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Oxidative stress occurs when antioxidant defence mechanisms are overwhelmed by free radicals and may lead to damage to DNA, which has been implicated in processes such as ageing and cancer. The Comet assay allows detection of oxidative DNA damage in individual cells. As horses with recurrent airway obstruction (RAO) have been shown to demonstrate low antioxidant status and oxidative stress, we hypothesised that peripheral blood mononuclear cells (PBMC) of horses with RAO would demonstrate increases in DNA damage following natural allergen challenge.
Six horses (mean age 15 years, range 8-23 years) diagnosed with RAO (in remission) and 6 healthy breed matched controls (mean age 9 years, range 5-15 years) were studied. Blood samples were collected 7 days prior to challenge and immediately and 3 days after stabling on mouldy hay and straw for 24h. All animals were kept at grass prior to and after the challenge period. Bronchoalveolar lavage (BAL) was performed and neutrophil counts determined.
Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of -0.49 and -0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.
We report new results from a program which is aimed at obtaining deep CCD photometry for a sample of relatively nearby globular clusters having a wide range of metallicities. The CCD cameras on the CFHT 3.6 m, CTIO 4 m and KPNO 4 m telescopes have been used over the past 4 years to obtain deep exposures in regions of a number of clusters. In order to avoid the severest crowding, all of our observations have been obtained at distances of greater than ~ 5 core radii from the cluster centers. The images have been analysed by using the DAOPHOT point-spread-function fitting routines.
Syndromic surveillance systems in England have demonstrated utility in the early identification of seasonal gastrointestinal illness (GI) tracking its spatio-temporal distribution and enabling early public health action. There would be additional public health utility if syndromic surveillance systems could detect or track subnational infectious disease outbreaks. To investigate using syndromic surveillance for this purpose we retrospectively identified eight large GI outbreaks between 2009 and 2014 (four randomly and four purposively sampled). We then examined syndromic surveillance information prospectively collected by the Real-time Syndromic Surveillance team within Public Health England for evidence of possible outbreak-related changes. None of the outbreaks were identified contemporaneously and no alerts were made to relevant public health teams. Retrospectively, two of the outbreaks – which happened at similar times and in proximal geographical locations – demonstrated changes in the local trends of relevant syndromic indicators and exhibited a clustering of statistical alarms, but did not warrant alerting local health protection teams. Our suite of syndromic surveillance systems may be more suited to their original purposes than as means of detecting or monitoring localized, subnational GI outbreaks. This should, however, be considered in the context of this study's limitations; further prospective work is needed to fully explore the use of syndromic surveillance for this purpose. Provided geographical coverage is sufficient, syndromic surveillance systems could be able to provide reassurance of no or minor excess healthcare systems usage during localized GI incidents.
Major depressive disorder (MDD) is moderately heritable, however genome-wide association studies (GWAS) for MDD, as well as for related continuous outcomes, have not shown consistent results. Attempts to elucidate the genetic basis of MDD may be hindered by heterogeneity in diagnosis. The Center for Epidemiological Studies Depression (CES-D) scale provides a widely used tool for measuring depressive symptoms clustered in four different domains which can be combined together into a total score but also can be analysed as separate symptom domains.
We performed a meta-analysis of GWAS of the CES-D symptom clusters. We recruited 12 cohorts with the 20- or 10-item CES-D scale (32 528 persons).
One single nucleotide polymorphism (SNP), rs713224, located near the brain-expressed melatonin receptor (MTNR1A) gene, was associated with the somatic complaints domain of depression symptoms, with borderline genome-wide significance (pdiscovery = 3.82 × 10−8). The SNP was analysed in an additional five cohorts comprising the replication sample (6813 persons). However, the association was not consistent among the replication sample (pdiscovery+replication = 1.10 × 10−6) with evidence of heterogeneity.
Despite the effort to harmonize the phenotypes across cohorts and participants, our study is still underpowered to detect consistent association for depression, even by means of symptom classification. On the contrary, the SNP-based heritability and co-heritability estimation results suggest that a very minor part of the variation could be captured by GWAS, explaining the reason of sparse findings.
We analyze the trajectory of near-Earth asteroid 2009~BD, which is a candidate target of the NASA Asteroid Redirect Mission. The small size of 2009 BD and its Earth-like orbit pose challenges to understanding the dynamical properties of 2009 BD. In particular, nongravitational perturbations, such as solar radiation pressure and the Yarkovsky effect, are essential to match observational data and provide reliable predictions. By using Spitzer Space Telescope IRAC observations and our model for the thermophysical properties and the nongravitational forces acting on 2009 BD we obtain probabilistic derivations of the physical properties of this object. We find two physically possible solutions. The first solution shows 2009 BD as a 2.9 ± 0.3 m diameter rocky body with an extremely high albedo that is covered with regolith-like material, causing it to exhibit a low thermal inertia. The second solution suggests 2009 BD to be a 4 ± 1 m diameter asteroid with albedo 0.45 ± 0.35 that consists of a collection of individual bare rock slabs. We are unable to rule out either solution based on physical reasoning. 2009 BD is the smallest asteroid for which physical properties have been constrained, providing unique information on the physical properties of objects in the size range smaller than 10 m.
