Full Symposium Descriptions

This symposium will explore the latest advancements in forensic chemistry with a focus on microscopy and microanalysis techniques. Experts from academia, industry, and law enforcement will present cutting-edge research and case studies demonstrating the application of these techniques in solving complex forensic problems. Topics will include the application of microanalytical techniques (SEM/EDS, Raman, and FT-IR micro-spectroscopy, and other) and methods in the analysis of trace evidence, materials characterization, foreign/extraneous matter in pharmaceutical manufacturing forensics, and crime scene investigation. Attendees will gain insights into the technological innovations driving the field and the practical challenges faced by forensic chemists.

Organizers:

• Xavier Odihirin, Bristol Myers Squibb
• Ravi Kalyanaraman, Bristol Myers Squibb

4DSTEM has become a crucial tool in microscopy. Presentations are welcomed on all aspects of this burgeoning area including hardware and acquisition developments, acquisition protocols, analysis theory, tools and codes, machine learning applications, computer infrastructure developments for data handling and processing, interpretation of results, and applications in any field of nano-and atomic-scale analysis.

Organizers:

• Ian MacLaren, University of Glasgow
• Colin Ophus, Stanford University
• Stephanie Ribet, Lawrence Berkeley Nation Laboratory

Recent instrumental developments in Atom Probe Tomography (APT) have considerably increased the fields of applications and the data quantity and quality resulting from the analyses. This symposium aims to discuss the latest groundbreaking applications of APT in material sciences, showcasing its versatility across structural, functional, and biological materials. As physical, structural, or chemical information are embedded and often hidden within these massive troves of data, this symposium also covers new data processing techniques and methods enabling better exploration of complex materials systems. Topics of interest include, but are not limited to, data analysis methods, mass spectrometry, image analysis, tomographic reconstruction, and interoperability.

Organizers:

• Eason (Yi-Sheng) Chen, Nanyang Technological University
• Claudia Fleischmann, imec
• Sandra Taylor, Pacific Northwest National Laboratory (PNNL), USA
• Se-Ho Kim, Korea University

Sponsored by the Atom Probe Tomography Focused Interest Group

This symposium will foster exchanges on the latest in using cryogenic electron microscopy (cryo-EM) to study energy and quantum materials. Cryogenic sample preparation and imaging techniques enable analysis of beam-sensitive materials and interfaces in energy materials, and new holders allow for investigation of low temperature quantum phases at the atomic scale.

This symposium will also discuss synergies between cryo-EM and complementary techniques such as atom probe tomography and synchrotron experiments. A major challenge in both quantum and energy materials research is linking macro- and micro-scale properties with atomic-scale characterization. Therefore, we also welcome contributions in theory, data analysis, and AI/ML.

Organizers:

• John Watt, Los Alamos National Laboratory
• Michael Zachman, Oak Ridge National Laboratory
• Shelly Conroy, Imperial College London
• Ismail El Baggari, Harvard University
• Eren Suyolcu, Max Planck

Sponsored by the Low Temperature EM Focused Interest Group

This symposium is a platform to provide an overview of recent developments in focused ion beam (FIB) instrumentation and accessories, as well as a forum for FIB practitioners to share and discuss novel applications and techniques across all scientific disciplines. The emphasis is on innovative approaches to ion imaging, sample preparation, micro/nanofabrication, simulation and modeling, and analytics that go beyond conventional methods in materials and life science research.

Organizers:

• Matthew Thorseth, The Dow Chemical Company
• Valerie Brogden, Covalent Metrology
• Tomoko Borsa, COSINC, University of Colorado Boulder
• Vivek Subramanian, Thermo Fisher Scientific

Sponsored by the Focused Ion Beam Focused Interest Group

Real-world systems are hierarchical, encompassing large differences in size, structure, composition, and arrangement. Correlative microscopy/spectroscopy and analysis have evolved to an indispensable toolkit to characterize these complex systems and have led to advances in both soft and hard material studies by providing information with complimentary modalities and across different scales. In this symposium, we highlight technical innovations in instrument development, sample preparation and handling, in-situ and cryogenic sample environment, and big data (image) analysis pipeline. We also seek contributions on applying correlative, multimodal methods designed for physical, chemical, environmental, materials, biological, and bio-engineering studies.

