1,720,955 research outputs found
Synthesis and characterization of new organic materials with potential application in water treatment
Full text linkThe PhD project deals with synthesis and characterization of organic photosensitizers in particular porphyrins and expanded porhyrins (pentaphyrins) for potential application in water disinfection. The growing population of harmful microbes and the development of resistance towards disinfectants/drugs calls for alternative and efficient methods of microbe destruction. Photodynamic therapy or photoinactivation is one such method that uses individually harmless components to destroy microorganisms. In view of this, we have carried out series of trial synthesis for new photsensitizers in particular expanded porphyrins. The aim is to obtain photosensitizers that can deliver broad spectrum of action against both Gram positive and Gram negative bacteria and also other pathogenic organisms. On the other hand, the immobilization of porphyrins onto solid supports like magnetic nanoparticles and polymers were also studied so that the recovery and reuse of photosensitizers is possible. The polymer supported photosensitizers have remarkable photodynamic activity against Gram positive bacteria in presence of visible light and looks promising for further study as well as application in treating water bodies to make them microbe free
Phototreatment of Water by Organic Photosensitizers and Comparison with Inorganic Semiconductors
Full text linkPhototreatment of water is drawing the attention of many as a promising alternative to replace methods like chlorination, ozonization, and other oxidation processes, used in current disinfection methods limiting harmful side-products and by-products that can cause damage to the fauna and flora. Porphyrins, phthalocyanines, and other related organic dyes are well known for their use in photodynamic therapy (PDT). These photosensitizers cause cell death by generating reactive oxygen species (ROS) especially singlet oxygen in the presence of light. Such molecules are also being explored for photodynamically treating microbial infections, killing of unwanted pathogens in the environment, and oxidation of chemical pollutants. The process of photosensitisation (phototreatment) can be applied for obtaining clean, microbe-free water, thus exploiting the versatile properties of photosensitizers. This review collects the various attempts carried out for phototreatment of water using organic photosensitizers. For comparison, some reports of semiconductors (especially TiO2) used in photocatalytic treatment of water are also mentioned
“Clicking” Porphyrins to Magnetic Nanoparticles for Photodynamic Therapy
No full textA method for the preparation of superparamagnetic iron oxide nanoparticle–porphyrin (SPION-TPP) conjugates through click chemistry, which can be used as novel theranostic nanoagents for photodynamic therapy is developed. The synthesis, characterisation, and evaluation of the photocytotoxicity profiles of the nanoconjugates prepared is reported. Upon light irradiation, SPION-TPP nanoconstructs promote a photodynamic effect in vitro in murine amelanotic melanoma B78-H1 cells, with IC50 values in the region of 800 nM, similarly to unbound TPP, whereas they remain non-cytotoxic in the dark. However, these nanoconstructs show poor cellular uptake, which influences a linear dose–response effect. Therefore, the improvement of delivery to cells has also been studied by conjugating a well-known cell-penetrating peptide (TAT peptide) to the SPION-TPP nanoparticles. The new nanoconstructs show lower IC50 values (in the region of 500 nM) and a clear dose–response effect. Our results suggest that TAT-conjugated SPION-TPP nanoparticles are efficient nanodevices both for tracking drugs by means of magnetic resonance imaging (MRI)-based techniques and for treating cancer cells through photodynamic therapy, thus functioning as promising theranostic nanoagents
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
- …
