In this study, two types of spent coffee grounds (SCG, Machine and Turkish) were tested in the production of SCG-biopolymer composite cups. The ob-jective was to develop a simple and sustainable preparation approach for SCG-based biocomposites, ensuring sufficient mechanical and thermal sta-bility for practical applications. Biocomposite cups, containing 55 to 72% of SCG were produced using sodium alginate as the primary polymer binder. To enhance mechanical performance, a secondary binder (additional poly-mer), either cellulose ether (carboxymethyl cellulose (CMC) or hydroxy-propyl cellulose (HPC)) or natural polysaccharides (dextran or pectin), was incorporated. Comprehensive characterisation was performed using fluorescence and FTIR spectroscopy, tensile testing, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Fluorescence spectroscopy/microscopy revealed a higher content of naturally fluorescent organic compounds in Machine SCG compared to Turkish SCG. FTIR spec-troscopy confirmed the successful SCG incorporation into the biopolymer matrix. Tensile testing showed that Machine SCG-based biocomposites were slightly more flexible than those prepared with Turkish SCG. Glass transition temperature (Tg) of SCG biocomposites depends on their composition and varied from around 75 to 100 degrees C. The TGA results demonstrated that SCG exhibit a greater thermal stability than both SCG-alginate biocomposites and SCG biocomposites containing additional polymers.
In the search for chemical compounds that strongly and selectively bind and inhibit one out of 12 catalytically active CA isozymes, a series of fluorinated substituted benzenesulfonamides was designed and synthesised. Substituents were intended to be stiff and have a limited conformational flexibility. We determined compound affinities using the fluorescence-based thermal shift assay. Afterward, we subtracted the binding-linked protonation reactions and calculated the intrinsic affinities, which were then used to establish the structure-affinity relationships. Compound 5 (2-(cyclohexylamino)-3,5,6-trifluoro-4-(phenylsulfonyl) benzenesulfonamide) exhibited an improved selectivity profile toward CAIX, a cancer-associated isozyme. The analysis of compound functional group contributions and the comparison with previously designed compounds provided insight toward a deeper understanding of the protein-ligand recognition principles for drug design.
This article describes the synthesis and properties of new methoxy-substituted triphenylamine-based enamines. Thermal, photophysical and electrochemical properties of the compounds are reported. In addition, the ionisation energies estimated by photoelectron emission spectroscopy and hole transporting properties examined by the time-of-flight method are discussed. The compounds form molecular glasses with glass transition temperatures of up to 91 degrees C. They exhibit a high thermal stability with 5% weight-loss temperatures above 420 degrees C. Their characteristic optical band-gaps are of 2.9 eV and the solid-state ionisation energies situate around 5.4 eV. One of the compounds shows a high hole mobility of 8.4 & times; 10-4 cm2/Vs at the electric field of 4 & times; 105 V/cm.
The nanostructuring of electrode surfaces is commonly employed to enhance the electrochemical performance of enzymatic glucose biosensors. However, the optimisation of nanostructure morphology and dimensions remains an incompletely explored area. In this work, three colloidal solutions of gold na-norods (AuNR), different in size, were synthesised. SEM analysis revealed that nanorods exhibited distinct lengths: 32.8 +/- 3.4 nm for AuNRI, 35.0 +/- 3.5 nm for AuNRII and 90.0 +/- 6.7 nm for AuNRIII. Glucose biosensors based on graphite rod electrodes modified with AuNR and glucose oxidase showed enhanced electrochemical performance. Notably, biosensors fabricated with AuNRI and AuNRIII achieved similar maximal current changes during the en-zymatic reaction (triangle Imax = 49.31 +/- 2.64 and 48.45 +/- 2.35 & micro;A, respectively), despite the pronounced difference in the electroactive surface area obtained after AuNR deposition (0.082 +/- 0.009 and 0.194 +/- 0.005 cm2, respectively). Moreover, the fabricated glucose biosensor based on AuNRI exhibited a linear range of practical relevance (0.1-8 mM), a low limit of detection (4.6 & micro;M), and is suitable for glucose detection in the diluted blood serum. Overall, the results indicate that morphological characteristics, including size, aspect ratio, and spatial organisation, play a crucial role in optimising the design and performance of enzymatic glucose biosensors.
