| 1. |
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| 2. |
- Berglund, Lisa, et al.
(författare)
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Glucose-Dependent Insulinotropic Polypeptide (GIP) Stimulates Osteopontin Expression in the Vasculature via Endothelin-1 and CREB.
- 2016
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 65:1, s. 239-254
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Tidskriftsartikel (refereegranskat)abstract
- Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone with extrapancreatic effects beyond glycemic control. Here we demonstrate unexpected effects of GIP signaling in the vasculature. GIP induces the expression of the pro-atherogenic cytokine osteopontin (OPN) in mouse arteries, via local release of endothelin-1 (ET-1) and activation of cAMP response element binding protein (CREB). Infusion of GIP increases plasma OPN levels in healthy individuals. Plasma ET-1 and OPN levels are positively correlated in patients with critical limb ischemia. Fasting GIP levels are higher in individuals with a history of cardiovascular disease (myocardial infarction, stroke) when compared to controls. GIP receptor (GIPR) and OPN mRNA levels are higher in carotid endarterectomies from patients with symptoms (stroke, transient ischemic attacks, amaurosis fugax) than in asymptomatic patients; and expression associates to parameters characteristic of unstable and inflammatory plaques (increased lipid accumulation, macrophage infiltration and reduced smooth muscle cell content). While GIPR expression is predominantly endothelial in healthy arteries from human, mouse, rat and pig; remarkable up-regulation is observed in endothelial and smooth muscle cells upon culture conditions yielding a "vascular disease-like" phenotype. Moreover, a common variant rs10423928 in the GIPR gene associated with increased risk of stroke in type 2 diabetes patients.
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| 3. |
- Fountoulakis, Konstantinos N., et al.
(författare)
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Staging of Schizophrenia With the Use of PANSS : An International Multi-Center Study
- 2019
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Ingår i: International Journal of Neuropsychopharmacology. - : Oxford University Press. - 1461-1457 .- 1469-5111. ; 22:11, s. 681-697
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionA specific clinically relevant staging model for schizophrenia has not yet been developed. The aim of the current study was to evaluate the factor structure of the PANSS and develop such a staging method.MethodsTwenty-nine centers from 25 countries contributed 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Analysis of covariance, Exploratory Factor Analysis, Discriminant Function Analysis, and inspection of resultant plots were performed.ResultsExploratory Factor Analysis returned 5 factors explaining 59% of the variance (positive, negative, excitement/hostility, depression/anxiety, and neurocognition). The staging model included 4 main stages with substages that were predominantly characterized by a single domain of symptoms (stage 1: positive; stages 2a and 2b: excitement/hostility; stage 3a and 3b: depression/anxiety; stage 4a and 4b: neurocognition). There were no differences between sexes. The Discriminant Function Analysis developed an algorithm that correctly classified >85% of patients.DiscussionThis study elaborates a 5-factor solution and a clinical staging method for patients with schizophrenia. It is the largest study to address these issues among patients who are more likely to remain affiliated with mental health services for prolonged periods of time.
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| 4. |
- Gilissen, Herman Kasper, et al.
(författare)
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A framework for evaluating the effectiveness of Flood Emergency Management Systems in Europe
- 2016
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Ingår i: Ecology and Society. - 1708-3087. ; 21:4
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Tidskriftsartikel (refereegranskat)abstract
- Society is faced with a range of contemporary threats to everyday life, from natural and technological hazards to accidents and terrorism. These are embodied within integrated emergency management arrangements that are designed to enhance preparedness and response to such incidents, and in turn facilitate a prompt recovery. Such arrangements must be inherently dynamic and evolve as new threats emerge or as existing threats change. An example of the latter is the changing nature of flooding, which is projected to increase in both frequency and severity with climate change. Recognizing this evolving threat, we focus on the evaluation of the effectiveness of domestic Flood Emergency Management Systems (FEMS) as components of integrated emergency management arrangements. Despite the extensive body of literature that documents success conditions of so-called effective emergency management more broadly, there have been only a few attempts to construct a comprehensive evaluation framework to support objective assessment and cross-country comparison. Addressing this gap, we formulate an evaluation framework specifically tailored to the study of FEMS in Europe, which is then provisionally applied to the study of FEMS in England (UK), France, the Netherlands, Poland, and Sweden. Important differences are observed in how FEMS have evolved in relation to differing contextual backgrounds (political, cultural, administrative, and socio-economic) and exposures to flood hazard. From this provisional assessment, a number of opportunities for, and constraints to, enhancing the effectiveness of FEMS in Europe are discerned. The evaluation framework thus serves as an important stepping stone for further indepth inquiry, and as a valuable tool for future comparative study.
