Hepatic-Specific FGF21 Knockout Abrogates Ovariectomy-Induced Obesity by Reversing Corticosterone Production.

Increased glucocorticoid (GC) levels act as a master contributor to central obesity in estrogen-depleted females; however, what factors cause their increased GC production is unclear. Given (1) liver fibroblast growth factor 21 (FGF21) and GCs regulate each other's production in a feed-forward loop, and (2) circulating FGF21 and GCs are parallelly increased in menopausal women and ovariectomized mice, we thus hypothesized that elevation of hepatic FGF21 secretion causes increased GGs production in estrogen-depleted females. Using the ovariectomized mice as a model for menopausal women, we found that ovariectomy (OVX) increased circulating corticosterone levels, which in turn increased visceral adipose Hsd11b1 expression, thus causing visceral obesity in females. In contrast, liver-specific FGF21 knockout (FGF21 LKO) completely reversed OVX-induced high GCs and high visceral adipose Hsd11b1 expression, thus abrogating OVX-induced obesity in females. Even though FGF21 LKO failed to rescue OVX-induced dyslipidemia, hepatic steatosis, and insulin resistance. What's worse, FGF21 LKO even further exacerbated whole-body glucose metabolic dysfunction as evidenced by more impaired glucose and pyruvate tolerance and worsened insulin resistance. Mechanically, we found that FGF21 LKO reduced circulating insulin levels, thus causing the dissociation between decreased central obesity and the improvement of obesity-related metabolic syndromes in OVX mice. Collectively, our results suggest that liver FGF21 plays an essential role in mediating OVX-induced central obesity by promoting GC production. However, lack of liver FGF21 signaling reduces insulin production and in turn causes the dissociation between decreased central obesity and the improvement of obesity-related metabolic syndromes, highlighting a detrimental role for hepatic FGF21 signals in mediating the development of central obesity but a beneficial role in preventing metabolic abnormality from further exacerbation in estrogen-depleted females.

Simplified Calculation Model and Experimental Validation of the Force Transfer Ratio of Steel-Concrete Joint of Hybrid Box Girder.

The axial force transfer ratio of steel-concrete joints in hybrid box girder bridges is crucial for bridge design. However, the current standard oversimplifies the transfer ratio distribution coefficients, and both model tests and finite element analysis are time- and labor-intensive. This article proposes a simplified calculation model based on the deformation coordination theory to estimate the transfer ratio of the axial force between the bearing plate and shear connectors of the steel-concrete joint under compression bending conditions. Additionally, a large-scale model (1/5 scale) is established, and the mechanical properties of the steel-concrete joint section under compression-bending conditions are experimentally tested. A three-dimensional finite element model is developed and verified using the obtained test data. Results confirm the favorable mechanical properties and ample safety reserve of the SCJ, with all components remaining within the elastic stage under 1.6 times design conditions. By comparing the axial force transfer ratios obtained from the simplified calculation model and the finite element model, a small difference is observed, validating the reliability of the simplified calculation model. This paper provides a straightforward and efficient method for the design and evaluation of steel-concrete joints in hybrid box girder bridges.

Phosphonium-based deep eutectic solvent coupled with vortex-assisted liquid-liquid microextraction for the determination of benzoylurea insecticides in olive oil.

In this study, a novel method using a phosphonium-based deep eutectic solvent coupled with vortex-assisted liquid-liquid microextraction was investigated for the enrichment and separation of five benzoylurea insecticides in olive oil. The experimental factors affecting the extraction efficiency, including the extractant type, deep eutectic solvent volume, extraction time, and extraction mode, were optimized. Under optimal conditions, good linearity was observed for all target analytes, with correlation coefficients (r) ranging from 0.9971 to 0.9998; the limits of detection were in the range of 1.5 to 7.5 µg/L, and the recoveries of analytes using the proposed method ranged between 66.9 and 111.0%. The simple, rapid, and effective method was successfully applied for detecting target analytes in olive oil sample.