Problem Of Quantification Research Articles

Approach to Lamb Wave Lateral Crack Quantification in Elastic Plate Based on Reflection and Transmission Coefficients Surfaces

Ultrasonic guided wave is promising in structure integrity management, but there is still much to learn about it because of its complex mechanism. Defect sizing or quantification is very important for structure inspection using ultrasonic guided waves, and this inverse problem is also very difficult to solve. The work presented in this article aims to resolve the lateral crack quantification problem in the inspection of thin elastic plate using Lamb wave. First, two-dimensional (2D) boundary element method (BEM) simulation was used to study the interaction of one chosen pure mode Lamb wave with lateral crack defect, and this could be defined as the forward problem. Then reflection and transmission coefficients surfaces were built from the results of the numerical simulation. Finally, an approach for lateral crack quantification based on these reflection and transmission coefficients surfaces was proposed. The quantification examples show that the presented approach gives acceptable accuracy. Some limitations of this approach are also discussed.

Importance of HPLC confirmation of problematic carbohydrate-deficient transferrin (CDT) results from a multicapillary electrophoresis routine method

Background This study presents results from a routine laboratory setup for carbohydrate-deficient transferrin (CDT) measurement, using initial capillary electrophoresis (CE) analysis and, in problematic cases, further investigation by high-performance liquid chromatography (HPLC). Methods CDT by the Capillarys CDT assay (disialo- and asialotransferrin) was measured on a Capillarys 2 multicapillary CE system (Sebia). In cases of abnormal peak profiles or other interferences in the electropherogram, samples were remeasured following sample cleanup by “Sample treatment” (Sebia). If the problems remained, or otherwise when confirmatory testing was considered important, samples were analysed by an HPLC candidate reference method. Results In about 0.6% of the routine specimens, reanalysis was performed after sample cleanup. Confirmatory HPLC analysis was needed in half of the cases. Quantification problems were observed for genetic transferrin variants and samples showing a variety of abnormal peak profiles. In these cases, HPLC analysis provided accurate quantification, or at least an estimation (positive/negative), of the CDT level. Confirmatory HPLC analysis was also important for evaluation of borderline values, because only part of those cases were indicated to be true positives. Conclusions These results indicated that a routine laboratory setup for CDT measurement, using initial high-throughput multicapillary CE analysis with a confirmatory HPLC analysis option, will combine rapid quantitative and qualitative workflow with enhanced patient safety.

Complementary chromatography separation combined with hydride generation–inductively coupled plasma mass spectrometry for arsenic speciation in human urine

This study aimed to establish complementary high performance liquid chromatography (HPLC) methods including three modes of separation: ion pairing, cation exchange, and anion exchange chromatography, with detection by inductively coupled plasma mass spectrometry (ICPMS). The ion pairing mode enabled the separation of inorganic arsenate (As(V)), monomethylarsonic acid (MMA(V)), and dimethylarsinic acid (DMA(V)). However, the ion pair mode was unable to differentiate inorganic arsenite (As(III)) from arsenobetaine (AsB); instead, cation exchange chromatography was used to isolate and quantify AsB. Anion exchange chromatography was able to speciate all of the aforementioned arsenic species. Potential inaccurate quantification problem with urine sample containing elevated concentration of AsB, which eluted immediately after As(III) in anion exchange or ion pairing mode, was overcame by introducing a post-column hydride generation (HG) derivatization step. Incorporating HG between HPLC and ICPMS improved sensitivity and specificity by differentiating AsB from hydride-forming arsenic species. This paper emphasizes the usefulness of complementary chromatographic separations in combination with HG–ICPMS to quantitatively determine concentrations of As(III), DMA(V), MMA(V), As(V), and AsB in the sub-microgram per liter range in human urine.

Algunos aspectos de la cuantificación de grado (con especial atención a la llamada "Cuantificación de grado verbal ")

Fecha de recepción: 26 de junio de 2009.Fecha de aceptación: 7 de mayo de 2010.En este artículo se hace, en primer lugar, un recorrido historiográfico por los estudios que se han dedicado a la cuantificación de grado. En este sentido, planteamos la posibilidad de distinguir entre grado e intensidad, sobre todo, y el análisis de la relación entre la cuantificación de grado y la aspectualidad (Aktionsart) de ciertas unidades léxicas. En una segunda parte de este artículo nos centramos en la idea de que, si bien la cuantificación de grado es aceptada por distintas unidades léxicas, no incide de la misma manera en todas ellas, sobre todo cuando el cuantificador de grado acompaña a un verbo.

