Search Results (659)

Caproic acid (CA) production through ethanol-driven chain elongation (CE) is a promising pathway to valorize organic wastes. However, the effect of pH and inoculum source on substrate conversion properties and microbial communities was not fully explored. In this study, performance of caproic acid production with anaerobic methanogenic sludge (AMS), aerobic sludge (AS) and chain elongation sludge (CES) at different pH conditions (uncontrolled (UN), 5, 6, and 7) were investigated. It was found that microorganisms in all inocula could degrade ethanol, but the consumption rate was different. The AS mainly used substrate for biogas production, without CA accumulation, while AMS and CES could synthesize butyrate and caproate with ethanol and acetate as substrates. At pH UN and 5, excessive ethanol oxidation (EEO) was activated and transformed ethanol into acetate resulting in low CA yield. Increasing pH to 7, the AMS produced more caproate and achieved a higher CA yield (0.36 g-COD/g-COD) than that of CES (0.33 g-COD/g-COD). Microbial communities in raw inocula were different, which led to distinct substrate conversion pathways. After fermentation, Anaerolineaceae was the dominate family in AMS, while Corynebacteriaceae and Dysgonomonadaceae dominated in the reactor with CES, explaining the distinct caproate yield in both reactors. The results of this study provided useful information for constructing ethanol-driven CE processes from organic wastes. Full article

Perfluoroalkyl carboxylic acids (PFCAs) are persistent contaminants increasingly subjected to regulatory restrictions. To date, their effects on terrestrial plants remain poorly investigated. To address these knowledge gaps, a comparative assessment was conducted to identify the most sensitive plant species and the most responsive early-growth endpoints. Five PFCAs were selected according to their carbon-chain length (from 3 to 8 C-atoms). Seven plant species were exposed to a wide range of concentrations (from 0.01 up to 100 µg kg⁻¹). Germination and root elongation were evaluated as developmental endpoints to assess both acute and sublethal effects. Across species, germination exhibited weak responses, whereas root elongation appeared to be the most sensitive screening parameter, displaying divergent species-specific patterns. Notably, Sinapis alba and Cucumis sativus emerged as the most responsive species, although they exhibited opposite responses. While mustard exhibited low-dose root stimulation, cucumber showed root inhibition. Interestingly, species within the same family (Brassicaceae and Cucurbitaceae) showed contrasting sensitivity, suggesting that PFCA phytotoxicity is species-specific rather than driven by taxonomic relatedness. This divergent pattern may be linked to distinct morpho-physiological traits, supporting their use as suitable model organisms for phytotoxicity screening of PFCAs. Full article

In this study, 310S austenitic stainless-steel was welded using a laser with varying amounts of Nb to systematically investigate the effect of Nb on solidification cracking susceptibility, mechanical properties, and corrosion resistance of the weld. Under the present experimental conditions, the critical restraint width was higher for the 0.58 wt.% Nb and 1.45 wt.% Nb welds than for the Nb-free and 2.3 wt.% Nb welds, indicating that Nb addition affected the solidification cracking response of the weld. At low-to-moderate Nb contents, Nb can aggravate compositional segregation and increase the presence of low-melting-point liquid films, thereby increasing cracking susceptibility. At higher Nb contents, the reduced cracking susceptibility was accompanied by microstructural refinement and changes in the distribution of Nb-rich constituents during solidification. With increasing Nb content, the number of precipitated phases in the weld increases, mainly distributed at the austenite grain boundaries in granular, elongated, and chain-like forms. The introduction of Nb generally increases the microhardness and tensile strength of the welded joint, attributed to grain refinement strengthening and solid-solution strengthening. The reduction in area first increased and then decreased, suggesting that excessive Nb addition may reduce ductility because of the increased amount of grain-boundary precipitates and local strengthening heterogeneity. With increasing Nb content, the Ir/Ia ratio decreased from 67.6% to 52.2%, suggesting improved intergranular corrosion resistance. This improvement is likely related to the preferential reaction of Nb with carbon, which may suppress the formation of Cr-depleted zones at grain boundaries. Overall, Nb addition improved the corrosion resistance and increased the hardness and tensile strength of the weld; however, its effect on solidification cracking susceptibility was non-monotonic, indicating that careful control of Nb content is required to balance cracking susceptibility, mechanical properties, and corrosion resistance. Full article

