Astrocytes are critically important for neuronal circuit assembly and function. Mammalian protoplasmic astrocytes develop a dense ramified meshwork of cellular processes to form intimate contacts ...with neuronal cell bodies, neurites, and synapses. This close neuron-glia morphological relationship is essential for astrocyte function, but it remains unclear how astrocytes establish their intricate morphology, organize spatial domains, and associate with neurons and synapses in vivo. Here we characterize a Drosophila glial subtype that shows striking morphological and functional similarities to mammalian astrocytes. We demonstrate that the Fibroblast growth factor (FGF) receptor Heartless autonomously controls astrocyte membrane growth, and the FGFs Pyramus and Thisbe direct astrocyte processes to ramify specifically in CNS synaptic regions. We further show that the shape and size of individual astrocytes are dynamically sculpted through inhibitory or competitive astrocyte-astrocyte interactions and Heartless FGF signaling. Our data identify FGF signaling through Heartless as a key regulator of astrocyte morphological elaboration in vivo.
•Flies have a subtype of glia that is similar to mammalian protoplasmic astrocytes•Fly astrocytes are essential for survival and normal nervous system function•Heartless FGF signaling is required for astrocyte morphogenesis
Stork et al. characterize Drosophila astrocytes, demonstrate important roles for these cells in animal behavior and survival, and show that FGF signaling and cell-cell competitive interactions shape astrocyte morphology. Astrocytes therefore fulfill essential functions even in very simple nervous systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Various composite materials used as biomaterials were tested by 20-, 50-, and 80-N chewing forces in distilled water and a poppy seed medium by using a computer-controlled chewing simulation ...procedure. In each chewing test, steatite balls 6 mm in diameter were used as an antagonist material. The mean volume loss of worn surfaces and the surface roughness of the composite materials was measured with a contactless 3D profilometer.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The purpose of the present study was to investigate two and three-body wear resistance and hardness of eighth kinds of modern bulk-fill and resin-based composite materials — Grandio, Estelite Flow, ...Filtek bulk-fill, Charisma, Clearfil, Ultimate, Quadrant, and G-aenial. All samples were kept in distilled water for one week, and their Vickers hardness was determined before two- and three-body wear tests. The mean volume loss of all specimens after the wear tests was determined by the 3D profilometry. In addition, a random specimen was selected from each test group and scanning electron microscope images were taken for an analysis of wear tracks. The surface morphology of the Clearfil and Ultimate composite materials was damaged severely, whereas Grandio and Charisma had a very smooth surface after two-body wear tests. The lowest mean volume loss was measured in micro-fill Grandio two-body and three-body wear tests. The Filtek bulk-fill and resinbased composites showed similar two- and three-body wear behavior. For the composite materials considered, correlations between the filler volume loss, Vickers hardness, and two- and three-body wear resistances were found to be insignificant.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Precise neural circuit assembly is achieved by initial overproduction of neurons and synapses, followed by refinement through elimination of exuberant neurons and synapses. Glial cells are the ...primary cells responsible for clearing neuronal debris, but the cellular and molecular basis of glial pruning is poorly defined. Here we show that Drosophila larval astrocytes transform into phagocytes through activation of a cell-autonomous, steroid-dependent program at the initiation of metamorphosis and are the primary phagocytic cell type in the pupal neuropil. We examined the developmental elimination of two neuron populations-mushroom body (MB) γ neurons and vCrz⁺ neurons (expressing Corazonin Crz neuropeptide in the ventral nerve cord VNC)-where only neurites are pruned or entire cells are eliminated, respectively. We found that MB γ axons are engulfed by astrocytes using the Draper and Crk/Mbc/dCed-12 signaling pathways in a partially redundant manner. In contrast, while elimination of vCrz⁺ cell bodies requires Draper, elimination of vCrz⁺ neurites is mediated by Crk/Mbc/dCed-12 but not Draper. Intriguingly, we also found that elimination of Draper delayed vCrz⁺ neurite degeneration, suggesting that glia promote neurite destruction through engulfment signaling. This study identifies a novel role for astrocytes in the clearance of synaptic and neuronal debris and for Crk/Mbc/dCed-12 as a new glial pathway mediating pruning and reveals, unexpectedly, that the engulfment signaling pathways engaged by glia depend on whether neuronal debris was generated through cell death or local pruning.
Highlights • A decision support system for classification of dental lesions on CBCT is proposed. • The database used in this study is consisted of 50 different dental CBCT scans. • Dental periapical ...cyst and keratocystic odontogenic tumor lesions were classified. • Six different classifiers were used for the classification experiments. • The Support Vector Machine (SVM) achieved the best classification performances.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Background
Many children with hematologic and oncologic diagnoses require opioids for management of pain, yet knowledge gaps persist among pediatric hematology/oncology (PHO) fellows.
Objective
...Pediatric Opioid Analgesia Self‐Instruction System (PedOASIS) is an interactive, case‐based education tool designed for independent learning. The goal of this study was to evaluate its efficacy in increasing PHO fellows’ knowledge and comfort with using opioids to manage pain.
