited.
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Affiliation(s)
- Iliana Michailidou
- Dept of Clinical Genetics, LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Jeroen Vreijling
- Dept of Clinical Genetics, LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Matthijs Rumpf
- Dept of Clinical Genetics, LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Maarten Loos
- Sylics (Synaptologics B.V.), Bilthoven, the Netherlands
| | | | - Nina Vlek
- Sylics (Synaptologics B.V.), Bilthoven, the Netherlands
| | - Nina Straat
- Sylics (Synaptologics B.V.), Bilthoven, the Netherlands
| | - Cedrick Agaser
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Thomas B Kuipers
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Department of Biomedical Data Sciences LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Frank Baas
- Dept of Clinical Genetics, LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | - Kees Fluiter
- Dept of Clinical Genetics, LUMC, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
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4
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Beens M, de Mare KA, Duine RA, Koopmans B. Spin-polarized hot electron transport versus spin pumping mediated by local heating. J Phys Condens Matter 2022; 35:035803. [PMID: 36368045 DOI: 10.1088/1361-648x/aca24e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/11/2022] [Indexed: 06/16/2023]
Abstract
A 'toy model'-aimed at capturing the essential physics-is presented that jointly describes spin-polarized hot electron transport and spin pumping driven by local heating. These two processes both contribute to spin-current generation in laser-excited magnetic heterostructures. The model is used to compare the two contributions directly. The spin-polarized hot electron current is modeled as one generation of hot electrons with a spin-dependent excitation and relaxation scheme. Upon decay, the excess energy of the hot electrons is transferred to a thermalized electron bath. The elevated electron temperature leads to an increased rate of electron-magnon scattering processes and yields a local accumulation of spin. This process is dubbed as spin pumping by local heating. The built-up spin accumulation is effectively driven out of the ferromagnetic system by (interfacial) electron transport. Within our model, the injected spin current is dominated by the contribution resulting from spin pumping, while the hot electron spin current remains relatively small. We derive that this observation is related to the ratio between the Fermi temperature and Curie temperature, and we show what other fundamental parameters play a role.
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Affiliation(s)
- M Beens
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - K A de Mare
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - R A Duine
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
- Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands
| | - B Koopmans
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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Arroyo-Araujo M, Voelkl B, Laloux C, Novak J, Koopmans B, Waldron AM, Seiffert I, Stirling H, Aulehner K, Janhunen SK, Ramboz S, Potschka H, Holappa J, Fine T, Loos M, Boulanger B, Würbel H, Kas MJ. Systematic assessment of the replicability and generalizability of preclinical findings: Impact of protocol harmonization across laboratory sites. PLoS Biol 2022; 20:e3001886. [PMID: 36417471 PMCID: PMC9728859 DOI: 10.1371/journal.pbio.3001886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 12/07/2022] [Accepted: 10/24/2022] [Indexed: 11/25/2022] Open
Abstract
The influence of protocol standardization between laboratories on their replicability of preclinical results has not been addressed in a systematic way. While standardization is considered good research practice as a means to control for undesired external noise (i.e., highly variable results), some reports suggest that standardized protocols may lead to idiosyncratic results, thus undermining replicability. Through the EQIPD consortium, a multi-lab collaboration between academic and industry partners, we aimed to elucidate parameters that impact the replicability of preclinical animal studies. To this end, 3 experimental protocols were implemented across 7 laboratories. The replicability of results was determined using the distance travelled in an open field after administration of pharmacological compounds known to modulate locomotor activity (MK-801, diazepam, and clozapine) in C57BL/6 mice as a worked example. The goal was to determine whether harmonization of study protocols across laboratories improves the replicability of the results and whether replicability can be further improved by systematic variation (heterogenization) of 2 environmental factors (time of testing and light intensity during testing) within laboratories. Protocols were tested in 3 consecutive stages and differed in the extent of harmonization across laboratories and standardization within laboratories: stage 1, minimally aligned across sites (local protocol); stage 2, fully aligned across sites (harmonized protocol) with and without systematic variation (standardized and heterogenized cohort); and stage 3, fully aligned across sites (standardized protocol) with a different compound. All protocols resulted in consistent treatment effects across laboratories, which were also replicated within laboratories across the different stages. Harmonization of protocols across laboratories reduced between-lab variability substantially compared to each lab using their local protocol. In contrast, the environmental factors chosen to introduce systematic variation within laboratories did not affect the behavioral outcome. Therefore, heterogenization did not reduce between-lab variability further compared to the harmonization of the standardized protocol. Altogether, these findings demonstrate that subtle variations between lab-specific study protocols may introduce variation across independent replicate studies even after protocol harmonization and that systematic heterogenization of environmental factors may not be sufficient to account for such between-lab variation. Differences in replicability of results within and between laboratories highlight the ubiquity of study-specific variation due to between-lab variability, the importance of transparent and fine-grained reporting of methodologies and research protocols, and the importance of independent study replication.
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Affiliation(s)
- María Arroyo-Araujo
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Bernhard Voelkl
- Animal Welfare Division, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Janja Novak
- Animal Welfare Division, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | - Ann-Marie Waldron
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, Muenchen, Germany
| | - Isabel Seiffert
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, Muenchen, Germany
| | - Helen Stirling
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, Muenchen, Germany
| | - Katharina Aulehner
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, Muenchen, Germany
| | | | - Sylvie Ramboz
- PsychoGenics Inc., New Jersey, Paramus, United States of America
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, Muenchen, Germany
| | | | | | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, the Netherlands
| | | | - Hanno Würbel
- Animal Welfare Division, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Martien J. Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
- * E-mail:
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6
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Rivares C, Vignaud A, Noort W, Koopmans B, Loos M, Kalinichev M, Jaspers RT. Glycine receptor subunit-ß -deficiency in a mouse model of spasticity results in attenuated physical performance, growth and muscle strength. Am J Physiol Regul Integr Comp Physiol 2022; 322:R368-R388. [PMID: 35108108 PMCID: PMC9054346 DOI: 10.1152/ajpregu.00242.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Spasticity is the most common neurological disorder associated with increased muscle contraction causing impaired movement and gait. The aim of this study was to characterize the physical performance, skeletal muscle function, and phenotype of mice with a hereditary spastic mutation (B6.Cg-Glrbspa/J). Motor function, gait, and physical activity of juvenile and adult spastic mice and the morphological, histological, and mechanical characteristics of their soleus and gastrocnemius medialis muscles were compared with those of their wild-type (WT) littermates. Spastic mice showed attenuated growth, impaired motor function, and low physical activity. Gait of spastic mice was characterized by a typical hopping pattern. Spastic mice showed lower muscle forces, which were related to the smaller physiological cross-sectional area of spastic muscles. The muscle-tendon complex length-force relationship of adult gastrocnemius medialis was shifted toward shorter lengths, which was explained by attenuated longitudinal tibia growth. Spastic gastrocnemius medialis was more fatigue resistant than WT gastrocnemius medialis. This was largely explained by a higher mitochondrial content in muscle fibers and relatively higher percentage of slow-type muscle fibers. Muscles of juvenile spastic mice showed similar differences compared with WT juvenile mice, but these were less pronounced than between adult mice. This study shows that in spastic mice, disturbed motor function and gait is likely to be the result of hyperactivity of skeletal muscle and impaired skeletal muscle growth, which progress with age.
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Affiliation(s)
- Cintia Rivares
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
| | | | - Wendy Noort
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
| | | | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, the Netherlands
| | | | - Richard T Jaspers
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
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Chen S, Siedhoff HR, Zhang H, Liu P, Balderrama A, Li R, Johnson C, Greenlief CM, Koopmans B, Hoffman T, DePalma RG, Li DP, Cui J, Gu Z. Low-intensity blast induces acute glutamatergic hyperexcitability in mouse hippocampus leading to long-term learning deficits and altered expression of proteins involved in synaptic plasticity and serine protease inhibitors. Neurobiol Dis 2022; 165:105634. [PMID: 35077822 DOI: 10.1016/j.nbd.2022.105634] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 11/26/2022] Open
Abstract
Neurocognitive consequences of blast-induced traumatic brain injury (bTBI) pose significant concerns for military service members and veterans with the majority of "invisible injury." However, the underlying mechanism of such mild bTBI by low-intensity blast (LIB) exposure for long-term cognitive and mental deficits remains elusive. Our previous studies have shown that mice exposed to LIB result in nanoscale ultrastructural abnormalities in the absence of gross or apparent cellular damage in the brain. Here we tested the hypothesis that glutamatergic hyperexcitability may contribute to long-term learning deficits. Using brain slice electrophysiological recordings, we found an increase in averaged frequencies with a burst pattern of miniature excitatory postsynaptic currents (mEPSCs) in hippocampal CA3 neurons in LIB-exposed mice at 1- and 7-days post injury, which was blocked by a specific NMDA receptor antagonist AP5. In addition, cognitive function assessed at 3-months post LIB exposure by automated home-cage monitoring showed deficits in dynamic patterns of discrimination learning and cognitive flexibility in LIB-exposed mice. Collected hippocampal tissue was further processed for quantitative global-proteomic analysis. Advanced data-independent acquisition for quantitative tandem mass spectrometry analysis identified altered expression of proteins involved in synaptic plasticity and serine protease inhibitors in LIB-exposed mice. Some were correlated with the ability of discrimination learning and cognitive flexibility. These findings show that acute glutamatergic hyperexcitability in the hippocampus induced by LIB may contribute to long-term cognitive dysfunction and protein alterations. Studies using this military-relevant mouse model of mild bTBI provide valuable insights into developing a potential therapeutic strategy to ameliorate hyperexcitability-modulated LIB injuries.
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Affiliation(s)
- Shanyan Chen
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Heather R Siedhoff
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Hua Zhang
- Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Pei Liu
- Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, MO 65211, USA
| | - Ashley Balderrama
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Runting Li
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Catherine Johnson
- Department of Mining and Nuclear Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - C Michael Greenlief
- Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, MO 65211, USA
| | | | - Timothy Hoffman
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Ralph G DePalma
- Office of Research and Development, Department of Veterans Affairs, Washington DC 20420, USA; Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - De-Pei Li
- Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Jiankun Cui
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA.
| | - Zezong Gu
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA.
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Siedhoff HR, Chen S, Balderrama A, Sun GY, Koopmans B, DePalma RG, Cui J, Gu Z. Long-Term Effects of Low-Intensity Blast Non-Inertial Brain Injury on Anxiety-Like Behaviors in Mice: Home-Cage Monitoring Assessments. Neurotrauma Rep 2022; 3:27-38. [PMID: 35141713 PMCID: PMC8820222 DOI: 10.1089/neur.2021.0063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mild traumatic brain injury induced by low-intensity blast (LIB) exposure poses concerns in military personnel. Using an open-field, non-inertial blast model and assessments by conventional behavioral tests, our previous studies revealed early-phase anxiety-like behaviors in LIB-exposed mice. However, the impact of LIB upon long-term anxiety-like behaviors requires clarification. This study applied a highly sensitive automated home-cage monitoring (HCM) system, which minimized human intervention and environmental changes, to assess anxiety-like responses in mice 3 months after LIB exposure. Initial assessment of 72-h spontaneous activities in a natural cage condition over multiple light and dark phases showed altered sheltering behaviors. LIB-exposed mice exhibited a subtle, but significantly decreased, duration of short shelter visits as compared to sham controls. Other measured responses between LIB-exposed mice and sham controls were insignificant. When behavioral assessments were performed in a challenged condition using an aversive spotlight, LIB-exposed mice demonstrated a significantly higher frequency of movements of shorter distance and duration per movement. Taken together, these findings demonstrated the presence of chronic anxiety-like behaviors assessed by the HCM system under both natural and challenged conditions in mice occurring post-LIB exposure. This model thus provides a platform to test for screening and interventions on anxiety disorders occurring after LIB non-inertial brain injury.
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Affiliation(s)
- Heather R. Siedhoff
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, Missouri, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Shanyan Chen
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, Missouri, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Ashley Balderrama
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, Missouri, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Grace Y. Sun
- Department of Biochemistry, University of Missouri School of Medicine, Columbia, Missouri, USA
| | | | - Ralph G. DePalma
- Office of Research and Development, Department of Veterans Affairs, Washington, DC, USA; Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Jiankun Cui
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, Missouri, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Zezong Gu
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, Missouri, USA
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, Missouri, USA
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9
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Grieco F, Bernstein BJ, Biemans B, Bikovski L, Burnett CJ, Cushman JD, van Dam EA, Fry SA, Richmond-Hacham B, Homberg JR, Kas MJH, Kessels HW, Koopmans B, Krashes MJ, Krishnan V, Logan S, Loos M, McCann KE, Parduzi Q, Pick CG, Prevot TD, Riedel G, Robinson L, Sadighi M, Smit AB, Sonntag W, Roelofs RF, Tegelenbosch RAJ, Noldus LPJJ. Measuring Behavior in the Home Cage: Study Design, Applications, Challenges, and Perspectives. Front Behav Neurosci 2021; 15:735387. [PMID: 34630052 PMCID: PMC8498589 DOI: 10.3389/fnbeh.2021.735387] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022] Open
Abstract
The reproducibility crisis (or replication crisis) in biomedical research is a particularly existential and under-addressed issue in the field of behavioral neuroscience, where, in spite of efforts to standardize testing and assay protocols, several known and unknown sources of confounding environmental factors add to variance. Human interference is a major contributor to variability both within and across laboratories, as well as novelty-induced anxiety. Attempts to reduce human interference and to measure more "natural" behaviors in subjects has led to the development of automated home-cage monitoring systems. These systems enable prolonged and longitudinal recordings, and provide large continuous measures of spontaneous behavior that can be analyzed across multiple time scales. In this review, a diverse team of neuroscientists and product developers share their experiences using such an automated monitoring system that combines Noldus PhenoTyper® home-cages and the video-based tracking software, EthoVision® XT, to extract digital biomarkers of motor, emotional, social and cognitive behavior. After presenting our working definition of a "home-cage", we compare home-cage testing with more conventional out-of-cage tests (e.g., the open field) and outline the various advantages of the former, including opportunities for within-subject analyses and assessments of circadian and ultradian activity. Next, we address technical issues pertaining to the acquisition of behavioral data, such as the fine-tuning of the tracking software and the potential for integration with biotelemetry and optogenetics. Finally, we provide guidance on which behavioral measures to emphasize, how to filter, segment, and analyze behavior, and how to use analysis scripts. We summarize how the PhenoTyper has applications to study neuropharmacology as well as animal models of neurodegenerative and neuropsychiatric illness. Looking forward, we examine current challenges and the impact of new developments. Examples include the automated recognition of specific behaviors, unambiguous tracking of individuals in a social context, the development of more animal-centered measures of behavior and ways of dealing with large datasets. Together, we advocate that by embracing standardized home-cage monitoring platforms like the PhenoTyper, we are poised to directly assess issues pertaining to reproducibility, and more importantly, measure features of rodent behavior under more ethologically relevant scenarios.
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Affiliation(s)
| | - Briana J Bernstein
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Lior Bikovski
- Myers Neuro-Behavioral Core Facility, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- School of Behavioral Sciences, Netanya Academic College, Netanya, Israel
| | - C Joseph Burnett
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jesse D Cushman
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Sydney A Fry
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | - Bar Richmond-Hacham
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - Martien J H Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Helmut W Kessels
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | | | - Michael J Krashes
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Vaishnav Krishnan
- Laboratory of Epilepsy and Emotional Behavior, Baylor Comprehensive Epilepsy Center, Departments of Neurology, Neuroscience, and Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX, United States
| | - Sreemathi Logan
- Department of Rehabilitation Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, Netherlands
| | - Katharine E McCann
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- The Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel Aviv University, Tel Aviv, Israel
| | - Thomas D Prevot
- Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gernot Riedel
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Lianne Robinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Mina Sadighi
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - William Sonntag
- Department of Biochemistry & Molecular Biology, Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | | | | | - Lucas P J J Noldus
- Noldus Information Technology BV, Wageningen, Netherlands
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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10
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Engelbeen S, Aartsma-Rus A, Koopmans B, Loos M, van Putten M. Assessment of Behavioral Characteristics With Procedures of Minimal Human Interference in the mdx Mouse Model for Duchenne Muscular Dystrophy. Front Behav Neurosci 2021; 14:629043. [PMID: 33551769 PMCID: PMC7855581 DOI: 10.3389/fnbeh.2020.629043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 12/15/2020] [Indexed: 11/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe, progressive neuromuscular disorder caused by mutations in the DMD gene resulting in loss of functional dystrophin protein. The muscle dystrophin isoform is essential to protect muscles from contraction-induced damage. However, most dystrophin isoforms are expressed in the brain. In addition to progressive muscle weakness, many DMD patients therefore also exhibit intellectual and behavioral abnormalities. The most commonly used mouse model for DMD, the mdx mouse, lacks only the full-length dystrophin isoforms and has been extensively characterized for muscle pathology. In this study, we assessed behavioral effects of a lack of full-length dystrophins on spontaneous behavior, discrimination and reversal learning, anxiety, and short-term spatial memory and compared performance between male and female mdx mice. In contrast to our previous study using only female mdx mice, we could not reproduce the earlier observed reversal learning deficit. However, we did notice small differences in the number of visits made during the Y-maze and dark-light box. Results indicate that it is advisable to establish standard operating procedures specific to behavioral testing in mdx mice to allow the detection of the subtle phenotypic differences and to eliminate inter and intra laboratory variance.
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Affiliation(s)
- Sarah Engelbeen
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
| | | | | | - Maarten Loos
- Sylics (Synaptologics B.V.), Amsterdam, Netherlands
| | - Maaike van Putten
- Department of Human Genetics, Leiden University Medical Center, Leiden, Netherlands
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11
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Arroyo-Araujo M, Graf R, Maco M, van Dam E, Schenker E, Drinkenburg W, Koopmans B, de Boer SF, Cullum-Doyle M, Noldus LPJJ, Loos M, van Dommelen W, Spooren W, Biemans B, Buhl DL, Kas MJ. Reproducibility via coordinated standardization: a multi-center study in a Shank2 genetic rat model for Autism Spectrum Disorders. Sci Rep 2019; 9:11602. [PMID: 31406134 PMCID: PMC6690904 DOI: 10.1038/s41598-019-47981-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/25/2019] [Indexed: 02/01/2023] Open
Abstract
Inconsistent findings between laboratories are hampering scientific progress and are of increasing public concern. Differences in laboratory environment is a known factor contributing to poor reproducibility of findings between research sites, and well-controlled multisite efforts are an important next step to identify the relevant factors needed to reduce variation in study outcome between laboratories. Through harmonization of apparatus, test protocol, and aligned and non-aligned environmental variables, the present study shows that behavioral pharmacological responses in Shank2 knockout (KO) rats, a model of synaptic dysfunction relevant to autism spectrum disorders, were highly replicable across three research centers. All three sites reliably observed a hyperactive and repetitive behavioral phenotype in KO rats compared to their wild-type littermates as well as a dose-dependent phenotype attenuation following acute injections of a selective mGluR1 antagonist. These results show that reproducibility in preclinical studies can be obtained and emphasizes the need for high quality and rigorous methodologies in scientific research. Considering the observed external validity, the present study also suggests mGluR1 as potential target for the treatment of autism spectrum disorders.
