| 1. |
- Benselfelt, Tobias, et al.
(författare)
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Explaining the Exceptional Wet Integrity of Transparent Cellulose Nanofibril Films in the Presence of Multivalent Ions-Suitable Substrates for Biointerfaces
- 2019
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Ingår i: Advanced Materials Interfaces. - : WILEY. - 2196-7350. ; 6:13
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose nanofibrils (CNFs) assemble into water-resilient materials in the presence of multivalent counter-ions. The essential mechanisms behind these assemblies are ion-ion correlation and specific ion effects. A network model shows that the interfibril attraction indirectly influences the wet modulus by a fourth power relationship to the solidity of the network (E-w proportional to phi(4)). Ions that induce both ion-ion correlation and specific ion effects significantly reduce the swelling of the films, and due to the nonlinear relationship dramatically increase the wet modulus. Herein, this network model is used to explain the elastoplastic behavior of wet films of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized, carboxymethylated, and phosphorylated CNFs in the presence of different counter-ions. The main findings are that the aspect ratio of the CNFs influences the ductility of the assemblies, that the bivalency of phosphorylate ligands probably limits the formation of interfibril complexes with divalent ions, and that a higher charge density increases the friction between fibrils by increasing the short-range attraction from ion-ion correlation and specific ion effects. These findings can be used to rationally design CNF materials for a variety of applications where wet strength, ductility, and transparency are important, such as biomaterials or substrates for bioelectronics.
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| 2. |
- Bergqvist, Joakim, et al.
(författare)
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Detection and Isolation of Sindbis Virus from Mosquitoes Captured During an Outbreak in Sweden, 2013
- 2015
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Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:2, s. 133-140
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Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne alphaviruses have the potential to cause large outbreaks throughout the world. Here we investigated the causative agent of an unexpected Sindbis virus (SINV) outbreak during August-September, 2013, in a previously nonendemic region of Sweden. Mosquitoes were collected using carbon dioxide-baited CDC traps at locations close to human cases. The mosquitoes were initially screened as large pools by SINV-specific quantitative RT-PCR, and the SINV-positive mosquitoes were species determined by single-nucleotide polymorphism (SNP) analysis, followed by sequencing the barcoding region of the cytochrome oxidase I gene. The proportion of the collected mosquitoes was determined by a metabarcoding strategy. By using novel strategies for PCR screening and genetic typing, a new SINV strain, Lovanger, was isolated from a pool of 1600 mosquitoes composed of Culex, Culiseta, and Aedes mosquitoes as determined by metabarcoding. The SINV-positive mosquito Culiseta morsitans was identified by SNP analysis and sequencing. After whole-genome sequencing and phylogenetic analysis, the SINV Lovanger isolate was shown to be most closely similar to recent Finnish SINV isolates. In conclusion, within a few weeks, we were able to detect and isolate a novel SINV strain and identify the mosquito vector during a sudden SINV outbreak.
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| 3. |
- de Graaf, Sebastian Erik, 1986, et al.
(författare)
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Direct Identification of Dilute Surface Spins on Al2 O3: Origin of Flux Noise in Quantum Circuits
- 2017
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 118:5, s. 057703-
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Tidskriftsartikel (refereegranskat)abstract
- An on-chip electron spin resonance technique is applied to reveal the nature and origin of surface spins on Al2O3. We measure a spin density of 2.2×1017 spins/m2, attributed to physisorbed atomic hydrogen and S=1/2 electron spin states on the surface. This is direct evidence for the nature of spins responsible for flux noise in quantum circuits, which has been an issue of interest for several decades. Our findings open up a new approach to the identification and controlled reduction of paramagnetic sources of noise and decoherence in superconducting quantum devices.
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| 4. |
- de Graaf, Sebastian Erik, 1986, et al.
(författare)
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Suppression of low-frequency charge noise in superconducting resonators by surface spin desorption
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Noise and decoherence due to spurious two-level systems located at material interfaces are long-standing issues for solid-state quantum devices. Efforts to mitigate the effects of two-level systems have been hampered by a lack of knowledge about their chemical and physical nature. Here, by combining dielectric loss, frequency noise and on-chip electron spin resonance measurements in superconducting resonators, we demonstrate that desorption of surface spins is accompanied by an almost tenfold reduction in the charge-induced frequency noise in the resonators. These measurements provide experimental evid ence that simultaneously reveals the chemical signatures of adsorbed magnetic moments and highlights their role in generating charge noise in solid-state quantum devices.
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| 5. |
- Geaney, S., et al.
(författare)
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Near-Field Scanning Microwave Microscopy in the Single Photon Regime
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The microwave properties of nano-scale structures are important in a wide variety of applications in quantum technology. Here we describe a low-power cryogenic near-field scanning microwave microscope (NSMM) which maintains nano-scale dielectric contrast down to the single microwave photon regime, up to 109 times lower power than in typical NSMMs. We discuss the remaining challenges towards developing nano-scale NSMM for quantum coherent interaction with two-level systems as an enabling tool for the development of quantum technologies in the microwave regime.
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| 6. |
- Lilja, Tobias, et al.
