504 research outputs found

    Functionalisation of colloidal transition metal sulphides nanocrystals: A fascinating and challenging playground for the chemist

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    Metal sulphides, and in particular transition metal sulphide colloids, are a broad, versatile and exciting class of inorganic compounds which deserve growing interest and attention ascribable to the functional properties that many of them display. With respect to their oxide homologues, however, they are characterised by noticeably different chemical, structural and hence functional features. Their potential applications span several fields, and in many of the foreseen applications (e.g., in bioimaging and related fields), the achievement of stable colloidal suspensions of metal sulphides is highly desirable or either an unavoidable requirement to be met. To this aim, robust functionalisation strategies should be devised, which however are, with respect to metal or metal oxides colloids, much more challenging. This has to be ascribed, inter alia, also to the still limited knowledge of the sulphides surface chemistry, particularly when comparing it to the better established, though multifaceted, oxide surface chemistry. A ground-breaking endeavour in this field is hence the detailed understanding of the nature of the complex surface chemistry of transition metal sulphides, which ideally requires an integrated experimental and modelling approach. In this review, an overview of the state-of-the-art on the existing examples of functionalisation of transition metal sulphides is provided, also by focusing on selected case studies, exemplifying the manifold nature of this class of binary inorganic compounds

    Prefrontal control over motor cortex cycles at beta-frequency during movement inhibition

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    A fully adapted behavior requires maximum efficiency to inhibit processes in the motor domain [ 1 ]. Although a number of cortical and subcortical brain regions have been implicated, converging evidence suggests that activation of right inferior frontal gyrus (r-IFG) and right presupplementary motor area (r-preSMA) is crucial for successful response inhibition [ 2, 3 ]. However, it is still unknown how these prefrontal areas convey the necessary signal to the primary motor cortex (M1), the cortical site where the final motor plan eventually has to be inhibited or executed. On the basis of the widely accepted view that brain oscillations are fundamental for communication between neuronal network elements [ 4–6 ], one would predict that the transmission of these inhibitory signals within the prefrontal-central networks (i.e., r-IFG/M1 and/or r-preSMA/M1) is realized in rapid, periodic bursts coinciding with oscillatory brain activity at a distinct frequency. However, the dynamics of corticocortical effective connectivity has never been directly tested on such timescales. By using double-coil transcranial magnetic stimulation (TMS) and electroencephalography (EEG) [ 7, 8 ], we assessed instantaneous prefrontal-to-motor cortex connectivity in a Go/NoGo paradigm as a function of delay from (Go/NoGo) cue onset. In NoGo trials only, the effects of a conditioning prefrontal TMS pulse on motor cortex excitability cycled at beta frequency, coinciding with a frontocentral beta signature in EEG. This establishes, for the first time, a tight link between effective cortical connectivity and related cortical oscillatory activity, leading to the conclusion that endogenous (top-down) inhibitory motor signals are transmitted in beta bursts in large-scale cortical networks for inhibitory motor control

    Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

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    A common approach to generate tailored materials and nanoparticles (NPs) is the formation of molecular monolayers by chemisorption of bifunctional anchor molecules. This approach depends critically on the choice of a suitable anchor group. Recently, bifunctional catecholates, inspired by mussel-adhesive proteins (MAPs) and bacterial siderophores, have received considerable interest as anchor groups for biomedically relevant metal surfaces and nanoparticles. We report here the synthesis of new tripodal catecholates as multivalent anchor molecules for immobilization on metal surfaces and nanoparticles. The tripodal catecholates have been conjugated to various effector molecules such as PEG, a sulfobetaine and an adamantyl group. The potential of these conjugates has been demonstrated with the immobilization of tripodal catecholates on ZnO NPs. The results confirmed a high loading of tripodal PEG-catecholates on the particles and the formation of stable PEG layers in aqueous solution

