Material category of visual objects computed from specular image structure.

Recognizing materials and their properties visually is vital for successful interactions with our environment, from avoiding slippery floors to handling fragile objects. Yet there is no simple mapping of retinal image intensities to physical properties. Here, we investigated what image information drives material perception by collecting human psychophysical judgements about complex glossy objects. Variations in specular image structure-produced either by manipulating reflectance properties or visual features directly-caused categorical shifts in material appearance, suggesting that specular reflections provide diagnostic information about a wide range of material classes. Perceived material category appeared to mediate cues for surface gloss, providing evidence against a purely feedforward view of neural processing. Our results suggest that the image structure that triggers our perception of surface gloss plays a direct role in visual categorization, and that the perception and neural processing of stimulus properties should be studied in the context of recognition, not in isolation.

A novel classification and online platform for planning and documentation of medical applications of additive manufacturing.

Additive manufacturing technologies are widely used in industrial settings and now increasingly also in several areas of medicine. Various techniques and numerous types of materials are used for these applications. There is a clear need to unify and harmonize the patterns of their use worldwide. We present a 5-class system to aid planning of these applications and related scientific work as well as communication between various actors involved in this field. An online, matrix-based platform and a database were developed for planning and documentation of various solutions. This platform will help the medical community to structurally develop both research innovations and clinical applications of additive manufacturing. The online platform can be accessed through http://www.medicalam.info.

Diversity of containers and buildings infested with Aedes aegypti in Puerto Iguazú, Argentina.

Aedes aegypti is the main domestic vector of the dengue virus. Control measures to prevent dengue transmission focus on the treatment and elimination of this vector's oviposition sites. There is limited biological information on Ae. aegypti in Argentina. The aim of this study was to characterize Ae. aegypti oviposition sites in the city of Puerto Iguazú, Argentina. We surveyed an area covering nine neighborhoods in 2005. We identified 191 premises as positive for Ae. aegypti, giving a general house index of 9.6%. Premises classified as residential and vacant lots presented the highest number of infested premises, with 9% and 22% respectively. The total number of surveyed containers was 29,600. The overall container index (CI) was 1.1. The most frequently infested containers were water tanks (CI = 37). These preliminary results suggest that vacant lots and water tanks provide suitable breeding areas and environmental conditions, improving the chances of Ae. aegypti survival in Puerto Iguazú.

Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins.

The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers.

Waste management in Greenland: current situation and challenges.

Waste management in Greenland (56,000 inhabitants) is characterized by landfilling, incineration and export to Denmark of small quantities of metals and hazardous waste. The annual amount of waste is estimated to about 50,000 tons but actual data are scarce. Data on the waste composition is basically lacking. The scattered small towns and settlements, the climate and the long transport distances between towns and also to recycling industries abroad constitute a complex situation with respect to waste management. The landfills have no collection of gas and leachate and the incinerators are small and equipped with only moderate flue gas cleaning technology. This report summarizes the current waste management situation in Greenland and identifies important challenges in improving the waste management.

Characterization of household waste in Greenland.

The composition of household waste in Greenland was investigated for the first time. About 2tonnes of household waste was sampled as every 7th bag collected during 1 week along the scheduled collection routes in Sisimiut, the second largest town in Greenland with about 5400 inhabitants. The collection bags were sorted manually into 10 material fractions. The household waste composition consisted primarily of biowaste (43%) and the combustible fraction (30%), including anything combustible that did not belong to other clean fractions as paper, cardboard and plastic. Paper (8%) (dominated by magazine type paper) and glass (7%) were other important material fractions of the household waste. The remaining approximately 10% constituted of steel (1.5%), aluminum (0.5%), plastic (2.4%), wood (1.0%), non-combustible waste (1.8%) and household hazardous waste (1.2%). The high content of biowaste and the low content of paper make Greenlandic waste much different from Danish household waste. The moisture content, calorific value and chemical composition (55 elements, of which 22 were below detection limits) were determined for each material fraction. These characteristics were similar to what has been found for material fractions in Danish household waste. The chemical composition and the calorific value of the plastic fraction revealed that this fraction was not clean but contained a lot of biowaste. The established waste composition is useful in assessing alternative waste management schemes for household waste in Greenland.

Comparison of dust released from sanding conventional and nanoparticle-doped wall and wood coatings.

