À propos des exilés de Boukhara et de Kokand à Shahr-i Sabz

À la périphérie orientale de l’émirat de Boukhara se constitua autour de Shahr-i Sabz un petit État, qui resta pratiquement indépendant pendant la seconde moitié du XVIIIe et tout au long du XIXe siècle. Nous nous proposons ici d’illustrer une originalité de la petite principauté : l’asile offert par les souverains de Shahr-i Sabz et Kitâb aux Boukhariotes et Kokandiens en désaccord avec leurs souverains respectifs. En évoquant le sort de quatre personnages, nous voulons souligner les spécifi..

Local chain deformation and overstrain in reinforced elastomers: An NMR study

A molecular-level understanding of the strain response of elastomers is a key to connect microscopic dynamics to macroscopic properties. In this study we investigate the local strain response of vulcanized, natural rubber systems and the effect of nanometer-sized filler particles, which are known to lead to highly improved mechanical properties. A multiple-quantum NMR approach enables the separation of relatively low fractions of network defects and allows to quantitatively and selectively study the local deformation distribution in the strained networks matrix on the microscopic (molecular) scale. We find that the presence of nondeformable filler particles induces an enhanced local deformation of the matrix (commonly referred to as overstrain), a slightly increased local stress/strain heterogeneity, and a reduced anisotropy. Furthermore, a careful analysis of the small nonelastic defect fraction provides new evidence that previous NMR and scattering results of strained defect-rich elastomers cannot be interpreted without explicitly taking the nonelastic defect fraction into account

From Saussure to sociology and back to linguistics

The article highlights a semiotically relevant aspect of Niklas Luhmann’s Theory of Social Systems: its reception of the Saussurean dichotomies signifiant/signifié and langue/parole. Luhmann’s position is weighted against the Cours as well as Saussure’s original writings, sampling their approaches to form, meaning, the sign’s two-sidedness, and the relation of linguistic structure and speech events. Ultimately, the article proposes a social ontology of linguistic abstraction in line with general semiology that explains the motility of language through communication, thereby accounting for variability and optionality. It also indicates as to how the theoretical framework can feed into a model of linguistic description.Peer Reviewe

Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules