Shape Changes Research Articles

Shedding light on evolution of Raman line shape with probing laser power: Light-induced perturbation in electron-phonon coupling.

The laser power mediated changes in the Raman line shape have been considered in terms of interference between discrete phonon states ρ and the electronic continuum states ϰ contributed by Urbach tail states. The laser-induced effects are treated in terms of the increase in the surface temperature and thereby the scaling of electronic disorder, i.e., Urbach energy, which can further contribute to the electron-phonon interactions. Therefore, the visualization of this effect is attempted analytically as a perturbation term in the Hamiltonian, which clearly accounts for the observed changes with laser power. This has been investigated based on the experimental results of laser power dependent Raman spectra of bulk EuFeO3 and silicon nanowires, which are found to provide convincing interpretations.

Activated carbon derived from corncob via hydrothermal carbonization as a promising electrode for supercapacitors

Activated carbon has been synthesized from corncob via hydrothermal treatment at 200 °C for 7 h with and without activating agents, followed by carbonization at 400 °C for 3 h. The X-ray diffraction patterns show peaks corresponding to the amorphous and graphitic carbon phases. The SEM studies reveal meso and macro pores. The H3PO4 treated sample (CC-H-400) shows the highest Brunauer-Emmett-Teller surface area (68.54 m2 g-1). Raman spectra indicate the typical D and G bands. The CC-H-400 shows the highest specific capacitance value of 41 F g-1 among all the samples. The energy and power density values of the supercapacitor working electrode in a three-electrode setup are 5.7 W h kg-1 and 500.4 W kg-1, respectively, for the CC-H-400. Furthermore, the CC-H-400 exhibits excellent stability with a retention rate of 88 % after 2000 charge-discharge cycles at 10 A g-1 without any shape change, as well as a low equivalence series resistance (ESR) value of 3.96 Ω.

Theoretical and experimental investigations on a data-driven trajectory planning scheme for dynamic shape control of piezo-actuated compliant morphing structures

Piezo-actuated compliant morphing structures can transmit motion and force via elastic deformation with lower weight, simplified design, and higher accuracy, a typical example is the variable camber wing. However, the rapid shape change of compliant structures is a challenging control problem because it often results in a high level of vibration due to the structural flexibility necessary to achieve the morphing requirement. This study presents a model-free data-driven trajectory planning approach based on spline curves and surrogate-based optimization (SBO) to obtain smooth “rest-to-rest” morphing trajectories. The macro-fiber composite (MFC) patches are used for piezoelectric actuators to generate elastic deformation. The flexible beam and variable camber wing are used for both linear numerical simulation and experimental tests with various nonlinearities and uncertainties. An optimization criterion is proposed to minimize both transient and residual vibrations during the “rest-to-rest” motion. An extraordinarily terminal displacement error function is added to eliminate the effects of the hysteresis and creep of the actuator. The control inputs, i.e., voltage profiles for the MFCs, are defined using cubic spline curves via only a few control points. Then, the optimization problem is solved by employing a Kriging surrogate model-based algorithm integrated with the expected improvement (EI) infilling-sampling criterion, which constructs an efficient algorithm similar to reinforcement learning. The optimal morphing trajectories can be highly efficiently obtained by using only 4 control points and less than 150 samplings. The experimental results of both the plate model and the variable camber wing model show that the proposed method can not only achieve a smooth dynamic morphing trajectory with minimized vibration but also automatically compensate for hysteresis and creep. The proposed method provides an effective means for the rapid realization of an optimized morphing trajectory for compliant morphing structures.

Scale-inspired programmable robotic structures with concurrent shape morphing and stiffness variation.

