Maternal Choline Intake Programs Hypothalamic Energy Regulation and Later‐Life Phenotype of Male Wistar Rat Offspring

Scope: High‐folic‐acid diets during pregnancy result in obesity in the offspring, associated with altered DNA‐methylation of hypothalamic food intake neurons. Like folic acid, the methyl‐donor choline modulates foetal brain development, but its long‐term programing effects on energy regulation remain undefined. This study aims to describe the effect of choline intake during pregnancy on offspring phenotype and hypothalamic energy‐regulatory mechanisms. Methods and results: Wistar rat dams are fed an AIN‐93G diet with recommended choline (RC, 1 g kg^?1 diet), low choline (LC, 0.5‐fold), or high choline (HC, 2.5‐fold) during pregnancy. Male pups are terminated at birth and 17 weeks post‐weaning. Brain 1‐carbon metabolites, body weight, food intake, energy expenditure, plasma hormones, and protein expression of hypothalamic neuropeptides are measured. HC pups have higher expression of the orexigenic neuropeptide‐Y neurons at birth, consistent with higher cumulative food intake and body weight gain post‐weaning compared to RC and LC offspring. LC pups have lower leptin receptor expression at birth and lower energy expenditure and activity during adulthood. Conclusion: Choline content of diets that are consumed by rats during pregnancy affects the later‐life phenotype of offspring, associated with altered in utero programing of hypothalamic food intake regulation.     

Involvement of Reactive Oxygen Species in ABA-Induced Increase in Hydraulic Conductivity and Aquaporin Abundance

The role of reactive oxygen species (ROS) in ABA-induced increase in hydraulic conductivity was hypothesized to be dependent on an increase in aquaporin water channel (AQP) abundance. Single ABA application or its combination with ROS manipulators (ROS scavenger ascorbic acid and NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI)) were studied on detached roots of barley plants. We measured the osmotically driven flow rate of xylem sap and calculated root hydraulic conductivity. In parallel, immunolocalization of ABA and HvPIP2;2 AQPs was performed with corresponding specific antibodies. ABA treatment increased the flow rate of xylem, root hydraulic conductivity and immunostaining for ABA and HvPIP2;2, while the addition of antioxidants prevented the effects of this hormone. The obtained results confirmed the involvement of ROS in ABA effect on hydraulic conductivity, in particular, the importance of H₂O₂ production by ABA-treated plants for the effect of this hormone on AQP abundance.     

Cost- and performance-aware resource selection for parallel software on heterogeneous cloud

Cloud providers offer flexible infrastructures and on-demand services, including the capability to deploy low cost virtual resources of many different types. However, the diversity of cloud resources followed by the important trade-off between cost and performance makes the resource selection a challenging task for users in the case of parallel communication-intensive software. The paper presents cost- and performance-aware resource selection for parallel discrete element method (DEM) software as a service (SaaS) on heterogeneous OpenStack cloud. The developed resource selection uses preliminary application-specific benchmarks of size smaller than targeted problems and the performance prediction based on speedup of parallel computations to obtain Pareto optimal solutions and to select the best configuration of containers from user's perspective. Hybrid parallelization of DEM software is developed by using OpenCL for shared-memory multi-core architectures and MPI for internode communications on distributed-memory computer clusters. Round up and proportional pricing schemes are examined and compared from a user's perspective. Lower cost of computations obtained by using the proportional pricing scheme is always preferable for users. However, the difference approaches 1.0% of the cost calculated by using proportional pricing scheme, when long lasting computations are performed. The prediction tends to underestimate the execution time of DEM SaaS, but its accuracy is sufficient to obtain the same Pareto optimal solutions by using measured and predicted execution times. Pareto front and linear scalarization propose to select configurations of containers capable of exploiting higher memory bandwidth, which is specific to memory bandwidth bound DEM computations.     

Special nanostructures in Al-Mg alloys subjected to high pressure torsion

Deformation twins and stacking faults were observed in nanostructure Al-Mg alloys subjected to high pressure torsion. These observations are surprising because deformation twinnings have never been observed in their coarse-grained counterparts under normal conditions. Experimental evidences are introduced on non-equilibrium grain boundaries, deformation twinnings and partial dislocation emissions from grain boundaries. Some of these features can be explained by the results reported from molecular-dynamics simulations of pure FCC metals. Special emphasis is laid on the recent observations of high density hexagonal and rhombic shaped nanostructures with an average size of 3 nm in the Al-Mg alloys processed by high pressure torsion. A possible formation process of these nanostructures is proposed based on molecular-dynamics simulations.     

