Search Results (741)

The lung is increasingly recognized as an organ with dual endocrine and respiratory roles, participating in a complex bidirectional crosstalk with systemic hormones and local/paracrine activity. Endocrine and paracrine pathways regulate lung development, ventilation, immunity, and repair, while pulmonary cells express hormone receptors and secrete mediators with both local and systemic effects, defining the concept of the “endocrine lung”. This narrative review summarizes current evidence on the endocrine–pulmonary axis. Thyroid hormones, glucocorticoids, sex steroids, and metabolic hormones (e.g., insulin, leptin, adiponectin) critically influence alveologenesis, surfactant production, ventilatory drive, airway mechanics, and immune responses. Conversely, the lung produces mediators such as serotonin, calcitonin gene-related peptide, endothelin-1, leptin, and keratinocyte growth factor, which regulate vascular tone, alveolar homeostasis, and immune modulation. We also describe the respiratory manifestations of major endocrine diseases, including obstructive sleep apnea and lung volume alterations in acromegaly, immunosuppression and myopathy in Cushing’s syndrome, hypoventilation in hypothyroidism, restrictive “diabetic lung”, and obesity-related phenotypes. In parallel, chronic pulmonary diseases such as chronic obstructive pulmonary disease, interstitial lung disease, and sleep apnea profoundly affect endocrine axes, promoting insulin resistance, hypogonadism, GH/IGF-1 suppression, and bone metabolism alterations. Pulmonary neuroendocrine tumors further highlight the interface, frequently presenting with paraneoplastic endocrine syndromes. Finally, therapeutic interactions are discussed, including the risks of hypothalamic–pituitary–adrenal axis suppression with inhaled corticosteroids, immunotherapy-induced endocrinopathies, and inhaled insulin. Future perspectives emphasize mapping pulmonary hormone networks, endocrine phenotyping of chronic respiratory diseases, and developing hormone-based interventions. Full article

Low-Salinity Water Flooding (LSWF) has gained attention for its cost-effectiveness and environmental advantages, yet its underlying mechanisms remain not fully understood. Oil recovery in LSWF is primarily governed by interfacial dynamics and formation wettability. This research investigates the effects of seawater dilution in carbonate reservoirs through laboratory analyses and displacement experiments. Results show that oil recovery efficiency is largely driven by rock–fluid interactions rather than fluid–fluid interactions, with optimal brine concentrations enhancing wettability alteration, boundary flexibility, and mineral leaching. These findings highlight the importance of considering both fluid–rock interactions and mineral reactivity, rather than attributing recovery to a single mechanism. Molecular dynamics simulations further supported the experimental observations. Overall, the study emphasizes that early and well-designed low-salinity injection strategies can maximize LSWF performance. The results elucidate the key interaction mechanisms between surfactants and the various components of heavy oil through atomic-scale precision modeling and dynamic process tracking. These simulations clarify, at the microscopic level, the differences in displacement dynamics and efficiency of organic solvent systems toward different hydrocarbon components. Full article

Background/Objectives: Polybia-MP1 (MP1) exhibits antimicrobial and anticancer properties. To improve selectivity toward acidic tumor microenvironments, we designed HMP1, a histidine-substituted analog of MP1, aiming to introduce pH-responsive behavior within physiological and pathological pH ranges. Methods: HMP1 was synthesized by replacing all lysine residues in MP1 with histidines. We characterized its surfactant properties and interactions with lipid monolayers composed of DPPC under varying pH and ionic strength conditions. Langmuir monolayer experiments were used to evaluate peptide-induced morphological changes and lipid packing effects at physiologically relevant lateral pressures. Results: HMP1 displayed pH-dependent activity between pH 5.5 and 7.5, inducing significant morphological reorganization of lipid domains without reducing the condensed phase area. Ionic strength modulated these effects, with distinct behaviors observed at low and physiological saline conditions. HMP1 preferentially interacted with cholesterol-enriched membranes, while MP1 did not induce comparable effects under the same conditions, as previously reported, at physiological lateral pressures. HMP1 also exhibited non-hemolytic properties and lower cytotoxicity compared to MP1. Conclusions: The lysine-to-histidine substitution conferred pH sensitivity to HMP1, enabling selective modulation of membrane organization based on lipid composition, packing, pH, and ionic environment. These findings highlight HMP1’s potential in targeted therapeutics and pH-responsive drug delivery systems. Full article

The effects of polymer concentration on rheology, surface tension, and electrical conductivity of polymer–surfactant mixtures are investigated experimentally. The polymer studied is a cationic quaternary ammonium salt of hydroxyethyl cellulose, and the surfactant used is anionic sodium lauryl sulfate. The polymer concentration is varied from 1000 to 4000 ppm, and the surfactant concentration varied from 0 to 500 ppm. Polymer concentration affects the properties of the mixtures substantially. At a given surfactant concentration, the consistency of the polymer–surfactant mixture rises sharply with the increase in polymer concentration. The mixture also becomes more shear-thinning with the increase in polymer concentration. The surface tension decreases substantially, and the electrical conductivity increases with the increase in polymer concentration at a fixed surfactant concentration. At a given polymer concentration, the consistency index generally exhibits a maximum and the surface tension exhibits a minimum at some intermediate surfactant concentration. With the increase in polymer concentration, the maximum in the consistency index and the minimum in surface tension shift to higher surfactant concentrations. Although the exact mechanisms are not clear at present, a possible explanation for the observed initial changes in rheological and surface-active properties of polymer–surfactant mixtures with the addition of surfactant is charge neutralization and entanglement of polymer chains. At high surfactant concentrations, recharging and disentanglement of polymer chains probably take place. Full article

The persistent pharmaceutical diclofenac (DCF) presents a significant environmental challenge due to its widespread presence and biological activity in water systems. This study aimed to develop and characterize a novel, low-cost biosorbent by modifying waste guava seeds (GS) with the cationic surfactant cetyltrimethylammonium bromide (CTAB) to enhance the removal of DCF from aqueous solutions. GS and seeds modified with CTAB at 2 mmol/L (MGS-2) and 10 mmol/L (MGS-10) were prepared and characterized using FTIR, SEM-EDS, TGA, and Zeta Potential measurements. Batch adsorption experiments were conducted to assess the effects of contact time, biosorbent dosage, and solution pH. CTAB modification changed the biosorbent’s surface charge from negative to positive, thereby enhancing DCF removal. The MGS-10 biosorbent demonstrated the fastest kinetics. Critically, an intermediate level of surfactant modification (MGS-2) proved optimal, achieving a maximum adsorption capacity of 38.0 mg/g at 45 °C. This capacity significantly surpassed both the GS (29.7 mg/g) and the MGS-10 (32.7 mg/g). This superior performance is attributed to a favorable multi-stage adsorption mechanism, which combines electrostatic attraction and hydrophobic interactions, and is determined to be an endothermic and entropy-driven process. While highly effective, the biosorbents showed poor regenerability with NaOH, indicating a need to explore alternative regeneration methods. This work demonstrates that optimally modified guava seeds are a promising and sustainable material for remediating pharmaceutical contaminants from water. Full article

The enhancement of drug delivery into the lung surfactant is facilitated by research on the interaction between drugs and the lung surfactant. Drug designers must have a thorough theoretical understanding of a drug before performing clinical tests to reduce the experimental cost. The current study uses a coarse-grained molecular dynamics (MD) approach with the MARTINI force field to parameterize the corticosteroid drug mometasone furoate, which is used to treat lung inflammation. Here, we investigate the accurate parametrization of drug molecules and validate the parameters with the help of umbrella sampling simulations. A collection of thermodynamic parameters was studied during the parametrization procedure. The Gibbs free energy gradient was used to calculate the partition coefficient value of mometasone furoate, which was approximately 10.49 based on our umbrella sampling simulation. The value was then matched with the experimental and predicted the partition coefficient of the drug, showing good agreement. The drug molecule was then delivered into the lung surfactant monolayer membrane at the alveolar air–water interface, resulting a concentration-dependent drop in surface tension while controlling the underlying continual compression–expansion of alveoli that maintains the exhalation–inhalation respiratory cycle. The dynamical properties of the monolayer demonstrate that the drug’s capacity to diffuse into the monolayer is considerably diminished in larger clusters, and this effect is intensified when there are more drug molecules present in the monolayer. The monolayer microstructure analysis shows that the drug concentration controls monolayer morphology. The results of this investigation may be helpful for corticosteroid drug delivery into the lung alveoli, which can be applied to comprehend how the drug interacts with lung surfactant monolayers or bilayers. Full article

This work introduces the Reverse Steam Rising Process (RSRP), a novel dissolution method, for the preparation of highly homogeneous organo-nickel composites. This approach enables gradual material dissolution, resulting in improved material integration. We investigate two distinct synthetic pathways: a direct organic material–nickel composite and a surfactant-assisted variation. Our findings demonstrate that the inclusion of a surfactant significantly improves the properties of the resulting organo-nickel composite. The RSRP method differs from traditional synthesis methods in that it utilizes reverse steam condensation to create a highly porous, multi-level structure. This unique structure significantly boosts the material’s electrocatalytic performance, particularly for the oxygen evolution reaction (OER). The Ni-MOF-CTAB catalyst exhibits an overpotential of 397 mV at 10 mA cm⁻² and a Tafel slope of 183 mV dec⁻¹, outperforming pristine Ni-MOF. The hierarchical design promotes superior ion and gas transport, while the distinctive organometallic configuration optimizes electronic interactions critical for OER activity. This innovative process enables precise control over both the micro- and nanoscale morphology of the nickel-based catalyst, ultimately leading to superior performance metrics. This advancement offers a new pathway for developing high-performance nickel organometallic materials for diverse electrocatalytic applications. Full article

Steady-shear rheology and surface activity of surfactant–polymer solutions were investigated experimentally. Four different polymers were studied as follows: cationic hydroxyethyl cellulose, nonionic hydroxyethyl cellulose, nonionic guar gum, and anionic xanthan gum. The influence of the following four surfactants on each of the polymers was determined: nonionic alcohol ethoxylate, anionic sodium lauryl sulfate, cationic hexadecyltrimethylammonium bromide, and zwitterionic cetyl betaine. The interaction between cationic hydroxyethyl cellulose and anionic sodium lauryl sulfate was extraordinarily strong, resulting in dramatic changes in rheological and surface-active properties. The consistency increased initially, reached a maximum value, and then fell off with the further addition of surfactant. The surface tension of surfactant–polymer solution dropped substantially and exhibited a minimum value. Thus, the surfactant–polymer solutions were much more surface-active compared with pure surfactant solutions. The interaction between anionic xanthan gum and cationic hexadecyltrimethylammonium bromide was also strong, resulting in a substantial decrease in consistency. The surfactant–polymer solution became less surface-active compared with pure surfactant solution due to the migration of surfactant from solution to polymer. The interactions between other polymers and surfactants were weak to moderate, resulting in small to modest changes in rheological and surface-active properties. Surface activity of surfactant–polymer solutions often increased due to the formation of complexes more surface-active than pure surfactant molecules. Full article

Surfactants demonstrate considerable potential in enzymatic saccharification at high solids loading (ESHSL). In this paper, the effects of the non-ionic surfactant Tween 80 on enzymatic saccharification of Avicel and steam-exploded poplar (SEP) at high solid loading were studied. The results showed that under the fed-batch conditions of 15.0% solid loading, 20 FPU/g glucan, and 1.0% Tween 80, the maximum enzymatic saccharification rate of Avicel and SEP achieved was 65.4% (128.2 g/L glucose) and 86.4% (93.9 g/L glucose), respectively. Moreover, Tween 80 improved the rheological properties of ESHSL slurry of SEP, especially for the fed-batch model, reducing the complex viscosity, shear stress, and storage modulus. Furthermore, cellulase adsorption assays, SDS-PAGE, Rose Bengal staining, and Zeta potential analysis demonstrated that Tween 80 reduced non-productive adsorption of cellulase (particularly β-glucosidase) on lignin through hydrophobic interactions. All these findings contribute to establishing a foundation for subsequent investigative efforts within the discipline. Full article

