title: Characterisation of Food Intake and Expression of Feeding-Related Genes in The VPA Rat Model of Autism Spectrum Disorder

authors: Laloli, Kathryn

subjects: Autism

abstract: Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting roughly 1% of the global population. Aberrant food selectivity (AFS) is a common comorbid symptom of ASD which can result in nutritional deficiencies, increased parental stress and reduced quality of life. However, alarmingly little research has been conducted investigating the nature and the underlying neurophysiological mechanisms of AFS in ASD. This study attempts to determine whether the VPA rat model of ASD exhibits AFS when presented with various diet types. These include standard chow and water, palatable sweet tastants (sucrose, saccharin and complex liquid diet) and finally palatable high fat milks. The mRNA expression levels of oxytocin, oxytocin receptor, dynorphin and kappa-opioid receptor were then determined. These genes have previously demonstrated to be involved in both feeding and social behaviours. The VPA rats were found to consume less standard chow and water, yet increased intake of the sweet tastants was observed. Additionally, in the VPA rats’ oxytocin expression in the hypothalamus was increased, as was dynorphin expression in the hypothalamus and brainstem. Increased expression of the anorexigenic oxytocin may have resulted in the decreased intake of chow and water, and could potentially be a result of increased leptin or melanocortin levels. However, increased dynorphin expression may be responsible for the increased intake of the palatable sweet tastants, via inhibition of proopiomelanocortin or neuropeptide S. The development of effective treatments for AFS in ASD requires an understanding of the underlying neurological mechanisms. This research provides the first evidence of AFS and elevated oxytocin and dynorphin expression in the VPA rat model of ASD, thus paving the way for further research in this area.

text: Characterisation of Food Intake and Expression of Feeding-Related Genes in The VPA Rat Model of Autism Spectrum Disorder Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting roughly 1% of the global population. Aberrant food selectivity (AFS) is a common comorbid symptom of ASD which can result in nutritional deficiencies, increased parental stress and reduced quality of life. However, alarmingly little research has been conducted investigating the nature and the underlying neurophysiological mechanisms of AFS in ASD. This study attempts to determine whether the VPA rat model of ASD exhibits AFS when presented with various diet types. These include standard chow and water, palatable sweet tastants (sucrose, saccharin and complex liquid diet) and finally palatable high fat milks. The mRNA expression levels of oxytocin, oxytocin receptor, dynorphin and kappa-opioid receptor were then determined. These genes have previously demonstrated to be involved in both feeding and social behaviours. The VPA rats were found to consume less standard chow and water, yet increased intake of the sweet tastants was observed. Additionally, in the VPA rats’ oxytocin expression in the hypothalamus was increased, as was dynorphin expression in the hypothalamus and brainstem. Increased expression of the anorexigenic oxytocin may have resulted in the decreased intake of chow and water, and could potentially be a result of increased leptin or melanocortin levels. However, increased dynorphin expression may be responsible for the increased intake of the palatable sweet tastants, via inhibition of proopiomelanocortin or neuropeptide S. The development of effective treatments for AFS in ASD requires an understanding of the underlying neurological mechanisms. This research provides the first evidence of AFS and elevated oxytocin and dynorphin expression in the VPA rat model of ASD, thus paving the way for further research in this area.

year: 2017

title: Linear acoustic waves in a nonisothermal atmosphere. II. photospheric resonator model of three-minute umbral oscillations

authors: Chae, Jongchul

subjects: Science & Technology

abstract: The velocity oscillations observed in the chromosphere of sunspot umbrae resemble a resonance in that their power spectra are sharply peaked around a period of about three minutes. In order to describe the resonance that leads to the observed 3-minute oscillations, we propose the photospheric resonator model of acoustic waves in the solar atmosphere. The acoustic waves are driven by the motion of a piston at the lower boundary, and propagate in a nonisothermal atmosphere that consists of the lower layer (photosphere), where temperature rapidly decreases with height, and the upper layer (chromosphere), where temperature slowly increases with height. We have obtained the following results: (1) The lower layer (photosphere) acts as a leaky resonator of acoustic waves. The bottom end is established by the piston, and the top end by the reflection at the interface between the two layers. (2) The temperature minimum region partially reflects and partially transmits acoustic waves of frequencies around the acoustic cutoff frequency at the temperature minimum. (3) The resonance occurs in the photospheric layer at one frequency around this cutoff frequency. (4) The waves escaping the photospheric layer appear as upwardpropagating waves in the chromosphere. The power spectrum of the velocity oscillation observed in the chromosphere can be fairly well reproduced by this model. The photospheric resonator model was compared with the chromospheric resonator model and the propagating wave model.

text: Linear acoustic waves in a nonisothermal atmosphere. II. photospheric resonator model of three-minute umbral oscillations The velocity oscillations observed in the chromosphere of sunspot umbrae resemble a resonance in that their power spectra are sharply peaked around a period of about three minutes. In order to describe the resonance that leads to the observed 3-minute oscillations, we propose the photospheric resonator model of acoustic waves in the solar atmosphere. The acoustic waves are driven by the motion of a piston at the lower boundary, and propagate in a nonisothermal atmosphere that consists of the lower layer (photosphere), where temperature rapidly decreases with height, and the upper layer (chromosphere), where temperature slowly increases with height. We have obtained the following results: (1) The lower layer (photosphere) acts as a leaky resonator of acoustic waves. The bottom end is established by the piston, and the top end by the reflection at the interface between the two layers. (2) The temperature minimum region partially reflects and partially transmits acoustic waves of frequencies around the acoustic cutoff frequency at the temperature minimum. (3) The resonance occurs in the photospheric layer at one frequency around this cutoff frequency. (4) The waves escaping the photospheric layer appear as upwardpropagating waves in the chromosphere. The power spectrum of the velocity oscillation observed in the chromosphere can be fairly well reproduced by this model. The photospheric resonator model was compared with the chromospheric resonator model and the propagating wave model.

year: 2019

title: [Review of Sociocultural realities: exploring new horizons by Angus Macfarlane, Sonja Macfarlane and Melinda Webber]

authors: McNae, Rachel Elizabeth

abstract: This article reviews the book "Sociocultural realities: exploring new horizons", by Angus Macfarlane, Sonja Macfarlane and Melinda Webber, Christchurch, New Zealand, Canterbury University Press, 2015, 220 pp., $45 (softcover), ISBN 9781927145722

text: [Review of Sociocultural realities: exploring new horizons by Angus Macfarlane, Sonja Macfarlane and Melinda Webber] This article reviews the book "Sociocultural realities: exploring new horizons", by Angus Macfarlane, Sonja Macfarlane and Melinda Webber, Christchurch, New Zealand, Canterbury University Press, 2015, 220 pp., $45 (softcover), ISBN 9781927145722

year: 2017