Highly Luminescent Lanthanide Chirality Probes

The chirality of biological systems can be probed using highly emissive lanthanide complexes with the aid of circularly polarised luminescence and emission spectroscopy. Such chirality probes can be synthesised through the incorporation of a remote chiral centre within the ligand framework, which can preferentially stabilise a particular stereoisomer giving an enantiopure complex of well-defined helicity. Alternatively, lanthanide chirality probes can be derived from achiral or dynamically racemic ligands, where the selective induction of a CPL signal can be monitored as a function of the nature and concentration of a selected chiral analyte. A series of chiral lanthanide complexes has been synthesised. Each complex is based on an amide substituted 1,4,7-triazacyclononane system derived from either R-(+) or S-(-)-α-methylbenzyl amine. The stereochemistry of the amide moiety controls the helicity of the complex, and one major diastereoisomer is formed for each lanthanide metal. The absolute stereochemistry of the major diastereoisomer was determined by X-ray crystallography (S-Δ-λλλ and R-Λ-δδδ). Inclusion of an aryl-alkynyl chromophore generated complexes that exhibited large extinction coefficients (up to 55,000 M-1 cm-1) and high quantum yields (up to 37%) in water. A second set of bright Eu (III) complexes has been prepared based on an achiral heptadentate ligand system, which vary in the nature of the pyridyl donor (phosphinate, carboxylate and amide). The binding of a number of chiral acids including lactate, mandelate and cyclohexylhydroxyacetate was monitored by a change in the emission spectrum and the induction of strong CPL. Empirical analysis of the ΔJ = 4 region of each of the Eu (III) complexes allows an assignment of the complex-anion adducts as R-Δ and S-Λ. Furthermore, variations in the sign and magnitude of CPL allow the enantiomeric purity of samples with unknown enantiomeric composition to be assessed. Finally, several dynamically racemic lanthanide chirality probes have been synthesised and characterised. Induced CPL has been assessed, which arises as a result of the change in complex constitution upon binding to important chiral biomolecules such as, sialic acid, O-phosphono-amino acids and peptides and oleoyl-L-lysophosphatidic acid (LPA). This work presents the first example of induced CPL in the detection of cancer biomarkers, sialic acid and LPA, and demonstrates the utility of this class of dynamically racemic Eu (III) complexes as chirality probes

Communication intervention for individuals with Down syndrome: Systematic review and meta-analysis

A systematic review was conducted to identify effective intervention strategies for communication in individuals with Down syndrome. We updated and extended previous reviews by examining: (1) participant characteristics; (2) study characteristics; (3) characteristics of effective interventions (e.g., strategies and intensity); (4) whether interventions are tailored to the Down syndrome behavior phenotype; and (5) the effectiveness (i.e., percentage non-overlapping data and Cohen’s d) of interventions. Thirty-seven studies met inclusion criteria. The majority of studies used behaviour analytic strategies and produced moderate gains in communication targets. Few interventions were tailored to the needs of the Down syndrome behaviour phenotype. The results suggest that behaviour analytic strategies are a promising approach and future research should focus on replicating the effects of these interventions with greater methodological rigor

Studying Treatment Intensity: Lessons from Two Preliminary Studies

Determining how best to meet the needs of learners with Down syndrome requires an approach to intervention delivered at some level of intensity. How treatment intensity affects learner acquisition, maintenance, and generalization of skills can help optimize the efficiency and cost effectiveness of interventions. There is a growing body of research on the effects of treatment intensity but almost no systematic study of it with children with Down syndrome, providing little guidance about how to approach the study of intensity. In two preliminary studies we manipulated different aspects of the dose of treatment intensity and measured effects on skill acquisition using single-subject experimental designs. Intensity varied in terms of number of opportunities per session, session duration, and spacing of opportunities (inter-stimulus interval). Matched responses within a skill area were randomly assigned to a level of intensity and acquisition was compared. Results reveal lessons about what aspects of intensity to manipulate and how, selecting experimental designs, measuring multiple outcomes, and the influence of learner characteristics. These lessons highlight directions for future approaches to tease apart the relative contributions of different aspects of intensity on skill acquisition and determine the most effective intensity of early intervention for children with Down syndrome

Repetitive Behavior in Children with Down Syndrome: Functional Analysis and Intervention

Children with Down syndrome frequently display repetitive behavior including unusual routines, rituals, and stereotypy. Literature on intervention for repetitive behavior in individuals with Down syndrome frequently includes aversive procedures and interventions not informed by functional assessments. We used an analogue functional analysis to evaluate reinforcers maintaining repetitive behavior in 3 children with Down syndrome. Following identification of automatic functions, we used an ABAB design and a multiple-baseline design to demonstrate the effectiveness of differential reinforcement of other behavior in reducing repetitive behavior. DRO was effective in decreasing repetitive behavior and, for one participant, repetitive behavior remained low at 1, 2, and 3-month follow-up sessions. This study extends current functional analysis methodologies to decrease repetitive behavior for learners with Down syndrome

