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| 2. |
- Dijulio, Douglas D., et al.
(författare)
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Characterization of the radiation background at the Spallation Neutron Source
- 2016
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Ingår i: VI European Conference On Neutron Scattering (ECNS2015). - : IOP Publishing. ; 746:1
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Konferensbidrag (refereegranskat)abstract
- We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis He-4 detector, and a standard Nal photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.
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| 3. |
- Kirstein, Oliver, et al.
(författare)
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Neutron position sensitive detectors for the ESS
- 2014
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Ingår i: Proceedings of Science. - : Proceedings of Science (PoS). ; Vertex2014, s. 029-029
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Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials. It will be a long pulse source, with an average beam power of 5 MW delivered to the target station. The ESS is in the construction phase, which started in 2013 with the completion of the Technical Design Report (TDR). The instruments are being selected from conceptual proposals submitted by groups from around Europe. These instruments present numerous challenges for detector technology in the absence of the availability of Helium-3, which is the default choice for detectors for instruments built until today and due to the extreme rates expected across the ESS instrument suite. Additionally a new generation of source requires a new generation of detector technologies to fully exploit the opportunities that this source provides. To meet this challenge at a green-field site, the detectors will be sourced from partners across Europe through numerous in-kind arrangements; a process that is somewhat novel for the neutron scattering community. This contribution presents briefly the current status of detectors for the ESS, and outlines the timeline to completion. For a conjectured instrument suite based upon instruments recommended for construction, a recently updated snapshot of the current expected detector requirements is presented. A strategy outline as to how these requirements might be tackled by novel detector developments is shown. In terms of future developments for the neutron community, synergies should be sought with other disciples, as recognized by various recent initiatives in Europe, in the context of the fundamentally multi-disciplinary nature of detectors. This strategy has at its basis the in-kind and collaborative partnerships necessary to be able to produce optimally performant detectors that allow the ESS instruments to be world-leading. This foresees and encourages a high level of collaboration and interdependence at its core, and rather than each group being all-rounders in every technology, the further development of centres of excellence across Europe for particular technologies and niches.
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| 4. |
- Nistor, Catalin, et al.
(författare)
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A glucose dehydrogenase biosensor as an additional signal amplification step in an enzyme-flow immunoassay.
- 2002
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Ingår i: Analyst. - : Royal Society of Chemistry (RSC). - 1364-5528. ; 127:8, s. 1076-1081
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Tidskriftsartikel (refereegranskat)abstract
- Both the antibody affinity and the detectability of the label are essential in deciding the final characteristics of a heterogeneous immunoassay. This paper describes an approach to obtain a supplementary enhancement of the signal generated by using an enzyme label, e.g., by including the product of the enzymatic reaction in an additional amplification cycle during the detection step performed with an amperometric biosensor based on glucose dehydrogenase (GDH). An immunoassay format with a labelled analyte derivative that competes with the analyte present in the sample for a limited amount of antibody binding sites was employed. The beta-galactosidase label hydrolyses the substrate aminophenyl-beta-galactopyranoside, and the generated aminophenol enters then into a bioelectrocatalytic amplification cycle at the GDH biosensor. The principle was applied for determination of 4-nitrophenol, with the best minimal concentration of 1.5 microM and a midpoint of the calibration of 24 microM. The potentials and limitations of such a system are discussed.
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| 5. |
- Pfeiffer, Dorothea, et al.
(författare)
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Genetic Imbalance Is Associated With Functional Outcome After Ischemic Stroke
- 2019
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Ingår i: Stroke. - 1524-4628. ; 50:2, s. 298-304
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose- We sought to explore the effect of genetic imbalance on functional outcome after ischemic stroke (IS). Methods- Copy number variation was identified in high-density single-nucleotide polymorphism microarray data of IS patients from the CADISP (Cervical Artery Dissection and Ischemic Stroke Patients) and SiGN (Stroke Genetics Network)/GISCOME (Genetics of Ischaemic Stroke Functional Outcome) networks. Genetic imbalance, defined as total number of protein-coding genes affected by copy number variations in an individual, was compared between patients with favorable (modified Rankin Scale score of 0-2) and unfavorable (modified Rankin Scale score of ≥3) outcome after 3 months. Subgroup analyses were confined to patients with imbalance affecting ohnologs-a class of dose-sensitive genes, or to those with imbalance not affecting ohnologs. The association of imbalance with outcome was analyzed by logistic regression analysis, adjusted for age, sex, stroke subtype, stroke severity, and ancestry. Results- The study sample comprised 816 CADISP patients (age 44.2±10.3 years) and 2498 SiGN/GISCOME patients (age 67.7±14.2 years). Outcome was unfavorable in 122 CADISP and 889 SiGN/GISCOME patients. Multivariate logistic regression analysis revealed that increased genetic imbalance was associated with less favorable outcome in both samples (CADISP: P=0.0007; odds ratio=0.89; 95% CI, 0.82-0.95 and SiGN/GISCOME: P=0.0036; odds ratio=0.94; 95% CI, 0.91-0.98). The association was independent of age, sex, stroke severity on admission, stroke subtype, and ancestry. On subgroup analysis, imbalance affecting ohnologs was associated with outcome (CADISP: odds ratio=0.88; 95% CI, 0.80-0.95 and SiGN/GISCOME: odds ratio=0.93; 95% CI, 0.89-0.98) whereas imbalance without ohnologs lacked such an association. Conclusions- Increased genetic imbalance was associated with poorer functional outcome after IS in both study populations. Subgroup analysis revealed that this association was driven by presence of ohnologs in the respective copy number variations, suggesting a causal role of the deleterious effects of genetic imbalance.
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| 6. |
- Pfeiffer, Dorothea, et al.
(författare)
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Professor Frieder Scheller turns 60
- 2002
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Ingår i: Biosensors & bioelectronics. - : Elsevier. - 0956-5663 .- 1873-4235. ; 17:11-12, s. 911-912
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Pfeiffer, Dorothea, et al.
(författare)
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The mu TPC method: improving the position resolution of neutron detectors based on MPGDs
- 2015
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Ingår i: Journal of Instrumentation. - : IOP Publishing: Hybrid Open Access. - 1748-0221. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Due to the He-3 crisis, alternatives to the standard neutron detection techniques are becoming urgent. In addition, the instruments of the European Spallation Source (ESS) require advances in the state of the art of neutron detection. The instruments need detectors with excellent neutron detection efficiency, high rate capabilities and unprecedented spatial resolution. The Macromolecular Crystallography instrument (NMX) requires a position resolution in the order of 200 mu m over a wide angular range of incoming neutrons. Solid converters in combination with Micro Pattern Gaseous Detectors (MPGDs) are proposed to meet the new requirements. Charged particles rising from the neutron capture have usually ranges larger than several millimetres in gas. This is apparently in contrast with the requirements for the position resolution. In this paper, we present an analysis technique, new in the field of neutron detection, based on the Time Projection Chamber (TPC) concept. Using a standard Single-GEM with the cathode coated with (B4C)-B-10, we extract the neutron interaction point with a resolution of better than sigma = 200 mu m.
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| 8. |
- Renneberg, Reinhard, et al.
(författare)
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Frieder scheller and the short history of biosensors
- 2008
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Ingår i: Advances in Biochemical Engineering/Biotechnology. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 0724-6145 .- 1616-8542. - 9783540752004 ; 109, s. 1-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This is a first attempt at a brief sketch of the history of biosensors. It is far from complete and rather unsystematic. Many names are still missing, and we apologize for this. But the authors hope to have laid a humble cornerstone for a future "Complete History of Biosensors". We hope that many of our colleagues will contribute!
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