Search Results (159)

This study investigated how metal concentrations and microplastic abundance co-vary temporally and spatially in sediments in Durban Harbour, South Africa. The effects of sediment contamination on the amphipod Grandidierella lignorum was additionally investigated. Sediments from five sites in the harbour, namely Little Lagoon (LL), Yacht Bank (YB), Marina Bank (MB), Western Bank (WB), and Central Bank (CB), were analysed for metals using ICP-OES, and microplastic particles were counted. Sediment metal concentrations varied across sites and seasons, with Al and Fe dominating. Elevated levels of Cu, Zn, and Pb were observed, particularly in areas with high industrial activity, suggesting point-source contamination. Trace concentrations of As, Cd, and Ni were found and these metals were excluded from further analysis. Abundance ranged from 0.2 to 2.5 particles per gram dry weight, and differed significantly among sites (p < 0.01) with the highest concentrations in LL and YB. Amphipod survival rates following exposure to sediment did not significantly differ among sites but correlated moderately with microplastic abundance (p > 0.05, R² = 0.57). Tissue analysis revealed selective metal accumulation, following the trend Al > Fe > Zn > Cu > Cr, with Mn, As, and Pb undetected. These results highlight the spatial heterogeneity of sediment contamination in Durban Harbour and demonstrate the bioaccumulation potential and ability to regulate metals in G. lignorum, particularly for essential metals like Fe and Zn. Despite no clear evidence linking microplastics to metal concentrations, the findings highlight the complex interactions between contaminants and their potential ecological impact. Full article

The rare earth (RE) aqua 4-nitrophenylacetate (4npa) complexes {[RE(4npa)₃(H₂O)₂]·2H₂O}_n (RE = La (1La), Nd (2Nd)), [Ce(4npa)₃(H₂O)₂]_n (3Ce), and {[RE₂(4npa)₆(H₂O)]·2H₂O}_n (RE = Gd (4Gd), Dy (5Dy), Y (6Y), Er (7Er), Yb (8Yb)) were synthesised by salt metathesis reactions of RE^III chlorides or nitrates with sodium 4-nitrophenylacetate Na(4npa) in aqueous ethanol. The structures of all the complexes were determined by single-crystal X-ray diffraction (SCXRD) except for RE = 4Gd, which was determined to be isomorphous with the 5Dy and 7Er complexes by X-ray powder diffraction (XRPD). All the complexes crystallise as one-dimensional polymers linked by bridging carboxylates. Complexes (1La–3Ce) have mononuclear repeating units with two coordinated waters and ten coordinate RE ions, 1La and 2Nd also have two waters of crystallization, but 3Ce has none. By contrast, complexes (4Gd–8Yb) have binuclear repeating units with a single coordinated water. Isomorphous 5Dy and 7Er have one nine coordinate and one eight coordinate metal ion, whilst isomorphous 6Y and 8Yb have two eight coordinate RE ions. In some cases, bulk powders have structures different from the corresponding single crystals. For example, bulk 1La is isomorphous with 3Ce owing to the loss of water of crystallization, and 8Yb exhibits coordination isomerism between single crystals and microcrystalline powder. Weight loss corrosion tests revealed that {[Dy₂(4npa)₆(H₂O)]·2H₂O}_n (5Dy) has the greatest inhibition efficiency (89%) of the complexes (1La–8Yb). The activities are comparable to those of the corresponding 4-hydroxyphenylacetates (4hpa) and far superior to those of 2-hydroxyphenylacetates (2hpa) and the unsubstituted phenylacetates. Whilst the coordination numbers generally decline with the lanthanoid contraction, there are deviations around 5Dy, 6Y, 7Er, and 8Yb, and the corrosion inhibition is optimised with a midrange size. Full article

