The release of toxic metal species is of concern due to their detrimental effects on the environment and human health. Industrial effluents are a major source of mobilised metal species. Suitable technologies are needed to sequester toxic metal species at the point of source. Biosorption, which is based on the passive adsorption of contaminants onto biological materials, promises to offer an effective alternative or complementary step to existing treatment methods. However, to date there has been no widespread commercialisation of the technique. This is partly due to an insufficient understanding of the complex underlying mechanisms which makes it difficult to select suitable biomass for specific remediation problems and to predict process performance. This study characterised two gram-positive, thermophilic bacteria, Anoxybacillus flavithermus (BF) and Geobacillus stearothermophilus (BS), harvested at two different growth times, with regard to their acid-base and Cd�⁺ adsorption behaviour. The aim was to investigate the metal cation adsorption properties of thermophilic bacteria which has not been studied previously, and to gain a better understanding of the interactions responsible for bacterial metal cation adsorption. Experimental techniques employed in this study included microscopy to establish cell and cell wall morphology, batch acid-base and Cd�⁺ adsorption experiments to quantify proton active surface functional groups and Cd�⁺ adsorption, electrophoretic mobility measurements to assess the overall surface charge of the bacteria and in situ attenuated total reflection infrared (ATR-IR) spectroscopy to reveal the chemical identities of functional groups. Chemical equilibrium models based on batch acid-base titration and electrophoretic mobility data were developed to quantitatively describe proton active surface functional groups. These groups can also interact with metal cations. It was found that growth time was an important factor in all experiments with the differences between growth times often being more pronounced than the differences between the two bacterial strains. Microscopy revealed a gram-positive cell wall structure with different widths and staining behaviour for exponential phase cells of BF and BS. Stationary / death phase cells showed disintegrating cell walls. Acid-base titrations indicated that all cells possessed buffering capacity over the whole investigated pH range (pH 2 - 10). From electrophoretic mobility measurements, isoelectric points of ~ 3.2 for BF and < 1.8 and ~ 4.2 for exponential and stationary / death phase cells of BS respectively were estimated. Chemical equilibrium models including a Donnan electrostatic model were derived which described both the batch acid-base titration data and the electrophoretic mobility data reasonably well, although a comparison with IR data suggested room for further improvement. In situ ATR-IR spectroscopy of hydrated bacterial cells at various pH values revealed amide and carboxyl groups and a contribution from phosphate / polysaccharide moieties. Group specific interactions with Cd�⁺ were not detected, however, a partially reversible absorbance increase of all peaks suggested conformational changes in the presence of Cd�⁺. BF and BS adsorbed ~ 70 [mu]mol Cd�⁺ (g dry bacterial)⁻� at pH 5 in 0.01 M NaNO₃. Release of major cations occurred concomitantly with Cd�⁺ adsorption. The buffering and Cd�⁺-binding capacities of BF and BS were found to be comparable to those of mesophilic bacteria and ion exchange was identified as an important adsorption mechanism.

