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Effect Of Study Design On Sample Size In Studies Intended To Evaluate Bioequivalence Of Inhaled Short-Acting Β-Agonist Formulations, Yaohui Zeng, Sachinkumar Singh, Kai Wang, Richard C. Ahrens 2018 University of Iowa

Effect Of Study Design On Sample Size In Studies Intended To Evaluate Bioequivalence Of Inhaled Short-Acting Β-Agonist Formulations, Yaohui Zeng, Sachinkumar Singh, Kai Wang, Richard C. Ahrens

Stead Family Department of Pediatrics Publications

Pharmacodynamic studies that use methacholine challenge to assess bioequivalence of generic and innovator albuterol formulations are generally designed per published Food and Drug Administration guidance, with 3 reference doses and 1 test dose (3-by-1 design). These studies are challenging and expensive to conduct, typically requiring large sample sizes. We proposed 14 modified study designs as alternatives to the Food and Drug Administration-recommended 3-by-1 design, hypothesizing that adding reference and/or test doses would reduce sample size and cost. We used Monte Carlo simulation to estimate sample size. Simulation inputs were selected based on published studies and our own experience with ...


Cheating The Cheaters: Spatial Dynamics In The Evolutionary Stability Of Antibiotic Resistance, Devin Akman 2017 University of Illinois at Urbana-Champaign

Cheating The Cheaters: Spatial Dynamics In The Evolutionary Stability Of Antibiotic Resistance, Devin Akman

Annual Symposium on Biomathematics and Ecology: Education and Research

No abstract provided.


Uncertainty Of 1-D Fluid Models In Patients With Pulmonary Hypertension, Mitchel J. Colebank 2017 North Carolina State University

Uncertainty Of 1-D Fluid Models In Patients With Pulmonary Hypertension, Mitchel J. Colebank

Biology and Medicine Through Mathematics Conference

No abstract provided.


Detecting And Evaluating Therapy Induced Changes In Radiomics Features Measured From Non-Small Cell Lung Cancer To Predict Patient Outcomes, Xenia J. Fave 2017 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Detecting And Evaluating Therapy Induced Changes In Radiomics Features Measured From Non-Small Cell Lung Cancer To Predict Patient Outcomes, Xenia J. Fave

UT GSBS Dissertations and Theses (Open Access)

The purpose of this study was to investigate whether radiomics features measured from weekly 4-dimensional computed tomography (4DCT) images of non-small cell lung cancers (NSCLC) change during treatment and if those changes are prognostic for patient outcomes or dependent on treatment modality. Radiomics features are quantitative metrics designed to evaluate tumor heterogeneity from routine medical imaging. Features that are prognostic for patient outcome could be used to monitor tumor response and identify high-risk patients for adaptive treatment. This would be especially valuable for NSCLC due to the high prevalence and mortality of this disease.

A novel process was designed to ...


Mathematical Models Of The Inflammatory Response In The Lungs, Sarah B. Minucci 2017 Virginia Commonwealth University

Mathematical Models Of The Inflammatory Response In The Lungs, Sarah B. Minucci

Theses and Dissertations

Inflammation in the lungs can occur for many reasons, from bacterial infections to stretch by mechanical ventilation. In this work we compare and contrast various mathematical models for lung injuries in the categories of acute infection, latent versus active infection, and particulate inhalation. We focus on systems of ordinary differential equations (ODEs), agent-based models (ABMs), and Boolean networks. Each type of model provides different insight into the immune response to damage in the lungs. This knowledge includes a better understanding of the complex dynamics of immune cells, proteins, and cytokines, recommendations for treatment with antibiotics, and a foundation for more ...


Modeling The Spread Of The Zika Virus At The 2016 Olympics, Triona Matheson, Brian Satterthwaite, Hannah Callender Highlander 2017 University of Portland

Modeling The Spread Of The Zika Virus At The 2016 Olympics, Triona Matheson, Brian Satterthwaite, Hannah Callender Highlander

Mathematics Faculty Publications and Presentations

The Zika Virus is an arbovirus that is spread by mosquitoes of the Aedes genus and causes mild fever-like symptoms. It is strongly associated with microcephaly, a condition that affects development of fetal brains. With the recent emergence of Zika in Brazil, we develop an agent-based model to track mosquitoes and humans throughout the 2016 Olympics in Rio de Janeiro to investigate how the Olympics might affect the spread of the virus. There are many unknowns regarding the spread and prevalence of Zika, with approximately 80% of infected individuals unaware of their infectious status. We therefore discuss results of experiments ...


