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Coal fly ash (CFA) as a potential resource for rare earth elements and yttrium (REY) has attracted extensive attention over the past few years. This paper focuses on studying microwave systems for the leaching of REY from CFA. Leaching parameters including hydrochloric acid (HCl) concentration, microwave heating time, microwave heating rate, and temperature were assessed. The optimal recovery of 74.91% REY, 86.77% light rare earth elements (LREY), and 34.79% heavy rare earth elements (HREY) are obtained at the conditions of 3 M HCl, T = 220°C, heating rate 39°C/min, and leaching time 30 min. The closed microwave system produces hydrogen chloride fluid or hydrogen chloride gas that is easier to react with CFA than hydrogen ions. It was revealed by the analysis of XRD, particle size, porosity, and SEM that fracture development benefits the entrance of leaching reagents into the inner layer of CFA. A positive linear correlation was found between leaching efficiency and REY3+ ionic radius. The stability of the REY-O bond also remains consistent with the ionic radius, leading to behavior differences during the leaching. This work was targeted to provide a theoretical and technological foundation for microwave-assisted HCl leaching for the extraction of REY in CFA. [ABSTRACT FROM AUTHOR]

Bioleaching exhibits high potential for the processing of low-grade complex mineral resources. With the development of the economy and an increase in demand, rare earth elements (REEs) in secondary resources, such as phosphogypsum, red mud and coal-related resources, are gaining more and more attention. In this review, the bioleaching performance of diverse microorganisms is summarized and compared for primary (mainly monazite) and secondary REE resources, based on publications from the past decade. The mineral characteristics of these REE resources are different, as they can be found in phosphate, sulfate, or silicate forms. Correspondingly, microbial species suitable for use in bioleaching differ. The most efficient bioleaching microbe for monazite is Paecilomyces sp., while Acidianus manzaensis is effective in processing red mud. Acidophilic sulfur oxidizers are suitable for processing acidic phosphogypsum. Acidithiobacillus thiooxidans could recover a significant amount of REEs from coal fly ash. In particular, monazite has a high REE content but extremely low bioleaching efficiency compared to that of secondary resources, supporting the understanding that bioleaching approaches are more competitive for minerals with low REE contents. Overall, great progress has been made over the last decade, as considerable REE recovery rates have been achieved, and the main metabolites of microbes were identified. However, numerous challenges still exist. Future efforts should focus on improving biorecovery efficiency, reducing the cost of cell-culture media, and exploring the interaction mechanism between cells and minerals, with an emphasis on mineralogical phase transformations and the molecular regulation mechanisms inside cells during the bioleaching process. [ABSTRACT FROM AUTHOR]

The occurrence and separation relationships of Na and maceral groups in Zhundong coals were investigated in this study. The sequential extraction results indicate that the total Na content of all samples decreased with increasing sampling depth, and the level in inertinite-enriched samples (inertinite content 81.0%–84.0%) was significantly higher than that in corresponding raw coals and vitrinite-enriched samples (vitrinite content 90%). Additionally, H2O-Na (soluble salt species) and insoluble Na (acid-insoluble residues) were found to be concentrated in the inertinite-enriched samples. In combined SEM–EDS and microscope observations, local Na enrichments were detected in all raw coal and inertinite-enriched samples except for the vitrinite-enriched samples, but only inertinite-enriched samples were found to generally have over 10 wt% of Na enrichments, all of which occurred as NaCl. Moreover, Na is mostly filled or associated with cell-filling minerals in cells of fusinite. The maceral separation and Na removal of Zhundong coal were simultaneously achieved using triboelectrostatic separation. The vitrinite content in concentrates increased up to 60%, along with a reduced Na level, while the inertinite and sodium levels were both evidently raised in tailings. The obvious positive occurrence and separation correlation between sodium and inertinite offers new insight into, and a technical reference for, the sodium removal and maceral processing of Zhundong coal. [ABSTRACT FROM AUTHOR]

The Ti6Al4V alloy is one of the most commonly used in orthopedic surgery. Mechanical property of implant contributes important biological functions for load-bearing bone tissue reconstruction. There is a significant need for design and fabrication of porous scaffold with customized mechanical properties for bone tissue engineering. In this paper, bionic design and fabrication of porous implants were studied by using finite element analysis (FEA) and 3D printing techniques. Novel porous architectures were built up with diamond lattice pore structure arraying units. With finite element analysis, the structure weak points under pressure were simulated so that the mechanical properties of the implants were optimized. Porous implants with different porosities and mechanical properties were precisely fabricated by selected laser melting (SLM), one of powder bed fusion additive manufacturing techniques. The biocompatibility and repair effect were studied by in vivo experiments. Animal results indicated that the damaged load-bearing bones were well reconstructed. New generated bones embedded and fitted into the designed porous implants. The optimized design and precisely manufactured implants are conducive to bone tissue repair and reconstruction. [ABSTRACT FROM AUTHOR]

The active sites of mineral surfaces play an important role in many industrial processes, such as mineral flotation and dewatering. This paper was aimed to investigate the effect of Al- and Si-active sites on the mineral crystal faces exposed to water on the electrokinetic properties, surfactant adsorption, and floatability of diaspore and kaolinite, which are, respectively, the valuable and gangue minerals in the processing of diasporic bauxite ores. Specifically, the acid treatment was used to change the physicochemical properties of diaspore and kaolinite minerals for their selective flotation. Microelectrophoresis method was used to determine the zeta (surface) potential of diaspore and kaolinite particles before and after the acid treatment as a function of pH. The change in the surface potential was analyzed applying the theory on the electrical double layers at the solid-solution interface. The proton donor–acceptor reactions occurring simultaneously on amphoteric alumina or/and silica sites of diaspore and kaolinite were considered. The mass balances were applied to link the surface active sites with the minerals charge and potential. Comparing the modeling with the experimental data revealed the significant decrease in the Al-active sites and increase in the Si-active sites by the acid treatment. Single mineral flotation and surfactant adsorption tests of diaspore and kaolinite before and after the acid treatment were carried out using sodium hexametaphosphate (HMP) and dodecylamine hydrochloride (DAH) as a depressant and a collector, respectively. After the acid treatment, the adsorption density of depressant on both diaspore and kaolinite decreased due to the reduced density of Al-active sites on the minerals surfaces. The changes of collector adsorption capacity and floatability of diaspore were very small while those of kaolinite were significantly increased. These changes were caused by decreasing the density of Al-active sites (covered by HMP and thereby preventing DAH adsorption) on both diaspore and kaolinite and increasing the density of Si-active sites of kaolinite (not covered by HMP and thereby facilitating DAH adsorption). The results clearly indicated that the acid treatment was shown to be conducive to changing the active Al- and Si-sites on diaspore and kaolinite and thereby improving their flotation separation. [ABSTRACT FROM AUTHOR]

Diasporic bauxite represents one of the major aluminum resources. Its upgrading for further processing involves a separation of diaspore (the valuable mineral) from aluminosilicates (the gangue minerals) such as kaolinite, illite, and pyrophyllite. Flotation is one of the most effective ways to realize the upgrading. Since flotation is a physicochemical process based on the difference in the surface hydrophobicity of different components, determining the adsorption characteristics of various flotation surfactants on the mineral surfaces is critical. The surfactant adsorption properties of the minerals, in turn, are controlled by the surface chemistry of the minerals, while the latter is related to the mineral crystal structures. In this paper, we first discuss the crystal structures of the four key minerals of diaspore, kaolinite, illite, and pyrophyllite as well as the broken bonds on their exposed surfaces after grinding. Next, we summarize the surface chemistry properties such as surface wettability and surface electrical properties of the four minerals, and the differences in these properties are explained from the perspective of mineral crystal structures. Then we review the adsorption mechanism and adsorption characteristics of surfactants such as collectors (cationic, anionic, and mixed surfactants), depressants (inorganic and organic), dispersants, and flocculants on these mineral surfaces. The separation of diaspore and aluminosilicates by direct flotation and reverse flotation are reviewed, and the collecting properties of different types of collectors are compared. Furthermore, the abnormal behavior of the cationic flotation of kaolinite is also explained in this section. This review provides a strong theoretical support for the optimization of the upgrading of diaspore bauxite ore by flotation and the early industrialization of the reverse flotation process. [ABSTRACT FROM AUTHOR]

Rapid monitoring of cleaned coal quality with soft sensors is essential for efficient production and control of the jigged fluidized bed. In this study, a new explainable modeling method for refined coal quality prediction in coal-jigged fluidization is proposed. The models were developed based on the 47 process variables of air pressure, buoy height, belt weight, water flow, gate opening, bucket level, hydraulic, and feed frequency. By comparing the performance of the two ensemble learning models, the results show that XGBoost predicts lower MAE (1.16%) and RMSE (1.72%) for cleaned coal quality. In addition, the SHapley Additive explanation (SHAP) is employed to interpret the contributions and analyze the importance of each process variable. The SHAP results indicate that nine important variables (Maximum buoy height of the 3- and 4-bed area, amplitude of gate opening of the 3- and 4-bed area, Gangue belt weight, Gangue bucket level, hydraulic of the 3- and 4-bed area and Feed frequency) contributed the most to ash content prediction of cleaned coal, which Gini coefficient higher than 0.2. Then, the XGBoost predictor is optimized again based on the 9 variables selected based on SHAP contributions. The results show that the MAE and RMSE of the XGBoost model are reduced by 0.24% and 0.40%, respectively. In contrast, the method in this paper effectively addresses the prediction of cleaned coal quality in the jigged fluidized bed, where the contribution of variables obtained by SHAP can be used as a theoretical basis for developing optimal control for jigged fluidized bed. [ABSTRACT FROM AUTHOR]

