| 1. |
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| 2. |
- Ahrentorp, Fredrik, et al.
(författare)
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Sensitive magnetic biodetection using magnetic multi-core nanoparticles and RCA coils
- 2017
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 427, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- We use functionalized iron oxide magnetic multi-core particles of 100 nm in size (hydrodynamic particle diameter) and AC susceptometry (ACS) methods to measure the binding reactions between the magnetic nanoparticles (MNPs) and bio-analyte products produced from DNA segments using the rolling circle amplification (RCA) method. We use sensitive induction detection techniques in order to measure the ACS response. The DNA is amplified via RCA to generate RCA coils with a specific size that is dependent on the amplification time. After about 75 min of amplification we obtain an average RCA coil diameter of about 1 mu m. We determine a theoretical limit of detection (LOD) in the range of 11 attomole (corresponding to an analyte concentration of 55 fM for a sample volume of 200 mu L) from the ACS dynamic response after the MNPs have bound to the RCA coils and the measured ACS readout noise. We also discuss further possible improvements of the LOD.
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| 3. |
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| 4. |
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| 5. |
- Bergman, Sara, et al.
(författare)
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Synthesis and Labelling of a Piperazine-Based Library of 11C-Labeled Ligands for Imaging of the Vesicular Acetylcholine Transporter
- 2014
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Ingår i: Journal of labelled compounds & radiopharmaceuticals. - : Wiley. - 0362-4803 .- 1099-1344. ; 57:8, s. 525-532
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Tidskriftsartikel (refereegranskat)abstract
- The cholinergic system is involved in neurodegenerative diseases, and visualization of cholinergic innervations with positron emission tomography (PET) would be a useful tool in understanding these diseases. A ligand for the vesicular acetylcholine transporter (VAChT), acknowledged as a marker for cholinergic neurons, could serve as such a PET tracer. The aim was to find a VAChT PET tracer using a library concept to create a small but diverse library of labeled compounds. From the same precursor and commercially available aryl iodides 6a-f, six potential VAChT PET tracers, [C-11]-(+/-)5a-f, were C-11-labeled by a palladium (0)-mediated aminocarbonylation, utilizing a standard protocol. The labeled compounds [C-11]-(+/-)5a-f were obtained in radiochemical purities >95% with decay-corrected radiochemical yields and specific radioactivities between 4-25% and 124-597 GBq/mu mol, respectively. Autoradiography studies were then conducted to assess the compounds binding selectivity for VAChT. Labeled compounds [C-11]-(+/-)5d and [C-11]-(+/-)5e showed specific binding but not enough to permit further preclinical studies. To conclude, a general method for a facile synthesis and labeling of a small piperazine-based library of potential PET tracers for imaging of VAChT was shown, and in upcoming work, another scaffold will be explored using this approach.
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| 6. |
- Blomgren, Mats, et al.
(författare)
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Decentralized market-based radio resource management in multi-network environments
- 2007
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Ingår i: IEEE VTS VEH TECHNOL CONF. - 9781424402656 ; , s. 2884-2889
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Konferensbidrag (refereegranskat)abstract
- For voice, an efficient radio resource management (RRM) essentially boils down to providing a predefined signal to interference ratio (SIR) at lowest cost possible and centralized schemes has, evidently, been an effective approach to address these problems. Delay-elastic data services, however, introduce both heterogeneous user requirements and possibilities for opportunistic RRM. One way, among others,to handle this would be to let autonomous trade-agents, acting on behalf of users, manage the radio resources, and this is our point of departure. We propose a market-based framework for decentralized RRM in environments populated by multiple, possibly heterogeneous, "access points" (APs), and the provided service for the users consists of file transfers. Resources (transmission time) are partitioned between users through a proportionally fair divisible auction. The problem at hand for the user (trade-agent), is then to determine how much resources it should purchase from the different APs in order to maximize its utility ("value for money"). Our results indicate that decentralized selfish bidding strategies are able to capitalize on temporary beneficial conditions and offer comparable performance with a centralized scheme (based on the 'mu C-rule') that requires knowledge about peak data-rates, queue lengths, and preferences for all users in the system.
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| 7. |
- Blomgren, Mats, et al.
