Search Results (9,645)

We develop a collection of nontrivial examples that illustrate and test recent stability results for linear control systems ($LCS$) on Lie groups. We treat the main structural classes: Abelian (${\mathbb{R}}^n$), nilpotent (Heisenberg), solvable non-nilpotent (rigid motions of the plane $SE\left(2\right)$), compact semisimple ($SO\left(3\right)$), noncompact semisimple ($SL(2,\mathbb{R})$ via Iwasawa decomposition) and mixed/Levi-type groups. The examples are designed to (i) show the sharpness of geometric boundedness criteria, (ii) exhibit typical failure modes (exponential escape, polynomial central drift, noncompact neutrals), and (iii) demonstrate how the canonical quotient and suitable outputs recover $BIBO$ stability. The executive framework ($ICS$ existence/uniqueness, canonical quotient $G/\Gamma$, $BIBO$ characterization, robustness and ISS-type bounds) is briefly recalled; the main part of the paper consists of detailed worked examples implementing the practical checklist for applying these theorems. Full article

Accurate identification of flooded layers by cased-hole logging is a critical challenge for fine-scale development and enhanced oil recovery in water-flooded oil fields at medium to high water-cut stages. Conventional methods based on single-series logging or two-dimensional crossplot techniques are inadequate for the fine-scale interpretation of complex low-permeability reservoirs. This paper proposes a novel flooded layer identification method through the deep integration of dynamic and static data. The proposed approach organically couples static open-hole logging data (porosity, resistivity, etc.) with dynamic cased-hole logging data (pulsed neutron macroscopic capture cross-section Σ and carbon–oxygen ratio, C/O) within a three-dimensional (3D) crossplot framework. A multidimensional feature parameter space is constructed, and a spatial distance-ratio model is established to quantitatively calculate the flooding index Fw for continuous evaluation of flood level (non-flooded, weakly flooded, moderately flooded, and strongly flooded). Field application in Well X of a low-permeability oil field successfully identified two ambiguous apparent water layers as weakly flooded layers, previously indistinguishable using traditional 2D methods, with interpretation results highly consistent with subsequent production tests. The identification accuracy reached over 90.7%, providing a scalable technical framework for cased-hole flooded layer evaluation in medium-to-low-permeability complex reservoirs. Full article

To improve clinical decision-making about Carbapenem-resistant Gram-negative bacteria (CR-GNB) infections and halt the spread of resistant microbes, quicker and less expensive diagnostic techniques are required. Thus, the purpose of this study was to thoroughly evaluate the diagnostic efficiency (sensitivity, specificity, and concordance) of direct-from-specimen multiplex lateral flow immunoassay (LFIA) across diverse raw clinical specimens and pathogen types from critically sick patients. A total of 300 non-duplicate samples were tested to detect CR-GNB. Five major Carbapenemase genes were detected directly from the specimen using carbapenem-resistant K.N.I.V.O. detection K-Set and from culture using culture-enhanced multiplex PCR. Turnaround time (TAT) of each method was calculated. The direct LFIA revealed 100% specificity for NDM, KPC, and IMP enzymes in all tested clinical matrices (blood, urine, and respiratory samples). The study demonstrated 100% sensitivity and specificity with perfect categorical agreement (κ = 1.000) for the blaKPC in the Klebsiella pneumoniae and for blaOXA-48 and blaIMP in the Acinetobacter baumannii; however, sensitivity of blaVIM was significantly diminished across all isolates and samples. TAT decreased significantly (p < 0.001) from 30 to 70 h to about 50 min. The tested direct LFIA facilitates the prompt enhancement of lifesaving tailored antibiotic treatment for severe illnesses. Full article

