| 31. |
- Kuktaite, Ramune, et al.
(författare)
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Changes in the hierarchical protein polymer structure : Urea and temperature effects on wheat gluten films
- 2012
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 2:31, s. 11908-11914
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Tidskriftsartikel (refereegranskat)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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| 32. |
- Kuktaite, Ramune, et al.
(författare)
-
Structure and Morphology of Wheat Gluten Films : From Polymeric Protein Aggregates toward Superstructure Arrangements
- 2011
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:5, s. 1438-1448
-
Tidskriftsartikel (refereegranskat)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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| 33. |
- Lehmuskero, Anni, et al.
(författare)
-
Plasmonic particles set into fast orbital motion by an optical vortex beam
- 2014
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Ingår i: Optics express. - : The Optical Society. - 1094-4087. ; 22:4, s. 4349-4356
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Tidskriftsartikel (refereegranskat)abstract
- We optically trap plasmonic gold particles in two dimensions and set them into circular motion around the optical axis using a helically phased vortex laser beam. The orbiting frequency of the particles reaches 86 Hz, which corresponds to a particle velocity of the order 1 mm per second, for an incident laser power of a few tens of milliwatts. The experimentally determined orbiting frequencies are found to be well in line with the notion that the beam carries an orbital angular momentum of ħl per photon.
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| 34. |
- Lind, Erik, et al.
(författare)
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High Frequency Performance of Vertical InAs Nanowire MOSFET
- 2010
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Ingår i: 2010 22Nd International Conference On Indium Phosphide And Related Materials (Iprm). - 1092-8669. - 9781424459193
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Konferensbidrag (refereegranskat)abstract
- We report on RF characterization of vertical, 100-nm-gate length InAs nanowire MOSFETs, utilizing wrap-gate technology and Al2O3 high-kappa gate oxide. The transistors show f(t)=5.6 GHz and f(max)=22 GHz, mainly limited by parasitic capacitances. The RF device performance is described using a hybrid-pi model taking hole generation at the drain into account. Electrostatic modeling of the parasitic capacitances for arrays of vertical nanowires indicates that a strong reduction in extrinsic capacitances can be achieved for devices with a small inter-wire separation.
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| 35. |
- Muneer, Faraz, et al.
(författare)
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Preparation, Properties, Protein Cross-Linking and Biodegradability of Plasticizer-Solvent Free Hemp Fibre Reinforced Wheat Gluten, Glutenin, and Gliadin Composites
- 2014
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 9:3, s. 5246-5261
-
Tidskriftsartikel (refereegranskat)abstract
- The present study is aimed at evaluating the use of plant-based polymers and fibres for the production of sustainable biocomposites. For the first time, plasticiser/solvent-free hemp fibre-reinforced wheat gluten and hemp-gliadin and glutenin composites were obtained by compression moulding at different temperatures. The plasticiser/solvent-free sample preparation method developed in this study facilitated the use of a powdered protein matrix with a mat of randomly oriented hemp fibres. The tensile and protein cross-linking properties, as well as the biodegradability, were investigated. The addition of hemp fibre to the protein matrix increased the E-modulus by 20 to 60% at 130 degrees C. An increase in moulding temperature from 110 to 130 degrees C resulted in an increase in maximum stress due to the formation of intermolecular bonds between protein chains. The gliadin composites had higher E-modulus and maximum stress and showed a larger increase in protein polymerisation with increased temperature compared to the gluten in composites. A comparison of tensile properties revealed that the composites were stiffer and stronger compared to several similarly produced biobased composites. The composites were found to be fully biodegradable under a simulated soil environment after 180 days. Biocomposites produced in the present study were found to be environmentally friendly with fairly good mechanical properties.
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| 36. |
- Newson, William, et al.
(författare)
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Effect of Additives on the Tensile Performance and Protein Solubility of Industrial Oilseed Residual Based Plastics
- 2014
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 62:28, s. 6707-6715
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Tidskriftsartikel (refereegranskat)abstract
- Ten chemical additives were selected from the literature for their proposed modifying activity in protein-protein interactions. These consisted of acids, bases, reducing agents, and denaturants and were added to residual deoiled meals of Crambe abyssinica (crambe) and Brassica carinata (carinata) to modify the properties of plastics produced through hot compression molding at 130 degrees C. The films produced were examined for tensile properties, protein solubility, molecular weight distribution, and water absorption. Of the additives tested, NaOH had the greatest positive effect on tensile properties, with increases of 105% in maximum stress and 200% in strain at maximum stress for crambe and a 70% increase in strain at maximum stress for carinata. Stiffness was not increased by any of the applied additives. Changes in tensile strength and elongation for crambe and elongation for carinata were related to changes in protein solubility. Increased pH was the most successful in improving the protein aggregation and mechanical properties within the complex chemistry of residual oilseed meals.
