| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Camilo, F., et al.
(författare)
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Revival of the Magnetar PSR J1622-4950: Observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
- 2018
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 856:2
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Tidskriftsartikel (refereegranskat)abstract
- New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least early 2015, reactivated between 2017 March 19 and April 5. The radio flux density, while variable, is approximately 100 larger than during its dormant state. The X-ray flux one month after reactivation was at least 800 larger than during quiescence, and has been decaying exponentially on a 111 19 day timescale. This high-flux state, together with a radio-derived rotational ephemeris, enabled for the first time the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV pulsed fraction is comparable to the smallest observed for magnetars. The overall pulsar geometry inferred from polarized radio emission appears to be broadly consistent with that determined 6-8 years earlier. However, rotating vector model fits suggest that we are now seeing radio emission from a different location in the magnetosphere than previously. This indicates a novel way in which radio emission from magnetars can differ from that of ordinary pulsars. The torque on the neutron star is varying rapidly and unsteadily, as is common for magnetars following outburst, having changed by a factor of 7 within six months of reactivation.
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| 3. |
- Ferraro, Gino B., et al.
(författare)
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Fatty acid synthesis is required for breast cancer brain metastasis
- 2021
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Ingår i: Nature Cancer. - : Springer Science and Business Media LLC. - 2662-1347. ; 2:4, s. 414-428
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Tidskriftsartikel (refereegranskat)abstract
- Brain metastases are refractory to therapies that control systemic disease in patients with human epidermal growth factor receptor 2-positive breast cancer and the brain microenvironment contributes to this therapy resistance. Nutrient availability can vary across tissues, therefore metabolic adaptations required for brain metastatic breast cancer growth may introduce liabilities that can be exploited for therapy. Here we assessed how metabolism differs between breast tumors in brain versus extracranial sites and found that fatty acid synthesis is elevated in breast tumors growing in the brain. We determine that this phenotype is an adaptation to decreased lipid availability in the brain relative to other tissues, resulting in site-specific dependency on fatty acid synthesis for breast tumors growing at this site. Genetic or pharmacological inhibition of fatty acid synthase reduces human epidermal growth factor receptor 2-positive breast tumor growth in the brain, demonstrating that differences in nutrient availability across metastatic sites can result in targetable metabolic dependencies.
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| 4. |
- Karlsson, R., et al.
(författare)
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Proteotyping: Proteomic characterization, classification and identification of microorganisms - A prospectus
- 2015
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Ingår i: Systematic and Applied Microbiology. - : Elsevier BV. - 0723-2020. ; 38:4, s. 246-257
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Forskningsöversikt (refereegranskat)abstract
- Modern microbial systematics requires a range of methodologies for the comprehensive characterization, classification and identification of microorganisms. While whole-genome sequences provide the ultimate reference for defining microbial phylogeny and taxonomy, selected biomarker-based strategies continue to provide the means for the bulk of microbial systematic studies. Proteomics, the study of the expression of genes, as well as the structure and function of the resulting proteins, offers indirect measures of genome sequence data. Recent developments in applications of proteomics for analyzing microorganisms have paralleled the growing microbial genome sequence database, as well as the evolution of mass spectrometry (MS) instrumentation and bioinformatics. MALDI-TOF MS, which generates proteomic mass patterns for 'fingerprint'-based characterizations, has provided a marked breakthrough for microbial identification. However, MALDI-TOF MS is limited in the number of targets that can be detected for strain characterization. Advanced methods of tandem mass spectrometry, in which proteins and peptides generated from proteins, are characterized and identified, using LC-MS/MS, provide the ability to detect hundreds or thousands of expressed microbial strain markers for high-resolution characterizations and identifications. Model studies demonstrate the application of proteomics-based analyses for bacterial species- and strain-level detection and identification and for characterization of environmentally relevant, metabolically diverse bacteria. Proteomics-based approaches represent an emerging complement to traditional methods of characterizing microorganisms, enabling the elucidation of the expressed biomarkers of genome sequence information, which can be applied to 'proteotyping' applications of microorganisms at all taxonomic levels. (C) 2015 Elsevier GmbH. All rights reserved.
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| 5. |
- Lau, Allison N., et al.
(författare)
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Dissecting cell-type-specific metabolism in pancreatic ductal adenocarcinoma
- 2020
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Ingår i: eLife. - 2050-084X. ; 9, s. 1-35
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Tidskriftsartikel (refereegranskat)abstract
- Tumors are composed of many different cell types including cancer cells, fibroblasts, and immune cells. Dissecting functional metabolic differences between cell types within a mixed population can be challenging due to the rapid turnover of metabolites relative to the time needed to isolate cells. To overcome this challenge, we traced isotope-labeled nutrients into macromolecules that turn over more slowly than metabolites. This approach was used to assess differences between cancer cell and fibroblast metabolism in murine pancreatic cancer organoid-fibroblast co-cultures and tumors. Pancreatic cancer cells exhibited increased pyruvate carboxylation relative to fibroblasts, and this flux depended on both pyruvate carboxylase and malic enzyme 1 activity. Consequently, expression of both enzymes in cancer cells was necessary for organoid and tumor growth, demonstrating that dissecting the metabolism of specific cell populations within heterogeneous systems can identify dependencies that may not be evident from studying isolated cells in culture or bulk tissue.
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| 6. |
- Ludick, D. J., et al.
(författare)
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A comparison of domain decomposition techniques for analysing disjoint finite antenna arrays
- 2014
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Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 2164-3342. - 9788890701849 ; , s. 2411-2415
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Konferensbidrag (refereegranskat)abstract
- The purpose of this work is to present a quantitative comparison between three Method-of-Moments based domain decomposition techniques that are used for the analysis of large, disjoint finite antenna arrays. The methods considered are the Characteristic Basis Function Method, the Domain Green's Function Method, and a newly proposed improved version of the DGFM, i.e., the i-DGFM. The computational complexities of the techniques are compared in terms of runtime and memory usage. Both active and passive antenna arrays are considered.
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| 7. |
- Ludick, D. J., et al.
(författare)
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Applying the CBFM-enhanced domain Green's function method to the analysis of large disjoint subarray antennas
- 2013
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Ingår i: Proceedings of the 2013 International Conference on Electromagnetics in Advanced Applications, ICEAA 2013. - 9781467357074 ; , s. 94-97
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Konferensbidrag (refereegranskat)abstract
- This paper considers the efficient numerical analysis of large, finite antenna arrays comprising of disjoint subarrays by using the Domain Green's Function Method (DGFM) [1] in conjunction with the Characteristic Basis Function Method (CBFM) [2]. In the CBFM-enhanced DGFM we consider large arrays consisting of multiple disjoint subarrays and impose the infinite array type assumption, i.e. that the currents on subarrays are identical except for a complex-valued scaling factor. Scan impedance matrices are then constructed for each of the subarrays from the block-partitioned CBFM reduced impedance matrix which account for the mutual coupling in the array environment. Runtime and memory usage scale efficiently for the CBFM-enhanced DGFM as we limit the computational complexity to that required to analyse a single subarray. The paper discusses the hybridisation of the DGFM with the CBFM, and illustrates the results of applying the proposed solution technique to an example consisting of a large finite array of disjoint subarrays. © 2013 IEEE.
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| 8. |
- Ludick, D. J., et al.
