Transmission electron microscopy studies of NaLaMgWO6: spontaneous formation of compositionally modulated stripes.

Transmission electron microscopy studies of the perovskite NaLaMgWO 6 reveal the formation of a complex, compositionally modulated structure. Annular dark field scanning transmission electron microscopy images and scanning transmission electron microscopy-electron energy-loss spectroscopy scans show that this modulation involves a repeating pattern of La-rich and La-poor stripes, each stripe 6 a p or approximately 24 A wide (where a p is the edge length of the simple cubic perovskite unit cell). High-resolution transmission electron microscopy images clearly show, and electron diffraction patterns confirm, a periodicity of 12 a p along either the [100] p or [010] p direction. Available evidence suggests a spontaneous separation into stripes that possess the nominal stoichiometry, NaLaMgWO 6, alternating with Na-poor/La-rich stripes that have a stoichiometry of (La x Na 1-3 x )LaMgWO 6. X-ray powder diffraction measurements are insensitive to this intricate structural complexity, which may be a more widespread feature of (A (+)Ln (3+))MM'O 6 perovskites than previously appreciated.

Clinical Trial of an Educational Program to Decrease Monitor Alarms in a Medical Intensive Care Unit.

Clinical research to identify effective interventions for decreasing nonactionable alarms has been limited. The objective of this study was to determine if a staff educational program on customizing alarm settings on bedside monitors decreased alarms in a medical intensive care unit (MICU). A preintervention, postintervention, nonequivalent group design was used to evaluate an educational program on alarm management in a convenience sample of MICU nurses. A 15-minute session was provided in a 1-week period. The outcome variable (number of alarms for low oxygen saturation via pulse oximetry [SpO2]) was determined from monitor log files adjusted by patient census. Data were collected for 15 days before and after the intervention. χ2 analysis was used, with P less than .05 considered significant. After 1 week of education, low SpO2 alarms decreased from 502 to 306 alarms per patient monitored per day, a 39% reduction (P < .001). Instructions for nurses in the medical intensive care unit on individualizing alarm settings to patients' clinical condition decreased common monitor alarms by 39%.