Suspension and levitation in nonlinear theories

I investigate stable equilibria of bodies in potential fields satisfying a generalized Poisson equation: divergence[m(grad phi) grad phi]= source density. This describes diverse systems such as nonlinear dielectrics, certain flow problems, magnets, and superconductors in nonlinear magnetic media; equilibria of forced soap films; and equilibria in certain nonlinear field theories such as Born-Infeld electromagnetism. Earnshaw's theorem, totally barring stable equilibria in the linear case, breaks down. While it is still impossible to suspend a test, point charge or dipole, one can suspend point bodies of finite charge, or extended test-charge bodies. I examine circumstances under which this can be done, using limits and special cases. I also consider the analogue of magnetic trapping of neutral (dipolar) particles.Comment: Five pages, Revtex, to appear in Physics Letters

Developing theory in motivational interviewing: academic and practitioner perspectives from MICBT integration

Motivational Interviewing (MI) and Cognitive Behaviour Therapy (CBT) are both evidence based psychosocial interventions. Motivational interviewing has not sought to develop its own comprehensive theory (Miller & Rollnick, 2012) although it has developed hypotheses on why MI works. This project has looks at what an integration of these two approaches can tell us about motivational interviewing’s theory, hypothesised mechanisms of action and efficacy. It has set out to examine and explore existing theory through qualitative research. This included Semi structured interviews with researchers and practitioners who are experts in the integration of MI and CBT (MICBT). Their views and existing literature were used develop understanding about MI efficacy. A critical realist philosophical framework and Theoretical Thematic analysis was used to explore and test MI theory. A number of themes around hypothesised mechanisms and MI theory emerged from both sets of participants. These included psychological safety, alliance, responding to resistance, acceptance, compassion and positive emotion. A relational rather than a technical practice was emphasised and the theory relating to that observed. Theory around Power, its negative and positive operation in people’s lives arose frequently; as did hypothesised mechanisms relating to power differentials and MI as a ‘power yielding’ approach. Building on insights from evolutionary theory, links were made to a more detailed consideration of the effects of social context on research, practice and the ability of individuals to make change. This project challenges a narrow-individualised approach to research and intervention, emphasising the need to take into account the effects of social inequality and individual social circumstances. The project has illustrated some of the reality of translating theory into real-world practice and suggests expanding MI theory so that it is more contextualised. The centrality of understanding power and power structures may be a useful addition to an understanding of why MI works. An increased awareness of social context and its impacts raise questions about how individual and societal level interventions could work together to improve health behaviour change. Finally, a number of suggestions for future research are made, including that individualised interventions need to be evaluated in real-world services, with direct consultation of and involvement of service users

Comparing measured and modelled PFOS concentrations in a UK freshwater catchment and estimating emission rates

The lifecycle, sources and fate of perfluorooctane sulfonate (PFOS) continue to generate scientific and political interest, particularly since PFOS was listed by the Stockholm Convention and largely restricted in Europe. It continues to be detected in aquatic environments, with only limited studies into the on-going sources. This paper explores PFOS emissions discharged by the general population into a small catchment comprising two rivers in the UK. A sampling campaign was undertaken to improve our understanding of population-derived PFOS sources from sewage treatment plants (STPs) and in rivers. A corresponding modelling exercise allowed an emission estimate of 13 μg/day/per capita to be derived for the Aire and Calder rivers. PFOS emission was linked to STP discharges bylinear regression of measured and modelled concntrations (R2 = 0.49–0.85). The model was able to accurately estimate the spatial trends of PFOS in the rivers, while predicted concentrations were within a factor of three based on per capita emission values taken from the literature. Measured PFOS concentrations in rivers suggested that emissions from STPs are partially dependent on treatment type, where plants with secondary or tertiary treatment such as activated sludge processes emit less PFOS, possibly due to increased partitioning and retention. With refinements based on the type of treatment at each STP, predictions were further improved. The total PFOS mass discharged annually via rivers from the UK has been estimated to be between 215 and 310 kg, based on the per capita emission range derived in this study

Forces During Bacteriophage DNA Packaging and Ejection

The conjunction of insights from structural biology, solution biochemistry, genetics and single molecule biophysics has provided a renewed impetus for the construction of quantitative models of biological processes. One area that has been a beneficiary of these experimental techniques is the study of viruses. In this paper we describe how the insights obtained from such experiments can be utilized to construct physical models of processes in the viral life cycle. We focus on dsDNA bacteriophages and show that the bending elasticity of DNA and its electrostatics in solution can be combined to determine the forces experienced during packaging and ejection of the viral genome. Furthermore, we quantitatively analyze the effect of fluid viscosity and capsid expansion on the forces experienced during packaging. Finally, we present a model for DNA ejection from bacteriophages based on the hypothesis that the energy stored in the tightly packed genome within the capsid leads to its forceful ejection. The predictions of our model can be tested through experiments in vitro where DNA ejection is inhibited by the application of external osmotic pressure

Protocol for an independent patient data meta-analysis of prophylactic mesh placement for incisional hernia prevention after abdominal aortic aneurysm surgery:a collaborative European Hernia Society project (I-PREVENT-AAA)

