Metabolic compartmentalization in the human cortex and hippocampus: evidence for a cell- and region-specific localization of lactate dehydrogenase 5 and pyruvate dehydrogenase

Background  

For a long time now, glucose has been thought to be the main, if not the sole substrate for brain energy metabolism. Recent data nevertheless suggest that other molecules, such as monocarboxylates (lactate and pyruvate mainly) could be suitable substrates. Although monocarboxylates poorly cross the blood brain barrier (BBB), such substrates could replace glucose if produced locally.     

Computational insights about the dynamic behavior for the inclusion process of deprotonated and neutral aspirin in β-cyclodextrin

A high-efficiency microwave irradiation (MW) assisted protocol was proposed to synthesize series SPE-β-CD with specific degree of substitution (DS) in the sodium hydroxide solution. This protocol provided an eco-friendly way to modify the cyclodextrins with bulky sulfopropyl substituent on the purpose of avoiding organic solvents and high quantities of thermal energy. Temperature and energy distribution became more uniform under the new method accordingly. Therefore, not only the reaction time reduced significantly from over 20 h to a few hours, but also the DS increased up according to ¹H NMR spectroscopy, MS and elemental analysis results. Most importantly, the effects of reaction parameters on DS were compared both under MW method and conventional heating method, and were sufficiently studied to guarantee the aforementioned results could be better reproduced and DS of products could become more specific through the synthesis process. Products structures were characterized by FT-IR, DSC, and ¹³C NMR spectroscopy.     

REACTION DES O,O-DIETHYL OXO-1 ALKANEPHOSPHONATES AVEC LES DERIVES DE L'HYDRAZINE: UNE VOIE DE SYNTHESE DES HYDRAZONES α-PHOSPHONATEES ET DES HYDRAZIDES

Abstract

Under the normal conditions, the reaction of hydrazine and methylhydrazine with OO-diethyl 1 oxoalkane phosphonates 1 proceeds by cleavage of the phosphorus-carbon bond and leads to the formation of diethylphosphite 2 and N-acylhydrazide 3 . A procedure has been developed for the synthesis of new primary hydrazone of OO-diethyl 1-oxoalkane phosphonates 4 . A mechanism is proposed. The structure of those compounds 4 was confirmed by NMR and IR spectroscopy.     

Hydrolysis-Condensation Kinetics of Different Silane Coupling Agents

Abstract

The hydrolysis kinetics of 14 alkoxy silane coupling agents were carried out in an ethanol:water 80:20 (w/w) solution under acidic conditions and were monitored by ¹H, ¹³C, and ²⁹Si NMR spectroscopy. Acidic conditions were selected in order to enhance the silanol formation and to slow down the self-condensation between the resulting hydrolysed silanol groups. In situ ²⁹Si NMR spectroscopy allowed the determination of the intermediate species as a function of the reaction time. Thus, the following silane coupling agents were studied: 3-methacryloxypropyl trimethoxy silane (MPMS), 3-mercaptopropyl trimethoxy silane (MRPMS), 3-cyanopropyl triethoxy silane (CPES), triethoxy vinyl silane (VES), trimethoxy (2-phenylethyl) silane (PEMS), octyl triethoxy silane (OES), trimethoxy (7-octen-1-yl) silane (OEMS), 3-aminopropyl triethoxy silane (APES), 3-aminopropyl trimethoxy silane (APMS), 3-(2-aminoethylamino)propyl trimethoxy silane, (DAMS), 3-[2-(2-aminoethylamino)-ethylamino]propyl trimethoxy silane (TAMS), 4-amino-3,3-dibutyl trimethoxy silane (ADBMS), trimethoxy [3-(phenylamino)propyl] silane (PAPMS), and triethoxy-3-(2-imidazolin-1-yl) propyl silane (IZPES). A parameter quantifying the grafting potentiality of each silane coupling agent towards OH-rich solid substrates (such as cellulose) was established as a function of the nature of the alkoxy groups (methoxy or ethoxy), as well as that of the fourth substituent (vinyl, aminopropyl, etc.) of the silane studied.

GRAPHICAL ABSTRACT     

Fixed-bed column studies of pentachlorophenol removal by use of alginate-encapsulated pillared clay microbeads

The high rate of electron/hole pair recombination reduces the quantum yield of the processes with TiO(2) and represents its major drawback. Adding a co-adsorbent increases the photocatalytic efficiency of TiO(2). In order to hybridize the photocatalytic activity of TiO(2) with the adsorptivity of carbon nanotube, a composite of multi-walled carbon nanotubes and titanium dioxide (MWCNT/TiO(2)) has been synthesized. The composite was characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared absorption spectroscopy (FTIR), and diffuse reflectance UV-vis spectroscopy. The catalytic activity of this composite material was investigated by application of the composite for the degradation of methyl orange. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO(2). The enhancement in photocatalytic performance of the MWCNT/TiO(2) composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNT acts as a dispersing agent preventing TiO(2) from agglomerating activity during the catalytic process, providing a high catalytically active surface area. This work adds to the global discussion of how CNTs can enhance the efficiency of catalysts.     

Surface characterization of cellulose fibres by XPS and inverse gas chromatography

Inverse gas chromatography (IGC) was used to determine the dispersive component of the free energy as well as the acid-base properties of cellulose fibre surfaces, before and after modification by corona treatment. It was found that the corona treatment increases both the dispersive contribution to surface energy and its acidic character, whereas only a slight increase in its basicity was observed. It was also found that some chemical degradation of the surface occurs at high corona currents. The extent of modification of the surface properties, as revealed by IGC, was correlated to the surface chemical composition deduced from XPS analysis as well as with the electrical conductance and the pH of the water suspensions of the cellulose fibres.     

Synthese De (1,2a)Benzimidazolo-1,3,5,2-triazaphosphorine-2-oxides

The reaction of hexamethylphosphotriamide or methylphosphonic bis(dimethylamide) compounds with amidines derived from N-Benzimidazoyl imidates 1 leads to (1,2a)benzimidazolo-1,3,5,2-tiazaphosphorine-2-oxides 4 in good yields. If the condensation is realized at room temperature, N-phosphonic amidines 3 can be isolated as intermediates. The isolated compounds 2 , 3 , and 4 are identified by spectroscopic methods: IR, 1 H, 13 C, 31 P, NMR, and M.S.     

Ageing of wet-synthesized oxide powders

Wet chemical synthesis of precursor oxide ceramics is a method to obtain small particulate powders. Such powders are far more prone to ageing in air than more traditional precursors. Thermogravimetric analysis is used to highlight the species responsible for the ageing of ceramic precursors. Indeed water and carbon dioxide are observed to evolve from aged powders. Ceramics obtained from aged precursors can reach a very low final density with respect to the theoretical value. A large degree of the original sintering properties can be recovered after washing the aged powders with ethanol in a basic medium.