Understanding the in vitro dissolution rate of glasses with respect to future clinical applications

Glass is a unique material with a long history. Several glass products are used daily in our everyday life, often unnoticed. Glass can be found not only in obvious applications such as tableware, windows, and light bulbs, but also in tennis rackets, windmill turbine blades, optical devices, and medical implants. The glasses used at present as implants are inorganic silica-based melt-derived compositions mainly for hard-tissue repair as bone graft substitute in dentistry and orthopedics. The degree of glass reactivity desired varies according to implantation situation and it is vital that the ion release from any glasses used in medical applications is controlled. Understanding the in vitro dissolution rate of glasses provides a first approximation of their behavior in vivo. Specific studies concerning dissolution properties of bioactive glasses have been relatively scarce and mostly concentrated to static condition studies. The motivation behind this work was to develop a simple and accurate method for quantifying the in vitro dissolution rate of highly different types of glass compositions with interest for future clinical applications. By combining information from various experimental conditions, a better knowledge of glass dissolution and the suitability of different glasses for different medical applications can be obtained. Thus, two traditional and one novel approach were utilized in this thesis to study glass dissolution. The chemical durability of silicate glasses was tested in water and TRIS-buffered solution at static and dynamic conditions. The traditional in vitro testing with a TRISbuffered solution under static conditions works well with bioactive or with readily dissolving glasses, and it is easy to follow the ion dissolution reactions. However, in the buffered solution no marked differences between the more durable glasses were observed. The hydrolytic resistance of the glasses was studied using the standard procedure ISO 719. The relative scale given by the standard failed to provide any relevant information when bioactive glasses were studied. However, the clear differences in the hydrolytic resistance values imply that the method could be used as a rapid test to get an overall idea of the biodegradability of glasses. The standard method combined with the ion concentration and pH measurements gives a better estimate of the hydrolytic resistance because of the high silicon amount released from a glass. A sensitive on-line analysis method utilizing inductively coupled plasma optical emission spectrometer and a flow-through micro-volume pH electrode was developed to study the initial dissolution of biocompatible glasses. This approach was found suitable for compositions within a large range of chemical durability. With this approach, the initial dissolution of all ions could be measured simultaneously and quantitatively, which gave a good overall idea of the initial dissolution rates for the individual ions and the dissolution mechanism. These types of results with glass dissolution were presented for the first time during the course of writing this thesis. Based on the initial dissolution patterns obtained with the novel approach using TRIS, the experimental glasses could be divided into four distinct categories. The initial dissolution patterns of glasses correlated well with the anticipated bioactivity. Moreover, the normalized surface-specific mass loss rates and the different in vivo models and the actual in vivo data correlated well. The results suggest that this type of approach can be used for prescreening the suitability of novel glass compositions for future clinical applications. Furthermore, the results shed light on the possible bioactivity of glasses. An additional goal in this thesis was to gain insight into the phase changes occurring during various heat treatments of glasses with three selected compositions. Engineering-type T-T-T curves for glasses 1-98 and 13-93 were stablished. The information gained is essential in manufacturing amorphous porous implants or for drawing of continuous fibers of the glasses. Although both glasses can be hot worked to amorphous products at carefully controlled conditions, 1-98 showed one magnitude greater nucleation and crystal growth rate than 13-93. Thus, 13-93 is better suited than 1-98 for working processes which require long residence times at high temperatures. It was also shown that amorphous and partially crystalline porous implants can be sintered from bioactive glass S53P4. Surface crystallization of S53P4, forming Na2O∙CaO∙2SiO2, was observed to start at 650°C. The secondary crystals of Na2Ca4(PO4)2SiO4, reported for the first time in this thesis, were detected at higher temperatures, from 850°C to 1000°C. The crystal phases formed affected the dissolution behavior of the implants in simulated body fluid. This study opens up new possibilities for using S53P4 to manufacture various structures, while tailoring their bioactivity by controlling the proportions of the different phases. The results obtained in this thesis give valuable additional information and tools to the state of the art for designing glasses with respect to future clinical applications. With the knowledge gained we can identify different dissolution patters and use this information to improve the tuning of glass compositions. In addition, the novel online analysis approach provides an excellent opportunity to further enhance our knowledge of glass behavior in simulated body conditions.

