1,720,984 research outputs found
A STUDY OF HYDROLYSIS ADSORPTION AND DEGRADATION OF PESTICIDES METHYL-PARATHION, LINDANE AND ATRAZINE ON NATURAL SUBSTRATES
No full textIN THIS WORK WE ATTEMPTED A STUDY OF THE MOST IMPORTANT FACTORS WHICH INFLUENCETHE FATE OF PESTICIDES METHYL-PARATHION, LINDANE AND ATRAZINE IN AQUATIC AND SOIL SYSTEMS. WE STUDIED THE KINETICS OF HYDROLYSIS OF THESE PESTICIDES IN RELATION WITH TEMPERATURE AND PH AND THE EXTENT OF ADSORPTION AND CATALYTIC DEGRADATION IN AQUATIC EMULSIONS OF SOILS FROM THESSALONIKI AND IOANNINA AREAS AS WELLAS OF MINERALS PHOSPHATE ORE, KAOLLINITE, FLY ASH, RED MUD AND Γ-ALUMINA. THE ABILITY OF THESE SOLID SUBSTRATES FOR ADSORPTION AND DEGRADATION WAS PROVED THAT IT DEPENDS ON THEIR CHEMICAL FORMATION AND THEIR BASIC PHYSICOCHEMICAL CHARACTERISTICS (PH, SPECIFIC SURFACE AREA, NUMBER OF ACID SITES AND THE ZERO POINT CHARGE). IN CONDITIONS AND IN EXPERIMENTS OF INVERSE GAS CHROMATOGRAPHY IT WAS SHOWED THAT THE THERMODYNAMIC PARAMETERS OF ADSORPTION OF PESTICIDES (-ΔΗ) AND (-ΔS) APPEAR A LINEAR DEPENDENCE WITH THE ZERO POINT CHARGE OF SOLID SUBSTRATES.THE SOIL PROPERTIES AS FAR AS THE MOST RAPID DETOXICATION OF PESTICIDE RESIDUES WAS IMPROVED WITH ADDITION OF SMALL AMOUNTS OF FLY ASH, WHICH HAS AN INCREASED ABILITY TO DEGRADATE THEIR MOLECULES. AT THE END THE PERSISTENT OF THESE THREE PESTICIDES WAS STUDIED IN NATURAL CONDITIONS ON FOUR CHARACTERISTICAL SOILS OF IOANNINA BASIN AND IT WAS SHOWED THAT THE PESTICIDE MOVEMENT ONTO THE SOIL ISCONTROLLED BY THE PHYSICAL TRANSPORTATION WITH THE RAINFALL WATERS.