Nanoparticles combining metal oxides TiO2 and graphene derivatives (reduced graphene oxide and multi-walled carbon nanotubes) were synthesised via wet chemistry methods. The materials were investigated through a series of techniques (scanning electron microscopy, X-ray diffraction, photoluminescence and UV-visible spectrophotometry). The electronic features of the materials were examined by cyclic voltammetry, and some photocatalysis testing was performed, using a solar light simulator and Rhodamine B as a pollutant in water. It was found that addition of the graphene derivative enhanced the electrical properties of the substance, which theoretically should reflect positively in the photocatalytic skill. However, photocatalysis was not found more efficient with the composites, compared to the pristine materials. Further, SnO2@ZnO core@shell nanoparticles were synthesised by wet chemistry methods. These materials were investigated by the mentioned methods and preliminary photocatalysis testing was executed, where the composites were found functional, although further testing is required.

<p>Rikkärr är en naturtyp med hög artrikedom, som återfinns i kalkrika våtmarker. Kända rikkärr upptar idag 2-3 % av myrarealen i Sverige (Sjörs & Gunnarsson 2002). Med snabbare och effektivare inventeringsmetoder skulle med all sannolikhet fler rikkärr återfinnas. Rikkärrens många arter har under lång tid anpassat sig till de speciella förhållandena men är idag starkt hotade då biotopen rikkärr minskar. Tillbakagången är ett resultat av dikning, upphörd hävd, övergödning, försurning och skogsbruk. I de svenska rikkärren finns många rödlistade och utrotningshotade arter inom grupperna snäckor, kärlväxter och mossor. För att bevara den biologiska mångfalden behöver vi ha säkra metoder för att identifiera rikkärr och på så vis ha möjlighet att skydda dem. Naturtypen rikkärr har många fysionomier som gör den svår att urskilja vid flygbildstolkning. Syftet med examensarbetet är att undersöka om det med hjälp av geologiska data hos Sveriges geologiska undersökning (SGU) är möjligt att finna kopplingar till rikkärren som kan användas för att på ett säkert sätt kunna identifiera potentiella rikkärrsområden snabbare i framtiden. Arbetet har genomförts genom att studera samband mellan utvalda element ur ett antal undersökningar utförda av SGU. Resultatet visar tydligt det starka samband rikkärren har till områden med kalkberggrund och på hur tydligt detta syns vid användandet av det geografiska informationsprogrammet ArcGIS. Resultaten i uppsatsen tydliggör även svårigheten med att använda befintliga data, ur SGU:s geodatabas, för att finna kompletterade komponenter med samband till biotopen rikkärr. Resultaten leder till rekommendationer om framtida undersökningar att utföra för att stärka vår kunskap om rikkärren.</p> / Kan SGUs data användas för att förutsäga vegetationens sammansättning?

<p>Syftet med denna fallstudie är att undersöka lärares inställning till och undervisning i naturvetenskap för att därefter koppla detta till lärarnas upplevda erfarenheter av barns intresse för naturvetenskap.</p><p>Metoden som har används är en empirisk undersökning och semistrukturerade personintervjuer. Resultatet visade att samtliga lärare som deltog i undersökningen hade en positiv inställning till de naturvetenskapliga ämnena. De ansåg att eleverna var mycket intresserade och att de tyckte att det var intressant med naturvetenskaplig undervisning. Slutsatsen är att lärarna ansåg att problemen med den naturvetenskapliga undervisngen är material, det finns inget eller dåligt på skolorna. Sedan visar undersökningen att de barnen i de tidigare åren är intresserade av naturvetenskap men att något händer under högstadiet som gör att detta intresse försvinner hos många elever.</p>

<p>The purpose of this essay is to find an answer to whether the methodology used by the Naturskolan conduces to learning and also if the Naturskolan, as a method of its own, leads to an increased interest in natural science for the pupils participating in the classes at the Naturskolan.</p><p>The method which has been used to reach the results of the study is a quantitative opinion poll. The results reached through the study has been compared to previous research in the subject. Deeper studies were made to examine however the interest of the pupils was influenced by their visit at the Naturskolan.</p><p>The results of the study show an increase of interest in natural science after visiting the Naturskolan. It also shows that the teachers’ interest in natural science and outdoor pedagogy has increased by the visit at the Naturskolan.</p><p>Through this study we came to the conclusion that the Naturskolan is a good method to learning.</p>

<p><strong>Sammanfattning</strong></p><p><strong>Kånneby är doktorand på Naturhistoriska riksmuseet i Stockholm. Han har skrivit en ny</strong></p><p><strong>publikation om bukhårsdjur (Gastrotricha). Målgruppen är forskare inom biologi, zoologi</strong></p><p><strong>och studenter. Publikationen innehåller bland annat beskrivning av en ny art och tre arter</strong></p><p><strong>som hittas för första gången i Sverige samt en identifieringsnyckel över släktet <em>Ihthydium</em>.</strong></p><p><strong>Syftet med arbetet har varit att underlätta det visuella tänkandet för målgruppen genom att</strong></p><p><strong>lyfta in illustrationer, som passar till publikationen. Det för att publikationen skulle fungera</strong></p><p><strong>optimalt.</strong></p><p><strong>De illustrationer som behövdes diskuterade jag och Kånneby tillsammans fram. Det</strong></p><p><strong>behövdes illustrationer till publikationens identifieringsnyckel och till den nya arten.</strong></p><p><strong>En uppgift tillkom mitt under arbetsgången som skulle stödja publikationen ytterligare,</strong></p><p><strong>en samlingsbild över bukhårsdjurets anatomi. Kånneby ville också ha en visuell målning</strong></p><p><strong>av bukhårsdjuret i dess naturliga miljö. Det blev en uppgift som gjordes fastän den inte var</strong></p><p><strong>nödvändig för publikationens användbarhet.</strong></p><p><strong>Illustrationerna har utförts med hjälp av mycket underlag och diskussioner. Fakta som</strong></p><p><strong>stödjer mina teorier är hämtade ur litteratur. Praktiskt arbete har genomförts för hand med</strong></p><p><strong>valda pennor, akvarell och med dator.</strong></p><p><strong>I rapporten redogörs de teorier och metoder som har varit lämpliga för att lösa uppgifterna</strong></p><p><strong>samt arbetsgången för varje uppgift. En utprovning har gjorts och resultat redogörs och</strong></p><p><strong>visas även i bilagor.</strong></p><p><strong>Arbetet har utförts på Naturhistoriska riksmuseet i Stockholm under perioden</strong></p><p><strong>2009-03-24 - 2009-05-21.</strong></p><p><strong>Publikation,</strong></p>

<p>This Thesis treats the growth and characterization of ternary transition metal nitride thin films. The aim is to probe deeper into the Ti-Al-N system and to explore the novel Sc-Al-N system. Thin films were epitaxially grown by reactive magnetron sputtering from elemental targets onto single-crystal substrates covered with a seed layer. Elastic recoil detection analysis and Rutherford backscattering spectroscopy were used for compositional analysis and depth profiling. Different x-ray diffraction techniques were employed, ex situ using Cu radiation and in situ during deposition using synchrotron radiation, to identify phases, to obtain information about texture, and to determine the thickness and roughness evolution of layers during and after growth. Transmission electron microscopy was used for overview and lattice imaging, and to obtain lattice structure information by electron diffraction. Film properties were determined using van der Pauw measurements of the electrical resistivity, and nanoindentation for the materials hardness and elastic modulus. The epitaxial M_n+1AX_n phase Ti₂AlN was synthesized by solid-state reaction during interdiffusion between sequentially deposited layers of (0001)-oriented AlN and Ti thin films. When annealing the sample, N and Al diffused into the Ti, forming Ti₃AlN at 400 ºC and Ti2AlN at 500 ºC. The Ti₂AlN formation temperature is 175 ºC lower than earlier reported results. Ti₄AlN₃ thin films were, however, not possible to synthesize when depositing films with a Ti:Al:N ratios of 4:1:3. Substrate temperatures at 600 ºC yielded an irregularly stacked Tin+1AlNn layered structure because of the low mobility of Al adatoms. An increased temperature led, however, to an Al deficiency due to an out diffusion of Al atoms, and formation of Ti₂AlN phase and Ti_1-xAlx_N cubic solid solution. In the Sc-Al-N system the first ternary phase was discovered, namely the perovskite Sc₃AlN, with a unit cell of 4.40 Å. Its existence was supported by ab initio calculations of the enthalpy showing that Sc3AlN is thermodynamically stable with respect to the binaries. Sc3AlN thin films were experimentally found to have a hardness of 14.2 GPa, an elastic modulus of 21 GPa, and a room temperature resistivity of 41.2 μΩcm.</p>

