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The “short pass” problem of liquid-liquid two-phase mixing at high phase ratios limited the development and applications of jet mixer in industrial process. In this study, the effect of the axial inlet angle on the mixing characteristics of a swirl jet mixer was investigated through laser particle size analysis and computational fluid mechanics (CFD) coupled with population balance model (PBM). The result was shown that as the axial inlet angle increased, the dispersed phase droplet sizes decreased, and the droplet size distribution was widened for the fixed mixer configuration. At Re≤ 3.000×104, tangential inlet was more conducive to improving mixing uniformity. Conversely, the axial inlet angle of 90° was optimal at Re≥ 3.750×104. Numerical simulations revealed that the tangential inlet effectively intensified liquid-liquid interactions, including streamlines extension, increased vorticity, improved droplet size uniformity. Additionally, the increase of the axial inlet angle resulted in increased turbulence stress and shortened decay period, the reduction in droplet size, and a wide droplet size distribution. The research findings can serve as theoretical basis for the hydraulic design and promoted applications of swirl jet mixers.

Due to the limited self-repair ability of the annulus fibrosus (AF), current tissue engineering strategies tend to use structurally biomimetic scaffolds for AF defect repair. However, the poor integration between implanted scaffolds and tissue severely affects their therapeutic effects. To solve this issue, we prepared a multifunctional scaffold containing loaded lysyl oxidase (LOX) plasmid DNA exosomes and manganese dioxide nanoparticles (MnO2NPs). LOX facilitates extracellular matrix (ECM) cross-linking, while MnO2NPs inhibit excessive reactive oxygen species (ROS)-induced ECM degradation at the injury site, enhancing the crosslinking effect of LOX. Our results revealed that this multifunctional scaffold significantly facilitated the integration between the scaffold and AF tissue. Cells were able to migrate into the scaffold, indicating that the scaffold was not encapsulated as a foreign body by fibrous tissue. The functional scaffold was closely integrated with the tissue, effectively enhancing the mechanical properties, and preventing vascular invasion, which emphasized the importance of scaffold-tissue integration in AF repair.

With the rising prominence of smart contracts, security attacks targeting them have increased, posing severe threats to their security and intellectual property rights. Existing simplistic datasets hinder effective vulnerability detection, raising security concerns. To address these challenges, we propose BiAn, a source code level smart contract obfuscation method that generates complex vulnerability test datasets. BiAn protects contracts by obfuscating data flows, control flows, and code layouts, increasing complexity and making it harder for attackers to discover vulnerabilities. Our experiments with buggy contracts showed an average complexity enhancement of approximately 174% after obfuscation. Decompilers Vandal and Gigahorse had total failure rate increments of 38.8% and 40.5% respectively. Obfuscated contracts also decreased vulnerability detection rates in more than 50% of cases for ten widely-used static analysis detection tools.

The dynamic extracellular matrix (ECM) constantly affects the behaviors of cells. To mimic the dynamics of ECM with controllable stiffness and energy dissipation, this study proposes a strategy in which a small molecule, 3,4-dihydroxybenzaldehyde (DB), was used as fast “dynamic bridges'’ to construct viscoelastic gelatin methacryloyl (GelMA)-based hydrogels. The storage modulus and loss modulus of hydrogels were independently adjusted by the covalent crosslinking density and by the number of dynamic bonds. The hydrogels exhibited self-healing property, injectability, excellent adhesion and mechanical properties. Moreover, the in vitroresults revealed that the viscous dissipation of hydrogels favored the spreading, proliferation, osteogenesis and chondrogenesis of bone marrow mesenchymal stem cells (BMSCs), but suppressed their adipogenesis. RNA-sequencing and immunofluorescence suggested that the viscous dissipation of hydrogels activated Yes-associated protein (YAP) by stabilizing integrin β1, and further promoted nuclear translocation of smad2/3 and β-catenin to enhance chondrogenesis and osteogenesis. As a result, the viscoelastic GelMA hydrogels with highest loss modulus showed best effect in cartilage and subchondral bone repair. Taken together, findings from this study reveal an effective strategy to fabricate viscoelastic hydrogels for modulating the interactions between cells and dynamic ECM to promote tissue regeneration.

