Continuous flow catalysis with a biomimetic copper(II) complex covalently immobilized on graphite felt

International audienceThe catecholase activity of a copper(II) complex coordinated by a tripodal pyrazole-based ligand was investigated in continuous flow catalysis. The covalent immobilization of the complex on the surface was achieved by a two steps method. First, the porous graphite felt support is functionalized by electrochemical reduction of 4-carboxymethyl-benzenediazonium salts. Second, the complex is covalently immobilized by esterification reaction between the COOH-containing linker and a primary alcohol group present on the C6 chain of the ligand. The two steps of the immobilization process were optimized by using nitro-containing molecules and cyclic voltammetry analyses. The copper complex exhibits higher catecholase activity in continuous flow catalysis than in solution with a 50 times lower amount of catalyst, underlining the advantages of the flow procedure. The presence of H2O2 is detected after catalysis, showing that the four-electron reduction of dioxygen to water does not occur unlike the natural enzyme

Impact of nature and length of linker on the catecholase activity of a covalently immobilized copper(II) complex in continuous flow catalysis

International audienceThe catecholase activity of four immobilized mononuclear copper(II) catalysts with chains of different nature and length used as linkers is studied in continuous flow catalysis. The graphite felt support was first derivatized by cathodic reduction of 4-carboxymethyl-benzenediazonium salts. Complexes with different chains were then covalently immobilized on the functionalized porous support by esterification reaction. The successful achievement of the immobilization process is attested by the presence of the CuII/I reversible system in cyclic voltammetry. Volume concentrations around 10−8 mol cm−3 of immobilized catalysts are estimated by integration of the redox peak. Comparison of the catecholase activity of the immobilized complexes allows to conclude on the effect of the chain nature and length. First, high chain length positively influences the catalytic activity. Second, the presence of oxygen atoms in the linker significantly enhances the catecholase activity of the catalyst. A possible explanation is the chain hydrophilicity, making easier the access of the catalytic center by H2O molecules

Isolation of a Novel Phage with Activity against Streptococcus mutans Biofilms

peer-reviewedStreptococcus mutans is one of the principal agents of caries formation mainly, because of its ability to form biofilms at the tooth surface. Bacteriophages (phages) are promising antimicrobial agents that could be used to prevent or treat caries formation by S. mutans. The aim of this study was to isolate new S. mutans phages and to characterize their antimicrobial properties. A new phage, ɸAPCM01, was isolated from a human saliva sample. Its genome was closely related to the only two other available S. mutans phage genomes, M102 and M102AD. ɸAPCM01 inhibited the growth of S. mutans strain DPC6143 within hours in broth and in artificial saliva at multiplicity of infections as low as 2.5x10-5. In the presence of phage ɸAPCM01 the metabolic activity of a S. mutans biofilm was reduced after 24 h of contact and did not increased again after 48 h, and the live cells in the biofilm decreased by at least 5 log cfu/ml. Despite its narrow host range, this newly isolated S. mutans phage exhibits promising antimicrobial properties

The study of Hydrography at French institutes ENSTA Bretagne, Cnam/Intechmer and Shom/UBO

Every year, around 60 highly-qualified hydrographers graduate from the French institutions ENSTA Bretagne, Cnam Intechmer and Shom/UBO. These complementary teachings address both civilian and military demands. The survey practice is a key part of the training which ensure students’ ability to be quickly operational in the professional world. This paper outlines major fieldwork conducted by each school, where trainees acquire technical skills. To face these growing needs in terms of staff and equipment, French facilities actively cooperate. In particular, there are some bridges between educational programmes and also more global expertise and materials sharing.Les établissements français à savoir l’ENSTA Bretagne, Cnam Intechmer et le Shom/UBO forment chaque année une soixantaine d’hydrographes. Ces formations complémentaires répondent à la fois aux besoins civils et militaires. La composante pratique de la formation est fondamentale pour rendre ces futurs diplômés rapidement opérationnels dans le monde du travail. Ce papier présente un projet terrain d’envergure propre à chaque école dans lequel les étudiants développent leurs expertises techniques. Pour faire face aux besoins importants tant en termes d’encadrement que de matériel, les instituts collaborent activement entre eux. Il existe ainsi des passerelles inter-établissements sur la formation, et des partages de compétence sur les enjeux actuels et futurs de l’hydrographieJedes Jahr schließen rund 60 hochqualifizierte Hydrographen ihre Ausbildung an den französischen Institutionen ENSTA Bretagne, Cnam Intechmer und Shom/UBO ab. Diese sich ergänzenden Ausbildungen decken sowohl den zivilen als auch den militärischen Bedarf ab. Die Vermessungspraxis ist ein zentraler Bestandteil der Ausbildung, um die Studierenden schnell in der Berufswelt einsetzen zu können. In diesem Paper werden die wichtigsten von den einzelnen Schulen durchgeführten Feldarbeiten beschrieben, bei denen die Studierenden technische Fähigkeiten erwerben. Um den hohen Bedarf an Personal und Ausrüstung zu decken, arbeiten die französischen Einrichtungen aktiv zusammen. Insbesondere gibt es einige Brücken zwischen Bildungsprogrammen und auch einen globaleren Austausch von Fachwissen und Materialien

Rate enhancement of the catechol oxidase activity of a series of biomimetic monocopper(II) complexes by introduction of non-coordinating groups in N-tripodal ligands