ΣΤΗΝ ΕΡΓΑΣΙΑ ΑΥΤΗ ΕΓΙΝΕ ΜΙΑ ΣΕΙΡΑ ΜΕΛΕΤΩΝ ΠΑΝΩ ΣΤΟΥΣ ΠΙΟ ΣΗΜΑΝΤΙΚΟΥΣ ΠΑΡΑΓΟΝΤΕΣΠΟΥ ΚΑΘΟΡΙΖΟΥΝ ΤΗΝ ΤΥΧΗ ΤΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ METHYL-PARATHION, LINDANE ΚΑΙ ATRAZINE ΣΕ ΥΔΑΤΙΚΑ ΚΑΙ ΕΔΑΦΙΚΑ ΣΥΣΤΗΜΑΤΑ. ΜΕΛΕΤΗΘΗΚΕ Η ΚΙΝΗΤΙΚΗ ΤΗΣ ΥΔΡΟΛΥΣΗΣ ΤΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ ΑΥΤΩΝ ΣΕ ΣΧΕΣΗ ΜΕ ΤΗΝ ΘΕΡΜΟΚΡΑΣΙΑ ΚΑΙ ΤΟ ΡΗ ΚΑΘΩΣ ΚΑΙ Η ΕΚΤΑΣΗ ΤΩΝ ΦΑΙΝΟΜΕΝΩΝ ΤΗΣ ΠΡΟΣΡΟΦΗΣΗΣ ΚΑΙ ΚΑΤΑΛΥΤΙΚΗΣ ΔΙΑΣΠΑΣΗΣ ΤΟΥΣ ΣΕ ΥΔΑΤΙΚΑ ΑΙΩΡΗΜΑΤΑ ΕΔΑΦΩΝ ΤΗΣ ΠΕΡΙΟΧΗΣ ΘΕΣΣΑΛΟΝΙΚΗΣ ΚΑΙ ΙΩΑΝΝΙΝΩΝ, ΟΡΥΚΤΩΝ ΤΟΥ ΦΩΣΦΟΡΙΤΗ ΚΑΙ ΤΟΥ ΚΑΟΛΙΝΗ, ΤΩΝ ΒΙΟΜΗΧΑΝΙΚΩΝ ΥΠΟΠΡΟΙΟΝΤΩΝ, ΙΠΤΑΜΕΝΗ ΤΕΦΡΑ ΚΑΙ ΚΟΚΚΙΝΗ ΛΑΣΠΗ ΚΑΙ ΤΗΣ Γ- ΑΛΟΥΜΙΝΑΣ. ΑΠΟΔΕΙΧΘΗΚΕ ΟΤΙ Η ΙΚΑΝΟΤΗΤΑ ΑΥΤΩΝ ΤΩΝ ΣΤΕΡΕΩΝ ΥΠΟΣΤΡΩΜΑΤΩΝ ΣΤΗΝ ΠΡΟΣΡΟΦΗΣΗ ΚΑΙ ΔΙΑΣΠΑΣΗ ΤΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ ΕΞΑΡΤΑΤΑΙ ΑΠΟ ΤΗΝ ΧΗΜΙΚΗ ΤΟΥΣ ΣΥΣΤΑΣΗ ΚΑΙ ΤΑ ΒΑΣΙΚΑ ΦΥΣΙΚΟΧΗΜΙΚΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΤΟΥΣ (ΡΗ, ΕΙΔΙΚΗ ΕΠΙΦΑΝΕΙΑ, ΑΡΙΘΜΟΣ ΟΞΙΝΩΝ ΕΠΙΦΑΝΕΙΑΚΩΝ ΘΕΣΕΩΝ ΚΑΙ ΣΗΜΕΙΟ ΜΗΔΕΝΙΚΟΥ ΦΟΡΤΙΟΥ). ΣΕ ΑΝΥΔΡΕΣ ΣΥΝΘΗΚΕΣ ΚΑΙ ΣΕ ΠΕΙΡΑΜΑΤΑ ΠΡΟΣΡΟΦΗΣΗΣ ΜΕ ΑΝΑΣΤΡΟΦΗ ΧΡΩΜΑΤΟΓΡΑΦΙΑ ΔΕΙΧΘΗΚΕ ΟΤΙ ΟΙ ΘΕΡΜΟΔΥΝΑΜΙΚΕΣ ΠΑΡΑΜΕΤΡΟΙ ΠΡΟΣΡΟΦΗΣΗΣ ΤΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ (-ΔΗ) ΚΑΙ (-ΔΣ) ΠΑΡΟΥΣΙΑΖΟΥΝ ΓΡΑΜΜΙΚΗ ΕΞΑΡΤΗΣΗ ΑΠΟ ΤΟ ΣΗΜΕΙΟ ΜΗΔΕΝΙΚΟΥ ΦΟΡΤΙΟΥ ΤΩΝ ΣΤΕΡΕΩΝ ΥΠΟΣΤΡΩΜΑΤΩΝ. ΟΙ ΙΔΙΟΤΗΤΕΣ ΤΩΝ ΕΔΑΦΩΝ ΟΣΟΝ ΑΦΟΡΑ ΤΗΝ ΠΙΟ ΓΡΗΓΟΡΗ ΕΞΑΛΕΙΨΗ ΤΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ ΒΕΛΤΙΩΘΗΚΑΝΜΕ ΤΗΝ ΠΡΟΣΘΗΚΗ ΜΙΚΡΩΝ ΠΟΣΟΤΗΤΩΝ ΙΠΤΑΜΕΝΗΣ ΤΕΦΡΑΣ (ΕΠΙΠΕΔΑ ΛΙΠΑΝΣΗΣ) ΠΟΥ ΕΧΕΙ ΜΙΑ ΑΥΞΗΜΕΝΗ ΙΚΑΝΟΤΗΤΑ ΣΤΟ ΝΑ ΔΙΑΣΠΑ ΤΑ ΜΟΡΙΑ ΤΟΥΣ. ΤΕΛΟΣ ΜΕΛΕΤΗΘΗΚΕ Η ΑΝΤΟΧΗ ΤΩΝ ΤΡΙΩΝ ΦΥΤΟΦΑΡΜΑΚΩΝ ΣΕ ΦΥΣΙΚΕΣ ΣΥΝΘΗΚΕΣ ΣΕ ΤΕΣΣΕΡΑ ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ ΕΔΑΦΗ ΤΟΥ ΛΕΚΑΝΟΠΕΔΙΟΥ ΙΩΑΝΝΙΝΩΝ ΚΑΙ ΔΕΙΧΘΗΚΕ ΟΤΙ Η ΚΙΝΗΣΗ ΤΟΥΣ ΜΕΣΑ ΣΤΗΝ ΜΑΖΑ ΤΟΥ ΕΔΑΦΟΥΣΚΑΘΟΡΙΖΕΤΑΙ ΑΠΟ ΤΟΝ ΦΥΣΙΚΟ ΠΑΡΑΓΟΝΤΑ ΤΗΣ ΜΕΤΑΦΟΡΑΣ ΜΕ ΤΑ ΝΕΡΑ ΤΩΝ ΒΡΟΧΟΠΤΩΣΕΩΝ
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
Enzyme-catalyzed cascade reactions with (nano)-biocatalytic systems
