Physicochemical Characterization and Paper Spray Mass Spectrometry Analysis of Myrciaria Floribunda (H. West ex Willd.) O. Berg Accessions

Myrciaria floribunda, also known as rumberry, is a tree native to the Brazilian Atlantic Forest, where its fruits have the potential for commercial use. This study evaluates the antioxidant potential, determines the phytochemical profile, and chemically characterizes the rumberry fruit. Accessions were sampled from the Rumberry Active Germplasm Bank of the Federal University of Alagoas, Brazil. Physical characteristics, chemical characteristics, and phenolic compound content were analyzed. Chemical profile characterization was carried out using PSMS. Accessions had an average weight of 0.86 g. Accession AC137 presented a higher pulp yield (1.12 g). AC132 and AC156 had larger fruits, AC137 showed greater firmness (5.93 N), and AC160 had a higher and total phenolic content ratio (279.01 ± 11.11). Orange-colored accessions scored higher in evaluated parameters, except for AC160 for phenolic content. Thirty-two compounds were identified on positive ionization mode and 42 compounds on negative ionization mode using PSMS. Flavonoids, followed by the derivatives of benzoic acid, sugars, and phenylpropanoids, were the most prominent. Myricitrin, quercitrin, and catechin stand out as flavonoids that have been reported in previous studies with antioxidant and antimicrobial properties, in addition to health and therapeutical benefits, demonstrating the potential of the rumberry fruit.     

Predicting adsorption isotherms of asphaltenes in porous materials

In this paper we present a molecular thermodynamics approach for the modeling of adsorption isotherms of asphaltenes adsorbed on Berea sandstone, Bedford limestone and dolomite rock, using a model for bulk asphaltenes precipitation and a quasi-two-dimensional approach for confined fluids [E. Buenrostro-González, C. Lira-Galeana, A. Gil-Villegas, J. Wu, AIChE J., 50 (2004) 2552–2570; A. Martínez, M. Castro, C. McCabe A. Gil-Villegas, J. Chem. Phys. 126 (2007) 074707, respectively], both based on the Statistical Associating Fluid Theory for Potentials of Variable Range [A. Gil-Villegas, A. Galindo, P.J. Whitehead, S.J. Mills, G. Jackson, A.N. Burgess, J. Chem. Phys. 106 (1997) 4168–4186]. The theory is applied to model adsorption isotherms from experimental data of asphaltenes extracted from a dead sample of heavy crude oil from a Mexican reservoir. The theoretical results give the right Langmuir Type II adsorption isotherms observed experimentally. The model requires the determination of ten molecular parameters related to the size of the particles and the square-well potentials used to describe the particle–surface and particle–particle interactions at the bulk and adsorbed phases. Nine parameters are taken from previous published results about the behavior of asphaltenes in bulk phases and the adsorption of several molecular fluids onto activated carbon and graphite surfaces. The remaining parameter, the energy strength of the particle–surface interaction, is adjusted to reproduce the experimental data, obtaining values that are consistent with Molecular Mechanics calculations for asphaltenes adsorbed on different surfaces and solutions. Although the agreement between theory and experiments shows some deviations at low bulk concentrations, the model reproduces adsorption data at high concentrations where other semi-empirical approaches fail.     

Genetic individualization of <Emphasis Type="Italic">Cannabis sativa</Emphasis> by a short tandem repeat multiplex system

Cannabis sativa is the most frequently used of all illicit drugs in the USA. Cannabis has been used throughout history for its stems in the production of hemp fiber, seed for oil and food, and buds and leaves as a psychoactive drug. Short tandem repeats (STRs) were chosen as molecular markers owing to their distinct advantages over other genetic methods. STRs are codominant, can be standardized such that reproducibility between laboratories can be easily achieved, have a high discrimination power, and can be multiplexed. In this study, six STR markers previously described for C. sativa were multiplexed into one reaction. The multiplex reaction was able to individualize 98 cannabis samples (14 hemp and 84 marijuana, authenticated as originating from 33 of the 50 states of the USA) and detect 29 alleles averaging 4.8 alleles per loci. The data did not relate the samples from the same state to each other. This is the first study to report a single-reaction sixplex and apply it to the analysis of almost 100 cannabis samples of known geographic origin. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Histamine Molecule and Dianion Oxalate are Efficient Blocks for Building 2D Supramolecular Networks

Abstract  

One salt and two Cu(II) complexes (H₂hsm)(ox), 1, [Cu(hsm)(ox)], 2, and [Cu(hsm)(ox)H₂O], 3, have been synthesized and X-ray characterized (hsm is histamine and ox²⁻ is the oxalate dianion). Starting from the prochiral tetracoordinated complex 2, pentacoordinated complex 3 crystallizes as a racemic mixture of the enantiomeric Δ and Λ isomers, in space group P2₁/c. In all cases, the side chain of the hsm group is gauche, allowing the formation of strong hydrogen bonds in the salt 1, and to chelate the metal center in complexes 2 and 3. The combination hsm/ox seems to favor the formation of 2D supramolecular structures (planes or wavy planes), through efficient networks of N–H···O hydrogen bonds. Cell parameters: 1, P2₁/c, a = 6.260 (2) ?, b = 11.500 (4) ?, c = 12.525 (4) ?, β = 104.047 (17)o; 2, C2/c, a = 10.7966 (13) ?, b = 15.5622 (16) ?, c = 11.3996 (15) ?, β = 106.261 (11)o; 3, P2₁/c, a = 7.0627 (6) ?, b = 7.1323 (6) ?, c = 20.0296 (19) ?, β = 91.529 (7)o.     

