Search Results (800)

This study evaluates the effects of hydrogen enrichment of compressed natural gas (HCNG, CNG) on particle number emissions and particle size distribution in a dual-fuel compression-ignition (CI) engine. The experiments were conducted using a Fiat 1.3 MultiJet engine operated with conventional diesel fuel, diesel–CNG, and diesel–hydrogen-enriched CNG. Measurements were performed over a range of engine speeds, loads, and energy-substitution conditions. The hydrogen volume fraction in the gaseous fuel ranged from 5–10 vol.% to 53 vol.%. Particle size distributions were measured using an ELPI+ impactor. The use of CNG and hydrogen generally reduced soot-particle emissions in the accumulation mode, particularly within the particle-diameter range of approximately 0.03–0.2 µm. However, under some operating conditions, the number of ultrafine particles increased, particularly in the sub-23 nm range. This finding indicates a transition from a particle-formation mechanism dominated by soot formation and agglomeration to one dominated by nucleation and condensation. This phenomenon is associated with suppressed soot-precursor formation, enhanced soot oxidation by OH radicals, and a reduction in the surface area available for the condensation of volatile components. The effect of hydrogen depended on the engine operating point (EOP) and did not always scale linearly with hydrogen concentration. The results confirm that evaluating alternative fuels solely on the basis of particulate mass is insufficient. Particle number, particle size distribution, and the sub-23 nm fraction must also be considered. Full article

Epilobium parviflorum Schreb. is a medicinal plant used traditionally against inflammatory disorders whose cytotoxic potential is still incompletely revealed. The current study investigates the phytochemical composition and in vitro cytotoxic activity of four hydroalcoholic extracts prepared from the aerial parts of E. parviflorum by using maceration and Soxhlet extraction. The extracts were characterized in terms of total phenolic, flavonoid and tannins composition and LC-MS was used to identify its individual polyphenols. Their biological effects were assessed against four cancer cell lines (A375 melanoma, HT-29 colorectal adenocarcinoma, PANC-1 pancreatic carcinoma and SK-OV-3 ovarian adenocarcinoma cells), while using HaCaT keratinocytes as healthy cells in order to assess selectivity. Cell viability, cytoskeletal and nuclear morphology, mitochondrial respiration and network pharmacology were further investigated. A complex phenolic profile was revealed, with hyperoside being identified as the main component in all extracts while the extraction parameters strongly influenced the recovery of various phenolic compounds. All extracts reduced cancer cell viability in a dose-dependent manner after 24 h exposure, with the most pronounced effects observed at 720 and 1000 μg/mL, while HaCaT cells were left relatively unaffected. The morphological assessment indicated nuclear condensation, fragmentation and cytoskeletal disruption following the application of extracts. Moreover, high-resolution respirometry showed reduced oxidative phosphorylation and electron transfer system capacity thus indicating that early mitochondrial dysfunction may contribute to the cytotoxic effects. Network pharmacology revealed that ERBB2, CTNNB1, HSP90AA1 and HDAC6 might act as molecular targets in melanoma. Thus, these findings support the hypothesis that E. parviflorum hydroalcoholic extracts, particularly the 40% ethanol Soxhlet extract, may serve as important sources of bioactive phytocompounds with antiproliferative and apoptotic properties. Full article

Novel and efficient total syntheses of the nonsteroidal anti-inflammatory drugs Pelubiprofen and Loxoprofen via a photo-Favorskii rearrangement are reported herein. The key photochemical transformation was optimized under both batch and continuous-flow conditions using a suitably functionalized chloro-phenylpropan-1-one derivative, affording the target 2-arylpropionic acid in excellent yield. Implementation under continuous-flow conditions increased process productivity and enabled gram-scale operation. Aerobic oxidation of the benzylic position to the corresponding aldehyde, followed by Claisen–Schmidt condensation with cyclohexanone, afforded Pelubiprofen in 35% overall yield. Alternatively, condensation with cyclopentanone afforded the corresponding α,β-unsaturated enone intermediate, whose selective reduction under flow conditions enabled access to Loxoprofen in 28% overall yield. The versatility of the methodology was further demonstrated through the synthesis of Carprofen, highlighting the broader applicability of the photo-Favorskii rearrangement to the synthesis of APIs through previously unreported synthetic routes. Full article

