Real-Time Dynamics of RNA Polymerase II Clustering in Live Human Cells

Transcription is reported to be spatially compartmentalized in nuclear transcription factories with clusters of RNA polymerase II (Pol II). However, little is known about when these foci assemble or their relative stability. We developed a quantitative single-cell approach to characterize protein spatiotemporal organization, with single-molecule sensitivity in live eukaryotic cells. We observed that Pol II clusters form transiently, with an average lifetime of 5.1 (± 0.4) seconds, which refutes the notion that they are statically assembled substructures. Stimuli affecting transcription yielded orders-of-magnitude changes in the dynamics of Pol II clusters, which implies that clustering is regulated and plays a role in the cell’s ability to effect rapid response to external signals. Our results suggest that transient crowding of enzymes may aid in rate-limiting steps of gene regulation

SPITFIR(e): A supermaneuverable algorithm for fast denoising and deconvolution of 3D fluorescence microscopy images and videos

International audienceModern fluorescent microscopy imaging is still limited by the optical aberrations and the photon budget available in the specimen. A direct consequence is the necessity to develop flexible and "off-road" algorithms in order to recover structural details and improve spatial resolution, which is critical when restraining the illumination to low levels in order to limit photo-damages. Here, we report SPITFIR(e) a flexible method designed to accurately and quickly restore 2D-3D fluorescence microscopy images and videos (4D images). We designed a generic sparse-promoting regularizer to subtract undesirable out-of-focus background and we developed a primal-dual algorithm for fast optimization. SPITFIR(e) is a "swiss-knife" method for practitioners as it adapts to any microscopy techniques, to various sources of signal degradation (noise, blur), to variable image contents, aswell as to low signal-to-noise ratios. Our method outperforms existing state-of-the-art algorithms, and is more flexible than supervised deep-learning methods requiring ground truth datasets. The performance, the flexibility, and the ability to push the spatiotemporal resolution limit of sub-diffracted fluorescence microscopy techniques are demonstrated on experimental datasets acquired with various microscopy techniques from 3D spinning-disk confocal up to lattice light sheet microscopy

Exploring the quality of life of cosmetic users: A cross-sectional analysis from eight Arab countries in the Middle East

Background The use of cosmetic products is growing in dominance in the Arab population, making it essential to measure its effects on users. The production of cosmetics has been largely driven by consumerism and a bid to keep abreast with the latest trends in the beauty industry with less attention on how the users' quality of life (QoL) is affected. Aims This study aims to investigate the effect of cosmetic products on users' quality of life in eight Arab countries. Methods A cross-sectional study was carried out using an online data collection approach. A validated and specialist instrument tool called BeautyQoL, which consists of five domains and a total of 52 questions, was distributed to a sample of 2219 cosmetic users. Descriptive and inferential statistical analysis was done using SPSS® version 26.0. Results The mean age of participants was 34 ± 11.25 years, and more women were represented in the sample (71%) than men. The majority of respondents had oily skin type (39.6%) and tan skin tone (30.4%). QoL through cosmetic use is computed with a mean score of 51 out of 100. The users' mean score satisfaction from cosmetic use is centred on attractiveness (56.1), followed by self-confidence (51.8). Cosmetics have a statistically significant effect on participants who are young adults, women, single, and employed with high income. As the respondents' skin tone deepens from very fair to dark, the mean score for each domain significantly increases, whereas when skin type changes from very oily to dry, the mean score for each domain decreases. Conclusion The effect of cosmetics on the users' QoL is limited, contrary to the narrative commonly portrayed in cosmetics' advertisements. Therefore, the use of cosmetics among the Arab population should be from an informed perspective of their specific needs instead of conforming to the viral trends pedaled by influencers and bloggers on social media, which might be irrelevant for them.Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australian University Librarians. [Correction added on 5 July 2022, after first online publication: CAUL funding statement has been added.]Scopu

Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions

Imagerie électro-optique Pockels aux échelles micro et nanométriques en physique et biophysique

