Gelation Mechanism Revealed in Organometallic Gels: Prevalence of van der Waals Interactions on Oligomerization by Coordination Chemistry.

Shaping of nanomaterials is a necessary step for their inclusion in electronic devices and batteries. For this purpose, the formulation of a moldable material including these nanomaterials is desirable. Organomineral gels are a very interesting option, since the components of the nanomaterial itself form a gel without the help of a binder.

Cordiasecosides G-J, 9,10-Seco-29-norcycloartane glycosides isolated from Cordia lutea and their antibacterial activities.

Four undescribed secocycloartane monoglycosides (1-4) were isolated from an ethanolic extract of the dry flowers of Cordia lutea Lam. Their structural assignment is based on NMR and MS analysis. Their stereochemistry is confirmed by molecular modelling studies using DFT-NMR calculations done for compound 3.

Cell stretching is amplified by active actin remodelling to deform and recruit proteins in mechanosensitive structures.

Detection and conversion of mechanical forces into biochemical signals controls cell functions during physiological and pathological processes. Mechanosensing is based on protein deformations and reorganizations, yet the molecular mechanisms are still unclear. Using a cell-stretching device compatible with super-resolution microscopy and single-protein tracking, we explored the nanoscale deformations and reorganizations of individual proteins inside mechanosensitive structures.

A sterically congested 1,2-diphosphino-1'-boryl-ferrocene: synthesis, characterization and coordination to platinum.

A new class of tritopic ferrocene-based ambiphilic compounds has been prepared by assembling diphosphino- and boryl-substituted cyclopentadienides at iron. The presence of five sterically demanding substituents on the ferrocene platform induces conformational constraints, as is apparent from XRD and NMR data, but does not prevent the chelating coordination to platinum. The Lewis acid moiety is pendant in both the free ligand and the platinum complex.

A Stable N-Hetero-Rh-Metallacyclic Silylene.

A cyclic (amino)metal-substituted dicoordinated silylene derivative has been synthesized and fully characterized. Of particular interest is that the N-hetero-Rh -metallacyclic silylene exhibits a distorted tetrahedral geometry around the rhodium atom and a considerably shortened Si-Rh bond (2.138 Å) compared to classical Si-Rh single bonds (ca.

Evidence for genuine hydrogen bonding in gold(I) complexes.

The ability of gold to act as proton acceptor and participate in hydrogen bonding remains an open question. Here, we report the synthesis and characterization of cationic gold(I) complexes featuring ditopic phosphine-ammonium (P,NH) ligands. In addition to the presence of short Au∙∙∙H contacts in the solid state, the presence of Au∙∙∙H-N hydrogen bonds was inferred by NMR and IR spectroscopies.

Room-Temperature Functionalization of N to Borylamine at a Molybdenum Complex.

Intermolecular, stepwise functionalization by BH bonds of a (triphosphine)Mo -nitrido complex generated by N splitting is reported. The imido-hydride and di-hydride-amido Mo complexes have been isolated and characterized. Addition of PinBH to the [Mo(H) (N(BPin) )] complex at room temperature results in the liberation of borylamines from the metal center.

Cyclometalated gold(iii) complexes: noticeable differences between (N,C) and (P,C) ligands in migratory insertion.

Gold(iii) complexes are garnering increasing interest for opto-electronic, therapeutic and catalytic applications. But so far, very little is known about the factors controlling their reactivity and the very influence of the ancillary ligand. This article reports the first comprehensive study on this topic.

Using Single-Protein Tracking to Study Cell Migration.

To get a complete understanding of cell migration, it is critical to study its orchestration at the molecular level. Since the recent developments in single-molecule imaging, it is now possible to study molecular phenomena at the single-molecule level inside living cells. In this chapter, we describe how such approaches have been and can be used to decipher molecular mechanisms involved in cell migration.

Cyclic (Amino)(Phosphonium Bora-Ylide)Silanone: A Remarkable Room-Temperature-Persistent Silanone.

A silanone substituted by bulky amino and phosphonium bora-ylide substituents has been isolated in crystalline form. Thanks to the exceptionally strong electron-donating phosphonium bora-ylide substituent, the lifetime at room temperature of the silanone is dramatically extended (t =4 days) compared to the related (amino)(phosphonium ylide)silanone VI (t =5 h), allowing easier manipulation and its use as precursor of new valuable silicon compounds. The interaction of silanone with a weak Lewis acid such as MgBr increases further its stability (no degradation after 3 weeks at room temperature).

Mechanochemical Synthesis and Biological Evaluation of Novel Isoniazid Derivatives with Potent Antitubercular Activity.

A series of isoniazid derivatives bearing a phenolic or heteroaromatic coupled frame were obtained by mechanochemical means. Their pH stability and their structural (conformer/isomer) analysis were checked. The activity of prepared derivatives against cell growth was evaluated.

Exceptionally Strong Electron-Donating Ability of Bora-Ylide Substituent vis-à-vis Silylene and Silylium Ion.

Electropositive boron-based substituent (phosphonium bora-ylide) with an exceptionally strong π- and σ-electron donating character dramatically increases the stability of a new type of N-heterocyclic silylene 2 featuring amino- and bora-ylide-substituents. Moreover, the related silylium ion 4 and transition-metal-silylene complexes, with trigonal-planar geometries around the silicon center, are also well stabilized. Therefore, the N,B-heterocyclic silylene 2 can be used as a strongly electron-donating innocent ligand in coordination chemistry similarly to N-heterocyclic carbenes.

