title: Component-by-component construction of good intermediate-rank lattice rules

authors: Kuo, Frances Y.

subjects: mathematics

abstract: It is known that the generating vector of a rank-1 lattice rule can be constructed component-by-component to achieve strong tractability error bounds in both weighted Korobov spaces and weighted Sobolev spaces. Since the weights for these spaces are nonincreasing, the first few variables are in a sense more important than the rest. We thus propose to copy the points of a rank-1 lattice rule a number of times in the first few dimensions to yield an intermediate-rank lattice rule. We show that the generating vector (and in weighted Sobolev spaces, the shift also) of an intermediate-rank lattice rule can also be constructed component-by-component to achieve strong tractability error bounds. In certain circumstances, these bounds are better than the corresponding bounds for rank-1 lattice rules.

text: Component-by-component construction of good intermediate-rank lattice rules It is known that the generating vector of a rank-1 lattice rule can be constructed component-by-component to achieve strong tractability error bounds in both weighted Korobov spaces and weighted Sobolev spaces. Since the weights for these spaces are nonincreasing, the first few variables are in a sense more important than the rest. We thus propose to copy the points of a rank-1 lattice rule a number of times in the first few dimensions to yield an intermediate-rank lattice rule. We show that the generating vector (and in weighted Sobolev spaces, the shift also) of an intermediate-rank lattice rule can also be constructed component-by-component to achieve strong tractability error bounds. In certain circumstances, these bounds are better than the corresponding bounds for rank-1 lattice rules.

year: 2003

title: Cationic liposome-mediated transfection of mammary epithelial cells with AAV-based plasmid DNA

authors: Whyte, Brett

abstract: Cationic liposome-mediated delivery of adeno-associated virus (AAV) based plasmid DNA has potential for efficient and safe delivery of DNA into a number of different cell types. The objective of this thesis was to develop techniques for transfecting adult somatic mammary epithelial cells with the aim of producing non-germline transgenic animals. Initially, chemical-mediated techniques were used to deliver plasmid DNA to mammary epithelial cells in vitro: this work was subsequently extended to in vivo studies. The research then focussed on cationic liposome-mediated delivery of AAV-based plasmid DNA to enhance transfection efficiency, and the molecular characteristics of AAV-based plasmid DNA as a vector for transfection and integration of DNA into the genome. 

Chemical-mediated procedures were used to deliver plasmid DNA to the mouse mammary epithelial cell line, HC11, and to primary bovine mammary cells in vitro. Four delivery vehicles were used; calcium phosphate co-precipitation, DOTAP, DMRIE-C and LipofectAMINE. The highest transfection efficiency resulted from using LipofectAMINE, although this efficiency was relatively low, with only 2.1% of cells found to express β-galactosidase. 

To establish the efficacy of chemical-mediated delivery of plasmid DNA in vivo and to investigate an intramammary route of delivery, lactating rats were transfected in vivo with plasmid DNA complexed with LipofectAMINE. These complexes were delivered by infusion through the mammary teat canal or by direct injection into the gland. The ensuing level of transfection was extremely low, with only a very small number of rat mammary epithelial cells found to express β-galactosidase. These results indicated that alternative transfection procedures were required. 

Inverted terminal repeats (ITRs) of AAV have previously been shown to enhance transfection efficiency, and these were included in a plasmid construct flanking a β-galactosidase reporter gene. LipofectAMINE was used to deliver this DNA to HC11 cells, however, the efficiency of transient transfection was only increased by a modest 1.4-fold. 

To evaluate the effect of AAV ITRs on plasmid DNA integration, a DNA construct containing a neomycin resistance gene flanked by ITRs was transfected into HC11 cells. Additionally, this construct was co-transfected with an AAV Rep protein expression construct, which is required for site-specific integration in human cells. Neither the inclusion of ITRs, or expression of the rep gene affected the frequency of integration of the neomycin gene. 