Titanium matrix composites (TMCs) are increasingly vital in aerospace for their high specific strength and wear resistance, with compositional gradient design serving as a key strategy to mitigate thermophysical mismatches between ceramic and metal phases. This study utilized laser-directed energy deposition with concurrent wire-powder feeding (LDED-WP) to fabricate TiC/Ti6Al4V gradient composites, employing a laser power of 2700 W, wire feed rates of 110–150 cm/min, and calibrated powder feed rates ranging from 50.22 to 497.13 g/h. Along the build direction, the TiC content was progressively increased from 10 wt.% to 60 wt.%. Investigations into microstructural evolution revealed that the reinforcement morphology transitions from chain-like eutectic TiC to dendritic primary TiC, while the lamellarα-Ti width refines significantly from 4.07 ± 1.15 μm to 0.45 ± 0.29 μm. EBSD analysis confirmed that higher TiC concentrations weaken the characteristic <001> solidification texture, reducing intensity from 11.24 to 7.64. Furthermore, KAM analysis highlighted that thermal expansion and elastic modulus mismatches trigger substantial geometrically necessary dislocation (GND) accumulation at interfaces. Consequently, Vickers hardness improved by 164% along the gradient, peaking at 950 HV. Although the composite achieved an ultimate tensile strength of 630 MPa, the elongation was limited to 2.4% due to crack nucleation in TiC-rich regions and interfacial instability. Full article

The increasing complexity of textile waste, particularly blended fibers, represents a major challenge for conventional recycling approaches. This study proposes a selective valorization strategy for mixed textile waste streams by applying tailored chemical recycling routes to individual fiber type. Preliminary tests identified suitable methodologies for each fiber type: dissolution–precipitation for acrylic (poly(acrylonitrile)—PAN), acidolysis for nylon, glycolysis for polyester (PeS) and acetylation for cotton. Structural characterization confirmed that the incorporation of recycled products did not significantly change the chemical structure or crystallinity of the resulting materials. Furthermore, thermal analysis revealed comparable or slightly improved thermal stability in most recycled systems. Additionally, mechanical performance was observed to vary depending on the polymer type. Recycled acrylic and cellulose acetate showed reduced ductility, while nylon exhibited increased stiffness due to possible recrystallization effects. In contrast, PeS displayed enhanced elongation at break, suggesting increased chain mobility or plasticization effects. Overall, the results demonstrate that selective chemical valorization is a promising route for the efficient recycling of complex textile waste, enabling the recovery of high-quality materials with retained functional properties. Full article

I analyze the nonlinear Hamiltonian equations of motion for a one-dimensional chain of transverse magnetic nano-islands, seeking solutions for different types of static domain walls (DWs) connecting uniform static states. The system of elongated magnetic islands oriented transverse (y-direction) to the chain direction (x-direction) experiences an applied magnetic field transverse to the chain. The macro-spin model includes dipole interactions between islands, their uniaxial and easy-plane anisotropies, and Oersted energy of the applied field. DWs can form most easily between pairs of degenerate uniform states, described by their local magnetizations as oblique, y-parallel, and y-alternating. The DWs between oblique states are well described with scalar ${\phi }^4$ theory. General DW structures are found via a numerical energy relaxation scheme. At some anisotropy and field parameters, nearest-neighbor dipole interactions drive antiferromagnetic order inside the DW itself. Full article

