| 1. |
- Carraminana, Albert, et al.
(author)
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Rationale and Study Design for an Individualized Perioperative Open Lung Ventilatory Strategy in Patients on One-Lung Ventilation (iPROVE-OLV)
- 2019
-
In: Journal of Cardiothoracic and Vascular Anesthesia. - : W B SAUNDERS CO-ELSEVIER INC. - 1053-0770 .- 1532-8422. ; 33:9, s. 2492-2502
-
Journal article (peer-reviewed)abstract
- Objective: The aim of this clinical trial is to examine whether it is possible to reduce postoperative complications using an individualized perioperative ventilatory strategy versus using a standard lung-protective ventilation strategy in patients scheduled for thoracic surgery requiring one-lung ventilation. Design: International, multicenter, prospective, randomized controlled clinical trial. Setting: A network of university hospitals. Participants: The study comprises 1,380 patients scheduled for thoracic surgery. Interventions: The individualized group will receive intraoperative recruitment maneuvers followed by individualized positive end-expiratory pressure (open lung approach) during the intraoperative period plus postoperative ventilatory support with high-flow nasal cannula, whereas the control group will be managed with conventional lung-protective ventilation. Measurements and Main Results: Individual and total number of postoperative complications, including atelectasis, pneumothorax, pleural effusion, pneumonia, acute lung injury; unplanned readmission and reintubation; length of stay and death in the critical care unit and in the hospital will be analyzed for both groups. The authors hypothesize that the intraoperative application of an open lung approach followed by an individual indication of high-flow nasal cannula in the postoperative period will reduce pulmonary complications and length of hospital stay in high-risk surgical patients. (C) 2019 Published by Elsevier Inc.
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| 2. |
- Fontes-Candia, Cynthia, et al.
(author)
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Maximizing the oil content in polysaccharide-based emulsion gels for the development of tissue mimicking phantoms
- 2021
-
In: Carbohydrate Polymers. - : Elsevier Ltd. - 0144-8617 .- 1879-1344. ; 256
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Journal article (peer-reviewed)abstract
- Formulations based on agar and κ-carrageenan were investigated for the production of emulsion gels applicable as tissue mimicking phantoms. The effects of the polysaccharide matrix, the oil content and the presence of surfactants on the micro-/nanostructure, rheology, and mechanical and dielectric properties were investigated. Results showed a high capacity of the agar to stabilize oil droplets, producing gels with smaller (10−21 μm) and more uniform oil droplets. The addition of surfactants allowed increasing the oil content and reduced the gel strength and stiffness down to 57 % and 34 %, respectively. The permittivity and conductivity of the gels were reduced by increasing the oil content, especially in the agar gels (18.8 and 0.05 S/m, respectively), producing materials with dielectric properties similar to those of low-water content tissues. These results evidence the suitability of these polysaccharides to design a variety of tissue mimicking phantoms with a broad range of mechanical and dielectric properties.
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| 3. |
- Fontes-Candia, Cynthia, et al.
(author)
-
Rheological and structural characterization of carrageenan emulsion gels
- 2020
-
In: Algal Research. - : Elsevier B.V.. - 2211-9264. ; 47
-
Journal article (peer-reviewed)abstract
- Carrageenan emulsion gels containing sunflower oil were prepared using three different commercial carrageenan grades (κ-C, ι-C and λ-C). The effect of the carrageenan and salt content, as well as the oil:water ratio, on the emulsion gel strength was evaluated through a response surface methodology. Moreover, the rheological properties and the micro- and nanostructure from the stronger emulsion gel formulations were investigated and compared to their analogous hydrogel formulations. Interestingly, emulsion gels formed stronger and more thermally stable networks than the hydrogels, being this effect more evident in ι-C and λ-C. The results indicate that this was mainly due to a polysaccharide concentration effect, as no evidence of interactions between the carrageenan and the oil phase was found. Consequently, the rheological behaviour of the emulsion gels was mostly determined by the type of carrageenan. The association of carrageenan molecular chains was favoured in κ-C and λ-C (due to the presence of κ-carrageenan in the latter) and promoted by the addition of KCl. In contrast, a lower degree of chain association, mostly driven by ionic cross-linking, took place in ι-C. These results evidence the relevance of the gelation mechanism on the properties of emulsion gels and provide the basis for the design of these systems for targeted applications within the food industry.
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| 4. |
- Martinez-Sanz, Marta, et al.
