Tissue morphogenesis requires tight coordination between biochemical signaling and mechanical forces that sculpt cells and tissues. While actomyosin networks are well-established force generators, microtubule-based mechanics have recently emerged as crucial contributors to tissue remodeling. Yet, how dynamic microtubules, whose plus ends undergo compression-induced catastrophes that limit their load-bearing capacity, generate forces in vivo remains unclear. Here, we identify Orbit, the Drosophila cytoplasmic linker-associated protein (CLASP) homolog, as a key factor that stabilizes non-centrosomal microtubule plus ends in vivo, enabling them to sustain mechanical loads. In the pupal wing epithelium, these Orbit-stabilized, planar-polarized microtubules are consistent with a role in counteracting actomyosin contractility and promoting tissue elongation. Loss of Orbit increases catastrophe frequency and disrupts epithelial elongation, whereas Orbit overexpression enhances microtubule rescues by suppressing catastrophes, thereby promoting cell anisotropy and tissue extension. Moreover, Orbit-mediated stabilization is sufficient to induce microtubule-dependent, filopodia-like protrusions independent of actin. Together, these findings establish CLASP-dependent microtubule stabilization as a key mechanism linking polymerization dynamics to epithelial morphogenesis.
Machine learning is a powerful tool for modeling complex movements. However, the high cost of acquiring biomechanical data often limits observations and therefore the generalizability of machine learning models. Meanwhile, there is untapped utility in presently published musculoskeletal simulations for informing these predictions. This work evaluated whether a transfer learning model trained on both musculoskeletal simulation and recorded data outperforms a direct learning model trained on recorded experimental data alone. For the transfer learning model, we leveraged a simulation dataset with 6,594 lateral pinch simulations to train a long short-term memory neural network to predict three-component thumb-tip forces from muscle activations. We concatenated this pre-trained neural network with a feedforward architecture and used recorded data (n=12 subjects) to fine-tune the model. The feedforward architecture used the outputs of the long short-term memory neural network, as well as static subject-specific features (e.g., anthropometric measurements). We then trained a direct learning model with a similar architecture using just the recorded data. The transfer learning and direct learning models were parameterized via a random search and underwent five-fold cross-validation. To elucidate the impact of pre-training with simulations, we validated both neural networks and compared their test errors using a leave-out set (n=3 subjects). The transfer learning model outperformed the direct learning model, as suggested by statistically significant lower absolute errors (p = 0.04). Our results suggest the viability of using musculoskeletal simulations to bolster machine learning models that can expand the utility of simulated datasets and potentially improve predictions of real-world biomechanics.
Stokes flow studies are fundamental to advancing medical and industrial technologies, particularly in areas such as drug targeting, cell studies, the optimization of drug carrier vehicles, high viscosity flows, and magnetic particle imaging. While previous research has focused on the motion of obliquely falling cylindrical rods and magnetic particle chains, a broader analytical framework is required to understand more complex particle-fluid migrations. In this paper, we first generalize the two-dimensional motion of an obliquely falling rod in a gravitational field to the three-dimensional motion of an object possessing three mutually perpendicular planes of symmetry falling through a viscous fluid in the Stokes limit. We derive a general formula for the three components of velocity-including both downward and sideways components-for objects of arbitrary orientation and uniform density. These analytical solutions are defined in terms of the object's orientation, specified via Euler angles, and the velocity of the object falling along each of its three principal axes, or the drag coefficient along each of those axes. We give a variety of examples of objects that satisfy this general formula. In addition, we apply the formula to a cuboid for which those velocity components along each of its principal axes have been measured experimentally by other researchers, thus giving both the downward and sideways components for arbitrary orientation. We then analyze the motion in a gradient magnetic field of elongated magnetic particles, such as nanorods and nanoellipsoids, for which the induced magnetic moment is along the long axis of the particle. We discuss the similarities and differences with the gravitational case. By providing a unified framework for predicting the trajectories of these symmetric bodies, this work enhances the understanding of the motion of inertial and magnetic particles under the influence of gravitational and gradient magnetic fields, respectively.
