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

Etude de l'empoussièrement des poudres par un test de fluidisation

National audienceThe aim of this study is to use a fluidized bed as a dustiness test based on entrainment and elutriation phenomena for a reconstructed model system. Once the operating conditions were identified, a simple phenomenological model was established, able to predict the amount of dust initially present in a mixture. In order to do that, a parametric study was conducted with bimodal powder mixtures. Thus, large particles simulate the powder and the fine dust. The experimental study was carried out with Geldart A and C particles, in a fluidized bed. Furthermore, the influence of some intrinsic and extrinsic parameters of the bulk on the dust emission was studied. Subsequently, different models present in the literature were tested in order to predict the dustiness. This comparison allowed choosing the model of Santana et al. (1999) which showed a better match with the results of this study.L'objectif de ce travail est d'utiliser un lit fluidisé comme test d'empoussièrement en se basant sur les phénomènes d'entraînement et d'élutriation pour un système modèle reconstitué. Suite à l'identification des conditions opératoires, un modèle phénoménologique simple capable de prédire la quantité de poussière initialement présente dans un mélange, a été établit. Une étude paramétrique a été réalisée avec des mélanges de poudres et de poussières de tailles différentes ; ainsi, les grosses particules simuleront la poudre et les fines les poussières. Par ailleurs, nous avons étudié l'influence de certains paramètres intrinsèques du mélange sur l'empoussièrement et testé différents modèles rencontrés dans la littérature permettant de prédire l'empoussièrement. Cette comparaison a permis de choisir le modèle de Santana et al. (1999) qui a montré une meilleure adéquation avec les résultats de cette étude

Extracting inter-arrival time based behaviour from honeypot traffic using cliques

The Leurre.com project is a worldwide network of honeypot environments that collect traces of malicious Internet traffic every day. Clustering techniques have been utilized to categorize and classify honeypot activities based on several traffic features. While such clusters of traffic provide useful information about different activities that are happening in the Internet, a new correlation approach is needed to automate the discovery of refined types of activities that share common features. This paper proposes the use of packet inter-arrival time (IAT) as a main feature in grouping clusters that exhibit commonalities in their IAT distributions. Our approach utilizes the cliquing algorithm for the automatic discovery of cliques of clusters. We demonstrate the usefulness of our methodology by providing several examples of IAT cliques and a discussion of the types of activity they represent. We also give some insight into the causes of these activities. In addition, we address the limitation of our approach, through the manual extraction of what we term supercliques, and discuss ideas for further improvement

Ebola virus outbreak returns to the Democratic Republic of Congo:An urgent rising concern

On April 23, 2022, the Ministry of Health of the Democratic Republic of the Congo announced an EVD outbreak after discovering 2 confirmed cases and identifying 267 contacts. With collaboration from the WHO, the MoH are taking many interventions to prevent further expansion of this outbreak. Forty-six years ago, the Ebola virus was first discovered in 1976 near the Ebola River in the DRC. Since then, 13 outbreaks of EVD have occurred in the DRC and, in 2020, it witnessed the second largest EVD outbreak in the world, resulting in 3481 cases and 2299 mortalities. This article discusses the epidemiology of the current DRC outbreak by examining the etiology of EVD, the number of affected cases, and the subsequent case index. Considering these data, this paper discusses measures taken by the MoH, WHO, CDC, and UNICEF to mitigate the Ebola outbreak, such as supporting local teams to provide essential care, training medical staff, and raising awareness for vaccination. Finally, by comparing the gravity of the situation to current measures, this article provides recommendations for individuals and governments to protect themselves and mitigate future outbreaks

Hepatitis A virus outbreak in Lebanon:Is it a matter of concern?

Lebanon has been grappling with hepatitis A virus (HAV) outbreaks for 3 decades, to an extent that it has been now termed an endemic zone for HAV. However, the rise in cases above the annual average concerns a potential outbreak in the North, and the Bekaa governorates of Lebanon must be highlighted. Although the Lebanese health authorities have ordered a probe into the possible causes of the outbreak, it has been speculated that the immigration of Syrian refugees has overburdened public health services. Reduced seroprevalence of HAV immunoglobulin G has also led to an epidemiological shift from child to adult populations. The current economic crisis affecting Lebanese society is another significant problem that could have contributed to the rise in incidents. This article examines Lebanon's current HAV outbreak and epidemiological status, offering suggestions for the future. In the event of an outbreak, the infrastructure for water sanitation and sewage is known to allow HAV to spread via the faecal-oral pathway. Maintaining personal hygiene, early detection, and vaccination have all been recommended as significant regional and individual control measures

