Current Fellows
Pulmonary & Critical Care Fellows
Class of 2026-2029
Adolfo Diaz Barba, MD
Medical School: Universidad Nacional Autónoma de Nicaragua Facultad de Ciencias Médicas, Managua
Residency: University of Oklahoma
Bio: Adolfo was born in Matagalpa, Nicaragua, and completed medical school in Managua. Before joining Stanford, he completed residency at the University of Oklahoma in Oklahoma City. He is now excited to move to the Bay Area for PCCM training, and continue exploring his research interests in pulmonary complications of oncologic therapies and interstitial lung diseases. During his free time, he enjoys trying out new food trucks, playing table tennis, and watching his favorite soccer team play.
Rachel Dubner, MD
Medical School: New York University Grossman School of Medicine
Residency: Northwestern University
Bio: Rachel was born and raised in Pittsburgh, PA and went to college at Northwestern University. She moved to the east coast to attend medical school at NYU before returning to Chicago for residency and a chief year at Northwestern. She is thrilled to be moving to the Bay Area to join the Stanford PCCM community! In addition to her clinical work, she is passionate about medical education and simulation as a tool for teaching clinical reasoning and communication skills in high-acuity situations. Outside of the hospital, Rachel enjoys exploring new coffee and boba shops, spending time outdoors, and doing the NYT crossword.
Jackie Lin, MD
Medical School: UCSF
Residency: UCSF
Bio: Jackie was born in Dallas and grew up in Singapore, Hong Kong, and Beijing before moving to back to the States for college at Duke. She then ventured out to the West Coast and completed medical school and residency at UCSF. She is thrilled to stay in the Bay Area, which has become her home away from home, for PCCM fellowship at Stanford. She is interested in critical care medicine, and the application of informatic tools in clinical research and education. Outside of work, she enjoys picnics with her husband and daughter, long walks, and sewing.
Carson Moss, MD
Medical School: Harvard Medical School
Residency: Stanford University
Bio: Carson grew up in Sacramento, California and attended college nearby at UC Davis. After completing medical school at Harvard, he returned to California for Internal Medicine residency at Stanford, where he remained for PCCM fellowship. While at Stanford, he developed a clinical and research interest in the pulmonary complications of immune dysregulation, including chronic graft-versus-host disease, bronchiectasis, and opportunistic infections of the lung. Outside of the hospital, Carson enjoys running and tending to his ever-growing collection of plants.
Deepthi Nacharaju, MD
Medical School: Oregon Health & Science University School of Medicine
Residency: University of Washington
Bio: Deepthi grew up in Columbus, OH before attending Duke University and studying to become a semi-professional college basketball fan and biomedical engineer. She then trained in Internal Medicine at the University of Washington while hiking through the PNW with a camera or two strapped to her pack. She is excited to be a PCCM fellow at Stanford, where she can become an excellent clinician, continue her career as a research scientist, and start to explore subspecialties such as IP. After work, she's either hosting a dinner party for her friends and family or trying to find the best pizza in town, and is looking forward to running in the California sunshine.
Vanessa Nunez, MD
Medical School: UCLA
Residency: Brigham and Women's Hospital
Bio: Vanessa grew up in Dos Palos, California, and spent nearly a decade at UCLA, where she completed her undergraduate, medical, and business degrees before heading east for residency at Brigham and Women’s Hospital. She is thrilled to be back in California as part of the Stanford PCCM community! She is passionate about improving healthcare delivery and developing collaborative, sustainable models to expand access to high-quality care in under-resourced communities. Outside of medicine, she enjoys cooking, thrifting, and relaxing on warm beaches.
Faizah Shareef, MD
Medical School: Boston University School of Medicine
Residency: UCSD
Bio: Faizah was born in Brooklyn, New York and has bounced around the East Coast before finally making her way to California for internal medicine residency at UCSD. She is stoked to head to the Bay Area for PCCM at Stanford as her seventh city of residence in the U.S., where she hopes to explore her interests in medical innovation, global health, and health equity at a systems level. In her free time, she loves to be outdoors in all forms of nature, try new restaurants/bakeries, and enjoys belting 'A Whole New World' at karaoke.
Jonika Weerasekare, MD
Medical School: Mayo Clinic Alix School of Medicine
Residency: UC Davis
Bio: Jonika was born in Santa Cruz, CA and remained in California until moving to Minnesota for medical school. He returned to California for internal medicine residency at UC Davis. While at UC Davis, he developed interests in pulmonary hypertension, echocardiography, and shock. He is thrilled to join Stanford PCCM, particularly for the outstanding training in pulmonary hypertension. In his free time, Jonika enjoys spending time with his wife and their 2-year-old son.
