Search Results (57,617)

The kinetics of anthracene hydrogenation was studied using the method of equilibrium kinetic analysis. To determine the diffusion–kinetic characteristics, anthracene hydrogenation was performed at different temperatures (648 K, 673 K, 698 K), at a hydrogen pressure of 3 MPa in the presence of a mixture of pyrite (FeS₂) and aluminum oxide (Al₂O₃) taken at a ratio of 1:1. Chromatographic analysis of anthracene hydrogenation products showed the presence of 9,10-dihydroanthracene (DHA), 1,2,3,4-tetrahydroanthracene (THA), methylnaphthalene (MN), naphthalene (H) and other unidentified compounds. In order to preserve the material balance, a total hydrogenation reaction of anthracene, up to 9,10-dihydroanthracene, was proposed as characterized by the highest rate in the presence of pyrite-based catalysts and aluminum oxide. Calculations of the degrees of rotation of anthracene, reaction constants, and Gibbs energy have shown that with increasing temperature, the reaction becomes more thermodynamically advantageous. Based on the obtained data, Arrhenius dependences were constructed, which made it possible to calculate the activation energies of direct (39.4 kJ/mol) and reverse (13.04 kJ/mol) reactions. Thus, based on the calculations performed, it was found that the process of anthracene hydrogenation in the presence of a mixture of pyrite and aluminum oxide proceeds mainly in the diffusion region. Full article

Rosehip is of notable scientific interest due to its rich content of bioactives and its wide-ranging applications in nutrition, cosmetics and pharmaceuticals. The valorization of rosehip by-products, such as pomace, is highly significant for promoting sustainability. This study investigates the development of rosehip-based powders and beverage prototypes derived from both juice and pomace to evaluate the potential use of pomace in instant beverage design and compare it with juice-based formulations. Three matrices were evaluated: non-pasteurized and pasteurized juice, as well as non-pasteurized pomace preparations. Powders were produced by freeze- and spray drying using maltodextrin, inulin and unconventional carriers, i.e., palatinose and trehalose. The results demonstrated that carrier addition significantly influenced the physical and techno-functional properties of the powders, such as moisture content (below 10%), water activity (below 0.35), solubility (above 85%), and color indexes (yellowness and browning). The water absorption capacity varied with drying techniques, particularly for inulin-enriched samples, while the matrix type affected the ascorbic acid content. Non-pasteurized pomace powders exhibited a higher antioxidant capacity (67.7 mmol Trolox/100 g dry matter) than their juice counterparts (52.2 mmol Trolox/100 g dry matter), highlighting the potential of the pomace matrix for beverage production. Because of their favorable properties, spray-dried samples were also selected for reconstitution into prototype beverages, among which those obtained from pomace showed a higher antioxidant potential. An analysis of particle sizes, which ranged between 34 nm and 7363 nm, revealed potential interactions between the carrier and matrix, reflected in the distinct behavior of carrier-only samples. Both the carrier type and the matrix significantly contributed to the final properties of the beverages, providing valuable insights for the design of functional food products. Full article

Background: The detection of explosives in crime scene investigations is critical for forensic science. This study explores the application of laser desorption (LD) ion mobility spectrometry (IMS) as a novel method for this purpose utilising a new IMS prototype developed by MaSaTECH. Methods: The LD sampling technique employs a laser diode module to vaporise explosive traces on surfaces, allowing immediate analysis by IMS without sample preparation. Chemometric approaches, including multivariate data analysis, were utilised for data processing and interpretation, including pre-processing of raw IMS plasmagrams and various pattern recognition techniques, such as linear discriminant analysis (LDA) and support vector machines (SVMs). Results: The IMS prototype was validated through experiments with pure explosives (TNT, RDX, PETN) and explosive products (SEMTEX 1A, C4) on different materials. The study found that the pre-processing method significantly impacts classification accuracy, with the PCA-LDA model demonstrating the best performance for real-world applications. Conclusions: The LD-IMS prototype, coupled with effective chemometric techniques, presents a promising methodology for the detection of explosives in forensic investigations, enhancing the reliability of field applications. Full article

