11 research outputs found

    Synthesis, characterization and quantum-chemical analysis of {FeNO}7 compounds with oxygen-donor ligands

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    Synthesis, characterization and quantum-chemical analysis of {FeNO}7 compounds with oxygen-donor ligands

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    “Brown‐Ring”‐Related Coordination Polymers of the Quartet‐{FeNO}7 Chromophore

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    A conspicuous detail of the so‐called brown‐ring test (the analytical test on nitrate) is the reddish color of the bottom layer of concentrated sulfuric acid, which develops upon the bleeding of the brown layer into the acid. Crystals of the same color form from a solution of ferrous sulfate in concentrated sulfuric acid on saturation with gaseous nitric oxide. The structure of this H3O[{Fe(NO)(ÎŒ4‐SO4)(ÎŒ2‐SO4)0.5}n/n] (1a) is made up from infinite chessboard‐type layers with sulfur on the field junctions and Fe(NO) moieties below the black and above the white fields. An Fe–N–O angle of about 160° causes disorder in the tetragonal space group I4/mmm. A similar crystal pathology was found in the related [{Fe(MeOH)(NO)(ÎŒ4‐SO4)}n/n] (1b) in the same crystal class. A one‐dimensional coordination polymer is formed in crystals of a third compound that comprises the Fe(NO)O5 coordination pattern, namely the brown oxalato species [{Fe(H2O)(NO)(ÎŒ2‐ox)}n/n·H2O] (2). A still larger NO tilt of about 156° is not obscured by disorder in the triclinic crystals of 2

    Not Guilty on Every Count: The “Non‐Innocent” Nitrosyl Ligand in the Framework of IUPACâ€Čs Oxidation‐State Formalism

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    Nitrosyl–metal bonding relies on the two interactions between the pair of N–O‐π* and two of the metal's d orbitals. These (back)bonds are largely covalent, which makes their allocation in the course of an oxidation‐state determination ambiguous. However, apart from M‐N‐O‐angle or net‐charge considerations, IUPACâ€Čs “ionic approximation” is a useful tool to reliably classify nitrosyl metal complexes in an orbital‐centered approach

    Silent brain infarcts impact on cognitive function in atrial fibrillation

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    Aims: We aimed to investigate the association of clinically overt and silent brain lesions with cognitive function in atrial fibrillation (AF) patients. Methods and results: We enrolled 1227 AF patients in a prospective, multicentre cohort study (Swiss-AF). Patients underwent standardized brain magnetic resonance imaging (MRI) at baseline and after 2 years. We quantified new small non-cortical infarcts (SNCIs) and large non-cortical or cortical infarcts (LNCCIs), white matter lesions (WML), and microbleeds (Mb). Clinically, silent infarcts were defined as new SNCI/LNCCI on follow-up MRI in patients without a clinical stroke or transient ischaemic attack (TIA) during follow-up. Cognition was assessed using validated tests. The mean age was 71 years, 26.1% were females, and 89.9% were anticoagulated. Twenty-eight patients (2.3%) experienced a stroke/TIA during 2 years of follow-up. Of the 68 (5.5%) patients with ≄1 SNCI/LNCCI, 60 (88.2%) were anticoagulated at baseline and 58 (85.3%) had a silent infarct. Patients with brain infarcts had a larger decline in cognition [median (interquartile range)] changes in Cognitive Construct score [-0.12 (-0.22; -0.07)] than patients without new brain infarcts [0.07 (-0.09; 0.25)]. New WML or Mb were not associated with cognitive decline. Conclusion: In a contemporary cohort of AF patients, 5.5% had a new brain infarct on MRI after 2 years. The majority of these infarcts was clinically silent and occurred in anticoagulated patients. Clinically, overt and silent brain infarcts had a similar impact on cognitive decline. Clinical trial registration: ClinicalTrials.gov Identifier: NCT02105844, https://clinicaltrials.gov/ct2/show/NCT02105844. Keywords: Atrial fibrillation; Brain infarction; Cognitive function; Magnetic resonance imaging; Oral anticoagulation

    Weight history over a forty-year time period

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    BACKGROUND: Mortality and disease risk assessments consider body mass index (BMI), among other parameters. Nowadays optimal BMI is discussed controversially as risk assessments are usually performed using BMI of arbitrarily chosen age points. A more comprehensive approach could be based on BMI history. However, longitudinal studies investigating BMI are rare. OBJECTIVES: To determine pragmatically different weight history patterns over forty years. DESIGN: Longitudinal study with four follow-ups over forty years, elucidating risk factors for peripheral vessel diseases as the original goal. SUBJECTS: There were 343 male subjects whose weight was measured both at baseline and at follow-ups. RESULTS: Based on pragmatic methods the following eight patterns were found: "stable" (24.8%), "stable and increasing" (28.6%), "stable and decreasing" (9.0%), "hill" (10.0%), "valley" (7.0%), "yo-yo" (14.0%), continually "increasing" (6.4%%), and continually "decreasing" (0.3%). In subjects over 45 years at baseline, stable patterns were most frequent (42%), and descending patterns became more prominent. CONCLUSIONS: The determination of different weight history patterns in a longitudinal study is possible with the use of a pragmatic procedure. Applying such weight history patterns to the mortality risk assessment of overweight could add new aspects to that risk assessment

    Operando Characterization of Intermediates Produced in a Lithium-Sulfur Battery

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    One of the technological barriers to electrification of transport is the insufficient storage capacity of the Li-ion batteries on which the current electric cars are based. The lithium-sulfur (Li-S) battery is an advanced technology whose successful commercialization can lead to significant gains in the storage capacity of batteries and promote wide-spread adoption of electric vehicles. Recently, important Li-S intermediates, including polysulfides, S3(center dot-), and Li2S, have been shown to present unique X-ray absorption near edge structure (XANES) features at the sulfur K-edge. As a result, a combination of XANES characterization with electrochemistry has the potential to contribute to the understanding of Li-S chemistry. In this study, we present an operando XANES cell design, benchmark its electrochemical and spectroscopic performance, and use it to track reaction intermediates during the discharge of the battery. In particular, by employing electrolyte solvents with either a high or a low dielectric constant, we investigate the influence of the solvent on the conversion of polysulfide species to Li2S. Our results reveal that Li2S is already formed after similar to 25-30% discharge in both types of electrolyte solvents, but that further conversion of polysulfides to Li2S proceeds more rapidly in a solvent with a low dielectric constant

    Design of the Swiss Atrial Fibrillation Cohort Study (Swiss-AF): structural brain damage and cognitive decline among patients with atrial fibrillation

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    BACKGROUND: Several studies found that patients with atrial fibrillation (AF) have an increased risk of cognitive decline and dementia over time. However, the magnitude of the problem, associated risk factors and underlying mechanisms remain unclear. METHODS: This article describes the design and methodology of the Swiss Atrial Fibrillation (Swiss-AF) Cohort Study, a prospective multicentre national cohort study of 2400 patients across 13 sites in Switzerland. Eligible patients must have documented AF. Main exclusion criteria are the inability to provide informed consent and the presence of exclusively short episodes of reversible forms of AF. All patients undergo extensive phenotyping and genotyping, including repeated assessment of cognitive functions, quality of life, disability, electrocardiography and cerebral magnetic resonance imaging. We also collect information on health related costs, and we assemble a large biobank. Key clinical outcomes in Swiss-AF are death, stroke, systemic embolism, bleeding, hospitalisation for heart failure and myocardial infarction. Information on outcomes and updates on other characteristics are being collected during yearly follow-up visits. RESULTS: Up to 7 April 2017, we have enrolled 2133 patients into Swiss-AF. With the current recruitment rate of 15 to 20 patients per week, we expect that the target sample size of 2400 patients will be reached by summer 2017. CONCLUSION: Swiss-AF is a large national prospective cohort of patients with AF in Switzerland. This study will provide important new information on structural and functional brain damage in patients with AF and on other AF related complications, using a large variety of genetic, phenotypic and health economic parameters