Precise remote temperature sensing at the micro- and nanoscale is a growing necessity in modern science and technology. We report a series of luminescent tris-acetylacetonate lanthanide complexes, Ln(acac)₃(H₂O)₂ (Ln = Eu (1Eu), Tb (1Tb), Yb (1Yb)); acac⁻ = acetylacetonate), operating as self-referenced thermometers in the 290–350 K range, both in the solid state and when embedded in hybrid nanoparticles. Among the investigated systems, the Eu³⁺ complex exhibits excellent lifetime-based thermometric performance, achieving a maximum relative sensitivity (S_rmax) of 2.9%·K⁻¹ at 340 K with a temperature uncertainty (δT) as low as 0.02 K and an average temperature uncertainty ($\overline{\delta T}$) of 0.5 K, placing it among the most effective ratiometric lanthanide-based luminescent thermometers reported to date. The Yb³⁺ analog enables intensity-based thermometry in the near-infrared domain with a good sensitivity S_rmax = 0.5%·K⁻¹ at 293 K, δT = 0.5 K at 303 K, and $\overline{\delta T}$ = 1.6 K. These molecular thermometers were further incorporated into the shell of Prussian Blue@SiO₂ core–shell nanoparticles. Among the resulting hybrids, PB@SiO₂-acac/(1Tb/1Eu) (with a Tb/Eu ratio of 2/8) stood out by enabling ratiometric temperature sensing based on the Eu³⁺⁵D₀ → ⁷F₂ lifetime, with satisfactory parameters (S_rmax = 0.9%·K⁻¹, δT = 0.21 K at 303 K, and $\overline{\delta T}$ = 1.1 K). These results highlight the potential of simple coordination complexes and their nanohybrids for advanced luminescent thermometry applications. Full article

Achieving high quantum yields for Yb³⁺ ion emission in complexes with organic ligands is a challenging task, as most Yb³⁺ complexes with such ligands typically exhibit efficiencies below 3.5%. Our research demonstrates that the introduction of heavy atom-containing ancillary ligands, such as TPPO or TPAO, along with the careful engineering of the main β-diketone ligand, can increase the luminescence efficiency up to 20-fold by the alteration of the energy migration pathway. It is demonstrated that the combination of two distinct organic ligands leads to the blockage of singlet–triplet intersystem crossing (ISC), alongside electronic energy transfer from β-diketone to Yb³⁺ ions through charge transfer states. The synthesized complexes exhibit quantum yields of 6.5% and 7.0% in the solid state, which places them at the top globally among this class of materials with simple non-deuterated and non-fluorinated ligands. Full article

Tomato (Solanum lycopersicum) is a globally important crop, and enhancing its fruit quality and phenotypic traits is a key objective in modern breeding. This study investigates the role of the LEAFY-COTYLEDON1-LIKE4 (L1L4), an NF-YB subunit of the nuclear factor Y (NF-Y) transcription factor, in tomato fruit development using RNA-sequencing data from zinc-finger nuclease (ZFN)-targeted disruption lines. Differential gene expression (DEG) analyses of two independent l1l4 mutant lines compared to the wild-type line revealed significant alterations in key metabolic pathways and regulatory networks that are implicated in fruit ripening. Specifically, L1L4 disruption impacted the genes and pathways related to the fruit’s color development (carotenoid and flavonoids), texture (cell wall modification), flavor (sugar and volatile organic compound metabolism), and ripening-related hormone signaling. The analyses also revealed multiple differentially expressed histones, histone modifiers, and transcription factors (ERFs, MYBs, bHLHs, WRKYs, C2H2s, NACs, GRAS, MADs, and bZIPs), indicating that L1L4 participates in a complex regulatory network. These findings provide valuable insights into the role of L1L4 in orchestrating tomato fruit development and highlight it as a potential target for genetically improving the fruit quality. Full article

NF-Y transcriptional regulators play crucial roles in diverse biological processes in plants, primarily through the formation of NF-Y complexes that bind to specific DNA motifs. These complexes modulate the expression of downstream genes, which influence plant development and growth. In our research, the function of the NF-Y family C subunit member SlNF-YC9 gene in tomato was investigated with the CRISPR/Cas9 method. In contrast to the WT (wild type), the mutant CR-SlNF-YC9 exhibited a prominent protrusion at the fruit tip. The quantitative PCR analysis displayed that the transcription levels of genes associated with auxin transport (PIN4, PIN5, and PIN9) as well as auxin response genes (ARF7 and LAX3) were enhanced in the CR-SlNF-YC9 fruits than in the WT. Analysis of dual-luciferase reporter and EMSA assays showed that the SlNF-YC9-YB13b-YA7a trimer specifically binds the FUL2 promoter and represses its expression. In conclusion, our results suggest that SlNF-YC9 is crucial in influencing tomato fruit shape by the formation of NF-Y heterotrimeric complexes. Full article

