Mathematics Commons^™

Linear Operators That Preserve Graphical Properties Of Matrices: Isolation Numbers, Leroy B. Beasley, Seok-Zun Song, Young Bae Jun

Mathematics and Statistics Faculty Publications

Let A be a Boolean {0, 1} matrix. The isolation number of A is the maximum number of ones in A such that no two are in any row or any column (that is they are independent), and no two are in a 2 × 2 submatrix of all ones. The isolation number of A is a lower bound on the Boolean rank of A. A linear operator on the set of m × n Boolean matrices is a mapping which is additive and maps the zero matrix, O, to itself. A mapping strongly preserves a set, S, if it …

Prognostic Value Of Elevated Serum Ceruloplasmin Levels In Patients With Heart Failure, Muhammad Hammadah, Yiying Fan, Yuping Wu, Stanley L. Hazen, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

Background: Ceruloplasmin (Cp) is a copper-binding acute-phase protein that is increased in inflammatory states and deficient in Wilson's disease. Recent studies demonstrate that increased levels of Cp are associated with increased risk of developing heart failure. Our objective was to test the hypothesis that serum Cp provides incremental and independent prediction of survival in stable patients with heart failure. Methods and Results: We measured serum Cp levels in 890 patients with stable heart failure undergoing elective cardiac evaluation that included coronary angiography. We examined the role of Cp levels in predicting survival over 5 years of follow-up. Mean Cp level …

Prognostic Value Of Elevated Levels Of Intestinal Microbe-Generated Metabolite Trimethylamine-N-Oxide In Patients With Heart Failure: Refining The Gut Hypothesis, W.H. Wilson Tang, Zeneng Wang, Yiying Fan, Bruce Levison, Jennie E. Hazen, Lillian M. Donahue, Yuping Wu, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background: Altered intestinal function is prevalent in patients with heart failure (HF), but its role in adverse outcomes is unclear. Objectives: This study investigated the potential pathophysiological contributions of intestinal microbiota in HF. Methods: We examined the relationship between fasting plasma trimethylamine-N-oxide (TMAO) and all-cause mortality over a 5-year follow-up in 720 patients with stable HF. Results:The median TMAO level was 5.0 μM, which was higher than in subjects without HF (3.5 μM; p < 0.001). There was modest but significant correlation between TMAO concentrations and B-type natriuretic peptide (BNP) levels (r = 0.23; p < 0.001). Higher plasma TMAO levels were associated with a 3.4-fold increased mortality risk. Following adjustments for traditional risk factors and BNP levels, elevated TMAO levels remained predictive of 5-year mortality risk (hazard ratio [HR]: 2.2; 95% CI: 1.42 to 3.43; p < 0.001), as well as following the addition of estimated glomerular filtration rate to the model (HR: 1.75; 95% CI: 1.07 to 2.86; p < 0.001). Conclusions: High TMAO levels were observed in patients with HF, and elevated TMAO levels portended higher long-term mortality risk independent of traditional risk factors and cardiorenal indexes.

Γ-Butyrobetaine Is A Proatherogenic Intermediate In Gut Microbial Metabolism Of L-Carnitine To Tmao, Robert A. Koeth, Bruce S. Levison, Miranda K. Culley, Jennifer A. Buffa, Zeneng Wang, Jill C. Gregory, Elin Org, Yuping Wu, Lin Li, Jonathan D. Smith, W.H. Wilson Tang, Joseph A. Didonato, Aldons J. Lusis, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

L-carnitine, a nutrient in red meat, was recently reported to accelerate atherosclerosis via a metaorganismal pathway involving gut microbial trimethylamine (TMA) formation and host hepatic conversion into trimethylamine-N-oxide (TMAO). Herein, we show that following L-carnitine ingestion, γ-butyrobetaine (γBB) is produced as an intermediary metabolite by gut microbes at a site anatomically proximal to and at a rate ∼1,000-fold higher than the formation of TMA. Moreover, we show that γBB is the major gut microbial metabolite formed from dietary L-carnitine in mice, is converted into TMA and TMAO in a gut microbiota-dependent manner (like dietary L-carnitine), and accelerates atherosclerosis. Gut microbial …

