micro-CT Scanning Research Articles

Glass beads from a Scythian grave on the island of Khortytsia (Zaporizhzhia, Ukraine): insights into bead making through 3D imaging

AbstractFour glass beads from a Scythian burial on the island of Khortytsia (Southern Ukraine) were subjected to 3D imaging using micro-CT and photogrammetry. The aim was to reconstruct the process used to produce and decorate the beads by detecting and interpreting the traces left by the technological processes on the bead surface and in the glass body. It turned out that all the beads were obtained by winding hot glass around the mandrel. The distribution, size and shape of the bubbles in the glass matrix revealed by the micro-CT scans and the features observed during a thorough examination of the photogrammetric models allowed us to follow the movements of the bead maker during the formation of the bead body and its decoration, highlighting several details of the production processes such as the number of the superimposed layers and the direction of the rotation of the mandrel during both the formation of the body and the decoration of the bead. Some information about the tools also emerged, with particular reference to the shape of the mandrel, the possible use of a releasing agent and how tools were used to decorate the surface or to remove the beads from the mandrel. According to the archaeological classification, the beads considered here belong to three different types, that are considered chronological indicators of the fourth century BCE and are found in archaeological sites spread over an area extending for several thousand kilometers from the Black Sea coast to the Ural Mountains. This work enriches the knowledge of the micromorphology of beads found in Eastern Europe, which is rarely discussed in the scientific literature on the archaeological glass beads.

Ginsenoside Rh2 enhances immune surveillance of natural killer (NK) cells via inhibition of ERp5 in breast cancer

BackgroundOne critical component of the immune system that prevents breast cancer cells from forming distant metastasis is natural killer (NK) cells participating in immune responses to tumors. Ginsenoside Rh2 (GRh2) as one of the major active ingredients of ginseng has been employed in treatment of cancers, but the function of GRh2 in modulating the development of breast cancer remains elusive. PurposeThis study was to dissect the effect of GRh2 against breast cancer and its potential mechanisms associated with NK cells, both in vitro and in vivo. MethodsMDA-MB-231 and 4T1 cells were used to establish in situ and hematogenous mouse models. MDA-MB-231 and MCF-7 were respectively co-cultured with NK92MI cells or primary NK cells in vitro. Anti-tumor efficacy of GRh2 was verified by immunohistochemistry (IHC), Cell Counting Kit-8 (CCK8), high resolution micro-computed tomography (micro-CT) scanning of lungs and hematoxylin and eosin (H&E) staining. Lactate dehydrogenase (LDH) cytotoxicity assay, flow cytometry, in vivo depletion of NK cells, enzyme-linked immunosorbent assay (ELISA), western blot, quantitative reverse transcription polymerase chain reaction (qRT-PCR), immunofluorescence and cell transfection were performed for investigating the anti-tumor mechanisms of GRh2. Molecular docking, microscale thermophoresis (MST) and cellular thermal shift assay (CETSA) were employed to determine the binding between endoplasmic reticulum protein 5 (ERp5) and GRh2. ResultsWe demonstrated that GRh2 exerted prominent impacts on retarding the growth and metastasis of breast cancer through boosting the cytotoxic function of NK cells, as validated by the elevated release of perforin, granzyme B and interferon-γ (IFN-γ). Mechanistical studies revealed that GRh2 was capable of diminishing the expression of ERp5 and GRh2 directly bound to ERp5 in MDA-MB-231 cells as well as on a recombinant protein level. GRh2 prevented the formation of soluble MICA (sMICA) and upregulated the expression level of MICA in vivo and in vitro. Importantly, the reduced lung metastasis of breast cancer by GRh2 was almost abolished upon the depletion of NK cells. Moreover, GRh2 was able to insert into the binding pocket of ERp5 directly. ConclusionWe firstly demonstrated that GRh2 played a pivotal role in augmenting NK cell activity by virtue of modulating the NKG2D-MICA signaling axis via directly binding to ERp5, and may be further optimized to a therapeutic agent for the treatment of breast cancer.