No full textThe present PhD thesis focuses on the design, development, and application of innovative multienzymatic biocatalytic systems in cascade reactions of biotechnological interest. These systems consist of more than one enzyme originating either from different organisms or from different classes of enzymes (e.g. hydrolases, oxodoreductases, etc.) and can be either free or co-immobilized on nanocarriers bearing characteristics of particular interest. This thesis examines the different approaches for the design and development of multienzymatic systems and investigates their potential in different biocatalytic applications. Specifically, the thesis presents the scientific studies obtained and are related to the development and optimization of multienzymatic systems for the hydrolysis of cellulose, the bioconversion of oleuropein to hydroxytyrosol and the enzymatic modification of various polymers. The characterization of the above systems in terms of their structure, activity and functional stability was based on a combined approach of various techniques, such as Ultraviolet-visible spectroscopy, Fluorescence Spectroscopy and Circular Dichroism among others. Overall, this thesis offers new insights and innovative approaches for the design of multienzymatic (nano)assemblies to improve the performance of various biocatalytic processes and to develop innovative biomaterials with improved properties. In the context of this PhD thesis, various methods for the design of multienzymatic systems were approached, such as the combined use of inorganic and organic support materials, the combined use of enzymes deriving from different classes, as well as the combined use of different reaction conditions to achieve the highest yields.
The first research topic of this thesis focuses on the preparation, characterization and application of a novel four-enzyme magnetic nanobiocatalyst developed through the simultaneous covalent co-immobilization of cellulase (CelDZ1), β-glucosidase (bgl), glucose oxidase (GOx) and horseradish peroxidase (HRP) on the surface of magnetic nanoparticles (MNPs) modified with (3-aminopropyl)triethoxysilane (APTES). The prepared nanobiocatalyst was characterized by various spectroscopic techniques. The co-immobilization procedure yielded the maximum immobilization efficiency (CelDZ1: 42%, bgl: 66%, GOx: 94% and HRP: 78%) at a concentration of glutaraldehyde (chemical reagent that acts as linker between enzyme and material) 10% v/v, after 2 h incubation and at a 1:1 ratio of total enzyme mass to nanomaterial. Co-immobilization led to an increase in the apparent affinity constant Km and a concomitant decrease in the maximum velocity Vmax of the co-immobilized enzymes. Studies on the thermal stability of the co-immobilized enzymes revealed an up to a 2-fold increase in the half-life constant and up to a 1.5-fold increase in the deactivation energy compared to the free enzymes. The enhancement of the thermodynamic parameters of the four enzymes co-immobilized on MNPs also indicates an increase in their thermal stability. Furthermore, the co-immobilized enzymes retained a significant percentage of their catalytic activity (up to 50%) after 5 reaction cycles at 50 °C and even after 24 days of incubation at 5 °C. Finally, the nanobiocatalyst was successfully applied to a four-step cascade reaction involving the hydrolysis of cellulose.
An innovative multi-enzyme nanobiocatalytic system was then developed consisting of the enzymes lipase A from Candida antarctica (CalA) and β-glucosidase from Thermotoga maritima (bgl) which were covalently co-immobilized on the surface of magnetic nanoparticles coated with chitosan (CS-MNPs). Several parameters affecting the co-immobilization process (glutaraldehyde concentration, incubation time, CS-MNPs to enzyme mass ratio and bgl to CalA mass ratio) were evaluated and optimized. The developed nanobiocatalyst was characterized by various spectroscopic techniques. Biochemical parameters such as the apparent kinetic constants and the thermal stability of both free and co-immobilized enzymes were also evaluated. The co-immobilized enzymes exhibited an increase in the apparent kinetic constant Km followed by a decrease in the Vmax value compared to the free enzymes, while a significant increase (>5-fold) in the thermal stability of immobilized CalA, both in individually immobilized and co-immobilized form, was observed after 24 h incubation at 60 °C. Finally, the nanobiocatalyst was effectively applied in the bioconversion of oleuropein to hydroxytyrosol, one of the most potent naturally occurring antioxidants, and could be recycled for up to 10 reaction cycles (240 hours of steady operation) at 60 °C, retaining more than 50% of of its initial activity.
In the third study of this thesis a series of polymers, including chitosan (CS), carboxymethylcellulose (CMC) and a chitosan-gelatin hybrid polymer (CS-GEL), were functionalized with ferulic acid (FA) obtained from the enzymatic treatment of arabinoxylan through the synergistic action of two enzymes, xylanase and feruloyl esterase. Subsequently, ferulic acid served as substrate for laccase from Agaricus bisporus (AbL) in order to enzymatically modify the aforementioned polymers. The successful incorporation of the ferulic acid oxidation products onto the various polymers was confirmed through various techniques such as ultraviolet-visible (UV-Vis) spectroscopy and attenuated total reflection (ATR) spectroscopy. In addition, enhancement of the antioxidant properties of the modified polymers was observed with two protocols. Finally, the modified polymers exhibited strong antimicrobial activity against bacterial populations of Escherichia coli strain BL21DE3, suggesting their potential application in the pharmaceutical, cosmetology and food industries.
The results of this thesis constitute an important contribution to the research field of biocatalysis, as they demonstrate the importance of developing innovative multi-enzymatic biocatalytic systems for a multitude of applications. The utilization of agro-industrial by-products and the production of biofuels are just some of the applications that can be achieved using such systems. The results of this thesis also demonstrate the possibility of developing innovative biological systems in vitro with improved characteristics, a necessary condition for the competitiveness of industry in the modern world. Finally, this work highlights the importance of nanotechnology in biocatalytic research, paving the way for further future research in this specific research field.375 σ
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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