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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Gaulton, Kyle J, et al.
(författare)
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Genetic fine mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci.
- 2015
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 47:12, s. 1415-1415
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Tidskriftsartikel (refereegranskat)abstract
- We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease.
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| 4. |
- Scott, Robert A., et al.
(författare)
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An Expanded Genome-Wide Association Study of Type 2 Diabetes in Europeans
- 2017
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 66:11, s. 2888-2902
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Tidskriftsartikel (refereegranskat)abstract
- To characterize type 2 diabetes (T2D)-associated variation across the allele frequency spectrum, we conducted a meta-analysis of genome-wide association data from 26,676 T2D case and 132,532 control subjects of European ancestry after imputation using the 1000 Genomes multiethnic reference panel. Promising association signals were followed up in additional data sets (of 14,545 or 7,397 T2D case and 38,994 or 71,604 control subjects). We identified 13 novel T2D-associated loci (P < 5 x 10(-8)), including variants near the GLP2R, GIP, and HLA-DQA1 genes. Our analysis brought the total number of independent T2D associations to 128 distinct signals at 113 loci. Despite substantially increased sample size and more complete coverage of low-frequency variation, all novel associations were driven by common single nucleotide variants. Credible sets of potentially causal variants were generally larger than those based on imputation with earlier reference panels, consistent with resolution of causal signals to common risk haplotypes. Stratification of T2D-associated loci based on T2D-related quantitative trait associations revealed tissue-specific enrichment of regulatory annotations in pancreatic islet enhancers for loci influencing insulin secretion and in adipocytes, monocytes, and hepatocytes for insulin action-associated loci. These findings highlight the predominant role played by common variants of modest effect and the diversity of biological mechanisms influencing T2D pathophysiology.
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| 5. |
- Jansen, Willemijn J, et al.
(författare)
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Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia.
- 2018
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 75:1, s. 84-95
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials.To investigate whether amyloid-β aggregation is associated with cognitive functioning in persons without dementia.This cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017.Global cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score ≤27 or memory z score≤-1.28) and to assess whether this association was moderated by age, sex, educational level, or apolipoprotein E genotype.Among 2908 persons with normal cognition (mean [SD] age, 67.4 [12.8] years), amyloid positivity was associated with low memory scores after age 70 years (mean difference in amyloid positive vs negative, 4% [95% CI, 0%-7%] at 72 years and 21% [95% CI, 10%-33%] at 90 years) but was not associated with low MMSE scores (mean difference, 3% [95% CI, -1% to 6%], P=.16). Among 4133 patients with MCI (mean [SD] age, 70.2 [8.5] years), amyloid positivity was associated with low memory (mean difference, 16% [95% CI, 12%-20%], P<.001) and low MMSE (mean difference, 14% [95% CI, 12%-17%], P<.001) scores, and this association decreased with age. Low cognitive scores had limited utility for screening of amyloid positivity in persons with normal cognition and those with MCI. In persons with normal cognition, the age-related increase in low memory score paralleled the age-related increase in amyloid positivity with an intervening period of 10 to 15 years.Although low memory scores are an early marker of amyloid positivity, their value as a screening measure for early AD among persons without dementia is limited.
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| 6. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis.
- 2015
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Ingår i: JAMA. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 313:19, s. 1924-38
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early pathological event in Alzheimer disease (AD), starting decades before dementia onset. Estimates of the prevalence of amyloid pathology in persons without dementia are needed to understand the development of AD and to design prevention studies.
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| 7. |
- Lundqvist, Maria J., et al.
(författare)
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Calculated optoelectronic properties of Ruthenium tris-bipyridine dyes containing oligophenyleneethynylene rigid rod linkers in different chemical environments
- 2007
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 111:8, s. 1487-1497
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Tidskriftsartikel (refereegranskat)abstract
- Ruthenium tris-bipyridine dyes containing oligophenyleneethynylene (OPE) rigid rod linker groups ([Ru(bpy)3]2+, [Ru(bpy)2bpy-E-Ipa]2+, [Ru(bpy)2bpy-E-Ph-E-Ipa]2+, and [Ru(bpy)2bpy-E-Bco-E-Ipa]2+, where bpy = 2,2'-bipyridine, E = ethynylene, Ph = p-phenylene, Bco = bicyclo[2.2.2]octylene, and Ipa = isophthalic acid) have been investigated using DFT and TD-DFT calculations to elucidate the influence of the rigid rod on their optoelectronic properties. Experimentally observed differences in the optical absorption for the different complexes are discussed on the basis of TD-DFT simulated absorption spectra. A comparison of the calculated optoelectronic properties of [Ru(bpy)2bpy-E-Ph-E-Ipa]2+ in different chemical environments, that is, in different solvents and with or without counter ions, suggests that both the absorption spectra and the redox properties of the dyes with OPE rods are sensitive to the environment. The calculations show that spurious low-energy charge-transfer excitations present in the TD-DFT calculations of the extended systems in vacuum are removed when the environment is included in the calculations.