<p>The semi-conductor zinc oxide (ZnO), a representative of group II-VI has gained substantial interest in the research community due to its novel properties and characteristics. ZnO a direct band gap (3.4eV) semi-conductor has a stable wurtzite structure. Recently ZnO have attracted much interest because of its unique piezoelectric, semiconducting, catalytic properties and being biosafe and biocompatible morphology combined with the easiness of growth. This implies that ZnO has a wide range of applications in optoelectronics, sensors, transducers, energy conversion and medical sciences. This thesis relates specifically to biosensor technology and pertains more particularly to novel biosensors based on multifunctional ZnO nanorods for biological, biochemical and chemical applications.</p><p>The nanoscale science and engineering have found great promise in the fabrication of novel nano-biosensors with faster response and higher sensitivity than of planar sensor configurations. This thesis aims to highlight recent developments in materials and techniques for electrochemical biosensing, design, operation and fabrication. Rapid research growths in biomaterials, especially the availability and applications of a vast range of polymers and copolymers associated with new sensing techniques have led to remarkable innovation in the design and fabrication of biosensors. Specially nanowires/nanorods and due to their small dimensions combined with dramatically increased contact surface and strong binding with biological and chemical reagents will have important applications in biological and biochemical research. The diameter of these nanostructures is usually comparable to the size of the biological and chemical species being sensed, which intuitively makes them represent excellent primary transducers for producing electrical signals. ZnO nanostructures have unique advantages including high surface to volume ratio, nontoxicity, chemical stability, electrochemical activity, and high electron communication features. In addition, ZnO can be grown as vertical nanorods and has high ionic bonding (60%), and they are not very soluble at biological pH-values. All these facts open up for possible sensitive extra/intracellular ion measurements. New developments in biosensor design are appearing at a high rate as these devices play increasingly important roles in daily life. In this thesis we have studied calcium ion selectivity of ZnO nanorods sensors using ionophore membrane coatings in two research directions: first, we have adjusted the sensor with sufficient selectivity especially for Ca²⁺, and the second is to have enough sensitivity for measuring Ca²⁺ concentrations in extra and intracellular media. The sensor in this study was used to detect and monitor real changes of Ca²⁺ across human fat cells and frog cells using changes in the electrochemical potential at the interface in the intracellular microenvironment.</p><p>The first part of the thesis presents extracellular studies on calcium ions selectively by using ZnO nanorods grown on the surface of a silver wire (250 μm in diameter) with the aim to produce proto-type electrochemical biosensors. The ZnO nanorods exhibited a Ca²⁺-dependent electrochemical potentiometric behavior in an aqueous solution. The potential difference was found to be linear over a large logarithmic concentration range (1μM to 0.1M) using Ag/AgCl as a reference electrode. To make the sensors selective for calcium ions with sufficient selectivity and stability, plastic membrane coatings containing ionophores were applied. These functionalized ZnO nanorods sensors showed a high sensitivity (26.55 mV/decade) and good stability.</p><p>In the second part, the intracellular determination of Ca²⁺ was performed in two types of cells. For that we have reported functionalized ZnO nanorods grown on the tip of a borosilicate glass capillary (0.7 μm in diameter) used to selectively measure the intracellular free Ca²⁺ concentration in single human adipocytes and frog oocytes. The sensor exhibited a Ca²⁺ linear electrochemical potential over a wide Ca²⁺ concentration range (100 nM to 10 mM). The measurement of the Ca²⁺ concentration using our ZnO nanorods based sensor in living cells were consistent with values of Ca²⁺ concentration reported in the literature.</p><p>The third and final part, presents the calcium ion detection functionalized ZnO nanorods coupled as an extended gate metal oxide semiconductor field effect transistor (MOSFET). The electrochemical response from the interaction between the ZnO nanorods and Ca²⁺ in an aqueous solution was coupled directly to the gate of a MOSFET. The sensor exhibited a linear response within the range of interest from 1 μM to 1 mM. Here we demonstrated that ZnO nanorods grown on a silver wire can be combined with conventional electronic component to produce a sensitive and selective biosensor.</p>

