High-resolution Microtomography Research Articles

Hard X-ray imaging and tomography at the Biomedical Imaging and Therapy beamlines of Canadian Light Source.

The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X-ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high-resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X-ray imaging techniques available to users.

Trade-off between Pore-Throat Structure and Mineral Composition in Modulating the Stability of Soil Organic Carbon.

The preservation of soil organic carbon (OC) is an effective way to decelerate the emission of CO2 emission. However, the coregulation of pore structure and mineral composition in OC stabilization remains elusive. We employed the in situ nondestructive oxidation of OC by low-temperature ashing (LTA) combined with near edge X-ray absorption fine structure (NEXAFS), high-resolution microtomography (μ-CT), field emission electron probe microanalysis (FE-EPMA) with C-free embedding, and novel Cosine similarity measurement to investigate the C retention in different aggregate fractions of contrasting soils. Pore structure and minerals contributed equally (ca. 50%) to OC accumulation in macroaggregates, while chemical protection played a leading role in C retention with 53.4%-59.2% of residual C associated with minerals in microaggregates. Phyllosilicates were discovered to be more prominent than Fe (hydr)oxides in C stabilization. The proportion of phyllosilicates-associated C (52.0%-61.9%) was higher than that bound with Fe (hydr)oxides (45.6%-55.3%) in all aggregate fractions tested. This study disentangled quantitatively for the first time a trade-off between physical and chemical protection of OC varying with aggregate size and the different contributions of minerals to OC preservation. Incorporating pore structure and mineral composition into C modeling would optimize the C models and improve the soil C content prediction.

In vitro assessment of dental erosion caused by clear aligners

The primary objective of this in vitro study was to investigate the erosive potential of enamel under the use of clear aligners (CA), by simulating in vivo conditions experienced by patients who do not remove their CA during the consumption of acidic beverages. In addition, the difference in erosion protection conferred by artificial and human saliva was also evaluated. Sound-extracted human premolars (n = 20) had half of their surfaces protected with acid-resistant nail polish and were randomly distributed into two experimental groups (n = 10): teeth immersed in human saliva or artificial saliva. All teeth had half of their lingual surfaces enclosed by a CA device. The erosive challenges consisted of individual immersion of each sample in citrus acid three times a day, intermediated by immersion in human saliva or artificial saliva for 2 h, during ten days of the erosive protocol. The enamel mineral content was analyzed by high-resolution microtomography. The differential mineral concentration profiles were obtained by subtracting the profile of the mineral concentration of the exposed area and enamel under the CA area from the respective sound area (control). In addition, enamel wear and enamel volume loss were measured. Scanning electron microscopy (SEM) was also performed to analyze the enamel surface. Data were analyzed by two-way ANOVA, followed by the Student-Newman-Keuls test. The enamel wear was higher in teeth immersed in artificial saliva, when compared to human saliva (p < 0.001). The volume loss of the exposed enamel area was lower for tooth immersed in human saliva than in artificial saliva (p < 0.001), during the acid challenge protocol. The use of CA during acid challenges promoted wear and mineral loss of dental enamel, being these changes more pronounced on the enamel surface under the CA. These results open a new path for the development of further studies adopting clinical protocols that promote more accurate responses in the clinical practice during orthodontic treatment.

Estimation of Capillary‐Associated NAPL‐Water Interfacial Areas for Unconsolidated Porous Media by Kinetic Interface Sensitive (KIS) Tracer Method

AbstractBy employing kinetic interface sensitive (KIS) tracers, we investigate three different types of glass‐bead materials and three natural porous media systems to quantitatively characterize the influence of the porous‐medium grain‐, pore‐size and texture on the specific capillary‐associated interfacial area (FIFA) between an organic liquid and water. By interpreting the breakthrough curves (BTCs) of the reaction product of the KIS tracer hydrolysis, we obtain a relation for the specific IFA and wetting phase saturation. The immiscible displacement process coupled with the reactive tracer transport across the fluid–fluid interface is simulated with a Darcy‐scale numerical model. Linear relations between the specific capillary‐associated FIFA and the inverse mean grain diameter can be established for measurements with glass beads and natural soils. We find that the grain size has minimal effect on the capillary‐associated FIFA for unconsolidated porous media formed by glass beads. Conversely, for unconsolidated porous media formed by natural soils, the capillary‐associated FIFA linearly increases with the inverse mean grain diameter, and it is much larger than that from glass beads. This indicates that the surface roughness and the irregular shape of the grains can cause the capillary‐associated FIFA to increase. The results are also compared with the data collected from literature, measured with high resolution microtomography and partitioning tracer methods. Our study considerably expands the applicability range of the KIS tracers and enhances the confidence in the robustness of the method.

