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Sample records for bioactifs nanostructures elabores

  1. Plasma-based ion implantation: a valuable technology for the elaboration of innovative materials and nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Vempaire, D.; Pelletier, J.; Lacoste, A.; Béchu, S.; Sirou, J.; Miraglia, S.; Fruchart, D.

    2005-05-01

    Plasma-based ion implantation (PBII), invented in 1987, can now be considered as a mature technology for thin film modification. After a brief recapitulation of the principle and physics of PBII, its advantages and disadvantages, as compared to conventional ion beam implantation, are listed and discussed. The elaboration of thin films and the modification of their functional properties by PBII have already been achieved in many fields, such as microelectronics (plasma doping/PLAD), biomaterials (surgical implants, bio- and blood-compatible materials), plastics (grafting, surface adhesion) and metallurgy (hard coatings, tribology), to name a few. The major advantages of PBII processing lie, on the one hand, in its flexibility in terms of ion implantation energy (from 0 to 100 keV) and operating conditions (plasma density, collisional or non-collisional ion sheath), and, on the other hand, in the easy transferrability of processes from the laboratory to industry. The possibility of modifying the composition and physical nature of the films, or of drastically changing their physical properties over several orders of magnitude makes this technology very attractive for the elaboration of innovative materials, including metastable materials, and the realization of micro- or nanostructures. A review of the state of the art in these domains is presented and illustrated through a few selected examples. The perspectives opened up by PBII processing, as well as its limitations, are discussed.

  2. Structural Study of SiC Nanoparticles Grown by Inductively Coupled Plasma and Laser Pyrolysis for Nano-structured Ceramics Elaboration

    SciTech Connect

    Leconte, Yann; Portier, Xavier; Herlin-Boime, Nathalie; Reynaud, Cecile

    2008-07-01

    Refractory carbide nano-structured ceramics as SiC constitute interesting materials for high temperature applications and particularly for fourth generation nuclear plants. To elaborate such nano-materials, weighable amounts of SiC nano-powders have to be synthesized first with an accurate control of the grain size and stoichiometry. The inductively coupled plasma and the laser pyrolysis techniques, respectively developed at EMPA Thun and CEA Saclay, allow meeting these requirements. Both techniques are able to produce dozens of grams per hour of silicon carbide nano-powders. The particle size can be adjusted down to around 20 nm for the plasma synthesis and even down to 5-10 nm for the laser pyrolysis. The stoichiometry Si/C can be tuned by the addition of methane into the plasma and acetylene for the laser process. (authors)

  3. New nanostructured carbons based on porous cellulose: Elaboration, pyrolysis and use as platinum nanoparticles substrate for oxygen reduction electrocatalysis

    NASA Astrophysics Data System (ADS)

    Guilminot, Elodie; Gavillon, Roxane; Chatenet, Marian; Berthon-Fabry, Sandrine; Rigacci, Arnaud; Budtova, Tatiana

    New nanostructured carbons have been prepared from pyrolysis of recently developed highly porous cellulose, aerocellulose (AC). Aerocellulose is an ultra-light and highly porous pure cellulose material prepared from cellulose gels followed by drying in carbon dioxide supercritical conditions. The carbonized aerocellulose (CAC) materials were obtained after pyrolysis of the aerocellulose under nitrogen flow at 830 °C, and subsequently doped by platinum nanoparticles. The platinum insertion process consisted of (i) thermal activation at various temperatures in CO 2 atmosphere, (ii) impregnation by PtCl 6 2- and (iii) platinum salt chemical reduction. The aerocellulose materials and their carbonized counterparts were investigated by scanning and transmission electron microscopy (SEM and TEM), mercury porosimetry and thermogravimetric analysis. The morphology of the platinum particles deposited on the carbonized aerocellulose materials (Pt/CAC) was investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD): the Pt particles are of 4-5 nm size, mainly agglomerated, as a result of the complex surface chemistry of the CAC. Their electrocatalytic activity was investigated by quasi-steady-state voltammetry in the rotating disk electrode (RDE) setup, regarding the oxygen reduction reaction (ORR). The Pt/CAC materials exhibit ORR specific activities comparable with those of commercial Pt/Vulcan XC72R. Their mass activity is lower, as a result of the ca. 10 times smaller specific area of platinum as compared with the commercial electrocatalyst. We nevertheless believe that provided an appropriate pyrolysis temperature is chosen, such green carbonized aerocellulose could be a promising electrocatalyst support for PEM application.

  4. Characteristics of nanostructured Zn1-xVxO thin films with high vanadium content elaborated by rf-magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Medjnoun, K.; Djessas, K.; Belkaid, M. S.; Grillo, S. E.; Solhy, A.; Briot, O.; Moret, M.

    2015-06-01

    Nanostructured Zn1-xVxO (0 ⩽ x ⩽ 0.50) thin films were synthesized by rf-magnetron sputtering at two different substrate temperatures (room temperature (RT) and 200 °C) and with variable sputtering powers (60, 80 and 100 W). In this method, single targets based on Zn1-xVxO nanopowders prepared by the sol-gel process were used. Characterization of the Zn1-xVxO nanoparticles showed that they crystallize in the hexagonal wurtzite structure. Their size ranged from 20 to 40 nm. The effect of process parameters on the physical and chemical properties of Zn1-xVxO thin films has been studied. For x ⩽ 0.30, the results obtained at 200 °C and 60 W indicate that the films have a high quality of crystallinity. Vegard's law is respected, indicating that vanadium is incorporated in the ZnO matrix. The chemical compositions of these films were found to be close to the stoichiometry. The films exhibit a columnar structure and a smooth surface. Their average transmission, from the visible to the NIR, was in the range of 75-90%. The values of the band gap of the Zn1-xVxO thin films with x ⩽ 0.30 and elaborated at 200 °C and 60 W, vary from 3.29 to 3.74 eV. This is consistent with blue shifting of near-band edge cathodoluminescence emission. Under particular growth conditions, the investigation shows that the Zn0.80V0.20O sample presents the best properties for potential use in various optoelectronic applications, namely: a single wurtzite phase, low surface roughness (Ra ∼ 0.2 nm), a high transparency of 90% in the UV-Vis-NIR, a wide band gap of 3.74 eV and a resistivity of ∼5 × 10+3 Ω cm.

  5. Elaborating on Threshold Concepts

    ERIC Educational Resources Information Center

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-01-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

  6. Elaborating on threshold concepts

    NASA Astrophysics Data System (ADS)

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-09-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account for both the important and the problematic characteristics of TCs in terms of the Knowledge/Strategies/Mental Models Framework defined in previous work.

  7. Orangutan pantomime: elaborating the message

    PubMed Central

    Russon, Anne; Andrews, Kristin

    2011-01-01

    We present an exploratory study of forest-living orangutan pantomiming, i.e. gesturing in which they act out their meaning, focusing on its occurrence, communicative functions, and complexities. Studies show that captive great apes may elaborate messages if communication fails, and isolated reports suggest that great apes occasionally pantomime. We predicted forest-living orangutans would pantomime spontaneously to communicate, especially to elaborate after communication failures. Mining existing databases on free-ranging rehabilitant orangutans' behaviour identified 18 salient pantomimes. These pantomimes most often functioned as elaborations of failed requests, but also as deceptions and declaratives. Complexities identified include multimodality, re-enactments of past events and several features of language (productivity, compositionality, systematicity). These findings confirm that free-ranging rehabilitant orangutans pantomime and use pantomime to elaborate on their messages. Further, they use pantomime for multiple functions and create complex pantomimes that can express propositionally structured content. Thus, orangutan pantomime serves as a medium for communication, not a particular function. Mining cases of complex great ape communication originally reported in functional terms may then yield more evidence of pantomime. PMID:20702451

  8. Example Elaboration as a Neglected Instructional Strategy

    SciTech Connect

    Girill, T R

    2001-07-18

    Over the last decade an unfolding cognitive-psychology research program on how learners use examples to develop effective problem solving expertise has yielded well-established empirical findings. Chi et al., Renkl, Reimann, and Neubert (in various papers) have confirmed statistically significant differences in how good and poor learners inferentially elaborate (self explain) example steps as they study. Such example elaboration is highly relevant to software documentation and training, yet largely neglected in the current literature. This paper summarizes the neglected research on example use and puts its neglect in a disciplinary perspective. The author then shows that differences in support for example elaboration in commercial software documentation reveal previously over looked usability issues. These issues involve example summaries, using goals and goal structures to reinforce example elaborations, and prompting readers to recognize the role of example parts. Secondly, I show how these same example elaboration techniques can build cognitive maturity among underperforming high school students who study technical writing. Principle based elaborations, condition elaborations, and role recognition of example steps all have their place in innovative, high school level, technical writing exercises, and all promote far transfer problem solving. Finally, I use these studies to clarify the constructivist debate over what writers and readers contribute to text meaning. I argue that writers can influence how readers elaborate on examples, and that because of the great empirical differences in example study effectiveness (and reader choices) writers should do what they can (through within text design features) to encourage readers to elaborate examples in the most successful ways. Example elaboration is a uniquely effective way to learn from worked technical examples. This paper summarizes years of research that clarifies example elaboration. I then show how example

  9. Conditions and Effects of Example Elaboration.

    ERIC Educational Resources Information Center

    Stark, Robin; Mandl, Heinz; Gruber, Hans; Renkl, Alexander

    2002-01-01

    Reanalyzed findings of an earlier study on learning with worked-out examples (n=56 vocational school students) and identified different ways of dealing with worked-out examples and related them to learning outcomes and learners' mental efforts. Results show that elaboration training had a positive effect on the quality of example elaboration.…

  10. Multiple Strand Sequencing Using the Elaboration Theory.

    ERIC Educational Resources Information Center

    Beissner, Katherine; Reigeluth, Charles M.

    This study examined the sequencing of instruction in a course in physical therapy. In the first phase, a procedural elaboration sequence was designed using the Simplifying Assumptions Method. In the second phase, a prescriptive-theoretical elaboration sequence independent of the procedural sequence was designed. A descriptive-theoretical…

  11. Constructing specifications by combining parallel elaborations

    SciTech Connect

    Feather, M.S.

    1989-02-01

    Constructing specifications of complex tasks is often a laborious activity in spite of the rich vocabulary provided by specification languages. An incremental approach to construction is proposed, with the virtue of offering considerable opportunity for mechanized support. Following this approach one builds a specification through a series of elaborations that incrementally adjust a simple initial specification. Elaborations perform both refinements, adding further detail, and adaptations, retracting oversimplifications and tailoring approximations to the specifics of the task. It is anticipated that the vast majority of elaborations can be concisely described to a mechanism which will then perform them automatically. When elaborations are independent, they can be applied in parallel, leading to diverging specifications which must later be recombined. The approach is intended to facilitate comprehension and maintenance of specifications, as well as their initial construction. The advantages of following this approach stem from the gradual nature of the elaboration process, the separation of concerns through following independent elaborations in parallel, the simplicity of the individual elaboration steps (the effects of each step are well delineated), and the availability of an explicit record of construction.

  12. REMARK checklist elaborated to improve tumor prognostician

    Cancer.gov

    Experts have elaborated on a previously published checklist of 20 items -- including descriptions of design, methods, and analysis -- that researchers should address when publishing studies of prognostic markers. These markers are indicators that enable d

  13. Superhydrophilic nanostructure

    DOEpatents

    Mao, Samuel S; Zormpa, Vasileia; Chen, Xiaobo

    2015-05-12

    An embodiment of a superhydrophilic nanostructure includes nanoparticles. The nanoparticles are formed into porous clusters. The porous clusters are formed into aggregate clusters. An embodiment of an article of manufacture includes the superhydrophilic nanostructure on a substrate. An embodiment of a method of fabricating a superhydrophilic nanostructure includes applying a solution that includes nanoparticles to a substrate. The substrate is heated to form aggregate clusters of porous clusters of the nanoparticles.

  14. Mental Effort and Elaboration: A Developmental Analysis.

    ERIC Educational Resources Information Center

    Kee, Daniel W.; Davies, Leslie

    1988-01-01

    Dual task procedures (finger tapping and associative memory) were used to examine developmental differences in the amount of mental effort required to deploy rehearsal and elaboration. Sixth-grade and college students participated. Some evidence for a developmental difference in mental effort was found. (TJH)

  15. Teaching Mathematical Modelling: Demonstrating Enrichment and Elaboration

    ERIC Educational Resources Information Center

    Warwick, Jon

    2015-01-01

    This paper uses a series of models to illustrate one of the fundamental processes of model building--that of enrichment and elaboration. The paper describes how a problem context is given which allows a series of models to be developed from a simple initial model using a queuing theory framework. The process encourages students to think about the…

  16. [Elaboration and critical evaluation of clinical guidelines].

    PubMed

    García Villar, C

    2015-11-01

    Clinical guidelines are documents to help professionals and patients select the best diagnostic or therapeutic option. Elaborating guidelines requires an efficient literature search and a critical evaluation of the articles found to select the most appropriate ones. After that, the recommendations are formulated and then must be externally evaluated before they can be disseminated. Even when the guidelines are very thorough and rigorous, it is important to know whether they fulfill all the methodological requisites before applying them. With this aim, various scales have been developed to critically appraise guidelines. Of these, the AGREE II instrument is currently the most widely used. This article explains the main steps in elaborating clinical guidelines and the main aspects that should be analyzed to know whether the guidelines are well written. PMID:26545328

  17. Simple perineal and elaborated perineal posterior urethroplasty

    PubMed Central

    Webster, George D.; Peterson, Andrew C.

    2015-01-01

    A pelvic fracture urethral distraction defect (PFUDD) can present in varying lengths and degrees of complexity. In recent decades the repair of PFUDD has developed into a reliance on a perineal anastomotic approach for all but the most complex cases, which might still require an abdominal transpubic approach, or rarely a staged skin-inlay procedure. There is now controversy about the extent to which the perineal repair needs to be elaborated in individual patients. As originally described, the elaborated perineal approach comprises four steps that are used sequentially, as required, depending on the magnitude of the urethral defect. These steps are urethral mobilisation, corporal body separation, inferior wedge pubectomy and supra-crural urethral re-routing to the anastomosis. We present a review of the progressive repair, its reported use and outcomes and our recommendations for its continued use. PMID:26019973

  18. Elaboration of a water ichtyologic potential index.

    PubMed

    Dehavay, P; Boelen, C

    1992-04-01

    A model has been developed, using physico-chemical data, in order to quantify the quality of surface waters and their ichtyologic potential: the WIPI model (Water Ichtyologic Potential Index). Many physico-chemical parameters, useless if considered individually, can be of practical interest for pisciculture (e.g., an explanation of systematic fish mortalities, elaboration of guidelines for new pisciculture). The water quality is expressed in terms of an eight-step scale that provides a guide evaluation of the ichtyologic potential. PMID:1594921

  19. False Memories for Suggestions: The Impact of Conceptual Elaboration

    PubMed Central

    Zaragoza, Maria S.; Mitchell, Karen J.; Payment, Kristie; Drivdahl, Sarah

    2010-01-01

    Relatively little attention has been paid to the potential role that reflecting on the meaning and implications of suggested events (i.e., conceptual elaboration) might play in promoting the creation of false memories. Two experiments assessed whether encouraging repeated conceptual elaboration, would, like perceptual elaboration, increase false memory for suggested events. Results showed that conceptual elaboration of suggested events more often resulted in high confidence false memories (Experiment 1) and false memories that were accompanied by the phenomenal experience of remembering them (Experiment 2) than did surface-level processing. Moreover, conceptual elaboration consistently led to higher rates of false memory than did perceptual elaboration. The false memory effects that resulted from conceptual elaboration were highly dependent on the organization of the postevent interview questions, such that conceptual elaboration only increased false memory beyond surface level processing when participants evaluated both true and suggested information in relation to the same theme or dimension. PMID:21103451

  20. What Matters in Scientific Explanations: Effects of Elaboration and Content

    PubMed Central

    Rottman, Benjamin M.; Keil, Frank C.

    2011-01-01

    Given the breadth and depth of available information, determining which components of an explanation are most important is a crucial process for simplifying learning. Three experiments tested whether people believe that components of an explanation with more elaboration are more important. In Experiment 1, participants read separate and unstructured components that comprised explanations of real-world scientific phenomena, rated the components on their importance for understanding the explanations, and drew graphs depicting which components elaborated on which other components. Participants gave higher importance scores for components that they judged to be elaborated upon by other components. Experiment 2 demonstrated that experimentally increasing the amount of elaboration of a component increased the perceived importance of the elaborated component. Furthermore, Experiment 3 demonstrated that elaboration increases the importance of the elaborated information by providing insight into understanding the elaborated information; information that was too technical to provide insight into the elaborated component did not increase the importance of the elaborated component. While learning an explanation, people piece together the structure of elaboration relationships between components and use the insight provided by elaboration to identify important components. PMID:21924709

  1. False Memories for Suggestions: The Impact of Conceptual Elaboration

    ERIC Educational Resources Information Center

    Zaragoza, Maria S.; Mitchell, Karen J.; Payment, Kristie; Drivdahl, Sarah

    2011-01-01

    Relatively little attention has been paid to the potential role that reflecting on the meaning and implications of suggested events (i.e., conceptual elaboration) might play in promoting the creation of false memories. Two experiments assessed whether encouraging repeated conceptual elaboration, would, like perceptual elaboration, increase false…

  2. PREFACE: Self-organized nanostructures

    NASA Astrophysics Data System (ADS)

    Rousset, Sylvie; Ortega, Enrique

    2006-04-01

    In order to fabricate ordered arrays of nanostructures, two different strategies might be considered. The `top-down' approach consists of pushing the limit of lithography techniques down to the nanometre scale. However, beyond 10 nm lithography techniques will inevitably face major intrinsic limitations. An alternative method for elaborating ultimate-size nanostructures is based on the reverse `bottom-up' approach, i.e. building up nanostructures (and eventually assemble them to form functional circuits) from individual atoms or molecules. Scanning probe microscopies, including scanning tunnelling microscopy (STM) invented in 1982, have made it possible to create (and visualize) individual structures atom by atom. However, such individual atomic manipulation is not suitable for industrial applications. Self-assembly or self-organization of nanostructures on solid surfaces is a bottom-up approach that allows one to fabricate and assemble nanostructure arrays in a one-step process. For applications, such as high density magnetic storage, self-assembly appears to be the simplest alternative to lithography for massive, parallel fabrication of nanostructure arrays with regular sizes and spacings. These are also necessary for investigating the physical properties of individual nanostructures by means of averaging techniques, i.e. all those using light or particle beams. The state-of-the-art and the current developments in the field of self-organization and physical properties of assembled nanostructures are reviewed in this issue of Journal of Physics: Condensed Matter. The papers have been selected from among the invited and oral presentations of the recent summer workshop held in Cargese (Corsica, France, 17-23 July 2005). All authors are world-renowned in the field. The workshop has been funded by the Marie Curie Actions: Marie Curie Conferences and Training Courses series named `NanosciencesTech' supported by the VI Framework Programme of the European Community, by

  3. Nanostructured photovoltaics

    NASA Astrophysics Data System (ADS)

    Fu, Lan; Tan, H. Hoe; Jagadish, Chennupati

    2013-01-01

    Energy and the environment are two of the most important global issues that we currently face. The development of clean and sustainable energy resources is essential to reduce greenhouse gas emission and meet our ever-increasing demand for energy. Over the last decade photovoltaics, as one of the leading technologies to meet these challenges, has seen a continuous increase in research, development and investment. Meanwhile, nanotechnology, which is considered to be the technology of the future, is gradually revolutionizing our everyday life through adaptation and incorporation into many traditional technologies, particularly energy-related technologies, such as photovoltaics. While the record for the highest efficiency is firmly held by multijunction III-V solar cells, there has never been a shortage of new research effort put into improving the efficiencies of all types of solar cells and making them more cost effective. In particular, there have been extensive and exciting developments in employing nanostructures; features with different low dimensionalities, such as quantum wells, nanowires, nanotubes, nanoparticles and quantum dots, have been incorporated into existing photovoltaic technologies to enhance their performance and/or reduce their cost. Investigations into light trapping using plasmonic nanostructures to effectively increase light absorption in various solar cells are also being rigorously pursued. In addition, nanotechnology provides researchers with great opportunities to explore the new ideas and physics offered by nanostructures to implement advanced solar cell concepts such as hot carrier, multi-exciton and intermediate band solar cells. This special issue of Journal of Physics D: Applied Physics contains selected papers on nanostructured photovoltaics written by researchers in their respective fields of expertise. These papers capture the current excitement, as well as addressing some open questions in the field, covering topics including the

  4. Genetics and the interpersonal elaboration of ethics.

    PubMed

    Parker, M

    2001-09-01

    Confidentiality in genetic testing poses important ethical challenges to the current primacy of respect for autonomy and patient choice in health care. It also presents a challenge to approaches to decision-making emphasising the ethical importance of the consequences of health care decisions. In this paper a case is described in which respect for confidentiality calls both for disclosure and non-disclosure, and in which respect for patient autonomy and the demand to avoid causing harm each appear to call both for testing without consent, and testing only with consent. This creates problems not only for clinicians, families and patients, but also for those who propose clinical bioethics as a tool for the resolution of such dilemmas. In this paper I propose some practical ways in which ethical issues in clinical genetics and elsewhere, might be addressed. In particular I call for a closer relationship between ethics and communication in health care decision-making and describe an approach to the ethics consultation that places particular emphasis on the value of interpersonal deliberation in the search for moral understanding. I reach these conclusions through an analysis of the concept of 'moral development' in which I argue that the achievement of moral understanding is a necessarily intersubjective project elaborated by moral persons. PMID:11808679

  5. Self-corrected elaboration and spacing effects in incidental memory.

    PubMed

    Toyota, Hiroshi

    2006-04-01

    The present study investigated the effect of self-corrected elaboration on incidental memory as a function of types of presentation (massed vs spaced) and sentence frames (image vs nonimage). The subjects were presented a target word and an incongruous sentence frame and asked to correct the target to make a common sentence in the self-corrected elaboration condition, whereas in the experimenter-corrected elaboration condition they were asked to rate the appropriateness of the congruous word presented, followed by free recall test. The superiority of the self-corrected elaboration to the experimenter-corrected elaboration was observed only in some situations of combinations by the types of presentation and sentence frames. These results were discussed in terms of the effectiveness of the self-corrected elaboration. PMID:16826672

  6. Elaborative Processing in the Korsakoff Syndrome: Context versus Habit

    ERIC Educational Resources Information Center

    Van Damme, Ilse; d'Ydewalle, Gery

    2008-01-01

    Using a procedure of Hay and Jacoby [Hay, J. F., & Jacoby, L. L. (1999). "Separating habit and recollection in young and older adults: Effects of elaborative processing and distinctiveness." "Psychology and Aging," 14, 122-134], Korsakoff patients' capacity to encode and retrieve elaborative, semantic information was investigated. Habits were…

  7. Elaborated Metaphors Support Viable Inferences about Difficult Science Concepts

    ERIC Educational Resources Information Center

    Diehl, Virginia; Reese, Debbie Denise

    2010-01-01

    Instructional metaphors scaffold learning better when accompanied by an elaboration. Applying structure mapping theory, we developed and used an elaborated instructional metaphor (text and illustrations) for introductory chemistry concepts. In two studies (N[subscript 1] = 44, N[subscript 2] = 57), college students with little chemistry background…

  8. Nanostructures from Synthetic Genetic Polymers.

    PubMed

    Taylor, Alexander I; Beuron, Fabienne; Peak-Chew, Sew-Yeu; Morris, Edward P; Herdewijn, Piet; Holliger, Philipp

    2016-06-16

    Nanoscale objects of increasing complexity can be constructed from DNA or RNA. However, the scope of potential applications could be enhanced by expanding beyond the moderate chemical diversity of natural nucleic acids. Here, we explore the construction of nano-objects made entirely from alternative building blocks: synthetic genetic polymers not found in nature, also called xeno nucleic acids (XNAs). Specifically, we describe assembly of 70 kDa tetrahedra elaborated in four different XNA chemistries (2'-fluro-2'-deoxy-ribofuranose nucleic acid (2'F-RNA), 2'-fluoroarabino nucleic acids (FANA), hexitol nucleic acids (HNA), and cyclohexene nucleic acids (CeNA)), as well as mixed designs, and a ∼600 kDa all-FANA octahedron, visualised by electron microscopy. Our results extend the chemical scope for programmable nanostructure assembly, with implications for the design of nano-objects and materials with an expanded range of structural and physicochemical properties, including enhanced biostability. PMID:26992063

  9. The elaboration likelihood model and communication about food risks.

    PubMed

    Frewer, L J; Howard, C; Hedderley, D; Shepherd, R

    1997-12-01

    Factors such as hazard type and source credibility have been identified as important in the establishment of effective strategies for risk communication. The elaboration likelihood model was adapted to investigate the potential impact of hazard type, information source, and persuasive content of information on individual engagement in elaborative, or thoughtful, cognitions about risk messages. One hundred sixty respondents were allocated to one of eight experimental groups, and the effects of source credibility, persuasive content of information and hazard type were systematically varied. The impact of the different factors on beliefs about the information and elaborative processing examined. Low credibility was particularly important in reducing risk perceptions, although persuasive content and hazard type were also influential in determining whether elaborative processing occurred. PMID:9463930

  10. Electrocatalytic (Bio)Nanostructures Based on Polymer-Grafted Platinum Nanoparticles for Analytical Purpose.

    PubMed

    Gal, François; Challier, Lylian; Cousin, Fabrice; Perez, Henri; Noel, Vincent; Carrot, Geraldine

    2016-06-15

    Functionalized platinum nanoparticles (PtNPs) possess electrocatalytic properties toward H2O2 oxidation, which are of great interest for the construction of electrochemical oxidoreductase-based sensors. In this context, we have shown that polymer-grafted PtNPs could efficiently be used as building bricks for electroactive structures. In the present work, we prepared different 2D-nanostructures based on these elementary bricks, followed by the subsequent grafting of enzymes. The aim was to provide well-defined architectures to establish a correlation between their electrocatalytic properties and the arrangement of building bricks. Two different nanostructures have been elaborated via the smart combination of surface initiated-atom transfer radical polymerization (SI-ATRP), functionalized PtNPs (Br-PtNPs) and Langmuir-Blodgett (LB) technique. The first nanostructure (A) has been elaborated from LB films of poly(methacrylic acid)-grafted PtNPs (PMAA-PtNPs). The second nanostructure (B) consisted in the elaboration of polymer brushes (PMAA brushes) from Br-PtNPs LB films. In both systems, grafting of the glucose oxidase (GOx) has been performed directly to nanostructures, via peptide bonding. Structural features of nanostructures have been carefully characterized (compression isotherms, neutron reflectivity, and profilometry) and correlated to their electrocatalytic properties toward H2O2 oxidation or glucose sensing. PMID:27192083

  11. Resist-free antireflective nanostructured film fabricated by thermal-NIL

    NASA Astrophysics Data System (ADS)

    Kang, Young Hun; Han, Jae Hyung; Cho, Song Yun; Choi, Choon-Gi

    2014-05-01

    Resist-free antireflective (AR) nanostructured films are directly fabricated on polycarbonate (PC) film using thermal-nanoimprint lithography (T-NIL) and the moth-eye shape of AR nanostructure is elaborately optimized with different oxygen reactive ion etching conditions. Anodic aluminum oxide (AAO) templates are directly used as master molds of T-NIL for preparation of AR nanostructures on PC film without an additional T-NIL resist. AR nanostructures are well arranged with a period of about 200 nm and diameter of about 150 nm, which corresponds to those of the AAO template mold. The moth-eye AR nanostructures exhibit the average reflectance of 2% in wavelength range from 400 to 800 nm. From the results, highly enhanced AR properties with simple direct imprinting on PC film demonstrate the potential for panel application in the field of flat display, touch screen, and solar cells.