(författare)
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Demand-responsive pricing in open wireless access markets
- 2007
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Ingår i: IEEE VTS VEH TECHNOL CONF. - 9781424402656 ; , s. 2990-2995
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Konferensbidrag (refereegranskat)abstract
- Radio resource management (RRM) across operator boundaries is emerging as a salient feature for wireless systems beyond 3G. Until recently, research has been confined to solutions where cooperating networks enter explicit sharing agreements that define how responsibilities and revenues should be divided. An alternative would be to share the infrastructure implicitly by establishing an open wireless access market wherein networks not only compete for users on a long-term time-scale, but also on a much shorter time-base. This could be realized with an architecture where autonomous trade-agents, that reside in terminals and access points (APs), manage the resources through negotiations. In this paper we develop a framework for studying demand-responsive pricing in contexts where APs with overlapping coverage compete for users. Resources are partitioned through a proportional fair divisible auction and our aim is to establish if, and when, an open market for wireless access can be se sustained. Compared to a scenario where APs cooperate, our results show that, an open access market results in better services at lower price which in the prolonging also yields more satisfied customers. As an effect demand will increase and, from the perspective of the APs, act as a counterbalance to the reduced prices. Thus, the revenue earned by the AN will be comparable to the one in which obtained through AP cooperation and monopoly (cartel) pricing. Generally speaking, the difference between the cooperative and noncooperative RRM is small when the demand is concave and increases with the convexity of demand.
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| 8. |
- Blomgren, Mats, et al.
(författare)
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Distributed demand-aware access selection in wireless multi-cell data networks
- 2007
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Ingår i: 2007 IEEE 18th International Symposium On Personal, Indoor And Mobile Radio Communications. - 9781424411436 ; , s. 2888-2892
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Konferensbidrag (refereegranskat)abstract
- Regardless of advances in transmission technology, wireless broadband access will result in that fewer active users can be supported in a given cell. This may, due to lower levels of statistical multiplexing, yield in an unbalanced network. For such contexts load aware access point (AP) selection (load balancing) has been proposed as a means to increase network performance. This paper evaluates the downlink capacity (maximum number of users that can be admitted given a throughput requirement) of distributed load aware AP selection criteria for a well planned network, where the expected number of users per cell coincide. We propose a market based algorithm in which AP selection is aided by market mechanisms. In contrast to most of the existing research, we account for that interference levels generated in different cells depend on user assignment, and therefore varies as terminals perform handoff. Compared to single-frequency systems where users base their selection on the received signal strength our results show that the downlink capacity can be increased with around 25 percent by introducing a channel plan in combination with demand, or load, aware AP selection criteria. This gain is fairly insensitive to the throughput requirement and does not come at the expense of uplink performance. To benefit from demand metrics it is, however, of paramount importance that the entire system bandwidth is not reused in all cells.
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| 9. |
- Blomgren, Mats, et al.
(författare)
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Idempotent transformations of finite groups
- 2013
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Ingår i: Advances in Mathematics. - : Elsevier BV. - 0001-8708 .- 1090-2082. ; 233:1, s. 56-86
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Tidskriftsartikel (refereegranskat)abstract
- We describe the action of idempotent transformations on finite groups. We show that finiteness is preserved by such transformations and enumerate all possible values such transformations can assign to a fixed finite simple group. This is done in terms of the first two homology groups. We prove for example that except special linear groups, such an orbit can have at most 7 elements. We also study the action of monomials of idempotent transformations on finite groups and show for example that orbits of this action are always finite.
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| 10. |
- Brinson, Robert G., et al.
(författare)
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Enabling adoption of 2D-NMR for the higher order structure assessment of monoclonal antibody therapeutics
- 2019
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Ingår i: mAbs. - : Informa UK Limited. - 1942-0862 .- 1942-0870. ; 11:1, s. 94-105
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Tidskriftsartikel (refereegranskat)abstract
- The increased interest in using monoclonal antibodies (mAbs) as a platform for biopharmaceuticals has led to the need for new analytical techniques that can precisely assess physicochemical properties of these large and very complex drugs for the purpose of correctly identifying quality attributes (QA). One QA, higher order structure (HOS), is unique to biopharmaceuticals and essential for establishing consistency in biopharmaceutical manufacturing, detecting process-related variations from manufacturing changes and establishing comparability between biologic products. To address this measurement challenge, two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) methods were introduced that allow for the precise atomic-level comparison of the HOS between two proteins, including mAbs. Here, an inter-laboratory comparison involving 26 industrial, government and academic laboratories worldwide was performed as a benchmark using the NISTmAb, from the National Institute of Standards and Technology (NIST), to facilitate the translation of the 2D-NMR method into routine use for biopharmaceutical product development. Two-dimensional H-1,N-15 and H-1,C-13 NMR spectra were acquired with harmonized experimental protocols on the unlabeled Fab domain and a uniformly enriched-N-15, 20%-C-13-enriched system suitability sample derived from the NISTmAb. Chemometric analyses from over 400 spectral maps acquired on 39 different NMR spectrometers ranging from 500 MHz to 900 MHz demonstrate spectral fingerprints that are fit-for-purpose for the assessment of HOS. The 2D-NMR method is shown to provide the measurement reliability needed to move the technique from an emerging technology to a harmonized, routine measurement that can be generally applied with great confidence to high precision assessments of the HOS of mAb-based biotherapeutics.