Palm fruits from the Oligocene of west coastal Peru

Two species of palms are recognized based on new collections and re-examination of carpological remains from the Oligocene of Belen, Peru: Palmocarpon bravoi Berry emend. and P. dicellaformis (Berry) comb. nov. Reflected light investigations were supplemented by micro-CT scan imagery and physical sectioning to reveal internal structure. Both species possess cylindrical peg-like protrusions on the locule casts representing germination pores of the pyrene wall. P. bravoi fruits are unilocular and relatively elongate, 12 mm long, with sub-basal pores, while those of P. dicellaformis are trilocular and 9–12 mm long with subequatorial pores. Prior identification of the trilocular fruits as capsules of Matayba (Sapindaceae) is dismissed based on the presence of germination pores. Affinities of both species are inferred to lie with the Cocosoid palms particularly close to extant Attaleinae (P. bravoi) and Bactridinae (P. dicelliformis). The Belen fruits are the best-documented occurrence of fossil Cocoseae in South America and are evidence of the group's presence before the aridification of the Pacific coast of Peru.

Impact of increasing morphological information by micro-CT scanning on the phylogenetic placement of Darwin wasps (Hymenoptera, Ichneumonidae) in amber

The correct interpretation of fossils and their reliable taxonomic placements are fundamental for understanding the evolutionary history of biodiversity. Amber inclusions often preserve more morphological information than compression fossils, but are often partially hidden or distorted, which can impede taxonomic identification. Here, we studied four new fossil species of Darwin wasps from Baltic and Dominican amber, using micro computed tomography (micro-CT) scans and 3D reconstructions to accurately interpret and increase the availability of morphological information. We then infer their taxonomic placement in a Bayesian phylogenetic analysis by combining morphological and molecular data of extant and fossil Darwin wasps and evaluate the impact and usefulness of the additional information from micro-CT scanning. The results show that although we gained significant morphological information from micro-CT scanning, especially concerning measurements and hidden dorsal and ventral structures, this did not impact subfamily-level placement for any of the four fossils. However, micro-CT scanning improved the precision of fossil placements at the genus level, which might be key in future dating and diversification analyses. Finally, we describe the four new fossil species as Rhyssa gulliveri sp. nov. in Rhyssinae, Triclistus levii sp. nov. in Metopiinae, Firkantus freddykruegeri gen. et. sp. nov. in Pimplinae and Magnocula sarcophaga gen. et sp. nov. in Phygadeuontinae. The first two species are the first known representatives of the subfamilies Rhyssinae and Metopiinae in amber.

A new lizard-like reptile with unusual mandibular neurovasculature from the Upper Triassic of Virginia

ABSTRACT Here, we report a new small-bodied reptile taxon, Idiosaura virginiensis gen. et sp. nov., from the Upper Triassic (Carnian) Vinita Formation of the Richmond basin (Newark Supergroup) in east-central Virginia, U.S.A. The material consists of a fragmentary dentary bearing numerous tall cylindrical teeth implanted in a pleurodont fashion into spongy alveolar tissue. Micro-CT scan data reveal an unusual and complex network of interconnected neurovascular canals within the dentary with connections to the alveolar tissue and pulp cavities of the teeth. The external anatomy of the dentary is consistent with that of Triassic kuehneosaurid reptiles, suggesting affinities to that group; the results of a phylogenetic analysis were inconclusive but do not exclude kuehneosaurid relationships. Alongside the recently described Micromenodon pitti (Rhynchocephalia) and Vinitasaura lizae (Lepidosauromorpha), the new taxon adds to the relatively diverse assemblage of small-bodied reptiles known from the Tomahawk microvertebrate bonebed (USNM locality 39981). Relative tooth complexities of I. virginiensis and V. lizae were analyzed using the Orientation Patch Count Rotated method, and results suggest that the rise of lepidosauromorph ecomorphologies specializing for feeding on invertebrates occurred in Triassic communities alongside non-lepidosauromorph taxa with similar mandibulo-dental features, as in kuehneosaurs.

