Compounds

This study evaluates the feasibility and effectiveness of using immobilized pectinase enzymes for juice processing to reduce cloudiness while preserving nutritional and bioactive properties. The research is driven by the increasing demand for innovative food products that offer enhanced functionality and health benefits. It focuses on the development and application of immobilized biocatalysts in bioprocessing, specifically using pectinase encapsulated in a sol–gel matrix. Reaction parameters for the interaction between immobilized pectinase and its primary substrate, pectin, were optimized through systematic experimentation. Optimal conditions were established, achieving enhanced enzyme activity and stability with 0.15 g of lens-shaped capsules containing 10.0 mg/mL pectinase in 24-well microplates as microreactors. Kinetic studies indicated improved substrate affinity after immobilization (K_m = 0.115 mg/mL), particularly when magnetized (K_mi = 0.041 mg/mL). Operational stability and reusability assessments demonstrated potential for extended use with magnetized pectinase capsules retaining higher residual activity after a fourth reuse cycle (155% > 75%). The application of immobilized pectinase in processing peach nectar successfully reduced cloudiness and increased the release of bioactive compounds, enhancing antioxidant and anti-inflammatory activities, as evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and the albumin method, respectively. In vitro digestion studies revealed dynamic activity profile changes, highlighting the impact of juice bioprocessing on bioavailability. Full article

This study investigates the rheological behavior of cellulose microfiber suspensions derived from kahili ginger stems (Hedychium gardnerianum), an invasive species, in two adhesive matrices: a commercial water-based adhesive (Coplaseal^®) and a casein-based adhesive made from non-food-grade milk, referred to as K and S samples, respectively. Rheological analyses were performed using oscillatory and rotational shear tests conducted at 25 °C, 50 °C, and 75 °C to assess the materials’ viscoelastic properties more comprehensively. Oscillatory tests across a frequency range of 1–100 rad/s assessed the storage modulus (G′) and loss modulus (G″), while rotational shear tests evaluated apparent viscosity and shear stress across shear rates from 0.1 to 1000 s⁻¹. Fiber-free samples consistently showed lower moduli than fiber-containing samples at all frequencies. The incorporation of fibers increased the dynamic moduli in both K and S samples, with a quasi-plateau observed at lower frequencies, suggesting solid-like behavior. This trend was consistent in all tested temperatures. As frequencies increased, the fiber network was disrupted, transitioning the samples to fluid-like behavior, with a marked increase in G′ and G″. This transition was more pronounced in K samples, especially above 10 rad/s at 25 °C and 50 °C, but less evident at 75 °C. This shift from solid-like to fluid-like behavior reflects the transition from percolation effects at low frequencies to matrix-dominated responses at high frequencies. In contrast, S samples displayed a wider frequency range for the quasi-plateau, with less pronounced moduli changes at higher frequencies. At 75 °C, the moduli of fiber-containing and fiber-free S samples nearly converged at higher frequencies, indicating similar effects of the fiber and matrix components. Both fiber-reinforced and non-reinforced suspensions exhibited pseudoplastic (shear-thinning) behavior. Fiber-containing samples exhibited higher initial viscosity, with K samples displaying greater differences between fiber-reinforced and non-reinforced systems compared to S samples, where the gap was narrower. Interestingly, S samples exhibited overall higher viscosity than K samples, implying a reduced influence of fibers on the viscosity in the S matrix. This preliminary study highlights the complex interactions between cellulosic fiber networks, adhesive matrices, and rheological conditions. The findings provide a foundation for optimizing the development of sustainable biocomposites, particularly in applications requiring precise tuning of rheological properties. Full article

Advancements in membrane separation techniques will expand the applications and requirements for highly specialized, inventive, efficient, and resistant separation materials. The selective separation of rare earth elements (REEs) is one of the expanding applications of membrane-based techniques, as their use is becoming more widespread. Membrane techniques are becoming increasingly desired as environmentally friendly, straightforward methods for treating wastewater and separating metals. For the separation of REEs, an innovative impregnated mixed-matrix membrane (IMMM) technique was developed in this study. It provides a selective, efficient, and reusable method that is suitable for industrial applications. Terbium was selectively adsorbed from other REEs using organophosphorus IMMM with a loading capacity of 113.2 mg/g in 3 h and was reused three times without destroying the initial membrane. Solvent impregnation is thought to offer specific chelation sites that are selective for terbium separation. Full article

