Search Results (1,339)

Improving the efficiency of photocatalysts for hydrogen production while minimizing the amount of noble metals used is a pressing issue in modern green energy. This study examines the effect of ultra-small Pt additives on increasing the efficiency of the CuO_x-dark TiO₂ photocatalyst used in the hydrogen evolution reaction (HER). Initially, Pt was photoreduced from the hydroxonitrate complex (Me₄N)₂[Pt₂(OH)₂(NO₃)₈] onto the surface of nanodispersed CuO_x powder obtained by pulsed laser ablation. Then, the obtained Pt-CuO_x particles were dispersed on the surface of highly defective dark TiO₂, so that the mass content of Pt in the samples varied in the range from 1.25 × 10⁻⁵ to 10⁻⁴. The prepared samples were examined using HRTEM, XRD, XPS, and UV-Vis DRS methods. It has been established that in the Pt-CuO_x particles, platinum is mainly present in the form of single atoms (SAs), both as Pt²⁺ (predominantly) and Pt⁴⁺ species, which should facilitate electron transfer and contribute to the manifestation of the strong metal–support interaction (SMSI) effect between SA Ptⁿ⁺ and CuO_x. In turn, in the Pt-CuO_x-dark TiO₂ samples, surface defects (O_v) and surface OH groups on dark TiO₂ particles act as “anchors”, promoting the spontaneous dispersion of CuO_x in the form of sub-nanometer clusters with the reduction of Cu²⁺ to Cu¹⁺ when localized near such O_v defects. During photocatalytic HER in aqueous glycerol solutions, irradiation was found to initiate a large number of catalytically active Pt⁰-CuO_x-O_v-dark TiO₂ centers, where the SMSI effect causes electron transfer from titania to SA Pt, thus promoting better separation of photogenerated charges. As a result, ultra-small additives of Pt led to up to a 1.34-fold increase in the amount of released hydrogen, while the maximum apparent quantum yield (AQY) reached 65%. Full article

Graphitic carbon nitride is recognized as a very promising support structure to anchor single atoms and small, sub-nanometric metal clusters, with vast applications in catalysis. In the current manuscript, we aim to study the geometry and electronic structures of the small, sub-nanometric monometallic (copper or nickel) and bimetallic (copper–nickel) clusters anchored to the graphitic carbon nitride. Our Density Functional Theory (DFT) study reveals that Cu and Ni, when in the form of isolated single atoms, lie in the plane of the support. Once the atoms agglomerate and form small clusters, they tend to bind above the carbon nitride (C₃N₄) plane. The nickel atoms form shorter bonds with the support than the copper atoms do, which is reflected by the binding energies. Atoms directly bound to the support become oxidized, forming electrophilic sites at the surface. The computed negative metal–support binding energies mean that the investigated Cu/Ni-C₃N₄ composites are stable, and the metal species will not easily leach from the support. Full article

Alkaline pectate lyases hold significant promise for various industrial applications, including the degumming processes in papermaking and textiles. In this study, a novel pectinase, PelA, derived from a strain of Paenibacillus borealis, was characterized both at the molecular level and through enzymatic analysis. This enzyme represents a distinct cluster diverging from the well-characterized Bacillus pectinases and exhibits molecular activity under alkaline conditions, with an optimal pH of 9.5. It can be classified as an endo-(1,4)-pectate lyase, capable of cleaving the α-1,4 glycosidic bonds of polygalacturonic acid via a trans-elimination mechanism. Notably, the addition of the metal ion Ca²⁺ did not enhance enzyme activity. To achieve high-level secretory expression and improve its economic viability for bioapplications, the gene copy number of pelA in the host genome was increased by constructing tandem pelA gene expression cassettes. Following optimization of cultivation conditions and monitoring of cell growth, the recombinant strain harboring the multi-copy pelA gene attained an expression level of 7520 U/mL in a bioreactor. This study successfully achieved high-level secretory expression of an alkaline pectinase, thereby enhancing its potential for industrial bioapplications and providing a reference for future research on the heterologous expression of target genes. Full article