Bisphenols may negatively impact human health. In this study, we propose the use of HPLC–FLD for the simultaneous determination of bisphenols in pericardial fluid samples collected from patients with coronary artery disease undergoing coronary artery bypass surgery. For sample preparation, a fast, simple, and ”green” DLLME method was used, achieving mean recovery values in the range of 62%–98% with relative standard deviations between 2% and 6% for all analytes. Quantitative analysis of bisphenols in the samples was then performed by LC–MS/MS on a triple quadrupole (QqQ) mass spectrometer and electrospray ionization (ESI-/ESI+) was applied in the negative and positive ion modes, respectively. The LODs and LOQs ranged from 0.04 ng/mL to 0.37 ng/mL and 0.12 ng/mL to 1.11 ng/mL, respectively. Pericardial fluid was collected from patients with coronary artery disease during coronary artery bypass surgery. Bisphenol residues were identified and quantified in samples from 19 patients. The procedure was successfully applied to the biomonitoring of free forms of 14 bisphenols in pericardial fluid. After statistical examination of the relationships between the selected variables, a strongly positive correlation was found between creatinine kinase and troponin I, as well as the number of venous anastomoses, circulation time, and clamp cap time. Full article

Melanoma is among the most abundant malignancies in the US and worldwide. Ligstroside aglycone (LA) is a rare extra-virgin olive oil-derived monophenolic secoiridoid with diverse bioactivities. LA dose–response screening at the NCI 60 cancer cells panel identified the high sensitivity of the Malme-3M cell line, which harbors a BRAF V600E mutation. Daily oral 10 mg/kg LA exhibited potent in vivo antitumor effects against Malme-3M cells xenograft in a nude mouse model by targeting the BRAF signaling pathway. A human Clariom S microarray analysis of the collected Malme- 3M tumors identified 571 dysregulated genes, with the downregulation of pathways critical for melanoma cells growth and survival. A Western blot analysis of the collected animal tumors further validated the downregulation of the mutated BRAF–MAPK axis, as well as the GPD1 and ELOVL6 expression levels. A histopathological analysis of Malme-3M tumor sections showed extensive focal tumor necrosis in treated mice. An immunofluorescence study of tumor sections showed notable reductions in proliferation marker ki67 and the vasculogenesis marker CD31 in treated tumors. These findings promote LA as a potential nutraceutical lead for the control of the BRAF V600E mutant melanoma. Full article

This research presents a simple procedure for chemically modifying yeast (Saccharomyces cerevisiae) cells with nickel hexacyanoferrate (NiHCF) and ferric hexacyanoferrate, also known as Prussian blue (PB), to increase the conductivity of the yeast cell wall. Using linear sweep voltammetry, NiHCF-modified yeast and PB-modified yeast (NiHCF/yeast and PB/yeast, respectively) were found to have better cell wall conductivity in [Fe(CN)₆]³⁻ and glucose-containing phosphate-buffered solution than unmodified yeast. Spectrophotometric analysis showed that the modification of yeast cells with NiHCF had a less harmful effect on yeast cell viability than the modification of yeast cells with PB. The use of NiHCF/yeast and PB/yeast cells in the construction of a yeast-based fuel cell allowed the maximum power densities of 62.66 mW/m² and 94.09 mW/m² to be achieved. These values were much higher than those obtained using unmodified yeast cells (42.25 mW/m²). NiHCF/yeast and PB/yeast fuel cells were renewed by replenishing the yeast suspension in the anolyte or the FeCl₃ salt in the catholyte. This allowed 77.4% and 50.1% of the initial maximum power density of the fuel cells to be achieved. Full article

Cosmetically active compounds (CACs), both of lipophilic and hydrophilic origin, have difficulty reaching the deeper layers of the skin, and this shortcoming significantly reduces their efficacy. One such CAC that occurs naturally in the human body and displays many beneficial properties (via reducing fine lines and wrinkles, tightening skin, improving its elasticity, etc.) is the glycyl-L-histidyl-L-lysine tripeptide complex of copper (GHK–Cu). GHK–Cu is a fairly hydrophilic compound with limited permeation through the lipophilic stratum corneum. On the other hand, liposomes capable of encapsulating GHK–Cu may improve its permeation potential. The present review discusses various issues related to obtaining insight into the permeation of CACs through the skin. Methods for studying the transport of CACs encapsulated by liposomes and free GHK–Cu across the skin barrier are summarized. An analysis of the literature data reveals that the transport of liposomes containing GHK–Cu received little attention. This research gap gives an impetus to the methodological developments for assessing the effect of liposomes on GHK–Cu transportation and trafficking. Full article

