A hybrid electrochemical/chemical (E/C) synthesis of zinc oxide (ZnO) nanoparticles and films is described. The E/C procedure involves two steps:  Zinc metal was first electrochemically deposited at basal-plane oriented graphite electrode surfaces from dilute aqueous solutions; then this deposit was permitted to spontaneously oxidize and dehydrate at open circuit in the pH = 1.0 plating solution. Deposition was size-selective, and wurtzite phase ZnO nanocrystallites having mean diameters in the range from 15 to 100 Å were obtained using this approach. Relative standard deviations of the particle diameter for ZnO particle dispersions varied from 25 to 50%. Polycrystalline ZnO films of 100−400 Å in thickness were also obtained by depositing larger quantities of zinc metal in the first step of the synthesis. For ZnO particles (dia. < 80 Å), electron diffraction analysis revealed a preferred orientation for ZnO crystallites where the c-axis of the wurtzite unit cell was oriented perpendicular to the plane of the graphite surface, but X-ray powder diffraction data indicated that this orientational preference was lost when larger quantities of zinc were deposited and ZnO films were obtained. Luminescence spectra for the ZnO films prepared using this E/C method consisted of a single exciton band near 3.2 eV at room temperature with no deep trap state emission. At low temperatures (20 K), this exciton band split into a cleanly resolved and fully assignable phonon loss progression.

Silver nanoparticles having a mean height ranging from 2 to 20 nm have been electrodeposited on hydrogen-terminated n2+-Si(100) surfaces. The deposition of silver was carried out potentiostatically from dilute ([Ag+] = 1 mM) acetonitrile-based solutions using a large overpotential, E appl = −800 mV versus Ag+/Ag0, and a voltage pulse duration ranging from 2 to 25 ms. Under these conditions, less than 0.20 of a silver monolayer was deposited, and this silver was present on the surface as silver nanoparticles which were similar in size. The metallic nature of these nanoparticles was confirmed using selected area electron diffraction. The evolution of the areal density of nanoparticles, and the nanoparticle height were both tracked as a function of the plating pulse duration ex situ using noncontact atomic force microscopy. As the pulse duration was increased from 2 to 25 ms, the mean nanoparticle height increased from 2 to 20 nm while the areal density of nanoparticles concurrently increased from 1 to 3 × 108 cm-2 to 2−2.5 × 109 cm-2. This result shows conclusively that the nucleation of silver on Si(100) is progressive in this time domain.

Many hospitals wish to improve their patients’ experience of care. In order to learn whether social media could be used as a tool to engage patients and to identify opportunities for hospital quality improvement (QI), we solicited patients’ narrative feedback on the Baystate Medical Center (BMC) Facebook page during a three-week period in 2014. Two investigators used directed qualitative content analysis to code comments and descriptive statistics to assess the frequency of selected codes and themes. We identified common themes, including: 1.) comments about staff (17/37 respondents, 45.9%); 2.) comments about specific departments (22/37, 59.5%); 3.) comments on technical aspects of care, including perceived errors and inattention to pain control (9/37, 24.3%); and 4.) comments describing the hospital physical plant, parking, and amenities (9/37, 24.3%). A small number (n=3) of patients repeatedly responded, accounting for 30% (45/148) of narratives. While patient feedback on social media could help to drive hospital QI efforts, any potential benefits must be weighed against the reputational risks, the lack of representativeness among respondents, and the volume of responses needed to identify areas of improvement.