The aim of Part One was to discover and investigate the physical and chemical properties of coal minesoils occurring within the Big South Fork National River and Recreation Area (BSF) in order to better understand the nature of these anthropogenic soils. In particular, this information was to identify which, if any, un-reclaimed or recently reclaimed minesoils were actively producing acid mine drainage (AMD) and what properties were inhibiting revegetation. Historical knowledge and maps were used to locate more than 30 un-reclaimed and reclaimed minesoil sites, which were mapped with GPS. Soil profiles were exposed on 18 sites and grab samples taken on another 12. The morphological properties of each full profile were described according to the National Soil Survey Handbook and samples were taken from each horizon. Chemical properties analyzed for include: particle size, acid-base account, pH, exchangeable aluminum, manganese oxides, soil organic carbon, cation-exchange capacity, exchangeable bases, Mehlich I-extractable elements, and total elemental concentrations. Significant differences in the following properties (averaged) were discovered between the un-reclaimed and reclaimed minesoils: slope, percent rock fragments, dominant lithology, net neutralization potential, pH, extractable aluminum, base saturation, several Mehlich I-extractable nutrients and total elemental concentrations. Hierarchical clustering analysis revealed similar findings and also highlighted instances where reclaimed minesoils were statistically more similar to un-reclaimed minesoils than to other reclaimed minesoils. This indicated that reclamation efforts may not have been completely successful on these sites. In Part Two, minesoil profiles were classified according to Soil Taxonomy and according to proposed amendments by the International Committee for Anthropogenic Soils (ICOMANTH). The ICOMANTH amendments provided more informative classifications for coal minesoils in the BSF however, shortcomings were noted. Additional recommendations were made and the minesoils were again classified according to these recommendations. Compared to both the Soil Taxonomy and the ICOMANTH classifications, those according to the proposed additional amendments revealed more of the unique properties of the minesoils studied in this project. The results of this study can aid the National Park Service with future land management of the minesoils located within the BSF boundaries and other users of drastically disturbed minesoils.

Relative changes are detectable in the blood of end-stage renal disease (ESRD) patients during hemodialysis (HD) treatment using optical spectroscopy. However, the potential impacts of several confounding factors that could affect the detection of these changes have not been evaluated. The objectives of this thesis were to: 1) investigate how the variations and/or changes in acid-base and oxygen parameters during HD treatment can affect the optical signature of whole blood of ESRD patients, 2) to investigate the effect of heparin on the optical properties of whole blood and its impact on our method. Blood samples were drawn from 23 ESRD patients at 5 time points during a 4 hour HD treatment and sent for blood gas and blood spectroscopy analyses. No significant correlations were found between the changes in the blood transmittance spectra and acid-base and oxygen parameters. This indicates that the perturbations in these parameters due to HD procedures do not confound the detection of changes in the blood transmittance spectra of ESRD patients during HD treatment. Additionally, the effect of heparin in modifying the optical properties of whole blood does not confound the detection of changes in the blood of ESRD patients due to HD treatment using whole blood-based optical spectroscopy. ANOVA revealed significant (P<0.05) measurable changes in the blood transmittance spectra of ESRD patients during HD treatment. Significant spectral differences (P<0.05) were found between ESRD patients. The lack of uniform spectral characteristics across patients is

Relative changes are detectable in the blood of end-stage renal disease (ESRD) patients during hemodialysis (HD) treatment using optical spectroscopy. However, the potential impacts of several confounding factors that could affect the detection of these changes have not been evaluated. The objectives of this thesis were to: 1) investigate how the variations and/or changes in acid-base and oxygen parameters during HD treatment can affect the optical signature of whole blood of ESRD patients, 2) to investigate the effect of heparin on the optical properties of whole blood and its impact on our method. Blood samples were drawn from 23 ESRD patients at 5 time points during a 4 hour HD treatment and sent for blood gas and blood spectroscopy analyses. No significant correlations were found between the changes in the blood transmittance spectra and acid-base and oxygen parameters. This indicates that the perturbations in these parameters due to HD procedures do not confound the detection of changes in the blood transmittance spectra of ESRD patients during HD treatment. Additionally, the effect of heparin in modifying the optical properties of whole blood does not confound the detection of changes in the blood of ESRD patients due to HD treatment using whole blood-based optical spectroscopy. ANOVA revealed significant (P<0.05) measurable changes in the blood transmittance spectra of ESRD patients during HD treatment. Significant spectral differences (P<0.05) were found between ESRD patients. The lack of uniform spectral characteristics across patients is

No description available.

