Search Results (124)

Some Cretaceous ants belonging to the stem group of Formicidae exhibit bizarre morphology. This wide range of unusual adaptive features is primarily related to the mouthparts and clypeus. The researchers were perplexed by their specific ecology, as modern ant lineages do not exhibit anything similar. Here, we report and describe a new genus based on an extraordinary and mysterious alate ant from Late Eocene Baltic amber. Undoubtedly, the new ant is classified within the subfamily Formicinae (one of the crown groups), yet it displays a highly specialised morphology and an unusual array of features that are not observed in any extant ant lineages. Neither recent nor extinct ants have such a combination of features. While the exact phylogenetic placement of the new ant remains uncertain, we offer a discussion of its potential affinities based on our constrained phylogenetic analyses. We propose that †Eridanomyrma gen. n. should be considered in the new tribe †Eridanomyrmini trib. n. This new taxon highlights the adaptive diversity of a highly specialised, extinct lineage of Eocene crown-group ants. We also present a 3D model based on X-ray computed microtomography (µCT). Full article

Objectives: This study aimed to evaluate the accuracy of CBCT-based volumetric measurements of maxillary defects and to investigate the effects of different CBCT devices, kVp settings, and segmentation software on measurement accuracy. Methods: CBCT images from eight patients with maxillary defects were used to generate 3D-printed models for volumetric assessment. Two CBCT systems (Largev Smart and Planmeca Promax) were evaluated at three different kVp settings. Volume calculations were conducted using ITK-SNAP version 4.2.2 and 3D Doctor version 4.0 software, while micro-CT served as the gold standard (GS) for comparison. Statistical analysis included a three-way ANOVA to assess the effect of CBCT parameters and software on volumetric accuracy. Additionally, post-hoc Tukey HSD analysis was performed to identify specific differences between kVp groups, and Pearson correlation analysis was used to evaluate consistency with the GS. Significance level was set at p < 0.05. Results: Higher kVp settings significantly improved volumetric accuracy, with 100 kVp yielding the smallest deviations (−3.77%) from the GS. Tukey HSD analysis revealed significant differences between 60–80 kVp (p = 0.008), 60–100 kVp (p < 0.001), and 80–100 kVp (p = 0.041), confirming the influence of kVp on accuracy. No significant differences were observed between CBCT devices or software programs (p > 0.05). A strong positive correlation (r = 0.96) between CBCT-derived and micro-CT volumes confirmed CBCT’s reliability for volumetric assessments (p < 0.001). Conclusions: CBCT provides accurate volumetric measurements of maxillary defects, particularly at higher kVp settings. These findings support its clinical application for preoperative planning and postoperative evaluation, offering a cost-effective alternative to micro-CT. Full article

Background/Objectives: Evaluation of artifact expression in CBCT images caused by different intracanal medications (IMs) considering variations in scanning and reconstruction protocols. Reconstruction protocols refer to the specific parameters and image processing techniques applied during CBCT acquisition, including voxel size, slice thickness, and artifact reduction settings. MicroCT was used as the reference standard. Methods: Root canal preparation (45./05) of upper canines was performed, and the teeth were divided into four groups (n = 10) according to the IM used: G1: Ultracal XS (UC); G2: Bio-C Temp (BCT); G3: Metapex (MT); and G4: Metapaste (MP). The specimens were sealed with temporary provisional material and stored at 37 °C and 100% humidity for 7 days. Then, they were scanned using microCT (SkyScan 1174) and two CBCTs in high and low resolutions: EagleX3D and OP300. Image registration was performed using FIJI ImageJ software (v. 1.54k). Axial, sagittal, and coronal reconstructions were quali-quantitatively evaluated by two calibrated examiners following the scores for the artifacts (dark streaks, hypodense areas, and distortion): definitely absent; probably absent; not sure; probably present and definitely present; and the possibility of using the images for endodontic diagnosis: No/Yes. Statistical analysis was performed using Fleiss’ kappa test and two-way ANOVA (α = 95%). Results: CBCT images showed greater volume distortion of intracanal medication (p < 0.05) compared to microCT images. X3D CBCT showed the highest values of distortion, regardless of resolution, compared to OP300 (p < 0.05). The highest and lowest volume distortion for intracanal medications was observed in the UC and BCT groups, respectively (p < 0.05). Conclusions: Intracanal medication generates metallic artifact expression in CBCT images, hampering endodontic diagnosis. Full article

This study presents a multi-analytical investigation of the wooden components from Khufu’s Second Solar Boat, one of the valuable archaeological discoveries in ancient Egypt. The research integrates advanced imaging and analytical techniques to identify wood species, assess deterioration patterns, and characterize the fungal and bacterial biodeteriogens. The initial visual examination documented the state of preservation at the time of discovery. Subsequently, the identification of the wood species was carried out. The deterioration status was assessed using a variety of tools, including scanning electron microscopy (SEM) and high-resolution synchrotron radiation computed microtomography (SR-μCT) for morphological alterations, X-ray diffraction (XRD) for crystallinity changes and Fourier-transform infrared spectroscopy (FTIR) to assess chemical degradation indexes of wood. Moreover, molecular techniques were used to identify and characterize the presence of biodeterioration agents. Results indicate that ancient craftsmen used cedar wood for the boat construction. The analysed samples exhibited advanced biotic and abiotic degradation, as evidenced by microbiological assessments, XRD measurements of cellulose crystallinity, FTIR indices, SEM micrographs and SR-μCT data. These results provide crucial insights into the long-term degradation processes of archaeological wood in arid environments, enhancing our understanding of ancient Egyptian woodworking practices and informing future conservation strategies for similar artifacts. Full article

This work investigates the fabrication of Ti6Al4V composites manufactured by powder metallurgy through pressureless infiltration. Porous Ti6Al4V alloy compacts with different particle sizes were fabricated by sintering and then, liquid Ag was infiltrated to obtain composites. Computed microtomography was used to analyze the samples before and after infiltration. Numerical flow simulations and dilatometry tests evaluated the kinetics of Ag infiltration into porous Ti6Al4V compacts. Microstructure was observed by SEM and mechanical strength was evaluated by compression tests. Results showed that the pore properties play a crucial role in the infiltration timing and the distribution of the Ag’s liquid. In particular, large pores allowed the infiltration to start a few °C degrees earlier than samples with smaller pores. Three-dimensional images after infiltration showed that most of the pores were filled and the remaining ones were isolated. The resulting microstructure was composed of Ti₂Ag, α-Ti and Ag phases, indicating that the Ag diffusion occurred. Furthermore, the mechanical strength depends on the interparticle neck sizes and the Ag improves the plastic deformation reached during compression tests. The best results were obtained for the samples with larger pore sizes because the resulting mechanical properties (E = 23 GPa and σ_y = 403 MPa) are close to that of human bones, making it the best candidate as an antibacterial material for biomedical use. Full article

In many soil processes, including solute and gas dynamics, the architecture of intra-aggregate pores is a crucial component. Soil management practices and wetting-drying (W-D) cycles, the latter having a significant impact on pore aggregation, are two key factors that shape pore structure. This study examines the effects of W-D cycles on the architecture of intra-aggregate pores under three different soil management systems: no-tillage (NT), minimum tillage (MT), and conventional tillage (CT). The soil samples were subjected to 0 and 12 W-D cycles, and the resulting pore structures were scanned using X-ray micro-computed tomography, generating reconstructed 3D volumetric data. The data analyses were conducted in terms of multifractal spectra, normalized Shannon entropy, lacunarity, porosity, anisotropy, connectivity, and tortuosity. The multifractal parameters of capacity, correlation, and information dimensions showed mean values of approximately 2.77, 2.75, and 2.75 when considering the different management practices and W-D cycles; 3D lacunarity decreased mainly for the smallest boxes between 0 and 12 W-D cycles for CT and NT, with the opposite behavior for MT. The normalized 3D Shannon entropy showed differences of less than 2% before and after the W-D cycles for MT and NT, with differences of 5% for CT. The imaged porosity showed reductions of approximately 50% after 12 W-D cycles for CT and NT. Generally, the largest pores (>0.1 mm³) contributed the most to porosity for all management practices before and after W-D cycles. Anisotropy increased by 9% and 2% for MT and CT after the cycles and decreased by 23% for NT. Pore connectivity showed a downward trend after 12 W-D cycles for CT and NT. Regarding the pore shape, the greatest contribution to porosity and number of pores was due to triaxial-shaped pores for both 0 and 12 W-D cycles for all management practices. The results demonstrate that, within the resolution limits of the microtomography analysis, pore architecture remained resilient to changes, despite some observable trends in specific parameters. Full article

