Universiẗat, Diss.--Karlsruhe, 2005.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

A new method is presented for the numerical computation of the generalized eigen- values of real Hamiltonian or symplectic pencils and matrices. The method is strongly backward stable, i.e., it is numerically backward stable and preserves the structure (i.e., Hamiltonian or symplectic). In the case of a Hamiltonian matrix the method is closely related to the square reduced method of Van Loan, but in contrast to that method which may suffer from a loss of accuracy of order sqrt(epsilon), where epsilon is the machine precision, the new method computes the eigenvalues to full possible accuracy.

The extracellular matrix is a multi-functional environment that cells inhabit to form living tissue. To maintain the tissue, cells require constant telemetry with the matrix and respond to a variety of cues by remodeling matrix architecture. In this study the physical and biochemical manipulation of the matrix by resident cells is explored to better understand how these are used to remodel tissue. Cell-populated collagen hydrogels are used as a controllable in vitro tissue model. To directly measure mechanical forces involved with gel contraction, a culture force monitor was designed and built. Measuring dimensional changes together with contractile forces presents a method of separating mechanisms that influence tissue remodeling. Together, these techniques revealed a correlation between contractile force and gel deformation, suggesting a novel method for examining the material properties of the matrix. Limiting matrix metalloproteinase (MMP) activity altered the correlation as predicted, indicating a stiffer matrix. Contractile force was found to be regulated independent of MMP activity. In contrast, contractile force was found to be dependent on α2β1 integrin function. Collagen gel contraction correlated with both α2β1 function and MMP activity, and was significantly enhanced when combined. The results of this study indicate cells have the capacity to use multiple mechanisms for remodeling the extracellular matrix and may alternately use them together or independently to vary the rate of matrix contraction.

No description available.

The CKM matrix element |Vus| can be extracted from the experimental measurement of semileptonic K → π decays and theoretical input for the corresponding vector form factor in QCD. The thesis performs a major improvement of the RBC/UKQCD programme to calculate Kl3 form factor in Nf = 2+1 Lattice QCD using domain wall fermions. We use data from several lattice spacings and dfferent quark masses with lightest pion mass of about 170MeV. Systematic error corresponding to interpolation in the momentum transfer is avoided using partially twisted boundary conditions. Using simulated quark masses near the physical point, reduce the systematic error due to the mass extrapolation. This work explores different kinematic arrangements of pion and Kaon momenta for twisted boundary conditions. This thesis proposes a new ansatz for mass extrapolation. Analysing three sets of simulation data allows for a detailed study of systematic effects leading to the prediction f+kπ (0) = 0:9671(17)(+18-46), where the first error is statistical and the second error systematic. The result allows us to extract the CKM matrix element |Vus| = 0:2237(+13-8) and confirm unitarity of the first row CKM matrix in the Standard Model. Also in this thesis, we discuss porting of Clover Lattice fermion action to Blue Gene-Q architecture. Clover action achieves maximum efficiency of 29.1% for single precision with good weak scaling. Strong scaling shows local volume dependency. In a study of different iterative solvers for Domain Wall Fermion action (DWF), we find that Modified Conjugate Residual(MCR) and Multishift MCR as the most efficient solver compared to CG and GCR. A new probing technique for estimating the diagonal of the inverse Dirac operator in Lattice QCD is introduced and this method is found to be closer to the exact solution than stochastic methods.

No description available.