Esophageal squamous cell carcinoma (ESCC) accounts for the majority of esophageal cancers worldwide, with a poor prognosis and increasing resistance to conventional treatments. Faced with these limitations, nanoparticles (NPs) are attracting growing interest as innovative therapeutic agents capable of improving specificity and efficacy and reducing systemic toxicity. This study critically examines the pharmacological effects, mechanisms of action, and toxicity profiles of different metallic or organic nanoparticles tested on ESCC cell lines. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines were followed by a meticulous literature search of Google Scholar, Web of Science, PubMed/Medline, and Scopus databases to achieve this goal. The results show that the anti-tumor properties vary according to the type of nanoparticle (copper(II) oxide (CuO), silver (Ag), gold (Au), nickel(II) oxide (NiO), nano-curcumin, etc.), the synthesis method (chemical vs. green), and the biological activity assessment method (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Bromodeoxyuridine (BrdU), Cell Counting Kit-8 (CCK8) assays, etc.). NPs derived from green synthesis, such as those based on Moringa oleifera, Photinia glabra, or pomegranate bark, exhibit moderate cytotoxic activity (50% inhibitory concentration (IC₅₀) between 92 and 500 µg/mL) but show good tolerance on normal cells. In contrast, chemically synthesized NPs, such as Cu(II) complexes with 1,3,5-benzenetricarboxylic acid (H₃btc) or 1,2,4-triazole (Htrz), show lower IC₅₀ (34–86 µM), indicating more marked cytotoxicity towards cancer cells, although data on their toxicity are sometimes lacking. In addition, multifunctional nanoparticles, such as gold-based nano-conjugates targeting Cluster of Differentiation 271 (CD271) or systems combined with doxorubicin, show remarkable activity with IC₅₀ below 3 µM and enhanced tumor selectivity, positioning them among the most promising candidates for future clinical application against ESCC. The most frequently observed mechanisms of action include induction of apoptosis (↑caspases, ↑p53, ↓Bcl-2), oxidative stress, and inhibition of proliferation. In conclusion, this work identifies several promising nanoparticles (silver nanoparticles derived from Photinia glabra (PG), gold-based nano-immunoconjugates targeting CD271, and silver–doxorubicin complexes) for future pharmaceutical exploitation against ESCC. However, major limitations remain, such as the lack of methodological standardization, insufficient in vivo and clinical studies, and poor industrial transposability. Future prospects include the development of multifunctional nanocomposites, the integration of biomarkers for personalized targeting, and long-term toxicological assessment. Full article

Supported metal catalysts are extensively applied in the heterogeneous catalysis field. However, metal species are prone to migration and aggregation during catalytic reactions due to their high surface energy, which leads to deactivation. In recent years, the use of porous materials, particularly zeolites, to anchor metal species has gained significant attention. By confining metal single atoms, subnanometer metal clusters, and nanoparticles within the pores or nanocavities of these materials, the dispersion and stability of the metal species can be greatly enhanced, thereby improving the catalytic performance. This review systematically discussed the synthesis principles and diverse methodologies to fabricate zeolite-encapsulated metal catalysts. It further outlined their catalytic applications across various catalysis fields, emphasizing enhanced stability and selectivity enabled by confinement effects. Finally, the review provided critical perspectives on future developments, addressing challenges in precise structural control and scalability for industrial implementation. Full article

Zeolites are promising materials for volatile organic compound (VOC) adsorption and catalytic oxidation, where tuning their structure via defect engineering can enhance adsorption capacity and active metal dispersion. In this study, a concentration-sensitive chelation strategy using diethylenetriaminepentaacetic acid (DTPA) was developed to achieve moderate dealumination for Beta and Y zeolites. For Y zeolite, 0.1 M DTPA treatment increased the toluene adsorption capacity from 59 to 110 mg/g. After platinum (Pt) loading, both DTPA-modified Beta- and Y-based catalysts showed improved toluene oxidation efficiency compared to their unmodified counterparts. Remarkably, the Y-DTPA-0.01-Pt catalyst achieved 90% toluene conversion at 150 °C with CO₂ selectivity above 90%. DRIFTS and H₂-TPR results confirmed that moderate dealumination by DTPA generated silanol defects in zeolite Y that strongly anchored Pt²⁺ in a highly dispersed form and suppressed PtO formation. Severe dealumination using 0.1 M DTPA created larger defects that favored the aggregation of Pt⁰ clusters whilst causing significant loss in the micropores, thus reducing the Pt loading content and catalytic activity. This work demonstrates a simple and effective approach to optimize zeolite-based catalysts by controlling defect formation through controllable chelation, offering new insights into VOC abatement via tailored support design. Full article

