David Stenger

David Stenger
United States Naval Research Laboratory | NRL · Center for Biomolecular Science and Engineering

About

271
Publications
46,401
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7,705
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Publications

Publications (271)
Article
Full-text available
While tagging proteins and enzymes with metal affinity moieties is a common strategy to facilitate purification, such modifications can be detrimental towards the development of biological assays using nanomaterial reporter agents, especially in cases where such modifications are not indicated by vendors. Particularly, enzymes expressed with polyhi...
Article
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The design of minimum CRISPR RNA (crRNA) sets for detection of diverse RNA targets using sequence degeneracy has not been systematically addressed. We tested candidate degenerate Cas13a crRNA sets designed for detection of diverse RNA targets (Lassa virus). A decision tree machine learning (ML) algorithm (RuleFit) was applied to define the top attr...
Article
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Introduction In spite of promising medical, sociological, and engineering strategies and interventions to reduce the burden of disease, malaria remains a source of significant morbidity and mortality, especially among children in sub-Saharan Africa. In particular, progress in the development and administration of chemotherapeutic agents is threaten...
Article
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Strategies utilizing the CRISPR/Cas nucleases Cas13 and Cas12 have shown great promise in the development of highly sensitive and rapid diagnostic assays for the detection of pathogenic nucleic acids. The most common approaches utilizing fluorophore-quencher molecular beacons require strand amplification strategies or highly sensitive optical setup...
Article
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All CRISPR/CAS systems utilize CRISPR guide RNAs (crRNAs), the design of which depend on the type of CAS protein, genetic target and the environment/matrix. While machine learning approaches have recently been developed to optimize some crRNA designs, candidate crRNAs must still be screened for efficacy under relevant conditions. Here, we demonstra...
Article
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Background Malaria transmission-blocking vaccines (TBVs) could help break the cycle of malaria transmission by conferring community rather than individual protection. When introducing new intervention strategies, uptake is dependent on acceptability, not just efficacy. In this exploratory study on acceptability of TBVs in Sierra Leone, it was hypot...
Article
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Background Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive....
Article
The ability to easily produce or procure sequencing data has expanded to be within the reach of most clinics and research laboratories, but the complexity of sequence analysis remains a hurdle for many scientists, and a decline in sequencing cost means that the generation of gratuitous information in a given experiment is a challenge that is more a...
Article
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CRISPR-associated proteins that produce a signal in the presence of a target nucleic acid represent potentially powerful tools for diagnostics, but they also exhibit shortfalls that plague many CRISPR systems. For instance, not all targets elicit robust activity, which challenges the timely development of sensitive assays, and though many such test...
Preprint
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The electrochemical response of multilayer epitaxial graphene electrodes on silicon carbide substrates was studied for use as an electrochemical sensor for seawater samples spiked with environmental contaminants using cyclic square wave voltammetry. Results indicate that these graphene working electrodes are more robust and have lower background cu...
Article
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We demonstrate the viability of using ultra-thin sheets of microbially grown nanocellulose to build functional medical sensors. Microbially grown nanocellulose is an interesting alternative to plastics, as it is hydrophilic, biocompatible, porous, and hydrogen bonding, thereby allowing the potential development of new application routes. Exploiting...
Article
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Background: Malaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs),...
Preprint
Full-text available
Background Malaria parasites infect over 200 million people and cause more than 400,000 deaths each year. Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sen...
Preprint
Full-text available
Background. Malaria parasites infect over 200 million people and cause more than 400,000 deaths each year. Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally se...
Preprint
Full-text available
Background. Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive....
Poster
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Application of inexpensive, low SWaP (size, weight, and power), sensing devices as elements in a distributed sensing approach offers advantages over single point devices in early warning and offers insight into target distributions and plume movements. Our ongoing effort has focused on development of indicator arrays, hardware, software, and detect...
