To figure out the optimal strategy to manage Tetralogy of Fallot (TOF) with unbalanced pulmonary artery(PA) branches by investigating the different effects of PA plasty on the development of the ...hypoplastic PA (HPA).
A single center, retrospective analysis was carried out to compare the outcome of different PA plasty methods on the development of HPA in patients of TOF with unbalanced PA branches. Size and balance of the PA branches were used to evaluate the outcome of PA plasty.
In the NATIVE group, 100% of the HPAs were well-developed and all the PA branches became balanced, while in the PATCH and EXTENSION groups, the percentage of well-developed HPAs was 40% and 33%, respectively, and none of the PA branches were balanced. In addition, HPAs became atretic in 28% of the patients in the patch enlargement group.
For TOF with unbalanced PA branches, patch enlargement may not be a good treatment strategy, as it reduces the growth potential of HPA and even causes iatrogenic atresia. Leaving the HPA in the native state without patch enlargement may be a good strategy.
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•A record-high Wrec of 9.04 J cm−3 in BT-based relaxors with a large η of 87.2% are realized.•Coexisting multiphase ergodic polar nanoregions is successfully designed by phase ...boundary adjustment.•Excellent comprehensive performance of energy storage and mechanical is realized.•Structural correlation between energy storage and mechanical is established.
BaTiO3-based lead-free ceramics are mainstays of electrical functional materials in industry with mature technology and relatively low cost. However, the huge challenge of low recoverable energy storage density (Wrec) has long restricted their development in solid-state energy storage capacitors. Here, an ultrahigh Wrec of ∼9.04 J cm−3 and a large efficiency (η) of ∼87.2% are realized in BaTiO3-based relaxor ceramics via designing heterostructure formed by coexisting rhombohedral-tetragonal multiphase ergodic polar nanoregions. Encouragingly, outstanding mechanical properties (Vickers hardness ∼9.7 Gpa, compressive strength ∼500 MPa) are also achieved and the structural correlation between the energy storage and mechanical properties has been established, which are linked to the synergistic mechanisms of solid solution strengthening, denseness strengthening, grain boundary strengthening, and twin boundary strengthening. It is particular significance that this work provides an effective strategy to design new high-performance dielectric materials, accelerating the development of BaTiO3-based lead-free capacitors used in advanced energy-storage devices.
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Long-segmental tracheal defects constitute an intractable clinical problem, due to the lack of satisfactory tracheal substitutes for surgical reconstruction. Tissue engineered ...artificial substitutes could represent a promising approach to tackle this challenge. In our current study, tissue-engineered trachea, based on a 3D-printed poly (l-lactic acid) (PLLA) scaffold with similar morphology to the native trachea of rabbits, was used for segmental tracheal reconstruction. The 3D-printed scaffolds were seeded with chondrocytes obtained from autologous auricula, dynamically pre-cultured in vitro for 2 weeks, and pre-vascularized in vivo for another 2 weeks to generate an integrated segmental trachea organoid unit. Then, segmental tracheal defects in rabbits were restored by transplanting the engineered tracheal substitute with pedicled muscular flaps. We found that the combination of in vitro pre-culture and in vivo pre-vascularization successfully generated a segmental tracheal substitute with bionic structure and mechanical properties similar to the native trachea of rabbits. Moreover, the stable blood supply provided by the pedicled muscular flaps facilitated the survival of chondrocytes and accelerated epithelialization, thereby improving the survival rate. The segmental trachea substitute engineered by a 3D-printed scaffold, in vitro pre-culture, and in vivo pre-vascularization enhanced survival in an early stage post-operation, presenting a promising approach for surgical reconstruction of long segmental tracheal defects.
We found that the combination of in vitro pre-culture and in vivo pre-vascularization successfully generated a segmental tracheal substitute with bionic structure and mechanical properties similar to the native trachea of rabbits. Moreover, the stable blood supply provided by the pedicled muscular flaps facilitated the survival of chondrocytes and accelerated epithelialization, thereby improving the survival rate of the rabbits. The segmental trachea substitute engineered by a 3D-printed scaffold, in vitro pre-culture, and in vivo pre-vascularization enhanced survival in an early stage post-operation, presenting a promising approach for surgical reconstruction of long segmental tracheal defects.
For the development of lead-free Bi0.5Na0.5TiO3 prototype materials, it seems conflicting to improve the piezoelectric response (d33) and depolarization temperature (Td) simultaneously. Here, we ...propose a general chemical substitution method to simultaneously improve d33 and Td of Bi0.5Na0.5TiO3-BaTiO3 (BNT-BT) via introducing oxygen-defect perovskite. This has been demonstrated by introducing BaAlO2.5 into BNT-BT perovskite crystal lattice and forming solid-solutions, in which a series of ceramics with P4mm phase after electrical poling can be achieved. Not only its d33 but also Td can be much improved, which goes far beyond the performance boundary limit of d33 vs. Td for all BNT-BT based systems. The large d33 stems from the enhancement of lattice strain and domain switching confirmed by in situ synchrotron X-ray diffraction analysis. Critically, the improved Td originates from the increased tetragonality that caused by oxygen vacancies, as elucidated by the comparative experiments and density functional theory calculations. The present study provides a general method to tune the piezoelectric performance of BNT-based ceramics, and expects to benefit other piezoelectric materials.
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Objectives
To develop a rapid and simple method to fabricate intact, robust cell sheets from common cell culture dishes by combination of a macromolecular crowding (MMC) reagent and vitamin C.
