Thermoplastic bioactive composite ��� with special reference to dissolution behaviour and tissue response

Bioactive glasses are surface-active ceramic materials which support and accelerate bone growth in the body. During the healing of a bone fracture or a large bone defect, fixation is often needed. The aim of this thesis was to determine the dissolution behaviour and biocompatibility of a composite consisting of poly(��-caprolactone-co-DL-lactide) and bioactive glass (S53P4). In addition the applicability as an injectable material straight to a bone defect was assessed. In in vitro tests the dissolution behaviour of plain copolymer and composites containing bioactive glass granules was evaluated, as well as surface reactivity and the material���s capability to form apatite in simulated body fluid (SBF). The human fibroblast proliferation was tested on materials in cell culture. In in vivo experiments, toxicological tests, material degradation and tissue reactions were tested both in subcutaneous space and in experimental bone defects. The composites containing bioactive glass formed a unified layer of apatite on their surface in SBF. The size and amount of glass granules affected the degradation of polymer matrix, as well the material���s surface reactivity. In cell culture on the test materials the human gingival fibroblasts proliferated and matured faster compared with control materials. In in vitro tests a connective tissue capsule was formed around the specimens, and became thinner in the course of time. Foreign body cell reactions in toxicological tests were mild. In experimental bone defects the specimens with a high concentration of small bioactive glass granules (<45 ��m) formed a dense apatite surface layer that restricted the bone ingrowth to material. The range of large glass granules (90-315 ��m) with high concentrations formed the best bonding with bone, but slow degradation on the copolymer restricted the bone growth only in the superficial layers. In these studies, the handling properties of the material proved to be good and tissue reactions were mild. The reactivity of bioactive glass was retained inside the copolymer matrix, thus enabling bone conductivity with composites. However, the copolymer was noticed to degradate too slowly compared with the bone healing. Therefore, the porosity of the material should be increased in order to improve tissue healing.

Elemental analysis of wood materials by external millibeam thick target PIXE

PIXE (Particle Induce X-ray Emission spectrometry) was used for analysing stem bark and stem wood of Scots pine, Norway spruce and Silver birch. Thick samples were irradiated, in laboratory atmosphere, with 3 MeV protons and the beam current was measured indirectly using a photo multiplicator (PM) tube. Both point scans and bulk analyses were performed with the 1 mm diameter proton beam. In bulk analyses, whole bark and sectors of discs of the stem wood were dry ashed at 550 ��C. The ashes were homogenised by shaking and prepared to target pellets for PIXE analyses. This procedure generated representative samples to be analysed, but the enrichment also enabled quantification of some additional trace elements. The ash contents obtained as a product of the sample preparation procedure also showed to be of great importance in the evaluation of results in environmental studies. Spot scans from the pith of pine wood outwards, showed clearly highest concentrations of manganese, calcium and zinc in the first spot irradiated, or 2-3 times higher than in the surrounding wood. For stem wood from the crown part of a pine this higher concentration level was found in the first four spots/mms, including the pith and the two following growth rings. Zinc showed increasing concentrations outwards in sapwood of the pine stem, with the over-all lowest concentrations in the inner half of the sapwood. This could indicate emigration of this element from sapwood being under transformation to heartwood. Point scans across sapwood of pine and spruce showed more distinct variations in concentrations relative to hearth wood. Higher concentrations of e.g. zinc, calcium and manganese were found in earlywood than in denser latewood. Very high concentrations of iron and copper were also seen for some earlywood increments. The ash content of stem bark is up to and order higher than for the stem wood. However, when the elemental concentration in ashes of bark and wood of the same disc were compared, these are very similar ��� this when trees are growing at spots with no anthropogenic contamination from the atmosphere. The largest difference was obtained for calcium which appeared at two times high concentrations in ashes of bark than in ashes of the wood (ratio of 2). Pine bark is often used in monitoring of atmospheric pollution, where concentrations in bark samples are compared. Here an alternative approach is suggested: Bark and the underlying stem wood of a pine trees are dry ashed and analysed. The elemental concentration in the bark ash is then compared to the concentration of the same element in the wood ash. Comparing bark to wood includes a normalisation for the varying availability of an element from the soil at different sites. When this comparison is done for the ashes of the materials, a normalisation is also obtained for the general and locally different enrichment of inorganic elements from wood to bark. Already a ratio >2 between the concentration in the bark ash and the concentration in the wood ash could indicate atmospheric pollution. For monitoring where bark is used, this way of ���inwards��� comparison is suggested - instead of comparing to results from analyses of bark from other trees (read reference areas), growing at sites with different soil and, locally, different climate conditions. This approach also enables evaluation of atmospheric pollution from sampling of only relative few individual trees ���preferable during forest felling.

