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| 4. |
- Bobek, Thomas, et al.
(författare)
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Self-organized hexagonal patterns of independent magnetic nanodots
- 2007
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 19:24, s. 4375-
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Tidskriftsartikel (refereegranskat)abstract
- A method for producing self-organised arrays of nanometric metallic dots is reported. It consists on developing first the nanodot pattern by ion erosion on a semiconductor cover film and transferring it to a previously buried metallic layer. This procedure has been applied to Co, and the ferromagnetic behaviour of the dots at room temperature is demonstrated.
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| 5. |
- Jesus Luque, Francisco, et al.
(författare)
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Magnetic ordering in an (Fe0.2Cr0.8)(1.5)[Cr(CN)(6)] Prussian blue analogue studied with synchrotron radiation based spectroscopies
- 2018
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 6:30, s. 8171-8186
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Tidskriftsartikel (refereegranskat)abstract
- The appearance of magnetic order in the (Fe0.2Cr0.8)(1.5)[Cr(CN)(6)]center dot 15H(2)O Prussian blue analogue at low temperature has been investigated by means of synchrotron radiation-based X-ray absorption spectroscopy and X-ray magnetic circular dichroism. With the help of ligand field multiplet analysis we have been able to identify the oxidation states of the metallic cations present in the sample and their evolution with temperature. Our experiments reveal that the appearance of ferromagnetic order is triggered by the transformation of Cr-III cations to Cr-II high-spin caused by a transfer of electrons from the Fe to the Cr resulting in an increase of the magnetic interactions within the (Cr, Cr) sublattice. The misfit strain between the (Fe, Cr) and the (Cr, Cr) moieties that coexist within this ternary material influences the balance of oxidation states and hence the magnetic properties of the metallic ions. Misfit relaxation also plays a role in determining the differences between the surface and the bulk of the material. The measurement of the magnetic moments in those two regions suggests that the surface may have a reduced Curie temperature compared to the bulk.
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| 6. |
- Jesus Luque, Francisco, et al.
(författare)
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Photoinduced effects on the magnetic properties of the ( Fe0.2Cr0.8) 1.5[ Cr( CN) 6] Prussian blue analogue
- 2019
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 7:8, s. 2305-2317
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Tidskriftsartikel (refereegranskat)abstract
- One of the most attractive characteristics of some Prussian blue derivatives is the sensitivity of their magnetic properties to the irradiation with light. In this work photoinduced effects in the (Fe0.2Cr0.8)(1.5)[Cr(CN)(6)]15H(2)O PBA have been studied by means of X-ray-based spectroscopies and magnetometry. It is found that the photosensitivity of this compound is mostly centred on the Fe cations: the exposure to green light induces a transfer of electrons from them to the Cr that provokes a reversal of the previously existing linkage isomerization and increases the elastic strain caused by the misfit of the unit cells of the Fe-NC-Cr and Cr-NC-Cr sublattices. The green light also quenches the magnetism of the Fe-II high-spin (HS) ions present in the sample and reduces the magnetic moments of most of the Cr cations except for Cr-II HS. Our study highlights the important role played by the mismatch between the unit cells of the coexisting sub-lattices in ternary Prussian blue analogues.
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| 7. |
- Khatri, C, et al.
(författare)
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Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study
- 2021
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Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:11, s. e050830-
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Tidskriftsartikel (refereegranskat)abstract
- Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis.SettingProspective, international, multicentre, observational cohort study.ParticipantsPatients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative).Primary outcome30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality.ResultsThis study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p<0.001), age >80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787).ConclusionsPatients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups.Trial registration numberNCT04323644
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| 8. |
- Miranda, Miguel, et al.
(författare)
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All-optical measurement of the complete waveform of octave-spanning ultrashort light pulses
- 2019
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Ingår i: Optics Letters. - 0146-9592. ; 44:2, s. 191-194
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the complete temporal characterization of the optical waveform of visible near-infrared octave-spanning ultrashort laser pulses, using an all-optical, all-solid-state, and fully inline dispersion-scan device based only on second-harmonic generation.
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| 9. |
- Nishi, Stephanie K., et al.
