We investigated the efficiency of electrical power generation in single track-etched nanopores by measuring the streaming currents and conductance. Experimental results indicate that both the efficiency and output power depend on the electrolyte concentration and the dimension of the pore. The highest efficiency of 5% was obtained in nanopores with small radii of 31 nm. The surface property of the track-etched nanopores was found very important to the kinetic-electric behaviors in the pores, especially when the electrolyte concentration was low.
Synthetic conical nanochannels have gained attention for their ion rectification behavior, which can be used to mimic the functionalities of biological ion channels. Employing these nanochannels and inspired by biological synaptic dynamics, we herein demonstrate a new nanofluidic device as a memristor, the ion transport conductance of which depends on the history of its ion flow. The nanofluidic memristors show excellent repeatability, high ON/OFF ratios, and sufficiently long retention times, which are highly desirable for logic control and neuromorphic engineering applications in nanofluidic systems as well as for fundamental transport studies of ionic liquids on a nanoscale.
The strong demand for renewable energy promotes research on novel methods and technologies for energy conversion. Microfluidic systems for energy conversion by streaming current are less known to the public, and the relatively low efficiencies previously obtained seemed to limit the further applications of such systems. Here we report a microdropletbased electrostatic generator operating by an acceleration-deceleration cycle ('ballistic' conversion), and show that this principle enables both high efficiency and compact simple design. Water is accelerated by pumping it through a micropore to form a microjet breaking up into fast-moving charged droplets. Droplet kinetic energy is converted to electrical energy when the charged droplets decelerate in the electrical field that forms between membrane and target. We demonstrate conversion efficiencies of up to 48%, a power density of 160 kW m À 2 and both high-(20 kV) and low-(500 V) voltage operation. Besides offering striking new insights, the device potentially opens up new perspectives for low-cost and robust renewable energy conversion.
Purpose: Inactivation of p16 by aberrant methylation of CpG islands is a frequent event in carcinomas and precancerous lesions of various organs, including the stomach. The aim of this study is to investigate the relationship between p16 methylation and malignant transformation of human gastric dysplasia (DYS) based on follow-up endoscopic screening in a high-risk population.Experimental Design: Genomic DNA samples were extracted from paraffin blocks of gastric mucosal biopsies that were histopathologically diagnosed as low-grade DYS from patients who developed gastric carcinomas [GCs (n ؍ 21)] and those that did not do so (n ؍ 21) during 5 years of follow-up. The methylation status of p16 CpG islands of each sample was detected by methylation-specific PCR, denatured high-performance liquid chromatography, and sequencing.Results: Aberrant p16 methylation was observed in 5 of 21 samples of DYS that progressed to GC but in 0 of 21 samples that did not progress to GC (P ؍ 0.048, two-sided). Sequencing results confirmed that all CpG sites were methylated in the analyzed sequence from these five p16-methylated cases. Furthermore, p16 methylation was also observed in the five subsequent GCs. Unmethylated p16 CpG islands were detected in all of the samples without p16 methylation.Conclusions: Our findings suggest p16 methylation is correlated with the malignant transformation of gastric DYS, and p16 methylation might be a useful biomarker for prediction of malignant potential of gastric DYS.
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