Frontiers in Chemistry最新文献

The current study, employing density functional theory, reports the hydrogenation of acetone to isopropyl alcohol catalyzed by CAl₃MgH₂ ^¯, which contains a planar tetracoordinate carbon (ptC). Various computational approaches are employed to analyze acetone hydrogenation using the CAl₃MgH₂ ^¯ as a potential catalyst. The reaction initiates with the carbonyl insertion into the Mg-H bond of the CAl₃MgH₂ ^¯, followed by hydrogenation using molecular hydrogen (H₂). Analysis of natural atomic charges confirms that the H₂ molecule dissociates heterolytically into a proton-hydride pair, thereby regenerating the CAl₃MgH₂ ^¯ in the product state. Intrinsic reaction coordinate calculations confirm the true connection between the reactant and product in the reaction pathway. This investigation highlights the potential of the ptC molecule as a catalyst and delineates the way for new opportunities in ptC-based catalysts.

Cancer remains one of the major public health problems due to its high morbidity and mortality globally. Because metastasis is the major cause of cancer death, developing new approaches for early diagnosis is of paramount importance in this context. Surface-enhanced Raman scattering (SERS) has emerged as a cutting-edge analytical technique. SERS features an exceptional sensitivity and specificity, enabling rapid non-destructive detection of trace-level samples. Therefore, SERS technology is widely used across medical disciplines, particularly in cancer diagnosis for early-stage and non-invasive diagnostic evaluation. Using liquid biopsy with rich metabolic information, SERS has facilitated the identification, analysis, and progression monitoring of various cancers. In this review, we systematically summarize recent advances in label-free SERS-based cancer diagnostics. We first outline the fundamental principles of SERS, key substrate fabrication methodologies, and essential spectral analysis techniques. We then highlight the applications of label-free SERS in liquid biopsy using various biofluids, including blood, urine, saliva, and sweat. Finally, we discuss current challenges and future directions in this rapidly evolving field.

Medicinal plants constitute the primary pharmacological source of Chinese medicine and their scientific interpretation is crucial for quality standardization and clinical guidance. Paradoxically, the contemporary evaluation model primarily adopts reductionism, inconsistent with the system-oriented holistic view of Traditional Chinese Medicine (TCM). In this review, the commonality between the organismic electromagnetic radiation field and the "qi" of TCM was deeply dissected from five levels. This reveals the fundamental consistency between the biophoton coherence and the holism of TCM. The scientific connotation of Chinese medicinal properties may be the ability and metric to regulate quantum superposition states of biological electromagnetic fields. Therefore, employing biophoton emission (BE)-based methods to investigate the medicinal properties of medicinal plants may provide scientific support that aligns more closely with holism. BE technology has shown great potential in quantifying medicinal characteristic parameters, including the quantization of Chinese medicinal properties, the identification of various processed products, and quality control. Especially in the real-time quality monitoring during the cultivation process of medicinal plants, BE characteristics can comprehensively reflect the natural and efficacious properties. This interdisciplinary thinking will help to establish a novel theoretical framework and methodological system to advance the modernization and development of medicinal plants.

The valorization of glycerol, a large-volume byproduct of biodiesel production, remains a key challenge for the biorefinery sector. Among the available strategies, its acetalization with acetone offers a sustainable route to produce solketal, a valuable fuel additive. The feasibility of this valorization route is, however, largely dependent on the continuous research towards highly performant, stable catalysts with carefully designed acidic sites. In this work, hybrid porous zirconium phosphonate-phosphate materials were synthesized and evaluated as recyclable heterogeneous catalysts. The acidity was systematically investigated using Hammett indicators, supported by solid-state ³¹P NMR, XPS, and ammonia TPD analyses. Their structural and thermal stability was also assessed. The incorporation of phosphate groups was found to be essential to provide sufficient Brønsted acidity and enhance the long-term stability of the catalysts, as evidenced by their successful recyclability during multiple catalytic runs. In addition, yields of 85%, with a selectivity of 98% can be reported in optimal conditions, and the catalyst was even found to offer very promising conversions at room temperature.