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Affiliation(s)
- María Arroyo-Araujo
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Radka Graf
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, MA, USA
| | - Martine Maco
- Roche Innovation Center Basel, Basel, Switzerland
| | - Elsbeth van Dam
- Noldus Information Technology BV, Wageningen, The Netherlands
| | | | | | | | - Sietse F de Boer
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | | | | | - Maarten Loos
- Sylics Synaptologics BV, Amsterdam, The Netherlands
| | | | - Will Spooren
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, MA, USA
| | | | - Derek L Buhl
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, MA, USA
| | - Martien J Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands. .,Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands.
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12
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Guimarães MHD, Koopmans B. Spin Accumulation and Dynamics in Inversion-Symmetric van der Waals Crystals. Phys Rev Lett 2018; 120:266801. [PMID: 30004759 DOI: 10.1103/physrevlett.120.266801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/25/2018] [Indexed: 06/08/2023]
Abstract
Inversion-symmetric materials are forbidden to show an overall spin texture in their band structure in the presence of time-reversal symmetry. However, in van der Waals materials which lack inversion symmetry within a single layer, it has been proposed that a layer-dependent spin texture can arise leading to a coupled spin-layer degree of freedom. Here we use time-resolved Kerr rotation in inversion-symmetric WSe_{2} and MoSe_{2} bulk crystals to study this spin-layer polarization and unveil its dynamics. Our measurements show that the spin-layer relaxation time in WSe_{2} is limited by phonon scattering at high temperatures and that the interlayer hopping can be tuned by a small in-plane magnetic field at low temperatures, enhancing the relaxation rates. We find a significantly lower lifetime for MoSe_{2} which agrees with theoretical expectations of a spin-layer polarization stabilized by the larger spin-orbit coupling in WSe_{2}.
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Affiliation(s)
- M H D Guimarães
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, Netherlands
| | - B Koopmans
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, Netherlands
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13
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Kovačević J, Maroteaux G, Schut D, Loos M, Dubey M, Pitsch J, Remmelink E, Koopmans B, Crowley J, Cornelisse LN, Sullivan PF, Schoch S, Toonen RF, Stiedl O, Verhage M. Protein instability, haploinsufficiency, and cortical hyper-excitability underlie STXBP1 encephalopathy. Brain 2018; 141:1350-1374. [PMID: 29538625 PMCID: PMC5917748 DOI: 10.1093/brain/awy046] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 12/15/2017] [Accepted: 01/05/2018] [Indexed: 01/14/2023] Open
Abstract
De novo heterozygous mutations in STXBP1/Munc18-1 cause early infantile epileptic encephalopathies (EIEE4, OMIM #612164) characterized by infantile epilepsy, developmental delay, intellectual disability, and can include autistic features. We characterized the cellular deficits for an allelic series of seven STXBP1 mutations and developed four mouse models that recapitulate the abnormal EEG activity and cognitive aspects of human STXBP1-encephalopathy. Disease-causing STXBP1 variants supported synaptic transmission to a variable extent on a null background, but had no effect when overexpressed on a heterozygous background. All disease variants had severely decreased protein levels. Together, these cellular studies suggest that impaired protein stability and STXBP1 haploinsufficiency explain STXBP1-encephalopathy and that, therefore, Stxbp1+/- mice provide a valid mouse model. Simultaneous video and EEG recordings revealed that Stxbp1+/- mice with different genomic backgrounds recapitulate the seizure/spasm phenotype observed in humans, characterized by myoclonic jerks and spike-wave discharges that were suppressed by the antiepileptic drug levetiracetam. Mice heterozygous for Stxbp1 in GABAergic neurons only, showed impaired viability, 50% died within 2-3 weeks, and the rest showed stronger epileptic activity. c-Fos staining implicated neocortical areas, but not other brain regions, as the seizure foci. Stxbp1+/- mice showed impaired cognitive performance, hyperactivity and anxiety-like behaviour, without altered social behaviour. Taken together, these data demonstrate the construct, face and predictive validity of Stxbp1+/- mice and point to protein instability, haploinsufficiency and imbalanced excitation in neocortex, as the underlying mechanism of STXBP1-encephalopathy. The mouse models reported here are valid models for development of therapeutic interventions targeting STXBP1-encephalopathy.
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Affiliation(s)
- Jovana Kovačević
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Gregoire Maroteaux
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Desiree Schut
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - Mohit Dubey
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Julika Pitsch
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, 53105 Bonn, Germany
| | | | | | - James Crowley
- UNC Center for Psychiatric Genomics, University of North Carolina at Chapel Hill, 101 Manning Drive, Chapel Hill, NC 27599-7160, USA
| | - L Niels Cornelisse
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Patrick F Sullivan
- UNC Center for Psychiatric Genomics, University of North Carolina at Chapel Hill, 101 Manning Drive, Chapel Hill, NC 27599-7160, USA
- Karolinska Institutet, Department of Medical Epidemiology and Biostatistics and Department of (Clinical) Genetics, Nobels väg 12A, 171 77 Stockholm, Sweden
| | - Susanne Schoch
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, 53105 Bonn, Germany
| | - Ruud F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Oliver Stiedl
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU Medical Center, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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14
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Logan S, Owen D, Chen S, Chen WJ, Ungvari Z, Farley J, Csiszar A, Sharpe A, Loos M, Koopmans B, Richardson A, Sonntag WE. Simultaneous assessment of cognitive function, circadian rhythm, and spontaneous activity in aging mice. GeroScience 2018; 40:123-137. [PMID: 29687240 DOI: 10.1007/s11357-018-0019-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/11/2018] [Indexed: 12/27/2022] Open
Abstract
Cognitive function declines substantially with age in both humans and animal models. In humans, this decline is associated with decreases in independence and quality of life. Although the methodology for analysis of cognitive function in human models is relatively well established, similar analyses in animal models have many technical issues (e.g., unintended experimenter bias, motivational issues, stress, and testing during the light phase of the light dark cycle) that limit interpretation of the results. These caveats, and others, potentially bias the interpretation of studies in rodents and prevent the application of current tests of learning and memory as part of an overall healthspan assessment in rodent models of aging. The goal of this study was to establish the methodology to assess cognitive function in aging animals that addresses many of these concerns. Here, we use a food reward-based discrimination procedure with minimal stress in C57Bl/6J male mice at 6, 21, and 27 months of age, followed by a reversal task to assess behavioral flexibility. Importantly, the procedures minimize issues related to between-experimenter confounds and are conducted during both the dark and light phases of the light dark cycle in a home-cage setting. During cognitive testing, we were able to assess multiple measures of spontaneous movement and diurnal activity in young and aged mice including, distance moved, velocity, and acceleration over a 90-h period. Both initial discrimination and reversal learning significantly decreased with age and, similar to rats and humans, not all old mice demonstrated impairments in learning with age. These results permitted classification of animals based on their cognitive status. Analysis of movement parameters indicated decreases in distance moved as well as velocity and acceleration with increasing age. Based on these data, we developed preliminary models indicating, as in humans, a close relationship exists between age-related movement parameters and cognitive ability. Our results provide a reliable method for assessing cognitive performance with minimal stress and simultaneously provide key information on movement and diurnal activity. These methods represent a novel approach to developing non-invasive healthspan measures in rodent models that allow standardization across laboratories.