The aim of this thesis is to validate the electro-optical Pockels microscopy as a powerful technique for electric field imaging at nano and micrometer scales. A first part of this manuscript is dedicated to the instrumental aspects of this new microscope modality. Then we discuss its application in physical and biophysical domains. We have investiguqted 2-methyl-4-nitroaniline(MNA) monocrystalline molecular thin films where the electric field distribution could be imaged, and crystal orientation retrieved. At sub-wavelength scale, we were able to isolate the electro-optical modulation of light scattered by isolated 150nm size KTiOP04 (KTP) nanoparticles. Using the angular dependency of the Pockels response to the polarization of light we could determine the a priori random, spatial orientation of the nanocrystal. Such electric-field nano-probe configuration could find its way in various applications. In the case of biological entities such as neurons, information is transmitted via an electric field signal, propagating through the plasmid membrane. We concentrated first on a model artificial membrane doped with the DI-8-ANEPPS nonlinear dye, evidencing for the first time a Pockels electro-optical response. A relatively high sensitivity to the electric field allows to envision interesting applications in living cells. Experiences performed with PC 12 cells have shown an optical response that reflects the electric field spatial distribution. This work demonstrates that the electro-optical microscopy is emerging as a new powerful tool for sub-wavelength investigation of electro-optical properties in physics and biology.Le but de ce mémoire est de valider la microscopie électro-optique Pockels comme méthode de mesure et de cartographie de champ électrique aux échelles micro et nanométriques. Une première partie est dédiée à la description de l’instrumentation d’imagerie mise en jeu. Nous développons ensuite son application en physique et biophysique. Une étude de couches minces monocristallines de 2-methyl-4-nitroaniline (MNA) a permis de sonder localement la variation de champ électrique appliqué, mais aussi d’étudier l’orientation des axes optiques de ce cristal dans l’espace. A l’échelle sub-longueur d’onde nous avons pu isoler la modulation électro-optique de la diffusion de lumière associée à une nanoparticule isolée de KTiOPO4 (KTP) d’une taille de 150nm. La dépendance polaire du signal Pockels sur la polarisation lumineuse incidente a permis de prédire l’orientation de la maille cristalline du KTP dans l’espace. De telles sondes de champs électriques nanométriques peuvent avoir de nombreuses applications en nano-photonique. Dans le cas d’entité biologiques comme des neurones, la propagation de l’information est assurée par celle d’un champ électrique dans les membranes plasmiques. Dans une première étape, nous nous sommes intéressés à l’étude de bicouches artificielles dopées par un colorant non-linéaire, le DI-8-ANEPPS. Un signal électro-optique Pockels y a été mesuré pour la première fois. La caractérisation de l’insertion du colorant dans la membrane a été aussi discutée. La grande sensibilité à la mesure d’un champ électrique assurée par l’interféromètre permet d’envisager des possibilités d’applications dans des cellules vivantes. Des expériences menées sur des cellules de type PC12 ont montré l’existence d’un signal optique qui est associé à la distribution spatiale du champ électrique. L’ensemble de ces travaux montrent que la microscopie électro-optique s’avère constituer un outil important pour la physique et biophysique

Electrooptical Pockels Imaging at micro and nanometric scale for physics and biophysics

Le but de ce mémoire est de valider la microscopie électro-optique Pockels comme méthode de mesure et de cartographie de champ électrique aux échelles micro et nanométriques. Une première partie est dédiée à la description de l’instrumentation d’imagerie mise en jeu. Nous développons ensuite son application en physique et biophysique. Une étude de couches minces monocristallines de 2-methyl-4-nitroaniline (MNA) a permis de sonder localement la variation de champ électrique appliqué, mais aussi d’étudier l’orientation des axes optiques de ce cristal dans l’espace. A l’échelle sub-longueur d’onde nous avons pu isoler la modulation électro-optique de la diffusion de lumière associée à une nanoparticule isolée de KTiOPO4 (KTP) d’une taille de 150nm. La dépendance polaire du signal Pockels sur la polarisation lumineuse incidente a permis de prédire l’orientation de la maille cristalline du KTP dans l’espace. De telles sondes de champs électriques nanométriques peuvent avoir de nombreuses applications en nano-photonique. Dans le cas d’entité biologiques comme des neurones, la propagation de l’information est assurée par celle d’un champ électrique dans les membranes plasmiques. Dans une première étape, nous nous sommes intéressés à l’étude de bicouches artificielles dopées par un colorant non-linéaire, le DI-8-ANEPPS. Un signal électro-optique Pockels y a été mesuré pour la première fois. La caractérisation de l’insertion du colorant dans la membrane a été aussi discutée. La grande sensibilité à la mesure d’un champ électrique assurée par l’interféromètre permet d’envisager des possibilités d’applications dans des cellules vivantes. Des expériences menées sur des cellules de type PC12 ont montré l’existence d’un signal optique qui est associé à la distribution spatiale du champ électrique. L’ensemble de ces travaux montrent que la microscopie électro-optique s’avère constituer un outil important pour la physique et biophysique.The aim of this thesis is to validate the electro-optical Pockels microscopy as a powerful technique for electric field imaging at nano and micrometer scales. A first part of this manuscript is dedicated to the instrumental aspects of this new microscope modality. Then we discuss its application in physical and biophysical domains. We have investiguqted 2-methyl-4-nitroaniline(MNA) monocrystalline molecular thin films where the electric field distribution could be imaged, and crystal orientation retrieved. At sub-wavelength scale, we were able to isolate the electro-optical modulation of light scattered by isolated 150nm size KTiOP04 (KTP) nanoparticles. Using the angular dependency of the Pockels response to the polarization of light we could determine the a priori random, spatial orientation of the nanocrystal. Such electric-field nano-probe configuration could find its way in various applications. In the case of biological entities such as neurons, information is transmitted via an electric field signal, propagating through the plasmid membrane. We concentrated first on a model artificial membrane doped with the DI-8-ANEPPS nonlinear dye, evidencing for the first time a Pockels electro-optical response. A relatively high sensitivity to the electric field allows to envision interesting applications in living cells. Experiences performed with PC 12 cells have shown an optical response that reflects the electric field spatial distribution. This work demonstrates that the electro-optical microscopy is emerging as a new powerful tool for sub-wavelength investigation of electro-optical properties in physics and biology

