Search Results (3,750)

Extraction of metal ions from polluted waters and immobilization of metals in contaminated soils can be conducted using zeolites—porous aluminosilicate ion exchangers. The uptake of copper and zinc ions by the Georgian natural heulandite was studied under conditions of interaction of the zeolite with solutions (“liquid-phase” ion exchange) and powders (“solid-state” ion exchange) of the corresponding salts. The aim of the study was to compare the effect of the two procedures on the chemical composition and structure of the zeolite. It was found that the “liquid-phase” procedure provides a higher degree of uptake, particularly of zinc ions. Ion-exchange causes slight dealumination without decationization. Uptake of divalent ions occurs mainly through the leaching of sodium ions. According to X-ray data of ion-exchanged samples, the uptake of copper and zinc does not change the crystal structure of the zeolite framework, but nitrogen adsorption measurements show that ion exchange affects the mesoporous structure: solution treatment reduces the specific total pore volume and leads to the appearance of pores with a diameter of 4 nm. The “solid-state” procedure leads to an increase in specific total pore volume mainly due to an increase in the number of relatively small nanosized pores. Full article

Lead contamination remains a critical global concern due to its persistent toxicity, bioaccumulative nature, and widespread occurrence in water, food, and industrial environments. The accurate, cost-effective, and rapid detection of lead ions (Pb²⁺) is essential for protecting public health and ensuring environmental safety. Among the available techniques, potentiometric sensors, particularly ion-selective electrodes (ISEs), have emerged as practical tools owing to their simplicity, portability, low power requirements, and high selectivity. This review summarizes recent progress in lead-selective potentiometry, with an emphasis on electrode architectures and material innovations that enhance analytical performance. Reported sensors achieve detection limits as low as 10⁻¹⁰ M, broad linear ranges typically spanning 10⁻¹⁰–10⁻² M, and near-Nernstian sensitivities of ~28–31 mV per decade. Many designs also demonstrate reproducible responses in complex matrices. Comparative analysis highlights advances in traditional liquid-contact electrodes and modern solid-contact designs modified with nanomaterials, ionic liquids, and conducting polymers. Current challenges—including long-term stability, calibration frequency, and selectivity against competing metal ions—are discussed, and future directions for more sensitive, selective, and user-friendly Pb²⁺ sensors are outlined. Full article

Carbon dioxide (CO₂) released from natural or even anthropogenic sources may lead to an increase in the average global temperature and ultimately a climate shift. Thus, protecting the environment by reducing CO₂ concentration is a global concern. The recent approach of integrating CO₂ through capture, utilization, and storage seems to be an effective eradication technique. Even though a wide range of CO₂ capture strategies have been successfully adopted, there is an urgent need to compare these based on their advantages and weaknesses to define the development direction for future perspectives. Several materials have been used for capturing CO₂. Thus, we have elaborated and compared the current state of CO₂ capture strategies, including post-combustion CO₂ capture and direct air CO₂ capture. Strategies adopted under post-combustion CO₂ capture, including liquid- and solid-based sorbents, membrane-based separators, and electrochemical reduction, have been explained in detail, including their advantages, weaknesses, and potential risks. Thus, this review presents a thorough analysis of CO₂ capture in terms of material developments and manufacturing techniques, with some research gaps for future development. Full article

Accurate assessment of protein content in Foods for Special Medical Purposes (FSMPs) is critical for patients with chronic kidney disease, who require tightly regulated protein intake. This study aimed to develop and apply a rapid, low-volume, and reproducible microchip-based gel electrophoresis method for analyzing total nitrogen (TN) content and electrophoretic profiles in FSMPs. Products of different consistencies (powder, liquid, yoghurt-like) were tested to evaluate the influence of common additives (e.g., milk proteins, stabilizers, sweeteners) on TN levels and protein patterns. The results revealed considerable variation in fractions among brands, largely attributable to additive composition. Notably, TN levels often exceeded the declared protein content, potentially leading to unintended nitrogen overconsumption in clinical settings. Statistical analysis identified significant TN differences between infant and adult FSMPs in liquid formulations, while powdered forms showed no such distinction. These findings highlight the clinical importance of precise analytical monitoring, as discrepancies between measured TN and labeled protein content could compromise dietary management in vulnerable populations. The proposed method provides a reliable tool for FSMP quality control and supports safer nutritional planning in therapeutic diets. Full article

