Search Results (1,743)

Recently, research and development in the field of dye-sensitized solar cells has been actively advanced, as the technology constitutes a potential alternative to silicon-based photovoltaic devices. Modification of the molecular structure of the dye can enhance the adsorption on the TiO₂ surface, improve the light absorption capacity, suppress the charge recombination, increase the electron injection rate, and thereby improve the overall performance of the solar cell. Carbazole and phenothiazine are rigid heterocyclic compounds containing nitrogen as a heteroatom with large π-conjugated skeletons. Phenothiazine differs from carbazole by the presence of sulfur as an additional electron-rich heteroatom. The inclusion of this heteroatom in the structure of the compounds can indeed improve the electron-donating properties, affect the conjugation, and thus affect the optical, electronic, and electrochemical properties of the chromophores as a whole. The difference in planarity when comparing carbazole with phenothiazine can be useful from several points of view. The planar structure of carbazole increases the degree of conjugation and the electron transfer capacity, which can increase the photocurrent of the cell. The nonplanar structure of phenothiazine helps to prevent π-stacking aggregation. This review comprehensively summarizes the progress in the field of synthesis of organic dyes for solar cells with an emphasis on the comparative analysis of two electron-donating moieties, carbazole and phenothiazine. In addition, the review describes in detail the relationship between the structure of the compounds (dyes), their properties, and the performance of solar cells. Full article

This study investigated strontium (Sr²⁺) adsorption by Taiwan Zhi-Shin bentonite (cation exchange capacity (CEC): 80–86 meq 100 g⁻¹) using Sr(NO₃)₂-simulated nuclear waste. Kinetic analysis revealed pseudo-second-order adsorption kinetics, achieving 95% Sr²⁺ removal within 5 min at pH 9. Isothermal studies showed a maximum capacity of 0.28 mmol g⁻¹ (56 meq 100 g⁻¹) at 15 mmol L⁻¹ Sr²⁺, accounting for 65–70% CEC and fitting the Freundlich model. Cation exchange was the dominant mechanism (84% contribution), driven by Sr²⁺ displacing interlayer Ca²⁺. Alkaline conditions (pH > 9) enhanced adsorption through improved surface charge and electrostatic attraction. Thermodynamic studies demonstrated temperature-dependent behavior: increasing temperature reduced adsorption at 0.01 mM Sr²⁺ but increased efficiency at 10 mM. Na⁺ addition suppressed adsorption, aligning with cation exchange mechanisms. Molecular dynamics simulations identified hydrated Ca²⁺-Sr²⁺ water bridges interacting with bentonite via hydrogen-bonding networks. The material exhibits rapid kinetics (5 min equilibrium), alkaline pH optimization, and resistance to ion interference, making it suitable for emergency Sr²⁺ treatment. It shows promise as a cost-effective and good performing adsorbent for radioactive waste solutions. Full article

Apricot kernel shells were evaluated as a sustainable activated carbon precursor for wastewater treatment using experimental and theoretical methods. Two adsorbents were synthesized: physically activated with CO₂ (AKS-CO₂) and chemically activated with H₃PO₄ (AKS-H₃PO₄). Comprehensive materials characterization and adsorption tests using Pb²⁺ ions and Rhodamine B dye (RhB) as model pollutants revealed that AKS-H₃PO₄ significantly outperformed its physically activated counterpart. With an exceptionally high specific surface area (1159.4 m²/g) enriched with phosphorus-containing functional groups, the chemically activated carbon demonstrated outstanding removal efficiencies of 85.1% for Pb²⁺ and 80.3% for RhB. Kinetic studies showed Pb²⁺ adsorption followed pseudo-second-order kinetics, indicating chemisorption, while RhB adsorption fitted pseudo-first-order kinetics, suggesting intra-particle diffusion control. The thermodynamic analysis confirmed the spontaneity of both processes: Pb²⁺ adsorption was exothermic under standard conditions with positive isosteric heat at higher concentrations, reinforcing its chemisorption nature, whereas RhB adsorption was endothermic, consistent with physisorption. Density Functional Theory (DFT) calculations further elucidated the mechanisms, revealing that Pb²⁺ preferentially binds to oxygen-containing functional groups, while RhB interacts through hydrogen bonding and π–π stacking. These findings establish chemically activated apricot kernel shell carbon as a high-performance adsorbent, exhibiting exceptional removal capacity for both ionic and molecular contaminants through distinct adsorption mechanisms. Full article

