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Bolt tightening torque has an influence on the fatigue life of the multi-bolted joints which cannot be ignored, but there are few methods to predict the fatigue life of the multi-bolted composite structure by considering the bolt tightening torque. A fatigue life prediction method of the multi-bolted composite structure by considering the bolt tightening torque is proposed. It can take into account the various damages of bolts and laminates and accurately calculate fatigue life and damage evolution of multi-bolted composite structure. The multi-bolted composite structure being composed of T300/BMP-316 composite laminates and TC4 titanium alloy bolts is used to verify the present method. The logarithmic error between the predicted fatigue life and the experimental is 4.36%, and the failure mode is consistent with the experimental. Through the present method, the influence of the bolt tightening torque is explored, in which it is found that with the increasing of bolt tightening torque, the fatigue life increases firstly and decreases, and there is an optimal tightening torque. By observing the damage evolution diagram, it is found that when the tightening torque is below the optimal tightening torque, the damage propagation cannot be effectively restrained, which will lead to the reduction of fatigue life. On the contrary, when the tightening torque is more than the optimal tightening torque, it will cause the initial damage to the test piece, which will also lead to the reduction of fatigue life. In engineering, to choose the best tightening torque of the structure for assembly can effectively improve the fatigue life of the structure.

Bone healing remains a major challenge in the treatment of osteoporosis. Effective strategies that simultaneously promote bone formation and inhibit bone resorption are crucial for the treatment of osteoporosis and associated bone defects. MicroRNA (miRNA)‐based approaches aim at simultaneously promoting bone formation and suppressing bone resorption and have therapeutic potential. However, the toxicity of cationic carriers and off‐target effects are two major challenges associated with miRNA delivery. This study establishes a bone‐targeting miRNA delivery system (CH6‐SNA‐26a) that integrates aggregation‐induced emission (AIE), a CH6 aptamer, and miRNAs into a single nanoplatform without any cationic carrier. In this system, an AIE molecule is coupled to miR‐26a to form a core–shell spherical nucleic acid (SNA‐26a). The CH6 aptamer is co‐assembled with the SNA to achieve specific miR‐26a delivery to the bone surface. This aptamer‐functionalized, non‐cationic miR‐26a delivery strategy (CH6‐SNA‐26a) enables both bone‐targeted delivery and high transfection efficiency, ultimately optimizing bone remodeling and calvarial bone healing in an osteoporosis mouse model while limiting adverse effects in non‐skeletal tissues. Mechanistically, the overexpression of CH6‐SNA‐26a in skeletal tissues promotes bone anabolic action by functionally targeting glycogen synthase kinase 3 beta in bone marrow mesenchymal stem cells and cellular communication network 2 in osteoclasts. [ABSTRACT FROM AUTHOR]

Tumor necrosis factor-alpha (TNF-α) has been shown to cause apoptosis of gingival epithelial cells (GECs) in periodontitis. However, the underlying molecular mechanism is still unclear. In this study, we showed that miR-142 expression was significantly elevated in human GECs after exposure to TNF-α. Such induction was in a time- and concentration-dependent manner. Serum miR-142 levels were positively correlated with serum TNF-α levels in patients with chronic periodontitis ( r = 0.314, P = 0.0152). Depletion of miR-142 was found to attenuate TNF-α-induced apoptosis, as determined by TUNEL staining and caspase-3 activity assays. In contrast, overexpression of miR-142 significantly reduced viability and induced apoptosis in GECs. Basic leucine zipper transcription factor 2 (BACH2) was identified to be a functional target of miR-142. Overexpression of miR-142 caused a 3-fold reduction of BACH2 protein in primary GECs. Overexpression of BACH2 significantly reversed miR-142- or TNF-α-induced apoptosis of GECs. Similar to the findings with miR-142 mimic, depletion of BACH2 significantly promoted apoptosis in GECs, which was accompanied by decreased expression of Bcl-2 and Bcl-xL and increased expression of Bax and Bim. Overall, miR-142 mediates TNF-α-induced apoptosis in gingival epithelial cells by targeting BACH2 and may represent a potential therapeutic target for periodontitis.

The aim of this study was to investigate the impact of a Chinese herbal decoction on the intracellular calcium (Ca2+) concentration of sperm and the expression of the cation channel 1 of sperm (CatSper1), which is a calcium-channel protein specific to sperm tail, in a murine model of asthenospermia induced with cyclophosphamide. After 34 days of intragastric administration of Chinese herb decoction to the murine model used, routine analyses of the mouse sperm were conducted, the intracellular Ca2+ concentration of the sperm tails was measured using flow cytometry, and the expression of CatSper1 protein was detected using reverse transcription‑polymerase chain reaction (RT-PCR). Sperm concentration, percentage of grade A and B sperm (i.e., sperm activity) and percentage of grade A, B and C sperm (i.e., overall sperm motility) of the model group mice (MG) were markedly lower compared to the control murine group (CG) (one-way ANOVA, P<0.05). Subsequent to treatment, sperm concentration, percentage of sperm activity and overall sperm motility of the large dose of herbal medicine group murine (LG) were markedly increased compared to MG mice (P<0.05). Intracellular Ca2+ concentration in MG mice was markedly lower compared to CG mice (P<0.05). However, following therapy, a significant increase was observed in the intracellular Ca2+ concentration in LG mice as compared to MG mice (P<0.05). In addition, the expression of CatSper1 in LG mice was significantly higher compared to MG mice (P<0.05), while no statistically significant difference was observed for the CG mice. Intraperitoneal injection of cyclophosphamide reduced sperm concentration, percentage of sperm activity and overall sperm motility, intracellular Ca2+ concentration and CatSper1 expression. Large doses of this Chinese herbal decoction increased sperm intracellular Ca2+ concentration, sperm concentration, and percentages of sperm activity and overall sperm motility by upregulating CatSper1 expression. The findings of this study have demonstrated a therapeutic effect of this decoction on asthenospermia.