1,152 research outputs found
Dean flow focusing and separation of small microspheres within a narrow size range.
Copyright The Author(s) 2014. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedRapid, selective particle separation and concentration within the bacterial size range (1â3 ÎŒm) in clinical or environmental samples promises significant improvements in detection of pathogenic microorganisms in areas including diagnostics and bio-defence. It has been proposed that microfluidic Dean flow-based separation might offer simple, efficient sample clean-up: separation of larger, bioassay contaminants to prepare bioassay targets including spores, viruses and proteins. However, reports are limited to focusing spherical particles with diameters of 5 ÎŒm or above. To evaluate Dean flow separation for (1â3 ÎŒm) range samples, we employ a 20 ÎŒm width and depth, spiral microchannel. We demonstrate focusing, separation and concentration of particles with closely spaced diameters of 2.1 and 3.2 ÎŒm, significantly smaller than previously reported as separated in Dean flow devices. The smallest target, represented by 1.0 ÎŒm particles, is not focused due to the high pressures associated with focussing particles of this size; however, it is cleaned of 93 % of 3.2 ÎŒm and 87 % of 2.1 ÎŒm microparticles. Concentration increases approaching 3.5 times, close to the maximum, were obtained for 3.2 ÎŒm particles at a flow rate of 10 ÎŒl minâ1. Increasing concentration degraded separation, commencing at significantly lower concentrations than previously predicted, particularly for particles on the limit of being focused. It was demonstrated that flow separation specificity can be fine-tuned by adjustment of output pressure differentials, improving separation of closely spaced particle sizes. We conclude that Dean flow separation techniques can be effectively applied to sample clean-up within this significant microorganism size range.Peer reviewedFinal Published versio
Sensitive Observations of Radio Recombination Lines in Orion and W51: The Data and Detection of Systematic Recombination Line Blueshifts Proportional to Impact Broadening
Sensitive spectral observations made in two frequency bands near 6.0 and 17.6
GHz are described for Orion and W51. Using frequency switching we were able to
achieve a dynamic range in excess of 10,000 without fitting sinusoidal or
polynomial baselines. This enabled us to detect lines as weak as T\Delta n$ as
high as 25 have been detected in Orion. In the Orion data, where the lines are
stronger, we have also detected a systematic shift in the line center
frequencies proportional to linewidth that cannot be explained by normal
optical depth effects.Comment: 22 pages, 13 figures. Accepted for publication in Astrophysics and
Space Scienc
Application of monolateral fixators as definitive treatment for tarsometatarsal joint injuries with lateral column shortening
Enabling participation of Black and Minority Ethnic (BME) and seldom-heard communities in health research: A case study from the SCAMP adolescent cohort study
Our inquiry investigated the barriers to, and facilitators for, the involvement of Black
and Minority Ethnic (BME) and âseldom-heardâ communities, in a study researching
the impact of mobile phone and wireless device usage on adolescentsâ cognition,
behaviour and mental health. The aim was to co-produce solutions to increase
participation, and we used focus groups, telephone interviews, a community event
and a public and patient involvement (PPI) café to conduct the inquiry. Five themes
emerged from the data: two enablers â the value and benefits of research; and
three barriers â concerns about research and about communication, and practical
constraints. A central cross-cutting theme, the concept of trust, was evident from
the data, and extended across all themes, including across the solutions to nonparticipation.
When the data collection and analysis were completed, we ran
a symposium for researchers and members of the public to share our findings
and to co-produce solutions. The symposium generated ideas about improving
participation, including tailoring participant information, engaging with local
advocates and involving people in research design and delivery
Dynamical description of quantum computing: generic nonlocality of quantum noise
We develop dynamical non-Markovian description of quantum computing in weak
coupling limit, in lowest order approximation. We show that long range memory
of quantum reservoir produces strong interrelation between structure of noise
and quantum algorithm, implying nonlocal attacks of noise. We then argue that
the quantum error correction method fails to protect quantum computation
against electromagnetic or phonon vacuum which exhibit memory. This
shows that the implicit assumption of quantum error correction theory --
independence of noise and self-dynamics -- fails in long time regimes. We also
use our approach to present {\it pure} decoherence and decoherence accompanied
by dissipation in terms of spectral density of reservoir. The so-called {\it
dynamical decoupling} method is discussed in this context. Finally, we propose
{\it minimal decoherence model}, in which the only source of decoherence is
vacuum. We optimize fidelity of quantum information processing under the
trade-off between speed of gate and strength of decoherence.Comment: 12 pages, minor corrections, softened interpretation of the result
The outsourcing of social care in Britain : what does it mean for voluntary sector workers?
While recent decades have witnessed a growth in the outsourcing of public services in Britain, the post-1997 UK Labour governments have sought to put in place mechanisms aimed at encouraging long-term collaborative contracting relationships marked by less reliance on cost-based competition. This article explores empirically how far these mechanisms have achieved their aims and thereby acted to protect the employment conditions of staff, and links this exploration to debates concerning the employment implications of organizational reforms within public sectors internationally. It concludes that in terms of bringing income security to the voluntary sector and stability to employment terms and conditions these efforts have been unsuccessful, and consequently casts doubts on more optimistic interpretations of the employment effects of organizational restructuring in the British public sector
The geometry of the higher dimensional black hole thermodynamics in Einstein-Gauss-Bonnet theory
This paper deals with five-dimensional black hole solutions in (a)
Einstein-Yang-Mills-Gauss-Bonnet theory and (b)Einstein-Maxwell-Gauss-Bonnet
theory with a cosmological constant for spherically symmetric space time. The
geometry of the black hole thermodynamics has been studied for both the black
holes.Comment: 8 page
A study of dye anchoring points in half-squarylium dyes for dye-sensitized solar cells
This paper reports the synthesis of a series of new half-squaraine dyes (Hf-SQ) based around a common chromophoric unit consisting of linked indoline and squaric acid moieties. Carboxylate groups have been incorporated onto this core structure at four different points to study the influence of the anchoring group position on dye-sensitized solar cell (DSC) device performance. Dyes have been linked to TiO2 directly through the squaric acid moiety, through a modified squaric acid unit where a vinyl dicyano group has replaced one carbonyl, via an alkyl carboxylate attached to the indole N or through a carboxylate attached to the 4 position of a benzyl indole. Contact angle measurements have been studied to investigate the hydrophobic/hydrophilic properties of the dyes and the results have been compared to N719 and Z907. Full characterization data of all the dyes and synthetic intermediates are reported including single-crystal X-ray structural analysis for dye precursors; the indole (2a) and the half-squarylium esters (3a) and (6b), as well as the dyes (4c), (8) and (12). Dye colours range from yellow to red/brown in solution (λmax range from 430 to 476 nm) with Δ ranging from 38â000 to 133â100 Mâ1 cmâ1. The performance of the dyes in DSCs shows the highest efficiency yet reported for a Hf-SQ dye (η = 5.0%) for 1 cm2 devices with a spectral response ranging from 400 to 700 nm depending on the dye substituents. Co-sensitization of half-squarylium dye (7b) with squaraine dye (SQ2) resulted in a broader spectral response and an improved device efficiency (η = 6.1%). Density functional theory (DFT) calculations and cyclic voltammetry have been used to study the influence of linker position on dye HOMOâLUMO levels and the data has been correlated with IâV and EQE data
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