Schmitt Trigger Using a Self-Healing Ionic Liquid Gated Transistor

Electrical double layer transistors using ionic liquids as the gate and ZnO as the semiconductor exhibit stable operation in the presence of redox active additives. The characteristics of the device enable single components with the response of a Schmitt trigger

PROTOSCREEN - Screening and identification of active natural molecules towards Toxoplasma gondii and other protozoan of medical interest

Toxoplasma gondii, Neospora caninum et Plasmodium falciparum sont des parasites protozoaires intracellulaires obligatoires, respectivement responsables de la toxoplasmose, de la néosporose et du paludisme. Les différents traitements mis en œuvre reposent sur une association médicamenteuse. Cependant, des échecs thérapeutiques et des résistances aux traitements ont été décrits. Notre travail a porté sur l’identification de molécules actives isolées par Chomatographie de Partage Centrifuge (CPC) à partir d’extraits d’écorces d’Anogeissus leiocarpus, un arbre d’Afrique de l’ouest connu pour son activité antipaludique, et de dix arbres de la région Champagne-Ardenne. Nous nous sommes penchés, dans un premier temps, sur l’activité antiparasitaire des fractions obtenues à partir d’extrait d’écorce d’A. leiocarpus. La trachélospérogénine E et l’extrait global sans tanin se sont révélés actifs, notamment en inhibant l’invasion des cellules hôtes par T. gondii. Cet extrait a également préservé la survie des souris atteintes de toxoplasmose chronique. Les mêmes composés naturels ont eu un effet contre N. caninum et P. falciparum. Dans une seconde partie, 30 extraits d’écorces de dix arbres de la région Champagne-Ardenne ont été testés sur T. gondii et N. caninum. Les composés responsables de l’activité antiparasitaire présents chez Alnus glutinosa semblent être la bétuline et ses dérivés. Dans la dernière partie, nous nous sommes intéressés à l’activité de 400 molécules de synthèse de la Pathogen Box. Huit d’entre elles ont eu un effet significatif contre T. gondii, dont trois avec une sélectivité importante. Des expérimentations sont toutefois à réaliser pour N. caninum.Toxoplasma gondii, Neospora caninum and Plasmodium falciparum are mandatory intracellular protozoan parasites and are responsible for toxoplasmosis, neosporosis and malaria, respectively. The different treatments used are based on drug combination. However therapeutic failures and drug resistances have been described. Our work focused on the identification of active compounds isolated by Centrifugal Partition Chromatography (CPC) from crude barks extracts from Anogeissus leiocarpus, a West African tree known for its antimalarial activity, and ten trees from the Champagne-Ardenne region. First we studied the activity of the fractions obtained from the crude bark extract from A. leiocarpus. Trachelosperogenin E and the global extract without tannin showed a good activity by inhibiting host cell invasion by T. gondii. The latter was able to preserve mice survival toward chronic toxoplasmosis. These extracts were also active on N. caninum and P. falciparum. In a second part 30 crude barks extracts from ten trees located in the Champagne-Ardenne region were screened on T. gondii and N. caninum. Compounds responsible for the antiparasitic activity found in Alnus glutinosa were especially betulin and its derivatives. In the last part of this study we focused on the antiparasitic activity of 400 synthetic molecules from the Pathogen Box. Eight out of them were significantly efficient against T. gondii, among which three showed an important selectivity. Further experiments must be completed in the case of N. caninum

From Theory to Action: Good Enough Digital Preservation for Under-Resourced Cultural Heritage Institutions

Libraries, archives, museums, and other cultural heritage organizations collect, create, and steward a rapidly increasing volume of digital content. Both research conclusions and professionals’ real-life experiences expose the inherent fragility of this content. The cultural heritage and information science communities have developed guidelines, best practices, policies, procedures, and processes that can enable an organization to achieve high levels of digital preservation. However, these protocols are often complex, leaving many practitioners attempting to address the challenge of preserving digital materials feeling overwhelmed. This is particularly true for professionals serving smaller institutions that are often operating with restricted resources like small staff sizes, a lack of specialized expertise, dated technical infrastructures, and/or limited budgets. This white paper is the result of a three year investigation, funded by the Institute of Museum and Library Services, of affordable, scalable digital preservation solutions that can be successfully implemented at under-resourced organizations. It reports the results of large-scale testing of several digital preservation tools and services, suggests pragmatic digital preservation options, including an incremental approach to digital preservation practices, and asserts that communities of practice are key to success.Institute of Museum and Library Service

In Vitro and In Vivo Activity of Anogeissus leiocarpa Bark Extract and Isolated Metabolites against Toxoplasma gondii

