Pulmonary & Critical Care Fellowship Programs

Current and Former Fellows

Sleep Medicine


“I attended undergraduate and medical school at University of Iowa, after initially being interested in a career as a saxophonist. I have been involved in research projects ranging from glioblastoma growth traits to lighting within a hospital system as a patient satisfaction metric. After finishing neurology residency at Northwestern, I am excited to attend University of Chicago for sleep medicine fellowship and, ultimately, a career as a sleep neurologist. I enjoy music, the Chicago Bulls, his dog, and…sleeping!.” 

Tony Rosenberg, MD

Pulmonary/Critical Care

Hi, I’m Nathan. I hail from the warm, sunny state of Florida. I attended medical school at Florida State University and completed my residency training at Baylor College of Medicine in Houston, Texas. After completing 3 years of Pulmonary-Critical fellowship at the University of Chicago, I am continuing my training at UChicago as a sleep fellow. I chose UChicago Sleep for our diverse patient population, supportive faculty, and immense academic resources. My current research interests include obesity hypoventilation syndrome and cardiometabolic outcomes of obstructive sleep apnea.

Outside of work you can find me listening to live music, travelling, or enjoying dinner at one of Chicago’s many exceptional restaurants. Our city has an overwhelming supply of things to do!

Nathan Nowalk, MD


“ My hometown is Troy, MI. I completed my Medical School at the Michigan State University College of Human Medicine. I completed a Neurology Residency at Ascension Macomb-Oakland Hospital. My favorite things to do in Chicago are exploring the city, eating at the diverse and vast number of restaurants, going on different city tours, visiting the museums, checking out various events and festivals.”

Gautam Ramesh, MD

Former Fellows


Year  Name  Hometown Residency/Fellowship Practice
2022 Gorav Sharma Battle Creek, Michigan

Residency: Internal Medicine, Mount Sinai Beth Israel, New York, NY


Fellowship: Pulmonary and Critical Care, Henry Ford Health System, Detroit, MI

Assistant Professor- The University of Chicago

Monica Singh

Farmington Hills, MI Family Medicine, West Virginia University Hospitalist-Sleep Private Practice

Nhi Lam

Dayton, OH Internal Medicine, Case Western Reserve University/ MetroHealth System Sleep Medicine – Cleveland VA, OH

Patricia Jimenez Guzman

El Salvador University of Illinois at Chicago (Pediatrics); University of Chicago (Sleep Medicine) Private Practive- Pediatric Sleep Medicine. Virginia

Aristotle Leonhard

Sheboygan, WI University of Chicago Medical Center- Internal Medicine Pulmonary & Critical Care Fellow. University of Washington. Seattle.

Kamonchanok (May) Jongyotha

Bangkok, Thailand

Residency: Internal Medicine at Weiss Memorial Hospital, Chicago

Fellowship: Geriatric Medicine fellowship at University of Pittsburgh Medical Center

Private Practice- Geriatrics & Sleep Medicine. South Dakota.
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