Over the past few years, researchers have developed the alloy Al-Mg-Zn(-Cu), a new aluminum alloy based on the technique of ‘crossover alloying’. The main strengthening phase of this novel alloy is T-Mg₃₂(Al, X)₄₉(X is Zn and Cu) after ageing and hardening. This alloy system has exceptional strength and corrosion resistance, making it a promising candidate for applications in fields like automotive, marine, aerospace, and many others. In this work, the research progress of the Al-Mg-Zn(-Cu) alloy based on microstructure control, composition, design, and properties has been reviewed. Future directions for the research of this alloy are highlighted, too. In this work, crossover alloys are presented as a potential novel class of Al alloys implicating a pioneering design approach, with particular emphasis on the aeronautical and aerospace field in which radiation resistance results are one hundred times higher than traditional precipitation hardening alloys. Full article

Powders with a phase composition including syngenite (K₂Ca(SO₄)₂·H₂O) and/or calcium sulfate dihydrate (gypsum, CaSO₄·2H₂O) were synthesized from the powder of calcium carbonate (CaCO₃) and water solutions of potassium hydrosulfate (KHSO₄) of various concentrations (0.5 M, 1 M, and 2 M). A molar ratio of starting salts, KHSO₄/CaCO₃ = 2, was used to provide the formation of syngenite (K₂Ca(SO₄)₂·H₂O). But when using a 0.5 M water solution of potassium hydrosulfate (KHSO₄), the phase composition of the synthesized powder was presented by calcium sulfate dihydrate (gypsum, CaSO₄·2H₂O). When using 1 M and 2 M water solutions of potassium hydrosulfate (KHSO₄), the syngenite (K₂Ca(SO₄)₂·H₂O) was found as the predominant phase in synthesized powders. According to estimations made from thermal analysis data, powders synthesized using 1.0 M and 2.0 M water solutions of potassium hydrosulfate (KHSO₄) contained no more than 7.9 and 1.9 mass % of calcium sulfate dihydrate (gypsum, CaSO₄·2H₂O), respectively. The phase composition of products isolated from mother liquors via water evaporation consisted of syngenite (K₂Ca(SO₄)₂·H₂O) and potassium sulfate (arcanite, K₂SO₄). Synthesized powders can be used in preparation of biocompatible bioresorbable materials with phase compositions in the K₂O-CaO-SO₃-H₂O system; as matrix of thermo- or photo-luminescent materials; as components reducing the setting time and increasing the strength of sulfate cements; in the fertilizing industry; and also as components of Martian regolith simulants. Full article

The smallest strained, saturated N-heterocycles, such as aziridine, can be a valuable building block in synthetic organic chemistry. Ring-opening reactions with various nucleophiles could be the most important strategy to synthesize various value-added molecular entities. Therefore, regioselective ring-opening reactions of aziridines with various heteroatomic nucleophiles and carbon nucleophiles establish a useful synthetic methodology to synthesize biologically relevant β-functionalized alkylamines. The regio-selective ring-opening of aziridines is highly dependent on the substrate combination, and stereochemical control is challenging for Lewis acid-promoted reactions. Therefore, the development of a robust, catalytic ring-opening process that assists in the accurate prediction of regioselectivity and stereochemistry is highly desirable. Consequently, a large number of publications detailing distinct methods for aziridine ring-opening reactions can be found in the literature. In this review, we discuss several transition metal catalyzed cross-coupling reaction protocols for the ring opening of substituted aziridines with various carbon nucleophiles. Full article