Synthesis and evaluation of catalytic performances of novel bifunctional 2- aminoDMAP-Thiourea/ Sulfonamide/ Squaramide organocatalysts derived from trans-(R,R)-cyclohexane-1,2-diamine forms the main goal of this thesis. For this purpose, direct selective mono-N-pyridilization of trans-(R,R)-cyclohexane-1,2- diamine via Pd and Cu catalysis is described successfully first. Facile preparation of chiral 2-aminoDMAP core catalaphore led to the development of various 2- aminoDMAP- Thiourea/ Sulfonamides/ Squaramides as bifunctional acid/base organocatalyst libraries (most in two-steps overall) which showed good results in asymmetric conjugate addition of 1,3-dicarbonyls to trans-(&beta / )-nitrostyrene. Enantiomeric excesses (ee) up to 93% were attained.

<p>Wood is often combined with other materials such as thermoplastics, adhesives and coatings. In general, combinations of wood and polymers especially in outdoor exposure have poor long-term durability. This behaviour can be related to an insufficient wood-polymer adhesion due to the low intrinsic compatibility between the wood substance and the polymers used. Another source for woodpolymer de-bonding is the high hygroscopicity of wood and great difference in hygro-thermal properties between the components.</p><p> The basic conceptual idea related to this work is to reduce the hygrosensitivity of wood by applying different wood modification methods, in particular, acetylation, furfurylation and heat treatment. The effects of such chemical modifications of wood, also accompanied with ageing effects, on its adhesion properties with commonly used synthetic polymers are, however, not well understood. In this context, the over-all purpose of this thesis is to achieve a better understanding of wood-polymer adhesion and interfacial forces which also may guide us to tailor the interaction between modified wood and e.g. thermoplastics and adhesives. The main focus of this thesis is therefore to apply contact angle analysis based on the Chang-Qin-Chen (CQC) Lewis acid-base model in order to estimate the work of adhesion (<i>W</i><i>a</i>) between the wood, modified wood and certain polymers. Contact angle measurements on wood samples were performed based on the Wilhelm plate principle. Related to this, an effort was also made to characterize the studied modified wood surfaces according to morphology and chemical composition. The methods that have been used are low vacuum scanning electron microscopy (LV-SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). </p><p>Results show that so-called interaction parameters can be successfully estimated for prediction of <i>W</i><i>a</i> between wood and polymers using the applied CQC model. Furthermore, such wetting analysis was successfully related to spectroscopic findings of the chemical composition of the wood samples surface. Ageing effects, i.e. the time after preparation of the wood surface, play a central role for the surface characteristics. In most cases, ageing resulted in a significant decrease of <i>W</i><i>a</i> between wood and water and a moderate decrease between wood and thermoplastics. The surface characteristics of acetylated wood were, however, more stable over time compared to unmodified, furfurylated and heat treated wood. The predicted <i>W</i><i>a</i>with the adhesives for heat treated and acetylated wood was increased due to ageing. Future work is planned to involve studies in order to relate such predicted adhesion properties with the actual performance of various wood-polymer systems.</p>