SnSe₂, as a prominent member of the post-transition metal dichalcogenides, exhibits many intriguing physical phenomena and excellent thermoelectric properties, calling for both fundamental study and potential application in two-dimensional (2D) devices. In this article, we realized the molecular beam epitaxial growth of SnSe₂ films on a $\sqrt{3}\times \sqrt{3}$-Sn reconstructed Si(111) surface. The analysis of reflection high-energy electron diffraction reveals the in-plane lattice orientation as SnSe₂[110]//$\sqrt{3}$-Sn [112]//Si [110]. In addition, the flat morphology of SnSe₂ film was identified by scanning tunneling microscopy (STM), implying the relatively strong adsorption effect of $\sqrt{3}$-Sn/Si(111) substrate to the SnSe₂ adsorbates. Subsequently, the interfacial charge transfer was observed by X-ray photoemission spectroscopy. Afterwards, the direct characterization of electronic structures was obtained via angle-resolved photoemission spectroscopy. In addition to proving the presence of interfacial charge transfer again, a new relatively flat in-gap band was found in monolayer and few-layer SnSe₂, which disappeared in multi-layer SnSe₂. The interface strain-induced partial structural phase transition of thin SnSe₂ films is presumed to be the reason. Our results provide important information on the characterization and effective modulation of electronic structures of SnSe₂ grown on $\sqrt{3}$-Sn/Si(111), paving the way for the further study and application of SnSe₂ in 2D electronic devices. Full article

In chemical vapor deposition (CVD)-mediated graphene growth, copper foil serves as both a catalyst for methane decomposition and as a substrate for graphene nucleation and growth. Due to the low solubility of carbon in copper and the ease of transferring graphene from its surface, copper—particularly the Cu(111) facet—is widely favored for high-quality, monolayer graphene synthesis. In this article, the thermodynamic processes involved in methane dissociation and graphene nucleation on the Cu(111) surface were investigated using density functional theory (DFT). Molecular dynamics simulations were performed for structural optimization and to evaluate the reaction energies. Additionally, the average adsorption energies (ΔEad) of carbon clusters with varying atomic numbers on the Cu(111) surface were calculated. The graphene growth process was further modeled using the kinetic Monte Carlo (KMC) method to simulate carbon atom migration and nucleation dynamics. Thermodynamic analysis based on equilibrium component data was conducted to examine the influence of key operational parameters—temperature, pressure, and the CH₄/H₂ partial pressure ratio—on the graphene deposition rate. Full article

The electrocatalytic CO₂ reduction reaction (CO₂RR) into value-added multi-carbon C₂₊ products holds significant promise for sustainable chemical synthesis and carbon-neutral energy cycles. Among the various strategies developed to enhance CO₂RR, the use of ionic liquids (ILs) has emerged as a powerful approach for modulating the local microenvironment and electronic structure of Cu-based metal catalysts. In this study, to unravel the molecular-level mechanisms underlying these enhancements, density functional theory calculations (DFTs) were employed to systematically explore how ILs with different terminal groups modulate the electronic reconstruction of the Cu surface, further affecting the *CO–*CO coupling and product selectivity. Electronic structure analyses reveal that ILs bearing polar moieties (–SH, –COOH) can synergistically enhance the interfacial electron accumulation and induce an upshift of the Cu d-band center, thereby strengthening *CO adsorption. In contrast, nonpolar IL (CH₃) exhibits negligible effects, underscoring the pivotal role of ILs’ polarity in catalyst surface-state engineering. The free energy diagrams and transition state analyses reveal that ILs with polar groups significantly lower both the reaction-free energy and activation barrier associated with the *CO–*CO coupling step. This energetic favorability selectively inhibits the C₁ product pathways and hydrogen evolution reaction (HER), further improving the selectivity of C₂ products. These theoretical insights not only unveil the mechanistic origins of IL-induced performance enhancement but also offer predictive guidance for the rational design of advanced IL–catalyst systems for efficient CO₂ electroreduction. Full article