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Affiliation(s)
- Sreemathi Logan
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA.
| | - Daniel Owen
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
| | - Sixia Chen
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Wei-Jen Chen
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zoltan Ungvari
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
| | - Julie Farley
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
| | - Amanda Sharpe
- College of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | | | - Arlan Richardson
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
| | - William E Sonntag
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10TH Street, SLY-BRC 1303, Oklahoma City, OK, 73104, USA
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15
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Marchisella E, Wijnands R, Koopmans B, Spijker S, Loos M. Constitutive loss and acute pharmacological manipulation of ErbB4 signaling do not affect attention and inhibitory control in mice. Genes Brain Behav 2017; 17:56-69. [PMID: 28792672 DOI: 10.1111/gbb.12402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/30/2017] [Accepted: 07/19/2017] [Indexed: 02/03/2023]
Abstract
The receptor tyrosine kinase ErbB4 and its ligand trophic factors of the neuregulin (NRG) family have been associated with schizophrenia and other mental disorders in human genetic studies. In vivo studies in mice have shown how abnormal Nrg-ErbB4 signaling leads to deviant behaviors relevant to distinct aspects of schizophrenia, including hyperactivity, sensory gating deficits, working and spatial memory deficits and impaired social behavior. However, so far little is known on the role of ErbB4 in attention and inhibitory control, two aspects of executive functions that are impaired in schizophrenia. Here we investigated the effects of constitutive loss of ErbB4 in the central nervous system of mice on performance in a 5-choice serial reaction time task (5CSRTT) assessing attention and inhibitory control. In this task, ErbB4-/- mice did not show deficits in various parameters of attention, and premature responses as measure of inhibitory control. Nonetheless, ErbB4-/- mice recapitulated a specific set of behavioral phenotypes associated with schizophrenia, including a deficit in spatial learning and memory in the Barnes Maze and in contextual fear learning, and a trend for a deficit in sensorimotor gating. Furthermore, we investigated the effect of acute pharmacological inhibition of ErbB tyrosine kinase receptor using the pan-ErbB kinase inhibitor JNJ-28871063 (JNJ), in an automated version of the 5CSRTT. JNJ did not affect attention and inhibitory control. In conclusion, our data suggest no direct involvement of a classical Nrg-ErbB4 pathway in attention and inhibitory control in mice, while it confirms the involvement of this pathway in other domains relevant to schizophrenia.
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Affiliation(s)
| | | | | | - S Spijker
- Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive research, Neuroscience Campus Amsterdam, VU University, De Boelelaan, The Netherlands
| | - M Loos
- Sylics (Synaptologics B.V.), Amsterdam.,Department of Molecular & Cellular Neurobiology, Center for Neurogenomics and Cognitive research, Neuroscience Campus Amsterdam, VU University, De Boelelaan, The Netherlands
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16
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Stoll T, Zafeiropoulos G, Dogan I, Genuit H, Lavrijsen R, Koopmans B, Tsampas M. Visible-light-promoted gas-phase water splitting using porous WO 3 /BiVO 4 photoanodes. Electrochem commun 2017. [DOI: 10.1016/j.elecom.2017.07.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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17
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Koopmans B, Smit AB, Verhage M, Loos M. AHCODA-DB: a data repository with web-based mining tools for the analysis of automated high-content mouse phenomics data. BMC Bioinformatics 2017; 18:200. [PMID: 28376796 PMCID: PMC5379645 DOI: 10.1186/s12859-017-1612-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 03/24/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Systematic, standardized and in-depth phenotyping and data analyses of rodent behaviour empowers gene-function studies, drug testing and therapy design. However, no data repositories are currently available for standardized quality control, data analysis and mining at the resolution of individual mice. DESCRIPTION Here, we present AHCODA-DB, a public data repository with standardized quality control and exclusion criteria aimed to enhance robustness of data, enabled with web-based mining tools for the analysis of individually and group-wise collected mouse phenotypic data. AHCODA-DB allows monitoring in vivo effects of compounds collected from conventional behavioural tests and from automated home-cage experiments assessing spontaneous behaviour, anxiety and cognition without human interference. AHCODA-DB includes such data from mutant mice (transgenics, knock-out, knock-in), (recombinant) inbred strains, and compound effects in wildtype mice and disease models. AHCODA-DB provides real time statistical analyses with single mouse resolution and versatile suite of data presentation tools. On March 9th, 2017 AHCODA-DB contained 650 k data points on 2419 parameters from 1563 mice. CONCLUSION AHCODA-DB provides users with tools to systematically explore mouse behavioural data, both with positive and negative outcome, published and unpublished, across time and experiments with single mouse resolution. The standardized (automated) experimental settings and the large current dataset (1563 mice) in AHCODA-DB provide a unique framework for the interpretation of behavioural data and drug effects. The use of common ontologies allows data export to other databases such as the Mouse Phenome Database. Unbiased presentation of positive and negative data obtained under the highly standardized screening conditions increase cost efficiency of publicly funded mouse screening projects and help to reach consensus conclusions on drug responses and mouse behavioural phenotypes. The website is publicly accessible through https://public.sylics.com and can be viewed in every recent version of all commonly used browsers.
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Affiliation(s)
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Amsterdam Neuroscience, VU University Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, VU Medical Center, Amsterdam, The Netherlands
| | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
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18
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Bergeard N, Hehn M, Mangin S, Lengaigne G, Montaigne F, Lalieu MLM, Koopmans B, Malinowski G. Hot-Electron-Induced Ultrafast Demagnetization in Co/Pt Multilayers. Phys Rev Lett 2016; 117:147203. [PMID: 27740830 DOI: 10.1103/physrevlett.117.147203] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Indexed: 05/23/2023]
Abstract
Using specially engineered structures to tailor the optical absorption in a metallic multilayer, we analyze the magnetization dynamics of a Co/Pt multilayer buried below a thick Cu layer. We demonstrate that hot electrons alone can very efficiently induce ultrafast demagnetization. Simulations based on hot electron ballistic transport implemented within a microscopic model that accounts for local dissipation of angular momentum nicely reproduce the experimental results, ruling out contribution of pure thermal transport.
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Affiliation(s)
- N Bergeard
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
| | - M Hehn
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
| | - S Mangin
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
| | - G Lengaigne
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
| | - F Montaigne
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
| | - M L M Lalieu
- Department of Applied Physics, center for NanoMaterials (cNM) Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - B Koopmans
- Department of Applied Physics, center for NanoMaterials (cNM) Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - G Malinowski
- Institut Jean Lamour, CNRS UMR 7198, Universitè de Lorraine, 54506 Vandoeuvre-lès-Nancy, France
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19
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Sharma N, van Mourik RA, Yin Y, Koopmans B, Parkin SSP. Focused-electron-beam-induced-deposited cobalt nanopillars for nanomagnetic logic. Nanotechnology 2016; 27:165301. [PMID: 26941232 DOI: 10.1088/0957-4484/27/16/165301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Nanomagnetic logic (NML) intends to alleviate problems of continued miniaturization of CMOS-based electronics, such as energy dissipation through heat, through advantages such as low power operation and non-volatile magnetic elements. In line with recent breakthroughs in NML with perpendicularly magnetized elements formed from thin films, we have fabricated NML inverter chains from Co nanopillars by focused electron beam induced deposition (FEBID) that exhibit shape-induced perpendicular magnetization. The flexibility of FEBID allows optimization of NML structures. Simulations reveal that the choice of nanopillar dimensions is critical to obtain the correct antiferromagnetically coupled configuration. Experiments carrying the array through a clocking cycle using the Oersted field from an integrated Cu wire show that the array responds to the clocking cycle.
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Affiliation(s)
- N Sharma
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands
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20
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van den Brink A, Vermijs G, Solignac A, Koo J, Kohlhepp JT, Swagten HJM, Koopmans B. Field-free magnetization reversal by spin-Hall effect and exchange bias. Nat Commun 2016; 7:10854. [PMID: 26940861 PMCID: PMC5411711 DOI: 10.1038/ncomms10854] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/27/2016] [Indexed: 11/09/2022] Open
Abstract
As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin–orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface. Future information storage technology may exploit electrical currents to write the states of ferromagnetic nanoelements via spin torque effects. Here, the authors demonstrate such behaviour promoted by exchange bias from an interfaced antiferromagnet, which may help overcome practical device limitations.
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Affiliation(s)
- A van den Brink
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
| | - G Vermijs
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
| | - A Solignac
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands.,SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191 Gif-sur-Yvette, France
| | - J Koo
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
| | - J T Kohlhepp
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
| | - H J M Swagten
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
| | - B Koopmans
- Eindhoven University of Technology, PO Box 513, Noord-Brabant, 5600 MB Eindhoven, The Netherlands
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21
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Córdoba R, Barcones B, Roelfsema E, Verheijen MA, Mulders JJL, Trompenaars PHF, Koopmans B. Functional nickel-based deposits synthesized by focused beam induced processing. Nanotechnology 2016; 27:065303. [PMID: 26759183 DOI: 10.1088/0957-4484/27/6/065303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Functional nanostructures fabricated by focused electron/ion beam induced processing (FEBIP/FIBIP) open a promising route for applications in nanoelectronics. Such developments rely on the exploration of new advanced materials. We report here the successful fabrication of nickel-based deposits by FEBIP/FIBIP using bis(methyl cyclopentadienyl)nickel as a precursor. In particular, binary compounds such as nickel oxide (NiO) are synthesized by using an in situ two-step process at room temperature. By this method, as-grown Ni deposits transform into homogeneous NiO deposits using focused electron beam irradiation under O2 flux. This procedure is effective in producing highly pure NiO deposits with resistivity of 2000 Ωcm and a polycrystalline structure with face-centred cubic lattice and grains of 5 nm. We demonstrate that systems based on NiO deposits displaying resistance switching and an exchange-bias effect could be grown by FEBIP using optimized parameters. Our results provide a breakthrough towards using these techniques for the fabrication of functional nanodevices.
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Affiliation(s)
- R Córdoba
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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22
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Abstract
We introduce an alternative type of probe for scanning tunneling microscopy (STM). Instead of using a needle-like tip made from a piece of metallic wire, a sharp-edged cleaved insulating substrate, which is initially covered by a thin conductive film, is used. The sharp tip is formed at the intersection of the two cleaved sides. Using this approach a variety of materials for STM probes can be used, and functionalization of STM probes is possible. The working principle of different probes made of metallic (Pt, Co, and CoB), indium-tin oxide, as well as Cu/Pt and Co/Pt multilayer films are demonstrated by STM imaging of clean Cu(001) and Cu(111) surfaces as well as the epitaxial Co clusters on Cu(111).
