3D micro-CT Research Articles

Lack of genotoxicity of iron oxide maghemite (γ-Fe2O3) and magnetite (Fe3O4) nanoparticles to Oreochromis niloticus after acute exposures.

Iron oxide nanoparticles (FeO-NPs) are widely used in scientific and technological fields. Environmental concerns have been raised about residual FeO-NPs levels as their toxicity and bioaccumulative potential are not well understood. Oreochromis niloticus were exposed to nanoparticles of γ-Fe2O3 and Fe3O4. Micro-CT 3D image and grayscale graphic assessments revealed the accumulation of radiopaque material in the digestive tract of fish exposed to FeO-NPs. Histological analysis showed the presence of such NPs in the hepatopancreas, gills, kidneys, and muscles. No genotoxicity occurred, through micronucleus test and comet assay in peripheral erythrocytes. Body clearance was confirmed by iron-content reduction in organisms exposed to FeO-NPs after recovery period. No tissue injuries were observed in the exposed animals which may be attributed to the absence or low toxicity of iron oxide nanoparticles under the study conditions. O. niloticus showed tolerance to sublethal exposures to FeO-NPs.

A New Multi-Scale Method to Evaluate the Porosity and MICP Curve for Digital Rock of Complex Reservoir

The evaluation of rock porosity and the mercury injection capillary pressure (MICP) curve is fundamental for oil and gas exploration and production. Digital rock (DR) technology, incorporating 3D micro-CT imaging and numerical methods, has been widely employed to predict these properties. However, analyzing the pore structure of heterogeneous rocks, such as fractured rocks or glutenite, solely through single-scale DR analysis poses challenges. Existing upscaling methods have limitations in fully representing the complete range of pore structures at different scales, with limited comparison to experimental data. To address this, we propose a novel method that upscales porosity and simulates the MICP curve from nano-scale to core scale by merging results from micro-CT (at resolutions of 35 μm and 2 μm) and SEM (at resolutions of 6.5 nm and 65 nm). We validate the developed DR model by applying it to sandstones, glutenite, and igneous rocks, and achieve excellent agreement between the experimental data and the multi-scale DR model across 67 samples. The results demonstrate that the multi-scale model effectively captures the porosity and pore structures across the entire range. In contrast, the single digital rock (DR) model underestimates the porosity measurements for both homogeneous sandstones and heterogeneous cores. While the MICP model based on a single DR proves suitable for homogeneous rock samples, it introduces noticeable discrepancies when applied to heterogeneous rock samples. The developed multi-scale method significantly enhances the confidence in using DR to assess the pore structure of complex rocks.

Impact of Chitosan-Coated Implants on the Alveolar Ridge: Preliminary MicroCT and Radiographic Study in a Canine Model.

To compare crestal bone loss (CBL) 12 weeks after immediate implant placement in the mandible of a canine model between titanium (Ti) implants with a conventional etched surface (SLA type) and Ti implants coated with chitosan (Cht). A total of 48 Ti-Al16-V4 implants (24 experimental and 24 control) with an internally connected tapered screw design were randomly placed into six canine maxillae, 4 per hemiarch. The experimental implants were coated with Cht by immersion and sterilized with ethylene oxide. Primary stability was measured using the Osstell device, and no grafting materials were used. The 3D microCT measurements included crestal bone volume (CBV) and bone volume change in crestal area (ΔCBV), which were considered outcome measures. Parallelized periapical radiographs were also taken at the time of implant placement and after 12 weeks to assess changes in crestal bone levels. In terms of volumetric changes, it was observed that the experimental group showed better results than the control group (P = .049 and P = .303, respectively). Regarding the implant sites, no significant differences were found between the experimental implant sites and control sites. The implants placed at P4 level in the experimental group obtained the best result (P = .041). The linear data obtained from the periapical radiographs indicated greater bone loss in the control group compared to the experimental group (3.2 ± 0.45 mm and 2.75 ± 0.55 mm, respectively). Despite the better results obtained for the Cht-coated surface group, further preclinical studies are necessary to confirm these results.

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.

Costal Cartilage Graft Repair Osteochondral Defect in a Mouse Model.

