Metal-dithiocarbamate complexes find wide-ranging applications in nanomaterial and metalseparation science, and have potential use as chemotherapeutic, pesticides, and as additives tolubricants. A highly versatile dialkyldithiocarbamate (R2NCS2–) ligand can form stablecomplexes with all the transition elements and also the majority of main group, lanthanide andactinide elements. Here we present structural investigations of the molecular and electronicstructures of dialkyldithiocarbamate complexes with yttrium(III), lanthanum(III), andbismuth(III) of molecular formula [Y{S2CN(C2H5)2}3PHEN], [La{S2CN(C2H5)2}3PHEN], and[Bi2{S2CN-n(C4H9)2}6] (where PHEN=1,10-Phenanthroline) . The experimental solid-state 13Cand 15N cross polarization magic-angle-spinning (CP-MAS) NMR results are reported for allthese three complexes. We also report new single-crystal X-ray structures of heterolepticyttrium, lanthanum, and homoleptic bismuth dialkyldithiocarbamate complexes. Thecomparative analysis of powder XRD patterns and solid-state 13C and 15N CP-MAS spectra ofpolycrystalline yttrium(III) and lanthanum(III) diethyldithiocarbamato-phenanthrolinecomplexes shows the presence of significant structural differences. The diethyldithiocarbamatophenanthrolinecomplex of yttrium has a very similar structural type to a previously reported Xraydiffraction structure for [Nd{S2CN(C2H5)2}3PHEN] whereas, the crystal structure of[La{S2CN(C2H5)2}3PHEN] is considerably more complex. Our NMR and single-crystal X-raydiffraction results suggested polymorphism for bismuth di-n-butyldithiocarbamate complex.Finally, the experimental NMR results are complemented by chemical shifts obtained usingquantum chemical methods and verified the spectral assignments. Overall, our workdemonstrates how different experimental and theoretical methods can be combined that canafford insights into the solid-state structure and bonding environments of metal complexes.

<p>The behavior of block copolymer and protein films at interfaces is of central importance to their function in many application areas. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers function e.g. as emulsifiers and in coatings in oral, parenteral, and topical pharmaceutical formulations and are also widely used for cleaning purposes. The globular protein β-lactoglobulin is the most abundant whey protein and it is used within the food industry as a component of many common foods. To understand the interfacial behavior of block copolymers and proteins in such applications one has to study molecular processes like adsorption, the responses to shear and dilatational deformation of the interface (i.e. surface rheology), conformational changes of the molecules, and forces that are generated between interfacial layers. Such investigations form the focus of the work presented in this thesis. </p><p>Thin film measurements with a series of block copolymers composed of poly(ethylene oxide) and poly(butylene oxide) revealed that the thickness of foam films (air-aqueous solution-air) is determined by electrostatic and steric repulsion. The range of the steric repulsion is directly dependent on the size of the polymer, in particular the length of the poly(ethylene oxide) chains. Block copolymers attached to the air-water interface change their conformation with increasing surface concentration. The study of the dilatational modulus as a function of the surface pressure of spread and adsorbed block copolymer layers showed that the block copolymers pass from a two-dimensional conformation to a three-dimensional extended structure as the available area per molecule decreases. Relaxation processes occur mainly by a redistribution of segments within the surface layer. Mixing of the hydrophobic poly(propylene oxide) segments in a sublayer of poly(ethylene oxide) and water was proposed to occur at high surface concentration of the polymer. Conformational changes (partial denaturation) of globular proteins upon adsorption at the air-water interface leads to the formation of highly viscoelastic networks, which play an important role for the stabilization of foams and emulsions. Mixed layers, formed by competitive adsorption of β-lactoglobulin and block copolymers, were also investigated. On increasing the concentration of block copolymer, the viscoelasticity of the mixed protein/block copolymer layer gradually decreased. The polymer was able to displace the protein from the interface. The drainage rate of thin liquid films was also enhanced by the presence of block copolymer. Whether or not the incorporation of the polymer in the β-lactoglobulin layer has a detrimental effect on foam stability depends on the ability of the polymer to generate long-range steric repulsion across the foam films. For pure block copolymer systems, correlations between foam stability and the thickness of interfacial layers, in the steric regime, were found. The results obtained can be utilized for increasing the understanding of the mechanisms for foam stabilization in both model and industrial systems. </p>