(författare)
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Mediterranean, DASH, and MIND Dietary Patterns and Cognitive Function : The 2-Year Longitudinal Changes in an Older Spanish Cohort
- 2021
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media SA. - 1663-4365. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims: Plant-forward dietary patterns have been associated with cardiometabolic health benefits, which, in turn, have been related to cognitive performance with inconsistent findings. The objective of this study was to examine the relationship between baseline adherence to three a priori dietary patterns (Mediterranean, DASH, and MIND diets) with 2-year changes in cognitive performance in older adults with overweight or obesity and high cardiovascular disease risk. Methods: A prospective cohort analysis was conducted within the PREDIMED-Plus trial, involving 6,647 men and women aged 55–75 years with overweight or obesity and metabolic syndrome. Using a validated, semiquantitative 143-item food frequency questionnaire completed at baseline, the dietary pattern adherence scores were calculated. An extensive neuropsychological test battery was administered at baseline and 2-year follow-up. Multivariable-adjusted linear regression models were used to assess associations between 2-year changes in cognitive function z-scores across tertiles of baseline adherence to the a priori dietary patterns. Results: Adherence to the Mediterranean diet at baseline was associated with 2-year changes in the general cognitive screening Mini-Mental State Examination (MMSE, β: 0.070; 95% CI: 0.014, 0.175, P-trend = 0.011), and two executive function-related assessments: the Trail Making Tests Part A (TMT-A, β: −0.054; 95% CI: −0.110, − 0.002, P-trend = 0.047) and Part B (TMT-B, β: −0.079; 95% CI: −0.134, −0.024, P-trend = 0.004). Adherence to the MIND diet was associated with the backward recall Digit Span Test assessment of working memory (DST-B, β: 0.058; 95% CI: 0.002, 0.114, P-trend = 0.045). However, higher adherence to the DASH dietary pattern was not associated with better cognitive function over a period of 2 years. Conclusion: In older Spanish individuals with overweight or obesity and at high cardiovascular disease risk, higher baseline adherence to the Mediterranean dietary pattern may be associated with better cognitive performance than lower adherence over a period of 2 years.
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| 11. |
- Sánchez Van Kammen, Mayte, et al.
(författare)
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Characteristics and Outcomes of Patients with Cerebral Venous Sinus Thrombosis in SARS-CoV-2 Vaccine-Induced Immune Thrombotic Thrombocytopenia
- 2021
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Ingår i: JAMA Neurology. - : American Medical Association. - 2168-6149 .- 2168-6157. ; 78:11, s. 1314-1323
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Thrombosis with thrombocytopenia syndrome (TTS) has been reported after vaccination with the SARS-CoV-2 vaccines ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson).Objective: To describe the clinical characteristics and outcome of patients with cerebral venous sinus thrombosis (CVST) after SARS-CoV-2 vaccination with and without TTS.Design, Setting, and Participants: This cohort study used data from an international registry of consecutive patients with CVST within 28 days of SARS-CoV-2 vaccination included between March 29 and June 18, 2021, from 81 hospitals in 19 countries. For reference, data from patients with CVST between 2015 and 2018 were derived from an existing international registry. Clinical characteristics and mortality rate were described for adults with (1) CVST in the setting of SARS-CoV-2 vaccine-induced immune thrombotic thrombocytopenia, (2) CVST after SARS-CoV-2 vaccination not fulling criteria for TTS, and (3) CVST unrelated to SARS-CoV-2 vaccination.Exposures: Patients were classified as having TTS if they had new-onset thrombocytopenia without recent exposure to heparin, in accordance with the Brighton Collaboration interim criteria.Main Outcomes and Measures: Clinical characteristics and mortality rate.Results: Of 116 patients with postvaccination CVST, 78 (67.2%) had TTS, of whom 76 had been vaccinated with ChAdOx1 nCov-19; 38 (32.8%) had no indication of TTS. The control group included 207 patients with CVST before the COVID-19 pandemic. A total of 63 of 78 (81%), 30 of 38 (79%), and 145 of 207 (70.0%) patients, respectively, were female, and the mean (SD) age was 45 (14), 55 (20), and 42 (16) years, respectively. Concomitant thromboembolism occurred in 25 of 70 patients (36%) in the TTS group, 2 of 35 (6%) in the no TTS group, and 10 of 206 (4.9%) in the control group, and in-hospital mortality rates were 47% (36 of 76; 95% CI, 37-58), 5% (2 of 37; 95% CI, 1-18), and 3.9% (8 of 207; 95% CI, 2.0-7.4), respectively. The mortality rate was 61% (14 of 23) among patients in the TTS group diagnosed before the condition garnered attention in the scientific community and 42% (22 of 53) among patients diagnosed later.Conclusions and Relevance: In this cohort study of patients with CVST, a distinct clinical profile and high mortality rate was observed in patients meeting criteria for TTS after SARS-CoV-2 vaccination..
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| 12. |
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| 13. |
- Ahnen, M. L., et al.
