Search Results (444)

Newly constructed regulation reservoirs experience dramatic seasonal environmental shifts, yet the temporal dynamics of their aquatic food webs remain poorly understood. In this study, we investigated the seasonal variations in fish community structure and trophic niches in Xianlin Reservoir (Zhejiang, China) using catch surveys and stable isotope analysis (δ¹³C and δ¹⁵N). Our results revealed that the fish assemblage was persistently dominated by the non-native fish Lepomis macrochirus and the native Xenocypris argentea. Community-wide isotopic metrics, calculated via SIBER, demonstrated pronounced seasonal plasticity in the trophic architecture. During winter, driven by limited basal resources, the community exhibited a “dietary expansion” strategy, resulting in the longest vertical food chain, the broadest core isotopic niche area (SEAc = 16.33), and the lowest trophic redundancy (indicated by the highest mean nearest neighbor distance). Conversely, the spring community displayed a highly compressed trophic structure characterized by dense species packing and maximum redundancy. These findings highlight that the reservoir food web exhibits a reduced functional buffering capacity during winter due to weak functional substitutability among high-trophic-level species. Given the ongoing community assembly in this newly constructed reservoir, the system is potentially more susceptible to seasonal environmental perturbations. Full article

Driven by the demand for miniaturization, high capacitance, and enhanced reliability in high-performance multilayer ceramic capacitors (MLCCs), the continuous thinning of inner electrode layers imposes increasingly stringent requirements on the size, distribution, morphology, and dispersion of nano-nickel powders. We systematically investigate how functional additives regulate the nucleation, growth, and microstructural evolution of nano-nickel synthesized via hydrazine-driven liquid-phase reduction of nickel sulfate. The results demonstrate that the alkanolamine complexing agent (TAC) significantly refines the average particle size and morphology of the nano-nickel through coordination effects. Furthermore, inorganic sulfur salts (ISP), acting via surface adsorption to passivate growth sites and provide catalytic effects, enable a precise and continuous reduction in the average particle diameter from 330 nm down to 60 nm at a mere trace dosage of ~10⁻⁷ mol/L. Regarding dispersion optimization, highly dispersed face-centered cubic (FCC) nano-nickel was successfully prepared by introducing multidentate carboxylate (NNA). High-resolution transmission electron microscopy (HRTEM) was employed to unveil, for the first time, the crystallographic origin of the anomalous surface protrusions typically observed in conventional reaction systems. We confirmed that the family of $\left\{10\overline{1}0\right\}$ crystal planes within these regions, which exhibits interfacial angles of 58.7° and 58.3°, corresponds to a thermodynamically metastable hexagonal close-packed (HCP) nickel phase originating from atomic stacking faults induced by rapid growth kinetics. To address this microstructural defect, a thioether-based amino acid (TAA) was introduced. TAA effectively suppresses the anisotropic growth of the metastable HCP phase through the strong steric hindrance of its long side chains and its selective adsorption onto high-energy facets. Full article

Poly(9,9-di-n-octylfluorene) (PFO) suffers from interchain aggregation, which degrades its blue spectral stability and charge transport. To address this, a series of rod-coil diblock copolymers (PFO-b-PMMAs) with varying poly(methyl methacrylate) (PMMA) chain lengths were synthesized via Steglich coupling. The non-conjugated PMMA blocks act as bulky steric spacers in the solid state, effectively suppressing detrimental PFO aggregation and enhancing pure blue emission stability. Furthermore, moderate PMMA blocks (PFO-b-PMMA1 and PFO-b-PMMA2) promote favorable β-phase formation and ordered crystalline packing. This microstructural optimization yields a maximum electron mobility of 1.98 × 10⁻⁶ cm²/(V·s) for PFO-b-PMMA2, markedly higher than the PFO-2 homopolymer (4.13 × 10⁻⁷ cm²/(V·s)). However, an overlong PMMA block (PFO-b-PMMA3) introduces excessive steric hindrance (T_g = 66 °C) that disrupts crystallization, acting as an insulating barrier that reduces mobility. Thus, precisely tuning the non-conjugated block length effectively maximizes both the blue spectral stability and electron transport capabilities of PFO-based materials. Full article

