Search Results (2,951)

Yttria-stabilized zirconia (YSZ) thermal barrier coatings suffer from t′ phase destabilization and insufficient thermal insulation above 1200 ℃. In this work, YbO_1.5-stabilized ZrO₂ powders (xYbSZ, x = 4–12 mol% YbO_1.5 on a cation basis, equivalent to 2–6 mol% Yb₂O₃) were synthesized by chemical co-precipitation, consolidated by spark plasma sintering, and evaluated at 1300 ℃ in terms of phase stability, sintering behavior, thermal conductivity, and fracture toughness. A common compositional boundary near 8 mol% YbO_1.5 was identified across all four responses. 8YbSZ retained the metastable t′ phase with a monoclinic content below 10 mol% after 300 h at 1300 ℃, whereas grain coarsening accelerated markedly and the thermal conductivity reduction efficiency per unit doping at 1000 ℃ was approximately halved beyond this composition, with κ decreasing from 2.41 to 1.96 W·m⁻¹·K⁻¹ across the series. The toughness gain produced by thermal treatment fell from 34% (4YbSZ) to about 10% (10–12YbSZ) as the dominant toughening mechanism shifted from transformation and microcrack toughening (4–6 mol%) to ferroelastic domain switching (8 mol%), with both being lost in the compositions in which the cubic phase predominated. These results identify 8 mol% YbO_1.5 as the optimal composition balancing phase stability, sintering resistance, thermal insulation, and mechanical integrity for TBC applications at 1300 ℃. Full article

γ-Hydroxybutyric acid (GHB), a colorless and odorless central nervous system depressant associated with drug-facilitated sexual assault, demands rapid on-site detection. Polydiacetylene (PDA) colorimetric sensors derived from 10,12-pentacosadiynoic acid (PCDA) conjugates are a promising platform, but the molecular origin of GHB recognition in PCDA–gabazine systems has remained unresolved. Here, we compare a series of structurally related PCDA conjugates to examine how the chemical state of the EDA-derived unit affects the GHB-induced colorimetric response. A side-by-side substituent screen of three PCDA derivatives showed that PCDA–EDA produced the largest colorimetric response (ΔR = 53) within 30 s, the hydrazide analogue gave a moderate response (ΔR = 34), and a simple amide was negligible (ΔR = 12). By contrast, a PCDA–gabazine mat prepared by the same protocol showed only a subtle, barely discernible color shift after several hours and remained predominantly blue even after approximately 24 h, without a visually appreciable blue-to-red transition. This difference suggests that the accessible free primary amine of PCDA–EDA is an important factor contributing to its faster and stronger response. Building on this mechanistic finding, we replaced the previously used PVDF–HFP/PEO matrix with a cellulose/PVDF–HFP formulation processed from DMF and adopted multi-nozzle electrospinning, reducing the fabrication time from approximately 120 to 30 min per sheet, corresponding to a 75% reduction in processing time. The sensor mat showed a clearly distinguishable, dose-dependent visual response across 0.5–3% w/v GHB within 30 s, covering the forensically relevant concentration window. These findings reposition linker architecture as a central design parameter for PDA-based forensic colorimetric sensors. Full article

Environmental chemical exposures are increasingly recognized as contributors to metabolic dysfunction, particularly when they occur as chronic, low-dose mixtures rather than as isolated high-dose toxicants. However, current approaches often focus on exposure intensity, single-compound hazard or isolated biomarker associations, and provide limited explanation for why individuals with comparable exposure profiles may develop markedly different metabolic outcomes. This semi-systematic review proposes an Exposure–Adaptive Capacity (EAC) framework to interpret the metabolic consequences of environmental chemical mixtures through the interaction between exposure burden and host adaptive capacity. A structured literature search covered PubMed/MEDLINE, Scopus and Web of Science records published through 30 June 2026; a reviewer-triggered PubMed/MEDLINE update was executed on 30 July 2026 using harmonized British and American dyslipidaemia/dyslipidemia terms, explicit eligibility domains and evidence-mapping procedures. The review integrates epidemiological, mechanistic, toxicological and translational evidence related to environmental chemicals, metabolic dysfunction, mitochondrial impairment, oxidative stress, inflammation, endocrine disruption, metabolic resilience and biomarkers. The evidence indicates that several chemical classes, including per- and polyfluoroalkyl substances, bisphenols, phthalates, pesticides, persistent organic pollutants and selected metals, converge on mitochondrial bioenergetics, redox regulation, inflammatory signalling, endocrine and nuclear receptor activity, nutrient-sensing networks and adipose tissue function. The EAC framework defines exposure burden as the cumulative biological pressure imposed by chemical mixtures and adaptive capacity as the organism’s functional ability to buffer, compensate for or recover from exposure-induced metabolic stress. To make the framework empirically testable, we specify measurable domains for exposure burden, adaptive capacity and EAC mismatch, and distinguish biomarkers of exposure, early biological effect, adaptive capacity, metabolic dysfunction and vulnerability. A quotient-based expression is retained only as a heuristic representation, while empirical testing is proposed through exposure-by-adaptive-capacity interaction models and complementary multidimensional approaches. The framework provides a structured basis for future exposomic, epidemiological and translational studies by shifting attention from exposure alone to the balance between environmental pressure and biological resilience. Full article