Shamrock surfactants with terminal carboxylate headgroups and a central phosphorodithioate or quaternary ammonium headgroup

Surfactants 3 (tripotassium O,O'-di-[11-(carboxylato)undecyl]phosphorodithioate) and 4 (sodium 12-[dimethyl-(11-carboxylatoundecyl)ammonio]dodecanoate), which are new shamrock surfactants, were prepared and characterized. Shamrock surfactants represent a novel class of surfactants that contain a central headgroup connected to two flanking headgroups by hydrocarbon chains; they do not contain long-chain alkyl groups. Surfactants 3 and 4 were characterized in water by measurement of their Krafft temperatures and critical aggregation concentrations, and their aggregates were studied by 1H and 31P NMR spectroscopy, dynamic laser light scattering, and phase-contrast optical microscopy. Aqueous 3 and 4 were also studied by cryoetch high-resolution scanning electron microscopy, which revealed fences with interposed lacelike patterns for the former and compartments formed by irregular fences for the latter. Coacervates were likely formed upon the undisturbed hydration of 3 and 4, as determined by phase-contrast optical microscopy.     

Chemical Physical Characterization and Profile of Fruit Volatile Compounds from Different Accesses of Myrciaria floribunda (H. West Ex Wild.) O. Berg through Polyacrylate Fiber

Among the many species of native fruit of Brazil that have been little explored, there is Myrciaria floribunda (also known as rumberry, cambuizeiro, or guavaberry), a species with significant variability, which has fruits of different colors (orange, red, and purple) when ripe. The physical-chemical characteristics evaluated were fruit weight (FW), seed weight (SW), pulp weight (PW), number of seeds (NS), longitudinal diameter (LD), transverse diameter (TD), format (LD/TD), hydrogen potential (pH), soluble solids (SS), titratable acidity (TA), and ratio (SS/TA); further, the volatile organic compounds (VOCs) of nine accesses of rumberry orchards were identified. The averages of the variables FW, SW, PW, NS, LD, TD, shape, and firmness were 0.76 g, 0.22 g, 0.54 g, 1.45, 10.06 mm, 9.90 mm, 1.02, 2.96 N, respectively. LD/TD data showed that the fruits have a slightly rounded shape (LD/TD = 1). The averages for pH, SS, TA, and SS/TA were 3.74, 17.58 Brix, 4.31% citric acid, and 4.31, respectively. The evaluated parameters indicated that the fruits can be consumed both in natura and industrialized, with the red-colored fruits presenting a good balance of SS/TA, standards demanded by the processing industries. Thirty-six VOCs were identified, with emphasis on the sesquiterpenes. Caryophyllene (21.6% to 49.3%) and γ-selinene (11.3% to 16.3%) were the most predominant compounds in rumberry fruits.     

Editorial

More than 30 years of scientific endeavor have brought us from programming simple models to impressive simulations of dynamic systems. Lattice models like Potts, percolation, fuse, fiber bundle, and growth models, just to name a few, are the prototypes or godfathers of statistical mechanics. With the availability of more powerful tools it became possible to develop these models and apply them on complex topologies, finding important practical applications in socio-technological systems (e.g., opinion dynamics, traffic, communication networks) and to engineering problems (e.g., fracture phenomena, mass transport). In parallel, particle models evolved from a hand full of interacting discs to three dimensional multibillion particle simulations that successfully describe interesting fracture phenomena, granular flow, and even fluid flow for engineering applications. Prof. Dr. Hans Jürgen Herrmann has dedicated his professional life to this journey.     

Relativistic lattice kinetic theory: Recent developments and future prospects

In this paper, we review recent progress in relativistic lattice kinetic theory and its applications to relativistic hydrodynamics. Two methods for constructing the discretised distribution function, moment matching and projection onto orthogonal polynomials, are described. Extensions to ultra-high velocities as well as improved dissipation models are discussed. We show that the existing models can successfully cover a wide range of velocities (from weak-relativistic to ultra-relativistic) and viscous regimes. Various applications, from quark-gluon plasma and relativistic Richtmyer-Meshkov instability to flows in curved manifolds are also explored. Finally, potential developments for general relativity are outlined along with future prospects for solving the full set of Einstein equations of general relativity.     

Metamagnetism and weak ferromagnetism in nickel (II) oxalate crystals

Microcrystals of orthorhombic nickel (II) oxalate dihydrate were synthesized through a precipitation reaction of aqueous solutions of nickel chloride and oxalic acid. Magnetic susceptibility exhibits a sharp peak at 3.3 K and a broad rounded maximum near 43 K. We associated the lower maximum with a metamagnetic transition that occurs when the magnetic field is about ≥3.5 T. The maximum at 43 K is typical of 1D antiferromagnets, whereas weak ferromagnetism behavior was observed in the range of 3.3–43 K.