title: Structural studies of some compounds containing C₂ fragments attached to various metal-ligand end-groups

authors: Bruce, Michael I.

subjects: C₂ ligands

abstract: The preparation, characterisation and single-crystal XRD molecular structure determinations of four complexes containing –CC–MLn end-groups, namely Ru{C≡CFc′(I)}(dppe)Cp (1), the vinylidene [Os(=C=CH₂)(PPh₃)₂Cp]PF₆ (2), trans-Pt(C≡CC₆H₄-4-C≡CPh){C≡CC₆H₄-4-C₂Ph[Co₂(μ-dppm)(CO)₄]}(PPh₃)₂ (3), and C₆H₄{μ₃-C₂[AuRu₃(CO)₉(PPh₃)]}₂-1,4 (4) are reported. In these compounds a range of –CC– environments is found, extending from the σ-bonded alkynyl group in 1 to examples where the C₂ unit interacts with either a proton (in vinylidene 2), by bridging a dicobalt carbonyl moiety (in 3) or the AuRu₃ cluster in 4. Changes in geometry are rationalised by considering the various bonding modes.

text: Structural studies of some compounds containing C₂ fragments attached to various metal-ligand end-groups The preparation, characterisation and single-crystal XRD molecular structure determinations of four complexes containing –CC–MLn end-groups, namely Ru{C≡CFc′(I)}(dppe)Cp (1), the vinylidene [Os(=C=CH₂)(PPh₃)₂Cp]PF₆ (2), trans-Pt(C≡CC₆H₄-4-C≡CPh){C≡CC₆H₄-4-C₂Ph[Co₂(μ-dppm)(CO)₄]}(PPh₃)₂ (3), and C₆H₄{μ₃-C₂[AuRu₃(CO)₉(PPh₃)]}₂-1,4 (4) are reported. In these compounds a range of –CC– environments is found, extending from the σ-bonded alkynyl group in 1 to examples where the C₂ unit interacts with either a proton (in vinylidene 2), by bridging a dicobalt carbonyl moiety (in 3) or the AuRu₃ cluster in 4. Changes in geometry are rationalised by considering the various bonding modes.

year: 2011

title: Passive in-situ estrogenic potency sampling with DGT-YES

authors: Iuele, Helena

abstract: The purpose of this research was to investigate the presence of bisphenolic plastics and synthetic estrogens in municipal water systems, as well as along the Waikato River. The concentration of these compounds was assessed using a novel combination of methods that allowed the actual levels of endocrine disruption to be ascertained. This was based on diffusive gradients in thin films (DGTs) coupled with high-performance liquid chromatography/mass spectrometry analysis (HPLC/MS) and the Yeast Estrogen Screen (YES).
DGT estimated time-integrated concentrations while HPLC/MS ensured a robust, automated and sensitive routine analysis. Most significantly, YES, a biomarker-based assay, was deployed to quantify the total estrogenic potency of the compounds adsorbed to the DGT matrix. The unique dimension of this research was to extend the application of DGTs to estrogen sampling and to combine the DGT and YES technique to provide in situ quantification of the estrogenic potency of water bodies through time.
DGTs were developed specifically for the sampling of BPA, BPAF, E2 and EE2. Several physical-chemical and chemical analyses were conducted to attest the suitability of the agarose (1.5%) and agarose (1.5%) – activated charcoal (1%) chosen respectively as diffusive gel and binding gel. They were found to be suitable for the detection of organic molecules with a bigger steric hindrance and agarose (1.5%) – AC (1%) appeared suitable for long deployments thanks to its high thermal resistance. An HPLC-MS method was optimised to quantify the compounds of interest. A methanol (MeOH, NH4OH 0.06 M)/water (H2O, NH4OH 0.06 M) fast gradient elution program of 15 min was chosen to elute the analytes, MS parameters were optimized for each compound and the negative mode was selected to perform the fragmentation. LODs and LOQs of all targets resulted in the nanomolar range assuming 24 h as deployment time at 25°C with a 0.54 mm thick diffusive gel. The sensitivity of the method was increased in the sub-nanomolar range by adopting long deployment times (18 days) thus enhancing the accumulation of the targets.The YES was successfully developed to quantify the total estrogenic potency of the DGTs eluted. The dose-response calibration curve of E2, employed as a control, demonstrated LOD and experimental EC50 values in the sub-nanomolar range. EE2, BPA and BPAF demonstrated agonistic endocrine activity, in particular EE2 being more potent than E2, while BPAF and BPA were less potent.
The environmental monitoring assessed the efficiency of removal of the selected ECs during the water treatment processes from river-to-tap and effluent-to-treated wastewater in Hamilton as well the water quality from source-to-outfall of the Waikato River. The HPLC-MS and YES results highlighted that primary treatments were not suitable for the removal of bisphenolic plastics and estrogens both at drinkable and wastewater treatment plants in Hamilton where they appear to worsen the water quality making these pollutants more available. At both treatment plants, the concentration and the estrogenic activity of the targets appeared to fluctuate around the same value, pointing out the inefficiency of removal of these compounds with the actual treatments. EE2 contributed the most to the estrogenic activity due to its higher concentration and higher potency at all sites.
The concentration and the estrogenic potency of all targets were found to be higher downstream at all sites monitored along the Waikato River. EE2 was the compound with the highest concentration at all sites. A moderate worsening of water quality was apparent moving from Taupo to Tuakau. The most polluted sites were Hamilton and Huntley after the outlets of wastewater treatment plants that serve the main conurbations in the area. The EDC concentrations recorded in November 2017 and February 2018 during the monitoring of the Waikato River at Hamilton upstream and downstream sites showed a significant dilution due to the weather conditions.
The data from a previous monitoring of the Waikato River adopting an SPE-HRGC/MS method were compared with those of the DGT-HPLC/MS investigation. The water quality appeared slightly worsened at all sites from 2013 to 2018 due to increased concentrations of BPA and EE2. The DGT-HPLC/MS quantification with the YES assay proved that not only active samplings but passive samplings as well can be coupled with a bioassay. This combined approach had the excellent potential to provide a reliable total estrogenic potency evaluation with time integrated concentrations. The use of the assay allowed estimation of the total estrogenic potency of the eluted DGT. The eluate appeared enriched by other compounds with estrogenic activity, suggesting this type of DGT could be suitable for the sampling and accumulation of other analytes that could be further investigated via HPLC/MS analysis. Compared to the traditional active approaches, DGT ensured sampling and concentration in one step, was easy to prepare and to use, required a very simple sample preparation step prior to analysis, and provided sensitivity in the sub-nanomolar range comparable to active sampling analyses. The YES assay was responsive, robust and easy to use compared to other assays that require laborious procedures and longer times for estrogenic potency evaluation and high sensitivity in the sub-nanomolar range comparable to other assays.

