SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Imprint

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The ability to identify and retain logical relations between stimuli and apply them to novel stimuli is known as relational concept learning. This has been demonstrated in a few animal species after extensive reinforcement training, and it reveals the brain’s ability to deal with abstract properties. Here we describe relational concept learning in newborn ducklings without reinforced training. Newly hatched domesticated mallards that were briefly exposed to a pair of objects that were either the same or different in shape or color later preferred to follow pairs of new objects exhibiting the imprinted relation. Thus, even in a seemingly rigid and very rapid form of learning such as filial imprinting, the brain operates with abstract conceptual reasoning, a faculty often assumed to be reserved to highly intelligent organisms.

Concepts: Imprint, Logic, Object, Abstraction, Learning, Imprinting, Cognition

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One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the ‘campanile’ near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub <100 nm position accuracy, followed by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.

Concepts: Nanoimprint lithography, Lithography, Ultraviolet, Optical fiber, Optics, Imprint, Micrograph, Scanning electron microscope

36

Debates over the pros and cons of a “publish or perish” philosophy have inflamed academia for at least half a century. Growing concerns, in particular, are expressed for policies that reward “quantity” at the expense of “quality,” because these might prompt scientists to unduly multiply their publications by fractioning (“salami slicing”), duplicating, rushing, simplifying, or even fabricating their results. To assess the reasonableness of these concerns, we analyzed publication patterns of over 40,000 researchers that, between the years 1900 and 2013, have published two or more papers within 15 years, in any of the disciplines covered by the Web of Science. The total number of papers published by researchers during their early career period (first fifteen years) has increased in recent decades, but so has their average number of co-authors. If we take the latter factor into account, by measuring productivity fractionally or by only counting papers published as first author, we observe no increase in productivity throughout the century. Even after the 1980s, adjusted productivity has not increased for most disciplines and countries. These results are robust to methodological choices and are actually conservative with respect to the hypothesis that publication rates are growing. Therefore, the widespread belief that pressures to publish are causing the scientific literature to be flooded with salami-sliced, trivial, incomplete, duplicated, plagiarized and false results is likely to be incorrect or at least exaggerated.

Concepts: Tenure, Imprint, Literature, Science, Publication, Publishing, Scientific method, Academic publishing

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Molecular genetic testing for the 11p15-associated imprinting disorders Silver-Russell and Beckwith-Wiedemann syndrome (SRS, BWS) is challenging because of the molecular heterogeneity and complexity of the affected imprinted regions. With the growing knowledge on the molecular basis of these disorders and the demand for molecular testing, it turned out that there is an urgent need for a standardized molecular diagnostic testing and reporting strategy. Based on the results from the first external pilot quality assessment schemes organized by the European Molecular Quality Network (EMQN) in 2014 and in context with activities of the European Network of Imprinting Disorders (EUCID.net) towards a consensus in diagnostics and management of SRS and BWS, best practice guidelines have now been developed. Members of institutions working in the field of SRS and BWS diagnostics were invited to comment, and in the light of their feedback amendments were made. The final document was ratified in the course of an EMQN best practice guideline meeting and is in accordance with the general SRS and BWS consensus guidelines, which are in preparation. These guidelines are based on the knowledge acquired from peer-reviewed and published data, as well as observations of the authors in their practice. However, these guidelines can only provide a snapshot of current knowledge at the time of manuscript submission and readers are advised to keep up with the literature.European Journal of Human Genetics advance online publication, 11 May 2016; doi:10.1038/ejhg.2016.45.

Concepts: Scientific method, Imprint, Quality assurance, H19, Human genome, Best practice, Management, Genetics

1

This month, to celebrate a quarter century of excellence in genetics, we are highlighting selections from the past work we have published. We will then publish a number of forward-looking Perspectives in the coming months to examine and chart the future directions of our field. In parallel, we will also consult researchers for their answers to current questions of interest to the genetics and genomics community for discussion throughout the year.

Concepts: Publishing, Jennifer Warnes, Present, Academic publishing, Imprint, Past, Time, Future

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Pseudouridine (Ψ) is an important urinary cancer biomarker, especially in human colorectal cancer (CRC). Disclosed herein is the first Ψ molecularly imprinted polymer (Ψ-MIP) material obtained from tailor-engineered functional monomers. The resulting MIP imprint exhibits a remarkable imprinting factor greater than 70. It is successfully used for the selective recognition of Ψ in spiked human urine. This selective functionalized material opens the route to the development of inexpensive disposable chemosensors for noninvasive CRC diagnosis and prognosis.

