282 research outputs found
Valorization of Tomato Processing by-Products: Fatty Acid Extraction and Production of Bio-Based Materials
A method consisting of the alkaline hydrolysis of tomato pomace by-products has been optimized to obtain a mixture of unsaturated and polyhydroxylated fatty acids as well as a non-hydrolysable secondary residue. Reaction rates and the activation energy of the hydrolysis were calculated to reduce costs associated with chemicals and energy consumption. Lipid and non-hydrolysable fractions were chemically (infrared (IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS)) and thermally (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)) characterized. In addition, the fatty acid mixture was used to produce cutin-based polyesters. Freestanding films were prepared by non-catalyzed melt-polycondensation and characterized by Attenuated Total Reflected-Fourier Transform Infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (NMR), DSC, TGA, Water Contact Angles (WCA), and tensile tests. These bio-based polymers were hydrophobic, insoluble, infusible, and thermally stable, their physical properties being tunable by controlling the presence of unsaturated fatty acids and oxygen in the reaction. The participation of an oxidative crosslinking side reaction is proposed to be responsible for such modifications.Andalusian Regional Government P11-TEP-7418Spanish Ministerio de Economía y Competitividad AGL2015-65246-R and AGL2017-83036-RFondo Europeo de Desarrollo Regional (FEDER) AGL2015-65246-R and AGL2017-83036-
Deciphering the unique structure and acylation pattern of Posidonia oceanica lignin
Copyright © 2020 American Chemical Society. Lignins from different parts of the seagrass Posidonia oceanica-namely sheaths, rhizome, and roots-as well as from fibrous balls from P. oceanica detritus were isolated and thoroughly characterized by pyrolysis coupled with gas chromatography/mass spectrometry, derivatization followed by reductive cleavage, two-dimensional nuclear magnetic resonance spectroscopy, and gel permeation chromatography. The lignins of P. oceanica were enriched in guaiacyl (G) over syringyl (S) units, with S/G ratios ranging from 0.1 (fibrous balls) to 0.5 (rhizome). β-O-4′ ethers and phenylcoumarans were the most abundant lignin substructures, followed by resinols, and minor amounts of dibenzodioxocins and spirodienones. Moreover, all lignins were found to be highly I-Acylated (up to 44% of total units), mainly with p-hydroxybenzoates but also, to a lesser extent, with acetates. The data indicated that this acylation extensively occurred in both G-and S-lignin units, contrary to what happens in palms, poplar, and willow, where p-hydroxybenzoates overwhelmingly appear at the I-position of S-units
Results of the 2004 Spanish Experimental Fishing in NAFO Subarea 1
An experimental fishing was carried out with three bottom trawlers commercial Spanish vessels from July to December
of the year 2004 in the Subarea 1. The main objective of the experimental fishing was to search for cephalopods species
concentrations inside the territorial waters of Greenland. During the experimental fishing a scientific observer stayed on
board each vessel to collect effort data, catches and yields by haul and Division. The observers carried out length
distribution samplings of the following species: Reinhardtius hippoglossoides, Pandalus borealis, Gadus morhua,
Sebastes spp., Hippoglossoides platessoides and Macrourus berglax. Biological samplings of R. hippoglossoides, P.
borealis, H. platessoides, G. morhua and M. berglax were also carried out. Otoliths of Greenland halibut (1 356) and
Atlantic cod (739) were collected for age determination. Greenland halibut was the main species caught and the
cephalopods, target species, have not been found in the experimental fishing
Indicative value of the dominant plant species for a rapid evaluation of the nutritional value of soils
A study was conducted on 14 grassland communities located in the south of the Iberian
Peninsula and their edaphology, which is identified as specific plant associations. The edaphic
study of each association allows a rapid evaluation of the nutrient content in the soil without the
need for laboratory edaphic analysis. For each phytosociological relevé and soil, samplings were
carried out. The field data were subjected to various statistical analysis—canonical correspondence
analysis (CCA), Bayesian networks, and decision trees—to establish nutrient content. When the
abundance value of the species is 9 in the Van der Maarel scale, there is an increase in the values
of several soil parameters. In the case of Hordeum leporinum, when the Van der Maarel index is 9,
the Kc (exchangeable potassium in cmol/kg) undergoes the greatest variation, to a value of up to
0.729 cmol/kg. The application of the decision tree to this species reveals that the soil attributes with
the greatest influence in the classification are conductivity, %_si (silt texture), pH, and pF 15 atm
(pressure at 15 atmospheres (water retention capacity) in %). Indeed, this interlaced edaphic and
phytosociological study provides us with a high-value tool to obtain quick information on the content
of nutrients in the soil.info:eu-repo/semantics/publishedVersio
Shaping graphene superconductivity with nanometer precision
Graphene holds great potential for superconductivity due to its pure 2D
nature, the ability to tune its carrier density through electrostatic gating, and
its unique, relativistic-like electronic properties. At present, still far from
controlling and understanding graphene superconductivity, mainly because
the selective introduction of superconducting properties to graphene is
experimentally very challenging. Here, a method is developed that enables
shaping at will graphene superconductivity through a precise control of
graphene-superconductor junctions. The method combines the proximity
effect with scanning tunnelling microscope (STM) manipulation capabilities.