We are developing a purely commensal survey experiment for fast (<5 s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest single events in the Universe. Our objective is to cover the enormous volume of transients parameter space made available by ASKAP, with an unprecedented combination of sensitivity and field of view. Fast timescale transients open new vistas on the physics of high brightness temperature emission, extreme states of matter and the physics of strong gravitational fields. In addition, the detection of extragalactic objects affords us an entirely new and extremely sensitive probe on the huge reservoir of baryons present in the IGM. We outline here our approach to the considerable challenge involved in detecting fast transients, particularly the development of hardware fast enough to dedisperse and search the ASKAP data stream at or near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of the key technologies and survey modes proposed for high time resolution science with the SKA.
Analytical round robins were established to allow laboratories responsible
for the analysis of (nuclear) wastes glasses to compare their analytical
capabilities and techniques with one another in a non-competitive
atmosphere. In addition the quality of analyses using different analytical
techniques on the same materials could be compared. Analytical Round Robin 7
had two primary objectives: 1) to evaluate the effect of using the same
analytical reference glass as a reference standard for bias correcting
analytical results for all the participating laboratories in making the
analyses; and 2) to discuss the analytical methods and results from the
participating laboratories between the participants for the purpose of
evaluating quality and interlaboratory consistency. This paper will
primarily address the first objective.
The purpose of an analytical reference material is to bring the analytical
results from various laboratories into better agreement by providing them a
common reference point No reference glass is likely to be ideal for each
element in the glass being analyzed. Obviously, the closer the reference
material is to the unknown, the more confidence there will be in the results
because less judgement is called for. Use of the reference glass to bias
correct analytical results for a standard set of analyses from several
laboratories provides the data needed to determine the effectiveness of an
Analytical Reference Glass (ARG) in producing interlaboratory agreement.
Concurrently, whether or not the analytical results using ARG-1 are more
valid or systematically biased can be evaluated using standard statistical
methods. The conclusion is that bias correcting with a standard glass such
as ARG-1 for results obtained by the inductively coupled plasma - atomic
emission spectroscopy (ICP-AES) analytical technique produces more accurate
The material-dependent manner in which ion damage occurs in AlAs/GaAs heteroepitaxial structures is demonstrated using conventional and high resolution transmission electron microscopy. Both 150keV and 2MeV Si+ ion implants are employed over a wide range of ion doses. Under conditions which yield rapid build-up of lattice damage in GaAs, the AlAs is found to be relatively resistant to structure breakdown. Indeed, the crystalline AlAs exerts a novel protective effect on immediately adjacent regions of the GaAs layers. For high implantation doses amorphous-crystal superlattices are formed in multilayer structures. For the highest ion doses the AlAs lattice begins to be disrupted by a characteristic, boundary-dependent, heterogeneous mechanism. These observations suggest that mobile point defects play a significant role in AlAs in situ restructuring processes.
A pulsed excimer laser was used to ablate aluminum metal into an oxygen-containing atmosphere. The resulting fine powder was collected on a 0.1 μm filter and analyzed to determine structure and composition. Using a combination of TEM, EELS, and thermal analysis techniques, the product was found to be amorphous aluminum oxide, Al2O3. The morphology of the powders was investigated using SEM, TEM, and surface area measurements. The resulting powder was crystallized and examined by x-ray diffraction.
Electron-beam lithography that has the capability of writing high-resolution nanometer features in semiconductors will be required to fabricate next-generation quantum scale devices, such as nanometer gate mini-FET's, lateral quantum-well arrays, or metal grid radiators,which have feature sizes from 100 nm (1000 A) to 15 nm (150 A). A Philips EM 420T scanning transmission, electron microscope (STEM) has been modified to write nanometersize features in gallium arsenide. For this STEM we have developed a high-speed beam blanker and pattern generator (PG) that is resist speed limited. The maximum writing field size is 100 by 100 micrometers; within this field size, the smallest addressable step is approximately 1.8 nm (18 A). A HP-9845 is used to supply data for the PG and for computer-aided design of the devices to be written. Pattern transfer from the resist to GaAs is completed by using the liftoff method. As a result of this capability, we have patterned more than one million dots in a prototype 80 by 80 micrometer solid state radiator. The dots have diameters down to 15 nm (150 A), which requires an e-beam writing time of less than 30 minutes.
The growth of strained, continuous Si1-xGex epitaxial alloy layers on Si can, under certain conditions, result in the occurrence of marked, small-scale layer thickness fluctuations in the form of crystallographically-aligned, interlocking ripple arrays. In the present work, combined transmission electron microscope (TEM) and atomic force microscope studies are employed to reveal the detailed nature of these surface ripples. TEM contrast studies demonstrate that well-defined, oscillatory strain variations accompany these ripple structures, the presence of which is shown to be associated with partial elastic strain-relief and lowering of the energy of die strained-layer system.
The methods for computer simulation of grain boundaries and hetero-interfaces in ceramics have long been available. We review developments in the field in two areas; the study of general grain boundaries and the simulation of hetero-interfaces. In both cases we discuss extrapolation from the symmetric case. We will also consider the validity of the continued use of classical potential models in an age of large-scale quantum calculations.