Hydrogen sulfide (H₂S), a high-volume by-product of the hydrodesulfurization of fossil fuels, can be valorized by thermolysis to recover both molecular hydrogen and elemental sulfur, rather than being oxidized as in the conventional Claus process. The viability of this route depends on quantitative knowledge of the reaction mechanism and of the energy costs of dissociation, which are difficult to obtain experimentally at the temperatures involved. Here we study H₂S thermolysis by reactive molecular dynamics (RMD) with the ReaxFF potential for systems of 1000 H₂S molecules at 1 atm, addressing three coupled questions: the simulation parameters required for dilute gases, the energetics of dissociation, and the elementary reaction mechanism. The interaction cutoff radius proved critical: the original 10 Å value, parametrized for condensed systems, misses about 23 eV of attractive non-bonded interaction energy in the gaseous system at 298.15 K (≈0.023 eV per molecule) and fails to capture dissociation at 3000 K within 20 ns, whereas radii of 30–40 Å converge. Using a 40 Å cutoff at 2500, 3000 and 3500 K, atom-resolved species-transition records reveal a free-radical chain mechanism built from the same set of elementary steps at the three temperatures, whose relative contributions shift with temperature: S–H homolysis initiates the chain, hydrogen abstraction (H• + H₂S → H₂ + HS•) is essentially the exclusive source of H₂ (persistent H• + H• recombination contributed only 1, 13 and 17 events, below 0.5% of the abstraction count), and a slow sulfur-condensation stage (S₂ → S₃ → S₄) limits the net conversion, which reached 9.3 ± 0.9%, 26.3 ± 1.4% and 46.7 ± 1.6% within the simulated windows (single-trajectory counting resolution)—kinetically limited values, not equilibrium conversions. The enthalpy of the system rises linearly with the number of H₂S molecules consumed (R² ≥ 0.99), defining energy costs of 2.46 ± 0.04, 3.10 ± 0.08 and 3.95 ± 0.18 eV per molecule that increase with temperature by ≈1.48 eV per 1000 K; at 3500 K the cost lies between the 0 K complete-dissociation limit D₀ = 3.90 eV derived from the experimental H–SH bond energy and the Kirchhoff-corrected complete-dissociation enthalpy at that temperature (4.11–4.12 eV), statistically indistinguishable from the latter (a 0.9σ difference). These results provide a thermochemically validated, molecular-level basis for engineering the valorization of residual H₂S as a source of green hydrogen. Full article

Cryopreservation of ovine semen is associated with oxidative stress and structural sperm damage, which may compromise post-thaw sperm quality. Natural antioxidants derived from agro-industrial by-products have emerged as potential alternatives to reduce cryo-induced damage. The present study evaluated the effect of lyophilized coffee grounds extract (LCGE) supplementation on sperm quality during refrigeration and cryopreservation of Dorper and Creole ram semen. Semen samples from ten rams (five per breed) were allocated to three treatments based on LCGE concentration: 0 mg/mL (control), 1.0 mg/mL, and 1.5 mg/mL. Cryopreservation significantly affected all CASA-derived sperm parameters, with breed-dependent responses detected for several kinetic traits. LCGE supplementation had limited effects on CASA-derived sperm motility and kinetic parameters, with a significant dose effect detected only for total motility. In contrast, higher plasma membrane functionality, acrosomal integrity, DNA integrity, and chromatin condensation were observed in cryopreserved semen supplemented with LCGE, particularly at 1.5 mg/mL. LCGE-treated samples also exhibited a lower occurrence of moderate and high oxidative stress categories than cryopreserved control samples. Overall, the findings indicate that LCGE supplementation was associated with higher plasma membrane functionality, acrosomal integrity, DNA integrity, and chromatin condensation in cryopreserved semen. Further studies are required to determine the biological mechanisms involved and to evaluate the effects of LCGE supplementation on fertility under in vivo conditions. Full article

