Search Results (312)

Background: The ability of synthetic plastics to persist in the environment and the accumulation of microplastics has intensified the need to explore biological mechanisms capable of interacting with, and possibly degrading, polymeric materials. Microbial enzymes that have extensive catalytic flexibility represent promising candidates in this context. Aim: This study set out to examine the molecular interaction patterns and dynamical stability of Pseudomonas aeruginosa elastase (LasB) with representative structural fragments of typical synthetic plastics to assess the suitability of the enzyme to polymer-derived substrates. Methods: The crystallographic structure of LasB (PDB ID: 1EZM) was retrieved from the Protein Data Bank and pre-prepared with the help of AutoDock4.2.6 Tools. Those polymer-derived ligands that were associated with the major industrial plastics such as polyamide (PA), polyvinyl chloride (PVC), polycarbonate (PC), poly-ethylene terephthalate (PET), polymethyl methacrylate (PMMA), and polyurethane (PUR) were retrieved in the PubChem database and geometrically optimized with the help of the MMFF94 force field. AutoDock Vina, with a specific grid box around the catalytic pocket, including Zn²⁺ ion, was used to perform molecular docking simulations. PyMOL and BIOVIA Discovery Studio software were used to analyze binding conformations, interaction residues and types of intermolecular contacts. Phosphoramidon, a known metalloprotease inhibitor, served as a positive control to confirm the docking protocol. Additional assessment of the structural stability and conformational behavior of the enzyme–ligand complexes was conducted by molecular dynamics (MD) simulations with the Desmond engine and explicit solvent model in a 50 ns trajectory using the OPLS4 force field. RMSD, RMSF, radius of gyration, hydrogen bonding analysis and solvent accessibility parameters were used to measure structural stability. Results: The docking experiment showed varying binding affinities with the test polymers. Polycarbonate (−5.774 kcal/mol) and polyurethane (−5.707 kcal/mol) had the highest in-teractions with the LasB catalytic pocket, polyamide (−5.277 kcal/mol) and PET (−4.483 kcal/mol) followed PMMA and PVC, which had weaker affinities. The following were the important residues involved in interaction networks: Glu141, His140, Val137, Arg198, Tyr114, and Trp115 that were implicated in interaction networks with hydrophobic interactions, π-cation interactions and van der Waals forces that were the major stabilization forces. MD simulations had stabilized complexes, and RMSD values were found to be within acceptable ranges of stability, and ligand-specific changes (around 1.0-3.2 A), which is also in line with stable protein-ligand systems. Phosphoramidon used as a positive control had an RMSD of 1.205 A which is within this stability range. PCA determined various ligand-bound conformational states of LasB with PA in com-pact state, PC and PVC in intermediate states and PUR, PMMA and PET in ex-panded conformations, indicating structur-al stability and adaptability of the binding pocket. Conclusion: These findings show that LasB has a structurally flexible catalytic pocket that can accommodate a wide range of polymer-derived ligands. These results offer an insight into the recognition of enzymes with polymers at the molecular level and also indicate that LasB might help in the interaction of microorganisms with synthetic plastics in environmental systems. Full article

Background/Objectives: Inclusion complexes among drugs and cyclodextrin-modified polymers are a topic of recent interest in pharmaceutical research and industry as they might expand the solubility, bioavailability, and stability of the guest molecules. Polyurethanes derived from cyclodextrins show some biomedical applications. In this study, two cross-linked polyurethane networks based on hydroxypropyl-β-cyclodextrin (HPβCD) and polyethylene glycols (PEG 2000 or PEG 6000) were synthesized with NCO/OH molar ratio 4.3 and 6.3 by the typical two-step polymerization method. Methods: Inclusion complexes of clotrimazole (CLOT) with two HPβCD-modified polyurethane networks and their corresponding physical mixtures were prepared using kneading methods and physical mixing in a 1:6 weight ratio of CLOT:HPβCD. Results: Obtained prepolymers, previously end-capped with isocyanate groups forming urethane links with HPβCD, which were confirmed by FTIR analysis. TGA results indicate a slight increase in thermal stability of the prepared complexes. The characteristic endothermic peak of the CLOT at around 145.90 °C did not appear in the DSC curve of the drug-loaded inclusion complexes. The XRD patterns of physical mixtures showed specific peaks corresponding to pure clotrimazole. SEM micrographs confirmed an elliptical/spherical- and plate-shaped particles without phase segregation, indirectly confirming that CLOT is not separately present due to inclusion into HPβCD and entrapment into polyurethane networks. Novel complexes PUR2/HPβCD-CLOT-IC and PUR3/HPβCD-CLOT-IC were applied as drug carriers, and diffusion-controlled kinetics of CLOT release were best described using Higuchi model. Conclusions: The obtained in vitro results showed surprisingly slow/prolonged clotrimazole release from modified polyurethane networks due to the significant influence of NCO/OH molar ratio and the chosen polyol soft segments chain length with potential in vivo applications. Full article