Biological organisms often have remarkable multifunctionality through intricate structures, such as concurrent shape morphing and stiffness variation in the octopus. Soft robots, which are inspired by natural creatures, usually require the integration of separate modules to achieve these various functions. As a result, the whole structure is cumbersome, and the control system is complex, often involving multiple control loops to finish a required task. Here, inspired by the scales that cover creatures like pangolins and fish, we developed a robotic structure that can vary its stiffness and change shape simultaneously in a highly integrated, compact body. The scale-inspired layered structure (SAILS) was enabled by the inversely designed programmable surface patterns of the scales. After fabrication, SAILS was inherently soft and flexible. When sealed in an elastic envelope and subjected to negative confining pressure, it transitioned to its designated shape and concurrently became stiff. SAILS could be actuated at frequencies as high as 5 hertz and achieved an apparent bending modulus change of up to 53 times between its soft and stiff states. We further demonstrated both the versatility of SAILS by developing a soft robot that is amphibious and adaptive and tunable landing systems for drones with the capacity to accommodate different loads.

Surface Treatment Strategies and Their Impact on the Material Behavior and Interfacial Adhesion Strength of Shape Memory Alloy NiTi Wire Integrated in Glass Fiber-Reinforced Polymer Laminate Structures

Over the past few decades, there has been a growing trend in designing multifunctional materials and integrating various functions into a single component structure without defects. This research addresses the contemporary demand for integrating multiple functions seamlessly into thermoplastic laminate structures. Focusing on NiTi-based shape memory alloys (SMAs), renowned for their potential in introducing functionalities like strain measurement and shape change, this study explores diverse surface treatments for SMA wires. Techniques such as thermal oxidation, plasma treatment, chemical activation, silanization, and adhesion promoter coatings are investigated. The integration of NiTi SMA into Glass Fiber-Reinforced Polymer (GFRP) laminates is pursued to enable multifunctional properties. The primary objective is to evaluate the influence of these surface treatments on surface characteristics, including roughness, phase changes, and mechanical properties. Microstructural, analytical, and in situ mechanical characterizations are conducted on both raw and treated SMA wires. The subsequent incorporation of SMA wires after characterization into GFRP laminates, utilizing hot-press technology, allows for the determination of interfacial adhesion strength through pull-out tensile tests.

Effectiveness of sequential method pure single-port lumpectomy-breast conserving surgery for early-stage breast cancer in different quadrants

To compare the effectiveness of sequential method pure single-port lumpectomy-breast conserving surgery (SMPSL-BCS) in treating early-stage breast cancer patients with tumors in different quadrants. A retrospective analysis was conducted on 200 early-stage breast cancer female patients admitted between January 2023 and December 2023. According to the quadrant where the tumor was located, the patients were allocated into the upper outer quadrant group (UO group), lower outer quadrant group (LO group), upper inner quadrant group (UI group), and lower inner quadrant group (LI group), with 50 cases in each group. There was no significant difference ( P>0.05) in the baseline data, including age, body mass index, smoking history, marital status, comorbidities, affected breast side, maximum tumor diameter on ultrasound, maximum pathological tumor diameter, clinical tumor stage, molecular subtype, and disease duration. The operation time, intraoperative blood loss, postoperative drainage volume, and extubation time were recorded and compared between groups. Additionally, the occurrence of early-stage complications (1-3 months after operation; including subcutaneous fluid accumulation, incision infection, superficial skin burns) and late-stage complications (>3 months after operation; including pectoralis major muscle adhesion, changes in breast appearance and shape, sensory discomfort) were assessed. At 6 months after operation, the cosmetic outcome of breast-conserving surgery was rated for all groups. The UO group had the shortest operation time, followed by the UI group, LO group, and LI group, showing significant differences between groups ( P<0.05). The UO group had the least intraoperative blood loss, followed by the LO group, UI group, and LI group; except for the difference between UO group and LO group, which was not significant ( P>0.05), the differences between the other groups were significant ( P<0.05). The UO group had the least postoperative drainage volume, followed by the LO group, UI group, and LI group; except for the difference between LO group and UI group, which was not significant ( P>0.05), the differences between the other groups were significant ( P<0.05). The extubation time of the LI group was significantly longer than that of the other groups ( P<0.05). All patients were followed up 4-12 months, with an average of 8 months. And 193 patients were followed up more than 6 months, including 48 patients in UO group, 47 in LO group, 49 in UI group, and 49 in LI group. In the early-stage period, the LI group had a higher incidence of subcutaneous fluid accumulation after tube removal compared to the UO group and LO group ( P<0.05), while there was no significant difference in the incidences of other early complications between groups ( P>0.05). In the late-stage period, the LI group had significantly higher incidences of pectoralis major muscle adhesion and changes in breast appearance and shape than UO group and LO group ( P<0.05), and a significantly higher incidence of sensory discomfort than UO group ( P<0.05). There was no significant difference in the incidences of other late-stage complications between groups ( P>0.05). At 6 months after operation, the cosmetic outcomes of breast-conserving surgery were significantly better in UO group, LO group, and UI group than in LI group ( P<0.05); there was no significant difference between the other groups ( P>0.05). In the treatment of early-stage breast cancer using SMPSL-BCS, patients with tumors located in the upper outer quadrant show the best effectiveness. The effectivenesses are similar for patients with tumors in the lower outer and upper inner quadrants. However, patients with tumors in the lower inner quadrant do not experience significant advantages. Therefore, it is recommended that SMPSL-BCS should not be the first-choice surgical method for patients with tumors in the lower inner quadrant.