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Affiliation(s)
- T Siahaan
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB, The Netherlands
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23
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Bruining H, Matsui A, Oguro-Ando A, Kahn RS, Van't Spijker HM, Akkermans G, Stiedl O, van Engeland H, Koopmans B, van Lith HA, Oppelaar H, Tieland L, Nonkes LJ, Yagi T, Kaneko R, Burbach JPH, Yamamoto N, Kas MJ. Genetic Mapping in Mice Reveals the Involvement of Pcdh9 in Long-Term Social and Object Recognition and Sensorimotor Development. Biol Psychiatry 2015; 78:485-95. [PMID: 25802080 DOI: 10.1016/j.biopsych.2015.01.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 01/09/2015] [Accepted: 01/13/2015] [Indexed: 01/12/2023]
Abstract
BACKGROUND Quantitative genetic analysis of basic mouse behaviors is a powerful tool to identify novel genetic phenotypes contributing to neurobehavioral disorders. Here, we analyzed genetic contributions to single-trial, long-term social and nonsocial recognition and subsequently studied the functional impact of an identified candidate gene on behavioral development. METHODS Genetic mapping of single-trial social recognition was performed in chromosome substitution strains, a sophisticated tool for detecting quantitative trait loci (QTL) of complex traits. Follow-up occurred by generating and testing knockout (KO) mice of a selected QTL candidate gene. Functional characterization of these mice was performed through behavioral and neurological assessments across developmental stages and analyses of gene expression and brain morphology. RESULTS Chromosome substitution strain 14 mapping studies revealed an overlapping QTL related to long-term social and object recognition harboring Pcdh9, a cell-adhesion gene previously associated with autism spectrum disorder. Specific long-term social and object recognition deficits were confirmed in homozygous (KO) Pcdh9-deficient mice, while heterozygous mice only showed long-term social recognition impairment. The recognition deficits in KO mice were not associated with alterations in perception, multi-trial discrimination learning, sociability, behavioral flexibility, or fear memory. Rather, KO mice showed additional impairments in sensorimotor development reflected by early touch-evoked biting, rotarod performance, and sensory gating deficits. This profile emerged with structural changes in deep layers of sensory cortices, where Pcdh9 is selectively expressed. CONCLUSIONS This behavior-to-gene study implicates Pcdh9 in cognitive functions required for long-term social and nonsocial recognition. This role is supported by the involvement of Pcdh9 in sensory cortex development and sensorimotor phenotypes.
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Affiliation(s)
- Hilgo Bruining
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Asuka Matsui
- Neuroscience Laboratories, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Asami Oguro-Ando
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - René S Kahn
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Heleen M Van't Spijker
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Guus Akkermans
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Oliver Stiedl
- Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam
| | - Herman van Engeland
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Hein A van Lith
- Division of Animal Welfare & Laboratory Animal Science, Department of Animals in Science and Society, Program Emotion and Cognition, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
| | - Hugo Oppelaar
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Liselotte Tieland
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Lourens J Nonkes
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Takeshi Yagi
- KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Ryosuke Kaneko
- KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - J Peter H Burbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Nobuhiko Yamamoto
- Neuroscience Laboratories, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Martien J Kas
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
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Loos M, Koopmans B, Aarts E, Maroteaux G, van der Sluis S, Verhage M, Smit AB. Within-strain variation in behavior differs consistently between common inbred strains of mice. Mamm Genome 2015; 26:348-54. [DOI: 10.1007/s00335-015-9578-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/17/2015] [Indexed: 12/31/2022]
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25
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Giniatullina A, Maroteaux G, Geerts CJ, Koopmans B, Loos M, Klaassen R, Chen N, van der Schors RC, van Nierop P, Li KW, de Jong J, Altrock WD, Cornelisse LN, Toonen RF, van der Sluis S, Sullivan PF, Stiedl O, Posthuma D, Smit AB, Groffen AJ, Verhage M. Functional characterization of the PCLO p.Ser4814Ala variant associated with major depressive disorder reveals cellular but not behavioral differences. Neuroscience 2015; 300:518-38. [PMID: 26045179 DOI: 10.1016/j.neuroscience.2015.05.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 05/17/2015] [Accepted: 05/20/2015] [Indexed: 12/14/2022]
Abstract
Genome-wide association studies have suggested a role for a genetic variation in the presynaptic gene PCLO in major depressive disorder (MDD). As with many complex traits, the PCLO variant has a small contribution to the overall heritability and the association does not always replicate. One variant (rs2522833, p.Ser4814Ala) is of particular interest given that it is a common, nonsynonymous exon variant near a calcium-sensing part of PCLO. It has been suggested that the molecular effects of such variations penetrate to a variable extent in the population due to phenotypic and genotypic heterogeneity at the population level. More robust effects may be exposed by studying such variations in isolation, in a more homogeneous context. We tested this idea by modeling PCLO variation in a mouse knock-in model expressing the Pclo(SA)(/)(SA) variant. In the highly homogeneous background of inbred mice, two functional effects of the SA-variation were observed at the cellular level: increased synaptic Piccolo levels, and 30% increased excitatory synaptic transmission in cultured neurons. Other aspects of Piccolo function were unaltered: calcium-dependent phospholipid binding, synapse formation in vitro, and synaptic accumulation of synaptic vesicles. Moreover, anxiety, cognition and depressive-like behavior were normal in Pclo(SA)(/)(SA) mice. We conclude that the PCLO p.Ser4814Ala missense variant produces mild cellular phenotypes, which do not translate into behavioral phenotypes. We propose a model explaining how (subtle) cellular phenotypes do not penetrate to the mouse behavioral level but, due to genetic and phenotypic heterogeneity and non-linearity, can produce association signals in human population studies.
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Affiliation(s)
- A Giniatullina
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - G Maroteaux
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - C J Geerts
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - B Koopmans
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - M Loos
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
| | - R Klaassen
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - N Chen
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - R C van der Schors
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - P van Nierop
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - K W Li
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - J de Jong
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - W D Altrock
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - L N Cornelisse
- Department of Clinical Genetics, Section Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - R F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - S van der Sluis
- Department of Clinical Genetics, Section Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands
| | - P F Sullivan
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - O Stiedl
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands; Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - D Posthuma
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - A B Smit
- Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands
| | - A J Groffen
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - M Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam, The Netherlands; Department of Clinical Genetics, Section Complex Trait Genetics, VU University Medical Center, Amsterdam, The Netherlands.
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26
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Remmelink E, Loos M, Koopmans B, Aarts E, van der Sluis S, Smit AB, Verhage M. A 1-night operant learning task without food-restriction differentiates among mouse strains in an automated home-cage environment. Behav Brain Res 2015; 283:53-60. [PMID: 25601577 DOI: 10.1016/j.bbr.2015.01.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/08/2015] [Accepted: 01/10/2015] [Indexed: 11/18/2022]
Abstract
Individuals are able to change their behavior based on its consequences, a process involving instrumental learning. Studying instrumental learning in mice can provide new insights in this elementary aspect of cognition. Conventional appetitive operant learning tasks that facilitate the study of this form of learning in mice, as well as more complex operant paradigms, require labor-intensive handling and food deprivation to motivate the animals. Here, we describe a 1-night operant learning protocol that exploits the advantages of automated home-cage testing and circumvents the interfering effects of food restriction. The task builds on behavior that is part of the spontaneous exploratory repertoire during the days before the task. We compared the behavior of C57BL/6J, BALB/cJ and DBA/2J mice and found various differences in behavior during this task, but no differences in learning curves. BALB/cJ mice showed the largest instrumental learning response, providing a superior dynamic range and statistical power to study instrumental learning by using this protocol. Insights gained with this home-cage-based learning protocol without food restriction will be valuable for the development of other, more complex, cognitive tasks in automated home-cages.
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Affiliation(s)
- Esther Remmelink
- Sylics (Synaptologics B.V.), Amsterdam, The Netherlands; Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands; Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Maarten Loos
- Sylics (Synaptologics B.V.), Amsterdam, The Netherlands.
| | | | - Emmeke Aarts
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Sophie van der Sluis
- Section Complex Trait Genetics, Department of Clinical Genetics, VU Medical Center, Amsterdam, The Netherlands
| | | | - Matthijs Verhage
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
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27
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Sharma N, Vugts P, Daniels C, Keuning W, Kohlhepp JT, Kurnosikov O, Koopmans B. Multi-channel Andreev reflection in Co-W nanocontacts fabricated using focused electron/ion beam induced deposition. Nanotechnology 2014; 25:495201. [PMID: 25409909 DOI: 10.1088/0957-4484/25/49/495201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report multi-channel electron transport in nano-contacts fabricated using focused electron beam induced deposited (FEBID) cobalt and focused ion beam induced deposited (FIBID) tungsten. Anomalous Andreev reflection (AR) effect is observed to which the conventional Blonder-Tinkham-Klapwijk (BTK) fit cannot be applied. In specific, we have observed multiple number of shoulders near the AR peak, whose origin is unknown in literature. We explain this effect based on a simple model that takes into account the material properties of the FIBID grown W superconductor, as well as the specific interface properties that are an outcome of using FEBID/FIBID as a fabrication technique. We show that numerical calculations using the BTK approximation based on the consideration of multiple channels generate similar shoulders as we observed in the AR experiments. Electrical measurements and x-ray photoemission spectroscopy carried out on FIBID W deposits puts additional evidence towards multi-channel current transport occuring at the interface of the nanocontacts.
