Three-dimensional Quantitative Analysis Research Articles

Aromatase as a novel target of parabens in human and rat placentas: 3D-quantitative structure-activity relationship and docking analysis

Aromatase (CYP19A1), a pivotal enzyme in the biosynthesis of estradiol from testosterone, is predominantly expressed in reproductive tissues including placentas. This study investigated the effects of paraben acid and nine parabens on the activity of human and rat CYP19A1 using microsomes derived from human and rat placentas and on estradiol secretion in human choriocarcinoma BeWo cells. The results showed that propyl, butyl, hexyl, heptyl, and nonyl parabens significantly inhibited human CYP19A1 activity, with IC50 values of 66.37, 61.08, 55.65, 48.26, and 27.24 μM, respectively. In BeWo cells, these parabens notably diminished estradiol secretion at concentrations of 100 μM. Similarly, rat CYP19A1 was inhibited by these parabens, with IC50 values of 98.07, 70.10, 41.30, 27.93, and 6.33 μM for propyl, butyl, hexyl, heptyl, and nonyl parabens, respectively. Kinetic analysis identified these compounds as mixed inhibitors. Bivariate correlation analysis revealed a negative correlation between the partition coefficient value, molecular weight, the number of carbon atoms in the alcohol moiety, as well as heavy atom number and IC50 values. Three-dimensional quantitative structure-activity relationship analysis highlighted the critical role of hydrophobic regions in determining inhibitory potency. Docking studies suggested that parabens interact with the heme-iron binding site of both human and rat CYP19A1. This study elucidates the inhibitory effects of various parabens on CYP19A1 and their binding mechanisms, thereby providing a deeper understanding of their potential impact on estrogen biosynthesis.

Three-dimensional quantitative analysis of arterial bed and elements of pelvicalyceal system of kidneys in men

The aim of the study was to investigate the patterns of three-dimensional quantitative organization of the renal artery branches in relation to the elements of the renal pelvicalyceal system in men. The study was conducted on 58 corrosion preparations of arterial vessels and renal pelvicalyceal structures obtained from men with postmortem age intervals from 22 to 75 years. As a result of the morphological study, a spatial and quantitative characteristic was given to different variants of renal artery branching, with an emphasis on their transformation into secondary vascular branches classified as zonal arteries. Additionally, a detailed analysis of the topographic and anatomical relationship between the intraorgan arterial branches of the renal artery and the excretory segments of the kidney was carried out, which made it possible to clarify the features of their spatial organization. Knowledge of the spatial arrangement of the arterial branches of the kidney, which directly correlates with the variable features of its renal pelvicalyceal apparatus and excretory system segments, opens the way to predicting potential obstacles during surgical procedures, especially during nephrolithotomy.

Dictionary Learning Method Based on K-Sparse Approximation and Orthogonal Procrustes Analysis for Reconstruction in Bioluminescence Tomography.

Bioluminescence tomography (BLT) is one kind of noninvasive optical molecular imaging technology, widely used to study molecular activities and disease progression inside live animals. By combining the optical propagation model and inversion algorithm, BLT enables three-dimensional imaging and quantitative analysis of light sources within organisms. However, challenges like light scattering and absorption in tissues, and the complexity of biological structures, significantly impact the accuracy of BLT reconstructions. Here, we propose a dictionary learning method based on K-sparse approximation and Orthogonal Procrustes analysis (KSAOPA). KSAOPA uses an iterative alternating optimization strategy, enhancing solution sparsity with k-coefficients Lipschitzian mappings for sparsity(K-LIMAPS) in the sparse coding stage, and reducing errors with Orthogonal Procrustes analysis in the dictionary update stage, leading to stable and precise reconstructions. We assessed the method performance through simulations and in vivo experiments, which showed that KSAOPA excels in localization accuracy, morphological recovery, and in vivo applicability compared to other methods.

