| 1. |
|
|
| 2. |
- Dickson, L. T., et al.
(författare)
-
Mechanisms to control laser-plasma coupling in laser wakefield electron acceleration
- 2022
-
Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 25:10
-
Tidskriftsartikel (refereegranskat)abstract
- Experimental results, supported by precise modeling, demonstrate optimization of a plasma-based injector with intermediate laser pulse energy (<1 J), corresponding to a normalized vector potential a0=2.15, using ionization injection in a tailored plasma density profile. An increase in electron bunch quality and energy is achieved experimentally with the extension of the density downramp at the plasma exit. Optimization of the focal position of the laser pulse in the tailored plasma density profile is shown to efficiently reduce electron bunch angular deviation, leading to a better alignment of the electron bunch with the laser axis. Single peak electron spectra are produced in a previously unexplored regime by combining an early focal position and adaptive optic control of the laser wavefront by optimizing the symmetry of the prefocal laser energy distribution. Experimental results have been validated through particle-in-cell simulations using realistic laser energy, phase distribution, and temporal envelope, allowing for accurate predictions of difficult to model parameters, such as total charge and spatial properties of the electron bunches, opening the way for more accurate modeling for the design of plasma-based accelerators.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Babst, F., et al.
(författare)
-
When tree rings go global: Challenges and opportunities for retro- and prospective insight
- 2018
-
Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 197, s. 1-20
-
Tidskriftsartikel (refereegranskat)abstract
- The demand for large-scale and long-term information on tree growth is increasing rapidly as environmental change research strives to quantify and forecast the impacts of continued warming on forest ecosystems. This demand, combined with the now quasi-global availability of tree-ring observations, has inspired researchers to compile large tree-ring networks to address continental or even global-scale research questions. However, these emergent spatial objectives contrast with paleo-oriented research ideas that have guided the development of many existing records. A series of challenges related to how, where, and when samples have been collected is complicating the transition of tree rings from a local to a global resource on the question of tree growth. Herein, we review possibilities to scale tree-ring data (A) from the sample to the whole tree, (B) from the tree to the site, and (C) from the site to larger spatial domains. Representative tree-ring sampling supported by creative statistical approaches is thereby key to robustly capture the heterogeneity of climate-growth responses across forested landscapes. We highlight the benefits of combining the temporal information embedded in tree rings with the spatial information offered by forest inventories and earth observations to quantify tree growth and its drivers. In addition, we show how the continued development of mechanistic tree-ring models can help address some of the non-linearities and feedbacks that complicate making inference from tree-ring data. By embracing scaling issues, the discipline of dendrochronology will greatly increase its contributions to assessing climate impacts on forests and support the development of adaptation strategies. © 2018 Elsevier Ltd
|
|
| 6. |
|
|
| 7. |
- Hagell, Peter, et al.
(författare)
-
Sequential bilateral transplantation in Parkinson's disease: effects of the second graft
- 1999
-
Ingår i: Brain. - : Oxford University Press (OUP). - 1460-2156. ; 122:6, s. 1121-1132
-
Tidskriftsartikel (refereegranskat)abstract
- Five parkinsonian patients who had received implants of human embryonic mesencephalic tissue unilaterally in the striatum 10-56 months earlier were grafted with tissue from four to eight donors into the putamen (four patients) or the putamen plus the caudate nucleus (one patient) on the other side, and were followed for 18-24 months. After 12-18 months, PET showed a mean 85% increase in 6-L-[18F]fluorodopa uptake in the putamen with the second graft, whereas there was no significant further change in the previously transplanted putamen. Two patients exhibited marked additional improvements after their second graft: 'on-off' fluctuations virtually disappeared, movement speed increased, and L-dopa could be withdrawn in one patient and reduced by 70% in the other. The improvement in one patient was moderate. Two patients with atypical features, who responded poorly to the first graft, worsened following the second transplantation. These findings indicate that sequential transplantation in patients does not compromise the survival and function of either the first or the second graft. Moreover, putamen grafts that restore fluorodopa uptake to normal levels can give improvements of major therapeutic value.
|
|
| 8. |
- Horger, B A, et al.
(författare)
-
Neurturin exerts potent actions on survival and function of midbrain dopaminergic neurons
- 1998
-
Ingår i: The Journal of Neuroscience. - 1529-2401. ; 18:13, s. 4929-4937
-
Tidskriftsartikel (refereegranskat)abstract
- Glial cell line-derived neurotrophic factor (GDNF) exhibits potent effects on survival and function of midbrain dopaminergic (DA) neurons in a variety of models. Although other growth factors expressed in the vicinity of developing DA neurons have been reported to support survival of DA neurons in vitro, to date none of these factors duplicate the potent and selective actions of GDNF in vivo. We report here that neurturin (NTN), a homolog of GDNF, is expressed in the nigrostriatal system, and that NTN exerts potent effects on survival and function of midbrain DA neurons. Our findings indicate that NTN mRNA is sequentially expressed in the ventral midbrain and striatum during development and that NTN exhibits survival-promoting actions on both developing and mature DA neurons. In vitro, NTN supports survival of embryonic DA neurons, and in vivo, direct injection of NTN into the substantia nigra protects mature DA neurons from cell death induced by 6-OHDA. Furthermore, administration of NTN into the striatum of intact adult animals induces behavioral and biochemical changes associated with functional upregulation of nigral DA neurons. The similarity in potency and efficacy of NTN and GDNF on DA neurons in several paradigms stands in contrast to the differential distribution of the receptor components GDNF Family Receptor alpha1 (GFRalpha1) and GFRalpha2 within the ventral mesencephalon. These results suggest that NTN is an endogenous trophic factor for midbrain DA neurons and point to the possibility that GDNF and NTN may exert redundant trophic influences on nigral DA neurons acting via a receptor complex that includes GFRalpha1.
|
|
| 9. |
|
|
| 10. |
- Kirik, Deniz, et al.
(författare)
-
Parkinson-like neurodegeneration induced by targeted overexpression of alpha-synuclein in the nigrostriatal system
- 2002
-
Ingår i: The Journal of Neuroscience. - 1529-2401. ; 22:7, s. 2780-2791
-
Tidskriftsartikel (refereegranskat)abstract
- Recombinant adeno-associated viral vectors display efficient tropism for transduction of the dopamine neurons of the substantia nigra. Taking advantage of this unique property of recombinant adeno-associated viral vectors, we expressed wildtype and A53T mutated human alpha-synuclein in the nigrostriatal dopamine neurons of adult rats for up to 6 months. Cellular and axonal pathology, including alpha-synuclein-positive cytoplasmic inclusions and swollen, dystrophic neurites similar to those seen in brains from patients with Parkinson's disease, developed progressively over time. These pathological alterations occurred preferentially in the nigral dopamine neurons and were not observed in other nondopaminergic neurons transduced by the same vectors. The degenerative changes were accompanied by a loss of 30-80% of the nigral dopamine neurons, a 40-50% reduction of striatal dopamine, and tyrosine hydroxylase levels that was fully developed by 8 weeks. Significant motor impairment developed in those animals in which dopamine neuron cell loss exceeded a critical threshold of 50-60%. At 6 months, signs of cell body and axonal pathology had subsided, suggesting that the surviving neurons had recovered from the initial insult, despite the fact that alpha-synuclein expression was maintained at a high level. These results show that nigral dopamine neurons are selectively vulnerable to high levels of either wild-type or mutant alpha-synuclein, pointing to a key role for alpha-synuclein in the pathogenesis of Parkinson's disease. Targeted overexpression of alpha-synuclein in the nigrostriatal system may provide a new animal model of Parkinson's disease that reproduces some of the cardinal pathological, neurochemical, and behavioral features of the human disease.
|
|
| 11. |
- Klimovich, Alexander, et al.
