Immunodetection by quartz crystal microbalance

Biodetection is one of the most important challenges for the twenty-first century: many fields are concerned, mainly environmental and medical. The quartz crystal microbalance (QCM) may offer great possibilities for this purpose: a direct response signal, which characterizes the binding event between a sensitive layer, immobilized onto the surface transducer, and the analyte to be detected, can be obtained. However, for the detection of small biomolecules such as antigens, it is quite difficult to obtain an observable signal that corresponds directly to the binding event. In general, this is owing to the lack of mass sensitivity of the commonly used QCM, with 5- to 10-MHz quartz crystals. For improving this mass sensitivity, a 27-MHz quartz resonator was developed and incorporated in a flow-through microcell. Two biospecies, IgG rabbit and peroxidase enzyme, were studied with this ultra-sensitive QCM in terms of specificity, detection limit, and calibration curve.     

Assessment of the Fe-Sn-Zn phase diagram at 450°C

The Fe-Sn-Zn system is of interest because Sn is one element added to the Zn galvanizing bath to overcome the drawbacks due to the presence of Si in semi-killed steels. This work has been undertaken with the aim to understand the tin effect on the microstructure and the layers growth in batch galvanized coatings on low alloyed steels. Various experimental techniques such as metallography, scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDX) are used in order to characterize the microstructure and the properties of such coatings elaborated in a zinc bath enriched with tin. Solidification phenomena and layers growth mechanisms during galvanization are explained by means of the ternary phase diagram Fe-Sn-Zn at 450°C. The Calphad method allows to obtain this phase diagram from the three optimized binary phase diagrams Fe-Sn, Fe-Zn and Sn-Zn and some experimental data inside the ternary Fe-Sn-Zn system.     

Micro-enzyme field effect transistor sensor using direct covalent bonding of urease

Enzyme field effect transistors (ENFETs), which have been previously proposed for the detection of urea, consist of a pH ion-sensitive FET with urease enzyme immobilized in a polymeric membrane. A new means of preparing the enzymatic sensing layer is proposed in which urease is directly covalently bonded onto the silica insulator. The sensitivity, lifetime and response time of the ENFETs obtained are fairly good.     

Characterization of low-molecular weight peptides in champagne wine by liquid chromatography/tandem mass spectrometry

This paper reports the use of an on-line LC–ESI–MS/MS method for the identification and quantification of di- and tripeptides in champagne wine without laborious sample pretreatment. The identification of these compounds, in their underivatised form, is based on identical retention times and ESI–MS spectra to those of reference standards. The presence of nine dipeptides (Arg–Ile, Ile–Arg, Ile–Val, Lys–Phe, Lys–Tyr, Phe–Lys, Tyr–Gln, Tyr–Lys, Val–Ile) and the absence of two tripeptides (Phe–Arg–Arg and Lys–Met–Asn) have been evidenced in the matrix. Calibration curves for each analyte were established using Phe–Arg as internal standard. The calibration curves were linear in the concentration range 0.1–10 mg L⁻¹ with a determination coefficient, r², better than 0.992. The accuracy for the calibration standard was estimated at between 92 and 102%. This method allows high recovery and satisfies the necessary requirements with respect to accuracy, repeatability and sensitivity. The first application of this analytical method to the measurement of di- and tri-peptides in different vintages of champagne wine is reported. Compositional changes in the peptides occurred depending on the vintage.     

C∞ functions in infinite dimension and linear partial differential difference equations with constant coefficients

This work is closed to [2] where a dense linear subspace \(\mathbb{E}\) (E) of the space ?(E) of the Silva C ^∞ functions on E is defined; the dual of \(\mathbb{E}\) (E) is described via the Fourier transform by a Paley-Wiener-Schwartz theorem which is formulated exactly in the same way as in the finite dimensional case. Here we prove existence and approximation result for solutions of linear partial differential difference equations in \(\mathbb{E}\) (E) with constant coefficients. We also obtain a Hahn-Banach type extension theorem for some C^∞ functions defined on a closed subspace of a DFN space, which is analogous to a Boland’s result in the holomorphic case [1].     

Préparation de quelques 4-nitroisoxazoles à partir de pseudonitrosites de cétones éthyléniques du type chalcone

The Synthesis of some 4-Nitroisoxazoles from Pseudonitrosites of Chalcones The action of dinitrogen trioxide with α,β-unsaturated ketones of the chalcone type leads to pseudonitrosites (Table 1) which are cyclized to 4-nitro-3,5-diarylisoxazoles (Table 2).     

Action du chlorure de nitrosyle sur le trichloréthylène et sur le tétrachloréthylène

Nitrosyl chloride is only chlorinating in darkness and above 100°. In the sun light and at room temperature it reacts as a chlorinating, nitrosating, nitrating and oxidizing agent. With trichlorethylene in fact pentachlorethane 1,1,1,2-tetrachloro-2-nitrosoethane, 1,1,1,2-tetrachloro-2-nitroethane, dichloracetic acid and a compound of empirical formula C₄H₂Cl₅NO₂ are obtained. Tetrachloroethylene carried to hexachlorethane, pentachloronitrosoethane and tetrachloro-2-(pentachlorethyl)-1,2-oxazetidine. Introduced nitrosyl chloride provided nitrogen monoxide prouved by gaz chromatography. This monoxide reacted afterwards to give nitrogen which is the single nitrogenous gazeous compound. Carbondioxide is a minor component of the gaz.