Youth perspectives of schooling in a Northern-Ontario community

In Ontario, northern, rural youth face disadvantages due to their geographic location, as the majority of students attending high school, if not relocated to another community for their studies, must endure daily commutes ranging from 60 to 130 kilometers in order to attend classes. Yet, student-youths’ perspectives on how their geographic location influences their schooling experiences are currently absent from our understanding of educational equity in northern, rural contexts. While the literature on northern, rural education has focused almost exclusively on teacher, leadership and community perspectives, this study utilized a critical consciousness framework and interpretative phenomenology analysis with photovoice methods to explore youths’ perceptions of rural education. Five participants shared their thoughts and experiences through photovoice, individual interviews and focus groups to explore their rural educational experiences. The objective of this study was to illuminate the barriers to educational success from an equity standpoint and to explore innovative approaches with photovoice to capitalize on the strengths of these students in order to address disparities and to create opportunities for change in educational policy and practice. The findings highlighted some of the ways in which spatial, socio-cultural and physical obstacles to learning affect youth development while emphasizing how the school's climate and teachers contribute to fostering educational equity and a sense of belonging. Findings also revealed that youth encounter numerous challenges in their pursuit of secondary education. However, they manage to overcome these obstacles through the support of their schools, which serve as safe havens fostering strong relationships within the school community, or by benefiting from a flexible approach to their education. In the realm of equitable rural education, this study significantly contributes to the existing body of literature. Specifically, the present study implies that educational equity requires a lot of work. It encompasses various aspects, including a willingness to learn, cooperation, sharing of power, finding resources, harnessing creativity and imagination, and adjusting attitudes. Lastly, this study amplifies the voices of youth in the discourse surrounding educational equity in northern, rural schools

Virtual screening for high affinity guests for synthetic supramolecular receptors

The protein/ligand docking software GOLD, which was originally developed for drug discovery, has been used in a virtual screen to identify small molecules that bind with extremely high affinities (K ≈ 107 M-1) in the cavity of a cubic coordination cage in water. A scoring function was developed using known guests as a training set and modified by introducing an additional term to take account of loss of guest flexibility on binding. This scoring function was then used in GOLD to successfully identify 15 new guests and accurately predict the binding constants. This approach provides a powerful predictive tool for virtual screening of large compound libraries to identify new guests for synthetic hosts, thereby greatly simplifying and accelerating the process of identifying guests by removing the reliance on experimental trial-and-error

pH-Controlled selection between one of three guests from a mixture using a coordination cage host

We demonstrate the use of a simple pH swing to control the selection of one of three different guests from aqueous solution by a coordination cage host. Switching between different guests is based on the fact that neutral organic guests bind strongly in the cage due to the hydrophobic effect, but for acidic or basic guests, the charged (protonated or deprotonated) forms are hydrophilic and do not bind. The guests used are adamantane-1,3-dicarboxylic acid (H2A) which binds at low pH when it is neutral but not when it is deprotonated; 1-amino-adamantane (B) which binds at high pH when it is neutral but not when it is protonated; and cyclononanone (C) whose binding is not pH dependent and is therefore the default guest at neutral pH. Thus an increase in pH can reversibly switch the host between the three different bound states cageH2A (at low pH), cageC (at medium pH), and cageB (at high pH) in succession

Stepwise synthesis of mixed-metal assemblies using pre-formed Ru( ii ) ‘complex ligands’ as building blocks

Two families of heteronuclear coordination complexes have been prepared in a stepwise manner using pre-formed, kinetically inert [RuL3]2+ building blocks, in which L is a bis-bidentate bridging ligand with two pyrazole–pyridyl termini, coordinated at one end to the Ru(II) centre. These pre-formed ‘complex ligands’ – with three pendant binding sites – react with additional labile transition metal dications to complete the stepwise assembly of mixed-metal arrays in which labile [Co(II)/Cd(II)] or inert [Ru(II)] ions strictly alternate around the framework. When L = the thiophene-2,5-diyl spaced ligand Lth, the complex [Ru(Lth)3]2+ is formed in the expected 3[thin space (1/6-em)]:[thin space (1/6-em)]1 mer[thin space (1/6-em)]:[thin space (1/6-em)]fac ratio: reaction with labile Co(II) or Cd(II) ions completes formation of a heteronuclear square [Ru2Co2(Lth)6]8+ or one-dimensional coordination polymer {[CdRu(Lth)3]4+}∞, respectively. In these only the mer isomer of [Ru(Lth)3]2+ is selected by the self-assembly process, whereas the fac isomer is not used. When L = a 1,3-benzene-diyl spaced ligand (Lph), the complex ligand [Ru(Lph)3]2+ formed in the initial step is enriched in mer isomer (80–87% mer, depending on reaction conditions). Two quite different products were isolated from reaction of [Ru(Lph)3]2+ with Co(II) depending on the conditions. These are the rectangular, hexanuclear ‘open-book’ array [Ru3Co3(Lph)9]12+ which contains a 2[thin space (1/6-em)]:[thin space (1/6-em)]1 proportion of fac/mer Ru(II) metal centres; and the octanuclear cubic [Ru4Co4(Lph)12{Na(BF4)4}]13+ cage which is a new structural type containing all mer Ru(II) vertices and all fac Co(II) vertices. The cavity of this cubic cage contains a tetrahedral array of fluoroborate anions which in turn coordinate to a central Na(I) ion – an unusual example of a metal complex [Na(BF4)4]3− acting as the guest inside the cage-like metal complex [Ru4Co4(Lph)12]16+