Effect of Curing Time and Nitrogen Generator Usage on Direct 3D-Printed Aligners Thicknesses—An In Vitro Micro-CT Study

Many variables in the production of direct 3D-printed orthodontic aligners are currently tested to obtain an efficient and safe workflow. The aim of the present study was to investigate the effect of different curing times on the final thickness of the produced aligners. In total, 35 copies of the same aligner with a set thickness of 0.5 mm were directly 3D printed using the instructions provided by the manufacturer. Seven groups (five aligners each) were created. Six groups were post-cured with a nitrogen generator for, respectively, 15 min, 20 min, 25 min, 30 min, 40 min, and 50 min. The last group was cured for 30 min without the nitrogen generator. All aligners were scanned with a micro-CT scanner. To assess local aligner thickness values, a total of 20 reference points were utilised. The comparisons among groups and locations were performed using ANOVA or the Kruskal–Wallis test. Significant differences in thickness were found at various reference points. No impact on curing time was found. No direct association was found between curing time and thicknesses, nor between nitrogen generator usage and thickness. At a 60° printing inclination and following the prescribed centrifugation process, a local thickness increase on the front teeth was observed.

Characterization of a short fiber-reinforced adhesive designed for wind turbine rotor blades

Wind turbine rotor blades are usually made of two half-shells and shear webs that are joined together by structural adhesives. The adhesive joints suffer from longitudinal strains from blade bending combined with shear strains from torsion and shear forces acting on the blade. It is thus important to provide an accurate and reliable characterization of the adhesive as a bulk material to account for cohesive failure.This work focusses on the characterization of a short fiber-reinforced adhesive used in wind turbine rotor blades under uniaxial tension, compression, and shear as well as biaxial tension-compression/shear for both static and fatigue loading. To obtain small scatter in measurement results, a specimen geometry was designed that ensures a clear maximum stress in the test section while minimizing stress concentrations in the transition between the load introduction regions and the test section. The manufacturing process was then designed in such a way that an optimum mixture of resin and hardener was obtained without the inclusion of voids. The latter was verified after manufacturing by means of micro-CT scanning for all specimens. A very extensive test campaign was then carried out in order to quantify stiffness, static strength, fatigue strength, and fatigue-related stiffness degradation. Excerpts of this test campaign are presented in this paper.

The West Tofts handaxe: A remarkably average, structurally flawed, utilitarian biface

The West Tofts handaxe is a small British Acheulean biface well known for its cortical preservation of a fossilised bivalve shell. The shell's retention, its prominent central placement, and perceptions of the tool's broader aesthetic-value have resulted in it being described as an example of early hominin aesthetic intent. When combined with its mid-to-late Pleistocene age, the handaxe plausibly has implications for our understanding of hominin cognitive evolution and the origins of Palaeolithic art. Crucial to the assignment of aesthetic intent are a series of assumptions concerning the exceptionality of the tool's design, production and use. Here, we test those assumptions. The West Tofts handaxe is revealed to be technologically and morphologically unremarkable for the British late Acheulean, was produced on a tabular flint nodule that did not require invasive (central) flake removals, and displays remarkably average flaking investment. High-resolution micro-CT scans of its internal structure reveal numerous fractures and air pockets, and at least one – potentially two – additional fossilised shells. These inclusions and flaws feasibly impacted the tool's production, potentially resulting in the shell's retention. Limited microwear traces were identified on its distal flaked edges, potentially hinting at the tool's expedient use. These and other data underline the importance of restraint when attributing aesthetic intent or ‘over-investment’ to the West Tofts handaxe. Today we may consider it a remarkable artefact worthy of elevation, but to the Acheulean individual who produced it, the West Tofts handaxe was likely an average utilitarian tool produced on a flawed but conveniently thin flint nodule.

Transition from stromatolite to thrombolite fabric: potential role for reticulopodial protists in lake microbialites of a Proterozoic ecosystem analog.