The occurrence characteristics of sodium and its potential relationship with macerals in Zhundong coal, as well as in Shenfu coal with average sodium levels, are investigated in this study. A new five-step sequential extraction method was first conducted for determination. The occurrence status of sodium and its related macerals in samples was determined by microscope and SEM–EDS (scanning electron microscope–energy dispersive X-ray spectroscopy). Soluble sodium salts (H2O-Na) make up the primary proportion of sodium in Zhundong coal, at approximately 50%, while various sodium species are distributed in Shenfu coal with nonobvious differences. Inertinite contains more sodium than vitrinite does in both coals, and the highest enrichment degree of sodium was discovered in inertinite from Zhundong coal, which presented primarily as NaCl crystals (H2O-Na) in fusinite cells, with a local weight percentage of over 15%. More specifically, H2O-Na and insoluble Na both tend to enrich in fusinite. Additionally, it is found that maceral-rich products can be gathered using triboelectrostatic separation, and a portion of sodium can thus be removed from the coal by removing inertinite. This study may provide new insights and references regarding sodium removal from Zhundong coal. [ABSTRACT FROM AUTHOR]

Coal ash (CA) is not only one of the most solid wastes from combustion, easily resulting in a series of concerns, but it is also an artificial deposit with considerable metals, such as iron and rare earth. The variation in the coal ash characteristics due to the origins, combustion process, and even storage environment has been hindering the metal utilization from coal ash. In this study, three ash sample from lab muffle, circulating fluidized bed (CFB), and pulverized coal (PC) furnace was derived for the discrepancy study from the combustion furnace, including properties, iron, and rare earth recovery. The origins of the coal feed samples have more of an effect on their properties than combustion furnaces. Magnetic separation is suitable for coal ash from PC because of the magnetite product, and the iron content is 58% in the Mag-1 fraction, with a yield of 3%. The particles in CA from CFB appear irregular and fragmental, while those from PC appear spherical with a smooth surface. The results of sequential chemical extraction and observation both indicated that the aluminosilicate phase plays an essential role in rare earth occurrences. Rare earth in CA from muffling and CFB is facilely leached, with a recovery of approximately 50%, which is higher than that from PC ash. This paper aims to offer a reference to easily understand the difference in metal recovery from coal ash. [ABSTRACT FROM AUTHOR]

• Bastnaesite and monazite were found in the coal gangue from Jungar Coalfield. • Calcination makes rare earth carriers into more soluble fractions. • 78.8% of REY and 88.5% of Al were extracted at optimal conditions. • REY leaching is controlled by interfacial transfer and diffusion through solid layer. • The higher extraction rate of LREY than HREY is affected by monazite in coal gangue. Critical metals in coal-based byproducts have been gradually regarded as one of the most important alternative resources due to the market parameters, strategic perspective, and advanced technology. In this study, the mechanism of calcination-acid leaching for rare earth elements (REY) recovery from coal gangue of Jungar coalfield was proposed based on the results of sample characteristics, extraction law, kinetic analysis, and typical mineral leaching. The micro-particles of bastnaesite and monazite were found and embedded in the kaolinite via micro-observation with SEM-EDS. Kaolinite in coal gangue calcined at 600 ℃ was transformed into highly positively reactive metakaolinite, enhancing the dissolution of aluminum (Al) and exposing the rare earth minerals encapsulated within the particles. Meanwhile, bastnaesite was thermally decomposed into rare earth oxides and rare earth fluorides. Rare earth oxides are more easily dissolved by acid, and the fluoride ions and the aluminum ions form a stable complex ion [AlF 6 ]3-, which promotes the dissolution of rare earth fluoride. In addition, a high REY and Al recovery (78.8% of REY, and 88.5% of Al) came true from calcined coal gangue at optimal conditions. The leaching kinetics showed that REY leaching followed the hybrid control model of interfacial transfer and diffusion through solid layer, while Al leaching is controlled by chemical reaction. The leaching test of monazite shows that the leaching efficiency of LREY is higher than that of HREY indicating the leaching difference of LREY (82.3%) and HREY (61.3%) in coal gangue is mainly influenced by monazite. This may be related to the crystal structure and the radius of trivalent rare earth ions. This study provides a useful reference for the extraction of REY from coal gangue. [ABSTRACT FROM AUTHOR]

[Display omitted] • H 2 TiO 3 (HTO) was modified by Cu doping to improve adsorption properties. • HTO-Cu-0.04 afforded cell expansion and increased hydrophilicity due to Cu doping. • HTO-Cu-0.04 had enhanced Li+ adsorption capacity than HTO (35.58 vs 22.41 mg·g−1). • The adsorption rate of HTO-Cu-0.04 was 12 times greater than that of HTO. H 2 TiO 3 (HTO) is one promising type of lithium-ion sieves (LISs) due to its theoretical adsorption capacity, stability and selectivity, but its actual adsorption ability is restricted. Since the larger radius of Cu ions than that of Ti4+, Cu doping was performed in this work for the purpose to improve adsorption performance by enlarging Li+ transport channels. The doping content of Cu as well its effect on structures, properties and adsorption performance of LISs were examined by various techniques. After trace doping of Cu, the hydrophilicity and specific surface area of HTO-Cu-0.04 (0.04 is the doping content) were improved, which can increase adsorption sites and accelerate Li+ diffusion process. And thus, HTO-Cu-0.04 owned enhanced adsorption capacity than HTO (35.58 vs 22.41 mg·g−1 at 298 K) and some other metal doped HTO in literature despite different adsorption conditions. The Li+ adsorption on HTO-Cu-0.04 is spontaneous and endothermic, following Langmuir isotherm model and pseudo-second-order kinetics model. The adsorption selectivity was examined in the simulated brine of Li+, Na+, K+, Ca2+, and Mg2+, which was analyzed by the distribution coefficient (K d,Li) and separation factor (α M Li). After five adsorption–desorption cycles, the adsorption capacity of HTO-Cu-0.04 amounts to 95.8 % of the initial value, showing high stability. This work provides guidance for doping engineering to increase Li+ diffusion channels and hydrophilicity of LISs for improved Li+ recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • A heterogeneous structure was built via a Voronoi-Thiessen based parametric modeling method. • Heterogeneity had little influence on porosity, thus, mechanical/hydrodynamic properties. • Irregular local geometry mimicked cancellous bone structure and promoted cellular behavior. • 50% heterogeneity (SR structure) kept a balance of structure integrity and osteogenesis. In nature, many natural porous tissues of animals or plants follow heterogeneous structures pattern. Including turtle back pattern, leaf veins, wood porous fiber and porous cancellous bone are classic heterogeneous structures. In order to better design bionic microenvironment porous bone implants, herein, a bionic porous structure based on Voronoi-Thiessen diagram to create heterogeneous topology microenvironment promoting bone regeneration were proposed. Porous structures with tunable heterogeneity were built and achieved by selective laser melting (SLM). The topology analysis revealed the introduce of heterogeneity brought wide pore size distribution and irregular topology. The mechanical and hydrodynamics properties were predesigned and simulated by finite element analysis (FEA). The heterogeneity hardly influenced the overall strength, stiffness and permeability but the irregular stress and fluid shear rate distribution in FEA results indicated fluctuating local stiffness and permeability. In vitro and in vivo experimental results indicated that Quasi-homogeneous structure had irregular topology mimicking that of the natural bone structure and semi-heterogenous structure shown better osteogenesis. It is found that the scaffold heterogeneous microenvironment factors play important roles for bone regeneration, and which is crucial for the development of new orthopedic implants. [ABSTRACT FROM AUTHOR]

Critical metallic elements in coal gangue have great utilization potential, especially due to the current shortage of these metals. This paper focused on examining the feasibility of physical separation (screening and float-sink tests) and calcination treatment for the enrichment of critical elements (Li, Ga, and rare earth elements plus yttrium (REY)) from coal gangue. The impacts of these enrichment methods on the acid leaching recovery of these elements were then studied. Screening tests indicated that Li and Ga were enriched in >0.125 mm size fraction and the content of REY was highest in <75 μm size fraction. Float-sink tests showed that high-density fractions were enriched in Li and Ga, and low-density fractions were enriched in REY. Physical separation cannot significantly improve the leaching rate of Li, Ga, and REY. Notably, Li, Ga, and REY were enriched significantly, and their acid leaching recoveries were increased by 54~68% after calcination under 400 °C. Sequential chemical extraction tests showed that the majority of insoluble Li, Ga, and REY was converted into soluble forms at the above temperature, which is attributed to the formation of amorphous metakaolinite and the decomposition of organic matter. Based on the results, a conceptually combined flowsheet was proposed for the extraction of Li and Ga from coal gangue. [ABSTRACT FROM AUTHOR]

