2,245 research outputs found
Silicone Additive Manufactured Indices Performed from a Virtual Diagnostic Waxing for Direct Composite Diastema Closure Combined with Resin Infiltration Technique on White Spot Lesions: A Case Report
The present article describes the resin infiltration technique to address white spots lesions presented on anterior and premolar teeth of a young patient after orthodontic treatment and the digital workflow for planning a diastema closure on the maxillary anterior teeth using facial photographs, an intraoral scanner, a facially driven diagnostic waxing using a dental computer-aided design (CAD) software, and 3-piece additive manufactured (AM) clear silicone indices. The virtual design of the silicone indices was completed using an open-source CAD software and included a flexible clear buccal piece, flexible clear lingual piece, and rigid clear custom tray. The unique 3-piece index design allows a horizontal path of insertion, controlled uniform thickness of the indices, flexible and rigid material properties combination, accurate translation of the diagnostic waxing into the patient´s mouth, and digital storage of the designs
Tunable DNA Hybridization Enables Spatially and Temporally Controlled Surface-Anchoring of Biomolecular Cargo
The controlled immobilization of biomolecules onto surfaces is relevant in biosensing and cell biological research. Spatial control is achieved by surface-tethering molecules in micro- or nanoscale patterns. Yet, there is an increasing demand for temporal control over how long biomolecular cargo stays immobilized until released into the medium. Here, we present a DNA hybridization-based approach to reversibly anchor biomolecular cargo onto micropatterned surfaces. Cargo is linked to a DNA oligonucleotide that hybridizes to a sequence-complementary, surface-tethered strand. The cargo is released from the substrate by the addition of an oligonucleotide that disrupts the duplex interaction via toehold-mediated strand displacement. The unbound tether strand can be reloaded. The generic strategy is implemented with small-molecule or protein cargo, varying DNA sequences, and multiple surface patterning routes. The approach may be used as a tool in biological research to switch membrane proteins from a locally fixed to a free state, or in biosensing to shed biomolecular receptors to regenerate the sensor surface
NLO QCD corrections to WZ+jet production with leptonic decays
We compute the next-to-leading order QCD corrections to WZ+jet production at
the Tevatron and the LHC, including decays of the electroweak bosons to light
leptons with all off-shell effects taken into account. The corrections are
sizable and have significant impact on the differential distributions.Comment: 14 pages, 7 figure
Optical detection of single non-absorbing molecules using the surface plasmon of a gold nanorod
Current optical detection schemes for single molecules require light
absorption, either to produce fluorescence or direct absorption signals. This
severely limits the range of molecules that can be detected, because most
molecules are purely refractive. Metal nanoparticles or dielectric resonators
detect non-absorbing molecules by a resonance shift in response to a local
perturbation of the refractive index, but neither has reached single-protein
sensitivity. The most sensitive plasmon sensors to date detect single molecules
only when the plasmon shift is amplified by a highly polarizable label or by a
localized precipitation reaction on the particle's surface. Without
amplification, the sensitivity only allows for the statistical detection of
single molecules. Here we demonstrate plasmonic detection of single molecules
in realtime, without the need for labeling or amplification. We monitor the
plasmon resonance of a single gold nanorod with a sensitive photothermal assay
and achieve a ~ 700-fold increase in sensitivity compared to state-of-the-art
plasmon sensors. We find that the sensitivity of the sensor is intrinsically
limited due to spectral diffusion of the SPR. We believe this is the first
optical technique that detects single molecules purely by their refractive
index, without any need for photon absorption by the molecule. The small size,
bio-compatibility and straightforward surface chemistry of gold nanorods may
open the way to the selective and local detection of purely refractive proteins
in live cells
Latest Results from the Heidelberg-Moscow Double Beta Decay Experiment
New results for the double beta decay of 76Ge are presented. They are
extracted from Data obtained with the HEIDELBERG-MOSCOW, which operates five
enriched 76Ge detectors in an extreme low-level environment in the GRAN SASSO.
The two neutrino accompanied double beta decay is evaluated for the first time
for all five detectors with a statistical significance of 47.7 kg y resulting
in a half life of (T_(1/2))^(2nu) = [1.55 +- 0.01 (stat) (+0.19) (-0.15)
(syst)] x 10^(21) years. The lower limit on the half-life of the 0nu beta-beta
decay obtained with pulse shape analysis is (T_(1/2))^(0_nu) > 1.9 x 10^(25)
[3.1 x 10^(25)] years with 90% C.L. (68% C.L.) (with 35.5 kg y). This results
in an upper limit of the effective Majorana neutrino mass of 0.35 eV (0.27 eV).
No evidence for a Majoron emitting decay mode or for the neutrinoless mode is
observed.Comment: 14 pages, revtex, 6 figures, Talk was presented at third
International Conference ' Dark Matter in Astro and Particle Physics' -
DARK2000, to be publ. in Proc. of DARK2000, Springer (2000). Please look into
our HEIDELBERG Non-Accelerator Particle Physics group home page:
http://www.mpi-hd.mpg.de/non_acc
The role of chaotic resonances in the solar system
Our understanding of the Solar System has been revolutionized over the past
decade by the finding that the orbits of the planets are inherently chaotic. In
extreme cases, chaotic motions can change the relative positions of the planets
around stars, and even eject a planet from a system. Moreover, the spin axis of
a planet-Earth's spin axis regulates our seasons-may evolve chaotically, with
adverse effects on the climates of otherwise biologically interesting planets.
Some of the recently discovered extrasolar planetary systems contain multiple
planets, and it is likely that some of these are chaotic as well.Comment: 28 pages, 9 figure
Vaccination against Foot-and-mouth disease : do initial conditions affect its benefit?