Pb nano-islands are first grown that locally induce superconductivity in
graphene. Using a STM, Pb nano-islands can be selectively displaced, over
different types of graphene surfaces, with nanometre scale precision, in any
direction, over distances of hundreds of nanometres. This opens an exciting
playground where a large number of predefined graphene-superconductor
hybrid structures can be investigated with atomic scale precision. To illustrate
the potential, a series of experiments are performed, rationalized by the
quasi-classical theory of superconductivity, going from the fundamental
understanding of superconductor-graphene-superconductor heterostructures
to the construction of superconductor nanocorrals, further used as “portable”
experimental probes of local magnetic moments in grapheneThe authors acknowledge funding from the Spanish Ministry of Science
and Innovation MCIN/AEI/10.13039/297 501100011033 though grants #
PID2020-115171GB-I00, PID2020-114880GB-I00, PID2019-107338RB-C61
and the “María de Maeztu” Programme for Units of Excellence in R&D
(CEX2018-000805-M, CEX2020-001038-M), the Comunidad de Madrid
NMAT2D-CM program under grant S2018/NMT-4511, the Comunidad de
Madrid, the Spanish State and the European Union by the Recovery, Transformation and Resilience Plan “Materiales Disruptivos Bidimensionales
(2D)” (MAD2D-CM)-UAM3 and the European Union through the Next
Generation EU funds and the Horizon 2020 FET-Open project SPRING
(No. 863098). J. C. C. thanks the German Science Foundation DFG and
SFB 1432 for sponsoring his stay at the University of Konstanz as a Mercator Fello
Biodegradation of lignocellulosics: microbial, chemical, and enzymatic aspects of the fungal attack of lignin
Wood is the main renewable material on Earth and is largely used as building material and in paper-pulp manufacturing. This review describes the composition of lignocellulosic materials, the different processes by which fungi are able to alter wood, including decay patterns caused by white, brown, and soft-rot fungi, and fungal staining of wood. The chemical, enzymatic, and molecular aspects of the fungal attack of lignin, which represents the key step in wood decay, are also discussed. Modern analytical techniques to investigate fungal degradation and modification of the lignin polymer are reviewed, as are the different oxidative enzymes (oxidoreductases) involved in lignin degradation. These include laccases, high redox potential ligninolytic peroxidases (lignin peroxidase, manganese peroxidase, and versatile peroxidase), and oxidases. Special emphasis is given to the reactions catalyzed, their synergistic action on lignin, and the structural bases for their unique catalytic properties. Broadening our knowledge of lignocellulose biodegradation processes should contribute to better control of wood-decaying fungi, as well as to the development of new biocatalysts of industrial interest based on these organisms and their enzymes. [Int Microbiol 2005; 8(3):195-204
New Insights on Structures Forming the Lignin-Like Fractions of Ancestral Plants
In the present work, lignin-like fractions were isolated from several ancestral plants –including moss (Hypnum cupressiforme and Polytrichum commune), lycophyte (Selaginella kraussiana), horsetail (Equisetum palustre), fern (Nephrolepis cordifolia and Pteridium aquilinum), cycad (Cycas revoluta), and gnetophyte (Ephedra fragilis) species– and structurally characterized by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Py-GC/MS yielded marker compounds characteristic of lignin units, except in the H. cupressiforme, P. commune and E. palustre “lignins, ” where they were practically absent. Additional structural information on the other five samples was obtained from 2D-NMR experiments displaying intense correlations signals of guaiacyl (G) units in the fern and cycad lignins, along with smaller amounts of p-hydroxyphenyl (H) units. Interestingly, the lignins from the lycophyte S. kraussiana and the gnetophyte E. fragilis were not only composed of G- and H-lignin units but they also incorporated significant amounts of the syringyl (S) units characteristic of angiosperms, which appeared much later in plant evolution, most probably due to convergent