Showing papers by "University of Paris published in 2022"

Highly reactive Cu-Pt bimetallic 3D-electrocatalyst for selective nitrate reduction to ammonia

Abstract: Identifying electrocatalytic materials that generate fossil-free ammonia through N-recycling from polluted water sources is required. Bimetallic Cu-Pt foam electrodes were synthesized to enhance electrochemical reduction of nitrate (ERN) by the introduction of bimetallic catalytic sites. Electrodes were benchmarked against Cu foam using engineering figures of merit. Cu-Pt (180 s) electrode achieved 94% conversion of NO3--N in 120 min yielding 194.4 mg NH3- N L-1 gcat-1, with a selectivity towards ammonia (SNH3) of 84% and an electrical energy per order decrease by ~70% respect pristine Cu foam. Bimetallic electrodes with low Pt loadings (<0.50 wt%) demonstrated that synergistic effects of Cu-Pt nanointerfaces enabled hybridized mechanisms of catalytic electrochemical and hydrogenation reduction processes. These encouraging outcomes emphasize the potential of Cu-Pt foam electrodes to treat contaminated water sources with nitrate, while allowing a sustainable decentralized ammonia recovery. Enriched water for crops irrigation can therefore be a prospect use for this added value product.

Applications of biosensors for bacteria and virus detection in food and water–A systematic review

Abstract: Biosensors for sensitive and specific detection of foodborne and waterborne pathogens are particularly valued for their portability, usability, relatively low cost, and real-time or near real-time response. Their application is widespread in several domains, including environmental monitoring. The main limitation of currently developed biosensors is a lack of sensitivity and specificity in complex matrices. Due to increased interest in biosensor development, we conducted a systematic review, complying with the PRISMA guidelines, covering the period from January 2010 to December 2019. The review is focused on biosensor applications in the identification of foodborne and waterborne microorganisms based on research articles identified in the Pubmed, ScienceDirect, and Scopus search engines. Efforts are still in progress to overcome detection limitations and to provide a rapid detection system which will safeguard water and food quality. The use of biosensors is an essential tool with applicability in the evaluation and monitoring of the environment and food, with great impact in public health.

Trends and the course of liver cirrhosis and its complications in Germany: Nationwide population-based study (2005 to 2018)

Abstract: Background Cirrhosis is known to have a high prevalence and mortality worldwide. However, in Europe, the epidemiology of cirrhosis is possibly undergoing demographic changes, and etiologies may have changed due to improvements in standard of care. The aim of this population-based study was to analyze the trends and the course of liver cirrhosis and its complications in recent years in Germany. Methods We analyzed the data of all hospital admissions in Germany within diagnosis-related groups from 2005 to 2018. The diagnostic records of cirrhosis and other categories of diseases were based on ICD-10-GM codes. The primary outcome measurement was in-hospital mortality. Trends were analyzed through Poisson regression of annual number of admissions. The impact of cirrhosis on overall in-hospital mortality were assessed through the multivariate multilevel logistic regression model adjusted for age, sex, and comorbidities. Findings Of the 248,085,936 admissions recorded between 2005 and 2018, a total of 2,302,171(0•94%) were admitted with the diagnosis of cirrhosis, mainly as a comorbidity. Compared with other chronic diseases, patients admitted with cirrhosis were younger, mainly male and had the highest in-hospital mortality rate. Diagnosis of cirrhosis was an independent risk factor of in-hospital mortality with the highest odds ratio (OR:6•2[95%CI:6.1-6•3]) among all diagnoses. The prevalence of non-alcoholic fatty liver disease has increased four times from 2005 to 2018, while alcoholic cirrhosis is 20 times than other etiologies. Bleeding was found to be decreasing over time, but ascites remained the most common complication and was increasing. Interpretation This nationwide study demonstrates that cirrhosis represents a considerable healthcare burden, as shown by the increasing in-hospital mortality, also in combination with other chronic diseases. Alcohol-related cirrhosis and complications are on the rise. More resources and better management strategies are warranted. Funding The funders had no influence on this study.

Friction pressure on relativistic bubble walls

Abstract: A bstract During a cosmological first-order phase transition, particles of the plasma crossing the bubble walls can radiate a gauge boson. The resulting pressure cannot be computed perturbatively for large coupling constant and/or large supercooling. We resum the real and virtual emissions at all leading-log orders, both analytically and numerically using a Monte-Carlo simulation. We find that radiated bosons are dominantly soft and that the resulting retarding pressure on relativistic bubble walls is linear both in the Lorentz boost and in the order parameter, up to a log. We further quantitatively discuss IR cut-offs, wall thickness effects, the impact of various approximations entering the calculation, and comment on the fate of radiated bosons that are reflected.

Implementation of the new EU IVD regulation - urgent initiatives are needed to avert impending crisis.