Beef production is widely recognized as a significant contributor to global greenhouse gas emissions, making robust and transparent environmental assessments essential for advancing sustainability within supply chains. This study applies a comprehensive cradle-to-grave Life Cycle Assessment (LCA) to evaluate the environmental performance of beef destined for export, following ISO 14040, ISO 14044 and ISO 14067 standards and the Product Category Rules for meat of mammals. Sixteen impact categories were quantified for 1 kg of vacuum-packed beef using detailed primary data from a pasture-based production system and a representative processing facility. The total climate change impact was 3.27 × 10¹ kg CO₂eq, with enteric methane and feed production jointly responsible for over 70% of overall impacts. Slaughtering and distribution were associated mainly with fossil energy use and ozone depletion, while soil carbon sequestration partially compensated biogenic emissions. The results were consistent with international benchmarks, highlighting the environmental advantages of pasture-based systems, low fertilizer use, and stable land management. Key hotspots were identified in animal growth, feed efficiency, and manure management, with logistics also contributing notably. Overall, the study provides a high-resolution environmental baseline that can support Environmental Product Declarations and guide targeted mitigation strategies across beef supply chains. While the results are derived from a specific pasture-based production system, the study is positioned as a case-study-based application of a high-resolution LCA framework, illustrating how detailed inventories can support environmental benchmarking and hotspot identification without implying statistical representativeness of all beef production systems. Full article

This study investigates the potential of Fischer–Tropsch (FT) waxes, synthesized from natural gas, as high-performance and sustainable alternatives to conventional ester waxes in cosmetic applications. To evaluate their technical viability, a series of FT waxes with varying hydrocarbon chain lengths were synthesized and characterized. Safety was rigorously assessed through human patch tests and irritation surveys, while sensory attributes, including gloss and transparency, were compared against beeswax and carnauba wax. Furthermore, the impact on the skin barrier was analyzed using Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy to determine lipid packing characteristics. The results demonstrated that FT waxes possess an excellent safety profile with irritation levels comparable to traditional waxes. Sensory evaluations revealed that adjusting the hydrocarbon chain length allows for precise control over melting points and texture, offering significant formulation flexibility. Crucially, lipid packing analysis indicated that FT waxes promote an orthorhombic organization, effectively mimicking and reinforcing the native crystalline structure of the human skin barrier. These findings conclude that FT waxes provide both superior sensory properties and functional skin-barrier benefits, positioning them as versatile and innovative ingredients for advanced dermo-cosmetic formulations. Full article

The two-dimensional chiral self-assembly and chiral separation of achiral Ext-TEB molecules on a Bi(111) surface were investigated using low-temperature scanning tunneling microscopy (LT-STM). At low coverage, the molecules self-assembled into chiral clusters. As the coverage increased, a monolayer film with a non-edge-sharing honeycomb structure was formed. This supramolecular structure exhibited organizational chirality, accompanied by chiral separation. Upon annealing, part of the non-edge-sharing honeycomb structure transformed into a close-packed structure, while retaining the organizational chirality, supramolecular chirality, and pronounced chiral separation. Furthermore, applying a higher bias was found to induce a transition in the electronic state of the non-edge-sharing honeycomb structure, converting it into an edge-sharing honeycomb configuration. This study reveals that the chirality of 1,3,5-tris(4-ethynylphenyl) benzene (Ext-TEB) arises from the rotation of the side-chain phenyl rings, which is induced by the rotation of the molecular axis relative to the substrate lattice. This work presents a strategy for the preparation of chiral nanostructures from achiral molecules due to the spontaneous chiral symmetry generation. Full article

