Search Results (2,374)

Multi-view optical reconstruction supports spacecraft inspection, target characterization, and analysis from viewpoints not observed during image acquisition. For time-sensitive space situational awareness, such reconstruction must balance fidelity with the time required to build and render the scene representation. Three-dimensional Gaussian splatting (3DGS) provides efficient novel-view rendering, but its general-purpose initialization and densification do not account for the strong spatial imbalance of spacecraft imagery, where a compact and structurally complex target is surrounded by a largely uninformative background. This mismatch can allocate computation to weakly supported regions, limit the reconstruction of thin structures and object boundaries, and enlarge the representation without a corresponding gain in fidelity. We propose SpaceFast-GS, a foreground-guided framework that introduces RGB-derived target evidence at three successive stages. Foreground-guided allocation (FGA) constructs relaxed multi-view support and places the initial Gaussian population directly in image-supported target regions, reducing the corrective growth required after generic initialization. Object- and boundary-aware refinement (OBR) retains full-image photometric supervision while increasing the contribution of spacecraft regions and silhouette transitions. Guided population control (GPC) combines optimization gradients with support confidence, thin-support evidence, and projected reconstruction residuals to prioritize densification toward a target population and avoid unnecessary primitive growth. All target evidence is obtained from the training RGB images and calibrated cameras, without external segmentation or pretrained reconstruction. On NASA3D Standard-29, SpaceFast-GS ranks second across five reconstruction measures and achieves $41.357\pm 0.015$ dB full-image PSNR in 159.4 s at 932.1 FPS. Relative to standard 3DGS, this represents a 32.3% reduction in training time and a 3.41-fold increase in rendering throughput; stage-wise ablations further verify the contribution of FGA, OBR, and GPC. These results show that coordinating Gaussian allocation, refinement, and population growth with foreground evidence can improve reconstruction turnaround and rendering efficiency while retaining competitive spacecraft reconstruction quality. Full article

Lead-free palladium halides containing square-planar coordination units provide a distinctive platform for investigating light-matter interactions, yet their spectroscopic behavior and thin-film photoresponse remain largely unexplored. Herein, we report a systematic investigation of Cs₂PdCl₄·H₂O, synthesized as both nanorods and single crystals, covering its structural, spectroscopic, electronic, and photoresponsive properties. Single-crystal X-ray diffraction confirms that the monohydrate crystallizes in the orthorhombic Cmcm space group with discrete square-planar [PdCl₄]²⁻ units. Powder X-ray diffraction verifies that the nanorods adopt the same crystalline phase and retain their principal diffraction features after two months of ambient storage. X-ray photoelectron spectroscopy confirms the Pd(II) valence state, and optical measurements determine a direct bandgap of 2.32 eV. Temperature-dependent and time-resolved photoluminescence reveal a low-temperature emission blueshift, enhanced emission intensity, and prolonged carrier decay, attributable to suppressed non-radiative relaxation and contributions from multiple emissive states. Density functional theory calculations based on the experimentally determined monohydrate structure show that the band-edge states are dominated by Cl 3p and Pd 4d orbitals. Thermally deposited Cs₂PdCl₄·H₂O-derived films deliver reproducible visible-light photocurrent switching across 397–564 nm and retain 71% of their initial response after 504 h under nitrogen. These findings establish Cs₂PdCl₄·H₂O as a visible-light-responsive lead-free palladium halide and provide a basis for future exploration in optoelectronic sensing. Full article