Employing some simple physics-inspired density-based information-theoretic approach (ITA) quantities to predict the electron correlation energies remains an open challenge. In this work, we expand the scope of the LR(ITA) (LR means linear regression) protocol to more complex systems, including (i) 24 octane isomers; (ii) polymeric structures, polyyne, polyene, all-trans-polymethineimine, and acene; (iii) molecular clusters, such as metallic Be_n and Mg_n, covalent S_n, hydrogen-bonded protonated water clusters H⁺(H₂O)_n, and dispersion-bound carbon dioxide (CO₂)_n, and benzene (C₆H₆)_n clusters. With LR(ITA), one can simply predict the post-Hartree-Fock (such as MP2 and coupled cluster) electron correlation energies at the cost of Hartree-Fock calculations, even with chemical accuracy. For large molecular clusters, we employ the linear-scaling generalized energy-based fragmentation (GEBF) method to gauge the accuracy of LR(ITA). Employing benzene clusters as an illustration, the LR(ITA) method shows similar accuracy to that of GEBF. Overall, we have verified that ITA quantities can be used to predict the post-Hartree-Fock electron correlation energies of various complex systems. Full article

Supports used in heterogeneous metallic catalysts serve as a structural skeleton across which metallic nanoparticles are dispersed, but specific properties of the supports may also determine the behavior of these nanoparticles in catalytic processes. For example, it is known that among various properties of crystalline alkaline earth metal oxides serving as supports, the ability of their surface sites to donate electrons, that is their basicity, has an influence on the characteristics of the adsorbed metal. In the present work, the influence of MeO (Me = Mg, Ca, and Sr) basicity on the adsorption of Pb on the (100) surface of MeO crystals is studied by means of a dispersion-corrected density functional theory (DFT-D) computational method. The DFT-D calculations have characterized essential structural parameters, energetics, and the distribution of the electron charge for the Pb atoms and Pb dimers adsorbed at the regular O²⁻ and defective F_s centers of MeO(100). It has been observed that an increase in the basicity of MeO(100) in the sequence MgO < CaO < SrO results in a more energetically favorable effect of Pb adsorption, a stronger interaction between Pb and the surface, and a greater amount of electron charge acquired by the adsorbed Pb atoms and dimers. These findings contribute to a better understanding of how support basicity may modulate certain characteristics of MeO-supported metallic catalysts containing Pb as an additive. From a computational viewpoint, this work shows that the inclusion of spin–orbit relativistic correction in the DFT-D calculations leads to a significant reduction in the strength of the interaction between Pb and MeO(100), but it does not change the aforementioned trend in the strength of this interaction as a function of support basicity. Full article

Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to isolate and characterize multidrug-resistant K. pneumoniae strains from healthy rabbits raised for human consumption, with a focus on antimicrobial resistance genes, plasmid content, and associated mobile genetic elements. A total of 295 fecal samples were collected from rabbits across 20 commercial farms in northern Portugal. Isolates were confirmed using MALDI-TOF MS, tested for hypermucoviscosity, and subjected to antimicrobial susceptibility testing (EUCAST). Whole-genome sequencing (WGS) was performed to determine sequence types (STs), resistance genes, plasmids, and resistance determinants for metals and biocides. Six K. pneumoniae isolates were recovered, showing extensive antimicrobial resistance profiles, including ESBL genes such as bla_CTX-M-15, bla_SHV-28, and bla_TEM-1. The most frequent ST was ST307. Multiple genes resistant to heavy metals were identified. Plasmid analysis revealed the presence of IncFII, IncN, and ColRNAI types. Network analysis showed clusters of genetically related isolates and highlighted shared resistance mechanisms. The presence of multidrug-resistant K. pneumoniae in healthy rabbits destined for human consumption underscores the zoonotic potential of this species and the need for surveillance in the animal–food–human interface. These findings contribute to a better understanding of resistance ecology in the context of One Health. Full article

