Reduced insulin action develops naturally during the peripartum to ensure maternal nutrient delivery to the fetus and neonate. However, increased insulin resistance can facilitate excessive lipolysis ...which in turn promotes metabolic disease in overweight dairy cattle. Increased fatty acid availability favors the accumulation of the sphingolipid ceramide and is implicated in the pathogenesis of insulin resistance, however, the relationship between sphingolipid metabolism and insulin resistance during the peripartum remains largely unknown. Our objectives were to characterize temporal responses in plasma and tissue sphingolipids in lean and overweight peripartal cows and to establish the relationships between sphingolipid supply and lipolysis, hepatic lipid deposition, and systemic insulin action. Twenty-one multiparous lean and overweight Holstein cows were enrolled in a longitudinal study spanning the transition from gestation to lactation (d -21 to 21, relative to parturition). Plasma, liver, and skeletal muscle samples were obtained, and sphingolipids were profiled using LC/MS/MS. Insulin sensitivity was assessed utilizing intravenous insulin and glucose challenges. Our results demonstrated the following: first, insulin resistance develops postpartum concurrently with increased lipolysis and hepatic lipid accumulation; second, ceramides and glycosylated ceramides accumulate during the transition from gestation to lactation and are further elevated in overweight cows; third, ceramide accrual is associated with lipolysis and liver lipid accumulation, and C16:0- and C24:0-ceramide are inversely associated with systemic insulin sensitivity postpartum; fourth, plasma sphingomyelin, a potential source of ceramides reaches a nadir at parturition and is closely associated with feed intake; fifth, select sphingomyelins are lower in the plasma of overweight cows during the peripartal period. Our results demonstrate that dynamic changes occur in peripartal sphingolipids that are influenced by adiposity, and are associated with the onset of peripartal insulin resistance. These observations are in agreement with a putative potential role for sphingolipids in facilitating the physiological adaptations of peripartum.
Biomorphic SiC is a biotemplated material fabricated by Si melt-infiltration of carbon preforms from wood pyrolysis. In this work, porous bioSiC ceramics from five different wood precursors, with ...porosities between 45 and 72% were studied for their feasibility in filtering applications.
Gas permeability and mechanical stability were investigated as a function of the microstructure of the starting wood precursor. Air-permeation performance at room temperature was measured for a range of flow rates, and the permeability constants were assessed by fitting of Forchheimer's equation to the experimental data. Darcian permeabilities were achieved in the range 10−11–10−12m2, while inertial terms were in the range 10−7–10−8m, showing a correlation with the average pore size and orientation of the larger channels. Regarding the mechanical stability, maximum compressive strength values were reached in the range of 3–115MPa.
These results improve our understanding of the ways in which the microstructure influences permeability and mechanical robustness, enabling the device requirements to be tailored by selecting the wood precursor. It was also shown that these materials are promising for hot-gas filtering applications.
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•Porous biomorphic SiC ceramics were tested for strength and permeability.•Porosity values ranging 45-73% resulted in permeability values of 10-11-10-12 m2.•Permeability, described by Forchheimer’s equation, depends mainly on the average pore size and pore alignment.•Experimental permeability constants are comparable to current commercial filters with adequate mechanical strength.•These materials with tailored permeability and mechanical properties are promising for hot-gas filtering applications.
Until recently, superhydrophobicity was considered as a hint to predict surface icephobicity, an association of concepts that is by no means universal and that has been proven to depend on different ...experimental factors and material properties, including the actual morphology and chemical state of surfaces. This work presents a systematic study of the wetting and freezing properties of aluminum Al6061, a common material widely used in aviation, after being subjected to nanosecond pulsed IR laser treatments to modify its surface roughness and morphology. All treated samples, independent of their surface finishing state, presented initially an unstable hydrophilic wetting behavior that naturally evolved with time to reach hydrophobicity or even superhydrophobicity. To stabilize the surface state and to bestow the samples with a permanent and stable hydrophobic character, laser-treated surfaces were covered with a thin layer of CF x prepared by plasma-enhanced chemical vapor deposition. A systematic comparison between freezing delay (FD) and wetting properties of water droplets onto these plasma-/polymer-modified laser-treated surfaces that, under conditions where a heterogeneous nucleation mechanism prevails, surface morphology rather than the actual value of the surface roughness parameter the key feature for long FD times. In particular, it is found that surface morphologies rendering a Cassie–Baxter wetting regime longer FDs than those characterized by a Wenzel-like wetting state. It is that laser treatment, with or without additional coverage with thin CF x coatings, affects wetting and ice formation behaviors and might be an efficient procedure to mitigate icing problems on metal surfaces.
