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Purpose: To investigate bone regeneration among three different bone graft materials in a rat calvarum model. Materials and Methods: A total of 24 rats had two 5-mm defects placed per calvarial. Rats were divided into four groups: bovine xenograft (XG), demineralized bone matrix (DBM), mineralized bone graft (MBG), and collagen membrane control (CC). Within each group, samples were collected at two time points: 4 weeks (T4) and 8 weeks (T8). Bone regeneration was assessed by microcomputed tomography (micro-CT) imaging and was analyzed using MATLAB software. Additionally, the fixed samples were subsequently demineralized for immunohistochemistry and histomorphometry. Slides were mounted and stained with hematoxylin and eosin (H&E) stain as well as bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (RUNX2) markers. The numbers of positive cells/area were calculated for each group and analyzed. Results: At 4 weeks, DBM showed low mineral density (7.7%) compared to the control (25.2%), but increased dramatically at 8 weeks (DBM, T8 = 27.6%; CC, T8 = 27.2%). Xenograft material showed an increase in mineral desnity between T4 and T8 (XG, T4 = 25.0%; XG, T8 = 32.3%). MBG remained consistent over the 8-week trial period (MBG, T4 = 30.4%; MBG, T8 = 30.4%). BMP-2 expression was present in cells adherent to all graft materials. RUNX2 expression was also observed in cells adherent to all graft materials, indicating that during the 4- to 8-week healing period, all materials supported osteogenesis. Conclusions: Compared to other materials, the DBM had high osteoinductive properties during the 4- to 8-week time period based on increased mineral content. All materials were associated with immunohistologic evidence of osteogenesis in the rat calvarial defect model. [ABSTRACT FROM AUTHOR]

X-ray-based computed tomography is a well established technique for determining the three-dimensional structure of an object from its two-dimensional projections. In the past few decades, there have been significant advancements in the brightness and detector technology of tomography instruments at synchrotron sources. These advancements have led to the emergence of new observations and discoveries, with improved capabilities such as faster frame rates, larger fields of view, higher resolution and higher dimensionality. These advancements have enabled the material science community to expand the scope of tomographic measurements towards increasingly in situ and in operando measurements. In these new experiments, samples can be rapidly evolving, have complex geometries and restrictions on the field of view, limiting the number of projections that can be collected. In such cases, standard filtered back-projection often results in poor quality reconstructions. Iterative reconstruction algorithms, such as model-based iterative reconstructions (MBIR), have demonstrated considerable success in producing high-quality reconstructions under such restrictions, but typically require high-performance computing resources with hundreds of compute nodes to solve the problem in a reasonable time. Here, tomoCAM, is introduced, a new GPU-accelerated implementation of model-based iterative reconstruction that leverages non-uniform fast Fourier transforms to efficiently compute Radon and back-projection operators and asynchronous memory transfers to maximize the throughput to the GPU memory. The resulting code is significantly faster than traditional MBIR codes and delivers the reconstructive improvement offered by MBIR with affordable computing time and resources. tomoCAM has a Python front-end, allowing access from Jupyter-based frameworks, providing straightforward integration into existing workflows at synchrotron facilities.

Scalp hair is a key feature of humans and its variability has been the subject of a broad range of studies. A small subset of these studies has focused on geometric quantification of human scalp hair fibres, however the use of race‐ and ethnicity‐based classification systems makes it challenging to draw objective conclusions about fibre variability. Furthermore, sample preparation techniques for micro‐imaging studies often alter the original form of hair fibres. This study sought to determine which of the commonly reported descriptors could be resolved using micro‐computed tomography (micro‐CT) for fibres of varying curl. Images obtained from micro‐CT were used to reconstruct three‐dimensional images that were then analysed. The study also explored the capabilities and limitations of micro‐CT as an imaging modality by comparing and cross‐validating findings with those obtained from scanning electron microscopy (SEM) and laser micrometry. The former deals with surface imaging while the latter deals with cross‐sectional measurements. Micro‐CT was found to be highly effective at resolving cross‐sectional ellipsoidal parameters, but performed more poorly than SEM in reconstructing surface level details at a 2 μm$\umu\text{m}$ resolution. The technique was, however, able to reveal the presence of the medulla in type VI (high curl) hair fibres. When compared with high curl fibres, greater intra‐fibre variability was observed for the low and medium curl fibres, highlighting the importance more objective classification systems. [ABSTRACT FROM AUTHOR]

Epoxy-nanomaterials offer a promising solution to combat corrosion threatening civil infrastructure. To examine the impact of nano silica on corrosion resistance, varying amounts of nano silica, ranging from 0.0 to 3 wt%, were introduced into the epoxy matrix. Mechanical properties were studied through studying the dog-bone tensile strength and tribological aspects were assessed through mass loss abrasion tests. Corrosion resistance performance was studied using electrochemical impedance spectroscopy (EIS) and salt spray tests. Nano structure of the coated specimens was studied after salt spray tests using SEM-EDX analysis. Micro Chromatography (M-Ct) technique was employed to investigate the pore formation in the epoxy matrix. Besides, atomic force microscopy (AFM) was introduced to study surface roughness. The test results displayed a notable improvement (5–10 %) in tensile strength upon the introduction of nano silica. Taber tester results showed a reduction in mass loss with the addition of nano silica. Electrochemical impedance spectroscopy (EIS) studies further established a significant increase in corrosion resistance, having an impedance of 12 GOhm.cm2 for epoxy matrix samples containing 2.5 % nano silica after a 768-h salt spray test. SEM-EDX analysis revealed the absence of iron content in the epoxy matrix reinforced with uniformly distributed nano silica. Surface roughness assessments illustrated that nanolaminates contributed to an increase in overall roughness, minimizing surface irregularities in the epoxy matrix. Micro-CT scanning results proposed a decrease in epoxy matrix porosity upon the addition of nano silica. AI based prediction model helped to understand the relationship between surface roughness and corrosion. In summary, the experimental findings suggest valuable insights for future advancements in the development of protective coatings for worldwide civil infrastructures. [ABSTRACT FROM AUTHOR]

The transverse dimensions of internasal and nasopremaxillary sutures in rats were assessed at different ages and following different dietary functional demands.Eighty‐four male Wistar rats were divided into two groups fed either a hard or a soft diet from 4 weeks of age, and sacrificed at 4 weeks (baseline: n = 12),16 weeks (n = 24), 26 weeks (n = 24), or 38 weeks (n = 24) of age. High‐resolution micro‐computed tomograms of the internasal and left nasopremaxillary sutures were obtained with 10 µm voxel size and 5 × 5 mm field of view. The endocranial and ectocranial suture widths, the mean suture width, and the suture height were measured. Linear regression analysis was used to estimate the effects of age and type of diet on suture dimensions. Internasal and nasopremaxillary suture dimensions were influenced by age, with a generally lower width and a larger height in the older animal. Regarding diet consistency, internasal suture widths were on average larger in the hard‐diet group (e.g., mean suture width 43 µm in the hard‐ versus 30 µm in the soft‐diet group at 26 weeks). In conclusion, the internasal and nasopremaxillary sutures tend to become narrower with age, while being influenced by masticatory functional demands. [ABSTRACT FROM AUTHOR]

Background: Adult growth hormone deficiency (AGHD) is associated with an increased risk of fractures and impaired bone microstructure. Understanding the metabolic changes accompanying bone deterioration in AGHD might provide insights into mechanisms behind molecular changes and develop new biomarkers or nutritional strategies for bone destruction. Our study aimed to investigate the association between altered metabolite patterns and impaired bone microstructure in adult rats with growth hormone deficiency. Methods: Thirty seven-week-aged adult Lewis dwarf homozygous (dw/dw) rats (five females and five males), and adult Lewis dwarf heterozygous (dw/ +) rats (five females and five males) rats were compared. Micro-computed tomography (Micro-CT) was used to examine the bone's microstructure. Hematoxylin and eosin (H&E) staining were used to quantify the histological characteristics. Liquid chromatography-mass spectrometry untargeted serum metabolomic analysis was applied in the study. ELISA was used to measure serum bone turnover markers and IGF-1 levels. Results: Adult dw/dw rats exhibited great reductions in trabecular volume bone density (Tb.vBMD), bone volume/total volume (BV/TV), and cortical thickness (Ct. Th) compared with adult dw/ + rats (all p values < 0.05), indicating significant impairment in bone microstructure. The serum metabolite profiles revealed substantial differences between the dw/dw rats and dw/ + rats. A total of 134 differential metabolites in positive ion mode and 49 differential metabolites in negative mode were identified. Five metabolites, including Lysophosphatidylcholine(LPC) 20:3, LPC22:6, LPC22:4, cortisol and histamine levels were upregulated in dw/dw rats. The steroid hormone biosynthesis and bile secretion pathways were the main perturbed metabolic pathways. There were significant associations between differential metabolites and the impaired bone microstructure parameters, indicating that the selected metabolites might serve as potential biomarkers for deteriorated bone microstructure in AGHD. Conclusion: Adult dw/dw rats exhibit impaired bone microstructure and distinct serum metabolic profiles, and the altered metabolites were significantly associated with bone microstructure destruction. This provides a new insight into understanding the mechanism of bone deterioration in AGHD patients from a metabolic perspective. [ABSTRACT FROM AUTHOR]

