Average Shape Research Articles

Internally-consistent and fully-unbiased multimodal MRI brain template construction from UK Biobank: Oxford-MM

Abstract Anatomical MRI templates of the brain are essential to group-level analyses and image processing pipelines, as they provide a reference space for spatial normalisation. While it has become common for studies to acquire multimodal MRI data, many templates are still limited to one type of modality, usually either scalar or tensor-based. Aligning each modality in isolation does not take full advantage of the available complementary information, such as strong contrast between tissue types in structural images, or axonal organisation in the white matter in diffusion tensor images. Most existing strategies for multimodal template construction either do not use all modalities of interest to inform the template construction process, or do not use them in a unified framework. Here, we present multimodal, cross-sectional templates constructed from UK Biobank data: the OMM-1 template, and age-dependent templates for each year of life between 45 to 81. All templates are fully unbiased to represent the average shape of the populations they were constructed from, and internally consistent through jointly informing the template construction process with T1, T2-FLAIR and DTI data. The OMM-1 template was constructed with a multi-resolution, iterative approach using 240 individuals in the 50-55 year age range. The age-dependent templates were estimated using a Gaussian Process, which describes the change in average brain shape with age in 37,330 individuals. All templates show excellent contrast and alignment within and between modalities. The global brain shape and size is not preconditioned on existing templates, although maximal possible compatibility with MNI-152 space was maintained through rigid alignment. We showed benefits in registration accuracy across two datasets (UK Biobank and HCP), when using the OMM-1 as the template compared with FSL’s MNI-152 template, and found that the use of age-dependent templates further improved accuracy to a small but detectable extent. All templates are publicly available and can be used as a new reference space for uni- or multimodal spatial alignment.

Continuous wave laser ablation for tailored titanium nanoparticle synthesis: temperature and liquid medium effects

We reported for the first time the generation of titanium (Ti) nanoparticles (NPs) in different liquids (deionized (DI) water and sodium dodecyl sulfate (SDS) solution) and at a range of temperatures (5 °C, 28 °C, 60 °C, and 80 °C) using continuous-wave high-power laser ablation in liquid (CWLAL). The CWLAL technique is a convenient and cost-effective way to generate NPs. The key outcomes of our investigation are the effects of temperature and the liquid mediums on the average size, generation rate, shape, surface charges, and crystallographic structure of the NPs. Generated NPs show consistent spherical shape regardless of liquid medium changes and temperature variation. SDS solution notably impacts NP size and generation rate with higher surface charges than DI water. For instance, at temperatures of 28 °C and 80 °C, the generation rates in SDS solution are 316 mg/hr and 309 mg/hr, with average NP sizes of 33 nm and 34 nm, respectively. In contrast, the generation rates in DI water are 96 mg/hr and 302 mg/hr, with NP sizes of 13 nm and 20 nm, respectively. The weaker crystallographic structure observed in NPs generated in SDS solution, compared to the more robust crystallographic structure of NPs synthesized in DI water. Liquid temperature plays a significant role in determining surface charges, average particle size, and molecular structure of NPs. The choice of the liquid medium and temperature can be critical for tailoring NP characteristics to specific applications. Ongoing work is being conducted to explore the possibilities of further progress in this area to generate efficient and customized NPs.

Is LCZ Enough? Physical Properties, Thermal Environments and Cooling Effects of Green Roofs in High-Density Urban Industrial Blocks

With rapid worldwide urbanization, the urban heat island (UHI) effect is becoming more and more serious. The UHI effect is more intense in industrial areas. Green roofs are an effective way to mitigate UHIs in high-density cities, which calls for thorough examination. This study explored the associations between the block characteristics and block thermal environment in high-density industrial areas based on the widely accepted Local Climate Zone (LCZ) scheme. The pedestrian air temperature comparisons before and after virtual green roof installations presented the cooling effects of green roofs. Thirty-six typical industrial blocks were involved in the study and the simulations were conducted utilizing ENVI-met. The results showed that (1) the air temperature in LCZ4 is significantly lower than those in LCZ2 and LCZ6, but no significant differences were identified between other pairs of LCZ types; (2) the cooling effect of green roofs significantly differs among LCZs, and is associated with sky view factor (SVF), average building area (ABA) and average building shape index (ABSI); (3) in high-density urban areas, additional functional parameters and building-volume indices should be included to better address the physical characteristics, thermal environment, and green roof cooling effect of industrial blocks. This study could improve the validity of LCZ classification for high-density industrial blocks and may provide direct implications for green roof planning.

