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41.
Eunkeu Oh Fredrik K. Fatemi Marc Currie James B. Delehanty Thomas Pons Alexandra Fragola Sandrine Lévêque‐Fort Ramasis Goswami Kimihiro Susumu Alan L. Huston Igor L. Medintz 《Particle & Particle Systems Characterization》2013,30(5):453-466
Biocompatible, near‐infrared luminescent gold nanoclusters (AuNCs) are synthesized directly in water using poly(ethylene glycol)‐dithiolane ligands terminating in either a carboxyl, amine, azide, or methoxy group. The ≈1.5 nm diameter AuNCs fluoresce at ≈820 nm with quantum yields that range from 4–8%, depending on the terminal functional group present, and display average luminescence lifetimes approaching 1.5 μs. The two‐photon absorption (TPA) cross‐section and two‐photon excited fluorescence (TPEF) properties are also measured. Long‐term testing shows the poly(ethylene glycol) stabilized AuNCs maintain colloidal stability in a variety of media ranging from saline to tissue culture growth medium along with tolerating storage of up to 2 years. DNA and dye‐conjugation reactions confirm that the carboxyl, amine, and azide groups can be utilized on the AuNCs for carbodiimide, succinimidyl ester, and CuI‐assisted cycloaddition chemistry, respectively. High signal‐to‐noise one‐ and two‐photon cellular imaging is demonstrated. The AuNCs exhibit outstanding photophysical stability during continuous‐extended imaging. Concomitant cellular viability testing shows that the AuNCs also elicit minimal cytotoxicity. Further biological applications for these luminescent nanoclustered materials are discussed. 相似文献
42.
Martino L Virno A Pagano B Virgilio A Di Micco S Galeone A Giancola C Bifulco G Mayol L Randazzo A 《Journal of the American Chemical Society》2007,129(51):16048-16056
The complex between distamycin A and the parallel DNA quadruplex [d(TGGGGT)]4 has been studied by 1H NMR spectroscopy and isothermal titration calorimetry (ITC). To unambiguously assert that distamycin A interacts with the grooves of the quadruplex [d(TGGGGT)]4, we have analyzed the NMR titration profile of a modified quadruplex, namely [d(TGGMeGGT)]4, and we have applied the recently developed differential frequency-saturation transfer difference (DF-STD) method, for assessing the ligand-DNA binding mode. The three-dimensional structure of the 4:1 distamycin A/[d(TGGGGT)]4 complex has been determined by an in-depth NMR study followed by dynamics and mechanics calculations. All results unequivocally indicate that distamycin molecules interact with [d(TGGGGT)]4 in a 4:1 binding mode, with two antiparallel distamycin dimers that bind simultaneously two opposite grooves of the quadruplex. The affinity between distamycin A and [d(TGGGGT)]4 enhances ( approximately 10-fold) when the ratio of distamycin A to the quadruplex is increased. In this paper we report the first three-dimensional structure of a groove-binder molecule complexed to a DNA quadruplex structure. 相似文献
43.
Fort S Birikaki L Dubois MP Antoine T Samain E Driguez H 《Chemical communications (Cambridge, England)》2005,(20):2558-2560
Oligosaccharidic moieties of GM(2) and GM(3) gangliosides bearing an allyl or a propargyl aglycon, are efficiently biosynthesized on the gram scale by growing metabolically engineered Escherichia coli cells in the presence of the corresponding lactoside acceptors and sialic acid. 相似文献
44.
H. B. Kellog Ada M. Kellog G. F. Smith C. A. Getz 《Analytical and bioanalytical chemistry》1937,108(9-10):335-335
45.
Ada rottlaender 《Mathematische Zeitschrift》1928,28(1):641-653
Ohne Zusammenfassung 相似文献
46.
P. Roura J. Costa M. L pez-de Miguel B. Garrido J. Fort J. R. Morante E. Bertran 《Journal of luminescence》1998,80(1-4):519-522
Photoluminescence (PL) experiments on materials of low thermal conductance can cause black-body emission from the sample even at low intensities of laser excitation. This thermal emission may be misinterpreted in terms of quantum emission. Although the quantum origin of most radiative emissions in nanostructured materials such as porous silicon is well established, we show in this paper that SiC nanoparticles and mechanically milled Si do exhibit thermal emission at typical excitation intensities for PL measurements provided the samples are under vacuum. An Si membrane was also investigated and the fact that it did not emit black-body radiation is explained with a simple analysis of the heating in materials of reduced dimensionality. 相似文献
47.
C. Fort A. Bambini L. Cacciapuoti F.S. Cataliotti M. Prevedelli G.M. Tino M. Inguscio 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(2):113-118
We report on a theoretical and experimental investigation of 39K magneto-optical trapping. The small hyperfine splitting characterizing the upper level of the cooling transition affects
the cooling mechanism. In order to model the atom-laser interaction, the whole level structure of the D2 line has to be taken into account. Two different regimes have been recognized, one optimizing the loading of the trap, the
second minimizing the temperature of the atoms. We investigated these two regimes experimentally and found results in agreement
with the theoretical predictions.
Received: 6 March 1998 / Received in final form: 13 May 1998 / Accepted: 13 May 1998 相似文献
48.
N.F. Hettiarachchi R.D. Greenough D. Fort D.W. Jones 《Journal of magnetism and magnetic materials》1982,25(3):310-316
The magnetic susceptibilities of single crystal dysprosium and terbium-50% holmium have been measured in their paramagnetic phases. The effect of annealing has been investigated and heating the sample to ≈ 360 K for ≈ 18 h causes ≈ 4% reduction in χ273. Abrupt departures from Curie-Weiss behaviour occur at ≈ 257, 227, 199 K in Dy, and at 250, 214 and 197 K in Tb-50% Ho, coinciding with previously observed anomalies in the thermal expansion. This behaviour is attributed to the presence of residual antiferromagnetic order in the paramagnetic phase which is perturbed when the periodicity of the helical spin structure, estimated from neutron diffraction data, is commensurate with the hexagonal crystal lattice. 相似文献
49.
Dubois MP Gondran C Renaudet O Dumy P Driguez H Fort S Cosnier S 《Chemical communications (Cambridge, England)》2005,(34):4318-4320
Direct detection of peanut agglutinin/lactose interactions was realized by an electrochemical approach based on a polypyrrole coated electrode displaying pendant carbohydrates. 相似文献
50.
This work is motivated by a problem proposed to the authors by a bakery company in Northern Spain. The objective is to design the daily routes over the week in order to minimize the total traveled distance. For reducing this total distance, some flexibility in the dates of delivery is introduced, which will cause a stock. Therefore, we study the problem under the bi-objective perspective, “minimizing” simultaneously the total traveled distance and the stock. A bi-objective mixed-integer linear model for the problem is formulated and two methodologies of solution are presented. The first one is based on a series of linked variable neighborhood searches and the second one is based on NSGA-II provided of specific operators. Numerical results showing the obtained estimated Pareto front in both cases are presented. 相似文献