1. |
- Santoro, V., et al.
(author)
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HighNESS conceptual design report: Volume I
- 2024
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In: Journal of Neutron Research. - 1023-8166 .- 1477-2655. ; 25:3-4, s. 85-314
-
Journal article (peer-reviewed)abstract
- The European Spallation Source, currently under construction in Lund, Sweden, is a multidisciplinary international laboratory. Once completed to full specifications, it will operate the world’s most powerful pulsed neutron source. Supported by a 3 million Euro Research and Innovation Action within the EU Horizon 2020 program, a design study (HighNESS) has been completed to develop a second neutron source located below the spallation target. Compared to the first source, designed for high cold and thermal brightness, the new source has been optimized to deliver higher intensity, and a shift to longer wavelengths in the spectral regions of cold (CN, 2–20 Å), very cold (VCN, 10–120 Å), and ultracold (UCN, >500 Å) neutrons. The second source comprises a large liquid deuterium moderator designed to produce CN and support secondary VCN and UCN sources. Various options have been explored in the proposed designs, aiming for world-leading performance in neutronics. These designs will enable the development of several new instrument concepts and facilitate the implementation of a high-sensitivity neutron-antineutron oscillation experiment (NNBAR). This document serves as the Conceptual Design Report for the HighNESS project, representing its final deliverable.
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2. |
- Santoro, V., et al.
(author)
-
HighNESS conceptual design report: Volume II. the NNBAR experiment.
- 2024
-
In: Journal of Neutron Research. - 1023-8166 .- 1477-2655. ; 25:3-4, s. 315-406
-
Journal article (peer-reviewed)abstract
- A key aim of the HighNESS project for the European Spallation Source is to enable cutting-edge particle physics experiments. This volume presents a conceptual design report for the NNBAR experiment. NNBAR would exploit a new cold lower moderator to make the first search in over thirty years for free neutrons converting to anti-neutrons. The observation of such a baryon-number-violating signature would be of fundamental significance and tackle open questions in modern physics, including the origin of the matter-antimatter asymmetry. This report shows the design of the beamline, supermirror focusing system, magnetic and radiation shielding, and anti-neutron detector necessary for the experiment. A range of simulation programs are employed to quantify the performance of the experiment and show how background can be suppressed. For a search with full background suppression, a sensitivity improvement of three orders of magnitude is expected, as compared with the previous search. Civil engineering studies for the NNBAR beamline are also shown, as is a costing model for the experiment.
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3. |
- Plivelic, Tomas S., et al.
(author)
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Concentrated protein solutions investigated using acoustic levitation and small-Angle X-ray scattering
- 2020
-
In: Journal of Synchrotron Radiation. - : International Union of Crystallography. - 0909-0495 .- 1600-5775. ; 27, s. 396-404
-
Journal article (peer-reviewed)abstract
- An acoustically levitated droplet has been used to collect synchrotron SAXS data on human serum albumin protein solutions up to a protein concentration of 400mgml-1. A careful selection of experiments allows for fast data collection of a large amount of data, spanning a protein concentration/solvent concentration space with limited sample consumption (down to 3μL per experiment) and few measurements. The data analysis shows data of high quality that are reproducible and comparable with data from standard flow-Through capillary-based experiments. Furthermore, using this methodology, it is possible to achieve concentrations that would not be accessible by conventional cells. The protein concentration and ionic strength parameter space diagram may be covered easily and the amount of protein sample is significantly reduced (by a factor of 100 in this work). Used in routine measurements, the benefits in terms of protein cost and time spent are very significant.
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4. |
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5. |
- Kuktaite, Ramune, et al.
(author)
-
Monitoring Nanostructure Dynamics and Polymerization in Glycerol Plasticized Wheat Gliadin and Glutenin Films : Relation to Mechanical Properties
- 2016
-
In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:6, s. 2998-3007
-
Journal article (peer-reviewed)abstract
- Gliadin and glutenin proteins with 10, 20, 30 and 40% of glycerol were compression molded into films (130 °C) and evaluated for protein polymerization, β-sheet structure and nano-structural morphology. Here, for the first time we show how different amounts of glycerol impact the nano-structure and functional properties of the gliadin and glutenin films. Most polymerized protein was found in the gliadin films with 20 and 30% glycerol, and in all the glutenin films (except 10%), by RP-HPLC. A β-sheet-rich protein structure was found to be high in the 10 and 20% glycerol gliadin films, and in the 20 and 30% glycerol glutenin films by FT-IR. Glycerol content of 20, 30 and 40% impacted the nano-structural morphology of the gliadin glycerol films observed by SAXS, and to a limited extent for 10 and 20% glycerol gliadin films revealed by WAXS. No ordered nano-structure was found for the glutenin glycerol films. The 20%, 30% and 40% glycerol films were the most tunable for specific mechanical properties. For the highest stiffness and strength, the 10% glycerol protein films were the best choice.
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6. |
- Muneer, Faraz, et al.
(author)
-
Impact of pH Modification on Protein Polymerization and Structure-Function Relationships in Potato Protein and Wheat Gluten Composites
- 2019
-
In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:1
-
Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and potato protein (PP) were modified to a basic pH by NaOH to impact macromolecular and structural properties. Films were processed by compression molding (at 130 and 150 degrees C) of WG, PP, their chemically modified versions (MWG, MPP) and of their blends in different ratios to study the impact of chemical modification on structure, processing and tensile properties. The modification changed the molecular and secondary structure of both protein powders, through unfolding and re-polymerization, resulting in less cross-linked proteins. The beta-sheet formation due to NaOH modification increased for WG and decreased for PP. Processing resulted in cross-linking of the proteins, shown by a decrease in extractability; to a higher degree for WG than for PP, despite higher beta-sheet content in PP. Compression molding of MPP resulted in an increase in protein cross-linking and improved maximum stress and extensibility as compared to PP at 130 degrees C. The highest degree of cross-linking with improved maximum stress and extensibility was found for WG/MPP blends compared to WG/PP and MWG/MPP at 130 degrees C. To conclude, chemical modification of PP changed the protein structures produced under harsh industrial conditions and made the protein more reactive and attractive for use in bio-based materials processing, no such positive gains were seen for WG.
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7. |
- Muneer, Faraz, et al.
(author)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
-
In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
-
Journal article (peer-reviewed)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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8. |
- Muneer, Faraz, et al.