The significance of experimentally observed friction between orthodontic brackets and the connecting archwire for multibracket therapy is still debated. This publication is intended to provide detailed and validated information for the discussion of this issue during the initial alignment and levelling phase. Frictional forces were determined by using in vitro experiments of the simulated levelling of a malpositioned maxillary central incisor. For each experiment a straight archwire was placed in the slots of three aligned brackets. Levelling was simulated by bending the wire using a multistep displacement of the middle bracket. All force and moment components corresponding to each step were recorded at the central and lateral brackets. In vitro frictional forces and the corresponding friction coefficients were determined through direct comparison of experimental results and, additionally, using numerical methods. Different types of conventional orthodontic wires, made of stainless steel [SS] and titanium molybdenum alloy [TMA] were tested. Results indicated that calculated friction coefficients (SS ~0.1; TMA ~0.2) agreed with published reference data. The mesiodistal forces were proportionally more affected (~100% increase) by friction than the levelling forces (10%-20% reduction). Comparison with numerical models demonstrated that carefully dislodging and reinserting the wire is a viable strategy to remove frictional forces. The findings indicate that vertical tooth movement was only moderately influenced by friction when conventional SS or TMA wires were used. Clinically, the results suggest that an effective way to reduce friction may be re-opening wire ligatures or using passive self-ligating brackets. ZIELSETZUNG: Die Bedeutung der experimentell beobachteten Reibung zwischen kieferorthopädischen Brackets und dem verbindenden Bogendraht für die Multibracket-Therapie ist nach wie vor Gegenstand von Diskussionen. Diese Veröffentlichung soll detaillierte und validierte Informationen für die Erörterung dieser Frage während der anfänglichen Ausrichtungs- und Nivellierungsphase liefern. Die Reibungskräfte wurden anhand von In-vitro-Experimenten zur simulierten Nivellierung eines fehlgestellten oberen mittleren Schneidezahns ermittelt. Bei jedem Experiment wurde ein gerader Bogendraht in die Schlitze von drei nebeneinander angeordneten Brackets eingelegt. Die Nivellierung wurde durch Biegen des Drahtes mittels einer mehrstufigen Verschiebung des mittleren Brackets simuliert. Bei jedem Schritt wurden alle Kraft- und Momentkomponenten am mittleren und an den seitlichen Brackets aufgezeichnet. Die In-vitro-Reibungskräfte und die entsprechenden Reibungskoeffizienten wurden durch direkten Vergleich der Versuchsergebnisse sowie zusätzlich unter Verwendung numerischer Methoden ermittelt. Getestet wurden verschiedene Arten von konventionellen, kieferorthopädischen Drähten aus Edelstahl [SS] und Titan-Molybdän-Legierung [TMA]. Die Ergebnisse zeigten, dass die berechneten Reibungskoeffizienten (SS ~0,1; TMA ~0,2) mit veröffentlichten Referenzdaten übereinstimmten. Die mesiodistalen Kräfte wurden proportional stärker (~100% Anstieg) durch Reibung beeinflusst als die Nivellierungskräfte (10–20% Abnahme). Der Vergleich mit numerischen Modellen zeigte, dass das vorsichtige Lösen und erneute Einsetzen des Drahtes eine praktikable Strategie zur Beseitigung von Reibungskräften darstellt. Die Ergebnisse deuten darauf hin, dass die vertikale Zahnbewegung bei Verwendung herkömmlicher SS- oder TMA-Drähte nur mäßig durch Reibung beeinflusst wurde. Klinisch legen die Ergebnisse nahe, dass das erneute Öffnen von Drahtligaturen oder die Verwendung passiver, selbstligierender Brackets ein wirksames Mittel zur Verringerung der Reibung sein könnte.
