16 research outputs found
Association between Ambient Noise Exposure and School Performance of Children Living in An Urban Area: A Cross-Sectional Population-Based Study
16 pages Article disponible à l'adresse suivante : http://link.springer.com/article/10.1007%2Fs11524-013-9843-6International audienceMost of the studies investigating the effects of the external noise on children's school performance have concerned pupils in schools exposed to high levels due to aircraft or freeway traffic noise. However, little is known about the consequences of the chronic ambient noise exposure at a level commonly encountered in residential urban areas. This study aimed to assess the relationship between the school performance of 8- to 9-year-old-children living in an urban environment and their chronic ambient noise exposure at home and at school. The children's school performances on the national standardized assessment test in French and mathematics were compared with the environmental noise levels. Children's exposure to ambient noise was calculated in front of their bedrooms (Lden) and schools (LAeq,day) using noise prediction modeling. Questionnaires were distributed to the families to collect potential confounding factors. Among the 746 respondent children, 586 were included in multilevel analyses. On average, the LAeq,day at school was 51.5 dB (SD= 4.5 dB; range = 38-58 dB) and the outdoor Lden at home was 56.4 dB (SD= 4.4 dB; range = 44-69 dB). LAeq,day at school was associated with impaired mathematics score (p = 0.02) or impaired French score (p = 0.01). For a + 10 dB gap, the French and mathematics scores were on average lower by about 5.5 points. Lden at home was significantly associated with impaired French performance when considered alone (p < 10(-3)) and was borderline significant when the combined home-school exposure was considered (p = 0.06). The magnitude of the observed effect on school performance may appear modest, but should be considered in light of the number of people who are potentially chronically exposed to similar environmental noise levels
Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020
We show the distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three genomic nomenclature systems to all sequence data from the World Health Organization European Region available until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation, compare the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Chemical tools for the study of epigenetic mechanisms
The overall goal of my work was to develop and apply new chemical methods for the study of epigenetic DNA and protein modifications.
In Chapter 3 the development of Suzuki-Miyaura cross coupling (SMcc) for the post-synthetic modification of DNA is described. DNA modification by SMcc is efficient (4-6h) and proceeds under
mild conditions (37°C, pH 8.5). The incorporation of various groups useful for biological investigations is demonstrated using this methodology. Using a photocrosslinker, introduced into the DNA by SMcc capture experiments are performed to identify potential binding partners of modified DNA.
In Chapter 4 a dehydroalanine (Dha) based chemical protein modification method is described that enables the introduction of posttranslational modification (PTM) mimics into histones. The PTM
mimics introduced by this method are tested using western- and dot-blot and binding and enzymatic assays, confirming they function as mimics of the natural modifications.
Chapter 5 describes the use of a generated PTM mimics to elucidate the function of O-linked β-Nacetylglucosamine (GlcNAc) of histones in transcriptional regulation. It is shown that GlcNAcylation of
Thr-101 on histone H2A can destabilize nucleosome by modulating the H2A/B dimer – H3/H4 tetramer interface.
N- and C-terminal histone tails play an important role in transcriptional regulation. In Chapter 6, nuclear magnetic resonance is used to investigate the structure of the histone H3 N-terminal tail in a nucleosome. The H3 tail, while intrinsically disordered, gains some α-helical character and adopts a compact conformation in a nucleosome context. This H3 tail structure is shown to be modulated by Ser-10 phosphorylation.
The effect of a new covalent DNA modification, 5- hydroxymethylcytosine (5hmC), on transcription factor binding is investigated in Chapter 7. 5hmC influences HIF1α/β, USF and MAX binding to their native recognition sequence, implying involvement of this modification in epigenetic regulation.This thesis is not currently available via ORA
Rapid Cross-Metathesis for Reversible Protein Modifications via Chemical Access to <i>Se</i>-Allyl-selenocysteine in Proteins
Cross-metathesis (CM) has recently
emerged as a viable strategy for protein modification. Here, efficient
protein CM has been demonstrated through biomimetic chemical access
to <i>Se</i>-allyl-selenocysteine (Seac), a metathesis-reactive
amino acid substrate, via dehydroalanine. On-protein reaction kinetics
reveal a rapid reaction with rate constants of Seac-mediated-CM comparable
or superior to off-protein rates of many current bioconjugations.
This use of <i>Se</i>-relayed Seac CM on proteins has now
enabled reactions with substrates (allyl GlcNAc, <i>N</i>-allyl acetamide) that were previously not possible for the corresponding
sulfur analogue. This CM strategy was applied to histone proteins
to install a mimic of acetylated lysine (KAc, an epigenetic marker).
The resulting synthetic H3 was successfully recognized by antibody
that binds natural H3-K9Ac. Moreover, Cope-type selenoxide elimination
allowed this putative marker (and function) to be chemically expunged,
regenerating an H3 that can be rewritten to complete a chemically
enabled “write (CM)–erase (ox)–rewrite (CM)”
cycle
In Situ Monitoring the Uptake of Moisture into Hybrid Perovskite Thin Films
Solution-processed
hybrid perovskites are of great interest for
use in photovoltaics. However, polycrystalline perovskite thin films
show strong degradation in humid atmospheres, which poses an important
challenge for large-scale market introduction. With in situ grazing
incidence neutron scattering (GISANS) we analyzed water content, degradation
products, and morphological changes during prolonged exposure to several
humidity levels. In high humidity, the formation of metastable hydrate
phases is accompanied by domain swelling, which transforms the faceted
crystals to a round-washed, pebble-like form. The films incorporate
much more water than is integrated into the hydrates, with smaller
crystals being more affected, making the degradation strongly dependent
on film morphology. Even at low humidity, water is adsorbed on the
crystal surfaces without the formation of crystalline degradation
products. Thus, although production in an ambient atmosphere is of
interest for industrial production it might lead to long-term degradation
without appropriate countermeasures like postproduction drying below
30% RH
Limited concordance of heparin/PF4 antibody assays for the diagnosis of heparin-induced thrombocytopenia: an analysis of the TORADI-HIT study.
BACKGROUND
Anecdotal reports suggest that the correlation between heparin/PF4 antibody assays for the diagnosis of heparin-induced thrombocytopenia (HIT) is limited. To address this issue, we investigated the correlation between widely used assays and examined possible factors contributing to variability.
METHODS
This is a large, prospective cohort study with 10 participating tertiary care hospitals including 1'393 patients with suspected HIT in clinical practice. HIT was defined by a positive heparin-induced platelet activation assay (HIPA; washed-platelet reference standard test). Three different immunoassays were used to measure heparin/PF4 antibodies: chemiluminescent immunoassay (CLIA), enzyme-linked immunosorbent assay (ELISA), and particle gel immunoassay (PaGIA). Various factors that could influence the assays were examined: sex (male, female), age (< 65 years, ≥ 65 years), unfractionated heparin exposure, presence of thrombosis, cardiovascular surgery, and intensive care unit. Spearman's correlation coefficients were calculated. Z-scores, and diagnostic odds ratios (DOR) were determined in above-mentioned subgroups of patients.
RESULTS
Among 1,393 patients, 119 were classified as HIT positive (prevalence 8.5%). The median 4Ts score was 5 in patients with HIT (interquartile range, IQR, 4-6), compared to 3 in patients without (IQR 2-4). Correlations (rs) between immunoassays were weak (0.53 to 0.65). Inconsistencies between immunoassays could not be explained by further analyses of z-scored test results and DOR in subgroups of patients.
CONCLUSIONS
The correlation between widely used heparin/PF4 antibody assays was weak and key factors could not explain this variability. Standardization of immunoassays is requested to improve comparability
Limited concordance of heparin/platelet factor 4 antibody assays for the diagnosis of heparin-induced thrombocytopenia: an analysis of the TORADI-HIT study
BACKGROUND
Anecdotal reports suggest that the correlation between heparin/platelet factor 4 (PF4) antibody assays for the diagnosis of heparin-induced thrombocytopenia (HIT) is limited.
OBJECTIVES
To investigate the correlation between widely used assays and examine possible factors contributing to variability.
METHODS
This is a large, prospective cohort study with 10 participating tertiary care hospitals including 1393 patients with suspected HIT in clinical practice. HIT was defined by a positive heparin-induced platelet activation (HIPA) assay (washed platelet reference standard test). Three different immunoassays were used to measure heparin/PF4 antibodies: chemiluminescent immunoassay, enzyme-linked immunosorbent assay, and particle gel immunoassay. Various factors that could influence the assays were examined: sex (male or female), age (<65 years or ≥65 years), unfractionated heparin exposure, presence of thrombosis, cardiovascular surgery, and intensive care unit. Spearman's correlation coefficients were calculated. Z-scores and diagnostic odds ratios were determined in the aforementioned subgroups of patients.
RESULTS
Among 1393 patients, 119 were classified as HIT-positive (prevalence, 8.5%). The median 4Ts score was 5 (IQR, 4-6) in patients with HIT compared with 3 (IQR, 2-4) in patients without HIT. Correlations (r) between immunoassays were weak (0.53-0.65). Inconsistencies between immunoassays could not be explained by further analyses of z-scored test results and diagnostic odds ratios in subgroups of patients.
CONCLUSION
The correlation between widely used heparin/PF4 antibody assays was weak, and key factors could not explain this variability. Standardization of immunoassays is requested to improve comparability
In Situ Monitoring the Uptake of Moisture into Hybrid Perovskite Thin Films
Solution-processed
hybrid perovskites are of great interest for
use in photovoltaics. However, polycrystalline perovskite thin films
show strong degradation in humid atmospheres, which poses an important
challenge for large-scale market introduction. With in situ grazing
incidence neutron scattering (GISANS) we analyzed water content, degradation
products, and morphological changes during prolonged exposure to several
humidity levels. In high humidity, the formation of metastable hydrate
phases is accompanied by domain swelling, which transforms the faceted
crystals to a round-washed, pebble-like form. The films incorporate
much more water than is integrated into the hydrates, with smaller
crystals being more affected, making the degradation strongly dependent
on film morphology. Even at low humidity, water is adsorbed on the
crystal surfaces without the formation of crystalline degradation
products. Thus, although production in an ambient atmosphere is of
interest for industrial production it might lead to long-term degradation
without appropriate countermeasures like postproduction drying below
30% RH