Search Results (90)

Reactive nitrogen species (RNS), particularly peroxynitrite (ONOO⁻), play a central role in post-translational modifications (PTMs) of proteins, including fibrinogen, a key component of the coagulation cascade. This review explores the structural and functional consequences of fibrinogen nitration, with a focus on its impact on clot formation, morphology, mechanical stability, and fibrinolysis. Nitration, primarily targeting tyrosine residues within functional domains of the Aα, Bβ, and γ chains, induces conformational changes, dityrosine crosslinking, and aggregation into high molecular weight species. These modifications result in altered fibrin polymerization, the formation of porous and disorganized clot networks, reduced mechanical resilience, and variable susceptibility to fibrinolysis. Moreover, nitrated fibrinogen may affect interactions with platelets and endothelial cells, although current evidence remains limited. Emerging clinical studies support its role as both a prothrombotic mediator and a potential biomarker of oxidative stress in cardiovascular and inflammatory diseases. Finally, we explore both pharmacological interventions, such as NOX inhibitors, and natural antioxidant strategies at counteracting fibrinogen nitration. Overall, fibrinogen nitration emerges as a critical molecular event linking oxidative stress to thrombotic risk. Full article

Delivering of hydrophobic drugs by polymeric nanoparticles is an intensively investigated research and development field worldwide due to the insufficient solubility of many existing and potential new drugs in aqueous media. Among polymeric nanoparticles, micelles of biocompatible amphiphilic block copolymers are among the most promising candidates for solubilization, encapsulation, and delivery of hydrophobic drugs to improve the water solubility and thus the bioavailability of such drugs. In this study, amphiphilic ABA triblock copolymers containing biocompatible hydrophilic hyperbranched (dendritic) polyglycerol (HbPG) outer and hydrophobic poly(tetrahydrofuran) (PTHF) inner segments were synthesized using amine-telechelic PTHF as a macroinitiator for glycidol polymerization. These hyperbranched–linear–hyperbranched block copolymers form nanosized micelles with 15–20 nm diameter above the critical micelle concentration. Coagulation experiments proved high colloidal stability of the aqueous micellar solutions of these block copolymers against temperature changes. The applicability of block copolymers as drug delivery systems was investigated using curcumin, a highly hydrophobic, water-insoluble, natural anti-cancer agent. High and efficient drug solubilization up to more than 3 orders of magnitude to that of the water solubility of curcumin (>1500-fold) is achieved with the HbPG-PTHF-HbPG block copolymer nanomicelles, locating the drug in amorphous form in the inner PTHF core. Outstanding stability of and sustained curcumin release from the drug-loaded block copolymer micelles were observed. The in vitro bioactivity of the curcumin-loaded nanomicelles was investigated on U-87 glioblastoma cell line, and an optimal triblock copolymer composition was found, which showed highly effective cellular uptake and no toxicity. These findings indicate that the HbPG-PTHF-HbPG triblock copolymers are promising candidates for advanced drug solubilization and delivery systems. Full article

Naturally occurring plant-based compounds are increasingly being explored for their therapeutic potential in treating a wide range of conditions, particularly those related to vascular health. The compound 3-deoxysappanchalcone (3-DSC), derived from Caesalpinia sappan L., has been proven to exhibit anti-inflammatory, anti-influenza, and anti-allergic properties, though its role in thrombosis and haemostasis remains unexplored. This study aimed to evaluate the anti-thrombotic potential of 3-DSC in both in vitro and in vivo models. The anticoagulant activities of 3-DSC were assessed using activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin (FIIa) and activated factor X (FXa) activity assays, as well as fibrin polymerization and platelet aggregation tests. Its effects on plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) expression were evaluated in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs). The results demonstrated that 3-DSC extended aPTT and PT, suppressed thrombin and FXa activities, reduced their production in HUVECs, inhibited thrombin-induced fibrin polymerization and platelet aggregation, and exerted anticoagulant effects in mice. Furthermore, 3-DSC significantly decreased the PAI-1 to t-PA ratio. These findings suggest that 3-DSC possesses potent anti-thrombotic properties by modulating coagulation pathways and fibrinolysis. Its therapeutic potential warrants further investigation for the development of novel anticoagulant agents. Full article