The behavior of block copolymer and protein films at interfaces is of central importance to their function in many application areas. Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers function e.g. as emulsifiers and in coatings in oral, parenteral, and topical pharmaceutical formulations and are also widely used for cleaning purposes. The globular protein β-lactoglobulin is the most abundant whey protein and it is used within the food industry as a component of many common foods. To understand the interfacial behavior of block copolymers and proteins in such applications one has to study molecular processes like adsorption, the responses to shear and dilatational deformation of the interface (i.e. surface rheology), conformational changes of the molecules, and forces that are generated between interfacial layers. Such investigations form the focus of the work presented in this thesis. Thin film measurements with a series of block copolymers composed of poly(ethylene oxide) and poly(butylene oxide) revealed that the thickness of foam films (air-aqueous solution-air) is determined by electrostatic and steric repulsion. The range of the steric repulsion is directly dependent on the size of the polymer, in particular the length of the poly(ethylene oxide) chains. Block copolymers attached to the air-water interface change their conformation with increasing surface concentration. The study of the dilatational modulus as a function of the surface pressure of spread and adsorbed block copolymer layers showed that the block copolymers pass from a two-dimensional conformation to a three-dimensional extended structure as the available area per molecule decreases. Relaxation processes occur mainly by a redistribution of segments within the surface layer. Mixing of the hydrophobic poly(propylene oxide) segments in a sublayer of poly(ethylene oxide) and water was proposed to occur at high surface concentration of the polymer. Conformational changes (partial denaturation) of globular proteins upon adsorption at the air-water interface leads to the formation of highly viscoelastic networks, which play an important role for the stabilization of foams and emulsions. Mixed layers, formed by competitive adsorption of β-lactoglobulin and block copolymers, were also investigated. On increasing the concentration of block copolymer, the viscoelasticity of the mixed protein/block copolymer layer gradually decreased. The polymer was able to displace the protein from the interface. The drainage rate of thin liquid films was also enhanced by the presence of block copolymer. Whether or not the incorporation of the polymer in the β-lactoglobulin layer has a detrimental effect on foam stability depends on the ability of the polymer to generate long-range steric repulsion across the foam films. For pure block copolymer systems, correlations between foam stability and the thickness of interfacial layers, in the steric regime, were found. The results obtained can be utilized for increasing the understanding of the mechanisms for foam stabilization in both model and industrial systems. / QC 20101011

Fabrication of miniaturized devices is usually time-consuming, costly, and the materials commonly used limit the structures that are possible to create. The techniques most often used to make microsystems involve multiple steps, where each step takes considerable time, and if only a few systems are to be made, the price per device becomes excessive. This thesis describes how a simple syringebased 3D-printer, in combination with an appropriate choice of materials, can reduce the delay between design and prototype and simplify fabrication of microsystems. This thesis suggest two types of materials that we propose be used in combination with 3D-printing to further develop microsystems for biology and biochemistry. Analytical applications in biology and biochemistry often contain electrodes, such as in gel electrophoresis. Faradaic (electrochemical) reactions have to occur at the metal electrodes to allow electron-to-ion transduction through an electrolyte-based system to drive a current when a potential is applied to the electrodes in an electrolyte-based system. These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic when miniaturizing devices and analytical systems. An alternative to metal electrodes can be electrochemicallyactive conducting polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT), which can be used to reduce electrolysis when driving a current through water-based systems. Paper 1 describes gel electrophoresis where the platinum electrodes were replaced with the conductive polymer PEDOT, without affecting the separation. Manufacturing and prototyping of microsystems can be simplified by using 3Dprinting in combination with a sacrificial material. A sacrificial template material can further simplify bottom-up manufacturing of more complicated forms such as protruding and overhanging structures. We showed in paper 2 that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D-printable sacrificial template material. PEG2000 with between 20 wt% and 30 wt% ethylene carbonate or propylene carbonate has properties advantageous for 3D-printing, such as shear-thinning rheology, mechanical and chemical stability, and easy dissolution in water. / <p>In the printed version the thesis number <strong>1720</strong> on the cover is incorrect. The correct thesis number is <strong>1724</strong> which is corrected in the electronic version.</p>

