2,055 research outputs found
Boundedness of dyadic paraproducts on matrix weighted
In this paper, we show that dyadic paraproducts with in dyadic
BMO are bounded on matrix weighted if is a matrix
weight.Comment: This paper has been withdrawn, and is vastly generalized by
https://arxiv.org/abs/1507.0403
Magnetic Properties of a-Si films doped with rare-earth elements
Amorphous silicon films doped with Y, La, Gd, Er, and Lu rare-earth elements
(a-Si:RE) have been prepared by co-sputtering and studied by means of electron
spin resonance (ESR), dc-magnetization, ion beam analysis, optical
transmission, and Raman spectroscopy. For comparison the magnetic properties of
laser-crystallized and hydrogenated a-Si:RE films were also studied. It was
found that the rare-earth species are incorporated in the a-Si:RE films in the
RE3+ form and that the RE-doping depletes the neutral dangling bonds (D0)
density. The reduction of D0 density is significantly larger for the magnetic
REs (Gd3+ and Er3+) than for the non-magnetic ones (Y3+, La3+, Lu3+). These
results are interpreted in terms of a strong exchange-like interaction, J RE-DB
SRE SDB, between the spin of the magnetic REs and that of the D0. All our
Gd-doped Si films showed basically the same broad ESR Gd3+ resonance (DHpp ~
850 Oe) at g ~ 2.01, suggesting the formation of a rather stable RE-Si complex
in these films.Comment: 15 pages, 7 figure
The expression and signalling patterns of CD180 toll like receptor in Chronic Lymphocytic Leukaemia (CLL)
Chronic lymphocytic leukaemia (CLL) is characterised by a progressive accumulation of mature CD5+CD20+CD23+ lymphocytes. Despite the remarkable progress in our understanding of the immunobiology of CLL, the aetiology of the disease remains unknown. The consensus is that CLL cells are driven by (auto)antigen(s) through the B cell receptor (BCR) and are regulated by a variety of signals received from the microenvironment, including toll-like receptors (TLR).Our group has previously shown that engagement of the CD180 orphan TLR expressed by approximately 60% of CLL cells, can re-wire the sIgM-mediated signalling from a pro-survival pathway, involving phosphatidylinositol-4,5-bisphosphate3-kinase (PI3K) and protein kinase B (AKT) to the potentially pro-apoptotic pathway through mitogen-activated protein kinase (p38MAPK).
However, little is known about the function of the other BCR - sIgD in CLL and its possible interaction with CD180. Here we studied intracellular signalling and apoptosis of CLL cells following sole or sequential ligation of CD180 and sIgD.
Our data indicated that following sequential ligation of CD180 and sIgD, CLL samples demonstrated enhanced p38MAPK phosphorylation leading to increased apoptosis of CLL cells indicating synergistic relationship between CD180 and sIgD. To better understand the prognostic importance of CD180 expression we sought to determine whether CD180 and other prognostic markers such as CD38 and ZAP70 displayed any correlation with the known cytogenetic aberrations:TP53 and DLEU1. Our results suggested that CLL cells with DLEU1 deletion are characterised by the negative expression of both, CD180 and CD38, and this might have a significance for CLL prognosis.
To explain this correlation, we hypothesised that interaction of CLL cells with their microenvironment through TLRs leads to the expansion of leukaemic clones, in vivo, in lymph nodes. Our results indicated that CD180 is heterogeneously expressed in the paraffin tissue sections of the lymph nodes of CLL patients and its expression positively correlates with the expression of Ki-67.
Our data demonstrated, that although CD180 expression and signaling might have negative prognostic importance in CLL due to the enhanced proliferation of leukaemic cells, its interaction with sIgD would re-direct leukaemic cells towards apoptosis thus opening new opportunities for the disease immunotherapy
Pair HMM based gap statistics for re-evaluation of indels in alignments with affine gap penalties: Extended Version
Although computationally aligning sequence is a crucial step in the vast
majority of comparative genomics studies our understanding of alignment biases
still needs to be improved. To infer true structural or homologous regions
computational alignments need further evaluation. It has been shown that the
accuracy of aligned positions can drop substantially in particular around gaps.
Here we focus on re-evaluation of score-based alignments with affine gap
penalty costs. We exploit their relationships with pair hidden Markov models
and develop efficient algorithms by which to identify gaps which are
significant in terms of length and multiplicity. We evaluate our statistics
with respect to the well-established structural alignments from SABmark and
find that indel reliability substantially increases with their significance in
particular in worst-case twilight zone alignments. This points out that our
statistics can reliably complement other methods which mostly focus on the
reliability of match positions.Comment: 17 pages, 7 figure
A critical evaluation of network and pathway based classifiers for outcome prediction in breast cancer
Recently, several classifiers that combine primary tumor data, like gene
expression data, and secondary data sources, such as protein-protein
interaction networks, have been proposed for predicting outcome in breast
cancer. In these approaches, new composite features are typically constructed
by aggregating the expression levels of several genes. The secondary data
sources are employed to guide this aggregation. Although many studies claim
that these approaches improve classification performance over single gene
classifiers, the gain in performance is difficult to assess. This stems mainly
from the fact that different breast cancer data sets and validation procedures
are employed to assess the performance. Here we address these issues by
employing a large cohort of six breast cancer data sets as benchmark set and by
performing an unbiased evaluation of the classification accuracies of the
different approaches. Contrary to previous claims, we find that composite
feature classifiers do not outperform simple single gene classifiers. We
investigate the effect of (1) the number of selected features; (2) the specific
gene set from which features are selected; (3) the size of the training set and
(4) the heterogeneity of the data set on the performance of composite feature
and single gene classifiers. Strikingly, we find that randomization of
secondary data sources, which destroys all biological information in these
sources, does not result in a deterioration in performance of composite feature
classifiers. Finally, we show that when a proper correction for gene set size
is performed, the stability of single gene sets is similar to the stability of
composite feature sets. Based on these results there is currently no reason to
prefer prognostic classifiers based on composite features over single gene
classifiers for predicting outcome in breast cancer
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