Cluster management synergy valuation: Synthesis and illustration of a discounted cash flow synergy valuation model for cluster management organisations

The practice of cluster management has become an integral component to the modern cluster business environment. This research develops a framework for the valuation of synergies generated by a cluster management organisation (CMO) to be used as either a method of (ex-post) management evaluation or (ex-ante) for capital budgeting purposes. The theoretical framework is synthesised from clustering and business alliance (predominantly Mergers and Acquisitions (M&A) and Joint Ventures (JV)), literature. The case of the South African Furniture Initiative (SAFI) was used to inform model development and to illustrate practical application of the theoretical synergy valuation model. The case study found that the synergy valuation model faces problems with practical application due to the wide variety of activities commonly associated with CMO goals and objectives. It concludes that even though a synergy framework would provide a useful tool for evaluation and capital budgeting, further research is required to develop a more accurate method of impact estimation

The development and evaluation of a Nd:YAG laser incorporating an unstable resonator

Introduction: For approximately the last eight years the Laser Section of the National Physical Research Laboratory (NPRL) has been interested in inter alia, pulsed solid-state lasers and in particular, Nd:YAG. Investigations of various resonator types were undertaken with a view to the improvement of the laser parameters such as output energy, pulse width, beam quality and sensitivity to mirror misalignment. In 1980 a Nd: YAG laser employing a rotating prism Q-switch was constructed (Preussler (1980)). It involves rotating one of the two cavity reflectors so that they are parallel for only a brief instant in time. Typically the prism must rotate at a speed of 20 000 r.p.m. to ensure a single pulse output. Such lasers suffer from the tendency to emit multiple pulses, they are very noisy and they require frequent maintenance because of the short lifetime of the bearings. A resonator employing conventional curved mirrors and an electro-optical Q-switch was constructed in 1980 (Robertson & Preussler (1982)). In 1981 an electro-optically Q-swi tched laser making use of a crossed Porro-prism resonator was investigated due to its relative insensitivity to misalignment of the reflectors compared with the conventional mirror resonator (Nortier (1981)). Improvements in terms of output power, beam divergence and beam quality can be achieved by making use of a so-called unstable resonator. Such a laser has been investigated and is reported on in this study. Chapter 2 provides some background into laser theory and operation while chapter 3 deals with the theory of the unstable resonator. Chapter 4 provides details of the experimental equipment and techniques used in the work and chapter 5 discusses the evaluation of the project and results obtained

The mental health of NHS staff during the COVID-19 pandemic:Two-wave Scottish cohort study

Background: Health and social care workers (HSCWs) are at risk of experiencing adverse mental health outcomes (e.g. higher levels of anxiety and depression) because of the COVID-19 pandemic. This can have a detrimental effect on quality of care, the national response to the pandemic and its aftermath. Aims: A longitudinal design provided follow-up evidence on the mental health (changes in prevalence of disease over time) of NHS staff working at a remote health board in Scotland during the COVID-19 pandemic, and investigated the determinants of mental health outcomes over time. Method: A two-wave longitudinal study was conducted from July to September 2020. Participants self-reported levels of depression (Patient Health Questionnaire-9), anxiety (Generalised Anxiety Disorder-7) and mental well-being (Warwick-Edinburgh Mental Well-being Scale) at baseline and 1.5 months later. Results: The analytic sample of 169 participants, working in community (43%) and hospital (44%) settings, reported substantial levels of depression and anxiety, and low mental well-being at baseline (depression, 30.8%; anxiety, 20.1%; well-being, 31.9%). Although mental health remained mostly constant over time, the proportion of participants meeting the threshold for anxiety increased to 27.2% at follow-up. Multivariable modelling indicated that working with, and disruption because of, COVID-19 were associated with adverse mental health changes over time. Conclusions: HSCWs working in a remote area with low COVID-19 prevalence reported substantial levels of anxiety and depression, similar to those working in areas with high COVID-19 prevalence. Efforts to support HSCW mental health must remain a priority, and should minimise the adverse effects of working with, and disruption caused by, the COVID-19 pandemic

Characterisation of the Wildlife Reservoir Community for Human and Animal Trypanosomiasis in the Luangwa Valley, Zambia

