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991.
Carlo Giansante Alexandre G. L. Olive Christian Schäfer Guillaume Raffy André Del Guerzo 《Analytical and bioanalytical chemistry》2010,396(1):125-131
Time-resolved confocal fluorescence microscopy is used to image and analyze quantitatively the influence of 1,3,5-trinitrobenzene
on the fluorescence of organic nanofibers. These nanofibers are formed by self-assembly of 2,3-didecyloxyanthracene in methanol
or from solutions drop-casted onto glass surfaces. Amplification of the fluorescence quenching emerges in the nanofibers as
compared to the constituting monomer thus leading to efficient detection of nanomolar concentrations of TNB. The emission
of dry nanofibers on glass is also efficiently quenched by vapors of TNB. 相似文献
992.
Farida Benabdellah Alexandre Seyer Loïc Quinton David Touboul Alain Brunelle Olivier Laprévote 《Analytical and bioanalytical chemistry》2010,396(1):151-162
Mass spectrometry imaging is becoming a more and more widely used method for chemical mapping of organic and inorganic compounds
from various surfaces, especially tissue sections. Two main different techniques are now available: matrix-assisted laser
desorption/ionizaton, where the sample, preliminary coated by an organic matrix, is analyzed by a UV laser beam; and secondary
ion mass spectrometry, for which the target is directly submitted to a focused ion beam. Both techniques revealed excellent
performances for lipid mapping of tissue surfaces. This article will discuss similarities, differences, and specificities
of ion images generated by these two techniques in terms of sample preparation, sensitivity, ultimate spatial resolution,
and structural analysis. 相似文献
993.
Newly obtained data on the critical dynamics of the drifting/fracturing sea ice in the Arctic Ocean were analyzed and compared with published data on the dynamic processes in the Earth’s crust. Substantial similarities were found in the scaling behavior of both geophysical systems; the most important of them is the b-value space/time variability including a pre-failure drop of this parameter. The b-value pattern of the ensemble of drifting ice floes is an analogue of the b-value distribution over areas and depths in tectonic structures. A common feature of the pre-failure state in the cryosphere and in the Earth’s crust is the increased degree of the energy conservation that manifests itself both in the sea ice consolidation prior to basin-wide ice pack fragmentations, and in involving harder geological formations in the fracture process before earthquakes, respectively. From the viewpoint of the conservative SOC concept, this relation between the system’s conservativity and the occurrence of large-scale fracture events means that the expected scale level of failure is determined by the system’s closeness to “true” SOC behavior. 相似文献
994.
Francis Canon Franck Paté Emmanuelle Meudec Thérèse Marlin Véronique Cheynier Alexandre Giuliani Pascale Sarni-Manchado 《Analytical and bioanalytical chemistry》2009,395(8):2535-2545
Numerous protein–polyphenol interactions occur in biological and food domains particularly involving proline-rich proteins,
which are representative of the intrinsically unstructured protein group (IUP). Noncovalent protein–ligand complexes are readily
detected by electrospray ionization mass spectrometry (ESI-MS), which also gives access to ligand binding stoichiometry. Surprisingly,
the study of interactions between polyphenolic molecules and proteins is still an area where ESI-MS has poorly benefited,
whereas it has been extensively applied to the detection of noncovalent complexes. Electrospray ionization mass spectrometry
has been applied to the detection and the characterization of the complexes formed between tannins and a human salivary proline-rich
protein (PRP), namely IB5. The study of the complex stability was achieved by low-energy collision-induced dissociation (CID)
measurements, which are commonly implemented using triple quadrupole, hybrid quadrupole time-of-flight, or ion trap instruments.
Complexes composed of IB5 bound to a model polyphenol EgCG have been detected by ESI-MS and further analyzed by MS/MS. Mild
ESI interface conditions allowed us to observe intact noncovalent PRP–tannin complexes with stoichiometries ranging from 1:1
to 1:5. Thus, ESI-MS shows its efficiency for (1) the study of PRP–tannin interactions, (2) the determination of stoichiometry,
and (3) the study of complex stability. We were able to establish unambiguously both their stoichiometries and their overall
subunit architecture via tandem mass spectrometry and solution disruption experiments. Our results prove that IB5·EgCG complexes
are maintained intact in the gas phase.
