Acute severe hypoxia reduces systemic oxygen availability and may impose different constraints on cerebral and muscular oxygenation. We tested whether the prefrontal cortex (PFC) and vastus lateralis (VL) exhibit distinct oxygenation patterns during exercise by combining dual-site NIRS with phase-plane vector analysis of oxyhemoglobin (HbO2) and deoxyhemoglobin (HHb). Twelve physically active adults (11 men, 1 woman; VO2max: 52.03 ± 9.84 mL·kg-1·min-1) performed maximal incremental exercise in normobaric normoxia and severe normobaric hypoxia (FiO2 = 11%, ~5000 m equivalent). Responses were compared at lactate-matched submaximal intensities (2 and 4 mmol·L-1) and peak exercise. At rest, hypoxia reduced tissue saturation index (TSI) more in PFC than VL (10.82 ± 2.48 vs. 3.37 ± 4.75 percentage points). During, hemoglobin-derived variables mainly reflected exercise intensity and regional differences. Phase-plane angle K differed between hypoxia and normoxia in the PFC already at 2 mmol·L-1 (118.11 ± 35.73° vs. -15.41 ± 110.08°; p < 0.001), whereas mean VL K remained within the 90-180° sector across intensities and conditions (116-133°), without significant between-condition differences. No between-condition difference in PFC K was detected at peak exercise. These findings describe regional oxygenation responses to severe hypoxia, with condition-dependent differences in the submaximal PFC response. These regional oxygenation responses may partly reflect hypocapnia-related constraints on prefrontal perfusion and compensatory vasodilation in exercising muscle, although K does not directly quantify blood flow or oxygen extraction and its interpretation warrants caution when PFC vector magnitudes are small.

Conventional intraoperative gap assessment is performed in standardized reference positions that do not replicate many functional postures patients assume during daily activities. Physiologic lateral compartment opening becomes most apparent in postures combining flexion, hip external rotation, and relative varus alignment, such as sitting cross-legged, and shoe or sock application. The Figure-of-4 position reproduces this combination intraoperatively. The purpose of this study was to describe the Figure-of-4 maneuver as an intraoperative positional assessment during robotic total knee arthroplasty (rTKA) and quantitatively characterize compartment behavior during its execution using standardized robotic measurements.

This study presents a self-supervised, motion-resolved reconstruction framework for high-resolution, free-breathing pulmonary magnetic resonance imaging (MRI) using a three-dimensional Gaussian representation (3DGS). The proposed method leverages 3DGS to address the challenges of motion-resolved 3D isotropic pulmonary MRI reconstruction by enabling smooth interpolation across voxels for continuous spatial representation across different respiratory motion states. Pulmonary MRI data are acquired using a golden-angle radial sampling trajectory, with respiratory motion signals extracted from the center of k-space in each radial spoke. Based on the DC self-gated respiratory signal, the k-space data are sorted into multiple respiratory motion states. A 3DGS framework is then applied to reconstruct a reference image volume from the first motion state. Subsequently, a learnable low-rank sparse motion model is trained to estimate deformation vector fields (DVFs) from the canonical state to the other motion states, which are then used to generate images for the remaining motion states by spatially transforming the reference volume. The proposed reconstruction pipeline is evaluated on six subjects and benchmarked against three state-of-the-art MRI motion-resolved reconstruction methods. The experimental findings demonstrate that the proposed framework effectively reconstructs high-resolution, motion-resolved pulmonary MR images. Compared with existing approaches, it achieves superior image quality, as reflected by higher signal-to-noise ratio and contrast-to-noise ratio. The proposed self-supervised 3DGS-based reconstruction method enables pulmonary MRI to be resolved into distinct respiratory states with isotropic spatial resolution, highlighting its promise for clinical pulmonary MRI.

Aliovalent metal substitution provides a precise means of engineering defects in Zr-based metal-organic frameworks (Zr-MOFs). However, previous studies have focused largely on In-based frameworks, and sulfur-containing conjugated Zr-MOFs remain underexplored. Herein, a series of gradient In3+-substituted Zr-DTD MOFs (denoted In@1-X, X = 5-40 mol%) (H2DTD = 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid) was solvothermally prepared; valence mismatch between In3+ and Zr4+ spontaneously generates tunable oxygen vacancies on Zr₆ clusters. Comprehensive characterization confirmed that moderate In3+ doping (10 mol%) optimized both porosity and hydrophilicity, yielding a Brunauer-Emmett-Teller (BET) surface area of 1032 m2⋅g-1, a water contact angle of 56.8°, and a water uptake of 358 mg⋅g-1 at P/P0 = 0.9. Electrochemical measurements revealed a volcano-shaped relationship between defect density and proton conductivity. At 100 °C and 98% relative humidity (RH), In@1-10% exhibited a conductivity of 1.4 × 10-2 S⋅cm-1, approximately twice that of pristine Zr-DTD and maintained conductivities on the order of 10-2 S⋅cm-1 at 100 °C over 68-93% RH. Arrhenius analysis indicated a transition from Grotthuss to Vehicle transport upon heating in the moderately substituted samples, whereas excessive In loading (30 or 40 mol%) disrupted the H-bonding network and reduced conductivity. All samples retained good water, acid-base, thermal, and electrochemical stability. These findings establish aliovalent substitution as a straightforward strategy for tuning pore structure, surface affinity, and proton transport in Zr-MOFs through controlled node-defect engineering.

