A Bio-Conjugated Fullerene as a Subcellular-Targeted and Multifaceted Phototheranostic Agent

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.     

The TSIMMIS Approach to Mediation: Data Models and Languages

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.     

Combined XPS and TPR study of sulfur removal from a Pt/BaO/Al2O3 NO x storage reduction catalyst

Pt/Al₂O₃ and Pt/BaO/Al₂O₃ catalysts (1 wt% Pt, 10 wt%BaO) were sulfated under conditions simulating a real NSR catalyst operation. Comparative TPR and XPS studies of sulfur removal from Pt/Al₂O₃ and Pt/BaO/Al₂O₃ catalysts indicate that the sulfur removal from Al₂O₃ surface precedes reductive decomposition of BaSO₄ (250–400 °C). Barium sulfate decomposition started with further increase in desulfation temperature at the point of surface atomic ratio Ba:S = 1 (~450^o). Simultaneously, an intensive formation of sulfide species on the catalyst surface was observed. Thermodynamic analysis of the desulfation process allows us to hypothesize that barium sulfide formation may hinder sulfur removal under reducing conditions.     

Synthesis, optical and morphological characterization of soluble main chain 1,3,4-oxadiazole copolyarylethers—potential candidates for solar cells applications as electron acceptors

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 (V_oc) 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.     

Dependability and performance stochastic modelling of a two-unit repairable production system with preventive maintenance

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.     

Simulating pavement structural condition using artificial neural networks

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.     

Effect of preheating on potato texture

Preheating potatoes at 50 to 80°C has a firming effect on the cooked potato tissue. This effect is particularly pronounced at a preheating temperature of 60 to 70°C followed by cooling. Several theories have been presented in the literature to explain this firming effect: retrogradation of starch, leaching of amylose, stabilization of the middle lamellae and cell walls by the activation of the pectin methylesterase (PME) enzyme, and by the release of calcium from gelatinized starch and the formation of calcium bridges between pectin molecules. Most probably, none of these theories alone can explain the phenomenon and more than one mechanism seems to be involved. Some of these mechanisms seem to be interdependent. As an example, calcium could be considered as a link all the way through release after starch gelatinization to cross‐linking pectin substances in the cell wall and the middle lamellae, which has been demethylated by the PME enzyme. More research and “clear cut” experiments are needed in order to elucidate the role of each mechanism, especially which of them is the main contributor to the process of firming. Most probably, the calcium‐pectin‐PME mechanism plays a secondary role, that is, it only retards the collapse of the tissue structure that would otherwise occur during the final heating without preheating, and it is not the main factor of firmness.     

Protein immobilization on carbon nanotubes through a molecular adapter

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.