International audienceAsymmetrical N-tripodal ligands have been synthesized in three steps. Diversity has been introduced at the first step of the synthesis by adding pyrazine, pyridine, benzyl and thiophene rings. The corresponding CuII complexes have been prepared by reaction with CuCl2 and characterized by Electron Paramagnetic Resonance (EPR), UV-Vis spectroscopies and cyclic voltammetry. The data show that the ligand coordinates to CuII in a mononuclear fashion in solution and that the complexes display a square pyramidal geometry. All complexes are characterized by a quasi-reversible one-electron redox behavior in acetonitrile. The ability of the complexes to oxidize 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone has been studied and the results show that the rate of the reaction depends on the basicity and the steric hindrance of the heterocyclic donor. Best results have been obtained with CuII complexes coordinated to bidentate ligands, since they facilitate the approach and the coordination of catechol to the metal. Particularly, the introduction of a thiophenyl group to mimic the sulfur atom at proximity to the catalytic center in the catechol oxidase protein structure improves the catalytic activity of the complex

Evidence for different patterns of chemosensory alterations in the elderly population: impact of age versus dependency

The present experiment aimed to explore the interindividual variability in chemosensory abilities among the elderly population. The chemosensory abilities of 559 subjects, aged from 65 to 99 years, were evaluated. Various categories of the elderly, including people who were living at home either without or with assistance, and people who were living in a nursing home, were interviewed. The results revealed that 43% of the sample presented well-preserved chemosensory abilities, whereas 21% of the participants presented a moderate impairment. Of the sample, 33% presented well-preserved olfactory abilities but strong impairment in gustatory abilities and 3% were nearly anosmic but remained able to perceive the salty taste, demonstrating that gustation and olfaction were not systematically damaged simultaneously. The results showed a link between the level of dependence (free living vs. living at home with help vs. nursing home) and chemosensory abilities, independently of the age effect. These results strengthen the hypothesis that the impairment of chemosensory abilities is not only an effect of age per se; rather, it is related to events that are associated with aging. Factors that lead to increased dependence (such as poor health) also lead to an impairment in chemosensory performance

Drug prescriptions and dementia incidence: a medication-wide association study of 17000 dementia cases among half a million participants

Previous studies have suggested that some medications may influence dementia risk. We conducted a hypothesis-generating medication-wide association study to investigate systematically the association between all prescription medications and incident dementia. We used a population-based cohort within the Secure Anonymised Information Linkage (SAIL) databank, comprising routinely-collected primary care, hospital admissions and mortality data from Wales, UK. We included all participants born after 1910 and registered with a SAIL general practice at ≤60 years old. Follow-up was from each participant's 60th birthday to the earliest of dementia diagnosis, deregistration from a SAIL general practice, death or the end of 2018. We considered participants exposed to a medication if they received ≥1 prescription for any of 744 medications before or during follow-up. We adjusted for sex, smoking and socioeconomic status. The outcome was any all-cause dementia code in primary care, hospital or mortality data during follow-up. We used Cox regression to calculate hazard ratios and Bonferroni-corrected p values. Of 551 344 participants, 16 998 (3%) developed dementia (median follow-up was 17 years for people who developed dementia, 10 years for those without dementia). Of 744 medications, 221 (30%) were associated with dementia. Of these, 217 (98%) were associated with increased dementia incidence, many clustering around certain indications. Four medications (all vaccines) were associated with a lower dementia incidence. Almost a third of medications were associated with dementia. The clustering of many drugs around certain indications may provide insights into early manifestations of dementia. We encourage further investigation of hypotheses generated by these results. [Abstract copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.

Interventions to enhance adherence to medications in patients with heart failure: a systematic review

First paragraph: Prognosis remains poor for patients with chronic heart failure (CHF), despite improvements in the prevention and treatment of heart failure over the last 25 years. Recent estimates indicate that the median survival after a first episode of heart failure is 2.3 years for men and 1.8 years for women. It is suggested that the improvements in outcomes that have been achieved can be partly explained by increases in prescribing rates of medications such as angiotensin-converting enzyme inhibitors, β-blockers, and spironolactone over this period. Although the evidence on medication efficacy for certain subgroups of patients with CHF is clear, there are also compelling data showing that many of these patients do not take their medications as prescribed by health care providers. This "nonadherence" to medication therefore remains a significant barrier to enhancing the effectiveness of existing treatments

Three New Escherichia coli Phages from the Human Gut Show Promising Potential for Phage Therapy

peer-reviewedWith the emergence of multi-drug resistant bacteria the use of bacteriophages (phages) is gaining renewed interest as promising anti-microbial agents. The aim of this study was to isolate and characterize phages from human fecal samples. Three new coliphages, ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03, were isolated. Their phenotypic and genomic characteristics, and lytic activity against biofilm, and in combination with ciprofloxacin, were investigated. All three phages reduced the growth of E. coli strain DPC6051 at multiplicity of infection (MOI) between 10−3 and 105. A cocktail of all three phages completely inhibited the growth of E. coli. The phage cocktail also reduced biofilm formation and prevented the emergence of phage-resistant mutants which occurred with single phage. When combined with ciprofloxacin, phage alone or in cocktail inhibited the growth of E. coli and prevented the emergence of resistant mutants. These three new phages are promising biocontrol agents for E. coli infections

Collecting and utilising crowdsourced data for numerical weather prediction: propositions from the meeting held in Copenhagen, 4–December 5, 2018

In December 2018, the Danish Meteorological Institute organised an international meeting on the subject of crowdsourced data in numerical weather prediction (NWP) and weather forecasting. The meeting, spanning 2 days, gathered experts on crowdsourced data from both meteorological institutes and universities from Europe and the United States. Scientific presentations highlighted a vast array of possibilities and progress being made globally. Subjects include data from vehicles, smartphones, and private weather stations. Two groups were created to discuss open questions regarding the collection and use of crowdsourced data from different observing platforms. Common challenges were identified and potential solutions were discussed. While most of the work presented was preliminary, the results shared suggested that crowdsourced observations have the potential to enhance NWP. A common platform for sharing expertise, data, and results would help crowdsourced data realise this potential