Prior observations suggest that foraminiferan protists use their reticulopodia (anastomosing pseudopodia) to alter sediment fabric by disrupting laminations of subtidal marine stromatolites, erasing the layered structures in an experimental setting. Because microbialites and foraminifera are found in non-marine settings, we hypothesized that foraminifera living in lakes could also disrupt layered microbialite fabric. With this aim and using a variety of multidisciplinary approaches, we conducted field surveys and an experiment on microbialites from Green Lake (GL; Fayetteville, New York State, United States), which has been studied as a Proterozoic ecosystem analog. The lake is meromictic and alkaline, receiving calcium sulfate-rich water in the monimolimnion; it supports a well-developed carbonate platform that provides access to living and relict microbialites. The living microbialites grow from early spring to autumn, forming a laminated mat at their surface (top ~5 mm), but a clotted or massive structure exists at depth (> ~ 1 cm). We observed a morphotype of "naked" foraminiferan-like protist in samples from GL microbialites and sediments; thus, considered the possibility of freshwater foraminiferan impact on microbialite fabric. Results of an experiment that seeded the cultured freshwater foraminifer Haplomyxa saranae onto the GL microbialite surface indicates via micro-CT scanning and anisotropy analysis that the introduced foraminifer impacted uppermost microbialite layering (n = 3 cores); those cores with an added inhibitor lacked changes in anisotropy for two of those three cores. Thus, it remains plausible that the much smaller, relatively common, native free-form reticulate protist, which we identified as Chlamydomyxa labyrinthuloides, can disrupt microbialite fabrics on sub-millimeter scales. Our observations do not exclude contributions of other possible causal factors.

Spatial correlation of 2D hard-tissue histology with 3D microCT scans through 3D printed phantoms

Hard-tissue histology—the analysis of thin two-dimensional (2D) sections—is hampered by the opaque nature of most biological specimens, especially bone. Therefore, the cutting process cannot be assigned to regions of interest. In addition, the applied cutting-grinding method is characterized by significant material loss. As a result, relevant structures might be missed or destroyed, and 3D features can hardly be evaluated. Here, we present a novel workflow, based on conventual microCT scans of the specimen prior to the cutting process, to be used for the analysis of 3D structural features and for directing the sectioning process to the regions of interest. 3D printed fiducial markers, embedded together with the specimen in resin, are utilized to retrospectively register the obtained 2D histological images into the 3D anatomical context. This not only allows to identify the cutting position, but also enables the co-registration of the cell and extracellular matrix morphological analysis to local 3D information obtained from the microCT data. We have successfully applied our new approach to assess hard-tissue specimens of different species. After matching the predicted microCT cut plane with the histology image, we validated a high accuracy of the registration process by computing quality measures namely Jaccard and Dice similarity coefficients achieving an average score of 0.90 ± 0.04 and 0.95 ± 0.02, respectively. Thus, we believe that the novel, easy to implement correlative imaging approach holds great potential for improving the reliability and diagnostic power of classical hard-tissue histology.

Evaluation of shaping ability of different glide path instruments: a micro-computed tomography study

BackgroundThis study aimed to compare the shaping ability of different instruments, TruNatomy Glider (TRN-G), WaveOne Gold Glider (WOG-G), and ProGlider (Pro-G) using micro-computed tomography (micro-CT).MethodsThe mesial canals of 27 mandibular molars with two separate mesial canals and moderate curvature were included in this study [n = 27 mesiobuccal (MB) and mesiolingual (ML) root canal]. According to the manufacturer’s instructions, the glide path was created with TRN-G, WOG-G, and Pro-G glide path instruments (n = 9 MB and ML root canal in each group). Micro-CT scanning was performed before and after preparation. Mesiodistal (MD) and buccolingual (BL) transportation and the centering ratio were measured at three levels within the canal (3, 5 and 7 mm). A three-way robust ANOVA was used to compare the parameters.ResultsTRN-G showed significantly greater transportation in the MD direction than the other instruments throughout the root canal (overall root canal) (p < 0.05). The best centering ability in the BL direction was shown by the WOG-G, regardless of level within the canal and canal distinction (MB vs. ML) (p < 0.05). There was no significant difference between groups according to the level within the canal and canal parameters (p > 0.05). Whether the root canal was MB or ML did not affect centering or transportation (p > 0.05).ConclusionsGlide path instruments can be used to shape moderately curved canals with minimal apical transportation and better centering ability. All three tested glide path files can used safely before the shaping file.

Effect of autologous lyophilized platelet‑rich fibrin on the reconstruction of osteochondral defects in rabbits.