evolution. The latter finding is also supported by the abundance of syringol derivatives after the Py-GC/MS analyses of these two samples. Regarding lignin structure, β−O−4′ alkyl-aryl ethers were the most abundant substructures, followed by condensed β−5′ phenylcoumarans and β−β′ resinols (and dibenzodioxocins in the fern and cycad lignins). The highest percentages of alkyl-aryl ether structures correlated with the higher S/G ratio in the S. Kraussiana and E. fragilis lignin-like fractions. More interestingly, apart from the typical monolignol-derived lignin units (H, G and S), other structures, assigned to flavonoid compounds never reported before in natural lignins (such as amentoflavone, apigenin, hypnogenol B, kaempferol, and naringenin), could also be identified in the HSQC spectra of all the lignin-like fractions analyzed. With this purpose, in vitro synthesized coniferyl-naringenin and coniferyl-apigenin dehydrogenation polymers were used as standards. These flavonoids were abundant in H. cupressiforme appearing as the only constituents of the moss lignin-like fraction (including 84% of dimeric hypnogenol B) and their abundance decreased in those of S. Kraussiana (with amentoflavone and naringenin representing 14% of the total aromatic units), and the two ancient gymnosperms (0.4–1.2%) and ferns (0–0.7%)
Recessive dystrophic epidermolysis bullosa: the origin of the c.6527insC mutation in the Spanish population
This work was supported by grants from the Spanish
Ministry of Science and Innovation (MICINN) (SAF2007-61019 and
SAF 2010-16976), INTRA ⁄08 ⁄714.1 and INTRA ⁄09 ⁄758 from the
Biomedical Network Research Centre on Rare Diseases (CIBERER) and
S2010 ⁄BMD-2420 (CELLCAM) from Comunidad de Madrid
Feasibility of Double-Blind Clinical Trials with Oral Diacetylmorphine: A Randomized Controlled Phase II Study in an Inpatient Setting
The aim of this study was to evaluate the feasibility of conducting double-blind controlled randomized clinical trials using twice-a-day immediate-release oral diacetylmorphine (DAM) in heroin-dependent patients, by means of measuring the capacity of oral DAM to block opiate withdrawal and clinicians' ability to distinguish it from morphine and methadone. This was a randomized, phase II, double-blind, multicenter pilot study comparing immediate-release oral DAM, slow-release oral morphine and oral methadone administered twice a day during 10 days. Forty-five heroin-dependent patients were randomly assigned to these three treatment groups in an inpatient regime. Patients were stabilized with a mean of 350 mg (SD = 193) of immediate-release oral DAM, 108 mg (SD = 46.2) of slow-release oral morphine and 40 mg (SD = 17.9) of methadone. No statistically significant differences were found between any studied medication in clinical outcome. Neither patients nor clinicians were able to identify the administered medication. This study shows the feasibility of double-blind clinical trials using b.i.d. immediate-release oral DAM allowing further phase III clinical trials in the process of introducing oral DAM as a medication for heroin-dependent patients not responding to standard maintenance treatments
Peptide metal-organic frameworks under pressure: flexible linkers for cooperative compression
We investigate the structural response of a dense peptide metal-organic framework using in situ powder and single-crystal X-ray diffraction under high-pressures. Crystals of Zn(GlyTyr)2 show a reversible compression by 13% in volume at 4 GPa that is facilitated by the ability of the peptidic linker to act as a flexible string for a cooperative response of the structure to strain. This structural transformation is controlled by changes to the conformation of the peptide, which enables a bond rearrangement in the coordination sphere of the metal and changes to the strength and directionality of the supramolecular interactions specific to the side chain groups in the dipeptide sequence. Compared to other structural transformations in Zn(II) peptide MOFs, this behaviour is not affected by host/guest interactions and relies exclusively on the conformational flexibility of the peptide and its side chain chemistry
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