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Despite increasing concern about the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species, such as the Little Penguin (Eudyptula minor). In this study, we collected freshly deceased Little Penguins for dissection and micro-computed tomography (microCT) scans. The head structures, including the ear apparatus, were reconstructed based on high-resolution imaging data for the species. Moreover, three-dimensional finite-element models were built based on microCT data to simulate the sound reception processes and ear responses to the incident planar waves at the selected frequencies. The received sound pressure fields and motion (i.e. displacement and velocity) of the internal ear-related structures were modelled. The synergistic response of ear components to incident aerial and underwater sounds was computed to predict the hearing capabilities of the Little Penguins across a broad frequency range (100 Hz–10 kHz), both in air and under water. Our predicted data showed good agreement with other diving birds in both the form and range of auditory sensitivity. This study demonstrates a promising method to study hearing in other inaccessible animals. The outputs from this study can inform noise impact mitigation and conservation management.

Simple Summary: The foregut of the glassy-winged sharpshooter is difficult to dissect and observe in three dimensions with SEM or TEM. We describe an X-ray micro-computed tomography (microCT)-based method for studying the GWSS foregut including the precibarium and the cibarium, with high resolution. MicroCT imaging showed great promise for the study of the tissues and structures of small insects. Dissecting the heads of small insects belonging to the order Hemiptera for detailed anatomical investigation with light or scanning electron microscopy is difficult, time-consuming, and destructive, often resulting in sample preparation artifacts. Nevertheless, the structural details of these insects often hold critical information regarding their interactions with bacterial pathogens. For example, the glassy-winged sharpshooter (GWSS) is an efficient vector of the bacterium Xylella fastidiosa, the causal agent of Pierce's disease in grape vines, but the foregut of this species is exceptionally difficult to dissect. Here, we describe a simple, non-destructive method to investigate the structure of the anterior gut of GWSS using high-resolution micro-computed X-ray tomography (microCT). The use of microCT eliminates the need for destructive dissection and reveals the morphology of small insects in three dimensions, allowing the user to virtually dissect the sample. The use of microCT imaging is a promising and powerful tool in the entomological sciences for studying the structures of vector insects, especially for difficult-to-dissect regions such as the foregut. [ABSTRACT FROM AUTHOR]

Bony labyrinth morphology varies across marine mammals and contains key information regarding hearing sensitivity and ecology. The hearing ranges of globicephaline (Delphinidae: Globicephalinae) or melon‐headed dolphins, known as "Blackfish," have been extensively studied using acoustic technologies, but clade‐wide morphological analysis of the bony labyrinth is lacking. In this study, we investigate the variation in hearing‐relevant bony labyrinth morphology within globicephalines using μCT scans of isolated petrosals and digitally isolating the bony labyrinth of all species. Principal components analysis (PCA) of nine hearing‐relevant measurements of the cochlea alongside a broader sampling of terrestrial and aquatic artiodactyls shows Orcaella brevirostris and other globicephalines with higher levels of facial asymmetry and potentially more specialized echolocation abilities plotting near Monodon monoceros, Delphinapterus leucas, and Orcinus orca. The remaining globicephalines, which have more symmetrical skulls and other unique and acoustically relevant attributes, plotted towards the middle of the echolocating odontocete portion of the PCA. Our analysis thus reveals that inner ear morphology may correlate with both facial skull morphology and echolocation specializations, as these are intertwined. Furthermore, this study illustrates how morphological analyses, especially those centered on hearing, may provide critical conservation‐relevant information as direct access to audiograms becomes less tenable. [ABSTRACT FROM AUTHOR]

Despite increasing concern about the effects of anthropogenic noise on marine fauna, relevant research is limited, particularly in those inaccessible species, such as the Little Penguin ( Eudyptula minor ). In this study, we collected freshly deceased Little Penguins for dissection and micro-computed tomography (microCT) scans. The head structures, including the ear apparatus, were reconstructed based on high-resolution imaging data for the species. Moreover, three-dimensional finite-element models were built based on microCT data to simulate the sound reception processes and ear responses to the incident planar waves at the selected frequencies. The received sound pressure fields and motion (i.e. displacement and velocity) of the internal ear-related structures were modelled. The synergistic response of ear components to incident aerial and underwater sounds was computed to predict the hearing capabilities of the Little Penguins across a broad frequency range (100 Hz-10 kHz), both in air and under water. Our predicted data showed good agreement with other diving birds in both the form and range of auditory sensitivity. This study demonstrates a promising method to study hearing in other inaccessible animals. The outputs from this study can inform noise impact mitigation and conservation management., Competing Interests: We declare we have no competing interests., (© 2024 The Author(s).)