The excessive reactive oxygen species (ROS) level, inflammation, and weak tissue regeneration ability after annulus fibrosus (AF) injury constitute an unfavorable microenvironment for AF repair. AF integrity is crucial for preventing disc herniation after discectomy; however, there is no effective way to repair the AF. Herein, a composite hydrogel integrating properties of antioxidant, anti-inflammation, and recruitment of AF cells is developed through adding mesoporous silica nanoparticles modified by ceria and transforming growth factor β3 (TGF-β3) to the hydrogels. The nanoparticle loaded gelatin methacrylate/hyaluronic acid methacrylate composite hydrogels eliminate ROS and induce anti-inflammatory M2 type macrophage polarization. The released TGF-β3 not only plays a role in recruiting AF cells but is also responsible for promoting extracellular matrix secretion. The composite hydrogels can be solidified in situin the defect area to effectively repair AF in rats. The strategies targeting endogenous ROS removal and improving the regenerative microenvironment by the nanoparticle-loaded composite hydrogels have potential applications in AF repair and intervertebral disc herniation prevention.

Annulus fibrosus (AF) repair remains a challenge because of its limited self-healing ability. Endogenous repair strategies combining scaffolds and growth factors show great promise in AF repair. Although the unique and beneficial characteristics of decellularized extracellular matrix (ECM) in tissue repair have been demonstrated, the poor mechanical property of ECM hydrogels largely hinders their applications in tissue regeneration. In the present study, we combined polyethylene glycol diacrylate (PEGDA) and decellularized annulus fibrosus matrix (DAFM) to develop an injectable, photocurable hydrogel for AF repair. We found that the addition of PEGDA markedly improved the mechanical strength of DAFM hydrogels while maintaining their porous structure. Transforming growth factor-β1 (TGF-β1) was further incorporated into PEGDA/DAFM hydrogels, and it could be continuously released from the hydrogel. The in vitroexperiments showed that TGF-β1 facilitated the migration of AF cells. Furthermore, PEGDA/DAFM/TGF-β1 hydrogels supported the adhesion, proliferation, and increased ECM production of AF cells. In vivorepair performance of the hydrogels was assessed using a rat AF defect model. The results showed that the implantation of PEGDA/DAFM/TGF-β1 hydrogels effectively sealed the AF defect, prevented nucleus pulposus atrophy, retained disc height, and partially restored the biomechanical properties of disc. In addition, the implanted hydrogel was infiltrated by cells resembling AF cells and well integrated with adjacent AF tissue. In summary, findings from this study indicate that TGF-β1-supplemented DAFM hydrogels hold promise for AF repair.

The regeneration mechanism of sulfated Cu/SAPO-34 catalysts in reducing atmospheres (5% H2/Ar and NH3/Ar at 600 °C) was investigated by using a series of characterization methods. Hydrogen regeneration improved the catalysts’ NH3-SCR activity from 150 to 550 °C remarkably, while ammonia regeneration exhibited relatively less obvious promotion effect. The TPR of hydrogen and EPR spectra data show that the regeneration process affects the amount and the coordination of the active isolated Cu2+species significantly. The desulfation increases the amount of isolated copper ions and improves the catalytic activity of SCR.

