Mesure des durées de vie des premiers niveaux excités du molybdène 93

Les durées de vie des six premiers niveaux excités du 93Mo ont été mesurées en utilisant l'effet Doppler associé à la réaction 93Nb(p, nγ)93Mo. Deux nouvelles durées de vie ont été obtenues et la précision des quatre autres a été améliorée

Glutathione reductase-catalyzed cascade of redox reactions to bioactivate potent antimalarial 1,4-naphthoquinones--a new strategy to combat malarial parasites.

Our work on targeting redox equilibria of malarial parasites propagating in red blood cells has led to the selection of six 1,4-naphthoquinones, which are active at nanomolar concentrations against the human pathogen Plasmodium falciparum in culture and against Plasmodium berghei in infected mice. With respect to safety, the compounds do not trigger hemolysis or other signs of toxicity in mice. Concerning the antimalarial mode of action, we propose that the lead benzyl naphthoquinones are initially oxidized at the benzylic chain to benzoyl naphthoquinones in a heme-catalyzed reaction within the digestive acidic vesicles of the parasite. The major putative benzoyl metabolites were then found to function as redox cyclers: (i) in their oxidized form, the benzoyl metabolites are reduced by NADPH in glutathione reductase-catalyzed reactions within the cytosols of infected red blood cells; (ii) in their reduced forms, these benzoyl metabolites can convert methemoglobin, the major nutrient of the parasite, to indigestible hemoglobin. Studies on a fluorinated suicide-substrate indicate as well that the glutathione reductase-catalyzed bioactivation of naphthoquinones is essential for the observed antimalarial activity. In conclusion, the antimalarial naphthoquinones are suggested to perturb the major redox equilibria of the targeted infected red blood cells, which might be removed by macrophages. This results in development arrest and death of the malaria parasite at the trophozoite stage

GRP78 as a marker of pre-eclampsia: an exploratory study

Although the exact mechanisms that lead to shallow invasion or defective trophoblastic differentiation in pre-eclampsia are still unknown, it is widely admitted that the etiology of pre-eclampsia is a defect in trophoblast invasion of the uterine spiral arteries. We have previously observed that the status of a chaperone protein, glucose regulated protein 78 (GRP78) is associated with the invasive properties of cytotrophoblastic cells; we therefore hypothesized that circulating GRP78 could serve as a diagnostic tool in pre-eclampsia. In a prospective case-control study, we quantified GRP78 autoantibodies, complexes of GRP78 with autoantibodies and GRP78 (C-term fragment, N-term fragment and full-length GRP78) by ELISA. Plasma from women diagnosed with pre-eclampsia (n = 16), from women during the first trimester of pregnancy who subsequently developed pre-eclampsia (n = 10) and from healthy pregnant women (controls, n = 58 at term, n = 26 at first trimester) were analysed and compared. We observed no significant difference between pre-eclamptic and healthy pregnant women for autoantibodies-GRP78 complexes or total GRP78 at both first trimester and at delivery. In contrast, the ratio of C-terminal GRP78 over full length GRP78 was significantly different in plasma of pre-eclamptic patients as compared with controls both during first trimester (P < 0.004) and at term (P < 0.0001). Our findings suggest that circulating C-terminal GRP78 reflect the invasive properties of cells, and could be used as a predictive marker for pre-eclampsia early in pregnanc

Malacoraja obscura, Brazilian Soft Skate

The Brazilian Soft Skate (Malacoraja obscura) is a small (to 68 cm total length) skate that has a very restricted range in the Southwest Atlantic Ocean from central Espírito Santo and northern Rio de Janeiro states in Brazil. It inhabits the continental slope at depths of 808-1,105 m. Although Extent of Occurrence cannot be calculated because the species is only known from two localities, it is suspected to be about 30,000 km2 (if the species is assumed to inhabit the steep slope between the two known localities). Area of Occupancy is estimated at 3,680 km2 (calculated based on including the known depth range of the species between the two known localities). This skate inhabits waters currently beyond the reach of fisheries, and there are no other known threats. Therefore, the population is suspected to be stable and the Brazilian Soft Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Capillarity in pressure infiltration: improvements in characterization of high-temperature systems

In the pressure infiltration of metal matrix composites, molten metal is injected under external pressure into a porous preform of the reinforcing material. Equilibrium capillary parameters characterizing wetting for this process are summarized in plots of metal saturation versus applied pressure, also known as drainage curves. Such curves can be measured in our laboratory during a single experiment with an infiltration apparatus designed to track the rate of metal penetration into porous preforms under conditions characteristic of metal matrix composite processing (temperatures in excess of 1000°C and pressures in the order of 10MPa). For such measurements to be valid, infiltration of the preform with molten metal must be mechanically quasi-static, i.e., the metal must flow at a rate sufficiently low for the metal pressure to be essentially uniform across the preform at all times. We examine this requirement quantitatively, using a finite-difference model that simulates the unsaturated unidirectional ingress of molten metal into a ceramic particle preform of finite width. We furthermore present improvements in the experimental apparatus developed in our laboratory to measure the entire drainage curve in a single experiment. We compare numerical results with new experimental data for the copper/alumina system to show (i) that pressurization rates sufficiently low for quasi-static infiltration can be produced with this apparatus, and (ii) that taking the relative permeability equal to the saturation yields better agreement with experiment than does the expression originally proposed by Brooks and Core

HDL and Glut1 inhibition reverse a hypermetabolic state in mouse models of myeloproliferative disorders

