title: The kinetics of the dissociation of dihydroxyacetone dimer in aprotic media

authors: Owens, Adrian

subjects: Dihydroxyacetone

abstract: The dissociation of the dihydroxyacetone (DHA) dimer in mānuka honey has previously been proposed to be the rate determining step in the overall conversion of DHA to methylglyoxal, the agent reported to be responsible for the non-peroxide anti-bacterial activity displayed by mānuka honey.

The ¹H and ¹³C NMR spectra for the DHA dimer and the DHA monomer in DMSO-d6 were assigned using 1D and 2D NMR spectroscopy.

¹H and ¹³C NMR spectroscopy were utilised to investigate the kinetics of the dissociation of the DHA dimer in DMSO-d6, an anhydrous solvent chosen to mimic the dehydrating conditions present in the honey matrix.

Four series of kinetic experiments were conducted, one without catalysis, one with D₂O catalysis, one with CD₃COOD catalysis and one with CD₃COOD/CD₃COOD catalysis. Each of these experiments obtained the equilibrium constant, K and the rate constants k, k₁ and k₋₁ for the dissociation of the DHA dimer under different conditions that may be present in the honey matrix, with the exclusion of the CD₃COOD/CD₃COOD catalysed experiments which were conducted as part of the investigation to determine a proposed reaction mechanism.

Two reaction intermediates were observed in the CD₃COOD catalysed experiments, they were characterised and provided supporting evidence for a proposed acid-catalysed reaction mechanism for the DHA dimer dissociation. The absence of reaction intermediates in the D₂O catalysed experiments provided supporting evidence for a proposed base-catalysed reaction mechanism for the DHA dimer dissociation.

Reaction mechanisms for the DHA dimer dissociation in DMSO-d6 and mānuka honey were proposed based on the findings of previous studies and the findings associated with the kinetic experiments conducted in this study.

text: The kinetics of the dissociation of dihydroxyacetone dimer in aprotic media The dissociation of the dihydroxyacetone (DHA) dimer in mānuka honey has previously been proposed to be the rate determining step in the overall conversion of DHA to methylglyoxal, the agent reported to be responsible for the non-peroxide anti-bacterial activity displayed by mānuka honey.

The ¹H and ¹³C NMR spectra for the DHA dimer and the DHA monomer in DMSO-d6 were assigned using 1D and 2D NMR spectroscopy.

¹H and ¹³C NMR spectroscopy were utilised to investigate the kinetics of the dissociation of the DHA dimer in DMSO-d6, an anhydrous solvent chosen to mimic the dehydrating conditions present in the honey matrix.

Four series of kinetic experiments were conducted, one without catalysis, one with D₂O catalysis, one with CD₃COOD catalysis and one with CD₃COOD/CD₃COOD catalysis. Each of these experiments obtained the equilibrium constant, K and the rate constants k, k₁ and k₋₁ for the dissociation of the DHA dimer under different conditions that may be present in the honey matrix, with the exclusion of the CD₃COOD/CD₃COOD catalysed experiments which were conducted as part of the investigation to determine a proposed reaction mechanism.

Two reaction intermediates were observed in the CD₃COOD catalysed experiments, they were characterised and provided supporting evidence for a proposed acid-catalysed reaction mechanism for the DHA dimer dissociation. The absence of reaction intermediates in the D₂O catalysed experiments provided supporting evidence for a proposed base-catalysed reaction mechanism for the DHA dimer dissociation.

Reaction mechanisms for the DHA dimer dissociation in DMSO-d6 and mānuka honey were proposed based on the findings of previous studies and the findings associated with the kinetic experiments conducted in this study.

year: 2016

title: Keeping pace with technology: drones, disturbance and policy deficiency

authors: Wallace, Philippa Jane

subjects: UAV

abstract: This paper analyses regulatory responses to rapid intensiﬁcation of the use of drones/remotely piloted aircraft (RPA) in the context of wildlife protection. Beneﬁts and disadvantages of the technology to wildlife are examined, before three key limitations in policy and law are identiﬁed: failure to address wildlife disturbance in RPA regulation; reliance upon insufﬁciently comprehensive existing wildlife protection legislation to manage disturbance effects; and limited species-speciﬁc research on disturbance. A New Zealand case study further reveals an inconsistent regulatory approach struggling to keep pace with innovation, inadequate regulatory capture of environmental effects due to exemption as “aircraft”, and no recognition that speciﬁc geographical locations, such as coastal areas, distinguished by recreational pressures and high numbers of threatened species require special consideration. Recommendations include acknowledging the impact on wildlife in policy, gap analysis of legal arrangements for protection from disturbance (including airspace), and adoption of minimum approach distances to threatened species.

text: Keeping pace with technology: drones, disturbance and policy deficiency This paper analyses regulatory responses to rapid intensiﬁcation of the use of drones/remotely piloted aircraft (RPA) in the context of wildlife protection. Beneﬁts and disadvantages of the technology to wildlife are examined, before three key limitations in policy and law are identiﬁed: failure to address wildlife disturbance in RPA regulation; reliance upon insufﬁciently comprehensive existing wildlife protection legislation to manage disturbance effects; and limited species-speciﬁc research on disturbance. A New Zealand case study further reveals an inconsistent regulatory approach struggling to keep pace with innovation, inadequate regulatory capture of environmental effects due to exemption as “aircraft”, and no recognition that speciﬁc geographical locations, such as coastal areas, distinguished by recreational pressures and high numbers of threatened species require special consideration. Recommendations include acknowledging the impact on wildlife in policy, gap analysis of legal arrangements for protection from disturbance (including airspace), and adoption of minimum approach distances to threatened species.

year: 2017

title: Maori women and research: Researching ourselves

authors: Te Awekotuku, Ngahuia

subjects: Maori

abstract: This was the closing keynote address at the Student Symposium organized by the Maori &
Psychology Research Unit at the University of Waikato, Hamilton in August 1999. Most of the
people attending were Maori, and female, and I spoke to, for, and about us. The speech was
transcribed from an oral address with transparencies, and has been revised here for this
publication.

text: Maori women and research: Researching ourselves This was the closing keynote address at the Student Symposium organized by the Maori &
Psychology Research Unit at the University of Waikato, Hamilton in August 1999. Most of the
people attending were Maori, and female, and I spoke to, for, and about us. The speech was
transcribed from an oral address with transparencies, and has been revised here for this
publication.

year: 1999