1,362 research outputs found
Real-time sweat pH monitoring based on a wearable chemical barcode micro-fluidic platform incorporating ionic liquids
This work presents the fabrication, characterisation and the performance of a wearable, robust, flexible
and disposable chemical barcode device based on a micro-fluidic platform that incorporates ionic
liquid polymer gels (ionogels). The device has been applied to the monitoring of the pH of sweat in
real time during an exercise period. The device is an ideal wearable sensor for measuring the pH of
sweat since it does not contents any electronic part for fluidic handle or pH detection and because it can
be directly incorporated into clothing, head- or wristbands, which are in continuous contact with the
skin. In addition, due to the micro-fluidic structure, fresh sweat is continuously passing through the sensing area providing the capability to perform continuous real time analysis. The approach presented here ensures immediate feedback regarding sweat composition. Sweat analysis is attractive for monitoring purposes as it can provide physiological information directly relevant to the health and performance of the wearer without the need for an invasive sampling approac
Substellar companions and the formation of hot subdwarf stars
"Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics."We give a brief review over the observational evidence for close substellar companions to hot subdwarf stars. The formation of these core helium-burning objects requires huge mass loss of their red giant progenitors. It has been suggested that besides stellar companions substellar objects in close orbits may be able to trigger this mass loss. Such objects can be easily detected around hot subdwarf stars by medium or high resolution spectroscopy with an RV accuracy at the km s(-1)-level. Eclipsing systems of Vir type stick out of transit surveys because of their characteristic light curves. The best evidence that substellar objects in close orbits around sdBs exist and that they are able to trigger the required mass loss is provided by the eclipsing system SDSS J0820+0008, which was found in the course of the MUCHFUSS project. Furthermore, several candidate systems have been discovered.Final Accepted Versio
The Pl(A2) polymorphism of integrin beta(3) enhances outside-in signaling and adhesive functions.
Genetic factors are believed to influence the development of arterial thromboses. Because integrin alpha(IIb)beta(3) plays a crucial role in thrombus formation, we analyzed receptor adhesive properties using Chinese hamster ovary and human kidney embryonal 293 cells overexpressing the Pl(A1) or Pl(A2) polymorphic forms of alpha(IIb)beta(3). Soluble fibrinogen binding was no different between Pl(A1) and Pl(A2) cells, either in a resting state or when alpha(IIb)beta(3) was activated with anti-LIBS6. Pl(A1) and Pl(A2) cells bound equivalently to immobilized fibronectin. In contrast, significantly more Pl(A2) cells bound to immobilized fibrinogen in an alpha(IIb)beta(3)-dependent manner than did Pl(A1) cells. Disruption of the actin cytoskeleton by cytochalasin D abolished the increased binding of Pl(A2) cells. Compared with Pl(A1) cells, Pl(A2) cells exhibited a greater extent of polymerized actin and cell spreading, enhanced tyrosine phosphorylation of pp125(FAK), and greater fibrin clot retraction. These adhesion differences appear to depend on a signaling mechanism sensitive to receptor occupancy. Thus, the Pl(A2) polymorphism altered integrin-mediated functions of adhesion, spreading, actin cytoskeleton rearrangement, and clot retraction
Quantifying increased rates of erosive tooth wear progression in the early permanent dentition
Objectives
To investigate if quantitative analysis of intraoral scans of study models can identify erosive tooth wear progression.
Methods
Data were collected from a retrospective longitudinal study, using pre-and post-orthodontic treatment casts of 11−13 year olds, recorded at two consecutive appointments 29 months apart. Casts were digitised with intra-oral scanner TRIOS™ (3Shape, Copenhagen, Denmark) and first molar scan pairs used for analysis. Occlusal surfaces of each molar pair were visually assessed using the BEWE index as having no BEWE progression (n = 42) or BEWE progression (n = 54). Scan pairs were aligned and analysed for volume loss, maximum profile loss and mean profile loss in WearCompare (Leedsdigitaldentistry.com/wearcompare) using previously published protocols. Data were analysed in SPSS and not normal. Mann-Whitney U test with a Bonferroni correction assessed differences between progression groups. Receiver-operating-characteristic (ROC) curves were used to identify the sensitivity and specificity of quantified wear progression rates at determining visual wear progression.