Pressure-induced optical anisotropy of HfS2

The effect of pressure on Raman scattering (RS) in bulk HfS2 is investigated under hydrostatic and non-hydrostatic pressure conditions. The RS line shape does not change significantly in the hydrostatic regime up to P = 9.6 GPa, showing a systematic blueshift of the spectral features. In a non-hydrostatic environment, seven peaks appear in the spectrum at P = 7 GPa, which dominate the RS line shape up to P = 10.5 GPa. The change in the RS line shape manifests a pressure-induced phase transition in HfS2. The simultaneous observation of both low-pressure (LP) and high-pressure (HP) related RS peaks suggests the coexistence of two different phases over a wide pressure range. It is found that the HP-related phase is metastable and persists during the decompression cycle down to P = 1.2 GPa, while the LP-related features eventually recover at even lower pressure. The angle-resolved polarized RS performed under P = 7.4 GPa revealed a strong in-plane anisotropy of both the LP-related A1g mode and the HP peaks. The anisotropy is related to the possible distortion of the structure induced by the non-hydrostatic component of the pressure. The results are explained in terms of a distorted Pnma phase as a possible pressure-induced phase of HfS2.

Sexual dimorphism in the dwarf round ray Urotrygon nana.

This paper presents information on the morphological, morphometric, and dental sex differences in the dwarf round ray Urotrygon nana. We recorded 12 morphological traits, sex, the distribution pattern of dermal denticles, the number of tooth rows, and the tooth shape of 466 individuals. The disc width of females ranged from 50 to 172 mm and that of males ranged from 53 to 135 mm. A neuronal classification model and a correspondence analysis showed that female disc width was 21.5% broader, and the distance from the rostrum to the anus was 17.7% longer than that of males, whereas males presented 19.5% greater distance between the nostrils, 9.7% greater preorbital snout length, 6.8% greater cloaca to caudal-fin length, 2.7% greater interorbital distance, and 1.1% greater total length than females. The disc of adult males, including the abdominal cavity area, was densely covered with dermal denticles, which were slightly larger than those observed in females. Females presented homodont dentition with molariform teeth and a smooth lozenge-shaped crown with rounded margins. Males exhibited homodonty but with tooth morphology variations in individuals of different sizes (from molariforms to sharper cusp teeth). There were changes in disc shape (from subcircular to oval), distribution and size of dermal denticles (more abundant and larger), and tooth shape (from molariform to monocuspid teeth) during male development, from neonates to adults. U. nana exhibited sexual dimorphism in size, disc shape, number and shape of teeth, and distribution and size of dermal denticles.

A novel homozygous missense TTC12 variant identified in an infertile Pakistani man with severe oligoasthenoteratozoospermia and primary ciliary dyskinesia.