(author)
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The impact of newly produced protein and dietary fiber rich fractions of yellow pea (Pisum sativum L.) on the structure and mechanical properties of pasta-like sheets
- 2018
-
In: Food Research International. - : Elsevier. - 0963-9969 .- 1873-7145. ; 106, s. 607-618
-
Journal article (peer-reviewed)abstract
- Two fractions from pea (Pisum sativum L.), protein isolate (PPI) and dietary fiber (PF), were newly produced by extraction-fractionation method and characterized in terms of particle size distribution and structural morphology using SEM. The newly produced PPI and PF fractions were processed into pasta-like sheets with varying protein to fiber ratios (100/0, 90/10, 80/20, 70/30 and 50/50, respectively) using high temperature compression molding. We studied protein polymerization, molecular structure and protein-fiber interactions, as well as mechanical performance and cooking characteristics of processed PPI-PF blends. Bi-modal particle size distribution and chemical composition of the PPI and PF fractions influenced significantly the physicochemical properties of the pasta-like sheets. Polymerization was most pronounced for the 100 PPI, 90/10 and 80/20 PPI-PF samples as studied by SE-HPLC, and polymerization decreased with addition of the PF fraction. The mechanical properties, as strength and extensibility, were likewise the highest for the 100 PPI and 90/10 PPI-PF blends, while the E-modulus was similar for all the studied blends (around 38 MPa). The extensibility decreased with the increasing amount of PF in the blend. The highest amounts of beta-sheets were found in the pasta-like sheets with high amounts of PPI (100, 90 and 80%), by FT-IR. An increase in PF fraction in the blend, resulted into the high amounts of unordered structures as observed by FT-IR, as well as in an increase in the molecular scattering distances observed by SAXS. The water uptake increased and cooking loss decreased with increased proportions of the PF fraction, and the consistency of 10 min cooked pasta-like sheets were alike al dente texture. The new knowledge obtained in this study on the use of extraction-fractionation method to produce novel PPI and PF fractions for developing innovative high nutritious food can be of a great importance. The obtained knowledge on the pea protein and fiber processing behaviour could greatly contribute to a better control of functional properties of various temperature-processed products from yellow pea.
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9. |
- Rasheed, Faiza, et al.
(author)
-
Structural architecture and solubility of native and modified gliadin and glutenin proteins : non-crystalline molecular and atomic organization
- 2014
-
In: RSC Advances. - 2046-2069. ; 4:4, s. 2051-2060
-
Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and its components, gliadin and glutenin proteins, form the largest polymers in nature, which complicates the structural architecture of these proteins. Wheat gluten, gliadin and glutenin proteins in unmodified form showed few secondary structural features. Structural modification of these proteins using heat, pressure and the chemical chaperone glycerol resulted in a shift to organized structure. In modified gliadin, nano-structural molecular arrangements in the form of hexagonal closed packed (HCP) assemblies with lattice parameter of (58 angstrom) were obvious together with development of intermolecular disulphide bonds. Modification of glutenin resulted in highly polymerized structure with proteins linked not only by disulphide bonds, but also with other covalent and irreversible bonds, as well as the highest proportion of beta-sheets. From a combination of experimental evidence and protein algorithms, we have proposed tertiary structure models of unmodified and modified gliadin and glutenin proteins. An increased understanding of gliadin and glutenin proteins structure and behavior are of utmost importance to understand the applicability of these proteins for various applications including plastic materials, foams, adhesives, films and coatings.
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10. |
- Rasheed, Faiza, et al.
(author)
-
The use of plants as a "green factory" to produce high strength gluten-based materials
- 2016
-
In: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 18:9, s. 2782-2792
-
Journal article (peer-reviewed)abstract
- The aim of the present study was to develop an understanding of how wheat plants can be used as a "green factory" by the modulation of genotype (G) and environmental (E) interactions to fine-tune the structure and increase the strength of gluten based materials. Two wheat genotypes (5 + 10 and 2 + 12) were grown under four nitrogen and two temperature regimes to obtain gluten of various characteristics. Protein microstructure morphology revealed by confocal laser scanning microscopy suggested a higher polymerisation of proteins in glycerol plasticized films from the 5 + 10 compared to the 2 + 12 genotype. Also, films with the highest Young's modulus and maximum stress were obtained from the 5 + 10 genotype, which might be explained by the higher number of cysteine residues and consequently more disulphide crosslinks in this genotype compared to the 2 + 12 one. The presence of two nano-scaled morphologies, hexagonal and lamellar structures and their internal relations were found to be of relevance for formation of beta-sheets and also to be related to performance (strength) of the material. Thus, plants could be used as a "green factory", avoiding the use of chemicals, to tune the tensile properties of the materials. Structural properties such as relatively low protein aggregation, high beta-sheet content and a high hexagonal to lamellar structural ratio at the nano-scale were found to yield films with high stiffness and strength.
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11. |
- Rasheed, Faiza, et al.
(author)
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Unraveling the Structural Puzzle of the Giant Glutenin Polymer-An Interplay between Protein Polymerization, Nanomorphology, and Functional Properties in Bioplastic Films
- 2018
-
In: ACS Omega. - : AMER CHEMICAL SOC. - 2470-1343. ; 3:5, s. 5584-5592
-
Journal article (peer-reviewed)abstract
- A combination of genotype, cultivation environment, and protein separation procedure was used to modify the nanoscale morphology, polymerization, and chemical structure of glutenin proteins from wheat. A low-polymerized glutenin starting material was the key to protein-protein interactions mainly via SS cross-links during film formation, resulting in extended beta-sheet structures and propensity toward the formation of nanoscale morphologies at molecular level. The properties of glutenin bioplastic films were enhanced by the selection of a genotype with a high number of cysteine residues in its chemical structure and cultivation environment with a short grain maturation period, both contributing positively to gluten strength. Thus, a combination of factors affected the structure of glutenins in bioplastic films by forming crystalline beta-sheets and propensity toward the ordered nanostructures, thereby resulting in functional properties with high strength, stiffness, and extensibility.
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12. |
- Agthe, Michael, et al.
(author)
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Following in Real Time the Two-Step Assembly of Nanoparticles into Mesocrystals in Levitating Drops
- 2016
-
In: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 16:11, s. 6838-6843
-
Journal article (peer-reviewed)abstract
- Mesocrystals composed of crystallographically aligned nanocrystals are present in biominerals and assembled materials which show strongly directional properties of importance for mechanical protection and functional devices. Mesocrystals are commonly formed by complex biomineralization processes and can also be generated by assembly of anisotropic nanocrystals. Here, we follow the evaporation-induced assembly of maghemite nanocubes into mesocrystals in real time in levitating drops. Analysis of time-resolved small-angle X-ray scattering data and ex situ scanning electron microscopy together with interparticle potential calculations show that the substrate-free, particle-mediated crystallization process proceeds in two stages involving the formation and rapid transformation of a dense, structurally disordered phase into ordered mesocrystals. Controlling and tailoring the particle-mediated formation of mesocrystals could be utilized to assemble designed nanoparticles into new materials with unique functions.
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13. |
- Berntsson, Oskar, et al.
(author)
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A setup for millisecond time-resolved X-ray solution scattering experiments at the CoSAXS beamline at the MAX IV Laboratory
- 2022
-
In: Journal of Synchrotron Radiation. - 0909-0495. ; 29, s. 555-562
-
Journal article (peer-reviewed)abstract
- The function of biomolecules is tightly linked to their structure, and changes therein. Time-resolved X-ray solution scattering has proven a powerful technique for interrogating structural changes and signal transduction in photoreceptor proteins. However, these only represent a small fraction of the biological macromolecules of interest. More recently, laser-induced temperature jumps have been introduced as a more general means of initiating structural changes in biomolecules. Here we present the development of a setup for millisecond time-resolved X-ray solution scattering experiments at the CoSAXS beamline, primarily using infrared laser light to trigger a temperature increase, and structural changes. We present results that highlight the characteristics of this setup along with data showing structural changes in lysozyme caused by a temperature jump. Further developments and applications of the setup are also discussed.
