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931.
Using the twistorial approach and some previous results, weprove the conjecture that the dimension of the moduli spaceof harmonic maps of area 4d from the 2-sphere to the 2n-sphereis 2d + n2 for the particular case n = 3. 2000 Mathematics SubjectClassification 53A10 (primary), 53C42 (secondary). 相似文献
932.
933.
ChemMatrix, a poly(ethylene glycol)-based support for the solid-phase synthesis of complex peptides 总被引:5,自引:0,他引:5
García-Martín F Quintanar-Audelo M García-Ramos Y Cruz LJ Gravel C Furic R Côté S Tulla-Puche J Albericio F 《Journal of combinatorial chemistry》2006,8(2):213-220
CM (ChemMatrix) resin is a new, totally poly(ethylene glycol) (PEG)-based resin, made exclusively from primary ether bonds and, therefore, highly chemically stable. It exhibits good loading and is user-friendly because of its free-flowing form upon drying. It performs excellently for the preparation of hydrophobic, highly structured, and poly-Arg peptides, as compared to polystyrene (PS) resins. In the most striking example, stepwise solid-phase assembly of the highly complex beta-amyloid (1-42) peptide resulted in a crude material of 91% purity. In contrast, literature procedures using PS or PEG-PS-based resins for this peptide required convergent approaches, additional time-consuming steps, or both. In addition to the difficulties of its synthesis, characterization of the beta-amyloid (1-42) peptide as a monomer is also a challenge, and methods for characterization by HPLC and MALDI-TOF have also been developed. 相似文献
934.
Adams N De Gans BJ Kozodaev D Sanchez C Bastiaansen CW Broer DJ Schubert US 《Journal of combinatorial chemistry》2006,8(2):184-191
A methodology for the rapid design, screening, and optimization of coating systems with surface relief structures, using a combination of statistical experimental design, high-throughput experimentation, data mining, and graphical and mathematical optimization routines was developed. The methodology was applied to photopolymers used in photoembossing applications. A library of 72 films was prepared by dispensing a given amount of sample onto a chemically patterned substrate consisting of hydrophilic areas separated by fluorinated hydrophobic barriers. Film composition and film processing conditions were determined using statistical experimental design. The surface topology of the films was characterized by automated AFM. Subsequently, models explaining the dependence of surface topologies on sample composition and processing parameters were developed and used for screening a virtual 4000-membered in silico library of photopolymer lacquers. Simple graphical optimization or Pareto algorithms were subsequently used to find an ensemble of formulations, which were optimal with respect to a predefined set of properties, such as aspect ratio and shape of the relief structures. 相似文献
935.
Centineo G Rodríguez-González P Blanco González E García Alonso JI Sanz-Medel A Font Cardona N Aranda Mares JL Ballester Nebot S 《Analytical and bioanalytical chemistry》2006,384(4):908-914
A standard GC-MS instrument with electron impact ionisation has been used to develop a fast, simple and reliable method for
the simultaneous determination of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in water samples. Isotope dilution
analysis (IDA) is used for the determination of species, taking advantage of a commercially available spike solution containing
a mixture of MBT, DBT and TBT enriched in 119Sn. Method detection limits for 100-mL samples were between 0.18 and 0.25 ng L−1 for the three butyltin compounds with typical RSD between 2 and 4% at levels between 100 and 10 ng L−1, respectively. Recovery of tin species in spiked samples (natural water, wastewater and seawater) was quantitative. The stability
of butyltin compounds in collected seawater samples was also studied. The addition of a 1% (v/v) glacial acetic acid preserved
tin species in the samples for at least 5 days at room temperature. The IDA method was finally implemented in a routine testing
laboratory and it was subsequently accredited by the Spanish National Accreditation Body according to the requirements of
UNE-EN ISO/IEC 17025. 相似文献
936.
García-Acosta B Comes M Bricks JL Kudinova MA Kurdyukov VV Tolmachev AI Descalzo AB Marcos MD Martínez-Máñez R Moreno A Sancenón F Soto J Villaescusa LA Rurack K Barat JM Escriche I Amorós P 《Chemical communications (Cambridge, England)》2006,(21):2239-2241
Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment. 相似文献
937.
Karbass N Sans V Garcia-Verdugo E Burguete MI Luis SV 《Chemical communications (Cambridge, England)》2006,(29):3095-3097
Long-term stable Pd(0) catalysts can be easily supported onto polymeric monoliths containing methyl-imidazole moieties and the corresponding reactors based on these materials can be applied for the continuous Heck reaction in near-critical EtOH. 相似文献
938.
Rodríguez-Redondo JL Sastre-Santos A Fernández-Lázaro F Soares D Azzellini GC Elliott B Echegoyen L 《Chemical communications (Cambridge, England)》2006,(12):1265-1267
A photoswitchable azobenzene-phthalocyanine-azobenzene triad has been synthesized and its electrochemical properties determined. Energy transfer among the subunits allows for modification of the E-Z ratio by selective excitation of the phthalocyanine moiety. 相似文献
939.
Echegoyen L Chancellor CJ Cardona CM Elliott B Rivera J Olmstead MM Balch AL 《Chemical communications (Cambridge, England)》2006,(25):2653-2655
Crystallographic data for the pyrrolidine adduct Y3N@C80C4H9N x 2.5CS2 reveals a slightly pyramidalized Y3N unit with idealized mirror symmetry that straddles the site of addition but does not directly interact with the addend. 相似文献
940.
The ion complexes NO3-(HNO3)n, n = 1-3, have been studied by means of ab initio calculations at the B3LYP/aug-cc-pVTZ level of theory. These systems are the most abundant anionic clusters below approximately 30 km altitude in the stratosphere and also in the upper troposphere. These complexes display short strong hydrogen bonds, which should be considered to explain their abundance in the atmosphere. Equilibrium geometries, harmonic frequencies, relative energies, and thermochemical data have been calculated for these anions for the first time. The calculations indicate small differences of energy in the variation of the two nitrate groups from planarity to an almost perpendicular form for n = 1. Planar geometries are found for n = 2 and 3 to give rise to a highly symmetric C(3h) NO3-(HNO3)3. In all the cases, binding energies close to those of covalent compounds are estimated. When experimental data are available, good correlations are found with our results. 相似文献