Organizers:

• Xiao-Ying Yu, Oak Ridge National Laboratory
• Si Chen, Argonne National Laboratory
• Kerim Arat, Quantum Design Inc.
• Raul Arenal, University of Zaragoza

Standard electron microscopy excels at determining the physical structure of a sample. With suitable spectroscopic attachments, it can identify the elements present and even their chemical bonding states. However, standard electron microscopy struggles if tasked with distinguishing a conductor from an insulator, or an active device from a quiescent one. The electronic and thermal structure that is invisible to standard electron microscopy is what fundamentally determines microelectronic device functionality. This symposium will treat recent developments in the effort to map electronic structure and thermal structure at high spatial resolution in modern electronic devices.

Organizers:

• B.C. Regan, UCLA
• William Hubbard, NanoElectronic Imaging, Inc.
• Leopoldo Molina-Luna, TU Darmstadt

Real World Problem solving using all forms of microscopy.

Organizers:

• Abigail Lindstrom, NIST
• Jeremy Beebe, Dow Chemical
• Ke Bin Low, Thermo Fisher Scientific
• Xiofeng Zhang, Xi'an Jiaotong University

We invite contributions developing and applying advanced high-dimensional imaging methods to drive material science. The major focus of this session is on the extra and unique information that becomes available when going beyond standard 2D data acquisition routines which are not available otherwise. The scope of the symposium covers: (1) 2D/3D/4D imaging approaches based on FIB-SEM-, neutron- or synchrotron tomography, m-XCT and X-ray microscopy for ex- and in-situ experiments, TEM-approaches as well as correlative multiscale and multi-method measurement workflows incorporating structural and chemical or mechanical information (2) 3D hyperspectral mapping with a variety of excitation sources (e.g. electrons or X-rays across a variety of scales (e.g. nm to mm) including destructive (e.g. FIB-SEM) and non-destructive methods (e.g. confocal MXRF), (3) predictive and generative AI approaches for image analysis and understanding the structure property relationship. (4) addressing the challenges of high-dimensional image data acquisition, processing, and image quantification. Examples of relevant material classes include, but are not limited to, energy materials, materials for nano-microelectronics, lightweight materials, new structural alloys, polymers, biological materials, and composites.

Organizers:

• Brian Patterson, Los Alamos National Laboratory
• Stephen Kelly, Carl Zeiss X-ray Microscopy
• Roland Brunner, Materials Center Leoben Forschung GmbH (MCL)

This symposium will cover the latest developments in advanced hardware, accessories and software tools for electron microscopy. While primarily focused on aberration corrected instruments, other recent developments in hardware, software and new emergent applications are also encouraged. We welcome topics utilizing AI tools to automate data collection and analysis processes. We particularly encourage the adoption of open-source codes, tools and standards.

Organizers:

• Shize Yang, Yale University
• Andrew Lupini, Oak Ridge National laboratory
• David Bell, Harvard University

Sponsored by the Aberration Corrected Electron Microscopy Focused Interest Group

Our understanding of the 3D structure and functional subtleties of complex biological systems has skyrocketed due to recent advances in EM imaging technology and hybrid methodologies. This symposium will highlight structural studies of macromolecules, microorganisms, cells, and tissues using state-of-the-art high-resolution techniques. These techniques include single particle cryo-EM, cryo-electron tomography, helical reconstruction, STEM; AFM, X-ray crystallography, and molecular modeling. Biological topics of interest include cellular architecture, metabolism, trafficking, communication, and division; gene regulation, transcription, and translation; host-pathogen interactions and virus structure; in situ studies using TEM and SEM, and all aspects of structure-function studies of biological assemblies.

Organizers:

• Claudia Lopez, Oregon Health & Science University
• Ed Eng, New York Structural Biology Center
• Melanie Ohi, University of Michigan
• Teresa Ruiz, University of Vermont

Sponsored by the 3D-EM in Biological Sciences Focused Interest Group

Advances in tissue clearing, expansion microscopy (ExM), and large-scale volumetric imaging are transforming our ability to visualize complex biological structures in unprecedented detail. This symposium will address recent developments in these imaging techniques, focusing on their applications, challenges, and innovations that push the boundaries of biomedical research. Topics will include the evolution of tissue clearing protocols, novel expansion methods for enhanced biomolecule retention, and the integration of high-speed, high-resolution imaging technologies. This forum invites researchers to discuss how these advancements are enabling breakthrough insights in fields such as neuroscience, pathology, and infectious disease research.

Organizers:

• Yongxin Zhao, Carnegie Mellon University
• Alan Watson, University of Pittsburgh
• Adam Glaser, The Allen Institute of Neural Dynamics

Light and electron microscopy are essential tools in the research and diagnosis of diseases in humans, animals, and plants. Progress in sample preparation, image acquisition, and AI-supported image analysis techniques has improved pathogen detection, disease tracking, and the analysis of pathogenic mechanisms. This symposium will investigate the most recent advancements in microscopy for examining disease at the cellular, ultrastructural, and molecular levels. It will also encompass emerging technologies, such as soft x-ray tomography, spatial biology methods, and AI image analysis, which complement and enhance more traditional methodologies..

Organizers:

• Mike Reichelt, Genentech, Inc.
• Claudia Lopez, Oregon Health & Science University

Sponsored by the Diagnostic & Biomedical Microscopy Focused Interest Group

This symposium will cover the following topics:

• Cryo sample preparation, including cryo-FIB
• EM Instrumentation (cameras, phase plates, automation)
• Imaging modes including STEM and 4D-STEM
• Image processing for single-particle and tomographic reconstructions
• Aplications using cutting-edge technology
• Adoption of new technologies

Organizers:

• Claudia Lopez, Oregon Health & Science University
• Ed Eng, New York Structural Biology Center
• Matthew Peet, MRC Laboratory of Molecular Biology
• Yue Yu, Chan Zuckerberg Institute for Advanced Biological Imaging
• Christopher Russo, MRC Laboratory of Molecular Biology

This symposium will cover recent advances in super-resolution light microscopy, covering techniques that deliver unprecedented resolution as well as ones that democratize light microscopy below the diffraction limit. Sessions will highlight advances in instrumentation, sample preparation, imaging workflows, and data analysis and spotlight novel applications made possible by emerging technologies.

Organizers:

• Rengasayee Veeraraghavan, Ohio State University
• Jonathan Boyd, Astra Zeneca
• Louisa Mezache, Aix-Marseille University

This symposium will cover imaging modes including STEM and 4D-STEM.

Organizer:

• Daniel Foley, Johns Hopkins University

Modern research and manufacturing across industries, particularly pharmaceuticals, increasingly demands products with precisely targeted functionalities: enhanced performance, improved sustainability, elevated safety standards, and superior user experience. Success in these endeavors hinges on our ability to understand and control material structures at the microscopic level with unprecedented precision.

Microstructural analysis encompasses three critical dimensions: visualization, identification, and quantification. This symposium presents groundbreaking advances in microscopy and microanalysis techniques, with artificial intelligence serving as the transformative catalyst. Featured innovations include machine learning enhanced microscopy, deep learning powered image analysis, real-time live cell imaging, and AI driven microstructure characterization. All unified by a commitment to quantitative precision.

Revolutionary Impact in Pharmaceutical Development

Within pharmaceutical research, these technologies are fundamentally reshaping drug discovery and development paradigms. AI driven analysis combined with live cell imaging enables unprecedented real time observation and quantification of cellular responses, elucidating drug mechanisms of action while monitoring cellular health dynamics. This technological convergence accelerates the identification of promising therapeutic compounds, streamlines toxicity screening protocols, and supports the formulation of more effective, safer therapies.

Broader Industrial Applications

These cutting-edge methodologies are revolutionizing our capacity to characterize microstructures and their functional properties across multiple domains. Applications span from developing next generation materials with custom engineered properties to optimizing manufacturing processes, ultimately delivering substantial improvements in product quality and reliability. In pharmaceutical contexts, these advances prove particularly crucial for accelerating innovation cycles, enhancing drug efficacy, and ensuring robust patient safety protocols.

The convergence of AI and microanalysis represents more than technological advancement it embodies a paradigm shift toward precision driven industrial innovation, where microscopic insights translate directly into macroscopic breakthroughs across diverse sectors.

