Results of ReCap-M2a-Magnum Metal-on-Metal Total Hip Arthroplasty

Metal-on-polyethylene (MoP) bearing surfaces were standardized by Sir John Charnley and are still considered the gold standard in total hip arthroplasty (THA). Nevertheless, MoP THAs caused polyethylene wear and led to osteolysis and revisions, especially among young and active patients. Metal-on-metal (MoM) bearing surfaces were developed to solve these problems. After a brief triumph, however, poorer outcomes raised concerns over MoM THAs as well. A unique type of complication was encountered: adverse reaction to metal debris (ARMD). ARMD has been the reason for excessive failures, in MoM THA. This thesis concentrates on ReCap-M2a-Magnum MoM THA. It has comparably low revision rate of less than 10% at ten years (Australian Orthopaedic Association National Joint Replacement Registry, 2018). The aim of this thesis was to ascertain the frequency and risk factors of ARMD, assess the challenges in revision surgery, and clarify the role of whole blood cobalt and chromium metal ion levels in relation to the ReCap-M2a-Magnum device. Data was obtained from the Turku University Hospital and Oulu University Hospital electronic databases. This was the most common hip device used at Turku University Hospital from 2004 to 2012. We found a high prevalence of ARMD in a systematic screening of all of the ReCap-M2a-Magnum THA patients. Out of 1329 hips, 157 (11.8%) were considered to have definitive ARMD. In revision surgery the femoral head was frequently jammed into the stem, in 29% (20/70) of operations. Head removal was complicated, increasing operation times and intraoperative bleeding. Metal ion measurements are taken frequently during follow-up of MoM THA patients, but no increase was found in unilateral ReCap-M2a-Magnum patients over a mean 2-year interval.Sir John Charnley kehitti sementtikiinnitteisen lonkan tekonivelen, missä komponenttien liukuparina oli metalli-polyetyleeni. Tähän liukupariin on todettu liittyvän polyetyleenihiukkasten irtoamista, minkä on todettu aiheuttavan tekonivelen viereisen luun osteolyysiä. Tästä syystä myös muita liukupareja on tutkittu. Metalli-metalli-liukuparin arveltiin ratkaisevan tämän ongelman. Tästä syystä 2000-luvun alussa ko. liukuparia alettiin käyttää runsaasti lonkan tekonivelleikkauksissa. Varsin pian kuitenkin havaittiin, että tähänkin liukupariin liittyy ongelmia, narinaa, ääntelyä ja ns. metallihierreoireyhtymä (Adverse Reaction to Metal Debris = ARMD). Eri metalli-metalli-liukuparitekoniveliin liittyvät ongelmat vaihtelevat. Tässä väitöskirjassa on tutkittu ReCap-M2a-Magnum -nimisen lonkan metalli-metalli liukupari-mallia. Tähän tekonivelmalliin liittyy muita vastaavia tekonivelmalleja pienempi uusintaleikkausriski. Australian tekonivelrekisterin mukaan tämä riski on alle 10% kymmenessä vuodessa. Osatyössä 1 selvitettiin ReCap-M2a-Magnum tekonivelen nupin ja reisikomponentin kylmähitsautumisen yleisyyttä ja siitä aiheutuvia ongelmia uusintaleikkauksessa. Osatyössä 2 tutkittiin metallihierreoireyhtymän esiintyvyyttä ja sen riskitekijöitä. Osatyössä 3 tutkittiin potilaiden veren koboltti- ja kromipitoisuuksien muutoksia ko. tekonivelleikkauksen jälkeen. Osatöiden potilasaineisto on kerätty Turun yliopistollisen keskussairaalan ja Oulun yliopistollisen sairaalan tekonivelrekistereistä vuosilta 2004-2012. Tutkimusten tuloksena kylmähitsautumisilmiö ReCap-M2a-Magnum tekonivelen nupin ja reisikomponentin kartioliitoksen välissä havaittiin 29 %:ssa uusintaleikkauksia. Tämä ilmiö lisäsi leikkausaikaa ja leikkauksen aikaista veren vuotoa. Tätä tekoniveltä käyttävillä potilailla on lisääntynyt riski saada metallihierreoireyhtymä. Se todettiin 11,8 %:lla tätä tekoniveltä käyttävillä tekonivelpotilailla. Kahden vuoden seuranta-aikana koboltti- ja kromipitoisuudet eivät nouse merkittävästi ReCap-M2a-Magnum lonkan tekoniveltä käyttävillä potilailla

