Investigation of the temperature homogeneity of die melt flows in polymer extrusion

Polymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single-point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature

Fluxes of organic contaminants from the river catchment into, through and out of the Humber Estuary, UK

This paper summarises the work done on the distribution and reactivity of organic contaminants (simazine, atrazine, lindane, fluoranthene, pyrene, PCB 77, PCB 118) in the Humber Estuary and associated major rivers, as part of the LOIS programme. The preliminary flux calculations show that the most important contributors of selected organic contaminants were the rivers Trent (45% of simazine, 20% of atrazine), Aire (30% of simazine and 33% of atrazine), Don (36 and 37% of fluoranthene and pyrene) and Ouse (18% of fluoranthene and pyrene). For lindane and PCBs, the Aire and Ouse were the key sources. The water flow in all the rivers shows strong seasonal variations, as do the contaminant concentrations. As a result, the mean daily fluxes of these contaminants displayed a strong seasonality. Annual mean concentrations of simazine and atrazine decreased by more than 50% over the period 1994-1995 in most of the rivers, probably as a result of their restricted use in the UK. Mass balance calculations show that the Humber is a sink for atrazine, lindane, PCB 77 and PCB 118, although the degree of removal is generally much lower for atrazine and lindane than for PCB 77 and PCB 118. Mass balance results also show that the Humber can either be a source of fluoranthene and pyrene (in the suspended particulate phase), or a sink (in the dissolved phase), although overall the Humber acts as sink. The budget exercise represents an attempt to quantify the input and output of selected organic contaminants from catchment to ocean. However, due to limited data and assumptions involved in calculations, the estimates should be considered as an order of magnitude approximation. Further improvement both in resolution and accuracy is required.

Additionality of Incubator Support on Networks of University Spin-Out Firms

The formation rate of university spin-out firms has increased markedly over the past decade. While this is seen as an important channel for the commercialisation of academic research, concerns have centred around high failure rates and no-to-low growth among those which survive compared to other new technology based firms. Universities have responded to this by investing in incubators to assist spin-outs to overcome their liability of newness. Yet how effective are incubators in supporting these firms? Here we examine this in terms of the structural networks that spin-out firms form, the role of the incubator in this and the effect of this on the spin-out process.

Antibiofilm Activity of the Brown Alga Halidrys siliquosa against Clinically Relevant Human Pathogens

The marine brown alga Halidrys siliquosa is known to produce compounds with antifouling activity against several marine bacteria. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of organic extracts obtained from the marine brown alga H. siliquosa against a focused panel of clinically relevant human pathogens commonly associated with biofilm-related infections. The partially fractionated methanolic extract obtained from H. siliquosa collected along the shores of Co. Donegal; Ireland; displayed antimicrobial activity against bacteria of the genus Staphylococcus; Streptococcus; Enterococcus; Pseudomonas; Stenotrophomonas; and Chromobacterium with MIC and MBC values ranging from 0.0391 to 5 mg/mL. Biofilms of S. aureus MRSA were found to be susceptible to the algal methanolic extract with MBEC values ranging from 1.25 mg/mL to 5 mg/mL respectively. Confocal laser scanning microscopy using LIVE/DEAD staining confirmed the antimicrobial nature of the antibiofilm activity observed using the MBEC assay. A bioassay-guided fractionation method was developed yielding 10 active fractions from which to perform purification and structural elucidation of clinically-relevant antibiofilm compounds.

Sorting out mix-ups. The provenance of tissue sections may be confirmed by PCR using microsatellite markers

Standard identification systems usually ensure that biopsy material is correctly associated with a given patient. Sometimes, as when a tumor is unexpectedly found, the provenance (proof of origin) of a tissue sample may be questioned; the tissue may have been mislabelled or contaminated with tissue from another patient. Techniques used to confirm tissue provenance include comparing either tissue markers of gender or ABO blood groups; however, these methods have weak confirmatory power. Recently, the use of DNA-based polymerase chain reaction (PCR) techniques has been reported. Paired, formalin-fixed, paraffin-embedded, 10 microns tissue sections were selected from 17 patients, 8 of whom had carcinoma, either by dividing a biopsy section, using sequential biopsies, or sequential biopsy and autopsy tissue. The resulting 36 samples were coded before analysis. In two additional cases, 1-mm fragments of tumor from one patient were included in the tissue block of benign tissue from another patient, the tumor fragments were identified on hematoxylin-and-eosin-stained sections, separately scraped off the glass slide, and analyzed. Tissue from two clinical cases, one of suspected mislabelling and one with a suspected carry-over of malignant tissue were also investigated. Short tandem repeat sequences (STR) or microsatellites, are 2-5 base pair repeats that vary in their repeat number between individuals. This variation (polymorphism) can be assessed using a PCR. A panel of markers of 3 STRs; ACPP, INT 2, and CYP 19 (on chromosomes 3, 11, and 15, respectively) were used. DNA was isolated from the samples after xylene deparaffinization and proteinase digestion, and was then amplified in a radioactive PCR using primers selected to give a product size ranging from 136-178 bases. Amplified products were electrophoresed on denaturing polyacrylamide gels, dried, and autoradiographed. DNA segments were successfully extracted from all samples but one, which was fixed in Bouin's fluid. By comparing allele sizes from the panel, all tissue pairs (other than the Bouin's pair) were successfully matched, the 1-mm tumor fragments were correctly assigned, and the two clinical problems were solved. STRs are highly informative and robust markers, well suited to PCR of small portions of tissue sections, and are an effective method to confirm the provenance of benign and malignant biopsy and autopsy material.