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| 5. |
- Gray, Victor, 1988, et al.
(författare)
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CdS/ZnS core-shell nanocrystal photosensitizers for visible to UV upconversion
- 2017
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6539 .- 2041-6520. ; 8:8, s. 5488-5496
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Tidskriftsartikel (refereegranskat)abstract
- Herein we report the first example of nanocrystal (NC) sensitized triplet-triplet annihilation based photon upconversion from the visible to ultraviolet (vis-to-UV). Many photocatalyzed reactions, such as water splitting, require UV photons in order to function efficiently. Upconversion is one possible means of extending the usable range of photons into the visible. Vis-to-UV upconversion is achieved with CdS/ZnS core-shell NCs as the sensitizer and 2,5-diphenyloxazole (PPO) as annihilator and emitter. The ZnS shell was crucial in order to achieve any appreciable upconversion. From time resolved photoluminescence and transient absorption measurements we conclude that the ZnS shell affects the NC and triplet energy transfer (TET) from NC to PPO in two distinct ways. Upon ZnS growth the surface traps are passivated thus increasing the TET. The shell, however, also acts as a tunneling barrier for TET, reducing the efficiency. This leads to an optimal shell thickness where the upconversion quantum yield (Phi(UC)') is maximized. Here the maximum Phi(UC)' was determined to be 5.2 +/- 0.5% for 4 monolayers of ZnS shell on CdS NCs.
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| 6. |
- Gray, Victor, 1988, et al.
(författare)
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Loss channels in triplet-triplet annihilation photon upconversion: importance of annihilator singlet and triplet surface shapes
- 2017
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 19:17, s. 10931-10939
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Tidskriftsartikel (refereegranskat)abstract
- Triplet-triplet annihilation photon upconversion (TTA-UC) can, through a number of energy transfer processes, efficiently combine two low frequency photons into one photon of higher frequency. TTA-UC systems consist of one absorbing species (the sensitizer) and one emitting species (the annihilator). Herein, we show that the structurally similar annihilators, 9,10-diphenylanthracene (DPA, 1), 9-(4-phenylethynyl)10-phenylanthracene (2) and 9,10-bis(phenylethynyl) anthracene (BPEA, 3) have very different upconversion efficiencies, 15.2 +/- 2.8%, 15.9 +/- 1.3% and 1.6 +/- 0.8%, respectively (of a maximum of 50%). We show that these results can be understood in terms of a loss channel, previously unaccounted for, originating from the difference between the BPEA singlet and triplet surface shapes. The difference between the two surfaces results in a fraction of the triplet state population having geometries not energetically capable of forming the first singlet excited state. This is supported by TD-DFT calculations of the annihilator excited state surfaces as a function of phenyl group rotation. We thereby highlight that the commonly used "spin-statistical factor'' should be used with caution when explaining TTA-efficiencies. Furthermore, we show that the precious metal free zinc octaethylporphyrin (ZnOEP) can be used for efficient sensitization and that the upconversion quantum yield is maximized when sensitizer-annihilator spectral overlap is minimized (ZnOEP with 2).
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| 7. |
- Gray, Victor, 1988, et al.
(författare)
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Photophysical characterization of the 9,10-disubstituted anthracene chromophore and its applications in triplet-triplet annihilation photon upconversion
- 2015
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Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7534 .- 2050-7526. ; 3:42, s. 11111-11121
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Tidskriftsartikel (refereegranskat)abstract
- Molecules based on anthracene are commonly used in applications such as OLEDs and triplet-triplet annihilation upconversion. In future design of blue emitting materials it is useful to know which part of the molecule can be altered in order to obtain new physical properties without losing the inherent optical properties. We have studied the effect of substitution of 9,10-substituted anthracenes. Eight anthracenes with aromatic phenyl and thiophene substituents were synthesised, containing both electron donating and accepting groups. The substitutions were found to affect the UV/Vis absorption only to a small extent, however the fluorescence properties were more affected with the thiophene substituents that decreased the fluorescence quantum yield from unity to
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| 8. |
- Gray, Victor, 1988, et al.