Traditional approaches to the human cochlear nerve have been impeded by its bony encasement deep inside the skull base. We present an innovative, minimally invasive, therapeutic pathway for direct access to the nerve to deliver novel regenerative therapies. Neuroanatomical studies on 10 cadaveric human temporal bones were undertaken to identify a potentially safe therapeutic pathway to the cochlear nerve. Simulations based on three-dimensional delineation of anatomical structures obtained from synchrotron phase-contrast imaging were analyzed. This enabled the identification of an approach to the nerve in the fundus of the internal auditory meatus by trephining the medial modiolar wall of the cochlea via the round window for a median depth of 1.48 mm (range 1.21–1.91 mm). The anatomical access was validated on 9 additional human temporal bones using radio-opaque markers and contrast injection with micro-computed tomography surveillance. We thus created an effective conduit for the delivery of therapeutic agents to the cochlear nerve. [ABSTRACT FROM AUTHOR]

This study presents a novel multi-technique approach that integrates micro-CT and optical photothermal infrared spectroscopy (O-PTIR) to evaluate polymerisation differences, so-called spatio-temporal polymerisation properties, between flowable and sculptable dental resin-based composites. Ten commercially available dental composites were investigated, including flowable and sculptable counterparts from the same manufacturer. Eight parameters were evaluated: short-term polymerisation characteristics (degree of conversion after 5 min, maximum polymerisation rate, time to reach maximum polymerisation rate) was measured using ATR-FTIR with real-time monitoring; changes in the degree of conversion with depth were evaluated with O-PTIR, 3D visualisation of shrinkage patterns, overall volumetric shrinkage, depth-specific shrinkage, and porosity were measured using micro-CT; surface morphology with detailed measurements of elemental composition was characterised using SEM/EDX; light transmittance was analysed with a NIST-referenced spectrometer. The study found that the increase in filler weight and volume ratio reduced the degree of conversion and polymerisation shrinkage, while moderately influencing the maximum polymerisation rates. The time to reach maximum polymerisation rates and light transmittance were not dependent on the filler amount. O-PTIR assessed a depth-dependent decrease in the degree of conversion for both composite types, with flowable composites generally showing a greater decrease in the degree of conversion than sculptable composites, except for bulk-fill composites. Micro-CT scans showed significantly higher flowable shrinkage values than their sculptable counterparts, highlighting the performance differences between the two types of composites. The findings of this study have practical implications for the selection and use of dental composites. Flowable composites, despite their higher degrees of conversion and polymerisation rates, also exhibit higher volumetric shrinkage, which can be detrimental for clinical applications. The new measurement methods used in this study provide a comprehensive overview of the polymerisation behaviour of commercially available dental composites, offering valuable insights for material optimisation. [ABSTRACT FROM AUTHOR]

Dental resin composites' performance is intricately linked to their polymerisation shrinkage characteristics. This study compares polymerisation shrinkage using advanced 3D micro-computed tomography (micro-CT) and traditional 2D linear assessments. It delves into the crucial role of filler content on shrinkage and the degree of conversion in dental resin composites, providing valuable insights for the field. Five experimental dental composite materials were prepared with increasing filler contents (55–75 wt%) and analysed using either 3D micro-CT for volumetric shrinkage or a custom-designed linometer for 2D linear shrinkage. The degree of conversion was assessed using Optical Photothermal Infrared (O-PTIR) and Fourier-Transform Infrared (FTIR) spectroscopy. Light transmittance through a 2-mm layer was evaluated using a NIST-calibrated spectrometer. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) examined surface morphology and elemental distribution. Correlation between the investigated parameters was determined using Spearman correlation analyses. The study found significant differences in polymerisation-related properties among different filler content categories, with volumetric shrinkage consistently demonstrating higher mean values than linear shrinkage across most groups. Volumetric shrinkage decreased with increasing curing depth, showing no direct correlation between filler content and shrinkage levels at different curing depths. The results highlighted a strong negative correlation between filler content and degree of conversion, volumetric and linear shrinkage, as well as maximum shrinkage rate. Light transmittance showed a moderate correlation with the filler content and a weak correlation with other tested parameters. This study underscores the importance of considering both volumetric and linear shrinkage in the design and analysis of dental composite materials. The findings advocate optimising filler content to minimise shrinkage and enhance material performance. Integrating micro-CT and O-PTIR techniques offers novel insights into dental composites' polymerisation behaviour, providing a foundation for future research to develop materials with improved clinical outcomes. • 3D micro-CT and O-PTIR spectroscopy provide novel insights into dental composite polymerisation. • Filler content significantly influences polymerisation shrinkage and degree of conversion. • Volumetric shrinkage was consistently higher than linear shrinkage in most experimental groups. • Increasing filler content reduced shrinkage and improved material performance. • Integration of micro-CT and O-PTIR techniques advances understanding of dental composites. [ABSTRACT FROM AUTHOR]

The vascular bundle in the ear-internode of maize is a key conduit for transporting photosynthetic materials between "source" and "sink", making it critically important to examine its micro-phenotypes and genetic architecture to identify advantageous characteristics and cultivate high-yielding and high-quality varieties. Unfortunately, the limited observation methods and scope of study precludes any comprehensive and systematic investigations into the microscopic phenotypes and genetic mechanisms of vascular bundle in maize ear-internode. In this study, 47 phenotypic traits were extracted in 495 maize inbred lines using micro computed tomography (Micro-CT) scanning technology and a deep learning-based phenotype acquisition method for stem vascular bundle, which included stem slice-related, epidermis zone-related, periphery zone-related, inner zone-related and vascular bundles-related traits. Phenotypic analysis indicated that there was extensive phenotypic variation of vascular bundle traits in ear-internode, especially that in the inner zone. Of these, 30 phenotypic traits with heritability greater than 0.70 were conducted for GWAS, and a total of 4,225 significant SNPs and 416 candidate genes with detailed functional annotations were identified. Furthermore, 20 genes were highly expressed in stem-related tissues, especially in maize internodes. Functional analysis of candidate genes indicated that the pathways obtained for candidate genes of different trait groups were distinct, mainly involved in vitamin synthesis and metabolism, transport of substances, carbohydrate derivative catabolic process, protein transport and localization, and anatomical structure development. The results of this study will help to further understand the phenotypic traits of stem vascular bundles and provide a reference for revealing the genetic mechanism of maize ear-internode vascular bundles. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the amount of apically extruded debris and to determine the remaining filling material on the root canal walls by microcomputed tomography (micro-CT), following the root canal retreatment of root canals filled with different obturation techniques (single cone technique, thermoplasticised injection technique) and the different root canal sealers [bioceramic-based, epoxy resin-based root canal sealer]. Materials and methods: 60 single rooted human premolar teeth were prepared with the ProTaper Gold system (Dentsply Maillefer) up to the F4 file and the samples were divided into 4 groups according to obturation procedures: Single cone technique + AH Plus sealer(epoxy resin-based root canal sealer, Dentsply International Inc., York, PA, USA); Single cone technique + Sure-Seal Root(bioceramic-based root canal sealer, Sure Dent Corporation, Gyeonggi-do, South Korea); thermoplastic injection technique[Calamus Dual Obturation System(Dentsply-Tulsa Dental, Tulsa, OK, USA)] + AH Plus(Dentsply International Inc.); Sure-Seal Root(Sure Dent Corporation) + Calamus Dual Obturation System (Dentsply-Tulsa Dental). The teeth were inserted into preweighed Eppendorf tubes and retreatment was performed. The tubes were kept in an incubator at 37 °C for 14 days to obtain the dry debris weight. Following the removal of the root canal fillings, the samples were scanned with a micro-CT device to analyse the volume of filling residues. Results: Retreatment of samples obturated with epoxy-resin or bioceramic based root sealers combined with Calamus system resulted in higher amount of apical extrusion compared to their combination with single cone technique (p = 0.026 for Single cone technique + AH Plus sealer vs Calamus + AH Plus sealer and p = 0.005 for Single cone technique + Sure-Seal root sealer vs Calamus + Sure-Seal root sealer). The most debris was observed in the Calamus + Sure-Seal root sealer group, the least debris was observed in the Single cone technique + AH Plus sealer group. The percentage of residues was the highest in the Single cone technique + Sure-Seal root sealer and the lowest in the Calamus + AH Plus sealer group, but there were no significant differences between groups (p = 0.463). Conclusions: No correlation was observed among the groups in terms of extruded debris and remnants inside the root canal. When combined with bioceramic based sealer, thermoplasticised injection technique did not affect the cleanliness of root canal walls; however, it increased its apical extrusion potential during retreatment. Clinical relevance: The obturation method does not play a role in the removability of bioceramic based root canal sealer, however the use of bioceramic-based root canal sealers with cold obturation techniques may be beneficial in preventing apical extrusion. [ABSTRACT FROM AUTHOR]