The influence of knee position during static calibration trials on evaluation of knee loading during gait in individual with medial knee osteoarthritis

Quantitative three-dimensional gait analysis has been used to evaluate the loading at the knee (i.e. external knee adduction moment, EKAM) during level ground walking in individuals with knee osteoarthritis (OA). The magnitude of EKAM can be influenced by some factors, such as knee marker position and foot placement angles in static calibration trials, which may lead to inaccurate functional assessments and intervention planning. This study aimed to clarify the effects of knee position during static calibration trials on the evaluation of knee loading during gait in individuals with medial knee OA. Seventeen individuals with medial knee OA completed three different static standing trials; (1) knee flexed at 0 degrees, (2) knee flexed at 15 degrees, and (3) knee flexed at 30 degrees before walking at their self-selected speed. A sixteen-camera three-dimensional VICON gait analysis system with four AMTI force platforms was used to collect the EKAM, knee adduction angular impulse (KAAI), knee joint center (KJC), and other knee kinematic and kinetic variables during gait. A repeated measures ANOVA was used to investigate the differences between conditions. The 1st peak of EKAM, the 1st peak EKAM arm, KAAI, and knee extension moment were significantly increased at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). Additionally, the knee flexion moment and knee external rotation moment were significantly reduced at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). All biomechanical variables were influenced by the localization of the KJC during static calibration trials. The changes in knee position during static trials significantly affected the 1st peak EKAM, KAAI, and other knee kinematics and kinetics variables during gait. Therefore, future studies should consider keeping the participants’ knees in a consistent position during static trials between visits, as the variations in knee position could mask or exaggerate the differences between groups and interventions.

An in-situ three-dimensional study of the dynamic and mechanism during spark plasma sintering of aluminum alloys

An in-situ plasma spark sintering (SPS) apparatus, coupled with laboratory X-ray microscopy, was utilized to three-dimensionally investigate the dynamic evolution process of 7055 aluminum alloy during SPS process. The influences of sintering temperatures and particle morphology on the sintering kinetics were discussed in detail. It was observed that elevating the sintering temperatures enhanced both the rate of densification and the final compactness of the alloy. Furthermore, three-dimensional quantitative analysis of pore evolution indicated that greater discrepancies in powder size between neighboring particles facilitated pore elimination during sintering by increasing available interstitial spaces. Mechanistic analysis rationalized these observations by attributing the enhanced sintering kinetics to the greater particle size disparity, which resulted in higher necking curvature and accelerated densification. The present study therefore provides a comprehensive three-dimensional in-situ quantitative analysis on the dynamic SPS process, and is expected to advance the current comprehension of sintering mechanisms at the micron scale.

Three-Dimensional Quantitative Analysis of Internal Limiting Membrane Peeling Related Structural Changes in Retinal Detachment Repair

PurposeTo assess macular microstructural changes associated with internal limiting membrane peeling (ILMP) using three-dimensional optical coherence tomography (3D-OCT) in primary macula-off rhegmatogenous retinal detachment (RRD) repairs with vitrectomy and silicone oil (SO) tamponade. DesignRetrospective, consecutive, interventional case series. MethodsSetting: Institutional practice. Patient Population: Patients who received primary RRD repair by a single experienced surgeon between January 2017 and December 2021. Main Outcome Measures: In the qualitative comparative analysis, the presence of macular changes among patients who underwent primary RRD repair with (21 eyes) or without ILMP (20 eyes) were observed. Subsequently, a detailed quantitative analysis of ILMP-related microstructural changes in 56 eyes using both 3D and 2D-OCT images were performed. ResultsIn the qualitative comparative analysis, macular microstructural changes were observed in 95% of ILMP eyes and 5% of non-ILMP eyes (p < 0.001). In the quantitative analysis, four major macular microstructural changes were detected: dimple (75%), dissociated nerve fiber layer (DONFL) (55%), ILM peeling edge thinning (IPET) (64%), and temporal macular groove (TMG) (23%). Dimples (n = 251, average 4.5 ± 5.8 per eye) could be further classified into type I (confined to the inner plexiform layer [IPL]; 73%) and type II (beyond IPL, 27%). The average depth of the deepest dimples was 58 ± 18 μm. The extent of IPET was 6.0 ± 3.7 clock hours. The average length of TMG was 1.8 ± 0.4 mm. Comparing to unoperated fellow eyes, the eyes after ILMP showed decreased inner temporal over nasal retinal thickness ratio (0.86 ± 0.07 versus 0.96 ± 0.03, p < 0.001), shorter disc-fovea distance (4.61 ± 0.32 µm versus 4.78 ± 0.37 µm, p = 0.041), and wider retinal vein trajectories (c’ = 2.48 ± 0.84 versus 3.39 ± 1.61, p = 0.002). ConclusionsMacular microstructural changes are common after ILMP in RRD repair, encompassing both focal changes (dimples, DONFL) and zonal changes (IPET, TMG). DONFL and dimples may be part of a continuum of findings stemming from the same mechanism. IPET and TMG are the results of macular tissue shift due to contracture of the optic disc and neurovascular bundle.

