Three-dimensional Micro-computed Tomography Research Articles

Interleukin-35 protein inhibits osteoclastogenesis and attenuates collagen-induced arthritis in mice.

Rheumatoid arthritis (RA) is a chronic autoimmune disease. Its pathological features include synovial inflammation, bone erosion, and joint structural damage. Our previous studies have shown that interleukin (IL)-35 is involved in the pathogenesis of bone loss in RA patients. In this study, we are further evaluating the efficacy of IL-35 on collagen-induced arthritis (CIA) in the mouse model.Male DBA/1J mice (n = 10) were initially immunized, 2 μg/mouse IL-35 was injected intraperitoneally every week for 3 weeks after the establishment of the CIA model. Clinical arthritis, histopathological analysis, and three-dimensional micro-computed tomography (3D micro-CT) were determined after the mice were anesthetized on the 42th day. In vitro, RANKL/M-CSF induced mouse preosteoclasts (RAW264.7 cells line) was subjected to antiarthritis mechanism study in the presence of IL-35.The results of clinical arthritis, histopathological analysis, and 3D micro-CT, the expression of RANK/RANKL/OPG axis, inflammatory cytokines, and osteoclastogenesis-related makers demonstrated decreasing severity of synovitis and bone destruction in the ankle joints after IL-35 treatment. Furthermore, IL-35 attenuated inflammatory cytokine production and the expression of osteoclastogenesis-related makers in a mouse preosteoclasts cell line RAW264.7. The osteoclastogenesis-related makers were significantly reduced in IL-35 treated RAW264.7 cells line after blockage with the JAK/STAT1 signaling pathway. These results demonstrated that IL-35 protein could inhibits osteoclastogenesis and attenuates CIA in mice.We concluded that IL-35 can exhibit anti-osteoclastogenesis effects by reducing the expression of inflammatory cytokines and osteoclastogenesis-related makers, thus alleviating bone destruction in the ankle joint and could be a potential therapeutic target for RA.

Internal vascular anatomy of the human lacrimal gland: A protocol based on cadaver dissection and three-dimensional micro-computed tomography

PurposeTo evaluate the feasibility of studying the vascular supply of the orbital and palpebral lobes of the human lacrimal gland using micro-computed tomography (micro-CT) and microscopic dissection. MethodsThe lacrimal gland artery of a fresh parasagittalized cadaver head (male, aged 76 years) was infused with a lead oxide-latex mixture near the occipital pole of the gland. The entire lacrimal gland was imaged using micro-CT and 3D cinematic rendering (CR) and then dissected under a surgical microscope. ResultsMicro-CT and CR images showed well-demarcated internal vascular branches of the lacrimal artery and their distribution within the orbital and palpebral lobes. The entire course of the artery and its branches could be visualized by CR and microscopic dissection, with the former showing better spatial orientation and finer branching. The main artery runs along the free edge of the aponeurosis of the levator palpebrae superior muscle and lies in the isthmus portion of the gland (between the orbital and palpebral lobes). The branches of the main lacrimal artery include one branch to the orbital adipose tissue just before entering the gland, two branches to the orbital lobe (medial and lateral), and two branches to the palpebral lobe (medial and lateral). The main artery terminates as palpebral and orbital lobe branches in the lateral half of the lacrimal gland. ConclusionLatex and contrast-enhanced micro-CT is very well suited to visualize the vascular anatomy of the lacrimal artery within the gland. A large number of lacrimal gland examinations using the method presented here are required to demonstrate and understand the variability of the vascular anatomy of the human lacrimal gland.