Organizers:

• Yan Wang, Kraft Heinz Company
• Jinping Dong, Cargill
• Jonathan Boyd, Astra Zeneca

 Sponsored by the Pharmaceuticals Focused Interest Group

Energy materials are critical for advancing technologies in clean energy, batteries and electronic devices. However, many of these materials, including 2D materials, metal-organic frameworks, and hybrid perovskites, are inherently electron beam-sensitive, posing challenges for effective TEM/STEM characterization. This symposium will examine cutting-edge techniques, including cryo-EM, cryo-ET, and dose-efficient ptychography, aimed at minimizing beam damage while maximizing material insights, at the highest resolutions possible. We aim to foster discussions on the latest advancements in TEM techniques for beam-sensitive materials, promoting knowledge exchange and collaboration in this vital area of research.

Organizers:

• Yi Cui, Stanford University
• Kate Reidy, Stanford University
• Yuzhang Li, University of California, Los Angles
• Yu Han, South China University of Technology

EElectron-based hyperspectral imaging (HSI) offers higher spatial resolution and more diverse material analysis than its photon-based counterpart. In a transmission electron microscope (TEM), HSI enables spectrum-images (SI) using techniques such as electron energy loss spectroscopy (EELS), energy dispersive spectroscopy (EDS), and cathodoluminescence (CL). Therefore, HSI in scanning TEM (STEM) mode provides unique opportunities to connect fundamental and emergent material properties at the nanometer to the atomic scale. As a result, HSI in TEM is a powerful tool for atomic-scale characterization of advanced materials such as metal alloys, 2D materials, semiconductors, and high-entropy materials, which have a high impact on electronics, energy, and metallurgy.

Organizers:

• Dalaver Anjum, Khalifa University
• Manuel Roldan Gutierrez, Arizona State University
• Sriram Vijayan, Michigan Technologiclal University
• Sachan Ritesh, Oklahoma State Umniversity

The overarching goal of this Interdisciplinary/"Cross-cut" symposium for the 2026 M&M Conference is to bring biological and physical/materials science electron microscopists together to strengthen experimental data preservation and validation practices across the sciences. Rapid advances in atomic-level studies of biomolecular structures have been enabled by the Protein Data Bank (PDB) and Electron Microscopy Data Bank (EMDB) open-access data archives. Lessons learned and best practices from biology will be reviewed and opportunities for their adoption within the physics and materials science communities will be explored.

Organizers:

• Stephen Burley, RCSB Protein Data Bank
• Wah Chiu, Stanford University/SLAC

As microscopy advances, the ability to process and analyze data in real time is transforming how we conduct experiments. This symposium invites contributions showcasing innovative software and systems that enhance real-time data processing at the microscope. Whether through improved visualization tools that aid microscopists in making informed decisions or autonomous systems that optimize data acquisition with minimal user input, we aim to explore the cutting-edge technologies driving this field forward.

Organizers:

• Benjamin Miller, Gatan
• Steven Spurgeon, National Renewable Energy Laboratory
• Wei-Chang (David) Yang, National Institute of Standards and Technology
• Mary Scott, University of California, Berkeley

As microscopy and diffraction techniques advance, Electron Backscatter Diffraction (EBSD), Electron Channeling Contrast Imaging (ECCI), and related methods like TKD and STEM-in-SEM are offering transformative insights across various fields. This session will explore innovative applications in both natural and engineered materials, as well as biological systems, focusing on advanced techniques for microstructure quantification and defect analysis. We'll highlight technique developments including in situ methods, machine learning applications, correlative workflows, and new hardware (e.g., pFIB, laserFIB, on/near-axis TKD detectors). With these advances, the goal is to create high-contrast, information-rich maps that provide deeper insights into material behavior.

Organizers:

• Tirzah Abbott, Northwestern University
• Julia Deitz, Sandia National Laboratory
• Stuart Wright, Ametek
• Ben Britton, The University of British Columbia

Molecular materials--including polymers, liquid crystals, molecular assemblies, covalent– and metal–organic frameworks—are foundational to a range of applications, from sensors to membranes, coatings, and solar cells. Innovation in low-dose diffraction and imaging of these soft matter systems is transforming our ability to probe structure-function relationships. These advances enable insights into semi-crystalline, nematic, and amorphous phases, allowing us to link nanoscale order and disorder to unique functional properties (including anisotropic and chiral responses). By focusing on the latest electron microscopy approaches to characterizing order, symmetry, and defects, this session will foster understanding the microstructure-property relationships within these versatile materials.