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14. |
- Blomfeldt, Thomas O. J., et al.
(author)
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Novel freeze-dried foams from glutenin- and gliadin-rich fractions
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:16, s. 6617-6627
-
Journal article (peer-reviewed)abstract
- This is the first study on freeze-dried foams prepared from glutenin- and gliadin-rich fractions of wheat gluten and blends thereof. It was found that the foam density and stiffness could be controlled by a suitable choice of the glutenin/gliadin ratio. The glutenin-rich samples had the highest foam densities and the density decreased with increasing gliadin content. The compression modulus also decreased with increasing gliadin content, which was explained by the decrease in foam density, a more open porosity and the more aggregated/polymerized structure in the presence of glutenin. IR and SE-HPLC revealed that the least aggregated foams were those consisting only of the gliadin-rich fraction. Confocal laser scanning microscopy revealed the presence of both HMW-glutenin and gliadin (to a certain extent probably resisting the ethanol extraction process) in the glutenin-rich foams. SAXS indicated that the gliadin-rich fraction contributed with weakly correlated protein aggregates with a characteristic distance of 40-43 Å.
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15. |
- Ceresino, Elaine Berger, et al.
(author)
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Lupin Protein Isolate Structure Diversity in Frozen-Cast Foams : Effects of Transglutaminases and Edible Fats
- 2021
-
In: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 26:6
-
Journal article (peer-reviewed)abstract
- This study addresses an innovative approach to generate aerated foods with appealing texture through the utilization of lupin protein isolate (LPI) in combination with edible fats. We show the impact of transglutaminases (TGs; SB6 and commercial), glycerol (Gly), soy lecithin (Lec) and linoleic acid (LA) on the micro- and nanostructure of health promoting solid foods created from LPI and fats blends. 3-D tomographic images of LPI with TG revealed that SB6 contributed to an exceptional bubble spatial organization. The inclusion of Gly and Lec decreased protein polymerization and also induced the formation of a porous layered material. LA promoted protein polymerization and formation of homogeneous thick layers in the LPI matrix. Thus, the LPI is a promising protein resource which when in blend with additives is able to create diverse food structures. Much focus has been placed on the great foamability of LPI and here we show the resulting microstructure of LPI foams, and how these were improved with addition of TGs. New food applications for LPI can arise with the addition of food grade dispersant Lec and essential fatty-acid LA, by improved puffiness, and their contributing as replacer of chemical leavening additives in gluten-free products.
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16. |
- Da Silva, Laura C.E., et al.
(author)
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Solvent-free and biocompatible multiphased organic-inorganic hybrid nanocomposites
- 2018
-
In: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 14:9, s. 1709-1718
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Journal article (peer-reviewed)abstract
- Biocompatible chemically cross-linked organic-inorganic (O-I) hybrid nanocomposites were developed using a new atoxic, simple and fast, solvent-free pathway. Poly(ϵ-caprolactone) (PCL) and poly(ethylene glycol) (PEG), which are both biocompatible, were used as the organic moieties (at different PCL/PEG ratios), while in situ synthesized polysilsesquioxanes made up the inorganic moiety. The O-I hybrid nanocomposites' molecular structures were characterized using solid-state 29Si NMR, TGA and ATR-IR. Results showed an unusually high condensation yield of approximately 90% and two distinct silsesquioxane structures. No traces of the remaining isocyanate groups were found. Advanced morphological characterization of the ternary O-I hybrids was performed using a combination of electron microscopy and X-ray scattering techniques such as SEM, TEM, ESI-TEM, WAXS and temperature-dependent SAXS. Results showed the occurrence of spherical nanoparticles, associated with polysilsesquioxane, and ordered network grains, associated with PCL and/or PEG chains cross-linked by silsesquioxane cages. As a consequence, a four-phased nanostructured morphology was proposed. In this model, PCL and PEG are undistinguishable, while polysilsesquioxane nanoparticles are uniformly distributed throughout a homogeneous cross-linked matrix, which shows gel-like behavior. Moreover, a mobile phase made up of unbound polymer chains occurs at the grain interface.
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17. |
- Diuk Andrade, Fabiana, et al.
(author)
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An insight into molecular motions and phase composition of gliadin/glutenin glycerol blends studied by 13C solid-state and 1H time-domain NMR
- 2018
-
In: Journal of Polymer Science, Part B: Polymer Physics. - : Wiley. - 0887-6266 .- 1099-0488. ; 56:9, s. 739-750
-
Journal article (peer-reviewed)abstract
- Monitoring of the molecular motions and secondary structures of gliadin (Gli) and glutenin (Glu) in blends with 10, 20, 30, and 40% glycerol was performed by solid-state (SS) and time domain (TD) NMR spectroscopy. Increasing the glycerol content increased the relative amount of β-sheets and disordered structures, while decreasing α-helices in Gli/Glu–glycerol blends studied by 13C CPMAS NMR. For ≥20% glycerol samples, the protein side-chain mobility increased similarly for Gli and Glu. A higher proportion of α-helices versus β-sheets was found in Gli-glycerol blends compared with Glu–glycerol blends. Glycerol acted as “immobilized” in 10–20% glycerol Gli samples and was found mainly “free” in 30 and 40% glycerol Gli/Glu samples. During temperature experiments, 30 and 40% glycerol amounts impacted the dynamic molecular behavior of the Gli and Glu proteins differently than lipids, as observed by TD-NMR. The combination of TD-NMR together with SS-NMR showed details of the dynamic molecular variations in Gli/Glu protein structure and are promising techniques to monitor the molecular dynamics of plasticized proteins.
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18. |
- Germiniani, Luiz G.L., et al.
(author)
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Poly(ε-caprolactone)/cellulose nanocrystal nanocomposite mechanical reinforcement and morphology : the role of nanocrystal pre-dispersion
- 2019
-
In: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 54:1, s. 414-426
-
Journal article (peer-reviewed)abstract
- Cellulose nanocrystal (CNC) incorporation in polymeric matrices is an environmentally friendly approach to mechanical reinforcement. In general, significant mechanical reinforcement can only be achieved by means of good CNC dispersion at random orientation. These primary characteristics are even more relevant for the preparation of nanocomposites based on hydrophobic matrices, such as poly(ε-caprolactone) (PCL). A straightforward approach to improve CNC dispersion in hydrophobic matrices is their surface modification. However, this extra step is usually complex and often impairs particle–particle interactions, which are also key to mechanical reinforcement. In this work, poly(ε-caprolactone)/neat cellulose nanocrystal nanocomposites were prepared by a specific procedure that combined solvent exchange and solvent casting methodologies, avoiding the use of any additives or chemical modification. These nanocomposites were investigated in terms of the CNC percolation network formation and its effect on the overall mechanical properties. The results showed that significant mechanical reinforcement was obtained, reaching a 155% Young’s modulus increase at 25 wt% CNC content. TEM showed a percolated network in the PCL/CNC25 nanocomposite. In terms of morphology and nanostructure, increasing CNC concentration also promoted a reduction in PCL spherulite size and lamellar thickness. These results pointed out to CNC preferential localization in the interfibrillar region. In conclusion, the solvent exchange methodology presented herein led to mechanically reinforced PCL/CNC nanocomposites with small crystalline domains intertwined with a percolated CNC network.
