Search Results (519)

Background/Objective: Clinical statistics show that bacterial infection is a major driver of implant failure. To enhance antibacterial performance, some metallic elements, such as silver (Ag), zinc (Zn), and copper (Cu), are commonly used to modify the titanium surface. Despite the promising antibacterial performance of Ag, concerns persist regarding dose-dependent cytotoxicity, systemic accumulation, and potential effects on local bone metabolism. This review aimed to investigate the effects of incorporating or coating titanium (Ti) implant surfaces with Ag on bone formation around implants. Methods: A search was undertaken using three main databases (PubMed, Web of Science, and Scopus). The search was limited to studies published within the last 20 years that involved animal experiments using endosseous implants coated with or incorporating Ag. Meta-analyses were performed for bone-to-implant contact (BIC), bone formation (BA), and bone volume (BV/TV) around the implant in control and test groups. The compared groups were subjected to similar implant surface treatments aside from the presence of silver in the test group. Results: Sixteen studies met the inclusion criteria in this study and were included. The analysis of BIC values revealed a statistically significant overall effect in favor of silver-coated implants (Z = 2.01, p = 0.04), along with 95% confidence intervals (CIs). The BA analysis found no significant difference between silver-coated and control implants (Z = 1.09, p = 0.28). The BV/TV analysis also showed no statistically significant overall difference (Z = 0.35, p = 0.73). Conclusions: In animal models, silver-coated Ti implants improve bone–implant contact without altering peri-implant bone volume metrics. Full article

2,2-Bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethanol (HL) is a heteroscorpionate ligand capable of coordinating metal ions through two nitrogen atoms and one oxygen atom. We report a base free synthetic route to metal complexes of L and explore the resulting structural diversity. Notably, complex composition varies substantially depending on the metal ion, including dinuclear molybdenum species and distinct coordination behavior with silicon and copper. The isolated compounds include the dinuclear, oxygen-bridged complexes (LMoO₂)₂O and (LMoO)(μ-O)₂, as well as the mononuclear complexes LTi(NMe₂)₃, LZrCl₃, LGeCl₃, LWO₂Cl, LCu(acetate)₂H, and LSiMe₂Cl. Single crystal X-ray diffraction reveals that the bulky complex structures generate cavities in the crystal lattice, frequently occupied by solvent molecules. The titanium, zirconium, molybdenum, tungsten, and germanium complexes exhibit octahedral coordination, while structural peculiarities are observed for copper and silicon. The copper(II) complex shows a distorted octahedral geometry with one elongated ligand bond; the silicon complex is pentacoordinated in the solid state. Additional characterization includes melting points, NMR, and IR spectroscopy. The developed synthetic strategy provides a straightforward and versatile route to heteroscorpionate metal complexes. Full article

Sulfonamides represent a versatile class of biologically active compounds, best known for their antibacterial activity, but increasingly investigated for their potential in oncology. Free sulfonamides themselves display cytotoxic properties; however, coordination with metal ions often enhances both selectivity and potency, while also introducing new mechanisms of action. Although numerous studies have reported sulfonamide–metal complexes with anticancer activity, a systematic overview linking biological properties to the central metal atom has been lacking. This review summarizes current research on sulfonamide complexes with transition metals and selected main-group elements, focusing on their pharmacological potential as anticancer agents. The compounds discussed include complexes of titanium, chromium, manganese, rhenium, ruthenium, osmium, iridium, palladium, platinum, copper, silver, gold, iron, cobalt, nickel, uranium, calcium, magnesium and bismuth. For each group, representative structures are presented along with cytotoxicity data against cancer cell lines, comparisons with reference drugs such as for example cisplatin, and where relevant, studies on carbonic anhydrase inhibition. The survey of available data demonstrates that many sulfonamide–metal complexes show cytotoxic activity comparable to or greater than existing chemotherapeutic agents, while in some cases exhibiting reduced toxicity toward non-cancerous cells. These findings highlight the promise of sulfonamide–metal complexes as a fertile area for anticancer drug development and provide a framework for future design strategies. This review covers the research on anti-cancer activity of sulfonamide complexes during the years 2007–2025. Full article

