Frontiers in Chemistry最新文献

Background: Siloxanes have been widely used in various products and have been detected to varying degrees in the environment. It has been reported that methylsiloxane has toxic effects on the nervous, immune and reproductive systems of aquatic animals, and is carcinogenic and mutagenic. Therefore, in order to protect human health, it is urgent to establish a method for the determination of siloxane content in drinking water and source water.

Methods: Herein, this paper proposes a precise, fast, and selective method using solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS/MS) method for the simultaneous detection of 11 kinds of siloxanes in drinking water and source water. Quantification of siloxanes was carried out by internal standard method. The parameters that affect the extraction and desorption processes were optmised. The extraction efficiency of four commercially available SPME fibers was evaluated. The results showed that divinylbenzene/polydimethyl-siloxane or divinylbenzene/Carboxen/polydimethylsiloxane was the best coating for the extraction of siloxane.

Results: This method provided good linearity (r > 0.9946) and precision (RSD% <8.0%) with the minimum detection mass concentration ranging from 0.008 to 0.025 μg/L under the optimized extraction and GC-MS/MS analysis conditions. The developed method has been applied to the simultaneous analysis of 11 kinds of siloxanes in drinking water and source water, and the results showed that decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) were found in two source water samples at concentrations ranging from 0.008 to 0.012 μg/L and 0.015-0.019 μg/L, respectively.

Conclusion: This developed method was simple, quick, and effective and our satisfactory results demonstrated its suitability for the simultaneous determination of 11 kinds of siloxanes in drinking water and source water.

In the present study, a library of ten novel substituted 1,3,4-thiadiazole derivatives were designed and synthesized using an appropriate synthetic route. The characterization of the synthesized compounds was performed by FT-IR and NMR (¹H and ¹³C) spectroscopy. The synthesized compounds were assayed for in vitro human carbonic anhydrase (CA) inhibition against two isoforms II and IX. The neurotoxicity of the synthesized derivatives was also evaluated using the rotarod test, along with their in vivo anticonvulsant activity, which was determined using the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (sc-PTZ) methods. Although all the compounds showed good CA inhibition and anticonvulsant activity, two compounds 6d and 7d showed the highest CA inhibition and anticonvulsant activity in both the isoforms and tested methods compared to the standard drugs (sodium valproate and acetazolamide), without any sign of neurotoxicity observed at the highest dose (300 mg/kg). Similarly, the standard drugs also displayed no neurotoxicity at the highest dose (300 mg/kg). Furthermore, the potent compounds (6d and 7d) were evaluated for the biochemical parameters, such as lipid peroxidation, nitrite oxide, reduced glutathione, superoxide dismutase, and total antioxidant capacity, and the GABA level was also determined. Finally, compound 6d was docked against CA-II and CA-IX (PDB-ID-5SZ5 and 5AML) receptors. The study concluded that the compounds 6d and 7d can be considered potent anticonvulsant agents for future research.

Hydrogen is a promising candidate for renewable energy storage and transportation due to its high energy density and zero carbon emissions. Its practical applications face challenges related to safe, efficient storage and release systems. This review article investigates advanced nanostructured materials for hydrogen storage, including metal acetylide and cyanide complexes, B,N-doped γ-graphyne nanotubes (γ-GNT), lithium-phosphide double helices, and Ni-decorated carbon-based clusters. Density Functional Theory (DFT) based computations are used to analyze binding energies, thermodynamic stability, and adsorption mechanisms. Ni-decorated C₁₂N₁₂ nanoclusters demonstrate enhanced storage capacities, binding up to eight H₂ molecules with a favorable N-(μ-Ni)-N configuration. Lithium-phosphide double helices show potential for 9.6 wt% hydrogen storage within a stable, semiconducting framework. Functionalization of γ-GNT with OLi₂ at boron-doped sites significantly enhances storage potential, achieving optimal hydrogen binding energies for practical applications. Additionally, metal acetylide and cyanide complexes, stabilized by noble gas insertion, display thermodynamically favorable hydrogen adsorption. These results highlight the potential of these functionalized nanostructures for achieving high-capacity, reversible hydrogen storage. The nanostructures in this study, such as γ-graphyne nanotubes (γ-GNT), lithium-phosphide double helices, metal acetylide and cyanide complexes, and Ni-decorated carbon-based clusters, are selected based on their ability to exhibit complementary hydrogen adsorption mechanisms, including physisorption and chemisorption. γ-GNT offers high surface area and tunable electronic properties, ideal for physisorption enhanced by heteroatom doping. Lithium-phosphide double helices facilitate Kubas-like chemisorption through unsaturated lithium centers. Metal acetylide and cyanide complexes stabilize hydrogen adsorption via charge transfer and conjugated frameworks, while Ni-decorated clusters combine polarization-induced physisorption. These materials represent a strategic approach to addressing the challenges of hydrogen storage through diverse and synergistic mechanisms. The review also addresses challenges and outlines future directions to advance hydrogen's role as a sustainable fuel.

