Regimes of polymer behaviour in drop-on-demand ink-jetting

Three regimes of fast DoD jetting behaviour for solutions of mono-disperse linear polymers have been linked to the underlying polymer molecular chains and their fully extended length L in good solvents. This allows scaling laws in molecular weight to be predicted and applied to experimental jetting results from different DoD print heads. The higher extensional flows encountered in high speed jetting in viscous solvents can fully stretch linear molecules outside the nozzle, permitting jetting of higher polymer content than for purely elastic behaviour. These results are significant for DoD printing at raised jet speeds and will apply to any DoD print head jetting linear polymer solutions.This work was supported by EPSRC grant number RG5560

Ultra-high speed particle image velocimetry on drop-on-demand jetting

Se estudian los conceptos claves de fortuna, virtù y gloria, con elobjeto de buscar algunas aclaraciones sobre el problema de larelación entre moral y política en Maquiavelo. La virtù maquiavelianaincluye, sin duda, múltiples componentes de energía, talento,pero no está completamente exenta de elementos morales. Delconcepto de fortuna podemos extraer una serie de criterios parala acción política que forman parte de la virtù maquiaveliana, lacual, si bien se aleja de la moral cristiana vigente en su tiempo, lesitúa dentro de una moral republicana. Del examen del conceptode gloria descubrimos cómo la gloria es recompensa de la virtù,pero no se reconoce a cualquier político que tiene éxito en susempresas, sino solo a quien salva a la patria y lo hace con mediosbenignos.</jats:p

Oscillations of aqueous PEDOT:PSS fluid droplets and the properties of complex fluids in drop-on-demand inkjet printing

Shear-thinning aqueous poly(3,4-ethylenedioxythiophene): poly(styrene sulphonate) (PEDOT:PSS) fluids were studied under the conditions of drop-on-demand inkjet printing. Ligament retraction caused oscillation of the resulting drops, from which values of surface tension and viscosity were derived. Effective viscosities of <4 mPa s at drop oscillation frequencies of 13–33 kHz were consistent with conventional high-frequency rheometry, with only a small possible contribution from viscoelasticity with a relaxation time of about 6 μs. Strong evidence was found that the viscosity, reduced by shear-thinning in the printhead nozzle, recovered as the drop formed. The low viscosity values measured for the drops in flight were associated with the strong oscillation induced by ligament retraction, while for a weakly perturbed drop the viscosity remained high. Surface tension values in the presence of surfactant were significantly higher than the equilibrium values, and consistent with the surface age of the drops. [Graphical abstract - see article]This work was supported by EPSRC and a consortium of industrial partners (EPSRC Grant no. EP/H018913/1: Innovation in industrial inkjet technology). The high-speed camera and high power flash lamp were provided by the EPSRC Engineering Instrument Pool and we thank Adrian Walker for his help.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.jnnfm.2015.05.00

Analysis of meteorology-chemistry interactions during air pollution episodes using online coupled models within AQMEII Phase-2

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).This study reviews the top ranked meteorology and chemistry interactions in online coupled models recommended by an experts’ survey conducted in COST Action EuMetChem and examines the sensitivity of those interactions during two pollution episodes: the Russian forest fires 25 Jul -15 Aug 2010 and a Saharan dust transport event from 1 Oct -31 Oct 2010 as a part of the AQMEII phase-2 exercise. Three WRF-Chem model simulations were performed for the forest fire case for a baseline without any aerosol feedback on meteorology, a simulation with aerosol direct effects only and a simulation including both direct and indirect effects. For the dust case study, eight WRF-Chem and one WRF-CMAQ simulations were selected from the set of simulations conducted in the framework of AQMEII. Of these two simulations considered no feedbacks, two included direct effects only and five simulations included both direct and indirect effects. The results from both episodes demonstrate that it is important to include the meteorology and chemistry interactions in online-coupled models. Model evaluations using routine observations collected in AQMEII phase-2 and observations from a station in Moscow show that for the fire case the simulation including only aerosol direct effects has better performance than the simulations with no aerosol feedbacks or including both direct and indirect effects. The normalized mean biases are significantly reduced by 10-20% for PM10 when including aerosol direct effects. The analysis for the dust case confirms that models perform better when including aerosol direct effects, but worse when including both aerosol direct and indirect effects, which suggests that the representation of aerosol indirect effects needs to be improved in the model.Peer reviewedFinal Published versio