The incomplete degradation of degradable plastics may pose potential ecological risks, as it can generate degradable microplastics (DMPs), especially when these DMPs coexist with heavy metals in soil. Taking petrochemical-based poly(butylene adipate-co-terephthalate) (PBAT) and bio-based polylactic acid (PLA) as representative DMPs, this study investigated how DMPs affect the adsorption–desorption behavior of Cu²⁺ in soil and the underlying mechanisms via batch equilibrium experiments and characterization analyses. The experiments revealed that ion exchange (accounting for 33.6–34.3%), oxygen-containing functional group complexation, and electrostatic interactions were the primary adsorption driving forces, with chemical adsorption playing the main role. Compared to the soil, the PBAT and PLA had smaller specific surface areas and pore volumes, fewer oxygen-containing functional groups, and especially lacked O-metal functional groups. They can dilute soil, clog its pores, and cover its active sites. 1% DMPs significantly reduced the soil’s equilibrium adsorption capacity (Q_e) (3.7–4.7%) and increased equilibrium desorption capacity (Q_De) (1.7–2.6%), thereby increasing the mobility and ecological risk of Cu²⁺. PBAT and PLA had no significant difference in effects on the adsorption, but their specific mechanisms were somewhat distinct. Faced with the prevalent, worsening coexistence of DMPs and heavy metals in soil, these findings contribute to the ecological risk assessment of DMPs. Full article

Quinazolin-4(3H)-ones are nitrogen heterocycles that have attracted considerable interest over many years due to their important biological and pharmacological properties. It has been shown that quinazolinone derivatives exhibit, e.g., analgesic, anti-inflammatory, antibacterial, anticonvulsant, antifungal, and antitumor activities. Some of these compounds have found applications in medicine; for instance, Zydelig (Idelalisib) has been approved for the treatment of several types of blood cancers. Furthermore, the quinazolinone skeleton is an important structural moiety present in many naturally occurring alkaloids, such as Febrifugine, a potent anti-malarial agent. To date, numerous synthetic methods have been developed for the synthesis of quinazolinone derivatives. Among them, multicomponent reactions (MCRs) have emerged as a powerful tool, allowing for the rapid and straightforward construction of the quinazolinone scaffold from readily available substrates. This review article presents a concise overview of selected strategies for synthesizing quinazolinone frameworks via one-pot MCRs. The reported methods are categorized into three main groups: metal-catalyzed reactions; isatoic-anhydride-based strategies, utilizing isatoic anhydride as a key starting material, and alternative approaches involving, among others, the utilization of N-(2-aminobenzoyl)benzotriazoles or aryldiazonium salts as efficient building materials. Full article

Physiographic, geographic, and environmental gradients influence the development of plant communities. This study assessed how environmental gradients affect riparian vegetation along the River Panjkora, aiming to find relationships between vegetation and abiotic factors through indicator species analysis. Vegetation was sampled using the quadrat method (1 × 1 m² for herbs, 5 × 5 m² for shrubs, 10 × 10 m² for trees), and soil samples were analyzed for edaphic variables. Indicator species and ordination analyses were performed using PCORD (version 5) and CANOCO (version 4.5) software to understand species diversity. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) identified species patterns and their links to environmental factors. A total of 216 plant species were recorded across seven stations, grouped into five communities. Community 01, Melia azedarach, Punica granatum, and Asparagus racemosus, are affected by Cr, p ≤ 0.03; Fe, p ≤ 0.01; Zn, p ≤ 0.04; and Mg, p = 0.03. On the other hand, Community 02, Populus alba, Debregeasia saeneb, and Youngia japonica, are controlled by Co, p = 0.01; pH, p = 0.03; Cd, p = 0.04; EC, p = 0.03; and TDSs, p = 0.03. The third community, with indicator species Pinus roxburghii, Rydingia limbata, and Cheilanthes pteridioides, is strongly influenced by Cr, p ≤ 0.05; Cu, p ≤ 0.03; TDSs, p = 0.02; and Zn, p = 0.03. Community 04, consisting of Ficus carica, Polygonum plebeium, and Avena sativa, is shaped by Na, p = 0.01; K, p ≤ 0.05; and Fe, p = 0.04. The fifth community, represented by Ficus palmata, Rosa multiflora, and Heliotropium europaeum, is influenced by pH, p ≤ 0.04 and Mn, p = 0.03. DCA displayed maximum gradient lengths of 6.443 (eigenvalue 0.742) on axis 1, 5.222 (0.662) on axis 2, 4.053 (0.600) on axis 3, and 4.791 (0.464) on axis 4. Soil pH, heavy metals (Cr, Fe, Zn, Mg, Co, Cd, Cu, Na, K, and Mn), EC, and TDSs were the main factors shaping community structure. The indicator species analysis is recommended to identify and conserve the rare species and native flora of a particular region. Full article

