Mixed Solution Research Articles

Elucidation of complexation mechanism of rosmarinic acid and berberine

Polyphenols are known to form complexes with various organic compounds. This ability can may change the chemical or physical properties of the compounds involved and may even affect their efficacy in the case of drugs. Our research revealed that mixing solutions of the polyphenol rosmarinic acid (RA) and berberine (Ber), a widely used and pharmacologically important isoquinoline alkaloid, resulted in the formation of a precipitate of the RA–Ber complex at a molar ratio of 1:1. This was confirmed using 1H NMR and Fourier Transform Infrared Spectroscopy. To elucidate the formation mechanism of the precipitate, the behavior of RA and Ber in an aqueous solution was examined using 1H NMR, indicating the formation of the RA–Ber complex at a molar ratio of 1:1, consistent with the results of precipitation. Additionally, we investigated the steric structure of the RA–Ber complex in an aqueous solution using molecular modeling calculations. These calculations suggested the existence of seven types different steric structures of the RA–Ber complex, primarily stabilized by π–π interactions. Based on these results, we concluded that mixing RA and Ber solutions in an aqueous environment results in the formation of RA–Ber complexes with seven types different steric structures at a molar ratio of 1:1. The precipitate forms because these complexes are less water-soluble than either RA or Ber alone.

Simultaneous quantitative analysis of multiple metabolites using label-free surface-enhanced Raman spectroscopy and explainable deep learning

Metabolites serve as vital biomarkers, reflecting physiological and pathological states and offering insights into disease progression and early detection. This study introduces an advanced analytical technique integrating label-free Surface-Enhanced Raman Spectroscopy (SERS) with deep learning, and leverages SHAP (SHapley Additive exPlanations) to provide a visual interpretative analysis of the predictive rationale of the deep learning model, facilitating simultaneous detection and quantitative analysis of multiple metabolites. Monolayer silver nanoparticle SERS substrates were fabricated via a triple-phase interfacial self-assembly method, which captured complex spectral information of target metabolites in mixed solutions. A custom-built deep neural network model with multi-channel feature extraction was employed to predict the concentrations of uric acid (R2 = 0.976), xanthine (R2 = 0.971), hypoxanthine (R2 = 0.977), and creatinine (R2 = 0.940). The method’s scalability was validated as the performance remained consistent with an increasing number of simultaneous targets. This approach offers a sensitive, cost-effective, and rapid alternative for metabolite analysis, with significant implications for clinical diagnostics and personalized medicine.

Performance of Single Nanopore and Multi-Pore Membranes for Blue Energy.

The salinity gradient power extracted from the mixing of electrolyte solutions at different concentrations through selective nanoporous membranes is a promising route to renewable energy. However, several challenges need to be addressed to make this technology profitable, one of the most relevant being the increase of the extractable power per membrane area. Here, the performance of asymmetric conical and bullet-shaped nanopores in a 50 nm thick membrane are studied via electrohydrodynamic simulations, varying the pore radius, curvature, and surface charge. The output power reaches ~60 pW per pore for positively charged membranes (surface charge σw=160 mC/m2) and ~30 pW for negatively charges ones, σw=-160 mC/m2 and it is robust to minor variations of nanopore shape and radius. A theoretical argument that takes into account the interaction among neighbour pores allows to extrapolate the single-pore performance to multi-pore membranes showing that power densities from tens to hundreds of W/m2 can be reached by proper tuning of the nanopore number density and the boundary layer thickness. Our model for scaling single-pore performance to multi-pore membrane can be applied also to experimental data providing a simple tool to effectively compare different nanopore membranes in blue energy applications.