This work presents an incremental zoom analog-to-digital converter (ADC) readout integrated circuit (IC) and field-programmable gate array (FPGA)-based digital calibration system for high-precision capacitive micro electro-mechanical system (MEMS) pressure sensors, aimed at enhancing pressure readout resolution, pressure measurement accuracy, and long-term output stability. In the readout IC, the zoom ADC employs coarse-fine quantization, achieving high readout accuracy while relaxing requirements on integrator output swing and front-end linearity. On the digital side, a sparrow-search-algorithm-optimized Gaussian process regression (SSA-GPR) model constructs a nonlinear pressure–temperature mapping with limited calibration samples, while a segmented aging-compensation scheme based on dual-channel periodic self-test dynamically corrects aging-induced offset and sensitivity drifts. Together, these three techniques form a complete signal-conditioning chain addressing weak capacitance variation readout, pressure–temperature coupling, and long-term drift. Measured results show 0.11 Pa_RMS output root mean square (RMS) noise under a 205.2 ms conversion time, 37.44 Pa mean absolute error over −40 °C to 85 °C and 30 kPa to 120 kPa, and ±30 Pa residual error after 85 °C/1000 h aging, confirming the effectiveness of the proposed readout IC and digital calibration system. Full article

Polymetallic nanoclusters (NCs) offer a powerful route to brighter and more tunable luminescent materials, while biopolymer ligands provide additional advantages for sensing and bioimaging. However, the mechanisms responsible for luminescence enhancement remain poorly understood, particularly for DNA- and protein-protected NCs. Here, we critically review the relationship between metal composition, cluster structure, ligand environment, and excited-state dynamics in luminescent polymetallic NCs. Rather than treating alloying as a single “synergistic” effect, we distinguish three recurrent contributions to enhanced emission: suppression of nonradiative relaxation through structural or ligand-shell rigidification, modification of the electronic structure and radiative transitions, and enhanced intersystem crossing in phosphorescent systems. Particular attention is given to cases in which changes in quantum yield can be interpreted together with excited-state lifetimes and other spectroscopic data, allowing experimentally supported mechanisms to be distinguished from plausible but unverified explanations. We further evaluate the performance of biopolymer-protected polymetallic NCs in sensing and related applications and identify key limitations, including the scarcity of atomic structures and systematic excited-state measurements. This analysis provides a framework for connecting metal composition and molecular structure to luminescence and highlights strategies for the rational development of brighter, more stable, and biocompatible NCs. Full article

Recent advances in depth camera technology enable precise quantification of shape changes of the human torso during breathing and therefore predict respiratory volumes. The aim of this study was to investigate the potential of estimating tidal volumes during relaxed breathing from two depth cameras. Data were analysed from 21 healthy participants. For each participant, a set of 30 physical markers were placed across the torso and tracked using two depth cameras. Marker positions were mapped to 3D coordinates and used as inputs for a volume algorithm that estimated respiratory volumes. A breath-by-breath analysis was then conducted to compare estimated volumes with spirometry measurements. The camera-derived volumes were strongly correlated with spirometry (marginal R² = 0.941) and showed excellent agreement with a mean (SD) absolute difference of 78.0 (34.8) mL. Bland–Altman analysis showed a bias of −4.6 mL and 95% limits of agreement of −192.3 to 183 mL. The reduced 17-marker configuration also showed a strong correlation with spirometry (marginal R² = 0.918) but reduced agreement, with a mean (SD) absolute difference of 107.4 (58.2) mL and a Bland–Altman bias of −76.4 mL (95% limits of agreement: −298.1 to 145.3 mL). This is the first study to use a marker-based system to estimate respiratory volumes from two facing depth cameras. The use of markers allows for segmentation of the torso and therefore offers the potential to characterise breathing without the need for an expensive laboratory motion capture system. Full article

Low-altitude wireless networks (LAWNs) require reliable multi-user communication together with accurate range and velocity sensing. Communication and sensing share the same transmit power and spatial degrees of freedom (DoF), and therefore joint beamforming is required to coordinate multi-user spectral efficiency with delay-Doppler estimation accuracy. An adaptive multi-objective beamforming and power allocation framework is developed for a multiple-input multiple-output (MIMO) integrated sensing and communication (ISAC) base station. Communication performance is measured by the achievable multi-user sum spectral efficiency. Sensing performance is characterized by the Cramér–Rao lower bounds (CRLBs) for delay and Doppler frequency. A dimensionless system effectiveness integrated metric (SEIM) combines the three normalized performance components. The beamforming problem is lifted to transmit covariance matrices and treated via semidefinite relaxation (SDR) and alternating successive convex approximation (SCA) under power and per-user signal-to-interference-plus-noise ratio (SINR) constraints. An entropy-regularized weight subproblem provides a closed-form softmax update, and a damping step couples the weight update with the covariance iterations. Numerical results characterize the communication–sensing tradeoff with respect to the transmit power, array size, user loading, SINR requirements, and objective weights. Full article