Pretransplant characteristics of kidney transplant recipients that predict posttransplant outcome

Better characterization of the potential kidney transplant recipient using novel biomarkers, for example, pretransplant plasma endotrophin, will lead to improved outcome after transplantation. This mini-review will focus on current knowledge about pretransplant recipients’ characteristics, biomarkers, and immunology. Clinical characteristics of recipients including age, obesity, blood pressure, comorbidities, and estimated survival scores have been introduced for prediction of recipient and allograft survival. The pretransplant immunologic risk assessment include histocompatibility leukocyte antigens (HLAs), anti-HLA donor-specific antibodies, HLA-DQ mismatch, and non-HLA antibodies. Recently, there has been the hope that pretransplant determination of markers can further improve the prediction of posttransplant complications, both short-term and long-term outcomes including rejections, allograft loss, and mortality. Higher pretransplant plasma endotrophin levels were independently associated with posttransplant acute allograft injury in three prospective European cohorts. Elevated numbers of non-synonymous single-nucleotide polymorphism mismatch have been associated with increased allograft loss in a multivariable analysis. It is concluded that there is a need for integration of clinical characteristics and novel molecular and immunological markers to improve future transplant medicine to reach better diagnostic decisions tailored to the individual patient

Leptospirosis outbreak in Tanzania:An alarming situation

On July 5, 2022, the Tanzanian Ministry of Health (MoH) announced the re-emergence of leptospirosis after reporting 20 confirmed symptomatic cases and 3 mortalities. Leptospirosis is caused by a spirochete bacterium that lives in an animal's renal tubule and spreads to individuals through contact with contaminated animal urine. Unsupervised agricultural practices, urban development, wildlife infiltration, and a lack of sanitation have all been proposed as potential environmental causes of the present outbreak. The MoH is taking the necessary steps to halt the spread of said outbreak with assistance from the World Health Organization (WHO). This article examines the risk factors, etiology, number of confirmed cases, and subsequent case index to analyse the epidemiology of the current leptospirosis outbreak in Tanzania's southern Linda region. In light of these findings, this research further details recent recommendations made by the WHO, Centers for Disease Control and Prevention, and MoH to mitigate such an alarming situation. These recommendations include early detection and isolation, contact tracing, and chemoprophylaxis using doxycycline. The article concludes by outlining suggestions for individuals and governments, including the launch of public awareness campaigns, immunisation, increased surveillance, rapid detection testing, and the installation of suitable purification systems, to help contain future leptospirosis outbreaks

Making fair choices on the path to universal health coverage: applying principles to difficult cases

Progress towards Universal Health Coverage (UHC) requires making difficult trade-offs. In this journal, Dr. Margaret Chan, the WHO Director-General, has endorsed the principles for making such decisions put forward by the WHO Consultative Group on Equity and UHC. These principles include maximizing population health, priority for the worse off, and shielding people from health-related financial risks. But how should one apply these principles in particular cases and how should one adjudicate between them when their demands conflict? This paper by some members of the Consultative Group and a diverse group of health policy professionals addresses these questions. It considers three stylized versions of actual policy dilemmas. Each of these cases pertains to one of the three principal dimensions of progress towards UHC: which services to cover first, which populations to prioritize for coverage, and how to move from out-of-pocket expenditures to pre-payment with pooling of funds. Our cases are simplified to highlight common trade-offs. While we make specific recommendations, our primary aim is to demonstrate both the form and substance of the reasoning involved in striking a fair balance between competing interests on the road to UHC

Three Case Studies in Making Fair Choices on the Path to Universal Health Coverage

The goal of achieving Universal Health Coverage (UHC) can generally be realized only in stages. Moreover, resource, capacity and political constraints mean governments often face difficult trade-offs on the path to UHC. In a 2014 report, Making fair choices on the path to UHC, the WHO Consultative Group on Equity and Universal Health Coverage articulated principles for making such trade-offs in an equitable manner. We present three case studies which illustrate how these principles can guide practical decision-making. These case studies show how progressive realization of the right to health can be effectively guided by priority-setting principles, including generating the greatest total health gain, priority for the worse off, and financial risk protection. They also demonstrate the value of a fair and accountable process of priority setting