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19. |
- Gillams, Richard J., et al.
(author)
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Formation of Inverse Topology Lyotropic Phases in Dioleoylphosphatidylcholine/Oleic Acid and Dioleoylphosphatidylethanolamine/Oleic Acid Binary Mixtures
- 2014
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 30:12, s. 3337-3344
-
Journal article (peer-reviewed)abstract
- The addition of saturated fatty acids (FA) to phosphatidylcholine lipids (PC) that have saturated acyl chains has been shown to promote the formation of lyotropic liquidcrystalline phases with negative mean curvature. PC/FA mixtures may exhibit inverse bicontinuous cubic phases (Im3m, Pn3m) or inverse topology hexagonal phases (HII), depending on the length of the acyl chains/fatty acid. Here we report a detailed study of the phase behavior of binary mixtures of dioleoylphosphatidylcholine (DOPC)/oleic acid (OA) and dioleoylphosphatidylethanolamine (DOPE)/oleic acid at limiting hydration, constructed using small-angle X-ray diffraction (SAXD) data. The phase diagrams of both systems show a succession of phases with increasing negative mean curvature with increasing OA content. At high OA concentrations, we have observed the occurrence of an inverse micellar Fd3m phase in both systems. Hitherto, this phase had not been reported for phosphatidylethanolamine/fatty acid mixtures, and as such it highlights an additional route through which fatty acids may increase the propensity of bilayer lipid membranes to curve. We also propose a method that uses the temperature dependence of the lattice parameters of the HII phases to estimate the spontaneous radii of curvature (R0) of the binary mixtures and of the component lipids. Using this method, we calculated the R0 values of the complexes comprising one phospholipid molecule and two fatty acid molecules, which have been postulated to drive the formation of inverse phases in PL/FA mixtures. These are −1.8 nm (±0.4 nm) for DOPC(OA)2 and −1.1 nm (±0.1 nm) for DOPE(OA)2. R0 values estimated in this way allow the quantification of the contribution that different lipid species make to membrane curvature elastic properties and hence of their effect on the function of membrane-bound proteins.
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20. |
- Jansson, Maria, et al.
(author)
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Intercalation of cationic peptides within Laponite layered clay minerals in aqueous suspensions : The effect of stoichiometry and charge distance matching
- 2019
-
In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 557, s. 767-776
-
Journal article (peer-reviewed)abstract
- Clays can be synthesised to have specific functional properties, which have been exploited in a range of industrial processes. A key characteristic of clay is the presence of a negatively charged surface, surrounded by an oppositely charged rim. Because of that, clays are able to sequester cationic compounds resulting in the formation of ordered layered structures, known as tactoids. Recent research has highlighted the possibility of utilising clay as a drug delivery compound for cationic peptides. Here, we investigate the process of intercalation by using the highly cationic peptide deca-arginine, and the synthetic clay Laponite, in aqueous suspensions with 2.5 wt% Laponite, and varying peptide concentrations. Small-angle X-ray scattering experiments show that tactoids are formed as a function of deca-arginine concentration in the dispersion, and for an excess of peptide, i.e. above a matched charge-ratio between the peptide and clay, the growth of the tactoids is limited, resulting in tactoidal dissolution. Zeta-potential measurements confirm that the observed dissolution is caused by overcharging of the platelets. By employing coarse-grained molecular dynamics simulations based on the continuum model, we are able to predict the tactoid formation, the growth, and the dissolution, in agreement with experimental results. We propose that the present simulation method can be a useful tool to tune peptide and clay characteristics to optimise and determine the extent of intercalation by cationic peptides of therapeutic interest.
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21. |
- Jansson, Maria, et al.
(author)
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The effect of the relative permittivity on the tactoid formation in nanoplatelet systems. A combined computer simulation, SAXS, and osmotic pressure study
- 2018
-
In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797. ; 513, s. 575-584
-
Journal article (peer-reviewed)abstract
- The structural properties, and the intracrystalline swelling of Na+-, and Ca2+-montmorillonite (Na-, and Ca-mmt) have been investigated as an effect of decreasing the relative permittivity of the solvent, i.e. from water to ethanol (EtOH), utilizing the experimental techniques; small angle X-ray scattering (SAXS) and osmotic pressure measurements. The experimental data were compared with the continuum model, utilizing coarse-grained molecular dynamics bulk simulations, Monte Carlo simulations of two infinite parallel surfaces corresponding to two clay platelets, and the strong coupling theory. It was found that it is possible to tune the electrostatic interactions to obtain a transition from a repulsive to an attractive system for the Na-mmt by increasing the EtOH concentration, i.e. the Bjerrum length increases, and hence, the attractive ion-ion correlation forces are enhanced. A qualitative agreement was observed between the simulations and the experimental results. Moreover, a non-monotonic behavior of the intracrystalline swelling of Ca-mmt as a function of EtOH concentration was captured experimentally, where an increase in the osmotic pressure, and hence, an increase in the d-spacing was found at low concentrations, indicating that repulsive short-ranged interactions dominate in the system. Theoretically, the non-monotonic behavior could not be captured with the continuum model, probably due to the limitation that the electrostatic interactions solely enters the Hamiltonian via the Bjerrum length.
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22. |
- Johansson, Eva, et al.
(author)
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Wheat gluten polymer structures : The impact of genotype, environment, and processing on their functionality in various applications
- 2013
-
In: Cereal Chemistry. - 0009-0352 .- 1943-3638. ; 90:4, s. 367-376
-
Journal article (peer-reviewed)abstract
- For a number of applications, gluten protein polymer structures are of the highest importance in determining end-use properties. The present article focuses on gluten protein structures in the wheat grain, genotype- and environment-related changes, protein structures in various applications, and their impact on quality. Protein structures in mature wheat grain or flour are strongly related to end-use properties, although influenced by genetic and environment interactions. Nitrogen availability during wheat development and genetically determined plant development rhythm are the most important parameters determining the gluten protein polymer structure, although temperature during plant development interacts with the impact of the mentioned parameters. Glutenin subunits are the main proteins incorporated in the gluten protein polymer in extracted wheat flour. During dough mixing, gliadins are also incorporated through disulfide-sulfhydryl exchange reactions. Gluten protein polymer size and complexity in the mature grain and changes during dough formation are important for breadmaking quality. When using the gluten proteins to produce plastics, additional proteins are incorporated in the polymer through disulfide-sulfhydryl exchange, sulfhydryl oxidation, β-eliminations with lanthionine formation, and isopeptide formation. In promising materials, the protein polymer structure is changed toward β-sheet structures of both intermolecular and extended type and a hexagonal close-packed structure is found. Increased understanding of gluten protein polymer structures is extremely important to improve functionality and end-use quality of wheat- and gluten-based products.
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23. |
- Kahnt, Maik, et al.