TTC12 is a cytoplasmic and centromere-localized protein that plays a role in the proper assembly of dynein arm complexes in motile cilia in both respiratory cells and sperm flagella. This finding underscores its significance in cellular motility and function. However, the wide role of TTC12 in human spermatogenesis-associated primary ciliary dyskinesia (PCD) still needs to be elucidated. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify potentially pathogenic variants causing PCD and multiple morphological abnormalities of sperm flagella (MMAF) in an infertile Pakistani man. Diagnostic imaging techniques were used for PCD screening in the patient. Real-time polymerase chain reaction (RT‒PCR) was performed to detect the effect of mutations on the mRNA abundance of the affected genes. Papanicolaou staining and scanning electron microscopy (SEM) were carried out to examine sperm morphology. Transmission electron microscopy (TEM) was performed to examine the ultrastructure of the sperm flagella, and the results were confirmed by immunofluorescence staining. Using WES and Sanger sequencing, a novel homozygous missense variant (c.C1069T; p.Arg357Trp) in TTC12 was identified in a patient from a consanguineous family. A computed tomography scan of the paranasal sinuses confirmed the symptoms of the PCD. RT-PCR showed a decrease in TTC12 mRNA in the patient's sperm sample. Papanicolaou staining, SEM, and TEM analysis revealed a significant change in shape and a disorganized axonemal structure in the sperm flagella of the patient. Immunostaining assays revealed that TTC12 is distributed throughout the flagella and is predominantly concentrated in the midpiece in normal spermatozoa. In contrast, spermatozoa from patient deficient in TTC12 showed minimal staining intensity for TTC12 or DNAH17 (outer dynein arms components). This could lead to MMAF and result in male infertility. This novel TTC12 variant not only illuminates the underlying genetic causes of male infertility but also paves the way for potential treatments targeting these genetic factors. This study represents a significant advancement in understanding the genetic basis of PCD-related infertility.

Bone remodeling after revision total hip arthroplasty for large acetabular defects.

Large acetabular bone defects are challenging in hip revision surgery. Clinical assessment is crucial to evaluate modern technologies in surgical reconstruction. We aimed to better understand the bone remodeling that occurs following acetabular reconstruction. Our objectives were: (1) To characterize changes in the shape of the pelvis by studying sequential computed tomography (CT) scans collected immediately and 1-year postoperatively and (2) to identify which part of the pelvis is most susceptible to remodeling. We used the CT scans taken at two timepoints, of 24 patients with acetabular bone defects classified as Paprosky IIIB, treated with three-dimensional (3D)-printed custom-made acetabular implants. Segmented 3D models of the bony pelvis were co-registered using three different techniques. A global co-registration of the full pelvis was conducted, followed by the co-registration of the innominate bone and then ilium only, on the ipsilateral reconstructed side. The relative movements of the ilium, ischium, and pubis were analyzed from visual inspection and using co-registration metrics (root mean square error and intersection over union). No bone remodeling was found in 14/24 patients (58%). The co-registration of the innominate bone indicated bone remodeling in five cases (21%), while the remaining five cases (21%) presented remodeling in the global co-registration but not the innominate bone co-registration, suggestive of changes occurring at the sacroiliac joint. Changes in the pelvic shape were greatest at the pubis and ischium. Bone remodeling may occur in complex cases of Paprosky type IIIB defects, after acetabular reconstruction (occurrence of 21%, 5/24 cases). Surgeons and engineers should consider this when monitoring implant migration.

β-H-Spectrin is a key component of an apical-medial hub of proteins during cell wedging in tube morphogenesis.

Coordinated cell shape changes are a major driver of tissue morphogenesis, with apical constriction of epithelial cells leading to tissue bending. During the tube budding of the salivary glands in the Drosophila embryo we previously identified a key interplay between the apical-medial actomyosin, driving apical constriction, with the underlying longitudinal microtubule array. At this microtubule-actomyosin-interface a hub of proteins accumulates: as shown before, the microtubule-actin-crosslinker Shot and the minus-end-binder Patronin, and now identified two actin-crosslinkers, β-H-Spectrin and Filamin, and the multi-PDZ-protein Big-bang. We show that tissue-specific-degradation of β-H-Spectrin led to reduction of apical-medial F-actin, Shot, Patronin and Big-bang and concomitant defects in apical constriction, but residual Patronin was still sufficient to assist microtubule reorganisation. Contrary to Patronin and Shot, neither β-H-Spectrin nor Big bang required microtubules for their localisation. β-H-Spectrin was instead recruited via binding to apical-medial phosphoinositides. Overexpression of β-H-33 containing the PH domain displaced endogenous β-H-Spectrin and led to strong morphogenetic defects. This protein hub therefore required the synergy and coincidence of membrane- and microtubule-associated components for its assembly and function in sustaining the apical constriction during tubulogenesis.