Quantitative Three-Dimensional Imaging Analysis of HfO2 Nanoparticles in Single Cells via Deep Learning Aided X-ray Nano-Computed Tomography.

It is crucial for understanding mechanisms of drug action to quantify the three-dimensional (3D) drug distribution within a single cell at nanoscale resolution. Yet it remains a great challenge due to limited lateral resolution, detection sensitivities, and reconstruction problems. The preferable method is using X-ray nano-computed tomography (Nano-CT) to observe and analyze drug distribution within cells, but it is time-consuming, requiring specialized expertise, and often subjective, particularly with ultrasmall metal nanoparticles (NPs). Furthermore, the accuracy of batch data analysis through conventional processing methods remains uncertain. In this study, we used radioenhancer ultrasmall HfO2 nanoparticles as a model to develop a modular and automated deep learning aided Nano-CT method for the localization quantitative analysis of ultrasmall metal NPs uptake in cancer cells. We have established an ultrasmall objects segmentation method for 3D Nano-CT images in single cells, which can highly sensitively analyze minute NPs and even ultrasmall NPs in single cells. We also constructed a localization quantitative analysis method, which may accurately segment the intracellularly bioavailable particles from those of the extracellular space and intracellular components and NPs. The high bioavailability of HfO2 NPs in tumor cells from deeper penetration in tumor tissue and higher tumor intracellular uptake provide mechanistic insight into HfO2 NPs as advanced radioenhancers in the combination of quantitative subcellular image analysis with the therapeutic effects of NPs on 3D tumor spheroids and breast cancer. Our findings unveil the substantial uptake rate and subcellular quantification of HfO2 NPs by the human breast cancer cell line (MCF-7). This revelation explicates the notable efficacy and safety profile of HfO2 NPs in tumor treatment. These findings demonstrate that this 3D imaging technique promoted by the deep learning algorithm has the potential to provide localization quantitative information about the 3D distributions of specific molecules at the nanoscale level. This study provides an approach for exploring the subcellular quantitative analysis of NPs in single cells, offering a valuable quantitative imaging tool for minute amounts or ultrasmall NPs.

Three-dimensional quantitative study and functional outcome analysis of coronoid fracture in different elbow injury patterns

BackgroundCoronoid fractures are often part of a complex fracture-dislocation of the elbow. For an optimum prognosis, it is important to understand the characteristics of coronoid fractures in different elbow injury patterns. Significant differences in these characteristics have been observed in various studies, but these previous studies have suffered from limitations, such as insufficient quantification and unknown prognostic differences among different injury patterns. Therefore, we aimed to quantitatively analyze coronoid fracture characteristics and functional outcomes in different elbow injury patterns using 3D-CT. MethodsAll patients with coronoid fractures surgically treated at our hospital between January and December 2017 were categorized into three groups according to elbow injury pattern: PLRI, VPMRI and OFD. 3D models were reconstructed using Mimics 17.0, and the total volume (TV) and number of coronoid fragments (NCF) were measured. The coronoid process edge was classified into different anatomical regions, and each region was assigned a number to quantify the distribution of fracture lines. At the last follow-up, the ROM, VAS, MEPS, complications and reoperations were recorded. ResultsThe ninety-two patients enrolled had an average age of 42±15 years and a male-to-female ratio of 66:26. The median TV in PLRI patients was less than that in VPMRI patients [431 (132, 818)mm3 vs. 1125 (746,1421)mm3,adjusted P<0.001] and OFD patients [431 (132, 818) mm3 vs. 2565 (381, 4076)mm3, adjusted P =0.001]. The median NCF in PLRI patients was also less than that in VPMRI patients [1 (1, 2) vs. 2 (1, 3), adjusted P=0.043]. Most of the PCFL-Rs (79%) were located around the volar edge of the lesser sigmoid notch. Compared with that of PLRI, the PCFL-Us of the VPMRI and OFD tended to be located on the more ulnodorsal side of the coronoid process edge. The median ROM [110 (90, 133), P=0.001] and the median MEPS [85 (68, 95), P=0.038] of patients with OFD were significantly less than those of patients with the other two patterns. The incidence of elbow stiffness (56%, 5/9, P=0.001) and implant-related irritation (44%, 4/9, P<0.001) in the OFD group was significantly higher than that in the other two groups. ConclusionCoronoid fractures differ significantly in fragment volume, comminution severity and fracture line distribution among different elbow injury patterns. OFD has the worst functional outcomes among complex elbow injury patterns.

