Identification of animal glue species in artworks using proteomics: application to a 18th century gilt sample

This study proposes a proteomic-based strategy for the identification of the origin species of glues used as binding media and adhesives in artworks. The methodology, based on FTICR high resolution mass spectrometry, was evaluated on glues from different animal origin (i.e., bovine, rabbit, and fish). The analysis of the peptide mixture resulting from the enzymatic hydrolysis of the proteins led to the identification of species-specific peptides. Up to 15 specific peptides were identified for the bovine species and three for the rabbit species and, in the case of sturgeon glue, three fish-specific peptides were found by sequence homology to the rainbow trout. Then, the method was applied to authenticate different rabbit skin glue samples, including a 100 year-old sample named "Colle à Doreurs" coming from the "Maison Totin-Frères". For this sample, two specific peptides of rabbit collagen were identified. To evaluate the method in a complex matrix, model paints composed of lead white, linseed oil, and animal glue were prepared. Species-specific peptides were identified in each paint sample. Finally, a gilt sample from St Maximin church dating from the eighteenth century was analyzed, and 13 peptides specific to bovine collagens were identified starting from very low sample amount (50 μg).     

Rod-like oligomers incorporating 2,6-dialkylamino core-substituted naphthalene diimide as acceptors for organic photovoltaic

Core-substituted naphthalene diimides (core-substituted NDIs) were incorporated into rod-like molecules and oligomers through reaction at the imide nitrogen positions. N,N′-Di(4-bromophenyl)-2,6-di(N-alkylamino)-1,4,5,8-naphthalenetetracarboxydiimide was synthesized in only three steps, and used as a versatile platform to prepare extended structures by reaction with thiophene substrates using Suzuki-coupling conditions. The optoelectronic properties of the new compounds were examined by UV/vis absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry and theoretical calculations. The imide substituents had little effect on the optical and electrochemical properties of core-substituted NDIs in solution. A bathochromic shift of the absorption was observed upon film formation, accompanied by quenching of fluorescence. These observations are consistent with increased inter-molecular interactions between core-substituted NDI moieties in the solid state. All compounds were tested in organic solar cells by blending with poly(3-hexylthiophene), and several showed a photovoltaic effect, demonstrating their potential as electron acceptors in organic solar cell. The best solar cell was observed for core-substituted NDI with 4-(thiophen-2-yl)phenyl imide substituents (5a), showing a power conversion efficiency of 0.57% and a large open circuit voltage of 0.87 V. This approach allows new structure–property relationship studies of non-fullerene acceptors in organic solar cells, where one can vary the imide substituent to optimize photovoltaic parameters while keeping the optical and electrochemical properties constant.     

Investigation of a new structural type for Y2WO6

A new phase for the rare earth tungstate Y₂WO₆ was synthetized at high temperature. The parameters of the orthorhombic unit cell determined on small single crystals are $\text{a}\text{= 8.591}\text{A}\text{?}$, $\text{b}\text{= 20.84}\text{A}\text{?}$, $\text{c}\text{= 5.233}\text{A}\text{?}$ and the space group is probably P212121.The fluorescence spectrum of the 2% Europium doped compound reveals the existence of four crystallographic sites for Yttrium, which is consistent with the X-Ray data.     

Étude de L’estimation d’une Fonction Aléatoire Gaussienne a Une Date Repérée par Rapport a un Passage par un Extremum du Processus — Application a la Prédiction

Annals of Telecommunications - Les auteurs s’intéressent à la densité de probabilité de la variable aléatoire: amplitude d’un processus gaussien stationnaire...     

Factors affecting the moisture permeability of lipid-based edible films: a review

Moisture transfers inside food products could be controlled or limited by the use of edible films. These are usually based on hydrophobic substances such as lipids to improve barrier efficiency. Water permeability of films is affected by many factors, depending on both the nature of barrier components, the film structure (homogeneous, emulsion, multilayer, etc.), crystal type, shape, size and distribution of lipids, and thermodynamics such as temperature, vapor pressure, or the physical state of water in contact to the films. After a brief presentation of lipids and hydrophobic substances used as moisture barrier, cited in the scientific literature, this article reviews all of the parameters affecting barrier performances of edible films and coatings.     

