Glycoside nucleoside lipids (GNLs): An intrusion into the glycolipids’ world?

Glycoside nucleoside lipids (GNLs) are a new class of low-molecular-weight amphiphilic molecules capable of gelling either aqueous or organic solvents. This article provides an overview of some related lipid conjugate properties and the origin of the GNLs’ discovery. Finally, recent biological results obtained with two different GNLs demonstrate the great variety of applications they may offer, and how they can find their place in the large glycolipids’ community.     

Experimental study of the gas phase chemistry of C3H3+ with several cyclic molecules

Rate coefficients and ion product distributions have been determined for the gas phase reactions of C₃H₃⁺ with several homocyclic and heterocyclic molecules in a selected ion flow tube (SIFT) at 298 K. The rate coefficients for both the linear and cyclic isomers of C₃H₃⁺ are given. l-C₃H₃⁺ reacts by association in the majority of the reactions. c-C₃H₃⁺ is shown to be more reactive than previously suggested by low pressure experiments. In fact, the cyclic isomer reacts at the gas kinetic rate when the reaction involves a nitrogen containing cyclic compound but is less reactive with oxygen containing cyclic compounds. It is noted this reactivity of both the cyclic and linear isomer should be included when modeling the atmosphere of Titan due to the large number of nitrogen containing molecules that are considered to be present. Currently, the models consider electron recombination to be the only loss channel for c-C₃H₃⁺.     

Efficient sonochemical synthesis of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides

An ultrasound-assisted preparation of a series of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides that proceeds via the efficient reaction of chalcones with aminoguanidine hydrochloride under clean conditions is described.     

Palladium and platinum sorption using chitosan-based hydrogels

Two chitosan hydrogels (prepared by NaOH neutralization and by polyphosphate ionotropic gelation) have been tested in the dry state for Pd(II) and Pt(IV) sorption at pH 2. Similar sorption isotherms with maximum sorption capacities close to 190 mg Pd g⁻¹ and 235 mg Pt g⁻¹ were achieved. The sorption mechanism involves electrostatic attraction of the chloro-anionic species onto protonated amine groups; the drastic decrease of sorption capacity with the addition of chloride ions supports this hypothesis. SEM-EDAX analysis suggests that sorption proceeds, in kinetic terms, through a shrinking core mechanism. Metal ions can diffuse throughout all the sorbent volume. The main differences between the sorbents are revealed by kinetics. The hydrogels prepared by ionotropic gelation in polyphosphate (C-PPh) allows reaching equilibrium much faster than the hydrogels prepared by the neutralization process (C-NaOH). While for C-PPh sorbent the chemical reaction rate seems to control sorption profiles, in the case of C-NaOH a combination of mechanisms including intraparticle diffusion resistance controls uptake kinetics. Metal desorption from loaded sorbents is possible using thiourea alone or in association with HCl solutions. The recycling of the sorbents is possible but for a limited number of cycles.     

Ultrasound-assisted synthesis of aliphatic acid esters at room temperature

This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.     

The proteome of lentil (Lens culinaris Medik.) seeds: Discriminating between landraces

Lentil (Lens culinaris Medik.) is one of the most ancient crops of the Mediterranean region used for human nutrition; an extensive differentiation of L. culinaris over millennia has resulted in a number of different landraces. As a consequence of environmental and socio‐economic issues, the disappearance of many of them occurred in more recent times. To investigate the potential of proteomics as a tool in phylogenetic studies, testing the possibility to identify specific markers of different plant landraces, 2‐D gel electrophoretic maps of mature seeds were obtained from seven lentil populations belonging to a local ecotype (Capracotta) and five commercial varieties (Turca Rossa, Canadese, Castelluccio di Norcia, Rascino and Colfiorito). 2‐DE analysis resolved hundreds of protein species in each lentil sample, among which only 122 were further identified by MALDI‐TOF PMF and/or nanoLC‐ESI‐LIT‐MS/MS, probably as a result of the poor information available on L. culinaris genome. A comparison of these maps revealed that 103 protein spots were differentially expressed within and between populations. The multivariate statistical analyses carried out on these variably expressed spots showed that 24 protein species were essential for population discrimination, thus determining their proposition as landrace markers. Besides providing the first reference map of mature lentil seeds, our data confirm previous studies based on morphological/genetic observations and further support the valuable use of proteomic techniques as phylogenetic tool in plant studies.     

Electrochemical method for sulphur dioxide removal from flue gases: Application on sulphuric acid plant in Tunisia

This article presents an electrochemical method for sulphur dioxide removal; the idea consists to couple the phenomenon of electrolysis upstream to the sulphuric acid plant. Otherwise, this proposition consists in modifying the hybrid cycle Westinghouse by the elimination of the sulphuric acid decomposition stage, which corresponds to 61% of the energy distribution of this cycle. The step of the decomposition is replaced by the exploitation of the quantity of sulphur dioxide emissions SO₂ stemming from the process of sulphuric acid H₂SO₄ production. The industrial complex of Gabès in South Tunisia is selected to be the case study complex. In fact, most industries are chemical oriented, the fast growing numbers of H₂SO₄ factories have resulted in fairly serious air pollution, especially sulphur dioxide SO₂ pollution. To confirm the efficiency of this process, a mass balance study was made on the sulphuric acid plant, which used a double contact/double absorption process; this study demonstrates that this new method can treat 8 t d^?1 of sulphur dioxide, recover 12 t d^?1 of sulphuric acid of title 50% and produce 6889 m³ d^?1 of the hydrogen. This idea can achieve economical and environmental benefits. It is concluded that the usage of this electrochemical process can significantly reduce the SO₂ air pollution in Gabès (South Tunisia) by the elimination of 46.94 t d^?1 of SO₂. The results obtained are ambitious for future application of the new process, which can succeed in the realisation of 3.92 million dollars of gain every day.