The present work investigates, in situ, the in vitro bioactivity of partially crystallized 45S5 Bioglass (BG) as a function of immersion time in a simulated body fluid (SBF) using atomic force microscopy (AFM). The results obtained for the crystallized BG were compared to those of hydroxyapatite c- and a-faces. The calcium phosphate layer grows on the crystallized 45S5 B by multiple two-dimensional nucleation and fusion of these two-dimensional islands, which is essentially the same mode as for the hydroxyapatite c-face. The surface of the crystallized 45S5 BG was almost fully covered with a dense and compact calcium phosphate layer after 24 h. The calcium phosphate formation on the crystallized BG arises from a low surface energy of the surface layer and/or an effect of the layer to lower the resistance when the growth units of calcium phosphate incorporate into the growing island. These results indicate that the crystallized 45S5 BG is suitable to be used as a filler for polymeric matrix bioactive composites, as it maintains a high bioactivity associated with a stiffer behavior (as compared to standard BG).

The present research aims to evaluate the possibility of creating new degradable, stiff and highly bioactive composites based on a biodegradable thermoplastic starch-based polymeric blend and a Bioglass filler. Such combination should allow for the development of bioactive and degradable composites with a great potential for a range of temporary applications. A blend of starch with ethylene-vinyl alcohol copolymer (SEVA-C) was reinforced with a 45S5 Bioglass powder presenting a granulometric distribution between 38 and 53 microm. Composites with 10 and 40 wt % of 45S5 Bioglass were compounded by twin-screw extrusion (TSE) and subsequently injection molded under optimized conditions. The mechanical properties of the composites were evaluated by tensile testing, and their bioactivity assessed by immersion in a simulated body fluid (SBF) for different periods of time. The biodegradability of these composites was also monitored after several immersion periods in an isotonic saline solution. The tensile tests results obtained indicated that SEVA-C/Bioglass composites present a slightly higher stiffness and strength (a modulus of 3.8 GPa and UTS of 38.6 MPa) than previously developed SEVA-C/Hydroxylapatite (HA) composites. The bioactivity of SEVA-C composites becomes relevant for 45S5 amounts of only 10 wt %. This was observed by scanning electron microscopy (SEM) and confirmed for immersion periods up to 30 days by both thin-film X-ray diffraction (TF-XRD) (where HA typical peaks are clearly observed) and induced coupled plasma emission (ICP) spectroscopy used to follow the elemental composition of the SBF as function of time. Additionally, it was observed that the composites are biodegradable being the results correlated with the correspondent materials composition.

The rates of (1) devolatilisation, (2) char combustion and (3) char gasification with CO 2 of plywood sawdust (Australian Standard 2207 'Interior Grade') was measured using non-isothermal thermogravimetric analysis (TGA). The influence of heating rate (β = 5, 10, 20, 50 and 100• C/min) and reaction atmosphere (N 2 , Air, CO 2 ) was investigated. Irrespective of the reaction atmosphere, devolatilisation typically occurred at the same rate. Weight loss attributed to char oxidation was observed at temperatures >400• C, while weight loss due to CO 2 gasification of char was observed at temperatures >800• C. There was uncertainty about the fate of some of the constituents of the plywood sawdust, i.e. urea-formaldehyde binders, which could not be fully evaluated using a TGA system without evolved-gas analysis. These components appeared to volatilise around 380• C on the differential mass loss profiles in the presence of N 2 and CO 2 and around 490• C in the presence of air. A simple first-order reaction model was used to interpret the experimental observations. The kinetic parameters for the main components of plywood sawdust were consistent with those reported previously for other biomass materials. This information is potentially useful for the design of large-scale equipment to recover energy from discarded wood wastes. 

Objective. To investigate the effect and safety of 3D printing technology in proximal femoral osteotomy in children with developmental dysplasia of the hip. Methods. 40 cases of children with developmental dysplasia of the hip treated by pelvic osteotomy combined with proximal femoral osteotomy at Ningbo No. 6 Hospital from January 2017 to December 2019 were retrieved and retrospectively analyzed. Among them, 20 cases received preoperative measurement and design assisted by 3D printing technology (the 3D printing group), and 20 cases received conventional preoperative measurement and design (the conventional group). Results. All patients were followed up for an average of 25 (12~36) months. During the follow-up, there were no complications such as infection, fracture of internal fixation, or malunion of osteotomy. Compared with the conventional group, the 3D printing group had a shorter operation time, less intraoperative blood loss, and fewer intraoperative X-ray fluoroscopies (all p < 0.05 ). In the last follow-up, the clinical efficacy was evaluated by the McKay standard: in the 3D printing group, 14 cases were excellent, 5 cases were good, and 1 case was fair. In the conventional group, 10 cases were excellent, 9 cases were good, and 1 case was fair ( Z = − 0.382 , p > 0.05 ). Conclusion. Preoperative 3D printing of bilateral femur and other large physical models is accurate, which is ideal for the development of individual preoperative planning. Proximal femoral osteotomy using preoperative measurements and simulated surgical data improves the safety of the operation.

In this paper, the cross-linked micro-gel polymer between acrylamide (AM) and N, N-Methylenebisacrylamide (MBA) was synthesized by dispersion polymerization. The initiator and crosslinking agent concentration were used to control the particle size of micro-gel polymer. The filtration property and mechanism of micro-gel were investigated comprehensively. The characteristics of micro-gel were checked by means of Fourier transform infrared spectroscopy, thermogravimetry, transmission electron microscopy, and particle size distribution, respectively. The results indicated that the cross-linked micro-gel polymer exhibited several outstanding merits, such as thermal stability (up to 200 °C), filtration control and rheological property. Microstructure analysis and particle size distribution examinations showed that the scale of micro-gel polymer was micro, which is in accord with design. Rheological tests demonstrated that the nonlinear structure of micro-gel polymer showed less impact on the apparent viscosity. The anti-high temperature property of micro-gel polymer was better than poly anioniccellulose (PAC) and asphalt widely applied in drilling fluid for anti-high temperature fluid-loss additive. As a result, the cross-linked micro-gel polymer had great potential to be applied in high temperature water-based mud.