Effects of turbulence on diatoms of the genus Pseudo-nitzschia spp. and associated bacteria.

Turbulence is one of the least investigated environmental factors impacting the ecophysiology of phytoplankton, both at the community and individual species level. Here, we investigated, for the first time, the effect of a turbulence gradient (Reynolds number, from Reλ = 0 to Reλ = 360) on two species of the marine diatom Pseudo-nitzschia and their associated bacterial communities under laboratory conditions. Cell abundance, domoic acid (DA) production, chain formation, and Chl a content of P. fraudulenta and P. multiseries were higher for intermediate turbulence (Reλ = 160 or 240). DA was detectable only in P. multiseries samples. These observations were supported by transcriptomic analyses results, which suggested the turbulence related induction of the expression of the DA production locus, with a linkage to an increased photosynthetic activity of the total metatranscriptome. This study also highlighted a higher richness of the bacterial community associated with the nontoxic strain of P. fraudulenta in comparison to the toxic strain of P. multiseries. Bacillus was an important genus in P. multiseries cultures (relative abundance 15.5%) and its highest abundances coincided with the highest DA levels. However, associated bacterial communities of both Pseudo-nitzschia species did not show clear patterns relative to turbulence intensity.

On the conditions promoting Pseudo-nitzschia spp. blooms in the eastern English Channel and southern North Sea.

This study investigated the drivers of the blooms of Pseudo-nitzschia seriata and Pseudo-nitzschia delicatissima complexes in the eastern English Channel and southern North Sea. Phytoplankton data series acquired from 1992 to 2020 were analyzed with a multivariate statistical approach based on Hutchinson's niche concept. P. seriata and P. delicatissima complexes were found to be typically present year round, but they bloomed at different periods because they occupied different realized ecological niches. P. delicatissima complex occupied a more marginal niche and was less tolerant than P. seriata complex. P. delicatissima complex typically bloomed in April-May at the same time as Phaeocystis globosa while P. seriata complex blooms were more frequently observed in June during the decline of low intensity P. globosa blooms. P. delicatissima and P. seriata complexes were both favored by low-silicate environments and relatively low turbulence but they responded differently to water temperature, light, ammonium, phosphate and nitrite + nitrate conditions. Niche shifts and biotic interactions played important roles in the control of the blooms of P. delicatissima and P. seriata complexes. The two complexes occupied different sub-niches during their respective low abundance and bloom periods. The phytoplankton community structure and the number of other taxa presenting a niche overlapping the niches of P. delicatissima and P. seriata complexes also differed between these periods. P. globosa was the taxa contributing the most to the dissimilarity in community structure. P. globosa interacted positively with P. delicatissima complex and negatively with P. seriata complex.

An algorithm for the direct estimation of the parameters of the SIR epidemic model from the I(t) dynamics.

The discrete SIR (Susceptible-Infected-Recovered) model is used in many studies to model the evolution of epidemics. Here, we consider one of its dynamics-the exponential decrease in infected cases I(t). By considering only the I(t) dynamics, we extract three parameters: the exponent of the initial exponential increase γ ; the maximum value I max ; and the exponent of the final decrease Γ . From these three parameters, we show mathematically how to extract all relevant parameters of the SIR model. We test this procedure on numerical data and then apply the methodology to real data received from the COVID-19 situation in France. We conclude that, based on the hospitalized data and the ICU (Intensive Care Unit) cases, two exponentials are found, for the initial increase and the decrease in I(t). The parameters found are larger than reported in the literature, and they are associated with a susceptible population which is limited to a sub-sample of the total population. This may be due to the fact that the SIR model cannot be applied to the covid-19 case, due to its strong hypotheses such as mixing of all the population, or also to the fact that the parameters have changed over time, due to the political initiatives such as social distanciation and lockdown.

[Comparison of three albumin assay methods: a need for standardization within a healthcare area]. / Comparaison de trois techniques de dosage de l'albumine : un argument pour la standardisation des pratiques au sein d'un territoire de santé.

