A associação de adubos verdes a fontes minerais de N para as culturas está tornando-se uma opção promissora de manejo da fertilização nitrogenada, com o objetivo de recuperar a fertilidade de solo, aumentar a matéria orgânica do solo, reduzir as perdas de N mineral de fontes prontamente disponíveis, e no caso das leguminosas incorporarem nitrogênio ao solo proveniente da fixação biológica. Os objetivos deste trabalho foram: (1) avaliar o aproveitamento do nitrogênio da crotalária, do milheto e da uréia pelo arroz e o efeito residual no feijoeiro cultivado em sucessão, (2) avaliar a contribuição do N das raízes e da parte aérea desses adubos verdes para o arroz e o feijoeiro, e (3) quantificar o N na planta proveniente dos adubos verdes em relação à época de aplicação da uréia (semeadura e cobertura). Foram desenvolvidos experimentos com Latossolo Vermelho distroférrico típico em casa de vegetação no CENA/USP em três fases: (a) marcação isotópica dos adubos verdes com 15N realizada com (NH4)2SO4 enriquecido em 10 e 5% de átomos de 15N para a crotalária e milheto, respectivamente, (b) cultivo de arroz em vasos de 4 kg de TFSA com delineamento experimental inteiramente casualizado com 12 tratamentos e três repetições, dispostos em esquema fatorial 3 x 4, correspondendo a combinação de crotalária, milheto e sem adição fonte orgânica de N com quatro doses de 15N-uréia (0; 28,6; 57,2; 85,8 mg kg-1 de N ), e (c) cultivo de feijão nos mesmos vasos após o cultivo de arroz. A produtividade de grãos de arroz foi influenciada positivamente pela utilização de crotalária quando comparada ao milheto e ao tratamento sem adubo verde, com maior efeito a medida que se aumentou a dose de N mineral. O aproveitamento do N da crotalária (18,9%) foi mais de duas vezes superior ao do milheto (7,8%). As doses de uréia, nos tratamentos com ou sem uso adubo verde, não influenciaram o aproveitamento de N do fertilizante pela planta de arroz (palha+grão), sendo a media geral de aproveitamento de N-uréia de 53,76%. O aproveitamento do N das raízes dos adubos verdes foi de 14,1%, enquanto da parte aérea foi de 16,8%. Com o uso de crotalária, observou-se maior aproveitamento de N-uréia aplicado na semeadura (61,7%) em relação à cobertura (47,1%), mas esse efeito não foi observado para o milheto e sem adição de adubo verde. O aproveitamento do N residual dos adubos verdes pelo feijão foi de 3,56% para o N da crotalária e de 3,43% para o N de milheto, e superior ao do N do fertilizante (2,63%). / The association of green manures and mineral N sources is becoming a promising option for nitrogen fertilizer management, with the objective of recovering the soil fertility, increase of soil organic matter, reduce the loss of mineral N from the readily available sources, and in the case of legume incorporate biologically fixed N to the soil. The objectives of this research were to: (1) evaluate the utilization of N by the rice crop from crotalaria (sunnhemp), millet and urea and its residual effect on bean crop (Phaseolus vulgaris L.) grown in succession; (2) evaluate the contribution of N from the roots and above ground part of these green manures to rice and bean crops, and (3) quantity the N in the plant derived from the green manures in relation to the urea application time (at seeding and topdressing). Experiments were carried out with typic dystrophic Red Latosol (oxisol) in green house at CENA/ USP, in three phases: (a) green manures labeling with 15N, using (NH4)2SO4 enriched with 10 and 5% 15N, for crotalaria and millet, respectively; (b) rice growth in pots containing 4 kg of air dried soil, in completely randomized design with 12 treatments and three replicates, arranged in a 3 x 4 factorial scheme, corresponding to combination of crotalaria, millet and without addition of organic N, with four rates of urea-15N (0; 28.6; 57.2; 85.8 mg N Kg-1), and (c) bean plant growth after rice cultivations. The rice grain productivity was affected positively by the crotalaria when compared to millet and treatment without green manure, with greater effect with increasing mineral N rate. The crotalaria N utilization (18.9%) by the rice plants was more than two times higher than from the millet (7.8%). The urea rates, in the treatments with or without green manure, did not affect the utilization by the rice plants (grains + husk) of N form the fertilizer (53.76% in average). The utilization of green manure roots N by the rice plants was 14.1%, while of above ground parts was 16.8%. With crotalaria, higher utilization of N occurred from urea applied at seeding (61.7%) compared to the top dressed application (47.1%), but this effect was not observed for millet and without addition of green manure. The utilization of green manures residual N by the bean crop was only 3.56% from crotalaria and 3.43% from millet, which were higher than from fertilizer N (2.63%).

