title: Phosphine functionalized polyaniline nanostructures

authors: Laslau, Cosmin

subjects: polyaniline

abstract: We study the problem of limited functionalization options for polyaniline through the surface attachment of phosphine coupling reagents. These studied linkers are P(CH₂OH)₃ and Ph₂PCH₂OH, and are attached to both conventional and nanostructured polyaniline. Additionally, model compounds are considered, extending the scope of our analysis. The successful attachment results indicate the potential for further functionalization, using the hydroxymethyl terminal groups of the phosphines for primary and secondary amine chemistry. These results should enable the development of sensitive and molecule-specific polyaniline-based devices.

text: Phosphine functionalized polyaniline nanostructures We study the problem of limited functionalization options for polyaniline through the surface attachment of phosphine coupling reagents. These studied linkers are P(CH₂OH)₃ and Ph₂PCH₂OH, and are attached to both conventional and nanostructured polyaniline. Additionally, model compounds are considered, extending the scope of our analysis. The successful attachment results indicate the potential for further functionalization, using the hydroxymethyl terminal groups of the phosphines for primary and secondary amine chemistry. These results should enable the development of sensitive and molecule-specific polyaniline-based devices.

year: 2010

title: Thermophilic methanotrophy in the Taupō volcanic zone

authors: Houghton, Karen M.

subjects: Microbiology

abstract: Methanotrophs are widely distributed in the environment and play an important role in the global methane cycle by oxidising the majority of methane produced each year. Geological sources of methane contribute substantial volumes of this greenhouse gas to the atmosphere, but research on methanotrophs to date has focused on low temperature environments. This study aimed to investigate thermophilic methanotrophy in geothermal environments within the Taupō Volcanic Zone.
A comprehensive survey of methane oxidation in geothermal soils and sediments was carried out, in conjunction with DNA sequencing of 16S rRNA genes from each sample. Methane oxidation is prevalent within the geothermal samples. This is the first survey of methane oxidation of multiple geothermal samples, and emphasises the importance of these ecosystems to the biogeochemical methane cycle. Geothermal samples encompassed highly diverse microbial communities with few ubiquitous genera, and communities were significantly different between methane oxidizing and non-oxidising microcosms. Some methane-oxidising communities did not include 16S rRNA gene sequences from known methanotrophs, suggesting the presence in geothermal ecosystems of taxa currently not recognised as capable of methane oxidation.
Enrichment microcosms were created using the methane-oxidising geothermal samples, and evaluated in terms of methane oxidation and transcriptional activity. Methanotrophy was observed at temperatures between 37 and 75 °C, which complemented the detection of mRNA transcripts for the complete oxidation of methane. Stress response genes were also highly expressed in the microcosms, identifying a variety of mechanisms within the communities to adapt to environmental change. This is the first example of using metatranscriptomics to investigate methanotrophs from geothermal environments and gives insight into the metabolic pathways involved in thermophilic methanotrophy.
Methane-oxidising bacteria were obtained in axenic culture from five enrichment microcosms, confirming the hypothesis that thermophilic methanotrophs could be enriched and isolated from geothermal environments. Many methanotrophs are poorly described in terms of their physiology and ecology, and to address these knowledge gaps, the strains isolated in this study were subjected to thorough phylogenetic and phenotypic characterisation. This research will also facilitate future cultivation, cryostorage and revival of methane oxidisers.
Several described methanotrophs are capable of oxidising hydrogen in addition to methane, but the association between hydrogen oxidation and cell growth is poorly understood. This research aimed to investigate if mixotrophic hydrogen oxidation was used to optimise growth, and if this could be linked to survival at elevated temperatures. [NiFe]- hydrogenases were identified in four of the methanotrophs isolated in this study but hydrogen oxidation was observed in only three of the isolates, which highlights the importance of culture-based investigations to confirm phenotypes predicted by metagenomics. One isolate showed increasing hydrogen oxidation with increasing temperature, but this did not appear to be linked to survival at elevated temperatures.
This study used a combination of culture-independent and cultivation studies to demonstrate that methanotrophs are both abundant and highly active within geothermal environments. Methanotrophs from these ecosystems have also been successfully isolated and characterised, adding to our knowledge both of their physiology and ecological role in methane cycling.