The objective of this study is to investigate the molecular regulatory mechanisms of non-coding RNA (ncRNA) during the developmental process of multi-litter sheep ovaries and identify key regulatory genes that enhance the reproductive capacity of sheep. This study selected Small-Tail Han sheep (multi-litter sheep) and Ujumuqin sheep (single-litter sheep) as comparative models, constructed the expression profiles of ncRNAs and mRNAs in ovarian tissues, identified differentially expressed (DE) lncRNAs, circRNAs, miRNAs, and mRNAs, and performed target gene prediction along with functional and signaling pathway enrichment analyses. Reproduction-related pathways were further screened to construct competing endogenous RNA (ceRNA) regulatory networks (lncRNA–miRNA–mRNA and circRNA–miRNA–mRNA). Finally, the dual-luciferase reporter gene assay system was employed to perform the functional validation of the relevant targeted regulatory effects. A comprehensive screening identified 411 DE lncRNAs, 322 DE circRNAs, 26 DE miRNAs, and 29 DEGs from the ovarian tissues of Ujumqin and Small-Tail Han sheep. The results of the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses demonstrated that the DE target genes were significantly enriched in pathways associated with cell dedifferentiation, the positive regulation of embryonic development, glycosaminoglycan biosynthesis, Hippo signaling, and other signaling pathways. To identify genes associated with reproductive processes, we performed differential expression screening followed by pathway enrichment analysis, which revealed significant enrichment in reproductive regulatory pathways. Based on these findings, we constructed a ceRNA regulatory network incorporating 22 DEGs, 17 DE lncRNAs, three DE circRNAs, and one DE miRNA. Our analysis revealed that oar-let-7a is involved in signaling pathways such as oocyte meiosis and Hippo, suggesting it may serve as a key miRNA regulating the trait of multiple offspring. The dual-luciferase reporter assay was employed to confirm that oar-let-7a directly targets and regulates the expression of CPEB1. Additionally, it was demonstrated that circRNA803 and lncRNA MSTRG.19726 function as molecular sponges to competitively bind and regulate oar-let-7a. These findings suggest that oar-let-7a mediates the expression of CPEB1 via circRNA803 and lncRNA MSTRG.19726 sponge adsorption, thereby regulating the process of follicular dominance in sheep. The qRT-PCR method was employed to validate the expression patterns of nine randomly selected DEGs, and the results corroborated the reliability of the RNA-seq sequencing data. This study investigated the coordinated regulatory mechanism of DE ncRNAs and their corresponding target genes, identifying a ceRNA network, circRNA803/lncRNA MSTRG.19726-oar-let-7a-CPEB1, which plays a critical role in regulating the process of follicular dominance in sheep. These findings provide fundamental data for uncovering the reproductive potential of sheep and facilitate a comprehensive understanding of their reproductive characteristics, which hold significant guiding implications for enhancing reproductive efficiency. Full article

Poly(3,3-bis(azidomethyl)oxetane(BAMO)-tetrahydrofuran(THF)) copolymer (PBT) and ammonium perchlorate (AP) are critical components of solid rocket propellants, where their interfacial bonding mechanisms and temperature-dependent mechanical properties are pivotal to propellant reliability. In this study, density functional theory (DFT) calculations were employed to evaluate the adsorption energies between common AP crystal surfaces and PBT units, identifying the most energetically favorable adsorption configurations. The atomic configurations and charge transfer characteristics at the PBT-AP interface were systematically analyzed. Molecular dynamics (MD) simulations were further conducted to determine the thermally stable operating range of the PBT-AP system. The results reveal a strong temperature dependence of mechanical performance, with viscous failure mechanisms and damage thresholds during static tensile processes investigated across varying temperatures. Notably, mechanical properties remain stable below 60 °C but deteriorate significantly above this temperature. This study elucidates the influence of a PBT-AP interfacial microstructure and temperature on mechanical performance and tensile fracture damage boundaries, providing crucial insights for the design, formulation, and safe application of PBT-based solid rocket propellants. Full article

By introducing the concept of nanoreaction-based fluctuating mixing entropy, the challenge posed by the smallness of a closed molecular system is addressed through equilibrium statistical–mechanical averaging over fluctuating reaction extent. Based on the canonical partition function, the interplay between the mixing entropy and fluctuations in the reaction extent in nanoscale environments is unraveled while maintaining consistency with macroscopic behavior. The nanosystem size dependence of the mixing entropy, the reaction extent, and a concept termed the “reaction extent entropy” are modeled for the combination reactions $A+B\leftrightarrow 2C$ and the specific case of $H_2+I_2\leftrightarrow 2HI$. A distinct inverse correlation is found between the first two properties, revealing consistency with the nanoconfinement entropic effect on chemical equilibrium (NCECE). To obtain the time dependence of the instantaneous mixing entropy following equilibration, the Stochastic Simulation (Gillespie) Algorithm is employed. In particular, the smallest nanosystems exhibit a step-like behavior that deviates significantly from the smooth mean values and is associated with the discrete probability distribution of the reaction extent. As illustrated further for molecular adsorption and spin polarization, the current approach can be extended beyond nanoreactions to other confined systems with a limited number of species. Full article