Introduction: This study focuses on the detection mechanisms of recently developed NIR fluorescent probes that depend on ring formation and opening processes. A novel class of polymethine dyes (NIRII-RTs) serves as the core fluorescent moiety of these probes, which exhibit bright, stable, and anti-solvent quenching NIR-II emission, accompanied by large Stokes shifts.

Methods: Quantum chemical calculation methods were employed to systematically analyze the light absorption and emission processes of three target-specific probes: NIR-pH (targeting H⁺), NIR-ATP (targeting ATP), and NIR-Hg (targeting Hg²⁺).

Results: The results demonstrated that the probes exhibit weak fluorescence in the closed spiro cyclization state. This weak emission is attributed to the interrupted π-electron distribution at the C-N bond of the reaction site, which facilitates electron transfer from the ground state to the excited state and restricts excitation to the benzene ring region. Upon reaction with target analytes, the spiro cyclization structure is disrupted, transitioning to a linear chain configuration.

Discussion: The consistency between the calculated optical parameters and experimental data validates the proposed detection mechanism centered on spiro cyclization/ring-opening processes and associated changes in π-electron conjugation. This mechanism clarifies how the structural flexibility of the probes (driven by analyte binding) regulates their fluorescence properties, providing a theoretical basis for the rational design of high-performance NIR-II fluorescent probes with tunable optical responses. Future work may leverage this mechanism to develop probes for a broader range of analytes, further advancing their utility in biological imaging and environmental monitoring.

[This corrects the article DOI: 10.3389/fchem.2023.1273360.].

The performance of asphalt concrete under increasing traffic loads and varying climatic conditions necessitates the development of enhanced bituminous binders. Some additives used as asphalt modifiers are polymeric materials. Examples of these polymers are styrene-butadiene rubber latex (SBR), diblock styrene-butadiene (SB) and triblock styrene-butadiene-styrene (SBS). The use of crumb rubber from worn-out tires can be considered as polymer-modified bitumen. This study investigates the effects of ethylene-vinyl acetate (EVA) granules and crumb rubber waste as modifiers on the physical, mechanical, and chemical properties of asphalt concrete. An ever-increasing pressure on waste resources and environmental protection leads to clear transition to a regenerative circular economy. The research aims to address the limitations of conventional bitumen, such as thermal instability and susceptibility to aging, particularly in regions with high traffic loads and extreme temperatures, by incorporating these polymer additives at 20% and 25% dosages relative to the binder mass. Laboratory-prepared asphalt concrete mixtures were evaluated for key performance indicators, including compressive strength at 0, 20 °C and 50 °C, water saturation, moisture resistance, crack resistance, shear stability, and rutting depth. Results demonstrated that EVA granules significantly improved thermal stability, with crack resistance at 0 °C doubling from 3.0 to 6.9 MPa. Compressive strength also increased to 2.2 MPa compared to the control sample (0.9 MPa). Rutting resistance was notably enhanced, with EVA-modified mixtures exhibiting an 85% reduction in rut depth (0.77 mm) compared to the unmodified mix (4.9 mm). Crumb rubber, while less effective in thermal performance, improved water resistance by reducing water saturation from 2.7% to 2.4% and demonstrated moderate gains in deformation resistance. Fourier-transform infrared spectroscopy (FTIR) revealed distinct chemical interactions between the modifiers and bitumen. EVA introduced polar functional groups (e.g., C=O at 1738 cm^-1 and C-O-C at 1,242 cm^-1), indicating chemical integration, whereas crumb rubber primarily influenced physical structure, evidenced by polyisoprene-related bands (966-970 cm^-1). Economic analysis highlighted that EVA would be more cost-effective, due to lower material costs and superior performance. Both modifiers support sustainability by repurposing industrial waste. It turned out that both modifiers can contribute to environmental sustainability by repurposing industrial waste.