Speaking Out Online:The Benefits and Risks of Speaking About Sexual Violence for Young People

Speaking out about sexual violence has been a fundamental part of feminist politics since the 1970s. The practice of narrating experiences of violence, either publicly or to friends and family aims to combat the culture of silence and stigmatisation that surrounds sexual violence while also helping individuals to gain a sense of empowerment and connect with other survivors. However, speaking out also contains inherent risks, especially for young people. Survivors may meet with stigmatising or disbelieving responses, and they may lose control over who knows their story and the way in which it is told and retold.
These risks and benefits are altered, and potentially exacerbated, in an online environment. While social media may increase survivors’ ability to contact and connect with others with similar experiences it also makes it harder to control when and how their story is shared. The disjuncture between online and offline environments may also increase feelings of stigmatisation and isolation.
There is a need to explore the specific risks and benefits of speaking out online given both young people’s extensive use of social media for social interactions and the increasing tendency for support and educational services targeted at young people to make use of social media and online environments. This paper draws on literature and some preliminary research to consider both risks and benefits of speaking out online and to open a conversation about the creation of supportive spaces and mechanisms for young people to speak about sexual violence in online environments.

Establishing the validity of English GP Patient Survey items evaluating out-of-hours care

Background A 2014 national audit used the English General Practice Patient Survey (GPPS) to compare service users’ experience of out-of-hours general practitioner (GP) services, yet there is no published evidence on the validity of these GPPS items. Objectives Establish the construct and concurrent validity of GPPS items evaluating service users’ experience of GP out-of-hours care. Methods Cross-sectional postal survey of service users (n=1396) of six English out-of-hours providers. Participants reported on four GPPS items evaluating out-of-hours care (three items modified following cognitive interviews with service users), and 14 evaluative items from the Out-of-hours Patient Questionnaire (OPQ). Construct validity was assessed through correlations between any reliable (Cochran's α>0.7) scales, as suggested by a principal component analysis of the modified GPPS items, with the ‘entry access’ (four items) and ‘consultation satisfaction’ (10 items) OPQ subscales. Concurrent validity was determined by investigating whether each modified GPPS item was associated with thematically related items from the OPQ using linear regressions. Results The modified GPPS item-set formed a single scale (α=0.77), which summarised the two-component structure of the OPQ moderately well; explaining 39.7% of variation in the ‘entry access’ scores (r=0.63) and 44.0% of variation in the ‘consultation satisfaction’ scores (r=0.66), demonstrating acceptable construct validity. Concurrent validity was verified as each modified GPPS item was highly associated with a distinct set of related items from the OPQ. Conclusions Minor modifications are required for the English GPPS items evaluating out-of-hours care to improve comprehension by service users. A modified question set was demonstrated to comprise a valid measure of service users’ overall satisfaction with out-of-hours care received. This demonstrates the potential for the use of as few as four items in benchmarking providers and assisting services in identifying, implementing and assessing quality improvement initiatives.

The use of patient experience survey data by out-of-hours primary care services: a qualitative interview study

Background English National Quality Requirements mandate out-of-hours primary care services to routinely audit patient experience, but do not state how it should be done.

Objectives We explored how providers collect patient feedback data and use it to inform service provision. We also explored staff views on the utility of out-of-hours questions from the English General Practice Patient Survey (GPPS).

Methods A qualitative study was conducted with 31 staff (comprising service managers, general practitioners and administrators) from 11 out-of-hours primary care providers in England, UK. Staff responsible for patient experience audits within their service were sampled and data collected via face-to-face semistructured interviews.

Results Although most providers regularly audited their patients’ experiences by using patient surveys, many participants expressed a strong preference for additional qualitative feedback. Staff provided examples of small changes to service delivery resulting from patient feedback, but service-wide changes were not instigated. Perceptions that patients lacked sufficient understanding of the urgent care system in which out-of-hours primary care services operate were common and a barrier to using feedback to enable change. Participants recognised the value of using patient experience feedback to benchmark services, but perceived weaknesses in the out-of-hours items from the GPPS led them to question the validity of using these data for benchmarking in its current form.

Conclusions The lack of clarity around how out-of-hours providers should audit patient experience hinders the utility of the National Quality Requirements. Although surveys were common, patient feedback data had only a limited role in service change. Data derived from the GPPS may be used to benchmark service providers, but refinement of the out-of-hours items is needed.

