Multidimensional simple waves in fully relativistic fluids

A special version of multi--dimensional simple waves given in [G. Boillat, {\it J. Math. Phys.} {\bf 11}, 1482-3 (1970)] and [G.M. Webb, R. Ratkiewicz, M. Brio and G.P. Zank, {\it J. Plasma Phys.} {\bf 59}, 417-460 (1998)] is employed for fully relativistic fluid and plasma flows. Three essential modes: vortex, entropy and sound modes are derived where each of them is different from its nonrelativistic analogue. Vortex and entropy modes are formally solved in both the laboratory frame and the wave frame (co-moving with the wave front) while the sound mode is formally solved only in the wave frame at ultra-relativistic temperatures. In addition, the surface which is the boundary between the permitted and forbidden regions of the solution is introduced and determined. Finally a symmetry analysis is performed for the vortex mode equation up to both point and contact transformations. Fundamental invariants and a form of general solutions of point transformations along with some specific examples are also derived.Comment: 21 page

Foam-Mat Freeze-Drying of Blueberry Juice by Using Trehalose-β-Lactoglobulin and Trehalose-Bovine Serum Albumin as Matrices

This study aimed to evaluate the effect of pure protein compounds and trehalose incorporated into blueberry juice for foam-mat freeze-drying on the foam and powder properties. Foam-mat freeze-drying (FMFD) of blueberry juice was tested at − 55 °C for 24 h. Matrices used were trehalose + β-lactoglobulin (T3BL1) and trehalose + bovine serum albumin (T3A1) and compared with maltodextrin + whey protein isolate (M3W1). Physicochemical properties of foam and powder, e.g., foam stability, foam density, moisture, rehydration time, color, particle morphology, total phenolic, and anthocyanins (total and individuals), were investigated. T3BL1 and T3A1 had more stable foam than M3W1. However, overrun of T3BL1 and T3A1 foamed were inferior to the M3W1 sample. The M3W1 sample recovered 79% powder (dry weight) and was superior to others. Rehydration time of powdered T3BL1 and T3A1, with bulk densities of 0.55–0.60 g cm−3, was the fastest (34–36 s). The blueberry powders of M3W1 showed more irregular particle size and shape, while the samples with trehalose and pure proteins generated particles of more uniform size with obvious pores. T3BL1 and T3A1 showed less redness (a*) values than the M3W1 product. All samples were considered pure red due to hue values < 90. M3W1 was superior in total phenolic content (TPC) and total monomeric anthocyanins (TMA) compared with both samples made with trehalose + β-lactoglobulin and trehalose+bovine serum albumin. Delphinidin-3-glucoside (Del3Gl) concentration was found to be higher in M3W1. Also, M3W1 had higher cyanidin-3-glucoside (Cyn3Gl) and malvidin-3-glucoside (Mal3Gl) concentration. M3W1 also prevented the degradation of these bioactive compounds better than the other FMFD samples. The use of pure proteins and trehalose as matrices in the FMFD process had little advantage compared with maltodextrin/whey protein isolate. Thus, maltodextrin/whey protein isolate seems an ideal matrix for the manufacture of FMFD blueberry

Computational investigation on CO2 capturing capacity of N-doped and Na-decorated Graphdiyne

International audienceGraphdiyne (GDY) is a newly discovered member of the two-dimensional carbon allotropes that has been proposed as a material for carbon dioxide (CO2) capture and storage technology. The GDY structure is composed of several hybridized carbon atoms, and despite its superior electronic capabilities, modifying its structure can facilitate the advancement of its practical applications. This study considered, N-doping, Na-decoration, and their combinations as GDY modifications. The dispersion-corrected density functional theory (DFT-D2) approach was used to investigate the structural and electronic properties of the resultant adsorbents and their CO2 adsorption behavior. Among three different N-doped structures, substituting an N atom for the Carbon with hybridization of SP 2-SP (CSP 2-SP) produced the most stable N-doped GDY with Ecoh =-7.23eV. Four different locations of GDY were decorated by Na atom, and the center of the H3 was identified as the most stable site with Eads =-3.804eV. This site was also the most favorable for Na decorating of the N-doped GDY, with Eads =-3.347eV. Moreover, the results indicated that when a single CO2 was adsorbed on the Na-decorated GDY, the adsorption energy was-0.432eV, the highest value among the pristine and modified structures. However, evaluation of the maximum CO2 capturing capacity of the systems revealed that Ndoped GDY could capture eleven CO2 molecules, ca. 68.92 Wt%, which makes it a potential candidate for future CO2 capture, storage, detection, and removal applications

Investigation of Mechanical, Thermal, Electrical, and Hydrogen Diffusion Properties in Ternary V-Ti-X Alloys: A Density Functional Theory Study

