743 research outputs found
Systemic inflammation and residual viraemia in HIV-positive adults on protease inhibitor monotherapy: a cross-sectional study.
Increased levels of markers of systemic inflammation have been associated with serious non-AIDS events even in patients on fully suppressive antiretroviral therapy. We explored residual viremia and systemic inflammation markers in patients effectively treated with ritonavir-boosted protease inhibitor monotherapy (PImono)
Financial abuse of older people in New Zealand
This working paper is linked to a workshop hosted by the Institute of Policy Studies, Victoria University of Wellington, in June 2011. Following discussion of definitional issues and exploration of what we know about FEA, we identify strategies to prevent and reduce FEA in New Zealand. Our purpose is to promote discussion and development of policies which ensure a multi-faceted response to this issue. This will help to ensure that older people are free from elder abuse in all its forms
Optical diffraction for measurements of nano-mechanical bending
Micromechanical transducers such as cantilevers for AFM often rely on optical
readout methods that require illumination of a specific region of the
microstructure. Here we explore and exploit the diffraction effects that have
been previously neglected when modeling cantilever bending measurement
techniques. The illumination of a cantilever end causes an asymmetric
diffraction pattern at the photodetector that significantly affects the
calibration of the signal in the popular optical beam deflection technique
(OBDT). Conditions for optimized linear signals that avoid detection artifacts
conflict with small numerical aperture illumination and narrow cantilevers
which are softer and therefore more sensitive. Embracing diffraction patterns
as a physical measurable allows a richer detection technique that decouples
measurements of tilt and curvature and simultaneously relaxes the requirements
on the alignment of illumination and detector. We show analytical results,
numerical simulations and physiologically relevant experimental data
demonstrating the usefulness of these diffraction features. We offer
experimental design guidelines and identify and quantify possible sources of
systematic error of up to 10% in OBDT. We demonstrate a new nanometre
resolution detection method that can replace OBDT, where Frauenhofer and Bragg
diffraction effects from finite sized and patterned cantilevers are exploited.
Such effects are readily generalized to arrays, and allow transmission
detection of mechanical curvature, enabling in-line instruments. In particular,
a cantilever with a periodic array of slots produces Bragg peaks which can be
analyzed to deduce the cantilever curvature. We highlight the comparative
advantages over OBDT by detecting molecular activity of antibiotic Vancomycin,
with an RMS noise equivalent to less than (1.5 nm), as example of
possible multi-maker bio-assays.Comment: 9 pages, 8 figure
Rapid antimicrobial sensitivity testing by single cell nanoscale optical interference
Growing antimicrobial resistance (AMR) is a serious global threat to human health, with estimates of AMR leading to 10 million deaths per year and costing the global economy $100tn by 20501,2. Current methods to detect resistance include phenotypic antibiotic sensitivity testing (AST) which measures bacterial growth and is therefore hampered by slow time to result (~12-24 hours). Therefore new rapid phenotypic methods for AST are urgently needed3. Here we describe a novel method for detecting phenotypic antibiotic resistance in ~45 minutes, capable of detecting single bacteria. The method uses a sensitive laser and detector system to measure nanoscale optical interference of single bacterial cells present in media, with simple sample preparation. This provides a read out of bacterial antibiotic resistance by detecting growth (resistant) or death (sensitive), much faster than current methods. We demonstrate the potential of this technique by determining resistance in both lab and clinical strains of E. coli, a key species for clinically burdensome urinary tract infections. This work provides the basis for a simple and fast diagnostic tool to detect antibiotic resistance in bacteria, reducing the health and economic burdens of AMR
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Temperature dependent stiffness and visco-elastic behaviour of lipid coated microbubbles using atomic force microscopy.