To reduce the environmental impact associated with fossil-based materials, mechanical recycling represents a key strategy, although it inevitably leads to a decline in rheological, thermal, and mechanical properties due to polymer chain degradation. This study investigated the effect of controlled degradation and subsequent reprocessing of polypropylene (PP) using reactive additives from the Nexamite family. Degradation was induced by adding Nexamite R202 at concentrations of 0.5%, 1%, and 2%, while reprocessing was carried out using Nexamite R203 combined with an antioxidant package. The results show that peroxide addition promotes progressive chain scission, leading to reduced thermal stability and mechanical performance. A moderate peroxide content (1%) provided the best balance between improved processability and mechanical performance, showing high ductility and impact toughness. Subsequent reprocessing with Nexamite R203 enabled a significant recovery of the degraded material’s properties. Formulation PP REC 8.2 exhibited increased melt viscosity, slight thermal stabilization, and a marked improvement in elongation at break while maintaining stress values comparable to the starting degraded material. Overall, the results demonstrate that a strategy based on controlled degradation followed by targeted reprocessing can effectively tune processability and partially restore the performance of recycled polypropylene, offering promising opportunities for the upgrading of recycled PP for higher-value applications. Full article

The Lovozero and Khibiny alkaline massifs (Kola Peninsula, Russian Arctic) are the prominent sources of REE minerals, with the Lovozero loparite deposit being the only currently active REE mine in Russia. A new ashcroftine-related mineral phase KA with the idealized chemical formula K₆(Na₄Ca)(Y₈Ca₃Mn)[Si₂₈O₆₈(OH)₂](CO₃)₈F₂·9H₂O was found in the Khibiny alkaline massif. Its empirical formula determined by electron microprobe analysis is Na_4.14K_6.11Ca_3.89Mn_0.59Y_6.10Ce_0.08 Gd_0.32Tb_0.15Dy_0.78Ho_0.19Er_0.35Tm_0.15Yb_0.12Lu_0.06Si₂₈C₈O_93.02F_2.08·9H₂O. The crystal structure was determined and refined by means of single-crystal X-ray diffraction analysis. The KA phase is tetragonal, I4/mmm, a = 24.1661(3), c = 17.5914(4) Å, V = 10,273.4(3) ų. The crystal structure contains two Y sites. The Y1 site is [8]-coordinated and hosts more heavy REEs, whereas the Y2 site is predominantly [7]-coordinated and accumulates lighter REEs and Mn. The crystal structure is based upon the [Si₂₈X₇₀] nanotubes (X = O,OH) elongated along the c-axis and composed of corner-sharing SiX₄ tetrahedra. The external diameter of the tubules is equal to ~19.54 Å, i.e., slightly less than 2 nm. The silicate nanotubes are running parallel to the c-axis and centered along the (00z) and (½½z) directions. The tubules are linked by walls of YO_n polyhedra that also involve triangular CO₃ groups. The K⁺, Na⁺, and Ca²⁺ cations, as well as H₂O molecules, are located either inside or outside the tubules. The crystal-chemical formula of the KA phase can be written as {K_6.14Na_4.30Ca_0.81}[Y_5.88Ca_3.12Dy_0.88Mn²⁺_0.60Gd_0.32 Ho_0.24Er_0.24Tb_0.16Tm_0.16Er_0.12Yb_0.12Ce_0.08Lu_0.08](Mn³⁺_0.09) [Si₂₈O_68.36(OH)_1.65](CO₃)₈F₂·8.97H₂O, which agrees well with the idealized formula. According to the information-based complexity analysis, the KA phase has a very complex structure and belongs to less than 3.5% of the very complex minerals known today. The presence of silicate tubules is the key reason for the exceptional structural complexity of the phase. It is impossible to establish exact relations between the KA phase and ashcroftine-(Y) on the basis of the currently available data, since the last chemical analysis of the latter mineral was done in 1924. Therefore, the mineralogical identity of ashcroftine-(Y) is currently an unresolved problem. The silicate tubule in the KA phase is topologically related to the Linde zeolite A (the LTA zeolite framework) and can be produced from the latter by a series of topological operations. The KA phase forms a homological row with caysichite-(Y) and miyawakiite-(Y), along which the Si content is increasing, and silicate chains in caysichite-(Y) transform into silicate tubules in miyawakiite-(Y) and into silicate nanotubules in the KA phase. Indeed, the M:Si:C ratio (where M = Y, REEs, Ca, Mn, Fe) changes from 1:1:0.75 for caysichite-(Y) through 0.75:1:0.5 for miyawakiite-(Y) to 0.43:1:0.29 for ashcroftine-(Y) (and KA). The increasing role of silica along the row results in the formation of zeolite-derived porous one-dimensional units. The KA phase possesses two important crystal chemical properties that distinguish it from other minerals known to date: it hosts a variety of REEs and is based upon nanoscale zeolite-like silicate units. The KA phase, ashcroftine-(Y), caysichite-(Y), and miyawakiite-(Y) have never been prepared under laboratory conditions. The mineralogical occurrence of the KA phase in the Khibiny massif points out to its secondary origin, i.e., its formation under relatively soft, low-temperature hydrothermal conditions. Thus, the discovery of the KA phase in nature may provide important hints toward its synthesis in the laboratory by means of a soft-chemistry approach. Full article

