1,720,954 research outputs found
The role of catalase in cell : bachelor thesis
No full textReaktivne kisikove vrste sadrže reaktivan kisik koji proizvode živi organizmi kao rezultat staničnog metabolizma. Obrambeni mehanizam koji sprječava oštećenja uzrokovana reaktivnim kisikovim vrstama predstavljaju antioksidansi koji mogu biti enzimski i neenzimski. Enzimi su proteinske molekule tercijarne ili kvarterne strukture koje imaju katalitičku sposobnost i specifičnost za određene kemijske reakcije. Katalaza je enzim iz skupine oksidoreduktaza, tetramerne je strukture i koristi se u raznim industrijama i medicini. Oksidacijski stres je neravnoteža između ROS-a i antioksidansa. Uzročnik je raznih bolesti i oštećenja molekula (DNA, lipida, proteina). Uzročnici oksidacijskog stresa, ROS, u normalnim količinama ne štete organizmima, ali u visokim koncentracijama dovode do raznih modifikacija molekula. Peroksisomi su specijalizirani organeli za provođenje reakcija oksidacije pomoću molekularnog kisika. Oni generiraju vodikov peroksid koji koriste u oksidacijske svrhe i sadrže katalazu kako bi uništili višak štetnih kisikovih spojeva. Glavna funkcija katalaze je antioksidativna. Katalaza djeluje kao agens u borbi protiv reaktivnih kisikovih spojeva i razgrađuje vodikov peroksid u vodu i kisik, te hidrolizira preko milijun molekula supstrata u sekundi. Cilj rada je ukazati na prisutnost oksidacijskog stresa, čimbenike koji ga uzrokuju i ulogu katalaze u sprječavanju oksidacijskog stresa.Reactive oxygen species contain reactive oxygen produced by living organisms as a result of cellular metabolism. The defence mechanism that prevents damage caused by reactive oxygen species is represented by antioxidants that can be enzymatic and nonenzymatic. Enzymes are protein molecules of tertiary or quaternary structure that have catalytic ability and specificity for certain chemical reactions. Catalase is enzyme from the group of oxidoreductases, it has a tetrameric structure and is use din various industries and medicine. Oxidative stress is an imbalance between ROS and antioxidants. It is the cause of various diseases and damage of molecules (DNA, lipids, proteins). The causes of oxidative stress, ROS, in normal quantities do not harm organisms, but in high concentrations they lead to various modifications of molecules. Peroxisomes are specialized for carrying out oxidation reactions using molecular oxygen, generating hydrogen peroxide and contain catalase to destroy the excess of ROS. The main function of catalase is antioxidant activity. Catalase acts as an agent in the scavenging og reactive oxygen species and decomposes hydrogen peroxide into the water and oxygen. It hydrolises over the million substrates of the molecules per second. The aim of this work is to point out the presence of oxidative stress, the factors that cause it and, conversely, the non-enzymatic and enzymatic antioxidants that can prevent it
Characterization of fennel honey by cromatografic tehnique (GcGC-MS) and spectroscopy (FTIR-ATK) : master thesis
No full textU ovom radu analiziran je kemijski sastav meda od komorača. Hlapljivi spojevi izolirani su mikroekstrakcijom vršnih para na krutoj fazi (HS-SPME) s dva različita vlakna (sivo vlakno i plavo vlakno) i ultrazvučnom ekstrakcijom organskim otapalom (USE). Analiza izoliranih hlapljivih spojeva uzoraka provedena je metodom plinska kromatografija - spektrometrija masa (GC-MS). Također je izvršena FTIR analiza gdje se dobila opća slika sastava meda od komorača. Mikroekstrakcijom vršnih para na krutoj fazi pomoću sivog vlakna izolirano je 26 hlapljivih spojeva, a pomoću plavog vlakna izolirano je 18 spojeva. Ultrazvučnom ekstrakcijom organskim otapalom izolirano je 13 spojeva. FTIR analizom je utvrđeno da ima razlike u krivulji meda od komorača i glukoznog sirupa.In this paper was, the chemical composition of fennel honey is analyzed. Volatile compounds were isolated by headspace solid phase microextraction (HS-SPME) with two different fibers (grey fiber and blue fiber) and organic solvent ultrasonic extraction (USE). The analysis of the isolated volatile compounds of the samples was performed by the gas chromatography-mass spectrometry (GC-MS) method. FTIR analysis was also performed, where a general picture of the composition of fennel honey was obtained. By microextraction of the peak pairs on the solid phase, 26 volatile compounds were isolated using the gray fiber and 18 compounds were isolated using the blue fiber. 13 compounds were isolated by ultrasonic extraction with an organic solvent. It was determined by spectroscopy (FTIR- ATR) that the curve of honey differ from the curve of glucose syrup
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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