309 research outputs found
Printable Nanoscopic Metamaterial Absorbers and Images with Diffraction-Limited Resolution
The fabrication of functional metamaterials with extreme feature resolution
finds a host of applications such as the broad area of surface/light
interaction. Non-planar features of such structures can significantly enhance
their performance and tunability, but their facile generation remains a
challenge. Here, we show that carefully designed out-of-plane nanopillars made
of metal-dielectric composites integrated in a metal-dielectric-nanocomposite
configuration, can absorb broadband light very effectively. We further
demonstrate that electrohydrodynamic printing in a rapid nanodripping mode, is
able to generate precise out-of-plane forests of such composite nanopillars
with deposition resolutions at the diffraction limit on flat and non-flat
substrates. The nanocomposite nature of the printed material allows the
fine-tuning of the overall visible light absorption from complete absorption to
complete reflection by simply tuning the pillar height. Almost perfect
absorption (~95%) over the entire visible spectrum is achieved by a nanopillar
forest covering only 6% of the printed area. Adjusting the height of individual
pillar groups by design, we demonstrate on-demand control of the gray scale of
a micrograph with a spatial resolution of 400 nm. These results constitute a
significant step forward in ultra-high resolution facile fabrication of
out-of-plane nanostructures, important to a broad palette of light design
applications. nanostructures, important to a broad palette of light design
applications
Melanin-based colorations signal strategies to cope with poor and rich environments
One hypothesis for the maintenance of genetic variation states that alternative genotypes are adapted to different environmental conditions (i.e., genotype-by-environment interaction G×E) that vary in space and time. Although G×E has been demonstrated for morphological traits, little evidence has been given whether these G×E are associated with traits used as signal in mate choice. In three wild bird species, we investigated whether the degree of melanin-based coloration, a heritable trait, covaries with nestling growth rate in rich and poor environments. Variation in the degree of reddish-brown phaeomelanism is pronounced in the barn owl (Tyto alba) and tawny owl (Strix aluco), and variation in black eumelanism in the barn owl and Alpine swift (Apus melba). Melanin-based coloration has been shown to be a criterion in mate choice in the barn owl. We cross-fostered hatchlings to test whether nestlings sired by parents displaying melanin-based colorations to different extent exhibit alternative growth trajectories when raised by foster parents in poor (experimentally enlarged broods) and rich (experimentally reduced broods) environments. With respect to phaeomelanism, barn owl and tawny owl offspring sired by redder parents grew more rapidly in body mass only in experimentally reduced broods. With respect to eumelanism, Alpine swift offspring of darker fathers grew their wings more rapidly only in experimentally enlarged broods, a difference that was not detected in reduced broods. These interactions between parental melanism and offspring growth rate indicate that individuals display substantial plasticity in response to the rearing environment which is associated with the degree of melanism: at least with respect to nestling growth, phaeomelanic and eumelanic individuals are best adapted to rich and poor environments, respectively. It now remains to be investigated why eumelanism and phaeomelanism have a different signaling function and what the lifelong consequences of these melanism-dependent allocation strategies are. This is important to fully appraise the role played by environmental heterogeneity in maintaining variation in the degree of melanin-based coloratio
Melanin-based colorations signal strategies to cope with poor and rich environments
One hypothesis for the maintenance of genetic variation states that alternative genotypes are adapted to different environmental conditions (i.e., genotype-by-environment interaction G×E) that vary in space and time. Although G×E has been demonstrated for morphological traits, little evidence has been given whether these G×E are associated with traits used as signal in mate choice. In three wild bird species, we investigated whether the degree of melanin-based coloration, a heritable trait, covaries with nestling growth rate in rich and poor environments. Variation in the degree of reddish-brown phaeomelanism is pronounced in the barn owl (Tyto alba) and tawny owl (Strix aluco), and variation in black eumelanism in the barn owl and Alpine swift (Apus melba). Melanin-based coloration has been shown to be a criterion in mate choice in the barn owl. We cross-fostered hatchlings to test whether nestlings sired by parents displaying melanin-based colorations to different extent exhibit alternative growth trajectories when raised by foster parents in poor (experimentally enlarged broods) and rich (experimentally reduced broods) environments. With respect to phaeomelanism, barn owl and tawny owl offspring sired by redder parents grew more rapidly in body mass only in experimentally reduced broods. With respect to eumelanism, Alpine swift offspring of darker fathers grew their wings more rapidly only in experimentally enlarged broods, a difference that was not detected in reduced broods. These interactions between parental melanism and offspring growth rate indicate that individuals display substantial plasticity in response to the rearing environment which is associated with the degree of melanism: at least with respect to nestling growth, phaeomelanic and eumelanic individuals are best adapted to rich and poor environments, respectively. It now remains to be investigated why eumelanism and phaeomelanism have a different signaling function and what the lifelong consequences of these melanism-dependent allocation strategies are. This is important to fully appraise the role played by environmental heterogeneity in maintaining variation in the degree of melanin-based coloration
Full-Spectrum Flexible Color Printing at the Diffraction Limit
Color printing at the diffraction limit has been recently explored by
fabricating nanoscale plasmonic structures with electron beam lithography.
