1,720,960 research outputs found
Zeolites for sustainable agricolture: furfural encapsulation and controlled release in ZSM-5
No full textWidespread application of synthetic nematicide on the crops aimed to fight nematode parasite could be a threat to human health and overall environmental quality. Most of synthetic nematicides have been withdrawn from the market, due to their toxicity. This had led to looking for a non-chemical alternative which must be equally effective and eco-friendly, derived from natural materials, aiming to reduce synthetic pesticide input. Recently, it has been proved that an aldehyde, namely furfural, is effective against Meloidogyne sp. (a dangerous specie of nematode) [1]. This latter biomolecule can be easily extracted from Melia azedarach fruits, a tree growing in tropical and subtropical areas.
This work is part of a wider multidisciplinary project, which aims to develop an innovative, easy to produce, and eco-sustainable nematicidal formulate by combining a botanical extract of known nematicidal activity with environmentally friendly porous materials. Specifically, an aldehyde - namely, furfural and salicylaldehyde, which is known for its occurrence in Melia azedarach (MA) tree and mainly responsible for the plant defense ability against nematodes - wase encapsulated into microporous alumina-silicate matrices (zeolites) to obtain a nematicidal formulate with a controlled release of the bioactive aldehyde. From a structural point of view, the project is focused on the study of interactions that take place between the guest nematicidal molecule and the host zeolite carrier in order to elucidate, at an atomistic level, the mechanisms that control the adsorption (encapsulation) and desorption (controlled release) properties. The first part of the project was addressed to define the zeolite with the highest encapsulation capacity and that was capable to prolong the bioactivity of the embedded products (encapsulated aldehyde). With this purpose, several zeolites (zeolite Y, mordenite, ferrierite, beta and ZSM-5) with different silica/alumina ratio (from 10 up to 500), pore architecture and type/position of adsorbing sites were tested. In this study the furfural encapsulation into microporous alumina-silicate ZSM-5 (SiO2/Al2O3 = 500) zeolite will be discussed. Furfural was encapsulated into zeolite via adsorption from water and adsorption equilibrium was monitored by adsorption kinetics. Adsorption isotherms were determined in order to define the affinity and maximal adsorption capacity and selectivity of tested zeolite for the selected nematicide. The monitoring was done by liquid chromatographic analysis (HPLC) of equilibrium solutions performed via Jasco 880-PU Intelligent and thermogravimetric analysis (25°-900°C, heating rate 10°C/min) of loaded zeolite samples. Electronic nose data were collected on AIRSENSE PEN3. After adsorption, the zeolite samples were structurally characterized with X-ray diffraction (XRD) technique (Bruker D8 Advance diffractometer equipped with SOL-X detector) - coupled with Rietveld refinements of the diffraction patterns. Structural analysis was used to prove the embedding of the aldehydes inside the zeolite pores and to define the interaction distance between the porous framework and each molecule. This combined diffractometric, chromatographic and thermogravimetric study allowed us to: 1) evaluate the maximum adsorption capacity of hydrophobic zeolite against furfural molecules ; 2) localise the biomolecules in the zeolite channel system; 3) probe the interaction between the adsorbate and the zeolite framework; 4) evaluate the release kinetics of the encapsulated molecules in gas phase.
Our results highlighted that ZSM-5 can be useful tool for nematode pest management, and may help improving environmental protection while minimizing risk to overall health.
[1] Ntalli, N. G., Cottiglia, F, Bueno, C. A., Alché, L. E., Leonti, M, Vargiu, S., Bifulco, E., Menkissoglu-Spiroudi, U., Caboni, P. (2010): Cytotoxic tirucullane triterpenoids from Melia azedarach fruits. Molecules, Ann. Appl. Biol. 15, 5866-5877
MechaTag: A Mechanical Fiducial Marker and the Detection Algorithm
Full text linkFiducial markers are fundamental components of many computer vision systems that help, through their unique features (e.g., shape, color), a fast localization of spatial objects in unstructured scenarios. They find applications in many scientific and industrial fields, such as augmented reality, human-robot interaction, and robot navigation. In order to overcome the limitations of traditional paper-printed fiducial markers (i.e. deformability of the paper surface, incompatibility with industrial and harsh environments, complexity of the shape to reproduce directly on the piece), we aim at exploiting existing, or additionally fabricated, structural features on rigid bodies (e.g., holes), developing a fiducial mechanical marker system called MechaTag. Our system, endowed with a dedicated algorithm, is able to minimize recognition errors and to improve repeatability also in case of ill boundary conditions (e.g., partial illumination). We assess MechaTag in a pilot study, achieving a robustness of fiducial marker recognition above 95% in different environment conditions and position configurations. The pilot study was conducted by guiding a robotic platform in different poses in order to experiment with a wide range of working conditions. Our results make MechaTag a reliable fiducial marker system for a wide range of robotic applications in harsh industrial environments without losing accuracy of recognition due to the shape and material
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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