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Utvärdering av extraktions och analysmetoder för lipider och fettsyror från kiselalger
No full textDet finns idag ett växande hållbarhetsrelaterat incitament att ersätta fossilbaserade och ohållbara råvaror för materialproduktion med biobaserade råvaror. Kiselalger verkar vara en lovande kandidat då de inte kräver plats på odlingsbar mark och kan odlas i restvatten eller saltvatten. Syftet med denna studie är att utvärdera lösningsmedelsextraktionprotokoll av lipider och fettsyror från Swedish Algae Factorys kiselalger, samt att undersöka hur cell lysering påverkar kvaliteten på frustulerna, eftersom dessa är företagets huvudprodukt. Fyra mekaniska metoder för cell lysering – vortex med glaspärlor, sonikering, malning med flytande kväve och krossning med metallkula via snabbt skakande – kombinerades med två lösningsmedel system: diklormetan:metanol (DCM:MeOH) och 2-metyltetrahydrofuran:isoamylalkohol (2-MeTHF:IAA). Frustulernas kvalitet bedömdes med ljusmikroskop (LM) och svepelektronmikroskop (SEM). Lipid- och fettsyra analys genomfördes med gaskromatografi med flammansjonisationsdetektor (GC-FID), tunnskiktskromatografi (TLC) samt vägning av totala lipid- och fettsyra vikten med våg. Torrvikten för cell lyseringsmetoderna varierade mellan 4.1–12.0% medan de två icke-lyserade metoderna hade en torrvikt på 7.6% och 10.4%. Cell lyseringsmetoderna hade 11–12 synliga band på TLC plattorna medan det icke-lyserade provet hade 8 band synliga, vilket kan indikera att cell lyseringen förbättrar antalet lipider och fettsyror som kan extraheras. Karaktäriseringen genomfördes genom att identifiera de större grupperna polära lipider, fria fettsyror och triacylglyceroler (TAGs). Den högsta vikten av lipider och fettsyror erhölls från provet taget efter den huvudsakliga frustule extraktionen (86.2 %), men kvaliteten på dem föreningarna undersöktes inte i denna studie. I projektet var det möjligt att extrahera lipider och fettsyror från kiselalgerna både innan och efter extraktionen av frustulerna. Resultaten behöver bekräftas med GC i framtida arbete, eftersom den analysmetoden inte gav några resultat i denna studie.There is a growing sustainability-related incentive to replace fossil-based and unsustainable feedstocks for material production with biobased feedstocks. Diatoms seem to be a promising candidate because they don’t take up arable land and can be cultivated on wastewater and saltwater. The aim of this study is to evaluate solvent extraction protocols of lipids and fatty acids from the Swedish Algae Factory’s diatoms, alongside assessing the impact of cell disruption on the frustule quality since that is the main product of the company. Four mechanical disruption techniques, vortexing with glass beads, sonication, liquid nitrogen grinding, and single‑bead beating (SBB), were combined with the two solvent systems dichloromethane:methanol (DCM: MeOH) and 2‑methyltetrahydrofuran: isoamyl alcohol (2-MeTHF: IAA). The frustule quality was assessed with light microscopy (LM) and scanning electron microscope (SEM). The lipids and fatty acids were assessed using gas chromatography equipped with a flame ionization detector (GC-FID), thin-layer chromatography (TLC) and total dry weight. The dry weight for the disruption methods ranged from 4.1–12.0% while the two non-disrupted samples had a dry weight of 7.6% and 10.4%. The disrupted samples had 11-12 visible bands on the TLC plates while the non-disrupted sample had 8 visible bands, which may indicate that cell lysis enhances the number of lipids and fatty acids that are extracted. Characterisation could be made by identifying polar lipids, free fatty acids and TAGs. The lipid yield was highest for the sample taken after the main frustule extraction (86.2%), though the quality of the compounds were not investigated. The present study shows that it is possible to extract lipids and fatty acids from the diatoms before and after extracting the frustules. Further confirmation of the results with GC needs to be performed in the future, since it did not give any results in this study
Utvärdering av extraktions och analysmetoder för lipider och fettsyror från kiselalger
No full textDet finns idag ett växande hållbarhetsrelaterat incitament att ersätta fossilbaserade och ohållbara råvaror för materialproduktion med biobaserade råvaror. Kiselalger verkar vara en lovande kandidat då de inte kräver plats på odlingsbar mark och kan odlas i restvatten eller saltvatten. Syftet med denna studie är att utvärdera lösningsmedelsextraktionprotokoll av lipider och fettsyror från Swedish Algae Factorys kiselalger, samt att undersöka hur cell lysering påverkar kvaliteten på frustulerna, eftersom dessa är företagets huvudprodukt. Fyra mekaniska metoder för cell lysering – vortex med glaspärlor, sonikering, malning med flytande kväve och krossning med metallkula via snabbt skakande – kombinerades med två lösningsmedel system: diklormetan:metanol (DCM:MeOH) och 2-metyltetrahydrofuran:isoamylalkohol (2-MeTHF:IAA). Frustulernas kvalitet bedömdes med ljusmikroskop (LM) och svepelektronmikroskop (SEM). Lipid- och fettsyra analys genomfördes med gaskromatografi med flammansjonisationsdetektor (GC-FID), tunnskiktskromatografi (TLC) samt vägning av totala lipid- och fettsyra vikten med våg. Torrvikten för cell lyseringsmetoderna varierade mellan 4.1–12.0% medan de två icke-lyserade metoderna hade en torrvikt på 7.6% och 10.4%. Cell lyseringsmetoderna hade 11–12 synliga band på TLC plattorna medan det icke-lyserade provet hade 8 band synliga, vilket kan indikera att cell lyseringen förbättrar antalet lipider och fettsyror som kan extraheras. Karaktäriseringen genomfördes genom att identifiera de större grupperna polära lipider, fria fettsyror och triacylglyceroler (TAGs). Den högsta vikten av lipider och fettsyror erhölls från provet taget efter den huvudsakliga frustule extraktionen (86.2 %), men kvaliteten på dem föreningarna undersöktes inte i denna studie. I projektet var det möjligt att extrahera lipider och fettsyror från kiselalgerna både innan och efter extraktionen av frustulerna. Resultaten behöver bekräftas med GC i framtida arbete, eftersom den analysmetoden inte gav några resultat i denna studie.There is a growing sustainability-related incentive to replace fossil-based and unsustainable feedstocks for material production with biobased feedstocks. Diatoms seem to be a promising candidate because they don’t take up arable land and can be cultivated on wastewater and saltwater. The aim of this study is to evaluate solvent extraction protocols of lipids and fatty acids from the Swedish Algae Factory’s diatoms, alongside assessing the impact of cell disruption on the frustule quality since that is the main product of the company. Four mechanical disruption techniques, vortexing with glass beads, sonication, liquid nitrogen grinding, and single‑bead beating (SBB), were combined with the two solvent systems dichloromethane:methanol (DCM: MeOH) and 2‑methyltetrahydrofuran: isoamyl alcohol (2-MeTHF: IAA). The frustule quality was assessed with light microscopy (LM) and scanning electron microscope (SEM). The lipids and fatty acids were assessed using gas chromatography equipped with a flame ionization detector (GC-FID), thin-layer chromatography (TLC) and total dry weight. The dry weight for the disruption methods ranged from 4.1–12.0% while the two non-disrupted samples had a dry weight of 7.6% and 10.4%. The disrupted samples had 11-12 visible bands on the TLC plates while the non-disrupted sample had 8 visible bands, which may indicate that cell lysis enhances the number of lipids and fatty acids that are extracted. Characterisation could be made by identifying polar lipids, free fatty acids and TAGs. The lipid yield was highest for the sample taken after the main frustule extraction (86.2%), though the quality of the compounds were not investigated. The present study shows that it is possible to extract lipids and fatty acids from the diatoms before and after extracting the frustules. Further confirmation of the results with GC needs to be performed in the future, since it did not give any results in this study
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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