    Genetic Variability of RXRB, PPARA, and PPARG in Wegener's Granulomatosis

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    A major genomic region involved in Wegener's granulomatosis includes the gene for retinoid receptor beta (RXRB) which forms heterodimers with peroxisome proliferator-activated receptors (PPARs). It is unclear whether this association directly arises from the RXRB allele(s) or via a linked variation. In order to reveal any hitherto unknown and potentially disease-relevant variation of the RXRB gene, we have genotyped four tagging SNPs of this genomic region and have directly sequenced selected WG patients and controls representing disease-associated haplotypes. Additionally, we have genotyped 2 SNPs each in the genes for PPARα and PPARγ (PPARA and PPARG). Hence, we confirmed the strong association of the RXRB locus with WG but could not reveal any novel variation in RXRB. None of the PPARA and PPARG SNPs showed association with WG. Moreover, no epistatic effect was seen between RXRB and PPARA/PPARG alleles. These results do not support an etiopathological role of PPAR in WG. Analyses of further genes functionally linked to RXRB may provide additional data useful to evaluate the RXRB association found in WG

    Inter-rater reliability and acceptance of the structured diagnostic interview for regulatory problems in infancy

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    Background: Regulatory problems such as excessive crying, sleeping–and feeding difficulties in infancy are some of the earliest precursors of later mental health difficulties emerging throughout the lifespan. In the present study, the inter-rater reliability and acceptance of a structured computer-assisted diagnostic interview for regulatory problems (Baby-DIPS) was investigated. Methods: Using a community sample, 132 mothers of infants aged between 3 and 18 months (mean age = 10 months) were interviewed with the Baby-DIPS regarding current and former (combined = lifetime) regulatory problems. Severity of the symptoms was also rated. The interviews were conducted face-to-face at a psychology department at the university (51.5 %), the mother’s home (23.5 %), or via telephone (25.0 %). Inter-rater reliability was assessed with Cohen’s kappa (k). A sample of 48 mothers and their interviewers filled in acceptance questionnaires after the interview. Results: Good to excellent inter-rater reliability on the levels of current and lifetime regulatory problems (k = 0.77–0.98) were found. High inter-rater agreement was also found for ratings of severity (ICC = 0.86–0.97). Participants and interviewers’ overall acceptance ratings of the computer-assisted interview were favourable. Acceptance scores did not differ between interviews that revealed one or more clinically relevant regulatory problem(s) compared to those that revealed no regulatory problems. Conclusions: The Baby-DIPS was found to be a reliable instrument for the assessment of current and lifetime problems in crying and sleeping behaviours. The computer-assisted version of the Baby-DIPS was well accepted by interviewers and mothers. The Baby-DIPS appears to be well-suited for research and clinical use to identify infant regulatory problems

    Tuning the activity of a hybrid polymer–oxocluster catalyst: A composition—selectivity correlation

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    Zr-based oxoclusters Mx_{x}Oy_{y}(OR)w_{w}(OOR’)z_{z} are promising catalysts for the activation of hydrogen peroxide. However, they need to be integrated into suitable matrices to increase their hydrolytic stability and allow for their recovery after use. Polymeric materials can be successfully employed for this aim, since they modify the properties of the resulting hybrid materials, in terms of polarity and chemical affinity for the substrates, improving the catalytic activity. Herein, we report the synthesis of different acrylic polymers based on various co-monomers (methyl methacrylate (MMA), 2,2,2-trifluoroethylmethacrylate (TFMA) and 3-methacryloxypropyltrimethoxylsilane (MAPTMS)) covalently cross-linked by a Zr4_{4}-based oxocluster, whose composition was tuned to optimise the catalytic oxidation of methyl p-tolyl sulphide. To assess their properties and stability, the materials were characterised via Fourier Transform Infrared (FT-IR) and Raman spectroscopies, Thermogravimetric Analysis (TGA), Solid-State NMR (SS-NMR) and X-Ray Absorption Spectroscopies XAS, before and after catalytic turnover

    Intact perineum : what are the predictive factors in spontaneous vaginal birth?

