Catalytic methane combustion is an efficient way to remove methane from the exhaust of natural gas vehicles and mine ventilation streams, thereby mitigating its strong greenhouse impact and reducing the fire and explosion hazards. The most widely used catalysts for methane combustion are high-surface-area oxide supports with palladium-based nanoparticles. The promotion of Pd by noble and transition metals is one of the most effective strategies to enhance long-term stability of the catalytic nanoparticles. Here, in search of a synthetic approach to localize promoters in the vicinity of active sites, we systematically compare ternary Pd-Pt-Ni/Al2O3 catalysts with simultaneous addition of Pt and Ni promoters prepared via wet impregnation and colloidal synthesis. The efficient incorporation of promoters into the active phase, Pd1_ xPtxO nanoparticles, is achieved only for the catalyst prepared via colloidal synthesis. Contrary, in addition to Pd1_ xPtxO nanoparticles, wet impregnation results in the growth of Pt-enriched metal nanoparticles, whereas Ni is distributed uniformly over the Al2O3 support with the formation of NiAl2O4 phase. An innovative microcalorimetric approach was used to evaluate catalytic performance. Microcalorimetry showed that the Pd-Pt-Ni/Al2O3 catalyst obtained by wet impregnation has higher initial methane combustion activity, owing to larger, more easily reducible Pd1_ xPtxO nanoparticles. By contrast, the Pd-Pt-Ni/Al2O3 catalyst prepared using colloidal synthesis exhibits significantly greater long-term stability, which is caused by the promotion effect of Pt and Ni. These findings highlight the high potential of colloidal nanoparticles containing one or more promoters for the preparation of highly stable and highly active methane combustion catalysts.
Cardio-cerebrovascular vessel segmentation in heart and brain angiographic images provides a computational basis for quantitative vascular assessment and supports downstream analysis for diagnosis and intervention planning. In practice, this task is challenged by thin and tortuous branching geometry, non-uniform vessel visibility in TOF-MRA and CTA, and vessel-like artifacts that can lead to fragmented connectivity and false-positive responses. This paper presents HiLo, a spatial–spectral collaborative network with hybrid high–low frequency activation for heart–brain vessel segmentation. HiLo incorporates two core components: a HiLo block that disentangles and amplifies high- and low-frequency cues across spatial and spectral domains to jointly model boundary details and global context, and a tri-axial adaptive gating module that aggregates orthogonal context descriptors and applies a parameterized gate to enhance vessel-consistent activations while attenuating background interference. Experiments on two public benchmarks demonstrate improvements over representative spatial- and spectral-based baselines, achieving 80.02% DSC and 13.45 mm HD95 on the ImageCAS coronary artery dataset and 83.13% DSC and 11.74 mm HD95 on the CAS2023 cerebral artery dataset, with reduced HD95 indicating tighter boundary adherence along thin distal branches and complex bifurcations. Code: https://github.com/deepang-ai/HiLo.
This review systematizes current data on the structural organization, coordination chemistry, and functional roles of zinc-binding proteins and peptides. The mechanisms by which Zn2+ ions participate in homeostasis, enzymatic catalysis, signal transduction, and pathological processes are analyzed. A large dataset of zinc-containing protein structures deposited in the Protein Data Bank was examined. Tetrahedral coordination geometry predominates for zinc ions (over 67
This review summarizes current data on potential applications of the main classes of inorganic nanoparticles in ophthalmology, as well as their advantages and limitations, and systematizes data on the most studied inorganic nanoparticles, including gold and silver nanoparticles, metal oxides (e.g., iron oxide, zinc oxide), silica, and insoluble calcium salts. Particular attention is paid to their toxicity to eye tissues and the use as carriers for encapsulation and controlled release of various biologically active substances, such as antiglaucoma drugs, antibiotics, anti-inflammatory and antitumor agents. The review examines the results of in vivo experiments using nanoparticles, demonstrating their physiological effects, capacity to increase the bioavailability of drugs, and ability to prolong their therapeutic effect.
Resource efficiency has become a key criterion in evaluating methods of analytical chemistry. Microfluidic paper-based analytical devices generally meet this criterion. This article provides an overview of the main approaches to the development and application of microfluidic paper-based analytical devices as tools for resource-efficient chemical analysis. Fundamental principles of the design of such systems are discussed, including various methods of the formation of hydrophobic barriers on the paper surface and methods for recording the analytical signal (digital colorimetry, fluorescence and electrochemical detection). Potentials for combining these detection methods with paper microfluidic systems in the development of rapid, portable, and inexpensive screening assays are demonstrated.