Osteochondral defects caused by degenerative diseases of joints, traumas and inflammation are important issues in clinical practice. Different types of autologous platelet concentrate (PCs) are used in bone and cartilage regeneration. The present study aimed to investigate the effect of lyophilized platelet-rich fibrin (L-PRF) on the repair of osteochondral defects in rabbits. L-PRF was first prepared from fresh PRF (F-PRF) through freeze-drying, and histological and microstructural observations were performed to compare the characteristics of L-PRF and F-PRF. Thereafter, these bioactive scaffolds were implanted into osteochondral defects surgically created in rabbits to assess their effects on tissue repair using micro-CT scanning, histological observations and the evaluation scoring method for cartilage repair established by the International Cartilage Repair Society (ICRS). L-PRF had a histological structure similar to F-PRF. At 16 weeks after implantation surgery, full-thickness osteochondral defects with a diameter of 5 mm and a depth of 4 mm were well-filled with newly regenerated tissues, exhibiting the simultaneous regeneration of avascular articular cartilage and well-vascularized subchondral bone, as proven through macroscopic and microscopic observations in PRF-treated groups compared with that in the untreated group. The application of L-PRF and F-PRF for osteochondral defects in rabbits contributed to massive host remodeling and reconstruction of osteochondral tissues, thus offering a prospective bioactive scaffold for the simultaneous reconstruction of articular cartilage and subchondral bone tissue.

Shaping outcomes of Reciproc Blue and Rotate in roots canals with band-shaped isthmuses: micro-CT study.

This study assessed the outcome of shaping the mesial roots of mandibular first molars containing band-shaped isthmuses with an isthmus floor located at the apical third with Reciproc Blue and Rotate instruments in terms of canal transportation, canal aberrations and unprepared apical canals. Pair-matched mesial roots of mandibular first molars according to their isthmus location (distance from apical foramina) and size were constructed based on quantitative measurements (length, major and minor diameter at isthmus roof and floor) on preoperative micro-CT scanning (n = 10). The pair-matched specimens were prepared either using Reciproc Blue R25 (25.08v) or Rotate (15.04, 20.05, 25.06) instruments and then subjected to a second micro-CT scanning. Micro-CT scans were analysed to evaluate the canal transportation at the apical foramen and isthmus floor levels and the frequency of procedural errors (separated instruments, artificial canal preparation, cross shaping and unprepared apical canals). Canal transportation values were compared using Mann-Whitney U, and the distribution of procedural errors was compared with chi-square tests with a 5% significance threshold. Greater transportation values were detected in the apical foramen level compared to the isthmus floor in both groups. No significant difference was detected between Rotate and Reciproc Blue groups in terms of absolute transportation values and the incidence of procedural errors (p > .05). Preparation of mesial root canals containing a band-shaped isthmus at the apical portion with Reciproc Blue and Rotate instruments caused transportation of the original canal position at the isthmus floor and the apical foramen levels and resulted in procedural errors. This ex vivo micro-CT study using controlled pair-matched specimens showed that presence of a band-shaped isthmus complicates canal preparation procedure irrespective of the preparation systems.

Material characterization uncovers sophisticated mould-making techniques of the middle-Shang period (14th-13th BCE)

Recent archaeological excavations revealed a significant amount of bronze casting moulds and cores dated to the Middle-Shang period and demonstrated it as a vital stage in the development of casting technology in Bronze Age China. This study has analyzed fifty-three mould and eight core fragments from the Taijiasi site, dated to the Middle Shang III period, using micro-CT scanning, SEM-EDS, and p-XRD. The results show that four types of materials combined in distinct ways to form three mould types at this site. Moulds for smaller bronze vessels with band-like patterns were constructed with a sand tempered material while only pattern sections were replaced with a c. 5–10 mm layer of fine silt-rich material. In contrast, moulds for larger vessels with extensive decorative patterns have a double-layered structure, comprising a fine silt-rich internal layer and a sand-grog tempered external layer. Moulds for tools and weapons were made of unprocessed loess. Casting cores display a texture similar to sand tempered moulds. This research uncovered a nuanced material selection strategy for mould manufacturing at the site of Taijiasi and highlighted the innovations of mould-making techniques in the Middle Shang period.