Bonding of Composite Resin to Alumina and Zirconia Ceramics with Special Emphasis on Surface Conditioning and Use of Coupling Agents

Dental oxide ceramics have been inspired by their biocompability and mechanical properties which have made durable all-ceramic structures possible. Clinical longevity of the prosthetic structures is dependent on effective bonding with luting cements. As the initial shear bond strength values can be comparable with several materials and procedures, long-term durability is affected by ageing. Aims of the current study were: to measure the shear bond strength of resin composite-to-ceramics and to evaluate the longevity of the bond; to analyze factors affecting the bond, with special emphasis on: the form of silicatization of the ceramic surface; form of silanization; type of resin primer and the effect of the type of the resin composite luting cement; the effect of ageing in water was studied regarding its effect to the endurance of the bond. Ceramic substrates were alumina and yttrium stabilized zirconia. Ceramic conditioning methods included tribochemical silicatization and use of two silane couplings agents. A commercial silane primer was used as a control silane. Various combinations of conditioning methods, primers and resin cements were tested. Bond strengths were measured by shear bond strength method. The longevity of the bond was generally studied by thermocycling the materials in water. Additionally, in one of the studies thermal cycling was compared with long-term water storaging. Results were analysed statistically with ANOVA and Weibull analysis. Tribochemical treatment utilizing air pressure of 150 kPa resulted shear bond strengths of 11.2 MPa to 18.4 MPa and air pressure of 450 kPa 18.2 MPa to 30.5 MPa, respectively. Thermocycling of 8000 cycles or four years water storaging both decreased shear bond strength values to a range of 3.8 MPa to 7.2 MPa whereas initial situation varied from 16.8. Mpa to 23.0 MPa. The silane used in studies had no statistical significance. The use of primers without 10-MDP resulted spontaneous debonding during thermocycling or shear bond strengths below 5 MPa. As conclusion, the results showed superior long-term bonding with primers containing 10-MDP. Silicatization with silanizing showed improved initial shear bond strength values which considerably decreased with ageing in water. Thermal cycling and water storing for up to four years played the major role in reduction of bond strength, which could be due to thermal fatigue of the bonding interface and hydrolytic degradation of the silane coupled interface.

Charge transport in disordered materials : simulations, theory, and numerical modeling of hopping transport and electron-hole recombination

