title: Simultaneous estimation of chlorophyll a and lipid contents in microalgae by three-color analysis

authors: Su, Chia-Hung

subjects: microalgae

abstract: A method of rapid determination of chlorophyll a and lipid contents of microalgae based on colorimetric analysis of the digital images of the microalgae is proposed. The color variation of microalgae during cultivation is evaluated by the brightness of the three primary colors (red, green, and blue). The brightness values of the three primary colors are modeled as two linear correlation functions (RGB model) for microalgal chlorophyll a and lipid contents, respectively. The chlorophyll a and lipid contents predicted by the proposed model are compared with that determined by the standard methods. The good agreement of the model predictions with experimental results is demonstrated with a squared correlation coefficient (R2) of 0.99 for chlorophyll a and lipid. The reliability of the RGB model was verified in real cultivations of the microalgae in a photobioreactor. Growth dynamics, contents of chlorophyll a and lipid corresponded very well with previously reported studies.

text: Simultaneous estimation of chlorophyll a and lipid contents in microalgae by three-color analysis A method of rapid determination of chlorophyll a and lipid contents of microalgae based on colorimetric analysis of the digital images of the microalgae is proposed. The color variation of microalgae during cultivation is evaluated by the brightness of the three primary colors (red, green, and blue). The brightness values of the three primary colors are modeled as two linear correlation functions (RGB model) for microalgal chlorophyll a and lipid contents, respectively. The chlorophyll a and lipid contents predicted by the proposed model are compared with that determined by the standard methods. The good agreement of the model predictions with experimental results is demonstrated with a squared correlation coefficient (R2) of 0.99 for chlorophyll a and lipid. The reliability of the RGB model was verified in real cultivations of the microalgae in a photobioreactor. Growth dynamics, contents of chlorophyll a and lipid corresponded very well with previously reported studies.

year: 2008

title: Blu-ray cytometer

authors: Albugami, Naser

abstract: The flow cytometers are one of the most powerful devices used to measure the properties of individual particles passing through a sensing region. In this thesis, a low cost cytometer using a Blu-ray pickup is analysed and further developed. This includes the characterisation of the existing system and its performance as well as the evaluation of count rate for different flow rates and focuses. Based on that, the best parameters for measurement conditions have been determined. The system was set up for forward scatter as well as for fluorescence, both were to be measured at the same time and it was found that both could be recorded and counted. In addition, it was found that fluorescing particles can give a fluorescent count as well as scatter count and it was noticed that different sizes of non-fluorescent particles can produce scatter count. The count rate for a mixture of fluorescent and non-fluorescent particles was measured. This required the installation of two different amplifiers (for fluorescent and non-fluorescent particles) and building a new LabView program containing two channels.

In a later part of the thesis, the system was improved to progress towards a setup of avalanche photodiode as detector for forward scattering as well as fluorescence. This gives a very good counting accuracy of 90% at speed of 10μl/s. However, this counting accuracy drops to 80% at speed of 1μl/s when mixing fluorescent and non-fluorescent particles. The counting accuracy is the ratio (in percent) of the measured count to the actual one. As a new detection approach, a beam stop was installed in front of the photo detector so scattered laser light from particles was detected instead of a reduction of laser intensity. This part of the project proves Mie theory which states that the the forward scattered light is in the forward direction. To double check this result, a beam pass was installed in front of the photo detector and the calculated percentage of counting accuracy was very close to the one without a beam stop. It was also checked that the system was capable of detection fluorescent particle after the installation of a high bass filter which passes fluorescent wavelength signals (green) and blocks the blue ray signals. Finally, it was found that this system is able to detect small size particles, such as 1μm particles and to distinguish between 1μm and 10μm particles.

text: Blu-ray cytometer The flow cytometers are one of the most powerful devices used to measure the properties of individual particles passing through a sensing region. In this thesis, a low cost cytometer using a Blu-ray pickup is analysed and further developed. This includes the characterisation of the existing system and its performance as well as the evaluation of count rate for different flow rates and focuses. Based on that, the best parameters for measurement conditions have been determined. The system was set up for forward scatter as well as for fluorescence, both were to be measured at the same time and it was found that both could be recorded and counted. In addition, it was found that fluorescing particles can give a fluorescent count as well as scatter count and it was noticed that different sizes of non-fluorescent particles can produce scatter count. The count rate for a mixture of fluorescent and non-fluorescent particles was measured. This required the installation of two different amplifiers (for fluorescent and non-fluorescent particles) and building a new LabView program containing two channels.