In current clinical applications, spinal fusion predominantly are mostly inertness biomaterials with dense structures, which restrict the interface for new bone growth and impede the formation of interlocking structures, thereby caused failed bone integration. To address these challenges, this research proposed a novel 3D printed nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composited biological scaffold. Fused Deposition Modeling (FDM) technology was used to fabricate optimized porous architecture scaffold with balanced mechanical properties. A coating of polydopamine nanoparticles (nPDA) loaded with Parathyroid Hormone (PTH) (1–34) was then prepared on the scaffold surface, it effectively mitigated the inflammatory response and enhancing bone integration. In vitro results indicated a sustained release of PTH (1–34) would promote the osteogenic ability of scaffold. In vivo results demonstrated that the composited biological scaffold exhibited good ability to induce bone tissue regeneration which is beneficial for spinal fusion applications. [ABSTRACT FROM AUTHOR]

Human understanding of skin is constantly ongoing. Great progress has been made in skin repair, wound dressing regeneration biomaterials research in recent years. This review introduced the clinical research and guiding principles of skin repair, wound dressing biomaterials at home and abroad, introduced the classification of various skin repair and wound dressing, listed the composition and performance of different dressing biomaterials, including traditional, natural, synthetic, tissue-engineered dressing materials were extensively reviewed. The biological molecular structures and biological function characteristics of different dressing biomaterials are comprehensively reviewed. Collagen, chitosan, alginate hydrogels et al. as the most popular biological macromolecules in skin repair and wound dressing applications were reviewed. The future development direction is also prospected. This paper reviews the research progress of advanced functional skin repair and wound dressing, which provides a reference for the modifications and applications of wound dressings. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D printing was used to fabricate Nanohydroxyapatite/Polyamide 66 bone tissue scaffold. • The scaffold shows balanced mechanical property and osteogenic ability. • Scaffold promoted endogenous bone regeneration in rabbit patellar bone defects. The biomaterial requirements for bone tissue repair are extremely strict. It not only requires the biomaterial to have good biocompatibility and biological activity, but also requires sufficient mechanical strength. Polyamide 66 (PA66) and nano-hydroxyapatite (n-HA) have been widely investigated in bone tissue engineering scaffold, however, its composites require further research. In this study, the 3D printing technology was utilized to fabricate personalized n-HA/PA66 bone tissue scaffold. The mechanical properties of n-HA/PA66 composite can be adjusted by configuring different raw material components and applying different porosity. It was found that 50 % porosity n-HA/PA66 composite scaffold showed a uniform porous structure and a compressive strength of 33.9 MPa. The composite scaffold also exhibited excellent biological properties while improving mechanical properties, in vitro cell tests indicated that the 3D printed n-HA/PA66 composite scaffold promoted differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts. In in vivo animal model proved that the scaffold promoted endogenous bone regeneration in rabbit patellar bone defects, with newly formed bone volume of 20.9 % after two months of implantation. This research proposed a 3D printed polyamide/nano-hydroxyapatite composite with balanced mechanical property and osteogenic ability for customized bone tissue repair, and it has promising application prospects. [ABSTRACT FROM AUTHOR]

[Display omitted] • Critical-sized trabecular bone region defects are challenging in orthopedics. • Magnesium composite material fabrication and personalized bone repair scaffolds. • Mg/n-HA/PLA induces osteogenesis and angiogenesis. • It has potential for clinical development and application. Critical-size trabecular bone defects remain challenging to treat in orthopedic clinical practice. This study utilized a polyethylene glycol dispersion method to uniformly disperse magnesium (Mg) and nano-hydroxyapatite (n-HA) in a polylactic acid (PLA) solution, resulting in the fabrication of an Mg/n-HA/PLA composite material. We next generated personalized bone repair scaffolds through Fused Deposition Modeling (FDM) 3D printing. The composite scaffolds were characterized, and their biocompatibility, osteogenic properties, and angiogenic capabilities were assessed through in vitro experiments. In vivo experiments were conducted to explore the pathways underlying osteogenesis and angiogenesis. The results confirmed that the properties and biological efficacy of the Mg composite material could be regulated by controlling the quantitative ratio of Mg. The results showed that the 10 % Mg composite group exhibited optimal osteogenic properties, whereas the 20 % Mg composite group showed the best angiogenic effects and the most promising induction properties. The beneficial effect of the composite scaffold was associated with the interconnected REK and FAK/HIF-1/VEGF signaling pathways. In conclusion, the Mg composite biomaterial exhibited desirable processability, mechanical properties, and degradability, and induced osteogenesis and angiogenesis. These features of composite scaffold meet the complex requirements for treating critical-size trabecular bone defects in load-bearing animals and having potential for clinical development and application. [ABSTRACT FROM AUTHOR]

Jaw bone repair requires scaffold with bone regeneration, antibacterial function and personalized size. This study proposed 3D printed degradable calcium phosphate scaffolds with antibacterial functions for regeneration of jaw bone. Calcium phosphate powders and berberine were combined to modulate the printing inks. Porous scaffolds were fabricated by direct extrusion 3D printing and cross-linked with sodium alginate in situ. The dimensional size, shape and porosity of scaffolds were precisely customized by 3D printing. Berberine-loaded scaffolds show sustained release of antimicrobial drugs. By adjusting the concentration and cross-linking time of calcium chloride, the cross-linking degree of the scaffold can be adjusted and the drug load of the scaffold can be controlled. The young's modulus of 3DP scaffold was about 1.3 MPa. After freeze-drying, the shrinkage was about 24.4% and less swelling was observed, indicating that the scaffold had sufficient structural stability. In vitro biological test showed that the 3DP scaffold had low cytotoxicity and it was beneficial to MC3T3 cell adhesion and proliferation. 3D printed calcium phosphate scaffolds with controlled-release antibacterial properties is a promising biomaterials for jaw repair. Unlabelled Image • Calcium phosphate powders and berberine were combined to modulate the printing inks. • Porous scaffolds were fabricated by direct extrusion 3D printing. • Porous scaffolds were cross-linked with sodium alginate in situ. • The dimensional size, shape and porosity of scaffolds were precisely customized by 3D printing. • Berberine-loaded scaffolds show sustained release of antimicrobial drugs. [ABSTRACT FROM AUTHOR]

Background: To assess the impact of lymph node dissection (LND) extent on overall survival (OS) and cancer-specific survival (CSS) in patients with pN0M0 renal cell carcinoma (RCC) treated with radical nephrectomy (RN). Materials and methods: Data queried for this study include RCC (2010–2014) from the Surveillance, Epidemiology, and End Results (SEER) program. Kaplan–Meier analyses and multivariate Cox regression models tested the effect of number of removed lymph node (NRN) ≥ 50th percentile on OS and CSS. The associations were evaluated using propensity score (PS) matching adjustment. Results: A total of 5532 pN0M0 RCC patients were enrolled in our study. The median NRN was 2 (IQR 1–6), the 50th percentile defined patients with NRN ≥ 2. Following PS adjustment, there were no significant differences in clinicopathologic features between two groups of patients except for age. Multivariate model analysis showed that patients with NRN < 2 had worse OS than those with NRN ≥ 2 in pT3 group (HR 1.442; P = 0.032) but not in pT1 and pT2 groups (HR 0.859 and 1.393, P = 0.443 and P = 0.267, respectively). However, patients with NRN < 2 had better CCS than those with NRN ≥ 2 in pT1 group (HR 0.368; P = 0.016) but not in pT2 and pT3 groups (HR 1.674 and 1.325, P = 0.216 and P = 0.176, respectively). Conclusions: More extensive LND (NRN ≥ 2) at RN is associated with better OS in pT3N0M0 RCC patients while it exerts negative influence on CCS in pT1N0M0 group. Hence, more extensive LND has therapeutic value in pT3 individuals but not in pT1 group. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lithium occurs in the octahedron of the kaolinite lattice via charge compensation. • Thermal activation in nitrogen atmosphere is more favorable to lithium extraction. • 44.82 % of lithium was selectively leached out with almost undissolved aluminum. • Lithium in the octahedron moves outside by thermal activation, facilitating exchange. Lithium (Li), an important strategic metal, has been paid attention to by researchers, entrepreneurs, and political circles, especially its recovery from coal-based solid waste. In this paper, the occurrence modes of Li in coal gangue (CG) have been studied through sequential chemical extraction, distribution correlation, and intercalation-leaching test. The CG was pretreated via grinding-thermal activation to selectively leach Li. The correlation between Li and magnesium (Mg) during the leaching process was also investigated. Finally, the migration mechanism of Li during the grinding-thermal activation process was analyzed using solid-state nuclear magnetic resonance for the first time. The results of the first three experiments demonstrated that Li primarily exists within the kaolinite. The extraction of Li from CG after grinding-thermal activation is 44.82 % using 0.2 M (NH 4) 2 SO 4 (pH = 4.0), while aluminum (Al) was almost insoluble, exhibiting the selective leaching of Li. 84.76 % of Li and 17.63 % of Al are obtained at pH = 1.0. The correlation analysis result suggests that lithium ions (Li+) exist in the octahedron of the lattice as charge compensation. The migration mechanism is explained by the chemical shift of Li+, which moves from −0.196 ppm (raw, in the octahedron) to −0.319 ppm (ground, octahedral destruction) and further to −0.564 ppm (thermal activation, out of the octahedron). This paper can provide a theoretical basis for the occurrence of Li and a new method for selective extraction of Li from CG. [ABSTRACT FROM AUTHOR]