Nanofiltration (NF) is an effective barrier for removing nanoplastics (NPs) from water. However, NPs can deposit on the membrane surface and remain even after backwash, altering surface properties and reducing filtration performance. In this study, laser-induced breakdown detection (LIBD) is coupled in-line with a bench-scale NF system to quantify the deposition and release of polystyrene (PS) particles and weathered NPs at environmentally relevant concentrations (1-500 µg/L; 107-109 particles/mL). Particle deposition during filtration and release during backwash were successfully determined in all experiments, supported by theoretical analysis of the interplay between hydrodynamic and intermolecular forces. At permeate fluxes higher than 100 L/m2.h, 50-100% of PS particles were deposited by the end of filtration experiments, forming cake layers up to 9 particle diameters thick. In contrast, weak permeate drag forces corresponding to fluxes below 50 L/m2.h (i.e., just beyond the critical flux) resulted in insignificant deposition. Backwash fluxes from 15 to 57 L/m2.h exhibited negligible differences in the release of deposited particles owing to only a little increase in backwash drag force. Two mechanisms were observed for the release of NPs during backwash: i) complete release in small circular areas (diameter ≤2 µm) for thin deposits and ii) fracturing of the cake layer for thick deposits. For weathered NPs, irreversible deposition on the membrane surface was observed, although potential particle aggregation and polydispersity must be accounted for to obtain truly quantitative results. The successful quantification of particle deposition and release showcases LIBD as an effective method for fundamental investigations on NP transport during membrane filtration.
Labiaplasty has expanded worldwide, provoking debate over whether it reflects women's liberation, reinforces objectifying beauty norms, or medicalizes normal vulvar variation. Clinicians lack integrative guidance linking outcomes with feminist ethical analysis. To synthesize evidence on labiaplasty through feminist frameworks of liberation, objectification, and medicalization; evaluate functional, sexual, and psychological outcomes; and propose a clinical framework centered on relational autonomy and non-pathologizing education. A narrative review of peer-reviewed literature (2002-2025) was conducted using PubMed and Google Scholar, with screening of relevance based on predefined thematic domains including motivations, outcomes, sociocultural influences, and ethics. Empirical studies on motivations, outcomes, and educational interventions were included as clinical evidence, while feminist theoretical and ethical analyses were used for interpretive synthesis. Data were synthesized thematically along three axes: Liberation/autonomy, objectification/sociocultural pressure, and medicalization of normal anatomy. Utilization of labiaplasty has increased markedly, including in adolescents, although population-level rates remain underreported. Patients commonly endorse overlapping functional, aesthetic, and psychosexual motivations; many have labial dimensions within published normative ranges. Prospective cohorts and meta-analyses show high satisfaction and improvement in pain, functional symptoms, genital self-image, and sexual function, with low rates of major complications or long-term sensory loss when nerve-sparing techniques are used. However, elevated body-image distress and clinically significant body dysmorphic disorder (BDD) occur in a substantial subset. Media, pornography, and clinical marketing narrow perceptions of "normality," while language and diagnostic labels can pathologize benign variation. Labiaplasty sits at the intersection of liberation, objectification, and medicalization: Many patients experience benefit, yet decisions are shaped by sociocultural forces that constrain autonomy and recast normal anatomy as abnormal. The proposed L.A.B.I.A. framework (legal safeguards, autonomy assessment, body-image/BDD screening, informed consent and non-pathologizing education, and aftercare) offers clinicians an ethically grounded approach to counseling, patient selection, and follow-up while underscoring the need for education and policy that normalize vulvar diversity.
Three new studies show that a single receptor-ligand pair, Teneurin-3 and Latrophilin-2, directs long-range circuit assembly across diverse brain regions through opposing forces of attraction and repulsion. The same two molecules, reused again and again, wire the brain.