The article is devoted to the theoretical development of the mechanisms of molecular refrigeration, the area combining molecular magnetism and material science with promise for low-temperature physics and quantum computing, where conventional principles of refrigeration become inefficient. Given this general trend, we propose the concept of the magnetothermal effect in magnetically anisotropic complexes of 3d metal ions, caused by fast magnetic field quenching. Within this concept, the most topical case of an axially magnetically anisotropic system isolated from the environment by adiabatic envelope is analyzed. We evaluate the temperature change as a function of the initial temperature and magnetic field and also its dependence on the sign and the magnitude of the axial zero-field splitting parameter and the Debye temperature. Correlations are revealed between the sign of the magnetic anisotropy (dictated by the sign of the axial zero field splitting parameter) and the sign of the thermal effect (heating versus cooling) caused by field quenching. The temperature change is shown to be negative (cooling) in the case of complexes exhibiting easy-axis-type magnetic anisotropy, while for the case of easy-plane-type anisotropy, it proves to be positive (heating). The thermal effects are shown to have an efficient control by varying the initially applied field. These findings allow us to propose complexes exhibiting easy-axis-type magnetic anisotropy as candidates for achieving a low-temperature refrigeration effect caused by fast field quenching and also to employ the established magnetothermal correlations to the analysis of magnetic anisotropy. Full article

Groundwater quality in arid and semi-arid regions of Morocco is under increasing pressure due to both anthropogenic influences and climatic variability. This study investigates the physicochemical and heavy metal characteristics of groundwater across four Moroccan regions (Tangier-Tetouan-Al Hoceima, Oriental, Souss-Massa, and Marrakech-Safi) known for being argan tree habitats. Thirteen groundwater samples were analyzed for twenty-five parameters, including major ions, nutrients, and trace metals. Elevated levels of ammonium, turbidity, electrical conductivity, and dissolved oxygen were observed in multiple samples, surpassing Moroccan water quality standards and indicating significant quality deterioration. Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) detected arsenic concentrations exceeding permissible limits in sample AW11 alongside widespread lead contamination in most samples except AW5 and AW9. Spatial patterns of contamination were characterized using Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), K-means clustering, and GIS-based Inverse Distance Weighted (IDW) interpolation. These multivariate approaches revealed marked spatial heterogeneity and highlighted the dual influence of geogenic processes and anthropogenic activities on groundwater quality. To assess consumption suitability, a Water Quality Index (WQI) and Human Health Risk Assessment were applied. As a result, 31% of samples were rated “Fair” and 69% as “Good”, but with notable non-carcinogenic risks, particularly to children, attributable to nitrate, lead, and arsenic. The findings underscore the urgent need for systematic groundwater monitoring and management strategies to safeguard water resources in Morocco’s vulnerable dryland ecosystems, particularly in regions where groundwater sustains vital socio-ecological species such as argan forests. Full article

Staphylococcus shinii (S. shinii) is a coagulase-negative species primarily associated with the degradation of organic matter, contributing to nutrient cycling in natural environments. This species has been mainly studied in clinical and terrestrial contexts, with no previous reports of its presence in marine environments. In this study, we report the first isolation of S. shinii from a marine habitat. The strain SC-M1C was isolated from the Red Sea sponge Negombata magnifica. Whole-genome sequencing confirmed its taxonomic identity as S. shinii. The genome uncovers potential adaptive characteristics that facilitate survival in marine ecosystems, comprising genes associated with osmoregulation, nutrient acquisition, stress response, and resistance to heavy metals. Moreover, multiple genomic islands and plasmids were identified, suggesting a potential role in horizontal gene transfer and environmental adaptability. The presence of biosynthetic gene clusters linked to non-ribosomal peptides, siderophores, and terpene production indicates potential for biochemical versatility beyond traditional metabolic expectations. This study presents the first genomic insights into S. shinii in a marine context, highlighting its ecological significance and adaptive mechanisms in a high-salinity environment. These findings expand our understanding of staphylococcal ecology beyond terrestrial and clinical origins and provide a foundation for exploring the role of S. shinii in marine microbial interactions and environmental resilience. Full article

