Search Results (548)

Self-assembled monolayers (SAMs) on indium tin oxide (ITO) surfaces tend to undergo molecular aggregation, resulting in non-uniform interfacial coverage and thus limiting the charge extraction efficiency and device performance in organic solar cells (OSCs). To address this issue, a novel dispersant molecule, 3,6-Diiodo-9-[2-(2-methoxyethoxy) ethyl]-9H-carbazole (2ICzMPE), featuring dipolar characteristics and flexible side chains, is designed and synthesized to regulate the interfacial distribution of 2PACz molecules on ITO electrodes. With a large dipole moment and steric hindrance, 2ICzMPE suppresses 2PACz aggregation, while the oxygen atoms in the side chains interact with the ITO surface, enabling a more uniform interfacial structure. Upon introducing 2ICzMPE, the interfacial energy level alignment is optimized, leading to more efficient charge extraction. Device physics analysis reveals suppressed carrier recombination and enhanced charge transport. As a result, the power conversion efficiency (PCE) of OSCs based on the PM6:L8-BO system is improved from 17.51% to 18.67%. This work provides a simple and effective molecular design strategy for constructing high-quality SAM interfaces and promoting the scalable application of OSCs. Full article

Bioactive peptides (BPs) are widely distributed and exhibit remarkable physiological activities. However, their natural forms are frequently characterized by short half-lives, low membrane permeability, poor stability, and inadequate oral bioavailability, which severely limit their applications in the food, pharmaceutical, and biomaterial fields. Therefore, modification and engineering of natural BPs are essential to surmount these inherent limitations. Synthetic biology-based modification strategies, including amino acid substitution, sequence truncation and hybridization, side-chain functionalization, and main-chain/side-chain integration, are comprehensively summarized in this review. Chemical modification strategies, such as terminal modification, cyclization, backbone modification, polymer conjugation, lipidation, and glycosylation, are also discussed, with particular attention to their advantages, potential drawbacks, and practical limitations. Based on 122 studies identified through systematic literature searches across major scientific databases, this review also discusses the current challenges and future trends in BP modification, providing theoretical guidance and innovative insights for the further development and enhanced utilization of BPs. Full article

Peptide therapeutics offer high target selectivity and low toxicity, but their clinical utility remains constrained by rapid proteolysis in vivo and negligible oral bioavailability. Incorporating non-canonical amino acids (ncAAs) provides a robust molecular engineering framework to overcome these pharmacokinetic bottlenecks. This review analyzes the structural and biophysical design rules of ncAA-mediated peptide stabilization, categorizing them into side-chain steric shielding, backbone conformational constraint, and stereochemical evasion of L-specific proteases. We systematically evaluate the biosynthetic milestones enabling this field, focusing on engineered orthogonal translation systems (tRNA/synthetase pairs, orthogonal ribosomes, quadruplet codons) and metabolic engineering strategies that supply fluorinated and other ncAA precursors de novo. Furthermore, we examine the translation of these technologies into clinical candidates (e.g., modified antimicrobial peptides, antibody–drug conjugates, and PROTACs) and identify scaling, immunogenicity, and computational modeling as key bottlenecks. This review serves as a technical reference for designing next-generation, hyper-stable peptide therapeutics. Full article

Natural lacquer, a bio-based polymer derived from Toxicodendron vernicifluum, has attracted renewed scientific interest as a sustainable coating material with exceptional mechanical durability, chemical resistance, and aesthetic qualities. This review synthesizes current knowledge on the chemical composition, enzymatic curing mechanisms, and structure–property relationships of lacquer-based polymer systems, with particular focus on recent advances in functional modification and processing technology. Key findings indicate that laccase-catalyzed oxidative polymerization, operating optimally at pH 6.0–7.5 and 20–30 °C, governs the formation of a highly cross-linked urushiol network whose properties are fundamentally determined by side-chain unsaturation and emulsion stability. Mechanistic analysis reveals that polyurethane hybridization improves weathering resistance by introducing flexible aliphatic segments and additional hydrogen-bonding cross-links, while graphene oxide incorporation enhances anticorrosion performance through a physical barrier mechanism that prolongs ionic diffusion pathways. UV-curable LPEA derivatives achieve an 83% reduction in curing time relative to ambient-cured lacquer, enabling integration with industrial spray-coating lines. Despite these advances, several critical limitations remain inadequately resolved. Allergen reduction strategies have not yet achieved sufficient quantitative efficiency for large-scale commercial deployment, and the long-term stability of nanocomposite lacquer films under sustained UV exposure and hydrothermal conditions is not well established. Furthermore, most high-performance modification systems reported in the literature are demonstrated only on laboratory scale, with scalability, substrate compatibility, and lifecycle performance remaining largely unvalidated. The review identifies the absence of standardized performance evaluation protocols and the fragmentation of structure–property data across studies as key barriers to systematic progress, and proposes that future work prioritize the development of integrated processing–modification–performance frameworks to guide the rational design of next-generation lacquer-based functional materials. Full article