In this study, the polygonatum sibiricum polysaccharide (PSP) was extracted using the deep eutectic solvent (DES) and added into soybean protein isolate (SPI) to prepare the SPI - PSP gel. Afterwards, the SPI - PSP gel properties were analyzed to explore how the PSP affected the gel properties and the gelation mechanism. When the PSP addition was from 0% to 2.5% (w/v, g/100 mL), the gel hardness increased from (18.70 ± 2.10) g to (36.10 ± 3.22) g. The gel consistency was enhanced, but the gel flow behavior was inhibited. Besides, the gel water-holding capacity rose from (83.56 ± 1.13) % to (89.80 ± 1.28) %, and the gel thermal stability was enhanced due to the PSP addition. The free sulfhydryl group, the protein structure changes and the intermolecular forces in the SPI - PSP gels were evaluated for exploring the gel formation mechanisms. It was found that the free sulfhydryl group content increased from (2.77 ± 0.01) to (3.40 ± 0.00) μmol/100 mg. The PSP significantly diminished α-helix and β-turn contents and elevated β-sheet content of the SPI secondary structure. So, more hydrogen bonding was formed to improve the SPI - PSP gel formation due to the changes of the SPI secondary structure. It was provided a basic to adjusting the gel properties according the polysaccharide addition.
Focal adhesions are central structures that allow cells to sense and respond to extracellular mechanical cues, yet traditional interaction-based models cannot fully explain their efficient protein enrichment, rapid turnover, and strong mechanical sensitivity. Recent studies highlight liquid-liquid phase separation (LLPS) as a novel physicochemical mechanism that reshapes our understanding of focal adhesion organization and function. This review summarizes current mechanisms of focal adhesion-mediated mechanosensing, with a focus on the emerging role of phase separation. Several core focal adhesion proteins, such as talin and paxillin, can form biomolecular condensates whose assembly is regulated by mechanical forces and post-translational modifications. These condensates offer a mechanism for converting mechanical inputs into biochemical signals. We highlight how phase separation contributes to focal adhesion assembly, maturation, cytoskeletal regulation, and dynamic turnover. The concept of LLPS provides a unified framework for understanding focal adhesion behavior and advances our understanding of cellular mechanosensing.
Polychlorinated Biphenyls (PCBs) are persistent organic pollutants in the environment. With high lipophilicity, PCBs are easily accumulated in the brain, finally leading to neurotoxicity. The underlying neurotoxicity mechanism of PCBs remains poorly understood and requires urgent investigation. The neurotransmitter system has been identified as a potential target of PCB-involved neurotoxicity. Current research on the neurotoxicity mechanism of PCBs predominantly focuses on single target. Due to the high complexity of the brain, the disorder of synaptic transmission triggered by environmental pollutants is highly complicated, and the corresponding mechanisms are likely to involve multi-targets. Here, we focused on two highly correlated components of the dopaminergic system-the dopamine transporter (DAT) and dopamine receptor (DR), to investigate whether there is a synergetic effect between them. By combining multiple computational methods and experimental assays, this study elucidated that DAT was a potential target of neurotoxicity for PCBs in the dopaminergic system, whereas it was highly unlikely for DR to bind PCBs. The computational results indicated that the affinity of the pentachloro biphenyl was higher than the tetrachloro biphenyl. The Van der Waals and π-π interactions were the main driving forces for PCBs binding to DAT. The decomposition energy confirmed that the key residues involved in the ligand binding were converged to Val120, Tyr124, and Phe325 for most of the tested PCBs. Our findings not only provide a detailed and plausible molecular mechanism of PCBs' neurotoxicity, but also are useful for the rational drug design to fight diverse CNS disorders and other diseases involving DAT.
This study explored the impact of varying cassava starch (CS) levels on the rheological and textural attributes and printability of sodium caseinate-cassava starch (NaCas-CS) composite emulsion gels. Increasing the CS content led to higher apparent viscosity and gel hardness, reduced fluidity, and promoted the formation of a tighter network. The composite containing 12% CS exhibited the best printing performance and dimensional accuracy, suggesting that an optimal balance of viscosity, hardness, and flow behavior is essential for successful 3D printing. Furthermore, increasing CS caused a leftward shift in relaxation time, indicating restricted water mobility and enhanced water-binding capacity. Microstructural analysis confirmed that elevated CS contents facilitated the development of a denser network. FT-IR analysis supported that the enhanced emulsion gel properties were driven by strengthened intermolecular interactions between CS and NaCas, including hydrogen bonding and electrostatic forces. These findings guide starch-enhanced 3D printability of protein gels and support starch-protein composites in food applications.