Over the past decade, there has been growing interest in the sedimentological community to use micro X‐ray computed tomography to analyse microfacies in sediment cores. However, little attention has been paid to the application of micro‐computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary structures. A novel application of micro‐computed tomography in lithified sediment‐gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep‐marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro‐computed tomography data the size of particles and their distribution throughout the sample is reconstructed in 3D permitting a better visualisation of sedimentary textures. Particle distributions computed from micro‐computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro‐computed tomography to evaluate grain‐size trends. Micro‐computed tomography is complemented with micro‐X‐ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro‐X‐ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro‐computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro‐computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures. [ABSTRACT FROM AUTHOR]

Protolipterna ellipsodontoides is a small bunodont South American native ungulate, generally considered an early litoptern, exclusively found in the Palaeogene Itaboraí Basin. Its dentition is well known; however, its mandibular morphology was only known by fragmentary materials. Here, we describe the first complete mandible of this species. A micro-CT scan reveals the first case of alveolus resorption in this putative early litoptern. Two accessory canals on the retromolar region are also described. Canals on the retromolar region are documented for other mammalian orders; however, this represents the first description of this feature for the Protolipternidae. Unlike more advanced litopterns, this species lacks specialisations related to strict herbivory, and its dental and mandibular morphology suggests an omnivore habit. A comparison with the mandible of another Itaboraian protolipternid, Miguelsoria parayirunhor, indicates the presence of different dietary specialisations. Body mass estimations for both species are also provided. [ABSTRACT FROM AUTHOR]

Highlights Fatigue damages of Carbon Fiber Reinforced Polymer (CFRP) laminates are not obvious. Obtaining the evolution of the internal fatigue damage in CFRP laminates before visible cracks occur is of vital importance for ensuring structural reliability. Micro X‐ray computed tomography (Micro‐CT) can provide micron scale nondestructive imaging of internal structure of materials. In this paper, a preliminary study was conducted on the early fatigue damage evolution of 0° UD laminates. Axial tension‐tension fatigue tests of [0]16 CFRP laminates were carried out, and the evolutionary behavior of damages was confirmed by fatigue dissipated energy. Then, the internal damages of fatigued specimens were observed and reconstructed using Micro‐CT, and statistical parameters such as damage sphericity, length and angle were calculated. The spatial distribution characteristics of cracks were further acquired by surface porosity and frequency distribution of damage positions in ROI. Early damages from tensile‐tensile fatigue in 0° UD laminates extend along the fiber direction with original defects in the interlayer resin enrichment areas as the nucleus, and tend to concentrate near the width edge of the specimens. Finally, a “sandwich” structural model was developed to analyze the internal stresses of laminates under the influence of interlayer resin enrichment. The FEA results revealed that the internal stresses σy and σz concentrate near the width edges of the specimen, resulting in cracks tend to evolve more in the regions close to edges. Imaging matrix cracks of specimens by Micro‐CT at 12.91 μm voxel size. Demonstrating evolution patterns of cracks with its morphology statistics. Revealing crack distributions in ROIs with variations of surface porosity. Analyzing internal stress distribution by “sandwich” model created from reality. [ABSTRACT FROM AUTHOR]

The randomized study aimed to evaluate the comparability of in situ (iS) and in vitro (iV) study protocols regarding remineralization of artificial enamel lesions. Two toothpastes (group A: 1450 ppm sodium fluoride, group B: placebo 0 ppm F-), were investigated. IV, a pH-cycling model with toothpaste slurry treatment was applied for 10d. IS, remineralization was performed in 9 participants wearing splints with embedded enamel samples for 10 and 21d, randomly allocated to groups A and B. Samples were scanned by X-ray micro-computed tomography (μCT) and grayscale value line profiles corresponding to mineral density (rel.ΔZ) were analyzed. Statistical analyses were performed using MedCalc Statistical Software, v22.021. T-Test for dependent and independent data and analysis of variance (ANOVA) were used for further analyses (α = 0.05). Rel.ΔZ of fluoride treated samples (A) were iV = 40.2%, iS 10d = 11.5% and iS 21d = 46.1% (p > 0.05). Rel.ΔZ of placebo treated samples (B) were: iV = − 6.2%, iS 10d = 25.2% and iS 21d = 11.0% (p > 0.05). Remineralization potential of both toothpastes was significantly different regarding iV (p < 0.001) and iS after 21d (p = 0.034), while in case of iS 10d no significant difference was detected (p = 0.4). Despite different study protocols the μCT results after remineralization were comparable between iV and iS. The results suggest that selected studies can be carried out in faster, simplified iV studies using pH-cycling instead of iS studies. [ABSTRACT FROM AUTHOR]

AbstractSeveral artefacts were found during the excavation performed at “Pozzo di Bellafonte”, located in an archaeological area in the province of Florence (Italy). The material found in the archaeological site included a large amount of wood samples; therefore, a method for understanding the positioning, the shape and the orientation of the wood sample vessels was necessary for identification of botanical taxa. In recent years, the study of ancient remains has benefited greatly from the use of imaging techniques commonly used for medical diagnosis and biomedical research, such as the micro-Computed Tomography (micro-CT) and high-field micro-Magnetic Resonance Imaging (micro-MRI). In this paper such imaging methodologies were employed for assessing the internal structure of representative wood samples extracted from the above mentioned. The complementarity of micro-CT and micro-MRI for the investigation of wood specimen anatomy is also discussed, by underlining what micro-MRI provides as compared with micro-CT and by proposing a tool constituted by the combination of micro-CT/micro-MRI for the study of such wood samples in a multimodal approach. [ABSTRACT FROM AUTHOR]

Mass transport in frozen ground is typically regarded slow. However, a highly permeable path can exist in frozen saline sand if the unfrozen water is interconnected at the pore scale. We therefore should consider when the unfrozen water is connected and how permeable can frozen saline sand be, yet there are few studies. This research utilizes in‐situ X‐ray CT to evaluate unfrozen water connectivity and permeability in frozen saline sand considering effects of initial salt content, temperature, freezing rate, and temperature gradient. Results show that higher initial salt content and/or temperature, both of which results in a higher unfrozen water content, easily maintains unfrozen water connectivity. Rapid freezing minimizes the brine expulsion and permits a higher unfrozen water content hence better connectivity. Permeability in frozen saline sand can be several orders higher than the typically reported value, highlighting the potential presence of rapid mass transport through the connected unfrozen water. Plain Language Summary: Frozen aqueous sandy soils in nature often contain a lot of substances such as dissolved salts, gases, contaminants. Mass migration via unfrozen water is of vital importance to groundwater flow, greenhouse gas emission, even contaminated soil remediation. Permeability determination of unfrozen water is well‐studied in salt‐free soils. Our study shows there can be a highly conductive path in frozen saline sand when the unfrozen water is interconnected, even at a low unfrozen water saturation of 14%. The connectivity of unfrozen water remains at −20°C with an initial salt concentration similar to seawater. Rapid freezing causes better connectivity because less unfrozen water is squeezed out of the frozen sand during ice growth. Permeability in frozen saline sand can be several orders of magnitude higher than the typically reported value. These findings indicate that mass transport in frozen ground, via the connected unfrozen water, can be much more active than previously thought. Key Points: Pore‐scale unfrozen water can be interconnected, enabling fast mass transport below 0°C when soil contains saltRapid freezing enhances unfrozen water connectivity and permeability due to less and slower salt migration during freezingPermeability of frozen saline sand can be several orders of magnitude higher than that of salt‐free soil [ABSTRACT FROM AUTHOR]

The anatomy of the avian lower respiratory system includes a complex interaction between air‐filled pulmonary tissues, pulmonary air sacs, and much of the postcranial skeleton. Hypotheses related to the function and phylogenetic provenance of these respiratory structures have been posed based on extensive interspecific descriptions for an array of taxa. By contrast, intraspecific descriptions of anatomical variation for these features are much more limited, particularly for skeletal pneumatization, and are essential to establish a baseline for evaluating interspecific variation. To address this issue, we collected micro‐computed tomography (μCT) scans of live and deceased African grey parrots (Psittacus erithacus) to assess variation in the arrangement of the lungs, the air sacs, and their respective invasion of the postcranial skeleton via pneumatic foramina. Analysis reveals that the two pairs of caudalmost air sacs vary in size and arrangement, often exhibiting an asymmetric morphology. Further, locations of the pneumatic foramina are more variable for midline, non‐costal skeletal elements when compared to other pneumatized bones. These findings indicate a need to better understand contributing factors to variation in avian postcranial respiratory anatomy that can inform future intraspecific and interspecific comparisons. [ABSTRACT FROM AUTHOR]