Background/Objectives: Hydrogen sulfide (H₂S) is an important regulator of pulmonary vascular tone; however, the mechanisms underlying its biphasic contractile and relaxant effects, as well as the distinct contributions of endogenous and exogenous H₂S to nitric oxide (NO) signaling, remain incompletely understood. This study investigated the roles of endogenous and exogenous H₂S in regulating pulmonary vascular responses under physiological and oxidative stress conditions. Methods: Rat intrapulmonary arteries were studied using wire myography and simultaneous measurements of vascular force and intracellular Ca²⁺. Pharmacological inhibitors were used to examine the contribution of endogenous H₂S synthesis, NO synthase, soluble guanylate cyclase (sGC), K_ATP channels, and oxidative stress to vascular responses. Results: Sodium hydrogen sulfide (NaHS) produced biphasic concentration-dependent responses, with contraction at low concentrations followed by relaxation at higher concentrations. Simultaneous measurements of vascular force and intracellular Ca²⁺ showed that the initial contractile response to low concentrations of NaHS was not accompanied by a clear increase in intracellular Ca²⁺, whereas relaxation developed despite maintained or increasing intracellular Ca²⁺, indicating that NaHS-induced relaxation cannot be explained solely by reduced intracellular Ca²⁺ levels. Inhibition of endogenous H₂S synthesis reduced vascular responsiveness to the NO donor sodium nitroprusside, whereas relaxation induced by exogenous NaHS was largely preserved after inhibition of NO synthase or sGC, indicating distinct roles of endogenous and exogenous H₂S. Oxidative stress impaired acetylcholine- and riociguat-induced relaxation, while NaHS partially restored endothelial function. Conclusions: Endogenous and exogenous H₂S regulate pulmonary vascular tone through distinct mechanisms. Endogenous H₂S supports vascular responsiveness to NO, whereas exogenous H₂S induces relaxation largely independently of NO–sGC signaling. Furthermore, NaHS-induced relaxation occurs despite maintained intracellular Ca²⁺, suggesting an important contribution of Ca²⁺-independent mechanisms, and partially preserves endothelial function under oxidative stress. Full article

Organic-rich shale contains chemically heterogeneous mineral–organic interfaces that produce strong and spatially variable proton surface relaxation, complicating the identification of clay-bound water and the conversion of NMR relaxation time into pore size. Conventional interpretations commonly treat surface relaxivity as a constant, while the respective contributions of water-retaining surface chemistry, molecular restriction, and paramagnetic centers remain insufficiently separated. In this study, Wufeng–Longmaxi shale samples from the Yongchuan Block were investigated using mineralogical and pore structural characterization, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, cation exchange capacity, zeta potential, electron paramagnetic resonance, controlled hydration, one- and two-dimensional low-field time domain NMR, and molecular dynamics simulations. Under the present fluid and acquisition conditions, strongly surface-associated water was operationally identified mainly at T₂ < 1.6 ms and T₁ < 85 ms, while the effective transverse surface relaxivity ranged from 3.6 to 9.1 μm/s. Water retention was more closely associated with cation exchange capacity and surface –OH/O–C environments, whereas relaxation efficiency was controlled more directly by EPR-detectable paramagnetic centers and restricted molecular motion of interfacial water. Simulations of Na-smectite, chlorite, illite, and kerogen-covered illite revealed systematic differences in water density layering, adsorption strength, hydrogen bond persistence, molecular residence, translational diffusion, rotational reorientation, and proton–proton dipolar correlation. A chemistry-informed model combining the EPR-derived paramagnetic center density with a surface area-weighted molecular restriction index explained 86% of the measured relaxivity variation, with an adjusted R² of 0.83 and leave-one-out cross-validation RMSE and MAE values of 0.71 and 0.57 μm/s, respectively. At the core scale, the variable relaxivity interpretation reduced the mean absolute percentage error of characteristic pore diameter from 21.9% to 4.5% and the RMSE of the clay-bound water fraction from 3.4 to 0.4 percentage points relative to the fixed relaxivity method. Transfer to NMR logging further reduced lithology-dependent biases in pore size conversion and clay-bound water partitioning. These results define shale surface relaxivity as an emergent interfacial property arising from coupled magnetic and molecular controls and provide a mechanistic basis for NMR analysis of chemically heterogeneous shale materials. Full article