Article
We report the synthesis and characterization of highly air and temperature stable, solution-processed, n-type organic semiconductors: a perylene-diimide monomer and a perylene-diimide-based pendant polymer. When integrated into a transistor structure, both materials possess pure n-type transport with mobility as high as 10⁻⁵ cm² V⁻¹ s⁻¹ for the pol...
Article
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Background: This is the third paper in a 3-paper series evaluating alternative models for rapidly estimating neighborhood populations using limited survey data, augmented with aerial imagery. Methods: Bayesian methods were used to sample the large solution space of candidate regression models for estimating population density. Results: We accurat...
Article
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Electroanalytical techniques are useful for detection and identification because the instrumentation is simple and can support a wide variety of assays. One example is cyclic square wave voltammetry (CSWV), a practical detection technique for different classes of compounds including explosives, herbicides/pesticides, industrial compounds, and heavy...
Article
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We present the first demonstration of a fully-flexible, self-powered glucose indicator system that synergizes two flexible electronic technologies: a flexible self-powering unit in the form of a biofuel cell, with a flexible electronic device - a circuit-board decal fabricated with biocompatible microbial nanocellulose. Our proof-of-concept device,...
Article
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A large proportion of ongoing malaria parasite transmission is attributed to low-density subclinical infections not readily detected by available rapid diagnostic tests (RDTs) or microscopy. Plasmodium falciparum gametocyte carriage is subclinical, but gametocytemic individuals comprise the parasite reservoir that leads to infection of mosquitoes a...
Data
www.sciencetranslationalmedicine.org/cgi/content/full/11/473/eaan4479/DC1 Materials and Methods Fig. S1. The correlation of PAR and female gametocyte abundance per microliter of blood (based on pfs25 transcript number). Table S1. The complete list of P. falciparum proteins identified in the saliva from children with subclinical infection in Yaound...
Data
Table S5. Quantification of gametocytes per μl of blood in a subset (n = 100) of samples from Cameroon.
Technical Report
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This report is focused on a component of an effort intended to develop wireless sensor networks for real-time monitoring of airborne targets across a broad area. We have previously reported on two separate algorithms intended for identification of event occurrence. The goal of this report is to provide the detailed descriptions necessary for replic...
Article
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Febrile illnesses are among the most common reasons for visits to hospitals and clinics worldwide. Since fevers can arise from a wide range of diseases, identifying the causative pathogen is essential not only for effective personal treatment but also for early detection of outbreaks. The Defense Threat Reduction Agency (DTRA) tasked a coalition of...
Poster
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Reflectance based chemical and biological sensing enabled by COTS based hardware
Article
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Objective: The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg) among febrile individuals tested at Mercy Hospital Research Laboratory (MHRL) in Bo, Sierra Leone. Results: A total of 860 febrile individuals ages 5 years and older were tested by MHRL between July 2012 and June 2013 with a Standard Diagnosti...
Article
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We describe the use of a paper-based probe impregnated with a vanadium-containing polyoxometalate anion, [PMo11VO40]5-, on screen-printed carbon electrodes for the electrochemical determination of chlorate. Cyclic voltammetry (CV) and chronocoulometry were used to characterize the ClO₃- response in a pH = 2.5 solution of 100 mM sodium acetate. A li...
Patent
Systems and methods are provided for identification of a detection event relevant in applications focused on real-time or near real-time reporting in a continuous monitoring application. A controller collects data from a plurality of sensors and compares recent data to background data to determine whether an event has occurred. A system in accordan...
Poster
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Our ongoing efforts are focused on development of sensor systems intended to provide long term, autonomous, chemical threat monitoring in a distributed format. Here, we demonstrate the potential for detection of chemical and biological targets using a prototype reflectance sensor based on the TAOS TCS3200 RGB sensor chip. Chemical detection is acco...
Article
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Objective: The goal of this study was to examine the prevalence of HIV among febrile patients seeking care in Mercy Hospital, Bo, Sierra Leone, in 2012–2013. Results: A total of 1207 febrile persons were tested for HIV with Determine™ and SD Bioline rapid diagnostic tests kits that detect the presence of HIV antibodies and HIV p24 antigens. The ov...