The intensive development of tight reservoirs has positioned them as a strategic alternative to conventional oil and gas resources. Existing enhanced oil recovery (EOR) methods struggle to effectively exploring reservoir oil, resulting in low recovery rates. Novel and effective means of developing tight reservoirs are urgently needed. Nanomaterials have shown promising applications in improving water flooding efficiency, with in-depth research into mechanisms that lower injection pressure and increase water injection volumes. However, the extent of improvement remains limited. In this study, a silicon quantum dots (Si-QDs) material was synthesized via a hydrothermal synthesis method and used to prepare a nanofluid for the efficient recovery of tight reservoir. The Si-QDs, with an approximate diameter of 3 nm and a spherical structure, were surface functionalized with benzenesulfonic acid groups to enhance the performance. The developed nanofluid demonstrated stability without aggregation at 120 °C and a salinity of 60000 mg/L. Core flooding experiments have demonstrated the attractive EOR capabilities of Si-QDs, shedding light of the EOR mechanisms. Si-QDs effectively improve the wettability of rocks, enhancing the sweeping coefficient of injected fluids and expanding sweeping area. Within this sweeping region, Si-QDs efficiently stripping adsorbed oil from the matrix, thus increasing sweeping efficiency. Furthermore, Si-QDs could modify the state of pore-confined crude oil, breaking it down into smaller particles that are easier to displacement in subsequent stages. Si-QDs exhibit compelling EOR potential, positioning them as a promising approach for effectively developing tight oil reservoirs. [ABSTRACT FROM AUTHOR]

To investigate the effect of different thickness ratios of the upper and lower panels on the foam aluminum sandwich panels, this paper conducts three-point bending tests. And use micro-CT technology to perform phased scans of the bending process in the experiment. The results show that, the collapse, splitting, and lateral extrusion of each cell are simultaneously present in three different forms of damage. At a span of 100mm, cell collapse dominates the damage deformation. At spans of 80mm and 60mm, splitting becomes the dominant factor. When the intrusion depth of the loading roller significantly increases, lateral extrusion damage becomes dominant. [ABSTRACT FROM AUTHOR]

Screw loosening is a common complication of pedicle screw internal fixation surgery. This study aimed to investigate whether the application of a porous scaffold structure can increase the contact area between screws and bone tissue by comparing the bone ingrowth and screw-bone interface of porous scaffold core pedicle screws (PSCPSs) and hollow lateral hole pedicle screws (HLHPSs) in the lumbar spine of Bama pigs. Sixteen pedicle screws of both types were implanted into the bilateral pedicles of the L1–4 vertebrae of 2 Bama pigs. All Bama pigs were sacrificed and the lumbar spine was freed into individual vertebrae at 16 weeks postoperatively. After the vertebrae were made into screw-centered specimens, micro-computed tomography analysis and histological observation were performed to assess the screw-bone interface and bone growth around and within the screws. We found that the bone condition around PSCPSs and HLHPSs did not show significant differences on micro-computed tomography three-dimensional reconstruction images. CT transverse views showed different bone growth inside the 2 screws. In PSCPSs, bone tissue was seen to fill the internal pores and was evenly distributed around each strut. Inside HLHPSs, bone growth was confined to 1 side of the screw and did not fill the entire cavity. Osteometric analysis showed that bone volume fraction and trabecular number, the parameters representing bone mass, were higher in PSCPSs than in HLHPSs. These differences were not statistically significant (P > 0.05). Histological observations visualized that the osseointegration within PSCPSs was superior to that of HLHPSs, and the tight integration of bone tissue with the porous scaffold resulted in a larger screw-bone integration area in PSCPSs than in HLHPSs. Compared with HLHPSs, PSCPSs possessing a porous scaffold core could promote bone ingrowth and osseointegration, resulting in an effective enhancement of the combined area of the screw-bone interface. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro investigation is to study the effect of endodontic cavity design on interfacial voids, class II resin composite sealing ability, and fracture resistance in mandibular premolars. Methods: A total of 48 single-rooted mandibular premolars received compound class II preparations with either traditional flare access cavities (group A) or contracted endodontic cavity preparations (group B). Each study group was subdivided according to the coronal restoration into two sub-groups as α and β. In the α group, a microhybrid composite was used after etch-and-rinse bonding technique using an MDP-containing universal adhesive. In the β group, a self-adhesive composite was used as coronal restoration after endodontic treatment (n = 12) for each subgroup. A micro-CT analysis was performed to assess the obturation interfacial voids and tracing of class II cervical interfacial adaptation. The tooth fracture resistance testing was then performed adding an extra group of 12 sound non-prepared teeth, which were tested as the control for fracture strength testing. A one-way ANOVA and post-hoc testing were used together with descriptive statistics for an analysis of the mean values of obturation interfacial voids. A two-way ANOVA was used to assess the fracture resistance test results, and to find the influence of endodontic access design and the type of composite material on the fracture resistance testing. Chi-square testing was employed to analyze the cervical interfacial seal of the class II restorations. Results: A one-way ANOVA revealed that there were no statistically significant differences between test groups in the amount of obturation interfacial voids (p > 0.05). There were no statistically significant differences between test groups in terms of cervical interfacial sealing ability (p > 0.05). A two-way ANOVA revealed that no statistically significant differences between test groups including the control group existed in terms of the fracture resistance testing (p > 0.05). Conclusions: Although it does not improve tooth fracture resistance, the contracted endodontic access cavity does not deteriorate the quality of obturation in terms of the interfacial porosity. The self-adhesive composite does not improve the efficiency of cervical interfacial adaptation or tooth fracture resistance regardless of the endodontic access cavity shape, yet it revealed a substantial load-bearing capacity. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of the estrogen depression during orthodontic tooth movement on alveolar bone microarchitecture and periodontal ligament. Female Wistar rats were divided into two groups, one consisting of non‐ovariectomized animals subjected to orthodontic tooth movement, and one comprising ovariectomized animals subjected to orthodontic tooth movement. Micro‐CT assessment of bone volume to total volume (BV/TV), total porosity, trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation (Tb.Sp) in the alveolar bone of the orthodontically moved tooth was performed. Histomorphometric analyses were made in the periodontal ligament, and immunoexpression of RANK, RANKL, OPG, and TUNEL were quantified. Orthodontic tooth movement in the group of ovariectomized rats was faster than in non‐ovariectomized animals. The alveolar bone area showed lower values of BV/TV and trabecular thickness, and higher bone porosity and trabeculae numbers in the ovariectomized rats. Histological analyses in the ovariectomized group revealed an increase in collagen fibers in the periodontal ligament. The apoptotic cell counts in the periodontal ligament were higher in the group of ovariectomized rats than in the sham‐operated rats. Ovariectomy resulted in an increase in tooth movement and alteration of the alveolar bone microstructure in the first 7 day of orthodontic tooth movement, and in the presence of apoptotic cells in the periodontal ligament. [ABSTRACT FROM AUTHOR]

Silicon Carbide (SiC) ceramic lattice structures were pivotal in advancing space technology and other sectors by merging structural lightness with high strength. This study explored non-uniform lattice designs tailored for specific load-bearing applications to maximize lightness, although machining such SiC structures proved challenging due to their high hardness and wear resistance. Selective Laser Sintering (SLS) was employed to fabricate non-uniform lattice structures featuring graded volume fractions. Micro computed tomography (Miro-CT) characterized the geometric characteristics of the macroscopic non-uniform lattice structure. Extensive investigations were conducted on the impact of these gradient structures on the quasi-static compressive behavior and mechanical properties of SiC ceramics, revealing that the R-A structure achieved a maximum compressive strength of 14.989 MPa and a specific strength of 13.268 × 10³ N·m/kg, approximately double that of a uniform structure. Furthermore, a finite element model (FEM) was established to verify and predict the mechanical and fracture responses of SiC-based structures, showing effective dispersion of stress concentration along the outer rim of the R-A structure, markedly alleviating the usual stress concentration found in traditional lattices and averting catastrophic failure. The alignment between experimental and simulation outcomes substantiated these findings. [Display omitted] [ABSTRACT FROM AUTHOR]

Endodontic retreatment procedures with calcium silicate-based sealers (CSS) have been receiving greater credibility in clinically challenging situations. The objective of this systematic review was to analyze the published in vitro studies for the retrievability of CSS in comparison to resin-based sealers evaluated using micro-computed tomography (micro-CT) in terms of the volume of the residual root canal filling materials, time taken, efficacy of the solvent, and different systems used during the retreatment procedure. The study protocol was registered in the International Prospective Register of Systematic Reviews and conducted in adherence to PRISMA 2020 checklist. Accordingly, an electronic literature search was done to identify studies published in English language, within the time frame from January 2004 to June 2024. The search was conducted through popular databases including PubMed (Medline – National Library of Medicine), Scopus (Science Direct), EMBASE and Google Scholar following the inclusion and exclusion criteria answering the research question in focus. After thorough scrutiny, 15 studies qualified for the systematic review. Following retreatment, in all of the studies pre-treatment working length was achieved, with both the types of endodontic sealers. However, none of the micro-CT studies reported complete removal of endodontic filling material from the root canals. Irrespective of the sealer type used, within each root canal, apical third had the greatest amount of remaining filling material, followed by the middle and coronal thirds. Retreatment of canals obturated with bioceramic sealers is feasible in most cases using traditional instruments and techniques. Active irrigation and supplemental mechanical removal, which employs lasers, XP-Finisher, and ultrasonics, adds advantage to maximize material removal. [ABSTRACT FROM AUTHOR]

