1,673 research outputs found
Design and Control of a Flight-Style AUV with Hovering Capability
The small flight-style Delphin AUV is designed to evaluate the performance of a long range survey AUV with the additional capability to hover and manoeuvre at slow speed. Delphinâs hull form is based on a scaled version of Autosub6000, and in addition to the main thruster and control surfaces at the rear of the vehicle, Delphin is equipped with four rim driven tunnel thrusters. In order to reduce the development cycle time, Delphin was designed to use commercial-off-the-shelf (COTS) sensors and thrusters interfaced to a standard PC motherboard running the control software within the MS Windows environment. To further simplify the development, the autonomy system uses the State-Flow Toolbox within the Matlab/Simulink environment. While the autonomy software is running, image processing routines are used for obstacle avoidance and target tracking, within the commercial Scorpion Vision software. This runs as a parallel thread and passes results to Matlab via the TCP/IP communication protocol. The COTS based development approach has proved effective. However, a powerful PC is required to effectively run Matlab and Simulink, and, due to the nature of the Windows environment, it is impossible to run the control in hard real-time. The autonomy system will be recoded to run under the Matlab Windows Real-Time Windows Target in the near future. Experimental results are used to demonstrating the performance and current capabilities of the vehicle are presented
Drug delivery in a tumour cord model: a computational simulation
YesThe tumour vasculature and microenvironment is complex and heterogeneous, contributing to reduced delivery of cancer drugs to the tumour. We have developed an in silico model of drug transport in a tumour cord to explore the effect of different drug regimes over a 72âh period and how changes in pharmacokinetic parameters affect tumour exposure to the cytotoxic drug doxorubicin. We used the model to describe the radial and axial distribution of drug in the tumour cord as a function of changes in the transport rate across the cell membrane, blood vessel and intercellular permeability, flow rate, and the binding and unbinding ratio of drug within the cancer cells. We explored how changes in these parameters may affect cellular exposure to drug. The model demonstrates the extent to which distance from the supplying vessel influences drug levels and the effect of dosing schedule in relation to saturation of drug-binding sites. It also shows the likely impact on drug distribution of the aberrant vasculature seen within tumours. The model can be adapted for other drugs and extended to include other parameters. The analysis confirms that computational models can play a role in understanding novel cancer therapies to optimize drug administration and delivery
Bounded and unitary elements in pro-C^*-algebras
A pro-C^*-algebra is a (projective) limit of C^*-algebras in the category of
topological *-algebras. From the perspective of non-commutative geometry,
pro-C^*-algebras can be seen as non-commutative k-spaces. An element of a
pro-C^*-algebra is bounded if there is a uniform bound for the norm of its
images under any continuous *-homomorphism into a C^*-algebra. The *-subalgebra
consisting of the bounded elements turns out to be a C^*-algebra. In this
paper, we investigate pro-C^*-algebras from a categorical point of view. We
study the functor (-)_b that assigns to a pro-C^*-algebra the C^*-algebra of
its bounded elements, which is the dual of the Stone-\v{C}ech-compactification.
We show that (-)_b is a coreflector, and it preserves exact sequences. A
generalization of the Gelfand-duality for commutative unital pro-C^*-algebras
is also presented.Comment: v2 (accepted
Flu-like and other systemic drug reactions among persons receiving weekly rifapentine plus isoniazid or daily isoniazid for treatment of latent tuberculosis infection in the PREVENT tuberculosis study
BACKGROUND:
Weekly rifapentine plus isoniazid for 3 months (3HP) is as effective as daily isoniazid for 9 months (9H) for latent tuberculosis infection in high-risk persons, but there have been reports of possible flu-like syndrome.
METHODS:
We identified clinically significant systemic drug reactions (SDR) and evaluated risk factors in patients who did not complete treatment in the PREVENT Tuberculosis study.
RESULTS:
Among 7552 persons who received â„1 dose of study drug, 153 had a SDR: 138/3893 (3.5%) with 3HP vs 15/3659 (0.4%) with 9H (P < .001). In the 3HP arm, 87 (63%) had flu-like syndrome and 23 (17%) had cutaneous reactions; 13/3893 (0.3%) had severe reactions (6 were hypotensive) and 6 reported syncope. Symptoms occurred after a median of 3 doses, and 4 hours after the dose; median time to resolution was 24 hours. There were no deaths. In multivariate logistic regression analysis, factors independently associated with SDR included receipt of 3HP (adjusted odds ratio [aOR] 9.4; 95% confidence interval [CI], 5.5, 16.2), white non-Hispanic race/ethnicity (aOR 3.3; 95% CI, 2.3, 4.7), female sex (aOR 2.0; 95% CI, 1.4, 2.9), age â„35 years (aOR 2.0; 95% CI, 1.4, 2.9), and lower body mass index (body mass index [BMI]; P = .009). In a separate multivariate analysis among persons who received 3HP, severe SDR were associated with white non-Hispanic race/ethnicity (aOR 5.4; 95% CI, 1.8, 16.3), and receipt of concomitant non-study medications (aOR 5.9; 95% CI, 1.3, 27.1).