Mn+1AXn (MAX) phases are nanolaminated compounds based on a transition metal (M), a group A element (A), and carbon or/and nitrogen (X), which exhibit a unique combination of ceramic and metallic properties. Mo-based MAX phases are among the least studied, despite indication of superconducting properties and high potential for fabrication of the grapheneanalogous 2D counterpart, Mo2C MXene. Furthermore, incorporation of Mn atoms in these MAX phases may induce a magnetic response. In this work, I have performed theoretical calculations focused on evaluation of phase stability of the Mon+1GaCn MAX phases, and have synthesized the predicted stable Mo2GaC in thin film form using magnetron sputtering. Close to phase pure epitaxial films were grown at ~590 ºC, and electrical resistivity measurements using a four point probe technique suggest a superconducting behavior with a critical temperature of ~7 K. The A-layer in the MAX phase can be selectively etched using different types of acids, leading to exfoliation of the MX-layers and realization of MXenes. After synthesis of the MAX phase related material Mo2Ga2C, the previously non-explored Mo2C MXene could be fabricated from etching Mo2Ga2C thin films in 50% hydrofluoric acid at a temperature of ~50 ºC for a duration of ~3 h. Motivated by the realization of laminated Mo-based materials in 3D as well as 2D, I set out to explore the magnetic properties resulting from Mn-alloying of the non-magnetic Mo2GaC phase. For that purpose, (Mo,Mn)2GaC was synthesized using a DC magnetron sputtering system with Ga and C as elemental targets and a 1:1 atomic ratio Mo:Mn compound target. Heteroepitaxial films on MgO(111) substrates were grown at ~530 ºC, as confirmed by X-ray diffraction. Compositional analysis using energy dispersive X-ray spectroscopy showed a 2:1 ratio of the M and A elements and a 1:1 ratio for the Mo and Mn atoms in the film. Vibrating sample magnetometry was utilized in order to measure the magnetic behavior of the films, showing a magnetic response up to at least 300 K, and with a coercive field of 0.06 T, which is the highest reported for any MAX phase to date. / <p>The series name <em>Linköping Studies in Science and Technology Licentiate Thesis</em> is incorrect. The correct series name is <em>Linköping Studies in Science and Technology Thesis</em>.</p>

Rapporten avser att visa på vikten av fysisk aktivitet som en faktor som påverkar skolresultat.

The recent emergence of earth-abundant iron(III)-photosensitizers with N-heterocyclic carbene ligands, exhibiting nanosecond ligand-to-metal charge-transfer states with suitable redox potentials to activate a broad range of substances, offers the possibility to convert sunlight into chemical substances, such as fuels or pharmaceuticals, in an environmentally friendly way. These complexes, however, often suffer from low yields of charge-separated products escaping the solvent cage, making such applications inherently inefficient. This behavior has been attributed to the fact that back electron transfer is a spin-allowed process in these systems, as both the charge separated as well as the ground state are doublet states. The back electron transfer may hence be slowed down by a heavy atom-induced spin-orbit coupling to a quartet charge-separated state. This hypothesis has recently been postulated to explain a thirty-fold increase in cage escape yield for the reductive excited state quenching of [FeIII(pthmeimb)2]+ (phtmeimb = phenyl [tris(3-methyl-imidaz-olin-2-ylidene)]borate) by substituted alkyl/aryl amines in dichloromethane compared to the same reactions in acetonitrile. The work conducted in this thesis aimed to shine light onto this spin-orbit coupling effect by either introducing heavy atoms in the quencher or the solvent and quantifying their influence on the cage escape yields for both reductive quenching using [FeIII(pthmeimb)2]+ and [FeIII(btz)3]3+ (btz = 4,4’-bis(1,2,3-triazol-5-ylidene), as well as for previously unaddressed oxidative quenching using [FeIII(pthmeimb)2]+ by use of steady-state as well as time-resolved spectroscopic experiments. The results in this thesis highlighted that heavy-atom induced spin-orbit coupling, if present, may only have a small influence on the cage escape yield and that this effect is unlikely to be the sole contributor of the previously observed increase in dichloromethane.