First-Principles Modeling of the Absorption Spectrum of Crystal Violet in Solution: The Importance of Environmentally Driven Symmetry Breaking.

Theoretical spectroscopy plays a crucial role in understanding the properties of the materials and molecules. One of the most promising methods for computing optical spectra of chromophores embedded in complex environments from the first principles is the cumulant approach, where both (generally anharmonic) vibrational degrees of freedom and environmental interactions are explicitly accounted for. In this work, we verify the capabilities of the cumulant approach in describing the effect of complex environmental interactions on linear absorption spectra by studying Crystal Violet (CV) in different solvents. The experimental absorption spectrum of CV strongly depends on the nature of the solvent, indicating strong coupling to the condensed-phase environment. We demonstrate that these changes in absorption line shape are driven by an increased splitting between absorption bands of two low-lying excited states that is caused by a breaking of the D3 symmetry of the molecule and that in polar solvents, this symmetry breaking is mainly driven by electrostatic interactions with the condensed-phase environment rather than distortion of the structure of the molecule, in contrast with conclusions reached in a number of previous studies. Our results reveal the importance of explicitly including a counterion in the calculations in nonpolar solvents due to electrostatic interactions between CV and the ion. In polar solvents, these interactions are strongly reduced due to solvent screening effects, thus minimizing the symmetry breaking. Computed spectra in methanol are found to be in reasonable agreement with the experiment, demonstrating the strengths of the outlined approach in modeling strong environmental interactions.

Composite branched and linear F-actin maximize myosin-induced membrane shape changes in a biomimetic cell model

The architecture of the actin cortex determines the generation and transmission of stresses, during key events from cell division to migration. However, its impact on myosin-induced cell shape changes remains unclear. Here, we reconstitute a minimal model of the actomyosin cortex with branched or linear F-actin architecture within giant unilamellar vesicles (GUVs, liposomes). Upon light activation of myosin, neither the branched nor linear F-actin architecture alone induces significant liposome shape changes. The branched F-actin network forms an integrated, membrane-bound “no-slip boundary” -like cortex that attenuates actomyosin contractility. By contrast, the linear F-actin network forms an unintegrated “slip boundary“ -like cortex, where actin asters form without inducing membrane deformations. Notably, liposomes undergo significant deformations at an optimized balance of branched and linear F-actin networks. Our findings highlight the pivotal roles of branched F-actin in force transmission and linear F-actin in force generation to yield membrane shape changes.

IIAM: Intra and Inter Attention with Mutual Consistency Learning Network for Medical Image Segmentation.

Medical image segmentation provides a reliable basis for diagnosis analysis and disease treatment by capturing the global and local features of the target region. To learn global features, convolutional neural networks are replaced with pure transformers, or transformer layers are stacked at the deepest layers of convolutional neural networks. Nevertheless, they are deficient in exploring local-global cues at each scale and the interaction among consensual regions in multiple scales, hindering the learning about the changes in size, shape, and position of target objects. To cope with these defects, we propose a novel Intra and Inter Attention with Mutual Consistency Learning Network (IIAM). Concretely, we design an intra attention module to aggregate the CNN-based local features and transformer-based global information on each scale. In addition, to capture the interaction among consensual regions in multiple scales, we devise an inter attention module to explore the cross-scale dependency of the object and its surroundings. Moreover, to reduce the impact of blurred regions in medical images on the final segmentation results, we introduce multiple decoders to estimate the model uncertainty, where we adopt a mutual consistency learning strategy to minimize the output discrepancy during the end-to-end training and weight the outputs of the three decoders as the final segmentation result. Extensive experiments on three benchmark datasets verify the efficacy of our method and demonstrate superior performance of our model to state-of-the-art techniques.