In humans a specific advantage of using AAV is site-specific integration of the virus into a locus on human chromosome 19, known as AAVS1. Southern blot analyses were used to ascertain whether a similar site is present in mouse and other species. No clear cut evidence was found for such a site. 

Further Southern blot analysis of clonal lines derived from mouse HC11 cells that were co-transfected with a neomycin resistance gene, and an AAV rep gene construct, suggested that the site of integration was random. A novel PCR technique was utilised to amplify the site of integration. This enabled sequence data to be obtained for two HC11 clones. The site of integration for one of the clones was identified within exon 16 of Mus musculus DNA coding for the DNA dependent protein kinase catalytic subunit. The site of integration for the second clone was an unknown region of the mouse genome. An interesting characteristic of both clones was the presence of mouse B1 repeat sequences in close proximity to the sites of integration. 

These studies demonstrate that AAV-based plasmid DNA can enhance the transfection efficiency in mouse mammary epithelial cells, and they contribute toward the overall knowledge of AAV-based plasmid DNA integration into the mouse genome.

text: Cationic liposome-mediated transfection of mammary epithelial cells with AAV-based plasmid DNA Cationic liposome-mediated delivery of adeno-associated virus (AAV) based plasmid DNA has potential for efficient and safe delivery of DNA into a number of different cell types. The objective of this thesis was to develop techniques for transfecting adult somatic mammary epithelial cells with the aim of producing non-germline transgenic animals. Initially, chemical-mediated techniques were used to deliver plasmid DNA to mammary epithelial cells in vitro: this work was subsequently extended to in vivo studies. The research then focussed on cationic liposome-mediated delivery of AAV-based plasmid DNA to enhance transfection efficiency, and the molecular characteristics of AAV-based plasmid DNA as a vector for transfection and integration of DNA into the genome. 

Chemical-mediated procedures were used to deliver plasmid DNA to the mouse mammary epithelial cell line, HC11, and to primary bovine mammary cells in vitro. Four delivery vehicles were used; calcium phosphate co-precipitation, DOTAP, DMRIE-C and LipofectAMINE. The highest transfection efficiency resulted from using LipofectAMINE, although this efficiency was relatively low, with only 2.1% of cells found to express β-galactosidase. 

To establish the efficacy of chemical-mediated delivery of plasmid DNA in vivo and to investigate an intramammary route of delivery, lactating rats were transfected in vivo with plasmid DNA complexed with LipofectAMINE. These complexes were delivered by infusion through the mammary teat canal or by direct injection into the gland. The ensuing level of transfection was extremely low, with only a very small number of rat mammary epithelial cells found to express β-galactosidase. These results indicated that alternative transfection procedures were required. 

Inverted terminal repeats (ITRs) of AAV have previously been shown to enhance transfection efficiency, and these were included in a plasmid construct flanking a β-galactosidase reporter gene. LipofectAMINE was used to deliver this DNA to HC11 cells, however, the efficiency of transient transfection was only increased by a modest 1.4-fold. 

To evaluate the effect of AAV ITRs on plasmid DNA integration, a DNA construct containing a neomycin resistance gene flanked by ITRs was transfected into HC11 cells. Additionally, this construct was co-transfected with an AAV Rep protein expression construct, which is required for site-specific integration in human cells. Neither the inclusion of ITRs, or expression of the rep gene affected the frequency of integration of the neomycin gene. 

In humans a specific advantage of using AAV is site-specific integration of the virus into a locus on human chromosome 19, known as AAVS1. Southern blot analyses were used to ascertain whether a similar site is present in mouse and other species. No clear cut evidence was found for such a site. 

Further Southern blot analysis of clonal lines derived from mouse HC11 cells that were co-transfected with a neomycin resistance gene, and an AAV rep gene construct, suggested that the site of integration was random. A novel PCR technique was utilised to amplify the site of integration. This enabled sequence data to be obtained for two HC11 clones. The site of integration for one of the clones was identified within exon 16 of Mus musculus DNA coding for the DNA dependent protein kinase catalytic subunit. The site of integration for the second clone was an unknown region of the mouse genome. An interesting characteristic of both clones was the presence of mouse B1 repeat sequences in close proximity to the sites of integration. 