Bacterial pathogens secrete effector proteins that suppress plant immune responses and facilitate infection. This study focuses on Pectobacterium brasiliense NJAU180, a bacterial pathogen causing severe blackleg disease in potato plants in Inner Mongolia, China. Using exoproteomic analysis, plant-induced extracellular proteins were identified by comparing culture supernatants from P. brasiliense NJAU180 grown in minimal medium (MM) alone and in the presence of aseptically grown potato plantlets at an early growth stage (OD₆₀₀ ≈ 0.5). The results reveal PurK as a novel plant-induced extracellular protein, and deletion of purK markedly reduces virulence. PurK, N⁵-carboxyaminoimidazole ribonucleotide synthetase, is a key enzyme in de novo purine biosynthesis. Its impact on virulence is distinct from the conventional production of plant cell wall–degrading enzymes: PurK promotes motility by modulating transcription of flagellar genes, acting through its three domains as an integrated unit to infect successfully. Extracellularly detected PurK suppresses callose deposition, a PAMP-triggered immunity (PTI)-like defense, while it also triggers a strong hypersensitive response and upregulates expression of PTI marker genes such as PR2 and WRKY7 when secreted into the host plant. Although PurK interacts specifically with PurE, our data indicate that PurK’s pathogenic effects operate independently of purine biosynthesis. This study reveals a reliable experimental model for more accurate assessment of microbe–plant interactions and highlights new functional roles for PurK in P. brasiliense NJAU180 pathogenesis and identifies potential targets for disease control strategies. Full article

Polymer-based insulation materials are widely used to enhance the energy efficiency of buildings; however, their growing application raises concerns related to resource use and end-of-life management. Rigid polyurethane (PUR) foams are key core materials in structural insulated panels due to their favorable thermal and mechanical performance, yet their life cycle environmental impacts—particularly at end-of-life—remain insufficiently quantified. In this study, a cradle-to-grave life cycle assessment (LCA) of PUR-based insulation used in structural insulated panel systems is conducted in accordance with ISO 14040/44 and EN 15804 standards. The assessment is performed using Sphera LCA software (version: GaBi 10.5) and the CML 2016 impact assessment method. Formulation-level variations in rigid PUR foams, including changes in methylene diphenyl diisocyanate content and pentane blowing agent ratio, are explicitly incorporated to evaluate their influence on key environmental impact categories. The results indicate that increasing pentane content leads to higher global warming potential, while this effect may be mitigated or intensified by concurrent changes in diisocyanate content and foam density in fully formulated systems. Three end-of-life scenarios—landfilling, incineration with energy recovery, and mechanical recycling—are analyzed. The findings provide material-level, decision-relevant insights that support environmentally informed formulation strategies and contribute to the development of more circular polymer-based insulation solutions for the built environment. Full article

The oxidation of flexible polyurethane (PUR) foams significantly impacts product durability, vehicle indoor air quality, and volatile organic compound (VOC) emissions. This study investigates oxidation kinetics and VOC emissions (65–155 °C) from foams with indices between 70 and 115 (molar ratio of NCO to NCO-reactive groups × 100), where a higher index represents greater hard segment (methylene diphenyl diisocyanate) and lower soft segment (polyether polyol) content. Using a flow-through setup with PTFE chambers and Tenax thermodesorption tubes and dinitrophenylhydrazine (DNPH) cartridges, VOCs from initial analyte loading, hydroperoxide degradation, and autoxidation were distinguished, providing robust kinetic data unaffected by diffusion interference. A higher index accelerated soft segment degradation, increasing oxidation rates and VOC emissions. The activation energy of 1,2-propanediol-1-acetate-2-formate increased from 87 kJ/mol in low-index to 108 kJ/mol in high-index formulations. VOC emissions from high-index foams were tripled for acetaldehyde during long-term aging at 65 °C. While most emissions followed Arrhenius behavior, formaldehyde and acrolein deviated above 100 °C, with higher hard-segment content extending their Arrhenius range. These findings link PUR composition to degradation behavior and emissions, enabling formulation improvements. The results advance methods for evaluating raw material contributions and the performance of antioxidants under realistic aging conditions. Full article