Min avhandling behandlar hur oordnade material leder elektrisk str��m. Bland materialen som studeras finns ledande polymerer, d.v.s. plaster som leder str��m, och mer allm��nt organiska halvledare. Av de h��r materialen har man kunnat bygga elektroniska komponenter, och man hoppas p�� att kunna trycka hela kretsar av organiska material. F��r de h��r till��mpningarna ��r det viktigt att f��rst�� hur materialen sj��lva leder elektrisk str��m. Termen oordnade material syftar p�� material som saknar kristallstruktur. Oordningen g��r att elektronernas tillst��nd blir lokaliserade i rummet, s�� att en elektron i ett visst tillst��nd ��r begr��nsad t.ex. till en molekyl eller ett segment av en polymer. Det h��r kan j��mf��ras med kristallina material, d��r ett elektrontillst��nd ��r utspritt ��ver hela kristallen (men i st��llet har en v��ldefinierad r��relsem��ngd). Elektronerna (eller h��len) i det oordnade materialet kan r��ra sig genom att tunnelera mellan de lokaliserade tillst��nden. Utg��ende fr��n egenskaperna f��r den h��r tunneleringsprocessen, kan man best��mma transportegenskaperna f��r hela materialet. Det h��r ��r utg��ngspunkten f��r den s�� kallade hopptransportmodellen, som jag har anv��nt mig av. Hopptransportmodellen inneh��ller flera drastiska f��renklingar. Till exempel betraktas elektrontillst��nden som punktformiga, s�� att tunneleringssannolikheten mellan tv�� tillst��nd endast beror p�� avst��ndet mellan dem, och inte p�� deras relativa orientation. En annan f��renkling ��r att behandla det kvantmekaniska tunneleringsproblemet som en klassisk process, en slumpvandring. Trots de h��r grova approximationerna visar hopptransportmodellen ��nd�� m��nga av de fenomen som upptr��der i de verkliga materialen som man vill modellera. Man kan kanske s��ga att hopptransportmodellen ��r den enklaste modell f��r oordnade material som fortfarande ��r intressant att studera. Man har inte hittat exakta analytiska l��sningar f��r hopptransportmodellen, d��rf��r anv��nder man approximationer och numeriska metoder, ofta i form av datorber��kningar. Vi har anv��nt b��de analytiska metoder och numeriska ber��kningar f��r att studera olika aspekter av hopptransportmodellen. En viktig del av artiklarna som min avhandling baserar sig p�� ��r att j��mf��ra analytiska och numeriska resultat. Min andel av arbetet har fr��mst varit att utveckla de numeriska metoderna och applicera dem p�� hopptransportmodellen. D��rf��r fokuserar jag p�� den h��r delen av arbetet i avhandlingens introduktionsdel. Ett s��tt att studera hopptransportmodellen numeriskt ��r att direkt utf��ra en slumpvandringsprocess med ett datorprogram. Genom att f��ra statisik ��ver slumpvandringen kan man ber��kna olika transportegenskaper i modellen. Det h��r ��r en s�� kallad Monte Carlo-metod, eftersom sj��lva ber��kningen ��r en slumpm��ssig process. I st��llet f��r att f��lja r��relsebanan f��r enskilda elektroner, kan man ber��kna sannolikheten vid j��mvikt f��r att hitta en elektron i olika tillst��nd. Man st��ller upp ett system av ekvationer, som relaterar sannolikheterna f��r att hitta elektronen i olika tillst��nd i systemet med fl��det, str��mmen, mellan de olika tillst��nden. Genom att l��sa ekvationssystemet f��s sannolikhetsf��rdelningen f��r elektronerna. Fr��n sannolikhetsf��rdelningen kan sedan str��mmen och materialets transportegenskaper ber��knas. En aspekt av hopptransportmodellen som vi studerat ��r elektronernas diffusion, d.v.s. deras slumpm��ssiga r��relse. Om man betraktar en samling elektroner, s�� sprider den med tiden ut sig ��ver ett st��rre omr��de. Det ��r k��nt att diffusionshastigheten beror av elf��ltet, s�� att elektronerna sprider sig fortare om de p��verkas av ett elektriskt f��lt. Vi har unders��kt den h��r processen, och visat att beteendet ��r v��ldigt olika i endimensionella system, j��mf��rt med tv��- och tredimensionella. I tv�� och tre dimensioner beror diffusionskoefficienten kvadratiskt av elf��ltet, medan beroendet i en dimension ��r linj��rt. En annan aspekt vi studerat ��r negativ differentiell konduktivitet, d.v.s. att str��mmen i ett material minskar d�� man ��kar sp��nningen ��ver det. Eftersom det h��r fenomenet har uppm��tts i organiska minnesceller, ville vi unders��ka om fenomenet ocks�� kan uppst�� i hopptransportmodellen. Det visade sig att det i modellen finns tv�� olika mekanismer som kan ge upphov till negativ differentiell konduktivitet. Dels kan elektronerna fastna i f��llor, ��terv��ndsgr��nder i systemet, som ��r s��dana att det ��r sv��rare att ta sig ur dem d�� elf��ltet ��r stort. D�� kan elektronernas medelhastighet och d��rmed str��mmen i materialet minska med ��kande elf��lt. Elektrisk v��xelverkan mellan elektronerna kan ocks�� leda till samma beteende, genom en s�� kallad coulombblockad. En coulombblockad kan uppst�� om antalet ledningselektroner i materialet ��kar med ��kande sp��nning. Elektronerna repellerar varandra och ett st��rre antal elektroner kan leda till att transporten blir l��ngsammare, d.v.s. att str��mmen minskar.