Direct methanol fuel cells (DMFC) are being investigated for use as low-power electrochemical energy conversion devices. These types of fuel cells can be useful for portable electronics. The polymer electrolyte membrane plays a critical role in the overall performance of DMFC. The commercially available membrane, Nafion, suffers from high methanol permeability and a resulting methanol crossover from the anode to the cathode; it is also expensive. Accordingly, alternative membrane materials, such as sulfonated hydrocarbons, are intensively pursued for DMFC. For example, sulfonated poly (ether ether ketone) (SPEEK) and sulfonated polysulfone (SPsf) are two such candidates. This thesis focuses first on a simple synthesis method for a cross-linked sulfonated polysulfone membrane. Sulfonated polysulfone (Psf) membranes, with high IEC (1.4 - 2.2 meq/g), were characterized by nuclear magnetic resonance spectroscopy (NMR), proton conductivity, and water uptake. The degree of sulfonation was calculated by NMR and verified by acid-base titration analysis. Although the membranes showed good proton conductivity, they suffered from excessive swelling at high temperatures. Furthermore, the post-sulfonation of a carboxyl-substituted polysulfone (Psf-COOH) was carried out with trimethylsilyl chlorosulfonate, and solubility issues of the Psf-COOH in chlorinated solvents led to difficulty in controlling the degree of sulfonation (DS) and in purification. Accordingly, this approach to cross-linking sulfonated polysulfone was rejected as a viable method. This thesis then focused on the investigation of the mechanical properties of acid-base blend membranes based on SPEEK and heterocycle-tethered Psf and cross-linked membranes based on SPEEK that were previously reported by our group; these membranes were known to exhibit good performance in DMFC. However, the assessment of the mechanical stability of any new membranes developed is critical for their practical viability in DMFC. Accordingly, the mechanical strength and ductility of these membranes were investigated and compared for various membrane compositions. The acid-base blend membranes investigated consisted of SPEEK (acidic polymer) and a heterocycle-tethered Psf (basic polymer); for example, blends consisting of SPEEK and amino-benzimidazole-tethered Psf (SPEEK/Psf-ABIm) and SPEEK and benzotriazole tethered Psf (SPEEK/Psf-Btraz) were investigated. The cross-linked SPEEK was made by Friedel-Craft acylation with Psf-COOH (DS = 1 or 2). The two blend membranes showed superior mechanical properties compared to Nafion 115 and comparable to plain SPEEK. The crosslinked membranes showed good mechanical properties and better strength than Nafion 115, but they were more brittle than both Nafion 115 and plain SPEEK. Further optimization of cross-linking conditions is necessary to produce the best performing membrane. / text

This study explored what cognitive resources (i.e., units of knowledge necessary to learn) first-semester organic chemistry students used to make decisions about acid strength and how those resources guided the prediction, explanation and justification of trends in acid strength. We were specifically interested in the identifying and characterizing the mental models, assumptions and heuristics that students relied upon to make their decisions, in most cases under time constraints. The views about acids and acid strength were investigated for twenty undergraduate students. Data sources for this study included written responses and individual interviews.The data was analyzed using a qualitative methodology to answer five research questions. Data analysis regarding these research questions was based on existing theoretical frameworks: problem representation (Chi, Feltovich & Glaser, 1981), mental models (Johnson-Laird, 1983); intuitive assumptions (Talanquer, 2006), and heuristics (Evans, 2008). These frameworks were combined to develop the framework from which our data were analyzed.Results indicated that first-semester organic chemistry students' use of cognitive resources was complex and dependent on their understanding of the behavior of acids. Expressed mental models were generated using prior knowledge and assumptions about acids and acid strength; these models were then employed to make decisions. Explicit and implicit features of the compounds in each task mediated participants' attention, which triggered the use of a very limited number of heuristics, or shortcut reasoning strategies. Many students, however, were able to apply more effortful analytic reasoning, though correct trends were predicted infrequently. Most students continued to use their mental models, assumptions and heuristics to explain a given trend in acid strength and to justify their predicted trends, but the tasks influenced a few students to shift from one model to another model. An emergent finding from this project was that the problem representation greatly influenced students' ability to make correct predictions in acid strength.