Trigeminal neuralgia and orofacial pain often require effective local anesthesia with minimal side effects. Puerarin (PUE), a major bioactive flavonoid derived from Pueraria lobata, has shown potential analgesic properties. This study aimed to investigate the inhibitory effects of local PUE administration on the excitability of wide-dynamic-range (WDR) neurons in the spinal trigeminal nucleus caudalis (SpVc) and to compare its potency with the conventional local anesthetic lidocaine. Extracellular single-unit recordings were performed on SpVc WDR neurons in anesthetized rats. PUE (1 and 10 mM) or lidocaine (37 mM; 1%) was administered subcutaneously into the peripheral receptive field. Neuronal responses to graded non-noxious and noxious mechanical stimuli were quantified before and after drug application. Local administration of PUE significantly suppressed the mean firing frequency of SpVc WDR neurons in a dose-dependent and reversible manner. The inhibitory effect peaked at 10 min post-injection and recovered within 30 min. Notably, 10 mM PUE exerted an inhibitory magnitude (68.7 ± 6.4%) comparable to that of 37 mM lidocaine (58.1 ± 4.3%), indicating that PUE possesses approximately four-fold the inhibitory potency of lidocaine on a molar basis. The suppressive effect was consistent across both non-noxious and noxious stimulus intensities. These findings provide the first in vivo evidence that PUE effectively attenuates trigeminal nociceptive transmission, likely via the modulation of voltage-gated sodium channels and acid-sensing ionic channels at peripheral nerve terminals. As a natural dietary constituent with high potency and a low risk of systemic side effects, PUR represents a promising candidate for complementary and alternative medicine in the management of orofacial pain, such as temporomandibular disorders and trigeminal neuralgia. Full article

The modified DNA base 2,6 aminopurine (2-aminoadenine, (d)Z base) was originally found in phages to counteract host-encoded restriction systems. However, only a limited number of restriction endonucleases (REases) have been tested on dZ-modified DNA. Here, we report the activity results of 147 REases on dZ-modified PCR DNA. Among the enzymes tested, 53% are resistant or partially resistant, and 47% are sensitive when their restriction sites contain one to six modified bases. Sites with four to six dZ substitutions are most likely to resist Type II restriction. Our results support the notion that dZ-modified phage genomes evolved to combat host-encoded restriction systems. dZ-modified DNA can also reduce phage T5 exonuclease degradation, but has no effect on RecBCD digestion. When two genes for dZ biosynthesis and one gene for dATP hydrolysis from Salmonella phage PMBT28 (purZ (adenylosuccinate synthetase), datZ (dATP triphosphohydrolase), and mazZ ((d)GTP-specific diphosphohydrolase) were cloned into an E. coli plasmid, the level of dZ incorporation reached 19–20% of adenosine positions. dZ levels further increased to 29–44% with co-expression of a DNA polymerase gene from the same phage. High levels of dZ incorporation in recombinant plasmid are possible by co-expression of purZ, mazZ, datZ and phage DNA helicase, dpoZ (DNA polymerase) and ssb (single-stranded DNA binding protein SSB). This work expands our understanding of the dZ modification of DNA and opens new avenues for engineering restriction systems and therapeutic applications. Full article

Rigid polyurethane (PUR) foams are widely used across multiple industries due to their excellent thermal insulation and mechanical properties. However, their environmental impact, flammability, and limited thermal stability pose challenges for sustainable development. In this study, selected natural minerals—including talc, montmorillonite, halloysite, and diatomite—were incorporated into water-blown polyurethane foams to improve their performance while enhancing sustainability. The prepared foams were characterized in terms of apparent density, water uptake, compressive strength, dimensional stability, and thermal and fire resistance. The results indicate that the inclusion of mineral additives significantly improves the physical and mechanical properties of polyurethane foams, increasing durability, resistance to high temperatures, and fire safety. By using naturally occurring minerals, the study promotes the development of polyurethane foams with reduced environmental footprint, longer service life, and safer application potential in construction, automotive, and heating systems. These findings highlight the contribution of mineral-reinforced polyurethane foams to sustainable materials engineering and resource-efficient industrial applications. Full article