La spondyloarthrite (SpA) est une pathologie rhumatologique caractérisée notamment par une inflammation et par des ossifications excessives se formant au niveau des enthèses. Il s’agit de zones de fortes contraintes mécaniques où les tendons et ligaments sont ancrés dans l’os via une zone fibrocartilagineuse. La sphingosine 1-phosphate (S1P) est un lipide bioactif qui joue un rôle important à la fois dans le remodelage osseux et la réponse inflammatoire. Notre objectif était donc d’explorer le rôle de la S1P dans l’ossification excessive de la SpA. Nous avons observé que les taux sériques de S1P des patients atteints de SpA sont significativement supérieurs à ceux de donneurs contrôles. Nous avons utilisé comme modèle des cultures primaires murines d’ostéoblastes, de chondrocytes et de ténocytes et des cultures organotypiques d’enthèse de souris. Nous avons observé que les enzymes de synthèse de la S1P, les sphingosine kinases 1 et 2, contribuent à la minéralisation des ostéoblastes et des chondrocytes. L’effet pro-minéralisant de la S1P est partiellement médié par deux de ses récepteurs (S1P1 et S1P3). De plus, la production de S1P est stimulée suite à un étirement cyclique dans les ostéoblastes et les chondrocytes, et après un traitement avec les cytokines TNF-α et IL-17 dans les chondrocytes. Finalement, l’inhibition générale du métabolisme de la S1P par le Fingolimod conduit à une diminution de la minéralisation dans les ostéoblastes et encore davantage dans les chondrocytes. Ces résultats suggèrent que le métabolisme de la S1P participe à l’ossification excessive de la SpA. Des études in vivo sont maintenant nécessaires pour valider cette possibilité / Spondyloarthritis (SpA) is a rheumatic disease characterized in particular by enthesis ectopic ossification and inflammation. Enthesis is a zone of concentration of mechanical stresses where ligaments and tendons attach to bone through fibrocartilaginous connections. Sphingosine 1-phosphate (S1P) is a bioactive lipid that plays an important role in both bone remodelling and in inflammatory response. Our aim was to explore the role of S1P in SpA excessive ossification. We observed that serum S1P concentrations in SpA patients are significantly higher compared to control donors. We used primary mouse osteoblasts, chondrocytes and tenocytes as cellular models and organotypic cultures of mice enthesis. We observed that S1P synthetizing enzymes, sphingosine kinases 1 and 2, stimulate osteoblasts’ and chondrocytes’ mineralizing process. S1P pro-mineralizing effect was partially mediated by two of the S1P receptors (S1P1 and S1P3). Moreover, S1P production was enhanced by cyclic strain in osteoblasts and chondrocytes and by pro-inflammatory cytokines (TNF-α and IL-17) in chondrocytes. Finally, the inhibition of S1P metabolic pathway by Fingolimod reduced the mineralization in cultured osteoblasts and even more in chondrocytes. These results suggest that S1P metabolism participates in SpA excessive ossification. In vivo studies are now needed to validate this possibility