yesThe compression stiffness of a phospholipid microbubble was determined using force-spectroscopy as a function of temperature. The stiffness was found to decrease by approximately a factor of three from 0.08 N m 1, at 10 C, down to 0.03 N m 1 at 37 C. This temperature dependence indicates that the surface tension of lipid coating is the dominant contribution to the microbubble stiffness. The timedependent material properties, e.g. creep, increased non-linearly with temperature, showing a factor of two increase in creep-displacement, from 24 nm, at 10 C, to 50 nm, at 37 C. The standard linear solid model was used to extract the visco-elastic parameters and their determination at different temperatures allowed the first determination of the activation energy for creep, for a microbubble, to be determined.EPSR
Phase chirality and stereo-selective swelling of cholesteric elastomers
Cholesteric elastomers possess a macroscopic ``phase chirality'' as the
director n rotates in a helical fashion along an optical axis and can be
described by a chiral order parameter. This parameter can be tuned by changing
the helix pitch p and/or the elastic properties of the network. The
cholesterics also possess a local nematic order, changing with temperature or
during solvent swelling. In this paper, by measuring the power of optical
rotation, we discover how these two parameters vary as functions of temperature
or solvent adsorbed by the network. The main result is a finding of pronounced
stereo-selectivity of cholesteric elastomers, demonstrating itself in the
retention of the ``correct'' chirality component of a racemic solvent. It has
been possible to quantify the amount of such stereo-separation, as the basic
dynamics of the effect
Pica Behaviour and Positive Behavioural Support: Best Practice in assessment and intervention
Background: Pica (the ingestion of non-edible items) is a dangerous and relatively common behaviour presented by people with intellectual disabilities.
Method and materials: Non-systematic review of studies that are compatible with Positive Behavioural Support related to the definition, prevalence, assessment and intervention for PICA.
Results: PICA has a high prevalence in people with intellectual developmental disabilities and is potentially dangerous and multi-factorial in its causation. A range of suggested intervention strategies compatible with PBS were found with reported reductions in PICA ranging from 70-90% with a clear indication that multi-element interventions are likely to be the most effective.
Conclusions: Whilst the results reported in the studies reviewed are encouraging, there remain concerns regarding the feasibility of the implementation of these interventions and the extent to which the risk associated with PICA need to be managed even in the context of relatively effective interventions
Ground-based remote sensing of an elevated forest fire aerosol layer at Whistler, BC: implications for interpretation of mountaintop chemistry
On 30 August 2009, intense forest fires in interior British Columbia (BC)
coupled with winds from the east and northeast resulted in transport of a
broad forest fire plume across southwestern BC. The physico-chemical and
optical characteristics of the plume as observed from Saturna Island
(AERONET), CORALNet-UBC and the Whistler Mountain air chemistry facility
were consistent with forest fire plumes that have been observed elsewhere in
continental North America. However, the importance of three-dimensional
transport in relation to the interpretation of mountaintop chemistry
observations is highlighted on the basis of deployment of both a <i>CL31</i> ceilometer
and a single particle mass spectrometer (SPMS) in a mountainous setting. The
SPMS is used to identify the biomass plume based on levoglucosan and
potassium markers. Data from the SPMS are also used to show that the
biomass plume was correlated with nitrate, but not correlated with sulphate
or sodium. This study not only provides baseline measurements of biomass
burning plume physico-chemical characteristics in western Canada, but also
highlights the importance of lidar remote sensing methods in the
interpretation of mountaintop chemistry measurements
Trans-Pacific dust events observed at Whistler, British Columbia during INTEX-B
International audienceThe meteorology and physico-chemical characteristics of aerosol associated with two new cases of long range dust transport affecting western Canada during spring 2006 are described. Each event showed enhancements of both sulfate aerosol and crustal material of Asian origin. However, the events were of quite different character and demonstrate the highly variable nature of such events. The April event was a significant dust event with moderate sulfate enhancement while the May event was a weak dust event with very significant sulfate enhancement. The latter event was interesting in the sense that it was of short duration and was quickly followed by significant enhancement of organic material likely of regional origin. Comparison of these two events with other documented cases extending back to 1993, suggests that all dust events show coincident enhancements of sulfate and crustal aerosol. However, events vary across a wide continuum based on the magnitude of aerosol enhancements and their sulfate to calcium ratios. At one extreme, events are dominated by highly significant crustal enhancements (e.g. the well-documented 1998 and 2001 "dust" events) while at the other are events with some dust transport, but where sulfate enhancements are of very high magnitude (e.g. the 1993 event at Crater Lake and the 15 May 2006 event at Whistler). Other events represent a "mix". It is likely that this variability is a function of the comparative strengths of the dust and anthropogenic SO2 sources, the transport pathway and in particular the extent to which dust is transported across industrial SO2 sources, and finally, meteorological and chemical processes
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