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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Studies on the molecular organisation of cartilage proteoglycans

Stimson, William Howard January 1970 (has links)
No description available.
12

Aspects of lipid peroxidation

Bascetta, Emanuele January 1983 (has links)
The photosensitised oxidation of the conjugated diene ester methyl octadeca-9E,11E-dienoate gives an unsaturated cyclic peroxide (epidioxide) in high yield. This has been characterised spectroscopically. The 9,12-peroxide undergoes facile rearrangement to the 9,12-furanoid ester under a variety of reaction conditions. Catalytic reduction of the unsaturated peroxide cleaves the O-O bond. Bromination and epoxidation give dibromo and epoxy esters in high yield with the peroxide group still intact. Methyl 9(10)-hydroperoxyoctadec-10(8)E-enoates (1a,b), produced by photosensitised oxidation of methyl oleate are suitable substrates for the synthesis of substituted dioxolanes. Peroxymercuration of (1) affords on hydrogenodemercuration methyl 8,10- and 9,11-epdioxyoctadecanoates (2a,b) in good yield (45-70%). Bromodemercuration yields the corresponding bromo substituted cyclic peroxides (3a,b) in higher yield (95%). Direct bromination of the allylic hydroperoxides (1a,b) also affords the bromo substituted cyclic peroxides (3a,b) in almost quantitative yield, presumably via a bromonium ion intermediate. The photosensitised oxidation of methyl vernolate, ricinoleate, 12-oxooctadec-9Z-enoate and 12-bromooctadec-9Z-enoate leads to allylic hydroperoxides with a shifted double bond as required by the ene-mechanism. The products are thermally sensitive and sample lifetimes are short. The silver trifluoroacetate assisted reaction of alkyl halides with hydrogen peroxide has been investigated. Reaction with methyl 12-bromostearate has furnished for the first time methyl 12-hydroperoxystearate in 34% isolated yield. Reaction with methyl 12-bromooleate, however, is more complicated and leads to the formation of cyclopropane hydroperoxides via a homoallylic cation rearrangement, and to hydroperoxy-epidioxides presumably via methyl 12-hydroperoxyoleate which we were unable to isolate. Methyl 12-t-butylperoxyoleate has been produced by reaction of methyl 12-bromooleate with t-butylhydroperoxide in the presence of silver trifluoroacetate. None of these transformations occur if the silver salt is replaced by silver acetate. 13C nmr chemical shifts are reported for a number of oxygenated long chain aliphatic compounds, including, epoxides alcohols, hydroperoxides and cyclic peroxides. The influence of the oxygenated functional groups on the chemical shifts of neighbouring carbons have been determined and a comprehensive set of chemical shift parameters derived. Results are discussed where applicable in terms of steric and electric field effects.
13

Adipose tissue lipid metabolism during pregnancy and lactation

Gillon, Keith R. W. January 1979 (has links)
1. The effect of pregnancy and lactation on some aspects of adipose tissue lipid metabolism in rat and mouse was studied. An attempt was made to elucidate control mechanisms for the changes in adipose tissue lipoprotein lipase activity in the rat during pregnancy and lactation. 2. Oxidation of glucose and synthesis of fatty acids from glucose by rat adipose tissue was either normal or elevated during early- and mid-pregnancy. Late pregnancy and lactation were characterized by low rates of glucose oxidation and fatty acid synthesis. 3. Rat adipose tissue lipoprotein lipase activity fell during early-pregnancy, prior to a recovery of enzyme activity in mid-pregnancy. The enzyme activity fell during late pregnancy to very low levels which were maintained until at least day 8 of lactation. Lipoprotein lipase activity in mouse adipose tissue fell during early-pregnancy and this low level of activity was maintained until day 17 of pregnancy, when an increase in activity occurred. The increased activity was maintained in early-lactation. 4. The response of rat adipose tissue in vitro to epinephrine stimulation in the release of FFA and glycerol was increased throughout pregnancy and early-lactation. Release of both FFA and glycerol was depressed on day 10 of lactation. Basal release of PPA increased but not significantly on days 7 and 12 of pregnancy and 3 of lactation. Glycerol release was elevated on day 12 of pregnancy and day 3 of lactation. Evidence is presented that the rate of FFA reesterification in the rat is decreased in early-to mid-pregnancy and increased in late pregnancy. Basal FFA and glycerol release in mouse adipose tissue in vitro were not significantly different from controls during pregnancy. FFA release was depressed on day 2 of lactation whereas glycerol release was increased. Both FFA and glycerol release in response to epinephrine stimulation increased, but not significantly, in late-pregnancy and markedly increased in early lactation. Prolactin injections had no significant effect on virgin rat adipose tissue lipoprotein lipase activity in vivo. Oestradiol benzoate markedly depressed lipoprotein lipase activity in virgin rat adipose tissue in vivo, and simultaneous administration of oestradiol benzoate plus prolactin did not decrease enzyme activity further. Simultaneous administration of oestradiol benzoate and a-ergocryptine produced a significant decrease in lipoprotein lipase activity in virgin rat adipose tissue in vivo. a-Ergocryptine administration to lactating rats reduced litter weight gain and increased the activity of lipoprotein lipase in adipose tissue in vivo.
14

