Search

The increased pollution of water resources by toxic heavy metals poses a huge threat to the aqueous ecosystem. Since the low concentrations of heavy metals are often highly toxic but difficult to remove, novel efficient adsorbents still need to be explored. Herein, the superparamagnetic thiol-functionalized oxygenous carbon nitride nanocomposite (CNO/Fe 3 O 4 -SH) with multifunctional groups such as –NH 2 , –OH, –SH, and –COOH was fabricated by a simple and eco-friendly method. The maximum adsorption capacities of Pb2+, As3+, and Cd2+ ions on CNO/Fe 3 O 4 -SH at pH = 6 were 80.79, 71.78 and 66.19 mg/g, respectively, when their equilibrium concentrations were 20 mg/L. Under the equilibrium concentration below 0.01 mg/L, the adsorption capacities of these heavy metals over CNO/Fe 3 O 4 -SH were much higher than those of other adsorbents. The competitive adsorption investigations showed that the adsorption order in polymetallic solutions was Pb2+ > As3+ > Cd2+. Adsorption kinetics and isotherms studies indicated that the adsorption of Pb2+, As3+ and Cd2+ by CNO/Fe 3 O 4 -SH was attributed to monolayer adsorption and the adsorption process was controlled by chemical adsorption. The thermodynamic experiments showed that the adsorption processes were spontaneous and endothermic. After six adsorption/desorption cycles, CNO/Fe 3 O 4 -SH maintained its original morphology and adsorption ability, indicating its excellent regeneration performance, which had significant potential application in the decontamination of trace heavy metal ions in water. [Display omitted] • Thiol-functionalized oxygenous carbon nitride was prepared for heavy metal removal. • CNO/Fe 3 O 4 -SH had high adsorption capacity at low concentrations of heavy metals. • Separation and regeneration of CNO/Fe 3 O 4 -SH was very simple and efficient. [ABSTRACT FROM AUTHOR]

Pickering emulsions stabilized by cellulose nanofibrils (CN) have sparked significant attention, however the fundamental mechanisms underpinning the stabilization process remain insufficiently elucidated. Focusing on an academic debate of surface charge's contribution to stabilization, this study first explored how the varying carboxyl group contents of TEMPO-oxidized CN (TCNs) impacted Pickering emulsions' formation and stability. TCNs with 662 μmol/g carboxyl groups exhibited distinctive attributes, including larger particle sizes (322 nm in length), improved thermal stability (maximum decomposition temperature of 317 °C), and increased viscosity (1.57 Paִִ⋅s) compared to their counterparts with 963–1011 μmol/g charge density. Notably, the former one, with a larger three-phase contact angle (51.5°), higher interfacial tension, and greater detachment energy (21.69 × 10−18 J), resulted in a homogeneous dispersion of spherical oil droplets and super-stable Pickering emulsions with a consistent emulsifying index of 100% over 30 days. These findings clearly clarified that TCNs with a lower charge density exhibit superior emulsifying properties. In addition, for the first time, a distinct oil droplet-decorated fibrillar structure was observed, probably suggesting that TCNs might be able to serve as anchoring matrixes to guide the distribution of oil droplets. These structures seemed to impeded the migration and accumulation of the oil droplets, consequently enhancing the stability of the resulting Pickering emulsions. To sum, this study clearly elucidated the role of surface charge in stabilizing cellulose-based Pickering emulsions and proposed a new model to expound the cellulose-oil interaction mechanisms, thus providing new theoretical and practical insights on utilization of CN as highly effective emulsifier for super-stable food-grade Pickering emulsions. [Display omitted] • TEMPO-oxidized nanofibrils (TCNs) are effective to stabilize Pickering emulsions. • Clarify surface charge's contribution and further understand stabilization mechanism. • Relatively low charge density instead of high charge density for better stability. • Distinct oil droplet-decorated fibrillar structures enhance emulsion's stability. [ABSTRACT FROM AUTHOR]

Radial Plastic Flow Machining (RPFM) is a novel severe plastic deformation process. By designing a specific plastic flow channel, the material is allowed to flow radially into the predetermined channel under the combined action of extrusion and cutting. A restricting ring is placed in the channel to form a copper terminal structure in one step. This study investigates in detail the formation mechanism, mechanical properties, and thermal stability of gradient structured copper terminals generated under different extrusion angles. It was found that as the extrusion angle increased, the high strain region slightly decreased, while the low strain region increased, allowing more material to be radially extruded. This indicates that tensile strength and toughness can be balanced by controlling different extrusion angle parameters. In performance testing, the study showed that the hardness of the copper terminals prepared by RPFM was more than double that of the original copper material, and the maximum tensile strength also doubled. Moreover, the performance of the copper terminals annealed at 150 ∘ C was similar to that of untreated copper terminals, demonstrating good thermal stability at this temperature. The study suggests that RPFM is not only an effective process for manufacturing gradient structured copper terminals in one step, but it also provides a new method for manufacturing copper terminals with excellent comprehensive performance. • Introduced Radial Plastic Flow Machining (RPFM) as a severe plastic deformation process. • Achieved one-step fabrication of gradient-structured copper terminals via RPFM. • Balanced high and low strain zones through varying extrusion angles. • Demonstrated significant improvement in hardness and tensile strength of copper terminals. • Confirmed good thermal stability at 150 °C for RPFM-prepared terminals. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) can be widely used to repair damaged plates in marine engineering equipment. To predict the fatigue life improvement by this repair, the stress intensity factor (SIF) of the cracked plate without/with repair is analyzed rigorously. Specifically, the SIF of a cracked plate without repair is analyzed and the error due to the finite element model (FEM) mesh is evaluated by comparing with the exact solution. By applying the same mesh having the same error, the exact SIF of the repaired plate is obtained in a convenient form. Fatigue experiments reveal that the same crack propagation parameters (C and m) can be applied for the unrepaired/repaired plates. Based on those, the prediction equation of fatigue life is obtained for cracked steel plates repaired with prestressed CFRP. The results show that this prediction method has the advantages of simplicity and efficiency. • The stress intensity factor (SIF) of an unrepaired/repaired cracked plate is investigated, and the convenient form of the exact SIF of the repaired plate is obtained by using the "proportional method". • It is found that crack expansion rates of unrepaired/repaired plates can be expressed by almost the same equations. • The correctness of prediction equation for prestressed-CFRP-repaired cracked steel plates is verified by fatigue test. • The enhancement effect of prestress on the fatigue life of cracked steel plate is quantitatively investigated. [ABSTRACT FROM AUTHOR]

