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

The Spared Nerve Injury (SNI) Model of Induced Mechanical Allodynia in Mice

Peripheral neuropathic pain is a severe chronic pain condition which may result from trauma to sensory nerves in the peripheral nervous system. The spared nerve injury (SNI) model induces symptoms of neuropathic pain such as mechanical allodynia i.e. pain due to tactile stimuli that do not normally provoke a painful response [1]

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

Cellular and humoral immunity protect against vaginal Zika virus infection in mice

ABSTRACT Zika virus (ZIKV), which can cause devastating disease in fetuses of infected pregnant women, can be transmitted by mosquito inoculation and sexual routes. Little is known about immune protection against sexually transmitted ZIKV. In this study, we show that previous infection through intravaginal or subcutaneous routes with a contemporary Brazilian strain of ZIKV can protect against subsequent intravaginal challenge with a homologous strain. Both routes of inoculation induced high titers of ZIKV-specific and neutralizing antibody in serum and the vaginal lumen. Virus-specific T cells were recruited to and retained in the female reproductive tract after intravaginal and subcutaneous ZIKV infection. Studies in mice with genetic or acquired deficiencies in B and/or T cells demonstrated that both lymphocyte populations redundantly protect against intravaginal challenge in ZIKV-immune animals. Passive transfer of ZIKV-immune IgG or T cells significantly limited intravaginal infection of naive mice, although antibody more effectively prevented dissemination throughout the reproductive tract. Collectively, our experiments begin to establish the immune correlates of protection against intravaginal ZIKV infection, which should inform vaccination strategies in nonpregnant and pregnant women. IMPORTANCE The recent ZIKV epidemic resulted in devastating outcomes in fetuses and may affect reproductive health. Unlike other flaviviruses, ZIKV can be spread by sexual contact as well as a mosquito vector. While previous studies have identified correlates of protection for mosquito-mediated infection, few have focused on immunity against sexual transmission. As exposure to ZIKV via mosquito bite has likely occurred to many living in areas where ZIKV is endemic, our study addresses whether this route of infection can protect against subsequent sexual exposure. We demonstrate that subcutaneous ZIKV infection can protect against subsequent vaginal infection by generating both local antiviral T cell and antibody responses. Our research begins to define the immune correlates of protection for ZIKV infection in the vagina and provides a foundation for testing ZIKV vaccines against sexual transmission. </jats:p

Offspring social network structure predicts fitness in families.

addresses: Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9EZ, UK. [email protected]: PMCID: PMC3497231types: Journal Article; Research Support, Non-U.S. Gov'tSocial structures such as families emerge as outcomes of behavioural interactions among individuals, and can evolve over time if families with particular types of social structures tend to leave more individuals in subsequent generations. The social behaviour of interacting individuals is typically analysed as a series of multiple dyadic (pair-wise) interactions, rather than a network of interactions among multiple individuals. However, in species where parents feed dependant young, interactions within families nearly always involve more than two individuals simultaneously. Such social networks of interactions at least partly reflect conflicts of interest over the provision of costly parental investment. Consequently, variation in family network structure reflects variation in how conflicts of interest are resolved among family members. Despite its importance in understanding the evolution of emergent properties of social organization such as family life and cooperation, nothing is currently known about how selection acts on the structure of social networks. Here, we show that the social network structure of broods of begging nestling great tits Parus major predicts fitness in families. Although selection at the level of the individual favours large nestlings, selection at the level of the kin-group primarily favours families that resolve conflicts most effectively

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

Voltage Biasing, Cyclic Voltammetry, & Electrical Impedance Spectroscopy for Neural Interfaces

Electrical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measure properties of the electrode-tissue interface without additional invasive procedures, and can be used to monitor electrode performance over the long term. EIS measures electrical impedance at multiple frequencies, and increases in impedance indicate increased glial scar formation around the device, while cyclic voltammetry measures the charge carrying capacity of the electrode, and indicates how charge is transferred at different voltage levels. As implanted electrodes age, EIS and CV data change, and electrode sites that previously recorded spiking neurons often exhibit significantly lower efficacy for neural recording. The application of a brief voltage pulse to implanted electrode arrays, known as rejuvenation, can bring back spiking activity on otherwise silent electrode sites for a period of time. Rejuvenation alters EIS and CV, and can be monitored by these complementary methods. Typically, EIS is measured daily as an indication of the tissue response at the electrode site. If spikes are absent in a channel that previously had spikes, then CV is used to determine the charge carrying capacity of the electrode site, and rejuvenation can be applied to improve the interface efficacy. CV and EIS are then repeated to check the changes at the electrode-tissue interface, and neural recordings are collected. The overall goal of rejuvenation is to extend the functional lifetime of implanted arrays

LONGO: An R package for interactive gene length dependent analysis for neuronal identity

Motivation: Reprogramming somatic cells into neurons holds great promise to model neuronal development and disease. The efficiency and success rate of neuronal reprogramming, however, may vary between different conversion platforms and cell types, thereby necessitating an unbiased, systematic approach to estimate neuronal identity of converted cells. Recent studies have demonstrated that long genes (\u3e100 kb from transcription start to end) are highly enriched in neurons, which provides an opportunity to identify neurons based on the expression of these long genes. Results: We have developed a versatile R package, LONGO, to analyze gene expression based on gene length. We propose a systematic analysis of long gene expression (LGE) with a metric termed the long gene quotient (LQ) that quantifies LGE in RNA-seq or microarray data to validate neuronal identity at the single-cell and population levels. This unique feature of neurons provides an opportunity to utilize measurements of LGE in transcriptome data to quickly and easily distinguish neurons from non-neuronal cells. By combining this conceptual advancement and statistical tool in a user-friendly and interactive software package, we intend to encourage and simplify further investigation into LGE, particularly as it applies to validating and improving neuronal differentiation and reprogramming methodologies. Availability and implementation: LONGO is freely available for download at https://github.com/biohpc/longo. Supplementary information: Supplementary data are available at Bioinformatics online