Butt out - baby on board

It is estimated that the cost of treating women and their infants with smoking related problems is up to £87.5 million each year (ASH, 2013). Whilst these statistics depict a major problem for the National Health Service, they challenge midwives to become change agents within this health promotion area. A desired outcome from The Maternity Strategy for Northern Ireland (DHSSPSNI, 2012) includes giving every baby and family the best start in life. Assisting women to stop smoking before conception, could help to achieve this outcome and provide opportunities for a greater start in life following birth.

Solid-liquid interfacial free energy out of equilibrium

The properties of the interface between solid and melt are key to solidification and melting, as the interfacial free energy introduces a kinetic barrier to phase transitions. This makes solidification happen below the melting temperature, in out-of-equilibrium conditions at which the interfacial free energy is ill defined. Here we draw a connection between the atomistic description of a diffuse solid-liquid interface and its thermodynamic characterization. This framework resolves the ambiguities in defining the solid-liquid interfacial free energy above and below the melting temperature. In addition, we introduce a simulation protocol that allows solid-liquid interfaces to be reversibly created and destroyed at conditions relevant for experiments. We directly evaluate the value of the interfacial free energy away from the melting point for a simple but realistic atomic potential, and find a more complex temperature dependence than the constant positive slope that has been generally assumed based on phenomenological considerations and that has been used to interpret experiments. This methodology could be easily extended to the study of other phase transitions, from condensation to precipitation. Our analysis can help reconcile the textbook picture of classical nucleation theory with the growing body of atomistic studies and mesoscale models of solidification.

Moving Out of Conflict: Negotiating Social Identity in Response to Segregation in Northern Ireland

This paper examines the impact of territoriality on young people’s everyday experiences in Northern Ireland’s segregated communities. It shows how urban encounters are reproduced through negotiating differences and the ways in which living in divided communities escalates moods of social inequality and spatial imbalances. The empirical study undertaken in the city of Derry shows how individuals and community groups position and identify themselves under the impact of social segregation. Building on Gordon Allport’s (1954) theories of contact, I explain how people in Derry have established their own sense of belonging, of who they are, based on their group memberships which eventually became an important source of pride and selfesteem. They also presented their own intertextual references as a cause of routine survival and belonging, allowing them to be more constructive about their future. Under deeply rooted segregation in Northern Ireland, the young generations are sought to provide lasting change to foster peace and integration between the two communities.

Impact of fractionation on out-of-field survival and DNA damage responses following exposure to intensity modulated radiation fields

To limit toxicity to normal tissues adjacent to the target tumour volume, radiotherapy is delivered using fractionated regimes whereby the total prescribed dose is given as a series of sequential smaller doses separated by specific time intervals. The impact of fractionation on out-of-field survival and DNA damage responses was determined in AGO-1522 primary human fibroblasts and MCF-7 breast tumour cells using uniform and modulated exposures delivered using a 225 kVp x-ray source. Responses to fractionated schedules (two equal fractions delivered with time intervals from 4 h to 48 h) were compared to those following acute exposures. Cell survival and DNA damage repair measurements indicate that cellular responses to fractionated non-uniform exposures differ from those seen in uniform exposures for the investigated cell lines. Specifically, there is a consistent lack of repair observed in the out-of-field populations during intervals between fractions, confirming the importance of cell signalling to out-of-field responses in a fractionated radiation schedule, and this needs to be confirmed for a wider range of cell lines and conditions.

YSOVAR: Mid-infrared Variability in NGC 1333

As part of the Young Stellar Object VARiability (YSOVAR) program, wemonitored NGC 1333 for ∼35 days at 3.6 and 4.5 μm using theSpitzer Space Telescope. We report here on the mid-infrared variabilityof the point sources in the ∼10‧ × ∼20‧ areacentered on 03:29:06, +31:19:30 (J2000). Out of 701 light curves ineither channel, we find 78 variables over the YSOVAR campaign. Abouthalf of the members are variable. The variable fraction for the mostembedded spectral energy distributions (SEDs) (Class I, flat) is higherthan that for less embedded SEDs (Class II), which is in turn higherthan the star-like SEDs (Class III). A few objects have amplitudes(10–90th percentile brightness) in [3.6] or [4.5] > 0.2 mag; amore typical amplitude is 0.1–0.15 mag. The largest color changeis >0.2 mag. There are 24 periodic objects, with 40% of them beingflat SED class. This may mean that the periodic signal is primarily fromthe disk, not the photosphere, in those cases. We find 9 variableslikely to be “dippers,” where texture in the disk occultsthe central star, and 11 likely to be “bursters,” whereaccretion instabilities create brightness bursts. There are 39 objectsthat have significant trends in [3.6]–[4.5] color over thecampaign, about evenly divided between redder-when-fainter (consistentwith extinction variations) and bluer-when-fainter. About a third of the17 Class 0 and/or jet-driving sources from the literature are variableover the YSOVAR campaign, and a larger fraction (∼half) are variablebetween the YSOVAR campaign and the cryogenic-era Spitzer observations(6–7 years), perhaps because it takes time for the envelope torespond to changes in the central source. The NGC 1333 brown dwarfs donot stand out from the stellar light curves in any way except there is amuch larger fraction of periodic objects (∼60% of variable browndwarfs are periodic, compared to ∼30% of the variables overall).