Prognostic Value Of Estimated Functional Capacity Incremental To Cardiac Biomarkers In Stable Cardiac Patients, W.H. Wilson Tang, Eric J. Topol, Yiying Fan, Yuping Wu, Leslie Cho, Cindy Stevenson, Stephen G. Ellis, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background: Few studies have investigated functional capacity self-assessment tools in either prediction of future major adverse cardiac outcomes beyond all-cause mortality or direct comparisons with clinically available biomarkers. Methods and Results: We estimated functional capacity using the Duke Activity Status Index (DASI) questionnaire in 8987 sequential stable patients without acute coronary syndrome who were undergoing elective diagnostic coronary angiography with 3-year follow-up of major adverse cardiac events (death, nonfatal myocardial infarction, or stroke). A low DASI score provided independent prediction of a 4.8-fold increase in future risk of incident major adverse cardiac events at 3 years (quartiles 1 versus 4 …

Diagnosis Of Infection After Splenectomy For Trauma Should Be Based On Lack Of Platelets Rather Than White Blood Cell Count, Aman Banerjee, Katherine B. Kelly, Hannah Y. Zhou, Shanteria D. Dixon, Ariadni Papana Dagiasis, Linda M. Quinn, Jeffrey A. Claridge

Mathematics and Statistics Faculty Publications

Background: There is a lack of evidence-based criteria to assist the diagnosis of infection following trauma splenectomy (TS). However, the literature suggests that white blood cell count (WBC) is associated with infection in patients who undergo TS. We sought to find whether there exist key differences in laboratory and clinical parameters that can assist the diagnosis of infection after TS. Methods: We evaluated all consecutive trauma patients who had undergone TS at a Level 1 trauma center from 2005 to 2011 for the development of infection. To do this, we compared the values of demographic, laboratory, and clinical variables of …

Synergistic Effects Of 3d Ecm And Chemogradients On Neurite Outgrowth And Guidance: A Simple Modeling And Microfluidic Framework, Parthasarathy Srinivasan, Ioannis K. Zervantonakis, Chandrasekhar R. Kothapalli

Mathematics and Statistics Faculty Publications

During nervous system development, numerous cues within the extracellular matrix microenvironment (ECM) guide the growing neurites along specific pathways to reach their intended targets. Neurite motility is controlled by extracellular signal sensing through the growth cone at the neurite tip, including chemoattractive and repulsive cues. However, it is difficult to regenerate and restore neurite tracts, lost or degraded due to an injury or disease, in the adult central nervous system. Thus, it is important to evaluate the dynamic interplay between ECM and the concentration gradients of these cues, which would elicit robust neuritogenesis. Such information is critical in understanding the …

On The Structure Of Co-Kähler Manifolds, Giovanni Bazzoni, John Oprea

Mathematics and Statistics Faculty Publications

By the work of Li, a compact co-Kähler manifold M is a mapping torus Kφ, where K is a Kähler manifold and φ is a Hermitian isometry. We show here that there is always a finite cyclic cover M¯¯¯¯¯ of the form M¯¯¯¯¯≅K×S1, where ≅ is equivariant diffeomorphism with respect to an action of S1 on M and the action of S1 on K×S1 by translation on the second factor. Furthermore, the covering transformations act diagonally on S1,K and are translations on the S1 factor. In this way, we see that, up to a finite cover, all compact co-Kähler manifolds …

Prognostic Value Of Choline And Betaine Depends On Intestinal Microbiota-Generated Metabolite Trimethylamine-N-Oxide, Zeneng Wang, W.H. Wilson Tang, Jennifer A. Buffa, Xiaoming Fu, Earl B. Britt, Robert A. Koeth, Bruce S. Levison, Yiying Fan, Yuping Wu, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Aims: Recent metabolomics and animal model studies show trimethylamine-N-oxide (TMAO), an intestinal microbiota-dependent metabolite formed from dietary trimethylamine-containing nutrients such as phosphatidylcholine (PC), choline, and carnitine, is linked to coronary artery disease pathogenesis. Our aim was to examine the prognostic value of systemic choline and betaine levels in stable cardiac patients. Methods and Results: We examined the relationship between fasting plasma choline and betaine levels and risk of major adverse cardiac events (MACE = death, myocardial infraction, stroke) in relation to TMAO over 3 years of follow-up in 3903 sequential stable subjects undergoing elective diagnostic coronary angiography. In our study …