(author)
-
Measurement of the coherent beam properties at the CoSAXS beamline
- 2021
-
In: Journal of Synchrotron Radiation. - 0909-0495. ; 28, s. 1948-1953
-
Journal article (peer-reviewed)abstract
- The CoSAXS beamline at the MAX IV Laboratory is a modern multi-purpose (coherent) small-Angle X-ray scattering (CoSAXS) instrument, designed to provide intense and optionally coherent illumination at the sample position, enabling coherent imaging and speckle contrast techniques. X-ray tracing simulations used to design the beamline optics have predicted a total photon flux of 1012-1013 photons s-1 and a degree of coherence of up to 10% at 7.1 keV. The normalized degree of coherence and the coherent flux of this instrument were experimentally determined using the separability of a ptychographic reconstruction into multiple mutually incoherent modes and thus the Coherence in the name CoSAXS was verified. How the beamline can be used both for coherent imaging and XPCS measurements, which both heavily rely on the degree of coherence of the beam, was demonstrated. These results are the first experimental quantification of coherence properties in a SAXS instrument at a fourth-generation synchrotron light source.
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24. |
- Kuktaite, Ramune, et al.
(author)
-
Changes in the hierarchical protein polymer structure : Urea and temperature effects on wheat gluten films
- 2012
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:31, s. 11908-11914
-
Journal article (peer-reviewed)abstract
- Understanding bio-based protein polymer structures is important when designing new materials with desirable properties. Here the effect of urea on the wheat gluten (WG) protein structure in WG-urea films was investigated. Small-angle X-ray scattering indicated the formation of a hexagonal close-packed (HCP) hierarchical structure in the WG-urea materials. The HCP structure was influenced significantly by the urea concentration and processing conditions. The interdomain distance d I between the HCP scattering objects increased with increasing content of urea and the objects seemed to be oriented in the extrusion direction. Additionally, the effect of temperature on the HCP structure was studied and it was shown that at ≥55°C the HCP structure disappeared. Transmission electron microscopy revealed a rather denatured pattern of both HMW-glutenins and gliadins in the WG-urea films. The molecular packing of the WG protein polymer can be highly affected by an additive and the processing method used.
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25. |
- Kuktaite, Ramune, et al.
(author)
-
Gluten biopolymer and nanoclay-derived structures in wheat gluten-urea-clay composites
- 2014
-
In: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
-
Journal article (peer-reviewed)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the C15A system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the C15 clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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26. |
- Kuktaite, Ramune, et al.
(author)
-
Gluten Biopolymer and Nanoclay-Derived Structures in Wheat Gluten-Urea-Clay Composites: Relation to Barrier and Mechanical Properties
- 2014
-
In: ACS Sustainable Chemistry & Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:6, s. 1439-1445
-
Journal article (peer-reviewed)abstract
- Here, we investigated the structure of natural montmorillonite (MMT) and modified Cloisite C15A (MMT pre-intercalated with a dimethyl-dehydrogenated tallow quaternary ammonium surfactant) nanoclays in the wheat gluten-urea matrix in order to obtain a nanocomposite with improved barrier and mechanical properties. Small-angle X-ray scattering indicated that the characteristic hexagonal closed packed structure of the wheat gluten-urea matrix was not found in the CISA system and existed only in the 3 and 5 wt % MMT composites. SAXS/WAXS, TGA, and water vapor/oxygen barrier properties indicated that the dispersion of the C15A clay was somewhat better than the natural MMT clay. Confocal laser scanning microscopy showed MMT clay clusters and C15A clay particles dispersed in the protein matrix, and these were preferentially oriented in the extrusion direction only at 5 wt % of the CIS clay. The water vapor/oxygen barrier properties were improved with the presence of clay. Independent of the clay content used, the stiffness decreased and the extensibility increased in the presence of C15A due to the surfactant induced changes on the protein. The opposite "more expected" clay effect (increasing stiffness and decreasing extensibility) was observed for the MMT composites.
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27. |
- Kuktaite, Ramune, et al.
(author)
-
Innovatively processed quinoa (Chenopodium quinoa Willd.) food : chemistry, structure and end-use characteristics
- 2022
-
In: Journal of the Science of Food and Agriculture. - : Wiley. - 0022-5142 .- 1097-0010. ; 102:12, s. 5065-5076
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Quinoa (Chenopodium quinoa Willd.) flour and processed traditional Peruvian quinoa breakfast foods were studied to evaluate the effect of extrusion and post-processing on protein properties, morphology and nutritional characteristics (amino acids and dietary fibers). RESULTS: The extrusion increased quinoa protein crosslinking and aggregation observed by size exclusion high-performance liquid chromatography and the amount of soluble fibers, as well as decreasing the amounts of insoluble fibers in the processed foods. The post-processing drying resulted in additional crosslinking of large protein fractions in the quinoa products. The microstructure of the extruded quinoa breakfast flakes and heat-post-processed samples studied by scanning electron microscopy and X-ray tomography differed greatly; post-drying induced formation of aerated protein microstructures in the heat-treated samples. Nanostructures revealed by small-angle and wide-angle X-ray scattering indicated that extrusion imparted morphological changes in the quinoa protein and starch (dominance of V-type). Overall, extrusion processing only reduced the content of most of the essential amino acids to a minor extent; the content of valine and methionine was reduced to a slightly greater extent, but the final products met the requirements of the Food and Drug Organization. CONCLUSION: This study presents innovative examples on how extrusion processing and post-processing heat treatment can be used to produce attractive future food alternatives, such as breakfast cereal flakes and porridge powder, from quinoa grains. Extrusion of quinoa flour into Peruvian foods was shown to be mostly impacted by the processing temperature and processing conditions used. Protein crosslinking increased due to extrusion and post-processing heating. Starch crystallinity decreased most when the product was dried after processing.
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28. |
- Kuktaite, Ramune, et al.
(author)
-
Structure and Morphology of Wheat Gluten Films : From Polymeric Protein Aggregates toward Superstructure Arrangements
- 2011
-
In: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:5, s. 1438-1448
-
Journal article (peer-reviewed)abstract
- Evaluation of structure and morphology of extruded wheat gluten (WG) films showed WG protein assemblies elucidated on a range of length scales from nano (4.4 angstrom and 9 to 10 angstrom, up to 70 angstrom) to micro (10 mu m). The presence of NaOH in WG films induced a tetragonal structure with unit cell parameters, a = 51.85 angstrom and c = 40.65 angstrom, whereas NH4OH resulted in a bidimensional hexagonal close-packed (HCP) structure with a lattice parameter of 70 angstrom. In the WG films with NH4OH, a highly polymerized protein pattern with intimately mixed glutenins and gliadins bounded through SH/SS interchange reactions was found. A large content of beta-sheet structures was also found in these films, and the film structure was oriented in the extrusion direction. In conclusion, this study highlights complexities of the supramolecular structures and conformations of wheat gluten polymeric proteins in biofilms not previously reported for biobased materials.
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29. |
- Liu, Jinrong, 1995-, et al.
