High-definition self-assemblies driven by the hydrophobic effect: synthesis and properties of a supramolecular nanocapsule

High definition self-assemblies, those that possess order at the molecular level, are most commonly made from subunits possessing metals and metal coordination sites, or groups capable of partaking in hydrogen bonding. In other words, enthalpy is the driving force behind the free energy of assembly. The hydrophobic effect engenders the possibility of (nominally) relying not on enthalpy but entropy to drive assembly. Towards this idea, we describe how template molecules can trigger the dimerization of a cavitand in aqueous solution, and in doing so are encapsulated within the resulting capsule. Although not held together by (enthalpically) strong and directional non-covalent forces, these capsules possess considerable thermodynamic and kinetic stability. As a result, they display unusual and even unique properties. We discuss some of these, including the use of the capsule as a nanoscale reaction chamber and how they can bring about the separation of hydrocarbon gases

Inferring Kangaroo Phylogeny from Incongruent Nuclear and Mitochondrial Genes

The marsupial genus Macropus includes three subgenera, the familiar large grazing kangaroos and wallaroos of M. (Macropus) and M. (Osphranter), as well as the smaller mixed grazing/browsing wallabies of M. (Notamacropus). A recent study of five concatenated nuclear genes recommended subsuming the predominantly browsing Wallabia bicolor (swamp wallaby) into Macropus. To further examine this proposal we sequenced partial mitochondrial genomes for kangaroos and wallabies. These sequences strongly favour the morphological placement of W. bicolor as sister to Macropus, although place M. irma (black-gloved wallaby) within M. (Osphranter) rather than as expected, with M. (Notamacropus). Species tree estimation from separately analysed mitochondrial and nuclear genes favours retaining Macropus and Wallabia as separate genera. A simulation study finds that incomplete lineage sorting among nuclear genes is a plausible explanation for incongruence with the mitochondrial placement of W. bicolor, while mitochondrial introgression from a wallaroo into M. irma is the deepest such event identified in marsupials. Similar such coalescent simulations for interpreting gene tree conflicts will increase in both relevance and statistical power as species-level phylogenetics enters the genomic age. Ecological considerations in turn, hint at a role for selection in accelerating the fixation of introgressed or incompletely sorted loci. More generally the inclusion of the mitochondrial sequences substantially enhanced phylogenetic resolution. However, we caution that the evolutionary dynamics that enhance mitochondria as speciation indicators in the presence of incomplete lineage sorting may also render them especially susceptible to introgression.This work has been supported by Australian Research Council grants to MJP (DP07745015) and MB (FT0991741). The website for the funder is www.arc.gov.au. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

A qualitative study of primary care professionals’ views of case finding for depression in patients with diabetes or coronary heart disease in the UK

<p>Background Routinely conducting case finding (also commonly referred to as screening) in patients with chronic illness for depression in primary care appears to have little impact. We explored the views and experiences of primary care nurses, doctors and managers to understand how the implementation of case finding/screening might impact on its effectiveness.</p> <p>Methods Two complementary qualitative focus group studies of primary care professionals including nurses, doctors and managers, in five primary care practices and five Community Health Partnerships, were conducted in Scotland.</p> <p>Results We identified several features of the way case finding/screening was implemented that may lead to systematic under-detection of depression. These included obstacles to incorporating case finding/screening into a clinical review consultation; a perception of replacing individualised care with mechanistic assessment, and a disconnection for nurses between management of physical and mental health. Far from being a standardised process that encouraged detection of depression, participants described case finding/screening as being conducted in a way which biased it towards negative responses, and for nurses, it was an uncomfortable task for which they lacked the necessary skills to provide immediate support to patients at the time of diagnosis.</p> <p>Conclusion The introduction of case finding/screening for depression into routine chronic illness management is not straightforward. Routinized case finding/screening for depression can be implemented in ways that may be counterproductive to engagement (particularly by nurses), with the mental health needs of patients living with long term conditions. If case finding/screening or engagement with mental health problems is to be promoted, primary care nurses require more training to increase their confidence in raising and dealing with mental health issues and GPs and nurses need to work collectively to develop the relational work required to promote cognitive participation in case finding/screening.</p&gt

Uniaxial magnetocrystalline anisotropy in CaRuO3{\rm CaRuO_3}

${\rm CaRuO_3}$ is a paramagnetic metal and since its low temperature resistivity is described by $\rho=\rho_0+AT^\gamma$ with $\gamma \sim 1.5$, it is also considered a non-Fermi liquid (NFL) metal. We have performed extensive magnetoresistance and Hall effect measurements of untwinned epitaxial films of ${\rm CaRuO_3}$. These measurements reveal that ${\rm CaRuO_3}$ exhibits uniaxial magnetocrystalline anisotropy. In addition, the low-temperature NFL behavior is most effectively suppressed when a magnetic field is applied along the easy axis, suggesting that critical spin fluctuations, possibly due to proximity of a quantum critical phase transition, are related to the NFL behavior.Comment: 7 figure

Botulinum toxin injections as a method for chemically denervating skeletal muscle to test functional hypotheses: a pilot study in Lepomis cyanellus

In this study, we demonstrate that botulinum toxin can be used to chemically denervate muscles to test functional hypotheses. We injected research-grade type A botulinum toxin complex into pectoral fin abductors (abductor superficialis) of green sunfish (Lepomis cyanellus) to determine whether chemical denervation would eliminate the ability of a particular muscle to contribute to overall pectoral fin movements. Reduction of target muscle activity occurred within 8 d of the injection, and paralysis was confirmed using electromyography. No paralysis was seen in the adjacent muscles (abductor profundus) or in positive controls (saline injections). Paralysis occurred more slowly and at lower doses than previously documented for mammals. However, botulinum toxin complex (500 kDa) was used here, whereas previous studies have used purified toxin (150 kDa). Therefore, differences in physiological responses between fish and mammals cannot yet be distinguished from differences caused by the toxin type. However, we note that the toxin complex is less likely to diffuse across muscle fascia (because it is large), which should minimize paralytic effects on adjacent muscles. We suggest that botulinum toxin holds great promise as a chemical denervation agent in functional studies of animal locomotion and feeding behaviors