The aim of this study was to quantify the actual melatonin content in commonly available over-the-counter melatonin sleep supplements marketed in Lithuania. For this purpose, a high-performance liquid chromatography (HPLC) method was optimised and validated. The calibration curve was linear (R2 = 0.9996) over a concentration range of 0.5-50.0 mg/L, and the limit of detection was 0.17 mg/L. Recoveries of melatonin from spiked supplement samples ranged from 96.8 to 104.1%, with relative standard deviation values below 3.2%. Melatonin was quantified in 20 commercial sleep supplements representing 10 brands and three dosage forms (capsules, tablets and liquids), with two different lots analysed for each brand. Overall, the measured melatonin content ranged from-7 to +26% relative to the labelled amount, indicating a low variability among melatonin products sold in Lithuania. Only one product contained melatonin amount outside the +/- 20% margin of the labelled claim. The least variable products were liquid supplements, which generally contained the simplest ingredient compositions.
The dry purification of biodiesel using natural adsorbents has emerged as a sustainable alternative to the traditional method of washing with water in biodiesel production. In this context, this study investigates the efficiency of talc and bentonite in the dry purification of biodiesel from babassu, a promising oilseed that is little used for biodiesel production. The biodiesel was produced by alkaline transesterification and purified with different concentrations of talc and bentonite. The adsorbents were characterised by X-ray diffraction, infrared spectroscopy and textural analysis. After purification, the physicochemical parameters of the biodiesel were analysed and compared with water-purified samples. Bentonite showed a higher surface area (76.685 m2/g) and pore volume (0.121 cc/g) compared to talc (8.610 m2/g and 0.029 cc/g). Both adsorbents efficiently reduced the acidity index, with bentonite being more effective, especially at a concentration of 3.0%. Moisture was significantly lower in samples treated with adsorbents, with bentonite standing out in ethyl biodiesel. The dielectric constant decreased with the use of adsorbents, indicating a greater removal of polar contaminants. Dry purification with talc and bentonite is efficient in improving the quality of babassu biodiesel, meeting the specifications of current legislation.
Corrosion is an unavoidable process in metals, but it can be effectively managed through various techniques. One such approach involves the use of environmentally friendly corrosion inhibitors, commonly referred to as green corrosion inhibitors. Moringa oleifera (MO) leaves are renowned for their high concentration of antioxidant compounds; however, their applications have primarily been limited to water purification and food ingredients. Addressing this gap, research was conducted to explore the potential of Moringa leaf extract as a green corrosion inhibitor for X70 steel. The study employed varying concentrations of the leaf extract (0.04, 0.08, 0.1 and 0.2 g center dot L-1) to identify the optimal performance under 3.5% NaCl conditions. The effectiveness of the MO leaf extract in reducing the corrosion rate was evaluated using Tafel polarisation and electrochemical impedance spectroscopy (EIS) tests. The results demonstrated a significant reduction in the corrosion rate, with the highest inhibition efficiency reaching 83% in the NaCl medium. scanning electron microscopy (SEM) analysis further confirmed the formation of a protective layer on the steel surface, consistent with findings from gravimetric and electrochemical studies. These results highlight the potential of Moringa leaf extract as a sustainable and effective corrosion inhibitor.
Glucose monitoring is essential for the management of diabetes and for ensuring an accurate analysis in clinical and food-related applications. In this study, a reagentless amperometric glucose biosensor was developed based on the layer-by-layer adsorption of 5-amino-1,10-phenanthroline (AP), 13 nm diameter gold nanoparticles (AuNPs), and glucose oxidase (GOx) onto a graphite rod electrode, followed by chemical cross-linking of GOx with glutaraldehyde vapour. AP acted as a redox mediator, enabling an efficient electron transfer, while AuNPs facilitated signal amplification. The biosensor exhibited a wide linear range (0.30-10.0 mM), low limits of detection and quantification (LOD 0.05 mM, LOQ 0.17 mM), a high repeatability (RSD 3.19%) and an acceptable reproducibility (RSD 5.51%), along with an excellent selectivity toward glucose and a satisfactory storage stability (86% signal retention over 7 days), and anti-interference performance against uric and ascorbic acids. These features demonstrate the biosensor's suitability for routine and point-of-care glucose monitoring. Furthermore, the proposed platform is versatile and can be adapted for the detection of other clinically or environmentally relevant analytes, highlighting its potential for broader analytical applications.