Engineering organized microvascular networks remains a critical challenge in tissue engineering and regenerative medicine. While biochemical approaches for patterning angiogenesis via growth factor delivery have shown promise, their inability to pattern sustained growth factors with spatiotemporal control limits effectiveness. Here, we demonstrate that dynamically patterned mechanical forces enable precise spatiotemporal control over angiogenic sprouting. We developed a magnetically actuated human vessel-on-a-chip platform that integrates a perfusable endothelialized microchannel within a collagen matrix and allows noninvasive and tunable mechanical stimulation across three spatial dimensions and time (4D). Using an automated 3-axis actuator, we systematically investigated how strain magnitude, frequency, and direction modulate endothelial cell behavior and vessel morphogenesis. Dynamic mechanical stimulation at physiological strain magnitudes (5 to 15%) enhanced endothelial alignment and barrier function while promoting angiogenesis in a strain magnitude-dependent manner: lower dynamic strain (5%) maximized sprout initiation, whereas higher dynamic strain (15%) promoted elongation of sprouts. Sequential reorientation of strain direction reprogrammed sprouting trajectories along X, Y, and Z directions, generating complex sprout geometries such as L-shaped branches. RNA sequencing revealed mechanically induced transcriptional profiles distinct from unstimulated controls, characterized by upregulation of genes associated with angiogenesis, mechanotransduction, and extracellular matrix remodeling. Functional perturbation of PIEZO1 reduced strain-induced sprouting without altering barrier function, indicating that dynamic mechanical stimulation engages multiple mechanotransduction pathways to regulate angiogenesis. Collectively, these findings establish a strategy for spatiotemporally controlled angiogenesis through 4D force patterning to program vascular morphogenesis while preserving function. This approach provides a foundation for engineering hierarchically organized vascular networks for tissue regeneration.
Preclinical assessment of patient-specific mandibular reconstruction plates relies on bench testing and computational modeling, yet existing setups are typically designed on practical grounds without a structured method to ensure their mechanical relevance to the intended clinical context of use (COU). This study proposes and demonstrates a methodology for constructing and assessing a validation domain with experimental and computational components for patient-specific fibula free flap mandibular reconstruction. A clinical reference finite element model (M-COU) representing the reconstructed mandible under physiological clenching conditions was used as an active design tool to derive the validation setup. Parameters were identified through analytical calibration of M-COU reaction forces and refined via a design-of-experiments procedure. The resulting setup was implemented as two coordinated components: a physical validation platform (R-VAL) enabling bench testing of the actual reconstruction plate, and a validation computational model (M-VAL) reproducing the same setting numerically. The resulting setup preserved the dominant mechanical features of the clinical scenario. In consistency analysis against M-COU, M-VAL achieved R2 = 0.75, substantially exceeding literature-based benchmark configurations (R2 = 0.27 and 0.40), and was the only configuration to preserve the clinically relevant stress distribution at the mandibular angle. Comparison between M-VAL and R-VAL showed close agreement in initial structural stiffness (0.6% difference) and local strain distribution (R2 = 0.93; RMSE = 10.9%). The proposed methodology provides a transferable framework for constructing validation domains that are simultaneously experimentally feasible, mechanically interpretable, and grounded in a defined clinical COU.
