498 research outputs found

    A Prototype for Transforming Role-Based Access Control Models

    Get PDF
    RollipĂ”hine juurdepÀÀsukontroll on arvutisĂŒsteemides laialtkasutatav mehhanism – see tagab turvalisuse, lubades ligipÀÀsu ressurssidele vaid nendele kasutajatele, kel on selleks vastavad Ă”igused. RollipĂ”hise juurdepÀÀsukontrolli lahendusi on vĂ”imalik vĂ€lja töötada selliste modelleerimiskeelte abil, nagu SecureUML ning UMLsec, mis mĂ”lemad esitavad sĂŒsteemi disaini erinevatest vaatepunktidest. Mitme kooskĂ”lalise mudeli koostamine vĂ”ib aga osutuda keeruliseks ning aeganĂ”udvaks ĂŒlesandeks. See vĂ”ib omakorda vĂ€hendada rollipĂ”hise juurdepÀÀsukontrolli mudelite loomise motivatsiooni. Ühe lahendusena vĂ”ib pakkuda arendajale tööriista, mis kasutaks ĂŒhes keeles loodud mudelit, et selle pĂ”hjal automaatselt konstrueerida mudel teises keeles. Teisendatud mudel aga ei oleks tĂ€ielik, kuna eelmainitud keeli kasutatakse osalt erineva informatsiooni kandmiseks. Tööriista eesmĂ€rk oleks vĂ€hendada vajadust teist mudelit koostades kĂ€sitsi informatsiooni kopeerida. Selle töö raames arendatakse tööriista prototĂŒĂŒp, mis teisendab SecureUML mudeli UMLsec mudeliks ning vastupidi. See teostatakse Java programmeerimiskeeles ning pistikprogrammina professionaalsele UML modelleerimistööriistale MagicDraw. Rakendusele lisatakse menĂŒĂŒpunktid, millele vajutades kĂ€ivitatakse teisendused: SecureUML keelest UMLsec keelde vĂ”i vastupidi. Lisafunktsioonina arendatakse ka mĂ”lema mudeli tĂ€ielikkuse kontrollid, mille abil antakse kasutajale teada, kas kĂ”ik vajalikud elemendid on olemas. Need annavad kasutajale juhtnööre, kuidas teisendatud mudelit tĂ€iendada, kuna on teada, et pĂ€rast teisendust on teatud info uuelt mudelilt puudu. Teine lisakomponent vĂ”imaldab töödelda UMLsec mĂ€rgendeid (ingl. k. association tags), mis on SecureUML ning UMLsec vaheliste teisenduste tĂ€htis osa. KĂ€esoleva töö raames on koostatud ka pistikprogrammi dokumentatsioon – nĂ”uete analĂŒĂŒs, koodi dokumentatsioon ning kasutusjuhend – mille eesmĂ€rk on tagada prototĂŒĂŒbi mĂ”istmine ning aidata kaasa selle edasiarendamisele tulevikus.Role-based access control is a widely-used mechanism in computer systems – it ensures security by restricting resource access to only the system users with respective rights. The RBAC solutions can be engineered with the aid of modelling languages, such as SecureUML and UMLsec, which both present the system design from different viewpoints. Creating multiple coherent models, however, may turn out to be a non-trivial and time-consuming task. This, in turn, may dramatically lessen the motivation to create role-based access control models altogether. As a solution to the problem above, developers could be provided a software tool, which inputs a model in one language and transforms it into the model of another. The transformed model, however, would not be complete, since the two languages are used to represent somewhat different information. The aim of such a tool would be to diminish the necessity to manually copy information, when creating a second model. With this thesis, a prototype tool is developed, which enables the transformation of a SecureUML model to a UMLsec model and vice versa. The tool is implemented in the Java programming language, as a plug-in to the professional UML modelling tool MagicDraw. Menu items are added to the application, which trigger transformations: information is collected from a model in the UMLsec or SecureUML language and, based on that, a new model in the other language is created. As an additional function, completion checks are developed for both models to inform the user of whether all necessary language elements are present. They should act as guides for the user on how to improve the transformed model, since after transformations some information is known to be absent from the new model. Another additional component is the support for manipulating UMLsec association tags, which are an integral part of transformations between the SecureUML and UMLsec languages. The documentation – requirements, code documentation and user manual – is also provided in this paper and are supposed to contribute to the further development as well as understanding of the prototype

