Demonstrative experiments about gold nanoparticles and nanofilms: an introduction to nanoscience

International audienceAn important task of the scientific community is to provide non-specialized audience with explanations about what is nanoscience. Such explanations can be given during public conferences, seminars in high schools or lab work organized with teachers. And very often, the use of an experimental illustration greatly helps to raise the interest and the curiosity of the public. The present article will describe how the authors have used five simple and visual experiments in chemistry and physics to progressively introduce different audiences into the fascination of nanoscience. One experiment is the synthesis of gold nanoparticles with the Turkevich method and shows the progressive appearance of the ruby-red colour of the nanometric gold particles. The second and third experiments describe the way for modulating their colour and how to include them into a polymer and form a ruby-red coloured plastic film. The fourth experiment shows that starting from these nanoparticles, it is possible to turn them back into a yellow golden film. The last experiment is based on the optical properties of ultra-thin gold films. Using the plasmon resonance, it is possible to demonstrate that gold change colours from yellow to orange and green when a white light beam is shone on the gold interface. These visual experiments cannot be fully interpreted in front of a large audience but serve for rising curiosity

An Examination of Standardized Language, Mathematics, and Reading Achievement Testing Results when Compared for Middle School Aged Student Leaders and Non-Student Leaders

The evolution of the middle school concept, according to Forte and Schurr (2003), with its own identity and its subsequent implementation, has proven to be an ideal or preferred model for educating students. Knowles and Brown (2000) assert the importance of middle level teachers\u27 ability to nurture their students\u27 academic, emotional, personal, and social development during the often chaotic years of transescence and early adolescence. This study examined and explored sixty-four randomly selected seventh grade middle school students\u27 earned scores on their annual standardized achievement testing, particularly the Terra Nova II Multiple Assessments subtests in the areas of Language, Mathematics, and Reading. The investigator wanted to determine if demonstrating and applying leadership abilities, competencies, qualities, skills, and traits positively influenced the seventh grade middle school students\u27 earned achievement? Additionally, regardless of the seventh grade middle school students\u27 intelligence quotient (IQ), did their demonstrating leadership abilities, competencies, qualities, skills, and traits positively influence their earned scores on the annual standardized achievement testing, particularly the Terra Nova II Multiple Assessments subtests in the areas of Language, Mathematics, and Reading? The statistical analyses included an analysis of variance (ANOVA), specifically a T test; in addition, an F test was subsequently calculated to determine any significant interactions. The findings of this study were explored and discussed from Freed and Parsons (1997) view of the left-right brain continuum, as two of the three main effect hypotheses were rejected. As a result, the findings yielded a significant difference in student leaders and non-student leaders\u27 earned achievement test scores on the subtests of Language and Reading on the Terra Nova II Multiple Assessments. This investigator suggests that the left-right brain continuum theory is a potential, valid, and research-supported variable in this study, as it elucidates students\u27 learning styles. Moreover, it is widely stated and commonly known that learning styles ultimately effect students\u27 achievement and earned scores on both standardized testing and authentic assessments. Finally, the results of this study can assist professional guidance counselors, as well as school district administrators and faculty who are considering implementation and germination of such student leadership programs in their middle school curriculum

Jacques Thuillier : hommage à un bienfaiteur de la Moselle et de la Lorraine

Communications de l'Année Académique 2015-201

PREDON Scientific Data Preservation 2014

LPSC14037Scientific data collected with modern sensors or dedicated detectors exceed very often the perimeter of the initial scientific design. These data are obtained more and more frequently with large material and human efforts. A large class of scientific experiments are in fact unique because of their large scale, with very small chances to be repeated and to superseded by new experiments in the same domain: for instance high energy physics and astrophysics experiments involve multi-annual developments and a simple duplication of efforts in order to reproduce old data is simply not affordable. Other scientific experiments are in fact unique by nature: earth science, medical sciences etc. since the collected data is "time-stamped" and thereby non-reproducible by new experiments or observations. In addition, scientific data collection increased dramatically in the recent years, participating to the so-called "data deluge" and inviting for common reflection in the context of "big data" investigations. The new knowledge obtained using these data should be preserved long term such that the access and the re-use are made possible and lead to an enhancement of the initial investment. Data observatories, based on open access policies and coupled with multi-disciplinary techniques for indexing and mining may lead to truly new paradigms in science. It is therefore of outmost importance to pursue a coherent and vigorous approach to preserve the scientific data at long term. The preservation remains nevertheless a challenge due to the complexity of the data structure, the fragility of the custom-made software environments as well as the lack of rigorous approaches in workflows and algorithms. To address this challenge, the PREDON project has been initiated in France in 2012 within the MASTODONS program: a Big Data scientific challenge, initiated and supported by the Interdisciplinary Mission of the National Centre for Scientific Research (CNRS). PREDON is a study group formed by researchers from different disciplines and institutes. Several meetings and workshops lead to a rich exchange in ideas, paradigms and methods. The present document includes contributions of the participants to the PREDON Study Group, as well as invited papers, related to the scientific case, methodology and technology. This document should be read as a "facts finding" resource pointing to a concrete and significant scientific interest for long term research data preservation, as well as to cutting edge methods and technologies to achieve this goal. A sustained, coherent and long term action in the area of scientific data preservation would be highly beneficial