Article
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Malaria remains a significant cause of morbidity and mortality in West Africa, but the contribution of other vectorborne infections (VBIs) to the burden of disease has been understudied. We used rapid diagnostic tests (RDTs) for three VBIs to test blood samples from 1795 febrile residents of Bo City, Sierra Leone, over a one-year period in 2012-201...
Article
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We report a simple and inexpensive electrochemical assay using a custom built hand-held potentiostat for the identification of explosives. The assay is based on a wipe test and is specifically designed for use in the field. The prototype instrument designed to run the assay is capable of performing time-resolved electrochemical measurements includi...
Article
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Here, the potential of colorimetric sensors utilizing porphyrin indicators for long term environmental monitoring is demonstrated. Prototype devices based on commercial color sensing chips (six per device) were combined with in-house developed algorithms for data analysis. The devices are intended to provide real-time sensing of threats. An initial...
Article
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We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have...
Article
Objectives: To examine the diversity of the health-care providers in urban Bo, Sierra Leone, identify the types of health-care facilities preferred by women for fevers, and analyze the road network distances from homes to preferred health-care providers. Methods: A population-based random sampling method was used to recruit 2419 women from Bo. A ge...
Article
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Here, we describe our efforts focused on development of an algorithm for identification of detection events in a real-time sensing application relying on reporting of color values using commercially available color sensing chips. The effort focuses on the identification of event occurrence, rather than target identification, and utilizes approaches...
Presentation
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Background Infectious diseases contribute to a high burden of diseases globally. Surveillance using low-cost technology, combined with cutting edge platforms offers a path for understanding the disease ecology of locations of interest in resource-poor countries. Our goal was to pilot a bio surveillance system comprising of rapid lateral flow immuno...
Article
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Citrobacter freundii is a Gram-negative opportunistic pathogen that is increasingly being recognized as a causative agent of hospital-acquired urinary tract infections and an important reservoir of antimicrobial resistance determinants. In this report, we describe the finished genome sequence of C. freundii strain SL151, a highly multidrug-resistan...
Article
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A collection of 74 Enterobacteriaceae isolated in Bo, Sierra Leone were tested for quinolone 23 antibiotic susceptibility and resistance mechanisms. The majority of isolates (62%) were resistant to quinolones and 61% harbored chromosomal gyrA and/or parC mutations. Plasmid-mediated quinolone resistance genes were ubiquitous with qnrB and aac(6´)-Ib...
Article
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Using square wave voltammetry, we show an increase in the electrochemical detection of trinitrotoluene (TNT) with a working electrode constructed from plasma modified graphene on a SiC surface vs. unmodified graphene. The graphene surface was chemically modified using electron beam generated plasmas produced in oxygen or nitrogen containing backgro...
Article
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This study used two types of paper supported materials with a prototype, reflectance-based detector for indication of hydrogen peroxide vapor under ambient laboratory conditions. Titanyl based indicators provide detection through reaction of the indicator resulting in a dosimeter type sensor, while porphyrin based indicators provide a reversible in...
Article
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Background The rising level of antimicrobial resistance among bacterial pathogens is one of the most significant public health problems globally. While the antibiotic resistance of clinically important bacteria is closely tracked in many developed countries, the types and levels of resistance and multidrug resistance (MDR) among pathogens currently...
Article
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Introduction: by passing refers to a person's decision to seek care at a healthcare facility that is not the nearest one of its type to the person's home. Methods: this study examined inpatient care facility bypassing in urban Bo, Sierra Leone using data from 1,980 women with children 15 years of age and younger who were interviewed in 2010-2011....
Article
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Background: This analysis examined how the proportion of children less than 5-years-old who slept under a bed net the previous night changed during and after a national long-lasting insecticidal net (LLIN) distribution campaign in Sierra Leone in November-December 2010. Methods: A citywide cross-sectional study in 2010-2011 interviewed the careg...
