1,503 research outputs found
Alpha/beta and gamma interferons are induced by infection with noncytopathic bovine viral diarrhea virus in vivo
In contrast to the results of previous in vitro studies, experimental infection of calves with noncytopathic bovine viral diarrhea virus (ncpBVDV) was found to induce strong alpha/beta and gamma interferon responses in gnotobiotic animals. These responses were associated with depressed levels of transforming growth factor β (TGF-β) in serum. The results of this study indicate that the immunosuppression caused by ncpBVDV is not associated with low interferon responses or elevated levels of TGF-β
Friction behaviour of hydrophilic lubricious coatings for medical device applications
The friction behaviour of new chitosan derivative coatings obtained by chemical modification of chitosan
with fatty acids (linoleic and dilinoleic acid) has been investigated in order to explore their potential as
endovascular catheter coatings and to benchmark them against commercially available coatings used in
endovascular catheter applications. An in vitro tribological system was developed that was intended to
represent to a limited extent the in vivo tribological conditions of a typical endovascular catheterization
procedure. Continuous reciprocating sliding tests were carried out with uncoated and coated polymer
specimens. The results showed that all of the coatings tested decreased the coefficient of friction
compared to the uncoated polymer. Compared to a neat chitosan coating, the chitosan derivative
coatings showed a clear reduction in the coefficient of friction to levels similar to those of the
commercially-available coatings. A comparison between the friction results and contact angle measurements
carried out on the coatings indicated that a range of contact angle values exists for which the
friction coefficient is at a minimum. The reason for this is unclear and further studies are required in
order to confirm and investigate the trend, especially within the context of hydrophilic lubricious
coating development
Cost of care of chronic non-communicable diseases in Jamaican patients: the role of obesity
OBJECTIVE: To estimate the economic cost of Chronic Non-Communicable Diseases (CNCDs) and the portion attributable to obesity among patients in Jamaica.METHODS: The cost-of-illness approach was used to estimate the cost of care in a hospital setting in Jamaica for type 2 diabetes mellitus, hypertension, coronary heart disease, stroke, gallbladder disease, breast cancer, colon cancer, osteoarthritis, and high cholesterol. Cost and service utilization data were collected from the hospital records of all patients with these diseases who visited the University Hospital of the West Indies (UHWI) during 2006. Patients were included in the study if they were between15 and 74 years of age and if female, were not pregnant during that year. Costs were categorized as direct or indirect. Direct costs included costs for prescription drugs, consultation visits (emergency and clinic visits), hospitalizations, allied health services, diagnostic and treatment procedures. Indirect costs included costs attributed to premature mortality, disability (permanent and temporary), and absenteeism. Indirect costs were discounted at 3% rate.RESULTS: The sample consisted of 554 patients (40%) males (60%) females. The economic burden of the nine diseases was estimated at US 1,157,173 (males 23%; females 77%). Total direct cost was estimated at US 1,932,241 with female patients accounting for 50.6% of this cost. The greater cost among women was not found to be statistically significant. Overall, on a per capita basis, males and females accrued similar costs-of-illness (US 10,758.18).CONCLUSIONS: In a country with per capita GDP of less than US 10,239 for CNCDs is excessive and has detrimental implications for the health and development of Jamaica
Rotation-stimulated structures in the CN and C3 comae of comet 103P/Hartley 2 around the EPOXI encounter
In late 2010 a Jupiter Family comet 103P/Hartley 2 was a subject of an
intensive world-wide investigation. On UT October 20.7 the comet approached the
Earth within only 0.12 AU, and on UT November 4.6 it was visited by NASA's
EPOXI spacecraft. We joined this international effort and organized an
observing campaign. The images of the comet were obtained through narrowband
filters using the 2-m telescope of the Rozhen National Astronomical
Observatory. They were taken during 4 nights around the moment of the EPOXI
encounter. Image processing methods and periodicity analysis techniques were
used to reveal transient coma structures and investigate their repeatability
and kinematics. We observe shells, arc-, jet- and spiral-like patterns, very
similar for the CN and C3 comae. The CN features expanded outwards with the
sky-plane projected velocities between 0.1 to 0.3 km/s. A corkscrew structure,
observed on November 6, evolved with a much higher velocity of 0.66 km/s.
