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951.
Carlos?M.?Matias Jo?o?M.?Sousa M.?Emília?Quinta-Ferreira Mona?Arif Hugh?D.?Burrows 《Journal of fluorescence》2010,20(1):377-380
Fura-2 is widely used as a fluorescent probe to monitor dynamic changes in cytosolic free calcium in cells, where Ca2+ can enter through several types of voltage-operated or ligand-gated channels. However, Fura-2 is also sensitive to other
metal ions, such as zinc, which may be involved in ionic channels and receptors. There is interest, in particular, in studying
the synapses between mossy fibers and CA3 pyramidal cells which contain both calcium and high quantities of free or loosely
bound zinc. We have found, through fluorescence probing, that endogenous zinc inhibits mossy fiber calcium transients. However,
since these results might be explained by an effect of the zinc chelator N,N,N’,N’-tetrakis(2-pyridylmethyl)ethylenediamine
(TPEN) on the spectral properties of Fura-2, we have carried out a validation of the method through fluorescence excitation
spectra of the complex Fura-2/calcium, and show that TPEN does not affect these spectra. This supports the idea that the observed
calcium enhancement is related to a zinc inhibition of presynaptic calcium mechanisms, and confirms the use of the chelator
TPEN as a general procedure for the biophysical study of Ca(II) in the presence of Zn(II) using Fura-2. 相似文献
952.
Alfredo?Macías Abel?Camacho Luis?F.?Barragán-Gil Claus?L?mmerzahl 《General Relativity and Gravitation》2010,42(3):489-508
The canonical quantization for N = 1 supergravity in the context of gravitational minisuperspace described by Gowdy T
3 and Bianchi class A cosmological models is analyzed in order to search for physical states. There are indeed physical states
in the minisuperspace sector of the theory. This fact entails that the non-physical states conjecture has a restricted validity,
and in consequence it cannot be considered a general result. 相似文献
953.
Marcelo T. Oliveira Ana Flávia L. Specian Célia G.T.J. Andrade Emanuele J.G. Fran?a Luciana Furlaneto-Maia Marcia C. Furlaneto 《Micron (Oxford, England : 1993)》2010,41(6):604-608
Candida parapsilosis is found frequently as commensal organism on epithelial tissues, and is also an increasing cause of nosocomial infection. Scanning electron microscope (SEM) observations were used to analyse the capability of C. parapsilosis cells to adhere and grow as biofilm on human natural substrates and to compare the adherence pattern of isolates exhibiting distinct phenotypes. Cells from the crepe phenotype are predominantly elongated and form pseudohyphae whereas cells from the smooth phenotype are yeast-shaped, either in liquid cultures or on human nail and hair surfaces. The electron micrographs revealed that C. parapsilosis cells from the smooth phenotype adhered in higher number to both surfaces compared to the observed for the crepe phenotype. SEM analysis of human hair surface revealed that cells from the smooth phenotype appear as clumped blastoconidia of uniform morphology embedded in a flocculent extracellular material forming biofilm. The extracellular material and biofilm were seeing in a less extension in the crepe phenotype. A distinct adherence pattern was observed when human nail was used as substrate. Here C. parapsilosis cells seem to be linked to surface structures of human nail plate. Fibrillar extracellular material was observed connecting neighbouring cells as well as nail surface. 相似文献
954.
M. C. Fuss A. Mu?oz J. C. Oller F. Blanco P. Lim?o-Vieira A. Williart C. Huerga M. Téllez G. García 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(1):203-208
In this study, an electron-tracking Monte Carlo algorithm developed by us is combined with established photon transport models
in order to simulate all primary and secondary particle interactions in water for incident photon radiation. As input parameters
for secondary electron interactions, electron scattering cross sections by water molecules and experimental energy loss
spectra are used. With this simulation, the resulting energy deposition can be modelled at the molecular level, yielding detailed
information about localization and type of single collision events. The experimental emission spectrum of I-125 seeds, as
used for radiotherapy of different tumours, was used for studying the energy deposition in water when irradiating with this
radionuclide. 相似文献
955.
Leonid Kikot Alexander Lyapunov Tatiana Bogaschenko Sergey Smola Catherine Kulygina 《合成通讯》2013,43(4):478-484
A new facile synthetic route to benzils containing fragments of 12-crown-4, 15-crown-5, and 18-crown-6 by oxidation of corresponding stilbenes was developed. The first representative of a new family of fluorescent sensors was obtained by reaction of bis(15-crown-5)benzil with o-phenylenediamine. The latter exhibits great fluorescence enhancement upon association with K+ and Rb+ compared to Na+ and Cs+. 相似文献
956.
E.?A.?Nenasheva A.?D.?Kanare?kin A.?I.?Dedyk Yu.?V.?Pavlova 《Physics of the Solid State》2009,51(8):1557-1560
This paper reports on the results of an experimental investigation into the dielectric properties of a new composite ceramic material BSM, whose tunability increases with increasing concentration of the composite magnesium-containing additive. The main applications of the ferroelectric ceramic material in the accelerator technology are considered. 相似文献
957.
A. GabrielliI. D?Antone F.M. GiorgiI. Lax M. LolliR. De Leo G. De RobertisM. Foresta F. LoddoA. Ranieri G. CosentinoP. Finocchiaro A.D. PappalardoR. Fonte C. CalviniP. Musico P. OttonelloF. Cusanno F. GaribaldiT. Gigli F. GioveB. Maraviglia F. MeddiA. Rivetti 《Nuclear Physics B - Proceedings Supplements》2011,215(1):165-167
958.
It is shown that the seminal Horodecki 2-qutrit state belongs to the class of states displaying symmetry governed by a commutative subgroup of the unitary group U(3). Taking a conjugate subgroup one obtains another classes of symmetric states and one finds equivalent representations of the Horodecki state. These results are generalized to d⊗d systems. 相似文献
959.
Photonic crystal behavior of a rotating Bose-Einstein condensate with a triangular vortex lattice is reviewed and a scheme for getting much wider band gaps is proposed. It is shown that photonic band gaps can be widened an order of magnitude more by using a Raman scheme of index enhancement, in comparison to previously considered upper level microwave scheme. 相似文献
960.
H. Lavi?ka V. Poto?ek T. Kiss E. Lutz I. Jex 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,64(1):119-129
We analyze a special class of 1-D quantum walks (QWs) realized using optical multi-ports.
We assume non-perfect multi-ports showing errors in the connectivity, i.e. with a small
probability the multi-ports can connect not to their nearest neighbor but to another
multi-port at a fixed distance – we call this a jump. We study two cases of QW with jumps
where multiple displacements can emerge at one timestep. The first case assumes
time-correlated jumps (static disorder). In the second case, we choose the positions of
jumps randomly in time (dynamic disorder). The probability distributions of position of
the QW walker in both instances differ significantly: dynamic disorder leads to a
Gaussian-like distribution, while for static disorder we find two distinct behaviors
depending on the parity of jump size. In the case of even-sized jumps, the distribution
exhibits a three-peak profile around the position of the initial excitation, whereas the
probability distribution in the odd case follows a Laplace-like discrete distribution
modulated by additional (exponential) peaks for long times. Finally, our numerical results
indicate that by an appropriate mapping a universal functional behavior of the variance of
the long-time probability distribution can be revealed with respect to the scaled average
of jump size. 相似文献