However, only a limited color range and constant intensity throughout the
structure have been demonstrated. Here we show an alternative, facile approach
relying on the direct, open-atmosphere electrohydrodynamic rapid nanodrip
printing of controlled amounts of red, green and blue (RGB) quantum dots at a
resolution of 250 nm. The narrow emission spectrum of the dots allows the
coverage of a very broad color space, exceeding standard RGB (sRGB) of modern
display devices. We print color gradients of variable intensity, which to date
could not be achieved with diffraction-limited resolution. Showcasing the
capabilities of the technology, we present a photo-realistic printed image of a
colorful parrot with a pixel size of 250 nm
NEST – una plataforma para acelerar la innovación en edificios
The speed and quality of innovation in the construction sector has to be substantially increased in order to meet the pressing challenges associated with the building stock. For this purpose, the NEST project was started in Switzerland. NEST is a flexible and open research and technology transfer platform for partners from academia and industry where new solutions can be implemented and validated in a real life environment. NEST consists of a backbone, the static part, and research units which serve as office or living space where people live and work. Each unit is addressing specific research topics such as timber construction or digital fabrication and bears numerous innovation objects which are subject to continuous development and evaluation. NEST is a vertical neighbourhood of units, which are connected to a water hub and an energy hub. Once the research questions in a unit are answered and new products have been developed, the unit is deconstructed and replaced by a new unit addressing new topics.La calidad en la innovación dentro del sector de la construcción debe ser rápidamente adaptada para cumplir con los inmediatos desafÃos relacionados con la mejora de las edificaciones actuales. NEST es una plataforma de investigación y transferencia tecnológica flexible y abierta a universidades e industrias donde nuevas soluciones pueden ser implementadas y validadas en un entorno real. NEST consiste en una estructura fija con una serie módulos individuales que son utilizados como oficinas o apartamentos donde poder vivir y trabajar. Además, cada uno de estos módulos actúa a modo de laboratorio donde se investigan diferentes aspectos como el uso de madera como material de construcción o la fabricación digital y donde, continuamente, se lleva a cabo el desarrollo de materiales innovadores, asà como su evaluación. NEST es un edificio modular cuyas unidades están individualmente conectadas por medio de redes comunes de suministro de energÃa y gestión y tratamiento de aguas. Cuando finalizan los estudios asociados a un módulo y los nuevos productos han sido optimizados, éste es desinstalado y remplazado por una nueva unidad de cara a abordar nuevos retos e investigaciones
A hydrogen peroxide-inactivated virus vaccine elicits humoral and cellular immunity and protects against lethal west nile virus infection in aged mice
West Nile virus (WNV) is an emerging pathogen that is now the leading cause of mosquito-borne and epidemic encephalitis in the United States. In humans, a small percentage of infected individuals develop severe neuroinvasive disease, with the greatest relative risk being in the elderly and immunocompromised, two populations that are difficult to immunize effectively with vaccines. While inactivated and subunit-based veterinary vaccines against WNV exist, currently there is no vaccine or therapy available to prevent or treat human disease. Here, we describe the generation and preclinical efficacy of a hydrogen peroxide (H(2)O(2))-inactivated WNV Kunjin strain (WNV-KUNV) vaccine as a candidate for further development. Both young and aged mice vaccinated with H(2)O(2)-inactivated WNV-KUNV produced robust adaptive B and T cell immune responses and were protected against stringent and lethal intracranial challenge with a heterologous virulent North American WNV strain. Our studies suggest that the H(2)O(2)-inactivated WNV-KUNV vaccine is safe and immunogenic and may be suitable for protection against WNV infection in vulnerable populations
Poor survival outcomes in HER2 positive breast cancer patients with low grade, node negative tumours
We present a retrospective analysis on a cohort of low-grade, node-negative patients showing that human epidermal growth factor receptor 2 (HER2) status significantly affects the survival in this otherwise very good prognostic group. Our results provide support for the use of adjuvant trastuzumab in patients who are typically classified as having very good prognosis, not routinely offered standard chemotherapy, and who as such do not fit current UK prescribing guidelines for trastuzumab
Gold catalysts for the synthesis of aromatic azocompounds from nitroaromatics in one step
[EN] One-step selective hydrogenation of nitroaromatics to obtain symmetric azocompounds with high yields
