1,535 research outputs found
Growth-induced mass flows in fungal networks
Cord-forming fungi form extensive networks that continuously adapt to
maintain an efficient transport system. As osmotically driven water uptake is
often distal from the tips, and aqueous fluids are incompressible, we propose
that growth induces mass flows across the mycelium, whether or not there are
intrahyphal concentration gradients. We imaged the temporal evolution of
networks formed by Phanerochaete velutina, and at each stage calculated the
unique set of currents that account for the observed changes in cord volume,
while minimising the work required to overcome viscous drag. Predicted speeds
were in reasonable agreement with experimental data, and the pressure gradients
needed to produce these flows are small. Furthermore, cords that were predicted
to carry fast-moving or large currents were significantly more likely to
increase in size than cords with slow-moving or small currents. The
incompressibility of the fluids within fungi means there is a rapid global
response to local fluid movements. Hence velocity of fluid flow is a local
signal that conveys quasi-global information about the role of a cord within
the mycelium. We suggest that fluid incompressibility and the coupling of
growth and mass flow are critical physical features that enable the development
of efficient, adaptive, biological transport networks.Comment: To be published in PRSB. 20 pages, plus 8 pages of supplementary
information, and 3 page bibliograph
The alpha-effect in cyclic secondary amines: new scaffolds for iminium ion accelerated transformations
Five-membered secondary amine heterocycles containing an α-heteroatom were prepared and shown to be ineffective as catalysts for the iminium ion catalysed Diels–Alder reaction between cinnamaldehyde and cyclopentadiene. Their six-membered counterparts proved to be highly active catalysts. In stark contrast, the catalytic activity observed when comparing the non α-heteroatom cyclic amines proline methyl ester and methyl pipecolinate showed the five-membered ring amine was significantly more active. Concurrent density functional theoretical calculations suggest a rationale for the observed trends in reactivity, highlighting that LUMO activation through an iminium ion intermediate plays a key role in catalytic activity
How do I sound to me? Perceived changes in communication in Parkinson's disease
Objective: To examine self and carer perceived changes in communication associated with Parkinson's disease and relate these to speech intelligibility, gender, age and other disease measures.
Design: Cross-sectional survey of a hospital- and community-based sample of 176 people with Parkinson's disease and their carers using a questionnaire based on semantic differential techniques.
Participants: One hundred and four people with Parkinson's disease with no history of communication difficulties prior to onset of their Parkinson's disease and 45 primary carers who returned completed questionnaires.
Main outcome measures: Differences in ratings for `before' the onset of Parkinson's disease versus present status.
Results: There was a strong perception of negative impact on communication between `before' and `now', irrespective of age and gender and largely independent of disease severity and duration, intelligibility and cognitive status. Activities of daily living (assessed by Unified Parkinson's Disease Rating Scale (UPDRS) II) and depression rating scale scores had the strongest association with change (adjusted R 2 0.27). There was a significant correlation between the rank order of perceived change in features examined in people with Parkinson's disease versus their carers, though in general carers rated change as having less impact.
Conclusions: Parkinson's disease exercises a strong influence on communication even before apparent alterations to intelligibility or motor status
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Impacts of hemispheric solar geoengineering on tropical cyclone frequency
Solar geoengineering refers to a range of proposed methods for counteracting global warming by artificially reducing sunlight at Earth’s surface. The most widely known SG proposal is stratospheric aerosol injection (SAI) which has impacts analogous to those from volcanic eruptions. Observations following major volcanic eruptions indicate that aerosol enhancements confined to a single hemisphere effectively modulate North Atlantic tropical cyclone (TC) activity in the following years. Here we investigate the effects of both single-hemisphere and global SAI scenarios on North Atlantic TC activity using the HadGEM2-ES general circulation model and various TC identification methods. We show that a robust result from all of the methods is that SAI applied to the southern hemisphere would enhance TC frequency relative to a global SAI application, and vice versa for SAI in the northern hemisphere. Our results reemphasize the perils of regional geoengineering and should motivate policymakers to regulate large-scale unilateral geoengineering deployments
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Adenovirus pseudo-outbreak in a large UK neonatal intensive care unit.
