| 51. |
- Kjær, Kasper S., et al.
(författare)
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Ligand manipulation of charge transfer excited state relaxation and spin crossover in [Fe(2,2'-bipyridine)2(CN)2]
- 2017
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Ingår i: Structural Dynamics. - : AIP Publishing. - 2329-7778. ; 4:4
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Tidskriftsartikel (refereegranskat)abstract
- We have used femtosecond resolution UV-visible and Kβ x-ray emission spectroscopy to characterize the electronic excited state dynamics of [Fe(bpy)2(CN)2], where bpy=2,20-bipyridine, initiated by metal-to-ligand charge transfer (MLCT) excitation. The excited-state absorption in the transient UV-visible spectra, associated with the 2,20-bipyridine radical anion, provides a robust marker for the MLCT excited state, while the transient Kβ x-ray emission spectra provide a clear measure of intermediate and high spin metal-centered excited states. From these measurements, we conclude that the MLCT state of [Fe(bpy)2(CN)2] undergoes ultrafast spin crossover to a metalcentered quintet excited state through a short lived metal-centered triplet transient species. These measurements of [Fe(bpy)2(CN)2] complement prior measurement performed on [Fe(bpy)3]2+ and [Fe(bpy)(CN)4]2- in dimethylsulfoxide solution and help complete the chemical series [Fe(bpy)N(CN)6-2N]2N-4, whereN=1-3. The measurements confirm that simple ligand modifications can significantly change the relaxation pathways and excited state lifetimes and support the further investigation of light harvesting and photocatalytic applications of 3d transition metal complexes.
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| 52. |
- Kjaer, Per, et al.
(författare)
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GLA:D-(R) Back group-based patient education integrated with exercises to support self-management of back pain- development, theories and scientific evidence-
- 2018
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Ingår i: BMC Musculoskeletal Disorders. - : BMC. - 1471-2474. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundClinical guidelines recommend that people with back pain be given information and education about their back pain, advice to remain active and at work, and exercises to improve mobility and physical activity. Guidelines, however, rarely describe how this is best delivered. The aim of this paper is to present the development, theories, and underlying evidence for GLA:D Back - a group education and exercise program that translates guideline recommendations into a clinician-delivered program for the promotion of self-management in people with persistent/recurrent back pain.MethodsGLA:D Back, which included a rationale and objectives for the program, theory and evidence for the interventions, and program materials, was developed using an iterative process. The content of patient education and exercise programs tested in randomised trials was extracted and a multidisciplinary team of expert researchers and clinicians prioritised common elements hypothesised to improve back pain beliefs and management skills. The program was tested on eight people with persistent back pain in a university clinic and 152 patients from nine primary care physiotherapy and chiropractic clinics. Following feedback from the clinicians and patients involved, the working version of the program was created.ResultsEducational components included pain mechanisms, pain modulation, active coping strategies, imaging, physical activity, and exercise that emphasised a balance between the sum of demands and the individuals capacity. These were operationalised in PowerPoint presentations with supporting text to aid clinicians in delivering two one-hour patient education lectures.The exercise program included 16 supervised one-hour sessions over 8weeks, each comprising a warm-up section and eight types of exercises for general flexibility and strengthening of six different muscle groups at four levels of difficulty. The aims of the exercises were to improve overall back fitness and, at the same time, encourage patients to explore variations in movement by incorporating education content into the exercise sessions.ConclusionFrom current best evidence about prognostic factors in back pain and effective treatments for back pain, research and clinical experts developed a ready-to-use structured program - GLA:D (R) Back - to support self-management for people with persistent/recurrent back pain.
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| 53. |
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| 54. |
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| 55. |
- Leshchev, Denis, et al.