Membrane separation has become a key technology for advanced water purification and control of emerging contaminants because of its high separation efficiency, low chemical demand, and ease of integration. However, organic membrane fouling induced by the coupling of dissolved organic matter and coexisting metal ions remains a major obstacle to stable and efficient membrane operation. This review focuses on metal ion-mediated formation of organic aggregates in the bulk solution and their governing role in membrane fouling behavior. The review summarizes how metal ions regulate organic aggregate formation through distinct dominant mechanisms. Na⁺ mainly screens electrostatic repulsion, Ca²⁺ promotes ion bridging and cross-linking, and Mg²⁺ often induces weaker bridging or hydration-mediated effects due to its stable hydration shell. The review further discusses the dual effects of mixed foulants and dynamic fouling layers on the rejection of emerging contaminants. In addition, current control strategies, including pre-coagulation, pre-oxidation, and catalytic functional membranes, are evaluated from the perspective of regulating aggregate structures and interrupting interfacial deposition. Finally, future research should shift from membrane-interface-centered analysis to bulk-phase aggregation, establish quantitative structure–effect relationships between aggregate properties and fouling behavior, and promote fouling-control strategies from mechanistic effectiveness toward engineering practicality. Full article

Hydrogen-bond organization plays a central role in determining the structure and properties of water from molecular to macroscopic scales. In this study, we propose a geometry-based descriptor for small hydrogen-bonded water clusters, (H₂O)_n, with n = 2–6. The central element of the proposed geometric framework is the dimensionless geometric index, S_n = d/l, where d is the center-to-molecule distance in a cluster configuration and l is the nearest-neighbor O···O distance associated with hydrogen-bonded water molecules. The geometric descriptor is not intended to replace quantum-chemical calculations or to provide a direct measurement of hydrogen-bond energy, lifetime, or number. Instead, it provides a compact geometric framework for describing the structural organization of small hydrogen-bonded water clusters. The obtained geometric trend is compared with selected Nuclear Magnetic Resonance (NMR), Møller–Plesset perturbation theory (MP2), and radial distribution function data as complementary qualitative and semi-quantitative references. The proposed geometric index S_n = ${\displaystyle \frac{d}{l}}$ was further compared with MP2 quantum-chemical O···O distances for (H₂O)_n clusters, n = 2–6, using the oxygen atoms as structural nodes of the hydrogen-bonded motifs. This comparison showed that the exponential increase in S_n is consistent with the characteristic O···O donor–acceptor length scale of approximately 2.8 Å, linking the geometric framework with calculated molecular geometries. Over the limited interval n = 2–6, the geometric index Sn increases monotonically and nonlinearly with cluster size. The quantum-chemical reference data previously reported in our study, comprising GIAO-DFT-calculated ¹H chemical shifts obtained for MP2-optimized water-cluster geometries, show a rapid nonlinear increase from the dimer to the pentamer, followed by the onset of saturation in the pentamer–hexamer range. The semi-empirical stabilization parameter evaluated in the present study indicates increasing relative stabilization, with a reduced incremental change around n ≈ 4–5. The qualitative consistency of these size-dependent trends supports the use of Sn as a compact geometric descriptor of hydrogen-bond organization in small water clusters, without interpreting it as a direct quantitative measure or mechanistic framework of hydrogen-bond cooperativity. Importantly, liquid water is not treated as a system of closed cyclic clusters; cyclic motifs are used only as frameworked geometric reference configurations for small hydrogen-bonded aggregates. The geometric trend is qualitatively compared with selected quantum-chemical, spectroscopic, and radial distribution function data and should be regarded as an empirical geometric approximation over the limited interval n = 2–6. These findings indicate that geometric, spectroscopic, and quantum-chemical descriptors reflect related, but not identical, aspects of hydrogen-bond organization. The proposed approach links cluster geometry, O···O intermolecular distances, and hydrogen-bond connectivity in a simplified geometric description. Full article