Background: Near-infrared spectroscopy (NIRS)-based wearable devices offer non-invasive, continuous monitoring of muscle oxygenation, providing direct microvascular and metabolic information that complements indirect indices of intensity such as heart rate and accelerometry. Their clinical applicability in chronic non-communicable diseases (NCDs) remains under active development. Methods: A structured narrative review was conducted in PubMed, Scopus, Web of Science, and IEEE Xplore (January 2010–January 2026) using pre-specified search strings combining NIRS, muscle oxygenation, SmO₂, StO₂, wearable, exercise intensity, ventilatory/lactate threshold, and individual chronic disease terms. Eligible studies addressed technical validation of wearable NIRS, NIRS-derived exercise intensity estimation, clinical applications in NCDs, or rehabilitation implementation. Evidence was synthesized thematically; quality of validation studies was appraised against AMSTAR-2-informed, COSMIN-informed, or Cochrane RoB-2 criteria. Results: Wearable continuous-wave NIRS shows acceptable concurrent validity with frequency-domain laboratory systems (r = 0.79; range 0.69–0.88; ±8% SmO₂ agreement in 95% of measurements) and good test–retest reliability for moderate-to-severe domains (ICC 0.72–0.91). NIRS-derived breakpoints align more reliably with the second ventilatory/lactate threshold (ICC = 0.80) than with the first (ICC = 0.53), constraining its use for prescribing lower-intensity domains. In chronic obstructive pulmonary disease, peripheral arterial disease, chronic respiratory failure and selected cardiovascular conditions, wearable NIRS detects disease-specific patterns of muscle deoxygenation and post-exercise reoxygenation that track responses to rehabilitation. Conclusions: Current evidence supports wearable NIRS as a complementary, intensity-aware monitoring tool—particularly for delineating the heavy/severe-intensity boundary and detecting peripheral metabolic limitations—rather than as a stand-alone replacement for ventilatory or lactate thresholds. Because much of the evidence derives from small, single-sex or athlete-only cohorts, these findings should be regarded as a promising basis requiring further validation in broader NCD populations. Implementation in NCDs requires standardized placement and calibration protocols, sex- and body composition-stratified reference values, motion-artifact mitigation, and adequately powered longitudinal trials in clinical populations. Full article

The growing need for secure image transmission across public networks requires robust encryption algorithms. Traditional chaos-based image ciphers typically have a small key space, weak avalanche behavior, or are susceptible to differential cryptanalysis. To overcome such inadequacies, this paper suggests a new adaptive image cryptosystem that combines a fractional-order memristive chaotic engine and a non-linear hybrid encryption kernel. The system uses piano-inspired feedback; the keystream generator dynamically adapts to the previously encrypted pixel, enabling powerful Cipher Block Chaining (CBC)-style chaining and content-dependent diffusion. A four-dimensional memristive system is solved by the use of fractional-order calculus, which gives an ultra-large key space (>10⁸⁰) and very high sensitivity to initial conditions—confirmed by a positive largest Lyapunov exponent (1.7199). The encryption kernel maps the traditional Exclusive OR (XOR) with the reversible two-step operation: the modular addition of the plaintext with the first keystream byte and the XOR with the second keystream one, both of which increase non-linearity and confusion. Large-scale experiments with six standard 256 × 256 colour images indicate almost ideal entropy (7.9994), Number of Pixel Change Rate (NPCR) which is 99.62, Unified Average Changing Intensity (UACI) which is 33.43, correlation coefficients are near to zero, very low Gray-Level Co-occurrence Matrix (GLCM) homogeneity (≈0.017) and high contrast (≈4843) and low energy (≈0.006 The ciphertext passes seven National Institute of Standards and Technology (NIST) SP-800-22 statistical tests, is extremely sensitive to keys (a perturbation of 1 × 10⁻¹⁴ alters >99.6% of ciphertext) and resists chosen-plaintext and known-plaintext attacks. Decryption has linear time complexity O(N), and average encryption and decryption times are 3.40 s and 2.75 s for 256 × 256 images. The proposed cryptosystem provides an attractive security–performance trade-off that can be used in high-security systems like medical image protection, privacy-preserving multimedia transmission, and secure cloud storage. Full article

Beamspace adaptive matrix spatial filters have been extensively studied for their superior nulling performance and mathematical elegance. However, a major drawback of current spatial filters is the high computational cost—often reaching $\mathcal{O}\left(M^{4.5}\right)$—due to their formulation as second-order cone programming (SOCP) problems that rely on iterative interior-point methods. This paper proposes a robust and efficient matrix filtering framework with adaptive nulling capabilities to suppress interference. The proposed method is formulated as a convex optimization problem that admits a non-iterative, closed-form solution, thereby reducing the complexity to $\mathcal{O}\left(M^3\right)$. Consequently, it can be efficiently implemented on resource-constrained embedded platforms. Furthermore, the algorithm incorporates an explicit passband flatness constraint, which significantly improves compatibility with downstream Direction-of-Arrival (DOA) estimation modules. To achieve even greater efficiency, we introduce a novel dual sequential rank-1 update strategy, further lowering the overall computational complexity to $\mathcal{O}\left(M^2\right)$. Full article