Deposition of three key 4-alkyl branched-chain fatty acids (KBCFA), including 4-methyloctanoic acid (MOA), 4-ethyloctanoic acid (EOA), and 4-methylnonanoic acid (MNA), causes the gamey flavor in sheep meat. This study integrated metagenomics and metabolomics to evaluate how Allium mongolicum Regel (AMR) supplementation (15 g/d) and rumen fluid transplantation (RFT) modulate rumen microbiota and hepatic metabolism to reduce KBCFA in lamb longissimus thoracis muscle. The experiment consisted of two phases. In Phase I, twelve 3-month-old male Dorper × Small Tailed Han sheep (25 ± 1 kg) were selected as the rumen donor group. These sheep were supplemented with 15 g/d/head of AMR powder in their basal diet until the end of the experiment. In Phase II, thirty 3-month-old male Dorper × Small Tailed Han sheep (23 ± 2 kg) were randomly assigned to one of three groups (n = 10 per group): the control group (STG), which was fed the basal diet and received a physiological saline transplant; the AMR group, which was fed the basal diet supplemented with 15 g/d/head of AMR powder and received a physiological saline transplant; and the rumen fluid transplant group (RTG), which was fed the basal diet and received a rumen fluid transplant from the donor group. Compared to the STG, results showed that the MOA, EOA, and MNA in the AMG decreased by 64.51%, 54.72%, and 49.34%, respectively. Similarly, the MOA, EOA, and MNA in the RTG were reduced by 63.13%, 56.17%, and 49.60%, respectively (p < 0.001). For the rumen metagenome, AMR enriched the genus Prevotella, while RFT increased Butyrivibrio. Hepatic metabolomics revealed a distinct shift where AMR elevated amino acid derivatives and RFT enhanced carnitine-related metabolites. These alterations indicate a potential metabolic shift associated with amino acid metabolism and mitochondrial β-oxidation, rather than lipid elongation. We postulate that this coordinated regulation across the rumen–liver–muscle axis may alter the availability of lipogenic precursors for KBCFA synthesis, ultimately contributing to improved meat flavor. Full article