Tropical forest biomass estimation using polarimetric SAR tomography

Dans le cycle de carbone à l'échelle de la planète, la contribution des forêts tropicales, en tant que stock de carbone, est déterminante. Les études actuelles montrent que la connaissance précise de la biomasse forestière globale est nécessaire pour les modèles de prévision. C'est dans ce contexte que le projet BIOMASS est choisi par l'Agence spatiale européenne (ESA) comme une phase A du programme «Earth Core Mission». L'objectif de cette mission innovatrice est l'utilisation d'un système d'imagerie polarimétrique fonctionnant en bande P (435 MHz) pour la mesure de la biomasse forestière. La définition actuelle de la mission prévoit un mode tomographique rassurant une imagerie tri-dimentionnelle (3-D) de la forêt. Dans le cadre du projet BIOMASS, cette thèse de doctorat vise à développer une nouvelle stratégie pour la télédétection de la biomasse dans les forêts tropicales en utilisant des données multi-baseline acquises par le radar à ouverture synthétique (SAR) en bande P. Une approche originale consite à combiner la tomographie et le modèle RvoG (Random-Volume-over-Ground) établi et vérifié avec la technique PolInSAR (polarimetric SAR Interferometry). L'environnement forestier peut être décrit avec précision par un modèle polarimétrique multicouche (sol et succession de couches végétales). Une généralisation multi-baseline du modèle RVoG implique un certain nombre de paramètres qui peuvent être estimés à partir des données SAR en utilisant des méthodes spectrales haute résolution. Ainsi, une cartographie de la forêt et du sol peut être réalisée à l'aide de données tomographiques. De plus, la capacité des techniques tomographiques permet d'estimer la distribution verticale de la puissance rétrodiffusée. Ainsi, une information précise sur la biomasse peut être extraite de la puissance mesurée dans un domaine adapté à la couche de végétation. Cependant, cette puissance mesurée peut être fortement affectée par l'écho du sol dû à la contribution de double rebond. Et par suite, le principal défi peut être résumé par l'élaboration d'un nouvel estimateur de la biomasse forestière lié à une puissance rétrodiffusée mesurée avec une polarisation et un domaine vertical, tous les deux sont adaptés à la couche de végétation. Les algorithmes développés pour la cartographie de la forêt, l'estimation et la simulation de la biomasse sont appliqués et validés sur des données SAR aéroportées réalisées lors de la campagne TROPISAR en Guyane.Forested areas cover one third of earth's land surface and their contribution in the storage of carbon is decisive. Current studies show that the accurate knowledge of global forest biomass is necessary for the prediction of climate changes on the planet. In this context, the BIOMASS project is selected by the European Space Agency (ESA) as Phase A of the 'Earth Core Mission' program. This highly innovative mission consists of the use of a polarimetric imaging radar operating at P band (435 MHz) for the measurement of forest biomass. The current definition of the mission provides a three-dimensional imaging (3-D) of the forest with both tomographic and multi-pass interferometric modes. In the framework of this project, this PHD thesis aims to develop a novel strategy for the remote sensing of the biomass within the dense tropical forests by processing on multi-baseline P-band Synthetic Aperture Radar (SAR) data. An original approach combines the possibilities of 3-D exploration tomography and the Random-Volume- over-Ground (RVoG) model established and verified with PolInSAR technique (Polarimetric Interferometry SAR). The forested environment can be accurately described by a polarimetric multi-layer model (soil and a succession of vegetationlayers). A multi-baseline generalization of the RVoG model involves a certain number of parameters which must be estimated from radar observation data by using High- Resolution spectral estimation tomographic methods. Thereby, a cartography of the forest and its underlying ground can be made using tomographic data. Furthermore, the capacity of the tomographic techniques on 3-D imaging allows an estimation of the vertical distribution of the backscattered power. Thus, an accurate biomass information may be extracted from the power measured at a domain adapted to the canopy layer. However, this measured backscattered may be strongly affected by the ground echo due to the double bounce contribution. The main challenge of this thesis is to establish a novel biomass estimator related to a backscattered powermeasured with a polarimetric channel and at a vertical domain, both adapted to the canopy layer. The proposed algorithms of forest cartography and biomass estimation are applied and validated on Airborne P-band SAR data realized on the TROPISAR campaign in French Guyana

