Plasma Lipid Profiling Contributes to Untangle the Complexity of Moyamoya Arteriopathy

Moyamoya arteriopathy (MA) is a rare cerebrovascular disorder characterized by ischemic/hemorrhagic strokes. The pathophysiology is unknown. A deregulation of vasculogenic/angiogenic/inflammatory pathways has been hypothesized as a possible pathophysiological mechanism. Since lipids are implicated in modulating neo-vascularization/angiogenesis and inflammation, their deregulation is potentially involved in MA. Our aim is to evaluate angiogenic/vasculogenic/inflammatory proteins and lipid profile in plasma of MA patients and control subjects (healthy donors HD or subjects with atherosclerotic cerebrovascular disease ACVD). Angiogenic and inflammatory protein levels were measured by ELISA and a complete lipidomic analysis was performed on plasma by mass spectrometry. ELISA showed a significant decrease for MMP-9 released in plasma of MA. The untargeted lipidomic analysis showed a cumulative depletion of lipid asset in plasma of MA as compared to HD. Specifically, a decrease in membrane complex glycosphingolipids peripherally circulating in MA plasma with respect to HD was observed, likely suggestive of cerebral cellular recruitment. The quantitative targeted approach demonstrated an increase in free sphingoid bases, likely associated with a deregulated angiogenesis. Our findings indicate that lipid signature could play a central role in MA and that a detailed biomarker profile may contribute to untangle the complex, and still obscure, pathogenesis of MA.     

Characterization of Anadenanthera macrocarpa exudate polysaccharide

Exudate gum from Anadenanthera macrocarpa Benth. trees was purified and fractionated using 0·1M aq. NaCl/ethanol as a solvent/non-solvent system. The composition of the polysaccharide was determined as 67% arabinose, 24% galactose, 2% rhamnose and 7% glucuronic acid, by a combination of high performance liquid chromatography of fully hydrolysed gum and colorimetric analysis of uronic acid. Molecular characteristics of the polysaccharide and its fractions were investigated by light scattering intensity, dilute solution visco-metry and gel permeation chromatography (GPC). The whole gum was shown to possess a broad molar mass distribution with Mw = 3·7×10⁶ g mol^-1 and [η] = 11cm³ g^-1. Hydrodynamic properties indicated a highly branched structure. Fractions were obtained covering a range of molar masses. The intrinsic viscosity in 1·0 M aq. NaCl at 25°C was found to depend on molar mass according to: [η]/cm³ g^-1 =0 ·0145 M^0·44. The hydrodynamic volume parameter [η]M gave a common GPC calibration for branched polysaccharide fractions and linear poly(oxyethylene) standards. ©1997 SCI     

Low-density polyethylene modified by thermal polymerization of 4-vinylpyridine and methyl methacrylate: Structural studies

The structures of low-density polyethylene (LDPE) modified by in situ sorption and thermal polymerization of 4-vinylpyridine (4VP) and of methyl methacrylate (MMA) were studied. The phase behavior of these materials was investigated by means of X-ray diffraction, scanning electron microscopy (SEM), and by thermal measurements (DSC). The diffraction studies indicated that the polymerization occurs at the amorphous domains of the matrix, except for the case of 4VP (168.0%), in which polymerization at the crystalline domains of LDPE matrix was also observed. These materials showed at least two T_g values, indicating microphase separation. The morphology of LDPE-P4VP was different from that of LDPE-PMMA.     

Development of active cassava starch cellulose nanofiber-based films incorporated with natural antimicrobial tea tree essential oil

In the present study, a cassava starch-glycerol film with reinforcement of Pinus sp. nanofibers (NFC) incorporated with tea tree (Melaleuca alternifolia) essential oil (TTO) were prepared by casting technique. The physical (barrier, mechanical, and optical), structural, and antimicrobial properties of the films were evaluated and compared with the control films. Films with 0.08% TTO exhibited a significant increase in the tensile strength (TS) while films with 1.5% TTO showed a decrease in TS, suggesting a crosslinking effect. The addition of 1.5% TTO reduced the water vapor permeability values in 43% comparing to the control films. Analysis obtained by Fourier transform infrared spectroscopy showed bands related to the interaction between TTO and matrix for films with 1.5% TTO and 0.3% NFC. This film was effective against Staphylococcus aureus and Candida albicans which could be applied for several packaging purposes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48726.     

Carbon fiber-embedded bacterial cellulose/polyaniline nanocomposite with tailored for microbial fuel cells electrode

Microbial fuel cells (MFC) are of great interest for new sources of renewable energies from the waste of biomass and debris. This work aimed was to develop an anode electrode of the carbon fiber-embedded of bacterial cellulose/polyaniline (CF/BC/PANI) nanocomposite for MFC applications. For this purpose, carbon fiber was wrapped onto bacterial cellulose (BC) fibers network during the BC synthesis. The CF/BC/PANI was obtained by polyaniline polymerization on the BC nanofibers as a scaffold. To characterize the electrode, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis analysis were carried out. The electrical conductivity was determined by measuring the resistivity. MFC using the CF/BC/PANI electrode was monitored and the maximum current density generated was 0.009 mA/cm². The results obtained from the CF/BC/PANI demonstrate great potential for the use as an MFC electrode, as well as a microenvironment favorable to a microbial biofilm formation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Naphthalene Containing Poly(urethane‐urea) for Volatile Memory Device Applications

Current or voltage controlled electrical switching in organic molecules and polymers is attracting attention due to its potential in organic electronic memory applications. The switching phenomenon under consideration in this article is characterized as a sudden transition from a low to a high conductivity condition at a threshold voltage. For the observed volatile switching phenomenon, the lower conductivity condition is restored as soon as the applied voltage becomes smaller than a holding voltage. This switching phenomenon presents the basic requirements for application in volatile memory devices. In this Communication we report on volatile electrical switching observed in a polyurethane derivative copolymerized with diaminonaphthalene.     

The Reductive Amination of Aldehydes and Ketones and the Hydrogenation of Nitriles: Mechanistic Aspects and Selectivity Control

This review deals with two of the most commonly used methods for the preparation of amines: the reductive amination of aldehydes and ketones and the hydrogenation of nitriles. There is a great similarity between these two methods, since both have the imine as intermediate. However, due to the high reactivity of this intermediate, primary, secondary and/or tertiary amines are obtained (often simultaneously). The relation of the selectivity to different substrate structures and reaction conditions is briefly summarised, the main focus being on the catalyst as it is the most significant factor that governs the selectivity. Different mechanisms are discussed with the view to correlate the structure of the catalyst and, more particularly, the nature of the metal and the support with selectivity. The crucial point is the presumed location of the condensation and hydrogenation steps.     

Mechanisms of Solid–Gas Reactions: Reduction of Air Pollutants on Carbons

Topics in Catalysis - Ozone is a strong oxidizer and sulfur dioxide is a precursor to acid rain, both are air pollutants that can damage the respiratory tissues of animals and plants making them...