| 1. |
- Abreu, P., et al.
(författare)
-
Search for sleptons in e+e- collisions at √s = 183 to 189 GeV
- 2001
-
Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 19:1, s. 29-42
-
Tidskriftsartikel (refereegranskat)abstract
- Data taken by the DELPHI experiment at centre-of-mass energies of 183 GeV and 189 GeV with a total integrated luminosity of 212 pb-1 have been used to search for the supersymmetric partners of the electrons, muons, and taus in the context of the Minimal Supersymmetric Standard Model (MSSM). The decay topologies searched for were the direct decay (ℓ̃ → ℓx̃), producing acoplanar lepton pairs plus missing energy, and the cascade decay (ℓ → ℓx̃0 2 → ℓγx̃0 1), producing acoplanar lepton and photon pairs plus missing energy. The observed number of events is in agreement with Standard Model predictions. The 95% CL excluded mass limits for selectrons, smuons and staus are mẽ ≤ 87 GeV/c2, mμ̃ ≤ 80 GeV/c2 and mτ̃ 75 GeV/c2, respectively, for values of μ=-200 GeV/c2 and tanβ=1.5.
|
|
| 2. |
- Weiner, D. J., et al.
(författare)
-
Polygenic transmission disequilibrium confirms that common and rare variation act additively to create risk for autism spectrum disorders
- 2017
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 49:7
-
Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorder (ASD) risk is influenced by common polygenic and de novo variation. We aimed to clarify the influence of polygenic risk for ASD and to identify subgroups of ASD cases, including those with strongly acting de novo variants, in which polygenic risk is relevant. Using a novel approach called the polygenic transmission disequilibrium test and data from 6,454 families with a child with ASD, we show that polygenic risk for ASD, schizophrenia, and greater educational attainment is over-transmitted to children with ASD. These findings hold independent of proband IQ. We find that polygenic variation contributes additively to risk in ASD cases who carry a strongly acting de novo variant. Lastly, we show that elements of polygenic risk are independent and differ in their relationship with phenotype. These results confirm that the genetic influences on ASD are additive and suggest that they create risk through at least partially distinct etiologic pathways.
|
|
| 3. |
- Anney, R. J. L., et al.
(författare)
-
Meta-analysis of GWAS of over 16,000 individuals with autism spectrum disorder highlights a novel locus at 10q24.32 and a significant overlap with schizophrenia
- 2017
-
Ingår i: Molecular Autism. - : Springer Science and Business Media LLC. - 2040-2392. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Over the past decade genome-wide association studies (GWAS) have been applied to aid in the understanding of the biology of traits. The success of this approach is governed by the underlying effect sizes carried by the true risk variants and the corresponding statistical power to observe such effects given the study design and sample size under investigation. Previous ASD GWAS have identified genome-wide significant (GWS) risk loci; however, these studies were of only of low statistical power to identify GWS loci at the lower effect sizes (odds ratio (OR) < 1.15). Methods: We conducted a large-scale coordinated international collaboration to combine independent genotyping data to improve the statistical power and aid in robust discovery of GWS loci. This study uses genome-wide genotyping data from a discovery sample (7387 ASD cases and 8567 controls) followed by meta-analysis of summary statistics from two replication sets (7783 ASD cases and 11359 controls; and 1369 ASD cases and 137308 controls). Results: We observe a GWS locus at 10q24.32 that overlaps several genes including PITX3, which encodes a transcription factor identified as playing a role in neuronal differentiation and CUEDC2 previously reported to be associated with social skills in an independent population cohort. We also observe overlap with regions previously implicated in schizophrenia which was further supported by a strong genetic correlation between these disorders (Rg = 0.23; P= 9 x10(-6)). We further combined these Psychiatric Genomics Consortium (PGC) ASD GWAS data with the recent PGC schizophrenia GWAS to identify additional regions which may be important in a common neurodevelopmental phenotype and identified 12 novel GWS loci. These include loci previously implicated in ASD such as FOXP1 at 3p13, ATP2B2 at 3p25.3, and a 'neurodevelopmental hub' on chromosome 8p11.23. Conclusions: This study is an important step in the ongoing endeavour to identify the loci which underpin the common variant signal in ASD. In addition to novel GWS loci, we have identified a significant genetic correlation with schizophrenia and association of ASD with several neurodevelopmental- related genes such as EXT1, ASTN2, MACROD2, and HDAC4.
|
|
| 4. |
|
|
| 5. |
- Kupers, LK, et al.