<p>The work in this thesis has been focused on developing surfaces for use in biosensor systems, especially for quartz crystal microbalances. The surfaces were prepared by adsorption of organosulfur molecules onto gold substrates, so called self assembled monolayers (SAMs). By chemical synthesis these thiols can be specifically tailored to provide surfaces with desired properties. The investigated surfaces were all based on thiols terminated with carboxylic acid groups to render hydrophilic surfaces onto which desired proteins can be covalently attached.</p><p>In order to increase the performance of two dimensional carboxyl surfaces, a method for improving the immobilization of proteins to the surface was investigated. The immobilization levels of antibodies were increased by using N-hydroxysulfo-succinimide (sulfo-NHS), instead of N-hydroxy-succinimide (NHS), as stabilizer of the amine reactive intermediate formed by reaction of the carboxyl groups with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The negatively charged sulfo-NHS intermediate promotes the attraction of overall positively charged proteins and enables immobilization also at low pH. In addition, the orientation of the immobilized antibodies was shown to be dependent on the pI of the antibody and to have a profound effect on the subsequent interaction with the antigen.</p><p>The organization of carboxyl terminated SAMs can be poor due to the repellation between the polar terminal groups. By using acidified ethanol as solvent during the assembly step of monolayer formation, the organization in carboxyl terminated alkyl and oligo(ethylene glycol) SAMs was improved. However, the carboxyl groups were found to be converted to ethyl esters, the rate being related to the acid strength. Furthermore, the long-term stability of carboxyl oligo(ethylene glycol) SAMs was investigated. Here, the effect of alkyl chain length on the storage stability was of interest. A short alkyl chain was shown to have a profound negative effect on the storage stability of the SAM, resulting in decomposition and loss of functionality over time compared to when thiols with longer alkyl chains were studied.</p>

<p>The first and main part of this thesis is focused on the design and synthesis of photo-activableand metal chelating alkanethiols. Chelate associated photochemistry (CAP) is a novel conceptof combining two well-known protein (ligand) immobilization strategies to obtain a sensorsurface of covalently bound ligand with defined orientation. This includes nitrilotriacetic acid(NTA) which is used to capture and pre-orientate histidine-tagged proteins to the sensorsurface, followed by UV activation of a neighboring photo-crosslinking agent, benzophenone(BP), to covalently bind the ligand in this favorable orientation. Our results (paper 1) indicatethat up to 55% more activity of the ligand is achieved with the CAP concept compared to theactivity of the randomly oriented ligand (immobilized only by BP). This also yields a surfacethat is more robust compared to if only NTA is used. The photo cross-linking withbenzophenone (BP) adduct is limited to a distance range of 3Å, it is therefore favorable tocapture the ligand before reacting with surface bound BP-adduct. The surface consists of anexcess of ethylene glycols (known for its protein-repellent properties) to prevent non-specificprotein binding, thereby increase the specificity of the sensor surface. With this obtainedsurface chemistry we hope to contribute to the development of large-scale screening systemsand microarrays based on His-tagged labeled biomolecules. This will be used in a number ofapplications such as proteomics-related applications, including drug discovery, the discoveryof lead compounds and characterization of protein-protein interactions.</p><p>The second part of this thesis describes the effect of the synthetic N-(3-oxododecanoyl)-Lhomoserinelactone (30-C12-HSL) on eukaryotic cells. 30-C12-HSL is a natural occurringsignal substance in the bacterium Pseudomonas aeruginosa, and this signal molecule isinvolved in the regulation of bacterial growth. Pseudomonas aeruginosa has been consideredas a common cause of infections in hospitals, especially in patients with compromisedimmune systems. Since the 30-C12-HSL can diffuse freely cross the cell membranes, it isexpected to have influence on the host cell behaviour. Herein, we study how the eukaryoticcells respond to the bacterial signal molecule, 30-C12-HSL. Our results (paper 2) indicatethat 30-C12-HSL disrupt the adherens junctions in human epithelial cells. The disruption iscaused by a hyperphosphorylation of the adherens junction proteins (protein complexbetween epithelial tissues). This suggests the bacterial signals are sensed by that the host cells.</p>

<p>When the cell is under stress arising from oxidation, heat, infection, toxic contamination or any other stressful condition, proteins may unfold and expose residues in their structure that under normal physiological conditions are hidden and shielded from chemical reactions.</p><p>In this licentiate thesis the effects of general oxidative stress on the production of recombinant protein by mammalian cells are considered.</p><p>The work consisted of a broad literary review focused on oxidative stress and cellular response, cross-protection, gene regulation in response to oxidative stress and the relevance of this to pharmaceutical industry. A series of oxidative stressors is described and examined for experimental use. Experimental cultivation and maintenance of several mammalian cell lines was performed and several candidate stressing agents were proven on these cell lines. Menadione was selected as a powerful and consistent stressing agent, and so several experiments were performed where batches of cells were exposed to varying degrees of stress.</p><p>The performance of the cells in regard to production of recombinant protein was then examined by ELISA, showing a strong downregulation of production under stressful conditions. Recombinant protein taken from stressed and control cultures is then isolated, purified and examined with MALDI-TOF spectrometry. Finally mRNA from the cells is isolated and examined by means of microarray. Genes that are significantly regulated are examined, and those genes that may have significance in the area of stress regulation and reaction are listed.</p><p>The results of the study show that mitomycin C exerts oxidative stress on the industrial protein expressing mammalian cell lines tested.</p>