Search Results (656)

The Mediterranean Basin ranks among the region’s most vulnerable to climate change, yet little evidence exists as to whether the scientific literature emphasises strategic planning or operational implementation. This study measures the thematic distribution of adaptation strategies in the Mediterranean adaptation literature and identifies which categories of measures remain comparatively under-researched. A systematic review following PRISMA 2020 was conducted on peer-reviewed articles indexed in the Web of Science Core Collection and published between 2015 and 2024, retrieved through a thematic query built on regional and landscape planning vocabulary. Of 89 articles retained in the qualitative synthesis, 64 reported at least one codable adaptation measure and entered the quantitative analysis, yielding 123 coded occurrences across twelve thematic categories; the remaining 25 returned a null coding vector. Chi-square goodness-of-fit testing against a maximum-entropy benchmark, with residuals corrected for article-level dependence by cluster bootstrap and for multiplicity by the Benjamini–Hochberg procedure, shows an uneven distribution (χ² (11, N = 123) = 56.02, p < 0.001; Cramér’s V = 0.20; Pielou’s evenness J = 0.90). Sustainable development and adaptation policy are over-represented; green spaces, cultivation and hydrological interventions are under-represented. An article-level analysis of register co-occurrence finds no segregation between policy-oriented and technical categories: 34.4% of coded articles engage both registers, and the two are statistically independent across the corpus (odds ratio 2.02, p = 0.17). The imbalance is therefore one of volume rather than of community structure. Because the unit of observation is the published article rather than the implemented intervention, and because the corpus is restricted to planning-oriented, English-language, indexed literature dominated by northern-rim EU member states, these findings characterise the orientation of a defined body of literature and cannot establish a gap in adaptation practice. The study provides a reproducible method for measuring thematic emphasis and an empirical basis for identifying under-researched categories of operational adaptation measures. Full article

Background: Biallelic loss-of-function variants in LAMC3, encoding laminin gamma-3, cause occipital cortical malformation (OMIM#614115). White matter disease and intracranial neoplasia have not been reported in this spectrum. We report a novel homozygous LAMC3 frameshift variant, expanding its phenotypic and molecular spectrum. Methods: Two adolescent siblings from a consanguineous Turkish family underwent whole-exome sequencing, with segregation confirmed by NGS/IGV and classification per ACMG/AMP criteria. In silico analyses included multiple sequence alignment, AlphaFold modeling of wild-type and mutant proteins, and docking against nidogen-1 (NID1). Results: Both siblings had a novel homozygous LAMC3 variant frameshift variant (NM_006059.4: c.1852_1882del; p.(Pro618Serfs*5)), classified as pathogenic (PVS1, PM2, PP3, PP1) with full cosegregation. Proband II.III, a 17-year-old female, developed postoperative epilepsy after resection of a tectal low-grade glioneuronal tumor harboring a somatic KRAS (NM_004985.3) p.(Gln61Lys) variant (VAF 42.9%), with periventricular white matter gliosis. Proband II.IV, a 15-year-old male, presented with confluent leukoencephalopathy, occipital pachygyria, parietal polymicrogyria, and subcortical band heterotopia, illustrating striking intrafamilial discordance. Conclusions: Docking analysis revealed that the cleavage removes the C-terminal nidogen-binding region, eliminates the predicted wild-type interface (residues 906–1029), and shifts the binding to an unnatural N-terminal surface. This finding is a hypothesis-generating result consistent with loss of function. This study expands the LAMC3 phenotype to include leukoencephalopathy and reports a co-occurring low-grade tectal glioneuronal tumor as a novel, single-case observation, supporting inclusion of LAMC3 in the differential diagnosis of pediatric leukoencephalopathies, particularly with consanguinity. Full article

The microstructural evolution and mechanical properties of cast and sintered CrMnFeCoNi high-entropy alloys during cold rolling and subsequent annealing were investigated. The as-cast alloy exhibited columnar grains with elemental segregation and Mn-oxide particles, whereas the as-sintered alloy exhibited much finer equiaxed grains with annealing twins and fine Cr/Mn-oxide particles. After cold rolling, the sintered alloy exhibited a higher density of fine shear bands (SBs) and a larger fraction of dynamically recrystallized grains formed along the SBs. Partial static recrystallization occurred during annealing at 600 °C, with a significantly higher recrystallized fraction in the sintered alloy. The enhanced formation of fine SBs in the sintered alloy promoted both dynamic and static recrystallization. Complete static recrystallization was achieved after annealing at 700–900 °C. Compared with the cast alloy, the sintered alloy exhibited coarse recrystallized grains after annealing at 600, 700, and 800 °C but finer grains after annealing at 900 °C. The sintered alloy exhibited lower strength after annealing at 700 °C but higher strength after annealing at 900 °C. Yield strength modeling indicated that grain boundary and oxide dispersion strengthening governed the yield strength of the annealed alloy. The different microstructural evolutions during cold rolling and annealing and the resulting mechanical properties of the cast and sintered alloys are further discussed. Full article

Induced pluripotent stem cells (iPSCs) are prone to genomic instability during prolonged culture, with recurrent chromosomal aberrations conferring selective advantages. Replication stress is a major driver of this instability, yet the repertoire of replication stress-sensitive loci in iPSCs remains largely unexplored. Here, we mapped aphidicolin-sensitive fragile sites (asFS) in three independent iPSC lines using classical cytogenetic break analysis combined with Monte Carlo simulation and MiDAS mapping directly on banded metaphase chromosomes. We identified 28 asFS, which segregated into a highly active Major cluster (8 sites, accounting for 59% of breaks among asFS) and a less active Minor cluster (20 sites). Five universal asFS (9p21, 6q25-26, 20p11-12, 10q22, Xq25) were present in all three lines, representing a fragility signature associated with the pluripotent state, with Xq25 shifting into the Major cluster after correction for X chromosome dosage. Minor asFS showed preferential co-localization with physical breakpoints or minimal overlapping regions of recurrent culture-acquired aberrations, including 20q11.21 (BCL2L1), 1q32 (MDM4), 8q24 (MYC), 17q21 (WNT3-WNT9B), and 18q21 (DCC/FRA18B). MiDAS mapping validated most asFS and revealed additional replication stress-sensitive loci in pericentromeric and subtelomeric regions that are difficult to score by conventional G-banding. Comparison with fragile site maps from other cell types revealed that the iPSC asFS repertoire is distinct in rank order and relative activity, characteristic of the pluripotent state. Collectively, our findings indicate that the asFS repertoire in iPSCs is hierarchically organized into a stable universal core and a variable peripheral component, and suggest that Minor asFS may contribute to, or be associated with, the genesis of culture-acquired rearrangements. This work provides a framework for understanding how replication stress and clonal selection shape the mutational landscape of pluripotent stem cells. Full article

The potential of clay as a replacement for Portland cement in the manufacture of injection cement–clay mortars (ICCMs) for soil stabilization is examined in this investigation. The objective of this study is to produce environmentally friendly injection-molded mortars for soil stabilization based on Portland cement (PC) and clay (C). Experimental ICCMs with C contents ranging from 0% to 50% without the addition of microsilica (MS) and ICCMs with C contents ranging from 0% to 50% and 2% MS were produced. The evaluation included the density, water segregation, and cone spread diameter of fresh ICCMs, alongside the density, flexural strength, and compressive strength of hardened ICCMs. The findings indicated that as C content rose from 0% to 50%, fresh mortars experienced a decrease in density, flowability, and water segregation. Hardened mortars exhibited reduced density, compressive strength, and flexural strength as C content increased. Modifying mortars with MS has a positive effect on their strength properties. The reduction in flexural and compressive strength for mortars with 50% C was 54.2% and 60.1%, respectively, while for similar mortars with 2% MS, the reduction in strength was 47.9% and 51.8%, respectively. ICCM soil stabilization compositions modified with MS are the most effective in comparison with similar compositions without MS and have a homogeneous structure with pores, microcracks, and hydration reaction product zones. The optimal ratios of raw components for the production of ICCMs for soil stabilization were determined: a water–solid ratio of 0.6, PC content from 90% to 50%, C content from 10% to 50%, and an MS content of 2% of the dry component weight. This research contributes to sustainable development by reducing CO₂ emissions per 1 m³ of mixture production by up to 47.8% and by using raw materials rationally. Full article

Heavy metals (HMs) and rare earth elements (REEs) increasingly co-occur in environmental waste streams and soils, yet their comparative neurotoxic mechanisms and sublethal effects on invertebrate decomposers remain poorly understood. This study used black soldier fly larvae (BSFL, Hermetia illucens) to perform a comparative behavioral and transcriptomic assessment of 23 HMs and 16 REEs across two acute exposure concentrations. High-throughput video tracking and phenomic analysis showed HMs produced broader disruption than REEs, with low-concentration HMs inducing locomotor suppression, thigmotaxis, reduced fractal dimension and entropy, progressing to severe motor inhibition and rigid low-entropy states. In contrast, REEs showed a biphasic profile, shifting from selective locomotor suppression with preserved organization at low concentrations to hyperactive, fragmented, high-entropy movement with increased thigmotaxis at high concentrations. PCA and hierarchical clustering integrated endpoints into four neurobehavioral fingerprints segregating metal class and concentration, with partial overlap of high-concentration REEs with HMs along a shared high-toxicity axis. Transcriptomic profiling showed that cobalt as a representative HM activated DNA damage and cell-cycle pathways, perturbed energy signaling, and suppressed neuroactive ligand–receptor interaction, whereas samarium as a representative REE downregulated xenobiotic metabolism, oxidative phosphorylation, glutathione metabolism, and synaptic vesicle cycling. These findings demonstrate distinct concentration-dependent neurotoxic modes of action for HMs and REEs and establish BSFL behavioral phenomics integrated with transcriptomics as a mechanistically informative platform for ecological risk assessment in contaminated waste systems. Full article

Background/Objectives: Contiguous Xq26.2 deletions involving FRMD7 and IGSF1 are rare and incompletely characterized. FRMD7 loss causes X-linked idiopathic infantile nystagmus (IIN), whereas IGSF1 loss causes central hypothyroidism and other pituitary-related abnormalities. We aimed to define the clinical and molecular spectrum of an Xq26.2 contiguous gene deletion in a large Bedouin kindred with infantile nystagmus. Methods: We clinically evaluated ten family members (3 males and 7 females); genomic analyses included chromosomal microarrays, whole-exome and whole-genome sequencing, breakpoint PCR, and Sanger sequencing. Results: We identified a novel 1.44-Mb Xq26.1-q26.2 deletion, NC_000023.11:g.130756102_132199443del (GRCh38), encompassing complete loss of FRMD7, IGSF1, ARHGAP36, OR13H1, and STK26 and partial deletion of the 5′ end of ENOX2. The deletion was molecularly confirmed in six family members. The kindred exhibited a broad phenotypic spectrum, from an asymptomatic confirmed female carrier to isolated nystagmus and combined ocular–endocrine manifestations. Nystagmus was highly penetrant, whereas endocrine abnormalities were less frequent and variable. Hypoprolactinemia occurred in one confirmed female carrier, and a confirmed hemizygous boy had low-normal free T4 without overt central hypothyroidism. The only relative with overt central hypothyroidism was not genotyped; therefore, co-segregation could not be established. Conclusions: These findings further delineate the clinical spectrum of Xq26.2 deletions, highlight marked intrafamilial variability, and support structural variant analysis in unexplained IIN and/or endocrine abnormalities. Longitudinal endocrine assessment of individuals with Xq26.2 deletions and at-risk relatives in affected families may enable early detection and treatment of hypothyroidism. Full article

Located 30 km south–southeast of Kabul in Logar province, Aynak is the largest and best-known copper orebody in Afghanistan. The deposit is hosted by the Loy Khwar Formation, a Neoproterozoic–Cambrian metasedimentary sequence of dolomite marble, carbonaceous quartz schist and quartz–biotite–dolomite schist. The primary ore minerals are chalcopyrite and bornite, with less abundant pyrite and minor cobaltite, chalcocite, pyrrhotite, sphalerite and molybdenite. Sulphides occur as bedded laminae and disseminations, in metamorphic segregations, and in syn- to post-metamorphic cross-cutting veins. Building on the mineralogical, lithogeochemical and sulphur isotope framework established by Waizy et al. (2020), ICP-MS analyses of sulphide-rich separates from Central and Western Aynak (n = 31) were undertaken to characterise trace-element distributions, evaluate possible metal sources, and further constrain the genetic model of the deposit. Co and As enrichment in chalcopyrite-dominant samples is consistent with cobaltite, whereas Co enrichment in the absence of arsenic suggests the possible presence of carrollite. Fluid inclusion analyses of secondary quartz-hosted inclusions indicate interaction between the Aynak deposits and saline aqueous fluids (32 to 47 equivalent wt% NaCl) at minimum P-T conditions of ~100–200 MPa and 300 °C. It is uncertain whether these fluid parameters relate to primary copper transport and deposition, or to remobilisation during metamorphism. Nevertheless, comparison with analogous sediment-hosted copper deposits suggests that highly saline basinal brines played an important role in the formation and evolution of the deposit. Occurrences of scapolite provide additional evidence for a model of brine-related mineralisation. Together with previously published mineralogical, lithogeochemical and sulphur isotope evidence, these findings support a sedimentary–diagenetic origin for the Aynak copper deposit that is broadly comparable with sediment-hosted stratiform copper systems of the Central African Copperbelt. Full article

