Photoregulated Supramolecular Polymerization through Halogen Bonding.

Supramolecular polymers are able to change their structure, morphology and function in response to external stimuli. However, controlling the independence of stimuli-responses in these systems is challenging. Herein, we exploit halogen bonding (XB) as a reversible network element to regulate the photoresponsive and adaptive behavior of supramolecular polymers.

Appropriateness of lumbar spine magnetic resonance imaging in Spain.

Objectives: To determine the minimum percentage of lumbar spine magnetic resonance imaging (LSMRI) which are inappropriately prescribed in routine practice.

Methods: LSMRI performed prospectively on 602 patients in 12 Radiology Services across 6 regions in Spain, were classified as "appropriate", "uncertain" or "inappropriate" based on the indication criteria established by the National Institute for Clinical Excellence, the American College of Physicians and Radiology, and current evidence-based clinical guidelines. Studies on patients reporting at least one "red flag" were classified as "appropriate".