343 research outputs found
The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters
Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator
with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal
clusters, as well as to theoretical predictions of jellium models, Woods--Saxon
and wine bottle potentials, and to the classification scheme using the 3n+l
pseudo quantum number. The 3-dimensional q-deformed harmonic oscillator
correctly predicts all experimentally observed magic numbers up to 1500 (which
is the expected limit of validity for theories based on the filling of
electronic shells), thus indicating that Uq(3), which is a nonlinear extension
of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic
oscillator, is a good candidate for being the symmetry of systems of alkali
metal clusters.Comment: 13 pages, LaTe
Expression of three intelectins in sheep and response to a Th2 environment
Sheep intelectin1 and sheep intelectin3 (sITLN1 and sITLN3) were cloned and sequenced. The amino acid sequences of sITLN1 and sITLN3 shared 86% and 91% homology with the previously cloned sheep intelectin2 (sITLN2), respectively. Expression of sITLN1 and sITLN3 transcript was demonstrated in abomasum, lung, colon and gastric lymph node, terminal rectum, skin, jejunum, mesenteric lymph node, ileal peyer’s patches, brain, kidney, liver, spleen, skin, ear pinna, heart and ovary in normal sheep tissues. sITLN2 transcript expression was restricted to the abomasal mucosa in normal sheep tissues. Using a non selective chicken anti-intelectin antibody, tissue intelectin protein was demonstrated in mucus neck cells in the abomasum, mucus cells in the colon, free mucus in ileum, goblet cells in the lung, small intestinal epithelium and brush border, epidermal layer of the skin and skin sebaceous glands. The expression of the three sITLN transcripts was examined in two nematode infections in sheep known to induce a Th2 response; a Teladorsagia circumcincta challenge infection model and a Dictyocaulus filaria natural infection. The three sITLN were absent in unchallenged naïve lambs and present in the abomasal mucosa of both naïve and immune lambs following T. circumcincta challenge infection. Upregulation of sITLN2 and sITLN3 was shown in sheep lung following D. filaria natural infection. Intelectins may play an important role in the mucosal response to nematode infections in ruminants
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Estimating worst case failure dependency with partial knowledge of the difficulty function
For systems using software diversity, well-established theories show that the expected probability of failure on demand (pfd) for two diverse program versions failing together will generally differ from what it would be if they failed independently. This is explained in terms of a “difficulty function” that varies between demands on the system. This theory gives insight, but no specific prediction unless we have some means to quantify the difficulty function. This paper presents a theory leading to a worst case measure of “average failure dependency” between diverse software, given only partial knowledge of the difficulty function. It also discusses the possibility of estimating the model parameters, with one approach based on an empirical analysis of previous systems implemented as logic networks, to support pre-development estimates of expected gain from diversity. The approach is illustrated using a realistic safety system example
Expression of Integrin-αE by Mucosal Mast Cells in the Intestinal Epithelium and Its Absence in Nematode-Infected Mice Lacking the Transforming Growth Factor-β1-Activating Integrin αvβ6
Peak intestinal mucosal mast cell (MMC) recruitment coincides with expulsion of Trichinella spiralis, at a time when the majority of the MMCs are located within the epithelium in BALB/c mice. Although expression of integrin-α(E)β(7) by MMCs has not been formally demonstrated, it has been proposed as a potential mechanism to account for the predominantly intraepithelial location of MMCs during nematode infection. Co-expression of integrin-α(E)β(7) and the MMC chymase mouse mast cell protease-1, by mouse bone marrow-derived mast cells, is strictly regulated by transforming growth factor (TGF)-β(1). However, TGF-β(1) is secreted as part of a latent complex in vivo and subsequent extracellular modification is required to render it biologically active. We now show, for the first time, that intraepithelial MMCs express integrin-α(E)β(7) in Trichinella-infected BALB/c and S129 mice. In S129 mice that lack the gene for the integrin-β(6) subunit and, as consequence, do not express the epithelial integrin-α(v)β(6), integrin-α(E) expression is virtually abolished and recruitment of MMCs into the intestinal epithelium is dramatically reduced despite significant overall augmentation of the MMC population. Because a major function of integrin-α(v)β(6) is to activate latent TGF-β(1,) these findings strongly support a role for TGF-β(1) in both the recruitment and differentiation of murine MMCs during nematode infection
“Getting into it”:People with intellectual disabilities’ experiences and views of Behavioural Activation and Guided Self-Help for depression