Label-free three-dimensional imaging and quantitative analysis of living fibroblasts and myofibroblasts by holotomographic microscopy.

Holotomography (HT) is a cutting-edge fast live-cell quantitative label-free imaging technique. Based on the principle of quantitative phase imaging, it combines holography and tomography to record a three-dimensional map of the refractive index, used as intrinsic optical and quantitative imaging contrast parameter of biological samples, at a sub-micrometer spatial resolution. In this study HT has been employed for the first time to analyze the changes of fibroblasts differentiating towards myofibroblasts - recognized as the main cell player of fibrosis - when cultured in vitro with the pro-fibrotic factor, namely transforming growth factor-β1. In parallel, F-actin, vinculin, α-smooth muscle actin, phospho-myosin light chain 2, type-1 collagen, peroxisome proliferator-activated receptor-gamma coactivator-1α expression and mitochondria were evaluated by confocal laser scanning microscopy. Plasmamembrane passive properties and transient receptor potential canonical channels' currents were also recorded by whole-cell patch-clamp. The fluorescence images and electrophysiological results have been compared to the data obtained by HT and their congruence has been discussed. HT turned out to be a valid approach to morphologically distinguish fibroblasts from well differentiated myofibroblasts while obtaining objective measures concerning volume, surface area, projection area, surface index and dry mass (i.e., the mass of the non-aqueous content inside the cell including proteins and subcellular organelles) of the entire cell, nuclei and nucleoli with the major advantage to monitor outer and inner features in living cells in a non-invasive, rapid and label-free approach. HT might open up new research opportunities in the field of fibrotic diseases. RESEARCH HIGHLIGHTS: Holotomography (HT) is a label-free laser interferometric imaging technology exploiting the intrinsic optical property of cells namely refractive index (RI) to enable a direct imaging and analysis of whole cells or intracellular organelles. HT turned out a valid approach to distinguish morphological features of living unlabeled fibroblasts from differentiated myofibroblasts. HT provided quantitative information concerning volume, surface area, projection area, surface index and dry mass of the entire fibroblasts/myofibroblasts, nuclei and nucleoli.

Age and anatomical region-related differences in vascularization of the porcine meniscus using microcomputed tomography imaging.

Meniscal lesions in vascularized regions are known to regenerate while lack of vascular supply leads to poor healing. Here, we developed and validated a novel methodology for three-dimensional structural analysis of meniscal vascular structures with high-resolution microcomputed tomography (µCT). We collected porcine medial menisci from 10 neonatal (not-developed meniscus, n-) and 10 adults (fully developed meniscus, a-). The menisci were cut into anatomical regions (anterior horn (n-AH anda-AH), central body (n-CB anda-CB), and posterior horn (n-PH anda-PH). Specimens were cut in half, fixed, and one specimen underwent critical point drying and µCT imaging, while other specimen underwent immunohistochemistry and vascularity biomarker CD31 staining for validation of µCT. Parameters describing vascular structures were calculated from µCT. The vascular network in neonatal spread throughout meniscus, while in adult was limited to a few vessels in outer region, mostly on femoral side. n-AH, n-CB, and n-PH had 20, 17, and 11 times greater vascular volume fraction than adult, respectively. Moreover, thickness of blood vessels, in three regions, was six times higher in adults than in neonatal. a-PH appeared to have higher vascular fraction, longer and thicker blood vessels than both a-AH and a-CB. Overall, neonatal regions had a higher number of blood vessels, more branching, and higher tortuosity compared to adult regions. For the first time, critical point drying-based µCT imaging allowed detailed three-dimensional visualization and quantitative analysis of vascularized meniscal structures. We showed more vascularity in neonatal menisci, while adult menisci had fewer and thicker vascularity especially limited to the femoral surface.