Imagerie électro-optique Pockels aux échelles micro et nanométriques en physique et biophysique

Le but de ce mémoire est de valider la microscopie électro-optique Pockels comme méthode de mesure et de cartographie de champ électrique aux échelles micro et nanométriques. Une première partie est dédiée à la description de l instrumentation d imagerie mise en jeu. Nous développons ensuite son application en physique et biophysique. Une étude de couches minces monocristallines de 2-methyl-4-nitroaniline (MNA) a permis de sonder localement la variation de champ électrique appliqué, mais aussi d étudier l orientation des axes optiques de ce cristal dans l espace. A l échelle sub-longueur d onde nous avons pu isoler la modulation électro-optique de la diffusion de lumière associée à une nanoparticule isolée de KTiOPO4 (KTP) d une taille de 150nm. La dépendance polaire du signal Pockels sur la polarisation lumineuse incidente a permis de prédire l orientation de la maille cristalline du KTP dans l espace. De telles sondes de champs électriques nanométriques peuvent avoir de nombreuses applications en nano-photonique. Dans le cas d entité biologiques comme des neurones, la propagation de l information est assurée par celle d un champ électrique dans les membranes plasmiques. Dans une première étape, nous nous sommes intéressés à l étude de bicouches artificielles dopées par un colorant non-linéaire, le DI-8-ANEPPS. Un signal électro-optique Pockels y a été mesuré pour la première fois. La caractérisation de l insertion du colorant dans la membrane a été aussi discutée. La grande sensibilité à la mesure d un champ électrique assurée par l interféromètre permet d envisager des possibilités d applications dans des cellules vivantes. Des expériences menées sur des cellules de type PC12 ont montré l existence d un signal optique qui est associé à la distribution spatiale du champ électrique. L ensemble de ces travaux montrent que la microscopie électro-optique s avère constituer un outil important pour la physique et biophysique.The aim of this thesis is to validate the electro-optical Pockels microscopy as a powerful technique for electric field imaging at nano and micrometer scales. A first part of this manuscript is dedicated to the instrumental aspects of this new microscope modality. Then we discuss its application in physical and biophysical domains. We have investiguqted 2-methyl-4-nitroaniline(MNA) monocrystalline molecular thin films where the electric field distribution could be imaged, and crystal orientation retrieved. At sub-wavelength scale, we were able to isolate the electro-optical modulation of light scattered by isolated 150nm size KTiOP04 (KTP) nanoparticles. Using the angular dependency of the Pockels response to the polarization of light we could determine the a priori random, spatial orientation of the nanocrystal. Such electric-field nano-probe configuration could find its way in various applications. In the case of biological entities such as neurons, information is transmitted via an electric field signal, propagating through the plasmid membrane. We concentrated first on a model artificial membrane doped with the DI-8-ANEPPS nonlinear dye, evidencing for the first time a Pockels electro-optical response. A relatively high sensitivity to the electric field allows to envision interesting applications in living cells. Experiences performed with PC 12 cells have shown an optical response that reflects the electric field spatial distribution. This work demonstrates that the electro-optical microscopy is emerging as a new powerful tool for sub-wavelength investigation of electro-optical properties in physics and biology.CACHAN-ENS (940162301) / SudocSudocFranceF