Silicone rubber is an important external insulating material for composite bushings, composite insulators, and other power equipment. During long-term service, it is inevitably exposed to coupled environmental and electrical stresses, such as elevated temperature, moisture ingress, strong electric fields, and partial discharge, which may lead to hydrophobicity loss, surface chalking, crack propagation, and particle shedding. To reveal the microscopic degradation mechanism of silicone rubber under complex operating conditions, a molecular model of methyl vinyl silicone rubber was constructed using Materials Studio. A stable silicone rubber molecular structure was obtained through crosslinking, geometry optimization, and ensemble relaxation. Subsequently, a reactive molecular dynamics simulation system under coupled temperature–humidity–electric field conditions was established using LAMMPS and the ReaxFF reactive force field. Different temperature gradients, electric field intensities, and aging–recovery stages were designed to investigate the degradation behavior of silicone rubber. The evolution of the maximum carbon content, maximum silicon content, carbon-containing decomposition products, and typical small-molecule products, including H₂, H₂O, CH₄, C₂H₂, C₂H₄, and C₂H₆, was statistically analyzed. In addition, atomic trajectory tracking was performed to clarify the processes of methyl group detachment, Si-O bond cleavage, water molecule participation, and molecular chain reconstruction. The results show that high temperature mainly promotes methyl group detachment from side chains and fracture of the siloxane main chain, while a strong electric field accelerates the decomposition process and induces the transformation of long siloxane chains into shorter chains. Water molecules can react with broken siloxane chains to form hydroxyl-containing structures, making the structural degradation partially irreversible. The degradation process of silicone rubber under coupled temperature–humidity–electric field stress can be summarized as side-chain detachment, main-chain scission, water-assisted reactions, free-radical recombination, and local molecular aggregation. This study provides a molecular-level theoretical basis for aging mechanism analysis, condition assessment, and lifetime prediction of composite external insulating materials. Full article

The transition toward a circular economy is accelerating the development of high-performance, sustainable polymeric materials derived from renewable resources. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) represent a versatile class of biodegradable polyesters with inherent flexibility and tunable side-chain chemistry, making them attractive candidates for advanced polymer applications. Here, we report a novel class of bio-based polyurethanes (PUs) incorporating mcl-PHAs as soft segments, marking their first application in polyurethane synthesis and shifting towards greener PU synthesis. Polyurethane networks were prepared using castor oil (CO) and mcl-PHAs as polyols, with hexamethylene diisocyanate (HMDI) as a hard segment. Material properties were systematically tuned by varying the mcl-PHA/CO ratio (100/0 to 0/100), enabling precise control over structure–property relationships. Comprehensive characterization confirmed urethane bond formation and revealed predominantly amorphous materials with tunable thermal and mechanical behavior. Increasing mcl-PHA content enhanced elasticity and influenced phase organization, underscoring its role as a flexible, bio-derived soft segment. The resulting materials exhibited competitive mechanical performance alongside adjustable swelling behavior and morphology. Importantly, in vitro biocompatibility (MRC-5 fibroblasts) and eco-toxicological evaluation (Caenorhabditis elegans) confirmed the absence of toxicity. These findings highlight the potential of mcl-PHAs as sustainable building blocks for advanced polyurethane systems. Full article

Background/Objectives: Tuberculosis remains a major public health challenge due to the persistence of Mycobacterium tuberculosis (Mtb) and the emergence of multidrug-resistant strains. In this study, Pep-H, an HNP-1-derived antimicrobial peptide with the sequence RRYGTCIYQGRLWAF-NH₂, was used as a compact scaffold to examine how single-residue substitutions at the Cys position affected its biological and functional profile. Methods: A focused single-position substitution panel was generated by replacing Cys with Trp, Ala, Arg, or Met while preserving peptide length and sequence context, and the analogs were computationally prioritized according to their predicted antitubercular potential and contrasting side-chain properties. The peptides were synthesized, purified, characterized by HPLC and mass spectrometry, and evaluated for activity against Mtb H37Rv, cytotoxicity, hemolysis, ethidium bromide accumulation, and DPPH radical scavenging. Results: Pep-H retained the most favorable profile, showing the highest antimycobacterial potency, low hemolysis, favorable selectivity indices, enhanced ethidium bromide accumulation, and the strongest antioxidant response. All Cys substitutions reduced antimycobacterial activity, indicating that none of the tested residues reproduced the integrated biological profile of Pep-H. Conclusions: The contrasting outcomes of the Arg- and Met-containing analogs suggest that increased cationicity or sulfur retention alone was insufficient, while supporting a multifactorial contribution of Cys side-chain chemistry and the local GTCIY environment. Full article