CONCLUSIONS:
SDR were more common with 3HP, and mostly flu-like. Persons of white race, female sex, older age, and lower BMI were at increased risk. Severe reactions were rare and associated with 3HP, concomitant medication, and white race. The underlying mechanism is unclear
Radiation induced oscillatory Hall effect in high mobility GaAs/AlGaAs devices
We examine the radiation induced modification of the Hall effect in high
mobility GaAs/AlGaAs devices that exhibit vanishing resistance under microwave
excitation. The modification in the Hall effect upon irradiation is
characterized by (a) a small reduction in the slope of the Hall resistance
curve with respect to the dark value, (b) a periodic reduction in the magnitude
of the Hall resistance, , that correlates with an increase in the
diagonal resistance, , and (c) a Hall resistance correction that
disappears as the diagonal resistance vanishes.Comment: 4 pages text, 4 color figure
Recent Experimental Tests of Special Relativity
We review our recent Michelson-Morley (MM) and Kennedy-Thorndike (KT)
experiment, which tests Lorentz invariance in the photon sector, and report
first results of our ongoing atomic clock test of Lorentz invariance in the
matter sector. The MM-KT experiment compares a cryogenic microwave resonator to
a hydrogen maser, and has set the most stringent limit on a number of
parameters in alternative theories to special relativity. We also report first
results of a test of Lorentz invariance in the SME (Standard Model Extension)
matter sector, using Zeeman transitions in a laser cooled Cs atomic fountain
clock. We describe the experiment together with the theoretical model and
analysis. Recent experimental results are presented and we give a first
estimate of components of the parameters of the SME matter
sector. A full analysis of systematic effects is still in progress, and will be
the subject of a future publication together with our final results. If
confirmed, the present limits would correspond to first ever measurements of
some components, and improvements by 11 and 14 orders of
magnitude on others.Comment: 29 pages. Contribution to Springer Lecture Notes, "Special Relativity
- Will it survive the next 100 years ?", Proceedings, Potsdam, 200
Setdb1-mediated H3K9 methylation is enriched on the inactive X and plays a role in its epigenetic silencing
Background: The presence of histone 3 lysine 9 (H3K9) methylation on the mouse inactive X chromosome has been controversial over the last 15 years, and the functional role of H3K9 methylation in X chromosome inactivation in any species has remained largely unexplored. Results: Here we report the first genomic analysis of H3K9 di- and tri-methylation on the inactive X: we find they are enriched at the intergenic, gene poor regions of the inactive X, interspersed between H3K27 tri-methylation domains found in the gene dense regions. Although H3K9 methylation is predominantly non-genic, we find that depletion of H3K9 methylation via depletion of H3K9 methyltransferase Set domain bifurcated 1 (Setdb1) during the establishment of X inactivation, results in failure of silencing for around 150 genes on the inactive X. By contrast, we find a very minor role for Setdb1-mediated H3K9 methylation once X inactivation is fully established. In addition to failed gene silencing, we observed a specific failure to silence X-linked long-terminal repeat class repetitive elements. Conclusions: Here we have shown that H3K9 methylation clearly marks the murine inactive X chromosome. The role of this mark is most apparent during the establishment phase of gene silencing, with a more muted effect on maintenance of the silent state. Based on our data, we hypothesise that Setdb1-mediated H3K9 methylation plays a role in epigenetic silencing of the inactive X via silencing of the repeats, which itself facilitates gene silencing through alterations to the conformation of the whole inactive X chromosome.Andrew Keniry, Linden J. Gearing, Natasha Jansz, Joy Liu, Aliaksei Z. Holik, Peter F. Hickey, Sarah A. Kinkel, Darcy L. Moore, Kelsey Breslin, Kelan Chen, Ruijie Liu, Catherine Phillips, Miha Pakusch, Christine Biben, Julie M. Sheridan, Benjamin T. Kile, Catherine Carmichael, Matthew E. Ritchie, Douglas J. Hilton and Marnie E. Blewit
Ongoing Phase 1/2 Study Of Incb050465, A Selective Pi3kÎŽ Inhibitor, For The Treatment Of Patients (Pts) With Relapsed/Refractory (R/R) BâCell Malignancies (Citadelâ101)
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137307/1/hon2438_139.pd
Spontaneous symmetry breaking in gauge theories via Bose-Einstein condensation
We propose a mechanism naturally leading to the spontaneous symmetry breaking
in a gauge theory. The Higgs field is assumed to have global and gauged
internal symmetries. We associate a non zero chemical potential to one of the
globally conserved charges commuting with all of the gauge transformations.
This induces a negative mass squared for the Higgs field triggering the
spontaneous symmetry breaking of the global and local symmetries. The mechanism
is general and we test the idea for the electroweak theory in which the Higgs
sector is extended to possess an extra global Abelian symmetry. To this
symmetry we associate a non zero chemical potential. The Bose-Einstein
condensation of the Higgs leads, at tree level, to modified dispersion
relations for the Higgs field while the dispersion relations of the gauge
bosons and fermions remain undisturbed. The latter are modified through higher
order corrections. We have computed some corrections to the vacuum
polarizations of the gauge bosons and fermions. To quantify the corrections to
the gauge boson vacuum polarizations with respect to the Standard Model we
considered the effects on the T parameter. We finally derive the one loop
modified fermion dispersion relations.Comment: RevTeX 4, 13 pages. Added references and corrected typo
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Large area black body source for ITER ECE in situ calibration
Development and testing of a hot calibration source for the ECE systems on ITER is underway. The source is intended to meet the requirements described in DDD55 Overview of Diagnostics. The requirement is for two 200 mm diameter sources. One will operate at atmospheric pressure and be well removed from the experiment. The other will operate in vacuum near the plasma. Both will operate at temperatures up to 800 °C. Here we report on the development of a prototype hot calibration source and of a realistic thermal model of the hot calibration source that will be used in simulations of the thermal properties of the source. Selection of a reliable heating method is challenging. Heating methods under consideration will be discussed.Center for Electromechanic
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