Mechanically-Guided Deterministic Assembly of 3D Mesostructures Assisted by Residual Stresses.

Formation of 3D mesostructures in advanced functional materials is of growing interest due to the widespread envisioned applications of devices that exploit 3D architectures. Mechanically guided assembly based on compressive buckling of 2D precursors represents a promising method, with applicability to a diverse set of geometries and materials, including inorganic semiconductors, metals, polymers, and their heterogeneous combinations. This paper introduces ideas that extend the levels of control and the range of 3D layouts that are achievable in this manner. Here, thin, patterned layers with well-defined residual stresses influence the process of 2D to 3D geometric transformation. Systematic studies through combined analytical modeling, numerical simulations, and experimental observations demonstrate the effectiveness of the proposed strategy through ≈20 example cases with a broad range of complex 3D topologies. The results elucidate the ability of these stressed layers to alter the energy landscape associated with the transformation process and, specifically, the energy barriers that separate different stable modes in the final 3D configurations. A demonstration in a mechanically tunable microbalance illustrates the utility of these ideas in a simple structure designed for mass measurement.

Fabrication and oil adsorption of carbon nanotube/polyvinylpyrrolidone surface composite.

It needs to assemble the industrial CNT powders into macroscopic porous surface composite to utilize the surface properties of CNTs, as well as to prevent them entering into environments. We demonstrate a method to fabricate the surface composites from CNTs and polyvinylpyrrolidone (PVP) by electrospinning, where CNTs distribute firmly and mainly on the surface PVP nanofibers. The CNTs/PVP surface composites have high pore volume of 10 cc/g and remarkable CNTs load of 98%. Thus the surface composites show high oil adsorption capacity of 0.9~1.1 g/cm3. It can absorb more oil than commercial sponges due to the surface composite swells after absorbing oil. It shows attractive potential application of the CNT/PVP surface composite in oil spill cleanup.

Preparation of highly elastic superhydrophobic CNF/Fe3O4 based materials modified in aqueous phase for oil-water separation.

Magnetic superhydrophobic materials have broad application prospect in oil-water separation. In this study, a magnetic and superhydrophobic aerogel with lamellar structure was successfully prepared using cellulose nanofibrils (CNF) as the skeleton, Fe3O4 as the magnetic ion, 1H, 1H, 2H, 2H trialkylfluorooctane triethoxysilane (FS) and 3-(2-aminoethyl amino)-propyl trimethoxysilane (AS) as the combined modifier. The prepared aerogel shows lower density (38.63 mg/cm3), excellent magnetic (15.13 emu/g), high elasticity and good oil sorption properties (21 g/g). In addition, FS/AS also exhibits excellent mechanical properties and superhydrophobic ability (water contact angle (WCA) of 151.9 ± 1.4°), as it provides sufficient toughness and low surface energy for the layer-branch structure. It should be noted that the entire preparation process is carried out in the aqueous phase, without the use of any organic solvents, providing a green oil-water separation strategy.

Risk Factors for Hidden Blood Loss Associated with Vertebroplasty or Kyphoplasty for Osteoporotic Vertebral Compression Fracture: A Systematic Review and Meta-Analysis.

OBJECTIVE: Hidden blood loss (HBL), as a perioperative complication of percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP), affects the quality of life of older adults with poor health status, but it is often ignored by clinical surgeons. The purpose of this study was to discuss the risk factors for perioperative HBL through meta-analysis. METHODS: We systematically searched PubMed, Embase, Cochrane Library, Web of Science, Scopus, Google Scholar, Chinese National Knowledge Infrastructure, and Wan Fang from establishment of the database to September 2022. All eligible studies regarding risk factors for HBL after PVP or PKP were included. Heterogeneity was assessed using the χ2 test and I2 statistic percentages. If I2 >50% or P < 0.1, the random-effect model was used; otherwise, the fixed-effect model was used. Data were analyzed with Revman 5.4 and Stata 16.0. RESULTS: Eleven studies involving 1506 patients were included and the average HBL of PKP and PVP was 278.57 mL and 276.12mL. The results showed that bone cement leakage (P < 0.0001), thoracic vertebra (P < 0.00001), bilateral surgical approach (P = 0.0008), ≥2 fracture segments (P < 0.00001), vertebral body height loss rate (≥1/3) (P < 0.00001), and vertebral body height restoration rate (≥1/3) (P < 0.00001) were risk factors for increased HBL. Diabetes (P = 0.12) and hypertension (P = 0.52) were not significantly associated with HBL. CONCLUSIONS: The findings of this meta-analysis suggested that fracture level, surgical approach, number of fracture levels, cement leakage, vertebral height loss and restoration rate were significant risk factors for HBL, which had certain guiding significance for clinical surgeons to take reasonable measures to deal with this complication.

Fatigue test of helical nervous electrodes and weak point analysis of helical nervous electrodes design.

Due to the increasing number of both implantation and removal of the helical nervous electrodes, the safety and the reliability of the electrode becomes an important issue in its clinical application-particularly its fatigue failure caused by body movement. Utilizing fatigue testing, we evaluated the weak points of the helical electrode. Our data analysis for fatigue cycles recorded by the fatigue test equipment showed that the adhesive strength between the silicone and suture, and the load of the electrode were essential for the mechanical durability of the electrode. The locations of the weak points and improvements for helical electrode design were given. The suggestions of decreasing damages to the nerves in clinical use will be helpful to the surgeons.