What is the most effective way of increasing the bioavailability of dietary long chain omega-3 fatty acids-daily vs. weekly administration of fish oil?

The recommendations on the intake of long chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) vary from eating oily fish ("once to twice per week") to consuming specified daily amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ("250-500 mg per day"). It is not known if there is a difference in the uptake/bioavailability between regular daily consumption of supplementsvs. consuming fish once or twice per week. In this study, the bioavailability of a daily dose of n-3 LC-PUFA (Constant treatment), representing supplements, vs. a large weekly dose of n-3 LC-PUFA (Spike treatment), representing consuming once or twice per week, was assessed. Six-week old healthy male Sprague-Dawley rats were fed either a Constant treatment, a Spike treatment or Control treatment (no n-3 LC-PUFA), for six weeks. The whole body, tissues and faeces were analysed for fatty acid content. The results showed that the major metabolic fate of the n-3 LC-PUFA (EPA+docosapentaenoic acid (DPA) + DHA) was towards catabolism (β-oxidation) accounting for over 70% of total dietary intake, whereas deposition accounted less than 25% of total dietary intake. It was found that significantly more n-3 LC-PUFA were β-oxidised when originating from the Constant treatment (84% of dose), compared with the Spike treatment (75% of dose). Conversely, it was found that significantly more n-3 LC-PUFA were deposited when originating from the Spike treatment (23% of dose), than from the Constant treatment (15% of dose). These unexpected findings show that a large dose of n-3 LC-PUFA once per week is more effective in increasing whole body n-3 LC-PUFA content in rats compared with a smaller dose delivered daily

Relaxation effects in twisted bilayer molybdenum disulfide: structure, stability, and electronic properties

Manipulating the interlayer twist angle is a powerful tool to tailor the properties of layered two-dimensional crystals. The twist angle has a determinant impact on these systems' atomistic structure and electronic properties. This includes the corrugation of individual layers, formation of stacking domains and other structural elements, and electronic structure changes due to the atomic reconstruction and superlattice effects. However, how these properties change with the twist angle (ta) is not yet well understood. Here, we monitor the change of twisted bilayer MoS2 characteristics as function of ta. We identify distinct structural regimes, with particular structural and electronic properties. We employ a hierarchical approach ranging from a reactive force field through the density-functional-based tight-binding approach and density-functional theory. To obtain a comprehensive overview, we analyzed a large number of twisted bilayers with twist angles in the range 0.2-59.6deg. Some systems include up to half a million atoms, making structure optimization and electronic property calculation challenging. For 13<ta<47, the structure is well-described by a moir\'e regime composed of two rigidly twisted monolayers. At small ta (ta<3 and 57<ta), a domain-soliton regime evolves, where the structure contains large triangular stacking domains, separated by a network of strain solitons and short-ranged high-energy nodes. The corrugation of the layers and the emerging superlattice of solitons and stacking domains affects the electronic structure. Emerging predominant characteristic features are Dirac cones at K and kagome bands. These features flatten for ta approaching 0 and 60deg. Our results show at which ta range the characteristic features of the reconstruction emerge and give rise to exciting electronics. We expect our findings also to be relevant for other twisted bilayer systems

Wave Propagation in Periodic Metallic Structures with Equilateral Triangular Holes

This paper studies wave propagation in a periodic parallel-plate waveguide with equilateral triangular holes. A mode-matching method is implemented to analyze the dispersion diagram of the structure possessing glide and mirror symmetries. Both structures present an unexpected high degree of isotropy, despite the triangle not being symmetric with respect to rotations of 90º. We give some physical insight on the matter by carrying out a modal decomposition of the total field on the hole and identifying the most significant modes. Additionally, we demonstrate that the electrical size of the triangular hole plays a fundamental role in the physical mechanism that causes that isotropic behavior. Finally, we characterize the influence of the different geometrical parameters that conform the unit cell (period, triangle size, hole depth, separation between metallic plates). The glide-symmetric configuration offers higher equivalent refractive indexes and widens the stopband compared to the mirror-symmetric configuration. We show that the stopband is wider as the triangle size is bigger, unlike holey structures composed of circular and elliptical holes where an optimal hole size exists.This work was partially funded by the Spanish Ministerio de Ciencia Innovación y Universidades under the project TIN2016-75097-P, and with European Union FEDER funds under projects TEC2017-84724-P and TEC2017-85529-C3-1-R, by the French National Research Agency Grant Number ANR-16-CE24-0030, by the Vinnova project High-5 (2018-01522) under the Strategic Programme on Smart Electronic Systems, and by the Stiftelsen Åforsk project H-Materials (18-302)