Abstract: Laboratory medicine in the European Union is at the dawn of a regulatory revolution as it reaches the end of the transition from IVDD 98/79/EC (https://eur-lex.eur-opa.eu/legal-content/EN/TXT/?uri=CELEX%3A31998L0079&qid=1628781352814) to IVDR 2017/746 https://eur-lex.europa.eu/eli/reg/2017/746. Without amendments and contingency plans, implementation of the IVDR in May 2022 will lead the healthcare sector into uncharted waters due to unpreparedness of the EU regulatory infrastructure. Prospective risk analyses were not made by the European Commission, and if nothing happens it can be anticipated that the consequences will impact all stakeholders of the medical test pipeline, may seriously harm patients and may prevent caregivers from making appropriate clinical decisions due to non-availability of medical tests. Finally, it also may discourage manufacturers and academia from developing specialty tests, thereby hampering innovation in medical diagnostic care. We hereby inform laboratory professionals about the imminent diagnostic collapse using testimonies from representative stakeholders of the diagnostic supply chain and from academia developing innovative in-house tests in domains of unmet clinical needs. Steps taken by the EFLM Task Force on European Regulatory Affairs, under the umbrella of the Biomedical Alliance in Europe, will be highlighted, as well as the search for solutions through dialogue with the European Commission. Although we recognize that the IVDR promotes positive goals such as increased clinical evidence, surveillance, and transparency, we need to ensure that the capabilities of the diagnostic sector are not damaged by infrastructural unpreparedness, while at the same time being forced to submit to a growing bureaucratic and unsupportive structure that will not support its "droit d'exister".

The crucial contribution of mixing to present and future ocean oxygen distribution

Abstract: The oxygen content of the ocean interior largely results from a balance between respiration and advective ventilation, with only a small contribution from mixing processes. However, two important characteristics, which are key to future oxygen distribution in the ocean, primarily depend on the strength of ocean mixing. The first relates to the oxygen minimum zones (OMZ), which are wide O2-deficient mesopelagic layers inhospitable to most marine macro-fauna. We illustrate how mixing intensity controls the volume of all major OMZs. The second relates to one of the most worrying responses of the ocean to climate change: deoxygenation, including in OMZs. Several observational and model studies show that reduction in oxygen mixing plays a dominant role in global deoxygenation. Uncertainties in the representation of mixing in Earth system models and difficulties to measure mixing rates in the field hinder our ability to project the future evolution of OMZs.

To catch a hijacker: abundance, evolution and genetic diversity of P4-like bacteriophage satellites

Abstract: Bacteriophages (phages) are bacterial parasites that can themselves be parasitized by phage satellites. The molecular mechanisms used by satellites to hijack phages are sometimes understood in grea...

High Prevalence of Klebsiella pneumoniae in European Food Products: a Multicentric Study Comparing Culture and Molecular Detection Methods

Abstract: The Klebsiella pneumoniae species complex (KpSC) is a leading cause of multidrug-resistant human infections. To better understand the potential contribution of food as a vehicle of KpSC, we conducted a multicentric study to define an optimal culture method for its recovery from food matrices and to characterize food isolates phenotypically and genotypically. Chicken meat (n = 160) and salad (n = 145) samples were collected in five European countries and screened for the presence of KpSC using culture-based and zur-khe intergenic region (ZKIR) quantitative PCR (qPCR) methods. Enrichment using buffered peptone water followed by streaking on Simmons citrate agar with inositol (44°C for 48 h) was defined as the most suitable selective culture method for KpSC recovery. A high prevalence of KpSC was found in chicken meat (60% and 52% by ZKIR qPCR and the culture approach, respectively) and salad (30% and 21%, respectively) samples. Genomic analyses revealed high genetic diversity with the dominance of phylogroups Kp1 (91%) and Kp3 (6%). A total of 82% of isolates presented a natural antimicrobial susceptibility phenotype and genotype, with only four CTX-M-15-producing isolates detected. Notably, identical genotypes were found across samples-same food type and same country (15 cases), different food types and same country (1), and same food type and two countries (1)-suggesting high rates of transmission of KpSC within the food sector. Our study provides a novel isolation strategy for KpSC from food matrices and reinforces the view of food as a potential source of KpSC colonization in humans. IMPORTANCE Bacteria of the Klebsiella pneumoniae species complex (KpSC) are ubiquitous, and K. pneumoniae is a leading cause of antibiotic-resistant infections in humans. Despite the urgent public health threat represented by K. pneumoniae, there is a lack of knowledge of the contribution of food sources to colonization and subsequent infection in humans. This is partly due to the absence of standardized methods for characterizing the presence of KpSC in food matrices. Our multicentric study provides and implements a novel isolation strategy for KpSC from food matrices and shows that KpSC members are highly prevalent in salads and chicken meat, reinforcing the view of food as a potential source of KpSC colonization in humans. Despite the large genetic diversity and the low levels of resistance detected, the occurrence of identical genotypes across samples suggests high rates of transmission of KpSC within the food sector, which need to be further explored to define possible control strategies.