Mapping replication dynamics in Trypanosoma brucei reveals a link with telomere transcription and antigenic variation

Survival of Trypanosoma brucei depends upon switches in its protective Variant Surface Glycoprotein (VSG) coat by antigenic variation. VSG switching occurs by frequent homologous recombination, which is thought to require locus-specific initiation. Here, we show that a RecQ helicase, RECQ2, acts to repair DNA breaks, including in the telomeric site of VSG expression. Despite this, RECQ2 loss does not impair antigenic variation, but causes increased VSG switching by recombination, arguing against models for VSG switch initiation through direct generation of a DNA double strand break (DSB). Indeed, we show DSBs inefficiently direct recombination in the VSG expression site. By mapping genome replication dynamics, we reveal that the transcribed VSG expression site is the only telomeric site that is early replicating – a differential timing only seen in mammal-infective parasites. Specific association between VSG transcription and replication timing reveals a model for antigenic variation based on replication-derived DNA fragility

Uncovering treatment burden as a key concept for stroke care: a systematic review of qualitative research

&lt;b&gt;Background&lt;/b&gt; Patients with chronic disease may experience complicated management plans requiring significant personal investment. This has been termed ‘treatment burden’ and has been associated with unfavourable outcomes. The aim of this systematic review is to examine the qualitative literature on treatment burden in stroke from the patient perspective.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods and findings&lt;/b&gt; The search strategy centred on: stroke, treatment burden, patient experience, and qualitative methods. We searched: Scopus, CINAHL, Embase, Medline, and PsycINFO. We tracked references, footnotes, and citations. Restrictions included: English language, date of publication January 2000 until February 2013. Two reviewers independently carried out the following: paper screening, data extraction, and data analysis. Data were analysed using framework synthesis, as informed by Normalization Process Theory. Sixty-nine papers were included. Treatment burden includes: (1) making sense of stroke management and planning care, (2) interacting with others, (3) enacting management strategies, and (4) reflecting on management. Health care is fragmented, with poor communication between patient and health care providers. Patients report inadequate information provision. Inpatient care is unsatisfactory, with a perceived lack of empathy from professionals and a shortage of stimulating activities on the ward. Discharge services are poorly coordinated, and accessing health and social care in the community is difficult. The study has potential limitations because it was restricted to studies published in English only and data from low-income countries were scarce.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt; Stroke management is extremely demanding for patients, and treatment burden is influenced by micro and macro organisation of health services. Knowledge deficits mean patients are ill equipped to organise their care and develop coping strategies, making adherence less likely. There is a need to transform the approach to care provision so that services are configured to prioritise patient needs rather than those of health care systems

The aged niche disrupts muscle stem cell quiescence

SUMMARY The niche is a conserved regulator of stem cell quiescence and function. During aging, stem cell function declines. To what extent and by which means age-related changes within the niche contribute to this phenomenon are unknown. We demonstrate that the aged muscle stem cell niche, the muscle fiber, expresses FGF2 under homeostatic conditions, driving a subset of satellite cells to break quiescence and lose self-renewing capacity. We show that relatively dormant aged satellite cells robustly express Sprouty1 (spry1), an inhibitor of FGF signalling. Increasing FGF signalling in aged satellite cells under homeostatic conditions by removing spry1, results in the loss of quiescence, satellite cell depletion and diminished regenerative capacity. Conversely, reducing niche-derived FGF activity through inhibition of FGFR1 signalling or overexpression of spry1 in satellite cells prevents their depletion. These experiments identify an age-dependent change in the stem cell niche that directly influences stem cell quiescence and function

