Surfactant assisted selective confinement of carbon nanotubes functionalized with octadecylamine in a poly(styrene-b-isoprene-b-styrene) block copolymer matrix

We report how dodecanethiol (DT) surfactant can be used as a good dispersant to solubilize octadecylamine functionalized single-walled carbon nanotubes (ODA-SWCNTs) in order to confine them in the polystyrene phase of the polystyrene-b-polyisoprene-b-polystyrene (SIS) block copolymer matrix. It has been also demonstrated how the block copolymer matrix is not able to self-assemble in ordered morphology when the ODA-SWCNTs are not modified with the surfactant. DT assisted confinement of carbon nanotubes into the PS phase causes not only the nanostructuration of the host polymer matrix but also switches the self-assembled nanostructure from ordered cylinders in the case of neat SIS to a self-assembled lamellar nanostructure.     

Improved myoelectric prosthesis control using targeted reinnervation surgery: a case series.

Targeted reinnervation is a surgical technique developed to increase the number of myoelectric input sites available to control an upper-limb prosthesis. Because signals from the nerves related to specific movements are used to control those missing degrees-of-freedom, the control of a prosthesis using this procedure is more physiologically appropriate compared to conventional control. This procedure has successfully been performed on three people with a shoulder disarticulation level amputation and three people with a transhumeral level amputation. Performance on timed tests, including the box-and-blocks test and clothespin test, has increased two to six times. Options for new control strategies are discussed.     

Semiclosed-Cell Mullite Foams: Preparation and Macro- and Micromechanical Characterization

The preparation and characterization of the properties of mullite ceramic foams suitable for diesel exhaust filtration systems are described. Two foams of different cell sizes, 32 and 61 ppi (pores per inch), were prepared from slurries by the replication process with polyurethane sponges as the templates. The microstructure and the dependence of the porosity and the mechanical properties on the preparation and resulting foam cell size and normalized density are discussed. In addition the micro- and macromechanical properties have been characterized using instrumented indentation techniques; with sharp (Berkovich) and small spherical-tipped indenters the hardness and modulus of the dense strut materials have been measured. The macroproperties have been measured with a large sapphire indenter, ∼5 mm radius using a load partial-unloading technique. The latter enables the modulus and the contact pressure versus penetration to be measured. These values are compared with traditional bulk measurements for crushing strength and elastic modulus. The results are discussed in terms of available theoretical treatments of the indentation of brittle porous materials.     

Synthesis of layered sodium lanthanum selenide through ion exchange reactions

Layered hexagonal KLaSe2 (α-NaFeO₂-type) was synthesized using the reactive flux method and analyzed by powder XRD to determine its lattice constants (space group R-3m, a = 4.40508(5) Å, c = 22.7838(5) Å). NaLaSe₂, which normally crystallizes as a disordered rock salt structure with mixed Na+/La + 3 sites, was synthesized through a solid state ion exchange reaction at 585 °C from a 1:3 molar ratio mixture of KLaSe₂:NaI. The product of this reaction was hexagonally layered NaLaSe₂ (space group R-3m, a = 4.3497(3) Å, c = 20.808(2) Å) isostructural to KLaSe₂. This product was analyzed by comparison with members of the set of solid solutions Na_(1−x)K_(x)LaSe₂ to confirm that the extent ion exchange in this reaction was complete. Cubic (disordered) NaLaSe₂ was also reacted with KI to yield the poorly crystalline hexagonally layered product with the approximate formula Na_0.79K_0.21LaSe₂.     

An impulsive dynamical systems framework for reset control systems

Impulsive dynamical systems is a well-established area of dynamical systems theory, and it is used in this work to analyse several basic properties of reset control systems: existence and uniqueness of solutions, and continuous dependence on the initial condition (well-posedness). The work scope is about reset control systems with a linear and time-invariant base system, and a zero-crossing resetting law. A necessary and sufficient condition for existence and uniqueness of solutions, based on the well-posedness of reset instants, is developed. As a result, it is shown that reset control systems (with strictly proper plants) do not have Zeno solutions. It is also shown that full reset and partial reset (with a special structure) always produce well-posed reset instants. Moreover, a definition of continuous dependence on the initial condition is developed, and also a sufficient condition for reset control systems to satisfy that property. Finally, this property is used to analyse sensitivity of reset control systems to sensor noise. This work also includes a number of illustrative examples motivating the key concepts and main results.     