The chondroitin sulfate proteoglycan (CSPG) aggrecan forms link protein-stabilised complexes with hyaluronan (HA), via its N-terminal G1-domain, that provide cartilage with its load bearing properties. Similar aggregates (potentially containing new members of the link protein family), in which other CSPGs (i.e., versican, brevican and neurocan) substitute for aggrecan, may contribute to the structural integrity of many other tissues including skin and brain. In this thesis, cartilage link protein (cLP) and the G1-domains of aggrecan (AG1) and versican (VG1) were expressed in Drosophila S2 cells, purified to homogeneity and functionally characterised. The recombinant human proteins were found to have properties similar to those described for the native molecules. For example cLP formed dimers, and HA decasaccharides (HA 10-mers) were the minimum size that could compete effectively for their binding to polymeric HA. In addition, gel filtration and protein cross-linking/MALDI-TOF peptide fingerprinting showed that cLP and AG1 interact in the absence or presence of HA. Conversely, cLP and VG1 did not bind directly to each other hi solution yet formed ternary complexes with HA24. N-linked glycosylation of VG1 and AG1 was demonstrated to be unnecessary for either HA binding or the formation of ternary complexes. Additionally, the length of HA required to accommodate two G1-domains was found to be significantly larger for aggrecan than versican, which may reflect differences hi the conformation of HA stabilised on binding these proteins. To further investigate protein-HA interactions, fluorescent HA oligosaccharides were prepared and characterised. HA oligosaccharides labelled with the fluorophore 2-aminobenzoic acid (2AA) from four to 40 residues hi length were purified to homogeneity by ion exchange chromatography using a logarithmic gradient. Molecular weight and purity characterisation of HA oligosaccharides was facilitated by 2AA derivitisation since it enhanced signals in MALDI-TOF mass spectrometry and improves fluorophore-assisted carbohydrate electrophoresis (FACE) analysis by avoiding the inverted parabolic migration characteristic of 2-aminoacridone (AMAC) labelled sugars. The small size and shape of the fluorophore maintains the biological activity of the derivatised oligosaccharides, as demonstrated by their ability to compete for polymeric hyaluronan binding to VG1, AG1 and cLP. An electrophoretic mobility shift assay was used to study VG1 binding to 2AA-labelled HA 8-, 10-, 20-, 30- and 40-mers and although no stable VG1 binding was observed to labelled 8-mers, the equilibrium dissociation constant (100 nM) for VG1 with HA 10-mers was estimated from densitometry analysis of the free oligosaccharide. Interactions involving 2AA labelled HA 20-, 30-, and 40-mers with VG1 also displayed positive cooperativity. Therefore, oligosaccharides labelled with 2-aminobenzoic acid are biologically active and show excellent potential as probes in fluorescence-based assays that investigate protein-carbohydrate interactions.

Thesis (MBA)--Stellenbosch University, 2004. / Page 34 of digitised copy may appear cut off due to the condition of the original hard copy. / ENGLISH ABSTRACT: This report looks at what is important for Matrix Management to be successful in an organisation. After evaluating sixteen articles it was found that eleven elements are critical when implementing Matrix Management. These elements are: • Communication • Strong Leader • Culture • Rewards • Skills in Teams • Clear and Defined Goals • Senior Management Support • Defined Responsibility • Accountability • Procedures and Standards The model that was developed aims to indicate that there are certain fundamentals that an organisation needs to have in place before starting to work in a cross functional manner. These fundamentals are: to understand the goals of the organisation and the team, to develop procedures and standards (these should be communicated on a continuous basis), to define the responsibilities within the organisation and team, and to develop communication channels for internal and external communication. Next the model examines culture, where it differentiates between organisational culture and team culture. Organisation Culture includes innovation, respect for each other, rewarding and accountability. Team culture looks at commitment, cooperation and accountabilities. Then the model examines the three role players namely the senior management and their support, strong team leadership and the team members that are empowered and correctly skilled. All of these are interlinked through communication. It appears that little has changed over the past twenty years with regards to the fundamentals necessary to be successful. It is only the people and the organisations themselves that have changed. / AFRIKAANSE OPSOMMING: Hierdie verslag kyk na wat nodig is vir Matriks Bestuur om suksesvol te wees in 'n organisasie. Na die ontleding van sestien artikels is gevind dat elf elemente baie belangrik is tydens die implementering van Matriks Bestuur. Hierdie elemente is: • Kommunikasie • Sterk Leier • Kultuur • Vergoeding • Vaardighede in Spanne • Duidelike Doelwitte • Bemagtigde Lede • Senior Bestuur Ondersteuning • Gedefinieerde Verantwoordelikheid • Toerekenbaarheid • Prosedures en Standaardes Die model wat ontwikkel is probeer om uit te wys dat daar sekere fundamentele elemente is wat 'n organisasie in plek moet he voordat daar kruis-funksioneel begin werk word. Die fundamentele elemente is: verstaan die doelwitte van die organisasie en span, om prosedures en standaarde te ontwikkel (moet op 'n gereelde basis gekommunikeer word), om die verantwoordelikhede binne die organisasie en span te definieer, en om kommunikasie kanale vir interne en eksterne kommunikasie te ontwikkel. Volgende kyk die model na kultuur waar dit onderskei tussen organisasiekuituur en span-kultuur. Innovasie, respek vir mekaar, vergoeding en toerekenbaarheid val onder Organisasie kultuur en verbondenheid, samewerking en toerekenbaarheid val onder Span kultuur. Volgende kyk die model na die drie rolspelers naamlik senior bestuur en hulondersteuning, sterk spanleierskap en spanlede wat vaardig en volmagtig is. AI hierdie word deur kommunikasie verbind. Dit blyk dat nie veel verander het gedurende die laaste twintig jaar ten opsigte van die fundamentele elemente wat nodig is omsuksesvol te wees nie. Dit is slegs die mense en organisasies wat verander het.

published_or_final_version / Zoology / Doctoral / Doctor of Philosophy