Fractal analysis of the mandible cortical bone: correlation among fractal dimension values obtained by two processing methods from periapical radiograph and micro-computed tomography with cone-beam computed tomography.

The objectives of the present study were to assess Fractal Dimension (FD) values in the mandible cortical bone obtained from digital periapical radiographs (DPR), high-resolution microtomography (µCT), and cone-beam computed tomography (CBCT), by two processing methods: binarization (FD.b) and grayscale-based method (FD.f) and, finally, to identify the correlation among these values with other micro-architectural parameters. For this, a prospective study was conducted on 18 healthy individuals (mean age 23 ± 2.4years old) who underwent third molar extraction. Pre-operative CBCT scans were conducted, bone fragments were removed from the retro-molar region, and DPR and µCT were performed on those bone samples. FD.b and FD.f values were calculated using three parasagittal sections for CBCT, one image for DPR, and three sections for µCT. The 3D bone microarchitecture was analyzed in µCT (voxel size: 19µm). As a result, FD.b mean values of 1.55 ± 0.02 and 1.80 ± 0.01 were obtained for CBCT and µCT, respectively. Furthermore, FD.f mean values of 1.22 ± 0.12 for DPR, 0.99 ± 0.04 for CBCT, and 1.30 ± 0.07 for µCT were obtained. Both FD.b and FD.f values showed a good agreement. FD.f was negatively correlated with the standard deviation of the mean gray value (p = 0.003) for DPR and intra-cortical bone surface (p = 0.02) for µCT. In conclusion, image processing with or without binarization revealed different values for FD, although showing agreement. The grayscale-based method retrieved FD values correlated with the gray levels and the cortical porous network, which means that FD can be a valuable index for mandibular cortical bone evaluation. FD is associated with mineralization and microarchitecture. Nevertheless, there was no correlation between FD values obtained from low- (DPR) and high-resolution (µCT) X-ray modalities with FD obtained from the in vivo CBCT.

Deep Paleoproteotyping and Microtomography Revealed No Heart Defect nor Traces of Embalming in the Cardiac Relics of Blessed Pauline Jaricot.

Scientific examination of the heart of Blessed Pauline Jaricot-a French missionary figure-was carried out in 2022. As tandem mass spectrometry proteotyping has proven to be valuable to obtain the broad taxonomic repertoire of a given sample without any a priori information, we aimed at exploring the conditions of preservation of the relics and possible conditions of death. Metaproteomics and high-resolution microtomography imaging approaches were combined. A dataset comprising 6731 high-resolution MS/MS spectra was acquired and 968 of these spectra could be assigned to specific peptidic biomolecules. Based on the taxonomical information encompassed by the identified peptide sequences, 5 phyla were identified amongst eukaryota (94% of the biomass): Ascomycota (55%), with the species Aspergillus versicolor, Trichophyton mentagrophytes and Aspergillus glaucus, corresponding to expected cadaverous fungal flora; Chordata (42%), represented by a unique species, Homo sapiens; Streptophyta (3%); and Arthropoda (traces). Bacteria (6% of the biomass) were poorly represented. No trace of embalming substance could be retrieved, nor any pathogens. Imaging evidenced no heart defect nor embalming traces. No evidence that was inconsistent with natural and spontaneous conservation could be retrieved. This study prefigures the power of modern molecular techniques such as paleoproteotyping coupled to microtomography to gain insight into historical relics.