Electronic Patient Records in Managing Medication Information ‒ A Health Care Professional Perspective

Efficiently managed information is a key resource in clinical practice. Electronic patient records (EPRs) are in focal point in managing patient-specific medication information. In this multi-method-study, we combine qualitative and quantitative data to investigate Finnish physicians’ perceptions of EPRs. Physicians consider EPRs important in their clinical practice and use them in managing patients’ medication information while addressing a considerable dissatisfaction with quality of the current EPRs. Altogether the findings highlight the need for improving the quality of the systems and increasing the physicians’ satisfaction to materialize the benefits from the EPR

Atomic Layer Deposition and Lithium-ion Batteries : Studies on new materials and reactions for battery development

The increasing interest in both portable electronic devices and electric vehicles has given rise to a new wave of research into lithium-ion batteries. Lithium-ion batteries are the technology of choice for these applications, as they offer both high power and high energy densities. However, much research on this subject is still needed to answer the technology demands of future applications. For example, the safety concerns related to liquid electrolytes in the batteries of electric vehicles could be resolved by moving to all-solid-state batteries, which would not combust in the case of an accident. In addition, all-solid-state batteries could be manufactured into 3D structures, which would decrease the footprint area of the battery without sacrificing the amount of material. Thus, these structures would make even higher energy densities possible, which is important for example for laptops and cellphones. In addition, by combining smaller batteries with energy harvesters, such as solar cells, integrated autonomous devices could be realized. Atomic layer deposition, or ALD, is a thin film deposition method based on sequential, saturative reactions of gaseous precursors with a substrate surface. ALD generally produces highly pure films with very good thickness uniformity also in difficult, 3D substrates. Therefore, ALD should be well-suited for the deposition of Li-ion battery materials for future applications. The deposition of lithium containing materials is a fairly new avenue for ALD, the first paper being published only in 2009. It has been found that the Li-ion often bends the basic rules of ALD with its high reactivity and mobility during film growth, resulting in both unexpected reactions and film stoichiometries. This thesis provides a comprehensive review on the atomic layer deposition of lithium containing materials with a focus on the behavior of lithium in the growth process. In the experimental part, new ALD processes were developed for potential Li-ion battery materials LiF and AlF3. Both processes show reasonable ALD characteristics and produce pure films in proper deposition temperatures. In addition, conversion reactions taking place in ALD conditions were studied, and both LiF and Li3AlF6 were deposited using these reactions. The conversions were very clean, illustrated by the low impurity contents of the converted films. Lastly, the deposition of lithium containing ternary oxides was studied by heating atomic layer deposited film stacks in air. This ALD-solid state reaction -procedure resulted in pure, crystalline films of LiTaO3, LiNbO3 and Li2TiO3.Litiumioniakkuja käytetään runsaasti niin kulutuselektroniikassa (puhelimet, kannettavat tietokoneet ym.) kuin hybridi- ja sähköautoissakin. Litiumioniakut ovat valikoituneet näihin käyttökohteisiin korkeiden energia- ja tehotiheyksiensä ansiosta. Tulevaisuus tuo kuitenkin mukanaan yhä suurempia haasteita nykyisille akkuteknologioille: litiumioniakkujen nestemäisten elektrolyyttien turvallisuus on puhuttanut viime aikoina, minkä vuoksi uusia, kiinteitä epäorgaanisia elektrolyyttimateriaaleja etsitään aktiivisesti. Toisaalta uudet teknologiat vaativat yhä tehokkaampia akkuja, joten akkujen koko tulee pienenemään ja erilaiset 3D-rakenteet yleistymään. Kiinteät elektrolyyttimateriaalit ovat tärkeä osa näitä tulevaisuuden 3D-akkurakenteita. Atomikerroskasvatus eli ALD on ohutkalvojen kaasufaasikasvatusmenetelmä, jossa kaasumaiset lähdeaineet reagoivat pinnan kanssa yksi kerrallaan. Pulssittamalla pinnalle eri lähdeaineita voidaan valmistaa hyvinkin monimutkaisia kalvomateriaaleja. Atomikerroskasvatukselle on ominaista, että kalvo kasvaa erittäin toistettavasti ja tasaisesti kaikille pinnoille, joten ALD soveltuu erityisen hyvin haastavien 3D-rakenteiden pinnoittamiseen. Tämän vuoksi atomikerroskasvatus on yksi lupaavimmista menetelmistä uusien litiumioniakkumateriaalien valmistamiseen. Litiumia sisältävien materiaalien kasvattamista ALD:llä on tutkittu vasta suhteellisen lyhyen aikaa, sillä ensimmäinen aihetta käsittelevä tutkimusartikkeli julkaistiin vasta 2009. Viimeisen vuosikymmenen aikana on käynyt selväksi, että litiumionit voivat reagoida yllättävillä tavoilla ALD-kasvatusolosuhteissa. Tästä huolimatta useita potentiaalisia litiumioniakkumateriaaleja on jo kyetty valmistamaan atomikerroskasvatusta hyödyntäen. Tämän väitöskirjan kirjallisuusosuudessa on käsitelty litiumia sisältävien ohutkalvomateriaalien kasvatusta ALD-menetelmällä. Erityisenä kiinnostuksen kohteena on ollut litiumin käyttäytyminen kasvatuksen aikana. Työn kokeellisessa osassa kehitettiin uudet ALD-prosessit LiF- ja AlF3-ohutkalvojen valmistamiseksi. Molemmat prosessit tuottavat toistettavasti puhtaita ohutkalvoja. Väitöskirjatyössä tutkittiin myös litiumin vaihtoreaktioita ALD-olosuhteissa, mikä tuotti uudet prosessit LiF- ja Li3AlF6-kalvojen kasvattamiseen. Lisäksi LiTaO3-, LiNbO3- ja Li2TiO3-ohutkalvoja valmistettiin yhdistämällä ALD:tä ja kiinteän tilan reaktioita: kuumentamalla ALD-ohutkalvoja ilmassa voitiin tuottaa puhtaita, kiteisiä kalvoja