Some studies on β-amylase from barley malt

Cook, Diane January 1975 (has links)
1. β-Amylase was prepared from barley malt by salt extraction and purified by ammonium sulphate fractionation and gel filtration on Sephadex G-25 followed by chromatography on DEAE-cellulose. Traces of β-amylase activity were removed by low temperature storage under acid conditions. β-Amylase so prepared released no soluble blue dye from chromogenic alpha-1,4-glucans. 2. The kinetic parameters (Km and Vm) of β-amylase hydrolysing alpha-1,4-glucan polymers were found to increase in the presence of β-amylase. This was explained in relation to the chain length of the substrate. 3. Amyloses of different degree of polymerization (DP) were prepared by ethanol fractionation of thymol-precipitated amylose from soluble starch. The values of Km and Vm for β-amylase were shown to decrease with an increase in the DP of the substrate. The values of Km for the non-reducing terminal and of for the internal portions of the substrate were found to be 0.001mM and 0,00015mM, respectively. 4. Series of dialdehyde amyloses and borohydride-reduced dialdehyde amyloses were prepared. An explanation was given for the dependence of Km and Vm upon the degree of oxidation of dialdehyde and reduced dialdehyde substrates. 5. Inhibition studies involving maltose, dialdehyde and reduced dialdehyde amyloses were carried out. A theory to explain the inhibitory effect of oxidized amyloses upon β-amylase activity was put forward. 6. Immobilised β-amylase derivatives prepared using AE-cellulose and polyaminostyrene supports were found to retain 18% and 9.1%, respectively, of the original activity of the soluble enzyme. The effects of pH and temperature upon the immobilised derivatives was compared with the effects upon soluble β-amylase and the apparent value s of Km and Vm (Km' and Vm') for soluble starch and of Ki (Ki') maltose were determined for each preparation. The action patterns of the soluble enzyme and the immobilised derivatives on amylose were investigated by plotting the decrease in blue value of the amylose substrate against the increase in the reducing power of the solution as hydrolysis proceeded and were confirmed by chromatographic analysis of the reaction products and intermediates of maltoheptaose hydrolysis and explained in terms of the alteration of enzyme affinity towards the substrate upon immobilisation.
15

Some effects of tumour growth upon rat muscle protein metabolism

Raymond, Michael John January 1972 (has links)
The effect of the growth of the Walker 256 carcinoma upon various aspects of rat diaphragm protein metabolism was investigated. Microscopic examination of diaphragm muscle from tumour-bearing rats revealed that the mean muscle fibre diameter was reduced compared with the normal animal. The extracellular space of both 'cut' and 'intact' diaphragm preparations was measured, using sorbitol and inulin as extracellular markers. No differences were observed in the extracellular space of both types of diaphragm preparation from normal and tumour-bearing rats, using sorbitol as the marker. With inulin as marker, the extracellular space was much smaller in the 'cut' diaphragm preparation from the tumour-bearing animal. Quantitative analysis of diaphragm muscle showed that the muscle lost weight during the growth of the tumour and that part of the weight loss was due to the loss of protein. Further, the loss of contractile proteins appeared to be more extensive than the loss of sarcoplasmic proteins. The in vitro incorporation of H-lysine into mixed proteins of rat diaphragm was shown to be greatly reduced by the growth of the tumour. This effect seemed to be directed principally at the myofibrillar proteins. The inhibition was not alleviated by the addition of either high concentrations of lysine or a mixture of amino-acids to the incubation medium. Normal diaphragm muscles incubated in serum from a tumour-bearing rat exhibited a greatly decreased up-take of labelled lysine into the myofibrillar proteins, and this pattern was not altered by supplementation of the medium with a mixture of amino-acids. The stimulatory effect of insulin upon muscle protein synthesis was greatly reduced by the growth of the tumour. In the normal animals studied, the effect of insulin seemed to be directed principally towards the myofibrillar proteins. A toxohormone fraction was prepared from Walker tumour tissue by an acetic acid extraction method, and purified by cation-exchange chromatography and gel-filtration. The biological activity of the preparation was assayed by measurement of its effect upon the plasma iron level in mice. The effect of the purified toxohormone fraction upon muscle protein synthesis was investigated both in vivo and in vitro, and the toxohormone was observed to exert a profound inhibitory effect upon the incorporation of labelled lysine into mixed intracellular muscle proteins.
16