(författare)
-
Meta-analysis of epigenome-wide association studies in neonates reveals widespread differential DNA methylation associated with birthweight
- 2019
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 1893-
-
Tidskriftsartikel (refereegranskat)abstract
- Birthweight is associated with health outcomes across the life course, DNA methylation may be an underlying mechanism. In this meta-analysis of epigenome-wide association studies of 8,825 neonates from 24 birth cohorts in the Pregnancy And Childhood Epigenetics Consortium, we find that DNA methylation in neonatal blood is associated with birthweight at 914 sites, with a difference in birthweight ranging from −183 to 178 grams per 10% increase in methylation (PBonferroni < 1.06 x 10−7). In additional analyses in 7,278 participants, <1.3% of birthweight-associated differential methylation is also observed in childhood and adolescence, but not adulthood. Birthweight-related CpGs overlap with some Bonferroni-significant CpGs that were previously reported to be related to maternal smoking (55/914, p = 6.12 x 10−74) and BMI in pregnancy (3/914, p = 1.13x10−3), but not with those related to folate levels in pregnancy. Whether the associations that we observe are causal or explained by confounding or fetal growth influencing DNA methylation (i.e. reverse causality) requires further research.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Pearce, Neil E, et al.
(författare)
-
IARC Monographs : 40 Years of Evaluating Carcinogenic Hazards to Humans
- 2015
-
Ingår i: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 123:6, s. 507-514
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recently the International Agency for Research on Cancer (IARC) Programme for the Evaluation of Carcinogenic Risks to Humans has been criticized for several of its evaluations, and also the approach used to perform these evaluations. Some critics have claimed that IARC Working Groups' failures to recognize study weaknesses and biases of Working Group members have led to inappropriate classification of a number of agents as carcinogenic to humans.OBJECTIVES: The authors of this paper are scientists from various disciplines relevant to the identification and hazard evaluation of human carcinogens. We have examined here criticisms of the IARC classification process to determine the validity of these concerns. We review the history of IARC evaluations and describe how the IARC evaluations are performed.DISCUSSION: We conclude that these recent criticisms are unconvincing. The procedures employed by IARC to assemble Working Groups of scientists from the various discipline and the techniques followed to review the literature and perform hazard assessment of various agents provide a balanced evaluation and an appropriate indication of the weight of the evidence. Some disagreement by individual scientists to some evaluations is not evidence of process failure. The review process has been modified over time and will undoubtedly be altered in the future to improve the process. Any process can in theory be improved, and we would support continued review and improvement of the IARC processes. This does not mean, however, that the current procedures are flawed.CONCLUSIONS: The IARC Monographs have made, and continue to make, major contributions to the scientific underpinning for societal actions to improve the public's health.
|
|
| 11. |
- Opheim, G., et al.
(författare)
-
7T Epilepsy Task Force Consensus Recommendations on the Use of 7T MRI in Clinical Practice
- 2021
-
Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 96:7, s. 327-341
-
Tidskriftsartikel (refereegranskat)abstract
- Identifying a structural brain lesion on MRI has important implications in epilepsy and is the most important factor that correlates with seizure freedom after surgery in patients with drug-resistant focal onset epilepsy. However, at conventional magnetic field strengths (1.5 and 3T), only approximately 60%-85% of MRI examinations reveal such lesions. Over the last decade, studies have demonstrated the added value of 7T MRI in patients with and without known epileptogenic lesions from 1.5 and/or 3T. However, translation of 7T MRI to clinical practice is still challenging, particularly in centers new to 7T, and there is a need for practical recommendations on targeted use of 7T MRI in the clinical management of patients with epilepsy. The 7T Epilepsy Task Force-an international group representing 21 7T MRI centers with experience from scanning over 2,000 patients with epilepsy-would hereby like to share its experience with the neurology community regarding the appropriate clinical indications, patient selection and preparation, acquisition protocols and setup, technical challenges, and radiologic guidelines for 7T MRI in patients with epilepsy. This article mainly addresses structural imaging; in addition, it presents multiple nonstructural MRI techniques that benefit from 7T and hold promise as future directions in epilepsy. Answering to the increased availability of 7T MRI as an approved tool for diagnostic purposes, this article aims to provide guidance on clinical 7T MRI epilepsy management by giving recommendations on referral, suitable 7T MRI protocols, and image interpretation.
|
|
| 12. |
|
|
| 13. |
- Hertz, E., et al.
(författare)
-
First Clinicogenetic Description of Parkinson's Disease Related to GBA Mutation S107L
- 2019
-
Ingår i: Movement Disorders Clinical Practice. - : Wiley. - 2330-1619. ; 6:3, s. 254-258
-
Tidskriftsartikel (refereegranskat)abstract
- Background Mutations in the glucocerebrosidase gene (GBA) are a common genetic risk factor for Parkinson's disease (PD). Mutations in the N-terminus part of GBA are less commonly found in association with PD than those in the C-terminus. Phenotypic characterization of GBA-related PD has been challenging, in part attributed to differential impact of distinct GBA mutations. Aim To provide a phenotypic description of two patients with PD heterozygous for the GBA mutation S107L. The S107L mutation is located in the catalytic domain of glucocerebrosidase and has not previously been reported in patients with PD. Methods Motor and nonmotor symptoms (NMS) of PD were evaluated using established rating scales and questionnaires. The genotype was determined by Sanger sequencing. Results Two half-brothers, both heterozygous carriers of S107L, exhibited an early PD onset with several NMS. Conclusions In these patients, heterozygosity for S107L was associated with an early onset of PD with NMS.
|
|
| 14. |
|
|
| 15. |
- Karadima, G, et al.
(författare)
-
Nondisjunction studies in trisomy 8.
- 1997
-
Ingår i: CYTOGENETICS AND CELL GENETICS. - 0301-0171. ; 77:1-2, s. P105-P105
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
- Markaki, I., et al.
(författare)
-
Cerebrospinal Fluid Levels of Kininogen-1 Indicate Early Cognitive Impairment in Parkinson’s Disease
- 2020
-
Ingår i: Movement Disorders. - : John Wiley & Sons. - 0885-3185 .- 1531-8257.
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Cognitive impairment is common in patients with PD. Core markers of Alzheimer’s dementia have been related also to PD dementia, but no disease-specific signature to predict PD dementia exists to date. Objectives: The aim of this study was to investigate CSF markers associated with cognition in early PD. Methods: A high-throughput suspension bead array examined 216 proteins in CSF of 74 PD patients in the AETIONOMY project. Cognitive function was assessed with Repeatable Battery for the Assessment of the Neuropsychological Status, Montreal Cognitive Assessment, and Mini-Mental State Examination. Results: Of 69 patients with complete data, 34 had high (≥90) and 35 had low Repeatable Battery for the Assessment of the Neuropsychological Status total score (<90). Of 14 proteins in CSF that differed in levels between groups, increased kininogen-1, validated with several antibodies, was independently associated with lower Repeatable Battery for the Assessment of the Neuropsychological Status and Montreal Cognitive Assessment scores after adjustment for confounders. Conclusions: Kininogen-1 levels in CSF may serve as a marker of cognitive impairment in PD.
|
|
| 20. |
|
|
| 21. |
- Bertilson, Michael, et al.
(författare)
-
Laboratory soft-x-ray microscope for cryotomography of biological specimens
- 2011
-
Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 36:14, s. 2728-2730
-
Tidskriftsartikel (refereegranskat)abstract
- Soft-x-ray cryotomography allows quantitative and high-resolution three-dimensional imaging of intact unstained cells. To date, the method relies on synchrotron-radiation sources, which limits accessibility for researchers. Here we present a laboratory water-window microscope for cryotomography. It is based on a lambda = 2.48nm liquid-jet laser-plasma source, a normal-incidence multilayer condenser, a 30nm zone-plate objective, and a cryotilt sample holder. We demonstrate high-resolution imaging, as well as quantitative tomographic imaging, of frozen intact cells. The reconstructed tomogram of the intracellular local absorption coefficient shows details down to similar to 100nm.
|
|
| 22. |
- Blokzijl, Andries, et al.
(författare)
-
Protein biomarker validation via proximity ligation assays
- 2014
-
Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1844:5, s. 933-939
-
Forskningsöversikt (refereegranskat)abstract
- The ability to detect minute amounts of specific proteins or protein modifications in blood as biomarkers for a plethora of human pathological conditions holds great promise for future medicine. Despite a large number of plausible candidate protein biomarkers published annually, the translation to clinical use is impeded by factors such as the required size of the initial studies, and limitations of the technologies used. The proximity ligation assay (PLA) is a versatile molecular tool that has the potential to address some obstacles, both in validation of biomarkers previously discovered using other techniques, and for future routine clinical diagnostic needs. The enhanced specificity of PIA extends the opportunities for large-scale, high-performance analyses of proteins. Besides advantages in the form of minimal sample consumption and an extended dynamic range, the PLA technique allows flexible assay reconfiguration. The technology can be adapted for detecting protein complexes, proximity between proteins in extracellular vesicles or in circulating tumor cells, and to address multiple post-translational modifications in the same protein molecule. We discuss herein requirements for biomarker validation, and how PLA may play an increasing role in this regard. We describe some recent developments of the technology, including proximity extension assays, the use of recombinant affinity reagents suitable for use in proximity assays, and the potential for single cell proteomics. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge. (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 23. |
|
|
| 24. |
|
|
| 25. |
- Eriksson, Fredrik, et al.