Experimental CO2 interactions with fractured Utica and Marcellus Shale samples at elevated pressure

Experiments showed that 5% KI carbonated brine injection into fractured Marcellus and Utica Shale cores at room temperature (∼20 °C) and at 1700 psi (MPa) confining pressure resulted in dissolution along fractures, together with an increase in the total core permeability of the fractured cores. Dissolution in the more calcium-rich Utica Shale concentrated along larger aperture zones that likely channeled the bulk of the flow through the core. In contrast, dissolution in the Marcellus Shale sample was more uniform across the fracture plane and accompanied by the development of a porous, permeable zone of partial dissolution within the shale matrix that developed throughout the sample and decreased in volume along core length. X-ray fluorescence measurements in both cores revealed depletion in calcium, and in the Marcellus core the composition of the porous reaction rind was non-reactive and silica rich. The partial dissolution of the Marcellus Shale matrix adjacent to the fracture resulted in a permeable zone that contributed to the sample's increased transmissivity, as shown by fracture aperture mapping, high-resolution microtomography, and numerical simulations of flow through the fracture. Shale lithology and mineralogy were combined with the initial fracture morphology to determine where, how, and to what degree reactive fluids caused changes to fractured shales. Although the experimentally determined macroscopic permeability of both cores increased approximately one order of magnitude, the different compositions of the rocks resulted in distinct microscopic dissolution patterns. The umbrella term of “shale” encompasses a variety of lithological compositions with variable reactive potential. Our analysis demonstrates that even small lithological variations in carbonate and silicate mineral content and distribution can have an outsized impact on shale fracture behavior during reactive flow. Any field-scale assessment of the utility of shales as sealing formations or reservoirs in the presence of reactive brines must entail a thorough description of the given lithological unit and its susceptibility to reactive flow.

基于&amp;lt;bold&amp;gt;CT&amp;lt;/bold&amp;gt;成像和数字体图像相关法的岩石内部变形场量测方法的研究进展

<p indent="0mm">Rock mechanics plays a critical role in mining engineering, slope engineering, tunnel engineering, water conservancy, hydropower engineering, and some newly developing rock mass engineering, such as deeply buried oil and gas storage, underground nuclear waste repository, geothermal development, etc. The evolution of the internal discontinuous structure of rock under the coupling of multiple physical fields such as stress field, seepage field, and temperature field is an important research topic in the field of rock mechanics. Scholars have investigated the internal structure characteristics and their evolution process at different scales with various equipment. High-resolution microtomography (Micro CT) with micron or even nanoscale resolution has been widely used in internal structure detection, digital core modeling, and numerical modeling of rock. The digital volume correlation (DVC) method can quantitatively analyze and visualize the internal 3D deformation field of rock, and its combination with Micro CT provides a new method for transparent analysis and deduction of discontinuous structures and multi-physical fields in rocks. This paper systematically reviews the research on internal deformation measurement of rocks by using Micro CT and DVC in terms of <italic>in-situ</italic> loading device with Micro CT, the theory of DVC, the influence of micro/meso-structures in rocks, and experimental measurements. To view the internal structures of rocks under different physical fields, various <italic>in-situ</italic> loading devices combined with Micro CT were developed, e.g., uniaxial loading device, triaxial loading coupled with seepage device, gas adsorption device, and heating device. In these devices, factors such as the strength of rock, physical field, material strength of chamber, X-ray energy and penetration, real-time performance of image acquisition, and quality of reconstructed images should be comprehensively considered. By using <italic>in-situ</italic> loading devices and Micro CT, a series of volume images of rocks are obtained before and after deformation, and then DVC is adopted to calculate the three-dimensional deformation field by analyzing the correlation between these volume images. According to the registration algorithms, DVC can be categorized into local DVC (L-DVC) and global DVC (G-DVC). The basic principle and development of DVC are reviewed. Due to the limitation of the heterogeneity of rocks and the accuracy of the image acquisition equipment, natural micro structures in rocks do not have ideal speckle patterns, which affects the accuracy of DVC. It is indicated that the larger the average gray gradient and Shannon entropy and the smaller the structural variation coefficient of a rock image, the higher the accuracy of DVC. The accuracy of G-DVC is slightly better than that of L-DVC, but its calculation efficiency is lower, especially when the mesh size is small. The applications of DVC for investigating strain localization in rocks, measuring carbon dioxide-induced strain in coal, and oil shale pyrolysis are presented. Despite some impressive achievements, DVC is still faced with some core challenges, e.g., the low accuracy of the DVC algorithm and artifact error correction, the influence of the microstructures in rocks, parameter identification and numerical model verification of rocks, and deformation field measurement under the coupling of multiple physical fields. With the popularization of Micro-CT in laboratories, DVC will be further applied to measuring the three-dimensional deformation field in rocks.