Blue Laser for Production of Carbon Dots.

The synthesis of carbon dots (CDs) is gaining wide-ranging interest due to their broad applicability, owing to their small size and luminescence. CDs were prepared from charcoal via a one-step process using laser ablation in liquid without the use of reagents. The adopted method was based on the use of a commercially available continuous wave (CW) laser diode emitting a 450 nm wavelength and, for the liquid, a phosphate-buffered saline (PBS) solution, routinely used in the biological field. Photoluminescence analysis revealed fluorescence, at 480 nm, increasing with laser irradiation time. The atomic force microscopy (AFM) of the CDs revealed an average sphere shape with a size of about 10 nm. Biodegradable polycaprolactone (PCL), typically adopted in biomedicine applications, was used as a matrix to show the preserved luminescence, ideal for the non-invasive monitoring of implanted scaffolds in tissue engineering.

Statistics of unidirectional wave groups with and without freak waves observed in the Norwegian Sea

The statistical properties of observed wave groups are essential for designing marine structures. However, the characteristics of group energy, length, and profiles remain unclear. This paper analyzes more than 1 million measured ocean unidirectional wave groups in deep water of the Norwegian Sea during a decade. By classifying wave groups into ordinary and extreme categories based on the presence of a freak wave, it is found that both the distributions of the non-dimensional group energy and group duration follow the Generalized extreme value functions. Moreover, the statistics of wave groups are significantly influenced by the spectral width, with wave steepness having negligible effects. The ratio of the average group duration between extreme and ordinary categories varies slightly from 1.4 to 1.8, although the energy of extreme wave groups can reach 3.0–4.5 times than that of ordinary wave groups. Furthermore, unlike the typical shape of a freak wave with a high wave crest or deep wave trough significantly larger than the surrounding waves, consecutive large waves resembling the “three sisters” are quite common in this location. However, NewWave theory generally underestimates the wave amplitudes surrounding a freak wave, leading to the predicted energy of the most likely extreme wave groups being only about 50–80% of the measured values. Finally, a new modified model is proposed to predict the average shapes of extreme wave groups. After testing numerous wave cases, the model accurately captures the mean morphology of extreme wave groups in the Norwegian Sea.

Self-Healable, Transparent, Biodegradable, and Shape Memorable Polyurethanes Derived from Carbon Dioxide-Based Diols.

A series of CO2-based thermoplastic polyurethanes (TPUs) were prepared using CO2-based poly(polycarbonate) diol (PPCDL), 4,4'-methylenebis (cyclohexyl isocyanate) (HMDI), and polypropylene glycol (PPG and 1,4-butanediol (BDO) as the raw materials. The mechanical, thermal, optical, and barrier properties shape memory behaviors, while biocompatibility and degradation behaviors of the CO2-based TPUs are also systematically investigated. All the synthesized TPUs are highly transparent amorphous polymers, with one glass transition temperature at ~15-45 °C varying with hard segment content and soft segment composition. When PPG is incorporated into the soft segments, the resultant TPUs exhibit excellent self-healing and shape memory performances with the average shape fixity ratio and shape recovery ratio as high as 98.9% and 88.3%, respectively. Furthermore, the CO2-based TPUs also show superior water vapor permeability resistance, good biocompatibility, and good biodegradation properties, demonstrating their pretty competitive potential in the polyurethane industry applications.