Background: No studies have explored the acceptability of Behavioural Activation and Guided Self-Help interventions for depression with people who have intellectual disabilities. Method: Twenty-five participants were purposively sampled from participants taking part in a trial comparing Behavioural Activation with a Guided Self-Help intervention. A framework analysis was used to analyse interviews covering participants’ expectations and views of therapy. Results: Participants were largely positive about both interventions. However, they identified specific aspects of each intervention which they had found helpful. All participants valued the therapeutic relationship. The participants also had a number of criticisms and suggestions for improving the therapies. A common concern was the time-limited nature of the interventions and a wish for longer-term help. Overall, both sets of participants felt the interventions had relevance for their wider lives. Conclusions: The participants reported having positive engagement with the therapies but expressed a wish for longer-term supportive relationships
Quantum walk on distinguishable non-interacting many-particles and indistinguishable two-particle
We present an investigation of many-particle quantum walks in systems of
non-interacting distinguishable particles. Along with a redistribution of the
many-particle density profile we show that the collective evolution of the
many-particle system resembles the single-particle quantum walk evolution when
the number of steps is greater than the number of particles in the system. For
non-uniform initial states we show that the quantum walks can be effectively
used to separate the basis states of the particle in position space and
grouping like state together. We also discuss a two-particle quantum walk on a
two- dimensional lattice and demonstrate an evolution leading to the
localization of both particles at the center of the lattice. Finally we discuss
the outcome of a quantum walk of two indistinguishable particles interacting at
some point during the evolution.Comment: 8 pages, 7 figures, To appear in special issue: "quantum walks" to be
published in Quantum Information Processin
High-Energy Aspects of Solar Flares: Overview of the Volume
In this introductory chapter, we provide a brief summary of the successes and
remaining challenges in understanding the solar flare phenomenon and its
attendant implications for particle acceleration mechanisms in astrophysical
plasmas. We also provide a brief overview of the contents of the other chapters
in this volume, with particular reference to the well-observed flare of 2002
July 23Comment: This is the introductory article for a monograph on the physics of
solar flares, inspired by RHESSI observations. The individual articles are to
appear in Space Science Reviews (2011
Hypoxic cancer–associated fibroblasts increase NCBP2-AS2/HIAR to promote endothelial sprouting through enhanced VEGF signaling
Intratumoral hypoxia causes the formation of dysfunctional blood vessels, which contribute to tumor metastasis and reduce the efficacy of therapeutic treatments. Blood vessels are embedded in the tumor stroma of which cancer-associated fibroblasts (CAFs) constitute a prominent cellular component. We found that hypoxic human mammary CAFs promoted angiogenesis in CAF-endothelial cell cocultures in vitro. Mass spectrometry–based proteomic analysis of the CAF secretome unraveled that hypoxic CAFs contributed to blood vessel abnormalities by altering their secretion of various pro- and anti-angiogenic factors. Hypoxia induced pronounced remodeling of the CAF proteome, including proteins that have not been previously related to this process. Among those, the uncharacterized protein NCBP2-AS2 that we renamed HIAR (hypoxia-induced angiogenesis regulator) was the protein most increased in abundance in hypoxic CAFs. Silencing of HIAR abrogated the pro-angiogenic and pro-migratory function of hypoxic CAFs by decreasing secretion of the pro-angiogenic factor VEGFA and consequently reducing VEGF/VEGFR downstream signaling in the endothelial cells. Our study has identified a regulator of angiogenesis and provides a map of hypoxia-induced molecular alterations in mammary CAFs
Cooling-induced SUMOylation of EXOSC10 down-regulates ribosome biogenesis.
The RNA exosome is essential for 3? processing of functional RNA species and degradation of aberrant RNAs in eukaryotic cells. Recent reports have defined the substrates of the exosome catalytic domains and solved the multimeric structure of the exosome complex. However, regulation of exosome activity remains poorly characterized, especially in response to physiological stress. Following the observation that cooling of mammalian cells results in a reduction in 40S:60S ribosomal subunit ratio, we uncover regulation of the nuclear exosome as a result of reduced temperature. Using human cells and an in vivo model system allowing whole-body cooling, we observe reduced EXOSC10 (hRrp6, Pm/Scl-100) expression in the cold. In parallel, both models of cooling increase global SUMOylation, leading to the identification of specific conjugation of SUMO1 to EXOSC10, a process that is increased by cooling. Furthermore, we define the major SUMOylation sites in EXOSC10 by mutagenesis and show that overexpression of SUMO1 alone is sufficient to suppress EXOSC10 abundance. Reducing EXOSC10 expression by RNAi in human cells correlates with the 3? preribosomal RNA processing defects seen in the cold as well as reducing the 40S:60S ratio, a previously uncharacterized consequence of EXOSC10 suppression. Together, this work illustrates that EXOSC10 can be modified by SUMOylation and identifies a physiological stress where this regulation is prevalent both in vitro and in vivo
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