This study aims to verify and improve the Electrical Equivalent Circuit Model (EECM) for a regenerated VW e-Golf cell and to develop a verification and optimization framework that enhances simulation accuracy. The model is based on an identified set of EESB elements derived from enhanced measurements of the regenerated cell and is compared with the original cell. A global EESB model is implemented in the PLECS environment, comprising a charge/discharge block and a Voc versus SOC evaluation. Parameters are obtained from measurements of the regenerated VW e-Golf cell and augmented with SOC-dependent polynomial relationships for individual model components. The methodology was applied to identify EESB elements for the regenerated VW e-Golf cell and to produce an EESB model aligned with the identification results. Verification compares simulated and experimental curves in critical SOC regions (0–10%, around 30%, and during relaxation) and cross-validates regenerated versus original cells. Results show that SOC-based polynomial estimates extend the valid range of EESB elements to 0–10% SOC and improve agreement with measured trajectories. Optimization reduces the computational load and improves accuracy, particularly in critical SOC regions, supporting a robust verification framework for regenerated battery cells and guiding further research and implementation in BMS and simulation environments. Full article

Background/Objectives: Coffee aroma has been associated with psychological and physiological responses, although these responses have often been examined separately. This exploratory study used a multimodal approach to assess subjective mood, electroencephalographic (EEG) activity, heart rate (HR), and heart rate variability (HRV) following short-term coffee aroma exposure. Methods: Twenty healthy adults aged 20–29 years participated in a single-group, within-subject pre–post study and were exposed to coffee aroma for 5 min. Mood was assessed using the Profile of Mood States (POMS). Pre- and post-exposure measurements were compared using paired t-tests, with Holm adjustment for the six POMS subscales. Effect sizes, 95% confidence intervals (CIs), and exploratory cross-domain correlations were also examined. Results: Total Mood Disturbance decreased following exposure (mean change = −20.54, 95% CI: −30.65 to −10.43; Cohen’s dz = −0.95). After Holm adjustment, Fatigue, Tension–Anxiety, Confusion, and Depression–Dejection remained significantly reduced. The EEG-derived relaxation index increased (mean change = 0.0378, 95% CI: 0.0248–0.0508; dz = 1.36). No statistically significant changes were detected in HR (dz = 0.19) or HRV (dz = 0.13). Exploratory cross-domain analyses identified no significant associations among individual changes in subjective, cortical, and cardiovascular measures. Conclusions: Short-term coffee aroma exposure was followed by changes in subjective mood and an EEG-derived index, whereas no significant cardiovascular changes were detected. Multimodal assessment may provide complementary information regarding psychological and physiological changes following coffee aroma exposure, although controlled studies with larger samples are required. Full article

