Lateral flow tests (LFTs) are an ingenious format for rapid and easy-to-use diagnostics, but they are fundamentally limited to assay chemistries that can be reduced to a single chemical step. In contrast, most laboratory diagnostic assays rely on multiple timed steps carried out by a human or a machine. Here, ...

The seasonal and spatial diversity of picocyanobacteria (Pcy) in lakes of the Great Mazurian Lakes (GLM) system was examined by DGGE analysis of molecular markers derived from the 16S–23S internal transcribed spacer (ITS) of the ribosomal operon and the phycocyanin operon (cpcBA-IGS). The study of nine lakes, ranging from mesotrophy ...

RATIONALE AND OBJECTIVES: Receiver operating characteristic (ROC) curves are ubiquitous in the analysis of imaging metrics as markers of both diagnosis and prognosis. While empirical estimation of ROC curves remains the most popular method, there are several reasons to consider smooth estimates based on a parametric model. MATERIALS AND METHODS: A ...

In diagnostic studies, we often need to combine several biomarkers to increase the diagnostic accuracy. For continuous-scaled biomarkers or diagnostic tests, it is often of interest to estimate the confidence interval for sensitivity at a fixed level of specificity. Despite the fact that there exist many literature reports on confidence ...

BACKGROUND: Applying a statistical method implies identifying underlying (model) assumptions and checking their validity in the particular context. One of these contexts is association modeling for epistasis detection. Here, depending on the technique used, violation of model assumptions may result in increased type I error, power loss, or biased parameter ...

RATIONALE AND OBJECTIVES: The estimation of the area under the receiver operating characteristic (ROC) curve (AUC) often relies on the assumption that the truly positive population tends to have higher marker results than the truly negative population. The authors propose a discriminatory measure to relax such an assumption and apply ...

In clinical research and practice, biomarkers help in understanding disease progression and are useful when monitoring patients and making treatment decisions. Correct quantification of biomarkers in predicting the clinical outcome is important for better treatment of individual patients. Despite the rich literature in statistical validation, application of these validation methods ...

OBJECTIVES: The CALIPER program recently established a comprehensive database of age- and sex-stratified pediatric reference intervals for 40 biochemical markers. However, this database was only directly applicable for Abbott ARCHITECT assays. We therefore sought to expand the applicability of this database to biochemical assays from other major manufacturers, allowing for ...

The use of ROC curves in evaluating a continuous or ordinal biomarker for the discrimination of two populations is commonplace. However, in many settings, marker measurements above or below a certain value cannot be obtained. In this paper, we study the construction of a smooth ROC curve (or surface in ...

Recalls and/or outbreaks associated with Salmonella contamination in peanut-containing products were reported over the past several years. There are very limited data available on the prevalence and concentration of Salmonella on raw shelled peanuts in the United States. The objectives of this study were to estimate the prevalence of Salmonella ...

Background: Calibration curves for use in chromatographic bioassays are normally constructed using least squares regression analysis. However, the effects of changes in the number and distribution of calibrators, together with the choice between linear and nonlinear regressions and their associated weighting factors, are difficult to quantify. Results/discussion: A Monte Carlo ...

Abstract Although manufacturers are compelled by the European IVD Directive, 98/79/EC, to have traceability of the values assigned to their calibrators if suitable higher order reference materials and/or procedures are available, there is still no equivalence of results for many measurands determined in clinical laboratories. The adoption of assays with ...

Untargeted metabolic profiling has become a common approach to attempt to understand biological systems. However, due to the large chemical diversity in the metabolites it is generally necessary to employ multiple analytical platforms so as to encompass a wide range of metabolites. Thus it is beneficial to find chemometrics approaches ...

The treatment of above-knee amputees with a prosthesis based on a socket is currently considered the standard clinical treatment. Nevertheless there are few investigations on mechanical loading conditions on these devices under realistic circumstances. Further insight in this matter might improve the design of sockets for everyday application. The presented ...

Genomic selection, a breeding method that promises to accelerate rates of genetic gain, requires dense, genome-wide marker data. Genotyping-by-sequencing can generate a large number of markers. However, without a reference genome, these markers are unordered and typically have a large proportion of missing data. Because marker imputation algorithms were developed ...

We previously demonstrated immune activation in the maternal peripheral circulation associated with preterm labor (PTL). There was an elevation in WBC mRNA of anti-inflammatory complement decay-accelerating factor (CD55) and the innate-immune response activating toll-like receptor 4 (TLR4). These findings suggested that collectively, these two molecules might serve as useful biomolecules ...