Pulmonary & Critical Care Fellows
Class of 2025-2028
Shannen Kim, MD
Medical School: UCSF
Residency: UCSF
Bio: Shannen grew up in Chino Hills, California. She went to Harvard for college before coming to the Bay Area for medical school, where she has been ever since. After completing medical school and internal medicine residency at UCSF, she worked as a hospitalist at the San Francisco VA before starting fellowship. She is excited to be joining the Stanford PCCM community and looks forward to exploring her interests in critical care, end-of-life care and communication, and clinical design and innovation. Outside of medicine, she enjoys Tahitian dance, watching reality TV with her cat Sokka, and traveling abroad whenever she can!
Albert Ya-Po Lui, MD
Medical School: New York University
Residency: UCLA
Bio: Albert was born in Taipei, Taiwan and grew up between Taipei and Vancouver, BC. He moved to New York City for college at Columbia University, relocated west to California to pursue a master’s degree at Stanford University, and then returned to New York City for medical school at NYU. During his internal medicine residency training at UCLA, he developed interests in pulmonary hypertension, critical care, and machine learning applications within medicine. Outside of work, Albert enjoys watching horror movies, exploring local coffeeshops, training capoeira, and hiking through national parks.
John Rose, MD
Medical School: University of Virginia
Residency: University of Texas Southwestern
Bio: John was born and raised in Virginia, where he attended college and medical school. He made the trip westward to Dallas for residency at UT Southwestern. Following a chief resident year, he was thrilled to take the next step in his training as a PCCM fellow at Stanford in Sunny California. His academic and clinical interests include implementation science, pulmonary infections, and the care of veterans. Outside the hospital, he enjoys exploring art museums with friends, sampling new ice cream flavors, and the beach!
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‘Yoni’ Samuel Rubin, PhD, MD
Medical School: Stanford
Residency: Stanford
Bio: Yoni was raised in Seattle, WA and journeyed to California for college where he has meandered since. He is excited to continue training on The Farm as a PCCM fellow and to utilize his experience in immunology for research and clinical applications. Outside the hospital and laboratory, Yoni is an amateur runner as well as a semi-professional farm-to-table chef.
Adrienne Strait, MD
Medical School: UCSF
Residency: UCSF
Bio: Adrienne grew up in Oakland, CA. She attended Williams College in Massachusetts before returning to the Bay Area to complete medical school and residency at UCSF. She spent a year working as a hospitalist in San Francisco before beginning her fellowship at Stanford. Alongside her clinical work, she is passionate about medical education and improving patient safety through quality improvement initiatives. Outside of medicine, she enjoys running, hiking, spending time with friends and family, and baking.
Natalie Stumpf, MD
Medical School: Temple University
Residency: UCSF
Bio: Natalie was born in Oakland, California. She went to college in the Bay Area, moved to the East Coast for medical school at Temple University, then returned to the bay for internal medicine residency at UCSF. Her clinical interests include bronchiectasis and lung transplant. Outside of the hospital, she enjoys reading, knitting, and going on hikes with her dog.
Sangeetha Thevuthasan, MD
Medical School: University of Washington
Residency: Columbia
Bio: Sangeetha grew up in Eastern Washington. She went to college in Atlanta at Georgia Tech and moved back to Washington for medical school at the University of Washington. She ended up in New York City for internal medicine residency at Columbia and is thrilled to be moving back to her favorite coast for fellowship! Her clinical interests include critical care, interventional pulmonology and healthcare technology. Outside of work, she loves to spend time outside whether it’s running, playing basketball, or picnicking in parks.
Jonathan Tiao, MD
Medical School: Columbia
Residency: Columbia
Bio: Jonathan was born in Cincinnati, OH, and went to college at the University of Michigan before moving to the Bay Area for a brief 2 year stint in tech. Afterwards he moved to New York City for both medical school and residency before joining Stanford for fellowship. He is excited to explore his interests in critical care, technology innovation, and entrepreneurship. Outside of the hospital, he enjoys traveling, outdoor activities with his dog, and watching the Bengals/Wolverines.
Pulmonary & Critical Care Fellows
Class of 2024-2027
Tsion Abraham, MD
Medical School: George Washington University
Residency: UCSF
Bio: Tsion was born in Toronto, Ontario. She grew up in Canada until moving to DC to attend medical school at George Washington University. She made the move to the west coast for residency at UCSF and is excited to stay in the Bay Area for fellowship. Her clinical interests include critical care, pulmonary infections and interventional pulmonology. Outside of work, she enjoys running, spin classes and reading sci-fi novels.
Ben Berger, MD
Medical School: University of Utah
Residency: Duke
Bio: Ben grew up in Salt Lake City and went to the University of Utah for college and medical school. He left the mountains for residency at Duke. He is thrilled to return to the west for fellowship. Clinical interests include critical care, point-of-care ultrasound, and COPD. Academic interests include high-value healthcare, advocacy, and implementation science. Outside of work, he enjoys trail running, hiking, breweries, and hanging out with his fiancée and friends.
