Delamination of Layered Covalent Organic Frameworks Berlanga, Isadora; Ruiz-González, Maria Luisa; González-Calbet, José María ...
Small (Weinheim an der Bergstrasse, Germany),
May 9, 2011, Letnik:
7, Številka:
9
Journal Article
Recenzirano
The isolation of nanostructures consisting of 10–25 layers of a covalent organic framework is confirmed by AFM carried out on several surfaces. This is achieved by means of selective ultrasound ...exfoliation on the bulk layered material. TEM demonstrates the porous nature of the free‐standing layers on a carbon gird. The chemical composition of this novel 2D polymer is determined by infrared, X‐ray photoelectron, and electron‐energy‐loss spectroscopy.
We report herein an efficient, fast, and simple synthesis of an imine‐based covalent organic framework (COF) at room temperature (hereafter, RT‐COF‐1). RT‐COF‐1 shows a layered hexagonal structure ...exhibiting channels, is robust, and is porous to N2 and CO2. The room‐temperature synthesis has enabled us to fabricate and position low‐cost micro‐ and submicropatterns of RT‐COF‐1 on several surfaces, including solid SiO2 substrates and flexible acetate paper, by using lithographically controlled wetting and conventional ink‐jet printing.
Printed crystals: An efficient, fast and simple synthesis of an imine‐based porous covalent organic framework (COF) at room temperature is reported. The room‐temperature synthesis enables fabricating micro‐ and submicropatterns of this COF on a variety of surfaces by ink‐jet printing and wet lithographically techniques.
Human mitochondrial DNA (mtDNA) shows extensive within population sequence variability. Many studies suggest that mtDNA variants may be associated with ageing or diseases, although mechanistic ...evidence at the molecular level is lacking. Mitochondrial replacement has the potential to prevent transmission of disease-causing oocyte mtDNA. However, extension of this technology requires a comprehensive understanding of the physiological relevance of mtDNA sequence variability and its match with the nuclear-encoded mitochondrial genes. Studies in conplastic animals allow comparison of individuals with the same nuclear genome but different mtDNA variants, and have provided both supporting and refuting evidence that mtDNA variation influences organismal physiology. However, most of these studies did not confirm the conplastic status, focused on younger animals, and did not investigate the full range of physiological and phenotypic variability likely to be influenced by mitochondria. Here we systematically characterized conplastic mice throughout their lifespan using transcriptomic, proteomic,metabolomic, biochemical, physiological and phenotyping studies. We show that mtDNA haplotype profoundly influences mitochondrial proteostasis and reactive oxygen species generation,insulin signalling, obesity, and ageing parameters including telomere shortening and mitochondrial dysfunction, resulting in profound differences in health longevity between conplastic strains.
Structural instabilities can be used to provide rapid responses activated by mechanical force or displacement thresholds. The emergence of responsive materials has opened the door for adapting such ...structural instabilities to actuators that will abruptly deform guided by external stimuli. However, fast configurational transitions between equilibrium states imply important viscoelastic roles at the material level that inevitably scale up to the structural level. A comprehensive understanding of viscoelastic effects is provided on bistable structural transitions combining a new experimental perspective and a thorough modeling analysis. The insights from these results are here translated to magneto‐responsive bistable structures offering a route‐map to design effective actuation conditions. The bistable transition functionally depends on the combination of magnetic field amplitude and application rate. The understanding of the viscoelastic and magneto‐mechanical coupling provides efficient actuation via temporal magnetic pulses, removing the need of generating continued magnetic fields. Finally, these insights are combined to develop a responsive structure whose transient and steady bistable transitions can be modulated by the application rate of external magnetic stimuli.
Viscoelastic mechanisms are demonstrated valuable designing variables to conceptualize bistable structures with rate‐dependent actuation modes. The viscoelastic response of beam components is simulated by an original constitutive beam‐element formulation. Based on these viscoelastic insights, magneto‐responsive structural components are developed. The transient and steady bistable transitions of these structures can be modulated by the application rate of external magnetic stimuli.