Guanidinium‐Based Covalent Organic Framework Membranes for Superior Mono‐ and Divalent Cations Separation

Biological membranes exhibit extraordinary efficiency in processing ion permeability and selectivity. However, creating artificial membranes for an ideal ion separation is still challenging due to the subtle distinctions in valence and size among different ions. In the realm of biological recognition, the ultimate selectivity of ion channels is considered to stem from the specific binding interactions and appropriate charge density. Designing artificial membranes to achieve similar performance not only helps the understanding of complex ion transport in bioprocesses but also facilitates critical industrial separations. Inspiring by the remarkable performance in biological systems, a guanidinium‐based covalent organic framework membrane is designed, which exhibits an excellent capability to recognize mono‐/divalent cations, achieving K+/Mg2+ selectivity up to 202 in a mixed salt solution. Furthermore, the membrane displays rapid ion transport owing to the uniform sub‐2 nm channels. The experimental results and molecular dynamics simulations illustrate that the charge‐assisted hydrogen bonding sites and the Cl− counter ions within 1D channels play critical roles in cations sieving. Specifically, divalent ions passing through the positively charged channels need to overcome higher energy barriers than monovalent ions. These findings offer promising avenues for the development of advanced multifunctional membranes for efficient ion separation and sustainable water‐related separations.

Efficient removal of multiple heavy metal ions from wastewater using task-specific hydrophobic deep eutectic solvents: A circular approach

In this study, four hydrophobic deep eutectic solvents (HDESs) were prepared by combining lidocaine or ibuprofen with heptanoic acid in varying molar ratios for the efficient removal of heavy metal ions (HMIs) such as Cd(II), Pb(II), and Ni(II) from wastewater. The prepared HDESs were characterized using spectroscopic and thermal techniques, and their physicochemical properties, including density and viscosity, were investigated as a function of temperature. Liquid-liquid extraction (LLE) experiments were optimized for key parameters such as metal ion concentration, volume ratio, and pH. Among the HDESs, HDES1 (lidocaine-heptanoic acid in a 1:1 molar ratio) demonstrated superior extraction performance in both individual and mixed metal ion solutions, simulating real industrial conditions. Reusability studies of HDES1 showed consistent extraction performance over five consecutive cycles, indicating the sustainability of the process. The findings highlight the potential of HDES-based LLE for industrial applications, offering a cost-effective and environmentally friendly solution for HMI removal.

Manipulating overcompensation of poly (allylamine hydrochloride) in layer-by-layer nanofiltration membranes for Mg2+/Li+ separation

Surface modification of the positive charges in the polyamide thin-film composite nanofiltration (NF) membranes has been explored for separation of Mg2+/Li+ via Donnan exclusion. However, manipulation of the surface charges in layer-by-layer (LBL) NF membranes presents significant challenges because the overall charge within the entire separation layer, rather than just the top surface, provides effective Donnan effect. In this work, we reported a facile approach to increase the positive charge within poly (styrene sulfonate) (PSS)/poly (allylamine hydrochloride) (PAH) LBL NF membranes. A significant improvement in the permselectivity of (PSS/PAH)2.5 NF membranes was achieved by varying the PAH concentration from 0.001 M to 0.1 M. The increased PAH concentration led to overcompensation within the separation layer, resulting in a higher charge density and increase in the rejection of MgCl2, MgSO4 and LiCl, but decline in the rejection of Na2SO4. Although the pore size slightly reduced, the overall improvement in the permselectivty was mainly attributed to the Donnan exclusion effect. The optimal membrane, prepared using a PAH concentration of 0.1 M, showed a high pure water permeance of 10.9 L m−2 h−1 bar−1 with a MgCl2 rejection of 96.6 %, and the highest separation factor SMg,Li of 19.6 for mixed salt solutions. The assembly process of LBL membranes typically involved two stages during each coating cycle: polyelectrolyte (PE) adsorption and diffusion. PAH concentration primarily affected the adsorption process, while the diffusion process was influenced by NaCl concentration. Higher concentration of PAH and NaCl led to coiled conformation. This collectively led to the overcompensation of PAH. Among these, PAH concentration was identified as a more important factor for overcompensation. This study highlights the versatility of LBL NF membranes, demonstrating their potential for precise ion separation through tailored surface charge manipulation.

Limosilactobacillus Fermentun ZS09 Can Improve Antibiotic-Induced Motor Dysfunction in Mice by Regulating the Brain-Gut Functions.

