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1. Teaching Parasitology Lab Remotely Using Livestreaming

   https://doi.org/10.1525/abt.2022.84.5.312  

   Hawdon, John M.; Bernot, James P. (May 2022, The American Biology Teacher)

   Teaching biology laboratories remotely presents unique problems and challenges for instructors. Microscopic examination of specimens, as is common in parasitology labs, is especially difficult given the limited quantity of teaching specimens and the need for each student to have access to a microscope at their remote location. Observing images of parasites on the internet coupled with written exercises, while useful, is unrepresentative of real-world laboratory or field conditions. To provide a more realistic microscopy-centered synchronous experience for our parasitology class during the coronavirus pandemic, we used a smartphone mounted on a student microscope to livestream examination of parasite specimens to remote students via the Webex meeting app. This allowed two instructors, working from separate locations, to present and narrate the view of the specimens through the microscope in real time to the remotely located class. While less than ideal, livestreaming microscopic views of parasite specimens together with simultaneous instructor narration provided a reasonable remote substitute for a hands-on parasitology lab experience. 

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2. Evolution of texture and internal stresses within polycrystalline rock salt using in situ 3D synchrotron computed tomography and 3D X-ray diffraction

   https://doi.org/10.1107/S1600576721007809  

   Moslehy, Amirsalar; Alshibli, Khalid A.; Truster, Timothy J.; Kenesei, Peter; Imseeh, Wadi H.; Jarrar, Zaher; Sharma, Hemant (October 2021, Journal of Applied Crystallography)

   Rock salt caverns have been extensively used as reliable repositories for hazardous waste such as nuclear waste, oil or compressed gases. Undisturbed rock salt deposits in nature are usually impermeable and have very low porosity. However, rock salt formations under excavation stresses can develop crack networks, which increase their porosities; and in the case of a connected crack network within the media, rock salt may become permeable. Although the relationship between the permeability of rock salt and the applied stresses has been reported in the literature, a microscopic study that investigates the properties influencing this relationship, such as the evolution of texture and internal stresses, has yet to be conducted. This study employs in situ 3D synchrotron micro-computed tomography and 3D X-ray diffraction (3DXRD) on two small-scale polycrystalline rock salt specimens to investigate the evolution of the texture and internal stresses within the specimens. The 3DXRD technique measures the 3D crystal structure and lattice strains within rock salt grains. The specimens were prepared under 1D compression conditions and have shown an initial {111} preferred texture, a dominant {110}〈1 1 0〉 slip system and no fully connected crack network. The {111} preferred texture under the unconfined compression experiment became stronger, while the {111}〈1 1 0〉 slip system became more prominent. The specimens did not have a fully connected crack network until applied axial stresses reached about 30 MPa, at a point where the impermeability of the material becomes compromised due to the development of multiple major cracks. 

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3. Experimental Evaluation of Microvoid Characteristics and Relationship with Stress and Strain for Ductile Fracture

   https://doi.org/10.1061/JMCEE7.MTENG-16698  

   Dey, Surajit; Kiran, Ravi; Ulven, Chad (November 2023, Journal of Materials in Civil Engineering)

   The present study aims to characterize the microvoid sizes and their statistical distribution at the instance of fracture from the fracture surface of steel specimens. To this end, uniaxial tensile tests are conducted on circumferentially notched specimens made of 17-4 PH stainless steel and ASTM A992 high-strength structural steel. The fracture surfaces of the steel test specimens are studied using a digital microscope to quantify the statistical microvoid size distribution. Furthermore, the evaluated microvoid sizes of different fracture locations are mapped with the stress and strain fields. Finally, based on the experimentally evaluated microvoid sizes, an uncoupled fracture model was adopted to predict the fracture displacement and location of ductile fracture initiation in the fractured specimens. The fracture displacements predicted using the calibrated uncoupled fracture model are within the acceptable limit. The fracture initiation locations coincided with the peak strain-averaged stress triaxiality in the fracture specimens. 

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4. The semi-automated development of plant cell wall finite element models

   https://doi.org/10.1186/s13007-023-00979-2  

   Sayad, Andrew; Oduntan, Yusuf; Bokros, Norbert; DeBolt, Seth; Benzecry, Alice; Robertson, Daniel J.; Stubbs, Christopher J. (January 2023, Plant Methods)

   Abstract This study presents a methodology for a high-throughput digitization and quantification process of plant cell walls characterization, including the automated development of two-dimensional finite element models. Custom algorithms based on machine learning can also analyze the cellular microstructure for phenotypes such as cell size, cell wall curvature, and cell wall orientation. To demonstrate the utility of these models, a series of compound microscope images of both herbaceous and woody representatives were observed and processed. In addition, parametric analyses were performed on the resulting finite element models. Sensitivity analyses of the structural stiffness of the resulting tissue based on the cell wall elastic modulus and the cell wall thickness; demonstrated that the cell wall thickness has a three-fold larger impact of tissue stiffness than cell wall elastic modulus. 

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5. Deep learning extended depth-of-field microscope for fast and slide-free histology

   https://doi.org/10.1073/pnas.2013571117  

   Jin, Lingbo; Tang, Yubo; Wu, Yicheng; Coole, Jackson B.; Tan, Melody T.; Zhao, Xuan; Badaoui, Hawraa; Robinson, Jacob T.; Williams, Michelle D.; Gillenwater, Ann M.; et al (December 2020, Proceedings of the National Academy of Sciences)

   null (Ed.)

   Microscopic evaluation of resected tissue plays a central role in the surgical management of cancer. Because optical microscopes have a limited depth-of-field (DOF), resected tissue is either frozen or preserved with chemical fixatives, sliced into thin sections placed on microscope slides, stained, and imaged to determine whether surgical margins are free of tumor cells—a costly and time- and labor-intensive procedure. Here, we introduce a deep-learning extended DOF (DeepDOF) microscope to quickly image large areas of freshly resected tissue to provide histologic-quality images of surgical margins without physical sectioning. The DeepDOF microscope consists of a conventional fluorescence microscope with the simple addition of an inexpensive (less than $10) phase mask inserted in the pupil plane to encode the light field and enhance the depth-invariance of the point-spread function. When used with a jointly optimized image-reconstruction algorithm, diffraction-limited optical performance to resolve subcellular features can be maintained while significantly extending the DOF (200 µm). Data from resected oral surgical specimens show that the DeepDOF microscope can consistently visualize nuclear morphology and other important diagnostic features across highly irregular resected tissue surfaces without serial refocusing. With the capability to quickly scan intact samples with subcellular detail, the DeepDOF microscope can improve tissue sampling during intraoperative tumor-margin assessment, while offering an affordable tool to provide histological information from resected tissue specimens in resource-limited settings. 

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