This study explores the provenance of white marble architectural elements from Roman Philippopolis, with a particular focus on the Eastern Gate complex. By determining the origin of the marble, we aim to elucidate economic, social, and urban dynamics related to material selection and trade networks. The investigation examines the symbolic significance of prestigious marble in elite representation and highlights the role of quarry exploitation in the region’s economic and technological development. The Eastern Gate, a monumental ensemble integrated into the city’s urban fabric, was primarily constructed with local Rhodope marble, alongside imported materials such as Prokonnesian marble. Analytical methods included petrographic examination, chemical analysis of trace elements (Mn, Mg, Fe, Sr, Y, V, Cd, La, Ce, Yb, and U), and stable isotope analysis (δ¹⁸O, δ¹³C). Statistical evaluations were performed for each sample (37 in total) and compared with a comprehensive database of ancient quarry sources. The results underscore the dominance of local materials while also indicating selective use of imports, potentially linked to symbolic or functional criteria. The findings support the hypothesis of local workshop activity in the Asenovgrad/Philippopolis area and shed light on regional and long-distance marble trade during the Roman Imperial period, reflecting broader economic and cultural interconnections. Full article

Late Paleozoic to Early Mesozoic granitoids in the East Kunlun Orogenic Belt (EKOB) provide critical insights into the complex and debated relationship between Paleo–Tethyan magmatism and tectonics. This study presents integrated bulk-rock geochemical and zircon isotopic data for the Xingshugou monzogranite (MG) to address these controversies. LA-ICP-MS zircon U-Pb dating constrains the emplacement age of the MG to 247.1 ± 1.5 Ma. The MG exhibits a peraluminous and low Na₂O A₂-type granite affinity, characterized by high K₂O (4.69–6.80 wt.%) and Zr + Nb + Ce + Y (>350 ppm) concentrations, coupled with high Y/Nb (>1.2) and A/CNK ratios (1.54–2.46). It also displays low FeO^T, MnO, TiO₂, P₂O₅, and Mg^# values (26–49), alongside pronounced negative Eu anomalies (Eu/Eu* = 0.37–0.49) and moderately fractionated rare earth element (REE) patterns ((La/Yb)_N = 3.30–5.11). The MG exhibits enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs; such as Sr and Ba), and depletion in high field strength elements (HFSEs; such as Nb, Ta, and Ti), collectively indicating an arc magmatic affinity. Zircon saturation temperatures (T_Zr = 868–934 °C) and geochemical discriminators suggest that the MG was generated under high-temperature, low-pressure, relatively dry conditions. Combined with positive zircon ε_Hf(t) (1.8 to 4.7) values, it is suggested that the MG was derived from partial melting of juvenile crust. Synthesizing regional data, this study suggests that the Xingshugou MG was formed in an extensional tectonic setting triggered by slab rollback of the Paleo-Tethys Oceanic slab. Full article

The structural complexity and variability of dissolved organic matter (DOM) significantly affect its binding capacity with heavy metals (HMs). This study evaluated the remediation efficacy of biochar (BC) and humic acid (HA) on Mn- and Cu-contaminated soils using four maize pot treatments: 3% BC (YB3), 6% BC (YB6), 3% BC + 1% HA (YB3H), and 6% BC + 1% HA (YB6H). The results showed that compared to the control (Y), Results showed Mn and Cu concentrations in rhizosphere soil decreased by 11.08–17.76%, while DOM content increased by 44.2–103.83%. BC enhanced DOM aromaticity and humification, further intensified by HA, leading to a more complex and stable DOM structure. PARAFAC identified four DOM components in BC (BC-DOM): C1 (fulvic-like), C2/C3 (humic-like), and C4 (protein-like), and in BC + HA (BC + H-DOM), an enhanced structural complexity with additional aromatic C–H groups was observed. 2D-COS analysis revealed that in BC-DOM, polysaccharides primarily interacted with Mn and Cu, followed by carboxylic acids and phenolic hydroxyl groups, but in BC + H-DOM, aromatic C–H groups preferentially bound Cu before polysaccharides, showing weaker affinity for Mn. These results elucidate the DOM-mediated immobilization mechanisms of BC and HA for HMs, offering insights for soil remediation and carbon sequestration strategies. Full article