Customer Loyalty in Social Virtual Worlds

Social virtual worlds (SVWs) are an emerging phenomenon in terms of numbers of users as well as business environments. When it comes to the economic viability of SVWs, keeping existing customers active, i.e. customer loyalty, is a sine qua non. In this paper we investigate customer loyalty with two key variables: continuous use intention and purchase intention. We apply the expanded expectation-confirmation model by Thong et al. (2006) and empirically test our research model with data collected from 965 Canadian SVW users. Structural equation modelling is used to analyse the data. Perceived enjoyment was found to have the strongest impact on continuous use intentions whereas perceived critical mass was the main predictor of purchase intention. Finally, contrary to previous studies, satisfaction did not have a statistically significant impact on loyalty

EXPLORING CUSTOMERS\u27 POST-ADOPTION PERCEPTIONS: A STUDY ON TRUST, COMMITMENT AND RELATED CONSTRUCTS IN B2C ONLINE SERVICE CONTEXT

Trust has shown to be an important factor both in the adoption of e-commerce but also in ongoing relationships between buyers and sellers. Information systems literature has discussed trust extensively, yet traditionally mostly focusing on the adoption phase. However, signs of increasing interest to post-adoptive phenomena, such as customer loyalty, can be seen in the recent IS and e-commerce literature. Encouraging customers to continue the relationship after the adoption has been widely seen vital for e-businesses. This holds especially true with B2C online services where the relationships are largely based on series of transactions and interactions. The paper presents a research model in which structural assurance and online self-efficacy are viewed as the antecedents of trust, whereas trust and switching costs are investigated as the determinants of commitment. We empirically investigate a sample of active users of online services and use structural equation modeling to analyze the data. The key findings are: 1. perceived structural assurance plays an important role also after the adoption, 2. online self-efficacy was notified to be a determinant of trust, and 3. switching costs are a determinant of commitment

