352 research outputs found

    Identification of Behavioral and Metabolic Factors Predicting Adiposity Sensitivity to Both High Fat and High Carbohydrate Diets in Rats

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    Individuals exhibit a great variation in their body weight (BW) gain response to a high fat diet. Identification of predictive factors would enable better directed intervention toward susceptible individuals to treat obesity, and uncover potential mechanisms for treatment targeting. We set out to identify predictive behavioral and metabolic factors in an outbred rat model. 12 rats were analyzed in metabolic cages for a period of 5 days during both high carbohydrate diet (HCD), and transition to a high fat diet (HFD). After a recovery period, rats were given a HFD for 6 days to identify those resistant or sensitive to it according to BW gain. Rats were dissected at the end of the study to analyze body composition. This showed that small differences in final BW hid large variations in adiposity, allowing separation of rats into a second classification (final adiposity). Since these rats had been fed a HCD during most of their life, under which most of the adiposity presumably evolved, we considered this carbohydrate-sensitivity or -resistance. Meal size and meal number were found to be good predictors of sensitivity to a HFD, intensity of motor activity and ingestion speed good predictors of sensitivity to a HCD. Rats that were sensitive to the HCD could be resistant to the HFD and vice versa. This points to four types of individuals (carbohydrate/fat resistant/sensitive) though our sample size inhibited deeper investigation of this. This contributes to the idea that to be “obesity prone” does not necessarily need a HFD, it can also happen under a HCD, and be a hidden adiposity change with stable BW

    Multi-physical analysis of the electrochemical behaviour of OFHC copper surfaces obtained by orthogonal cutting

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    As mechanical, physical, and microstructural properties of metals can be significantly affected by the machining process, electrochemical properties and corrosion resistance are consequently altered. Manufacturers should control the impact of cutting conditions on surface integrity, as it will affect the component’s functional performance and life. This study addresses the case of orthogonal cutting of oxygen-free high conductivity (OFHC) copper. A set of experiments was performed and a statistical analysis was conducted to reveal the relationship between the cutting conditions and the surface integrity in terms of residual stresses, microstructure, plastic deformation and hardness, and the impact of those parameters on the electrochemical behavior. The physical origins of the observed phenomena are explained. The results show that the surface performance can be controlled by selecting the appropriate cutting conditions (e.g., reducing the tensile residual stress and roughness by more than 75%), such that the electrochemical behavior can be enhanced

    Study of vibrational kinetics of CO2 and CO in CO2-O2 plasmas under non-equilibrium conditions

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    This work explores the effect of O2 addition on CO2 dissociation and on the vibrational kinetics of CO2 and CO under various non-equilibrium plasma conditions. A self-consistent model, previously validated for pure CO2 discharges, is further extended by adding the vibrational kinetics of CO, including electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) and vibration-to-vibration energy exchange (V-V) processes. The vibrational kinetics considered include levels up to v = 10 for CO and up to v1=2 and v2=v3=5, respectively for the symmetric stretch, bending and asymmetric stretch modes of CO2, and accounts for e-V, V-T in collisions between CO, CO2 and O2 molecules and O atoms and V-V processes involving all possible transfers involving CO2 and CO molecules. The kinetic scheme is validated by comparing the model predictions with recent experimental data measured in a DC glow discharge, operating at pressures in the range 0.4 - 5 Torr (53.33 - 666.66 Pa). The experimental results show a lower vibrational temperature of the different modes of CO2 and a decreased dissociation fraction of CO2 when O2 is added to the plasma but an increase of the vibrational temperature of CO. On the one hand, the simulations suggest that the former effect is the result of the stronger V-T energy-transfer collisions with O atoms which leads to an increase of the relaxation of the CO2 vibrational modes; On the other hand, the back reactions with O2 contribute to the lower CO2 dissociation fraction with increased O2 content in the mixture.Comment: 34 pages 15 figure

    Spontaneous HIV expression during suppressive ART is associated with the magnitude and function of HIV-specific CD4+ and CD8+ T cells.

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    Spontaneous transcription and translation of HIV can persist during suppressive antiretroviral therapy (ART). The quantity, phenotype, and biological relevance of this spontaneously "active" reservoir remain unclear. Using multiplexed single-cell RNAflow-fluorescence in situ hybridization (FISH), we detect active HIV transcription in 14/18 people with HIV on suppressive ART, with a median of 28/million CD4 <sup>+</sup> T cells. While these cells predominantly exhibit abortive transcription, p24-expressing cells are evident in 39% of participants. Phenotypically diverse, active reservoirs are enriched in central memory T cells and CCR6- and activation-marker-expressing cells. The magnitude of the active reservoir positively correlates with total HIV-specific CD4 <sup>+</sup> and CD8 <sup>+</sup> T cell responses and with multiple HIV-specific T cell clusters identified by unsupervised analysis. These associations are particularly strong with p24-expressing active reservoir cells. Single-cell vDNA sequencing shows that active reservoirs are largely dominated by defective proviruses. Our data suggest that these reservoirs maintain HIV-specific CD4 <sup>+</sup> and CD8 <sup>+</sup> T responses during suppressive ART

    Climate fluctuations and the spring invasion of the North Sea by Calanus finmarchicus

