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Background Gastric electric stimulation (GES) at a high-frequency, low-energy setting is an option for treating refractory gastroparesis. The currently available commercial stimulator, the Enterra neurostimulator (Medtronic Inc, Minneapolis, MN), however, requires surgical implantation and is powered by a nonrechargeable battery. Objective To develop and test a miniature wireless GES device for endoscopic implantation in an experimental model. Design In-vivo gastric signals were recorded and measured in a nonsurvival swine model (n = 2; 110-lb animals). Intervention An endoscopically placed, wireless GES device was inserted into the stomach through an overtube; the two GES electrodes were endoscopically attached to the gastric mucosa and secured with endoclips to permit stimulation. Main Outcome Measurements Stable electrogastrogram measures were observed during GES stimulation. Results Electrogastrogram recordings demonstrated that gastric slow waves became more regular and of constant amplitudes when stomach tissues were stimulated, in comparison with no stimulation. The frequency-to-amplitude ratio also changed significantly with stimulation. Limitation Nonsurvival pig studies. Conclusion Gastric electric stimulation is feasible by our endoscopically implanted, wireless GES device.

An intuitive design strategy for organic semiconductors with ultrasmall reorganization energy (λ) is proposed. Learning from a total of 98 molecules condensed by benzene and/or thiophene rings, we find that linear compounds in D 2h symmetry have the smallest λ in each of the three molecular categories (PAHs, thienothiophenes, benzothiophenes). 2D expanded analogues that contain these D 2h building blocks also give unusually small λ (<100 meV). λ of 1D elongated polycyclics show an approximate linear correlation with the ring-averaged HOMA indices and the HOMO–LUMO gaps. Compared to the symmetry principle, the HOMA and energy gap, though much less intuitive to design a priori, provide additional quantitative guidelines to further optimize λ through substitutions, for example, when molecules have the same symmetries. Our results indicate that ring-fused π-conjugates that have narrower HOMO–LUMO gaps and are less aromatic are better candidates to achieve ultrasmall λ.

The effects of tin substitution on the phase formation, the Curie temperature, and the magnetic entropy change of the monoclinic Gd5Si1.95Ge2.05 alloy have been investigated. Five Sn-doped Gd5Si1.95−xGe2.05−xSn2x samples were prepared with 2x=0, 0.01, 0.03, 0.05, and 0.10, respectively. Experimental results show that a small amount of Sn doping in Gd5Si1.95Ge2.05 retains the first order structural/magnetic transition, significantly enhances its magnetocaloric effects as well as increase its Curie temperature Tc, but leads to increase in hysteresis loss due to its field-induced monoclinic to orthorhombic phase transformation. The maximum magnetic entropy change of the Sn-doped Gd5Si1.935Ge2.035Sn0.03 sample for the 0–2.0T magnetic field change reaches 28.9Jkg−1K−1 at 277K, which is twice as large as that of pure Gd5Si1.95Ge2.05 (14.1Jkg−1K−1 at 260K) for the same magnetic field change.

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Charge reorganization energies (λ) of inter-ring carbon–carbon (IRCC) bond connected conjugated polycyclics are shown to exhibit an electric-field-driven anisotropic character.

pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages in specific applications. It is difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to size limitation and no deformability. In this paper, we present design and fabrication processes of a miniature iridium oxide thin film pH sensor array on flexible polymer substrates. The amorphous iridium oxide thin film was used as the sensing material. A sol-gel dip-coating process of iridium oxide film was demonstrated in this paper. A super-Nernstian response has been measured on individual sensors of the array with a slope of-71.6 ± 3 mV/pH at 25 o C within the pH range between 2.83 and 11.04.

Background Gastric stimulation via high-frequency, low-energy pulses can provide an effective treatment for gastric dysmotility; however, the current commercially available device requires surgical implantation for long-term stimulation and is powered by a nonrechargeable battery. Objective To test and describe endoscopic implantation techniques and testing of stimulation of a novel, wireless, batteryless, gastric electrical stimulation (GES) device. Design Endoscopic gastric implantation techniques were implemented, and in vivo gastric signals were recorded and measured in a non-survival swine model (n = 2; 50-kg animals). Intervention Five novel endoscopic gastric implantation techniques and stimulation of a novel, wireless, batteryless, GES device were tested on a non-survival swine model. Main Outcome Measurements Feasibility of 5 new endoscopic gastric implantation techniques of the novel, miniature, batteryless, wireless GES device while recording and measurement of in vivo gastric signals. Results All 5 of the novel endoscopic techniques permitted insertion and securing of the miniaturized gastrostimulator. By the help of these methods and miniaturization of the gastrostimulator, successful GES could be provided without any surgery. The metallic clip attachment was restricted to the mucosal surface, whereas the prototype tacks, prototype spring coils, percutaneous endoscopic gastrostomy wires/T-tag fasteners, and submucosal pocket endoscopic implantation methods attach the stimulator near transmurally or transmurally to the stomach. They allow more secure device attachment with optimal stimulation depth. Limitations Non-survival pig studies. Conclusion These 5 techniques have the potential to augment the utility of GES as a treatment alternative, to provide an important prototype for other dysmotility treatment paradigms, and to yield insights for new technological interfaces between non-invasiveness and surgery.