Exploring a Mallorca cave flooding during the Little Ice Age using nondestructive techniques on a stalagmite: micro-CT and XRF core scanning

AbstractThis study focuses on characterizing a discontinuity within the Seán stalagmite (4.75–7.75 cm) by means of two nondestructive techniques: (1) high-resolution micro-computed tomography (micro-CT) and (2) X-ray fluorescence (XRF) core scanning (XRFCS). Micro-CT was used to study the stalagmite density, and XRFCS was applied to obtain the qualitative elemental composition and colour measurements. The new data obtained from nondestructive techniques have been combined with previously published geochemical data and fabric determinations from the same stalagmite found in Sa Balma des Quartó cave in Mallorca. The two methodologies applied in the present study have improved the characterization of the distinctive horizon. The micro-CT images identified the layer as a minor event due the high air content. The distinctive horizon is characterized by a high Ti-content, indicating the arrival of terrigenous particles. Based on those observations, together with the fact that the micrite layer appears filling the gaps between the older columnar fabric, we argue that the micrite layer may represent a major flooding event inside the cave after the year 1616 ± 23 CE and before the year 1623 ± 28 CE, which can be related to an extreme rainfall event. This hypothesis is further supported by the observed cave flooding during the autumn of 2018.

Crustacean microcoprolites from the Middle Triassic Luoping Biota, China: Evidence for primary producers in the first Modern-type marine ecosystems

Modern-type marine ecosystems became established in the Triassic following the devastation of the Permian-Triassic mass extinction. Attention has been focused on higher levels of these food chains, but the primary levels have not been established in detail. Here, we present evidence of microcoprolites from the Luoping biota (early Anisian, Middle Triassic) that lophogastrid shrimps were feeding on cyanobacteria, evidence for the primary producers and consumers in the system. Microscopic study of the microcoprolites, using SEM, EDS elemental analysis, micro-CT and FIB-SEM scanning, and Raman testing, revealed that crescent-shaped, symmetrically arranged canals indicate a possibility that these micron-sized pellets belong to the ichnospecies Palaxius isp. produced by crustaceans. Comparison of the microcoprolites, with their preserved canals, with fossilized intestines from lophogastrid shrimps confirms their source, based on similarities in ultrastructure and chemical composition. Our discovery confirms the rise of Modern-type zooplankton, represented by lophogastrids and other arthropods, replacing extinct Palaeozoic marine invertebrate taxa while the phytoplankton may still have been primitive and represented by cyanobacteria. The pyramid of energy and trophic levels of a well-preserved Middle Triassic marine biota now are more fully understood, representing an example of the full recovery of the marine ecosystem.

Diversity of filter feeding and variations in cross-flow filtration of five ram-feeding fish species

IntroductionFilter-feeding fish separate food particles from the surrounding water by cross-flow filtration in which a suspension flows parallel to a porous filter medium, thereby transporting particles along the surface.MethodsHere, we investigate cross-flow filtration in five ram-feeding fish species from two groups, Scombridae (Scomber scombrus and Rastrelliger kanagurta) and Clupeidae (Clupea harengus, Sardina pilchardus, and Engraulis encrasicolus). Using a combination of morphometrics, micro-CT scanning, video analysis, and water tunnel experiments, we give a detailed description of the gill arch system, calculate filtration parameters, observe particle movement, and identify morphological traits that induce cross-flow filtration.ResultsOur findings suggest that these ram-feeding fish species use a combination of cross-flow and dead-end filtration as the underlying filtration principle. Specifically, the particles are transported along the surface of gill rakers and denticles towards the esophagus where they accumulate before being periodically swallowed. We infer three distinct morphotypes characterized by variations in geometry, mesh size, and surface structures, which indicate variations of the general mechanism.DiscussionThe description presented in this study contributes to the development of models for investigating the influence of morphological variation on fluid flow and particle retention in filter-feeding fish and on their ecology and biomimetic application.

Daidzein alleviates osteoporosis by promoting osteogenesis and angiogenesis coupling.

