1,721,013 research outputs found
Multifunctional polymer-based nanocomposites for synergistic adsorption and photocatalytic degradation of mixed pollutants in water
No full textWater pollution is a growing concern for mankind due to its harmful effects on humans, animals and plants. Usually, several pollutants are present in wastewater. For example, dyes and antibiotics are found in wastewater because of their widespread use in factories and hospitals. However, one single technique, e.g. either adsorption or photocatalysis, cannot easily remove more than one kind of pollutant, especially by using one single material in water. For this reason, here multifunctional iron(ii,iii) oxide/poly(N-isopropylacrylamide-co-methacrylic acid)/silver-titanium dioxide (Fe3O4/P(NIPAM-co-MAA)/Ag-TiO2) nanocomposites were used to remove a mixture of pollutants from water. Specifically, three types of experiments were performed to evaluate the adsorption capacity and photodegradation activity of the nanocomposites towards the dye basic fuchsin (BF) and the antibiotic ciprofloxacin (CIP), which were added sequentially to the nanocomposites dispersion or were concurrently present as a mixture. The results demonstrated that the nanocomposites could adsorb BF, and subsequently photodegrade CIP under visible-light irradiation, if BF was the first added pollutant. As well, the nanocomposites could first degrade CIP under visible-light irradiation, and then adsorb BF if they were initially put in contact with CIP. Finally, the ability of adsorbing BF and photodegrading CIP was confirmed in the co-presence of the two pollutants.Independently of the order of addition, the nanocomposite could adsorb basic fuchsin (BF) and photodegrade ciprofloxacin (CIP) under visible-light irradiation. The multifunctional properties were proved as well in the co-presence of BF and CIP
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
A quest for supramolecular gelators: Silver(I) complexes with quinoline-urea derivatives
No full textThe quinoline urea derivatives 1,3-di(quinolin-5-yl)urea (DQ5U), 1-phenyl-3-(quinolin-6-yl)urea (PQ6U), 1-(isoquinolin-5-yl)-3-phenylurea (PiQ5U) and 1-phenyl-3-(3,5-bis(pyrid-2-yl)-1,2,4-triazol-4-yl)urea (PPT4U) have been synthesised and structurally characterized by powder and single crystal X-ray diffraction. Their gelator behaviour in the formation of Ag-complexes has been explored. Compound DQ5U proved capable of gelating the mixed solvent EtOH-DMF 1:2 (v/v) when mixed with 1 equivalent of AgNO3. In the case of PQ6U, two polymorphic forms of the complex [Ag(PQ6U)2]NO3, plus the solvated form [Ag(PQ6U)2]NO3·CH3CN, were crystallized. Photophysical characterization of the ligands has been conducted in solution, while fluorescence microscopy has been used to examine the microstructure and photophysical properties of the gels formed by PQ5U and DQ5U with AgNO3. © 2013 The Royal Society of Chemistry
The roadmap of colorectal cancer screening
Full text linkColorectal cancer (CRC) is the third most common form of cancer in terms of incidence and the second in terms of mortality worldwide. CRC develops over several years, thus highlighting the importance of early diagnosis. National screening programs based on fecal occult blood tests and subsequent colonoscopy have reduced the incidence and mortality, however improvements are needed since the participation rate remains low and the tests present a high number of false positive results. This review provides an overview of the CRC screening globally and the state of the art in approaches aimed at improving accuracy and participation in CRC screening, also considering the need for gender and age differentiation. New fecal tests and biomarkers such as DNA methylation, mutation or integrity, proteins and microRNAs are explored, including recent investigations into fecal microbiota. Liquid biopsy approaches, involving novel biomarkers and panels, such as circulating mRNA, micro‐ and long‐non‐coding RNA, DNA, proteins and extracellular vesicles are discussed. The approaches reported are based on quantitative PCR methods that could be easily applied to routine screening, or arrays and sequencing assays that should be better exploited to describe and identify candidate biomarkers in blood samples
Enhanced visible-light photodegradation of fluoroquinolone-based antibiotics andE. coligrowth inhibition using Ag-TiO2nanoparticles
No full textAntibiotics in wastewater represent a growing and worrying menace for environmental and human health fostering the spread of antimicrobial resistance. Titanium dioxide (TiO2) is a well-studied and well-performing photocatalyst for wastewater treatment. However, it presents drawbacks linked with the high energy needed for its activation and the fast electron-hole pair recombination. In this work, TiO2nanoparticles were decorated with Ag nanoparticles by a facile photochemical reduction method to obtain an increased photocatalytic response under visible light. Although similar materials have been reported, we advanced this field by performing a study of the photocatalytic mechanism for Ag-TiO2nanoparticles (Ag-TiO2NPs) under visible light taking in consideration also the rutile phase of the TiO2nanoparticles. Moreover, we examined the Ag-TiO2NPs photocatalytic performance against two antibiotics from the same family. The obtained Ag-TiO2NPs were fully characterised. The results showed that Ag NPs (average size: 23.9 ± 18.3 nm) were homogeneously dispersed on the TiO2surface and the photo-response of the Ag-TiO2NPs was greatly enhanced in the visible light region when compared to TiO2P25. Hence, the obtained Ag-TiO2NPs showed excellent photocatalytic degradation efficiency towards the two fluoroquinolone-based antibiotics ciprofloxacin (92%) and norfloxacin (94%) after 240 min of visible light irradiation, demonstrating a possible application of these particles in wastewater treatment. In addition, it was also proved that, after five Ag-TiO2NPs re-utilisations in consecutive ciprofloxacin photodegradation reactions, only a photocatalytic efficiency drop of 8% was observed. Scavengers experiments demonstrated that the photocatalytic mechanism of ciprofloxacin degradation in the presence of Ag-TiO2NPs is mainly driven by holes and ̇OH radicals, and that the rutile phase in the system plays a crucial role. Finally, Ag-TiO2NPs showed also antibacterial activity towardsEscherichia coli(E. coli) opening the avenue for a possible use of this material in hospital wastewater treatment
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
Country Report on Employability and Mobility of Bachelor Graduates in Italy: Mixed Outcomes of the Bologna Process
No full textIn order to make more reasonable international comparisons between graguate outcome studies, two main stylized facts of the Italian setting are spelled out: the rapid ageing of the population and the scarcity of youths; the scarcity of highly qualified manpower. Secondly, a very compact comparison is carried out on the characteristics of pre- and post-reform graduates and on the strengths and weaknesses of the Italian higher education system. This paper, after a short introduction, in paragraph 1. synthetically describes the study structure of the Italian higher education system and the main features of the Bologna Process reform in Italy. In paragraph 2 a short description is presented of the AlmaLaurea graduate surveys used for the analysis and the AlmaLaurea broad model. Paragraph 3 offers an account of the main characteristics of bachelor-level graduates, especially in terms of socio-biographic background and course of study. Some evidence on graduates’ international mobility is put forward in paragraph 4. In paragraph 5 the main features of the available evidence on employment and further studies of bachelors are presented, while paragraph 6 is devoted to the presentation of the main evidence concerning the professional success of bachelors. Paragraph 7 outlines the major conclusions that can be drawn, at this stage, on the open debate on the impact of the reform. The appendix displays basic data analysed in the previous paragraphs
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