Ultraviolet surface-enhanced resonance Raman spectroscopy (UV-SERRS) offers the ultrasensitive, reliable and selective analysis and sensing of biomolecules due to the combination of surface-enhancement and resonance enhancement of the Raman signal of studied molecules. In this Review, we provide the background of the technique and discuss the challenges related to ultraviolet plasmonics as well as the ability to employ the non-plasmonic substrates. We also highlight the recent applications of UV-SERRS in analysis of biomolecules. Finally, the advantages and future directions of the method are provided.
In this study, a high-quality berry vodka, termed Berrovka, was produced using a mixture of berries-strawberries, raspberries, cherries, currants and gooseberries-cultivated and harvested in a household setting and processed into jam. The fermentation products of the mixed-berry jam waste were subsequently distilled, and the resulting distillates were analysed using gas chromatography-mass spectrometry (GC-MS). Analytical conditions for GC-MS were selected and optimised to facilitate the qualitative and quantitative assessment. Ethanol was identified as the primary fermentation product, as anticipated. Several volatile by-products, including acetaldehyde, methanol, propanol, isobutanol, butanol, and others, were identified. The analysis of sequential distillation fractions indicated a marked decrease in acetaldehyde concentration as distillation progressed. Concentrations of propanol, isobutanol, and isoamyl alcohol exhibited a gradual decline, whereas methanol levels remained relatively constant throughout the distillation process. These findings highlight the potential for producing a high-quality distilled spirit from household berry jam waste, with controlled levels of fermentation by-products through optimised distillation.
This study presents the synthesis and characterisation of KH550-modified cardanol-based phenolic hybrid resins. The hybrid resins were prepared via a two-step process: (1) synthesis of cardanol-based phenolic resin (CPR) through the condensation of cardanol and paraformaldehyde (1:1.3 molar ratio of phenolic hydroxyl groups to aldehyde groups), followed by (2) ultrasound-assisted grafting of gamma-aminopropyltriethoxy silane (KH550) at varying mass ratios (5 and 15 wt%, denoted as CPR-K5 and CPR-K15, respectively). Hydrolysis of KH550 generated silanol (Si-OH) groups, which underwent covalent grafting and condensation reactions with the phenolic hydroxyl groups (-OH) and hydroxymethyl groups (-CH2OH) of CPR to form Si-O-C crosslinked networks, as confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) revealed the homogeneous dispersion of the organosilicon phase within the resin matrix. Thermogravimetric analysis (TGA) demonstrated a significant enhancement in thermal stability, with the char yield at 800 degrees C increasing from 7.8% (neat CPR) to 22.1% (CPR-K15). Stress-strain tests verified the enhanced mechanical performance, with the Young's modulus of CPR-K5 reaching 104.7 MPa (representing a similar to 512% increase compared to neat CPR, 17.1 MPa) and that of CPR-K15 being 52.2 MPa (similar to 205% increase vs neat CPR). This work provides a facile strategy for preparing sustainable hybrid resins with tailored thermomechanical properties, addressing the inherent brittleness and a low char yield of conventional cardanol-based phenolic resins. The resulting materials show potential for high-temperature structural applications and flame-retardant composites.
A renewable mercury film silver-based electrode (Hg(Ag)FE) in combination with adsorptive stripping voltammetry is evinced as a simple and fast approach for a simultaneous quantification of indium(III) and bismuth(III) in natural water samples. In order to effectively preconcentrate and obtain signals from both analytes in one measurement, cupferron was used as a complexing agent. Optimal conditions were found to be as follows: 0.1 mol L-1 acetate buffer (pH = 4.6), 3 x 10-4 mol L-1 cupferron, accumulation potential of-0.1 V and accumulation time of 60 s. A linear response of In(III) and Bi(III) in a concentration range of 2 x 10-9 to 1 x 10-7 mol L-1 (r = 0.9986) was gained with a detection limit of 6.5 x 10-10 mol L-1 for In(III) and 8.3 x 10-10 mol L-1 for Bi(III), respectively. Analytical results of the analysis of river water samples demonstrated that the elaborated voltammetric method is apposite for direct environmental water analysis.
