Current-Induced Magnetization Reversal in High Magnetic Fields in Co/Cu/Co Nanopillars

Current-induced magnetization dynamics in Co/Cu/Co trilayer nanopillars (~100nm in diameter) has been studied experimentally for large applied fields perpendicular to the layers. An abrupt and hysteretic increase in dynamic resistance is observed at high current densities for one polarity of the current, comparable to the giant magnetoresistance effect observed at low fields. A micromagnetic model, that includes a spin-transfer torque, suggests that the current induces a complete reversal of the thin Co layer to alignment antiparallel to the applied field-that is, to a state of maximum magnetic energy.Comment: 11 pages, 3 figures, (submitted to Phys. Rev. Lett.), added missing figure caption of fig. 3, updated to published versio

Structural and wetting properties of nature\u27s finest silks (order Embioptera)

Insects from the order Embioptera (webspinners) spin silk fibres which are less than 200 nm in diameter. In this work, we characterized and compared the diameters of single silk fibres from nine species—Antipaluria urichi, Pararhagadochir trinitatis, Saussurembia calypso, Diradius vandykei, Aposthonia ceylonica, Haploembia solieri, H. tarsalis, Oligotoma nigra and O. saundersii. Silk from seven of these species have not been previously quantified. Our studies cover five of the 10 named taxonomic families and represent about one third of the known taxonomic family-level diversity in the order Embioptera. Naturally spun silk varied in diameter from 43.6 ± 1.7 nm for D. vandykei to 122.4 ± 3.2 nm for An. urichi. Mean fibre diameter did not correlate with adult female body length. Fibre diameter is more similar in closely related species than in more distantly related species. Field observations indicated that silk appears shiny and smooth when exposed to rainwater. We therefore measured contact angles to learn more about interactions between silk and water. Higher contact angles were measured for silks with wider fibre diameter and higher quantity of hydrophobic amino acids. High static contact angles (ranging up to 122° ± 3° for An. urichi) indicated that silken sheets spun by four arboreal, webspinner species were hydrophobic. A second contact angle measurement made on a previously wetted patch of silk resulted in a lower contact angle (average difference was greater than 27°) for all four species. Our studies suggest that silk fibres which had been previously exposed to water exhibited irreversible changes in hydrophobicity and water adhesion properties. Our results are in alignment with the ‘super-pinning’ site hypothesis by Yarger and co-workers to describe the hydrophobic, yet water adhesive, properties exhibited by webspinner silk fibres. The physical and chemical insights gained here may inform the synthesis and development of smaller diameter silk fibres with unique water adhesion properties

Spatial distribution of local currents of massless Dirac fermions in quantum transport through graphene nanoribbons

We employ the formalism of bond currents, expressed in terms of the nonequilibrium Green functions, to image the charge flow between two sites of the honeycomb lattice of graphene ribbons of few nanometers width. In sharp contrast to nonrelativistic electrons, current density profiles of quantum transport at energies close to the Dirac point in clean zigzag graphene nanoribbons (ZGNR) differs markedly from the profiles of charge density peaked at the edges due to zero-energy localized edge states. For transport through the lowest propagating mode induced by these edge states, edge vacancies do not affect current density peaked in the center of ZGNR. The long-range potential of a single impurity acts to reduce local current around it while concurrently increasing the current density along the zigzag edge, so that ZGNR conductance remains perfect $G=2e^2/h$.Comment: 5 pages, 5 figure

Shapes, contact angles, and line tensions of droplets on cylinders

Using an interface displacement model we calculate the shapes of nanometer-size liquid droplets on homogeneous cylindrical surfaces. We determine effective contact angles and line tensions, the latter defined as excess free energies per unit length associated with the two contact lines at the ends of the droplet. The dependences of these quantities on the cylinder radius and on the volume of the droplets are analyzed.Comment: 26 pages, RevTeX, 10 Figure

Modulation of Polar Lipid Profiles in Chlorella sp. in Response to Nutrient Limitation

