Effect of Gut Microbiota on Blood Cholesterol: A Review on Mechanisms.

The gut microbiota serves as a pivotal mediator between diet and human health. Emerging evidence has shown that the gut microbiota may play an important role in cholesterol metabolism. In this review, we delve into five possible mechanisms by which the gut microbiota may influence cholesterol metabolism: (1) the gut microbiota changes the ratio of free bile acids to conjugated bile acids, with the former being eliminated into feces and the latter being reabsorbed back into the liver; (2) the gut microbiota can ferment dietary fiber to produce short-chain fatty acids (SCFAs) which are absorbed and reach the liver where SCFAs inhibit cholesterol synthesis; (3) the gut microbiota can regulate the expression of some genes related to cholesterol metabolism through their metabolites; (4) the gut microbiota can convert cholesterol to coprostanol, with the latter having a very low absorption rate; and (5) the gut microbiota could reduce blood cholesterol by inhibiting the production of lipopolysaccharides (LPS), which increases cholesterol synthesis and raises blood cholesterol.

Metabolites of Gut Microbiota and Possible Implication in Development of Diabetes Mellitus.

Diabetes mellitus is characterized by having a disorder of glucose metabolism. The types of diabetes mellitus include type 1 diabetes mellitus, type 2 diabetes mellitus, gestational diabetes mellitus, and other specific types of diabetes mellitus. Many risk factors contribute to diabetes mellitus mainly including genetics, environment, obesity, and diet.

Life cycle assessment of car sharing models and the effect on GWP of urban transportation: A case study of Beijing.

Alongside a trend in lower private-vehicle ownership and the growing popularity of the shared use economy, car sharing is emerging as an alternative travel mode. The LCA model of car sharing is proposed, the global warming potential (GWP) of four car sharing models is determined, and the effect on GWP of urban transportation is explored. This study expanded the LCA of products to the LCA of services, by expanding the functional unit to service.

Changes of urban nitrogen metabolism in the Beijing megacity of China, 2000-2016.

Rapid growth in metropolitan areas is associated with high nitrogen (N) flows and subsequent environmental and human health consequences. Many studies on the contemporary aspects of urban N metabolism have conducted in recent years, but comprehensive analysis from life cycle perspective is limited. In this study, a detailed quantitative framework for a coupled human-natural N flow model, comprising a full cycle analysis based on the substance flow analysis approach to cover and integrate all specific N flows and stocks associated with N production, consumption and emission, was developed to study the temporal changing patterns of N metabolism in Beijing megacity during 2000-2016.

An optimization method for energy structures based on life cycle assessment and its application to the power grid in China.

The optimization of energy structures, aimed at saving energy and reducing emissions, is an important precautionary measure against climate change. This study considers different environmental impacts of power systems, and investigates ways to optimize power structures and decrease their potential environmental impact. A multi-objectives optimization model of energy structures was created based on life cycle assessment (LCA).

Trace elements distribution and ecological risk assessment of seawater and sediments from Dingzi Bay, Shandong Peninsula, North China.

Selected trace elements (Hg, As, Pb, Cu, Cd, Cr and Zn) in seawater and sediments from Dingzi Bay, a semi-enclosed bay suffering from severe degradation located in the Shandong Peninsula, were investigated to evaluate the spatial distribution and potential ecological risk. Results indicated that higher concentrations occurred in the inner bay. Calculation of pollution load index (PLI) showed overall low values while the concentration factor (CF) indicated that Hg, As and Cd were at moderate risk levels in the region.