The prototype of a biomimetic multi-spiked connecting scaffold (MSC-Scaffold) represents an essential innovation in the fixation in subchondral trabecular bone of components for a new generation of entirely cementless hip resurfacing arthroplasty (RA) endoprostheses. In designing such a functional biomaterial scaffold, identifying the microstructural and mechanical properties of the host bone compromised by degenerative disease is crucial for proper post-operative functioning and long-term maintenance of the endoprosthesis components. This study aimed to explore, depending on the occurrence of obesity, changes in the microstructure and mechanical properties of the subchondral trabecular bone in femoral heads of osteoarthritis (OA) patients caused by the MSC-Scaffold embedding. Computed microtomography (micro-CT) scanning of femoral heads from OA patients was conducted before and after the mechanical embedding of the MSC-Scaffold. Bone morphometric parameters such as bone volume/total volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) for regions surrounding the MSC-Scaffold were computed, and the mechanical properties such as bone density (ρ_B), bone compressive strength (S), and the Young’s modulus (E) within these regions were calculated. A statistically significant increase in BV/TV (by 15.0% and 24.9%) and Tb.Th (by 13.1% and 42.5%) and a decrease in Tb.N (by 15.2% and 23.6%) were observed, which translates to an increase in ρ_B (by 15.0% and 24.9%), S (by 28.8% and 49.5%), and E (by 18.0% and 29.8%) in non-obese patients and obese patients, respectively. These changes in properties are favorable for the mechanical loads’ transfer from the artificial joint surface via the MSC-Scaffold to the periarticular trabecular bone of the OA femoral head in the postoperative period. Full article

The morphology of an individual particulate refers to its shape characteristics and size properties, which both play important roles for granular matter in physics, mechanics, chemistry, and biology. In this study, ellipsoidality is defined as a 3D shape index for evaluating particle roundness, and an explicit calculation method is applied. The dependences of 3D shape characteristics (aspect ratios, sphericity, and ellipsoidal degree) on particle size (ranges from 0.063 mm to 5.0 mm) are adequately investigated with the X-ray micro-computed microtomography (uCT) imaging for hundreds of thousands of particles of crushed and natural sands. This study focuses on comparing and evaluating the specific surface area and equivalent diameter, suggesting that particle segregation and changes in surface area may explain the strong dependence of particle shape on size. The correlation between different shape metrics was analyzed by comparing crushed sand with natural sand to provide theoretical support for material filling and mechanical behaviour. The significant differences in the microscale particle size indexes of different sands by single grading are used to provide data references for further analyses of the effect of material microscale on material properties in future discrete element particle simulations. Full article

Artifacts in computed tomography and X-ray microtomography are image distortions caused by various factors. Some can be reduced before or during the examination, while others are removed algorithmically after image acquisition. The latter group includes metallic artifacts caused by metal objects in the sample. This paper proposes a new method for eliminating metallic artifacts, applying a bone- and soft-tissue decomposition (BSTD) algorithm to microtomography raw data before the reconstruction process. We show that the decomposition algorithm can effectively remove metallic artifacts in microCT images, which increases the image contrast and allows for better visualization of regions near the metallic elements. For quantity analysis, we computed SSIM and PSNR factors, and we observed values increasing from 0.97 to 0.99 and from 40 dB to 43 dB, respectively. Full article

Estrogen deficiency is one of several contributing factors to catabolic changes in bone surrounding dental implants, impairing bone repair in defects requiring bone regeneration. Functionalizing bone substitutes is an alternative approach among various strategies to address this challenge. In this study, the aim was to evaluate the effect of functionalizing deproteinized bovine bone (Bio-Oss^®, BO) with genistein via sonication on peri-implant bone defects in ovariectomized rats. The animals were randomly distributed according to the treatment into the following four groups (n = 10): BO sonicated with genistein (BOS + GEN), BO sonicated alone (BOS), untreated BO (BO), and blood clot only (CLOT). After twenty-eight days, implant removal torque was determined, and the peri-implant bone parameters were calculated based on computed microtomography. Additionally, the gene expression of bone turnover markers was evaluated. As a main result, the functionalization with genistein increased implant removal torque and the peri-implant bone volume in the BOS + GEN group compared to both BOS and BO groups (both p < 0.05). These findings suggest that the sonification of deproteinized bovine bone functionalized with genistein improves bone repair in peri-implant bone defects in ovariectomized rats. Full article

The aim of this study was to optimize a set of technological parameters (travel speed, extruder temperature, and extrusion rate) for 3D printing with a PEEK-based composite reinforced with 30 wt.% glass fibers (GFs). For this purpose, both Taguchi and finite element methods (FEM) were utilized. The artificial neural networks (ANNs) were implemented for computer simulation of full-scale experiments. Computed tomography of the additively manufactured (AM) samples showed that the optimal 3D printing parameters were the extruder temperature of 460 °C, the travel speed of 20 mm/min, and the extrusion rate of 4 rpm (the microextruder screw rotation speed). These values correlated well with those obtained by computer simulation using the ANNs. In such cases, the homogeneous micro- and macro-structures were formed with minimal sample distortions and porosity levels within 10 vol.% of both structures. The most likely reason for porosity was the expansion of the molten polymer when it had been squeezed out from the microextruder nozzle. It was concluded that the mechanical properties of such samples can be improved both by changing the 3D printing strategy to ensure the preferential orientation of GFs along the building direction and by reducing porosity via post-printing treatment or ultrasonic compaction. Full article