The traditional precursor-derived ceramic (PDC) route uses micron-sized titanium sources and silicon carbide precursors to prepare Ti₃SiC₂, which limits its application in fine-scale fields. We propose a fully liquid Ti-Si-C-O precursor, consisting of tetrabutyl titanate (TBT) and liquid polycarbosilane (LPCS), inspired by the carbothermal reduction of solid oxides to prepare Ti₃SiC₂. The fully liquid precursor can offer processing advantages that are not achievable through previous PDC processes. The pyrolysis of the TSO-1 (TBT:LPCS = 3:2) undergoes four stages: dehydration condensation (RT~200 °C), alkoxy removal (200~400 °C), inorganic conversion (400~800 °C), and carbothermal reduction (>800 °C). The products of TSO-1 pyrolyzed to 1400 °C and 1600 °C are Ti₃O₅, SiO₂ and TiC, and Ti₃O₅, Ti₂O₃, SiO₂ and TiC, respectively. Increasing the LPCS content in the system can promote the formation of TiC, but will not produce Ti₃SiC₂. This phenomenon stems from the dual constraints: thermodynamically, titanium oxides outcompete SiO₂ for carbon; kinetically, the gaseous escape of effective carbon and its microscale non-uniform distribution further impair the carbothermal reduction of SiO₂. These combined factors prevent the gas–solid reaction from establishing, rendering Ti₃SiC₂ unattainable. Full article

Triple-negative breast cancer (TNBC) remains a highly aggressive malignancy with limited therapeutic options and frequent resistance to platinum-based chemotherapy. Rosmarinic acid (RA), a naturally occurring polyphenol, has attracted considerable interest as a potential chemosensitising agent. This study investigated the anticancer activity and the underlying mechanisms of RA combined with cisplatin (CDDP) in 4T1 breast cancer cells while assessing the cytotoxic responses of non-cancerous HaCaT keratinocytes as a preliminary indicator of differential treatment sensitivity. Cytotoxicity was assessed using the MTT assay, followed by calculation of the Combination Index (CI), Drug Reduction Index (DRI), and Selectivity Index (SI). The generation of intracellular reactive oxygen species (ROS) was evaluated by DCFH-DA fluorescence imaging, and the functional contribution of oxidative stress was examined using N-acetyl-L-cysteine (NAC) rescue experiments. Apoptosis was analysed by Annexin V/PI flow cytometry, NucBlue nuclear staining, and Calcein-AM/propidium iodide (PI) Live/Dead fluorescence imaging. Three-dimensional (3D) tumour spheroids were used to assess treatment-induced alterations in spheroid morphology, morphometric parameters, viability based on adenosine triphosphate (ATP), and Live/Dead staining. The expression of genes related to apoptosis was determined by RT-qPCR, and potential molecular mechanisms were explored using the construction of protein–protein interaction (PPI) networks together with Gene Ontology (GO) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analyses. The combination of RA + CDDP exhibited strong synergistic cytotoxicity in 4T1 cells while demonstrating comparatively lower toxicity toward HaCaT keratinocytes. Combination treatment markedly increased intracellular ROS generation, whereas NAC significantly reduced ROS accumulation and partially restored cell viability, indicating that oxidative stress is a major but not exclusive mediator of cytotoxicity. Combined treatment significantly enhanced apoptotic cell death, increased chromatin condensation and membrane damage, upregulated the expression of Bax, Casp9, Cycs, and Trp53, and downregulated Bcl2, consistent with transcriptional regulation of intrinsic apoptotic signalling. In 3D tumour spheroids, the combination markedly reduced spheroid size, disrupted structural integrity, decreased ATP-based viability, and substantially increased tumour cell death compared to monotherapy. Bioinformatic analyses identified central genes related to apoptosis and cell survival and predicted significant enrichment of PI3K/Akt, p53, MAPK, and apoptosis signalling pathways. RA significantly potentiates the antitumor efficacy of CDDP through synergistic induction of ROS-associated apoptotic signalling while showing a more favourable cytotoxic response in 4T1 breast cancer cells than in non-cancerous HaCaT keratinocytes. The integrated findings from two-dimensional (2D) and 3D models, NAC rescue experiments, molecular analyses, and bioinformatics collectively support the potential of RA as a promising chemosensitising adjuvant for CDDP-based breast cancer therapy and warrant further validation in preclinical in vivo models. Full article