Reversible solid oxide cells (ReSOCs) represent one of the most promising electrochemical technologies for sustainable energy conversion and storage, yet their large-scale deployment remains constrained by electrode materials capable of sustaining stable performance under alternating oxidizing and reducing conditions. Reversible solid oxide cells require electrode materials that combine phase stability, chemical compatibility, redox tolerance and a microstructure suitable for gas transport and surface reactions. However, the relationships among cation composition, thermal processing, phase formation and local chemical homogeneity remain insufficiently understood, particularly for compositionally complex perovskite-related oxides. In this work, this problem was addressed through a comparative physicochemical screening of three candidate electrode materials synthesized by a simple co-precipitation route: two co-doped lanthanum ferrites, (La_0.8Sr_1.2) (Fe_0.9Co_0.1)O_6+δ (LSFC) and (La_0.8Ca_1.2) (Fe_0.9Co_0.1)O_6+δ (LCFC), and one high-entropy praseodymium nickelate, Pr(Ba_0.8Ca_0.2)(Fe_0.2Co_0.2Ni_0.2Cu_0.2Zn_0.2)₂O_6+δ (PBC-HEO). DTA–TG analysis was used to determine the thermal decomposition and crystallization ranges of the precipitated precursors. Phase evolution as a function of calcination temperature was investigated by X-ray diffraction, while Raman and FTIR spectroscopy were employed to examine the local metal–oxygen environment and structural disorder. Raman spectroscopy confirmed the formation of perovskite-type metal–oxygen frameworks in all samples and revealed distinct redistributions of spectral weight between apical/equatorial (or symmetry-related) BO₆ stretching sub-modes and bending/tilting modes, reflecting different local defect-chemical mechanisms associated with A-site doping (Sr vs. Ca) in the Ruddlesden–Popper ferrites and B-site multi-cation occupancy in the double-perovskite PBC-HEO. Bulk and local elemental compositions were assessed by ICP-MS and SEM-EDS, respectively, and SEM was used to compare particle morphology and porosity. SEM-EDS analysis showed that PBC-HEO developed the most open and interconnected microstructure among the investigated powders, although accompanied by residual compositional heterogeneity. This morphology may favor gas accessibility; however, its effective impact on electrocatalytic performance requires dedicated surface area, porosimetry, electrical, and electrochemical measurements. LSFC formed a single major Ruddlesden–Popper phase only after high-temperature calcination, whereas LCFC retained calcium-containing secondary phases. PBC-HEO developed a major perovskite-related phase at 700 °C, accompanied by minor Zn-rich segregation. Under the selected processing conditions, PBC-HEO retained the finest and most interconnected porous microstructure, although it also displayed the highest local compositional heterogeneity. These results demonstrate that cation selection and thermal history jointly control phase stability, local disorder and microstructure, providing a basis for the subsequent electrochemical evaluation and optimization of perovskite-related ReSOC electrode materials. Full article

Cycling infrastructure has emerged as a strategic lever for sustainable urban development in Latin America, yet the factors that determine its effectiveness remain poorly understood and dispersed across fragmented literature. This systematic review, conducted in accordance with PRISMA 2020 guidelines, synthesizes evidence from 16 peer-reviewed studies published between 2020 and January 2026 to identify the key determinants of cycling infrastructure effectiveness in Latin American cities. Five critical dimensions emerged from the analysis: physically segregated infrastructure, gender-responsive design, multimodal connectivity, environmental and public health co-benefits, and adaptation to topographical and climatic conditions. The evidence reveals that segregated bike lanes increase cycling uptake by 48–187%, multimodal integration boosts combined trips by approximately 34%, and gender-sensitive interventions increase female cycling participation by up to 89%. These findings converge on a central insight: infrastructure effectiveness is not achieved through isolated investments but through the coherent, simultaneous implementation of multiple interconnected dimensions. This review contributes an original multidimensional analytical framework to guide evidence-based public policy and investment in sustainable urban mobility across the region. Full article