Perilla seed hulls are a promising but underutilized source of dietary fiber, yet little is known about how pretreatment-induced structural changes in soluble dietary fiber (SDF) derived from these hulls affect its functionality in cereal dough. This study compared SDF extracted from untreated, ultra-high-pressure (UHP)-pretreated, cellulase-pretreated, and sequentially UHP–cellulase-pretreated perilla seed hulls and evaluated their structural, physicochemical, and dough-modifying properties. The combined treatment increased the SDF content of the hull material from 3.71% to 8.63% and decreased insoluble dietary fiber from 55.74% to 50.37%. Relative to untreated SDF, the resulting UCPSDF had a lower apparent molecular weight (2442 vs. 2788 Da), a smaller mean particle size (2.76 vs. 3.62 μm), a lower glucose proportion, and higher arabinose and acidic monosaccharide proportions. FTIR, XRD, SEM, and thermal analyses indicated retention of the principal polysaccharide and cellulose-I signatures, accompanied by changes in structural characteristics and a looser, more porous morphology. UCPSDF also showed the highest water-holding and swelling capacities. At 6% supplementation, UCPSDF produced the strongest elastic response in wheat–corn composite dough, significantly increased springiness (0.59–0.72) and cohesiveness (0.64–0.76), increased the combined amide I-derived α-helix and β-sheet proportion of dough proteins from 53.93% to 66.82%, and reduced the T₂₃ relaxation time from 297.86 to 81.23 ms. These findings indicate that sequential UHP–cellulase pretreatment improves the measured SDF content and hydration functionality of perilla seed hull SDF and supports its use as a dough-structuring ingredient in wheat–corn composite foods. Full article

Extracting Cole–Cole relaxation parameters from broadband dielectric spectroscopy (BDS) of cross-linked polyethylene (XLPE) cable insulation is ill-conditioned when the dispersion peak lies outside the instrument frequency window. This paper proposes an identifiability-aware, physics-constrained machine-learning framework and quantifies the analytic bound on what is recoverable over [0.01, 10⁵] Hz. A Cramér–Rao lower bound (CRLB) analysis indicates that under the assumed model and noise conditions, ε_∞ and σ_dc are well identified (relative CRLB ≤ 0.05%), whereas ε_s and log τ remain weakly identifiable (|ρ| = 0.97). α is strongly correlated with log τ but retains a comparatively small marginal CRLB. A physics-based sim-to-real strategy generates 10,000 synthetic spectra; the domain gap against four reconstructed real spectra is measurable but not conclusively resolved at this sample size. A label-free physics-constrained spectral optimisation (PCO) step reduces the relative ε_s deviation at 140 °C from 37.8% to 8.8%, an improvement specific to the analysed spectrum that Monte Carlo analysis does not show to generalise across noise realisations; PCO does not improve on a 50-start Levenberg–Marquardt baseline at 180 °C, where residual deviations indicate estimator bias and/or model–data mismatch rather than an identifiability limit. A measurement design criterion shows that a 5% CRLB-based uncertainty target for log τ requires f_min ≤ 10⁻³ Hz. Because the assessment rests on a single digitally reconstructed dataset, the results constitute a methodological proof of concept rather than broad validation. Full article

Objectives: This systematic review aims to compare the forces and moments generated by thermoforming aligners and direct-printed aligners in guiding tooth movement in orthodontic patients, evaluating their impact on orthodontic outcomes. Methods: A systematic search was conducted in PubMed, Web of Science, and Scopus databases, covering studies on thermoforming and direct-printed aligners from inception to October 2024. Eligible studies included randomized controlled trials, quasi-experimental studies, and observational studies assessing forces and moments generated by these aligners on teeth. In vitro studies pertinent to the topic were also considered. Data extraction focused on study characteristics, aligner details, force and moment measurements, and clinical outcomes. Quality assessment utilized the ROBINS- I for Risk of Bias. The review has been registered on PROSPERO CRD42024620341. Results: A total of nine studies met the inclusion criteria. Findings indicate that thermoforming aligners, while effective in initial force application, exhibit significant force decay over time due to material stress relaxation. In contrast, direct-printed aligners maintain more consistent force levels, potentially resulting in more predictable and sustained tooth movement. Both aligner types vary in their ability to control force direction and magnitude, with direct-printed aligners showing advantages in customization and force retention. Conclusions: The biomechanical properties of thermoforming and direct-printed aligners offer distinct advantages and limitations. Direct-printed aligners may enhance clinical predictability and reduce treatment time through consistent force application, though further research is necessary to validate these benefits in clinical settings. This review underscores the importance of material selection and fabrication method in optimizing orthodontic outcomes. Full article