The regeneration of the osteochondral complex in situ presents a significant challenge. The inherent hypoxic microenvironment of cartilage plays a critical role in facilitating osteochondral repair. The successful regeneration of the osteochondral complex necessitates the utilization of materials and structures that closely mimic its composition. In this study, carboxymethyl chitosan (CCS), oxidized hyaluronic acid (OHA), and tannic acid (Ta) were employed to fabricate an injectable and self-healing hydrogel (Ta@gel). The incorporation of Ta within the hydrogel network enables preferential oxidation, thereby creating an anoxic microenvironment within the hydrogel. Bone marrow-derived mesenchymal stem cells (BMSCs) were encapsulated within microspheres composed of methacrylic anhydride gelatin (GelMA). These microspheres were subsequently loaded into a Ta@gel. The resulting bionic hydrogel composite was then combined with a three-dimensional (3D) printed hydroxyapatite (HAp) scaffold coated with poly- l -lysine (PLL). This combination resulted in the formation of a bionic three-layer composite structure (HAp@PLL + Ta@gel + GelMA@BMSCs) that closely resembles the complex composition and structure of natural osteochondral complex. The efficacy of this customized triphasic composite scaffold in promoting osteochondral complex regeneration has been demonstrated in vitro and in vivo. Consequently, this study provided a new sight for inducing the in situ regeneration of cartilage. [Display omitted] • A natural cartilage mimicking hydrogel is fabricated. • Hypoxic microenvironment promotes chondrogenic differentiation. • Three-dimensional printed hydroxyapatite scaffold is coated with poly-L-Lysine. • A composite mimicking the osteochondral complex is customized. [ABSTRACT FROM AUTHOR]

• Silane coupling agent was grafted onto H 2 TiO 3 to yield a new composite. • The agglomeration of the new composite is relieved after surface modification. • The new composite owned improved lithium adsorption capacity and adsorption rate constant. Solid-phase reaction is a promising method to synthesize lithium-ion sieves H 2 TiO 3 (HTO) for simple production process. However, the uneven mixing of raw materials during the solid-phase reaction causes the agglomeration phenomenon. In this work, silane coupling agent (3-aminopropyl)triethoxysilane (KH550) was employed for surface modification of HTO to yield the HTO/KH550 composite by forming covalent bond. The crystallinity, composition, morphology, and porosity of HTO/KH550 were characterized by a series of techniques. The agglomeration phenomenon was well alleviated and HTO/KH550 showed increased surface area. The adsorption experiments were detailed carried out by varying the different factors. HTO/KH550 exhibited improved lithium adsorption capacity and adsorption rate constant (25.61 mg·g−1 and 0.0037 mg·g−1·h−1 vs 22.41 mg·g−1 and 0.0020 mg·g−1·h−1 of HTO) derived from surface modification by KH550. Ion exchange mechanism in the adsorption process was revealed by X-ray photoelectron spectroscopy (XPS). Selective adsorption experiments were performed and HTO/KH550 exhibited the partition coefficient (K d) of Li+ much higher than the competing ions (Na+, Mg2+, K+, and Ca2+). Furthermore, HTO/KH550 showed excellent cyclic stability with the adsorption capacity loss of only 3.3 % after five adsorption–desorption cycles. This work is of guiding significance to synthesize surface modified lithium-ion sieves for industrial production. [ABSTRACT FROM AUTHOR]

A two-step method involving microwave-assisted hydrothermal synthesis and solid-phase calcination was employed to prepare the Li 1.6 Mn 1.6 O 4 (LMO) precursor. Material characterization demonstrated the structural stability of LMO even after acid pickling, resulting in the creation of the ion-sieve H 1.6 Mn 1.6 O 4 (HMO) with the most notable Li+ adsorption capacity of 29.45 mg·g−1. The adsorption isotherm of HMO adhered to the Langmuir isothermal model (R 2 = 0.9929), indicating a smooth and monolayer adsorption process. Simultaneously, the adsorption kinetics of HMO was consistent with the pseudo-second-order kinetic model (R 2 = 0.9911), indicative of chemisorption. Upon undergoing five adsorption-desorption cycles, HMO's adsorption capacity remained above 22.32 mg·g−1. Evaluation of the distribution coefficient (K d) and the separation factor (α Me Li) for HMO in both coal gangue leaching solution and simulated salt lake brine highlighted its exceptional selectivity. Notably, HMO achieved a remarkable 99.9% adsorption rate in the coal gangue leaching solution. These outcomes underscore the efficacy of the synthesized HMO in highly selective Li+ recovery from both coal gangue and salt lake brine, additionally emphasizing the potential of coal gangue as a valuable lithium resource with significant prospects for future development and utilization. [Display omitted] • The Li 1.6 Mn 1.6 O 4 was prepared by a microwave-assisted hydrothermal method. • The first application of lithium ion-sieve adsorption to realize the enrichment of lithium in coal gangue leaching solution. • The adsorption rate of H 1.6 Mn 1.6 O 4 in the coal gangue leaching solution reached 99.9%. [ABSTRACT FROM AUTHOR]

• A multiscale feature extraction method based on NSCT was developed. • An algorithm for enhancing froth image contrast using reconstruction was proposed. • Features were extracted from froth images with fuzzy binarization. • The multiscale features yielded markedly better results than the single scale. • Multiscale features improve the classification accuracy. Visual features at the froth surface of a flotation cell are closely related to the process condition and performance. Accurate identification of flotation conditions is crucial. However, the multi-scale properties of froth images are not all extracted based on existing perception methods. Considering that multi-scale frequency domain analysis can obtain more informative statistical froth features, a new working condition recognition based on nonsubsampled contourlet transform (NSCT) multiscale features is proposed and successfully validated by industrial froth images taken under different process conditions. NSCT was used to enhance the froth image, including the decomposition and reconstruction, contrast-limited adaptive histogram equalization (CLAHE), and multi-scale features of the enhanced image are extracted and analyzed. The fuzzy binarization method is adopted for extracting the morphological feature. Texture feature parameters are extracted from other high-frequency images. The particle swarm optimization support vector machine is used to recognize the working condition. The results indicate that the proposed algorithms, in particular the multiscale features classification based on NSCT, have the highest classification accuracy (93.33 %), and can accurately and reliably identify the working condition in the actual froth images. [ABSTRACT FROM AUTHOR]

• Heterogenous mechanics and structure of the spine system, including intervertebral bodies and discs, were visualized by finite element analysis. • Heterogeneous architected lattice structure was achieved by a parametrical modeling strategy. • The well-designed heterogeneous structure triggered the stress reorganization on intervertebral cage mimicking the natural stress distribution. • The heterogeneous design promote spinal fusion compared to conventional design. The common phenomenon of cage subsidence after intervertebral fusion may lead to intervertebral foramen stenosis and implantation failure. In this study, a heterogeneous porous cage was designed to trigger the stress reorganization so as to avoid intervertebral cage subsidence and promote spinal fusion. Firstly, finite element analysis (FEA) was used to predict the heterogenous stress distribution on intervertebral discs. Then, a heterogeneous porous structure cage was inspired by the stress reorganization method. Parametrical modeling was employed to customize the porous structure of the cage. Heterogenous Ti6Al4V cage was successfully fabricated via selective laser melting 3D printing. The results from FEA simulation indicated that heterogenous cage with a dense periphery and a porous center may drive the load outward which mimicking the natural stress distribution of spine system. Finally, an animal model between the C3-C4 vertebras of goats was studied to prove the effectiveness of the cage fusion. The histological and micro-CT results indicated that the heterogeneous structure may accelerate bone tissue ingrowth so as to promote osteointegration and fusion. Compared with conventional cage, the heterogenous cage may avoid subsidence and this heterogenous structure provide a promising strategy for customized bio-fusion intervertebral cage. [ABSTRACT FROM AUTHOR]