Infinitely many virtual geometric triangulations

We prove that every cusped hyperbolic 3-manifold has a finite cover admitting infinitely many geometric ideal triangulations. Furthermore, every long Dehn filling of one cusp in this cover admits infinitely many geometric ideal triangulations. This cover is constructed in several stages, using results about separability of peripheral subgroups and their double cosets, in addition to a new conjugacy separability theorem that may be of independent interest. The infinite sequence of geometric triangulations is supported in a geometric submanifold associated to one cusp, and can be organized into an infinite trivalent tree of Pachner moves.Comment: 31 pages 4 figures, version 2 removes some typos and has minor changes in exposition. This paper has been accepted for publication by the Journal of Topolog

Gone but not forgotten : the (re-)making of diaspora strategies

This review article summarises the literature on the relations between states and their diaspora. Policy makers are struggling to know how best to respond to and possibly harness the potential of kindred communities abroad. The article outlines a wide spectrum of policy initiatives and categorises them into three groups: economic, political and socio-cultural. Five economic, four political and two social-cultural factors are discussed as are the wide variety of implementation strategy evident in different jurisdictions. Though the concentration is on Asia, examples are chosen worldwide. Academically, the article identifies empirical and conceptual deficiencies in studies on diaspora strategies.Non peer reviewe

An Electromyography Study of Muscular Endurance during the Posterior Shoulder Endurance Test

The primary purpose was to determine if there is a difference between the median frequency slopes of 5 posterior shoulder muscles during the initial portion of the Posterior Shoulder Endurance Test (PSET) at the 90⁰ and 135⁰ shoulder abduction positions. Fifty-five healthy volunteers (31 females) participated. The median frequency of the posterior deltoid (PD), upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and infraspinatus (INF) was measured during the PSET at 90⁰ and 135⁰ of shoulder abduction. External torque of 13±1 Nm was used for females and 21±1 Nm for males. A fixed effect multi-variable regression model was used to investigate the median frequency slopes. Males and females were analyzed separately. Median frequency slopes demonstrated fatigue in all 5 of the muscles. The PD fatigued greater than the UT in males (p=0.0215) and greater than the LT in females (p=0.008). The time to task failure (TTF) was greater at 90° than 135° for females and males (p=0.016; p=0.0193) respectively. The PSET causes fatigue in all of the muscles that were tested, with the PD fatiguing at a greater rate compared to one muscle for each sex. This investigation supports using TTF as a clinical measure of shoulder girdle endurance at 90° shoulder abduction

Infinitely many virtual geometric triangulations

We prove that every cusped hyperbolic 3-manifold has a finite cover admitting infinitely many geometric ideal triangulations. Furthermore, every long Dehn filling of one cusp in this cover admits infinitely many geometric ideal triangulations. This cover is constructed in several stages, using results about separability of peripheral subgroups and their double cosets, in addition to a new conjugacy separability theorem that may be of independent interest. The infinite sequence of geometric triangulations is supported in a geometric submanifold associated to one cusp, and can be organized into an infinite trivalent tree of Pachner moves.Mathematic

E151 (sym15), A Pleiotropic Mutant of Pea (Pisum sativum L.), Displays Low Nodule Number, Enhanced Mycorrhizae, Delayed Lateral Root Emergence, and High Root Cytokinin Levels

In legumes, the formation of rhizobial and mycorrhizal root symbioses is a highly regulated process which requires close communication between plant and microorganism. Plant mutants that have difficulties establishing symbioses are valuable tools for unravelling the mechanisms by which these symbioses are formed and regulated. Here E151, a mutant of Pisum sativum cv. Sparkle, was examined to characterize its root growth and symbiotic defects. The symbioses in terms of colonization intensity, functionality of micro-symbionts, and organ dominance were compared between the mutant and wild type. The endogenous cytokinin (CK) and abscisic acid (ABA) levels and the effect of the exogenous application of these two hormones were determined. E151 was found to be a low and delayed nodulator, exhibiting defects in both the epidermal and cortical programmes though a few mature and functional nodules develop. Mycorrhizal colonization of E151 was intensified, although the fungal functionality was impaired. Furthermore, E151 displayed an altered lateral root (LR) phenotype compared with that of the wild type whereby LR emergence is initially delayed but eventually overcome. No differences in ABA levels were found between the mutant and the wild type, but non-inoculated E151 exhibited significantly high CK levels. It is hypothesized that CK plays an essential role in differentially mediating the entry of the two micro-symbionts into the cortex; whereas it would inhibit the entry of the rhizobia in that tissue, it would promote that of the fungus. E151 is a developmental mutant which may prove to be a useful tool in further understanding the role of hormones in the regulation of beneficial root symbioses