370 research outputs found
Structural Diversity of Lithium N âMesitylâ P , P âdiphenylphosphinimidate of the type [(L)Li{OâPPh 2 =NâMes] n Depending on Lewis Base L
Abstract Metalation of N âmesitylâ P,P âdiphenylphosphinic amide with n BuLi in toluene yields tetranuclear lithium N âmesitylâ P , P âdiphenylphosphinimidate ([Ph 2 P(OLi)=NâMes] 4 , 1 ). Metalation of Ph 2 P(O)âN(H)Mes with a mixture of dibutylmagnesium and butyllithium in DME leads to formation of dinuclear [Ph 2 P{OLi(dme)}=NâMes] 2 ( 2 ). Excess of Ph 2 P(O)âN(H)Mes gives dinuclear [Li(OâPPh 2 =NâMes){Ph 2 P(=O)âN(H)âMes}] 2 ( 3 ) with threeâcoordinate alkali ions. The metathetical approach via reaction of 1 with anhydrous magnesium bromide in ethereal solution yields [{(thf)LiBr} 2 {(thf)Li(OâPPh 2 =NMes)(Et 2 O)Li(OâPPh 2 =NMes)}] ( 4 ). Heterobimetallic Li/Mg compounds are not accessible by these protocols. Reactions of 1 with DME, with excess of Ph 2 P(O)âN(H)Mes or with LiBr allows the straightforward conversion to compounds 2 , 3 and 4 .imag
Meta-analysis of generalized additive models in neuroimaging studies
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231772.pdf (publisher's version ) (Open Access)Analyzing data from multiple neuroimaging studies has great potential in terms of increasing statistical power, enabling detection of effects of smaller magnitude than would be possible when analyzing each study separately and also allowing to systematically investigate between-study differences. Restrictions due to privacy or proprietary data as well as more practical concerns can make it hard to share neuroimaging datasets, such that analyzing all data in a common location might be impractical or impossible. Meta-analytic methods provide a way to overcome this issue, by combining aggregated quantities like model parameters or risk ratios. Most meta-analytic tools focus on parametric statistical models, and methods for meta-analyzing semi-parametric models like generalized additive models have not been well developed. Parametric models are often not appropriate in neuroimaging, where for instance age-brain relationships may take forms that are difficult to accurately describe using such models. In this paper we introduce meta-GAM, a method for meta-analysis of generalized additive models which does not require individual participant data, and hence is suitable for increasing statistical power while upholding privacy and other regulatory concerns. We extend previous works by enabling the analysis of multiple model terms as well as multivariate smooth functions. In addition, we show how meta-analytic p-values can be computed for smooth terms. The proposed methods are shown to perform well in simulation experiments, and are demonstrated in a real data analysis on hippocampal volume and self-reported sleep quality data from the Lifebrain consortium. We argue that application of meta-GAM is especially beneficial in lifespan neuroscience and imaging genetics. The methods are implemented in an accompanying R package metagam, which is also demonstrated
Potassium-mediated zincation of ferrocene and ruthenocene : potassium, the architect behind supramolecular structural variations
Direct zincation of ferrocene and ruthenocene by the synergic base [PMDETA.K(ÎŒ-TMP)(ÎŒ-Me)Zn(Me)] produces the monozincated complexes [{PMDETA.K(ÎŒ-Me)2Zn(Fc)}â] and [{PMDETA.K(ÎŒ-Me)2Zn(Rc)}2] respectively, having similar monomeric (dinuclear) units but aggregating supramolecularly in very different polymeric and dimeric forms
Personal identity (de)formation among lifestyle travellers: A double-edged sword?
This article explores the personal identity work of lifestyle travellers â individuals for whom extended leisure travel is a preferred lifestyle that they return to repeatedly. Qualitative findings from in-depth semi-structured interviews with lifestyle travellers in northern India and southern Thailand are interpreted in light of theories on identity formation in late modernity that position identity as problematic. It is suggested that extended leisure travel can provide exposure to varied cultural praxes that may contribute to a sense of social saturation. Whilst a minority of the respondents embraced a saturation of personal identity in the subjective formation of a cosmopolitan cultural identity, several of the respondents were paradoxically left with more identity questions than answers as the result of their travels
Matching sensitivity to abundance: High resolution immuno-mass spectrometry imaging of lanthanide labels and endogenous elements in the murine brain
© 2020 The Royal Society of Chemistry. This work introduces a new method for immuno-mass spectrometry imaging via quadrupole-based laser ablation-inductively coupled plasma-mass spectrometry instruments that is matched to the abundance of elements in biological tissues. Manipulation of ion-optics and quadrupole mass filter parameters provided increased transmission of low level high-mass elements, which are typically used as labels for antibodies, at the expense of highly abundant endogenous low-mass elements. Transmission of mid-mass elements such as transition metals was only slightly affected. The implications for mass resolution and background signals are critically discussed and signal to noise ratios and imaging capabilities are compared to those obtained from a standard method. This novel approach resulted in a 6-fold improved signal to noise ratio for lanthanides that are routinely used as elemental labels for antibodies to target protein distributions in biological tissues. This increase in signal intensity, enhanced contrasts, lower limits of detection and the potential to improve spatial resolution contributed to enhanced imaging and trace analyses, as demonstrated by imaging murine brain sections of the hippocampal system and substantia nigra
Healthy minds 0-100 years: Optimising the use of European brain imaging cohorts ("Lifebrain").
The main objective of "Lifebrain" is to identify the determinants of brain, cognitive and mental (BCM) health at different stages of life. By integrating, harmonising and enriching major European neuroimaging studies across the life span, we will merge fine-grained BCM health measures of more than 5000 individuals. Longitudinal brain imaging, genetic and health data are available for a major part, as well as cognitive and mental health measures for the broader cohorts, exceeding 27,000 examinations in total. By linking these data to other databases and biobanks, including birth registries, national and regional archives, and by enriching them with a new online data collection and novel measures, we will address the risk factors and protective factors of BCM health. We will identify pathways through which risk and protective factors work and their moderators. Exploiting existing European infrastructures and initiatives, we hope to make major conceptual, methodological and analytical contributions towards large integrative cohorts and their efficient exploitation. We will thus provide novel information on BCM health maintenance, as well as the onset and course of BCM disorders. This will lay a foundation for earlier diagnosis of brain disorders, aberrant development and decline of BCM health, and translate into future preventive and therapeutic strategies. Aiming to improve clinical practice and public health we will work with stakeholders and health authorities, and thus provide the evidence base for prevention and intervention.This research is funded by the EU Horizon 2020 Grant: âHealthy
minds 0â100 years: Optimising the use of European brain imaging
cohorts (âLifebrainâ)â. Grant agreement number: 732592. Call:
Societal challenges: Health, demographic change and well-bein
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