Two novel cocrystals of zwitterionic trimethylglycine (TMG) with 2,6-dichlorophenol [TMG•2,6-dichlorophenol] (1:1) and 2,6-dibromophenol [TMG•2,6-dibromophenol] (1:2) are synthesized and structurally characterized using single crystal X-ray diffraction. To estimate the energy of various intermolecular interactions, periodic DFT calculations were performed followed by Bader analysis of the crystalline electron density. TMG molecules form dimers in [TMG•2,6-dichlorophenol] (1:1). Its supramolecular structure is governed by the primary charge-assisted H-bonds (~60 kJ/mol) and supported by C–H∙∙∙O contacts (~12 kJ/mol). Cl/Br substitution introduces a more potent halogen-bonding donor. The Br∙∙∙O⁻ interaction (~10 kJ/mol) is strong enough to reorganize the packing into a catemeric motif. As a result, TMG molecules form infinite chains in [TMG•2,6-dibromophenol] (1:2). This illustrates that “fine tuning” is not merely about changing distances, but about shifting the entire energy hierarchy of the crystal. Two-dimensional fingerprint diagrams (2D diagrams) obtained from the Hirshfeld surface and Bader’s analysis of the crystalline electron density give significantly different values of the contributions of the H∙∙∙H contacts, 28% vs. 5% respectively. The main reason for this discrepancy is the large number of relatively short intermolecular H∙∙∙H contacts without a critical bond point in trimethylglycine cocrystals. Full article

Monoenoic fatty acids (MUFAs), defined by the presence of a single carbon–carbon double bond within a long aliphatic chain, constitute a structurally diverse and ecologically significant class of lipids widely distributed in aquatic organisms. In marine and freshwater environments, MUFAs are fundamental components of membrane phospholipids and storage lipids, where mono-unsaturation modulates melting point, lipid packing, and bilayer dynamics, enabling homeoviscous adaptation to fluctuations in temperature, pressure, salinity, and oxygen availability. Positional and geometric isomerism (e.g., cis-Δ5, Δ7, Δ9, Δ11, Δ13, and trans forms) further enhances biochemical diversity, providing sensitive chemotaxonomic markers and indicators of trophic transfer across food webs. In addition to common straight-chain monoenes, rare methyl-branched, cyclopropane-containing, and acetylenic derivatives occur in specialized aquatic taxa, reflecting evolutionary adaptation and ecological niche differentiation. Computational QSAR analyses suggest that monoenoic fatty acids and their unusual analogues occupy bioactivity spaces associated with lipid metabolism regulation, vascular and inflammatory modulation, antimicrobial defense, and membrane stabilization. This review integrates structural chemistry, biosynthesis, ecological distribution, trophic dynamics, and predicted biological activity of monoenoic fatty acids in aquatic systems, highlighting their dual role as adaptive membrane constituents and as biologically active mediators linking molecular lipid architecture to hydrobiological function and environmental change. Full article

We report the synthesis, spectroscopic characterization, and single-crystal X-ray structures of 5-methyl-3-phenylbenzo[e][1,2,4]triazine (I) and its precursor N′-(3-methyl-2-nitrophenyl)benzohydrazide (IV). Compound IV was obtained by nucleophilic aromatic substitution of 1-fluoro-3-methyl-2-nitrobenzene with benzohydrazide and was converted to I through a reductive cyclodehydration/oxidative aromatization sequence. The present study provides a concise route to the 5-methyl regioisomer together with full structural characterization and examines how methyl substitution at the 5-position influences molecular geometry and crystal packing relative to the previously reported 6- and 8-methyl analogs. X-ray analysis shows that IV adopts a conjugated hydrazide framework with a twisted N–N linkage and an out-of-plane nitro group. In the crystal, it forms one-dimensional N–H⋯O hydrogen-bonded chains further assembled by weaker intermolecular contacts. By contrast, I displays an essentially planar benzo[e][1,2,4]triazine core with an almost coplanar phenyl substituent and packs into slipped π-stacked columns reinforced by secondary C–H⋯N contacts. Comparison with the previously reported methyl regioisomers shows that relocation of the methyl group to the 5-position has little effect on the intrinsic molecular geometry of the benzo[e][1,2,4]triazine scaffold, while subtly modulating the stacking arrangement and secondary packing interactions in the solid state. These results further define the role of methyl-substituent position in shaping the supramolecular organization of 3-phenylbenzo[e][1,2,4]triazines. Full article