This study investigates how three flat-tube connector structures—conventional, ribbed flat-tube, and flange-connected—affect solid oxide fuel cell (SOFC) performance. The analysis employs a multi-physics modeling approach to examine the coupled effects of flow fields, gas species transfer, electrochemical reaction, and solid–liquid heat transfer. Results indicate that, under specific conditions, adding internal connector structures can enhance gas transport within the cell, leading to improvements in current density and output power. The flange-connected structure SOFC demonstrated superior output performance, particularly at a flange length of 30 mm, at which it achieved a 4.13% increase in power density compared to the conventional flat-tube SOFC and promoted a more uniform temperature distribution, effectively alleviating uneven temperature distribution inside the cell. Full article

Mismanagement of rural wastewater can lead to environmental contamination with the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Fungi with bioremediating potential constitute a sustainable alternative to decontaminate such wastewater before its reuse. This study evaluated the ability of Aspergillus oryzae pellets to remove 2,4-D from natural and sterile rural wastewater (i.e., with/without native microbiota). The pellets were produced by incubating conidial solutions of A. oryzae strains RCA2, RCA4, RCA5, and RCA10 in synthetic wastewater for 21 days at 25 °C. The wastewater samples were characterized physicochemically and microbiologically upon arrival at the laboratory. Afterwards, they were supplemented with 1, 2.5, or 5 mmol L⁻¹ of 2,4-D and inoculated with the pellets. Physicochemical characterization was repeated throughout the experiment. Herbicide removal and the presence of 2,4-D degradation intermediate, 2,4-dichlorophenol (2,4-DCP), were assessed through high-pressure liquid chromatography with UV/Vis detection (HPLC-UV) and mass spectrometry. At the beginning of the assay, the macro- and micronutrient content in the samples were suitable to sustain fungal growth. By the end, pH had increased and sodium and nitrate levels decreased in comparison with the control. RCA2, RCA4, and RCA10 removed over 80% of 2,4-D after 7 days of incubation, at the three herbicide concentrations tested. Moreover, wet fungal biomass had increased by the end of the assay. These findings demonstrate that RCA2, RCA4, and RCA10 can grow, form pellets, and remove 2,4-D in natural rural wastewater, which makes them potential candidates for bioremediation strategies aimed at improving the quality of water set to be reused. Full article

In high-power insulated gate bipolar transistor (IGBT) module thermal management, the structural design of microchannel cooling plates plays a crucial role in determining heat dissipation efficiency and temperature uniformity. This study focuses on the effects of honeycomb-structured unit dimensions and arrangements, as well as inlet/outlet configurations of the cooling plate on its thermal and flow performance. Additionally, the influence of different coolant inlet velocities and temperatures is investigated. Under constant coolant flow rate and boundary conditions, four design configurations with varying pore widths and channel spacings were evaluated numerically. The results indicate that the optimized honeycomb structure can reduce the module’s peak temperature by approximately 8.7 K while significantly improving temperature uniformity and maintaining a moderate pressure drop. Moreover, increasing the number of inlets and outlets effectively lowers the pressure drop and enhances thermal uniformity. Although increasing the coolant flow rate and reducing the inlet temperature can further improve cooling performance, these measures also lead to notable increases in energy consumption and pressure loss. Therefore, a trade-off between thermal enhancement and system energy efficiency must be considered in practical applications. The findings of this study provide practical guidance for the design optimization of high-efficiency microchannel liquid cooling systems in power electronic applications. Full article

Background: Antimicrobial resistance is a growing global health concern that requires multiple strategies to be tackled effectively. While the discovery of new antimicrobial molecules is essential, the repurposing of existing compounds also plays a significant role. Standard methods to evaluate antimicrobial efficacy, regulated by the Committee on Antimicrobial Susceptibility Testing (EUCAST) and the Clinical and Laboratory Standards Institute (CLSI), such as the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), are available. However, several potential antimicrobics show interference with these standard methods, resulting in underestimated activity and their premature dismissal from further studies. This work compares reference methods in evaluating different compounds with unique physico-chemical characteristics. We aim to demonstrate that combining different susceptibility tests is mandatory for a successful preclinical screening of antimicrobial compounds. Methods: A selection of substances including natural extracts, both free and in the form of nanocomposites with fumed silica, ionic liquids, ozonated oils, commercial and pure antibiotics, was tested using broth microdilution, disk diffusion, and agar dilution. These methods were chosen following EUCAST and CLSI guidelines, and comparisons were made to evaluate their applicability and limitations for non-conventional substances. Results: The study highlighted significant variability in the outcomes depending on the method used, especially for substances with intrinsic properties such as high viscosity, poor solubility, or specific interactions with the testing medium. In several cases, the use of a single standard method failed to accurately reflect the real antimicrobial activity, leading to potential misinterpretation of effectiveness. Conclusions: A combined methodological approach is recommended to overcome the limitations of individual techniques. The integration of multiple reference methods offers a more accurate screening strategy for identifying and characterizing new and repurposed antimicrobials. Full article