(författare)
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Species identification of Swedish mosquitoes through DNA metabarcoding
- 2017
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Ingår i: Journal of the European Mosquito Control Association. ; 35, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- DNA-barcoding utilises a fragment of the mitochondrial cytochrome oxidase subunit 1 (COI) gene to identify most animal species. Using next generation sequencing (NGS), this method can be further developed into metabarcoding processes that allow the simultaneous identification of several species from a mixed sample. We created a database of COI sequences of 27 mosquito species collected in Sweden, and combined our data with 27 additional sequences from GenBank to cover the taxa recently documented in Sweden and to include possible invasive taxa. Comparisons show that COI metabarcoding reliably identifies 41 of 54 species and the remainder to species group. Using three independent primer pairs along the COI gene, we further developed this barcoding approach to simultaneously identify Swedish mosquitoes in communities using NGS and quantify relative abundance of each mosquito species in the sample, using bioinformatics methods. We tested the accuracy of the metabarcoding method using communities assembled from morphologically identified mosquitoes, revealing 80% positive identification rate and the estimates of population structure which reflects the input sample. We conclude that metabarcoding is useful as a high throughput identification technique and for the quantification of species.
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| 7. |
- Lindström, Tobias, 1992-
(författare)
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Ett huvudlöst förslag : angående den tredje individen i grav 7 från Ire
- 2019
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Ingår i: Fornvännen. - Solna : Kungl. Vitterhets Historie och Antikvitets Akademien. - 0015-7813 .- 1404-9430. ; 114:4, s. 220-228
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Tidskriftsartikel (refereegranskat)abstract
- In the current exhibition on Swedish prehistory at the Swedish History Museum, visitors can observe an extraordinarily emotive Stone Age grave containing the skeletons of a man and a small child. However, the grave was interpreted by the excavators as containing three skeletons. The third skeleton has for some reason been omitted from the exhibition altogether. At the time of the excavation the omitted skeleton was found without the cranium and was placed slightly below the bent legs of the other two skeletons. I argue that the three skeletons, although perhaps representing two burial episodes, should be regarded as relating to one another in a grave assemblage. Instead of presenting the cropped grave assemblage in order to discuss family norms in the past, as is the case in the current exhibition at the museum, we might instead exhibit the assemblage in its entirety as a means to discuss temporal and cultural variations in the attitudes towards "proper" graves, the body and the sacred.
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| 8. |
- Magdalinou, N. K., et al.
(författare)
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Identification of candidate cerebrospinal fluid biomarkers in parkinsonism using quantitative proteomics
- 2017
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Ingår i: Parkinsonism & Related Disorders. - : Elsevier BV. - 1353-8020 .- 1873-5126. ; 37, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Neurodegenerative parkinsonian syndromes have significant clinical and pathological overlap, making early diagnosis difficult. Cerebrospinal fluid (CSF) biomarkers may aid the differentiation of these disorders, but other than a-synuclein and neurofilament light chain protein, which have limited diagnostic power, specific protein biomarkers remain elusive. Objectives: To study disease mechanisms and identify possible CSF diagnostic biomarkers through discovery proteomics, which discriminate parkinsonian syndromes from healthy controls. Methods: CSF was collected consecutively from 134 participants; Parkinson's disease (n = 26), atypical parkinsonian syndromes (n = 78, including progressive supranuclear palsy (n = 36), multiple system atrophy (n = 28), corticobasal syndrome (n = 14)), and elderly healthy controls (n = 30). Participants were divided into a discovery and a validation set for analysis. The samples were subjected to tryptic digestion, followed by liquid chromatography-mass spectrometry analysis for identification and relative quantification by isobaric labelling. Candidate protein biomarkers were identified based on the relative abundances of the identified tryptic peptides. Their predictive performance was evaluated by analysis of the validation set. Results: 79 tryptic peptides, derived from 26 proteins were found to differ significantly between atypical parkinsonism patients and controls. They included acute phase/inflammatory markers and neuronal/synaptic markers, which were respectively increased or decreased in atypical parkinsonism, while their levels in PD subjects were intermediate between controls and atypical parkinsonism. Conclusion: Using an unbiased proteomic approach, proteins were identified that were able to differentiate atypical parkinsonian syndrome patients from healthy controls. Our study indicates that markers that may reflect neuronal function and/or plasticity, such as the amyloid precursor protein, and inflammatory markers may hold future promise as candidate biomarkers in parkinsonism. (C) 2017 Published by Elsevier Ltd.
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| 9. |
- Rydén Ahlgren, Åsa, et al.
(författare)
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Profound Increase in Longitudinal Displacements of the Porcine Carotid Artery Wall Can Take Place Independently of Wall Shear Stress: A Continuation Report.
- 2015
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier BV. - 0301-5629. ; 41:5, s. 1342-1353
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms underlying longitudinal displacements of the arterial wall, that is, displacements of the wall layers along the artery, and the resulting intramural shear strain remain largely unknown. We have already found that these displacements undergo profound changes in response to catecholamines. Wall shear stress, closely related to wall shear rate, represents the viscous drag exerted on the vessel wall by flowing blood. The aim of the work described here was to study possible relations between the wall shear rate and the longitudinal displacements. We investigated the carotid arteries of five anesthetized pigs in different hemodynamic situations using in-house developed non-invasive ultrasound techniques. The study protocol included administration of epinephrine, norepinephrine and β-blockade (metoprolol). No significant correlation between longitudinal displacement of the intima-media complex and wall shear rate was found. This result suggests that one or multiple pulsatile forces other than wall shear stress are also working along arteries, strongly influencing arterial wall behavior.
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