Age-related changes in the midpalatal suture: Comparison between CBCT staging and bone micromorphology

The age-related maturation of the human midpalatal suture is challenging to predict, but critical for successful non-surgical rapid maxillary expansion (RME). While cone-beam computed tomography (CBCT) can be used to categorize the suture into stages, it remains unclear how well the stages predict the actual micromorphology of the palate. To address this clinically relevant question, we used CBCT together with three-dimensional micro-computed tomography (μCT) analysis on 24 human palate specimens from individuals aged 14–34 years. We first classified the specimens into stages (A-E) using CBCT images and then correlated the results with our comprehensive μCT analysis. Our analysis focused on several factors, including bone volume fraction (BV/TV), sutural width, volume, interdigitation, ossification, and their associations with age, CBCT stage, and sex. Our μCT analysis revealed a decrease in sutural width and volume after the age of 20 years, accompanied by sutural closure beginning in the palatal segment. The overall rate of ossification remained low but increased after the age of 20 years. No significant differences were found between males and females. Importantly, we also found no correlation between individual age and CBCT stages. Furthermore, there was no association between CBCT stages and patalal suture volume, ossification and interdigitation.Taken together, our findings cast doubt on the reliability of CBCT stage as a means of predicting skeletal maturity of the palatal suture, as it appears to lack the precision required to accurately assess the true micromorphology of the palatal suture. Future investigations should explore whether alternative CBCT parameters may be more useful in addressing the challenging question of whether RME requires surgical bone weakening.

Embryonic cranial cartilage defects in the Fgfr3Y367C /+ mouse model of achondroplasia.

Achondroplasia, the most common chondrodysplasia in humans, is caused by one of two gain of function mutations localized in the transmembrane domain of fibroblast growth factor receptor 3 (FGFR3) leading to constitutive activation of FGFR3 and subsequent growth plate cartilage and bone defects. Phenotypic features of achondroplasia include macrocephaly with frontal bossing, midface hypoplasia, disproportionate shortening of the extremities, brachydactyly with trident configuration of the hand, and bowed legs. The condition is defined primarily on postnatal effects on bone and cartilage, and embryonic development of tissues in affected individuals is not well studied. Using the Fgfr3Y367C/+ mouse model of achondroplasia, we investigated the developing chondrocranium and Meckel's cartilage (MC) at embryonic days (E)14.5 and E16.5. Sparse hand annotations of chondrocranial and MC cartilages visualized in phosphotungstic acid enhanced three-dimensional (3D) micro-computed tomography (microCT) images were used to train our automatic deep learning-based 3D segmentation model and produce 3D isosurfaces of the chondrocranium and MC. Using 3D coordinates of landmarks measured on the 3D isosurfaces, we quantified differences in the chondrocranium and MC of Fgfr3Y367C/+ mice relative to those of their unaffected littermates. Statistically significant differences in morphology and growth of the chondrocranium and MC were found, indicating direct effects of this Fgfr3 mutation on embryonic cranial and pharyngeal cartilages, which in turn can secondarily affect cranial dermal bone development. Our results support the suggestion that early therapeutic intervention during cartilage formation may lessen the effects of this condition.

Effect of Nd:YAG laser on bone formation in rat tibia defects: three-dimensional micro-computed tomography image analysis.

Nd:YAG laser is in common clinical use for the treatment of tissue incision, transpiration, and haemostasis in soft tissues. However, few studies have reported the effects of low-level laser therapy (LLLT) from Nd:YAG laser on bone healing. The aim of this study was to perform three-dimensional (3D) morphological evaluation of the photobiomodulation of Nd:YAG laser in bone defects in rat tibiae using micro-computed tomography CT (micro-CT) imaging. A bone defect was created in each tibia of 30 rats. The right side was treated with LLLT from Nd:YAG laser (LT group) daily until sacrifice and the left tibiae served as controls (control group). All tibiae underwent micro-CT imaging at 7, 14, and 21days after the operation. Three-dimensional image analysis of bone volume (BV) and bone surface area (BS) of new bone formation in the defects was performed and histologic analysis was conducted for all tibiae. Tibial BV and BS values were highest in both groups at 7days after the operation and decreased at 14days after operation. BV and BS values were both significantly higher in the LT group than in the control group at 7 and 14days. There was no significant difference between the groups for either metric at 21days. The present findings demonstrate that Nd:YAG laser simulates bone formation during the early healing period.