Photometry of the inner coma of CN shows variability with a period of
18.32+/-0.30 h (valid for the middle moment of our run, UT 2010 Nov. 5.0835),
which we attribute to the nucleus rotation. This result is fully consistent
with independent determinations around the same time by other teams. The
pattern of repeatability is, however, not perfect, which is understendable
given the suggested excitation of the rotation state, and the variability
detected in CN correlates well with the cyclic changes in HCN, but only in the
active phases. The revealed coma structures, along with the snapshot of the
nucleus orientation obtained by EPOXI, let us estimate the spin axis
orientation. We obtained RA=122 deg, Dec=+16 deg (epoch J2000.0), neglecting at
this point the rotational excitation.Comment: 9 pages, 10 figures, submitted to Astron. Astrophy
The <i>Rosetta</i> Mission and the Chemistry of Organic Species in Comet 67P/Churyumov–Gerasimenko
Comets are regarded as probably the most primitive of solar system objects, preserving a record of the materials from which the solar system aggregated. Key amongst their components are organic compounds – molecules that may trace their heritage to the interstellar medium from which the protosolar nebula eventually emerged. The most recent cometary space mission, Rosetta, carried instruments designed to characterize, in unprecedented detail, the organic species in comet 67P/Churyumov–Gerasimenko (67P). Rosetta was the first mission to match orbits with a comet and follow its evolution over time, and also the first mission to land scientific instruments on a comet surface. Results from the mission revealed a greater variety of molecules than previously identified and indicated that 67P contained both primitive and processed organic entities
Niobium based intermetallics as a source of high-current/high-magnetic field superconductors
The article is focused on low temperature intermetallic A15 superconducting
wires development for Nuclear Magnetic Resonance, NMR, and Nuclear Magnetic
Imaging, MRI, magnets and also on cryogen-free magnets. There are many other
applications which would benefit from new development such as future Large
Hadron Collider to be built from A15 intermetallic conductors. This paper
highlights the current status of development of the niobium based
intermetallics with special attention to Nb 3 (Al 1-x, Ge x). Discussion is
focused on the materials science aspects of conductor manufacture, such as
b-phase (A15) formation, with particular emphasis on the maximisation of the
superconducting parameters, such as critical current density, Jc, critical
temperature, Tc, and upper critical field, Hc2 . Many successful manufacturing
techniques of the potential niobium-aluminide intermetallic superconducting
conductors, such as solid-state processing, liquid-solid processing, rapid
heating/cooling processes, are described, compared and assessed. Special
emphasis has been laid on conditions under which the Jc (B) peak effect occurs
in some of the Nb3(Al,Ge) wires. A novel electrodeoxidizing method developed in
Cambridge whereby the alloys and intermetallics are produced cheaply making all
superconducting electromagnetic devices, using low cost LTCs, more cost
effective is presented.This new technique has potential to revolutionise the
existing superconducting industry enabling reduction of cost orders of
magnitude.Comment: Paper presented at EUCAS'01 conference, Copenhagen, 26-30 August 200
A quantitative approach for measuring the reservoir of latent HIV-1 proviruses.
A stable latent reservoir for HIV-1 in resting CD4+ T cells is the principal barrier to a cure1-3. Curative strategies that target the reservoir are being tested4,5 and require accurate, scalable reservoir assays. The reservoir was defined with quantitative viral outgrowth assays for cells that release infectious virus after one round of T cell activation1. However, these quantitative outgrowth assays and newer assays for cells that produce viral RNA after activation6 may underestimate the reservoir size because one round of activation does not induce all proviruses7. Many studies rely on simple assays based on polymerase chain reaction to detect proviral DNA regardless of transcriptional status, but the clinical relevance of these assays is unclear, as the vast majority of proviruses are defective7-9. Here we describe a more accurate method of measuring the HIV-1 reservoir that separately quantifies intact and defective proviruses. We show that the dynamics of cells that carry intact and defective proviruses are different in vitro and in vivo. These findings have implications for targeting the intact proviruses that are a barrier to curing HIV infection
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Evidence of neutral transcriptome evolution in plants
The transcriptome of an organism is its set of gene transcripts (mRNAs) at a defined spatial and temporal locus. Because gene expression is affected markedly by
environmental and developmental perturbations, it is widely assumed that transcriptome divergence among taxa represents adaptive phenotypic selection. This assumption has been challenged by neutral theories which propose that stochastic
processes drive transcriptome evolution. To test for evidence of neutral transcriptome evolution in plants, we quantified 18 494 gene transcripts in nonsenescent leaves of 14 taxa of Brassicaceae using robust cross-species transcriptomics which includes a two-step physical and in silicobased normalization procedure based on DNA similarity among taxa. Transcriptome divergence correlates positively with evolutionary distance between taxa and with variation in gene expression among samples. Results are similar for pseudogenes and chloroplast genes evolving at different rates. Remarkably, variation in transcript abundance among root-cell samples correlates positively with
transcriptome divergence among root tissues and among taxa.
Because neutral processes affect transcriptome evolution in plants, many differences in gene expression among or within taxa may be nonfunctional, reflecting ancestral
plasticity and founder effects. Appropriate null models are required when comparing transcriptomes in space and time
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Change in convergence and accommodation after two weeks of eye exercises in typical young adults
Abstract: Introduction
Although eye exercises appear to help heterophoria, convergence insufficiency and intermittent strabismus, true treatment effects can be confounded by placebo, practice and encouragement factors. This study assessed objective changes in vergence and accommodation responses in typical naïve young adults after two weeks of exercises compared to control conditions to assess the extent of treatment effects occur above other factors.
Methods
156 asymptomatic young adults were randomly assigned to 6 exercise groups or 2 no-treatment groups. Treatment targeted i) accommodation, ii)vergence, iii) both, iv) convergence>accommodation, v)accommodation>convergence, or vi) a placebo. All were re-tested under identical conditions, except for the second control group who were
additionally encouraged during testing. Objective accommodation and vergence were assessed to a range of targets moving in depth containing combinations of blur, disparity and proximity/looming cues.
Results
Response gain improved more for less naturalistic targets where more improvement was possible. Convergence exercises improved vergence for near across all targets (P=.035). Mean accommodation changed similarly,but non-significantly. No other treatment group differed significantly from the non-encouraged control group, while encouraging effort produced significantly increased vergence (P=.004) and accommodation (P=.005) gains in the other control group.
Conclusions
True treatment effects were small, only significantly better after vergence exercises to a non-accommodative target, and were rarely related to response they were designed to improve. Exercising accommodation without convergence made no difference to accommodation to cues
containing detail. Additional effort improved objective responses the most, so should be controlled carefully in research, and considered when auditing treatment
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