| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Andersson, Jenny Marie, et al.
(författare)
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The plant dehydrin Lti30 stabilizes lipid lamellar structures in varying hydration conditions[S]
- 2020
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Ingår i: Journal of Lipid Research. - 0022-2275 .- 1539-7262. ; 61:7, s. 1014-1024
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Tidskriftsartikel (refereegranskat)abstract
- A major challenge to plant growth and survival are changes in temperature and diminishing water supply. During acute temperature and water stress, plants often express stress proteins, such as dehydrins, which are intrinsically disordered hydrophilic proteins. In this article, we investigated how the dehydrin Lti30 fromArabidopsis thalianastabilizes membrane systems that are exposed to large changes in hydration. We also compared the effects of Lti30 on membranes with those of the simple osmolytes urea and trimethylamineN-oxide. Using X-ray diffraction and solid-state NMR, we studied lipid-protein self-assembly at varying hydration levels. We made the following observations:1) the association of Lti30 with anionic membranes relies on electrostatic attraction, and the protein is located in the bilayer interfacial membrane region;2) Lti30 can stabilize the lamellar multilayer structure, making it insensitive to variations in water content;3) in lipid systems with a composition similar to those present in some seeds and plants, dehydrin can prevent the formation of nonlamellar phases upon drying, which may be crucial for maintaining membrane integrity; and4) Lti30 stabilizes bilayer structures both at high and low water contents, whereas the small osmolyte molecules mainly prevent dehydration-induced transitions. These results corroborate the idea that dehydrins are part of a sensitive and multifaceted regulatory mechanism that protects plant cells against stress.
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| 3. |
- Colafemmina, Giuseppe, et al.
(författare)
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The cooling process effect on the bilayer phase state of the CTAC/cetearyl alcohol/water surfactant gel
- 2020
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Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects. - : Elsevier BV. - 0927-7757. ; 597
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Tidskriftsartikel (refereegranskat)abstract
- Gel formation by surfactant molecules is generally controlled by thermodynamics rather than kinetics. Mixtures of long-chain alcohols and surfactants are widely used in various cosmetic and pharmaceutical products. The cooling rate used to produce the products is known to be a key parameter to control the rheological properties and the final texture. However, the physical-chemistry links between the cooling process and the rheological properties are still unknown. Here, we investigated the mechanical properties and microstructure of a surfactant gel formulated with cetyltrimethylammonium chloride (CTAC) and cetearyl alcohol in water by using a multi-technique approach involving rheology, small-angle X-ray scattering (SAXS) and diffusion NMR. The gels, formed by two cooling processes fast and slow cooling, respectively from a high-temperature mixture, have locally a lamellar structure with periodic repeat distances of 31.4 and 28.5 nm for fast and slow cooling, respectively. The cross-polarized microscopy images reveal the presence of multilamellar vesicles (MLVs). These data on the supramolecular aggregates allow rationalizing the mechanical behavior of the two samples. In fact, the elastic, G′, and the viscous, G′′, moduli were detected to be ca. 4 times higher for the fast-cooling (quenched) sample than for the slow-cooling (relaxed) sample.
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| 4. |
- Harlang, Tobias C. B., et al.
(författare)
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Iron sensitizer converts light to electrons with 92% yield
- 2015
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Ingår i: Nature Chemistry. - 1755-4330 .- 1755-4349. ; 7:11, s. 883-889
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy conversion in photovoltaics or photocatalysis involves light harvesting, or sensitization, of a semiconductor or catalyst as a first step. Rare elements are frequently used for this purpose, but they are obviously not ideal for large-scale implementation. Great efforts have been made to replace the widely used ruthenium with more abundant analogues like iron, but without much success due to the very short-lived excited states of the resulting iron complexes. Here, we describe the development of an iron-nitrogen-heterocyclic-carbene sensitizer with an excited-state lifetime that is nearly a thousand-fold longer than that of traditional iron polypyridyl complexes. By the use of electron paramagnetic resonance, transient absorption spectroscopy, transient terahertz spectroscopy and quantum chemical calculations, we show that the iron complex generates photoelectrons in the conduction band of titanium dioxide with a quantum yield of 92% from the 3MLCT (metal-to-ligand charge transfer) state. These results open up possibilities to develop solar energy-converting materials based on abundant elements.
