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排序方式: 共有260条查询结果,搜索用时 625 毫秒
81.
Enrico Marchetti Roland Brast Bernard Delabre Rob Donaldson Enrico Fedrigo Christoph Frank Norbert Hubin Johann Kolb Miska Le Louarn Jean-Louis Lizon Sylvain Oberti Fernando Quirs-Pacheco Roland Reiss Joana Santos Sebastien Tordo Elise Vernet Roberto Ragazzoni Carmelo Arcidiacono Paolo Bagnara Andrea Baruffolo Emiliano Diolaiti Jacopo Farinato Matteo Lombini 《Comptes Rendus Physique》2005,6(10):1118-1128
The European Southern Observatory (ESO) together with external research institutes have built a Multi-Conjugate Adaptive Optics (MCAO) Demonstrator (MAD) to perform wide field-of-view adaptive optics correction (2′ in K band). The aim of MAD is to demonstrate the on-sky feasibility of the MCAO technique and to evaluate its critical aspects in the framework of both the 2nd generation instrumentation for the Very Large Telescope (VLT) and the Overwhelmingly Large Telescope (OWL). The MAD module will be installed on the VLT to perform on-sky observations. MAD comprises two deformable mirrors and two different multi-reference wavefront sensors with natural guide stars. In this article we present the MAD design, some aspects of the MAD calibration and the first closed-loop results in the laboratory in Single Conjugated Adaptive Optics (SCAO) and Ground Layer Adaptive Optics (GLAO) configurations. To cite this article: E. Marchetti et al., C. R. Physique 6 (2005). 相似文献
82.
We present an algorithm for automatic integration over an N-dimensional sphere. The quadrature formula is obtained by using a trapezoidal rule after a non-linear transformation, and allows to deal with integrand singularities on the surface or in the centre of the sphere.At the basis of the theoretical development lie the construction and the selection of suitable transformations.The algorithm is cast into an automatic integration program coded as a Standard Fortran sub-routine. 相似文献
83.
The reaction of [60]fullerene with organolithium and Grignard reagents carrying orthoester, acetal or other end groups yielded adducts 3-5 at the 6-6 bond of C60 after quenching with trifluoroacetic acid. The adducts could be easily methylated or benzylated with methyl iodide or benzyl bromide in the presence of potassium tert-butoxide to yield exclusively the 1,4-disubstituted C60 6 and 7a,b. Cleavage of the orthoester, acetal and silylether groups gave the corresponding carboxylic acid 9, aldehydes 10a,b and 11 and alcohols 12 and 13a,b. The carboxylic acid 9 readily reacted with alanine ethyl ester under standard peptide coupling conditions to give 14 in 55% yield. Attempts to generate a silyl enol ether from the reaction of aldehyde 10b with TIPSOTf and triethylamine failed. Instead the reaction led to a cyclized ether 16a (or alcohol 16b in the absence of silylating agent) resulting from the addition of an initially formed fulleride anion to the aldehyde group. The corresponding acetal 4b reacted similarly. The reaction of aldehyde 10b with aniline also gave a cyclized product 19. Surprisingly, aldehyde 11, which no longer carried an acidic fullerene proton reacted with aniline to give a product 20 resulting from an intramolecular Diels-Alder reaction followed by aromatization of a primarily formed N-phenylimine. Alcohol 13b could be readily converted to the corresponding bromide using tetramethyl-α-bromoenamine. The bromide was reacted with the carbanion derived from the protected glycine derivative to yield the diastereomeric fullerene amino acid derivatives 1-benzyl-4-[α-propyl-tert-butylglycinate benzophenone imine] 1,4-dihydro[60]fullerenes 24a and 24b. 相似文献
84.
Höhler R Sang YY Lorenceau E Cohen-Addad S 《Langmuir : the ACS journal of surfaces and colloids》2008,24(2):418-425
We present an experimental and numerical study of the osmotic pressure in monodisperse ordered foams as a function of the liquid fraction. The data are compared to previous results obtained for disordered monodisperse and polydisperse concentrated emulsions. Moreover, we report a quantitative investigation of the transition from a bubble close packing to a bcc structure as a function of the liquid volume fraction. These findings are discussed in the context of theoretical models that have been proposed in the literature. 相似文献
85.