Mixed‐anion compounds widen the chemical space of attainable materials compared to single anionic compounds, but the exploration of their structural diversity is limited by common synthetic paths. ...Especially, oxychlorides rely mainly on layered structures, which suffer from low stability during photo(electro)catalytic processes. Herein we report a strategy to design a new polar 3D tetrahedral framework with composition Zn4Si2O7Cl2. We use a molten salt medium to enable low temperature crystallization of nanowires of this new compound, by relying on tetrahedral building units present in the melt to build the connectivity of the oxychloride. These units are combined with silicon‐based connectors from a non‐oxidic Zintl phase to enable precise tuning of the oxygen content. This structure brings high chemical and thermal stability, as well as strongly anisotropic hole mobility along the polar axis. These features, associated with the ability to adjust the transport properties by doping, enable to tune water splitting properties for photoelectrocatalytic H2 evolution and water oxidation. This work then paves the way to a new family of mixed‐anion solids
Nanowires of the new oxychloride Zn4Si2O7Cl2 crystallize from molten salts as a polar three‐dimensional tetrahedral framework. They exhibit strongly anisotropic charge carrier mobility, adjustable electrical properties, and photoelectrochemical properties for H2 production from water.
Poor insight is a major problem in psychosis, being detrimental for treatment compliance and recovery. Previous studies have identified various correlates of insight impairment, mostly in chronic ...samples. The current study aimed to determine clinical, neurocognitive, metacognitive, and socio-cognitive predictors of insight in first-episode psychosis.
Regression analyses of different insight dimensions were conducted in 190 patients with first-episode psychosis. Measures of clinical symptoms, neurocognition, metacognition, social cognition, and ‘jumping to conclusions’ bias were entered as predictors.
Delusions, disorganisation, and certain negative symptoms were associated with unawareness in various domains, while depression was associated with greater awareness of illness. Deficit in theory of mind and self-reflective processes, as well as a ‘jumping to conclusions’ bias, contributed to poor insight. Several neuropsychological scores also contributed to this but their contribution was no longer observed in regression analyses that included all the previously identified clinical and cognitive predictors. A measure of perseverative errors was still associated with unawareness and misattribution of symptoms.
In models that account for 28 % to 50 % of the variance, poor insight in first-episode psychosis is mainly associated with delusions and certain negative symptoms. At the cognitive level it does not appear to result from neuropsychological impairment but rather from altered reasoning bias and dysfunction in metacognitive processes. Therapeutic strategies specifically directed at these mechanisms could help improve the evolution of insight in first episode psychosis.
•It is crucial to understand the bases of insight deficit in psychosis.•Gender differences in the manifestations and correlates of psychosis have been repeatedly observed.•Strong gender differences ...emerged in the clinical and metacognitive predictors of insight.•Gender specific cognitive remediation strategies should be developed.
We aimed to explore gender-related differences in the associations of insight impairment with clinical symptoms, metacognition, and social cognition in psychosis.
Regression analysis of several clinical insight dimensions was conducted on the data from 116 men and 56 women with first-episode psychosis. Various clinical symptoms and measures of metacognition and social cognition were entered as predictors.
In both men and women, delusions emerged as a strong predictor of all insight dimensions, and verbal hallucinations as a strong predictor of symptom relabelling. In men, certain negative symptoms as well as self-certainty, lack of self-reflectiveness, impaired theory of mind, attributional biases, and a jumping-to-conclusions bias were additional predictors of poor insight, while good insight was associated with depression, anxiety, avolition, blunted affect, and impaired emotional recognition. In women, poor insight was associated with a self-serving/externalising bias, impaired emotional recognition, and attention disorders.
Poor insight in first-episode psychosis is strongly linked to deficits in metacognition and social cognition, with marked differences between men and women with respect to the specific skills involved in the impairment. Meanwhile, good insight is linked to a variety of affective manifestations in men. These findings suggest new avenues for more targeted cognitive interventions to improve clinical insight in psychosis.
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