Hepatic fibrosis is a critical stage in the progression from chronic liver injury to hepatocellular carcinoma (HCC), yet effective therapeutic options remain limited. Jianpi Huayu Decoction (JPHY) has been used clinically in patients with HCC accompanied by hepatic fibrosis, but its anti-fibrotic mechanisms remain unclear. This study evaluated the anti-fibrotic effects of JPHY and explored potential links between metabolic regulation and tissue mechanics. A carbon tetrachloride (CCl₄)-induced mouse model of hepatic fibrosis and TGF-β-activated hepatic stellate cells were used to assess the anti-fibrotic effects of JPHY. Interventions included JPHY, the PPARα agonist fenofibrate, and their combination. Multi-scale analyses were performed, including transcriptomic profiling, atomic force microscopy for local tissue stiffness measurement, molecular and cellular assays, and molecular docking and dynamics simulations. Clinical relevance was evaluated using human liver tissues. An orthotopic HCC model established in a fibrotic background was used to evaluate the association between JPHY treatment and tumor progression. JPHY attenuated CCl4-induced hepatic fibrosis in mice, as evidenced by reduced collagen deposition, decreased liver stiffness, and improved liver function parameters. Mechanistic analyses revealed that these effects were associated with activation of the PPARα-mediated lipid metabolic pathway and suppression of ROCK-dependent mechanical signaling. Combined treatment with JPHY and a PPARα agonist resulted in greater improvements in anti-fibrotic markers than either treatment alone. Exploratory clinical validation suggested an inverse association between hepatic PPARα expression and fibrosis severity. In a fibrosis-associated HCC model, JPHY also suppressed tumor progression, accompanied by alterations in arachidonic acid metabolism. JPHY alleviates hepatic fibrosis through coordinated modulation of PPARα-mediated metabolic remodeling and ROCK-dependent mechanical signaling, thereby reducing liver stiffness and extracellular matrix accumulation, with potential implications for mitigating fibrosis-associated HCC progression.
Sodium glucose cotransporter-2 inhibitors (SGLT2is) may influence erythropoiesis, but intra-class differences and evidence certainty remain unclear. We evaluated the comparative effects of individual drugs on hematological parameters. We searched electronic databases for randomized controlled trials comparing any SGLT2i with placebo, standard of care, or another SGLT2i. Outcomes included hemoglobin, hematocrit, red blood cell (RBC) count, erythropoietin, and anemia risk. Pooled estimates were calculated using standardized mean difference (SMD) or odds ratio (OR) with 95% confidence intervals (CI). Certainty of evidence was assessed. One hundred thirty-six studies (102,882 participants) were included. As a class, SGLT2is significantly increased post-intervention hemoglobin (SMD 0.42 [95% CI 0.33, 0.51]), change-from-baseline hemoglobin (SMD 0.87 [0.65, 1.10]), post-intervention hematocrit (SMD 0.53 [0.44, 0.62]), change-from-baseline hematocrit (SMD 0.91 [0.72, 1.10]), post-intervention RBC count (SMD 0.56 [0.37, 0.75]), change-from-baseline RBC count (SMD 0.94 [0.48, 1.39]), and post-intervention erythropoietin (SMD 0.26 [0.01, 0.52]), but did not reduce anemia risk (OR 0.93 [0.76, 1.14]). Among individual drugs, ertugliflozin showed the largest post-intervention hemoglobin increase, and canagliflozin showed the largest change-from-baseline hemoglobin increase. Evidence certainty was low to very low. SGLT2is consistently increase hemoglobin, hematocrit, RBC count, and erythropoietin, with intra-class differences observed for specific outcomes. However, low to very low certainty evidence precludes definitive comparative recommendations.
Uveal melanoma (UM) is a biologically distinct melanoma subtype in which excellent local tumor control contrasts sharply with a high risk of delayed metastases. The frequent occurrence of distant relapse months to years after index local therapy suggests systemic dissemination early in the disease course. Inadvertently, many patients harbor minimal residual disease (MRD), comprising microscopic tumor cell populations that persist after primary tumor treatment and are undetectable by conventional imaging techniques. Historically, UM management has focused on local tumor eradication followed by surveillance, however, better understanding of the clinical trajectory of UM coupled with advances in systemic therapeutics have generated increasing interest in perioperative systemic approaches. Neoadjuvant therapy provides the opportunity to downsize the primary tumor, eliminate occult micrometastatic disease, dynamically evaluate disease biology, and inform further therapeutic decision-making. Adjuvant approaches aim to suppress or eradicate MRD following local control in patients at elevated risk of relapse. Although current evidence remains investigational or early-phase, perioperative systemic therapy represents an important research frontier in UM that holds the potential to reshape its therapeutic paradigm. Herein, we comprehensively synthesize the biological rationale, the latest data, and the ongoing clinical trials supporting perioperative systemic therapy, and discuss the emerging role of circulating tumor DNA (ctDNA) in the management of UM.