The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group dl-alanine to synthesise a water-soluble Al³⁺ fluorescent probe (Probe A). Moreover, a water-soluble Fe³⁺ fluorescent probe (Probe B) was synthesised from coumarin-3-carboxylic acid and 3-hydroxyaminomethane. Probe A and Probe B exhibited good stability in the pH range of 4–9 in aqueous solutions, high sensitivity, as well as high selectivity for Al³⁺ and Fe³⁺; the detection limits for Al³⁺ and Fe³⁺ were 1.180 and 1.683 μmol/L, whereas the response times for Al³⁺ and Fe³⁺ were as low as 10 and 30 s, respectively. Electrostatic potential (ESP) analysis and density functional theory calculations identified the binding sites and fluorescence recognition mechanism; theoretical calculations showed that the enhanced fluorescence emission of Probe A when detecting Al³⁺ was due to the excited intramolecular proton transfer (ESIPT) effect, whereas the fluorescence quenching of Probe B when detecting Fe³⁺ was due to the electrons turning off fluorescence when binding through the photoelectron transfer (PET) mechanism. Full article

Malic acid-derived polyamides, polyhydrazides, and hydrazides exhibit strong potential for a variety of biological applications. This study demonstrates the synthesis of cobalt, silver, copper, zinc, and iron particles by a facile chemical reduction approach utilizing malic acid-derived polyamides, polyhydrazides, and hydrazides as stabilizing and reducing agents. Comprehensive characterization of the particles was performed using UV–Vis spectroscopy, FTIR, XRD, SEM, and EDX analysis. The synthesized particles included both zero-valent metals and oxides exhibiting mixed-phase compositions that may influence their functional properties. UV–vis analysis confirmed the formation of particles represented by the surface plasmon resonance (SPR) peaks specific to each metal particle. FTIR spectroscopy revealed the interaction of the metal particles with the polymer matrix owing to the significant contribution of functional groups in the processes of reduction and stabilization. Further structural insights were obtained via X-ray diffraction (XRD), which identified crystalline phases, and scanning electron microscopy (SEM), which demonstrated uniform morphologies. Additionally, energy-dispersive X-ray (EDX) analysis provided compositional details, affirming the purity and distribution of metallic elements. These findings highlight the potential of malic acid-derived polymers as versatile agents for nanoparticle synthesis with applications in catalysis, sensing, and biomedical technologies. Full article

Abstract: Multidrug-resistant (MDR) bacteria are becoming more and more common, which presents a serious threat to world health and could eventually render many of the antibiotics we currently use useless. The research and development of innovative antimicrobial tactics that can defeat these hardy infections are imperative in light of this predicament. Antimicrobial peptides (AMPs), which have attracted a lot of attention due to their distinct modes of action and capacity to elude conventional resistance mechanisms, are among the most promising of these tactics. As a promising substitute for conventional antibiotics, AMPs are a varied class of naturally occurring compounds that target bacteria membranes and disrupt cellular activities to demonstrate broad-spectrum antimicrobial activity. The objective of this study is to present a thorough summary of the current knowledge regarding AMP mechanisms against MDR bacteria, including immunological modulation, interactions with microbial membranes, and possible synergy with currently used antimicrobial drugs. In addition, we define the review’s scope to include the most recent developments in AMP research, emphasizing the innovations’ development, optimization, and therapeutic promise. We hope to emphasize the crucial role that AMPs will play in the future of antimicrobial therapy by bringing together recent research and highlighting current issues. We also hope to advocate for AMPs’ continued research and development as part of a comprehensive strategy to counteract the growing threat of antibiotic resistance. Full article

Transition metal oxides are considered promising anode materials for high performance flexible electrodes due to their abundant reserves and excellent specific capacity. However, their inherent low conductivity, large volume effect, and poor cycling performance limit their applications. Herein, we report a novel “spontaneous complexation and exfoliation” strategy for the fabrication of flexible MnO NCs@rGO thin-film electrodes, which overcomes the aforementioned drawbacks and pushes the mechanical flexibility and lithium-ion (Li⁺) storage performance to a higher level. The combination of large-area few-layer reduced graphene oxide (rGO) films and ultrafine MnO nanocrystals (MnO NCs) provides a high density of electrochemical active sites. Notably, the layer-by-layer embedded structure not only enables the MnO NCs@rGO electrodes to withstand various mechanical deformations but also produces a strong synergistic effect of enhanced reaction kinetics by providing an enlarged electrode/electrolyte contact area and reduced electron/ion transport resistance. The elaborately designed flexible MnO NCs@rGO anode provides a specific capacity of about 1220 mAh g⁻¹ over 1000 cycles, remarkable high-rate capacity (50.0 A g⁻¹), and exceptional cycling stability. Finally, the assembled flexible lithium-ion full cells achieve zero capacity loss during repeated large-angle bending, demonstrating immense potential as a high-performance flexible energy storage device. This work provides valuable insights into unique structural designs for durable and ultra-fast lithium ion batteries. Full article

