Search

Background and objectivePCOS is a common metabolic disorder in women of reproductive age, which pathogenesis is very complex. The role of ferroptosis in PCOS is a novel finding, and the mechanistic studies are not clear. Metformin is a commonly used drug of PCOS but few studies on whether metformin can improve the follicle development and ovarian function in PCOS. We aims to use PCOS mouse model to study the effect of metformin on PCOS based on the ovarian function and explored the regulation of metformin in PCOS mice by intervening in ferroptosis pathway.Materials and methodsC57 BL/6J female mice aged 4-5 weeks were purchased and gavaged with letrozole (1 mg/kg/day) combined with high-fat diet for 21days to establish PCOS model, and control group was set up. After modeling, the mice were divided into PCOS model group and metformin treatment group (Met) (n=6).The Met group were gavaged metformin (200 mg/kg/day) for 28 days. The body weight, estrous cycle, glucose tolerance test (OGTT)and insulin resistance test (ITT) were monitored. Then, The mice were euthanized to collect serum and ovaries. Elisa was used to detect changes in related serum hormones (E2, LH, FSH, TP). Ovaries used for molecular biology experiments to detect changes in GPX4, SIRT3, AMPK/p-AMPK, and mTOR/p-mTOR by Western blot and qPCR.ResultsCompared with the model group mice, body weight was significantly reduced, and their estrous cycle was restored in Met group. The results of OGTT and ITT showed an improvment of glucose tolerance and insulin resistance. Morphological results showed that after metformin treatment, polycystic lesions in ovaries were reduced, the ovarian function was restored, and the expressions of SIRT3 and GPX4 were elevated. WB results demonstrated that the expressions of p-mTOR and p-AMPK in ovaries were significantly reduced in Model group, but reversed in MET group.ConclusionOur study confirmed metformin could not only improve body weight and metabolism disorders, but also improve ovarian dysfunction in PCOS mice.In addition, we explored metformin could regulate ferroptosis to improve PCOS via the SIRT3/AMPK/mTOR pathway. Our study complements the mechanisms by which metformin improves PCOS.

Cellulose is the most abundant biorenewable resource on the earth, and is also characterized by its low price, easy derivatization and good biodegradable property. It is believed that derivatization is an important strategy to extend its applications. Cellulose carbonate is one of the most important classes of cellulose derivatives, as they have good potential in the field of green packaging film materials, thermoplastics, solid electrolyte, and so on. In this study, cellulose methyl carbonate has been synthesized successfully after the dissolution of cellulose in the novel 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/DMSO/CO2 system followed by the addition of dimethyl carbonate via the in-situ organocatalysis by DBU. The structure and thermal properties of the as prepared cellulose methyl carbonate were systematically characterized by NMR, FTIR, TGA and DSC. The results show that cellulose methyl carbonate with a DS of 1.09 was achieved after 12 h at 60 °C with molar ratio of dimethyl carbonate/AGU at 8:1. The DSC/TGA results show that the cellulose methyl carbonate with DS=1.09 has a T g of 62.9 °C and starts thermal degradation at 305.5 °C .

The purpose of this study is to investigate the effect of the coefficient of excess air to the performance of engine. Through a series of the sea trials for newly built ships, the factors that have a great influence of engine’s performance are determined. In addition, methods of raising the coefficient of excess air are proposed to reduce the thermal load and accordingly enhance the performance of diesel engine. Finally, to achieve an efficient operation of the main engine, an example of trouble shooting and maintenance of the engine is given for practical applications. The scavenging pressure increased from 0.162 MPa to 0.207 MPa and the average exhaust temperature dropped from 423°C to 336°C under 90% load condition.

Based on the mass conservation law, the growth rate program for shortening the initial transient length of the Bridgman-Stockbarger method is derived. A theoretical analysis shows that the crystal homogeneity can be largely raised without reducing the productivity by using this growth rate program.