During the period of October 1974 to August 1976, a study was conducted to measure the effects of surface soil removal on plant production, plant transpiration rates, nitrate nitrogen mineralization rates, and selected hydrologic parameters (infiltration rates, potential sediment production, and chemical quality of runoff water). The treatments were incremental 7.6 centimeter soil layers to a depth of 30.5 centimeters. Plant production and transpiration ratios (or water use efficiencies) were measured in greenhouse studies using Agrogyron desertorum grown in the incremental 7.6 centimeter soil layers from five study sites throughout the state of Utah, (Blanding, Brush Creek, Milford, Huntington, and Dove Creek). Significant decreases in plant production and increases in transpiration ratios were measured for all sites at incremental depths beyond 7.6 centimeters. These changes in plant production and transpiration ratios were found to be linearly related to the nitrate nitrogen content of the soils as determined at the time the soils were collected for use in the greenhouse. Nitrogen mineralization rates for a 6 week period were measured under field conditions at Milford and Blanding for each of the 7.6 centimeter incremental soil layers. Nitrate nitrogen mineralization was linearly correlated to the organic carbon content of the soil. Decreased mineralization rates as measured in the field at both study sites were reflected in significant increases in plant water requirements and also decreases in production as measured in greenhouse studies. Hydrologic parameters were measured at each 7.6 centimeter incremental soil depth using a Rocky Mountain infiltrometer. With one exception, significant differences in infiltration capacities among treatment depths did not occur during either 1975 or 1976 at either the Blanding or Milford site. At the Blanding site a significant decrease in the infiltration capacity occurred beyond the 22.9 centimeter depth due to a hardpan development. A significant change in infiltration capacities was noted between the 1975 and 1976 field seasons as pooled over both treatment depths and study sites. There were no significant differences in potential sediment production between sites or among treatment depths within a site. In terms of runoff water quality, a significant change in phosphorus was observed only at the Blanding site between the 1975 and 1976 field seasons. Significant differences in potassium concentrations were found to exist between sites and among soil depths.

Les vésicules matricielles sont des organites extracellulaires impliques dans les processus de minéralisation. Nous avons détermine le mode d’action du strontium, ion contenu dans le principe actif d’un médicament antiostéoporotique sur les vésicules matricielles. Nous avons montre que le strontium agit en fonction de la concentration aussi bien sur la formation de l’hydroxyapatite que sur les activités phosphomonoéstérase et phosphodiestérase de la phosphatase alcaline tissu non spécifique. Pour des faibles concentrations (comprises entre 25 et 100^M), le strontium augmente l’activité phosphodiestérase et inhibe partiellement l’activité phosphomonoestérase. La balance entre la production de PPi, inhibiteur de la minéralisation et la production de Pi, essentiel a la formation d’hydroxyapatité pourrait être affectée par le strontium. / The matrix vesicles are extracellular organelles implicated in the process of mineralization.We determined the mode of action of strontium, ion contained in the active principle of an antiosteoporotic drug on the matrix vesicles. We showed that the action of strontium is concentration dependent on the hydroxyapatite formation and on phosphomonoesterase and phosphodiesterase activities of the tissue non specific alkaline phosphatase. At low concentration (between 25 and 100^M), strontium increased phosphodiesterase activity and inhibited partly phosphomonoesterase activity. The balance between the production of PPi, inhibitor of mineralization and the production of Pi, essential in the formation of hydroxyapatite could be affected by the strontium.

Phosphorus (P) is an essential plant nutrient that may limit plant growth and agricultural productivity if not available for crop plant uptake in sufficient quantities at the time required. Many Australian soils are deficient in available P, despite a long history of P fertilizer application, and this is due to fertilizer P rapidly becoming unavailable largely through biochemical fixation. The resulting low P fertilizer efficiency, coupled with rapidly rising cost of fertilizers, has increased interest in biological cycling of P from sources such as crop residues. However, to date, much of the Australian research has focussed on soils with relatively high organic matter content (> 2%) and relatively heavy texture i.e. medium to high clay content. Furthermore, although there is information on pasture residue decomposition and P release for sandy soils with low organic matter in Australia, a recent shift to continuous cropping systems means that information for a range of crop residues is required but is not currently available. Therefore the aims of the work described in this thesis were to (i) increase the efficiency of P use when crop residue P are applied to crops and (ii) determine the effect of crop residue biochemical quality on decomposition rates, soil P dynamics and plant P uptake in light textured sandy soils with low organic matter which are typical of a large proportion of the southern Australian wheat growing area. A further aim was to investigate the effects of combined additions of plant residue and P fertilizer on P cycling in these soils, a scenario highly relevant to farming systems. A series of soil incubation and plant growth experiments were undertaken to characterize P dynamics in soil following addition of a wide range of crop residues (total 15) collected from agricultural sites throughout South Australia. The residues, differing in age and biochemical quality, were young shoots of canola, lupin, pea, lucerne and lentil; mature shoot residues of canola, lupin, pea and wheat and mature root residues of wheat, canola and lupin. The concentration of total and water soluble P, C, and N in the residues was measured using standard wet chemical analyses and the carbon chemistry was determined by NMR spectroscopy. Decomposition of crop residues was continuously monitored over a period of up to 140 days by measuring soil respiration. Available P and microbial biomass P and C were also assessed at different times during the incubations. The total P in residues ranged from 0.16% to 0.32% and 0.05% to 0.08% in young and mature shoots, respectively. Water-soluble P was related to residue total P and ranged from 29% to 81% and 13% to 29% of total P in young and mature shoots, respectively. The C: P ratio ranged from 133: 1 to 253: 1 and 504: 1 to 858: 1 in young and mature shoots, respectively. Phosphorus availability and microbial P uptake differed between soils amended with crop residues and soluble P fertilizer as triple super phosphate (TSP). Soil respiration rates were significantly higher in soils amended with crop residues than in the soils amended with TSP or the unamended control in the first 58 days of incubation. In an experiment in which residues and TSP were added at a rate of 10 mg P kg⁻¹, available P was greater for TSP than residue-amended soil, whereas microbial P showed the opposite trend. Respiration rate and microbial P were positively correlated with C addition rate, which was highest in mature wheat residue because it had the lowest P concentration. In order to assess when P released from the residues is available for plants, wheat was grown over three consecutive crop periods with each period lasting for 4 weeks. Young residues with high content of water soluble P, C, N and amide and low lignin and phenolic content decomposed faster than mature residues. The C type and amount added with residues controlled the dynamics of P availability. Surprisingly, canola mature root increased available P and plant growth as much as young shoot residues while root residues of wheat and lupin resulted in P immobilization and low plant growth. Compared to canola young shoot, canola mature root has a higher total P concentration and a lower C: P ratio. Plant P uptake was positively correlated with residue total and water-soluble P content and negatively correlated with residue C: P and C: N ratio and amount of C added with the residues. In another experiment where residue was added at 2.5 g C kg⁻¹ soil and compared with TSP (4 and 10 mg P kg⁻¹ soil), available P and plant P uptake decreased in the following order: TSP-10P > canola root ≥ young shoot ≥ TSP-4P > control > mature shoot. Microbial P was greater with residue addition than with TSP and in the control. Residues with low total P and high C: P ratio resulted in P immobilisation in the microbial biomass. Therefore, residues with high total P and low C: P ratio can be an important source of P for plants. Net P immobilisation of mature wheat residues (0.07% P) was significantly reduced by combining wheat residue (C: P ratio 615: 1) with TSP leading to a C: P ratio of 155: 1 to 310: 1. Furthermore, the combination of wheat residue with TSP increased available P in residue and TSP-amended soils by 3.0 mg P kg⁻¹ soil, which was shown to be sufficient to support wheat growth in the early stages of development in the other experiments. Although water-soluble P fertilizers provide plants with immediately