No description available.

No / The performance of batch reactive distillation process involving the esterification of acetic acid with methanol to produce methyl acetate and water is considered in this work. Two cases studies with varying amount of the reactants are considered. The reflux ratio (single time interval) is selected as the control variable to be optimised (treated as piecewise constant) for different but fixed batch time ranging from 5 to 15 h, so as to maximise the conversion of methanol subject to product purity of methyl acetate. The dynamic optimisation problem is converted to a nonlinear programming problem by Control Vector Parameterization (CVP) technique and is solved by using efficient SQP method. The optimisation results show that as the methanol and methyl acetate are wide boiling, the separation of methyl acetate is easier without losing much of methanol reactant. The conversion improves by 6.4 % due to sufficient amount of acetic acid being reacted with methanol. Moreover an excess of acetic acid leads to high operation temperature and therefore high reflux operation (to reduce loss of methanol from the top of the column) to maximise the conversion.

Tuberculosis, caused by Mycobacterium tuberculosis (MTB), is a common and potentially lethal infectious human disease. Rifampicin is a front line anti-tuberculosis drug usually prescribed in combination with isoniazid, pyrazinamide and streptomycin for a period of six to seven months. When given orally for the treatment of MTB, rifampicin exhibits low bioavailability. Recent attempts to increase bioavailability and decrease dosage of anti-tuberculosis drugs have focused on creating polymer coated rifampicin nanoparticles. The research effort presented in this thesis evaluates the formation, characterization and relative bioavailability of rifampicin loaded carboxymethylcellulose acetate butyrate (CMCAB) particles using two different formulation techniques. Multi inlet vortex mixer (MIVM) and manual spray drying techniques were used to form the rifampicin containing CMCAB particles. Characterization studies and analyses of particles revealed differences in particle sizes, shapes and drug loading between the different particle formulation techniques. In vivo pharmacokinetic studies in BALB/c mice indicate that a single dose of rifampicin laden CMCAB spray dried particle formulations are able to improve pharmacokinetic parameters including relative bioavailability of rifampicin compared to that of the free drug form at the same concentration. / Master of Science

Alginates are (1and4) linked linear copolysaccharides composed of B-D-mannuronic acid (M) and its C-5 epimer, a-L-guluronic acid (G). Several strategies to synthesize organically modified alginate derivatives have been reported, but almost all chemistries are performed in either aqueous or aqueous-organic media. The ability to react alginates homogeneously in organic solvents would open up access to a wide range of new chemistries and derivatives. However, past attempts have been restricted by the absence of methods for alginate dissolution in organic media. We therefore report a strategy to solubilize tetrabutylammonium (TBA) salts of alginic acid in polar aprotic solvents containing tetrabutylammonium fluoride (TBAF). Acylation of TBA-alginate was performed in DMSO/TBAF to get products with DSacetyl up to ~ 1.0. We further report that by using appropriate solvent conditions, placement of acyl groups can be controlled to achieve either random or M-selective substitution. Alginate acetates synthesized in an M-selective fashion were used to study the ability of these derivatives to form Ca-crosslinked hydrogels. Detailed structure-property analyses were performed to identify acetylation reaction conditions and product properties that may be ideal for hydrogel formation. Furthermore, alginate esters were synthesized via modification of carboxylate groups on the backbone. These derivatives dissolved in polar aprotic solvents without the need to add TBAF. A proof of concept study showed their utility in the solubility enhancement of the poorly water soluble flavonoid naringenin. / Ph. D.

no abstract provided by author / Master of Science

The objective was to compare the effects of three corticosteroids at various equimolar concentrations on equine articular explant co-cultures in an inflammatory environment. Synovial and osteochondral explant co-cultures from 6 equine cadavers were exposed to IL-1β (10 ng/mL) and various concentrations (10-4, 10-7, or 10-10 M) of MPA, TA, IPA. Concentrations of PGE2, MMP-13, LDH, and GAG in media were determined at 48 and 96 hours. Results indicated wells with low concentrations of MPA (10-7 and 10-10 M at 48 and 96 hours), TA (10-7 M at 48 hours and 10-7 and 10-10 M at 48 and 96 hours), and IPA (10-10 M at 48 hours) had significantly less PGE2 than positive control samples. Groups with low concentrations (10-7 and 10-10 M) of MPA and TA had significantly less PGE2 than the highest concentration (10-4 M) at 48 hours. Significantly less MMP-13 was detected for all concentrations of MPA, TA, and IPA at 96 hours. The LDH assay results indicated cytotoxicity only for samples treated with IPA at 10-4 M at 48 and 96 hours. GAG was significantly lower for samples treated with TA 10-7 M at 48 hours and MPA 10-10 M at 96 hours versus positive controls. These findings suggest corticosteroids at low concentrations mitigated the inflammatory and catabolic effects of IL-1β to a greater extent than high concentrations. Effects of IPA and MPA were similar to TA at clinically relevant low equimolar concentrations. / Master of Science / Recent data suggest that isoflupredone acetate is commonly administered intra-articularly for treatment of joint disease (osteoarthritis) in horses. Although much data has been published regarding effects of other corticosteroids on cartilage, to our knowledge there have been no similar studies of the effects of isoflupredone acetate. With increased scrutiny from the general public and more stringent control of medication use by regulatory agencies, determination of information regarding such common intra-articular therapies is imperative. In addition, prior studies have only evaluated the effects of corticosteroids on cartilage, whereas other joint tissues (subchondral bone and synovium) have been shown to be important to the biological responses of joints. Therefore, to more closely simulate the natural joint environment, this study was conducted with a co-culture model incorporating synovial tissue, articular cartilage, and subchondral bone within an inflammatory environment (via stimulation with interleukin-1β). The effects of various concentrations of methylprednisolone acetate, triamcinolone acetonide, and isoflupredone acetate on joint tissues were determined via measurement of selected biomarkers. This study provided the first data regarding biological effects of IPA on joint tissues of horses, and the first comparison of such effects with those of other corticosteroids commonly used intra-articularly for the treatment of joint disease in horses.