In this study, the treatment of pharmaceutical tail water (PTW) by coagulation, Fenton combined with membrane bioreactor (MBR), was studied. Optimal parameters were obtained according to batch experiment and central composite design (CCD). Results showed that Polymeric Ferric Sulfate (PFS) was the best coagulant for original pharmaceutical tailwater due to less dosage and higher removal efficiency to TOC, COD, NH₄⁺-N and UV_254m, with the optimized pH = 7.25 and 0.53 g/L PFS dosage. The best coagulation performance was achieved when the mixer was stirred at 250 rpm for 3 min, 60 rpm for 10 min, and then left to stand for 60 min. Coagulation mainly removed organics with molecular weight above 10 kDa. After treated by coagulation, 43.1% TOC removal efficiency of PTW was obtained by Fenton reaction with 11.6 mmol/L H₂O₂, 3.0 mmol/L FeSO₄, pH = 3.3 and T = 50 min. A type of common macromolecule aromatic amino acid compounds which located Ex = 250 nm and Em = 500 nm was the main reason that caused the high TOC concentration in the effluent. Stable COD and NH₄⁺-N removal efficiencies in the MBR reactor within 10 d were observed when the mixture of pre-treated PTW (20%, v) and domestic sewage (80%, v) was fed into the MBR reactor, and over 95% COD and 50% NH₄⁺-N were removed. One kind of amino acid similar to tryptophan was the prime reason that caused PTW resistance to be degraded. Analysis of the microorganism community in the MBR suggested that norank_f__Saprospiraceae was the key microorganism in degrading of PTW. Full article

Homocysteinylation, a post-translational modification involving the covalent attachment of homocysteine to proteins, has emerged as a critical mechanism linking hyperhomocysteinemia to thrombotic disease. This review focuses on the homocysteinylation of fibrinogen, a key coagulation factor, and its impact on clot structure and function. Evidence indicates that elevated homocysteine levels can induce significant changes in fibrin architecture, promoting the formation of dense, rigid clots with reduced permeability and impaired fibrinolytic susceptibility, thus fostering a prothrombotic environment. However, inconsistencies in reported effects on fiber diameter and polymerization kinetics highlight the need for standardized experimental protocols. Advances in proteomics and high-resolution imaging are expected to clarify the molecular underpinnings of these modifications. Moreover, homocysteinylation intersects with oxidative stress and may serve as a mechanistic bridge between metabolic and vascular dysfunction. Understanding its role not only enhances insight into thrombosis but also opens avenues for biomarker discovery and targeted therapies in cardiovascular and potentially neurological disorders. Full article

Phosphorus contamination in water bodies is a major contributor to eutrophication, leading to algal overgrowth, oxygen depletion, and ecological imbalance. Conventional treatment methods, including chemical precipitation and synthetic adsorbents, are often limited by high operational costs, low biodegradability, and secondary pollutant generation. In this study, a cationic starch was synthesized through free radical graft polymerization of 3-methacrylamoylaminopropyl trimethyl ammonium chloride (MAPTAC) onto corn starch. The modified polymer exhibited a high degree of substitution (DS = 1.24), indicating successful functionalization with quaternary ammonium groups. Theoretical calculations using zDensity Functional Theory (DFT) at the B3LYP/6-311+G(d,p) level revealed a decrease in chemical hardness (from 0.10442 eV to 0.04386 eV) and a lower ionization potential (from 0.24911 eV to 0.15611 eV) in the modified starch, indicating enhanced electronic reactivity. HOMO-LUMO analysis and molecular electrostatic potential (MEP) maps confirmed increased electron-accepting capacity and the formation of new electrophilic sites. Experimentally, the cationic starch showed stable zeta potential values averaging +15.3 mV across pH 5.0–10.0, outperforming aluminum sulfate (Alum), which reversed its charge above pH 7.5. In coagulation-flocculation trials, the modified starch achieved 87% total suspended solids (TSS) removal at a low coagulant-to-biomass ratio of 0.0601 (w/w) using Scenedesmus obliquus, and 78% TSS removal in real wastewater at a 1.5:1 ratio. Additionally, it removed 30% of total phosphorus (TP) under environmentally benign conditions, comparable to Alum but with lower chemical input. The integration of computational and experimental approaches demonstrates that MAPTAC-modified starch is an efficient, eco-friendly, and low-cost alternative for nutrient and solids removal in wastewater treatment. Full article