(författare)
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Tracking the picosecond deactivation dynamics of a photoexcited iron carbene complex by time-resolved X-ray scattering
- 2018
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 9:2, s. 405-414
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Tidskriftsartikel (refereegranskat)abstract
- Recent years have seen the development of new iron-centered N-heterocyclic carbene (NHC) complexes for solar energy applications. Compared to typical ligand systems, the NHC ligands provide Fe complexes with longer-lived metal-to-ligand charge transfer (MLCT) states. This increased lifetime is ascribed to strong ligand field splitting provided by the NHC ligands that raises the energy levels of the metal centered (MC) states and therefore reduces the deactivation efficiency of MLCT states. Among currently known NHC systems, [Fe(btbip)2]2+ (btbip = 2,6-bis(3-tert-butyl-imidazol-1-ylidene)pyridine) is a unique complex as it exhibits a short-lived MC state with a lifetime on the scale of a few hundreds of picoseconds. Hence, this complex allows for a detailed investigation, using 100 ps X-ray pulses from a synchrotron, of strong ligand field effects on the intermediate MC state in an NHC complex. Here, we use time-resolved wide angle X-ray scattering (TRWAXS) aided by density functional theory (DFT) to investigate the molecular structure, energetics and lifetime of the high-energy MC state in the Fe-NHC complex [Fe(btbip)2]2+ after excitation to the MLCT manifold. We identify it as a 260 ps metal-centered quintet (5MC) state, and we refine the molecular structure of the excited-state complex verifying the DFT results. Using information about the hydrodynamic state of the solvent, we also determine, for the first time, the energy of the 5MC state as 0.75 ± 0.15 eV. Our results demonstrate that due to the increased ligand field strength caused by NHC ligands, upon transition from the ground state to the 5MC state, the metal to ligand bonds extend by unusually large values: by 0.29 Å in the axial and 0.21 Å in the equatorial direction. These results imply that the transition in the photochemical properties from typical Fe complexes to novel NHC compounds is manifested not only in the destabilization of the MC states, but also in structural distortion of these states.
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| 56. |
- Sundin, Anders, 1954-, et al.
(författare)
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ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumors : Radiological, Nuclear Medicine & Hybrid Imaging.
- 2017
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Ingår i: Neuroendocrinology. - : S. Karger AG. - 0028-3835 .- 1423-0194. ; 105:3, s. 212-244
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Tidskriftsartikel (refereegranskat)abstract
- Contrast-enhanced computed tomography (CT) of the neckthorax-abdomen and pelvis, including 3-phase examination of the liver, constitutes the basic imaging for primary neuroendocrine tumor (NET) diagnosis, staging, surveillance, and therapy monitoring. CT characterization of lymph nodes is difficult because of inadequate size criteria (short axis diameter), and bone metastases are often missed. Contrast-enhanced magnetic resonance imaging (MRI) including diffusion-weighted imaging is preferred for the examination of the liver, pancreas, brain and bone. MRI may miss small lung metastases. MRI is less well suited than CT for the examination of extended body areas because of the longer examination procedure. Ultrasonography (US) frequently provides the initial diagnosis of liver metastases and contrast-enhanced US is excellent to characterize liver lesions that remain equivocal on CT/MRI. US is the method of choice to guide the biopsy needle for the histopathological NET diagnosis. US cannot visualize thoracic NET lesions for which CTguided biopsy therefore is used. Endocopic US is the most sensitive method to diagnose pancreatic NETs, and additionally allows for biopsy. Intraoperative US facilitates lesion detection in the pancreas and liver. Somatostatin receptor imaging should be a part of the tumor staging, preoperative imaging and restaging, for which 68 Ga-DOTA-somatostatin analog PET/CT is recommended, which is vastly superior to somatostatin receptor scintigraphy, and facilitates the diagnosis of most types of NET lesions, for example lymph node metastases, bone metastases, liver metastases, peritoneal lesions, and primary small intestinal NETs. (18)FDG-PET/CT is better suited for G3 and high G2 NETs, which generally have higher glucose metabolism and less somatostatin receptor expression than low-grade NETs, and additionally provides prognostic information.
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| 57. |
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| 58. |
- Van Driel, Tim B., et al.
(författare)
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Atomistic characterization of the active-site solvation dynamics of a model photocatalyst
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The interactions between the reactive excited state of molecular photocatalysts and surrounding solvent dictate reaction mechanisms and pathways, but are not readily accessible to conventional optical spectroscopic techniques. Here we report an investigation of the structural and solvation dynamics following excitation of a model photocatalytic molecular system [Ir 2 (dimen) 4 ] 2+, where dimen is para-diisocyanomenthane. The time-dependent structural changes in this model photocatalyst, as well as the changes in the solvation shell structure, have been measured with ultrafast diffuse X-ray scattering and simulated with Born-Oppenheimer Molecular Dynamics. Both methods provide direct access to the solute-solvent pair distribution function, enabling the solvation dynamics around the catalytically active iridium sites to be robustly characterized. Our results provide evidence for the coordination of the iridium atoms by the acetonitrile solvent and demonstrate the viability of using diffuse X-ray scattering at free-electron laser sources for studying the dynamics of photocatalysis.
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| 59. |
- Vanko, Gyoergy, et al.
(författare)
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Detailed Characterization of a Nanosecond-Lived Excited State: X-ray and Theoretical Investigation of the Quintet State in Photoexcited [Fe(terpy)(2)](2+)
- 2015
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 119:11, s. 5888-5902
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Tidskriftsartikel (refereegranskat)abstract
- Theoretical predictions show that depending on the populations of the Fe 3d(xy), 3d(xz), and 3d(yz) orbitals two possible quintet states can exist for the high-spin state of the photoswitchable model system [Fe(terpy)(2)](2+). The differences in the structure and molecular properties of these B-5(2) and E-5 quintets are very small and pose a substantial challenge for experiments to resolve them. Yet for a better understanding of the physics of this system, which can lead to the design of novel molecules with enhanced photoswitching performance, it is vital to determine which high-spin state is reached in the transitions that follow the light excitation. The quintet state can be prepared with a short laser pulse and can be studied with cutting-edge time-resolved X-ray techniques. Here we report on the application of an extended set of X-ray spectroscopy and scattering techniques applied to investigate the quintet state of [Fe(terpy)(2)](2+) 80 ps after light excitation. High-quality X-ray absorption, nonresonant emission, and resonant emission spectra as well as X-ray diffuse scattering data clearly reflect the formation of the high-spin state of the [Fe(terpy)(2)](2+) molecule; moreover, extended X-ray absorption fine structure spectroscopy resolves the Fe-ligand bond-length variations with unprecedented bond-length accuracy in time-resolved experiments. With ab initio calculations we determine why, in contrast to most related systems, one configurational mode is insufficient for the description of the low-spin (LS)-high-spin (HS) transition. We identify the electronic structure origin of the differences between the two possible quintet modes, and finally, we unambiguously identify the formed quintet state as 5E, in agreement with our theoretical expectations.
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| 60. |
- Wang, Yifan, et al.
(författare)
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The BRCA1-Δ11q alternative splice isoform bypasses germline mutations and promotes therapeutic resistance to PARP inhibition and cisplatin
- 2016
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Ingår i: Cancer Research. - 0008-5472. ; 76:9, s. 2778-2790
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Tidskriftsartikel (refereegranskat)abstract
- Breast and ovarian cancer patients harboring BRCA1/2 germline mutations have clinically benefitted from therapy with PARP inhibitor (PARPi) or platinum compounds, but acquired resistance limits clinical impact. In this study, we investigated the impact of mutations on BRCA1 isoform expression and therapeutic response. Cancer cell lines and tumors harboring mutations in exon 11 of BRCA1 express a BRCA1-Δ11q splice variant lacking the majority of exon 11. The introduction of frameshift mutations to exon 11 resulted in nonsense-mediated mRNA decay of full-length, but not the BRCA1-Δ11q isoform. CRISPR/Cas9 gene editing as well as overexpression experiments revealed that the BRCA1-Δ11q protein was capable of promoting partial PARPi and cisplatin resistance relative to full-length BRCA1, both in vitro and in vivo. Furthermore, spliceosome inhibitors reduced BRCA1- Δ11q levels and sensitized cells carrying exon 11 mutations to PARPi treatment. Taken together, our results provided evidence that cancer cells employ a strategy to remove deleterious germline BRCA1 mutations through alternative mRNA splicing, giving rise to isoforms that retain residual activity and contribute to therapeutic resistance.
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