Nigrocin-2 peptides from Chinese Odorrana frogs – integration of UPLC/MS/MS with molecular cloning in amphibian skin peptidome analysis

Peptidomics is a powerful set of tools for the identification, structural elucidation and discovery of novel regulatory peptides and for monitoring the degradation pathways of structurally and catalytically important proteins. Amphibian skin secretions, arising from specialized granular glands, often contain complex peptidomes containing many components of entirely novel structure and unique site-substituted analogues of known peptide families. Following the discovery that the granular gland transcriptome is present in such secretions in a PCR-amenable form, we designed a strategy for peptide structural characterization involving the integration of ‘shotgun’ cloning of cDNAs encoding peptide precursors, deduction of putative bioactive peptide structures, and confirmation of these structures using tandem MS/MS sequencing. Here, we illustrate this strategy by means of elucidation of the primary structures of nigrocin-2 homologues from the defensive skin secretions of four species of Chinese Odorrana frogs, O. schmackeri, O. livida, O. hejiangensis and O. versabilis. Synthetic replicates of the peptides were found to possess antimicrobial activity. Nigrocin-2 peptides occur widely in the skin secretions of Asian ranid frogs and in those of the Odorrana group, and are particularly well-represented and of diverse structure in some species. Integration of the molecular analytical technologies described provides a means for rapid structural characterization of novel peptides from complex natural libraries in the absence of systematic online database information.

Domain Bundle Boundaries in Single Crystal BaTiO3 Lamellae: Searching for Naturally Forming Dipole Flux-Closure / Quadrupole Chains

Naturally occurring boundaries between bundles of 90o stripe domains, which form in BaTiO3 lamellae on cooling through the Curie Temperature, have been characterised using both piezoresponse force microscopy (PFM) and scanning transmission electron microscopy (STEM). Detailed interpretation of the dipole configurations present at these boundaries (using data taken from PFM) shows that, in the vast majority of cases, they are composed of simple zigzag 180° domain walls. Topological information from STEM shows that, occasionally, domain bundle boundaries can support chains of dipole flux closure and quadrupole nanostructures, but these kinds of boundaries are comparatively rare; when such chains do exist, it is notable that singularities at the cores of the dipole structures are avoided. The symmetry of the boundary shows that diads and centres of inversion exist at positions where core singularities should have been expected.

Managing time: integration of care and paid work amongst low income families and the role of the United Kingdom’s tax credit system

Under the New Labour Governments in the UK, successive reforms of the tax and benefit system sought to improve the financial benefits of paid work. Drawing on two waves of qualitative interviews with low-income working families this article examines the role of the UK tax credit system in shaping decisions about employment and unpaid care work. The article suggests that the financial support provided for lone parent participants by the tax credit system enhanced their temporal autonomy, permitting participation in paid work to align more closely with temporally situated notions of parental responsibility for caring. For couple families however, parental perceptions of responsibility for pre-school children, along with childcare constraints and the structure of the tax credit system served to constrain the autonomy of the main carer and implicitly encourage a gendered specialisation in caring or employment.

Modeling Frequency-Dependent Boundaries as Digital Impedance Filters in FDTD and K-DWM Room Acoustics Simulations

A new method for modeling-frequency-dependent boundaries in finite-difference time-domain (FDTD) and Kirchhoff variable digital waveguide mesh (K-DWM) room acoustics simulations is presented. The proposed approach allows the direct incorporation of a digital impedance filter (DIF) in the Multidimensional (2D or 3D) FDTD boundary model of a locally reacting surface. An explicit boundary update equation is obtained by carefully constructing a Suitable recursive formulation. The method is analyzed in terms of pressure wave reflectance for different wall impedance filters and angles of incidence. Results obtained from numerical experiments confirm the high accuracy of the proposed digital impedance filter boundary model, the reflectance of which matches locally reacting surface (LRS) theory closely. Furthermore a numerical boundary analysis (NBA) formula is provided as a technique for an analytic evaluation of the numerical reflectance of the proposed digital impedance filter boundary formulation.

Dilemmatic human-animal boundaries in Britain and Romania: Post-materialist and materialist dehumanization

Theories of dehumanization generally assume a single clear-cut, value-free and non-dilemmatic boundary between the categories 'human' and 'animal'. The present study highlights the relevance of dilemmas involved in drawing that boundary. In six focus groups carried out in Romania and Britain, 42 participants were challenged to think about dilemmas pertaining to animal and human life. Four themes were identified: rational autonomy, sentience, speciesism and maintaining materialist and post-materialist values. Sentience made animals resemble humans, while humans' rational autonomy made them distinctive. Speciesism underlay the human participants' prioritization of their own interests over those of animals, and a conservative consensus that the existing social system could not change supported this speciesism when it was challenged. Romanian participants appealed to Romania's lack of modernity and British participants to Britain's modernity to justify such conservatism. The findings suggest that the human-animal boundary is not essentialized; rather it seems that such boundary is constructed in a dilemmatic and post hoc way. Implications for theories of dehumanization are discussed.

The rhetoric of acculturation: When integration means assimilation

Viewing traditional acculturation literature through a social constructionist lens, the present paper identifies a number of limitations with this research. A discourse analytic approach to acculturation is offered as a means of addressing some of these issues. Drawing on examples taken from British print media debate surrounding the issue of faith schooling in the UK, an analysis is presented which illustrates the manner in which, though optimally positioned within acculturative moral hierarchies directed towards the legitimization of both pro- and anti-faith schooling debates, integration rhetoric often conceals the (re-)production of a more implicit assimilationism. Findings are discussed in terms of their implications for hegemonically structured acculturative power relations. This exploratory analysis provides the basis for reflection on the benefits of a discursive approach to acculturation. Moreover, the dependence of integrationist discourse on a series of socio-spatial resources is considered and, following on from Dixon and Durrheim's (2000) discursive re-conceptualization of place-identity, is taken to signify the need for a more environmentally 'grounded' approach to acculturation.

Cold War Along the Emerald Curtain: Rural Boundaries in a Contested Border Zone

This paper examines how anxieties about ethnic identity proliferate as state borders begin to shift and open in response to accelerating possibilities of cross-border cooperation. As the border becomes more porous, social and cultural boundaries become marked in other ways, spatially re-scaled to reflect new uncertainties consequent upon border change. Using an example from the Irish land border, the paper traces how national space is re-imagined and re-placed in the everyday practices of residents in a violent border zone from which the state is ostensibly retreating. It shows that communal division is as sharply drawn as ever at a time when the ‘visibility’ of the state border itself is beginning to diminish.