Posts classified under: Methods

Christina M. Ramirez, PhD research interests generally relate to uncovering the mechanisms behind HIV and viral pathogenesis. To this end, Christina works closely with investigators in the clinical and basic sciences. Christina is particularly interested in drug resistance mutation/recombination, viral fitness and HIV co-receptor utilization. Christina works to develop methods to understand the evolutionary dynamics of gene regions under the selective pressure of the host immune system and antiretroviral. Christina also is interested in complex, high-dimensional data analysis where we have large p and small n.  This has led to the development of machine learning methods for complex data with correlation.

FEATURED PUBLICATIONS:

1. Shao, S., Henrique Ribeiro, P., Ramirez, C. M., & Moore, J. H. (2024). A review of feature selection strategies utilizing graph data structures and Knowledge Graphs. Briefings in bioinformatics, 25(6), bbae521.

2. Zhang, J., Sehl, M. E., Shih, R., Breen, E. C., Li, F., Lu, A. T., Bream, J. H., Duggal, P., Martinson, J., Wolinsky, S. M., Martinez-Maza, O., Ramirez, C. M., Horvath, S., & Jamieson, B. D. (2024). Effects of highly active antiretroviral therapy initiation on epigenomic DNA methylation in persons living with HIV. Frontiers in bioinformatics, 4, 1357889.

3. Sehl, M. E., Breen, E. C., Shih, R., Li, F., Zhang, J., Langfelder, P., Horvath, S., Bream, J. H., Duggal, P., Martinson, J., Wolinsky, S. M., Martinez-Maza, O., Ramirez, C. M., & Jamieson, B. D. (2024). Decreased but persistent epigenetic age acceleration is associated with changes in T-cell subsets after initiation of highly active antiretroviral therapy in persons living with HIV. Frontiers in bioinformatics, 4, 1356509.

Last updated: 11/25/2025

W. Scott Comulada, DrPH, is a Professor-in-Residence with joint appointments in the UCLA Department of Psychiatry and Biobehavioral Sciences and the Department of Health Policy and Management. He also directs the Semel Institute Center for Community Health, leads the subcommittee on XR in Health and Wellness for the UCLA XR Initiative, serves as a board member for the South Central Family Health Center in Los Angeles, and has served in various roles for the CHIPTS Methods Core since 2007. He has been a statistician on numerous HIV clinical trials and observational studies, including his role as an Analytic Core Project Lead for a U19 funded through the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN). His methodological interests have focused on the analysis of longitudinal data and the development of predictive algorithms using machine learning and artificial intelligence methods. His current research focuses on the development of large language model chatbots and virtual simulations to support clinical training and patient care. Topics for courses he teaches reflect his research interests. He has taught graduate courses on statistical methods that cover longitudinal modeling, causal inference, and machine learning methods in the Departments of Biostatistics and Health Policy and Management. He has served on 24 dissertation committees, including committees in the Departments of Biostatistics, Computer Science, Epidemiology, and Health Policy and Management. He has also mentored a junior faculty member through the ATN National Diversity Scholars Program, postdoctoral scholars through a T32 HIV training fellowship, and doctoral students through F31 awards.

Contact: wcomulada@mednet.ucla.edu

FEATURED PUBLICATIONS:

1. Lee, B. D., Davis, L., Bailliard, A., Gori, Y., Gertsch, W., Comulada, W. S., Cuddeback, G., Resnick, J., Bennett, J., Jackson, T., Sherin, J., Lovelace, A., Mansfield, D., Cope, E., Henwood, B. F., & Bromley, E. (2025). The Homeless Outreach Behavioral Screen (HOBS): A Brief Scale for Identifying Need for Mental Health Evaluation Among Unsheltered Populations. Community mental health journal, 10.1007/s10597-025-01520-6. Advance online publication.

2. Comulada, W. S., McQueen, C., & Lang, C. M. (2025). Empowering tomorrow’s public health researchers and clinicians to develop digital health interventions using chatbots, virtual reality, and other AI technologies. Frontiers in public health, 13, 1577076.

3. Arnold, E. M., Rotheram-Borus, M. J., Christodoulou, J., Yalch, M. M., Murphy, D. A., Norwood, P., Comulada, W. S., Swendeman, D., & ATN CARES Team (2025). Increasing Sustained Viral Suppression Among Youth Living with HIV: A Randomized Controlled Trial of Stepped Care Intervention. AIDS and behavior, 29(7), 2287–2298.

Chunqing Lin, PhD, is an Associate Professor-in-Residence in the Department of Psychiatry and Biobehavioral Sciences at University of California, Los Angeles (UCLA) David Geffen School of Medicine. She received her PhD in epidemiology from UCLA. Dr. Lin’s research expertise lies in implementation science and behavioral studies aimed at addressing health challenges and promoting the well-being of populations at risk for or living with HIV, including people who use drugs, sexual minority populations, and women with HIV. Her work focuses on developing culturally sensitive strategies to facilitate the adoption of evidence-based practices and ultimately reduce health disparities among these vulnerable groups, particularly in resource-limited settings.

