Physical Sciences and Mathematics Commons^™

Correction Of Verication Bias Using Log-Linear Models For A Single Binaryscale Diagnostic Tests, Haresh Rochani, Hani M. Samawi, Robert L. Vogel, Jingjing Yin

Biostatistics Faculty Publications

In diagnostic medicine, the test that determines the true disease status without an error is referred to as the gold standard. Even when a gold standard exists, it is extremely difficult to verify each patient due to the issues of costeffectiveness and invasive nature of the procedures. In practice some of the patients with test results are not selected for verification of the disease status which results in verification bias for diagnostic tests. The ability of the diagnostic test to correctly identify the patients with and without the disease can be evaluated by measures such as sensitivity, specificity and predictive …

High Prevalence And Genetic Heterogeneity Of Rodent-Borne Bartonella Species On Heixiazi Island, China, Dong-Mei Li, Yong Hou, Xiu-Ping Song, Ying-Qun Fu, Gui-Chang Li, Ming Li, Marina E. Eremeeva, Hai-Xia Wu, Bo Pang, Yu-Juan Yue, Ying Huang, Liang Lu, Jun Wang, Qi-Yong Liu

Environmental Health Sciences Faculty Publications

We performed genetic analysis of Bartonella isolates from rodent populations from Heixiazi Island in northeast China. Animals were captured at four sites representing grassland and brushwood habitats in 2011 and examined for the prevalence and genetic diversity of Bartonella species, their relationship to their hosts, and geographic distribution. A high prevalence (57.7%) and a high diversity (14 unique genotypes which belonged to 8 clades) of Bartonella spp. were detected from 71 rodents comprising 5 species and 4 genera from 3 rodent families. Forty-one Bartonella isolates were recovered and identified, including B. taylorii, B. japonica, B. coopersplainsensis, B. grahamii, B. washoensis …

Monitoring For Adverse Events Post Marketing Approval Of Drugs, Karl E. Peace, Macaulay Okwuokenye

Biostatistics Faculty Publications

This brief communication provides information to those developing monitoring plans for serious adverse events (SAE’s) following regulatory approval of a new drug. In addition, we (1) illustrate how many patients would need to be treated in order to have high confidence of seeing at least 1 pre-specified SAE, (2) show that absence of proof of a SAE is not proof of absence of that SAE, and (3) identify statistical methodology that could be used for formal statistical monitoring of SAE’s.

Size And Power Of Tests Of Hypotheses On Survival Parameters From The Lindley Distribution With Covariates, Macaulay Okwuokenye, Karl E. Peace

Biostatistics Faculty Publications

The Lindley model is considered as an alternative model facilitating analyses of time-to-event data with covariates. Covariate information is incorporated using the Cox’s proportional hazard model with the Lindley model at the timedependent component. Simulation studies are performed to assess the size and power of tests of hypotheses on parameters arising from maximum likelihood estimators of parameters in the Lindley model. Results are contrasted with that arising from Cox’s partial maximum likelihood estimator. The Linley model is used to analyze a publicly available data set and contrasted with other models.

Joint Modeling Of Treatment Effect On Time-To-Event Endpoint And Safety Covariates In Control Clinical Trial Data Analysis, Kao-Tai Tsai, Karl E. Peace

Biostatistics Faculty Publications

It is a common practice to perform a separate analysis of efficacy and safety data from clinical trials to estimate the benefit and risk aspects of a particular treatment regimen. However, by doing so, one is likely to miss the complete picture of the treatment effect given that these data are generated from the same study subjects and therefore most likely will be correlated. Therefore, it is desirable to analyze these data jointly to obtain a more complete profile of the treatment regimen. A substantial number of statistical methodologies have been proposed in the last decade to model the time-to-event …

Inequalities And Approximations Of Weighted Distributions By Lindley Reliability Measures, And The Lindley-Cox Model With Applications, Broderick O. Oluyede, Macaulay Okwuokenye, Karl E. Peace

Biostatistics Faculty Publications

In this note, stochastic comparisons and results for weighted and Lindley models are presented. Approximation of weighted distributions via Lindley distribution in the class of increasing failure rate (IFR) and decreasing failure rate (DFR) weighted distributions with monotone weight functions are obtained including approximations via the length-biased Lindley distribution. Some useful bounds and moment-type inequality for weighted life distributions and applications are presented. Incorporation of covariates into Lindley model is considered and an application to illustrate the usefulness and applicability of the proposed Lindley-Cox model is given.

Challenges Posed By Tick-Borne Rickettsiae: Eco- Epidemiology And Public Health Implications, Marina E. Eremeeva, Gregory A. Dasch

Environmental Health Sciences Faculty Publications

Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted …

How Long Does That 10-Year Smoke Alarm Really Last? A Survival Analysis Of Smoke Alarms Installed Through The Saife Program In Rural Georgia, Haresh Rochani, Valamar Malika Reagon, Steve Davidson

Biostatistics Faculty Publications

Background: When functioning properly, a smoke alarm alerts individuals in the residence that smoke is near the alarm. Smoke alarms serve as a primary prevention mechanism to abate morbidity and mortality related to residential fires.

Methods: Using survival analysis, we examined the length of operability of 10-year lithium battery powered smoke alarms installed through the Georgia Public Health/CDC SAIFE program in Moultrie, Georgia. Attempts were made to reach all homes in the city limits. The premise of the study is that geographic clusters (in the case of Moultrie city quadrants) are associated with decreases in the length of time that …

Total Synthesis Of Biologically Active Natural And Unnatural Products, Julia Heimberger

Electronic Theses and Dissertations

Herbarin A and B were isolated from the fungal strains of Cladosporium herbarum found in marine sponges Aplysina aerophoba and Callyspongia aerizusa. Total synthesis of Herbarin A and B was achieved by carrying out a multi-step synthesis approach, and the antioxidant properties were evaluated using FRAP assay. Toxicity of these compounds was determined using a zebrafish embryo model. Furthermore, synthesis of C-6 alkyl-azaarene derivatives of nucleosides by Csp3-H bond functionalization were investigated. Effective incorporation of 2-methylazaarene moiety at the C-6 position of the protected inosine nucleoside provided a new class of compounds with anticipated enhanced biological activity.