Structure and dynamics of Oxide Melts and Glasses : a view from multinuclear and high temperature NMR

Solid State Nuclear Magnetic Resonance (NMR) experiments allow characterizing the local structure and dynamics of oxide glasses and melts. Thanks to the development of new experiments, it now becomes possible to evidence not only the details of the coordination state of the network formers of glasses but also to characterize the nature of polyatomic molecular motifs extending over several chemical bonds. We present results involving 31P homonuclear experiments that allow description of groups of up to three phosphate units and 27Al/17O heteronuclear that allows evidencing μ3 oxygen bridges in aluminate glasses and rediscussion of the structure of high temperature melts.Comment: Journal of Non-Crystalline Solids (2007) in press; Also available online at: http://crmht.cnrs-orleans.fr/Intranet/Publications/?id=207

Origins of linewidth in ¹H magic-angle spinning NMR

A detailed study of the factors determining the linewidth (and hence resolution) in 1H solid-state magic-angle spinning NMR is described. Although it has been known from the early days of magic-angle spinning (MAS) that resolution of spectra from abundant nuclear spins, such as 1H, increases approximately linearly with increasing sample rotation rate, the difficulty of describing the dynamics of extended networks of coupled spins has made it difficult to predict a priori the resolution expected for a given sample. Using recently developed, highly efficient methods of numerical simulation, together with experimental measurements on a variety of test systems, we propose a comprehensive picture of 1H resolution under MAS. The "homogeneous" component of the linewidth is shown to depend primarily on the ratio between an effective local coupling strength and the spin rate, modified by geometrical factors which loosely correspond to the "dimensionality" of the coupling network. The remaining "inhomogeneous" component of the natural linewidth is confirmed to have the same properties as in dilute-spin NMR. Variations in the NMR frequency due to chemical shift effects are shown to have minimal impact on 1H resolution. The implications of these results for solid-state NMR experiments involving 1H and other abundant-spin nuclei are discussed

Novel bicyclic hexanuclear copper(I) aggregate: Structure and solid state 31P CPMAS NMR spectra of [(Cu3L3)2] and [Cu(PPh3)2L] complexes of N-(diisopropoxythiophosphinyl)-N′-phenylthiourea (HL)

A new complex of N-thiophosphorylthiourea PhNHC(S)NHP(S)(OiPr)2 (HL) of formula [(Cu3L3)2] has been synthesized and characterized by single crystal X-ray diffraction, FT-IR, 1H, 31P NMR in solution and by 31P CPMAS NMR spectroscopy in the solid state. A comparison of the structure and the spectral parameters of [(Cu3L3)2] with those of the mononuclear analogue [Cu(PPh3)2L] was performed. In the solid state the aggregate [(Cu3L3)2] represents the first example of a spontaneous "side-by-side" association of two neutral cyclic [Cu3L3] moieties using two Cu-S-Cu bridges formed by the sulfur atoms of the PS-groups. The values of the 1J(31P-63,65Cu) and 2J(31P-31P) coupling constants of the [Cu(PPh3)2]+ moiety in the solid state spectra are reported. © 2008 Elsevier B.V. All rights reserved

The response of pre-osteoblasts and osteoclasts to gallium containing mesoporous bioactive glasses.

Mesoporous bioactive glasses (MBGs) in the system SiO2-CaO-P2O5-Ga2O3 have been synthesized by the evaporation induced self-assembly method and subsequent impregnation with Ga cations. Two different compositions have been prepared and the local environment of Ga(III) has been characterized using 29Si, 71Ga and 31P NMR analysis, demonstrating that Ga(III) is efficiently incorporated as both, network former (GaO4 units) and network modifier (GaO6 units). In vitro bioactivity tests evidenced that Ga-containing MBGs retain their capability for nucleation and growth of an apatite-like layer in contact with a simulated body fluid with ion concentrations nearly equal to those of human blood plasma. Finally, in vitro cell culture tests evidenced that Ga incorporation results in a selective effect on osteoblasts and osteoclasts. Indeed, the presence of this element enhances the early differentiation towards osteoblast phenotype while disturbing osteoclastogenesis. Considering these results, Ga-doped MBGs might be proposed as bone substitutes, especially in osteoporosis scenarios

Copper(i) complexes with N-(diisopropoxythiophosphoryl)thiobenzamide PhC(S)NHP(S)(OiPr)2

Reaction of the potassium salt of N-thiophosphorylthiobenzamide PhC(S)NHP(S)(OiPr)2 (HL) with CuI in aqueous EtOH leads to the tetranuclear [Cu4L4] and the polynuclear [KCuL 2]n complexes, while the same reactions using the lithium or sodium salts of HL exclusively lead to the tetramer [Cu4L 4]. Reaction of KL with the mixture of CuI and 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) leads to the mononuclear complexes [Cu(bpy)L] and [Cu(phen)L]. The same complexes were obtained by the reaction of [Cu4L4] with bpy or phen. © 2010 The Royal Society of Chemistry

Complexes of N-thiophosphorylthioureas (HL) with copper(I). Crystal structures of [Cu3L3] and [Cu(PPh3) 2L] chelates

Reaction of the potassium salts of N-thiophosphorylated thioureas of common formula RC(S)NHP(S)(OiPr)2 [R = morpholin-N-yl (HLa), piperidin-N-yl (HLb), NH2 (HLc), PhCH 2NH (HLd)] with Cu(PPh3)3I in aqueous EtOH/CH2Cl2 leads to mononuclear [Cu(PPh 3)2L-S,S′] complexes. Using copper(i) iodide instead of Cu(PPh3)3I, polynuclear complexes [Cu n(L-S,S′)n] were obtained. The structures of these compounds were investigated by ES-MS, elemental analyses, 1H and 31P NMR in solution, IR and 31P solid-state MAS NMR spectroscopy. The crystal structures of [Cu3L3 a] and [Cu(PPh3)2Lb] were determined by single-crystal X-ray diffraction. © The Royal Society of Chemistry 2007

