The Promotion of Mechanical Properties by Bone Ingrowth in Additive-Manufactured Titanium Scaffolds

Although the initial mechanical properties of additive-manufactured (AM) metal scaffolds have been thoroughly studied and have become a cornerstone in the design of porous orthopaedic implants, the potential promotion of the mechanical properties of the scaffolds by bone ingrowth has barely been studied. In this study, the promotion of bone ingrowth on the mechanical properties of AM titanium alloy scaffolds was investigated through in vivo experiments and numerical simulation. On one hand, the osseointegration characteristics of scaffolds with architectures of body-centred cubic (BCC) and diamond were compared through animal experiments in which the mechanical properties of both scaffolds were not enhanced by the four-week implantation. On the other hand, the influences of the type and morphology of bone tissue in the BCC scaffolds on its mechanical properties were investigated by the finite element model of osseointegrated scaffolds, which was calibrated by the results of biomechanical testing. Significant promotion of the mechanical properties of AM metal scaffolds was only found when cortical bone filled the pores in the scaffolds. This paper provides a numerical prediction method to investigate the effect of bone ingrowth on the mechanical properties of AM porous implants, which might be valuable for the design of porous implants

Somatic mutation and gain of copy number of PIK3CA in human breast cancer

INTRODUCTION: Phosphatidylinositol 3-kinases (PI3Ks) are a group of lipid kinases that regulate signaling pathways involved in cell proliferation, adhesion, survival, and motility. Even though PIK3CA amplification and somatic mutation have been reported previously in various kinds of human cancers, the genetic change in PIK3CA in human breast cancer has not been clearly identified. METHODS: Fifteen breast cancer cell lines and 92 primary breast tumors (33 with matched normal tissue) were used to check somatic mutation and gene copy number of PIK3CA. For the somatic mutation study, we specifically checked exons 1, 9, and 20, which have been reported to be hot spots in colon cancer. For the analysis of the gene copy number, we used quantitative real-time PCR and fluorescence in situ hybridization. We also treated several breast cancer cells with the PIK3CA inhibitor LY294002 and compared the apoptosis status in cells with and without PIK3CA mutation. RESULTS: We identified a 20.6% (19 of 92) and 33.3% (5 of 15) PIK3CA somatic mutation frequency in primary breast tumors and cell lines, respectively. We also found that 8.7% (8 of 92) of the tumors harbored a gain of PIK3CA gene copy number. Only four cases in this study contained both an increase in the gene copy number and a somatic mutation. In addition, mutation of PIK3CA correlated with the status of Akt phosphorylation in some breast cancer cells and inhibition of PIK3CA-induced increased apoptosis in breast cancer cells with PIK3CA mutation. CONCLUSION: Somatic mutation rather than a gain of gene copy number of PIK3CA is the frequent genetic alteration that contributes to human breast cancer progression. The frequent and clustered mutations within PIK3CA make it an attractive molecular marker for early detection and a promising therapeutic target in breast cancer

All-Trans Retinoic Acid Promotes TGF-β-Induced Tregs via Histone Modification but Not DNA Demethylation on Foxp3 Gene Locus

It has been documented all-trans retinoic acid (atRA) promotes the development of TGF-β-induced CD4(+)Foxp3(+) regulatory T cells (iTreg) that play a vital role in the prevention of autoimmune responses, however, molecular mechanisms involved remain elusive. Our objective, therefore, was to determine how atRA promotes the differentiation of iTregs.Addition of atRA to naïve CD4(+)CD25(-) cells stimulated with anti-CD3/CD28 antibodies in the presence of TGF-β not only increased Foxp3(+) iTreg differentiation, but maintained Foxp3 expression through apoptosis inhibition. atRA/TGF-β-treated CD4(+) cells developed complete anergy and displayed increased suppressive activity. Infusion of atRA/TGF-β-treated CD4(+) cells resulted in the greater effects on suppressing symptoms and protecting the survival of chronic GVHD mice with typical lupus-like syndromes than did CD4(+) cells treated with TGF-β alone. atRA did not significantly affect the phosphorylation levels of Smad2/3 and still promoted iTreg differentiation in CD4(+) cells isolated from Smad3 KO and Smad2 conditional KO mice. Conversely, atRA markedly increased ERK1/2 activation, and blockade of ERK1/2 signaling completely abolished the enhanced effects of atRA on Foxp3 expression. Moreover, atRA significantly increased histone methylation and acetylation within the promoter and conserved non-coding DNA sequence (CNS) elements at the Foxp3 gene locus and the recruitment of phosphor-RNA polymerase II, while DNA methylation in the CNS3 was not significantly altered.We have identified the cellular and molecular mechanism(s) by which atRA promotes the development and maintenance of iTregs. These results will help to enhance the quantity and quality of development of iTregs and may provide novel insights into clinical cell therapy for patients with autoimmune diseases and those needing organ transplantation