These studies demonstrate that AAV-based plasmid DNA can enhance the transfection efficiency in mouse mammary epithelial cells, and they contribute toward the overall knowledge of AAV-based plasmid DNA integration into the mouse genome.

year: 2001

title: Countering gentrification in Tāmaki Makarau: Towards a framework for urban environmental justice

authors: Terruhn, Jessica

abstract: This policy brief argues for urban policies that actively aim to end gentrification.

Gentrification is intimately tied to state-led processes of urban renewal. Though historically understood as the displacement of low-income households as an unfortunate byproduct of socioeconomic and demographic neighbourhood change, contemporary gentrification is constituted by profit-driven investment decisions that erase undervalued neighbourhoods and their communities in the name of urban renewal (variously referred to as redevelopment, regeneration, renaissance, or revitalisation).

These processes of gentrification fundamentally contribute to environmental injustice. At the same time as creating ‘zones of abundance’, neighbourhood regeneration projects simultaneously (re-)create ‘zones of neglect and sacrifice’, which are burdened with environmental risks. As low-income and ethnic minority households are more likely to either reside in or to be displaced into these neighbourhoods, they are disproportionately exposed to environmental risk factors.

Moreover, gentrification enables and legitimises the exclusion of marginalised communities in multiple ways: 1) it devalues existing places and their residents in favour of regeneration, 2) it displaces longtime residents from regenerated neighbourhoods because of increasing property values, and/or 3) it alienates longtime residents as neighbourhood aesthetics, amenities and services change and become unaffordable and/or irrelevant.

As gentrification contributes to low-income households’ experiences of precarity and severs community ties and place attachments, it generates significant costs to personal and community health and wellbeing as well as social cohesion. The recommendations articulated in this brief emphasise the importance of transformative policy solutions that actively counter gentrification.
These include:
• Equitable investment in urban infrastructure
• Prioritising affordable housing
• Ensuring accessible transportation
• Empowering local communities
• Implementing a Te Tiriti o Waitangi approach to policy development

text: Countering gentrification in Tāmaki Makarau: Towards a framework for urban environmental justice This policy brief argues for urban policies that actively aim to end gentrification.

Gentrification is intimately tied to state-led processes of urban renewal. Though historically understood as the displacement of low-income households as an unfortunate byproduct of socioeconomic and demographic neighbourhood change, contemporary gentrification is constituted by profit-driven investment decisions that erase undervalued neighbourhoods and their communities in the name of urban renewal (variously referred to as redevelopment, regeneration, renaissance, or revitalisation).

These processes of gentrification fundamentally contribute to environmental injustice. At the same time as creating ‘zones of abundance’, neighbourhood regeneration projects simultaneously (re-)create ‘zones of neglect and sacrifice’, which are burdened with environmental risks. As low-income and ethnic minority households are more likely to either reside in or to be displaced into these neighbourhoods, they are disproportionately exposed to environmental risk factors.

Moreover, gentrification enables and legitimises the exclusion of marginalised communities in multiple ways: 1) it devalues existing places and their residents in favour of regeneration, 2) it displaces longtime residents from regenerated neighbourhoods because of increasing property values, and/or 3) it alienates longtime residents as neighbourhood aesthetics, amenities and services change and become unaffordable and/or irrelevant.

As gentrification contributes to low-income households’ experiences of precarity and severs community ties and place attachments, it generates significant costs to personal and community health and wellbeing as well as social cohesion. The recommendations articulated in this brief emphasise the importance of transformative policy solutions that actively counter gentrification.
These include:
• Equitable investment in urban infrastructure
• Prioritising affordable housing
• Ensuring accessible transportation
• Empowering local communities
• Implementing a Te Tiriti o Waitangi approach to policy development

year: 2025