Results
Surfaces with visible progression demonstrated a median volume loss of -2.19 mm3 (IQR-3.65, -0.91) compared to a median volume loss of -0.37 mm3 (IQR -1.02, 0.16) in the no visible progression group (p < 0.001). Mean profile loss was -75.2 μm (IQR-93.9, -61.0) and 63.2 μm (IQR -82.5, -49.7) for the progression and no-progression groups respectively (p = 0.018). Volume loss of -1.22mm3 represented a 79 % sensitivity and 61 % specificity. The estimated area under the curve for volume loss was 0.80 (95 %CI 0.71-0.89, p < 0.001).
Conclusions
This is the first study to propose rates of high wear progression in adolescents. Limited sensitivity and specificity confirms that quantitative analysis is an adjunct tool to be used alongside history taking and clinical judgement.
Clinical Significance
The rapid advancement of digital technologies may result in improved diagnosis in erosive tooth wear (ETW). Intra-oral scans and registration software are a promising adjunct for monitoring ETW progression in clinical practice
Planetary detection limits taking into account stellar noise. I. Observational strategies to reduce stellar oscillation and granulation effects
The radial velocity signature of stellar noise is small, around the
meter-per-second, but already too much for the detection of Earth mass planets
in habitable zones. In this paper, we address the important role played by
observational strategies in averaging out the radial velocity signature of
stellar noise. We also derive the planetary mass detection limits expected in
presence of stellar noise. We start with HARPS asteroseismology measurements
for 4 stars (beta Hyi, alpha Cen A, mu Ara and tau Ceti) available in the ESO
archive plus very precise measurements of alpha Cen B. This sample covers
different spectral types, from G2 to K1 and different evolutionary stage, from
subgiant to dwarf stars. Since the span of our data ranges between 5 to 8 days,
we will have access to oscillation modes and granulation phenomena, without
important contribution of activity noise which is present at larger time
scales. For those 5 stars, we generate synthetic radial velocity measurements
after fitting corresponding models of stellar noise in Fourier space. These
measurements allows us to study the radial velocity variation due to stellar
noise for different observational strategies as well as the corresponding
planetary mass detection limits. Applying 3 measurements per night of 10
minutes exposure each, 2 hours apart, seems to average out most efficiently the
stellar noise considered. For quiet K1V stars as alpha Cen B, such a strategy
allows us to detect planets of ~3 times the mass of Earth with an orbital
period of 200 days, corresponding to the habitable zone of the star. Since
activity is not yet included in our simulation, these detection limits
correspond to a case, which exist, where the host star has few magnetic
features. In this case stellar noise is dominated by oscillation modes and
granulation phenomena.Comment: 12 pages, 6 figures, Accepted for publication in A&
Solar-like oscillations in the G2 subgiant beta Hydri from dual-site observations
We have observed oscillations in the nearby G2 subgiant star beta Hyi using
high-precision velocity observations obtained over more than a week with the
HARPS and UCLES spectrographs. The oscillation frequencies show a regular comb
structure, as expected for solar-like oscillations, but with several l=1 modes
being strongly affected by avoided crossings. The data, combined with those we
obtained five years earlier, allow us to identify 28 oscillation modes. By
scaling the large frequency separation from the Sun, we measure the mean
density of beta Hyi to an accuracy of 0.6%. The amplitudes of the oscillations
are about 2.5 times solar and the mode lifetime is 2.3 d. A detailed comparison
of the mixed l=1 modes with theoretical models should allow a precise estimate
of the age of the star.Comment: 13 pages, 14 figures, accepted by ApJ. Fixed minor typo (ref to Fig
14
Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools
With available Virtual Observatory tools, we looked for new bright blue high
proper motion objects in the entire sky: white dwarfs, hot subdwarfs, runaway
OB stars, and early-type stars in nearby young moving groups. We performed an
all-sky cross-match between the optical Tycho-2 and near-infrared 2MASS
catalogues with Aladin, and selected objects with proper motions >50mas/yr and
colours Vt-Ks<-0.5mag with TOPCAT. We also collected multi-wavelength
photometry, constructed the spectral energy distributions and estimated
effective temperatures from fits to atmospheric models with VOSA for the most
