Because of their readiness and high power bandwidth, batteries are the preeminent source of power supply for portable electronics, but are subject to periodic recharging and replacement. Hence, a key challenge is to design suitable and sustainable power sources for portable electronic devices. Harvesting energy from the human body is suitable for providing consistent and uninterrupted energy for wearable electronic devices. The daily activities of a 68-kg adult can generate over 100 W of power, through breathing, heating, blood transport, and walking. [3] Thus, converting 1% of the power generated by the human body may be enough to support the work of most portable electronics. Various energy-harvesting technologies, such as, triboelectric nanogenerators (TENGs), [4][5][6] piezoelectric nanogenerators, [7] and thermoelectric generators (TEGs), [8] have been developed to convert human energy (from human motion and body heat) into electricity. In line with recent developments in wearable electronics and e-skins, the use of a self-powered direct-current (DC) electric power supplier is inevitable for activating human body-adjustable electronic systems. [9] Among the various energy-autonomous devices, [10] only TEGs can permanently produce DC electric power without complex power managing components, and they are maintenance free. Moreover, solar energy and vibration-based energy harvesters areThe emergence of artificial intelligence and the Internet of Things has led to a growing demand for wearable and maintenance-free power sources. The continual push toward lower operating voltages and power consumption in modern integrated circuits has made the development of devices powered by body heat finally feasible. In this context, thermoelectric (TE) materials have emerged as promising candidates for the effective conversion of body heat into electricity to power wearable devices without being limited by environmental conditions. Driven by rapid advances in processing technology and the performance of TE materials over the past two decades, wearable thermoelectric generators (WTEGs) have gradually become more flexible and stretchable so that they can be used on complex and dynamic surfaces. In this review, the functional materials, processing techniques, and strategies for the device design of different types of WTEGs are comprehensively covered. Wearable self-powered systems based on WTEGs are summarized, including multi-function TE modules, hybrid energy harvesting, and all-in-one energy devices. Challenges in organic TE materials, interfacial engineering, and assessments of device performance are discussed, and suggestions for future developments in the area are provided. This review will promote the rapid implementation of wearable TE materials and devices in self-powered electronic systems.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202102990.

Dietary supplementation of butyrate can prevent diet-induced obesity through increasing mitochondrial function in mice, yet the up-stream signaling pathway remains elusive. In this study, weaned mice were divided into two groups, fed control (CON) and high-fat diet (HF, 45% energy from fat), respectively, for 8 weeks. HFinduced obese mice, maintained on HF diet, were then divided into two groups; HFB group was gavaged with 80 mg sodium butyrate (SB) per mice every other day for 10 days, while the HF group received vehicle. It was shown that five gavage doses of SB significantly alleviated HF diet-induced obesity and restored plasma glucose, insulin and leptin to control levels. Muscle contents of ADP and AMP were significantly increased, which was associated with enhanced mitochondrial oxidative phosphorylation and up-regulated expression of fatty acid oxidation enzymes and uncoupling proteins, UCP2 and UCP3 in the skeletal muscle. SB significantly enhanced the expression of adiponectin receptors (adipoR1/2) and AMP kinase (AMPK), while diminished the expression of histone deacetylase 1 (HDAC1). Higher H3K9Ac, a gene activation histone mark, was detected on the promoter of Adipor1/2, Ucp2 and Ucp3 genes that were activated in the muscle of SB-treated obese mice. Our results indicate that short-term oral administration of SB can alleviate diet-induced obesity and insulin resistance in mice through activation of adiponectin-mediated pathway and stimulation of mitochondrial function in the skeletal muscle.

