Fabrication and research of 3D complex scaffolds for bone tissue engineering based on extrusion–deposition technique

Fabrication of scaffold is the key for bone tissue engineering, which is commonly regarded as the most potential route for repairing bone defects. Previously, porous ceramic scaffolds were fabricated through a variety of traditional methods, like moulding and casting, but most of them cannot produce customised tissue-engineered scaffolds. Therefore, 3D printing methods are gaining more attention and are currently being explored and developed to make scaffolds with acceptable biocompatibility. With the considerable development of bone tissue engineering, the bioactivity of scaffolds is becoming increasingly demanded, which leads to new methods and techniques to produce highly biomimetic bone scaffolds. In this study, a new fabrication process to optimise the structures of scaffolds was developed, and intensive researches were performed on the porous scaffolds to confirm their advantages in biological performance. Specifically, by combination of motor assisted extrusion deposition and gas-foaming (graphite as the porogen) technique, hierarchically porous scaffolds with improved microstructures, i.e. multi-scaled pores from nanometre to millimetre (nm-μm-mm), was successfully developed. In this thesis, the optimal content of porogen for scaffolds was studied in terms of compressive strength and in-rod porosities. The most concerned physicochemical properties of scaffolds were carefully examined and the results revealed that such scaffolds exhibit excellent physicochemical properties owing to hierarchically porous structures. Due to additional in-rod micropores and increased specific surface area, along with better hydrophilicity, hierarchically porous scaffolds exerted complete superiority in biological activity, including promoting cellular proliferation of osteoblasts, adhesion and spreading status, as well as the ability to induce cellular differentiation

Microstructural and mechanical analysis on Cu-Sn intermetallic micro-joints under isothermal condition

This study focuses on the mechanism of phase transformation from Cu6Sn5 into Cu3Sn and the homogenization process in full intermetallics (IMCs) micro-joints, which were prepared by soldering the initial Cu/Sn/Cu structure through high temperature storage in vacuum environment as the Transient Liquid Phase (TLP) process. From the microstructural observation by electron backscatter diffraction (EBSD), a mixture of IMCs phases (Cu6Sn5 and Cu3Sn) has been found to constitute the sandwich-structured Cu/IMCs/Cu joints. With the dwell time increasing at 533 K, there were two layers of Cu3Sn emerging from both sides of copper substrates with the depletion of Cu6Sn5 layer, toward merging each other in the IMCs interlayer. Then the Cu3Sn grains with various sizes became more homogenous columnar crystallites. Meanwhile, some equiaxial ultra-fine grains accompanied with the Kirkendall voids, were found only in adjacent to the electroplated copper. In addition, a specific type of micropillar with the size ∼5 μm × 5 μm × 12 μm fabricated by focus ion beam (FIB) was used to carry out the mechanical testing by Nano-indentation, which confirmed that this type of joint is mechanically robust, regardless of its porous Cu3Sn IMC interconnection

RRs and 95% CIs for (A) 2-year relapse risk and (B) 5-year OS, according to a subgroup analysis of CBF-AML.

<p>The number of included studies, number of patients in the included studies, and percentage of patients with <i>KIT</i> mutations in the included studies are listed.</p

Industrial Application of an Improved Multiple Injection and Multiple Staging Combustion Technology in a 600 MW_e Supercritical Down-Fired Boiler

To solve the water wall overheating in lower furnace, and further reduce NO_<i>x</i> emissions and carbon in fly ash, continuous improvement of the previously proposed multiple injection and multiple staging combustion (MIMSC) technology lies on three aspects: (1) along the furnace arch breadth, changing the previously centralized 12 burner groups into a more uniform pattern with 24 burners; (2) increasing the mass ratio of pulverized coal in fuel-rich flow to that in fuel-lean flow from 6:4 to 9:1; (3) reducing the arch-air momentum by 23% and increasing the tertiary-air momentum by 24%. Industrial-size measurements (i.e., adjusting overfire air (OFA) damper opening of 20–70%) uncovered that, compared with the prior MIMSC technology, the ignition distance of fuel-rich coal/air flow shortened by around 1 m. The gas temperature in the lower furnace was symmetric and higher, the flame kernel moved upward and therefore made the temperature in near-wall region of furnace hopper decrease by about 400 °C, the water wall overheating disappeared completely. Under the optimal OFA damper opening (i.e, 55%), NO_<i>x</i> emissions and carbon in fly ash attained levels of 589 mg/m³ at 6% O₂ and 6.18%, respectively, achieving NO_<i>x</i> and carbon in fly ash significant reduction by 33% and 37%, respectively

Number of death due to industrial accidents in China.

<p>Data from: National Economy and Society Developed Statistical Bulletin 2010–2015 from National Bureau of Statistics of the People’s Republic of China.</p

The final assessment result of risk score for each district.

<p>The final assessment result of risk score for each district.</p

The result of each part of the hierarchy.

<p>The result of each part of the hierarchy.</p

Membership function of the qualitative grades used to transform the quantitative data.

<p>Membership function of the qualitative grades used to transform the quantitative data.</p

The flow chart of the framework for assessment of RIS (Source: Authors).

<p>The flow chart of the framework for assessment of RIS (Source: Authors).</p

High Risk Inference (<i>HRI</i>).

<p>High Risk Inference (<i>HRI</i>).</p