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| 5. |
- Harlang, Tobias, et al.
(författare)
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Iron sensitizer converts light to electrons with 92% yield.
- 2015
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Ingår i: Nature Chemistry. - : Springer Science and Business Media LLC. - 1755-4330 .- 1755-4349. ; 7:11, s. 883-889
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Tidskriftsartikel (refereegranskat)abstract
- Solar energy conversion in photovoltaics or photocatalysis involves light harvesting, or sensitization, of a semiconductor or catalyst as a first step. Rare elements are frequently used for this purpose, but they are obviously not ideal for large-scale implementation. Great efforts have been made to replace the widely used ruthenium with more abundant analogues like iron, but without much success due to the very short-lived excited states of the resulting iron complexes. Here, we describe the development of an iron-nitrogen-heterocyclic-carbene sensitizer with an excited-state lifetime that is nearly a thousand-fold longer than that of traditional iron polypyridyl complexes. By the use of electron paramagnetic resonance, transient absorption spectroscopy, transient terahertz spectroscopy and quantum chemical calculations, we show that the iron complex generates photoelectrons in the conduction band of titanium dioxide with a quantum yield of 92% from the (3)MLCT (metal-to-ligand charge transfer) state. These results open up possibilities to develop solar energy-converting materials based on abundant elements.
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| 6. |
- Hudson, Lawrence N, et al.
(författare)
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The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project
- 2017
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 7:1, s. 145-188
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Tidskriftsartikel (refereegranskat)abstract
- The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.
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| 7. |
- Iniguez-de-la-Torre, I., et al.
(författare)
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Monte Carlo studies of the intrinsic time-domain response of nanoscale three-branch junctions
- 2012
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 111:8
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Tidskriftsartikel (refereegranskat)abstract
- We present a Monte Carlo time-domain study of nanostructured ballistic three-branch junctions (TBJs) excited by both step-function and Gaussian picosecond transients. Our TBJs were based on InGaAs 2-dimensional electron gas heterostructures and their geometry followed exactly the earlier experimental studies. Time-resolved, picosecond transients of both the central branch potential and the between-the-arms current demonstrate that the bandwidth of the intrinsic TBJ response reaches the THz frequency range, being mainly limited by the large-signal, intervalley scattering, when the carrier transport regime changes from ballistic to diffusive.
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| 8. |
- Krizsan, Sophie Julie, et al.
(författare)
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An in vitro evaluation of browser and grazer fermentation efficiency and microbiota using European moose spring and summer foods
- 2018
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 8, s. 4183-4196
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary morphological and physiological differences between browsers and grazers contribute to species- specific digestion efficiency of food resources. Rumen microbial community structure of browsers is supposedly adapted to characteristic nutrient composition of the diet source. If this assumption is correct, domesticated ruminants, or grazers, are poor model animals for assessing the nutritional value of food consumed by browsing game species. In this study, typical spring and summer foods of the European moose (Alces alces) were combined with rumen fluid collected from both dairy cows (Bos taurus) and from moose, with the aim of comparing fer- mentation efficiency and microbial community composition. The nutritional value of the food resources was characterized by chemical analysis and advanced in vitro measurements. The study also addressed whether or not feed evaluation based on in vitro techniques with cattle rumen fluid as inoculum could be a practical alternative when evaluating the nutritional value of plants consumed by wild browsers. Our re- sults suggest that the fermentation characteristics of moose spring and summer food are partly host- specific and related to the contribution of the bacterial phyla Firmicutes and Bacteriodetes to the rumen microbial community. Host- specific adaptations of the ruminal microbial community structure could be explained from the evolutionary adaptations related to feeding habitats and morphophysiological differences be- tween browsers and grazers. However, the observed overall differences in microbial community structure could not be related to ruminal digestion parameters measured in vitro. The in vitro evaluation of digestion efficiency reveals that equal amounts of methane were produced across all feed samples regardless of whether the ruminal fluid was from moose or dairy cow. The results of this study suggested that the nutri- tional value of browsers’ spring and summer food can be predicted using rumen fluid from domesticated grazers as inoculum in in vitro assessments of extent of digestion when excluding samples of the white water lily root, but not of fermentation characteristics as indicated by the proportions of individual fermentation fatty acids to the total of volatile fatty acids.