Genetic Diversity and Response of Melon Accessions toMonosporascus cannonballus

ABSTRACTMelon holds significant economic importance for Brazilian agribusiness. It exhibits high polymorphism and genetic variability, yet knowledge regarding its genetic diversity and response to root diseases remains limited. Therefore, this study aimed to assess the genetic diversity and response of melon plant accessions to Monosporascus cannonballus. Two trials were conducted involving 29 melon accessions and a commercial hybrid of the yellow melon plant, Natal RZ. In the first trial, the accessions and the commercial hybrid were grown in the field under a randomised complete block design with three replications. They were evaluated for fruit‐related descriptors: number of fruits per plant (NFP), average fruit weight, shape index, pulp thickness, pulp firmness (PF) and total soluble solids (TSS). Standardised Euclidean distances were calculated on the basis of the results, and the accessions were grouped using the UPGMA method. In the second trial, the melon plant accessions and commercial hybrid were cultivated in a greenhouse under a completely randomised design with 12 replications. For inoculation, wheat grains infested with M. cannonballus isolate CMM‐2429 were used. Evaluations were conducted 60 days after transplanting, assessing the incidence and severity of the disease, and biometric variables. The study revealed genetic variability among the evaluated accessions for fruit descriptors and response to M. cannonballus. Most divergent accessions were A16, A53, NZR, A28, A51 and A44, with divergence primarily observed in NFP, PF and TSS. Promising accessions for breeding programmes aimed at resistance to M. cannonballus included A01, A04, A25, A27 (moderately resistant) and A26 (highly resistant to the pathogen).

The Concept of Ideal Lips of Caucasian Female: An Anthropometric Analysis of the Lower Third of the Face.

The demand for lip-redefining procedures has been rising in recent years, thus creating the need for reliable and detailed reference sources on aesthetic female lips. This study investigates the morphology of the lower third of the face, including the lips and jawline, of attractive young Caucasian females. A semi-automatic photogrammetric analysis of the faces of professional female photograph models (n=400) of the Caucasian race aged 18-39 was performed. Angular, linear, and surface area parameters were evaluated. A graphical summarization of the average facial shape of all analyzed attractive females was generated as an average body contours (ABC) image. The height of the lower third of the face equaled 0.32 ± 0.02 of the total facial height. The average lip width was 48.06 ± 3.34mm. The upper vermilion height was found to be significantly lower than the lower vermilion height (6.47 ± 1.36 vs. 11.64 ± 1.46mm, p < 0.01). The lip obliquity angle was found to be 1.05° ± 0.79°. The area surface of the upper lip vermilion was considerably smaller than the vermilion of the lower lip (p < 0.01). This is one of the largest studies on attractive Caucasian females' lips and lower face morphology. The data it provides, including the graphical presentation of the aesthetic lower face as an ABC image, may provide physicians with valuable guidelines for lips rejuvenation and reconstruction procedures. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Unravelling the nexus between structure, texture, and acoustic traits of fried chicken nuggets

SummaryTexture is a multi‐parameter attribute and one of the prime quality attributes of fried products. This study explored the nexus between microstructure and texture of fried breaded chicken nuggets. Chicken nuggets were deep‐fat fried (2, 4, 6, and 8 min) in canola oil at different frying temperature (170, 180, and 190 °C). Microstructure and texture of fried samples were assessed by scanning electron microscopy (SEM) and acoustic‐mechanical texture analyser, respectively. Maximum force (Fmax), number of force peaks (NFP), area under force‐deformation plots (FA), sound pressure level (SPL), number of sound peaks (AUX), and area under amplitude‐time curves (SA) were used to describe the textural parameters. Microstructural indices (porosity, number of pores, average pore area, polydispersity index, and average shape factor) were estimated from the SEM images. Results revealed that, both the frying time and temperature were positively correlated with the mechanical (Fmax: 25–55 N, NFP: 05–74 N, FA: 6500–15 000 N.sec) and acoustic (SPL: 88–97 dB, AUX: 650–810 dB, SA: 380–405 dB.sec) parameters. Frying time and temperature significantly (P &lt; 0.05) impacted the formation of micropores in fried chicken nuggets. Crust microporosity showed strong positive correlations (r = 0.82) with the AUX value. The NFP, SPL, and SA of the fried nuggets were significantly (P &lt; 0.05) impacted by the crust microporosity. Crust porosity (10–30%), number of pores (8–400), average pore area (10–4000 μm2), polydispersity index (0.05–0.2), and average shape factor (0.8–1.1) of fried nuggets were significantly (P &lt; 0.05) influenced by both the frying time and temperature. Findings from this study would be useful in quality improvement and process monitoring including modelling of coated fried products.