Design/method
PHO fellows were recruited from 74 American College of Graduate Medical Education‐accredited US programs during the 2019–2020 academic year and randomized to receive access to PedOASIS (intervention) or usual PHO training (control). Surveys at baseline, immediately after accessing the tool, and 6 months later assessed knowledge and comfort related to prescribing opioids.
Results
A total of 64 PHO fellows completed the study, with 32 in the intervention group and 32 controls. At baseline, mean scores on the 10‐question knowledge assessment were similar between groups (intervention: 5, control: 6; p = .8). Following intervention, mean score was significantly higher in the intervention group (9) versus controls (5; p < .0001). Six months later, scores in both groups decreased but remained significantly higher in the intervention group (7) compared to controls (5, p < .0001) and compared to baseline (p = .0002). Fellows in the intervention group reported significant increases in comfort dosing opioids after exposure to the tool (p = .02).
Conclusion
PHO fellows exposed to the tool had improved scores on validated knowledge questions and greater comfort using opioids for pain management compared to controls. We therefore suggest that PedOASIS warrants further evaluation as a potential tool for PHO fellows.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Developing strategies for atomic-scale controlled synthesis of new two-dimensional (2D) functional materials will directly impact their applications. Here, using in situ aberration-corrected scanning ...transmission electron microscopy, we obtain direct insight into the homoepitaxial Frank-van der Merwe atomic layer growth mechanism of TiC single adlayers synthesized on surfaces of Ti
C
MXene substrates with the substrate being the source material. Activated by thermal exposure and electron-beam irradiation, hexagonal TiC single adlayers form on defunctionalized surfaces of Ti
C
MXene at temperatures above 500 °C, generating new 2D materials Ti
C
and Ti
C
. The growth mechanism for a single TiC adlayer and the energies that govern atom migration and diffusion are elucidated by comprehensive density functional theory and force-bias Monte Carlo/molecular dynamics simulations. This work could lead to the development of bottom-up synthesis methods using substrates terminated with similar hexagonal-metal surfaces, for controllable synthesis of larger-scale and higher quality single-layer transition metal carbides.
The aim of this study was to investigate the three‐body wear resistance and hardness of commercially pure titanium and titanium alloys containing zirconium and tantalum (cp‐Ti, Ti‐5Zr and Ti‐5Ta). ...Each titanium test group, were subjected to wear tests under 105 wear cycles, 50 N mechanical force, 2.0 Hz wear frequency, 6 mm diameter Al2O3 antagonist ball, 5 °C/55 °C thermal change conditions immersed in poppy seed slurry as third‐body medium. The mean wear volume loss and depth of all test specimens after the three‐body wear tests was determined with use non‐contact 3D profilometer and also Vicker's hardness was measured. Wear area of microstructures were evaluated using scanning electron microscopy (SEM) and x‐ray diffraction (XRD) analysis. The hardness of Ti‐5Zr material was significantly greater than the other alloy material and cp‐Ti. However, for the test materials in this study considered, correlations between the three‐body wear resistance and hardness were found to be insignificant. It was concluded, the three‐body wear resistance of the alloy formed with the adding of zirconium and tantalum to the pure titanium is increased after wear tests.
The wear of teeth and dental materials in the oral tribological process can be defined as the net volume loss of the material. It is possible to say that four basic wear mechanisms occur during human chewing movement. These wear mechanisms are called attrition (two‐body), abrasion (three‐body), fatigue and corrosive wear mechanism.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Image segmentation, is of utmost importance in the disciplines of digital image processing, particularly remote sensing and computer vision, has seen an increasing demand for precise and efficient ...algorithms. This study focuses to conduct a comparative exploration of the segmentation capabilities of two sophisticated techniques namely, Multiresolution Segmentation (MRS) and Segment Anything Model (SAM), leveraging the high-resolution WorldView-3 (WV-3) satellite image. MRS adopts a hierarchical methodology, segmenting an image into various scales while retaining a profound understanding of its structure. Conversely, SAM employs a deep learning algorithm, prioritizing segment creation based on conceptual pixel similarity, irrespective of spatial adjacency. The WV-3 image, featuring diverse land cover elements like agricultural parcels, industrial structures, roads, red roofs, single trees, and water bodies, serves as the basis for assessing segmentation quality. Both methods are applied to the image, and their outcomes are individually evaluated against manually generated polygonal land use/cover objects. Segmentation quality metrics are employed for assessment. Results reveal MRS effectively preserves fine details and entity delineation, while SAM excels in capturing contextually similar regions. MRS outperforms SAM with a negligible discrepancy, yet SAM demonstrates superiority in the red roof object, achieving an Intersection over Union (IoU) value of 0.70 compared to MRS’s 0.49. MRS tends to generate numerous segments for an item, while SAM produces only one segment. Nevertheless, it is important to recognise that both algorithms have specific constraints in particular scenarios, such as excessive segmentation in areas with abundant texture or inadequate segmentation in areas with slight changes.
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