1,720,955 research outputs found
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
Karakterizacija vpliva aminokislinskih derivatov sukcinimida na aktivnost katepsina L
Get PDFČloveški katepsin L je papainu podobna cisteinska endopeptidaza izražena v večini celic. Ima pomembno vlogo pri razgradnji proteinov, predstavitvi antigenov in regulaciji celičnega cikla. Namen naše raziskave je bil identificirati alosterične inhibitorje katepsina L. Slednji imajo prednost pred ortosteričnimi, saj zagotavljajo večjo specifičnost vezave. Kot tarčno alosterično mesto smo si izbrali tisto, kamor se dokazano vežejo alosterični efektorji na katepsinu K, ki sodi v družino katepsinu L podobnih peptidaz. Kot potencialne inhibitorje smo testirali spojine, ki so bile sintetizirane kot možni inhibitorji katepsina K in S. Testiranja smo izvedli z meritvijo aktivnosti encima s fluorogenim substratom Z-LR-AMC. Identificirali smo 12 linearnih in 5 hiperboličnih inhibitorjev. Da pa bi preverili, ali se spojina res veže v alosterično mesto, smo naredili mutanto, ki ima pet aminokislinskih ostankov v alosteričnem mestu zamenjanih s tistimi iz sorodnega katepsina V. Kot najboljši inhibitor s hiperboličnim mehanizmom delovanja se je izkazala spojina 2. Z logistično enačbo s štirimi parametri smo določili faktor EC50 670 ± 300 µM. Spojina zmanjša aktivnost encima za 30 %. Afiniteta vezave se pri mutiranih oblikah encima spremeni, zato lahko trdimo, da se veže v tarčno alosterično mesto.Human cathepsin L is a papain-like cysteine endopeptidase expressed in most cells. It plays crucial roles in protein degradation, antigen presentation and regulation of the cell cycle. Our research is focused on identifying allosteric inhibitors of cathepsin L. As our target allosteric site we choose a site where allosteric effectors bind on the related cathepsin K. We characterized the effects of potential allosteric inhibitors from a library of amino acid derivatives of succinimide that were synthesized as potential inhibitors of cathepsins K and S. By measuring the activity of cathepsin L with the synthetic fluorogenic substrate Z-LR-AMC we identified 12 linear inhibitors and 5 hyperbolic inhibitors. To test whether the inhibitors bind to the allosteric site we produced a mutant variant of cathepsin L with five amino acids in target allosteric site substituted with those from the closely related cathepsin V. The best hyperbolic inhibitor was compound 2 which lowered the activity of the enzyme by 30 % and had an EC50 value of 670 ± 300 µM for wild-type cathepsin L. The affinity of binding on mutant enzyme of chatepsin L is different so compound 2 most likely binds to allosteric site
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
Protein engineering of oligomeric states of cathepsin K
Get PDFProteinski inženiring vključuje preoblikovanje proteinov z namenom pridobitve proteina, ki bo v primerjavi z nemodificiranim izvirnikom bolj primeren za specifično aplikacijo. Na področju proteinskega inženiringa proteaz so se do sedaj ukvarjali predvsem s spreminjanjem njihove specifičnosti in izboljšanjem encimske aktivnosti, področje proteinskega inženiringa proteaz z namenom oligomerizacije pa je ostalo neraziskano.
Namen magistrske naloge je bil identificirati potencialne interakcijske površine monomerne papainu podobne cisteinske peptidaze katepsina K in pripraviti stabilni homodimer. Encim se izraža predvsem v osteoklastih kostnega tkiva, kjer je vključen v proces preoblikovanja kosti. Napake v regulaciji encimske aktivnosti katepsina K so povezane z različnimi bolezenskimi stanji, zaradi česar so struktura, funkcija in aktivnost encima podrobno raziskane. Zato je katepsin K primerna tarča za proteinski inženiring oligomernih encimskih struktur, ki bi bile napram monomerni obliki katepsina K bolj stabilne in aktivne.
V prvem koraku raziskovalnega dela smo z uporabo bioinformatskih orodij za napovedovanje interakcijskih površin in molekulsko umeščanje izračunali tri možne načine homodimerizacije katepsina K. Največjo zakopano površino je tvoril dimer, izračunan s programom SymmDock, v katerem nastane interakcija preko izolognih površin, ki vsebujeta ostanke Lys9, Pro15, Gly168 in Ile179. Nastanek in stabilnost izračunanega dimera bi bilo v prihodnosti potrebno eksperimentalno ovrednotiti.
V nadaljevanju smo v obliki rekombinantnih encimov izrazili mutanta katepsina K z vstavljenima zaporedjema, ki v katepsinu X tvorita zanki, odgovorni za dimerizacijo in stabilizacijo dimera. Mutantni obliki katepsina K nista bili encimsko aktivni, na podlagi česar smo zaključili, da vstavljeni zaporedji bistveno vplivata na zvitje proteina in/ali interakcije med prodomeno in katalitično domeno ter posledično aktivacijo cimogena. S kromatografijo z ločevanjem po velikosti smo potrdili, da eden od mutantov kljub uvedbi dimerizacijskih zank katepsina X v raztopini obstaja le v monomerni obliki. Drugi mutant, ki vsebuje le eno od dimerizacijskih zank, bi potencialno lahko tvoril dimer, vendar bi bilo njegovo strukturo potrebno podrobneje eksperimentalno ovrednotiti.Protein engineering is the process of modifying proteins with the goal of obtaining a protein that is more suitable for a particular application than the unmodified version. Protein engineering of proteases has mainly focused on modifying their specificity and improving enzyme activity, while engineering of proteases for the purpose of oligomerization has remained unexplored.
The aim of this master thesis was to identify potential protein-protein interface residues and to design a novel homodimeric state of the papain-like cysteine peptidase cathepsin K. It is highly expressed in osteoclasts as the major collagenolytic protease in bone turnover. Since its excessive activity is associated with various pathological conditions, its structure, function, and enzyme activity have been studied in detail. Therefore, cathepsin K is a suitable target for protein engineering of oligomeric states of the enzyme that would be more stable and active in comparison to monomeric state of cathepsin K.
To this end, using bioinformatics tools to predict protein-protein interface residues and molecular docking, we predicted three different possibilities for homodimerization of cathepsin K. The best computer-evaluated structure is a symmetric homodimer calculated with the program SymmDock with surface interaction residues Lys9, Pro15, Gly168 and Ile179. Its in vitro formation and stability would need to be evaluated experimentally.
Furthermore, we produced two recombinant mutant variants of cathepsin K with insertion sequences responsible for the dimerization of cathepsin X. The mutant versions of cathepsin K were inactive, from which we concluded that the insertion sequences significantly affect protein folding or prodomain - catalytic domain interactions and consequent zymogen activation. By size-exclusion chromatography, we confirmed that one of the mutants exists only in the monomeric state despite the introduction of dimerization loops. The mutant with only one dimerization loop could potentially form a dimer, but its structure would need to be further investigated
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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