Urban Revitalization: Remaking Cities in a Changing World

Following decades of neglect and decline, many US cities have undergone a dramatic renaissance. From New York to Nashville and Pittsburgh to Portland governments have implemented innovative redevelopment strategies to adapt to a globally integrated, post-industrial economy and cope with declining industries, tax bases, and populations - but the urban comeback has been highly uneven. Urban Revitalization integrates academic and policy research with professional knowledge and techniques. Written in an accessible style and with a thoughtful structure, it will provide graduate and upper-level undergraduate students with a comprehensive resource while also serving as a reference for professionals.

Investigation and application of methods for enumerating heterotrophs and Escherichia coli in the air within piggery sheds

Aims: To investigate methods for the recovery of airborne bacteria within pig sheds and to then use the appropriate methods to determine the levels of heterotrophs and Escherichia coli in the air within sheds. Methods and Results: AGI-30 impingers and a six-stage Andersen multi-stage sampler (AMS) were used for the collection of aerosols. Betaine and catalase were added to impinger collection fluid and the agar plates used in the AMS. Suitable media for enumerating E. coli with the Andersen sampler were also evaluated. The addition of betaine and catalase gave no marked increase in the recovery of heterotrophs or E. coli. No marked differences were found in the media used for enumeration of E. coli. The levels of heterotrophs and E. coli in three piggeries, during normal pig activities, were 2Æ2 · 105 and 21 CFU m)3 respectively. Conclusions: The failure of the additives to improve the recovery of either heterotrophs or E. coli suggests that these organisms are not stressed in the piggery environment. The levels of heterotrophs in the air inside the three Queensland piggeries investigated are consistent with those previously reported in other studies. Flushing with ponded effluent had no marked or consistent effect on the heterotroph or E. coli levels. Significance and Impact of the Study: Our work suggests that levels of airborne heterotrophs and E. coli inside pig sheds have no strong link with effluent flushing. It would seem unlikely that any single management activity within a pig shed has a dominant influence on levels of airborne heterotrophs and E. coli

Effect of surface-applied treatments on the above-ground performance of simulated timber joinery

We examined the effect of surface-applied treatments on the above-ground decay resistance of the tenon of mortice-and-tenon timber joints designed to simulate joinery that is exposed to the weather. Joints made from untreated radiata pine, Douglas-fir, brush box, spotted gum and copper-chrome-arsenic (CCA) treated radiata pine were exposed to the weather for 9 y on above-ground racks at five sites throughout eastern Australia. Results indicate (1) a poorly maintained external paint film generally accelerated decay, (2) a brush coat of water-repellent preservative inside the joints often extended serviceability (in some cases by a factor of up to seven times that of untreated joints) and (3) the level of protection provided by a coat of primer applied inside the joint varied and in most cases was not as effective as the water-repellent preservative treatment.

Phase relations in the system Ta-Rh-O and thermodynamic properties of TaRhO4

Phase relations in the system Ta-Rh-O were determined by analysis of quenched samples corresponding to thirteen compositions inside the ternary triangle after equilibration at 1273 K. All the Ta-Rh alloys were found to be in equilibrium with Ta2O5. Only one ternary oxide TaRhO4 was detected. Based on phase relations in the ternary system, a solid-state electrochemical cell, incorporating calcia-stabilized zirconia as the electrolyte, was designed to measure the standard Gibbs energy of formation (Delta G degrees, J mol(-1)) of TaRhO4 in the temperature range from 900 to 1300 K. For the reaction, 1/2 beta-Ta2O5 + 1/2 Rh2O3(ortho) -> TaRhO4 Delta G degrees = -42993 + 5.676T (+/- 85) The calculated decomposition temperatures of TaRhO4 are 1644 +/- 5K in pure O-2 and 1543 +/- 5K in air at a total pressure p(o) = 0.1 MPa. Thermodynamic properties of TaRhO4 at 298.15K have been evaluated from the results. The limited experimental thermodynamic data for Rh-rich alloys available in the literature are in fair accord with Miedema's model. The Gibbs energies of formation of the different phases in the binary system Ta-Rh were estimated based on these inputs, consistent with the binary phase diagram. Based on the thermodynamic information on the stability of various phases, an oxygen potential diagram for the system Ta-Rh-O at 1273K was constructed. Also presented are temperature-composition diagrams for the ternary system at constant oxygen partial pressures (po(2)/p(o) = 0.212 and 10(-6)) calculated form the basic data.