A high metabolic rate in myeloproliferative disorders is a common complication of neoplasms, but the underlying mechanisms are incompletely understood. Using three different mouse models of myeloproliferative disorders, including mice with defective cholesterol efflux pathways and two models based on expression of human leukemia disease alleles, we uncovered a mechanism by which proliferating and inflammatory myeloid cells take up and oxidize glucose during the feeding period, contributing to energy dissipation and subsequent loss of adipose mass. In vivo, lentiviral inhibition of Glut1 by shRNA prevented myeloproliferation and adipose tissue loss in mice with defective cholesterol efflux pathway in leukocytes. Thus, Glut1 was necessary to sustain proliferation and potentially divert glucose from fat storage. We also showed that overexpression of the human ApoA-I transgene to raise high-density lipoprotein (HDL) levels decreased Glut1 expression, dampened myeloproliferation, and prevented fat loss. These experiments suggest that inhibition of Glut-1 and HDL cholesterol-raising therapies could provide novel therapeutic approaches to treat the energy imbalance observed in myeloproliferative disorders

Properties of projectile-fragments in the 40^{40}Ar + 27^{27}Al reaction at 44 A MeV. Comparison with a multisequential decay model

GANIL-EXPResults on projectile fragment–fragment coincidences in the forward direction and for the reaction 40Ar + 27Al at 44 A MeV are presented and compared with the predictions of two different entrance channel models, a two-body and a three-body mechanism both followed by a binary multisequential decay including fission. This analysis shows that many features of the projectile decay products are well accounted for by the binary multisequential decay model. However the results depend critically upon the initial masses and excitation energies of the primary projectile fragments. In this respect, the three-body approach underestimates the excitation energy imparted to the primary fragments whereas the two-body scenario overestimates it. The present data put strong constraints on the initial excitation energy imparted to the primary fragments which appears to be intermediate between the predictions of the two models

New approach of fragment charge correlations in 129Xe+(nat)Sn central collisions

A previous analysis of the charge (Z) correlations in the $\Delta Z-$ plane for Xe+Sn central collisions at 32 MeV/u has shown an enhancement in the production of equally sized fragments (low $\Delta Z$) which was interpreted as an evidence for spinodal decomposition. However the signal is weak and rises the question of the estimation of the uncorrelated yield. After a critical analysis of its robustness, we propose in this paper a new technique to build the uncorrelated yield in the charge correlation function. The application of this method to Xe+Sn central collision data at 32, 39, 45 and 50 MeV/u does not show any particular enhancement of the correlation function in any $\Delta Z$ bin.Comment: 23 pages, 9 figures, revised version with an added figure and minor changes. To appear in Nuclear Physics

Bathyraja scaphiops, Cuphead Skate

The Cuphead Skate (Bathyraja scaphiops) is a medium-sized (to 117 cm total length) skate that occurs in the Southwest Atlantic from off Rio Grande do Sul, Brazil to Tierra del Fuego, Argentina and the Falkland Islands (Malvinas). It inhabits continental and insular shelves and slopes at depths of 30?925 m. It is targeted or captured as utilized bycatch in demersal trawl fisheries, including the southern Brazil otter trawl fishery, the Patagonian scallop and hake fisheries, and the Falkland Islands (Malvinas) targeted multi-species skate fishery. At the northern extent of its range in southern Brazil, it is captured in the otter trawl fishery which is intense; reductions in the population are suspected there but there are no data. In the Argentina-Uruguay Common Fishing Zone (AUCFZ), this species was captured frequently in commercial trawls between 1984 and 2009. On the shelf edge off Argentina between Buenos Aires and northern Santa Cruz, this species was present in 9% of research trawls in the area trawled by the Patagonian scallop fishery in 2010. In the Falkland Islands (Malvinas), this species made up an average of 3.5% of the catch in the multi-species skate fishery between 1993 and 2013, with no clear trend in catch-per-unit-effort over that time frame. Overall, although this species is subjected to substantial fishing pressure, it has remained common in catches and it may have refuge over rough substrates that are untrawlable. Although fisheries are likely leading to some reduction in population size, the level is not suspected to approach the thresholds for a threatened assessment. Therefore, the Cuphead Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Pompert, J.. No especifíca;Fil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

Sympterygia acuta, Bignose Fanskate

The Bignose Fanskate (Sympterygia acuta) is a small (to 62 cm total length) skate that occurs in the Southwest Atlantic from Rio de Janeiro, Brazil to Bahía Blanca, Buenos Aires, Argentina. It inhabits the continental shelf from inshore to 188 m depth. It is captured in intense largely unmanaged demersal trawl fisheries throughout its geographic range. It is one of the most commercially important species and the wings are sold mainly to Asian markets at high prices. In southern Brazil, research trawl catchper-unit-effort revealed a decline in biomass of 74.5% between 1974 and 2005, equivalent to a population reduction of >83% scaled over three generations (40.5 years). This species is a target of the longline fishery in Uruguay, but now it is uncommonly captured in research trawl surveys there. Further, in Argentina, total skate landings have peaked and are declining as a result of overfishing. Overall, due to intense and largely managed trawl fisheries that operate throughout its geographic and depth range, it is suspected that the Bignose Fanskate has undergone a population reduction of >80% over the past three generations (40.5 years), and it is assessed as Critically Endangered A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Barreto, R.. Centro Nacional Pesquisa E Conservação Da Biodiversidad; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Montealegre Quijano, S.. Universidade Federal de Sao Paulo; BrasilFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; Urugua