36 research outputs found
Altered Patterns of Fungal Keratitis at a London Ophthalmic Referral Hospital: An Eight-Year Retrospective Observational Study
PURPOSE: In previous studies of fungal keratitis (FK)
from temperate countries, yeasts were the predominant
isolates, with ocular surface disease (OSD) being the
leading risk factor. Since the 2005–2006 outbreak of
contact lens (CL)-associated Fusarium keratitis, there
may have been a rise in CL-associated filamentary FK in
the United Kingdom. This retrospective case series investigated the patterns of FK from 2007 to 2014.
We compared these to 1994–2006 data from the same
hospital.
DESIGN: Retrospective observational study.
METHODS: All cases of FK presenting to Moorfields
Eye Hospital between 2007 and 2014 were identified.
The definition of FK was either a fungal organism isolated
by culture or fungal structures identified by light microscopy
(LM) of scrape material, histopathology, or
in vivo corneal confocal microscopy (IVCM). Main
outcome measure was cases of FK per year.
RESULTS: A total of 112 patients had confirmed FK.
Median age was 47.2 years. Between 2007 and 2014,
there was an increase in annual numbers of FK (Poisson
regression, P [ .0001). FK was confirmed using various
modalities: 79 (70.5%) by positive culture, 16 (14.3%)
by LM, and 61 (54.5%) by IVCM. Seventy-eight patients
(69.6%) were diagnosed with filamentary fungus alone,
28 (25%) with yeast alone, and 6 (5.4%) with mixed filamentary
and yeast infections. This represents an increase
in the proportion of filamentary fungal infections from
the pre-2007 data. Filamentary fungal and yeast infections
were associated with CL use and OSD, respectively.
CONCLUSIONS: The number of FK cases has increased.
This increase is due to CL-associated filamentary FK.
Clinicians should be aware of these changes, which
warrant epidemiologic investigations to identify modifiable
risk factors
CHEMOTHERAPY FOR ACANTHAMOEBA-KERATITIS
The design of modulation schemes for the physical layer network-coded two-way
MIMO relaying scenario is considered, with antennas at the relay R,
and antennas respectively at the end nodes A and B. We consider the
denoise-and-forward (DNF) protocol which employs two phases: Multiple access
(MA) phase and Broadcast (BC) phase. It is known for the network-coded SISO
two-way relaying that adaptively changing the networking coding map used at the
relay, also known as the denoising map, according to the channel conditions
greatly reduces the impact of multiple access interference which occurs at the
relay during the MA phase and all these network coding maps should satisfy a
requirement called the {\it exclusive law}. The network coding maps which
satisfy exclusive law can be viewed equivalently as Latin Rectangles. In this
paper, it is shown that for MIMO two-way relaying, deep fade occurs at the
relay when the row space of the channel fade coefficient matrix is a subspace
of a finite number of vector subspaces of which are
referred to as the singular fade subspaces. It is shown that proper choice of
network coding map can remove most of the singular fade subspaces, referred to
as the removable singular fade subspaces. For -PSK signal set, it
is shown that the number of non-removable singular fade subspaces is a small
fraction of the total number of singular fade subspaces. The Latin Rectangles
for the case when the end nodes use different number of antennas are shown to
be obtainable from the Latin Squares for the case when they use the same number
of antennas. Also, the network coding maps which remove all the removable
singular singular fade subspaces are shown to be obtainable from a small set of
Latin Squares.Comment: 17 pages, 17 figures, 1 table; some mistakes correcte