Irregular morphology is an important predictor of rupture risk in cerebral aneurysms. However, its evaluation has largely relied on subjective visual assessment of two-dimensional images, resulting in limited reproducibility. This study aimed to establish a quantitative method for assessing aneurysm shape irregularity and to identify morphological variables that best correspond to expert visual judgment.We retrospectively analyzed 184 aneurysms reconstructed from three-dimensional computed tomography angiography. Two independent neurosurgeons classified aneurysms as irregular shape only when both agreed on irregularity; all others were defined as regular shape. Morphological variables, including conventional geometric parameters and convex hull-based irregularity indices such as the undulation area index, which is derived from the difference in surface area between the aneurysm and its convex hull, were used to quantify deviations from an ideal shape. Receiver operating characteristic curve analysis was performed to evaluate their ability to discriminate irregular shape from regular shape.Interrater agreement was moderate (κ = 0.36). All irregularity indices and most conventional variables were significantly higher in the irregular shape group (all p < 0.001). The receiver operating characteristic analysis showed that undulation area index had the highest diagnostic performance (area under the curve = 0.818, sensitivity = 0.779, specificity = 0.738, and optimal cutoff = 0.013).Among the evaluated morphological variables, undulation area index demonstrated the highest ability to discriminate visually defined irregular shape aneurysms. Undulation area index provides an objective and reproducible measure of aneurysm shape irregularity and may contribute to improved risk assessment.

Several animal groups produce two morphologically distinct types of sperm in the testis, including fertilizing eusperm and non-fertilizing parasperm. This phenomenon, termed sperm dimorphism, is considered to play a role in reproductive strategies such as sperm competition. In the marine gastropod Conomurex luhuanus, parasperm possess numerous globular bodies and the cilia-based undulating membranes. However, the function of the globular bodies and the motility of the undulating membranes remain unclear. Here, we describe the process and regulation of globular body exocytosis in parasperm. Upon dilution in artificial seawater, exocytosis occurs via membrane fusion between globular body membrane and the plasma membrane, followed by the release of globular body contents. Exocytosis was markedly suppressed under Ca2+ -deficient conditions but was enhanced by increases in intracellular Ca2+ induced by an ionophore A23187. In contrast, both the absence of extracellular K⁺ and high extracellular K⁺ concentrations enhanced exocytosis. On the other hand, the direction of wave propagation of the undulating membrane was reversed by high extracellular Ca2+ concentrations or by treatment with A23187, whereas it was suppressed under high extracellular K⁺ conditions. Together, these findings indicate that globular body exocytosis and changes in swimming direction are regulated by different mechanisms. This study provides novel insight into the post-ejaculatory behavior and potential function of parasperm within the female reproductive tract of gastropods.

Phasmatodea is a relatively small order of polyneopteran insects, comprising over 3100 described species, the vast majority of which belong to the suborder Euphasmatodea. Although this group exhibits considerable morphological diversity and a broad geographic distribution, its internal systematics remains only partially resolved. Current knowledge of euphasmatodean spermatology is notably fragmented, as existing studies have predominantly emphasized the conservation of a general sperm model. The present study describes the male reproductive system and provides a detailed ultrastructural analysis of the spermatozoon of Hesperophasma planulum (Westwood, 1859), a species endemic to the eastern region of Hispaniola Island, whose systematic placement remains controversial. The spermatozoa of H. planulum exhibit several hallmark features of euphasmatodean sperm, including a simplified acrosomal lacking a perforatorium, a well-developed centriolar adjunct associated with a peculiar centriolar structure, two large, laminated, accessory bodies alongside the axoneme, that replace the mitochondrial derivatives, and a flattened flagellum provided with an "undulating membrane". However, several traits, including a significant reduction in total length, a remarkably short nucleus, a substantially elongated centriolar adjunct, and exceptionally large, laminated accessory bodies, distinguish the spermatozoon of this species from all other euphasmatodeans described to date. These findings demonstrate that spermatological characters provide valuable taxonomic markers within Euphasmatodea, and integrating them with existing datasets will aid in resolving long-standing systematic uncertainties within the suborder.

