345 research outputs found
patRoon: open source software platform for environmental mass spectrometry based non-target screening
Occurrence, Fate, and Related Health Risks of PFAS in Raw and Produced Drinking Water
This study investigates
human exposure to per- and polyfluoroalkyl
substances (PFAS) via drinking water and evaluates human health risks.
An analytical method for 56 target PFAS, including ultrashort-chain
(C2–C3) and branched isomers, was developed. The limit of detection
(LOD) ranged from 0.009 to 0.1 ng/L, except for trifluoroacetic-acid
and perfluoropropanoic-acid with higher LODs of 35 and 0.24 ng/L,
respectively. The method was applied to raw and produced drinking
water from 18 Dutch locations, including groundwater or surface water
as source, and applied various treatment processes. Ultrashort-chain
(300 to 1100 ng/L) followed by the group of perfluoroalkyl-carboxylic-acids
(PFCA, ≥C4) (0.4 to 95.1 ng/L) were dominant. PFCA and perfluoroalkyl-sulfonic-acid
(≥C4), including precursors, showed significantly higher levels
in drinking water produced from surface water. However, no significant
difference was found for ultrashort PFAS, indicating the need for
groundwater protection. Negative removal of PFAS occasionally observed
for advanced treatment indicates desorption and/or degradation of
precursors. The proportion of branched isomers was higher in raw and
produced drinking water as compared to industrial production. Drinking
water produced from surface water, except for a few locations, exceed
non-binding provisional guideline values proposed; however, all produced
drinking waters met the recent soon-to-be binding drinking-water-directive
requirements
Interobserver variability between experienced and inexperienced observers in the histopathological analysis of Wilms tumors:a pilot study for future algorithmic approach
Contains fulltext :
236892.pdf (Publisher’s version ) (Open Access
Fast automatic quantitative cell replication with fluorescent live cell imaging
Hoffmann N, Keck M, Neuweger H, et al. Combining peak- and chromatogram-based retention time alignment algorithms for multiple chromatography-mass spectrometry datasets. BMC Bioinformatics. 2012;13(1): 21.Background
Modern analytical methods in biology and chemistry use separation techniques coupled to sensitive detectors, such as gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS). These hyphenated methods provide high-dimensional data. Comparing such data manually to find corresponding signals is a laborious task, as each experiment usually consists of thousands of individual scans, each containing hundreds or even thousands of distinct signals. In order to allow for successful identification of metabolites or proteins within such data, especially in the context of metabolomics and proteomics, an accurate alignment and matching of corresponding features between two or more experiments is required. Such a matching algorithm should capture fluctuations in the chromatographic system which lead to non-linear distortions on the time axis, as well as systematic changes in recorded intensities. Many different algorithms for the retention time alignment of GC-MS and LC-MS data have been proposed and published, but all of them focus either on aligning previously extracted peak features or on aligning and comparing the complete raw data containing all available features.
Results
In this paper we introduce two algorithms for retention time alignment of multiple GC-MS datasets: multiple alignment by bidirectional best hits peak assignment and cluster extension (BIPACE) and center-star multiple alignment by pairwise partitioned dynamic time warping (CEMAPP-DTW). We show how the similarity-based peak group matching method BIPACE may be used for multiple alignment calculation individually and how it can be used as a preprocessing step for the pairwise alignments performed by CEMAPP-DTW. We evaluate the algorithms individually and in combination on a previously published small GC-MS dataset studying the Leishmania parasite and on a larger GC-MS dataset studying grains of wheat (Triticum aestivum).
Conclusions
We have shown that BIPACE achieves very high precision and recall and a very low number of false positive peak assignments on both evaluation datasets. CEMAPP-DTW finds a high number of true positives when executed on its own, but achieves even better results when BIPACE is used to constrain its search space. The source code of both algorithms is included in the OpenSource software framework Maltcms, which is available from http://maltcms.sf.net webcite. The evaluation scripts of the present study are available from the same source
Robust Automated Tumour Segmentation on Histological and Immunohistochemical Tissue Images
Tissue microarray (TMA) is a high throughput analysis tool to identify new diagnostic and prognostic markers in human cancers. However, standard automated method in tumour detection on both routine histochemical and immunohistochemistry (IHC) images is under developed. This paper presents a robust automated tumour cell segmentation model which can be applied to both routine histochemical tissue slides and IHC slides and deal with finer pixel-based segmentation in comparison with blob or area based segmentation by existing approaches. The presented technique greatly improves the process of TMA construction and plays an important role in automated IHC quantification in biomarker analysis where excluding stroma areas is critical. With the finest pixel-based evaluation (instead of area-based or object-based), the experimental results show that the proposed method is able to achieve 80% accuracy and 78% accuracy in two different types of pathological virtual slides, i.e., routine histochemical H&E and IHC images, respectively. The presented technique greatly reduces labor-intensive workloads for pathologists and highly speeds up the process of TMA construction and provides a possibility for fully automated IHC quantification
Drawings of very preterm-born children at 5 years of age: a first impression of cognitive and motor development?
INTRODUCTION: The aim of this study was to examine differences in drawing skills between very preterm and term children, and to determine whether very preterm children's cognitive and motor development is reflected in the draw-a-person test (DAP) at age 5. Seventy-two very preterm children (birth weight <1,500 g and/or gestational age <32 weeks) and 60 term children at 5 years of age were compared on the DAP. Cognitive and motor skills of the very preterm children had been assessed four times, at 1/2, 1, 2, and 5 years of age. Very preterm children showed a developmental delay in drawing ability. Structural equation modeling revealed a positive relation between both cognitive as well as motor development and the DAP. CONCLUSION: The DAP could be a crude parameter for evaluating cognitive and motor deficits of very preterm children. A worrisome result should be followed by more standardized tests measuring cognitive and motor skill
El narcoperiodismo de García Márquez: uma análise dos aspectos da narcoliteratura no livro-reportagem Notícia de um sequestro
Desde os anos 1970, a cobertura da mídia tradicional sobre o narcotráfico caracterizou-se pela superficialidade de suas narrativas cujo processo impossibilita a profundidade de análise. Porém, alguns repórteres foram bem-sucedidos ao aproximar o narcotráfico e o jornalismo literário, rompendo com essa barreira limitante, principalmente, a partir da produção de livros-reportagem. O tema influenciou a literatura do continente (originando termos como narcoliteratura, narconarrativa e narcocultura), bem como o contexto do tráfico de drogas proporcionou a produção editorial de obras de não ficção, a partir dos final dos anos 80, atingindo o ápice nos anos 90 e 2000. Desta forma, este artigo discute o papel do livro-reportagem para a produção cultural da narcoliteratura, a partir de uma análise de seus aspectos dentro da obra jornalística Notícia de um sequestro (1996), de Gabriel García Márquez. O artigo está apoiado nos conceitos de livro-reportagem, de Edvaldo Pereira Lima e nas discussões sobre narcocultura, de Omar Rincón e de Diana Palaversich
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