Segregation of powder mixtures in silos with particular reference to dry mineral-based construction materials

Segregering eller segregation ��r ett fenomen som kan f��rekomma inom olika omr��den av samh��llet. Inom samh��llsvetenskaperna kan segregering definieras som det rumsliga ��tskiljandet av befolkningsgrupper p�� urval av ras eller etniskt ursprung, k��n, social h��rkomst, religion, ��lder, yrke, osv. Segregering av befolkningsgrupper sker ofta mer eller mindre frivilligt och ��r motsatsen till integration. Inom partikelteknologi definieras segregering oftast som det rumsliga ��tskiljandet av best��ndsdelarna i en blandning av olika partiklar. Segregering sker d�� p�� urval av bl.a. partiklarnas storlek, densitet, form, elektrostatiska eller mekaniska egenskaper, och kan beskrivas som motsatsen till blandning. Segregeringsmekanismer anv��nds f��r att f��rklara hur och varf��r en partikelblandning segregerar samt vad slutresultatet i form av den rumsliga f��rdelningen av partiklarna blir till f��ljd av att blandningen utsetts f��r en viss behandling. I denna avhandling har segregering av partikelblandningar och speciellt torra mineralbaserade byggmaterial (t.ex. murbruk) till f��ljd av lagring i siloer studerats. Vid industriell produktion av mineralbaserade byggmaterial anv��nds siloer f��r korttidslagring av slutprodukterna precis innan f��rpackning. Segregering leder till kraftiga variationer i sammans��ttningen f��r partikelstr��mmen ut ur silon, vilket g��r att slutprodukterna inte uppfyller kvalitetskraven och kan d��rmed inte s��ljas till kunder. Detta leder till arbetsam och dyr bearbetning (��tercirkulation) av produkterna med p��f��ljder f��r produktionsekonomin samt h��llbara utvecklingen. I avhandlingen identifierades de v��sentligaste segregeringsmekanismerna f��r torra mineralbaserade byggmaterial i siloer. Dessutom klargjordes effekterna av materialegenskaper, processbetingelser och siloparametrar. Slutligen behandlas m��jliga ��tg��rder f��r minskning av partikelsegregering i siloer samt till��mpning av matematiska metoder f��r simulering av partikelfl��den med hj��lp av datorer.

Corrosion behaviour of boiler tube materials during combustion of fuels containing Zn and Pb

M��nga f��rbr��nningsanl��ggningar som br��nner utmanande br��nslen s��som restfraktioner och avfall r��kar ut f��r problem med ��kad korrosion p�� ��verhettare och/eller vattenv��ggar pga. komponenter i br��nslena som ��r korrosiva. F��r att minimera problemen i avfallseldade pannor h��lls ��ngparametrarna p�� en relativt l��g niv��, vilket drastiskt minskar energiproduktionen. Bel��ggningarna i avfallseldade pannor best��r till st��rsta delen av element som ��r f��rknippade med h��gtemperaturkorrosion: Cl, S, alkalimetaller, fr��mst K och Na, och tungmetaller som Pb och Zn, och det finns ocks�� indikationer av Br-f��rekomst. Det l��ga ��ngtrycket i avfallseldade pannor p��verkar ocks�� st��lr��rens temperatur i pannv��ggarna i eldstaden. I dagens l��ge h��lls temperaturen normalt vid 300-400 ��C. Alkalikloridorsakad (KCl, NaCl) h��gtemperaturkorrosion har inte rapporterats vara relevant vid s��pass l��ga temperaturer, men n��rvaro av Zn- och Pb-komponenter i bel��ggningarna har p��visats f��rorsaka ��kad korrosion redan vid 300-400 ��C. Vid f��rbr��nning kan Zn och Pb reagera med S och Cl och bilda klorider och sulfater i r��kgaserna. Dessa tungmetallf��reningar ��r speciellt problematiska pga. de bildar l��gsm��ltande saltblandningar. Dessa l��gsm��ltande gasformiga eller fasta f��reningar f��ljer r��kgasen och kan sedan fastna eller kondensera p�� kallare ytor p�� pannv��ggar eller ��verhettare f��r att sedan bilda aggressiva bel��ggningar. Tungmetallrika (Pb, Zn) klorider och sulfater ��kar risken f��r korrosion, och effekten f��rst��rks ytterligare vid n��rvaro av sm��lta. Motivet med den h��r studien var att f�� en b��ttre insikt i h��gtemperaturkorrosion f��rorsakad av Zn och Pb, samt att unders��ka och prediktera beteendet och motst��ndskraften hos n��gra st��lkvaliteter som anv��nds i ��verhettare och pannv��ggar i tungmetallrika f��rh��llanden och h��ga materialtemperaturer. Omfattande laboratorie-, sm��skale- och fullskaletest utf��rdes. Resultaten kan direkt utnyttjas i praktiska applikationer, t.ex. vid materialval, eller vid utveckling av korrosionsmotverkande verktyg f��r att hitta initierande faktorer och f��rst�� deras effekt p�� h��gtemperaturkorrosion.