Researchers often use skulls prepared by different techniques in geometric morphometrics (GM). The main goal of this paper was to compare and measure errors in GM analyses using snake skulls prepared with two of these techniques (microCT Scan and chemical maceration). We evaluate if analyses employing skulls with both types of preparation may generate biased results or if this parameter is negligible. Thirty‐four heads of Liophis miliaris merremi were first scanned and subsequently prepared following the techniques of chemical maceration. We used 37 and 18 landmarks for dorsal and ventral views of skulls respectively. To evaluate shape differences between the same skull assessed by microCT Scan and chemical maceration, we performed discriminant analyses, Hotelling's T2 and cross‐validation tests. Discriminant analyses showed significant differences between preparation techniques for both views. However, all the differences between dried and microCT scanned skulls were smaller than those between individuals of the same taxon, which means that such differences are within the range of intraspecific variation. The results support the use of specimens prepared according to both techniques in studies of GM. [ABSTRACT FROM AUTHOR]

Biporous media having clusters of size range 300 - 425 μm, 425 - 600 μm, > 600 μm have been sintered at 950 °C, 180 min using gas atomized spherical particles (D50 of 90 microns) of pure copper in reducing atmosphere of pure hydrogen gas. MicroCT scan of biporous samples have been performed to and then images have been reconstructed to 3D CAD models, which further have been discretised into tetrahedral mesh using image processing and reconstruction software Avizo Fire 8.0. Direct numerical simulations have been performed to obtain Evaporative heat transfer coefficient (EHTC) over the surface of these biporous clusters. The transient evaporation phenomena and effect of cluster size on evaporation has been investigated in this paper. These results have been compared with the experimental results available in literature for evaporative heat transfer coefficient for biporous media. [ABSTRACT FROM AUTHOR]

Background: The 3Rs guideline is the gold standard for ethics in animal experimentation. Two of those rules, namely refinement and reduction, require further improvement. The objective of this study was to define pathways to better compliance with these prerequisites. Two methods which move us in this direction are: (1) using small animal imaging techniques for pancreatic ductal adenocarcinoma (PDAC) follow-up and (2) reduction of the number of control animals included in a study of PDAC progression under treatment. Materials and methods: Firstly, we used MicroCT scan to diagnose events showing PDAC progression prior to any clinical symptoms to thereby define more humane endpoints identifiable before any painful phenomenon is observed. Secondly, in order to test the hypothesis of using a reference control group in all preclinical studies of a new treatment of PDAC, we investigated the stability of the results obtained with the control groups in three successive identical studies comparing placebo and gemcitabine in tumor-bearing Lewis rats. Results: Two imaging endpoints were found. The first was the observation of a liver metastasis assessing PDAC diffusion and, earlier than liver metastasis, the presence of bands of fluid along the flanks, with more or less a medial displacement of bowel and solid viscera, reflecting a peritoneal ascites. Results of the longitudinal follow-up of rats in the gemcitabine study revealed heterogeneity in the survival rate in the three control groups, as opposed to the survival rate in the three treated groups which did not differ statistically. As a result, the significance of improved survival with chemotherapy varied greatly according to the control group used for the comparison, ranging from no impact to a highly significant effect. Conclusion: The early detection by the means of animal imaging of one or more signs indicating the onset of a critical step in the development of the disease (e.g., ascites or/and metastasis) allows the researcher to prevent the occurrence of animal pain, thereby ensuring better animal welfare. However, using a single standard control group in an effort to use fewer animals for a given model runs such a significant risk of false results that it mars the entire study. Although reducing the number of animals in a study remains the gold standard of our experimental practice, in this case it would come at the price of a loss of validity of the results. [ABSTRACT FROM AUTHOR]

Conventional methods for extracting fossilised bones from calcified clastic sediments, using air drills or chemical preparations, can damage specimens to the point of rendering them unidentifiable. As an alternative, we tested an in silico approach that extended preparation and identification possibilities beyond those realisable using physical methods, ultimately proving to be crucial in identifying a fragile fossil. Image data from a matrix-encased hemi-mandible of a micromammal that was collected from the Plio-Pleistocene site of Malapa, Cradle of Humankind, South Africa, were acquired using microtomography. From the resultant images, a 3D rendering of the fossil was digitally segmented. Diagnostic morphologies were evaluated on the rendering for comparison with extant comparative specimens, positively identifying the specimen as an elephant shrew (Elephantulus sp.). This specimen is the first positively identified micromammal in the Malapa faunal assemblage. Cutting-edge in silico preparation technology provides a novel tool for identifying fossils without endangering bone integrity, as is commonly risked with physical preparation.

The Miocene fiddler crab Uca maracoani antiqua Brito, 1972, from the Pirabas Formation (Brazil), has been recurrently claimed to be a valid species and the oldest fossil record of the brachyuran crab family Ocypodidae. However, morphological investigations with the aid of microCT scan images of a large number of topotypic specimens and re-examination of the type material of U. maracoani antiqua revealed that it should actually be merged into the synonymy of Uca (Acanthoplax) maracoani (Latreille, 1802). Therefore, U. maracoani , the morphology and ecological traits of which have persisted essentially unchanged for at least 16 Ma (Burdigalian to present), is actually a long-lived crab species inhabiting an estuarine, sheltered mudflat environment that, likewise, has essentially remained unchanged. Burgeoning evidence suggests that evolutionary stasis may not be uncommon among mangrove crabs, as revealed by Afruca tangeri (Eydoux, 1835) from the middle Miocene in northeastern Spain and U. ornata (Smith, 1870) from the Plio-Pleistocene in Honduras. Uca antiqua is redescribed and illustrated based on 3D volume reconstruction and several topotypic specimens. The microCT analysis revealed a considerable number of fossil concretions of U. maracoani , with both males and females likely sharing the same burrow. This is the first fossil record of a male fiddler crab with a female inside a burrow, where mating usually takes place. This mating style is common to almost all extant American fiddler crabs. • This is the first complete and detailed taxonomic review of Uca maracoani antiqua. • Uca maracoani morphology persisted unchanged for at least 16 Ma. • Evolutionary stasis may be not uncommon among fiddler crabs. [ABSTRACT FROM AUTHOR]