In seeking alternatives for reducing environmental damage, fabricating filtration membranes using biopolymers derived from agro-industrial residues, such as cellulose acetate (CA), partially dissolved with green solvents, represents an economical and sustainable option. However, dissolving CA in green solvents through mechanical agitation can take up to 48 h. An ultrasonic probe was proposed to accelerate mass transfer and polymer dissolution via pulsed interval cavitation. Additionally, ultrasound-assisted phase inversion (UAPI) on the external coagulation bath was assessed to determine its influence on the properties of flat sheet and hollow fiber membranes during phase inversion. Results indicated that the ultrasonic pulses reduced dissolution time by up to 98% without affecting viscosity (3.24 ± 0.06 Pa·s), thermal stability, or the rheological behavior of the polymeric blend. UAPI increased water permeability in flat sheet membranes by 26% while maintaining whey protein rejection above 90%. For hollow fiber membranes, UAPI (wavelength amplitude of 0 to 20%) improved permeability by 15.7% and reduced protein retention from 90% to 70%, with MWCO between 68 and 240 kDa. This report demonstrates the effectiveness of ultrasonic probes for decreasing the dissolution time of dope solution with green cosolvents and its potential to change the structure of polymeric membranes by ultrasound-assisted phase inversion. Full article

Rapid urbanisation and industrialisation have intensified the Urban Heat Island (UHI) effect, significantly increasing energy demand for thermal comfort. Urban buildings consume considerable energy throughout the year, which can be reduced by incorporating Phase Change Materials (PCMs) into building materials. PCMs effectively regulate temperature by storing and releasing heat as latent heat during phase transitions. However, to prevent leakage, PCMs can be encapsulated in co-axial polymeric Phase Change Fibres (PCFs), representing an innovative approach in scientific research. This study optimised the coagulation bath and produced PCFs using commercial cellulose acetate as the sheath and polyethylene glycol (PEG 600 and 1000) as the core via the wet-spinning method. The first part of this work investigated the coagulation bath using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) analyses of the characteristic peak areas. In contrast, the second part examined the PCFs’ morphological, chemical and thermal properties using Bright-field microscopy, ATR-FTIR, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) techniques. The results demonstrated the successful production of PCFs with an optimised coagulation bath. Bright-field microscopy and ATR-FTIR confirmed the well-defined morphology and the presence of PEG in the fibre core. TGA analysis showed high thermal stability in the PCFs, with mass loss observed at high degradation temperatures, ranging from ~264 °C to 397 °C for the PCFs with PEG 600 and from ~273 °C to 413 °C for the PCFs with PEG 1000. Meanwhile, DSC analysis revealed melting points of ~12.64 °C and 11.04 °C, with endothermic enthalpy of ~39.24 °C and 30.59 °C and exothermic enthalpy of ~50.17 °C and 40.93 °C, respectively, for PCFs with PEG 600, and melting points of ~40.32 °C and 41.13 °C, with endothermic enthalpy of ~83.47 °C and 98.88 °C and exothermic enthalpy of ~84.66 °C and 88.79 °C, respectively, for PCFs with PEG 1000. These results validate the potential of PCFs for applications in building materials for civil engineering, promoting thermal efficiency and structural stability. Full article

Self-healing composites are designed based on natural healing processes such as bone regeneration and blood coagulation. These composites have polymeric material containing covalent adaptable networks that rearrange their molecular structure when heated, thereby serving as a healing agent. The inclusion of the healing polymers into the principal matrix of the fiber-reinforced composites alters their off-axis properties. In addition, the healing agents tend to bleed out of the composite structures upon heating. It is, therefore, essential to characterize the extent of the changes in the off-axis properties of the self-healing composites. In this research work, three different configurations of self-healing composites are subjected to three-point bending tests, and their healing characteristics are studied using Acousto-Ultrasonic tests. Frequencies of the propagating stress waves in the AU tests are used to analyze the different conditions of the self-healing composites, such as virgin, damaged, damaged-partially healed, and damaged-fully healed. The results show that the AU test could potentially be used to evaluate the healing behavior of these fiber-reinforced self-healable composites. Full article

