Physicians who bring expertise, knowledge and passion

Our clinical investigators bring a wealth of knowledge and leadership to our organization. With a full range of specialties and interests, they work actively and onsite with our research teams to deliver the most reliable, comprehensive data available in the industry.


Jefrey D. Lieberman, MD
Specialty: Rheumatology
Board Certification: Rheumatology and Internal Medicine

Dr. Lieberman graduated from Ohio State University School of Medicine and completed his internship and residency at the Cleveland Clinical Foundation and fellowship in Rheumatology & Immunology at Emory University.
He currently holds appointments as Chief of Medicine, Dekalb Medical Center Medical, Consultant & National Spokesperson for Arthritis Foundation and Clinical Associate Professor Emory University School of Medicine.
Clinic Location:
2712 North Decatur Road
Decatur, GA. 30033

Mohammed Abubaker, MD
Marietta Rheumatology Associates, PC.
Board Certified Rheumatologist
Rheumatology Fellowship: Emory University

Dr. Abubaker completed his fellowship at Emory University School of Medicine in 2000. He was chief resident in Internal Medicine at Bridgeport Hospital. He is board certified in Internal Medicine and Rheumatology. He has published and presented several research papers in the American College of Rheumatology conferences. He enjoys sports, traveling, and social services.

Clinic Location:
670 North Ave
Marietta, GA 30060

Roel N. Querubin, MD
Marietta Rheumatology Associates, PC
Board Certified Rheumatologist
Rheumatology Fellowship: Emory University

Dr. Querubin is a Board Certified Rheumatologist and completed his Rheumatology fellowship at the Emory University School of Medicine. He graduated from the Georgia Institute of Technology in 1991 with a Bachelor of Science degree and attended Medical School at the Medical College of Georgia from 1991-1995. He then completed a three year Internal Residency program at the Atlanta Medical Center in 1998. He has been practicing Rheumatology in the Atlanta area since completing his Rheumatology Fellowship in 2000. Dr. Querubin has published articles and research in several National Rheumatology Journals and has presented at National Medical Meetings. His hobbies include music, golf, martial arts and he enjoys spending time with his family.

Clinic Location:
670 North Ave
Marietta, GA 30060

Maria N. Onuorah, ARNP

Maria is a Nationally Certified Nurse Practioner. She has over 17 years of experience in the areas of Rheumatology, Cardiology, Coronary Intensive Care, Elderly care and Home Health. Maria received her Bachelor of Science in Nursing and Master of Science in Nursing from Emory University. She lives in Atlanta with her husband and children. She enjoys reading, speed walking, and traveling with her family.


Thomas P. DeMarini, MD, FCCP, MBA, CPE

Dr. DeMarini has a bachelor’s degree in Psycholinguistics from Illinois State University , performed graduate work at the University of Illinois, and obtained his medical degree from Northwestern University Medical School. He completed an Internal Medicine Residency at Evanston Hospital at Northwestern University, where he was chosen as Chief Medical Resident. He obtained his Pulmonary and Critical Care training at Loyola University. Dr. DeMarini is Board Certified in Internal Medicine and Pulmonary Disease.
Dr. DeMarini has given numerous lectures on the topics of Asthma, Chronic Obstructive Lung Disease, Emphysema, Septic Shock, Ventilator Management, Pulmonary Embolism, Deep Vein Thrombosis, and Sleep Apnea. He has served as a Primary Investigator on multiple research studies and has been Chairman of the Pulmonary and Critical Care Departments of several Metro Atlanta Hospitals. He is the past Chief of Staff at DeKalb Medical Center and is the current Chief of Staff at Emory John’s Creek Hospital, where he serves on the Board of Trustees.
Dr. DeMarini obtained his Masters of Business Administration, MBA, from Kennesaw State University. He has also obtained a degree as a Certified Physician Executive, CPE. He is an Independent Medical Consultant and a Medical Legal Consultant. He has been recognized as an Atlanta Area Outstanding Pulmonary Physician in The Atlanta Magazine survey. Dr. DeMarini is the founder of Southeastern Lung Care.

Dr. DeMarini sees patients in our Decatur and Johns Creek offices.

