Development of a motorized cryovalve for the control of superfluid liquid helium

Recent advances in the technology of infrared detectors have made possible a wide range of scientific measurements and investigations. One of the requirements for the use of sensitive IR detectors is that the entire instrument be cooled to temperatures approaching absolute zero. The cryogenic cooling system for these instruments is commonly designed as a large dewar containing liquid helium which completely surrounds the apparatus. Thus, there is a need for a remotely controlled, motorized cryovalve that is simple, reliable, and compact and can operate over extended periods of time in cryo-vac conditions. The design, development, and test of a motorized cryovalve with application to a variety of cryogenic systems currently under development is described

Fracture properties characterization of nuclear fuel using micro-cantilever bending

International audienc

Proof of concept car adsorption air conditioning system using a compact sorption reactor

A prototype compact sorption generator using an activated-carbon ammonia pair based on a plate heat exchanger concept has been designed and built at Warwick University. The novel generator has low thermal mass and good heat transfer. The heat exchanger uses Nickel brazed shims and spacers to create adsorbent layers only 4 mm thick between pairs of liquid flow channels of very low thermal mass. The prototype sorption generator manufactured has been evaluated under the EU car air conditioning testing conditions. While driven with waste heat from the engine coolant water (at 90°C), a pair of the current prototype generators (loaded with about 1 kg of a carbon in each of two beds) has produced an average cooling power of 1.6 kW with 2 kW peaks

Assessment of treatment outcomes of multidrug-resistant tuberculosis patients in D R Congo: A study based on drug regimens used between 2007 to 2017: Évaluation des issues thérapeutiques des patients atteints de la tuberculose à bacilles multi résistants : étude basée sur les régimes de médicaments utilisés en République Démocratique du Congo de 2007 à 2017

Context. Little is known about therapeutic successes in MDR-TB patients under regimens containing second-line molecules. The present study aimed to assess therapeutic outcomes in patients under therapeutic regimens applied in DR Congo. Methods. This historical cohort study has included confirmed MDR-TB patients who received treatment between 2007 and 2017 in 218 TB centers in DR Congo. Treatment outcome and survival at 36 months were analyzed using Zscore and chi square test. Kaplan-Meier method was performed to describe survival and Log Rank test helped in comparing curve based on the therapeutical regimen. Factors associated with therapeutic success and mortality predictors were assessed using multivariate logistic regression and Cox regression analysis, respectively. Results. The therapeutic success in the study group (n=1,724) was 72% (range 68-74%) for all regimen combined. The average death rate was 12.8% although the group of patients receiving Cyclosérine and Ofloxacine was the most affected (16%). The death rate was significantly higher in patients living in urban areas (15.2% versus 14.9%, p = 0.013) and also among MDR-TB/HIV co-infected patients (28.4% vs 15.7%, p<0.001) patients. The median survival of the study group was 722.7 days compared to 601.1 days for MDR-TB/HIV co-infected patients, and 736.7 days for HIV negative patients (p<0.001). Conclusion. Therapeutic successes are significant for the short regimen. However, the death rate remains high when Cycloserine and Ofloxacin are included in the regimen. The predictors of mortality are HIV infection and living in urban areas. Contexte. L’issue thérapeutique de la tuberculose multi résistante (TB-MR) sous les molécules de deuxième intention n’est pas très bien connue. La présente étude a évalué les régimes thérapeutiques appliqués, en termes de succès thérapeutique et de survie. Méthodes. L’étude de cohorte historique a inclu les patients TB-MR confirmés et traités entre 2007 et 2017 dans 218 centres de tuberculose en RD Congo. L’issue thérapeutique et la survie à 36 mois ont été analysées. Le score Z ou le test de chi carré ont comparé des issues. La méthode de Kaplan-Meier a décrit les courbes de survie et le test de Log Rank a comparé la survie en fonction du regime therapeutique. Les facteurs associés au succès thérapeutique et les prédicteurs de mortalité ont été analysés respectivement, par l’analyse multivariée de régression logistique et de Cox. Résultats. Dans le groupe étudié (n=1724), le succès thérapeutique a été de 72% (68-74%) pour l’ensemble des régimes. Le taux était plus élevé pour le régime court (74%) et plus faible pour le régime contenant la Cyclosérine et l’Ofloxacine (68%). La moyenne de décès était de 12,8% ; mais plus élevée dans le groupe sous regime contenant la Cyclosérine et l’Ofloxacine (16%). Le taux de décès était significativement plus élevé en milieu urbain (15,2% versus 14,9 %, p = 0,013) et également chez les sujets co-infectés par la MDR-TB  et le VIH (28.4% vs 15.7%, p <0,001). La survie médiane dans le groupe était de 722,7 jours contre 601,1 jours chez les co-infectés MDR-TB/VIH, et de 736,7 jours) chez les patients VIH négatifs (p<0,001). Conclusion. Les succès thérapeutiques sont acceptables en particulier, pour le régime court ; toutefois, le taux de décès demeure encore très élevé dans le groupe sous Cyclosérine et Ofloxacine. Les prédicteurs de mortalité sont l’infection à VIH et la vie citadine. &nbsp