Shape analysis of the StW 578 calotte from Jacovec Cavern, Gauteng (South Africa)

The fossiliferous deposits within the lower-lying Jacovec Cavern in the locality of Sterkfontein yielded valuable hominin remains, including the StW 578 specimen. Because StW 578 mainly preserves the calotte, the taxonomic status of this specimen has been a matter of discussion. Within this context, here we employed high-resolution microtomography and a landmark-free registration method to explore taxonomically diagnostic features in the external surface of the StW 578 calotte. Our comparative sample included adult humans and common chimpanzees as well as one Australopithecus africanus specimen (Sts 5). We partially restored the StW 578 calotte digitally and compared it to extant specimens and Sts 5 using a landmark-free registration based on smooth and invertible surface deformation. Our comparative shape analysis reveals morphological differences with extant humans, especially in the frontal bones, and with extant chimpanzees, as well as intriguing specificities in the morphology of the StW 578 parietal bones. Lastly, our study suggests morphological proximity between StW 578 and Sts 5. Given the intimate relationship between the brain and the braincase, as well as the integration of the hominin face and neurocranium, we suggest that cranial vault shape differences between StW 578 and extant humans, if confirmed by further analyses, could be either explained by differences in brain surface morphology or in the face. Besides providing additional information about the morphology of the Jacovec calotte that will be useful in future taxonomic discussion, this study introduces a new protocol for the landmark-free analysis of fossil hominin cranial shape. Significance: We provide further information on the enigmatic fossil specimen StW 578. We introduce a new approach for the morphological study of fossil hominin crania. We highlight morphological similarities between StW 578 and ‘Mrs Ples’.

Oil-water interactions in porous media during fluid displacement: Effect of potential determining ions (PDI) on the formation of in-situ emulsions and oil recovery

Emulsification is a naturally occurring phenomenon during the multiphase flow. The amount of emulsion, its composition and rate of degradation can significantly affect the flow properties and subsequent oil recovery. In addition, fluid-fluid interactions were suggested as a controlling mechanism for enhancing the oil recovery by modified salinity brines. In this study, we have used high-resolution microtomography to visualise emulsions formed in heterogeneous carbonate rocks by seawater and ion-tuned brines. Additionally, interfacial tension and emulsion stability were studied in a laboratory environment to develop further understanding of the effect of naturally occurring (in absence of surfactant agents) in-situ emulsions on Enhanced Oil Recovery (EOR) at pore-scale. Our results show that emulsions that are formed in pores have varying compositions depending on pore geometries, wetting properties of the rock surface and ionic composition of the injected brines. In-situ emulsification has shown to be a contributing factor to the oil recovery enhancement, however, other mechanisms, such as wettability alteration plays an important role. Emulsion cluster sizes show log bimodal distribution and injection of ion tuned brines mostly contribute to improving the connectivity between the clusters and subsequent sweep efficiency of the waterflooding.

Thermal History of Matrix Forsterite Grains from Murchison Based on High-resolution Tomography

Abstract Protoplanetary disks are dust- and gas-rich structures surrounding protostars. Depending on the distance from the protostar, this dust is thermally processed to different degrees and accreted to form bodies of varying chemical compositions. The primordial accretion processes occurring in the early protoplanetary disk such as chondrule formation and metal segregation are not well understood. One way to constrain them is to study the morphology and composition of forsteritic grains from the matrix of carbonaceous chondrites. Here, we present high-resolution ptychographic X-ray nanotomography and multimodal chemical microtomography (X-ray diffraction and X-ray fluorescence) to reveal the early history of forsteritic grains extracted from the matrix of the Murchison CM2.5 chondrite. The 3D electron density maps revealed, at unprecedented resolution (64 nm), spherical inclusions containing Fe–Ni, very little silica-rich glass and void caps (i.e., volumes where the electron density is consistent with conditions close to vacuum) trapped in forsterite. The presence of the voids along with the overall composition, petrological textures, and shrinkage calculations is consistent with the grains experiencing one or more heating events with peak temperatures close to the melting point of forsterite (∼2100 K), and subsequently cooled and contracted, in agreement with chondrule-forming conditions.

