| 1. |
- Brechmann, Nils Arnold, et al.
(författare)
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Pilot-scale process for magnetic bead purification of antibodies directly from non-clarified CHO cell culture
- 2019
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Ingår i: Biotechnology progress (Print). - : AIChE. - 8756-7938 .- 1520-6033.
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Tidskriftsartikel (refereegranskat)abstract
- High capacity magnetic protein A agarose beads, LOABeads PrtA, were used in the developmentof a new process for affinity purification of monoclonal antibodies (mAbs) from non-clarifiedCHO cell broth using a pilot-scale magnetic separator. The LOABeads had a maximum bindingcapacity of 65 mg/mL and an adsorption capacity of 25–42 mg IgG/mL bead in suspension for anIgG concentration of 1 to 8 g/L. Pilot-scale separation was initially tested in a mAb capture stepfrom 26 L clarified harvest. Small-scale experiments showed that similar mAb adsorptions wereobtained in cell broth containing 40 Å~ 106 cells/mL as in clarified supernatant. Two pilot-scalepurification runs were then performed on non-clarified cell broth from fed-batch runs of 16 L,where a rapid mAb adsorption ≥96.6% was observed after 1 h. This process using 1 L of magnetic beads had an overall mAb yield of 86% and 16 times concentration factor. After this single proteinA capture step, the mAb purity was similar to the one obtained by column chromatography, whilethe host cell protein content was very low, <10 ppm. Our results showed that this magnetic beadmAb purification process, using a dedicated pilot-scale separation device, was a highly efficientsingle step, which directly connected the culture to the downstream process without cell clarification.Purification of mAb directly from non-clarified cell broth without cell separation can providesignificant savings in terms of resources, operation time, and equipment, compared to legacy procedure of cell separation followed by column chromatography step.
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| 2. |
- Andraos, Rama, et al.
(författare)
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Autoantibodies associated with systemic sclerosis in three autoimmune diseases imprinted by type I interferon gene dysregulation: a comparison across SLE, primary Sjogrens syndrome and systemic sclerosis
- 2022
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Ingår i: Lupus Science and Medicine. - : BMJ PUBLISHING GROUP. - 2053-8790. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveSLE, primary Sjogrens syndrome (pSS) and systemic sclerosis (SSc) are heterogeneous autoimmune diseases with a dysregulated type I interferon (IFN) system. The diseases often show overlapping clinical manifestations, which may result in diagnostic challenges. We asked to which extent SSc-associated autoantibodies are present in SLE and pSS, and whether these link to serum IFN-alpha, clinical phenotypes and sex. Samples with clinical data from patients with SSc and healthy blood donors (HBDs) served as controls. Finally, the diagnostic performance of SSc-associated autoantibodies was evaluated.MethodsSamples from well-characterised subjects with SLE (n=510), pSS (n=116), SSc (n=57) and HBDs (n=236) were analysed using a commercially available immunoassay (EuroLine Systemic Sclerosis Profile (IgG)). IFN-alpha was quantified by ELISA. Self-reported data on Raynauds phenomenon (RP) were available.ResultsWith exceptions for anti-Ro52/SSA and anti-Th/To, SSc-associated autoantibodies were more frequent in SSc than in SLE, pSS and HBDs regardless of sex. IFN-alpha levels correlated with the number of positive SSc-associated autoantibodies (r=0.29, p<0.0001) and associated with Ro52/SSA positivity (p<0.0001). By using data from SLE, SSc and HBDs, RP was significantly associated with topoisomerase I, centromere protein (CENP)-B, RNA polymerase III 11 kDa, RNA polymerase III 155 kDa and PM-Scl100 whereas Ro52/SSA associated inversely with RP. In SLE, CENP-A was associated with immunological disorder, CENP-B with serositis and Ku with lupus nephritis. By combining analysis of ANA (immunofluorescence) with SSc-associated autoantibodies, the diagnostic sensitivity reached 98% and the specificity 33%.ConclusionsThe 13 specificities included in the EuroLine immunoassay are commonly detected in SSc, but they are also frequent among individuals with other diseases imprinted by type I IFNs. These findings are valuable when interpreting serological data on patients with suspected SSc, especially as patients may present with disease manifestations overlapping different rheumatological diseases. In SLE, we observed associations between manifestations and SSc-associated autoantibodies which have not previously been reported.
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| 3. |
- Bejhed Stjernberg, Rebecca, et al.
(författare)
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Magnetophoretic Transport Line System for Rapid On-Chip Attomole Protein Detection
- 2015
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 31:37, s. 10296-10302
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Tidskriftsartikel (refereegranskat)abstract
- A lab-on-a-chip traveling wave magnetophoresis approach for sensitive and rapid protein detection is reported. In this method, a chip-based magnetic microarray comprising lines of micrometer-sized thin film magnetic elements was used to control the movement of magnetic beads (MBs). The MBs and the chip were functionalized, forming a sandwich-type assay. The MBs were transported across a detection area, and the presence of target molecules resulted in the immobilization of MBs within this area. Target quantification was accomplished by MB counting in the detection area using an optical microscope. In order to demonstrate the versatility of the microarray, biotinylated antiavidin was selected as the target protein. In this case, avidin-functionalized MBs and an avidin-functionalized detection area were used. With a total assay time of 1 to 1.5 h (depending on the labeling approach used), a limit of detection in the attomole range was achieved. Compared to on-chip surface plasmon resonance biodetection systems, our method has a larger dynamic range and is about a factor of 500 times more sensitive. Furthermore, our MB transportation system can operate in any chip-based biosensor platform, thereby significantly improving traditional biosensors.