Evolution of hypoxia and hypoxia-inducible factor asparaginyl hydroxylase regulation in chronic kidney disease.

The roles of hypoxia and hypoxia inducible factor (HIF) during chronic kidney disease (CKD) are much debated. Interventional studies with HIF-α activation in rodents have yielded contradictory results. The HIF pathway is regulated by prolyl and asparaginyl hydroxylases. While prolyl hydroxylase inhibition is a well-known method to stabilize HIF-α, little is known about the effect asparaginyl hydroxylase factor inhibiting HIF (FIH). We used a model of progressive proteinuric CKD and a model of obstructive nephropathy with unilateral fibrosis. In these models we assessed hypoxia with pimonidazole and vascularization with three-dimensional micro-computed tomography imaging. We analysed a database of 217 CKD biopsies from stage 1 to 5 and we randomly collected 15 CKD biopsies of various severity degrees to assess FIH expression. Finally, we modulated FIH activity in vitro and in vivo using a pharmacologic approach to assess its relevance in CKD. In our model of proteinuric CKD, we show that early CKD stages are not characterized by hypoxia or HIF activation. At late CKD stages, some areas of hypoxia are observed, but these are not colocalizing with fibrosis. In mice and in humans, we observed a downregulation of the HIF pathway, together with an increased FIH expression in CKD, according to its severity. Modulating FIH in vitro affects cellular metabolism, as described previously. In vivo, pharmacologic FIH inhibition increases the glomerular filtration rate of control and CKD animals and is associated with decreased development of fibrosis. The causative role of hypoxia and HIF activation in CKD progression is questioned. A pharmacological approach of FIH downregulation seems promising in proteinuric kidney disease.

Analysis of the alveolar shape in 3-D.

Mechanical forces affect the alveolar shape, depending on location and tissue composition, and vary during the respiratory cycle. This study performs alveolar morphomics in different lobes of human lungs using models generated from three-dimensional (3-D) micro-computed tomography (microCT) images. Cylindrical tissue samples (1.6 cm × 2 cm) were extracted from two nontransplantable donor lungs (one ex-smoker and one smoker, 3 samples per subject) that were air-inflated and frozen solid in liquid nitrogen vapor. Samples were scanned with microCT (11 µm/voxel). Within representative cubic regions of interest (5.5 mm edge length), alveoli were segmented to produce corresponding 3-D models from which quantitative data were obtained. The surface of segmented alveoli (n_alv_total = 23,587) was divided into individual planar surfaces (facets) and angles between facet normals were calculated. Moreover, the number of neighboring alveoli was estimated for every alveolus. In this study, we examined intraindividual differences in alveolar morphology, which were reproducible in the lungs of two subjects. The main aspects are higher mean alveolar volumes (v_alv: 6.64 × 106 and 6.63 × 106 µm3 vs. 5.78 × 106 and 6.29 × 106 µm3) and surface sizes (s_alv: 0.19 and 0.18 mm2 vs. 0.17 mm2 in both lower lobes) in both upper lung lobes compared with the lower lobes. An increasing number of facets (f_alv) from top to bottom (12 and 14 in the upper lobes; 14 and 15 in the lower lobes), as well as a decreasing number of alveolar neighbors (nei_alv: 9 and 8 in the upper lobes; 8 and 7 in the lower lobes) from the upper lobes to the lower lobes were observed. We could observe an increasing ratio of alveolar entrance size to the surface size of the alveoli from top to bottom (S_ratio_alv: 0.71 and 0.64 in the upper lobes, 0.73 and 0.70 in the lower lobes). The angles between facet normals (ang_alv) were larger in the upper lobes (67.72° and 62.44°) of both lungs than in the lower lobes (66.19° and 61.30°). By using this new approach of analyzing alveolar 3-D data, which enables the estimation of facet, neighbor, and shape characteristics, we aimed to establish the baseline measures for in-depth studies of mechanical conditions and morphology.

Anatomical study of the adductor canal: three-dimensional micro-computed tomography, histological, and immunofluorescence findings relevant to neural blockade.

