Galangin and Pinocembrin from Propolis Ameliorate Insulin Resistance in HepG2 Cells via Regulating Akt/mTOR Signaling

Insulin resistance has a critical role in type 2 diabetes. The aim of this study was to investigate the effect of pinobanksin, galangin, chrysin, and pinocembrin from propolis on insulin resistance. Our study shows that galangin and pinocembrin can ameliorate insulin resistance; on the contrary, pinobanksin and chrysin are ineffective. Galangin and pinocembrin treatments substantially increase glucose consumption and glycogen content by enhancing the activities of hexokinase and pyruvate kinase. Galangin treatment with 80 μM increased hexokinase and pyruvate kinase activities by 21.94% and 29.12%, respectively. Moreover, we hypothesize that galangin and pinocembrin may have a synergistic effect on the improvement of insulin resistance via Akt/mTOR signaling pathway, through distinctly upregulating the phosphorylation of IR, Akt, and GSK3β and remarkably downregulating the phosphorylation of IRS. Most notably, this is the first study to our knowledge to investigate pinocembrin about the alleviation of insulin resistance. Our results provide compelling evidence for the depth development of propolis products to ameliorate insulin resistance

Pseudospectral Convex Programming for Free-Floating Space Manipulator Path Planning

To efficiently plan the point-to-point path for a 7-degrees-of-freedom (7-DOF) free-floating space manipulator system, a path planning method based on Legendre pseudospectral convex programming (LPCP) is proposed. First, the non-convex dynamics are approximated by utilizing the first-order Taylor expansion in the vicinity of the initial guess path, which results in a convex system. Next, the linearized dynamics are discretized at Legendre–Gauss–Lobatto collocation points to transcribe the differential equations to a set of equality constraints. To obtain a reliable initial guess trajectory, the auxiliary path planning problem of the 7-DOF space manipulator with a fixed base is initially resolved. Additionally, the penalty function method is introduced to enhance the convergence performance of the LPCP. Finally, simulation results show that the proposed algorithm in this paper can generate the point-to-point path and has higher computational efficiency than the general sequential convex programming method while ensuring optimality

Analysis of Changes and Potential Characteristics of Cultivated Land Productivity Based on MODIS EVI: A Case Study of Jiangsu Province, China

Cultivated land productivity is a basic guarantee of food security. This study extracted the multiple cropping index (MCI) and most active days (MAD, i.e., days when the EVI exceeded a threshold) based on crop growth EVI curves to analyse the changes and potential characteristics of cultivated land productivity in Jiangsu Province during 2001–2017. The results are as follows: (1) The MCI of 83.8% of cultivated land remained unchanged in Jiangsu, the cultivated land with changed MCI (16.2%) was mainly concentrated in the southern and eastern coastal areas of Jiangsu, and the main cropping systems were single and double seasons. (2) The changes in cultivated land productivity were significant and had an obvious spatial distribution. The areas where the productivity of single cropping system changed occupied 67.8% of the total cultivated land of single cropping system, and the decreased areas (46.5%) were concentrated in southern Jiangsu. (3) For double cropping systems, the percentages of the changed productivity areas accounting for cultivated land were 82.7% and 73.3%. The decreased areas were distributed in central Jiangsu. In addition, the productivity of the first crop showed an overall (72%) increasing trend and increased areas (40.8%) of the second crop were found in northern Jiangsu. (4) During 2001–2017, cultivated land productivity greatly improved in Jiangsu. In the areas where productivity increased, the proportions of cultivated land with productivity potential space greater than 20% in single and double cropping systems were greater than 60% and 90%, respectively. In the areas where productivity decreased, greater than 25% and 75% of cultivated land had potential space in greater than 80% of the single and double cropping systems, respectively. This result shows that productivity still has much room for development in Jiangsu. This study provides new insight for studying cultivated land productivity and provides references for guiding agricultural production

A plant origin of Chinese propolis: <i>Populus canadensis</i> Moench

<p>Honey bees make propolis from resins depending on resinous plants available in a particular environment. The aim of this work was to identify the plant origin of Chinese propolis. Through a combination of phytochemical analysis and behavior observation of worker bees, we find that worker bees collected resin on the bud surface of <i>Populus canadensis</i> Moench, and bud resin of <i>P. canadensis</i> presented high similarities between resin in worker bees’ corbiculae and propolis. The results reveal that <i>P. canadensis</i>, a hybrid variety of <i>Populus nigra</i> L. × <i>Populus deltoides</i>, is a plant origin of Chinese propolis. Characteristic components of Chinese propolis included benzyl caffeate, phenethyl caffeate, cinnamyl caffeate, cinnamyl <i>p</i>-cinnamate, pinobanksin-3-acetate, chrysin, pinocembrin, galangin, 5-methoxy pinobanksin, and pinobanksin. These compounds represented more than 80% of the total phenolic contents. This finding will help evaluate the quality and authenticity of poplar type propolis.</p

Analysis of the contribution of land consolidation to sustainable poverty alleviation under various natural conditions

Land consolidation plays a vital role in addressing the global poverty issue. Nevertheless, the factors and mechanisms contributing to the disparities in the impacts of land consolidation on poverty alleviation (LCPA) remain inadequately analyzed. This study aimed to explore how natural conditions influence the effectiveness of LCPA in contiguous impoverished mountainous regions. The structural equation model (SEM), questionnaire and interviews were used to analyze whether natural conditions will affect the effectiveness of LCPA in Wumeng Mountain contiguous poverty-stricken area. The results showed that under the influence of natural conditions, the direct benefits of LCPA decreased by 31.3%, while the indirect benefits decreased by 56.1%. Natural factors have a negative impact on the direct benefits of LCPA, as evidenced by a path coefficient of − 0.39. However, they exhibit a positive influence on the indirect benefits, with a coefficient of 0.57. Specifically, topography and soil have a negative effect on LCPA, but the characteristic hydrological and temperature conditions facilitate the cultivation of specialty crop, such as strawberries and blueberries. The impact of different natural factors on the benefits of LCPA exhibits significant variations. Elevation and precipitation have a pronounced impact on the benefits of LCPA, with path coefficients of 1.01 and 0.99, respectively, while the influence of soil and temperature is relatively limited. While adverse natural conditions are one of the significant factors contributing to poverty, the combination of characteristic climatic conditions and LCPA projects has jointly facilitated the development of agricultural enterprises. Policymakers should pay attention to the multidimensional role of natural factors in land consolidation and poverty alleviation and strengthen the sustainability of land consolidation in poverty alleviation.</p