Assessing The Potential Clinical Impact Of Variable Biological Effectiveness In Proton Radiotherapy, Christopher R. Peeler Ph.D. 2016 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences

Assessing The Potential Clinical Impact Of Variable Biological Effectiveness In Proton Radiotherapy, Christopher R. Peeler Ph.D.

UT GSBS Dissertations and Theses (Open Access)

It has long been known that proton radiotherapy has an increased biological effectiveness compared to traditional x-ray radiotherapy. This arises from the clustered nature of DNA damage produced by the energy deposition of protons along their tracks in medium. This effect is currently quantified in clinical settings by assigning protons a relative biological effectiveness (RBE) value of 1.1 corresponding to 10% increased effectiveness compared to photon radiation. Numerous studies have shown, however, that the RBE value of protons is variable and can deviate substantially from 1.1, but experimental data on RBE and clinical evidence of its variability remains ...


The Effects Of Scarring On Face Recognition, Kevin J. Chan 2016 Purdue University

The Effects Of Scarring On Face Recognition, Kevin J. Chan

Open Access Theses

The focus of this research is the effects of scarring on face recognition. Face recognition is a common biometric modality implemented for access control operations such as customs and borders. The recent report from the Special Group on Issues Affecting Facial Recognition and Best Practices for their Mitigation highlighted scarring as one of the emerging challenges. The significance of this problem extends to the ISO/IEC and national agencies are researching to enhance their intelligence capabilities. Data was collected on face images with and without scars, using theatrical special effects to simulate scarring on the face and also from subjects ...


A Comparison Of Stride Length And Lower Extremity Kinematics During Barefoot And Shod Running In Well Trained Distance Runners, Peter Francis, James Ledingham, Sarah B. Clarke PhD, DJ Collins, Philip Jakeman 2016 Leeds Beckett University

A Comparison Of Stride Length And Lower Extremity Kinematics During Barefoot And Shod Running In Well Trained Distance Runners, Peter Francis, James Ledingham, Sarah B. Clarke Phd, Dj Collins, Philip Jakeman

Journal Articles

Stride length, hip, knee and ankle angles were compared during barefoot and shod running on a treadmill at two speeds. Nine well-trained (1500m time: 3min:59.80s ± 14.7 s) male (22 ±3 years; 73 ±9 kg; 1.79 ±0.4 m) middle distance (800 m – 5,000 m) runners performed 2 minutes of running at 3.05 m·s-1 and 4.72 m·s-1 on an treadmill. This approach allowed continuous measurement of lower extremity kinematic data and calculation of stride length. Statistical analysis using a 2X2 factorial ANOVA revealed speed to have a main effect on ...


Mathematical Models Of Hiv And Hpv Coinfection, Samantha Erwin, Meghna Verma, Vida Abedi, Raquel Hontecillas-Magarzo, Stefan Hoops, Josep Bassaganya-Riera, Stanca M. Ciupe 2016 Virginia Polytechnic Institute and State University

Mathematical Models Of Hiv And Hpv Coinfection, Samantha Erwin, Meghna Verma, Vida Abedi, Raquel Hontecillas-Magarzo, Stefan Hoops, Josep Bassaganya-Riera, Stanca M. Ciupe

Biology and Medicine Through Mathematics Conference

No abstract provided.


Strategies Of Balancing: Regulation Of Posture As A Complex Phenomenon, Allison Leich Hilbun 2016 East Tennessee State Universtiy

Strategies Of Balancing: Regulation Of Posture As A Complex Phenomenon, Allison Leich Hilbun

Electronic Theses and Dissertations

The complexity of the interface between the muscular system and the nervous system is still elusive. We investigated how the neuromuscular system functions and how it is influenced by various perturbations. Postural stability was selected as the model system, because this system provides complex output, which could indicate underlying mechanisms and feedback loops of the neuromuscular system. We hypothesized that aging, physical pain, and mental and physical perturbations affect balancing strategy, and based on these observations, we constructed a model that simulates many aspects of the neuromuscular system. Our results show that aging changes the control strategy of balancing from ...


Power Analysis In Applied Linear Regression For Cell Type-Specific Differential Expression Detection, Edmund Glass 2016 Virginia Commonwealth University

Power Analysis In Applied Linear Regression For Cell Type-Specific Differential Expression Detection, Edmund Glass

Theses and Dissertations

The goal of many human disease-oriented studies is to detect molecular mechanisms different between healthy controls and patients. Yet, commonly used gene expression measurements from any tissues suffer from variability of cell composition. This variability hinders the detection of differentially expressed genes and is often ignored. However, this variability may actually be advantageous, as heterogeneous gene expression measurements coupled with cell counts may provide deeper insights into the gene expression differences on the cell type-specific level. Published computational methods use linear regression to estimate cell type-specific differential expression. Yet, they do not consider many artifacts hidden in high-dimensional gene expression ...


