title: Electromagnetic Techniques to Minimize the Risk of Hazardous Local Heating around Medical Implant Electrodes during MRI Scanning

authors: McCabe, Steven Owen

abstract: Magnetic Resonance Imaging (MRI) scans are contraindicated for many patients with medical implants. We establish the circumstances that cause, and the resistances required to ameliorate and to eliminate dangerous levels of MRI-induced heating that occur at the exposed, distal end of an electrical lead implanted in tissue. Simulated predictions are compared with measurements made at 128 MHz in a 3-Tesla MRI machine. A low resistance at kilohertz frequencies is sought by implant makers, in contrast with the high resistance demanded for safety. The practicality of presently-developed strategies to prevent tissue damage is brought into question. We examine the extent to which skin-depth and transmission-line properties can be manipulated to improve safety.

text: Electromagnetic Techniques to Minimize the Risk of Hazardous Local Heating around Medical Implant Electrodes during MRI Scanning Magnetic Resonance Imaging (MRI) scans are contraindicated for many patients with medical implants. We establish the circumstances that cause, and the resistances required to ameliorate and to eliminate dangerous levels of MRI-induced heating that occur at the exposed, distal end of an electrical lead implanted in tissue. Simulated predictions are compared with measurements made at 128 MHz in a 3-Tesla MRI machine. A low resistance at kilohertz frequencies is sought by implant makers, in contrast with the high resistance demanded for safety. The practicality of presently-developed strategies to prevent tissue damage is brought into question. We examine the extent to which skin-depth and transmission-line properties can be manipulated to improve safety.

year: 2015

title: Book reviews and Book notices

authors: Waikato Geological Society

abstract: Book reviews and Book notices from Volume 3, Number 2, 1969 of Earth Science Journal.

text: Book reviews and Book notices Book reviews and Book notices from Volume 3, Number 2, 1969 of Earth Science Journal.

year: 1969

title: "He taketake, he hurumanu te moana i rōhia ai": Mā te Māori ngā toronga o te motu ki whenua kē e taurima?

authors: Dewes, Kaneihana

subjects: Iwi taketake

abstract: Kai te tino ia o te tuhinga rangahau nei, he whakatōmene i te āhua kaiārahi o te Māori i ngā tūāhua hono ki ahurea kē. Mā konei e whakatau ai, e whakatūwherahia rānei ngā āhuatanga e mea ana mā te Māori ngā toronga o te motu ki whenua kē e taurima. He momo tēnei nā te Māori, i takea mai i ngā mahi pokai moana, me ngā waka i whakaterea i ngā rohenga moana o Te Moana-nui-a-Kiwa, ā, puta noa. Waihoki, he taonga tonu wā tātau kai ngā tauira o ngā tūhononga ahurea o ngā iwi taketake o te ao; he taonga anō kai waenganui i a tātau ngā whenua maha i pakanga ki rāwāhi, he tohu nui nā te ‘price of citizenship’. He momo nā te Māori te tātaki i ngā mahi whakarauora reo, waihoki, he rite tonu te noho tahi ki whenua kē i roto i te kōingo ki te whakatipu i te reo o te whenua. Mā konei, ka marohi ai te hiranga o Te Reo Māori me ngā Tikanga Māori, tēnei hiranga e tohu ana i te hua o ngā hononga ahurea ki ngā iwi taketake huri noa, kia whai hua mō Niu Tireni i ngā toronga ki whenua kē.

text: "He taketake, he hurumanu te moana i rōhia ai": Mā te Māori ngā toronga o te motu ki whenua kē e taurima? Kai te tino ia o te tuhinga rangahau nei, he whakatōmene i te āhua kaiārahi o te Māori i ngā tūāhua hono ki ahurea kē. Mā konei e whakatau ai, e whakatūwherahia rānei ngā āhuatanga e mea ana mā te Māori ngā toronga o te motu ki whenua kē e taurima. He momo tēnei nā te Māori, i takea mai i ngā mahi pokai moana, me ngā waka i whakaterea i ngā rohenga moana o Te Moana-nui-a-Kiwa, ā, puta noa. Waihoki, he taonga tonu wā tātau kai ngā tauira o ngā tūhononga ahurea o ngā iwi taketake o te ao; he taonga anō kai waenganui i a tātau ngā whenua maha i pakanga ki rāwāhi, he tohu nui nā te ‘price of citizenship’. He momo nā te Māori te tātaki i ngā mahi whakarauora reo, waihoki, he rite tonu te noho tahi ki whenua kē i roto i te kōingo ki te whakatipu i te reo o te whenua. Mā konei, ka marohi ai te hiranga o Te Reo Māori me ngā Tikanga Māori, tēnei hiranga e tohu ana i te hua o ngā hononga ahurea ki ngā iwi taketake huri noa, kia whai hua mō Niu Tireni i ngā toronga ki whenua kē.

year: 2022