Toward Forecasting Volcanic Eruptions using Seismic Noise

During inter-eruption periods, magma pressurization yields subtle changes of the elastic properties of volcanic edifices. We use the reproducibility properties of the ambient seismic noise recorded on the Piton de la Fournaise volcano to measure relative seismic velocity variations of less than 0.1 % with a temporal resolution of one day. Our results show that five studied volcanic eruptions were preceded by clearly detectable seismic velocity decreases within the zone of magma injection. These precursors reflect the edifice dilatation induced by magma pressurization and can be useful indicators to improve the forecasting of volcanic eruptions.Comment: Supplementary information: http://www-lgit.obs.ujf-grenoble.fr/~fbrengui/brenguier_SI.pdf Supplementary video: http://www-lgit.obs.ujf-grenoble.fr/~fbrengui/brenguierMovieVolcano.av

Updated observing scenarios and multi-messenger implications for the International Gravitational-wave Network's O4 and O5

Advanced LIGO and Virgo's third observing run brought another binary neutron star merger (BNS) and the first neutron-star black-hole (NSBH) mergers. While no confirmed kilonovae (KNe) was identified in conjunction with any of these events, continued improvements of analyses surrounding GW170817 allow us to project constraints on the Hubble Constant ($H_0$), the Galactic enrichment from $r$-process nucleosynthesis, and ultra-dense matter possible from forthcoming events. Here, we describe the expected constraints based on the latest expected event rates from the international gravitational-wave network (IGWN) and analyses of GW170817. We show the expected detection rate of gravitational waves and their counterparts, as well as how sensitive potential constraints are to the observed numbers of counterparts. We intend this analysis as support for the community when creating scientifically-driven electromagnetic follow-up proposals. During the next observing run O4, we predict an annual detection rate of electromagnetic counterparts from BNS of $0.43^{+0.58}_{-0.26}$ ($1.97^{+2.68}_{-1.2}$) for the Zwicky Transient Facility (Rubin Observatory)

Farmers' perceptions on mechanical weeders for rice production in sub-Saharan Africa

Competition from weeds is one of the major biophysical constraints to rice (Oryza spp.) production in sub-Saharan Africa. Smallholder rice farmers require efficient, affordable and labour-saving weed management technologies. Mechanical weeders have shown to fit this profile. Several mechanical weeder types exist but little is known about locally specific differences in performance and farmer preference between these types. Three to six different weeder types were evaluated at 10 different sites across seven countries – i.e., Benin, Burkina Faso, Côte d'Ivoire, Ghana, Nigeria, Rwanda and Togo. A total of 310 farmers (173 male, 137 female) tested the weeders, scored them for their preference, and compared them with their own weed management practices. In a follow-up study, 186 farmers from Benin and Nigeria received the ring hoe, which was the most preferred in these two countries, to use it during the entire crop growing season. Farmers were surveyed on their experiences. The probability of the ring hoe having the highest score among the tested weeders was 71%. The probability of farmers’ preference of the ring hoe over their usual practices – i.e., herbicide, traditional hoe and hand weeding – was 52, 95 and 91%, respectively. The preference of this weeder was not related to gender, years of experience with rice cultivation, rice field size, weed infestation level, water status or soil texture. In the follow-up study, 80% of farmers who used the ring hoe indicated that weeding time was reduced by at least 31%. Of the farmers testing the ring hoe in the follow-up study, 35% used it also for other crops such as vegetables, maize, sorghum, cassava and millet. These results suggest that the ring hoe offers a gender-neutral solution for reducing labour for weeding in rice as well as other crops and that it is compatible with a wide range of environments. The implications of our findings and challenges for out-scaling of mechanical weeders are discussed

Atorvastatin prevents Plasmodium falciparum cytoadherence and endothelial damage

<p>Abstract</p> <p>Background</p> <p>The adhesion of <it>Plasmodium falciparum </it>parasitized red blood cell (PRBC) to human endothelial cells (EC) induces inflammatory processes, coagulation cascades, oxidative stress and apoptosis. These pathological processes are suspected to be responsible for the blood-brain-barrier and other organs' endothelial dysfunctions observed in fatal cases of malaria. Atorvastatin, a drug that belongs to the lowering cholesterol molecule family of statins, has been shown to ameliorate endothelial functions and is widely used in patients with cardiovascular disorders.</p> <p>Methods</p> <p>The effect of this compound on PRBC induced endothelial impairments was assessed using endothelial co-culture models.</p> <p>Results</p> <p>Atorvastatin pre-treatment of EC was found to reduce the expression of adhesion molecules and <it>P. falciparum </it>cytoadherence, to protect cells against PRBC-induced apoptosis and to enhance endothelial monolayer integrity during co-incubation with parasites.</p> <p>Conclusions</p> <p>These results might suggest a potential interest use of atorvastatin as a protective treatment to interfere with the pathophysiological cascades leading to severe malaria.</p

Inhibition of Plasmodium falciparum Field Isolates-Mediated Endothelial Cell Apoptosis by Fasudil: Therapeutic Implications for Severe Malaria

Plasmodium falciparum infection can abruptly progress to severe malaria, a life-threatening complication resulting from sequestration of parasitized red blood cells (PRBC) in the microvasculature of various organs such as the brain and lungs. PRBC adhesion can induce endothelial cell (EC) activation and apoptosis, thereby disrupting the blood-brain barrier. Moreover, hemozoin, the malarial pigment, induces the erythroid precursor apoptosis. Despite the current efficiency of antimalarial drugs in killing parasites, severe malaria still causes up to one million deaths every year. A new strategy targeting both parasite elimination and EC protection is urgently needed in the field. Recently, a rho-kinase inhibitior Fasudil, a drug already in clinical use in humans for cardio- and neuro-vascular diseases, was successfully tested on laboratory strains of P. falciparum to protect and to reverse damages of the endothelium. We therefore assessed herein whether Fasudil would have a similar efficiency on P. falciparum taken directly from malaria patients using contact and non-contact experiments. Seven (23.3%) of 30 PRBC preparations from different patients were apoptogenic, four (13.3%) acting by cytoadherence and three (10%) via soluble factors. None of the apoptogenic PRBC preparations used both mechanisms indicating a possible mutual exclusion of signal transduction ligand. Three PRBC preparations (42.9%) induced EC apoptosis by cytoadherence after 4 h of coculture (“rapid transducers”), and four (57.1%) after a minimum of 24 h (“slow transducers”). The intensity of apoptosis increased with time. Interestingly, Fasudil inhibited EC apoptosis mediated both by cell-cell contact and by soluble factors but did not affect PRBC cytoadherence. Fasudil was found to be able to prevent endothelium apoptosis from all the P. falciparum isolates tested. Our data provide evidence of the strong anti-apoptogenic effect of Fasudil and show that endothelial cell-P. falciparum interactions are more complicated than previously thought. These findings may warrant clinical trials of Fasudil in severe malaria management