Osteochondral defects develop into osteoarthritis without intervention. Costal cartilage can be utilized as an alternative source for repairing osteochondral defect. Our previous clinical study has shown the successful osteochondral repair by costal cartilage graft with integration into host bone bed. In this study, we investigate how cartilaginous graft adapt to osteochondral environment and the mechanism of bone-cartilage interface formation. Costal cartilage grafting was performed in C57BL/6J mice and full-thickness osteochondral defect was made as control. 3D optical profiles and micro-CT were applied to evaluate the reconstruction of articular cartilage surface and subchondral bone as well as gait analysis to evaluate articular function. Histological staining was performed at 2, 4, and 8 weeks after surgery. Moreover, costal cartilage from transgenic mice with fluorescent markers were transplanted into wild-type mice to observe the in vivo changes of costal chondrocytes. At 8 weeks after surgery, 3D optical profiles and micro-CT showed that in the graft group, the articular surface and subchondral bone were well preserved. Gait analysis and International Cartilage Repair Society (ICRS) score evaluation showed a good recovery of joint function and histological repair in the graft group. Safranin O staining showed the gradual integration of graft and host tissue. Costal cartilage from transgenic mice with fluorescent markers showed that donor-derived costal chondrocytes turned into osteocytes in the subchondral area of host femur. Costal cartilage grafting shows both functional and histological repair of osteochondral defect in mice. Graft-derived costal chondrocytes differentiate into osteocytes and contribute to endochondral ossification.

Genetic interactions between polycystin-1 and Wwtr1 in osteoblasts define a novel mechanosensing mechanism regulating bone formation in mice

Molecular mechanisms transducing physical forces in the bone microenvironment to regulate bone mass are poorly understood. Here, we used mouse genetics, mechanical loading, and pharmacological approaches to test the possibility that polycystin-1 and Wwtr1 have interdependent mechanosensing functions in osteoblasts. We created and compared the skeletal phenotypes of control Pkd1flox/+;Wwtr1flox/+, Pkd1Oc-cKO, Wwtr1Oc-cKO, and Pkd1/Wwtr1Oc-cKO mice to investigate genetic interactions. Consistent with an interaction between polycystins and Wwtr1 in bone in vivo, Pkd1/Wwtr1Oc-cKO mice exhibited greater reductions of BMD and periosteal MAR than either Wwtr1Oc-cKO or Pkd1Oc-cKO mice. Micro-CT 3D image analysis indicated that the reduction in bone mass was due to greater loss in both trabecular bone volume and cortical bone thickness in Pkd1/Wwtr1Oc-cKO mice compared to either Pkd1Oc-cKO or Wwtr1Oc-cKO mice. Pkd1/Wwtr1Oc-cKO mice also displayed additive reductions in mechanosensing and osteogenic gene expression profiles in bone compared to Pkd1Oc-cKO or Wwtr1Oc-cKO mice. Moreover, we found that Pkd1/Wwtr1Oc-cKO mice exhibited impaired responses to tibia mechanical loading in vivo and attenuation of load-induced mechanosensing gene expression compared to control mice. Finally, control mice treated with a small molecule mechanomimetic, MS2 that activates the polycystin complex resulted in marked increases in femoral BMD and periosteal MAR compared to vehicle control. In contrast, Pkd1/Wwtr1Oc-cKO mice were resistant to the anabolic effects of MS2. These findings suggest that PC1 and Wwtr1 form an anabolic mechanotransduction signaling complex that mediates mechanical loading responses and serves as a potential novel therapeutic target for treating osteoporosis.

Microcomputed tomography (micro-CT) analysis of apical mandibular premolar in relation to clinical sign presentation: An in vitro study

IntroductionVariations in anatomic apex and apical foramina of root canals are common in different teeth types. The sophisticated 3D micro-CT aids researchers in investigating the apical morphology, such as the apical foramen (AF) and constriction (AC). ObjectivesTo measure the length between the foramen and the apex and the physiological length to the apex, in lower premolar teeth. Furthermore, a measurement was conducted on the average length from the foramen to the apex of the lower premolar teeth with respect to the presence of clinical and non-clinical signs. MethodsA total of 80 lower premolar teeth were selected based on the inclusion criteria. All samples were scanned using micro-CT ZEISS X-Radia (17 µm), and the datasets were analysed. The root canal AF and AC were reconstructed using Drishti software (V3.0) by utilising a 4-digit system code in millimetres (mm). ResultsMore than half of the lower premolars (n = 47, 58.8 %) demonstrated a clinical signs presentation, while the rest had a non-clinical sign (n = 33, 41.3 %). There was a significant difference (p = 0.013) between the non-clinical and clinical groups in the mean length from the apical foramen to the apex (AFA) at 0.59 mm and 0.47 mm, respectively. Meanwhile, the non-clinical and clinical mean length from apical constriction to apex (ACA) were 0.75 mm and 0.73 mm, and the mean length from AF to AC (AFC) was 0.48 mm and 0.53 mm, respectively. Nonetheless, no significant differences were detected between the ACA and AFC of non-clinical and clinical groups. ConclusionThe clinical signs presentation observed in lower premolars mainly affected the apical morphology, particularly the position and length of the root AF, and less so the AC position and length. Therefore, the information is useful for clinical purposes.