text: Passive in-situ estrogenic potency sampling with DGT-YES The purpose of this research was to investigate the presence of bisphenolic plastics and synthetic estrogens in municipal water systems, as well as along the Waikato River. The concentration of these compounds was assessed using a novel combination of methods that allowed the actual levels of endocrine disruption to be ascertained. This was based on diffusive gradients in thin films (DGTs) coupled with high-performance liquid chromatography/mass spectrometry analysis (HPLC/MS) and the Yeast Estrogen Screen (YES).
DGT estimated time-integrated concentrations while HPLC/MS ensured a robust, automated and sensitive routine analysis. Most significantly, YES, a biomarker-based assay, was deployed to quantify the total estrogenic potency of the compounds adsorbed to the DGT matrix. The unique dimension of this research was to extend the application of DGTs to estrogen sampling and to combine the DGT and YES technique to provide in situ quantification of the estrogenic potency of water bodies through time.
DGTs were developed specifically for the sampling of BPA, BPAF, E2 and EE2. Several physical-chemical and chemical analyses were conducted to attest the suitability of the agarose (1.5%) and agarose (1.5%) – activated charcoal (1%) chosen respectively as diffusive gel and binding gel. They were found to be suitable for the detection of organic molecules with a bigger steric hindrance and agarose (1.5%) – AC (1%) appeared suitable for long deployments thanks to its high thermal resistance. An HPLC-MS method was optimised to quantify the compounds of interest. A methanol (MeOH, NH4OH 0.06 M)/water (H2O, NH4OH 0.06 M) fast gradient elution program of 15 min was chosen to elute the analytes, MS parameters were optimized for each compound and the negative mode was selected to perform the fragmentation. LODs and LOQs of all targets resulted in the nanomolar range assuming 24 h as deployment time at 25°C with a 0.54 mm thick diffusive gel. The sensitivity of the method was increased in the sub-nanomolar range by adopting long deployment times (18 days) thus enhancing the accumulation of the targets.The YES was successfully developed to quantify the total estrogenic potency of the DGTs eluted. The dose-response calibration curve of E2, employed as a control, demonstrated LOD and experimental EC50 values in the sub-nanomolar range. EE2, BPA and BPAF demonstrated agonistic endocrine activity, in particular EE2 being more potent than E2, while BPAF and BPA were less potent.
The environmental monitoring assessed the efficiency of removal of the selected ECs during the water treatment processes from river-to-tap and effluent-to-treated wastewater in Hamilton as well the water quality from source-to-outfall of the Waikato River. The HPLC-MS and YES results highlighted that primary treatments were not suitable for the removal of bisphenolic plastics and estrogens both at drinkable and wastewater treatment plants in Hamilton where they appear to worsen the water quality making these pollutants more available. At both treatment plants, the concentration and the estrogenic activity of the targets appeared to fluctuate around the same value, pointing out the inefficiency of removal of these compounds with the actual treatments. EE2 contributed the most to the estrogenic activity due to its higher concentration and higher potency at all sites.
The concentration and the estrogenic potency of all targets were found to be higher downstream at all sites monitored along the Waikato River. EE2 was the compound with the highest concentration at all sites. A moderate worsening of water quality was apparent moving from Taupo to Tuakau. The most polluted sites were Hamilton and Huntley after the outlets of wastewater treatment plants that serve the main conurbations in the area. The EDC concentrations recorded in November 2017 and February 2018 during the monitoring of the Waikato River at Hamilton upstream and downstream sites showed a significant dilution due to the weather conditions.
The data from a previous monitoring of the Waikato River adopting an SPE-HRGC/MS method were compared with those of the DGT-HPLC/MS investigation. The water quality appeared slightly worsened at all sites from 2013 to 2018 due to increased concentrations of BPA and EE2. The DGT-HPLC/MS quantification with the YES assay proved that not only active samplings but passive samplings as well can be coupled with a bioassay. This combined approach had the excellent potential to provide a reliable total estrogenic potency evaluation with time integrated concentrations. The use of the assay allowed estimation of the total estrogenic potency of the eluted DGT. The eluate appeared enriched by other compounds with estrogenic activity, suggesting this type of DGT could be suitable for the sampling and accumulation of other analytes that could be further investigated via HPLC/MS analysis. Compared to the traditional active approaches, DGT ensured sampling and concentration in one step, was easy to prepare and to use, required a very simple sample preparation step prior to analysis, and provided sensitivity in the sub-nanomolar range comparable to active sampling analyses. The YES assay was responsive, robust and easy to use compared to other assays that require laborious procedures and longer times for estrogenic potency evaluation and high sensitivity in the sub-nanomolar range comparable to other assays.