Nanoparticles show superior potential for enhancing thermal properties compared to conventional particle-liquid suspensions. This investigation delves into magnetohydrodynamics (MHD) drift, heat, and mass transfer effects within a Jeffery nanoparticle liquid. The study includes transference equations that consider the influences of thermophoresis and Brownian motion on particle deposition. The analysis examines the impact of a nanofluid through a porous, exponentially elongating sheet, focusing on the double-stratification effects on heat and mass transference. The primary emphasis is on the formulated thermal energy equation, which incorporates Joule heating, heat generation, and ohmic dissipation terms. The initial step involves transforming the non-linear primary equations and their related boundary conditions into non-dimensional forms using similarity variables. The homotopy analysis method is then applied to obtain analytical results for the equations. Graphical representations of the impacts of various parameters on velocity and temperature values are presented, along with a detailed discussion of these impacts. A comprehensive analysis of specific parameters on the drag force factor-reduced Nusselt number and Sherwood number is provided and illustrated. Additionally, this research is applicable in environmental engineering, particularly in managing thermal pollution in water bodies, by aiding in predicting temperature distribution and the mixing behavior of effluents.

In recent years, medical micro-/nanorobots (MNRs) have emerged as a promising technology for diagnosing and treating malignant tumors. MNRs enable precise, targeted actions at the cellular level, addressing several limitations of conventional cancer diagnosis and treatment, such as insufficient early diagnosis, nonspecific drug delivery, and chemoresistance. This review provides an in-depth discussion of the propulsion mechanisms of MNRs, including chemical fuels, external fields (light, ultrasound, magnetism), biological propulsion, and hybrid methods, highlighting their respective advantages and limitations. Additionally, we discuss novel approaches for tumor diagnosis, precision surgery, and drug delivery, emphasizing their potential clinical applications. Despite significant advancements, challenges such as biocompatibility, propulsion efficiency, and clinical translation persist. This review examines the current state of MNR applications and outlines future directions for their development, with the aim of enhancing their diagnostic and therapeutic efficacy and facilitating their integration into clinical practice.

Amomi fructus (AF) has been used for both medicinal and food purposes for centuries. However, issues such as source mixing, substandard quality, and product adulteration often affect its efficacy. This study used E-nose (EN) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) to determine and analyze the volatile organic compounds (VOCs) in AF and its counterfeit products. A total of 111 VOCs were detected by HS-GC-IMS, with 101 tentatively identified. Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) identified 47 VOCs as differential markers for distinguishing authentic AF from counterfeits (VIP value >1 and P < 0.05). Based on the E-nose sensor response value and the peak volumes of the 111 VOCs, the unguided Principal Component Analysis (PCA), guided Principal Component Analysis-Discriminant Analysis (PCA-DA), and Partial Least Squares-Discriminant Analysis (PLS-DA) models were established to differentiate AF by authenticity, origin, and provenance. The authenticity identification model achieved 100.00% accuracy after PCA analysis, while the origin identification model and the provenance identification model were 95.65% (HS-GC-IMS: PLS-DA) and 98.18% (HS-GC-IMS: PCA-DA/PLS-DA), respectively. Further data-level fusion of E-nose and HS-GC-IMS significantly improved the accuracy of the origin identification model to 97.96% (PLS-DA), outperforming single-source data modeling. In conclusion, the intelligent data fusion algorithm based on E-nose and HS-GC-IMS data effectively identifies the authenticity, origin, and provenance of AF, providing a rapid and accurate method for quality evaluation.