Spiral growth in two-dimensional (2D) materials has conventionally been explained by single screw dislocation mechanisms, yet a complete multiscale understanding remains elusive due to the intricate nature of screw dislocation structures. Here, we present a stabilization approach through metallic transition metal dichalcogenides (m-TMDs) overlayers on spiral semiconducting TMDs (s-TMDs), which enables unprecedentedly robust atomic-resolution imaging of screw dislocations in cross-sectional van der Waals heterostructures. Our multiscale investigations identify nanoscale substrate undulations as critical nucleation sites for screw dislocations and uncover a multi-screw dislocation-driven (MSDD) growth paradigm, characterized by periodic stress stripes with linear densities approaching ∼10[6] cm[-1]. Furthermore, we establish that dislocation interactions govern stacking sequence reconstruction, while the kinetic competition among multiple screw dislocations determines the ultimate spiral architectures. These insights fundamentally transform our understanding of defect-mediated growth in 2D materials.

NEXI is a gray matter (GM) microstructural model designed to probe brain tissue microstructure in vivo using diffusion MRI. NEXI describes GM as two exchanging Gaussian compartments-neurites, modeled as randomly oriented, infinitely long sticks, and the extracellular space-allowing the estimation of biophysically interpretable parameters related to neurite microstructure and intercompartmental exchange. While modeling cell processes as sticks and each compartment as Gaussian are common assumptions for brain biophysical models of diffusion, neurite structural irregularities and the presence of somas, particularly in GM, may violate them and bias NEXI parameter estimates. Furthermore, the barrier-limited exchange assumed in the Kärger model that underlies NEXI may also be violated in realistic conditions. Therefore, in this work, we evaluate NEXI's accuracy in numerical substrates that contain GM features such as neurite beading, undulation, orientation dispersion, and the presence of somas across a range of membrane permeabilities. Diffusion signals were generated with Monte Carlo simulations of water diffusion and subsequently fitted with NEXI. Overall, NEXI captured trends of exchange time across permeability levels and showed good ability to disentangle exchange effects from other microstructural features. The largest bias in tex was introduced by somas, and in Di by permeability, somas and beading. Otherwise, the structural irregularities evaluated in this study had a relatively modest impact on NEXI estimates. Most bias in NEXI estimates comes from finite SNR. Future work should aim to further improve substrate realism to better represent the complexity of GM morphology.

A new species of deep-sea polynoid, Bathyeliasona oceanxplorer sp. nov., is described from the abyssal plain located in international waters between Christmas Island and the Cocos (Keeling) Islands in the eastern Indian Ocean from a single specimen collected at a depth of 4977 m. The new species is characterised using morphology and molecular data from four genetic markers (COI, 16S rRNA, 18S rRNA, and 28S rRNA). Bathyeliasona oceanxplorer sp. nov. is distinguished from its congeners by a combination of characters, including the possession of 18 segments, slender frontal filaments, the presence of a buccal bulb, and ventral pygidial lobes with weakly undulate margins. This is the first species of Bathyeliasona for which the elytra are described and illustrated. This finding highlights the great value of ROV-based sampling for recovering comparatively intact deep-sea polynoid specimen with most delicate features preserved.