This review discusses the development and applications of bioconjugates derived from natural hydroxycinnamic acids (HCA), such as coumaric, sinapic, ferulic, and caffeic acids, combined with various biomaterials. These bioconjugates offer a range of benefits including antioxidant properties, UV protection, customized hydrophilic–lipophilic balance, improved safety, solubility, emolliency, biocompatibility, biodegradability, and targeted delivery for biomedical, cosmetic, and food applications. The increasing demand for natural products in the biomedical, cosmetic, and food industries has led to the exploration of these hydroxycinnamic acids and their derivatives. We discuss the synthesis and modification of hydroxycinnamic acids with biomaterials such as ω-hydroxy fatty acids, castor and lesquerella oils, glycerol, isosorbides, and synthetic polyethylene glycol to form functional phenolipids for biomedical, sunscreen, and skincare applications. Encapsulation techniques with β-cyclodextrins and modification of polymeric supports like polysaccharides and starch are discussed for enhancing bioavailability and solubility and targeted delivery. The fine-tuned development of bioconjugates from hydroxycinnamic acids using glycerol to modify the hydrophilic–lipophilic balance, substitution by water-soluble carboxylic acid groups, vegetable oil-based phenolipids, polysaccharides, and PEGylation provide enhanced dual functionalities and offer a promising avenue for creating effective products across various applications. Full article

In recent years, the femtosecond laser ablation of hard dental tissues has stimulated great interest in preparing accurate and reproducible dental cavities. Many studies on the changes induced in the surface morphology, structure, and composition of human teeth have been performed using various advanced experimental techniques. Vibrational spectroscopies such as Fourier transform infrared (FT-IR) and Raman spectroscopy have been adopted for obtaining precise information about changes induced by femtosecond laser ablation in human teeth. Their two main components, dentin and enamel, have been carefully investigated. The analysis of the vibrational spectra has allowed for the identification of the optimal working parameters for efficient laser ablation processes. In the present review, a brief description of the abovementioned vibrational techniques is reported, and the principal results obtained by these two vibrational spectroscopies in the study of femtosecond laser ablated teeth are summarized and analyzed. Full article

To investigate how hydrodynamic cavitation (HC) affects the adsorption of sodium oleate (NaOl) on diaspore and kaolinite surfaces, a comparative study on NaOl adsorption was conducted under different conditions. The flotation and separation of the minerals were also examined with and without HC pretreatment of NaOl. The results show that short-term HC pretreatment of NaOl solutions did not induce a measurable change in the chemical structure of NaOl, but produced micro-nanobubbles (MNBs) and resulted in decreases in the surface tension and viscosity of liquids. When MNBs interacted with minerals, their anchor on solids could affect the contact angles, zeta potentials, and surface NaOl adsorption toward minerals. At low NaOl concentrations, the presence of MNBs reduced the NaOl adsorption capacity and particles’ zeta potential while increasing the minerals’ contact angle. At higher NaOl concentrations, the presence of MNBs promoted NaOl adsorption, further increased the minerals’ contact angle, and further decreases the particles’ zeta potential. Additionally, the flotation and separation of minerals can be enhanced at low NaOl concentrations, largely due to the enhanced bubble mineralization through the selective surface-anchoring of MNBs on diaspore. However, the separation efficiency might deteriorate at high NaOl concentrations, though the presence of MNBs amplified the divergences in minerals’ surface wettability and zeta potentials. Full article

Article presents a comparison of surface structure study methods, such as atomic force microscopy, scanning and transition electron microscopy in terms of metallic materials 3D-printed using the laser powder bed fusion technique. The main features, advantages, disadvantages of atomic force microscopy as a research method for the LPBF synthesized samples are discussed in the context of hard magnetic material, specifically Nd-Fe-B. The ability to provide qualitative grain structure analysis with the high-resolution images of atomic force microscopy is comprehensively studied. For confirmation good applicability of the above-mentioned method for LPBF sample analysis images of a magnetic domain structure obtained via atomic force microscopy are presented. Thus, the applicability of atomic force microscopy to the quality microstructural investigation of metallic materials obtained by LPBF is demonstrated. Full article