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| 9. |
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| 10. |
- Leonardi, Matilde, et al.
(författare)
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Integrating research into policy planning : MHADIE policy recommendations
- 2010
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Ingår i: Disability and Rehabilitation. - : Informa UK Limited. - 0963-8288 .- 1464-5165. ; 32:S1, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- MHADIE project (Measuring Health and Disability in Europe: Supporting policy development) aimed at developing realistic, evidence-based and effective national policies for persons with disabilities. A preliminary step towards this goal was the demonstration on the feasibility of employing the ICF in clinical, educational and statistical fields, which corresponds to the recognised need to enhance the European Union's capacity of analysis of disability, as highlighted in its Disability Action Plan 2006–2007. The ultimate outcome of the project is the production of 13 policy recommendations, dealing with statistics clinical and educational areas, and four general policy recommendations focusing on: (a) the need of coordinating and integrating disability conceptualisation at all policy levels and across sectors; (b) the need of conducing longitudinal cohort studies which include children aged 0–6; (c) the need of reviewing transportation policies in light of the requirements of persons with disabilities; (d) the need of reviewing all disability policies to emphasise and support the role of the family, which is a consistent and substantial environmental facilitator in the lives of persons with disabilities.
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| 11. |
- Mateos, J., et al.
(författare)
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Monte Carlo modelling of noise in advanced III–V HEMTs
- 2015
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Ingår i: Journal of Computational Electronics. - : Springer Science and Business Media LLC. - 1569-8025 .- 1572-8137. ; 14:1, s. 72-86
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Tidskriftsartikel (refereegranskat)abstract
- One of the main objectives of modern Microelectronicsis the fabrication of devices with increased cutofffrequency and decreased level of noise. At this moment, thebest devices for high-frequency, low-noise behavior areHighelectron mobility transistors (HEMTs) based on InGaAs andInAs channels. In this work, a complete analysis of ultrashort-gate HEMTs has been carried out by using a semiclassicalMonte Carlo simulator, paying special attention tothe noise performance. The validity of the model has beenchecked through the comparison of the simulated results withstatic, dynamic and noise measurements in real HEMTs. Inorder to reproduce the experimental results, we have includedin the model some important real effects such as degeneracy,surface charges, presence of dielectrics and contact parasitics.The cryogenic performance of the HEMTs has alsobeen analyzed. The influence of the parasitic resistances,width of the devices, value of the δ-doping and recess lengthhas been analyzed when scaling down the gate length of thetransistors to 50nm aiming at achieving higher cutoff frequenciesand better noise performance. The important effectof the impact ionization mechanisms and the consequent kinkeffect on the noise in both InGaAs and InAs based HEMTshave also been studied. Finally the advantages of the use of a double gate topology are quantified.
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| 12. |
- Rodilla, Helena, 1982, et al.
(författare)
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Cryogenic Performance of Low-Noise InP HEMTs: a Monte Carlo Study
- 2013
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Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 60:5, s. 1625-1631
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a study of the cryogenic performance of InP high electron mobility transistors (HEMTs) in the low-noise region by means of Monte Carlo simulations. A decrease of the contact resistances and an increase in the electron velocity in the channel together with enhanced channel electron confinement upon cooling of the device are observed, and considered to be the reason for the excellent low-noise behavior of cryogenic InP HEMTs. These findings are supported by a good agreement between simulated and experimental DC, RF, and noise figure data of a 130-nm gate length InP HEMT at 300 and 77 K. An increase of the transconductance g(m) and gate-to-source capacitance C-gs is observed when cooling from 300 to 77 K as a consequence of electron velocity increase and improved channel confinement.
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| 13. |
- Rodilla, Helena, 1982, et al.