Enhanced osteogenesis and angiogenesis capacity of 3D printed porous PLGA/n-HA scaffolds incorporated with magnesium phosphate. [Display omitted] • Porous PLGA/n-HA/MgP composite (PHM) scaffolds are fabricated by FDM. • Doping of MgP accelerates the degradation of scaffolds and buffers the acid environment caused by PLGA degradation. • Scaffold with 10% MgP ratio shows good effect on osteogenesis and neovascularization. • Over 30% MgP content shows a negative effect on bone regeneration. The osteogenic and angiogenic characteristics are crucial for the selection of bone substitute materials and structural design. This study proposed a porous PLGA/n-HA/MgP composited scaffold by printing of the poly (lactide-coglycolide) (PLGA), nano-hydroxyapatite (n-HA), and magnesium phosphate (MgP). The physicochemical properties, osteogenic activities, and pro-angiogenic impacts of porous 3D printed PLGA/n-HA scaffolds with variable MgP concentration were investigated. The results indicated that the presence of MgP in the composite promoted scaffold degradation and buffered the acidic environment induced by PLGA degradation. The highest pro-osteogenic activity has been observed in PLGA/n-HA/10% MgP (PH10M) group, which up-regulated BMP2 and RUNX2 factors in vitro and in vivo. Nevertheless, at a maximal ion release of 7.2 mmol/L, PLGA/n-HA/30% MgP (PH30M) marginally reduced the osteogenic differentiation of osteoblasts through the RANKL/OPG pathway. In vitro, PLGA/n-HA/20% MgP (PH20M) demonstrated superior migration, pro-angiogenic factor expression, and angiogenesis compared to other groups, and the histological investigation corroborated the improved angiogenesis in PH10M and PH20M. In conclusion, suitable MgP ratio shows the potential to improve the osteogenic and angiogenic properties of PLGA/n-HA-based composites in orthopedic applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Abstract Hydroxyapatite coating was constructed by a modified hydrothermal approach, which employing chelated calcium to enhance the medium stability and increase the generated amount. • The 3D printed integrative hydroxyapatite/titanium intervertebral cages contribute to osteogenic differentiation of BMSCs according to qRT-PCR and Transcriptome results. • The integrative titanium/hydroxyapatite intervertebral cage design, compared with typical split cage/graft cage, showed better bone tissue ingrowth and spinal fusion ability. 3D printed porous titanium cage is believed with physiology mechanical properties and biocompatibility for orthopedic usage. Typical split cage design with a grafting window and infilled bone graft has raised a lot of questions. In this research, a modified hydrothermal approach, employing chelated calcium to enhance the medium stability and increase the generated amount, is proposed to construct bioactive hydroxyapatite coating inside the porous structure of 3D printed porous titanium cage. The in vitro and transcriptomic results indicated the hydroxyapatite enhanced the cells physical sensing system, therefore enhanced the osteogenesis inside titanium/hydroxyapatite cage. The in vivo goat spinal fusion experiment indicated the integrative titanium/hydroxyapatite cage, compared with typical split cage/graft cage, showed better bone tissue ingrowth and spinal fusion ability. This research provides a promising hydroxyapatite coating strategy for complex porous structure and revealed the potential advantage of integrative titanium/hydroxyapatite intervertebral cage design. [ABSTRACT FROM AUTHOR]

Titanium and its alloys have been widely used as bone tissue engineering scaffold due to their excellent biocompatibility and mechanical strength. In order to promote bone ingrowth, integration and match the mechanical properties of natural bone tissue, this study proposed diamond-like microstructure porous Ti-6Al-4V scaffolds for personalized bone defect repair. In order to prepare the multiple biological functional coatings on the curve surface inside of the 3D printed porous scaffolds, pulsed electrodeposition method was proposed to obtain multiple layers of Ti 3 C 2 T x /HAp composited coatings. Delaminated Ti 3 C 2 T x has an ultra-thin microstructure according to transmission electron microscopy (TEM) observation and is well dispersed in electrolyte. X-ray diffraction (XRD) characterization shows that Ti 3 C 2 T x has been synthesized and regulates more CaHPO 4 ‧2H 2 O (DCPD) to Hydroxyapatite (HAP) conversion, which is confirmed by Fourier transform infrared spectroscopy (FTIR) at 0.2 mg/mL concentration. Scanning electron microscopy (SEM) shows that the morphologies of composite coatings are closely related to Ti 3 C 2 T x content due to the availability of effective voltages for electrodeposition. By means of finite element method, deposition thickness and distribution of coatings were simulated to explore the precipitation kinetics and selection of electrodeposition parameters and a current density of 15 mA/cm2 was ultimately used. In vitro electrochemical corrosion of Ti 3 C 2 T x /HAp coatings were tested in human simulated body fluid (SBF) to verify its corrosion resistance in physiological environment and Ti 3 C 2 T x /HAp composited coatings possess the best corrosion resistance according to linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) tests. In vitro MC3T3-E1 cell culturing studies were investigated to evaluate cell behaviors and biocompatibility of these coatings. The results indicate that cells grow well on the surface of composite coatings without showing cytotoxicity and cell morphologies show a good spreading state and a trend of inward growth. • MXenes/HAp composite coatings have been prepared on the surface of 3D printed bone tissue engineering scaffolds by pulse electrodeposition. • Ti 3 C 2 T x -MXenes promotes the homogeneous nucleation of hydroxyapatite during electrodeposition process and possesses good biocompatibility and multiple biological functions. • The electrodeposition process was simulated by finite element analysis, and the deposition kinetics was studied to optimize the process parameters. • Customized parametric design of electrolytic cell and electrodeposition scaffolds for composite coating preparation process. [ABSTRACT FROM AUTHOR]

The repair of large bone defects is still a challenge in clinical orthopedics. The combination of composite materials and 3D printing is expected to produce ideal bone defect scaffolds. This research studied the combined polylactic acid (PLA), nano-hydroxyapatite (n-HA), and lithium (Li) bone tissue scaffold via 3D printing. The n-HA/PLA/Li composite scaffold was proposed by screening the optimal proportion, biocompatibility, and osteoinductive activity. The degradation and mechanical properties of the proposed specimens were evaluated. Osteogenesis and vasculogenesis were detected in vitro , and the regulatory pathways were explored to screen the doping amount of lithium ions. In vivo, the PLA/n-HA/Li composited scaffold was used for the beagle dog heterotopic and rabbit femur orthotopic osteogenesis studies. Results indicated that the mechanical strength of PLA/n-HA/Li composited scaffold decreased with the increase of the n-HA ratio. The 30% n-HA scaffold group showed a good comprehensive performance of printability and mechanical strength. Based on the osteoinductive activity, 0%, 0.5%, and 1% lithium-doped scaffolds were studied and screened. The 1% lithium group exhibited the best degradation, osteogenesis, and angiogenesis properties in vitro than other groups and could induce ectopic osteogenesis and in situ osteogenesis in vivo. This PLA/n-HA/Li composite biomaterial shows good printability, biocompatibility, degradability, and osteogenic inducibility, it has application potential in the personalized repair of large bone defects. [ABSTRACT FROM AUTHOR]

• The first interpretable machine learning model for the relationship between elements and ash content. • Al, S, Si, Fe, Ca, Ti, K, Sr and Zr has the greatest contribution to ash content prediction. • Complex interrelated indicators of element features are captured and analyzed. • RFR model produced a superior prediction performance over other models. • The authors declared that they have no conflicts of interest to this work. As one of the most important indexes of coal quality, accurate and rapid prediction of ash content is urgent and important significance for the coal processing industry. In this work, combined with Shapley Additive exPlanations (SHAP), a machine learning model has been developed to predict the ash content of coal samples based on composition data of XRF analysis. Among the many supervised regression learning algorithms, Poly, RFR, XGBoost, and DNN are used in this predictive model to overcome the ash content prediction research gap. The input parameters were the elements content and ash contents of the coal samples. To evaluate the proposed method, a dataset of XRF data was constructed, containing 217 sets of element content with different ash content labels. Specifically, the dataset is divided into a training set and test set in the proportion 8:2, and RandomizedSearchCV is used to optimize hyperparameters during model training. Experimental results show that the RFR model produced a superior prediction performance over other models (the RMSE, MAE and R2 were 1.3278, 0.9339 and 0.9916, respectively). The contribution and role of each element to the ash prediction model are explained and investigated. Moreover, as a result of SHAP interpretation, the nine most important elements (Al, S, Si, Fe, Ca, Ti, K, Sr and Zr) has the greatest contribution to model performance. The case of this paper suggests that interpreted machine learning models and XRF data are good alternatives to ash content prediction. [ABSTRACT FROM AUTHOR]

The hydrogel composited hydroxyapatite (HAp) scaffold shown biomimetic extracellular matrix and osteogenic activity, which is a promising bone regeneration biomaterial. 3D printing has been widely used in fabrication of customized and complex bone regeneration scaffold. However, it is still a challenge to prepare high-precision HAp reinforced composites by digital light processing (DLP) printing that can effectively promote bone regeneration. In this study, shear-thinning gelatin methacrylamide (GelMA)/hydroxyapatite (HAp) composite inks were prepared to fabricate high-precision scaffolds by DLP printing for bone repair. Firstly, GelMA hydrogels with adjustable mechanical, rheological and printing properties were synthesized to screen hydrogel concentration and degree of substitution. Then carefully selected biocompatible dispersants to reduce the agglomeration of hydroxyapatite. The actual printing resolution of the GelMA/HAp porous composite scaffolds with excellent mechanical strength through DLP 3D printing was up to about 100 μm. In vitro, the 3D printed composite scaffold significantly promoted the adhesion and proliferation of osteoblasts, as well as promoted osteogenic differentiation. In vivo, the GelMA/HAp porous composite scaffolds showed excellent ability in accelerating the formation of new bone in rabbit skull defects. The GelMA/HAp porous composite scaffolds fabricated by the composite inks with good printability, mechanical properties and osteogenic activity have fascinating potential in bone repair application. [ABSTRACT FROM AUTHOR]