Rapid salinity change (RSC) is becoming more frequent in coastal waters because of extreme rainfall and freshwater discharge, posing increasing challenges to marine bivalves and ecosystems that support. The undulated surf clam (Paphia undulata), an economically important bivalve species in the South China Sea, is frequently exposed to such events, yet its physiological responses to abrupt salinity change remain poorly understood. Here, we exposed P. undulata to salinities rapidly ranging from 5 to 35 for 96 h to assess survival, gill histology, enzymatic responses, and physiological energetics. Survival declined sharply under severe hyposaline conditions (<10), whereas high survival was maintained between salinities of 25 and 30. The LC50 increased from 13.9 PSU at 24 h to 19.7 PSU at 96 h, indicating a time-dependent decline in hyposalinity tolerance during prolonged exposure Histological examination showed gill filament swelling, ciliary erosion, and epithelial damage under low salinity, indicating substantial structural impairment of the gills. Salinity stress also altered ATPase activities, antioxidant responses, and ACP and AKP activities, consistent with changes in ion-transport-related, oxidative, and nonspecific immune processes. In addition, stressful salinity conditions reduced clearance and respiration rates while modifying nitrogen excretion and the O:N ratio, indicating a shift in energy allocation from growth-related processes toward maintenance. Our findings demonstrate that P. undulata may have a narrow tolerance to RSC and provide a physiological basis for assessing the vulnerability of this species to increasingly frequent salinity fluctuations in coastal aquaculture.

A broad range of cellular functions involve transient or persistent changes in the morphology of lipid membranes, from the organellar to the molecular scale. By and large, the thermodynamics of protein-mediated remodeling, which often distort the membrane beyond its thermally accessible undulations, remain to be understood. Molecular Dynamics simulations enhanced by advanced sampling methods are uniquely suited to examine and quantitate these phenomena. Here, we leverage the Multi-Map simulation method to directly quantify how applied lateral tension impacts the energetics of both global and localized membrane perturbations induced extrinsically. We obtain free-energy profiles of curvature and thickness deformations with and without tension, which allow us to test the quadratic approximations of Helfrich-based continuum theories. We find that these continuum models are applicable up to ∼ 20 kBT, beyond which they under-estimate the free-energy cost of bending. However, we find that the effect of tension on these deformations is primarily driven by changes in the projected area of the membrane, and therefore consistent with continuum theory, even beyond 30 kBT. These changes outpace the effects of tension on lipid packing and diffusion, and importantly we find that tension levels preceding rupture (≤ 10 mN/m) do not impede complete lipid mixing. Finally, we investigate the free-energy landscapes of membrane thickness and lipid enrichment with a heterogeneous lipid composition and show that strong enrichment can be sustained even under steady exchange of the constituent lipid molecules.

Soft robotic systems require the integration of compliant and stiff components, yet soft-rigid interfaces remain prone to failure under cyclic deformation due to discrete material junctions. In contrast, biological systems rely on functionally graded materials to distribute stress and optimize performance. Here, we implement hybrid epoxy-acrylate printing (HEAP) to create covalently integrated polymer networks with spatially programmed mechanical properties. HEAP is a multi-wavelength 3D printing strategy that enables control over polymer network architecture within a single resin. We achieve both continuous hardness gradients spanning Shore-A 8 to Shore-D 80. These gradients eliminate weak interfacial boundaries and maintain mechanical integrity under large, repeated strains. Compared to commercial multi-material printing, HEAP reduces interfacial failure by >5× while preserving near-intrinsic stretchability of soft domains. This capability enables single-shot fabrication of soft-rigid robotic systems that undergo large, cyclic deformations, including functionally graded pneumatic bellows with integrated tubing interfaces and spatially programmable deformation modes, bioinspired soft robotic hands with embedded bone-like structures, and an augmented undulating walker that achieves more than a twofold increase in locomotion speed relative to an all-soft counterpart. These results establish a generalizable materials and manufacturing framework for mechanically graded polymer systems, enabling robust soft-rigid integration in robotics and beyond.