Microbiological and micro‐computed tomography analysis of natal teeth: a case report

The aim of this study was to report a clinical case of a natural tooth found in a 1-day-old newborn, its clinical implications and proper management. The female patient was referred by a pediatrician who contacted the University of Ribeirão Preto Pediatric Dentistry Clinic (UNAERP, Ribeirão Preto, Brazil), informing that the patient with 40 hours of life, still in the maternity ward, had a foreign body in the oral cavity since birth, which was bothering the mother at the time of breastfeeding. At clinical examination, the presence of a Christmas tooth with grade 3 mobility was observed. After one month of life, it was possible to perform a radiographic examination, which resulted in the definitive diagnosis of the Christmas tooth, and the proposed treatment was the surgical removal of the dental element and subsequent follow-up. Prior to surgical removal, the biofilm present on the coronary surface was aseptically collected for microbiological analysis consisting of isolating the bacteria in different culture media and identifying them by sequencing 16S rRNA. The extracted tooth was scanned in high-resolution microtomography, reconstructed, and qualitatively analyzed. Microbiological analyses showed the presence of two bacterial species Streptococcus salivarius and Staphylococcus hominis, both species considered saprophytes, being part of the oral microbiota. The knowledge of this anomaly and the training of dentists to perform an accurate diagnosis, as well as the importance of multidisciplinary work, are of extreme relevance.

Illuminating the Brain With X-Rays: Contributions and Future Perspectives of High-Resolution Microtomography to Neuroscience.

The assessment of three-dimensional (3D) brain cytoarchitecture at a cellular resolution remains a great challenge in the field of neuroscience and constant development of imaging techniques has become crucial, particularly when it comes to offering direct and clear obtention of data from macro to nano scales. Magnetic resonance imaging (MRI) and electron or optical microscopy, although valuable, still face some issues such as the lack of contrast and extensive sample preparation protocols. In this context, x-ray microtomography (μCT) has become a promising non-destructive tool for imaging a broad range of samples, from dense materials to soft biological specimens. It is a new supplemental method to be explored for deciphering the cytoarchitecture and connectivity of the brain. This review aims to bring together published works using x-ray μCT in neurobiology in order to discuss the achievements made so far and the future of this technique for neuroscience.

Obturación endodóntica de las raíces mesiales de molares inferiores con sellador Bio-C Sealer y AHPlus

La obturación del conducto radicular se realiza con conos de gutapercha y un sellador endodóntico, el cual rellena los espacios entre la pared dentinaria y el material obturador; y las irregularidades del conducto radicular. El sellador Bio-C Sealer es un cemento biocerámico con propiedades bioactivas, mientras que el sellador AH Plus es un cemento a base de resina. La hipótesis del presente estudio fue que el sellador Bio-C Sealer ocupa mayor volumen y superficie, respecto del sellador AH Plus.OBJETIVO: Comparar el uso del sellador Bio-C Sealer con el sellador AH Plus en la obturación de conductos mesiales de molares inferiores.MATERIALES Y MÉTODOS: Se seleccionaron 40 conductos (20 mesio-vestibulares y 20 mesio-linguales) de 20 raíces mesiales de molares inferiores permanentes. Los conductos fueron instrumentados con limas Wave One Gold Small (Dentsply, Maillefer) y WaneOne Gold Primary e irrigados con hipoclorito de sodio. Para la obturación, la muestra se dividió en dos grupos de 20 conductos cada uno, de acuerdo al sellador endodóntico utilizado. Grupo A: sellador AH Plus (Dentsply, Maillefer) y Grupo B: sellador Bio-C Sealer (Angelus). Finalizada la obturación, se utilizó la microtomografía computada (micro-CT) de alta resolución con un detector tipo flat-panel certificado de la compañía Varian R (USA) modelo PaxScan 2020+ para obtener 180 proyecciones tomográficas de cada muestra. Luego se reconstruyó la imagen 3D de la muestra utilizando algoritmos específicos dedicados en el software MatLab (MathWorks, USA), y con desarrollos propios del equipo de investigación en lenguaje Python en las instalaciones del LIIFAMIRx de la Universidad Nacional de Córdoba. Los datos obtenidos fueron analizados estadísticamente mediante el test de Mann Whitney.RESULTADOS: No se encontraron diferencias significativas en el volumen de obturación entre las muestras tratadas con sellador AH Plus y sellador Bio C- Sealer (p&gt;0,05). Respecto al volumen de espacios vacíos, la frecuencia de casos en los cuales pudieron detectarse volúmenes de vacíos mensurables (≥ 0,01 mm3) fue del 15%; registrándose 2 en el grupo BIO-C sealer (5%) y 4 en AH Plus (10%). CONCLUSIÓN: Bajo las condiciones de este estudio, puede concluirse que ambos selladores AH Plus y Bio-C Sealer resultaron adecuados para la obturación de los conductos mesio-vestibulares y mesio-linguales de molares inferiores. Sin embargo, el volumen de espacios vacíos fue menor cuando se usó el sellador biocerámico Bio-C Sealer.

