Investigation into time dependant degradation and atmospheric conditions on the wettability of nylon 6,6 which has undergone CO2 laser surface modification

Modification of the wettability of polymers has been demonstrated previously; however, it is known that the wettability modifications of these materials can degrade or vary over time. This can be seen to be crucial from a commercial point of view as this would indicate that a shelf-life has to be established. But at the same time, atmospheric parameters may affect the contact angle and must therefore be accounted for as a control variable in any long-term study of wettability. In this study four CO2 laser patterned nylon 6,6 samples with differing topographical patterns and one as-received sample were analysed over a 30 week period whilst stored in ambient air. By obtaining the characteristic contact angle every two weeks it was found that the contact angle varied erratically before ultimately increasing for all samples after the 30 weeks. White light interferometry analysis determined that the laser patterning gave rise to peak heights of up to 3 μm with roughness parameters Ra and Sa of up to 0.305 and 0.408 μm, respectively. X-ray photoelectron spectroscopy found that surface oxygen content increased by up to 7 %At. It was identified that there was a significant correlation between changes in barometric air pressure and contact angle, highlighting the need for further study to determine if this is a dominant factor

The Swift-Hohenberg equation with a nonlocal nonlinearity

It is well known that aspects of the formation of localised states in a one-dimensional Swift--Hohenberg equation can be described by Ginzburg--Landau-type envelope equations. This paper extends these multiple scales analyses to cases where an additional nonlinear integral term, in the form of a convolution, is present. The presence of a kernel function introduces a new lengthscale into the problem, and this results in additional complexity in both the derivation of envelope equations and in the bifurcation structure. When the kernel is short-range, weakly nonlinear analysis results in envelope equations of standard type but whose coefficients are modified in complicated ways by the nonlinear nonlocal term. Nevertheless, these computations can be formulated quite generally in terms of properties of the Fourier transform of the kernel function. When the lengthscale associated with the kernel is longer, our method leads naturally to the derivation of two different, novel, envelope equations that describe aspects of the dynamics in these new regimes. The first of these contains additional bifurcations, and unexpected loops in the bifurcation diagram. The second of these captures the stretched-out nature of the homoclinic snaking curves that arises due to the nonlocal term.Comment: 28 pages, 14 figures. To appear in Physica

Land, Rest & Sacrifice: Ecological Reflections on the Book of Leviticus

The socio-religious regulations of Leviticus offer little-explored perspectives from which to reflect on the relationship between humanity and the non-human creation. The cosmological framework upon which the worldview expressed in Leviticus is constructed places humanity at the fragile interface between creation (order) and chaos (destruction), ever struggling to discern, define and delineate the sacred and the profane. Several texts in Leviticus portray the land as an active character; capable of vomiting, resting and maintaining a ritualistically demanding relationship with God. Not only does the land appear to have a distinct relationship with YHWH, but in fact that relationship predates YHWH’s commitment to Israel. When the people sin, they risk not only the retreat of YHWH’s presence from the sanctuary, but also the land ejecting them in order that it might fulfill its ritual obligations. Each member of the community is responsible for maintaining the well-being of the lived-in world as expressed through obedience to teachings concerning the body, the social group, and cultic behaviour. Within this system, the manifested symbols of created order are those essential elements which enable the sustenance of the whole community: the people, the land, its vegetation and its animals. Responsible human care for this divinely-established ecology is thus ingrained in, and carefully detailed through, the regulations in Leviticus. Important examples include prescriptions for a sabbatical year for the land to rest and to restore its fertility; the Sabbath day as a space of economic disruption and regeneration; agricultural festivals as cultic boundaries of the life of the community; and dietary and cultic laws regulating the killing of animals for humans (as food) or for God (as sacrifice). Disobedience, or sin, renders both the human community, and the land upon which it lives, polluted and unclean. A particularly significant measure of controlling or cleansing the resulting pollution, of both the community and the land, is animal sacrifice – the killing of a perfect animal for God has the potential to restore the delicate balance between chaos and creation. Given these observations, Leviticus' conceptions of the land, animal sacrifice and ritualized rest can be perceived as a fruitful biblical locus of reflection from which to engage contemporary ecological ethics and praxis.AHR

HIV-1 infection of microglial cells in a reconstituted humanized mouse model and identification of compounds that selectively reverse HIV latency.