Accurate assessment of cardiac mechanics and hemodynamics is important for understanding cardiac dysfunction and disease progression. However, conventional echocardiographic metrics primarily reflect global mechanical performance and provide limited insight into intraventricular flow dynamics. Ultrafast vector Doppler imaging (VDI) enables contrast-agent-free quantification of intracardiac flow, but acquisition-related reproducibility is difficult to isolate clinically because physiological conditions, acoustic windows, and probe orientation may vary simultaneously. Murine imaging permits repeated acquisitions under standardized conditions, enabling controlled assessment of cycle-to-cycle and imaging-plane variability, and providing a platform for systematic evaluation of VDI in the heart. We established a standardized framework for intraventricular flow quantification using ultrafast VDI and evaluated its reproducibility in a cardiomyocyte-specific Tafazzin knockout (Taz-cKO) murine model of dilated cardiomyopathy (DCM). Nine male mice (n = 3 Taz-cKO and n = 6 controls), aged 12-13 months, were studied. Cycle-to-cycle variability (beat-to-beat variation) averaged ~17.5%, whereas between-acquisition variability was higher (~25.5%), reflecting differences in imaging-plane orientation. Despite this variability, VDI-derived parameters differentiated control and DCM mice, with reduced kinetic energy and vector concentration, increased flow angle difference, and reduced vorticity magnitude during systole. Correlations with conventional echocardiographic indices ranged from weak to strong and varied by parameter, region, and cardiac phase, reflecting heterogeneous associations across metrics. These findings indicate that VDI-derived parameters capture complementary aspects of intraventricular flow not fully reflected by conventional measures of cardiac function. Overall, these results establish the reproducibility and physiological relevance of ultrafast VDI and support its potential for longitudinal and translational studies of cardiac flow dynamics.

Bound states in the continuum (BICs) have long been recognized as topological singularities of light, yet their descriptions have relied solely on scalar topological charges that trace a polarization angle rotation, leaving their true vectorial topology unexplored. Here, we apply the concept of a vectorial topological charge (VTC) to BICs, resolving this fundamental limitation by capturing the full set of winding numbers of (S_{1}, S_{2}, S_{3}) axes on the Poincaré sphere. Using bilayer photonic crystal slabs as a model system, we reveal that nontrivial VTCs can be manifested through pseudopolarization singularity generated by BICs within the perturbation parameter space. Intriguingly, such a VTC further links BICs to counterrotating phase singularities in the upward and downward radiation channels-an effect invisible in scalar frameworks. Moreover, the multicomponent nature of VTCs drives a BIC to split into multiple pairs of half-integer pseudopolarization singularities under symmetry breaking, rather than merely forming a pair of circular pseudopolarization states, thereby defying the conventional rules of topological charge evolution. Our findings reveal a richer vectorial topology that enables control of BICs beyond scalar descriptions.

Twisted MoTe_{2} hosts intriguing correlated quantum phenomena including the fractional quantum anomalous Hall effect in twisted bilayer (t-BL) MoTe_{2} near 3.7°, which is sensitive to the twist angle and moiré superlattices. Here, we directly visualize the twist-angle-modulated electronic structure of t-BL and twisted double-bilayer (t-DBL) MoTe_{2} near this critical angle. We find that the moiré superlattice not only modifies the relative energy between the Γ and K valleys in t-BL MoTe_{2}, but also strongly reconstructs the Γ valley for both t-BL and t-DBL MoTe_{2}. Specifically, the deep p_{z}-derived band at Γ exhibits a distinct splitting that systematically varies with increasing twist angle. Theoretical analysis suggests that this modulation arises from the twist-angle-dependent lattice relaxation, especially interfacial corrugations. Our work directly visualizes the moiré-modulated electronic structure and provides key spectroscopic information of lattice relaxation and interlayer interactions underlying the physics of twisted MoTe_{2}.

Conventional print is noninteractive, whereas modern electronic displays, even with improved energy efficiency, require continuous power input and generate electronic waste. Here, we report morphing polymeric voxels based on liquid crystal that enable seamless and reversible information display without onboard electrical power or integrated circuitry. Each voxel exhibits programmable dual birefringence arising from geometry-defined structural anisotropy and mesogen-defined material anisotropy. By mapping laser-writing angle and power, two distinct images are encoded within a single array. Mechanical deformation induces voxel buckling and hybrid director fields, reversibly switching brightness dominance between the two birefringence channels. This deformation-driven mechanism enables reversible transitions between preencoded images. Comprising only polymers and relying on passive optical modulation, the platform establishes a sustainable route toward circuit-free dynamic displays.