1,720,959 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
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
Comparison of methods for determining mimetic activity of superoxide dismutase zinc complexes
No full textEnzim superoksid dismutaza (SOD) služi za obranu stanica protiv oksidacijskih oštećenja koja uzrokuju reaktivne kisikove vrste. SOD je metaloprotein koji pripada skupini oksidoreduktaza, a služi za regulaciju koncentracije ROS unutar organizma. S obzirom na metalne kofaktore koji su prisutni na aktivnom mjestu, postoji 4 oblika SOD: Cu,Zn-SOD, Fe-SOD, Mn-SOD i Ni-SOD. Iako je predodređen za obranu protiv ROS, enzim ima određena ograničenja te se upravo iz tog razloga koriste mimetici – sintetički spojevi koji imitiraju njegovo djelovanje. Primarno se istražuju radi terapeutske primjene za antioksidacijsko djelovanje zbog manje veličine, dužeg vremena poluživota i sličnosti u djelovanju s nativnim enzimom. Za određivanje mimetičke aktivnosti SOD cinkovih kompleksa razvijeno je nekoliko metoda. U radu su uspoređene metode za određivanje SOD mimetičke aktivnosti cinkova kompleksa . Korištene su tri neenzimatske metode od kojih se dvije temelje na alkalnom DMSO kao izvoru superoksidnih aniona, te jedna koja koristi fotoredukciju u sustavu riboflavin-metionin kako bi se generirali superoksidni anioni. Metodom 1 nije bilo moguće odrediti SOD aktivnost ispitivanog spoja, dok je Metodom 2 određena koja je iznosila 117 μM. Kod metode s fotoredukcijom riboflavina, vrijednost iznosi 228 μM iz čega se može zaključiti da je ova metoda manje osjetljiva i time manje pogodna za određivanje SOD mimetičke aktivnosti ispitivanog spoja.The enzyme superoxide dismutase (SOD) defends cells against oxidative damage caused by reactive oxygen species (ROS). SOD is a metalloprotein that belongs to the group of oxidoreductases, and serves to regulate the concentration of ROS within the organism. Considering the metal cofactors present in the active site, SOD is classified into 4 types: Cu, Zn-SOD, Fe-SOD, Mn-SOD, and Ni-SOD. Although its main role is to defend against ROS, the enzyme itself has certain limitations, therefore mimetics (synthetic compounds that mimic its action) are used as a replacement. They are primarily investigated for therapeutic purposes due to their antioxidant activity, smaller size, longer half-life and similarity in action to the native enzyme. Several methods have been developed to determine the mimetic activity of SOD zinc complexes. This thesis compares methods for determining the SOD mimetic activity of zinc complex . Three non-enzymatic methods were used, two of which are based on alkaline DMSO as a source of superoxide anions, and one which uses photoreduction of the riboflavin-methionine system to generate superoxide anions. Method 1 did not determine the SOD activity of the test compound, while Method 2 determined an of 117 μM. In the case of riboflavin photoreduction methods, the value is 228 μM, from which it can be concluded that this method is less sensitive and less suitable for determining the SOD mimetic activity of the test compound
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
Sphingolipid metabolism dysfunctions
Full text linkSfingolipidi su glavne komponente staničnih membrana u živčanom sustavu svih eukariota. S obzirom da su uklopljeni u stanične membrane, oni kontroliraju i bitne stanične signalne puteve. Najveću ulogu u staničnoj signalizaciji ima ceramid koji inducira
staničnu smrt mijenjajući pritom strukturu membrana. Ostali sfingolipidi koji su odgovorni za izgradnju dijele se na glikosfingolipide i fosfosfingolipide. Disfunkcijom metabolizma bilo kojeg sfingolipida dolazi do njihovog nakupljanja, a samim time i pojave neuroloških
oboljenja. Lizosomske bolesti nakupljanja kod kojih dolazi do pogrešne razgradnje i skladištenja tih lipida nazivaju se sfingolipidoze. Sfingolipidoze su nasljedne bolesti uzrokovane nedostatkom enzima za razgradnju ili sfingolipid aktivirajućih proteina (SAP). Iako terapije za većinu tih bolesti nisu dostupne zbog neistraženosti njihove etiologije, daljnjim istraživanjima otkrivaju se nove potencionalne metode za njihovo liječenje.Sphingolipids are the main constituents of cell membranes in the nervous system of all eukaryotes. Being embedded in the cell membranes they also control some of the most important cellular signaling pathways. Ceramide plays a major role in intracellular signaling, changing the structure of cell membranes and thereby inducing the apoptosis. The remaining sphingolipids that act as building blocks are divided into glycosphingolipids and phosphosphingolipids. Dysfunctions in sphingolipid metabolism lead to their accumulation in lysosomes, acting as a trigger for neurological disorders. Lysosomal storage diseases, which arise because of the defects in degradation and storage of sphingolipids, are called sphingolipidoses. Sphingolipidoses are a group of hereditary genetic diseases caused by a lack of sphingolipid-degrading enzymes or sphingolipid activator proteins (SAP). Treatments for most of these diseases are not yet established because of the poor understanding of their ethiologies, although, novel studies are discovering potentially new methods for their treatment
Sphingolipid metabolism dysfunctions
No full textSfingolipidi su glavne komponente staničnih membrana u živčanom sustavu svih eukariota. S obzirom da su uklopljeni u stanične membrane, oni kontroliraju i bitne stanične signalne puteve. Najveću ulogu u staničnoj signalizaciji ima ceramid koji inducira staničnu smrt mijenjajući pritom strukturu membrana. Ostali sfingolipidi koji su odgovorni za izgradnju dijele se na glikosfingolipide i fosfosfingolipide. Disfunkcijom metabolizma bilo kojeg sfingolipida dolazi do njihovog nakupljanja, a samim time i pojave neuroloških oboljenja. Lizosomske bolesti nakupljanja kod kojih dolazi do pogrešne razgradnje i skladištenja tih lipida nazivaju se sfingolipidoze. Sfingolipidoze su nasljedne bolesti uzrokovane nedostatkom enzima za razgradnju ili sfingolipid aktivirajućih proteina (SAP). Iako terapije za većinu tih bolesti nisu dostupne zbog neistraženosti njihove etiologije, daljnjim istraživanjima otkrivaju se nove potencionalne metode za njihovo liječenje.Sphingolipids are the main constituents of cell membranes in the nervous system of all eukaryotes. Being embedded in the cell membranes they also control some of the most important cellular signaling pathways. Ceramide plays a major role in intracellular signaling, changing the structure of cell membranes and thereby inducing the apoptosis. The remaining sphingolipids that act as building blocks are divided into glycosphingolipids and phosphosphingolipids. Dysfunctions in sphingolipid metabolism lead to their accumulation in lysosomes, acting as a trigger for neurological disorders. Lysosomal storage diseases, which arise because of the defects in degradation and storage of sphingolipids, are called sphingolipidoses. Sphingolipidoses are a group of hereditary genetic diseases caused by a lack of sphingolipid-degrading enzymes or sphingolipid activator proteins (SAP). Treatments for most of these diseases are not yet established because of the poor understanding of their ethiologies, although, novel studies are discovering potentially new methods for their treatment
Comparison of methods for determining mimetic activity of superoxide dismutase zinc complexes
No full textEnzim superoksid dismutaza (SOD) služi za obranu stanica protiv oksidacijskih oštećenja koja uzrokuju reaktivne kisikove vrste. SOD je metaloprotein koji pripada skupini oksidoreduktaza, a služi za regulaciju koncentracije ROS unutar organizma. S obzirom na metalne kofaktore koji su prisutni na aktivnom mjestu, postoji 4 oblika SOD: Cu,Zn-SOD, Fe-SOD, Mn-SOD i Ni-SOD. Iako je predodređen za obranu protiv ROS, enzim ima određena ograničenja te se upravo iz tog razloga koriste mimetici - sintetički spojevi koji imitiraju njegovo djelovanje. Primarno se istražuju radi terapeutske primjene za antioksidacijsko djelovanje zbog manje veličine, dužeg vremena poluživota i sličnosti u djelovanju s nativnim enzimom. Za određivanje mimetičke aktivnosti SOD cinkovih kompleksa razvijeno je nekoliko metoda. U radu su uspoređene metode za određivanje SOD mimetičke aktivnosti cinkova kompleksa . Korištene su tri neenzimatske metode od kojih se dvije temelje na alkalnom DMSO kao izvoru superoksidnih aniona, te jedna koja koristi fotoredukciju u sustavu riboflavin-metionin kako bi se generirali superoksidni anioni. Metodom 1 nije bilo moguće odrediti SOD aktivnost ispitivanog spoja, dok je Metodom 2 određena koja je iznosila 117 μM. Kod metode s fotoredukcijom riboflavina, vrijednost iznosi 228 μM iz čega se može zaključiti da je ova metoda manje osjetljiva i time manje pogodna za određivanje SOD mimetičke aktivnosti ispitivanog spoja.The enzyme superoxide dismutase (SOD) defends cells against oxidative damage caused by reactive oxygen species (ROS). SOD is a metalloprotein that belongs to the group of oxidoreductases, and serves to regulate the concentration of ROS within the organism. Considering the metal cofactors present in the active site, SOD is classified into 4 types: Cu, Zn-SOD, Fe-SOD, Mn-SOD, and Ni-SOD. Although its main role is to defend against ROS, the enzyme itself has certain limitations, therefore mimetics (synthetic compounds that mimic its action) are used as a replacement. They are primarily investigated for therapeutic purposes due to their antioxidant activity, smaller size, longer half-life and similarity in action to the native enzyme. Several methods have been developed to determine the mimetic activity of SOD zinc complexes. This thesis compares methods for determining the SOD mimetic activity of zinc complex . Three non-enzymatic methods were used, two of which are based on alkaline DMSO as a source of superoxide anions, and one which uses photoreduction of the riboflavin-methionine system to generate superoxide anions. Method 1 did not determine the SOD activity of the test compound, while Method 2 determined an of 117 μM. In the case of riboflavin photoreduction methods, the value is 228 μM, from which it can be concluded that this method is less sensitive and less suitable for determining the SOD mimetic activity of the test compound
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
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