A precise anatomical understanding of the adductor canal (AC) and its neural components is essential for discerning the action mechanism of the AC block. We therefore aimed to clarify the detailed anatomy of the AC using micro-computed tomography (micro-CT), histological evaluation, and immunofluorescence (IF) assays. Gross dissections of 39 thighs provided morphometric data relevant to injection landmarks. Serial sectional images of the AC were defined using micro-CT and ultrasonography. The fascial and neural structures of the AC proper were histologically evaluated using Masson's trichrome and Verhoeff-Van Gieson staining, and double IF staining using choline acetyltransferase (ChAT) and neurofilament 200 antibodies. The posteromedial branch insertion of the nerve to vastus medialis (NVM) into the lateral border of the AC proper was lower (14.5 ± 2.4 cm [mean ± SD] above the base of the patella) than the origin of the proximal AC. The AC consists of a thin subsartorial fascia in the proximal region and a thick aponeurosis-like vastoadductor membrane in the distal region. In the proximal AC, the posteromedial branch of the NVM (pmNVM) consistently contained both sensory and motor fibers, and more ChAT-positive fibers were observed than in the saphenous nerve (27.5 ± 11.2 / 104 vs. 4.2 ± 2.6 / 104 [counts/µm2], P < 0.001). Anatomical differences in fascial structures between the proximal and distal AC and a mixed neural component of the neighboring pmNVM have been visualized using micro-CT images, histological evaluation, and IF assays.

104. Effects of cannabinoids on spinal fusion in a rat model

<h3>BACKGROUND CONTEXT</h3> The opioid epidemic is a public health crisis causing significant morbidity, mortality and economic costs nationwide. As a result, discovering alternative forms of pain management is becoming imperative. Medical marijuana is an option for a nonopioid analgesic and is under investigation for potential uses in fields such as oncology and chronic pain, but it is yet to be studied in the surgical setting. Specifically, its effects on bone healing are not fully understood, significantly affecting its potential analgesic efficacy for postorthopaedic surgical care. <h3>PURPOSE</h3> The goal of this this study is to determine the effect of cannabis derivatives, D9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on bone healing. The effects of marijuana on spinal arthrodesis specifically have yet to be investigated. We hypothesized that THC and CBD will not decrease bone healing in a rat model for spinal fusion. <h3>STUDY DESIGN/SETTING</h3> A basic science study utilizing a validated experimental model to assess spinal fusion performed on rats. <h3>PATIENT SAMPLE</h3> N/A (Sprague-Dawley rats were used for this basic science study). <h3>OUTCOME MEASURES</h3> Manual palpation was done to assess strength of the L4-L5 arthrodesis on all rats. Twelve rats underwent lumbar three-dimensional micro-computed tomography (μCT) imaging and histological analysis. The remaining half were subjected to quantitative polymerase chain reaction (qPCR) analyses which are currently pending. The μCT bone analysis was comprised of quantifying the ratio of bone volume (BV) to total volume (TV) within each volume of interest (VOI), as well as bone mineral density (BMD) and tissue mineral density (TMD) for the corresponding VOI. During follow-up, one animal from the saline and one from the combination group were lost due to wound dehiscence. Kruskal-Wallis test followed by Dunn's multiple comparisons test was performed using GraphPad Prism. Two-tailed values of p < 0.05 were considered statistically significant. <h3>METHODS</h3> Animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC). Twenty-eight adult Sprague-Dawley rats were used for this study. Utilizing allogenic bone graft (4 donor rats), posterolateral inter-transverse lumbar fusion at the L4-L5 level was performed under surgical microscopy. The animals were divided into four groups of 6, each receiving 0.1ml intraperitoneal injections weekly as follows: placebo (saline), 5 mg/kg THC, 5 mg/kg CBD, and a combination of 5 mg/kg THC and 5 mg/kg CBD (combo). Eight weeks postsurgery, animals were euthanized and fusions were assessed. <h3>RESULTS</h3> The combination treatment group had the highest fusion rates, with 66.7% demonstrating full fusion and 33.3% demonstrating partial fusion. This was followed by the THC group demonstrating 60% of rats with full fusion, 20% with partial fusion, and 20% with no fusion. Fusion rates were lower in the CBD and saline groups. However, the fusion rates were not significantly different between the treatment groups based on our manual palpation scoring. Callus formation was visually more extensive in THC and Combo treatments on μCT 3D reconstruction images. This observation was confirmed though μCT data, in which bone volume fraction (BV/TV) was significantly higher for the CBD and THC treatment groups compared to the saline treatment group (P <0.05). BMD and TMD values were higher for all cannabis treatment groups compared to the saline treatment group, though not statistically significant. <h3>CONCLUSIONS</h3> This study preliminarily demonstrates that CBD and THC have no adverse effect on bone regeneration and rate of spinal fusion in rats. Cannabinoids may possess osteoinductive properties which require further investigation. Future larger animal studies should further investigate the effects of cannabinoid receptor agonists on bone healing and formation, with additional exploration of cannabinoid receptor agonists as a potential alternative approach to postoperative analgesia following spinal fusion and other procedures requiring bone formation. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Attenuation of Bone Formation through a Decrease in Osteoblasts in Mutant Mice Lacking the GM2/GD2 Synthase Gene.