Automatic Detection of Dominance and Expected Interest

Social Signal Processing is an emergent area of research that focuses on the analysis of social constructs. Dominance and interest are two of these social constructs. Dominance refers to the level of influence a person has in a conversation. Interest, when referred in terms of group interactions, can be defined as the degree of engagement that the members of a group collectively display during their interaction. In this paper, we argue that only using behavioral motion information, we are able to predict the interest of observers when looking at face-to-face interactions as well as the dominant people. First, we propose a simple set of movement-based features from body, face, and mouth activity in order to define a higher set of interaction indicators. The considered indicators are manually annotated by observers. Based on the opinions obtained, we define an automatic binary dominance detection problem and amulticlass interest quantification problem. Error-Correcting Output Codes framework is used to learn to rank the perceived observer's interest in face-to-face interactions meanwhile Adaboost is used to solve the dominant detection problem. The automatic system shows good correlation between the automatic categorization results and the manual ranking made by the observers in both dominance and interest detection problems.

Towards reliable isoform quantification using RNA-SEQ data

BackgroundIn eukaryotes, alternative splicing often generates multiple splice variants from a single gene. Here weexplore the use of RNA sequencing (RNA-Seq) datasets to address the isoform quantification problem. Given a set of known splice variants, the goal is to estimate the relative abundance of the individual variants.MethodsOur method employs a linear models framework to estimate the ratios of known isoforms in a sample. A key feature of our method is that it takes into account the non-uniformity of RNA-Seq read positions along the targeted transcripts.ResultsPreliminary tests indicate that the model performs well on both simulated and real data. In two publicly available RNA-Seq datasets, we identified several alternatively-spliced genes with switch-like, on/off expression properties, as well as a number of other genes that varied more subtly in isoform expression. In many cases, genes exhibiting differential expression of alternatively spliced transcripts were not differentially expressed at the gene level.ConclusionsGiven that changes in isoform expression level frequently involve a continuum of isoform ratios, rather than all-or-nothing expression, and that they are often independent of general gene expression changes, we anticipate that our research will contribute to revealing a so far uninvestigated layer of the transcriptome. We believe that, in the future, researchers will prioritize genes for functional analysis based not only on observed changes in gene expression levels, but also on changes in alternative splicing.

“Pachyostosis” in aquatic amniotes: a review

During the course of amniote evolution, numerous taxa secondarily adapted to an aquatic life. It appears that many of these taxa primitively display "pachyostosis," an osseous specialization characterized by an increase in bone compactness and/or volume. The term "pachyostosis" is used in morphological and histological descriptions to describe what in fact corresponds to different patterns. The aim of this paper is to present the current state of knowledge relative to this adaptation among aquatic amniotes. All the taxa that have returned to an aquatic environment are listed. Moreover, their degree of adaptation to the marine environment, their life environment, and the nature of their "pachyostotic" pattern, when present, are described. This inventory enables the evaluation of the current quality of the data relative to this specialization and provides an indication of the work that remains to be done. The functional consequences of "pachyostosis," and notably its importance for buoyancy control in the context of hydrostatic regulation of the body trim, are discussed and opposed to the requirement of improved swimming abilities in the case of a hydrodynamic mode of trim regulation. Questions are posed about the signification of the polymorphism displayed by this specialization between different taxa, different specimens of the same taxon and different bones of the same specimen, and the problem of quantification of pachyostosis is discussed.

An accurate quantitative method for the analysis of terpenes in milk fat by headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry

HS-SPME analysis of terpenes does usually have inherent quantification problems when working with complex samples, especially due to the matrix effect of the substrate or the calibration solution. Three different terpene carrier matrices were compared: methanol, synthetic oil and milk fat obtained by centrifugation from milk cream. Considerable differences in calibration sensitivity parameters were observed depending on the matrix used and on the type of terpene standard analysed. For milk sample quantification purposes internal standard method was preferred using milk fat as calibration matrix. Linearity range, repeatability, recovery and limits of detection and quantification were determined. Validation parameters were different depending on the concentration and molecular structure of each terpene analysed, particularly between mono- and sesquiterpenes. The method was useful to determine in an accurate manner the terpene content in milk samples from pasture fed animals, and it will help to establish objective terpene levels to differentiate milks from specific production systems.