Glucose-6-phosphatase (G6PC) plays an important role in glucose homeostasis because it catalyzes the final steps of gluconeogenesis and glycogenolysis. Maternal malnutrition during pregnancy affects G6PC activity, yet it is unknown whether epigenetic regulations of the G6PC gene are also affected. In this study, we fed primiparous, purebred Meishan sows either standard-protein (SP; 12% crude protein) or low-protein (LP; 6% crude protein) diets throughout gestation and analyzed hepatic G6PC expression in both male and female newborn piglets. The epigenetic regulation of G6PC, including DNA methylation, histone modifications, and micro RNA (miRNA), was determined to reveal potential mechanisms. Male, but not female, LP piglets had a significantly lower serum glucose concentration and greater hepatic G6PC mRNA expression and enzyme activity. Also, in LP males, glucocorticoid receptor binding to the G6PC promoter was lower compared with SP males, which was accompanied by hypomethylation of the G6PC promoter. Modifications in histones also were gender dependent; LP males had less histone H3 and histone H3 lysine 9 trimethylation and more histone H3 acetylation and histone H3 lysine 4 trimethylation on the G6PC promoter compared with the SP males, whereas LP females had more H3 and greater H3 methylation compared with their SP counterparts. Moreover, two miRNA, ssc-miR-339-5p and ssc-miR-532-3p, targeting the G6PC 3' untranslated region were significantly upregulated by the LP diet only in females. These results suggest that a maternal LP diet during pregnancy causes hepatic activation of G6PC gene expression in male piglets, which possibly contributes to adult-onset hyperglycemia.

Obesity is a worldwide epidemic, and a risk factor for cardiovascular disease and type 2 diabetes. Consequently, the development of safe and effective anti-obesity drugs is an area of ongoing clinical interest. MicroRNAs play a vital role in anti-obesity by inhibiting the expression of genes involved in adipogenesis and lipogenesis. However, the clinical application of miRNAs has been limited by a lack of appropriate delivery systems. The discovery of microvesicles (MVs) has shed new light on the search for more efficient drug transport tools. In a previous study, we demonstrated that miRNA-130b suppressed fat deposition by inhibiting PPAR-g expression. In order to demonstrate whether miRNA-130b can be packaged into MVs and function as an endogenous form of miRNA-130b in recipient cells, we transfected HeLa-229 cells with plasmid to overexpress miRNA-130b. This enabled HeLa-229 cells to selectively package miRNA-130b into MVs and actively secrete the miRNA-130b enriched MVs into the culture media. We further verified that MVs enriched with miRNA-130b contain elevated concentrations of Argonaute 2 and heat shock protein 90a which are known to protect the circulating miRNAs from degradation. Exposure of primary cultured porcine adipocytes to purified, miRNA-130b-enriched MVs resulted in a significant down-regulation of PPAR-g expression which was associated with reduced adipogenesis and lipogenesis. Taken together, our results suggest that MVs may provide an effective transport systems for the deliver of miRNAs for therapeutic use. We also showed that MV-shuttled miRNA-130b inhibited adipogenesis and lipogenesis, and reduced fat deposition in recipient adipocytes by targeting PPAR-g.

Highly flexible PEDOT-based electronic textiles were successfully fabricated for wearable thermoelectric generators and strain sensors with high sensitivity and superior water durability.

Conducting polymer-based composite aerogel film is desired to be used as thermoelectric (TE) materials due to its good flexibility and ultralow thermal conductivity. Here, we proposed the simple freeze drying method to fabricate freestanding poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS)-based aerogel films without any crosslinker addition. The evolutions of morphology and TE performance were systemically investigated with various organic solvent addition. Furthermore, a series of the PEDOT:PSS/tellurium nanowires (Te-NWs) composite aerogel films was prepared, and the relationship between the structure and the charge-transport mechanism of the binary complex system was explored based on series and parallel models. Finally, an efficient dimethyl sulfoxide-vapor annealing was employed to further optimize the TE performance of PEDOT:PSS/ Te-NWs composite aerogel films. The ZT value was estimated to be 2.0 × 10 −2 at room temperature. On the basis of the flexibility and highly enhanced TE performance, a prototype TE generator consisting of p-type PEDOT:PSS/Te-NWs aerogel films and n-type carbon nanotube fibers as legs has been fabricated with an acceptable output power of 1.28 μW at a temperature gradient of 60 K, which could be potentially applied in wearable electronics.