Biomimetic mineralization has been widely applied in the preparation of bone repair materials for achieving better mechanical and biological properties. However, the mineralization effectiveness is not quite satisfactory. Herein, enhanced biomimetic mineralization was realized through polyphosphate modification of gelatin. Molecular dynamics simulations theoretically demonstrated the effectiveness of poly-phosphorylation in augmenting mineralization. Experimental results revealed that poly-phosphorylation could increase the saturation of in-situ mineralization of gelatin from about 25% to more than 40%. Consequently, the compressive strength and elastic modulus of the enhanced mineralized composite were increased by 57.93% and 132.55%, respectively. The osteogenesis was also promoted. Combined with 3D printing, the scaffolds not only had the advantages of enhanced in-situ mineralization but also were endowed with the macro-controllable porous structure to achieve better bone regeneration. It interpreted the mechanism of biomimetic mineralization in terms of the saturation of in-situ mineralization and provided a viable strategy for biomimetic scaffold preparation. Enhanced biomimetic mineralization is achieved through effective in-situ mineralization of polyphosphate modified gelatin. Experiments verify that poly-phosphorylation could increase the saturation of gelatin mineralization from about 25% to more than 40%, by providing more nucleation sites of hydroxyapatite. Combined with 3D printing, the scaffolds are endowed with controllable porous structure, which offers a new avenue to manufacture bone regenerative scaffolds biomimetically. [Display omitted] • Enhanced biomimetic mineralization of organic-inorganic composites was achieved by efficient mineralization of piGel. • It theoretically and experimentally demonstrated the effectiveness of poly-phosphorylation in augmenting mineralization. • The view of saturation of in-situ mineralization was first proposed to interpret the mechanism of enhanced mineralization. • The mechanical and biological properties of enhanced-mineralized nanocomposites were improved greatly. • 3D printing was applied to achieve the construction of the personalized scaffolds. [ABSTRACT FROM AUTHOR]

Coal fly ash (CFA) as a secondary resource has received a great deal of attention over the past few decades. Research on rare earth elements (REEs) and unburned carbon removal by flotation from CFA is burgeoning, respectively. It will be beneficial if REEs could be rich in the flotation product with the carbon removal. In this study, the optimization of flotation for the unburned carbon removal was investigated and near 100% removal came true with loss on ignition of 56% and the yield of 7.7%. The optimal conditions contain rotation speed of 600 rpm and time of 30 min using the collector of 1200 g/t, the frother of 140 g/t, and the density of 130 g/t for the flotation. The majority of REEs occurred in the tailing after the flotation due to the low yield and REEs contents of the concentrates. The difference of REEs distribution in the tailing and concentrate is more significant in the milled sample. The morphology was also observed to explain the microscale behavior of REEs during the flotation. [Display omitted] • Flotation-acid leaching combined process is proposed to recovery of unburned carbon and REEs in CFA. • Different operation parameters are studied in flotation-leaching system. • The main factors causing the floatability of CFA were found and discussed. • Grinding can effectively remove unburned carbon and enrich REEs in flotation tailings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcium phosphate scaffolds with accuracy porosity were fabricated by 3D printing. • Icariin served as a controlled release of osteogenic drug for bone regeneration. • Multi-level porosity regulates the drug release behavior. • 3D printed scaffolds show improved mechanical strength. The purpose of this research was to repair critical size defects of a skull. First, the CT data on the Beagle's skull were used to reconstruct an implant model. Then two Ф15 mm critical bone defects on the left and right sides of the skull were drilled. Hydroxyapatite, sodium alginate and icariin were adopted to formulate the printing inks according to their proportions. Calcium phosphate scaffolds with accuracy porosity were 3D printed by an extrusion printer. Icariin served as a controlled release of osteogenic drugs for bone regeneration. The physical and chemical properties of the 3D printed scaffolds were summarized, and in vitro and in vivo tests were conducted to assess the biocompatibility and the bone repair ability of the scaffolds. According to the mechanical results, the 3D printed calcium phosphate scaffolds show improved mechanical strength, and the Young's modulus was about 4.23 MPa, while the compressive strength was 9.37 MPa. The drug release test results showed that the slowly controlled release of osteogenic drugs behavior by the 3D printed calcium phosphate scaffolds continuously promoted new bone formation. The in vitro biological assessment results suggested that the 3D printed calcium phosphate scaffolds had good biocompatibility, with no obvious cytotoxicity observed. An animal model, aimed at achieving personalized accurate repair of the critical size defects on the skull, indicated that the 3D printed calcium phosphate scaffolds with controlled release of osteogenic drugs had great potential for regeneration of critical bone defects. [ABSTRACT FROM AUTHOR]

The current gold standard for auricular reconstruction after microtia or ear trauma is the autologous cartilage graft with an autologous skin flap overlay. Harvesting autologous cartilage requires an additional surgery that may result in donor area complications. In addition, autologous cartilage is limited and the auricular reconstruction requires complex sculpting, which requires excellent clinical skill and is very time consuming. This work explores the use of 3D printing technology to fabricate bioactive artificial auricular cartilage using chondrocyte-laden gelatin methacrylate (GelMA) and polylactic acid (PLA) for auricle reconstruction. In this study, chondrocytes were loaded within GelMA hydrogel and combined with the 3D-printed PLA scaffolds to biomimetic the biological mechanical properties and personalized shape. The printing accuracy personalized scaffolds, biomechanics and chondrocyte viability and biofunction of artificial auricle have been studied. It was found that chondrocytes were fixed in the PLA auricle scaffolds via GelMA hydrogels and exhibited good proliferative properties and cellular activity. In addition, new chondrocytes and chondrogenic matrix, as well as type II collagen were observed after 8 weeks of implantation. At the same time, the transplanted auricle complex kept full and delicate auricle shape. This study demonstrates the potential of using 3D printing technology to construct in vitro living auricle tissue. It shows a great prospect in the clinical application of auricle regeneration. • The anatomical structure of auricle was accurately fabricated by CT data and 3D printing. • 3D printed porous poly (lactic acid) scaffolds promote tissue ingrowth. • GelMA hydrogel maintains chondrocyte phenotype. • New cartilage was observed in 3D printing auricle in vivo. [ABSTRACT FROM AUTHOR]

Polylactic acid/Hydroxyapatite (PLA/HA) composite was widely studied and applied in the field of biomaterials for its good processability, bioactivity, and mechanical properties. In addition to traditional preparation methods, additive manufacturing has also been adopted to prepare PLA/HA composites with customized geometries. This work combined the comprehensive optimized PLLA (L-polylactic acid)/nano-HA (nHA) composite with the low-cost and stable Fused deposition modeling (FDM) technology to successfully prepare PLLA/nHA porous bone repair scaffolds. The results showed that PLLA/nHA composite ink satisfied the smoothness of printing, and the accuracy also met the requirements of personalized bone repair application. The high loaded nHA scaffold had suitable compressive strength was significantly higher than those of pure HA ceramic scaffold and cancellous bone. Besides, in vitro bone-like apatite formation on the surface in the degradation process and in vivo evaluations further verified its good osteogenic property. Compared with other complex and cutting-edge 3D printing technologies, this study provides a low-cost, stable, simple and fast way to realize personalized printing of bone repair scaffolds, which is undoubtedly conductive to the improvement and rapid deployment of personalized biomaterials in clinical applications. Unlabelled Image • Comprehensive optimized PLLA/nano-hydroxyapatite composite was made successfully for bone repair scaffold printing. • Bone-like apatite can form on the scaffold surface in vitro degradation experiments just in PBS, indicating the high bioactivity of scaffold. • The high loaded nano- hydroxyapatite scaffold has suitable compressive strength and good osteogenic property. • This study provides a low-cost, stable, simple and fast way to realize personalized printing of bone repair scaffolds. [ABSTRACT FROM AUTHOR]

Scaffold micro-topological structure plays an important role in the regulation of cell behavior in bone tissue engineering. This paper investigated the effect of 3D printing parameters on the scaffold micro-topological structure and its subsequent cell behaviors. By setting of different 3D printing parameters, i.e. , the 3D printing laser power, the scanning interval and the thickness of sliced layers, the highest resolution up to 20 μm can be precisely fabricated. Scaffolds' characterization results indicated that the laser power affected the forming quality of melt tracks, the scanning interval distance determined the size of regularly arranged pores, and the thickness of sliced layers affected the morphological and structural characteristics. By regulating of these printing parameters, customized porous Ti6Al4V scaffold with varied hierarchical micro-topological structure can be obtained. In vitro cell culturing results showed that the regular porous micro-topological structure of scaffolds with the aperture close to cell size was more suitable for cell proliferation and adhesion. The overall distribution of cells on regular porous scaffolds was similar to the orderly arrangement of cultivated crops in the field. The findings suggested that customization of the scaffold provided an effective way to regulate cellular behavior and biological properties. Scaffold hierarchical microstructures were inspired by the orderly arrangement of cultivated crops in the field, which can be fabricated by adjusting selective laser melting. In 3D printed porous Ti6Al4V scaffolds, regularly arranged macrostructures promote bone tissue ingrowth, and micro-topological structures regulate cell behaviors. Unlabelled Image • Scaffold hierarchical microstructures are inspired by the orderly arrangement of cultivated crops in the field. • Scaffold hierarchical microstructures were customized fabricated by selective laser melting. • Regularly arranged macrostructures in 3D printed porous Ti6Al4V scaffolds promote bone tissue ingrowth. • Micro-topological structures in porous Ti6Al4V scaffolds regulate cell behaviors. [ABSTRACT FROM AUTHOR]