This study aims to compare the shaping ability of three systems using micro‐computed tomography (micro‐CT). Moderately‐curved mesial canals of 36 mandibular molars were assigned to three groups (n = 24); Protaper Next (PTN, 0.25, 0.06), WaveOne Gold (WOG, 0.25, 0.07), TruNatomy (TRN, 0.25, 0.04), and instrumentation was performed. Pre‐ and post‐micro‐CT scans were obtained. Canal volume and surface, structure model index (SMI), centroid shift, canal transportation, and untouched canal were analyzed. One‐way ANOVA and Student's t‐test were used for statistics. There was no difference in SMI, centroid shift, and centering ability between the study groups (p >.05). Removed dentin and canal surface changes were lower in TRN, while untouched dentin walls were higher (p <.05). Cross‐sections became more rounded (p <.05), but not significant between groups (p >.05). Considering the removed dentin by TRN, it can be used in critical dentin thickness, such as the danger zone (DZ). PTN, WOG, and WOG kept the original canal course similarly. Untouched dentin by TRN (41%) was wider than PTN and WOG, consequently, meticulous irrigation is recommended. TRN, which provides a controlled increase in canal volume, can be used in thin dentin such as the DZ, however, its use should be supported by copious irrigation and brushing considering the rate of untouched dentin walls. Research Highlights: TRN presented a higher untouched dentin wall compared to PTN and WOG.Canal volume and surface changes were the lowest in the TRN group.The centering abilities were similar in PTN, WOG, and TRN. [ABSTRACT FROM AUTHOR]

Objectives: Down syndrome (DS) is associated with airway abnormalities including a narrowed trachea. It is uncertain whether this narrowed trachea in DS is a consequence of deviant fetal development or an acquired disorder following endotracheal intubation after birth. This study aimed to compare the tracheal morphology in DS and non‐DS fetuses using microfocus computed tomography (micro‐CT). Methods: Twenty fetal samples were obtained from the Dutch Fetal Biobank and divided into groups based on gestational age. Micro‐CT images were processed to analyze tracheal length, volume, and cross‐sectional area (CSA). Results: Mean tracheal length and tracheal volume were similar in DS and non‐DS fetuses for all gestational age groups. Mean, minimum, and maximal tracheal CSA were statistically significantly increased in the single DS fetus in the group of 21–24 weeks of gestation, but not in other gestational age groups. In 90% of all studied fetuses, the minimum tracheal CSA was located in the middle third of the trachea. Conclusion: Tracheal development in DS fetuses was similar to non‐DS fetuses between 13 and 21 weeks of gestation. This suggests that the narrowed tracheal diameter in DS children may occur later in fetal development or results from postnatal intubation trauma. The narrowest part of the trachea is in majority of DS and non‐DS fetuses the middle third. Level of Evidence: 3 Laryngoscope, 134:4389–4395, 2024 [ABSTRACT FROM AUTHOR]

This study evaluated the changes in physicochemical properties and appearance quality of long-grain rice during the grinding process using image technologies and aimed to provide reference for future research. The brown rice milling process was divided into three stages, and flatbed scanning, scanning electron microscopy (SEM), X-ray micro-computed tomography (micro-CT), low-field nuclear magic resonance (LF-NMR), and headspace–gas chromatography–ion mobility spectrometry (HS–GC–IMS) were employed to examine the physicochemical and volatile properties of the samples. Results revealed a continuous increase in the degree of milling, with a broken rice rate and a whiteness value increasing by 50.84% and 21.13%, respectively, compared with those during the initial stage; dietary fiber and vitamin B1 contents were reduced by 54.41% and 66.67%, respectively. The image results visualized showed that the cortex of brown rice was gradually peeled off with the increase in milling degree; the cortical thickness was gradually reduced, the endosperm was gradually exposed, and the surface was smoother and shinier. T2 populations exhibited a shift toward longer relaxation times, followed by a decrease in relaxation time during the milling process. Additionally, 31 target compounds impacting rice flavor, mainly ketones, alcohols, and esters, were identified, and the concentration of volatile substances in the B region decreased with the reduction in the bran layer; the concentration of volatile substances in the C region provided rice flavor, which increased with the milling process. This study showed changes in the physicochemical properties and appearance quality of long-grain brown rice during milling. Furthermore, the use of various image processing techniques offers significant insights for optimizing processing parameters and enhancing overall quality and taste. [ABSTRACT FROM AUTHOR]

Background: The Trident II Tritanium acetabular shell is additively manufactured (3D printed), based on the established Trident 'I' Tritanium shell, produced using conventional methods; this study characterised their differences. Methods: We obtained 5 Trident I (T1) and 5 Trident II (T2) shells sized 52 mm, 54 mm (n = 3) and 60 mm. We measured their: mass, shell-liner engaging surface roughness, roundness, wall thickness, the depth of the bone-facing porous layer, porosity, and the number, volume and location of structural voids. Results: The mass varied by up to 13.44 g. The T1 and T2 shells had a median internal roughness of 0.18 μm and 0.43 μm, (p < 0.001) and the median departure from roundness was 6.9 μm and 8.9 μm, (p < 0.001). The 54 mm and 60 mm T2 shell walls were 37% and 29% thinner than their T1 counterparts (p < 0.01). The T2 shells had irregular porous structures, shallower in depth by 11–27% (p < 0.001) than T1 shells, which had repeating mesh units; the overall porosity was comparable (54%). All T2 shells had between 115 and 3415 structural voids, compared with two T1 shells containing 21 and 31 voids. There was no difference in the depth of the porous layer for the 54 mm T2 shells (p = 0.068), whilst T1 shells did show variability (p < 0.01). Both groups showed a variability in surface roughness and roundness (p < 0.01). Conclusion: This is the first study to compare shells from a single manufacturer, produced using conventional and additive methods. This data will help interpret the performance of the 3D printed Trident II as longer-term clinical data is generated. [ABSTRACT FROM AUTHOR]

The success of foam-induced flow diversion in fractured carbonates hinges on proper injection strategies, requiring an in-depth understanding of the factors responsible for stimulating fracture–matrix interactions. In this study, we present a novel investigation of the interactions between the fracture and the matrix influenced by the mobility control effect during CH4-foam injections. These interactions were probed at the pore scale using a three-phase flow system integrated with a high-resolution micro-CT scanner. In situ phase saturations were monitored and quantified to interpret the resulting fluid transport at various injection parameters. At the initial stage of foam injection, the surfactant solution was able to invade the matrix leading to water/oil displacement events, however, impeding gas penetration. Increasing total injection velocity produced higher in situ foam quality in the fracture than the injected quality, where significant fraction of the surfactant solution from the foam was primarily diverted into the matrix. A pronounced increase in the average gas saturation within the matrix was only observed at the highest injection velocity. The pore-scale evidence showed the occurrence of combined displacement processes (water/oil, gas/oil, gas/oil/water) in the matrix, attributed to the established mobility control in the fracture, which contributed to the diversion of surfactant solution and gas to the matrix. Lastly, the injection–soaking–production technique effectively mobilized the residual oil after a long injection process of CH4-foam. At this stage, the surfactant solution was no longer playing a role as the primary invading fluid; rather, it was the diverted gas that led to the increase in the matrix-oil production. [ABSTRACT FROM AUTHOR]

As the number of FCEV vehicles increases, the importance of safe hydrogen fuel storage becomes larger. Hydrogen energy needs a high-pressure composite pressure vessel called a type 4 fuel tank. The type 4 fuel tank consists of a plastic liner and filament winding of composite fibers. During use, the hydrogen fuel tank is repeatedly charged and discharged, which causes damage to the composite region of the fuel tank. Therefore, to ensure the safe use of hydrogen fuel, it is necessary to monitor the condition of the hydrogen fuel tank. This article proposes a new, practical structural health monitoring (SHM) method based on the correlation between ultrasonic attenuation and crack density. The propagating ultrasonic wave attenuates by interaction with the damages in the composite materials of the fuel tank. Hydraulic cycle tests were performed to reproduce repeated damages in the fuel tanks. The micro-CT imaging method was used to verify the actual crack density of the fuel tank. The attenuation of the ultrasonic wave propagation and the crack density of fuel tanks were combined in one equation using the hydraulic test cycle as a parameter. With this practical SHM method, real-time structural health monitoring of type 4 fuel tanks can be done by measuring ultrasonic wave propagation on the fuel tank with the PZT active sensor network, offering hope for improved safety in the automotive and aerospace industries. [ABSTRACT FROM AUTHOR]