The dynamics of metal sorption by a gel-like polysaccharide is investigated by means of the electrochemical technique of stripping chronopotentiometry (SCP). The measured response reflects the diffusive flux properties of the metallic species in the dispersion. The colloidal ligand studied here is a functionalized carboxymethyldextran. Its complexation with Pb(II) reveals a time dependence that identifies strong differences in the dynamic nature of the successive metal complexes formed. Apparently, the formation of intramolecular bidentate complexes requires a slow conformational reorganization of the macromolecule that becomes the rate-limiting step in the complexation reaction. The relevant parameters for metal binding and release kinetics are computed and thus provide knowledge of the time-dependent stability and lability of metal polysaccharide complexes. 相似文献
86.
Seeley JV Seeley SK Libby EK Breitbach ZS Armstrong DW 《Analytical and bioanalytical chemistry》2008,390(1):323-332
A high-temperature ionic liquid, trihexyl(tetradecyl)phosphonium bis(trifluoromethane)sulfonamide, was used as the primary
column stationary phase for comprehensive two-dimensional gas chromatography (GC × GC). The ionic liquid (IL) column was coupled
to a 5% diphenyl/95% dimethyl polysiloxane (HP-5) secondary column. The retention characteristics of the IL column were compared
to polyethylene glycol (DB-Wax) and 50% phenyl/50% methyl polysiloxane (HP-50+). A series of homologous compounds that included
hydrocarbons, oxygenated organics, and halogenated alkanes were analyzed with each column combination. This comparison showed
that the ionic liquid is less polar than DB-Wax but more polar than HP-50+. The most unique feature of the IL × HP-5 column
combination is that alkanes, cyclic alkanes, and alkenes eluted in a narrow band in the GC × GC chromatogram; whereas, these
compounds occupied a much larger portion of the DB-Wax × HP-5 and the HP-50+ × HP-5 chromatograms. Each column combination
was used to analyze diesel fuel. The IL × HP-5 chromatogram displayed narrow bands for three major compound classes in diesel
fuel: saturates, monoaromatics, and diaromatics. The IL column was used at temperatures as high as 290 °C for several months
without any noticeable changes in column performance. 相似文献
87.
Dr. Claudia Herrera León Noel Angelo Kalacas Dr. Alejandra Mier Dr. Peyman Sakhaii Dr. Franck Merlier Elise Prost Dr. Irene Maffucci Dr. Valentina Montagna Dr. Helena Mora-Radó Dr. Pradeep K. Dhal Dr. Bernadette Tse Sum Bui Prof. Dr. Karsten Haupt 《Angewandte Chemie (International ed. in English)》2023,62(34):e202306274
Tumor Necrosis Factor-α (TNF-α) is a cytokine that is normally produced by immune cells when fighting an infection. But, when too much TNF-α is produced as in autoimmune diseases, this leads to unwanted and persistent inflammation. Anti-TNF-α monoclonal antibodies have revolutionized the therapy of these disorders by blocking TNF-α and preventing its binding to TNF-α receptors, thus suppressing the inflammation. Herein, we propose an alternative in the form of molecularly imprinted polymer nanogels (MIP-NGs). MIP-NGs are synthetic antibodies obtained by nanomoulding the 3-dimensional shape and chemical functionalities of a desired target in a synthetic polymer. Using an in-house developed in silico rational approach, epitope peptides of TNF-α were generated and ‘synthetic peptide antibodies’ were prepared. The resultant MIP-NGs bind the template peptide and recombinant TNF-α with high affinity and selectivity, and can block the binding of TNF-α to its receptor. Consequently they were applied to neutralize pro-inflammatory TNF-α in the supernatant of human THP-1 macrophages, leading to a downregulation of the secretion of pro-inflammatory cytokines. Our results suggest that MIP-NGs, which are thermally and biochemically more stable and easier to manufacture than antibodies, and cost-effective, are very promising as next generation TNF-α inhibitors for the treatment of inflammatory diseases. 相似文献
88.
