Forme d'azote à la croissance, à l'embryogenèe et à la régénération des cals de blé (Triticum aestivum L.)

L'effet de la forme d'azote dans le milieu de culture (ammoniacal, nitrique, organique ou différentes combinaisons) sur les capacités embryogènes des cals de blé a été étudié. Les molécules azotées habituelles du milieu Murashige & Skoog (1962) sont remplacées par un mélange de KN03 (30 mM) et de NaN03 (30 mM) dans le cas de l'azote nitrique, par du NH4CI (20 mM) additionné de (NH4hS04 (20 mM) quand l'azote est ammonical ou par la glutamine (800 mgll), la sérine (100 mg/l) et l'hydrolysat de caséine (100 mgll) lorsque l'azote est organique. Apporté sous forme ammoniacale seule, organique seule, ou sous forme combinée, l'azote n'a favorisé ni la croissance du cal ni l'embryogenèse somatique. Par contre, l'utilisation de l'azote nitrique comme seule source d'azote a stimulé beaucoup plus l'embryogenèse somatique que la croissance du cal. Une embryogenèse somatique normale a été observée lorsque l'azote nitrique a été combiné à l'azote organique. Une influence nette de la forme de l'azote sur le pH, la salinité et la conductivité électrique du milieu de culture a été observée. La fragmentation réduit significativement la germination des embryons zygotiques mis en culture mais a peu d'influence sur l'embryogenèse somatique.Nitrogen composition and embryogenesis in wheat caHus (Triticum aestivum L.)The effect of different forms of nitrogen in the culture medium (ammonia, nitrate, organic compounds or their combinations) on the embryogenic capacity of wheat callus has been studied. The nitrogen molecules of the Murashige & Skoog (1962) medium were replaced by a combination ofKN03 (30 mM) and NaN03 (30 mM) for nitrogen in nitrate form, by NH4Cl (20 mM) and (NH4)2S04 (20 mM) for nitrogen in ammonical form, or by glutamine (800 mg/l), serine (100 mgll) and casein hydrolysate (100 mg/l) in the case of organic nitrogen. The ammoniacal form alone, organic form alone or their combination promoted neither caHus growth nor somatic embryogenesis. However, the use of nitrates as the unique nitrogen source enhanced embryogenesis more than callus growth. Normal embryogenesis has been observed when nitrates were combined with organic nitrogen. A clear influence of the nitrogen form on culture medium pH, salinity and electric conductivity and consequently on the embryogenic potential of the cultures, was shown. Fragmentation of the zygotic embryo (before culture) significantly reduced zygotic germination, but had only little effect on somatic embryogenesis

Assessment of Antioxidant and Antibacterial Activities of Cystoseira mediterranea and Padina pavonica from Algerian North-East for a Potential Use as a Food Preservative

The aim of this work was to evaluate the antioxidant and antibacterial activities of two marine algae, Cystoseira mediterranea and Padina pavonica, extracts. Total phenols (TPC), carotenoids, and phlorotannins contents of the extracts obtained by four extraction solvents were determined and compared. The highest TPC content was observed for aqueous extract of C. mediterranea with 37.09±0.46 mg GAE/g DE followed by ethanol extract of P. pavonica (24.28±0.99 mg GAE/g DE), which showed the highest phlorotannins content (1.18±0.18 mg PE/g DE), while its methanol extract held carotenoids content of 66.96±4.78 μg g–1 DE. Ethanol extract of C. mediterranea exhibited the best antioxidant activity with an EC50 of 58.3±1.16 μg ml–1. The antibacterial activity screening against MRSA and E. coli showed that ethanol extract of C. mediterranea towards a Methicillin resistant Staphyloccocus aureus (20.33±0.28 mm) and E. coli (15.66±0.57 mm) was more efficient with MICs about 80 mg ml–1 and 20 mg ml–1, respectively. Ethanol extract of C. mediterranea seems to have the highest potential for use in food industries

Approche cinétique appliquée aux milieux poreux : cas des membranes de filtration

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Contrôle de la génération d´harmoniques d´ordres élevés par modulation de l´ellipticité du fondamental

International audienceNous présentons les résultats de deux campagnes expérimentales, étudiant le confinement temporel de la génération d'harmoniques d'ordres élevés par modulation de l'ellipticité du champ fondamental. Une première expérience réalisée au LLC (Lund Laser Center) valide cette technique de « porte d'ellipticité » dans le régime femtoseconde et nous permet par une mesure temporelle directe de comparer la durée de l'émission XUV avec la durée calculée de la porte d'ellipticité. Une seconde expérience réalisée au CELIA met en évidence unéelargissement spectral des harmoniques jusqu'à l'obtention d'un quasi-continuum. Ce quasicontinuum est théoriquement consistant avec l'émission d'une impulsion ou de deux impulsions attosecondes selon la phase absolue du champ fondamental

Shaping of attosecond pulses by phase-stabilized polarization gating

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Experimental studies of attosecond pulse trains