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| 8. |
- Munoz-Garcia, Ana Belen, et al.
(författare)
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Dye-sensitized solar cells strike back
- 2021
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Ingår i: Chemical Society Reviews. - : Royal Society of Chemistry. - 0306-0012 .- 1460-4744. ; 50:22, s. 12450-12550
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Forskningsöversikt (refereegranskat)abstract
- Dye-sensitized solar cells (DSCs) are celebrating their 30th birthday and they are attracting a wealth of research efforts aimed at unleashing their full potential. In recent years, DSCs and dye-sensitized photoelectrochemical cells (DSPECs) have experienced a renaissance as the best technology for several niche applications that take advantage of DSCs' unique combination of properties: at low cost, they are composed of non-toxic materials, are colorful, transparent, and very efficient in low light conditions. This review summarizes the advancements in the field over the last decade, encompassing all aspects of the DSC technology: theoretical studies, characterization techniques, materials, applications as solar cells and as drivers for the synthesis of solar fuels, and commercialization efforts from various companies.
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| 9. |
- Abrahamsson, Malin L. A.
(författare)
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Electron Transfer in Ruthenium-Manganese Complexes for Artificial Photosynthesis : Studies in Solution and on Electrode Surfaces
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In today’s society there is an increasing need for energy, an increase which for the most part is supplied by the use of fossil fuels. Fossil fuel resources are limited and their use has harmful effects on the environment, therefore the development of technologies that produce clean energy sources is very appealing. Natural photosynthesis is capable of converting solar energy into chemical energy through a series of efficient energy and electron transfer reactions with water as the only electron source. Thus, constructing an artificial system that uses the same principles to convert sunlight into electricity or storable fuels like hydrogen is one of the major forces driving artificial photosynthesis research.This thesis describes supramolecular complexes with the intention of mimicking the electron transfer reactions of the donor side in Photosystem II, where a manganese cluster together with a tyrosine catalyses the oxidation of water. All complexes are based on Ru(II)-trisbipyridine as a photosensitizer that is covalently linked to electron donors like tyrosine or manganese. Photochemical reactions are studied with time-resolved transient absorption and emission measurements. Electrochemical techniques are used to study the electrochemical behavior, and different photoelectrochemical techniques are used to investigate the complexes adsorbed onto titanium dioxide surfaces. In all complexes, intramolecular electron transfer occurs from the linked donor to photo-oxidized Ru(III). It is also observed that coordinated Mn(II) quenches the excited state of Ru(II), a reaction that is found to be distance dependent. However, by modifying one of the complexes, its excited state properties can be tuned in a way that decreases the quenching and keeps the electron transfer properties. The obtained results are of significance for the development of multinuclear Ru-Mn complexes that are capable of multi-electron transfer.
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| 10. |
- Farnum, Byron H., et al.
(författare)
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Flash-Quench Technique Employed To Study the One-Electron Reduction of Triiodide in Acetonitrile : Evidence for a Diiodide Reaction Product
- 2010
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 49:22, s. 10223-10225
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Tidskriftsartikel (refereegranskat)abstract
- The one-electron reduction of triiodide (I3?) by a reduced ruthenium polypyridyl compound was studied in an acetonitrile solution with the flash-quench technique. Reductive quenching of the metal-to-ligand charge-transfer excited state of [RuII(deeb)3]2+ by iodide generated the reduced ruthenium compound [RuII(deeb?)(deeb)2]+ and diiodide (I2??). The subsequent reaction of [RuII(deeb?)(deeb)2]+ with I3? indicated that I2?? was a product that appeared with a second-order rate constant of (5.1 ± 0.2) ? 109 M?1 s?1. After correction for diffusion and some assumptions, Marcus theory predicted a formal potential of ?0.58 V (vs SCE) for the one-electron reduction of I3?. The relevance of this reaction to solar energy conversion is discussed.
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