Efficient Removal of Volatile Organic Compounds by FAU-Type Zeolite Coatings.

Silicone and pure organic binders were used to develop FAU-type zeolite coatings applied on pre-treated aluminum substrates by using a spraying method and then cured under specific conditions. The influence of the amount of binder on adhesion properties of zeolite coatings was first investigated to determine the optimum ratio between zeolite and binder. Zeolite coatings were then elaborated with a high zeolite content (between 70 and 80 wt.%) to ensure high adsorption capacities. The amount of binders involved in different zeolite coatings was sufficient to achieve interesting adhesion and cohesion properties. The accessibility of zeolite microporosity was studied by nitrogen adsorption-desorption measurements, which revealed a very small or no loss of the micropore volume for the optimized coatings. Volatile Organic Compounds (VOCs) adsorption measurements were carried out using n-hexane as probe molecule. FAU-type zeolite in powder form adsorbs 180 mg/ganhydrous zeolite, whereas the amounts of n-hexane adsorbed by zeolite coatings ranged from 131 to 175 mg/ganhydrous zeolite.

Intrusion/Extrusion of water into organic grafted SBA-15 silica materials for energy storage.

Mesoporous SBA-15 silica materials were grafted with trialkylsilyl compounds having short (C1) and long (C8) carbon chain and characterized by XRD, N2 physisorption analysis, 29Si MAS-NMR and contact angle (CA) measurements. A drastic enhancement of the hydrophobic property after grafting was observed by forced intrusion water; it occurred in two steps and with quite high intrusion pressures (mean values - 10 and - 15 MPa). The hydrophobic nature of both internal and external surface area was confirmed by 29Si MAS-NMR and CA measurements, respectively. After contact with water, materials displayed a partial hydrophobic behaviour with uncompleted spontaneous extrusion. The energies absorbed during water intrusion correspond to 4.3 and 6.1 J x g(-1) for C1 and C8 grafted species, respectively.

Comparison of platelet count results on the Sysmex XN between citrate or MgSO4 and K2 EDTA anticoagulants.

INTRODUCTION: The aim of this study performed on Sysmex XN is to compare platelet values on citrate and MgSO4 (TBX) in patients with K2EDTA-induced platelet clusters and to identify platelet biases of these matrices compared to K2EDTA. METHODS: Sixty patients with K2EDTA-induced platelet clusters were re-sampled with K2EDTA, citrate and TBX. Platelet results were then compared, and smears were analysed for clumping. Platelet results from 120 patients without K2EDTA-induced platelet clusters were compared between K2 EDTA, citrate, and MgSO4 with impedance and fluorescence modes. Biases from regressions were analysed. RESULTS: Out of the 60 patients with K2EDTA-induced platelet clusters, none showed platelet clusters with MgSO4 whereas 50% still showed clusters with citrate. Among those without platelet clusters on citrate, the mean relative difference between (citrate- MgSO4 )/MgSO4 was -12.7% in impedance and -9.8% in fluorescence. Among the 120 patients without K2EDTA-induced platelet clusters, in fluorescence the mean relative bias with respect to K2EDTA was -2.06% for MgSO4 and -10.3% for Citrate. For the MgSO4 versus K2 EDTA regressions, the maximum absolute values of the 95% CI of the relative biases at 150 × 109 /L (5.45%) and 450 × 109 /L (3.56%) were below the desirable analytical objectives of the EFLM. CONCLUSION: In patients with K2EDTA-induced platelet clusters, MgSO4 is preferable to citrate. MgSO4 provides a bias with XN in fluorescence when compared to EDTA which is within analytical tolerance.

New insights in the formation of silanol defects in silicalite-1 by water intrusion under high pressure.

The "water-silicalite-1" system is known to act as a molecular spring. The successive intrusion-extrusion cycles of liquid water in small crystallites (6 × 3 × 0.5 µm(3)) of hydrophobic silicalite-1 were studied by volumetric and calorimetric techniques. The experiments displayed a decrease of the intrusion pressure between the first intrusion-extrusion cycle and the consecutive ones, whereas the extrusion pressures remained unchanged. However, neither XRD studies nor SEM observations revealed any structural and morphological modifications of silicalite-1 at the long-range order. Such a shift in the value of the intrusion pressure after the first water intrusion-extrusion cycle is attributed to the creation of silanol groups during the first water intrusion. Detailed FTIR and solid-state NMR spectroscopic characterizations provided a molecular evidence of chemical modification of zeolite framework with the formation of local silanol defects created by the breaking of siloxane bonds.