(författare)
-
Prototypical pacemaker neurons interact with the resident microbiota
- 2020
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:30, s. 17854-17863
-
Tidskriftsartikel (refereegranskat)abstract
- Pacemaker neurons exert control over neuronal circuit function by their intrinsic ability to generate rhythmic bursts of action potential. Recent work has identified rhythmic gut contractions in human, mice, and hydra to be dependent on both neurons and the resident microbiota. However, little is known about the evolutionary origin of these neurons and their interaction with microbes. In this study, we identified and functionally characterized prototypical ANO/SCN/TRPMion channel-expressing pacemaker cells in the basal metazoan Hydra by using a combination of single-cell transcriptomics, immunochemistry, and functional experiments. Unexpectedly, these prototypical pacemaker neurons express a rich set of immune-related genes mediating their interaction with the microbial environment. Furthermore, functional experiments gave a strong support to a model of the evolutionary emergence of pacemaker cells as neurons using components of innate immunity to interact with the microbial environment and ion channels to generate rhythmic contractions.
|
|
| 12. |
- Lindvall, O, et al.
(författare)
-
Evidence for long-term survival and function of dopaminergic grafts in progressive Parkinson's disease
- 1994
-
Ingår i: Annals of Neurology. - : Wiley. - 0364-5134. ; 35:2, s. 80-172
-
Tidskriftsartikel (refereegranskat)abstract
- Two patients with idiopathic Parkinson's disease (Patients 3 and 4 in our series) were followed up to 3 years after grafting of human embryonic dopamine-rich mesencephalic tissue unilaterally into the putamen. During the first postoperative year both patients showed significant amelioration of parkinsonian symptoms and increased 6-L-[18F]-fluorodopa uptake in the grafted putamen, as assessed with positron emission tomography. Three years after grafting the patients still exhibited increased fluorodopa uptake in the grafted putamen and significant clinical improvements, evidenced by a reduction of the severity of symptoms and of the time spent in the "off" phase, and by a prolongation of the effect of a single dose of L-dopa. Between 1 and 3 years after surgery, Patient 3 showed only minor changes of parkinsonian symptoms on the side contralateral to the graft, whereas there was a worsening on the ipsilateral side. Fluorodopa uptake decreased in the nongrafted putamen but was unchanged in the grafted putamen. Patient 4 continued to improve after the first postoperative year and L-dopa was withdrawn after 32 months. The reduction of parkinsonian symptoms on the side contralateral to the graft became more pronounced between 1 and 3 years after surgery. Fluorodopa uptake further increased in the grafted putamen, whereas no change was detected on the non-grafted side. These results indicate that grafts of embryonic dopamine neurons can survive, grow, and exert functional effects up to at least 3 years after surgery in the parkinsonian brain, despite an ongoing disease process leading to degeneration of the intrinsic dopamine system.
|
|
| 13. |
|
|
| 14. |
- Lindvall, O, et al.
(författare)
-
Human fetal dopamine neurons grafted into the striatum in two patients with severe Parkinson's disease. A detailed account of methodology and a 6-month follow-up
- 1989
-
Ingår i: Archives of Neurology. - : American Medical Association (AMA). - 0003-9942. ; 46:6, s. 31-615
-
Tidskriftsartikel (refereegranskat)abstract
- By using stereotaxic surgical techniques, ventral mesencephalic tissues from aborted human fetuses of 8 to 10 weeks' gestational age were implanted unilaterally into the striata in two patients with advanced Parkinson's disease. The patients were treated with a cyclosporine, azathioprine, and steroid regimen to minimize the risk for graft rejection. They were examined for 6 months preoperatively and 6 months postoperatively and continued to receive the same doses of antiparkinsonian medication. There were no significant postoperative complications. No major therapeutic effect from the operation was observed. However, in the clinical tests, both patients showed small but significant increases of movement speed for repeated pronation-supination, fist clenching, and foot lifting. The rate of walking also increased in the one patient tested. For both patients, there was an initial worsening postoperatively, followed by improvement vs preoperative performance at 1 to 3 months. Both patients also showed significant improvement in the magnitude of response to a single dose of levodopa (L-dopa), but there was no increase in the duration of drug action. The motor readiness potential increased in both patients postoperatively, primarily over the operated hemisphere. Neurophysiological measurements also showed a more rapid performance of simple and complex arm and hand movements on the side contralateral to transplantation in one patient at 5 months postoperatively. Positron emission tomography demonstrated no increased uptake of 6-L-(18F)-fluorodopa in the transplanted striatum at 5 and 6 months. Taken together, these results suggest that the fetal nigral implants may have provided a modest improvement in motor function, consistent with the presence of small surviving grafts. Although our results support further scientific experimentation with transplantation in Parkinson's disease, widespread clinical trials with this procedure are probably not warranted at this time.
|
|
| 15. |
- Lindvall, O, et al.
(författare)
-
In reply : Fetal brain grafts and Parkinson's disease
- 1990
-
Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 250:4986, s. 1435-1435
-
Tidskriftsartikel (refereegranskat)
|
|
| 16. |
- Nunes, A. K. D., et al.
(författare)
-
Sildenafil (Viagra (R)) prevents and restores LPS-induced inflammation in astrocytes
- 2016
-
Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 630, s. 59-65
-
Tidskriftsartikel (refereegranskat)abstract
- Astrocytes are effectively involved in the pathophysiological processes in the central nervous system (CNS) and may contribute to or protect against development of inflammatory and degenerative diseases. Sildenafil is a potent and selective phosphodiesterase-5 (PDE-5) inhibitor, which induces cyclic GMP accumulation. However, the mechanisms of actions on glial cells are not clear. The aim of the present work is to evaluate the role of sildenafil in lipopolysaccharide (LPS)-stimulated astrocytes. The cytoskeleton integrity and Ca2+ waves were assessed as indicators of inflammatory state. Two main groups were done: (A) one prevention and (B) one restoration. Each of these groups: A1: control; A2: LPS for 24h; A3: sildenafil 1 or 10 mu M for 4h and then sildenafil 1 or 10 mu M + LPS for 24 h. B1: control; B2: LPS for 24 h; B3: LPS for 24 h and then LPS + sildenafil 1 or 10 mu M for 24 h. Cytoskeleton integrity was analyzed through GFAP immunolabeling and actin labeling with an Alexa 488-conjugated phalloidin probe. Calcium responses were assessed through a Ca2+-sensitive fluorophore Fura-2/AM. The results show that both preventive and restorative treatments with sildenafil (in both concentrations) reduced the Ca2+ responses in intensity and induced a more organized actin fiber pattern, compared to LPS treated cells. This work demonstrated for the first time that astrocytes are a key part of the sildenafil protective effects in the CNS.
|
|
| 17. |
- Pallaroni, L, et al.
(författare)
-
Microwave-assisted extraction of zearalenone from wheat and corn
- 2002
-
Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 374:1, s. 161-166
-
Tidskriftsartikel (refereegranskat)abstract
- A microwave-assisted extraction (MAE) method has been developed for determination of zearalenone in wheat and corn by LC-MS with an atmospheric pressure chemical ionization interface (APCI). Matrix effects were minimized by use of matrix-matched standard curves for quantification of the analyte. The limit of quantification (LOQ) of the method was 30 ng g(-1) in wheat and 20 ng g(-1) in corn. The rapid LC-MS method enabled analysis of the extracts without clean-up, thereby reducing analyte losses, the time required for the analytical procedure, and costs. A factorial design approach was used to examine the effect on extraction efficiency of the main extraction conditions - time, temperature, and solvent. On the basis of results from statistical assessment extraction was performed with 1:1 (v/v) methanol-acetonitrile at 80degreesC for 5 min. When these extraction conditions were applied to a wheat sample from a recently conducted international proficiency test, 92% (103 ng g(-1)) of the assigned zearalenone concentration (112 ng g(-1)) in the test material was obtained. This result was within the uncertainty (u) range of the assigned value of the test material (u = +/-15.8 ng g(-1), alpha = 0.05) thereby demonstrating the accuracy of the method was sufficient. The precision of the whole method was also confirmed to be adequate, because the observed relative standard deviation (RSD) of 12% (n = 10) also fulfils the quality criteria recommended by European guidelines for in-house method validation.
|
|
| 18. |
- Pramling, Niklas, 1973, et al.
(författare)
-
The Letter Thief: From Playing to Teaching to Learning to Playing
- 2019
-
Ingår i: Play-Responsive Teaching in Early Childhood Education. - Cham : Springer International Publishing. - 2468-8746.
