Vitamin and mineral deficiencies in the developed world and their effect on the eye and vision

Vitamin and mineral deficiencies are common in developing countries, but also occur in developed countries. We review micronutrient deficiencies for the major vitamins A, cobalamin (B-12), biotin (vitamin H), vitamins C and E, as well as the minerals iron, and zinc, in the developed world, in terms of their relationship to systemic health and any resulting ocular disease and/or visual dysfunction. A knowledge of these effects is important as individuals with consequent poor ocular health and reduced visual function may present for ophthalmic care.

Ocular and systemic vascular function in human ageing

The importance of vascular risk factors in various age-related pathologies has been extensively researched. Nevertheless, the haemodynamic disturbance occurring in various ocular and systemic vascular beds to impact upon ocular function remained largely unknown. The purpose of the following studies was to explore the presence and impact of both ocular and systemic vascular dysregulation as well as biochemical vascular risk factors in healthy elderly individuals and patients with age-related macular degeneration. Furthermore, the possible role was played by circulatory oxidative stress and its relationship with endothelial dysfunction at both ocular and systemic levels has also been investigated. There were four principal sections to the present work: 1. To assess the relationship between ocular and systemic anti-oxidative defence in healthy individuals The principal findings of this work were: -It has been shown that MPOD significantly and positively related with circulatory GSH levels. 2. To investigate macro- and microcirculation and oxidative stress in early AMD patients without overt systemic disease The principal findings of this work were: -AMD patients exhibit abnormal macrocirculation compared to the controls. -Blood GSSG level was significantly higher in early AMD patients than controls. -AMD patients showed abnormal microcirculation at retinal level compared. -In early AMD patients, retinal venous RT positively correlated with blood GSSG levels. 3. To assess the relationship between ocular vascular function and circulatory markers of endothelial dysfunction and CVD risk The principal findings of this work were: -Age had a positive effect on ET-1, vWF and slope of retinal arterial constriction in otherwise healthy individuals. -Even in otherwise healthy individuals, retinal arterial vascular function showed a significant correlation with circulatory markers of endothelial dysfunction and CVD risk. 4. To assess age-related changes in ANS and vascular function, and their relationship to retinal vascular function parameters The principal findings of this work were: -Elderly individuals demonstrated abnormal circadian changes of PSNS activity compared to middle-aged group. -Elderly groups showed higher ET-1 and vWF level as well as C-IMT and AIx, and also impaired retinal vascular function compared to the middle-aged group. -In the elderly group, impaired retinal vascular function significantly correlated with the dysregulation of PSNS activity.

Effect of support and cultural intelligence on the adjustment and performance of expatriates and their family members in Malaysia

Theory suggests that people fear the unknown and no matter how experienced one is, the feelings of anxiety and uncertainty, if not managed well would affect how we view ourselves and how others view us. Hence, it is in human nature to engage in activities to help decipher behaviours that seem contrary to their beliefs and hinder the smooth-flowing of their work and daily activities. Building on these arguments, this research investigates the two types of support that are provided by multinational corporations (MNCs) and host country nationals (HCNs) to the expatriates and their family members whilst on international assignments in Malaysia as antecedents to their adjustment and performance in the host country. To complement the support provided, cultural intelligence (CQ) is investigated to explain the influence of cultural elements in facilitating adjustment and performance of the relocating families, especially to socially integrate into the host country. This research aims to investigate the influence of support and CQ on the adjustment and performance of expatriates in Malaysia. Path analyses are used to test the hypothesised relationships. The findings substantiate the pivotal roles that MNCs and HCNs play in helping the expatriates and their families acclimatise to the host country. This corroborates the norm of reciprocity where assistance or support rendered especially at the times when they were crucially needed would be reciprocated with positive behaviour deemed of equal value. Additionally, CQ is significantly positive in enhancing adjustment to the host country, which highlights the vital role that cultural awareness and knowledge play in enhancing effective intercultural communication and better execution of contextual performance. The research highlights the interdependence of the expatriates? multiple stakeholders (i.e. MNCs, HCNs, family members) in supporting the expatriates whilst on assignments. Finally, the findings reveal that the expatriate families do influence how the locals view the families and would be a great asset in initiating future communication between the expatriates and HCNs. The research contributes to the fields of intercultural adjustment and communication and also has key messages for policy makers.

The effect of antifoams upon recombinant protein production in yeast

Foaming during fermentation reduces the efficiency of the process leading to increased costs and reduced productivity. Foaming can be overcome by the use of chemical antifoaming agents, however their influence upon the growth of organisms and protein yield is poorly understood. The objective of this work was to evaluate the effects of different antifoams on recombinant protein production. Antifoam A, Antifoam C, J673A, P2000 and SB2121 were tested at different concentrations for their effect on the growth characteristics of Pichia pastoris producing GFP, EPO and A2aR and the yield of protein in shake flasks over 48 h. All antifoams tested increased the total GFP in the shake flasks compared to controls, at higher concentrations than would normally be used for defoaming purposes. The highest yield was achieved by adding 1 % P2000 which nearly doubled the total yield followed by 1 % SB2121, 1 % J673A, 0.6 % Antifoam A and lastly 0.8 % Antifoam C. The antifoams had a detrimental effect upon the production of EPO and A2aR in shake flasks, suggesting that their effects may be protein specific. The mechanisms of action of the antifoams was investigated and suggested that although the volumetric mass oxygen transfer coefficient (kLa) was influenced by the agents, their effect upon the concentration of dissolved oxygen did not contribute to the changes in growth or recombinant protein yield. Findings in small scale also suggested that antifoams of different compositions such as silicone polymers and alcoxylated fatty acid esters may influence growth characteristics of host organisms and the ability of the cells to secrete recombinant protein, indirectly affecting the protein yield. Upon scale-up, the concentration effects of the antifoams upon GFP yield in bioreactors was reversed, with lower concentrations producing a higher yield. These data suggest that antifoam can affect cells in a multifactorial manner and highlights the importance of screening for optimum antifoam types and concentrations for each bioprocesses.

An investigation of the emerging system of host government participation in the international oil industry with particular reference to Libyan participation arrangements

This study has been conceived with the primary objective of identifying and evaluating the financial aspects of the transformation in country/company relations of the international oil industry from the traditional concessionary system to the system of governmental participation in the ownership and operation of oil concessions. The emphasis of the inquiry was placed on assembling a case study of the oil exploitation arrangements of Libya. Through a comprehensive review of the literature, the sociopolitical factors surrounding the international oil business were identified and examined in an attempt to see their influence on contractual arrangements and particularly to gauge the impact of any induced contractual changes on the revenue benefit accruing to the host country from its oil operations. Some comparative analyses were made in the study to examine the viability of the Libyan participation deals both as an investment proposal and as a system of conducting oil activities in the country. The analysis was carried out in the light of specific hypotheses to assess the relative impact of the participation scheme in comparison with the alternative concessionary model on the net revenue resulting to the government from oil operations and the relative effect on the level of research and development within the industry. A discounted cash flow analysis was conducted to measure inputs and outputs of the comparative models and judge their revenue benefits. Then an empirical analysis was carried out to detect any significant behavioural changes in the exploration and development effort associated with the different oil exploitation systems. Results of the investigation of revenues support the argument that the mere introduction of the participation system has not resulted in a significant revenue benefit to the host government. Though there has been a significant increase in government revenue, associated with the period following the emergence of the participation agreements, this increase was mainly due to socio-economic factors other than the participation scheme. At the same time the empirical results have shown an association of the participation scheme with a decline of the oil industry's research and development efforts.

Mediators of gram-positive septic shock

Septic shock can occur as a result of Gram-negative or Gram-positive infection and involves a complex interaction between bacterial factors and the host immune system producing a systemic inflammatory state that may progress to multiple organ failure and death. Gram-positive bacteria are increasingly becoming more prevalent especially Staphylococcus epidermidis in association with indwelling devices. Lipopolysaccaride (LPS) is the key Gram-negative component involved in this process, but it is not clear which components of Gram-positive bacteria are responsible for progression of this often fatal disease. The aim of this thesis was to investigate the effect of bacterial components on the immune systems. Lipid S, a short chain form of lipoteichoic acid (LTA) found to be excreted from bacteria during growth in culture medium was examined along with other Gram-positive cell wall components: LTA, peptidoglycan (PG) and wall teichoic acids (WTA) and LPS from Gram-negative bacteria. Lipid S, LTA, PG and LPS but not WTA all stimulated murine macrophages and cell lines to produce significant amounts of NO, TNF-a, IL-6 and IL-1 and would induce fever and tissue damage seen in inflammatory diseases. Lipid S proved to be the most potent out of the Gram-positive samples tested. IgG antibodies in patients serum were found to bind to and cross react with lipid S and LTA. Anti-inflammatory antibiotics, platelet activating factor (PAF), PAF receptor antagonists and monoclonal antibodies (mAbs) directed to LTA, CD14 and toll-like receptors were utilised to modulate cytokine and NO production. In cell culture the anti-LTA and the anti-CD14 mAbs failed to markedly attenuate the production of NO, TNF-a, IL-6 or IL-1, the anti-TLR4 antibody did greatly inhibit the ability of LPS to stimulate cytokine production but not lipid S. The tetracyclines proved to be the most effective compounds, many were active at low concentrations and showed efficacy to inhibit both lipid S and LPS stimulated macrophages to produce NO.

Autonomic dysfunction and systemic oxidative stress associated with glaucomatous optic neuropathy

There were four principal sections to the work: 1. Investigation of ocular and systemic vascular risk factors in POAG. The principal findings of this work were: a). Glaucoma patients exhibit an anticipatory reaction to the physical stress, similar to subjects at risk for cardiovascular diseases; a blunted BP response and a reduction in ONH blood flow in response to cold provocation was also recorded. b). Silent myocardial ischaemic episodes occurred during peaks in systemic BP and HR. c). Independent of a positive history for cardiovascular diseases, patients suffering from POAG demonstrate a blunt circadian rhythm of the ANS. 2. Assessment of the relationship between vascular and systemic vascular risk factors in GON. The principal findings of this work were: a). POAG patients demonstrate a high sympathetic tonus over a 24-h period. b). POAG patients with lower OBF demonstrate both 24-h systemic BP and HRV abnormalities. c). OBF alterations observed in some glaucoma patients could be either primary or secondary to systemic haemodynamic disturbances and not a consequence of ONH damage. 3. Assessment of the level of systemic anti-oxidant defence in POAG patients. The principal finding of this work was: Patients suffering from POAG demonstrated significantly lower GSH and t-GSH levels than normal controls. 4. Investigation of the effect of treatment with latanoprost 0.005% on visual function and OBF. The findings of this work were: a). Treatment with latanoprost 0.005% resulted in a significant decrease in IOP and increase in OPP. VF damage progression has also been stopped. b). Treatment with latanoprost 0.005% resulted in a significant increase in the OBF parameters measured at the ONH and peripapillary retina levels. Finally, the importance of a clear protocol for managing new POAG cases is highlighted and a clinical conduit is proposed.

The effect of antifoam addition on protein production yields

Pichia pastoris is a widely used host for recombinant protein production. The foaming associated with culturing it on a large scale is commonly prevented by the addition of chemical antifoaming agents or "antifoams." Unexpectedly, the addition of a range of antifoams to both shake flask and bioreactor cultures of P. pastoris has been shown to alter the total yield of the recombinant protein being produced. Possible explanations for this are that the presence of the antifoam increases the total amount of protein being produced and secreted per cell or that it increases the density of the culture. Antifoaming agents may therefore have specific effects on the growth and yield characteristics of recombinant cultures, in addition to their primary action as de-foamers.

Using organoclay to promote morphology refinement and co-continuity in high-density polyethylene/polyamide 6 blends - Effect of filler content and polymer matrix composition

We investigate the gradual changes of the microstructure of two blends of high-density polyethylene (HDPE) and polyamide 6 (PA6) at opposite composition filled with increasing amounts of an organomodified clay. The filler locates preferentially inside the polyamide phase, bringing about radical alterations in the micron-scale arrangement of the polymer phases. When the host polyamide represents the major constituent, a sudden reduction of the average sizes of the polyethylene droplets was observed upon addition of even low amounts of organoclay. A morphology refinement was also noticed at low filler contents when the particles distributes inside the minor phase. In this case, however, keep increasing the organoclay content eventually results in a high degree of PA6 phase continuity. Rheological analyses reveal that the filler loading at which the polyamide assembles in a continuous network corresponds to the critical threshold for its rheological transition from a liquid- to a gel-like behaviour, which is indicative of the structuring of the filler inside the host PA6. On the basis of this finding, a schematic mechanism is proposed in which the role of the filler in driving the space arrangement of the polymer phases is discussed. Finally, we show that the synergism between the reinforcing action of the filler and its ability to affect the blend microstructure can be exploited in order to enhance relevant technological properties of the materials, such as their high temperature structural integrity.

The effect of corruption on FDI:a parametric and non-parametric analysis

This paper analyses the effect of corruption on Multinational Enterprises' (MNEs) incentives to undertake FDI in a particular country. We contribute to the existing literature by modelling the relationship between corruption and FDI using both parametric and non-parametric methods. We report that the impact of corruption on FDI stock is different for the different quantiles of the FDI stock distribution. This is a characteristic that could not be captured in previous studies which used only parametric methods. After controlling for the location selection process of MNEs and other host country characteristics, the result from both parametric and non-parametric analyses offer some support for the ‘helping-hand’ role of corruption.

Ageing effect on flicker-induced diameter changes in retinal microvessels of healthy individuals

Purpose: To compare flicker-induced retinal vessel diameter changes in varying age groups with low cardiovascular risk. Methods: Retinal vascular reactivity to flicker light was assessed by means of dynamic retinal vessel analysis in 57 participants aged 19-30 years, 75 participants aged 31-50 years and 62 participants aged 51-70 years participants. Other assessments included carotid intima-media thickness (c-IMT), augmentation index (AIx), blood pressure profiles, blood lipid metabolism markers and Framingham risk scores (FRS). Results: Retinal arterial dilation amplitude (DA) and postflicker percentage constriction (MC%) were significantly decreased in the oldest group compared to the middle-aged (p = 0.028; p = 0.021) and youngest group (p = 0.003; p = 0.026). The arterial constriction slope (SlopeAC) was also decreased in the oldest group compared to the youngest group (p = 0.027). On the venous side, MC% was decreased in the middle-aged and oldest groups in comparison with the youngest group (p = 0.015; p = 0.010, respectively). Additionally, men exhibited increased arterial DA (p = 0.007), and percentage dilation (MD%, p < 0.001) in comparison with women, but only in the youngest age group. Both AIx and c-IMT scores increased with age (both p < 0.001); however, no correlations were found between the observed differences in the measured retinal vascular function and systemic parameters. Conclusion: In individuals with low cardiovascular risk, there are age-related differences in flicker-induced retinal vessel diameter changes throughout the entire functional response curve for arteries and veins. Gender differences mainly affect the arterial dilatory phase and are only present in young individuals.

Are tumoral factors responsible for host tissue wasting in cancer cachexia?

Both cytokines and tumor factors have been implicated in tissue loss in cancercachexia. Loss of adipose tissue is most likely due to the tumor (and host) factorzinc-α2-glycoprotein because of its direct lipolytic effect, ability to sensitizeadipocytes to lipolytic stimuli and increased expression in cachexia. TNF-α andthe tumor factor proteolysis-inducing factor are the major contenders for skeletalmuscle at rophy; both increase protein degradat ion through theubiquitin-proteasome pathway and depres s protein synthesis throughphosphorylation of eukaryotic initiation factor 2α. However, while most studiesreport proteolysis-inducing factor levels to correlate with the appearance ofcachexia, there is some disagreement regarding a correlation between serumlevels of TNF-α and weight loss. Furthermore, only antagonists to proteolysisinducingfactor prevent muscle loss in cancer patients, suggesting that tumorfactors are the most important. © 2010 Future Medicine Ltd.

Children's perceptions of marital conflict, parent -child relations and anxiety in children: A proposed systemic model

This study tested a systemic model in which internalizing behaviors in a clinically-referred sample of children are predicted by children's perceptions of marital conflict in the context of three additional, well-researched, familial variables: parent-child relations, mother's emotional functioning, and children's perception of social support. After finding preliminary support for the model, its generalizability was tested in a combined sample of the clinically-referred group and a community-based group of elementary school children. ^ The clinical group consisted of 31 participants from a specialty clinic for children's anxiety disorders: 15 boys and 16 girls, aged 6 to 16, from both intact and divorced homes. Children's reports and mothers' reports of children's internalizing behaviors were submitted to separate analyses. Mothers' reports of children's internalizing behaviors were predicted only by mothers' emotional functioning. As hypothesized by the model, children's own reports of their internalizing behaviors were predicted significantly by children's perceptions of marital conflict. Parent-child relations, children's perception of social support, and one interaction term, children's perception of marital conflict x children's perception of parental rejection, contributed to the regression solution, while mother's emotional functioning failed to meet entry criterion. ^ The combined sample added 37 community-based children, 18 boys and 19 girls, aged 6 to 11, creating a total of 68 subjects. The model was replicated on the combined sample. ^ Findings of the study suggest child perceptions of marital conflict have a strong direct effect on child internalizing behaviors, accounting for 28% of the variance between marital conflict and child outcome in the clinical sample and 42% in the combined sample. In the past only about 10% of the variance in children's internalizing behaviors was explained by marital conflict. Importance implications are made for optimal assessment and specific treatment strategies for children and families experiencing marital conflict, especially for those at risk for anxiety disorders. ^

What does board capital really bring to the table? Exploring the effect of directors' human and social capital on effective governance during international expansion

What constitutes effective corporate governance? Which director characteristics render boards effective at positively influencing firm-level performance outcomes? This dissertation examines these questions by taking a multilevel, multidisciplinary approach to corporate governance. I explore the individual-, team-, and firm- level factors that enable directors to serve effectively as strategic resources during international expansion. I argue that directors' international experience improves their ability to serve as effective strategic consultants and resource providers to firms during the complex internationalization process. However, unlike prior research, which tends to assume that directors with the potential to provide important resources uniformly do so, I acknowledge contextual factors (i.e. board cohesiveness, strategic relevance of directors' experience) that affect their propensity to actually influence outcomes. I explore these issues in three essays: one review essay and two empirical essays.^ In the first empirical essay, I integrate resource dependence theory with insights from social-psychological research to explore the influence of board capital on firms' cross-border M&A performance. Using a sample of cross-border M&As completed by S&P 500 firms from 2004-2009, I find evidence that directors' depth of international experience is associated with superior pre-deal outcomes. This suggests that boards' deep, market-specific knowledge is valuable during the target selection phase. I further find that directors' breadth of international experience is associated with superior post-deal performance, suggesting that these directors' global mindset helps firms in the post-M&A integration phase. I also find that these relationships are positively moderated by board cohesiveness, measured by boards' internal social ties.^ In the second empirical essay, I explore the boundary conditions of international board capital by examining how the characteristics of firms' internationalization strategy moderate the relationship between board capital and firm performance. Using a panel of 377 S&P 500 firms observed from 2004-2011, I find that boards' depth of international experience and social capital are more important during early stages of internationalization, when firms tend to lack market knowledge and legitimacy in the host markets. On the other hand, I find that breadth of international experience has a stronger relationship with performance when firms' have higher scope of internationalization, when information-processing demands are higher.^

Are long gamma-ray bursts biased tracers of star formation? Clues from the host galaxies of the Swift/BAT6 complete sample of bright LGRBs II. Star formation rates and metallicities at z < 1

Aims. Long gamma-ray bursts (LGRBs) are associated with the deaths of massive stars and might therefore be a potentially powerful tool for tracing cosmic star formation. However, especially at low redshifts (z< 1.5) LGRBs seem to prefer particular types of environment. Our aim is to study the host galaxies of a complete sample of bright LGRBs to investigate the effect of the environment on GRB formation. Methods. We studied host galaxy spectra of the Swift/BAT6 complete sample of 14 z< 1 bright LGRBs. We used the detected nebular emission lines to measure the dust extinction, star formation rate (SFR), and nebular metallicity (Z) of the hosts and supplemented the data set with previously measured stellar masses M_*. The distributions of the obtained properties and their interrelations (e.g. mass-metallicity and SFR-M_* relations) are compared to samples of field star-forming galaxies. Results. We find that LGRB hosts at z< 1 have on average lower SFRs than if they were direct star formation tracers. By directly comparing metallicity distributions of LGRB hosts and star-forming galaxies, we find a good match between the two populations up to 12 +log (O/H)~8.4−8.5, after which the paucity of metal-rich LGRB hosts becomes apparent. The LGRB host galaxies of our complete sample are consistent with the mass-metallicity relation at similar mean redshift and stellar masses. The cutoff against high metallicities (and high masses) can explain the low SFR values of LGRB hosts. We find a hint of an increased incidence of starburst galaxies in the Swift/BAT6 z< 1 sample with respect to that of a field star-forming population. Given that the SFRs are low on average, the latter is ascribed to low stellar masses. Nevertheless, the limits on the completeness and metallicity availability of current surveys, coupled with the limited number of LGRB host galaxies, prevents us from investigating more quantitatively whether the starburst incidence is such as expected after taking into account the high-metallicity aversion of LGRB host galaxies.