An unusually high number of positive adenovirus stool antigen tests were observed in neonatal samples from a large tertiary referral unit over a 10-week period, prompting the declaration of an outbreak and escalation of infection control precautions. Subsequent testing of original samples by alternative methods revealed a series of false-positive results. This is the first adenovirus pseudo-outbreak to be reported in the United Kingdom and the first to involve the Proflow Rotavirus-Adenovirus Combi test
Advection, diffusion and delivery over a network
Many biological, geophysical and technological systems involve the transport
of resource over a network. In this paper we present an algorithm for
calculating the exact concentration of resource at any point in space or time,
given that the resource in the network is lost or delivered out of the network
at a given rate, while being subject to advection and diffusion. We consider
the implications of advection, diffusion and delivery for simple models of
glucose delivery through a vascular network, and conclude that in certain
circumstances, increasing the volume of blood and the number of glucose
transporters can actually decrease the total rate of glucose delivery. We also
consider the case of empirically determined fungal networks, and analyze the
distribution of resource that emerges as such networks grow over time. Fungal
growth involves the expansion of fluid filled vessels, which necessarily
involves the movement of fluid. In three empirically determined fungal networks
we found that the minimum currents consistent with the observed growth would
effectively transport resource throughout the network over the time-scale of
growth. This suggests that in foraging fungi, the active transport mechanisms
observed in the growing tips may not be required for long range transport.Comment: 54 pages including appendix, 10 figure
Access to interpreting services in England: secondary analysis of national data
Background:
Overcoming language barriers to health care is a global challenge. There is great linguistic diversity in the major cities in the UK with more than 300 languages, excluding dialects, spoken by children in London alone. However, there is dearth of data on the number of non-English speakers for planning effective interpreting services. The aim was to estimate the number of people requiring language support amongst the minority ethnic communities in England.
Methods:
Secondary analysis of national representative sample of subjects recruited to the Health Surveys for England 1999 and 2004.
Results:
298,432 individuals from the four main minority ethnic communities (Indian, Pakistani, Bangladeshi and Chinese) who may be unable to communicate effectively with a health professional. This represents 2,520,885 general practice consultations per year where interpreting services might be required.
Conclusion:
Effective interpreting services are required to improve access and health outcomes of non-English speakers and thereby facilitate a reduction in health inequalities
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Intercomparison of long-term sea surface temperature analyses using the GHRSST Multi-Product Ensemble (GMPE) system
Six global, gridded, gap-free, daily sea surface temperature (SST) analyses covering a period of at least 20 years have been intercompared: ESA SST CCI anal- ysis long-term product v1.0, MyOcean OSTIA reanalysis v1.0, CMC 0.2 degree, AVHRR ONLY Daily 1/4 degree OISST v2.0, HadISST2.1.0.0 and MGDSST. A seventh SST product of the ensemble median of all six has also been produced using the GMPE (Group for High Resolution SST Multi-Product Ensemble) sys- tem. Validation against independent near-surface Argo data, a long timeseries of moored buoy data from the tropics and anomalies to the GMPE median have been used to examine the temporal and spatial homogeneity of the analyses. A comparison of the feature resolution of the analyses has also been undertaken. A summary of relative strengths and weaknesses of the SST datasets is presented, intended to help users to make an informed choice of which analysis is most suitable for their proposed application
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Speciation and milk adulteration analysis by rapid ambient liquid MALDI mass spectrometry profiling using machine learning
Growing interest in food quality and traceability by regulators as well as consumers demands advances in more rapid, versatile and cost-effective analytical methods. Milk, as most food matrices, is a heterogeneous mixture composed of metabolites, lipids and proteins. One of the major challenges is to have simultaneous, quantitative detection (profiling) of this panel of biomolecules to gather valuable information for assessing food quality, traceability and safety.
Here, for milk analysis, atmospheric pressure (AP) matrix-assisted laser desorption/ionization (MALDI) employing homogenous liquid sample droplets was used on a Q-TOF mass analyzer. This method has the capability to produce multiply charged proteinaceous ions as well as highly informative profiles of singly charged lipids/metabolites.
In two examples, this method is coupled with user-friendly machine-learning software. First, rapid speciation of milk (cow, goat, sheep and camel) is demonstrated with 100% classification accuracy. Second, the detection of cow milk as adulterant in goat milk is shown at concentrations as low as 5% with 92.5% sensitivity and 94.5% specificity
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LAP-MALDI MS coupled with machine learning: an ambient mass spectrometry approach for high-throughput diagnostics
Large-scale population screening for early and accurate detection of disease is a key objective for future diagnostics. Ideally, diagnostic tests that achieve this goal are also cost-effective, fast and easily adaptable to new diseases with the potential of multiplexing. Mass spectrometry (MS), particularly MALDI MS profiling, has been explored for many years in disease diagnostics, most successfully in clinical microbiology but less in early detection of diseases. Here, we present liquid atmospheric pressure (LAP)-MALDI MS profiling as a rapid, large-scale and cost-effective analysis platform for multiplexing disease analysis. Using this new platform, two different types of tests exemplify its potential in early disease diagnosis and response to therapy. First, it is shown that LAP-MALDI MS profiling detects bovine mastitis two days before its clinical manifestation with a sensitivity of up to 70% and a specificity of up to 100%. This highly accurate, pre-symptomatic detection is demonstrated by using a large set of milk samples collected weekly over six months from approximately 500 dairy cows. Second, the potential of LAP-MALDI MS in antimicrobial resistance (AMR) detection is shown by employing the same mass spectrometric setup and similarly simple sample preparation as for the early detection of mastitis
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