    Autoantikehad tÀppismeditsiinis

    Get PDF
    Immuuntolerantsi hĂ€irumine, mille ĂŒheks vĂ€ljundiks on antikehade teke organismile omaste biomolekulide vastu, on oluline patogeneetiline mehhanism mitmete laialdaselt levinud haiguste puhul ja seetĂ”ttu on autoantikehade mÀÀramine kujunenud oluliseks diagnostiliseks vahendiks. Artiklis on kĂ€sitletud autoantikehade esinemise olulisust haiguste tekke ja kulu prognoosimisel. Kuigi sellekohane info on veel ĂŒsna napp, on selge, et organismi immuunstaatuse muutus eelneb aastaid haiguse ilmnemisele ning autoimmuunset komponenti sisaldava haiguse kulg ja prognoos on seotud patsiendil esinevate kindlate autoantikehadega. Sellest tulenevalt vĂ”ime loota, et organismi immuunstaatuse uurimine, eriti aga autoantikehade spektri iseloomustamine, on tulevikus geneetilise info analĂŒĂŒsimise kĂ”rval ĂŒks tĂ€ppismeditsiini olulisemaid tööriistu

    Electronic health literacy in Swiss-German parents : cross-sectional study of eHealth literacy scale unidimensionality

    Get PDF
    Parents often use digital media to search for information related to their children's health. As the quantity and quality of digital sources meant specifically for parents expand, parents' digital health literacy is increasingly important to process the information they retrieve. One of the earliest developed and widely used instruments to assess digital health literacy is the self-reported eHealth Literacy Scale (eHEALS). However, the eHEALS has not been psychometrically validated in a sample of parents. Given the inconsistency of the eHEALS underlying factor structure across previous reports, it is particularly important for validation to occur

    Hidradenitis suppurativa – mĂ€dane higinÀÀrmepĂ”letik

    Get PDF
    MĂ€dane higinÀÀrmepĂ”letik ehk hidradenitis suppurativa (HS) on krooniline, Ă€genemiste ja remissioonidega kulgev ning organismi nĂ”rgestav pĂ”letikuline nahahaigus, mis lisaks nahakahjustusele vĂ”ib tekitada mĂ€rgatavaid psĂŒhhosotsiaalseid vaevusi. Kuna selle haiguse kliiniline pilt on varieeruv ning haigus haarab sageli intiimpiirkondi, vĂ”ib diagnoos hilineda aastaid. Artiklis on kĂ€sitletud selle ilmselt aladiagnoositud haiguse olemust, kliinilist pilti ning ravivĂ”imalusi

    Parental digital health information seeking behavior in Switzerland: a cross-sectional study

    Get PDF
    Digital media are increasingly abundant and used to seek health information, however, to date very little is known on parents' seeking behavior in the context of child's health and development outside English-speaking and Scandinavian countries. By investigating the prevalence of, and reasons for use, we studied parents' perception of the Internet as a resource for improving their health-related knowledge

    Resonance Theory of Decoherence and Thermalization

    Get PDF
    We present a rigorous analysis of the phenomenon of decoherence for general N−N-level systems coupled to reservoirs. The latter are described by free massless bosonic fields. We apply our general results to the specific cases of the qubit and the quantum register. We compare our results with the explicitly solvable case of systems whose interaction with the environment does not allow for energy exchange (non-demolition, or energy conserving interactions). We suggest a new approach which applies to a wide variety of systems which are not explicitly solvable

    Individuaalsed töösuhted ja nende Ôiguslik reguleerimine Eesti vabariigis aastatel 1918-1940

    Get PDF
    https://www.ester.ee/record=b5563214*es

    Dynamics of Collective Decoherence and Thermalization

    Full text link
    We analyze the dynamics of N interacting spins (quantum register) collectively coupled to a thermal environment. Each spin experiences the same environment interaction, consisting of an energy conserving and an energy exchange part. We find the decay rates of the reduced density matrix elements in the energy basis. We show that if the spins do not interact among each other, then the fastest decay rates of off-diagonal matrix elements induced by the energy conserving interaction is of order N^2, while that one induced by the energy exchange interaction is of the order N only. Moreover, the diagonal matrix elements approach their limiting values at a rate independent of N. For a general spin system the decay rates depend in a rather complicated (but explicit) way on the size N and the interaction between the spins. Our method is based on a dynamical quantum resonance theory valid for small, fixed values of the couplings. We do not make Markov-, Born- or weak coupling (van Hove) approximations

    Induction of different response patterns by differential receptor recruitment of type I interferons