•Confined Flames in biomass systems are studied for the abatement of particles.•Ceramic foams with different pore densities are tested in an in house test bench.•Microporous combustion was produced ...depending on foam positioning and porosity.•Best results show particles emission reduction above 60 per cent from free flame.•Particulate decreased up to one order of magnitude when reducing foam pore size.
This work explores the use of open-pore, inert ceramic foams with different pore sizes as particle abatement systems in small biomass combustion systems. Porous foams made of silicon carbide with pore sizes 10 to 60 pores-per-inch were installed in an in-house designed combustion unit operated with wood pellets. Their effects on the temperature distribution inside the chamber, particulate and gases emissions were studied using different airflow rates in the reaction-limited regime (low equivalence ratio) to minimise stoichiometric factors. The influence of pore size, foam position with respect to the flame and space velocity were assessed. The confinement of the flame with inert foams was found to substantially modify the temperature distribution in the combustion chamber, improve the air-fuel mixture, and favour the thermal decomposition of the pellet, leading to a reduction in particulate emissions when compared to free-flame combustion at the same experimental conditions. In general, the amount of particulate matter was found to decrease by up to one order of magnitude as the pore size of the foam was reduced, while the temperature gradient in the combustion chamber was increased. Nitrogen oxides and carbon dioxide emissions were essentially unchanged, irrespectively of the pore size of the foam. It is expected that these values will be improved with longer residence times, as happens in operations with reduced excess air ratios. These results suggest that it is possible to control pollutants derived from domestic heating within the most restrictive current regulations on particulate emissions by integrating flame confinement designs with better operating practices and efficient abatement systems.
Summary Kleine-Levin syndrome is a rare sleep disorder that mainly affects adolescents and is characterised by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, ...derealisation, and psychiatric and behavioural disturbances. Boys are more frequently affected than girls. Just over half of patients have hyperphagia, are hypersexual (mainly boys), or have depressed mood (mainly girls), and 30% become anxious, delusional, and have hallucinations. Although some symptoms are similar to those in patients with encephalopathy, imaging and laboratory findings are unremarkable. The first episode of hypersomnia is often triggered by an infection, with relapses occurring every 1–12 months for a median of 14 years; disease duration can be much longer with childhood or adult onset than in patients with adolescent onset. Between episodes, patients generally have normal sleep patterns, cognition, mood, and eating habits. During episodes, electroencephalography might show diffuse or local slow activity. Functional imaging studies have revealed hypoactivity in thalamic and hypothalamic regions, and in the frontal and temporal lobes. Stimulants and mood stabilisers can be beneficial in the treatment of severe cases.
Schistosoma mansoni is a parasitic helminth that infects millions of people mostly in tropical parts of the world. Different life cycle stages of S.mansoni, that infect or develop in the human host, ...promote distinct immune responses and are known for their ability to modulate host immune responses. However, the molecular mechanisms through which the parasites interact with, and modulate the host immune system remain incompletely understood. Despite the well-known ability of various lipids to modulate immune responses, a comprehensive analysis of the lipidome of the different life cycle stages has not been performed. Using three complementary MS-based platforms to detect and quantify around 350 lipid species, we here characterized the lipid profiles of S. mansoni cercariae, worms and eggs, as well as extracts and excretory/secretory (ES) products of different life cycle stages of S. mansoni. We identified life cycle stage specific signatures of lipid classes of which cercariae were found to have the most distinct profile. Moreover, we detected several immunolomodulatory oxylipids in the different life cycle stages. Specifically, prostaglandins were found to be most highly enriched in egg preparations, while resolvins were specifically detected in cercariae. Together, the generation of this detailed lipid database of the different life cycle stages of S. mansoni will not only be important for a better understanding of the biology of the parasite itself but also of host-parasite interactions and how that could result in immunomodulation.
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•Comprehensive Lipidomics study of Schistosoma mansoni and its life stages.•Description of a Schistosoma mansoni lipid database.•Identification of several important immunomodulatory lipids, leads for further research.