“Fun and Friends and Stuff” On the Stickiness of Social Virtual Worlds among Teenagers

Social Virtual Worlds (SVW) on the Internet have become increasingly popular during the past decade. Largely unnoticed by Information Systems research, Habbo Hotel, which focuses in teenage users, has advanced to become the largest SVW, boasting ten times more users than Second Life. Despite their increasing usage, business potential and societal impact, limited prior research has focused on understanding the factors that drive users to participate in SVWs. Our case study uses a largely quantitative, hypotheses-testing design to uncover the factors behind continuous SVW participation in Habbo Hotel. A research model is developed from prior IS adoption literature and tested with a sample of 844 German Habbo users using PLS. We substantiate our analysis with a qualitative examination of the reasons reported by the users. Our findings illustrate that Habbo use is driven by the stickiness of the platform, i.e. factors intrinsic to Habbo rather than external social pressure. Users engage in the SVW because of what they gain inside, not what they gain in the ‘real’ world, nor because of other people’s opinions. The qualitative analysis reveals that social experimenting is a common behavior displayed by teenagers in the virtual world. We discuss implications for IS research and practice

Digital Natives’ Purchasing Behavior in Habbo Hotel

Purchasing virtual products and services in virtual worlds is a rapidly growing form of online consumer behavior, especially among the digital natives. The paper examines why teens spend real money in virtual goods and services. We empirically investigate the reasons for virtual purchasing behavior in world‟s most popular social virtual world, Habbo Hotel. Using content analysis, we classify the reasons for purchasing into four higher order gratifications, namely elevated experience, hedonic and social factors as well as functional activities. The results demonstrate that virtual purchasing is a vehicle for enhancing and customizing the valued aspects in the user experience

THE INSTITUTIONAL LOGICS UNDERPINNING ORGANIZATIONAL AI GOVERNANCE PRACTICES

Recent developments in artificial intelligence (AI) promise significant benefits but also invoke novel risks and harms to individuals, organizations, and societies. The rising role of AI necessitates effective AI governance. However, translating AI ethics principles into governance practices remains challenging. Our paper recasts the “AI ethics translation problem” from a unidirectional translation process to a bidirectional interaction between multiple institutional logics and organizational AI governance practices. We conduct a theory adaptation study using the AI governance translation problem as a domain theory and institutional logics and institutional pluralism as method theories. Using this framework, we synthesize key AI governance practices from the literature and outline four central institutional logics: AI ethics principlism, managerial rationalism, IT professionalism, and regulatory oversight. The institutional logics and AI governance practices reciprocally influence one another: logics justify practices, and practices enact logics. We provide an illustrative analysis of the ChatGPT chatbot to demonstrate the framework. For future research, our conceptual study lays a framework for studying how plural institutional logics drive AI governance practices and how practices can be used to negotiate conflicting and complementary institutional logics

Trust, Social Presence and Customer Loyalty in Social Virtual Worlds

Social virtual worlds (SVWs) have drawn substantial attention in business and academia. This research focuses on how trust affects customer loyalty in the SVW setting. Specifically, this study pinpoints how trust in SVW staff and other users influences the continuous use and purchase behaviour in SVWs. Additionally, we examine the influence of social presence on the two aspects trust and customer loyalty. The research model is tested with PLS using a sample of 2111 Finnish Habbo users. The two facets of trust are important antecedents on customer loyalty, yet differing in their effect. Social presence is a strong determinant of trust but also a direct antecedent of customer loyalty. Together, trust and social presence account for a considerable amount of variance in continuous use and purchase intention

Escape Room as Game-Based Learning Process: Causation - Effectuation Perspective

Commercial escape rooms have provided inspiration for an increasing number of educational escape rooms, where students use their learning to solve problems and “escape” a room in a certain time. However, only few escape room studies have been published in the game-based learning research area, although it has been interested also in learning processes. In this study, we apply causation – effectuation theory to observe the learning processes of three student teams solving tasks in an escape room context. The escape room was part of an information systems science research methods course, where the learning process of 18 international students were observed on video recordings. Different learning processes were observed in the teams and causation – effectuation theory explained for example the experimental or instruction following team behavior