**Acknowledgements**

This publication resulted in part from research support from the National Science Foundation [NSF IOS-1355034], Howard University College of Medicine and the District of Columbia Center for AIDS Research, an NIH-funded program [P30AI117970], which is supported by the following NIH co-funding and participating institutes and centers: NIAID, NCI, NICHD, NHLBI, NIDA, NIMH, NIA, NIDDK, NIMHD, NIDCR, NINR, FIC, and OAR. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