A simple standard technique for labyrinthectomy in the rat: A methodical communication with a detailed description of the surgical process

Aims: Labyrinthectomized rats are suitable models to test consequences of vestibular lesion and are widely used to study neural plasticity. We describe a combined microsurgical–chemical technique that can be routinely performed with minimum damage. Methods Caudal leaflet of the parotis is elevated. The tendinous fascia covering the bulla is opened frontally from the sternomastoid muscle’s tendon while sparing facial nerve branches. A 4 mm diameter hole is drilled into the bulla’s hind lower lateral wall to open the common (in rodents) mastoid-tympanic cavity. The cochlear crista (promontory) at the lower posterior part of its medial wall is identified as a bony prominence. A 1 mm diameter hole is drilled into its lower part. The perilymphatic/endolymphatic fluids with tissue debris of the Corti organ are suctioned. Ethanol is injected into the hole. Finally, 10 µL of sodium arsenite solution (50 µM/mL) is pumped into the labyrinth and left in place for 15 min. Simple closure in two layers (fascia and skin) is sufficient. Results and conclusion All rats had neurological symptoms specific for labyrinthectomy (muscle tone, body position, rotatory movements, nystagmus, central deafness). Otherwise, their behavior was unaffected, drinking and eating normally. After a few days, they learned to balance relying on visual and somatic stimuli (neuroplasticity)

Dawson-type polyoxometalates photosensitized with carbon dots for photocatalytic reduction of silver ions

Carbon dots (CDs) are carbon-based nanoparticles (NPs) displaying remarkable light-harvesting properties. In this work, we have investigated for the first time the possibility to use CDs to photosensitize polyoxometalates (POMs). For this purpose, we have thus engineered positively charged carbon dots allowing electrostatic interactions with anionic Dawson-type POMs. Following the formation of these new POM-CDs complexes, an efficient photoinduced electron transfer between photoexcited CDs and POMs allows the reduced POM to perform reduction reactions. The reduction of silver ions into silver nanoparticles (AgNPs) has been chosen as a model reaction

Wiring of Photosystem II to Hydrogenase for Photoelectrochemical Water Splitting.

In natural photosynthesis, light is used for the production of chemical energy carriers to fuel biological activity. The re-engineering of natural photosynthetic pathways can provide inspiration for sustainable fuel production and insights for understanding the process itself. Here, we employ a semiartificial approach to study photobiological water splitting via a pathway unavailable to nature: the direct coupling of the water oxidation enzyme, photosystem II, to the H2 evolving enzyme, hydrogenase. Essential to this approach is the integration of the isolated enzymes into the artificial circuit of a photoelectrochemical cell. We therefore developed a tailor-made hierarchically structured indium-tin oxide electrode that gives rise to the excellent integration of both photosystem II and hydrogenase for performing the anodic and cathodic half-reactions, respectively. When connected together with the aid of an applied bias, the semiartificial cell demonstrated quantitative electron flow from photosystem II to the hydrogenase with the production of H2 and O2 being in the expected two-to-one ratio and a light-to-hydrogen conversion efficiency of 5.4% under low-intensity red-light irradiation. We thereby demonstrate efficient light-driven water splitting using a pathway inaccessible to biology and report on a widely applicable in vitro platform for the controlled coupling of enzymatic redox processes to meaningfully study photocatalytic reactions.This work was supported by the U.K. Engineering and Physical Sciences Research Council (EP/H00338X/2 to E.R. and EP/G037221/1, nanoDTC, to D.M.), the UK Biology and Biotechnological Sciences Research Council (BB/K002627/1 to A.W.R. and BB/K010220/1 to E.R.), a Marie Curie Intra-European Fellowship (PIEF-GA-2013-625034 to C.Y.L), a Marie Curie International Incoming Fellowship (PIIF-GA-2012-328085 RPSII to J.J.Z) and the CEA and the CNRS (to J.C.F.C.). A.W.R. holds a Wolfson Merit Award from the Royal Society.This is the final version of the article. It first appeared from ACS Publications via http://dx.doi.org/10.1021/jacs.5b0373