(författare)
-
14.5% near-normal incidence reflectance of Cr/Sc x-ray multilayer mirrors for the water window
- 2003
-
Ingår i: Optics Letters. - 0146-9592 .- 1539-4794. ; 28:24, s. 2494-2496
-
Tidskriftsartikel (refereegranskat)abstract
- Cr/Sc multilayer mirrors, synthesized by ion-assisted magnetron sputter deposition, are proved to have a high near-normal reflectivity of R = 14.5% at a grazing angle of 87.5degrees measured at the wavelength A = 3.11 nm, which is an improvement of more than 31% compared with previously published results. Elastic recoil detection analyses show that the mirrors contained as much as 15 at. % of N and traces of C and O. Soft x-ray reflectivity simulations reveal interface widths of sigma = 0.34 nm and an exceptionally small layer thickness drift of similar to1.6 X 10(-5) nm/multilayer period throughout the stack. Simulations show that a reflectivity of R = 25.6% is attainable if impurities and layer thickness drift can be eliminated. The abrupt interfaces are achieved with ion assistance with a low ion energy of 24 eV and high ion-to-metal flux ratios of 7.1 and 23.1 during Cr and Se sputter deposition, respectively. In addition, a near-normal incidence reflectivity of 5.5% for the C VI emission line (lambda = 3.374 nm) from a laser plasma source was verified.
|
|
| 26. |
- Field, Dawn, et al.
(författare)
-
The minimum information about a genome sequence (MIGS) specification.
- 2008
-
Ingår i: Nature biotechnology. - : Springer Science and Business Media LLC. - 1546-1696 .- 1087-0156. ; 26:5, s. 541-7
-
Tidskriftsartikel (refereegranskat)abstract
- With the quantity of genomic data increasing at an exponential rate, it is imperative that these data be captured electronically, in a standard format. Standardization activities must proceed within the auspices of open-access and international working bodies. To tackle the issues surrounding the development of better descriptions of genomic investigations, we have formed the Genomic Standards Consortium (GSC). Here, we introduce the minimum information about a genome sequence (MIGS) specification with the intent of promoting participation in its development and discussing the resources that will be required to develop improved mechanisms of metadata capture and exchange. As part of its wider goals, the GSC also supports improving the 'transparency' of the information contained in existing genomic databases.
|
|
| 27. |
- Fogelqvist, Emelie, et al.
(författare)
-
The Stockholm laboratory cryo x-ray microscope : towards cell-cell interaction studies
- 2013
-
Ingår i: 11th International Conference On X-Ray Microscopy (XRM2012). - : Institute of Physics (IOP). ; , s. 012054-
-
Konferensbidrag (refereegranskat)abstract
- We describe recent improvements in the Stockholm laboratory x-ray microscope and the first experiments aiming towards studies of cell-cell interaction. The shorter exposure time due to a higher brightness laser-plasma source will become of large importance for tomography while the reproducible cryo preparation of few-cell samples is essential for the interaction studies.
|
|
| 28. |
- Hansson, B. A. M., et al.
(författare)
-
Characterisation of a liquid-xenon jet laser-plasma extreme-ultraviolet source
- 2004
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 75:6, s. 2122-2129
-
Tidskriftsartikel (refereegranskat)abstract
- A liquid-xenon-jet laser-plasma source for extreme-ultraviolet (EUV) and soft-x-ray generation has been characterized. Being a source candidate for EUV lithography (EUVL), we especially focus on parameters important for the integration of the source in EUVL systems. The deep-ultraviolet (DUV) out-of-band radiation (=120–400 nm) was quantified, to within a factor of two, using a flying-circus tool together with a transmission-grating spectrograph resulting in a total DUV conversion efficiency (CE) of ~0.33%/2sr. The size and the shape of the xenon plasma was investigated using an in-band-only EUV microscope, based on a spherical Mo/Si multilayer mirror and a charge-coupled device detector. Scalability of the source size from 20–270 µm full width at half maximum was shown. The maximum repetition-rate sustainable by the liquid-xenon-jet target was simulated by a double-pulse experiment indicating feasibility of >17 kHz operation. The xenon-ion energy distribution from the plasma was determined in a time-of-flight experiment with a Faraday-cup detector showing the presence of multi-kilo-electron-volt ions. Sputtering of silicon witness plates exposed to the plasma was observed, while a xenon background of >1 mbar was shown to eliminate the sputtering. It is concluded that the source has potential to meet the requirements of future EUVL systems.
|
|
| 29. |
- Hertz, E, et al.