(author)
-
High-yield production of lignin photonic crystals with ethanol and water
-
Other publication (other academic/artistic)abstract
- Structural colors in nature have inspired research into engineered photonic materials starting from renewable resources such as lignin extracted from wood and agricultural residues. A notable obstacle in developing lignin-based photonic crystals lies in the use of hazardous organic solvents, giving rise to safety and environmental concerns. Additionally, low product yields hinder scalable production of lignin photonics. Here, we report a highly efficient method for the fabrication of colloidal lignin particles of predicable size for producing photonic crystals using ethanol and water as the sole solvents. We achieved a 78% mass yield of photonic crystals starting from a crude soda lignin, resulting in vibrant colors spanning the entire visible spectrum. Controlling the particle size can be achieved by varying the dilution rate of a lignin ethanol solution with water, enabling the direct generation of colloidal crystals of preferred colors. The new method paves the way for large-scale development of lignin photonics.
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30. |
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31. |
- Magkakis, Konstantinos, et al.
(author)
-
Real-time structural characterization of protein response to a caged compound by fast detector readout and high-brilliance synchrotron radiation
- 2024
-
In: Structure. - : Elsevier. - 0969-2126 .- 1878-4186.
-
Journal article (peer-reviewed)abstract
- Protein dynamics are essential to biological function, and methods to determine such structural rearrangements constitute a frontier in structural biology. Synchrotron radiation can track real-time protein dynamics, but accessibility to dedicated high-flux single X-ray pulse time-resolved beamlines is scarce and protein targets amendable to such characterization are limited. These limitations can be alleviated by triggering the reaction by laser-induced activation of a caged compound and probing the structural dynamics by fast-readout detectors. In this work, we established time-resolved X-ray solution scattering (TR-XSS) at the CoSAXS beamline at the MAX IV Laboratory synchrotron. Laser-induced activation of caged ATP initiated phosphoryl transfer in the adenylate kinase (AdK) enzyme, and the reaction was monitored up to 50 ms with a 2-ms temporal resolution achieved by the detector readout. The time-resolved structural signal of the protein showed minimal radiation damage effects and excellent agreement to data collected by a single X-ray pulse approach.
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32. |
- Mota-Santiago, Pablo, et al.
(author)
-
In situ biaxial loading and multi-scale deformation measurements of nanostructured materials at the CoSAXS beamline at MAX IV Laboratory
- 2023
-
In: Journal of Applied Crystallography. - 0021-8898. ; 56, s. 967-975
-
Journal article (peer-reviewed)abstract
- Characterization of the mechanical response of polymers and composite materials relies heavily on the macroscopic stress-strain response in uniaxial tensile configurations. To provide representative information, the deformation process must be homogeneous within the gauge length, which is a condition that is rarely achieved due to stress concentration or inhomogeneities within the specimen. In this work, the development of a biaxial mechanical testing device at the CoSAXS beamline at MAX IV Laboratory is presented. The design facilitates simultaneous measurement of small- and wide-angle X-ray scattering (SAXS/WAXS), allowing assessment of the microstructural configuration before, after and during the continuous deformation process at multiple length scales. The construction also supports multiple deformation conditions, while guaranteeing stability even at high loads. Furthermore, the mechanical experiments can be complemented with spatially resolved mesoscopic surface deformation measurements using 3D-surface digital image correlation (DIC). Polycarbonate (PC) was used to demonstrate the varied material response to multi-axial deformation, as PC is isotropic with a high glass transition temperature (∼150°) and high strength. As a result, a clear correlation between full-field methods and the microstructural information determined from WAXS measurements is demonstrated. When a uniaxial load is applied, homogeneous strain regions could be observed extending perpendicular to the applied load. When a secondary axial load was added (biaxial mode), it was observed that high strain domains were created near the centre of the sample and at the boundaries after yield. With increased strain, the deformation in the main deformation direction also increases. Mechanical reliability was demonstrated by carrying out static loading of polyacrylonitrile-based carbon fibre (CF) bundles. As a result, the nonlinear stiffening behaviour typically observed in CFs was seen, while no evidence of the creation of new voids during loading was observed. The results support the reliability and broad applicability of the developed technique.
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33. |
- Muneer, Faraz, et al.
(author)
-
Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties
- 2015
-
In: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 16:3, s. 695-705
-
Journal article (peer-reviewed)abstract
- In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.
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34. |
- Newson, William R., et al.
(author)
-
Commercial potato protein concentrate as a novel source for thermoformed bio-based plastic films with unusual polymerisation and tensile properties
- 2015
-
In: RSC Advances. - 2046-2069. ; 5:41, s. 32217-32226
-
Journal article (peer-reviewed)abstract
- Commercial potato protein concentrate (PPC) was investigated as a source of thermoformed bio-based plastic film. Pressing temperatures of 100 to 190 degrees C with 15 to 25% glycerol were used to form PPC films. The shape of the tensile stress-strain curve in thermoformed PPC was controlled by glycerol level and was independent of processing temperature. Tensile testing revealed that elongation at break increased with processing temperature while Young's modulus was unaffected by processing temperature, both in contrast to previous results in protein based systems. Also in contrast to previous studies, Young's modulus was found to be only sensitive to glycerol level. Maximum tensile stress increased with increasing processing temperature for PPC films. Maximum stress and strain at break correlated with the extractable high molecular weight protein content of the processed films measured with size exclusion chromatography. Infrared absorption indicated that the content of beta-sheet structure increased from the commercial protein concentrate to that pressed at 100 degrees C, but did not further develop with increasing press temperature. Changes in structural arrangements were observed by small angle X-ray scattering indicating the development of different correlation distances with processing temperature but with no clear long range order at the supramolecular level. The novel Young's modulus behaviour appears to be due to constant secondary structure or the effect of aggregated protein structure formed during protein production. Unique strain at break behaviour with processing temperature was demonstrated, likely due to new connections formed between those aggregates.
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35. |
- Nickel, Anne C., et al.
(author)
-
Beyond simple self-healing : How anisotropic nanogels adapt their shape to their environment
- 2022
-
In: The Journal of chemical physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 157:19, s. 194901-194901
-
Journal article (peer-reviewed)abstract
- The response of soft colloids to crowding depends sensitively on the particles' compressibility. Nanogel suspensions provide model systems that are often studied to better understand the properties of soft materials and complex fluids from the formation of colloidal crystals to the flow of viruses, blood, or platelet cells in the body. Large spherical nanogels, when embedded in a matrix of smaller nanogels, have the unique ability to spontaneously deswell to match their size to that of the nanogel composing the matrix. In contrast to hard colloids, this self-healing mechanism allows for crystal formation without giving rise to point defects or dislocations. Here, we show that anisotropic ellipsoidal nanogels adapt both their size and their shape depending on the nature of the particles composing the matrix in which they are embedded. Using small-angle neutron scattering with contrast variation, we show that ellipsoidal nanogels become spherical when embedded in a matrix of spherical nanogels. In contrast, the anisotropy of the ellipsoid is enhanced when they are embedded in a matrix of anisotropic nanogels. Our experimental data are supported by Monte Carlo simulations that reproduce the trend of decreasing aspect ratio of ellipsoidal nanogels with increasing crowding by a matrix of spherical nanogels.
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36. |
- Peruzzo, Pablo J., et al.