Three-dimensional protonic conductivity in porous organic cage solids

Proton conduction is a fundamental process in biology and in devices such as proton exchange membrane fuel cells. To maximize proton conduction, three-dimensional conduction pathways are preferred over one-dimensional pathways, which prevent conduction in two dimensions. Many crystalline porous solids to date show one-dimensional proton conduction. Here we report porous molecular cages with proton conductivities (up to 10−3 S cm−1 at high relative humidity) that compete with extended metal-organic frameworks. The structure of the organic cage imposes a conduction pathway that is necessarily three-dimensional. The cage molecules also promote proton transfer by confining the water molecules while being sufficiently flexible to allow hydrogen bond reorganization. The proton conduction is explained at the molecular level through a combination of proton conductivity measurements, crystallography, molecular simulations and quasi-elastic neutron scattering. These results provide a starting point for high-temperature, anhydrous proton conductors through inclusion of guests other than water in the cage pores

The sense and nonsense of direct-to-consumer genetic testing for cardiovascular disease

Expectations are high that increasing knowledge of the genetic basis of cardiovascular disease will eventually lead to personalised medicine—to preventive and therapeutic interventions that are targeted to at-risk individuals on the basis of their genetic profiles. Most cardiovascular diseases are caused by a complex interplay of many genetic variants interacting with many non-genetic risk factors such as diet, exercise, smoking and alcohol consumption. Since several years, genetic susceptibility testing for cardiovascular diseases is being offered via the internet directly to consumers. We discuss five reasons why these tests are not useful, namely: (1) the predictive ability is still limited; (2) the risk models used by the companies are based on assumptions that have not been verified; (3) the predicted risks keep changing when new variants are discovered and added to the test; (4) the tests do not consider non-genetic factors in the prediction of cardiovascular disease risk; and (5) the test results will not change recommendations of preventive interventions. Predictive genetic testing for multifactorial forms of cardiovascular disease clearly lacks benefits for the public. Prevention of disease should therefore remain focused on family history and on non-genetic risk factors as diet and physical activity that can have the strongest impact on disease risk, regardless of genetic susceptibility

Development of a framework for genotyping bovine-derived Cryptosporidium parvum, using a multilocus fragment typing tool

Background: There is a need for an integrated genotyping approach for C. parvum; no sufficiently discriminatory scheme to date has been fully validated or widely adopted by veterinary or public health researchers. Multilocus fragment typing (MLFT) can provide good differentiation and is relatively quick and cheap to perform. A MLFT tool was assessed in terms of its typeability, specificity, precision (repeatability and reproducibility), accuracy and ability to genotypically discriminate bovine-derived Cryptosporidium parvum. Methods: With the aim of working towards a consensus, six markers were selected for inclusion based on their successful application in previous studies: MM5, MM18, MM19, TP14, MS1 and MS9. Alleles were assigned according to the fragment sizes of repeat regions amplified, as determined by capillary electrophoresis. In addition, a region of the GP60 gene was amplified and sequenced to determine gp60 subtype and this was added to the allelic profiles of the 6 markers to determine the multilocus genotype (MLG). The MLFT tool was applied to 140 C. parvum samples collected in two cross-sectional studies of UK calves, conducted in Cheshire in 2004 (principally dairy animals) and Aberdeenshire/Caithness in 2011 (beef animals). Results: Typeability was 84 %. The primers did not amplify tested non-parvum species frequently detected in cattle. In terms of repeatability, within- and between-run fragment sizes showed little variability. Between laboratories, fragment sizes differed but allele calling was reproducible. The MLFT had good discriminatory ability (Simpson’s Index of Diversity, SID, was 0.92), compared to gp60 sequencing alone (SID 0.44). Some markers were more informative than others, with MS1 and MS9 proving monoallelic in tested samples. Conclusions: Further inter-laboratory trials are now warranted with the inclusion of human-derived C. parvum samples, allowing progress towards an integrated, standardised typing scheme to enable source attribution and to determine the role of livestock in future outbreaks of human C. parvum