7,828 research outputs found
Incidence of blood-related work accidents among health workers in a government hospital in Benin City, Nigeria
Accidents are hazards to which health workers are exposed. Hazards may
be physical, chemical, biological, mechanical or psychosocial.
Mechanical hazards are very common in the health industry because of
the frequent use of pointed and sharp instruments such as needles,
scalpel and knives. This six-month (June 1999 and June 2000)
longitudinal incidence study was carried out at the Central Hospital,
Benin City, Nigeria, as a follow-up on a previous cross-sectional study
on frequency of blood-related work accidents in the same hospital. All
the doctors, laboratory workers and 50% of nurses were included in the
study. The nurses were selected using stratified random sampling
method. Two hundred and fourteen health care workers started the
follow-up study, out of which 146 were left at the end of the six-month
period, giving an attrition rate of 31.8%. Results shows that contact
with patients' blood with ungloved hands, blood splashes on the face
and other parts of the body, needle pricks, cuts from drug ampoules and
glove perforation during surgery were the major work-related
accidents/injuries during the six-month follow-up. This is similar to
findings from the retrospective study. The frequencies of various
accidents were higher during the six-month follow-up (incidence study)
than the six months prior to the study (retrospective study). Combining
all the health workers, the incidence densities of these five major
work-related accidents were between 3.6 per person years (ppy) to
9.5ppy. These incidence densities were all significantly higher for
doctors than nurses or laboratory workers. There is an urgent need to
reduce the incidence of these work-related accidents/injuries in order
to reduce the chances of health workers developing occupationally
acquired diseases
Quantification of the Frequency and Multiplicity of Infection of Respiratory- and Lymph Node–Resident Dendritic Cells During Influenza Virus Infection
Background: Previous studies have demonstrated that DC differentially regulate influenza A virus (IAV)–specific CD8 T cell responses in vivo during high and low dose IAV infections. Furthermore, in vitro infection of DC with IAV at low versus high multiplicities of infection (MOI) results in altered cytokine production and a reduced ability to prime naïve CD8 T cell responses. Flow cytometric detection of IAV proteins within DC, a commonly used method for detection of cellular IAV infection, does not distinguish between the direct infection of these cells or their uptake of viral proteins from dying epithelial cells. Methods/Principal Findings: We have developed a novel, sensitive, single-cell RT-PCR–based approach to assess the infection of respiratory DC (rDC) and lymph node (LN)-resident DC (LNDC) following high and low dose IAV infections. Our results show that, while a fraction of both rDC and LNDC contain viral mRNA following IAV infection, there is little correlation between the percentage of rDC containing viral mRNA and the initial IAV inoculum dose. Instead, increasing IAV inoculums correlate with augmented rDC MOI. Conclusion/Significance: Together, our results demonstrate a novel and sensitive method for the detection of direct IAV infection at the single-cell level and suggest that the previously described ability of DC to differentially regulate IAV-specific T cell responses during high and low dose IAV infections could relate to the MOI of rDC within the LN rather than th
Keratoconus associated with choroidal neovascularization: a case report
<p>Abstract</p> <p>Introduction</p> <p>Keratoconus and choroidal neovascularization can occur as a result of dysfunction of the epithelium and its basement membrane.</p> <p>Case presentation</p> <p>A 17-year-old Asian man, who was diagnosed with myopic choroidal neovascularization in both eyes and who subsequently underwent intravitreal injection of ranibizumab (Lucentis<sup>®</sup>) five times over six months, presented with further vision decrease and pain in his right eye. Examination showed corneal steepening and stromal edema in the inferocentral cornea of his right eye, both of which were indicative of advanced keratoconus with acute hydrops. Corneal topography also showed features consistent with keratoconus in his left eye. Fluorescein angiography and optical coherence tomography revealed choroidal neovascularization-associated subretinal hemorrhages and lacquer cracks in both eyes.</p> <p>Conclusion</p> <p>Keratoconus and choroidal neovascularization, possibly resulting from dysfunction of the epithelium and its basement membrane, can occur together in the same individual. This would suggest a possible connection in pathogenesis between these two conditions.</p
Supersymmetric 3-branes on smooth ALE manifolds with flux
We construct a new family of classical BPS solutions of type IIB supergravity
describing 3-branes transverse to a 6-dimensional space with topology R^2*ALE.