(author)
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Advanced structural characterisation of agar-based hydrogels : Rheological and small angle scattering studies
- 2020
-
In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 236
-
Journal article (peer-reviewed)abstract
- Agar-based extracts from Gelidium sesquipedale were generated by heat and combined heat-sonication, with and without the application of alkali pre-treatment. Pre-treatment yielded extracts with greater agar contents; however, it produced partial degradation of the agar, reducing its molecular weight. Sonication produced extracts with lower agar contents and decreased molecular weights. A gelation mechanism is proposed based on the rheological and small angle scattering characterization of the extracts. The formation of strong hydrogels upon cooling was caused by the association of agarose chains into double helices and bundles, the sizes of which depended on the agar purity and molecular weight. These different arrangements at the molecular scale consequently affected the mechanical performance of the obtained hydrogels. Heating of the hydrogels produced a gradual disruption of the bundles; weaker or smaller bundles were formed upon subsequent cooling, suggesting that the process was not completely reversible.
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| 5. |
- Martínez-Sanz, Marta, et al.
(author)
-
Composition and rheological properties of microalgae suspensions : Impact of ultrasound processing
- 2020
-
In: Algal Research. - : Elsevier B.V.. - 2211-9264. ; 49
-
Journal article (peer-reviewed)abstract
- In this study the rheological properties of aqueous suspensions of three microalgae species, Nannochloropsis gaditana, Scenedesmus almeriensis and Spirulina platensis, were investigated as a function of solids content, and related to their composition and microstructure. In addition, the impact of ultrasound processing on their structuring ability was also studied. The less rigid character of the Spirulina platensis cell walls (with very low carbohydrate contents) and the presence of extracellular components promoted cell-cell interactions, yielding suspensions which showed a shear thinning behaviour at lower concentrations than Nannochloropsis gaditana and Scenedesmus almeriensis. It is noteworthy that the three species showed different viscoelastic properties at 25 wt.% total solids. Spirulina platensis suspensions showed a more elastic behaviour and lower frequency dependence, characteristic of weak gels, whilst Nannochloropsis gaditana and Scenedesmus almeriensis behaved more like viscous liquids. The ultrasound treatment did not affect the cell wall integrity, but it promoted the release of intracellular components (some of which could have been partially degraded) and disrupted physical interparticle interactions in Nannochloropsis gaditana and Scenedesmus almeriensis. This has an impact on the rheological properties, increasing the viscosity of Nannochloropsis gaditana suspensions, whilst the viscosity of Scenedesmus almeriensis suspensions was reduced. The outcomes of this work give insights into the exploitation of these microalgae species in soft materials for food, pharma and other technological applications.
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| 6. |
- Martínez-Sanz, Marta, et al.
(author)
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Nano-/microstructure of extruded Spirulina/starch foams in relation to their textural properties
- 2020
-
In: Food Hydrocolloids. - : Elsevier B.V.. - 0268-005X .- 1873-7137. ; 103
-
Journal article (peer-reviewed)abstract
- This work reports on an in-depth characterization of the nano- and microstructure of extruded starch foams loaded with the microalga Spirulina (1, 5 and 10 wt%), as well as the implications of Spirulina incorporation on the textural properties of the foams. Due to the gelatinization process occurring during extrusion, the crystalline and lamellar structures originally present in the starch granule were disrupted, resulting in very amorphous foams. Moreover, the crystalline structure of the fatty acids present in the raw microalga was lost during processing. The presence of Spirulina intracellular components induced the formation of more thermally-stable V-type crystallites through complexation with amylose, hence producing slightly more crystalline foams (XC~5–9%) than the pure extruded starch (XC ~3%). This affected the microstructure of the hybrid foams, which showed more densely packed and well-connected porous structures. Microstructural changes had an impact on the texture of the foams, which became harder with greater Spirulina loadings. The foams underwent very limited re-crystallization upon storage, which was further reduced by the presence of Spirulina. Interestingly, the free fatty acids from Spirulina re-crystallized and the resistant starch content in the 10% Spirulina foam increased, which could potentially be interesting from a nutritional perspective. These results show the potential of extrusion cooking to produce healthier snack foods and highlight the suitability of advanced characterization tools such as neutron tomography and small angle X-ray scattering to investigate food structure.
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| 7. |
- Bermejo-López, Aitor, et al.
(author)
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Selective Synthesis of Imines by Photo-Oxidative Amine Cross-Condensation Catalyzed by PCN-222(Pd)
- 2021
-
In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:43, s. 14405-14415
-
Journal article (peer-reviewed)abstract
- Palladium-metalated PCN-222 enables the aerobic photo-oxidative cross-condensation of anilines with benzylic amines yielding a series of linear and cyclic imines. The reaction is very efficient under mild conditions, which allows the isolation of simple, yet elusive, intermediates such as 2-(benzylideneamino)-aniline and 2-(benzylideneamino)phenols. Recyclability studies show excellent activity and selectivity after five runs. The methodology was successfully applied for the synthesis of an antitumor agent (PMX-610).
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| 8. |
- Bermejo-López, Aitor, et al.