Multivariable model for gait pattern differentiation in elderly patients with hip and knee osteoarthritis: A wearable sensor approach

BackgroundHip and knee osteoarthritis (OA) patients demonstrate distinct gait patterns, yet detecting subtle abnormalities with wearable sensors remains uncertain. This study aimed to assess a predictive model's efficacy in distinguishing between hip and knee OA gait patterns using accelerometer data. MethodParticipants with hip or knee OA underwent overground walking assessments, recording lower limb accelerations for subsequent time and frequency domain analyses. Logistic regression with regularization identified associations between frequency domain features of acceleration signals and OA, and k-nearest neighbor classification distinguished knee and hip OA based on selected acceleration signal features. FindingsWe included 57 knee OA patients (30 females, median age 68 [range 49–89], median BMI 29.7 [range 21.0–45.9]) and 42 hip OA patients (19 females, median age 70 [range 47–89], median BMI 28.3 [range 20.4–37.2]). No significant difference could be found in the time domain's averaged shape of acceleration signals. However, in the frequency domain, five selected features showed a diagnostic ability to differentiate between knee and hip OA. Using these features, a model achieved a 77 % accuracy in classifying gait cycles into hip or knee OA groups, with average precision, recall, and F1 score of 77 %, 76 %, and 78 %, respectively. InterpretationThe study demonstrates the effectiveness of wearable sensors in differentiating gait patterns between individuals with hip and knee OA, specifically in the frequency domain. The results highlights the promising potential of wearable sensors and advanced signal processing techniques for objective assessment of OA in clinical settings.

The impact of crystal grain size on the behavior of disordered ferromagnetic systems: from thin to bulk geometry

We report the findings of an extensive and systematic study on the effect of crystal grain size on the response of field-driven disordered ferromagnetic systems with thin, intermediate, and bulk geometry. For numerical modeling we used the athermal nonequilibrium variant of the random field Ising model simulating the systems with tightly packed and uniformly cubic-shaped, magnetically exchange-coupled crystal grains, conducted over a wide range of grain sizes. Together with the standard hysteresis loop characterizations, we offer an in-depth examination of the avalanching response of the system, estimating the effective grain-size-related exponents by analyses of the distributions of various avalanche parameters, average avalanche shape and size, and power spectra. Our results demonstrate that grain size plays an important role in the behavior of the system, outweighing the effect of its geometry. For sufficiently small grains, the characteristics of the system response are largely unaffected by grain size; however, for larger grains, the effects become more noticeable and show up as distinct asymmetry in the magnetization susceptibilities and average avalanche shapes, as well as characteristic kinks in the distributions of avalanche parameters, susceptibilities, and magnetizations for the largest grain sizes. Our insights, unveiling the sensitivity of the system’s response to the underlying structure in terms of crystal grain size, may prove beneficial in interpreting and analyzing experimental results obtained from driven disordered ferromagnetic samples of different geometries, as well as in extending the range of possible applications.

Variation in Lip Shape and Aesthetics in the Young Female Population: A Statistical Atlas Study.

Background: The distribution of lip shapes in young females and how morphological variation relates to attractiveness are poorly defined. Objectives: We hypothesized that among young female lip images generated by a statistical atlas model, those with more full lips compared with those with less full lips would be perceived as more attractive as measured by anonymous survey participants. Method: A statistical atlas of lip morphology was created using photographs of 700 women aged 18-35 years. The average lip shape was determined by coregistering and averaging images. Morphological variation was analyzed using principal component analysis. The relationship between attractiveness and observed lip morphologies was assessed using publicly distributed surveys. Results: In total, 428 survey responses were obtained. We developed a statistical model of variation of lip shape in the population and its relationship to attractiveness. The most attractive lips were significantly fuller than the average shape in the population, with greater vertical height and surface area. Conclusion: A statistical atlas can provide a visual guide to variation in lip shape in the population. The most attractive lip shapes vary significantly from the population average, lending support to procedures that increase lip height and surface area.