Interest in non-centrosymmetric crystalline materials exhibiting second harmonic generation (SHG) has increased due to their potential applications in optical sensing and biosensing. Saccharide-based metal complexes are particularly attractive systems, as chiral sugars can promote non-centrosymmetric crystal packing. In this work, a new lanthanum–β-d-fructose compound, [La(C₆H₁₂O₆)(H₂O)₅]Cl₃ (LaFRUCl), was synthesized using a simple and low-cost method and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ and consists of infinite (La³⁺–fructose)_n chains extending along the [001] direction, forming a one-dimensional Metal–Organic Framework. The nonlinear optical response was evaluated using the Kurtz–Perry powder technique with a Nd:YAG laser (1064 nm) and compared to a sucrose reference. The measured SHG efficiency is comparable to that of previously reported alkaline earth metal–sugar analogs. While the compound’s SHG emission is significant, evaluation of its structural stability under aqueous or physiological conditions is be required before considering biological applications. Full article

India’s rapid growth in electric vehicles and renewable energy systems is driving strong growth in lithium-ion battery demand. This study provides an India-specific life cycle assessment of manufacturing using imported primary materials with pathways incorporating domestically recycled materials. Two battery chemistries of strategic relevance to India, nickel-manganese-cobalt (NMC 532) and lithium iron phosphate (LFP), were evaluated using a functional unit of 1 kWh battery pack. The ReCiPe midpoint method was used to quantify the environmental impacts, with a focus on major emission indicators (CO₂, NO_x, SO_x, and PM₁₀) in the Indian electricity mix. The results show that NMC 532 batteries exhibit higher emissions than LFP batteries, largely due to the energy-intensive production of nickel and cobalt sulphate precursors. The incorporation of recycled materials substantially reduces emissions for both chemistries. It decreases by 30% for NMC532 and 36% for LFP. Hotspot analysis shows that precursor production, electricity use, and chemical inputs in hydrometallurgical recycling are the main causes of the remaining effects. This study shows that integrating recycling to India’s LIB supply chain improves climate and air quality outcomes, enhances critical mineral recovery and supports sustainable manufacturing through circular economy pathways for India’s battery and clean energy transition. Full article

Polymer films and polymer blend films are widely used as functional materials; however, their photophysical behavior cannot be fully explained solely by bulk properties such as relative permittivity or glass transition temperature. In this study, we investigate how local polymer microenvironments regulate fluorescence responses by employing two strongly emissive solvatochromic dyes—FπPCM, a D–π–A-type π-conjugation-extended fluorene dye, and PK, a D–π–A-type pyrene dye—as molecular probes. The photophysical properties of these dyes were systematically examined in a series of transparent polymer matrices, including polystyrene, polycarbonate, poly(methyl methacrylate), poly(vinyl chloride), triacetylcellulose, poly(butyl methacrylate), and poly(2-ethyl-2-oxazoline). Polymer films containing the dyes were prepared by solution casting from homogeneous polymer–dye solutions onto quartz substrates followed by solvent evaporation. Both dyes exhibited polymer-dependent variations in fluorescence wavelength, quantum yield, and lifetime, reflecting not only differences in polymer polarity but also local chain packing and specific dye–polymer interactions. Fluorescence lifetime analysis of PS/POz blend films revealed microscopic heterogeneity even in miscible systems, quantitatively captured using averaged lifetime parameters. Temperature-dependent fluorescence measurements further demonstrated that thermal history and structural relaxation significantly influence local polymer environments. In particular, ratiometric fluorescence analysis of PMMA/PBMA blend films enabled reproducible temperature sensing over a wide range from 30 to 120 °C, despite an overall negative temperature response. These results establish solvatochromic dyes as versatile optical probes for evaluating local polymer microenvironments and highlight their potential for polymer-state monitoring and fluorescence-based temperature-sensing applications. Full article

