Although infrared spectroscopy is a very common analytical tool in the chemical sciences, quantit... more Although infrared spectroscopy is a very common analytical tool in the chemical sciences, quantitative infrared spectroscopic studies of multi-component solutions (particularly on-line or in-line studies) have been hampered by the lack of a concise and robust numerical approach. Using an inert chemical species as internal standard, the usual absorbance ratio analysis is generalized into a mathematical form that converts typical absorbance measurement A into its renormalized absorbance Arenorm, with the latter directly relating to the absolute moles rather than the concentration of the constituents. The renormalized absorbance has a number of very important properties, including (1) insensitivity to path length changes due to variations in temperature or pressure of the Fourier transform infrared (FT-IR) cell and (2) insensitivity to solution volume changes arising from reaction, chemical transport, or thermodynamic conditions. The methodology is first applied to a simple model test ...
The band-target entropy minimization method (BTEM) and its variant methods excel at reconstructin... more The band-target entropy minimization method (BTEM) and its variant methods excel at reconstructing known/unknown pure spectra from mixtures without prior information. These mixtures may represent either non-reactive or even reactive systems. In this work, an unsupervised form of the entropy minimization curve resolution, namely, the multi-reconstruction entropy minimization method (MREM), is presented. MREM differs from BTEM by removing the need for band-targets and by introducing a multiple search routine to find multiple local entropy minima. This multiple search routine, which provides a rapid survey of spectral estimates, utilizes a localized form of Corona's simulated annealing method in the optimization. The objective functions and penalty functions of the BTEM type methods are essentially retained. Compared to BTEM type methods, MREM (1) searches for multiple local minima instead of a single global minimum and hence reconstructs many pure component spectra at once instead...
Background The colonial microalga Botryococcus braunii has been brought to people's attention... more Background The colonial microalga Botryococcus braunii has been brought to people's attention for its conspicuous ability to accumulate a variety of lipids including hydrocarbons. B. braunii strains are classified into 3 races based on the types of hydrocarbons. A and B races are known to accumulate high level of lipids. However, their extreme slow growth rate has impeded its application for renewable biofuel production. Results In this study, we report the transcriptomic response of a moderately growing subisolate from the culture of Botryococcus sp. CCALA-779 upon nitrogen deprivation (ND). We show that the subisolate has an average growth rate of 0.52 g l−1 day−1 under photoautotrophic growth conditions and lipid content is enhanced to 75 % of CDW upon ND. Both rDNA sequence and hydrocarbon composition analyses indicate that the subisolate belongs to A race B. braunii. Hence, it is designated as B. braunii 779. We show that B. braunii 779 transcriptome shares homology to majo...
An integrated modular continuous multi-purpose pilot scale process plant has been built in the In... more An integrated modular continuous multi-purpose pilot scale process plant has been built in the Institute of Chemical and Engineering Sciences, Singapore to research and develop advanced continuous pharmaceutical production techniques with improved efficiency and quality assurance to support the needs of both local and MNC manufacturers in primary pharmaceutical (active pharmaceutical ingredient) and fine chemicals. With a multi-disciplinary team under one roof, which specialises in process chemistry development, design, analytics, chemometrics, control and modelling, we focus on integrated solutions to processing problems which is distinct from other researches where individual technology fragments prevails. The multipurpose continuous plant has been designed to carry out a range of pharmaceutical complex and multiphase synthetic reactions. Sitting along side with our existing kilo scale batch plant, in-situ comparisons can be done between batch and continuous implementations of the...
Anal. Methods, 2010, 2, 1412-1438 DOI:10.1039/C0AY00257G (Critical Review). Trends in process ana... more Anal. Methods, 2010, 2, 1412-1438 DOI:10.1039/C0AY00257G (Critical Review). Trends in process analytical technology. Wee Chew* and Paul Sharratt. Institute of Chemical and Engineering Sciences (ICES), Agency for Science ...