Protein-carbohydrate interactions

Moothoo, Davina Noelle January 1998 (has links)
Carbohydrates are ubiquitous in nature and have become the focus of much scientific investigation. The proteins which recognise carbohydrates have become widely used in the areas of cell and molecular biology. Protein - carbohydrate interactions have been probed by theoretical, structural and thermodynamic techniques. The lectins are a class of carbohydrate binding proteins which bind carbohydrates through non covalent interactions such as hydrogen bonds and van der Waals interactions. In addition to these interactions, other factors play an important role in determining affinity such as carbohydrate conformation, solvent reorganisation and changes in the protein binding site. The legume lectin concanavalin A specifically recognises mannose and glucose terminal residues. The thermodynamics of concanavalin A binding to carbohydrates has been well documented. Concanavalin A binds the core trimannoside and pentasaccharide of the biantennary glycan found on mammalian cell surfaces with a high affinity. This thesis describes the structural basis of carbohydrate binding by con A, through the interpretation of crystal structures of concanavalin A bound with α1-2 mannobiose, methyl α1-2 mannobioside, the core pentasaccharide of the biantennary glycan and fructose. The structural information obtained from these structures is related to thermodynamic information available and unravels the importance of the role played by carbohydrate conformation, solvent reorganisation and statistical population of ligand in determining affinity. This work helps to develop an understanding of the physical basis of carbohydrate recognition.
17

The preparation, properties and applications of nylon-tube immobilised catalase

Ashworth, Stuart D. January 1975 (has links)
1. Several nylon-tube immobilised catalase derivatives were prepared. The method of preparation of nylon-tube for enzyme attachment was varied in an attempt to obtain the most active immobilised catalase derivative. 2. The stability of nylon-tube immobilised catalase derivatives during constant perfusion with hydrogen peroxide was examined in an attempt to prepare the most stable immobilised enzyme. 3. The peroxidatic activity associated with nylon-tube immobilised catalase derivatives was investigated. The effect of the chemistry of immobilisation, the length and diameter of the nylon-tube, and methanol concentration on the peroxidatic : catalatic activity ratio displayed by the immobilised catalase derivatives. 4. The applications of nylon-tube immobilised catalase derivatives in automated analysis was considered. Glucose was determined by four different assay protocols, involving 1) nylon-tube co-immobilised glucose oxidase and catalathe ; 2) nylon-tube immobilised derivatives of glucose oxidase and catalase in series ; 3) nylon-tube immobilised derivatives of glucose oxidase, catalase, and aldehyde dehydrogenase in series ; 4) nylon-tube co-immobilised glucose oxidase and catalase in conjunction with an oxygen electrode. 5. The peroxidatic activity of catalase was monitored using a) Hantzsoh reaction ; b) Aldehyde dehydrogenase ; and c) flow-through oxygen electrode. The four analytical systems were calibrated with aqueous glucose standards and the assay sensitivity and immobilised enzyme stability determined. Comparisons were drawn between the four methods for glucose determination using nylon-tube immobilised enzymes.
18

English 'treatises on physiognomy', c. 1500 - c. 1780

Porter, Martin January 1997 (has links)
Physiognomy is a ubiquitous subject of both pressing contemporary concern and genuine antiquarian early-modern interest. By examining the ways in which physiognomical treatises were read, this study reconstructs a way of looking at and listening to oneself, other people, nature and God, which I refer to throughout as the art of physiognomating. Known in manuscript form in England from at least the twelfth century onwards and probably long before, printed English 'treatises on physiognomy' were a small but constant feature of early modern European culture which, in part, explains the success of Lavater. Although direct translations of Continental versions, the English texts drew their physiognomical content from a handful of Greek, Arabic and medieval Latin authorities. They were owned and read by people of all ages, from a variety of different social groupings and geographical areas. Physiognomating was a multi-faceted phenomenon of the <i>longue durée</i>, understood by some as a natural language based on instinct, a magical knowledge based on divine revelation, a branch of natural philosophy, an aspect of medicine, moral philosophy, political science, humoral theory, astrology, fortune-telling, even game-playing. The meanings of some physical features were more or less consistently agreed upon, whilst many were also supported by physiognomical proverbs and adages. Long understood as an aspect of knowing oneself (<i>nosce teipsum</i>), physiognomy has much to say about early modern conceptions of gender, virtue and beauty as well as the language in which early modern people understood and experienced both their own bodies, the civility of themselves and other people, as well as the character of nature and, ultimately, God. Early modern printed expositions of physiognomical doctrine migrated through a number of generically distinct texts. This migration provides evidence of the ways in which this form of looking and listening - the <i>inspectio sapiens/inspectio prudens</i> - was conceived and used at different times across the period. The readers' graffiti found in the extant copies of these texts show how physiognomating ranged from being the performance of a confessional prayer in the guise of a private medico-moral self-inspection (possibly carried outwith the aid of a looking-glass) in the earlier part of the period, to a more public form of bawdy parlour game in the later part of the period. However, it was predominantly a form of political science, a utilitarian visual ideology for those everyday 'negotiations' with other people, with the aim of achieving business and procreational success in what was seen by many as the hazardous realm of the 'brutish sort' and the public sphere. Whilst physiognomy was central to John Dee's conception of science, Francis Bacon felt it needed cleansing of superstition. Most subsequent philosophers relegated it to the realm of mere opinion. Taught to children and examined at university, physiognomy was also practised by gypsies, vagabonds, astrologers, physicians, priests, ambassadors, lawyers, teachers and parents. This physiognomical gaze was also used for the choosing of a physician, a soldier, a partner or even a hat. The most prominent feature of the early modern reconfiguration of this art of physiognomating was the dissolution of the understanding of the self and other people as a constellation of natural Aristotelian and Christian ethical entities in a more fluid, culturally constructed language drawn from the characters of everyday life.
19

Il De liberis educandis di Guarino Guarini: Testo latino, traduzione e commento storico-filologico = Guarino Guarini’s De liberis educandis: Latin text, Italian translation and historical-philological commentary

Cassi, Romana January 2016 (has links)
Thesis advisor: Franco Mormando / Tra il 1410 e 1411, di ritorno dal suo viaggio di formazione in Grecia, il giovane Guarino tradusse in latino il Περὶ παιδῶν αγογὴς, opuscolo contenuto nel corpus dei Moralia e attribuito ad un maestro del circolo di Plutarco. Il testo greco riassumeva concetti educativi fondamentali nell’antichità, suggerendo un modello di educazione che mirava a formare un uomo laico, cittadino consapevole dei suoi doveri familiari, civili e religiosi. Questo concetto educativo, consono alla sensibilità umanistica di Guarino, spiega la sua scelta di tradurre in latino l’opera greca. Il De liberis educandis rappresenta, dunque, dal punto di vista del contenuto, un importante divulgatore di principi educativi per i secoli a venire e, dal punto di vista linguistico, una preziosa fucina di quel nuovo latino che andava formandosi all’inizio del XV secolo e di cui Guarino è uno dei primi artefici. Questo studio si propone di sottrarre il De liberis educandis dall’ombra e di aggiungere osservazioni sulla controversa attività di Guarino come traduttore. Sulla base di un dettagliato confronto linguistico tra l’originale greco e la versione latina di età umanistica, si può concludere che Guarino traduceva il testo greco con precisione, pur permettendosi qualche libertà dal punto di vista linguistico e culturale, come si dimostrerà con precisi riferimenti testuali. Il raffronto con l’originale greco rappresenta anche la base per avviare un’edizione critica dell’opuscolo latino che, assieme ad una traduzione in italiano, non è mai stata affrontata prima d’ora. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Romance Languages and Literatures.
20

Toward a &ldquo;Green&rdquo; Organ: Organ Building and Sustainability

January 2014 (has links)
abstract: This study examines the effectiveness of various types of alternative resources in organ building in order to determine whether a change to more sustainable materials would benefit or hinder the overall sound production of the instrument. The qualities of the metals and woods currently used in organ production (e.g. lead, walnut, etc.) have been prized for centuries, so the substitution of different, more sustainable materials must be considered with regards to the sonic alterations, as well as the financial implications, of using alternatives to make the organ more &ldquo;green.&rdquo; Five organ builders were interviewed regarding their views on sustainable materials. In addition, the author consulted the websites of nine national and four international organ builders for information about sustainability, indicating that each organ builder defines the term somewhat differently. Decisions on the woods and metals to be used in building or refurbishing an existing organ are based more on the visual appearance, the sound desired, and the potential for reuse of existing materials. A number of sustainability practices are currently in use by organ builders in the United States and Europe. These include the reuse of transportation boxes, efforts towards recycled metal and wood pipework, and the use of high efficiency lighting. The investigations into sustainable practice that are presented here document a variety of approaches to sustainability in organ building in the United States, Canada and Europe. This research should assist in the evaluation of further efforts to conserve valuable resources while ensuring the high quality of sound that has characterized the organ throughout its long history. / Dissertation/Thesis / Doctoral Dissertation Music 2014

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