Introduction of engineered nanoparticles (ENPs) into traditional surface coatings (e.g., paints, lacquers, fillers) may result in new exposures to both workers and consumers and possibly also a new risk to their health. During finishing and renovation, such products may also be a substantial source of exposure to ENPs or aggregates thereof. This study investigates the particle size distributions (5.6 nm-19.8 µm) and the total number of dust particles generated during sanding of ENP-doped paints, lacquers, and fillers as compared to their conventional counterparts. In all products, the dust emissions from sanding were found to consist of five size modes: three modes under 1 µm and two modes around 1 and 2 µm. Corrected for the emission from the sanding machine, the sanding dust, was dominated by 100-300 nm size particles, whereas the mass and surface area spectra were dominated by the micrometer modes. Adding ENPs to the studied products only vaguely affected the geometric mean diameters of the particle modes in the sanding dust when compared to their reference products. However, we observed considerable differences in the number concentrations in the different size modes, but still without revealing a clear effect of ENPs on dust emissions from sanding.

A comparison of nickel-titanium rotary instruments manufactured using different methods and cross-sectional areas: ability to resist cyclic fatigue.

OBJECTIVE: This study examined the effect of the manufacturing methods (ground, electropolished, and twisted) and the cross-sectional area (CSA) of nickel-titanium (NiTi) rotary instruments on their cyclic fatigue resistance. STUDY DESIGN: A total of 80 NiTi rotary instruments (ISO 25/.06 taper) from 4 brands (K3, ProFile, RaCe, and TF) were rotated in a simulated root canal with pecking motion until fracture. The number of cycles to failure (NCF) was calculated. The CSA at 3 mm from the tip of new instruments of each brand was calculated. The correlation between the CSA and NCF was evaluated. All fractured surfaces were analyzed using a scanning electron microscope to determine the fracture mode. RESULTS: The TF instruments were the most resistant to fatigue failure. The resistance to cyclic failure increased with decreasing CSA. All fractured surfaces showed the coexistence of ductile and brittle properties. CONCLUSION: The CSA had a significant effect on the fatigue resistance of NiTi rotary instruments.

Cytotoxic effects of aggregated nanomaterials.

This study deals with cytotoxicity assays performed on an array of commercially manufactured inorganic nanoparticulate materials, including Ag, TiO(2), Fe(2)O(3), Al(2)O(3), ZrO(2), Si(3)N(4), naturally occurring mineral chrysotile asbestos and carbonaceous nanoparticulate materials such as multiwall carbon nanotube aggregates and black carbon aggregates. The nanomaterials were characterized by TEM, as the primary particles, aggregates or long fiber dimensions ranged from 2nm to 20microm. Cytotoxicological assays of these nanomaterials were performed utilizing a murine alveolar macrophage cell line and human macrophage and epithelial lung cell lines as comparators. The nanoparticulate materials exhibited varying degrees of cytoxicity for all cell lines and the general trends were similar for both the murine and human macrophage cell lines. These findings suggest that representative cytotoxic responses for humans might be obtained by nanoparticulate exposures to simple murine macrophage cell line assays. Moreover, these results illustrate the utility in performing rapid in vitro assays for cytotoxicity assessments of nanoparticulate materials as a general inquiry of potential respiratory health risks in humans.

A novel combinatorial approach for understanding microstructural evolution and its relationship to mechanical properties in metallic biomaterials.

The new generation of metallic biomaterials for prosthesis implantation (orthopedic and dental) typically have a Ti base with fully biocompatible alloying additions such as Nb, Ta, Zr, Mo, Fe and Sn. While the binary Ti-Ta and the ternary Ti-Nb-Ta systems are promising, the large composition space afforded by these systems offers tremendous scope in terms of alloy design via optimization of alloy composition and thermomechanical treatment. In the present paper a novel combinatorial approach has been developed for rapidly exploring the microstructural evolution and microstructure-microhardness (or elastic modulus) relationships in these systems. Using directed laser deposition, compositionally graded alloy samples have been fabricated and subsequently heat-treated to affect different microstructures in terms of the volume fraction and distribution of the alpha phase in the beta matrix as a function of composition. Subsequently, composition-specific indentation-based hardness and modulus information has been obtained from these graded samples, and the resulting data have been used to develop relationships between the composition, microstructure and mechanical properties. Such rapid combinatorial assessments can be very useful in optimizing not only the alloy composition but also the desired microstructure for achieving the best combination of properties for specific orthopedic or dental applications.

