1,720,965 research outputs found
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
Transgenes monitoring in an industrial soybean processing chain by DNA-based conventional approaches and biosensors
No full textThe development of analytical methods for genetically modified organisms (GMO) screening is of great interest. In particular, since even highly processed GMO-derived food products are covered by new European legislations, a great effort has been devoted to the application of the analytical tests to these products. This work describes a polymerase chain reaction-based qualitative screening assay and a biosensor based approach to detect transgenes in a Roundup Ready_ soybean processing line. Roundup Ready_ soybean was specifically analyzed in eight types of processed materials – seeds, crushed seeds, expander, crude flour, proteic flour, crude oil, degummed oil and lecithin – all derived from the same initial source and produced during the manufacturing process. Specific combinations of primers were used to differentiate sequences from the whole insert. The amplification of ‘‘marker” fragments with a maximum length of 500 bp was successfully achieved both in raw material (seeds) and in partially (crushed seeds, crude and proteic flours) and highly (crude and degummed oils and fluid lecithin) processed materials. Moreover, the extraction procedure was optimised and the polymerase chain reaction-electrophoresis analysis has been implemented by a biosensor-based approac
Affinity sensing for transgenes detection in anti-doping control
No full textSports authorities fear that a new form of doping called gene doping, based on the misuse of gene therapy, represents an emerging important problem and so far no methods are available for detecting it. The World Anti- Doping Agency (WADA) has included since 2003 for the first time gene doping methods in the “Prohibited List of Substances and Methods”, thus detection of this new form of doping is challenging for analytical chemists. In this work, we apply affinity-based biosensors (ABBs), in particular DNA piezoelectric sensing, for detection of target DNA sequences selected as transgenosis markers. In this work, two sequences widely used in transgenosis experiments have been identified as markers: the enhanced green fluorescence protein (EGFP) gene and the promoter of Cytomegalovirus (CMV). The biosensors are characterized in their analytical performances using synthetic oligonucleotides and amplified DNA obtained from purified plasmid used as a template. Finally they have been applied to transgenic human cell cultures (human embryonic kidney HEK-EGFP), transformed with the same plasmid and carrying the target markers. This represents the closest human real matrix available for our transgenes
Direct immobilisation of DNA probes for the development of affinity biosensors
No full textimmobilization chemistry for SPR sensin
DEVELOPMENT OF A NEW ANALYTICAL TOOL FOR TRACEABILITY OF TRANSGENES IN GENETICALLY MODIFIED PLANTS
No full textAnalytical techniques to track transgenes in GMO are essential both for the production and trade of modified crops in the view of the adoption of different new regulations by Government Institutions. A great effort has been devoted to the development of new devices for the detection of transgene sequences in the environment and in the food chain. In particular, PCR and, more recently, real time PCR are widely used to amplify target DNA fragments corresponding to marker genes, promoter and terminator sequences or portions of genes of interest and transgene-host integration junctions (Hernandez et al. 2003; 2005; Taverniers et al. 2004). However PCR-based techniques being prone to false positive/negative results are still time consuming, and require the sequencing of the amplified products. Recently, we have demonstrated the ability of different DNA-based sensors to detect PCR-amplified sequences complementary to part of CaMV35S viral promoter and present in transgenic Nicotiana plants (Minunni et al. 2001; Giakoumaki et al. 2003).
Here we present a method based on piezoelectric sensor for direct detection of specific sequences in the whole genomic transgenic plant DNA, suggesting that biosensors may represent an interesting and alternative candidate analytical tool for GMO traceability (Minunni et al., in press)
Detection of fragmented genomic DNA by PCR-free piezoelectric sensing using a denaturation approach
No full textDevelopment of well-automated and miniaturized gene analysis methods is the objective at which research is currently aiming. Recent works report examples of miniaturized PCR devices1 pointing at high-speed PCR. However, a great improvement in DNA sequence analysis would come by direct detection in nonamplified genomic DNA. Biosensors represent an interesting candidate for DNA detection. In particular, several DNA-based sensors have been reported. Most of the work was applied to PCR-amplified samples, and only few works, operating directly with genomic DNA, appeared in the literature with different detection principles.
In this paper, a piezoelectric sensor for direct detection of sequences in nonamplified genomic DNA is reported.
The system relies on realtime and label-free detection of the hybridization reaction between an immobilized probe (25-mer) and the complementary sequence in solution. The DNA probe is immobilized on the gold electrodes of 10 MHz quartz crystals. Genomic DNA was extracted from the plant, Nicotiana glauca, used as a model system. The target sequence was a portion of the
promoter region (35S, present in various genetically modified organisms (GMOs), used as a marker for GMO screening
Gene Delivery Markers For Gene Doping Detection: A Model Study by Affinity-Based Biosensors
No full textA DNA-based piezoelectric biosensor: strategies for coupling nucleic acids to piezoelectric devices
No full textBacterial DNA detection by QCM based sensin
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
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