During the service life of karst tunnels, groundwater containing Ca²⁺ and CO₃²⁻ can migrate along the shotcrete–surrounding rock interface and induce calcite deposition, thereby changing the interfacial material composition and load transfer path. To clarify the effect of this process on interfacial bonding performance, this study used molecular dynamics simulations to construct CSH–SiO₂, SiO₂–calcite, CSH–calcite, and CSH–calcite–SiO₂ interface models. The interfacial density distribution, radial distribution function, number of hydrogen bonds, interaction energy, and normal tensile failure behavior were analyzed. The results show that all four models reached stable energy plateaus after relaxation, and clear atomic density overlap and short-range RDF peaks appeared in the interfacial regions. These descriptors indicate short-range contact and possible Ca–O electrostatic attraction, hydroxyl-related hydrogen bonding, and carbonate-associated interactions between calcite and both SiO₂ and CSH surfaces. Approximately 80 hydrogen bonds were formed at the SiO₂–calcite interface, approximately 32 at the CSH–calcite interface, and approximately 59 in total for the two hydrogen bond subtypes at the SiO₂–CSH interface, indicating that the hydroxyl state of different substrate surfaces controls the interfacial hydrogen bond network. Interaction energy analysis shows that the single CSH–calcite interface has the strongest interaction (−51,753.6 kcal/mol), approximately 1.90 times that of the SiO₂–CSH interface and 16.43 times that of the SiO₂–calcite interface. However, in the three-layer composite model, the interaction energy on the CSH–calcite side is only approximately 28.0% of that on the SiO₂–calcite side, suggesting that a continuous calcite interlayer introduces asymmetric interfacial constraints. Tensile simulations further show that the SiO₂–calcite model has the highest peak stress (approximately 3.23 GPa) and exhibits brittle failure, whereas failure in CSH-containing systems is more likely to transfer into the CSH layer or weakly connected regions. These results indicate that calcite deposition does not simply strengthen or weaken the interface. Instead, within the two idealized endpoint configurations tested here, its effect depends on deposition continuity, the surface chemistry of the two substrates, and the weak links within the serial interface. This study provides a nanoscale theoretical basis for evaluating relative trends in the long-term service performance of shotcrete–surrounding rock interfaces, and for guiding future multiscale validations of drainage and waterproofing measures in karst tunnels. Full article

Cutaneous wound healing is governed by dynamically interacting mechanical, redox, and bioelectrical signals that regulate cell migration, inflammation, angiogenesis, extracellular-matrix remodeling, and tissue regeneration. Hydrogels are increasingly engineered to modulate these cues; however, most systems are still described through independently measured properties such as stiffness, antioxidant activity, and conductivity, without demonstrating functional coupling among them. This review examines regenerative hydrogels from a cross-domain perspective, integrating the biological basis of mechanotransduction, redox signaling, endogenous bioelectricity, and their molecular convergence with the network-level mechanisms that control hydrogel behavior. Particular emphasis is placed on dynamic crosslinking, viscoelastic relaxation, hydration, redox-active chemistry, ionic and electronic transport, conductive and piezoelectric phases, and degradation-dependent evolution of material function. A conceptual hierarchy is proposed to distinguish property coexistence, structural integration, directional transduction, and adaptive feedback, together with experimental criteria and quantitative approaches for evaluating coupling. Current evidence indicates that mechanoelectrical coupling is the most mature, whereas mechanoredox and redox–electrical interactions remain less systematically quantified. Moving beyond descriptive multifunctionality toward controllable cross-domain transduction may enable hydrogels to function as adaptive soft interfaces capable of responding to the evolving physicochemical conditions of cutaneous regeneration. Full article