Trichomes are specialized epidermal structures that play pivotal roles in plant defense against biotic and abiotic stresses. Inositol polyphosphate kinase 2 (IPK2) is a key enzyme in inositol phosphate metabolism with diverse functions in eukaryotic cellular processes. However, its involvement in trichome development remains uncharacterized. Here, we systematically analyzed the function of a rice inositol polyphosphate kinase gene (OsIPK2) in trichome development using transgenic rice lines and heterologously expressing Arabidopsis lines. Scanning electron microscopy (SEM) analysis revealed that OsIPK2 acts as an organ-specific modulator of trichome development in rice. Its overexpression repressed macrohair initiation and microhair elongation in leaves, while promoting trichome development on the glumes. Metabolomic profiling revealed that OsIPK2 overexpression reprogrammed cuticular wax metabolism in transgenic rice leaves, shifting fatty acid flux toward long-chain wax precursors and increasing soluble carbohydrate levels. Transcriptomic and qPCR analysis confirmed that OsIPK2 modulated the expression of genes involved in cuticular wax biosynthesis, auxin homeostasis, and the core trichome regulatory cascade in rice. Conversely, heterologous overexpression of OsIPK2 in Arabidopsis strongly suppressed trichome initiation and branching, resulting in drastically reduced trichome density and fewer trichome branches. These phenotypes were associated with the downregulation of the MYB-bHLH-WD40 (MBW) transcriptional complex and its downstream target genes. Collectively, our findings suggest that OsIPK2 modulated trichome development through organ- and species-specific mechanisms. In rice, it coordinated wax metabolism and the OsSPL10-OsSCR1/2-OsWOX3B-OsHL6 cascade to affect organ-specific trichome formation. In Arabidopsis, it inhibited trichome development by repressing the MBW complex. These results uncover a novel role of OsIPK2 in plant epidermal cell fate specification and advance our understanding of the molecular mechanisms underlying organ- and species-specific regulation of trichome development. Full article

Knot-free timber production in Cunninghamia lanceolata depends critically on internodal characteristics, yet the mechanisms governing internode elongation remain poorly understood, hindering breeding efforts for longer-internode varieties. In this study, we selected two clones with distinct internodal traits (the C1 clone exhibited a 25.03% longer internodal length than the C11 clone) as materials. Enzyme-linked immunosorbent assay (ELISA) and RNA sequencing were used to investigate dynamics in endogenous hormones and transcriptional regulation in internodal growth. Results showed that the difference in indole-3-acetic acid (IAA) rhythms in apical buds is a key factor of C1’s longer internodal growth; higher levels of IAA and cytokinins in the apical buds of C1 may support sustained internodal growth; upregulated IAA-related genes in upper phloem (PIN1 and SAURs), which are involved in polar transport and signal response, indicates a stronger capacity to establish apical dominance. Hormone transport may be regulated by very long-chain fatty acids (VLCFAs). Consistent with reduced brassinosteroid activity, genes involved in VLCFA biosynthesis and transport were generally lower in C1, implying excessive VLCFA accumulation in C11 may be negative to IAA transporting and internode growth. This study offers a preliminary insight into internodal growth mechanisms influenced by hormone biosynthesis and transport in C. lanceolata., providing a basis for genetic improvement, germplasm selection, and exogenous hormone applications in knot-free timber cultivation. Full article

This study investigates a thermal management strategy for butyl/chloroprene rubber (IIR/CR) bladder compounds by incorporating hexagonal boron nitride (h-BN) as a thermally conductive filler to enhance heat transfer efficiency. Compounds containing 0, 10, 25, and 33 wt% h-BN were prepared via solution mixing to ensure uniform dispersion and subsequently vulcanized using a hot press. The materials were characterized in terms of morphology, cure behavior using a moving die rheometer (MDR), thermal conductivity, crosslink density, mechanical properties, and dynamic mechanical analysis (DMA). The incorporation of h-BN significantly enhanced thermal performance, nearly doubling the thermal conductivity at 33 wt%. MDR measurements demonstrated that this improved heat transfer capability accelerated the thermal onset of vulcanization, effectively reducing scorch time. Mechanical testing revealed a systematic increase in stiffness at application-relevant low strain levels (25–50%), attributed to hydrodynamic reinforcement, accompanied by a progressive increase in elongation at break. This enhanced extensibility is associated with the presence of lamellar h-BN platelets, which facilitate stress redistribution and promote dynamic chain mobility under deformation. DMA showed that h-BN incorporation increased the storage modulus and intensified the Payne effect, confirming the formation of a robust physical filler network. Overall, the incorporation of h-BN delivers a formulation pathway for energy-efficient tire curing bladders by significantly improving heat transfer efficiency and dimensional stability. Full article

