Transferrin-bound Yb2 uptake by U-87 MG cells and effect of Yb on proliferation of the cells

2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Deformation of the Fermi surface in the extended Hubbard model

The deformation of the Fermi surface induced by Coulomb interactions is investigated in the t-t'-Hubbard model. The interplay of the local U and extended V interactions is analyzed. It is found that exchange interactions V enhance small anisotropies producing deformations of the Fermi surface which break the point group symmetry of the square lattice at the Van Hove filling. This Pomeranchuck instability competes with ferromagnetism and is suppressed at a critical value of U(V). The interaction V renormalizes the t' parameter to smaller values what favours nesting. It also induces changes on the topology of the Fermi surface which can go from hole to electron-like what may explain recent ARPES experiments.Comment: 5 pages, 4 ps figure

Measured and calculated seismic velocities and densities for granulites from xenolith occurrences and adjacent exposed lower crustal sections: A comparative study from the North China craton

Granulites from the Neogene xenolith-bearing Hannuoba alkaline basalt and from the Manjinggou-Wayaokou exposed lower crustal section in the Archean Huai'an terrain, which occurs within and surrounds the Hannuoba basalt, provide a unique opportunity for a comparative study on petrophysical properties and composition of the lower crust represented by these two types of samples. P and S wave velocities and densities of 12 Hannuoba lower crustal xenoliths and one associated spinel lherzolite xenolith as well as nine granulites and granulite-facies metasedimentary rocks from the Archean Huai'an terrain were measured in laboratory at pressures up to 600 MPa and temperatures up to 600°C. Calculations of P and S wave velocities were also made for the same suite of samples based on modal mineralogy and single-crystal velocities whose variations with composition are considered by using microprobe analyses and velocities of end members. The measured and calculated Vp at room temperature and 600 MPa, where the microcrack effect is considered to be almost eliminated, agree within 4% for rocks from the Manjinggou-Wayaokou section and the adjacent Wutai-Jining upper crustal to upper lower crustal section. In contrast, the xenoliths show systematically lower measured Vp by up to 15% relative to calculated velocities, even if decompression-induced products of kelyphite and glass are taken into account. The lower measured velocities for xenoliths are attributed to grain boundary alteration and residual porosity. This implies that although granulite xenoliths provide direct information about lower crustal constitution and chemical composition, they are not faithful samples for studying in situ seismic properties of the lower crust in terms of measured velocities due to alterations during their entrainment to the surface, which changes their physical properties significantly. In this respect, granulites from high-grade terrains are better samples because they are not subjected to significant changes during their slow transport to the surface and because physical properties depend primarily on mineralogy in addition to pressure and temperature. On the other hand, calculated velocities for granulite xenoliths are consistent with velocities for granulites from terrains, suggesting that they can be also used to infer lower crust composition by correlating with results from seismic refraction studies. Copyright 2000 by the American Geophysical Union.published_or_final_versio

Collaborative Gaze Channelling for Improved Cooperation During Robotic Assisted Surgery

The use of multiple robots for performing complex tasks is becoming a common practice for many robot applications. When different operators are involved, effective cooperation with anticipated manoeuvres is important for seamless, synergistic control of all the end-effectors. In this paper, the concept of Collaborative Gaze Channelling (CGC) is presented for improved control of surgical robots for a shared task. Through eye tracking, the fixations of each operator are monitored and presented in a shared surgical workspace. CGC permits remote or physically separated collaborators to share their intention by visualising the eye gaze of their counterparts, and thus recovers, to a certain extent, the information of mutual intent that we rely upon in a vis-à-vis working setting. In this study, the efficiency of surgical manipulation with and without CGC for controlling a pair of bimanual surgical robots is evaluated by analysing the level of coordination of two independent operators. Fitts' law is used to compare the quality of movement with or without CGC. A total of 40 subjects have been recruited for this study and the results show that the proposed CGC framework exhibits significant improvement (p<0.05) on all the motion indices used for quality assessment. This study demonstrates that visual guidance is an implicit yet effective way of communication during collaborative tasks for robotic surgery. Detailed experimental validation results demonstrate the potential clinical value of the proposed CGC framework. © 2012 Biomedical Engineering Society.link_to_subscribed_fulltex

To respond or not to respond - a personal perspective of intestinal tolerance

For many years, the intestine was one of the poor relations of the immunology world, being a realm inhabited mostly by specialists and those interested in unusual phenomena. However, this has changed dramatically in recent years with the realization of how important the microbiota is in shaping immune function throughout the body, and almost every major immunology institution now includes the intestine as an area of interest. One of the most important aspects of the intestinal immune system is how it discriminates carefully between harmless and harmful antigens, in particular, its ability to generate active tolerance to materials such as commensal bacteria and food proteins. This phenomenon has been recognized for more than 100 years, and it is essential for preventing inflammatory disease in the intestine, but its basis remains enigmatic. Here, I discuss the progress that has been made in understanding oral tolerance during my 40 years in the field and highlight the topics that will be the focus of future research

Search for Charged Higgs Bosons in e+e- Collisions at \sqrt{s} = 189 GeV

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a strange quark or into a tau lepton and its associated neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. A lower limit of 65.5 GeV on the charged Higgs mass is derived at 95 % confidence level, independent of the decay branching ratio Br(H^{+/-} -> tau nu)

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

Altered expression of the TCR signaling related genes CD3 and FcεRIγ in patients with aplastic anemia

<p>Abstract</p> <p>Background</p> <p>Aplastic anemia (AA) is characterized by pancytopenia and bone marrow hypoplasia, which results from immune-mediated hematopoiesis suppression. Understanding the pathophysiology of the immune system, particularly T cells immunity, has led to improved AA treatment over the past decades. However, primary and secondary failure after immunosuppressive therapy is frequent. Thus, knowledge of the immune mechanisms leading to AA is crucial to fundamentally understand the disease.</p> <p>Findings</p> <p>To elucidate the T cell receptor (TCR) signal transduction features in AA, the expression levels of CD3γ, δ, ε and ζ chain and FcεRIγ genes, which are involved in TCR signal transduction, and the negative correlation of the expression levels between the CD3ζ and FcεRIγ genes in T cells from peripheral blood mononuclear cells (PBMCs) were analyzed. Real-time RT-PCR using the SYBR Green method was used to detect the expression level of these genes in PBMCs from 18 patients with AA and 14 healthy individuals. The β2microglobulin gene (β2M) was used as an endogenous reference. The expression levels of the CD3γ, CD3δ, CD3ε and CD3ζ genes in patients with AA were significantly increased compared to a healthy control group, whereas the FcεRIγ gene expression level was significantly decreased in patients with AA in comparison with the healthy control group. Moreover, the negative correlation of the expression levels between the CD3ζ and FcεRIγ genes was lost.</p> <p>Conclusions</p> <p>To our knowledge, this is the first report of the CD3γ, CD3δ, CD3ε, CD3ζ and FcεRIγ gene expression in patients with AA. The abnormally expressed TCR signaling related genes may relate to T cells dysfunction in AA.</p