Clinic Location:
2665 North Decatur Road
Suite 430
Decatur, GA 30033

C. Jonathan Wu, MD, FCCP

Dr. Wu has a Bachelor’s Degree in Physics from Peking University and his Medical Degree from Shanghai Medical University in China. He performed graduate work at the Georgia Institute of Technology and completed his Internal Medicine Residency training in NYU Downtown Hospital in New York. He finished his Pulmonary and Critical Care Fellowship training at Emory University Hospitals in Atlanta.
Dr. Wu currently serves as the chief of staff for Decatur LTAC hospital and chairs the Critical Care Committee at DeKalb Medical Center. He is board certified in Internal Medicine, Pulmonary Medicine, Sleep Medicine and Critical Care Medicine. He is a member of the American Thoracic Society, American College of Chest Physicians and American Academy of Sleep Medicine. His interests include Sepsis, ARDS, COPD and Sleep medicine.
Dr. Wu sees patients in our Decatur office.

Clinic Location:
2665 North Decatur Road
Suite 430
Decatur, GA 30033

Internal Medicine

Dharmaraj Patil, MD

  • Specialty: Internal Medicine and Gastroenterology
  • Board Certification: Internal Medicine
  • Training: Graduated from Karnatak Medical College in Hubli, India
Dr.Patil graduated from Karnataka Medical College in Hubli, Karnataka, India in 1976 and completed his post graduate medical training in England where he obtained the prestigious MRCP (UK) certification. ...more He trained as a Gastroenterologist and worked as a Consultant Gastroenterology at King Fahad Hospital, AL Baha, Saudi Arabia. Dr. Patil moved to US in 1994 and completed his Residency in Internal Medicine from Memorial Medical Center, Worcester, Massachusetts. He has been in Atlanta area since 1994 and started Metro Medical Associates in 1999. Dr. Patil has special interest in Gastroenterology and manages most gastrointestinal diseases and performs in office Gastroscopy and colonoscopy procedures for his patients.

Clinic Location:
11379 Southbridge Parkway
Suite A
Alpharetta, GA. 30022

CSI Research, Inc. Staff

Nancy Green, RN, BS
Research Director

Nancy is the founder and president and of CSI Research, Inc. Nancy is a graduate of State University of New York (SUNY) with degrees in Health Science/ Biology and Nursing. Nancy brings over 25 years of healthcare experience to CSI with 18 years of experience in clinical research. Nancy is actively involved in business development, patient recruitment and quality assurance. Nancy has conducted clinical trials in oncology, cardiology, internal medicine, pulmonology, chronic pain management and rheumatology. Raised in New York, Nancy resides in Alpharetta, GA.

Betsy Hillhouse, RN
Lead Research Coordinator

Betsy is a licensed Registered Nurse and has over 20 years of experience in healthcare. Her background includes the emergency room, medical/surgical, Internal Medicine, Pediatrics, and Rheumatology. Betsy joins us at CSI Research as the Lead Research Coordinator after serving for 15 years at Kaiser Permanente. Betsy has conducted clinical trials in Rheumatology, Lupus, Gout, COPD, and OIC. Betsy was raised in Canton Georgia and now resides in Cumming, GA.

Suzi DeFiesta
Research Administrator

Along with an Associates Degree in business, Suzi brings over 20 years of experience in Executive Administration to our team. After her years of service with the York Division of Borg Warner and as Assistant to the President and C.E.O. of a Chicago based money center bank, Suzi relocated to Atlanta with her husband and two children. Suzi enjoys running, traveling and spending time with her family and the color pink.

Legal Counsel

Richard Bryson

Richard S. Bryson is an attorney and Member Manager of Morris & Bryson, LLC and a proud Eagle Scout (“once an Eagle always an Eagle”). His practice is limited to trusts and business entities, estates, asset protection, incapacity planning and tax planning [including retirement asset strategies].

Richard is a contributing author to many legal, tax and financial publications. In addition he has provided lectures and presentations to hundreds of organizations and forums on estate planning, asset protection, retirement asset planning, and elder law issues.

He is a member of the National Academy of Elder Law Attorneys, State Bar of Georgia Fiduciary Section, Gwinnett County Bar Association’s Estate Planning and Probate Section, former co-chair of the Tax Section of the Chicago Bar Association, and former co-chair of the Elder Law Committee of the State Bar of Georgia.

4045 Smithtown Road, Suite A
Suwanee, Georgia 30024
Phone (770)932-5242
Fax (770)932-2352