Effect of capillary number on morphological characterizations of trapped gas bubbles: Study by using micro-tomography

A series of capillary trapping experiments were conducted in unconsolidated porous media using high-resolution micro-tomography. Morphological characterizations of trapped gas bubbles, including residual gas saturation, bubble size distribution and interfacial area, were determined from reconstructed three-dimensional images. Different flooding flow rates, corresponding to capillary number ranges from 1.0 × 10−7 to 3.8 × 10−4, were performed to investigate the impact of flow rate on these characterizations during imbibition processes. At low capillary number, where capillary forces are dominant, the residual gas saturation is independent of capillary number and the bubble size distribution shows a universal power-law behavior predicted from percolation theory. When the capillary number increases above a critical value, the residual saturation decreases sharply, and the bubble size distribution no longer exhibits power-law behavior. As capillary number increases, the volume fraction of single-pore bubbles increases from about 16% to more than 80%. Furthermore, we explored the interfacial area of trapped bubbles, including gas–solid and gas–water (meniscus) interfacial areas, which directly affect the mass transfer process inside porous media. The specific interfacial area exhibits a linear relation with residual saturation, and the effect of particle size can be normalized by multiplying the median particle diameter. Moreover, we observed that the meniscus/total interfacial area ratio increases from 0.61 to 0.78 with an increase in capillary number, because the smaller singlet has a higher interfacial contact with the wetting phase.

Soft tissue discrimination with contrast agents using micro-CT scanning

The use of high resolution, three-dimensional visualization has been receiving growing interest within life sciences, with non-invasive imaging tools becoming more readily accessible. Although initially useful for visualizing mineralized tissues, recent developments are promising for studying soft tissues as well. Especially for micro-CT scanning, several X-ray contrast enhancers are performant in sufficiently contrasting soft tissue organ systems by a different attenuation strength of X-rays. Overall visualization of soft tissue organs has proven to be possible, although the tissue-specific capacities of these enhancers remain unclear. In this study, we tested several contrast agents for their usefulness to discriminate between tissue types and organs, using three model organisms (mouse, zebrafish and Xenopus). Specimens were stained with osmium tetroxide (OsO4), phosphomolybdic acid (PMA) and phosphotungstic acid (PTA), and were scanned using high resolution microtomography. The contrasting potentials between tissue types and organs are described based on volume renderings and virtual sections. In general, PTA and PMA appeared to allow better discrimination. Especially epithelial structures, cell-dense brain regions, liver, lung and blood could be easily distinguished. The PMA yielded the best results, allowing discrimination even at the level of cell layers. Our results show that those staining techniques combined with micro-CT imaging have good potential for use in future research in life sciences.