Most studies of HIV latency focus on the peripheral population of resting memory T cells, but the brain also contains a distinct reservoir of HIV-infected cells in microglia, perivascular macrophages, and astrocytes. Studying HIV in the brain has been challenging, since live cells are difficult to recover from autopsy samples and primate models of SIV infection utilize viruses that are more myeloid-tropic than HIV due to the expression of Vpx. Development of a realistic small animal model would greatly advance studies of this important reservoir and permit definitive studies of HIV latency. When radiation or busulfan-conditioned, immune-deficient NSG mice are transplanted with human hematopoietic stem cells, human cells from the bone marrow enter the brain and differentiate to express microglia-specific markers. After infection with replication competent HIV, virus was detected in these bone marrow-derived human microglia. Studies of HIV latency in this model would be greatly enhanced by the development of compounds that can selectively reverse HIV latency in microglial cells. Our studies have identified members of the CoREST repression complex as key regulators of HIV latency in microglia in both rat and human microglial cell lines. The monoamine oxidase (MAO) and potential CoREST inhibitor, phenelzine, which is brain penetrant, was able to stimulate HIV production in human microglial cell lines and human glial cells recovered from the brains of HIV-infected humanized mice. The humanized mice we have developed therefore show great promise as a model system for the development of strategies aimed at defining and reducing the CNS reservoir

Cohesin cleavage by separase is enhanced by a substrate motif distinct from the cleavage site.

Chromosome segregation begins when the cysteine protease, separase, cleaves the Scc1 subunit of cohesin at the metaphase-to-anaphase transition. Separase is inhibited prior to metaphase by the tightly bound securin protein, which contains a pseudosubstrate motif that blocks the separase active site. To investigate separase substrate specificity and regulation, here we develop a system for producing recombinant, securin-free human separase. Using this enzyme, we identify an LPE motif on the Scc1 substrate that is distinct from the cleavage site and is required for rapid and specific substrate cleavage. Securin also contains a conserved LPE motif, and we provide evidence that this sequence blocks separase engagement of the Scc1 LPE motif. Our results suggest that rapid cohesin cleavage by separase requires a substrate docking interaction outside the active site. This interaction is blocked by securin, providing a second mechanism by which securin inhibits cohesin cleavage

Comparative performance of adult social care research, 1996-2011: a bibliometric assessment

Decision-makers in adult social care are increasingly interested in using evidence from research to support or shape their decisions. The scope and nature of the current landscape of adult social care research (ASCR) needs to be better understood. This paper provides a bibliometric assessment of ASCR outputs from 1996 to 2011. ASCR papers were retrieved using three strategies: from key journals; using keywords and noun phrases; and from additional papers preferentially citing or being cited by other ASCR papers. Overall 195,829 ASCR papers were identified in the bibliographic database Scopus, of which 16% involved at least one author from the UK. The UK output increased 2.45-fold between 1996 and 2011. Among selected countries, those with greater research intensity in ASCR generally had higher citation impact, such as the US, UK, Canada and the Netherlands. The top-5 UK institutions in terms of volume of papers in the UK accounted for 26% of total output. We conclude by noting the limitations to bibliometric analysis of ASCR and examine how such analysis can support the strategic development of the field

A highly specific Escherichia coli qPCR and its comparison with existing methods for environmental waters

The presence of Escherichia coli in environmental waters is considered as evidence of faecal contamination and is therefore commonly used as an indicator in both water quality and food safety analysis. The long period of time between sample collection and obtaining results from existing culture based methods means that contamination events may already impact public health by the time they are detected. The adoption of molecular based methods for E. coli could significantly reduce the time to detection. A new quantitative real-time PCR (qPCR) assay was developed to detect the ybbW gene sequence, which was found to be 100% exclusive and inclusive (specific and sensitive) for E. coli and directly compared for its ability to quantify E. coli in environmental waters against colony counts, quantitative real-time NASBA (qNASBA) targeting clpB and qPCR targeting uidA. Of the 87 E. coli strains tested, 100% were found to be ybbW positive, 94.2% were culture positive, 100% were clpB positive and 98.9% were uidA positive. The qPCR assays had a linear range of quantification over several orders of magnitude, and had high amplification efficiencies when using single isolates as a template. This compared favourably with qNASBA which showed poor linearity and amplification efficiency. When the assays were applied to environmental water samples, qNASBA was unable to reliably quantify E. coli while both qPCR assays were capable of predicting E. coli concentrations in environmental waters. This study highlights the inability of qNASBA targeting mRNA to quantify E. coli in environmental waters, and presents the first E. coli qPCR assay with 100% target exclusivity. The application of a highly exclusive and inclusive qPCR assay has the potential to allow water quality managers to reliably and rapidly detect and quantify E. coli and therefore take appropriate measures to reduce the risk to public health posed by faecal contamination

Flash Sintering, a Novel Technique, for Manufacturing Surrogate and Active Nuclear Materials

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