Albumin is a main biomarker of denutrition severity. Since 2019, the French National Authority of Health (HAS) recommends an immunologic technique as a reference for measuring albuminemia. In a context of partial recovery by the laboratory of GHBS (using colorimetric method with bromcresol purple) of the biological activity of the dialysis center, until then carried out by the Ouest biology - Biolor laboratory (using colorimetric method with bromcresol green) and in order to standardize practices in the healthcare sector, we compared 3 albumin assay techniques: immunoturbidimetric (Diagam®), BCG (Siemens®), BCP (Siemens®) on Siemens Atellica PLCs. The albumin level of 183 patient samples was measured. We show an overestimation of the dosage by the BCG (+ 5.46 g/L compared to IT) and an interference related to the inflammatory state of the patient during the dosage with this technique, as well as an underestimation of the dosage by the BCP (- 0.91 g/L relative to the IT), increased in patients with renal injury. This biological difference is added to a discrepancy in clinical conclusions. A change in dosing technique from BCG to BCP may impact the biological follow-up of patients and the PMSI score (mean difference of - 6.67 g/L between BCG and BCP while the classification of the severity of denutrition uses thresholds set in steps of 5 g/L). This variability of results should be taken into account by the clinicians and constitutes an argument in favor of the standardization of laboratories around a reference technique.

First Case of Brucellosis Caused by an Amphibian-type Brucella.

We report the first case of brucellosis caused by an isolate whose genome is identical that of a frog isolate from Texas, demonstrating the zoonotic potential of amphibian-type Brucella. Importantly, with such atypical Brucella, correct diagnosis cannot be performed using routine serological tests or identification methods.

A fatal case after an intravenous injection of levamisole.

Levamisole is a drug originally prescribed as an antihelmintic. Because of the occurrence of severe cases of agranulocytosis and leukoencephalitis it was removed from the French market in 1998 for human use, while it remains available for veterinary use. Nowadays in France its only use in humans is regulated by authorization for temporary use for its immunomodulatory properties in the treatment of nephritic syndrome.A 52-year-old man was found dead at his farm. Injection points were observed on his arm and a syringe containing a dark orange-brown liquid was found near the body. At his home, the discovery of a letter highlighted suicidal intent. Analysis of the aforementioned liquid, peripheral blood and urine confirmed the unique presence of levamisole. The femoral blood concentration of levamisole was of 25 mg/L whereas the femoral blood concentrations reported in cases of fatalities after cocaine use do not exceed 0.0056 mg/L. In humans, levamisole can be detected in biological samples after cocaine use as this drug is also an adulterant and one of its metabolites (aminorex) seems to have amphetamine-like properties. In this case, the man consumed levamisole from time to time for its stimulant and strengthening effects.Cases of fatal poisoning using levamisole are very rare and poorly documented, which makes the interpretation of postmortem blood levamisole concentration difficult.

[Analytical and clinical guidelines on neonatal bilirubinemia]. / Recommandations analytiques et cliniques pour l'utilisation de la bilirubinémie en néonatalogie.

The SFBC-CNBH-CNRHP "Neonatal bilirubin" working group performed a biological and clinical study on bilirubin use in neonates for reliable diagnosis and appropriate management of neonatal jaundice. A brief report of a national survey on analytical and biological practices in France is shown. The guidelines of the French Society of Neonatology (SFN) founded the decision of phototherapy set up upon an accurate lab measurement of total serum bilirubin. An abacus is proposed with defined thresholds, as a function of neonate lifetime in hours. However, several studies evidenced poor comparability of results obtained with the different available methods. This situation is partly due to the lack of reference materials, especially for high bilirubin concentrations. Clinical consequences might be observed. We present in this paper the results of a national harmonization study to progress on this issue. Beyond the analytical aspects, the clinical consequences of harmonization defects were investigated. Finally, guidelines for clinical laboratories are proposed, to be locally adapted.

[SFBC working group "Biochemical markers of COVID-19"]. / Groupe de travail SFBC « Marqueurs biochimiques de COVID-19 ¼.

The SARS-CoV-2 virus is responsible for an epidemic disease called COVID-19, which was initially evidenced in Wuhan, China, and spread very rapidly in China and around the world. In France, the first isolated case seems now to be reported in December 2019, stage 3 of the COVID-19 epidemic was triggered on March 14th, the start of the planned containment exit from May 11th. Healthcare services have faced a large influx of patients who may be beyond their capacity to receive and care, particularly in the Large-East and Ile-de-France regions. Some patients show an evolution of the disease never observed before with other coronaviruses and develop in a few days a very important inflammatory reaction, which can lead to death of patients. A working group of the French Society of Clinical Biology (SFBC) was set up with the objective of providing updated information on the current status of the biological prescriptions (focusing on biochemistry ones) and their evolution during the epidemic, and of analyzing the biological parameters associated with comorbidities and patient evolution in order to link biological results with medical events. The expanded working group covers all sectors of medical biology in France and extends to the French-speaking world: hospital sectors (CHU and CH, Army Training Hospitals) and the private sector opening a field of view on the biological situation in establishments for dependent elderly, social establishments and clinical medical institutions. The purpose of this article is the presentation of this working group and its immediate and future actions.