Engineering the interfacial adhesion in basalt/epoxy composites by plasma polymerization

In an attempt to improve mechanical properties of basalt fibre/epoxy composites, the present work provides a comparison between the effects of a commercial coupling agent, a thermal de-sizing treatment and a plasma polymerization process on the fibre/matrix interfacial strength. The different basalt fibres were characterized in terms of surface morphology, by FE-SEM observations, and chemical composition, performing FT-IR analysis. The interfacial adhesion has been investigated by single fibre fragmentation test on single filament composite samples. The plasma polymerization process was able to produce a homogeneous tetravinylsilane (pp-TVS) coating on the surface of basalt fibres, which resulted in a significant increase in the fibre/matrix adhesion. The surface roughness of the untreated and treated basalt fibres has been measured by AFM and a relationship between the surface roughness and the fibre/matrix adhesion quality was found. High-resolution microtomography (µ-CT) has been used to support the analysis of the damage modes during fragmentation tests.

Synchrotron radiation micro-tomography for high-resolution neurovascular network morphology investigation.

There has been increasing interest in using high-resolution micro-tomography to investigate the morphology of neurovascular networks in the central nervous system, which remain difficult to characterize due to their microscopic size as well as their delicate and complex 3D structure. Synchrotron radiation X-ray imaging, which has emerged as a cutting-edge imaging technology with a high spatial resolution, provides a novel platform for the non-destructive imaging of microvasculature networks at a sub-micrometre scale. When coupled with computed tomography, this technique allows the characterization of the 3D morphology of vasculature. The current review focuses on recent progress in developing synchrotron radiation methodology and its application in probing neurovascular networks, especially the pathological changes associated with vascular abnormalities in various model systems. Furthermore, this tool represents a powerful imaging modality that improves our understanding of the complex biological interactions between vascular function and neuronal activity in both physiological and pathological states.

Masseter muscle atrophy impairs bone quality of the mandibular condyle but not the alveolar process early after induction.

Masseter muscle function influences mandibular bone homeostasis. As previously reported, bone resorption markers increased in the mouse mandibular condyle two days after masseter paralysis induced with botulinum toxin type A (BoNTA), followed by local bone loss. This study aimed to evaluate the bone quality of both the mandibular condyle and alveolar process in the mandible of adult mice during the early stage of a BoNTA-induced masseter muscle atrophy, using a combined 3D histomorphometrics and shape analysis approach. Adult BALB/c mice were divided into an untreated control group and an experimental group; the latter received one single BoNTA injection in the right masseter (BoNTA-right) and saline in the left masseter (Saline-left). 3D bone microstructural changes in the mandibular condyle and alveolar process were determined with high-resolution microtomography. Additionally, landmark-based geometric morphometrics was implemented to assess external shape changes. After 2weeks, masseter mass was significantly reduced (P-value <0.001). When compared to Saline-left and untreated condyles, BoNTA-right condyles showed significant bone loss (P-value <0.001) and shape changes. No significant bone loss was observed in the alveolar processes of any of the groups (P-value >0.05). Condyle bone quality deteriorates at an early stage of BoNTA-induced masseter muscle atrophy, and before the alveolar process is affected. Since the observed bone microstructural changes resemble those in human temporomandibular joint degenerative disorders, the clinical safety of BoNTA intervention in the masticatory apparatus remains to be clarified.

Interfacial adhesion assessment in flax/epoxy and in flax/vinylester composites by single yarn fragmentation test: Correlation with micro-CT analysis

Despite the academic interest in using plant fibres as reinforcement in polymer composites to replace glass fibres, the industrial exploitation of resulting composites in semi- or structural applications is still limited. This is mainly due to the poor adhesion at the plant fibre/polymer matrix interface dictated by their surface chemistry and strong hydrophilic behaviour. In the present work, an assessment of the interfacial adhesion at the yarn scale has been carried out. Fragmentation tests have been performed on flax/epoxy and flax/vinylester single yarn composites. High-resolution microtomography has allowed a 3-D reconstruction of the breaking area of the flax yarn. The flax/epoxy system has shown the lowest values of critical fragment length and interfacial debonding length, and the highest values of IFSS. For both epoxy and vinylester samples, it was found that the breakage of flax has been mainly concentrated in the peripheral zone of the yarn.