The integrity of halal supply chains is increasingly threatened by fragmented paper-based records, certificate fraud, and the absence of real-time traceability. This paper presents HalalChain, a blockchain-based halal product traceability system that enforces role-based access control (RBAC) through three Solidity smart contracts deployed on an Ethereum-compatible blockchain. HalalChain is designed for production deployment on an EVM-compatible Layer-2 or sidechain such as Polygon or BNB Chain, on which the contracts run without code changes. A dual-storage architecture synchronises every supply chain event to both a PostgreSQL relational database and the blockchain, balancing on-chain immutability with off-chain query performance. The system supports five stakeholder roles, namely administrator, supplier, manufacturer, logistics, and retailer, each restricted to specific supply chain event types enforced at the smart contract level. Consumers can verify product halal status and full supply chain history by scanning a QR code linked to a public verification endpoint that cross-checks database records against on-chain event counts, producing a chain-integrity indicator. As the current chain-integrity check is count-base, it can detect missing or extra database rows, but it cannot detect content-level modification if the row count remains unchanged. A total of 107 automated test cases were executed covering functional correctness, edge cases, end-to-end integration, and gas performance benchmarks. Core smart contract operations consume between 25,365 and 213,684 gas units, indicating feasible deployability on Ethereum-compatible networks. An exploratory analysis was carried out with a preliminary survey of 40 respondents (mean = 4.10 on a 5-point Likert scale), suggesting that consumer demand for blockchain-verified halal certification is encouraging. The results demonstrate that HalalChain provides a tamper-evident, role-enforced traceability foundation for the halal food industry. The system secures the digital chain of custody cryptographically and the physical–digital binding between the QR code, and the product remains a separate trust assumption requiring complementary anti-tamper mechanisms. Full article

The Gram-negative bacterium Pseudomonas aeruginosa produces a family of peptide siderophores called pyoverdines that play a vital role in the mechanisms by which it acquires iron from the environment. A key component of various pyoverdines is the presence of one or more copies of L-δ-N-formyl-δ-N-hydroxyornithine (fOHOrn) as an iron-binding residue. In this study, we have developed an improved preparation of a derivative of fOHOrn that is suitable for use in solid-phase peptide synthesis, incorporating a novel N-oxidation protocol and a mild final deprotection with HCl/hexafluoroisopropanol (HFIP) that circumvents the unexpected deformylation of the fOHOrn side chain under acidic conditions. We have also devised a synthesis of the cyclic peptide component of pyoverdine D exploiting a selective side-chain deprotection strategy with HCl/HFIP that allows the application of readily available amino acids with standard tert-butyl side-chain protection and which facilitates the cyclisation step. These innovations open the way towards the convergent preparation of various pyoverdines and also other natural products that contain fOHOrn residues. Full article

Background/Objectives: Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) is an autosomal recessive disorder of mitochondrial fatty acid β-oxidation caused by pathogenic variants in ACADVL. The clinical spectrum is highly heterogeneous, ranging from lethal neonatal cardiomyopathy to late-onset myopathy. This study aims to characterize the rare c.215C>T (p.Ser72Phe) variant, identified in compound heterozygosity with the common pathogenic allele c.848T>C (p.Val283Ala) in a male neonate detected by newborn screening (NBS). Methods: Genetic analysis was performed using Sanger sequencing on the proband and his family members. The pathogenicity of the p.Ser72Phe variant was evaluated through multiple bioinformatic predictors and interpreted according to ACMG/AMP guidelines. To understand the functional impact on the protein, structural modeling was conducted using FoldX 4.0 for energy calculations and UCSF ChimeraX for the visualization of conformational changes and cofactor-binding site perturbations in the VLCAD homodimer. Results: At the end of the first postnatal week, liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis of dried blood spots of the proband revealed a markedly abnormal acylcarnitine profile, with C14:1 levels (1.837 μmol/L) approximately five times above the reference range. Clinical reports documented hypoketotic hypoglycemia, consistent with VLCADD. Segregation analysis demonstrated transmission of both variants within the family, with additional heterozygous and homozygous carriers identified. Bioinformatic predictions uniformly classified p.Ser72Phe as deleterious. This variant has an extremely low allele frequency and affects a highly conserved residue in the FAD-binding domain. Structural modeling with FoldX yielded a mean ΔΔG of +22.63 ± 5.48 kcal/mol, indicating a significant localized thermodynamic burden. Inspection of the mutant model in ChimeraX showed perturbation of the side-chain orientation and attenuation of the local hydrogen-bonding network at the FAD-binding site, together with increased steric packing around residue 72. Taken together, the clinical, genetic, and structural evidence support reclassification of p. Ser72Phe as likely pathogenic according to ACMG criteria, specifically applying the ClinGen ACADVL VCEP specifications. Conclusions: This study expands the ACADVL mutational spectrum and underscores the value of integrating sequencing, segregation, and structural bioinformatics in interpreting rare variants detected through NBS. Full article