The ganglioside GD1a has been reported to promote the differentiation of mesenchymal stem cells to osteoblasts in cell culture systems. However, the involvement of gangliosides, including GD1a, in bone formation in vivo remains unknown; therefore, we herein investigated their roles in GM2/GD2 synthase-knockout (GM2/GD2S KO) mice without GD1a. The femoral cancellous bone mass was analyzed using three-dimensional micro-computed tomography. A histomorphometric analysis of bone using hematoxylin and eosin (HE) and tartrate-resistant acid phosphatase was performed to examine bone formation and resorption, respectively. Calcein double labeling was also conducted to evaluate bone formation. Although no significant differences were observed in bone mass or resorption between GM2/GD2S KO mice and wild-type (WT) mice, analyses of the parameters of bone formation using HE staining and calcein double labeling revealed less bone formation in GM2/GD2S KO mice than in WT mice. These results suggest that gangliosides play roles in bone formation.

A Micro-computed Tomography Database and Reference Implementation for Parallel Computations of Trabecular Thickness and Spacing

We provide a well-defined accurate brute force implementation without approximations as a reference to support future development of correct and fast algorithms to measure the trabecular thickness and spacing. Using artificial ellipsoid examples, the systematic error is shown to be related to the voxelization, which can be reduced by upsampling. Furthermore, we collected a database of 40 three-dimensional micro-computed tomography images of trabecular bone regions of a sheep femur. With the coverage of a broad range of trabecular thickness and spacing, the database is suitable for assessing the correctness of algorithms for the measurements of trabecular thickness and spacing. The bone data is shared publicly in the online repository ‘Figshare’ and the brute force code is freely available in Code Ocean. Scientists are encouraged to implement faster algorithms, e.g., graphic processing unit-accelerated, with accurate or controlled approximate behaviour to compute trabecular thickness and spacing. Especially, the provided data can be re-employed together with the reference algorithm to evaluate their accuracies.

Craniomaxillofacial morphology in a murine model of ephrinB1 conditional deletion in osteoprogenitor cells