Introduction: Long-term use of chemical fertilizers (CFs) can cause soil compaction and acidification. In recent years, bio-organic fertilizers (BOFs) have begun to replace CFs in some vegetables and cash crops, but the application of CFs or BOFs has resulted in crop quality and disease occurrence., Methods: This study aimed to analyze the microbial mechanism of differences between CFs and BOFs in root disease, quality, and yield of tuber Chinese herbal medicine. We studied the effects of CFs, organic fertilizers, commercial BOFs, biocontrol bacteria BOFs, and biocontrol fungi BOFs on rhizosphere microbial community structure and function, root rot, quality, and yield of Codonopsis pilosula at different periods after application and analyzed the correlation., Results and Discussion: Compared to CFs, the emergence rate and yield in BOF treatments were increased by 21.12 and 33.65%, respectively, and the ash content, water content, and disease index in the BOF treatments were decreased by 17.87, 8.19, and 76.60%, respectively. The structural equation model showed that CFs promoted the quality and yield of C. pilosula by influencing soil environmental factors, while BOFs directly drove soil bacterial community to reduce disease index and improve the quality and yield of C. pilosula . There was a stronger interaction and stability of soil microbial networks after BOF treatments. Microlunatus , Rubrobacter , Luteitalea , Nakamurella , and Pedomicrobium were identified as effector bacteria, which were related to disease prevention and yield and quality increase of C. pilosula . Microbial functional analysis indicated that the signal transduction and amino acid metabolism of soil bacteria might play a major role in improving the quality and yield of C. pilosula in the early and middle growth stages. In conclusion, compared to CFs, BOFs obtained a lower disease index of root rot and a higher quality and yield of C. pilosula by changing the structure and function of the rhizosphere bacterial community., Competing Interests: DL were employed by the Sichuan Provincial Tobacco Company Liangshanzhou Company. HF and CZ were employed by the Shandong Hezhong Kangyuan Biotechnology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Chen, Cao, Liu, Fang, Zhou, Wang and Wang.)

Vascular stents have many applications in treating arterial stenosis and other vascular-related diseases. The ideal vascular stent for clinical application should have radial support and axial bending mechanical properties that meet the requirements of vascular deformation coordination. The materials used for vascular stents implanted in the human body should have corresponding biocompatibility to ensure that the stents do not cause coagulation, hemolysis, and other reactions in the blood. This study fabricated four types of vascular stents, including inner hexagon, arrowhead, quadrilateral, and outer hexagonal, using fused filament fabrication technology and thermoplastic polyurethane (TPU) as materials. By evaluating the effects of edge width and wall thickness on the radial support and axial bending performance, it was found that the inner hexagonal stent exhibited the best radial support and axial bending performance under the same conditions. The design and fabrication of vascular stents based on 3D printing technology have promising application prospects in personalized customized vascular repair therapy.

Near-infrared (NIR) light, compared with ultraviolet (UV) light, has a stronger tissue penetration ability and is widely used in the medical field. However, few hydrogels can be triggered by NIR. Here, a modular polymer-nanosheet (metal disulfide) (PNS) hydrogel system was proposed, which can be photo-crosslinked through photothermal conversion under NIR light. MoS 2 , a transition-metal dichalcogenide, was used as a crosslink center in PNS hydrogels. Mo and S (from thiolated polymers), which are essential for gelation, were discovered to have new bonds. Furthermore, 3D printing of NIR-triggered PNS hydrogels was achieved conceptually with masked NIR. Moreover, multiple hydrogels and metal disulfides were applicable in this modular gelation system. This study indicated that these PNS hydrogels have great potential in many smart biomedical applications, including wearable sensors, noninvasive in vivo 3D bioprinting, and tissue repair substitutes.

Osteoblasts and osteoclasts are two of the most important types of cells in bone repair, and their bone-forming and bone-resorbing activities influence the process of bone repair. In this study, we proposed a physicochemical bidirectional regulation strategy via ration by physically utilizing hydroxyapatite nanopatterning to recruit and induce MSCs osteogenic differentiation and by chemically inhibiting osteolysis activity through the loaded zoledronate. The nanorod-like hydroxyapatite coating was fabricated via a modified hydrothermal process while the zoledronic acid was loaded through the chelation within the calcium ions. The fabrication of a hydroxyapatite/zoledronic acid composite biomaterial. This biomaterial promotes bone tissue regeneration by physically utilizing hydroxyapatite nanopatterning to recruit and induce MSCs osteogenic differentiation and by chemically inhibiting osteolysis activity through the loaded zoledronate. The nanorod-like hydroxyapatite coating was fabricated via a modified hydrothermal process while the zoledronic acid was loaded through the chelation within the calcium ions. The in vitro results tested on MSCs and RAW 246.7 indicated that the hydroxyapatite enhanced cells' physical sensing system, therefore enhancing the osteogenesis. At the same time the zoledronic acid inhibited osteolysis by downregulating the RANK-related genes. This research provides a promising strategy for enhancing bone regeneration and contributes to the field of orthopedic implants.

Cancer stem cells (CSCs) are essential for tumor initiation, recurrence, metastasis, and resistance. However, targeting CSCs as a therapeutic approach remains challenging. Here, a stemness signature based on 22-gene is developed to predict prognosis in esophageal squamous cell carcinoma (ESCC). Staurosporine (STS) is identified as a radioresistance suppressor by high-throughput screening of a library of 2131 natural compounds, leading to dramatically improved radiotherapy efficacy in subcutaneous tumor models. Mechanistically, STS inhibits cell proliferation through the mTOR/AKT signaling pathway and suppressed stemness by targeting ATP-binding cassette A1 (ABCA1), which is transcriptionally regulated by liver X receptor alpha (LXRα). STS can selectively bind to the nucleotide-binding domain (NBD) of ABCA1 and compete for ATP, blocking ABCA1-mediated drug efflux and facilitating intracellular accumulation of STS. Considering the cytotoxicity of STS, an extracellular vesicle-encapsulated STS system (EV-STS) is established for effective STS delivery. EV-STS shows remarkable tumor growth inhibition, even at half the dose of STS, with superior safety and efficacy. These findings indicate that ABCA1 may serve as a predictor of response to neoadjuvant chemotherapy and/or radiotherapy in ESCC patients. EV-STS has shown improved antitumor efficacy and low systemic toxicity, offering a promising therapeutic approach for ESCC., (© 2024 Wiley‐VCH GmbH.)

Numerous studies have shown that there are multiple neural activities involved in the process of bone resorption and bone regeneration, and promoting osteogenesis by promoting neural network reconstruction is an effective strategy for repairing critical size bone defects. However, traumatic bone defects often cause activation of the sympathetic nervous system (SNS) in the damaged area, releasing excess catecholamines (CAs), resulting in a decrease in the rate of bone formation. Herein, a 3D-printed scaffold loaded with propranolol (PRN) is proposed to reduce CA concentrations in bone defect areas and promote bone regeneration through drug release. For this purpose, PRN-loaded methacrylated gelatin (GelMA) microspheres were mixed with low-concentration GelMA and perfused into a 3D-printed porous hydroxyapatite (HAp) scaffold. By releasing PRN, which can block β-adrenergic receptors, it hinders the activation of sympathetic nerves and inhibits the release of excess CA by the SNS. At the same time, the composite scaffold recruits bone marrow mesenchymal stem cells (BMSCs) and promotes the differentiation of BMSCs in the direction of osteoblasts, which effectively promotes bone regeneration in the rabbit femoral condyle defect model. The results of the study showed that the release of PRN from the composite scaffold could effectively hinder the activation of sympathetic nerves and promote bone regeneration, providing a new strategy for the treatment of bone defects.

Severe bone defects resulting from trauma and diseases remain a persistent clinical challenge. In this study, a hierarchical biomimetic microporous hydrogel composite scaffold was constructed by mimicking the hierarchical structure of bone. Initially, gelatin methacrylamide (GelMA) and methacrylic anhydride silk fibroin (SilMA) were synthesized, and GelMA/SilMA inks with suitable rheological and mechanical properties were prepared. Biomimetic micropores were then generated by using an aqueous two-phase emulsification method. Subsequently, biomimetic microporous GelMA/SilMA was mixed with hydroxyapatite (HAp) to prepare biomimetic microporous GelMA/SilMA/HAp ink. Hierarchical biomimetic microporous GelMA/SilMA/HAp (M-GSH) scaffolds were then fabricated through digital light processing (DLP) 3D printing. Finally, in vitro experiments were conducted to investigate cell adhesion, proliferation, and inward migration as well as osteogenic differentiation and vascular regeneration effects. In vivo experiments indicated that the biomimetic microporous scaffold significantly promoted tissue integration and bone regeneration after 12 weeks of implantation, achieving 42.39% bone volume fraction regeneration. In summary, this hierarchical biomimetic microporous scaffold provides a promising strategy for the repair and treatment of bone defects.