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| 11. |
- Gokturk, Camilla, et al.
(författare)
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Macrovascular changes in mice overexpressing human semicarbazide-sensitive amine oxidase in smooth muscle cells
- 2007
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Ingår i: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 20:7, s. 743-750
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Tidskriftsartikel (refereegranskat)abstract
- Background: The catalytic activity of semicarbazide-sensitive amine oxidase (SSAO) is increased in diabetes, as well as in other disorders of cardiovascular origin. Our hypothesis is that SSAO is involved in the synthesis or maturation of elastin in vascular tissue. An increased SSAO activity can thereby be involved in the development of vascular damage. Methods: Elastin quantification was performed in aorta of transgenic mice overexpressing the human form of SSAO, using electron microscopy. Furthermore, lung capacity was measured using a spirometry-mimicking method, developed for mice. The effect of vasoactive substances was estimated by measuring mean arterial pressure and pulse pressure under anesthesia. Results: No differences in elastin quantity or lung capacity could be observed between transgenic or nontransgenic littermates. Pulse pressure was higher in transgenic mice, and electron microscopy of aorta showed elastin fibers parallel with the aorta wall (ie, straight fibers instead of folded compared with control mice). No difference in the response to adrenaline or sodium chloride was observed between the transgenic and control mice. The control mice had a clear decrease in blood pressure (BP) with a longer duration as a response to injection of a nitric oxide (NO) donor, sodium nitroprusside, compared with transgenic mice where only a minor response was observed. The SSAO activity in serum of control mice was elevated in response to injection of the NO donor, but not in response to a ganglion blocker. Conclusions: An elevated pulse pressure, together with an abnormal elastin structure in the aorta, suggests a rigidity of large arteries as a result of an elevated SSAO activity as well as a physiologic role for SSAO in elastin maturation.
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| 12. |
- Gramenius, Jakob, et al.
(författare)
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Praktikfallet Rydab
- 1999
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Bok (övrigt vetenskapligt/konstnärligt)
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| 13. |
- Gunnarsson, Fredrik, et al.
(författare)
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Downtilted Base Station Antennas - A Simulation Model Proposal and Impact on HSPA and LTE Performance
- 2008
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Ingår i: Proceedings of the 68th IEEE Vehicular Technology Conference. - 9781424417223 - 9781424417216 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a low-complexity model for vertical antenna radiation patterns, e.g. for inclusion in system- level simulations. They can be seen as extensions to the horizontal radiation pattern model used in 3GPP simulation scenarios. The model is verified against and compared to predicted and measured data from real networks. The impact on system-level performance is also investigated. It is seen that using the proposed model, simulated geometry distributions and soft handover statistics closely matching those of real networks may be achieved. The analysis also concludes that many real networks have better cell isolation than what is modeled by the 3GPP antenna model. As a consequence, the horizontal radiation pattern model significantly under-estimates the system level performance in such networks. Furthermore, the proposed model is used to assess the LTE and HSPA system-level performance for realistic scenarios.
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| 14. |
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| 15. |
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| 16. |
- Karlsson, Lars O, 1975, et al.
(författare)
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Constitutive PGC-1 alpha Overexpression in Skeletal Muscle Does Not Improve Morphological Outcome in Mouse Models of Brain Irradiation or Cortical Stroke
- 2018
-
Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522 .- 1873-7544. ; 384, s. 314-328
-
Tidskriftsartikel (refereegranskat)abstract
- Physical exercise can improve morphological outcomes after ischemic stroke and ameliorate irradiation-induced reduction of hippocampal neurogenesis in rodents, but the mechanisms underlying these effects remain largely unknown. The transcription factor peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha) is considered to be one of the central factors responsible for exercise-induced benefits in skeletal muscle, including the release of neurotrophic factors into the circulation. In order to test if PGC-1 alpha overexpression in skeletal muscle could simulate the exercise-induced effects on recovery after cranial irradiation and stroke, we used male adult transgenic mice overexpressing murine PGC-1 alpha under the control of muscle creatinine kinase promoter and subjected them to either whole brain irradiation at a dose of 4 Gy or photothrombotic stroke to the sensory motor cortex. Muscular PGC-1 alpha overexpression did not ameliorate irradiation-induced reduction of newborn BrdU-labeled cells in the dentate gyrus, immature neurons, or newborn mature neurons. In the stroke model, muscular overexpression of PGC-1 alpha resulted in an increased infarct size without any changes in microglia activation or reactive astrocytosis. No difference could be detected in the number of migrating neural progenitor cells from the subventricular zone to the lesioned neocortex or in vascular density of the contralateral neocortex in comparison to wildtype animals. We conclude that forced muscular overexpression of PGC-1 alpha does not have a beneficial effect on hippocampal neurogenesis after irradiation, but rather a detrimental effect on the infarct volume after stroke in mice. This suggests that artificial muscle activation through the PGC-1 alpha pathway is not sufficient to mimic exercise-induced recovery after cranial irradiation and stroke. (C) 2018 IBRO. Published by Elsevier Ltd. All rights reserved.