The Nujiang region of Yunnan is by far the richest tourmaline-producing mining area in China. Since the discovery of the tourmaline-bearing deposit in Yunnan Province in 1980, there have been few comprehensive gemmological studies of this deposit. Therefore, the results of tests on 32 tourmaline samples from the Fugong and Gongshan regions of Yunnan are reported in this paper. The chemical composition of the Yunnan tourmalines was analyzed, and the contents of major trace elements were compared with those of tourmaline samples from different localities reported in the literature to highlight their specific provenance characteristics. Microscopic observation revealed the presence of liquid, gas, and solid inclusions; Raman spectra indicated the presence of constitutional water and CH₄-C₂H₆ dihydrate in the Yunnan tourmalines and also pointed to the influence pattern of the Fe content. The infrared spectrum in the range of 4000–4800 cm⁻¹ showed the frequency of metal cations and hydroxyl groups. Based on the characteristic peaks at 4343 cm⁻¹ and 4600 cm⁻¹, a quick distinction between elbaite and dravite could be made. UV–Vis absorption spectroscopy analysis showed that in yellow tourmalines, Mn²⁺-Ti⁴⁺ IVCT is the main cause of color, while green coloration occurs due to Fe²⁺–Fe³⁺ interactions or Cr³⁺ and V³⁺, and the pink color is caused by Mn³⁺ d-d transitions. The three-dimensional fluorescence spectra revealed the presence of the main fluorescence peaks at λex280/λem320 nm and λex265/λem510 nm in the tourmaline samples analyzed and the fluorescence intensity with Ti and Fe contents. Full article

As work continues unabated in the study of noncovalent bonding, particularly σ-hole bonds, new challenges have emerged as the participation of transition metals in interactions of this sort is fast becoming appreciated. While there are certain similarities with the halogen, chalcogen, etc, bonds, in which the main group elements participate, there are certain unique properties of these metal atoms that must be analyzed before a complete understanding can be attained. As one example, these atoms tend to act simultaneously as both electron donors and acceptors, a synergistic action that amplifies the overall bond strength. Ideas are expressed in this paper to hopefully guide future work in this exciting new arena. Full article

The rising level of atmospheric carbon dioxide (CO₂) is a major driver of climate change, highlighting the need to develop carbon capture and storage (CCS) technologies quickly. This paper offers a comparative review of three main groups of porous adsorbent materials—zeolites, metal–organic frameworks (MOFs), and activated carbons—for their roles in CO₂ capture and long-term storage. By examining their structural features, adsorption capacities, moisture stability, and economic viability, the strengths and weaknesses of each material are assessed. Additionally, five different methods for delivering these materials into depleted oil and gas reservoirs are discussed: direct suspension injection, polymer-assisted transport, foam-assisted delivery, encapsulation with controlled release, and preformed particle gels. The potential of hybrid systems, such as MOF–carbon composites and polymer-functionalized materials, is also examined for improved selectivity and durability in underground environments. This research aims to connect materials science with subsurface engineering, helping guide the selection and use of adsorbent materials in real-world CCS applications. The findings support the optimization of CCS deployment and contribute to broader climate change efforts and the goal of achieving net-zero emissions. Key findings include CO₂ adsorption capacities of 3.5–8.0 mmol/g and surface areas up to 7000 m²/g, with MOFs demonstrating the highest uptake and activated carbons offering cost-effective performance. Full article

Background/Objectives: Guided bone regeneration one of the most widely used techniques, relies on combining bone graft material with barrier membranes or meshes. The choice of the mesh material depends on the specific clinical situation. Among the available options, titanium membranes are recognized as one of the most effective in dental implantology. The latter can be categorized into two groups: commercial and individualized. Advancements in additive manufacturing make customized titanium meshes an attractive option for bone regeneration. Customized titanium meshes can be manufactured using three main methods: selective laser sintering (SLS), selective laser melting (SLM), and direct metal laser sintering (DMLS). This review aims to provide information about the differences between the production process and the clinical outcomes. Methods: This systematic review was conducted by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Scoping Reviews (PRISMA-ScR). Relevant articles were sought out in the Web of Science, PubMed, and Scopus databases. Results: A total of ten articles were included and thoroughly reviewed. The type of bone graft used, the manufacturing technique, the amount of bone gain, the healing time, and the intraoperative and postoperative complications are discussed. Conclusions: All the relevant studies demonstrated good and predictable results using augmentation with individualized titanium meshes manufactured via SLS, SLM, or DMLS methods. 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

