8,899 research outputs found
Controlled crack growth specimen for brittle systems
A pure Mode 1 fracture specimen and test procedure has been developed which provides extended, stable, through-thickness crack growth in ceramics and other brittle, nonmetallic materials. Fixed displacement loading, applied at the crack mouth, promotes stable crack extension by reducing the stored elastic strain energy. Extremely fine control of applied displacements is achieved by utilizing the Poisson's expansion of a compressively loaded cylindrical pin. Stable cracks were successfully grown in soda-lime glass and monolithic Al2O3 for lengths in excess of 20 mm without uncontrollable catastrophic failure
Clinical and cost-effectiveness of capecitabine and tegafur with uracil for the treatment of metastatic colorectal cancer: systematic review and economic evaluation
Objectives:
To evaluate the clinical and costeffectiveness
of capecitabine and tegafur with uracil
(UFT/LV) as first-line treatments for patients with
metastatic colorectal cancer, as compared with 5-
fluorouracil/folinic acid (5-FU/FA) regimens.
Data sources: Electronic databases, reference lists of
relevant articles and sponsor submissions were also
consulted.
Review methods:
Systematic searches, selection
against criteria and quality assessment were performed
to obtain data from relevant studies. Costs were
estimated through resource-use data taken from the
published trials and the unpublished sponsor
submissions. Unit costs were taken from published
sources, where available. An economic evaluation was
undertaken to compare the cost-effectiveness of
capecitabine and UFT/LV with three intravenous 5-
FU/LV regimens widely used in the UK: the Mayo, the
modified de Gramont regimen and the inpatient de
Gramont regimens.
Results:
The evidence suggests that treatment with
capecitabine improves overall response rates and has
an improved adverse effect profile in comparison with
5-FU/LV treatment with the Mayo regimen, with the
exception of hand–foot syndrome. Time to disease
progression or death after treatment with UFT/LV in
one study appears to be shorter than after treatment
with 5-FU/LV with the Mayo regimen, although it also
had an improved adverse effect profile. Neither
capecitabine nor UFT/LV appeared to improve healthrelated
quality of life. Little information on patient
preference was available for UFT/LV, but there was
indicated a strong preference for this over 5-FU/LV.
The total cost of capecitabine and UFT/LV treatments
were estimated at £2111 and £3375, respectively,
compared with the total treatment cost for the Mayo
regimen of £3579. Cost estimates were also presented
for the modified de Gramont and inpatient de Gramont
regimens. These were £3684 and £6155, respectively.
No survival advantage was shown in the RCTs of the
oral drugs against the Mayo regimen. Cost savings of
capecitabine and UFT/LV over the Mayo regimen were
estimated to be £1461 and £209, respectively. Drug
acquisition costs were higher for the oral therapies
than for the Mayo regimen, but were offset by lower
administration costs. Adverse event treatment costs
were similar across the three regimens. It was inferred
that there was no survival difference between the oral
drugs and the de Gramont regimens. Cost savings of
capecitabine and UFT/LV over the modified de
Gramont regimen were estimated to be £1353 and
£101, respectively, and over the inpatient de Gramont
regimen were estimated to be £4123 and £2870,
respectively.
Conclusions:
The results show that there are cost
savings associated with the use of oral therapies. No
survival difference has been proven between the oral
drugs and the Mayo regimen. In addition, no evidence
of a survival difference between the Mayo regimen and
the de Gramont regimens has been identified.
However, improved progression-free survival and an
improved adverse event profile have been shown for
the de Gramont regimen over the Mayo regimen.