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Affiliation(s)
- N Sharma
- Department of Applied Physics, Center for NanoMaterials and COBRA Research Institute, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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28
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Loos M, Koopmans B, Aarts E, Maroteaux G, van der Sluis S, Verhage M, Smit AB. Sheltering behavior and locomotor activity in 11 genetically diverse common inbred mouse strains using home-cage monitoring. PLoS One 2014; 9:e108563. [PMID: 25264768 PMCID: PMC4180925 DOI: 10.1371/journal.pone.0108563] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 08/22/2014] [Indexed: 11/26/2022] Open
Abstract
Functional genetic analyses in mice rely on efficient and in-depth characterization of the behavioral spectrum. Automated home-cage observation can provide a systematic and efficient screening method to detect unexplored, novel behavioral phenotypes. Here, we analyzed high-throughput automated home-cage data using existing and novel concepts, to detect a plethora of genetic differences in spontaneous behavior in a panel of commonly used inbred strains (129S1/SvImJ, A/J, C3H/HeJ, C57BL/6J, BALB/cJ, DBA/2J, NOD/LtJ, FVB/NJ, WSB/EiJ, PWK/PhJ and CAST/EiJ). Continuous video-tracking observations of sheltering behavior and locomotor activity were segmented into distinguishable behavioral elements, and studied at different time scales, yielding a set of 115 behavioral parameters of which 105 showed highly significant strain differences. This set of 115 parameters was highly dimensional; principal component analysis identified 26 orthogonal components with eigenvalues above one. Especially novel parameters of sheltering behavior and parameters describing aspects of motion of the mouse in the home-cage showed high genetic effect sizes. Multi-day habituation curves and patterns of behavior surrounding dark/light phase transitions showed striking strain differences, albeit with lower genetic effect sizes. This spontaneous home-cage behavior study demonstrates high dimensionality, with a strong genetic contribution to specific sets of behavioral measures. Importantly, spontaneous home-cage behavior analysis detects genetic effects that cannot be studied in conventional behavioral tests, showing that the inclusion of a few days of undisturbed, labor extensive home-cage assessment may greatly aid gene function analyses and drug target discovery.
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Affiliation(s)
- Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, The Netherlands
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
- * E-mail:
| | | | - Emmeke Aarts
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
| | - Gregoire Maroteaux
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
| | - Sophie van der Sluis
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
- Section Complex Trait Genetics, Department of Clinical Genetics, VU Medical Center, Amsterdam, The Netherlands
| | | | - Matthijs Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
- Department of Clinical Genetics, VU Medical Center, Amsterdam, The Netherlands
| | - August B. Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, The Netherlands
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29
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Schellekens AJ, Kuiper KC, de Wit RRJC, Koopmans B. Ultrafast spin-transfer torque driven by femtosecond pulsed-laser excitation. Nat Commun 2014; 5:4333. [PMID: 25007881 DOI: 10.1038/ncomms5333] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 06/06/2014] [Indexed: 11/09/2022] Open
Abstract
Spin currents have an important role in many proposed spintronic devices, as they govern the switching process of magnetic bits in random access memories or drive domain wall motion in magnetic shift registers. The generation of these spin currents has to be fast and energy efficient for realization of these envisioned devices. Recently it has been shown that femtosecond pulsed-laser excitation of thin magnetic films creates intense and ultrafast spin currents. Here we utilize this method to change the orientation of the magnetization in a magnetic bilayer by spin-transfer torque on sub-picosecond timescales. By analysing the dynamics of the magnetic bilayer after laser excitation, the rich physics governing ultrafast spin-transfer torque are elucidated opening up new pathways to ultrafast magnetization reversal, but also providing a new method to quantify optically induced spin currents generated on femtosecond timescales.
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Affiliation(s)
- A J Schellekens
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - K C Kuiper
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - R R J C de Wit
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - B Koopmans
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
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30
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Janssen P, Cox M, Wouters S, Kemerink M, Wienk M, Koopmans B. Tuning organic magnetoresistance in polymer-fullerene blends by controlling spin reaction pathways. Nat Commun 2013; 4:2286. [DOI: 10.1038/ncomms3286] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 07/10/2013] [Indexed: 11/09/2022] Open
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31
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Schellekens AJ, Koopmans B. Comparing ultrafast demagnetization rates between competing models for finite temperature magnetism. Phys Rev Lett 2013; 110:217204. [PMID: 23745920 DOI: 10.1103/physrevlett.110.217204] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Indexed: 06/02/2023]
Abstract
We investigate a recent controversy in ultrafast magnetization dynamics by comparing the demagnetization rates from two frequently used but competing descriptions for finite temperature magnetism, namely a rigid band structure Stoner-like approach and a system of localized spins. The calculations on the localized spin system show a demagnetization rate and time comparable to experimentally obtained values, whereas the rigid band approach yields negligible demagnetization, even when the microscopic spin-flip process is assumed to be instantaneous. This shows that rigid band structure calculations will never be in quantitative agreement with experiments, irrespective of the investigated microscopic scattering mechanism.
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Affiliation(s)
- A J Schellekens
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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32
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Haazen PPJ, Murè E, Franken JH, Lavrijsen R, Swagten HJM, Koopmans B. Domain wall depinning governed by the spin Hall effect. Nat Mater 2013; 12:299-303. [PMID: 23377291 DOI: 10.1038/nmat3553] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 12/17/2012] [Indexed: 05/12/2023]
Abstract
Perpendicularly magnetized materials have attracted significant interest owing to their high anisotropy, which gives rise to extremely narrow, nanosized domain walls. As a result, the recently studied current-induced domain wall motion (CIDWM) in these materials promises to enable a new class of data, memory and logic devices. Here we propose the spin Hall effect as an alternative mechanism for CIDWM. We are able to carefully tune the net spin Hall current in depinning experiments on Pt/Co/Pt nanowires, offering unique control over CIDWM. Furthermore, we determine that the depinning efficiency is intimately related to the internal structure of the domain wall, which we control by the application of small fields along the nanowire. This manifestation of CIDWM offers an attractive degree of freedom for manipulating domain wall motion by charge currents, and sheds light on the existence of contradicting reports on CIDWM in perpendicularly magnetized materials.
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Affiliation(s)
- P P J Haazen
- Department of Applied Physics, Center for NanoMaterials and COBRA Research Institute, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Maroteaux G, Loos M, van der Sluis S, Koopmans B, Aarts E, van Gassen K, Geurts A, Largaespada DA, Spruijt BM, Stiedl O, Smit AB, Verhage M. High-throughput phenotyping of avoidance learning in mice discriminates different genotypes and identifies a novel gene. Genes Brain Behav 2012; 11:772-84. [PMID: 22846151 DOI: 10.1111/j.1601-183x.2012.00820.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/27/2012] [Accepted: 07/03/2012] [Indexed: 01/31/2023]
Abstract
Recognizing and avoiding aversive situations are central aspects of mammalian cognition. These abilities are essential for health and survival and are expected to have a prominent genetic basis. We modeled these abilities in eight common mouse inbred strains covering ∼75% of the species' natural variation and in gene-trap mice (>2000 mice), using an unsupervised, automated assay with an instrumented home cage (PhenoTyper) containing a shelter with two entrances. Mice visited this shelter for 20-1200 times/24 h and 71% of all mice developed a significant and often strong preference for one entrance. Subsequently, a mild aversive stimulus (shelter illumination) was automatically delivered when mice used their preferred entrance. Different genotypes developed different coping strategies. Firstly, the number of entries via the preferred entrance decreased in DBA/2J, C57BL/6J and 129S1/SvImJ, indicating that these genotypes associated one specific entrance with the aversive stimulus. Secondly, mice started sleeping outside (C57BL/6J, DBA/2J), indicating they associated the shelter, in general, with the aversive stimulus. Some mice showed no evidence for an association between the entrance and the aversive light, but did show markedly shorter shelter residence times in response to illumination, indicating they did perceive illumination as aversive. Finally, using this assay, we screened 43 different mutants, which yielded a novel gene, specc1/cytospinB. This mutant showed profound and specific delay in avoidance learning. Together, these data suggest that different genotypes express distinct learning and/or memory of associations between shelter entrance and aversive stimuli, and that specc1/cytospinB is involved in this aspect of cognition.
