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81.
The bioluminescence-dependent oxidation of a long-chain fatty aldehyde catalyzed by luciferase from Photobacterium phosphoreum has been studied in 18O2 experiments. The results show the incorporation of one atom of molecular oxygen into the product, the corresponding fatty acid. This incorporation is not the result of exchange of 18O2 with the aldehyde prior to oxidation to the acid, thereby indicating that the bacterial luciferase catalyzes an aldehyde monooxygenase reaction which is coupled with bioluminescence. 相似文献
82.
83.
ATP is released from the basolateral membrane of A6 epithelia in response to hypotonic treatment. This study addresses the problem of ATP diffusion through the permeable supports used to culture the cells. A theoretical analysis of a recently introduced experimental protocol is presented and a model of ATP diffusion through the compartments of the measuring system is proposed. The model provides the ATP profiles near the cell layer and in the measurement chamber. Comparison of results from computer simulations and experimental data showed that the permeable support introduces a marked delay for ATP diffusion, supporting the correlation of apparently time-separated events: the mobilization of Ca2+ from internal stores and release of ATP from the cell. The model is consistent with experimental data obtained with the luciferin–luciferase pulse protocol and provides an indirect proof of related processes like the closure and opening of the lateral interspace that occur after imposing the hyposmotic shock. The influence of the pore structure of the permeable support in modulating the measured release rates revealed by computer simulation is experimentally validated for two types of Anopore filters. 相似文献
84.
The synthesis and characterisation of [Pt{4′-(Np1)-trpy}(CCPh)]SbF6 (1) and [Pt{4′-(Np1)-trpy}{CC(CH2)2CH3}]SbF6 (2) [4′-(Np1)-trpy = 4′-(1-naphthyl)-2,2:6′,2′-terpyridine] are described. Complexes 1 and 2 exhibit unimolecular 3MLCT (MLCT = metal-to-ligand charge transfer) emission in acetonitrile and in a low concentration 77 K glass solution in butyronitrile. The high concentration glass emission as well as the emission in the solid state is from a 3MMLCT (MMLCT, metal-metal-to-ligand charge transfer) excited state, reflecting the presence of interactions in these media. 相似文献
85.
The single crystal structure of LaPS4, (1), is reported. The space group is tetragonal, I4(1)/acd. Unit cell dimensions are a = 10.9641(3) Å and c = 19.4828(9) Å. The far infrared absorption and Raman spectra (100-600 cm−1) are consistent with the groups being in a distorted tetrahedral geometry. The room temperature emission spectrum of LaPS4 doped with Er3+ is also presented. Emission peaks at 529, 534, 549, and 554 nm were observed when the sample was excited at 492 nm. The compound reported here is isomorphous and isostructural to several other lanthanide orthothiophosphates. 相似文献
86.
87.
Seydack M 《Biosensors & bioelectronics》2005,20(12):2454-2469
Efforts to improve the performance of immunoassays and immunosensors by incorporating different kinds of nanostructures have gained considerable momentum over the last decade. Apart from liposomes, which will not be discussed here, most groups focus on artificial, particulate marker systems, both organic and inorganic. The underlying detection procedures may be based either on electro-magnetical or optical techniques. This review will be confined to the latter only, comprising nanoparticle applications generating signals as diverse as static and time-resolved luminescence, one- and two-photon absorption, Raman and Rayleigh scattering as well as surface plasmon resonance and others. In general, all endeavors cited are geared to achieve one or more of the following goals: lowering of detection limits (if possible, down to single-molecule level), parallel integration of multiple signals (multiplexing), signal amplification by several orders of magnitude and prevention of photobleaching effects with concomitant maintenance of antigen binding specificity and sensitivity. Inorganic nanoparticle labels based on noble metals, semiconductor quantum dots and nanoshells appear to be the most versatile systems for these bioanalytical applications of nanophotonics. 相似文献
88.
Holes pushed into the surface of laboratory grade CaCO3 powder reproduced visible and measurable luminescence similar to that seen and measured in coral skeletons. Heating such
powder to 450 °C for 2 h did not destroy the luminescence although it did destroy luminescence in powdered coral skeleton.
The effect in coral skeletal powder was probably due to carbonisation of contained organics because addition of small and
increasing amounts of powdered charcoal to laboratory grade CaCO3 increasingly attenuated luminescence. Luminescent lines and bands in coral skeletons have previously been ascribed to incorporation
of humic substances. However, coating laboratory grade powder with humic acid attenuates rather than enhances luminescence.
Ultra-violet lamps used to display coral luminescent lines and bands emit significant amounts of violet and blue visible light.
Reflection of these visible wavelengths from the surface of laboratory grade CaCO3 powder obscured luminescence of the powder. Multiple reflections within a hole in the powder resulted in absorption of the
short wavelengths of visible light, including violet and blue light that would otherwise mask luminescence, and their re-emission
at longer wavelengths. Luminescent bands in offshore corals were associated with the low-density regions of the annual density
banding pattern. Luminescent lines in skeletons of inshore corals were in narrow regions of low-density skeleton, probably
resulting from altered growth during periods of lowered salinity.
Accepted: 20 April 2000 相似文献
89.
PurposeThe luminescence images of water during the irradiation of carbon-ions provide useful information such as the ranges and the widths of carbon-ion beams. However, measured luminescence images show higher intensities in shallow depths and wider lateral profiles than those of the dose distributions. These differences prevent the luminescence imaging of water from being applied to a quality assurance for carbon-ion therapy. We assumed that the differences were due to the contaminations of Cerenkov-light from the secondary electrons of carbon-ions as well as the prompt gamma photons in the measured image. In this study, we applied a correction method to a luminescence image of water during the irradiation of carbon-ion beams.MethodsWe estimated the distribution of the Cerenkov-light in water during the irradiation of carbon-ions by Monte Carlo simulation and subtracted the simulated Cerenkov-light from the depth and lateral profiles of the measured luminescence image for 241.5 MeV/u-carbon-ions.ResultsWith these corrections, we successfully obtained depth and lateral profiles whose distributions are almost identical to the dose distributions of carbon-ions. The high intensities in the shallow depth areas decreased and the Bragg peak intensity increased. The beam widths of the measured images approached those of the ionization chamber.ConclusionsThese results indicate that the luminescence imaging of water with our proposed correction has potential to be used for dose distribution measurements for carbon-ion therapy dosimetry. 相似文献
90.
Yu Liu Takuya Kobayashi Masayuki Iizuka Tatsumi Tanaka Izumi Sotokawa Atsushi Shimoyama Yasutoshi Murayama Eigo Otsuji Shun-ichiro Ogura Hideya Yuasa 《Bioorganic & medicinal chemistry》2013,21(11):2832-2842
To create a novel high-throughput lectin assay (HTPLA) method based on the emission of a luminophore by highly penetrable near-infrared excitation, sugar-attached upconversion lanthanide nanoparticles (LNPs) were synthesized as a tool to highlight the aggregates caused by the sugar-mediated specific bridging between LNP and lectin. The emissions from a mannose-coated LNP in the aggregates with a mannose-binding lectin were much stronger than those from the non-aggregated samples, being sensitive enough for HTPLA. A galactose-coated LNP was also applicable to a macrophage aggregation assay for the sugar specificity of its surface lectin. 相似文献