The interfacial and foam properties of proteins can be enhanced by altering the interactions between polyphenols and proteins. The aim of this study was to determine the influence of gallic acid (GA) on the structural properties of whey protein isolate (WPI), specifically focusing on particle size, potential, and surface hydrophobicity, as well as the subsequent alterations in its interfacial and foam properties when utilized as a foaming agent. An increase in turbidity and a decrease in particle size suggested the formation of a soluble complex between GA and WPI at a pH of 6. The results from fluorescence spectroscopy and surface hydrophobicity analyses indicated that the primary interactions between GA and WPI are characterized by hydrogen bonding and hydrophobic interactions. The reduction in particle size enhances the capacity of WPI/GA complexes to lower the surface pressure, thereby demonstrating significant efficacy at the macroscopic scale. Furthermore, the structural connectivity of GA facilitates the formation of a stable interfacial film at the air–water interface by WPI/GA, resulting in high foam stability at a macroscopic level. This research contributes to a deeper understanding of the application of protein–polyphenol complexes as surfactants and provides theoretical support for their use in food applications. Full article

This study examines the toxicological effects of carbon nanotubes (CNTs) of different diameters—single-walled CNTs (SWCNT, 2 nm) and multi-walled CNTs (MWCNT, 74 nm)—on two macrophage cell lines, rat alveolar NR8383 cells and human differentiated THP-1. Using standardized exposure conditions and employing an integrated omics approach (transcriptomic and proteomic analyses), both CNT types were found to induce cellular stress responses and inflammation, especially in NR8383 cells, with notable involvement of the Sirtuin signaling pathway. After 24 h, MWCNTs uniquely disrupted lipid metabolism in NR8383 cells, resulting in foam cell formation and syncytia. While SWCNTs were less disruptive to metabolic pathways, they significantly altered gene regulation, particularly RNA splicing mechanisms. The dispersion medium—fetal bovine serum (FBS) versus human surfactant—also modulated the observed toxicological responses, highlighting the critical role of the protein corona in influencing CNT-cell interactions. These findings demonstrate that CNT diameter significantly affects cytotoxicity and cellular response pathways in a cell-type-specific manner. Full article

Salmonella enterica subsp. enterica serovar Typhimurium is a major foodborne pathogen whose ability to form biofilms contributes to persistent contamination in food-processing and clinical environments. This study investigated the anti-biofilm activity of the biosurfactant surfactin, produced by Bacillus subtilis, against S. Typhimurium wild type (LT2) and its lipopolysaccharide (LPS)-modified mutants on commonly used plastic surfaces such as polypropylene (PP) and polystyrene (PS). Biofilm formation was quantified using the crystal violet assay, revealing significantly higher biomass on PS compared to PP (p < 0.0001). Surfactin at 5 µg/mL was identified as the minimum biofilm inhibitory concentration (MBIC), significantly reducing biofilm formation in the wild-type and LPS mutants rfaL, rfaJ, rfaF (all p < 0.0001), and rfaI (p < 0.01). Further analysis using fluorescence microscopy and SYPRO^® Ruby staining confirmed a significant reduction in extracellular polymeric substances (EPSs) on PP surfaces following surfactin treatment, particularly in strains LT2 (p < 0.0001), rfa (p < 0.01), rfaL (p < 0.0001), rfaG (p < 0.05), and rfaE (p < 0.0001). These findings highlight the influence of LPS structure on biofilm development and demonstrate surfactin’s potential as an eco-friendly antimicrobial agent for controlling S. Typhimurium biofilms on food-contact surfaces. Analysis of mutants revealed that disruption of the rfa gene, which is involved in the biosynthesis of the outermost region of the lipopolysaccharide (LPS), significantly reduced bacterial attachment to polypropylene. This suggests that interactions between the external LPS layer and the plastic surface are important for colonisation. In contrast, mutants in core LPS biosynthesis genes such as rfaE and rfaD did not show any notable differences in attachment compared to the wild-type strain. This highlights the specific importance of outer LPS components, particularly under surfactant conditions, in mediating interactions with plastic surfaces. This work supports the application of biosurfactants in food safety strategies to reduce the risk of biofilm-associated contamination. Full article

