Self-assembled periodical polycrystalline-ZnO/a-C nanolayers on Zn nanowire.

Zn nanowires with an epitaxial thin surface layer of zinc oxide were dispersed onto amorphous carbon films and stored at room temperature. After 1500 h, a self-organized equal-spaced zinc oxide (approximately 2 nm)/carbon (approximately 2.5 nm) multilayer structure was found to form outside the Zn nanowire, taking the place of the original ZnO surface layer. We carried a systematic study to clarify the self-formation mechanism of the periodical multilayers outside the Zn nanowire and found out that such a configuration originated from a chemical reaction between Zn and CO2 and were formed via a gas phase diffusion-interfacial chemical reaction-phase separation process.

Ultrafast MR imaging of water mobility: animal models of altered cerebral perfusion.

"Single shot" magnetic resonance (MR) diffusion imaging was used to study the details of signal decay curves in experimental perturbations of cerebral perfusion induced by hypercapnia or death. Despite large perfusion increases observed with dynamic susceptibility-contrast MR imaging, no correlation with these changes was seen in either the diffusion coefficient or any other intravoxel incoherent motion (IVIM) model parameters in dog gray matter as arterial carbon dioxide pressure increased. Non-monoexponential signal decay in cat gray matter was seen both before and after death. In addition, cat gray matter demonstrated a steady decrease in the diffusion coefficient after death. These data are strong evidence that the fast component of the non-monoexponential diffusion-related signal decay is not due solely to perfusion. The authors believe that a second compartment of nonexchanging spins, most likely cerebrospinal fluid, accounts for the non-monoexponential decay.

Dilute iron dextran formulation for addition to parenteral nutrient solutions.

The stability of dilute iron dextran formulations and of one formulation in parenteral nutrient solutions was studied. Seven formulations for dilute (50 mg/dl) iron dextran solutions and four parenteral nutrient solutions containing 100 mg/liter of iron dextran were prepared. Total iron and free ferrous ion content of the preparations were measured for: (1) the dilute solutions at monthly intervals after up to three months of storage at room temperature and under refrigeration and (2) the parenteral nutrient solutions after 18 hours of storage at room temperature. Four of the seven dilute solutions were stable after two months of storage. The easiest-to-prepare dilute solution (iron dextran, benzyl alcohol, and sterile water for injection) was stable for three months; stability was greater when refrigerated. Iron dextran was stable in the four parenteral nutrient solutions after 18 hours of room-temperature storage. The study suggests that addition of recommended daily doses of iron dextran to parenteral nutrient solutions creates no stability problems; however, further study of the effects of temperature, pH, light, and storage time are recommended.