Quantum computing holds promise for molecular similarity analysis in chemoinformatics and drug discovery. We propose a quantum circuit to encode the classically pre-computed Tanimoto similarity (T), obtained from extended-connectivity fingerprints (ECFPs) with RDKit, into a compact three-qubit entangled state using Qiskit. A 3-qubit circuit with RY rotations encodes T coefficients, while CNOT gates create an entangled three-qubit state that serves as a sensitive probe for quantum noise and error-mitigation performance. Simulations under noise demonstrate that exponential mitigation reduces errors by 75.0% for similar pairs (e.g., aspirin-aspirin) and 87.5% for dissimilar pairs (e.g., aspirin-butane) at a 1% error rate, maintaining fidelity within ±0.001 deviation. At 10% depolarization noise, error reduction drops to 25.0% and 17.4% for these pairs, respectively. The overall results show that the mitigation is proportionally more effective for low-similarity pairs. Experiments on IBM Quantum hardware confirm Z-basis reliability but reveal challenges with X-basis noise. Our work demonstrates quantum-encoded T representation and recovery on NISQ devices as a proof-of-concept, highlighting the critical role of error mitigation in hybrid quantum-classical workflows.

Background: Angiogenesis is a fundamental physiological process mediating vascular network formation, represents a critical therapeutic target for ischemic diseases and tumor neovascularization. Xuefu Zhuyu decoction (XFZYD), a classical formula for promoting blood circulation and resolving stasis, demonstrates pro-angiogenic effect with safflower functioning as the sovereign herb. Hydroxysafflor yellow A (HSYA), the primary bioactive constituent of safflower, exerts potent angiogenesis modulation, defining its pharmacological significance.

Methods: In this study, in vitro tubulogenesis assay and cytocompatibility analysis were employ on human microvascular endothelial cell (HMEC-1), followed by target prediction via network pharmacology and molecular docking; immunoblotting analysis was performed to experimentally validate the pro-angiogenic molecular mechanism of HSYA.

Results: HSYA exerted concentration-dependent pro-angiogenic effects on HMEC-1 cells over 24 h without compromising cell viability (p > 0.05) across 0-200 μM. 121 potential targets of HSYA within the angiogenesis regulatory network were identified. Functional enrichment analysis revealed fluid shear stress, lipid metabolism, HIF-1, PI3K-Akt, and VEGF signal pathways as primary regulatory pathways. 8 hub targets derived from the protein-protein interaction (PPI) network were subjected to molecular docking. High-affinity interactions were observed for key angiogenesis regulators: MMP9 (-7.6 kcal·mol^-1), and HIF-1α(-4.5 kcal·mol^-1), which were functionally validated by immunoblotting analysis, preliminary demonstrating the mechanism of HSYA-mediated angiogenesis promotion.

Conclusion: HSYA demonstrates significant pro-angiogenic activity on HMEC-1. Mechanistically, HSYA modulates multiple signaling pathways, with HIF-lα and MMP9 demonstrating regulatory significance. These findings suggest a molecular basis for HSYA's therapeutic potential in ischemic vascular pathologies.

Tomato pomace is an abundant by-product of the agri-food industry with a peel rich in cutin, a plant polyester that can be depolymerized to monomeric building blocks to develop bio-based materials. Because of cutin's crosslinked, three-dimensional structure, alkaline hydrolysis has typically required long reaction times (up to 24 h) to achieve complete depolymerization into its monomers, which hinders the potential development of exploitation processes. In this paper, the effect of temperature and heating mechanism (conventional versus microwave-assisted hydrolysis) on monomer production yield and final product composition of the hydrolysis process were studied. The comparison of the two methods was also based on a detailed kinetic analysis of the hydrolysis processes. The results showed that the usage of microwaves at 120 °C allowed to reduce the reaction time from 24 h at 100 °C to only 1 h, with no significant differences to the conventional hydrolysis method in terms of monomeric composition, but with higher yields. This reduction in processing time promotes the development of new applications from the corresponding monomers and facilitates cutin characterization for analytical purposes.