Selective linking from social platforms to university websites: a case study of the Spanish academic system

Mention indicators have frequently been used in Webometric studies because they provide a powerful tool for determining the degree of visibility and impact of web resources. Among mention indicators, hypertextual links were a central part of many studies until Yahoo! discontinued the ‘linkdomain’ command in 2011. Selective links constitute a variant of external links where both the source and target of the link can be selected. This paper intends to study the influence of social platforms (measured through the number of selective external links) on academic environments, in order to ascertain both the percentage that they constitute and whether some of them can be used as substitutes of total external links. For this purpose, 141 URLs belonging to 76 Spanish universities were compiled in 2010 (before Yahoo! stopped their link services), and the number of links from 13 selected social platforms to these universities were calculated. Results confirm a good correlation between total external links and links that come from social platforms, with the exception of some applications (such as Digg and Technorati). For those universities with a higher number of total external links, the high correlation is only maintained on Delicious and Wikipedia, which can be utilized as substitutes of total external links in the context analyzed. Notwithstanding, the global percentage of links from social platforms constitute only a small fraction of total links, although a positive trend is detected, especially in services such as Twitter, Youtube, and Facebook.     

Technology and independent practice: Survey findings and implications.

Today's rapid rate of technology change introduces both opportunities and challenges for psychologists. A Technology and Practice Questionnaire was sent to 1000 psychologists in independent practice, half of whom were contacted by e-mail and the other half by U.S. mail. A total of 237 of the 433 deliverable surveys sent by U.S. mail were returned (54.7% response rate), but only 49 of the 458 deliverable surveys sent by e-mail (12.9% response rate). Respondents were asked to rate the frequency of 51 behaviors in their practice and to indicate whether the behavior is ethical. The results suggest a relatively low rate of technology use among independent practitioners and a high degree of ethical uncertainty regarding the use of various technologies in practice. Implications for training and practice are considered. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Hydrogen enrichment and separation from synthesis gas by the use of a membrane reactor

One of the objectives of the CHRISGAS project was to study innovative gas separation and gas upgrading systems that have not been developed sufficiently yet to be tested at a demonstration scale within the time frame of the project, but which show some attractive merits and features for further development. In this framework CIEMAT studied, at bench scale, hydrogen enrichment and separation from syngas by the use of membranes and membrane catalytic reactors.In this paper results about hydrogen separation from synthesis gas by means of selective membranes are presented. Studies dealt with the evaluation of permeation and selectivity to hydrogen of prepared and pre-commercial Pd-based membranes. Whereas prepared membranes turned out to be non-selective, due to discontinuities of the palladium layer, studies conducted with the pre-commercial membrane showed that by means of a membrane reactor it is possible to completely separate hydrogen from the other gas components and produce pure hydrogen as a permeate stream, even in the case of complex reaction system (H₂/CO/CO₂/H₂O) under WGS conditions gas mixtures.The advantages of using a water-gas shift membrane reactor (MR) over a traditional fixed bed reactor (TR) have also been studied. The experimental device included the pre-commercial Pd-based membrane and a commercial high temperature Fe–Cr-based, WGS catalyst, which was packed in the annulus between the membrane and the reactor outer shell. Results show that in the MR concept, removal of H₂ from the reaction side has a positive effect on WGS reaction, reaching higher CO conversion than in a traditional packed bed reactor at a given temperature. On increasing pressure on the reaction side permeation is enhanced and hence carbon monoxide conversion increases.     

Optimization of Basic Ingredient Combination for Sandwich Cookie Filling Using Response Surface Methodology

An optimum formulation for a cookie sweet cream filling was selected using response surface methodology (RSM). The formulation included corn starch, powdered sugar, unflavored gelatin, cocoa butter, and distilled water. The effects of the amount of starch (0–30 %), sugar (40–70 %), gelatin solution (5/55 g water) (0–12 %), and cocoa butter (18–30 %) on the water activity and the textural characteristics (firmness, elasticity, relaxation time, adhesiveness, and cohesiveness) of cookie fillings were investigated. Significant regression models, which explained the effects of different percentages of these ingredients on all response variables, were determined. Based on the results, the formulation for the production of a cookie filling with acceptable water activity value and desired texture qualities was obtained by incorporating 23.16 % corn starch, 46.84 % powdered sugar, 0.87 % gelatin solution, and 29.13 % cocoa butter.     

Development of a PCR protocol to detect ochratoxin A producing moulds in food products

Ochratoxin A (OTA) is a mycotoxin produced by several Penicillium and Aspergillus species growing in food commodities. To prevent OTA in foods it is necessary to have rapid and specific methods for early detection of producing moulds regardless of species and genera. In this work a PCR method to detect ochratoxigenic moulds has been developed. For this purpose, 75 mould strains belonging to species usually reported in food products were used. Their OTA production was checked by micellar electrokinetic capillary electrophoresis (MECE) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). A specific amplicon of 459 bp was detected by using the designed PCR protocol only in the OTA producing strains. The detection limit of the developed PCR protocol was estimated for 25 pg of mould DNA from pure cultures and from about 10²–10⁴ cfu/g when it was evaluated directly on artificially inoculated food. Its functionality in naturally infected samples was also demonstrated. In conclusion, the developed PCR method could be used for detecting ochratoxigenic moulds in foods and consequently for monitoring these moulds in the HACCP programs.