In a later part of the thesis, the system was improved to progress towards a setup of avalanche photodiode as detector for forward scattering as well as fluorescence. This gives a very good counting accuracy of 90% at speed of 10μl/s. However, this counting accuracy drops to 80% at speed of 1μl/s when mixing fluorescent and non-fluorescent particles. The counting accuracy is the ratio (in percent) of the measured count to the actual one. As a new detection approach, a beam stop was installed in front of the photo detector so scattered laser light from particles was detected instead of a reduction of laser intensity. This part of the project proves Mie theory which states that the the forward scattered light is in the forward direction. To double check this result, a beam pass was installed in front of the photo detector and the calculated percentage of counting accuracy was very close to the one without a beam stop. It was also checked that the system was capable of detection fluorescent particle after the installation of a high bass filter which passes fluorescent wavelength signals (green) and blocks the blue ray signals. Finally, it was found that this system is able to detect small size particles, such as 1μm particles and to distinguish between 1μm and 10μm particles.

year: 2012

title: "Takahi ngā takahanga o ngā tūpuna" - Tramp the pathways of our ancestors

authors: Williams, Taniwha

subjects: Māori health and wellbeing

abstract: The rise of reconnecting to holistic approaches to health to improve wellbeing outcomes for Māori has become increasingly prominent in recent years. Such developments have highlighted the need to introduce traditional Māori concepts, values and practices within whānau, hapū and iwi as vehicles for promoting and improving Māori health. This research had two objectives. Firstly, it aimed to explore the process of reclaiming mātauranga Māori (Māori knowledge systems) with my whānau who had limited access to te ao Māori (the Māori world). The second objective sought to explore the experiences of my whānau reconnecting with te reo me ōna tikanga (Māori language and culture). Using the Whiti Te Rā as a guide informed the design and structure of the wānanga (workshops). The Whiti Te Rā is a therapeutic model designed to improve health and wellbeing outcomes for Māori by developing and enhancing a cultural identity. Central to this model are six Māori customary practices and values that provide pathways to wellbeing and flourishing mauri. These dimensions also have synergies with other models of health – Te Whare Tapa Whā, Te Wheke. Four tāne (men) from my whānau took part in this research. We used the Pūrākau Method to record, explore, and analyse the narratives that emerged following each wānanga. The key findings from this research included connection to history, whakapapa and wairua; connection to pepeha and cultural practices; connection to self as a Māori; connection through whanaungatanga; and connection to taiao (the environment). This study showed that Māori models of health and wellbeing are consistent in demonstrating their effectiveness in connecting Māori to their language and culture. Despite the impact of colonisation, reconnection to customary practices and values was meaningful and valuable to my whānau. Future research is needed to revitalise, regenerate and reclaim a thriving Māori identity.

text: "Takahi ngā takahanga o ngā tūpuna" - Tramp the pathways of our ancestors The rise of reconnecting to holistic approaches to health to improve wellbeing outcomes for Māori has become increasingly prominent in recent years. Such developments have highlighted the need to introduce traditional Māori concepts, values and practices within whānau, hapū and iwi as vehicles for promoting and improving Māori health. This research had two objectives. Firstly, it aimed to explore the process of reclaiming mātauranga Māori (Māori knowledge systems) with my whānau who had limited access to te ao Māori (the Māori world). The second objective sought to explore the experiences of my whānau reconnecting with te reo me ōna tikanga (Māori language and culture). Using the Whiti Te Rā as a guide informed the design and structure of the wānanga (workshops). The Whiti Te Rā is a therapeutic model designed to improve health and wellbeing outcomes for Māori by developing and enhancing a cultural identity. Central to this model are six Māori customary practices and values that provide pathways to wellbeing and flourishing mauri. These dimensions also have synergies with other models of health – Te Whare Tapa Whā, Te Wheke. Four tāne (men) from my whānau took part in this research. We used the Pūrākau Method to record, explore, and analyse the narratives that emerged following each wānanga. The key findings from this research included connection to history, whakapapa and wairua; connection to pepeha and cultural practices; connection to self as a Māori; connection through whanaungatanga; and connection to taiao (the environment). This study showed that Māori models of health and wellbeing are consistent in demonstrating their effectiveness in connecting Māori to their language and culture. Despite the impact of colonisation, reconnection to customary practices and values was meaningful and valuable to my whānau. Future research is needed to revitalise, regenerate and reclaim a thriving Māori identity.

year: 2024