When consumed in appropriate quantities, probiotics, which are live microorganisms, are good for health. In this study, a mouse model of antibiotic-induced dyskinesia was established using a sterile mixed antibiotic solution to investigate the preventive impact of Limosilactobacillus fermentum ZS09 (LFZS09) on this condition in mice. Following modeling, alterations in the serum and brain tissue of mice were assessed for motor measures such as running and swimming, malondialdehyde (MDA), superoxide dismutase, reduced glutathione, interleukin (IL-6, IL-10), and tumor necrosis factor (TNF)-α. The mouse cecum was used to evaluate the relative mRNA expression levels of the intestinal barrier genes, namely occludin-1, zona occludens-1 (ZO-1), and claudin-1. The relative mRNA expression levels of cAMP-response element binding protein (CREB), extracellular signal-regulated kinase (ERK), and brain-derived neurotrophic factor (BDNF) genes in the mouse brain tissue were also evaluated. Compared with the model group, LFZS09 considerably increased the swimming and running duration of mice, significantly decreased the levels of the inflammatory factors TNF-α and IL-6 and increased SOD expression in the mouse brain, and decreased MDA accumulation in the mouse brain and serum. Furthermore, LFZS09 upregulated occludin-1 gene expression in the cecal tissue to maintain the intestinal barrier, which in turn maintained the normal physiological function of the body. LFZS09 also enhanced the effect of BDNF and increased the expression of BDNF metabolic pathway-related genes, namely CREB, ERK1/2, and BDNF, in the mouse brain tissue. LFZS09 increased the number of Lactobacillus and Bifidobacterium in the gut of mice with motor dysregulation, and decreased the number of Enterococcus and Clostridium perfringens. The findings indicate that LFZS09 regulates antibiotic-induced motor impairment in mice, thereby offering a theoretical foundation for future studies and probiotic or parabiotics production aimed at augmenting motor function.

Novel sol-gel derived layered double oxides and layered double oxide/γ-Al2O3 with tunable selectivity as promising adsorbents for L-lactate uptake from the myoblast culture medium

Cultured meat production, a biotechnological solution for global protein demand and sustainability, faces economic challenges due to the high demand for cell culture medium. Contamination with cell metabolites, particularly L-lactate, impedes myoblast proliferation in high-density suspension culture. Eliminating L-lactate is crucial for reusing the medium and overcoming economic barriers in mass myoblast culture. Retaining essential nutrients like D-glucose, amino acids, and vitamins after L-lactate removal is imperative for sustained myoblast growth. This study proposes a sustainable and economically feasible adsorption technique utilizing novel sol-gel derived Mg-Al layered double oxides and Mg-Al layered double oxide/γ-Al2O3 with tunable selectivity as a promising tool for L-lactate uptake from the myoblast medium. In an aqueous solution, L-lactate uptake and selectivity over D-glucose were enhanced with the decrease in total Mg/Al ratio and crystallinity, increase in Al2O3 dispersion in adsorbent, specific surface area, and porosity. The latter was achieved successfully by metal alkoxide sol-gel method employing an organic structure-directing agent, where LDO/amorphous alumina nanohybrid with Mg/Al = 1.23 was successfully prepared in mixed methanol-ethanol solution in a relatively short time. A simple mixture of Mg-Al LDO with Mg/Al = 2 and nano-γ-Al2O3 prepared by a sustainable and economically feasible co-precipitation method was found to have comparable efficiency and selectivity to a costly sol-gel derived material. In myoblast medium, lower total Mg/Al was associated with higher cytocompatibility, pH-stability, and selectivity, while surface properties of materials did not play a significant role. Nano-γ-Al2O3 was identified as the most promising material for selective L-lactate uptake from the myoblast culture medium. Thus, further optimization of the medium treatment process with nano-γ-Al2O3 can realize cost-effective high-density myoblast culture with circular use of the medium – a novel sustainable process in the biotechnology field.