Hydrolysis rates, methane production and nitrogen solubilisation of grey waste components during anaerobic degradation.

Municipal grey waste (i.e. the remaining fraction in municipal waste management systems in which putrescibles (biowaste) and other recyclables (paper, metals, glass) are source-segregated) was manually sorted into six main fractions on the basis of composition and also separated by sieving (100 mm mesh size) into two fractions, oversized and undersized, respectively. In practice, in waste management plant the oversized fraction is (or will be) used to produce refuse-derived fuel and the undersized landfilled after biological stabilisation. The methane yields and nitrogen solubilisation of the grey waste and the different fractions (all studied samples were first milled to 5 mm particle samples) were determined in a 237-day methane production batch assay and in a water elution test, respectively. The grey waste was found to contained remnants of putrescibles and also a high amount of other biodegradable waste, including packaging, cartons and cardboard, newsprint, textiles and diapers. These waste fractions comprised 41%-w/w of the grey waste and produced 40-210 m3 methane (total solids (TS))(-1) and less than 0.01 g NH4-N kg TS(added)(-1) except diapers which produced 9.8 g NH4-N kg TS(added)(-1) in the batch assays. In the case of the two sieved fractions and on mass bases, most of the methane originated from the oversized fraction, whereas most of the NH4-N was solublised from the undersized fraction. The first-order kinetic model described rather well the degradation of each grey waste fraction and component, showing the different components to be in the range 0.021-0.058 d(-1), which was around one-sixth of the values reported for the source-segregated putrescible fraction of MSW.

Engineered structures for use in disposable incontinence products.

The background and evolution of absorbent disposable hygiene products is discussed. The current technology used to produce disposable hygiene products such as baby diapers, feminine hygiene products and adult incontinence management products is shown to have a number of manufacturing and in-use problems. Alternative technologies, such as multilayer composite webs offer the opportunity to achieve better product weight control, and therefore better control over the other related properties, reduced raw material waste and improved functional characteristics. There are still problems to be resolved when using such composite materials, but the potential of these new technologies has now been established.

Regional shipping strategy assessment based on installing a refuse-derived-fuel process in a municipal incinerator.

The rising prices of raw materials and the concerns of energy recovery have resulted in an increasing interest in processing the waste streams. In recent years, a number of credible surveys have shown that recycling and waste-to-energy processes appear to work well together. Compatibility exists for several reasons related to economic, environmental, political, and social aspects. However, the regional impacts of installing a centralised refused-derived fuel (RDF) process prior to waste-to-energy facilities remain unclear due to the inherent complexity of solid waste composition, generation rate, energy and material recovery goals, and the existing shipping patterns. This paper illustrates a thorough evaluation for a RDF pilot study from both quantitative and qualitative aspects. Such a process, consisting of the standard unit operations of shredding, magnetic separation, trommel screening, and air classification, might be useful for integrating the recycling and presorting efforts with a large-scale municipal incinerator in a region. A series of sampling and analyses of the waste streams were performed in Taipei County, Taiwan in order to characterise its potentials for recycling. Based on the proper estimation of solid waste generation, the goal programming modelling analysis not only focuses on an evaluation of how the waste inflows with different rates of generation, physical and chemical compositions, and heating values in the service areas can be processed by a centralised RDF facility to meet both the energy recovery and throughput requirements in different municipal incinerators but also indicates the optimal shipping pattern associated with several incinerators due to such an installation in a regional sense. A case study designed to explore the regional impacts on shipping patterns in the southwestern of Taipei County, Taiwan verifies the application potential of such a planning methodology.

Artifact category membership and the intentional-historical theory.

Bloom has illustrated a number of complex and interesting phenomena that must be accounted for by any theory of categorization. We agree with Bloom about several important points: that the intended function of an object alone does not account for its categorization; that historical relations among objects can be important in assigning category membership; and that a name bestowed upon an object by a prior source can be an important contributor to categorization of the object. We also agree that intention may enter into category judgments in some cases. Still, we believe that the intentional-historical theory falls short of providing a compelling general account of artifact category membership.