The Moscow HUPO Human Proteome Project Workshop

The Moscow HUPO Human Proteome Project Workshop

Quantification of a Ti(C xN 1− x) based multilayer by Auger Electron Spectroscopy

Auger Electron Spectroscopy (AES) is an analytical technique sensitive to the surface of materials and providing elemental and chemical composition of conductive samples. The excellent spatial resolution and its quantification possibilities, even for light elements, make AES a commonly used technique to investigate surface and interfaces. TiN-like materials have a wide range of applications depending on their stoichiometry, but their composition is still complex (or at least not straightforward) to determine because of a strong overlapping of the Ti LMM with the N KLL Auger transitions. This quantification problem can be circumvented using computerised calculations as target factor analysis (TFA) to estimate the different nitrogen and titanium contributions in this peaks overlap. However, a more simple method, based on the study of Ti LMM and Ti LMV area ratio of pure TiN and TiC reference samples, is described in this paper and can be used to obtain the atomic composition of any titanium nitride based compound, whatever the complexity of the material. This method is an alternative to easily quantify TiN-like compounds by AES. As an illustration, a Ti(C x N 1− x ) based multilayer deposited on a hardmetal substrate was investigated. This quantification method was successfully used to evidence three different layers and the diffusion phenomenon at the interfaces between the layers. This study was completed with a quantitative SIMS depth profile that the high sensitivity and depth resolution allowed to measure the small variations of composition lower than the uncertainty of AES.

Central ray method in the problem of preference intensity quantification based on paired comparisons

It is shown that the problem of computation of importance factors for objects (as user preference intensity indices of these objects) based on interval results of paired comparisons of the considered objects, can be successfully solved by of the described central ray method. A description of specific features of the method is presented by the means of graph theory. An example of finding the importance factors for objects connected by quasiheirarchial preference structure is presented. The described method and the Saaty eigen-vector method are compared.

Assessment of endogenous androgen levels in meat, liver and testis of Iranian native cross-breed male sheep and bull by gas chromatography-mass spectrometry

Androgenic steroids always exist in different animal tissues at trace level, with significant numbers of interfering compounds, which makes their determination difficult. To solve some of the problems in quantification of the natural steroids in those tissues, a new GC-MS method was developed in this study. By using a surrogate analyte approach, which was developed in the authors’ previous studies, and extensive sample preparation procedure, which successfully eliminates many of the interfering compounds and resulting in a cleaner extract, accuracy, precision, sensitivity and selectivity of the method for the determination of steroids in complex matrices such as meat, liver and testis were improved. By aid of this method, the levels of androgens in different tissues of Iranian native cross-breed bulls and male sheep were determined. According to the results obtained in the present study, although the androgenic profile (contents and ratios of precursors and metabolites to the main hormones) is similar between the same tissues of both animals, the total androgenic content of each tissue is higher in the bull than the same tissue in male sheep. In addition, in both animals higher amount of androgens were found in liver in comparison with meat and testis.

The shell game: analytic problems in archaeological mollusc quantification

MNI calculations for archaeological molluscs that rely on counts of non-repetitive elements (NREs) are popular for their analytic speed and efficiency. Yet the reliability of this approach as compared to ‘traditionally’ calculated MNI has not been explored. Here, I examine these approaches using data from the Caribbean coastal midden site of Grand Bay, Carriacou. Results suggest that an NRE-based approach to MNI calculation can be unreliable under certain circumstances. In addition, dependence on the NRE-based method may hinder the integration of invertebrate with vertebrate data, obscuring a holistic understanding of prehistoric diet and resource exploitation. These findings are discussed in relation to practical constraints and fulfillment of zooarchaeological goals.