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| 17. |
- Karlsson, Lars O, 1975, et al.
(författare)
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Constitutive PGC-1 alpha overexpression in skeletal muscle does not protect from age-dependent decline in neurogenesis
- 2019
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Aerobic exercise prevents age-dependent decline in cognition and hippocampal neurogenesis. The transcription factor peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC-1 alpha) mediates many of the exercise-induced benefits in skeletal muscle, including the release of factors into the circulation with neurotrophic effects. We use a transgenic mouse model with muscle-specific overexpression of PGC-1 alpha to study the contribution of chronic muscle activation on exercise-induced effects on hippocampal neurogenesis in aging. Young and old transgenic and wild type animals of both sexes displayed a robust age-related reduction in newborn BrdU+-cells, immature neurons (DCX+-cells) and new mature BrdU(+)/NeuN(+)-neurons in the dentate gyrus. No differences were detected between genotypes or sexes. Analysis of serum proteins showed a tendency towards increased levels of myokines and reduced levels of pro-inflammatory cytokines for transgenic animals, but only musclin was found to be significantly up-regulated in transgenic animals. We conclude that constitutive muscular overexpression of PGC-1 alpha, despite potent systemic changes, is insufficient for mimicking exercise-induced effects on hippocampal neurogenesis in aging. Continued studies are required to investigate the complex molecular mechanisms by which circulating signals could mediate exercise-induced effects on the central nervous system in disease and aging, with the aim of discovering new therapeutic possibilities for patients.
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| 18. |
- Lekander, M, et al.
(författare)
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Anticipatory immune changes in women treated with chemotherapy for ovarian-cancer
- 1995
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Ingår i: INTERNATIONAL JOURNAL OF BEHAVIORAL MEDICINE. - : LAWRENCE ERLBAUM ASSOC INC. - 1070-5503. ; 2:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Immune parameters were assessed in 22 women before chemotherapy for ovarian cancer and compared with assessment made at home 2 days earlier. In the hospital, as compared to home measures, patients had a lower percentage of lymphocytes and monocytes and a
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| 19. |
- Lekander, M, et al.
(författare)
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Social support and immune status during and after chemotherapy for breast cancer
- 1996
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Ingår i: ACTA ONCOLOGICA. - : SCANDINAVIAN UNIVERSITY PRESS. - 0284-186X. ; 35:1, s. 31-37
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Tidskriftsartikel (refereegranskat)abstract
- Social support and immune status were assessed in women treated with adjuvant chemotherapy for breast cancer. Perception of enhanced attachment was associated with an increased number of white blood cell levels three months after, but not during, chemoth
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| 20. |
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| 21. |
- Lundström, Jan O, et al.
(författare)
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The geographic distribution of mosquito species in Sweden
- 2013
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Ingår i: Journal of the European Mosquito Control Association. - 2054-930X .- 1460-6127. ; 31, s. 21-35
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Tidskriftsartikel (refereegranskat)abstract
- Surveillance of the actual distribution of mosquito species in Northern Europe is fundamental for evaluating risk for emerging pathogens, and for research on potential vectors. The Swedish mosquito fauna composition and geographic distribution, originally described by Professor Christine Dahl in the 1970´s, included 43 species. We have compiled the information published from 1978 to 2012, and our own surveillance data from 2001 to 2013, and compared this with the species list and geographic distribution provided in "Taxonomy and geographic distribution of Swedish Culicidae" by Dahl (1977). New species detected during these 36 years were Culiseta (Culicella) ochroptera (Peus, 1935) published 1984, Aedes (Aedes) rossicus Dolbeskin, Goritzkaja & Mitrofanova, 1930 published 1986, Anopheles (Anopheles) beklemishevi published 1986, Aedes (Ochlerotatus) euedes (Howard, Dyar & Knab, 1912) published 2001, Aedes (Ochlerotatus) nigrinus (Eckstein, 1918) first recorded in 2012, and Anopheles (Anopheles) algeriensis Theobald, 1903, first recorded in 2013. We provide maps with the distribution by province for each species, including historic information up until 1977, and new records from 1978 to 2013, showing the similarities and differences between the old and the new records. Important findings in recent years include the wide distribution of the Sindbis virus enzootic vector Culex (Culex) torrentium Martinii, 1925, and the more limited distribution of the potential West Nile virus vector Culex (Culex) pipiens Linnaeus, 1758. The updated list of mosquito species in Sweden now includes 49 species.