Plasma Ceruloplasmin, A Regulator Of Nitric Oxide Activity, And Incident Cardiovascular Risk In Patients With Ckd, David J. Kennedy, Yiying Fan, Yuping Wu, Michael Pepoy, Stanley L. Hazen, W.H. Wilson Tang

Mathematics and Statistics Faculty Publications

Background and objectives: Increased serum levels of the acute-phase reactant ceruloplasmin predict adverse clinical outcomes in the setting of acute coronary syndromes and heart failure, but their role in patients with CKD is unclear. This study investigated the relationship of ceruloplasmin with clinical outcomes in CKD, especially with regard to traditional cardiac biomarkers. Design, setting, participants, & measurements: Serum ceruloplasmin levels in consecutive study participants with CKD (n=654; estimated GFR<60 ml/min per 1.73 m2) as well as a control group of non-CKD participants matched for age and sex (n=250) were measured. Study participants were enrolled during 2001–2006 from a population of patients presenting for elective diagnostic coronary angiography and prospectively followed for 3 years (median follow-up=1095 days) to determine incident major adverse cardiac events (defined as a composite of death, nonfatal myocardial infarction, and stroke). Results: Serum ceruloplasmin levels in CKD patients were elevated versus controls (median [interquartile range]; 25.5 [21.8–29.6] versus 22.7 [19.7–26.5] mg/dl; P<0.001) and associated with increased risk of future major adverse cardiac events (hazard ratio, 1.35; 95% confidence interval, 1.0 to 1.82; P=0.04). After adjusting for traditional risk factors, higher serum ceruloplasmin was still associated with higher risk of major adverse cardiac events at 3 years (hazard ratio, 1.61; 95% confidence interval, 1.15 to 2.25; P=0.01). Conclusion: In CKD patients, increased serum ceruloplasmin, a regulator of nitric oxide activity, is associated with increased risk of long-term adverse cardiovascular events, even after multivariable model adjustment for traditional clinical and biologic risk factors.

An Abundant Dysfunctional Apolipoprotein A1 In Human Atheroma, Ying Huang, Joseph A. Didonato, Bruce S. Levison, Dave Schmitt, Lin Li, Yuping Wu, Jennifer Buffa, Timothy Kim, Gary S. Gerstenecker, Xiaodong Gu, Chandra S. Kadiyala, Zeneng Wang, Miranda K. Culley, Jennie E. Hazen, Anthony J. Didonato, Xiaoming Fu, Stela Z. Berisha, Daoquan Peng, Truc T. Nguyen, Shaohong Liang, Chia-Chi Chuang, Leslie Cho, Edward F. Plow, Paul L. Fox, Valentin Gogonea, W.H. Wilson Tang, John S. Parks, Edward A. Fisher, Jonathan D. Smith, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Recent studies have indicated that high-density lipoproteins (HDLs) and their major structural protein, apolipoprotein A1 (apoA1), recovered from human atheroma are dysfunctional and are extensively oxidized by myeloperoxidase (MPO). In vitro oxidation of either apoA1 or HDL particles by MPO impairs their cholesterol acceptor function. Here, using phage display affinity maturation, we developed a high-affinity monoclonal antibody that specifically recognizes both apoA1 and HDL that have been modified by the MPO-H2O2-Cl− system. An oxindolyl alanine (2-OH-Trp) moiety at Trp72 of apoA1 is the immunogenic epitope. Mutagenesis studies confirmed a critical role for apoA1 Trp72 in MPO-mediated inhibition of the ATP-binding …

Brain Control Of Functional Reach In Healthy Adults And Stroke Survivors, Janis J. Daly, Ken Hrovat, John Holcomb, Svetlana Pundik

Mathematics and Statistics Faculty Publications

Purpose: Recovery of the most basic shoulder-flexion/elbow-extension components of functional reach is critical for effective arm function following stroke. In order to understand the mechanisms of motor recovery, it is important to characterize the pattern of brain activation during the reach task. Methods: We evaluated 11 controls and 23 moderately to severely impaired chronic stroke survivors (>6 months), with impaired shoulder flexion and elbow extension. Measures were acquired for Arm Motor Ability Test (AMAT) and functional Magnetic Resonance Imaging (fMRI) during the basic shoulder/elbow reach. Results: First, in controls, lateralization of fMRI signal during the reach task was less …

Multi-Peak Solutions To Two Types Of Free Boundary Problems, Yi Li, Shuangjie Peng

Mathematics and Statistics Faculty Publications

We consider the existence of multi-peak solutions to two types of free boundary problems arising in confined plasma and steady vortex pair under conditions on the nonlinearity we believe to be almost optimal. Our results show that the “core” of the solution has multiple connected components, whose boundary called free boundary of the problems consists approximately of spheres which shrink to distinct single points as the parameter tends to zero.