The effects of alloying and hydrogen dissolution on the mechanical, thermal, and electrical properties of vanadium-based ternary alloys were investigated using density functional theory. Our study showed that pure V has a lower solution energy than V-Ti-X alloys. Also, tetrahedral interstitial sites are more favorable than octahedral sites to be occupied by the H atoms. Furthermore, the alloys with eight H atoms have a lower capacity than the pure V system for H-trapping at interstitial sites. These findings suggest that H-dissolution in alloys is less probable than in pure V, and the alloys are more resistant to hydrogen embrittlement, crack propagation, and fracture initiation. Indeed, V-Ti-Al shows a reliable performance and could be a viable non-Pd alloy for hydrogen separation. Studying the mechanical properties of pure V and the ternary alloys revealed that V-Ti-Ni provides the highest durability and better resistance to both external and hydrogen dissolution-induced internal stresses. The V-Ti-Pd alloy has a higher diffusion barrier energy (Eb = 0.1807 eV) than pure V (Eb = 0.1646 eV), indicating that the H atom faces more hindrance when it diffuses across the alloy. Nonetheless, in the hydrogen separation temperature range, the V-Ti-Pd alloy has the largest thermal expansion coefficient (α = 2.048×10-5 K-1), which indicates its poor thermal characteristics. Altogether, the superior mechanical properties of the V-Ti-Ni alloy indicate that it will be resistant to deformation and have a long service life in hydrogen separation applications. The V-Ti-Ni alloy has a higher heat capacity than the others, which is important in exothermic processes like hydrogen separation.H.A. and M.A.B. are grateful to the Research Council of the Shahid Beheshti University and Lorestan University, respectively.Peer reviewe

Interaction of β-Lactoglobulin with Resveratrol: Molecular Docking and Molecular Dynamics Simulation Studies

In this work, the interaction of trans-resveratrol, as a natural polyphenolic compound, and Bovine β-lactoglobulin (BLG), was studied using molecular docking and molecular dynamics simulation methods. The molecular dynamics study makes an important contribution to understanding the effect of the binding of resveratrol on conformational changes of BLG and the stability of a protein-drug complex system in aqueous solution. Molecular docking studies revealed that the resveratrol was bound to the surface of the protein by two hydrogen bond interactions. The binding constant and free energy change, ΔG°, for the binding of resveratrol to BLG were about 6.6 × 105 mol L–1 and –33.4 kJ mol–1, respectively. Furthermore, the results of molecular dynamics simulation represented that the rmsd of unliganded BLG and BLG-resveratrol complex reached equilibration and oscillated around the average value after 600 ps simulation time. The study of the radius of gyration (Rg) revealed that BLG and BLG-resveratrol complexes were stabilized around 1500 ps and also exhibited no conformational change. Finally, analyzing the rms fluctuations suggested that the structure of the ligand binding site remains approximately rigid during the simulation

A multi-scale modelling of an enzymatic PET degradation.

International audienc

Tris-chelated complexes of nickel(II) with bipyridine derivatives: DNA binding and cleavage, BSA binding, molecular docking, and cytotoxicity

<p>Two nickel(II) complexes with substituted bipyridine ligand of the type [Ni(NN)₃](ClO₄)₂, where NN is 4,4′-dimethyl-2,2′-bipyridine (dimethylbpy) (<b>1</b>) and 4,4′-dimethoxy-2,2′-bipyridine (dimethoxybpy) (<b>2</b>), have been synthesized, characterized, and their interaction with DNA and bovine serum albumin (BSA) studied by different physical methods. X-ray crystal structure of <b>1</b> shows a six-coordinate complex in a distorted octahedral geometry. DNA-binding studies of <b>1</b> and <b>2</b> reveal that both complexes sit in DNA groove and then interact with neighboring nucleotides differently; <b>2</b> undergoes a partial intercalation. This is supported by molecular-docking studies, where hydrophobic interactions are apparent between <b>1</b> and DNA as compared to hydrogen bonding, hydrophobic, and <i>π–π</i> interactions between <b>2</b> and DNA minor groove. Moreover, the two complexes exhibit oxidative cleavage of supercoiled plasmid DNA in the presence of hydrogen peroxide as an activator in the order of <b>1 </b>><b> 2</b>. In terms of interaction with BSA, the results of spectroscopic methods and molecular docking show that <b>1</b> binds with BSA only via hydrophobic contacts while <b>2</b> interacts through hydrophobic and hydrogen bonding. It has been extensively demonstrated that the nature of the methyl- and methoxy-groups in ligands is a strong determinant of the bioactivity of nickel(II) complexes. This may justify the above differences in biomolecular interactions. In addition, the <i>in vitro</i> cytotoxicity of the complexes on human carcinoma cells lines (MCF-7, HT-29, and U-87) has been examined by MTT assay. According to our observations, <b>1</b> and <b>2</b> display cytotoxicity activity against selected cell lines.</p> <p></p> <p>Communicated by Ramaswamy H. Sarma</p