Simple phenolic compounds can act as antioxidants or prooxidants depending on their structure and environmental conditions. Glutamate-induced excitotoxicity leads to neurodegeneration, astrocyte dysfunction, oxidative stress, and neuroinflammation. This study examined six phenolics: catechol, phloroglucinol, resorcinol, pyrogallol, hydroquinone, and hydroxyquinol, assessing their effects on astrocyte survival in a glutamate-excitotoxic model. Mouse astrocytes (C8-D1A) were exposed to 20 mM glutamate, with phenolics added before, during, or after treatment. Cell viability, morphology, nuclear condensation, ROS levels, and inflammatory cytokines were measured using the MTT assay, microscopy, CellROX, and RT-qPCR. Simultaneously, treatment improved astrocyte survival and preserved morphology, whereas pre- or post-treatment did not confer protection and worsened toxicity at higher doses. Resorcinol showed the strongest protective effect, followed by hydroxyquinol and hydroquinone at lower doses. Resorcinol and hydroxyquinol decreased ROS levels, whereas pyrogallol and hydroquinone increased cell survival without reducing ROS. All four lowered IL-6 and TNF-α. These findings demonstrate that the effects of phenolics, whether protective or toxic, depend on concentration, structure, and timing, underscoring their dual role in excitotoxic environments. They also identify resorcinol as a promising candidate for further preclinical study. Full article

Two alternative first-stage routes for selective molybdenum recovery from a pretreated spent Co-Mo/Al₂O₃ hydrodesulfurization catalyst were investigated and compared using the same feedstock: direct sulfuric-acid leaching and oxidative volatilization. The study combined single-factor process tests with XRD, SEM-EDS, XRF, ICP-OES, and particle-size analyses to relate extraction behavior to the distribution of Mo and Co within the catalyst. Direct leaching achieved 98.1% Mo extraction in 2 mol/L H₂SO₄ at 90 °C for 2 h, while approximately 95% extraction was obtained at only 0.1 mol/L H₂SO₄ and 40 °C. Co co-extraction remained at approximately 12%, and Al extraction was generally 0.6–0.9%, demonstrating a selective first-stage separation. Water leaching provided an extraction of 51.3% Mo because readily accessible MoO₃ forms hydrated aqueous Mo(VI) species. Oxidative roasting removed 92.2% Mo from the coarsely ground material at 1400 °C for 1 h, while fine grinding increased Mo volatilization to 97.8%, whereas no measurable Co volatilization was observed. The two routes therefore offer different advantages: mild leaching lowers thermal demand and produces a Mo-bearing solution, whereas roasting avoids liquid reagents and produces a Mo-bearing vapor that can be collected by controlled condensation. The residual Mo fraction was associated with MoO₂ and Mo-bearing regions enclosed by the stable CoAl₂O₄-Al₂O₃ matrix. The results establish a comparative basis for selecting an appropriate first-stage Mo-removal route before separate recovery of Co and possible valorization of the alumina-rich residue. Full article