(författare)
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Efficient Analysis of Large Aperiodic Antenna Arrays Using the Domain Green's Function Method
- 2014
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Ingår i: IEEE Transactions on Antennas and Propagation. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-926X .- 1558-2221. ; 62:4, s. 1579-1588
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Tidskriftsartikel (refereegranskat)abstract
- An efficient method-of-moments (MoM) based domain decomposition technique, viz., the domain Green's function method (DGFM), is presented for analyzing large antenna arrays. The DGFM is a perturbation technique where mutual coupling between array elements is accounted for during the formulation of an active impedance matrix for each domain/array element. The active current distribution on the entire array geometry is obtained by solving the smaller matrix equations related to the elements, and not that of the problem as a whole. This leads to a significant saving in both runtime and memory usage. The method also takes into account the edge effects attributed to the finite size of the array, complex excitations with nonlinear phase shift and is not limited to periodic array configurations. The DGFM is an approximation and assumes a slowly varying current distribution between domains. A novel way to mitigate the aforementioned, by including secondary coupling effects, is also discussed. Furthermore, an efficient active impedance matrix fill strategy is presented where the active impedance matrix summation is truncated to include only a certain number of terms. Parallelization using both distributed and shared memory programming models have also been applied to the DGFM, to further optimize runtime and memory usage.
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| 9. |
- Yu, Liyang, 1986, et al.
(författare)
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Isothermal Crystallization Kinetics and Time-Temperature-Transformation of the Conjugated Polymer: Poly(3-(2 '-ethyl)hexylthiophene)
- 2017
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 1520-5002 .- 0897-4756. ; 29:13, s. 5654-5662
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Tidskriftsartikel (refereegranskat)abstract
- Thermal annealing strongly impacts the nano- and microstructure of conjugated polymers. Despite the fundamental importance for the resulting optoelectronic behavior of this class of materials, the underlying crystallization processes have not received the same attention that is encountered in other disciplines of materials science. The question arises whether classical treatment of nucleation and growth phenomena is truly applicable to conjugated polymers? Here, the isothermal crystallization behavior of the conjugated polymer poly(3-(2'-ethyl)hexylthiophene) (P3EHT) is monitored with differential scanning calorimetry (DSC). Avrami analysis reveals growth- and nucleation limited temperature regimes that are separated by the maximum rate of crystallization. The molecular weight of the polymer is found to strongly influence the absolute rate of crystallization at the same degree of undercooling relative to the melting temperature. A combination of optical microscopy and grazing-incidence wide-angle X-ray scattering (GIWAXS) confirm's that the resulting nano- and microstructure strongly correlate with the selected isothermal annealing temperature. Hence, this work establishes that classical nucleation and growth theory can be applied to describe the solidification behavior of the semicrystalline conjugated polymer P3EHT.
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| 10. |
- Zhou, Beckett Yx, et al.
(författare)
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Adjoint-based Broadband Noise Minimization using Stochastic Noise Generation
- 2019
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Ingår i: 25th AIAA/CEAS Aeroacoustics Conference. - Reston, Virginia : American Institute of Aeronautics and Astronautics. - 9781624105883
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present an adjoint-based broadband noise minimization framework using stochastic noise generation (SNG). The SNG module is implemented in the open-source multi-physics solver suite SU2 and coupled with the existing Reynolds-averaged Navier-Stokes (RANS) to allow fast assessment of broadband noise sources. In addition, a discrete adjoint solver on the basis of algorithmic differentiation (AD) is developed for the coupled RANS-SNG system to enable efficient evaluation of broadband noise design sensitivities. The adjoint-based RANS-SNG framework developed in this work not only avoids the regularization problem that plagues the adjoint solutions for scale-resolving simulations, but also significantly lowers the computational cost and leads to a faster turn-around time for the initial design evaluation phase. Current results show that the RANS-SNG method can efficiently provide broadband noise level assessment for various configurations without resorting to computationally prohibitive scale-resolving simulations. Furthermore, current results also show that the design sensitivities computed by the AD-based coupled adjoint-RANS-SNG solver is highly accurate. Finally, shape optimizations performed on the basis of such coupled-sensitivity are shown to be effective in removing the broadband noise source near the trailing edge of a NACA0012 airfoil profile as well as around the side-edge of an isolated flap.
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