RESUMO
Obesity has become an important inducer of many public diseases such as diabetes, endocrine disorders, and so on. Anti-obesity treatment has become a hot topic. Inhibiting fat synthesis and promoting fat decomposition are important ways of drug anti-obesity treatment. With the in-depth study of the distribution, morphology and function of adipose tissue, brown adipose tissue containing multi-compartment fat drops and rich mitochondria have attracted people's attention. Beige adipocytes which are similar to brown adipocytes in morphology and function have aroused great interest, such cells can be transformed from white adipocytes by external stimulation or browning agents. This process is called "white fat browning". The expression of promoting energy consumption proteins in these cells increase, so that the function of adipocytes changes from energy storage to energy consumption to increase excessive energy consumption in the body and reduce lipid accumulation. The browning of white adipose tissue has brought new ideas for obesity treatment, but the systemic administration of browning agent has the risk of adverse reactions to non-target tissues such as heart and central nervous system, which limits its application in inducing white fat browning. Browning agents to white adipose tissue can reduce its adverse reactions and improve its bioavailability by constructing a drug delivery system targeting white adipose tissue. In this review, the mechanism on browning of white adipose tissue, the commonly used browning agents and the targeted delivery carriers that induce browning of white adipose tissue are summarized.
RESUMO
An electrochemical analysis system for rapid determination of chemical oxygen demand ( COD) in flow state was established. A planar electrode modified with GO-NiNPs was matched with a 3D printed thin-layer cell. The sample was driven smoothly through the electrode surface by a micro peristaltic pump and then measured by chronoamperometry. The effect of modified materials, dielectric and electrochemical operating conditions were investigated. The whole response time of COD was 1. 5 min and the demand for the sample was about 2 mL. It turned out that the linear range of response in the low concentration region was 0. 15-100 mg/L, the linear equation was i(μA)=3. 974c (mg/L)+0. 2295 (r = 0. 9991) and the detection limit was 0. 04 mg/L. The linear response range in the high concentration region was 100-450 mg/L, and the linear equation was i(μA)=1. 938c (mg/L)+ 230. 9 (r = 0. 9877). Compared with the national standard method (GB11914-89) for measuring the actual water samples (Qinhuai River, Xuanwu Lake and Nanjing tap water), the correlation between them was quite good and the analysis time was dropped to 1/100. This new sensing system provided an environmentally friendly and portable method for detection of COD without using expensive, highly corrosive and toxic reagents.