We evaluate the effects of nutrient limitation on cellular composition of polar lipid classes/species in Chlorella sp. using modern polar lipidomic profiling methods (Liquid Chromatography-Tandem Mass Spectrometry; LC-MS/MS). Total polar lipid concentration was highest in nutrient-replete (HN) cultures with a significant reduction in monogalactosyldiacylglycerol (MGDG), phosphatidylglycerol (PG), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) class concentrations for nutrient-deplete (LN) cultures. Moreover, reductions in the abundance of MGDG relative to total polar lipids versus an increase in the relative abundance of digalactosyldiacylglycerol (DGDG) were recorded in LN cultures. In HN cultures, polar lipid species composition remained relatively constant throughout culture with high degrees of unsaturation associated with acyl moieties. Conversely, in LN cultures lipid species composition shifted towards greater saturation of acyl moieties. Multivariate analyses revealed that changes in the abundance of a number of species contributed to the dissimilarity between LN and HN cultures but with dominant effects from certain species e.g. reduction in MGDG 34:7 (18:3/16:4). Results demonstrate that Chlorella sp. significantly alters its polar lipidome in response to nutrient limitation and this is discussed in terms of physiological significance and polar lipids production for applied microalgal production systems

Draft genome sequence of the coccolithovirus EhV-84

The Coccolithoviridae is a recently discovered group of viruses that infect the marine coccolithophorid Emiliania huxleyi. Emiliania huxleyi virus 84 (EhV-84) has a 160 -180 nm diameter icosahedral structure and a genome of approximately 400 kbp. Here we describe the structural and genomic features of this virus, together with a near complete draft genome sequence (~99%) and its annotation. This is the fourth genome sequence of a member of the coccolithovirus family

Community Occupational Therapy in Dementia intervention for people with mild to moderate dementia and their family carers in the UK: the VALID research programme including RCT

BACKGROUND: People with dementia find it increasingly difficult to carry out daily activities (activities of daily living), and may require increasing support from family carers. Researchers in the Netherlands developed the Community Occupational Therapy in Dementia intervention, which was delivered in 10 1-hour sessions over 5 weeks to people with dementia and their family carers at home. Community Occupational Therapy in Dementia was found to be clinically effective and cost-effective. OBJECTIVES: Translate and adapt Community Occupational Therapy in Dementia to develop the Community Occupational Therapy in Dementia - the UK version intervention and training programme and to optimise its suitability for use within the UK. To estimate the clinical effectiveness and cost-effectiveness of Community Occupational Therapy in Dementia - the UK version for people with mild to moderate dementia and their family carers compared with treatment as usual. DESIGN: The development phase used mixed methods to develop Community Occupational Therapy in Dementia - the UK version: translation, expert review, and adaptation of the manual and training materials; training occupational therapists; focus groups and interviews, including occupational therapists, managers, people with dementia and family carers; consensus conference; and an online survey of occupational therapists to scope UK practice. A multicentre, two-arm, parallel-group, single-blind individually randomised pragmatic trial was preceded by an internal pilot. Pairs were randomly allocated between Community Occupational Therapy in Dementia - the UK version and treatment as usual. A cost–utility analysis, fidelity study and qualitative study were also completed. SETTING: Community services for people with dementia across England. PARTICIPANTS: People with mild to moderate dementia recruited in pairs with a family carer/supporter. INTERVENTIONS: Community Occupational Therapy in Dementia - the UK version is an activity-based, goal-setting approach for people with dementia and family carers, and is delivered at home by an occupational therapist for 10 hours over 10 weeks. Treatment as usual comprised the usual local service provision, which may or may not include standard occupational therapy. MAIN OUTCOMES MEASURES: Data were collected through interviews conducted in person with dyads at baseline and at 12 and 26 weeks post randomisation, and then over the telephone with a reduced sample of just carers at 52 and 78 weeks post randomisation. The primary outcome was the Bristol Activities of Daily Living Scale at 26 weeks. The secondary outcomes were as follows: person with dementia – cognition, activities of daily living, quality of life and mood; carer – sense of competence, quality of life and mood; all participants – social contacts, leisure activities and serious adverse events. RESULTS: The Community Occupational Therapy in Dementia manual and training materials were translated and reviewed. In total, 44 occupational therapists were trained and delivered Community Occupational Therapy in Dementia to 130 pairs. A total of 197 occupational therapists completed the survey, of whom 138 also provided qualitative data. In total, 31 people attended the consensus conference. Community Occupational Therapy in Dementia - the UK version has more flexibility than Community Occupational Therapy in Dementia in terms of content and delivery; for example, occupational therapists can use the wider range of assessment tools that are already in regular use within UK practice and the time span for delivery is 10 weeks to better meet the needs of pairs and be more feasible for services to deliver. In total, 31 occupational therapists provided Community Occupational Therapy in Dementia - the UK version within the randomised controlled trial. A total of 468 pairs were randomised (249 pairs to Community Occupational Therapy in Dementia - the UK version, 219 pairs to treatment as usual). People with dementia ranged in age from 55 to 97 years (mean 78.6 years), and family carers ranged in age from 29 to 94 years (mean 69.1 years). The majority of those with dementia (74.8%) were married; 19.2% lived alone. Most family carers (72.6%) were spouses but 22.2% were adult children. At 26 weeks, 406 (87%) pairs remained in the trial, and the Bristol Activities of Daily Living Scale total score did not differ at the 5% level when comparing groups (adjusted mean difference estimate 0.35, 95% confidence interval –0.81 to 1.51; p = 0.55). The adjusted (for baseline Bristol Activities of Daily Living Scale total score and randomised group) intracluster correlation coefficient estimate at week 26 was 0.043. There were no significant differences in secondary outcomes. At 52 and 78 weeks, there were no differences between the two groups in Bristol Activities of Daily Living Scale total score and secondary outcomes. The probability that Community Occupational Therapy in Dementia - the UK version is cost-effective at a threshold of willingness to pay per quality-adjusted life-year of £20,000 is 0.02%. In the qualitative interviews, participants reported positive benefits and outcomes. Of the 249 pairs allocated to Community Occupational Therapy in Dementia - the UK version, 227 reached the goal-setting phase, and 838 of the 920 goals set (90.8%) were fully or partially achieved. LIMITATIONS: The development phase took longer than estimated because of translation time and organisational delays in delivering the intervention. Recruitment to the randomised controlled trial took longer than expected. Fidelity overall was moderate, with variation across sites and therapists. It is possible that Community Occupational Therapy in Dementia - the UK version did not work well in the UK service model in which usual care differs from that in the Netherlands. CONCLUSIONS: This programme used a rigorous process to develop Community Occupational Therapy in Dementia - the UK version but found no statistical evidence of clinical effectiveness or cost-effectiveness compared with usual care. Qualitative findings provided positive examples of how Community Occupational Therapy in Dementia - the UK version had enabled people to live well with dementia. FUTURE WORK: Developing tools to measure more meaningful outcomes, such as goals achieved or the quantity and quality of activity participation, with less reliance on proxy data, to collect the views and experiences of people with dementia themselves. TRIAL REGISTRATION: This trial was registered as ISRCTN10748953 (WP3 and WP4). FUNDING: This project was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 11, No. 5. See the NIHR Journals Library website for further project information