Background: Recent work has revealed that protein-coding sequences encode regulatory information influencing mRNA stability and translation through a nascent peptide code. However, the evolutionary origin of this regulatory layer remains unclear. This study aims to determine when peptide-mediated translational control emerged during the evolution of the proteome and genetic code. Methods: Dipeptide-specific effects on mRNA stability and translation were integrated with a phylogenetic timeline of dipeptide emergence derived from dipeptide sequences across proteomes. Each of the 400 canonical dipeptides was assigned an evolutionary age, and experimentally derived regulatory effects were mapped onto this timeline, with associations assessed using rank-based correlation and regression analyses. Results: A weak but statistically significant negative association was observed between dipeptide age and mRNA stability, indicating that more recently evolved dipeptides tend to destabilize transcripts. This trend was stronger at the amino acid level, where later-emerging residues showed greater contributions to reduced mRNA levels. Destabilizing effects were associated with physicochemical properties such as positive charge, side-chain bulkiness, and β-strand propensity. Mapping these effects onto codon space revealed a non-random distribution aligned with the evolutionary and structural organization of the genetic code. Destabilizing effects were also enriched within specific codon exchange groups, indicating that regulatory signals are structured within the degeneracy and mutational neighborhoods of the code. Conclusions: These findings indicate that the nascent peptide code is a late evolutionary innovation linked to amino acid expansion and proteomic complexity, with regulation embedded within both peptide sequences and the degeneracy structure of the standard genetic code. Full article

Background and Objectives: Sjögren’s disease (SjD) is a chronic autoimmune disorder in which the immune system attacks the glands that produce tears and saliva, leading to symptoms such as dry eyes and dry mouth. If left untreated, SjD can also cause inflammation and damage to other parts of the body, including the skin, lungs, kidneys, and nervous system, and increase the risk of developing lymphoma. The human leukocyte antigen (HLA) class II molecule HLA-DR3 is strongly associated with SjD. Materials and Methods: To investigate how post-translational modifications (PTMs) influence the presentation of SjD-associated autoantigens by HLA-DR3, we employed a computational framework to determine the binding of PTM-mimic peptides to HLA-DR3. We further supported the in-silico results with in-vitro experiments. Results: Our analysis revealed that PTM-mimic substitutions at canonical anchor positions rarely improved predicted binding affinity using the Stabilized Matrix Method, with most modifications resulting in reduced affinity. However, a comprehensive analysis of full-length SjD-associated autoantigen sequences (Ro60, Ro52, La) identified discrete regions with high densities of PTM-eligible anchor sites, specifically, the Ro60 HEAT solenoid, Ro52 RING/B-box/PRY-SPRY modules, and the La motif-RRM1 region, suggesting that PTMs may alter epitope presentation in a sequence-dependent manner. Experimental validation of selected PTM-mimic peptides showed enhanced T cell responses, which were associated with increased binding affinity to HLA-DR3. Structural modeling of a representative complex revealed that PTM-mimic peptides adopt a slightly shifted backbone orientation and altered side-chain positioning, leading to a larger peptide–DR3 interaction interface. Conclusions: These findings provide new insights into the role of PTMs in shaping the immunogenicity of SjD-associated autoantigens and highlight the potential for PTM-mimic peptides to modulate T cell responses in SjD. Full article