Disintegration characteristics and mechanism of red clay improved by steel slag powder

Red clay is prone to softening and disintegration when exposed to water, often triggering severe geological disasters. To enhance its resistance to disintegration, this paper employs a homemade wet-dry cycling disintegration apparatus, combined with XRD, SEM, MIP, and fractal theory, to analyze the effects of different activators on the disintegration characteristics and microscopic mechanisms of SSP-improved soil. Under wet-dry cycling, the disintegration process of SSP-improved soil can be divided into five stages: rapid water absorption, saturation wetting, rapid disintegration, softening and dissolution, and stable non-disintegration. As the activator and SSP content increase, the resistance to disintegration of SSP-improved soil gradually enhances. After the addition of activators, the porosity, pore area, pore length and width, and probability entropy of SSP-improved soil decrease (i.e., 7 % NS < 7 % CSW < 7 % NH < undisturbed soil), while the average shape factor, regional probability distribution index, and fractal dimension increase. This is because activators promote ion exchange, cementation, crystallization, and carbonation reactions in SSP-improved soil, generating a substantial amount of hydration products such as C-S(A)-H, Ca(OH)2 and CaCO3, which fill and encapsulate inter-particle pores, thereby reducing water flow channels within the pores. In contrast, the pore structure between particles in undisturbed soil is simple and well-connected, providing favorable conditions for the migration and dissolution of fine particles and the loss of cementing materials, which accelerates the destruction and disintegration of the soil structure.

Larvicidal, bactericidal, antioxidant, hypoglycemic effects and anti-proliferative activity of phyto-synthesized Ag-ZnO nanocomposites using Eranthemum roseum (Vahl) R.Br. leaf extract against Aedes aegypti and Culex quinquefasciatus mosquito vectors

This research is conducted using zinc doped silver nanocomposite on Eranthemum roseum leaf extract. E. roseum has its own medicinal properties due its bioactive compounds. Silver and Zinc also has its own medicinal properties due to its microbial properties. Our work is aimed to combine nanoparticles with plant extract to explore the medicinal properties. The synthesized Ag-ZnO NCs is characterized using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDAX) and Transmission Electron Microscopy (TEM) analysis. The XRD analysis confirms the crystal nature of the Ag-ZnO NCs. The average shape of the nanocomposite was obtained using SEM as spherical, EDAX analysis confirming the presence of Ag, Zn and Oxygen and TEM conforms the oval shape of nanoparticles Antibacterial activity shows highest level of activity against K. pneumoniae and B. subtilis. DPPH Activity of Ag-ZnO NCs highest inhibition of 52.56 % while the ABTS analysis of Ag-ZnO NCs shows 54.28 %. Hypoglycemic activity α-amylase and α- glucosidase assay of Ag-ZnO NCs obtained good activity with maximum level of inhibition 63 % and 60 %. Anti-proliferative assay shows good activity against cancer causing cells in HepG2 human liver cancer line with 67.11 %. Larvicidal potential of Ag-ZnO NCs recorded good mortality rate against Aedes aegypti and Culex quinquefasciatus. This study confirms the maximum activity of Ag-ZnO NCs and acts as Larvicidal, Anti-proliferative, Antioxidant, Hypoglycemic agents.

Experimental and numerical study on the temporal and spatial nonlinearity evolution of focused wave

Extreme waves pose a significant threat to coastal structures. Focused wave, representing the average shape of extreme waves, is frequently employed to simulate extreme waves. Despite its convenience of generating large amplitude waves, the nonlinearity evolution of focused wave during propagation has been seldom explored. It is obvious that the nonlinearity would influence the wave shape and energy structure during focusing. This study investigates the temporal and spatial nonlinearity evolution experimentally and numerically. The experiment was conducted in a wave tank using a piston-type wavemaker. The numerical model was set up with geometry adopted from physical experiment in the commercial software FLUENT. The turbulence model RNG k–ε was employed, while the volume of fraction method was used to capture the air-water interface. The high-order harmonics were extracted from the recorded wave elevations by the four-phase decomposing method. The evolution of high-order harmonics and the energy structure were obtained. It is validated that the high-order harmonics can be reasonably estimated by multiplying linear harmonics by harmonic coefficients calculated by Stokes III or V wave theory. This paper enhances the understanding of temporal and spatial nonlinearity evolution of focused wave, which would be helpful for structure design and site selection.