Binding of hydrophobic guests in a coordination cage cavity is driven by liberation of 'high-energy' water

The cavity of an M8L12 cubic coordination cage can accommodate a cluster of ten water molecules in which the average number of hydrogen bonds per water molecule is 0.5 H-bonds less than it would be in the bulk solution. The presence of these 'hydrogen-bond frustrated' or 'high-energy' water molecules in the cavity results in the hydrophobic effect associated with guest binding being predominantly enthalpy-based, as these water molecules can improve their hydrogen-bonding environment on release. This contrasts with the classical form of the hydrophobic effect in which the favourable entropy change associated with release of ordered molecules from hydrophobic surfaces dominates. For several guests Van't Hoff plots showed that the free energy of binding in water is primarily enthalpy-driven. For five homologous pairs of guests related by the presence or absence of a CH2 group, the incremental changes to ∆H and T∆S for guest binding ¬- i.e. ∆∆H and T∆∆S, the difference in contributions arising from the CH2 group - are consistently 5±1 kJ mol-1 for ∆∆H and 0±1 kJ mol-1 for T∆∆S. This systematic dominance of ∆H in the binding of hydrophobic guests is consistent with the view that guest binding is dominated by release of 'high energy' water molecules into a more favourable solvation environment, as has been demonstrated recently for some members of the cucurbituril family

Binding of chemical warfare agent simulants as guests in a coordination cage: contributions to binding and a fluorescence-based response.

Cubic coordination cages act as competent hosts for several alkyl phosphonates used as chemical warfare agent simulants; a range of cage/guest structures have been determined, contributions to guest binding analysed, and a fluorescent response to guest binding demonstrated

A Quantitative Study of the Effects of Guest Flexibility on Binding Inside a Coordination Cage Host.

We have performed a systematic investigation of the effects of guest flexibility on their ability to bind in the cavity of a coordination cage host in water, using two sets of isomeric aliphatic ketones that differ only in the branching patterns of their alkyl chains. Apart from the expected increase in binding strength for C9 over C7 ketones associated with their greater hydrophobic surface area, within each isomeric set there is a clear inverse correlation between binding free energy and guest flexibility, associated with loss of conformational entropy. This can be parameterized by the number of rotatable C-C bonds in the guest, with each additional rotatable bond resulting in a penalty of around 2 kJ mol(-1) in the binding free energy, in good agreement with values obtained from protein/ligand binding studies. We used the binding data for the new flexible guests to improve the scoring function that we had previously developed that allowed us to predict binding constants of relatively rigid guests in the cage cavity using the molecular docking programme GOLD (Genetic Optimisation of Ligand Docking). This improved scoring function resulted in a significant improvement in the ability of GOLD to predict binding constants for flexible guests, without any detriment to its ability to predict binding for more rigid guests

Neurotransmitter selection by monoamine oxidase isoforms, dissected in terms of functional groups by mixed double mutant cycles

Double mutant cycles were constructed using neurotransmitters and synthetic substrates that measure their selective binding to one monoamine oxidase (MAO) enzyme isoform over another as a function of structural change. This work measures a reduction in selectivity for the MAOB isoform of 3 to 9.5 kJ mol−1 upon the addition of hydroxy functional groups to a phenethylamine scaffold. Replacement of hydroxy functional groups on the phenethylamine scaffold by hydrophobic substituents measures an increase in selectivity for MAOB of −1.1 to −6.9 kJ mol−1. The strategies presented here can be applied to the development of competitive reversible inhibitors of MAO enzymes and other targets with structurally related isoforms

Photoinduced energy- and electron-transfer from a photoactive coordination cage to bound guests.

In a coordination cage which contains an array of twelve naphthyl chromophores surrounding a central cavity, photoinduced energy or electron-transfer can occur from the chromophore array to the bound guest in supramolecular host/guest complexes