Converting body heat into electricity is a promising strategy for supplying power to wearable electronics. To avoid the limitations of traditional solid-state thermoelectric materials, such as frangibility and complex fabrication processes, we fabricated two types of thermogalvanic gel electrolytes with positive and negative thermo-electrochemical Seebeck coefficients, respectively, which correspond to the n-type and p-type elements of a conventional thermoelectric generator. Such gel electrolytes exhibit not only moderate thermoelectric performance but also good mechanical properties. Based on these electrolytes, a flexible and wearable thermocell was designed with an output voltage approaching 1 V by utilizing body heat. This work may offer a new train of thought for the development of self-powered wearable systems by harvesting low-grade body heat.

Sustainable electrical potential of tens of millivolts can be induced by water vapor adsorption on a piece of porous carbon film that has two sides with different functional group contents. Integrated experiments, and Monte Carlo and ab initio molecular dynamics simulations reveal that the induced potential originates from the nonhomogeneous distribution of functional groups along the film, especially carboxy groups. Sufficient adsorbed water molecules in porous carbon facilitate the release of protons from the carboxy groups, resulting in a potential drop across the carbon film because of the concentration difference of the released free protons on the two sides. The potential utilization of such a phenomenon is also demonstrated by a self-powered humidity sensor.

Converting body heat into electricity is a promising strategy for supplying power to wearable electronics. To avoid the limitations of traditional solid-state thermoelectric materials, such as frangibility and complex fabrication processes, we fabricated two types of thermogalvanic gel electrolytes with positive and negative thermo-electrochemical Seebeck coefficients, respectively, which correspond to the n-type and p-type elements of a conventional thermoelectric generator. Such gel electrolytes exhibit not only moderate thermoelectric performance but also good mechanical properties. Based on these electrolytes, a flexible and wearable thermocell was designed with an output voltage approaching 1 V by utilizing body heat. This work may offer a new train of thought for the development of self-powered wearable systems by harvesting lowgrade body heat.Given the recent developments in the area of wearable electronics and e-skins, [1][2][3][4][5][6] the emerging need for selfpowered energy supply has heightened the interest in energy harvesting from the environment or human beings. Among recognized energy-harvesting technologies, such as solar cells [7,8] and triboelectric and electret generators, [9,10] thermal energy is a potential power source that is widely available in the environment and in industrial processes. [11,12] However, human bodies are also a permanent heat source, with a surface temperature of about 32 8C and possibly tens of degrees temperature difference between the human body and its environment. [13,14] Hence, it is of practical meaning to convert body heat energy, a type of low-grade heat, into electricity for directly powering wearable electronics. [15][16][17] The most convenient strategy to utilize low-grade heat is thermal-electric conversion. Traditional thermoelectric generators utilizing the Seebeck effect are mainly based on solidstate semiconductors or conducting polymers, [18,19] with output voltages limited by the relatively low Seebeck coefficient (several hundreds mV K À1 ). Meanwhile, the frangibility and expensiveness of thermoelectric materials as well as their complicated fabrication processes are other obstacles restricting their application in wearable electronics. [20] Alternatively, a large thermovoltage can be derived from thermogalvanic effects, resulting from temperature-dependent entropy changes during electron transfer between redox couples and electrodes. [21][22][23][24] Previous reports mainly focused on the exploration of electrode materials, such as carbon nanotubes (CNTs) and graphene, [25][26][27][28] to achieve high thermal-electric conversion efficiencies. However, because of the aqueous electrolytes used in thermocells, large-scale integration and packaging of the units would be more difficult in applications, especially for wearable devices. [29] Inspired by the successful application of gel electrolytes in solid-state electrochemical energy storage systems and stretchable ionic conductors, [30][31][32][33] we surmised that solid-state or quasi-solidstate gel...

Adsorption-driven heat pumps (AHPs) based on metal–organic frameworks (MOFs) have been garnering rapidly growing research interests due to their outstanding adsorption performance.