Introduction Incisional hernia (IH) is a prevalent and potentially dangerous complication of abdominal surgery, especially in high-risk groups. Mesh reinforcement of the abdominal wall has been studied as a potential intervention to prevent IHs. Randomised controlled trials (RCTs) have demonstrated that prophylactic mesh reinforcement after abdominal surgery, in general, is effective and safe. In patients with abdominal aortic aneurysm (AAA), prophylactic mesh reinforcement after open repair has not yet been recommended in official guidelines, because of relatively small sample sizes in individual trials. Furthermore, the identification of subgroups that benefit most from prophylactic mesh placement requires larger patient numbers. Our primary aim is to evaluate the efficacy and effectiveness of the use of a prophylactic mesh after open AAA surgery to prevent IH by performing an individual patient data meta-analysis (IPDMA). Secondary aims include the evaluation of postoperative complications, pain and quality of life, and the identification of potential subgroups that benefit most from prophylactic mesh reinforcement. Methods and analysis We will conduct a systematic review to identify RCTs that study prophylactic mesh placement after open AAA surgery. Cochrane Central Register of Controlled Trials, MEDLINE Ovid, Embase, Web of Science Core Collection and Google Scholar will be searched from the date of inception onwards. RCTs must directly compare primary sutured closure with mesh closure in adult patients who undergo open AAA surgery. Lead authors of eligible studies will be asked to share individual participant data (IPD). The risk of bias (ROB) for each included study will be assessed using the Cochrane ROB tool. An IPDMA will be performed to evaluate the efficacy, with the IH rate as the primary outcome.</p

Protocol for an independent patient data meta-analysis of prophylactic mesh placement for incisional hernia prevention after abdominal aortic aneurysm surgery:a collaborative European Hernia Society project (I-PREVENT-AAA)

Introduction Incisional hernia (IH) is a prevalent and potentially dangerous complication of abdominal surgery, especially in high-risk groups. Mesh reinforcement of the abdominal wall has been studied as a potential intervention to prevent IHs. Randomised controlled trials (RCTs) have demonstrated that prophylactic mesh reinforcement after abdominal surgery, in general, is effective and safe. In patients with abdominal aortic aneurysm (AAA), prophylactic mesh reinforcement after open repair has not yet been recommended in official guidelines, because of relatively small sample sizes in individual trials. Furthermore, the identification of subgroups that benefit most from prophylactic mesh placement requires larger patient numbers. Our primary aim is to evaluate the efficacy and effectiveness of the use of a prophylactic mesh after open AAA surgery to prevent IH by performing an individual patient data meta-analysis (IPDMA). Secondary aims include the evaluation of postoperative complications, pain and quality of life, and the identification of potential subgroups that benefit most from prophylactic mesh reinforcement. Methods and analysis We will conduct a systematic review to identify RCTs that study prophylactic mesh placement after open AAA surgery. Cochrane Central Register of Controlled Trials, MEDLINE Ovid, Embase, Web of Science Core Collection and Google Scholar will be searched from the date of inception onwards. RCTs must directly compare primary sutured closure with mesh closure in adult patients who undergo open AAA surgery. Lead authors of eligible studies will be asked to share individual participant data (IPD). The risk of bias (ROB) for each included study will be assessed using the Cochrane ROB tool. An IPDMA will be performed to evaluate the efficacy, with the IH rate as the primary outcome.</p

10Gb/s low-cost directly modulated multi-electrode laser with suppressed thermal wavelength drift for burst-mode upstream transmission in TWDM-PONs

We report on a novel 10Gb/s low-cost multi-electrode DML employed as a very wavelength stable burst-mode source for upstream TWDM-PONs. 10X wavelength drift reduction is achieved compared to conventional DMLs enabling transmission on 100GHz grid

Active centromere and chromosome identification in fixed cell lines

BACKGROUND: The centromere plays a crucial role in ensuring the fidelity of chromosome segregation during cell divisions. However, in cancer and constitutional disorders, the presence of more than one active centromere on a chromosome may be a contributing factor to chromosome instability and could also have predictive value in disease progression, making the detection of properly functioning centromeres important. Thus far, antibodies that are widely used for functional centromere detection mainly work on freshly harvested cells whereas most cytogenetic samples are stored long-term in methanol-acetic acid fixative. Hence, we aimed to identify antibodies that would recognise active centromere antigens on methanol-acetic acid fixed cells. RESULTS: A panel of active centromere protein antibodies was tested and we found that a rabbit monoclonal antibody against human CENP-C recognises the active centromeres of cells fixed in methanol-acetic acid. We then tested and compared combinations of established methods namely centromere fluorescence in situ hybridisation (cenFISH), centromere protein immunofluorescence (CENP-IF) and multicolour FISH (mFISH), and showed the usefulness of CENP-IF together with cenFISH followed by mFISH (CENP-IF-cenFISH-mFISH) with the aforementioned anti-CENP-C antibody. We further demonstrated the utility of our method in two cancer cell lines with high proportion of centromere defects namely neocentromere and functional dicentric. CONCLUSIONS: We propose the incorporation of the CENP-IF-cenFISH-mFISH method using a commercially available rabbit monoclonal anti-CENP-C into established methods such as dicentric chromosome assay (DCA), prenatal karyotype screening in addition to constitutional and cancer karyotyping. This method will provide a more accurate assessment of centromere abnormality status in chromosome instability disorders

Inspiring STEM undergraduates to tackle the AMR crisis

To address the growing problem of antimicrobial resistance (AMR), it is necessary to invest in, inspire and attract future generations of scientists to this research area. Undergraduate education should be a focus for attention and efforts should be made to ensure that students are afforded opportunities to actively engage with AMR. We illustrate how as a topic AMR provides opportunities to deliver effective research-led teaching in addition to traditional teaching methods. We have used a selection of case studies to illustrate how students can be engaged with AMR using a variety of research-led approaches to develop the required skills for biology-centric students. In addition, we indicate how these skills map to the UK Quality Assurance Framework and the Vision and Change report developed by the American Association for the Advancement of Science