Strengthening Resilience and Sustainability for Post-Disaster Recovery: A Comparative Law and Economics Analysis on Smart Mixes Between Mechanisms

This article advocates smart mixes of mechanisms of post-disaster recovery in terms of boosting resilience and sustainability through liability rules, government intervention, insurance, and their combinations. Liability rules can provide compensation to victims and, in theory, also reduce disaster risks, while they have their limits in practice. The government widely intervenes in disaster compensation in many countries, but it faces challenges in how it can intervene fairly and efficiently, whether through informal channels, such as ad hoc charity, or structured approaches, such as compensation funds. As governments may struggle to provide efficient and effective compensation ex post, insurance may offer proactive solutions with models of first-party catastrophe insurance and third-party liability insurance ex ante. Where market failure, liability failure, and government failure may all arise, a smart mix of mechanisms is often preferable from a law and economic perspective, rather than relying solely on one framework. However, upon examining empirical evidence regarding the effectiveness of these instruments in China, the UK, France, Germany, and Turkey, it becomes apparent that a mix of mechanisms is not always applied in an effective manner. Models of mandatory comprehensive disaster insurance, and Public–Private Partnership (PPP), which both receive government intervention as a last resort to the market and liability failures, can reach the goal of more effective compensation for disaster victims, risk prevention and resilience when faced with disaster recovery, and should therefore be substantially implemented beyond the current levels. To be clear, the proposed mix of solutions mainly focuses on legal and economic dimensions which are rather limited, ignoring, for example, building codes for structures and physical interventions.

Rapid and simultaneous determination of mixed pesticide residues in apple using SERS coupled with multivariate analysis

This study aims to apply multivariate analysis algorithms for modeling the same spectra, for simultaneous determination of pymetrozine and carbendazim residues in apple. To mitigate the impact of competitive adsorption, SERS spectra are obtained from mixed solutions of pymetrozine and carbendazim at varying concentration ratios, which are then utilized for modeling. Results suggest that the PLSR model based on full-band SNV processed spectra shows the best performance for predicting pymetrozine and carbendazim contents, with R2 p of 0.9751 and 0.9779, RMSEP of 0.0492 and 0.5531 mg/L, RPD of 6.4297 and 6.8246, respectively. This model yielded R2 p of 0.9644 and 0.9671, RMSEP of 0.0747 and 0.8247 mg/L, RPD of 5.3857 and 5.6066 for pymetrozine and carbendazim in apple, respectively. The findings suggest that the proposed approach is suitable for simultaneous detection of pymetrozine and carbendazim in apples, offering a novel avenue for monitoring food safety.

Chemometric advances in COD analysis: Overcoming turbidity interference with a Hybrid PLS-ANN approach

In the current context of environmental protection, the accuracy of water quality analyses is crucial, especially chemical oxygen demand (COD) analyses. COD is a key indicator of organic pollutants in water, and is often compromised by turbidity interference at UV wavelengths. Faced with this turbidity challenge, this innovative study proposes an integrated approach, using in situ UV sensors and advanced Chemometric techniques, exploiting the synergy between PLS (Partial Least Square) and ANN (Artificial Neural Network). The research is divided into three main sections: (i) assessment of turbidity interference, (ii) development of a turbidity prediction model and (iii) elaboration of the COD compensation and prediction model. Turbidity significantly alters the UV-Visible absorbance spectrum of COD. By analyzing mixed solutions of COD and turbidity, we quantified this interference and established a turbidity prediction model using spectral areas between 303.5 and 700 nm. Interval PLS identified the most informative spectral regions for COD concentration, highlighting the 200–250 nm interval. To address turbidity interference, we developed a hybrid model combining PLS and ANN regression, and turbidity measurements are incorporated as an explanatory term in the model. This hybrid approach relies on in situ UV sensors to directly capture UV absorbance data in the field and applies robust chemometric models to accurately distinguish the UV absorbance contributions of organic compounds and turbidity. The method not only compensates for the interfering effect of turbidity, but also allows turbidity information to be used to refine COD predictions. Model performance, evaluated using R², RMSE, and MAE, showed a significant increase in R² to 0.9972, and decreases in RMSE to 0.94 and MAE to 0.64, demonstrating the method's effectiveness in correcting turbidity-induced deviations and improving COD prediction accuracy. The results of the evaluation on real data show high performance metrics, with recovery percentages close to 100 % and low RMSE and MAE values, indicating the model’s robust ability to predict COD in the presence of suspended particles.