Analyzing Direct Effects In Randomized Trials With Secondary Interventions: An Application To Hiv Prevention Trials, Michael Rosenblum, Nicholas Jewell, Mark van der Laan, Steven Shiboski, Ariane van der Straten, Nancy Padian 2015 Johns Hopkins University

Analyzing Direct Effects In Randomized Trials With Secondary Interventions: An Application To Hiv Prevention Trials, Michael Rosenblum, Nicholas Jewell, Mark Van Der Laan, Steven Shiboski, Ariane Van Der Straten, Nancy Padian

Michael Rosenblum MD

The `Methods for improving reproductive health in Africa' trial is a recently completed randomized trial that investigated the effect of diaphragm and lubricant gel use in reducing infection by the human immunodeficiency virus (HIV) among susceptible women. 5045 women were randomly assigned to either the active treatment arm or not. Additionally, all subjects in both arms received intensive condom counselling and provision, the `gold standard' HIV prevention barrier method. There was much lower reported use of condoms in the intervention arm than in the control arm, making it difficult to answer important public health questions based solely on the intention-to-treat ...


Diaphragm And Lubricant Gel For Prevention Of Hiv Acquisition In Southern African Women: A Randomised Controlled Trial, Nancy Padian, Ariane van der Straten, Gita Ramjee, Tsungai Chipato, Guy de Bruyn, Kelly Blanchard, Stephen Shiboski, Elizabeth Montgomery, Heidi Fancher, Helen Cheng, Michael Rosenblum, Mark van der Laan, Nicholas Jewell, James McIntyre 2015 Johns Hopkins University

Diaphragm And Lubricant Gel For Prevention Of Hiv Acquisition In Southern African Women: A Randomised Controlled Trial, Nancy Padian, Ariane Van Der Straten, Gita Ramjee, Tsungai Chipato, Guy De Bruyn, Kelly Blanchard, Stephen Shiboski, Elizabeth Montgomery, Heidi Fancher, Helen Cheng, Michael Rosenblum, Mark Van Der Laan, Nicholas Jewell, James Mcintyre

Michael Rosenblum MD

Background Female-controlled methods of HIV prevention are urgently needed. We assessed the effect of provision of latex diaphragm, lubricant gel, and condoms (intervention), compared with condoms alone (control) on HIV seroincidence in women in South Africa and Zimbabwe. Methods We did an open-label, randomised controlled trial in HIV-negative, sexually active women recruited from clinics and community-based organisations, who were followed up quarterly for 12—24 months (median 21 months). All participants received an HIV prevention package consisting of pre-test and post-test counselling about HIV and sexually transmitted infections, testing, treatment of curable sexually transmitted infections, and intensive risk-reduction counselling. The ...


The Risk Of Virologic Failure Decreases With Duration Of Hiv Suppression, At Greater Than 50% Adherence To Antiretroviral Therapy., Michael Rosenblum, Steven Deeks, Mark van der Laan, David Bangsberg 2015 Johns Hopkins University

The Risk Of Virologic Failure Decreases With Duration Of Hiv Suppression, At Greater Than 50% Adherence To Antiretroviral Therapy., Michael Rosenblum, Steven Deeks, Mark Van Der Laan, David Bangsberg

Michael Rosenblum MD

Background We hypothesized that the percent adherence to antiretroviral therapy necessary to maintain HIV suppression would decrease with longer duration of viral suppression. Methodology Eligible participants were identified from the REACH cohort of marginally housed HIV infected adults in San Francisco. Adherence to antiretroviral therapy was measured through pill counts obtained at unannounced visits by research staff to each participant's usual place of residence. Marginal structural models and targeted maximum likelihood estimation methodologies were used to determine the effect of adherence to antiretroviral therapy on the probability of virologic failure during early and late viral suppression. Principal Findings A ...


Interaction Of Alu Polymorphisms And Novel Measures Of Discrimination In Association With Blood Pressure In African Americans Living In Tallahassee, Alexis C. Boulter, Jackyn Quinlan, Aida T. Miró-Herrans, Laurel N. Pearson, Nubiana L. Todd, Clarence C. Gravlee, Connie J. Mulligan 2015 University of Florida

Interaction Of Alu Polymorphisms And Novel Measures Of Discrimination In Association With Blood Pressure In African Americans Living In Tallahassee, Alexis C. Boulter, Jackyn Quinlan, Aida T. Miró-Herrans, Laurel N. Pearson, Nubiana L. Todd, Clarence C. Gravlee, Connie J. Mulligan

Human Biology Open Access Pre-Prints

African Americans are 40% more likely to be afflicted with hypertension in comparison to non-Hispanic, white Americans, resulting in a 30% higher instance of mortality due to cardiovascular disease. There is debate about the relative contributions of genetic and sociocultural risk factors to the racial disparity in hypertension.