year: 2019

title: Homeless Māori Men: Re-connection, Re-joining, and Re-membering Ways of Being

authors: King, Pita Richard Wiremu

subjects: Māori psychology

abstract: There are a range of interventions and programmes to address the on-going issue of Māori homelessness. This thesis explores a gardening project hosted by a Ngāti Whātua marae (communal complex used for everyday Māori life) in Auckland for homeless Māori men. The garden project facilitates a sense of belonging, dignity, purpose, meaning and connectedness with other Māori people. It provides insights into how culturally-patterned relationships are centrally important to resolving the overrepresentation of indigenous peoples’ in homelessness populations. I employ the use of semi-structured interviews, reflective journaling, and photography as techniques to record and document the daily interactions in the marae gardens. Participants came from three distinct groups, which include: homeless Māori men, the Auckland City Mission, and Ngāti Whātua o Orakei. A total of eight participants were formally interviewed, along with another six who engaged in casual conversations, in this research, with ages ranged from 30 to 70 years of age. Key findings from this research relate to the construction and preservation of Māori identity while in a state of homelessness, the functioning of marae as spaces of care that foster the wellbeing of Māori, and the role of food in the reproduction of Māori cultural values in everyday life. The broader significance of my work is to use indigenous concepts to build an understanding of the activities, needs and relationships of homeless Māori men that they can recognise themselves from.

text: Homeless Māori Men: Re-connection, Re-joining, and Re-membering Ways of Being There are a range of interventions and programmes to address the on-going issue of Māori homelessness. This thesis explores a gardening project hosted by a Ngāti Whātua marae (communal complex used for everyday Māori life) in Auckland for homeless Māori men. The garden project facilitates a sense of belonging, dignity, purpose, meaning and connectedness with other Māori people. It provides insights into how culturally-patterned relationships are centrally important to resolving the overrepresentation of indigenous peoples’ in homelessness populations. I employ the use of semi-structured interviews, reflective journaling, and photography as techniques to record and document the daily interactions in the marae gardens. Participants came from three distinct groups, which include: homeless Māori men, the Auckland City Mission, and Ngāti Whātua o Orakei. A total of eight participants were formally interviewed, along with another six who engaged in casual conversations, in this research, with ages ranged from 30 to 70 years of age. Key findings from this research relate to the construction and preservation of Māori identity while in a state of homelessness, the functioning of marae as spaces of care that foster the wellbeing of Māori, and the role of food in the reproduction of Māori cultural values in everyday life. The broader significance of my work is to use indigenous concepts to build an understanding of the activities, needs and relationships of homeless Māori men that they can recognise themselves from.

year: 2014