Chris Calkins, MD
Medical School: Stanford
Residency: Brigham & Women’s
Bio: Chris grew up in New England before making his first journey west for medical school at Stanford. After three years back in Boston for internal medicine residency at Brigham and Women's Hospital, Chris is thrilled to be back at Stanford for his fellowship training. Outside of clinical work, Chris is interested in medical education and quality improvement. When not in the hospital, Chris enjoys running, hiking, and exploring all California has to offer. Chris lives in Menlo Park with his wife, Madeline, and their cat, Piper.
Audrey Chai, MD
Medical School: USC/ Los Angeles General Hospital
Residency: USC/ Los Angeles General Hospital
Bio: Audrey was born and raised in Pasadena, California and is a true Southern California lifer. After finishing college at USC, she went on to complete medical school, internal medicine residency, and a chief residency year at USC/ Los Angeles General Hospital. During the PCCM fellowship interview process, she fell in love with the people and program at Stanford and is excited to come up to the Bay Area for this next chapter. In residency, she developed interests in medical education, rapid response and code blue training and lung cancer disparities. She hopes to work as a pulmonary and critical care clinician-educator after fellowship. Outside of medicine she enjoys spending time outdoors in sunny weather, Peloton-ing, and finding the best bakeries and dessert shops.
Sammy Emont, MD, MPH
Medical School: University of Miami
Residency: Columbia
Bio: Sammy was born in New York City and grew up in South Florida. She went to Yale for college but returned home where she attended University of Miami for medical school. She went back to New York to complete her residency at New York Presbyterian - Columbia and then spent a year working there as a hospitalist before making the big trip out to California to start fellowship at Stanford. Sammy is interested in ILD and lung transplant. Outside the hospital, she loves to run and play/watch tennis, hike with her dog, and visit vineyards.
Erica Mascarenhas, MD
Medical School: Tufts
Residency: Tulane
Bio: Erica was born and raised in Pennsylvania before heading to Boston for college and medical school. She left the East Coast and headed to New Orleans for her Internal Medicine residency at Tulane where she stayed on for an additional chief year during which she got to dance/march in several Mardi Gras parades. In the hospital, she's interested in medical education and health equity. Outside the hospital, she loves to run (with a recent interest in hiking now that she's in the mountains!), bake, listen to music and spend time with friends and family.
Arjun Panda, MD
Medical School: George Washington University
Residency: OHSU
Bio: Arjun was born in Cleveland Ohio, but considers the SF Bay Area his home - which is why after years away, he is thrilled to return for PCCM fellowship at Stanford to build a career helping people with respiratory diseases breathe more comfortably. In addition to his clinical work, he is passionate about clinical informatics, medical education in the ICU, and the history of medicine. When he's not in the hospital you can find him biking around town looking for his next oat-milk latte, or headphones in trying to perfect one of his seasonal Spotify playlists.
Abel Triana, MD, MSc
Medical School: Universidad del Norte, Colombia
Residency: University of Miami
Bio: Abel was born in Cartagena, Colombia, and completed medical training in Barranquilla. He gained research experience at a clinical trial center focused on diabetes and cardiovascular diseases. He then moved to Glasgow, Scotland, to pursue a master's degree in clinical trials and stratified medicine, with a research focus on sepsis and community-acquired pneumonia. During the COVID-19 pandemic, he returned to Colombia to work in the ER and ICU. Prior to joining Stanford, he was in Miami for residency. His professional interests include ILD, sleep medicine, and interventional pulmonology. In his free time, he enjoys traveling with his wife, spending time with friends, and playing soccer.
Pulmonary & Critical Care Fellows
T32 Research Fellow
Joseph Rathkey, MD
Medical School: Case Western Reserve University
Residency: Stanford
Bio: Joseph enjoys research (innate immunology and molecular biology), running (generally slowly), reading (articles and books), riding (bikes), and relaxing (with family and friends).
Specialty/Subspecialty Fellows
Class of 2025-2026
Perry Rabin
Specialty: Pulmonary Hypertension
Residency: Rush University Medical Center, Chicago, IL
PCCM Fellowship: Virginia Commonwealth University, Richmond, VA
Ahmed El-Moghraby
Specialty: Interventional Pulmonology
Residency: Western Reserve Health Education/NEOMED - Youngstown, OH
PCCM Fellowship: The Christ Hospital – Cincinnati, OH
Michelle Imperio
Specialty: Interventional Pulmonology
Residency: Loma Linda University Health
PCCM Fellowship: Loma Linda University, Loma Linda, CA