Harmful Algal Blooms and their impacts on shellfish mariculture follow regionally distinct patterns of water circulation in the western English Channel during the 2018 heatwave

Harmful algal blooms (HABs) can have severe ecological, societal and economic impacts upon marine ecosystems, human health and the seafood industry. We evaluated changes in marine plankton communities with prevailing physico-chemical conditions throughout an exceptionally warm summer (2018), to elucidate key factors governing HABs and their impacts on shellfish mariculture in the western English Channel. Despite warm, stable weather conditions and widespread seasonal stratification throughout the summer, divergent plankton community compositions were observed at two rope-grown mussel (Mytilus edulis) farms (St Austell Bay and Lyme Bay) and a long-term ecological research LTER site (Plymouth L4). There were significant differences between sites in the abundances of HAB species, including Dinophysis spp. and Karenia mikimotoi, whose cell counts bloomed in excess of UK Food Standards Agency (FSA) advisory ‘trigger’ levels at Plymouth L4 and St Austell Bay, but not at the Lyme Bay site. The K. mikimotoi bloom occurred over two weeks in August and comprised up to 88% of the standing phytoplankton biomass in St Austell Bay. Dinophysis spp. also bloomed here from May to September, constituting up to 28% of phytoplankton biomass. This protracted bloom resulted in concentrations of Dinophysis toxins 1 & 2 and pectenotoxins and okadaic acid in shellfish, which closed shellfish harvesting operations on farms located in St Austell Bay, and other shellfish sites in the west of the western English Channel (but not in the east of the region). Inter-site differences in the abundances of these and other HAB species were associated with variations in water circulation and co-occurring phytoplankton and zooplankton communities. Furthermore, plankton monitoring data obtained from the L4 site over the past 3 decades showed HAB species (including Dinophysis spp.) with abundances commonly occurring above advisory trigger levels during warmer periods, such as that coinciding with our study. Under projected climate warming these blooms are likely to continue to be governed by regionally distinct patterns of water circulation, which need to be taken into account in marine spatial planning, when assessing the suitability of new shellfish mariculture site