Platelet Counting: Ugly Traps and Good Advice. Proposals from the French-Speaking Cellular Hematology Group (GFHC).

Despite the ongoing development of automated hematology analyzers to optimize complete blood count results, platelet count still suffers from pre-analytical or analytical pitfalls, including EDTA-induced pseudothrombocytopenia. Although most of these interferences are widely known, laboratory practices remain highly heterogeneous. In order to harmonize and standardize cellular hematology practices, the French-speaking Cellular Hematology Group (GFHC) wants to focus on interferences that could affect the platelet count and to detail the verification steps with minimal recommendations, taking into account the different technologies employed nowadays. The conclusions of the GFHC presented here met with a "strong professional agreement" and are explained with their rationale to define the course of actions, in case thrombocytopenia or thrombocytosis is detected. They are proposed as minimum recommendations to be used by each specialist in laboratory medicine who remains free to use more restrictive guidelines based on the patient's condition.

Pure silica chabazite molecular spring: a structural study on water intrusion-extrusion processes.

Water intrusion-extrusion isotherms performed at room temperature on hydrophobic pure silica chabazite show that the water-Si-CHA system displays real spring behavior. However, differences in pressure-volume diagrams are observed between the first and the other intrusion-extrusion cycles, indicating that some water molecules interact with the inorganic framework after the first intrusion. (29)Si and especially (1)H solid-state NMR showed the creation of new defect sites upon the intrusion-extrusion of water and the existence of two kinds of water molecules trapped in the supercage of Si-CHA: a first layer of water strongly hydrogen bonded with the silanols of the framework and a subsequent layer of liquidlike physisorbed water molecules undergoing interaction with the first layer. This hydrogen bonding scheme is also supported by X-ray powder diffraction.

Evaluation of the analytical performances of the Cobas c513 analyser for HbA1c assay.

INTRODUCTION: Haemoglobin A1c (HbA1c) is considered to be the gold standard for the follow-up of glycaemic control in patients with diabetes mellitus and is also a diagnostic tool. Accordingly, reliable and efficient methods must be used for its quantification. Roche Diagnostics have recently adapted the Tina-quant® HbA1c Third Generation immunoassay on a fully dedicated analyser, the Cobas c513, which allows a high throughput of up to 400 samples per hour. The present article deals with the evaluation of the analytical performances of this system which has been recently introduced to the market. MATERIALS AND METHODS: Precision, comparison with two ion-exchange high-performance liquid chromatography (HPLC) methods (Variant II and D-100 systems, BioRad Laboratories) using Passing Bablok and Bland-Altman analyses, accuracy and interference of the most frequent haemoglobin (Hb) variants on HbA1c measurement were evaluated. RESULTS: Precision was high, with coefficients of variation lower than 1.1% (HbA1c values expressed in National Glycohemoglobin Standardization Program units, 1.7% for values expressed in International Federation of Clinical Chemistry and Laboratory Medicine [IFCC] units). The comparison study showed similar results with the two HPLC systems. The analysis of samples with IFCC-assigned values showed high methodological accuracy. Finally, no interference of bilirubin, triglycerides and common Hb variants (Hb AC, AD, AE, AS) was observed. CONCLUSIONS: This evaluation showed that the analytical performance of the Cobas c513 analyser for HbA1c assay makes it suitable for a routine use in clinical chemistry laboratories.

Synthesis, Structure Analysis, and Characterization of a New Thiostannate, (C(12)H(25)NH(3))(4)[Sn(2)S(6)].2H(2)O.