Concepts: Colorectal cancer, Urine, Cancer, Imprint

0

Magnetic molecularly imprinted polymer nanoparticles for bisphenol A were prepared by coassembling magnetic nanoparticles and amphiphilic random copolymers. Under optimized conditions, bisphenol A as template molecules, magnetic molecularly imprinted polymer particles with regular morphology, small size, good monodispersity and high content of OA-Fe3 O4 were prepared by the coassembly method using P(MMA-co-MAA) with monomer ratio of 9:1. These magnetic molecularly imprinted polymer particles could be rapidly collected by an external magnet within 1 min. The saturated adsorption capacity of the magnetic molecularly imprinted polymer for bisphenol A was 201.5 mg/g, and the imprinting factor was 2.5. The separation factors for bisphenol A to β-estradiol, estriol and diethylstilbestrol was 3.1, 2.9 and 3.7, respectively. Unlike assembling amphiphilic copolymer in the selective solvent, the coassembly process was simple and rapid. Therefore, the present work provided a facile and versatile approach to construct magnetic molecularly imprinted polymer nanoparticles under mild conditions. This article is protected by copyright. All rights reserved.

Concepts: Magnetic field, Imprint, Magnetism, Copolymer, All rights reserved, Copyright, Polymer, Polymer chemistry

0

Experiences during early development can influence neuronal functions and modulate adult behaviors [1, 2]. However, the molecular mechanisms underlying the long-term behavioral effects of these early experiences are not fully understood. The C. elegans ascr#3 (asc-ΔC9; C9) pheromone triggers avoidance behavior in adult hermaphrodites [3-7]. Here, we show that hermaphrodites that are briefly exposed to ascr#3 immediately after birth exhibit increased ascr#3-specific avoidance as adults, indicating that ascr#3-experienced animals form a long-lasting memory or imprint of this early ascr#3 exposure [8]. ascr#3 imprinting is mediated by increased synaptic activity between the ascr#3-sensing ADL neurons and their post-synaptic SMB motor neuron partners via increased expression of the odr-2 glycosylated phosphatidylinositol (GPI)-linked signaling gene in the SMB neurons. Our study suggests that the memory for early ascr#3 experience is imprinted via alteration of activity of a single synaptic connection, which in turn shapes experience-dependent plasticity in adult ascr#3 responses.

Concepts: Imprint, Nervous system, Behavior, Chemical synapse, Spinal cord, Psychology, Neuron, Action potential

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Herein we describe the preparation of molecularly imprinted silica nanoparticles by Ostwald ripening in the presence of molecular templates immobilised on glass beads (the solid-phase). To achieve this, a seed material (12 nm diameter silica nanoparticles) was incubated in phosphate buffer in the presence of the solid-phase. Phosphate ions act as a catalyst in the ripening process which is driven by differences in surface energy between particles of different size, leading to the preferential growth of larger particles. Material deposited in the vicinity of template molecules results in the formation of sol-gel molecular imprints after around 2 hours. Selective washing and elution allows the higher affinity nanoparticles to be isolated. Unlike other strategies commonly used to prepare imprinted silica nanoparticles this approach is extremely simple in nature and can be performed under physiological conditions, making it suitable for imprinting whole proteins and other biomacromolecules in their native conformations. We have demonstrated the generic nature of this method by preparing imprinted silica nanoparticles against targets of varying molecular mass (melamine, vancomycin and trypsin). Binding to the imprinted particles was demonstrated in an immunoassay (ELISA) format in buffer and complex media (milk or blood plasma) with sub-nM detection ability.

Concepts: Chemical bond, DNA, Colloid, Nanoparticle, Imprint, Glass, Sol-gel, Molecule

0

A surface-grafted imprinted ceramic membrane (IIP-PVI/CM) for recognizing molybdate (Mo(VI)) anion was prepared by surface-initiated graft-polymerization. Firstly, raw alumina ceramic membrane (CM) was deposited with SiO2 active layer by situ hydrolysis deposition method. Subsequently, γ-methacryloxy propyl trimethoxyl silane (MPS) was used as a coupling agent to introduce double bonds onto the SiO2 layer (MPS-CM). Then, 1-vinylimidazole (VI) was employed as a functional monomer to graft-polymerization onto the MPS-CM (PVI-CM). During the graft-polymerization, the influence factors of grafting degree of PVI were investigated in detail. Under optimum conditions (monomer concentration 20wt%, temperature 70°C, initiator amount 1.1wt% and reaction time 8h), the grafting degree of 20.39g/100g was obtained. Further, Mo(VI) anion was used as a template to imprint in the PVI-CM by employing 1,6-dibromohexane as a cross-linking agent, and then Mo(VI) was removed, obtaining the IIP-PVI/CM with many imprinted cavities for Mo(VI). Thereafter, static adsorption and dynamic separation properties of IIP-PVI/CM for Mo(VI) were studied. Results indicate that IIP-PVI/CM shows a specific selectivity for Mo(VI) with the adsorption capacity of 0.69mmol/100g, and the selectivity coefficient of IIP-PVI/CM is 7.48 for molybdate to tungstate anions. During the dynamic separation, IIP-PVI/CM has also good selectivity for separation of Mo(VI) and W(VI) anions.

Concepts: Imprint, Aluminium oxide, Ion, Atom, Electron, Ionic bond, Solid, Polymer chemistry