129 Neuroimaging Analysis of Bilateral Thalamic Delivery for Gene Therapy

INTRODUCTION: Axonal transport from the thalamus (an integrative hub for the entire cortex) has been shown to facilitate widespread gene/protein delivery. Here, we report our neuroimaging experience with bilateral thalamic convection-enhanced delivery of adeno-associated virus (AAV) vectors for GM2 gangliosidoses. METHODS: Magnetic resonance imaging (MRI) of eight pediatric patients who underwent bilateral thalamic HEXA/HEXB delivery were retrospectively reviewed. Quantitative three-dimensional volumetric analyses of MRI thalamic signals were used to establish volume of distribution (Vd) versus volume of infusion (Vi). The distance of cannula placement within the thalamus was calculated and validated using the numbers used in the intraoperative ROSA robotic software. Backflow and leakage into surrounding structures were also analyzed. RESULTS: Fourteen thalamic injection volumes were considered in the final analysis. Calculated volume of thalamic infusate signal was up to 43.8% (mean = 21.3±13.3) of the thalamic volume. The Vd/Vi ratio ranged from 0.4-2.7 (mean = 1.9±0.7), depending on infusate volume. Diffusate shape was round to slightly ellipsoid in all patients. Backflow and leakage were encountered in 14.3% and 12.5%, respectively, of thalamic injections. CONCLUSIONS: This study provides the first in-human quantitative MRI data for intrathalamic infusion. The ideal location for the cannula tip was determined to be between the mediodorsal and lateral dorsal nuclei and the ideal trajectory keeps all of the cannula steps within the thalamic boundaries. We also compare these data to published NHP and our own NHP and sheep data. Overall, the Vd/Vi ratios are lower in human subjects (∼2) than in animal subjects (∼3). We hypothesize that this may be due in part to species specific differences in displacement of extracellular fluid versus infusion volume.

Three-dimensional qualitative and quantitative analysis of mouse corneal nerve

Three-dimensional qualitative and quantitative analysis of mouse corneal nerve

Effects of microbubble pretreatment on physiochemical and microbial properties of excess activated sludge.

Fast increased amount of excess activated sludge (EAS) from wastewater treatment plants has aroused universal concerns on its environmental risks and demands for appropriate treatments, while effective treatment is dependent upon proper pretreatment. In this study, air-supplied microbubbles (air-MBs) with generated size of 25.18 to 28.25 μm were used for EAS pretreatment. Different durations (30, 60, 90, and 120 s) yielded sludge with varied physiochemical conditions, and 60 s decreased sludge oxidation status and significantly increased adenosine triphosphate (ATP) content. Soluble, loosely-bound, and tightly-bound extracellular polymeric substances (SEPS, LB-EPS, and TB-EPS) were extracted from the sludge through a stepwise approach and examined through three-dimensional excitation-emission matrix (3D-EEM) and quantitative analysis. The results showed that 60- and 120-s treatments generated stronger fluorescence intensities on dissolved organic matters (DOMs) of protein-like and fulvic acid in LB-EPS and TB-EPS, which indicated the decrease of counterparts in EAS, and therefore facilitated sludge dewaterability and reduction. The dominant microbial communities in EAS, including Proteobacteria, Bacteroidota, Chloroflexi, and Actinobacteriota, were not significantly affected by MB pretreatment. The results collectively revealed the effects of MB pretreatment on EAS and indicated that MBs could be an effective pretreatment technique for EAS treatment process.

3D-QSAR Studies on High-affinity Phosphodiestera.