Synchrotron radiation propagation-based phase-contrast micro-computed tomography (SRμCT) has been used increasingly for detailed characterization of tissue specimens, alternative to classical histology. It allows rapid and nondestructive three-dimensional (3D) virtual histology of unstained specimens. Although many studies show that standard protocols for formalin-fixation and paraffin-embedded (FFPE) tissue specimens are well suited for propagation based phase-contrast imaging (PBI), refinement of sample preparation protocols for this relatively recent development is still in its early stage. There are several limitations using FFPE blocks including air-bubble inclusion, and crack formation, which affect the quality of the micro-CT scans. In this study we demonstrate that optical clearing of colon cancer specimen followed by embedding in Phytagel, as an alternative sample preparation protocol yields comparable PBI micro-CT image quality and mitigates the aforementioned drawbacks of FFPE specimens. Moreover, since single-distance phase retrieval algorithms for PBI image reconstruction expect scanned materials to be either weakly-absorbing or having a fixed ratio between absorption and phase shift, we hypothesize that optical clearing will result in specimens that are well in line with these mathematical assumption of the applied phase retrieval algorithm (homogeneous form of the Transport-of-Intensity equation TIE-HOM). In addition, we show that classical histological analysis is still possible after re-embedding of the specimen in paraffin. Thus, the proposed novel workflow to scan optical cleared specimens using SRμCT can be used in combination with light sheet microscopy and can be integrated in a classical pipeline for pathological tissue characterization. [ABSTRACT FROM AUTHOR]

Objective To investigate whether there are differences in the bone mass and microstructure of the lumbar vertebrae in different regions of osteoporosis rats induced by ovariectomy (OVX) based on micro-CT. Methods Thirty female SD rats were randomly divided into basic group, Sham group, and OVX group. The 5th lumbar vertebrae were taken on the day of surgery, 3 months (3M) after surgery, and 6 months (6M) after surgery. Micro-CT was used to analyze the bone mass and microstructure changes in the distal, middle, proximal, and whole regions. Results ①Dynamic changes in bone microstructure of rats in each group: BMD and BV/TV in all regions (except for the 3M proximal region) of Sham group rats increased significantly over time (P<0.01, P<0.05), Tb.Th in the distal, proximal, and whole regions increased significantly over time (P<0.01), and Tb.N in the middle region increased significantly (P<0.05). In OVX rats at 3M and 6M, BMD and BV/TV significantly decreased over time in all regions (except for the 3M proximal region, P<0.01, P<0.05). Rats of OVX 3M showed a significant decrease in Tb.N in all regions compared to those in the basic group (P<0.01, P<0.05). Tb.SP in the distal, middle, and whole regions increased significantly (P<0.01, P<0.05). Rats of OVX 6M showed a significant decrease in Tb.Th in the middle region, compared to those in the basic group (P<0.05), a significant decrease in Tb.N in each region (P<0.01), and a significant increase in Tb.Sp (P<0.01, P<0.05). ②Sensitivity analysis of bone microstructure changes in OVX rats: In rats of OVX 3M, except for the proximal region, BMD and BV/TV in the other three regions reduced significantly compared to those in the Sham group (P<0.01). Tb.Th of OVX rats in the distal and whole regions reduced significantly compared to those in the Sham group (P<0.05). Tb.N of OVX rats in the distal, middle, and whole regions reduced significantly (P<0.01) and Tb.Sp significantly increased (P<0.01, P<0.05). In rats of OVX 6M, BMD and BV/TV in all regions reduced significantly compared to those in the Sham group (P<0.01). Tb.Th and Tb.N in OVX rats in all four regions reduced significantly compared to those in the Sham group (P<0.05, P<0.01). Tb.Sp increased significantly (P<0.01). Conclusion At different stages of osteoporosis, the trend of bone mass and bone microstructure changes is the same in different regions, but the sensitivity of each indicator change is different. In the later stages of osteoporosis, each region can be set as the analysis area. However, in the early stage, it is more appropriate to choose the distal region or the overall region. Considering factors such as the difficulty of analyzing operational methods, it is recommended to choose the distal region as the analysis area for osteoporosis rats induced by OVX. [ABSTRACT FROM AUTHOR]

3D printing technology allows for precise control of preparing complex geometries and internal defects in printed rock analogs, while in-situ Micro-CT imaging enables real-time observation of crack behavior. The combination of these technologies offers a new research approach for studying rock crack behavior. In this study, 3D-printed rock-like specimens containing a pre-existing flaw were prepared using a gypsum powder-based 3D printer. An advanced in-situ Micro-CT system equipped with a loading device was used to quantitatively and visually investigate the crack behavior in 3D-printed specimens under uniaxial compression testing. 2D CT images obtained from in-situ compression testing at different deformations could be used to reconstruct a 3D model and visually identify the crack patterns of the extracted cracks in 3D-printed specimens. The initiation angle of cracks, volume of the pre-existing flaw, volume of newly formed cracks, and damage value with respect to strains were analyzed to quantitatively investigate crack behavior. The results indicated that within the 3D-printed specimens, tensile cracks were first initiated near the internal flaw, followed by the occurrence of shear cracks or tensile-shear mixed cracks at the flaw tips. Additionally, there was a negative linear correlation between the initiation angle of newly formed cracks and the initial flaw angle. For flaw angles in the range of 0° ≤ α ≤ 45°, a higher number of newly formed cracks were observed in the 3D-printed specimens, and the rates of increase in crack volume and damage values with strain were faster. However, for flaw angles in the range of 45° < α ≤ 90°, the results showed the opposite trend. Furthermore, through comparison with the crack behavior of natural rocks containing a single flaw, it was found that the failure modes and crack behavior of the 3D-printed specimens exhibit certain similarities with natural rocks. Highlights: In-situ Micro-CT tests were performed on 3D-printed specimens with a single flaw during uniaxial compression. Crack behavior in 3D-printed rock-like specimens during uniaxial compression were visually and quantitatively investigated. Damage evolution of the initial flaw and newly formed cracks in 3D-printed rock-like specimens were respectively discussed. Comparison of crack behavior between 3D-printed specimens and natural rocks were investigated. [ABSTRACT FROM AUTHOR]

This article explores the challenges of diagnosing rickets and scurvy in human skeletal remains. The authors suggest a temporary pause on using microscopic mineralization defects to diagnose rickets, as more data is needed for certainty. They propose using terms like "highly consistent/typical" and "consistent with" instead. The article also discusses the potential use of machine learning and artificial intelligence in evaluating mineralization defects in bones and teeth. It emphasizes the prevalence of rickets and vitamin D deficiency globally and highlights the need for further research and collaboration between paleopathologists and clinicians. The article concludes by emphasizing the importance of interdisciplinary research in addressing global health issues. [Extracted from the article]

Study Design. Experimental porcine anterior cervical discectomy and fusion (ACDF) model: a proof-of-concept study. Objective. The effect of monetite synthetic bone graft (SBG) containing calcium pyrophosphate and ß-tricalcium phosphate on cervical spinal fusion in a noninstrumented two-level large animal model. Summary of Background Data. ACDF is the gold standard surgical technique for the treatment of degenerative cervical spinal diseases. However, pseudarthrosis associated with increased patient morbidity occurs in ~2.6% of the surgeries. SBG may enhance bony fusion and subsequently decrease the risk of pseudarthrosis. Recent studies on monetite-based SBGs for use in large cranial defects in humans have shown promising bone healing results, necessitating further investigation of their use in cervical spinal fusion. Materials and Methods. Four adult female Danish Göttingen minipigs received partial cervical anterior discectomy and intervertebral defects at an upper and lower level. One defect was filled with SBG, and the other was left empty. Bony fusion was evaluated using computed tomography (CT) at three-month intervals for 12 months. Fifteen months postsurgery, the animals were euthanized for further ex vivo qualitative histopathologic and micro-CT evaluations. Fusion rates were compared using the Fisher exact test at each time point. Results. Increased interbody bony fusion rates were observed at SBG levels (4/4) compared with control levels (0/4) evaluated by CT at 6 and 9 months postsurgery (P=0.029). Fusion was observed at all SBG levels 12 months postsurgery and at only one control level. Histopathologic evaluation confirmed high-quality interbody bony fusion at all SBG levels and fusion by spondylosis at one control level. Conclusion. This proof-of-concept study provides preliminary evidence of a novel, calcium pyrophosphate-containing, and ß-tricalcium phosphate-containing monetite SBG that promotes bony fusion compared with a negative control in a clinically relevant porcine model of ACDF. [ABSTRACT FROM AUTHOR]