(author)
-
Selective Synthesis of Imines via Photooxidative AmineCross-Condensation Catalyzed by PCN-222(Pd)
-
Other publication (other academic/artistic)abstract
- Palladium metallated PCN-222 enables the selective cross-condensation of anilines with benzylic aminesunder photooxidative conditions and at ambient temperature. The method affords a series of linear and cyclic Schiffbases. The mild conditions used in this catalytic system results in the isolation of resourceful intermediates such as 2-(benzylideneamino)aniline and 2-(benzylideneamino)phenols, which can be further modified.
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| 9. |
- Bojorges, Hylenne, et al.
(author)
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Structural and functional properties of alginate obtained by means of high hydrostatic pressure-assisted extraction
- 2023
-
In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 299
-
Journal article (peer-reviewed)abstract
- The effects of the high hydrostatic pressure (HPP) pre-treatment on the alginate extraction were seen to greatly depend on the recalcitrant nature of two algae species. Alginates were deeply characterized in terms of composition, structure (HPAEC-PAD, FTIR, NMR, SEC-MALS), functional and technological properties.The pre-treatment significantly increased the alginate yield in the less recalcitrant A. nodosum (AHP) also favoring the extraction of sulphated fucoidan/fucan structures and polyphenols. Although the molecular weight was significantly lower in AHP samples, neither the M/G ratio nor the M and G sequences were modified. In contrast, a lower increase in alginate extraction yield was observed for the more recalcitrant S. latissima after the HPP pre-treatment (SHP), but it significantly affected the M/G values of the resulting extract. The gelling properties of the alginate extracts were also explored by external gelation in CaCl2 solutions. The mechanical strength and nanostructure of the hydrogel beads prepared were determined using compression tests, synchro-tron small angle X-ray scattering (SAXS), and cryo-scanning electron microscopy (Cryo-SEM). Interestingly, the application of HPP significantly improved the gel strength of SHP, in agreement with the lower M/G values and the stiffer rod-like conformation obtained for these samples.
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| 10. |
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| 11. |
- Fernández, Amparo, et al.
(author)
-
¿Vamos a dejar que prohíban la expresión de algunes?
- 2022
-
Other publication (pop. science, debate, etc.)abstract
- Siguiendo el ejemplo de Ope Pasquet en 2020, que ya comentamos en la diaria,1 la diputada Inés Monzillo presentó en marzo de este año un proyecto de ley para implementar medidas de política lingüística en Uruguay con el título “Alteraciones gramaticales y fonéticas. Prohibición de su uso dentro de la Administración Pública e Instituciones de Enseñanza públicas y privadas”. Monzillo quiere prohibir o censurar el lenguaje inclusivo, y plantea una visión extremadamente reducida del debate sobre el tema en las lenguas románicas.
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| 12. |
- Fernandez-Benito, Amparo, et al.
(author)
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Green and Scalable Biopolymer-Based Aqueous Polyelectrolyte Complexes for Zinc-Ion Charge Storage Devices
- 2023
-
In: ChemElectroChem. - : WILEY-V C H VERLAG GMBH. - 2196-0216. ; 10:2
-
Journal article (peer-reviewed)abstract
- Green and scalable materials are essential to fulfill the need of electrification for transitioning into a fossil-fuels free society, and sustainability is a requirement for all new technologies. Rechargeable batteries are one of the most important elements for electrification, enabling the transition to mobile electronics, electrical vehicles and grid storage. We here report synthesis and characterization of polyelectrolyte complexes of alginate and chitosan, both biopolymers deriving from the sea, for transport of zinc ions in hydrogel electrolytes. We have used vibrational spectroscopy, thermal measurements and microscopy, as well as transport measurements with ohmic or blocking contacts. The transference number for zinc ions is close to 1, the conductivity is approximate to 10 mS/cm, with stability at Zn interfaces seen through 7000 cycles in symmetric zinc//zinc cell. A zinc ion aqueous electrolyte was prepared from blends of chitosan and alginate, by using a simple and scalable route. These green zinc ion electrolytes exhibit a stability window up to 2 V, a zinc ion transference number close to 1, and electrochemical cyclability over 7000 cycles at interfaces to zinc. This biologically derived polyelectrolyte complex offers many possibilities for optimizing transport and stability at electrode interfaces.image
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| 13. |
- Fontes-Candia, Cynthia, et al.