Postmenopausal osteoporosis and osteoporosis-related fractures are world-wide serious public health problem. Recent studies demonstrated that inhibiting caveolin-1 leads to osteoclastogenesis suppression and protection against OVX-induced osteoporosis. This study aimed to explore the mechanism of caveolin-1 mediating bone loss and the potential therapeutic target. Thirty C57BL/6 female mice were allocated randomly into three groups: sham or bilateral ovariectomy (OVX) surgeries were performed for mice and subsequently daidzein or vehicle was administrated to animals (control, OVX + vehicle and OVX + daidzein). After 8-week administration, femurs were harvested for Micro-CT scan, histological staining including H&E, immunohistochemistry, immunofluorescence, TRAP. Bone marrow endothelial cells (BMECs) were cultured and treated with inhibitors of caveolin-1 (daidzein) or EGFR (erlotinib) and then scratch wound healing and ki67 assays were performed. In addition, cells were harvested for western blot and PCR analysis. Micro-CT showed inhibiting caveolin-1with daidzein alleviated OVX-induced osteoporosis and osteogenesis suppression. Further investigations revealed H-type vessels in cancellous bone were decreased in OVX-induced mice, which can be alleviated by daidzein. It was subsequently proved that daidzein improved migration and proliferation of BMECs hence improved H-type vessels formation through inhibiting caveolin-1, which suppressed EGFR/AKT/PI3K signaling in BMECs. This study demonstrated that daidzein alleviates OVX-induced osteoporosis by promoting H-type vessels formation in cancellous bone, which then promotes bone formation. Activating EGFR/AKT/PI3K signaling could be the critical reason.

Experimental and Numerical Investigation into the Mechanical Behavior of Composite Solid Propellants Subject to Uniaxial Tension.

To further explore the quasi-static mechanical characteristics of composite solid propellants at low strain rates, an investigation was conducted on the mechanical behavior and damage mechanisms of a four-component hydroxy-terminated polybutadiene (HTPB) propellant by means of experiments and numerical simulation. A uniaxial tensile test and scanning electron microscope (SEM) characterization experiment were carried out. A microstructural model, which accurately represents the mesoscopic structure, was developed via the integration of micro-CT scanning and image-processing techniques. The constructed microstructural model was utilized to conduct a numerical simulation of the mechanical behavior. The experimental results demonstrated that the maximum tensile strength increases with increasing strain rate, and the primary cause of propellant failure at low strain rates is the dewetting phenomenon occurring at the interface between the larger particles and the matrix. The maximum tensile strength is 0.48 MPa when the strain rate is 0.00119 s-1, and the maximum tensile strength is 0.37 MPa when the strain rate is 0.000119 s-1. The simulation results indicated a consistent trend in variation when comparing the simulation and experimental curves. This suggested that the established model exhibits a high level of reliability, and provides a promising approach for carrying out microstructural simulations of heterogeneous propellants in future. The mechanical behavior of the propellant can be effectively described by utilizing a mesoscopic finite element model that incorporates the superelastic constitutive model of the matrix and the bilinear cohesive model. This framework facilitates the representation of mesoscopic damage evolution, which consequently provides insights into the damage mechanism. Additionally, the utilization of such models assists in compensating for the limitations of damage evolution characterization experiments.

Morphological Characteristics, Ultrastructure, and Chemical Constituents of the Endotesta in Ginkgo (Ginkgo biloba L.).

Ginkgo biloba L. is a tree species of significant economic and ecological importance. Prior studies of the Ginkgo biloba seed coat have predominantly focused on the sarcotesta and sclerotesta, with less attention paid to the endotesta. In this study, the development and formation of Ginkgo endotesta were examined using light microscopy and transmission electron microscopy. The structural properties of the mature endotesta were analyzed using micro-CT imaging and scanning electron microscopy. The results indicate that the endotesta possess a membranous structure primarily originating from the inner bead peridium, a segment of bead core tissue, and the macrospore membrane. The endotesta from the middle constriction line to the chalazal end comprises a single layer with a greyish-white papery structure. In contrast, the endotesta was divided into two inner and two outer layers, from the middle constriction line to the micropylar end. The outer endosperm adheres closely to the sclerotesta, while the inner endosperm adheres to the seed kernel. The surface of the endotesta was irregularly raised, with thicker wax at the chalazal end, whereas the micropylar end demonstrated similar characteristics with thinner wax and tumor layers. The endotesta contained 17 amino acids, 18 fatty acids, 10 trace elements, and 7 vitamins. Overall, its nutritional value was relatively well balanced.