Organometallic rare-earth complexes have attracted considerable attention in recent years due to their unique structures and exceptional magnetic properties. In this study, we report the synthesis and magnetic characteristics of a family of monopentamethylcyclopentadienyl-coordinated trinuclear rare-earth hepta-chloride clusters [(Li(THF)(Et₂O))(Cp^*RE)₃(μ-Cl)₄(μ₃-Cl)₂(μ₄-Cl)] (RE₃: RE =Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu; Cp* = pentamethylcyclopentadienide). These clusters were synthesized by reacting LiCp* with RECl₃ in a 1:1 molar ratio within a mixed solvent system (THF: Et₂O = 1:9), resulting in high solubility in common organic solvents such as DCM, THF, and Et₂O. Magnetic studies conducted on these paramagnetic clusters reveal the coexistence of ferromagnetic and antiferromagnetic superexchange interactions in Gd₃. Additionally, Dy₃ exhibits both ferromagnetic and antiferromagnetic intramolecular dipolar interactions. Notably, slow magnetic relaxation was observed in Dy₃ below 23 K under a zero DC applied field with an energy barrier of 125(6) cm⁻¹. Full article

This study presents the synthesis of NaYF₄: Er³⁺/Yb³⁺ upconversion luminescent nanomaterials using a wet chemistry method. The role of oleic acid in influencing the size, shape, and luminescent properties of the materials was also investigated. The results showed that, at a suitable oleic acid concentration of 10⁻³ M, the obtained nanoparticles exhibited a nearly spherical morphology with diameters ranging from 150 to 250 nm and predominantly display a hexagonal (β-NaYF₄) crystalline phase. Photoluminescence measurements under 980 nm laser excitation reveal that these nanoparticles emit strong, stable luminescence with narrow emission bands characteristic of Er³⁺ transitions. Subsequently, the nanoparticles were coated with a silica shell, functionalized with amine groups, and conjugated with IgG antibodies via glutaraldehyde (GA) to form the bio-nano complex β-NaYF₄: Er³⁺/Yb³⁺@SNGA-IgG. In vitro experiments using fluorescence microscopy demonstrated that the complex effectively labels HeLa cervical cancer cells. With its robust upconversion luminescence and excellent biocompatibility, the developed nanocomplex shows promising potential for rapid pathogen detection and other biomedical applications. Full article

A variety of variables, such as organic matter input, redox conditions, depositional rates, and terrigenous input, affect the deposition of black shale. Furthermore, because of the significant regional variations in paleodepositional environments, these factors have a complex role in organic matter enrichment. Global geological events influenced sedimentary conditions, organic enrichment, and the development of organic-enriched shales during the Late Ordovician to Early Silurian. The Wufeng–Longmaxi Formation black shales in Southeastern Chongqing were analyzed for X-ray diffraction (XRD), major and trace element geochemistry, and total organic carbon (TOC) data; this led to further analysis of the relationship between the depositional environment and organic matter aggregation and rock type evolution. The primary minerals found in the Wufeng–Longmaxi shale are quartz, feldspar, carbonatite (calcite and dolomite), and clay. The high index of compositional variability (ICV) values (>1) and the comparatively low chemical index of alteration (CIA) values (52.6–72.8) suggest that the sediment source rocks are juvenile and are probably experiencing weak to moderate chemical weathering. The selected samples all show negative Eu anomalies, flat heavy rare earth elements, and mildly enriched light rare earth elements. The ratios of La/Th, La/Sc, Th/Sc, ΣREE-La/Yb, TiO₂-Ni, and La/Th-Hf suggest that acidic igneous rocks were the main source of sediment, with minor inputs from ancient sedimentary rocks. The correlations of paleoclimate proxies (Sr/Cu, CIA), redox proxies (V/Cr, V/Ni, V/(V + Ni), Ni/Co, U/Th), paleoproductivity proxies (Ba_xs, Cu_EF, Ni_EF), and water mass restriction proxies (Mo/TOC, U_EF, Mo_EF) suggest a humid–semiarid, anoxic, moderate–high paleoproductivity, and moderate–strongly restricted environment. On the basis of the aforementioned interpretations, the paleoenvironment of the Wufeng–Longmaxi Formations was established, with paleoredox conditions and restricted water masses likely being the primary factors contributing to organic matter enrichment. Full article

This study systematically investigated the extraction and separation of ytterbium (Yb) and nickel (Ni) from manganese (Mn)- and calcium (Ca)-containing heavy metal solutions using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (HEHEHP) in nitric acid media. Results demonstrated that the logarithms of distribution ratios for Yb, Ni, Mn, and Ca exhibited positive correlations with both solution pH and the logarithm of extractant concentration, consistent with theoretical models. Elevated initial metal concentrations reduced distribution ratios for all elements, indicating extraction inhibition. Ytterbium back-extraction efficiency increased proportionally with hydrochloric acid concentration and the number of back-extraction stages. Optimization of key extraction parameters established predictive equilibrium relationships: Yb/Ni and Mn/Ca separation coefficients increased with decreasing acidity and extractant concentration, whereas Mn/Ni and Ca/Ni coefficients rose under higher acidity and extractant conditions. Infrared spectroscopy confirmed HEHEHP-Yb complexation mechanisms, with extractant stability retained through multiple reuse cycles. Optimized cascade processing parameters (3 extraction stages, 3 washing stages, 4 back-extraction stages) achieved >99.9% purity for both Yb and Ni. This validated methodology provides a robust technical framework for heavy metal waste treatment and high-value element recovery. Full article