Guerrilla Research Tactics: Alternative Research Methods in Urban Environments

This case-study examines innovative experimentation with mobile and cloud-based technologies, utilising “Guerrilla Research Tactics” (GRT), as a means of covertly retrieving data from the urban fabric. Originally triggered by participatory action research (Kindon et al., 2008) and unobtrusive research methods (Kellehear, 1993), the potential for GRT lies in its innate ability to offer researchers an alternative, creative approach to data acquisition, whilst simultaneously allowing them to engage with the public, who are active co-creators of knowledge. Key characteristics are political agenda, the unexpected and the unconventional, which allow for an interactive, unique and thought-provoking experience for both researcher and participant.

Lionhearts of the Playworld : An ethnographic case study of the development of agency in play pedagogy

This is an ethnographic case study of the creation and emergence of a playworld – a pedagogical approach aimed at promoting children’s development and learning in early education settings through the use of play and drama. The data was collected in a Finnish experimental mixed-age elementary school classroom in the school year 2003-2004. In the playworld students and teachers explore different social and cultural phenomena through taking on the roles of characters from a story or a piece of literature and acting inside the frames of an improvised plot. The thesis takes under scrutiny the notion of agency in education. It produces theoretically grounded empirical knowledge of the ways in which children struggle to become recognized and agentive actors in early education settings and how their agency develops in their interaction with adults. The study builds on the activity theoretical and sociocultural tradition and develops a methodological framework called video-based narrative interaction analysis for studying student agency as developing over time but manifesting through the situational material and discursive local interactions. The research questions are: 1. What are the children’s ways of enacting their agency in the playworld? 2. How do the children’s agentive actions change and develop over the spring? 3. What are the potentials and challenges of the playworld for promoting student agency? 4. How do the teachers and the children deal with the contradiction between control and agency in the playworld? The study consists of a summary part and four empirical articles which each have a particular viewpoint. Articles I and II deal with individual students’ paths to agency. In Article I the focus is on the role of resistance and questioning in enabling important spaces for agency. Article II takes a critical gender perspective and analyzes how two girls struggled towards recognition in the playworld. It also illuminates the role of imagination in developing a sense of agency. Article III examines how the open-ended and improvisational nature of the playworld interaction provided experiences and a sense of ‘shared agency’ for the students and teachers in the class. Article IV turns the focus on the teachers and analyzes how their role actions in the playworld helped the children to enact agency. It also discusses the challenges that the teachers faced in this work and asks what makes the playworld activity sustainable in the class. The summary part provides a critical literature review on the concept of agency and argues that the inherently contradictory nature of the phenomenon of agency has not been sufficiently theorized. The summary part also locates the playworld intervention in a historical frame by discussing the changing conceptions of adulthood and childhood in the West. By focusing on the changing role of play and art in both adults’ and children’s contemporary lives, the thesis opens up an important but often neglected perspective on the problem of promoting student agency in education. The results illustrate how engaging in a collectively imagined and dramatized pretend play space together with the children enabled the teachers to momentarily put aside their “knower” positions in the classroom. The fictive roles and the narrative plot helped them to create a necessary incompleteness and open-endedness in the activity that stimulated the children’s initiatives. This meant that the children too could momentarily step out of their traditional classroom positions as pupils and initiate action to further the collective play. Engaging in this kind of unconventional activity and taking up and enacting agency was, however, very challenging for the participating children and teachers. It often contradicted the need to sustain control and order in the classroom. The study concludes that play- and drama-based pedagogies offer a unique but undeveloped potential for developing educational spaces that help teachers and children deal with the often contradictory requirements of schooling.