They are characterized by a non-trivial flux of the supergravity 2-forms
through the homology 2-cycles of a generic smooth ALE manifold. Our solutions
have two Killing spinors and thus preserve N=2 supersymmetry. They are
expressed in terms of a quasi harmonic function H (the ``warp factor''), whose
properties we study in the case of the simplest ALE, namely the Eguchi-Hanson
manifold. The equation for H is identified as an instance of the confluent Heun
equation. We write explicit power series solutions and solve the recurrence
relation for the coefficients, discussing also the relevant asymptotic
expansions. While, as in all such N=2 solutions, supergravity breaks down near
the brane, the smoothing out of the vacuum geometry has the effect that the
warp factor is regular in a region near the cycle. We interpret the behavior of
the warp factor as describing a three-brane charge ``smeared'' over the cycle
and consider the asymptotic form of the geometry in that region, showing that
conformal invariance is broken even when the complex type IIB 3-form field
strength is assumed to vanish. We conclude with a discussion of the basic
features of the gauge theory dual.Comment: latex, 36 pages (26 + appendix). Some statements on the gauge dual
made more precise. Final version to appear on NP
Formation of Supermassive Black Holes
Evidence shows that massive black holes reside in most local galaxies.
Studies have also established a number of relations between the MBH mass and
properties of the host galaxy such as bulge mass and velocity dispersion. These
results suggest that central MBHs, while much less massive than the host (~
0.1%), are linked to the evolution of galactic structure. In hierarchical
cosmologies, a single big galaxy today can be traced back to the stage when it
was split up in hundreds of smaller components. Did MBH seeds form with the
same efficiency in small proto-galaxies, or did their formation had to await
the buildup of substantial galaxies with deeper potential wells? I briefly
review here some of the physical processes that are conducive to the evolution
of the massive black hole population. I will discuss black hole formation
processes for `seed' black holes that are likely to place at early cosmic
epochs, and possible observational tests of these scenarios.Comment: To appear in The Astronomy and Astrophysics Review. The final
publication is available at http://www.springerlink.co
The Formation of the First Massive Black Holes
Supermassive black holes (SMBHs) are common in local galactic nuclei, and
SMBHs as massive as several billion solar masses already exist at redshift z=6.
These earliest SMBHs may grow by the combination of radiation-pressure-limited
accretion and mergers of stellar-mass seed BHs, left behind by the first
generation of metal-free stars, or may be formed by more rapid direct collapse
of gas in rare special environments where dense gas can accumulate without
first fragmenting into stars. This chapter offers a review of these two
competing scenarios, as well as some more exotic alternative ideas. It also
briefly discusses how the different models may be distinguished in the future
by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First
Galaxies - Theoretical Predictions and Observational Clues", Springer
Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B.
Mobasher, in pres
The Formation and Evolution of the First Massive Black Holes
The first massive astrophysical black holes likely formed at high redshifts
(z>10) at the centers of low mass (~10^6 Msun) dark matter concentrations.
These black holes grow by mergers and gas accretion, evolve into the population
of bright quasars observed at lower redshifts, and eventually leave the
supermassive black hole remnants that are ubiquitous at the centers of galaxies
in the nearby universe. The astrophysical processes responsible for the
formation of the earliest seed black holes are poorly understood. The purpose
of this review is threefold: (1) to describe theoretical expectations for the
formation and growth of the earliest black holes within the general paradigm of
hierarchical cold dark matter cosmologies, (2) to summarize several relevant
recent observations that have implications for the formation of the earliest
black holes, and (3) to look into the future and assess the power of
forthcoming observations to probe the physics of the first active galactic
nuclei.Comment: 39 pages, review for "Supermassive Black Holes in the Distant
Universe", Ed. A. J. Barger, Kluwer Academic Publisher
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