Sorption of metal ions to wood, pulp and bark materials

Ett huvudm��l med denna avhandling var att erh��lla ny information om v��xelverkan mellan metalljoner i vattenfas och tr��baserade material s��som olika pappersmassor, ved och bark. Material av gran, tall och bj��rk har studerats. En ny k��nslig kolonnkromatografisk metod utvecklades f��r best��mning av affinitetsordningar f��r 17 olika metalljoner. Av dessa bands trev��rt j��rn och de mycket toxiska tungmetallerna bly, koppar och kadmium starkast till de studerade materialen. V��xelverkan i dessa tv��fas system sker som jonbyte, huvudsakligen via komplexbildning av metalljoner till funktionella grupper i den fasta fasen. Vattenfasens pH ��r den viktigaste parametern som best��mmer totala halten av metalljoner som binds till materialen. Resultatet i denna avhandling kan delvis betraktas som grundforskning. En ny kunskap om metalljoners f��rekomst och kemiska reaktioner i dessa system ��r ��ven av stor ekonomisk och ekologisk, betydelse, n��r man str��var till allt mera slutna system i moderna massafabriker. Avhandlingen visar ocks�� att tr��dbark har stor potential f��r biosorption av tungmetaller t.ex. fr��n avfallsvatten. Tr��dbark har n��stan lika stor bindningskapacitet som dyra syntetiska jonbytare.

Repair of segmental bone defects with fiber-reinforced composite: a study of material development and an animal model on rabbits

The Repair of segmental defects in load-bearing long bones is a challenging task because of the diversity of the load affecting the area; axial, bending, shearing and torsional forces all come together to test the stability/integrity of the bone. The natural biomechanical requirements for bone restorative materials include strength to withstand heavy loads, and adaptivity to conform into a biological environment without disturbing or damaging it. Fiber-reinforced composite (FRC) materials have shown promise, as metals and ceramics have been too rigid, and polymers alone are lacking in strength which is needed for restoration. The versatility of the fiber-reinforced composites also allows tailoring of the composite to meet the multitude of bone properties in the skeleton. The attachment and incorporation of a bone substitute to bone has been advanced by different surface modification methods. Most often this is achieved by the creation of surface texture, which allows bone growth, onto the substitute, creating a mechanical interlocking. Another method is to alter the chemical properties of the surface to create bonding with the bone ��� for example with a hydroxyapatite (HA) or a bioactive glass (BG) coating. A novel fiber-reinforced composite implant material with a porous surface was developed for bone substitution purposes in load-bearing applications. The material���s biomechanical properties were tailored with unidirectional fiber reinforcement to match the strength of cortical bone. To advance bone growth onto the material, an optimal surface porosity was created by a dissolution process, and an addition of bioactive glass to the material was explored. The effects of dissolution and orientation of the fiber reinforcement were also evaluated for bone-bonding purposes. The Biological response to the implant material was evaluated in a cell culture study to assure the safety of the materials combined. To test the material���s properties in a clinical setting, an animal model was used. A critical-size bone defect in a rabbit���s tibia was used to test the material in a load-bearing application, with short- and long-term follow-up, and a histological evaluation of the incorporation to the host bone. The biomechanical results of the study showed that the material is durable and the tailoring of the properties can be reproduced reliably. The Biological response - ex vivo - to the created surface structure favours the attachment and growth of bone cells, with the additional benefit of bioactive glass appearing on the surface. No toxic reactions to possible agents leaching from the material could be detected in the cell culture study when compared to a nontoxic control material. The mechanical interlocking was enhanced - as expected - with the porosity, whereas the reinforcing fibers protruding from the surface of the implant gave additional strength when tested in a bone-bonding model. Animal experiments verified that the material is capable of withstanding load-bearing conditions in prolonged use without breaking of the material or creating stress shielding effects to the host bone. A Histological examination verified the enhanced incorporation to host bone with an abundance of bone growth onto and over the material. This was achieved with minimal tissue reactions to a foreign body. An FRC implant with surface porosity displays potential in the field of reconstructive surgery, especially regarding large bone defects with high demands on strength and shape retention in load-bearing areas or flat bones such as facial / cranial bones. The benefits of modifying the strength of the material and adjusting the surface properties with fiber reinforcement and bone-bonding additives to meet the requirements of different bone qualities are still to be fully discovered.

