Dietary Restriction Reduces Blood Lipids and Ameliorates Liver Function of Mice with Hyperlipidemia

Dietary restriction（DR） can delay senescence, prolong lifespan of mammals and improve their learning-memory activity. The purpose of the study was to explore the effects of DR on hypolipidemic action and liver function of mice with hyperlipidemia. To investigate these effects, hyperlipidemia mouse models were established with high-fat diet（HFD）（34% of energy）, then randomly divided into HFD group, DR30% group and DR50% group. Mice in DR30% and DR50% group were respectively supplied with HFD as much as about 70% and 50% of the consumption of HFD in the mice of HFD group. Rats in control group were fed routinely. After DR for 5 weeks, the average body weight, liver weight, liver index, serum lipids and glucose levels in both DR groups decreased significantly as compared with the HFD group（P〈0.05 or P〈0.01）, so did alanine aminotransferase（ALT）, aspartate aminotransferase（AST）, lactate dehydrogenase（LDH） levels and the ratio of LDL-C/HDL-C in the DR50% group（P〈0.05 or P〈0.01）. Histopathology examination of liver tissues further proved ameliorative effect of DR on liver function. Western blotting showed that DR significantly increased the expression of silent mating type information regulation 2 homolog 1（SIRT1） in liver and adipose, while notably decreased the expression of peroxisome proliferators-activated receptors-gamma（PPARγ） in adipose（P〈0.05 or P〈0.01）. The increase of SIRT1 and decrease of PPARγ may be a mechanism by which DR reduces blood lipids and ameliorates liver function.

Most probable transition paths in eutrophicated lake ecosystem under Gaussian white noise and periodic force

The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable transition paths to characterize the regime shifts.The most probable transition paths are obtained by minimizing the Freidlin-Wentzell(FW)action functional and Onsager-Machlup(OM)action functional,respectively.The most probable path shows the movement trend of the lake eutrophication system under noise excitation,and describes the global transition behavior of the system.Under the excitation of Gaussian noise,the results show that the stability of the eutrophic state and the oligotrophic state has different results from two perspectives of potential well and the most probable transition paths.Under the excitation of Gaussian white noise and periodic force,we find that the transition occurs near the nearest distance between the stable periodic solution and the unstable periodic solution.

A Minimizing Property of Homographic Solutions

In this paper, we prove that the homographic solutions to the rhombus four body prob- lem are the variational minimizers of the Lagrangian action restricted on a holonomically constrained rhombus loop space.