This article presents the synthesis, electrophysical, and catalytic properties of a La_0.9MnO₃–LaFeO₃ nanocomposite material. The nanocomposite was synthesized via the sol–gel (Pechini) method. X-ray diffraction (XRD) analysis revealed a polycrystalline, biphasic perovskite structure combining both hexagonal and cubic symmetry. The microstructure and elemental composition, examined using field emission scanning electron microscopy (FESEM), indicated an average particle size of approximately 186.9 nm. The composite exhibits semiconducting behavior within the temperature ranges of 293–323 K and 343–393 K. Developing electrocatalysts free of precious metals for the hydrogen evolution reaction (HER) is increasingly important to facilitate the production of hydrogen from renewable sources. In this study, the conductive La_0.9MnO₃–LaFeO₃ composite was deposited on graphite and, for the first time, evaluated as an electrocatalyst for HER in acidic media. The resulting composite films were tested using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a glassy carbon electrode (GCE) setup, providing insights into their potential as effective, cost-efficient electrocatalysts. Full article

Six new triterpenoids, heritieras C–H (1–6), along with thirteen known triterpenoids (7–19), were isolated from the leaves of Heritiera littoralis. Their structures were identified by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HRESIMS), and by comparison with the literature. Anti-inflammatory activity of the isolates was evaluated using the lipopolysaccharide (LPS) stimulated RAW 264.7 cell model. Among the isolated triterpenoid, compounds 1, 12, 16, 17, and 18 demonstrated inhibitory activity against nitric oxide (NO) release, in which compound 18 exhibited the best activity with an IC₅₀ value of 18.13 μM. The potential anti-inflammatory mechanism was investigated using molecular docking. The triterpenoids from H. littoralis could be served as potential candidates for the development of new anti-inflammatory agents. Full article

Increasing the concentration of oxygen vacancies in ceria-based materials to solve the bottleneck of their applications in various fields has always been a research hotspot. In this paper, ceria-based cerium–oxygen–sulfur (Ce-O-S) composites that were composed of CeO₂, Ce₄O₄S₃, and Ce₂(SO₄)₃ were synthesized by a precipitation method. The compositional, structural, morphological, and light response characteristics of prepared Ce-O-S composites were investigated by various characterization techniques. The molar ratio of oxygen vacancies to lattice oxygen can reach a maximum of 1.83 with Ce-O-S composites. The band gap values of the Ce-O-S composites were less than 3.00 eV, and the minimum value was 2.89 eV (at pH 12), which successfully extended the light response range from the ultraviolet light region to the short-wave blue light region. The remarkable light response performance of Ce-O-S composites can be mainly attributed to the high proportion of oxygen vacancy. Moreover, the higher proportion of oxygen vacancies can be attributed to the doping of Ce (+3) and S (−2) in the lattice of CeO₂, and the synergistic effect of CeO₂, Ce₄O₄S₃, and Ce₂(SO₄)₃. Moreover, the ceria-based Ce-O-S composites with rich oxygen vacancy in this research can be applied in light blocking, photocatalysis, and other related fields. Full article

2,8-Dithia-5-aza-2,6-pyridinophane (L1) has been used as a receptor unit in the construction of the conjugated redox chemosensor 5-ferrocenylmethyl-2,8-dithia-5-aza-2,6-pyridinophane (L3). In order to further explore the coordination chemistry of L1, and comparatively, that of its structural analogue 2,11-dithia-5,8-diaza-2,6-pyridinophane (L2), featuring two secondary nitrogen atoms in the macrocyclic unit, the crystal structures of the new synthesised complexes [Pb(L1)(ClO₄)₂]·½CH₃CN, [Cu(L2)](ClO₄)₂·CH₃CN and [Cd(L2)(NO₃)]NO₃ were determined by X-ray diffraction analysis. The electrochemical response of L3 towards the metal ions Cu2+, Zn2+, Cd2+, Hg2+, and Pb2+ was investigated by cyclic voltammetry (CV) in CH₂Cl₂/CH₃CN 0.25:1 (v/v) mixture. Upon addition to L3 of increasing amounts of the aforementioned metal cations, the wave corresponding to the Fc+/Fc redox couple of the un-complexed L3 was gradually replaced by a new reversible wave at more positive potentials and corresponding to the Fc+/Fc redox couple of the complexed ligand. The maximum anodic shift of the ferrocene oxidation wave is observed in the presence of Pb2+ (230 mV), to which corresponds a reaction coupling efficiency (RCE) value as large as 7.9 × 103. The response selectivity of L3 is discussed in reference to the optical selectivity observed for conjugated chemosensors featuring L1 as receptor unit and different fluorogenic fragments as signalling units. Full article