Predicting plastic events and quantifying the local yield surface in 3D model glasses

Abstract: By applying the local yield stress (LYS) method to probe local regions of three-dimensional computational glass models, we confirm high correlations between the measured local yield stress ( Δ τ c ) and the plastic events when the parameterization of the method is properly optimized. The optimal probing region for this system is found to be ∼ 5 σ in radius, where σ represents the Lennard-Jones length scale, approximately the atomic size. The averaged correlation remains positive through the first 200 identified plastic events or 1/3 of the yielding strain ( ∼ 7 % ). Here we apply only the local probing that aligns perfectly with the loading on the boundary. The LYS measurements converge to a Weibull distribution with a minimum Δ τ c indistinguishable from zero at larger probing region radii. Analysis of the data in light of an assumption that Δ τ c is a local quantity that obeys extreme value statistics above a critical length scale bounds the exponent of the underlying partial distribution of Δ τ c ≲ 0 . 71 . A thorough investigation of the anisotropy of the local yield surface at the location of the first plastic event indicates that the first triggered region does not align perfectly with the loading on the boundary, but is well-predicted by projecting the shear applied at the boundary onto the local yield surface. This implies that the correlation between the local yield stress prediction and the resulting plasticity may be enhanced by performing a more complete assessment of the local yield surface at each sample point.

Identification of an endocannabinoid gut-brain vagal mechanism controlling food reward and energy homeostasis

Abstract: The regulation of food intake, a sine qua non requirement for survival, thoroughly shapes feeding and energy balance by integrating both homeostatic and hedonic values of food. Unfortunately, the widespread access to palatable food has led to the development of feeding habits that are independent from metabolic needs. Among these, binge eating (BE) is characterized by uncontrolled voracious eating. While reward deficit seems to be a major contributor of BE, the physiological and molecular underpinnings of BE establishment remain elusive. Here, we combined a physiologically relevant BE mouse model with multiscale in vivo approaches to explore the functional connection between the gut-brain axis and the reward and homeostatic brain structures. Our results show that BE elicits compensatory adaptations requiring the gut-to-brain axis which, through the vagus nerve, relies on the permissive actions of peripheral endocannabinoids (eCBs) signaling. Selective inhibition of peripheral CB1 receptors resulted in a vagus-dependent increased hypothalamic activity, modified metabolic efficiency, and dampened activity of mesolimbic dopamine circuit, altogether leading to the suppression of palatable eating. We provide compelling evidence for a yet unappreciated physiological integrative mechanism by which variations of peripheral eCBs control the activity of the vagus nerve, thereby in turn gating the additive responses of both homeostatic and hedonic brain circuits which govern homeostatic and reward-driven feeding. In conclusion, we reveal that vagus-mediated eCBs/CB1R functions represent an interesting and innovative target to modulate energy balance and counteract food-reward disorders.

A Dual Barcoding Approach to Bacterial Strain Nomenclature: Genomic Taxonomy of<i>Klebsiella pneumoniae</i>Strains

Abstract: Sublineages (SLs) within microbial species can differ widely in their ecology and pathogenicity, and their precise definition is important in basic research and for industrial or public health applications. Widely accepted strategies to define SLs are currently missing, which confuses communication in population biology and epidemiological surveillance. Here, we propose a broadly applicable genomic classification and nomenclature approach for bacterial strains, using the prominent public health threat Klebsiella pneumoniae as a model. Based on a 629-gene core genome multilocus sequence typing (cgMLST) scheme, we devised a dual barcoding system that combines multilevel single linkage (MLSL) clustering and life identification numbers (LINs). Phylogenetic and clustering analyses of >7,000 genome sequences captured population structure discontinuities, which were used to guide the definition of 10 infraspecific genetic dissimilarity thresholds. The widely used 7-gene multilocus sequence typing (MLST) nomenclature was mapped onto MLSL SLs (threshold: 190 allelic mismatches) and clonal group (threshold: 43) identifiers for backwards nomenclature compatibility. The taxonomy is publicly accessible through a community-curated platform (https://bigsdb.pasteur.fr/klebsiella), which also enables external users' genomic sequences identification. The proposed strain taxonomy combines two phylogenetically informative barcode systems that provide full stability (LIN codes) and nomenclatural continuity with previous nomenclature (MLSL). This species-specific dual barcoding strategy for the genomic taxonomy of microbial strains is broadly applicable and should contribute to unify global and cross-sector collaborative knowledge on the emergence and microevolution of bacterial pathogens.