To investigate the effects of silica modification on the hydrothermal stability of the V2O5/WO3–TiO2catalyst, the catalysts were hydrothermally treated at 650 °C and 750 °C in 10 vol% H2O/air for 24 h. The fresh and aged catalysts were characterized by nitrogen physisorption (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (Raman), temperature-programmed reduction of H2(H2-TPR) and temperature-programmed desorption of NH3(NH3-TPD). Based on the experimental results, it is assumed that Si4+ions enter the TiO2lattice to form SixTi1−xO2solid solutions, which could inhibit the agglomeration of titania crystallites and anatase-to-rutile phase transition. These advantages of Si doping can essentially benefit the hydrothermal stability of V2O5/WO3–TiO2catalysts. The decrease of the SCR performance upon ageing is due to the extensive loss of surface area and evolution of vanadia species. Our observations show that the doped catalysts are stable at temperatures below 650 °C and the inactive VxTi1−xO2phase and crystalline V2O5form on the catalysts upon hydrothermal ageing at 750 °C.

Intervertebral disc degeneration (IVDD) is one of the main causes of low back pain. Although local delivery strategies using biomaterial carriers have shown potential for IVDD treatment, it remains challenging for intervention against multiple adverse contributors by a single delivery platform. In the present work, we propose a new functionalization strategy using vanillin, a natural molecule with anti-inflammatory and antioxidant properties, to develop multifunctional gelatin methacrylate (GelMA) microspheres for local delivery of transforming growth factor β3 (TGFβ3) toward IVDD treatment. In vitro, functionalized microspheres not only improved the release kinetics of TGFβ3 but also effectively inhibited inflammatory responses and promoted the secretion of extracellular matrix (ECM) in lipopolysaccharide-induced nucleus pulposus (NP) cells. In vivo, functionalized platform plays roles in alleviating inflammation and oxidative stress, preserving the water content of NP and disc height, and maintaining intact structure and biomechanical functions, thereby promoting the regeneration of IVD. High-throughput sequencing suggests that inhibition of the phosphatidylinositol 3-kinase (PI3K)-Akt signaling might be associated with their therapeutic effects. In summary, the vanillin-based functionalization strategy provides a novel and simple way for packaging multiple functions into a single delivery platform and holds promise for tissue regeneration beyond the IVD.

There is an urgent clinical need for the treatment of annulus fibrosus (AF) impairment caused by intervertebral disc (IVD) degeneration or surgical injury. Although repairing injured AF through tissue engineering is promising, the approach is limited by the complicated angle‐ply microstructure, inflammatory microenvironment, poor self‐repairing ability of AF cells and deficient matrix production. In this study, electrospinning technology is used to construct aligned core–shell nanofibrous scaffolds loaded with transforming growth factor‐β3 (TGFβ3) and ibuprofen (IBU), respectively. The results confirm that the rapid IBU release improves the inflammatory microenvironment, while sustained TGFβ3 release enhances nascent extracellular matrix (ECM) formation. Biomaterials for clinical applications must repair local AF defects during herniectomy and enable AF regeneration during disc replacement, so a box defect model and total IVD replacement model in rat tail are constructed. The dual‐drug delivering electrospun scaffolds are assembled into angle‐ply structure to form a highly biomimetic AF that is implanted into the box defect or used to replace the disc. In two animal models, it is found that biomimetic scaffolds with good anti‐inflammatory ability enhance ECM formation and maintain the mechanical properties of IVD. Findings from this study demonstrate that the multifunctional nanofibrous scaffolds provide inspirations for IVD repair. A novel aligned core–shell nanofibrous scaffold with angle‐ply microstructure and co‐delivery capacity is developed and its ability to repair and regenerate annulus fibrosus (AF) is tested. Burst release of ibuprofen can regulate the inflammatory microenvironment, and sustained release of transforming growth factor‐β3 can promote the secretion of extracellular matrix. It can not only repair the damaged AF, but also realize regeneration of intervertebral discs.

Biomimetic Structures Annulus fibrosus (AF) repair is critical for treating disc herniation. In article 2200895, Fengxuan Han, Bin Li, and co‐workers fabricate aligned core–shell nanofibrous scaffolds mimicking AF microstructure and realize temporal release of drugs for AF repair. Fast release of ibuprofen‐ameliorated inflammation and sustained release of TGFβ3 promote cell proliferation and ECM secretion.