  12. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  13. Formation of Partially and Fully Elaborated Generalized Equivalence Classes

    ERIC Educational Resources Information Center

    Fields, Lanny; Moss, Patricia

    2008-01-01

    Most complex categories observed in real-world settings consist of perceptually disparate stimuli, such as a picture of a person's face, the person's name as written, and the same name as heard, as well as dimensional variants of some or all of these stimuli. The stimuli function as members of a single partially or fully elaborated generalized…

  14. Learning about Posterior Probability: Do Diagrams and Elaborative Interrogation Help?

    ERIC Educational Resources Information Center

    Clinton, Virginia; Alibali, Martha W.; Nathan, Mitchell J.

    2016-01-01

    To learn from a text, students must make meaningful connections among related ideas in that text. This study examined the effectiveness of two methods of improving connections--elaborative interrogation and diagrams--in written lessons about posterior probability. Undergraduate students (N = 198) read a lesson in one of three questioning…

  15. Imagery and Semantic Elaboration in Hypermnesia for Words.

    ERIC Educational Resources Information Center

    Belmore, Susan M.

    1981-01-01

    Experiments were performed to determine the contribution of imagery and semantic factors to the hypermnesia effect (increases in retention over successive recall attempts). Results showed that hypermnesia accompanies meaningful processing regardless of whether verbal or imagery encoding is emphasized. Semantic elaboration increases reminiscence…

  16. Formative Research on Sequencing Instruction with the Elaboration Theory.

    ERIC Educational Resources Information Center

    English, Robert E.; Reigeluth, Charles M.

    The Elaboration Theory of Instruction offers guidelines for several patterns of simple-to-complex sequencing that were developed primarily from cognitive theory, especially schema theory, although there has been relatively little empirical research on the theory. This study helps fill this void by conducting "formative research" to identify…

  17. Simple versus Elaborate Feedback in a Nursing Science Course

    ERIC Educational Resources Information Center

    Elder, Betty L.; Brooks, David W.

    2008-01-01

    Feedback techniques, including computer-assisted feedback, have had mixed results in improving student learning outcomes. This project addresses the effect of type of feedback, simple or elaborate, for both short-term comprehension and long-term outcomes. A sample of 75 graduate nursing students was given a total of ten examinations. Four…

  18. Two Images of Schools as Organizations: A Refinement and Elaboration.

    ERIC Educational Resources Information Center

    Herriott, Robert E.; Firestone, William A.

    1984-01-01

    The finding reported previously in this journal (EJ 265 763), that elementary schools conform more to the image of the rational bureaucracy while secondary schools fit that of the anarchy or loosely coupled system, is reinforced and extended using a large sample, more reliable measures, and more elaborate techniques. (Author)

  19. Challenging Stereotypes about Academic Writing: Complexity, Elaboration, Explicitness

    ERIC Educational Resources Information Center

    Biber, Douglas; Gray, Bethany

    2010-01-01

    The stereotypical view of professional academic writing is that it is grammatically complex, with elaborated structures, and with meaning relations expressed explicitly. In contrast, spoken registers, especially conversation, are believed to have the opposite characteristics. Our goal in the present paper is to challenge these stereotypes, based…

  20. Elaborative and Integrative Thought Processes in Mathematics Learning.

    ERIC Educational Resources Information Center

    Swing, Susan; Peterson, Penelope

    1988-01-01

    The effects on mathematics achievement of having fifth graders engage in elaborative and integrative processing were studied using 121 students. Subjects were randomly assigned to cognitive-processing, fact-sheet, or control groups. Results show that cognitive processing is related to memory and understanding and is more effective for higher…

  1. The Impact of an Elaborated Assessee's Role in Peer Assessment

    ERIC Educational Resources Information Center

    Kim, Minjeong

    2009-01-01

    The purpose of this study was to investigate the effects of an elaborated assessee's role on metacognitive awareness, performance and attitude in peer assessment. Two intact groups (a total of 82 students) were randomly assigned to a treatment condition (having back-feedback activity) or a control condition (not having back-feedback activity). The…

  2. Counseling Pretreatment and the Elaboration Likelihood Model of Attitude Change.

    ERIC Educational Resources Information Center

    Heesacker, Martin

    The importance of high levels of involvement in counseling has been related to theories of interpersonal influence. To examine differing effects of counselor credibility as a function of how personally involved counselors are, the Elaboration Likelihood Model (ELM) of attitude change was applied to counseling pretreatment. Students (N=256) were…

  3. Counseling Pretreatment and the Elaboration Likelihood Model of Attitude Change.

    ERIC Educational Resources Information Center

    Heesacker, Martin

    1986-01-01

    Results of the application of the Elaboration Likelihood Model (ELM) to a counseling context revealed that more favorable attitudes toward counseling occurred as subjects' ego involvement increased and as intervention quality improved. Counselor credibility affected the degree to which subjects' attitudes reflected argument quality differences.…

  4. Dyad Composition Effects on Cognitive Elaboration and Student Achievement

    ERIC Educational Resources Information Center

    Denessen, Eddie; Veenman, Simon; Dobbelsteen, Janine; van Schilt, Josie

    2008-01-01

    The authors addressed the following research question: Does composition of dyads in terms of gender and ability affect student participation, the level of cognitive elaborations during a collaborative activity, and individual student achievement? The study involved 24 6th-grade dyads paired as follows: a low-ability student with a medium-ability…

  5. DNA nanostructures interacting with lipid bilayer membranes.

    PubMed

    Langecker, Martin; Arnaut, Vera; List, Jonathan; Simmel, Friedrich C

    2014-06-17

    CONSPECTUS: DNA has been previously shown to be useful as a material for the fabrication of static nanoscale objects, and also for the realization of dynamic molecular devices and machines. In many cases, nucleic acid assemblies directly mimic biological structures, for example, cytoskeletal filaments, enzyme scaffolds, or molecular motors, and many of the applications envisioned for such structures involve the study or imitation of biological processes, and even the interaction with living cells and organisms. An essential feature of biological systems is their elaborate structural organization and compartmentalization, and this most often involves membranous structures that are formed by dynamic assemblies of lipid molecules. Imitation of or interaction with biological systems using the tools of DNA nanotechnology thus ultimately and necessarily also involves interactions with lipid membrane structures, and thus the creation of DNA-lipid hybrid assemblies. Due to their differing chemical nature, however, highly charged nucleic acids and amphiphilic lipids do not seem the best match for the construction of such systems, and in fact they are rarely found in nature. In recent years, however, a large variety of lipid-interacting DNA conjugates were developed, which are now increasingly being applied also for the realization of DNA nanostructures interacting with lipid bilayer membranes. In this Account, we will present the current state of this emerging class of nanosystems. After a brief overview of the basic biophysical and biochemical properties of lipids and lipid bilayer membranes, we will discuss how DNA molecules can interact with lipid membranes through electrostatic interactions or via covalent modification with hydrophobic moieties. We will then show how such DNA-lipid interactions have been utilized for the realization of DNA nanostructures attached to or embedded within lipid bilayer membranes. Under certain conditions, DNA nanostructures remain mobile on

  6. Nanostructures from Synthetic Genetic Polymers

    PubMed Central

    Beuron, Fabienne; Peak‐Chew, Sew‐Yeu; Morris, Edward P.; Herdewijn, Piet

    2016-01-01

    Abstract Nanoscale objects of increasing complexity can be constructed from DNA or RNA. However, the scope of potential applications could be enhanced by expanding beyond the moderate chemical diversity of natural nucleic acids. Here, we explore the construction of nano‐objects made entirely from alternative building blocks: synthetic genetic polymers not found in nature, also called xeno nucleic acids (XNAs). Specifically, we describe assembly of 70 kDa tetrahedra elaborated in four different XNA chemistries (2′‐fluro‐2′‐deoxy‐ribofuranose nucleic acid (2′F‐RNA), 2′‐fluoroarabino nucleic acids (FANA), hexitol nucleic acids (HNA), and cyclohexene nucleic acids (CeNA)), as well as mixed designs, and a ∼600 kDa all‐FANA octahedron, visualised by electron microscopy. Our results extend the chemical scope for programmable nanostructure assembly, with implications for the design of nano‐objects and materials with an expanded range of structural and physicochemical properties, including enhanced biostability. PMID:26992063

  7. Microstructural and Optical Properties of Porous Alumina Elaborated on Glass Substrate

    NASA Astrophysics Data System (ADS)

    Zaghdoudi, W.; Gaidi, M.; Chtourou, R.

    2013-03-01

    A transparent porous anodized aluminum oxide (AAO) nanostructure was formed on a glass substrate using the anodization of a highly pure evaporated aluminum layer. A parametric study was carried out in order to achieve a fine control of the microstructural and optical properties of the elaborated films. The microstructural and surface morphologies of the porous alumina films were characterized by x-ray diffraction and atomic force microscopy. Pore diameter, inter-pore separation, and the porous structure as a function of anodization conditions were investigated. It was then found that the pores density decreases with increasing the anodization time. Regular cylindrical porous AAO films with a flat bottom structure were formed by chemical etching and anodization. A high transmittance in the 300-900 nm range is reported, indicating a fulfilled growth of the transparent sample (alumina) from the aluminum metal. The data showed typical interference oscillations as a result of the transparent characteristics of the film throughout the visible spectral range. The thickness and the optical constants ( n and k) of the porous anodic alumina films, as a function of anodizing time, were obtained using spectroscopic ellipsometry in the ultraviolet-visible-near infrared (UV-vis-NIR) regions.

  8. Further constraints on the Chauvet cave artwork elaboration.

    PubMed

    Sadier, Benjamin; Delannoy, Jean-Jacques; Benedetti, Lucilla; Bourlès, Didier L; Jaillet, Stéphane; Geneste, Jean-Michel; Lebatard, Anne-Elisabeth; Arnold, Maurice

    2012-05-22

    Since its discovery, the Chauvet cave elaborate artwork called into question our understanding of Palaeolithic art evolution and challenged traditional chronological benchmarks [Valladas H et al. (2001) Nature 413:419-479]. Chronological approaches revealing human presences in the cavity during the Aurignacian and the Gravettian are indeed still debated on the basis of stylistic criteria [Pettitt P (2008) J Hum Evol 55:908-917]. The presented (36)Cl Cosmic Ray Exposure ages demonstrate that the cliff overhanging the Chauvet cave has collapsed several times since 29 ka until the sealing of the cavity entrance prohibited access to the cave at least 21 ka ago. Remarkably agreeing with the radiocarbon dates of the human and animal occupancy, this study confirms that the Chauvet cave paintings are the oldest and the most elaborate ever discovered, challenging our current knowledge of human cognitive evolution. PMID:22566649

  9. [The six steps necessary in elaborating critically appraised topics].

    PubMed

    García Villar, C

    2014-01-01

    Different types of critically appraised topics (CATs) can be elaborated in diagnostic imaging: comparison of diagnostic tests, evaluation of techniques for early detection (screening), economical analyses, or therapeutic aspects, among others. Their design will vary in function of the question they aim to answer. For example, for treatment evaluation, clinical trials are the best, but if there are secondary studies (systematic reviews or meta-analyses) that synthesize information from several studies, the results will be more important and the scientific conclusions will be more relevant. Regardless of the study design used, the elaboration of a CAT will involve six steps: 1) question; 2) systematic and efficient bibliographic search; 3) levels of evidence (choosing the articles that have the best level); 4) critical reading of the articles chosen; 5) applying conclusions to the context, and 6) recommendations. In this article, we will describe these steps and the nuances for different types of studies in each step. PMID:25092391

  10. Further constraints on the Chauvet cave artwork elaboration

    PubMed Central

    Sadier, Benjamin; Delannoy, Jean-Jacques; Benedetti, Lucilla; Bourlès, Didier L.; Jaillet, Stéphane; Geneste, Jean-Michel; Lebatard, Anne-Elisabeth; Arnold, Maurice

    2012-01-01

    Since its discovery, the Chauvet cave elaborate artwork called into question our understanding of Palaeolithic art evolution and challenged traditional chronological benchmarks [Valladas H et al. (2001) Nature 413:419–479]. Chronological approaches revealing human presences in the cavity during the Aurignacian and the Gravettian are indeed still debated on the basis of stylistic criteria [Pettitt P (2008) J Hum Evol 55:908–917]. The presented 36Cl Cosmic Ray Exposure ages demonstrate that the cliff overhanging the Chauvet cave has collapsed several times since 29 ka until the sealing of the cavity entrance prohibited access to the cave at least 21 ka ago. Remarkably agreeing with the radiocarbon dates of the human and animal occupancy, this study confirms that the Chauvet cave paintings are the oldest and the most elaborate ever discovered, challenging our current knowledge of human cognitive evolution. PMID:22566649

  11. Elaboration of simplified vinca alkaloids and phomopsin hybrids.

    PubMed

    Ngo, Quoc Anh; Roussi, Fanny; Thoret, Sylviane; Guéritte, Françoise

    2010-03-01

    Nine simplified vinca alkaloids and phomospin A hybrids, in which vindoline moiety has been replaced by a simpler scaffold, have been elaborated to evaluate their activity on the inhibition of tubulin polymerization. This article deals with the synthesis of various simplified vinca alkaloids, using a stereoselective coupling of catharantine with reactive aromatic compounds and methanol as well as their subsequent condensation with a large peptide chain mimicking those of phomopsin A. Biological evaluation and molecular modeling studies are also reported. PMID:20659111

  12. 12. Examples of the elaborate and plain pressedsteel ceiling panels, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Examples of the elaborate and plain pressed-steel ceiling panels, here removed to the exterior of the building for photographing. A segment of the cornice has been placed above the larger panel. The panel on the left is comprised of four square components; the panel on the right is a single piece. Credit GADA/MRM. - Stroud Building, 31-33 North Central Avenue, Phoenix, Maricopa County, AZ

  13. Calibration and Data Elaboration Procedure for Sky Irradiance Measurements

    NASA Astrophysics Data System (ADS)

    Boi, Paolo; Tonna, Glauco; Dalu, Giuseppe; Nakajima, Teruyuki; Olivieri, Bruno; Pompei, Alberto; Campanelli, Monica; Rao, R.

    1999-02-01

    The problems encountered in the elaboration of measurements of direct and sky diffuse solar irradiance are the following: (1) to carry out the calibration for the direct irradiance, which consists in determining the direct irradiance at the upper limit of the atmosphere; (2) to carry out the calibration for the diffuse irradiance, which consists in determining the solid viewing angle of the sky radiometer; (3) to determine the input parameters, namely, ground albedo, real and imaginary parts of the aerosol refractive index, and aerosol radius range; and (4) to determine from the optical data the columnar aerosol optical depth and volume radius distribution. With experimental data and numerical simulations a procedure is shown that enables one to carry out the two calibrations needed for the sky radiometer, to determine a best estimate of the input parameters, and, finally, to obtain the average features of the atmospheric aerosols. An interesting finding is that inversion of only data of diffuse irradiance yields the same accuracy of result as data of both diffuse and direct irradiance; in this case, only calibration of the solid viewing angle of the sky radiometer is needed, thus shortening the elaboration procedure. Measurements were carried out in the Western Mediterranean Sea (Italy), in Tokyo (Japan), and in Ushuaia (Tierra del Fuego, Argentina); data were elaborated with a new software package, the Skyrad code, based on an efficient radiative transfer scheme.

  14. Calibration and data elaboration procedure for sky irradiance measurements.

    PubMed

    Boi, P; Tonna, G; Dalu, G; Nakajima, T; Olivieri, B; Pompei, A; Campanelli, M; Rao, R

    1999-02-20

    The problems encountered in the elaboration of measurements of direct and sky diffuse solar irradiance are the following: (1) to carry out the calibration for the direct irradiance, which consists in determining the direct irradiance at the upper limit of the atmosphere; (2) to carry out the calibration for the diffuse irradiance, which consists in determining the solid viewing angle of the sky radiometer; (3) to determine the input parameters, namely, ground albedo, real and imaginary parts of the aerosol refractive index, and aerosol radius range; and (4) to determine from the optical data the columnar aerosol optical depth and volume radius distribution. With experimental data and numerical simulations a procedure is shown that enables one to carry out the two calibrations needed for the sky radiometer, to determine a best estimate of the input parameters, and, finally, to obtain the average features of the atmospheric aerosols. An interesting finding is that inversion of only data of diffuse irradiance yields the same accuracy of result as data of both diffuse and direct irradiance; in this case, only calibration of the solid viewing angle of the sky radiometer is needed, thus shortening the elaboration procedure. Measurements were carried out in the Western Mediterranean Sea (Italy), in Tokyo (Japan), and in Ushuaia (Tierra del Fuego, Argentina); data were elaborated with a new software package, the Skyrad code, based on an efficient radiative transfer scheme. PMID:18305689

  15. Measuring Strong Nanostructures

    SciTech Connect

    Andy Minor

    2008-10-16

    Andy Minor of Berkeley Lab's National Center for Electron Microscopy explains measuring stress and strain on nanostructures with the In Situ Microscope. More information: http://newscenter.lbl.gov/press-relea...

  16. Bioinspired chemistry: Rewiring nanostructures

    NASA Astrophysics Data System (ADS)

    Ulijn, Rein V.; Caponi, Pier-Francesco

    2010-07-01

    The cell's dynamic skeleton, a tightly regulated network of protein fibres, continues to provide inspiration for the design of synthetic nanostructures. Genetic engineering has now been used to encode non-biological functionality within these structures.

  17. Measuring Strong Nanostructures

    ScienceCinema

    Andy Minor

    2010-01-08

    Andy Minor of Berkeley Lab's National Center for Electron Microscopy explains measuring stress and strain on nanostructures with the In Situ Microscope. More information: http://newscenter.lbl.gov/press-relea...

  18. Functionalized Metallated Cavitands via Imidation and Late-Stage Elaboration

    PubMed Central

    Zhao, Yanchuan

    2015-01-01

    Efficient methods for the preparation of functionalized metallated cavitands are described. Functional groups can be either introduced by an imidation of metal-oxo complexes or by a late-stage elaboration of the imido ligands. By using diversified iminophosphorane (PPh3=NR) reagents, π-conjugated pyrene, redox active ferrocene and polymerizable norbornene moieties were successfully introduced. Furthermore, the iodo and alkynyl groups on the imido ligands are capable of undergoing efficient Sonogashira cross-coupling and copper-catalyzed azide alkyne cycloaddition reactions, thereby providing facile access to complex architectures containing metallated cavitands. PMID:26962300

  19. New method of elaboration of the lidar signal

    NASA Astrophysics Data System (ADS)

    Stelmaszczyk, K.; Czyzewski, A.; Szymanski, A.; Pietruczuk, A.; Chudzynski, S.; Ernst, K.; Stacewicz, T.

    In lidar measurements noise and fluctuations strongly affect the results. The reason is a rapid decrease of the signal-to-noise ratio with an increase of distance. The differential absorption lidar (DIAL) is particularly sensitive to the signal instabilities. In this paper we present a method of the signal acquisition that is suitable for registration of both large light fluxes and single photons. We also present new method of solution of the DIAL equations. Compared to the traditional algorithm used for signal elaboration our procedures are much more stable and they are able to increase the effective range of lidar measurements.

  20. Architectures for Nanostructured Batteries

    NASA Astrophysics Data System (ADS)

    Rubloff, Gary

    2013-03-01

    Heterogeneous nanostructures offer profound opportunities for advancement in electrochemical energy storage, particularly with regard to power. However, their design and integration must balance ion transport, electron transport, and stability under charge/discharge cycling, involving fundamental physical, chemical and electrochemical mechanisms at nano length scales and across disparate time scales. In our group and in our DOE Energy Frontier Research Center (www.efrc.umd.edu) we have investigated single nanostructures and regular nanostructure arrays as batteries, electrochemical capacitors, and electrostatic capacitors to understand limiting mechanisms, using a variety of synthesis and characterization strategies. Primary lithiation pathways in heterogeneous nanostructures have been observed to include surface, interface, and both isotropic and anisotropic diffusion, depending on materials. Integrating current collection layers at the nano scale with active ion storage layers enhances power and can improve stability during cycling. For densely packed nanostructures as required for storage applications, we investigate both ``regular'' and ``random'' architectures consistent with transport requirements for spatial connectivity. Such configurations raise further important questions at the meso scale, such as dynamic ion and electron transport in narrow and tortuous channels, and the role of defect structures and their evolution during charge cycling. Supported as part of the Nanostructures for Electrical Energy Storage, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160

  1. Self-corrected elaboration effects on incidental memory.

    PubMed

    Toyota, Hiroshi

    2004-10-01

    Subjects performed an orienting task involving 3 conditions followed by an unexpected free recall test. The conditions were designed to force 3 types of corrected elaborations: Generated Correction, Chosen Correction, and No Correction. In the Generated Correction condition the subjects were presented with a target word (e.g., Baby) and a bizarre sentence frame (e.g., "____drinks beer.") and asked to correct the target to a congruous word (e.g., Uncle) to make a common sentence. In the Chosen Correction condition, the subjects were presented with a target and its bizarre sentence frame and asked to choose one of the alternative congruous words (e.g., Uncle, Aunt) to make a common sentence. In the No Correction condition, the subjects were presented with a target and its bizarre sentence frame and asked to rate the congruity of each target to its sentence frame. Generated Correction led to a better performance than Chosen Correction and No Correction, but a difference between the last two correction types was not found. These results were interpreted as showing that, by generating correct information, self-corrected elaboration led to facilitation of incidental memory. PMID:15560341

  2. Simple Versus Elaborate Feedback in a Nursing Science Course

    NASA Astrophysics Data System (ADS)

    Elder, Betty L.; Brooks, David W.

    2008-08-01

    Feedback techniques, including computer-assisted feedback, have had mixed results in improving student learning outcomes. This project addresses the effect of type of feedback, simple or elaborate, for both short-term comprehension and long-term outcomes. A sample of 75 graduate nursing students was given a total of ten examinations. Four examinations provided tutorials in which the students received one of two types of feedback, simple or elaborate. Five examinations provided tutorials with no feedback. A comprehensive final examination compared initial content and final scores. This study found no significant differences between the types of feedback the students received. The mean scores were significantly higher on the four examinations where the students received feedback than on the five examinations with no feedback on tutorials. The comparison between the individual examinations and the similar content portion of the final examination indicated a significant drop in each of the four examinations where feedback was given and a significant improvement in four of the five examinations where no feedback was given.

  3. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I.; Chen, Renkun; Delgado, Raul Diaz

    2015-12-22

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  4. Nanostructures having high performance thermoelectric properties

    DOEpatents

    Yang, Peidong; Majumdar, Arunava; Hochbaum, Allon I; Chen, Renkun; Delgado, Raul Diaz

    2014-05-20

    The invention provides for a nanostructure, or an array of such nanostructures, each comprising a rough surface, and a doped or undoped semiconductor. The nanostructure is an one-dimensional (1-D) nanostructure, such a nanowire, or a two-dimensional (2-D) nanostructure. The nanostructure can be placed between two electrodes and used for thermoelectric power generation or thermoelectric cooling.

  5. Say More and Be More Coherent: How Text Elaboration and Cohesion Can Increase Writing Quality

    ERIC Educational Resources Information Center

    Crossley, Scott A.; McNamara, Danielle S.

    2016-01-01

    This study examines links between essay quality and text elaboration and text cohesion. For this study, 35 students wrote two essays (on two different prompts) and for each, were given 15 minutes to elaborate on their original text. An expert in discourse comprehension then modified the original and elaborated essays to increase cohesion,…

  6. Deep-Elaborative Learning of Introductory Management Accounting for Business Students

    ERIC Educational Resources Information Center

    Choo, Freddie; Tan, Kim B.