We present experimental measurements of attosecond pulse trains. The characterization of the pulses uses a spectral interferometry technique that is implemented with a Mach-Zehnder interferometer. This allows us to manipulate independently the pump and probe pulses for a wide range of applications. By letting the attosecond pulses pass through metallic films, we can in particular compensate for the intrinsic chirp of the attosecond pulses corresponding to the plateau spectral region, thus getting pulses as short as 170 attoseconds- only 1.2 optical cycles at the central frequency. The measurement technique is also applicable for determination of the group delay of thin XUV-transparent films and relative delay in the photoionization process. Our experimental method is applied to attosecond pulse trains created by 35- and 9-fs laser pulses, and the shortest train observed consists of three or four pulses

Evaluation of the routine implementation of pulse oximeters into integrated management of childhood illness (IMCI) guidelines at primary health care level in West Africa : the AIRE mixed-methods research protocol

Background: The AIRE operational project will evaluate the implementation of the routine Pulse Oximeter (PO) use in the integrated management of childhood illness (IMCI) strategy for children under-5 in primary health care centers (PHC) in West Africa. The introduction of PO should promote the accurate identification of hypoxemia (pulse blood oxygen saturation Sp02 < 90%) among all severe IMCI cases (respiratory and non-respiratory) to prompt their effective case management (oxygen, antibiotics and other required treatments) at hospital. We seek to understand how the routine use of PO integrated in IMCI outpatients works (or not), for whom, in what contexts and with what outcomes.Methods: The AIRE project is being implemented from 03/2020 to 12/2022 in 202 PHCs in four West African countries (Burkina Faso, Guinea, Mali, Niger) including 16 research PHCs (four per country). The research protocol will assess three complementary components using mixed quantitative and qualitative methods: a) context based on repeated cross-sectional surveys: baseline and aggregated monthly data from all PHCs on infrastructure, staffing, accessibility, equipment, PO use, severe cases and care; b) the process across PHCs by assessing acceptability, fidelity, implementation challenges and realistic evaluation, and c) individual outcomes in the research PHCs: all children under-5 attending IMCI clinics, eligible for PO use will be included with parental consent in a cross-sectional study. Among them, severe IMCI cases will be followed in a prospective cohort to assess their health status at 14 days. We will analyze pathways, patterns of care, and costs of care.Discussion: This research will identify challenges to the systematic implementation of PO in IMCI consultations, such as health workers practices, frequent turnover, quality of care, etc. Further research will be needed to fully address key questions such as the best time to introduce PO into the IMCI process, the best SpO2 threshold for deciding on hospital referral, and assessing the cost-effectiveness of PO use. The AIRE research will provide health policy makers in West Africa with sufficient evidence on the context, process and outcomes of using PO integrated into IMCI to promote scale-up in all PHCs.Trial registration: Trial registration number: PACTR202206525204526 retrospectively registered on 06/15/202

Characterization of Autosomal Dominant Hypercholesterolemia Caused by PCSK9 Gain of Function Mutations and its Specific Treatment with Alirocumab, a PCSK9 Monoclonal Antibody

BACKGROUND: Patients with PCSK9 gene gain of function (GOF) mutations have a rare form of autosomal dominant hypercholesterolemia. However, data examining their clinical characteristics and geographic distribution are lacking. Furthermore, no randomized treatment study in this population has been reported. METHODS AND RESULTS: -We compiled clinical characteristics of PCSK9 GOF mutation carriers in a multinational retrospective, cross-sectional, observational study. We then performed a randomized placebo-phase, double-blind study of alirocumab 150 mg administered subcutaneously every 2 weeks to 13 patients representing four different PCSK9 GOF mutations with low-density lipoprotein cholesterol (LDL-C) >70 mg/dL on their current lipid-lowering therapies at baseline. Observational study: Among 164 patients, 16 different PCSK9 GOF mutations distributed throughout the gene were associated with varying severity of untreated LDL-C levels. Coronary artery disease was common (33%; average age of onset 49.4 years) and untreated LDL-C concentrations were higher compared with matched carriers of mutations in the LDLR (n=2126) or apolipoprotein B (n=470) genes. Intervention study: In PCSK9 GOF mutation patients randomly assigned to receive alirocumab, mean percent reduction in LDL-C at 2 weeks was 62.5% (P<0.0001) from baseline, 53.7% compared to placebo-treated PCSK9 GOF mutation patients (P=0.0009; primary endpoint). After all subjects received 8 weeks of alirocumab treatment, LDL-C was reduced by 73% from baseline (P<0.0001). CONCLUSIONS: -PCSK9 GOF mutation carriers have elevated LDL-C levels and are at high risk for premature cardiovascular disease. Alirocumab, a PCSK9 antibody, markedly lowers LDL-C levels and appears to be well tolerated in these patients. Clinical Trial Registration-www.clinicaltrials.gov; Unique Identifier: NCT01604824These studies were sponsored by Regeneron Pharmaceuticals Inc. and Sanofi