The designed environment and how it affects brain morphology and mental health

Background The environment is inextricably related to mental health. Recent research replicates findings of a significant, linear correlation between a childhood exposure to the urban environment and psychosis. Related studies also correlate the urban environment and aberrant brain morphologies. These findings challenge common beliefs that the mind and brain remain neutral in the face of worldly experience. Aim There is a signature within these neurological findings that suggests that specific features of design cause and trigger mental illness. The objective in this article is to work backward from the molecular dynamics to identify features of the designed environment that may either trigger mental illness or protect against it. Method This review analyzes the discrete functions putatively assigned to the affected brain areas and a neurotransmitter called dopamine, which is the primary target of most antipsychotic medications. The intention is to establish what the correlations mean in functional terms, and more specifically, how this relates to the phenomenology of urban experience. In doing so, environmental mental illness risk factors are identified. Conclusions Having established these relationships, the review makes practical recommendations for those in public health who wish to use the environment itself as a tool to improve the mental health of a community through design.

Improving the optimum generalised stop-and-wait ARQ scheme

Instead of waiting for the acknowledgments from all the copies of a single data block sent, as in the optimum generalised stop-and-wait ARQ scheme, the transmitter in the proposed scheme starts sending an optimum number of copies of the next block in the queue, soon after receiving the positive acknowledgment from the receiver, thereby further improving the throughput efficiency.

Nutrient levels in experimental tanks supplied with prawn pond effluent: the effect of artificial substrate and different densities of the banana prawn Penaeus merguiensis (de Man)

To experimentally investigate the effect of vertical artificial substrate and different densities of the banana prawn Penaeus (Fenneropenaeus) merguiensis on nutrient levels in prawn pond effluent, a time series experiment was conducted in a replicated tank system supplied periodically with discharge from a prawn production pond. Few differences (P>0.05) were detected between tanks without prawns, and tanks with low densities (5 prawns in 1700 litres) of prawns (10-12 g), in terms of nitrogen and phosphorus in the water column over the 28-day experimental period. Higher densities of prawns (starting at 25 or 50 per tank) caused an elevation of these macronutrients in the water column. This was partly due to prawn biomass losses from mortalities and weight reductions in the tank system. The survival and condition of prawns was significantly (P<0.05) reduced in tanks at these higher densities. The presence of artificial substrate (2 m2 tank-1) did not affect (P>0.05) the levels of nutrients in tank water columns, but significantly (P<0.05) increased the amount of nitrogen in tank residues left at the end of the trial when no prawns were present. The prawns had obviously been grazing on surfaces inside the tanks, and their swimming actions appeared to keep light particulate matter in suspension. Higher prawn densities increased microalgal blooms, which presumably kept ammonia levels low, and it is suggested that this association may provide the means for improved remediation of prawn farm effluent in the future.

The 3 Technologies

The technology scene in India is at one and the same time promising, frustrating and fascinating. Three broad areas in technology development can be distinguished. The first is relatively small scale; it is typified by the absorption of products of the industrial revolution into the repertoire of the Indian artisan and craftsman, examples being diesel engines from Kolhapur and centrifugal pumps from Coimbatore. The second class is essentially 'state technology', developed at public expense by national commissions: agriculture, atomic energy and space are examples. There is a vast third area in both private and public sector, covering products for the urban consumer and the state (e.g. r defence); this area has largely remained colonial. The factors affecting the three areas of technology are described and analysed from the point of view of an Indian scientistengineer; and it is concluded that the enormous potential of the country's human and mat.erial resources is not only unrealized, but even unrecognized as yet.

Trust, participation and health among ageing people : A cross-sectional cohort study of men and women born in 1926-30, 1936-40, and 1946-50 in the Lahti region, southern Finland