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    Introduction: Perineal trauma at birth is distressing for women and can cause serious short and long term morbidity. Aim: Investigate the prevalence and predictive factors of intact perineum after normal vaginal birth among Portuguese women who had spontaneous vaginal births. Methods: A descriptive, cross-sectional, retrospective study was carried out among pregnant women who had spontaneous vaginal births, between January 1, 2017, and December 31, 2017, in a single birth centre in Portugal. Following ethical approval, the prevalence of intact perineum was calculated and multivariate analysis with logistic regression was carried out, to identify the predictive factors of having an intact perineum after spontaneous vaginal birth. Results: A total of 1748 pregnant women had spontaneous vaginal births. Four hundred and forty-one women (25.2%) had intact perineum whereas in 1307 (74.8%) of women, the perineum was not intact. First-degree tears occurred in 23.2% (405/1748) of women, second-degree tears occurred in 4% (70/1748) of women while three women (0.2%) experienced a third-degree tear. The rate of episiotomies was 43.8% (766/1748). Episiotomy and first-degree tears occurred in 2.6% (45/1748), episiotomy and second-degree tears occurred in 0.7% (12/1748), while episiotomy and third-degree tears occurred in 0.3% (6/1748) of women. Having a previous caesarean section reduced the odds of intact perineum by 60%, while nulliparity reduced the odds by 70%. For every 250 grams increase in birth weight, the odds of sustaining an intact perineum were decreased by 13%. Alternative birth positions (excluding lithotomy) doubled the odds of maintaining an intact perineum. Conclusion: The prevalence of intact perineum is 25,2%. Predictive factors for intact perineum include birth weight, parity, previous caesarean section and birthing position. Recognizing these factors could support and facilitate the management of spontaneous vaginal birth to promote an intact perineum. Further research is needed to gain better understanding of this phenomenon.peer-reviewe

    Effective Space Confinement by Inverse Miniemulsion for the Controlled Synthesis of Undoped and Eu3+^{3+} -Doped Calcium Molybdate Nanophosphors: A Systematic Comparison with Batch Synthesis

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    The possibility to precisely control reaction outcomes for pursuing materials with well-defined features is a main endeavor in the development of inorganic materials. Confining reactions within a confined space, such as nanoreactors, is an extremely promising methodology which allows to ensure control over the final properties of the material. An effective room temperature inverse miniemulsion approach for the controlled synthesis of undoped and Eu3+-doped calcium molybdate crystalline nanophosphors was developed. The advantages and the efficiency of confined space in terms of controlling nanoparticle features like size, shape, and functional properties are highlighted by systematically comparing miniemulsion products with calcium molybdate particles obtained without confinement from a typical batch synthesis. A relevant beneficial impact of space confinement by miniemulsion nanodroplets is observed on the control of size and shape of the final nanoparticles, resulting in 12 nm spherical nanoparticles with a narrow size distribution, as compared to the 58 nm irregularly shaped and aggregated particles from the batch approach (assessed by TEM analysis). Further considerable effects of the confined space for the miniemulsion samples are found on the doping effectiveness, leading to a more homogeneous distribution of the Eu3+^{3+} ions into the molybdate host matrix, without segregation (assessed by PXRD, XAS, and ICP-MS). These findings are finally related to the photoluminescence properties, which are evidenced to be closely dependent on the Eu3+^{3+} content for the miniemulsion samples, as an increase of the relative intensity of the direct f–f excitation and a shortening of the lifetime (from 0.901 ms for 1 at. % to 0.625 ms for 7 at. % samples) with increasing Eu3+^{3+} content are observed, whereas no relationship between these parameters and the Eu3+^{3+} content is evidenced for the batch samples. All these results are ascribed to the uniform and controlled crystallization occurring inside each miniemulsion nanodroplet, as opposed to the less controlled nucleation and growth for a classic nonconfined approach
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