This thesis aims to examine the issues involved in utilising digital images and assess whether image processing techniques can be used as a cost-effective method of reconstructing the image found in a deteriorated cellulose acetate negative. Negatives affected by the vinegar syndrome are found in large numbers within Australian institutions. This was confirmed by a survey (using a questionnaire) undertaken at the National Library of Australia in 2000. The survey also found that although these collections are large, and hence the level of deterioration variable, little could be done to restore any of the negatives once deterioration had begun. Storing negatives at low temperature and low relative humidity slows down the breakdown of cellulose acetate; however, it cannot reverse the process once it has commenced. Although removing the gelatine pellicular from the deteriorated cellulose acetate support (making the image easier to view) a possible method of restoration, this becomes unfeasible when dealing with a large collection. As a result, how to manage cellulose acetate negatives once they have deteriorated becomes problematic. Image-processing techniques used to digitally restore these negatives were examined via a series of case studies. These examinations were undertaken using two software packages-the Image Processing Tool kit (IPTK) and OPTIMAS. Deteriorated cellulose acetate negatives were scanned, then a number of program filters were applied to the digital image to determine whether disfiguring elements (referred to as channelling elements) resulting from the deteriorated support could be digitally removed. IPTK and OPTIMAS were not completely successful in removing the deteriorated elements from the digital version. The results highlighted that a number of issues relating to the use of digital technology needed to be addressed. These issues included knowledge of basic technical terms, an understanding of digital language, and how to include the use of digital technology into a long-term strategy for archiving a digitised collection. This thesis showed that issues relating to utilising digital systems could be addressed by implementing a preservation management plan. A preservation management plan can be used to incorporate the goals of digitising, the long-term issues of retaining digital files, ongoing access relating to the digital file, hardware and software, and the importance of having the relevant expertise when undertaking such a project. Due to the limitations of the printed hardcopy displaying features in a number of the images (figures) outlined in this thesis, a compact disk (CD) has been included with this submission and can be found at the end of this document.

Thesis (Ph.D. in Molecular Biology) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 89-109 and 224-228).

Syntrophic acetate oxidizing bacteria convert acetate into hydrogen and carbon dioxide and through the mutualistic syntrophic partnership with methanogens the products are further converted to methane in biogas processes operating at high ammonia concentrations. There is very little known about SAOBs, only five have been characterized and had their genome analyzed. The aim of this project was to gain further knowledge about the methane producing pathway of SAOBs with a proteomic approach. Proteins were extracted from biogas sludge with a phenol-based approach and trypsin digestion and peptide recovery were performed using the Suspension Trapping method. Measurement of the peptide content was made with LC-MS/MS. The peptide profiles obtained were screened for the proteins expressed of the mesophilic SAOB Syntrophaceticus schinkii. The data supports earlier suggestions that it utilizes the Wood-Ljungdahl pathway for hydrogen production. Furthermore, the peptide profile revealed that enzymes for the glycine reductase complex and the glycine cleavage system were expressed during high ammonia concentration, indicating a potential role of these enzymes in the methane producing pathway. However, due to partial failure of the sample preparation for mass spectrometry measurements no quantification conclusions could be made. A discussion on how to further improve sample preparation methods as well as how to access the proteome to a large extent is presented.

<p> The biosynthesis of lycopodine was studied by feeding radioactive acetate, acetoacetato, lysine and pelletierine to Lycopodium tristachyum. Partial degration of the radioactive lycopodine recovered from these experiments revealed specific incorporation of these precursors. The labeling pattern obtained is discussed in the light of the two major blogenetic hypothesis advanced for the Lycopodium alkaloids. </p> <p> The results obtained disproved Conroy's polyacetate hypothesis. They are consistent with the hypothesis that regards these alkaloids derived from lysine and acetate. </p> / Thesis / Doctor of Philosophy (PhD)