The purpose of the present study was to explore the associations between good self-rated health and economic and social factors in different regions among ageing people in the Päijät-Häme region in southern Finland. The data of this study were collected in 2002 as part of the research and development project Ikihyvä 2002 2012 (Good Ageing in Lahti region GOAL project). The baseline data set consisted of 2,815 participants born in 1926 30, 1936 40, and 1946 50. The response rate was 66 %. According to the previous studies, trust in other people and social participation as the main aspects of social capital are associated with self-rated health. In addition, socioeconomic position (SEP) and self-rated health are associated, but all SEP indicators do not have identical associations with health. However, there is a lack of knowledge of the health associations and regional differences with these factors, especially among ageing people. Regarding these questions, the present study gives new information. According to the results of this study, self-perceived adequacy of income was significantly associated with good self-rated health, especially in the urban areas. Similar associations were found in the rural areas, though education was also considered an important factor. Adequacy of income was an even stronger predictor of good health than the actual income. Women had better self-rated health than men only in the urban areas. The youngest respondents had quite equally better self-rated health than the others. Social participation and access to help when needed were associated with good self-rated health, especially in the urban area and the sparsely populated rural areas. The result was comparable in the rural population centres. The correlation of trust with self-rated health was significant in the urban area. High social capital was associated with good self-rated health in the urban area. The association was quite similar in the other areas, though it was statistically insignificant. High social capital consisted of co-existent high social participation and high trust. The association of traditionalism (low participation and high trust) with self-rated health was also substantial in the urban area. The associations of self-rated health with low social capital (low participation and low trust) and the miniaturisation of community (high participation and low trust) were less significant. From the forms of single participation, going to art exhibitions, theatre, movies, and concerts among women, and studying and self-development among men were positively related to self-rated health. Unexpectedly, among women, active participation in religious events and voluntary work was negatively associated with self-rated health. This may indicate a coping method with ill-health. As a whole, only minor variations in self-rated health were found between the areas. However, the significance of the factors associated with self-rated health varied according to the areas. Economic factors, especially self-perceived adequacy of income was strongly associated with good self-rated health. Also when adjusting for economic and several other background factors social factors (particularly high social capital, social participation, and access to help when needed) were associated with self-rated health. Thus, economic and social factors have a significant relation with the health of the ageing, and improving these factors may have favourable effects on health among ageing people.

Regenerative sustainability for the built environment – from vision to reality: An introductory chapter

Regenerative sustainability is emerging as an alternative discourse around the transition from a ‘mechanistic’ to an ‘ecological’ or living systems worldview. This view helps us to re-conceptualize relationships among humans’ technological, ecological, economic, social and political systems. Through exploration of ‘net positive’ or ‘regenerative’ development lenses and the traditional sustainability literature, the conceptualization and approaches to achieve sustainable development and ecological modernization are expanded to articulate and to explore the evolving sustainability discourse, ‘regenerative sustainability’. This Special Volume of Journal of Cleaner Production (SV) is focused upon various dimensions of regenerative sustainability (e.g. regenerative design, regenerative development, and positive development) applied to the urban built environment at scales, which range from individual buildings, neighborhoods, and urban developments to integrated regional sustainable development. The main focus is on how these approaches and developments are evolving, how they can help us to prevent or adapt to climate change and how these approaches are likely to evolve in the next two to three decades. These approaches are addressed in four themes: (1) reviewing the theoretical development of the discourse of regenerative sustainability, its emerging principles and practices, (2) explaining how it can be measured and monitored, (3) providing encouraging practical pathways and examples of its implementation in multiple cultural and climatic contexts, and (4) mapping obstacles and enablers that must be addressed to help to ensure that more rapid progress is made in implementing the transitions towards an urban built environment that supports genuinely sustainable societies.

The ozone transfer between atmosphere and vegetation. A study on Scots pine in the field