This study investigates the synergistic enhancement of molecular oxygen activation (MOA) in silver phosphate (Ag₃PO₄) photocatalysts modified with oxygen vacancies (OVs) and silver nanoparticles (Ag⁰). The vacuum-calcined Ag₃PO₄ exhibited a 2.05-fold increase in the degradation efficiency of cylindrospermopsin (CYN), reaching 88.00% within 5 min, compared to its pristine counterpart. This work proposes a novel dual-modification approach—rarely explored in previous MOA studies—by introducing OVs and Ag⁰ simultaneously. The characterization results confirmed that OVs improved the charge transfer and adsorption of molecular oxygen, while the Ag⁰ nanoparticles facilitated electron–hole separation and interfacial charge transfer. Reactive oxygen species (ROS) such as ·O₂⁻, ¹O₂, H₂O₂, and ·OH were confirmed via ESR analysis and chemical assays. A detailed mechanism was proposed and illustrated, showing how OVs and Ag⁰ synergistically promote MOA. These findings highlight a cost-effective method for enhancing photocatalysis and environmental remediation. Full article

The rapid isolation of target constituents from natural products poses a significant challenge and is a key focus in current research. The Hosta plantaginea flower (HPF), a traditional Chinese medicinal herb, is primarily used to treat inflammatory diseases, with kaempferol as one of its major bioactive constituents. In this study, macroporous adsorption resin was used to purify total flavonoids (TF) from the HPFs. The 50% ethanol–water elution fraction of the TF was then recrystallized to yield kaempferol with a purity of 99.44%. Network pharmacology analysis identified 61 potential kaempferol-inflammation targets, which were linked to the PI3K-Akt and TNF signaling pathways. Molecular docking and molecular dynamics simulations revealed the stability and binding of kaempferol to PI3K, Akt, and TNF-α proteins. The analysis metrics included binding ability, the root mean square deviation (RMSD), radius of gyration, free energy landscape, solvent-accessible surface area, hydrogen bond count, RMS fluctuation, free binding energy, amino acid residue free energy decomposition, and principal component analysis. The anti-inflammatory mechanism of kaempferol was further validated in an LPS-induced RAW264.7 cell model, where it was shown to inhibit the PI3K-Akt and TNF-α signaling pathways. This study provides new insights into the anti-inflammatory mechanism of kaempferol and presents novel strategies for the rapid isolation of target constituents from natural products. Full article

Wastewater-based molecular epidemiology enables the surveillance of both symptomatic and asymptomatic individuals in a non-invasive, cost-effective, rapid, and early-detection manner. The use of wastewater analysis to monitor the prevalence of viral pathogens in a given population has increased significantly since the COVID-19 pandemic. These studies typically involve three main steps: viral concentration, nucleic acid extraction, and DNA/RNA quantification. However, the absence of a standardized methodology remains a major limitation, hindering result comparability across studies. Among the available viral concentration techniques, aluminum-based adsorption–precipitation is one of the most commonly used due to its simplicity, efficiency, and low cost. This study evaluates the robustness and variability of the viral concentration and nucleic acid extraction steps by implementing different process controls in wastewater samples across 122 independent experiments. Additionally, correlations between viral recovery efficiencies and relevant physicochemical parameters were also analyzed (n = 600). The results indicate that, despite the overall robustness of the method, the concentration step exhibits the highest variability (CV = 53.82%), which accounted for 53.73% of the overall variability. In addition, our results show that, on average, 0.65 logarithmic units were lost during the viral concentration step. Furthermore, viral recovery rates were influenced by seasonality and sample characteristics, while no significant correlation was observed with pH or conductivity. These findings highlight the importance of process controls, confirming the robustness of the methodology, and identifying key parameters that should be considered in future studies for improved data interpretation. Full article

Investigating the adsorption properties of emulsifiers at water–oil interfaces enables advances in the comprehension of the mechanisms governing emulsion ageing and stabilization. The utilization of natural compounds in emulsion formulations is increasingly relevant for those applications where it is challenging to maintain a low impact on the environment and health. We report here a study on saponin and chitosan at the interface between water and medium-chain triglycerides (MCT) oil in relation to the properties of the corresponding emulsions. Complementary experimental approaches have been adopted to investigate interfacial properties and emulsion evolution, relying on drop tensiometry, optical and confocal microscopy, and light transmission/scattering analysis. In addition, molecular dynamics simulation has been undertaken as support for the interpretation of the experimental results. The multi-technique investigation adopted here enabled a better understanding of saponin adsorption properties and of the role of chitosan in emulsion evolution. In particular, the results evidence the formation of amphiphilic saponin–chitosan complexes, which adsorb at the liquid–liquid interface and improve the stability of oil-in-water emulsions. Since the system investigated mainly consists of natural compounds, the results of this work can contribute to the development of new and efficient low-impact formulations. Full article

