| 1. |
- Borgmästars, Emmy, et al.
(författare)
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Comparison of Skimmed Milk and Lanthanum Flocculation for Concentration of Pathogenic Viruses in Water
- 2021
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Ingår i: Food and Environmnetal Virology. - : Springer. - 1867-0334 .- 1867-0342. ; 13:3, s. 380-389
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Tidskriftsartikel (refereegranskat)abstract
- Concentration of viruses in water is necessary for detection and quantification of the viruses present, in order to evaluate microbiological barriers in water treatment plants and detect pathogenic viruses during waterborne outbreaks, but there is currently no standardised procedure. In this study, we implemented a previously described fast and simple lanthanum-based protocol for concentration of norovirus genogroup I (GI), genogroup II (GII) and hepatitis A virus (HAV) in drinking and surface water. We compared the results with those of a widely used skimmed milk flocculation method, followed by nucleic acid extraction and RT-qPCR detection. Three seeding levels, with intended concentrations 5 × 103, 5 × 104 and 5 × 105 genome copies/10 L, were added to drinking water or surface water. All seed levels were detected with both flocculation methods. Samples extracted with skimmed milk flocculation had on average 1.82, 1.86 and 1.38 times higher measured concentration of norovirus GI, GII and HAV, respectively, than those extracted with lanthanum flocculation, across all seeding levels and water types tested. Mengovirus was used as a positive process control. Mengovirus recovery was higher for skimmed milk (40.7% in drinking water, 26.0% in surface water) than for lanthanum flocculation (24.4% in drinking water, 9.7% in surface water). Together, this indicates that skimmed milk flocculation provides higher viral recovery than lanthanum flocculation. However, lanthanum-based flocculation can be performed much faster than skimmed milk flocculation (1.5 h versus 16 h flocculation time) and thus could be a good alternative for rapid monitoring of viruses in water.
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| 2. |
- Borgmästars, Emmy, et al.
(författare)
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Improved Detection of Norovirus and Hepatitis A Virus in Surface Water by Applying Pre-PCR Processing
- 2017
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Ingår i: Food and Environmental Virology. - : Springer Science and Business Media LLC. - 1867-0334 .- 1867-0342. ; 9:4, s. 395-405
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Tidskriftsartikel (refereegranskat)abstract
- Quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) detection of waterborne RNA viruses generally requires concentration of large water volumes due to low virus levels. A common approach is to use dead-end ultrafiltration followed by precipitation with polyethylene glycol. However, this procedure often leads to the co-concentration of PCR inhibitors that impairs the limit of detection and causes false-negative results. Here, we applied the concept of pre-PCR processing to optimize RT-qPCR detection of norovirus genogroup I (GI), genogroup II (GII), and hepatitis A virus (HAV) in challenging water matrices. The RT-qPCR assay was improved by screening for an inhibitor-tolerant master mix and modifying the primers with twisted intercalating nucleic acid molecules. Additionally, a modified protocol based on chaotropic lysis buffer and magnetic silica bead nucleic acid extraction was developed for complex water matrices. A validation of the modified extraction protocol on surface and drinking waters was performed. At least a 26-fold improvement was seen in the most complex surface water studied. The modified protocol resulted in average recoveries of 33, 13, 8, and 4% for mengovirus, norovirus GI, GII, and HAV, respectively. The modified protocol also improved the limit of detection for norovirus GI and HAV. RT-qPCR inhibition with Cq shifts of 1.6, 2.8, and 3.5 for norovirus GI, GII, and HAV, respectively, obtained for the standard nucleic acid extraction were completely eliminated by the modified protocol. The standard nucleic acid extraction method worked well on drinking water with no RT-qPCR inhibition observed and average recoveries of 80, 124, 89, and 32% for mengovirus, norovirus GI, GII, and HAV, respectively.
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| 3. |
- Buckel, Alexander, et al.
(författare)
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Importance of First Cycle Conditions on the Electrochemical Performance of Hard Carbon and Prussian White Based Sodium-Ion Batteries Using Fire Resistant, Fluorine-Free Electrolyte
- 2024
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Ingår i: Batteries & Supercaps. - : John Wiley & Sons. - 2566-6223. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Electrolytes based on sodium bis(oxolato)borate (NaBOB) in organophosphates (trimethyl phosphate and triethyl phosphate (TEP)) have shown promise in sodium-ion batteries when compared to conventional electrolytes in that they are fire resistant, fluorine-free and are of lower toxicity. However, these electrolytes tend to exhibit low initial Coulombic efficiency and high overpotentials. We have here demonstrated that NaBOB in TEP can be used in cells with near-commercial capacity loadings. Furthermore, we have shown that formation cycle conditions have a significant positive effect on the cell performance in these higher mass loading cells, and that modification of the formation cycle conditions can be used to increase the capacity retention, lower the overpotentials, and as such increase the rate capability. The viability of optimized formation protocols was also demonstrated in scaled up prototype cells. Formation cycling: In this article we present a solution to the poor cyclability of non-flammable sodium bis(oxolato)borate (NaBOB) in triethyl phosphate (TEP) electrolyte. By developing a formation cycle specific to this NaBOB in TEP electrolyte, we are able to cycle a 4.5 Ah full cell with high mass loading electrodes to beyond 900 cycles before reaching 80 % state of health.image
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| 4. |
- Enkirch, Theresa, et al.
(författare)
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Hepatitis A outbreak linked to imported frozen strawberries by sequencing, Sweden and Austria, June to September 2018
- 2018
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Ingår i: Eurosurveillance. - : European Centre for Disease Prevention and Control. - 1025-496X .- 1560-7917. ; 23:41
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Tidskriftsartikel (refereegranskat)abstract
- Between June-September 2018, 20 hepatitis A cases were notified in six counties in Sweden. Combined epidemiological and microbiological investigations identified imported frozen strawberries produced in Poland as the source of the outbreak. Sequence analysis confirmed the outbreak strain IB in the strawberries with 100 % identity and the respective batch was withdrawn. Sharing the sequence information internationally led to the identification of 14 additional cases in Austria, linked to strawberries from the same producer.
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| 5. |
- Eriksson, Ronnie, et al.
(författare)
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Multiplex and quantifiable detection of nucleic acid from pathogenic fungi using padlock probes, generic real time PCR and specific suspension array readout
- 2009
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Ingår i: Journal of Microbiological Methods. - : Elsevier BV. - 0167-7012 .- 1872-8359. ; 78:2, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- A new concept for multiplex detection and quantification of microbes is here demonstrated on a range of infectious fungal species. Padlock probe methodology in conjunction with qPCR and Luminex technology was used for simultaneous detection of ten fungal species in one single experiment. By combining the multiplexing properties of padlock probes and Luminex detection with the well established quantitative characteristics of qPCR, quantitative microbe detection was done in 10-plex mode. A padlock probe is an oligonucleotide that via a ligation reaction forms circular DNA when hybridizing to specific target DNA. The region of the padlock probe that does not participate in target DNA hybridization contains generic primer sequences for amplification and a tag sequence for Luminex detection. This was the fundament for well performing multiplexing. Circularized padlock probes were initially amplified by rolling circle amplification (RCA), followed by a SybrGreen real time PCR which allowed an additive quantitative assessment of target DNA in the sample. Detection and quantification of amplified padlock probes were then done on color coded Luminex microspheres carrying anti-tag sequences. A novel technique, using labeled oligonucleotides to prevent reannealing of amplimers by covering the flanks of the address sequence, improved the signal to noise ratio in the detection step considerably. The method correctly detected fungi in a variety of clinical samples and offered quantitative information on fungal nucleic acid.
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| 6. |
- Horak, Josef, et al.
(författare)
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Recombinant Spider Silk as Mediator for One-Step, Chemical-Free Surface Biofunctionalization
- 2018
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 28:21
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Tidskriftsartikel (refereegranskat)abstract
- A unique strategy for effective, versatile, and facile surface biofunctionalization employing a recombinant spider silk protein genetically functionalized with the antibody-binding Z domain (Z-4RepCT) is reported. It is demonstrated that Z-silk can be applied to a variety of materials and platform designs as a truly one-step and chemical-free surface modification that site specifically captures antibodies while simultaneously reducing nonspecific adsorption. As a model surface, SiO2 is used to optimize and characterize Z-silk performance compared to the Z domain immobilized by a standard silanization method. First, Z-silk adsorption is investigated and verified its biofunctionality in a long-term stability experiment. To assess the binding capacity and protein-protein interaction stability of Z-silk, the coating is used to capture human antibodies in various assay formats. An eightfold higher binding capacity and 40-fold lower detection limit are obtained in the immunofluorescence assay, and the complex stability of captured antibodies is shown to be improved by a factor of 20. Applicability of Z-silk to functionalize microfluidic devices is demonstrated by antibody detection in an electrokinetic microcapillary biosensor. To test Z-silk for biomarker applications, real-time detection and quantification of human immunoglobulin G are performed in a plasma sample and C1q capture from human serum using an anti-C1q antibody.
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| 7. |
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| 8. |
- Håkansson, Peter, 1979-
(författare)
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The United Nations Reformed : Responsibility, Protection and the Standing of States
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study is about reform of the United Nations. The study does not address reform proposals that set out to change the organizational structure of the UN, but focuses on initiatives that affect the normative basis of the international society that the United Nations and the UN Charter enable and sustain. Empirically, the study focuses on the international principle responsibility 10 prolecl, which prescribes that states have an individual and collective responsibility to protect against human rights violations. It is argued that the responsibility to protect and the Security Council's increased attention to protection of civilians in armed conflicts are politically and legally significant developments that challenge the pluralist international order that was instituted through the establishment of the UN in 1945. Both the responsibility to proteet and the protection of civilians are based on an understanding of statehood and international society that in the study is referred to as anti-pluralist. The results of the study show that the contemporary notion of protection once again brings into international political discourse the idea that states and political communities, in order to enjoy legal autonomy and a right to non-intervention, must abide by universally applicable standards of state hood. The results also show that the idea of protection is based on a progressivist philosophy that leads to a differentiation of states.
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| 9. |
- Jansson, Linda, et al.
(författare)
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Evaluation and modification of lanthanum-based flocculation for isolation of bacteria from water samples
- 2018
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Ingår i: Biotechnology Reports. - : Elsevier BV. - 2215-017X. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Molecular detection of pathogenic microorganisms in drinking and natural water is often challenged by low concentrations of the sought-after agents. Convenient methods to concentrate bacteria from water samples ranging from 1-10 L are highly warranted. Here we account for the evaluation of a lanthanum-based flocculation method to concentrate bacteria from water samples, applying four different bacterial species in tap water as well as river water. Our results show that the success of lanthanum-based flocculation is determined by both the bacterial species and the nature of the water sample. For tap water, satisfying flocculation efficiencies (above 60 %) were only reached for autoclaved water samples. However, the performance of the lanthanum-based flocculation method for non-autoclaved water was markedly improved by the addition of 20 mM bicarbonate to increase alkalinity. Our modified flocculation protocol may be applied as an alternative concentration method for bacteria in water samples of one liter or more.
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| 10. |
- Jansson, Linda, et al.
(författare)
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Impact of swab material on microbial surface sampling
- 2020
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Ingår i: Journal of Microbiological Methods. - : Elsevier BV. - 0167-7012. ; 176
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Tidskriftsartikel (refereegranskat)abstract
- Efficient microbial sampling from surfaces for subsequent detection and quantification is crucial in fields such as food safety and hygiene monitoring. Cotton swabs are traditionally used for sample collection, but today there are numerous swabs of alternative material and different sizes available. Recovery efficiencies of swabs for different applications have been compared in several studies. However, the results are often contradictory. We have compared 15 different swabs made of cotton (n = 5), flocked nylon (n = 3) and foam (n = 7), for sampling of Listeria monocytogenes and mengovirus on small (4 cm2) and large (100 cm2) areas of window glass, ridged plastic and absorbing wood. Molecular quantification methods (qPCR and RT-qPCR) were applied, and all sampling and sample processing were standardized. Specific swabs gave higher DNA/RNA yields than others, depending on both the surface characteristics and the collected target. The highest DNA yields were achieved by applying Selefa or Puritan cotton swabs for Listeria sampling on 4 cm2 areas of window glass and ridged plastic. Certain foam swabs (Critical swab with medium head and Macrofoam) gave the highest yields when sampling Listeria on 4 cm2 areas of wood and on 100 cm2 areas of ridged plastic and wood. Most foam swabs, and especially Sigma Virocult, were advantageous for virus sampling, regardless of surface. Nylon-flocked swabs showed poor recovery regardless of surface characteristics. The recovery varied substantially between swabs made of the same material, suggesting that a single swab may not be representative for a certain swab material.
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