This letter presents a combined measurement of the energy spectra of atmospheric νe and νμ in the energy range between ∼100 GeV and ∼50 TeV with the ANTARES neutrino telescope. The analysis uses 3012 ...days of detector livetime in the period 2007–2017, and selects 1016 neutrinos interacting in (or close to) the instrumented volume of the detector, yielding shower-like events (mainly from νe+ν‾e charged current plus all neutrino neutral current interactions) and starting track events (mainly from νμ+ν‾μ charged current interactions). The contamination by atmospheric muons in the final sample is suppressed at the level of a few per mill by different steps in the selection analysis, including a Boosted Decision Tree classifier. The distribution of reconstructed events is unfolded in terms of electron and muon neutrino fluxes. The derived energy spectra are compared with previous measurements that, above 100 GeV, are limited to experiments in polar ice and, for νμ, to Super-Kamiokande.
The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP) and carbon export ...remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ) and the northern reaches of the Polar Frontal Zone (PFZ), we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense) study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m), dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. The strong correlation between NCP and dissolved Fe may be difficult to interpret because of the correlation of dissolved Fe to MLD and because the concentration of iron may not be a good indicator of its availability. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.
Molding composites constituted of fiber reinforcements, resin and fillers is of prime interest for many transportation applications. Dealing with the flow of particle-filled resin in a fibrous ...network raises the issue of particle retention and viscosity increase. The present study aims at simulating such molding through an efficient coupling between a filtration model, that has been previously described, and a flow model (Darcy’s law). First, filling experiments are realized so as to separate cases: cake filtration, retention and no retention for two types of single-scale porous materials (polyester felt and glass fiber mat) injected with a resin filled with micro-beads. Then results of filler content, viscosity, permeability, pressure, retention profiles are simulated from the coupling between filtration and flow. Experimental data of filler profiles in the final parts, resin flow front evolution and injection times are compared with predictions obtained from the simulation.
Programme Océan Multidisciplinaire Méso Echelle (POMME) seasonal surveys in the northeast Atlantic (39°N–44.5°N; 16.5°W–20.3°W) in 2001 are used to investigate the subduction of nutrients in the ...subsurface mode waters. Isopycnal subsurface distributions are used to estimate inorganic nutrients at the time of late winter restratification. These nutrient concentrations were close to winter near‐surface concentrations, indicating a moderate consumption of nitrate (0.2–0.3 μM kg−1) and dissolved inorganic carbon (2–3 μM kg−1) in the surface layer before the effective subduction. Spring survey nutrient concentrations on isopycnal surfaces are lower north of 41.7°N indicating younger waters than further south. The seasonal increase of subsurface nutrients from spring to late summer diminishes from the shallower isopycnals to the deeper ones of the mode waters. It is also larger north of 41.7°N than south of it with values as large as 2 μM kg−1 for nitrate and 10 μM kg−1 for inorganic carbon. This evolution is mostly attributed to remineralization processes, both from falling particles (at least 15%) and from preformed dissolved organic matter (at most 30%). Ratios of nutrient changes to oxygen changes are often larger than Redfield ratios for nitrate (N:apparent oxygen utilization (AOU) at least 1:7) and phosphate (P:AOU at least 1:150) consistent with favored remineralization of P and N over C, both for dissolved and particulate organic pools.
Two main isoforms of the Translocator Protein (TSPO) have been identified. TSPO1 is ubiquitous and is mainly present at the outer mitochondrial membrane of most eukaryotic cells, whereas, TSPO2 is ...specific to the erythroid lineage, located at the plasma membrane, the nucleus, and the endoplasmic reticulum. The design of specific tools is necessary to determine the molecular associations and functions of TSPO, which remain controversial nowadays. We recently demonstrated that TSPO2 is involved in a supramolecular complex of the erythrocyte membrane, where micromolar doses of the classical TSPO ligands induce ATP release and zinc protoporphyrin (ZnPPIX) transport. In this work, three newly-designed ligands (NCS1016, NCS1018, and NCS1026) were assessed for their ability to modulate the functions of various erythrocyte's and compare them to the TSPO classical ligands. The three new ligands were effective in reducing intraerythrocytic
growth, without compromising erythrocyte survival. While NCS1016 and NCS1018 were the most effective ligands in delaying sorbitol-induced hemolysis, NCS1016 induced the highest uptake of ZnPPIX and NCS1026 was the only ligand inhibiting the cholesterol uptake. Differential effects of ligands are probably due, not only, to ligand features, but also to the dynamic interaction of TSPO with various partners at the cell membrane. Further studies are necessary to fully understand the mechanisms of the TSPO's complex activation.