    Relationships of Overt and Silent Brain Lesions With Cognitive Function in Patients With Atrial Fibrillation

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    Patients with atrial fibrillation (AF) have an increased risk of cognitive decline, potentially resulting from clinically unrecognized vascular brain lesions.; This study sought to assess the relationships between cognitive function and vascular brain lesions in patients with AF.; Patients with known AF were enrolled in a multicenter study in Switzerland. Brain magnetic resonance imaging (MRI) and cognitive testing using the Montreal Cognitive Assessment (MoCA) were performed in all participants. Large noncortical or cortical infarcts (LNCCIs), small noncortical infarcts (SNCIs), microbleeds, and white matter lesions were quantified by a central core laboratory. Clinically silent infarcts were defined as infarcts on brain MRI in patients without a clinical history of stroke or transient ischemic attack.; The study included 1,737 patients with a mean age of 73 ± 8 years (28% women, 90% taking oral anticoagulant agents). On MRI, LNCCIs were found in 387 patients (22%), SNCIs in 368 (21%), microbleeds in 372 (22%), and white matter lesions in 1715 (99%). Clinically silent infarcts among the 1,390 patients without a history of stroke or transient ischemic attack were found in 201 patients with LNCCIs (15%) and 245 patients with SNCIs (18%). The MoCA score was 24.7 ± 3.3 in patients with and 25.8 ± 2.9 in those without LNCCIs on brain MRI (p < 0.001). The difference in MoCA score remained similar when only clinically silent LNCCIs were considered (24.9 ± 3.1 vs. 25.8 ± 2.9; p < 0.001). In a multivariable regression model including all vascular brain lesion parameters, LNCCI volume was the strongest predictor of a reduced MoCA (ÎČ = -0.26; 95% confidence interval: -0.40 to -0.13; p < 0.001).; Patients with AF have a high burden of LNCCIs and other brain lesions on systematic brain MRI screening, and most of these lesions are clinically silent. LNCCIs were associated with worse cognitive function, even among patients with clinically silent infarcts. Our findings raise the question of MRI screening in patients with AF

    Silent brain infarcts impact on cognitive function in atrial fibrillation

    Get PDF
    Aims: We aimed to investigate the association of clinically overt and silent brain lesions with cognitive function in atrial fibrillation (AF) patients. Methods and results: We enrolled 1227 AF patients in a prospective, multicentre cohort study (Swiss-AF). Patients underwent standardized brain magnetic resonance imaging (MRI) at baseline and after 2 years. We quantified new small non-cortical infarcts (SNCIs) and large non-cortical or cortical infarcts (LNCCIs), white matter lesions (WML), and microbleeds (Mb). Clinically, silent infarcts were defined as new SNCI/LNCCI on follow-up MRI in patients without a clinical stroke or transient ischaemic attack (TIA) during follow-up. Cognition was assessed using validated tests. The mean age was 71 years, 26.1% were females, and 89.9% were anticoagulated. Twenty-eight patients (2.3%) experienced a stroke/TIA during 2 years of follow-up. Of the 68 (5.5%) patients with ≄1 SNCI/LNCCI, 60 (88.2%) were anticoagulated at baseline and 58 (85.3%) had a silent infarct. Patients with brain infarcts had a larger decline in cognition [median (interquartile range)] changes in Cognitive Construct score [-0.12 (-0.22; -0.07)] than patients without new brain infarcts [0.07 (-0.09; 0.25)]. New WML or Mb were not associated with cognitive decline. Conclusion: In a contemporary cohort of AF patients, 5.5% had a new brain infarct on MRI after 2 years. The majority of these infarcts was clinically silent and occurred in anticoagulated patients. Clinically, overt and silent brain infarcts had a similar impact on cognitive decline
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