In the present study, XRD, SEM/EDS, Raman, EMR/EPR spectroscopy, and vibrating sample magnetometry (VSM) were used to analyze the reduction of hematite by the carbonization products of waste activated sludge (WAS) at 500–1000 °C. The reduction process includes the following steps: α-Fe₂O₃ → Fe₂O₃ + Fe₃O₄ (T_tr~500 °C) → Fe₃O₄ (T_tr~600–700 °C) → FeO → Fe_amorph. (T_tr~1000 °C). The prevalence of certain phase compositions at different hematite reduction temperatures makes it possible to predict the areas viable for the application of reduced oxides: adsorbents (after T_tr~500 °C) → soft ferromagnetic materials (after T_tr~600–700 °C) → electrically engineered amorphous iron (after T_tr~1000 °C). Full article

Zinc oxide (ZnO) is one of the most versatile semiconductor materials with many potential applications. Understanding the interactions between the surface chemistry of ZnO along with its physico-chemical properties are essential for the development of ZnO as a robust photocatalyst for the removal of aqueous pollutants. We report on the fabrication of nanoparticle-like porous ZnO films and the correlation between the fabrication process parameters, particle size, surface oxygen vacancies (SOV), photoluminescence and photocatalytic performance. The synthesis route is unique, as highly porous zinc layers with nanoscale grains were first grown via magnetron sputtering, a vacuum-based technique, and subsequently annealed at temperatures of 400 °C, 600 °C and 800 °C in oxygen flow to oxidise them to zinc oxide (ZnO) while maintaining their porosity. Our results show that as the annealing temperature increases, nanoparticle agglomeration increases, and thus there is a decrease in the active sites for the photocatalytic reaction. However, for selected samples the annealing leads to an increase of the photocatalytic efficiency, which we explain based on the analysis of defects in the material, based on photoluminescence (PL). PL analysis showed that in the material the transition between the conduction band and the oxygen vacancy is responsible for the green emission centered at 525 nm, but the photocatalytic activity correlated best with surface states—related emission. Full article

This study aims at investigating the chemical composition of root, stem and leaf essential oils from Ivorian Synedrella nodiflora, with the root oil being described for the first time. Sixty, fifty-one and forty-nine constituents were, respectively identified in the root, stem and leaf oils using a combination of GC(RI), GC-MS and ¹³C-NMR analyses. They accounted for 95.6–97.3%, 92.6–97.6% and 93.3–98.8% of the total composition, respectively. The main components of the root oil samples were γ-curcumene, (E)-β-caryophyllene, α-curcumene and curcuphenyl acetate. Three stem oil samples (S1, S2a, S3) were dominated by myrcene and limonene, while the most abundant components of sample S2b were thymol, germacrene D and β-elemene. (E)-β-caryophyllene and germacrene D were the major compounds of the leaf oil. Hierarchical cluster and principal component statistical analyses were performed and confirmed that the location does not influence the chemical composition. Group I consisted of the seven leaf oil samples, group II consisted of four stem oil samples and group III consisted of three root oil samples. The root oil composition differed considerably from the stem and leaf oil composition due to the presence of curcumene derivatives as major constituents. The leaf oil showed significant amounts of (E)-β-caryophyllene and germacrene D, while the stem oil stood out for its high myrcene, limonene and thymol contents. Full article

Zinc oxide (ZnO) nanoparticles are widely recognized for their distinctive properties and versatile applications across diverse technological domains. However, traditional methods of synthesizing ZnO nanoparticles are characterized by environmental incompatibility, high costs, and the necessity for precise process control to attain the intended particle dimensions and morphology. The present study utilized a chives extract as a sustainable and eco-friendly fuel in the solution combustion synthesized (SCS) process to produce ZnO nanoparticles. The investigation encompassed an analysis of the impact of the fuel-to-oxidizer (F/O) ratio on the synthesized ZnO nanoparticles’ size, morphology, and crystallinity. X-ray diffraction (XRD) results showed that the particle’s crystallite size increased significantly from 12 nm to 42 nm after decreasing the F/O ratio. Furthermore, electron microscopic imagery and FTIR spectroscopy outcomes indicated that modifications in the F/O ratio significantly influenced the SCS process parameters, forming particles with diverse morphologies, including spherical, pyramid-like, hexagonal, and hexagonal plate-like shapes. This research presents a straightforward, cost-efficient, and environmentally sustainable approach for producing ZnO nanoparticles with diverse morphologies, presenting a broad potential for various applications. Full article