Solar stills are considered an effective solution to produce fresh drinking water from saline water. Solar stills utilize solar energy, which is available in abundant quantity for long periods across Middle Eastern countries like Oman. In this study, two single-slope passive solar stills are fabricated with two configurations: a Conventional Solar Still (CSS) and a Modified Solar Still (MSS). The CSS is the basic model, whereas the MSS is a model obtained by incorporating copper tubes that are filled with phase change material (PCM) combined with nano copper oxide particles, which are attached inside the basin. The objective of this study is to compare the performance of the two systems from energy, exergy, and economical aspects. The solar stills were fabricated according to the geometrical conditions of the city Nizwa, Oman, and the standards for the fabrication of each solar still component. The highlights of this research are comparing the performance of the CSS and MSS under the prevailing atmospheric conditions of the city Nizwa, Oman, and investigating the effects of the nano materials and phase change materials used in the MSS on its performance. The results of the study reveal certain important facts; for example, higher thermal conductivity of the copper tubes increases the heat transfer and evaporation of saline water inside the basin. The freshwater production in the MSS was higher than in the CSS, with an average difference of about 79.75%. This difference in freshwater production is due to the accumulated heat storage and release of heat from the PCM material combined with nanoparticles during reduced solar radiation. The nanoparticles contributed to an increase in the heat transfer rate of the PCM. The presence of copper tubes filled with nano-PCM in the MSS influences and increases both energy and exergy efficiencies to around 30 to 35% and 1 to 1.5% compared to those in the CSS. The increased efficiencies in the MSS are due to its improved evaporation and condensation rates, which enhance the energy utilization in the process of converting saline water to freshwater. Full article

A tetraphenylethylene-based salen-type Schiff base ligand and its Fe(III) coordination complex were synthesized and characterized using spectroscopic, electrochemical, mass spectrometric, and single-crystal X-ray diffraction techniques. The ligand features an N₂O₂ donor set and was obtained via Schiff base condensation with ethylenediamine, while reaction with FeCl₃ afforded a di-μ-phenoxo-bridged dinuclear Fe(III) complex under mild conditions. Unlike previously reported Fe(III)-salen electrochromic systems, which are predominantly mononuclear and exhibit ligand-centered redox processes with limited modulation of intraligand electronic communication, the present system incorporates a rigid tetraphenylethylene scaffold and forms a centrosymmetric di-μ-phenoxo-bridged Fe(III) dimer. This structural motif enables coordination-induced electronic coupling between phenolate units, resulting in a distinct splitting of ligand-centered oxidation processes. Single-crystal X-ray diffraction confirmed a di-μ-phenoxo-bridged Fe(III) dimer with distorted octahedral geometry. Electrochemical studies show a quasi-reversible ligand-centered oxidation in the free ligand, which splits into two separate redox events upon complexation, indicating the emergence of electronically non-equivalent redox sites. Spectroelectrochemical analysis reveals the formation of phenoxyl radical species accompanied by ligand-centered intervalence charge–transfer transitions and the appearance of a near-infrared absorption band upon oxidation. A reversible color change from red to blue is observed, reflecting redox-driven modulation of the electronic structure. Overall, this work demonstrates that incorporation of a tetraphenylethylene-based salen framework and formation of a di-μ-phenoxo-bridged Fe(III) dimer enables coordination-triggered intraligand electronic communication, leading to fundamentally different redox behavior compared to previously reported Fe(III)-salen electrochromic complexes, while no reversible metal-centered redox processes were detected within the experimentally investigated potential window. Full article

To address the issues of complicated procedures and high costs associated with the conventional two-step synthesis of 2-ethyl-2-hexenal (2E2H), this paper develops a novel route for the one-step synthesis of this high-value intermediate via the tandem hydroformylation–aldol condensation of propylene. A series of supported Rh-based bifunctional catalysts were prepared using metal oxides as supports, and the catalytic performance of different supports in the tandem system was systematically investigated. Through TEM, SEM, XRD, and XPS characterizations, combined with DFT calculations, the polarization and activation mechanism of the C=O bond of n-butyraldehyde by TiO₂ was elucidated. Under optimized conditions (90 °C, 4 MPa, 6 h), the as-prepared Rh/TiO₂ catalyst achieved a propylene conversion of 49.2%, a total butyraldehyde selectivity of 75.8%, and 2-ethyl-2-hexenal selectivity of 24.2%. Furthermore, the catalyst exhibited good recycling stability and could be reused for five cycles without significant loss of activity. This work provides an effective strategy for the value-added upgrading of propylene resources and the design of tandem catalytic systems. Full article

