title: Designing, measuring and modelling a small-scale coil and stimulation circuit for Transcranial Magnetic Stimulation (TMS)

authors: Khokhar, Farah Adeebah

abstract: In TMS rapid electromagnetic fields (EM) are applied to the brain. The fundamental effects of TMS are poorly understood so we need smaller coils to perform invasive measurements on mice. Based on established physics principles we designed and built cylindrical TMS coils consisting of 25 and 50 turns of 0.2 mm diameter copper wire around 5 mm diameter powdered iron cores and discharged a capacitor through these coils. We measured the magnetic flux densities (B-field) of 25 and 50 turn TMS coils with a Hall probe as 907 mT, 750 mT and the induced electric fields (E-field) with a wire loop as 10 – 27 V/m, 10 – 22 V/m at 50 V respectively. We have also modelled the coils with COMSOL Multiphysics which gave similar B-fields for 25 and 50 turn of around 900 mT, 700 mT and E- fields as 20 – 25 V/m, 15 – 20 V/m respectively. The temperature for 25 and 50 turn TMS coils increase by 52 °C and 71 °C respectively after 1200 pulses at 5 Hz. We tried to modulate the activity of a mouse brain slice by stimulating with the 50 turn TMS coil 3 mm above the mouse brain slice with 50 V using a B-field of 500 mT, 600 pulses at 5 Hz. There was no hint that the TMS has changed the activity. Although these coils perform better than previously constructed mouse coils, the EM fields are still considerably lower than human TMS coils of 2 T and 250 V/m.

text: Designing, measuring and modelling a small-scale coil and stimulation circuit for Transcranial Magnetic Stimulation (TMS) In TMS rapid electromagnetic fields (EM) are applied to the brain. The fundamental effects of TMS are poorly understood so we need smaller coils to perform invasive measurements on mice. Based on established physics principles we designed and built cylindrical TMS coils consisting of 25 and 50 turns of 0.2 mm diameter copper wire around 5 mm diameter powdered iron cores and discharged a capacitor through these coils. We measured the magnetic flux densities (B-field) of 25 and 50 turn TMS coils with a Hall probe as 907 mT, 750 mT and the induced electric fields (E-field) with a wire loop as 10 – 27 V/m, 10 – 22 V/m at 50 V respectively. We have also modelled the coils with COMSOL Multiphysics which gave similar B-fields for 25 and 50 turn of around 900 mT, 700 mT and E- fields as 20 – 25 V/m, 15 – 20 V/m respectively. The temperature for 25 and 50 turn TMS coils increase by 52 °C and 71 °C respectively after 1200 pulses at 5 Hz. We tried to modulate the activity of a mouse brain slice by stimulating with the 50 turn TMS coil 3 mm above the mouse brain slice with 50 V using a B-field of 500 mT, 600 pulses at 5 Hz. There was no hint that the TMS has changed the activity. Although these coils perform better than previously constructed mouse coils, the EM fields are still considerably lower than human TMS coils of 2 T and 250 V/m.

year: 2019

title: Academic publishing: A Faustian Bargain?

authors: Samkin, Grant

subjects: author

abstract: This paper documents and shares our experience of navigating the journal-review process. By providing a personal account we aim to provide a piece that will resonate with those who have had similar experiences. We adopted a case-study approach using the reviews of the manuscript by two anonymous reviewers and the authors' responses. The paper confirms the emotive nature of the manuscript-review process and details some of the vagaries associated with the review process, highlighting our frustrations with it. An extensive literature critiquing the manuscript peer-review process exists. This is understandable given the requirement for academics to publish their research findings in peer-reviewed journals. In view of this extensive literature, what is surprising is the dearth of studies detailing how authors have managed to navigate their way through the process.

text: Academic publishing: A Faustian Bargain? This paper documents and shares our experience of navigating the journal-review process. By providing a personal account we aim to provide a piece that will resonate with those who have had similar experiences. We adopted a case-study approach using the reviews of the manuscript by two anonymous reviewers and the authors' responses. The paper confirms the emotive nature of the manuscript-review process and details some of the vagaries associated with the review process, highlighting our frustrations with it. An extensive literature critiquing the manuscript peer-review process exists. This is understandable given the requirement for academics to publish their research findings in peer-reviewed journals. In view of this extensive literature, what is surprising is the dearth of studies detailing how authors have managed to navigate their way through the process.

year: 2011

title: Māori men and the indirect procurement and sharing of prescription medications

authors: Hodgetts, Darrin

subjects: Māori men

abstract: Māori men have higher rates of many diseases and lower life expectancy than other population groups in New Zealand. The general consensus is that these health inequalities are due to the inequitable distribution of the social determinants of health; for example, education, employment, income and housing, and were largely driven by colonization and the social and economic marginalization of Māori. Health care factors, including reluctance to consult doctors or late presentation, are part of this equation, but do not fully explain the disparities in health between Māori men and other population groups. As part of our ongoing work in this area, we draw on a focus group discussion with seven Māori community health workers to provide a preliminary analysis of how some Māori people access and use medications. Particular attention is given to the emergent practice of Māori women presenting to general practitioners (GPs) with proxy symptoms to obtain medications for their male partners. This practice exemplifies a range of strategies that some whānau (family) have developed to navigate the health system and overcome the reluctance of some men to engage with the medical profession. The practice raises issues relating to the nature of “primary” and “whānau” care, accessibility of medical services and medications, adherence to medication regimes and the dynamics of doctor–patient relations.

text: Māori men and the indirect procurement and sharing of prescription medications Māori men have higher rates of many diseases and lower life expectancy than other population groups in New Zealand. The general consensus is that these health inequalities are due to the inequitable distribution of the social determinants of health; for example, education, employment, income and housing, and were largely driven by colonization and the social and economic marginalization of Māori. Health care factors, including reluctance to consult doctors or late presentation, are part of this equation, but do not fully explain the disparities in health between Māori men and other population groups. As part of our ongoing work in this area, we draw on a focus group discussion with seven Māori community health workers to provide a preliminary analysis of how some Māori people access and use medications. Particular attention is given to the emergent practice of Māori women presenting to general practitioners (GPs) with proxy symptoms to obtain medications for their male partners. This practice exemplifies a range of strategies that some whānau (family) have developed to navigate the health system and overcome the reluctance of some men to engage with the medical profession. The practice raises issues relating to the nature of “primary” and “whānau” care, accessibility of medical services and medications, adherence to medication regimes and the dynamics of doctor–patient relations.

year: 2011