(author)
-
On the strategies for incorporating nanosilica aqueous dispersion inthe synthesis of waterborne polyurethane/silica nanocomposites:Effects on morphology and properties
- 2016
-
In: Materials Today Communications. - : Elsevier BV. - 2352-4928. ; 6, s. 81-91
-
Journal article (peer-reviewed)abstract
- In this work the synthesis of waterborne polyurethane/nanosilica nanocomposites by using two differ-ent strategies is presented, starting from a vinyl terminated polyurethane prepolymer (PUP) based onisophorone diisocyanate and polypropylene glycol, and varying the nanosilica content. In one case, thePUP was dispersed in an aqueous solution containing glycerol-functionalized colloidal nanosilica parti-cles and the dispersion was further polymerized; in the other case, the PUP was dispersed in an aqueousmedia, then colloidal nanosilica was added to the dispersion and then polymerized. A physical mixturewas also prepared for comparative purpose. Films were prepared by casting of the aqueous dispersion.The morphology of the dispersions and films depended on the incorporation route of nanoparticles aswas observed by SAXS, SEM and TEM. While the blends had significantly less hydrogen bonding betweenthe hard segments of the PU and nanosilica particles, samples prepared by the two different methodsproposed in this work showed an strong interaction between both materials in agreement with FTIR andDSC results. Synthesis pathway plays an important role in order to obtain high performance waterbornepolyurethane/nanosilica composites, since final properties of the films also depended on the nanoparticleincorporation strategy.
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37. |
- Plivelic, Tomás S., et al.
(author)
-
X-ray tracing, design and construction of an optimized optics scheme for CoSAXS, the small angle x-ray scattering beamline at MAX IV laboratory
- 2019
-
In: Proceedings of the 13th International Conference on Synchrotron Radiation Instrumentation, SRI 2018. - : Author(s). - 9780735417823 ; 2054
-
Conference paper (peer-reviewed)abstract
- A novel optical design for a flexible SAXS beamline at a modern synchrotron has been implemented for the CoSAXS beamline at the 3GeV ring at the MAX TV Laboratory. The performance of the beamline has been simulated through combined ray tracing and wave propagation with the code xrt taking into account the low emittance and highly coherent beam of MAX TV and the short inter-optics distances of the beamline. The total photon flux is estimated to be 1012-1013 ph/s with the coherent flux portion up to 10 % at 7.1 keV. The inhomogeneities in the X-ray beam arising from use of real (non-idealised) mirror surfaces are also modelled using the measured slope profiles of the mirrors. Strategies to mitigate these inhomogeneities are discussed. The optical components for CoSAXS have been constructed and beamline commissioning will start in 2019.
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38. |
- Rasheed, Faiza, et al.
(author)
-
Macromolecular changes and nano-structural arrangements in gliadin and glutenin films upon chemical modification Relation to functionality
- 2015
-
In: International Journal of Biological Macromolecules. - : Elsevier BV. - 0141-8130 .- 1879-0003. ; 79, s. 151-159
-
Journal article (peer-reviewed)abstract
- Protein macromolecules adopted for biological and bio-based material functions are known to develop a structured protein network upon chemical modification. In this study, we aimed to evaluate the impact of chemical additives such as, NaOH, NH4OH and salicylic acid (SA), on the secondary and nano-structural transitions of wheat proteins. Further, the effect of chemically induced modifications in protein macromolecular structure was anticipated in relation to functional properties. The gliadin-NH4OH-SA film showed a supramolecular protein organization into hexagonal structures with 65 angstrom lattice parameter, and other not previously observed structural entities having a characteristic distance of 50 angstrom. Proteins in gliadin-NH4OH-SA films were highly polymerized, with increased amount of disulfide crosslinks and beta-sheets, causing improved strength and stiffness. Glutenin and WG proteins with NH4OH-SA showed extensive aggregation and an increase in beta-sheet content together with irreversible crosslinks. Irreversible crosslinks hindered a high order structure formation in glutenins, and this resulted in films with only moderately improved stiffness. Thus, formation of nano-hierarchical structures based on beta-sheets and disulfide crosslinks are the major reasons of high strength and stiffness in wheat protein based films.
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39. |
- Rasheed, Faiza, et al.
(author)
-
Mild gluten separation - A non-destructive approach to fine tune structure and mechanical behavior of wheat gluten films
- 2015
-
In: Industrial Crops and Products. - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 73, s. 90-98
-
Journal article (peer-reviewed)abstract
- Despite the increasing production of wheat gluten (WG) for industrial use, minor attention has been given to the impact of the separation procedure on the gluten quality. The purpose of the present study was to probe the effect of the separation treatments (harsh vs mild) on gluten structure, morphology, and performance in bio-based films. The harshly separated industrial WG showed aggregated and pre-cross linked structure in the starting material most likely due to shear forces during gluten separation from flour and heat effect during the drying procedures. Further, when the harshly separated WG was processed into films the pre-crosslinked starting material restricted new crosslinks formation and structural rearrangements at nano-scale. The mechanical integrity of the film was also affected resulting in films with low Young's modulus and strength. WG (from cultivars Diskette, Puntari, and Sleipner) recovered from mild separation showed relatively "native" non-destructed crosslinking pattern and not previously observed structural morphology at nano-scale. When processed into films the mildly separated WG showed well polymerized intimately crosslinked proteins both with disulfide and other covalent crosslinks. The nano-scale morphology showed lamellar and hexagonal arrangements, not reported so far in any study. The structural rearrangements among films from mildly separated WG resulted in materials with improved mechanical integrity as compared to films from harshly separated WG. The present study showed that the quality of WG is significantly affected by the separation procedure which also affects protein polymerization, nano-scale morphology, and tensile properties of films. (C) 2015 Elsevier B.V. All rights reserved.
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40. |
- Rasheed, Faiza, et al.
(author)
-
Structural architecture and solubility of native and modified gliadin and glutenin proteins: non-crystalline molecular and atomic organization
- 2014
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 4:4, s. 2051-2060
-
Journal article (peer-reviewed)abstract
- Wheat gluten (WG) and its components, gliadin and glutenin proteins, form the largest polymers in nature, which complicates the structural architecture of these proteins. Wheat gluten, gliadin and glutenin proteins in unmodified form showed few secondary structural features. Structural modification of these proteins using heat, pressure and the chemical chaperone glycerol resulted in a shift to organized structure. In modified gliadin, nano-structural molecular arrangements in the form of hexagonal closed pack (HCP) assemblies with lattice parameter of (58 Å) were obvious together with development of intermolecular disulphide bonds. Modification of glutenin resulted in highly polymerized structure with proteins linked not only by disulphide bonds, but also with other covalent and irreversible bonds, as well as the highest proportion of b-sheets. From a combination of experimental evidence and protein algorithms, we have proposed tertiary structure models of unmodified and modified gliadin and glutenin proteins. An increased understanding of gliadin and glutenin proteins structure and behavior are of utmost importance to understand the applicability of these proteins for various applications including plastics materials, foams, adhesives, films and coatings.
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41. |
- Rasheed, Faiza, et al.