Understanding and improving quality of secondary school education : conceptions among teachers in Tanzania

Temat för studien handlar om gymnasielärares uppfattningar om kvalitet och om hur kvalitet kan utvecklas i gymnasieutbildningen in Tanzania. Studien är till sin karaktär kvalitativ och består av utprövade semistrukturerade intervjuer med sammanlagt trettio lärare som arbetar i fyra gymnasieskolor både i urbana och rurala miljöer. Lärarna har varierande arbetserfarenhet och undervisar i olika ämnen. Huvudfokus har gällt identifieringen av variationer i lärares uppfattningar om kvalitet. På basen av två forskningsfrågor avslöjar analysen uppfattningar av hur lärare förstår och önskar utveckla kvaliteten på gymnasieutbildningen. Resultaten visar att lärare förstår kvaliteten på utbildningen i sina skolor som försök att möta skolans och samhällets mål, som individuella prestationer och förmågor som att inneha kompetenser och som att möta utmaningar inom utbildning, Identifierade uppfattningar var baserade på lärarnas personliga kunskap, arbetsmiljön och varierande omständigheter som rådde i deras skolor. Uppfattningar om en förbättring av kvaliteten i gymnasieutbildningen innefattade utveckling av lärares motivation, skolmiljön, arbetet i klassrum, kvaliteten på lärares kunskaper och färdigheter och undervisningsmaterial. Ambitionen bakom studien ar att erbjuda en plattform för strategier för att förbättra kvaliteten på gymnasieutbildningen. Resultaten strävar till att ge en fördjupad insikt i uppfattningar hos en utvald grupp av lärare som arbetar under samma villkor inom gymnasieskolor I Tanzania. Av den här anledningen är den genererade kunskapen därför relevant för att belysa lärares uppfattningar även utanför den studerade gruppen av respondenter.

Knowledge, processes and relationships in organizational change: Understanding how to facilitate management of intellectual capital in diverse organization structures and cultures.

This study examined relationships of organizational dependencies, change management and developed intellectual knowledge resources, in different intellectual capital based development programs on ICT-sector. Study was carried out in a research context, where high degree of external organizational contingencies existed and lots of changes in several development programs had taken place in the last years. From a scientific perspective the main contribution was that evidence between relationships of organizational dependencies, change model portfolio and developed knowledge resources could be suggested. From managerial perspective the primary implication was that in situations where sustainable competitive advantage is pursued by means of increasing knowledge based productivity of labor, firms should seek to pursue organizational settings where external dependencies have minimal amount of effect.

Understanding, Managing And Developing A Well-Being Service Brand

The aim of this study is to analyze and understand a well-being service brand. Brands most definitely are a hot topic of today’s business world. Companies have started to realize the importance of branding, especially when talking about product related industries. Branding of services is a relatively new concept, which has gained less attention within academic literature. Though there is no legal distinction between product and service brands, they both have their own characteristics and qualities. The focus of the study is especially on the current brand images of both internal and external stakeholder groups. Understanding these brand perceptions will help in managing and developing the brand, so that it becomes even stronger, more recognized, and unified. This study is a quantitative, semi hypothetic-deductive single case study. The data for this study was collected throughout an online survey. The respondents represent both internal stakeholders, in direct contact with the service, as well as external stakeholders, who have no previous history with the service brand. The respondents represent a wide age spread, and are also geographically diverse. The study relies on a Finnish context. The study provides numerous managerial takeaways, especially because of its wide scope, on a topic that has never before been studied. All findings strongly reflected existing service brand theory, in addition with making the findings implementable for the case company.

Building organizational creativity – a multitheory and multilevel approach for understanding and stimulating organizational creativity