(author)
-
Understanding nanostructural differences in hydrogels from commercial carrageenans: Combined small angle X-ray scattering and rheological studies
- 2020
-
In: Algal Research. - : Elsevier BV. - 2211-9264. ; 47, s. 101882-
-
Journal article (peer-reviewed)abstract
- Hydrogels from commercial carrageenans (κ-C, ι-C, λ↑-C (high viscosity) and λ↓-C (low viscosity)) were prepared with and without the addition of salts (KCl and CaCl2). FT-IR and 1H NMR characterization evidenced that while the κ-C and ι-C grades were relatively pure carrageenans, the two λ-C grades were λ-, κ-, θ- and μ-carrageenan hybrids. The effect of carrageenan and salt concentration on the hydrogel strength were evaluated through a response surface design and a detailed structural characterization was carried out by small angle X-ray scattering (SAXS) and rheology. The low amount of sulphate substitution in κ-C enabled intramolecular association, giving rise to strong hydrogels, even in the absence of salts. On the other hand, ι-C, λ↑-C and λ↓-C produced much weaker hydrogels and required the addition of salts to induce intramolecular association by ionic cross-linking. SAXS results suggested the formation of similar structures of double helices in κ-C and ι-C with the addition of salts; however, distinct network structures were attained. In the case of κ-C, a Gauss-Lorentz gel model was suitable to describe the hydrogel structure and the addition of K+ promoted the formation of more ordered and densely packed structures. On the other hand, larger but weaker aggregates, with marked periodicity, were observed in ι-C, with Ca2+ inducing the formation of more densely packed networks. The complex composition of the λ-C grades gave rise to more heterogeneous branched network structures, properly described by a correlation length model, where the gelation mechanism was mostly governed by the κ-carrageenan component.
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| 14. |
- Granero, Roser, et al.
(author)
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Phenotype of Gambling Disorder Patients with Lotteries as a Preferred Form of Gambling
- 2023
-
In: International Journal of Mental Health and Addiction. - : Springer Science and Business Media LLC. - 1557-1874 .- 1557-1882. ; 21, s. 3306-3329
-
Journal article (peer-reviewed)abstract
- Lottery gambling can become an addictive behavior which can significantly interfere with daily functioning. The objectives of this work were to estimate the prevalence of lottery gambling, to assess the profile related to this gambling type in a large clinical sample of patients who met criteria for gambling disorder (GD), and to compare this profile with the other two non-strategic forms of gambling (slot-machines and bingo). Sample included n = 3,531 patients consecutively attended for treatment-seeking due to gambling-related problems. All the participants met criteria for GD and were into the range of 18 to 85 years old. Sociodemographic variables, GD severity, psychopathological state, and personality traits were assessed. Statistical comparisons between the groups defined by the patients’ gambling preference (lotteries versus other gambling activities) were conducted, with chi-square test and analysis of variance. The prevalence of lotteries as the only gambling activity was 2.5%, 8.9% for lottery gambling as primary activity with other secondary gambling types, and 20.6% for lotteries as primary or secondary gambling activity. Lottery gambling and bingo gambling were more prevalent among women (bingo included the highest percentage of women). Compared to slot machine gambling, lotteries and bingo grouped older patients and those with later age of onset of the gambling-related problems. Bingo gambling showed the highest psychological distress and the most dysfunctional personality traits. This study shows the high frequency of lottery gambling among treatment-seeking for GD patients, and it provides empirical evidence about the profile associated with this gambling activity compared to other non-strategic gambling forms. The likelihood of lottery gambling is higher for women, patients married or living with a stable partner, and those within higher social position indexes.
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| 15. |
- López-Rubio, Amparo, et al.
(author)
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Strategies to Improve the Properties of Amaranth Protein Isolate-Based Thin Films for Food Packaging Applications : Nano-Layering through Spin-Coating and Incorporation of Cellulose Nanocrystals
- 2020
-
In: Nanomaterials. - : MDPI. - 2079-4991. ; 10:12
-
Journal article (peer-reviewed)abstract
- In this work, two different strategies for the development of amaranth protein isolate (API)-based films were evaluated. In the first strategy, ultrathin films were produced through spin-coating nanolayering, and the effects of protein concentration in the spin coating solution, rotational speed, and number of layers deposited on the properties of the films were evaluated. In the second strategy, cellulose nanocrystals (CNCs) were incorporated through a casting methodology. The morphology, optical properties, and moisture affinity of the films (water contact angle, solubility, water content) were characterized. Both strategies resulted in homogeneous films with good optical properties, decreased hydrophilic character (as deduced from the contact angle measurements and solubility), and improved mechanical properties when compared with the neat API-films. However, both the processing method and film thickness influenced the final properties of the films, being the ones processed through spin coating more transparent, less hydrophilic, and less water-soluble. Incorporation of CNCs above 10% increased hydrophobicity, decreasing the water solubility of the API films and significantly enhancing material toughness.
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| 16. |
- Martínez-Pérez, Amparo, et al.
(author)
-
Changes in the Immune Phenotype and Gene Expression Profile Driven by a Novel Tuberculosis Nanovaccine : Short and Long-Term Post-immunization
- 2021
-
In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 11
-
Journal article (peer-reviewed)abstract
- Deciphering protection mechanisms against Mycobacterium tuberculosis (Mtb) remains a critical challenge for the development of new vaccines and therapies. We analyze the phenotypic and transcriptomic profile in lung of a novel tuberculosis (TB) nanoparticle-based boosting mucosal vaccine Nano-FP1, which combined to BCG priming conferred enhanced protection in mice challenged with low-dose Mtb. We analyzed the vaccine profile and efficacy at short (2 weeks), medium (7 weeks) and long term (11 weeks) post-vaccination, and compared it to ineffective Nano-FP2 vaccine. We observed several changes in the mouse lung environment by both nanovaccines, which are lost shortly after boosting. Additional boosting at long-term (14 weeks) recovered partially cell populations and transcriptomic profile, but not enough to enhance protection to infection. An increase in both total and resident memory CD4 and CD8 T cells, but no pro-inflammatory cytokine levels, were correlated with better protection. A unique gene expression pattern with differentially expressed genes revealed potential pathways associated to the immune defense against Mtb. Our findings provide an insight into the critical immune responses that need to be considered when assessing the effectiveness of a novel TB vaccine.
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| 17. |
- Martínez-Sanz, Marta, et al.
(author)
-
Alternative protocols for the production of more sustainable agar-based extracts from Gelidium sesquipedale
- 2021
-
In: Algal Research. - : Elsevier B.V.. - 2211-9264. ; 55
-
Journal article (peer-reviewed)abstract
- Agar-based extracts from Gelidium sesquipedale were obtained by applying a conventional hot water treatment and alternative ultrasound- and microwave-assisted methods, with and without the application of an alkaline pre-treatment. The alkaline pre-treatment produced refined extracts with higher purity; however, extraction yields increased from 2–5% to 7–19% by omitting this step. In particular, the ultrasound-assisted extraction allowed reducing 4-fold the extraction time, while keeping constant or even increasing the yield (up to 19% for the 1 h extraction) with respect to the conventional protocol. Interestingly, the presence of proteins and polyphenols conferred the semi-refined extracts a relatively high antioxidant capacity (19–24 μmol TE/g extract). The refined extract produced by the standard protocol formed the strongest hydrogels (>1000 g/cm2). On the other hand, the semi-refined extracts produced by the alternative protocols formed slightly stronger hydrogels (337–438 g/cm2) than the refined counterparts (224–311 g/cm2), due to their greater molecular weights of the former ones. LCA assessment showed lower global warming potential for the semi-refined extracts, especially the ultrasound-assisted extraction, hence highlighting the potential of this method to produce more sustainable agar-based extracts for food-related applications.
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| 18. |
- Martinez-Sanz, Marta, et al.
(author)
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Development of bacterial cellulose nanowhiskers reinforced EVOH composites by electrospinning
- 2012
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In: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 124:2, s. 1398-1408
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Journal article (peer-reviewed)abstract
- In the current study, hybrid electrospun ethylene vinyl alcohol (EVOH) fibers reinforced with bacterial cellulose nanowhiskers (BCNW) were developed and characterized. Additionally, electrospinning was suggested as a method for the incorporation of well-dispersed BCNW into an EVOH matrix by melt compounding. With the aim of maximizing the BCNW's loading in the electrospun fibers, an optimized method was applied for generating fibers from solutions containing up to 40 wt % BCNW. As demonstrated by FTIR spectroscopy, it was possible to incorporate BCNW concentrations up to similar to 24 wt %, although a complete incorporation of the nanofiller into the fibers was only achieved with solutions containing up to 20 wt % of the filler, DSC analyses suggested that the incorporation of the nanofiller reduced the crystallinity of the as-obtained EVOH fibers and produced an increase in the glass transition temperature of these during the second heating run. Thermogravimetric analyses showed that even though EVOH protects the nanowhiskers from thermal degradation, the electrospun hybrid fibers present a relatively lower thermal stability than the pure EVOH fibers. FTIR analyses of the samples subjected to different thermal treatments confirmed that the stiffening effect observed by DSC only occurs after melting of the EVOH phase and is cooperative with a partial acid chemical development in the BCNW, which promotes strong chemical interactions between the polymeric matrix and the nanofiller. Finally, the hybrid electrospun fibers were incorporated into pure EVOH by melt compounding to produce composite films. This methodology showed higher stability and dispersion of the BCNW than direct addition of the freeze-dried nanofiller to EVOH.
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| 19. |
- Martinez-Sanz, Marta, et al.
(author)
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Development of electrospun EVOH fibres reinforced with bacterial cellulose nanowhiskers. Part I : Characterization and method optimization
- 2011
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In: Cellulose. - DORDRECHT : SPRINGER. - 0969-0239 .- 1572-882X. ; 18:2, s. 335-347
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Journal article (peer-reviewed)abstract
- In the present study, hybrid electrospun EVOH fibres reinforced with bacterial cellulose nanowhiskers (BCNW) were developed and characterized. The nanowhiskers, obtained by sulphuric acid digestion of native bacterial cellulose mats generated by Gluconacetobacter xylinum, were morphologically characterized by SEM and optical microscopy with polarized light and revealed a highly crystalline structure of nanofibrils aggregates. XRD analyses suggested a crystalline structure corresponding to the cellulose I allomorph. It was also confirmed by means of FT-IR spectroscopy that amorphous regions were preferentially digested by the acid treatment, whereas TGA analyses showed a decrease in the thermal stability of the nanowhiskers most likely due to incorporation of sulphate groups and the inherent acidity remaining in the filler even after extensive washing cycles. A method was developed for improving the incorporation of BCNW within the EVOH electrospun fibres, consisting on the addition of the BCNW in the form of a centrifuged precipitate, versus the most conventionally employed freeze-dried nanowhiskers. DSC analyses showed a significant increase in the glass transition temperature of the composites during the second heating run, which may be related to the acidic character of the nanofiller. Finally, sonication was seen to enhance interfacial interaction but to reduce the incorporation of the filler in the matrix in the case of the centrifuged material.
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| 20. |
- Morandeira, Ana, et al.
(author)
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Ru(II)-phthalocyanine sensitized solar cells : the influence of co-adsorbents upon interfacial electron transfer kinetics
- 2009
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In: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 19:28, s. 5016-5026
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Journal article (peer-reviewed)abstract
- The development of efficient red sensitizer dyes is essential for the optimization of dye-sensitized photoelectrochemical solar cells. Ru-phthalocyanines are good candidates because they show high absorbance in the red while their axial ligands hinder the formation of aggregates, a recurrent problem among phthalocyanine dyes. In this paper, we present the photophysics and photovoltaic device performance for a series of novel Ru-phthalocyanines. We focus in particular upon the origin of the enhancement in device performance observed in the presence of two additives, Li+ and chenodeoxycholic acid. The addition of Li+ lowers the conduction band edge of the TiO2 semiconductor leading to a higher electron injection yield and a higher photocurrent in the device. The increases in injection yield and photocurrent are large for these sensitizers, compared to the widely studied ruthenium bipyridyl dye N719, due to the relatively slow injection dynamics, emphasizing the importance of injection yield in limiting device performance for this Ru-phthalocyanine dye series. Of particular interest is the effect of chenodeoxycholic acid. This coadsorbent dramatically enhances the photocurrent of the studied devices without lowering the photovoltage. Unlike previous studies, in this case the photocurrent rise can not be attributed to an increment in the electron injection yield due to the effect of the coadsorbent hindering the formation of dye aggregates. Photophysical measurements instead show that the slower recombination of dye cations with the TiO2, electrons and faster regeneration of the dye cations by the electrolyte are the reasons for the enhanced photocurrent.
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| 21. |
- Olsson, Richard T., et al.
(author)
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Extraction of Microfibrils from Bacterial Cellulose Networks for Electrospinning of Anisotropic Biohybrid Fiber Yarns
- 2010
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In: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 43:9, s. 4201-4209
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Journal article (peer-reviewed)abstract
- Electrospinning of uniform biohybrid fibers with concealed cellulose microfibrils (CMF) is reported as a promising and environmentally sound concept for reinforcement of polymer nonwoven fiber systems of fine dimensions. The extraction and refinement of the high-strength crystalline microfibril bundles (15-20 nm thick) from bacterial cellulose networks is presented, as well as their morphology prior to and post electrospinning. Nanofibers composed of a poly(methyl methacrylate) (PMMA) matrix with cellulose contents reaching 20 wt % were repeatedly obtained. A high deuce of dispersion of the microfibrils was obtained for a variety of CMF contents and the aggregation of the CMF was greatly suppressed as the microfibrils were aligned and rapidly sealed inside the acrylate matrix during the continuous formation of the fibers. The limited CMF aggregation up to 7 wt % was related to a suppressed phase separation caused by the rapid solidification of the polymer solutions during spinning. The fibers' diameters decreased significantly from similar to 1.8 mu m (1 wt %) to similar to 100 nm (20 wt %) with increasing cellulose contents, resulting in CMF agglomerations and percolating architectures within the acrylate host, which was consistent with microscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) evaluations. The nominal content of cellulose in the fibers was assessed by Lorentzian profile fit assignment of the crystalline vs amorphous fractions of the fibers' X-ray diffractograms. TGA of fibers with low CMF content revealed that both CMF and PMMA showed a significantly improved thermal stability in the composite material. The biohybrid fibers were continuously aligned into an anisotropic nanocomposite yarns from a liquid support during spinning. The strategy described herein may allow for new mechanically robust nonwoven fiber systems, or be used as implemented on existing electrospun formulations that are lacking mechanical integrity. It is envisioned that the cellulose microfibrils may be of importance in biomedical applications where biocompatibility is a requirement.