The superiorities provided by polymeric composite membranes in comparison to the original membrane have generated increased attention, particularly in the field of protein separation applications. This work involved the fabrication of polysulfone composite membranes using variable loadings of activated carbon particle sizes, namely, 37 µm, 74 µm, 149 µm, and 297 µm. The membranes were fabricated via the phase-inversion method, employing water as the coagulant. In this study, the impact of the AC powder particle sizes on membrane morphology, water contact angle, porosity, average pore size, molecular weight cutoff, pure water flux, and protein rejection was examined. Different membrane morphologies and properties were achieved by incorporating a variety of AC particle sizes. A porous membrane with the maximum pure water flux was generated by the loading of finer AC particles. Concurrently, protein rejection is increasing as a result of the use of AC particles as an infill in the composite membrane. In comparison to all fabricated membranes, the AC filler with a particle size of 149 µm exhibited the highest rejection of the lysozyme protein, reaching up to 73.9%, with a relatively high water permeability of 33 LMH/Bar. In conclusion, this investigation provides recommendations for the selection of AC particle sizes for protein separation in conjunction with PSF ultrafiltration membranes. Full article

In this study, the sodium perborate (SP)-activated peroxymonosulfate (PMS) process was used to enhance the coagulation efficiency of cyanobacteria with polymeric aluminum chloride (PAC), aiming to efficiently mitigate the impact of algal blooms on the safety of drinking water production. The optimal concentrations of SP, PMS, and PAC were determined by evaluating the removal rate of OD₆₈₀ and zeta potential of the algae. Experimental results demonstrated that the proposed ternary PMS/SP/PAC process achieved a remarkable OD₆₈₀ removal efficiency of 95.2%, significantly surpassing those obtained from individual treatments with PMS (19.5%), SP (5.2%), and PAC (42.1%), as well as combined treatments with PMS/PAC (55.7%) and PMS/SP (28%). The synergistic effect of PMS/SP/PAC led to the enhanced aggregation of cyanobacteria cells due to a substantial reduction in their zeta potential. Flow cytometry was performed to investigate cell integrity before and after treatment with PMS/SP/PAC. Disinfection by-products (DBPs) (sodium hypochlorite disinfection) of the algae-laden water subsequent to PMS/SP/PAC treatment declined by 57.1%. Moreover, microcystin-LR was completely degraded by PMS/SP/PAC. Electron paramagnetic resonance (EPR) analysis evidenced the continuous production of ${\mathrm{S}\mathrm{O}}_4^{•-}$, •OH, ¹O₂, and ${\mathrm{O}}_2^{•-}$, contributing to both cell destruction and organic matter degradation. This study highlighted the significant potential offered by the PMS/SP/PAC process for treating algae-laden water. Full article

This study explores the enhanced removal of refractory organic compounds from coking wastewater using polyaluminum chloride (PACl) with two different basicity levels (0.5 and 2.5), in combination with coagulant aids such as cationic polyacrylamide (CPAM) and iron ions. The results demonstrated that both PACl formulations significantly outperformed commercial PACl in terms of COD and color removal, with PACl at the basicity of 2.5 achieving slightly higher efficiency than PACl at the basicity of 0.5. The improved performance was attributed to the higher content of polymeric aluminum species, enhancing charge neutralization and bridging adsorption. The addition of coagulant aids further improved the performance, with PACl at the basicity of 2.5 combined with iron ions achieving the highest COD (48.41%) and color removal (80.77%), due to sweep coagulation and complexation. Organic composition analysis using gas chromatography–mass spectrometry (GC-MS), three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy, and ultraviolet (UV) spectroscopy indicated that PACl combined with iron ions was the most effective in removing polycyclic aromatic hydrocarbons (PAHs) and nitrogen-, oxygen-, and sulfur-containing heterocyclic compounds. Additionally, a floc analysis showed that the flocs formed with iron ions were more compact and had better settleability compared to those formed with CPAM, further contributing to the improved coagulation efficiency. These results highlight the importance of optimizing the PACl basicity and coagulant aid selection for the enhanced removal of refractory organic compounds from coking wastewater, offering a promising strategy for advanced wastewater treatment. Full article

