Physical Sciences and Mathematics Commons^™

Using Predator Carrying Capacity For A Pathogenic Vector-Dynamic Differential Model, Rosahn Bhattarai

Georgia State Undergraduate Research Conference

No abstract provided.

Analysis Of New Hiv-1 Inhibitors As Potential Antiviral Agents For Hiv-2, Rowan Brothers

Georgia State Undergraduate Research Conference

No abstract provided.

Functional Organization And Restoration Of The Brain Motor-Execution Network After Stroke And Rehabilitation, Sahil Bajaj, Andrew Butler, Daniel Drake, Mukesh Dhamala

Physics and Astronomy Faculty Publications

Multiple cortical areas of the human brain motor system interact coherently in the low frequency range (<0.1 Hz), even in the absence of explicit tasks. Following stroke, cortical interactions are functionally disturbed. How these interactions are affected and how the functional organization is regained from rehabilitative treatments as people begin to recover motor behaviors has not been systematically studied. We recorded the intrinsic functional magnetic resonance imaging (fMRI) signals from 30 participants: 17 young healthy controls and 13 aged stroke survivors. Stroke participants underwent mental practice (MP) or both mental practice and physical therapy (MP+PT) within 14–51 days following stroke. We investigated the network activity of five core areas in the motor-execution network, consisting of the left primary motor area (LM1), the right primary motor area (RM1), the left pre-motor cortex (LPMC), the right pre-motor cortex (RPMC) and the supplementary motor area (SMA). We discovered that (i) the network activity dominated in the frequency range 0.06–0.08 Hz for all the regions, and for both able-bodied and stroke participants (ii) the causal information flow between the regions: LM1 and SMA, RPMC and SMA, RPMC and LM1, SMA and RM1, SMA and LPMC, was reduced significantly for stroke survivors (iii) the flow did not increase significantly after MP alone and (iv) the flow among the regions during MP+PT increased significantly. We also found that sensation and motor scores were significantly higher and correlated with directed functional connectivity measures when the stroke-survivors underwent MP+PT but not MP alone. The findings provide evidence that a combination of mental practice and physical therapy can be an effective means of treatment for stroke survivors to recover or regain the strength of motor behaviors, and that the spectra of causal information flow can be used as a reliable biomarker for evaluating rehabilitation in stroke survivors.

Development Of A Safe And Efficient Near-Infrared Diagnostic Method For Alzheimer's Disease, Joseph Tawney

Georgia State Undergraduate Research Conference

No abstract provided.

The Effect Of The R1648h Sodium Channel Mutation On Neuronal Excitability: A Model Study, Christopher Locandro, Robert Clewley

Georgia State Undergraduate Research Conference

No abstract provided.

Efficient Error Correction For Next-Generation Sequencing Of Viral Amplicons, Pavel Skums, Zoya Dimitrova, David S. Campo, Gilberto Vaughan, Livia Rossi, Joseph C. Forbi, Jonny Yokosawa, Alexander Zelikovskiy, Yury Khudyakov

Computer Science Faculty Publications

Background: Next-generation sequencing allows the analysis of an unprecedented number of viral sequence variants from infected patients, presenting a novel opportunity for understanding virus evolution, drug resistance and immune escape. However, sequencing in bulk is error prone. Thus, the generated data require error identification and correction. Most error-correction methods to date are not optimized for amplicon analysis and assume that the error rate is randomly distributed. Recent quality assessment of amplicon sequences obtained using 454-sequencing showed that the error rate is strongly linked to the presence and size of homopolymers, position in the sequence and length of the amplicon. All …

Additive And Multiplicative Hazards Modeling For Recurrent Event Data Analysis, Hyun J. Lim, Xu Zhang

Mathematics and Statistics Faculty Publications

Background: Sequentially ordered multivariate failure time or recurrent event duration data are commonly observed in biomedical longitudinal studies. In general, standard hazard regression methods cannot be applied because of correlation between recurrent failure times within a subject and induced dependent censoring. Multiplicative and additive hazards models provide the two principal frameworks for studying the association between risk factors and recurrent event durations for the analysis of multivariate failure time data.

Methods: Using emergency department visits data, we illustrated and compared the additive and multiplicative hazards models for analysis of recurrent event durations under (i) a varying baseline with a common …

Neuronbank: A Tool For Cataloging Neuronal Circuitry, Paul S. Katz, Robert Calin-Jageman, Akshaye Dhawan, Chad Frederick, Shuman Guo, Rasanjalee Dissanayaka, Naveen Hiremath, Wenjun Ma, Xiuyn Shen, Hsui C. Wang, Hong Yang, Sushil Prasad, Rajshekhar Sunderraman, Ying Zhu

Computer Science Faculty Publications

The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifi able neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe NeuronBank.org, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented …

Methods Of Competing Risks Analysis Of End-Stage Renal Disease And Mortality Among People With Diabetes, Hyun J. Lim, Xu Zhang, Roland Dyck, Nathaniel Osgood

Mathematics and Statistics Faculty Publications

Background: When a patient experiences an event other than the one of interest in the study, usually the probability of experiencing the event of interest is altered. By contrast, disease-free survival time analysis by standard methods, such as the Kaplan-Meier method and the standard Cox model, does not distinguish different causes in the presence of competing risks. Alternative approaches use the cumulative incidence estimator by the Cox models on cause-specific and on subdistribution hazards models. We applied cause-specific and subdistribution hazards models to a diabetes dataset with two competing risks (end-stage renal disease (ESRD) or death without ESRD) to measure …

Association Testing By Haplotype-Sharing Methods Applicable To Whole-Genome Analysis, Ilja M. Nolte, Andre R. De Vries, Geert T. Sijker, Ritsert C. Jansen, Dumitru Brinza, Alexander Zelikovskiy, Gerard J. Te Meerman

Computer Science Faculty Publications

We propose two new haplotype-sharing methods for identifying disease loci: the haplotype sharing statistic (HSS), which compares length of shared haplotypes between cases and controls, and the CROSS test, which tests whether a case and a control haplotype show less sharing than two random haplotypes. The significance of the HSS is determined using a variance estimate from the theory of U-statistics, whereas the significance of the CROSS test is estimated from a sequential randomization procedure. Both methods are fast and hence practical, even for whole-genome screens with high marker densities. We analyzed data sets of Problems 2 and 3 of …

Prevention Of Poxvirus Infection By Tetrapyrroles, Avril Rm Chen-Collins, Dabney W. Dixon, Andrei N. Vzorov, Luigi G. Marzilli, Richard W. Compans

Chemistry Faculty Publications

Background: Prevention of poxvirus infection is a topic of great current interest. We report inhibition of vaccinia virus in cell culture by porphyrins and phthalocyanines. Most previous work on the inhibition of viruses with tetrapyrroles has involved photodynamic mechanisms. The current study, however, investigates light-independent inhibition activity.

Methods: The Western Reserve (WR) and International Health Department-J (IHD-J) strains of vaccinia virus were used. Virucidal and antiviral activities as well as the cytotoxicity of test compounds were determined.

Results: Examples of active compounds include zinc protoporphyrin, copper hematoporphyrin, meso(2,6-dihydroxyphenyl)porphyrin, the sulfonated tetra-1-naphthyl and tetra-1- anthracenylporphyrins, selected sulfonated derivatives of halogenated tetraphenyl …