Sophorolipids (SLs) constitute a group of unique biosurfactants in light of their unique properties, among which their physicochemical characteristics and antimicrobial activity stand out. SLs can exist mainly in acidic and lactonic forms, both of which display inhibitory activity. This study explores the interaction of non-acetylated acidic SL with bovine serum albumin (BSA). SL significantly enhances BSA’s thermal stability, increasing its midpoint unfolding temperature from 61.9 °C to approximately 76.0 °C and ΔH from 727 to 1054 kJ mol⁻¹ at high concentrations, indicating cooperative binding. Fourier-Transform Infrared Spectroscopy (FTIR) analysis confirms SL’s protective effect against thermal unfolding, enabling BSA to maintain its helical structure at 70 °C, distinguishing it from other surfactants that cause denaturation. Furthermore, SL fundamentally alters the sequence of thermal unfolding events; β-aggregation precedes helical domain unfolding, suggesting protective binding to BSA’s helical regions. Computational docking reveals high-affinity binding (Kd = 14.5 μM). Uniquely, SL binds between BSA domains IB and IIIA, establishing hydrophobic interactions, salt bridges, and hydrogen bonds, thus stabilizing the protein’s 3D structure. This distinct binding site is attributed to SL’s amphipathic character. This work deepens the understanding of the molecular characteristics of SL–protein interactions and contributes to improving the general knowledge of this outstanding biosurfactant. Full article

In the mining industry, key unit operations such as grinding, flotation, thickening, and tailings transport are negatively affected by the presence of clay minerals, which impart complex rheological behaviors to mineral suspensions by increasing their rheological properties. This deterioration arises from specific physicochemical characteristics of clay minerals such as fine particle size, anisotropic character, laminar morphology, and swelling capacity. This work reviews the effects of various rheology-modifying reagents on clay suspensions including kaolinite, illite, and montmorillonite. The reviewed reagents include inorganic salts, pH modifiers, polymers, surfactants, and nanoparticles. Their mechanisms of interaction with solid particles are analyzed, highlighting their influence on the degree of dispersion or aggregation. Furthermore, this review proposes research opportunities focused on the formulation of hybrid reagents, modified biopolymers, and the development of reagents effective under adverse conditions such as high salinity or elevated temperatures. This review provides a comprehensive basis for optimizing the use of rheological additives through more efficient and sustainable strategies for managing clay-rich suspensions in the mining industry. Full article

Hyaluronic acid and carboxymethyl cellulose are eco-friendly polysaccharides known for their excellent moisture retention properties, making them suitable components of agricultural fertilizers. On the other hand, humic acids exhibit surface-active properties, suggesting their potential to replace synthetic surfactants in agricultural applications. Naturally, the interaction between polysaccharides and humic substances influences their colloidal and chemical behavior. The mutual interactions between humic acids and these polysaccharides were examined at immiscible liquid interfaces and on plant leaf surfaces using radiotracer analysis and tensiometry (pendant drop and sessile drop methods). The results indicate that humic acids achieve optimal adsorption at a hyaluronic acid concentration of 30 g/L, regardless of molecular weight. In contrast, carboxymethyl cellulose reduces the surface activity of humic acids. Additionally, a combined solution of humic acids and hyaluronic acid improves the wetting efficiency of wheat leaves compared to individual solutions. However, humic acids showed minimal impact on the absorption or systemic distribution of hyaluronic acid within the plant. Full article