title: Dinuclear platinum complexes with designer thiolate ligands from the monoalkylation of [Pt₂(μ-S)₂(PPh₃)₄]

authors: Ujam, Oguejiofo Theophilus

subjects: platinum complexes

abstract: Alkylation reactions of the nucleophilic platinum(II) sulfide complex [Pt₂(μ-S)₂(PPh₃)₄]with functionalised alkylating agents have been investigated as a versatile synthetic route to dinuclear, cationic sulfide-thiolate complexes of the type [Pt₂(μ-S)(μ-SR)(PPh₃)₄]+, extending the range of thiolate complexes that can be prepared using this methodology. A wide range of functional groups can be incorporated, using appropriate alkylating agents, and include ketone, ester, amide, hydrazone, semicarbazone, thiosemicarbazone, oxime, guanidine, urea and thiourea groups.

text: Dinuclear platinum complexes with designer thiolate ligands from the monoalkylation of [Pt₂(μ-S)₂(PPh₃)₄] Alkylation reactions of the nucleophilic platinum(II) sulfide complex [Pt₂(μ-S)₂(PPh₃)₄]with functionalised alkylating agents have been investigated as a versatile synthetic route to dinuclear, cationic sulfide-thiolate complexes of the type [Pt₂(μ-S)(μ-SR)(PPh₃)₄]+, extending the range of thiolate complexes that can be prepared using this methodology. A wide range of functional groups can be incorporated, using appropriate alkylating agents, and include ketone, ester, amide, hydrazone, semicarbazone, thiosemicarbazone, oxime, guanidine, urea and thiourea groups.

year: 2010

title: New insights into the role of pH and aeration in the bacterial production of calcium carbonate (CaCO₃)

authors: Seifan, Mostafa

subjects: Science & Technology

abstract: Over recent years, the implementation of microbially produced calcium carbonate (CaCO₃) in different industrial and environmental applications has become an alternative for conventional approaches to induce CaCO₃ precipitation. However, there are many factors affecting the biomineralization of CaCO₃, which may restrict its application. In this study, we investigated the effects of pH and aeration as the main two influential parameters on bacterial precipitation of CaCO₃. The results showed that the aeration had a significant effect on bacterial growth and its rise from 0.5 to 4.5 SLPM could produce 4.2 times higher CaCO₃ precipitation. The increase of pH to 12 resulted in 6.3-fold increase in CaCO₃ precipitation as compared to uncontrolled-pH fermentation. Morphological characterization showed that the pH is an effective parameter on CaCO₃ morphology. Calcite was found to be the predominant precipitate during aeration-controlled fermentations, while vaterite was mainly produced at lower pH (up to 10) over controlled-pH fermentations. Further increase in pH resulted in a morphological transition, and vaterite transformed to calcite at the pH ranges between 10 and 12.

text: New insights into the role of pH and aeration in the bacterial production of calcium carbonate (CaCO₃) Over recent years, the implementation of microbially produced calcium carbonate (CaCO₃) in different industrial and environmental applications has become an alternative for conventional approaches to induce CaCO₃ precipitation. However, there are many factors affecting the biomineralization of CaCO₃, which may restrict its application. In this study, we investigated the effects of pH and aeration as the main two influential parameters on bacterial precipitation of CaCO₃. The results showed that the aeration had a significant effect on bacterial growth and its rise from 0.5 to 4.5 SLPM could produce 4.2 times higher CaCO₃ precipitation. The increase of pH to 12 resulted in 6.3-fold increase in CaCO₃ precipitation as compared to uncontrolled-pH fermentation. Morphological characterization showed that the pH is an effective parameter on CaCO₃ morphology. Calcite was found to be the predominant precipitate during aeration-controlled fermentations, while vaterite was mainly produced at lower pH (up to 10) over controlled-pH fermentations. Further increase in pH resulted in a morphological transition, and vaterite transformed to calcite at the pH ranges between 10 and 12.

year: 2017

title: Maori perspectives of the environment: A review of policy submissions made by iwi to Environment Waikato.

authors: Whangapirita, Laura

subjects: Maori

abstract: As part of our broader brief to gather, summarise, analyse and distribute information held by Environment Waikato on Maori and the environment, we evaluated and summarised those iwi policy submissions made toward the Proposed Waikato Regional Plan (1998). This report refers to values and beliefs sourced from iwi submissions held by Environment Waikato and are presented within a Maori values framework to highlight environmental perspectives of tangata whenua in the Waikato region.

text: Maori perspectives of the environment: A review of policy submissions made by iwi to Environment Waikato. As part of our broader brief to gather, summarise, analyse and distribute information held by Environment Waikato on Maori and the environment, we evaluated and summarised those iwi policy submissions made toward the Proposed Waikato Regional Plan (1998). This report refers to values and beliefs sourced from iwi submissions held by Environment Waikato and are presented within a Maori values framework to highlight environmental perspectives of tangata whenua in the Waikato region.

year: 2003-10