Nanoscale mapping of refractive index by using scattering-type scanning near-field optical microscopy

We present a novel method for nanoscale reconstruction of complex refractive index by using scattering-type Scanning Near-field Optical Microscopy (s-SNOM). Our method relies on correlating s-SNOM experimental image data with computational data obtained through simulation of the classical oscillating point-dipole model. This results in assigning a certain dielectric function for every pixel of the s-SNOM images, which further results in nanoscale mapping of the refractive index. This method is employed on human erythrocytes to demonstrate the approach in a biologically relevant manner. The presented results advance the current knowledge on the capabilities of s-SNOM to extract quantitative information with nanoscale resolution from optical data sets with biological application.     

Individual and county level predictors of asthma related emergency department visits among children on Medicaid: A multilevel approach

Objective: Disparities in asthma outcomes are well documented in the United States. Interventions to promote equity in asthma outcomes could target factors at the individual and community levels. The objective of this analysis was to understand the effect of individual (race, gender, age, and preventive inhaler use) and county-level factors (demographic, socioeconomic, health care, air-quality) on asthma emergency department (ED) visits among Medicaid-enrolled children. This was a retrospective cohort study of Medicaid-enrolled children with asthma in 29 states in 2009. Multilevel regression models of asthma ED visits were constructed utilizing individual-level variables (race, gender, age, and preventive inhaler use) from the Medicaid enrollment file and county-level variables reflecting population and health system characteristics from the Area Resource File (ARF). County-level measures of air quality were obtained from Environmental Protection Agency (EPA) data. Results: The primary modifiable risk factor at the individual level was found to be the ratio of long-term controller medications to total asthma medications. County-level factors accounted for roughly 6% of the variance in the asthma ED visit risk. Increasing county-level racial segregation (OR=1.04, 95% CI=1.01-1.08) was associated with increasing risk of asthma ED visits. Greater supply of pulmonary physicians at the county level (OR=0.81, 95% CI=0.68-0.97) was associated with a reduction in risk of asthma ED visits. Conclusions: At the patient care level, proper use of controller medications is the factor most amenable to intervention. There is also a societal imperative to address negative social determinants, such as residential segregation.     

The King laryngeal tube: a mimic of esophageal intubation in the emergency department

The King Airway is a temporary airway device used primarily in the pre-hospital setting and typically exchanged for an endotracheal tube upon arrival to the emergency department. Since this usually occurs before imaging, many radiologists are unfamiliar with the King Airway. This lack of familiarity can have important consequences for the patient and treating team. The purpose of this article is to raise awareness of the King Airway among radiologists, emphasize appropriate positioning, and review the imaging complications of incorrect positioning.