Landfill leachate is highly challenging to treat due to its complex and unstable composition, containing high concentrations of ammonia nitrogen, chemical oxygen demand (COD), heavy metals, and persistent organic pollutants such as polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). In this study, a novel heterogeneous photo-Fenton catalyst, Fe-CoBDC@Fe3O4, was synthesised via a thermosolvent method using terephthalic acid regenerated from PET waste. The catalyst was employed for the degradation of recalcitrant compounds in leachate following pretreatment with an activated solid reactor. Upon UV irradiation (240 nm), the Fe-CoBDC@Fe3O4 catalyst generates electron-hole pairs, where the holes (h+) oxidise water or hydroxyl ions (OH-) to form hydroxyl radicals (center dot OH), which in turn degrade organic pollutants. Optimal treatment conditions were identified as a catalyst dosage of 1 g/L, H2O2 dosage of 0.8 mL, pH 3.0, and a reaction time of 30 min. Under these conditions, the removal efficiency of 97% for COD, 85% for PAHs and 84% for PCBs was achieved. These results demonstrate that Fe-CoBDC@Fe3O4 is a highly effective and sustainable photo-Fenton catalyst for the treatment of refractory compounds in industrial leachate.
The seeds of Thespesia populnea, a mangrove-associated plant, remain understudied despite their potential bioactivity. Among various extracts, the acetone extract showed the highest polyphenol (186.13 +/- 0.06 mg GAE/g) and flavonoid (475.71 +/- 8.08 mg QE/g) contents. Antioxidant assays demonstrated a significant free radical scavenging activity. It exhibited strong antimicrobial effects, with inhibition zones of 16-18 mm against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and MIC values of 28 mu g/mL (Candida albicans) and 51 mu g/mL (Aspergillus niger). The MTT assay revealed selective cytotoxicity against MCF-7 breast cancer cells (IC50 = 76.8 +/- 2.1 mu g/mL) over L929 normal fibroblasts (IC50 = 286.34 +/- 1.8 mu g/mL). GC-MS and FTIR analyses confirmed the presence of bioactive phytochemicals responsible for these effects. This is the first comprehensive report highlighting the antioxidant, antimicrobial and anticancer potential of T. populnea seed extract, supporting its relevance as a promising natural candidate for biomedical applications.
This study introduces an integral metric of electrocatalytic activity, which is based on the comparison of the area under the polarisation curve in current density vs overpotential coordinates over a specific chosen overpotential range. This metric is applied to evaluate and compare several electrocatalysts, allowing for a more comprehensive understanding of electrocatalytic performance. Unlike traditional metrics, which characterise electrocatalyst behaviour under specific conditions (e.g. a particular overpotential or current density), the proposed integral metric provides a broader evaluation over a wide operational range. This approach is particularly useful for electrocatalysts with different Tafel slopes and polarisation characteristics. The metric is shown to be invariant to the shape of the polarisation curve and can be applied even when the exact form of the analytical dependence is unknown. The application of this metric holds promise for both fundamental studies in electrocatalysis and for practical applications in selecting the most efficient electrocatalysts for various technological processes.
The antiradical/antioxidant properties of folic acid (FA) and its conformational derivatives-7,8-dihydrofolate (DHF), 5,6,7,8-tetrahydrofolate (THF) and 5-formyl-5,6,7,8-tetrahydrofolate (5-FTHF)-were studied at the physiological temperature and pH in the micellar aqueous system of the model reaction of methyl linoleate peroxidation with molecular oxygen. It was established that folates exhibit antioxidant properties, thereby inhibiting the peroxidation of methyl linoleate. Quantitative kinetic studies of selected folates revealed the comparative growing order of the antiradical/antioxidant reactivities: FA < 5-FTHF < THF congruent to DHF. Investigation of the antioxidant properties of folates is urgent for understanding their role in the prevention of pathologies in the body. They may have potential in treating numerous pathological conditions in which oxidative stress is a clinically important component.