The urgent need for bio-based functional materials has driven a shift away from fossil-fuel-sourced materials toward renewable lignocellulosic biomass (LCB). This comprehensive review explores the advancements in LCB carbonization between 2020 and 2026, marking a shift from traditional, low-yield combustion processes toward highly selective and sustainable thermochemical conversion pathways. The primary objective of this review is to evaluate the integration of green pretreatment strategies, conversion technologies, and efficient valorization of the aqueous effluents and by-products. The goal of green pretreatment is to overcome the inherent recalcitrance of LCB without the use of harsh chemicals and reaction conditions, specifically highlighting the effectiveness of deep eutectic solvents (DESs) and ionic liquids (ILs). The review also evaluates the emerging conversion technologies, including hydrothermal carbonization (HTC), microwave-assisted pyrolysis (MAP), and the synergistic co-pyrolysis of LCB with synthetic polymeric wastes. Another novel concept in preparing hard carbon and other related materials is the “lignin-first” biorefinery strategy, which facilitates the subsequent production of high-value aromatic monomers, platform chemicals, and biofuels. The engineered carbon materials are increasingly utilized well beyond their traditional use as solid fuels. The products have been proven to be excellent for use in high-performance energy conversion and storage, serving as renewable bio-based electrode materials for supercapacitors and carbon electrodes in next-generation batteries. Full article

Geochemical proxies in coastal sediments are widely applied to reconstruct past climatic and environmental changes, yet their sensitivity to climate versus localized depositional processes remains debated in dynamic land–sea interfaces. Here, we present major, trace, and rare earth element (REE) data from two Holocene sediment cores (QX01 and QX02) from the western coast of Bohai Bay to decouple provenance, weathering, and hydrodynamic controls. Provenance-sensitive trace element ratios (La/Sc and Th/Sc) and REE fractionation patterns indicate exceptional source stability dominated by the Yellow River and adjacent cratonic catchments throughout the Holocene, eliminating provenance shifts as a confounding variable. Since ~8 ka, an overarching upward increase in raw chemical index of alteration (CIA), accompanied by increasing Al/Si ratios and grain sizes, broadly aligned with the warm and humid Holocene Climate Optimum. Crucially, a highly significant linear relationship between grain size, Al/Si and CIA (R² > 0.78) demonstrates that raw CIA variations were decisively modulated by sea-level-driven hydrodynamic sorting during the Holocene transgression, which shifted the depositional setting from high-energy fluvial regimes to low-energy marine settings, preferentially trapping fine-grained, clay-hosted aluminosilicates with inherently high CIA values. During the late Holocene (~5 ka to present), stabilizing sea-level conditions shifted the raw records into an elevated plateau punctuated by high-frequency fluctuations and localized geochemical anomalies, reflecting a dynamic interface sensitive to episodic fluvial floods or tidal/storm reworking that periodically introduced coarser, quartz-rich detritus. The resulting sorting-corrected CIA_C removes the transgressive clay-trapping artifact and reveals a broad, subdued weathering plateau between ~8 ka and 4 ka BP, consisting with previous Chinese Loess Plateau weathering intensity. These findings highlight that in dynamic marginal-marine sinks, raw silicate weathering indices reflect physical sorting overprints, and hydrodynamic detrending is essential to extract genuine continental paleoclimate signals. Full article