Tensile properties of glass microballoon‐epoxy resin syntactic foams

The effect of hollow glass particle (microballoon) volume fraction in the range of 0.3–0.6 on the tensile properties and fracture mode of syntactic foams is characterized in the present research. Sixteen types of syntactic foams have been fabricated and tested. Four types of glass microballoons, having 220, 320, 380, and 460 kg/m³ density, are used with epoxy resin matrix for making the syntactic foam samples. These foams contain 30, 40, 50 and 60% microballoons by volume. All types of microballoons have the same size but different wall thickness, which reflects as a difference in their density. It is observed that the tensile strength increases with a decrease in the volume fraction of microballoons. All types of syntactic foams showed 60–80% decrease in the tensile strength compared with that of the neat resin. The foams containing low strength microballoons showed lower tensile modulus compared with that of the neat resin, but the presence of high strength microballoons led to an increase in the tensile modulus of the composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1254–1261, 2006     

Tribological study on the surface modification of metal-on-polymer bioimplants

The tribological performance of artificial joints is regarded as the main factor of the lifespan of implanted prostheses. The relationship between surface roughness and coefficient of friction (COF) under dry and lubricated conditions is studied. Results show that under dry test, friction coefficient is not reduced all the time with a decrease in surface roughness. On the contrary, a threshold of roughness value is observed, and frictional force increases again below this value. This critical value lies between 40 and 100 nm in S_a (roughness). This phenomenon is due to the transfer of friction mechanisms from abrasion to adhesion. Under wet test, COF always decreases with reduction in surface roughness. This result is mainly attributed to the existence of a thin layer of lubricant film that prevents the intimate contact of two articulating surfaces, thus greatly alleviating adhesion friction. Furthermore, surface texturing technology is successful in improving the corresponding tribological performance by decreasing friction force and mitigating surface deterioration. The even-distribution mode of texturing patterns is most suitable for artificial joints. By obtaining the optimal surface roughness and applying texturing technology, the tribological performance of polymer-based bioimplants can be greatly enhanced.     

Nanoparticle‐Based Fluoroionophore for Analysis of Potassium Ion Dynamics in 3D Tissue Models and In Vivo

The imaging of real‐time fluxes of K⁺ ions in live cell with high dynamic range (5–150 × 10^?3m ) is of paramount importance for neuroscience and physiology of the gastrointestinal tract, kidney, and other tissues. In particular, the research on high‐performance deep‐red fluorescent nanoparticle‐based biosensors is highly anticipated. It is found that boron‐dipyrromethene (BODIPY)‐based K⁺‐sensitive fluoroionophore FI3 encapsulated in cationic polymer RL100 nanoparticles displays unusually strong efficiency in staining of broad spectrum of cell models, such as primary neurons and intestinal organoids. Using comparison of brightness, photostability, and fluorescence lifetime imaging microscopy, it is confirmed that FI3 nanoparticles display distinctively superior intracellular staining compared to the free dye. FI3 nanoparticles in real‐time live cell imaging are evaluated and it is found highly useful for monitoring intra‐ and extracellular K⁺ dynamics in cultured neurons. Proof‐of‐concept in vivo brain imaging confirms applicability of the biosensor for visualization of epileptic seizures. Collectively, these data make fluoroionophore FI3 a versatile cross‐platform fluorescent biosensor, broadly compatible with diverse experimental models, and crown‐ether‐based polymer nanoparticles can provide a new venue for the design of efficient fluorescent probes.     

Photon-drag effect in single-walled carbon nanotube films

We observed an interaction of single-walled carbon nanotube films with obliquely incident nanosecond laser radiation in visible and infrared regions generating unipolar voltage pulses replicating the shape of the laser pulses. The photoelectric signal significantly depends on the laser polarization and has maximum value at the laser beam incidence angle of ±65° and at the film thickness of 350 nm. The results are explained in the framework of the photon-drag effect.