The repair of mandibular defects is a challenging clinical problem, and associated infections often hinder the treatment, leading to failure in bone regeneration. Herein, a multifunctional platform is designed against the shortages of existing therapies for infected bone deficiency. 2D Ti 3 C 2 MXene and berberine (BBR) are effectively loaded into 3D printing biphasic calcium phosphate (BCP) scaffolds. The prepared composite scaffolds take the feature of the excellent photothermal capacity of Ti 3 C 2 as an antibacterial, mediating NIR-responsive BBR release under laser stimuli. Meanwhile, the sustained release of BBR enhances its antibacterial effect and further accelerates the bone healing process. Importantly, the integration of Ti 3 C 2 improves the mechanical properties of the 3D scaffolds, which are beneficial for new bone formation. Their remarkable biomedical performances in vitro and in vivo present the outstanding antibacterial and osteogenic properties of the Ti 3 C 2 -BBR functionalized BCP scaffolds. The synergistic therapy makes it highly promising for repairing infected bone defects and provides insights into a wide range of applications of 2D nanosheets in biomedicine.

The commonly used titanium alloy dental implants currently apply solid structures. However, issues such as stress shielding and stress concentration may arise due to the significant difference in elastic modulus between the implant and host. In order to address these problems, this paper proposes five porous structures based on the Gibson-Ashby theoretical model. We utilized selective laser melting technology to shape a porous structure using Ti-6Al-4V material precisely. The mechanical properties of the porous structure were verified through simulation and compression experiments. The optimal porous structure, which best matched the human bone, was a circular ring structure with a pillar diameter of 0.6 mm and a layer height of 2 mm. The stress and strain of the porous implant on the surrounding cortical and cancellous bone under different biting conditions were studied to verify the effectiveness of the optimal circular ring porous structure in alleviating stress shielding in both standard and osteoporotic bone conditions. The results confirm that the circular ring porous structure meets implant requirements and provides a theoretical basis for clinical dental implantation.

Purpose: Large bone defects caused by congenital defects, infections, degenerative diseases, trauma, and tumors often require personalized shapes and rapid reconstruction of the bone tissue. Three-dimensional (3D)-printed bone tissue engineering scaffolds exhibit promising application potential. Fused deposition modeling (FDM) technology can flexibly select and prepare printed biomaterials and design and fabricate bionic microstructures to promote personalized large bone defect repair. FDM-3D printing technology was used to prepare polylactic acid (PLA)/nano β-tricalcium phosphate (TCP) composite bone tissue engineering scaffolds in this study. The ability of the bone-tissue-engineered scaffold to repair bone defects was evaluated in vivo and in vitro., Methods: PLA/nano-TCP composite bone tissue engineering scaffolds were prepared using FDM-3D printing technology. The characterization data of the scaffolds were obtained using relevant detection methods. The physical and chemical properties, biocompatibility, and in vitro osteogenic capacity of the scaffolds were investigated, and their bone repair capacity was evaluated using an in vivo animal model of rabbit femur bone defects., Results: The FDM-printed PLA/nano β-TCP composite scaffolds exhibited good personalized porosity and shape, and their osteogenic ability, biocompatibility, and bone repair ability in vivo were superior to those of pure PLA. The merits of biodegradable PLA and bioactive nano β-TCP ceramics were combined to improve the overall biological performance of the composites., Conclusion: The FDM-printed PLA/nano-β-TCP composite scaffold with a ratio of 7:3 exhibited good personalized porosity and shape, as well as good osteogenic ability, biocompatibility, and bone repair ability. This study provides a promising strategy for treating large bone defects., Competing Interests: The authors report no conflicts of interest in this work., (© 2023 Wang et al.)

Avascular necrosis of the femoral head is a prevalent hip joint disease. Due to the damage and destruction of the blood supply of the femoral head, the ischemic necrosis of bone cells and bone marrow leads to the structural changes and the collapse of the femoral head. In this study, an icariin-loaded 3D-printed porous Ti6Al4V reconstruction rod (referred to as reconstruction rod) was prepared by 3D printing technology. The mechanical validity of the reconstruction rod was verified by finite element analysis. Through infilling of mercapto hyaluronic acid hydrogel containing icariin into the porous structure, the loading of icariin was achieved. The biological efficacy of the reconstruction rod was confirmed through in vitro cell experiments, which demonstrated its ability to enhance MC3T3-E1 cell proliferation and facilitate cellular adhesion and spreading. The therapeutic efficacy of the reconstruction rod was validated in vivo through a femoral head necrosis model using animal experiments. The results demonstrated that the reconstruction rod facilitated osteogenesis and neovascularization, leading to effective osseointegration between bone and implant. This study provides innovative strategy for the treatment of early avascular necrosis of the femoral head. STATEMENT OF SIGNIFICANCE: The bioactivity of medical titanium alloy implants plays an important role in bone tissue engineering. This study proposed a medicine and device integrated designed porous Ti6Al4V reconstruction rod for avascular necrosis of the femoral head, whose macroscopic structure was customized by selective laser melting. The bionic porous structure of the reconstruction rod promoted the growth of bone tissue and formed an effective interface integration. Meanwhile, the loaded icariin promoted new bone and vascular regeneration, and increased the bone mass and bone density. Therefore, the implantation of reconstruction rod interfered with the further development of necrosis and provided a positive therapeutic effect. This study provides innovative strategies for the treatment of early avascular necrosis of femoral head., Competing Interests: Declaration of Interest Statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Microtia is a congenital deformity of the ear with an incidence of about 0.8-4.2 per 10,000 births. Total auricular reconstruction is the preferred treatment of microtia at present, and one of the core technologies is the preparation of cartilage scaffolds. Autologous costal cartilage is recognized as the best material source for constructing scaffold platforms. However, costal cartilage harvest can lead to donor-site injuries such as pneumothorax, postoperative pain, chest wall scar and deformity. Therefore, with the need of alternative to autologous cartilage, in vitro and in vivo studies of biomaterial scaffolds and cartilage tissue engineering have gradually become novel research hot points in auricular reconstruction research. Tissue-engineered cartilage possesses obvious advantages including non-rejection, minimally invasive or non-invasive, the potential of large-scale production to ensure sufficient donors and controllable morphology. Exploration and advancements of tissue-engineered cartilaginous framework are also emerging in aspects including three-dimensional biomaterial scaffolds, acquisition of seed cells and chondrocytes, 3D printing techniques, inducing factors for chondrogenesis and so on, which has greatly promoted the research process of biomaterial substitute. This review discussed the development, current application and research progress of cartilage tissue engineering in auricular reconstruction, particularly the usage and creation of biomaterial scaffolds. The development and selection of various types of seed cells and inducing factors to stimulate chondrogenic differentiation in auricular cartilage were also highlighted. There are still confronted challenges before the clinical application becomes widely available for patients, and its long-term effect remains to be evaluated. We hope to provide guidance for future research directions of biomaterials as an alternative to autologous cartilage in ear reconstruction, and finally benefit the transformation and clinical application of cartilage tissue engineering and biomaterials in microtia treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Huang, Zhao, Wang, Bi, Zhou, Li, Zhou, Wang, Wu, Peng, Tang, Pan, Wang, Chen, Li and Zhang.)

Digital light projection (DLP) printing of hydroxyapatite (HAp) bioceramic provides a promising strategy for fabrication of complex personalized bio-tooth root scaffold with high-resolution. However, it is still a challenge to fabricate bionic bio-tooth root with satisfied bioactivity and biomechanics. This research studied the HAp-based bioceramic scaffold with bionic bioactivity and biomechanics for personalized bio-root regeneration. Compared to natural decellularized dentine (NDD) scaffolds with unitary shape and restricted mechanical properties, those DLP printing bio-tooth roots with natural size, high precision appearance, excellent structure, and a smooth surface were successfully manufactured, which met various shape and structure requirements for personalized bio-tooth regeneration. Moreover, the bioceramic sintering at 1250 °C enhanced the physicochemical properties of HAp and exhibited good elastic modulus (11.72 ± 0.53 GPa), which was almost twice of early NDD (4.76 ± 0.75 GPa). To further improve the surface activity of sintered biomimetic, the nano-HAw (nano-hydroxyapatite whiskers) coating deposited by hydrothermal treatment increased the mechanical properties and surface hydrophilicity, which indicated positive effects on dental follicle stem cells (DFSCs)' proliferation and enhanced the DFSCs osteoblastic differentiation in vitro. Subcutaneous transplantation in nude mice and in-situ transplantation in rat alveolar fossa proved that the nano-HAw-containing scaffold could promote the DFSCs differentiate into periodontal ligament-like enthesis formation. In conclusion, by combining the optimized sintering temperature and modified nano-HAw interface through hydrothermal treatment, the DLP-printing of HAp-based bioceramic with favorable bioactivity and biomechanics is a promising candidate for personalized bio-root regeneration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)