Ozone (O3) is a reactive gas present in the troposphere in the range of parts per billion (ppb), i.e. molecules of O3 in 109 molecules of air. Its strong oxidative capacity makes it a key element in tropospheric chemistry and a threat to the integrity of materials, including living organisms. Knowledge and control of O3 levels are an issue in relation to indoor air quality, building material endurance, respiratory human disorders, and plant performance. Ozone is also a greenhouse gas and its abundance is relevant to global warming. The interaction of the lower troposphere with vegetated landscapes results in O3 being removed from the atmosphere by reactions that lead to the oxidation of plant-related components. Details on the rate and pattern of removal on different landscapes as well as the ultimate mechanisms by which this occurs are not fully resolved. This thesis analysed the controlling processes of the transfer of ozone at the air-plant interface. Improvement in the knowledge of these processes benefits the prediction of both atmospheric removal of O3 and its impact on vegetation. This study was based on the measurement and analysis of multi-year field measurements of O3 flux to Scots pine (Pinus sylvestris L.) foliage with a shoot-scale gas-exchange enclosure system. In addition, the analyses made use of simultaneous CO2 and H2O exchange, canopy-scale O3, CO2 and H2O exchange, foliage surface wetness, and environmental variables. All data was gathered at the SMEAR measuring station (southern Finland). Enclosure gas-exchange techniques such as those commonly used for the measure of CO2 and water vapour can be applied to the measure of ozone gas-exchange in the field. Through analysis of the system dynamics the occurring disturbances and noise can be identified. In the system used in this study, the possible artefacts arising from the ozone reactivity towards the system materials in combination with low background concentrations need to be taken into account. The main artefact was the loss of ozone towards the chamber walls, which was found to be very variable. The level of wall-loss was obtained from simultaneous and continuous measurements, and was included in the formulation of the mass balance of O3 concentration inside the chamber. The analysis of the field measurements in this study show that the flux of ozone to the Scots pine foliage is generated in about equal proportions by stomatal and non-stomatal controlled processes. Deposition towards foliage and forest is sustained also during night and winter when stomatal gas-exchange is low or absent. The non-stomatal portion of the flux was analysed further. The pattern of flux in time was found to be an overlap of the patterns of biological activity and presence of wetness in the environment. This was seen to occur both at the shoot and canopy scale. The presence of wetness enhanced the flux not only in the presence of liquid droplets but also during existence of a moisture film on the plant surfaces. The existence of these films and their relation to the ozone sinks was determined by simultaneous measurements of leaf surface wetness and ozone flux. The results seem to suggest ozone would be reacting at the foliage surface and the reaction rate would be mediated by the presence of surface wetness. Alternative mechanisms were discussed, including nocturnal stomatal aperture and emission of reactive volatile compounds. The prediction of the total flux could thus be based on a combination of a model of stomatal behaviour and a model of water absorption on the foliage surfaces. The concepts behind the division of stomatal and non-stomatal sinks were reconsidered. This study showed that it is theoretically possible that a sink located before or near the stomatal aperture prevents or diminishes the diffusion of ozone towards the intercellular air space of the mesophyll. This obstacle to stomatal diffusion happens only under certain conditions, which include a very low presence of reaction sites in the mesophyll, an extremely strong sink located on the outer surfaces or stomatal pore. The relevance, or existence, of this process in natural conditions would need to be assessed further. Potentially strong reactions were considered, including dissolved sulphate, volatile organic compounds, and apoplastic ascorbic acid. Information on the location and the relative abundance of these compounds would be valuable. The highest total flux towards the foliage and forest happens when both the plant activity and ambient moisture are high. The highest uptake into the interior of the foliage happens at large stomatal apertures, provided that scavenging reactions located near the stomatal pore are weak or non-existent. The discussion covers the methodological developments of this study, the relevance of the different controlling factors of ozone flux, the partition amongst its component, and the possible mechanisms of non-stomatal uptake.