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Affiliation(s)
- G Maroteaux
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University Amsterdam and VU Medical Center, Amsterdam, The Netherlands
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Franken JH, Swagten HJM, Koopmans B. Shift registers based on magnetic domain wall ratchets with perpendicular anisotropy. Nat Nanotechnol 2012; 7:499-503. [PMID: 22796743 DOI: 10.1038/nnano.2012.111] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 06/01/2012] [Indexed: 06/01/2023]
Abstract
The movement of magnetic domain walls can be used to build a device known as a shift register, which has applications in memory and logic circuits. However, the application of magnetic domain wall shift registers has been hindered by geometrical restrictions, by randomness in domain wall displacement and by the need for high current densities or rotating magnetic fields. Here, we propose a new approach in which the energy landscape experienced by the domain walls is engineered to favour a unidirectional ratchet-like propagation. The domain walls are defined between domains with an out-of-plane (perpendicular) magnetization, which allows us to route domain walls along arbitrary in-plane paths using a time-varying applied magnetic field with fixed orientation. In addition, this ratchet-like motion causes the domain walls to lock to discrete positions along these paths, which is useful for digital devices. As a proof-of-principle experiment we demonstrate the continuous propagation of two domain walls along a closed-loop path in a platinum/cobalt/platinum strip.
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Affiliation(s)
- J H Franken
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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Franken JH, Hoeijmakers M, Swagten HJM, Koopmans B. Tunable resistivity of individual magnetic domain walls. Phys Rev Lett 2012; 108:037205. [PMID: 22400781 DOI: 10.1103/physrevlett.108.037205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Indexed: 05/31/2023]
Abstract
Despite the relevance of current-induced magnetic domain wall (DW) motion for new spintronics applications, the exact details of the current-domain wall interaction are not yet understood. A property intimately related to this interaction is the intrinsic DW resistivity. Here, we investigate experimentally how the resistivity inside a DW depends on the wall width Δ, which is tuned using focused ion beam irradiation of Pt/Co/Pt strips. We observe the nucleation of individual DWs with Kerr microscopy, and measure resistance changes in real time. A 1/Δ(2) dependence of DW resistivity is found, compatible with Levy-Zhang theory. Also quantitative agreement with theory is found by taking full account of the current flowing through each individual layer inside the multilayer stack.
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Affiliation(s)
- J H Franken
- Department of Applied Physics, Center for NanoMaterials and COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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Heinen J, Hinzke D, Boulle O, Malinowski G, Swagten HJM, Koopmans B, Ulysse C, Faini G, Ocker B, Wrona J, Kläui M. Determination of the spin torque non-adiabaticity in perpendicularly magnetized nanowires. J Phys Condens Matter 2012; 24:024220. [PMID: 22172802 DOI: 10.1088/0953-8984/24/2/024220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Novel nanofabrication methods and the discovery of an efficient manipulation of local magnetization based on spin polarized currents has generated a tremendous interest in the field of spintronics. The search for materials allowing for fast domain wall dynamics requires fundamental research into the effects involved (Oersted fields, adiabatic and non-adiabatic spin torque, Joule heating) and possibilities for a quantitative comparison. Theoretical descriptions reveal a material and geometry dependence of the non-adiabaticity factor β, which governs the domain wall velocity. Here, we present two independent approaches for determining β: (i) measuring the dependence of the dwell times for which a domain wall stays in a metastable pinning state on the injected current and (ii) the current-field equivalence approach. The comparison of the deduced β values highlights the problems of using one-dimensional models to describe two-dimensional dynamics and allows us to ascertain the reliability, robustness and limits of the approaches used.
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Affiliation(s)
- J Heinen
- Fachbereich Physik, Universität Konstanz, Konstanz, Germany
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37
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Kersten SP, Schellekens AJ, Koopmans B, Bobbert PA. Magnetic-field dependence of the electroluminescence of organic light-emitting diodes: a competition between exciton formation and spin mixing. Phys Rev Lett 2011; 106:197402. [PMID: 21668199 DOI: 10.1103/physrevlett.106.197402] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Indexed: 05/30/2023]
Abstract
We explore the magnetoelectroluminescence (MEL) of organic light-emitting diodes by evaluating the magnetic-field dependent fraction of singlet excitons formed. We use two- and multisite polaron-hopping models with spin mixing by hyperfine fields and different singlet and triplet exciton formation rates k(S) and k(T). A huge MEL is predicted when exciton formation is in competition with spin mixing and when k(T) is significantly larger than k(S). This competition also leads to a low-field structure in the MEL that is in agreement with recent experiments.
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Affiliation(s)
- S P Kersten
- Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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Kurnosikov O, Swagten HJM, Koopmans B. Internal electron diffraction from atomically ordered subsurface nanostructures in metals. Phys Rev Lett 2011; 106:196803. [PMID: 21668187 DOI: 10.1103/physrevlett.106.196803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 03/01/2011] [Indexed: 05/30/2023]
Abstract
We demonstrate that a part of interface at a subsurface nanocavity in Cu(110) can efficiently induce electron scattering back to the surface even if it is inclined with respect to the surface, if the condition for electron diffraction is fulfilled. This backscattering induces oscillations of electron local density of states at the surface versus electron energy. In agreement with our model calculations, the diffraction is assigned to a specific atomic structure at the interface, and is found to be significantly enhanced by focussing of electron waves for propagation along the [110] direction.
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Affiliation(s)
- O Kurnosikov
- Department of Applied Physics, cNM, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
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Wagemans W, Schellekens AJ, Kemper M, Bloom FL, Bobbert PA, Koopmans B. Spin-spin interactions in organic magnetoresistance probed by angle-dependent measurements. Phys Rev Lett 2011; 106:196802. [PMID: 21668186 DOI: 10.1103/physrevlett.106.196802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Indexed: 05/30/2023]
Abstract
The dependence of organic magnetoresistance (OMAR) on the orientation of the magnetic field has been investigated. In contrast with previous claims, a finite and systematic change in magnitude is observed when the orientation of the field is changed with respect to the sample. It is demonstrated that, to explain these effects, spin-spin interactions have to be included in the models previously suggested for OMAR. Dipole coupling and exchange coupling are introduced in combination with either an anisotropy of the orientation of the spin pairs or an anisotropy in the hyperfine fields.
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Affiliation(s)
- W Wagemans
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Lavrijsen R, Córdoba R, Schoenaker FJ, Ellis TH, Barcones B, Kohlhepp JT, Swagten HJM, Koopmans B, De Teresa JM, Magén C, Ibarra MR, Trompenaars P, Mulders JJL. Fe:O:C grown by focused-electron-beam-induced deposition: magnetic and electric properties. Nanotechnology 2011; 22:025302. [PMID: 21135470 DOI: 10.1088/0957-4484/22/2/025302] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We systematically study the effect of oxygen content on the magneto-transport and microstructure of Fe:O:C nanowires deposited by focused-electron-beam-induced (FEBID) deposition. The Fe/O ratio can be varied with an Fe content varying between ∼ 50 and 80 at.% with overall low C content (≈16 ± 3 at.%) by adding H(2)O during the deposition while keeping the beam parameters constant as measured by energy dispersive x-ray (EDX) spectroscopy. The room-temperature magnetic properties for deposits with an Fe content of 66-71 at.% are investigated using the magneto-optical Kerr effect (MOKE) and electric magneto-transport measurements. The nanostructure of the deposits is investigated through cross-sectional high-resolution transmission electron microscopy (HRTEM) imaging, allowing us to link the observed magneto-resistance and resistivity to the transport mechanism in the deposits. These results demonstrate that functional magnetic nanostructures can be created, paving the way for new magnetic or even spintronics devices.
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Affiliation(s)
- R Lavrijsen
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
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Koopmans B, Malinowski G, Dalla Longa F, Steiauf D, Fähnle M, Roth T, Cinchetti M, Aeschlimann M. Explaining the paradoxical diversity of ultrafast laser-induced demagnetization. Nat Mater 2010; 9:259-65. [PMID: 20010830 DOI: 10.1038/nmat2593] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 11/03/2009] [Indexed: 05/22/2023]
Abstract
Pulsed-laser-induced quenching of ferromagnetic order has intrigued researchers since pioneering works in the 1990s. It was reported that demagnetization in gadolinium proceeds within 100 ps, but three orders of magnitude faster in ferromagnetic transition metals such as nickel. Here we show that a model based on electron-phonon-mediated spin-flip scattering explains both timescales on equal footing. Our interpretation is supported by ab initio estimates of the spin-flip scattering probability, and experimental fluence dependencies are shown to agree perfectly with predictions. A phase diagram is constructed in which two classes of laser-induced magnetization dynamics can be distinguished, where the ratio of the Curie temperature to the atomic magnetic moment turns out to have a crucial role. We conclude that the ultrafast magnetization dynamics can be well described disregarding highly excited electronic states, merely considering the thermalized electron system.
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Affiliation(s)
- B Koopmans
- Department of Applied Physics, Center for NanoMaterials (cNM), Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
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Schoonus JJHM, Lumens PGE, Wagemans W, Kohlhepp JT, Bobbert PA, Swagten HJM, Koopmans B. Magnetoresistance in hybrid organic spin valves at the onset of multiple-step tunneling. Phys Rev Lett 2009; 103:146601. [PMID: 19905590 DOI: 10.1103/physrevlett.103.146601] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Indexed: 05/28/2023]
Abstract
By combining experiments with simple model calculations, we obtain new insight in spin transport through hybrid, CoFeB/Al2O3(1.5 nm)/tris(8-hydroxyquinoline)aluminium (Alq3)/Co spin valves. We have measured the characteristic changes in the I-V behavior as well as the intrinsic loss of magnetoresistance at the onset of multiple-step tunneling. In the regime of multiple-step tunneling, under the condition of low hopping rates, spin precession in the presence of hyperfine coupling is conjectured to be the relevant source of spin relaxation. A quantitative analysis leads to the prediction of a symmetric magnetoresistance around zero magnetic field in addition to the hysteretic magnetoresistance curves, which are indeed observed in our experiments.