Organizational creativity is increasingly important for organizations aiming to survive and thrive in complex and unexpectedly changing environments. It is precondition of innovation and a driver of an organization’s performance success. Whereas innovation research increasingly promotes high-involvement and participatory innovation, the models of organizational creativity are still mainly based on an individual-creativity view. Likewise, the definitions of organizational creativity and innovation are somewhat equal, and they are used as interchangeable constructs, while on the other hand they are seen as different constructs. Creativity is seen as generation of novel and useful ideas, whereas innovation is seen as the implementation of these ideas. The research streams of innovation and organizational creativity seem to be advancing somewhat separately, although together they could provide many synergy advantages. Thereby, this study addresses three main research gaps. First, as the knowledge and knowing is being increasingly expertized and distributed in organizations, the conceptualization of organizational creativity needs to face that perspective, rather than relying on the individual-creativity view. Thus, the conceptualization of organizational creativity needs clarification, especially as an organizational-level phenomenon (i.e., creativity by an organization). Second, approaches to consciously build organizational creativity to increase the capacity of an organization to demonstrate novelty in its knowledgeable actions are rare. The current creativity techniques are mainly based on individual-creativity views, and they mainly focus on the occasional problem-solving cases among a limited number of individuals, whereas, the development of collective creativity and creativity by the organization lacks approaches. Third, in terms of organizational creativity as a collective phenomenon, the engagement, contributions, and participation of organizational members into activities of common meaning creation are more important than the individualcreativity skills. Therefore, the development approaches to foster creativity as social, emerging, embodied, and collective creativity are needed to complement the current creativity techniques. To address these gaps, the study takes a multiparadigm perspective to face the following three objectives. The first objective of this study is to clarify and extend the conceptualization of organizational creativity. The second is to study the development of organizational creativity. The third is to explore how an improvisational theater based approach fosters organizational creativity. The study consists of two parts comprising the introductory part (part I) and six publications (part II). Each publication addresses the research questions of the thesis through detailed subquestions. The study makes three main contributions to the research of organizational creativity. First, it contributes toward the conceptualization of organizational creativity by extending the current view of organizational creativity. This study views organizational creativity as a multilevel construct constituting both of individual and collective (group and organizational) creativity. In contrast to current views of organizational creativity, this study bases on organizational (collective) knowledge that is based on and demonstrated through the knowledgeable actions of an organization as a whole. The study defines organizational creativity as an overall ability of an organization to demonstrate novelty in its knowledgeable actions (through what it does and how it does what it does).Second, this study contributes toward the development of organizational creativity as multi-level phenomena, introducing developmental approaches that face two or more of these levels simultaneously. More specifically, the study presents the cross-level approaches to building organizational creativity, by using an approach based in improvisational theater and considering assessment of organizational renewal capability. Third, the study contributes on development of organizational creativity using an improvisational theater based approach as twofold meaning. First, it fosters individual and collective creativity simultaneously and builds space for creativity to occur. Second, it models collective and distributed creativity processes, thereby, contributing to the conceptualization of organizational creativity.

Interpersonal understanding and theory of mind

En populär idé inom dagens filosofiska och psykologiska forskning om interpersonlig förståelse, är idén att vi använder en kognitiv funktion (eller metod) för att förstå andra människor, en så kallad ”theory of mind” funktion. Denna idé förekommer inom ett brett vetenskapligt fält så som inom evolutionspsykologi, inom teorier om barns utveckling, inom teorier om autism, samt inom emotionsfilosofi och moralfilosofi. Avsikten i denna studie är att se närmare på vissa inflytelserika filosofiska och psykologiska teorier om interpersonlig förståelse, teorier som också har en stark koppling till empirisk forskning. I arbetet hävdar Gustafsson att teorierna ifråga avspeglar vissa klassiska, filosofiskt problematiska, antaganden. Dessa antaganden präglar teorierna ifråga samt påverkar hur de empiriska undersökningarna byggs upp och hur resultat tolkas.

Understanding Online Game Players' Post-adoption Behavior: an Investigation of Social Network Games in China

Retaining players and re-attracting switching players has long been a central topic for SNG providers with regard to the post-adoption stage of playing an online game. However, there has not been much research which has explored players’ post-adoption behavior by incorporating the continuance intention and the switching intention. In addition, traditional IS continuance theories were mainly developed to investigate users’ continued use of utilitarian IS, and thus they may fall short when trying to explain the continued use of hedonic IS. Furthermore, compared to the richer literature on IS continuance, far too little attention has been paid to IS switching, leading to a dearth of knowledge on the subject, despite the increased incidence of the switching phenomenon in the IS field. By addressing the limitations of prior literature, this study seeks to examine the determinants of SNG players’ two different post-adoption behaviors, including the continuance intention and the switching intention. This study takes a positivist approach and uses survey research method to test five proposed research models based on Unified Theory of Acceptance and Use of Technology 2; Use and Gratification Theory; Push-Pull-Mooring model; Cognitive Dissonance Theory; and a self-developed model respectively with empirical data collected from the SNG players of one of the biggest SNG providers in China. A total of 3919 valid responses and 541 valid responses were used to examine the continuance intention and the switching intention, respectively. SEM is utilized as the data analysis method. The proposed research models are supported by the empirical data. The continuance intention is determined by enjoyment, fantasy, escapism, social interaction, social presence, social influence, achievement and habit. The switching intention is determined by enjoyment, satisfaction, subjective norms, descriptive norms, alternative attractiveness, the need for variety, change experience, and adaptation cost. This study contributes to IS theories in three important ways. Firstly, it shows IS switching should be included in IS post-adoption research together with IS continuance. Secondly, a modern IS is usually multi-functional and SNG players have multiple reasons for using a SNG, thus a player’s beliefs about the hedonic, social and utilitarian perceptions of their continued use of the SNG exert significant effects on the continuance intention. Thirdly, the determinants of the switch ing intention mainly exert push, pull, and mooring effects. Players’ beliefs about their current SNG and the available alternatives, as well as their individual characteristics are all significant determinants of the switching intention. SNG players combine these effects in order to formulate the switching intention. Finally, this study presents limitations and suggestions for future research.