Background: Thallium is a metal that is ubiquitous in our natural environment. Despite its potential for high toxicity, thallium is understudied and not regulated in food. The California Department of Public Health was alerted to a household cluster of elevated urine thallium levels noted among a mother (peak 5.6 µg/g creatinine; adult reference: ≤0.4 µg/g creatinine) and her three young children (peak 10.5 µg/g creatinine; child reference: ≤0.8 µg/g creatinine). Objectives: This case report identifies questions raised after a public health investigation linked a household’s thallium exposure to a commercially available food product. We provide an overview of the public health investigation. We then explore concerns, such as gaps in toxicological data and limited surveillance of thallium in the food supply, which make management of individual and population exposure risks challenging. Methods: We highlight findings from a cross-agency investigation, including a household exposure survey, sampling of possible environmental and dietary exposures (ICP-MS analysis measured thallium in kale chips at 1.98 mg/kg and 2.15 mg/kg), and monitoring of symptoms and urine thallium levels after the source was removed. We use regulatory and research findings to describe the challenges and opportunities in characterizing the scale of thallium in our food supply and effects of dietary exposures on health. Discussion: Thallium can bioaccumulate in our food system, particularly in brassica vegetables like kale. Thallium concentration in foods can also be affected by manufacturing processes, such as dehydration. We have limited surveillance data nationally regarding this metal in our food supply. Dietary reviews internationally show increased thallium intake in toddlers. Limited information is available about low-dose or chronic exposures, particularly among children, although emerging evidence shows that there might be risks associated at lower levels than previously thought. Improved toxicological studies are needed to guide reference doses and food safety standards. Promising action towards enhanced monitoring of thallium is being pursued by food safety agencies internationally, and research is underway to deepen our understanding of thallium toxicity. Full article

TYC 622-742-1 and TYC 1193-1918-1 are evolved metal-poor (MP) high-speed stars with r-enhanced characteristics discovered in the Milky Way (MW) halo. The study of these halo stars is important for clarification of and knowledge about their origin. We employ the abundance decomposition method to fit the observed abundances of 25 elements in TYC 622-742-1 and 24 elements in TYC 1193-1918-1, representing the largest number of elements fitted in the current observed dataset. We analyze the astrophysical formation sites of both sample stars by calculating their abundance ratios and component ratios. The calculation results suggest that both stars originated in a gas cloud that was contaminated by the ejecta of primary and main r-process materials such as those from a neutron star merger (NSM), which enriched their heavy neutron-capture elements (HNCEs), and the material from the massive stars ($M\ge 10M_{\odot }$), which enriched their primary light, iron-group, and lighter neutron-capture elements (LNCEs). This implies that TYC 622-742-1 and TYC 1193-1918-1 are the main r-process-enhanced stars with strong primary-process contributions. We find that the component coefficients of the sample stars closely resemble those of metal-poor Galactic populations, indicating a probable origin within the MW. Furthermore, the $\alpha$-enhanced abundance patterns and orbital trajectories suggest that both stars likely formed in the Galactic disk, possibly within a globular cluster (GC), and were subsequently ejected into the halo through dynamical processes. Full article

One hundred presumptive Pseudomonas isolates, recovered from 15 sites impacted by anthropogenic activity in the Foggia district (Italy), were screened for key adaptive and functional traits important for environmental applications. The isolates were phenotypically characterized for their ability to grow under combined pH (5.0–8.0) and temperature (15–37 °C) conditions, to produce proteolytic enzymes, pigments, and exopolysaccharides, and to tolerate SDS. Moreover, the resistance to six environmentally relevant heavy metals (Cd, Co, Cu, Ni, Zn, As) was qualitatively assessed. The results highlighted wide inter-strain variability, with distinct clusters of isolates showing unique combinations of stress tolerance, enzymatic potential, and resistance profile. PERMANOVA analysis revealed significant effects of both the isolation site and the metal type, as well as their interaction, on the observed resistance patterns. A subset of isolates showed co-tolerance to elevated temperatures and heavy metals. These findings offer an initial yet insightful overview of the adaptive diversity of soil-derived Pseudomonas, laying the groundwork for the rational selection of strains for bioaugmentation in contaminated soils. Full article