Measurement uncertainty is one of the most required parameters of analytical quality in environmental decision-making. Several approaches have been reported for estimating uncertainty in analytical measurements. The use of proficiency test (PT) is an alternative, not only for assessing the performance of individual analytical laboratories, but also for estimating the ...

Recently, genome wide DNA markers have been used in breeding value estimation of livestock species. The computational technique is known as genomic selection. Typically, a large number of marker effects are estimated from a small number of animals, which presents an under-determined problem. In this paper, we propose sparse marker ...

Although numerous diagnostic and/or prognostic biomarkers are proposed in the literature, only a limited number of them are finally used in daily practice. The necessary steps to prove their clinical interest include: 1) an exhaustive clinical and statistical evaluation demonstrating not only the added value of the marker with regard to ...

Francisella tularensis, the causative agent of tularemia, is commonly transmitted by ticks. To ensure accurate F. tularensis reporting rates in epidemiological surveys, specific discrimination between F. tularensis and Francisella-like tick endosymbionts (FLEs) is absolutely critical. Four molecular available techniques capable of distinguishing Francisella spp. were compared here for the first ...

The enhancement of human traits has received academic attention for decades, but only recently has moral enhancement using biomedical means - moral bioenhancement (MB) - entered the discussion. After explaining why we ought to take the possibility of MB seriously, the paper considers the shape and content of moral improvement, ...

When an existing standard marker does not have sufficient classification accuracy on its own, new markers are sought with the goal of yielding a combination with better performance. The primary criterion for selecting new markers is that they have good performance on their own and preferably be uncorrelated with the ...

Administration of biopharmaceutical products can generate immune response that may severely impact the safety or efficacy of the products. Immunogenicity evaluation, required by regulatory agencies, relies on well developed and validated assays. Key to such assay development is the determination of a cut point during assay validation. Although many methods ...

In this study, lead (Pb) bioaccessibility was assessed in peri-urban contaminated soils using a variety of established in vitro assays. Bioaccessibility data was then used to predict Pb relative bioavailability (RBA) using published in vivo-in vitro regression models in order to compare calculated estimates and measured values. Lead bioaccessibility varied ...

Template-guided intraoral surgery is attracting interest due to its accuracy and convenience. Usually, fiducial markers are used for registration of the different model coordinates for patients or plaster and fabrication coordinates in template-guided dental surgery. The accuracy of markers is important because it is directly related to the accuracy of ...

The recognition and discrimination of phytoplankton species is one of the foundations of freshwater biodiversity research and environmental monitoring. This step is frequently a bottleneck in the analytical chain from sampling to data analysis and subsequent environmental status evaluation. Here we present phytoplankton diversity data from 49 lakes including three ...

Reference ranges are a set of values that correctly include most of the subjects with characteristics similar to the reference group and exclude the others. When accurate, reference ranges aid physicians to interpret results of clinical measurements and thus establish diagnosis. However, obtaining accurate reference ranges is a very demanding ...

A three-factor, three-levels Box-Behnken design combined with response surface methodology (RSM) was used to optimize the photocatalytic degradation process of Methylene blue (MB), a cationic thiazin dye, using Agdoped TiO under UV irradiation in a batch reactor. The individual and interaction effects of three operational parameters, photocatalyst dose (1.5-2.5 g/L), initial ...

In composite interval mapping of quantitative trait loci (QTL), subsets of background markers are used to account for the effects of QTL outside the marker interval being tested. Here, I propose a QTL mapping approach (called G model) that utilizes genomewide markers as cofactors. The G model involves backward elimination ...

We propose a perceptual video coding framework based on the divisive normalization scheme, which was found to be an effective approach to model the perceptual sensitivity of biological vision, but has not been fully exploited in the context of video coding. At the macroblock (MB) level, we derive the normalization ...

We propose an integrated sampling, rarefaction, and extrapolation methodology to compare species richness of a set of communities based on samples of equal completeness (as measured by sample coverage) instead of equal size. Traditional rarefaction or extrapolation to equal-sized samples can misrepresent the relationships between the richnesses of the communities ...

Statistical validation of a surrogate endpoint or surrogate marker has been studied for three decades. However, there is still no consensus on how to evaluate surrogate endpoints or surrogate markers. There is much confusion on which method should be used for the evaluation of a surrogate endpoint or surrogate marker. ...

Animal distribution maps serve many purposes such as estimating transmission risk of zoonotic pathogens to both animals and humans. The reliability and usability of such maps is highly dependent on the quality of the input data. However, decisions on how to perform livestock surveys are often based on previous work ...