Small cell lung cancer (SCLC), although less common than non-small cell lung cancer (NSCLC), is an aggressive and lethal form of lung cancer. Even if it was diagnosed and started being treated early, it still contributes to poor survival rates. Standard therapies, including platinum-based chemotherapy and immune checkpoint inhibitors, offer limited and short-lived benefits due to the rapid disease relapse and widespread metastasis. One of the promising strategies for the new drug against SCLC development is the rational design of 9H-carbazole or other structurally similar chromophores with an alkyl phosphonic acid moiety, expecting dual-targeting ability, potentially targeting both nuclear and cytoplasmic effectors involved in SCLC progression and resistance. The aim of this work was to synthesise phenothiazine, phenoxazine, anthraquinone and substituted carbazole derivatives, containing an alkyl phosphonic acid moiety and to evaluate their in vitro antiproliferative activity using the well-established anthracycline-resistant H69AR small cell lung cancer (SCLC) cell model. The results demonstrate that 9H-carbazole derivatives bearing alkyl phosphonic acid groups could be explored as a promising scaffold class for the further development of compounds against drug-resistant SCLC.
Winter savory (Satureja montana L.) is well known to exhibit strong antioxidant and antibacterial properties. Winter savory is rarely found growing wild in Lithuania; however, as a common garden plant, it has been the subject of only a few studies. The goal of this research was to determine the mineral composition of winter savory and evaluate how well seven different solvents compositions - deionised water, 2% sodium dodecyl sulfate (SDS) and 2% Triton X-100 - could extract phytochemicals. The results showed that the elemental composiwas also determined that the total concentration of phenolic compounds in the plant extracts varied depending on the solvent and morphological part used. Concentrations ranged from 23.91 mg g-1 in the stems when ethanol was used to 138.96 mg g-1 in the leaves when methanol was used. Additionally, phenolic acids ranged from 6.45 mg g-1 in the aqueous exfactant Triton X-100. Flavonoid content varied from 9.94 mg g-1 in flower extracts obtained with distilled water to 151.39 mg g-1 in leaf extracts when the surfactant SDS was used. Winter savory extracts exhibited a high radical scavenging activity by DPPH assays ranging from 13.01 to 85.71%. The strongest antibacterial effect was observed in 2% SDS stem extract against Bacillus subtilis. Considering all the analysis performed, we can conclude that SDS is the most effective solvent for winter savory.
In this paper, we try to summarise some historically identified structural and catalytic properties of an important super-family of flavoenzymes, the oxygen-insensitive bacterial nitroreductases (NRs). We also review how these mechanistic properties have underpinned diverse roles in medicine and biomedical research, with an emphasis on the last decade. NRs perform the NAD(P)H-dependent two/four-electron reduction of nitroaromatic compounds (ArNO2) and the two-electron reduction of quinones (Q) without the formation of free radicals of these compounds. This has significant implications for their behaviour in living systems. We reviewed the structural, catalytic and potentiometric properties of NRs and their oxidant substrate specificity, as well as the structural factors influencing it. Biomedical aspects of the function and application of NRs were also reviewed, including the importance of NRs in antibiotic resistance, their applications in cancer gene therapy, and NR-mediated cellular ablation technologies.
Electrochemical processes are central to energy storage, catalysis, corrosion and sensing, yet understanding and optimising these systems remains challenging. Physics-informed neural networks (PINNs) offer a promising approach by integrating physical laws into machine learning models for improved interpretability and accuracy. In this work, we develop a PINN to simulate the diffusion and electric-field-driven transport of Zn2+ ions released from ZnO nanoparticles in the beetroot-Swiss chard-leaf tissue. The model embeds the Poisson's equation for electric potential and the Nernst-Planck equation for ion flux into the network's loss function, enabling it to learn physically consistent potential and concentration fields with minimal data. The PINN predictions reveal that Zn2+ ions accumulate near leaf edges, a phenomenon also observed experimentally. Using the trained model, we evaluate microelectrode sensor array designs and find that a hexagonal electrode layout would capture the edge-concentrated Zn2+ distribution more effectively than a uniform grid. This case study demonstrates how AI modelling informed by physics can accurately replicate experimental trends and guide the design of better electrochemical sensors. The results highlight the broader potential of PINNs to advance electrochemical research by combining data-driven learning with established physical electrochemical principles.