Ion Identification and Ultralow Concentration Sensing with Liquid Flexoelectricity.

The isolation and concentration of electrical charges at ionic-electronic interfaces are prevalent phenomena that impede effective communication between ionic and electronic systems. Detecting these concentrated charges at the interface is crucial for applications, such as signal transmission and ion detection. Current electrical detection approaches introduce additional ionic-electronic interfaces via metallic electrodes with an external stimulating voltage, which alters the initial ion distributions at the interfaces. In this work, we introduce the flexoelectricity of liquids to examine the electrical charge aggregation at ionic-electronic interfaces under cyclic mechanical loads. The measured electrical responses reflect the coupling phenomena between the flexoelectricity and the electric double layer. This proposed approach demonstrates the capability to quantify ion types and concentrations at interfaces. Furthermore, it can identify ion types in mixed solutions and offers high sensitivity at ultralow concentrations. This work promotes a nonchemical, general mechanical method for charge detection at ionic-electronic interfaces.

APPLICATION OF PCR FOR THE DETECTION OF VIRAL INFECTIONS IN THE HONEYBEE Apis mellifera IN THE NORTHERN REGIONS OF UKRAINE

Aim. This study investigated viruses of the western honeybee (Apis mellifera) from the northern regions of Ukraine using polymerase chain reaction (PCR). Methods. To identify honeybee viruses, oligonucleotide primers, which are specific to a gene fragment encoding the capsid protein and a fragment of the RNA-dependent RNA polymerase gene, were used. The reaction mixture contained 12.5 μL of master mix solution (DNA polymerase, dNTPs, and buffer), 1 μL of each primer (20 pmol/μL), 2 μL of cDNA, and water to a total volume of 25 μL. PCR products were visualized in a 2% agarose gel. Results. In the Zhytomyr region in Apis mellifera was revealed for the first time the presence of four viruses representing different taxonomic groups, in particular Israeli Acute Paralysis Virus (IAPV), Sacbrood Virus (SBV), Deformed Wing Virus (DWV) and Chronic Bee Paralysis Virus (CBPV). Three of these viruses (SBV, DWV, and CBPV) were detected in the Kyiv region, while two (SBV and DWV) were identified in the Chernihiv region. Conclusions. The obtained data indicate the widespread distribution of Apis mellifera honeybee viruses in the northern regions of Ukraine. The use of PCR to detect bee viruses will contribute to the development of effective methods for improving the health of bee colonies.

Optimizing the surface quality of electrochemical machined Ni-based single crystal superalloy via manipulation of phase and dendrite dissolution

The transpassive dissolution behaviors of Ni-based single crystal superalloy in 10 %NaCl, 10 %NaNO3, and mixed solution are investigated by using potentiodynamic polarization, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The alloy exhibits opposite yet complementary dissolution characteristics in NaCl and NaNO3 solutions. The different responses of γ/γ′ phases to Cl− and NO3− contribute to the opposite dissolution behaviors of dendrites and interdendritic regions. The surface flatness is noticeably enhanced in mixed solution due to the synchronous dissolution of the γ/γ′ phases. Our work paves the way for obtaining high-quality surface in electrochemical machining of single crystal superalloys.

Fabrication of ion imprinted diethylenetriamine pentaacetic acid-polyethylenimine modified magnetic graphene oxide for selective adsorption of Ce(III)