Adel Noubigh Mourad Cherif Elise Provost Manef Abderrabba 《The Journal of chemical thermodynamics》2008,40(11):1612-1616
This paper is continuation of the study concerning the solubility-temperature dependence data for some phenolic compounds (PhC), contained in olive mill wastewater (OMWW), in two nitrate salts (KNO3 and NaNO3) aqueous solutions. The solubilities of PhC were determined in the temperature ranging from (293.15 to 318.15) K. It has been observed that the solubility, in aqueous nitrate solutions, increases with increasing temperature. Results showed that alkali metal nitrate has a salting-out effect on the solubility of PhC. The effect of the anion of the electrolyte on the solubility of PhC is observed by comparing these results with values reported in the previous papers for the effect of LiCl, NaCl and KCl. For each cation, the solubilites of the phenolic compounds are higher with nitrate anion than with chloride anion. Results were interpreted in terms of the salt hydration shells and the ability of the solute to form hydrogen-bond with water. The solubility data were accurately correlated by a semi empirical equation. The standard molar Gibbs free energies of transfer of PhC (ΔtrG°) from pure water to aqueous solutions of the nitrate salts have been calculated from the solubility data. The decrease in solubility is correlated to the positive ΔtrG° value which is mainly of enthalpic origin. 相似文献
89.
Plastic Antibodies for Cosmetics: Molecularly Imprinted Polymers Scavenge Precursors of Malodors 下载免费PDF全文
Sofia Nestora Franck Merlier Dr. Selim Beyazit Elise Prost Dr. Luminita Duma Bérangère Baril Dr. Andrew Greaves Prof. Karsten Haupt Dr. Bernadette Tse Sum Bui 《Angewandte Chemie (International ed. in English)》2016,55(21):6252-6256
Molecularly imprinted polymers (MIPs) are synthetic antibody mimics capable of specific molecular recognition. Advantageously, they are more stable, easy to tailor for a given application and less expensive than antibodies. These plastic antibodies are raising increasing interest and one relatively unexplored domain in which they could outplay these advantages particularly well is cosmetics. Here, we present the use of a MIP as an active ingredient of a cosmetic product, for suppressing body odors. In a dermo‐cosmetic formulation, the MIP captures selectively the precursors of malodorous compounds, amidst a multitude of other molecules present in human sweat. These results pave the way to the fabrication of a novel generation of MIPs with improved selectivities in highly complex aqueous environments, and should be applicable to biotechnological and biomedical areas as well. 相似文献
90.
Elise A. Dennis Alexander W. Gundlach-Graham Steven J. Ray Christie G. Enke Gary M. Hieftje 《Journal of the American Society for Mass Spectrometry》2016,27(11):1772-1786
Distance-of-flight mass spectrometry (DOFMS) separates ions of different mass-to-charge (m/z) by the distance they travel in a given time after acceleration. Like time-of-flight mass spectrometry (TOFMS), separation and mass assignment are based on ion velocity. However, DOFMS is not a variant of TOFMS; different methods of ion focusing and detection are used. In DOFMS, ions are driven orthogonally, at the detection time, onto an array of detectors parallel to the flight path. Through the independent detection of each m/z, DOFMS can provide both wider dynamic range and increased throughput for m/z of interest compared with conventional TOFMS. The iso-mass focusing and detection of ions is achieved by constant-momentum acceleration (CMA) and a linear-field ion mirror. Improved energy focus (including turn-around) is achieved in DOFMS, but the initial spatial dispersion of ions remains unchanged upon detection. Therefore, the point-source nature of surface ionization techniques could put them at an advantage for DOFMS. To date, three types of position-sensitive detectors have been used for DOFMS: a microchannel plate with a phosphorescent screen, a focal plane camera, and an IonCCD array; advances in detector technology will likely improve DOFMS figures-of-merit. In addition, the combination of CMA with TOF detection has provided improved resolution and duty factor over a narrow m/z range (compared with conventional, single-pass TOFMS). The unique characteristics of DOFMS can enable the intact collection of large biomolecules, clusters, and organisms. DOFMS might also play a key role in achieving the long-sought goal of simultaneous MS/MS. 相似文献