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| 22. |
- Möller, Anders, et al.
(författare)
-
A Stability of High Order Distributed Power Control Algorithms in Cellular Networks
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In radio resource management for cellular networks a trade-off has to be made between the congestion level, related to the cell coverage and the intercell interference, and the Quality of Service (QoS), or data rates of the users. This is implemented by using a fast inner power control algorithm and an outer rate control algorithm, working on a slower time scale. Due to the distributed nature of the network, both the information and the control are distributed. Measurements of the congestion and the QoS are used in the control algorithms and this introduces a nonlinear feedback. Another complicating factor is that filtering, computations and information exchange in the network introduce time delays. In this paper we propose a general high order model as a cascade system with an outer and inner control loop. The control algorithms use distributed information available in the network. The full system model includes the nonlinear feedback from congestion and QoS measurements, time delays and time-scale modeling. We provide sufficient conditions for stability and convergence of the system. Our primary analysis tool is input output theory.
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| 23. |
- Möller, Anders, et al.
(författare)
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Congestion-based Rate and Power Control in Wireless Cellular Networks
- 2011
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Ingår i: 2011 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE (GLOBECOM 2011). - New York : IEEE. - 9781424492688 ; , s. 6133508-
-
Konferensbidrag (refereegranskat)abstract
- In a cellular network it is necessary to make a trade-off between congestion and Quality of Service (QoS) of the users. To ensure good system performance in uplink of a WCDMA network, control loops are used to adapt to changing radio and interference conditions. A fast inner power control loop updates the transmission powers of the mobiles based on measurements related to QoS, which are compared to a reference value. The reference value is set dynamically by a slower outer rate control loop that uses measurements of congestion. There is a time-scale difference between the loops, but joint dynamics cannot be neglected. In this paper we derive a high order system model with distributed feedback control based on locally measurable information. We model the time-scale difference between the loops and include this in the model. We give sufficient conditions for stability using control theoretic methods and validate the model and results by simulations.
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| 24. |
- Möller, Anders, et al.
(författare)
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Stability of Rate and Power Control Algorithms in Wireless Cellular Networks
- 2011
-
Ingår i: 2011 50th IEEE Conference On Decision And Control And European Control Conference (CDC-ECC). - : IEEE. - 9781612848006 ; , s. 4535-4541
-
Konferensbidrag (refereegranskat)abstract
- In radio resource management for cellular networks a trade-off has to be made between the congestion level, related to cell coverage and intercell interference, and the Quality of Service (QoS) or data rates of the users. This is implemented by using a fast inner power control loop and an outer rate control algorithm, working on a slower time scale. Due to the distributed nature of the network, both information and control is distributed. Measurements of congestion and QoS are used in the control loops and this introduces a nonlinear feedback. Another complicating factor is that filtering, computations and information exchange in the network introduce time delays. In this paper we propose a general high order model as a cascade system with an outer and inner control loop. The control algorithms use distributed information available in the network. The full system model includes the nonlinear feedback from congestion and QoS measurements, time delays and time scale modelling. We provide sufficient conditions for stability and convergence of the system. Our primary analysis tool is input output theory.
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| 25. |
- Nilsson, Mats F., et al.
(författare)
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Improved methodology for identifying the teratogenic potential in early drug development of hERG channel blocking drugs
- 2010
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Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 29:2, s. 156-163
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Tidskriftsartikel (refereegranskat)abstract
- Drugs blocking the potassium current IKr of the heart (via hERG channel-inhibition) have the potential to cause hypoxia-related teratogenic effects. However, this activity may be missed in conventional teratology studies because repeat dosing may cause resorptions. The aim of the present study was to investigate an alternative protocol to reveal the teratogenic potential of IKr-blocking drugs. The IKr blocker astemizole, given as a single dose (80mg/kg) on gestation day (GD) 13 to pregnant rats caused digital defects. In whole rat embryo culture (2h) on GD 13, astemizole caused a decrease in embryonic heart rate at 20nM, and arrhythmias at 200-400nM. Cetirizine, without IKr-blocking properties, did not affect the rat embryonic heart in vitro. The present study shows that single dose testing on sensitive days of development, together with whole embryo culture, can be a useful methodology to better characterize the teratogenic potential of IKr-blocking drugs.