Traditional activated clay (AC) bleaching usually shows limited adsorption selectivity, leading to micronutrient loss during pigment removal, and also suffers from high residual oil retention and poor regenerability. Developing mild bleaching materials with both high adsorption efficiency and selectivity is therefore important for oil refining. Mesoporous Al-MCM-41 (AM) adsorbents with different Si/Al ratios were prepared and characterized in pore structure and acidity, and the bleaching performance against AC in terms of pigment removal and the retention of micronutrients in rapeseed oil and the bleaching mechanism were studied. The results showed that AM25 (Si/Al = 25) exhibited the best overall performance among the AM samples under the tested conditions (70 °C, 20 min). It achieved a bleaching efficiency of 92.3% and removed 94.56% of chlorophyll, 92.94% of lutein, and 84.09% of β-carotene. In addition, AM25 reduced the peroxide value from 2.52 to 0.58 mmol/kg. High retentions of tocopherols (93.89%), phytosterols (98.73%), and squalene (96.32%) were also observed. Meanwhile, the adsorption rates of α-tocopherol, brassicasterol, and α-linolenic acid showed the highest values in their relative homologues of tocopherols, phytosterols, and free fatty acids (FFAs), respectively, due to differences in the methyl amount of tocopherols, the side-chain unsaturation of phytosterols, and the fatty acid chain unsaturation of fatty acids. Furthermore, the kinetic and isotherm data for chlorophyll and carotenoids were better described by the pseudo-second-order and Freundlich models, respectively. Combined with thermodynamic analysis, they indicated that adsorption was a spontaneous, endothermic, entropy-driven, heterogeneous multilayer process dominated by physical adsorption. Further, pigment adsorption was mainly governed by uniform mesopores and Si–OH/Si–OH–Al sites in AM. Among them, carotenoid removal depended primarily on the dispersion effect of moderately strong acid sites within pore-confined regions, whereas chlorophyll removal was more sensitive to the number of acidic sites in AM. AM25 still maintained 83.31% bleaching efficiency after five regeneration cycles. These performances of AM25 are significantly superior to that of AC. Full article

Alsophila spinulosa is a tree fern designated as a second-class nationally protected species in China and valued for its medicinal and ornamental properties. Its slow growth and susceptibility to environmental stresses pose challenges to its cultivation. Plant-growth-promoting rhizobacteria (PGPR) can enhance plant development by producing phytohormones, such as indole-3-acetic acid (IAA). In this study, 39 IAA-producing strains were isolated from the rhizosphere of A. spinulosa. Morphological and molecular analyses identified the highest IAA-producing strain, R74, as Burkholderia pyrrocinia. Its optimal inoculum age was determined to be 12–20 h, and its optimal culture conditions for IAA production were 24 h of incubation, 32 °C and pH 7.0. Whole-genome sequencing revealed that the genome of strain R74 is 8,347,169 bp in size with a GC content of 67%, comprising 7543 genetic elements. Further genomic analysis showed that IAA biosynthesis in R74 involves the tryptophan side-chain oxidase (TSO) pathway and the tryptophan-independent pathway. Pot experiments revealed that inoculation with R74 increased the height, root length, stem diameter, and biomass of A. spinulosa seedlings. It also increased antioxidant enzyme activities, elevated soluble protein and chlorophyll contents, and reduced malondialdehyde levels. This study provides an empirical basis for the development of Burkholderia-based biofertilizers to promote A. spinulosa growth. Full article

Raman spectroscopy (RS) provides detailed information on molecular structure but remains challenging for low-scattering proteins in complex media. Myelin basic protein (MBP) is a key structural component of central nervous system myelin and a clinically relevant molecule in demyelinating disorders; however, to the best of our knowledge, its Raman signature in solution has not been reported. In this work, Raman and surface-enhanced Raman spectroscopy (SERS) were employed to characterize purified human myelin basic protein (MBP) in aqueous solution and cerebrospinal fluid (CSF). Quasi-spherical silver nanoparticles were used as SERS elements, yielding enhancement factors of 10⁵ and increasing sensitivity to MBP-associated spectral changes at low concentrations. The MBP spectrum exhibited vibrational modes primarily associated with amide II and amide III bands, as well as aromatic side-chain contributions. Comparative analysis of MBP, CSF, and MBP-spiked CSF samples revealed significant spectral overlap, limiting discrimination based solely on peak positions. To overcome this limitation, spectral correlation and band-intensity-ratio analyses were applied, revealing reproducible trends associated with increasing MBP content. While individual MBP bands are not exclusive, the observed spectral patterns demonstrate the sensitivity of RS and SERS to MBP-induced spectral changes in CSF. These findings should be interpreted as a proof-of-concept in a single-donor CSF matrix. Full article