Fresh pork remains susceptible to psychrotrophic spoilage during superchilled storage. Although oregano essential oil (OEO), nisin, and active absorbent pads have each been studied, their effects on spoilage-community proliferation and concurrent quality loss remain poorly resolved. Here, we coupled longitudinal 16S rRNA gene profiling with conventional microbiological and quality measurements to evaluate a poly(vinyl alcohol)/soy protein isolate pad containing OEO-loaded soluble soybean polysaccharide-nisin nanoparticles (PS-NPs). Pork was stored at −1 °C for 24 days without a pad (CK), with a nanoparticle-free pad (PS), or with PS-NPs. Bacterial communities in CK and PS-NPs were profiled alongside total viable count, TVB-N, TBARS, protein carbonyls, color, water-holding capacity, and sensory quality. Compared with CK, PS-NPs slowed the increase in viable counts and delayed physicochemical and sensory deterioration. On day 24, Pseudomonas relative abundance was 39.48% with PS-NPs and 51.02% in CK. TBARS and protein carbonyl contents were 36.96% and 19.44% lower than CK, respectively, while cooking loss was 28.49% versus 32.18%. Among the evaluated taxon-quality pairs, Pseudomonas psychrophila showed the strongest positive association with protein carbonyl content. Unlike earlier performance-focused studies, this work links packaging-associated community shifts with concurrent chemical, physical, and sensory changes under superchilling. The findings support PS-NPs as a preservation strategy. Full article

Neurotoxicity is generally thought to result from exogenous agents like environmental chemicals, drugs and biological toxins. However, increasing evidence suggests that many endogenous molecules that play a critical role in normal brain function can become neurotoxic when the regulatory mechanism involved in their production, metabolism, compartmentalization and clearance are disrupted. This shift underlies the basis of endogenous neurotoxicity. This review discusses the major endogenous sources of neurotoxicity: metabolic neurotoxins, dysfunctional neurotransmitters, protein aggregates and inflammatory mediators. These endogenous factors arise from different physiological pathways, but share common pathogenic mechanisms, all of which involve an underlying state of oxidative stress, mitochondrial dysfunction, impaired proteostasis, excitotoxic signalling, neurovascular dysfunction and maladaptive neuroglial responses. This is not a singular process but a network of interconnected processes, which work together to progressively diminish neuronal resilience and promote synaptic dysfunction and neurodegeneration. The review also underscores the critical role of astrocytes, microglia and other glial cells in the maintenance of neuronal homeostasis. By integrating diverse endogenous neurotoxic pathways within a unified homeostasis-centred framework, this review provides a broader perspective on the mechanisms linking metabolic disorders, aging and neurodegenerative diseases. This framework suggests that effective therapeutic strategies may require restoration of physiological regulatory networks rather than targeting individual neurotoxic molecules in isolation. A systems-level understanding of endogenous neurotoxicity may therefore facilitate the development of earlier biomarkers and more effective interventions aimed at preserving neuronal homeostasis and preventing progressive neurological dysfunction. Full article

Per- and polyfluoroalkyl substances (PFASs) are persistent synthetic chemicals of global concern. While most research has focused on their occurrence and toxicity, far less attention has been paid to their impacts on the global carbon cycle. This review synthesizes current evidence on how PFASs influence carbon cycling across soils, aquatic systems, and the atmosphere. In soils, PFASs alter organic carbon inputs by affecting plant biomass and root exudates and shift microbial community composition and enzyme activities, thereby modulating organic matter decomposition. In aquatic ecosystems, PFASs biologically impair carbon sequestration by inhibiting plankton, and abiotically interact with extracellular polymeric substances to prolong the cycling of dissolved organic carbon. The atmosphere acts as a key mediator as follows: thermal treatment of PFASs generates perfluorocarbons, potent greenhouse gases that exacerbate global warming and further disturb carbon cycling. Despite clear disruptive effects, major knowledge gaps remain. Future research should use quantitative structure–property relationship modeling to assess PFAS alternatives (e.g., PFHxS), and employ advanced molecular tracking (e.g., isotopic labeling, NanoSIMS) and machine learning to unravel nonlinear PFAS–carbon dynamics. Improved detection technologies are needed to identify greenhouse gas byproducts from PFAS thermal treatment. Ultimately, deploying high-resolution flux observation networks and integrating PFAS dynamics into Earth system models and carbon-accounting frameworks are critical for predicting carbon–climate feedback and supporting global carbon neutrality goals. Full article