Mechanically robust, flexible hybrid tactile sensor with microstructured sensitive composites for human-cyber-physical systems

Advances in human-cyber-physical system (HCPS) requires multiple and multimodal sensory network to address the challenge of human-machine relationships, posing substantial potential for human health monitoring and human-centric smart manufacturing. However, combining electrical sensitivity and mechanical robustness of flexible sensors with simple device structure is still challenging. This work presents a flexible porous bimodal pressure sensor (PBPS) by fabricating 3D microstructured sensitive porous carbon-nanotubes composites (PCNC). The multi-layered PBPS can offer the ability to switch between piezoresistive and piezocapacitive sensing modes without altering the device structure, enhancing mechanical stability of device under loading/unloading cycles. This versatility allows for the detection of hardness discrimination, grabbing sensing, and dynamic human physiological signal recognition, which possess superior pressure sensing performances with a high sensitivity (0.1059 kPa−1 in piezoresistive mode, 0.2054 kPa−1 in capacitive mode), wide measuring range (0–25 kPa), rapid response time (<130 ms in piezoresistive mode, <55 ms in piezocapacitive mode), and long-term durability (>3000 cycles). Furthermore, we proposed a mechanical constitutive model to elucidate the sensing mechanism of microstructured PCNC by 3D micro-CT based modeling and experimental data. Finally, we employed multiple PBPSs as sensing elements to real-time monitor 3D printing manufacturing stress, structure assembling stress, and human physiology signals in HCPS, indicating the potential applications of PBPS ranging from monitoring human health to facilitating intelligent manufacturing.

Comparative analysis of hydrogen, methane and nitrogen relative permeability: Implications for Underground Hydrogen Storage

Underground Hydrogen Storage (UHS) is an emerging technology which aims to store terawatt-scale energy in the subsurface to alleviate daily and seasonal fluctuations in the ever-increasing renewable energy market. Depleted gas reservoirs and aquifers will be the main targets of storage which requires an understanding of the interaction between formation or cushion gas with native brine. A comprehensive comparison of the petrophysical and two-phase flow properties of the hydrogen-water, methane-water and nitrogen-water systems at in-situ conditions is the focus of our work. We conduct steady-state relative permeability experiments at 2.13 MPa and 298 K using identical capillary numbers of Nc=2.92×10−7 for all three systems. The saturation and in-situ contact angles are determined with segmentation of 3D micro-CT images. The contact angle of each system is almost identical at the irreducible water saturation, Swi, 44°, 46°, 45°, respectively, as is the interfacial tension of 72.0, 71.5 and 71mN/m, respectively. The capillary pressure-saturation relationships for each system have a maximum difference of 3.8 % which leads to approximately equivalent relative permeability in the Bentheimer sandstone core. The end-point relative permeabilities are krg0=0.049, krg0=0.045 and krg0=0.062 at irreducible water saturations of Swi=0.24, Swi=0.25 and Swi=0.23, respectively. All three gases demonstrate equivalent flow properties which indicates that both nitrogen and methane are suitable analogue gases for laboratory multiphase flow experiments and cushion gas to improve safety and the economics of commercial UHS projects. The results enable history matched depleted gas reservoir performance to be used as a guide for UHS.

The diploic venous system in Homo neanderthalensis and fossil Homo sapiens: A study using high-resolution computed tomography.