Presentation
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Technology update: Development status for miniaturized, distributed sensors
Article
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We report on the development of an electrochemical probe for the trace analysis of 2,4,6-trinitrotoluene (TNT) in soil samples. The probe is a combination of graphite electrodes, filter paper, with ethylene glycol and choline chloride as the solvent/electrolyte. Square wave chromatovoltammograms show the probes have a sensitivity for TNT of 0.75 nA...
Article
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There is a need for better estimators of population size in places that have undergone rapid growth and where collection of census data is difficult. We explored simulated estimates of urban population based on survey data from Bo, Sierra Leone, using two approaches: (1) stratified sampling from across 20 neighborhoods and (2) stratified single-sta...
Article
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Laboratories associated with small hospitals often have limited expertise, personnel, and equipment to rapidly identify rare and emerging infectious diseases. We describe the successful use of the FilmArray system for rapid detection of Ebola virus directly from clinical samples in 6 out of 83 tested subjects in a small health care center in Sierra...
Presentation
Full-text available
This effort demonstrates the potential for detection of chemical and biological targets using a prototype reflectance sensor based on the TAOS TCS3200 RGB sensor chip. Chemical detection is accomplished through measurement of changes in the reflectance of an array of porphyrin indicators. While each of the individual indicators provides only semi-s...
Article
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Lassa virus (LASV) is endemic to parts of West Africa and causes highly fatal hemorrhagic fever. The multimammate rat (Mastomys natalensis) is the only known reservoir of LASV. Most human infections result from zoonotic transmission. The very diverse LASV genome has 4 major lineages associated with different geographic locations. We used reverse tr...
Data
Rodent trapping procedures; coordinates of sampling locations; and list of all analyzed samples.
Patent
Full-text available
An apparatus having within or as part of a housing; a sample port; a microarray port; a lysis module; a purification module for containing a solid phase for binding of oligonucleotides; a thermocycling module for containing a polymerase chain reaction; a fragmentation module; and a microarray module for holding a microarray and a liquid in contact...
Article
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Background The purpose of this study was to examine malaria testing practices and preferences in Bo, Sierra Leone, and to ascertain interest in and willingness to take a home-based rapid diagnostic test administered by a community health volunteer (CHV) or a trained family member rather than travelling to a clinical facility for laboratory-based te...
Article
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Purpose: The purpose of this study was to conduct syndromic surveillance for important veterinary diseases in Koinadugu district, Northern Province, Sierra Leone. Methods: This study examined all veterinary syndromic surveillance reports submitted to the district veterinary office from January 2011 through December 2012. Results: In total, 5679 cas...
Article
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Square wave voltammetry for the reduction of 2,4,6-trinitrotoluene (TNT) was measured in 100 mM potassium phosphate buffer (pH 8) at gold electrodes modified with self-assembled monolayers (SAMs) containing either an alkane thiol or aromatic ring thiol structures. At 15 Hz, the electrochemical sensitivity (µA/ppm) was similar for all SAMs tested. H...
Article
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This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For fi...
Article
[Correspondence] Paul Drain and colleagues proposed a standard set of criteria to assess the diagnostic accuracy, clinical effect, and costs of point-of-care (POC) tests in low-income countries (LICs). We agree with the authors on the need to improve access to rapid diagnostics in LICs, and we add several factors based on our own research on POC te...
Article
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This effort seeks to evaluate the potential of the TAOS TCS3200 RGB sensor chip in a reflectance configuration for use in target detection based on color changes in porphyrin indicators using alcohols as model targets. The chip was evaluated as provided by Parallax, Inc as a component of the TCS3200-DB which includes white LEDs, collimator lens, an...
Article
[Summary] An outbreak of Ebola began in December 2013 in Guinea. Containment of this epidemic will require regionally-supported and globally-supported public health and medical responses. As researchers working in Sierra Leone, we have several suggestions for priority actions. First, access to diagnostic techniques should increase. Second, infectio...