Selective recovery of rare earth elements is essential for both sustainable exploitation of rare earth resources and environmental remediation. Herein, Ce(Ⅲ) imprinted diethylenetriamine pentaacetic acid-polyethylenimine modified magnetic graphene oxide (IIP-DTPA-PEI-MGO) was fabricated for selective adsorption of Ce(Ⅲ). Adsorption efficiency and selectivity performance of IIP-DTPA-PEI-MGO towards Ce(Ⅲ) were evaluated via batch adsorption targeted at single and mixed solution, respectively. Adsorption mechanism was elucidated based on versatile adsorption fittings (isotherms, kinetics, thermodynamics) and spectroscopic tests (XPS, FTIR). Result presents, maximum adsorption efficiency of IIP-DTPA-PEI-MGO for Ce(III) is reached at pH = 5 in 30 min, demonstrating superior efficiency. The maximum mono layer adsorption capacity determined by the Langmuir model is 281.69 mg g−1. After adsorption, 75.65 % of original Ce(Ⅲ) is transferred into Ce(Ⅳ), while 24.35 % remain as Ce(Ⅲ). Furthermore, by virtue of its paramagnetic property, IIP-DTPA-PEI-MGO can be easily recovered for cyclic adsorption, thereby keeping adsorption quantity 90.44 mg g−1 on Ce(Ⅲ) in five consecutive cycles. Owing to ion imprinting sites, IIP-DTPA-PEI-MGO exhibits selectivity coefficient 1.34, 1.69, 2.32, 2.96, 15.24, 10.51 towards Ce(III) for binary solution Ce/La, Ce/Nd, Ce/Eu, Ce/Dy, Ce/Cu, Ce/Cr, respectively. In terms of adsorption mechanism, versatile functional groups O-H, C-N, C-O in IIP-DTPA-PEI-MGO provide heterogeneous affinity for Ce(Ⅲ), inducing chemical adsorption. This work provides a novel approach towards fabricating magnetic bio adsorbent for selective recovery of Ce(Ⅲ).

Consumer liking of steamed green Chinese cabbage (Brassica rapa ssp. chinensis) cultivated in formulated vegetable waste-based organic hydroponic solutions

Chinese cabbage or pak choy (Brassica rapa ssp. chinensis) is often consumed because of its high nutritional content and several health advantages. Due to their promotion as being healthier and more ecologically friendly, hydroponic vegetables have seen a recent spike in consumer interest. The production of Chinese cabbage involved the processing of the vegetable waste to create various hydroponic solution formulations (F1 = banana peels, eggshells, and bean sprouts; F2 = banana humps, onion peels, bean sprouts, and moringa leaves; F3 = moringa leaves, onion peels, and bean sprouts; and F4 = AB Mix solution). They were applied at concentrations of 600, 900, 1,200, and 1,500 parts per million. The aim of this study was to investigate the relationship between the type of hydroponic growth solutions and Chinese cabbage customer acceptance. As a result, using a hedonic test of consumer liking, a panel of 32 untrained individuals was asked to show their liking score on sensory attributes of Chinese cabbage. There was a significant difference in the color liking of Chinese cabbage as an effect of hydroponic solution formulation. However, both organic vegetable waste-based formulations did not statistically substantially affect consumer acceptance, which includes color, taste, flavor, texture, and overall liking. Ultimately, vegetable waste-based organic formulations can be used to produce Chinese cabbage that is as acceptable to customers as those prepared with inorganic AB-Mix solution.

Manufacturing and characterization of simulated fission product (FP)-doped uranium–plutonium mixed oxide solid solutions (FP = Zr, Nd, Sm, and Gd)

Seven uranium–plutonium mixed oxides (MOX) comprising 10 and 20 mol% of solid simulated fission products (FPs) were prepared via powder metallurgy. Zirconium, neodymium, samarium, and gadolinium were selected as the FPs owing to their high fission yields and solubility within the uranium–plutonium fluorite structure. A laboratory-scale manufacturing process was developed to prepare solid solutions that are prerequisites for thermodynamical investigations. The microstructure and crystal structure of the specimens were analyzed. Furthermore, a mechanistic approach toward cation interdiffusion is proposed. Finally, our hybrid crystallographic model was employed to re-evaluate the ionic radii of the species constituting the FP-MOX samples.