Impact of the Human Bacterial Environment on Mycobacteriosis and Allergy

My work describes two sectors of the human bacterial environment: 1. The sources of exposure to infectious non-tuberculous mycobacteria. 2. Bacteria in dust, reflecting the airborne bacterial exposure in environments protecting from or predisposing to allergic disorders. Non-tuberculous mycobacteria (NTM) transmit to humans and animals from the environment. Infection by NTM in Finland has increased during the past decade beyond that by Mycobacterium tuberculosis. Among the farm animals, porcine mycobacteriosis is the predominant NTM disease in Finland. Symptoms of mycobacteriosis are found in 0.34 % of slaughtered pigs. Soil and drinking water are suspected as sources for humans and bedding materials for pigs. To achieve quantitative data on the sources of human and porcine NTM exposure, methods for quantitation of environmental NTM are needed. We developed a quantitative real-time PCR method, utilizing primers targeted at the 16S rRNA gene of the genus of Mycobacterium. With this method, I found in Finnish sphagnum peat, sandy soils and mud high contents of mycobacterial DNA, 106 to 107 genome equivalents per gram. A similar result was obtained by a method based on the Mycobacterium-specific hybridization of 16S rRNA. Since rRNA is found mainly in live cells, this result shows that the DNA detected by qPCR mainly represented live mycobacteria. Next, I investigated the occurrence of environmental mycobacteria in the bedding materials obtained from 5 pig farms with high prevalence (>4 %) of mycobacteriosis. When I used for quantification the same qPCR methods as for the soils, I found that piggery samples contained non-mycobacterial DNA that was amplified in spite of several mismatches with the primers. I therefore improved the qPCR assay by designing Mycobacterium-specific detection probes. Using the probe qPCR assay, I found 105 to 107 genome equivalents of mycobacterial DNA in unused bedding materials and up to 1000 fold more in the bedding collected after use in the piggery. This result shows that there was a source of mycobacteria in the bedding materials purchased by the piggery and that mycobacteria increased in the bedding materials during use in the piggery. Allergic diseases have reached epidemic proportions in urbanized countries. At the same time, childhood in rural environment or simple living conditions appears to protect against allergic disorders. Exposure to immunoreactive microbial components in rural environments seems to prevent allergies. I searched for differences in the bacterial communities of two indoor dusts, an urban house dust shown to possess immunoreactivity of the TH2-type and a farm barn dust with TH1-activity. The immunoreactivities of the dusts were revealed by my collaborators, in vitro in human dendritic cells and in vivo in mouse. The dusts accumulated >10 years in the respiratory zone (>1.5 m above floor), thus reflecting the long-term content of airborne bacteria at the two sites. I investigated these dusts by cloning and sequencing of bacterial 16S rRNA genes from dust contained DNA. From the TH2-active urban house dust, I isolated 139 16S rRNA gene clones. The most prevalent genera among the clones were Corynebacterium (5 species, 34 clones), Streptococcus (8 species, 33 clones), Staphylococcus (5 species, 9 clones) and Finegoldia (1 species, 9 clones). Almost all of these species are known as colonizers of the human skin and oral cavity. Species of Corynebacterium and Streptococcus have been reported to contain anti-inflammatory lipoarabinomannans and immunmoreactive beta-glucans respectively. Streptococcus mitis, found in the urban house dust is known as an inducer of TH2 polarized immunity, characteristic of allergic disorders. I isolated 152 DNA clones from the TH1-active farm barn dust and found species quite different from those found from the urban house dust. Among others, I found DNA clones representing Bacillus licheniformis, Acinetobacter lwoffii and Lactobacillus each of which was recently reported to possess anti-allergy immunoreactivity. Moreover, the farm barn dust contained dramatically higher bacterial diversity than the urban house dust. Exposure to this dust thus stimulated the human dendritic cells by multiple microbial components. Such stimulation was reported to promote TH1 immunity. The biodiversity in dust may thus be connected to its immunoreactivity. Furthermore, the bacterial biomass in the farm barn dust consisted of live intact bacteria mainly. In the urban house dust only ~1 % of the biomass appeared as intact bacteria, as judged by microscoping. Fragmented microbes may possess bioactivity different from that of intact cells. This was recently shown for moulds. If this is also valid for bacteria, the different immunoreactivities of the two dusts may be explained by the intactness of dustborne bacteria. Based on these results, we offer three factors potentially contributing to the polarized immunoreactivities of the two dusts: (i) the species-composition, (ii) the biodiversity and (iii) the intactness of the dustborne bacterial biomass. The risk of childhood atopic diseases is 4-fold lower in the Russian compared with the Finnish Karelia. This difference across the country border is not explainable by different geo-climatic factors or genetic susceptibilities of the two populations. Instead, the explanation must be lifestyle-related. It has already been reported that the microbiological quality of drinking water differs on the two sides of the borders. In collaboration with allergists, I investigated dusts collected from homes in the Russian Karelia and in the Finnish Karelia. I found that bacterial 16S rRNA genes cloned from the Russian Karelian dusts (10 homes, 234 clones) predominantly represented Gram-positive taxa (the phyla Actinobacteria and Firmicutes, 67%). The Russian Karelian dusts contained nine-fold more of muramic acid (60 to 70 ng mg-1) than the Finnish Karelian dusts (3 to 11 ng mg-1). Among the DNA clones isolated from the Finnish side (n=231), Gram-negative taxa (40%) outnumbered the Gram-positives (34%). Out of the 465 DNA clones isolated from the Karelian dusts, 242 were assigned to cultured validly described bacterial species. In Russian Karelia, animal-associated species e.g. Staphylococcus and Macrococcus were numerous (27 clones, 14 unique species). This finding may connect to the difference in the prevalence of allergy, as childhood contacts with pets and farm animals have been connected with low allergy risk. Plant-associated bacteria and plant-borne 16S rRNA genes (chloroplast) were frequent among the DNA clones isolated from the Finnish Karelia, indicating components originating from plants. In conclusion, my work revealed three major differences between the bacterial communtites in the Russian and in the Finnish Karelian homes: (i) the high prevalence of Gram-positive bacteria on the Russian side and of Gram-negative bacteria on the Finnish side and (ii) the rich presence of animal-associated bacteria on the Russian side whereas (iii) plant-associated bacteria prevailed on the Finnish side. One or several of these factors may connect to the differences in the prevalence of allergy.

