The plasma membrane is a highly compartmentalized, dynamic material and this organization is essential for a wide variety of cellular processes. Nanoscale domains allow proteins to organize for cell signaling, endo- and exocytosis, and other essential processes. Even in the absence of proteins, lipids have the ability to organize into domains as a result of a variety of chemical and physical interactions. One feature of membranes that affects lipid domain formation is membrane curvature. To directly test the role of curvature in lipid sorting, we measured the accumulation of two similar lipids, 1,2-Dihexadecanoyl-sn-glycero-3-phosphoethanolamine (DHPE) and hexadecanoic acid (HDA), using a supported lipid bilayer that was assembled over a nanopatterned surface to obtain regions of membrane curvature. Both lipids studied contain 16 carbon, saturated tails and a head group tag for fluorescence microscopy measurements. The accumulation of lipids at curvatures ranging from 28 nm to 55 nm radii was measured and fluorescein labeled DHPE accumulated more than fluorescein labeled HDA at regions of membrane curvature. We then tested whether single biotinylated DHPE molecules sense curvature using single particle tracking methods. Similar to groups of fluorescein labeled DHPE accumulating at curvature, the dynamics of single molecules of biotinylated DHPE was also affected by membrane curvature and highly confined motion was observed.

Purpose Although medical students will influence the future U.S. health care system, their opinions on the Patient Protection and Affordable Care Act (ACA) have not been assessed since the 2016 presidential election and elimination of key ACA provisions. Understanding medical students’ views on health care policy and professional obligations can provide insight into issues that will be shaped by the next generation of physicians. Method From October 2017 to November 2017, the authors conducted an electronic survey of medical students from seven U.S. institutions to elicit opinions regarding the ACA and their professional responsibility to address health policy. Participant demographics and responses were tabulated, and multiple logistic regression models were used to assess the associations of demographic characteristics with student opinions. Results Completed surveys were returned by 1,660/4,503 (36.9%) eligible medical students. Respondent demographics were similar to national estimates. In total, 89.1% (1,475/1,660) supported the ACA, and 82.0% (1,362/1,660) reported that they understood the health care law. Knowledge of the law’s provisions was positively associated with support for the ACA (P < .001). Most students (85.8%; 1,423/1,660) reported addressing health policy to be a professional responsibility. Political affiliation was consistently associated with student opinions. Conclusions Most medical students support the ACA, with greater levels of support among medical students who demonstrated higher levels of objective knowledge about the law. Furthermore, students indicated a professional responsibility to engage in health policy, suggesting that tomorrow’s physicians are likely to participate in future health care reform efforts.