    2005-01-01

    Research by Choo and Tan (1990; 1995) suggests that accounting students, who engage in deep-elaborative learning, have a better understanding of the course materials. The purposes of this paper are: (1) to describe a deep-elaborative instructional approach (hereafter DEIA) that promotes deep-elaborative learning of introductory management…

  7. Measuring Knowledge Elaboration Based on a Computer-Assisted Knowledge Map Analytical Approach to Collaborative Learning

    ERIC Educational Resources Information Center

    Zheng, Lanqin; Huang, Ronghuai; Hwang, Gwo-Jen; Yang, Kaicheng

    2015-01-01

    The purpose of this study is to quantitatively measure the level of knowledge elaboration and explore the relationships between prior knowledge of a group, group performance, and knowledge elaboration in collaborative learning. Two experiments were conducted to investigate the level of knowledge elaboration. The collaborative learning objective in…

  8. Elaboration over a Discourse Facilitates Retrieval in Sentence Processing.

    PubMed

    Troyer, Melissa; Hofmeister, Philip; Kutas, Marta

    2016-01-01

    Language comprehension requires access to stored knowledge and the ability to combine knowledge in new, meaningful ways. Previous work has shown that processing linguistically more complex expressions ('Texas cattle rancher' vs. 'rancher') leads to slow-downs in reading during initial processing, possibly reflecting effort in combining information. Conversely, when this information must subsequently be retrieved (as in filler-gap constructions), processing is facilitated for more complex expressions, possibly because more semantic cues are available during retrieval. To follow up on this hypothesis, we tested whether information distributed across a short discourse can similarly provide effective cues for retrieval. Participants read texts introducing two referents (e.g., two senators), one of whom was described in greater detail than the other (e.g., 'The Democrat had voted for one of the senators, and the Republican had voted for the other, a man from Ohio who was running for president'). The final sentence (e.g., 'The senator who the {Republican/Democrat}had voted for…') contained a relative clause picking out either the Many-Cue referent (with 'Republican') or the One-Cue referent (with 'Democrat'). We predicted facilitated retrieval (faster reading times) for the Many-Cue condition at the verb region ('had voted for'), where readers could understand that 'The senator' is the object of the verb. As predicted, this pattern was observed at the retrieval region and continued throughout the rest of the sentence. Participants also completed the Author/Magazine Recognition Tests (ART/MRT; Stanovich and West, 1989), providing a proxy for world knowledge. Since higher ART/MRT scores may index (a) greater experience accessing relevant knowledge and/or (b) richer/more highly structured representations in semantic memory, we predicted it would be positively associated with effects of elaboration on retrieval. We did not observe the predicted interaction between ART

  9. Elaboration over a Discourse Facilitates Retrieval in Sentence Processing

    PubMed Central

    Troyer, Melissa; Hofmeister, Philip; Kutas, Marta

    2016-01-01

    Language comprehension requires access to stored knowledge and the ability to combine knowledge in new, meaningful ways. Previous work has shown that processing linguistically more complex expressions (‘Texas cattle rancher’ vs. ‘rancher’) leads to slow-downs in reading during initial processing, possibly reflecting effort in combining information. Conversely, when this information must subsequently be retrieved (as in filler-gap constructions), processing is facilitated for more complex expressions, possibly because more semantic cues are available during retrieval. To follow up on this hypothesis, we tested whether information distributed across a short discourse can similarly provide effective cues for retrieval. Participants read texts introducing two referents (e.g., two senators), one of whom was described in greater detail than the other (e.g., ‘The Democrat had voted for one of the senators, and the Republican had voted for the other, a man from Ohio who was running for president’). The final sentence (e.g., ‘The senator who the {Republican/Democrat}had voted for…’) contained a relative clause picking out either the Many-Cue referent (with ‘Republican’) or the One-Cue referent (with ‘Democrat’). We predicted facilitated retrieval (faster reading times) for the Many-Cue condition at the verb region (‘had voted for’), where readers could understand that ‘The senator’ is the object of the verb. As predicted, this pattern was observed at the retrieval region and continued throughout the rest of the sentence. Participants also completed the Author/Magazine Recognition Tests (ART/MRT; Stanovich and West, 1989), providing a proxy for world knowledge. Since higher ART/MRT scores may index (a) greater experience accessing relevant knowledge and/or (b) richer/more highly structured representations in semantic memory, we predicted it would be positively associated with effects of elaboration on retrieval. We did not observe the

  10. Ultrafast Laser Synthesized Nanostructures for Controlling Cell Proliferation.

    PubMed

    Samarasekera, C; Tan, B; Venkatakrishnan, K

    2015-04-01

    The state-of-the-art in synthesis of nanostructured cell and contra-cell surfaces relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. Two type s of nanostructures, sodium oxide (Na2O) nanotips and silicon oxide (SiO2) nanofibers, have been fabricated on soda-lime glass using ultrafast laser ablation. Control over nanotip width was demonstrated via laser dwell time and a new tip formation mechanism is proposed. The nanofibers generated in this work display a level of nanomorphology unseen in other fiber fabrication methods. The resulting fibers show striking morphological similarity to proteins that comprise the natural extra cellular matrix. The interaction of both nanostructures with NIH 3T3 fibroblasts was explored by incubating nanostructured glass with fibroblasts over periods of 12 hours, 1 day, or 1 week. The Na2O nanotip surfaces dissolved within a day yet appeared to induce apoptosis in cells while the SiO2 nanofibers degraded over time but influenced cells to display unique, healthy characteristics such as preferential adhesion to nanofibers and increased microvilli generation. These growth-positive and growth-negative surfaces for cells could find use in novel biological testing equipment. PMID:26310069

  11. Nanostructures for enzyme stabilization

    SciTech Connect

    Kim, Jungbae; Grate, Jay W.; Wang, Ping

    2006-02-02

    The last decade has witnessed notable breakthroughs in nanotechnology with development of various nanostructured materials such as mesoporous materials and nanoparticles. These nanostructures have been used as a host for enzyme immobilization via various approaches, such as enzyme adsorption, covalent attachment, enzyme encapsulation, and sophisticated combinations of methods. This review discusses the stabilization mechanisms behind these diverse approaches; such as confinement, pore size and volume, charge interaction, hydrophobic interaction, and multipoint attachment. In addition, we will introduce recent rigorous approaches to improve the enzyme stability in these nanostructures or develop new nanostructures for the enzyme stabilization. Especially, we will introduce our recent invention of a nanostructure, called single enzyme nanoparticles (SENs). In the form of SENs, each enzyme molecule is surrounded with a nanometer scale network, resulting in stabilization of enzyme activity without any serious limitation for the substrate transfer from solution to the active site. SENs can be further immobilized into mesoporous silica with a large surface area, providing a hierarchical approach for stable, immobilized enzyme systems for various applications, such as bioconversion, bioremediation, and biosensors.

  12. Independent elaboration of steroid hormone signaling pathways in metazoans.

    PubMed

    Markov, Gabriel V; Tavares, Raquel; Dauphin-Villemant, Chantal; Demeneix, Barbara A; Baker, Michael E; Laudet, Vincent

    2009-07-21

    Steroid hormones regulate many physiological processes in vertebrates, nematodes, and arthropods through binding to nuclear receptors (NR), a metazoan-specific family of ligand-activated transcription factors. The main steps controlling the diversification of this family are now well-understood. In contrast, the origin and evolution of steroid ligands remain mysterious, although this is crucial for understanding the emergence of modern endocrine systems. Using a comparative genomic approach, we analyzed complete metazoan genomes to provide a comprehensive view of the evolution of major enzymatic players implicated in steroidogenesis at the whole metazoan scale. Our analysis reveals that steroidogenesis has been independently elaborated in the 3 main bilaterian lineages, and that steroidogenic cytochrome P450 enzymes descended from those that detoxify xenobiotics. PMID:19571007

  13. Nanostructured materials for hydrogen storage

    DOEpatents

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  14. Nanostructured Biomaterials for Regeneration**

    PubMed Central

    Wei, Guobao; Ma, Peter X.

    2009-01-01

    Biomaterials play a pivotal role in regenerative medicine, which aims to regenerate and replace lost/dysfunctional tissues or organs. Biomaterials (scaffolds) serve as temporary 3D substrates to guide neo tissue formation and organization. It is often beneficial for a scaffolding material to mimic the characteristics of extracellular matrix (ECM) at the nanometer scale and to induce certain natural developmental or/and wound healing processes for tissue regeneration applications. This article reviews the fabrication and modification technologies for nanofibrous, nanocomposite, and nanostructured drug-delivering scaffolds. ECM-mimicking nanostructured biomaterials have been shown to actively regulate cellular responses including attachment, proliferation, differentiation and matrix deposition. Nano-scaled drug delivery systems can be successfully incorporated into a porous 3D scaffold to enhance the tissue regeneration capacity. In conclusion, nano-structured biomateials are a very exciting and rapidly expanding research area, and are providing new enabling technologies for regenerative medicine. PMID:19946357

  15. Synthesis of porphyrin nanostructures

    DOEpatents

    Fan, Hongyou; Bai, Feng

    2014-10-28

    The present disclosure generally relates to self-assembly methods for generating porphyrin nanostructures. For example, in one embodiment a method is provided that includes preparing a porphyrin solution and a surfactant solution. The porphyrin solution is then mixed with the surfactant solution at a concentration sufficient for confinement of the porphyrin molecules by the surfactant molecules. In some embodiments, the concentration of the surfactant is at or above its critical micelle concentration (CMC), which allows the surfactant to template the growth of the nanostructure over time. The size and morphology of the nanostructures may be affected by the type of porphyrin molecules used, the type of surfactant used, the concentration of the porphyrin and surfactant the pH of the mixture of the solutions, and the order of adding the reagents to the mixture, to name a few variables.

  16. Plasmonic nanostructures: artificial molecules.

    PubMed

    Wang, Hui; Brandl, Daniel W; Nordlander, Peter; Halas, Naomi J

    2007-01-01

    This Account describes a new paradigm for the relationship between the geometry of metallic nanostructures and their optical properties. While the interaction of light with metallic nanoparticles is determined by their collective electronic or plasmon response, a compelling analogy exists between plasmon resonances of metallic nanoparticles and wave functions of simple atoms and molecules. Based on this insight, an entire family of plasmonic nanostructures, artificial molecules, has been developed whose optical properties can be understood within this picture: nanoparticles (nanoshells, nanoeggs, nanomatryushkas, nanorice), multi-nanoparticle assemblies (dimers, trimers, quadrumers), and a nanoparticle-over-metallic film, an electromagnetic analog of the spinless Anderson model. PMID:17226945

  17. Simulation of Semiconductor Nanostructures

    SciTech Connect

    Williamson, A J; Grossman, J C; Puzder, A; Benedict, L X; Galli, G

    2001-07-19

    The field of research into the optical properties of silicon nanostructures has seen enormous growth over the last decade. The discovery that silicon nanoparticles exhibit visible photoluminescence (PL) has led to new insights into the mechanisms responsible for such phenomena. The importance of understanding and controlling the PL properties of any silicon based material is of paramount interest to the optoelectronics industry where silicon nanoclusters could be embedded into existing silicon based circuitry. In this talk, we present a combination of quantum Monte Carlo and density functional approaches to the calculation of the electronic, structural, and optical properties of silicon nanostructures.

  18. Synthesis and performances of bio-sourced nanostructured carbon membranes elaborated by hydrothermal conversion of beer industry wastes

    PubMed Central

    2013-01-01

    Hydrothermal carbonization (HTC) process of beer wastes (Almaza Brewery) yields a biochar and homogeneous carbon-based nanoparticles (NPs). The NPs have been used to prepare carbon membrane on commercial alumina support. Water filtration experiments evidenced the quasi-dense behavior of the membrane with no measurable water flux below an applied nitrogen pressure of 6 bar. Gas permeation tests were conducted and gave remarkable results, namely (1) the existence of a limit temperature of utilization of the membrane, which was below 100°C in our experimental conditions, (2) an evolution of the microstructure of the carbon membrane with the operating temperature that yielded to improved performances in gas separation, (3) the temperature-dependent gas permeance should follow a Knudsen diffusion mechanism, and (4) He permeance was increasing with the applied pressure, whereas N2 and CO2 permeances remained stable in the same conditions. These results yielded an enhancement of both the He/N2 and He/CO2 permselectivities with the applied pressure. These promising results made biomass-sourced HTC-processed carbon membranes encouraging candidates as ultralow-cost and sustainable membranes for gas separation applications. PMID:23497215

  19. Synthesis and performances of bio-sourced nanostructured carbon membranes elaborated by hydrothermal conversion of beer industry wastes

    NASA Astrophysics Data System (ADS)

    El Korhani, Oula; Zaouk, Doumit; Cerneaux, Sophie; Khoury, Randa; Khoury, Antonio; Cornu, David

    2013-03-01

    Hydrothermal carbonization (HTC) process of beer wastes (Almaza Brewery) yields a biochar and homogeneous carbon-based nanoparticles (NPs). The NPs have been used to prepare carbon membrane on commercial alumina support. Water filtration experiments evidenced the quasi-dense behavior of the membrane with no measurable water flux below an applied nitrogen pressure of 6 bar. Gas permeation tests were conducted and gave remarkable results, namely (1) the existence of a limit temperature of utilization of the membrane, which was below 100°C in our experimental conditions, (2) an evolution of the microstructure of the carbon membrane with the operating temperature that yielded to improved performances in gas separation, (3) the temperature-dependent gas permeance should follow a Knudsen diffusion mechanism, and (4) He permeance was increasing with the applied pressure, whereas N2 and CO2 permeances remained stable in the same conditions. These results yielded an enhancement of both the He/N2 and He/CO2 permselectivities with the applied pressure. These promising results made biomass-sourced HTC-processed carbon membranes encouraging candidates as ultralow-cost and sustainable membranes for gas separation applications.

  20. Atomically Traceable Nanostructure Fabrication.

    PubMed

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-01-01

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure. PMID:26274555

  1. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2012-10-02

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  2. Nanostructured catalyst supports

    DOEpatents

    Zhu, Yimin; Goldman, Jay L.; Qian, Baixin; Stefan, Ionel C.

    2015-09-29

    The present invention relates to SiC nanostructures, including SiC nanopowder, SiC nanowires, and composites of SiC nanopowder and nanowires, which can be used as catalyst supports in membrane electrode assemblies and in fuel cells. The present invention also relates to composite catalyst supports comprising nanopowder and one or more inorganic nanowires for a membrane electrode assembly.

  3. Emerging double helical nanostructures

    NASA Astrophysics Data System (ADS)

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-07-01

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on `bottom-up' and `top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  4. Changes across age groups in self-choice elaboration and incidental memory.

    PubMed

    Toyota, Hiroshi; Tatsumi, Tomoko

    2003-04-01

    This study investigated differences in the self-choice elaboration and an experimenter-provided elaboration on incidental memory of 7- to 12-yr.-olds. In a self-choice elaboration condition 34 second and 25 sixth graders were asked to choose one of the two sentence frames into which each target could fit more congruously, whereas in an experimenter-provided elaboration they were asked to judge the congruity of each target to each frame. In free recall, sixth graders recalled targets in bizarre sentence frames better than second graders for self-choice elaboration condition. An age difference was not found for the experimenter-provided elaboration. In cued recall self-choice elaboration led to better performance of sixth graders for recalling targets than an experimenter-provided elaboration in both bizarre and common sentence frames. However, the different types of elaboration did not alter the recall of second graders. These results were interpreted as showing that the effectiveness of a self-choice elaboration depends on the subjects' age and the type of sentence. PMID:12776835

  5. Arbitrary integrated multimode interferometers for the elaboration of photonic qubits

    NASA Astrophysics Data System (ADS)

    Crespi, Andrea; Ramponi, Roberta; Brod, Daniel J.; Galvao, Ernesto F.; Spagnolo, Nicolò; Vitelli, Chiara; Sansoni, Linda; Sciarrino, Fabio; Mataloni, Paolo; Osellame, Roberto

    2014-03-01

    Integrated photonic circuits with many input and output modes are essential in applications ranging from conventional optical telecommunication networks, to the elaboration of photonic qubits in the integrated quantum information framework. In particular, the latter field has been object in the recent years of an increasing interest: the compactness and phase stability of integrated waveguide circuits are enabling experiments unconceivable with bulk-optics set-ups. Linear photonic devices for quantum information are based on quantum and classical interference effects: the desired circuit operation can be achieved only with tight fabrication control on both power repartition in splitting elements and phase retardance in the various paths. Here we report on a novel three-dimensional circuit architecture, made possible by the unique capabilities of femtosecond laser waveguide writing, which enables us to realize integrated multimode devices implementing arbitrary linear transformations. Networks of cascaded directional couplers can be built with independent control on the splitting ratios and the phase shifts in each branch. In detail, we show an arbitrarily designed 5×5 integrated interferometer: characterization with one- and two-photon experiments confirms the accuracy of our fabrication technique. We exploit the fabricated circuit to implement a small instance of the boson-sampling experiments with up to three photons, which is one of the most promising approaches to realize phenomena hard to simulate with classical computers. We will further show how, by studying classical and quantum interference in many random multimode circuits, we may gain deeper insight into the bosonic coalescence phenomenon.

  6. Elaboration, activity and stability of silica-based nitroaromatic sensors.

    PubMed

    Mercier, Dimitri; Pereira, Franck; Méthivier, Christophe; Montméat, Pierre; Hairault, Lionel; Pradier, Claire-Marie

    2013-08-21

    Functionalized silica-based thin films, modified with hydrophobic groups, were synthesized and used as sensors for nitroaromatic compound (NAC) specific detection. Their performance and behavior, in terms of stability, ageing and regeneration, have been fully characterized by combining chemical characterization techniques and electron microscopy. NAC was efficiently and specifically detected using these silica-based sensors, but showed a great degradation in the presence of humidity. Moreover, the sensor sensitivity seriously decreases with storage time. Methyl- and phenyl-functionalization helped to overcome this humidity sensitivity. Surface characterization enabled us to establish a direct correlation between the appearance, and increasing amount, of adsorbed carbonyl-containing species, and sensor efficiency. This contamination, appearing after only one month, was particularly important when sensors were stored in plastic containers. Rinsing with cyclohexane enables us to recover part of the sensor performance but does not yield a complete regeneration of the sensors. This work led us to the definition of optimized elaboration and storage conditions for nitroaromatic sensors. PMID:23812282

  7. Race of source effects in the elaboration likelihood model.

    PubMed

    White, P H; Harkins, S G

    1994-11-01

    In a series of experiments, we investigated the effect of race of source on persuasive communications in the Elaboration Likelihood Model (R.E. Petty & J.T. Cacioppo, 1981, 1986). In Experiment 1, we found no evidence that White participants responded to a Black source as a simple negative cue. Experiment 2 suggested the possibility that exposure to a Black source led to low-involvement message processing. In Experiments 3 and 4, a distraction paradigm was used to test this possibility, and it was found that participants under low involvement were highly motivated to process a message presented by a Black source. In Experiment 5, we found that attitudes toward the source's ethnic group, rather than violations of expectancies, accounted for this processing effect. Taken together, the results of these experiments are consistent with S.L. Gaertner and J.F. Dovidio's (1986) theory of aversive racism, which suggests that Whites, because of a combination of egalitarian values and underlying negative racial attitudes, are very concerned about not appearing unfavorable toward Blacks, leading them to be highly motivated to process messages presented by a source from this group. PMID:7983579

  8. The elaborate plumage in peacocks is not such a drag.

    PubMed

    Askew, Graham N

    2014-09-15

    One of the classic examples of an exaggerated sexually selected trait is the elaborate plumage that forms the train in male peafowl Pavo cristatus (peacock). Such ornaments are thought to reduce locomotor performance as a result of their weight and aerodynamic drag, but this cost is unknown. Here, the effect that the train has on take-off flight in peacocks was quantified as the sum of the rates of change of the potential and kinetic energies of the body (P(CoM)) in birds with trains and following the train's removal. There was no significant difference between P(CoM) in birds with and without a train. The train incurs drag during take-off; however, while this produces a twofold increase in parasite drag, parasite power only accounts for 0.1% of the total aerodynamic power. The train represented 6.9% of body weight and is expected to increase induced power. The absence of a detectable effect on take-off performance does not necessarily mean that there is no cost associated with possessing such ornate plumage; rather, it suggests that given the variation in take-off performance per se, the magnitude of any effect of the train has little meaningful functional relevance. PMID:25232196

  9. Elaborative Talk During and After an Event: Conversational Style Influences Children's Memory Reports.

    PubMed

    Hedrick, Amy M; Haden, Catherine A; Ornstein, Peter A

    2009-01-01

    An experimental design was utilized to examine the effects of elaborative talk during and/or after an event on children's event memory reports. Sixty preschoolers were assigned randomly to one of four conditions that varied according to a researcher's use of high or low elaborative during- and/or post-event talk about a camping event. In a memory conversation 1 day after the event, children who were engaged in high elaborative during-event talk and those whose memory conversation featured high elaborative post-event talk reported more information than children in low elaborative during- or post-event talk groups. Moreover, 3 weeks later, when a standard memory interview was conducted with all children, high elaborative during-event talk influenced the children's memory reports. PMID:25419186

  10. Problems in archaeomagnetic reference curves elaboration in the prehistoric past.

    NASA Astrophysics Data System (ADS)

    Avramova, M.; Kovacheva, M.; Boyadziev, Y.

    2012-04-01

    dated (perennial or annual) and cultural features. An example for such reference profile is the multilevel site Yunatzite from the Early Bronze Age. The comparison of archaeomagnetic profile Yunatzite with another archaeomagnetically studied Early Bronze Age multilevel site Djadovo shows very good agreement. Comparisons of other archaeomagnetic profiles available for Bulgaria related to the same epoch or sub-epoch will be presented. The expected correspondence can help the refinement of chronology of sites having only stratigraphic profiles. In our opinion the observed discrepancies between the local PSVCs for a given geographical region might be due mainly to the above described difficulties for elaboration of these curves in the prehistory. The further refinement and updating of existing archaeomagnetic databases will help considerably the elaboration of the newest geomagnetic field models. Acknowledgement: A partial financial support is from the Project "The archaeomagnetism - a key for solving fundamental problems in geophysics and archaeology", granted from the Bulgarian National Science Fund.

  11. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  12. Manganese Nanostructures and Magnetism

    NASA Astrophysics Data System (ADS)

    Simov, Kirie Rangelov

    The primary goal of this study is to incorporate adatoms with large magnetic moment, such as Mn, into two technologically significant group IV semiconductor (SC) matrices, e.g. Si and Ge. For the first time in the world, we experimentally demonstrate Mn doping by embedding nanostructured thin layers, i.e. delta-doping. The growth is observed by in-situ scanning tunneling microscopy (STM), which combines topographic and electronic information in a single image. We investigate the initial stages of Mn monolayer growth on a Si(100)(2x1) surface reconstruction, develop methods for classification of nanostructure types for a range of surface defect concentrations (1.0 to 18.2%), and subsequently encapsulate the thin Mn layer in a SC matrix. These experiments are instrumental in generating a surface processing diagram for self-assembly of monoatomic Mn-wires. The role of surface vacancies has also been studied by kinetic Monte Carlo modeling and the experimental observations are compared with the simulation results, leading to the conclusion that Si(100)(2x1) vacancies serve as nucleation centers in the Mn-Si system. Oxide formation, which happens readily in air, is detrimental to ferromagnetism and lessens the magnetic properties of the nanostructures. Therefore, the protective SC cap, composed of either Si or Ge, serves a dual purpose: it is both the embedding matrix for the Mn nanostructured thin film and a protective agent for oxidation. STM observations of partially deposited caps ensure that the nanostructures remain intact during growth. Lastly, the relationship between magnetism and nanostructure types is established by an in-depth study using x-ray magnetic circular dichroism (XMCD). This sensitive method detects signals even at coverages less than one atomic layer of Mn. XMCD is capable of discerning which chemical compounds contribute to the magnetic moment of the system, and provides a ratio between the orbital and spin contributions. Depending on the amount

  13. Thesis Abstract Fermented milk elaborated with Camellia sinensis.

    PubMed

    Ribeiro, O A S; Silva, M I A; Boari, C A

    2016-01-01

    This study aimed to develop and to characterize fermented dairy beverage formulated with Camellia sinensis. The infusion was elaborated with the addiction of dehydrated leaves of C. sinensis in whey (1g/100g) which added in sweetened milk (10% sucrose w/w) coagulated by Streptococcus salivarius subspecies thermophilus and Lactobacillus delbrueckii subspecies bulgaricus in proportions of 10, 20, 30 and 40% (v/w). The control treatment consisted of yogurt added with sucrose (10% w/w). Analysis were performed to quantify dry mass, moisture, ash, protein, fat, sodium, acidity, total quantification of lactic acid bacteria, total antioxidant activity and viscosity at the initial time of production and at 15 and 30 days of storage. Chromatographic determination of volatile compounds and sensory tests of acceptance and consumption intention were conducted at the initial time of production. Dry matter content, moisture, ash and total count of lactic acid bacteria from fermented milk drink formulations were not significantly affected by the amount of infusion of C. sinensis. However, the content of protein, fat and sodium were significantly lower with the increase of the proportion of infusion incorporated into the product. Significant reduction in apparent viscosity occurs with the increase in the amount of infusion added. The total antioxidant activity of the formulations was significantly higher as higher were the amount of added infusion. The addition of infusion contributed to the diversification of volatile aroma and taste makers in the product. The formulation of fermented dairy drink with addition of 30% infusion C. sinensis was better evaluated in sensory tests, with greater acceptance and greater consumer intent of consumption. PMID:27323046

  14. Nanostructured sulfur cathodes.

    PubMed

    Yang, Yuan; Zheng, Guangyuan; Cui, Yi

    2013-04-01

    Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes. PMID:23325336

  15. Planar plasmonic chiral nanostructures.

    PubMed

    Zu, Shuai; Bao, Yanjun; Fang, Zheyu

    2016-02-21

    A strong chiral optical response induced at a plasmonic Fano resonance in a planar Au heptamer nanostructure was experimentally and theoretically demonstrated. The scattering spectra show the characteristic narrow-band feature of Fano resonances for both left and right circular polarized lights, with a chiral response reaching 30% at the Fano resonance. Specifically, we systematically investigate the chiral response of planar heptamers with gradually changing the inter-particle rotation angles and separation distance. The chiral spectral characteristics clearly depend on the strength of Fano resonances and the associated near-field optical distributions. Finite element method simulations together with a multipole expansion method demonstrate that the enhanced chirality is caused by the excitation of magnetic quadrupolar and electric toroidal dipolar modes. Our work provides an effective method for the design of 2D nanostructures with a strong chiral response. PMID:26818746

  16. Nanostructured Superhydrophobic Coatings

    SciTech Connect

    2009-03-01

    This factsheet describes a research project that deals with the nanostructured superhydrophobic (SH) powders developed at ORNL. This project seeks to (1) improve powder quality; (2) identify binders for plastics, fiberglass, metal (steel being the first priority), wood, and other products such as rubber and shingles; (3) test the coated product for coating quality and durability under operating conditions; and (4) application testing and production of powders in quantity.

  17. Pickled luminescent silicon nanostructures

    NASA Astrophysics Data System (ADS)

    Boukherroub, R.; Morin, S.; Wayner, D. D. M.; Lockwood, D. J.

    2001-05-01

    In freshly prepared porous Si, the newly exposed silicon-nanostructure surface is protected with a monolayer of hydrogen, which is very reactive and oxidizes in air leading to a loss of luminescence intensity and a degradation of the electronic properties. We report a surface passivation approach based on organic modification that stabilizes the luminescence. This novel 'pickling' process not only augments the desired optoelectronic properties, but also is adaptable to further chemical modification for integration into chemical and biophysical sensors.

  18. Antibacterial Au nanostructured surfaces.

    PubMed

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies. PMID:26648134

  19. Coherent control near metallic nanostructures

    SciTech Connect

    Efimov, Ilya; Efimov, Anatoly

    2008-01-01

    We study coherent control in the vicinity of metallic nanostructures. Unlike in the case of control in gas or liquid phase, the collective response of electrons in a metallic nanostructure can significantly enhance different frequency components of the control field. This enhancement strongly depends on the geometry of the nanostructure and can substantially modify the temporal profile of the local control field. The changes in the amplitude and phase of the control field near the nanostructure are studied using linear response theory. The inverse problem of finding the external electromagnetic field to generate the desired local control field is considered and solved.

  20. Elaborative Talk during and after an Event: Conversational Style Influences Children's Memory Reports

    ERIC Educational Resources Information Center

    Hedrick, Amy M.; Haden, Catherine A.; Ornstein, Peter A.

    2009-01-01

    An experimental design was utilized to examine the effects of elaborative talk during and/or after an event on children's event memory reports. Sixty preschoolers were assigned randomly to one of four conditions that varied according to a researcher's use of high- or low- elaborative during- and/or post-event talk about a camping event. In a…

  1. Elaborations of Introductory Psychology Terms: Effects on Test Performance and Subjective Ratings

    ERIC Educational Resources Information Center

    Balch, William R.

    2005-01-01

    Undergraduate students participated in an experiment designed to evaluate different types of elaborations on definitions of 16 psychology terms. First, participants received booklets presenting the definition of each term, followed by 1 of several elaborations: an example, a mnemonic, a paraphrase, or a repeated definition (the nonelaborating…

  2. Learning from Science Text: Role of an Elaborate Analogy. Reading Research Report No. 71.

    ERIC Educational Resources Information Center

    Glynn, Shawn M.