Although infrared spectroscopy is a very common analytical tool in the chemical sciences, quantit... more Although infrared spectroscopy is a very common analytical tool in the chemical sciences, quantitative infrared spectroscopic studies of multi-component solutions (particularly on-line or in-line studies) have been hampered by the lack of a concise and robust numerical approach. Using an inert chemical species as internal standard, the usual absorbance ratio analysis is generalized into a mathematical form that converts typical absorbance measurement A into its renormalized absorbance Arenorm, with the latter directly relating to the absolute moles rather than the concentration of the constituents. The renormalized absorbance has a number of very important properties, including (1) insensitivity to path length changes due to variations in temperature or pressure of the Fourier transform infrared (FT-IR) cell and (2) insensitivity to solution volume changes arising from reaction, chemical transport, or thermodynamic conditions. The methodology is first applied to a simple model test ...
The band-target entropy minimization method (BTEM) and its variant methods excel at reconstructin... more The band-target entropy minimization method (BTEM) and its variant methods excel at reconstructing known/unknown pure spectra from mixtures without prior information. These mixtures may represent either non-reactive or even reactive systems. In this work, an unsupervised form of the entropy minimization curve resolution, namely, the multi-reconstruction entropy minimization method (MREM), is presented. MREM differs from BTEM by removing the need for band-targets and by introducing a multiple search routine to find multiple local entropy minima. This multiple search routine, which provides a rapid survey of spectral estimates, utilizes a localized form of Corona's simulated annealing method in the optimization. The objective functions and penalty functions of the BTEM type methods are essentially retained. Compared to BTEM type methods, MREM (1) searches for multiple local minima instead of a single global minimum and hence reconstructs many pure component spectra at once instead...
Background The colonial microalga Botryococcus braunii has been brought to people's attention... more Background The colonial microalga Botryococcus braunii has been brought to people's attention for its conspicuous ability to accumulate a variety of lipids including hydrocarbons. B. braunii strains are classified into 3 races based on the types of hydrocarbons. A and B races are known to accumulate high level of lipids. However, their extreme slow growth rate has impeded its application for renewable biofuel production. Results In this study, we report the transcriptomic response of a moderately growing subisolate from the culture of Botryococcus sp. CCALA-779 upon nitrogen deprivation (ND). We show that the subisolate has an average growth rate of 0.52 g l−1 day−1 under photoautotrophic growth conditions and lipid content is enhanced to 75 % of CDW upon ND. Both rDNA sequence and hydrocarbon composition analyses indicate that the subisolate belongs to A race B. braunii. Hence, it is designated as B. braunii 779. We show that B. braunii 779 transcriptome shares homology to majo...
An integrated modular continuous multi-purpose pilot scale process plant has been built in the In... more An integrated modular continuous multi-purpose pilot scale process plant has been built in the Institute of Chemical and Engineering Sciences, Singapore to research and develop advanced continuous pharmaceutical production techniques with improved efficiency and quality assurance to support the needs of both local and MNC manufacturers in primary pharmaceutical (active pharmaceutical ingredient) and fine chemicals. With a multi-disciplinary team under one roof, which specialises in process chemistry development, design, analytics, chemometrics, control and modelling, we focus on integrated solutions to processing problems which is distinct from other researches where individual technology fragments prevails. The multipurpose continuous plant has been designed to carry out a range of pharmaceutical complex and multiphase synthetic reactions. Sitting along side with our existing kilo scale batch plant, in-situ comparisons can be done between batch and continuous implementations of the...
Anal. Methods, 2010, 2, 1412-1438 DOI:10.1039/C0AY00257G (Critical Review). Trends in process ana... more Anal. Methods, 2010, 2, 1412-1438 DOI:10.1039/C0AY00257G (Critical Review). Trends in process analytical technology. Wee Chew* and Paul Sharratt. Institute of Chemical and Engineering Sciences (ICES), Agency for Science ...
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