In the event of a fault in a shipboard medium-voltage direct-current (MVDC) power system, a fault reconfiguration method issues control commands to the switchgear to execute switching actions, thereby redistributing power flow, isolating the faulted zone, and restoring power to the de-energized loads. Existing fault reconfiguration strategies mainly use classical optimization methods. These methods are usually centralized, and as the system scale increases, they suffer from the curse of dimensionality, which degrades real-time performance and reduces computational efficiency. This paper proposes a MADRL-based fault reconfiguration method for shipboard MVDC power systems. The proposed method considers load priority levels, maximizes total restored load, and improves load balancing. To this end, a QMIX-based method, Dependency-Corrected QMIX with Action Masking (Dep-QMIX-Mask), was developed, introducing a dependency correction mechanism to handle action dependencies during decentralized execution and applying action masking to rule out invalid switching actions under operational constraints. A shipboard MVDC power system model was established and used for validation. Across three representative fault cases, Dep-QMIX-Mask achieves served load rates of 0.88, 0.67, and 0.43, with SLR improvements of up to 19.6% over baseline methods. It consistently produces feasible switching sequences in all 20 independent runs per case, improving feasibility by 10 to 30 percentage points. In addition, Dep-QMIX-Mask improves zonal load balancing by reducing the PUR variance by 40.5% to 99.2% compared with baseline methods. These results indicate that Dep-QMIX-Mask can generate feasible sequential reconfiguration strategies while improving both load restoration and load balancing. Full article

Rigid polyurethane (PUR) and polyisocyanurate (PIR) foams are widely used as thermal insulation materials due to their excellent thermal conductivity and low density. However, fire resistance remains a critical property determining their safe application in construction, transportation, and energy systems. This study provides a comparative overview of the fire behavior of PUR and PIR foams, focusing on structural aspects, decomposition mechanisms, flame retardancy, and performance of emission of toxic gases during the combustion process. Despite extensive studies on PUR and PIR foams, systematic comparative investigations addressing the combined influence of recycled PET-based polyester polyols, isocyanurate content, and fire-related properties—including thermal degradation, heat release, and toxic gas emissions—remain limited. PIR foams, characterized by higher isocyanate indices and the presence of isocyanurate rings, show superior thermal stability, reduced heat release rates, and enhanced char formation compared with PUR foams. Experimental analysis of thermal degradation (TGA/DTG) and heat release (cone calorimetry) confirms that PIR foams demonstrate higher resistance to ignition and slower fire propagation. The results emphasize the critical role of molecular architecture and crosslink density in shaping the fire performance of rigid foams, highlighting PIR systems as advanced insulation solutions for applications requiring stringent fire safety standards. The PIR foam was prepared using a polyester polyol derived from recycled PET, which could help in achieving better fire properties during the combustion process. Compared with PUR foams, PIR foams exhibited an approximately 50% reduction in peak heat release rate, an increase in char yield from about 3 wt.% to over 22 wt.%, and a shift of the main thermal degradation peak by approximately 55 °C toward higher temperatures, indicating substantially enhanced fire resistance. Full article

Background: Interpretation of radiographs is prone to diagnostic errors. Artificial intelligence (AI) has shown promising results in fracture detection, although systematic evaluation of software updates remains limited. This study compares the diagnostic performance of two versions of an AI-based fracture detection software in hand and ankle radiographs and assesses the influence of AI output on diagnostic decisions. Methods: This retrospective diagnostic accuracy study included 193 hand and ankle examinations obtained during routine clinical practice at Lillebaelt Hospital, Denmark. Radiographs were analysed using two versions of the same AI software and compared with the diagnostic report as the reference standard. Diagnostic performance of both versions was assessed using diagnostic accuracy metrics. Exploratory subgroup analyses were conducted to further investigate the difference in performance. The influence of AI was evaluated by the proportion of reports revised after review of AI output. Results: The newest software version demonstrated higher diagnostic performance than the older one (accuracy 0.933 vs. 0.824; p < 0.001). Similar improvements were observed across patient subgroups. Excluding radiographs containing casts resulted in only minimal changes in performance (accuracy in version 2: 0.930 vs. 0.933). In 8 of 15 discordant cases, reporting radiographers revised the initial assessment upon reassessment. Conclusions: The newest version demonstrated higher overall diagnostic performance, indicating that software updates can enhance the accuracy of AI-assisted fracture detection. The proportion of revised assessments suggests that radiographers’ decisions may be influenced by AI output. Full article

Carbon dioxide-derived oligocarbonate diols (OCDs) represent a promising class of sustainable raw materials that can enhance the environmental profile of polyurethane (PUR) coatings without compromising their performance. In this work, six oligocarbonate diols, differing in chemical structure (aromatic, aliphatic, and cycloaliphatic), were employed as modifiers in solvent-based PUR coatings designed for wood substrates. The study evaluates the influence of OCD’s chemical nature on the mechanical and optical properties of the resulting coatings. The results demonstrate that the structure of the oligocarbonate diol plays a decisive role in determining coating performance. PUR systems containing aliphatic soft segments exhibited the most favorable mechanical response, particularly in terms of wear resistance, outperforming coatings modified with cycloaliphatic and aromatic OCDs—wear reduction ranged between 43% and 71%. In contrast, the highest hardness values (0.46 and 0.41) were observed for the coatings incorporating aromatic moieties, indicating increased rigidity associated with aromatic structures. Importantly, adhesion at the wood–coating interface remained excellent and unaffected by the type of OCD used (cross-cut class I or II), confirming the compatibility of all investigated formulations with wooden substrates. Overall, the findings clearly show that newly developed CO₂-based oligocarbonate diols are effective and versatile modifiers for polyurethane wood coatings, enabling the tuning of functional properties while supporting more sustainable coating technologies. Full article

