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排序方式: 共有181条查询结果,搜索用时 31 毫秒
1.
Matteo Di Giosia Alice Soldà Markus Seeger Andrea Cantelli Fabio Arnesano Maria I. Nardella Vincenzo Mangini Francesco Valle Marco Montalti Francesco Zerbetto Stefania Rapino Matteo Calvaresi Vasilis Ntziachristos 《Advanced functional materials》2021,31(20):2101527
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications. 相似文献
2.
The TSIMMIS Approach to Mediation: Data Models and Languages 总被引:18,自引:2,他引:16
Hector Garcia-Molina Yannis Papakonstantinou Dallan Quass Anand Rajaraman Yehoshua Sagiv Jeffrey Ullman Vasilis Vassalos Jennifer Widom 《Journal of Intelligent Information Systems》1997,8(2):117-132
TSIMMIS—The Stanford-IBM Manager of Multiple InformationSources—is a system for integrating information. It offers a datamodel and a common query language that are designed to support thecombining of information from many different sources. It also offerstools for generating automatically the components that are needed tobuild systems for integrating information. In this paper we shalldiscuss the principal architectural features and their rationale. 相似文献
3.
Christos L. Chochos Giannis K. Govaris Fotini Kakali Joannis K. Kallitsis Vasilis G. Gregoriou 《Polymer》2005,46(13):4654-4663
New copoly(arylether)s containing substituted terphenyl, quinquephenyl, fluorene and anthracene moieties with aromatic 1,3,4-oxadiazole units were prepared and the resulting copolymers are soluble in common organic solvents. Investigation of their optical properties revealed that they emit blue and yellow light. Moreover, their photovoltaic response was studied in blends with poly(3-hexylthiophene) (P3HT) as the electron donor. Despite the low power conversion efficiencies it was shown that photo-induced electron transfer does take place and the performances are higher than a single layer P3HT device. In addition, an anthracene-fluorene-oxadiazole main chain copolymer (PAFOXD) was also examined in a single layer photovoltaic device and gave one of the highest reported open-circuit voltage (Voc) values in the literature (0.89 V). Finally, a detailed morphological study of the blends and the PAFOXD surface using the atomic force microscopy (AFM) technique, revealed the effect of solvent selection to the preparation of thin films exhibiting the desired performance characteristics. 相似文献
4.
In this paper, a two-unit multistate repairable production system is considered in which preventive maintenance (PM) is implemented in order to improve its dependability and performance. A general model is provided for the production system using a semi-Markov process, for examining system’s limiting behaviour. Apart from combining redundancy with PM, we introduce scenarios like imperfect and failed maintenance which are usually met in real life production systems. For the proposed model, we calculate the availability, the mean time to failure and the total operational cost and we formulate optimisation problems settled with respect to the system’s inspection times. The main aim of our work is to determine the optimal inspection times and consequently the optimal PM policies to be adopted in order to optimise system’s dependability and performance. 相似文献
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7.
Christina Plati Panos Georgiou Vasilis Papavasiliou 《Structure and Infrastructure Engineering》2016,12(9):1127-1136
This article aims to investigate the feasibility of incorporating of an artificial neural network (ANN) as an innovative technique for modelling the pavement structural condition, into pavement management systems. For the development of the ANN, strain assessment criteria are set in order to characterise the structural condition of flexible asphalt pavements with regards to fatigue failure. This initial task is directly followed with the development of an ANN model for the prediction of strains primarily based on in situ field gathered data and not through the usage of synthetic databases. For this purpose, falling weight deflectometer (FWD) measurements were systematically conducted on a highway network, with ground-penetrating radar providing the required pavement thickness data. The FWD data (i.e. deflections) were back-analysed in order to assess strains that would be utilised as output data in the process of developing the ANN model. A paper exercise demonstrates how the developed ANN model combined with the suggested conceptual approach for characterising pavement structural condition with regard to strain assessment could make provisions for pavement management activities, categorising network pavement sections according to the need for maintenance or rehabilitation. Preliminary results indicate that the ANN technique could help assist policy decision makers in deriving optimum strategies for the planning of pavement infrastructure maintenance. 相似文献
8.
Lenihan JS Gavalas VG Wang J Andrews R Bachas LG 《Journal of nanoscience and nanotechnology》2004,4(6):600-604
A new approach to the modification of carbon nanotubes with biomolecules for the development of nanoscale biosensors is presented. Alkaline phosphatase was immobilized on the surface of multi-wall carbon nanotubes utilizing a layer-by-layer methodology. Carbon nanotubes were incubated with streptavidin, resulting in the formation of a protein layer on the surface of the nanotubes. Biotinylated alkaline phosphatase was then allowed to bind to streptavidin, anchoring the sensing protein onto the surface. Electrochemical biosensors were constructed by using carbon nanotubes compacted into pellets. 1-Naphthyl phosphate, which is hydrolyzed by alkaline phosphatase to the electroactive 1-naphthol, was used as a substrate. Electrodes constructed in this manner were observed to generate an electrochemical signal that was a function of substrate concentration. 相似文献
9.
Mitsis GD Poulin MJ Robbins PA Marmarelis VZ 《IEEE transactions on bio-medical engineering》2004,51(11):1932-1943
The effect of spontaneous beat-to-beat mean arterial blood pressure fluctuations and breath-to-breath end-tidal CO2 fluctuations on beat-to-beat cerebral blood flow velocity variations is studied using the Laguerre-Volterra network methodology for multiple-input nonlinear systems. The observations made from experimental measurements from ten healthy human subjects reveal that, whereas pressure fluctuations explain most of the high-frequency blood flow velocity variations (above 0.04 Hz), end-tidal CO2 fluctuations as well as nonlinear interactions between pressure and CO2 have a considerable effect in the lower frequencies (below 0.04 Hz). They also indicate that cerebral autoregulation is strongly nonlinear and dynamic (frequency-dependent). Nonlinearities are mainly active in the low-frequency range (below 0.04 Hz) and are more prominent in the dynamics of the end-tidal CO2-blood flow velocity relationship. Significant nonstationarities are also revealed by the obtained models, with greater variability evident for the effects of CO2 on blood flow velocity dynamics. 相似文献
10.
The pre-dose technique of thermoluminescence for quartz has been used extensively for retrospective dosimetry of quartz and other natural materials. A recently published model that is a modification of the well-known Zimmerman theory is used here to simulate the complete sequence of experimental steps taken during the additive dose version of the pre-dose technique. The results of simulation show how the method can reproduce accurately the accumulated dose or paleodose received by the sample. The solution of the kinetic differential equations elucidates the various electron and hole processes taking place during the experimental pre-dose procedure and shows clearly the mechanism of hole transfer from the reservoir to the luminescence centre caused by heating to the activation temperature. The numerical results show that the pre-dose technique can reproduce the paleodose with an accuracy of +/- 1-5%, even when the paleodose is varied over more than an order of magnitude. New quantitative results are presented for the effect of the test dose and of the calibration beta dose, beta, on the accuracy of the pre-dose technique. The conclusions drawn from the simple model for quartz can be used to make improvements to more general quartz models. 相似文献