Carbonaceous shale has garnered significant interest as a viable alternative source of rare earth elements (REEs) besides conventional REE-bearing ores. This study characterized rare earth element + Yttrium+ Scandium (REYs) enrichment in the 11 core samples of carbonaceous shale (7) and coal (4) collected from Arnot Mine. Major elements of the studied carbonaceous shale (CS) and coal showed high amounts of SiO₂, Al₂O₃, and Fe₂O₃, indicating a high content of aluminosilicate and iron-rich minerals. The plots Na₂O + K₂O against SiO₂ suggested alkali granite, granite, and granodiorite provenance sources for the studied shale and coal. The samples showed enrichment in low and heavy rare elements crystallized from a low potassium tholeiitic and medium calc-alkaline magma based on the plots of La_N/Yb_N and K₂O vs. SiO₂. The mineralogical and maceral analysis revealed the dominant presence of kaolinite (15%–45%), and it was suggested as the cation exchange site resulting from the isomorphous substitution of Al³⁺ for Si⁴⁺. Additionally, siderite was suggested as one of the REY hosts due to the Fe³⁺ site forming a complex with the REE³⁺ ions. Furthermore, the samples were classified as lignite to sub-bituminous coal category with dominant minerals including kaolinite, quartz, and siderite. The outlook coefficient (Coutl) of REY in CS revealed a promising area for economically viable, having two enrichment types, including low (La, Ce, Pr, Nd, and Sm) and heavy (Ho, Er, Tm, Yb, and Lu). The Eu_N/Eu_N* and Ce_N/Ce_N* ratio for the current studied samples exhibited a weak negative to no anomaly, and most of the studied samples were characterized by distinctive positive Gd anomalies derived from sediment source regions weathered from alkali granite, granite, and granodiorite provenance formed from a low potassium tholeiitic and medium calc-alkaline magma. Full article

The connection between crustal anatexis and magmatism is key to understanding the mechanisms that drive the evolution of the continental crust. Isotope geology and lithochemistry are important tools for reconstructing links between these processes, as field evidence of their connection is often obliterated by deformation in high-grade terrains. Thus, this study proposes new insights into the connection between the Mesoarchean regional metamorphism, crustal anatexis, and plutonism in the northern sector of the Carajás Province (i.e., Carajás Domain), in the Amazonian Craton, around 2.89 to 2.83 Ga. The widespread crustal anatexis in the Carajás Domain involved the water-fluxed melting of banded orthogneisses of the Xingu Complex and Xicrim-Cateté Orthogranulite (crystallization age at ca. 3.06–2.93 Ga), producing metatexites and diatexites with stromatic, net, schollen, and schlieren morphologies and coeval syntectonic leucosomes with composition similar to tonalites, trondhjemites, and granites. These leucosomes yielded crystallization ages of 2853 ± 5 Ma (MSWD: 0.61), 2862 ± 13 Ma (MSWD: 0.1), and 2867 ± 7 Ma (MSWD: 1.3). Their lithochemical data are similar to those of several diachronous Mesoarchean granitoids of the Carajás Domain in terms of major, minor, and trace elements and magmatic affinity. In addition, binary log–log vector diagrams (e.g., La vs. Yb; Rb vs. Yb), Sr/Y vs. Y, and Eu/Eu* vs. Yb plots indicate that plagioclase fractionation preceded melt extraction, establishing evolving source-to-sink trends between leucosomes and granites. These results show that the interplay between high-grade metamorphism, crustal anatexis, and magmatism may have shaped the evolution of the Mesoarchean continental crust in the Carajás Province, developing a petrotectonic assemblage associated with collisional orogens. The Mesoarchean geodynamic setting played a critical role in the development of coeval ca. 2.89 Ga magmatic–hydrothermal copper deposits in the Carajás Province, as well as Neoarchean world-class iron oxide–copper–gold deposits linked to post-orogenic extensional rebound. Full article