Establishing the cardiothoracic ratio using chest radiographs in an indigenous Ghanaian population: a simple tool for cardiomegaly screening

Background: Cardiothoracic ratio is a simple and cheap tool in the estimation of heart size. It is a useful index of cardiac size evaluation, and a value of 50% is generally considered to indicate the upper limit of normal.Study Objective: This study is to ascertain the normal mean value in cardiothoracic ratio of Ghanaians using chest radiography to serve as baseline for screening for cardiomegaly.Methodology: Standard postero-anterior radiographs of the -clients/patients were used in the study. The cardiothoracic ratio (CTR) was obtained by dividing the transverse cardiac diameter [sum of the horizontal distances from the right and left lateral-most margins of the heart to the midline (spinous processes of the vertebral bodies)] by the maximum internal thoracic diameter. Systematic sampling with appropriate inclusion and exclusion criteria were used to obtain a sample size of 1989.Results: The mean transverse cardiac diameter and cardiothoracic ratio increased with age. The transverse thoracic diameter increased with age until the sixth decade when it reduced with age. The mean CTR increased gradually with age with females having greater values than males. The mean CTR of the study population were 0.459, 0.467 and 0.452 for the general population, females and males respectively.Conclusion: This study has been able to establish 0.459 as the mean CTR values for Ghanaians. It has also shown the relationship between age and clients /patient’s cardiothoracic ratio which compares favourably with findings of a similar study in Nigeria, a neighbouring country in the West African sub region with similar ethnic and social structure.Keywords: Radiography, Indigenous Ghanaian, cardiomegaly, cardiothoracic ratio, Screenin

Bioreactor for microalgal cultivation systems: strategy and development

Microalgae are important natural resources that can provide food, medicine, energy and various bioproducts for nutraceutical, cosmeceutical and aquaculture industries. Their production rates are superior compared to those of terrestrial crops. However, microalgae biomass production on a large scale is still a challenging problem in terms of economic and ecological viability. Microalgal cultivation system should be designed to maximize production with the least cost. Energy efficient approaches of using light, dynamic mixing to maximize use of carbon dioxide (CO2) and nutrients and selection of highly productive species are the main considerations in designing an efficient photobioreactor. In general, optimized culture conditions and biological responses are the two overarching attributes to be considered for photobioreactor design strategies. Thus, fundamental aspects of microalgae growth, such as availability of suitable light, CO2 and nutrients to each growing cell, suitable environmental parameters (including temperature and pH) and efficient removal of oxygen which otherwise would negatively impact the algal growth, should be integrated into the photobioreactor design and function. Innovations should be strategized to fully exploit the wastewaters, flue-gas, waves or solar energy to drive large outdoor microalgae cultivation systems. Cultured species should be carefully selected to match the most suitable growth parameters in different reactor systems. Factors that would decrease production such as photoinhibition, self-shading and phosphate flocculation should be nullified using appropriate technical approaches such as flashing light innovation, selective light spectrum, light-CO2 synergy and mixing dynamics. Use of predictive mathematical modelling and adoption of new technologies in novel photobioreactor design will not only increase the photosynthetic and growth rates but will also enhance the quality of microalgae composition. Optimizing the use of natural resources and industrial wastes that would otherwise harm the environment should be given emphasis in strategizing the photobioreactor mass production. To date, more research and innovation are needed since scalability and economics of microalgae cultivation using photobioreactors remain the challenges to be overcome for large-scale microalgae production