The commitment and differentiation of human placental progenitor cytotrophoblast (CT) cells are crucial for a successful pregnancy, but the underlying mechanism remains poorly understood. Here, we identified the transcription factor (TF), specificity protein 6 (SP6), as a human species-specific trophoblast lineage TF expressed in human placental CT cells. Using pluripotent stem cells as a model, we demonstrated that SP6 controls CT generation and the establishment of trophoblast stem cells (TSCs) and identified msh homeobox 2 (MSX2) as the downstream effector in these events. Mechanistically, we showed that SP6 interacts with histone acetyltransferase P300 to alter the landscape of H3K27ac at targeted regulatory elements, thereby favoring transcriptional activation and facilitating CT cell fate decisions and TSC maintenance. Our results established SP6 as a regulator of the human trophoblast lineage and implied its role in placental development and the pathogenies of placental diseases. [Display omitted] • SP6 is a human species-specific trophoblast lineage transcription factor • SP6 interacts with trophoblast core transcription factors and epigenetic modifiers • SP6 determines cytotrophoblast generation and TSC establishment via MSX2 • SP6 interacts with P300 to alter the H3K27ac landscape at MSX2 loci Chen et al. demonstrated that SP6 is a trophoblast lineage TF specific to human species. It plays a role in controlling cytotrophoblast cell fate decisions and trophoblast stem cell maintenance by modifying the histone status at target sites, positioning this TF within the network of human placenta development. [ABSTRACT FROM AUTHOR]

Extrusion machining (EM) is an efficient and convenient method to prepare ultrafine-grained (UFG) materials. As a vital parameter in the EM process, tool rake angle (α) is critical to control the material's shear strain and grain size. The grains tend to refine with decreasing α , whereas a small α leads to difficult cutting, chip breakage, and poor surface quality. To achieve the controllable strain distribution, grain size adjustment, and improved formability of UFG pure copper strips, this paper proposed a novel design of the variable rake angle (VRA) tool. Combining experiments and finite element simulation, extrusion machining with variable rake angle tools (VRA-EM) was investigated. The results implied that a deviating angle (β) for the material flow existed during VRA-EM. The β increased as the cutting thickness (t c) increased, resulting in decreased plastic deformation, strain, and microhardness. The microstructure was also characterized by electron backscatter diffraction system (EBSD) and transmission electron microscopy (TEM) techniques. A dead metal zone was formed using the VRA tool, in which the material flow behavior was quite weak. The obtained UFG strip was further divided into the low-strain zone (LSZ) and high-strain zone (HSZ) based on strain distribution. And a new theoretical model of shear strain was established and conformed to experimental values. Accordingly, VRA-EM process was able to improve the mechanical properties and strain controllability, showing promising prospects for efficiently fabricating UFG materials. • A novel design of the variable rake angle (VRA) tool was proposed. • VRA-EM could achieve controllable strain distribution and grain size adjustment of UFG pure copper strips. • A deviating angle and a dead metal zone were formed during the VRA-EM. • The shear strain theoretical model of VRA-EM was established. [ABSTRACT FROM AUTHOR]

[Display omitted] • A colorimetric fluorescent probe was designed and synthesized for the detection of bisulfite with high sensitivity and selectivity in 100% aqueous solution. • The probe has been successfully used for the detection of SO 2 in food and animal serum samples with good recovery. • The probe was used as a solid sensor to visually detect the liquid and gas sulfur dioxide on the test strips. • The probe could detect both bisulfite in food and gaseous SO 2 in the environment. Bisulfite (HSO 3 −) has the functions of bleaching, antiseptic, antioxidant, inhibiting bacterial growth, and controlling enzymatic reactions in food. However, long-term consumption of foods containing excessive amounts of bisulfite can be harmful to health. In addition, large doses of sulfur dioxide (SO 2) can cause diarrhea, hypotension, allergic and asthmatic reactions in susceptible individuals. Therefore, it is urgent and essential to explore some rapid, reliable, and convenient tools to detect HSO 3 − in food and SO 2 gas. Herein, we exploited a fluorescent probe, NPO , to detect HSO 3 − in 100 % aqueous solution. The probe has the advantages of easy synthesis, excellent water solubility, significant colorimetric change, good selectivity, high sensitivity, and fast response (within 1 min). Probe NPO was successfully applied for testing strips to visualize the behavior of HSO 3 − and SO 2 gas. Moreover, the probe has been used to monitor the behavior of HSO 3 − in real food samples and animal serum samples. [ABSTRACT FROM AUTHOR]