Organized Nanostructures of Thermoresponsive Poly(N-isopropylacrylamide) Block Copolymers Obtained Through Controlled RAFT Polymerization

Kontrolloidut radikaalipolymerointimenetelmät, kuten RAFT-polymerointi, ovat moderni tapa valmistaa polymeerejä säädellysti. RAFT-polymeroinnilla polymeerien ketjunpituutta, moolimassajakaumaa, mikrorakennetta (taktisuus, järjestys), koostumusta ja funktionaalisuutta kyetään hallitsemaan. Siten menetelmällä voidaan valmistaa uudenlaisia polymeeriarkkitektuureja, kuten blokki- ja tähtipolymeerejä, sekä hybridimateriaaleja ja biokonjugaatteja. Polymeeristen rakennuspalikoiden itsejärjestyminen, missä huolellisesti syntetisoidut polymeerit järjestyvät halutulla tavalla nanoskaalassa, on suosittu tutkimuskohde materiaalitieteessä. On huomattava, että blokkipolymeerien itsejärjestyminen on vielä suhteellisen nuori tutkimusaihe. Tämän hetkiset polymeeriset nanomateriaalit ovat suhteellisen yksinkertaisia luonnon luomuksiin verrattuina, tarjoten jatkuvasti uusia mahdollisuuksia seuraavan sukupolven polymeereille. Tässä työssä RAFT-polymeroinnilla syntetisoitiin amfifiilisiä di- ja triblokkikopolymeerejä sekä tutkittiin niiden järjestymistä nanorakenteiksi. Kaikissa blokkikopolymeereissä käytettiin lämpöherkkää poly(N-isopropyyliakryyliamidia). Siten polymeerit ja tutkitut materiaalit reagoivat lämpötilanmuutokseen ympäristössä eli ovat ns. ympäristöherkkiä. Työssä tutkittiin taktisuuden kontrollointia N-isopropyyliakryyliamidin RAFT-polymeroinnissa. Polymeerin taktisuutta sekä ketjunpituutta ja blokkijärjestystä säätämällä voitiin hallita polymeerin itsejärjestymistä vesiliuoksessa. Amfifiiliset polymeerit järjestyivät laimeissa vesiliuoksissa erilaisiksi misellirakenteiksi, muodostaen ns. mikrosäiliöitä. Tällaisilla polymeereillä odotetaan olevan sovelluksia esim. lääkeainevapautuksessa. Amfifiilejä käytetään myös esimerkiksi apuaineina pinnoitteissa ja kosmetiikassa. Kiinteässä tilassa tutkitut triblokkikopolymeerit muodostivat teoreettisesti ennustettuja morfologioita. Lämpöherkän materiaalin hydrogeelit toimivat suodatinmembraanina nanokokoluokassa. RAFT-polymeroinnilla syntetisoituja polymeereja voidaan sellaisenaan käyttää kultananopartikkeleiden päällystämiseen. Kultananopartikkelit ovat erittäin kiinostavia mm. niiden stabiilisuuden ja ainutlaatuisten pintaominaisuuksien vuoksi. Kun amfifiilisiä polymeerejä kiinnitettiin kultapartikkelin pinnalle, sen liuos- ja optisia ominaisuuksia voitiin säädellä pH:n ja lämpötilan avulla. Tällaisilla kultananopartikkeleilla on sovelluksia mm. diagnostiikassa, sensoreina ja solukuvauksessa.