Metaontology and the problem of quantification

This text is concerned with the latest philosophical discipline - metaontology - which main objective is to examine traditional metaphysics and ontological sentences which it includes, as well as with its main theories pluralism, realism and skepticism. While first two of these theories try to provide more or less acceptable arguments in their favor, and show that quantification is justified, it will be shown that they make crucial mistake by neglecting problem of ontological commitment, which is, basically, main source of all metaphysical issues. I shall try to put forward advantages of skepticism over these rival theories, and why one should embrace it in metaontology.

Production and use of mycotoxins uniformly enriched with stable isotopes for their dosage in biological samples

Due to their low concentrations in biological matrices, mycotoxin analyses often encounter detection and quantification problems, especially for toxicokinetic studies. We have developed a strategy to produce in a single process, several fungi secondary metabolites uniformly enriched with 13C, 15N stable isotopes in their 'natural' composition. This includes: (1) a plant culture in the presence of 10%, 50% or 100% 13CO2 as the only source of carbon, and in the presence or not of 10% 15N-enriched nitrogen salts – as expected wheat or maize uniformlyincorporate enriched isotopes into their bioproducts; (2) a subsequent solid culture of different filamentous fungi on plant biomass led to the production of a 'natural' mixture of isotopes-enriched mycotoxins – these compounds exhibit a characteristic isotopic cluster, which can be easily detected by mass spectrometry. As an example, we achieved 10% uniformly 13C-enriched zearalenone, deoxynivalenol and mycophenolic acid by growing Fusarium graminearum or Penicillium brevicompactum on 10% 13C enriched wheat seeds and 3 to 10% 13C, 15N uniformly enriched fumonisins from Fusarium verticillioides cultures on maize seeds or straw. These compounds were used for metabolism and transport studies in mammals either in vitro or in vivo and analysed by MS and MSn spectra of the isotopic cluster but also by 13C, 15N NMR. Moreover, such isotopic pattern enrichment can be used for quantitative evaluations of mycotoxins transport across mammalian biological membranes, alone or in their 'natural' conditions in the presence of other fungi secondary metabolites. Finally, we used such enriched compounds with high reliabilityin order to study zearalenone metabolism but these enriched compounds would also be used as internal standards to quantify zearalenone or fumonisins in contaminated food samples.

A community resource for high-throughput quantitative RT-PCR analysis of transcription factor gene expression in Medicago truncatula.

BackgroundMedicago truncatula is a model legume species that is currently the focus of an international genome sequencing effort. Although several different oligonucleotide and cDNA arrays have been produced for genome-wide transcript analysis of this species, intrinsic limitations in the sensitivity of hybridization-based technologies mean that transcripts of genes expressed at low-levels cannot be measured accurately with these tools. Amongst such genes are many encoding transcription factors (TFs), which are arguably the most important class of regulatory proteins. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is the most sensitive method currently available for transcript quantification, and one that can be scaled up to analyze transcripts of thousands of genes in parallel. Thus, qRT-PCR is an ideal method to tackle the problem of TF transcript quantification in Medicago and other plants.ResultsWe established a bioinformatics pipeline to identify putative TF genes in Medicago truncatula and to design gene-specific oligonucleotide primers for qRT-PCR analysis of TF transcripts. We validated the efficacy and gene-specificity of over 1000 TF primer pairs and utilized these to identify sets of organ-enhanced TF genes that may play important roles in organ development or differentiation in this species. This community resource will be developed further as more genome sequence becomes available, with the ultimate goal of producing validated, gene-specific primers for all Medicago TF genes.ConclusionHigh-throughput qRT-PCR using a 384-well plate format enables rapid, flexible, and sensitive quantification of all predicted Medicago transcription factor mRNAs. This resource has been utilized recently by several groups in Europe, Australia, and the USA, and we expect that it will become the 'gold-standard' for TF transcript profiling in Medicago truncatula.