BackgroundAcute diarrhea is a leading cause of morbidity and mortality in children, particularly in those under the age of 5 years. Rotavirus is recognized as the leading cause of acute diarrhea in children, however, the contribution of bacterial pathogens as causative agents varies throughout the world. Here we report a hospital-based prospective study to analyze the characteristics of bacterial pathogens associated with acute diarrhea in children under 5 years of age.MethodsStool samples were collected from 508 patients with acute diarrhea under 5 years of age who presented at our hospital. Nine pathogens were isolated and identified by culturing, serology or PCR, these included Salmonella spp., Shigella spp., Vibrio cholerae, diarrheagenic Escherichia coli (DEC), Aeromonas spp., Plesiomonas spp., Vibrio parahaemolyticus, Campylobacter spp. and Yersinia enterocolitica. Antimicrobial sensitivity tests of these pathogens were conducted. The most commonly detected pathogen, Salmonella spp., was further investigated by PCR and sequencing of antibiotic resistance-related genes.ResultsPathogens were identified in 20.1 % of the 508 samples. The most commonly detected pathogens were Salmonella spp. (8.5 %), followed by DEC (4.7 %), Campylobacter jejuni (3.0 %) and Aeromonas spp. (2.0 %). The resistance rates to ampicillin and tetracycline in Salmonella spp. were >60 %, but were <30 % to cephalosporins and quinolones. More than 50 % of DEC strains displayed resistance to ampicillin, cefotaxime and tetracycline, and 60 % of C. jejuni strains were resistant to ciprofloxacin but highly sensitive to the other antibiotics. Among 12 cephalosporin-resistant Salmonella isolates, TEM-1 and CTX-M-14 determinants were present in two (16.7 %) isolates. PCR screening for plasmid-mediated quinolone resistance genes revealed gyrA mutations in one of three highly quinolone resistant isolates.ConclusionsSalmonella spp., DEC, Campylobacter spp. and Aeromonas spp. were the most commonly detected bacterial pathogens in children under the age of 5 years with acute diarrhea. Our findings indicate that ampicillin and tetracycline are not suitable as first line therapeutic drugs against Salmonella spp. Resistance to third generation cephalosporins and quinolones was also detected. TEM-1 and CTX-M-14 genetic determinants, and gyrA mutations, were the major mechanisms associated with high levels of cephalosporin and quinolone resistance, respectively, in Salmonella isolates.

BackgroundAlthough the genetic cause for Huntington’s disease (HD) has been known for over 20 years, the mechanisms that cause the neurotoxicity and behavioral symptoms of this disease are not well understood. One hypothesis is that N-terminal fragments of the HTT protein are the causative agents in HD and that peptide sequences adjacent to the poly-glutamine (Q) repeats modify its toxicity. Here we test the function of the N-terminal 17 amino acids (N17) in the context of the exon 1 fragment of HTT in a novel, inducible zebrafish model of HD.ResultsDeletion of N17 coupled with 97Q expansion (mHTT-ΔN17-exon1) resulted in a robust, rapidly progressing movement deficit, while fish with intact N17 and 97Q expansion (mHTT-exon1) have more delayed-onset movement deficits with slower progression. The level of mHTT-ΔN17-exon1 protein was significantly higher than mHTT-exon1, although the mRNA level of each transgene was marginally different, suggesting that N17 may regulate HTT protein stability in vivo. In addition, cell lineage specific induction of the mHTT-ΔN17-exon1 transgene in neurons was sufficient to recapitulate the consequences of ubiquitous transgene expression. Within neurons, accelerated nuclear accumulation of the toxic HTT fragment was observed in mHTT-ΔN17-exon1 fish, demonstrating that N17 also plays an important role in sub-cellular localization in vivo.ConclusionsWe have developed a novel, inducible zebrafish model of HD. These animals exhibit a progressive movement deficit reminiscent of that seen in other animal models and human patients. Deletion of the N17 terminal amino acids of the huntingtin fragment results in an accelerated HD-like phenotype that may be due to enhanced protein stability and nuclear accumulation of HTT. These transgenic lines will provide a valuable new tool to study mechanisms of HD at the behavioral, cellular, and molecular levels. Future experiments will be focused on identifying genetic modifiers, mechanisms and therapeutics that alleviate polyQ aggregation in the nucleus of neurons.Electronic supplementary materialThe online version of this article (doi:10.1186/s13024-015-0063-2) contains supplementary material, which is available to authorized users.

The thermal conductivity of metal−organic frameworks (MOFs) imposes significant impacts on the thermal transfer performance of related adsorption systems in engineering applications. However, how the structural properties of MOFs affect their thermal conductivities has yet to be unraveled. In this work, the thermal conductivities of 18 zeolitic imidazolate frameworks (ZIFs) were calculated by equilibrium molecular dynamics (MD) simulations. It was revealed that the thermal conductivities of ZIFs were not directly correlated with the commonly investigated structural properties. Thus, two parameters including alignment tensor (A i ) and pathway factor (P f ) were proposed to quantitatively evaluate the orientation and distribution of heat transfer pathways within frameworks, which was demonstrated to correlate better with the thermal conductivities of ZIFs. This study provides new insights into the thermal transfer mechanism within framework-based nanoporous materials, which may also facilitate fundamental understanding and guide the rational design of porous crystals with the thermal conductivity of interest.

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