...Results
It was found that 3T3 fibroblasts or human bone marrow mesenchymal stem cells (hBMSCs) and their secreted cell derived extracellular matrices could be easily detached as intact cell sheets under gently pipetting after treated by MMC and vitamin C for 4 days. This method also allowed fabrication of functional multi-layered hepatic cell sheets by culturing 10 × 10
4
cells/cm
2
HepG2 cells on top of confluent 3T3 fibroblast layers. What’s more, MMC induced hBMSC cell sheets demonstrated 1.9 times larger area and 1.6 times greater cell number than that of cell sheets harvested from temperature-responsive cell culture dishes.
Conclusion
MMC based method make it possible to fabricate various types of cell sheets more conveniently, economically, and thus may facilitate wide application of cell sheet technology.
Calcium bismuth niobate (CaBi2Nb2O9, CBN)-based ceramics are promising candidates for high temperature application, the electrical properties of which are commonly enhanced by complex ion ...substitution or texture processes. Here, we report that high piezoelectricity and high resistivity were achieved in Ca1-xBi2+xNb2O9 by constructing pseudo-tetragonal boundary through a simple strategy of Bi3+ self-doping. At the pseudo-tetragonal boundary, Ca0.96Bi2.04Nb2O9 ceramics maintain high Curie temperature Tc = 942 °C, and show high piezoelectric coefficient d33 = 15.1 pC/N and high resistivity ρdc = 2 × 106 Ω cm (@600 °C). It is proved that the good piezoelectric property mainly originates from the increase of domain density. In addition, Ca0.96Bi2.04Nb2O9 ceramics reveal good thermal depoling performance, remaining 90% of piezoelectricity after thermal depoling at 900 ℃, which is due to small thermal expansion and structural distortion. Our work provides a promising candidate for high temperature applications and an easy way to improve the performance of Aurivillius-type piezoelectric ceramics.
High-temperature piezoceramics are highly desirable for numerous technological applications ranging from the aerospace industry to the nuclear power sector. However, it is a grand challenge to ...achieve excellent piezoelectricity and high Curie temperature (T c) simultaneously because there is a contradiction between the large piezoelectric coefficient and high Curie temperature in piezoceramics. Here, we provide a perspective via B-site ion-pair engineering to design piezoceramics with high performance for high-temperature applications. In bismuth-layered Bi4Ti2.93(Zn1/3Nb2/3)0.07O12 ceramics, high piezoelectricity of d 33 = 30.5 pC/N (more than four times higher than that of pure Bi4Ti3O12 (d 33 = 7.3 pC/N) ceramics) in conjunction with excellent thermal stability, high Curie temperature T c = 657 °C, and large dc resistivity of ρ = 1.24 × 107 Ω·cm at 500 °C (three orders of magnitude larger than that of the pure Bi4Ti3O12 ceramics) are achieved by B-site Nb5+-Zn2+-Nb5+ ion-pair engineering. Excellent piezoelectricity is ascribed to sufficient orientation of the fine lamellar ferroelectric domain with the introduction of Nb5+-Zn2+-Nb5+ ion-pairs. The good temperature stability of d 33 originates from the stability of the crystal structure and the robustness of the oriented ferroelectric domain. The significantly improved resistivity is due to the restricted mobility of oxygen vacancies. This work presents a brand-new technique for achieving high-temperature piezoceramics with high performance by B-site ion-pair engineering.
Abstract In recent years, coaxial dual-rotor aircraft has attracted much attention due to its unique aerodynamic layout. However, it is difficult to miniaturize the coaxial dual-rotor aircraft that ...relies on the principle of periodic pitch variation due to complex structure and control difficulties. This study proposes a small cylindrical coaxial dual-rotor aircraft based on a vector motor seat. For the control problems of such coaxial dual-rotor aircraft, a position and attitude controller based on neural networks and adaptive cascaded PID control is designed. A control system model was established and tested using MATLAB/Simulink. The proposed control scheme’s soundness and efficiency were confirmed by creating a prototype and performing flight trials. The results show that compared with the classic PID controller, the control effect of the controller has improved by 36.3% to 54.6%. In the centripetal rotation flight simulation experiment, the displacement error does not exceed 0.2 m, the speed error does not exceed 0.05 m/s, and the attitude angle error does not exceed 0.01 rad. This validates the effectiveness of the designed controller, indicating that the controller can enhance the stability of the system and achieve stable hovering and flight.
Hydrogel multilayers with micrometer-scale in thickness containing living cancer cells were prepared by layer-by-layer assembling with 2-methacryloyloxyethyl phosphorylcholine polymer solution and ...poly(vinyl alcohol) solution alternatively under biological conditions. It was demonstrated that this tool could be utilized for minimizing barriers to the diffusion of drugs while preserving the 3D context. The contribution of dimensional and diffusional factors on drug efficacy was also investigated. As a case study, the cytotoxicity effects of paclitaxel on human cervical cancer HeLa-Fucci cells were evaluated in vitro. A comparative study was carried out: 2D culture, 3D culture in microgel thin membrane and in macrogel. Time-lapse microscopic analyses showed HeLa-Fucci cells cultured on 2D exhibited a more rapid and robust response to stimulation than cells cultured in microgel thin membrane. Besides, HeLa-Fucci cells cultured under macrogel did not show any response to stimulation. It was speculated that both of the diffusion of paclitaxel and matrix dimensionality could affect drug efficacy and diffusion of drug seemed to play a more important role. This study provides a versatile and experimentally convenient method to fabricate a useful and generalizable platform for cancer drug screening.
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