Background: Nephrogenic diabetes insipidus (NDI) is a rare disorder characterized by renal resistance to arginine vasopressin, most commonly caused by pathogenic variants in the AVPR2 gene. While X-linked NDI classically affects males, heterozygous females may exhibit variable clinical expression. Certain AVPR2 variants are associated with partial NDI and milder phenotypes. Methods: We conducted a retrospective family study of a multigenerational Greek pedigree with suspected hereditary NDI. Clinical, biochemical, and pedigree data were collected through chart review and family interviews. Genetic analysis was performed using whole-exome sequencing, and variant interpretation followed ACMG/AMP guidelines. Results: Fourteen individuals across four generations were evaluated. Molecular analysis identified a familial AVPR2 (NM_000054.7):c.964C>T (p.Pro322Ser) missense variant in three males and three females, with obligate carrier status inferred in two deceased females, segregating in an X-linked pattern. Hemizygous males exhibited a broad phenotypic spectrum, ranging from partial NDI with later onset to severe early-onset disease with urinary tract complications. Heterozygous females showed variable expression, from asymptomatic carriers to mildly symptomatic individuals. The variant co-segregated with disease and, based on ACMG criteria, it was classified as pathogenic. Conclusions: In our family, the AVPR2 c.964C>T (p.Pro322Ser) variant was associated with a remarkably broad clinical spectrum, ranging from asymptomatic heterozygous females to severe early-onset disease with urinary tract complications in affected males. These observations emphasize the need for early molecular diagnosis, systematic evaluation of female carriers, and long-term surveillance to prevent disease-related complications and optimize genetic counselling. Full article

This study investigates the nanomechanical response of aluminum substrates coated with crystalline or amorphous equiatomic FeNiCrCo compositionally complex alloy (CCA) layers using molecular dynamics nanoindentation. We evaluated the influence of coating microstructure and pre-relaxation via Monte Carlo/molecular dynamics (MC/MD) on deformation behavior at shallow (35 Å) and deep (65 Å) indentation depths. The relaxation process is critical for equilibrating internal stresses and homogenizing the initial stress field in amorphous phases, while preventing chaotic defect multiplication in crystalline lattices, yet it simultaneously promotes Fe and Cr surface segregation consistent with the equilibrium chemical short-range ordering of the alloy. The results reveal distinct deformation mechanisms: crystalline coatings exhibit higher peak indentation forces of about 300 ± 16 eV/Å characterized by discrete force fluctuations indicative of localized plastic events, while amorphous coatings show lower peak loads (~170–220 ± 12 eV/Å), corresponding to a reduction in load-bearing capacity of roughly 25%–40%, and smooth, continuous deformation governed by shear transformation zones. Notably, in amorphous systems, pressure-induced local crystallization occurs under load, with ordered FCC/HCP regions persisting after unloading, indicating partial irreversibility of the phase transition. Upon deep indentation into the substrate, the amorphous system exhibits a sharp increase in stiffness due to substrate compaction, whereas the crystalline system maintains high load-bearing capacity with reduced defect density in the relaxed state compared to the non-relaxed counterpart. Relaxation significantly reduces force-curve fluctuations in both systems, enhancing the stability of the mechanical response. Compared with uncoated aluminum, which exhibits extensive twin propagation and deep defect penetration, the FeNiCrCo-coated systems approximately halve the defect penetration depth and reduce the defective-atom volume fraction in the substrate by about a factor of two, thereby more effectively confining plastic deformation and preserving substrate integrity under the simulated conditions. These findings demonstrate that the synergy between coating crystallinity and rigorous relaxation protocols governs stress distribution patterns—localized hotspots in amorphous phases versus extended networks in crystalline ones—providing key insights for designing advanced protective coating–substrate systems with optimized mechanical performance. Full article

This study systematically investigated the effects of Co/Ni ratios (0.6–2.0) on the solidification behavior, as-cast microstructure, and element segregation of Co-Al-W-based superalloys, and elucidated the mechanism of thermodynamic and kinetic synergistic regulation. The results show that increasing the Co/Ni ratio has a negligible effect on the liquidus and solidus temperatures, but it significantly lowers the dissolution temperature of the γ′ phase, thereby expanding the alloy’s heat treatment window (HTW) from 215 °C to 269 °C. As the Co/Ni ratio increased from 0.6 to 2, the SDAS at the center of the alloy ingot decreased from 112.4 μm to 43.3 μm, resulting in a significant refinement of the as-cast microstructure. The dendritic segregation coefficients for positively segregating elements such as Ta, Hf, and Al, as well as negatively segregating elements such as W, all approached 1 significantly, effectively suppressing microsegregation during solidification. This study reveals the multidimensional synergistic regulation mechanism of the Co/Ni ratio on the non-equilibrium solidification behavior of highly alloyed Co-Al-W-based superalloys and quantitatively elucidates the relationship between the Co/Ni ratio, the microstructural uniformity of as-cast specimens, and the heat treatment process window. For the first time in a highly alloyed multi-component Co-Al-W system, a correlation has been established between the Co/Ni ratio, element segregation, dendrite coarsening coefficient, and heat treatment window. Full article

