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31.
Grant F. Armstrong Grant Cairns Barry Jessup 《Proceedings of the American Mathematical Society》1997,125(2):381-385
Betti numbers for the Heisenberg Lie algebras were calculated by Santharoubane in his 1983 paper. However few other examples have appeared in the literature. In this note we give the Betti numbers for a family of -dimensional 2-step nilpotent extensions of by .
32.
Bhattacharyya S Salvetat JP Roy D Heresanu V Launois P Saboungi ML 《Chemical communications (Cambridge, England)》2007,(41):4248-4250
Highly ordered self-assembled multi-layer structures with denatured collagen wrapped single wall carbon nanotubes and surfactant systems were obtained through bioinspired methodology. 相似文献
33.
Inks and paper are the main materials and components of library and archive collections. Since the beginning of paper and ink production empirical recipes have been followed, but in the 19th century with the transformation of Europe during the Industrial Revolution, the continent became the main leader for the discovery of new products and new industrial production processes. The aim of this study is to shed light on paper and ink production processes during this key historical period. In this study we have chosen some documents preserved in the archive of the Soprintendenza dei Beni Architettonici e Paesaggistici (B.A.P.) di Venezia e Laguna, held in the Palazzo Ducale (Ducal Palace) of Venice. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FT-IR), and inductively coupled plasma-mass spectrometry (ICP-MS) allowed us to obtain a qualitative and quantitative characterization of the organic and inorganic components in both paper and inks. Cluster analysis and principal component analysis (PCA) were employed for statistical analysis of the results. 相似文献
34.
The versatility of using a stochastic pulse sequence to elucidate peaks with a wide range of shifts, peak widths, and T(1) relaxation times is demonstrated. A stochastic sequence is combined with high speed magic angle spinning (MAS) to obtain the broad and largely shifted peak associated with (31)P in LiNiPO(4). A stochastic sequence is also used to obtain a spectrum of 85% H(3)PO(4), which has a much longer T(1) value. The signal-to-noise was comparable for spectra of 85% H(3)PO(4) obtained with either a stochastic sequence or an optimized Ernst angle experiment. Experimental parameters for the stochastic experiment are set depending only on the ringdown of the probe and not on any inherent qualities of the sample. A stochastic sequence, therefore, combined with MAS provides a useful strategy for finding peaks with unknown T(1) relaxation constants, peak widths, and shifts. 相似文献
35.
Chalmers S Caldwell ST Quin C Prime TA James AM Cairns AG Murphy MP McCarron JG Hartley RC 《Journal of the American Chemical Society》2012,134(2):758-761
Depolarization of an individual mitochondrion or small clusters of mitochondria within cells has been achieved using a photoactivatable probe. The probe is targeted to the matrix of the mitochondrion by an alkyltriphenylphosphonium lipophilic cation and releases the protonophore 2,4-dinitrophenol locally in predetermined regions in response to directed irradiation with UV light via a local photolysis system. This also provides a proof of principle for the general temporally and spatially controlled release of bioactive molecules, pharmacophores, or toxins to mitochondria with tissue, cell, or mitochondrion specificity. 相似文献
36.
Kaaki K Hervé-Aubert K Chiper M Shkilnyy A Soucé M Benoit R Paillard A Dubois P Saboungi ML Chourpa I 《Langmuir : the ACS journal of surfaces and colloids》2012,28(2):1496-1505
We report the efficient one-step synthesis and detailed physicochemical evaluation of novel biocompatible nanosystems useful for cancer therapeutics and diagnostics (theranostics). These systems are the superparamagnetic iron oxide nanoparticles (SPIONs) carrying the anticancer drug doxorubicin and coated with the covalently bonded biocompatible polymer poly(ethylene glycol) (PEG), native and modified with the biological cancer targeting ligand folic acid (PEG-FA). These multifunctional nanoparticles (SPION-DOX-PEG-FA) are designed to rationally combine multilevel mechanisms of cancer cell targeting (magnetic and biological), bimodal cancer cell imaging (by means of MRI and fluorescence), and bimodal cancer treatment (by targeted drug delivery and by hyperthermia effect). Nevertheless, for these concepts to work together, the choice of ingredients and particle structure are critically important. Therefore, in the present work, a detailed physicochemical characterization of the organic coating of the hybrid nanoparticles is performed by several surface-specific instrumental methods, including surface-enhanced Raman scattering (SERS) spectroscopy, X-ray photoelectron spectrometry (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). We demonstrate that the anticancer drug doxorubicin is attached to the iron oxide surface and buried under the polymer layers, while folic acid is located on the extreme surface of the organic coating. Interestingly, the moderate presence of folic acid on the particle surface does not increase the particle surface potential, while it is sufficient to increase the particle uptake by MCF-7 cancer cells. All of these original results contribute to the better understanding of the structure-activity relationship for hybrid biocompatible nanosystems and are encouraging for the applications in cancer theranostics. 相似文献
37.