After invading red blood cells (RBCs), Plasmodium falciparum (Pf) can export its own proteins to the host membrane and activate endogenous channels that are present in the membrane of RBCs. This ...transport pathway involves the Voltage Dependent Anion Channel (VDAC). Moreover, ligands of the VDAC partner TranSlocator PrOtein (TSPO) were demonstrated to inhibit the growth of the parasite. We studied the expression of TSPO and VDAC isoforms in late erythroid precursors, examined the presence of these proteins in membranes of non-infected and infected human RBCs, and evaluated the efficiency of TSPO ligands in inhibiting plasmodium growth, transporting the haem analogue Zn-protoporphyrin-IX (ZnPPIX) and enhancing the accumulation of reactive oxygen species (ROS). TSPO and VDAC isoforms are differentially expressed on erythroid cells in late differentiation states. TSPO2 and VDAC are present in the membranes of mature RBCs in a unique protein complex that changes the affinity of TSPO ligands after Pf infection. TSPO ligands dose-dependently inhibited parasite growth, and this inhibition was correlated to ZnPPIX uptake and ROS accumulation in the infected RBCs. Our results demonstrate that TSPO ligands can induce Pf death by increasing the uptake of porphyrins through a TSPO2-VDAC complex, which leads to an accumulation of ROS.
Microstructure measurements were performed along the
OUTPACE longitudinal transect in the tropical Pacific
(Moutin and Bonnet, 2015). Small-scale dynamics and turbulence in the first
800 m surface ...layer were characterized based on hydrographic and current
measurements at fine vertical scale and turbulence measurements at
centimeter scale using a vertical microstructure profiler. The possible
impact of turbulence on biogeochemical budgets in the surface layer was also
addressed in this region of increasing oligotrophy to the east. The
dissipation rate of turbulent kinetic energy, ϵ, showed an
interesting contrast along the longitudinal transect with stronger
turbulence in the west, i.e., the Melanesian Archipelago, compared to the
east, within the South Pacific Subtropical Gyre, with a variation of
ϵ by a factor of 3 within 100–500 m. The layer with enhanced
turbulence decreased in vertical extent travelling eastward. This spatial
pattern was correlated with the energy level of the internal wave field,
higher in the west compared to the east. The difference in wave energy mostly
resulted from enhanced wind power input into inertial motions in the west.
Moreover, three long-duration stations were sampled along the cruise
transect, each over three inertial periods. The analysis from the western
long-duration station gave evidence of an energetic baroclinic near-inertial
wave that was responsible for the enhanced ϵ, observed within a
50–250 m layer, with a value of 8×10-9 W kg−1, about 8
times larger than at the eastern long-duration stations. Averaged nitrate
turbulent diffusive fluxes in a 100 m layer below the top of the
nitracline were about twice larger west of 170∘ W due to the
higher vertical diffusion coefficient. In the photic layer, the
depth-averaged nitrate turbulent diffusive flux strongly decreased
eastward, with an averaged value of 11 µmolm-2d-1 west of
170∘ W compared with the 3 µmolm-2d-1 averaged
value east of 170∘ W. Contrastingly, phosphate turbulent diffusive
fluxes were significantly larger in the photic layer. This input may have an
important role in sustaining the development of N2-fixing organisms
that were shown to be the main primary contributors to the biological pump in
the area. The time–space intermittency of mixing events, intrinsic to
turbulence, was underlined, but its consequences for micro-organisms would
deserve a dedicated study.
