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81.
The present paper is focused on the ability of aluminium phosphate (ALPC), magnesium ammonium phosphate (MGPC), magnesium hydrogen phosphate (MGHPC), and calcium hydrogenphosphate (CAHPC), adsorbed onto charcoal, to immobilise actinides by adsorption from natural waters. The objective of this process is to evaluate the environmental pollution due to the actinides. Europium, thorium, protactinium, neptunyl, and uranyl ions were chosen to simulate actinides in the +3, +4, +5 and +6 oxidation state. The adsorbers were tested using natural waters samples. The adsorption trends and capacities were analysed. ALPC and MGPC exhibited a similar behaviour and adsorbed demonstrating that the +5, +4 and +3 actinide ions can be easily immobilised from natural waters and may be successfully used at pH 7-8. MGHPC may be used at a higher pH, whereas CAHPC is effective in the whole pH range. In all cases, thorium, protactinium and europium were strongly 相似文献
82.
A. Bresson Y. Bidel P. Bouyer B. Leone E. Murphy P. Silvestrin 《Applied physics. B, Lasers and optics》2006,84(4):545-550
This paper is an introduction to the following articles in the scope of quantum mechanics for space study initiated by ESA and lead by ONERA. The context of quantum mechanics for space is summarised, and the fields under development are briefly introduced. Technological applications of quantum mechanics in space are explored and some tests of quantum mechanics are outlined. We also give a brief presentation of the opto-electronic section of the European Space Agency, and the technology development activities it carries out, with particular emphasis on those activities related to the topics of interest of the quantum mechanics in space workshop. As an example, a summary of two ESA studies on gravity gradiometry and their relevance to the field of atomic interferometry is given. In view of the scientific requirements, derived for both Earth observation and planetology for future space missions, atom interferometry shows promise and may provide an advantage over currently available accelerometer and inertial sensor systems. PACS 04.25.Nx; 04.80.Cc; 07.60.Ly; 95.30.Sf 相似文献
83.
Carlo Costa Antonella Bertazzo Graziella Allegri Silvia Catinella Pietro Traldi 《Journal of mass spectrometry : JMS》1991,26(11):972-976
The electron impact-induced fragmentation processes of pyrrole-2-, -3-, -2,3-, -3,4-, -2,5- and -2,3,4-carboxylic acids were investigated with the aid of metastable ion, collisional and deuterium labelling experiments. The general behaviour of these compounds is discussed in detail, together with the reasonable structures of the more relevant fragment ions. 相似文献
84.
Dalla Cort A Mandolini L Schiaffino L 《Chemical communications (Cambridge, England)》2005,(30):3867-3869
Whereas the parent uranyl salophen is catalytically inactive, its phenyl derivative effectively catalyses with turnover the reaction of benzoquinone with 1,3-cyclohexadiene, while showing no appreciable affinity towards reactants and product. 相似文献
85.
Multi-component, regio-selective aldol addition of β-ketoesters to aldehydes: scope and applications
More V Di Mola A Croce G Tedesco C Petronzi C Peduto A De Caprariis P Filosa R Massa A 《Organic & biomolecular chemistry》2011,9(24):8483-8488
Simple and effective multi-component one-pot aldol addition/protection reactions of β-ketoesters to a series of aldehydes in the presence Me(3)SiCl and i-Pr(2)EtN have been described. The analysis of the scope of the reaction revealed a dramatic dependence of the reactivity on the substrates used. Thus the effect of a catalytic amount of DMF and different reaction conditions was widely investigated. Further transformations of the aldol adducts were particularly useful to give valuable diols and compounds with quaternary stereocenters, while X-ray structural analysis gave also important stereochemical information about this challenging reaction. 相似文献
86.
Marotta E Lapolla A Fedele D Senesi A Reitano R Witt M Seraglia R Traldi P 《Journal of mass spectrometry : JMS》2003,38(2):196-205
The Maillard reaction occurring between sugars and amino groups is important in living systems. When amino groups belonging to protein chains are involved, the Maillard reaction has been invoked as responsible for protein cross-linking and the production of 'toxic' compounds. The reaction leads to the production of a heterogeneous group of substances, usually called advanced glycation end products (AGEs). Classical analytical approaches, such as spectroscopic (ultraviolet, fluorescence) and mass spectrometric (matrix-assisted laser desorption/ionization, liquid chromatography/electrospray ionization mass spectrometry) methods, have shown that the digestion mixture is highly complex. However, there are clear differences between the digestion mixtures of glycated and unglycated human serum albumin (HSA). In the former case, possible glycated peptides belonging to the AGE peptide class may be identified. Tandem mass spectrometric experiments on selected species seemed to be promising as regards structural information, but it was thought of interest to undertake the present investigation, based on liquid chromatography/electrospray ionization Fourier transform mass spectrometry, in order to obtain definitive results on their elemental composition. Using this approach, about 20 glycated peptides were detected and their possible structures were postulated by examining the known sequence of HSA. 相似文献
87.