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| 4. |
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| 5. |
- Björnson, Kristofer, et al.
(författare)
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In Situ Pseudopotentials for Electronic Structure Theory
- 2021
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 125:27, s. 15103-15111
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Tidskriftsartikel (refereegranskat)abstract
- We present a general method of constructing in situ pseodopotentials from first-principles, all-electron, and full-potential electronic structure calculations of a solid. The method is applied to bcc Na, at low-temperature equilibrium volume. The essential steps of the method involve (i) calculating an all-electron Kohn-Sham eigenstate, (ii) replacing the oscillating part of the wave function (inside the muffin-tin spheres) of this state, with a smooth function, (iii) representing the smooth wave function in a Fourier series, and (iv) inverting the Kohn-Sham equation, to extract the pseudopotential that produces the state generated in steps i-iii. It is shown that an in situ pseudopotential can reproduce an all-electron full-potential eigenvalue up to the sixth significant digit. A comparison of the all-electron theory, in situ pseudopotential theory, and the standard nonlocal pseudopotential theory demonstrates good agreement, e.g., in the energy dispersion of the 3s band state of bcc Na.
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| 6. |
- Björnson, Kristofer
(författare)
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Topological band theory and Majorana fermions : With focus on self-consistent lattice models
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the most central concepts in condensed matter physics is the electronic band structure. Although band theory was established more than 80 years ago, recent developments have led to new insights that are formulated in the framework of topological band theory. In this thesis a subset of topological band theory is presented, with particular focus on topological supercon- ductors and accompanying Majorana fermions. While simple models are used to introduce basic concepts, a physically more realistic model is also studied intensely in the papers. Through self- consistent tight-binding calculations it is confirmed that Majorana fermions appear in vortex cores and at wire end points when the superconductor is in the topologically non-trivial phase. Many other properties such as the topological invariant, experimental signatures in the local density of states and spectral function, unconventional and odd-frequency pairing, the precense of spin-polarized currents and spin-polarization of the Majorana fermions, and a local π-phase shift in the order parameter at magnetic impurities are also investigated.
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| 7. |
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| 8. |
- Brechmann, Nils A., et al.
(författare)
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Proof-of-Concept of a Novel Cell Separation Technology Using Magnetic Agarose-Based Beads
- 2022
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Ingår i: MAGNETOCHEMISTRY. - : MDPI AG. - 2312-7481. ; 8:3, s. 34-
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Tidskriftsartikel (refereegranskat)abstract
- The safety of the cells used for Advanced Therapy Medicinal Products is crucial for patients. Reliable methods for the cell purification are very important for the commercialization of those new therapies. With the large production scale envisioned for commercialization, the cell isolation methods need to be efficient, robust, operationally simple and generic while ensuring cell biological functionality and safety. In this study, we used high magnetized magnetic agarose-based beads conjugated with protein A to develop a new method for cell separation. A high separation efficiency of 91% yield and consistent isolation performances were demonstrated using population mixtures of human mesenchymal stem cells and HER2(+) SKBR3 cells (80:20, 70:30 and 30:70). Additionally, high robustness against mechanical stress and minimal unspecific binding obtained with the protein A base conjugated magnetic beads were significant advantages in comparison with the same magnetic microparticles where the antibodies were covalently conjugated. This study provided insights on features of large high magnetized microparticles, which is promising for the large-scale application of cell purification.
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| 9. |
- Eriksson, Gunnar, et al.
(författare)
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Exploiting Syntax when Detecting Protein Names in Text
- 2002. - 1
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Ingår i: Proceedings of FMI Workshop on Natural Language Processing in Biomedical Applications.
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Konferensbidrag (refereegranskat)abstract
- This paper presents work on a method to detect names of proteins in running text. Our system - Yapex - uses a combination of lexical and syntactic knowledge, heuristic filters and a local dynamic dictionary. The syntactic information given by a general-purpose off-the-shelf parser supports the correct identification of the boundaries of protein names, and the local dynamic dictionary finds protein names in positions incompletely analysed by the parser. We present the different steps involved in our approach to protein tagging, and show how combinations of them influence recall and precision. We evaluate the system on a corpus of MEDLINE abstracts and compare it with the KeX system (Fukuda et al., 1998) along four different notions of correctness.
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| 10. |
- Eriksson, Gunnar, et al.
(författare)
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Using heuristics, syntax and a local dynamic dictionary for protein name tagging
- 2002. - 5
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Konferensbidrag (refereegranskat)abstract
- This paper presents work on a method to detect names of proteins in running text. The detection and categorisation of named entities, such as names of people, organisations and places, in classical MUC-style information extraction tasks (Borthwick 1998) might be regarded a solved problem. But names of proteins present a slightly different challenge because of their variant structural characteristics and the specifics of the text domains in which they appear. This certainly holds true for other biological substances, and probably for many other kinds of terminology as well. We will present the different steps involved in our approach to this problem, and show how combinations of them influence recall and precision.
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