title: Identification of central mechanisms underlying statin-induced changes in consummatory behaviour in rats

authors: Isgrove, Kiriana

subjects: simvastatin

abstract: Simvastatin is a cholesterol lowering statin whose adverse effects include an increase in appetite and, consequently, obesity. This is counterproductive to the otherwise beneficial outcomes of simvastatin on metabolic and cardiovascular health. The mechanisms underlying simvastatin-induced hyperphagia are unknown. This thesis investigated by using a laboratory rat model whether central mechanisms contribute to simvastatin-induced increase in appetite. First, the effect of intracerebroventricularly (ICV) administered simvastatin on the energy-driven intake of ‘bland’ chow, and on reward-motivated consumption of palatable solutions, was determined. The data indicate that ICV simvastatin moderately increases ingestion of energy-dense chow, but it does not affect consumption of calorie-dilute and non-caloric palatable sucrose or saccharin solutions. It suggests that simvastatin acting directly at the brain level elevates intake of energy, while being ineffective in stimulating eating for reward. Surprisingly, rats injected ICV with this statin consume also significantly more water after water deprivation, which points to a relationship between centrally acting simvastatin and thirst-related processing. In the second part of this project, the effect of the orexigenic dose of ICV simvastatin on neuronal activation in consumption-related hypothalamic sites was investigated. Simvastatin elevated c-Fos immunoreactivity, which serves as a marker of neuronal activation, in the arcuate and paraventricular nuclei, two sites that have a profound influence on the regulation of energy intake and energy balance, as well as affect water balance. It can be concluded that simvastatin increases intake of energy and of water, and that it likely exerts its action through the hypothalamic paraventricular and arcuate nuclei.

text: Identification of central mechanisms underlying statin-induced changes in consummatory behaviour in rats Simvastatin is a cholesterol lowering statin whose adverse effects include an increase in appetite and, consequently, obesity. This is counterproductive to the otherwise beneficial outcomes of simvastatin on metabolic and cardiovascular health. The mechanisms underlying simvastatin-induced hyperphagia are unknown. This thesis investigated by using a laboratory rat model whether central mechanisms contribute to simvastatin-induced increase in appetite. First, the effect of intracerebroventricularly (ICV) administered simvastatin on the energy-driven intake of ‘bland’ chow, and on reward-motivated consumption of palatable solutions, was determined. The data indicate that ICV simvastatin moderately increases ingestion of energy-dense chow, but it does not affect consumption of calorie-dilute and non-caloric palatable sucrose or saccharin solutions. It suggests that simvastatin acting directly at the brain level elevates intake of energy, while being ineffective in stimulating eating for reward. Surprisingly, rats injected ICV with this statin consume also significantly more water after water deprivation, which points to a relationship between centrally acting simvastatin and thirst-related processing. In the second part of this project, the effect of the orexigenic dose of ICV simvastatin on neuronal activation in consumption-related hypothalamic sites was investigated. Simvastatin elevated c-Fos immunoreactivity, which serves as a marker of neuronal activation, in the arcuate and paraventricular nuclei, two sites that have a profound influence on the regulation of energy intake and energy balance, as well as affect water balance. It can be concluded that simvastatin increases intake of energy and of water, and that it likely exerts its action through the hypothalamic paraventricular and arcuate nuclei.

year: 2017

title: Increasing plate heat exchanger thermal duty: an industrial case study

authors: Walmsley, Timothy Gordon

abstract: The design and rating of Plate Heat Exchangers (PHE) entails the classic engineering trade-off between heat transfer and pressure drop. Countless studies have characterised the thermal and hydraulic performance of a wide variety of PHE and formulated fundamental correlations for fluid film coefficients, h, and friction factor, f [1]. However such academic results appear seldom to inform the site engineer regarding the best design and operating practices of heat exchangers in the New Zealand dairy industry. In this paper we present the thermal analysis of a site hot water preheater located at one of New Zealand’s largest dairy factories. Using fundamental heat exchanger theory, the analysis also looks at how to increase the heat exchanger’s duty and the coupled effect on pressure drop and pumping cost.

text: Increasing plate heat exchanger thermal duty: an industrial case study The design and rating of Plate Heat Exchangers (PHE) entails the classic engineering trade-off between heat transfer and pressure drop. Countless studies have characterised the thermal and hydraulic performance of a wide variety of PHE and formulated fundamental correlations for fluid film coefficients, h, and friction factor, f [1]. However such academic results appear seldom to inform the site engineer regarding the best design and operating practices of heat exchangers in the New Zealand dairy industry. In this paper we present the thermal analysis of a site hot water preheater located at one of New Zealand’s largest dairy factories. Using fundamental heat exchanger theory, the analysis also looks at how to increase the heat exchanger’s duty and the coupled effect on pressure drop and pumping cost.

year: 2013-11-25

title: Te whakaihonga: He tikanga tapahi makawe i te ao Māori

authors: McDonald, Rangihurihia Ann

subjects: Tapahi makawe

abstract: E ai ki te Māori, mai anō i a Māui Pōtiki, kua tapahia e te pouaru, e te kirimate, ngō rātou makawe i te tangihanga. He reureu, he tiotio, he pakipaki taha ngētehi o ngā tohu weriweri nei, i tauawhi, i whakaū i te aroha ki te mate. I ngētehi wā, he whakamaumahara, he take whakariri i te ngākau, he utu i te tangi kino o te manawa. Mutu kau ana te tangihanga, ko te heuenga hoki i te whare tauā, ki te wai whakaika. Ko ngētehi take ngēnei o te tapahi makawe a te kirimate, otirā, ko te tino whāinga o tēnei tuhinga whakapae. He whakapono makawe anō i whakaemingia, nā te rangahau mātātuhi, ko ngā pūrākau, ngā mōteatea, ngā whakataukī anō hoki a ngā tūpuna. He tirohanga kaumātua i kohikohingia nā roto mai o te uiui. Waiho mai ana ko ngā tikanga tawhito mō te tapahi i te uru tapu o te tangata, ki te ao tūroa.

text: Te whakaihonga: He tikanga tapahi makawe i te ao Māori E ai ki te Māori, mai anō i a Māui Pōtiki, kua tapahia e te pouaru, e te kirimate, ngō rātou makawe i te tangihanga. He reureu, he tiotio, he pakipaki taha ngētehi o ngā tohu weriweri nei, i tauawhi, i whakaū i te aroha ki te mate. I ngētehi wā, he whakamaumahara, he take whakariri i te ngākau, he utu i te tangi kino o te manawa. Mutu kau ana te tangihanga, ko te heuenga hoki i te whare tauā, ki te wai whakaika. Ko ngētehi take ngēnei o te tapahi makawe a te kirimate, otirā, ko te tino whāinga o tēnei tuhinga whakapae. He whakapono makawe anō i whakaemingia, nā te rangahau mātātuhi, ko ngā pūrākau, ngā mōteatea, ngā whakataukī anō hoki a ngā tūpuna. He tirohanga kaumātua i kohikohingia nā roto mai o te uiui. Waiho mai ana ko ngā tikanga tawhito mō te tapahi i te uru tapu o te tangata, ki te ao tūroa.

year: 2011