In this paper we study a variable coefficient Sine-Gordon (vSG) equation given by theta(tt)-theta(xx)+F(x,t)sin theta=0 where F(x,t) is a real function. To establish if it may be integrable we have performed the standard test of Weiss, Tabor, and Carnevale (WTC). We have got that the (vSG) equation has the Painleve' property (Pp) if the function F(x,t) satisfies a well-defined nonlinear partial differential equation. We have found the general solution of this last equation and, consequently, the functions F(x,t) such that the (vSG) equation possesses the (Pp), are given by F(x,t)=F(1)(x+t)F(2)(x-t) where F(1)(x+t) and F(2)(x-t) are arbitrary functions. Using this last result we have obtained some particular solutions of the vSG equation. (c) 1995 American Institute of Physics. 相似文献
88.
Alunni S Del Giacco T De Maria P Fifi G Fontana A Ottavi L Tesei I 《The Journal of organic chemistry》2004,69(10):3276-3281
Catalysis of the beta-elimination reaction of N-[2-(4-pyridyl)ethyl]quinuclidinium (1) and N-[2-(2-pyridyl)ethyl]quinuclidinium (2) by Zn(2+) and Cd(2+) in OH(-)/H(2)O (pH = 5.20-6.35, 50 degrees C, and mu = 1 M KCl) has been studied. In the presence of Zn(2+), the elimination reactions of both isomers occur from the Zn(2+)-complexed substrates (C). The equilibrium constants for the dissociation of the Zn(2+)-complexes are as follows: K(d) = 0.012 +/- 0.003 M (isomer 1) and K(d) = 0.065 +/- 0.020 M (isomer 2). The value of k(C)(H2O) for isomer 1 is 4.81 x 10(-6) s(-1). For isomer 2 both the rate constants for the "water" and OH(-)-induced reaction of the Zn(2+)-complexed substrate could be measured, despite the low concentration of OH(-) in the investigated reaction mixture [k(C)H2O)= 1.97 x 10(-6) s(-1) and k(C)(OH-)= 21.9 M(-1) s(-1), respectively]. The measured metal activating factor (MetAF), i.e., the reactivity ratio between the complexed and the uncomplexed substrate, is 8.1 x 10(4) for the OH(-)-induced elimination of 2. This high MetAF can be compared with the corresponding proton activating factor (Alunni, S.; Conti, A.; Palmizio Errico, R. J. Chem. Soc., Perkin Trans. 2 2000, 453), PAF = 1.5 x 10(6) and is in agreement with an E1cb irreversible mechanism (A(xh)D(E)* + D(N)) (Guthrie, R. D.; Jencks, W. P. Acc. Chem. Res. 1989, 22, 343). A value of k(C)(H2O)>or= 23 x 10(-7) s(-1) is estimated for the Cd(2+)-complexed isomer 2, while catalysis by Cd(2+) has not been observed for isomer 1. 相似文献
89.
Antonella De Palma Antonella Roveri Mattia Zaccarin Louise Benazzi Simone Daminelli Giorgia Pantano Mauro Buttarello Fulvio Ursini Massimo Gion Pier Luigi Mauri 《Journal of chromatography. A》2010,1217(33):5328-5336
Since red blood cells (RBCs) lack nuclei and organelles, cell membrane is their main load-bearing component and, according to a dynamic interaction with the cytoskeleton compartment, plays a pivotal role in their functioning. Even if erythrocyte membranes are available in large quantities, the low abundance and the hydrophobic nature of cell membrane proteins complicate their purification and detection by conventional 2D gel-based proteomic approaches. So, in order to increase the efficiency of RBC membrane proteome identification, here we took advantage of a simple and reproducible membrane sub-fractionation method coupled to Multidimensional Protein Identification Technology (MudPIT). In addition, the adoption of a stringent RBC filtration strategy from the whole blood, permitted to remove exhaustively contaminants, such as platelets and white blood cells, and to identify a total of 275 proteins in the three RBC membrane fractions collected and analysed. Finally, by means of software for the elaboration of the great quantity of data obtained and programs for statistical analysis and protein classification, it was possible to determine the validity of the entire system workflow and to assign the proper sub-cellular localization and function for the greatest number of the identified proteins. 相似文献
90.
Kujawa P Moraille P Sanchez J Badia A Winnik FM 《Journal of the American Chemical Society》2005,127(25):9224-9234
The layer-by-layer growth of multilayer assemblies of two polysaccharides, the polyanion hyaluronan (HA) and the polycation chitosan (CH), was investigated using atomic force microscopy (AFM) and surface plasmon resonance (SPR) spectroscopy, with primary emphasis on the effect of the polysaccharide molecular weights on the film thickness and surface morphology. The HA/CH multilayers exhibit an exponential increase of the optical film thickness with the number of deposited bilayers. We show that the multilayer thickness at a given stage depends on the size of both CH, the diffusing polyelectrolyte, and HA, the non-diffusing species. Assemblies (12 bilayers) of high molecular weight polysaccharides (HA, 360,000; CH, 160,000) were twice as thick (approximately 900 nm vs approximately 450 nm) as those obtained with low molecular weight polymers (HA, 30,000; CH, 31,000), as assessed by AFM scratch tests. The exponential growth rate is the same for the high and low molecular weight pairs; the larger film thicknesses observed by SPR and by AFM arising from an earlier onset of the steep exponential growth phase in the case of the high molecular weight pair. In all cases, isolated islets form during the deposition of the first CH layer onto the underlying HA. Upon further film growth, individual islets coalesce into larger vermiculate features. The transition from distinct islands to vermiculate structures depends on the molecular weights of the polysaccharides and the lower molecular weight construct presents larger worm-like surface domains than the high molecular weight pair. 相似文献