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| 26. |
- Sepehri, Sobhan, 1986, et al.
(författare)
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Characterization of Binding of Magnetic Nanoparticles to Rolling Circle Amplification Products by Turn-On Magnetic Assay
- 2019
-
Ingår i: Biosensors-Basel. - : MDPI AG. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- The specific binding of oligonucleotide-tagged 100 nm magnetic nanoparticles (MNPs) to rolling circle products (RCPs) is investigated using our newly developed differential homogenous magnetic assay (DHMA). The DHMA measures ac magnetic susceptibility from a test and a control samples simultaneously and eliminates magnetic background signal. Therefore, the DHMA can reveal details of binding kinetics of magnetic nanoparticles at very low concentrations of RCPs. From the analysis of the imaginary part of the DHMA signal, we find that smaller MNPs in the particle ensemble bind first to the RCPs. When the RCP concentration increases, we observe the formation of agglomerates, which leads to lower number of MNPs per RCP at higher concentrations of RCPs. The results thus indicate that a full frequency range of ac susceptibility observation is necessary to detect low concentrations of target RCPs and a long amplification time is not required as it does not significantly increase the number of MNPs per RCP. The findings are critical for understanding the underlying microscopic binding process for improving the assay performance. They furthermore suggest DHMA is a powerful technique for dynamically characterizing the binding interactions between MNPs and biomolecules in fluid volumes.
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| 27. |
- Sepehri, Sobhan, 1986, et al.
(författare)
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Homogeneous Differential Magnetic Assay
- 2019
-
Ingår i: Acs Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 4:9, s. 2381-2388
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Tidskriftsartikel (refereegranskat)abstract
- Assays are widely used for detection of various targets, including pathogens, drugs, and toxins. Homogeneous assays are promising for the realization of point-of-care diagnostics as they do not require separation, immobilization, or washing steps. For low concentrations of target molecules, the speed and sensitivity of homogeneous assays have hitherto been limited by slow binding kinetics, time-consuming amplification steps, and the presence of a high background signal. Here, we present a homogeneous differential magnetic assay that utilizes a differential magnetic readout that eliminates previous limitations of homogeneous assays. The assay uses a gradiometer sensor configuration combined with precise microfluidic sample handling. This enables simultaneous differential measurement sample containing a synthesized Vibrio cholerae target and a negative control sample, which reduces the background signal and increases the readout speed. Very low concentrations of targets down to femtomolar levels are thus detectable without any additional amplification of the number of targets. Our homogeneous differential magnetic assay method opens new possibilities for rapid and highly sensitive diagnostics at the point of care.
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| 28. |
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| 29. |
- Sepehri, Sobhan, et al.
(författare)
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Study of magnetic beads-DNA coils binding kinetics using a differential homogeneous magnetic assay
- 2019
-
Ingår i: Joint European Magnetic Symposia (JEMS) 2019. - Uppsala.
-
Konferensbidrag (refereegranskat)abstract
- The binding kinetics of magnetic nanoparticles (MNPs) to rolling circle amplification products (RCPs) is investigated using a differential homogenous magnetic assay (DHMA)1. The DHMA utilizes a microfluidic device to measure the differential ac susceptibility signal between a reference and a test sample, taking advantage of the symmetry in a high-Tc SQUID gradiometer sensor2. The DHMA signal is related to the relative differences in the particle distribution of the two samples, and the background magnetic signal is thus eliminated. Therefore, minuscule changes in the nanoparticle’s concentration and size distribution of the test sample are directly detectable in the solution. This makes the DHMA a superior technique to characterize the binding interaction of the MNPs to biomolecules like RCPs specially at very low concentrations. The DHMA reveals that there is a competitive dynamic process between the MNP labelled RCPs and the unbound MNPs in the solution as a function of the RCP concentrations. The evidence of this dynamic in the signal fades as the MNP-RCP agglomerates are formed. The DHMA also shows that the smaller MNPs in the MNP size distribution take precedence over the larger MNP in immobilization on the RCPs. Comparing the DHMA responses with the turn-off detection method indicates that a full frequency range ac susceptibility observation is necessary when detecting low concentration of target RCPs. The findings are critical for understanding the underlying microscopic binding process and improving the assay performance. [1] Sepehri, S. et al, Differential homogeneous magnetic assay. Submitted. [2] Sepehri, S. et al. Volume-amplified magnetic bioassay integrated with microfluidic sample handling and high-Tc SQUID magnetic readout. APL Bioeng. 2, 016102 (2018).