Animals with a slender body such as eels progress by propagating body waves; this swimming mode is called anguilliform. Though anguilliform swimming has been studied extensively, its optimality and gait selection principles remain unknown. Here, through model-based optimal gait analysis, we propose that three dimensionless characteristic parameters -- the stride length, muscle mechanical efficiency and environmental force anisotropy -- shape the gait, and they respectively determine a whole or a fraction of body undulation, a more C-shaped or S-shaped body wave, and the overall body undulation amplitude and swim direction. The body(muscle)-fluid properties and the intended swim speed influence the gait via these three. Observed biological gait features, including those of young animals and the counterintuitive ones, are shown to conform, qualitatively, to these principles, suggesting that their gaits may be explained by optimality with respect to the total of fluid and muscle damping power losses, with the latter occupying a small percentage. In addition, the prevailing feature of caudally increased body curvature may be a result of an adjustment to the gait due to the tapered body geometry and/or oncoming fluid vortices. Biological gaits could thus be understood as a composition of aforementioned gait features. Also explained by optimal gaits are the negative correlation between the Strouhal number and the stride length, and the wider range of Strouhal number of anguilliform swimming (0.31-0.93) than that of carangiform swimming (0.2-0.4). The neural signals for muscle activation are also calculated from the model-based analysis to predict control strategies underlying the observed gaits. Our results benefit both the understanding of biological locomotion and the gait planning for bio-inspired underwater vehicles.

Pharmaceutical nanoemulsions are thermodynamically metastable colloidal dispersions whose physical integrity during storage depends on the continuous suppression of flocculation, coalescence, Ostwald ripening, creaming, and phase separation. These destabilization pathways are governed by interfacial phenomena whose molecular-level determinants remain incompletely understood. This review provides a point-to-point mechanistic perspective that connects molecular organization at curved oil-water interfaces to macroscopic stability behavior and predictive formulation design, organized around four themes. First, we examine the interfacial thermodynamic and kinetic foundations, Gibbs-Marangoni restoration, dynamic adsorption-desorption equilibration, molecular packing at nanoscale curvature, and interfacial rheology under shear and dilatational deformation, which determine the mechanical and electrostatic resistance of the stabilizing film. Second, we analyze colloidal interactions beyond the classical DLVO framework, with particular emphasis on hydration, structural, hydrophobic, Asakura-Oosawa depletion, undulation, and bridging forces that dominate droplet behavior at nanometric separations, complementing the Lifshitz-Slyozov-Wagner molecular-transport description of Ostwald ripening. Third, we critically evaluate formulation-driven interfacial modulation: surfactant architecture and concentration, oil-phase composition, ionic environment, excipient selection, and uniquely, the active pharmaceutical ingredient itself as an interfacial participant whose lipophilicity, ionization state, and amphiphilic balance reshape the film it is meant to be carried by. Fourth, we consolidate emerging predictive approaches, interaction-energy profiling, machine-learning-assisted stability modeling, and Stability-by-Design frameworks, as actionable tools for forecasting long-term physical integrity and guiding rational nanoemulsion development. By integrating molecular-level mechanistic understanding with colloidal-scale interaction theory and data-driven prediction, this review establishes a foundation for the design of physically robust pharmaceutical nanoemulsions with predictable shelf-life performance and engineered interfacial architecture.

The genus Angelica L. (Apiaceae) is mainly distributed throughout the Northern Hemisphere and comprises approximately 110 species. Although several molecular phylogenetic studies have been conducted on this genus, the leaf micromorphology has not been sufficiently explored. In this study, we examined the leaf micromorphological characteristics of all the 16 Korean Angelica taxa using light and scanning electron microscopy. The results revealed considerable variation in the morphology of stomatal complexes, epidermal cells, and trichomes. Leaf epidermal cells were generally irregular in shape, exhibiting straight to curved, undulating, or sinuating anticlinal walls, and convex or flat periclinal walls. The leaves were either hypostomatic or amphistomatic, with the former being more frequent. In the amphistomatic taxa, stomata were more densely distributed on the abaxial surface than on the adaxial surface. Anomocytic stomata were predominant, although paracytic stomata were also observed in certain taxa. Simple trichomes were present in all studied taxa, except A. acutiloba. These micromorphological features provide valuable information for species identification and offer important taxonomic insights into this genus. Moreover, the observed variations in leaf micromorphology appeared to be closely related to environmental factors, suggesting that these traits reflect adaptive responses to habitat conditions.