has been performed with a gold supported on cerium oxide catalysts. Au/TiO2 and Au/CeO2 catalysts
direct the reaction by two different pathways and with different selectivities. In situ FTIR studies reveal
that the surface concentration of the intermediate nitrosobenzene is decisive in directing the reaction
trough the different reaction pathways. In this way, while on Au/TiO2 a fast hydrogenation of the
nitrosobenzene intermediate leads to a low surface concentration of the nitrosocompound, on Au/CeO2
nitrosobenzene is more stabilized on the catalyst surface leading to a lower hydrogenation and a higher
coupling rate, resulting in high selectivities to azobenzene. On Au/CeO2, the relative weak adsorption of
the azo with respect to the azoxycompound on the catalyst surface avoids the consecutive hydrogenation
of azocompounds to the corresponding anilines until all the azoxy has been consumed. Asymmetric
azobenzenes have also been obtained with very high yields on TiO2, through the Mills reaction.The authors wish to acknowledge the financial support from the Spanish Ministries of Education and Science and Economy and Competitiveness under the project Consolider-Ingenio 2010 (CSD2009-00050 "Development of more efficient catalysts for the design of sustainable chemical processes and clean energy production") and the Severo Ochoa program (SEV-2012-0267), respectively. D.C. thanks the Spanish MEC for postgraduate scholarship, project MAT2006-14274-C02-01.Cómbita Merchán, DF.; Concepción Heydorn, P.; Corma Canós, A. (2014). Gold catalysts for the synthesis of aromatic azocompounds from nitroaromatics in one step. Journal of Catalysis. 311:339-349. https://doi.org/10.1016/j.jcat.2013.12.014S33934931
Estimation of Energy Expenditure in Wheelchair-Bound Spinal Cord Injured Individuals Using Inertial Measurement Units
A healthy lifestyle reduces the risk of cardio-vascular disease. As wheelchair-bound individuals with spinal cord injury (SCI) are challenged in their activities, promoting and coaching an active lifestyle is especially relevant. Although there are many commercial activity trackers available for the able-bodied population, including those providing feedback about energy expenditure (EE), activity trackers for the SCI population are largely lacking, or are limited to a small set of activities performed in controlled settings. The aims of the present study were to develop and validate an algorithm based on inertial measurement unit (IMU) data to continuously monitor EE in wheelchair-bound individuals with a SCI, and to establish reference activity values for a healthy lifestyle in this population. For this purpose, EE was measured in 30 subjects each wearing four IMUs during 12 different physical activities, randomly selected from a list of 24 activities of daily living. The proposed algorithm consists of three parts: resting EE estimation based on multi-linear regression, an activity classification using a k-nearest-neighbors algorithm, and EE estimation based on artificial neural networks (ANNs). The mean absolute estimation error for the ANN-based algorithm was 14.4% compared to indirect calorimeter measurements. Based on reference values from the literature and the data collected within this study, we recommend wheeling 3 km per day for a healthy lifestyle in wheelchair-bound SCI individuals. Combining the proposed algorithm with a recommendation for physical activity provides a powerful tool for the promotion of an active lifestyle in the SCI population, thereby reducing the risk for secondary diseases
Rich Pickings Near Large Communal Roosts Favor ‘Gang’ Foraging by Juvenile Common Ravens, Corvus corax
Ravens (Corvus corax) feed primarily on rich but ephemeral carcasses of large animals, which are usually defended by territorial pairs of adults. Non-breeding juveniles forage socially and aggregate in communal winter roosts, and these appear to function as ‘information centers’ regarding the location of the rare food bonanzas: individuals search independently of one another and pool their effort by recruiting each other at roosts. However, at a large raven roost in Newborough on Anglesey, North Wales, some juveniles have been observed recently to forage in ‘gangs’ and to roost separately from other birds. Here we adapt a general model of juvenile common raven foraging behavior where, in addition to the typical co-operative foraging strategy, such gang foraging behavior could be evolutionarily stable near winter raven roosts. We refocus the model on the conditions under which this newly documented, yet theoretically anticipated, gang-based foraging has been observed. In the process, we show formally how the trade off between search efficiency and social opportunity can account for the existence of the alternative social foraging tactics that have been observed in this species. This work serves to highlight a number of fruitful avenues for future research, both from a theoretical and empirical perspective
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