Further research is recommended into the following
areas: quality of life data should be included in trials of
colorectal cancer treatments; the place of effective oral
treatments in the treatment of colorectal cancer, the
safety mechanisms needed to ensure compliance and
the monitoring of adverse effects; the optimum
duration of treatment; the measurement of patient
preference; and a phase III comparative trial of
capecitabine and UFT/LV versus modified de Gramont
treatment to determine whether there was any survival
advantage and to collate the necessary economic data
Rehabilitation planning for small tanks in cascades: a methodology based on rapid assessment
Irrigation systems / Rehabilitation / Tank irrigation / Small-scale systems / Reservoirs / Conflict / Farmer participation / River Basin development / Water resources development / Arid zones / Sri Lanka
Assessing Multi-Unit Muscle Sympathetic Nerve Activity Across Groups: A Multivariate Approach to a Multivariate Concept
Baseline muscle sympathetic nerve activity (MSNA) comparisons of age (young & old, n=40) and cardiovascular disease (CVD) state (young: Y, old: O, metabolic syndrome: MET, coronary artery disease: CAD, chronic heart failure: CHF, n= 36) groups were made to assess which MSNA variable(s) best describe group differences using a MANOVA-based approach across 10 variables. The hypothesis that action potential (AP) variables would better discriminate between groups than integrated variables was not supported. Burst frequency and incidence together significantly differentiated between groups with variability attributed to spikes/min and spikes/100hb removed. Significant group differences were noted for these variables such that
Numerical calibration of the stable poisson loaded specimen
An analytical calibration of the Stable Poisson Loaded (SPL) specimen is presented. The specimen configuration is similar to the ASTM E-561 compact-tension specimen with displacement controlled wedge loading used for R-Curve determination. The crack mouth opening displacements (CMOD's) are produced by the diametral expansion of an axially compressed cylindrical pin located in the wake of a machined notch. Due to the unusual loading configuration, a three-dimensional finite element analysis was performed with gap elements simulating the contact between the pin and specimen. In this report, stress intensity factors, CMOD's, and crack displacement profiles are reported for different crack lengths and different contacting conditions. It was concluded that the computed stress intensity factor decreases sharply with increasing crack length, thus making the SPL specimen configuration attractive for fracture testing of brittle, high modulus materials
Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions
Analysis of biaxial texture of MgO films grown by ion-beam-assisted deposition (IBAD) has been performed using a quantitative reflection high-energy electron diffraction (RHEED) based method. MgO biaxial texture is determined by analysis of diffraction spot shapes from single RHEED images, and by measuring the width of RHEED in-plane rocking curves for MgO films grown on amorphous Si3N4 by IBAD using 750 eV Ar+ ions, at 45° incidence angle, and MgO e-beam evaporation. RHEED-based biaxial texture measurement accuracy is verified by comparison with in-plane and out-of-plane orientation distribution measurements made using transmission electron microscopy and x-ray rocking curves. In situ RHEED measurements also enable the analysis of the evolution of the biaxial texture which narrows with increasing film thickness. RHEED-based measurements of IBAD MgO biaxial texture show that the minimum in-plane orientation distribution depends on the out-of-plane orientation distribution, and indicates that the minimum obtainable in-plane orientation on distribution is 2°
Modelling of the Complex CASSOWARY/SLUGS Gravitational Lenses
We present the first high-resolution images of CSWA 31, a gravitational lens
system observed as part of the SLUGS (Sloan Lenses Unravelled by Gemini
Studies) program. These systems exhibit complex image structure with the
potential to strongly constrain the mass distribution of the massive lens
galaxies, as well as the complex morphology of the sources. In this paper, we
describe the strategy used to reconstruct the unlensed source profile and the
lens galaxy mass profiles. We introduce a prior distribution over
multi-wavelength sources that is realistic as a representation of our knowledge
about the surface brightness profiles of galaxies and groups of galaxies. To
carry out the inference computationally, we use Diffusive Nested Sampling, an
efficient variant of Nested Sampling that uses Markov Chain Monte Carlo (MCMC)
to sample the complex posterior distributions and compute the normalising
constant. We demonstrate the efficacy of this approach with the reconstruction
of the group-group gravitational lens system CSWA 31, finding the source to be
composed of five merging spiral galaxies magnified by a factor of 13.Comment: Accepted for publication in MNRA
UniquID: A Quest to Reconcile Identity Access Management and the Internet of Things
The Internet of Things (IoT) has caused a revolutionary paradigm shift in
computer networking. After decades of human-centered routines, where devices
were merely tools that enabled human beings to authenticate themselves and
perform activities, we are now dealing with a device-centered paradigm: the
devices themselves are actors, not just tools for people. Conventional identity
access management (IAM) frameworks were not designed to handle the challenges
of IoT. Trying to use traditional IAM systems to reconcile heterogeneous
devices and complex federations of online services (e.g., IoT sensors and cloud
computing solutions) adds a cumbersome architectural layer that can become hard
to maintain and act as a single point of failure. In this paper, we propose
UniquID, a blockchain-based solution that overcomes the need for centralized
IAM architectures while providing scalability and robustness. We also present
the experimental results of a proof-of-concept UniquID enrolment network, and
we discuss two different use-cases that show the considerable value of a
blockchain-based IAM.Comment: 15 pages, 10 figure
Modification of silicon carbide fibers for use in SiC/Ti composites
The degradation of silicon carbide fibers during exposure to conditions typical of composite fabrication was investigated. The tensile strength of pristine fibers and fibers sputtered with thin metal coatings were determined before and after treatment at 870 C for one hour in vacuum. Each fiber strength distribution was related by an analytical procedure to a projected composite ultimate tensile strength (PC UTS). The results indicate that a thin aluminum diffusion barrier can yield a 150 percent increase in PC UTS over the baseline SiC/Ti system
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