Cardiovascular diseases (CVDs) are a global health problem. The mortality associated with them is one of the highest. Essentially, CVDs occur when the heart or blood vessels are damaged. Oxidative stress is an imbalance between the production of reactive oxygen species (free radicals) and antioxidant defenses. Increased production of reactive oxygen species can cause cardiac and vascular injuries, leading to CVDs. Antioxidant therapy has been shown to have beneficial effects on CVDs. Plants are a rich source of bioactive antioxidants on our planet. Several classes of these compounds have been identified. Among them, carotenoids and phenolic compounds are the most potent antioxidants. This review summarizes the role of some carotenoids (a/β-carotene, lycopene and lutein), polyphenols such as phenolic acids (caffeic, p-coumaric, ferulic and chlorogenic acids), flavonoids (quercetin, kaempferol and epigallocatechin gallate), and hydroxytyrosol in mitigating CVDs by studying their biological antioxidant mechanisms. Through detailed analysis, we aim to provide a deeper understanding of how these natural compounds can be integrated into cardiovascular health strategies to help reduce the overall burden of CVD. Full article

The electrodeposition of copper (Cu), silver (Ag), and their alloys has been a subject of interest since the 19th century. Primarily due to their exceptional features such as good mechanical hardness and electrical conductivity, high resistance to corrosion, and electromigration, Cu–Ag electrodeposits continue to be investigated and developed to improve their properties for different applications. This paper reviews the state of the art in the field of electroplated Cu–Ag alloys in an aqueous solution, with particular emphasis on the observed properties and variety of electrochemical processes used to produce high-quality materials. Moreover, this review paper focuses on the experimental conditions employed for Cu–Ag electrodeposition, intending to understand the basis and manipulate the processes to obtain coatings with superior characteristics and for attractive usage. Finally, the most trending applications of these coatings are discussed depending on different parameters of electrodeposition to provide prospects for potential research. Full article

Dental erosion represents the gradual and irreversible depletion of dental hard tissues due to a chemical process, independent of bacterial influence. It has emerged as a notable clinical concern in recent years, primarily attributed to substantial lifestyle shifts resulting in the heightened intake and frequency of acid-containing foods and beverages. Apart from the extrinsic erosive agents derived from external sources, such as dietary habits or medication, intrinsic erosive agents may exist due to pathological reasons with the contents of the stomach including gastric juice, mainly composed of hydrochloric acid, being their sole source. Currently, bioactive materials are used in various forms for the prevention of dental erosion. Such materials include, among others, bioactive glasses (BAGs). BAGs are a type of glass that, when in contact with biological fluids, can elicit a specific biological response. When they come into contact with bodily fluids, they can initiate a series of processes, including the formation of a hydroxyapatite layer on the glass surface. This bioactivity is particularly advantageous in medical and dental applications, where BAGs are used for bone regeneration, tissue repair, and dental restorative or preventive techniques. The aim of this literature review was to analyze and discuss the role of BAGs in protecting the tooth structures from dental erosion. The analysis of the existing literature regarding this topic indicated that the use of BAGs in preventive treatments against tooth erosion can be useful in dental practice. Further clinical evidence is necessary to confirm the effectiveness of the particular preventive measures. Full article

In an era where the search for innovative drug leads faces challenges, our study pivots towards exploring the untapped potential of plant-derived compounds, focusing on the period of 2021 to 2022. We assess the classes of compounds these new structures belong to; the plants and families these compounds belong to; and the degree of novelty of the compound compared with already-known structures. The review was conducted following the Preferred Reporting Items for Systematics Reviews and Meta-Analyses (PRISMA) statement checklist for the guided reporting of systematic reviews. A total of 464 articles were selected for the new compounds of natural origin survey. We included 117 complete articles in this review and reported approximately 109 new structures elucidated during the years 2021 and 2022. Many of the compounds showed small structural variations in relation to already-known molecules. For some, however, this small modification was decisive for the biological activity reported, demonstrating the importance of descriptive phytochemical studies. Full article