The historical and cultural significance of artistic works and archaeological artifacts underscores the imperative use of non-destructive testing methods in cultural heritage objects. Analyzing pigments in artwork poses a specific analytical challenge that demands a combination of various techniques to accurately determine chemical compositions. In this context, our work focused on the multi-analytical characterization of samples derived from fragments of a Roman-era Egyptian mummy named Kherima, dating back to around 200 AD. To identify the layers and elemental composition of the pigments used in the decoration, various techniques were employed: X-ray microfluorescence (µXRF), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), high-resolution optical microscopy (OM), and X-ray computed microtomography (microCT). This multi-analytical approach facilitated the identification of the original pigments in the analyzed mummy fragments, along with insights into the materials used in the ground layer and the techniques applied in artifact manufacturing, indicating their accordance with the historical period and region to which they originally belonged. Full article

Computed tomography (CT) is one of the fundamental imaging modalities used in medicine, allowing for the acquisition of accurate cross-sectional images of internal body tissues. However, during the acquisition and reconstruction process, various artifacts can arise, and one of them is ring artifacts. These artifacts result from the inherent limitations of CT scanner components and the properties of the scanned material, such as detector defects, non-uniform distribution of radiation from the source, or the presence of metallic elements within the scanning region. The purpose of this study was to identify and reduce ring artifacts in tomographic images using image decomposition and average filtering methods. In this study, tests were conducted on the effectiveness of identifying ring artifacts using wavelet decomposition methods for images. The test was performed on a Shepp–Logan phantom with implemented artifacts of different intensity levels. The analysis was performed using different wavelet families, and linear approximation methods were used to filter the image in the identified areas. Additional filtering was performed using moving average methods and empirical mode decomposition (EMD) techniques. Image comparison methods, i.e., RMSE, SSIM and MS-SSIM, were used to evaluate performance. The results of this study showed a significant improvement in the quality of tomographic phantom images. The authors obtained more than 50% improvement in image quality with reference to the image without any filtration. The different wavelet families had different efficiencies with relation to the identification of the induction regions of ring artifacts. The Haar wavelet and Coiflet 1 showed the best performance in identifying artifact induction regions, with comparative RMSE values for these wavelets of 0.1477 for Haar and 0.1469 for Coiflet 1. The applied additional moving average filtering and EMD permitted us to improve image quality, which is confirmed by the results of the image comparison. The obtained results allow us to assess how the used methods affect the reduction in ring artifacts in phantom images with induced artifacts. Full article

Bisphosphonates are widely used for the treatment of postmenopausal osteoporosis; however, they cause several long-term side effects, necessitating the investigation of local ways to improve osseointegration in compromised bone tissue. The purpose of this study was to evaluate peri-implant bone repair using implants functionalized with zoledronic acid alone (OVX ZOL group, n = 11), zoledronic acid + teriparatide (OVX ZOL + TERI group, n = 11), and zoledronic acid + ruterpy (OVX ZOL + TERPY group, n = 11) compared to the control group (OVX CONV, n = 11). Analyses included computer-assisted microtomography, qualitative histologic analysis, and real-time PCR analysis. Histologically, all functionalized surfaces improved peri-implant repair, with the OVX ZOL + TERI group standing out. Similar results were found in computerized microtomography analysis. In real-time PCR analysis, however, the OVX ZOL and OVX ZOL + TERPY groups showed better results for bone formation, with the OVX ZOL + TERPY group standing out, while there were no statistical differences between the OVX CONV and OVX ZOL + TERI groups for the genes studied at 28 postoperative days. Nevertheless, all functionalized groups showed a reduced rate of bone resorption. In short, all surface functionalization groups outperformed the control group, with overall better results for the OVX ZOL + TERI group. Full article

Among all of the materials used in tissue engineering in order to develop bioequivalents, collagen shows to be the most promising due to its superb biocompatibility and biodegradability, thus becoming one of the most widely used materials for scaffold production. However, current imaging techniques of the cells within collagen scaffolds have several limitations, which lead to an urgent need for novel methods of visualization. In this work, we have obtained groups of collagen scaffolds and selected the contrasting agents in order to study pores and patterns of cell growth in a non-disruptive manner via X-ray computed microtomography (micro-CT). After the comparison of multiple contrast agents, a 3% aqueous phosphotungstic acid solution in distilled water was identified as the most effective amongst the media, requiring 24 h of incubation. The differences in intensity values between collagen fibers, pores, and masses of cells allow for the accurate segmentation needed for further analysis. Moreover, the presented protocol allows visualization of porous collagen scaffolds under aqueous conditions, which is crucial for the multimodal study of the native structure of samples. Full article