相似文献
995.
Teodor Banica Julien Bichon Jean-Marc Schlenker 《Journal of Functional Analysis》2009,257(9):2864-2910
We develop a combinatorial approach to the quantum permutation algebras, as Hopf images of representations of type π:As(n)→B(H). We discuss several general problems, including the commutativity and cocommutativity ones, the existence of tensor product or free wreath product decompositions, and the Tannakian aspects of the construction. The main motivation comes from the quantum invariants of the complex Hadamard matrices: we show here that, under suitable regularity assumptions, the computations can be performed up to n=6. 相似文献
996.
Julien Barral Jacques Peyrière Zhi-Ying Wen 《Probability Theory and Related Fields》2009,144(3-4):615-631
Mandelbrot multiplicative cascades provide a construction of a dynamical system on a set of probability measures defined by inequalities on moments. To be more specific, beyond the first iteration, the trajectories take values in the set of fixed points of smoothing transformations (i.e., some generalized stable laws). Studying this system leads to a central limit theorem and to its functional version. The limit Gaussian process can also be obtained as limit of an “additive cascade” of independent normal variables. 相似文献
997.
Stefan Ankirchner Peter Imkeller Alexandre Popier 《Stochastic Processes and their Applications》2009,119(9):2744-2772
We consider backward stochastic differential equations (BSDEs) with nonlinear generators typically of quadratic growth in the control variable. A measure solution of such a BSDE will be understood as a probability measure under which the generator is seen as vanishing, so that the classical solution can be reconstructed by a combination of the operations of conditioning and using martingale representations. For the case where the terminal condition is bounded and the generator fulfills the usual continuity and boundedness conditions, we show that measure solutions with equivalent measures just reinterpret classical ones. For the case of terminal conditions that have only exponentially bounded moments, we discuss a series of examples which show that in the case of non-uniqueness, classical solutions that fail to be measure solutions can coexist with different measure solutions. 相似文献
998.
Metallic nanostructures were prepared through the alternate immersion of derivatized glass slides in solutions of gold nanoparticles (NPs) and a propanedithiol linker molecule. Nanostructures consisting of 1-17 depositions of gold NPs were synthesized, and these substrates were characterized using UV-vis spectroscopy and atomic force microscopy. Subsequently, the surface-enhanced Raman scattering (SERS) of oxazine 720 was obtained at two excitation wavelengths (632 and 785 nm) from all substrates. Maximum SERS enhancement was observed for 9 and 13 NP depositions for 632 and 785 nm excitations, respectively. The difference in the number of NP depositions required for maximum enhancement is attributed to different wavelengths which can excite distinct aggregate structures within the metallic substrate. Therefore, these NP-containing structures can be "tuned" to yield maximum SERS enhancement for the excitation source being used by varying the number of NP depositions. 相似文献
999.
Scarfogliero M Picquet-Varrault B Salce J Durand-Jolibois R Doussin JF 《The journal of physical chemistry. A》2006,110(38):11074-11081
NO(3) oxidation of methyl, ethyl, propyl, and butyl vinyl ethers has been studied under tropospheric conditions (atmospheric pressure and T = 293 +/- 3 K) in the LISA indoor simulation chamber. NO(3) was produced inside the reactor by thermal decomposition of N(2)O(5) previously added to the air-VOC mixture, and concentrations were monitored using FTIR spectrometry. All the kinetic experiments were carried out by relative rate technique using isoprene as reference compound, leading to the rate constants k(1) = (7.2 +/- 1.5) x 10(-13), k(2) = (13.1 +/- 2.7) x 10(-13), k(3) = (13.3 +/- 3.0) x 10(-13), and k(4) = (17.0 +/- 3.7) x 10(-13) cm(3) molecule(-1) s(-1) for methyl, ethyl, propyl, and butyl vinyl ethers, respectively. Main oxidation products have been identified like being formaldehyde and respectively methyl, ethyl, propyl, and butyl formates. Production yields of oxidation products were close to 50%. Oxygenated nitrates and peroxynitrates were also detected. 相似文献
1000.
Ruas A Guilbaud P Den Auwer C Moulin C Simonin JP Turq P Moisy P 《The journal of physical chemistry. A》2006,110(41):11770-11779