The use of coagulants, such as ferric chloride hexahydrate, in wastewater treatment processes is known to induce pipe corrosion and to contribute to the discoloration of treated water. This study explores alternative approaches to sludge dewatering by evaluating the effectiveness of polymeric aluminum chloride (PAC) as a coagulant and polyoxyethylene alkyl ether (POAE) as a surfactant. The impacts of coagulation/flocculation were assessed using time to filtration (TTF) and a pressure filter press. The effects of certain coagulant and surfactant dosages were studied. The inputs were in the range of 105–1750 mg/L for PAC and 28–152 mg/L for POAE, which were determined based on zeta potential (ZP) measurements. The optimal concentrations were 876 mg/L for PAC and 114 mg/L for POAE, resulting in a TTF of less than 1 min. Moreover, the effect of pH on anaerobic sludge dewaterability was investigated. At a low pH below 8, the ZP reached the maximum value, and a higher pH resulted in a reduction in ZP. Under low-pH adjustments, it was observed that the dewatering performance of the POAE surfactant improved more significantly than that of the PAC coagulant. In addition, the effect of pressure was analyzed using a pressure filter under conditions favoring POAE, with relatively lower dosages and greater cost-effectiveness. In order to evaluate the solubility of organic matter under pressurized conditions, the filtrate’s removal efficiency, chemical oxygen demand (COD), and total phosphorus (TP) were investigated. Solubilization did not occur at an increased pressure of around 10 bars. The findings presented in this study provide technical assistance for sludge treatment. Full article

This work presents methods of obtaining polymeric hollow-fiber membranes produced via the dry–wet phase inversion method that were published in renowned specialized membrane publications in the years 2010–2020. Obtaining hollow-fiber membranes, unlike flat membranes, requires the use of a special installation for their production, the most important component of which is the hollow fiber forming spinneret. This method is most often used in obtaining membranes made of polysulfone, polyethersulfone, polyurethane, cellulose acetate, and its derivatives. Many factors affect the properties of the membranes obtained. By changing the parameters of the spinning process, we change the thickness of the membranes’ walls and the diameter of the hollow fibers, which causes changes in the membranes’ structure and, as a consequence, changes in their transport/separation parameters. The type of bore fluid affects the porosity of the inner epidermal layer or causes its atrophy. Porogenic compounds such as polyvinylpyrrolidones and polyethylene glycols and other substances that additionally increase the membrane porosity are often added to the polymer solution. Another example is a blend of two- or multi-component membranes and dual-layer membranes that are obtained using a three-nozzle spinneret. In dual-layer membranes, one layer is the membrane scaffolding, and the other is the separation layer. Also, the temperature during the process, the humidity, and the composition of the solution in the coagulating bath have impact on the parameters of the membranes obtained. Full article

The rheological properties, spinnability, and thermal–oxidative stabilization of high-molecular-weight linear polyacrylonitrile (PAN) homopolymers (molecular weights M_η = 90–500 kg/mol), synthesized via a novel metal-free anionic polymerization method, were investigated to reduce coagulant use, enable solvent recycling, and increase the carbon yield of the resulting carbon fibers. This approach enabled the application of the mechanotropic (non-coagulating) spinning method for homopolymer PAN solutions in a wide range of molecular weights and demonstrated the possibility of achieving a high degree of fiber orientation and reasonable mechanical properties. Rheological analysis revealed a significant increase in solution elasticity (G′) with increasing molecular weight, facilitating the choice of optimal deformation rates for effective chain stretching prior to strain-induced phase separation during the eco-friendly spinning of concentrated solutions without using coagulation baths. The possibility of collecting ~80 wt% of the solvent at the first stage of spinning from the as-spun fibers was shown. Transparent, defect-free fibers with a tensile strength of up to 800 MPa and elongation at break of about 20% were spun. Thermal treatment up to 1500 °C yielded carbon fibers with a carbon residue of ~50 wt%, in contrast to ~35 wt% for industrial radically polymerized PAN carbonized under the same conditions. Full article