The efficacy of platelet-rich plasma (PRP) has long been associated with platelet concentration, yet clinical outcomes remain highly variable and frequently inconsistent. This review challenges the assumption that platelet count alone defines PRP efficacy, proposing instead that functional platelet quality and growth-factor bioactivity are equally critical determinants of therapeutic outcomes. Platelets act as carriers of bioactive molecules stored within alpha granules, including growth factors such as platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β), vascular endothelial growth factor (VEGF), and insulin-like growth factor (IGF), which orchestrate the cellular and molecular events of tissue repair. Variations in donor biology, age, metabolic status, and oxidative stress profoundly influence platelet functionality and growth-factor release. Likewise, centrifugation parameters, temperature control, and activation methods dictate whether these mediators are preserved or prematurely exhausted. Collectively, these findings reveal that platelet number alone cannot predict regenerative potency. The future of PRP standardization requires the integration of platelet quality indices, growth-factor quantification, and patient optimization protocols into clinical practice. By shifting focus from platelet enumeration to bioactivity assessment, regenerative medicine can achieve more consistent, personalized, and scientifically accurate outcomes. Full article

In the article we investigated the effectiveness of a synergistic system designed to reduce the fire hazard of flexible polyurethane (PUR) foams. The examined system consisted of a carbon-based filler graphene (G), carbon nanotubes (CNTs), or expanded graphite (EG) combined with melamine polyphosphate (MPP). The investigated polyurethane foams (PUR) were synthesized at room temperature via a polycondensation reaction between a polyol and an isocyanate, with an OH: NCO molar ratio of 2:1. Both the carbon fillers and melamine polyphosphate were homogeneously dispersed within the polyol component. Thermogravimetric analysis (TGA), cone calorimetry, and microcalorimetry were used to evaluate the influence of the fillers on the thermal stability and flammability of the PUR foams. The toxicity of the gaseous products was assessed using a coupled TG-gas analysis system, while the optical density of the evolved gases was determined using a Smoke Density Chamber (SDC). The obtained results demonstrated that the applied synergistic carbon-phosphorus filler system significantly reduced the fire hazard of the tested PUR foams. In particular, the EG5-MPP system enabled the formation of self-extinguishing materials. Full article

Background/Objectives: Active surveillance (AS) has become the standard of care for many men with localised prostate cancer, aiming to avoid the overtreatment of indolent disease while maintaining oncological safety. Despite improvements in diagnostic techniques, misclassification at diagnosis and the limited ability to predict disease progression remain major challenges in AS. Novel molecular and genetic biomarkers, assessed through liquid biopsy approaches, offer the potential to refine patient selection and support risk-adapted monitoring in AS. Methods: We conducted a narrative review of biomarkers in the context of AS for prostate cancer, framing the discussion in terms of the challenges in AS and how biomarkers may address these. PubMed and Embase were searched for English-language peer-reviewed studies published between 2000 and 2025. International guidelines (AUA, EAU, NCCN, NICE) and reference lists were reviewed manually. Priority was given to large prospective cohorts, meta-analyses, and high-impact publications. Results: Blood-based assays such as PHI and the 4K score, urinary tests including ExoDx and SelectMDx, and the Prostate Urine Risk (PUR) signatures have all shown associations with disease progression or decisions to undergo earlier treatment. However, studies are often small, use surrogate endpoints, and lack validation in MRI-integrated cohorts. Biomarkers appear most informative in men with Gleason Grade 1 (GG1) disease, while evidence in GG2 cohorts is limited. Cost-effectiveness, heterogeneity of endpoints, and uncertainty in managing discordant biomarker and MRI results remain barriers to clinical adoption. Conclusions: Molecular and genetic biomarkers show promise for improving AS by reducing diagnostic misclassification and enhancing prediction of progression. Future research should define clinically relevant cut-offs, clarify integration with MRI, and evaluate longitudinal use. Demonstrating utility in contemporary cohorts could enable the development of biomarker-guided, personalised AS that maintains safety while minimising harm. Full article