Lethal foodborne illness outbreaks represent a critical intersection of public health surveillance, environmental health, and forensic toxicology. When acute gastrointestinal syndromes lead to sudden death, traditional postmortem investigation techniques are often hindered by tissue autolysis and the overgrowth of putrefactive microflora, which complicate conventional microbiological assays. This review establishes a comprehensive framework for chemical forensics by evaluating the utility of stable isotope analysis (SIA) as a supportive, probabilistic chemical proxy to complement traditional epidemiological investigations of postmortem food contamination sources. Following JBI scoping review guidelines and the PRISMA-ScR reporting framework, data from 42 peer-reviewed articles (2000–2026) were charted and synthesized to map natural isotopic variations (δ¹³C, δ¹⁵N, δ¹⁸O, δ²H and δ³⁴S) across both forensic decedents and environmental reservoirs. The findings outline a structured, multi-tissue diagnostic cascade governed by biological metabolic turnover rates: unabsorbed gastric chyme provides a direct chemical match to contaminated source food items within a hyper-acute 0–6 h window; high-turnover visceral matrices (liver, blood plasma) shift to reflect acute exposure profiles within 1–7 days; and continuously fixed keratinized matrices (hair, nails) archive multi-month dietary and transcontinental transit histories. Furthermore, compound-specific isotope analysis (CSIA) of individual amino acids offers unprecedented structural resolution, utilizing the carbon discrimination metric (Δ¹³C_glu-phe) to differentiate pristine agricultural signatures from endogenous metabolic distortions while biochemically verifying pre-mortem physiological stress and hyper-catabolic muscle wasting. Taphonomic thresholds were explicitly defined, establishing that bulk visceral soft tissues remain isotopically stable (±0.3‰) for up to 48 h at room temperature (~21 °C) before microbially induced nitrogen enrichment (δ¹⁵N > +2.8‰) alters native profiles, whereas hair and nail keratin maintain absolute isotopic stability for over 180 days postmortem. When pristine multi-isotope signatures are coupled with mandatory chloroform–methanol lipid extraction and processed through spatial Bayesian assignment models, geographic provenance tracking via environmental isoscapes achieves a predictive accuracy of 97%. This review introduces a standardized environmental health protocol designed to harmonize field environmental sampling with medical autopsies. This protocol provides a legally robust strategy for investigating unresolved lethal foodborne illness case-outbreaks, particularly those involving pediatric mortalities linked to the consumption of counterfeit or fraudulent food products in low- and middle-income countries. Furthermore, it aims to strengthen national and municipal legal frameworks and international biosecurity enforcement. Full article

Background/Objectives: Garlic (Allium sativum) has long been valued for its rich constellation of organosulfur and phenolic compounds, molecules that underpin its many recognized biological activities. Despite its deep roots in traditional medicine, the functional profile of garlic is far from uniform; it shifts notably depending on how its bioactive components are extracted. Most scientific attention has gravitated toward ethanolic extracts, leaving the behavior of aqueous-buffer preparations relatively unexplored. In this study, we evaluated the antioxidant, antimicrobial, and exploratory immunometabolic effects of extracts obtained with phosphate-buffered saline (PBS) and 50% ethanol in PBS (EtOH:PBS; 50:50, v/v), using a regional garlic variety (“Jaspeado”) cultivated in northwestern Mexico. Methods: Their antioxidant potential was profiled through DPPH, ABTS, and ORAC assays; phenolic content was quantified using the Folin–Ciocalteu method, and a broader chemical fingerprint was obtained through UPLC-ESI-TQ-MS/MS. Furthermore, we analyzed their antimicrobial action against Escherichia coli, Salmonella spp., and Staphylococcus aureus, and examined their immunometabolic influence in LPS-stimulated 3T3-L1 adipocytes. Results: The extracts showed distinct, solvent-dependent patterns of antioxidant activity. The PBS extract displayed the highest ORAC values, whereas the EtOH:PBS extract showed a stronger DPPH and ABTS activity and a higher phenolic recovery. The PBS extract exhibited a broader bacteriostatic effect, inhibiting the growth of all strains, and selectively modulated antioxidant gene expression and influenced cytokine changes in adipocytes. Conclusions: Overall, this regional garlic variety exhibits solvent-dependent antioxidant and antimicrobial activities, while the PBS extract provided a biocompatible preparation for exploring relationships between chemical composition and biological activities. Full article