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| 22. |
- Richards, Stephen, et al.
(author)
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Genome Sequence of the Pea Aphid Acyrthosiphon pisum
- 2010
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In: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:2, s. e1000313-
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Journal article (peer-reviewed)abstract
- Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
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| 23. |
- Romero-Picó, Amparo, et al.
(author)
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Hypothalamic κ-Opioid Receptor Modulates the Orexigenic Effect of Ghrelin.
- 2013
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In: Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 1740-634X. ; 38:7, s. 1296-307
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Journal article (peer-reviewed)abstract
- The opioid system is well recognized as an important regulator of appetite and energy balance. We now hypothesized that the hypothalamic opioid system might modulate the orexigenic effect of ghrelin. Using pharmacological and gene silencing approaches, we demonstrate that ghrelin utilizes a hypothalamic κ-opioid receptor (KOR) pathway to increase food intake in rats. Pharmacological blockade of KOR decreases the acute orexigenic effect of ghrelin. Inhibition of KOR expression in the hypothalamic arcuate nucleus is sufficient to blunt ghrelin-induced food intake. By contrast, the specific inhibition of KOR expression in the ventral tegmental area does not affect central ghrelin-induced feeding. This new pathway is independent of ghrelin-induced AMP-activated protein kinase activation, but modulates the levels of the transcription factors and orexigenic neuropeptides triggered by ghrelin to finally stimulate feeding. Our novel data implicate hypothalamic KOR signaling in the orexigenic action of ghrelin.
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| 24. |
- Rudovica, Vita, et al.
(author)
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Valorization of Marine Waste : Use of Industrial By-Products and Beach Wrack Towards the Production of High Added-Value Products
- 2021
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In: Frontiers in Marine Science. - : Frontiers Media S.A.. - 2296-7745. ; 8
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Research review (peer-reviewed)abstract
- Biomass is defined as organic matter from living organisms represented in all kingdoms. It is recognized to be an excellent source of proteins, polysaccharides and lipids and, as such, embodies a tailored feedstock for new products and processes to apply in green industries. The industrial processes focused on the valorization of terrestrial biomass are well established, but marine sources still represent an untapped resource. Oceans and seas occupy over 70% of the Earth's surface and are used intensively in worldwide economies through the fishery industry, as logistical routes, for mining ores and exploitation of fossil fuels, among others. All these activities produce waste. The other source of unused biomass derives from the beach wrack or washed-ashore organic material, especially in highly eutrophicated marine ecosystems. The development of high-added-value products from these side streams has been given priority in recent years due to the detection of a broad range of biopolymers, multiple nutrients and functional compounds that could find applications for human consumption or use in livestock/pet food, pharmaceutical and other industries. This review comprises a broad thematic approach in marine waste valorization, addressing the main achievements in marine biotechnology for advancing the circular economy, ranging from bioremediation applications for pollution treatment to energy and valorization for biomedical applications. It also includes a broad overview of the valorization of side streams in three selected case study areas: Norway, Scotland, and the Baltic Sea.
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| 25. |
- Yilmaz Turan, Secil, et al.
(author)
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Enzymatic production of hydrogels from corn bran feruloylated arabinoxylan with protective effects against reactive oxygen species
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Other publication (other academic/artistic)abstract
- The feruloylated nature of cereal bran arabinoxylans (AX) enables the production of strong hydrogen networks to be used as matrices for food and biomedical applications with protective effects against reactive oxygen species. Here we comparatively examine the physicochemical properties and radical scavenging activity of hydrogels developed from corn bran AX with high ferulic acid content following enzymatic crosslinking by laccase and peroxidase. Both enzymatic systems resulted in strong hydrogels with distinct kinetics, properties and ultrastructure. Peroxidase-mediated crosslinking exhibited much faster kinetics during hydrogel formation, whereas laccase-crosslinking provided a stronger network. Structural characterization by size exclusion chromatography, small angle X-ray scattering, and microscopy revealed that laccase formed aggregates with higher clustering strength, while peroxidase led to the occurrence of larger covalent polymer aggregates. As a proof of concept, we demonstrated that the AXhydrogels had adequate biocompatibility and demonstrated protective effects against oxidative stress on colon cells under in vitro conditions. The peroxidase-crosslinked hydrogel achieved a higher antioxidative effect. This study demonstrates the distinct effect of enzymatic crosslinking routes of highly feruloylated AX, resulting in hydrogels with tailored morphological, structural and rheological properties. Moreover, the AX hydrogels display excellent radical scavenging activity against cellular oxidative stress, which constitutes a proof of concept for their potential application in cell delivery, encapsulation and bio-fabrication.
