Effect of Redox Atmosphere on Contact Electrification of Polymers.

The Triboelectric Nanogenerator has demonstrated broad applications in energy, environmental, and electronic fields, as well as huge potential in the mechanism study of contact electrification, since 2012. Herein, we employed a Triboelectric Nanogenerator working in vertical contact-separation mode to study the electrification performance of the polymer under redox atmosphere. The results show that the electron-withdrawing ability of the polymer is weakened with increasing O3 concentration. Considering that O3 is typically one of the strongest oxidants, we further studied the electrification performance under H2, CO, and O2 atmosphere. It is found that the electron-withdrawing ability was predictably weakened under O2 atmosphere similar to the case of O3. On the contrary, the electron-withdrawing ability was enhanced under H2 and CO atmosphere. Accordingly, a theoretical mechanism involving the highest occupied surface state level is proposed to explain the effect of redox atmosphere on contact electrification. These results clarify that contact electrification can be varied by redox agents. Conversely, it also suggests the possibility to manipulate the redox reactions through the modification of contact electrification.

Bipolar charge transfer induced by water: experimental and first-principles studies.

The mechanism underlying bipolar charge distribution in the context of triboelectrification remains ambiguous. Furthermore, water can either promote or inhibit triboelectrification. It was determined through experimental and first-principles calculations that water can also reverse the polarity of transferred charges and cause a bipolar charge transfer. We examined triboelectrification between an Au/Cr-coated tip and stoichiometric Si3N2 film using Kelvin probe force microscopy. In addition, we investigated the generation of a bipolar charge distribution on the insulating Si3N2 surface by controlling the frictional conditions. With regard to the effect of a water meniscus in the interface between the surface and tip, we predicted the dissociation of water molecules on the Si3N2 surface and polarity reversing induced by water via first principles. Finally, we focused on the effect of water on the dangling bonds of Si atoms and surface states of Si3N2. The results indicated that the dangling bonds and surface states are essential to a bipolar charge transfer.

A prospective, randomized, controlled study of a suspension positioning system used with elderly bedridden patients with neurogenic fecal incontinence.

Elderly patients with acute neurological impairment are prone to severe disability, fecal incontinence (FI), and resultant complications. A suspension positioning system (SPS), based on the orthopedic suspension traction system commonly used for conservative treatment of pediatric femoral fracture and uncomplicated adult pelvic fracture, was developed to facilitate FI management in patients immobilized secondary to an acute neurological condition. To evaluate the effectiveness and safety of the system, a prospective, randomized, controlled study was conducted between October 2009 and July 2012. Two hundred (200) elderly, bedridden, hospitalized patients with acute, nonchronic neurological impairment were randomly assigned to receive routine FI nursing care (ie, individualized dietary modification, psychological support, health education, and social support for caregivers and family members [control group]) or routine incontinence care plus the SPS (experimental group) during the day. Rates of perianal fecal contamination, skin breakdown, incontinence associated dermatitis, pressure ulcer development, and lower urinary tract infection (LUTI) were significantly lower in the SPS than in the control group (P <0.05). Length of hospitalization and costs of care were also lower in the SPS group (P <0.05). Patient quality-of-life (QoL) and FI QoL scores were similar at baseline but significantly higher (better) at the 6-month follow-up interview in the SPS than in the control group (P <0.05). In this study, the rate of FI-associated morbidities was lower and 6-month patient QoL scores were higher in the SPS than in the control group. No adverse events were observed, and all patients completed the study. Further clinical studies are needed to examine the long-term effects of SPS use among neurologically impaired FI patients.

[Fifty years of medical education of Hainan Province].

The 50 years' history of medical education of Hainan Province in new China was investigated in the study. The developmental histories of Hainan College of Medicine and Hainan Secondary Health School were stated, dealing with the enhancement of the cultivation of health professionals to provide public health service and the great improvement of the condition of lacking doctor and medicine in hinterland area of the province.