In the Pu'er tea market, the ubiquity of blending different varieties and the fraudulent representation of vintage years present a persistent challenge. Traditional sensory evaluation and experience are often inadequate for discerning the true variety and vintage of tea, highlighting the need for more sophisticated analytical methods to ensure authenticity and quality. Fourier transform near infrared diffuse reflectance spectroscopy combined with radial basis function neural network (RBFNN) was applied for determination of the varieties and vintages of Pu'er tea. For vintage identification, the accuracy, precision, recall, and F1-score of the RBFNN model for the prediction set were 99.2%, 98.2%, 98.0%, and 98.0%, respectively. For identification of varieties adulteration, the corresponding parameters were 98.9%, 97.2%, 96.7%, and 96.6%, respectively. These results illustrated the feasibility to identify the adulteration of varieties and misrepresentation of vintages of Pu'er tea with near infrared spectra and RBFNN model, proving an efficient alternative for Pu'er tea quality inspection, and offering a robust method for combating the pervasive issues within the market.

Multiple sclerosis (MS) is a chronic autoimmune illness characterized by demyelination, neurodegeneration, and inflammation in the central nervous system. The AXL gene, which codes for a receptor tyrosine kinase, has emerged as a promising therapeutic target due to its involvement in neuroinflammation and oligodendrocyte dysfunction. In the current study, we employed in silico techniques to design Antisense Oligonucleotides (ASOs) that selectively target AXL gene transcripts to modulate AXL expression and mitigate MS pathology. Three ASOs, A1, A2, and A3, were designed to specifically target the 5' untranslated region (5'UTR) and coding region of the AXL gene transcripts. The ASOs were optimized with a focus on stability, binding affinity, and specificity towards AXL mRNA while minimizing off-target effects. To investigate ASO-mRNA interactions and gauge their ability to alter AXL expression, Molecular Docking was performed. Our analyses showed that A1, A2, and A3 had substantial interactions with AXL mRNA, with binding affinities of -9.5 kcal/mol, -10.8 kcal/mol, and -10.6 kcal/mol, respectively. The targeting of AXL gene transcripts through ASOs shows promise in reducing MS symptoms. Precision ASO-based therapies could effectively manage MS by targeting the essential pathways involved in the disease. ASOs provide a highly targeted approach for treating MS and offer a precise therapeutic strategy for this debilitating condition. The study lays the groundwork for future in vitro and in vivo studies to confirm the therapeutic potential of these ASOs for the treatment of MS.

Introduction: This study investigated the antioxidant, antimicrobial, and insecticidal properties of Chamaemelum nobile (L.) essential oil (CN-EO), harvested in Taounate, Morocco. The molecular composition and chemical profile of CN-EO were also characterized.

Methods: The CN-EO was extracted using a Clevenger apparatus. Its chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS). Antioxidant activity was evaluated using the DPPH assay, while antimicrobial properties were assessed via the disk diffusion method to measure inhibition zones against various bacterial and fungal strains. Insecticidal activity was tested through bioassays to determine insect mortality and repellency rates. Phylogenetic analysis of DNA sequences was conducted to confirm the species identity.

Results: GC-MS analysis identified 24 compounds in CN-EO, with β-Oplopenone (18.66%), Spathulenol (14.90%), and Himachalene (12.47%) as major constituents. CN-EO exhibited strong antioxidant activity (IC₅₀ = 135.8 ± 1.03 μg/mL). Antimicrobial assays revealed inhibition zones of up to 20.67 ± 0.58 mm (Staphylococcus aureus) and antifungal inhibition of 40.42% ± 2.82% against Aspergillus flavus. Insecticidal tests showed total insect mortality at 166 µL/L within 48 h and a 60% repellent effect. Phylogenetic analysis of the DNA sequence revealed a 99.22% similarity with Chamaemelum nobile (L.).

Conclusion: These results demonstrate the significant potential of Moroccan CN-EO in phytomedicine. It exhibits a wide range of biological activities and shows great promise as a natural antioxidant, antimicrobial agent, antifungal, and insecticide.