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| 30. |
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| 31. |
- Sriviriyakul, Thana, et al.
(författare)
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Nanorheological studies of xanthan/water solutions using magnetic nanoparticles
- 2019
-
Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier B.V.. - 0304-8853 .- 1873-4766. ; 473, s. 268-271
-
Tidskriftsartikel (refereegranskat)abstract
- We show results of nanorheological studies of different concentrations of xanthan (non-Newtonian fluid) in water using magnetic nanoparticles (MNPs) together with the AC susceptibility (ACS) vs frequency method. For comparison we also show the ACS response for different concentrations of glycerol in water (Newtonian fluid). The ACS response is measured, and the data is modelled using dynamic magnetic models and different viscoelastic models. We study the ACS response (in-phase and out-of-phase ACS components) at different concentrations of xanthan in water (up to 1 wt% xanthan) and with a constant concentration of MNPs. We use MNP systems that show Brownian relaxation (sensitive to changes in the environmental properties around the MNPs). ACS measurements are performed using the DynoMag system. The Brownian relaxation of the MNP system peak is shifting down in frequency and the ACS response is broadening and decreases due to changes in the viscoelastic properties around the MNPs in the xanthan solution. The viscosity and the storage moduli are determined at each excitation frequency and compared with traditional macroscopic small amplitude oscillatory shear rheological measurements. The results from the traditional rheological and nanorheological measurements correlate well at higher xanthan concentration.
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| 32. |
- Sundberg, Jonas, et al.
(författare)
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Recurrence rates after surgical removal of oral leukoplakia-A prospective longitudinal multi-centre study.
- 2019
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 14:12
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Tidskriftsartikel (refereegranskat)abstract
- Oral leukoplakia (OL) is a potentially malignant oral disorder. The Gold Standard treatment is to remove surgically the OL. Despite optimal surgery, the recurrence rates are estimated to be 30%. The reason for this is unknown. The aim of this study was to investigate the clinical factors that correlate with recurrence after surgical removal of OL. In a prospective study data were collected from 226 patients with OL. Forty-six patients were excluded due to incomplete records or concomitant presence of other oral mucosal diseases. Overall, 180 patients proceeded to analysis (94 women and 86 men; mean age, 62 years; age range, 28-92 years). Clinical data, such as gender, diagnosis (homogeneous/non-homogeneous leukoplakia), location, size, tobacco and alcohol use, verified histopathological diagnosis, and clinical photograph, were obtained. In patients who were eligible for surgery, the OL was surgically removed with a margin. To establish recurrence, a healthy mucosa between the surgery and recurrence had to be confirmed in the records or clinical photographs. Statistical analysis was performed with the level of significance set at P<0.05. Of the 180 patients diagnosed with OL, 57% (N = 103) underwent surgical removal in toto. Recurrence was observed in 43 OL. The cumulative incidence of recurrence of OL was 45% after 4 years and 49% after 5 years. Fifty-six percent (N = 23) of the non-homogeneous type recurred. Among snuff-users 73% (N = 8) cases of OL recurred. A non-homogeneous type of OL and the use of snuff were significantly associated with recurrence after surgical excision (P = 0.021 and P = 0.003, respectively). Recurrence was also significantly associated with cancer transformation (P<0.001). No significant differences were found between recurrence and any of the following: dysplasia, site of lesion, size, multiple vs. solitary OL, gender, age, use of alcohol or smoking. In conclusion, clinical factors that predict recurrence of OL are non-homogeneous type and use of snuff.
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| 33. |
- Tongur, Stefan, 1986-
(författare)
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Preparing for takeoff : Analyzing the development of electric road systems from a business model perspective
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Electric road systems (ERS) are road transportation systems based on technologies that support electric power transfer from roads to vehicles in motion. Transition toward alternative technologies, such as ERS, is necessary in order to achieve the sustainability goals in road transportation. While several studies have emphasized that new business models are necessary in order to commercialize such technologies, they tend to neglect the fact thatmany of these technologies require socio-technical change, such as investments in alternative infrastructure.Hence, this thesis examines the relationship between business models and socio-technical change.The research was explorative and based on two case studies investigating the development of ERS: a longitudinal case study in Sweden and an in-depth case study in Los Angeles, USA. The findings suggest different roles that business models can have in different types of projects when preparing ERS for commercial takeoff: first, new business models were not part of the pilot projects which focused on radical innovation; second, business models were developed in demonstration projects with user interactions; and, third, business models were evaluated, and in this case rejected, in a deployment project aiming to transform the existing socio-technical system.Given these findings, this thesis argues that the business model concept could be used as a perspective from which to understand the evolutionary processes that take place during the early phases of transition, and that the challenges of commercializing and deploying systemic innovations, such as ERS, are more complex than often accounted for in the business model and sustainability transition literature.This thesis also discusses whether or not ERS is likely to take off. Thereby, this research nuances our view of predevelopment processes of a niche innovation before it has actually taken off and improves our understanding of what hinders and enables sustainable transitions.