Animal and human trypanosomiasis are constraints to both animal and human health in Sub-Saharan Africa, but there is little recent evidence as to how these parasites circulate in natural hosts in natural ecosystems. A cross-sectional survey of trypanosome prevalence in 418 wildlife hosts was conducted in the Luangwa Valley, Zambia, from 2005 to 2007. The overall prevalence in all species was 13.9%. Infection was significantly more likely to be detected in waterbuck, lion, greater kudu and bushbuck, with a clear pattern apparent of the most important hosts for each trypanosome species. Human infective Trypanosoma brucei rhodesiense parasites were identified for the first time in African buffalo and T. brucei s.l. in leopard. Variation in infection is demonstrated at species level rather than at family or sub-family level. A number of significant risk factors are shown to interact to influence infection rates in wildlife including taxonomy, habitat and blood meal preference. Trypanosoma parasites circulate within a wide and diverse host community in this bio-diverse ecosystem. Consistent land use patterns over the last century have resulted in epidemiological stability, but this may be threatened by the recent influx of people and domesticated livestock into the mid-Luangwa Valley

Potential for non-combustible nicotine products to reduce socioeconomic inequalities in smoking: a systematic review and synthesis of best available evidence

While some experts have emphasised the potential for e-cigarettes to facilitate cessation among smokers with low socioeconomic status (SES), there is limited evidence of their likely equity impact. We assessed the potential for electronic cigarettes and other non-combustible nicotine-containing products (NCNPs) to reduce inequalities in smoking by systematically reviewing evidence on their use by SES in countries at stage IV of the cigarette epidemic

Targeted analysis of bioactive steroids and oxycholesterols : Method development and application

Peripheral steroids and oxycholesterols are important lipid compounds controlling various functions in the human body. Steroid analysis of biological samples is routinely employed in the clinical environment as an essential source of information on endocrine and metabolic disorders. It has been reported that stress related neurosteroids have been implicated in the development and prognoses of neurodegenerative disorders such as Alzheimer’s disease (AD). These compounds have been identified as possible biomarkers in the diagnosis of AD and other neurodegenerative disorders. Therefore, methods for the simultaneous analysis of steroids from the four major classes (estrogens, androgens, progestogens and corticosteroids) are vital in providing useful and more comprehensive data. Homeostasis of cholesterol in the brain is maintained primarily by metabolism to oxysterols, including oxycholesterols. These oxycholesterols act as a transport form of cholesterol as it readily navigates the blood-brain barrier. Oxycholesterols are generally more bioactive than cholesterol and is of interest in pathophysiology. Moreover, if their production in cells and tissues and/or their introduction with dietary animal fat are excessive, oxycholesterols could indeed contribute to the pathogenesis of various disease processes. The first study in this thesis focuses on a novel supercritical fluid chromatography–tandem mass spectrometry method for targeted analysis of eighteen peripheral steroids. The method is simple and fast. It has sufficient sensitivity for quantification of 18 different steroids in small volume human plasma. Therefore, this novel method can be applied for screening many steroids within 5 minutes providing the possibility to use for routine healthcare practice. The second study involves the quantification of three adrenal steroids in plasma from domesticated White Leghorn (WL) chickens and Red Junglefowl (RJF) birds. The domestication effects on stress induced steroid secretion and adrenal gene expression in chickens are evaluated. The third study focuses on determination of more than ten oxycholesterols in biological samples with a gas chromatography–mass spectrometry method and a supercritical fluid–tandem mass spectrometry method

Mass spectrometry based analysis of endogenous sterols and hormones

Bioanalytical applications using supercritical fluid chromatography (SFC) as analytical technique are of increasing interest. In essence, bioanalysis involves measurement of bioactive or endogenous compounds in biological matrices. SFC has emerged as an excellent choice for bioanalytical analysis, attributable to its speed, selectivity and efficiency compared with high performance liquid chromatography. Moreover, coupling of SFC with mass spectrometry (MS) provides the additional benefits of specificity and sensitivity. The aim of this thesis was to exploit these features by developing methods for the analysis of endogenous steroids, cholesterol oxidation products (COPs) and thyroid hormones (THs) by using ultra-performance supercritical fluid chromatography–tandem mass spectrometry (UPSFC–MS/MS) as analytical technique. Endogenous steroids control many physiological processes, including reproduction, maturation, gene expression and neurological functions in humans and animals. In the first study, three steroids were measured in domesticated White Leghorn (WL) chickens and ancestral Red Junglefowl (RJF) birds. Restraining stress caused a significantly larger increase in corticosterone levels in RJF than in WL, indicating a blunted hypothalamic–pituitary–adrenal (HPA) axis activity in domesticated chickens. The second study was a continuation of the first study and corticosterone levels from the F12 generation of an intercross between WL and RJF birds were measured before and after physical restraint stress. The expression levels of the glucocorticoid receptor (GR) in the hypothalamus and several genes in the adrenal glands were correlated with the post-stress levels of corticosterone in plasma. In the third study, the measurement of steroids was extended to assess more endogenous steroids from the four major classes, i.e. estrogens, androgens, progestogens and corticosterone. Endogenous COPs are of interest in pathophysiology. COPs are more readily disposed by cells than cholesterol. Therefore, cholesterol is oxidised to the more polar COPs and are generally more bioactive than cholesterol. Moreover, if their production in cells and tissues and/or their introduction with dietary animal fat are excessive, COPs could indeed contribute to the pathogenesis of various disease processes. Fourteen COPs were included in the fourth study and a novel method for their separation was developed. The last study in this thesis, involved the analysis of five THs. These hormones are vital for growth, developmental and metabolic processes of vertebrate life and play an important role in energy homeostasis. Measurements of circulating thyroid hormone levels are used in thyroid disorder diagnoses or treatment status monitoring. Two rapid methods for the separation of five THs were developed. In summary, the work in this thesis demonstrates the applicability of UPSFC–MS/MS as an analytical technique in bioanalysis of endogenous compounds

Targeted analysis of bioactive steroids and oxycholesterols : Method development and application

Peripheral steroids and oxycholesterols are important lipid compounds controlling various functions in the human body. Steroid analysis of biological samples is routinely employed in the clinical environment as an essential source of information on endocrine and metabolic disorders. It has been reported that stress related neurosteroids have been implicated in the development and prognoses of neurodegenerative disorders such as Alzheimer’s disease (AD). These compounds have been identified as possible biomarkers in the diagnosis of AD and other neurodegenerative disorders. Therefore, methods for the simultaneous analysis of steroids from the four major classes (estrogens, androgens, progestogens and corticosteroids) are vital in providing useful and more comprehensive data. Homeostasis of cholesterol in the brain is maintained primarily by metabolism to oxysterols, including oxycholesterols. These oxycholesterols act as a transport form of cholesterol as it readily navigates the blood-brain barrier. Oxycholesterols are generally more bioactive than cholesterol and is of interest in pathophysiology. Moreover, if their production in cells and tissues and/or their introduction with dietary animal fat are excessive, oxycholesterols could indeed contribute to the pathogenesis of various disease processes. The first study in this thesis focuses on a novel supercritical fluid chromatography–tandem mass spectrometry method for targeted analysis of eighteen peripheral steroids. The method is simple and fast. It has sufficient sensitivity for quantification of 18 different steroids in small volume human plasma. Therefore, this novel method can be applied for screening many steroids within 5 minutes providing the possibility to use for routine healthcare practice. The second study involves the quantification of three adrenal steroids in plasma from domesticated White Leghorn (WL) chickens and Red Junglefowl (RJF) birds. The domestication effects on stress induced steroid secretion and adrenal gene expression in chickens are evaluated. The third study focuses on determination of more than ten oxycholesterols in biological samples with a gas chromatography–mass spectrometry method and a supercritical fluid–tandem mass spectrometry method

The development of direct infusion mass spectrometry method for analysis of small metabolites in urine

Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: This study focused on the development of an analytical method whereby creatinine, creatine and caffeine could be determined quantitatively. Urine is the preferred body fluid for the analysis of metabolites that the body excretes after administration of medicinal and illicit drugs. The detection of these metabolites depends on the volume of water the patient has drunk or, in criminal cases, the amount of water the suspect may deliberately add to their urine to dilute it. Creatinine, whose concentration in urine has been found to correlate with muscle mass, is chosen as an endogenous control substance against which the metabolite concentration is compared. While high performance liquid chromatography with ultraviolet detection (HPLC–UV) is commonly selected for the analysis, the quality of chromatography is affected by the fact that creatinine, being highly polar, is not retained in the reversed-phase columns. Furthermore, urine contains many polar substances that elute with the solvent front along with creatinine, thereby grossly affecting HPLC measurements. Hydrophilic interaction chromatography (HILIC) is a good alternative, although these methods generally require extensive sample preparation. Direct infusion electrospray ionization mass spectrometry (DI–ESI–MS) is ideally suited to highly polar compounds and was selected for this work. Pneumatically assisted ESI is preferred above the standard ionization method of atmospheric pressure chemical ionization (APCI) since pneumatically assisted ESI disperses the solution into ion-containing aerosol droplets which do not promote online conversion of creatinine to creatine. The objective of this study was to develop a simple and sensitive DI–ESI–MS method for the determination of various compounds in urine with creatinine as analytical reference compound and internal standard (IS). The analytical method development includes addition of 1-methyl-3-phenylpropylamine as a primary IS to standard solutions as well as to urine samples, followed by direct infusion of the sample into a mass spectrometer to determine the absolute concentrations of creatinine, creatine and caffeine. After appropriate instrument conditions were established, linear graphs of analyte-IS signal intensity ratios were obtained. The ratio of the concentration of the analyte (drug or metabolite) to that of creatinine (as IS) may be used to determine analyte concentration in artificial samples and/or urine. This method is not affected by change in fluid volume or adulteration of urine samples because the analyte-to-creatinine ratio remains unchanged. As part of this study, the developed DI–ESI–MS method was compared with an LC–UV–MS method developed for this purpose.AFRIKAANSE OPSOMMING: Hierdie studie fokus op die ontwikkeling van ‘n analitiese metode waardeur kreatinien, kreatien en kaffeïen kwantitatief bepaal kan word. Uriene is die voorkeur liggaamsvloeistof vir die analise van metaboliete wat deur die liggaam, na administrasie van mediese en onwettige middels, uitgeskei word. Die deteksie van hierdie metaboliete hang van die volume water af wat die pasiënt gedrink het, of in strafbare gevalle, die hoeveelheid water wat verdagtes met opset by hul uriene gevoeg het ten einde dit te verdun. Daar is bevind dat die konsentrasie van kreatinien in uriene met spiermassa korreleer, derhalwe is kreatinien as ‘n interne kontrolemiddel gekies waarmee die metaboliet-konsentrasie vergelyk kan word. Hoë-druk vloeistofchromatografie met ultravioletdeteksie (HPLC–UV) word algemeen vir die analise van kreatinien ingespan, maar die gehalte van die chromatografie word deur die hoogs polêre aard van kreatinien beïnvloed en het swak retensie in omgekeerde-fasekolomme tot gevolg. Bowendien, uriene bevat groot hoeveelhede polêre middels wat saam met kreatinien in die oplosmiddelfront elueer en sodoende HPLC-bepalings uitermatig beïnvloed. Hidrofiliese interaksiechromatografie (HILIC) is ‘n goeie alternatief, ofskoon omvangryke monster-voorbereidings algemeen vereis word. Direkte inspuitelektrosproei-ionisasiemassaspektrometrie (DI–ESI–MS) is ideaal geskik vir hoogs polêre stowwe en is vir hierdie studie gekies. Pneumatiese hulp-ESI word bo die standaard ionisasie-metode van lugdruk chemiese ionisasie (APCI) verkies weens pneumatiese hulp-ESI se vermoë om die oplosmiddel in aërosoldruppels wat ione bevat, te versprei – sonder die aanlynomskakeling van kreatinien na kreatien. Die doel van hierdie studie was om ‘n eenvoudige en sensitiewe DI–ESI–MS-metode te ontwikkel wat verskeie stowwe in uriene kan bepaal deur kreatinien as analitiese verwysingsmiddel en interne standaard (IS) vir die opstelling van ‘n IS-kalibrasiekurwe te gebruik. Die analitiese metode-ontwikkeling sluit die gebruik van 1-metiel-3-fenielpropielamien as primêre IS in. Die IS word tot standaard oplossings en urienemonsters gevoeg, gevolg deur direkte inspuiting van die monster in ‘n massaspektrometer om die absolute konsentrasies van kreatinien, kreatien en kaffeïen te bepaal. Lineêre kurwes van die seinintensiteitsverhouding van analiet tot IS is verkry na gepaste instrumentkondisies vasgestel is. Die verhouding van konsentrasie van die analiet (middel of metaboliet) tot dié van kreatinien (as IS) mag gebruik word om die analietkonsentrasie in die standaard oplossings en/of urienemonster te bepaal. Die metode word nie deur veranderinge in die vloeistofvolume of verwatering van urienemonsters beïnvloed nie, weens die analiet-tot-kreatinienverhouding wat onveranderd bly. ‘n LC–UV–MS-metode is voorts ontwikkel om die ontwikkelde DI–ESI–MS-metode se data te vergelyk

A Stereophotogrammic system to position patients for Proton Therapy

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