The diploic venous system has been hypothesized to be related to human brain evolution, though its evolutionary trajectory and physiological functions remain largely unclear. This study examines the characteristics of the diploic venous channels (DCs) in a selection of well-preserved Homo neanderthalensis and Upper Paleolithic Homo sapiens crania, searching for the differences between the two taxa and exploring the associations between brain anatomy and DCs. Five H. neanderthalensis and four H. sapiens fossil specimens from Western Europe were analyzed. Based on Micro-CT scanning and 3D reconstruction, the distribution pattern and draining orifices of the DCs were inspected qualitatively. The size of the DCs was quantified by volume calculation, and the degree of complexity was quantified by fractal analyses. High-resolution data show the details of the DC structures not documented in previous studies. H. neanderthalensis and H. sapiens specimens share substantial similarities in the DCs. The noticeable differences between the two samples manifest in the connecting points surrounding the frontal sinuses, parietal foramina, and asterional area. This study provides a better understanding of the anatomy of the DCs in H. neanderthalensis and H. sapiens. The connection patterns of the DCs have potential utility in distinguishing between the two taxa and in the phylogenetic and taxonomic discussion of the Neandertal-like specimens with controversial taxonomic status.

The impact of (simulated) resolution on breast cancer diagnosis based on high-resolution 3D micro-CT microcalcification images.

Breast microcalcifications (MCs) are considered to be a robust marker of breast cancer. A machine learning model can provide breast cancer diagnosis based on properties of individual MCs - if their characteristics are captured at high resolution and in3D. The main purpose of the study was to explore the impact of image resolution (8µm, 16µm, 32µm, 64µm) when diagnosing breast cancer using radiomics features extracted from individual high resolution 3D micro-CT MCimages. Breast MCs extracted from 86 female patients were analyzed at four different spatial resolutions: 8µm (original resolution) and 16µm, 32µm, 64µm (simulated image resolutions). Radiomic features were extracted at each image resolution in an attempt, to find a compact feature signature allowing to distinguish benign and malignant MCs. Machine learning algorithms were used for classifying individual MCs and samples (i.e., patients). For sample diagnosis, a custom-based thresholding approach was used to combine individual MC results into sample results. We conducted classification experiments when using (a) the same MCs visible in 8µm, 16µm, 32µm, and 64µm resolution; (b) the same MCs visible in 8µm, 16µm, and 32µm resolution; (c) the same MCs visible in 8µm and 16µm resolution; (d) all MCs visible in 8µm, 16µm, 32µm, and 64µm resolution. Accuracy, sensitivity, specificity, AUC, and F1 score were computed for eachexperiment. The individual MC results yielded an accuracy of 77.27%, AUC of 83.83%, F1 score of 77.25%, sensitivity of 80.86%, and specificity of 72.2% at 8µm resolution. For the individual MC classifications we report for the F1 scores: a 2.29% drop when using 16µm instead of 8µm, a 4.01% drop when using 32µm instead of 8µm, a 10.69% drop when using 64µm instead of 8µm. The sample results yielded an accuracy and F1 score of 81.4%, sensitivity of 80.43%, and specificity value of 82.5% at 8µm. For the sample classifications we report for F1 score values: a 6.3% drop when using 16µm instead of 8µm, a 4.91% drop when using 32µm instead of 8µm, and a 6.3% drop when using 64µm instead of 8µm. The highest classification results are obtained at the highest resolution (8µm). If breast MCs characteristics could be visualized/captured in 3D at a higher resolution compared to what is used nowadays in digital mammograms (approximately 70µm), breast cancer diagnosis will beimproved.

Prediction of dispersion and attenuation on elastic wave velocities in partially saturated rock based on the fluid distribution obtained from three-dimensional (3D) micro-CT images

Elastic wave attenuation in partially saturated porous rock is primarily due to wave-induced fluid flow, which arises from the contrast in compressibility between air and water and is influenced by the water distribution within the rock. We propose a method for constructing a numerical model that predicts mesoscopic dispersion and attenuation. Initially, we use fluid distribution data sourced from 3D X-ray Computed Tomography images to construct the numerical model, utilizing Biot’s poroelastic equations as the governing equations. Subsequently, we implement the finite element method to derive solutions for the numerical model. Our focus is centered on two key challenges: 1) reducing memory cost, and 2) efficiently handling element intersection during the meshing process. The solutions illustrate the evolution of fluid pressure distribution and the frequency-dependent advancement of the elastic moduli, coupled with their corresponding attenuation. Ultimately, we compare these numerical predictions with previously published experimental data from a study on partially saturated Indiana limestone. The considerable agreement between our numerical results and the experimental data confirms the validity of our method, which crucially incorporates the actual fluid distribution (captured from 3D CT images) as a vital input.