Surfactants are often used in the process of coal dust suppression, and the wetting effect is greatly affected by the surfactant hydrophilic group structures. In order to explore the influence of hydrophilic groups of surfactants on their adsorption states and wetting effect on coal dust, three surfactants with similar hydrophilic groups were selected, namely, anionic surfactant sodium dodecyl sulfate (SDS), anionic-nonionic surfactant alkyl ether sulfate (AES), and nonionic surfactant alkyl polyoxyethylene ether-3 (AEO-3). To assess surfactant efficiency, surface tension, wetting time, infrared spectra, and wetting heat were analyzed. These parameters provide insights into molecular adsorption, interfacial behavior, and energy changes during wetting. The different adsorption states of surfactants on the coal dust surface due to EO and SO₄²⁻ hydrophilic groups were analyzed. Results show that both anionic surfactant SDS and nonionic surfactant AEO-3 form the monolayer adsorption structure on the coal dust surface. Due to the electrostatic repulsion of SO₄²⁻ groups, the adsorption density of SDS is lower than that of AEO-3, which results in the higher wetting heat of AEO-3 compared to SDS. In addition, the EO groups without electrostatic repulsion make AEO-3 molecules more tightly adsorbed at the air–liquid interface, causing the minimal surface tension. Therefore, the wetting time of AEO-3 is shorter than that of SDS. The anionic-nonionic surfactant AES has both EO and SO₄²⁻ groups. Because the EO groups in the inner surfactant adsorption layer can attract Na⁺ ions to distribute around them, the free AES molecules further form the outer adsorption layer under the electrostatic attraction between SO₄²⁻ groups and Na⁺ ions. The double-layer adsorption structure causes the hydrophobic groups of the outer AES molecules to face outward, the hydrophobic sites on the coal dust surface are not completely transformed into hydrophilic sites. Although AES exhibits the highest adsorption density, it has the lowest wetting heat and the longest wetting time. The research results can provide theoretical guidance for the selection of suitable surfactants for coal dust suppression. Full article

The present study aims to prepare a composite via pyrolysis, based on sodium alginate (SA) and a natural clay collected from the eastern region of Morocco, specifically the OUJDA area (C.O.R), for use in the disposal process of emerging pharmaceuticals. The strategy of rapid microwave heating followed by nitrogen calcination at 500 °C was successfully applied to produce the pyrolyzed carbonaceous materials. The removal of paracetamol (PCT) by adsorption on the carbonaceous clay (ca-C.O.R) composite was investigated to determine the effect of operating parameters (initial contaminant concentration, contact time, pH, and temperature) on the efficiency of PCT removal. The nanocomposite was analyzed using various techniques, including the nitrogen gas adsorption–desorption isothermal curve, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Three models were used to describe the kinetic adsorption, and it was found that the experimental kinetic data fit well with a pseudo-second-order kinetic model with a coefficient of determination R² close to one, a nonlinear chi-square value close to zero, and a reduced root mean square error RMSE (R² → 1, X² → 0 and lower RMSE). The adsorption was best described by the Sips isotherm. The ca-C.O.R composite achieved a PCT removal efficiency of 91% and a maximum adsorption capacity of 122 mg·g⁻¹ improving on the performance of previous work. Furthermore, the variation in enthalpy (∆H°), Gibbs free energy (∆G°), and entropy (∆S°) indicated that the adsorption is exothermic in nature. The composite has shown promising efficiency for the adsorption of PCT as a model of emergent pollutant from aqueous solutions, making it a viable option for industrial wastewater treatment. Using Density Functional Theory (DFT) along with the 6-31G (d) basis set, the geometric structure of the molecule was determined, and the properties were estimated by analyzing its boundary molecular orbitals. The adsorption energy of PCT on MMT and ca-C.O.R studied using the Monte Carlo (MC) simulation method was −120.3 and −292.5 (kcal·mol⁻¹), respectively, which shows the potential of the two adsorbents for the emerging product. Full article