ObjectiveEFNB1 mutation causes craniofrontonasal dysplasia (CFND), a congenital syndrome associated with craniomaxillofacial anomalies characterised by coronal craniosynostosis, orbital hypertelorism, and midface dysplasia. The aim of this murine study was to investigate the effect of the EfnB1 conditional gene deletion in osteoprogenitor cells on the craniomaxillofacial skeletal morphology. DesignThe skulls of male and female mice, in which EfnB1 was deleted by Cre (a site-specific DNA recombinase) under the control of the Osterix (Osx) promoter (EfnB1OB-/-), were compared to those without EfnB1 deletion (Osx:Cre control) at two ages (4 and 8 weeks; n = 6 per group). The three-dimensional micro-computed tomography reconstructions were prepared to calculate 17 linear measurements in the cranial vault (brain box), midface and mandible. Coronal and sagittal sutures from the 8-week-old mice were also subjected to histological examination. ResultsEfnB1OB-/- mice displayed significantly larger cranial height, larger interorbital and nasal widths, smaller maxillary width than controls by 8 weeks (p < 0.05), but mandibular size was not significantly different (p > 0.05). Binomial testing showed significantly smaller EfnB1OB-/- skulls at 4 weeks but larger at 8 weeks (p < 0.05). Histological examination revealed increased bony fusion and fibrous connective tissue deposition at the coronal suture of EfnB1OB-/- mice compared with controls. ConclusionsCraniofacial phenotype of the murine model of EfnB1 deletion in osteoprogenitor cells partially represents the human CFND phenotype, with implications for better understanding mechanisms involved in skeletal morphogenesis and malocclusion.

Age-related osteogenesis on lateral force application to rat incisor – Part II: Bony recession and cortical remodeling

Objective: The aim of this study is to analyze the age-related changes in the bony recession and cortical bone remodeling induced by lateral orthodontic tooth movement, using a three-dimensional micro-computed tomography (CT) analysis. Material and Methods: A total of 40 male Sprague-Dawley rats were divided into two distinct age groups (young, 10 weeks and adult, 52 weeks). Double-helical springs exerting 40 g of force were applied to central incisors to analysis of changes in lateral cortical bone and tooth movement with age and time. The young and adult rats were divided into four subgroups, T0 (0 week), T1 (1 week), T2 (2 weeks), and T3 (3 weeks), depending on the period of wearing the appliance. Micro-CT image was taken on each dissected pre-maxilla specimen. In each subgroup, distance between the center of teeth, suture width, tooth displacement, bony recession, and bone volume was evaluated. Results: The changes in the distance between the center of teeth and the suture width were significantly greater in the young group. However, the change in the tooth displacement showed no significant difference between groups. In the young group, bony recession of outer cortical layer was observed at T1 (P &lt; 0.05), but the amount of recession gradually decreased at T2 and T3. In contrast, in the adult group, bony recession increased gradually over observation period (P &lt; 0.05). The bone volume decreased at T1 (P &lt; 0.05), but recovered at T2 and T3 in both groups. Conclusion: The compensatory bone formation occurs in the pressure side of cortical bone more significantly in the young group than in the adult according to the lateral displacement of incisor in rats. The reduced bone reaction in the adult is considered a limiting factor of the excessive tooth movement in the compromised treatment of skeletal malocclusion.

Frictional Forces of Three Types of Lingual Appliance with Self-ligating Mechanisms

The present study compared the frictional forces of three types of self-ligating lingual appliances. The lingual appliances (2D, Forestadent; Alias, Ormco; and Clippy L, Tomy International) consisted of a self-ligating bracket (second premolar) and two self-ligating tubes (first and second molars) bonded to a stainless steel jig and attached to a "drawing-friction tester." Full-size and non-full-size stainless steel archwires were tested, and the static and kinetic friction acting on six lingual appliance/wire combinations was estimated (n = 5). Three-dimensional micro-computed tomography (micro-CT) analysis of each premolar bracket was performed. The frictional forces were compared between the bracket/wire combinations using the Kruskal-Wallis and Mann-Whitney U tests. The Alias and Clippy L bracket/wire combinations had greater contact between the wire surfaces and bracket slots compared to the 2D bracket/wire combination. For all lingual appliances, the static and kinetic frictional forces were significantly higher for the full-size than non-full-size archwire. The 2D bracket, which had a wider outer wing, had less frictional force than the other appliances. The Alias, which had a narrower outer wing, had a significantly lower frictional force than the Clippy L. Frictional force was significantly higher for heavier full-size bracket/archwire combinations than for non-full-size archwires. The 2D bracket had lower frictional force due to its archwire-holding mechanism. The outer wing width may influence the frictional resistance. The frictional forces of self-ligating lingual appliances vary, and bracket design and archwire size may influence the frictional performance.