Kinematic models are commonly used to quantify foot and ankle kinematics, yet no marker sets or models have been proven reliable or accurate when wearing shoes. Further, the minimal detectable difference of a developed model is often not reported. We present a kinematic model that is reliable, accurate and sensitive ...

BACKGROUND: We wanted to determine whether specific, preanalytical sample handling increases preanalytical variation and bias test results compared with optimal handling. METHODS: Blood was collected into 4 serum-separation tubes from each arm of 60 outpatients. In 30 of the patients, half of the tubes were transported in the pneumatic tube ...

Discriminant analysis is commonly used to evaluate the ability of candidate biomarkers to separate patients into pre-defined groups. Recent extension of discriminant analysis to longitudinal data enables us to improve the classification accuracy based on biomarker profiles rather than on a single biomarker measurement. However, the biomarker measurement is often ...

BACKGROUND:Testosterone measurements that are accurate, reliable, and comparable across methodologies are crucial to improving public health. Current US Food and Drug Administration-cleared testosterone assays have important limitations. We sought to develop assay performance requirements on the basis of biological variation that allow physiologic changes to be distinguished from assay analytical ...

Multiple biomarkers are frequently observed or collected for detecting or understanding a disease. The research interest of this article is to extend tools of receiver operating characteristic (ROC) analysis from univariate marker setting to multivariate marker setting for evaluating predictive accuracy of biomarkers using a tree-based classification rule. Using an ...

Background: Over the past 20 years, an increased focus on detecting environmental chemicals posing a risk of adverse effects due to endocrine disruption has driven the creation of the U.S. EPA Endocrine Disruptor Screening Program (EDSP). Thousands of chemicals are subject to the EDSP, which could require millions of dollars ...

Summary This article considers receiver operating characteristic (ROC) analysis for bivariate marker measurements. The research interest is to extend tools and rules from univariate marker to bivariate marker setting for evaluating predictive accuracy of markers using a tree-based classification rule. Using an and-or classifier, an ROC function together with a ...

In order to optimize the management of genetic resources, in most cases a representative sample of the germplasm collections needs to be developed. The establishment of a core collection is thus of major importance either to minimize the cost associated with the management of the associated germplasm or to apply ...

ABSTRACT: BACKGROUND: Telomeres, the protective cap of chromosomes, have emerged as powerful markers of biological age and life history in model and non-model species. The qPCR method for telomere length estimation is one of the most common methods for telomere length estimation, but has received recent critique for being too ...

Accurate understanding of equipment tracking error is essential for decision making in image guided surgery. For tools tracked using markers attached to a rigid body, existing error estimation methods use the assumption that the individual marker errors are independent random variables. This assumption is not valid for all tracking systems. ...

The measurement of prompt gamma rays emitted from proton-induced nuclear reactions has been proposed as a method to verify in vivo the range of a clinical proton radiotherapy beam. A good understanding of the prompt gamma-ray emission during proton therapy is key to develop a clinically feasible technique, as it ...

OBJECTIVE: The mainstay of AA amyloidosis prevention and treatment is suppression of inflammation. In the present study we have tried to determine the efficacy of a variety of anti-inflammatory agents at suppressing AA amyloidosis in a mouse model of the disease. METHODS: AA amyloidosis was induced in Swiss male mice ...

The accuracy and precision of two new methods of model-based radiostereometric analysis (RSA) were hypothesised to be superior to a plain radiograph method in the assessment of polyethylene (PE) wear. A phantom device was constructed to simulate three-dimensional (3D) PE wear. Images were obtained consecutively for each simulated wear position ...

A linear model-based (MB) approach for the evaluation of Granger causality is compared to a nonlinear model-free (MF) one. The MB method is based on the identification of the coefficients of a multivariate linear regression via least-squares procedure. The MF technique is grounded on the concept of local prediction and ...

Self-diffusion in polymer solutions studied with pulsed-field gradient nuclear magnetic resonance (PFG NMR) is typically based either on a single self-diffusion coefficient, or a log-normal distribution of self-diffusion coefficients, or in some cases mixtures of these. Experimental data on polyethylene glycol (PEG) solutions and simulations were used to compare a ...

In this article, we review the key steps for the development of biosimilars and biobetters and related bioanalytical challenges, with a focus on how they are associated with immunogenicity. We analyze the factors that can impact antidrug antibody (ADA) responses and their correlations with preclinical and clinical outcomes to provide relevant ...

Abstract Background: Laboratory protocols used to calibrate commercial clinical chemistry systems affect test result quality. Mathematical models of system uncertainty can be developed using performance parameters provided by the manufacturer for various subsystems. These models can be used to evaluate protocols for specific laboratory operations. Methods: A mathematical model was ...