Stability Of Traveling-Wave Solutions For A Schrodinger System With Power-Type Nonlinearities, Nghiem Nguyen, Rushun Tian, Zhi-Qiang Wang

Mathematics and Statistics Faculty Publications

In this article, we consider the Schrodinger system with powertype nonlinearities, (Formula presented) where j = 1,...,m, u_j are complex-valued functions of (x, t) 2 R^N+1, a, b are real numbers. It is shown that when b > 0, and a + (m - 1)b > 0, for a certain range of p, traveling-wave solutions of this system exist, and are orbitally stable.

A Shortcut For Multiple Testing On The Directed Acyclic Graph Of Gene Ontology, Garrett Saunders, John R. Stevens, S. Clay Isom

Mathematics and Statistics Faculty Publications

Background: Gene set testing has become an important analysis technique in high throughput microarray and next generation sequencing studies for uncovering patterns of differential expression of various biological processes. Often, the large number of gene sets that are tested simultaneously require some sort of multiplicity correction to account for the multiplicity effect. This work provides a substantial computational improvement to an existing familywise error rate controlling multiplicity approach (the Focus Level method) for gene set testing in high throughput microarray and next generation sequencing studies using Gene Ontology graphs, which we call the Short Focus Level.

Results: The Short Focus …

Correlation Properties Of Collective Motion In Bacterial Suspensions, Shawn D. Ryan, Andrey Sokolov, Leonid Berlyand, Igor S. Aranson

Mathematics and Statistics Faculty Publications

The study of collective motion in bacterial suspensions has been of significant recent interest. To better understand the non-trivial spatio-temporal correlations emerging in the course of collective swimming in suspensions of motile bacteria, a simple model is employed: a bacterium is represented as a force dipole with size, through the use of a short-range repelling potential, and shape. The model emphasizes two fundamental mechanisms: dipolar hydrodynamic interactions and short-range bacterial collisions. Using direct particle simulations validated by a dedicated experiment, we show that changing the swimming speed or concentration alters the time scale of sustained collective motion, consistent with experiment. …

Ct Angiography In The Detection Of Carotid Body Enlargement In Patients With Hypertension And Heart Failure, Sreejit Nair, Ajay Gupta, Marat Fudim, Christopher Robinson, Vinay Ravi, Sandra M. Hurtado Rua, Zoar Engelman, Kyungmouk S. Lee, C. Douglas Philips, Akhilesh K. Sista

Mathematics and Statistics Faculty Publications

Introduction: The carotid body (CB) has previously been found to be enlarged and hyperactive in various disease states such as heart failure (HF), hypertension (HTN), and respiratory disease. Evaluation of CB size in these disease states using imaging has not been performed. The purpose of this case–control study was to compare CB sizes in patients with HF and HTN with those of controls using CT angiography. Methods: A retrospective review was performed on 323 consecutive patients who had neck computed tomography angiography (CTA) exams in 2011. Following extensive review, 17 HF and HTN patients and 14 controls were identified. Two …

Function And Distribution Of Apolipoprotein A1 In The Artery Wall Are Markedly Distinct From Those In Plasma, Joseph A. Didonato, Ying Huang, Kulwant S. Aulak, Orli Even-Or, Gary Gerstenecker, Valentin Gogonea, Yuping Wu, Paul L. Fox, W.H. Wilson Tang, Edward F. Plow, Jonathan D. Smith, Edward A. Fisher, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background—Prior studies show that apolipoprotein A1 (apoA1) recovered from human atherosclerotic lesions is highly oxidized. Ex vivo oxidation of apoA1 or high-density lipoprotein (HDL) cross-links apoA1 and impairs lipid binding, cholesterol efflux, and lecithin-cholesterol acyltransferase activities of the lipoprotein. Remarkably, no studies to date directly quantify either the function or HDL particle distribution of apoA1 recovered from the human artery wall. Methods and Results—A monoclonal antibody (10G1.5) was developed that equally recognizes lipid-free and HDL-associated apoA1 in both native and oxidized forms. Examination of homogenates of atherosclerotic plaque–laden aorta showed >100-fold enrichment of apoA1 compared with normal aorta (P<0.001). Surprisingly, buoyant density fractionation revealed that only a minority (<3% of total) of apoA1 recovered from either lesions or normal aorta resides within an HDL-like particle (1.063≤d≤1.21). In contrast, the majority (>90%) …