(author)
-
The use of plants as a “green factory” to produce high strength gluten-based materials
- 2016
-
In: Green Chemistry. - 1463-9270. ; 18:9, s. 2782-2792
-
Journal article (peer-reviewed)abstract
- The aim of the present study was to develop an understanding of how wheat plants can be used as a “green factory” by the modulation of genotype (G) and environmental (E) interactions to fine-tune the structure and increase the strength of gluten based materials. Two wheat genotypes (5 + 10 and 2 + 12) were grown under four nitrogen and two temperature regimes to obtain gluten of various characteristics. Protein microstructure morphology revealed by confocal laser scanning microscopy suggested a higher polymerisation of proteins in glycerol plasticized films from the 5 + 10 compared to the 2 + 12 genotype. Also, films with the highest Young’s modulus and maximum stress were obtained from the 5 + 10 genotype, which might be explained by the higher number of cysteine residues and consequently more disulphide crosslinks in this genotype compared to the 2 + 12 one. The presence of two nano-scaled morphologies, hexagonal and lamellar structures and their internal relations were found to be of relevance for formation of β-sheets and also to be related to performance (strength) of the material. Thus, plants could be used as a “green factory”, avoiding the use of chemicals, to tune the tensile properties of the materials. Structural properties such as relatively low protein aggregation, high β-sheet content and a high hexagonal to lamellar structural ratio at the nano-scale were found to yield films with high stiffness and strength.
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42. |
- Thuresson, Axel, et al.
(author)
-
Flocculated Laponite-PEG/PEO Dispersions with Multivalent Salt : A SAXS, Cryo-TEM, and Computer Simulation Study
- 2017
-
In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 121:13, s. 7387-7396
-
Journal article (peer-reviewed)abstract
- The aim of this study is to scrutinize the mechanism behind aggregation, i.e., tactoid formation of nanostructures with the shape of a platelet. For that purpose, the clay minerals Laponite and montmorillonite have been used as model systems. More specifically, we are interested in the role of: the platelet size, the electrostatic interactions, and adsorbing polymers. Our hypothesis is that the presence of PEG is crucial for tactoid formation if the system is constituted by small nanometric platelets. For this purpose, SAXS, USAXS, Cryo-TEM, and coarse-grained molecular dynamics simulations have been used to study how the formation and the morphology of the tactoids are affected by the platelet size. The simulations indicate that ion-ion correlations are not enough to induce large tactoids solely if the platelets are small and the absolute charge is too low, i.e., in the size and charge range of Laponite. When a polymer is introduced into the system, the tactoid size grows, and the results can be explained by weak attractive electrostatic correlation forces and polymer bridging. It is shown that when the salt concentration increases the long-ranged electrostatic repulsion is screened, and a free energy minimum appears at short distances due to the ion-ion correlation effects. When a strongly adsorbing polymer is introduced into the system, a second free energy minimum appears at a slightly larger separation. The latter dominates if the polymer is relatively long and/or the polymer concentration is high enough. (Graph Presented).
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43. |
- Thuresson, Axel, et al.
(author)
-
Temperature Response of Charged Colloidal Particles by Mixing Counterions Utilizing Ca2+/Na+ Montmorillonite as Model System
- 2017
-
In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 121:14, s. 7951-7958
-
Journal article (peer-reviewed)abstract
- The osmotic pressure and the aggregation of charged colloids as a function of temperature have been investigated using Monte Carlo and molecular dynamics simulations for different ratios of monovalent and divalent counterions. In the simulations the water is treated as a temperature-dependent dielectric continuum, and only the electrostatic interactions are considered. It was found that the temperature response can be controlled, i.e., the osmotic pressure can increase, decrease, or be kept constant, as a function of temperature depending on the monovalent/divalent counterion ratio. The increase in osmotic pressure with temperature, which occurs at low enough surface charge density and/or low fraction of divalent ions, can be understood from the DLVO theory. The origin of the opposite behavior can be explained by the enhanced attractive electrostatic ion-ion correlation interactions with temperature. The constraint is that the absolute value of the surface charge density of the colloids must be above a certain threshold, i.e., high enough such that the attractive ion-ion correlations can dominate the interaction regarding the divalent ions. The current conclusions are supported by the microstructural characterization of Ca2+/Na+-montmorillonite clay using small-angle X-ray scattering. A qualitative agreement is observed between the simulations and the experimental data.
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44. |
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45. |
- Wilson, Runcy, et al.
(author)
-
Clay Intercalation and its Influence on the Morphology and Transport Properties of EVA/Clay Nanocomposites
- 2012
-
In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 116:37, s. 20002-20014
-
Journal article (peer-reviewed)abstract
- Nanocomposite membranes based on poly-(ethylene-co-vinyl acetate) copolymer (18% vinyl acetate content)and two different organomodified clays have been prepared by mechanical mixing using two roll mill method. The morphology of the nanocomposites was investigated using small angle X-ray scattering, scanning electron microscopy, and transmission electron microscopy. The mechanical and thermal studies were also performed using universal testing machine and differential scanning calorimeter, respectively. Samples with low filler content showed excellent dispersion of layered silicates resulting in a partially exfoliated structure. The diffusion and transport of organic solvents through the membranes have been investigated in detail as a function of clay content, nature of solvent and clay, and temperature in the temperature range of 28−70 °C. The influence of free volume on the transport properties of the membranes was studied using positron annihilation lifetime spectroscopy. The solvent uptake was minimum for composites with 3 wt % of filler, and it get increased with increasing filler content, which is presumably due to aggregation of clay filler at higher loading. The transport phenomenon was found to follow an anomalous mode. Activation parameters were estimated, and the molar mass between cross-links was calculated. Finally, the experimental transport data were compared with theoretical predictions.
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46. |
- Wilson, Runcy, et al.
(author)
-
Preparation and Characterization of EVA/Clay Nanocomposites with Improved Barrier Performance
- 2012
-
In: Journal of Applied Polymer Science. - : Wiley. - 1097-4628 .- 0021-8995. ; 123:Online 30 September 2011, s. 3806-3818
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Journal article (peer-reviewed)abstract
- Poly (ethylene-co-vinyl acetate) (EVA)/clay nanocomposites containing two different organoclays with different clay loadings were prepared. The transport of gases (oxygen and nitrogen) through the composite membranes was investigated and the results were compared. These studies revealed that the incorporation of nanoclays in the polymer increased the efficiency of the membranes toward barrier properties. It was also found that the barrier properties of the membranes decreased with clay loadings. This is mainly due to the aggregation of clay at higher loadings. The morphology of the nanocomposites was studied by scanning electron microscopy, transmission electron microscopy and X-ray scattering. Small angle X-ray scattering results showed significant intercalation of the polymer chains between the organo-modified silicate layers in all cases. Better dispersed silicate layer stacking and more homogeneous membranes were obtained for Cloisite 25A based nanocomposites compared with Cloisite 20A samples. Microscopic observations (SEM and TEM) were coherent with those results. The dispersion of clay platelets seemed to be maximized for 3 wt % of clay and agglomeration increased with higher clay loading. Wide angle X-ray scattering results showed no significant modifications in the crystalline structure of the EVA matrix because of the presence of the clays. The effect of free volume on the transport behavior was studied using positron annihilation spectroscopy. The permeability results have been correlated with various permeation models.
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47. |
- 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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48. |
- 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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49. |
- 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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50. |
- 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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