interesting targets. We assembled a sample of 32 bright blue high proper motion
objects, including ten sdO/B subdwarfs, nine DA white dwarfs, five young
early-type stars (two of which are runaway stars), two blue horizontal branch
stars, one star with poor information, and five objects reported for the first
time in this work. These last five objects have magnitudes Bt~11.0-11.6mag,
effective temperatures ~24,000-30,000K, and are located in the region of known
white dwarfs and hot subdwarfs in a reduced proper motion-colour diagram. We
confirmed the hot subdwarf nature of one of the new objects, Albus 5, with
public far-ultraviolet spectroscopic data obtained with FUSE.Comment: Published in Astronomy & Astrophysic
A database of whole-body action videos for the study of action, emotion, and untrustworthiness
We present a database of high-definition (HD) videos for the study of traits inferred from whole-body actions. Twenty-nine actors (19 female) were filmed performing different actions—walking, picking up a box, putting down a box, jumping, sitting down, and standing and acting—while conveying different traits, including four emotions (anger, fear, happiness, sadness), untrustworthiness, and neutral, where no specific trait was conveyed. For the actions conveying the four emotions and untrustworthiness, the actions were filmed multiple times, with the actor conveying the traits with different levels of intensity. In total, we made 2,783 action videos (in both two-dimensional and three-dimensional format), each lasting 7 s with a frame rate of 50 fps. All videos were filmed in a green-screen studio in order to isolate the action information from all contextual detail and to provide a flexible stimulus set for future use. In order to validate the traits conveyed by each action, we asked participants to rate each of the actions corresponding to the trait that the actor portrayed in the two-dimensional videos. To provide a useful database of stimuli of multiple actions conveying multiple traits, each video name contains information on the gender of the actor, the action executed, the trait conveyed, and the rating of its perceived intensity. All videos can be downloaded free at the following address: http://www-users.york.ac.uk/~neb506/databases.html. We discuss potential uses for the database in the analysis of the perception of whole-body actions
The analysis of facial beauty: an emerging area of research in pattern analysis
Much research presented recently supports the idea that the human perception of attractiveness is data-driven and largely irrespective of the perceiver. This suggests using pattern analysis techniques for beauty analysis. Several scientific papers on this subject are appearing in image processing, computer vision and pattern analysis contexts, or use techniques of these areas. In this paper, we will survey the recent studies on automatic analysis of facial beauty, and discuss research lines and practical application
Recognition of cancer warning signs and anticipated time to help-seeking in a population sample of adults in the UK
Background: Not recognising a symptom as suspicious is a common reason given by cancer patients for delayed help-seeking; but inevitably this is retrospective. We therefore investigated associations between recognition of warning signs for breast, colorectal and lung cancer and anticipated time to help-seeking for symptoms of each cancer.
Methods: Computer-assisted telephone interviews were conducted with a population-representative sample (N=6965) of UK adults age greater than or equal to50 years, using the Awareness and Beliefs about Cancer scale. Anticipated time to help-seeking for persistent cough, rectal bleeding and breast changes was categorised as >2 vs less than or equal to2 weeks. Recognition of persistent cough, unexplained bleeding and unexplained lump as cancer warning signs was assessed (yes/no). Associations between recognition and help-seeking were examined for each symptom controlling for demographics and perceived ease of health-care access.
Results: For each symptom, the odds of waiting for >2 weeks were significantly increased in those who did not recognise the related warning sign: breast changes: OR=2.45, 95% CI 1.47–4.08; rectal bleeding: OR=1.77, 1.36–2.30; persistent cough: OR=1.30, 1.17–1.46, independent of demographics and health-care access.
Conclusion: Recognition of warning signs was associated with anticipating faster help-seeking for potential symptoms of cancer. Strategies to improve recognition are likely to facilitate earlier diagnosis
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