Influences of surface active-groups on the exothermic properties and oxidation of coal molecules

In this study, coal samples' reactive group contents were changed using extractants, and the effects of the reactive group contents spontaneous coal combustion were investigated using infrared spectroscopy, thermogravimetry/derivative thermogravimetry, and differential scanning calorimetry. The results showed that the coal samples' hydroxyl group contents decreased in the order ethylenediamine (3.832 %) > N-methyl-2-pyrollidone mixed solution (2.091 %) > petroleum ether (0.882 %) > toluene (0.495 %) and that the hydroxyl group content was inversely related to the characteristic temperature point. RDG analysis showed that ethylenediamine formed N–H–O hydrogen bonds with hydroxyl-group-bearing molecules, coal molecules formed C–H–O hydrogen bonds with NMP molecules, petroleum ether generated a cumulative dispersive force with aliphatic side chains, and toluene molecules' benzene rings formed a very stable spatial structure with coal molecules' benzene rings. The thermogravimetry/derivative thermogravimetry curves showed that because the characteristic temperature points of the extracted coal samples moved to the high-temperature region from T5 onward, the coal samples had to be heated to a higher temperature to reach the energy required for the reaction. From the DSC thermograms, the exergy decreased in the order toluene (110.68 J/g) > NMP (110.52 J/g) > ethylenediamine (78.29 J/g) > petroleum ether (65.45 J/g). With increasing temperature from T1 to T6, the Pearson correlation coefficients of the alcoholic and phenolic hydroxyl groups were calculated at −0.7, −0.72, −0.93, −0.84, −0.8, −0.8, and −0.93 and −0.72, −0.91, −0.83, −0.79, −0.815, and −0.91, respectively, indicating that the hydroxyl group content influenced the coal's spontaneous combustion more than the other groups' contents.

Skill mix among healthcare workers during the Covid-19 pandemic – a scoping review

Abstract Background The problem of human resource shortages in health care was highlighted during the Covid-19 pandemic in many countries around the world. Various solutions have been implemented to cope with the crisis, one of which is the skill mix of medical and peri-medical staff. The aim of the scoping review was to systematise knowledge about the skill mix of healthcare workers during the Covid-19 pandemic. Methods The review was conducted in five scientific databases including Cinahl Ultimate, Web of Science, Medline (PubMed), Embase and Scopus. The review included studies published from 2020 until July 2023, presenting original research on the skill mix of health care workers. Results A total of 5039 records were identified in the databases and 27 articles were included in the final analysis. Of the included studies, 14 were conducted in Western and Southern Europe. Most of the studies included in the review were conducted among nurses (n = 12), pharmacists (n = 11) and doctors (n = 6). The majority of studies concerned re-allocating tasks (n = 9) and re-allocating tasks and introducing or changing teamwork (n = 7). Research covered psychological aspects of work, patient safety, work reorganisation and training and collaboration. Many studies also focused on difficulties and barriers related to skill mix, such as blurring of responsibilities and role ambiguity. The review did not identify any studies conducted among laboratory diagnosticians, medical coordinators or surgical assistants. In addition, there were no studies of skill mix in Central and Eastern Europe during the pandemic. Conclusions Given that skill mix may be one of the solutions to reduce the negative impact of staff shortages, more research should be conducted in this area. Healthcare professionals should be involved in decision-making processes related to the granting of new competencies or the creation of new professions/functions in healthcare. Key messages • It is necessary to involve health professionals in the process of creating new skill mix solutions. • More research is needed on skill mix in times of crisis, particularly in Central and Eastern Europe.

The precipitate structure of copper-based antibacterial and antiviral agents enhances their longevity for kitchen use

The transmission of bacteria through cooking surfaces, the handles of hot plates, and cookware that is not cleaned frequently can pose a problem. In this study, a copper ion-based mixed solution (CBMS) containing only inorganic ions with controlled acidity was assessed as a new antibacterial and antiviral agent. We analysed the structure of the precipitates, and various deposits measuring a few micrometres were observed on the substrates. We have defined these deposits as strongly bonded scaly copper dispersion (SBSCD) structures.The antibacterial copper component of the liquid agent changed over time after application; this mechanism appears to be responsible for the maintenance of antibacterial performance.CBMS demonstrates high safety for the human body and can be applied to stainless steel materials used in kitchens and tables. It exhibits a sustained antibacterial effect over time, and its antibacterial properties can be continuously maintained.