To investigate the inevitable aging of composite insulators under the coupled effects of electrical, thermal, ice, and fog stresses, as well as to explore their aging mechanisms and residual strength prediction methods, this study collected operational insulator samples from four environmental regions: Tibet, Yunnan, Hunan Xuefeng Mountain, and Anhui/Chongqing. Mechanical properties, including tensile strength, elongation at break, and shear resistance, were tested. The results indicate that the degradation of mechanical performance in composite insulation components can be attributed to the synergistic interaction of operational environments and material characteristics, with the aging behavior of high-temperature vulcanized (HTV) silicone rubber exhibiting significant non-linearity. Based on existing research, molecular dynamics simulations were employed to construct microstructural models at different aging stages, and it was verified that main chain scission, reduced system density, and changes in the elemental chemical environment during aging are closely related to the degradation of material mechanical properties. Based on hyper-elastic constitutive theory and fracture mechanics, a quantitative method for assessing the comprehensive aging degree was proposed, with “service years” and “operational altitude” as the core dimensions. A negative exponential model was established to describe the strength degradation of silicone rubber materials. This model enables the non-destructive estimation of the residual mechanical strength of in-service insulators in complex regions without power interruption, providing a decision-making framework for grid operation and maintenance. Full article

Rapeseed (Brassica napus L.) is a globally important oilseed crop; however, its ‘double-low’ cultivars exhibit substantially reduced glucosinolate levels in vegetative tissues. To investigate whether UV-B radiation could be used to enhance glucosinolate accumulation, we systematically examined the modulation of glucosinolate profiles and associated biosynthetic pathways in leaves of the ‘double-low’ cultivar NY4 under white light (WL) supplemented with two UV-B intensities: low-intensity UV-B (UVBL, 0.1 W m⁻²) and high-intensity UV-B (UVBH, 0.4 W m⁻²). Rapeseed seedlings were treated for 21 days under a 16 h photoperiod, and leaf samples were collected at the end of the treatment period, with three biological replicates per condition. Compared with the WL control, UVBL significantly increased total glucosinolate content by 64.57%, driven predominantly by elevated accumulation of progoitrin and neoglucobrassicin. In contrast, UVBH reduced total glucosinolate levels but markedly elevated gluconasturtiin content. Transcriptome analysis revealed that UVBL upregulated key genes involved in glucosinolate biosynthesis (e.g., MAM, IPMDH, CYP79F1, and SOT17/18) and transcription factors (e.g., MYB28, MYB34, MYB51, and MYB122). Conversely, UVBH downregulated genes associated with side-chain elongation of aliphatic glucosinolates and secondary modification of indolic glucosinolate. Collectively, these results demonstrate that low-intensity UV-B radiation can effectively boost total glucosinolate content in rapeseed leaves via transcriptional reprogramming. Full article

We synthesized two vitamin D₃ analogues, 3 and 4, which have a shortened or elongated fluoro-side-chain based on 24,24-difluoro-25-hydroxyvitamin D₃ (5) using an efficient convergent approach and studied their preliminary biological activity. Both analogues exhibited greater resistance to CYP24A1-mediated metabolism than the natural 25-hydroxyvitamin D₃ (6), although their stability was lower than that of 5. Analogue 3 showed an approximately 100-fold lower human vitamin D receptor (hVDR)-binding affinity compared with 5 and 6. Despite this marked reduction in VDR-binding affinity, it demonstrated an approximately 1.5-fold increase in VDR-ligand binding domain (LBD) transcriptional activation of the natural ligand 6. In contrast, analogue 4 displayed moderate VDR-binding affinity and VDR-LBD transactivation compared with 5 and 6. We found that compound 3 is a unique vitamin D analogue with a fluorinated and shortened side-chain, exhibiting low binding affinity for hVDR but potent transcriptional activity through VDR-LBD with its long half-life; thus, 3 may serve as a basic structural skeleton for advancing medicinal chemistry and drug discovery. Full article