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| 37. |
- Newson, William, et al.
(författare)
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Oilseed Meal Based Plastics from Plasticized, Hot Pressed Crambe abyssinica and Brassica carinata Residuals
- 2013
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Ingår i: Journal of the American Oil Chemists Society. - : Wiley. - 0003-021X .- 1558-9331. ; 90:8, s. 1229-1237
-
Tidskriftsartikel (refereegranskat)abstract
- With the increased use of plant oils as sustainable feedstocks, industrial oilseed meal from Crambe abyssinica (crambe) and Brassica carinata (carinata) can become a potential source for oilseed meal based plastics. In this study, crambe and carinata oilseed meal plastics were produced with 10-30 % glycerol and compression molding at 100-180 A degrees C. Size exclusion HPLC was used to relate tensile properties to changes in protein solubility and molecular weight distribution. By combining glycerol and thermal processing, increased flexibility has been observed compared to previous work on unplasticized oilseed meal. Tensile results varied from a brittle crambe based material (10 % glycerol, 130 A degrees C), Young's modulus 240 MPa, strain at maximum stress of 2 %, to a soft and flexible carinata based material (30 % glycerol, 100 A degrees C), Young's modulus 6.5 MPa, strain at maximum stress of 13 %. Strength and stiffness development with increasing molding temperature is in agreement with the protein profiles obtained. Thus, the highest mechanical parameters were obtained at the protein solubility minimum at 140 A degrees C. Higher temperatures caused protein degradation, increasing the level of low molecular weight extractable proteins. In carinata based materials the strain at maximum stress decreased as the protein aggregation developed. Results presented indicate that both crambe and carinata oilseed meal based materials can have their properties modulated through thermal treatment and the addition of plasticizers.
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| 38. |
- Nordqvist, Emelie, et al.
(författare)
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An associative learning procedure measured by Event-Related Potentials correlates with event memory in 14 month old children
- 2011
-
Konferensbidrag (refereegranskat)abstract
- Deferred imitation (DI) reflects an early form of event memory but the underlying neural processes is to a large degree unknown. Thus, the present study examines how associative learning observed through event-related potentials (ERP) relates to DI as measured with an observation- only design.Thirty children participated in the study and acceptable ERP data was collected from 15 (9 boys). DI was measured with a thirty minutes delay and ERP was recorded with a Geodesic High Density Net with 128 electrodes. The ERP procedure consisted of two pairs of pictures presented six times (= the learning phase) and a test phase introducing two violations: Two familiar pictures in a new combination (ASSO) or a combination of one familiar and one novel picture (NOV). In addition, visual recognition memory was also measured.ERP revealed an Nc within 300-600 ms post stimuli. A higher mean amplitude was observed for ASSO (p < .05) and a marginal effect was noted for NOV (p = .055). Better DI performance correlated with larger Nc change scores between ASSO and the last presentation in the learning phase (rs (15) = .57; p < .05). Preliminary analyses of slow waves revealed no further relationship between ERP and DI and no significant correlation between DI and novelty preference. These findings indicate that electrophysiological indices of associative learning can be related to behavioral observations of early memory processes in young infants.
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| 39. |
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| 40. |
- Nordqvist, Emelie, et al.
(författare)
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An electrophysiological index of associative learning correlates with event memories in 14 month old children
- 2011
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Deferred imitation (DI) is an early form of event memory that indexes early individual differences in infant cognition but the underlying neural processes is to a large degree uncharted. The present study examines how event-related potentials (ERPs) as a response to an associative learning procedure relates to DI measured with an observation-only design. Thirty children participated and acceptable ERP data was collected from 15 (9 boys). DI was measured with a thirty minutes delay and ERP was recorded with a Geodesic High Density Net with 128 electrodes. The ERP procedure consisted of two pairs of pictures presented six times (= the learning phase) and a test phase introducing two violations: Two familiar pictures in a new combination (ASSO) or a combination of one familiar and one novel picture (NOV). In addition, visual recognition memory was also measured. ERP revealed an Nc within 300-600 ms post stimuli. A higher mean amplitude was observed for ASSO (p < .05) and a marginal effect was noted for NOV (p = .055). Better DI performance correlated with larger Nc change scores between ASSO and the last presentation in the learning phase (rs (15) = .57; p < .05). Preliminary analyses of early and late slow waves (800 to 1500ms post stimuli) revealed no further relationship between ERP and DI and no significant correlation between DI and visual recognition memory. This finding indicates a possible direct link between electrophysiological indices of learning and behavioral observations of declarative like memory processes in young infants.
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