622 research outputs found
Effects of fibre content and textile structure on dynamic-mechanical and shape-memory properties of ELO/flax biocomposites
Biocomposites were prepared using epoxidized linseed oil (ELO) and flax fibre
reinforcements in different assemblies. ELO was cured by two different anhydrides to
check how its thermomechanical properties can be influenced. As reinforcements
nonwoven mat, twill weave and quasi-unidirectional textile fabrics with two different
yarn finenesses were used. Their reinforcing effect was determined in dynamic
mechanical analysis (DMA) in flexure. DMA served also to determine the glass
transition temperature (Tg). Shape memory properties were derived from quasiunconstrained
flexural tests performed near to the Tg of the ELO and its biocomposites.
Flax reinforcement reduced the Tg that was attributed to off-stoichiometry owing to
chemical reaction between the hydroxyl groups of flax and anhydride hardener. The
shape memory parameters were moderate or low. They were affected by both textile
content and type
Exact, time-independent estimation of clone size distributions in normal and mutated cells
Biological tools such as genetic lineage tracing, three dimensional confocal microscopy and next generation DNA sequencing are providing new ways to quantify the distribution of clones of normal and mutated cells. Population-wide clone size distributions in vivo are complicated by multiple cell types, and overlapping birth and death processes. This has led to the increased need for mathematically informed models to understand their biological significance. Standard approaches usually require knowledge of clonal age. We show that modelling on clone size independent of time is an alternative method that offers certain analytical advantages; it can help parameterize these models, and obtain distributions for counts of mutated or proliferating cells, for example. When applied to a general birth-death process common in epithelial progenitors this takes the form of a gamblers ruin problem, the solution of which relates to counting Motzkin lattice paths. Applying this approach to mutational processes, an alternative, exact, formulation of the classic Luria Delbruck problem emerges. This approach can be extended beyond neutral models of mutant clonal evolution, and also describe some distributions relating to sub-clones within a tumour. The approaches above are generally applicable to any Markovian branching process where the dynamics of different "coloured" daughter branches are of interest
A nodulo-cystic eumycetoma caused by Pyrenochaeta romeroi in a renal transplant recipient: A case report
<p>Abstract</p> <p>Introduction</p> <p><it>Pyrenochaeta romeroi </it>(<it>P. romeroi</it>) is a saprophytic fungus found in soil and plants. The fungal spores can be introduced into deeper tissues by trauma. It causes eumycetoma, which affects skin and subcutaneous tissues.</p> <p>Case presentation</p> <p>A 57-year-old South Asian man presented with a painless, nodular lesion (1 cm Ă 0.5 cm) on the left knee. He had had a renal transplant eight months earlier for end-stage renal failure. The patient was on tacrolimus, mycophenolate mofetil and prednisolone for immunosuppression. The lesion had progressed dramatically (to 5 cm Ă 5 cm) despite antibiotic treatment. The size and location of the lesion was severely affecting his quality of life, so an excision biopsy was performed. Nuclear ribosomal repeat-region sequencing confirmed the causative organism as <it>P. romeroi</it>. An <it>in vitro </it>antifungal susceptibility test demonstrated that <it>P. romeroi </it>was sensitive to voriconazole. Following a successful surgical removal, voriconazole was continued orally for two months.</p> <p>Conclusion</p> <p>To the best of our knowledge, we are reporting the first case of Eumycetoma caused by <it>P. romeroi </it>in a renal transplant recipient. Physicians should be aware of this rare fungal disease in transplant recipients. We recommend a combination of medical and surgical management in these immunosuppressed patients.</p
The CAP cancer protocols â a case study of caCORE based data standards implementation to integrate with the Cancer Biomedical Informatics Grid
BACKGROUND: The Cancer Biomedical Informatics Grid (caBIGâ˘) is a network of individuals and institutions, creating a world wide web of cancer research. An important aspect of this informatics effort is the development of consistent practices for data standards development, using a multi-tier approach that facilitates semantic interoperability of systems. The semantic tiers include (1) information models, (2) common data elements, and (3) controlled terminologies and ontologies. The College of American Pathologists (CAP) cancer protocols and checklists are an important reporting standard in pathology, for which no complete electronic data standard is currently available. METHODS: In this manuscript, we provide a case study of Cancer Common Ontologic Representation Environment (caCORE) data standard implementation of the CAP cancer protocols and checklists model â an existing and complex paper based standard. We illustrate the basic principles, goals and methodology for developing caBIG⢠models. RESULTS: Using this example, we describe the process required to develop the model, the technologies and data standards on which the process and models are based, and the results of the modeling effort. We address difficulties we encountered and modifications to caCORE that will address these problems. In addition, we describe four ongoing development projects that will use the emerging CAP data standards to achieve integration of tissue banking and laboratory information systems. CONCLUSION: The CAP cancer checklists can be used as the basis for an electronic data standard in pathology using the caBIG⢠semantic modeling methodology
Planet Populations as a Function of Stellar Properties
Exoplanets around different types of stars provide a window into the diverse
environments in which planets form. This chapter describes the observed
relations between exoplanet populations and stellar properties and how they
connect to planet formation in protoplanetary disks. Giant planets occur more
frequently around more metal-rich and more massive stars. These findings
support the core accretion theory of planet formation, in which the cores of
giant planets form more rapidly in more metal-rich and more massive
protoplanetary disks. Smaller planets, those with sizes roughly between Earth
and Neptune, exhibit different scaling relations with stellar properties. These
planets are found around stars with a wide range of metallicities and occur
more frequently around lower mass stars. This indicates that planet formation
takes place in a wide range of environments, yet it is not clear why planets
form more efficiently around low mass stars. Going forward, exoplanet surveys
targeting M dwarfs will characterize the exoplanet population around the lowest
mass stars. In combination with ongoing stellar characterization, this will
help us understand the formation of planets in a large range of environments.Comment: Accepted for Publication in the Handbook of Exoplanet
Optomechanical Crystals
Structured, periodic optical materials can be used to form photonic crystals
capable of dispersing, routing, and trapping light. A similar phenomena in
periodic elastic structures can be used to manipulate mechanical vibrations.
Here we present the design and experimental realization of strongly coupled
optical and mechanical modes in a planar, periodic nanostructure on a silicon
chip. 200-Terahertz photons are co-localized with mechanical modes of Gigahertz
frequency and 100-femtogram mass. The effective coupling length, which
describes the strength of the photon-phonon interaction, is as small as 2.9
microns, which, together with minute oscillator mass, allows all-optical
actuation and transduction of nanomechanical motion with near quantum-limited
sensitivity. Optomechanical crystals have many potential applications, from
RF-over-optical communication to the study of quantum effects in mesoscopic
mechanical systems.Comment: 16 pages, 7 figure
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
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