Dispersion of hydrophobic waste amorphous carbon powder in cementitious environment and its effect on the permeability of cement paste

A Proper dispersion of powder-based hydrophobic admixtures in cementitious composites is challenging due to the presence of water. Studies have shown that amorphous carbon powder (ACP), a hydrophobic by-product of refining waste materials of paraffin production can be used as a hydrophobic agent. However, mixing methods and dispersing agents for modifying cementitious materials with ACP can significantly impact their mechanical properties, workability, water-repellency (hence the durability), and dispersion quality of ACP. Lack of information about the extent of their impact on different aspects mentioned above can hinder the practical use of ACP as a hydrophobic agent. To fill this gap, the objective of this study is to comprehensively investigate factors in the dispersion of ACP in cementitious materials and the tradeoff between mechanical properties and water permeability of ACP-modified cementitious materials when more than one mixing method is adopted. The impacts of different dispersing agents and mixing methods, including ultrasonication, dry mixing, and after mixing, on dispersion quality of ACP in cementitious environment analogous with aqueous solutions and hardened cement paste were assessed. Polycarboxylate ether-based superplasticizer (PCE) proved to be the most effective dispersing agent. Compressive strength of ACP modified cement paste can be increased or decreased with or without the workability reduction effect of ACP along with PCE respectively. Based on volume fraction of ACP clusters in X-ray micro-CT 3D reconstruction of hardened cement paste, ultrasonication was identified as the most effective mixing method and dry mixing was the worst in terms of achieving a uniform distribution of ACP in cement paste. However, all mixing methods presented more than 85% volume fraction of uniformly dispersed ACP areas with no major difference in terms of hydrophobic modification capability. Modifying cement paste with a higher amounts of ACP (5 to 15% by weight of cement) substantially increased water contact angle (up to 171% for w/c ratio of 0.35) and decreased water absorption. The hydrophobic modification capability of ACP increases with a decrease in the quality of cement paste and is diminished by the presence of PCE. Consequently, without PCE, water absorption rate was reduced by up to 92% in similar ACP modified cement paste samples, which also led to a major reduction in compressive strength.

Extraction of the Microstructure of Wool Fabrics Based on Structure Tensor.

The trends of "fashionalization", "personalization" and "customization" of wool fabrics have prompted the textile industry to change the original processing design based on the experience of engineers and trial production. In order to adapt to the promotion of intelligent production, the microstructure of wool fabrics is introduced into the finishing process. This article presents an automated method to extract the microstructure from the micro-CT data of woven wool fabrics. Firstly, image processing was performed on the 3D micro-CT images of the fabric. The raw grayscale data were converted into eigenvectors of the structure tensor to segment the individual yarns. These data were then used to calculate the three parameters of diameter, spacing and the path of the center points of the yarn for the microstructure. The experimental results showed that the proposed method was quite accurate and robust on woven single-ply tweed fabrics.

Quantitative analysis of small coronary artery calcium detectability with an accurate simulation and validation on a clinical CT scanner.

The absence of coronary artery calcium (CAC) measured via CT is associated with very favorable prognosis, and current guidelines recommend low-density lipoprotein cholesterol (LDL-c) lowering therapy for individuals with any CAC. This motivates early detection of small granules of CAC; however, calcium scan sensitivity for detecting very low levels of calcium has not been quantified. In this work, the size limit of detectability of small calcium hydroxyapatite (CaHA) granules with clinical CAC scanning was assessed using validated simulations. CT projections of digital 3D mathematical phantoms containing small CaHA granules were simulated analytically; images were reconstructed using a filter designed to reproduce the point spread function of a specific commercial scanner, and a relationship of HU number versus diameter was derived. These simulation results were validated with experimental measurements of HU versus diameter from phantoms containing small granules of CaHA on a GE Revolution CT scanner in the clinic; ground truth measurements of the CaHA granule diameters were obtained using a Zeiss Xradia 510 Versa high-resolution 3D micro-CT imaging system. Using experimental measurements on the clinical CT scanner, detectability was quantified with a detectability index (d') using a non-prewhitened matched filter. The effect of changes to reconstruction slice thickness and reconstruction kernel on granule detectability was evaluated. Under typical clinical calcium scanning and reconstruction conditions, the minimum detectable diameter of a simulated spherical calcium granule with a clinically relevant CaHA density was 0.76mm. The minimum detectable volume was 2.4 times smaller on images reconstructed at a slice thickness of 0.625mm compared to 2.5mm. The detectability index d' increased by a factor of 1.7 when images were reconstructed with 0.625mm slices compared to 2.5mm slices. d' did not change when images were reconstructed with the high-resolution BONE filter compared to the less sharp STANDARD resolution filter on the GE Revolution CT. We have quantified detectability versus size of small calcium granules at the resolution limit of a widely available clinical CT scanner. Detectability increased significantly with reduced slice thickness and did not change with a sharper reconstruction kernel. The simulation can be used to calculate the trade-off between dose and CAC detectability.