The potential benefits of ultra-low flow electrospray ionization (ESI) for the analysis of phosphopeptides in proteomics was investigated. First, the relative flow dependent ionization efficiency of ...nonphosphorylated vs multiplyphosphorylated peptides was characterized by infusion of a five synthetic peptide mix with zero to four phophorylation sites at flow rates ranging from 4.5 to 500 nL/min. Most importantly, similar to what was found earlier by Schmidt et al., it has been verified that at flow rates below 20 nL/min the relative peak intensities for the various peptides show a trend toward an equimolar response, which would be highly beneficial in phosphoproteomic analysis. As the technology to achieve liquid chromatography separation at flow rates below 20 nL/min is not readily available, a sheathless capillary electrophoresis–electrospray ionization-mass spectrometry (CE–ESI-MS) strategy based on the use of a neutrally coated separation capillary was used to develop an analytical strategy at flow rates as low as 6.6 nL/min. An in-line preconcentration technique, namely, transient isotachophoresis (t-ITP), to achieve efficient separation while using larger volume injections (37% of capillary thus 250 nL) was incorporated to achieve even greater sample concentration sensitivities. The developed t-ITP-ESI-MS strategy was then used in a direct comparison with nano-LC–MS for the detection of phosphopeptides. The comparison showed significantly improved phosphopeptide sensitivity in equal sample load and equal sample concentration conditions for CE–MS while providing complementary data to LC–MS, demonstrating the potential of ultra-low flow ESI for the analysis of phosphopeptides in liquid based separation techniques.
Few behavioral tests allow measuring several characteristics and most require training, complex analyses, and/or are time-consuming. We present an apparatus based on rat exploratory behavior. ...Composed of three different environments, it allows the assessment of more than one behavioral characteristic in a short 3-min session. Factorial analyses have defined three behavioral dimensions, which we named Exploration, Impulsivity, and Self-protection. Behaviors composing the Exploration factor were increased by chlordiazepoxide and apomorphine and decreased by pentylenetetrazole. Behaviors composing the Impulsivity factor were increased by chlordiazepoxide, apomorphine, and both acute and chronic imipramine treatments. Behaviors composing the Self-protection factor were decreased by apomorphine. We submitted Wistar rats to the open-field test, the elevated-plus maze, and to the apparatus we are proposing. Measures related to exploratory behavior in all three tests were correlated. Measures composing the factors Impulsivity and Self-protection did not correlate with any measures from the two standard tests. Also, compared with existing impulsivity tests, the one we proposed did not require previous learning, training, or sophisticated analysis. Exploration measures from our test are as easy to obtain as the ones from other standard tests. Thus, we have proposed an apparatus that measured three different behavioral characteristics, was simple and fast, did not require subjects to be submitted to previous learning or training, was sensitive to drug treatments, and did not require sophisticated data analyses. Key words: Anxiety; Exploratory behavior; Impulsivity; Rat; Fear; Self-protection
This article investigates the history of proposals to use vegetable oils as fuel in Brazil beginning in the 1920s up to the current National Program for Biodiesel Production and Use – PNPB. The ...characteristics of vegetable oils markets and of the oil products market, as well as the incentive mechanisms formulated for biodiesel implementation, are analyzed. Although the research focuses on the Brazilian experience, initiatives of biodiesel insertion, or those already implemented in countries with significant oilseeds production are also studied. The results allow concluding that attempts to make biodiesel production viable confront several barriers. Comparative analysis revealed that vegetable oil world prices tend to be higher than the equivalent fossil oils. In Brazil, the initiative in the 1970s lacked political alliances to overcome the difficulties imposed by market conditions such as those that benefited the National Alcohol Program –Proalcool. In the resumption of the 2000s with PNPB, despite intense articulation and institutional incentives, arising from the limited scale of production of the feedstock from incentived family farming and from the nature of markets of vegetable oils, as food or fuel, and of fossil oils, especially regarding the respective regulating prices. The incentives provided by the PNPB seem insufficient for vegetable oils to prefer the energy market instead of benefiting from higher surplus in alternative food markets.
•The usage of the proposed power electronics configuration instead of a multilevel converter is justified.•Details of the system and what type of nonlinear loads employed while doing simulation are ...presented.•Input-affine nonlinear systems are explained in detail.•References from the Electric Power System Research journal are included.•The conclusion Section has been improved with strong results and discussion.
Modern electrical power grids are susceptible to several problems in terms of power quality due to the integration of renewable energy sources, the connection of nonlinear loads, and power electronics-based devices. In this sense, this work proposes a novel nonlinear control scheme that allows, through the use of a power electronic converter, to provide ancillary services to the electrical power grid, intending to achieve three different control objectives: voltage regulation, harmonic distortion compensation, and the power factor correction at a power system node, depending on the end-user requirements, and by doing so enhance the power quality. The proposed control scheme uses nested control loops based on super-twisting sliding modes, nonlinear optimal tracking control, and a fast-convergent harmonic estimator with a decentralized structure. Simulation results validate the effectiveness of our proposed scheme.
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