title: Feed-forward mechanisms: Addiction-like behavioral and molecular adaptations in overeating

authors: Alsiö, Johan

subjects: obesity

abstract: Food reward, not hunger, is the main driving force behind eating in the modern obesogenic environment. Palatable foods, generally calorie-dense and rich in sugar/fat, are thus readily overconsumed despite the resulting health consequences. Important advances have been made to explain mechanisms underlying excessive consumption as an immediate response to presentation of rewarding tastants. However, our understanding of long-term neural adaptations to food reward that oftentimes persist during even a prolonged absence of palatable food and contribute to the reinstatement of compulsive overeating of high-fat high-sugar diets, is much more limited. Here we discuss the evidence from animal and human studies for neural and molecular adaptations in both homeostatic and non-homeostatic appetite regulation that may underlie the formation of a “feed-forward” system, sensitive to palatable food and propelling the individual from a basic preference for palatable diets to food craving and compulsive, addiction-like eating behavior.

text: Feed-forward mechanisms: Addiction-like behavioral and molecular adaptations in overeating Food reward, not hunger, is the main driving force behind eating in the modern obesogenic environment. Palatable foods, generally calorie-dense and rich in sugar/fat, are thus readily overconsumed despite the resulting health consequences. Important advances have been made to explain mechanisms underlying excessive consumption as an immediate response to presentation of rewarding tastants. However, our understanding of long-term neural adaptations to food reward that oftentimes persist during even a prolonged absence of palatable food and contribute to the reinstatement of compulsive overeating of high-fat high-sugar diets, is much more limited. Here we discuss the evidence from animal and human studies for neural and molecular adaptations in both homeostatic and non-homeostatic appetite regulation that may underlie the formation of a “feed-forward” system, sensitive to palatable food and propelling the individual from a basic preference for palatable diets to food craving and compulsive, addiction-like eating behavior.

year: 2012

title: Exploring the Lewis basicity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] on metal substrates by electrospray mass spectrometry. Synthesis, characterization and structural studies of new platinum selenido phosphine complexes containing the {Pt₂Se₂} core

authors: Yeo, Jeremy S.L.

subjects: chemistry

abstract: Electrospray Mass Spectrometry (ESMS) has been used as a tool to probe the reactivity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] with metal substrates, which lead to the formation of charged coordination complexes via loss of halides or other labile ligands. Among the numerous metal substrates used in the displacement reactions are Au(anpy)Cl₂ (anpy = cyclometallated 2-anilinopyridyl), HgPhCl and Pb(NO₃)₂. Acid titration on the Lewis basic metalloligand leads to the identification and isolation of the doubly-protonated species, [Pt₂(μ-SeH)₂(PPh₃)₄]²⁺, whose sulfide analogue cannot be isolated. A three-step strategy is employed in the use of ESMS as a probe: (i) preliminary screening of the metalloligand with an array of acidic main group and transition group metal compounds, (ii) identification of potentially stable and isolable products formed in situ based on ion distribution and simulated isotope patterns and (iii) promising reactions are repeated on a laboratory scale, and target products are isolated and characterized. X-Ray diffraction studies have been performed on single crystals of [Pt₂(μ-SeH)₂(PPh₃)₄][ClO₄]₂, [Pt₂(μ₃-Se)₂(PPh₃)₄(CdCl₂)] and {Pt₂(μ₃-Se)₂(PPh₃)₄[Pb(NO₃)]}{NO₃}. These results suggested that in general a parallel chemistry can be developed on the intermetallic selenides as on the sulfides. However, there are chemical and structural differences which are highlighted in this paper.

text: Exploring the Lewis basicity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] on metal substrates by electrospray mass spectrometry. Synthesis, characterization and structural studies of new platinum selenido phosphine complexes containing the {Pt₂Se₂} core Electrospray Mass Spectrometry (ESMS) has been used as a tool to probe the reactivity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] with metal substrates, which lead to the formation of charged coordination complexes via loss of halides or other labile ligands. Among the numerous metal substrates used in the displacement reactions are Au(anpy)Cl₂ (anpy = cyclometallated 2-anilinopyridyl), HgPhCl and Pb(NO₃)₂. Acid titration on the Lewis basic metalloligand leads to the identification and isolation of the doubly-protonated species, [Pt₂(μ-SeH)₂(PPh₃)₄]²⁺, whose sulfide analogue cannot be isolated. A three-step strategy is employed in the use of ESMS as a probe: (i) preliminary screening of the metalloligand with an array of acidic main group and transition group metal compounds, (ii) identification of potentially stable and isolable products formed in situ based on ion distribution and simulated isotope patterns and (iii) promising reactions are repeated on a laboratory scale, and target products are isolated and characterized. X-Ray diffraction studies have been performed on single crystals of [Pt₂(μ-SeH)₂(PPh₃)₄][ClO₄]₂, [Pt₂(μ₃-Se)₂(PPh₃)₄(CdCl₂)] and {Pt₂(μ₃-Se)₂(PPh₃)₄[Pb(NO₃)]}{NO₃}. These results suggested that in general a parallel chemistry can be developed on the intermetallic selenides as on the sulfides. However, there are chemical and structural differences which are highlighted in this paper.

year: 2002

title: The piano as cultural symbol in colonial New Zealand

authors: Moffat, Kirstine

subjects: piano

abstract: The piano was an important cultural symbol in colonial New Zealand, yet although there is a significant body of international scholarship on the social and cultural history of the instrument in Britain, America, Canada, Norway, Spain and India there is a dearth of scholarly criticism relating to New Zealand. Research to redress this absence has revealed that the piano was central to settler culture, demonstrating a migrant desire to replicate the known and familiar but also highlighting settler innovations and an emerging nationalism. International connections between New Zealand, Britain, Western Europe, America and Australia are also apparent in relation to migrant patterns, the importation of instruments and sheet music and networks of musical performance and study. The instrument played a role in the complex dynamic of cultural encounter between Maori and settler, with an initial indigenous negativity and bemusement giving way to an interest in the piano and an appropriation of the instrument into Maori cultural contexts and spaces, including the marae. Prevailing perceptions of gender roles and identity are also challenged by research on the piano. Likewise, an examination of piano and class reveals that the instrument was popular with New Zealanders from all socio-economic backgrounds.

text: The piano as cultural symbol in colonial New Zealand The piano was an important cultural symbol in colonial New Zealand, yet although there is a significant body of international scholarship on the social and cultural history of the instrument in Britain, America, Canada, Norway, Spain and India there is a dearth of scholarly criticism relating to New Zealand. Research to redress this absence has revealed that the piano was central to settler culture, demonstrating a migrant desire to replicate the known and familiar but also highlighting settler innovations and an emerging nationalism. International connections between New Zealand, Britain, Western Europe, America and Australia are also apparent in relation to migrant patterns, the importation of instruments and sheet music and networks of musical performance and study. The instrument played a role in the complex dynamic of cultural encounter between Maori and settler, with an initial indigenous negativity and bemusement giving way to an interest in the piano and an appropriation of the instrument into Maori cultural contexts and spaces, including the marae. Prevailing perceptions of gender roles and identity are also challenged by research on the piano. Likewise, an examination of piano and class reveals that the instrument was popular with New Zealanders from all socio-economic backgrounds.

year: 2009