A new thiostannate, (C(12)H(25)NH(3))(4)[Sn(2)S(6)].2H(2)O, was synthesized from SnCl(4), Na(2)S, and dodecylamine (DDA) in the ethanol-water two-solvent system at room temperature. First a suspension was obtained. With increasing crystallization time, single crystals up to several millimeters in size were found at the bottom of the vessel. The compound was characterized by single-crystal X-ray diffraction, solid state (119)Sn CPMAS NMR and (13)C CPMAS NMR, IR absorption spectroscopy, and thermal analysis. The crystal data are a = 7.533(2) Å, b = 10.162(2) Å, c = 21.688(4) Å, alpha = 101.22(3) degrees, beta = 90.76(3) degrees, gamma = 101.82(3) degrees, triclinic, space group = P&onemacr;, and Z = 1. The structure consists of one [Sn(2)S(6)](4)(-) anion, four n-dodecylammonium cations, and two water molecules per unit cell. The [Sn(2)S(6)](4)(-) dimers are formed by two edge-sharing [SnS(4)] tetrahedra. The hydrocarbon chains of the cations are straight with the chain direction running parallel to [001]. The chains are in van der Waals contact to each other with the nitrogen atoms pointing in opposite directions for neighboring chains. The positions of all hydrogen atoms were determined; in particular three positions were found which may suggest that the nitrogen atoms are protonated to form cationic groups. The nonorganic constituents of the structure, i.e., anions, water molecules, and ammonium groups, interact to form an infinite layer-like unit parallel to (001).

Analysis of two bentonites of enological interest before and after commercial activation by solid Na(2)CO(3).

Two natural calcium-rich bentonites used for the removal of wine proteins, originating from Greece and Turkey, were studied by X-ray diffraction, thermal analysis, and solid state NMR, before and after activation by solid Na(2)CO(3). Exchange of Ca(2+) by Na(+) mainly occurs for cations located at the edge of layers and only weakly for interlayer cations. This Na(2)CO(3) activation process leads to an increased efficiency in the adsorption process of bovine serum albumin (BSA) used as a model protein for both bentonites. A direct correlation is observed between the extent of Ca(2+)/Na(+) exchange, the strength of adsorption of BSA, and the extent of unfolding of BSA backbone.

Syntheses of zeolite beta films in fluoride media and investigation of their sorption properties.

Zeolite beta films were synthesized on glass slides and silicon wafers using the secondary growth method. The hydrothermal synthesis was performed in fluoride media with a wide variation of synthesis parameters. The kinetics of crystal growth under different conditions was studied, and film thicknesses ranging between 0.7 and 40 microm were obtained. A synthesis at 160 degrees C for 9 days was found to be the best compromise between the duration and the temperature of crystallization, providing films with thickness of 40 microm. Grazing incidence X-ray diffraction (GID) combined with scanning electron microscopy (SEM) analysis revealed the formation of highly crystalline, randomly oriented films. Sorption capacities and kinetics of the films and corresponding powders were studied toward several organic adsorbents (cyclohexane, n-hexane, p-xylene, trimethylbenzene, tetramethoxysilane). It was found that the adsorbed quantity depends both on the kinetic diameter and on the shape of the molecule, while the sorption capacity of the zeolitic films was estimated to be 7.14 mmol g(-1) of zeolite by nitrogen sorption tests. Kinetics data showed that the adsorption was faster on zeolite powders compared to corresponding films, revealing the presence of additional diffusion barriers in the intergrown layers.

Thermodynamics of water intrusion in nanoporous hydrophobic solids.

We report a joint experimental and molecular simulation study of water intrusion in silicalite-1 and ferrerite zeolites. The main conclusion of this study is that water condensation takes place through a genuine first-order phase transition, provided that the interconnected pores structure is 3-dimensional. In the extreme confinement situation (ferrierite zeolite), condensation takes place through a continuous transition, which is explained by a shift of both the first-order transition line and the critical point with increasing confinement. The present findings are at odds with the common belief that conventional phase transitions cannot take place in microporous solids such as zeolites. The most important features of the intrusion/extrusion process can be understood in terms of equilibrium thermodynamics considerations. We believe that these findings are very general for hydrophobic solids, i.e. for both nonwetting as well as wetting water-solid interface systems.

Autoimmune antibodies to hnRNPG protein in dogs with systemic lupus erythematosus: epitope mapping of the antigen.

We previously reported the presence of circulating autoantibodies to hnRNPG protein in dogs with systemic lupus erythematosus (Soulard et al. 1993, 1994). These antibodies appeared to be specifically limited to German shepherd dog species. In the present report, we have analysed the nature of the hnRNPG epitopes responsible for autoantibody specificity. By using a set of 11 dog sera selected for their strong reactivity to hnRNPG protein, we have found that these sera had the ability to recognize two epitopes: (1) within a stretch of 33 amino acids located around the central part of protein, that is readily detected by immunoblotting; (2) a N-terminal conformation of the protein close to the RNA binding domain (RBD), that is revealed by immunoprecipitation. Our data strongly support the notion that the dog autoimmune response against hnRNPG protein is antigen-driven.