BELUGA WHALE LION OPTIMIZATION IN DEEP-NETS FOR HUMAN AGE ESTIMATION USING HAND X-RAY

Bones undergo significant changes in size and shape with the growth of the child, and bone age estimation is crucial for determining the growth, genetic and endocrine disorders in children. Hand X-ray images are extensively utilized for diagnosing disorders in children. The variation in the chronological age and bone age indicates the presence of endocrine disorders, genetic problems, and growth abnormalities. Traditionally, bone age is estimated manually by inspecting the X-ray images, which is extremely time-consuming and prone to error. Further, the accuracy of the bone estimate depends on the experience of the medical practitioner, and thus it suffers from intra- and inter-observer variability. Hence, to overcome these issues, it is essential to devise automatic methods that can estimate the bone with high accuracy and in a short duration. In this work, bone age is estimated using a Deep Residual Network (DRN), whose learnable factors are adjusted using the devised Beluga Whale Lion Optimization (BWLO) algorithm. Further, the BWLO_DRN is examined for its superiority considering metrics, like accuracy, True Positive Rate (TPR), and True Negative Rate (TNR), and the corresponding values of 89.8%, 86.8%, and 90% are found to be achieved from the experimental results.

Applying the starquake model to study the formation of elastic mountains on spinning neutron stars

Abstract When a neutron star is spun-up or spun-down, the changing strains in its solid elastic crust can give rise to sudden fractures known as starquakes. Early interest in starquakes focused on their possible connection to pulsar glitches. While modern glitch models rely on pinned superfluid vorticity rather than crustal fracture, starquakes may nevertheless play a role in the glitch mechanism. Recently, there has been interest in the issue of starquakes resulting in non-axisymmetric shape changes, potentially linking the quake phenomenon to the building of neutron star mountains, which would then produce continuous gravitational waves. Motivated by this issue, we present a simple model that extends the energy minimisation-based calculations, originally developed to model axisymmetric glitches, to also include non-axisymmetric shape changes. We show that the creation of a mountain in a quake necessarily requires a change in the axisymmetric shape too. We apply our model to the specific problem of the spin-up of an initially non-rotating star, and estimate the maximum mountain that can be built in such a process, subject only to the constraints of energy and angular momentum conservation.

Changes in the wing shape and size in fruit flies exposed to micro and nanoplastics

Geometric morphometrics analysis (GMA) is a well-known technique to identify minute changes in Drosophila wings. This study aimed to determine potential changes in Drosophila wings shape and size after exposure to polystyrene nanoplastics (NPs) (50 nm) and microplastics (MPs) (1 μm). Flies were exposed from eggs to pupal eclosion and analyzed using GMA. Results revealed a difference in shape and size between male and female wings, as expected, due to sexual dimorphism. Therefore, wings were analyzed by sex. Wings of MPs and NPs treated females were elongated compared to controls and had a constriction of the wing joint. Additionally, MPs treated female flies had the most dissimilar shape compared to controls. In male flies, NPs flies had smaller wings compared to MPs and control flies. Compared to control, NPs wings of males were shrunken at the joint and in the entire proximal region of the wing. However, male MPs wings had a narrower anal region and were slightly elongated. These results reveal that wing shape and size can change in a different way based on the sex of the flies and size of plastic particles that larvae interacted with. All the changes in the wings occurred only within the normally allowed wing variation and treatment with NPs/MPs did not cause development of the aberrant phenotypes. Results can pave the way for further understanding of how MPs and NPs can alter phenotypes of flies.