(författare)
-
GM1 Is Cytoprotective in GPR37-Expressing Cells and Downregulates Signaling
- 2021
-
Ingår i: International journal of molecular sciences. - : MDPI AG. - 1422-0067. ; 22:23
-
Tidskriftsartikel (refereegranskat)abstract
- G-protein-coupled receptors (GPCRs) are commonly pharmacologically modulated due to their ability to translate extracellular events to intracellular changes. Previously, studies have mostly focused on protein–protein interactions, but the focus has now expanded also to protein–lipid connections. GM1, a brain-expressed ganglioside known for neuroprotective effects, and GPR37, an orphan GPCR often reported as a potential drug target for diseases in the central nervous system, have been shown to form a complex. In this study, we looked into the functional effects. Endogenous GM1 was downregulated when stably overexpressing GPR37 in N2a cells (N2aGPR37-eGFP). However, exogenous GM1 specifically rescued N2aGPR37-eGFP from toxicity induced by the neurotoxin MPP+. The treatment did not alter transcription levels of GPR37 or the enzyme responsible for GM1 production, both potential mechanisms for the effect. However, GM1 treatment inhibited cAMP-dependent signaling from GPR37, here reported as potentially consecutively active, possibly contributing to the protective effects. We propose an interplay between GPR37 and GM1 as one of the many cytoprotective effects reported for GM1.
|
|
| 30. |
|
|
| 31. |
- Hoppe, R., et al.
(författare)
-
Full characterization of a focused wavefield with sub 100 nm resolution
- 2013
-
Ingår i: Advances In X-Ray Free-Electron Lasers II. - : SPIE - International Society for Optical Engineering. - 9780819495808 ; , s. 87780G-
-
Konferensbidrag (refereegranskat)abstract
- A hard x-ray free-electron laser (XFEL) provides an x-ray source with an extraordinary high peak-brilliance, a time structure with extremely short pulses and with a large degree of coherence, opening the door to new scientific fields. Many XFEL experiments require the x-ray beam to be focused to nanometer dimensions or, at least, benefit from such a focused beam. A detailed knowledge about the illuminating beam helps to interpret the measurements or is even inevitable to make full use of the focused beam. In this paper we report on focusing an XFEL beam to a transverse size of 125nm and how we applied ptychographic imaging to measure the complex wavefield in the focal plane in terms of phase and amplitude. Propagating the wavefield back and forth we are able to reconstruct the full caustic of the beam, revealing aberrations of the nano-focusing optic. By this method we not only obtain the averaged illumination but also the wavefield of individual XFEL pulses.
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
|
|
| 35. |
- McGrath, Patrick J., et al.
(författare)
-
Core outcome domains and measures for pediatric acute and chronic/recurrent pain clinical trials : PedIMMPACT recommendations
- 2008
-
Ingår i: Journal of Pain. - : Elsevier BV. - 1526-5900 .- 1528-8447. ; 9:9, s. 771-83
-
Tidskriftsartikel (refereegranskat)abstract
- Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 26 professionals from academia, governmental agencies, and the pharmaceutical industry participated in a 2-stage Delphi poll and a consensus meeting that identified core outcome domains and measures that should be considered in clinical trials of treatments for acute and chronic pain in children and adolescents. Consensus was refined by consultation with the international pediatric pain community through announcement of our recommendations on the Pediatric Pain List and inviting and incorporating comments from external sources. There was consensus that investigators conducting pediatric acute pain clinical trials should consider assessing outcomes in pain intensity; global judgment of satisfaction with treatment; symptoms and adverse events; physical recovery; emotional response; and economic factors. There was also agreement that investigators conducting pediatric clinical trials in chronic and recurrent pain should consider assessing outcomes in pain intensity; physical functioning; emotional functioning; role functioning; symptoms and adverse events; global judgment of satisfaction with treatment; sleep; and economic factors. Specific measures or measurement strategies were recommended for different age groups for each domain. PERSPECTIVE: Based on systematic review and consensus of experts, core domains and measures for clinical trials to treat pain in children and adolescents were defined. This will assist in comparison and pooling of data and promote evidence-based treatment, encourage complete reporting of outcomes, simplify the review of proposals and manuscripts, and facilitate clinicians making informed decisions regarding treatment.