Utilizing Machine Learning Algorithms for the Development of Gully Erosion Susceptibility Maps: Evidence from the Chotanagpur Plateau Region, India

Gully erosion is a serious environmental threat, compromising soil health, damaging agricultural lands, and destroying vital infrastructure. Pinpointing regions prone to gully erosion demands careful selection of an appropriate machine learning algorithm. This choice is crucial, as the complex interplay of various environmental factors contributing to gully formation requires a nuanced analytical approach. To develop the most accurate Gully Erosion Susceptibility Map (GESM) for India’s Raiboni River basin, researchers harnessed the power of two cutting-edge machine learning algorithm: Extreme Gradient Boosting (XGBoost) and Random Forest (RF). For a comprehensive analysis, this study integrated 24 potential control factors. We meticulously investigated a dataset of 200 samples, ensuring an even balance between non-gullied and gullied locations. To assess multicollinearity among the 24 variables, we employed two techniques: the Information Gain Ratio (IGR) test and Variance Inflation Factors (VIF). Elevation, land use, river proximity, and rainfall most influenced the basin’s GESM. Rigorous tests validated XGBoost and RF model performance. XGBoost surpassed RF (ROC 86% vs. 83.1%). Quantile classification yielded a GESM with five levels: very high to very low. Our findings reveal that roughly 12% of the basin area is severely affected by gully erosion. These findings underscore the critical need for targeted interventions in these highly susceptible areas. Furthermore, our analysis of gully characteristics unveiled a predominance of V-shaped gullies, likely in an active developmental stage, supported by an average Shape Index (SI) value of 0.26 and a mean Erosivness Index (EI) of 0.33. This research demonstrates the potential of machine learning to pinpoint areas susceptible to gully erosion. By providing these valuable insights, policymakers can make informed decisions regarding sustainable land management practices.

Calculating absorption and fluorescence spectra for chromophores in solution with ensemble Franck-Condon methods.

Accurately modeling absorption and fluorescence spectra for molecules in solution poses a challenge due to the need to incorporate both vibronic and environmental effects, as well as the necessity of accurate excited state electronic structure calculations. Nuclear ensemble approaches capture explicit environmental effects, Franck-Condon methods capture vibronic effects, and recently introduced ensemble-Franck-Condon approaches combine the advantages of both methods. In this study, we present and analyze simulated absorption and fluorescence spectra generated with combined ensemble-Franck-Condon approaches for three chromophore-solvent systems and compare them to standard ensemble and Franck-Condon spectra, as well as to the experiment. Employing configurations obtained from ground and excited state abinitio molecular dynamics, three combined ensemble-Franck-Condon approaches are directly compared to each other to assess the accuracy and relative computational time. We find that the approach employing an average finite-temperature Franck-Condon line shape generates spectra nearly identical to the direct summation of an ensemble of Franck-Condon spectra at one-fourth of the computational cost. We analyze how the spectral simulation method, as well as the level of electronic structure theory, affects spectral line shapes and associated Stokes shifts for 7-nitrobenz-2-oxa-1,3-diazol-4-yl and Nile red in dimethyl sulfoxide and 7-methoxy coumarin-4-acetic acid in methanol. For the first time, our studies show the capability of combined ensemble-Franck-Condon methods for both absorption and fluorescence spectroscopy and provide a powerful tool for simulating linear optical spectra.

Osteon shape variation in the femoral diaphysis: A geometric-morphometric approach on human cortical bone microstructure in an elderly sample.

Geometric morphometrics (GMM) have been applied to understand morphological variation in biological structures. However, research studying cortical bone through geometric histomorphometrics (GHMM) is scarce. This research aims to develop a landmark-based GHMM protocol to depict osteonal shape variation in the femoral diaphysis, exploring the role of age and biomechanics in bone microstructure. Proximal, midshaft, and distal anatomical segments from the femoral diaphysis of six individuals were assessed, with 864 secondary intact osteons from eight periosteal sampling areas being manually landmarked. Observer error was tested using Procrustes ANOVA. Average osteonal shape and anatomical segment-specific variation were explored using principal component analysis. Osteon shape differences between segments were examined using canonical variate analysis (CVA). Sex differences were assessed through Procrustes ANOVA and discriminant function analysis (DFA). The impact of osteonal size on osteonal shape was investigated. High repeatability and reproducibility in osteon shape landmarking were reported. The average osteon shape captured was an elliptical structure, with PC1 reflecting more circular osteons. Significant differences in osteon shape were observed between proximal and distal segments according to CVA. Osteon shape differed between males and females, with DFA showing 52% cross-validation accuracies. No effect of size on shape was reported. Osteonal shape variation observed in this study might be explained by the elderly nature of the sample as well as biomechanical and physiological mechanisms playing different roles along the femoral diaphysis. Although a larger sample is needed to corroborate these findings, this study contributes to the best of our knowledge on human microanatomy, proposing a novel GHMM approach.