Stacked ensemble machine learning for porosity and absolute permeability prediction of carbonate rock plugs

This study employs a stacked ensemble machine learning approach to predict carbonate rocks' porosity and absolute permeability with various pore-throat distributions and heterogeneity. Our dataset consists of 2D slices from 3D micro-CT images of four carbonate core samples. The stacking ensemble learning approach integrates predictions from several machine learning-based models into a single meta-learner model to accelerate the prediction and improve the model's generalizability. We used the randomized search algorithm to attain optimal hyperparameters for each model by scanning over a vast hyperparameter space. To extract features from the 2D image slices, we applied the watershed-scikit-image technique. We showed that the stacked model algorithm effectively predicts the rock's porosity and absolute permeability.

#6465 MIR-451B AND CHRONIC KIDNEY DISEASE: A NOVEL TARGET TO MODULATE RENAL VEGF SIGNALING

Abstract Background and Aims Chronic kidney disease (CKD) is a progressive disorder that affects over 15% of adults worldwide. A major component of CKD pathophysiology is renal microvascular rarefaction and loss that pairs the progression of the disease and complications. We developed a translational swine model of CKD and showed that loss of renal function associates with a significant decrease in renal vascular endothelial growth factor (VEGF) signaling and progressive microvascular (MV) rarefaction. VEGF is a key endogenous cytokine for MV proliferation and repair, but underlying mechanisms of renal VEGF downregulation in CKD are unknown. We hypothesized that micro-RNA (miRNA)-mediated processes contribute to the downregulation of renal VEGF signaling in CKD. Method Unbiased renal micro-RNA (miRNA)-seq was performed in a swine model of CKD stage 3 (14 weeks of bilateral renal artery stenosis + atherogenic diet) and normal controls (n = 5/group). Micro-RNAs up- (&amp;gt;1.4 FC, p&amp;lt;0.05) and down-regulated (&amp;lt;0.7 FC, p&amp;lt;0.05) were identified, followed by target prediction analysis (miRwalk 3.0, Target Scan 7.2). Renal gene and protein expression of VEGF was measured by qPCR and western blot, respectively, and renal MV architecture was studied by 3D micro-CT. Results Unbiased miRNA-seq and target prediction analysis identified four miRs upregulated in the kidney of CKD pigs vs. controls, of which miR-451b (validated by qPCR), broadly conserved among species, was capable of targeting VEGFA (FC = 4.46, p = 0.04). Renal gene and protein expression of VEGF was downregulated in CKD vs. controls, associated with significant cortical and medullary microvascular rarefaction (Figure 1). Conclusion Our data suggest that post-transcriptional modulation of renal VEGF signaling may serve as a prominent mechanism of VEGF downregulation, which leads to MV rarefaction and disease progression in CKD. Furthermore, this work in progress identified a novel candidate (miR-451b) and may set the stage for its targeted modulation to preserve VEGF signaling as a potential strategy to protect the renal microvasculature in CKD.

TNFα-dependent mTOR activity is required for tenotomy-induced ectopic ossification in mice.