Background: Visualizing (micro)vascular structures remains challenging for researchers and clinicians due to limitations in traditional radiological imaging methods. Exploring the role of vascular development in craniofacial malformations in experimental settings can enhance understanding of these processes, with the effectiveness of high-resolution imaging techniques being crucial for successful research in this field. Micro-CT imaging offers 3D microstructural insights, but requires contrast-enhancing staining agents (CESAs) for visualizing (micro)-vascular tissues, known as contrast-enhanced micro-CT (CECT). As effective contrast agents are crucial for optimal visualization, this review focuses on comparative studies investigating such agents for micro-vascular tissue imaging using micro-CT. Furthermore, we demonstrate the utilization of B-Lugol solution as a promising contrast agent for acquiring high-quality micro-CT images of (micro)vascular structures in human embryonic samples. Method: This scoping review followed Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols. PubMed database provided relevant articles, screened initially by title and abstract. Inclusion and exclusion criteria defined outcomes of interest. Results: From an initial search, 273 records were identified, narrowed down to 9 articles after applying our criteria. Additionally, two articles were added through citation searching. This, a total of 11 articles were incorporated in this study. Conclusion: This micro-CT contrast agent review underscores the need for tailored choices based on research goals. Both Barium sulfate and Iodine-based agents showing excellent results, providing high resolution (micro) vascular content, especially in ex-vivo specimens. However, careful consideration of protocols and tissue characteristics remains imperative for optimizing the effectiveness of micro-CT imaging for the study of cranio-facial vascular development. [ABSTRACT FROM AUTHOR]

Background and Objectives: Curettage is the removal of a tumor from the bone while preserving the surrounding healthy cortical bone, and is associated with higher rates of local recurrence. To lower these rates, curettage should be combined with local adjuvants, although their use is associated with damage to nearby healthy bone. Objective: The purpose of this analysis is to determine the effect of local adjuvants on cortical porcine bone by using micro-computed tomography (micro-CT) along with histological and mechanical examination. Methods: Local adjuvants were applied to porcine specimens under defined conditions. To assess changes in bone mineral density (BMD), a micro-CT scan was used. The pixel gray values of the volume of interest (VOI) were evaluated per specimen and converted to BMD values. The Vickers hardness test was employed to assess bone hardness (HV). The depth of necrosis was measured histologically using hematoxylin and eosin-stained tissue sections. Results: A noticeable change in BMD was observed on the argon beam coagulation (ABC) sample. Comparable hardness values were measured on samples following electrocautery and ABC, and lowering of bone hardness was obtained in the case of liquid nitrogen. Extensive induced depth of necrosis was registered in the specimen treated with liquid nitrogen. Conclusion: This study determined the effect of local adjuvants on cortical bone by using micro-CT along with histological and mechanical examination. Phenolization and liquid nitrogen application caused a decrease in bone hardness. The bone density was affected in the range of single-digit percentage values. Liquid nitrogen induced extensive depth of necrosis with a wide variance of values. [ABSTRACT FROM AUTHOR]

Abstract Over the past decade, there has been growing interest in the sedimentological community to use micro X‐ray computed tomography to analyse microfacies in sediment cores. However, little attention has been paid to the application of micro‐computed tomography in lithified deposits, even though this can allow their texture to be characterised in three dimensions, providing key information about sedimentary structures. A novel application of micro‐computed tomography in lithified sediment‐gravity flow deposits is presented with the objective of characterising their internal 3D sedimentary structures. This technique is applied to three deep‐marine sandstones showing different compositional properties: Cretaceous Gosau Group (Austria), Eocene Hecho Group (Spain) and the Oligocene Annot Formation (France). From micro‐computed tomography data the size of particles and their distribution throughout the sample is reconstructed in 3D permitting a better visualisation of sedimentary textures. Particle distributions computed from micro‐computed tomography are similar to those computed from thin section image analysis, corroborating the reliability of the micro‐computed tomography to evaluate grain‐size trends. Micro‐computed tomography is complemented with micro‐X‐ray fluorescence and thin section petrographic analyses. In cases where mineral composition or grain size are homogeneous or matrix and grains have similar mineral composition, sedimentary structures do not appear visible from micro‐X‐ray fluorescence or thin section analyses. By separating particles based on their computed tomography density, it is possible to isolate the coarsest fraction, highlighting the sedimentary structures. This study demonstrates (i) the potential of micro‐computed tomography in analyses of sedimentary structures from outcrop data and (ii) the importance of the mineralogical composition and degree of grain sorting in assessing the origin of structureless deposits. Considering the importance of visualising sedimentary structures when interpreting depositional processes, micro‐computed tomography is a new and reliable tool to assess the physical properties of sandstones and to analyse their internal 3D sedimentary structures.

Erik Briffault,1,2 Ricardo Reyes,2,3 Patricia Garcia-Garcia,1,2 Helena Rouco,1 Luis Diaz-Gomez,4 Maria Rosa Arnau,2,5 Carmen Evora,1,3 Patricia Diaz-Rodriguez,2,4 Araceli Delgado1,2 1Department of Chemical Engineering and Pharmaceutical Technology, Universidad de La Laguna, La Laguna, 38206, Spain; 2Institute of Biomedical Technologies (ITB), Universidad de La Laguna, La Laguna, 38320, Spain; 3Department of Biochemistry, Microbiology, Cell Biology and Genetics, Universidad de La Laguna, La Laguna, 38200, Spain; 4Department of Pharmacology, Pharmacy and Pharmaceutical Technology, I+D Farma Group (GI-1645), Facultad de Farmacia, Instituto de Materiales (iMATUS) and Health Research Institute of Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, Santiago de Compostela, 15782, Spain; 5Servicio de Estabulario, Universidad de La Laguna, La Laguna, 38206, SpainCorrespondence: Patricia Diaz-Rodriguez; Araceli Delgado, Email patricia.diaz.rodriguez@usc.es; adelgado@ull.edu.esIntroduction: Osteoporosis is a metabolic disorder characterized by the loss of bone mass and density. Nucleic acid-based therapies are among the most innovative approaches for osteoporosis management, although their effective delivery to bone tissue remains a challenge. In this work, SFRP1-silencing GampeR loaded-nanoparticles were prepared and functionalized with specific moieties to improve bone targeting and, consequently, therapeutic efficacy. SFRP1-silencing would promote osteoblastic differentiation by enhancing the WNT/β-catenin pathway and thus diminishing the progression of osteoporosis.Methods: A nucleic acid-based delivery system consisting of lipid-polymer hybrid nanoparticles (LPNPs) loading a GapmeR for SFRP1 silencing was developed and further functionalized with two bone-targeting moieties: a specific aptamer (Apt) for murine mesenchymal stem cells and an antiresorptive drug, namely alendronate (ALD). These systems were tested in vivo in osteoporotic mice at different dosage regimens to analyze dose dependence in bone-forming activity and potential toxicity. The quality of trabecular and cortical bone was assessed by both micro computed tomography (micro-CT) and histological and histomorphometric analyses. Early and late osteogenesis were quantified by immunohistochemistry.Results: Results showed that functionalizing LPNPs loaded with an SFRP1-silencing GapmeR using both Apt and ALD improved bone quality and enhanced osteogenesis following a dose–effect relationship, as revealed by micro-CT, histological and immunohistochemical analyses. In contrast, non-functionalized LPNPs did not produce these effects.Conclusion: These findings highlight the relevance of proper targeting and dosage in nucleic acid-based therapeutics, proving to be crucial for exerting their therapeutic effect: a deficient targeting strategy and/or dosage may result in the therapeutic failure of an adequate gene therapy agent. Keywords: osteoporosis, bone targeting, nanoparticle dose-effect, gene therapy, aptamer, alendronate, micro-CT

Abstract Background Adult growth hormone deficiency (AGHD) is associated with an increased risk of fractures and impaired bone microstructure. Understanding the metabolic changes accompanying bone deterioration in AGHD might provide insights into mechanisms behind molecular changes and develop new biomarkers or nutritional strategies for bone destruction. Our study aimed to investigate the association between altered metabolite patterns and impaired bone microstructure in adult rats with growth hormone deficiency. Methods Thirty seven-week-aged adult Lewis dwarf homozygous (dw/dw) rats (five females and five males), and adult Lewis dwarf heterozygous (dw/ +) rats (five females and five males) rats were compared. Micro-computed tomography (Micro-CT) was used to examine the bone's microstructure. Hematoxylin and eosin (H&E) staining were used to quantify the histological characteristics. Liquid chromatography-mass spectrometry untargeted serum metabolomic analysis was applied in the study. ELISA was used to measure serum bone turnover markers and IGF-1 levels. Results Adult dw/dw rats exhibited great reductions in trabecular volume bone density (Tb.vBMD), bone volume/total volume (BV/TV), and cortical thickness (Ct. Th) compared with adult dw/ + rats (all p values

Abstract Traditional approaches to the human cochlear nerve have been impeded by its bony encasement deep inside the skull base. We present an innovative, minimally invasive, therapeutic pathway for direct access to the nerve to deliver novel regenerative therapies. Neuroanatomical studies on 10 cadaveric human temporal bones were undertaken to identify a potentially safe therapeutic pathway to the cochlear nerve. Simulations based on three-dimensional delineation of anatomical structures obtained from synchrotron phase-contrast imaging were analyzed. This enabled the identification of an approach to the nerve in the fundus of the internal auditory meatus by trephining the medial modiolar wall of the cochlea via the round window for a median depth of 1.48 mm (range 1.21–1.91 mm). The anatomical access was validated on 9 additional human temporal bones using radio-opaque markers and contrast injection with micro-computed tomography surveillance. We thus created an effective conduit for the delivery of therapeutic agents to the cochlear nerve.