available P, a large proportion becomes unavailable over time. Addition of low C: P residues on the other hand, may not result in high amounts of immediately available P, but the P supply is more sustained due to P release from decomposing residues and turnover of microbial biomass P. Phosphorus immobilization after addition of residues which have high C: P ratio (615: 1) may be offset when residue is applied together with inorganic P fertilizer if the resulting C: P ratio is 300: 1 or less. Overall, this study has highlighted the potential role that crop residues, either alone or in combination with inorganic P, can play in increasing P availability in the light textured, low organic matter, P-limited soils typical of many southern Australian farming systems. The results provide important quantitative information on the potential of a wide range of crop residues to supply wheat with P, and how additions of inorganic P interact with residue decomposition and influence available P supply. This quantitative information will be valuable for the construction or validation of mechanistic models of residue decomposition relevant to low organc matter light textured soils in farming systems of southern Australia, and will ultimately assist in the development of economic management strategies for minimizing P fertilizer inputs and maximizing the benefits of biological cycling of P. / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2009

<p>The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing the frequency range into the LW radio band. Airborne and ground VLF data are interpreted and correlated with RMT measurements made on the ground to better understand the resolution power of VLF data. To aid in this understanding single and multifrequency VLF and RMT responses for some typical resistivity structures are analyzed. An analytic model is presented for obtaining unique transfer functions from measurements of the electromagnetic components on board an air-plane or on the ground. Examples of 2D inversion of ground and airborne VLF profiles in Sweden are shown to demonstrate the quantitative interpretation of VLF data in terms of both lateral and depth changes of the resistivity in the uppermost crust.</p><p>Geothermal resources are ideal targets for Electromagnetic (EM) methods since they produce strong variations in underground electrical resistivity. Modelling of Magnetotelluric (MT) data in SW Iceland indicates an alteration zone beneath the surface, where there are no obvious geothermal manifestations, in between Hengill and Brennisteinsfjoll geothermal systems. It suggests that a hydrothermal fluid circulation exists at depth. It also proves that the MT method, with its ability to map deep conductive features can play a valuable role in the reconnaissance of deep geothermal systems in active rift regimes such as in Iceland.</p><p>A damped nonlinear least-squares inversion approach is employed to invert Controlled Source Tensor MT (CSTMT) data for azimuthal anisotropy in a 1D layered earth. Impedance and tipper data are inverted jointly. The effects of near-surface inhomogeneities are parameterized in addition to each layer parameter(s). Application of the inversion algorithm to both synthetic and field data shows that the CSTMT method can be used to detect azimuthal anisotropy under realistic conditions with near surface lateral heterogeneities.</p>

Cell adhesion to the extracellular matrix through cell-surface integrin receptors is essential to development, wound healing, and tissue remodeling and therefore represents a central theme in the design of bioactive surfaces that successfully interface with the body. This is especially significant in the areas of integrative implant coatings since adhesion triggers signals that regulate cell cycle progression and differentiation in multiple cellular systems. The interactions of osteoblasts with their surrounding extracellular matrix are essential for skeletal development and homeostasis and the maintenance of the mature osteoblastic phenotype. Our objective was to engineer integrin-specific bioactive surfaces that support osteoblastic differentiation and promote osseointegration by mimicking these interactions. We target two specific integrins essential to osteoblast differentiation the type I collagen receptor alpha2beta1 and the fibronectin receptor alpha5beta1. The central hypothesis of this project was that the controlled presentation of type I collagen and fibronectin binding domains onto well-defined substrates would result in integrin-specific bioadhesive surfaces that support osteoblastic differentiation, matrix mineralization, and osseointegration. We have demonstrated that these biomimetic peptides enhance bone formation and mechanical osseointegration on titanium implants in a rat tibia cortical bone model. We have also shown that the presentation of multiple integrin-binding ligands synergize to enhance intracellular signaling and proliferation. Finally, we demonstrate the advantage of the short biomimetic peptides over the native ECM proteins. This research is significant because it addresses current orthopaedic implant limitations by specifically targeting cellular responses that are critical to osteoblastic differentiation and bone formation. This biomolecular approach provides a versatile and robust strategy for developing bioactive surfaces that enhance bone repair and osseointegration of orthopaedic implants.