text: Thermophilic methanotrophy in the Taupō volcanic zone Methanotrophs are widely distributed in the environment and play an important role in the global methane cycle by oxidising the majority of methane produced each year. Geological sources of methane contribute substantial volumes of this greenhouse gas to the atmosphere, but research on methanotrophs to date has focused on low temperature environments. This study aimed to investigate thermophilic methanotrophy in geothermal environments within the Taupō Volcanic Zone.
A comprehensive survey of methane oxidation in geothermal soils and sediments was carried out, in conjunction with DNA sequencing of 16S rRNA genes from each sample. Methane oxidation is prevalent within the geothermal samples. This is the first survey of methane oxidation of multiple geothermal samples, and emphasises the importance of these ecosystems to the biogeochemical methane cycle. Geothermal samples encompassed highly diverse microbial communities with few ubiquitous genera, and communities were significantly different between methane oxidizing and non-oxidising microcosms. Some methane-oxidising communities did not include 16S rRNA gene sequences from known methanotrophs, suggesting the presence in geothermal ecosystems of taxa currently not recognised as capable of methane oxidation.
Enrichment microcosms were created using the methane-oxidising geothermal samples, and evaluated in terms of methane oxidation and transcriptional activity. Methanotrophy was observed at temperatures between 37 and 75 °C, which complemented the detection of mRNA transcripts for the complete oxidation of methane. Stress response genes were also highly expressed in the microcosms, identifying a variety of mechanisms within the communities to adapt to environmental change. This is the first example of using metatranscriptomics to investigate methanotrophs from geothermal environments and gives insight into the metabolic pathways involved in thermophilic methanotrophy.
Methane-oxidising bacteria were obtained in axenic culture from five enrichment microcosms, confirming the hypothesis that thermophilic methanotrophs could be enriched and isolated from geothermal environments. Many methanotrophs are poorly described in terms of their physiology and ecology, and to address these knowledge gaps, the strains isolated in this study were subjected to thorough phylogenetic and phenotypic characterisation. This research will also facilitate future cultivation, cryostorage and revival of methane oxidisers.
Several described methanotrophs are capable of oxidising hydrogen in addition to methane, but the association between hydrogen oxidation and cell growth is poorly understood. This research aimed to investigate if mixotrophic hydrogen oxidation was used to optimise growth, and if this could be linked to survival at elevated temperatures. [NiFe]- hydrogenases were identified in four of the methanotrophs isolated in this study but hydrogen oxidation was observed in only three of the isolates, which highlights the importance of culture-based investigations to confirm phenotypes predicted by metagenomics. One isolate showed increasing hydrogen oxidation with increasing temperature, but this did not appear to be linked to survival at elevated temperatures.
This study used a combination of culture-independent and cultivation studies to demonstrate that methanotrophs are both abundant and highly active within geothermal environments. Methanotrophs from these ecosystems have also been successfully isolated and characterised, adding to our knowledge both of their physiology and ecological role in methane cycling.

year: 2018

title: Mahi Toi Skills in Contemporary Education, Training and Maori Development

authors: Joseph, Makarita Ngapine Tangitu

subjects: Kia mau ki nga taonga tuku iho o nga tupuna

abstract: Since the 1980’s, national investment in human capital and skill formation policy in education has been promoted as key to economic success and social inclusion. Social inclusion, however, is often expressed as helping citizens to become employable. Although employability is a key focus of skills formation and education policy, the context of the western ideologies that it derives from and caters to perpetuates the exclusion of mahi toi (arts and crafts) skills in education. Using a kaupapa Māori approach, two key informants who specialise and teach mahi toi skills, either rāranga (weaving) or pounamu (jade/greenstone), were interviewed. The aim was to get a better understanding of how these skills can contribute to personal, professional and Māori development in the 21st century, and to provide information indicating where and how these skills can be learnt, either through private training enterprises (PTE) or public tertiary educational institutions (TEI), thereby highlighting the value of teaching and learning rāranga and pounamu skills. Findings from analysing their pūrākau indicate that learning rāranga or pounamu skills can provide a foundation for believing in your potential, contribute to cultural identity, improve confidence and communication skills, help an individual be bestowed or acquire mana, offer a type of therapy, enhance career progression and professional identity, provide financial rewards and stability, and help with the revitalisation and transfer of cultural knowledge. Ultimately, it is concluded that mahi toi skills such as rāranga and pounamu can contribute to the development of an individual’s personal and professional lives, but also has benefits for the organisation where they become employed as well as extended whānau, hapū and iwi.

text: Mahi Toi Skills in Contemporary Education, Training and Maori Development Since the 1980’s, national investment in human capital and skill formation policy in education has been promoted as key to economic success and social inclusion. Social inclusion, however, is often expressed as helping citizens to become employable. Although employability is a key focus of skills formation and education policy, the context of the western ideologies that it derives from and caters to perpetuates the exclusion of mahi toi (arts and crafts) skills in education. Using a kaupapa Māori approach, two key informants who specialise and teach mahi toi skills, either rāranga (weaving) or pounamu (jade/greenstone), were interviewed. The aim was to get a better understanding of how these skills can contribute to personal, professional and Māori development in the 21st century, and to provide information indicating where and how these skills can be learnt, either through private training enterprises (PTE) or public tertiary educational institutions (TEI), thereby highlighting the value of teaching and learning rāranga and pounamu skills. Findings from analysing their pūrākau indicate that learning rāranga or pounamu skills can provide a foundation for believing in your potential, contribute to cultural identity, improve confidence and communication skills, help an individual be bestowed or acquire mana, offer a type of therapy, enhance career progression and professional identity, provide financial rewards and stability, and help with the revitalisation and transfer of cultural knowledge. Ultimately, it is concluded that mahi toi skills such as rāranga and pounamu can contribute to the development of an individual’s personal and professional lives, but also has benefits for the organisation where they become employed as well as extended whānau, hapū and iwi.

year: 2018