(författare)
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Monte Carlo study of the dynamic performance of isolated-gate InAs/AlSb HEMTs
- 2011
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Ingår i: Proceedings of the 8th Spanish Conference on Electron Devices, CDE'2011, Palma de Mallorca; 8 February through 11 February. - 9781424478637
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Konferensbidrag (refereegranskat)abstract
- In this work, by means of Monte Carlo simulations, the static and dynamic performance of InAs/AlSb HEMTs at low drain voltages is analyzed. A very good agreement between experimental and simulation results has been obtained not only for the static behavior, but also for small signal equivalent circuit parameters like C gs , C gd , f t and f c . Problems arise when trying to reproduce the values of g d and C ds due to the experimental frequency dispersion, leading also to discrepancies in the values obtained for the intrinsic g m and also f max . © 2011 IEEE.
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| 14. |
- Rodilla, Helena, 1982, et al.
(författare)
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Monte Carlo study of the noise performance of isolated-gate InAs/AlSb HEMTs
- 2012
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 27:1, s. 015008-
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the extrinsic dynamic behavior and noise performance of a 225 nm isolated-gateInAs/AlSb high electron mobility transistor (HEMT) have been studied by means of MonteCarlo simulations. A very good agreement with experimental results has been achieved for fT .Discrepancies between experimental and simulated f max have been observed and attributed tothe experimental frequency dispersion of gd and Cds. The simulations of the intrinsic andextrinsic noise parameters indicate an excellent performance for this device (Fmin = 0.3 dB at10 GHz) even if we confirm that the presence of the native oxide under the gate induces asignificant decrease in fT and f max of around 20%, together with an increase of noise figureand noise resistance.
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| 15. |
- Tartaro, Giuseppe, et al.
(författare)
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Microemulsion Microstructure(s) : A Tutorial Review
- 2020
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 10:9, s. 1657-1657
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Tidskriftsartikel (refereegranskat)abstract
- Microemulsions are thermodynamically stable, transparent, isotropic single-phase mixtures of two immiscible liquids stabilized by surfactants (and possibly other compounds). The assortment of very different microstructures behind such a univocal macroscopic definition is presented together with the experimental approaches to their determination. This tutorial review includes a necessary overview of the microemulsion phase behavior including the effect of temperature and salinity and of the features of living polymerlike micelles and living networks. Once these key learning points have been acquired, the different theoretical models proposed to rationalize the microemulsion microstructures are reviewed. The focus is on the use of these models as a rationale for the formulation of microemulsions with suitable features. Finally, current achievements and challenges of the use of microemulsions are reviewed.
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| 16. |
- Vasallo, Beatriz G., et al.
(författare)
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Kink effect and noise performance in isolated-gate InAs/AlSb high electron mobility transistors
- 2012
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 27:6, s. Article Number: 065018-
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Tidskriftsartikel (refereegranskat)abstract
- The kink effect can spoil the otherwise excellent low noise performance of InAs/AlSb high electron mobility transistors. It has its origin in the pile-up of holes (generated by impact ionization) taking place mainly at the drain side of the buffer, which leads to a reduction of the gate-induced channel depletion and results in a drain current enhancement. Our results indicate that the generation of holes by impact ionization and their further recombination lead to fluctuations in the charge of the hole pile-up, which provoke an important increase in the drain current noise, even when the kink effect is hardly perceptible in the output characteristics.
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| 17. |
- Vasallo, Beatriz G., et al.
(författare)
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Monte Carlo study of impact ionization and hole transport in InAs HEMTs with isolated gate
- 2011
-
Ingår i: Proceedings of the 8th Spanish Conference on Electron Devices, CDE'2011, Palma de Mallorca; 8 February 2011 through 11 February. - 9781424478637
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Konferensbidrag (refereegranskat)abstract
- We present a physical analysis of the kink effect in InAs/AlSb High Electron Mobility Transistors (HEMTs) performed by means of a semiclassical 2D ensemble Monte Carlo simulator. InAs-channel HEMTs are very susceptible to suffer from impact ionization phenomena due to the small bandgap of InAs. These processes, jointly with the associated hole transport, are at the origin of the kink effect. When the drain-to-source voltage is high enough for the onset of impact ionization, generated holes tend to accumulate at the gate-drain side of the buffer because of the valence-band energy barrier present between the buffer and the channel. Due to this pile up of positive charge the channel is further opened and the drain current increases, leading to the kink in the I-V characteristics. © 2011 IEEE.
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