We assayed three Alu insertion polymorphisms located in the angiotensin-1-converting enzyme (ACE), tissue plasminogen activator (PLAT), and with no-lysine kinase 1 (WNK1) genes. We also estimated West African genetic ancestry and developed novel measures of perceived discrimination to create a biocultural model of blood pressure among African- American adults in Tallahassee, FL ...


Mathematical Modeling And Simulations Of The Pathophysiology Of Type-2 Diabetes Mellitus, Frank K. Nani, Mingxian Jin 2015 Fayetteville State University

Mathematical Modeling And Simulations Of The Pathophysiology Of Type-2 Diabetes Mellitus, Frank K. Nani, Mingxian Jin

Faculty Working Papers

The pathophysiology of Type 2 Diabetes Mellitus (T2DM) is modelled using a coupled system of non-linear deterministic differential equations. An attempt is made to construct to a clinically plausible mathematical model that incorporates the homeostasis associated with endocrinological regulation of glucose and glycogen levels in the human body, by the hormones, insulin and glucagon. The model variables include the concentrations of glucose in the venous blood plasma, the concentration of glycogen in the liver/tissues, the concentration of the hormone glucagon, and the concentration of insulin in the venous blood plasma. The physiological interactions between the model parameters are depicted ...


A Receiver Operating Characteristic, Curve-Logistic Regression Based Variable Selection Method, Rajani Kaimal 2015 Oregon Health & Science University

A Receiver Operating Characteristic, Curve-Logistic Regression Based Variable Selection Method, Rajani Kaimal

Scholar Archive

Biomarker discovery is a challenging process. It is rare that a single marker can accurately classify an outcome. Often, classification is improved by finding a combination of markers that can better distinguish between patients with and without a condition of interest. The present study describes a novel method which can potentially function as a diagnostic algorithm to isolate a parsimonious combination of markers that has good classification properties. The method takes advantage of the well-studied properties of receiver operating characteristic (ROC) curves and logistic regression models to select combination of variables that maximize the partial area under ROC (pAUROC), a ...


Movement Path Tortuosity Predicts Compliance With Therapeutic Behavioral Prompts In Patients With Traumatic Brain Injury, William Kearns, James Fozard, Roger Ray, Steven Scott, Jan Jasiewicz, Craig Pagano 2014 University of South Florida

Movement Path Tortuosity Predicts Compliance With Therapeutic Behavioral Prompts In Patients With Traumatic Brain Injury, William Kearns, James Fozard, Roger Ray, Steven Scott, Jan Jasiewicz, Craig Pagano

William D. Kearns, PhD

Objective: Rehabilitation of patients with traumatic brain injury typically includes therapeutic prompts for keeping appointments and adhering to medication regimens. Level of cognitive impairment may significantly affect a traumatic brain injury victim’s ability to benefit from text-based prompting. We tested the hypothesis that spatial disorientation as measured by movement path tortuosity during ambulation would be associated with poorer compliance with automated prompts by veterans actively being treated for traumatic brain injury. Setting: Clinical polytrauma center. Participants: Ten (1 female) veteran patients mean age = 35.4 (SD = 12.4) years. Design: Small group correlational study without random assignment. Main Measures ...


Decreased Movement Path Tortuosity Is Associated With Improved Functional Status In Tbi Patients., William Kearns, Steven Scott, James Fozard, Christina Dillahunt-Aspillaga, Jan Jasiewicz 2014 University of South Florida

Decreased Movement Path Tortuosity Is Associated With Improved Functional Status In Tbi Patients., William Kearns, Steven Scott, James Fozard, Christina Dillahunt-Aspillaga, Jan Jasiewicz

William D. Kearns, PhD

Objective: To determine if movement path tortuosity in everyday ambulation decreases in Veterans being treated in a residential setting for traumatic brain injury. Elevated path tortuosity is observed in assisted living facility residents with cognitive impairment and at risk for falls, and tortuosity may decrease over the course of cognitive rehabilitation received by the Veterans. If observed, decreased tortuosity may be linked to improved clinical outcomes. Design: Longitudinal observational study without random assignment. Setting: Veterans Affairs Medical Center inpatient residential polytrauma treatment facility. Patients: Twenty-two Veterans enrolled in a postacute predischarge residential polytrauma treatment facility. Interventions: None, observation-only. Main Outcome ...


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