A carbonate chemistry balance module was implemented into a biogeochemical model of the planktonic food web. The model, named Eco3M-CarbOx, includes
22 state variables that are dispatched into ...5 compartments: phytoplankton, heterotrophic bacteria, detrital particulate organic matter, labile
dissolved organic, and inorganic matter. This model is applied to and evaluated in the Bay of Marseille (BoM, France), which is a coastal zone impacted
by the urbanized and industrialized Aix–Marseille Metropolis, and subject to significant increases in anthropogenic emissions of CO2. The model was evaluated over the year 2017, for which in situ data of the carbonate system are available in the study site. The biogeochemical state
variables of the model only change with time, to represent the time evolution of a sea surface water cell in response to the implemented realistic
forcing conditions. The model correctly simulates the value ranges and seasonal dynamics of most of the variables of the carbonate system except for the
total alkalinity. Several numerical experiments were conducted to test the response of carbonate system to (i) a seawater temperature increase,
(ii) wind events, (iii) Rhône River plume intrusions, and (iv) different levels of atmospheric CO2 contents. This set of numerical experiments
shows that the Eco3M-CarbOx model provides expected responses in the alteration of the marine carbonate balance regarding each of the considered
perturbation. When the seawater temperature changes quickly, the behavior of the BoM waters alters within a few days from a source of CO2
to the atmosphere to a sink into the ocean. Moreover, the higher the wind speed is, the higher the air–sea CO2 gas exchange fluxes
are. The river intrusions with nitrate supplies lead to a decrease in the pCO2 value, favoring the conditions of a sink for atmospheric
CO2 into the BoM. A scenario of high atmospheric concentrations of CO2 also favors the conditions of a sink for atmospheric
CO2 into the waters of the BoM. Thus the model results suggest that external forcings have an important impact on the carbonate
equilibrium in this coastal area.
The most active deep convection area in the western Mediterranean Sea is located in the Gulf of Lions. Recent studies in this area provides some insights on the complexity of the physical dynamics of ...convective regions, but very little is known about their impacts on the biogeochemical properties. The CASCADE (CAscading, Surge, Convection, Advection and Downwelling Events) cruise, planed in winter 2011, give us the opportunity to compare vertical profiles of properties sampled either during stratified conditions or after/during a convection event. In the present study, we focus on the distributions of the carbonate system properties (mainly total alkalinity, A^sub T^; and total dissolved inorganic carbon, C^sub T^) because, in the context of the climate change, deep convection areas are suspected to significantly increase the sequestration of anthropogenic CO2 (C^sub ANT^). Given its limited size, the impact of the Mediterranean Sea on the global carbon budget is probably minor but this marginal sea can be used as a laboratory to better understand carbon sequestration and its transfer to the basin interior by deep convection processes. Distributions of A^sub T^ and C^sub T^, both measured from bottle samples, and that of C^sub ANT^ (estimated with the TrOCA approach) are first analyzed in the light of other key properties (salinity, temperature, and dissolved oxygen). An objective interpolation procedure is then applied to estimate C^sub T^ and A^sub T^ from CTD measured properties. With this procedure, the vertical resolution goes from a maximum of 32 samples per station to one property estimate every meter (more detailed distributions are obtained). Results provide arguments to conclude that CANT is rapidly transferred to the deepest layer due to deep convection events. During deep convection events, the increase of C^sub ANT^ in the water column is positively correlated to that of potential density and oxygen content. The challenge of quantifying the amount of sequestered carbon is however not resolved due to the complexity and the highly dynamical nature of the convective regions. Deep convection in the Gulf of Lions, in parallel with cascading along the continental slope, could thus potentially explain the very high levels of both C^sub ANT^ and acidification estimated in the deep layers of the western Mediterranean Sea.
Chronological aging of yeast cells is commonly used as a model for aging of human post-mitotic cells. The yeast Saccharomyces cerevisiae grown on glucose in the presence of ammonium sulphate is ...mainly used in yeast aging research. We have analyzed chronological aging of the yeast Hansenula polymorpha grown at conditions that require primary peroxisome metabolism for growth.
The chronological lifespan of H. polymorpha is strongly enhanced when cells are grown on methanol or ethanol, metabolized by peroxisome enzymes, relative to growth on glucose that does not require peroxisomes. The short lifespan of H. polymorpha on glucose is mainly due to medium acidification, whereas most likely ROS do not play an important role. Growth of cells on methanol/methylamine instead of methanol/ammonium sulphate resulted in further lifespan enhancement. This was unrelated to medium acidification. We show that oxidation of methylamine by peroxisomal amine oxidase at carbon starvation conditions is responsible for lifespan extension. The methylamine oxidation product formaldehyde is further oxidized resulting in NADH generation, which contributes to increased ATP generation and reduction of ROS levels in the stationary phase.
We conclude that primary peroxisome metabolism enhanced chronological lifespan of H. polymorpha. Moreover, the possibility to generate NADH at carbon starvation conditions by an organic nitrogen source supports further extension of the lifespan of the cell. Consequently, the interpretation of CLS analyses in yeast should include possible effects on the energy status of the cell.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