Emulsion gels have great potential for application in fat substitutes. Sunflower oil body (SFOB)-κ-carrageenan (CG) emulsion gels were fabricated, and the synergistic effects of SFOB extraction pH, oil phase volume fraction, and CG concentration on their gelation behavior, multiscale structure, and functional properties were systematically investigated. Results showed three variables significantly regulated the interfacial protein composition of SFOB, the cross-linking density of the gel network, and the binding force between SFOB and CG. The optimal emulsion gel was formulated with 0.9% CG and 20% oil phase volume fraction (from SFOB extracted at pH 7.0), which exhibited a compact and uniform three-dimensional network structure, superior WHC and minimal cooking loss. Furthermore, FTIR and SARS revealed that disulfide and hydrogen bonds contributed to the stabilization of the gel structure. Overall, this CG/SFOB emulsion gel represents a promising fat substitute and provides a novel approach for developing low-fat food products.
Dynamics associated with the expanding Hadley Circulation (HC) are gaining attention owing to their far-reaching consequences on tropical and subtropical weather and climate. In the present communication, the co-variability of ascending and descending regions of the HC at regional scales is investigated. The results from four decades of ERA-5 reanalysis emphatically show that the ascending and descending regions of the HC move in tandem with profound zonal asymmetry in their degree of co-variability, and their long-term trends show similar signs with notable differences in magnitude. In more than half of the longitudinal sectors, the relative movement between the ascending and descending boundaries of each hemisphere is in unison. At this juncture, where there are debates on the causative mechanism for the observed expansion of HC as well as their zonal asymmetries, the present results provide new insights into the regional HC dynamics by emphasizing the coherent variations of ascending and descending regions of the HC at regional scales for the first time. The results discussed in the study will be useful for identifying differences in the regional forcing of HC expansion and for quantifying the regional expansion rates of both ascending and descending regions of the HC.
Subterranean ecosystems play a pivotal role in shaping diversification processes, particularly among invertebrates, which frequently exhibit convergent troglomorphic traits such as ocular reduction and elongation of appendages. Among crustaceans, amphipods demonstrate exceptional adaptive potential for colonizing hypogean habitats, revealing an often underappreciated reservoir of subterranean biodiversity. In the semiarid Caatinga of northeastern Brazil, the Jandaíra Formation constitutes an extensive Cretaceous limestone system, harboring more than 1,400 documented caves and representing a critical hotspot for stygobiotic taxa. Building on this insight, we expand the known range of Seborgia within the Jandaíra Formation and describe a single new troglobitic species from a spatially isolated cave system. This species is readily diagnosable by distinct morphological characters of the gnathopods, uropods, and telson, and its occurrence in strict allopatry is consistent with diversification driven by subterranean vicariance. Its highly restricted distribution highlights the role of hydrogeological isolation and habitat fragmentation as key evolutionary forces shaping subterranean diversity in this region. Notably, the newly described species occurs in a cave in the Furna Feia National Park, highlighting the importance of protected areas for the conservation of subterranean ecosystems and their unique biodiversity.
The nucleation kinetics activated by ultrasonic vibrations in ultrasonics assisted directed energy deposition (UADED) remains unknown and poses a challenge. The ultrasonic volume force and heat enhancement terms are incorporated to the ultrasonic-induced heat-flow-microstructure coupling model to establish the new nucleation kinetics model for better controlling of microstructures in UADED. Mechanism on the nucleation and grain evolutions is proposed to clarify the nucleation kinetics between the ultrasonic features and the microstructural evolutions in UADED. The heat input is increased by 27.3 W/m3 caused by ultrasonic vibrations induced heat enhancement term, and the flow velocity is increased by 43.3% caused by ultrasonic vibrations induced kinetic energy density in UADED. The comprehensive role of the combination of ultrasonic-induced heat input and flow behaviors can lead to an increase in the thermal undercooling by 40.7 K. The nucleation rate is then increased by 68.6% in comparison with the traditional DED, leading to the decrease of the average grain size from 220 μm to 130 μm. The proposed NKT and designed experimental platform are meaningful for the microstructure control in AM.