(författare)
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Porphyrin-Anthracene Complexes: Potential in Triplet-Triplet Annihilation Upconversion
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:34, s. 19018-19026
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Tidskriftsartikel (refereegranskat)abstract
- Triplet-triplet annihilation photon upconversion (TTA-UC) systems contain both an absorbing and an emitting molecule, the sensitizer and annihilator, respectively. Through a series of energy-transfer steps, two low frequency,photons can be combined into one high frequency photon. In organic solvents, the required energy transfer steps are limited by diffusion and are relatively efficient. In solid-state systems, however, the diffusion is slower, which usually results in lower efficiencies for these systems. An interesting way around this is to connect the sensitizer and annihilator. In order to increase understanding of the TTA-UC process in supramolecular systems, we synthesized four pyridine-substituted anthracene annihilators capable of coordinating axially to a zinc octaethylporphyrin sensitizer with a maximum binding constant of 6000 M-1 in toluene. This is a first example of a sensitizer-annihilator coordination complex for TTA-UC. Both the upconversion efficiency and the parasitic quenching of excited annihilator singlets by the sensitizer through Forster resonant energy transfer (FRET) were studied. On the basis of the findings herein, possible strategies for future supramolecular TTA systems with minimized FRET quenching are discussed.
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| 9. |
- Gray, Victor, 1988, et al.
(författare)
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Singlet and triplet energy transfer dynamics in self-assembled axial porphyrin-anthracene complexes: Towards supra-molecular structures for photon upconversion
- 2018
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 20:11, s. 7549-7558
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Tidskriftsartikel (refereegranskat)abstract
- Energy and electron transfer reactions are central to many different processes and research fields, from photosynthesis and solar energy harvesting to biological and medical applications. Herein we report a comprehensive study of the singlet and triplet energy transfer dynamics in porphyrin-anthracene coordination complexes. Seven newly synthesized pyridine functionalized anthracene ligands, five with various bridge lengths and two dendrimer structures containing three and seven anthracene units, were prepared. We found that triplet energy transfer from ruthenium octaethylporphyrin to an axially coordinated anthracene is possible, and is in some cases followed by back triplet energy tra nsfer to the porphyrin. The triplet energy transfer follows an exponential distance dependence with an attenuation factor, β, of 0.64 Å -1 . Further, singlet energy transfer from anthracene to the ruthenium porphyrin appears to follow a R 6 Förster distance dependence. Porphyrin-anthracene complexes are also used as triplet sensitizers for triplet-triplet annihilation (TTA) based photon upconversion, demonstrating their potential for photophysical and photochemical applications. The triplet lifetime of the complex is extended by the anthracene ligands, resulting in a threefold increase in the upconversion efficiency, Φ UC to 4.5%, compared to the corresponding ruthenium porphyrin-pyridine complex. Based on the results herein we discuss the future design of supra-molecular structures for TTA upconversion.
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| 10. |
- Gray, Victor, 1988, et al.
(författare)
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Towards efficient solid-state triplet-triplet annihilation based photon upconversion: Supramolecular, macromolecular and self-assembled systems
- 2018
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Ingår i: Coordination Chemistry Reviews. - : Elsevier BV. - 0010-8545. ; 362, s. 54-71
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Forskningsöversikt (refereegranskat)abstract
- Photon upconversion through sensitized Triplet-Triplet Annihilation (TTA-UC) has regained a lot of interest during the last decade mainly due to its potential for significantly increased solar energy harvesting. Other applications such as anti-Stokes fluorescence labels for bio-imaging and drug-targeting have also emerged. Considering practical large scale use of TTA-UC, solid state materials are required. The TTA-UC process depends on a sequence of energy transfer processes and it is a great challenge to maintain high efficiencies while solidifying these diffusion limited energy transfer steps. This review covers the basic, fundamental aspects of TTA-UC, but focuses on the current state of the art of the many attempts to develop solid state based TTA-UC systems. In particular, work aiming at overcoming the diffusion limit though supramolecular, macromolecular or self-assembly approaches are highlighted. (C) 2018 Elsevier B.V. All rights reserved.
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