    A study examined the role that an elaborate analogy can play when high school students learn a concept from a leading science textbook. The elaborate analogy had graphic and text components that integrated and mapped key features from the analogy (a factory) to the target concept (an animal cell). The target features were parts of the cell and, by…

  3. Cue Strength as a Moderator of the Testing Effect: The Benefits of Elaborative Retrieval

    ERIC Educational Resources Information Center

    Carpenter, Shana K.

    2009-01-01

    The current study explored the elaborative retrieval hypothesis as an explanation for the testing effect: the tendency for a memory test to enhance retention more than restudying. In particular, the retrieval process during testing may activate elaborative information related to the target response, thereby increasing the chances that activation…

  4. Effects of types of elaboration on children's memories of a story: interaction with academic performance.

    PubMed

    Toyota, Hiroshi

    2004-02-01

    Two experiments compared the effectiveness of three types of elaboration on incidental and intentional memory for a story: self-generated, self-choice, and experimenter-provided elaboration. In Exp. 1, using the incidental memory paradigm, second graders listened to a fantastic story and then, in the self-generated condition, answered a "why" question about a particular topic in the story. In the self-choice condition, they chose one of the alternative answers to the question and in the experimenter-provided condition, judged the appropriateness of each of two provided answers. This was followed by free-recall and cued-recall tests. Subjects were categorized into two groups, good and poor academic achievers in terms of academic scores in four subject matter areas. For good academic achievers, self-choice elaboration led to a better cued recall than the other two elaboration types. The cued-recall performance of poor achievers was not different with the three conditions. In Exp. 2, using the intentional memory paradigm, the subjects intended to learn a different story and then performed the same procedure as Exp. 1. For poor achievers, self-choice elaboration led to a worse free recall than the other elaboration types, but the free recall of good achievers was not significantly different for the three types of elaboration. The results were interpreted as showing that the effects of self-choice elaboration on incidental and intentional memory were correlated with subjects' academic performance. PMID:15077781

  5. The Expressive Elaboration of Imaginative Narratives by Children with Specific Language Impairment

    ERIC Educational Resources Information Center

    Ukrainetz, Teresa A.; Gillam, Ronald B.

    2009-01-01

    Purpose: This study investigated the expressive elaboration of narratives from children with specific language impairment (SLI). Method: Forty-eight 6- and 8-year-old children with SLI were compared with forty-eight 6- and 8-year-old typical language (TL) children. Two imaginative narratives were scored for 14 elements of expressive elaboration in…

  6. Use of Syntactic Elaboration Techniques to Enhance Comprehensibility of EST Texts

    ERIC Educational Resources Information Center

    Rahimi, Mohammad Ali; Rezaei, Amir

    2011-01-01

    The current study examined differential effects of two pre-modification types, syntactic elaboration and syntactic simplification (at the level of syntax and irrespective of problematic lexis), on EST students' reading comprehension. The purpose was to see whether a priori syntactic elaborative adjustment, given its advantages over simplification,…

  7. Socialization of Past Event Talk: Cultural Differences in Maternal Elaborative Reminiscing

    ERIC Educational Resources Information Center

    Tougu, Pirko; Tulviste, Tiia; Schroder, Lisa; Keller, Heidi; De Geer, Boel

    2011-01-01

    This study examines mother-child reminiscing conversations with respect to variation in use and function of mothers' elaborations, the nature of children's memory elaborations, and the connections between the two, in three Western middle-class cultures where autonomy is valued over relatedness. Mothers participated with their 4-year-old children…

  8. Using Elaborative Interrogation Enhanced Worked Examples to Improve Chemistry Problem Solving

    ERIC Educational Resources Information Center

    Pease, Rebecca Simpson

    2012-01-01

    Elaborative interrogation, which prompts students to answer why-questions placed strategically within informational text, has been shown to increase learning comprehension through reading. In this study, elaborative interrogation why-questions requested readers to explain why paraphrased statements taken from a reading were "true."…

  9. Maternal Elaborative Reminiscing Increases Low-Income Children's Narrative Skills Relative to Dialogic Reading

    ERIC Educational Resources Information Center

    Reese, Elaine; Leyva, Diana; Sparks, Alison; Grolnick, Wendy

    2010-01-01

    Research Findings: This study compared the unique effects of training low-income mothers in dialogic reading versus elaborative reminiscing on children's oral language and emergent literacy. Thirty-three low-income parents of 4-year-old children attending Head Start were randomly assigned to either dialogic reading, elaborative reminiscing, or a…

  10. Nanostructures for peroxidases.

    PubMed

    Carmona-Ribeiro, Ana M; Prieto, Tatiana; Nantes, Iseli L

    2015-01-01

    Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese, and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design, and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting, and reusability. PMID:26389124

  11. Nanoindentation of Carbon Nanostructures.

    PubMed

    Kumar, Dinesh; Singh, Karamjit; Verma, Veena; Bhatti, H S

    2016-06-01

    In the present research paper carbon nanostructures viz. single walled carbon nanotubes, multi-walled carbon nanotubes, single walled carbon nanohorns and graphene nanoplatelets have been synthesized by CVD technique, hydrothermal method, DC arc discharge method in liquid nitrogen and microwave technique respectively. After synthesis 5 mm thick pallets of given nanomaterial are prepared by making a paste in isopropyl alcohol and using polyvinylidene difluoride as a binder and then these pallets were used for nanoindentation measurements. Hardness, reduced modulus, stiffness, contact height and contact area have been measured using nanoindenter. PMID:27427726

  12. Biomimetics of photonic nanostructures

    NASA Astrophysics Data System (ADS)

    Parker, Andrew R.; Townley, Helen E.

    2007-06-01

    Biomimetics is the extraction of good design from nature. One approach to optical biomimetics focuses on the use of conventional engineering methods to make direct analogues of the reflectors and anti-reflectors found in nature. However, recent collaborations between biologists, physicists, engineers, chemists and materials scientists have ventured beyond experiments that merely mimic what happens in nature, leading to a thriving new area of research involving biomimetics through cell culture. In this new approach, the nanoengineering efficiency of living cells is harnessed and natural organisms such as diatoms and viruses are used to make nanostructures that could have commercial applications.

  13. Nanostructures for peroxidases

    PubMed Central

    Carmona-Ribeiro, Ana M.; Prieto, Tatiana; Nantes, Iseli L.

    2015-01-01

    Peroxidases are enzymes catalyzing redox reactions that cleave peroxides. Their active redox centers have heme, cysteine thiols, selenium, manganese, and other chemical moieties. Peroxidases and their mimetic systems have several technological and biomedical applications such as environment protection, energy production, bioremediation, sensors and immunoassays design, and drug delivery devices. The combination of peroxidases or systems with peroxidase-like activity with nanostructures such as nanoparticles, nanotubes, thin films, liposomes, micelles, nanoflowers, nanorods and others is often an efficient strategy to improve catalytic activity, targeting, and reusability. PMID:26389124

  14. Irradiation-Induced Nanostructures

    SciTech Connect

    Birtcher, R.C.; Ewing, R.C.; Matzke, Hj.; Meldrum, A.; Newcomer, P.P.; Wang, L.M.; Wang, S.X.; Weber, W.J.

    1999-08-09

    This paper summarizes the results of the studies of the irradiation-induced formation of nanostructures, where the injected interstitials from the source of irradiation are not major components of the nanophase. This phenomena has been observed by in situ transmission electron microscopy (TEM) in a number of intermetallic compounds and ceramics during high-energy electron or ion irradiations when the ions completely penetrate through the specimen. Beginning with single crystals, electron or ion irradiation in a certain temperature range may result in nanostructures composed of amorphous domains and nanocrystals with either the original composition and crystal structure or new nanophases formed by decomposition of the target material. The phenomenon has also been observed in natural materials which have suffered irradiation from the decay of constituent radioactive elements and in nuclear reactor fuels which have been irradiated by fission neutrons and other fission products. The mechanisms involved in the process of this nanophase formation are discussed in terms of the evolution of displacement cascades, radiation-induced defect accumulation, radiation-induced segregation and phase decomposition, as well as the competition between irradiation-induced amorphization and recrystallization.

  15. An elaboration of small opacity types (p, m, and n) in simple pneumoconiosis

    PubMed Central

    Lindars, D. C.

    1971-01-01

    Lindars, D. C. (1971).Brit. J. industr. Med.,28, 131-142. An elaboration of small opacity types (p, m, and n) in simple pneumoconiosis. According to the I.L.O. classification (International Labour Office, 1959), radiographs showing pneumoconiosis may be classified as p, m or n according to the greatest diameter of predominant (small) opacities. Recent work has revealed pathological and physiological differences associated with these appearances. In response to a request for some refinement of the classification for correlation with pathological data a `pmn elaboration' has been devised, analogous to the N.C.B. elaboration of the I.L.O. classification (Liddell and Lindars, 1969). It has the following form: o/-, o/o, o/p; p/o, p/p, p/m; m/p, m/m, m/n; n/m, n/n, n/A. Instructions to readers are similar to those for use with the N.C.B. elaboration. The significance of o/- and o/o is identical in the two elaborations; n/A indicates predominance of opacity size close to that of large opacities in the I.L.O. classification. Two hundred and forty-seven radiographs have been read, on two occasions by four film readers, using both elaborations. Analysis of the results showed that the readers had a slightly greater observer error, in terms of variance, when using the pmn elaboration than with the N.C.B. elaboration, but reading bias was less. Calculation of information transmitted showed a gain in information in the pmn elaboration over conventional p, m, n typing, comparable to the gain in information achieved by the N.C.B. elaboration. Marginal zones were not used as frequently as in the N.C.B. elaboration. The radiograph series contained too few normal or near-normal radiographs for the lower end of the scale to be adequately studied. Improved results can be expected with increased experience and more careful framing of reading instructions for prior briefing. It is recommended that the pmn elaboration should be used whenever typing is required for correlation between

  16. EDITORIAL: Nanostructured solar cells Nanostructured solar cells

    NASA Astrophysics Data System (ADS)

    Greenham, Neil C.; Grätzel, Michael

    2008-10-01

    Conversion into electrical power of even a small fraction of the solar radiation incident on the Earth's surface has the potential to satisfy the world's energy demands without generating CO2 emissions. Current photovoltaic technology is not yet fulfilling this promise, largely due to the high cost of the electricity produced. Although the challenges of storage and distribution should not be underestimated, a major bottleneck lies in the photovoltaic devices themselves. Improving efficiency is part of the solution, but diminishing returns in that area mean that reducing the manufacturing cost is absolutely vital, whilst still retaining good efficiencies and device lifetimes. Solution-processible materials, e.g. organic molecules, conjugated polymers and semiconductor nanoparticles, offer new routes to the low-cost production of solar cells. The challenge here is that absorbing light in an organic material produces a coulombically bound exciton that requires dissociation at a donor-acceptor heterojunction. A thickness of at least 100 nm is required to absorb the incident light, but excitons only diffuse a few nanometres before decaying. The problem is therefore intrinsically at the nano-scale: we need composite devices with a large area of internal donor-acceptor interface, but where each carrier has a pathway to the respective electrode. Dye-sensitized and bulk heterojunction cells have nanostructures which approach this challenge in different ways, and leading research in this area is described in many of the articles in this special issue. This issue is not restricted to organic or dye-sensitized photovoltaics, since nanotechnology can also play an important role in devices based on more conventional inorganic materials. In these materials, the electronic properties can be controlled, tuned and in some cases completely changed by nanoscale confinement. Also, the techniques of nanoscience are the natural ones for investigating the localized states, particularly at

  17. Picture Superiority in Free Recall: The Effects of Organization and Elaboration.

    ERIC Educational Resources Information Center

    Ritchey, Gary H.

    1980-01-01

    Tests the notion that activation in children's semantic memory might best be considered in terms of both between-item and within-item elaboration. Subjects were 192 second, fourth, and sixth graders. (MP)

  18. Mother-child reminiscing at risk: Maternal attachment, elaboration, and child autobiographical memory specificity.

    PubMed

    McDonnell, Christina G; Valentino, Kristin; Comas, Michelle; Nuttall, Amy K

    2016-03-01

    Mother-child reminiscing, the process by which mothers and their children discuss past events and emotional experiences, has been robustly linked with child outcomes, including autobiographical memory. To advance previous work linking elaborative maternal reminiscing with child autobiographical memory specificity, the ability to generate and retrieve specific memories from one's past, it is essential to make distinctions among aspects of elaboration and to consider how maternal risk factors may influence the reminiscing context. The current study evaluated (a) an interaction between emotional and structural elaboration predicting child autobiographical memory specificity and (b) the potential moderating role of maternal adult attachment. Participants consisted of 95 preschool-aged children and their mothers. The sample was predominantly low income and racially diverse. Dyads completed a reminiscing task that was coded for emotional and structural elaboration. Mothers completed the Experiences in Close Relationships questionnaire (ECR-R) to assess attachment-related avoidance and anxiety, and children completed the Autobiographical Memory Test-Preschool Version (AMT-PV) to assess memory specificity. Results indicated that the association between structural reminiscing and child memory specificity was moderated by emotional elements of reminiscing. At high levels of emotional elaboration, mothers with high levels of structural elaboration had children with more specific memory than mothers with low levels of structural elaboration. Moreover, emotional elaboration (a) predicted less specific child memory without high structural support and (b) negatively predicted child specificity at high levels of maternal attachment avoidance and anxiety, a profile associated with fearful avoidance. Future directions and implications are discussed. PMID:26630033

  19. The seahorse, the almond, and the night-mare: elaborative encoding during sleep-paralysis hallucinations?

    PubMed

    Girard, Todd A

    2013-12-01

    Llewellyn's proposal that rapid eye movement (REM) dreaming reflects elaborative encoding mediated by the hippocampus ("seahorse") offers an interesting perspective for understanding hallucinations accompanying sleep paralysis (SP; "night-mare"). SP arises from anomalous intrusion of REM processes into waking consciousness, including threat-detection systems mediated by the amygdala ("almond"). Unique aspects of SP hallucinations offer additional prospects for investigation of Llewellyn's theory of elaborative encoding. PMID:24304759

  20. Training Mothers in Elaborative Reminiscing Enhances Children's Autobiographical Memory and Narrative

    ERIC Educational Resources Information Center

    Reese, Elaine; Newcombe, Rhiannon

    2007-01-01

    This longitudinal intervention assessed children's memory at 2-1/2 years (short-term posttest; N = 115) and their memory and narrative at 3-1/2 years (long-term posttest; N = 100) as a function of maternal training in elaborative reminiscing when children were 1-1/2 to 2-1/2 years. At both posttests, trained mothers were more elaborative in their…

  1. Pheromone production, male abundance, body size, and the evolution of elaborate antennae in moths

    PubMed Central

    Symonds, Matthew RE; Johnson, Tamara L; Elgar, Mark A

    2012-01-01

    The males of some species of moths possess elaborate feathery antennae. It is widely assumed that these striking morphological features have evolved through selection for males with greater sensitivity to the female sex pheromone, which is typically released in minute quantities. Accordingly, females of species in which males have elaborate (i.e., pectinate, bipectinate, or quadripectinate) antennae should produce the smallest quantities of pheromone. Alternatively, antennal morphology may be associated with the chemical properties of the pheromone components, with elaborate antennae being associated with pheromones that diffuse more quickly (i.e., have lower molecular weights). Finally, antennal morphology may reflect population structure, with low population abundance selecting for higher sensitivity and hence more elaborate antennae. We conducted a phylogenetic comparative analysis to test these explanations using pheromone chemical data and trapping data for 152 moth species. Elaborate antennae are associated with larger body size (longer forewing length), which suggests a biological cost that smaller moth species cannot bear. Body size is also positively correlated with pheromone titre and negatively correlated with population abundance (estimated by male abundance). Removing the effects of body size revealed no association between the shape of antennae and either pheromone titre, male abundance, or mean molecular weight of the pheromone components. However, among species with elaborate antennae, longer antennae were typically associated with lower male abundances and pheromone compounds with lower molecular weight, suggesting that male distribution and a more rapidly diffusing female sex pheromone may influence the size but not the general shape of male antennae. PMID:22408739

  2. Elaborate visual and acoustic signals evolve independently in a large, phenotypically diverse radiation of songbirds

    PubMed Central

    Mason, Nicholas A.; Shultz, Allison J.; Burns, Kevin J.

    2014-01-01

    The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the ‘transfer hypothesis’ is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here, we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers. PMID:24943371

  3. Elaborate visual and acoustic signals evolve independently in a large, phenotypically diverse radiation of songbirds.

    PubMed

    Mason, Nicholas A; Shultz, Allison J; Burns, Kevin J

    2014-08-01

    The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the 'transfer hypothesis' is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here, we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers. PMID:24943371

  4. Repairable, nanostructured biomimetic hydrogels

    NASA Astrophysics Data System (ADS)

    Firestone, M.; Brombosz, S.; Grubjesic, S.

    2013-03-01

    Proteins facilitate many key cellular processes, including signal recognition and energy transduction. The ability to harness this evolutionarily-optimized functionality could lead to the development of protein-based systems useful for advancing alternative energy storage and conversion. The future of protein-based, however, requires the development of materials that will stabilize, order and control the activity of the proteins. Recently we have developed a synthetic approach for the preparation of a durable biomimetic chemical hydrogel that can be reversibly swollen in water. The matrix has proven ideal for the stable encapsulation of both water- and membrane-soluble proteins. The material is composed of an aqueous dispersion of a diacrylate end-derivatized PEO-PPO-PEO macromer, a saturated phospholipid and a zwitterionic co-surfactant that self-assembles into a nanostructured physical gel at room temperature as determined by X-ray scattering. The addition of a water soluble PEGDA co-monomer and photoinitator does not alter the self-assembled structure and UV irradiation serves to crosslink the acrylate end groups on the macromer with the PEGDA forming a network within the aqueous domains as determined by FT-IR. More recently we have begun to incorporate reversible crosslinks employing Diels-Alder chemistry, allowing for the extraction and replacement of inactive proteins. The ability to replenish the materials with active, non-denatured forms of protein is an important step in advancing these materials for use in nanostructured devices This work was supported by the Office of Basic Energy Sciences, Division of Materials Sciences, USDoE under Contract No. DE-AC02-06CH11357.

  5. TOPICAL REVIEW: Magnetic surface nanostructures

    NASA Astrophysics Data System (ADS)

    Enders, A.; Skomski, R.; Honolka, J.

    2010-11-01

    Recent trends in the emerging field of surface-supported magnetic nanostructures are reviewed. Current strategies for nanostructure synthesis are summarized, followed by a predominantly theoretical description of magnetic phenomena in surface magnetic structures and a review of experimental research in this field. Emphasis is on Fe- or Co-based nanostructures in various low-dimensional geometries, which are studied as model systems to explore the effects of dimensionality, atomic coordination, chemical bonds, alloying and, most importantly, interactions with the supporting substrate on the magnetism. This review also includes a discussion of closely related systems, such as 3d element impurities integrated into organic networks, surface-supported Fe-based molecular magnets, Kondo systems or 4d element nanostructures that exhibit emergent magnetism, thereby bridging the traditional areas of surface science, molecular physics and nanomagnetism.

  6. Nanostructured Materials for Renewable Energy

    SciTech Connect

    2009-11-01

    This factsheet describes a research project whose overall objective is to advance the fundamental understanding of novel photoelectronic organic device structures integrated with inorganic nanostructures, while also expanding the general field of nanomaterials for renewable energy devices and systems.

  7. Peptide nanostructures in biomedical technology.

    PubMed

    Feyzizarnagh, Hamid; Yoon, Do-Young; Goltz, Mark; Kim, Dong-Shik

    2016-09-01

    Nanostructures of peptides have been investigated for biomedical applications due to their unique mechanical and electrical properties in addition to their excellent biocompatibility. Peptides may form fibrils, spheres and tubes in nanoscale depending on the formation conditions. These peptide nanostructures can be used in electrical, medical, dental, and environmental applications. Applications of these nanostructures include, but are not limited to, electronic devices, biosensing, medical imaging and diagnosis, drug delivery, tissue engineering and stem cell research. This review offers a discussion of basic synthesis methods, properties and application of these nanomaterials. The review concludes with recommendations and future directions for peptide nanostructures. WIREs Nanomed Nanobiotechnol 2016, 8:730-743. doi: 10.1002/wnan.1393 For further resources related to this article, please visit the WIREs website. PMID:26846352

  8. Elaboration du Ge mesoporeux et etude de ses proprietes physico-chimiques en vue d'applications photovoltaiques

    NASA Astrophysics Data System (ADS)

    Tutashkonko, Sergii

    Le sujet de cette these porte sur l'elaboration du nouveau nanomateriau par la gravure electrochimique bipolaire (BEE) --- le Ge mesoporeux et sur l'analyse de ses proprietes physico-chimiques en vue de son utilisation dans des applications photovoltaiques. La formation du Ge mesoporeux par gravure electrochimique a ete precedemment rapportee dans la litterature. Cependant, le verrou technologique important des procedes de fabrication existants consistait a obtenir des couches epaisses (superieure a 500 nm) du Ge mesoporeux a la morphologie parfaitement controlee. En effet, la caracterisation physico-chimique des couches minces est beaucoup plus compliquee et le nombre de leurs applications possibles est fortement limite. Nous avons developpe un modele electrochimique qui decrit les mecanismes principaux de formation des pores ce qui nous a permis de realiser des structures epaisses du Ge mesoporeux (jusqu'au 10 mum) ayant la porosite ajustable dans une large gamme de 15% a 60%. En plus, la formation des nanostructures poreuses aux morphologies variables et bien controlees est desormais devenue possible. Enfin, la maitrise de tous ces parametres a ouvert la voie extremement prometteuse vers la realisation des structures poreuses a multi-couches a base de Ge pour des nombreuses applications innovantes et multidisciplinaires grace a la flexibilite technologique actuelle atteinte. En particulier, dans le cadre de cette these, les couches du Ge mesoporeux ont ete optimisees dans le but de realiser le procede de transfert de couches minces d'une cellule solaire a triple jonctions via une couche sacrificielle en Ge poreux. Mots-cles : Germanium meso-poreux, Gravure electrochimique bipolaire, Electrochimie des semi-conducteurs, Report des couches minces, Cellule photovoltaique

  9. Functionalized nanostructures for enhanced photocatalytic performance under solar light

    PubMed Central

    Liu, Maochang; Chen, Yubin; Shen, Shaohua; Shi, Jinwen; Zhang, Kai

    2014-01-01

    Summary Photocatalytic hydrogen production from water has been considered to be one of the most promising solar-to-hydrogen conversion technologies. In the last decade, various functionalized nanostructures were designed to address the primary requirements for an efficient photocatalytic generation of hydrogen by using solar energy: visible-light activity, chemical stability, appropriate band-edge characteristics, and potential for low-cost fabrication. Our aim is to present a short review of our recent attempts that center on the above requirements. We begin with a brief introduction of photocatalysts coupling two or more semiconductors, followed by a further discussion of the heterostructures with improved matching of both band structures and crystal lattices. We then elaborate on the heterostructure design of the targeted materials from macroscopic regulation of compositions and phases, to the more precise control at the nanoscale, i.e., materials with the same compositions but different phases with certain band alignment. We conclude this review with perspectives on nanostructure design that might direct future research of this technology. PMID:25161835

  10. Functionalized nanostructures for enhanced photocatalytic performance under solar light.

    PubMed

    Guo, Liejin; Jing, Dengwei; Liu, Maochang; Chen, Yubin; Shen, Shaohua; Shi, Jinwen; Zhang, Kai

    2014-01-01

    Photocatalytic hydrogen production from water has been considered to be one of the most promising solar-to-hydrogen conversion technologies. In the last decade, various functionalized nanostructures were designed to address the primary requirements for an efficient photocatalytic generation of hydrogen by using solar energy: visible-light activity, chemical stability, appropriate band-edge characteristics, and potential for low-cost fabrication. Our aim is to present a short review of our recent attempts that center on the above requirements. We begin with a brief introduction of photocatalysts coupling two or more semiconductors, followed by a further discussion of the heterostructures with improved matching of both band structures and crystal lattices. We then elaborate on the heterostructure design of the targeted materials from macroscopic regulation of compositions and phases, to the more precise control at the nanoscale, i.e., materials with the same compositions but different phases with certain band alignment. We conclude this review with perspectives on nanostructure design that might direct future research of this technology. PMID:25161835

  11. Chemically enabled nanostructure fabrication

    NASA Astrophysics Data System (ADS)

    Huo, Fengwei

    The first part of the dissertation explored ways of chemically synthesizing new nanoparticles and biologically guided assembly of nanoparticle building blocks. Chapter two focuses on synthesizing three-layer composite magnetic nanoparticles with a gold shell which can be easily functionalized with other biomolecules. The three-layer magnetic nanoparticles, when functionalized with oligonucleotides, exhibit the surface chemistry, optical properties, and cooperative DNA binding properties of gold nanoparticle probes, while maintaining the magnetic properties of the Fe3O4 inner shell. Chapter three describes a new method for synthesizing nanoparticles asymmetrically functionalized with oligonucleotides and the use of these novel building blocks to create satellite structures. This synthetic capability allows one to introduce valency into such structures and then use that valency to direct particle assembly events. The second part of the thesis explored approaches of nanostructure fabrication on substrates. Chapter four focuses on the development of a new scanning probe contact printing method, polymer pen lithography (PPL), which combines the advantages of muCp and DPN to achieve high-throughput, flexible molecular printing. PPL uses a soft elastomeric tip array, rather than tips mounted on individual cantilevers, to deliver inks to a surface in a "direct write" manner. Arrays with as many as ˜11 million pyramid-shaped pens can be brought into contact with substrates and readily leveled optically in order to insure uniform pattern development. Chapter five describes gel pen lithography, which uses a gel to fabricate pen array. Gel pen lithography is a low-cost, high-throughput nanolithography method especially useful for biomaterials patterning and aqueous solution patterning which makes it a supplement to DPN and PPL. Chapter 6 shows a novel form of optical nanolithography, Beam Pen Lithography (BPL), which uses an array of NSOM pens to do nanoscale optical

  12. Maternal elaborative reminiscing mediates the effect of child maltreatment on behavioral and physiological functioning.