International audienceToxoplasma gondii, belonging to the Apicomplexa phylum, is a cosmopolitan protozoan parasite that affects at least 30% of the worldʼs population. In West Africa, the leaves and bark of the tree species Anogeissus leiocarpa (DC.) Guill. & Perr. are used against zoonosis in traditional medicine and play a key role in controlling diseases induced by Apicomplexans such as malaria. In this study, extracts, fractions, and pure compounds obtained from an ethanol extract of the bark of A. leiocarpa were evaluated against T. gondii infection in vitro and in vivo. The crude bark extract showed significant activity on tachyzoites from the T. gondii RH strain (IC50 = 59.30 µg/mL). The crude bark extract without tannins and pure trachelosperogenin E purified by centrifugal partition chromatography showed the highest activity (IC50s = 12.83 and 26.63 µg/mL, respectively) with satisfying selectivity indexes of 9.61 and 9.75, respectively. The crude bark extract without tannins and pure trachelosperogenin E were able to significantly inhibit host cell invasion by the parasite in vitro, while the crude bark extract without tannins was able to increase mice survival in our murine model of chronic toxoplasmosis. These results provide new biological data for natural compounds that could enhance the current panoply of treatments against toxoplasmosis

Discovery of New Inhibitors of Toxoplasma gondii via the Pathogen Box

International audienceToxoplasma gondii is a cosmopolitan protozoan parasite which affects approximately 30% of the population worldwide. The drugs currently used against toxoplasmosis are few in number and show several limitations, such as drug intolerance, poor bioavailability, or drug resistance mechanism developed by the parasite. Thus, it is important to find new compounds able to inhibit parasite invasion or proliferation. In this study, the 400 compounds of the open-access Pathogen Box, provided by the Medicines for Malaria Venture (MMV) foundation, were screened for their anti-Toxoplasma gondii activity. A preliminary in vitro screening performed over 72 h by an enzyme-linked immunosorbent assay (ELISA) revealed 15 interesting compounds that were effective against T. gondii at 1 μM. Their cytotoxicity was estimated on Vero cells, and their 50% inhibitory concentrations (IC50) were further calculated. As a result, eight anti-Toxoplasma gondii compounds with an IC50 of less than 2 μM and a selectivity index (SI) value of greater than 4 were identified. The most active was MMV675968, showing an IC50 of 0.02 μM and a selectivity index value equal to 275. Two other compounds, MMV689480 and MMV687807, also showed a good activity against T. gondii, with IC50s of 0.10 μM (SI of 86.6) and 0.15 μM (SI of 11.3), respectively. Structure-activity relationships for the eight selected compounds also were discussed on the basis of fingerprinting similarity measurements using the Tanimoto method. The anti-Toxoplasma gondii compounds highlighted here represent potential candidates for the development of new drugs that could be used against toxoplasmosis

Structured Layer of Rhenium Dye on SiO₂ and TiO₂ Surfaces by Langmuir–Blodgett Technique

We demonstrate the Langmuir–Blodgett assembly of two rhenium–bipyridine complexes containing a flexible or an aromatic bridge, and transfer of the monolayer to SiO₂ and single crystal TiO₂ substrates. Both of the complexes (ReEC and Re2TC) have a hydrophilic carboxylic acid group, which preferentially anchors into the water subphase, and forms stable monolayers at surface pressures up to 40 mN/m. The optimum conditions for the formation of complete monolayers of both ReEC and Re2TC were identified through characterization of the morphology by atomic force microscopy (AFM), the thickness by ellipsometry, and the surface coverage by X-ray photoelectron spectroscopy (XPS). X-ray reflectivity measurements (XRR) are consistent with the orientation of the molecules normal to the substrate, and their extension to close to their calculated maximum length. Parameters derived from XRR analysis show that there is a higher packing density for Re2TC monolayers than for ReEC monolayers, attributable to the more rigid bridge in the Re2TC molecule

Investigation of antiparasitic activity of ten European tree bark extracts on Toxoplasma gondii and bioguided identification of triterpenes in Alnus glutinosa barks

International audienceToxoplasmosis is a worldwide parasitosis that affects one-third of the population. People at risk, such as immunocompromised patients (AIDS, chemotherapy treatment) or fetuses (maternal-fetal transmission) can develop severe forms of the disease. The antiparasitic activity of extracts of different polarities ( n -heptane, MeOH, MeOH/H 2 O) of ten tree species endemics to temperate regions was investigated against Toxoplasma gondii infection in vitro . Our results showed that the n -heptane extract of the black alder ( Alnus glutinosa ) exhibited a significant antiparasitic activity without any cytotoxicity at the tested concentrations, with an IC 50 of up to 25.08 μg/mL and a selectivity index higher than 3.99. The chemical profiling of this extract revealed triterpenes as major constituents. The ability of commercially available triterpene (betulin, betulinic acid, and betulone) to inhibit the growth of T. gondii was evaluated and showed growth inhibition rates of 44%, 49%, and 99% at 10 μM, respectively