(författare)
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Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies
- 2016
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :2
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Tidskriftsartikel (refereegranskat)abstract
- We present the first joint analysis of gamma-ray data from the MAGIC Cherenkov telescopes and the Fermi Large Area Telescope (LAT) to search for gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We combine 158 hours of Segue 1 observations with MAGIC with 6-year observations of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the annihilation cross-section for dark matter particle masses between 10 GeV and 100 TeV - the widest mass range ever explored by a single gamma-ray analysis. These limits improve on previously published Fermi-LAT and MAGIC results by up to a factor of two at certain masses. Our new inclusive analysis approach is completely generic and can be used to perform a global, sensitivity-optimized dark matter search by combining data from present and future gamma-ray and neutrino detectors.
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| 14. |
- Alonso, Benjamin, et al.
(författare)
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Characterization of sub-two-cycle pulses from a hollow-core fiber compressor in the spatiotemporal and spatiospectral domains
- 2013
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 112:1, s. 105-114
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Tidskriftsartikel (refereegranskat)abstract
- We have post-compressed 25 fs (Fourier limit) amplified pulses in an argon-filled hollow-core fiber. The output pulses were compressed using a pair of wedges and chirped mirrors down to 4.5 fs (Fourier limit of 4.1 fs), which corresponds to less than two optical cycles. We then performed the characterization of the pulses by combining the d-scan and the STARFISH techniques. The temporal (and spectral) measurement of the pulses is done with d-scan, which is used as the reference to extend the characterization to the spatiotemporal (and spatiospectral) amplitude and phase of the pulses by means of STARFISH. The post-compressed pulses at the output of the hollow-fiber had an energy of 150 mu J. The analysis of the pulses revealed larger spectral broadening and blue-shift, and shorter duration at the center of the beam. For the first time, we demonstrate the complete characterization of intense ultra-broadband pulses in the sub-two-cycle regime, which provides an improved insight into the properties (space-time and space-frequency) of the pulses and is highly relevant for their applications.
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| 15. |
- Berrocal, Edouard, et al.
(författare)
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Two-photon fluorescence laser sheet imaging for high contrast visualization of atomizing sprays
- 2019
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Ingår i: OSA Continuum. - 2578-7519. ; 2:3, s. 983-993
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon excitation laser induced fluorescence (2p-LIF) is used here for imaging an optically dense atomizing spray. The main advantage of the approach is that very little fluorescence interference originating from multiple light scattering is generated. This leads to high image contrast and a faithful description of the imaged fluid structures. While point measurement 2p-LIF imaging is a well-known approach used in life science microscopy, it has, to the best of the authors' knowledge, never been tested for analyzing liquid structures in spray systems. We take advantage of this process, here, at a macroscopic scale (textblackslashsim 5textblackslashtimes 5$5texttimes5 mm field of view) by imaging the central part of a light sheet of 10 mm height. To generate enough 2p-LIF signal at such a scale and with single-shot detection, ultra-short laser pulses of 25 fs, centered at 800 nm wavelength and having 2.5 mJ pulse energy, have been used. The technique is demonstrated by imaging a single spray plume from a 6 hole commercial Gasoline Direct Injection (GDI) system running at 200 bar injection pressure. The proposed approach is very promising for detailed analysis of liquid breakups in optically dense sprays and can be used for other fluid mechanics related applications.
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| 16. |
- Best, Mairi, et al.
(författare)
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EMSO: A distributed infrastructure for addressing geohazards and global ocean change
- 2014
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Ingår i: Oceanography. - : The Oceanography Society. - 1042-8275. ; 27:2, s. 167-169
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Tidskriftsartikel (refereegranskat)abstract
- The European Multidisciplinary Seafloor and water-column Observatory (EMSO; http://www.emso-eu.org) is addressing the next challenge in Earth-ocean science: how to coordinate data acquisition, analysis, archiving, access, and response to geohazards across provincial, national, regional, and international boundaries. Such coordination is needed to optimize the use of current and planned ocean observatory systems to (1) address national and regional public safety concerns about geohazards (e.g., earthquakes, submarine landslides, tsunamis) and (2) permit broadening of their scope toward monitoring environmental change on global ocean scales.
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| 17. |
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| 18. |
- Boehle, Frederik, et al.
(författare)
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Compression of CEP-stable multi-mJ laser pulses down to 4 fs in long hollow fibers
- 2014
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Ingår i: Laser Physics Letters. - : IOP Publishing. - 1612-2011 .- 1612-202X. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- Carrier-envelope phase stable 4 fs near-IR pulses with 3 mJ energy were generated by spectral broadening of circularly polarized 8 mJ pulses in a differentially pumped 2 m long composite stretched flexible hollow fiber. The pulses were characterized using both second-harmonic generation frequency-resolved optical gating (SHG-FROG) and SHG d-scan methods.