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Affiliation(s)
- J J H M Schoonus
- Department of Applied Physics, cNM, Eindhoven University of Technology, The Netherlands
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43
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Koopmans B, Pouwer F, de Bie RA, Leusink GL, Denollet JKL, Pop VJM. Associations between vascular co-morbidities and depression in insulin-naive diabetes patients: the DIAZOB Primary Care Diabetes study. Diabetologia 2009; 52:2056-63. [PMID: 19669635 PMCID: PMC2744805 DOI: 10.1007/s00125-009-1460-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 06/16/2009] [Indexed: 12/02/2022]
Abstract
AIMS/HYPOTHESIS The aim of the study was to determine the prevalence of depression in insulin-naive diabetes patients and to investigate the associations between different forms of vascular co-morbidity and depression. METHODS Cross-sectional data were used from a primary-care sample of 1,269 insulin-naive (i.e. not using insulin therapy) diabetes patients participating in the DIAZOB Primary Care Diabetes study. Demographics, vascular co-morbidities, clinical and lifestyle characteristics, and psychosocial factors were assessed. Depression symptoms were measured with the Edinburgh Depression Scale, with a score >11 defined as depression. The chi (2) and Student's t tests were used to compare groups with and without vascular co-morbidities. Rates and odds ratios of depression were calculated for each vascular co-morbidity, with diabetes only as the reference group, correcting for age and sex. Single and multiple logistic regression analyses were performed to test a more comprehensive model regarding the likelihood of depression in diabetes. RESULTS The prevalence of depression was 11% in the total sample with little difference between the groups with and without any vascular co-morbidity (11.2% vs 10.0%). Single vascular co-morbidities were not associated with increased rates of depression. The final model predicting depression included: having multiple vascular co-morbidities compared with none; having less social support; having experienced a recent stressful life event; female sex; and being a smoker. CONCLUSIONS/INTERPRETATION Rates of depression in those with one additional vascular co-morbidity did not differ from patients with diabetes only. Vascular co-morbidities were only associated with higher depression scores in case of multiple co-morbidities.
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Affiliation(s)
- B. Koopmans
- Center of Research on Psychology in Somatic diseases (CoRPS), Department of Medical Psychology, Tilburg University, P.O. Box 90153, 5000 LE Tilburg, the Netherlands
| | - F. Pouwer
- Center of Research on Psychology in Somatic diseases (CoRPS), Department of Medical Psychology, Tilburg University, P.O. Box 90153, 5000 LE Tilburg, the Netherlands
| | - R. A. de Bie
- CAPHRI School, Department of Epidemiology, Maastricht University, Maastricht, the Netherlands
| | | | - J. K. L. Denollet
- Center of Research on Psychology in Somatic diseases (CoRPS), Department of Medical Psychology, Tilburg University, P.O. Box 90153, 5000 LE Tilburg, the Netherlands
| | - V. J. M. Pop
- Center of Research on Psychology in Somatic diseases (CoRPS), Department of Medical Psychology, Tilburg University, P.O. Box 90153, 5000 LE Tilburg, the Netherlands
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Bloom FL, Kemerink M, Wagemans W, Koopmans B. Sign inversion of magnetoresistance in space-charge limited organic devices. Phys Rev Lett 2009; 103:066601. [PMID: 19792591 DOI: 10.1103/physrevlett.103.066601] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Indexed: 05/28/2023]
Abstract
In this Letter, we explain the puzzling sign change of organic magnetoresistance in space-charge limited devices by device physics. We prove analytically and numerically that in the case of bipolar conduction with an Ohmic majority carrier and an injection limited minority carrier contact, a decrease in minority carrier mobility may give rise to an increase in the device current. It is shown that when the magnetic field acts to decrease the mobility of both carriers, a sign change in the magnetoconductivity as a function of applied bias may result. This behavior is in agreement with experimental observations.
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Affiliation(s)
- F L Bloom
- Department of Applied Physics, Center for NanoMaterials, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.
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Koopmans B, Andersen BL, Mørk NJ, Austad J, Suhonen R, Roders GA. Multicentre randomized double-blind study of Locoid Lipocream fatty cream twice daily versus Locoid Lipocream once daily and Locobase once daily. J DERMATOL TREAT 2009. [DOI: 10.3109/09546639509097161] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Bobbert PA, Wagemans W, van Oost FWA, Koopmans B, Wohlgenannt M. Theory for spin diffusion in disordered organic semiconductors. Phys Rev Lett 2009; 102:156604. [PMID: 19518664 DOI: 10.1103/physrevlett.102.156604] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Indexed: 05/27/2023]
Abstract
We present a theory for spin diffusion in disordered organic semiconductors, based on incoherent hopping of a charge carrier and coherent precession of its spin in an effective magnetic field, composed of the random hyperfine field of hydrogen nuclei and an applied magnetic field. From Monte Carlo simulations and an analysis of the waiting-time distribution of the carrier we predict a surprisingly weak temperature dependence, but a considerable magnetic-field dependence of the spin-diffusion length. We show that both predictions are in agreement with experiments on organic spin valves.
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Affiliation(s)
- P A Bobbert
- Department of Applied Physics, Technische Universiteit Eindhoven, 5600 MB Eindhoven, The Netherlands
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47
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Kurnosikov O, Nietsch JH, Sicot M, Swagten HJM, Koopmans B. Long-range electron interferences at a metal surface induced by buried nanocavities. Phys Rev Lett 2009; 102:066101. [PMID: 19257608 DOI: 10.1103/physrevlett.102.066101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Indexed: 05/27/2023]
Abstract
Apparent c(2x2) superstructures within the narrow beams of an interference pattern spreading in the 100 directions at the surface of Cu(001) are observed by scanning tunneling microscopy. These features are induced by electron scattering from Ar- and Ne-filled subsurface nanocavities. The beams originate from electron anisotropy resulting in focusing of bulk electrons. We developed a model providing a good agreement between simulations and experiments. Particularly, a simple explanation of the angular distribution for the interference pattern and the period in the superstructure is found.
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Affiliation(s)
- O Kurnosikov
- Department of Applied Physics, cNM, Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
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48
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Paluskar PV, Lavrijsen R, Sicot M, Kohlhepp JT, Swagten HJM, Koopmans B. Correlation between magnetism and spin-dependent transport in CoFeB alloys. Phys Rev Lett 2009; 102:016602. [PMID: 19257223 DOI: 10.1103/physrevlett.102.016602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Indexed: 05/27/2023]
Abstract
We report a correlation between the spin polarization of the tunneling electrons and the magnetic moment of amorphous CoFeB alloys. Such a correlation is surprising since the spin polarization of the tunneling electrons involves s-like electrons close to the Fermi level (E_{F}), while the magnetic moment mainly arises due to all the d electrons below E_{F}. We show that probing the s and d bands individually provides clear and crucial evidence for such a correlation to exist through s-d hybridization, and demonstrate the tunability of the electronic and magnetic properties of CoFeB alloys.
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Affiliation(s)
- P V Paluskar
- Department of Applied Physics, cNM, Eindhoven University of Technology, 5600 MB, The Netherlands
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49
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Boulle O, Kimling J, Warnicke P, Kläui M, Rüdiger U, Malinowski G, Swagten HJM, Koopmans B, Ulysse C, Faini G. Nonadiabatic spin transfer torque in high anisotropy magnetic nanowires with narrow domain walls. Phys Rev Lett 2008; 101:216601. [PMID: 19113434 DOI: 10.1103/physrevlett.101.216601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Indexed: 05/27/2023]
Abstract
Current induced domain wall (DW) depinning of a narrow DW in out-of-plane magnetized (Pt/Co)_{3}/Pt multilayer elements is studied by magnetotransport. We find that for conventional measurements Joule heating effects conceal the real spin torque efficiency and so we use a measurement scheme at a constant sample temperature to unambiguously extract the spin torque contribution. From the variation of the depinning magnetic field with the current pulse amplitude we directly deduce the large nonadiabaticity factor in this material and we find that its amplitude is consistent with a momentum transfer mechanism.
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Affiliation(s)
- O Boulle
- Fachbereich Physik, Universität Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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50
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Schoonus JJHM, Bloom FL, Wagemans W, Swagten HJM, Koopmans B. Extremely large magnetoresistance in boron-doped silicon. Phys Rev Lett 2008; 100:127202. [PMID: 18517905 DOI: 10.1103/physrevlett.100.127202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Indexed: 05/26/2023]
Abstract
Boron-doped Si-SiO2-Al structures are fabricated to study extremely large magnetoresistance (MR) effects. Current-voltage characteristics show a nonlinear behavior, dominated by an autocatalytic process of impact ionization. At low temperatures, the magnetic field postpones the onset of impact ionization to higher electric fields. This results in a symmetric positive MR of over 10,000% at 400 kA/m. Applying a magnetic field leads to an increase of the acceptor level compared to the valence band as deduced by admittance spectroscopy. A macroscopic transport model is introduced to describe how the MR is controlled by voltage, electrode spacing, and oxide thickness.
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Affiliation(s)
- J J H M Schoonus
- Department of Applied Physics, cNM, Eindhoven University of Technology, The Netherlands
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