Tetrathiomolybdate-Associated Copper Depletion Decreases Circulating Endothelial Progenitor Cells In Women With Breast Cancer At High Risk Of Relapse, S. Jain, J. Cohen, M. M. Ward, N. Kornhauser, E. Chuang, T. Cigler, A. Moore, D. Donovan, C. Lam, M. V. Cobham, S. Schneider, Sandra M. Hurtado Rua, S. Benkert, C. Mathijsen Greenwood, R. Zelkowitz, J. D. Warren, M. E. Lane, V. Mittal, S. Rafii, L. T. Vahdat

Mathematics and Statistics Faculty Publications

Background: Bone marrow-derived endothelial progenitor cells (EPCs) are critical for metastatic progression. This study explores the effect of tetrathiomolybdate (TM), an anti-angiogenic copper chelator, on EPCs in patients at high risk for breast cancer recurrence. Patients and methods: This phase 2 study enrolled breast cancer patients with stage 3 and stage 4 without evidence of disease (NED), and stage 2 if triple-negative. TM 100 mg orally was administered to maintain ceruloplasmin <17 mg/dl for 2 years or until relapse. The primary end point was change in EPCs. Results: Forty patients (28 stage 2/3, 12 stage 4 NED) were enrolled. Seventy-five percent patients achieved the copper depletion target by 1 month. Ninety-one percent of triple-negative patients copper-depleted compared with 41% luminal subtypes. In copper-depleted patients only, there was a significant reduction in EPCs/ml by 27 (P = 0.04). Six patients relapsed while on study, of which only one patient had EPCs maintained below baseline. The 10-month relapse-free survival was 85.0% (95% CI 74.6%–96.8%). Only grade 3/4 toxicity was hematologic: neutropenia (3.1% of cycles), febrile neutropenia (0.2%), and anemia (0.2%). Conclusions: TM is safe and appears to maintain EPCs below baseline in copper-depleted patients. TM may promote tumor dormancy and ultimately prevent relapse.

Topological Complexity Of H-Spaces, Gregory Lupton, Jerome Scherer

Mathematics and Statistics Faculty Publications

Let X be a (not-necessarily homotopy-associative) H-space. We show that TCn+1(X) = cat (Xn), forn≥1, where TCn+1(−) denotes the so-called higher topological complexity introduced by Rudyak, and cat (−) denotes the Lusternik-Schnirelmann category. We also generalize this equality to an inequality, which gives an upper bound for TCn+1(X), in the setting of a space Y acting on X.

A New Optimization Algorithm For Single Hidden Layer Feedforward Neural Networks, Leong Kwan Li, Sally Shao, Ka-Fai Cedric Yiu

Mathematics and Statistics Faculty Publications

Feedforward neural networks are the most commonly used function approximation techniques in neural networks. By the universal approximation theorem, it is clear that a single-hidden layer feedforward neural network (FNN) is sufficient to approximate the corresponding desired outputs arbitrarily close. Some researchers use genetic algorithms (GAs) to explore the global optimal solution of the FNN structure. However, it is rather time consuming to use GA for the training of FNN. In this paper, we propose a new optimization algorithm for a single-hidden layer FNN. The method is based on the convex combination algorithm for massaging information in the hidden layer. …

Detectable Subclinical Myocardial Necrosis Is Associated With Cardiovascular Risk In Stable Patients With Diabetes, W.H. Wilson Tang, Yuping Wu, Earl B. Britt Jr., Naveed Iqbal, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