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| 19. |
- Campi, Filippo, et al.
(författare)
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Design and test of a broadband split-and-delay unit for attosecond XUV-XUV pump-probe experiments.
- 2016
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 87:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the design of a split-and-delay unit for the production of two delayed replicas of an incident extreme ultraviolet (XUV) pulse. The device features a single grazing incidence reflection in combination with attenuation of remaining infrared light co-propagating with the XUV beam, offering a high throughput without the need of introducing additional optics that would further decrease the XUV flux. To achieve the required spatial and temporal stabilities, the device is controlled by two PID-controllers monitoring the delay and the beam pointing using an optical reference laser beam, making collimation of the beam by additional optics unnecessary. Finally, we demonstrate the stability of the split-and-delay unit by performing all-reflective autocorrelation measurements on broadband few-cycle laser pulses.
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| 20. |
- Cheng, Yu Chen, et al.
(författare)
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Controlling photoionization using attosecond time-slit interferences
- 2020
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 117:20, s. 10727-10732
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Tidskriftsartikel (refereegranskat)abstract
- When small quantum systems, atoms or molecules, absorb a high-energy photon, electrons are emitted with a well-defined energy and a highly symmetric angular distribution, ruled by energy quantization and parity conservation. These rules are based on approximations and symmetries which may break down when atoms are exposed to ultrashort and intense optical pulses. This raises the question of their universality for the simplest case of the photoelectric effect. Here we investigate photoionization of helium by a sequence of attosecond pulses in the presence of a weak infrared laser field. We continuously control the energy of the photoelectrons and introduce an asymmetry in their emission direction, at variance with the idealized rules mentioned above. This control, made possible by the extreme temporal confinement of the light-matter interaction, opens a road in attosecond science, namely, the manipulation of ultrafast processes with a tailored sequence of attosecond pulses.
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| 23. |
- Diogenes, Maria Jose, et al.
(författare)
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Extracellular Alpha-Synuclein Oligomers Modulate Synaptic Transmission and Impair LTP Via NMDA-Receptor Activation
- 2012
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Ingår i: Journal of Neuroscience. - 0270-6474 .- 1529-2401. ; 32:34, s. 11750-11762
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Tidskriftsartikel (refereegranskat)abstract
- Parkinson's disease (PD) is the most common representative of a group of disorders known as synucleinopathies, in which misfolding and aggregation of alpha-synuclein (a-syn) in various brain regions is the major pathological hallmark. Indeed, the motor symptoms in PD are caused by a heterogeneous degeneration of brain neurons not only in substantia nigra pars compacta but also in other extrastriatal areas of the brain. In addition to the well known motor dysfunction in PD patients, cognitive deficits and memory impairment are also an important part of the disorder, probably due to disruption of synaptic transmission and plasticity in extrastriatal areas, including the hippocampus. Here, we investigated the impact of a-syn aggregation on AMPA and NMDA receptor-mediated rat hippocampal (CA3-CA1) synaptic transmission and long-term potentiation (LTP), the neurophysiological basis for learning and memory. Our data show that prolonged exposure to a-syn oligomers, but not monomers or fibrils, increases basal synaptic transmission through NMDA receptor activation, triggering enhanced contribution of calcium-permeable AMPA receptors. Slices treated with a-syn oligomers were unable to respond with further potentiation to theta-burst stimulation, leading to impaired LTP. Prior delivery of a low-frequency train reinstated the ability to express LTP, implying that exposure to a-syn oligomers drives the increase of glutamatergic synaptic transmission, preventing further potentiation by physiological stimuli. Our novel findings provide mechanistic insight on how a-syn oligomers may trigger neuronal dysfunction and toxicity in PD and other synucleinopathies.
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| 24. |
- Ellervee, Peeter, et al.
(författare)
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Exploiting data transfer locality in memory mapping
- 1999
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Ingår i: EUROMICRO Conference, 1999. Proceedings. 25th. ; , s. 14-21
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Konferensbidrag (refereegranskat)abstract
- System-level exploration of memory architectures is one of the key issues in successful implementation of data-transfer dominated applications. Usually, one of the main design bottlenecks is the memory access bandwidth. Transformations, rearranging the layout of the data records stored in memory, are very effective to improve the locality of the data transfers but usually lead to a large memory bit-wastage when not performed carefully. In this paper, a methodology which reduces memory bandwidth requirements without sacrificing storage space is proposed. The methodology exploits parallelism in the data-transfers to rearrange the layout of the data records. Distributed memory organization combined with our proposed layout rearrangement methodology allow to effectively reduce the memory bandwidth bottleneck in data-transfer dominated applications
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| 25. |
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