1. Low-dose imaging techniques for visualizing crystalline and semi-crystalline soft matter and interfaces.

2. Nanobeam diffraction and 4D-STEM for defect and disorder analysis

Symmetry effects in structure-property relationships, focusing on chiral and anisotropic behavior.

3. Integrated modeling and experimental methods that connect structural insights to functional properties, including optical, electronic, and mechanical characteristics.

Organizers:

• Prashant Kumar, Nanyang Technological University Singapore
• Sean Collins, Imperial College London
• Andrew Herzing, NIST

Materials that exhibit long-range orders of charge or spin undergo phase transitions driven by external electric and magnetic fields, making them promising candidates for energy-efficient microelectronic applications. Recent advances in electron microscopy have significantly enhanced our understanding of these phase transitions by probing lattice, charge, and spin configurations, as well as their switching dynamics at the atomic scale. This symposium aims to facilitate the exchange of information and scientific discussion regarding the significant progress, challenges, and future directions in the electron microscopy study of materials undergoing phase transitions. The focus will be on new results in quantitative electric and magnetic field mapping, novel instrumentation and techniques for in situ observations, and other cutting-edge topics related to phase transitions.

Organizers:

• Leopoldo Molina-Luna, TU Darmstadt
• Shiqing Deng, University of Science and Technology Beijing

The semiconductor industry drives many of the critical technological advancements of our time, including recent breakthroughs in artificial intelligence (AI) and electric vehicles (EV). Transmission electron microscopy (TEM) has evolved in parallel, delivering critical insights into the materials and processes behind ever-shrinking semiconductor devices that leverage increasingly complex materials. Advanced TEM techniques—such as 4D-STEM, 3D tomography, DPC, and PED-NBD—are routinely employed to characterize the microstructures influencing performance and yield, while also supporting failure analysis across semiconductor technologies in sensing, power management, computing, memory, and communications. Semiconductor TEM would be nowhere without sample preparation and critical developments in TEM for different technologies warrant innovative sample prep methods. Additionally, TEM workflows are being enhanced through automation and AI-assisted data acquisition to accelerate production and development cycles. This symposium, titled "Advanced Transmission Electron Microscopy (TEM) Analysis for Semiconductors," invites submissions showcasing innovative TEM, and TEM-sample preparation methodologies, and their impact on semiconductor technologies.

Organizers:

• Guoda Lian, Texas Instruments inc
• Brendan Foran, AeroSpace Corporation
• Jinguo Wang, Coherent
• Ling Pan, Intel

Quantum materials, with their exceptional electronic, magnetic, and topological properties, offer transformative potential for next-generation information technologies. 4D-STEM enables simultaneous acquisition of spatial and momentum-resolved information in quantum materials, integrating structural features—such as sub-angstrom lattice details and defects—with charge distribution and electric and magnetic fields to uncover underlying physical phenomena. Complementing this, in situ electron microscopy provides critical real-time visualization of dynamic processes, linking structural evolution to quantum, energy, and optoelectronic properties. This symposium highlights recent advancements challenges, and opportunities in 4D-STEM and in situ techniques, focusing on their applications to static and dynamic studies of quantum materials.

Organizers:

• Shiqing Deng, University of Science and Technology Beijing
• Thang Pham, Virginia Tech
• Zhen Zhen, Chinese Academy of Sciences
• Alexandre Foucher, Oak Ridge National Laboratory

Electron microscopy is widely used to study defects and crystallographic structures (e.g., grains, precipitates) in materials, providing critical insights into material performance. Microstructures can significantly influence material properties under various processing conditions and environmental exposures, including irradiation, temperature, stress, and corrosion. Recent advances in electron microscopy offer insights beyond imaging, including strain analysis, grain orientation, chemical mapping, and in-situ studies—crucial for material development, failure analysis, and nanomaterials characterization. This symposium focuses on novel microstructural characterization techniques that deepen understanding of the links between processing/operation, microstructures, and material properties.