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
- Seiboth, F., et al.
(författare)
-
Focusing XFEL SASE pulses by rotationally parabolic refractive x-ray lenses
- 2014
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 499:1, s. 012004-
-
Tidskriftsartikel (refereegranskat)abstract
- Using rotationally parabolic refractive x-ray lenses made of beryllium, we focus hard x-ray free-electron laser pulses of the Linac Coherent Light Source (LCLS) down to a spot size in the 100 nm range. We demonstrated efficient nanofocusing and characterized the nanofocused wave field by ptychographic imaging [A. Schropp, et al., Sci. Rep. 3, 1633 (2013)] in the case of monochromatic LCLS pulses produced by a crystal monochromator that decreases the LCLS bandwidth down to ΔE/E 1.4 · 10-4. The full spectrum of LCLS pulses generated by self-amplified spontaneous emission (SASE), however, fluctuates and has a typical bandwidth of a few per mille (ΔE/E 2 · 10-3). Due to the dispersion in the lens material, a polychromatic nanobeam generated by refractive x-ray lenses is affected by chromatic aberration. After reviewing the chromaticity of refractive x-ray lenses, we discuss the influence of increased bandwidth on the quality of a nanofocused SASE pulse.
|
|
| 39. |
|
|
| 40. |
- Twengström, William, et al.
(författare)
-
Can laboratory x-ray virtual histology provide intraoperative 3D tumor resection margin assessment?
- 2021
-
Ingår i: DEVELOPMENTS IN X-RAY TOMOGRAPHY XIII. - : SPIE-Intl Soc Optical Eng.
-
Konferensbidrag (refereegranskat)abstract
- Surgery is an essential part of the curative plan for most patients affected with solid tumors. The outcome of such surgery, e.g., recurrence rates and ultimately patient survival, depends on several factors where the resection margin is of key importance. Presently the resection margin is assessed by classical histology, which is time-consuming (several days), destructive, and basically only gives two-dimensional information. Clearly it would be advantageous if immediate feedback on tumor extension in all three dimensions were available to the surgeon intra-operatively. In the present paper we investigate a laboratory propagation-based phase-contrast x-ray computed tomography (CT) system that provides the resolution, contrast, and, potentially, the speed for this purpose. The system relies on a liquid-metal jet micro-focus source and a scintillator-coated CMOS detector. The study is performed on paraffin-embedded non-stained samples of human pancreatic neuroendocrine tumors, liver intrahepatic cholangiocarcinoma, and pancreatic serous cystic neoplasm (benign). We observe tumors with distinct and sharp edges having cellular resolution (similar to 10 mu m) as well as many assisting histological landmarks, allowing for resection margin assessment. All x-ray data is compared with classical histology. The agreement is excellent, and we conclude that the method has potential for intra-operative three-dimensional virtual histology.
|
|
| 41. |
- Uhlén, Fredrik, et al.
(författare)
-
Damage investigation on tungsten and diamond diffractive optics at a hard x-ray free-electron laser
- 2013
-
Ingår i: Optics Express. - : Optical Society America. - 1094-4087. ; 21:7, s. 8051-8061
-
Tidskriftsartikel (refereegranskat)abstract
- Focusing hard x-ray free-electron laser radiation with extremely high fluence sets stringent demands on the x-ray optics. Any material placed in an intense x-ray beam is at risk of being damaged. Therefore, it is crucial to find the damage thresholds for focusing optics. In this paper we report experimental results of exposing tungsten and diamond diffractive optics to a prefocused 8.2 keV free-electron laser beam in order to find damage threshold fluence levels. Tungsten nanostructures were damaged at fluence levels above 500 mJ/cm(2). The damage was of mechanical character, caused by thermal stress variations. Diamond nanostructures were affected at a fluence of 59 000 mJ/cm(2). For fluence levels above this, a significant graphitization process was initiated. Scanning Electron Microscopy (SEM) and mu-Raman analysis were used to analyze exposed nanostructures.
|
|
| 42. |
|
|
| 43. |
|
|
| 44. |
|
|
| 45. |
|
|
