422 research outputs found
Monitoring nanoparticle dissolution via fluorescence-colour shift
[La(OH)]2+[ICG]â2 and [La(OH)]2+2[PTC]4â inorganicâorganic hybrid nanoparticles (IOH-NPs) with indocyanine green (ICG) and perylene-3,4,9,10-tetracarboxylate (PTC) as fluorescent dye anions are used for emission-based monitoring of the dissolution of nanoparticles. Whereas ICG shows a deep red emission in the solid [La(OH)]2+[ICG]â2 IOH-NPs, the emission of PTC in the solid [La(OH)]2+2[PTC]4â IOH-NPs is completely quenched due to Ï-stacking. After nanoparticle dissolution, the emission of freely dissolved ICG is weak, whereas freely dissolved PTC shows intense green emission. We report on the synthesis of IOH-NPs and nanoparticle characterization as well as on the fluorescence properties and how to avoid undesirable energy transfer between different fluorescent dyes. The emission shift from red (intact solid nanoparticles) to green (freely dissolved dye anions), indicating nanoparticle dissolution, is shown for aqueous systems and verified in vitro. Based on this first proof-of-the-concept, the IOH-NP marker system can be interesting to monitor nanoparticle dissolution in cells and tissues of small animals and to evaluate cell processes and/or drug-delivery strategies
pH-Dependent fluorescence of [La(OH)(2)](+)[ARS](-) hybrid nanoparticles for intracellular pH-sensing
Saline inorganicâorganic hybrid nanoparticles (IOH-NPs) [La(OH)2]+[ARS]â (ARS: alizarin red S) are prepared in water as a new compound (particle size: 47 ± 7 nm, ARS load: 65 wt%). The IOH-NPs not only show a pH-dependent absorption colour but also a pH-dependent fluorescence with green emission at pH 5.0â9.0 and red emission at pH < 4.5. According to first in vitro studies, the pH-dependend fluorescence can be used to monitor nanoparticle internalization in cells as well as the respective intracellular pH
Maximum distance separable 2D convolutional codes
Maximum distance separable (MDS) block codes and MDS 1D convolutional codes are the most robust codes for error correction within the class of block codes of a fixed rate and 1D convolutional codes of a certain rate and degree, respectively. In this paper, we generalize this concept to the class of 2D convolutional codes. For that, we introduce a natural bound on the distance of a 2D convolutional code of rate and degree , which generalizes the Singleton bound for block codes and the generalized Singleton bound for 1D convolutional codes. Then, we prove the existence of 2D convolutional codes of rate and degree that reach such bound when if , or if , by presenting a concrete constructive procedure
Burst Erasure Correction of 2D convolutional codes
In this paper we address the problem of decoding 2D convolutional codes over the erasure channel. In particular, we present a procedure to recover bursts of erasures that are distributed in a diagonal line. To this end we introduce the notion of balls around a burst of erasures which can be considered an analogue of the notion of sliding window in the context of 1D convolutional codes. The main result reduces the decoding problem of 2D convolutional codes to a problem of decoding a set of associated 1D convolutional codes
Implementation of behavioral systems
In this chapter, we study control by interconnection of a given linear
differential system (the plant behavior) with a suitable controller. The problem formulations
and their solutions are completely representation free, and specified only
in terms of the system dynamics. A controller is a system that constrains the plant
behavior through a certain set of variables. In this context, there are two main situations
to be considered: either all the system variables are available for control, i.e.,
are control variables (full control) or only some of the variables are control variables
(partial control). For systems evolving over a time domain (1D) the problems
of implementability by partial (regular) interconnection are well understood. In this
chapter, we study why similar results are not valid in themultidimensional (nD) case.
Finally, we study two important classes of controllers, namely, canonical controllers
and regular controllers
A simple method to estimate the number of doses to include in a bank of vaccines. The case of Lumpy Skin Disease in France
A simple method to estimate the size of the vaccine bank needed to control an epidemic of an exotic infectious disease in case of introduction into a country is presented. The method was applied to the case of a Lumpy Skin disease (LSD) epidemic in France. The size of the stock of vaccines needed was calculated based on a series of simple equations that use some trigonometric functions and take into account the spread of the disease, the time required to obtain good vaccination coverage and the cattle density in the affected region. Assuming a 7-weeks period to vaccinate all the animals and a spread of the disease of 7.3 km/week, the vaccination of 740 716 cattle would be enough to control an epidemic of LSD in France in 90% of the simulations (608 196 cattle would cover 75% of the simulations). The results of this simple method were then validated using a dynamic simulation model, which served as reference for the calculation of the vaccine stock required. The differences between both models in different scenarios, related with the time needed to vaccinate the animals, ranged from 7% to 10.5% more vaccines using the simple method to cover 90% of the simulations, and from 9.0% to 13.8% for 75% of the simulations. The model is easy to use and may be adapted for the control of different diseases in different countries, just by using some simple formulas and few input data
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Reducing the effects of fouling on chlorophyll estimates derived from long-term deployments of optical instruments
Two methods to alleviate the problem of fouling of moored flow tube optical instruments are presented. A chemical method diffuses a concentrated solution of bromine into the flow tube between sampling periods, creating a toxic environment for microorganisms. An optical method removes a baseline value from the red peak of chlorophyll a. Three spectral absorption meters equipped with the chemical system were deployed in the south eastern Bering Sea from March to September 1993. For a 40-, instrument the system prevented biofouling for the entire deployment, while an 11-m instrument was free of contamination for approximately 3.5 months. Reasonable estimates of in situ chlorophyll a were obtained from all three instruments by the subtraction of the baseline
Arbitrage and deflators in illiquid markets
This paper presents a stochastic model for discrete-time trading in financial
markets where trading costs are given by convex cost functions and portfolios
are constrained by convex sets. The model does not assume the existence of a
cash account/numeraire. In addition to classical frictionless markets and
markets with transaction costs or bid-ask spreads, our framework covers markets
with nonlinear illiquidity effects for large instantaneous trades. In the
presence of nonlinearities, the classical notion of arbitrage turns out to have
two equally meaningful generalizations, a marginal and a scalable one. We study
their relations to state price deflators by analyzing two auxiliary market
models describing the local and global behavior of the cost functions and
constraints
Experimental study of the susceptibility of a European Aedes albopictus strain to dengue virus under a simulated Mediterranean temperature regime
Dengue virus (DENV) has reâemerged in Europe driven by the geographic expansion of the mosquito species Aedes albopictus and Aedes aegypti (Diptera: Culicidae) and the introduction of the virus by viraemic travellers. In the present study, the vector competence (VC) of Ae. albopictus collected in Catalonia (northeast Spain) was evaluated for two different DENV strains, DENVâ1 and DENVâ2, the serotypes responsible for all outbreaks of dengue that have occurred in Europe. Mosquitoes were reared under environmental conditions mimicking the mean temperature and humidity recorded in July on the Mediterranean coast of Catalonia. Mosquitoes were fed on an artificial infectious bloodmeal and, at 14âdays postâexposure, infection, disseminated infection and transmission rates (IR, DIR, TR) and transmission efficiency (TE) were determined by testing the virus in the body, legs and saliva. The tested Ae. albopictus strain was found to be susceptible to both DENVâ1 and DENVâ2 and to be able to transmit DENVâ1. This is the first time that the VC of Ae. albopictus for DENV has been tested in Europe in this specific context (i.e. mimicking the Mediterranean temperature and humidity recorded in Catalonia in July). This study confirms the potential of Ae. albopictus to start autochthonous DENV transmission cycles in the Mediterranean basin.info:eu-repo/semantics/publishedVersio
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