In semi-humid loess regions, young apple–soybean alley-cropping is constrained by water competition and phenolic accumulation, but how emitter-line layout reorganizes soil biochemical environment remains unclear. This study evaluated whether locally used management systems differed in the spatial coupling of phenolic load, biological activity, and productivity. A two-year field experiment compared rainfed apple monoculture, rainfed soybean monoculture, rainfed apple–soybean alley-cropping, and drip-irrigated alley-cropping with one emitter line per soybean row (DL1), per two rows (DL2), or per three rows. Drip-irrigated monoculture was not included because monocultures are generally rainfed locally owing to lower water demand relative to regional precipitation. Soil phenolics, enzyme activities, microbial abundances, yield, and WUE were assessed using spatial profiling, PLS-SEM, SHAP-based model interpretation, and a network-informed soil quality index (SQI). Drip-irrigated alley-cropping, particularly DL1 and DL2, was associated with lower phenolic load and higher biological activity than rainfed systems. Under DL treatments, phenolics were concentrated mainly in the 40–60 cm layer, whereas enzymes and microorganisms remained enriched in the 0–20 cm layer and shifted horizontally away from the tree row, indicating reduced spatial overlap between chemical constraints and biological activity. Productivity was more closely associated with microbial abundance under rainfed conditions but with enzyme activity under drip irrigation. The network-informed SQI discriminated treatments more clearly than conventional indices. DL1 had the highest SQI, whereas DL2 achieved the highest productivity. Among locally relevant systems, DL2 provides a practicable emitter-line layout that balances soil biochemical improvement with crop productivity. Full article

Background: Over the past decades, the global onset of menarche has progressively advanced, driven by complex interactions between metabolic, psychosocial, and environmental factors. Beyond its reproductive significance, menarche represents a critical developmental milestone that coincides with increased vulnerability to mental health difficulties. Contemporary determinants such as childhood obesity, early-life adversity, and exposure to endocrine-disrupting chemicals (EDCs) may accelerate pubertal timing while simultaneously shaping adverse psychological trajectories during adolescence. Objectives: This review aims to provide a translational and clinically oriented synthesis of modern determinants of earlier menarche and their associations with mental health outcomes in girls and adolescents, highlighting implications for early identification, prevention, and integrated clinical care. Methods: We conducted a narrative review mapping a scoping literature search conducted using PubMed/Medline, Scopus, and PsycINFO, focusing on literature from the last decade (2016–2026), with emphasis on systematic reviews, meta-analyses, and longitudinal cohort studies. Evidence was synthesized across biological, psychosocial, and environmental domains. Results: Accumulating evidence indicates that higher childhood adiposity, psychosocial stress, and EDC exposure are consistently associated with advanced pubertal timing. Earlier menarche correlates with an elevated risk of depressive symptoms, anxiety, self-harm, and body image-related distress, although effect sizes vary across populations. Emerging longitudinal data suggest that the peri-menarcheal period represents a critical window for symptom exacerbation. These associations appear to be mediated by biological mechanisms (e.g., hormonal shifts, hypothalamic–pituitary–adrenal (HPA) axis reactivity) and social processes including peer-comparison dynamics and premature sexualization. Conclusions: Earlier menarche acts as a biopsychosocial sentinel event rather than an isolated gynecological milestone. Integrating mental health screening and anticipatory guidance into pediatric and gynecological care is essential for early risk detection. A multidisciplinary, equity-oriented approach is required to address both individual vulnerability and broader environmental determinants. Full article

Switchable β-barrel-type fluorescent proteins are essential genetically encoded probes for super-resolution imaging. The space required for chromophore cis–trans isomerisation can also provide an opportunity to introduce bulkier chemistry at the 3-position of the phenolic ring. Here, we report, to our knowledge, the first successful genetic encoding of 3-cyano-L-tyrosine (3CNY) into a protein. Using genetic code expansion, the cyano-containing tyrosine derivative is incorporated directly into the chromophore of mKate, a pH-dependent switchable red fluorescent protein. While mKate adopts a fluorescent phenolate cis-state chromophore at physiological pH, substituting the native tyrosine with 3CNY yields a functional protein exhibiting hypsochromically shifted spectral properties. Time-dependent density functional theory (TD-DFT) calculations indicate that 3CNY incorporation results in a trans state at pH 8 but, unlike mKate, is fluorescent. The electron-withdrawing cyano group potentially perturbs conjugation across the chromophore, thus lowering the barrier to cis–trans isomerisation. The trans form may also be stabilised by hydrogen bonds from the cyano group to the rest of the protein. Overall, the introduction of a genetically encoded 3-CNY tyrosine analogue into a fluorescent protein chromophore expands our mechanistic understanding and enables the incorporation of a new chemical tag directly into the chromophore. Full article