Berberine, a natural compound extracted from several Chinese herbs including Coptis chinensis, has been shown to have anti-obesity effects and prevents insulin resistance in high-fat diet (HFD)-fed obese rats by modulating the gut microbiota; however, the molecular mechanisms underlying these activities remain unknown. We investigated the effects of berberine on obesity and insulin resistance by examining the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4)/tumor necrosis factor (TNF)-α signaling pathway in livers of HFD-fed obese rats. Our results showed that 8-week berberine (200 mg/kg) treatment significantly reduced fasting blood glucose, triglyceride, low-density lipoprotein-cholesterol and insulin resistance in HFD-fed obese rats. However, berberine had no significant effects on body weight, visceral fat mass or the visceral fat to body weight ratio. Berberine also attenuated HFD-induced hepatic steatosis. A prolonged HFD altered the gut microbiota composition by reducing protective bacteria like Bifidobacterium and increasing gram negative bacteria like Escherichia coli, which resulted in increased LPS release into plasma. Berberine reversed these effects and inhibited LPS-induced TLR4/TNF-α activation, resulting in increased insulin receptor and insulin receptor substrate-1 expression in the liver. These findings suggested that berberine may reduce insulin resistance, at least in part by modulating the gut microbiota along with inhibiting LPS/TLR4/TNF-α signaling in the liver.

Poly­(octamethylene carbonate) (POMC), as the eighth member of the newly developed biodegradable aliphatic polycarbonate family, demonstrates a reversible crystal–crystal transition, which is highly similar to Brill transition extensively studied in the nylon family. With the dipole–dipole interaction in POMC much weaker than the hydrogen bonding, POMC exhibits its “Brill transition” temperature at around 42 °C, much lower than nylons. The two crystalline structures of POMC at below and above the transition temperature can be identified. The transition of POMC is largely associated with the reversible conformation change of methylene sequences from trans-dominated at low temperatures to trans/gauche coexistence at high temperatures.

As a class of stimuli-responsive materials, shape memory polymers (SMPs) have received great attention due to their scientific interest and promising applications in advanced technologies in different areas. [1,2] Dual-SMPs can memorize a programmed temporary shape defined by the applied force and fixed by switching the system from one state to the other. Various molecular relaxations and phase transitions, e.g., vitrification, crystallization, or less commonly used liquid crystal (LC) transition, can be employed to fix the temporary shape. It is also demonstrated that multi-SMPs can be fabricated based on multiple transitions or a broad transition. [3] When the reversible transition is triggered by external stimuli, [1,4] the SMP will recover to its permanent shape defined by a network embedded in the system. The network shall be robust enough to resist the plastic deformation when the temporary shape is programmed.The network can be made of chemical or physical crosslink points, leading to SMPs that are thermoset or thermoplastic. [1] While the former gives more stable shape memory performance, the latter is attractive due to the flexibility of processing. However, physical crosslinks based on noncovalent bond interactions, e.g., chain entanglement, hydrogen bond, and ionic interaction, are often less stable. [5] Chain sliding or reorganization occurred during deformation will result in poor shape memory properties. This is a fatal weakness for many thermoplastic SMPs, particularly when a large shape change is demanded, [6] such as in some biomedical devices [2a] and package materials. [6d] To obtain better SMPs combining thermoplastic and stable network, one elegant approach is to follow the strategy of vitrimer. [7a] One can make the network using dynamic covalent bonds, which can allow the SMP to be reshaped at high temperatures with the aid of a catalyst. [7] On the other hand, new thermoplastic SMPs with pure physical crosslink network are still desirable. For example, an excellent multi-SMP of a compositional gradient copolymer is recently reported, [3d] showing a microphase-separated structure similar to the thermoplastic elastomer of styrene-butadiene-styrene (SBS) triblock copolymer. Nevertheless, to make the thermoplastic SMPs with both ideal shape fixity (R f ) and shape recovery (R r ) for high strain (e.g., strain >400%) remains a great challenge. [5,6b] While the commonly applied physical crosslinks show their limitation, we attempt to find a new type of physical crosslink by utilizing a columnar LC structure. Here we report a novel thermoplastic high strain SMP of hemiphasmid sidechain polynorbornene (P1; Figure 1a). P1 exhibits a hexagonal columnar LC (Φ H ) phase and a broad Φ H -isotropic transition. It renders both the R f and R r approaching 100% for dual-shape memory effect (SME), even when a high strain of ≈600% is applied. It is also a multi-SMP. For triple and quadruple-SME, with the total strain higher than 400%, it can still give R f quite high and R r > 95% at each step....

The aim of this study was to evaluate evidence for the efficacy of aloe vera on managing prediabetes and early non-treated diabetes mellitus. We performed a systematic search of PubMed, Embase, and Cochrane Central Register of Controlled Trials until 28 January 2016. A total of five randomized controlled trials (RCTs) involving 415 participants were included. Compared with the controls, aloe vera supplementation significantly reduced the concentrations of fasting blood glucose (FBG) (p = 0.02; weighed mean difference [WMD]: −30.05 mg/dL; 95% confidence interval [CI]: −54.87 to −5.23 mg/dL), glycosylated hemoglobin A1c (HbA1c) (p < 0.00001; WMD: −0.41%; 95% CI: −0.55% to −0.27%), triglyceride (p = 0.0001), total cholesterol (TC) (p < 0.00001), and low density lipoprotein-cholesterol (LDL-C) (p < 0.00001). Aloe vera was superior to placebo in increasing serum high density lipoprotein-cholesterol (HDL-C) levels (p = 0.04). Only one adverse event was reported. The evidence from RCTs showed that aloe vera might effectively reduce the levels of FBG, HbA1c, triglyceride, TC and LDL-C, and increase the levels of HDL-C on prediabetes and early non-treated diabetic patients. Limited evidence exists about the safety of aloe vera. Given the small number and poor quality of RCTs included in the meta-analysis, these results are inconclusive. A large-scale, well-designed RCT is needed to further address this issue.