Das Ziel dieser Arbeit war es, den Einfluss unterschiedlich zusammengesetzter Tränken auf den Säuren-Basen-Haushalt bei Kälbern mit experimentell induzierter metabolischer Azidose zu untersuchen. Bei gesunden Kälbern konnte nachgewiesen werden, dass die Fütterung von milchbasierten ORL mit einer [SID3] ≥92 mmol/l eine Erhöhung der Plasma-[SID3] zur Folge hat (BACHMANN et al. 2009b) und damit eine alkalische Wirkung auf den SBS. Zu prüfen galt die Hypothese, ob es bei Kälbern mit experimentell induzierter metabolischer Azidose zu einem stärkeren alkalisierenden Effekt nach Gabe einer Tränke mit einer hohen [SID3] kommt. Bessere alkalisierende Eigenschaften einer Tränke könnten potentiell genutzt werden, um den Genesungsprozess von Kälbern mit metabolischer Azidose zu beschleunigen. Material und Methoden Zur Verfügung standen zwölf Kälber der Rasse Holstein-Friesian im Alter von weniger als vier Lebenswochen. Unter Verwendung von in der Literatur beschriebenen Induktionsprotokollen konnte per Infusion bei jeweils sechs Tieren eine manifeste hyperchlorämische Azidose und bei weiteren sechs Kälbern eine D-/L-Laktatazidose ausgelöst werden. Die Tiere wurden im Anschluss mit Milchaustauscher, wasser- oder milchaustauscher-basierter oraler Rehydratationslösung getränkt bzw. blieben im nüchternen Zustand. Zur Bestimmung von Stewart-Parametern des Säuren-Basen-Haushaltes im Plasma wurden nach einem festgelegten zeitlichen Schema vor und nach Induktion sowie vor und nach der Tränkegabe venöse Blutproben entnommen. Ergebnisse Bedingt durch die Einleitungsprotokolle war die Interpretation der Messergebnisse durch den starken Anstieg des Plasmavolumens bedeutend erschwert. Die eingesetzten Induktionsprotokolle sind nicht für Untersuchungen des Säuren-Basen-Haushaltes bei Kälbern nach unterschiedlicher Fütterung geeignet. Aus diesem Grund kann die aufgestellte Hypothese, dass die Verabreichung von milchaustauscher-basierter ORL zu einer besseren alkalischen Wirkung bei Kälbern mit metabolischer Azidose führt, anhand der vorliegenden Ergebnisse weder abgelehnt noch bestätigt werden. Einige Untersuchungsergebnisse zeigten positive Effekte auf Parameter des SBS bei Kälbern, denen eine Tränke verabreicht wurde, im Vergleich zu nüchternen Tieren. Diese Parameter waren die Plasma-D-Laktatkonzentration, die Strong Ion Difference [SID3] und [SID4] und ionisiertes Calcium [Ca2+]. Die Effekte waren nicht auf eine bestimmte der drei eingesetzten Tränkevarianten zurückzuführen. Weiterhin konnte gezeigt werden, dass ein quadratischer Zusammenhang zwischen der berechneten Variable Strong Ion Gap [SIGAlb/TP] und den gemessenen D-/L-Laktatkonzentrationen im Plasma besteht. Dies könnte zukünftig genutzt werden, um Faktoren zu etablieren, welche die Ableitung der Plasma-D-/L-Laktatkonzentration bei durchfallkranken Kälbern mit ZNS-Symptomatik aus gängigen Parametern ermöglicht, ohne die Laktatkonzentration direkt messen zu müssen. Schlussfolgerungen Für zukünftige Untersuchungen dieser Art wäre ein Induktionsprotokoll wünschenswert, das sowohl eine metabolische Azidose bei gleichzeitiger Dehydratation der Kälber vereint und so die metabolischen Bedingungen durchfallkranker Kälber simuliert. Die Gabe von ORL als direkte Einmischung in Milch bzw. MAT wird kritisch betrachtet. Ein negativer Effekt bei der Gabe von MAT-basierter ORL konnte bei diesen Untersuchungen auf keinen der bestimmten Parameter des SBS im Vergleich zu den anderen Tränkezusammensetzungen festgestellt werden. Klinische Nebenwirkungen Bei dieser Untersuchung traten nach der mehrfachen Infusion von D-/L-Laktat unerwartete Nebenwirkungen auf. Die Verabreichung führte zu starken Irritationen der Vena jugularis externa und zu Ödembildungen. Erhöhte D-Laktatkonzentrationen werden beim Menschen und verschiedenen Tierarten als Marker für traumatische Prozesse, Ischämie, Diabetes, gastrointestinale und neurologische Störungen diskutiert. Die weitere gezielte Untersuchung des Einflusses der wiederholten oder anhaltenden Einwirkung von D-Laktat auf Epithelzellen könnte nach den vorliegenden Untersuchungsergebnissen einen weiteren Anhaltspunkt für die Aufklärung der genauen pathologischen Mechanismen des D-Laktates bieten.