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| 26. |
- Yilmaz Turan, Secil, et al.
(author)
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Hydrogels with protective effects against cellular oxidative stress via enzymatic crosslinking of feruloylated arabinoxylan from corn fibre
- 2022
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In: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 24:23, s. 9114-9127
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Journal article (peer-reviewed)abstract
- Biocatalytical upgrading of side streams from agricultural biomass into multifunctional materials constitutes a very attractive option to increase the circularity of food and material systems. We propose the design of radical scavenging hydrogels with mechanical integrity and protective effects against reactive oxygen species by enzymatic crosslinking of arabinoxylans (AX) with high ferulic acid content extracted from corn fibre using subcritical water. We have compared the influence of two enzymatic systems, laccase/O-2 and peroxidase/H2O2, on the biochemical structure, multiscale assembly, physicochemical properties, and radical scavenging activity of the polysaccharide hydrogels. Peroxidase crosslinking results in instant hydrogel formation, whereas laccase shows slower crosslinking kinetics, resulting in a more elastic gel network. Characterization by size exclusion chromatography, small angle X-ray scattering, and microscopy revealed structural differences in the network organization of the hydrogels produced by the two enzymes. Laccase crosslinking leads to smaller polymeric aggregates, promoting their progressive organization in network clusters that impact the overall ultrastructure. Conversely, the fast crosslinking induced by peroxidase results in higher porosity and forms larger and potentially more heterogeneous aggregates, which seem to hinder their subsequent association in clusters. Both AX hydrogels exhibit adequate biocompatibility and protective effects against in vitro cellular oxidative stress compared to an alginate reference. This constitutes a proof of concept of the potential application of radical scavenging hydrogels from agricultural side streams for biomedical and nutritional applications in wound healing, cellular repair and targeted delivery.
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| 27. |
- Yilmaz Turan, Secil, 1986-, et al.
(author)
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Revealing the mechanisms of hydrogel formation by laccase crosslinking and regeneration of feruloylated arabinoxylan from wheat bran
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Other publication (other academic/artistic)abstract
- Feruloylated arabinoxylan (FAX) from cereal brans has large potential to generate multifunctional materials with customized macromolecular and nanostructural architectures and techno-functional properties. Here we investigate the biochemical and structural mechanisms of hydrogel formation of wheat bran FAX following enzymatic crosslinking by laccase and a subsequent regeneration procedure involving freeze-drying and resuspension of the crosslinkedFAX in different pH buffers, using a battery of biochemical, rheological and biophysical techniques. The laccase crosslinking induced the conversion of ferulic acid units into a wide diversity of dimeric forms, leading to an increased molecular weight and a closer-packing of the FAX chains. The regeneration step resulted in a remarkable increase in the viscosity and viscoelasticity for all tested pH, especially under acidic conditions. The amount of crystallinity ofFAX increased by enzymatic crosslinking, it was however not influenced by the regeneration step. The structural characterization revealed that enzymatic crosslinking, in addition to the formation of covalent crosslinks, increases the physical intermolecular interactions between adjacent FAXdomains, and the regeneration forms larger clusters with higher dynamic moduli. Our results reveal that both chemical and physical mechanisms influence the network formation and multiscale assembly of wheat bran FAX hydrogels, thus modulating their rheological properties fundamental for their use in food and biomedical applications.
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| 28. |
- Yilmaz Turan, Secil, et al.
(author)
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Revealing the mechanisms of hydrogel formation by laccase crosslinking and regeneration of feruloylated arabinoxylan from wheat bran
- 2022
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In: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 128
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Journal article (peer-reviewed)abstract
- Feruloylated arabinoxylan (FAX) from cereal brans has large potential to generate multifunctional materials with customized macromolecular and nanostructural architectures and techno-functional properties. Here we investigate the chemical and structural mechanisms of hydrogel formation of wheat bran FAX following enzymatic crosslinking by laccase and a subsequent regeneration procedure involving freeze-drying and resuspension of the crosslinked FAX in different pH buffers, using a battery of biochemical, rheological and physical techniques. The laccase crosslinking induced the conversion of ferulic acid units into a wide diversity of dimeric forms, leading to an increased molecular weight and a closer-packing of the FAX chains. The regeneration step resulted in a remarkable increase in the viscosity and viscoelasticity for all tested pH values. The amount of crystallinity of FAX increased by enzymatic crosslinking, it was however decreased by the regeneration step. The structural characterization revealed that enzymatic crosslinking, in addition to the formation of covalent crosslinks, influences the physical intermolecular interactions between adjacent FAX domains, and the regeneration forms larger clusters with higher dynamic moduli. Our results reveal that both chemical and physical mechanisms influence the network formation and multiscale assembly of wheat bran FAX hydrogels, thus modulating their rheological properties fundamental for their use in food and biomedical applications.
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