Serendipity discovery of fire early warning function of chitosan film.

Transparent chitosan (CS) film is prepared and its application in high temperature/fire warning is discussed. NaCl-doped chitosan (CS-NaCl) film shows excellent performance in real-time temperature monitoring and fire warning. The temperature warning of CS-NaCl film can be triggered under approximately 50 °C, and it has a good repeatable warning performance under high-temperature conditions. The CS composite film exhibits an ultra-sensitive (0.4 s) warning under fire attacking. A possible electrical conduction and fire-alarm mechanisms are proposed. The addition of NaCl increases the number of charge carriers, which improves the ionic conductivity of the composite film. This study provides a possibility for the application of CS in the field of fire warning.

A high-fat diet and high-fat and high-cholesterol diet may affect glucose and lipid metabolism differentially through gut microbiota in mice.

This study was conducted to investigate the effects of a high-fat diet (HFD) and high-fat and high-cholesterol diet (HFHCD) on glucose and lipid metabolism and on the intestinal microbiota of the host animal. A total of 30 four-week-old female C57BL/6 mice were randomly divided into three groups (n=10) and fed with a normal diet (ND), HFD, or HFHCD for 12 weeks, respectively. The HFD significantly increased body weight and visceral adipose accumulation and partly lowered oral glucose tolerance compared with the ND and HFHCD. The HFHCD increased liver weight, liver fat infiltration, liver triglycerides, and liver total cholesterol compared with the ND and HFD. Moreover, it increased serum high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total cholesterol compared with the ND and HFD and upregulated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase significantly. The HFHCD also significantly decreased the α-diversity of the fecal bacteria of the mice, to a greater extent than the HFD. The composition of fecal bacteria among the three groups was apparently different. Compared with the HFHCD-fed mice, the HFD-fed mice had more Oscillospira, Odoribacter, Bacteroides, and [Prevotella], but less [Ruminococcus] and Akkermansia. Cecal short-chain fatty acids were significantly decreased after the mice were fed the HFD or HFHCD for 12 weeks. Our findings indicate that an HFD and HFHCD can alter the glucose and lipid metabolism of the host animal differentially; modifications of intestinal microbiota and their metabolites may be an important underlying mechanism.

Lactobacilli and bifidobacteria derived from infant intestines may activate macrophages and lead to different IL-10 secretion.

In this study, three strains of lactobacilli and bifidobacteria originally isolated from healthy infants, were tested for their abilities to activate RAW264.7 cells. Gene expression and cytokine production of interleukin-10 (IL-10) of RAW264.7 cells were evaluated. The activation of extracellular regulated protein kinases 1/2 (ERK1/2), p38, and nuclear factor-κB (NK-κB) were also assessed. These results suggest lactobacilli and bifidobacteria in infants may promote production of IL-10 in macrophages, conferring a protective effect in hosts suffering from inflammation. Dimerization of TLR2 and MyD88 and subsequent phosphorylation of the key downstream signaling molecules, such as MAPKs and NK-κB, may be one of the key underlying mechanisms of activation of macrophages by these microbes. Bifidobacteria and lactobacilli induced macrophages to secrete IL-10 in a different manner, which may relate to their abilities to activate key signaling pathways mediated by TLR2 and MyD88.

Numerical Analysis of Airway Mucus Clearance Effectiveness Using Assisted Coughing Techniques.

Cough is a protective respiratory reflex used to clear respiratory airway mucus. For patients with cough weakness, such as chronic obstructive pulmonary disease, neuromuscular weakness disease and other respiratory diseases, assisted coughing techniques are essential to help them clear mucus. In this study, the Eulerian wall film model was applied to simulate the coughing clearance process through a computational fluid dynamics methodology. Airway generation 0 to generation 2 based on realistic geometry is considered in this study. To quantify cough effectiveness, cough efficiency was calculated. Moreover, simulations of four different coughing techniques applied for chronic obstructive pulmonary disease and neuromuscular weakness disease were conducted. The influences of mucus film thickness and mucus viscosity on cough efficiency were analyzed. From the simulation results, we found that with increasing mucus film thickness and decreasing mucus viscosity, cough efficiency improved accordingly. Assisted coughing technologies have little influence on the mucus clearance of chronic obstructive pulmonary disease models. Finally, it was observed that the cough efficiency of the mechanical insufflation-exsufflation technique (MIE) is more than 40 times the value of an unassisted coughing technique, which indicates that the MIE technology has a great effect on airway mucus clearance for neuromuscular weakness disease models.

Insect-scale fast moving and ultrarobust soft robot.

Mobility and robustness are two important features for practical applications of robots. Soft robots made of polymeric materials have the potential to achieve both attributes simultaneously. Inspired by nature, this research presents soft robots based on a curved unimorph piezoelectric structure whose relative speed of 20 body lengths per second is the fastest measured among published artificial insect-scale robots. The soft robot uses several principles of animal locomotion, can carry loads, climb slopes, and has the sturdiness of cockroaches. After withstanding the weight of an adult footstep, which is about 1 million times heavier than that of the robot, the system survived and continued to move afterward. The relatively fast locomotion and robustness are attributed to the curved unimorph piezoelectric structure with large amplitude vibration, which advances beyond other methods. The design principle, driving mechanism, and operating characteristics can be further optimized and extended for improved performances, as well as used for other flexible devices.

Renewable-emodin-based wearable supercapacitors.

With the increasing dependency of human life on wearable electronics, the development of corresponding energy-storage devices is being insensitively pursued. Considering the special usage locations of wearable energy-storage devices, the safety and non-toxicity of electrode materials adopted should be of concern. In this work, a novel all-solid-state wearable supercapacitor based on the renewable-biomolecule emodin, naturally derivable from traditional Chinese herbal rhubarb or Polygonum cuspidatum, was successfully fabricated. Such supercapacitors exhibited excellent charge storage and rate capability with great flexibility and could be integrated into wearable electronics. As a proof of concept, a strap-shaped supercapacitor was fabricated, and it was capable of powering an electronic watch. Our work will promote the development of safe wearable electronics.