    PubMed

    Valentino, Kristin; Hibel, Leah C; Cummings, E Mark; Nuttall, Amy K; Comas, Michelle; McDonnell, Christina G

    2015-11-01

    Theoretical and empirical evidence suggest that the way in which parents discuss everyday emotional experiences with their young children (i.e., elaborative reminiscing) has significant implications for child cognitive and socioemotional functioning, and that maltreating parents have a particularly difficult time in engaging in this type of dialogue. This dyadic interactional exchange, therefore, has the potential to be an important process variable linking child maltreatment to developmental outcomes at multiple levels of analysis. The current investigation evaluated the role of maternal elaborative reminiscing in associations between maltreatment and child cognitive, emotional, and physiological functioning. Participants included 43 maltreated and 49 nonmaltreated children (aged 3-6) and their mothers. Dyads participated in a joint reminiscing task about four past emotional events, and children participated in assessments of receptive language and emotion knowledge. Child salivary cortisol was also collected from children three times a day (waking, midday, and bedtime) on 2 consecutive days to assess daily levels and diurnal decline. Results indicated that maltreating mothers engaged in significantly less elaborative reminiscing than did nonmaltreating mothers. Maternal elaborative reminiscing mediated associations between child maltreatment and child receptive language and child emotion knowledge. In addition, there was support for an indirect pathway between child maltreatment and child cortisol diurnal decline through maternal elaborative reminiscing. Directions for future research are discussed, and potential clinical implications are addressed. PMID:26535941

  13. Maternal Elaborative Reminiscing Mediates the Effect of Child Maltreatment on Behavioral and Physiological Functioning

    PubMed Central

    Valentino, Kristin; Hibel, Leah C; Cummings, E. Mark; Nuttall, Amy K.; Comas, Michelle; McDonnell, Christina G.

    2016-01-01

    Theoretical and empirical evidence suggest that the way in which parents discuss everyday emotional experiences with their young children (i.e., elaborative reminiscing) has significant implications for child cognitive and socio-emotional functioning, and that maltreating parents have a particularly difficult time in engaging in this type of dialogue. This dyadic interactional exchange, therefore, has the potential to be an important process variable linking child maltreatment to developmental outcomes at multiple levels of analysis. The current investigation evaluated the role of maternal elaborative reminiscing in associations between maltreatment and child cognitive, emotional, and physiological functioning. Participants included 43 maltreated and 49 nonmaltreated children (aged 3–6) and their mothers. Dyads participated in a joint reminiscing task about four past emotional events, and children participated in assessments of receptive language and emotion knowledge. Child salivary cortisol was also collected from children three times a day (waking, midday, and bedtime) on two consecutive days to assess daily levels and diurnal decline. Results indicated that maltreating mothers engaged in significantly less elaborative reminiscing than nonmaltreating mothers. Maternal elaborative reminiscing mediated associations between child maltreatment and child receptive language and child emotion knowledge. Additionally, there was support for an indirect pathway between child maltreatment and child cortisol diurnal decline through maternal elaborative reminiscing. Directions for future research are discussed and potential clinical implications are addressed. PMID:26535941

  14. Wet-Chemically Synthesized Colloidal Semiconductor Nanostructures as Optical Gain Media.

    PubMed

    Ong, Xuanwei; Zhi, Min; Gupta, Shashank; Chan, Yinthai

    2016-03-01

    An overview on the development of wet-chemically synthesized semiconductor nanostructures as optical gain materials is presented in this Review, beginning with the first demonstration of amplified spontaneous emission in zero-dimensional quantum dots and evolving to more sophisticated heterostructures such as one-dimensional core-seeded nanorods, branched core-seeded tetrapods and two-dimensional nanoplatelets. The advantages and challenges of utilizing strongly quantum-confined colloidal semiconductor materials as gain media are discussed, and a concerted effort is made to elaborate on how the progression towards more structurally complex architectures has allowed for dramatic improvements in performance and stability over the archetypal quantum dot. PMID:26822201

  15. A nanostructured electrochromic supercapacitor.

    PubMed

    Wei, Di; Scherer, Maik R J; Bower, Chris; Andrew, Piers; Ryhänen, Tapani; Steiner, Ullrich

    2012-04-11

    We report the first successful application of an ordered bicontinuous double-gyroid vanadium pentoxide network in an electrochromic supercapacitor. The freestanding vanadia network was fabricated by electrodeposition into a voided block copolymer template that had self-assembled into the double-gyroid morphology. The highly ordered structure with 11.0 nm wide struts and a high specific surface to bulk volume ratio of 161.4 μm(-1) is ideal for fast and efficient lithium ion intercalation/extraction and faradaic surface reactions, which are essential for high energy and high power density electrochemical energy storage devices. Supercapacitors made from such gyroid-structured vanadia electrodes exhibit a high specific capacitance of 155 F g(-1) and show a strong electrochromic color change from green/gray to yellow, indicating the capacitor's charge condition. The nanostructuring approach and utilizing an electrode material that has intrinsic electrochemical color-change properties are concepts that can be readily extended to other electrochromic intercalation compounds. PMID:22390702

  16. Optics of anisotropic nanostructures

    NASA Astrophysics Data System (ADS)

    Rokushima, Katsu; Antoš, Roman; Mistrík, Jan; Višňovský, Štefan; Yamaguchi, Tomuo

    2006-07-01

    The analytical formalism of Rokushima and Yamakita [J. Opt. Soc. Am. 73, 901-908 (1983)] treating the Fraunhofer diffraction in planar multilayered anisotropic gratings proved to be a useful introduction to new fundamental and practical situations encountered in laterally structured periodic (both isotropic and anisotropic) multilayer media. These are employed in the spectroscopic ellipsometry for modeling surface roughness and in-depth profiles, as well as in the design of various frequency-selective elements including photonic crystals. The subject forms the basis for the solution of inverse problems in scatterometry of periodic nanostructures including magnetic and magneto-optic recording media. It has no principal limitations as for the frequencies and period to radiation wavelength ratios and may include matter wave diffraction. The aim of the paper is to make this formalism easily accessible to a broader community of students and non-specialists. Many aspects of traditional electromagnetic optics are covered as special cases from a modern and more general point of view, e.g., plane wave propagation in isotropic media, reflection and refraction at interfaces, Fabry-Perot resonator, optics of thin films and multilayers, slab dielectric waveguides, crystal optics, acousto-, electro-, and magneto-optics, diffraction gratings, etc. The formalism is illustrated on a model simulating the diffraction on a ferromagnetic wire grating.

  17. Ultrahard magnetic nanostructures

    SciTech Connect

    Sahota, PK; Liu, Y; Skomski, R; Manchanda, P; Zhang, R; Franchin, M; Fangohr, H; Hadjipanayis, GC; Kashyap, A; Sellmyer, DJ

    2012-04-01

    The performance of hard-magnetic nanostructures is investigated by analyzing the size and geometry dependence of thin-film hysteresis loops. Compared to bulk magnets, weight and volume are much less important, but we find that the energy product remains the main figure of merit down to very small features sizes. However, hysteresis loops are much easier to control on small length scales, as epitomized by Fe-Co-Pt thin films with magnetizations of up to 1.78 T and coercivities of up to 2.52 T. Our numerical and analytical calculations show that the feature size and geometry have a big effect on the hysteresis loop. Layered soft regions, especially if they have a free surface, are more harmful to coercivity and energy product than spherical inclusions. In hard-soft nanocomposites, an additional complication is provided by the physical properties of the hard phases. For a given soft phase, the performance of a hard-soft composite is determined by the parameter (M-s - M-h)/K-h. (C) 2012 American Institute of Physics. [doi:10.1063/1.3679453

  18. Ultrahard magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Sahota, P. K.; Liu, Y.; Skomski, R.; Manchanda, P.; Zhang, R.; Franchin, M.; Fangohr, H.; Hadjipanayis, G. C.; Kashyap, A.; Sellmyer, D. J.

    2012-04-01

    The performance of hard-magnetic nanostructures is investigated by analyzing the size and geometry dependence of thin-film hysteresis loops. Compared to bulk magnets, weight and volume are much less important, but we find that the energy product remains the main figure of merit down to very small features sizes. However, hysteresis loops are much easier to control on small length scales, as epitomized by Fe-Co-Pt thin films with magnetizations of up to 1.78 T and coercivities of up to 2.52 T. Our numerical and analytical calculations show that the feature size and geometry have a big effect on the hysteresis loop. Layered soft regions, especially if they have a free surface, are more harmful to coercivity and energy product than spherical inclusions. In hard-soft nanocomposites, an additional complication is provided by the physical properties of the hard phases. For a given soft phase, the performance of a hard-soft composite is determined by the parameter (Ms - Mh)/Kh.

  19. Phonon engineering for nanostructures.

    SciTech Connect

    Aubry, Sylvie; Friedmann, Thomas Aquinas; Sullivan, John Patrick; Peebles, Diane Elaine; Hurley, David H.; Shinde, Subhash L.; Piekos, Edward Stanley; Emerson, John Allen

    2010-01-01

    Understanding the physics of phonon transport at small length scales is increasingly important for basic research in nanoelectronics, optoelectronics, nanomechanics, and thermoelectrics. We conducted several studies to develop an understanding of phonon behavior in very small structures. This report describes the modeling, experimental, and fabrication activities used to explore phonon transport across and along material interfaces and through nanopatterned structures. Toward the understanding of phonon transport across interfaces, we computed the Kapitza conductance for {Sigma}29(001) and {Sigma}3(111) interfaces in silicon, fabricated the interfaces in single-crystal silicon substrates, and used picosecond laser pulses to image the thermal waves crossing the interfaces. Toward the understanding of phonon transport along interfaces, we designed and fabricated a unique differential test structure that can measure the proportion of specular to diffuse thermal phonon scattering from silicon surfaces. Phonon-scale simulation of the test ligaments, as well as continuum scale modeling of the complete experiment, confirmed its sensitivity to surface scattering. To further our understanding of phonon transport through nanostructures, we fabricated microscale-patterned structures in diamond thin films.

  20. The nanostructure problem

    SciTech Connect

    Billinge, S.

    2010-03-22

    Diffraction techniques are making progress in tackling the difficult problem of solving the structures of nanoparticles and nanoscale materials. The great gift of x-ray crystallography has made us almost complacent in our ability to locate the three-dimensional coordinates of atoms in a crystal with a precision of around 10{sup -4} nm. However, the powerful methods of crystallography break down for structures in which order only extends over a few nanometers. In fact, as we near the one hundred year mark since the birth of crystallography, we face a resilient frontier in condensed matter physics: our inability to routinely and robustly determine the structure of complex nanostructured and amorphous materials. Knowing the structure and arrangement of atoms in a solid is so fundamental to understanding its properties that the topic routinely occupies the early chapters of every solid-state physics textbook. Yet what has become clear with the emergence of nanotechnology is that diffraction data alone may not be enough to uniquely solve the structure of nanomaterials. As part of a growing effort to incorporate the results of other techniques to constrain x-ray refinements - a method called 'complex modeling' which is a simple but elegant approach for combining information from spectroscopy with diffraction data to solve the structure of several amorphous and nanostructured materials. Crystallography just works, so we rarely question how and why this is so, yet understanding the physics of diffraction can be very helpful as we consider the nanostructure problem. The relationship between the electron density distribution in three dimensions (i.e., the crystal structure) and an x-ray diffraction pattern is well established: the measured intensity distribution in reciprocal space is the square of the Fourier transform of the autocorrelation function <{rho}(r){rho}(r+r')> of the electron density distribution {rho}(r). The fact that we get the autocorrelation function

  1. Retrieval practice produces more learning than elaborative studying with concept mapping.

    PubMed

    Karpicke, Jeffrey D; Blunt, Janell R

    2011-02-11

    Educators rely heavily on learning activities that encourage elaborative studying, whereas activities that require students to practice retrieving and reconstructing knowledge are used less frequently. Here, we show that practicing retrieval produces greater gains in meaningful learning than elaborative studying with concept mapping. The advantage of retrieval practice generalized across texts identical to those commonly found in science education. The advantage of retrieval practice was observed with test questions that assessed comprehension and required students to make inferences. The advantage of retrieval practice occurred even when the criterial test involved creating concept maps. Our findings support the theory that retrieval practice enhances learning by retrieval-specific mechanisms rather than by elaborative study processes. Retrieval practice is an effective tool to promote conceptual learning about science. PMID:21252317

  2. Birdsong performance and the evolution of simple (rather than elaborate) sexual signals.

    PubMed

    Cardoso, Gonçalo C; Hu, Yang

    2011-11-01

    Sexual signals are often elaborate as a result of sexual selection for signals of individual quality. Contrary to expectation, however, the elaboration of signals such as birdsong is not related to the strength of sexual selection across species. With a comparative study across wood warblers (family Parulidae), we show a compromise between advertising the performance of trills (syllable repetitions) and song complexity, which can result in the evolution of simple, rather than elaborate, song. Species with higher trill performance evolved simple songs with more extensive trilled syntax. This advertises trill performance but reduces syllable diversity in songs. These two traits are commonly sexually selected in songbirds, but indexes of sexual selection were not related to either in wood warblers. This is consistent with sexual selection targeting different traits in different species, sometimes resulting in simple signals. We conclude that the evolution of sexual signals can be unpredictable when their physiology affords multiple or, as here, opposing ways of advertising individual quality. PMID:22030736

  3. Key Physical Mechanisms in Nanostructured Solar Cells

    SciTech Connect

    Dr Stephan Bremner

    2010-07-21

    The objective of the project was to study both theoretically and experimentally the excitation, recombination and transport properties required for nanostructured solar cells to deliver energy conversion efficiencies well in excess of conventional limits. These objectives were met by concentrating on three key areas, namely, investigation of physical mechanisms present in nanostructured solar cells, characterization of loss mechanisms in nanostructured solar cells and determining the properties required of nanostructured solar cells in order to achieve high efficiency and the design implications.

  4. Gallium nitride nanostructures: Synthesis, characterization and applications

    NASA Astrophysics Data System (ADS)

    Kente, Thobeka; Mhlanga, Sabelo Dalton

    2016-06-01

    GaN nanostructures have been extensively studied due to their important properties and applications in many fields. The recent synthesis and uses of these nanostructures have been reviewed. The different synthesis methods such as catalyst-assisted and catalyst-free methods to make GaN nanostructures and different reaction conditions have been also reviewed. This review covers the synthesis, growth mechanism, crystalline structure, properties, applications, structural and optical characterization of GaN nanostructures.

  5. Method of fabrication of anchored nanostructure materials

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  6. Nanostructures for protein drug delivery.

    PubMed

    Pachioni-Vasconcelos, Juliana de Almeida; Lopes, André Moreni; Apolinário, Alexsandra Conceição; Valenzuela-Oses, Johanna Karina; Costa, Juliana Souza Ribeiro; Nascimento, Laura de Oliveira; Pessoa, Adalberto; Barbosa, Leandro Ramos Souza; Rangel-Yagui, Carlota de Oliveira

    2016-02-01

    Use of nanoscale devices as carriers for drugs and imaging agents has been extensively investigated and successful examples can already be found in therapy. In parallel, recombinant DNA technology together with molecular biology has opened up numerous possibilities for the large-scale production of many proteins of pharmaceutical interest, reflecting in the exponentially growing number of drugs of biotechnological origin. When we consider protein drugs, however, there are specific criteria to take into account to select adequate nanostructured systems as drug carriers. In this review, we highlight the main features, advantages, drawbacks and recent developments of nanostructures for protein encapsulation, such as nanoemulsions, liposomes, polymersomes, single-protein nanocapsules and hydrogel nanoparticles. We also discuss the importance of nanoparticle stabilization, as well as future opportunities and challenges in nanostructures for protein drug delivery. PMID:26580477

  7. Interfacing nanostructures to biological cells

    DOEpatents

    Chen, Xing; Bertozzi, Carolyn R.; Zettl, Alexander K.

    2012-09-04

    Disclosed herein are methods and materials by which nanostructures such as carbon nanotubes, nanorods, etc. are bound to lectins and/or polysaccharides and prepared for administration to cells. Also disclosed are complexes comprising glycosylated nanostructures, which bind selectively to cells expressing glycosylated surface molecules recognized by the lectin. Exemplified is a complex comprising a carbon nanotube functionalized with a lipid-like alkane, linked to a polymer bearing repeated .alpha.-N-acetylgalactosamine sugar groups. This complex is shown to selectively adhere to the surface of living cells, without toxicity. In the exemplified embodiment, adherence is mediated by a multivalent lectin, which binds both to the cells and the .alpha.-N-acetylgalactosamine groups on the nanostructure.

  8. Nanostructured Substrates for Optical Sensing

    PubMed Central

    Kemling, Jonathan W.; Qavi, Abraham J.; Bailey, Ryan C.

    2011-01-01

    Sensors that change color have the advantages of versatility, ease of use, high sensitivity, and low cost. The recent development of optically based chemical sensing platforms has increasingly employed substrates manufactured with advanced processing or fabrication techniques to provide precise control over shape and morphology of the sensor micro- and nano-structure. New sensors have resulted with improved capabilities for a number of sensing applications, including the detection of biomolecules and environmental monitoring. This perspective focuses on recent optical sensor devices that utilize nanostructured substrates. PMID:22174955

  9. Vortex ice in nanostructured superconductors

    SciTech Connect

    Reichhardt, Charles; Reichhardt, Cynthia J; Libal, Andras J

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  10. Simulations with Elaborated Worked Example Modeling: Beneficial Effects on Schema Acquisition

    ERIC Educational Resources Information Center

    Meier, Debra K.; Reinhard, Karl J.; Carter, David O.; Brooks, David W.

    2008-01-01

    Worked examples have been effective in enhancing learning outcomes, especially with novice learners. Most of this research has been conducted in laboratory settings. This study examined the impact of embedding elaborated worked example modeling in a computer simulation practice activity on learning achievement among 39 undergraduate students…

  11. The Effect of Varied Elaboration Strategies in Facilitating Student Achievement of Different Educational Objectives.

    ERIC Educational Resources Information Center

    Jackson, Robert G.; Dwyer, Francis M.

    1995-01-01

    A study of 144 college students divided into high and low prior-knowledge groups and assigned to four treatment groups found (1) little interaction between prior knowledge of the human cardiovascular system and treatment and (2) significant effects on the drawing test. Terminology and elaboration tests revealed little effects among treatments.…

  12. Social justifications for moral emotions: when reasons for disgust are less elaborated than for anger.

    PubMed

    Russell, Pascale Sophie; Giner-Sorolla, Roger

    2011-06-01

    In the present research, we tested the unreasoning disgust hypothesis: moral disgust, in particular in response to a violation of a bodily norm, is less likely than moral anger to be justified with cognitively elaborated reasons. In Experiment 1, participants were asked to explain why they felt anger and disgust toward pedophiles. Participants were more likely to invoke elaborated reasons, versus merely evaluative responses, when explaining their anger, versus disgust. Experiment 2 used a between-participants design; participants explained why they felt either anger or disgust toward seven groups that either violated a sexual or nonsexual norm. Again, elaborated reasons were less prevalent when explaining their disgust versus anger and, in particular, when explaining disgust toward a group that violated a sexual norm. Experiment 3 further established that these findings are due to a lower accessibility of elaborated reasons for bodily disgust, rather than inhibition in using them when provided. From these findings, it can be concluded that communicating external reasons for moral disgust at bodily violations is made more difficult due to the unavailability of those reasons to people. PMID:21534665

  13. Evaluation of Smoking Prevention Television Messages Based on the Elaboration Likelihood Model

    ERIC Educational Resources Information Center

    Flynn, Brian S.; Worden, John K.; Bunn, Janice Yanushka; Connolly, Scott W.; Dorwaldt, Anne L.

    2011-01-01

    Progress in reducing youth smoking may depend on developing improved methods to communicate with higher risk youth. This study explored the potential of smoking prevention messages based on the Elaboration Likelihood Model (ELM) to address these needs. Structured evaluations of 12 smoking prevention messages based on three strategies derived from…

  14. Effects of Semantic Elaboration and Typicality on Picture Naming in Alzheimer Disease

    ERIC Educational Resources Information Center

    Morelli, Claudia A.; Altmann, Lori J. P.; Kendall, Diane; Fischler, Ira; Heilman, Kennneth M.

    2011-01-01

    Purpose: Individuals with probable Alzheimer disease (pAD) are frequently impaired at picture naming. This study examined whether a semantic elaboration task would facilitate naming in pAD, and whether training either semantically typical or atypical stimulus items facilitated generalized improvement in picture naming and category generation…

  15. Erotic Education: Elaborating a Feminist and Faith-Based Pedagogy for Experiential Learning in Religious Studies

    ERIC Educational Resources Information Center

    Carbine, Rosemary P.

    2010-01-01

    This essay explores intersections among Jesuit, Quaker, and feminist theologies and pedagogies of social justice education in order to propose and elaborate an innovative theoretical and theological framework for experiential learning in religious studies that prioritizes relationality, called erotic education. This essay then applies the…

  16. E(Lab)orating Performance: Transnationalism and Blended Learning in the Theatre Classroom

    ERIC Educational Resources Information Center

    Cloete, Nicola; Dinesh, Nandita; Hazou, Rand T.; Matchett, Sara

    2015-01-01

    "E(Lab)orating Performance" is a transnational collaborative teaching and learning project involving Massey University (New Zealand), University of Cape Town (South Africa), UWC Mahindra College (India), and University of the Witwatersrand (South Africa). The project was devised to facilitate creative engagements between students and…

  17. The Effects of Embedded and Elaborative Interrogation Questions on L2 Reading Comprehension

    ERIC Educational Resources Information Center

    Brantmeier, Cindy; Callender, Aimee; McDaniel, Mark

    2011-01-01

    With 97 advanced second language (L2) learners of Spanish, the present study utilized domain specific texts to examine the effects of embedded "what" questions and elaborative "why" questions on reading comprehension. Participants read two different vignettes, either with or without the adjuncts, from a social psychology textbook, and then…

  18. Relevant Prior Knowledge Moderates the Effect of Elaboration during Small Group Discussion on Academic Achievement

    ERIC Educational Resources Information Center

    Van Blankenstein, Floris M.; Dolmans, Diana H. J. M.; Van der Vleuten, Cees P. M.; Schmidt, Henk G.

    2013-01-01

    This study set out to test whether relevant prior knowledge would moderate a positive effect on academic achievement of elaboration during small-group discussion. In a 2 × 2 experimental design, 66 undergraduate students observed a video showing a small-group problem-based discussion about thunder and lightning. In the video, a teacher asked…

  19. Stratification, Elaboration and Formalisation of Design Documents: Effects on the Production of Instructional Materials

    ERIC Educational Resources Information Center

    Boot, Eddy W.; Nelson, Jon; van Merrienboer, Jeroen J. G.; Gibbons, Andrew S.

    2007-01-01

    Designers and producers of instructional materials lack a common design language. As a result, producers have difficulties translating design documents into technical specifications. The 3D-model is introduced to improve the stratification, elaboration and formalisation of design documents. It is hypothesised that producers working with improved…

  20. Physiological control of elaborate male courtship: Female choice for neuromuscular systems

    PubMed Central

    Fusani, Leonida; Barske, Julia; Day, Lainy D.; Fuxjager, Matthew J.; Schlinger, Barney A.

    2015-01-01

    Males of many animal species perform specialized courtship behaviours to gain copulations with females. Identifying physiological and anatomical specializations underlying performance of these behaviours helps clarify mechanisms through which sexual selection promotes the evolution of elaborate courtship. Our knowledge about neuromuscular specializations that support elaborate displays is limited to a few model species. In this review, we focus on the physiological control of the courtship of a tropical bird, the golden-collared manakin, which has been the focus of our research for nearly 20 years. Male manakins perform physically elaborate courtship displays that are quick, accurate and powerful. Females seem to choose males based on their motor skills suggesting that neuromuscular specializations possessed by these males are driven by female choice. Male courtship is activated by androgens and androgen receptors are expressed in qualitatively and quantitatively unconventional ways in manakin brain, spinal cord and skeletal muscles. We propose that in some species, females select males based on their neuromuscular capabilities and acquired skills and that elaborate steroid-dependent courtship displays evolve to signal these traits. PMID:25086380

  1. Enhancing Learning Outcomes in Computer-Based Training via Self-Generated Elaboration

    ERIC Educational Resources Information Center

    Cuevas, Haydee M.; Fiore, Stephen M.

    2014-01-01

    The present study investigated the utility of an instructional strategy known as the "query method" for enhancing learning outcomes in computer-based training. The query method involves an embedded guided, sentence generation task requiring elaboration of key concepts in the training material that encourages learners to "stop and…

  2. Modified Response Elaboration Training: Application to Procedural Discourse and Personal Recounts

    ERIC Educational Resources Information Center

    Wambaugh, Julie L.; Nessler, Christina; Wright, Sandra

    2013-01-01

    Purpose: This investigation was designed to examine the effects of a modification of response elaboration training (RET; Kearns, 1985) with speakers with mild to mild-moderate aphasia. The modification entailed application of RET to procedural discourse and personal recounts rather than to narrative discourse. Method: Three participants with…

  3. Reason, Intuition, and Social Justice: Elaborating on Parson's Career Decision-Making Model.

    ERIC Educational Resources Information Center

    Hartung, Paul J.; Blustein, David L.

    2002-01-01

    Nearly a century ago, Frank Parsons established the Vocation Bureau in Boston and spawned the development of the counseling profession. Elaborating on Parsons's socially responsible vision for counseling, the authors examine contemporary perspectives on career decision making that include both rational and alternative models and propose that these…

  4. Functional and effective hippocampal-neocortical connectivity during construction and elaboration of autobiographical memory retrieval.

    PubMed

    McCormick, Cornelia; St-Laurent, Marie; Ty, Ambrose; Valiante, Taufik A; McAndrews, Mary Pat

    2015-05-01

    Autobiographical memory (AM) provides the opportunity to study interactions among brain areas that support the search for a specific episodic memory (construction), and the later experience of mentally reliving it (elaboration). While the hippocampus supports both construction and elaboration, it is unclear how hippocampal-neocortical connectivity differs between these stages, and how this connectivity involves the anterior and posterior segments of the hippocampus, as these have been considered to support the retrieval of general concepts and recollection processes, respectively. We acquired fMRI data in 18 healthy participants during an AM retrieval task in which participants were asked to access a specific AM (construction) and then to recollect it by recovering as many episodic details as possible (elaboration). Using multivariate analytic techniques, we examined changes in functional and effective connectivity of hippocampal-neocortical interactions during these phases of AM retrieval. We found that the left anterior hippocampus interacted with frontal areas during construction and bilateral posterior hippocampi with visual perceptual areas during elaboration, indicating key roles for both hippocampi in coordinating transient neocortical networks at both AM stages. Our findings demonstrate the importance of direct interrogation of hippocampal-neocortical interactions to better illuminate the neural dynamics underlying complex cognitive tasks such as AM retrieval. PMID:24275829

  5. An Elaboration on the Effect of Reading Anxiety on Reading Achievement

    ERIC Educational Resources Information Center

    Mohammadpur, Bijan; Ghafournia, Narjes

    2015-01-01

    The present study was an elaboration on the effect of foreign language anxiety on reading comprehension achievement of Iranian EFL learners. The participants comprised 100 BA students, doing General English Course in different academic fields at Islamic University of Neyshabur. The participants took a reading proficiency test of TOEFL and answered…

  6. Intentionality as Measured in the Persistence and Elaboration of Communication by Chimpanzees (Pan troglodytes)

    ERIC Educational Resources Information Center

    Leavens, David A.; Russell, Jamie L.; Hopkins, William D.

    2005-01-01

    In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana…

  7. Collaborative Argumentation and Cognitive Elaboration in a Computer-Supported Collaborative Learning Environment

    ERIC Educational Resources Information Center

    Stegmann, Karsten; Wecker, Christof; Weinberger, Armin; Fischer, Frank

    2012-01-01

    This study explores the relation between argumentation in online discussions, cognitive elaboration, and individual knowledge acquisition. In a one-factorial experimental design with 48 participants we investigated the effect of an argumentative computer-supported collaboration script (with vs. without) on the formal quality of argumentation,…

  8. Training maltreating parents in elaborative and emotion-rich reminiscing with their preschool-aged children

    PubMed Central

    Valentino, Kristin; Comas, Michelle; Nuttall, Amy K.; Thomas, Taylor

    2013-01-01

    Objective In the current study, the effects of training maltreating parents and their preschool-aged children in elaborative and emotion-rich reminiscing were examined. Method 44 parent-child dyads were randomly assigned to a training (reminiscing) or wait-list (control) condition. All participating parents had substantiated maltreatment and were involved with the Department of Child Services at the time of enrollment. Children were 3–6 years old (M = 4.88, SD = .99) and living in the custody of the participating parent. Dyads in the reminiscing condition received four, weekly, in-home sessions in elaborative and emotion rich reminiscing. Results At a follow-up assessment, maltreating parents in the reminiscing condition provided more high-elaborative utterances, references to children’s negative emotions, and explanations of children’s emotion during reminiscing than did parents in the control condition. Children in the reminiscing condition had richer memory recall and made more emotion references than did children in the control condition during reminiscing with their mothers, but not with an experimenter. Conclusion The findings suggest that maltreating parents can be taught elaborative and emotion-rich reminiscing skills, with benefits for child cognitive and emotional development. The potential clinical utility of a reminiscing-based training for maltreating families with young children is discussed. PMID:23548682

  9. The Elaboration Likelihood Model and Proxemic Violations as Peripheral Cues to Information Processing.

    ERIC Educational Resources Information Center

    Eaves, Michael

    This paper provides a literature review of the elaboration likelihood model (ELM) as applied in persuasion. Specifically, the paper addresses distraction with regard to effects on persuasion. In addition, the application of proxemic violations as peripheral cues in message processing is discussed. Finally, the paper proposes to shed new light on…

  10. Illustrating Story Plans: Does a Mnemonic Strategy Including Art Media Render More Elaborate Text?

    ERIC Educational Resources Information Center

    Dunn, Michael W.

    2012-01-01

    Students who have difficulty with academics often benefit from learning mnemonic strategies which provide a step-by-step process to accomplish a task. Three fourth-grade students who struggled with writing learned the Ask, Reflect, Text (ART) strategy to help them produce more elaborate narrative story text. After initially asking the questions…

  11. Toward an Episodic Context Account of Retrieval-Based Learning: Dissociating Retrieval Practice and Elaboration

    ERIC Educational Resources Information Center

    Lehman, Melissa; Smith, Megan A.; Karpicke, Jeffrey D.

    2014-01-01

    We tested the predictions of 2 explanations for retrieval-based learning; while the elaborative retrieval hypothesis assumes that the retrieval of studied information promotes the generation of semantically related information, which aids in later retrieval (Carpenter, 2009), the episodic context account proposed by Karpicke, Lehman, and Aue (in…

  12. Predicting Elements of Early Maternal Elaborative Discourse from 12 to 18 Months of Age

    ERIC Educational Resources Information Center

    Ontai, Lenna L.; Virmani, Elita Amini

    2010-01-01

    To date, much of the research investigating maternal-child discourse has focused on the preschool period of children's development, with little attention paid to how these styles develop. The current study aimed to assess whether maternal elaborative discourse elements seen in preschool are also evident during the toddler years, and whether the…

  13. Other People's Students Elaborated Codes and Dialect in Basic Writing

    ERIC Educational Resources Information Center

    Evans, Jason Cory

    2012-01-01

    English teachers, especially those in the field of basic writing, have long debated how to teach writing to students whose home language differs from the perceived norm. This thesis intervenes in that stalemated debate by re-examining "elaborated codes" and by arguing for a type of correctness in writing that includes being correct…

  14. Autobiographical Elaboration Reduces Memory Distortion: Cognitive Operations and the Distinctiveness Heuristic

    ERIC Educational Resources Information Center

    McDonough, Ian M.; Gallo, David A.

    2008-01-01

    Retrieval monitoring enhances episodic memory accuracy. For instance, false recognition is reduced when participants base their decisions on more distinctive recollections, a retrieval monitoring process called the distinctiveness heuristic. The experiments reported here tested the hypothesis that autobiographical elaboration during study (i.e.,…

  15. Conductance fluctuations in nanostructures

    NASA Astrophysics Data System (ADS)

    Zhu, Ningjia

    1997-12-01

    In this Ph.D thesis the conductance fluctuations of different physical origins in semi-conductor nanostructures were studied using both diagrammatic analytical methods and large scale numerical techniques. In the "mixed" transport regime where both mesoscopic and ballistic features play a role, for the first time I have analytically calculated the non-universal conductance fluctuations. This mixed regime is reached when impurities are distributed near the walls of a quantum wire, leaving the center region ballistic. I have discovered that the existence of a ballistic region destroys the universal conductance fluctuations. The crossover behavior of the fluctuation amplitude from the usual quasi-1D situation to that of the mixed regime is clearly revealed, and the role of various length scales are identified. My analytical predictions were confirmed by a direct numerical simulation by evaluating the Landauer formula. In another direction, I have made several studies of conductance or resistance oscillations and fluctuations in systems with artificial impurities in the ballistic regime. My calculation gave explanations of all the experimental results concerning the classical focusing peaks of the resistance versus magnetic field, the weak localization peak in a Sinai billiard system, the formation of a chaotic billiard, and predicted certain transport features which were indeed found experimentally. I have further extended the calculation to study the Hall resistance in a four-terminal quantum dot in which there is an antidot array. From my numerical data I analyzed the classical paths of electron motion and its quantum oscillations. The results compare well with recent experimental studies on similar systems. Since these billiard systems could provide quantum chaotic dynamics, I have made a detailed study of the consequence of such dynamics. In particular I have investigated the resonant transmission of electrons in these chaotic systems, and found that the level

  16. Controlled placement and orientation of nanostructures

    DOEpatents

    Zettl, Alex K; Yuzvinsky, Thomas D; Fennimore, Adam M

    2014-04-08

    A method for controlled deposition and orientation of molecular sized nanoelectromechanical systems (NEMS) on substrates is disclosed. The method comprised: forming a thin layer of polymer coating on a substrate; exposing a selected portion of the thin layer of polymer to alter a selected portion of the thin layer of polymer; forming a suspension of nanostructures in a solvent, wherein the solvent suspends the nanostructures and activates the nanostructures in the solvent for deposition; and flowing a suspension of nanostructures across the layer of polymer in a flow direction; thereby: depositing a nanostructure in the suspension of nanostructures only to the selected portion of the thin layer of polymer coating on the substrate to form a deposited nanostructure oriented in the flow direction. By selectively employing portions of the method above, complex NEMS may be built of simpler NEMSs components.

  17. Computer Code for Nanostructure Simulation

    NASA Technical Reports Server (NTRS)

    Filikhin, Igor; Vlahovic, Branislav

    2009-01-01

    Due to their small size, nanostructures can have stress and thermal gradients that are larger than any macroscopic analogue. These gradients can lead to specific regions that are susceptible to failure via processes such as plastic deformation by dislocation emission, chemical debonding, and interfacial alloying. A program has been developed that rigorously simulates and predicts optoelectronic properties of nanostructures of virtually any geometrical complexity and material composition. It can be used in simulations of energy level structure, wave functions, density of states of spatially configured phonon-coupled electrons, excitons in quantum dots, quantum rings, quantum ring complexes, and more. The code can be used to calculate stress distributions and thermal transport properties for a variety of nanostructures and interfaces, transport and scattering at nanoscale interfaces and surfaces under various stress states, and alloy compositional gradients. The code allows users to perform modeling of charge transport processes through quantum-dot (QD) arrays as functions of inter-dot distance, array order versus disorder, QD orientation, shape, size, and chemical composition for applications in photovoltaics and physical properties of QD-based biochemical sensors. The code can be used to study the hot exciton formation/relation dynamics in arrays of QDs of different shapes and sizes at different temperatures. It also can be used to understand the relation among the deposition parameters and inherent stresses, strain deformation, heat flow, and failure of nanostructures.

  18. Plasmonic Nanostructures for Biosensor Applications

    NASA Astrophysics Data System (ADS)

    Gadde, Akshitha

    Improving the sensitivity of existing biosensors is an active research topic that cuts across several disciplines, including engineering and biology. Optical biosensors are the one of the most diverse class of biosensors which can be broadly categorized into two types based on the detection scheme: label-based and label-free detection. In label-based detection, the target bio-molecules are labeled with dyes or tags that fluoresce upon excitation, indicating the presence of target molecules. Label-based detection is highly-sensitive, capable of single molecule detection depending on the detector type used. One method of improving the sensitivity of label-based fluorescence detection is by enhancement of the emission of the labels by coupling them with metal nanostructures. This approach is referred as plasmon-enhanced fluorescence (PEF). PEF is achieved by increasing the electric field around the nano metal structures through plasmonics. This increased electric field improves the enhancement from the fluorophores which in turn improves the photon emission from the fluorophores which, in turn, improves the limit of detection. Biosensors taking advantage of the plasmonic properties of metal films and nanostructures have emerged an alternative, low-cost, high sensitivity method for detecting labeled DNA. Localized surface plasmon resonance (LSPR) sensors employing noble metal nanostructures have recently attracted considerable attention as a new class of plasmonic nanosensors. In this work, the design, fabrication and characterization of plasmonic nanostructures is carried out. Finite difference time domain (FDTD) simulations were performed using software from Lumerical Inc. to design a novel LSPR structure that exhibit resonance overlapping with the absorption and emission wavelengths of quantum dots (QD). Simulations of a composite Au/SiO2 nanopillars on silicon substrate were performed using FDTD software to show peak plasmonic enhancement at QD emission wavelength

  19. Dynamics of Nanostructures at Surfaces

    SciTech Connect

    Schmid, Andreas K.

    2001-02-28

    Currently, much effort is being devoted to the goal of achieving useful nanotechnologies, which depend on the ability to control and manipulate things on a very small scale. One promising approach to the construction of nanostructures is 'self-assembly', which means that under suitable conditions desired nanostructures might form automatically due to physical and chemical forces. Remarkably, the forces controlling such self-assembly mechanisms are only poorly understood, even though highly successful examples of self-assembly are known in nature (e.g., complex biochemical machinery regularly self-assembles in the conditions inside living cells). This talk will highlight basic measurements of fundamental forces governing the dynamics of nanostructures at prototypical metal surfaces. We use advanced surface microscopy techniques to track the motions of very small structures in real time and up to atomic resolution. One classic example of self-organized nanostructures are networks of surface dislocations (linear crystal defects). The direct observation of thermally activated atomic motions of dislocations in a reconstructed gold surface allows us to measure the forces stabilizing the remarkable long-range order of this nanostructure. In another example, the rapid migration of nano-scale tin crystals deposited on a pure copper surface was traced to an atomic repulsion between tin atoms absorbed on the crystal surface and bronze alloy formed in the footprint of the tin crystals. It is intriguing to consider the clusters as simple chemo-mechanical energy transducers, essentially tiny linear motors built of 100,000 Sn atoms. We can support this view by providing estimates of the power and energy-efficiency of these nano-motors.

  20. Fabrication of zein nanostructure

    NASA Astrophysics Data System (ADS)

    Luecha, Jarupat

    resins. The soft lithography technique was mainly used to fabricate micro and nanostructures on zein films. Zein material well-replicated small structures with the smallest size at sub micrometer scale that resulted in interesting photonic properties. The bonding method was also developed for assembling portable zein microfluidic devices with small shape distortion. Zein-zein and zein-glass microfluidic devices demonstrated sufficient strength to facilitate fluid flow in a complex microfluidic design with no leakage. Aside from the fabrication technique development, several potential applications of this environmentally friendly microfluidic device were investigated. The concentration gradient manipulation of Rhodamine B solution in zein-glass microfluidic devices was demonstrated. The diffusion of small molecules such as fluorescent dye into the wall of the zein microfluidic channels was observed. However, with this formulation, zein microfluidic devices were not suitable for cell culture applications. This pioneer study covered a wide spectrum of the implementation of the two nanotechnology approaches to advance zein biomaterial which provided proof of fundamental concepts as well as presenting some limitations. The findings in this study can lead to several innovative research opportunities of advanced zein biomaterials with broad applications. The information from the study of zein nanocomposite structure allows the packaging industry to develop the low cost biodegradable materials with physical property improvement. The information from the study of the zein microfluidic devices allows agro-industry to develop the nanotechnology-enabled microfluidic sensors fabricated entirely from biodegradable polymer for on-site disease or contaminant detection in the fields of food and agriculture.

  1. An elaboration of the I.L.O. classification of simple pneumoconiosis

    PubMed Central

    Liddell, F. D. K.; Lindars, D. C.

    1969-01-01

    Liddell, F. D. K., and Lindars, D. C. (1969).Brit. J. industr. Med.,26, 89-100. An elaboration of the I.L.O. classification of simple pneumoconiosis. Simple pneumoconiosis in chest radiographs presents a continuum of increasing abnormality. Liddell (1963) introduced a 12-point scale obtained by dividing each of the four I.L.O. categories (International Labour Office, 1959) into one central and two marginal zones. In this system, which has come to be known as the N.C.B. elaboration, readers record for each radiograph the I.L.O. category of choice (0, 1, 2 or 3), followed by an adjacent I.L.O. category if that had been seriously considered; otherwise, the same category is repeated. Very clear normals are denoted as 0/-, and `high' category 3 films as 3/4. This paper reviews the evidence from seven reading trials in which 12 National Coal Board (N.C.B.) film readers have taken part. About 28,000 assessments on a total of well over 2,000 single radiographs have been analysed. (The reading of serial radiographs to assess progression is dealt with elsewhere.) All readers used the elaboration successfully, but they differed in the extents to which they placed films in central and in marginal zones; they were more consistent when preliminary briefing had been given. Film quality had little influence on the use of the zones, except that 0/- tended to be reserved for films of good quality. Despite the variation in the use of the zones, marked improvements accrued from the use of the elaboration in both intra- and inter-observer error for all readers, and for films of poor quality as well as for good films. The validity of expressing simple pneumoconiosis prevalence rates in terms of I.L.O. categories derived from N.C.B. elaboration readings was confirmed. Although the exact widths of the zones along the continuum remain to be determined, all the evidence suggests that they represent steadily increasing abnormality. Thus, the N.C.B. elaboration is a practical procedure which

  2. Plasmonic spectroscopy of metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Ni, Weihai

    The study of the plasmonic spectroscopy of metallic nanostructures is of great interest in nanoscale optics and photonics. Metallic nanostructures exhibit rich optical and electrical properties due to their localized surface plasmons (LSPs, collective charge density oscillations that are confined to metallic nanostructures). They can be widely used in a variety of application areas, such as surface-enhanced Raman scattering (SERS), plasmonic sensing, and metal enhanced fluorescence (MEF). In this thesis, a systematic study on the plasmonic spectroscopy of metallic nanostructures has been presented, both theoretically and experimentally. I will first describe my studies on the plasmonic properties of metallic nanostructures. Specific approaches of modifying the sizes and shapes of Au nanorods have been developed for tailoring their plasmonic properties, including surface plasmon wavelength, absorption, scattering, and extinction cross sections. Single-particle dark-field imaging and spectroscopy have proved that the scattering intensity of overgrown nanorods is larger than that of shortened nanorods from the same starting nanorods. Finite-difference time-domain (FDTD) calculations further show that the scattering-to-extinction ratio increases linearly as a function of the diameter of Au nanorods with a fixed aspect ratio. To obtain a deep understanding on the shape dependence of the localized surface plasmon resonance, I have emplyed FDTD on both Au nanorods and Au nanobipyramids. The results show that, when excited at their LSP wavelengths, Au nanobipyramids exhibit a maximal electric field intensity enhancement that is 3--6 times that of Au nanorods. Au nanorods have been further assembled into chains (end-to-end) and stacks (side-by-side). FDTD calculations have been performed on both Au nanorod chains and stacks with varying gap distances to obtain the dependence of the plasmon shift on the gap distance, which is then used as a plasmonic ruler to estimate the

  3. Elaboration of Bi 2Se 3 by metalorganic chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Giani, A.; Al Bayaz, A.; Foucaran, A.; Pascal-Delannoy, F.; Boyer, A.

    2002-03-01

    For the first time, Bi 2Se 3 thin films were elaborated by metalorganic chemical vapour deposition (MOCVD) using trimethylbismuth (TMBi) and diethylselenium (DESe) as metalorganic sources. The MOCVD elaboration of Bi 2Se 3 was carried out in a horizontal reactor for a substrate temperature ( Tg) varying from 450°C to 500°C, a total hydrogen flow rate DT=3 l min -1, RVI/V ratio >14 and TMBi partial pressure lower than 1.10 -4 atm. By X-ray diffraction and SEM observation, we noticed the polycrystalline structure of the layers typical preferential c-orientation and confirm the hexagonal structure. The microprobe data indicate that the best stoichiometry of Bi 2Se 3 was achieved. These films always displayed n-type conduction, and the maximum value of thermoelectric power α was found to be close to -120 μV/K.

  4. Development of gender differences in depression: an elaborated cognitive vulnerability-transactional stress theory.

    PubMed

    Hankin, B L; Abramson, L Y

    2001-11-01

    Descriptive epidemiological studies are reviewed, showing that the female preponderance in depression begins to emerge around age 13. A developmentally sensitive, elaborated cognitive vulnerability-transactional stress model of depression is proposed to explain the "big fact" of the emergence of the gender difference in depression. The elaborated causal chain posits that negative events contribute to initial elevations of general negative affect. Generic cognitive vulnerability factors then moderate the likelihood that the initial negative affect will progress to full-blown depression. Increases in depression can lead transactionally to more self-generated dependent negative life events and thus begin the causal chain again. Evidence is reviewed providing preliminary support for the model as an explanation for the development of the gender difference in depression during adolescence. PMID:11726071

  5. The EHD protein Past1 controls postsynaptic membrane elaboration and synaptic function

    PubMed Central

    Koles, Kate; Messelaar, Emily M.; Feiger, Zachary; Yu, Crystal J.; Frank, C. Andrew; Rodal, Avital A.

    2015-01-01

    Membranes form elaborate structures that are highly tailored to their specialized cellular functions, yet the mechanisms by which these structures are shaped remain poorly understood. Here, we show that the conserved membrane-remodeling C-terminal Eps15 Homology Domain (EHD) protein Past1 is required for the normal assembly of the subsynaptic muscle membrane reticulum (SSR) at the Drosophila melanogaster larval neuromuscular junction (NMJ). past1 mutants exhibit altered NMJ morphology, decreased synaptic transmission, reduced glutamate receptor levels, and a deficit in synaptic homeostasis. The membrane-remodeling proteins Amphiphysin and Syndapin colocalize with Past1 in distinct SSR subdomains and collapse into Amphiphysin-dependent membrane nodules in the SSR of past1 mutants. Our results suggest a mechanism by which the coordinated actions of multiple lipid-binding proteins lead to the elaboration of increasing layers of the SSR and uncover new roles for an EHD protein at synapses. PMID:26202464

  6. Elaboration and Characterization of High Silica ZSM-5 and Mordenite Solid Microporous Materials

    NASA Astrophysics Data System (ADS)

    Khemaissia, Sihem; Nibou, Djamel; Amokrane, Samira; Lebaili, Nemcha

    In this study, we were interested to use a hydrothermally method of elaboration of ZSM-5 and Mordenite solid microporous materials. This method is based on crystallization of amorphous gels composed of silicon and aluminium solutions. The elaborations were carried out in stainless steel Teflon lined autoclave over different operation conditions: heating temperature, contact time, pH and agitation of the reactional medium. After crystallization, samples were characterized by several techniques as X ray diffraction, scanning microscopy, infrared spectroscopy. The used method was allowed the obtaining of pure phases of solids belonging to ZSM-5 and mordenite structures respectively. The crystal growth environment during nucleation and crystallization was occurred at the liquid-gel interface in the dispersed gel-solution mixtures. The composition of these structures was found as high silica zeolites.

  7. Differential-associative processing or example elaboration: Which strategy is best for learning the definitions of related and unrelated concepts?

    PubMed Central

    Hannon, Brenda

    2013-01-01

    Definitions of related concepts (e.g., genotype–phenotype) are prevalent in introductory classes. Consequently, it is important that educators and students know which strategy(s) work best for learning them. This study showed that a new comparative elaboration strategy, called differential-associative processing, was better for learning definitions of related concepts than was an integrative elaborative strategy, called example elaboration. This outcome occurred even though example elaboration was administered in a naturalistic way (Experiment 1) and students spent more time in the example elaboration condition learning (Experiments 1, 2, 3), and generating pieces of information about the concepts (Experiments 2 and 3). Further, with unrelated concepts (morpheme-fluid intelligence), performance was similar regardless if students used differential-associative processing or example elaboration (Experiment 3). Taken as a whole, these results suggest that differential-associative processing is better than example elaboration for learning definitions of related concepts and is as good as example elaboration for learning definitions of unrelated concepts. PMID:24347814

  8. Effects of Forward and Backward Contextual Elaboration on Lexical Inferences: Evidence from a Semantic Relatedness Judgment Task

    ERIC Educational Resources Information Center

    Hamada, Akira

    2015-01-01

    Three experiments examined whether the process of lexical inferences differs according to the direction of contextual elaboration using a semantic relatedness judgment task. In Experiment 1, Japanese university students read English sentences where target unknown words were semantically elaborated by prior contextual information (forward lexical…

  9. Standard Setting and Risk Preference: An Elaboration of the Theory of Achievement Motivation and an Empirical Test

    ERIC Educational Resources Information Center

    Kuhl, Julius

    1978-01-01

    A formal elaboration of the original theory of achievement motivation (Atkinson, 1957; Atkinson & Feather, 1966) is proposed that includes personal standards as determinants of motivational tendencies. The results of an experiment are reported that examines the validity of some of the implications of the elaborated model proposed here. (Author/RK)

  10. [Determination of the ulcer area in the diabetic foot syndrome using elaborated programe supply].

    PubMed

    Horobeĭko, M B; Nastenko, D V

    2014-02-01

    Efficacy of area estimation of the ulcer or the wound defect, using the programe-apparatus system "WoundViewer", elaborated by specialists from Ukrainian scientific-practical centre and National technical university of Ukraine "KPI", was studied. The programe is based on objective estimation with a real scale viewing of the wound area and permit to measure area of wound, owing any form. The programe is highly effective during the process of dynamical estimation of the treatment quality. PMID:24923117

  11. Concise, aromatization-based approach to an elaborate C2-symmetric pyrenophane.

    PubMed

    Nandaluru, Penchal Reddy; Dongare, Prateek; Kraml, Christina M; Pascal, Robert A; Dawe, Louise N; Thompson, David W; Bodwell, Graham J

    2012-08-11

    A very short synthesis (5 steps), the crystal structure and resolution of an elaborate, inherently chiral [n](1,6)pyrenophane is reported. The synthesis hinges upon two very productive events: a multicomponent reaction and an unprecedented double-McMurry/valence isomerization/dehydrogenation step. Aromatization reactions are involved in the formation of all four of the rings of the pyrene system. PMID:22760162

  12. Composite materials formed with anchored nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  13. Chemical Sensors Based on Metal Oxide Nanostructures

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Xu, Jennifer C.; Evans, Laura J.; VanderWal, Randy L.; Berger, Gordon M.; Kulis, Mike J.; Liu, Chung-Chiun

    2006-01-01

    This paper is an overview of sensor development based on metal oxide nanostructures. While nanostructures such as nanorods show significan t potential as enabling materials for chemical sensors, a number of s ignificant technical challenges remain. The major issues addressed in this work revolve around the ability to make workable sensors. This paper discusses efforts to address three technical barriers related t o the application of nanostructures into sensor systems: 1) Improving contact of the nanostructured materials with electrodes in a microse nsor structure; 2) Controling nanostructure crystallinity to allow co ntrol of the detection mechanism; and 3) Widening the range of gases that can be detected by using different nanostructured materials. It is concluded that while this work demonstrates useful tools for furt her development, these are just the beginning steps towards realizati on of repeatable, controlled sensor systems using oxide based nanostr uctures.

  14. Cue strength as a moderator of the testing effect: the benefits of elaborative retrieval.

    PubMed

    Carpenter, Shana K

    2009-11-01

    The current study explored the elaborative retrieval hypothesis as an explanation for the testing effect: the tendency for a memory test to enhance retention more than restudying. In particular, the retrieval process during testing may activate elaborative information related to the target response, thereby increasing the chances that activation of any of this information will facilitate later retrieval of the target. In a test of this view, participants learned cue-target pairs, which were strongly associated (e.g., Toast: Bread) or weakly associated (e.g., Basket: Bread), through either a cued recall test (Toast: _____) or a restudy opportunity (Toast: Bread). A final test requiring free recall of the targets revealed that tested items were retained better than restudied items, and although strong cues facilitated recall of tested items initially, items recalled from weak cues were retained better over time, such that this advantage was eliminated or reversed at the time of the final test. Restudied items were retained at similar rates on the final test regardless of the strength of the cue-target relationship. These results indicate that the activation of elaborative information-which would occur to a greater extent during testing than restudying--may be one mechanism that underlies the testing effect. PMID:19857026

  15. Contributions of attention and elaboration to associative encoding in young and older adults.

    PubMed

    Kamp, Siri-Maria; Zimmer, Hubert D

    2015-08-01

    Episodic memory declines during healthy aging, with a particular reduction in the ability to encode associations. We investigated the role of alternating attentional focus between two items of a pair in order to generate associative links, as well as working memory based elaborative processes in this age-related memory deficit. While their eye gaze behavior and ERPs were recorded, 19 young and 22 elderly (64-79 years) participants used interactive imagery to encode pairs of spatially separated objects. In a subsequent recognition test, older adults showed a larger reduction in associative than item memory, relative to young adults. For both age groups the number of eye gaze transitions between objects at encoding was correlated with associative recognition performance, suggesting that alternating attentional focus between items aids the generation of relational links necessary to encode associative memories. However, the relative time course of eye gaze transitions over the encoding interval for trials that were subsequently retrieved vs. forgotten differed between age groups. Furthermore, the ERPs of older adults exhibited strongly reduced frontal slow wave "subsequent memory effects", suggesting that they engaged to a lesser extent in working memory-based elaboration of the associative link. Based on these results, we propose that older adults exhibit a reduced tendency to generate and elaborate on internal representations of inter-item associative links. Rather, they use a less effective encoding strategy that disproportionally relies on the external stimulus display, resulting in lower associative memory performance. PMID:26115601

  16. Estimation of the intrinsic stresses in alpha-alumina in relation with its elaboration mode

    SciTech Connect

    Boumaza, A.; Djelloul, A.

    2010-05-15

    The specific signatures of alpha-Al{sub 2}O{sub 3} by Fourier transform infrared (FTIR) spectroscopy were investigated to estimate the intrinsic stress in this compound according to its elaboration mode. Thus, alpha-alumina was prepared either by calcination of boehmite or gibbsite and also generated by oxidation of a metallic FeCrAl alloy. FTIR results were mainly supported by X-ray diffraction (XRD) patterns that allowed to determine the crystallite size and the strain in the various alpha aluminas. Moreover, the infrared peak at 378.7 cm{sup -1} was used as a reference for stress free alpha-alumina and the shift of this peak allowed to estimate intrinsic stresses, which were related to the morphology and to the specific surface area of aluminas according to their elaboration mode. These interpretations were confirmed by results obtained by cathodoluminescence experiments. - Graphical abstract: The infrared peak at 378.7 cm{sup -1} was used as a reference for stress free alpha-alumina and the shift of this peak allowed to estimate intrinsic stresses, which were related to the morphology and to the specific surface area of aluminas according to their elaboration mode.

  17. Raman Studies of Carbon Nanostructures

    NASA Astrophysics Data System (ADS)

    Jorio, Ado; Souza Filho, Antonio G.

    2016-07-01

    This article reviews recent advances on the use of Raman spectroscopy to study and characterize carbon nanostructures. It starts with a brief survey of Raman spectroscopy of graphene and carbon nanotubes, followed by recent developments in the field. Various novel topics, including Stokes–anti-Stokes correlation, tip-enhanced Raman spectroscopy in two dimensions, phonon coherence, and high-pressure and shielding effects, are presented. Some consequences for other fields—quantum optics, near-field electromagnetism, archeology, materials and soil sciences—are discussed. The review ends with a discussion of new perspectives on Raman spectroscopy of carbon nanostructures, including how this technique can contribute to the development of biotechnological applications and nanotoxicology.

  18. Nanostructured materials for water desalination.

    PubMed

    Humplik, T; Lee, J; O'Hern, S C; Fellman, B A; Baig, M A; Hassan, S F; Atieh, M A; Rahman, F; Laoui, T; Karnik, R; Wang, E N

    2011-07-22

    Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity. PMID:21680966

  19. Topology optimization of piezoelectric nanostructures

    NASA Astrophysics Data System (ADS)

    Nanthakumar, S. S.; Lahmer, Tom; Zhuang, Xiaoying; Park, Harold S.; Rabczuk, Timon

    2016-09-01

    We present an extended finite element formulation for piezoelectric nanobeams and nanoplates that is coupled with topology optimization to study the energy harvesting potential of piezoelectric nanostructures. The finite element model for the nanoplates is based on the Kirchoff plate model, with a linear through the thickness distribution of electric potential. Based on the topology optimization, the largest enhancements in energy harvesting are found for closed circuit boundary conditions, though significant gains are also found for open circuit boundary conditions. Most interestingly, our results demonstrate the competition between surface elasticity, which reduces the energy conversion efficiency, and surface piezoelectricity, which enhances the energy conversion efficiency, in governing the energy harvesting potential of piezoelectric nanostructures.

  20. Coherent acoustic phonons in nanostructures

    NASA Astrophysics Data System (ADS)

    Dekorsy, T.; Taubert, R.; Hudert, F.; Bartels, A.; Habenicht, A.; Merkt, F.; Leiderer, P.; Köhler, K.; Schmitz, J.; Wagner, J.

    2008-02-01

    Phonons are considered as a most important origin of scattering and dissipation for electronic coherence in nanostructures. The generation of coherent acoustic phonons with femtosecond laser pulses opens the possibility to control phonon dynamics in amplitude and phase. We demonstrate a new experimental technique based on two synchronized femtosecond lasers with GHz repetition rate to study the dynamics of coherently generated acoustic phonons in semiconductor heterostructures with high sensitivity. High-speed synchronous optical sampling (ASOPS) enables to scan a time-delay of 1 ns with 100 fs time resolution with a frequency in the kHz range without a moving part in the set-up. We investigate the dynamics of coherent zone-folded acoustic phonons in semiconductor superlattices (GaAs/AlAs and GaSb/InAs) and of coherent vibration of metallic nanostructures of non-spherical shape using ASOPS.

  1. Nanorice: a new hybrid nanostructure

    NASA Astrophysics Data System (ADS)

    Nordlander, P.; Brandl, D.; Le, F.; Wang, H.; Halas, N. J.

    2006-03-01

    The plasmon hybridization method [1] is applied to nanorice, a new metallic nanostructure which combines the properties of two popular tunable plasmonic nanoparticle geometries: nanorods and nanoshells. The particle consists of a prolate spheroidal dielectric core and a thin metallic shell, bearing a remarkable resemblance to a rice grain. The nanorice particle shows far greater geometric tunability of the optical resonance, larger local field intensity enhancements and far greater sensitivity as a surface plasmon resonance (SPR) nanosensor than any previously reported dielectric-metal nanostructure. The tunability of the nanorice particle arises from the interaction of primitive plasmons associated with the inner and outer surfaces of the shell. The results from plasmon hybridization are compared to FDTD simulations. [1] E. Prodan and P. Nordlander, J. Chem. Phys. 120(2004)5444-5454

  2. Advances in CZTS thin films and nanostructured

    NASA Astrophysics Data System (ADS)

    Ali, N.; Ahmed, R.; Bakhtiar-Ul-Haq; Shaari, A.

    2015-06-01

    Already published data for the optical band gap (Eg) of thin films and nanostructured copper zinc tin sulphide (CZTS) have been reviewed and combined. The vacuum (physical) and non-vacuum (chemical) processes are focused in the study for band gap comparison. The results are accumulated for thin films and nanostructured in different tables. It is inferred from the re- view that the nanostructured material has plenty of worth by engineering the band gap for capturing the maximum photons from solar spectrum.

  3. Sintering and ripening resistant noble metal nanostructures

    DOEpatents

    van Swol, Frank B; Song, Yujiang; Shelnutt, John A; Miller, James E; Challa, Sivakumar R

    2013-09-24

    Durable porous metal nanostructures comprising thin metal nanosheets that are metastable under some conditions that commonly produce rapid reduction in surface area due to sintering and/or Ostwald ripening. The invention further comprises the method for making such durable porous metal nanostructures. Durable, high-surface area nanostructures result from the formation of persistent durable holes or pores in metal nanosheets formed from dendritic nanosheets.

  4. Thermoelectric effects in graphene nanostructures.

    PubMed

    Dollfus, Philippe; Hung Nguyen, Viet; Saint-Martin, Jérôme

    2015-04-10

    The thermoelectric properties of graphene and graphene nanostructures have recently attracted significant attention from the physics and engineering communities. In fundamental physics, the analysis of Seebeck and Nernst effects is very useful in elucidating some details of the electronic band structure of graphene that cannot be probed by conductance measurements alone, due in particular to the ambipolar nature of this gapless material. For applications in thermoelectric energy conversion, graphene has two major disadvantages. It is gapless, which leads to a small Seebeck coefficient due to the opposite contributions of electrons and holes, and it is an excellent thermal conductor. The thermoelectric figure of merit ZT of a two-dimensional (2D) graphene sheet is thus very limited. However, many works have demonstrated recently that appropriate nanostructuring and bandgap engineering of graphene can concomitantly strongly reduce the lattice thermal conductance and enhance the Seebeck coefficient without dramatically degrading the electronic conductance. Hence, in various graphene nanostructures, ZT has been predicted to be high enough to make them attractive for energy conversion. In this article, we review the main results obtained experimentally and theoretically on the thermoelectric properties of graphene and its nanostructures, emphasizing the physical effects that govern these properties. Beyond pure graphene structures, we discuss also the thermoelectric properties of some hybrid graphene structures, as graphane, layered carbon allotropes such as graphynes and graphdiynes, and graphene/hexagonal boron nitride heterostructures which offer new opportunities. Finally, we briefly review the recent activities on other atomically thin 2D semiconductors with finite bandgap, i.e. dichalcogenides and phosphorene, which have attracted great attention for various kinds of applications, including thermoelectrics. PMID:25779989

  5. Insulating oxide surfaces and nanostructures

    NASA Astrophysics Data System (ADS)

    Goniakowski, Jacek; Noguera, Claudine

    2016-03-01

    This contribution describes some peculiarities of the science of oxide surfaces and nanostructures and proposes a simple conceptual scheme to understand their electronic structure, in the spirit of Jacques Friedel's work. Major results on the effects of non-stoichiometry and polarity are presented, for both semi-infinite surfaces and ultra-thin films, and promising lines of research for the near future are sketched. xml:lang="fr"

  6. Functional Properties of Nanostructured Materials

    NASA Astrophysics Data System (ADS)

    Kassing, Rainer; Petkov, Plamen; Kulisch, Wilhelm; Popov, Cyril

    This book, based on the lectures and contributions of the NATO ASI on "Functional Properties of Nanostructured Materials", gives a broad overview on this topic, as it combines basic theoretical articles, papers dealing with experimental techniques, and contributions on advanced and up-to-date applications in fields such as microelectronics, optoelectronics, electrochemistry, sensorics, and biotechnology. In addition, it presents an interdisciplinary approach since the authors came from such different fields as physics, chemistry, engineering, materials science and biology.

  7. Ultrasonic approach for surface nanostructuring.

    PubMed

    Skorb, Ekaterina V; Möhwald, Helmuth

    2016-03-01

    The review is about solid surface modifications by cavitation induced in strong ultrasonic fields. The topic is worth to be discussed in a special issue of surface cleaning by cavitation induced processes since it is important question if we always find surface cleaning when surface modifications occur, or vice versa. While these aspects are extremely interesting it is important for applications to follow possible pathways during ultrasonic treatment of the surface: (i) solely cleaning; (ii) cleaning with following surface nanostructuring; and (iii) topic of this particular review, surface modification with controllably changing its characteristics for advanced applications. It is important to know what can happen and which parameters should be taking into account in the case of surface modification when actually the aim is solely cleaning or aim is surface nanostructuring. Nanostructuring should be taking into account since is often accidentally applied in cleaning. Surface hydrophilicity, stability to Red/Ox reactions, adhesion of surface layers to substrate, stiffness and melting temperature are important to predict the ultrasonic influence on a surface and discussed from these points for various materials and intermetallics, silicon, hybrid materials. Important solid surface characteristics which determine resistivity and kinetics of surface response to ultrasonic treatment are discussed. It is also discussed treatment in different solvents and presents in solution of metal ions. PMID:26382299

  8. Photoinduced magnetic force between nanostructures

    NASA Astrophysics Data System (ADS)

    Guclu, Caner; Tamma, Venkata Ananth; Wickramasinghe, Hemantha Kumar; Capolino, Filippo

    2015-12-01

    Photoinduced magnetic force between nanostructures, at optical frequencies, is investigated theoretically. Till now optical magnetic effects were not used in scanning probe microscopy because of the vanishing natural magnetism with increasing frequency. On the other hand, artificial magnetism in engineered nanostructures led to the development of measurable optical magnetism. Here two examples of nanoprobes that are able to generate strong magnetic dipolar fields at optical frequency are investigated: first, an ideal magnetically polarizable nanosphere and then a circular cluster of silver nanospheres that has a looplike collective plasmonic resonance equivalent to a magnetic dipole. Magnetic forces are evaluated based on nanostructure polarizabilities, i.e., induced magnetic dipoles, and magnetic-near field evaluations. As an initial assessment on the possibility of a magnetic nanoprobe to detect magnetic forces, we consider two identical magnetically polarizable nanoprobes and observe magnetic forces on the order of piconewtons, thereby bringing it within detection limits of conventional atomic force microscopes at ambient pressure and temperature. The detection of magnetic force is a promising method in studying optical magnetic transitions that can be the basis of innovative spectroscopy applications.

  9. Precise replication of antireflective nanostructures from biotemplates

    NASA Astrophysics Data System (ADS)

    Gao, Hongjun; Liu, Zhongfan; Zhang, Jin; Zhang, Guoming; Xie, Guoyong

    2007-03-01

    The authors report herein a new type of nanonipple structures on the cicada's eye and the direct structural replication of the complex micro- and nanostructures for potential functional emulation. A two-step direct molding process is developed to replicate these natural micro- and nanostructures using epoxy resin with high fidelity, which demonstrates a general way of fabricating functional nanostructures by direct replication of natural biotemplates via a suitable physicochemical process. Measurements of spectral reflectance showed that this kind of replicated nanostructure has remarkable antireflective property, suggestive of its potential applications to optical devices.

  10. Processing Nanostructured Sensors Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; VanderWal, Randall L.; Evans, Laura J.; Xu, Jennifer C.

    2010-01-01

    Standard microfabrication techniques can be implemented and scaled to help assemble nanoscale microsensors. Currently nanostructures are often deposited onto materials primarily by adding them to a solution, then applying the solution in a thin film. This results in random placement of the nanostructures with no controlled order, and no way to accurately reproduce the placement. This method changes the means by which microsensors with nanostructures are fabricated. The fundamental advantage to this approach is that it enables standard microfabrication techniques to be applied in the repeated manufacture of nanostructured sensors on a microplatform.

  11. Anchored nanostructure materials and method of fabrication

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  12. Synthesis of Silver Nanostructures by Multistep Methods

    PubMed Central

    Zhang, Tong; Song, Yuan-Jun; Zhang, Xiao-Yang; Wu, Jing-Yuan

    2014-01-01

    The shape of plasmonic nanostructures such as silver and gold is vital to their physical and chemical properties and potential applications. Recently, preparation of complex nanostructures with rich function by chemical multistep methods is the hotspot of research. In this review we introduce three typical multistep methods to prepare silver nanostructures with well-controlled shapes, including the double reductant method, etching technique and construction of core-shell nanostructures. The growth mechanism of double the reductant method is that different favorable facets of silver nanocrystals are produced in different reductants, which can be used to prepare complex nanostructures such as nanoflags with ultranarrow resonant band bandwidth or some silver nanostructures which are difficult to prepare using other methods. The etching technique can selectively remove nanoparticles to achieve the aim of shape control and is widely used for the synthesis of nanoflowers and hollow nanostructures. Construction of core-shell nanostructures is another tool to control shape and size. The three methods can not only prepare various silver nanostructures with well-controlled shapes, which exhibit unique optical properties, such as strong surface-enhanced Raman scattering (SERS) signal and localized surface plasmon resonance (LSPR) effect, but also have potential application in many areas. PMID:24670722

  13. Nanostructures having crystalline and amorphous phases

    SciTech Connect

    Mao, Samuel S; Chen, Xiaobo

    2015-04-28

    The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.

  14. Nanostructures created by interfered femtosecond laser

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Chang, Yun-Ching; Yao, Jimmy; Luo, Claire; Yin, Shizhuo; Ruffin, Paul; Brantley, Christina; Edwards, Eugene

    2011-10-01

    The method by applying the interfered femtosecond laser to create nanostructured copper (Cu) surface has been studied. The nanostructure created by direct laser irradiation is also realized for comparison. Results show that more uniform and finer nanostructures with sphere shape and feature size around 100 nm can be induced by the interfered laser illumination comparing with the direct laser illumination. This offers an alternative fabrication approach that the feature size and the shape of the laser induced metallic nanostructures can be highly controlled, which can extremely improve its performance in related application such as the colorized metal, catalyst, SERS substrate, and etc.

  15. Zinc oxide nanostructures and nanoengineering

    NASA Astrophysics Data System (ADS)

    Banerjee, Debasish

    ZnO is a large band-gap (3.37 eV) semiconductor, a potentially important material for numerous optoelectronic applications. Nanostructures, by definition are the structures having at least one dimension between 1--100 nm. In this thesis we will investigate a brief account of the strategies to grow ZnO nanostructures. Since invariably nanomaterial properties tend to change significantly during scale-up from development on limited volume equipment. Goal of this study is to demonstrate a practical technique which is able to synthesize large quantities of nanowires while keeping the unique properties of nano-sized materials. Using ZnO as an example, we discussed a strategy to produce nanowires in gram quantity. Ability to define position, size, and density of nanostructures on surfaces enable detailed studies of the properties of individual sites as well as collective properties of the assembly. These periodic structures are usually manufactured using electron beam lithography, photolithography, or x-ray lithography techniques. These methods allow fabrication of nanostructures and provide highly reproducible results. However, they are mostly not scalable to large areas, and are limited by a multistage, time-consuming, and expensive preparation procedure. We described an unique technique combining nanosphere self-assembly lithography and vapor-liquid-solid (VLS) approach of fabricating periodic array of catalyst dots in various geometry and subsequently grow vertically aligned ZnO nanowires in a large area hoping to achieve enhanced ultraviolet lasing and many other photonic devices. ZnO being a transparent conducting oxide, the fabrication of ZnO field emitters can be easily integrated with ITO and ZnO thin film fabrication process. Thus a low cost solution for fabrication of field emission display can be realized using ZnO nanowires as field emitters. There have been several demonstrations of using ZnO nanowires as field emitters. However no significant improvement in

  16. WO3 nano-spheres into W18O49 one-dimensional nano-structures through thermal annealing.

    PubMed

    Mwakikunga, B W; Sideras-Haddad, E; Arendse, C; Witcomb, M J; Forbes, A

    2009-05-01

    We elaborate the size controlled synthesis of nano-spheres and nano-crystals of WO3 by ultrasonic spray pyrolysis. The as-deposited particles are predominantly spherical in shape and tend to exhibit less agglomeration and a decrease in diameter as the process temperature is increased. Characterization was carried out using transmission (TEM) and scanning (SEM) electron microscopy, energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). One-dimensional nano-structures with the highest yield of WOx nano-wires were observed in a sample synthesized at 500 degrees C but only after thermal annealing of this sample at 500 degrees C for 17 hour in flowing argon. XRD revealed a high deficiency in oxygen in all samples suggesting that the nano-structures are transformed to sub-oxides of tungsten. Micro-diffraction patterns of a typical nano-wire reveal the monoclinic phase of W18O49. PMID:19453005

  17. Utilizing coupled-oscillator photophysics to elaborate chromophores with exceptional molecular hyperpolarizabilities

    NASA Astrophysics Data System (ADS)

    Uyeda, H. T.; Miloradovic, Ivan R.; Zhao, Yuxia; Wostyn, Kurt; Asselberghs, Inge; Clays, Koen J.; Persoons, Andre P.; Therien, Michael J.

    2003-11-01

    The syntheses and electrooptic properties of a family of nonlinear optical chromophores are described. Typically, these species feature an ethyne-elaborated, highly polarizable porphyrinic component, and metal polypyridyl complexes that serve as integral donor and acceptor elements. The frequency dependence of the dynamic hyperpolarizability of a wide-range of these chromophores, that vary widely with respect to their electronic structure, was determined from hyper-Rayleigh light scattering (HRS) measurements carried out at fundamental incident irradiation wavelengths (λinc) of 830, 1064, and 1300 nm. These data show that: (i) Coupled oscillator photophysics and metal-mediated cross-coupling can be exploited to elaborate high βλ supermolecules that exhibit significant excited-state electronic communication between their respective pigment building blocks; (ii) High-stability metal polypyridyl compounds constitute an attractive alternative to electron releasing dialkyl- and diarylamino groups, the most commonly used donor moieties in a wide-range of established NLO dyes, and long-recognized to be the moiety that often limits the thermal stability of such compounds; (iii) This design strategy clearly enables ready elaboration of extraordinarily large βλ chromophores at telecommunication-relevant wavelengths; and (iv) Multiple charge-transfer (CT) transitions within a single chromophore can be designed to have transition dipole moments of the same or opposite sign; because the sign of the resonance enhancement factor is frequency dependent, appropriate engineering of the relative contributions of these CT states at a given wavelength provides a new means to regulate the magnitude of dynamic hyperpolarizabilities.

  18. Peripheral androgen receptors sustain the acrobatics and fine motor skill of elaborate male courtship.

    PubMed

    Fuxjager, Matthew J; Longpre, Kristy M; Chew, Jennifer G; Fusani, Leonida; Schlinger, Barney A

    2013-09-01

    Androgenic hormones regulate many aspects of animal social behavior, including the elaborate display routines on which many species rely for advertisement and competition. One way that this might occur is through peripheral effects of androgens, particularly on skeletal muscles that control complex movements and postures of the body and its limbs. However, the specific contribution of peripheral androgen-muscle interactions to the performance of elaborate behavioral displays in the natural world has never been examined. We study this issue in one of the only natural physiological models of animal acrobatics: the golden-collared manakin (Manacus vitellinus). In this tropical bird, males compete with each other and court females by producing firecracker-like wing- snaps and by rapidly dancing among saplings over the forest floor. To test how activation of peripheral androgen receptors (AR) influences this display, we treat reproductively active adult male birds with the peripherally selective antiandrogen bicalutamide (BICAL) and observe the effects of this manipulation on male display performance. We not only validate the peripheral specificity of BICAL in this species, but we also show that BICAL treatment reduces the frequency with which adult male birds perform their acrobatic display maneuvers and disrupts the overall structure and fine-scale patterning of these birds' main complex wing-snap sonation. In addition, this manipulation has no effect on the behavioral metrics associated with male motivation to display. Together, our findings help differentiate the various effects of peripheral and central AR on the performance of a complex sociosexual behavioral phenotype by indicating that peripheral AR can optimize the motor skills necessary for the production of an elaborate animal display. PMID:23782945

  19. Vertically aligned nanostructure scanning probe microscope tips

    SciTech Connect

    Guillorn, Michael A.; Ilic, Bojan; Melechko, Anatoli V.; Merkulov, Vladimir I.; Lowndes, Douglas H.; Simpson, Michael L.

    2006-12-19

    Methods and apparatus are described for cantilever structures that include a vertically aligned nanostructure, especially vertically aligned carbon nanofiber scanning probe microscope tips. An apparatus includes a cantilever structure including a substrate including a cantilever body, that optionally includes a doped layer, and a vertically aligned nanostructure coupled to the cantilever body.

  20. Processing of Nanostructured Devices Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W (Inventor); Xu, Jennifer C (Inventor); Evans, Laura J (Inventor); Kulis, Michael H (Inventor); Berger, Gordon M (Inventor); Vander Wal, Randall L (Inventor)

    2014-01-01

    Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response.

  1. Nanostructuring and ductility of crystals under compression

    NASA Astrophysics Data System (ADS)

    Magomedov, M. N.

    2016-05-01

    Nanostructuring of crystals into domains under uniform compression, the ductility of a solid nanostructure under pressure, and the bimodal distribution of domain size are explained based on the dependence of the surface energy and surface pressure on the shape, size, and density of a nanocrystal.

  2. Metal oxide nanostructures with hierarchical morphology

    DOEpatents

    Ren, Zhifeng; Lao, Jing Yu; Banerjee, Debasish

    2007-11-13

    The present invention relates generally to metal oxide materials with varied symmetrical nanostructure morphologies. In particular, the present invention provides metal oxide materials comprising one or more metallic oxides with three-dimensionally ordered nanostructural morphologies, including hierarchical morphologies. The present invention also provides methods for producing such metal oxide materials.

  3. A real-time data acquisition and elaboration system for instabilities control in the FTU tokamak

    NASA Astrophysics Data System (ADS)

    Alessi, E.; Boncagni, L.; Galperti, C.; Marchetto, C.; Nowak, S.; Sozzi, C.; Apruzzese, G.; Bin, W.; Belli, F.; Botrugno, A.; Bruschi, A.; Cirant, S.; D‧Antona, G.; Davoudi, M.; Figini, L.; Ferrero, R.; Gabellieri, L.; Garavaglia, S.; Granucci, G.; Grosso, A.; Lazzaro, E.; Moro, A.; Mellera, V.; Minelli, D.; Panella, M.; Piergotti, V.; Platania, P.; Ramogida, G.; Rocchi, G.; Sibio, A.; Tilia, B.; Tudisco, O.

    2013-08-01

    A real-time data acquisition and elaboration system is being implemented to control the new ECH launcher recently installed at FTU (Frascati Tokamak Upgrade). The system is aimed at controlling different kinds of magnetohydrodynamic instabilities, in particular the deleterious 3/2 and 2/1 (neoclassical) tearing modes, (N)TM, and the saw teeth period in order to prevent the seeding of NTMs. The complete system is presented here together with preliminary offline and real-time tests. 2001 Elsevier Science.

  4. An Elaborate Supramolecular Assembly for a Smart Nanodevice for Ratiometric Molecular Recognition and Logic Gates.

    PubMed

    Xie, Yu-Jie; Wu, Wen-Yu; Chen, Hao; Li, Xiang; Zhang, Hao-Li; Liu, Liang-Liang; Shao, Xing-Xin; Shan, Chang-Fu; Liu, Wei-Sheng; Tang, Yu

    2016-06-01

    Ingenious approaches to supramolecular assembly for fabricating smart nanodevices is one of the more significant topics in nanomaterials research. Herein, by using surface quaternized cationic carbon dots (CDots) as the assembly and fluorescence platform, anionic sulfonatocalix[4]arene with modifiable lower and upper rims as a connector, as well as in situ coordination of Tb(3+) ions, we propose an elaborate supramolecular assembly strategy for the facile fabrication of a multifunctional nanodevice. The dynamic equilibrium characteristics of the supramolecular interaction can eventually endow this nanodevice with functions of fluorescent ratiometric molecular recognition and as a nano-logic gate with two output channels. PMID:27106796

  5. [Simplification and over-elaboration in English translation of traditional Chinese medicine].

    PubMed

    Shen, Xiao-Xiong

    2007-09-01

    Aiming at the problem concerning simplification or over-elaboration in the English translation of TCM, which exists in the most common teaching materials both at home and abroad, the author indicated, by way of illustration, that the English translation of TCM should match the international teaching requirement for TCM: popularized, simple and clear, without superfluities, recommended for applying Chinese Pinyin, rich and colorful in both text and illustrative atlases. Meanwhile, the English translations should be faithful to their origi-nals, conform to the characteristics of TCM and vulgarity should be avoided. PMID:17969905

  6. Formation and Characterization of Carbon and Ceramic Nanostructures

    NASA Astrophysics Data System (ADS)

    Huczko, Andrzej; Bystrzejewski, Michał; Lange, Hubert; Baranowski, Piotr

    Different carbon and ceramic nanostructures (nanotubes, nanowires, nanofibres, nanorods, and nanoencapsulates) have great potential for improving our understanding of the fundamental concepts of the roles of both dimensionality and size on physical properties, as well as for many potential applications. Carbon nanotubes (CNTs) were produced in carbon arc plasma using different starting carbons, as the anode material. Low-graphitized carbons (including carbon black) proved to be much more efficient comparing to the regular graphite material. The optical emission and absorption spectroscopy was used for spectral diagnostics of the carbon arc. Carbon arc was also used to produce carbon onions containing magnetic nanocrystallites (Fe and magnetic alloys) in the core. The process was optimized and the procedure to isolate encapsulates was elaborated. Carbon nanocapsules containing Fe were also obtained via combustion synthesis from mixtures NaN3-C6Cl6-Ferrocene. This technique also proved to be very efficient to produce silicon carbide nanowires from Teflon (PTFE) and different reductants (CaSi2, Si). The protocol to isolate and efficiently purify the final product (up to 98 wt%) was proposed.

  7. Vicinal surfaces for functional nanostructures.

    PubMed

    Tegenkamp, Christoph

    2009-01-01

    Vicinal surfaces are currently the focus of research. The regular arrangements of atomic steps on a mesoscopic scale reveal the possibility to functionalize these surfaces for technical applications, e.g. nanowires, catalysts, etc. The steps of the vicinal surface are well-defined defect structures of atomic size for nucleation of low-dimensional nanostructures. The concentration and therefore the coupling between the nanostructures can be tuned over a wide range by simply changing the inclination angle of the substrate. However, the coupling of these nano-objects to the substrate is just as important in controlling their electronic or chemical properties and making a functionality useable. On the basis of stepped insulating films, these aspects are fulfilled and will be considered in the first part of this review. Recent results for the epitaxial growth of wide bandgap insulating films (CaF(2), MgO, NaCl, BaSrO) on metallic and semiconducting vicinal substrates (Si(100), Ge(100), Ag(100)) will be presented. The change of the electronic structure, the adsorption behavior as well as the kinetics and energetics of color centers in the presence of steps is discussed. The successful bridging of the gap between the atomic and mesoscopic world, i.e. the functionalization of vicinal surfaces by nanostructures, is demonstrated in the second part by metal adsorption on semiconducting surfaces. For (sub)monolayer coverage these systems have in common that the surface states do not hybridize with the support, i.e. the semiconducting surfaces are insulating. Here I will focus on the latest results of macroscopic transport measurements on Pb quantum wires grown on vicinal Si(111) showing indeed a one-dimensional transport behavior. PMID:21817211

  8. Energy transfer in nanostructured materials

    NASA Astrophysics Data System (ADS)

    Haughn, Chelsea

    Energy transport and loss are critical to the performance of optoelectronic devices such as photovoltaics and terahertz imaging devices. Nanostructured materials provide many opportunities to tailor transport and loss parameters for specific device applications. However, it has been very difficult to correlate specific nanoscale structural parameters with changes in these performance metrics. I report the development of new ways of using time-resolved photoluminescence (TRPL) to probe charge and energy transport and loss dynamics. These techniques are applied to several types of nanostructured materials, including bulk semiconductors with defects, self-assembled quantum dots and colloidal quantum dots. First, GaAs/InP double heterostructures grown via metal organic chemical vapor deposition (MOCVD) were characterized with TRPL. TRPL is typically used to extract minority carrier lifetimes, but we discovered that the measured lifetime depended critically on the intensity of the exciting laser. We developed a Shockley-Read-Hall model to extract trap state densities from intensity-dependent TRPL measurements. Second, we characterized energy and charge transfer between InAs quantum dots and ErAs nanoinclusions within III-V heterostructures. Using intensity- and temperature-dependent TRPL, we confirmed tunneling as the dominant mechanism of charge transport and characterized the electronic structure of the ErAs nanoparticles. Finally, we characterized energy transport in colloidal quantum dot cascade structures. These cascade structures utilize Forster Resonance Energy Transfer and trap state recycling to funnel excitons from donor layers to acceptor layers and suggest a promising method for avoiding losses associated with surface trap states. Collectively, the analysis of these disparate material types advances our understanding of energy dynamics in nanostructured materials and improves our ability to design the next generation of photovoltaic and optoelectronic

  9. Nanostructures, systems, and methods for photocatalysis

    SciTech Connect

    Reece, Steven Y.; Jarvi, Thomas D.

    2015-12-08

    The present invention generally relates to nanostructures and compositions comprising nanostructures, methods of making and using the nanostructures, and related systems. In some embodiments, a nanostructure comprises a first region and a second region, wherein a first photocatalytic reaction (e.g., an oxidation reaction) can be carried out at the first region and a second photocatalytic reaction (e.g., a reduction reaction) can be carried out at the second region. In some cases, the first photocatalytic reaction is the formation of oxygen gas from water and the second photocatalytic reaction is the formation of hydrogen gas from water. In some embodiments, a nanostructure comprises at least one semiconductor material, and, in some cases, at least one catalytic material and/or at least one photosensitizing agent.

  10. Some nanostructural features in ceramics.

    PubMed

    Wen, S L

    1987-12-01

    Nanostructural features in some ceramics have been discussed and reviewed. Based on our research results and recent published investigations, many topics, such as grain, grain boundary, interface film, grain boundary engineering, microcrack, microdomain, nanodomain, domain boundary, and phase transformation, etc., have been dealt with; and many materials, such as Si3N4, beta''-Al2O3, MgO, SiC, (Hg, Cd) Te, BNN, ZrO2, PLZT, CdSe, Ca10(PO4)6, (OH)2, etc., have been involved. The results are important to understand the relation between the structure and property of materials and to improve the materials' technology. PMID:3505597

  11. Superradiance in spherical layered nanostructures

    NASA Astrophysics Data System (ADS)

    Goupalov, S. V.

    2016-06-01

    We propose a design of a spherically symmetric nanostructure consisting of alternate concentric semiconductor and dielectric layers. The exciton states in different semiconductor layers of such a structure interact via the common electromagnetic field of light. We show that, if the exciton states in N semiconductor layers are in resonance with one another, then a superradiant state emerges under optical excitation of such a structure. We discuss the conditions under which superradiance can be observed and show that they strongly depend on the valence-band structure of the semiconductor layers.

  12. Core-shell nanostructured catalysts.

    PubMed

    Zhang, Qiao; Lee, Ilkeun; Joo, Ji Bong; Zaera, Francisco; Yin, Yadong

    2013-08-20

    Novel nanotechnologies have allowed great improvements in the syn-thesis of catalysts with well-controlled size, shape, and surface properties. Transition metal nanostructures with specific sizes and shapes, for instance, have shown great promise as catalysts with high selectivities and relative ease of recycling. Researchers have already demonstrated new selective catalysis with solution-dispersed or supported-metal nanocatalysts, in some cases applied to new types of reactions. Several challenges remain, however, particularly in improving the structural stability of the catalytic active phase. Core-shell nanostructures are nanoparticles encapsulated and protected by an outer shell that isolates the nanoparticles and prevents their migration and coalescence during the catalytic reactions. The synthesis and characterization of effective core-shell catalysts has been at the center of our research efforts and is the focus of this Account. Efficient core-shell catalysts require porous shells that allow free access of chemical species from the outside to the surface of nanocatalysts. For this purpose, we have developed a surface-protected etching process to prepare mesoporous silica and titania shells with controllable porosity. In certain cases, we can tune catalytic reaction rates by adjusting the porosity of the outer shell. We also designed and successfully applied a silica-protected calcination method to prepare crystalline shells with high surface area, using anatase titania as a model system. We achieved a high degree of control over the crystallinity and porosity of the anatase shells, allowing for the systematic optimization of their photocatalytic activity. Core-shell nanostructures also provide a great opportunity for controlling the interaction among the different components in ways that might boost structural stability or catalytic activity. For example, we fabricated a SiO₂/Au/N-doped TiO₂ core-shell photocatalyst with a sandwich structure that showed

  13. SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials.

    PubMed

    Chan, An-Wen; Tetzlaff, Jennifer M; Gøtzsche, Peter C; Altman, Douglas G; Mann, Howard; Berlin, Jesse A; Dickersin, Kay; Hróbjartsson, Asbjørn; Schulz, Kenneth F; Parulekar, Wendy R; Krleza-Jeric, Karmela; Laupacis, Andreas; Moher, David

    2013-01-01

    High quality protocols facilitate proper conduct, reporting, and external review of clinical trials. However, the completeness of trial protocols is often inadequate. To help improve the content and quality of protocols, an international group of stakeholders developed the SPIRIT 2013 Statement (Standard Protocol Items: Recommendations for Interventional Trials). The SPIRIT Statement provides guidance in the form of a checklist of recommended items to include in a clinical trial protocol. This SPIRIT 2013 Explanation and Elaboration paper provides important information to promote full understanding of the checklist recommendations. For each checklist item, we provide a rationale and detailed description; a model example from an actual protocol; and relevant references supporting its importance. We strongly recommend that this explanatory paper be used in conjunction with the SPIRIT Statement. A website of resources is also available (www.spirit-statement.org). The SPIRIT 2013 Explanation and Elaboration paper, together with the Statement, should help with the drafting of trial protocols. Complete documentation of key trial elements can facilitate transparency and protocol review for the benefit of all stakeholders. PMID:23303884

  14. An ecogeomorphic model of tidal channel initiation and elaboration in progressive marsh accretional contexts

    NASA Astrophysics Data System (ADS)

    Belliard, J.-P.; Toffolon, M.; Carniello, L.; D'Alpaos, A.

    2015-06-01

    The formation and evolution of tidal networks have been described through various theories which mostly assume that tidal network development results from erosional processes, therefore emphasizing the chief role of external forcing triggering channel net erosion such as tidal currents. In contrast, in the present contribution we explore the influence of sediment supply in governing tidal channel initiation and further elaboration using an ecogeomorphic modeling framework. This deliberate choice of environmental conditions allows for the investigation of tidal network growth and development in different sedimentary contexts and provides evidences for the occurrence of both erosional and depositional channel-forming processes. Results show that these two mechanisms in reality coexist but act at different time scales: channel initiation stems from erosional processes, while channel elaboration mostly results from depositional processes. Furthermore, analyses suggest that tidal network ontogeny is accelerated as the marsh accretional activity increases, revealing the high magnitude and prevalence of the depositional processes in governing the morphodynamic evolution of the tidal network. On a second stage, we analyze the role of different initial topographic configurations in driving the development of tidal networks. Results point out an increase in network complexity over highly perturbed initial topographic surfaces, highlighting the legacy of initial conditions on channel morphological properties. Lastly, the consideration that landscape evolution depends significantly on the parameterization of the vegetation biomass distribution suggests that the claim to use uncalibrated models for vegetation dynamics is still questionable when studying real cases.

  15. Clarifying the best interests standard: the elaborative and enumerative strategies in public policy-making.

    PubMed

    Lim, Chong-Ming; Dunn, Michael C; Chin, Jacqueline J

    2016-08-01

    One recurring criticism of the best interests standard concerns its vagueness, and thus the inadequate guidance it offers to care providers. The lack of an agreed definition of 'best interests', together with the fact that several suggested considerations adopted in legislation or professional guidelines for doctors do not obviously apply across different groups of persons, result in decisions being made in murky waters. In response, bioethicists have attempted to specify the best interests standard, to reduce the indeterminacy surrounding medical decisions. In this paper, we discuss the bioethicists' response in relation to the state's possible role in clarifying the best interests standard. We identify and characterise two clarificatory strategies employed by bioethicists -elaborative and enumerative-and argue that the state should adopt the latter. Beyond the practical difficulties of the former strategy, a state adoption of it would inevitably be prejudicial in a pluralistic society. Given the gravity of best interests decisions, and the delicate task of respecting citizens with different understandings of best interests, only the enumerative strategy is viable. We argue that this does not commit the state to silence in providing guidance to and supporting healthcare providers, nor does it facilitate the abuse of the vulnerable. Finally, we address two methodological worries about adopting this approach at the state level. The adoption of the enumerative strategy is not defeatist in attitude, nor does it eventually collapse into (a form of) the elaborative strategy. PMID:27145811

  16. The ESCRT machinery influences haem uptake and capsule elaboration in Cryptococcus neoformans

    PubMed Central

    Hu, Guanggan; Caza, Mélissa; Cadieux, Brigitte; Bakkeren, Erik; Do, Eunsoo; Jung, Won Hee; Kronstad, James W.

    2015-01-01

    Summary Iron availability is a key determinant of virulence in the pathogenic fungus Cryptococcus neoformans. Previous work revealed that the ESCRT (endosomal sorting complex required for transport) protein Vps23 functions in iron acquisition, capsule formation and virulence. Here, we further characterized the ESCRT machinery to demonstrate that defects in the ESCRT-II and III complexes caused reduced capsule attachment, impaired growth on haem and resistance to non-iron metalloprotoporphyrins. The ESCRT mutants shared several phenotypes with a mutant lacking the pH-response regulator Rim101 and, in other fungi, the ESCRT machinery is known to activate Rim101 via proteolytic cleavage. We therefore expressed a truncated and activated version of Rim101 in the ESCRT mutants and found that this allele restored capsule formation but not growth on haem, thus suggesting a Rim101-independent contribution to haem uptake. We also demonstrated that the ESCRT machinery acts downstream of the cAMP/protein kinase A pathway to influence capsule elaboration. Defects in the ESCRT components also attenuated virulence in macrophage survival assays and a mouse model of cryptococcosis to a greater extent than reported for loss of Rim101. Overall, these results indicate that the ESCRT complexes function in capsule elaboration, haem uptake and virulence via Rim101-dependent and independent mechanisms. PMID:25732100

  17. Elaborations for the Validation of Causal Bridging Inferences in Text Comprehension.

    PubMed

    Morishima, Yasunori

    2016-08-01

    The validation model of causal bridging inferences proposed by Singer and colleagues (e.g., Singer in Can J Exp Psychol, 47(2):340-359, 1993) claims that before a causal bridging inference is accepted, it must be validated by existing knowledge. For example, to understand "Dorothy took the aspirins. Her pain went away," one first computes a mediating idea RELIEVE [ASPIRIN, PAIN]. Then, the truth of it is validated on the basis of existing knowledge. The present study examined the hypothesis that a causal inference would be drawn and validated even when validating knowledge is not familiar or available because elaborations are made to retrieve or construct such knowledge. Experiment 1 showed that people tend to judge naturalness of a text based on causal relations and that causality was indeed recognized in those texts in which the antecedent sentence and the consequence sentence are not linked by familiar knowledge. Experiment 2, which measured sentence reading times, showed that while sentence processing times were longer for such texts than texts involving familiar knowledge, there was no difference between these texts in reading the subsequent sentence describing the validating idea. These results provided evidence supporting elaboration as well as validation of causal bridging inferences. PMID:26210351

  18. SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials

    PubMed Central

    Tetzlaff, Jennifer M; Gøtzsche, Peter C; Altman, Douglas G; Mann, Howard; Berlin, Jesse A; Dickersin, Kay; Hróbjartsson, Asbjørn; Schulz, Kenneth F; Parulekar, Wendy R; Krleža-Jerić, Karmela; Laupacis, Andreas; Moher, David

    2013-01-01

    High quality protocols facilitate proper conduct, reporting, and external review of clinical trials. However, the completeness of trial protocols is often inadequate. To help improve the content and quality of protocols, an international group of stakeholders developed the SPIRIT 2013 Statement (Standard Protocol Items: Recommendations for Interventional Trials). The SPIRIT Statement provides guidance in the form of a checklist of recommended items to include in a clinical trial protocol. This SPIRIT 2013 Explanation and Elaboration paper provides important information to promote full understanding of the checklist recommendations. For each checklist item, we provide a rationale and detailed description; a model example from an actual protocol; and relevant references supporting its importance. We strongly recommend that this explanatory paper be used in conjunction with the SPIRIT Statement. A website of resources is also available (www.spirit-statement.org). The SPIRIT 2013 Explanation and Elaboration paper, together with the Statement, should help with the drafting of trial protocols. Complete documentation of key trial elements can facilitate transparency and protocol review for the benefit of all stakeholders. PMID:23303884

  19. Dispersion and separation of nanostructured carbon in organic solvents

    NASA Technical Reports Server (NTRS)

    Landi, Brian J. (Inventor); Raffaelle, Ryne P. (Inventor); Ruf, Herbert J. (Inventor); Evans, Christopher M. (Inventor)

    2011-01-01

    The present invention relates to dispersions of nanostructured carbon in organic solvents containing alkyl amide compounds and/or diamide compounds. The invention also relates to methods of dispersing nanostructured carbon in organic solvents and methods of mobilizing nanostructured carbon. Also disclosed are methods of determining the purity of nanostructured carbon.

  20. Biocompatibility of plasma nanostructured biopolymers

    NASA Astrophysics Data System (ADS)

    Slepičková Kasálková, N.; Slepička, P.; Bačáková, L.; Sajdl, P.; Švorčík, V.

    2013-07-01

    Many areas of medicine such as tissue engineering requires not only mastery of modification techniques but also thorough knowledge of the interaction of cells with solid state substrates. Plasma treatment can be used to effective modification, nanostructuring and therefore can significantly change properties of materials. In this work the biocompatibility of the plasma nanostructured biopolymers substrates was studied. Changes in surface chemical structure were studied by X-ray photoelectron spectroscopy (XPS). The morphology pristine and modified samples were determined using atomic force microscopy (AFM). The surface wettability was determined by goniometry from contact angle. Biocompatibility was determined by in vitro tests, the rat vascular smooth muscle cells (VSMCs) were cultivated on the pristine and plasma modified biopolymer substrates. Their adhesion, proliferation, spreading and homogeneous distribution on polymers was monitored. It was found that the plasma treatment leads to rapid decrease of contact angle for all samples. Contact angle decreased with increasing time of modification. XPS measurements showed that plasma treatment leads to changes in ratio of polar and non-polar groups. Plasma modification was accompanied by a change of surface morphology. Biological tests found that plasma treatment have positive effect on cells adhesion and proliferation cells and affects the size of cell's adhesion area. Changes in plasma power or in exposure time influences the number of adhered and proliferated cells and their distribution on biopolymer surface.

  1. Quantitative Characterization of Nanostructured Materials

    SciTech Connect

    Dr. Frank Bridges, University of California-Santa Cruz

    2010-08-05

    The two-and-a-half day symposium on the "Quantitative Characterization of Nanostructured Materials" will be the first comprehensive meeting on this topic held under the auspices of a major U.S. professional society. Spring MRS Meetings provide a natural venue for this symposium as they attract a broad audience of researchers that represents a cross-section of the state-of-the-art regarding synthesis, structure-property relations, and applications of nanostructured materials. Close interactions among the experts in local structure measurements and materials researchers will help both to identify measurement needs pertinent to real-world materials problems and to familiarize the materials research community with the state-of-the-art local structure measurement techniques. We have chosen invited speakers that reflect the multidisciplinary and international nature of this topic and the need to continually nurture productive interfaces among university, government and industrial laboratories. The intent of the symposium is to provide an interdisciplinary forum for discussion and exchange of ideas on the recent progress in quantitative characterization of structural order in nanomaterials using different experimental techniques and theory. The symposium is expected to facilitate discussions on optimal approaches for determining atomic structure at the nanoscale using combined inputs from multiple measurement techniques.

  2. Process Development for Nanostructured Photovoltaics

    SciTech Connect

    Elam, Jeffrey W.

    2015-01-01

    Photovoltaic manufacturing is an emerging industry that promises a carbon-free, nearly limitless source of energy for our nation. However, the high-temperature manufacturing processes used for conventional silicon-based photovoltaics are extremely energy-intensive and expensive. This high cost imposes a critical barrier to the widespread implementation of photovoltaic technology. Argonne National Laboratory and its partners recently invented new methods for manufacturing nanostructured photovoltaic devices that allow dramatic savings in materials, process energy, and cost. These methods are based on atomic layer deposition, a thin film synthesis technique that has been commercialized for the mass production of semiconductor microelectronics. The goal of this project was to develop these low-cost fabrication methods for the high efficiency production of nanostructured photovoltaics, and to demonstrate these methods in solar cell manufacturing. We achieved this goal in two ways: 1) we demonstrated the benefits of these coatings in the laboratory by scaling-up the fabrication of low-cost dye sensitized solar cells; 2) we used our coating technology to reduce the manufacturing cost of solar cells under development by our industrial partners.

  3. EDITORIAL: Nanostructures + Light = 'New Optics'

    NASA Astrophysics Data System (ADS)

    Zheludev, Nikolay; Shalaev, Vladimir

    2005-02-01

    Suddenly, at the end of the last century, classical optics and classical electrodynamics became fashionable again. Fields that several generations of researchers thought were comprehensively covered by the famous Born and Wolf textbook and were essentially dead as research subjects were generating new excitement. In accordance with Richard Feynman’s famous quotation on nano-science, the optical community suddenly discovered that 'there is plenty of room at the bottom'—mixing light with small, meso- and nano-structures could generate new physics and new mind-blowing applications. This renaissance began when the concept of band structure was imported from electronics into the domain of optics and led to the development of what is now a massive research field dedicated to two- and three-dimensional photonic bandgap structures. The field was soon awash with bright new ideas and discoveries that consolidated the birth of the 'new optics'. A revision of some of the basic equations of electrodynamics led to the suspicion that we had overlooked the possibility that the triad of wave vector, electric field and magnetic field, characterizing propagating waves, do not necessarily form a right-handed set. This brought up the astonishing possibilities of sub-wavelength microscopy and telescopy where resolution is not limited by diffraction. The notion of meta-materials, i.e. artificial materials with properties not available in nature, originated in the microwave community but has been widely adopted in the domain of optical research, thanks to rapidly improving nanofabrication capabilities and the development of sub-wavelength scanning imaging techniques. Photonic meta-materials are expected to open a gateway to unprecedented electromagnetic properties and functionality unattainable from naturally occurring materials. The structural units of meta-materials can be tailored in shape and size; their composition and morphology can be artificially tuned, and inclusions can be

  4. Silicon-embedded copper nanostructure network for high energy storage

    DOEpatents

    Yu, Tianyue

    2016-03-15

    Provided herein are nanostructure networks having high energy storage, electrochemically active electrode materials including nanostructure networks having high energy storage, as well as electrodes and batteries including the nanostructure networks having high energy storage. According to various implementations, the nanostructure networks have high energy density as well as long cycle life. In some implementations, the nanostructure networks include a conductive network embedded with electrochemically active material. In some implementations, silicon is used as the electrochemically active material. The conductive network may be a metal network such as a copper nanostructure network. Methods of manufacturing the nanostructure networks and electrodes are provided. In some implementations, metal nanostructures can be synthesized in a solution that contains silicon powder to make a composite network structure that contains both. The metal nanostructure growth can nucleate in solution and on silicon nanostructure surfaces.

  5. Energetics of hydrogen storage in organolithium nanostructures

    SciTech Connect

    Namilae, Sirish; Fuentes-Cabrera, Miguel A; Radhakrishnan, Balasubramaniam; Gorti, Sarma B; Nicholson, Don M

    2007-01-01

    Ab-initio calculations based on the second order Moller-Plesset perturbation theory (MP2) were used to investigate the interaction of molecular hydrogen with alkyl lithium organometallic compounds. It is found that lithium in organolithium structures attracts two hydrogen molecules with a binding energy of about 0.14 eV. The calculations also show that organolithium compounds bind strongly with graphitic nanostructures. Therefore, these carbon based nanostructures functionalized with organolithium compounds can be effectively used for storage of molecular hydrogen. Energetics and mechanisms for achieving high weight percent hydrogen storage in organolithium based nanostructures are discussed.

  6. Ceramic nanostructures and methods of fabrication

    DOEpatents

    Ripley, Edward B.; Seals, Roland D.; Morrell, Jonathan S.

    2009-11-24

    Structures and methods for the fabrication of ceramic nanostructures. Structures include metal particles, preferably comprising copper, disposed on a ceramic substrate. The structures are heated, preferably in the presence of microwaves, to a temperature that softens the metal particles and preferably forms a pool of molten ceramic under the softened metal particle. A nano-generator is created wherein ceramic material diffuses through the molten particle and forms ceramic nanostructures on a polar site of the metal particle. The nanostructures may comprise silica, alumina, titania, or compounds or mixtures thereof.

  7. Nanostructured lead sulfide: synthesis, structure and properties

    NASA Astrophysics Data System (ADS)

    Sadovnikov, S. I.; Gusev, A. I.; Rempel, A. A.

    2016-07-01

    The theoretical and experimental results of recent studies dealing with nanostructured lead sulfide are summarized and analyzed. The key methods for the synthesis of nanostructured lead sulfide are described. The crystal structure of PbS in nanopowders and nanofilms is discussed. The influence of the size of nanostructure elements on the optical and thermal properties of lead sulfide is considered. The dependence of the band gap of PbS on the nanoparticle (crystallite) size for powders and films is illustrated. The bibliography includes 222 references.

  8. Laser nanostructuring of polymers: Ripples and applications

    NASA Astrophysics Data System (ADS)

    Castillejo, Marta; Ezquerra, Tiberio A.; Martín, Margarita; Oujja, Mohamed; Pérez, Susana; Rebollar, Esther

    2012-07-01

    Polymer nanostructures and nanopatterns are being profusely used for developing next-generation organic devices with analytical and biological functions and photonic applications. Laser based strategies constitute an advantageous approach for the assembly and control of this type of soft matter nanostructures as they afford the sought versatility and reliability. Recent and on-going research on laser nanostructuring of thin films of synthetic polymers and natural biopolymers will be exemplified by studies on the generation of laser induced periodic surface structures (LIPSS) and their use for surface enhanced Raman spectroscopy (SERS) based sensors.

  9. Fabrication and characterization of amorphous silica nanostructures

    NASA Astrophysics Data System (ADS)

    Jin, Lei; Wang, Jianbo; Cao, Guangyi; Choy, Wallace C. H.

    2008-06-01

    Large-scale amorphous silica nanostructures, including nanowires, nanotubes and flowerlike nanowire bunches depending on the position, have been fabricated on silicon wafer through a cheap route under the assistance of gold and germanium. Accompanying the observation of blue-green light emission, comprehensive micro-structural characterization reveals that the growth of nanostructures is catalyzed only by gold whereas the final morphology of nanostructures depends on the location to germanium ball. Au 2Si, a compound of gold and silicon, is also disclosed as an intermediate state during the catalysis. Correspondingly, a growth scheme is proposed based on the experimental results and the vapor-liquid-solid mechanism.

  10. Emergence of ferroelectricity in antiferroelectric nanostructures.

    PubMed

    Mani, B K; Herchig, R; Glazkova, E; Lisenkov, S; Ponomareva, I

    2016-05-13

    First-principles-based finite-temperature simulations are used to predict the emergence of ferroelectricity in antiferroelectric nanostructures made of PbZrO3. The phenomenon is expected to occur in antiferroelectric nanodots, nanowires, and thin films with good surface charge compensation and can be explained by the recently proposed surface effect [1]. Our computations provide a microscopic insight into the equilibrium phases, phase competition, and electrical properties of PbZrO3 nanostructures. The dependence of these properties on the electrical boundary conditions and nanostructure size is investigated. PMID:27039877