The “abnormal” properties of ice and liquid water can be explained by a hybrid quantum/classical framework based on objective facts. Internal decoherence due to the low dissociation energy of the H-bond and the strong electric dipole moment lead to a quantum condensate of O atoms dressed with classical oscillators and a degenerate electric field. These classical oscillators are either subject to equipartition in the liquid or enslaved to the field interference in the ice. A set of four observables and the degeneracy entropy explain the heat capacities, temperatures, and latent heats of the quantum phase transition; the super-thermal-insulator state of the ice; the transition between high- and low-density liquids by supercooling; AND the temperature of the liquid’s maximum density. The condensate also describes an aerosol of water droplets. In conclusion, quantum condensates turn out to be an essential part of our everyday environment. Full article

Infrastructure development in permafrost regions continues to face growing challenges from frost heaves and thaw settlement. The traditional frost heave theory considers that soil freezing is caused by the migration of liquid water in the soil; however, existing engineering practice shows that the migration of water vapor during the freezing process cannot be neglected. Based on the hydrothermal–air migration theory of unsaturated soils and their frost heave mechanism, this study established a coupled hydrothermal–air frost heave model for unsaturated silty clay under unidirectional freezing conditions. The computational model was verified through indoor modelling tests. The entire process of water vapor migration, moisture accumulation, and condensation-induced ice formation in unsaturated silty clay was comprehensively reproduced by numerical simulation. The results showed that the moisture field is redistributed during the freezing process of unsaturated soil. The increase in volumetric ice content in the frozen zone is due mainly to the migration of water vapor. Liquid water and water vapor in the unfrozen zone migrate towards the freezing edge driven by the temperature gradient, where they accumulate, leading to a decrease in the unsaturated pore space and a decrease in the equivalent vapor content. This study’s results can provide theoretical support for frost damage prevention in unsaturated silty clay in permafrost regions. Full article

Heart failure (HF) is a leading cause of morbidity and mortality worldwide, underscoring the need for improved diagnostic, prognostic, and therapeutic strategies. Circulating microRNAs (c-miRNAs) have emerged as promising non-invasive biomarkers due to their stability, tissue specificity, and regulatory roles in cardiac pathophysiology. This review highlights the potential of c-miRNAs in enhancing HF diagnosis, risk stratification, and therapeutic monitoring, particularly when integrated with conventional biomarkers such as natriuretic peptides, galectin-3, soluble ST2, and high-sensitivity troponins. We explore the roles of key miRNAs in HF pathogenesis—including cardiac hypertrophy, fibrosis, inflammation, apoptosis, and vascular remodeling—and discuss their diagnostic and prognostic significance. The potential of multi-analyte liquid biopsy approaches that combine c-miRNAs with protein biomarkers is also examined within the context of precision medicine. Despite promising data, challenges related to standardization, assay variability, and clinical validation remain. Addressing these gaps through harmonized protocols and large-scale studies will be essential for translating c-miRNAs into routine HF management. Full article

I show here that if we construct D-branes not in the form of infinite superpositions of string modes, in order to satisfy the technical condition of coherence by means of eigenstates of annihilation operators, but instead insist on an approximate but much more physical and practical definition based on phase coherence, we obtain finite (and hence realistic) superpositions of string modes that would form realistic D-branes that would encode (at least as a semiclassical approximation) various quantum properties. Re-deriving the AdS/CFT duality by starting in the pre-Maldacena limit from such realistic D-branes would lead to quantum properties on the AdS side of the duality. Causal structures can be modified in various many-particle systems, including strings, D-branes, photons, or spins; however, there is a distinction between the emergence of an effective causal structure in the inner degrees of freedom of a material, in the form of a correlation-generated effective metric, for example, in a spin liquid system, and the emergence of a causal structure in an open propagating system by using classical light. I will show how an Uhlmann gauge construction would add stability to a modified causal structure that would retain the shape of a closed causal loop. Various other ideas related to the quantum origin of the string length are also discussed and an analogy of the emergence of string length from quantum correlations with the emergence of wavelength of an electromagnetic wave from coherence conditions of photon modes is presented. Full article