Nucleation, Development and Healing of Micro-Cracks in Shape Memory Polyurethane Subjected to Subsequent Tension Cycles.

Thermoresponsive shape memory polymers (SMPs) have garnered increasing interest for their exceptional ability to retain a temporary shape and recover the original configuration through temperature changes, making them promising in various applications. The SMP shape change and recovery that happen due to a combination of mechanical loading and appropriate temperatures are related to its particular microstructure. The deformation process leads to the formation and growth of micro-cracks in the SMP structure, whereas the subsequent heating over its glass transition temperature Tg leads to the recovery of its original shape and properties. These processes also affect the SMP microstructure. In addition to the observed macroscopic shape recovery, the healing of micro-crazes and micro-cracks that have nucleated and developed during the loading occurs. Therefore, our study delves into the microscopic aspect, specifically addressing the healing of micro-cracks in the cyclic loading process. The proposed research concerns a thermoplastic polyurethane shape memory polymer (PU-SMP) MM4520 with a Tg of 45 °C. The objective of the study is to investigate the effect of the number of tensile loading-unloading cycles and thermal shape recovery on the evolution of the PU-SMP microstructure. To this end, comprehensive research starting from structural characterization of the initial state and at various stages of the PU-SMP mechanical loading was conducted. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS) and scanning electron microscopy (SEM) were used. Moreover, the shape memory behavior in the thermomechanical loading program was investigated. The obtained average shape fixity value was 99%, while the shape recovery was 92%, which confirmed good shape memory properties of the PU-SMP. Our findings reveal that even during a single loading-unloading tension cycle, crazes and cracks nucleate on the surface of the PU-SMP specimen, whereas the subsequent temperature-induced shape recovery process carried out at the temperature above Tg enables the healing of micro-cracks. Interestingly, the surface of the specimen after three and five loading-unloading cycles did not exhibit crazes and cracks, although some traces of cracks were visible. The traces disappeared after exposing the material to heating at Tg + 20 °C (65 °C) for 30 min. The crack closure phenomenon during deformation, even without heating over Tg, occurred within three and five subsequent cycles of loading-unloading. Notably, in the case of eight loading-unloading cycles, cracks appeared on the surface of the PU-SMP and were healed only after thermal recovery at the particular temperature over Tg. Upon reaching a critical number of cycles, the proper amount of energy required for crack propagation was attained, resulting in wide-open cracks on the material's surface. It is worth noting that WAXS analysis did not indicate strong signs of typical highly ordered structures in the PU-SMP specimens in their initial state and after the loading history; however, some orientation after the cyclic deformation was observed.

Shape variations of pelvis in different classes of dogs using geometric morphometry.

The ossa coxae are the bones that connect the hindlimbs to the axial skeleton. The right and left os coxae join at the median plane to form the pelvis. In this study, variations in pelvis shape and the asymmetric structure of the pelvis were investigated across different classes of dogs. To achieve this, computed tomography images of the pelvis were obtained from 35 dogs, and 3D modelling of the pelvis was created. Subsequently, 45 landmarks were identified on these models. As a result of the Principal Component Analysis, the shape variation was observed in the pelvic canal and crista iliaca. Directional asymmetry between Principal Component 1 and Principal Component 2 accounted for 33.84% of the total variation, while fluctuating asymmetry contributed 23.66%. Canonical variate analysis revealed that canonical variate (CV) 1 explained 56.56% of the total variation between groups, with CV 2 explained 28.98%. Male dogs exhibited greater pelvic variation than females. Procrustes ANOVA indicated that the greatest proportion of shape variation corresponds to the effect of differences among individuals. While directional asymmetry was statistically significant, fluctuating asymmetry was not. Male dogs displayed more pronounced pelvic shape asymmetry, typically towards the right. Gundogs had a narrower pelvic canal and a wide crista iliaca, whereas terriers had a wider pelvic canal and smaller crista iliaca in shape. Geometric morphometry enables statistical analysis and the derivation of average shapes from samples, making it a vital tool in veterinary anatomy. This study provides insights into pelvic geometric morphometry across different classes of dogs.