The contact force between lunar-based equipment and lunar soil.

Lunar-based equipment plays a vital role in the exploration of the moon because it undertakes the tasks of moving, transporting, digging, and so on. In order to control the gait of lunar-based equipment more precisely and guarantee mobile stability, the contact mechanism between its foot and lunar soil is worthy of in-depth study. In this paper, a contact model is proposed to predict the stress, strain, and displacement both on the contact surface and in the lunar soil when the foot is under vertical load. The axial stress in the proposed contact model is verified through the experiment and its accuracy in the lunar equipment is verified through simulation. The error is in a reasonable range and the influence depth of load conforms to the experiment results. This paper provides a relatively accurate model to describe the contact force between the lunar-based equipment's foot and the lunar soil and will promote the research of lunar exploration.

Anti-diabetic effect of Ornithogalum caudatum Jacq. polysaccharides via the PI3K/Akt/GSK-3ß signaling pathway and regulation of gut microbiota.

This study evaluated the anti-diabetic effect of polysaccharides isolated from Ornithogalum caudatum and their underlying mechanisms. To achieve this, a type 2 diabetes mellitus mouse model was established using a combination of a high-fat diet and low-dose streptozotocin injection. The mice were treated with Ornithogalumcaudatum polysaccharides (OCPs) for 4 weeks. OCPs treatment significantly decreased body weight loss, fasting blood glucose levels, and plasma insulin levels in diabetic mice. Additionally, compared with the untreated group, OCPs treatment significantly decreased total cholesterol, triacylglycerol, and low-density lipoprotein-cholesterol levels, but increased those of high-density lipoprotein-cholesterol in diabetic mice. Moreover, antioxidant enzyme activity and histopathology results revealed that OCPs effectively alleviated oxidative stress and streptozotocin-induced lesions by increasing antioxidant enzyme activity. Results from mechanistic studies showed that OCPs treatment significantly increased the expression of p-PI3K, p-Akt, and p-GSK-3ß in the liver. Moreover, OCPs optimized the gut microbiota composition of diabetic mice by significantly decreasing the Firmicutes/Bacteroidetes ratio and increasing the levels of beneficial bacteria (Muribaculaceae_norank, Prevotellaceae_UCG-001 and Alloprevotella). Overall, these findings suggest that OCPs exert anti-diabetic effects by triggering the PI3K/Akt/GSK-3ß signaling pathway and regulating the gut microbiota.

Reduced lung water transport rate associated with downregulation of aquaporin-1 and aquaporin-5 in aged mice.

1. The purpose of the present study was to examine lung water transport properties and the expression and regulation of the alveolar endothelial water channel aquaporin (AQP)-1 and the epithelial water channel AQP-5 in aged mouse lung using gene expression analysis and water permeability measurements. 2. In aged (20-24-month-old) mice, AQP-1 and AQP-5 mRNA expression decreased by 55.5 and 50.3%, respectively, compared with that in young (8-10-week-old) mice (P < 0.01). In addition, AQP-1 and AQP-5 protein expression decreased in aged mice by 36.9 and 44.6%, respectively, compared with that in young mice (P < 0.01). 3. The osmotically driven water transport rate between the airspace and capillary compartments was reduced by 31.7% in aged mice compared with young mice (2.8 +/- 0.3 vs 4.1 +/- 0.3 mg/s, respectively; P < 0.01). The hydrostatically driven lung water accumulation rate in response to a 10 cmH(2)O increase in pulmonary artery pressure was also reduced in aged mice by 21.9% compared with young mice (0.32 +/- 0.06 vs 0.41 +/- 0.04 mg/s, respectively; P < 0.01). 4. There was a 62.7% decrease in serum glucocorticoids in aged mice compared with young mice (67.6 +/- 26.8 vs 181.3 +/- 44.4 nmol/L, respectively; P < 0.01). In vivo administration of dexamethasone (4 mg/kg) for 5 consecutive days to aged mice increased lung AQP-1 mRNA and protein expression by 2.1 +/- 0.1 fold (P < 0.01) and 1.8 +/- 0.2 fold (P < 0.01), respectively. Accordingly, osmotically and hydrostatically driven water transport rates increased by 35.6% (P < 0.01) and 31.2% (P < 0.01), respectively. 5. The present study provides the first evidence of altered lung water transport associated with downregulation of AQPs in aged lung. Blood glucocorticoid hormone levels are important to maintain normal AQP-1 expression in the lung microvascular endothelium. Corticosteroid-induced AQP-1 upregulation may contribute to the role of corticosteroids in accelerating oedema clearance in aged lung.