Tritium breeding blanket is a key component of future fusion power plants, and its performance depends on the selection, fabrication, and qualification of lithium-based ceramic material. Among the proposed lithium ceramics materials, the main candidates for ceramic breeders are lithium orthosilicate (Li₄SiO₄) and lithium metatitanate (Li₂TiO₃). These advanced ceramics and their biphasic composites are the leading candidates due to their high lithium density, favorable tritium breeding ratio (TBR ≈ 1.15–1.25 with Be₁₂Ti multiplier and 90% ⁶Li enrichment), and robust thermo-mechanical behavior within the 200–900 °C operational window of helium-cooled pebble bed (HCPB) blankets. This review provides an engineering-oriented assessment covering fabrication routes (solid-state, hydrothermal, melt-based, drip casting, powder injection molding, microwave sintering, and digital light processing additive manufacturing); microstructure–property relationships and performance under neutron irradiation; and tritium generation, retention, and release as functions of chemical composition, defect structure, and operating temperature. Induced radioactivity of Li-based ceramics and key impurity elements is quantified using activation formalisms applied to WWR-K reactor conditions, providing guidance for raw-material selection and waste-management assessment. Authors’ original contributions include (i) an empirical model of pebble crush load vs. biphasic composition (R² > 0.99); (ii) two universal semi-empirical kinetic models (exponential growth and non-linear strength degradation, R² = 0.97–0.99) for nine structural and mechanical parameters of Li₂TiO₃ under He²⁺ and H⁺ irradiation; (iii) a consolidated table of Arrhenius tritium diffusion parameters from reactor experiments and DFT; and (iv) an induced radioactivity calculation for the biphasic system with two-exponential post-irradiation decay analysis. The review identifies biphasic Li₄SiO₄–Li₂TiO₃ composites with ~30 ± 5 mol.% Li₂TiO₃ as particularly promising and formulates specific data gaps and modeling needs for the reliable deployment of ceramic breeder pebbles in helium-cooled fusion blanket systems. It should be specifically noted that Li₄SiO₄ pebbles fabricated via the melt method, as an example, typically exhibit exceptionally high densities, generally exceeding 90% of the theoretical density (TD). Building on the calculation of induced radioactivity, it is crucial to consider the microstructural distribution of highly radioactive nuclides (e.g., Co, Mn) within the ceramic matrix. If these impurities segregate at grain boundaries rather than being homogeneously distributed, there is a potential pathway to develop targeted wet-chemical methods, such as selective acid leaching, to remove these impurities post-irradiation, thereby lowering the waste disposal classification. Full article

Cyanobacteria are increasingly recognised as photosynthetic chassis for sustainable metabolic engineering because oxygenic photosynthesis generates ATP and NADPH via the photosynthetic electron transport chain, which drive CO₂ fixation through the Calvin–Benson–Bassham cycle into carbon intermediates that can be redirected toward engineered heterologous pathways. Their genetic tractability, CO₂-fixing capacity, ecological adaptability, and relatively simple cellular organisation make them attractive platforms for developing low-carbon biotechnological processes. This review explores recent progress in engineering cyanobacteria for heterologous pathway construction, critically evaluating genetic tools including transformation methods, genome integration strategies, promoter systems, and CRISPR-based editing, with specific emphasis on challenges of direct relevance to phototrophic chassis: host–pathway metabolic compatibility, precursor supply, cofactor balancing between photosynthetic output and heterologous pathway demand, and achieving genetic stability in polyploid cyanobacterial genomes. The review also addresses key limitations with mechanistic context: metabolic burden from multi-gene pathway expression reduces growth rate and selects against producing cells; polyploidy delays complete chromosomal segregation of engineered constructs; slow photoautotrophic growth constrains volumetric productivity; native regulatory networks resist carbon flux redirection; and cultivation constraints—including light attenuation in dense cultures and mismatches between photosynthetic ATP/NADPH supply and heterologous pathway demand—further limit achievable yields. Full article