Fluorescent nanodiamond tracking reveals intraneuronal transport abnormalities induced by brain-disease-related genetic risk factors.

Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities.

Isotopic studies of metabolic systems by mass spectrometry: using Pascal's triangle to produce biological standards with fully controlled labeling patterns.

Mass spectrometry (MS) is widely used for isotopic studies of metabolism in which detailed information about biochemical processes is obtained from the analysis of isotope incorporation into metabolites. The biological value of such experiments is dependent on the accuracy of the isotopic measurements. Using MS, isotopologue distributions are measured from the quantitative analysis of isotopic clusters.

Sampling of intracellular metabolites for stationary and non-stationary (13)C metabolic flux analysis in Escherichia coli.

The analysis of metabolic intermediates is a rich source of isotopic information for (13)C metabolic flux analysis ((13)C-MFA) and extends the range of its applications. The sampling of labeled metabolic intermediates is particularly important to obtain reliable isotopic information. The assessment of the different sampling procedures commonly used to generate such data, therefore, is crucial.

Hydrolytic pathway of 5-fluorouracil in aqueous solutions for clinical use.

The purpose of the study was to investigate the degradation pathway of 5-fluorouracil (FU) in the situation of commercial formulations for clinical use, namely FU dissolved in sodium hydroxide (NaOH) solutions or Tris buffer at pH 8.5-9. Combination of data from (19)F, (1)H and (13)C NMR and in some cases MS led to the identification of 8 and 13 FU degradation products in NaOH and Tris solutions respectively.

A ¹H NMR study of the specificity of α-l-arabinofuranosidases on natural and unnatural substrates.

Background: The detailed characterization of arabinoxylan-active enzymes, such as double-substituted xylan arabinofuranosidase activity, is still a challenging topic. Ad hoc chromogenic substrates are useful tools and can reveal subtle differences in enzymatic behavior. In this study, enzyme selectivity on natural substrates has been compared with enzyme selectivity towards aryl-glycosides.

A novel platform for automated high-throughput fluxome profiling of metabolic variants.

Advances in metabolic engineering are enabling the creation of a large number of cell factories. However, high-throughput platforms do not yet exist for rapidly analyzing the metabolic network of the engineered cells. To fill the gap, we developed an integrated solution for fluxome profiling of large sets of biological systems and conditions.

[Unusual complication of noninvasive ventilation: The œsogastric pneumatosis associated with a subcutaneous emphysema].

The non-invasive ventilation (NIV) is a technique of ventilator support to avoid endotracheal intubation and its potential complications. However, it has some complications that are usually harmless to type of erythema and/or cutaneous ulcerations, mouth or nose dryness, conjunctival irritation and rarely lesions of barotrauma, volotrauma or gastric insufflation with nausea and vomiting. We report the case of a patient who had an unusual complication of NIV: sub mucosa gastro-esophageal pneumatosis associated with subcutaneous emphysema occurring on the second day after one hepatectomy which was settled but complicated with a postoperative pulmonary aspiration syndrome.

Fast spatially encoded 3D NMR strategies for (13)C-based metabolic flux analysis.

The measurement of site-specific (13)C enrichments in complex mixtures of (13)C-labeled metabolites is a powerful tool for metabolic flux analysis. One of the main methods to measure such enrichments is homonuclear (1)H 2D NMR. However, the major limitation of this technique is the acquisition time, which can amount to a few hours.

Limitation of diffusion effects in ultrafast 2D nuclear magnetic resonance by encapsulation of analytes in phospholipidic vesicles.

Increased sensitivity: A new sample-preparation procedure is described to limit molecular diffusion effects in NMR experiments. It is based on analyte encapsulation in liposomes and is particularly useful for ultrafast multidimensional NMR experiments.

A versatile and colorful screening tool for the identification of arabinofuranose-acting enzymes.

Selecting wall-nibblers: Three 4-nitrocatechol derivatives were designed to facilitate high-throughput screening of arabinofuranose hydrolases, enzymes that typically digest plant cell walls. The designed compounds can be used in solid and liquid media, and, importantly, one allows the specific detection of AXH-d, a specialized enzyme that only releases L-arabinose from disubstituted D-xylosyl moieties.

Photobioreactor design for isotopic non-stationary 13C-metabolic flux analysis (INST 13C-MFA) under photoautotrophic conditions.

Adaptive metabolic behavior of photoautotrophic microorganisms toward genetic and environmental perturbations can be interpreted in a quantitative depiction of carbon flow through a biochemical reaction network using isotopic non-stationary (13) C-metabolic flux analysis (INST (13) C-MFA). To evaluate (13) C-metabolic flux maps for Chlamydomonas reinhardtii, an original experimental framework was designed allowing rapid, reliable collection of high-quality isotopomer data against time. It involved (i) a short-time (13) C labeling injection device based on mixing control in a torus-shaped photobioreactor with plug-flow hydrodynamics allowing a sudden step-change in the (13) C proportion in the substrate feed and (ii) a rapid sampling procedure using an automatic fast filtration method coupled to a manual rapid liquid nitrogen quenching step.