The zinc–copper (Zn-Cu) voltaic battery is the first battery made in human history, but the Cu²⁺ dissolution issue leads to the reaction’s irreversibility. To tackle this challenge, solid-state electrolytes, ion exchange membranes, and functional electrolytes have been proposed to mitigate the Cu²⁺ dissolution; however, these approaches incur limitations like cell complexity, high cost, and anode corrosion. Herein, we develop a simple yet effective strategy to mitigate Cu²⁺ dissolution and build a rechargeable voltaic battery from cost-effective materials, including commercially available micro-copper powders and non-corrosive zinc acetate electrolyte. Importantly, the near-neutral Zn(Ac)₂ electrolyte provides some amounts of hydroxide and facilitates the Cu₂O/Cu solid–solid conversion reaction, thereby inhibiting the generation of soluble Cu²⁺ ions. As a result, the Zn-Cu battery exhibits a reversible capacity of ~130 mAh g⁻¹, a feasible voltage of 0.87 V, and a stable cycling life over 100 cycles. Our work provides a feasible strategy for developing rechargeable and cost-effective Zn-Cu batteries. Full article

Hierarchical ZnO–SiO₂/carbon composites (C-Zn1, C-Zn2, C-Zn3) were synthesised via the carbonisation of resorcinol–formaldehyde gels in the presence of ZnO-modified fumed silica, and characterised by N₂ adsorption–desorption, FTIR, XRD, SEM, and zeta potential analysis. The composites exhibited hierarchical micro–mesoporous structures with BET surface areas of 467–499 m² g⁻¹; the non-microporous volume fraction increased from 0.09 (reference carbon RFC, 545 m² g⁻¹) to 0.54–0.63 upon ZnO–SiO₂ incorporation. Adsorption of methylene blue (MB), crystal violet (CV), and rhodamine 6G (R6G) followed the Marczewski–Jaroniec isotherm model. Maximum adsorption capacities for the best-performing composite (C-Zn1) reached 1.22 mmol g⁻¹ for MB, 1.04 mmol g⁻¹ for CV, and 0.63 mmol g⁻¹ for R6G, compared to 1.32, 1.17, and 0.67 mmol g⁻¹ for unmodified RFC. Kinetic analysis revealed up to 3.5-fold faster adsorption rates for C-Zn1 relative to RFC (for CV and R6G), attributed to enhanced diffusion through mesoporous channels while preserving the micropore-driven capacity. Agar well-diffusion assays against four bacterial strains showed no inhibition zones for any composite, indicating that no biologically active concentration of zinc species was released under the assay conditions. The proposed approach yields composites with enhanced adsorption kinetics, preserved capacity, and confirmed non-leaching character, positioning them as effective candidates for water purification. Full article

Fruit and vegetable processing by-products, such as peels and pomace, are rich in antioxidant polyphenols and represent promising sources of functional ingredients, but how their galloyl-based polyphenols interact with starch remains insufficiently understood. In this study, corilagin with three non-free galloyl moieties and 1,2,3,4,6-O-pentagalloyl glucose with five free galloyl moieties were used as model polyphenols to clarify how galloyl moiety number and accessibility modulate their complexation with high-amylose maize starch (HAMS). Size-exclusion chromatography showed that both polyphenols preferentially complexed with amylose, while FTIR confirmed that complex formation occurred mainly through non-covalent interactions. The two polyphenols induced distinct changes in HAMS structure. Corilagin disrupted short-range order and produced no detectable crystalline structure, whereas 1,2,3,4,6-O-pentagalloyl glucose enhanced molecular order and induced V-type crystallization. Isothermal titration calorimetry revealed more binding sites but weaker affinity for corilagin, with thermodynamic signatures indicating hydrogen bonding and van der Waals interactions. By contrast, 1,2,3,4,6-O-pentagalloyl glucose showed stronger affinity and hydrophobic interaction-dominated binding. Molecular dynamics simulations further confirmed that 1,2,3,4,6-O-pentagalloyl glucose formed a more stable association with the amylose helix than corilagin. These results indicate that galloyl moiety characteristics markedly influence starch–polyphenol interaction mechanisms, providing guidance for the utilization of polyphenol-rich agro-processing by-products in functional starch-based foods. Full article

