title: Design and demonstration in vitro of a mouse-specific Transcranial Magnetic Stimulation coil

authors: Khokhar, Farah Adeebah

abstract: Background. Transcranial Magnetic Stimulation (TMS) is a technique used to treat different neurological disorders non-invasively. A pulsed current to a coil generates a magnetic field (B-field) which induces an electric field (E-field). Underlying biophysical effects of TMS are unclear. Therefore, animal experiments are needed; however, making small TMS coils suitable for mice is difficult and their field strengths are typically much lower than for human sized coils. Objectives/Hypothesis. We aimed to design and demonstrate a mouse-specific coil that can generate high and focused E-field. Methods. We designed a tapered TMS coil of 50 turns of 0.2 mm diameter copper wire around a 5 mm diameter tapered powdered iron core and discharged a 220 μF capacitor at 50 V through it. We measured B-field with a Hall probe and induced E-field with a wire loop. We measured temperature rise with a thermocouple. We applied 1200 pulses of continuous theta burst stimulation (cTBS) and intermittent theta burst stimulation (iTBS) to mouse brain slices and analysed how spontaneous electrical activity changed. Results. The coil gave maximum B-field of 685 mT at the base of the coil and 340 mT at 2 mm below the coil, and maximum E-field 2 mm below the coil of approximately 10 V/m, at 50 V power supply, with a temperature increase of 20 degrees after 1200 pulses of cTBS. We observed no changes in B-field with heating. cTBS reduced frequency of spontaneous population events in mouse brain slices up to 20 minutes after stimulation and iTBS increased frequency up to 20 minutes after stimulation. No frequency changes occurred after 20 minutes. No changes in amplitude of spontaneous events were found. Conclusion. The design generated fields strong enough to modulate brain activity in vitro.

text: Design and demonstration in vitro of a mouse-specific Transcranial Magnetic Stimulation coil Background. Transcranial Magnetic Stimulation (TMS) is a technique used to treat different neurological disorders non-invasively. A pulsed current to a coil generates a magnetic field (B-field) which induces an electric field (E-field). Underlying biophysical effects of TMS are unclear. Therefore, animal experiments are needed; however, making small TMS coils suitable for mice is difficult and their field strengths are typically much lower than for human sized coils. Objectives/Hypothesis. We aimed to design and demonstrate a mouse-specific coil that can generate high and focused E-field. Methods. We designed a tapered TMS coil of 50 turns of 0.2 mm diameter copper wire around a 5 mm diameter tapered powdered iron core and discharged a 220 μF capacitor at 50 V through it. We measured B-field with a Hall probe and induced E-field with a wire loop. We measured temperature rise with a thermocouple. We applied 1200 pulses of continuous theta burst stimulation (cTBS) and intermittent theta burst stimulation (iTBS) to mouse brain slices and analysed how spontaneous electrical activity changed. Results. The coil gave maximum B-field of 685 mT at the base of the coil and 340 mT at 2 mm below the coil, and maximum E-field 2 mm below the coil of approximately 10 V/m, at 50 V power supply, with a temperature increase of 20 degrees after 1200 pulses of cTBS. We observed no changes in B-field with heating. cTBS reduced frequency of spontaneous population events in mouse brain slices up to 20 minutes after stimulation and iTBS increased frequency up to 20 minutes after stimulation. No frequency changes occurred after 20 minutes. No changes in amplitude of spontaneous events were found. Conclusion. The design generated fields strong enough to modulate brain activity in vitro.

year: 2021

title: Two faiths, one banner: when Muslims marched with Christians across Europe’s battlegrounds [Book review]

authors: Pratt, Douglas

subjects: book review

abstract: This article reviews the book “Two faiths, one banner: when Muslims marched with Christians across Europe’s battlegrounds”, by Ian Almond.

text: Two faiths, one banner: when Muslims marched with Christians across Europe’s battlegrounds [Book review] This article reviews the book “Two faiths, one banner: when Muslims marched with Christians across Europe’s battlegrounds”, by Ian Almond.

year: 2010-10

title: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books

authors: Daly, Nicola

subjects: New Zealand

abstract: When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

text: Kūkupa, koro, and kai: The use of Māori vocabulary items in New Zealand English children's picture books When a linguistic form from one language is used in another language, such words are known as borrowings or loan words (Crystal 2003: 56). The English language is renowned for its large capacity for borrowing and it has been suggested that the growth in internationalism in recent times has led to people seeking new words to indicate their local identity (Crystal 1995; Crystal 2003). Certainly this is the case of New Zealand English, the most distinctive aspect of which is borrowings from te reo Maori (Deverson 1991). In 1984 Deverson estimated that most New Zealanders have a passive knowledge of at least 40-50 borrowed Maori loan words (Deverson 1984). This figure has been recently revised by Macalister to 70-80 such words (20,-,63.). A study of the frequency of Maori loan words in New Zealand English in New Zealand School Journals of the 1960s and 1990s showed an incidence of around 6 words per 1,000 (Macalister 1999). Kennedy and Yamazaki (1999) also found borrowed Maori words at a rate of 6 per thousand words. Macalister (2006b) has examined the use of Maori loan words in New Zealand English across a 150 year period from 1850-2000. He examined a corpus of a little under five and a half million words from three sources: Newspapers, parliamentary debates and School Journals. Across the three sources there was an increase from 3.29 words per 1,000 in 1850 to 8.8 per thousand in 2000. Macalister lists the reasons for this change as including urbanisation of the Maori population between 1945 and 1975, which created more contact; the changing status of the Maori language with the kOhanga reo movement; the establishment of the Maori Language Commission (Te Taura Whiri i te Reo Maori) and legislation of Maori as an official language of New Zealand in 1987.

year: 2007