Recent studies have found that Phosphodiesterase-4 (PDE4) is closely related to the pathogenesis of depression, cognitive impairment and neurological impairment. Our objective is to develop potent inhibitors of the high-affinity phosphodiesterase 4D isoform (PDE4D) that can serve as radioligands for Positron Emission Tomography (PET) imaging, thereby advancing research in the field of neurological diseases. We employed a multi-step approach combining three-dimensional quantitative structure-activity relationship (3D-QSAR) modeling, molecular docking, classification techniques, and CoMSIA analysis to investigate the conformational relationship of highaffinity PDE4D inhibitors as PET ligands. ADMET and Drug-likeness predictions were also conducted. By utilizing these methods, our aim was to identify more potent PDE4D inhibitors. The results showed that the CoMSIA model with the best principal component scores (n=7) had a cross-validated Q2 value of 0.602 and a non-cross-validated R2 value of 0.976. These results affirmed the excellent predictive capability of the established CoMSIA model. Analysis of the generated 3D-QSAR contour plots highlighted specific regions in the molecular structure of the compounds that can be further optimized and modified. Guided by the contour plots, we designed 100 novel PDE4D inhibitors, and molecular docking was performed for the top 4 compounds with high activity. The molecular docking scores were promising, and ADMET and drug similarity predictions yielded satisfactory results. Taking into consideration these factors, compound 51c was determined to be the optimal compound, laying a solid foundation for further research. For the continued development of PDE4D PET radioligand, these models and new compounds' developing methodology offer a theoretical foundation and crucial references.

Highly efficient, coke-free electrolysis of dry CO2 in solid oxide electrolysis cells

Dry CO2 electrolysis in solid oxide electrolysis cells (SOECs), a highly efficient, versatile method for converting CO2 into value-added products, is critically limited by carbon deposition on Ni-based fuel electrodes. We achieved efficient, coke-free CO2 electrolysis using SOECs by elaborately controlling the local gas environments. Multilayered electrode microstructures were systematically engineered to facilitate mass transport and maintain the CO partial pressure below the threshold for solid carbon formation. A fuel-electrode-supported cell with an improved electrode microstructure operated stably for 500 h without coking at 0.50 A cm−2 and 700 °C, whereas conventional ones failed immediately. Multiphysics modeling coupled with three-dimensional quantitative microstructural analysis confirmed our improved electrode successfully mitigated carbon deposition. Furthermore, the enhanced electrode substantially lowered the overpotential and increased the CO production rate by > 50 %. These results highlight the feasibility of coke-free dry CO2 electrolysis in SOECs using commercially viable materials by controlling the electrode transport properties.

Coronary Artery Bypass Graft Effect on Cardiogoniometry Characteristic in Patients with Coronary Heart Disease

Abstract Context: Cardiogoniometry (CGM) is a noninvasive technique for quantitative three-dimensional vectorial analysis of myocardial depolarization and repolarization. We describe a method of surface electrophysiological cardiac assessment using CGM performed at rest to detect variables helpful in identifying coronary artery disease (CAD) and interplaying factors in patients who underwent coronary artery bypass graft (CABG). Materials and Methods: In this study, all patients with CAD undergoing CABG were enrolled. Echocardiography, CGM, and electrocardiography (ECG) were obtained before surgery and a month later. The ECG and CGM alterations were compared before and after CABG and the accuracy of those two methods was evaluated. Results: In this study, 50 patients were enrolled, of which 33 (66%) were male versus 17 (44%) female, with a mean age of 39.12 ± 60 years. The mean ejection fraction before and after surgery was 44.3 ± 7.9% (range: 20–55) and 40.9 ± 12.5% (20–50), respectively. Before surgery, all patients had sinus rhythm, five cases had left bundle-branch block (LBBB), and one case was with right bundle-branch block (RBBB). Subsequently, after surgery, five cases had LBBB, and two cases were found to have RBBB. The rate of postoperation bleeding was 20%. There was no significant change in echocardiographic characteristics before and after operation (P = 0.81); likewise, no significant change was seen in ECG criteria before and after operation (P = 0.96). A significant correlation was seen regarding CGM characteristics before and after CABG (P = 0.003). Conclusions: A significant association was seen regarding CGM characteristics before and after undergoing an operation. In addition, the specificity and sensitivity of the CGM and ECG before and after operation improved well.

Three-dimensional quantitative analysis of porosity evolution and inheritance from biomass to biochar through pyrolysis

Electron tomography is employed to conduct a comprehensive porosity analysis of the biomass tobacco and its derived carbon materials.