Organizers:

• Yan-Ru Lin, Oak Ridge National Laboratory
• Kinga Unocic, North Carolina State University
• Jane Howe, University of Toronto
• Grace Burke, Idaho National Laboratory

The symposium focuses on the latest technical developments and applications in liquid and gas phase TEM, including instrument innovations, methodology/workflow development and automation, multimodal and multi-stimuli techniques, and advanced data analysis. It aims to highlight how these aspects contribute to a better understanding of functional materials under realistic conditions. Topics include developments in gas/liquid cell hardware; innovative approaches for multiple-stimuli or multi-modal investigations; electron dose management and radiation damage mitigation; integration of emerging (S)TEM techniques, such as fast cameras and 4D-STEM in gas and liquid environments; and machine learning and AI tools for analyzing time-series and hyperspectral datasets or correlating EM data with activity and/or electrochemical measurements.

Organizers:

• Stephen House, Sandia National Laboratories
• Meng Li, Brookhaven National Laboratory
• Dan Zhou, Leibniz Institute for Crystal Growth, Berlin, Germany
• Beata Layna Mehdi, University of Liverpool, United Kingdom

Sponsored by the Electron Microscopy in Liquids and Gases Focused Interest Group

Future energy systems will expose materials to multiple extreme environments, often simultaneously, such as high temperatures, stress/strain, radiation, and corrosion/oxidation. Understanding the mechanisms of materials’ responses to extreme environments requires advanced in-situ/ex-situ characterization/testing, including analyses of separate and combined or synergistic effects. This symposium will bring together experts in radiation effects, corrosion, mechanical behavior, and advanced microscopy, with an emphasis on the application of latest-generation methods of microscopy, microanalysis, and data analytics to tackle problems in materials subjected to extreme environments.

Organizers:

• Timothy Lach, Oak Ridge National Laboratory
• Mukesh Bachhav, Idaho National Laboratory
• Elizabeth Kautz, North Carolina State University
• Daniel Schreiber, Pacific Northwest National Laboratory

Advanced electron microscopy techniques provide powerful insights into the complex structure-property relationships in functional and quantum materials. Leveraging the latest innovations in data acquisition, in-situ holders, high-speed direct electron detectors, and analytical tools, researchers can now probe emergent phenomena such as correlated electronic states, electric or magnetic field distributions at the atomic scale. These measurements are crucial for understanding and manipulating materials properties, especially in materials where quantum effects or phase transitions play a defining role. This symposium includes recent advancements in multi-modal (scanning) transmission electron microscopy ((S)TEM), focusing on methods to reveal atomic-scale electronic structures, phonon, plasmon or magnon interactions at critical interfaces, and emergent behaviors in multiferroic, topological, superconducting and other quantum materials systems.

Organizers:

• Yu-Tsun Shao, University of Southern California
• Eren Suyolcu, Max Planck Institute for Solid State Research
• Sandhya Susarla, Arizona State University
• Demie Kepaptsoglou, University of York / SuperSTEM, United Kingdom

Understanding the effects of structure and composition at nano and atomic length scales, and short timescales, is at the forefront of research offering new fundamental physics and materials science insights for various applications. Recent advances applying spectroscopies in transmission electron microscopy, scanning electron microscopy, and ultrafast microscopy, including the coupling of light in and out of the electron microscope, have accelerated nano-optics research. This symposium will draw together progress in electron energy loss and gain spectroscopies (EELS and EEGS), cathodoluminescence (CL), photo-induced near field electron microscopy (PINEM), and related techniques applied to semiconductors, 2D materials, and plasmonic and nanophotonic structures.

Organizers:

• Steffi Y. Woo, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory
• Luiz H. G. Tizei, Laboratoire de Physique des Solides, CNRS/Université Paris-Saclay, Orsay, France
• Sean M. Collins, Imperial College London, United Kingdom
• Armin Feist, Max Planck Institute for Multidisciplinary Sciences, University of Göttingen, Göttingen, Germany

This symposium will explore recent advances in microanalytical techniques including but not limited to EDS, WDS, uXRF, LA-ICP-MS, Raman, and ion microprobe as applied to problems of the earth and beyond. While many of these techniques are proven and mature, novel sample preparation, more efficient hardware, larger detector selection, new calibration techniques, spectral analysis, software algorithms, and visualization of data have lowered detection limits and improved accuracy and precision. We invite contributions that highlight new developments in quantitative analysis as applied to terrestrial and planetary samples.

Organizers:

• Heather Lowers, United States Geological Survey
• Jay Thompson, United States Geological Survey
• John Konopka, Retired
• Stephen Seddio, Thermo Fisher