For the first time, twenty spun polychrome glass figurines (considered as tangible cultural heritage objects) stylistically assigned to workshops of the city of Nevers from the 17th to 19th centuries have been analyzed at the Musée de la Faïence et des Beaux-Arts of Nevers using non-invasive XRF and Raman spectroscopy. The results are compared with those previously obtained for figurines assigned to the Perrot’s Orléans workshop. A wide variety of glass compositions is observed, ranging from lead-free to lead-rich compositions, which are attributed to the preparation technique that involves mixing glass stems of different origins during the creation of the figurine. White opacification is achieved with Ca₂Sb₂O₇. The cobalt source is consistently arsenic-rich, but its composition becomes more complex during the 18th century, indicating the use of different cobalt sources. A variety of lead-tin and Naples yellow pigments are identified. Metal nanoparticles are used for pink, ruby, and carnation colors. The detection of associated arsenic and/or tin supports the identification of the use of gold nanoparticles. Cassiterite and arsenates of lead/calcium/potassium are also detected in a few figurines, probably from a different workshop. This latter opacifier, being more frequent in previously studied artifacts assigned to Orléans, suggests that the assignment to Nevers could be questioned. Aventurine glass is present in two objects. Full article

The Heilongtai–Maogudui (HM) mafic intrusions are exposed in the southern margin of the North China Craton (SNCC), which are contemporaneous with a variety of strategic metal/non-metal minerals (niobium, uranium, and high-purity quartz) and magmatic hydrothermal REE deposits. New geochronology and geochemistry of these intrusions are examined and interpreted to decipher their petrogenesis and tectonic settings. Zircon LA–ICP–MS data formed a concordant cluster, yielding a mean ²⁰⁶Pb/²³⁸U age of 397.5 ± 3.5 Ma, which is interpreted as an Early Devonian crystallization age. The HM mafic intrusions have similar whole-rock geochemical compositions, containing 48.94–51.51 wt% SiO₂, 1.26–1.61 wt% TiO₂, 5.96–7.13 wt% MgO, and 11.00–12.48 wt% FeO_t. The total alkali contents range from 1.61 wt% to 3.53 wt%, with Mg^# values of 47.23–52.30. The petrographic and geochemical results suggest the fractional crystallization of mainly olivine, clinopyroxene, and minor Fe–Ti oxide in the mafic intrusions. Being of tholeiitic composition, these mafic rocks display relatively flat rare earth element (REE) and trace element patterns, which are similar to those of the normal mid-ocean ridge basalt (N–MORB) and the enriched mid-ocean ridge basalt (E–MORB). The HM mafic intrusions are proposed to originate in the continental extensional environment through 5–10% partial melting of the depleted spinel asthenosphere mantle source. This is attributed to the gravitational delamination of the lithospheric mantle and the upwelling of the hot asthenosphere, marking the end of the Paleozoic Proto–Tethyan orogenic cycle. The Paleozoic strategic mineral deposits are proposed to have formed under this specific tectonic regime. Full article

Trimethylamine (TMA), a characteristic volatile biogenic amine generated during aquatic product spoilage, has a concentration that quantitatively reflects product freshness. Therefore, developing a rapid and accurate method for TMA detection is important for food safety control. Herein, this study synthesized high-performance hollow SnO₂ nanospheres via a hydrothermal method, aiming to develop a rapid, non-destructive gas sensor for TMA detection and evaluate its feasibility for assessing aquatic product freshness. The material exhibited a high response (Ra/Rg = 10.5@100 ppm), rapid response-recovery kinetics (10 s/20 s), and good selectivity. These properties were attributed to the high specific surface area, efficient gas diffusion channels, and abundant active sites provided by the hollow structure, which enhances the sensor’s response rate. Ultraviolet–visible diffuse reflectance spectroscopy further showed that the hollow structure narrows the bandgap of SnO₂, which may facilitate electron transfer and contribute to the enhanced response to TMA. In practical applications, a MEMS sensor based on SnO₂ hollow nanospheres successfully detected TMA concentration changes from sea bass during 0–8 days of refrigerated storage, demonstrating its potential reliability for rapid freshness assessment of aquatic products and providing a technological route for quality evaluation. Full article