Subcutaneous administration of biological drugs has become highly attractive as it offers the possibility for patient self-administration. Coacervates as a subcutaneous drug delivery system provide a way to decrease injection volumes thereby reducing the risk of injection site pain. The aim with this thesis was to investigate possible coacervation between polyelectrolytes and peptide drugs under various physicochemical conditions. In this project, hyaluronic acid (HA) and carboxymethylcellulose (CMC) and their ability to coacervate with polymyxin B (PB) and vancomycin (VA) was studied. Furthermore, the release of these peptide drugs from the formulations into a release medium mimicking the subcutaneous environment was studied using UV spectroscopy. Studies showed successful coacervation between VA-CMC, PB-CMC and PB-HA. VA-CMC and PB-CMC coacervates were formed at higher peptide-polyelectrolyte charge ratios and lower ionic strengths at pH 7. The increase in charge ratio seemed to eliminate steric effects caused by the polyelectrolyte chains that most likely hindered coacervation. Furthermore, PB-CMC and PB-HA formed gel-like coacervates in the pH range of 11.73-11.84 at 1:1 charge ratio and ionic strengths 0-70mM. At such high pH values, the obtained formulations were most likely a result of PB-PB aggregation or charge regulation. From drug release studies one could conclude that VA-CMC exhibits direct release followed by a slower prolonged release profile. PB-CMC coacervates, liquid and gel, showed a sustained release profile while the PB-HA gel formulation resulted in direct release. Unfortunately, due to limitations with the experimental release rate set-up, the conclusions drawn can not be considered 100% reliable.

No description available.

<p>Lévy flights and Lévy walks are two mathematical models used to describe anomalous diffusion(i.e. those having mean square displacements nonlinearly related to time (as opposed to Brownian motion)). Lévy flights follow probability distributions p(|<strong>r</strong>|) yielding infinite mean square displacements since some rare steps are very long. Lévy walks, however, have coupled space-time probability distributions penalising very long steps. Both Lévy flights and Lévy walks are dominated by a few long steps, but most steps are much, much smaller. The semi-experimental part ofthis work dealt with how fluorescent probes moved in systems of cationic starch and latex/solutions of dodecyl trimethyl ammonium bromide, respectively. Visually, no Lévy walks couldbe detected. However, mathematical regression suggested enhanced diffusion and subdiffusion. Moreover, time-dependent diffusion coefficients were calculated. Also examined was how Microsoft Excel could be used to generate normal diffusion as well as anomalous diffusion.</p> / <p>Lévyflygningar och Lévypromenader är matematiska modeller som används för att beskriva anomal diffusion (i.e. dessa då medelvärdet av kvadratförflyttningarna är icke-linjärt relaterat tilltiden (till skillnad från Brownsk rörelse)). Lévyflygningar följer sannolikhetsfördelningar p(|<strong>r</strong>|)som ger oändliga medelkvadratförflyttningar eftersom vissa steg är väldigt långa. Lévypromenader,å andra sidan, har kopplade rum-tid-sannolikhetsfördelningar som kraftigt reducerar demycket långa stegen. Både Lévyflygningar och -promenader domineras av ett fåtal långa steg ävenom de flesta steg är mycket, mycket mindre. Den semiexperimentella delen av detta arbetestuderade hur fluorescerande prober rör sig i katjonisk stärkelse respektive latex/lösningar avdodecyltrimetylammoniumbromid. Inga Lévypromenader kunde ses. Emellertid taladematematisk regression för att superdiffusion och subdiffusion förelåg. Tidsberoende diffusionskoefficienter beräknades också. I detta arbete undersöktes även hur Microsoft Excel kan användas för att generera både normal och anomal diffusion.</p>