In Situ Photoactivated Antibacterial and Antioxidant Composite Materials to Promote Bone Repair.

Trauma and tumor removal usually cause bone defects; in addition, the related postoperative infection also shall be carefully considered clinically. In this study, polylactic acid (PLLA) composite fibers containing Cerium oxide (CeO2) are first prepared by electrospinning technology. Then, the PLLA/CeO2@PDA/Ag composite materials are successfully prepared by reducing silver ion (Ag+) to nano-silver (AgNPs)  coating in situ and binding AgNPs to the materials surface by mussel structure liked polydopamine (PDA). In the materials, Ag+ can be slowly released in simulated body fluids. Based on the photothermal performance of AgNPs, the photothermal conversion efficiency of the materials is 21%, under NIR 808 nm illumination. The effective photothermal conversion can help materials fighting with E. coli and S. aureus in 3 h, with an antibacterial rate of 100%. Additionally, the sustained Ag+ release contributes to the antibacterial in long term. Meanwhile, the materials can mimic the bio-behavior of superoxide dismutase and catalase in decreasing the singlet oxygen level and removing the excess reactive oxygen species. Furthermore, the materials are beneficial for cell proliferation and osteogenic differentiation in vitro. In this study, a promising bone-regenerated material with high photothermal conversion efficiency and antibacterial and anti-oxidation properties, is successfully constructed.

Association Analysis of Triglyceride Glucose-Body Mass Index and Bone Turnover Markers in Patients with Type 2 Diabetes Mellitus.

Objective: In view of the high prevalence of osteoporosis in diabetic patients, this study aimed to investigate the correlation between TyG-BMI, which represents insulin resistance, and bone loss markers, which represent bone metabolism, in an attempt to provide new ideas for the early prevention and diagnosis of osteoporosis in patients with T2DM. Patients and Methods: A total of 1148 T2DM were enrolled. The clinical data and laboratory indicators of the patients were collected. TyG-BMI was calculated based on fasting blood glucose (FBG), triglycerides (TG), and body mass index (BMI) levels. Patients were divided into Q1-Q4 groups according to TyG-BMI quartiles. According to gender, two groups were divided into men and postmenopausal women. Subgroup analysis was performed according to age, course of disease, BMI, TG level and 25(OH)D3 level. The correlation between TyG-BMI and BTMs was investigated by correlation analysis and multiple linear regression analysis using SPSS25.0 statistical software. Results: 1. Compared with Q1 group, the proportion of OC, PINP and ß-CTX in Q2, Q3 and Q4 groups decreased significantly. 2. Correlation analysis and multiple linear regression analysis showed that TYG-BMI was negatively correlated with OC, PINP and ß-CTX in all patients and male patients. In postmenopausal women, TyG-BMI was negatively correlated with OC and ß-CTX, but not with PINP. 3. Subgroup analysis of male patients and postmenopausal female patients according to age, course of disease, BMI, TG and 25(OH)D3 showed that TyG-BMI had a stronger negative correlation with BTMs in male patients with age < 65, disease duration < 10, BMI≥24, TG < 1.7, and 25(OH)D3≥20. Conclusion: This study was the first to show an inverse association between TyG-BMI and BTMs in T2DM patients, suggesting that high TyG-BMI may be associated with impaired bone turnover.

Rectal bacteria produce sex pheromones in the male oriental fruit fly.

Volatile molecules produced by the microbiota play a primary role in chemical communication between insects,1 and direct production of pheromone components by the microbiota is one of the most obvious mechanisms.2 Here, we investigated the production of male-borne sex pheromones of the oriental fruit fly, Bactrocera dorsalis. As observed in previous studies,3,4 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) are sex pheromones produced in the male rectum. Mature virgin females are strongly attracted to TMP and TTMP. 16S rRNA sequencing results show that the rectal bacteria are dominated by Bacilli that harbor the pathway to produce TMP and TTMP.5-8 The levels of Bacilli, TMP, and TTMP in the male rectum can be significantly decreased by feeding male flies with antibiotics. In vitro assays show that Bacillus species isolated from the male rectum can produce TMP and TTMP when provided with the substrates glucose and threonine, the levels of which are significantly higher in the rectum of mature males. These findings highlight the influence of microbial symbionts on insect pheromones and provide an example of direct bacterial production of pheromones in insects.

Generation and characterization of ultra-precision compound freeform surfaces.

Compound freeform surfaces are widely used in bionic and optical applications. The manufacturing and measurement of such surfaces are challenging due to the complex geometry with multi-scale features in a high precision level with sub-micrometer form accuracy and nanometer surface finish. This article presents a study of ultra-precision machining and characterization of compound freeform surfaces. A hybrid machining process by combining slow slide servo and fast tool servo is proposed to machine compound freeform surfaces. The machining process for this hybrid tool servo is explained, and tool path generation is presented. Then, a normal template-based matching and characterization method is proposed to evaluate such compound freeform surfaces. Experimental studies are undertaken to machine a compound freeform surface using the proposed method based on a four-axis ultra-precision machine tool. The machined compound freeform surface is also measured and characterized by the proposed analysis and characterization method. The experimental results are presented, and the machining errors for compound freeform surfaces are also discussed.

Antibacterial and osteoinductive biomacromolecules composite electrospun fiber.

Bone implant materials have been widely used in bone therapy. However, bone infections caused by bacteria can damage the healing and repairing ability of bone tissue, which remains a major problem to be solved in clinical bone regeneration with implants. In this study, silver nanoparticles (Ag-NPs) were uniformly distributed on the inner of Polylactic acid and Gelatin composite fibers (PLLA and Gel, biological macromolecules) by co-electrospinning for improving anti-infection ability and osseointegration. The optimized experimental conditions for this method were having PLLA/Gel mass ratio of 90:10 and Ag content of 7%. Ag-NPs acted as heterogeneous nucleation sites for promoting the nucleation and growth of calcium phosphorus on the surface of composite fiber. Bone marrow-derived mesenchymal stem cells adhered and proliferated well on the surface of the composite fiber, and the positive fluorescence staining indicated the existence of osteoblasts. Vascular endothelial cells had a good adherence and proliferation on the surface of composite fiber, showing good angiogenic properties. Antibacterial rate of the composite fiber was all over 97% against Monilia albicans, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, showing good antibacterial property. A multi-functional biomacromolecules composite fiber was constructed and shown good bioactivity, osteoinductivity, angiogenic and antibacterial properties.