When facing incursion of a major livestock infectious disease, the decision to implement a vaccination programme is made at the national level. To make this decision, governments must consider whether the benefits of vaccination are sufficient to outweigh potential additional costs, including further trade restrictions that may be imposed due to the implementation of vaccination. However, little consensus exists on the factors triggering its implementation on the field. This work explores the effect of several triggers in the implementation of a reactive vaccination-to-live policy when facing epidemics of foot-and-mouth disease. In particular, we tested whether changes in the location of the incursion and the delay of implementation would affect the epidemiological benefit of such a policy in the context of Scotland. To reach this goal, we used a spatial, premises-based model that has been extensively used to investigate the effectiveness of mitigation procedures in Great Britain. The results show that the decision to vaccinate, or not, is not straightforward and strongly depends on the underlying local structure of the population-at-risk. With regards to disease incursion preparedness, simply identifying areas of highest population density may not capture all complexities that may influence the spread of disease as well as the benefit of implementing vaccination. However, if a decision to vaccinate is made, we show that delaying its implementation in the field may markedly reduce its benefit. This work provides guidelines to support policy makers in their decision to implement, or not, a vaccination-to-live policy when facing epidemics of infectious livestock disease
Should patients with abnormal liver function tests in primary care be tested for chronic viral hepatitis: cost minimisation analysis based on a comprehensively tested cohort
Background
Liver function tests (LFTs) are ordered in large numbers in primary care, and the Birmingham and Lambeth Liver Evaluation Testing Strategies (BALLETS) study was set up to assess their usefulness in patients with no pre-existing or self-evident liver disease. All patients were tested for chronic viral hepatitis thereby providing an opportunity to compare various strategies for detection of this serious treatable disease.
Methods
This study uses data from the BALLETS cohort to compare various testing strategies for viral hepatitis in patients who had received an abnormal LFT result. The aim was to inform a strategy for identification of patients with chronic viral hepatitis. We used a cost-minimisation analysis to define a base case and then calculated the incremental cost per case detected to inform a strategy that could guide testing for chronic viral hepatitis.
Results
Of the 1,236 study patients with an abnormal LFT, 13 had chronic viral hepatitis (nine hepatitis B and four hepatitis C). The strategy advocated by the current guidelines (repeating the LFT with a view to testing for specific disease if it remained abnormal) was less efficient (more expensive per case detected) than a simple policy of testing all patients for viral hepatitis without repeating LFTs. A more selective strategy of viral testing all patients for viral hepatitis if they were born in countries where viral hepatitis was prevalent provided high efficiency with little loss of sensitivity. A notably high alanine aminotransferase (ALT) level (greater than twice the upper limit of normal) on the initial ALT test had high predictive value, but was insensitive, missing half the cases of viral infection.
Conclusions
Based on this analysis and on widely accepted clinical principles, a "fast and frugal" heuristic was produced to guide general practitioners with respect to diagnosing cases of viral hepatitis in asymptomatic patients with abnormal LFTs. It recommends testing all patients where a clear clinical indication of infection is present (e.g. evidence of intravenous drug use), followed by testing all patients who originated from countries where viral hepatitis is prevalent, and finally testing those who have a notably raised ALT level (more than twice the upper limit of normal). Patients not picked up by this efficient algorithm had a risk of chronic viral hepatitis that is lower than the general population
Noninvasive assessment of asthma severity using pulse oximeter plethysmograph estimate of pulsus paradoxus physiology
<p>Abstract</p> <p>Background</p> <p>Pulsus paradoxus estimated by dynamic change in area under the oximeter plethysmograph waveform (PEP) might provide a measure of acute asthma severity. Our primary objective was to determine how well PEP correlates with forced expiratory volume in 1-second (%FEV<sub>1</sub>) (criterion validity) and change of %FEV<sub>1 </sub>(responsiveness) during treatment in pediatric patients with acute asthma exacerbations.</p> <p>Methods</p> <p>We prospectively studied subjects 5 to 17 years of age with asthma exacerbations. PEP, %FEV<sub>1</sub>, airway resistance and accessory muscle use were recorded at baseline and at 2 and 4 hours after initiation of corticosteroid and bronchodilator treatments. Statistical associations were tested with Pearson or Spearman rank correlations, logistic regression using generalized estimating equations, or Wilcoxon rank sum tests.</p> <p>Results</p> <p>We studied 219 subjects (median age 9 years; male 62%; African-American 56%). Correlation of PEP with %FEV<sub>1 </sub>demonstrated criterion validity (r = - 0.44, 95% confidence interval [CI], - 0.56 to - 0.30) and responsiveness at 2 hours (r = - 0.31, 95% CI, - 0.50 to - 0.09) and 4 hours (r = - 0.38, 95% CI, - 0.62 to - 0.07). PEP also correlated with airway resistance at baseline (r = 0.28 for ages 5 to 10; r = 0.45 for ages 10 to 17), but not with change over time. PEP was associated with accessory muscle use (OR 1.16, 95% CI, 1.11 to 1.21, P < 0.0001).</p> <p>Conclusions</p> <p>PEP demonstrates criterion validity and responsiveness in correlations with %FEV<sub>1</sub>. PEP correlates with airway resistance at baseline and is associated with accessory muscle use at baseline and at 2 and 4 hours after initiation of treatment. Incorporation of this technology into contemporary pulse oximeters may provide clinicians improved parameters with which to make clinical assessments of asthma severity and response to treatment, particularly in patients who cannot perform spirometry because of young age or severity of illness. It might also allow for earlier recognition and improved management of other disorders leading to elevated pulsus paradoxus.</p
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