Ectopic ossifications often occur in skeletal muscles or tendons following local trauma or internal hemorrhage, and occasionally cause severe pain that limits activities of daily living. However, mechanisms underlying their development remain unknown. The right Achilles tendon in 8-week-old female or male mice was dissected. Some mice were injected intraperitoneally either with phosphate-buffered saline, dimethyl sulfoxide, cimetidine, rapamycin, celecoxib or loxoprofen for 10 weeks. One week after surgery, immunohistochemical analysis was performed for mTOR, TNFα or F4/80. Ten weeks after surgery, ectopic ossification at the tenotomy site was detected by 3D micro-CT. Ectopic ossification was seen at dissection sites in all wild-type mice by dissection of the Achilles tendon. mTOR activation was detected at dissection sites, and development of ectopic ossification was significantly inhibited by administration of rapamycin, an mTOR inhibitor, to wild-type mice. Moreover, administration of the histamine 2 blocker cimetidine, which reportedly inhibits ectopic ossification in tendons, was not effective in inhibiting ectopic ossification in our models. TNFα-expressing F4/80-positive macrophages accumulate at dissection sites and that ectopic ossification of the Achilles tendon dissection was significantly inhibited in TNFα-deficient mice in vivo. Ectopic ossification is significantly inhibited by administration of either celecoxib or loxoprofen, both anti-inflammatory agents, in wild-type mice. mTOR activation by Achilles tendon tenotomy is inhibited in TNFα-deficient mice. The TNFα-mTOR axis could be targeted therapeutically to prevent trauma-induced ectopic ossification in tendons.

Framework of magnetostrain responsive Ni–Mn–Ga microparticles driving magnetic field induced out-of-plane actuation of laminate composite

Ni–Mn–Ga single crystals (SC) exhibiting a giant magnetic field induced strain (MFIS), resulting from twin boundaries rearrangements, are excellent materials for novel actuators although enhanced brittleness and high costs are remaining the issues for applications. In polycrystalline state Ni–Mn–Ga alloys show small MFIS due to grain boundary constraints. By simple size reduction of the mentioned materials it is hardly possible to create quasi-two-dimensional MFIS actuators on the microscale with a pertinent out-of-plane performance. In pursuit of the trend for next generation materials and functions by design, in the present work we have developed a laminate composite as a prototype of microactuator with the out-of-plane stroke being driven by a framework of magnetostrain responsive Ni–Mn–Ga microparticles. The laminate consisted of the layer of crystallographically oriented Ni–Mn–Ga semi-free SC microparticles sandwiched between bonding polymer and Cu foils. Such design provided a particles isolation with a minimum constraint condition from the polymer. MFIS of the individual particles and the whole laminate composite was investigated by X-ray micro-CT 3D imaging. Both particles and laminate exhibited the same recoverable out-of-plane stroke produced by the particles´ MFIS of around 3% under 0.9 T. The developed microactuator design is promising for applications in the areas of micro-robotics, optical image stabilization in cameras, pumps for microfluidics etc.

3D X-ray analysis of the subterranean burrowing depth and pupal chamber size of Laricobius (Coleoptera: Derodontidae), a specialist predator of Adelges tsugae (Hemiptera: Adelgidae).

The non-native hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), has caused a significant decline of eastern hemlock, Tsuga canadensis L. (Pinales: Pinaceae), and Carolina hemlock, Tsuga caroliniana Engelmann (Pinales: Pinaceae), in eastern North America. Biological control of HWA has focused on the use of 2 Laricobius spp. (Coleoptera: Derodontidae), natural predators of HWA, which require arboreal and subterranean life phases to complete their development. In its subterranean phase, Laricobius spp. are subject to abiotic factors including soil compaction or soil-applied insecticides used to protect hemlock from HWA. This study used 3D X-ray microcomputed tomography (micro-CT) to identify the depth at which Laricobius spp. burrows during its subterranean lifecycle, characterize pupal chamber volume, and determine whether soil compaction had a significant effect on these variables. The mean burrowing depth in the soil of individuals was 27.0 mm ± 14.8 (SD) and 11.4 mm ± 11.8 (SD) at compaction levels of 0.36 and 0.54 g/cm3, respectively. The mean pupal chamber volume was 11.15 mm3 ± 2.8 (SD) and 7.65 mm3 ± 3.5 (SD) in soil compacted at 0.36 and 0.54 g/cm3, respectively. These data show that soil compaction influences burrowing depth and pupal chamber size for Laricobius spp. This information will help us better identify the effect of soil-applied insecticide residues on estivating Laricobius spp. and soil-applied insecticide residues in the field. Additionally, these results demonstrate the utility of 3D micro-CT in assessing subterranean insect activity in future studies.