Microbial contamination of table eggs remains an important food safety concern, largely due to the presence of Salmonella spp. on eggshell surfaces and the potential for cross-contamination along the collection, grading, and packing chain. Conventional sanitation practices, including chlorinated-water washing, can reduce surface microbial loads but may also present limitations related to cuticle alteration, process variability, water use, and the risk of recontamination when operational conditions are not tightly controlled. This review synthesizes evidence on non-thermal and selected mild thermal technologies for the surface decontamination of intact table eggs, including ultraviolet-C (UV-C) irradiation, pulsed light, ozone-based treatments (gas and microbubble systems), non-thermal plasma, plasma-activated water, and gas-phase hydroxyl radical processes. For each approach, antimicrobial performance is discussed alongside effects on eggshell integrity, cuticle preservation, and key quality indicators (e.g., Haugh unit, albumen pH, yolk color, and shell strength). Particular attention is given to industrial constraints that influence real-world performance, such as treatment uniformity and shading effects, humidity dependence, line speed, equipment integration, and validation criteria. A shared limitation of surface treatments is their inability to inactivate pathogens that have penetrated shell membranes or contaminated egg contents, underscoring the need to align technology selection with the targeted hazard and the regulatory context. Thus, available data indicate that non-thermal technologies can contribute to reducing eggshell contamination when properly optimized, although broader implementation will depend on standardized operating parameters, robust process validation, and regulatory acceptance within existing egg processing systems. Full article

The title compound 2-iodopyridin-3-yl acetate was obtained by acetylation of the OH group of 2-iodo-3-hydroxypyridine. Knowing that the hydroxyl group, as a strong H-bond donor in halogenated hydroxypyridines, usually directs supramolecular packing and might enforce possible halogen–halogen contacts, we crystallized 2-iodo-3-acetoxypyridine with the aim of disrupting the most important H-bond donor and assessing the propensity of the iodine for halogen bond formation. Indeed, in the compound 2-iodopyridin-3-yl acetate, the crystal packing is characterized by infinite 3D chains bonded through I···O=C and C-H···I contacts between adjacent molecules. These chains are interconnected by weak C-H···O contacts, implying the presence of oxygen in the ester. The I···H contact with the C-H axis perpendicular to the electron belt of the iodine atom can enhance the σ-hole of the iodine and act cooperatively in crystal cohesion. No halogen–halogen contacts were present. Full article

Designing the high-performance polyimides (PIs) for the biomimetic structures, which are used in extreme conditions, remains greatly challenging, due to the conflict between processability and thermal stability. Here, we report a series of silicon–alkyne-functionalized diamine-based polyimides that exhibit remarkable processability and thermal stability. The incorporation of bulky siloxy groups disrupts chain packing and increases free volume, enabling excellent solubility in polar solvents, while the rigid fluorene core enhances chain stiffness. DFT calculations confirm twisted molecular geometries (Si bond angle ≈ 103°, dihedral angle ≈ 89°) which weak π–π stacking, while heterogeneous electrostatic potentials enable favorable noncovalent interactions (e.g., C–F···H–C), promoting solvent diffusion. After thermal curing, the obtained product shows a high decomposition temperature (T_d5% = 560 °C), char yield of 72.0% at 800 °C, and glass transition temperature (T_g) of 354.6 °C. Meanwhile, locally planar fluorene units retain inherent thermal stabilization benefits through constrained rotational mobility. These results demonstrate a spatially decoupled siloxy–alkyne design that synergistically enhances molecular flexibility, disorder, and electronic stability, offering a molecular strategy for tailoring PI-based matrices to meet the demands of emerging biomimetic architectures and other high-performance composites operating under severe thermal loads. Full article