OBJECTIVE: To investigate the relationship between different degrees of subclinical myocardial necrosis, glycemic control, and long-term adverse clinical outcomes within a stable patient population with diabetes mellitus. RESEARCH DESIGN AND METHODS: We examined 1,275 stable patients with diabetes mellitus undergoing elective diagnostic coronary angiography with cardiac troponin I (cTnI) levels below the diagnostic cut-off for defining myocardial infarction (MI) (<0.03 ng/mL). The relationship of subclinical myocardial necrosis (cTnI 0.009–0.029 ng/mL) with incident major adverse cardiovascular events (MACE; defined as any death, MI, or stroke) over 3 years of follow-up was examined. RESULTS: Subclinical myocardial necrosis was observed in 22% of patients. A strong association was observed between the magnitude of subclinical myocardial necrosis and risk of 3-year incident MACE (hazard ratio, 1.98; 95% confidence interval, 1.48–2.65; P < 0.001) and remained statistically significant even after adjustment for traditional risk factors, high-sensitivity C-reactive protein, and creatinine clearance. Only a weak correlation was observed between the presence of subclinical myocardial necrosis and either glycemic control (r = 0.06; P = 0.044 for hemoglobin A1c versus cTnI) or insulin resistance (r = 0.04; P = 0.094 for glucose-to-insulin ratio versus cTnI). CONCLUSIONS: The presence of detectable subclinical myocardial necrosis in stable patients with diabetes mellitus is associated with heightened long-term risk for MACE, independent of traditional risk factors and glycemic control.

Single Exhaled Breath Metabolomic Analysis Identifies Unique Breathprint In Patients With Acute Decompensated Heart Failure, Michael A. Samara, W.H. Wilson Tang, Frank Cikach Jr., Zeynep Gul, Lily Tranchito, Kelly M. Paschke, Jamie Viterna, Yuping Wu, Daniel Laskowski, Raed A. Dweik

Mathematics and Statistics Faculty Publications

Acute decompensated heart failure (ADHF) is the most common indication for hospital admission, particularly in the elderly, yet the identification of those with impending decompensation using conventional clinical methods is unreliable and frequently leaves insufficient lag time for therapeutic interventions (1). Exhaled breath constitutes a complex mixture of hundreds of volatile organic compounds (VOCs) that could potentially be used as a safe and noninvasive method of diagnostic and therapeutic monitoring (2). Previous research studies have identified elevated acetone, pentane, and nitric oxide levels in exhaled breath in the setting of HF correlated with disease severity (3–5). Selected ion-flow tube mass-spectrometry …

Diminished Antioxidant Activity Of High-Density Lipoprotein–Associated Proteins In Chronic Kidney Disease, David J. Kennedy, W.H. Wilson Tang, Yiying Fan, Yuping Wu, Shirley Mann, Michael Pepoy, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Background:Decreased serum arylesterase activity, catalyzed by the high-density lipoprotein–associated paraoxonase (PON)-1, is associated with increased oxidant stress and atherosclerosis risk. We sought to determine the prognostic value of serum PON-1 activity, as monitored by PON or arylesterase activities, in subjects with chronic kidney disease (CKD), particularly in relation to established cardiac biomarkers.Methods and Results: Serum arylesterase and PON activities were measured in sequential subjects with CKD (n=630; estimated glomerular filtration rate [eGFR] <60 mL/min per 1.73 m2) and an age- and sex-matched control group of non-CKD subjects (n=315) presenting for cardiac evaluations and prospectively followed for incident (3-year) major adverse cardiac events (composite of death, nonfatal myocardial infarction, and stroke). Serum arylesterase activity in CKD subjects was lower compared with that in non-CKD control subjects [median (interquartile range) 94 (77 to 112) versus 103 (85 to 121) μmol(L·min) per mL, P<0.001]; similarly, PON activity in CKD subjects was lower compared with that in non-CKD control subjects [median (interquartile range) 474 (275 to 936) versus 586 (301 to 1118) nmol(L·min) per mL, P<0.001]. Lower serum arylesterase (hazard ratio 1.8, 95% CI 1.26 to 2.57, P<0.01) was a predictor of poorer outcomes. After adjusting for traditional risk factors and medication use, lower serum arylesterase (hazard ratio 1.55, 95% CI 1.08 to 2.23, P<0.05) still conferred an increased risk of major adverse cardiac events at 3 years. Conclusions: In patients with CKD, decreased serum arylesterase activity, a measure of diminished antioxidant properties of PON-1, predicts higher risk of incident long-term adverse cardiovascular events (heart attack, stroke, or death) in multivariable models adjusting for established clinical and biochemical risk factors.