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter, we show how a learning content can be introduced in a child-initiated play frame, without interrupting the play. The chapter therefore gives an example of how what is sometimes referred to as academic content can be promoted through such activity. The analysis clarifies how reading and graphical symbols become structuring resources in children’s play. A real-world problem (as is) is introduced and managed within the fictional realm of play (as if). © 2019, The Author(s).
|
|
| 19. |
- Wenning, Gregor K, et al.
(författare)
-
Short- and long-term survival and function of unilateral intrastriatal dopaminergic grafts in Parkinson's disease
- 1997
-
Ingår i: Annals of Neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 42:1, s. 95-107
-
Tidskriftsartikel (refereegranskat)abstract
- Six patients with Parkinson's disease were followed for 10 to 72 months after human embryonic mesencephalic tissue from four to seven donors was grafted unilaterally into the putamen (4 patients) or putamen plus caudate (2 patients). After 8 to 12 months, positron emission tomography showed a 68% increase of 6-L-[18F]-fluorodopa uptake in the grafted putamen, no change in the grafted caudate, and minor decreases in nongrafted striatal regions. There was therapeutically valuable improvement in 4 patients, but only modest changes in the other 2, both of whom developed atypical features. Patient 4 was without L-dopa from 32 months and had normal fluorodopa uptake in the grafted putamen at 72 months. Overall, the L-dopa dose was reduced by a mean of 10 and 20%, "off" time was reduced by 34 and 44%, and the "off" phase Unified Parkinson's Disease Rating Scale motor score by 18 and 26%, and the duration of the response to a single L-dopa dose increased by 45 and 58% during the first and second years after surgery, respectively. Rigidity and hypokinesia improved bilaterally, but mainly contralateral to the implant. No consistent changes in dyskinesias were observed. We conclude that transplantation of embryonic mesencephalic tissue leads to highly reproducible survival of dopaminergic neurons, inducing clinically valuable improvements in most recipients.
|
|
| 20. |
|
|
| 21. |
- Adli, Erik, et al.
(författare)
-
Progress Of The Ess Proton Beam Imaging Systems
- 2022
-
Ingår i: LINAC2022. - : ACoW Publishing. ; , s. 395-398
-
Konferensbidrag (refereegranskat)abstract
- The ESS Target Proton Beam Imaging Systems has the objective to image the 5 MW ESS proton beam as it entersthe spallation target. The imaging systems has to operate in a harsh radiation environment, leading to a number of challenges : development of radiation hard photon sources, long and aperture-restricted optical paths and fast electronics required to provide rapid information in case of beam anomalies. This paper outlines how main challenges of the imaging systems have been addressed, and the status of deployment as ESS gets closer to beam.
|
|
| 22. |
- Alexanderson, H., et al.
(författare)
-
FATIGUE IN ADULT IDIOPATHIC INFLAMMATORY MYOPATHIES
- 2015
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ PUBLISHING GROUP. - 0003-4967 .- 1468-2060. ; 74, s. 106-106
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
- Arapovic-Johansson, B., et al.
(författare)
-
Work-related stress assessed by a text message single-item stress question
- 2017
-
Ingår i: Occupational Medicine. - : OXFORD UNIV PRESS. - 0962-7480 .- 1471-8405. ; 67:8, s. 601-608
-
Tidskriftsartikel (refereegranskat)abstract
- Background Given the prevalence of work stress-related ill-health in the Western world, it is important to find cost-effective, easy-to-use and valid measures which can be used both in research and in practice. Aims To examine the validity and reliability of the single-item stress question (SISQ), distributed weekly by short message service (SMS) and used for measurement of work-related stress. Methods The convergent validity was assessed through associations between the SISQ and subscales of the Job Demand-Control-Support model, the Effort-Reward Imbalance model and scales measuring depression, exhaustion and sleep. The predictive validity was assessed using SISQ data collected through SMS. The reliability was analysed by the test-retest procedure. Results Correlations between the SISQ and all the subscales except for job strain and esteem reward were significant, ranging from -0.186 to 0.627. The SISQ could also predict sick leave, depression and exhaustion at 12-month follow-up. The analysis on reliability revealed a satisfactory stability with a weighted kappa between 0.804 and 0.868. Conclusions The SISQ, administered through SMS, can be used for the screening of stress levels in a working population.
|
|