J Clin Med

In cystic fibrosis (CF), cystic fibrosis transmembrane regulator (CFTR) dysfunction leads to digestive disorders that promote intestinal inflammation and dysbiosis enhancing gastrointestinal symptoms. In pancreatic insufficiency CF patients, both intestinal inflammation and dysbiosis, are associated with an increase in the fecal calprotectin (FC) level. However, associations between the FC level, gastrointestinal symptoms, and quality of life (QoL) remain poorly studied. We aimed to assess such associations in pancreatic insufficiency CF children. The FC level was measured in pancreatic insufficiency CF children's stool samples. Children and their parents completed two questionnaires: The Gastrointestinal Symptoms Scales 3.0-PedsQL(TM) and the Quality of Life Pediatric Inventory 4.0-PedsQL(TM). Lower scores indicated worse symptomatology or QoL. Thirty-seven CF children were included. A FC level above 250 µg/g was associated with worse gastrointestinal symptoms and QoL scores. The FC level was inversely correlated with several gastrointestinal scores assessed by children (i.e., Total, "Heart Burn Reflux", "Nausea and Vomiting", and "Gas and Bloating"). Several QoL scores were correlated with gastrointestinal scores. The FC level was weakly associated with clinical parameters. Some gastrointestinal and QoL scores were related to disease severity associated parameters. In CF, the FC level, biomarker previously related to intestinal inflammation and dysbiosis, was associated with worse digestive symptoms and QoL scores

A Numerical Model of the SEIS Leveling System Transfer Matrix and Resonances: Application to SEIS Rotational Seismology and Dynamic Ground Interaction

Abstract Both sensors of the SEIS instrument (VBBs and SPs) are mounted on the mechanical leveling system (LVL), which has to ensure a level placement on the Martian ground under currently unknown local conditions, and provide the mechanical coupling of the seismometers to the ground. We developed a simplified analytical model of the LVL structure in order to reproduce its mechanical behavior by predicting its resonances and transfer function. This model is implemented numerically and allows to estimate the effects of the LVL on the data recorded by the VBBs and SPs on Mars. The model is validated through comparison with the horizontal resonances (between 35 and 50 Hz) observed in laboratory measurements. These modes prove to be highly dependent of the ground horizontal stiffness and torque. For this reason, an inversion study is performed and the results are compared with some experimental measurements of the LVL feet’s penetration in a martian regolith analog. This comparison shows that the analytical model can be used to estimate the elastic ground properties of the InSight landing site. Another application consists in modeling the 6 sensors on the LVL at their real positions, also considering their sensitivity axes, to study the performances of the global SEIS instrument in translation and rotation. It is found that the high frequency ground rotation can be measured by SEIS and, when compared to the ground acceleration, can provide ways to estimate the phase velocity of the seismic surface waves at shallow depths. Finally, synthetic data from the active seismic experiment made during the HP3 penetration and SEIS rotation noise are compared and used for an inversion of the Rayleigh phase velocity. This confirms the perspectives for rotational seismology with SEIS which will be developed with the SEIS data acquired during the commissioning phase after landing

NMR-Based Structural Modeling of Graphite Oxide Using Multidimensional 13C Solid-State NMR and ab Initio Chemical Shift Calculations

Chemically modified graphenes and other graphite-based materials have attracted growing interest for their unique potential as lightweight electronic and structural nanomaterials. It is an important challenge to construct structural models of noncrystalline graphite-based materials on the basis of NMR or other spectroscopic data. To address this challenge, a solid-state NMR (SSNMR)-based structural modeling approach is presented on graphite oxide (GO), which is a prominent precursor and interesting benchmark system of modified graphene. An experimental 2D C-13 double-quantum/single-quantum correlation SSNMR spectrum of C-13-labeled GO was compared with spectra simulated for different structural models using ab initio geometry optimization and chemical shift calculations. The results show that the spectral features of the GO sample are best reproduced by a geometry-optimized structural model that is based on the Lerf-Klinowski model (Lerf, A. et al. Phys. Chem. B 1998, 102, 4477); this model is composed of interconnected sp(2), 1,2-epoxide, and COH carbons. This study also convincingly excludes the possibility of other previously proposed models, including the highly oxidized structures involving 1,3-epoxide carbons (Szabo, I. et al. Chem. Mater. 2006, 18, 2740). C-13 chemical shift anisotropy (CSA) patterns measured by a 2D C-13 CSA/isotropic shift correlation SSNMR were well reproduced by the chemical shift tensor obtained by the ab initio calculation for the former model. The approach presented here is likely to be applicable to other chemically modified graphenes and graphite-based systems

Critical Role of Macrophages and Their Activation via MyD88-NFκB Signaling in Lung Innate Immunity to Mycoplasma pneumoniae

Mycoplasma pneumoniae (Mp), a common cause of pneumonia, is associated with asthma; however, the mechanisms underlying this association remain unclear. We investigated the cellular immune response to Mp in mice. Intranasal inoculation with Mp elicited infiltration of the lungs with neutrophils, monocytes and macrophages. Systemic depletion of macrophages, but not neutrophils, resulted in impaired clearance of Mp from the lungs. Accumulation and activation of macrophages were decreased in the lungs of MyD88−/− mice and clearance of Mp was impaired, indicating that MyD88 is a key signaling protein in the anti-Mp response. MyD88-dependent signaling was also required for the Mp-induced activation of NFκB, which was essential for macrophages to eliminate the microbe in vitro. Thus, MyD88-NFκB signaling in macrophages is essential for clearance of Mp from the lungs