Titanium, the second most abundant and one of the cheapest, non-toxic transition metals in the Earth’s crust, is highly favorable for catalytic applications due to its widespread availability, low cost, low toxicity, and well-documented biocompatibility. However, because of its high affinity for oxygen and inherent Lewis acidity, titanium complexes generally exhibit lower tolerance toward various functional groups compared with complexes of later transition metals. The incorporation of cyclopentadienyl ligands significantly enhances the structural tunability of these complexes in their 3D configuration. By modifying the ligand framework, it is possible to fine-tune the Lewis acidity of the central titanium atom as well as the lability and binding characteristics of the ligands. This strategy enables precise control over the catalytic performance of titanocene complexes. The main body of this review provides an overview of recent advances in titanocene catalysis within the field of chemical synthesis since 2019. It includes illustrative examples that demonstrate the substrate scope and practical applications of titanocene catalysts in the synthesis of complex organic molecules and natural products. Finally, the review outlines current research opportunities and strategic directions for future developments in titanocene-based catalysis. Full article

Twenty-nine sediment samples were collected from Hurghada Bay, a highly impacted coastal area along the Northern Red Sea of Egypt, to evaluate environmental quality and human-induced effects on benthic ostracods. As potential bioindicators, benthic ostracods are highly responsive to environmental disturbances, with pollution leading to reduced abundance, lower diversity, and increased opportunistic taxa. To investigate the link between ostracod assemblages and sediment contamination, we measured the concentrations of eight heavy metals (Cu, Cd, Zn, Pb, As, Cr, Ni, and Mn) using inductively coupled plasma–atomic emission spectrometry (ICP-AES). Multivariate statistical analyses identified three distinct ostracod assemblages distributed across three station groups with varying pollution levels. Group I, associated with offshore stations, exhibited low to moderate heavy metal (HM) concentrations and high ostracod abundance and was dominated by Moosella striata, Hiltermannicythere rubrimaris, Ruggieria danielopoli, Neonesidea schulzi, and Paranesidea fracticorallcola, where the water depth and sand content are the main controlling factors. In contrast, Group II, corresponding to stations with the highest HMs and total organic matter (TOM), was dominated by pollution-tolerant species Jugosocythereis borchersi, Cyprideis torosa, Alocopocythere reticulata, and, to a lesser extent, Ghardaglaia triebeli, with reduced ostracod density and diversity. Group III, characterized by stations influenced by the mud-controlling factor, had the lowest HMs and was dominated by pollution-sensitive species Xestoleberis rhomboidei, Paranesidea fortificata, and Loxocorniculum ghardaquensis. These findings highlight the ecological risks posed by HM pollution and emphasize the urgent need for pollution mitigation strategies and continued monitoring to preserve the Red Sea’s benthic biodiversity. 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

Trace metal pollution in tropical freshwater ecosystems poses growing public health concerns, particularly in regions where fisheries are central to food security; however, little is known about metal exposure risks in the Western Amazon. This study presents the first assessment of trace metal concentrations in fish sold at the main market in El Coca, a rapidly growing city in the Ecuadorian Amazon. We analyzed 11 trace metals in 17 commercially important species and estimated seven health risk indices based on two fish consumption scenarios and international reference dose standards. Our results show that all species exceeded recommended thresholds for arsenic, mercury, and lead, while one species surpassed guidelines for aluminum. Metal concentrations varied by species and river of origin: small catfish from the Payamino River had elevated cadmium, chromium, copper, and manganese levels, potentially linked to upstream gold mining, whereas larger catfish showed higher mercury and arsenic accumulation. Monte Carlo simulations of risk indices suggested overall some disease risk, but the lack of local demographic data limits accurate assessments for vulnerable groups. Despite sampling limitations, our findings offer the first baseline for monitoring trace metal exposure in the northern Ecuadorian Amazon and underscore the need for targeted public health strategies in this understudied region. Full article