A global springback compensation method for manufacturing metallic seal ring with complex cross-section and submillimeter precision

The fabrication of complex thin-walled components with irregular cross-sectional geometries often necessitates multi-pass forming processes. The springback phenomena at the microscale level contribute significantly difficulty to the precise control of geometrical accuracy for such components. To achieve submillimeter precision control of micro features in metal seal rings, this research proposed a global springback compensation method to facilitate the attainment of the optimized surfaces of dies. Through the analysis of changes in cross-sectional shape, stress distribution and bending moment in the multiple stages, several partition points were set up to divide the cross-section into four zones. For a partitional control of the manufactured surface, the compensation magnitudes for each segment are determined by iteratively refining the compensation factors using the secant method. The iteration of compensation factors is based on the deviation of dimensions measured by finite element simulation, which greatly saves experimental costs. The experimental results indicate that the predictive dimensional alterations by the global compensation agree with the experimental ones exhibiting a maximum error of less than 3 %. Furthermore, the springback behavior during the unloading and trimming stages coupling caused a dimensional error of 14.9 % for the wave width and 8.3 % for the peak width. Following the application of coupled compensation through two iterations, a distinct decrease in the relative average errors of springback values for both part width and peak width, achieving reductions to 2.4 % and 0.6 %, respectively. Compared to the traditional single springback compensation technique, the global compensation strategy effectively mitigates the out-of-tolerance issues induced by the trimming process.

Sex differences in pelvic size and shape in the striped field mouse from Slovakia

Morphometric analysis and evaluation of 260 striped field mice (Apodemus agrarius) were carried out to identify sexual size dimorphism in pelvic bones regarding the age of individuals and the reproductive history of females. Pelvic size was found to differ between subadult and adult individuals of both sexes. A comparison using the Mann–Whitney U test between the right and left parts of the pelvis showed statistically non-significant differences between the pelvis dimensions. In the inter-sexual comparison of both ages (subadult, adult), statistically significant differences were found for only four traits in adults: length of the coxal bone (LP1), width of the ischiopubis (WP1), length of the obturator foramen (LSF) and width of the obturator foramen (WSF). The two indices (WSF/LSF and WP1/LP2) evaluated clearly reflected changes in the pelvic shape, which were most pronounced in adult mice. For the group of subadult males and females, the differences in measured traits and indices were not as pronounced. Several analyses, such as the Mann–Whitney U test, principal component analysis (PCA) as well as discriminant analysis (DFA), showed sex differences in pelvic morphology and shape, although the two sexes overlapped. Similarly, one-way ANCOVA showed that there was a significant difference between the sexes for the adjusted means. Analyses showed that for a given body mass, it appears that females tend to have larger pelvises. Thus, the sexual dimorphism of females was related to pelvic size and shape in A. agrarius. The breeding history showed differences in pelvic dimensions in following direction: the nulliparous < primigravid < primiparous direction.

Modeling the mechanosensitive collective migration of cells on the surface and the interior of morphing soft tissues.

Cellular contractility, migration, and extracellular matrix (ECM) mechanics are critical for a wide range of biological processes including embryonic development, wound healing, tissue morphogenesis, and regeneration. Even though the distinct response of cells near the tissue periphery has been previously observed in cell-laden microtissues, including faster kinetics and more prominent cell-ECM interactions, there are currently no models that can fully combine coupled surface and bulk mechanics and kinetics to recapitulate the morphogenic response of these constructs. Mailand et al. (Biophys J 117(5):975-986, 2019) had shown the importance of active elastocapillarity in cell-laden microtissues, but modeling the distinct mechanosensitive migration of cells on the periphery and the interior of highly deforming tissues has not been possible thus far, especially in the presence of active elastocapillary effects. This paper presents a framework for understanding the interplay between cellular contractility, migration, and ECM mechanics in dynamically morphing soft tissues accounting for distinct cellular responses in the bulk and the surface of tissues. The major novelty of this approach is that it enables modeling the distinct migratory and contractile response of cells residing on the tissue surface and the bulk, where concurrently the morphing soft tissues undergo large deformations driven by cell contractility. Additionally, the simulation results capture the changes in shape and cell concentration for wounded and intact microtissues, enabling the interpretation of experimental data. The numerical procedure that accounts for mechanosensitive stress generation, large deformations, diffusive migration in the bulk and a distinct mechanism for diffusive migration on deforming surfaces is inspired from recent work on bulk and surface poroelasticity of hydrogels involving elastocapillary effects, but in this work, a two-field weak form is proposed and is able to alleviate numerical instabilities that were observed in the original method that utilized a three-field mixed finite element formulation.