    Get PDF
    FĂŒr die grundlagenorientierte Forschung sowie fĂŒr die Entwicklung neuer Wirkstoffe spielt der Mechanismus der interzellullĂ€ren Kommunikation ĂŒber Botenstoffe, wie Cytokine, eine einflussreiche Rolle. Cytokine sind Proteine, welche von Leukozyten sekretiert werden und von großer Bedeutung fĂŒr die Stimulierung des angeborenen Immunsystems sind. Hierbei bewirken die Typ I Interferone (Interferone, IFN) durch ihre antivirale, immunmodulatorische, antiproliferative und antiflammatorische Wirkung. Zudem stellen sie eine Verbindung zu der zellulĂ€ren Immunantwort dar, wirken bei antionkogenen Prozessen mit und aktivieren eine Vielzahl an weiteren Funktionen in der Zelle. Bekannt sind bisher eine Vielzahl verschiedener humaner Interferone (verschiedene IFNa-Subtypen, b, w und e), die ĂŒber einen gemeinsamen Rezeptor wirken, der sich aus den Untereinheiten ifnar1 und ifnar2 zusammensetzt. Auffallend ist, dass verschiedene Interferone unterschiedliche zellulĂ€re AktivitĂ€tsmuster induzieren. Mit dieser Arbeit sollte daher ein möglicher Zusammenhang zwischen der differentiellen Rezeptor-Rekrutierung verschiedener Interferone und der Induktion verschiedener AktivitĂ€ten geklĂ€rt werden. Voraussetzung hierfĂŒr war die Aufreinigung verschiedener Interferone (IFNa1, IFNa2, IFNa8, IFNa21, IFNb), Mutanten sowie Cystein-Mutanten zur selektiven Fluoreszenzmarkierung in ausreichender Menge und Reinheit. Um den Einfluss der BindungsaffinitĂ€t auf die AktivitĂ€t zu untersuchen, wurden AminosĂ€uren innerhalb der Bindungsstellen zu den Rezeptoruntereinheiten ausgetauscht. Die Änderung der BindungsaffinitĂ€t sowie deren Effekt auf die AktivitĂ€t wurden ĂŒberprĂŒft. Mit Hilfe der Cystein-Mutanten an der Position a2S136C / a/wS137C konnte eine ortsspezifische Fluoreszenzmarkierung durchgefĂŒhrt werden. FĂŒr die Untersuchung der Interaktion wurden die extrazellulĂ€ren DomĂ€nen von ifnar1 (ifnar1-EC) und ifnar2 (ifnar2-EC) ĂŒber einen Deka-Histidin-tag immobilisiert wurden. Die Interaktion wurde in Echtzeit mit der markierungsfreien reflektometrische Interferenzspektroskopie (RIfS) und der totalinternen Reflektions-Fluoreszenzspektroskopie (TIRFS) detektiert. Hierzu wurden die Stöchiometrie, die Kinetik der Interaktion sowie die Bindungsstelle durch Kompetition zu den Rezeptoruntereinheiten charakterisiert. Dabei zeigten sich in der Stöchiometrie (binĂ€rer/ternĂ€rer Komplex), den Bindungsstellen oder der KonformationsĂ€nderung durch ifnar1 keine Unterschiede zwischen den IFN. Als einziges Unterscheidungsmerkmal konnten signifikant unterschiedliche BindungsaffinitĂ€ten an die Rezeptoruntereinheiten ifnar1 und ifnar2 nachgewiesen werden. Dabei war die Rezeptoruntereinheit ifnar2 gegenĂŒber ifnar1 stets die höher affine Komponente mit deutlichen AffinitĂ€tsunterschieden von bis zu drei GrĂ¶ĂŸenordnungen. Ebenfalls wurde die Assemblierung eines ternĂ€ren Komplexes untersucht, fĂŒr den eine 1:1:1-Stöchiometrie fĂŒr alle IFN beobachtet wurde. FĂŒr Assemblierung ternĂ€rer Komplexe konnte ein Einfluss durch die BindungsaffinitĂ€ten sowie den relativen sowie absoluten Konzentration der Rezeptoruntereinheiten nachgewiesen werden. FĂŒr die Untersuchung verschiedener zellulĂ€rer AktivitĂ€ten, die durch die IFN induziert werden, wurde die Assemblierung des Transkriptionsfaktors ISGF3 (Interferon stimulierten Genfaktors 3), die antivirale AktivitĂ€t gegen vesikulĂ€re Stomatitis Viren (VSV) sowie die antiproliferative AktivitĂ€t ĂŒberprĂŒft. FĂŒr die ISGF3-AktivitĂ€t konnten große Unterschiede fĂŒr die effektiven Konzentrationen (EC50) zwischen den IFN beobachtet werden (pM- bis nM-Bereich). FĂŒr eine antiproliferative AktivitĂ€t wurde Konzentrationen im nM-Bereich benötigt. Insbesondere konnten Unterschiede zwischen den AktivitĂ€tsmustern beobachtet werden. Durch die Korrelation der BindungsaffinitĂ€ten mit den jeweiligen AktivitĂ€ten konnte ein deutlicher Zusammenhang beobachtet werden. So wurde fĂŒr die Induktion der ISGF3-Assemblierung eine AbhĂ€ngigkeit zu der ifnar2-AffinitĂ€t nachgewiesen. Bei niedrigen IFN-Konzentrationen wird ĂŒber die ifnar2-AffinitĂ€t die Verweildauer der Interferone auf der OberflĂ€che beeinflusst, wodurch Einfluss auf die Anzahl an ternĂ€ren Komplexen genommen wird. Im