Samli Fe-oxide (+Cu&plusmn / Au) deposit is hosted by Samli pluton and rocks of Karakaya Complex in western Anatolia. The pluton consists of both mafic and felsic phases showing magma mixing textures. 40Ar/39Ar geochronology yielded an age range of 23.2&plusmn / 0.5 to 22.42&plusmn / 0.11 Ma for the Samli pluton, overlapping with 40Ar/39Ar age of 22.33&plusmn / 0.59 Ma and U-Pb age of 23.34&plusmn / 0.19 Ma from alterations. Sr-Nd isotope data are suggestive of a metasomatized subcontinental lithospheric mantle (SCLM) source for the magma. Alteration-mineralization pattern is defined by a series of overlapping halos characterized by sodic-calcic (plagioclase-pyroxene&plusmn / scapolite), calcic (garnet-pyroxene&plusmn / epidote), potassic (biotite+magnetite+chalcopyrite), hematite-limonite, and late stage (chalcedony-calcite+native Cu) alterations. Stable (&delta / 18O, &delta / 34S) and radiogenic (87Sr/86Sr,143Nd/144Nd) isotope compositions suggest a magmatic source for the fluids responsible for alteration-mineralization. Given the spatial-temporal association of alteration- mineralization with magmatic rocks, the hydrothermal system that controls mineralization in Samli appears to be linked with emplacement and cooling of Samli pluton. Samli Fe-oxide (+Cu&plusmn / Au) deposit has features characteristic for both skarn- and Iron-Oxide-Copper-Gold (IOCG) type deposits. The spatial and temporal association with a porphyritic intrusion, widespread calc-silicate assemblage, metal content (abundant Fe-oxide with high copper content) are similar to calcic Fe-Cu skarns, whereas low-Ti (&le / 0.05% TiO2) magnetite/hematite, low-S sulfides (chalcopyrite&gt / pyrite), high Cu (up to 6.78%) and moderate Au (up to 8.82 ppm) grades, local structural control in alteration-mineralization, and the derivation of the causative magma from a SCLM resembles the features pertinent to IOCG type mineralization. Therefore, Samli deposit is defined as a skarn type Fe-Cu mineralization with a potential for IOCG type deposit.

Visualization and study of reconformation of polyelectrolytes (PEs) of different architecture is of great fundamental and practical interest. Verification of theoretical predictions with experiment is of essential importance. On the other hand, a wide range of bottom-up techniques based on patterning of matter on the length scale of a few nanometers have been recently developed. Particularly interesting is the possibility of using self-assembled single molecule structures as templates for the deposition of inorganic matter, in particular metals. Synthetic &amp;quot;normal-sized&amp;quot; polymers of various architecture, like poly-2-vinylpyridine (P2VP) or polystyrene-poly(2-vynil pyridine) P2VP7-PS7 star-like block copolymer, adsorbed on solid substrates have been visualized for the first time with molecular resolution by AFM in different conformation. This finding allowed us to study largely discussed problem, a coil-to-globule transition of PEs. It was found that PE molecules undergo conformational transitions from stretched worm-like coil to compact globule via set of necklace-like globules, as the fraction of charged monomers decreases with an increase of pH and ionic strength. These results are in good agreement with recently developed DRO theory for weakly charged flexible PEs in poor solvent. The size of the deposited single molecules correlates very well with molecular dimensions in solution obtained in light scattering experiments. PE single molecules of various architectures was mineralized in different conformations that constitutes the route to nanoparticles with desired shape (including wire-shape and star-shaped), size, and composition (including metallic, magnetic and semiconductive nanoparticles). It was shown that molecular details of the adsorbed linear flexible PE molecules determine the dimensions of the nanostructures after metallization and that observed sizes are consistent with the decoration of single molecules with nanoclusters. Thus those metallized nanoparticles (cluster assembles) reflect the conformation of original adsorbed PE molecules. The dimensions of the obtained nanowires are significantly smaller than those previously reported. All of these features are of the potential benefit in applications for nanodevices. Metallization of the PS7-P2VP7 improves AFM resolution