The influences of biological, chemical, and flow processes on soil structure through microbially induced carbonate precipitation (MICP) are not yet fully understood. In this study, we use a multi-level thresholding segmentation algorithm, genetic algorithm (GA) enhanced Kapur entropy (KE) (GAE-KE), to accomplish quantitative characterization of sandy soil structure altered by MICP cementation. A sandy soil sample was treated using MICP method and scanned by the synchrotron radiation (SR) micro-CT with a resolution of 6.5 μm. After validation, tri-level thresholding segmentation using GAE-KE successfully separated the precipitated calcium carbonate crystals from sand particles and pores. The spatial distributions of porosity, pore structure parameters, and flow characteristics were calculated for quantitative characterization. The results offer pore-scale insights into the MICP treatment effect, and the quantitative understanding confirms the feasibility of the GAE-KE multi-level thresholding segmentation algorithm.

Abstract We developed a novel clamping device for laparoscopic surgery, free from conventional pinch structure, capable of uniformly occluding any ductal organ. This study aimed to evaluate performance of the new clamper compared to the pinch-type clamper. The new clamper consists of two metal bars with ties at each end, which enables parallel clamping. A resected porcine stomach was used, with an infusion tube at the anal end to increase intra-luminal pressure. The oral side of the stomach was clamped with either the new clamper or the pinch-type clamper, and their performances were evaluated in qualitative and semi-quantitative manner. Qualitative evaluation involved imaging the clamping site at intra-gastric pressures from 0 to 15 mmHg using microfocus computed tomography. The new clamper showed no gap even under increased intra-luminal pressure, while the pinch-type clamper showed a gap on the distal side. Quantitative evaluation measured bursting pressure under continuous air insufflation. Air leakages were observed in the new clamper at higher intra-luminal pressures than in the pinch-type clamper (46.1 mmHg vs. 13.6 mmHg, P

Aim: To evaluate the propagation of preexisting dentinal microcracks after instrumentation with ProTaper Universal (PTU), ProTaper Gold (PTG), Twisted File Adaptive (TFA), and Reciproc Blue (RB) instruments by micro-CT imaging. Methods: The mesial roots of 60 mature human mandibular molars were cut out approximately 10 mm from the apex. The roots were then divided randomly into four groups (n = 15) based on file system used: PTU, PTG, TFA, and RB. Before and after canal shaping, roots were scanned with micro-CT. The preinstrumentation cross-sectional slices were examined to ascertain the presence of preexisting dentinal microcracks in apical 10 mm of radicular dentine. Postinstrumentation, the extension of preexisting dentinal microcracks was assessed and compared with corresponding preinstrumentation image to determine the grade of propagation. Postinstrumentation, the propagation of preexisting dentinal microcracks were categorized into three grades: nonpropagated dentinal microcracks (Grade 1), incomplete propagation (Grade 2), and complete propagation (Grade 3). Results: The PTU system showed a significantly higher propagation of preexisting dentinal microcracks compared to PTG, TFA, and RB system (P ≤ 0.05). All the instrumentation systems showed propagation of preexisting dentinal microcracks into Grade 2 cracks. Grade 3 propagation was seen in PTU, PTG, and RB systems. The number of Grade 2 dentinal microcracks were significantly higher than Grade 1 dentinal microcracks for the PTU system (P ≤ 0.05). Conclusion: Root canal instrumentation promotes propagation of preexisting dentinal microcracks. As compared to conventional nickel-titanium file systems, reciprocating and thermally treated file systems may less likely result in propagation of dentinal microcracks.

Abstract Background The Trident II Tritanium acetabular shell is additively manufactured (3D printed), based on the established Trident ‘I’ Tritanium shell, produced using conventional methods; this study characterised their differences. Methods We obtained 5 Trident I (T1) and 5 Trident II (T2) shells sized 52 mm, 54 mm (n = 3) and 60 mm. We measured their: mass, shell-liner engaging surface roughness, roundness, wall thickness, the depth of the bone-facing porous layer, porosity, and the number, volume and location of structural voids. Results The mass varied by up to 13.44 g. The T1 and T2 shells had a median internal roughness of 0.18 μm and 0.43 μm, (p

Objective To evaluate the caries excavation efficacy and minimally invasive potential of three dentine caries excavation methods including traditional excavation, chemomechanical excavation, and fluorescence-aided caries excavation using micro-computerized tomography (micro-CT). Methods This study was approved by the Biomedical Research Ethics Committee, and all patients provided informed consent. Thirty molars and premolars with dentin caries were collected and randomly divided into three groups. The samples were obtained by traditional excavation (traditional excavation group), chemomechanical excavation (chemomechanical excavation group), and fluorescence-aided caries excavation (fluorescence-aided caries excavation group), and the operation time for each sample was recorded. Micro-CT was used to scan and record the caries volume and healthy tooth volume of each tooth before and after caries excavation. The caries excavation efficacy and minimally invasive potential of the three caries excavation methods were evaluated based on the caries volume and the healthy tooth volume before and after caries excavation. Results In terms of caries excavation operation time, the chemomechanical excavation group (501.7 s ± 143.6 s) had a longer operation time than the traditional excavation group (263.9 s ± 121.2 s) and the fluorescence-aided caries excavation group (284.2 s ± 135.6 s), with a statistically significant difference (PPP

The study of insect morphology has recently benefited greatly from the emergence of new digital imaging and analysis technologies such as X-ray Micro-computed tomography (μ-CT), digital 3D reconstruction, and animation. Through interactive gaming and virtual reality, the external morphology of insects can be studied by a broad audience of both entomologists and non-specialists. EntomonVR is a serious game designed to investigate the external morphology of insects with adequate quality for the virtual reality platform. In this research, we discuss the advantages of virtual reality, introduce the EntomonVR new educational game, and conclude about future perspectives, validations, and cost-effectiveness. We tested this game on 25 participants with an entomological background for assessment and improved it based on their feedback. This study demonstrates the efficacy of virtual reality technology for an experimental learning environment in teaching the morphology of insects and the crucial need for advancing an efficient and interactive educational program.

Introduction and aims: Altering the position and orientation of the root canal access cavity passway, or modifying the reduction of dentin volume, can influence the strength of dentition. This study aimed to compare the effects of different access cavities on the biomechanical performances of maxillary central incisors with a finite element analysis. Methods: Based on the micro-computed tomography (CT) scan of a maxillary central incisor, the finite element models of the intact tooth and teeth with 4 access cavity designs: conservative incisal access cavity, incisal access cavity, conservative access cavity, and traditional access cavity were generated. Simulated occlusal forces were applied at the incisal edge of the incisor in the finite element analysis procedure. Results: The maximum von Mises stress and maximum principal stress in the cervical area are highest in the traditional access cavity group, followed by the conservative access cavity group, incisal access cavity group, and conservative incisal access cavity group. Conclusion: The conservative access cavities minimise the extent of dentin removal from the cervical region, protecting the mechanical behaviour of the incisor. Moving the access cavity entry point to the incisal edge also improves the fracture resistance of the incisor. Clinical Relevance: This study's findings would help clinicians select the most appropriate endodontics access cavity method when performing the root canal on maxillary central incisors.

Tay-Sachs Disease is a rare lysosomal storage disorder caused by mutations in the HEXA gene, responsible for the degradation of ganglioside GM2. In addition to progressive neurodegeneration, Tay-Sachs patients display bone anomalies, including kyphosis. Tay-Sachs disease mouse model (Hexa-/-Neu3-/-) shows both neuropathological and clinical abnormalities of the infantile-onset disease phenotype. In this study, we investigated the effects of GM2 accumulation on bone remodeling activity. Here, we evaluated the bone phenotype of 5-month-old Hexa-/-Neu3-/- mice with age-matched control groups using gene expression analysis, bone plasma biomarker analysis, and micro-computed tomography. We demonstrated lower plasma alkaline phosphatase activity and calcium levels with increased tartrate-resistant acid phosphatase levels, indicating reduced bone remodeling activity in mice. Consistently, gene expression analysis confirmed osteoblast reduction and osteoclast induction in the femur of mice. Micro-computed tomography and analysis show reduced trabecular bone volume, mineral density, number, and thickness in Hexa-/-Neu3-/- mice. In conclusion, we demonstrated that abnormal GM2 ganglioside accumulation significantly triggers skeletal abnormality in Tay-Sachs mice. We suggest that further investigation of the molecular basis of bone structure anomalies is necessary to elucidate new therapeutic targets that prevent the progression of bone symptoms and improve the life standards of Tay-Sachs patients. Key messages: We detected the markers of bone loss-associated disorders such as osteopenia and osteoporosis in the Tay-Sachs disease mice model Hexa-/-Neu3-/-. We also demonstrated for the first time there is an increase in trabecular spacing and a reduction in trabecular thickness and number indicating skeletal abnormalities in mice model using micro-CT analysis. [ABSTRACT FROM AUTHOR]