title: Measuring the electrical impedance of mouse brain tissue

authors: Wilson, Marcus T.

abstract: We report on an experimental method to measure conductivity of cortical tissue. We use a pair of 5mm diameter Ag/AgCl electrodes in a Perspex sandwich device that can be brought to a distance of 400 microns apart. The apparatus is brought to uniform temperature before use. Electrical impedance of a sample is measured across the frequency range 20 Hz-2.0 MHz with an Agilent 4980A four-point impedance monitor in a shielded room. The equipment has been used to measure the conductivity of mature mouse brain cortex in vitro. Slices 400 microns in thickness are prepared on a vibratome. Slices are bathed in artificial cerebrospinal fluid (ACSF) to keep them alive. Slices are removed from the ACSF and sections of cortical tissue approximately 2 mm times 2 mm are cut with a razor blade. The sections are photographed through a calibrated microscope to allow identification of their cross-sectional areas. Excess ACSF is removed from the sample and the sections places between the electrodes. The impedance is measured across the frequency range and electrical conductivity calculated. Results show two regions of dispersion. A low frequency region is evident below approximately 10 kHz, and a high frequency dispersion above this. Results at the higher frequencies show a good fit to the Cole-Cole model of impedance of biological tissue; this model consists of resistive and non-linear capacitive elements. Physically, these elements are likely to arise due to membrane polarization and migration of ions both intra- and extra-cellularly.

text: Measuring the electrical impedance of mouse brain tissue We report on an experimental method to measure conductivity of cortical tissue. We use a pair of 5mm diameter Ag/AgCl electrodes in a Perspex sandwich device that can be brought to a distance of 400 microns apart. The apparatus is brought to uniform temperature before use. Electrical impedance of a sample is measured across the frequency range 20 Hz-2.0 MHz with an Agilent 4980A four-point impedance monitor in a shielded room. The equipment has been used to measure the conductivity of mature mouse brain cortex in vitro. Slices 400 microns in thickness are prepared on a vibratome. Slices are bathed in artificial cerebrospinal fluid (ACSF) to keep them alive. Slices are removed from the ACSF and sections of cortical tissue approximately 2 mm times 2 mm are cut with a razor blade. The sections are photographed through a calibrated microscope to allow identification of their cross-sectional areas. Excess ACSF is removed from the sample and the sections places between the electrodes. The impedance is measured across the frequency range and electrical conductivity calculated. Results show two regions of dispersion. A low frequency region is evident below approximately 10 kHz, and a high frequency dispersion above this. Results at the higher frequencies show a good fit to the Cole-Cole model of impedance of biological tissue; this model consists of resistive and non-linear capacitive elements. Physically, these elements are likely to arise due to membrane polarization and migration of ions both intra- and extra-cellularly.

year: 2014

title: There must be a better way - The case against the New Zealand Literacy Strategy and some examples of how we can help students who fall by the wayside

authors: Dymock, Susan

abstract: Literate cultural capital is a phrase used to describe the literacy knowledge and skills children have on school entry (Prochnow, Tunmer & Arrow, 2015; Tunmer & Nicholson, 2011). Literacy knowledge and skills include oral language, vocabulary, an awareness of how books operate, letter name knowledge, letter sound knowledge, phonological awareness, and invented spelling (Prochnow, Tunmer & Arrow, 2015). Children who commence school with a good level of literate cultural capital are advantaged and are more likely to develop age-appropriate reading skills as they progress through school compared to children who commence school with little literate cultural capital.

text: There must be a better way - The case against the New Zealand Literacy Strategy and some examples of how we can help students who fall by the wayside Literate cultural capital is a phrase used to describe the literacy knowledge and skills children have on school entry (Prochnow, Tunmer & Arrow, 2015; Tunmer & Nicholson, 2011). Literacy knowledge and skills include oral language, vocabulary, an awareness of how books operate, letter name knowledge, letter sound knowledge, phonological awareness, and invented spelling (Prochnow, Tunmer & Arrow, 2015). Children who commence school with a good level of literate cultural capital are advantaged and are more likely to develop age-appropriate reading skills as they progress through school compared to children who commence school with little literate cultural capital.

year: 2017

title: Is there a lack of science resources and specialists for kaiako at Kura reo o Waikato?

authors: Hopkins, Aareka

subjects: Kura kaupapa

abstract: The New Zealand debates on culture and science education for Maaori are grounded in the concern for the under-achievement of tauira in science. In 1995, a lack of subject experts, specialists and resources to implement the Ministry of Education’s science curriculum was identified. I investigated the concept of a mobile science laboratory to provide subject experts, specialists and resources to Kura Reo o Tainui as a way of improving and enhancing tauira literacy and engagement in puutaiao. This study used a semi-structured survey to elicit the whakaaro and perceptions of kaiako puutaiao from four Wharekura, three Kura Kaupapa Maaori, and three Rumaki Total Immersion classes in Waikato-Tainui, using registered participants in the inaugural Kura Reo o Tainui Waananga in 2008 to select survey participants.

text: Is there a lack of science resources and specialists for kaiako at Kura reo o Waikato? The New Zealand debates on culture and science education for Maaori are grounded in the concern for the under-achievement of tauira in science. In 1995, a lack of subject experts, specialists and resources to implement the Ministry of Education’s science curriculum was identified. I investigated the concept of a mobile science laboratory to provide subject experts, specialists and resources to Kura Reo o Tainui as a way of improving and enhancing tauira literacy and engagement in puutaiao. This study used a semi-structured survey to elicit the whakaaro and perceptions of kaiako puutaiao from four Wharekura, three Kura Kaupapa Maaori, and three Rumaki Total Immersion classes in Waikato-Tainui, using registered participants in the inaugural Kura Reo o Tainui Waananga in 2008 to select survey participants.

year: 2010-08