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| 34. |
- Wang, Xiaoyang, 1965, et al.
(författare)
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The nonerythropoietic asialoerythropoietin protects against neonatal hypoxia-ischemia as potently as erythropoietin.
- 2004
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Ingår i: Journal of neurochemistry. - : Wiley. - 0022-3042 .- 1471-4159. ; 91:4, s. 900-10
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Tidskriftsartikel (refereegranskat)abstract
- Recently, erythropoietin (EPO) and the nonerythropoietic derivative asialoEPO have been linked to tissue protection in the nervous system. In this study, we tested their effects in a model of neonatal hypoxia-ischemia (HI) in 7-day-old rats (unilateral carotid ligation and exposure to 7.7% O(2) for 50 min). EPO (10 U/g body weight = 80 ng/g; n = 24), asialoEPO (80 ng/g; n = 23) or vehicle (phosphate-buffered saline with 0.1% human serum albumin; n = 24) was injected intraperitoneally 4 h before HI. Both drugs were protective, as judged by measuring the infarct volumes, neuropathological score and gross morphological score. The infarct volumes were significantly reduced by both EPO (52%) and asialoEPO (55%) treatment, even though the plasma levels of asialoEPO had dropped below the detection limit (1 pm) at the onset of HI, while those of EPO were in the nanomolar range. Thus, a brief trigger by asialoEPO before the insult appears to be sufficient for protection. Proteomics analysis after asialoEPO treatment alone (no HI) revealed at least one differentially up-regulated protein, synaptosome-associated protein of 25 kDa (SNAP-25). Activation (phosphorylation) of ERK was significantly reduced in asialoEPO-treated animals after HI. EPO and the nonerythropoietic asialoEPO both provided significant and equal neuroprotection when administered 4 h prior to HI in 7-day-old rats. The protection might be related to reduced ERK activation and up-regulation of SNAP-25.
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| 35. |
- Wang, Xiaoyang, 1965, et al.
(författare)
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X-linked inhibitor of apoptosis (XIAP) protein protects against caspase activation and tissue loss after neonatal hypoxia-ischemia
- 2004
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Ingår i: Neurobiol Dis. - Univ Gothenburg, Dept Physiol, Perinatal Ctr, SE-40530 Gothenburg, Sweden. Zhengzhou Univ, Affiliated Hosp 3, Dept Pediat, Zhengzhou 450052, Peoples R China. Univ Gothenburg, Sahlgrens Univ Hosp, Dept Obstet & Gynecol, SE-41685 Gothenburg, Sweden. Uppsala Univ, Dept Neurosci, SE-75123 Uppsala, Sweden. Univ Gothenburg, Dept Med Biophys, SE-40530 Gothenburg, Sweden. Univ Gothenburg, Queen Silvia Childrens Hosp, Dept Pediat, SE-41685 Gothenburg, Sweden. : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 0969-9961 .- 1095-953X. ; 16:1, s. 179-89
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Tidskriftsartikel (refereegranskat)abstract
- Nine-day-old transgenic XIAP overexpressing (TG-XIAP) and wild-type mice were subjected to left carotid artery ligation and 10% O(2) for 60 min, leading to widespread infarctions in the ipsilateral hemisphere during reperfusion. The activation of caspase-3 and -9 seen in wild-type animals was virtually abolished in TG-XIAP mice. Tissue loss was significantly reduced from 54.4 +/- 4.1 mm(3) (mean +/- SEM) in wild-type mice to 33.1 +/- 2.1 mm(3) in the TG-XIAP mice. Injured neurons displayed stronger XIAP staining during reperfusion, particularly in the nuclei. XIAP was colocalized with XAF-1, Smac, and HtrA2 in injured neurons after hypoxia-ischemia (HI). XIAP was cleaved after HI, and Smac immunoprecipitation co-precipitated a 25-kDa C-terminal fragment of XIAP, indicating that Smac preferentially bound to cleaved XIAP. These findings provide the first evidence that increased XIAP levels protect the neonatal brain against HI.
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