David Blake Kevin Dowd Andrew J.G. Cairns 《Insurance: Mathematics and Economics》2008,42(3):1062-1066
This paper uses survivor fan charts to illustrate the prospective density functions of future male survival rates. The fan charts are based on a version of the Cairns–Blake–Dowd model of male mortality that provides a good fit to recent mortality data for England and Wales. They indicate that although none of us can escape the Grim Reaper, survivorship uncertainty is greatest for males aged a little over 90, confirming that there exists a ‘toxic tail’ for those institutions, such as annuity and pension providers, which are obliged to make payments to them for as long as they live. We also find that taking account of uncertainty in the parameters of the underlying mortality model leads to major increases in estimates of the widths of the fan charts. 相似文献
38.
Legros C Célérier ML Henry M Guette C 《Rapid communications in mass spectrometry : RCM》2004,18(10):1024-1032
Mass spectrometric methods, including matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS), on-line liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS), and nanospray ionisation/hybrid quadrupole time-of-flight mass spectrometry (nanoESI-QqTOFMS), were applied to characterize by mass fingerprinting the venom of the French Guyanese tarantula Theraphosa leblondi. Of these techniques direct nanoESI-QqTOFMS, which allowed the detection of 65 protonated molecules with high mass accuracy, appeared to give the best results. Three major peptides, TlTx1, TlTx2 and TlTx3, were sequenced using a combination of nanoESI-MS/MS and enzyme digestion/MS and MS/MS experiments. Each sequence was confirmed by automated Edman sequencing. In patch-clamp experiments these peptides were found to have a specific inhibitory effect on the voltage-dependent potassium channel, Kv4.2. 相似文献
39.
Recombinant human estrogen, androgen and progesterone receptors for detection of potential endocrine disruptors 总被引:9,自引:0,他引:9
Scippo ML Argiris C Van De Weerdt C Muller M Willemsen P Martial J Maghuin-Rogister G 《Analytical and bioanalytical chemistry》2004,378(3):664-669
This work reports the binding capacity of various chemicals (so-called endocrine disruptors) to recombinant human steroid receptors (hER, hPR and hAR). The tested chemicals are organochlorine insecticides (DDT and its metabolites, methoxychlor, aldrin, dieldrin, chlordecone, lindane, trichlorobenzene), estrogenic insecticides (endosulfan, toxaphene, nonachlor), herbicides (alachlor and atrazine), fungicides (benomyl and vinclozolin), industrial chemicals (nonylphenol, bisphenol A, diphenylphtalate), antioxidants (butylated hydroxyanisol) and some phytoestrogens. Except for phytoestrogens, most of the tested chemicals (DDT and its metabolites, aldrin, - and -endosulfan, toxaphen, trans-nonachlor) show higher affinities for hPR than for hER, indicating that the interaction with the progesterone receptor could contribute to the endocrine-disrupting effects imputed to these chemicals. We propose to use binding assays using recombinant human steroid receptors as screening tools for the detection of endocrine disruptors in various samples. 相似文献
40.
Sophie Danyi François Brose Yves-Jacques Schneider Luc Pussemier Sarah De Saeger Marie-Louise Scippo 《Analytica chimica acta》2009,633(2):293-6318
High performance liquid chromatography coupled to an ultraviolet, diode array or fluorescence detector (HPLC/UV-FLD) has been used to set up a method to detect the 15(+1) EU priority polycyclic aromatic hydrocarbons (PAHs) in food supplements covering the categories of dried plants and plant extracts excluding oily products. A mini validation was performed and the following parameters have been determined: limit of detection, limit of quantification, precision, recovery and linearity. They were in close agreement with quality criteria described in the Commission Regulation (EC) No 333/2007 concerning the PAH benzo[a]pyrene in foodstuffs, except the not fluorescent cyclopenta[c,d]pyrene for which the UV detection leads to a higher limit of detection. Analysis of twenty commercial food supplements covering mainly the class of dried plants was performed to evaluate their PAHs contamination levels and to test the applicability of the method to various plant matrices. Fifty percent of analyzed samples showed concentration exceeding 2 μg kg−1 for one or more PAHs. 相似文献