The mechanical origin of the radial shape in distichous phyllotaxy grass plants

Abstract Three-dimensional plant shapes are influenced by their phyllotaxy, which plays a significant role in their environmental adaptation. Grasses with distichous phyllotaxy have linearly aligned culms and usually have vertical fan-like shapes. Counterintuitively, some distichous phyllotaxy grasses have radial shapes. Here, we investigate the organ-level mechanism underlying radial shape development in the distichous phyllotactic wild rice species (Oryza rufipogon). Detailed time-course phenotyping and three-dimensional micro-computed tomography showed that changes in the elevation angle in the main culm and azimuth angle in the primary tillers contribute to radial shape development. To infer the mechanical basis of the shape change, we simulated the movements of culms controlled by different kinematic factors. The computational models predicted that the combination of movements, including that controlled by negative gravitropism, produces the overall radial shape. This prediction was experimentally assessed. The analysis using a near-isogenic line of the gene, PROG1 for prostrate growth and the gravitropic mutant (lazy1) showed an association between genes and our model parameters. Our findings provide a simple, yet substantial, kinematic model for how the shape in distichous phyllotaxy plants changes as part of their adaptation to the surrounding environment.

Comparison of the skeletal features of two sympatric tree frogs (Hylidae:Hyla)—Hyla japonica and Hylasuweonensis—using three-dimensional micro-computed tomography

We used three-dimensional micro-computed tomography to compare the skeletal features of two species of male tree frogs with similar morphologies: the globally prevalent Hyla japonica and critically endangered Hyla suweonensis. One of the most prominent differences between the two species was the angle of the alary processes of the premaxilla. In H. suweonensis, the alary processes were inclined posteriorly at an angle of 77.05°, whereas in H. japonica, they were deflected at an angle of 93.27° (a difference of more than 16°). This difference accounts for the more protruded shape of H. suweonensis compared with that of H. japonica. Sizes and proportions related to skeletal compartments (e.g. skull, forelimb, vertebrae, and hindlimb) also differed between the two species, which is consistent with the general exterior observation that compared with H. japonica, H. suweonensis has a more acuminate snout and a more slender body. The full skeletal configuration could provide classification keys for the two sympatric species that will be applicable to ecological field surveys and conservation activities.

The impact of flow displacement patterns on hydraulic tortuosity for unsaturated flow

Hydraulic tortuosity is one of the key parameters used to characterize the fluid transport properties of porous media. One of the existing debates on hydraulic tortuosity is whether it is an intrinsic property or a correction factor to match the experimental data with a particular model. In this study, a series of immiscible displacement simulations with different capillary numbers and contact angles were established by using the phase field method based on three-dimensional micro-computed tomography images of porous media. Then, the vector-based tortuosity method based on the flow velocity field is used to predict the dynamic evolution of hydraulic tortuosity of unsaturated porous media. Interestingly, the transient hydraulic tortuosity at different flow displacement patterns shows different dynamic evolutions where the quasi-steady-state hydraulic tortuosity is related to both the fluid saturation and the characteristics of the trapped voids in the porous media. These phenomena can be explained by the complex and interesting pore-scale displacement events, including viscous self-correcting smoothing, noncooperative Haines jumps, capillary self-correcting smoothing, and corner flow.

Effect of Collagen-Enhanced Fibrin Sealant on Seroma Formation in a Rat Mastectomy Model

Background: Seromas are caused by leakage of lymphovascular fluid into postoperative dead space. This is the most common complication after reconstructive breast surgery. The purpose of this study is to demonstrate the utility of seroma-preventing substances by using a collagen-enhanced fibrin sealant on a rat mastectomy model.Methods: Thirty-six Sprague-Dawley rats were divided into three groups. After mastectomy and axillary lymph node dissection, normal saline was applied to the dead spaces in group 1 (control). In group 2, a collagen-enhanced fibrin sealant was applied, and in group 3, triamcinolone acetate solution was applied. Afterwards, the amount of seroma was measured by three-dimensional micro-computed tomography (3D micro-CT) volumetry analysis and manual aspiration after 7 and 14 days, respectively.Results: The volume of seroma were significantly reduced in groups 2 and 3 compared to group 1 in both 3D micro-CT volumetry analysis and manual aspiration on postoperative day 7 (P&lt;0.001). In addition, the results observed in day 14 also showed a decrease in the amount of seroma analyzed by CT in groups 2 and 3 compared to group 1 (P&lt;0.05). In histopathologic examination inflammation was observed more frequently in group 1 and angiogenesis was more active in group 2.Conclusion: The use of a collagen-enhanced fibrin sealant (Collaseal) is as effective as triamcinolone control injected in a rat mastectomy model.

Three-Dimensional Micro-Computed Tomography of the Adult Mouse Ovary.

In the mouse ovary, folliculogenesis proceeds through eight main growth stages, from small primordial type 1 (T1) to fully grown antral T8 follicles. Most of our understanding of this process was obtained with approaches that disrupted the ovary three-dimensional (3D) integrity. Micro-Computed Tomography (microCT) allows the maintenance of the organ structure and a true in-silico 3D reconstruction, with cubic voxels and isotropic resolution, giving a precise spatial mapping of its functional units. Here, we developed a robust method that, by combining an optimized contrast procedure with microCT imaging of the tiny adult mouse ovary, allowed 3D mapping and counting of follicles, from pre-antral secondary T4 (53.2 ± 12.7 μm in diameter) to antral T8 (321.0 ± 21.3 μm) and corpora lutea, together with the major vasculature branches. Primordial and primary follicles (T1–T3) could not be observed. Our procedure highlighted, with unprecedent details, the main functional compartments of the growing follicle: granulosa, antrum, cumulus cells, zona pellucida, and oocyte with its nucleus. The results describe a homogeneous distribution of all follicle types between the ovary dorsal and ventral regions. Also, they show that each of the eight sectors, virtually segmented along the dorsal-ventral axis, houses an equal number of each follicle type. Altogether, these data suggest that follicle recruitment is homogeneously distributed all-over the ovarian surface. This topographic reconstruction builds sound bases for modeling follicles position and, prospectively, could contribute to our understanding of folliculogenesis dynamics, not only under normal conditions, but, importantly, during aging, in the presence of pathologies or after hormones or drugs administration.

Upscaling Reservoir Rock Porosity by Fractal Dimension Using Three-Dimensional Micro-Computed Tomography and Two-Dimensional Scanning Electron Microscope Images

Abstract Scaling porosity of sedimentary rocks from the scale of measurement to the scale of interest is still a challenge. Upscaling of porosity can assist to accurately predict other petrophysical properties of rock at multiple scales. In this study, we use the two-dimensional (2D) scanning electron microscope (SEM) and three-dimensional (3D) X-ray micro-computed tomography (micro-CT) image to upscale porosity from the image scale to the core plug scale. A systematic imaging plan is deployed to capture rock properties of a carbonate and a sandstone sample, which are sensitive to the fractal nature of these rocks. Image analysis records wider pore spectrum (0.12–50 µm) in the carbonate sample than in sandstone (0.12–30 µm). The fractal dimensions are also higher in the carbonate than in the sandstone sample. Median, volume-weighted average of pore radius, and fractal dimensions derived from the image analysis are used as inputs in this equation. The results of the present study using this equation yielded to the best results on a resolution of 2.5 µm/voxel in the sandstone and 2.01 µm/voxel resolution in the carbonate sample for 3D micro-CT images, where fractal-scaling porosity matches well with the porosity measured at the core plug scale. The 2D SEM images provided a good estimation of porosity in the sandstone sample, where micro-CT imaging techniques could not capture the full pore spectrum. The fractal porosity equation showed promising results and offers a potential alternative way to estimate porosity when there are no routine core measurements available.