Soft Robots Manufacturing: A Review.

The growing interest in soft robots comes from the new possibilities offered by these systems to cope with problems that cannot be addressed by robots built from rigid bodies. Many innovative solutions have been developed in recent years to design soft components and systems. They all demonstrate how soft robotics development is closely dependent on advanced manufacturing processes. This review aims at giving an insight on the current state of the art in soft robotics manufacturing. It first puts in light the elementary components that can be used to develop soft actuators, whether they use fluids, shape memory alloys, electro-active polymers or stimuli-responsive materials. Other types of elementary components, such as soft smart structures or soft-rigid hybrid systems, are then presented. The second part of this review deals with the manufacturing methods used to build complete soft structures. It includes molding, with possibly reinforcements and inclusions, additive manufacturing, thin-film manufacturing, shape deposition manufacturing, and bonding. The paper conclusions sums up the pros and cons of the presented techniques, and open to developing topics such as design methods for soft robotics and sensing technologies.

[Cefazolin and coagulation disorders: a case report]. / Céfazoline et troubles de la coagulation : à propos d'un cas.

We report the case of a 79-year-old patient, admitted to the department of infectious diseases at Bretagne Sud Hospital Center for a right calcaneal osteitis, complicated by a pacemaker leads infectious endocarditis. Meticillin sensitive Staphylococcus aureus was documented by blood culture. Antibiotic treatment was established using intravenous cefazolin for an initial 6 weeks period. Prothrombin time (PT) decreased as well as vitamin K dependent factors, without anticoagulation therapy, at day 7 of cefazolin treatment. After bleeding occurred on calcaneal osteitis, the VAC® therapy system was removed and intravenous vitamin K 10 mg (then 5 mg per day for 5 days per os) was administered. Vitamin K allowed PT and vitamin K dependent factors to return to normal values. Literature review does not explicitly mention the effects on vitamin K dependent factors after cefazolin administration. Four severe haemorrhagic episodes under cefazolin have been declared in France so far since February 2017. The goal of this article is to alert clinicians and clinical pathologists from the potential appearance of coagulation disorders in patients treated by cefazolin.

Characterization of intermittency in zooplankton behaviour in turbulence.

We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of zooplankton patches in energetic environments.

Scaling Analysis of Ocean Surface Turbulent Heterogeneities from Satellite Remote Sensing: Use of 2D Structure Functions.

Satellite remote sensing observations allow the ocean surface to be sampled synoptically over large spatio-temporal scales. The images provided from visible and thermal infrared satellite observations are widely used in physical, biological, and ecological oceanography. The present work proposes a method to understand the multi-scaling properties of satellite products such as the Chlorophyll-a (Chl-a), and the Sea Surface Temperature (SST), rarely studied. The specific objectives of this study are to show how the small scale heterogeneities of satellite images can be characterised using tools borrowed from the fields of turbulence. For that purpose, we show how the structure function, which is classically used in the frame of scaling time series analysis, can be used also in 2D. The main advantage of this method is that it can be applied to process images which have missing data. Based on both simulated and real images, we demonstrate that coarse-graining (CG) of a gradient modulus transform of the original image does not provide correct scaling exponents. We show, using a fractional Brownian simulation in 2D, that the structure function (SF) can be used with randomly sampled couple of points, and verify that 1 million of couple of points provides enough statistics.

[Vancomycin-induced DRESS syndrome: a case report]. / DRESS (Drug reaction with eosinophilia and systemic symptoms) suite à la prise de vancomycine : à propos d'un cas.

DRESS syndrome is a severe adverse drug-induced reaction, characterized by generalized skin rash associated with hypereosinophilia, lymphocytosis and internal organ involvement. Antiepileptics, sulfamides and allopurinol are the most frequently reported drugs; vancomycin is less common. We report a case of vancomycin-induced DRESS syndrome in a 69-year-old male patient. Clinical symptoms and diagnosis difficulties are reported through this observation as well as pathogenesis and treatment of this syndrom.