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Surface energy plays an important role in surface physics, [1,2] biophysics, [3,4] surface chemistry, [5,6] and catalysis. [7] A gradient of surface energy between a solid and liquid interface can induce transport of liquids [8][9][10][11] and water running uphill, [12] which is important for DNA analysis devices.[13] Due to the 2D nature and relatively few molecules or atoms involved, the density of surface energy is usually quite small, which is impractical for utilizing surface energy as an energy source. Nevertheless it is attractive to use surface energy at the nanoscale because of the lower power consumption for nanodevices and the higher specific surface area for nanomaterials. [14][15][16][17][18] In this work, we demonstrate an effective design of single-walled carbon nanotubes (SWNTs) to harvest surface energy of ethanol and convert it into electricity. In this ethanol-burner-like design, an open-circuit voltage (V oc ) can be obtained as a result of ethanol flow in the capillary channels formed among SWNTs driven by surface tension. The V oc remains constant as long as there is ethanol from the source. The maximum power can be up to $1770 pW per device and can serve as a self-powered system to drive a thermistor. Meanwhile, the performance (the inducing rate of V oc , the value of V oc , and the output power) can be significantly enhanced by the Marangoni effect. [19] SWNTs were synthesized by floating catalytic chemical vapor deposition and treated by diamond wire drawing dies, [20][21][22] which results in well-aligned individual SWNTs (see Supporting Information S1). The resulting SWNT rope ($25.0 mm (length) Â 0.6 mm (diameter), Fig. 1a) is connected to electrodes of aluminum film, forming a suspended structure on a glass slide. The device is measured by a Keithley 4200-SCS, semiconductor characterization system, (voltage resolution 1 mV) and the dynamic characteristics of the open-circuit voltage (V oc ) are monitored while adding ethanol (MOS grade, 99.9%) to the beaker (Fig. 1b, see Supporting Information S2).In an open beaker, no obvious V oc is observed at the beginning (angle 408, Fig. 2a). When the ethanol level reaches the SWNT rope, the V oc begins to increase. The increase of V oc is almost linear from zero to 200 mV for the first 240 s, then the V oc saturates gradually at 219 mV where is remains constant over 6 h as shown in Figure 2a. V oc can remain constant as long as the ethanol level is contacting the SWNT rope. When the beaker is covered as indicated by region 2 (Fig. 2b), V oc will gradually decrease back to the original value. This process can be repeated COMMUNICATION www.MaterialsViews.com www.advmat.de Figure 1. The SWNT device and schematic layout of the experimental setup. a) An image of the device with a suspended SWNT rope. After treating with diamond wire drawing dies, the SWNT rope has a diameter of $0.6 mm and length of $25.0 mm and is connected to the electrodes. b) When measuring, the device is placed into a beaker with an angle between the SWNT rope and the ethanol ...

Vascular endothelial dysfunction is an early marker of atherosclerosis seen in type 2 diabetes (T2DM). Circulating endothelial progenitor cell (EPC) is involved in the neovasculogenesis and maintenance of vascular homeostasis, whose impairment may have an important role in the pathogenesis of diabetic vasculopathy. This study was performed to investigate the relationship between vascular endothelial function and circulating EPC number in T2DM. A total of 46 newly diagnosed T2DM patients (DM group) and 51 healthy subjects (NG group) were recruited. Metformin was administered to all patients for 16 weeks. Endothelial function was assessed by flow-mediated brachial artery dilatation (FMD). EPC was defined by CD45( low)/CD34(+)/VEGFR2(+) and quantified by flow cytometry. The EPC number in the DM group was significantly lower than that in the NG group (p < 0.001), and improved markedly after treatment (p < 0.001). The results of FMD were consistent with EPC variations among the three groups (p < 0.001). In multivariate regression analysis, the EPC number was an independent risk factor for FMD at baseline (p < 0.05). The absolute changes of EPC number showed significant correlation with the changes of FMD before and after treatment (r = 0.63, p < 0.001). This study demonstrated that the circulating EPC number was related to endothelial function and could be considered as a surrogate biological marker of endothelial function for T2DM.