Quantification of Enterococcus italicus in traditional Italian cheeses by fluorescence whole-cell hybridization

The objective of this work was to investigate the spread of Enterococcus italicus in cheese. For this purpose, a fluorescence whole-cell hybridization protocol (FWCH) with a 16S rRNA probe was optimized to evaluate the presence and abundance of this organism in artisanal Italian cheeses. The FWCH method avoided the quantification problems using classical plate count techniques related to the well-known difficulties to cultivate E. italicus in selective enterococci media. After probe and FWCH optimization, 10 commercially available Italian semi-hard cheeses made with raw ewe or cow milk without starter addition were analyzed. All of them were subjected to FWCH experiments and six of them gave positive results with the probe, i.e. the E. italicus content was >4 log cells/g according to the detection limit of FWCH. Counts showed that E. italicus was present at levels ranging from 5.91±0.17 to 7.34±0.14 log cells/g; such levels were similar to, or even higher than, the total enterococci counted from the corresponding cheeses using kanamycin aesculin azide agar. The overall reliability of the FWCH method was tested by species-specific PCR. The positive amplification of the expected 323 bp fragment from both a cheese matrix and cell bulks of cheese samples containing high loads of this organism (as determined by FWCH counts) and the successful isolation of E. italicus strains from the above cheeses provided definitive proof of both probe specificity and the presence of this organism in cheeses. Although there is very little available quantitative data on the incidence of E. italicus in cheese, or its role in product quality, this study showed a wide diffusion of this organism in artisanal cheeses, where secondary non-starter lactic acid bacterial microflora, which enterococci belong to, may become dominant during ripening.

Enhanced qualitative probabilistic networks for resolving trade-offs

Qualitative probabilistic networks were designed to overcome, to at least some extent, the quantification problem known to probabilistic networks. Qualitative networks abstract from the numerical probabilities of their quantitative counterparts by using signs to summarise the probabilistic influences between their variables. One of the major drawbacks of these qualitative abstractions, however, is the coarse level of representation detail that does not provide for indicating strengths of influences. As a result, the trade-offs modelled in a network remain unresolved upon inference. We present an enhanced formalism of qualitative probabilistic networks to provide for a finer level of representation detail. An enhanced qualitative probabilistic network differs from a basic qualitative network in that it distinguishes between strong and weak influences. Now, if a strong influence is combined, upon inference, with a conflicting weak influence, the sign of the net influence may be readily determined. Enhanced qualitative networks are purely qualitative in nature, as basic qualitative networks are, yet allow for resolving some trade-offs upon inference.

Multiscale finite element methods for stochastic porous media flow equations and application to uncertainty quantification

In this paper, we study multiscale finite element methods for stochastic porous media flow equations as well as applications to uncertainty quantification. We assume that the permeability field (the diffusion coefficient) is stochastic and can be described in a finite dimensional stochastic space. This is common in applications where the coefficients are expanded using chaos approximations. The proposed multiscale method constructs multiscale basis functions corresponding to sparse realizations, and these basis functions are used to approximate the solution on the coarse-grid for any realization. Furthermore, we apply our coarse-scale model to uncertainty quantification problem where the goal is to sample the porous media properties given an integrated response such as production data. Our algorithm employs pre-computed posterior response surface obtained via the proposed coarse-scale model. Using fast analytical computations of the gradients of this posterior, we propose approximate Langevin samples. These samples are further screened through the coarse-scale simulation and, finally, used as a proposal in Metropolis–Hasting Markov chain Monte Carlo method. Numerical results are presented which demonstrate the efficiency of the proposed approach.

Frequency-selective robust detection and estimation of polymorphic QR signals

Nuclear quadrupole resonance (NQR) is a non-invasive, solid state, radio frequency (RF) technique, able to distinguish between polymorphic forms of certain compounds. Exploiting the signals from multiple polymorphs is important in explosives detection, whilst quantifying these polymorphs is important in pharmaceutical applications. Recently proposed hybrid algorithms, able to process the signals from multiple polymorphs, assume that the amplitudes associated with each polymorph are known to be within a scaling. Any error in this a priori information will lead to performance degradation in these algorithms. In this paper, we develop a robust hybrid algorithm allowing for uncertainties in the assumed amplitudes, extending a recently proposed robust algorithm, formulated for single polymorphs, to process signals from multiple polymorphs. In the proposed robust algorithm, the amplitudes are allowed to vary within an uncertainty hyper-sphere whose radius is evaluated using analytical expressions derived herein. Extensive numerical investigations indicate that the proposed algorithm provides significant performance gains as compared to both the existing hybrid algorithms, when uncertainties in the amplitudes exist, and the existing robust algorithm, when there are multiple polymorphs. Finally, the Cramér–Rao lower bound is derived for the uncertain data case as a reference for the quantification problem.