Biodegradable packaging materials in 2013 and their feasibility in chocolate industry

The development of biopolymers has been rapid in recent years and the range of available bioplastics is increasing continuously, driven by a growing demand for sustainable solutions. There are several key drivers behind this growth. The oil reservoirs are decreasing which is causing a price increase for the traditional plastic materials and therefore the gap to bioplastics��� price is getting smaller. In addition, other environmental topics, such as waste disposal and green production, have become more and more important factors for institutes, companies and consumers. Legislation and directives have to be taken into account as well in decision making concerning different packaging materials. The new environmental law with waste disposal responsibility will also have an effect on the packaging business. Therefore a need has risen to study closer the current offering closer of bio-based materials that could be used in chocolate packaging. In this Master���s Thesis the bioplastics���, and especially biodegradable materials��� technical properties and their development, availability, possible existing products in the markets, waste disposal possibilities and consumers attitude towards environmental friendly packaging is studied. This is a case study where the offering of biodegradable materials was investigated during March 2013 for Fazer Confectionary.

Development of porous glass-fiber reinforced composite for bone implants. Evaluation of antimicrobial effect and implant fixation

Cranial bone reconstructions are necessary for correcting large skull bone defects due to trauma, tumors, infections and craniotomies. Traditional synthetic implant materials include solid or mesh titanium, various plastics and ceramics. Recently, biostable glass-fiber reinforced composites (FRC), which are based on bifunctional methacrylate resin, were introduced as novel implant solution. FRCs were originally developed and clinically used in dental applications. As a result of further in vitro and in vivo testing, these composites were also approved for clinical use in cranial surgery. To date, reconstructions of large bone defects were performed in 35 patients. This thesis is dedicated to the development of a novel FRC-based implant for cranial reconstructions. The proposed multi-component implant consists of three main parts: (i) porous FRC structure; (ii) bioactive glass granules embedded between FRC layers and (iii) a silver-polysaccharide nanocomposite coating. The porosity of the FRC structure should allow bone ingrowth. Bioactive glass as an osteopromotive material is expected to stimulate the formation of new bone. The polysaccharide coating is expected to prevent bacterial colonization of the implant. The FRC implants developed in this study are based on the porous network of randomly-oriented E-glass fibers bound together by non-resorbable photopolymerizable methacrylate resin. These structures had a total porosity of 10���70 volume %, of which > 70% were open pores. The pore sizes > 100 ��m were in the biologically-relevant range (50-400 ��m), which is essential for vascularization and bone ingrowth. Bone ingrowth into these structures was simulated by imbedding of porous FRC specimens in gypsum. Results of push-out tests indicated the increase in the shear strength and fracture toughness of the interface with the increase in the total porosity of FRC specimens. The osteopromotive effect of bioactive glass is based on its dissolution in the physiological environment. Here, calcium and phosphate ions, released from the glass, precipitated on the glass surface and its proximity (the FRC) and formed bone-like apatite. The biomineralization of the FRC structure, due to the bioactive glass reactions, was studied in Simulated Body Fluid (SBF) in static and dynamic conditions. An antimicrobial, non-cytotoxic polysaccharide coating, containing silver nanoparticles, was obtained through strong electrostatic interactions with the surface of FRC. In in vitro conditions the lactose-modified chitosan (chitlac) coating showed no signs of degradation within seven days of exposure to lysozyme or one day to hydrogen peroxide (H2O2). The antimicrobial efficacy of the coating was tested against Staphylococcus aureus and Pseudomonas aeruginosa. The contact-active coating had an excellent short time antimicrobial effect. The coating neither affected the initial adhesion of microorganisms to the implant surface nor the biofilm formation after 24 h and 72 h of incubation. Silver ions released to the aqueous environment led to a reduction of bacterial growth in the culture medium.

