title: Development of a novel cyanide-free method for analysis of vitamin B₁₂ in milk-based infant formula

authors: Li, Yanan

abstract: The analysis of vitamin B₁₂ in infant formulas requires the use of cyanide during the sample preparation process to convert the three unstable vitamers (hydroxocobalamin, methylcobalamin and adenosylcobalamin) to cyanocobalamin, the most stable form of vitamin B₁₂. The undesirable handling of cyanide for the analyst in the laboratory and the associated safety risk indicates a clear necessity for development of a cyanide-free method for vitamin B₁₂ analysis without compromising the analytical quality.
This doctoral research demonstrates the possibility of using cobalamin-derived α-ribazole to represent total vitamin B₁₂, since the α-ribazole exists in all vitamin B₁₂ forms removing the necessity for conversion. The absence of a commercial standard of α-ribazole required its in-house isolation from a cyanocobalamin standard. The α-ribazole was released through consecutive acidic hydrolysis and dephosphorylation by alkaline phosphatase. The freed α-ribazole was collected by boronate affinity chromatography and concentrated by lyophilisation. α-Ribazole was identified and characterised by nuclear magnetic resonance spectroscopy and liquid chromatography mass spectrometry to demonstrate its suitability as a standard. This protocol was optimised and adopted in the sample preparation for analysing vitamin B₁₂ in infant formulas. Several extra steps were added to eliminate or limit interferences, including protein denaturation and sugar removal using C₁₈ solid phase extraction. The final analyte was quantified using hydrophilic interaction liquid chromatography with fluorescence detection.
The single laboratory validation experiment showed that this cyanide-free method is fit for purpose. Analysis of various milk-based infant formulas and comparison with current procedure demonstrated no bias for vitamin B₁₂ analysis.

text: Development of a novel cyanide-free method for analysis of vitamin B₁₂ in milk-based infant formula The analysis of vitamin B₁₂ in infant formulas requires the use of cyanide during the sample preparation process to convert the three unstable vitamers (hydroxocobalamin, methylcobalamin and adenosylcobalamin) to cyanocobalamin, the most stable form of vitamin B₁₂. The undesirable handling of cyanide for the analyst in the laboratory and the associated safety risk indicates a clear necessity for development of a cyanide-free method for vitamin B₁₂ analysis without compromising the analytical quality.
This doctoral research demonstrates the possibility of using cobalamin-derived α-ribazole to represent total vitamin B₁₂, since the α-ribazole exists in all vitamin B₁₂ forms removing the necessity for conversion. The absence of a commercial standard of α-ribazole required its in-house isolation from a cyanocobalamin standard. The α-ribazole was released through consecutive acidic hydrolysis and dephosphorylation by alkaline phosphatase. The freed α-ribazole was collected by boronate affinity chromatography and concentrated by lyophilisation. α-Ribazole was identified and characterised by nuclear magnetic resonance spectroscopy and liquid chromatography mass spectrometry to demonstrate its suitability as a standard. This protocol was optimised and adopted in the sample preparation for analysing vitamin B₁₂ in infant formulas. Several extra steps were added to eliminate or limit interferences, including protein denaturation and sugar removal using C₁₈ solid phase extraction. The final analyte was quantified using hydrophilic interaction liquid chromatography with fluorescence detection.
The single laboratory validation experiment showed that this cyanide-free method is fit for purpose. Analysis of various milk-based infant formulas and comparison with current procedure demonstrated no bias for vitamin B₁₂ analysis.

year: 2023

title: On the chromatic index of Latin squares

authors: Cavenagh, Nicholas J.

abstract: A proper coloring of a Latin square of order n is an assignment of colors to its elements triples such that each row, column and symbol is assigned n distinct colors. Equivalently, a proper coloring of a Latin square is a partition into partial transversals. The chromatic index of a Latin square is the least number of colors needed for a proper coloring. We study the chromatic index of the cyclic Latin square which arises from the addition table for the integers modulo n. We obtain the best possible bounds except for the case when n=2 is odd and divisible by 3. We make some conjectures about the chromatic index, suggesting a generalization of Ryser's conjecture (that every Latin square of odd order contains a transversal).

text: On the chromatic index of Latin squares A proper coloring of a Latin square of order n is an assignment of colors to its elements triples such that each row, column and symbol is assigned n distinct colors. Equivalently, a proper coloring of a Latin square is a partition into partial transversals. The chromatic index of a Latin square is the least number of colors needed for a proper coloring. We study the chromatic index of the cyclic Latin square which arises from the addition table for the integers modulo n. We obtain the best possible bounds except for the case when n=2 is odd and divisible by 3. We make some conjectures about the chromatic index, suggesting a generalization of Ryser's conjecture (that every Latin square of odd order contains a transversal).

year: 2015

title: The southern initiative: How indigenous values inspire social innovation and impact

authors: Niu, Xiaoliang

abstract: Indigenous values are increasingly recognised in helping organisations contribute to wellbeing within and beyond the workplace. Adopting the theoretical lens of Māori economies of wellbeing, this case study examines how The Southern Initiative (TSI), a unit within Auckland Council, incorporates Māori values to co-create place-based solutions and foster whānau (family) wellbeing. Through kōrero (conversations) with three people, a wānanga (collaborative discussion) with TSI members, and analysis of organisational literature, we identified how TSI's organising approach synthesises social innovation and bureaucracy. We found that indigeneity-embedded intrapreneurship, distributed leadership, and whānau-centred design support TSI's innovations. Mana (prestige) emerged as a primary organising principle, sustaining TSI's approach to achieving systemic change. By bridging Indigenous paradigms and conventional managerial practice, this case study demonstrates how Māori values can transform public sector management, elevate social justice, and encourage community resilience. These findings highlight culturally grounded frameworks for delivering social impact and shaping equitable outcomes.

text: The southern initiative: How indigenous values inspire social innovation and impact Indigenous values are increasingly recognised in helping organisations contribute to wellbeing within and beyond the workplace. Adopting the theoretical lens of Māori economies of wellbeing, this case study examines how The Southern Initiative (TSI), a unit within Auckland Council, incorporates Māori values to co-create place-based solutions and foster whānau (family) wellbeing. Through kōrero (conversations) with three people, a wānanga (collaborative discussion) with TSI members, and analysis of organisational literature, we identified how TSI's organising approach synthesises social innovation and bureaucracy. We found that indigeneity-embedded intrapreneurship, distributed leadership, and whānau-centred design support TSI's innovations. Mana (prestige) emerged as a primary organising principle, sustaining TSI's approach to achieving systemic change. By bridging Indigenous paradigms and conventional managerial practice, this case study demonstrates how Māori values can transform public sector management, elevate social justice, and encourage community resilience. These findings highlight culturally grounded frameworks for delivering social impact and shaping equitable outcomes.

year: 2025