The requirement of a portable electron is functioning as a driving force for a wearable energy instrument. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), as one of the most promising organic electron materials, has been widely studied in energy conversion devices. However, the efforts for PEDOT:PSS fibers are insufficient to boost the development of wearable thermoelectric energy harvesting. Here, a highly conductive p-type PEDOT:PSS fiber was produced by gelation process, which was 3 orders of magnitude higher than that of previous hydrogel fibers. Surprisingly, a posttreatment with organic solvents such as ethylene glycol and dimethyl sulfoxide tripled their electrical conductivity with an only 5% decreased Seebeck coefficient, consequently leading to an optimized thermoelectric power factor. Furthermore, we assembled a p−n-type thermoelectric device connecting five pairs of p-type PEDOT:PSS fibers and n-type carbon nanotube fibers. This fiber-based device displayed an acceptable output voltage of 20.7 mV and a power density of 481.2 μW•cm −2 with a temperature difference of ∼60 K, which might pave the way for the development of organic thermoelectric fibers for wearable energy harvesting.

To elucidate the effects of maternal dietary betaine supplementation on hepatic expression of cholesterol metabolic genes in newborn piglets and the involved epigenetic mechanisms, we fed gestational sows with control or betaine-supplemented diets (3 g/kg) throughout pregnancy. Neonatal piglets born to betaine-supplemented sows had higher serum methionine concentration and hepatic content of betaine, which was associated with significantly up-regulated hepatic expression of glycine N-methyltransferase. Prenatal betaine exposure increased hepatic cholesterol content and modified the hepatic expression of cholesterol metabolic genes in neonatal piglets. Sterol regulatory elementbinding protein 2 was down-regulated at both mRNA and protein levels, while 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR) was down-regulated at the mRNA level, but up-regulated at the protein level, in betaine-exposed piglets. The transcriptional repression of HMGCR was associated with CpG island hypermethylation and higher repressive histone mark H3K27me3 (histone H3 lysine 27 trimethylation) on the promoter, whereas increased HMGCR protein content was associated with significantly decreased expression of miR-497. Furthermore, LDL receptor was significantly down-regulated at both mRNA and protein levels in the liver of betaine-exposed piglets, which was associated with promoter CpG hypermethylation. In addition, the expression of cholesterol-27a-hydroxylase (CYP27a1) was up-regulated at both mRNA and protein levels, while the expression of cholesterol-7a-hydroxylase (CYP7a1) was increased at the mRNA level, but unchanged at the protein level associated with increased expression of miR-181. These results indicate that maternal betaine supplementation increases hepatic cholesterol content in neonatal piglets through epigenetic regulations of cholesterol metabolic genes, which involve alterations in DNA and histone methylation and in the expression of microRNA targeting these genes.Key words: Betaine: Epigenetic regulation: Cholesterol metabolism: Maternal diet: PigletsCholesterol is an essential component of cell membranes and also serves as a precursor for life-sustaining steroid hormones and bile acids (1) . It is well known that deregulation of cholesterol metabolism contributes to obesity, diabetes and CVD (2,3) . Moreover, cholesterol is particularly essential for embryogenesis (4,5) , and low plasma cholesterol level is usually correlated with low body weight at birth (6 -8) .Hepatic cholesterol homeostasis is maintained through the coordinated regulation of three relevant processes: biosynthesis; transportation; transformation (4,9) . In particular, sterol regulatory element-binding protein-2 (SREBP2) (10) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) (11) are key factors/enzymes for cholesterol biosynthesis, LDL receptor (LDLR) and HDL receptor (scavenger receptor class B type I (SR-BI)) are responsible for transportation (12) , while cholesterol-7a-hydroxylase (CYP7a1) and cholesterol-27a-hydroxylase (CYP27a1) (13...