E-waste and the digital transition: Results from a survey of U.S. Households

Until now, only rough estimates were available for the number of televisions (TVs) added to the growing stockpile of obsolete TVs by the June 2009 federally mandated digital transition. This event caused millions of Americans either to replace functioning analog TVs with digital units and purchase cable or satellite service, or to purchase subsidized analog-to-digital converter boxes. In this context, this paper makes two contributions based on results of a survey of 3,156 U.S. households conducted between the end of December 2009 and January 2010. First, we estimate the number of analog TVs that were retired as a result of the digital transition and we analyze the socioeconomic characteristics of the households affected. Second, we quantify the volume of nine metals (antimony, cadmium, chromium, copper, gold, lead, palladium, silver, and zinc) contained in these retired TVs. Our results are important to understand the e-waste consequences of the digital transition and to inform U.S. e-waste policy.     

Adsorption of chitosan and a quaternized derivative on kaolin

Adsorption of Chitosan on kaolin was tested and a comparison was made with a fully quaternized derivative. The influence of pH, molecular weight, and acetyl content on the results was also studied. The adsorption isotherms and the flocculating properties as functions of the various parameters are discussed.     

Curve smoothing for improved feature extraction from digitized pictures

Curves can be expressed by parametrized functions. If a curve is represented by a sampled picture, its parametrized functions appear quantized. The noise induced by quantization can drastically be reduced by an iterative curvilinear filtering of the parametrized functions. At each iteration, this filtering processes the curve coordinates and a better arc length is estimated.     

A coordinate system associated with points scattered on a surface

Coordinate systems associated to a finite set of sample points have been extensively studied, especially in the context of interpolation of multivariate scattered data. Notably, Sibson proposed the so-called natural neighbor coordinates that are defined from the Voronoi diagram of the sample points. A drawback of those coordinate systems is that their definition domain is restricted to the convex hull of the sample points. This makes them difficult to use when the sample points belong to a surface. To overcome this diffculty, we propose a new system of coordinates. Given a closed surface S, i.e. a (d−1)-manifold of the coordinate system is defined everywhere on the surface, is continuous, and is local even if the sampling density is finite. Moreover, it is inherently (d−1)-dimensional while the previous systems are d-dimensional. No assumption is made about the ordering, the connectivity or topology of the sample points nor of the surface. We illustrate our results with an application to interpolation over a surface.     

Formation of an ordered nanostructure in surfactant-polyelectrolyte complexes formed by interfacial diffusion

Summary This paper concerns the obtention of capsules stabilized by a shell formed by an electrostatic complex which also present an ordered nanostructure. The complex involves chitosan as a semi rigid positively charged polyelectrolyte and sodium dodecyl sulphate (SDS) anionic surfactant. The shell consists of a network in which anionic surfactant micelles crosslink the cationic polymer chains. Received: 24 February 2000/Revised version: 26 June 2000/Accepted: 26 June 2000     

Comparison between point and long‐gage FBG‐based strain sensors during a railway bridge load test

Strain is a key parameter in laboratory and bridge load testing. The selection of a strain sensor depends on several factors, including the aim of the test and the specimen material. The application of the right sensor is vital to obtain accurate readings, especially in the case of heterogeneous materials such as concrete. This paper focuses on long‐gage and point fiber Bragg grating‐based strain sensors and their possible applications on concrete elements. First, strain sensors are described, after which long‐gage and point fiber Bragg grating strain sensors are compared in a concrete specimen test, a concrete column test and static and dynamic load tests on a concrete railway bridge. Results show that although it is advisable to use long‐gage sensors when monitoring heterogeneous materials, there are some particular cases were both sensors type can provide accurate strain measurements.     

Comparative properties of hyaluronan and chitosan in aqueous environment

In this paper, our objective is to compare the physico-chemical properties of chitosan (CHIT) and hyaluronic acid (HA), two important polysaccharides often used in biomedical or cosmetic applications. Polymer-polymer interactions as well as polymer-solvent interactions, studied by experiments and by molecular modeling, are discussed for the two biopolymers in presence of aqueous environments. HA and CHIT have similar non-freezing water content, although HA retains more water than CHIT at large degree of relative humidity (RH). Thermal degradation is larger for HA. The specific viscosity at zero shear rate of CHIT deviates from the master curve, whereas that of HA superimposed nicely. The solution viscosity of concentrated solutions of CHIT continuously decreases in the shear rate range between 0.5 up to 100 s^?1, whereas HA shows a Newtonian plateau at low shear rates. Dynamic rheology of semi-diluted solutions of HA shows storage modulus G?? lower than the loss modulus G?? up to 30 g/L but that of CHIT at 20 g/L shows G?? > G?? at nearly the same overlap parameter. The viscosity of CHIT solution is less influenced by temperature than that of HA. These results clearly underline the importance of interchain interactions for CHIT in a good solvent. Molecular modelling is used to provide insights on both the aggregated state and solution state of the two polysaccharides. Interchain interactions in the organized models were predicted larger for CHIT than for HA whereas the interaction between the polysaccharide and the solvent molecules are larger for HA than for CHIT. This approach rationalizes the experimental observations: the higher solvation of HA and the higher ability to aggregate for CHIT.     

Discovery of isoerianin analogues as promising anticancer agents

The cytotoxic activity of a series of 23 new isoerianin derivatives with modifications on both the A and B rings was studied. Several compounds exhibited excellent antiproliferative activity at nanomolar concentrations against a panel of human cancer cell lines. The most cytotoxic compound, isoerianin ( 3 ), strongly inhibits tubulin polymerization in the micromolar range. Moreover, isoerianin leads to G₂/M phase cell‐cycle arrest in H1299 and K562 cancer cells, and strongly induces apoptosis. Isoerianin also disrupts the vessel‐like structures formed by human umbilical vein endothelial cells (HUVECs) in vitro, suggesting that this compound may act as a vascular disrupting agent. It clearly appears that in this compound series, the 1,1‐ethane bridge encountered in isoerianin derivatives can replace the 1,2‐ethane bridge of natural erianin with no loss of activity. This reinforces the bioisosteric replacement approach in the combretastatin series previously reported by our research group.