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    The population of Calanus finmarchicus in the North Sea is replenished each spring by invasion from an overwintering stock located beyond the shelf edge. A combincation of field observations, statistical analysis of Continuous Plankton Recorder (CPR) data, and particle tracking model simulations, was used to investigate the processes involved in the cross-shelf invasion. The results showed that the main source of overwintering animals entering the North Sea in the spring is at depths of greater than 600m in the Faroe Shetland Channel, where concentrations of up to 620m -3 are found in association with the overflow of Norwegian Sea Deep Water (NSDW) across the Iceland Scotland Ridge. The input of this water mass to the Faroe Shetland Channel, and hence the supply of overwintering C. finmarchicus, has declined since the late 1960s due to changes in convective processes in the Greenland Sea. Beginning in February, animals start to emerge from the overwintering state and migrate to the surface waters, where their transport into the North Sea is mainly determined by the incidence of north-westerly winds that have declined since the 1960s. Together, these two factors explain a high proportion of the 30-year trends in spring abundance in the North Sea as measured by the CPR survey. Both the regional winds and the NSDW overflow are connected to the North Atlantic Oscillation Index (NAO), which is an atmospheric climate index, but with different time scales of response. Thus, interannual fluctuations in the NAO can cause immediate changes in the incidence of north-westerly winds without leading to corresponding changes in C. finmarchicus abundance in the North Sea, because the NSDW overflow responds over longer (decadal) time scales

    Dietary soy and meat proteins induce distinct physiological and gene expression changes in rats

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    This study reports on a comprehensive comparison of the effects of soy and meat proteins given at the recommended level on physiological markers of metabolic syndrome and the hepatic transcriptome. Male rats were fed semi-synthetic diets for 1 wk that differed only regarding protein source, with casein serving as reference. Body weight gain and adipose tissue mass were significantly reduced by soy but not meat proteins. The insulin resistance index was improved by soy, and to a lesser extent by meat proteins. Liver triacylglycerol contents were reduced by both protein sources, which coincided with increased plasma triacylglycerol concentrations. Both soy and meat proteins changed plasma amino acid patterns. The expression of 1571 and 1369 genes were altered by soy and meat proteins respectively. Functional classification revealed that lipid, energy and amino acid metabolic pathways, as well as insulin signaling pathways were regulated differently by soy and meat proteins. Several transcriptional regulators, including NFE2L2, ATF4, Srebf1 and Rictor were identified as potential key upstream regulators. These results suggest that soy and meat proteins induce distinct physiological and gene expression responses in rats and provide novel evidence and suggestions for the health effects of different protein sources in human diets

    Implementing YewPar: a framework for parallel tree search

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    Combinatorial search is central to many applications yet hard to parallelise. We argue for improving the reuse of parallel searches, and present the design and implementation of a new parallel search framework. YewPar generalises search by abstracting search tree generation, and by providing algorithmic skeletons that support three search types, together with a set of search coordination strategies. The evaluation shows that the cost of YewPar generality is low (6.1%); global knowledge is inexpensively shared between workers; irregular tasks are effectively distributed; and YewPar delivers good runtimes, speedups and efficiency with up to 255 workers on 17 localitie

    Mesoscale productivity fronts and local fishing opportunities in the European Seas

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    This study evaluates the relationship between both commercial and scientific spatial fisheries data and a new satellite-based estimate of potential fish production (Ocean Productivity available to Fish, OPFish) in the European Seas. To construct OPFish, we used productivity frontal features derived from chlorophyll-a horizontal gradients, which characterize 10%–20% of the global phytoplankton production that effectively fuels higher trophic levels. OPFish is relatively consistent with the spatial distribution of both pelagic and demersal fish landings and catches per unit of effort (LPUEs and CPUEs, respectively). An index of harvest relative to ocean productivity (HP index) is calculated by dividing these LPUEs or CPUEs with OPFish. The HP index reflects the intensity of fishing by gear type with regard to local fish production. Low HP levels indicate lower LPUEs or CPUEs than expected from oceanic production, suggesting over-exploitation, while high HP levels imply more sustainable fishing. HP allows comparing the production-dependent suitability of local fishing intensities. Our results from bottom trawl data highlight that over-exploitation of demersal species from the shelves is twice as high in the Mediterranean Sea than in the North-East Atlantic. The estimate of HP index by dominant pelagic and demersal gears suggests that midwater and bottom otter trawls are associated with the lowest and highest overfishing, respectively. The contrasts of fishing intensity at local scales captured by the HP index suggest that accounting for the local potential fish production can promote fisheries sustainability in the context of ecosystem-based fisheries management as required by international marine policies

    Mesoscale productivity fronts and local fishing opportunities in the European Seas. Fish and Fisheries

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    This study evaluates the relationship between both commercial and scientific spatial fisheries data and a new satellite-based estimate of potential fish production (Ocean Productivity available to Fish, OPFish) in the European Seas. To construct OPFish, we used productivity frontal features derived from chlorophyll-a horizontal gradients, which characterize 10%–20% of the global phytoplankton production that effectively fuels higher trophic levels. OPFish is relatively consistent with the spatial distribution of both pelagic and demersal fish landings and catches per unit of effort (LPUEs and CPUEs, respectively). An index of harvest relative to ocean productivity (HP index) is calculated by dividing these LPUEs or CPUEs with OPFish. The HP index reflects the intensity of fishing by gear type with regard to local fish production. Low HP levels indicate lower LPUEs or CPUEs than expected from oceanic production, suggesting over-exploitation, while high HP levels imply more sustainable fishing. HP allows comparing the production-dependent suitability of local fishing intensities. Our results from bottom trawl data highlight that over-exploitation of demersal species from the shelves is twice as high in the Mediterranean Sea than in the North-East Atlantic. The estimate of HP index by dominant pelagic and demersal gears suggests that midwater and bottom otter trawls are associated with the lowest and highest overfishing, respectively. The contrasts of fishing intensity at local scales captured by the HP index suggest that accounting for the local potential fish production can promote fisheries sustainability in the context of ecosystem-based fisheries management as required by international marine policies
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