Gegensatz hierzu zeigte sich fĂŒr die antiproliferative AktivitĂ€t eine Korrelation zu der AffinitĂ€t an ifnar1. AuffĂ€llig war zudem die Korrelation der differentiellen antiproliferativen AktivitĂ€t zu der relativen BindungsaffinitĂ€t von ifnar1 zu ifnar2. Dies lĂ€sst sich durch eine mögliche Adaption der Zellen gegenĂŒber IFN erklĂ€ren, die eine Regulation der Rezeptorkonzentration auf der Membran bewirkt. Durch die Modulation der BindungsaffinitĂ€t zu ifnar2 und ifnar1 konnte der Einfluss auf die AktivitĂ€t bestĂ€tigt werden. In der Medizin könnte dies fĂŒr eine verbesserte therapeutische Anwendung von Bedeutung sein, da der Einsatz von Interferonen zurzeit durch eine Vielzahl an Nebenwirkungen eingeschrĂ€nkt ist.For development medical drugs against different diseases a better understanding of the mechanisms of intracellular communication via cytokines is important. Cytokines are proteins synthesized and secreted by leukocytes which are particular relevant for stimulating the innate immune system. Here, type I interferons (IFN) elicit an antiviral, antiproliferative or immune modulatory response. In humans different IFN (several IFNa-subtypes, IFNb, IFNw, IFNe) are known which exert their activities via one shared receptor, comprised of the subunits ifnar1 and ifnar2. Strikingly, differential response patterns are elicited by different IFN. The objective of this project was to find a correlation between differential receptor recruitment of different IFN and the induction of differential response patterns. For studying the interactions purification of different IFN (IFNa1, IFNa2, IFNa8, IFNa21, IFNw), mutants and cysteine mutants for selective fluorescence labelling in sufficient amounts and purity was established. For interaction analyses the extracellular domains of ifnar1 (ifnar1-EC) and ifnar2 (ifnar2-EC) were immobilized via decahistidine tags on different surfaces, which carried covalently attached chelator bis-NTA groups. The interaction was monitored in real time by reflectrometric interference spectroscopy (RIfS) and by total internal reflection fluorescence spectroscopy (TIRFS) in vitro. Here the stoichiometry, interaction kinetics and binding epitopes via competition to the receptor subunits was characterized. No differences were observed for stoichiometry (binary/ternary complex), binding epitopes or conformational changes of the receptor subunit ifnar1. Strikingly, for all IFNs significant differences in their binding affinities to ifnar1-EC and ifnar2-EC were observed. For the subunit ifnar2-EC a higher binding affinity was observed with differences up to three orders of magnitude compared to ifnar1-EC. The formation of the ternary complex was also studied. Furthermore the influence of receptor concentration on the stabilisation of the interferon binding in complex is examined. For examination differential cellular activities, the induction of the transcription factor ISGF3 (interferon stimulated gen factor 3), antiviral activity against vesicular stomatitis viruses (VSV) and antiproliferative activity were investigated. For ISGF3 activity strong differences between IFNs in the effective concentrations (EC50) were observed, which range from low pM to upper nM concentrations. For antiproliferative activity higher nM concentrations were necessary and a different response pattern compared to ISGF3 activity was observed. The binding affinities to ifnar2-EC and ifnar1-EC correlated with the different response patterns. Strikingly, the induction of ISGF3 activity is related to the binding affinity to ifnar2-EC. Here, the retention time of IFNs at low concentrations on the surface is increased by higher binding affinity to ifnar2-EC and so the possibility for complex assembling is increased. In contrast, the antiproliferative activity depends on the affinity to ifnar1. A striking correlation was observed for differential antiproliferative activity and the relative binding affinities towards ifnar1 and ifnar2. This was explained by differential modulation of the receptor concentration on the membran. By modulation the binding affinities the activity pattern was systematically changed, which confirms the correlation between affinity and activity
    • 

    corecore