Olive leaves, a major byproduct of olive processing, are generated in large quantities annually yet suffer from inefficient utilization and low added value. In this study, response surface methodology (RSM) was employed to optimize the extraction conditions of oleuropein from olive leaves. Additionally, the antioxidant activity of purified oleuropein and its protective effect against tret-butyl hydroperoxide (TBHP)-induced oxidative damage in the human embryonic kidney 293 (HEK-293) cell line were investigated. The optimal extraction conditions for oleuropein were determined as follows: extraction temperature of 71 °C, extraction time of 72 min, ethanol concentration of 58%, and solid–liquid ratio of 1:27 (mg/mL), yielding an oleuropein recovery of 44.5%. The extract was purified and identified as oleuropein via Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). Oleuropein exhibited remarkable antioxidant activity and mitigated TBHP-induced oxidative damage in HEK-293 cells by inhibiting apoptosis. TBHP treatment reduced cell viability by approximately 70%, while treatment with 100 and 200 μg/mL oleuropein restored the decreased cell viability to 100%. Morphological observations and 4′,6-diamidino-2-phenylindole (DAPI) staining revealed that TBHP induced apoptotic cell death characterized by nuclear condensation and fragmentation, and this effect was reversed by oleuropein treatment. Flow cytometry analysis showed that TBHP caused approximately 90% cell death, whereas co-treatment with oleuropein reduced cell death to only about 10%. TBHP downregulated the expression of p53, and oleuropein reactivated its expression, highlighting the role of oleuropein in the recovery of the cellular antioxidant system. This study possibly indicated the protective mechanism of oleuropein against oxidative damage-related diseases and provides a theoretical basis for the development of olive leaves as a potential ingredient in functional foods. Full article

A new benzimidazole–6β-acetoxyvouacapane (4aS,5R,6aS,7R,11aS,11bR)-9-(1-benzyl-1H-benzo[d]imidazol-2-yl)-4,4,7,11b-tetramethyl-1,2,3,4,4a,5,6,6a,7,11,11a,11b-dodecahydrophenanthro[3,2-b]furan-5-yl acetate was synthesized through the semisynthetic functionalization of the natural product 6β-acetoxyvouacapane. The target compound was obtained via a liquid-assisted mechanochemical condensation of aldehyde 6β-acetoxyvouacapane with N-benzyl-o-phenylenediamine, followed by cyclization and oxidative aromatization under mild reaction conditions. The structure of the new compound was established by FT-IR, 1D and 2D NMR spectroscopy (COSY, HSQC, and HMBC), and high-resolution mass spectrometry (HRMS). Full article

The development of bio-based adhesives has emerged as a viable strategy to reduce fossil-derived resin consumption in wood and wood-based panel applications. This review provides a polymer-focused assessment of adhesive systems derived from proteins, carbohydrates, lignin, and tannins, emphasizing molecular architecture, crosslinking chemistry, interfacial interactions, and structure–property relationships. Adhesive performance is primarily dictated by functional group density, crosslinking efficiency, and network topology. Protein-based adhesives rely on hydrogen bonding and covalent crosslinking with lignocellulosic substrates but require structural modification to improve hydrothermal stability. Carbohydrate-based systems, including starch and cellulose derivatives, offer reactive hydroxyl functionalities that enable oxidation, esterification, and etherification pathways for enhanced network formation. Lignin and tannins, characterized by phenolic and aromatic structures, facilitate condensation reactions and enable partial substitution of phenol in thermosetting resins, supporting low-formaldehyde or formaldehyde-free formulations. Hybrid polymer networks, particularly protein–carbohydrate and lignin-modified systems, demonstrate improved crosslink density, reduced hydrophilicity, and enhanced mechanical performance. Life cycle analyses indicate that increasing biogenic carbon content and minimizing fossil-based cross-linkers can lower global warming potential (GWP) and volatile organic compound (VOC) emissions. Overall, a structure–property–sustainability framework is proposed to guide molecular design and performance optimization of next-generation bio-based wood adhesives. Full article