due to the selective deposition of Pd clusters along the P2VP chains. For the first time, the number of the P2VP second generation arms of the heteroarm block-copolymer was directly counted in the single molecule AFM experiment. Simple contrasting procedure was developed to improve AFM visualization of positively charged polymer chains deposited on the substrates of relatively high roughness. This method allows increasing the thickness of the resulting structures up to 10 nm, and, consequently, provide visualization of polymer chains on rough surfaces. This innovation is important for the development of single molecule experiments with polymer chains. The reaction of HCF-anion could be used for recognition of polycation molecules, when polycations, polyanions and neutral molecules coexist on the surface. Recently, the study was strongly restricted to atomically smooth surfaces. The contrasting procedure extends the range of substrates (Si-wafers, chemically modified or patterned Si-wafers, polished glasses, polymer films, etc) appropriate for the experiments. Thus, polymer single molecules can be considered not only as representative of the ensemble molecules, but also as individual nanoscale objects which can be used for future nanotechnology for the fabrication of single molecule electronic devices. Also these findings are important from fundamental point of view, since developed approach can be successfully applied for investigation of various &amp;quot;classical&amp;quot; problems in polymer science, such as polymer reconformation, interpolyelectrolyte complex formation, polymer diffusion, adsorption, etc.

<p>This thesis describes strategies for and examples ofcellulose fiber modification.The ability of an engineered biocatalyst, acellulose-binding module fused to the<i>Candida antarctica</i>lipase B, to catalyze ring-openingpolymerization of e-caprolactone in close proximity tocellulose fiber surfaces was explored. The water content in thesystem was found to regulate the polymer molecular weight,whereas the temperature primarily influenced the reaction rate.The hydrophobicity of the cellulose sample increased as aresult of the presence of surface-deposited polyester.</p><p>A two-step enzymatic method was also investigated. Here,Candida antarctica lipase B catalyzed the acylation ofxyloglucan oligosaccharides.The modified carbohydrates werethen incorporated into longer xyloglucan molecules through theaction of a xyloglucan endotransglycosylase. The modifiedxyloglucan chains were finally deposited on a cellulosesubstrate.</p><p>The action of<i>Candida antarctica</i>lipase B was further investigated inthe copolymerization of e-caprolactone and D,L-lactide.Copolymerizations with different e-caprolactone-to-D,L-lactideratios were carried out. Initially, the polymerization wasslowed by the presence of D,L-lactide. During this stage,D,L-lactide was consumed more rapidly than ε-caprolactoneand the incorporation occurred dimer-wise with regard to thelactic acid units.</p><p>Morphological studies on wood fibers were conducted using asol-gel mineralization method. The replicas produced werestudied, without additional sample preparation, by electronmicroscopy and nitrogen adsorption. Information concerning thestructure and accessibility of the porous fiber wall wasobtained. Studies of never-dried kraft pulp casts revealedmicro-cavities and cellulose fibrils with mean widths of 4.7(±2) and 3.6 (±1) nm, respectively.</p><p>Finally, cationic catalysis by simple carboxylic acids wasstudied. L-Lactic acid was shown to catalyze the ring-openingpolymerization of ε-caprolactone in bulk at 120 °C.The reaction was initiated with methylß-D-glucopyranoside, sucrose or raffinose, which resultedin carbohydrate-functionalized polyesters. The regioselectivityof the acylation was well in agreement with the correspondinglipase-catalyzed reaction. The polymerization was alsoinitiated with a hexahydroxy-functional compound, whichresulted in a dendrimer-like star polymer. The L-lactic acidwas readily recycled, which made consecutive reactions usingthe same catalyst possible.</p><p><b>Keywords:</b><i>Candida antarctica</i>lipase B, cationic catalysis,cellulose-binding module, dendrimer, enzymatic polymerization,fiber modification, silica-cast replica, sol-gelmineralization, organocatalysis, xyloglucanendotransglycosylase</p>