Contact: lincq@ucla.edu

FEATURED PUBLICATIONS:

2. Kitro, A., Krasaewes, K., Sapbamrer, R., Supindham, T., Tangmunkongvorakul, A., Aurpibul, L., Sripan, P., Utaipat, U., Hongjaisee, S., Lee, S. J., Lin, C., & Srithanaviboonchai, K. (2025). Depression and quality of life among Thai and migrant sex workers in Thailand: a cross-sectional study. Journal of affective disorders, 394(Pt B), 120593. Advance online publication.

3. Gonzalez, S. T., Horigian, V. E., Cheng, H., Hagedorn, H. J., Shmueli-Blumberg, D., Campbell, C. I., Lin, C., Rogers, E., Baloh, J., Hilton, R., Vena, A., McNeely, J., & Glass, J. E. (2025). Implementation outcomes included in NIDA Clinical Trials Network (CTN) studies: A systematic review of studies conducted over 20 years. Journal of substance use and addiction treatment, 209811. Advance online publication.

Last updated: 11/21/2025

Thomas R. Belin, PhD, is a Professor in the UCLA Department of Biostatistics, where he has been on the faculty since 1993, and the UCLA Department of Psychiatry and Biobehavioral Sciences, where he has held a joint appointment since 1995.  His methodological interests have focused on causal inference and handling incomplete data, and his extensive collaborative work has included involvement with the Center for HIV Identification, Prevention, and Treatments Services (CHIPTS) since its inception.  He also has had wide-ranging experience studying health-services interventions and quality-of-life outcomes, including serving as chair of the Design Committee of the Community Partners In Care study (K. Wells, L. Jones, co-PIs), a community-partnered participatory research project that received the 2014 Team Science Award from the Association for Clinical and Translational Science and the 2015 Annual Award from the Community-Campus Partnerships for Health organization.  Within the UCLA Department of Biostatistics, he has supervised 15 doctoral dissertations to completion and has served on more than 50 other doctoral dissertation committees, receiving an award from the UCLA Public Health Student Association in 2015 for outstanding advising and mentoring of doctoral students.  Since 2012 he has additionally served as Vice Chair of the department.  He was elected Fellow of the American Statistical Association in 2004, and in 2005 he received the Washington (D.C.) Statistical Society Gertrude M. Cox Award honoring a statistician making “significant contributions to statistical practice.”  His professional activity also includes being a member of the American Statistical Association Committee on Professional Ethics.

Contact: tbelin@mednet.ucla.edu

FEATURED PUBLICATIONS:

1. Arena, P. J., Bandak, J., Jeon, C. Y., Gadoth, A., Hoff, N. A., Nkamba, D. M., Nianogo, R. A., Belin, T. R., Nielsen-Saines, K., Kaba, D., & Rimoin, A. W. (2024). The impact of COVID-19 mitigation measures on neonatal health outcomes in sub-Saharan Africa: A systematic review and meta-analysis. Public health, 238, 108–116. Advance online publication.

2. Li, M. J., Chau, B., Belin, T., Carmody, T., Jha, M. K., Marino, E. N., Trivedi, M., & Shoptaw, S. J. (2024). Extended observation of reduced methamphetamine use with combined naltrexone plus bupropion in the ADAPT-2 trial. Addiction (Abingdon, England), 119(10), 1840–1845.

3. Shaw, C., Wu, Y., Zimmerman, S. C., Hayes-Larson, E., Belin, T. R., Power, M. C., Glymour, M. M., & Mayeda, E. R. (2023). Comparison of Imputation Strategies for Incomplete Longitudinal Data in Life-Course Epidemiology. American journal of epidemiology, 192(12), 2075–2084.

Last updated: 11/18/2025

Sung-Jae Lee, PhD, is a Professor-in-Residence in the Department of Psychiatry and Biobehavioral Sciences, UCLA David Geffen School of Medicine, with a joint appointment in the Department of Epidemiology, UCLA Fielding School of Public Health. He is the Director of Research and Evaluation at the Nathanson Family Resilience Center, Division of Population Behavioral Health. Dr. Lee’s research, training, and community engagement work have been strongly shaped by his pursuit of addressing health disparities affecting HIV prevention and care among vulnerable communities impacted by HIV/AIDS. His methods expertise includes conjoint analysis to assess consumer preferences in behavioral and biomedical strategies (e.g. HIV vaccines, pre-exposure prophylaxis acceptability, HIV testing, dual testing for syphilis and HIV, and long acting injectables for HIV treatment/prevention). Dr. Lee loves teaching and mentoring. He serves as an advisor to many masters and doctoral students in the Department of Epidemiology. He co-directs the UCLA Fogarty AIDS Training Programs in Thailand and Myanmar, and is a Key Faculty for UCLA Fogarty Training Programs in Vietnam and Cambodia, and enjoys mentoring scholars from Thailand, Myanmar, Vietnam, and Cambodia.

FEATURED PUBLICATIONS: