45 research outputs found
A simple spectrophotometric method for determination of thiamine (vitamin B1) in pharmaceuticals
A simple spectrophotometric method has been described for the determination of thiamine. The method is based on the precipitation of sulphur as barium sulphate using barium chloride after oxidation of thiamine by sodium hydroxide and hydrogen peroxide. Beer's law was obeyed over the concentration range from 2-32 µg/mL thiamine. The average of standard deviation was 1.18×10-2; standard error, 5.20×10-3; relative standard deviation, 0.51%; relative standard error, 5.40×10-3; 95% coefficient, 1.48×10-2; the limit of detection, 0.41 µg/mL; the limit of quantification, 1.38 µg/mL and recovery, 100.03% thiamine. Finally, the developed method was applied to the determination of thiamine in pharmaceutical formulations
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Does Saudi corporate governance attain International standards using the UK best practice as an exemplar
The concept of corporate governance has been recognised as one of the most important legal, business and financial management concepts in recent times. Corporate governance is a tool that aims to apply principles such as fairness between shareholders, punishing and preventing wrongdoing, helping society and encouraging full disclosure of company information. This will help to reinforce the stability in the financial market, restore the confidence of investors and attract new and foreign investment. The primary objective of this research is to determine whether the Saudi Arabia corporate governance framework is in line with international standards and to examine if there are any need and willingness for reform. The motivation for selecting the United Kingdom as a benchmark for comparison was inspired by its reputation in upholding high corporate governance standards. The research seeks to outline possible recommendations to add to the Saudi corporate governance regulation, so it can achieve the highest possible standards of corporate governance. A starting point would be the analysis of the UK Companies Act and the UK Corporate Governance Code to determine what can be learned from the experience in the UK to help advance the situation in Saudi Arabia. The research will focus on several key issues, namely, directors’ duties, current boardroom practices and gender diversity in Saudi corporate boards. The research will also take into account the possibility of implementing any suggested reforms in adherence to Sharia principles. The research found that the Saudi corporate governance reflects certain elements of good international corporate governance standards. However, the research revealed major shortcoming in Saudi directors’ duties and gender diversity and that these need reform to attain international standards. Taken together, the research findings suggest that Saudi Arabia will benefit from adopting some of the best practices from the UK to reinforce its attractiveness to foreign investment
Lutein and zeaxanthin attenuates VEGF-induced neovascularisation in human retinal microvascular endothelial cells through a Nox4-dependent pathway
Age-related macular degeneration (AMD) and proliferative diabetic retinopathy (DR) are two of the most common and severe causes of vision loss in the population. Both conditions are associated with excessive levels of vascular endothelial growth factor (VEGF) in the eye which results in an increase in the formation of new blood vessels through a process called neovascularisation. As such, anti-VEGF therapies are currently utilised as a treatment for patients with AMD however they are associated with painful administration of injections and potential degeneration of healthy endothelium. There is therefore growing interest in alternate treatment options to reduce neovascularisation in the eye. The use of carotenoids, lutein (L) and zeaxanthin (Z), has been shown to improve vision loss parameters in patients with AMD, however the underlying mechanisms are not well-understood. We studied the impact of these compounds on neovascularisation processes using an in vitro cell model of the retinal microvascular endothelium. Our findings show that L and Z reduced VEGF-induced tube formation whilst, in combination (5:1 ratio), the compounds significantly blocked VEGF-induced neovascularisation. The carotenoids, individually and in combination, reduced VEGF-induced oxidative stress concomitant with increased activity of the NADPH oxidase, Nox4. We further demonstrated that the Nox4 inhibitor, GLX7013114, attenuated the protective effect of L and Z. Taken together, these findings indicate the protective effect of the carotenoids, L and Z, in reducing VEGF-mediated neovascularisation via a Nox4-dependent pathway. These studies implicate the potential for these compounds to be used as a therapeutic approach for patients suffering from AMD and proliferative DR