Optical control of energy-level structure of few electrons in AlGaAs/GaAs quantum dots

Optical control of the lateral quantum confinement and number of electrons confined in nanofabricated GaAs/AlGaAs quantum dots is achieved by illumination with a weak laser beam that is absorbed in the AlGaAs barrier. Precise tuning of energy-level structure and electron population is demonstrated by monitoring the low-lying transitions of the electrons from the lowest quantum-dot energy shells by resonant inelastic light scattering. These findings open the way to the manipulation of single electrons in these quantum dots without the need of external metallic gates.     

Cooperative learning strategies to teach nutrition to geriatric nursing staff

The objective of this study was to test the hypothesis that cooperative learning strategies will help to increase nutrition knowledge of nurses and nursing assistants caring for the elderly in different institutional communities of the Basque Country, Spain. The target population was a sample of volunteers, 16 nurses and 28 nursing assistants. Training consisted of 12 nutrition education sessions using cooperative strategies conducted over a period of 3 consecutive weeks. The assessment instruments included two pretest and two posttest questionnaires with questions selected in multiple-choice format. The first questionnaire was about general knowledge of applied nutrition (0-88 point scale) and the second one on geriatric nutrition knowledge (0-18 point scale). Data were analyzed using SPSS vs. 11.0. The outcomes indicated a significant increase in general nutrition knowledge (difference between the pre- and post-test mean score: 14.5+/-10.1; P<0.001) and in geriatric nutrition knowledge for all participants (difference between the pre- and post-test mean score: 4.6+/-4.6; P<0.001). So the results indicated that cooperative learning strategies could improve the nutrition knowledge of nursing staff. Additionally, the results of this study provide direction to continuing nutrition education program planners regarding appropriate content and methodology for programs.     

Holographic lens recorded on photopolymers: fabrication and study of the image quality

In recent years, holographic optical elements have been introduced in different applications such as high-density data storage, interconnections, spatial and temporal filters and three-dimensional displays. Simultaneously, more sensitive, efficient and durable holographic materials have been developed. Thus it is necessary to analyze the characteristics of these elements in the holographic materials developed. In this paper a method to obtain holographic lenses in a photopolymer is presented. In order to obtain, reconstruct and analyze these lenses, an optical device was designed. Once the holographic lenses are obtained, the device allows us to capture the images provided by these lenses. The imaging quality of these lenses was evaluated by means of the modulation transfer function (MTF) and the contrast. Lenses of different focal lengths were recorded. The holographic lenses obtained had high diffraction efficiency and temporal stability. Moreover, the resolution was greater than that of other lenses with the same diaphragm number.     

Quality of Dry‐Cured Ham Compared with Quality of Dry‐Cured Shoulder

The physicochemical and sensory properties of 30 dry‐cured hams and 30 dry‐cured shoulders were analyzed to determine the relationships between them. The variables used to characterize both products were: compositional parameters, instrumental texture, amino acid and fatty acid composition, and sensory profile. Despite being products from the same animal and composed mainly of fat, lean, and bone, their morphological differences determine the conditions of the processing time, which produced differences between products in most of the parameters evaluated. Dry‐cured shoulders showed lower moisture content and greater instrumental hardness due to their morphology and muscular structure. Besides, these samples showed lower amino acid content according to the shorter ripening time. For the same reason, the dry‐cured hams showed higher moisture content, lower instrumental hardness, and higher amino acid content. However, the differences in the muscular structure did not affect the sensory characteristics, which were more related with some compositional parameters, such as chloride, moisture, and amino acid content and with the length of the curing process.     

Study of the effects of multi‐walled carbon nanotubes on mechanical performance and thermal stability of polypropylene

Carbon nanotubes (CNTs) have been added to polypropylene (PP) matrix to improve the overall performance of composites. The mixing process has been carried out by melt compounding using a twin screw co‐rotating extruder with different CNTs amounts in the 0.5–10 wt% from a concentrated PP‐CNTs masterbatch (20 wt% CNTs). Results show a remarkable increase in tensile strength and elastic modulus while a decrease in elongation at break is detected. With regard to thermal behavior, a remarkable increase in thermal stability at high temperatures (decomposition process studied by thermogravimetric analysis) is obtained as the CNTs amount increases. In addition to this improvement, a noticeable increase in thermal stability at medium temperatures (degradation onset determined by differential scanning calorimetry, DSC) is also observed. In a similar way, other property related to thermal and mechanical performance, such as Vicat softening temperature (VST) is improved with CNTs content. The optimum balance between cost and properties seems to be in the 1–3 wt% range. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Gold Nanoparticles Downregulate Interleukin‐1β‐Induced Pro‐Inflammatory Responses

Interleukin 1 beta (IL‐1β)‐dependent inflammatory disorders, such as rheumatoid arthritis and psoriasis, pose a serious medical burden worldwide, where patients face a lifetime of illness and treatment. Organogold compounds have been used since the 1930s to treat rheumatic and other IL‐1β‐dependent diseases and, though their mechanisms of action are still unclear, there is evidence that gold interferes with the transmission of inflammatory signalling. Here we show for the first time that citrate‐stabilized gold nanoparticles, in a size dependent manner, specifically downregulate cellular responses induced by IL‐1β both in vitro and in vivo. Our results indicate that the anti‐inflammatory activity of gold nanoparticles is associated with an extracellular interaction with IL‐1β, thus opening potentially novel options for further therapeutic applications.     

Characterization of a soldering system consisting of a glass from the system CaOAl2O3B2O3SiO2 and wollastonite

In this work, the characterization of a soldering system with wollastonite as filler added as powder to the powdered base glass is shown. A soldering system consisting of the base glass and a coexisting crystalline phase is created which is then pressed to pellets and sintered to maximum density.Wollastonite increases the thermal expansion coefficient of the base glass after sintering the samples. In the present paper, the sintering behavior of the soldering system and possible interactions between glass and filler are analyzed. Also, density and porosity after sintering and the resulting crystalline phases are characterized.The mixtures with wollastonite contents up to 30% showed suitable sintering behavior and good density (low porosity). From 40% wollastonite on, the sintering of the samples was not satisfying and porosity was still high after sintering. The main crystalline phases were anorthite, wollastonite and pseudowollastonite, which occurred in all samples. This shows that all three phases are coexisting phases of the glass composition.     

An Unprecedented Iridium(III) Catalyst for Stereoselective Dimerisation of Terminal Alkynes

A novel iridium(III) hydride complex, IrHCl(TIMP₃) {HTIMP₃=tris[1‐(diphenylphosphino)‐3‐methyl‐1H‐indol‐2‐yl]methane} was prepared and fully characterized in both the solid state and in solution. Chloride abstraction by silver cations provides a more reactive compound, [IrH(TIMP₃)][BF₄], which can react with pyridine (py) and phenylacetylene to yield the complexes [IrH(TIMP₃)(py)][BF₄] and [Ir(PhCHC CHCHPh)(TIMP₃)][BF₄], respectively. Interestingly, IrH(TIMP₃)(py)][BF₄] efficiently catalyses the stereoselective dimerisation of model terminal alkynes to the 1,4‐disubstituted (E)‐but‐1‐en‐3‐yne only.