Composite artistry in the Book of Numbers : a study in biblical narrative conventions

The present thesis discusses the coherence or lack of coherence in the book of Numbers, with special regard to its narrative features. The fragmented nature of Numbers is a well-known problem in research on the book, affecting how we approach and interpret it, but to date there has not been any thorough investigation of the narrative features of the work and how they might contribute to the coherence or the lack of coherence in the book. The discussion is pursued in light of narrative theory, and especially in connection to three parameters that are typically understood to be invoked in the interpretation of narratives: 1) a narrative paradigm, or ���story,��� meaning events related to each other temporally, causally, and thematically, in a plot with a beginning, middle, and end; 2) discourse, being the expression plane of a narrative, or the devices that an author has at hand in constructing a narrative; 3) the situation or languagegame of the narrative, prototypical examples being factual reports, which seeks to depict a state of affairs, and storytelling narratives, driven by a demand for tellability. In view of these parameters the present thesis argues that it is reasonable to form four groups to describe the narrative material of Numbers: genuine narratives (e.g. Num 12), independent narrative sequences (e.g. Num 5:1-4), instrumental scenes and situations (e.g. Num 27:1-5), and narrative fragments (e.g. Num 18:1). These groups are mixed throughout with non-narrative materials. Seen together, however, the narrative features of these groups can be understood to create an attenuated narrative sequence from beginning to end in Numbers, where one thing happens after another. This sequence, termed the ���larger story��� of Numbers, concerns the wandering of Israel from Sinai to Moab. Furthermore, the larger story has a fragmented plot. The end-point is fixed on the promised land, Israel prepares for the wandering towards it (Num 1-10), rebels against wandering and the promise and is sent back into the wilderness (Num 13-14), returns again after forty years (Num 21ff.), and prepares for conquering the land (Num 22-36). Finally, themes of the promised land, generational succession, and obedience-disobedience, operate in this larger story. Purity is also a significant theme in the book, albeit not connected to plot in the larger story. All in all, sequence, plot, and theme in the larger story of Numbers can be understood to bring some coherence to the book. However, neither aspect entirely subsumes the whole book, and the four groups of narrative materials can also be understood to underscore the incoherence of the work in differentiating its variegated narrative contents. Numbers should therefore be described as an anthology of different materials that are loosely connected through its narrative features in the larger story, with the aim of informing Israelite identity by depicting a certain period in the early history of the people.

Functionalisation of spruce O-acetyl-galactoglucomannans for barrier and composite applications

The increasing use of energy, food, and materials by the growing population in the world is leading to the situation where alternative solutions from renewable carbon resources are sought after. The growing use of plastics depends on the raw-oil production while oil refining are politically governed and required for the polymer manufacturing is not sustainable in terms of carbon footprint. The amount of packaging is also increasing. Packaging is not only utilising cardboard and paper, but also plastics. The synthetic petroleum-derived plastics and inner-coatings in food packaging can be substituted with polymeric material from the renewable resources. The trees in Finnish forests constitute a huge resource, which ought to be utilised more effectively than it is today. One underutilised component of the forests is the wood-derived hemicelluloses, although Spruce Oacetyl-galactoglucomannans (GGMs) have previously shown high potential for material applications and can be recovered in large scale. Hemicelluloses are hydrophilic in their native state, which restrains the use of them for food packaging as non-dry item. To cope with this challenge, we intended to make GGMs more hydrophobic or amphiphilic by chemical grafting and consequently with the focus of using them for barrier applications. Methods of esterification with anhydrides and cationic etherification with a trimethyl ammonium moiety were established. A method of controlled synthesis to obtain the desired properties by the means of altering temperature, reaction time, the quantity of the reagent, and even the solvent for purification of the products was developed. Numerous analytical tools, such as NMR, FTIR, SEC-MALLS/RI, MALDI-TOF-MS, RP-HPLC and polyelectrolyte titration were used to evaluate the products from different perspectives and to acquire parallel proofs of their chemical structure. Modified GGMs with different degree of substitution and the correlating level of hydrophobicity was applied as coatings on cartonboard and on nanofibrillated cellulose-GGM films to exhibit barrier functionality. The water dispersibility in processing was maintained with GGM esters with low DS. The use of chemically functionalised GGM was evaluated for the use as barriers against water, oxygen and grease for the food packaging purposes. The results show undoubtedly that GGM derivatives exhibit high potential to function as a barrier material in food packaging.