Stress-dependent design and optimization methodology of gradient porous implant and application in femoral stem

Gradient porous structure made by additive manufacturing (AM) technology is potential to improve the long-term stability of orthopaedic implants through bone ingrowth while maintaining mechanical safety. In this study, a parametrical optimization methodology for the customized gradient porous implants was developed based on a stress-dependent design algorithm. Clinical requirements and manufacturing capabilities of AM were considered in the design procedure. A femoral stem with a minimum bone loss proportion of 2.4% by optimizing the control parameters. This study provided a feasible and flexible design approach for the customized implant with gradient porous structure or material components

Synthesis and performance of a novel high-efficiency coal dust suppressant based on biopolysaccharide-xanthan gum

The coal production process produces a lot of dust, which pollutes the environment and threatens the occupational health of workers. Although many dust suppressants for coal dust control have been developed, the implementation of current dust suppressants does not meet the requirements due to their poor foaming, stability, and wettability effects. In our current study, the effect of xanthan gum (XG) on the properties and foaming ability of the composite surfactant ALAP has been investigated. The research shows that with the increase of CXG, the foaming volume of the solution increases by nearly 30% on average. The liquid-carrying capacity, the foaming delay period, and the liquid-draining half-life of the foam are also improved, while the performance of wetting coal dust decreases. Compared with traditional water-soluble polymers, XG molecules have a special double helix structure and plenty of polar functional groups, which can form a stable 3D network system with surfactant molecules. XG molecules could not only effectively improve the foaming performance of low-concentration ALAP, the liquid-carrying ability, and the stability of foam, but also reduce the burst rate of the bubbles. In our investigations, the dust reduction effect of the XG/ALAP systems have been comprehensively evaluated through the field application of the heading face. The dust reduction efficiency of total dust and respirable dust can reach nearly 90% and 85% respectively, which is 2.2 times and 2.5 times higher than that of water spraying. The XG/ALAP systems also effectively improve the visibility of the working surface. With the consideration of all the above-mentioned factors, the composition range of the high-efficiency dust suppressant is obtained as: 0.7‰≥CXG ≥ 0.5‰ and 4‰≥CALAP ≥ 3‰.This project was supported by the Key Program of the National Natural Science Foundation of China (Grant No. 52130411), the National Natural Science Foundation of China (Grant No. 51974299) and the Fundamental Research Funds for the Central Universities (Grant No. 2020CXNL10). Jian Gan was supported by the China Scholarship Council (Grant No. 202006420018)

Experimental and molecular dynamics investigations of the effects of ionic surfactants on the wettability of low-rank coal

The wetting properties of ALES (Ammonium lauryl ether sulfate), SLES (sodium lauryl ether sulfate), TD (dodecyl triethanolamine salfate) and SDS (sodium dodecyl sulfate) solutions and their adsorption capacities on coal dust surface were evaluated by surface tension, contact angle, sink time, wetting rate, and changes in the micromorphology and functional groups on coal surface. The results showed that the four surfactants share similar adhesion and spreading wettability, while they differ notably in immersion wetting. A water-surfactant-low rank coal (LRC) system was established using Materials Studio software and the Wender coal model; then quantum chemical calculations and molecular dynamics (MD) simulations were conducted. The results showed that ALES is of the widest relative concentration distribution range (25.25–60 Å), the largest overlap range (25 Å) and the largest diffusion coefficient (D = 0.318); NH4+ can easily penetrate the surfactant layer, which proves the strong modification ability of ALES to LRC. ALES/LRC/H2O has the lowest interaction energy and the most H-bonds, indicating that ALES is of a strong adsorption capacity. Based on the experimental data and simulation results, the integrated wettabilities of the four surfactants follow ALES＞SLES＞TD＞SDS, partially contributed by the hydrolytic cations and EO groups.This project was supported by the Key Program of the National Natural Science Foundation of China (Grant No. 52130411), the National Natural Science Foundation of China (Grant No. 51974299), and the Fundamental Research Funds for the Central Universities (2020CXNL10). Jian Gan was supported by the China Scholarship Council (Grant No. 202006420018)