Benzene, a well-established human carcinogen and major industrial pollutant, poses significant health risks through occupational exposure due to its no-threshold effect, leading to multi-system damage involving the hematopoietic, nervous, and immune systems. This makes the investigation of its toxic mechanisms crucial for precise prevention and control of its health impacts. Programmed cell death (PCD), an orderly and regulated form of cellular demise controlled by specific intracellular genes in response to various stimuli, has emerged as a key pathway where dysfunction may underlie benzene-induced toxicity. This review systematically integrates evidence linking benzene toxicity to PCD dysregulation, revealing that benzene and its metabolites induce abnormal subtypes of PCD (apoptosis, autophagy, ferroptosis) in hematopoietic cells. This occurs through mechanisms including activation of Caspase pathways, regulation of long non-coding RNAs, and epigenetic modifications, with recent research highlighting the IRP1-DHODH-ALOX12 ferroptosis axis and oxidative stress–epigenetic interactions as pivotal. Additionally, this review describes a comprehensive monitoring system for early toxic effects comprising benzene exposure biomarkers (urinary t,t-muconic acid (t,t-MA), S-phenylmercapturic acid (S-PMA)), PCD-related molecules (Caspase-3, let-7e-5p, ACSL1), oxidative stress indicators (8-OHdG), and genetic damage markers (micronuclei, p14ARF methylation), with correlative analyses between PCD mechanisms and benzene toxicity elaborated to underscore their integrative roles in risk assessment. Furthermore, the review details analytical techniques for these biomarkers, including direct benzene detection methods—direct headspace gas chromatography with flame ionization detection (DHGC-FID), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and portable headspace sampling (Portable HS)—alongside molecular imprinting and fluorescence probe technologies, as well as methodologies for toxic effect markers such as live-cell imaging, electrochemical techniques, methylation-specific PCR (MSP), and Western blotting, providing technical frameworks for mechanistic studies and translational applications. By synthesizing current evidence and mechanistic insights, this work offers novel perspectives on benzene toxicity through the PCD lens, identifies potential therapeutic targets associated with PCD dysregulation, and ultimately establishes a theoretical foundation for developing interventional strategies against benzene-induced toxicity while emphasizing the translational value of mechanistic research in occupational and environmental health. Full article

Leaves of Gentiana lutea L., traditionally used for treating heart disorders, represent a sustainable and underutilized source of bitter secoiridoids and xanthones, also found in Gentianae radix—an official herbal drug derived from the same, protected species. As root harvesting leads to the destruction of the plant, using the more readily available leaves could help reduce the pressure on this endangered natural resource. This study aimed to optimize the ultrasound-assisted extraction of the secoiridoid swertiamarin and the xanthone isogentisin from G. lutea leaves using response surface methodology (RSM). Subsequently, the stability of the bioactive compounds (swertiamarin, gentiopicrin, mangiferin, isoorientin, isovitexin, and isogentisin) in the optimized extract was monitored over a 30-day period under different storage conditions. The influence of extraction time (5–65 min), ethanol concentration (10–90% v/v), liquid-to-solid ratio (10–50 mL/g), and temperature (20–80 °C) was analyzed at five levels according to a central composite design. The calculated optimal extraction conditions for the simultaneous maximization of swertiamarin and isogentisin yields were 50 min extraction time, 30% v/v ethanol concentration, 30 mL/g liquid-to-solid ratio, and 62.7 °C extraction temperature. Under these conditions, the experimentally obtained yields were 3.75 mg/g dry weight for swertiamarin and 1.57 mg/g dry weight for isogentisin, closely matching the RSM model predictions. The stability study revealed that low-temperature storage preserved major bioactive compounds, whereas mangiferin stability was compromised by elevated temperature and light exposure. The established models support the production of standardized G. lutea leaf extracts and may facilitate the efficient separation and purification of their bioactive compounds, thereby contributing to the further valorization of this valuable plant material. Full article

Particulate matter (PM), a complex mixture of solid particles and liquid droplets, originates from both natural sources, such as sand, pollen, and marine salts, and anthropogenic activities, including vehicle emissions and industrial processes. While PM itself is not inherently toxic in all its forms, it often acts as a carrier of xenobiotic toxicants, such as heavy metals and organic pollutants, which adhere to its surface. This combination can result in synergistic toxic effects, significantly enhancing the potential harm to biological systems. Due to its small size and composition, PM can penetrate deep into the respiratory tract, acting as a physical “shuttle” that facilitates the distribution and bioavailability of toxic substances to distant organs. The omnipresence of PM in the environment leads to unavoidable and constant exposure, contributing to increased morbidity and mortality rates, particularly among vulnerable populations like the elderly, children, and individuals with pre-existing health conditions. This exposure also imposes a substantial financial burden on healthcare systems, as treating PM-related illnesses requires significant medical resources and leads to higher healthcare costs. Addressing these challenges necessitates effective mitigation strategies, including reducing PM exposure, improving air quality, and exploring novel approaches such as AI-based exposure prediction and nutritional interventions to protect public health and minimize the adverse effects of PM pollution. Full article