Overcoming strength-ductility trade-off by building a micro-nano laminated structure based on an ultralow amount of single-dispersed carbon nanotubes

CNTs/Ti composites (Carbon nanotube reinforced titanium matrix composites) with a novel micro-nano laminated structure consisting of alternating CNTs nanolayers and Ti microlayers were successfully prepared by electrophoretic deposition combined with spark plasma sintering and temperature-controlled rolling. The CNTs/Ti composites exhibited a simultaneous enhancement in both strength and ductility compared to pure Ti fabricated by the same methods, despite the addition of CNTs being an ultra-low 0.02 weight percent (wt.%). The improvement in strength was attributed to (i) the high strengthening efficiency of individually dispersed, structurally intact CNTs and (ii) Heterogeneous deformation-induced (HDI) strengthening resulting from the heterogeneous deformation between soft Ti microlayers and hard CNTs nanolayers. Furthermore, the HDI hardening induced by the micro-nano laminated structure led to extra work hardening, enhancing the uniform deformability of CNTs/Ti composites. Consequently, strain localization was suppressed, as observed by in-situ tensile experiments, thereby preventing the initiation of interfacial. Additionally, interfacial crack propagation was significantly delayed due to CNTs bridging and crack tip blunting by ductile Ti microlayers, thereby promoting the total elongation to failure. Moreover, a progressive fracture process consisting of three stages was proposed, based on three-dimensional visualization and quantitative analysis of crack volumes. This provided a new strategy for overcoming the strength-ductility trade-off of traditional metal (Ti, Al, Fe, Ni, etc.) matrix composites through the reasonable design of a hierarchical architecture based on an ultra-low amount of high-quality nanoscaled reinforcements.

INFLUENCE OF FEMUR LENGTH ON ASYMMETRY OF PROSTHETIC GAIT BIOMECHANICS IN TRANSFEMORAL AMPUTATION

This study compares the prosthetic gait asymmetry in transfemoral amputees with varied femoral lengths to able-bodied participants in terms of temporal-spatial parameters and joint kinematics. Sixteen young and active transfemoral amputees with short and long residual limbs were divided into two groups and subjected to three-dimensional quantitative motion analysis through high definition optoelectronic cameras and force platform. The prosthetic gait of amputees was compared with those of 15 participants with normal gait to analyze the asymmetry. There was a significant difference in temporal-spatial gait parameters between the amputee groups in terms of intact limb stride length and swing time ([Formula: see text]). The gait of amputees with long femoral lengths was with comparatively higher mean step length (0.31 versus 0.35[Formula: see text]m), velocity (0.48 versus 0.44[Formula: see text]m/s), and cadence (73.58 versus 66.62 steps/min) compared to short residual limbs, however these results are nonsignificant ([Formula: see text]). Amputees and able-bodied participants differed significantly for all measured parameters ([Formula: see text]). The amputees with short residual limbs had more variation in sagittal plane hip flexion at initial contact than long amputees and able-bodied subjects. Amputees with longer residual limbs demonstrated peak swing prosthetic hip flexion closer to able-bodied individuals. The frontal pelvic obliquity and sagittal pelvic tilt revealed more variance among amputees with shorter residual limbs than longer ones. This study will aid in identifying the underlying mechanism of gait asymmetry in transfemoral amputees in relation to residual femoral length and hence will pave a path for improving the knee and foot prosthetic components.

Quantitative three-dimensional local order analysis of nanomaterials through electron diffraction

Structure-property relationships in ordered materials have long been a core principle in materials design. However, the introduction of disorder into materials provides structural flexibility and thus access to material properties that are not attainable in conventional, ordered materials. To understand disorder-property relationships, the disorder – i.e., the local ordering principles – must be quantified. Local order can be probed experimentally by diffuse scattering. The analysis is notoriously difficult, especially if only powder samples are available. Here, we combine the advantages of three-dimensional electron diffraction – a method that allows single crystal diffraction measurements on sub-micron sized crystals – and three-dimensional difference pair distribution function analysis (3D-ΔPDF) to address this problem. In this work, we compare the 3D-ΔPDF from electron diffraction data with those obtained from neutron and x-ray experiments of yttria-stabilized zirconia (Zr0.82Y0.18O1.91) and demonstrate the reliability of the proposed approach.