Enhanced Surveillance On Food-Borne Disease Outbreaks: Dynamics Of Cross-Contamination In Biocidal Wash Procedure, Daniel Munther, Jianhong Wu

Mathematics and Statistics Faculty Publications

Understanding the geographic and temporal spread of food-borne diseases associated with fresh produce is crucial for informing adequate surveillance and control. As a first step towards this goal, we develop and analyze a novel three stage model at the processing/sanitization juncture in the fresh produce supply chain. The key feature of our model is its ability to describe the dynamics of cross-contamination during commercial wash procedures. In general, we quantify the degree of cross-contamination in terms of model parameters. Applying these results in the case of Escherichia coli O157:H7 contamination of fresh-cut romaine lettuce, we identify the mean wash time …

Anterior Abdominal Stab Injury: A Comparison Of Self-Inflicted And Intentional Third-Party Stabbings, Aman Banerjee, Hannah Y. Zhou, Katherine B. Kelly, Bianca D. Downs, John J. Como, Jeffrey A. Claridge

Mathematics and Statistics Faculty Publications

Background: There is minimal literature comparing self-inflicted (SI) with non–self-inflicted (NSI) anterior abdominal stab wounds (AASW). Methods: Adult patients treated at a level 1 trauma center from 2006 through 2011 with an AASW were reviewed. Results: There were 215 patients with an AASW; 20% were SI. NSI patients had more nonabdominal injuries (47% vs 16%, P < .01) and disposition directly to the operating room (45% vs 26%, P = .02). Intra-abdominal injury rates were similar. One hundred twenty-eight patients had isolated AASWs; 28% were SI. SI patients had higher admission rates (86% vs 63%, P = .01). One hundred three patients had isolated stable/asymptomatic AASWs; 31% were SI. SI patients had more admissions (84% vs 52%, P < .01), had higher intensive care unit admission rates (23% vs 5%, P = .01), longer LOS (3.2 vs 1.4, P < .01), and higher hospital charges ($18,000 vs $11,000, P < .01). The rates of intra-abdominal injury were again similar. Conclusions: Controlling for extra-abdominal injuries, SI AASW patients have similar rates of intra-abdominal injury but use more resources.

Toric Complete Intersection Codes, Ivan Soprunov

Mathematics and Statistics Faculty Publications

In this paper we construct evaluation codes on zero-dimensional complete intersections in toric varieties and give lower bounds for their minimum distance. This generalizes the results of Gold–Little–Schenck and Ballico–Fontanari who considered evaluation codes on complete intersections in the projective space.

The Ideal Free Strategy With Weak Allee Effect, Daniel Munther

Mathematics and Statistics Faculty Publications

This paper examines the interplay between optimal movement strategies and the weak Allee effect within the context of two competing species in a spatially heterogenous environment. When both species have the same populations dynamics, previous studies identified an ‘ideal free’ strategy which is able to exclude any other competitor playing a ‘non-ideal free’ strategy. We find that if the ideal free disperser is subject to a weak Allee effect, a competing species utilizing very weak or very strong advection will still be excluded despite having superior population dynamics. However, for intermediate advection rates, such a competitor can invade the ideal …

Usefulness Of Cardiac Biomarker Score For Risk Stratification In Stable Patients Undergoing Elective Cardiac Evaluation Across Glycemic Status, W.H. Wilson Tang, Naveed Iqbal, Yuping Wu, Stanley L. Hazen

Mathematics and Statistics Faculty Publications

Several clinically available cardiac biomarkers have established their prognostic value in patients with acute coronary syndromes. However, their relative prognostic significance in stable subjects has not been prospectively validated, either individually or in combination. The aim of this study was to evaluate the extent to which B-type natriuretic peptide, myeloperoxidase, and high-sensitivity C-reactive protein alone or together could be prognostic biomarkers in 3,635 consecutive stable patients without acute coronary syndrome who underwent elective diagnostic coronary angiography. After adjusting for traditional risk factors and renal function, each of the markers monitored was a significant predictor of incident major adverse cardiovascular events …

Some Minor-Closed Classes Of Signed Graphs, Dan Slilaty, Xiangqian Zhou

Mathematics and Statistics Faculty Publications

We define four minor-closed classes of signed graphs in terms of embeddability in the annulus, projective plane, torus, and Klein bottle. We give the full list of 20 excluded minors for the smallest class and make a conjecture about the largest class.