Guilt, shame, emotion regulation, and social cognition: Understanding their associations with preadolescents' social behavior

In this thesis, two negatively valenced emotions are approached as reflecting children’s self-consciousness, namely guilt and shame. Despite the notable role of emotions in the psychological research, empirical research findings on the links between guilt, shame, and children’s social behavior – and particularly aggression – have been modest, inconsistent, and sometimes contradictory. This thesis contains four studies on the associations of guilt, shame, emotion regulation, and social cognitions with children’s social behavior. The longitudinal material of the thesis was collected as a survey among a relatively large amount of Finnish preadolescents. In Study I, the distinctiveness of guilt and shame in children’s social behavior were investigated. The more specific links of emotions and aggressive behavior were explored in Study II, in which emotion regulation and negative emotionality were treated as the moderators between guilt, shame, and children’s aggressive behavior. The role of emotion management was further evaluated in Study III, in which effortful control and anger were treated as the moderators between domain-specific aggressive cognitions and children’s aggressive behavior. In the light of the results from the Studies II and III, it seems that for children with poor emotion management the effects of emotions and social cognitions on aggressive behavior are straight-forward, whereas effective emotion management allows for reframing the situation. Finally, in Study IV, context effects on children’s anticipated emotions were evaluated, such that children were presented a series of hypothetical vignettes, in which the child was acting as the aggressor. Furthermore, the identity of the witnesses and victim’s reactions were systematically manipulated. Children anticipated the most shame in situations, in which all of the class was witnessing the aggressive act, whereas both guilt and shame were anticipated the most in the situations, in which the victim was reacting with sadness. Girls and low-aggressive children were more sensitive to contextual cues than boys and high-aggressive children. Overall, the results of this thesis suggest that the influences of guilt, shame, and social cognition on preadolescents’ aggressive behavior depend significantly on the nature of individual emotion regulation, as well as situational contexts. Both theoretical and practical implications of this study highlight a need to acknowledge effective emotion management as enabling the justification of one’s own immoral behavior.

Analysis of the readiness of Nigerian undergraduates for eLearning courses : understanding undergraduate's perspective

There is much enthusiasm about developing eLearning coures in Nigeria, but majority of the eLearning platforms introduced from developed countries to Nigeria hardly resulted in desired outcome. Proposed reasons are lack of infrastructures such as stable electricity, inadequate rate of internet penetration, low bandwidth and low accessibility of undergraduates to sophisticated devices. These seem valid initially, but findings of this study proved otherwise. This study took a deeper evaluation of the scenarios and made viable discoveries which deviate from early findings. First, the former attempts to introduce eLearning for students in Nigeria were implemented with a rural mindset. Secondly, the undergraduate student`s technical readiness were not properly studied, also their technology user acceptance was also not properly checked and the eLearning platforms were not localized. This study conducted interviews among tertiary students at Yaba College of technology and gathered valuable information towards their readiness for eLearning.

Along-scan radiometric gradient in Landsat images: understanding the relation between floristic and remote sensing information in tropical forests

The along-scan radiometric gradient causes severe interpretation problems in Landsat images of tropical forests. It creates a decreasing trend in pixel values with the column number of the image. In practical applications it has been corrected assuming the trend to be linear within structurally similar forests. This has improved the relation between floristic and remote sensing information, but just in some cases. I use 3 Landsat images and 105 floristic inventories to test the assumption of linearity, and to examine how the gradient and linear corrections affect the relation between floristic and Landsat data. Results suggest the gradient to be linear in infrared bands. Also, the relation between floristic and Landsat data could be conditioned by the distribution of the sampling sites and the direction in which images are mosaicked. Additionally, there seems to be a conjunction between the radiometric gradient and a natural east-west vegetation gradient common in Western Amazonia. This conjunction might have enhanced artificially correlations between field and remotely-sensed information in previous studies. Linear corrections may remove such artificial enhancement, but along with true and relevant spectral information about floristic patterns, because they can´t separate the radiometric gradient from a natural one.