Direct ammonia fuel cells (DAFCs) offer a promising pathway for carbon-free energy conversion but their practical performance is limited by sluggish cathode kinetics. In this work, non-precious FeCoN catalysts offer a cost-effective solution, yet carbon support optimization is crucial for activity and stability. FeCoN/XC-72R, FeCoN/CNT, and FeCoN/CNH cathode catalysts were synthesized by annealing at 550–750 °C. Their structure and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical behavior was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in alkaline medium containing KOH and NH₄OH. FeCoN/XC-72R exhibited the lowest resistance of 27 Ω and superior activity. In single cell tests using a 40 wt% PtIr/C anode catalyst at 2 mg cm⁻², the FeCoN/XC-72R catalyst achieved the highest power density of 71 mW/cm² under optimized conditions of 0.1M NH₄OH + 3M KOH, 100 °C, and O₂ feed. Among the carbon supports, carbon black (XC-72R) proved the most effective support for FeCoN catalysts in low concentration DAFCs, outperforming carbon nanotubes (CNTs) and carbon nanohorns (CNHs). These findings highlight the importance of carbon support selection in the design of efficient cathodes for next generation low concentration direct ammonia fuel cells. Full article

Ginkgo biloba seeds are a rich source of flavonoids and the unique terpene lactones—ginkgolides and bilobalide, known for their neuroprotective and cognitive-improving effects. However, unlike the widely used leaves, the seeds contain substantial levels of ginkgolic acid and ginkgotoxin (4′-O-methylpyridoxine), an antivitamin B₆ compound. At high concentrations, ginkgotoxin exhibits neurotoxicity, potentially inducing seizures, respiratory distress, and loss of consciousness, thus limiting the safe application of Ginkgo seed-derived products. This study aimed to develop a simple yet effective extraction protocol that reduces ginkgotoxin levels in Ginkgo biloba seed extracts while preserving their beneficial phytochemicals. A multistep liquid–liquid extraction approach employing sequential polar and non-polar solvents was implemented. Following each extraction stage, fractions were analyzed using ultra-high-performance liquid chromatography coupled with mass spectrometry (UHPLC–MS). The concentrations of flavonoids, ginkgolides, bilobalide, ginkgolic acid, and ginkgotoxin were quantified to evaluate detoxification efficiency and phytochemical retention. Compared with conventional single-step extraction using 70% methanol, this multistep protocol markedly reduced ginkgotoxin and ginkgolic acid to near-undetectable levels, while preserving detectable concentrations of major flavonoids and terpene trilactones. The findings demonstrate that multistep extraction represents a promising and practical strategy for minimizing ginkgotoxin in Ginkgo biloba seed extracts without compromising their beneficial phytochemical composition. This approach provides a sound basis for developing safer, functionally active Ginkgo-based products. Full article

Layered Li-rich manganese-based Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ (LNCMO) is regarded as a promising high-capacity cathode material. However, its commercial application is severely hindered by rapid capacity fading, serious voltage decay and poor cycling stability. Herein, a facile non-sintering electrostatic adsorption strategy employing PDDA is proposed to fabricate a uniform and dense graphene oxide (GO) coating on LNCMO particles. Structural and morphological characterizations confirm the successful decoration of GO on the surface of LNCMO. The optimized 0.5@LNCMO sample delivers a discharge capacity of 330 mAh g⁻¹ at 0.1C, and maintains a capacity retention of 86.5% after 200 cycles at 1C and 83.3% after 400 cycles at 5C, showing much better electrochemical performance than pristine LNCMO. This study proves that the proposed strategy is an effective modification method for constructing high-performance Li-rich cathode materials. Full article