Dielectric, piezoelectric and electrical study of 0.65PMN-0.20PZT-0.15PT relaxor ceramic

The dielectric, piezoelectric and electrical properties of relaxor ferroelectric 0.65PMN-0.20PZT-0.15PT ceramic as a function of sintering temperatures was investigated. X-ray diffraction shows that with increasing temperature from 700 °C to 800 °C the pyrochlore unwanted phase reduces and at 850 °C the single phase of perovskite be formed. The studies and reviews reveal that the outstanding electrical properties are obtained with this composition near the morphotropic phase boundary (MPB). P-E hysteresis loops emphasize that the synthesis optimum temperature is 1250 °C and observed that the best temperature that led to improved properties of dielectric constant, polarization and piezoelectric coefficients is this temperature

Effect of different dopants Ba and Ag on the properties of SrTiO3 nanopowders

Undoped and Ba and Ag-doped SrTiO3-based nanopowders (NPs) were successfully grown by a modified auto-combustion method. An optimum ratio of citric acid and nitric acid was used as the polymerization agent and fuel. The X-ray diffraction (XRD) results revealed that the products were crystalline with cubic and tetragonal structures. The particle aggregation state, nanoparticles size distribution, morphology and electrical properties were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), atomic force microscopy (AFM) and ultraviolet–visible (UV–vis) were studied, respectively. Using the X-ray peak broadening and size–strain plot (SSP) method the crystallite sizes and lattice strain of the samples were investigated. The UV–vis absorption spectra revealed that the band gap of the STO-based has a strong absorption peak which lies in the UV region

Structural and optical characterization of folate-conjugated gold-nanoparticles

Gold nanoparticles (AuNPs) represent a novel nanomaterials applied in various nanotechnology fields because of their special optical properties. On the other hand, folic acid and folate can be used for selective targeting of nanoparticles towards cancer cells. Folate conjugated AuNPs can be considered as an effective nanoconjugate in the field of nanotargeted photothermal therapy of cancer. In the present work, we report our synthesis of a new nanoconjugate composed of folate, AuNP and 4-aminothiophenol (4Atp) as the linker and named Folate-4Atp-AuNP. The results of our investigations on properties of this new nanoconjugate are presented here including the effects of addition of folate and 4Atp to AuNP on its structural and optical properties. We studied the structural characteristics of Folate-4Atp-AuNP using X-ray diffraction. In addition, we determined its optical band gap energy (1.365 eV), its optical constants using Kramers-Kronig analysis and we identified its metallic face-centered cubic (fcc) lattice structure and particular crystal planes. Our findings indicate that the presence of 4Atp and folate in Folate-4Atp-AuNP had no significant effect on its optical band gap energy. However, some appreciable changes in its optical constants were observed due to the presence of 4Atp and folate in nanoconjugate. The significant changes in optical constants values are apparently as a result of the presence of some special bonds and a few particular functional groups in the nanoconjugate. © 2009 Elsevier B.V. All rights reserved

Implementing electronic signatures of graphene and hexagonal boron nitride in twisted bilayer molybdenum disulfide

Angeli and MacDonald reported a superlattice-imposed Dirac band in twisted bilayer molybdenum disulphide (tBL MoS2) for small twist angles towards the R_h^M (parallel) stacking. Using a hierarchical set of theoretical methods, we show that the superlattices differ for twist angles with respect to metastable R_h^M (0°) and lowest-energy H_h^h (60°) configurations. When approaching R_h^M stacking, identical domains with opposite spatial orientation emerge. They form a honeycomb superlattice, yielding Dirac bands and a lateral spin texture distribution with opposite-spin-occupied K and K’ valleys. Small twist angles towards the H_h^h configuration (60°) generate H_h^h and H_h^X stacking domains of different relative energies and, hence, different spatial extensions. This imposes a symmetry break in the moiré cell, which opens a gap between the two top-valence bands, which become flat already for relatively small moiré cells. The superlattices impose electronic superstructures resembling graphene and hexagonal boron nitride into trivial semiconductor MoS2