Preparation,stabilite et etude cristallographique preliminaire du compose Bi2Sn2O7

Our crystallochemistry investigation of the Bi₂O₃ - SnO₂ binary in the range of compositions between 60 and 75 SnO₂ moles percent, brings new evidence of the compound Bi₂Sn₂O₇. It has a tetragonal structure ($\text{a}\text{= 21.31}\text{A}\text{?}$, $\text{c}\text{= 21.53}\text{A}\text{?}$), related to the pyrochlore structure.From this study arises a new problem about the influence of Bi3+ ion on the doubling of the crystalline parameters.     

Two‐dimensional gel electrophoresis of apolipoprotein C‐III and other serum glycoproteins for the combined screening of human congenital disorders of O‐ and N‐glycosylation

Congenital disorders of glycosylation (CDG) are inherited diseases that can affect not only the N‐glycan (e.g. CDG type I and II) but also the O‐glycan biosynthesis pathway. In the absence of specific clinical symptoms, there is a need for a reliable biological screening of these two groups of CDG. Using a few microlitres of human serum, 2‐DE and immunoblotting were applied to the separation and simultaneous detection of the isoforms of the O‐glycosylated protein apolipoprotein C‐III (apoC‐III) and of four N‐glycosylated proteins, namely alpha‐antitrypsin, alpha‐1 acid glycoprotein, haptoglobin and transferrin. For the study of O‐glycosylation, this technique allowed the reliable separation of the three fractions of apoC‐III and the determination of normal percentage values in an adult population. Concerning N‐glycosylation, the study of serum samples from patients with CDG type Ia revealed marked abnormalities systematically affecting the four 2‐DE separated N‐linked glycoproteins. 2‐DE coupled to immunoblotting using a mixture of specific antibodies could be easily and reliably employed for the combined screening of both N‐ and O‐glycosylation disorders in humans.     

Parasitic diffuse reflection in a Fourier transform spectrometer yielding subharmonic ghosts and line-shape distortion

When using a high-resolution Fourier transform spectrometer (FTS) in a cube-corner configuration, subharmonic ghosts are observed in the spectrum. These ghosts are attributable to parasitic diffuse reflections on the mirrors of the FTS arm. The reflected beams skip a part of the interferometer and travel a different path from the main beam thus experiencing a smaller optomechanical gain. These reflections are present in the reference laser channel as well as on the measurement channel, and each affect the estimated spectrum differently. The sampling grid generated by the reference laser has periodic errors that are synchronized with the fringe signal. The measured spectrum can therefore exhibit sampling jitter ghosts at submultiples of the reference laser wavenumber in addition to its own additive subharmonics. The diffuse reflection experiencing the nominal optomechanical gain, such as in a plane-mirror configuration, will impact directly on the instrument line shape and on the radiometric accuracy of the spectrometer since some radiation is not propagating at the expected angles in the instrument.     

Additional evidence for intact appetitive trace conditioning in hippocampal-lesioned rats.

Hippocampal lesions impair aversive trace conditioning but do not interfere with appetitive Pavlovian trace conditioning of the licking response (LR). This experiment examined whether learning to discriminate the events occurring in the home cage and in the training chamber could account for the differential effects of hippocampal lesions on aversive and appetitive trace conditioning. Performance of rats with excitotoxic lesions of the hippocampus was compared to that of sham-operated rats in LR trace conditioning. The unconditional stimulus (US) “cola soft drink” was delivered only in the training chamber. Thus, as in aversive conditioning procedures, the hedonic properties of the US and the resulting behaviors and motivational states occurred only in that environment. The results failed to reveal learning differences between lesioned rats and controls. Our findings and those of other reports concur that trace conditioning with an appetitive US is independent of the hippocampal system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)