| 1. |
- Berglund, Björn, et al.
(författare)
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Efficient removal of antibiotics in surface-flow constructed wetlands, with no observed impact on antibiotic resistance genes
- 2014
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Ingår i: Science of the Total Environment. - Amsterdam : Elsevier. - 0048-9697 .- 1879-1026. ; 476-477, s. 29-37
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Tidskriftsartikel (refereegranskat)abstract
- Recently, there have been growing concerns about pharmaceuticals including antibiotics as environmental contaminants. Antibiotics of concentrations commonly encountered in wastewater have been suggested to affect bacterial population dynamics and to promote dissemination of antibiotic resistance. Conventional wastewater treatment processes do not always adequately remove pharmaceuticals causing environmental dissemination of low levels of these compounds. Using constructed wetlands as an additional treatment step after sewage treatment plants have been proposed as a cheap alternative to increase reduction of wastewater contaminants, however this means that the natural microbial community of the wetlands becomes exposed to elevated levels of antibiotics. In this study, experimental surface-flow wetlands in Sweden were continuously exposed to antibiotics of concentrations commonly encountered in wastewater. The aim was to assess the antibiotic removal efficiency of constructed wetlands and to evaluate the impact of low levels of antibiotics on bacterial diversity, resistance development and expression in the wetland bacterial community. Antibiotic concentrations were measured using liquid chromatography-mass spectrometry and the effect on the bacterial diversity was assessed with 16S rRNA-based denaturing gradient gel electrophoresis. Real-time PCR was used to detect and quantify antibiotic resistance genes and integrons in the wetlands, during and after the exposure period. The results indicated that the antibiotic removal efficiency of constructed wetlands was comparable to conventional wastewater treatment schemes. Furthermore, short-term treatment of the constructed wetlands with environmentally relevant concentrations (i.e. 100-2000 ng x 1(-1)) of antibiotics did not significantly affect resistance gene concentrations, suggesting that surface-flow constructed wetlands are well-suited for wastewater treatment purposes. (c) 2014 Elsevier B.V. All rights reserved.
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| 2. |
- Devi, Chandni, et al.
(författare)
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High sodium ionic conductivity in PEO/PVP solid polymer electrolytes with InAs nanowire fillers
- 2021
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Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Solid-state sodium ion batteries are frequently referred to as the most promising technology for next-generation energy storage applications. However, developing a suitable solid electrolyte with high ionic conductivity, excellent electrolyte–electrode interfaces, and a wide electrochemical stability window, remains a major challenge. Although solid-polymer electrolytes have attracted great interest due to their low cost, low density and very good processability, they generally have significantly lower ionic conductivity and poor mechanical strength. Here, we report on the development of a low-cost composite solid polymer electrolyte comprised of poly(ethylene oxide), poly(vinylpyrrolidone) and sodium hexafluorophosphate, mixed with indium arsenide nanowires. We show that the addition of 1.0% by weight of indium arsenide nanowires increases the sodium ion conductivity in the polymer to 1.50 × 10−4 Scm−1 at 40 °C. In order to explain this remarkable characteristic, we propose a new transport model in which sodium ions hop between close-spaced defect sites present on the surface of the nanowires, forming an effective complex conductive percolation network. Our work represents a significant advance in the development of novel solid polymer electrolytes with embedded engineered ultrafast 1D percolation networks for near-future generations of low-cost, high-performance batteries with excellent energy storage capabilities. © 2021, The Author(s).
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| 3. |
- Burestedt, E., et al.
(författare)
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Optimisation and validation of an automated solid phase extraction technique coupled on-line to enzyme-based biosensor detection for the determination of phenolic compounds in surface water samples
- 1995
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Ingår i: Chromatographia. - Heidelberg : Springer Berlin/Heidelberg. - 0009-5893 .- 1612-1112. ; 41:3-4, s. 207-215
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Tidskriftsartikel (refereegranskat)abstract
- A fully integrated screening system for phenolic compounds was developed incorporating on-line solid phase extraction, fractionation and biosensor detection. Two different types of biosensors, solid graphite and carbon paste electrodes incorporating the enzyme tyrosinase, were compared and used in the screening system. Interfacing of the solid phase extraction and fractionation with the biosensor detection was given special attention since the biosensors were not compatible with the organic modifier used for desorption of phenols from the solid phase extraction step. The system was validated with conventional analytical techniques. Surface water samples from the Ebro river were spiked with 1,10, and 25μg L−1 of catechol, phenol,p-cresol, respectively. Three out of seven samples were spiked and the correct samples were identified, containing phenols equivalent to the spiked concentrations. © 1995 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH.
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| 4. |
- Deshmukh, Shradha, et al.
(författare)
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Explainable quantum clustering method to model medical data
- 2023
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Ingår i: Knowledge-Based Systems. - Amsterdam : Elsevier. - 0950-7051 .- 1872-7409. ; 267, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- Medical experts are often skeptical of data-driven models due to the lack of their explainability. Several experimental studies commence with wide-ranging unsupervised learning and precisely with clustering to obtain existing patterns without prior knowledge of newly acquired data. Explainable Artificial Intelligence (XAI) increases the trust between virtual assistance by Machine Learning models and medical experts. Awareness about how data is analyzed and what factors are considered during the decision-making process can be confidently answered with the help of XAI. In this paper, we introduce an improved hybrid classical-quantum clustering (improved qk-means algorithm) approach with the additional explainable method. The proposed model uses learning strategies such as the Local Interpretable Model-agnostic Explanations (LIME) method and improved quantum k-means (qk-means) algorithm to diagnose abnormal activities based on breast cancer images and Knee Magnetic Resonance Imaging (MRI) datasets to generate an explanation of the predictions. Compared with existing algorithms, the clustering accuracy of the generated clusters increases trust in the model-generated explanations. In practice, the experiment uses 600 breast cancer (BC) patient records with seven features and 510 knee MRI records with five features. The result shows that the improved hybrid approach outperforms the classical one in the BC and Knee MRI datasets. © 2023 Elsevier B.V.
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| 5. |
- Dimkovski, Zlate, et al.
(författare)
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Interference Measurements of Deposits on Cylinder Liner Surfaces
- 2011
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Ingår i: Wear. - Amsterdam : Elsevier. - 0043-1648 .- 1873-2577. ; 270:3-4, s. 247-251
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of deposits in the honing grooves of the cylinder liner surfaces of internal combustion engines is undesirable as they seal the grooves (reducing their oil retention capability) and increase engine's oil consumption. As part of a long-term programme of truck engine development, after different running times and under similar conditions of load, engine speed and lubrication, a number of grey iron cylinder liners were axially sectioned, measured, inspected and a presence of deposits was discovered. These deposits were characterised in order to gain knowledge about their origin and quantities. The X-ray energy dispersive analysis revealed elements stemming from the oil/fuel (C, O and S), from the detergent (Ca and Mg), from the anti-wear additive (Zn and P), and from some contaminants (K and Si). Higher concentration of S and Ca were mostly found in the honing grooves covered with deposits suggesting a domination of the detergent additive. Deposit thickness measurements obtained by a white light interferometer revealed patchy deposit topographies concentrated at the top region reducing towards the bottom of the liner which was also confirmed by scanning electron microscope measurements. Despite the limitations of the interferometer, it has been shown that the interference measurements are sufficiently reliable for a quick and objective quantification of the overall deposit accumulation.
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| 6. |
- Elgh-Dalgren, Kristin, et al.
(författare)
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Anaerobic bioremediation of a soil with mixed contaminants : Explosives degradation and influence on heavy metal distribution, monitored as changes in concentration and toxicity
- 2009
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Ingår i: Water, Air and Soil Pollution. - Dordrecht : Springer Netherlands. - 0049-6979 .- 1573-2932. ; 202:1-4, s. 301-313
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Tidskriftsartikel (refereegranskat)abstract
- Two soils with explosives and metals were evaluated for the degradation efficiency of explosives by native microorganisms under anaerobic conditions. The commercially available method Daramend®, amended with zero-valent iron (ZVI), was compared with a horse-manure amended compost and a treatment with ZVI alone. In a moderately contaminated soil, Daramend® and ZVI treatment gave significantly higher removal rates compared to compost and control treatments (Tukey’s test, P<0.05). The largest overall decrease in ecotoxicity, measured with bioluminescent bacteria (Vibrio fischeri), was achieved with ZVI-treatment. In a more contaminated soil no degradation of contaminants and no decline in soil toxicity could be distinguished after the same time period. Problems with establishment of anaerobic conditions during parts of the remediation process and low microbial activity due to acute toxicity of contaminants are plausible explanations. Redistribution that could potentially lead to mobilization of the co-contaminant Pb was not observed in either of the soils during the biological treatments.
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| 7. |
- Green, David C., 1987-, et al.
(författare)
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Dichroic Calcite Reveals the Pathway from Additive Binding to Occlusion
- 2021
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Ingår i: Crystal Growth & Design. - Washington, DC : American Chemical Society (ACS). - 1528-7483 .- 1528-7505. ; 21:7, s. 3746-3755
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Tidskriftsartikel (refereegranskat)abstract
- Organic additives play key roles in controlling the precipitation of calcium carbonate in the environment, industry, and biology, where they can direct polymorphism, alter crystal morphologies, and sometimes even become occluded, modifying bulk properties. However, significant questions remain regarding the pathway from adsorption on crystal surfaces to occlusion. Here, the optical properties of calcite crystals grown in the presence of the dye Congo red are used to characterize the organization of the additives within the crystal. Complemented by the analysis of surface adsorption through in situ atomic force microscopy (AFM), molecular simulations, and changes in crystal morphologies, we show that the occluded dye molecules are randomly oriented under fast growth conditions, but that slow growth engenders ordering of the dye within islands, whose orientation is determined by the dye/terrace interaction free energy. The islands are subsequently overgrown such that their internal structure is preserved. These results reveal that the occlusion of organic macromolecules into calcite can be understood by thermodynamics operating at the adsorption stage. This new insight will ultimately enable the design of additives to give specific material properties.
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| 8. |
- Larsson, Marita, et al.
(författare)
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Transient isotachophoresis for sensitivity enhancement in capillary electrophoresis-mass spectrometry for peptide analysis
- 2000
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Ingår i: Electrophoresis. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 0173-0835 .- 1522-2683. ; 21:14, s. 2859-2865
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Tidskriftsartikel (refereegranskat)abstract
- Transient isotachophoresic (ITP) focusing was used for the on-line analysis of peptides by capillary zone electrophoresis-mass spectrometry (CZE-MS), allowing injection volumes of up to 0.9 microL. A sheath liquid electrospray interface was used with a single quadrupole mass analyzer. First, the technique was applied to the qualitative analysis of a tryptic digest of cytochrome c, resulting in low-background, high-quality spectra. Second, the linear range was investigated by selected ion monitoring (SIM) for a peptidomimetic direct thrombin inhibitor melagatran (Mr 429.5) and two endogenous peptides, substance P (Mr 1348) and calcitonin gene-related peptide (alpha-CGRP; Mr 3806).
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| 9. |
- Lutz, Mareike, 1967-, et al.
(författare)
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Applying hollow fibres for separating free and bound label in continuous-flow immunochemical detection
- 1996
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Ingår i: Journal of Chromatography A. - Amsterdam : Elsevier B.V. - 0021-9673 .- 1873-3778. ; 755:2, s. 179-187
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Tidskriftsartikel (refereegranskat)abstract
- On-line liquid chromatography-immunochemical detection (LC-ICD) provides the possibility to individually monitor cross-reactive compounds overcoming the need of tedious fraction collection. ICD is performed as a post-column reaction detection system and is based on a two-step immunoreaction. In the first step unlabelled antibodies are added to the LC effluent and allowed to react with antigens (analytes) eluting from the LC column. The amount of analytes bound to the antibodies is measured by adding, in a second step, labelled antigen to the reaction mixture. For quantitation, free and bound label need to be separated prior to detection. The present paper describes a hollow fibre module (HFM), which can be used for this purpose. Separation of free and bound label occurs on discrimination by size. Using biotin as a model compound, a detection limit of 30 nmol/l can be reached employing anti-biotin antibodies and a low-molecular-mass fluorescence label in the LC-ICD system. Additional to low-molecular-mass labels, the HFM allows the use of small enzyme labels. In this context, horseradish peroxidase-labelled biotin was used as a label in combination with antibodies in the immunochemical detection of biotin. This allows future implementation of commercially available enzyme immunoassay kits in continuous-flow immunochemical detection.
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| 10. |
- Lutz, Mareike, 1967-, et al.
(författare)
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Biochemical detection for direct bead surface analysis
- 1997
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Ingår i: Analytical Chemistry. - Washington : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 69:23, s. 4878-4884
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Tidskriftsartikel (refereegranskat)abstract
- A continuous-now biochemical detection system is presented which recognizes biologically active compounds immobilized to solid phases. This approach can be used to screen, for example, solid-phase combinatorial libraries for lead compounds. Biochemical detection is performed by mixing a plug of a solid-phase suspension with labeled affinity protein, During a short reaction time, the labeled affinity protein will only bind to ligands, i.e., compounds with biological activity. Hereafter, the free and bound labels are separated by means of a hollow fiber module, Quantitation of the free label is performed with a conventional now-through fluorescence detector, Total assay time amounts to less than 3 min. Biochemical detection for direct bead surface analysis was developed for two model systems. The first model system used fluorescence-labeled avidin as affinity protein and its ligands biotin and iminobiotin immobilized to agarose as analytes. The second model system used fluorescence-labeled antisheep (Fab)(2) fragments as affinity protein and different IgGs immobilized to agarose as analytes. The feasibility of this approach for recognition of solid-phase immobilized ligands was documented by screening 50 samples with a 100% hit rate.
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