Hierarchical and Highly Stable Conductive Network Cathode for Ultraflexible Li–S Batteries

Flexible Li–S batteries have great potential for next-generation energy storage which can meet the rising demand of rollable displays and wearable electronic devices because of the high theoretical energy density and competitive price. Here, we design and fabricate an integrated electrode with hierarchical structure and interconnected 3D conductive networks as a cathode of flexible Li–S batteries. The composite cathode exhibits high electrochemical performance and cycling stability. The initial reversible discharge capacity is 1312 mA h g^–1 at 0.2 C with sulfur load 2.0 mg cm^–2, and the capacity decay rate is 0.09% per cycle within 500 cycles at current of 1 C. Notably, the composite electrode can sustain 15.2 MPa stress with 10% strain and retain structural integrity after 200 000 bending cycles, the highest number of bending cycles found to date for any flexible S cathodes. The soft package batteries with different sizes and shapes are fabricated, and they exhibit extraordinary flexibility and stability after bending and flattening over 2100 times. Moreover, their potential applications in rollable displays, flexible lighting, and wearable electronic devices are also investigated

Hierarchical and Highly Stable Conductive Network Cathode for Ultraflexible Li–S Batteries

Flexible Li–S batteries have great potential for next-generation energy storage which can meet the rising demand of rollable displays and wearable electronic devices because of the high theoretical energy density and competitive price. Here, we design and fabricate an integrated electrode with hierarchical structure and interconnected 3D conductive networks as a cathode of flexible Li–S batteries. The composite cathode exhibits high electrochemical performance and cycling stability. The initial reversible discharge capacity is 1312 mA h g^–1 at 0.2 C with sulfur load 2.0 mg cm^–2, and the capacity decay rate is 0.09% per cycle within 500 cycles at current of 1 C. Notably, the composite electrode can sustain 15.2 MPa stress with 10% strain and retain structural integrity after 200 000 bending cycles, the highest number of bending cycles found to date for any flexible S cathodes. The soft package batteries with different sizes and shapes are fabricated, and they exhibit extraordinary flexibility and stability after bending and flattening over 2100 times. Moreover, their potential applications in rollable displays, flexible lighting, and wearable electronic devices are also investigated

Synthesis of an emerging morpholine-typed Gemini surfactant and its application in reverse flotation carnallite ore for production of potash fertilizer at low temperature

Carnallite is a kind of high-quality source of raw material for the production of potash fertilizer (KCl) in industry. However, how to produce potash fertilizer sustainably at low temperature has always been a problem. In this work, we synthesized an emerging morpholine-typed Gemini surfactant, butanediyl-α, ω-bis (morpholino dodeculammonium bromide) (BM), which can be used to collect NaCl in reverse flotation carnallite ores in a low-temperature environment. We compared its ability to collect NaCl and carnallite with the monomeric surfactant 4-laurylmorpholine (LM) at low temperatures. The flotation test results indicated that BM has a stronger collecting ability for NaCl than that of conventional LM collector. At room temperature (25 °C), BM exhibits a forceful collecting function to NaCl and preeminent selectivity for carnallite. The recovery of NaCl ran up to 98.0% when the concentration of BM was 1 × 10 mol/L. Under the same condition, the flotation recovery using LM was only 39.0%. The recoveries of carnallite of the two were not more than 3.5%. When the environment temperature descended, the effect of BM for NaCl exhibited a stronger stable trend. The recovery with BM as a collector raised notably from 68.0% to 96.5% with temperature ranging from 0 °C to 15 °C. However, in the same scope of dosage and temperature, the recovery with LM collector only raised from 3.5% to 31.5%. At 0 °C, LM lost the vast majority of its collector performance, while BM still showed high performance